Organic electroluminescence element and their preparation

Organic electroluminescent element and manufacturing method thereof

[Technical Field]

The present invention relates to organic electroluminescent elements (hereinafter referred to as "organic EL elements". More specifically, there are organic EL elements that are used as displays for civil and industrial use or as light sources for printing heads).

[Background technique]

An example of a conventional organic EL device is disclosed in Japanese Patent Laid-Open No. 7-78689. The disclosed organic EL device aims at achieving high luminous brightness, and is characterized in that, as shown in Fig. 20, the wavelength of the interference peak (A2) and the luminescence peak (B2) of light generated in the organic light-emitting layer ) Have the same wavelength. That is, the light trapped in the organic light-emitting layer passes through the laminated layers to produce a so-called interference effect, but the interference peak wavelength caused by the interference effect is the same as the emission peak wavelength of the light generated in the light-emitting layer .

However, if the interference peak wavelength caused by the interference effect is made to coincide with the emission peak wavelength of the generated light, on the contrary, the value of the color purity (CIE chromaticity coordinate) tends to decrease. For example, in the case of cyan light emission with a peak wavelength of 400 to 490nm, because it contains some highly visible green components, if the interference wavelength is consistent with the peak wavelength, the light intensity of the green component will also be enhanced. As a result, it was found that the value of color purity (CIE chromaticity coordinates) was reduced.

In addition, as shown in Figure 35, JP 7-240277 A discloses an organic EL element having a transparent electrode with high flexibility and a method in which the total optical film thickness of the organic light-emitting layer is set to a value capable of enhancing the center wavelength. .

However, in this organic EL element, it has also been found that when the value of the center wavelength is increased, the value of the intensity near the center wavelength will be increased at the same time, and the color purity will be reduced.

Of course, in these organic EL devices, although the thickness of the organic light-emitting layer is extremely uniform without thickness deviation, the value of the CIE chromaticity coordinate can be made uniform, but because the yield will be significantly reduced, it is not a practical solution. method.

Therefore, the inventors of the present invention have intensively studied the above problems and found that the CIE chromaticity coordinate value measured in accordance with JISZ8701 has a maximum value corresponding to the total optical path length of the transparent electrode and the organic layer. Therefore, if such a maximum value and a minimum value are considered to determine the thickness of the organic layer, and then the interference peak wavelength and the emission peak wavelength are shifted to a certain range, the change of the CIE chromaticity coordinate will be smaller. .

That is, the object of the present invention is to provide an organic EL device that can produce small changes in color purity (CIE chromaticity coordinates) even if the total optical path length of the transparent electrode and the organic layer has a certain distribution, and can effectively produce the organic EL device. EL element method.

[Disclosure of Invention]

[1] One aspect of the present invention is an EL element comprising an organic layer sandwiched between electrodes whose at least one is a transparent electrode, characterized in that when the total optical path length of the transparent electrode and the organic layer is set to t( nm), set the optical path length of the minimum value of CIEx chromaticity coordinates or CIEy chromaticity coordinates measured according to JIS Z8701 to Min(nm), and set the CIEx chromaticity coordinates or CIEy color measured according to JIS Z 8701 When the maximum optical path length of the degree coordinate is Max (nm), the total optical path length (t) will satisfy the following magnitude relationships (a) and (b), or any one of the magnitude relationships. Min-20nm<t<Min+20nm (a)Max-20nm<t<Max+20nm (b)

With this configuration, even if a predetermined film thickness distribution is generated in the organic layer, since the color purity (CIE chromaticity coordinate) is changed to a value near the optical path length representing a small maximum value or minimum value, it can be Obtain excellent color purity.

Here, for convenience, the units of the maximum optical path lengths Max and Min representing the total optical path length (t) of the transparent electrode and the organic layer, CIEx chromaticity coordinate or CIEy chromaticity coordinate may sometimes be omitted for convenience ( nm) record.

[2] In addition, when the organic EL element of the present invention is constituted, it is preferable that the total optical path length (t) of the transparent electrode and the organic layer is combined with the optical path length representing the minimum value of the CIEx chromaticity coordinate or the CIEy chromaticity coordinate Length (Min), or the optical path length (Max) indicating the maximum value of CIEx chromaticity coordinate or CIEy chromaticity coordinate is consistent.

With such a configuration, even if a predetermined film thickness distribution is generated in the organic layer, since the change in color purity (CIE chromaticity coordinates) adopts the optical path length representing a small maximum or minimum value, it is possible to obtain Excellent color purity.

[3] In addition, when the organic EL device of the present invention is constituted, it is preferable to set the emission peak wavelength (S1) of the organic layer in the range of 400 to 490 nm, and to set the total optical path length ( t1) is consistent with the optical path length (Min) representing the minimum value of the CIEy chromaticity coordinate.

With this structure, it can be used as an excellent organic EL device due to the blue hue (purity).

That is, in the case of blue light emission, in terms of hue changes, it is more affected by the CIEy chromaticity coordinate than the CIEx chromaticity coordinate. In addition, the reason for making the total optical path length (t1) coincide with the minimum value is that in the case of blue light emission, if it is made to coincide with the minimum value, the change in hue will be small.

[4] In addition, when the organic EL device of the present invention is constituted, it is preferable to set the emission peak wavelength (S2) of the organic layer to a value in the range of 580 to 700 nm, and to set the total optical path length of the transparent electrode and the organic layer at the same time (t2) is consistent with the optical path length (Max) representing the maximum value of the CIEx chromaticity coordinate or the optical path length (Min) representing the minimum value.

By making this structure, an excellent organic EL device can be made due to the purity of the blue color.

That is, in the case of red light emission, in terms of hue change, it is more affected by the CIEy chromaticity coordinate than the CIEy chromaticity coordinate. In addition, the reason for making the total optical path length (t2) coincide with the maximum value or the minimum value is that when red light is emitted, the change in hue becomes small in any case.

[5] In addition, when constituting the organic EL device of the present invention, it is preferable to set the emission peak wavelength (S3) of the organic layer to a value in the range of 500 to 570 nm, and to set the total optical path length of the transparent electrode and the organic layer at the same time (t3) is consistent with the optical path length (Max) representing the maximum value of the CIEy chromaticity coordinate.

By making it into a structure, it can be used as an excellent organic EL element due to the green hue (purity). That is, when green light is emitted, the change in hue is more affected by the CIEy chromaticity coordinate than the CIEx chromaticity coordinate. Also, the reason for making the total optical path length (t3) consistent with the maximum value Therefore, when green light is emitted, if it is consistent with the maximum value, the change in hue will be smaller.

[6] In addition, when constituting the organic EL device of the present invention, it is preferable that the in-plane distribution of the total optical path length (t) of the transparent electrode and the organic layer is within a range of ±20 nm.

By making the structure, the color purity (CIE chromaticity coordinate) change caused by the film thickness distribution in the transparent electrode or the organic layer can be alleviated and reduced. Accordingly, the value of the in-plane distribution within the range of ±20 nm means that the difference between the maximum and minimum optical path lengths in the plane measured by an ellipsometer is within 40 nm.

[7] In addition, when the organic EL device of the present invention is constituted, it is preferable to include an optical path length correction layer for adjusting the value of the total optical path length (t) of the transparent electrode and the organic layer.

With this configuration, it is easier to adjust the total optical path length of the transparent electrode and the organic layer. Even if a predetermined film thickness distribution in the organic layer is generated, the color purity (CIE chromaticity coordinate) can still be changed less.^。

[8] In another aspect of the organic EL device of the present invention, a blue light-emitting organic layer with a light emission peak wavelength of 400 to 490 nm is sandwiched between electrodes, at least one of which is a transparent electrode, and a green light emission with a light emission peak wavelength of 500 to 570 nm is interposed. An organic electroluminescence element composed of an organic layer and a red light-emitting organic layer with an emission peak wavelength of 580 to 700 nm, characterized in that the total optical path length of the transparent electrode and the blue light-emitting organic layer is set to t1, which is measured in accordance with JISZ8701 Represents the minimum value of the CIEy chromaticity coordinates when the optical path length is set to Min, it will meet the size relationship of Min-20nm<t1<Min+20nm, or

Taking the total optical path length of the transparent electrode and the green light-emitting organic layer as t3, and the maximum optical path length of the CIEy chromaticity coordinate measured in accordance with JIS Z 8701 as Max, it will satisfy the size of Max-20nm<t3<Max+20nm Relationship, or

Taking the total optical path length of the transparent electrode and the red light-emitting organic layer as t2, and the maximum optical path length of the CIEx chromaticity coordinate measured in accordance with JIS Z 8701 as Max, it will satisfy Max-20nm<t2<Max+20nm.

With this configuration, even if the organic layer produces a predetermined film thickness distribution, any change in the color purity (CIE chromaticity coordinates) of the three primary colors (red, blue, and green) can be reduced.

Therefore, even when the area of the organic layer in the organic EL element is enlarged, it is possible to perform color display with an excellent hue.

[9] In another aspect of the organic EL device of the present invention, at least one of the transparent electrodes is sandwiched between the electrodes with a blue light-emitting organic layer with an emission peak wavelength of 400 to 490 nm, and a green light emission with an emission peak wavelength of 500 to 570 nm. An organic EL element composed of an organic layer and a red light-emitting organic layer with a peak emission wavelength of 580 to 700 nm is characterized by:

The total optical path length of the transparent electrode and the blue light-emitting organic layer is set to T1, and the minimum optical path length of the CIEy chromaticity coordinate measured in accordance with JIS Z 8701 is set to Min, and Min-20nm<t1< The size relationship of Min+20nm,

Taking the total optical path length of the transparent electrode and the green light-emitting organic layer as t3, and setting the maximum optical path length of the CIEy chromaticity coordinate measured in accordance with JIS Z 8701 as Max, it will satisfy Max-20nm<t3<Max+20nm Size relationship, and

Taking the total optical path length of the transparent electrode and the red light-emitting organic layer as t2, and setting the maximum optical path length of the CIEy chromaticity coordinate measured in accordance with JIS Z 8701 as Max, it will satisfy Max-20nm<t2<Max+ The size relationship of 20nm.

With this configuration, even if a predetermined film thickness distribution is generated in the organic layer, the color purity (CIE chromaticity coordinates) changes of the three primary colors (red, cyan, and green) can be reduced respectively.

Therefore, even when the area of the organic layer in the organic EL element is enlarged, it is possible to perform color display with an excellent hue.

[10] When the organic EL element of the present invention is constituted, it is preferable to provide a color conversion medium on the light-emitting surface side (the side where the EL light is taken out).

With this configuration, even if one type of organic layer is used, a full-color display can be performed due to an appropriate combination of color conversion media.

Therefore, even when performing full-color display, the structure of the organic EL element can be simplified and the manufacturing is easy.

[11] In addition, another aspect of the present invention includes a method for manufacturing an EL element including an organic layer sandwiched between electrodes whose at least one is a transparent electrode, which is characterized by:

The total optical path length of the transparent electrode and the organic layer is set to t (nm), and the optical path length that represents the minimum value of the CIEx chromaticity coordinate or the CIEy chromaticity coordinate measured in accordance with JIS Z 8701 is set to Min (nm), When the optical path length that represents the maximum value of CIEx chromaticity coordinates or CIEy chromaticity coordinates measured in accordance with JIS Z 8701 is set to Max (nm), the total optical path length will satisfy the following relationship (a) and (b) ), or form the transparent electrode and the organic layer by the size relationship of either side Min-20nm<t<Min+20nm (a)Max-20nm<t<Max+20nm (b)

With this implementation, even if a predetermined film thickness distribution is generated in the organic layer, an organic EL device with a small change in color purity (CIE chromaticity coordinates) can still be effectively provided.

[12] In addition, when implementing the method of manufacturing an organic EL device of the present invention, it is preferable to form an organic layer on a previously formed transparent electrode to adjust the total optical path length.

With this implementation, a predetermined transparent electrode, such as a commercially available transparent electrode, can be used directly, and the total optical path length (t) can be adjusted by appropriately changing the thickness or tortuosity of the organic layer.

[13] Furthermore, when the method of manufacturing an organic EL element of the present invention is implemented, it is preferable to include a process of forming an optical path length correction layer for adjusting the value of the total optical path length of the transparent electrode and the organic layer.

With this implementation, the adjustment of the total optical path length of the transparent electrode and the organic layer will be easier. Even if a predetermined film thickness distribution is generated in the organic layer, it can still provide more effective organic color purity (CIE chromaticity coordinates) change. EL element.

[A brief description of the drawing]

Figure 1 is a cross-sectional view of the organic EL device of the first and second embodiments. Figure 2 shows the relationship between the total optical path length (t1) of the transparent electrode and the blue light-emitting organic layer and the CIEx chromaticity coordinate value of EL light emission. Figure 3 shows the relationship between the total optical path length (t1) of the transparent electrode and the blue light-emitting organic layer and the CIEy chromaticity coordinate value of EL light emission. Figure 4 shows the CIE chromaticity coordinate diagram of blue luminescence. Figure 5 shows the magnification of the CIE chromaticity coordinates of blue luminescence. Fig. 6 is a graph showing the relationship between the interference peak (A1) and the luminescence peak (B1) in the blue light-emitting organic layer of the first embodiment. Fig. 7 is a graph showing the relationship between the interference peak (A2) and the luminescence peak (B2) in the blue light-emitting organic layer of the conventional example. Figure 8 shows the relationship between the total optical path length (t3) of the transparent electrode and the green light-emitting organic layer and the CIEx chromaticity coordinate value of EL light emission. Figure 9 shows the relationship between the total optical path length (t3) of the transparent electrode and the green light-emitting organic layer and the CIEy chromaticity coordinate value of EL light emission. Figure 10 shows the CIE chromaticity coordinate diagram of luminescence. Figure 11 shows an enlarged view of the CIE chromaticity coordinates for green light emission. Fig. 12 is a graph showing the relationship between the interference peak (A1) and the luminescence peak (B1) in the green light-emitting organic layer of the second embodiment. Figure 13 is a graph showing the relationship between the interference peak (A2) and the luminescence peak (B2) in the green light-emitting organic layer of the conventional example. Fig. 14 is a cross-sectional view of the organic EL device in the third embodiment. Figure 15 shows the relationship between the total optical path length (t2) of the transparent electrode and the red light-emitting organic layer and the CIEx chromaticity coordinate value of EL light emission. Figure 16 shows the relationship between the total optical path length (t2) of the transparent electrode and the red light-emitting organic layer and the CIEy chromaticity coordinate value of EL light emission. Figure 17 shows the CIE chromaticity coordinate diagram for red luminescence. Figure 18 is an enlarged view of the CIE chromaticity coordinates of red luminescence. Fig. 19 is a graph showing the relationship between the interference peak (A1) and the luminescence peak (B1) in the red light-emitting organic layer of the third embodiment. Figure 20 is a graph showing the relationship between the interference peak (A2) and the luminescence peak (B2) in the red light-emitting organic layer of the conventional example. Fig. 21 is a cross-sectional view of the organic EL device in the fourth embodiment. Fig. 22 shows a diagram of the organic EL element of Example 7. Fig. 23 shows a diagram of the organic EL element of Example 8. Figure 24 is a diagram for comparing the relationship between the total optical path length and the CIEy chromaticity coordinate value of EL luminescence in Example 2 and Comparative Example 3. Figure 25 is used to compare the total optical path length in Example 3 and Comparative Example 4. The graph of the relationship between the chromaticity and the CIEx chromaticity coordinate value of EL luminescence. Figure 26 is a diagram for comparing the relationship between the total optical path length and the respective CIEy chromaticity coordinate values of EL luminescence in Example 1 and Comparative Examples 1 and 2. Figure 27 is a diagram for comparing the relationship between the total optical path length and the CIEy chromaticity coordinate values of EL luminescence in Examples 7 to 9 and Comparative Example 5. Figure 28 is a diagram showing the relationship between the total optical path length and the CIEx chromaticity coordinate values of EL luminescence in the case of combining GCCM in the first embodiment. Figure 29 is a diagram showing the relationship between the total optical path length and the respective CIEy chromaticity coordinate values of EL light emission in the case of combining GCCM in the first embodiment. Figure 30 is a diagram showing the relationship between the total optical path length and the CIEx chromaticity coordinate values of EL light emission in the case of combining RCCM in the first embodiment. Figure 31 is a diagram showing the relationship between the total optical path length and the CIEy chromaticity coordinate values of EL light emission in the case of combining RCCM in the first embodiment. Figure 32 shows the relationship between the case where the total optical path length (t1) of the transparent electrode and the blue light-emitting organic layer is longer and the CIEx chromaticity coordinate value of EL light emission. Figure 33 shows the relationship between the case where the total optical path length (t1) of the transparent electrode and the blue light-emitting organic layer is longer and the CIEy chromaticity coordinate value of EL light emission. Figure 34 shows a diagram of a vacuum deposition apparatus. Figure 35 is a graph showing the relationship between the interference peak wavelength (11) and the emission peak wavelength (12) of the conventional example. The relationship between the CIEx chromaticity coordinate values of EL luminescence. Figure 33 shows the relationship between the case where the total optical path length (t1) of the transparent electrode and the blue light-emitting organic layer is longer and the CIEy chromaticity coordinate value of EL light emission. Figure 34 shows a diagram of a vacuum deposition apparatus. Figure 35 is a graph showing the relationship between the interference peak wavelength (11) and the emission peak wavelength (12) of the conventional example. The relationship between the CIEx chromaticity coordinate values of EL luminescence. Figure 33 shows the relationship between the case where the total optical path length (t1) of the transparent electrode and the blue light-emitting organic layer is longer and the CIEy chromaticity coordinate value of EL light emission. Figure 34 shows a diagram of a vacuum deposition apparatus. Figure 35 is a graph showing the relationship between the interference peak wavelength (11) and the emission peak wavelength (12) of the conventional example.

[Symbol Description]

10 Transparent electrode layer (anode layer, ITO film) 11 interference peak wavelength 12 blue light-emitting organic layer (emission peak wavelength) 14 striped IZO pattern as anode (lower electrode) 16 first interlayer insulating film (cathode layer) 18 Two-layer insulating film 20 Cathode extraction part 22 Glass substrate 100 Organic EL element 201 Vacuum vapor deposition device 210 Vacuum tank 212A to 212E Vapor deposition source 212F Tungsten filament 221 Substrate clamp A1, A2 Interference peak B1, B2 Peak value S1 of emission spectrum Luminous peak wavelength

[The best mode for carrying out the invention]

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, the drawings referred to here schematically show the size, shape, and arrangement relationship of each component to the extent that the present invention can be understood. Therefore, the present invention is not limited to the illustrated examples. Also, on the drawing, the hatching showing the cross-section may be omitted.

<u style="single">The first embodiment</u>

The organic EL element 100 in the first embodiment is as shown in Fig. 1. It is composed of a transparent electrode layer (anode layer) 10 and a blue light emission peak wavelength (S1) of 100 to 490 nm, which are sequentially laminated on a glass substrate. Color light-emitting organic layer 12, and cathode layer 16. In the organic EL element of the first embodiment, when the total optical path length of the transparent electrode 10 and the blue light-emitting organic layer 12 is taken as t1, it represents the optical path length of the minimum value of the CIEy chromaticity coordinate measured in accordance with JIS Z 8701 As Min, it satisfies the size relationship of Min-20nm&lt;t1&lt;Min+20nm.

In addition, if an electron injection layer, an electron transport layer, a positive hole injection layer, a positive hole transport layer or other organic layers are provided in addition to the blue light-emitting organic layer 12, the optical path length of these layers is included in the blue It can be considered in the light-emitting organic layer.

The following describes the relationship between the total optical path length of the transparent electrode 10 and the blue light-emitting organic layer 12 (hereinafter sometimes referred to as the optical path length) and the minimum value of the CIE chromaticity coordinate with reference to FIGS. 2-7. In addition, the constituent elements of the organic EL element 100 shown in FIG. 1 will be specifically described.

(1) The relationship between the total optical path length of the transparent electrode and the blue light-emitting organic layer and the extreme value of the CIEy chromaticity coordinate.

Figure 2 shows the relationship between the total optical path length (t1) of the transparent electrode and the blue light-emitting organic layer and the CIEx chromaticity coordinate value of EL light emission. Take the value of the total optical path length (t1) on the horizontal axis, and take the CIEx chromaticity coordinate value on the vertical axis.

Fig. 3 is a diagram showing the relationship between the total optical path length (t1) of the transparent electrode and the blue light-emitting organic layer and the CIEy chromaticity coordinate value of EL light emission. Take the value of the total optical path length (t1) on the horizontal axis, and take the CIEy chromaticity coordinate axis on the vertical axis.

In addition, for reference purposes, Fig. 4 shows the CIE chromaticity coordinates (calculated values) of the light emitted from the blue light-emitting organic layer, and Fig. 5 shows an enlarged view thereof. Each horizontal axis represents the value of the CIEx chromaticity coordinate, and the vertical axis represents the value of the CIEy chromaticity coordinate. Generally, in the case of blue light emission, the value of the CIEx chromaticity coordinate is about 0.11 to 0.17, and the value of the CIEy chromaticity coordinate is about 0.07 to 0.29.

It can be seen from Fig. 2 and Fig. 3 that the CIEx chromaticity coordinate value and the CIEy chromaticity coordinate value change periodically with the change of the total optical path length of each transparent electrode and blue light-emitting organic layer.

Moreover, the CIEx chromaticity coordinate value has a minimum value (Min) and a maximum value (Max) in the total optical path length as follows. Minimum value (Min): 200nm, 470nm, 750nm, 970nm level Maximum value (Max): 90nm, 340nm, 600nm, 840nm level

In addition, the CIEy chromaticity coordinate value has a minimum value (Min) and a maximum value (Max) in the following total optical path length. Minimum value (Min): 190nm, 430nm, 670nm, 930nm level Maximum value (Max): 90nm, 340nm, 560nm, 810nm level

Furthermore, the smaller the deviation between the values of the CIEx chromaticity coordinates and the CIEy chromaticity coordinates, the smaller the color change in the blue light. However, in the case of blue luminescence, in human vision, those with a deviation of the CIEy chromaticity coordinate value than the CIEx chromaticity coordinate will experience a large change (strong change) in blue.

Therefore, even if there is a predetermined deviation in the total optical path length of the blue light-emitting organic layer, by obtaining the relationship with the minimum value (Min) or the maximum value (Max) of the CIEy chromaticity coordinate value, the CIEy of the hue may be affected. The change in the chromaticity coordinate value becomes smaller.

For example, if there is a deviation of ±20nm in the total optical path length, as shown by the symbol B1 in Figure 5, the total optical path length is made to be the minimum value (Min) or maximum value (Max) of the CIEy chromaticity coordinate value. If the relationship is 468nm, the CIEy chromaticity coordinate value will vary from 0.2280 to 0.2384, and the difference between the maximum value and the minimum value (b1) will become 0.0104.

On the other hand, even if the total optical path length has a deviation of ±20 nm, as shown by the symbol B2 in Figure 5, the relationship between the total optical path length and the minimum value (Min) of the CIEy chromaticity coordinate value is 430 nm, then The CIEy chromaticity coordinate value will vary from 0.2219 to 0.2228 and the difference (b2) between the maximum value and the minimum value will become 0.0009. That is, compared with the case where there is no relation, it is a low value of 9% or less (0.104×9/100%, calculated in the same way below).

In the same way, as shown by the symbol B3 in Figure 5, the relationship between the total optical path length (t1) and the maximum value (Max) of the CIEy chromaticity coordinate value is obtained as 560nm, then the CIEy chromaticity coordinate value will be 0.2834 Change within the range of 0.2848 and the difference (b3) between the maximum value and the minimum value becomes 0.0014. That is, it is a low value of 14% or less compared with the case of no acquisition relationship.

Here, the method of adjusting the total optical path length of the transparent electrode and the blue light-emitting organic layer to the minimum value (Min) or the maximum value (Max) of the CIE chromaticity coordinate value is not particularly limited. The tortuosity of the transparent electrode, the thickness of the transparent electrode, the tortuosity of the blue light-emitting organic layer, and the thickness of the blue light-emitting organic layer can be changed appropriately, or the optical path length compensation layer can be provided as in the fourth and fifth embodiments. Very ideal.

In addition, Fig. 6 is a graph showing the relationship between the interference peak and the emission spectrum in the case where blue light is emitted in the first embodiment. In Figure 6, the interference peak is represented by the symbol A1 and the emission spectrum is represented by the symbol B1. Also, in this example, the total optical path length (nm) of the transparent electrode and the blue light-emitting organic layer is set to 430 nm in relation to the minimum value (Min) of the CIEy chromaticity coordinate value. However, in order to clearly know the interference peak position, for convenience, the interference factor is normalized, and the maximum value is 100, and the minimum value is 0. On the other hand, the luminous intensity is not standardized and expressed in actual luminous intensity.

It can be seen from Fig. 6 that, in the first embodiment, the interference peak (wavelength: 431 nm) (A1) and the peak of the emission spectrum (wavelength: 468 nm) (B1) are shifted by about 37 nm in wavelength.

In contrast, FIG. 7 is a graph showing the interference peak and the relationship between the emission spectrum and the wavelength when the conventional organic EL element is made to emit blue light. In Fig. 7, in the same manner, the interference peak is indicated by the symbol A2, and the emission spectrum is indicated by the symbol B2. Also, in this conventional example, in order to make the interference peak (A2) coincide with the peak of the emission spectrum (B2), as shown by the symbol B1 in Figure 5, the total light of the transparent electrode and the blue light-emitting organic layer The path length (nm) is made 468nm. However, in the case of the total optical path length, the CIEy chromaticity coordinate value will not become a maximum value (Max) or a minimum value (Min).

Therefore, considering the relationship shown in Figures 2 and 3, even if the total optical path length of the transparent electrode and the blue light-emitting organic layer has a predetermined deviation, the interference peak (A1) and the luminescence peak are shifted, by The total optical path length is related to the maximum value (Max) or the minimum value (Min), preferably to the minimum value of the CIEy chromaticity coordinate value. In the organic EL element of the first embodiment, the CIE The chromaticity coordinate value will become smaller, and as a result, the visually perceived blue change will become smaller.

On the other hand, in the conventional organic EL element, even if the interference peak (A2) and the luminescence peak (B2) are already the same, the total optical path length of the transparent electrode and the blue light-emitting organic layer is not equal to the maximum value (Max) or extremely small. Because of the value (Min) acquisition relationship, the change in the CIE chromaticity coordinate value due to such a deviation in the total optical path length will increase, and as a result, the visually perceived blue change can be increased.

Furthermore, in the organic EL element of the first embodiment, although the interference peak (A1) and the emission peak (B1) of the blue light-emitting organic layer are shifted, the value of the EL luminous intensity will slightly decrease, but the value of the EL luminous intensity will be slightly lower than that of the interference peak ( A2) Compared with the case of the conventional organic EL device whose emission peak is the same, the reduction is only about 7%, so there is no problem in practical use.

In addition, it has been confirmed that as shown in Fig. 32 and Fig. 33, by making the thickness of the blue light-emitting organic layer a value of 2,000 nm or more, preferably a value of 3,000 nm or more, and more preferably a value of 5,000 nm or more . The fact that the change in the CIE chromaticity coordinate value due to the deviation of the total optical path length of the transparent electrode and the blue light-emitting organic layer can be made smaller. Therefore, if the application is to increase the thickness of the blue light-emitting organic layer, the blue light-emitting The thickness of the light-emitting organic layer is set to the above-mentioned value, and the recognizable color tone is better, and blue light emission is small.

Conversely, if the thickness of the blue light-emitting organic layer is less than 2,000 nm, as described above, the method of adjusting the total optical path length representing the maximum value (Max) or the minimum value (Min) of the CIEy chromaticity coordinate value It can be said to be an extremely effective method for recognizing blue light with good color tone and small blue change.

(2) Organic layer

The organic layer is composed of at least an organic light-emitting layer, but preferably optionally includes a positive hole injection layer, a positive hole transport layer, a positive hole barrier layer, an electron injection layer, an electron transport layer, an electron barrier layer, and the like. The constituent layers of the representative organic layer are described below.

(Organic light-emitting layer) In the first embodiment, a blue organic light-emitting material is included in the organic layer (organic light-emitting layer). Although such a blue organic light-emitting material is not limited, it is preferable to have, for example, the following three functions at the same time.

(a) Charge injection function: It can inject electrons from the cathode layer or the electron injection layer while injecting the positive holes from the anode or the positive hole injection layer when an electric field is applied.

(b) Transport function: The function of moving the injected holes and electrons by the force of the electric field.

(c) Light-emitting function: It provides a place where electrons and positive holes are recombined and makes these light-emitting functions.

Therefore, an organic light-emitting material having such a function can be exemplified by an aromatic ring compound having a styryl group. That is, the aromatic ring compound having a styryl group can provide excellent light-emitting characteristics and durability, which is preferable.

In addition, the organic compounds that can be used as the material of the light-emitting layer are not particularly limited, but examples include: benzoxazole-based, benzimidazole-based, benzoxazole-based fluorescent whitening agents, metal clamps, etc. Chelateoxinoide compounds, styrylbenzene compounds, etc.

Specific preferred compound names may be those disclosed in Japanese Patent Laid-Open No. 59-194393. Representative examples are: 2,5-bis(5,7-di-tertiary pentyl-2-benzoxazolyl)-1,3,4-diazole, 4,4'-bis[5, 7-bis(2-methyl-2-butyl)-2-benzoxazolyl) stilbene, 2,5-bis(5,7-di-tert-pentyl-2-benzoxazolyl) phene, 2,5-bis[5-α,α-dimethylphenyl-2-benzoxazolyl]phene, 2,5-bis[5,7-bis(2-methyl-2 -Butyl)-2-benzoxazolyl)-3,4-diphenyloxazolyl, 2,5-bis(5-methyl-2-benzoxazolyl)phene, 4,4' -Bis(2-benzoxazolyl)biphenyl, 5-methyl-2-[2-[4-(5-methyl-2-benzoxazolyl)phenyl]vinyl]benzoxa Azoles, 2-[2-(4-chlorophenyl)vinyl] benzoxazoles such as [1,2-α]oxazole, 2-2'-(p-phenylene diethylene Yl)-bisbenzoxazole and other benzoxazole series, 2-[2-[4-(2-benzimidazolyl)phenyl]vinyl]benzimidazole, 2-[2-(4- Carboxyphenyl) vinyl] benzimidazole and other benzimidazole fluorescent whitening agents. In addition, other useful compounds are listed in "Chemistry of Synthetic Dyeing", pages 628 to 637 and 640 in 1971.

In addition, as the above-mentioned clamp-type oxide compound, for example, the one disclosed in JP 63-295695 A can be used. The representative examples are: ginseng (8-qualine phenol) aluminum, bis (8-qualine phenol) magnesium, bis (benzo[f]-8- phenol) zinc, and bis (2- oxoline phenol ester) Alumina, ginseng (8-phenol) indium, ginseng (5-methyl-8-line phenol) aluminum, 8- lithium phenate, ginseng (5-chloro-8-phenol) gallium, double (5-Chloro-8-phenol)calcium, poly[zinc(II)-bis(8-hydroxy-5-phenolyl)methane] and other 8-hydroxylline metal complexes and dilithium Table Dilithium epindolidione and so on.

In addition, as the above-mentioned styrylbenzene-based compound, for example, those disclosed in the specifications of European Patent No. 0319881 and European Patent No. 0373582 can be used. The representative examples are: 1,4-bis(2-methylstyryl)benzene, 1,4-bis(3-methylstyryl)benzene, 1,4-bis(4-methylstyryl) )Benzene, stilbene benzene, 1,4-bis(2-ethylstyryl)benzene, 1,4-bis(3-ethylstyryl)benzene, 1,4-bis(2-methyl Styryl)-2-methylbenzene, 1,4-bis(2-methylstyryl)-2-ethylbenzene, etc. In addition, the stilbene derivatives disclosed in JP 2-252793 A can also be used as the material of the light-emitting layer. The representative examples are: 2,5-Double (4-A

Styryl), 2,5-bis(4-ethylstyryl), 2-5-bis[2-(1-yl)vinyl]pyridine, 2-5-bis (4-Methoxystyryl), 2,5-bis[2-(4-biphenyl)vinyl], 2,5-bis[2-(1-pyrenyl)vinyl ] etc. Others, for example, the polyphenyl compound disclosed in the specification of European Patent No. 0387715 can also be used.

Furthermore, other than the above-mentioned fluorescent whitening agents, metal-clamped oxide compounds, and styrylbenzene compounds, etc., it is possible to use, for example: 1,2- and phthaloperinone (Journal of Applied Physics No. 27 Volume, L713 (I988), 1,-4-Diphenyl-1,3-butadiene 1,1,4,4-tetraphenyl-1,3-butadiene (The above is Applied Physics Communications, Volume 56, L799 (1990)), naphthalenedimethimide derivatives (Japanese Patent Laid-open No. 2-305886), derivatives (Japanese Patent Laid-Open No. 2-189890), oxadiazole derivatives (Japanese Patent Laid-open No. 2-305886), 2-216791, or oxadiazole derivatives disclosed by Hamada et al. in the 38th Joint Lecture on Applied Physics Relations), aldehyde azide derivatives (Japanese Patent Laid-Open No. 2-220393), oxazole Morpholine derivatives (Japanese Patent Application Laid-Open No. 2-220394), cyclopentadiene derivatives (Japanese Patent Application Laid-Open No. 2-289675), Rhodole Derivatives (Japanese Patent Application Laid-Open No. 2-296891), Styrylamine derivatives (Applied Physics Communications, Vol. 56, L799 (1990)), Coumarin-based compounds (Japanese Patent Publication No. 2-191694), International Publication WO90/13148 and Applied Physics Lectures, Vol. 58, No. 18, The polymer compound described on page 1982 (1999) is used as the material of the light-emitting layer.

In the present invention, particularly as the material of the light-emitting layer, it is preferable to use an aromatic dimethine-based compound (disclosed in European Patent No. 0388768 and Japanese Patent Laid-Open No. 3-231970). Specific examples can include: 1,4-phenylene dimethyl sulfide, 4,4-phenyl dimethyl sulfide, 2,5-xylene dimethyl methine, 2,6-phenylene dimethyl sulfide, 1,4-phenylene dimethyl sulfide Xylylenedimethine, 1,4-p-extension methionine, 9,10 anthracenylmethionine, 4,4'-bis(2,2-di-tert-butylphenylvinyl) biphenyl, 4,4'-bis(2,2-diphenylvinyl)biphenyl, etc. and its derivatives.

In addition, it is not limited to the content of the blue organic light-emitting material used in the first embodiment, but is suitable for the green organic light-emitting material of the second embodiment and the red organic light-emitting material of the third embodiment described later. Only in the organic light-emitting layer It is also very good to use benzoxazole series, benzimidazole series, benzoxazole series and other fluorescent brighteners or metal complexes with styrylbenzene series compounds and 8-oxolinephenol derivatives as ligands. ideal.

Furthermore, the organic luminescent materials with the stilbene aryl extension skeleton, such as 4,4'-bis(2,2-diphenylvinyl) biphenyl, etc., are used as the main group, and the blue Strong fluorescent substances to red, such as coumarin series or fluorescent substances doped with the same main group are also very suitable.

In addition, the thickness of the organic light-emitting layer formed in this way can be appropriately selected in consideration of the optical path length, etc., but it is preferably a value generally in the range of 5 nm to 5 μm.

The reason is that when the film thickness of the organic light-emitting layer is less than 5nm, the luminous brightness or durability may be reduced. On the other hand, if the film thickness of the organic light-emitting layer exceeds 5μm, the value of the applied voltage may increase. possible.

Therefore, the film thickness of the organic light-emitting layer is preferably within a range of 10 nm to 3 μm, and more preferably within a range of 20 nm to 1 μm. In addition, the organic light-emitting layer may be a one-layer structure composed of one or a combination of two or more of the above-mentioned materials, or may be a multi-layer structure composed of multiple layers of the same composition or different compositions.

(Positive hole injection layer)

In addition, the material of the positive hole injection layer provided as necessary can be selected and used from conventional positive hole injection materials that are conventionally used as light-conducting materials or from well-known positive hole injection layers used as organic EL devices. The material of the positive hole injection layer has any one of positive hole injection or electron barrier properties, and can be either organic or inorganic.

Preferable specific examples include: triazole derivatives (refer to U.S. Patent No. 3,112,197, etc.), oxadiazole derivatives (refer to U.S. Patent No. 3,189,447, etc.), imidazole derivatives (refer to Japanese Patent Publication No. 37-16096, etc.) , Polyarylalkane derivatives (refer to US Patent No. 3,615,402 Specification, No. 3,820,989 Specification, No. 3,542,544 Specification, Japanese Patent Publication No. 45-555, 51-10983, JP 51-93224 , 55-17105 Bulletin, 56-4148 Bulletin, 55-108667 Bulletin, 55-156953 Bulletin, 56-36656 Bulletin, etc.), oxazoline derivatives and pyrazoline derivatives (refer to U.S. Patent No. 3,180,729 Specification, No. 4,278,746, Japanese Patent Laid-Open No. 55-88064, 55-88065, 49-105537, 55-51086, 56-80051, 56-88141, 57-45545, 54-112637, 5-74546, etc.), phenylenediamine derivatives (refer to U.S. Patent No. 3,615,404 Specification, Japanese Patent No. 51-10105, 46-3712 Gazette, 47-25336 gazette, JP 54-53435 gazette, 54-110536 gazette, 54-119925 gazette, etc.), arylamine derivatives (refer to U.S. Patent No. 3,567,450 Specification, No. 3,180,703 Specification , Specification No. 3,240,597, Specification No. 3,658,520, Specification No. 4,232,103, Specification No. 4,175,961, Specification No. 4,012,376, Japanese Patent Publication No. 49-35702, 39-27577, and Japanese Patent Application Publication No. 55-144250 , 56-119132 Bulletin, 56-22437 Bulletin, West German Patent No. 1,110,518 specification, etc.), amino-substituted phenylpropenyl benzene derivatives (refer to U.S. Patent No. 3,526,501 specification, etc.), oxazole derivatives (U.S. Patent 3,257,203), styrylanthracene derivatives (refer to Japanese Patent Application Publication No. 56-46234, etc.), ketone derivatives (refer to Japanese Patent Application Publication No. 54-110837, etc.), and derivatives (refer to Specification of US Patent No. 3,717,462, Japanese Patent No. 54-59143, 55-52063, 55-52064, 55-46760, 55-85495, 57-11350, 57- 148749, Japanese Patent Application Publication No. 2-311591, etc.), stilbene derivatives (refer to Japanese Patent Application Publication No. 61-210363, 61-228151, 61-14642, 61-72255, 62- 47646, 62-36674, 62-10652, 62-30255, 60-93445, 60-94462, 60-174749, 60-175052, etc.), silamine Alkyl derivatives (U.S. Patent No. 4,950,950), polysiloxane-based (Japanese Patent Laid-Open No. 2-204996), aniline copolymers (Japanese Patent Laid-Open No. 2-282263), and the media disclosed in Japanese Patent Laid-Open No. 1-211399 Electrical polymer oligomers (especially phenophene oligomers), etc.Specification No. 950), polysiloxane-based (Japanese Patent Laid-Open No. 2-204996), aniline copolymers (Japanese Patent Laid-Open No. 2-282263), and dielectric polymer oligomers disclosed in Japanese Patent Laid-Open No. 1-211399 (Especially phenophene oligomers) and so on.Specification No. 950), polysiloxane-based (Japanese Patent Laid-Open No. 2-204996), aniline copolymers (Japanese Patent Laid-Open No. 2-282263), and dielectric polymer oligomers disclosed in Japanese Patent Laid-Open No. 1-211399 (Especially phenene oligomers) and so on.

Although the above can be used as the material for the positive hole injection layer, it is better to use: line compounds (disclosed in JP 63-295695 A, etc.), aromatic tertiary amine compounds and styryl amine compounds (refer to U.S. Patent No. 4,127,412, Japanese Patent Laid-Open No. 53-27033, 54-58445, 54-149634, 54-64299, 55-79450, 55-144250, 56- 119132, 61-295558, 61-98353, 63-295695, etc.), especially aromatic tertiary amine compounds.

In addition, representative examples of compounds are: , 1,10,15,20-tetraphenyl-21H,23H-oxoline copper(II), 1,10,15,20-tetraphenyl-21H,23H-Zinc(II), 5,10,15,20-F(pentafluorophenyl)-2IH,23H- phylloline, silicon cyanine oxide, aluminum cyanine chloride, cyanine (metal-free), dilithium Cyanine, copper tetramethyl cyanine, copper cyanine, chromium cyanine, zinc cyanine, lead cyanine, titanium cyanine oxide, magnesium cyanine, copper octamethyl cyanine, etc.

In addition, representative examples of preferred aromatic tertiary amine compounds and styrylamine compounds include: N,N,N',N'-tetraphenyl-4,4'-diaminobenzene, N,N' -Diphenyl-N,N'-bis-(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine, 2,2-bis(4-di- P-tolylaminophenyl)propane, 1,1-bis(4-di-p-tolylaminophenyl)cyclohexane, N,N,N',N'-tetra-p-tolyl -4,4'-Diaminobenzene, 1,1-bis(4-Di-p-tolylaminophenyl)-4-phenylcyclohexane, bis(4-dimethylamino)-2 -Methylphenyl)phenylmethane, bis(4-di-p-tolylaminophenyl)phenylmethane, N,N'-diphenyl-N,N'-bis(4-methoxybenzene Group)-4,4'-diaminobiphenyl, N,N,N',N'-tetraphenyl-4,4'-diaminophenyl ether, 4,4'-bis(diaminophenyl) Bitetraphenyl, N,N,N-tris(p-tolyl)amine, 4-(di-p-tolylamino)-4-[4(di-p-tolylamino)styryl] Stilbene, 4-N,N-diphenylamino-(2-diphenylvinyl)benzene, 3-methoxy-4'-N,N-diphenylaminostilbene, N-phenyl Carbazole and so on. In addition, the aforementioned aromatic dimethyl methine-based compound shown as the material of the light-emitting layer can also be used as the material of the positive hole injection layer.

The thickness of the positive hole injection layer is not particularly limited, but it is preferably a value in the range of 5 nm to 5 μm. For this positive hole injection layer, it can be a one-layer structure selected from one or a combination of two or more of the above-mentioned materials, or a multi-layer structure composed of multiple layers of the same composition or different compositions.

(Electron injection layer)

In addition, the electron injection layer provided as necessary has only to have a function of transferring electrons injected from the cathode to the light-emitting layer, and its material can be arbitrarily selected from conventionally known compounds.

Specific examples of the constituent materials of the electron injection layer include: nitro-substituted ketone derivatives, anthracene dimethane disclosed in Japanese Patent Laid-Open Nos. 57-149259, 58-55450, 63-104061, etc. Derivatives and Polymer Prescripts. Heterocycles such as diphenylquinone derivatives, pyran dioxide derivatives, naphthalene dibenzoanthracene, etc. described in page 681 of Japan, Vol. 37, No. 3 (1988) Tetracarboxylic anhydride, formamide, Japanese Journal of Applied Physics, 27, L269 (1988), JP-A 60-69657, 61-143764, 61-148159, etc. as disclosed Physics, anthraquinone dimethane derivatives and anthrone derivatives disclosed in JP-A 61-225151, 61-233750, etc., in Applied Physics Communications 55, 15, 1489, and the aforementioned 38th Applied Physics The Joint Lecture on Relations includes the oxadiazole derivatives disclosed by Hamada et al., and a series of electron-transmitting compounds disclosed in Japanese Patent Laid-Open No. 59-194393. In addition, Japanese Patent Application Laid-Open No. 59-194393 discloses the use of the aforementioned transmission compound as a material for the light-emitting layer, but the inventors' research has revealed that it can also be used as a material for the electron injection layer.

In addition, the metal complexes of 8-oxolinephenol derivatives, specifically, ginseng (8-oxoline phenol) aluminum, ginseng (5,7-dichloro-8- phenol) aluminum, ginseng ( 5,7-dibromo-8-oxoline phenol) aluminum, ginseng (2-methyl-8-oxoline phenol) aluminum, etc., and the central metal of these metal complexes is composed of In, Mg, Cu, Sn, Metal complexes substituted with Zn, Ga or Pa are used as the material of the electron injection layer. Others, metal-free or metal-phosphonium cyanines, or those whose ends are substituted with alkyl groups, sulfo groups, etc. are also acceptable. In addition, the stilbene-based derivative exemplified as the material of the light-emitting layer can also be used as the material of the electron injection layer.

Here, the thickness of the electron injection layer is not particularly limited, but it is usually preferably a value in the range of 5 nm to 5 μm. The electron injection layer may be a one-layer structure composed of one or a combination of two or more materials selected from the above-mentioned materials, or a multi-layer structure composed of multiple layers of the same composition or different compositions.

Furthermore, the film thickness of the electron injection layer is not particularly limited, and can be appropriately selected according to the situation, but it is preferably a value in the range of 5 nm to 5 μm. The reason is that if the thickness of the electron injection layer is less than 5nm, the luminous brightness or durability may decrease. On the other hand, if the thickness of the electron injection layer exceeds 5μm, the value of the applied voltage may increase. The situation. Therefore, it is preferable to set the film thickness of the electron injection layer to a value in the range of 10 nm to 3 μm, and more preferably to a value in the range of 20 nm to 1 μm.

(3) Electrode (anode layer)

For the sake of good positive hole injection, the anode layer preferably uses a metal, alloy, electrically conductive compound, or a mixture of these with a relatively large work function (for example, 40 eV or more). Specifically, indium tin oxide (ITO), CuI (copper iodide), SnO₂(Tin oxide), zinc oxide, gold, platinum, palladium, etc. are used singly or in combination of two or more.

In addition, the thickness of the anode layer is not particularly limited, but it is preferably a value in the range of 10 to 1,000 nm, and more preferably a value in the range of 10 to 200 nm.

(Cathode layer)

On the other hand, in order to have good electron injection properties, it is preferable to use a metal, alloy, electrically conductive compound, or a mixture of these with a small work function (for example, 4.0 eV or less) for the cathode layer. Specifically, magnesium, aluminum, indium, lithium, sodium, silver, and the like can be used alone or in combination of two or more.

In addition, the thickness of the cathode layer is not particularly limited, but it is preferably a value in the range of 10 to 1,000 nm, and more preferably a value in the range of 10 to 200 nm. In addition, in order to transmit light to the outside, at least one of the anode or the cathode must be made transparent.

(4) Support substrate

The explanation will be given on the supporting substrate in the organic EL device. If the supporting substrate has excellent mechanical strength and low moisture and oxygen permeability, it can be used as it is commonly used in such organic EL devices. Specifically, glass or ceramics can be exemplified.

(5) Configuration example The organic EL device of the first embodiment is made into the following configuration example , but other components, such as a combination of a hole injection layer and an electron injection layer, are also made into the following configuration examples to ideal. Here, in the configurations to , the substrate may not be provided under the anode layer but under the cathode layer.

Substrate/anode layer/organic light-emitting layer/cathode layersubstrate/anode layer/positive hole injection layer/organic light-emitting layer/cathode layersubstrate/anode layer/organic light-emitting layer/electron injection layer/cathode layersubstrate/anode layer /Positive hole injection layer/Organic light emitting layer/Electron injection layer/Cathode layer

In addition, in the organic EL element of the first embodiment, it is also desirable to provide a color conversion layer on the light-emitting surface side to achieve full-color display. Figure 28 shows the relationship between the total optical path length and CIEx chromaticity coordinates of the green conversion layer (sometimes referred to as GCCM (Green Color Changing Medium)) when the green conversion layer is provided on the light-emitting surface side. Figure 29 shows the relationship between the total optical path length including the green conversion layer and the CIEy chromaticity coordinates.

In addition, Figure 30 shows the relationship between the total optical path length and CIEx chromaticity coordinates of the red conversion layer (sometimes referred to as RCCM (Red Color Changing Medium)) when the red conversion layer is provided on the light-emitting surface side. Figure 31 shows the relationship between the total optical path length including the red conversion layer and the CIEy chromaticity coordinates.

<u style="single">Second embodiment</u>

The organic EL element in the second embodiment is basically different from the target structure of the first embodiment shown in FIG. 1, but differs from the point where the emission peak wavelength (S3) uses a green light-emitting organic layer of 500 to 570 nm. In addition, in the organic EL element of the second embodiment, the total optical path length of the transparent electrode and the green light-emitting organic layer is defined as t3, and the optical path length representing the maximum value of the CIEy chromaticity coordinate measured in accordance with JIS Z870I is Max. The size relationship of Max-20nm&lt;t3&lt;Max+20nm.

The main description of the green light-emitting organic layer is as follows, and the description of other constituent elements is appropriately omitted.

Figure 8 is a graph showing the relationship between the total optical path length (t3) of the transparent electrode and the green light-emitting organic layer and the CIEx chromaticity coordinate value of EL light emission. The horizontal axis takes the value (nm) of the total optical path length (t3) and the vertical axis takes the CIEx chromaticity coordinate value to indicate it.

In addition, FIG. 9 is a diagram showing the relationship between the total optical path length (t3) of the transparent electrode and the green light-emitting organic layer and the CIEy chromaticity coordinate value of EL light emission. The horizontal axis takes the value (nm) of the total optical path length (t3) and the vertical axis takes the CIEy chromaticity coordinate value to indicate it.

In addition, for reference, Fig. 10 shows the CIE chromaticity coordinates (calculated values) of the emission from the green light-emitting organic layer, and Fig. 11 shows an enlarged view thereof. Each horizontal axis represents the CIEx chromaticity coordinate value and the vertical axis represents the CIEy chromaticity coordinate value. Generally, in the case of green light emission, the CIEx chromaticity coordinate value is 0.15 to 0.33 degree, and the CIEy chromaticity coordinate value is 0.60 to 0.75 degree.

It can be seen from Fig. 8 and Fig. 9 that the CIEx chromaticity coordinate value and the CIEy chromaticity scale value respectively change periodically as the total optical path length of the transparent electrode and the green light-emitting organic layer changes.

In addition, the CIEx chromaticity coordinate value has a minimum value (Min) and a maximum value (Max) in the total optical path length as follows. Minimum value (Min): 200nm, 470nm, 745nm degree Maximum value (Max): 100nm, 360nm, 630nm, 910nm degree and, in terms of CIEy chromaticity coordinate value, it has a minimum value (Min) in the following total optical path length And the maximum value (Max). Minimum value (Min): 100nm, 360nm, 640nm, 9I0nm degree Maximum value (Max): 220nm, 500nm, 770nm degree

Furthermore, if the deviation of the CIEx chromaticity coordinate and the CIEy chromaticity coordinate value is smaller, it means that the color change during the green light emission will be smaller. However, in the case of green luminescence, the discernibility of the CIEy chromaticity scale will be greater than that of the CIEx chromaticity scale for the recognition by human eyes, and the characteristic of distinguishing green variation is large.

Therefore, even if there is a certain degree of deviation in the total optical path length of the transparent electrode and the green light-emitting organic layer, the minimum value (Min) or the maximum value (Max) of the total optical path length and the CIEy chromaticity coordinate value can be obtained by Obtain the relationship so that the change in the CIEy chromaticity coordinate value that will affect the hue is smaller.

For example, if the total optical path length of the transparent electrode and the green light-emitting organic layer has a deviation of ±20nm, as shown by the symbol G1 in Figure 11, make the total optical path length the minimum value of the CIEy chromaticity coordinate value (Min) or the maximum value (Max) is irrelevant to 517nm, then the CIEy chromaticity coordinate value will change in the range of 0.6482 to 0.6502, and the difference between the maximum value and the minimum value will become 0.0020.

In contrast, even if there is a deviation of ±20 nm in the total optical path length of the transparent electrode and the green light-emitting organic layer, as shown by the symbol G2 in Figure 11, the total optical path length (t3) is made to be the same as the CIEy The maximum value (Max) of the chromaticity coordinate value is 497 nm, and the CIEy chromaticity coordinate value will vary from 0.6502 to 0.6505, and the difference between the maximum value and the minimum value will become 0.0002. That is, compared with the case where the maximum value (Max) is not related, it becomes a low value of 10% or less.

Similarly, even if the total optical path length of the transparent electrode and the green light-emitting organic layer has a deviation of ±20 nm, as shown by the symbol G3 in Figure 11, the total optical path length (t3) is regarded as the CIEy chromaticity coordinate The minimum value (Min) of the relationship is 645nm, then the CIEy chromaticity coordinate value will vary within the range of 0.6239 to 0.6243, and the difference between the maximum value and the minimum value will become 0.0004. That is, compared with the case where the minimum value (Min) is not related, it becomes a low value of 20% or less.

In addition, Fig. 12 is a graph showing the relationship between the interference peak value and the emission spectrum during green light emission in the second embodiment. In Figure 12, the interference peak is represented by the symbol A1, and the emission spectrum is represented by the symbol B1. Also, in this example, the total optical path length (nm) of the transparent electrode and the green light-emitting organic layer is 497 nm, which is related to the maximum value (Max) of the CIEy chromaticity coordinate value. However, in order to make the interference peak position clear, it is convenient to normalize the interference factor, and the maximum value is 100, and the minimum value is 0. On the other hand, the luminous intensity is not standardized and expressed in terms of actual luminous intensity.

It can be seen from Fig. 12 that in the second embodiment, the interference peak (wavelength 500 nm) (A1) and the peak of the emission spectrum (wavelength 520 nm) (B1) are shifted by about 20 nm in wavelength.

On the other hand, Fig. 13 is a graph showing the relationship between the interference peak and the emission spectrum and the wavelength during the green light emission in the conventional organic EL element. In Figure 13, the interference peak is also represented by the symbol A2, and the emission spectrum is represented by the symbol B2. Also, in this conventional example, in order to make the interference peak (A2) coincide with the peak of the emission spectrum (B2), as shown by the symbol G1 in Figure 11, the total optical path length of the transparent electrode and the green light-emitting organic layer The length (nm) is made 517 nm. However, in the case of the total optical path length, the CIEy chromaticity coordinate value will not become the maximum value (Max) or the minimum value (Min).

Therefore, considering the relationship shown in Figures 8 and 9, the total optical path length of the transparent electrode and the green light-emitting organic layer has a certain degree of deviation, even if the interference peak (A1) and the luminescence peak (B1) shift, borrow The relationship between the total optical path length and the maximum value (Max) or the minimum value (Min) is preferably obtained by obtaining the relationship with the maximum value of the CIEy chromaticity coordinate value. In the organic EL device of the second embodiment, The change of the CIEy chromaticity coordinate value will become smaller, that is, the color change will become smaller.

On the other hand, in the conventional organic EL device, even if the interference peak (A2) and the emission peak (B2) are the same, the total optical path length of the transparent electrode and the green light-emitting organic layer is not equal to the maximum value (Max) or Because the minimum value (Min) is obtained, the change in the CIEy chromaticity coordinate value due to the deviation of the total optical path length will become larger, and as a result, the visual green change will become larger.

In addition, in the organic EL device of the second embodiment, since the interference peak (A1) and the emission peak (B1) of the green light-emitting organic layer are shifted, the value of the EL luminescence intensity will be slightly reduced, but the interference peak (A2) and the interference peak (A2) and Compared with the conventional organic EL device with the same emission peak (B2), it is only about 2%

It is reduced, so there is no problem in practical use.

<u style="single">Embodiment 3</u>

In the organic EL element 116 in the third embodiment, as shown in FIG. 14, between the transparent electrode layer (anode layer) 10 and the cathode layer 12, a blue light-emitting organic layer 30 with a peak emission wavelength of 100 to 490 nm is sandwiched between the transparent electrode layer (anode layer) 10 and the cathode layer 12. The green light-emitting organic layer 32 with an emission peak wavelength of 500 to 570 nm and the red light-emitting organic layer 34 with an emission peak wavelength of 580 to 700 nm are formed on the glass substrate 22.

In the organic EL element 116 in the third embodiment, the total optical path length of the transparent electrode layer 10 and the blue light-emitting organic layer 30 is taken as t1, and the minimum value representing the CIEy chromaticity coordinate measured in accordance with JIS Z 8701 When the total optical path length of is taken as Min, it can satisfy the size relationship of Min-20nm&lt;t1&lt;Min+20nm.

Moreover, when the total optical path length of the transparent electrode layer 10 and the green light-emitting organic layer 32 is taken as t3, and the total optical path length representing the maximum value of the CIEy chromaticity coordinate measured in accordance with JIS Z 8701 is taken as Max, it can satisfy Max -20nm&lt;t3&lt;Max+20nm relationship.

Furthermore, when the total optical path length of the transparent electrode layer 10 and the red light-emitting organic layer 34 is taken as t2, and the total optical path length representing the maximum value of the CIEx chromaticity coordinate measured in accordance with JIS Z 8701 is taken as Max, it can satisfy The relationship between Max-20nm&lt;t2&lt;Max+20nm.

Therefore, in the third embodiment, not only the blue light-emitting organic layer 30 with the emission peak wavelength of 400 to 490 nm but also the green light-emitting organic layer 32 with the emission peak wavelength of 500 to 570 nm are held between the electrodes as an organic layer. And, except for the red light-emitting organic layer 34 having an emission peak wavelength of 580 to 700 nm, it has the same configuration as the organic EL element of the first embodiment.

In addition, the organic EL element composed of a green light-emitting organic layer with a peak emission wavelength of 500 to 570 nm sandwiched between electrodes is as described in the second embodiment.

Therefore, in the following description of the third embodiment, the red light-emitting organic layer 34 having an emission peak wavelength of 580 to 700 nm will be mainly described, and the description of other constituent elements will be omitted as appropriate.

Figure 15 is a diagram showing the relationship between the total optical path length (t2) of the transparent electrode and the red light-emitting organic layer and the CIEx chromaticity coordinate value of EL light emission. The horizontal axis represents the value (nm) of the total optical path length (t2), and the vertical axis represents the CIEx chromaticity coordinate value.

In addition, FIG. 16 is a diagram showing the relationship between the total optical path length (t2) of the transparent electrode and the red light-emitting organic layer and the CIEy chromaticity coordinate value of EL light emission. The horizontal axis represents the value (nm) of the total optical path length (t2), and the vertical axis represents the CIEy chromaticity coordinate value.

In addition, for reference, FIG. 17 shows the CIE chromaticity coordinates (calculated values) of the light emitted from the red light-emitting organic layer, and FIG. 18 shows an enlarged view thereof. Each horizontal axis represents the CIEx chromaticity coordinate value, and the vertical axis represents the CIEy chromaticity coordinate value. Generally, in the case of red light emission, the CIEx chromaticity coordinate value is 0.60 to 0.70 degree and the CIEy chromaticity coordinate value is 0.30 to 0.38 degree.

From Fig. 15 and Fig. 16, it can be seen that the CIEx chromaticity coordinate value and CIEy chromaticity coordinate value change periodically as the total optical path length of each transparent electrode and the green light-emitting organic layer changes.

In addition, the CIEx chromaticity coordinate value has a minimum value (Min) and a maximum value (Max) in the total optical path length as follows. Minimum value (Min): 230nm, 350nm, 820nm degree Maximum value (Max): 100nm, 390nm, 680nm, 980nm degree In addition, the CIEy chromaticity coordinate value has a minimum value (Min) and a maximum value in the total optical path length as follows (Max),

Minimum value (Min): 100nm, 390nm, 690nm, 980nm degree Maximum value (Max): 230nm, 520nm, 820nm degree Furthermore, if the deviation of CIEx chromaticity coordinate and CIEy chromaticity coordinate value is smaller, the red luminescence The color change will become smaller. However, in the case of red luminescence, the deviation of the CIEx chromaticity coordinate value is compared with the deviation of the CIEy chromaticity coordinate in the recognition of the human eye, which has the characteristic of recognizing the red change will be greater. Therefore, even if the total optical path length of the transparent electrode and the red light-emitting organic layer has a certain degree of deviation, it can be more affected by obtaining the relationship between the minimum value (Min) or the maximum value (Max) of the CIEx chromaticity coordinate value The change in the CIEx chromaticity coordinate value of the hue becomes smaller.

For example, there is a deviation of ±20nm in the total optical path length where the transparent electrode and red light have a chance, as shown by the symbol R1 in Figure 18. If the total optical path length (t2) is taken as the CIEx chromaticity coordinate If the minimum value (Min) or maximum value (Max) of the value is irrelevant at 596nm, the CIEx chromaticity coordinate value will vary within the range of 0.6231 to 0.6247 and the difference between the maximum value and the minimum value will become 0.0016.

In contrast, even if the total optical path length (t2) of the transparent electrode and the red light-emitting organic layer has a deviation of ±20nm, as indicated by the symbol R2 in the 18th circle, the optical path length (t2) and the CIEx chromaticity The minimum value (Min) of the coordinate value is obtained in relation to 523nm, then the CIEx chromaticity coordinate value will vary within the range of 0.6202 to 0.6203, and the difference between the maximum value and the minimum value will become 0.0001. That is, compared with the case where the minimum value (Min) is not related, it becomes a low value of 7% or less.

Similarly, if Figure 18 is indicated by the symbol R3, for example, the total optical path length (t2) of the transparent electrode and the red light-emitting organic layer and the maximum value (Max) of the CIEy chromaticity coordinate are obtained in relation to 688nm, then the CIEx chromaticity coordinate The value will vary from 0.6295 to 0.6296 and the difference between the maximum value and the minimum value will become 0.0001. That is, compared with the case where the maximum value (Max) is not related, it becomes a low value of 7% or less.

In addition, Fig. 19 is a graph showing the relationship between the interference peak and the emission spectrum when red emission is performed in the third embodiment. In Figure 19, the interference peak is represented by the symbol A1, and the emission spectrum is represented by the symbol B1. Also, in this example, the total optical path length (nm) of the transparent electrode and the red light-emitting organic layer is related to the maximum value (Max) of the CIEx chromaticity coordinate value at 680 nm. However, in order to make the interference peak position clear, it is convenient for the interference factor system to be normalized, and the normalized maximum is 100, and the minimum is 0. On the other hand, the luminous intensity is not standardized and expressed in terms of actual luminous intensity.

It can be seen from Fig. 19 that in the red light-emitting organic layer of the third embodiment, the interference peak (wavelength 697nm) (A1) and the peak of the emission spectrum (wavelength 600nm) (B1) are shifted by about 97nm in wavelength.

In contrast, Fig. 20 is a graph showing the relationship between the interference peak and the emission spectrum and the wavelength of the red emission in the conventional organic EL device. In Fig. 20, the interference peaks are also represented by the symbol A2, the emission spectrum and the symbol B2. Also, in this conventional example, in order to make the interference peak (A2) coincide with the peak of the emission spectrum (B2), it is indicated by the symbol R1 in Figure 18, which is the total light of the transparent electrode and the red light-emitting organic layer. The path length (nm) has nothing to do with the maximum value (Max) or the minimum value (Min) of 596nm.

Therefore, considering the relationship shown in Fig. 15 and Fig. 16, even if the total optical path length of the transparent electrode and the red light-emitting organic layer deviates to a certain extent, the interference peak (A1) and the luminescence peak (B1) are shifted from each other. , By obtaining the relationship between the total optical path length and the maximum value (Max) or minimum value, preferably by obtaining the relationship between the minimum value (Min) or the maximum value (Max) of the CIEx chromaticity coordinate value, and in the first The red light-emitting organic layer of the organic EL device of the third embodiment can reduce the color change.

On the other hand, in conventional organic EL devices, even if the interference peak (A2) and the luminescence peak (B2) coincide with each other, the total optical path length of the transparent electrode and the red light-emitting organic layer and the maximum value (Max) or the minimum value (Min ) It is irrelevant, the CIEx chromaticity coordinate value change due to the deviation of the total optical path length will become larger, and as a result, the visual red change will become larger.

In addition, in the organic EL device of the third embodiment, as the interference peak (A1) and the luminescence peak of the red light-emitting organic layer are shifted from each other, the value of EL luminescence intensity will slightly decrease, but the difference between the interference peak (A2) and the luminescence peak (B2) Compared with the conventional organic EL device, there is a reduction of about 20%, and there is no problem in practical use.

<u style="single">Fourth embodiment</u>

The organic EL element 120 in the fourth embodiment, as shown in FIG. 21, is laminated on a glass substrate 22 in order to form an optical path length correction layer 20, a transparent electrode layer (anode layer) 10, and a peak emission wavelength ( S1) is the blue light-emitting organic layer 12 and the cathode layer 16 of 400 to 490 nm. In addition, the organic EL element 120 of the fourth embodiment is represented by the total optical path length of the transparent electrode 10, the blue light-emitting organic layer 12, and the optical path length correction layer 20 as t4, which is measured in accordance with JIS Z 8701 When the optical path length of the minimum value of the CIEy chromaticity coordinate is taken as Min, it will satisfy the size relationship of Min-20nm&lt;t4&lt;Min+20nm.

That is, in the fourth embodiment, the optical path length correction layer 20 is provided between the transparent electrode layer (yangming layer) 10 and the blue light-emitting organic layer 12, and the total optical path length is set to a value within a predetermined range. , Has the same structure as the organic EL element of the first embodiment.

Therefore, the description will focus on the optical path length correction layer 20, and the description of other components will be omitted as appropriate.

Here, the transparent electrode is not limited to the anode layer, and the cathode layer may be a transparent electrode, or both the anode layer and the cathode layer may be transparent electrodes. However, when both the anode layer and the cathode layer are transparent electrodes, the optical path lengths of both the anode layer and the cathode layer are added together as the total optical path length.

(1) Optical path length correction method by optical path length correction layer With reference to Figs. 2 to 7, the optical path length correction method by the optical path length correction layer will be described. Fig. 7 is a graph showing the relationship between the interference factor and the emission spectrum and the wavelength (nm) from the blue light-emitting organic layer in the conventional organic EL device as described above. In the example in Figure 7, the total optical path length (t3) of the transparent electrode and the blue light-emitting organic layer is set to 468nm. From Figures 2 and 3, it can be seen that the total optical path length is related to CIEx chromaticity coordinates. Value or the maximum value (Max) or minimum value (Min) of the CIEy chromaticity coordinate value is irrelevant.

Therefore, the total optical path length (t1) of the transparent electrode and the blue light-emitting organic layer that coincides with the CIEx chromaticity coordinate value or the CIEy chromaticity coordinate value, such as the minimum value (Min), will be selected from the second and third diagrams.

Here, at this time, in Fig. 2 and Fig. 3, since 3 to 4 minimum values (Min) are shown respectively, the total optical path length (t1) showing any minimum value (Min) can be selected. However, it is better to select the CIEx chromaticity coordinate value near the minimum value (Min) or the minimum value (Min) with a small change in the CIEy chromaticity coordinate value. By selecting such a minimum value (Min), the change in the CIEx chromaticity coordinate value or the CIEy chromaticity coordinate value caused by the change in the total optical path length can be further reduced.

Therefore, the total optical path length of the transparent electrode and the blue light-emitting organic layer in the conventional organic EL element is compared with the transparent electrode and the blue electrode corresponding to the minimum value (Min) of the selected CIEx chromaticity coordinate value or CIEy chromaticity coordinate value. The difference between the total optical path length (t1) of the color light-emitting organic layer will be the optical path length of the optical path length correction layer.

Therefore, the thickness and constituent material of the optical path length correction layer can be selected in such a way that the optical path length to be corrected can be added. In this case, in order to be consistent with the optical path length 670nm corresponding to one of the minimum values (Min) of the CIEy chromaticity coordinate value, the transparent electrode and the blue light-emitting organic before the optical path length correction layer are deducted from 670nm The total optical path length (nm) of the layers is 468 nm, and an optical path length correction layer with an optical path length of 202 nm will be provided. Furthermore, by using the optical path length correction layer, it is possible to avoid the thickening of the organic matter between the electrodes for optical correction, and has the advantage of avoiding the increase in voltage when the organic layer is thickened.

(2) Constituent materials

The constituent material of the optical path length correction layer is not particularly limited, and inorganic or organic materials can be used. Examples of inorganic substances: glass, quartz, tin oxide, indium oxide, lead oxide, aluminum oxide, lithium oxide and other oxides, lithium fluoride, calcium fluoride, magnesium fluoride and other fluorides, gold, silver, copper, aluminum Metals such as, molybdenum can be used because they are transparent when they are thin. The above can be used alone or in combination of two or more.

In addition, the organic matter may include one or more of organic EL materials, polypropylene resins, polyethylene resins, fluorine resins, acrylic resins, polyether sulfonic acid resins, polycarbonate resins, etc. combination. If it is between the electrodes, it must be a way for electric charges to pass, and if it is placed outside the electrode, it can be a complete insulator.

In addition, since the optical path length is determined by the film thickness and the tortuosity, it is preferable to set the tortuosity of the constituent material to a value in the range of 1.0 to 3.0 (at a temperature of 25°C, measured by Abbe's refractometer). The reason is that it is difficult to obtain constituent materials for substances with a tortuosity rate of 1.0 or less. On the other hand, for constituent materials with a tortuosity rate of more than 3.0, the selection range of the constituent materials that can be used will be quite limited.

Therefore, the tortuosity of the constituent material is preferably set to a value in the range of 1.3 to 2.5, and more preferably set to a value in the range of 1.7 to 2.1.

(3) Thickness

The thickness of the optical path length correction layer is also not particularly limited, but it is preferably, for example, a value in the range of 1 to 2,000 nm. The reason is that, if the thickness of the optical path length correction layer is 1 nm or less, it is difficult to form a uniform thickness, or the obtained optical path length correction effect is relatively poor. On the other hand, if the thickness of the optical path length correction layer exceeds 2,000 nm, it is difficult to control the unevenness of the film thickness of the optical path length correction layer. In some cases, the total optical path length of the transparent electrode layer and the light-emitting organic layer may be adjusted instead. Difficulties occur.

Therefore, the thickness of the optical path length correction layer is preferably set to a value in the range of 2 to 500 nm, and more preferably set to a value in the range of 5 to 100 nm.

(4) Formation method

The method of forming the optical path length correction layer is not particularly limited, but it is preferable to use, for example, a vacuum evaporation method, a sputtering method, an electron beam (EB. Electron Beam) method, an MBE (Molecular Beam Epitaxy, molecular beam epitaxy) method, LB (Langumuir-Bladgett) method, CVD (Chemical Vapor Deposition) method, spin coating method, casting method.

(5) Configuration example

The organic EL element 120 of the fourth embodiment, as shown in FIG. 21, is a configuration example in which the optical path length correction layer 20 is provided between the substrate and the transparent electrode layer (anode layer) 10, but with other components For example, the positive hole injection layer or the electron injection layer may be combined to form the following configuration examples to . In particular, the configuration examples and to where the optical path length correction layer is provided between the substrate and the anode layer do not need to change the configuration of the organic EL element (anode layer/organic light-emitting layer/cathode layer) that has been proven in the past. it is good. Here, the substrate is not limited to the substrate of the anode but may be the substrate of the cathode. Furthermore, it is possible to provide not only one optical path length correction layer, but also two or more layers as in the configuration example . Substrate/optical path length correction layer/anode layer/organic light-emitting layer/cathode layersubstrate/cathode layer/optical path correction layer/organic light-emitting layer/cathode layersubstrate/anode layer/organic light-emitting layer/optical path length correction layer /Cathode layerSubstrate/Optical path length correction layer/Anode layer/Optical path length correction layer/Organic light emitting layer/Cathode layerSubstrate/Optical path length correction layer/Anode layer/Positive hole injection layer/Organic light emitting layer/Cathode layer Substrate/Optical Path Length Correction Layer/Anode Layer/Organic Light-Emitting Layer/Electron Injection Layer/Cathode Layer

Fifth embodiment

The fifth embodiment is the manufacturing method of the organic EL element 120 in the fourth embodiment. When the total optical path length of the transparent electrode, the organic layer, and the optical path length correction layer is defined as t (nm), it will be measured in accordance with JIS Z 8701 The optical path length representing the minimum value of the CIEx chromaticity coordinate or the CIEy chromaticity coordinate is taken as Min(nm), and the optical path length representing the maximum value of the CIEx chromaticity or the CIEy chromaticity coordinate measured in accordance with JIS Z 8701 is taken as the Max( nm), the total optical path length (t) can satisfy the following magnitude relationships (a) and (b) or any one of the magnitude relationships, including the process of forming a transparent electrode, an organic layer, and an optical path length correction layer.<maths><img file="TW463528B_D0001.tif" /></maths>

Therefore, in the manufacturing method of the fifth embodiment, it is preferable to sequentially include: a process of preparing a substrate, a process of forming an optical path length correction layer, a process of forming an anode layer (transparent electrode), a process of forming an organic light-emitting layer, and The process of forming the cathode layer.

Here, during the formation of the anode layer (transparent electrode), a substrate for forming a transparent electrode with a predetermined thickness from a predetermined material can also be prepared in advance and used directly.

Here, the process of forming the optical path length correction layer, which is the characteristic of the fifth embodiment, can be implemented after determining the thickness and constituent materials of the optical path length correction layer as described in the fourth embodiment. Then, an optical path length correction layer is formed on the substrate. The formation method at this time is preferably as described in the fourth embodiment, and, for example, a vacuum vapor deposition method is preferably used. Next, a conventional organic EL element is formed on the optical path length correction layer referring to the fourth embodiment.

If the organic EL device with optical path length correction layer is manufactured according to this method, the manufacturing conditions of the conventional organic EL device can be basically directly used.

However, it is also possible to basically form the first optical path length correction layer first, form the anode layer thereon, and then form the second optical path length correction layer. When formed in this way, it is suitable for organic EL devices corresponding to the three primary colors (red, blue, and green) with different types or thicknesses of the optical path length correction layer.

[Example]<u style="single">Example 1</u>(1) Preparations for manufacturing organic EL elements

The organic EL device of Example 1 has the structure shown in Figure 1. When the manufacturing starts, firstly, a transparent glass substrate 22 with a thickness of 1.1 mm, a length of 200 mm, and a width of 200 mm is formed of ITO with a thickness of 130 mm. The formed transparent electrode film serves as the anode layer. Hereinafter, this glass substrate 22 and the anode layer 10 are combined into a substrate 30.

Next, the substrate 30 is ultrasonically cleaned with isopropanol, and the substrate 30 is cleaned in N₂After drying in a (nitrogen) atmosphere, wash with UV (ultraviolet rays) and ozone for 10 minutes.

Next, as shown in FIG. 34, the substrate 30 is mounted on the substrate holder 211 of the vacuum chamber 210 in the vacuum evaporation device 201, and the 4,4'-bis(2,2-diphenyl) Vinyl) biphenyl (hereinafter referred to as DPVBi) is filled in the evaporation source 212A, and 4,4'-bis[2-(4-(N,N-di-p-tolyl)phenyl)vinyl] is combined Benzene (hereinafter referred to as DTAVBi) is filled in the vapor deposition source 212B, and phen(8-phenol)aluminum (hereinafter referred to as Alq) constituting the electron injection layer 14 is filled in the vapor deposition source 212C to form a part of the electron injection layer 14. A part of the reducing dopant (Li) is filled in the evaporation source 212D, and the metal aluminum (A1) constituting the cathode layer 16 is filled in the evaporation source 212E.

(2) Manufacturing of organic EL elements

It blows to reduce the pressure in the vacuum tank 210 shown in Figure 34 to 6×10^-⁵After the vacuum degree is below Pa, the transparent electrode (ITO film) 10 of the substrate 30 is simultaneously vapor-deposited on the blue organic light-emitting layer 12 made of DPVBi and DTAVBi, the electron injection layer 14 made of Alg and Li, and made of aluminum The cathode layer 16 is laminated in this order to produce the organic EL device 100.

At this time, the total optical path length (t1) of the transparent electrode and the blue organic light-emitting layer (including the electron injection layer) is configured such that the optical path length (Min) that can exhibit the minimum value of the CIEy chromaticity coordinate is 430 nm.<img file="TW463528B_D0002.tif" />

(3) Evaluation of organic EL components

The cathode layer 16 in the obtained organic EL device 100 was used as a negative (-) electrode, and the transparent electrode 10 was used as a positive (+) electrode, and a DC voltage of 7V was applied between the two electrodes. At this time, the current density is 1.3Ma/cm²And the value of the luminous intensity measured by the luminance meter (hereinafter, the same measurement is carried out on the luminous intensity) is 39 cd/m². In addition, the CIE chromaticity coordinates measured in accordance with JIS Z8701 are CIEx=0.150 and CIEy=0.223 for the luminous chromaticity, and it has been confirmed that blue luminescence with an excellent hue can be obtained.

Furthermore, after measuring the half-life of this organic EL device, it was confirmed that it has a long life of 1,000 hours or more. Here, the half-life refers to the time required for the luminous brightness to become the half value of the maximum brightness. For example, in Example 1, the luminous brightness is from the maximum brightness of 100cd/m²Reach its half value of 50cd/m²The meaning of time needed.

<u style="single">Example 2</u>

In Example 2, the use of Alg and coumarin 6 co-evaporation as the green color had the method of making the optical path length (Max) exhibiting the maximum value of CIEy approximately 500 nm, and the organic EL device was prepared in accordance with Example 1. Therefore, applying a DC voltage of 7V and evaluating the performance of the device, the current density is 1.1mA/cm²And the luminous brightness is 70cd/m². In addition, the CIE chromaticity coordinate values in accordance with JIS Z8701 are CIEx=0.256 and CIEy=0.655, and it has been confirmed that green light emission with excellent hue can be obtained.

<u style="single">Example 3</u>

In Example 3, 4-dicyano-methylene-2-methyl-6-(p-dimethylaminostyryl)-4H-an was co-evaporated together with A1q to form a red organic layer that emits light Layer (film thickness 57nm), and the total optical path length (t2) can be consistent with the optical path length (Max) showing the maximum value of CIEx, 390nm, and the other organic EL devices were fabricated according to Example 1.

Next, as a result of applying a DC voltage of 7V between the electrodes in the obtained organic EL device and performing device performance evaluation, the current density was 0.98mA/cm²And the luminous brightness is 25cd/m²。

In addition, the values of CIE chromaticity coordinates in accordance with JIS Z 8701 are CIEx=0.655 and CIEy=0.352, and it has been confirmed that red light emission with excellent hue can be obtained.

<u style="single">Example 4</u>

In Example 4, as the optical path length correction layer, magnesium oxide (film thickness: 20 nm) was inserted between the glass substrate and the transparent electrode, and the organic light-emitting layer was made to be 58 nm. Other than that, an organic EL element was produced in accordance with Example 1. At this time, the value of the total optical path length is set to 430 nm so as to coincide with 430 nm of the optical path length (Min) which exhibits the minimum value of CIEy.

Next, a DC voltage of 7V was applied between the electrodes in the obtained organic EL device and the performance of the device was evaluated. The current density was 1.1mA/cm.²And the luminous brightness is 33cd/m²。

In addition, the values of CIE chromaticity coordinates in accordance with JIS Z8701 are CIEx=0.151 and CIEy=0.224. That is, by inserting the optical path length correction layer, the CIEy value of Comparative Example 1 in which the optical path length correction layer is not inserted can be lowered by 0.01 and it has been confirmed that blue light emission with a better hue can be obtained.

<u style="single">Example 5</u>

In Example 5, as the optical path length correction layer, a layer made of magnesium oxide (film thickness: 20nm) was inserted between the electron injection layer and the cathode layer, and the organic light-emitting layer was made to be 58nm. Other than that, the organic light-emitting layer was made according to Example 1. EL element. At this time, the value of the total optical path length is set to 430 nm so as to coincide with 430 nm of the optical path length (Min) which is the minimum value of CIEy.

After blowing, a DC voltage of 7V was applied between the electrodes in the obtained organic EL device and the performance of the device was evaluated. The current density was 0.90mA/cm.²And the luminous brightness is 26cd/m²。

In addition, the values of the CIE chromaticity coordinates in accordance with JIS Z 8701 are CIEx=0.151 and CIEy=0.224. That is, by inserting the optical path length correction layer, the CIEy value of Comparative Example 1 in which the optical path length is not inserted can be reduced by 0.01 and it is confirmed that blue light emission with a better hue can be obtained.

<u style="single">Example 6</u>

In Example 6, as the optical path length correction layer, a ketone cyanine layer (film thickness of 19 nm) was inserted between the transparent electrode and the organic light-emitting layer, and the organic light-emitting layer was made to other than 58 nm. The other organic EL elements were fabricated according to Example 1. . At this time, the value of the total optical path length is set to 430 nm so as to coincide with 430 nm of the optical path length (Min) which is the minimum value of CIEy.

Next, a DC voltage of 7V was applied between the electrodes in the obtained organic EL device and the device performance was evaluated. The current density was 1.2mA/cm.²And the luminous brightness is 38cd/m²。

In addition, the values of CIE chromaticity coordinates in accordance with JIS Z 8701 are CIEx=0.151 and CIEy=0.225. That is, by inserting the optical path length correction layer, the CIEy value of Comparative Example 1 in which the optical path length correction layer is not inserted can be reduced by 0.01, and it is confirmed that blue light emission with a better hue can be obtained.

<u style="single">Comparative example 1</u>

In Comparative Example 1, an organic EL device was produced in accordance with Example 1, except that the thickness of the organic light-emitting layer was 58 nm. At this time, the value of the total optical path length is 392nm, and the relationship between the minimum optical path length Min showing the CIEx chromaticity coordinate or the CIEy chromaticity coordinate and the maximum optical path length Max is not satisfied. Those related to the size of the following. Min-20nm&lt;total optical path length&lt;Min+20nmMax-20nm&lt;total optical path length&lt;Max+20nm Then, a DC voltage of 7V is applied between the electrodes in the obtained organic EL device and the performance of the device is evaluated. The current density is 1.5mA /cm²And the luminous brightness is 35cd/m²。

In addition, the values of the CIE chromaticity coordinates measured in accordance with JIS Z 8701 are CIEx=0.158 and CIEy=0.235. In Comparative Example 1, it was confirmed that the value of CIEy was greatly shifted to the green side of blue-green light emission.

In addition, in Fig. 26, when compared with Example 1, the relationship between the total optical path length and CIEy in Comparative Example 1 is shown.

<u style="single">Comparative example 2</u>

In Comparative Example 2, an organic EL device was produced in accordance with Example 1, except that the thickness of the blue organic light-emitting layer was set to 102 nm. At this time, the value of the total optical path length is 468 nm where the dry structure peak and the luminescence peak coincide with each other. Among the relationships between, none of them can satisfy the following relationship. Min-20nm&lt;total optical path length&lt;Min+20nmMax-20nm&lt;total optical path length&lt;Max+20nm

Then, a DC voltage of 7V was applied between the electrodes in the obtained organic EL device and the device performance was evaluated. The current density was 1.1mA/cm.²And the luminous brightness is 35cd/m²。

In addition, the values of the CIE chromaticity coordinates measured in accordance with JIS Z 8701 are CIEx=0.148 and CIEy=0.232, and when compared with Example 1, it is confirmed that the value of CIEy is a bluish-green light that shifts greatly to the green side. In addition, in Fig. 26, when compared with Example 1, the relationship between the total optical path length and CIEy in Comparative Example 2 is shown respectively.

<u style="single">Comparative example 3</u>

In Comparative Example 3, except that the thickness of the green organic light-emitting layer was set to 81 nm, the other organic EL devices were produced in accordance with Example 2. At this time, the value of the total optical path length is 430nm, and the relationship between the minimum value of the CIEx chromaticity coordinate or the CIEy chromaticity coordinate of the optical path length Min and the maximum value Max fails to satisfy the following magnitudes Relationship person. Min-20nm&lt;total optical path length&lt;Min+20nmMax-20nm&lt;total optical path length&lt;Max+20nm

Then, a DC voltage of 7V was applied between the electrodes in the obtained organic EL device and the device performance was evaluated. The current density was 1.5mA/cm.²Luminous brightness is 27cd/m²。

In addition, the CIE chromaticity coordinate values measured in accordance with JIS Z 8701 are CIEx=0.288 and CIEy=0.640. When compared with Example 2, it was confirmed that the value of CIEy is quite small and will become yellow-green light emitting that shifts to yellow. In addition, in Figure 24, when compared with Example 2, the relationship between the total optical path length and CIEy in Comparative Example 3 is shown.

<u style="single">Comparative example 4</u>

In Comparative Example 4, an organic EL device was produced in accordance with Example 3 except that the thickness of the red organic light-emitting layer was 92 nm. At this time, the value of the total optical path length is 450 nm, and the relationship between the optical path length Min, which represents the minimum value of CIEx chromaticity coordinates or CIEy chromaticity coordinates, and the optical path length Max, which represents the maximum value, fails. Meet the following size relationship. Min-20nm&lt;total optical path length&lt;Min+20nmMax-20nm&lt;total optical path length&lt;Max+20nm

Then, a DC voltage of 7V was applied between the electrodes in the obtained organic EL device and the device performance was evaluated. The current density was 1.5mA/cm.²,Luminous brightness is 27cd/m²。

In addition, the values of the CIE chromaticity coordinates measured in accordance with JIS Z 8701 are CIEx=0.625 and CIEy=0.375. When compared with Example 3, it was confirmed that the value of CIEx is quite small and it will emit yellowish red-yellow light.

In addition, in Fig. 25, when compared with Example 4, the relationship between the total optical path length and CIEx in Comparative Example 4 is shown respectively.<tables><img file="TW463528B_D0003.tif" /></tables>

<u style="single">Example 7</u>(1) Fabrication of organic EL element Formation of anode (lower electrode)

A glass substrate (OA2 glass, manufactured by Nippon Electric Glass Co., Ltd.) with a length of 112 mm, a width of 143 mm, and a thickness of 1.1 mm is spin-coated with V259 BK (manufactured by Nippon Steel Chemical Co., Ltd.) as the constituent material of the black matrix (BlackMatrix, BM) ). Next, ultraviolet light exposure is performed through a grid pattern mask, and the unexposed area is developed using a 2% by weight sodium carbonate aqueous solution. It was then baked at 200°C to form a black matrix (film thickness 1.5 μm).

Next, the acrylic thermosetting resin V259 PH (manufactured by Nippon Steel Chemical Co., Ltd.), which is the constituent material of the planarization film, was spin-coated on the black matrix and baked at 160°C to form a planarization film (film thickness 5 μm).

Next, an indium zinc oxide layer (IZO) with a thickness of 200 nm is formed on the planarization film by a sputtering method.

Next, a positive photoresist HPR 204 (manufactured by Fuji Hunter Electronic Technology Co., Ltd.) was spin-coated on the indium zinc oxide layer, and dried at 80° C. for 10 minutes.

Next, as shown in Fig. 22, while making the cathode take-out part 20 a mask, contact exposure is performed with a high-pressure mercury lamp as a light source through a mask with a stripe pattern (line width 90 μm, gap width 20 μm) After that, the exposed part was developed using TMAH (tetramethylammonium hydroxide). Thereafter, it was baked at 130°C for 10 minutes to form a photoresist film.

Next, after etching the indium zinc oxide layer exposed in the photoresist film with a 5 wt% oxalic acid aqueous solution as an etchant, a stripping solution N303 (manufactured by Nagase Sangyo Co., Ltd.) was used to remove the positive photoresist HPR 204, and As shown in FIG. 22, a striped IZO pattern (960 lines) 14 used as an anode (lower electrode) is formed on the glass substrate 12.

The formation of the first interlayer insulating film

Then, spin-coated acrylic negative photoresist V259PA (manufactured by Nippon Steel Chemical Co., Ltd.) on the IZO pattern, and a striped pattern mask (line width 90 μm, gap width) intersecting the IZO pattern perpendicularly 20 μm), after drying at a temperature of 80°C and a time of 10 minutes, the exposure will be 100 mJ/cm²The method uses a high-pressure mercury lamp as the light source for contact exposure.

Press, use TMAH as the developing solution to develop the unexposed area, and then use the oven to perform post-baking treatment at 160°C for 10 minutes, as shown in Figure 22, to form the first interlayer insulating film (IZO The opening 70μm×290μm)16.

The formation of the second interlayer insulating film

Next, a negative photoresist ZPN1100 (manufactured by Nihon Koen Co., Ltd.) was spin-coated from the top of the first interlayer insulating film to have a linear pattern (line width 20 μm, gap width 310 μm) through the IZO pattern parallel to the lower electrode. After drying at 80°C for 10 minutes, the exposure can be 100mJ/cm²The method uses a high-pressure mercury lamp as the light source for contact exposure.

Next, use TMAH as a developing solution to develop the unexposed areas, and then use an oven to perform post-baking treatment at 160°C for 10 minutes, as shown in Figure 22, to form a second interlayer insulating film for partition walls (Line width 20μm, gap width 310μm) 18.

Washing process

Next, the glass substrate on which the IZO pattern and the like are formed (hereinafter may only be referred to as the glass substrate) is subjected to ultrasonic cleaning with isopropanol, and drying air is sprayed to dry it. Then, it is applied by a UV ozone cleaning device (manufactured by Sanmotech Co., Ltd.). Give 30 minutes of UV washing.

The formation of organic light-emitting media

Next, the glass substrate on which the IZO pattern and the like are formed is fixed to the substrate holder 211 in the vacuum vapor deposition apparatus (manufactured by Nippon Vacuum Technology Co., Ltd.) 210 as shown in FIG. 34.

Then, the following materials are respectively filled in the molybdenum heating plates 212A to E in the vacuum evaporation apparatus 201 shown in FIG. 34.

Positive hole injection material: 4.4'.4"-parameter [N-(3-methylphenyl)-N-phenylamino] triphenylamine (MTDATA), positive hole transport material: 4,4'-double [N-(1-yl)-N-phenylamino]-biphenyl (NPD),

Organic light-emitting materials: 4,4'-bis(2,2-diphenylvinyl)biphenyl (DPVBi) and 4,4'-bis[2-(4-(N,N-di-p-tolyl) )Phenyl)vinyl)biphenyl (DTAVBi)

Electron injection material: Ref. (8-Phenol) aluminum (Alq) In addition, as the counter electrode (cathode) material, an Al-Li alloy (Li concentration 10 atomic%) is attached to a tungsten filament BF-1 (Japan) Made by Baker Smeida) (as shown by the symbol 212F on Figure 34).

Next, reduce the vacuum degree of the vacuum evaporation device to 6×10^-⁵Pa, according to the following method of vapor deposition speed and film thickness, from the positive hole injection layer to the formation of the cathode, the vacuum state is still maintained during the process, and the vacuum is blown in sequence to form the organic light emitting layer. Media etc. In addition, the DPVBi and DPVBi systems were simultaneously vapor-deposited under the following conditions to form a total film thickness of 40 nm.

In addition, each film thickness means the value of the central part of the organic light-emitting medium, so the total optical path length at the central part is 680 nm, and the total optical path length of the transparent electrode and the organic light-emitting medium (blue light-emitting organic layer) is As shown in Figure 27, it is approximately 670nm, which is the maximum value of the CIEy chromaticity coordinate.

In addition, the film thickness distribution in the plane of each organic light-emitting medium is measured with an ellipsometer, and the result is a value of ±1% of the average value. Therefore, since there is substantially no film thickness distribution of the transparent electrode, it can be said that the distribution of the total optical path length is also a value of ±1% of the average value. MTDATA: vapor deposition rate 0.1 to 0.3nm/sec., film thickness 76nm NPD: vapor deposition rate 0.1 to 0.3nm/sec., film thickness 20nm DPVBi: vapor deposition rate 0.4nm/sec., total film thickness 40nmDTAVBi: vapor deposition rate 0.1 nm/sec. Alq: vapor deposition rate 0.1 to 0.3nm/sec., film thickness 20nm Al-Li: vapor deposition rate 0.5 to 1.0nm/sec., film thickness 150nm

Packaging process

Next, a glass substrate (blue glass) for packaging is laminated on the cathode side in the packaging device, and the surrounding area is sealed with a cation-curing bonding agent TB3102 (three-stranded (strand)) to form a lower electrode and an upper electrode. The formed XY matrix (Matrix) is an organic EL element (320×240 pixels, 56% aperture ratio).

(2) Evaluation of organic EL components

As a result of applying a DC voltage of 7V between the transparent electrode (anode) and the counter electrode (cathode) in the obtained organic EL element, the intersection of each electrode (pixel) emits light. Next, the luminescence brightness and chromaticity distribution were measured using a luminescence distribution measuring device CA-1000 (manufactured by Minolta Co., Ltd.).

As a result, the difference between the maximum value and the minimum value of CIEx was 0.0046, and the difference between the maximum value and the minimum value of CIEy was 0.0010, and it was confirmed that it was an organic EL device with extremely excellent blue hue and little blue hue change.

In addition, the in-plane distribution of the luminous intensity measured by a luminance meter was confirmed to be a small value within 5% of the average.

<u style="single">Comparative example 5</u>

In Comparative Example 5, except that the film thickness of MTDATA was set to 120 nm and the total optical path length was set to 760 nm, an organic EL element (320×240 pixels, 56% aperture ratio) was prepared and evaluated in accordance with Example 7.

As a result, the total optical path length at the center is about 760nm, the difference between the maximum and minimum values of CIEx is 0.0039, and the difference between the maximum and minimum values of CIEy is 0.023, and it is confirmed that the in-plane distribution of luminous intensity is even The value is a small value within 5%.

Therefore, compared with Example 7, the difference between the maximum value and the minimum value of CIEy is increased to more than 20 times, and the color purity of the blue-green color recognized as blue-green from the light-emitting place of the pixel is low.

<u style="single">Example 8</u>(Production of organic EL elements)

In Example 8, apart from the formation process of the black matrix (BM) and the formation process of the planarization layer, the following blue color filter formation process, green conversion film formation process, and red conversion film formation process were set respectively as follows Except for the process, the other organic EL elements were produced in the same manner as in Example 7 (the number of pixels was 320×240, and the aperture ratio was 56%).

That is, as the material of the blue color filter, V259B (manufactured by Nippon Steel Chemical Co., Ltd.) is spin-coated, and the interlayer has a striped pattern (line width 90nm, gap width 240μm, and 320 stripes). At the same time as the mask, make the exposure amount 100mJ/cm while aligning the mask with the black matrix.²A high-pressure mercury lamp is used as the light source for contact exposure. Thereafter, a 2% by weight sodium carbonate aqueous solution was used for development, and then baked at 200° C. for 10 minutes to form a blue color filter plate (thickness 1.5 μm).

Then, on the blue color filter plate, a combination of 0.04 mol/kg (to solid content) of coumarin 6 and acrylic negative photoresist V259 PA (manufactured by Nippon Steel Chemical Co., Ltd., solid content 50 (Wt%) spin coating of the mixed material, as the material of the green conversion film. Then, move the mask used to form the blue color filter to the stripe pattern of the blue color filter only by 110μm pitch in the vertical direction of the plane to align the position, and make the exposure 100mJ/cm²A high-pressure mercury lamp is used as the light source for contact exposure. Thereafter, a 2% by weight sodium carbonate aqueous solution was used for development, and then baked at 200°C for 10 minutes to form a green conversion film (thickness 10 μm).

Then, on the green conversion film, as the material of the red conversion film, 0.53g of Coumarin 6, 1.5g of Basic Violet 11, 1.5g of Basic Rouge Red 6G, and 100g of Acrylic Negative Light The mixed material made of resisting V259 PA (manufactured by Nippon Steel Chemical Co., Ltd., with a solid content of 50% by weight) is spin-coated. Then, the mask used to form the blue color filter is moved to the vertical direction of the plane by only 220μm pitch of the stripe pattern of the blue color filter to align the position, and the exposure amount becomes 100mJ/cm²A high-pressure mercury lamp is used as the light source for contact exposure. After that, a 2% by weight sodium carbonate aqueous solution was used for development, and then baked at 160°C for 10 minutes to form a red conversion film (thickness 10 μm).

In this way, the blue conversion film 27, the green conversion film 26, the red conversion film 25, and the color filter plate 10 containing a black matrix as shown in FIG. 23 are produced.

Here, the total optical path length of the transparent electrode, the blue color filter, the planarization layer, and the organic light-emitting medium (blue light-emitting organic layer) is 680nm, and as shown in Figure 27, it is close to the minimum of the CIEy chromaticity coordinates. The value is 670nm.

(Evaluation of organic EL elements)

As a result of applying a DC voltage of 7V between the transparent electrode (anode) and the counter electrode (cathode) in the obtained organic EL element, the intersection of each electrode (pixel) emits light. Next, the luminescence brightness and chromaticity distribution were measured using a luminescence distribution measuring device CA-1000 (manufactured by Minolta Co., Ltd.).

As a result, the pixel at the position corresponding to the blue color filter plate will obtain blue light with excellent color purity, and the difference between the maximum and minimum values of CIEx is 0.0017, and the difference between the maximum and minimum values of CIEy is 0.0029 . In addition, the result of measuring the distribution of luminous intensity using a luminance meter, it is confirmed that the in-plane distribution is a small value within 8% of the average value.

In addition, for comparison with Comparative Example 6 and the like, the values of CIEx and CIEy for blue light emission, the light emission luminance distribution and the light emission color, and the obtained results are shown in Table 2.

In addition, the pixel at the position corresponding to the green conversion film will obtain green light, and the difference between the maximum and minimum values of CIEx is 0.0057, and the difference between the maximum and minimum values of CIEy is 0.0008. In addition, the result of measuring the distribution of luminous intensity using a luminance meter, it is confirmed that the in-plane distribution is a small value within 5% of the average value.

In addition, the pixel at the position corresponding to the red conversion film will obtain red luminescence, and the difference between the maximum value and the minimum value of CIEx is 0.0017, and the difference between the maximum value and the minimum value of CIEy is 0.00022. In addition, the result of measuring the distribution of luminous intensity using a luminance meter, it is confirmed that the in-plane distribution is a small value within 5% of the average value.

Furthermore, white light emission can be obtained by fully igniting the lights and using the light interference effect. In this case, the difference between the maximum and minimum values of CIEx is 0.0036, and the difference between the maximum and minimum values of CIEy is 0.00084. In addition, it has been confirmed that the in-plane distribution of luminous brightness is a small value within 5% of the average value.

Furthermore, when all lights are lit in this way to emit white light, the average luminous brightness of the organic EL element is 96.8 cd/m², CIEx has a chromaticity of 0.2934 and CIEy has a chromaticity of 0.3471. Therefore, if such an organic EL element is used, blue, green, red, and white light emission with extremely small CIEy chromaticity difference and excellent color purity can be obtained, and it is confirmed that a full-color display that can emit a desired color can be obtained.

<u style="single">Comparative example 6</u>

In Comparative Example 6, except that the film thickness of MTDATA of Example 8 was set to 120 nm, an organic EL element (320×240 pixels, 56% aperture ratio) was fabricated and evaluated in accordance with Example 8.

Here, the total optical path length of the transparent electrode, the blue color filter, the planarization layer, and the organic light-emitting medium (blue light-emitting organic layer) is about 760nm, and the minimum value (Min) and maximum value in the CIEx chromaticity coordinate The value (Max), or the relationship between the minimum value (Min) and the maximum value (Max) of the CIEy chromaticity coordinates, respectively fails to satisfy the following magnitude relationships. Min-20nm&lt;total optical path length&lt;Min+20nmMax-20nm&lt;total optical path length&lt;Max+20nm

As a result, the pixel at the position corresponding to the blue color filter plate will obtain blue light emission. The difference between the maximum and minimum values of CIEx is 0.00028, and the difference between the maximum and minimum values of CIEy is 0.013. In addition, the in-plane distribution of luminous brightness is a value within 5% of the average value.

In addition, for comparison with Example 8 and the like, the results obtained are shown in Table 2 regarding the CIEx and CIEy values of blue light emission, and regarding the emission luminance distribution and emission color.

In addition, the pixel at the position corresponding to the green conversion film will obtain green light emission, and the difference between the maximum value and minimum value of CIEx is 0.0019, the difference between the maximum value and the minimum value of CIEy is 0.0090, and the luminous intensity is distributed in the plane The value is within 5% of the average value.

In addition, the pixel at the position corresponding to the red conversion film will obtain red luminescence, and the difference between the maximum value and the minimum value of CIEx is 0.0025, and the difference between the maximum value and the minimum value of CIEy is 0.0032. The internal distribution is a value within about 5% of the average value.

Furthermore, by fully lighting up and using the light interference effect, white light emission can be obtained. The difference between the maximum and minimum values of CIEx is 0.0021, and the difference between the maximum and minimum values of CIEy is 0.018. The in-plane distribution of luminous brightness is Values within 5% of the average value. Moreover, when the white light is emitted in this way, the average luminance of the organic EL element is 120.3 cd/m², And the CIEx chromaticity is 0.2909 and the CIEy chromaticity is 0.4223.

Therefore, when making white light emission in this way, when compared with Example 8, it was confirmed that the chromaticity difference of CIEy was large and it would become greenish white light emission.

In addition, in terms of the average luminance of the organic EL element, when compared with Example 8, the value of Comparative Example 6 becomes a higher value, which is caused by the visual influence caused by the shift of the white light emission to the green side. For example, those with better whiteness are ideal because they can obtain the desired hair color in the case of image display. Therefore, although the average brightness of Comparative Example 6 is relatively high, it can be said that it is inferior to that of Example 8 in terms of color purity.

<u style="single">Example 9</u>

In Example 9, the glass substrate (OA2 glass, manufactured by Nippon Electric Glass Co., Ltd.) of 112 mm in length, 143 mm in width, and 1.1 mm in thickness in Example 8 was replaced with a glass substrate of 260 mm in length, 210 mm in width, and 1.1 mm in thickness. Otherwise, an organic EL element (640×480 pixels, 56% aperture ratio) was produced in the same manner as in Example 8 and evaluated.

Here, the total optical path length of the transparent electrode, the blue color filter, the planarization layer, and the organic light-emitting medium (blue light-emitting organic layer) is about 680 nm, as shown in Figure 27, which is approximately the CIEy chromaticity coordinate. The value is 670nm.

As a result, the pixel at the position corresponding to the blue color filter plate will obtain blue light, and the difference between the maximum and minimum values of CIEx is 0.0049, the difference between the maximum and minimum values of CIEy is 0.010, and the luminance The in-plane distribution is within 23% of the average value.

In addition, for comparison with Comparative Example 7 and the like, the values of CIEx and CIEy for blue light emission, and the emission luminance distribution and emission color are shown in Table 2.

In addition, the pixel at the position corresponding to the green conversion film will obtain green light emission, and the difference between the maximum and minimum values of CIEx is 0.0017, the difference between the maximum and minimum values of CIEy is 0.0037, and the luminous intensity is distributed in the plane. The value is within 12% of the average value.

In addition, the pixel at the position corresponding to the red conversion film will obtain red luminescence, and the difference between the maximum value and the minimum value of CIEx is 0.0053, and the difference between the maximum value and the minimum value of CIEy is 0.0018, and the luminous intensity is distributed in the plane. The value is within about 15% of the average value.

Furthermore, by fully lighting up and using the light interference effect, white light emission can be obtained. The difference between the maximum and minimum values of CIEx is 0.010, and the difference between the maximum and minimum values of CIEy is 0.0068. The in-plane distribution of luminous brightness is Values within 14% of the average value. In addition, when it emits white light in this way, the average luminance of the organic EL element is 96.8cd/m², And the chromaticity of CIEx is 0.2934 and the chromaticity of CIEy is 0.3471.

Therefore, if this type of organic EL element is used, although the panel area has increased and the distribution of the luminous intensity of each color has increased, it has been confirmed that CIEy has a particularly small chromaticity difference and excellent color purity. Blue, green, red and white glowing gold colors (fullcolor).

<u style="single">Comparative example 7</u>

In Comparative Example 7, an organic EL element (640×480 pixels, 56% aperture ratio) was produced and evaluated in the same manner as in Example 9 except that the film thickness of MTDATA in Example 9 was 120 nm. Here, the total optical path length of the transparent electrode, the blue color filter, the planarization layer and the organic light-emitting medium (blue light-emitting organic layer) is 760nm, and the minimum value (Min) and maximum value (Max) of CIEx chromaticity coordinates , Or the relationship between the minimum value (Min) and the maximum value (Max) of the CIEy chromaticity coordinates, respectively, fails to satisfy the following magnitude relationship values. Min-20nm&lt;total optical path length&lt;Min+20nmMax-20nm&lt;total optical path length&lt;Max+20nm

As a result, the pixel at the position corresponding to the blue color filter plate will obtain blue light emission, and the difference between the maximum and minimum values of CIEx is 0.0020, the difference between the maximum and minimum values of CIEy is 0.036, and the luminance The in-plane distribution is within 7% of the average value.

In addition, for comparison with Example 9 and the like, the values of CIEx and CIEy for blue light emission, the light emission luminance distribution and the light emission color, and the obtained results are shown in Table 2.

In addition, the pixel at the position corresponding to the green conversion film will obtain green light emission. The difference between the maximum and minimum values of CIEx is 0.0067, and the difference between the maximum and minimum values of CIEy is 0.025. The in-plane distribution of luminescence brightness is Values within 8% of the average value.

In addition, the pixel at the position corresponding to the red conversion film will obtain red light, and the difference between the maximum and minimum values of CIEx is 0.0071, and the difference between the maximum and minimum values of CIEy is 0.0091, and the luminous intensity is distributed in the plane. It is a value within about 8% of the average value.

Furthermore, by fully lighting up and using the light interference effect, white light emission can be obtained. The difference between the maximum and minimum values of CIEx is 0.0031, and the difference between the maximum and minimum values of CIEy is 0.037. The in-plane distribution of luminous brightness is Values within 5% of the average value. Also, in this way to make it glow white,

The average brightness of the organic EL element is 120.3cd/m², And the chromaticity of CIEx is 0.2909 and the chromaticity of CIEy is 0.4223. Therefore, in the case of making white light emission in this way, when compared with Example 9, it was confirmed that the chromaticity difference of CIEy was particularly large and it would become greenish white light emission.

In addition, when comparing the average luminescence brightness of the organic EL element with Example 9, although Comparative Example 7 has a higher value, as explained in Example 8, this is due to the shift of the white light emission to the green side. Caused by the visual influence of the person.<tables><img file="TW463528B_D0004.tif" /></tables>The measurement result is only the luminescence data obtained through the blue color filter.

[Industrial use field]

As explained above, if the organic EL device of the present invention is used, the total optical path length of the transparent electrode and the organic layer is determined by considering the maximum value and minimum value of the CIE chromaticity coordinate value measured in accordance with JIS Z 8701 to make the organic layer In the case of a large area, even if the total optical path length of the transparent electrode and the organic layer deviates to a certain extent, the CIE chromaticity coordinate can be reduced and the light emission with excellent color tone can be obtained.

Therefore, the technology of the present invention, even if the area of the organic layer in the organic EL element is enlarged, for example, if it is made into a mold of 10 inches or more, and the thickness of the organic layer varies, it can achieve excellent color tone. In terms of light emission, it can be described as an extremely effective technology.

In addition, if the organic EL device manufacturing method of the present invention is used, even if the organic layer is made into a large area and the total optical path length of the transparent electrode and the organic layer is deviated to a certain extent, the CIE chromaticity coordinates can still be changed It is small and can effectively produce organic EL elements with excellent color tone.