Multi-color light-emitting display device

The present invention relates to a multicolor light emitting display device that displays an image using four colors of light.

Conventionally, it is widely known that light of three primary colors is used in a display device in order to realize a full-color image. For example, in a display to which an organic electroluminescence element (hereinafter referred to as an organic EL element) is applied as a self-luminous light source, innumerable pixels are provided on the display area, and each pixel emits R, G, and B light. Consists of emitting sub-pixels. The output value of each sub-pixel (RGB) is adjustable, and by adjusting the output value of each sub-pixel, each pixel can emit light of a desired color.

Here, in order to emit RGB light from each sub-pixel, for example, as described in Patent Document 1, a method of extracting RGB light from white light using an RGB color filter is known. Further, for example, a method is also known in which an organic EL element is manufactured by a three-color painting method, and an organic EL element that emits red, green, and blue is provided for each subpixel.

By the way, in order to properly display a full-color image on a display, a transmission method is standardized as an NTSC method in a color television. In the NTSC system, the chromaticity coordinates of each of RGB are standardized as follows in order to improve the color reproducibility of the transmitted image. R = (0.64,0.33) G = (0.21,0.71) B = (0.15,0.06)

Further, on a monitor of a personal computer or the like, the chromaticity coordinates of the three primary colors of colors are standardized as sRGB as follows so that images and the like exchanged on a network or the like can be appropriately displayed. R = (0.64,0.33) G = (0.30,0.60) B = (0.15,0.06)

If the light of the above standardized RGB color can be emitted, the color in the region surrounded by the xy coordinates of each of the above RGB can be expressed by combining these RGB on the display.<patcit num="1"><text>Japanese Patent No. 3451680</text></patcit>

<p> On the other hand, the visible light region in which a person can biologically perceive light is wider than the region surrounded by the NTSC system or the RGB coordinates of sRGB, and light of a color outside the region can also be perceived. However, such colors cannot be properly expressed on the display in the NTSC system and the sRGB system. For example, colors that are perceived as different colors by the human eye are the same on the display. May be displayed as a color. That is, it cannot be said that the current display can sufficiently express the colors that human beings can perceive biologically.</p><p> Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a display device capable of more appropriately expressing a full-color image.</p>

<p> The multicolor light emitting display device according to the present invention is a red subpixel that emits red light, a blue subpixel that emits blue light, a green subpixel that emits green light, and a blue-green that emits blue-green light that is an intermediate color between blue and green. It is composed of a plurality of pixels including subpixels, and the emission colors of the blue-green subpixels have x and y values lower than the x and y values of the green subpixel, respectively, in xy chromaticity coordinates, and red, green, The blue and turquoise subpixels are xy chromaticity coordinates (0.65 ± 0.05, 0.35 ± 0.05), (0.20 ± 0.10, 0.70 ± 0.10), (0.15 ± 0.05, 0.06 ± 0.05), and (0.05 ± 0.05, respectively). It is characterized by emitting colored light of 0.60 ± 0.10). The xy chromaticity coordinates are the chromaticity coordinates in the CIE (International Commission on Illumination) 1931 chromaticity diagram.</p><p> The red, green, blue, and turquoise subpixels include, for example, red, green, blue, and turquoise organic EL elements that emit red, green, blue, and turquoise light, respectively.</p><p> Of the red, green, blue, and turquoise subpixels, subpixels of at least one color contain a filter corresponding to that color, and the subpixels containing the filter allow light from the organic EL element to pass through the filter. It is preferable to obtain colored light. In the present invention, by combining an organic EL element and a filter, each subpixel can emit light having desired chromaticity coordinates.</p><p> The blue, green, red, and turquoise subpixels more preferably contain blue, green, red, and turquoise filters, respectively, to allow light from the blue, green, red, and turquoise organic EL elements to be blue, green, respectively. , Red, and turquoise filters are used to obtain colored light. Further, in the blue-green filter, it is preferable that the wavelength having the maximum transmittance is larger than the wavelength having the maximum transmittance of the blue filter and smaller than the wavelength having the maximum transmittance of the green filter.</p><p> When the red subpixel contains a red filter, for example, the wavelength at which the emission brightness of the light emitted from the red organic EL element is maximized is located in any of the ranges of 600 to 650 nm, and the transmittance of the red filter is maximum. The wavelength is located above 600 nm. When the green subpixel contains a green filter, for example, the wavelength at which the emission brightness of the light emitted from the green organic EL element is maximized is located in any of the ranges of 510 to 550 nm, and the transmittance of the green filter is maximum. The wavelength is located in any of the range of 510 to 550 nm. When the blue subpixel includes a blue filter, for example, the wavelength at which the emission brightness of the light emitted from the blue organic EL element is maximized is located in any of the ranges of 430 to 470 nm, and the transmittance of the blue filter is maximum. The wavelength is located in any of the range of 430 to 470 nm. By appropriately combining the organic EL element and the filter in this way, the red, green, and blue sub-pixels can emit light having high color purity and desired chromaticity coordinates, respectively.</p><p> For the blue-green organic EL element, for example, BAlq is used as the light emitting material of the light emitting layer. In this case, for example, the turquoise subpixel includes a turquoise filter, and the turquoise filter has a transmittance of 20% or less in the wavelength range of 430 to 470 nm, and the wavelength at which the transmittance is maximized is set to 490 to 510 nm. And its maximum transmittance is set to 60% or more. By setting the filter in this way, when BAlq is used as the light emitting material of the light emitting layer of the blue-green organic EL element, the blue-green subpixel can emit blue-green light having high color purity.</p><p> The backlight for a liquid crystal display according to the present invention is a backlight for a liquid crystal display that irradiates a liquid crystal panel having a liquid crystal layer arranged between a pair of transparent substrates with light, and is a red subsystem that emits red light. It is composed of a plurality of units including a blue subsystem that emits blue light, a green subsystem that emits green light, and a blue-green subsystem that emits blue-green light that is an intermediate color between blue and green. The colors have x and y values lower than the x and y values of the green subsystem in the xy chromaticity coordinates, and the red, green, blue, and turquoise subsystems have the xy chromaticity coordinates (0.65 ± 0.05, respectively). It is characterized by emitting colored light of (0.35 ± 0.05), (0.20 ± 0.10, 0.70 ± 0.10), (0.15 ± 0.05, 0.06 ± 0.05), and (0.05 ± 0.05, 0.60 ± 0.10).</p>

<p> According to the present invention, four sub-pixels are provided in a pixel, and each sub-pixel emits red, green, blue, and blue-green light, so that the pixel can emit light in a wide color gamut. .. Therefore, the display device of the present invention can display an image represented by a wide color gamut on the display as compared with the conventional display device. Similarly, the backlight for a liquid crystal display according to the present invention can display an image represented by a wide color gamut on the display.</p>

FIG. 1 is a schematic view showing a display device according to the first embodiment of the present invention. In the display device 11 according to the first embodiment, a large number of pixels 20 are arranged in the row direction m and the column direction n, respectively, to form a display area in a matrix. Each pixel 20 is formed, for example, in a substantially square shape, and four sub-pixels are arranged in a stripe shape in the row direction. As shown in Fig. 1, the four sub-pixels that make up pixel 20 are blue-green, red, green, and blue sub-pixels 10 from left to right in the figure._BG、10_R、10_G、10_BThey are arranged in the order of. The placement position of the sub-pixels within pixel 20 is the same for all pixels 20. Each sub-pixel forms a part of the image displayed on the display device 11 by emitting light by itself as described later.

FIG. 2 is a schematic diagram specifically showing the configuration of each pixel 20 in the present embodiment. The sub-pixels that make up each pixel 20 are each made up of a filter and an organic EL element. Each subpixel 10_BG、10_R、10_G、10_BBlue-green, red, green, blue organic EL elements that make up 23_BG、23_R、23_G、23_BAre organic EL devices that emit blue-green, red, green, and blue light, respectively. Organic EL element 23_BG、23_R、23_G、23_BWith each subpixel 10_BG、10_R、10_G、10_BConsists of turquoise, red, green, blue filters 24_BG、24_R、24_G、24_BIs a filter that transmits blue-green, red, green, and blue light, respectively.

Each organic EL element 23_BG、23_R、23_G、23_BIs a blue-green, red, green, and blue organic EL layer 31 on the upper surface side of the transparent substrate 30 as shown in FIG._BG、31_R、31_G、31_BIs sandwiched between a first electrode 32 (for example, an anode) and a second electrode 33 (for example, a cathode).

The first electrode 32 and the second electrode 33 are composed of a plurality of first electrode wires and second electrode wires parallel to each other, and the first electrode wire is provided so as to be orthogonal to each of the second electrode wires. Then, the organic EL layer is arranged between the positions where the first electrode line and the second electrode line intersect. With such a configuration, since the current is independently input to each of the organic EL layers constituting each sub-pixel, the emission brightness of each organic EL layer is controlled independently.

Each filter 24_BG、24_R、24_G、24_BEach organic EL element 23_BG、23_R、23_G、23_BIt is laminated on the upper surface of the transparent substrate 30 so as to correspond to. Filter 24_BG、24_R、24_G、24_BA smoothing layer 50 is provided on the upper surface of the smoothing layer 50, and the upper surface of the smoothing layer 50 is smoothed, and the first electrode (first electrode wire) 32 is coated on the smoothed upper surface. On the upper surface of the first electrode 32, each organic EL layer 31_BG、31_R、31_G、31_BIs coated, and a second electrode 33 is further coated on the upper surface of these organic EL layers.

The first electrode (first electrode wire) 32 is a transparent electrode, and is formed by using, for example, ITO (Indium Tin Oxide), ATO (Antimony Doped Tindioxide), ZnO (Zinc Oxide), and IZO (Indium Zinc Oxide). To. Further, the second electrode (second electrode wire) 33 is formed by using, for example, aluminum, and the smooth layer 50 is formed by, for example, SiO.₂Etc. are used as the material.

Red organic EL layer 31_RIs composed of, for example , a hole transport layer, a red light emitting layer, an electron transport layer, and an electron injection layer laminated in this order from the anode side. The hole transport layer is, for example, NPB (N, N'-di (naphthalene-1-yl) -N, N'-diphenyl-benzidine), TPD (N, N0-diphenyl-N, N0-bis (3-). It is formed by using methylphenyl) -1,10-diphenyl-4,40-diamine) and the like. The red light emitting layer is formed, for example, by doping a green light emitting material with a red dopant dye. As a green light emitting material, for example, Alq₃Alchelate compounds such as (triquinolinolate aluminum) are used. The red dopant dye is not particularly limited, but DCM2 (4-dicyanomethylene-2-methyl-6- (2- (2,3,6,7-tetra-hydro-1H, 5H-benzo)) [ ij] Kinoridine-8-yl) -4H-pyran), DCJTB (4- (dicyanomethylene) -2-t-butyl-6- (1,1,7,7-tetramethyldurolidyl-9-enyl) -4H-pyran), rhodamine 6G (rhodamine 6G), DCM (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran), etc. are used. The electron transport layer is, for example, Alq, which is also used in green luminescent materials.₃Alchelate compounds such as are used. The electron injection layer is formed by using, for example, Al: Li (aluminum lithium) or LiF.

Green organic EL layer 31_GIs configured by stacking a hole transport layer and a green light emitting layer in this order from, for example, the anode side. The hole transport layer is, for example, a red organic EL element 23._RSimilarly, it is formed by using NPB, TPD, etc. The green light emitting layer is formed by using a green light emitting material, and examples of the green light emitting material include the above-mentioned Alq.₃Alchelate compounds such as are used.

Blue organic EL layer 31_BIs configured by stacking a hole transport layer, a blue light emitting layer, and an electron transport layer in this order from, for example, the anode side. The hole transport layer is, for example, a red organic EL element 23._RSimilarly, it is formed by using NPB, TPD, etc. The blue light emitting layer is formed by using a blue light emitting material, and the blue light emitting material is a cyclopentadiene compound such as PPPP (1,2,3,4,5-pentaphenyl-1,3-cyclopentadiene). Is used. Also, for example, anthracene derivatives such as β-ADN (9,10-di (2-naphthyl) anthracene), TBADN (2-t-butyl-9,10-di (2-naphthyl) anthracene), or DPVBi (1, Styryl derivatives such as 4-bis (2,2-diphenylvinyl) biphenyl) and ADS082 (4,4-bis (diphenylvinylene) -biphenyl) are used. The blue light emitting layer may be doped with a blue dopant dye in the blue light emitting material, and the blue dopant dye is, for example, a perylene derivative such as perylene or tetra (t-butyl) perylene. The electron transport layer is, for example, Alq₃Alchelate compounds such as are used.

Blue-green organic EL layer 31_BGIs composed of, for example, a hole injection layer, a hole transport layer, a blue-green light emitting layer, and an electron injection layer laminated in this order from the anode side. The hole injection layer is formed using, for example, CuPc (copper phthalocyanine). The hole transport layer is, for example, a red organic EL element 23._RSimilarly, it is formed by using NPB, TPD, etc. The blue-green light emitting layer is formed by using, for example, BAlq (bis (2 methyl-8-quinolinolate) (paraphenylphenolate) aluminum). Further, the electron injection layer is formed by using, for example, Al: Li or LiF.

Each filter 24_BG、24_R、24_G、24_BIs formed as a filter that transmits blue-green, red, green, and blue light by appropriately selecting pigments, dyes, and the like.

Each organic EL element 23_BG、23_R、23_G、23_BWhen a current is passed between the anode and the cathode, holes are injected from the anode and electrons are injected from the cathode. The injected electrons and holes are blue-green, red, green, and blue organic EL layer 31._BG、31_R、31_G、31_BThen, each organic EL element 23_BG、23_R、23_G、23_BLight is emitted from blue-green, red, green, and blue, respectively. FIG. 7 shows an example of the emission spectrum of each light emitted from the organic EL element. The light emitted from the organic EL element also includes the light affected by the smooth layer and the transparent substrate, which will be described later. The light emitted from the organic EL element usually passes through a smooth layer and / or a transparent substrate, which will be described later, and then enters the filter. However, depending on the light transmission characteristics of the smooth layer or the transparent substrate, the spectrum of the light emitted from the organic EL element is affected, and the spectrum of the light emitted from the organic EL element itself and the spectrum of the light incident on the filter are different. It will not match. In consideration of such a thing, in the present invention, the light emitted from the organic EL element may be the light whose spectrum is influenced by the smooth layer or the transparent substrate.

Each organic EL element 23_BG、23_R、23_G、23_BThe blue-green, red, green, and blue light emitted from the filter 24 passes through the first electrode 32 and the smooth layer 50, respectively._BG、24_R、24_G、24_BIs incident on. Then, the light emitted from each organic EL element is emitted from each filter 24._BG、24_R、24_G、24_BIn, after the light having an unnecessary wavelength is appropriately removed, the light is transmitted through the transparent substrate 30 as blue-green, red, green, and blue light having high color purity, and then is irradiated to the outside. That is, each subpixel 10_BG、10_R、10_G、10_BEmits blue-green, red, green, and blue light with high color purity, respectively, by combining an organic EL element and a filter. Then, the light emitted from these sub-pixels is mixed to form one pixel of the display device, that is, one pixel of the image.

Where the red subpixel 10_RThe xy chromaticity coordinates of the light emitted from are located within the range of (0.65 ± 0.05, 0.35 ± 0.05). Blue subpixel 10_BThe xy chromaticity coordinates of the light emitted from are located within the range of (0.15 ± 0.05, 0.06 ± 0.05). Green subpixel 10_GThe xy chromaticity coordinates of the light emitted from are located at (0.20 ± 0.10, 0.70 ± 0.10). And turquoise subpixel 10_BGThe xy chromaticity coordinates of the light emitted from are located within the range of (0.05 ± 0.05, 0.60 ± 0.10), and the x and y values of the xy chromaticity coordinates are green subpixels 10._GLess than the x and y values of, respectively.

For the light of each of these sub-pixels, the current value input to the organic EL element is appropriately changed, and the emission intensity of the light of each sub-pixel is adjusted. Here each subpixel 10_BG、10_R、10_G、10_BCan emit light with the value of the xy chromaticity coordinates, so that each pixel 20 is the light of the chromaticity coordinates surrounded by the xy chromaticity coordinates by adjusting the emission intensity of the light of each subpixel. Can be emitted.

Red subpixel 10_RTo obtain the light of the above xy chromaticity coordinates, for example, the red subpixel 10_RThe wavelength at which the emission brightness of the light emitted from the light is maximized is located in the range of 600 to 650 nm, the emission peak is one, and the half width of the peak is set to 70 nm or less. Therefore, the red organic EL element 23_RIs the wavelength λ that maximizes the emission brightness of the emitted light by appropriately selecting the above materials._RMAXIs set to be located in any of the range of 600 to 650 nm, and the half width of the peak is set to 70 nm or less. Also, the red filter 24_RIs set so that the wavelength at which the maximum transmittance is located is 600 nm or more, the maximum transmittance is 60% or more in the range of 600 nm to 650 nm, and the transmittance is set to 15% or less in the wavelength range of 450 to 550 nm. Will be done. By combining such an organic EL element and a filter, subpixel 10_RIs capable of emitting light in the range of xy chromaticity coordinates (0.65 ± 0.05, 0.35 ± 0.05). In the present specification, the full width at half maximum is the so-called full width at half maximum, and means the width of the wave at 1/2 of the maximum value.

Green subpixel 10_GHowever, in order to obtain the light of the above xy chromaticity coordinates, the green subpixel 10_GThe wavelength at which the emission brightness of the light emitted from the light is maximized is located in the range of, for example, 510 to 550 nm, the emission peak is one, and the half width of the peak is set to 70 nm or less. Therefore, the green organic EL element 23_GIs the wavelength λ that maximizes the emission brightness by appropriately selecting the above materials._GMAXHowever, it is preferable that the width is set to be located in any of the range of 510 to 550 nm, and the half width of the peak is set to 70 nm or less. On the other hand, the green filter 24_GIs set so that, for example, the wavelength at which the maximum transmittance is located is located in the range of 510 to 550 nm, and the transmittance is set to 50% or more at least in the wavelength range of 510 to 550 nm. By combining such an organic EL element and a filter, subpixel 10_GCan emit light in the range of xy chromaticity coordinates (0.20 ± 0.10, 0.70 ± 0.10).

Blue subpixel 10_BTo obtain the light of the above xy chromaticity coordinates, for example, the blue subpixel 10_BThe wavelength at which the emission brightness of the light emitted from the light is maximized is located in the range of 430 to 470 nm, the emission peak is one, and the half width of the peak is set to 70 nm or less. Therefore, the blue organic EL element 23_BIs the wavelength λ that maximizes the emission brightness_BMAXIs set to be located in any of the 430-470 nm range. Also, the blue filter 24_BIs set so that the wavelength at which the maximum transmittance is located is within 430 to 470 nm, and the transmittance in the wavelength range of 430 to 470 nm is 50% or more. Further, for example, the transmittance of 540 nm or more is set to 20% or less. By combining such an organic EL element and a filter, subpixel 10_BIs capable of emitting light in the range of xy chromaticity coordinates (0.15 ± 0.05, 0.06 ± 0.05).

Blue-green subpixel 10_BGTo get the light in the above xy chromaticity coordinates, the turquoise subpixel 10_BGThe light emitted from has one emission peak, and the wavelength at which the emission brightness is maximized is the green subpixel 10._GIt must be shorter, for example in the range of 490-510 nm. Here, the blue-green organic EL element 23_BGWhen BAlq is used as the light emitting layer as described above, for example, a blue-green organic EL element 23_BGThe light emitted from is seen to have two emission peaks, one of which is the peak at which the emission brightness is maximized, and its peak wavelength λ._BGP1Is located in the range of 450 to 470 nm. Also, the other peak λ_BGP2Is the wavelength λ_BGP1The emission brightness of the light is smaller than that of the light of, and the wavelength λ_BGP2Is the wavelength λ_BGP1It is longer and is located in the range of 480 to 500 nm.

When such an organic EL element is used, the blue-green subpixel 10_BGIn order for the wavelength that maximizes the emission brightness of the light to be located in the range of 490 to 510 nm, the blue-green filter 24_BGIs one of the peak wavelengths λ_BGP1It must absorb a lot of light in the vicinity. Therefore, in the present embodiment, the blue-green filter 24_BGIs set so that the transmittance in the wavelength range of at least 430 to 470 nm is 20% or less, the wavelength of the maximum transmittance is set to 490 to 510 nm, and the maximum transmittance is set to at least 60% or more. Will be done. Also, the turquoise filter 24_BGThe wavelength that maximizes the transmittance is the blue filter 24._BLarger than the wavelength at which the transmittance of is maximum, and the green filter 24_GIs smaller than the wavelength at which the transmittance of is maximum. Such a turquoise filter 10_BGAnd turquoise organic EL element 23_BGBy combining, in this embodiment, the blue-green subpixel 10_BGEmits light with xy chromaticity coordinates (0.05 ± 0.05, 0.60 ± 0.10), and its x and y values are lower than the x and y values of the green subpixel, respectively.

As described above, in the present embodiment, four sub-pixels are provided in the pixel 20, and each sub-pixel emits light located at the xy chromaticity coordinate, so that the pixel 20 has a wide color gamut. It is possible to emit light. Therefore, the display device of the present embodiment can display an image represented by a wide color gamut on the display as compared with the conventional display device.

In the present embodiment, the red, green, blue, and turquoise subpixels are xy chromaticity coordinates (0.65,0.35), (0.20,0.70), (0.15,0.06), and (0.05,0.60), respectively. It is preferable to emit the colored light of. By emitting light of such xy chromaticity coordinates by each sub-pixel, each pixel can display a color of xy chromaticity coordinates that a person can perceive biologically with high sensitivity.

Further, the sub-pixels in the pixel 20 are not limited to the case where they are arranged in a stripe shape as shown in FIG. 1, and may be arranged as shown in FIG. 3, for example. That is, subpixel 1010_R、10_G、10_BG、10_BAre each formed in a substantially square shape, and one pixel 20 may be composed of four sub-pixels, two in the row direction m and two in the column direction n. The four sub-pixels 10 that make up pixel 20 are each sub-pixel 10 as shown in FIG._R、10_G、10_BG、10_BAnd within pixel 20, subpixel 10_G、10_BGAre placed diagonally. The arrangement position of the sub-pixel 10 in the pixel 20 is the same in all the pixels 20.

Next, the second embodiment will be described. In the display device according to the first embodiment, the organic EL element is used as a self-luminous light source, but in the second embodiment, the organic EL element is used as a backlight of a liquid crystal display.

FIG. 4 is a perspective view schematically showing the liquid crystal display according to the present embodiment. As shown in FIG. 4, the liquid crystal display 210 includes a backlight 220 and a liquid crystal panel 100.

The liquid crystal panel 100 is formed between the first substrate 101 provided on the lower side in the drawing and the second substrate 102 provided on the upper side in the drawing, in order from the lower side, the liquid crystal color filter 103 and the first liquid crystal electrode. A portion 104, a liquid crystal layer 110, and a second liquid crystal electrode portion 105 are arranged and configured. A first polarizing filter 111 is provided on the lower surface side of the first substrate 101 in the drawing, and a second polarizing filter 112 is provided on the upper surface side of the second substrate 102. The first and second substrates 101 and 102 are transparent substrates and are made of plastic, glass substrate, or the like.

The first and second liquid crystal electrode portions 104 and 105 are transparent electrodes and are composed of a plurality of first electrode wires 104a and second electrode wires 105b parallel to each other, and each of the first electrode wires 104a is a transparent electrode. It is provided so as to be orthogonal to the second electrode line 105b. Then, at each position where the first electrode line 104a and the second electrode line 105b intersect, each portion of the liquid crystal layer 110 laminated between the first electrode line 104a and the second electrode line 105b has one pixel P. Configure. In each pixel P of the liquid crystal layer 110, the arrangement state of the molecules is changed by the voltage applied from the first electrode line 104a and the second electrode line 105b.

The liquid crystal color filter 103 is configured by arranging a liquid crystal red filter 103R, a liquid crystal green filter 103G, and a liquid crystal blue filter 103B in a striped pattern. The widths of the liquid crystal filters 103R, 103G, and 103B are formed so as to correspond to the width of one pixel, and extend along the first electrode line 104a, respectively.

FIG. 5 is a cross-sectional view of the backlight 220. Hereinafter, the configuration of the backlight will be described with reference to FIGS. 4 and 5. As shown in FIG. 4, the backlight 220 is configured by providing a plurality of EL units 221 on a transparent substrate 230.

Each EL unit 221 is a blue-green, red, green, blue EL subunit 222 as shown in FIG._BG、222_R、222_G、222_BConsists of. Each EL subunit 222_BG、222_R、222_G、222_BAre blue-green, red, green, and blue organic EL elements 223, respectively._BG、223_R、223_G、223_BAnd turquoise, red, green, blue filters 224_BG、224_R、224_G、224_BAre combined and configured.

Each filter 224_BG、224_R、224_G、224_BEach organic EL element 223_BG、223_R、223_G、223_BIt is laminated on the upper surface of the transparent substrate 230 so as to correspond to. Filter 224_BG、224_R、224_G、224_BA smoothing layer 250 is provided on the upper surface of the smoothing layer 250 as in the first embodiment, and the upper surface of the smoothing layer 250 is smoothed. On the smoothed upper surface, a first electrode (first electrode wire) is provided. 232 is coated.

Each organic EL element 223_BG、223_R、223_G、223_BAre laminated on the first electrode 232 (for example, the anode), respectively, as shown in FIG. 5, and the respective blue-green, red, green, and blue organic EL layers 231 are laminated._BG、231_R、231_G、231_BIs sandwiched between a first electrode 232 (for example, an anode) and a second electrode 233 (for example, a cathode).

The organic EL layer 231 constituting the EL unit 221_BG、231_R、231_G、231_BAre arranged in stripes in the EL unit 221 as in the first embodiment. The EL unit 221 is also arranged innumerably in the row direction m and the column direction n as in the first embodiment. The arrangement position of each organic EL layer in the EL unit 221 may be the same or different in all the units 221. Further, as shown in FIG. 3, one EL unit 221 may be composed of four subunits arranged two in the row direction m and two in the column direction n.

Each organic EL layer 231_BG、231_R、231_G、231_BThe occupied area on the first electrode 232 of the EL unit 221 is larger than the area of one pixel P of the liquid crystal layer 110, for example, the occupied area of the EL unit 221 on the first electrode 232 is at least four pixels of the liquid crystal layer 110 or more. Occupy an area.

In addition, each organic EL layer 231_BG、231_R、231_G、231_B, 1st and 2nd electrodes 232, 233, and filter 224_BG、224_R、224_G、224_BSince the configuration of is the same as that of the first embodiment, the description thereof will be omitted. However, although the first and second electrodes 32 and 33 in the first embodiment are each divided into a plurality of electrode lines, the first and second electrodes 232 and 233 according to the second embodiment are plural. It may be a single electrode without being divided into the electrode wires of. This is because the organic EL element is used for the backlight in the second embodiment, so that it is not necessary to adjust the current on / off and the current amount for each EL subunit (and EL unit).

Hereinafter, the operation of the liquid crystal panel according to the present embodiment will be described with reference to FIGS. 4 and 5. A current is passed between the first and second electrodes 232 and 233, and each organic EL layer 231_BG、231_R、231_G、231_BWhen holes and electrons are injected into, the electrons and holes are recombined in each EL layer, and each organic EL layer 231_BG、231_R、231_G、231_BBlue-green, red, green, and blue light is emitted from. The emitted light passes through the first electrode 232 and the smoothing layer 250, respectively, and is filtered through the filter 224._BG、224_R、224_G、224_BIs incident on. And each color filter 224_BG、224_R、224_G、224_BAfter the light having an unnecessary wavelength is appropriately removed, the light is transmitted to the outside as blue-green, red, green, and blue light having high color purity through the transparent substrate. That is, each EL subunit 222_BG、222_R、222_G、222_BEmits blue-green, red, green, and blue light with high color purity to the outside.

Each EL subunit 222_BG、222_R、222_G、222_BThe light emitted from the light is diffused light, and the blue-green, red, green, and blue lights are mixed and incident on the liquid crystal panel 100 as white light. The white light incident on the liquid crystal panel 100 passes through the second polarizing filter 112 and the second substrate 102 and is introduced into the liquid crystal layer 110 as polarized light. The introduced polarized light is modulated by the liquid crystal layer 110 having a different molecular arrangement state for each pixel P to obtain a predetermined polarized light, and then becomes red, green, or blue light by the liquid crystal color filter 103. These red, green, and blue lights pass through the first substrate 101 and then are transmitted or absorbed by the first polarizing filter 111. The light transmitted through the first polarizing filter 111 is emitted to the outside to form an image.

Each organic EL layer 231_R、231_G、231_BG、231_BThe light emitted from is light having the xy chromaticity coordinates, and the light obtained by mixing these lights has a very wide color gamut as described above. Therefore, the liquid crystal display 210 in the present embodiment can display an image having good color reproducibility. Further, in the present embodiment, the liquid crystal color filter 103 is provided with only three colors, but similarly to the backlight 220, a blue-green filter may be provided in addition to the red, green and blue filters.

In the first and second embodiments, each subunit and each subunit is composed of a combination of an organic EL element and a filter, but when the color purity of the organic EL element is high, the filter is omitted. You may. Also, in some cases, the filter may be omitted for subpixels of a particular color.

In the first embodiment, each filter 24_BG、24_R、24_G、24_BIs arranged between the electrode and the substrate, but may be arranged on the lower surface side of the transparent substrate 30 as shown in FIG. However, each filter 24_BG、24_R、24_G、24_BIs the same as in this embodiment, each organic EL element 23_BG、23_R、23_G、23_BIt is provided to correspond to. Further, in FIG. 6, the smooth layer is not provided, and the first electrode 32 is directly laminated on the transparent substrate 30. Similarly, in the second embodiment, the filter 224_BG、224_R、224_G、224_BMay be provided on the lower surface side of the transparent substrate.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the examples described below. In the examples, the xy chromaticity coordinates of each emission color when the organic EL element of each color and the color filter were combined were confirmed.

(1) Red (A) Organic EL element First, a red filter is provided on a transparent substrate made of glass, and SiO is placed on the red filter.₂A smooth layer made of was laminated. Then, a transparent electrode (anode) made of ITO and a hole transport layer made of NPB are laminated on this smooth layer by vacuum vapor deposition in this order, and then DCJTB is placed on the green light emitting material Alq.₃The red light emitting layer doped with the above was laminated. The red light emitting layer is Alq, which is a green light emitting material.₃DCJTB, which is a red dopant dye, was vacuum-deposited at the same time. At this time, DCJTB is Alq₃Was doped by 1% by weight. On top of the red light emitting layer, Alq₃An electron transport layer made of LiF, an electron injection layer made of LiF, and a cathode made of aluminum were laminated in this order by vacuum deposition to obtain a red organic EL device. The thickness of each layer is 0.7 mm for the transparent substrate, 400 nm for the smooth layer, 125 nm for the anode, 60 nm for the hole transport layer, 40 nm for the red light emitting layer, 40 nm for the electron transport layer, 5 nm for the electron injection layer, and 5 nm for the cathode. It was 100 nm. The emission spectrum of the light emitted from the organic EL element is shown in FIG. In FIG. 7, the horizontal axis represents the wavelength (nm), the vertical axis represents the emission brightness, and the emission brightness is expressed with the maximum value of each organic EL element as 1.

As shown in FIG. 7, the light emitted from the red organic EL element consists of one emission peak and has a wavelength λ that maximizes the emission brightness._RMAXWas 620 nm. When the maximum value of the emission brightness was 1, the emission brightness was halved or more at 590 to 650 nm, that is, the half width of the emission peak was 60 nm.

(B) Color filter As the red filter, 182 Light Red (trade name) manufactured by Lee Filter Co., Ltd. was used. The spectral characteristics of this filter are shown in FIG. In FIG. 8, the horizontal axis represents the wavelength (nm) and the vertical axis represents the transmittance (× 100%). As shown in FIG. 8, in the red filter, the transmittance was 50% or more at 585 to 700 nm and 80% or more at 600 to 700 nm. The transmittance reached its maximum at 645 nm. On the other hand, the transmittance was 10% or less in the wavelength range of 450 to 550 nm.

FIG. 12 shows the chromaticity coordinate xy of the light when the light from the organic EL element is taken out through the color filter and the transparent substrate by combining the organic EL element and the color filter. In FIG. 12, the horizontal axis is X and the vertical axis is Y. As shown in FIG. 12, the chromaticity coordinate xy of red light was (0.66, 0.34). In FIG. 12, for reference, the RGB values standardized in the NTSC system and the RGB values standardized in sRGB are also shown by dotted lines and alternate long and short dash lines, respectively. Further, in this embodiment, the smooth layer and the transparent substrate used have flat transmission characteristics that do not change the spectrum with respect to the incident light.

(2) Green (A) Organic EL element First, a green filter is provided on a transparent substrate made of glass, and SiO is placed on the green filter.₂A smooth layer made of was laminated. Then, on the smooth layer, a transparent electrode (anode) made of ITO, a hole transport layer made of NPB, and Alq₃A green light emitting layer made of and a cathode made of aluminum were laminated in this order by vacuum deposition to obtain a green organic EL device. The thickness of each layer was 0.7 mm for the transparent substrate, 400 nm for the smooth layer, 125 nm for the anode, 40 nm for the hole transport layer, 40 nm for the green light emitting layer, and 100 nm for the cathode. The emission spectrum of the light emitted from the organic EL element is shown in FIG.

As shown in FIG. 7, the light emitted from the green organic EL element consists of one emission peak and has a wavelength λ that maximizes the emission brightness._GMAXWas 530 nm. When the maximum value of the emission brightness was 1, the emission brightness was halved or more at 500 to 565 nm, that is, the half width of this peak was 65 nm.

(B) Color filter As the green filter, 122 Fern Green (trade name) manufactured by Lee Filter Co., Ltd. was used. The spectral characteristics of this filter are shown in FIG. In FIG. 9, the horizontal axis represents the wavelength (nm) and the vertical axis represents the transmittance (× 100%). As shown in FIG. 9, in the green filter, the transmittance became maximum at 520 nm and the transmittance became 70% or more at 500 to 550 nm. Further, at 490 to 565 nm, the transmittance was more than 1/2 of the maximum transmittance, that is, the half width was 75 nm.

When the organic EL element and the color filter were combined and the light from the organic EL element was taken out through the color filter and the transparent substrate, the chromaticity coordinate xy of the light was (0.21, 0.70) (FIG. 12). reference).

(3) Blue (A) Organic EL element First, a blue filter is provided on a transparent substrate made of glass, and SiO is placed on the blue filter.₂A smooth layer made of was laminated. Then, on the smooth layer, a transparent electrode (anode) made of ITO, a hole transport layer made of TPD, a blue light emitting layer made of PPCP, and Alq.₃An electron transport layer made of aluminum and a cathode made of aluminum were laminated in this order by vacuum deposition to obtain a blue organic EL device. The thickness of each layer was 0.7 mm for the transparent substrate, 400 nm for the smooth layer, 125 nm for the anode, 40 nm for the hole transport layer, 30 nm for the blue light emitting layer, 30 nm for the electron transport layer, and 100 nm for the cathode. The emission spectrum of the light emitted from the organic EL element is shown in FIG.

As shown in FIG. 7, the light emitted from the blue organic EL element consists of one emission peak and has a wavelength λ that maximizes the emission brightness._BMAXWas 445 nm. When the maximum value of the emission brightness was 1, the emission brightness was halved or more at 415 to 475 nm, that is, the half width of the peak was 60 nm.

(B) Color filter As the blue filter, 183 Moonlight Blue (trade name) manufactured by Lee Filter Co., Ltd. was used. The spectral characteristics of this filter are shown in FIG. In FIG. 10, the horizontal axis represents the wavelength (nm) and the vertical axis represents the transmittance (× 100%). As shown in FIG. 10, in the blue filter, the transmittance became maximum at 470 nm and the transmittance became 70% or more at 435 to 495 nm. In addition, the transmittance was 50% or more at 405 to 515 nm, and the transmittance at 540 nm or more was 20% or less.

When the above organic EL element and the color filter were combined and the light from the organic EL element was taken out through the color filter and the transparent substrate, the chromaticity coordinate xy of the light was (0.15,0.05) (see FIG. 12). ..

(4) Blue-green (A) Organic EL element First, a blue-green filter is provided on a transparent substrate made of glass, and SiO is placed on the blue-green filter.₂A smooth layer made of was laminated. Then, on the smooth layer, a transparent electrode (anode) made of ITO, a hole injection layer made of CuPc, a hole transport layer made of NPB, a blue-green light emitting layer made of BAlq, and an electron injection made of LiF are placed on a transparent substrate. A cathode composed of layers and aluminum was laminated in this order by vacuum deposition to obtain a blue-green organic EL device. The thickness of each layer is 0.7 mm for the transparent substrate, 400 nm for the smooth layer, 125 nm for the anode, 10 nm for the hole injection layer, 30 nm for the hole transport layer, 40 nm for the blue-green light emitting layer, and 5 nm for the electron injection layer. The cathode was 100 nm. The emission spectrum of the light emitted from the blue-green organic EL element is shown in FIG.

As shown in FIG. 7, the light emitted from the blue-green organic EL element has two emission peaks, one of which is the peak at which the emission brightness is maximized, and its peak wavelength λ._BGP1Was 460 nm. The emission brightness of the other peak is 0.47, where 1 is the emission brightness of one peak, and its wavelength λ._BGP2Was 490 nm.

(B) Color filter As the blue-green filter, 124 Dark Green (trade name) manufactured by Lee Filter Co., Ltd. was used. The spectral characteristics of this filter are shown in FIG. As shown in FIG. 11, in the blue-green filter, the wavelength at which the transmittance was maximized was 505 nm. In this filter, the transmittance was 80% or more at 495 to 535 nm, and the transmittance was suppressed to 10% or less at 430 to 485 nm.

When the organic EL element and the color filter were combined and the light from the organic EL element was taken out through the color filter and the transparent substrate, the chromaticity coordinate xy of the light was (0.05, 0.59) (FIG. 12). reference).

From the above examples, by combining the above-mentioned organic EL element and the color filter, four subpixels (or subunits) can be converted into (0.05,0.59), (0.66,0.34), (0.21,0.70), and (0.21,0.70). It can be understood that 0.15,0.05) light can be emitted. That is, the display device (or the backlight for the liquid crystal display) according to the embodiment can express the color surrounded by the xy chromaticity coordinates by combining these organic EL elements and the color filter.

<figref num="1">It is a figure which showed typically the arrangement of each pixel of the display device which concerns on 1st Embodiment.</figref><figref num="2">It is sectional drawing which shows each pixel schematically.</figref><figref num="3">It is a figure which showed typically the arrangement of each pixel of the display device which concerns on a modification.</figref><figref num="4">It is a perspective view which shows typically the liquid crystal display which concerns on 2nd Embodiment.</figref><figref num="5">It is a schematic cross-sectional view of the backlight for a liquid crystal display.</figref><figref num="6">It is sectional drawing which shows the deformation example of each pixel schematically.</figref><figref num="7">It is a graph which shows the chromaticity distribution of each organic EL element in an Example.</figref><figref num="8">It is a graph which shows the chromaticity distribution of a red filter in an Example.</figref><figref num="9">It is a graph which shows the chromaticity distribution of the green filter in an Example.</figref><figref num="10">It is a graph which shows the chromaticity distribution of a blue filter in an Example.</figref><figref num="11">It is a graph which shows the chromaticity distribution of the blue-green filter in an Example.</figref><figref num="12">It is a graph which shows the chromaticity coordinate when the color filter of each color in an Example and an organic EL element are combined.</figref>

Code description

10_BG Blue-green subpixel 10_R Red subpixel 10_G Green subpixel 10_B Blue subpixel 20 pixels 23_BG、223_BG Blue-green organic EL element 23_R、223_R Red organic EL element 23_G、223_G Green organic EL element 23_B、223_B Blue organic EL element 24_BG、224_BG Blue-green filter 24_R、224_R Red filter 24_G、224_G Green filter 24_B、224_B Blue filter 31_BG、231_BG Blue-green organic EL layer 31_R、231_R Red organic EL layer 31_G、231_G Green organic EL layer 31_B、231_B Blue organic EL layer 221 EL unit 222_BG Blue-green EL subunit 222_R Red EL subunit 222_G Green EL subunit 222_B Blue EL subunit