A planar light source

IS 2 148 997 T3

DESCRIPTION

Light emitting device and screen.

Background of the invention

Field of the invention

The present invention relates to a light emitting diode used in a display equipped with LEDs, a black light source, traffic signs, railway signs, lighting switches, indicators, etc.

More particularly, it relates to a light emitting device (LED) comprising phosphor and converting the wavelength of light emitted by a light emitting component and emitting light, and a display device using the light emitting device. light.

Description of Related Art

A light-emitting diode is a compact element that emits light-colored light with high efficiency. It is also free from problems such as burnout and has good initial excitation characteristics, high resistance to vibration and high durability, ensuring repetitive On / Off operations, since it is a semiconductor element. Therefore, it has been widely used in such applications as indicators and light sources. Recently, RGB type color diodes (red, green and blue colors) with ultra high luminance and high efficiency have been developed and large LED displays using such light emitting diodes have been put into use. LED displays can be operated with less energy and have good light, weight and long life characteristics, thus it is expected that they will be used more widely in the future.

Recently, various attempts have been made to make white light sources through the use of light emitting diodes. Since the light-emitting diode has a favorable emission spectrum for generating monochromatic light, producing a white light source requires arranging three red, green, and blue light-emitting components closely to each other, while diffusing and mixing the light emitted by the light sources. themselves. When generating white light with such a configuration there has been a problem that white light of the desired hue cannot be generated due to variations in hue, luminance and other factors of the light emitting component. Also, when the light-emitting components are made of different materials, the electrical energy required for their excitation differs from one light-emitting diode to the other, making it necessary to apply different voltages to the different light-emitting components, which leads to a circuit full exciter. In addition, since light-emitting components are semiconductor light-emitting components, the color tone is subject to variations due to differences in temperature characteristics, time changes and operating media, or unevenness in color may result due to the inability to uniformly mix the light emitted by the light-emitting components. Thus, light emitting diodes are effective as light emitting devices to generate individual colors, although a satisfactory light source capable of emitting white light through the use of light emitting components has not been obtained to date.

In order to solve these problems, the present applicant previously developed light-emitting diodes that convert the color of the light emitted by the light-emitting components by means of a fluorescent material disclosed in Japanese patents JP-A-5-152609, JP-A-7-99345, JP-A7-176794 and JP-A-8-7614. The light emitting diodes disclosed in said publications are such that by using light emitting components of one type they are capable of generating white and other colored light and are constituted as follows.

The light emitting diode disclosed in the previous publications is manufactured by assembling a light emitting component, which has a large energy gap between bands of the light emitting layer, in a cup provided at the tip of a conductive frame and having a fluorescent material that absorbs the light emitted by the light emitting component and emits light of a different wavelength from the absorbed light (wavelength conversion) contained in a resin mold covering the light emitting component.

The light emitting diode disclosed in the manner described above capable of emitting white light by mixing the light from a plurality of sources can be manufactured by using a light emitting component capable of emitting blue light and casting the light emitting component with a resin. It includes a fluorescent material that absorbs the light emitted by the blue light emitting diode and emits yellowish light.

IS 2 148 997 T3

However, conventional light emitting diodes have problems such as deterioration of the fluorescent material leading to deviation of the color tone and darkening of the fluorescent material, resulting in decreased efficacy of the emitted light. In the present reference to darkening, in the case of use of an inorganic fluorescent material such as (Cd, Zn) S type fluorescent material, for example, part of the metallic elements that make up the fluorescent material precipitate or change their properties leading to the coloration, or in the case of using a fluorescent organic material, the coloration due to the breaking of the double bond of the molecule. Especially when a light emitting component made of a semiconductor with a large interband energy gap is used to improve the conversion efficiency of the fluorescent material (i.e., the energy of light emitted by the semiconductor is increased and the photon number that have energy above a threshold that can be absorbed by the fluorescent material is increased, resulting in more light being absorbed), or the amount of consumption of the fluorescent material decreases (that is, the fluorescent material is irradiated with relatively higher energy), the energy of the light absorbed by the fluorescent material inevitably increases resulting in a more significant degradation of the fluorescent material. The use of the light emitting component with high light emitting intensity for an extended period of time causes additional significant degradation of the fluorescent material.

In addition, the fluorescent material arranged in the vicinity of the light-emitting component can be exposed to a high temperature, so that it can increase the temperature of the light-emitting component and the heat transmitted from the external environment (for example sunlight in case devices used abroad).

In addition, some fluorescent materials are subject to accelerated deterioration due to the combination of moisture introduced from outside or introduced during the production process, light and heat transmitted from the light emitting component.

When it comes to an ionic property organic dye, the electric field created by the direct current at the speed of the chip can cause electrophoresis, resulting in a change in color tone.

EP-A-0209942 discloses low pressure mercury vapor discharge lamps. Said lamps have a filling comprising mercury and a rare element gas and a luminescent layer comprising a luminescent material whose emission was mainly between 590-630 nm and 520-565 nm. The light emitted by the discharge lamp was in a wavelength range that is almost totally invisible and has to be transformed by the luminescent layer to become visible. The lamp is furthermore provided with an absorbing layer comprising a luminescent aluminate activated by trivalent cerium and having a garnet crystal structure. Such a lamp cannot be produced in the form of a simple, small, light and inexpensive device.

Summary of the invention

Therefore, an object of the present invention is to solve the problems described above and to provide a light emitting device that experiences only extremely low levels of deterioration in the intensity of the emitted light, an efficient light emission and color exchange. for long time of use with high luminance.

The present applicant completed the present invention by research based on the assumption that the light emitting device with a light emitting component and a fluorescent material must meet the following requirements to achieve the above-mentioned object.

(1) The light-emitting component must be capable of emitting high-luminance light with light-emitting characteristics that are stable over a long period of use.

(2) The fluorescent material supplied in the vicinity of the high luminance light emitting component should show excellent resistance to light and heat, so that the characteristics thereof do not change even when used for an extended period of time while exposed to the high intensity light emitted by the light emitting component (particularly the fluorescent material supplied in the vicinity of the emitting component). light was exposed to light of radiation intensity as high as approximately 30 to 40 times that of sunlight according to our estimate, and requires longer duration of exposure to light since a high luminance light emitting component is used).

ES 2 148 997 T3 (3) With regard to the relationship with the light-emitting component, the fluorescent material must be capable of absorbing high monochromatic light emitted by the light-emitting component with high efficiency and emitting light of a length of wave different from that of the light emitted by the light emitting component.

Thus, the present invention provides a light emitting device according to claim

1.

The semiconductor component of nitride (generically represented by the chemical formula and In_iGajAl_kN, where 0 <i, 0 <j, 0 <ke i + j + k = 1)) mentioned above contains various materials including InGaN and GaN doped with various impurities.

The aforementioned phosphorus contains various materials in the form described above, including Y3Al5O12: Ce and Gd3In5O12: Ce.

Since the light emitting device of the present invention uses the light emitting component made of a semiconductor nitride compound capable of emitting light with high luminance, the light emitting device is capable of emitting light with high luminance. Furthermore, the phosphor used in the light emitting device has excellent lightfastness, so that the fluorescent properties of the device undergo less change even when used for an extended period of time while exposed to high intensity light. This makes it possible to reduce the degradation of its properties during a long period of use and to reduce the deterioration due to the high intensity light emitted by the light emitting component, as well as by extraneous light (sunlight that includes ultraviolet light, etc. ) during outdoor use to thereby provide a light emitting device that experiences less color change and less drop in luminance. The light emitting device of the present invention can also be used in such applications that require response speeds as high as 120 ns, for example, since the phosphor used inside allows it to glow only for a short period of time.

In the light emitting device of the present invention, the highest emission peak of the light emitting component is set within the range of 400 nm to 530 nm and the main emission wavelength of the phosphor is set to be greater than the main emission peak of the light emitting component. The above makes it possible to efficiently emit white light.

Furthermore, in the light emitting device of the present invention, it is considered preferable that the light emitting layer of the light emitting component contains a gallium nitride semiconductor containing In. Other preferred features of the embodiments of the present invention are described in the dependent claims.

The light emitting device according to an embodiment of the present invention comprises a substantially rectangular optical guide plate supplied with the light emitting component mounted on a front side face thereof and, with the exception of a main surface, the others are covered. by a reflective material, wherein the light emitted by the light emitting component is converted to planar light by the phosphor and the optical guide plate to be emitted from the main surface of the optical guide plate. In said embodiment, the phosphor was preferably contained in a coating material mounted on said front side face and in direct contact with the light-emitting component or installed on a main surface of the ooptic guide plate not covered by the material. reflector.

The LED display device according to the present invention has an LED display device comprising the light emitting devices of the present invention arranged in a matrix and a driver circuit that drives the LED display device to display the data entered therein. Such a configuration makes it possible to provide a relatively low cost LED display device that is capable of displaying with high definition and less color unevenness due to viewing angle.

Genoerically, a fluorescent material that absorbs light of a short wavelength and emits light of a long wavelength has higher efficiency than a fluorescent material that absorbs light of a high wavelength and emits light of a short wavelength. It is preferable to use a light emitting component that emits visible light than a light emitting component that emits ultraviolet light that degrades the resin (mold material, coating material, etc.). Thus, for the light emitting diode of the present invention, in order to improve the light emission efficiency and ensure long life, the main emission peak of the light emitting component is set within a range of length

ES 2 148 997 T3 short wave 400 nm to 530 nm in the visible region of light and the main emission wavelength of the phosphor is set to be longer than the main emission peak of the light emitting component. With this configuration, since the light converted by the fluorescent material has a longer wavelength than that of the light emitted by the light emitting component, it will not be absorbed by the light emitting component even when the light emitting component is irradiated with light that has been reflected and converted by the fluorescent material (since the energy of the converted light is less than the energy jump between bands. Thus, in an embodiment of the present invention, the light that has been reflected by the fluorescent material or the like is reflected by the cup in which the light-emitting component is mounted, making possible a higher emission efficiency. .

Brief description of the drawings

Figure 1 is a schematic sectional view of a conductive type light emitting diode according to the embodiment of the present invention.

Figure 2 is a schematic sectional view of a tip-type light emitting diode according to the second embodiment of the present invention.

Figure 3A is a graph showing the excitation spectrum of the cerium activated garnet fluorescent material used in the first embodiment of the present invention.

Figure 3B is a graph showing the emission spectrum used in the first embodiment of the present invention.

Figure 4 is a graph showing the emission spectrum of the light emitting diode of the first embodiment of the present invention.

FIG. 5A is a graph showing the excitation spectrum of the yttrium-alumina-cerium-activated garnet fluorescent material used in the second embodiment of the present invention.

Figure 5B is a graph showing the emission spectrum of the fluorescent material used in the second embodiment of the present invention.

Figure 6 shows the chromaticity diagram of the light emitted by the light emitting diode of the second embodiment, where points A and B indicate the colors of the light emitted by the light emitting components and points C and D indicate the colors of the light emitted by the two types of phosphor.

Figure 7 is a schematic sectional view of the planar light source according to another embodiment of the present invention.

Figure 8 is a schematic sectional view of another planar light source different from that of Figure 7.

Figure 9 is a schematic sectional view of another planar light source different from those shown in Figures 7 and 8.

Figure 10 is a block diagram of a display device that is an application of the present invention.

Figure 11 is a plan view of the LED display unit of the display device of Figure 10.

Figure 12 is a plan view of the LED display device in which a pixel was made up of 4 light-emitting diodes including the light-emitting diode of the present invention and those that emit RGB colors.

Figure 13A shows the result of the useful life test of the light emitting diodes of Example 1 and Comparative Example 1, showing the result at 25 C and Figure 13B shows the result of the useful life test of the light emitting diodes from Example 1 and Comparative Example 1, showing the result at 60 ° C and 90% relative humidity.

IS 2 148 997 T3

Figure 14A shows the result of the performance test under climatic conditions of example 9 and comparative example 2 showing the change in luminance retention ratio with time and Figure 14B shows the result of the performance test under climatic conditions of example 9 and from comparative example 2 showing the change showing the color tone before and after the test.

Figure 15A shows the results of the reliability test of Example 9 and Comparative Example 2 showing the relationship between luminance retention and time, and Figure 15B is a graph showing the relationship between color tone and time.

Figure 16 is a chromaticity diagram showing the ranges of color tone that can be obtained with the light emitting diode that combines the fluorescent materials shown in Table 1 and the blue LED that has a peak wavelength at 465 nm. .

Figure 17 is a chromaticity diagram showing the change in color tone when the concentration of the fluorescent material is changed in the light emitting diode combining the fluorescent materials shown in Table 1 and the blue LED with a wavelength 465 nm peak.

Figure 18A shows the emission color spectrum of the phosphor (Y^0,6Gd0.4) 3Al5O12: Ce from example 18A.

Figure 18B shows the emission spectrum of the light emitting component of Example 18B with a peak emissioan wavelength of 460 nm.

Figure 18C shows the emission spectrum of the light emitting diode of Example 2.

Figure 19A shows the emission spectrum of phosphorus (Y0.2Gd0.8) 3Al5O12: Ce from example 5.

Figure 19B shows the emission spectrum of the light emitting component of Example 5 with the wavelength of the emission peak of 450 nm.

Figure 19C shows the emission spectrum of the light emitting diode of Example 5.

Figure 20A shows the emission spectrum of the Y3Al5O12: Ce phosphor from Example 6.

Figure 20B shows the emission spectrum of the light emitting component of Example 6 with the emission peak of wavelength 450 nm.

Figure 20C shows the emission spectrum of the light emitting diode of Example 6.

Figure 21A shows the emission spectrum of phosphor Y3 (Al0.5Ga0.5) 5O12: Ce of the seventh embodiment of the present invention.

Figure 21B shows the emission spectrum of the light-emitting component of Example 7 with a wavelength emission peak of 450 nm.

Figure 21C shows the emission spectrum of the light emitting diode of Example 7.

Figure 22A shows the emission spectrum of the phosphor (Y0.8Gd0.2) 3Al5O12: Ce from example 11.

Figure 22B shows the emission spectrum of the phosphor (Y0.4Gd0.6) 3Al5O12: Ce from example 11.

Figure 22C shows the emission spectrum of the light emitting component of Example 11 with an emission peak of wavelength of 470 nm.

Figure 23 shows the emission spectrum of the light emitting diode of Example 11.

Detailed description of the preferred embodiments

Referring now to the accompanying drawings, preferred embodiments of the present invention will be described below.

IS 2 148 997 T3

A light-emitting diode 100 of Figure 1 is a conductive-type light-emitting diode having a conductive mount 105 and an inner conductor 106, wherein the light-emitting component 102 is installed on a cup 105a of the conductive mount 105. and the cup 105a which is filled with a coating resin 101 containing a specified phosphor to cover the light emitting component 102 and is cast in resin. An electrode n and an electrode p of the light emitting component 102 are connected to the conductive mount 105 and the inner conductor 106, respectively, by means of wires 103.

In the light emitting diode constituted as described above, part of the light emitted by the light emitting component (LED chip) 102 (hereinafter referred to as LED light) excites the phosphor contained in the coating resin 101 to generate a fluorescent light with a different wavelength from that of LED light, so that the fluorescent light emitted by the phosphor and the LED light that is emitted without contributing to the excitation of the phosphor are mixed and emitted. As a result, the light emitting diode 100 also emits light with a different wavelength from the LED light emitted by the light emitting component 102.

Figure 2 shows the chip type light emitting diode in which the light emitting diode (LED chip) 202 is installed in a recess of a box 204 that is filled with a coating material containing a specified phosphor to form a coating. 201. The light emitting component 202 is fixed using an epoxy resin or the like containing Ag, for example, and an electrode n and an electrode p and the light emitting component 202 are connected to metallic terminals 205 installed on the box 204 by means of wires. drivers 203. In the chip-type light-emitting diode constituted as described above, similarly to the conductive-type light-emitting diode of Figure 1, the fluorescent light emitted by the phosphor and the LED light that is transmitted without being absorbed by the phosphor they are mixed and emitted so that the light emitting diode 200 also emits light with a different wavelength from the LED light emitted by the light emitting component 202.

The phosphor-containing light emitting diode in the manner described above has the following characteristics.

1. The light emitted by the light-emitting component (LED) is normally emitted through an electrode that supplies electrical power to the light-emitting component. The emitted light is partially blocked by the electrode formed on the light emitting component, resulting in a particular emission pattern and therefore not uniformly emitted in every direction. The light emitting diode that contains the fluorescent material, however, can emit light uniformly over a wide range without forming an undesirable emission pattern since the light is emitted after being defined by the fluorescent material.

two. Although the light emitted by the light-emitting component (LED) has a monochromatic peak, the peak is broad and has a high color-giving property. This characteristic results in an indispensable advantage for an application that requires wavelengths of a relatively wide range. The light source for an oaptic imaging scanner, for example, is desirable to have a broad emission peak.

The light emitting diodes of the first and second embodiments to be described below have the configuration shown in Figure 1 or Figure 2, wherein a light emitting component using a semiconductor nitride compound with a relatively high energy in the visible region and a particular phosphor are combined and have such favorable properties as the ability to emit high luminance light and less degradation in efficiency. light emission and less color change after a period of extended use.

In general, a fluorescent material that absorbs light of a short wavelength and emits light of a long wavelength has a higher efficiency than a fluorescent material that absorbs light of a long wavelength and emits light of a short wavelength. , and therefore it is preferable to use a light emitting component of a semiconductor nitride compound which is capable of emitting blue light of a short wavelength. It should be noted that the use of a high luminance light emitting component is considered preferred.

The phosphor to be used in combination with the semiconductor nitride compound light emitting component must meet the following requirements:

1. Excellent resistance against light to withstand high intensity light for an extended period of time, since the fluorescent material is installed in the vicinity of the components

ES 2 148 997 T3 emitters 102, 202 and is exposed to light of as high an intensity as about 30 to 40 times sunlight.

two. Ability to effectively emit light in the blue color region for excitation by means of the light emitting components 102, 202. When using a mixture of colors, it should be capable of emitting blue light, not an ultraviolet ray, with high efficiency .

3. Ability to emit light between green to red regions to mix with blue light to generate white light.

Four. Good temperature characteristics appropriate for its location in the vicinity of the light emitting components 102, 202 and the resulting influence of the temperature difference due to the heat generated by the chip when it is illuminated.

5. Ability to continuously change the color tone in terms of the composition ratio or mixing ratio of a plurality of fluorescent materials.

6. Behavior under climatic conditions for the light emitting diode operating medium.

Form of Realization 1

The light emitting diode of the first embodiment of the present invention employs a semiconductor element with a gallium nitride compound that has a large interband energy gap in the light emitting layer and is capable of emitting blue light and a garnet phosphor activated with cerium, in combination. With such a configuration, the light emitting diode of the first embodiment will be able to emit white light by mixing the blue light emitted by the light emitting components 102, 202 and the yellow light emitted by the blue light excited phosphor.

Since the garnet cerium activated phosphor used in the light emitting diode of the first embodiment, it has high strength and good behavior in climatic conditions, it will be able to emit light with extremely small levels of color change and decrease in luminance of the light. emitted light even when radiated by very intense light emitted by the light emitting components 102, 202 located in the vicinity, for a long period of time.

The components of the light emitting diode of the first embodiment will be described in detail below.

Match

The phosphor used in the light-emitting diode of the first embodiment is a type of phosphor which, when excited by visible light or an ultraviolet ray emitted by the semiconductor light-emitting layer, emits light of a different wavelength from that of the excitement light. Phosphorus is specifically a cerium activated garnet fluorescent material containing at least one element selected from Y, Lu, Sc, La, Gd and Sm and at least one element selected from Al, Ga and In. Following the present invention, the fluorescent material is preferably a yttrium-aluminum-garnet fluorescent material (phosphor YAG) activated with cerium or a fluorescent material represented by the general formula (Re_1-rYe_r)₃(To the_1-a) Ga_to)₅OR₁₂: Ce, where 0 <r <1 and 0 <s <1 and Re is at least one selected from Y and Gd. In the event that the LED light emitted by the light emitting component employs the semiconductor gallium nitride compound and the fluorescent light emitted by the phosphor has a yellow body color is in the relationship of complementary colors, light of white color mixing LED light and fluorescent light.

In the first embodiment, since the phosphor is used mixed with a resin that makes the resin coating 101 and the coating material 201 (detailed below), the color tone of the light emitting diode can be adjusted, including the white color and the color of the incandescent lamp controlling the mixing ratio with the resin or the amount used to fill the cup 105 or the recess of the box 204 will follow the wavelength of the light emitted by the light emitting component gallium nitride.

The distribution of the phosphorous concentration also influences the mixture of colors and their duration. That is, when the phosphor concentration increases from the surface of the liner or mold in which the phosphor is contained towards the light emitting component, it is less likely to be affected by external moisture making it easier to suppress. deterioration

ES 2 148 997 T3 due to humidity. On the other hand, when the phosphorous concentration increases from the light emitting component towards the surface of the mold, it will be more likely to be affected by external moisture, but less likely to be affected by heat and radiation from the component. light emitter, thereby making it possible to suppress the deterioration of the phosphor. Such distributions of phosphorous concentration can be achieved by selecting or controlling the material containing the phosphorus, formation temperature and viscosity, and the configuration and distribution of phosphorus particles.

By using the phosphor of the first embodiment, a light emitting diode with excellent emissivity characteristics can be manufactured since the fluorescent material has sufficient light resistance to provide highly efficient operation, even when close proximity is available. to, or in the vicinity of, the light emitting components 102, 202 with a radiation intensity (Ee) comprised between 3Wcm^-2 and 10 Wcm^-2.

The phosphor used in the first embodiment is, because of its garnet structure, resistant to heat, light and humidity, so it is thus capable of absorbing excitatory light with a peak at a wavelength close to it. at 450 nm, as shown in Figure 3A. It also emits light of a broader spectrum with a peak near 580 nm, fading at 700 nm, as shown in Figure 3B. Furthermore, the efficiency of excited emission of light in the wavelength region 460 nm and above can be increased by including Gd in the phosphor crystal of the first embodiment. When the Gd content is increased, the wavelength of the emissioan peak shifts towards a longer wavelength and the entire emissioan spectrum shifts towards longer wavelengths. This means that, when the emission of light of a more reddish color is required, it can be achieved by increasing the degree of substitution by Gd. When the Gd content is increased, the luminance of the light emitted by photoluminescence under blue light tends to decrease.

Especially, when part of Al is replaced with Ga, between the composition of the fluorescent material YAG by a garnet structure, the wavelength of the emitted light shifts towards a shorter wavelength and, when part of Y is replaced with GD, the wavelength of the emitted light shifts towards a longer wavelength.

Table 1 shows the composition and light-emitting characteristics of the YAG fluorescent material represented by the general formula (Y1-aGda) 3 (Al1-bGab) 5O12: Ce.

<td rowspan="2">n °</td><td rowspan="2">Cont. Gd a (molar rel)</td><td rowspan="2">Cont. Ga b (molar rel)</td><td colspan="2">Chrom coordinates. CIE</td><td rowspan="2">Lum. Y</td><td rowspan="2">Effic.</td>

<td>x</td><td>Y</td>

<td> 1</td><td> 0,0</td><td> 0,0</td><td> 0,41</td><td> 0,56</td><td> 100</td><td> 100</td>

<td> 2</td><td> 0,0</td><td> 0,4</td><td> 0,32</td><td> 0,56</td><td> 61</td><td> 63</td>

<td> 3</td><td> 0,0</td><td> 0,5</td><td> 0,29</td><td> 0,54</td><td> 55</td><td> 67</td>

<td> 4</td><td> 0,2</td><td> 0,0</td><td> 0,45</td><td> 0,53</td><td> 102</td><td> 108</td>

<td> 5</td><td> 0,4</td><td> 0,0</td><td> 0,47</td><td> 0,52</td><td> 102</td><td> 113</td>

<td> 6</td><td> 0,6</td><td> 0,0</td><td> 0,49</td><td> 0,51</td><td> 97</td><td> 113</td>

<td> 7</td><td> 0,8</td><td> 0,0</td><td> 0,50</td><td> 0,50</td><td> 72</td><td> 86</td>

The values ​​shown in Table 1 were measured by exciting the fluorescent material with 460 nm blue light. The luminance and efficiency of Table 1 are given with respect to the relative values ​​of the values ​​of said material number 1 that are established at 100.

When Al is substituted with Ga, the ratio is preferably Ga: Al = 1: 1 to 4: 6 in consideration of the emission efficiency and emission wavelength. Similarly, when

ES 2 148 997 T3 Y is replaced by Gd, the ratio is preferably Y: Gd = 9: 1 to 1: 9 and more preferably 4: 1 to 2: 3. It is because of the degree of substitution with Gd below 20% results in a color with a higher green component and a smaller green component, and a degree of substitution with Gd above 60% results in an increased red component but with a rapid decrease in luminance. When the Y: Gd ratio of Y and Gd in YAG fluorescent material is set between 4: 1 and 2: 3, in particular, a light-emitting diode capable of emitting white light substantially along the radiation site can be fabricated. of the black body using a class of yttrium-aluminum-garnet fluorescent material, as a function of the emission wavelength of the light-emitting component. When the T: Gd ratio of Y and Gd in YAG fluorescent material is set between 2: 3 and 1: 4, a light emitting diode capable of emitting incandescent lamp light could be manufactured even though its luminance is low. When the content (degree of substitution) of EC is set within the ratio of 0.003 to 0.2, a relative luminous intensity of the light emitting diode of not less than 70% could be achieved. When the content is less than 0.003, the light intensity decreases since the number of excited emission centers of photoluminescence due to Ge decreases, and when the content is greater than 0.2, the leachate density occurs.

In this way, the wavelength of the emitted light could be shifted to a shorter wavelength by substituting Ga for the Al part of the composition, and the wavelength of the emitted light could be shifted to a greater wavelength. long replacing part of Y of the composition by Gd. In this way, the color of the emitting light can be changed continuously by changing the composition. Furthermore, the fluorescent material is sparsely excited by the Hg emission lines which have wavelengths of 254 nm and 365 nm, but it is excited more efficiently by the LED light emitted by the blue light emitting component with a length wavelength of approximately 450 nm. In this way, the fluorescent material has ideal characteristics to convert the blue light of the nitride semiconductor light emitting component, into white light, so that the ability to continuously change the peak wavelength by changing the ratio of Gd.

According to the first embodiment, the light emitting efficiency of the light emitting diode could be further improved by combining the light emitting component using a gallium nitride semiconductor and the phosphor manufactured by adding the rare earth element called samarium (Sm) to cerium-activated yttrium-aluminum-garnet (YAG) fluorescent materials.

The material to manufacture said phosphorus is manufactured using oxides of Y, Gd, Ce, Sm, Al and Ga or components that can be easily converted into said oxides at high temperature, and the sufficient mixing of said materials in stoichiometric proportions. Said mixture is mixed with an appropriate amount of a fluoride, such as ammonium fluoride used as flux and heated in an oven at a temperature of 1350 to 1450 ° C in air for 2 to 5 hours. Subsequently, the heated material is ground by ball milling in water, washed, separated, dried and sieved to thereby obtain the desired material.

In the production process described above, the material mixture could also be manufactured by dissolving the rare earth elements Y, Gd, Ce and Sm in stoichiometric proportions in an acid, coprecipitating the solution with oxaolic acid and heating the coprecipitate to obtain an oxide of the material. coprecipitated and subsequently mixing it with aluminum oxide and gallium oxide.

The phosphor represented by the general formula (Y1-pq-rGdpCeqSmr) 3Al5O12 could emit light of wavelengths 460 nm and higher with high efficiency after excitation, since Gd is contained in the crystal. When the gadolinium content is increased, the emission peak wavelength shifts from 530 nm to a longer wavelength to a maximum of 570 nm, while the entire emission spectrum also shifts towards longer wavelengths. . When stronger red shadow light is needed, it can be achieved by increasing the amount of Gd added for replacement. When the Gd content is increased, the blue light photoluminescence luminescence gradually decreases. Thus, the p-value is preferably 0.8 or less, or more preferably 0.7 or less. Maos is preferably 0.6 or less.

The phosphorus represented by the general formula (Y1-pqr GdpCe^what Smr) 3Al5O12 including Sm could be manufactured by subjecting it to less temperature dependence regardless of the increased Gd content. That is, phosphorus, when it contains Sm, has greatly improved emission luminance at high temperatures. The amplitude of the improvement increases as the Ga content increases. The temperature characteristics could be greatly improved by adding Sm in the case of fluorescent material of a composition such that the red shade is reinforced by increasing the Gd content, since it has poor temperature characteristics. The

ES 2 148 997 T3 temperature characteristics mentioned herein are measured in terms of the ratio (%) of the emission luminance of the fluorescent material at high temperature (200 C) in relation to the blue light emission luminance of excitation with a wavelength of 450 nm at normal temperature (25 ° C).

The proportion of Sm is preferably within the limits of 0.0003 &lt;r &lt;0.08 to give a temperature characteristic of 60% or higher. The value of r below said limit leads to a lesser effect of improving the temperature characteristic. When the value of r was above these limits, on the contrary, the temperature characteristic deteriorates. Limits of 0.0007 &lt;r &lt;0.02 for the part of SM where the temperature characteristic becomes 80% or higher is most desirable.

The proportion q of Ce is preferably between the limits 0.0003 &lt;q &lt;0.02, which makes possible a relative emission luminance of 70% or higher. The relative emission luminance refers to the emission luminance in terms of percentage relative to the emission luminance of a fluorescent material where q = 0.03.

When the ratio q of Ce is 0.03 or less, the luminance decreases because of the number of excited emission centers of photoluminescence because Ce decreases, and when q is greater than 0.2, the leachate density occurs. Leachate density refers to the decrease in emission intensity that occurs when the concentration of an activating agent added to increase the luminance of the fluorescent material is increased beyond an optimal level.

A mixture of two or more types of phosphors with light-emitting compositions with different classes of phosphor with compositions of (Y1-pq-rGdpCe^whatSmr) 3Al5O12 and different contents of Al, Ga, Y and Gs orSm also can be used. This increases the RGB components and allows the application of, for example, a full color liquid crystal display device using a color filter.

Light-emitting components 102, 202

The light emitting component is preferably embedded in a molding material as shown in Figure 1 and Figure 2. The light emitting component used in the light emitting diode of the present invention is a gallium nitride compound. semiconductor capable of effectively exciting cerium-activated garnet fluorescent materials. Light emitting components 102, 202 employing a gallium nitride semiconductor compound are manufactured by forming a light emitting layer of semiconductor gallium nitride, such as InGaN, on the substrate in a MOCVD process. The structure of the light emitting component could be a homostructure, ether structure or a double ether structure having a MIS junction, PIN junction or PN junction. Various emission wavelengths could be selected depending on the material of the semiconductor layer and its crystallinity. It could also be manufactured with a single-well quaontic structure or a multi-well quaontic structure in which the semiconductor activating layer is formed as thin as it can produce the quantum effect. According to the present invention, a light-emitting diode capable of emitting with a higher luminance without deterioration of the phosphor could be manufactured by making the activation layer of the light-emitting component according to a single-well InGaN quantic structure.

When using a semiconductor compound of gallium nitride, or of sapphire, spinel, SiC, Si, ZnO, or the like can be used as the semiconductor substrate, the use of sapphire substrate is preferred in order to form gallium nitride of good crystallinity. . A semiconductor gallium nitride layer is formed on the sapphire substrate to form a PN junction by means of a buffer layer of GaN, AlN, etc. The gallium nitride semiconductor has an N-type conductivity under the condition that it is not doped with any impurities, although in order to form an N-type gallium nitride semiconductor with the desired properties (carrier concentration etc.) with an emission of improved light as mentioned, will preferably be doped with an N-type dopant such as Si, Ge, Se, Te, and C. In order to form a P-type gallium nitride semiconductor, on the other hand, it is considered preferred that it should be doped with a P-type dopant, such as Zn, Mg, Be, Ca, Sr, and Ba ,. Since it is difficult to turn a semiconductor gallium nitride compound to P-type simply by doping it with a P-type dopant, it is considered preferable to treat the doped semiconductor gallium nitride compound with a P-type dopant in a process such as heating it in an oven and radiating it with a low speed electron beam and plasma irradiation to thereby return it to the P type. After exposing the surfaces of the P-type and N-type gallium nitride semiconductors by chemical etching or other process, the electrodes with the desired shapes are formed on the semiconductor layers by ion bombardment or vapor deposition.

IS 2 148 997 T3

The formed semiconductor wafer is then cut into pieces by a die saw or separated by external forces after cutting grooves (half cuts) having a width greater than the width of the blade edge. Or else the wafer is cut into chips by etching a grid pattern of extremely fine lones onto the semiconductor wafer by means of an engraver with a diamond punch making a straight reciprocating motion. In such a way, the light emitting component of the gallium nitride semiconductor compound could be manufactured.

In order to emit white light with the light emitting diode of the first embodiment, the wavelength of the light emitted by the light emitting component is preferably 400 nm to 530 nm, inclusive, in consideration of the ratio of complementary color with phosphorus and resin deterioration, and more preferably between 420 nm and 490 nm, inclusive. It is considered more preferred that the wavelength is 450 nm and 475 nm, in order to improve the emission efficiency of the light emitting component and the phosphor. The emission spectrum of the white light emitting diode of the first embodiment is shown in Figure 4. The light emitting component represented in said Figure is of the conductive type shown in Figure 1, which employs the light emitting component and the phosphor of the first embodiment that will be described later. In Figure 4 the emission with a type of approximately 450 nm is the light emitted by the light emitting component and the emission with a type of approximately 570 nm is the photoluminescent emission excited by the light emitting component.

Figure 16 shows the colors that can be represented by the white light emitting diode made by combining the fluorescent material shown in Table 1 and the blue LED (light emitting component) with a peak wavelength of 465 nm. The color of the light emitted by said white light emitting diode corresponds to a point on a straight line that connects a chromaticity point generated by the blue LED and a chromaticity point generated by the fluorescent material, and thus, the Wide white region (shaded part in Figure 16) in the central part of the chromaticity diagram could be completely covered using fluorescent materials 1 to 7 of Table 1. Figure 17 shows the change in the emission color when the content of the fluorescent materials in the white light emitting diode is changed. The content of the fluorescent materials are given in percentages by weight with respect to the resin used in the coating material. As can be seen in Figure 17, the color of the light approaches that of the fluorescent materials when the content of the fluorescent material is increased and approaches that of the blue LED when the content of the fluorescent material is decreased.

According to the present invention, a light emitting component that does not excite the fluorescent material could be used in conjunction with the light emitting component that emits light that excites the fluorescent material. Specifically, in addition to fluorescent material, which is a semiconductor nitride compound capable of exciting fluorescent material, a light-emitting component is jointly composed with a light-emitting layer made of gallium phosphate, aluminum gallium arsenide, arsenium phosphate -galium or aluminum-indium phosphate. With such a configuration, the light emitted by the light emitting component that does not excite the fluorescent material is radiated outwards without being absorbed by the fluorescent material, producing a light emitting diode that can emit red / white light.

Other components of the light emitting diodes in Figure 1 and Figure 2 will be described below.

Lead wires 103, 203

The lead wires 103, 203 shown have good electrical conductivity, good thermal conductivity, and good mechanical connection to the electrodes of the light-emitting components 102, 202. The thermal conductivity is preferably 0.042 J (s) (cm).²) (^◦C / cm) or higher and more preferably 2.09 J (s) (cm²) (^◦C / cm) or higher. To improve working conditions, the diameter of the conductive wire is preferably 10 to 45 µm, inclusive. Even when the same material is used for the coating that includes the fluorescent material and the mold, because of the difference in the coefficient of thermal expansion due to the fluorescent material contained in either of the two materials mentioned above, the conductive wire is quite possible that break on the interface. For this reason, the diameter of the lead wire is preferably not less than 25 µm and, due to the light emitting area and ease of handling, preferably within 35 µm. The conductive wire could be a metal such as gold, copper, platinum and aluminum and an alloy thereof. When a conductive wire of such material and configuration is used, it can be easily connected to the electrodes of the light-emitting components, the internal conductor and the frame conductor by means of a cable or wire joining device.

IS 2 148 997 T3

Conductive mount 105

The conductive mount 105 comprises a cup 105a and a conductor 105b, and its surface is of sufficient size to mount the light emitting component 102 with the wire joining device in the cup 105a. In the case where a plurality of light-emitting components are installed in the cup and a conductive mount is used as the common electrode for the light-emitting component because different electrode materials can be used, sufficient electrical conductivity is required. and good conductivity with the thread of unioán and the others. When the light emitting component is installed in the conductive frame cup and the cup is filled with the fluorescent material, the light emitted by the fluorescent material is, even if isotropic, reflected by the cup in and from a desired direction. In this way, erroneous illumination due to light from other light-emitting diodes mounted nearby can be avoided. By erroneous lighting is meant the phenomenon that other light-emitting diodes mounted in the vicinity appear as illuminators despite not being supplied with power.

The union of the light emitting component 102 and the conductive mount 105 with the cup 105a can be achieved by means of a thermoplastic resin, such as an epoxy resin, an acrylic resin and an imide resin. When the downward facing light emitting component (such as a kind of light emitting component such as emitted light is removed from the substrate side and configured to mount the electrodes opposite the cup 105a) is used, Ag paste may be used, unioan metal carbon paste or the like for electrically bonding and connecting the light emitting component and the conductive mount at the same time. In addition, in order to improve the efficiency of using the light from the light emitting diode, the surface of the conductive mount cup on which the light emitting component is mounted may be specularly polished to provide a reflective function to the light. surface. In this case, a surface roughness of 0.1 S to 0.8 S, inclusive, is preferred (S is a Japanese unit according to ISO 468 of 1982). The electrical resistance of the conductive mount is preferably 300 µΩ-cm and more preferably 3 µΩ-cm. When mounting a plurality of light-emitting components that generate a significant amount of heat and thereby require high thermal conductivity. Specifically, a thermal conductivity of 0.042 J (s) (cm²) (^◦C / cm) or higher and more preferably 2.09 J (s) (cm²) (^◦C / cm) or higher. Materials that satisfy these requirements can contain steel, copper, copper-clad steel, copper-clad tin, and metallized ceramic materials.

Inner conductor 106

The inner conductor 106 is connected to one of the electrodes of the light emitting component 102 mounted on the conductive mount 105 by means of a conductive wire or the like. In the case of a light emitting diode in which a plurality of light emitting components are installed on the conductive mount, it is considered necessary to have a plurality of internal conductors 106 such that the conductive wires do not touch each other. For example, contact of the conductive wires with each other can be avoided by increasing the area of ​​the distal face where the inner conductor is attached to the wire following a distance from the conductive mount that is increased so that the space between the conductive wires is ensured. The surface roughness of the distal face of the inner conductor that connects with the conductor wire is preferably 1.6 S to 10 S, inclusive (S is a Japanese unit according to ISO 468 of 1982) in consideration of close contact.

In order to form the inner conductor to the desired shape, it can be punched by means of a die. Furthermore, it may be manufactured by punching to form an internal conductor subsequently pressurizing it on the distal face to thereby control the area and height of the distal face.

The inner conductor is required to have good conductivity with the bonding wires which are conductive wires and have good electrical conductivity. Specifically, it is preferred that the electrical resistance is 300 µΩ-cm and more preferably 3 µΩ-cm. Materials that meet these requirements contain iron, copper, iron-containing copper, zinc-containing copper, silver-plated aluminum, copper or gold, iron, and copper.

Lining Material 101

The coating material 101 is provided in the conductive mount cup separate from the mold material 104 and, in the first embodiment, contains the phosphor that converts the light emitted by the light emitting component. The lining material may be a transparent material with

ES 2 148 997 T3 good weather behavior, such as an epoxy resin, a urea resin and a silicon or glass resin. A dispersant can be used in conjunction with phosphorus. As a dispersant, it is preferred to use barium titanium, titanium oxide, aluminum oxide, silicon dioxide and the like. When the fluorescent material is formed by sputtering, the coating material may be omitted. In this case, a light emitting diode capable of mixing colors can be manufactured by controlling the thickness of the film or by supplying a film in the layer of fluorescent material.

Material for mold 104

The mold 104 has the function of protecting the light emitting component 102, the conductive wire 103 and the coating material 101 containing phosphorus from external conditions. Following the first embodiment, it is considered preferred that the material for the mold 104 also contains a dispersant, which can deflect the directivity of light from the light emitting component 102, resulting in an increased viewing angle. The material for the mold 104 acts as a lens to focus or diffuse the light emitted by the light emitting component. In addition, the material for the mold 104 may be manufactured in a convex lens or concave lens configuration, and may have an elastic shape when viewed in the direction of the opal axis or a combination thereof. Furthermore, the material for the mold 104 may be manufactured in a multilayer structure of different laminated materials. As the material for the mold 104, transparent materials with good resistance to climatic conditions such as epoxy resin, urea resin, silicon resin or glass can preferably be used. As dispersant, vario titania, titanium oxide, aluminum oxide, silicon dioxide and the like can be used. In addition to the dispersant, the phosphor may be contained in the material for the mold. Namely, according to the present invention, the phosphor may be contained either in the material for the mold or in the coating material. When the phosphor is contained in the mold material, the split angle can be increased further. Phosphorus may also be contained in both the coating material and the material for the mold. In addition, a resin that includes phosphorus with the coating material can be used while glasses are used, different from the coating material, such as the material for the mold. This makes it possible to manufacture a light emitting diode that is less subject to the influence of moisture with good productivity. The mold and the lining may be made of the same material in order to match the refractive index, depending on the application. Following the present invention, the addition of the dispersant and / or a coloring agent in the mold material has the effects of masking the color of the darkened fluorescent material and improving the performance of color mixing. That is, the fluorescent material absorbs the blue component of the extraneous light and emits light to thereby give a truly yellow colored appearance. However, the dispersant contained in the mold material gives a milky white color to the mold material and the coloring agent gives a desired color. In this way, the color of the fluorescent material will not be recognized by the observer. In the case where the light emitting component emits light with a main wavelength of 430 nm or more, it is considered more preferable that an ultraviolet light absorbing element is contained to serve as a light stabilizer.

Different way of realization

The light emitting diode of another embodiment is manufactured using an element provided with a semiconductor gallium nitride compound having an energy gap between bands in the light emitting layer as a light emitting component and a fluorescent material that includes two or more more types of phosphor of different compositions, or preferably yttrium-aluminum-garnet fluorescent materials activated with cerium as phosphor. With this configuration it will be possible to manufacture a light emitting diode that gives a desired color tone by controlling the content of two or more fluorescent materials even when the wavelength of the LED light emitted by the light emitting component deviates from the value. desired due to variations in the production process. In this case, the emissioan color of the light emitting diode can be made constant by using a fluorescent material with a relatively short emission wavelength for a light emitting component of a relatively short emission wavelength and using a fluorescent material. with a relatively long emission length for a light emitting component with a relatively long emission wavelength.

Regarding the fluorescent material, a fluorescent material represented by the general formula (Re1-rSmr) 3 (Al1-aGas) 5O12: Ce could also be used as a phosphor. Here 0 &lt;r &lt;1 and Re is selected from at least between Y, Gd and La. This configuration makes it possible to minimize denaturation of the fluorescent material and even when the fluorescent material is exposed to the high-intensity, high-energy visible light emitted by the light-emitting component for a long period of time or when used under various environmental conditions, said light emitting diode being therefore at a change

ES 2 148 997 T3 of extremely negligible color and low emissioan luminance decay and has the desired high luminance emissioan component.

Phosphor of different embodiment

Next, the phosphor used in the light emitting component of the above-mentioned embodiment will be described in detail. This second embodiment is similar to the first embodiment, with the exception that more types of phosphorus of different compositions activated with cerium are used as the phosphorus, they continue to be described above, the procedure for using the fluorescent material being basically the same.

Similar to the case of the first embodiment, the light-emitting diode can be provided with high stability under weather conditions by controlling the distribution of the phosphor (such as damping the concentration with distance from the emitting component). of light). Such distribution of phosphorous concentration can be achieved by selecting or controlling the material containing the phosphor, the temperature and viscosity of conformation, and the configuration and distribution of the phosphorus particles. In this way, according to said embodiment, the distribution of the concentration of the fluorescent material is determined according to the operating conditions. In addition, according to this embodiment, the efficiency of the light emission can be increased by designating the configuration of the two or more types of fluorescent material (for example, arranging them in the order of proximity to the light emitting component) according to the light generated. by the light emitting component.

With the configuration of said embodiment, similar to the first embodiment, the light emitting diode has high efficiency and sufficient light resistance even when it is arranged close to, or in the vicinity of, the emitting component. light of a relatively high emission with a radiation intensity (Ee) within the limits of 3 to 10 Wcm^-2.

The cerium-activated yttrium-aluminum-garnet fluorescent material (YAG fluorescent material) used in this embodiment has a garnet structure similar to that of the first embodiment, thus being resistant to heat, light and moisture. The excitation peak wavelength of the yttrium-aluminum-garnet fluorescent material of said embodiment can be established in the vicinity of 450 nm as indicated by the solid line in Figure 5A, and the emission type wavelength It may be established in the vicinity of 510 nm, as indicated by the continuous line in Figure 5B, while the emission spectrum is made so broad to cover up to 700 nm, which makes it possible to emit green light. The excitation peak wavelength of another cerium-activated yttrium-aluminum-garnet fluorescent material of said embodiment may be set in the vicinity of 450 nm, as indicated by the dashed line in Figure 5A and the length Emission type waveform may be set in the vicinity of 600 nm as indicated by the dashed line in Figure B while making the emission spectrum so broad as to extend up to 750 nm, which makes it possible to emit red light.

The wavelength of the emitted light is shifted to a shorter wavelength by substituting part of Al, between the constituents of the YAG fluorescent material with a garnet structure, with Ga, and the wavelength of the emitted light. it moves to a shorter wavelength by substituting part of Y with Gd and / or La. The substituent ratio of Al to Ga is preferably Ga: Al = 1: 1 to 4: 6 in consideration of the light emission efficiency and the emission wavelength. Similarly, the ratio of substitution of Y with Gd and / or La is preferably Y: Gd and / or La = 9: 1 to 1: 9 or more preferably Y: Gd and / or La = 4: 1 to 2: 3. Substitution of less than 10% results in an increase in the green component and a decrease in the red component. Substituting 80% or a larger part for the other part increases the red component but abruptly decreases the luminance.

The material for manufacturing said phosphorus is made using Y, Gd, Ce, La, Al, Sm and Ga oxides or components that can be easily converted into said oxides at high temperatures and sufficient mixing of said materials in stoichiometric proportions. Or on the other hand, the material is obtained by dissolving the rare earth elements Y, Gd, Ce, La, Al, Sm in stoichiometric proportions in acid, coprecipitation of the solution with oxalic acid and baking the coprecipitate to obtain an oxide of the coprecipitate, which is subsequently mixed with aluminum oxide and gallium oxide. Said mixture is mixed with an appropriate amount of fluoride, such as ammonium fluoride used as flux and baked in a crucible at a temperature of 1350 to 1450 C in air for 2 to 5 hours. Subsequently, the baked material is ground in a ball mill in water, washed, separated, dried and sieved to obtain the desired material.

IS 2 148 997 T3

In this embodiment, the two or more types of cerium activated yttrium-aluminum-garnet fluorescent material of different compositions can be used for mixing or arranged independently (such as laminates). When the two or more types of fluorescent material are mixed, the color converting part can be formed relatively easily and in a shape suitable for mass production. When the two or more types of fluorescent material are arranged independently, the color could be adjusted after shaping by laminating the layers until a desired color is obtained. Furthermore, when two or more types of fluorescent material are arranged independently, it is considered preferable to have a fluorescent material that absorbs light from the light-emitting component of a short wavelength close to the LED element and a fluorescent material that absorbs light of a length of wave away from the LED element. This configuration enables efficient absorption and emission of light.

The light emitting diode of this embodiment is manufactured using two or more types of yttrium-aluminum-garnet fluorescent materials of different compositions as fluorescent materials, in the manner described above. This makes it possible to manufacture a light emitting diode capable of efficiently emitting light of the desired color. That is, when the wavelength of the light emitted by the semiconductor light-emitting component corresponds to a point on the straight line connecting point A and point B in the chromatic diagram of Figure 6, light of any color in the shaded region enclosed by points A, B, C and D in Figure 6 which are the chromaticity points (points C and D) of the two or more types of yttrium-aluminum-garnet fluorescent materials of compositions different. According to this embodiment, the color could be controlled by changing the compositions or quantities of the LED elements and fluorescent materials. In particular, a light emitting diode of less variation in the emission wavelength could be manufactured by selecting the fluorescent materials according to the emission wavelength of the LED element. In addition, a light emitting diode that includes RGB components with high luminance could be manufactured by selecting the emission wavelength of fluorescent materials.

Furthermore, since the yttrium-aluminum-garnet (YAG) fluorescent material used in this embodiment has a garnet structure, the light emitting diode of this embodiment can emit high luminescence light for a long period of time. . Furthermore, the light emitting diodes of the first embodiment and of the present embodiment are provided with a light emitting component installed via a fluorescent material. Furthermore, because the converted light has a longer wavelength than that of the light emitted by the light emitting component, the energy of the converted light will be less than the energy jump between bands of the nitride semiconductor, for making it less likely to be absorbed by the semiconductor nitride layer. In this way, although the light emitted by the fluorescent material is also directed to the LED element because of the emission isotrope, the light emitted by the fluorescent material is never absorbed by the LED element and thus the emission efficiency and the light emitting diode did not decrease.

Planar light source

A planar light source, which is another embodiment of the present invention, is shown in Figure 7.

In the planar light source shown in Figure 7, the phosphor used in the first embodiment is contained in the coating material 701. With this configuration, the blue light emitted by the semiconductor gallium nitride converts its color and is emitted into a planar state via an optical guide plate 704 and a dispersive sheet 706.

Specifically, a light emitting component 702 of the planar light source of Figure 7 was attached to a metallic substrate 703 with an inverted C shape where an insulating layer and a conductive pattern were formed (not shown). After electrically connecting the electrode of the light-emitting component and the conductive pattern, the phosphor is mixed with an epoxy resin and applied into the inverted C-shaped metal substrate 703 on which the light-emitting component 702 was mounted. The previously secured light emitting component is affixed to a distal face of the acrylic ooptic guide plate 704 by means of an epoxy resin. A reflector film 707 containing a white diffusing agent is disposed on one of the main planes of the ooptic guide plate 704 where the dispersive lamina 706 is not formed, in order to avoid fluorescence.

Similarly, a reflector 705 is disposed over the entire surface of the back of the ooptic guide plate 704 and on a distal face in which the light emitting component is not disposed,

ES 2 148 997 T3 in order to improve the light emission efficiency. With this configuration, light emitting diodes for a planar light emission that generates sufficient luminance for the backlight of the LCE can be manufactured.

The application of the light emitting diode for a planar light emission to a liquid crystal display can be achieved by arranging a polarized plate on a main plane of the 704 optical guide plate guiding the liquid crystal injected between the glass substrates (not shown). on which a translucent conductive pattern is formed.

Referring now to Figure 8 and Figure 9, a planar light source will follow another embodiment of the present invention will be described below. The light emitting device shown in Figure 8 is manufactured with a configuration such that the blue light emitted by the light emitting diode 702 is converted to white light by a color converter 701 that contains phosphor and that is emitted in a planar state. via an oáptic guide plate 704.

The light emitting device shown in Figure 9 is manufactured in a configuration such that the blue light emitted by the light emitting component 702 is returned to a planar state by the optical guide plate 704, being subsequently converted to white light by a dispersive sheet 706 containing phosphor formed on one of the main planes of the anoptic guide plate 704 to thereby emit white light in a planar state. The phosphorus may be either contained in the dispersive sheet 706 or formed in a sheet by dispersing it together with a binding resin on the dispersive sheet 706. In addition, the binding material that includes the phosphorous may be shaped in a specific way, not in sheets. , directly on the Aoptic Guide Plate 704.

App

Display device

A display device following the present invention will be described below. Figure 10 is a block diagram showing the display device configuration according to the present invention. As shown in Figure 10, the display device comprises an LED display device 601 and a driver circuit 610 having a driver 602, a video data storage means 603 and a tone control means 604. The LED display device 601, having white light emitting diodes 501 shown in Figure 1 or Figure 2 arranged in a matrix configuration in a box 504 as shown in Figure 11, is used as the LED display device. monochromatic. The box 504 is provided with a light blocking material 505 integrally formed therewith.

The driver circuit 610 has a video data storage means (RAM) 603 to temporarily store the display data that is input, a tone control means 604 that computes and outputs the tone signals to control the light emitting diodes. individual LED display device to illuminate with specified brightness will follow data read from RAM 603, and a driver 602 that is switched by signals supplied from tone control means 604 to drive the light emitting diode and illuminate. The tone control circuit 604 retrieves the data from the RAM 603 and computes the illumination duration of the light emitting diodes of the LED display device 601, subsequently emitting pulse signals to turn the light emitting diodes of the device on and off. LED screen 601. In the display device constituted as described above, the LED display device 601 is capable of displaying images following the pulse signals input by the driver circuit and has the following advantages.

The LED display device that displays white light using the RGB three-color light-emitting diodes is used to display while controlling the light-emitting output of the R, G and B light-emitting diodes and thereby control the diodes. light emitters taking into account the emission intensity, temperature characteristics and other factors of the light emitting diodes, resulting in a complicated configuration of the driver circuit that drives the LED display device. In the display device of the present invention, however, because the LED display device 601 is constituted by using the light emitting diodes 501 of the present invention which can emit white light without using the light emitting diodes 501. light of three types, RGB, it is not necessary that the driver circuit individually control the light emitting diodes R, G and B, making it possible to simplify the configuration of the driver circuit and the manufacture of the display device at low cost.

With LED display device displaying in white light using three light-emitting diodes

ES 2 148 997 T3 types, RGB, the three light-emitting diodes should be illuminated at the same time and the light from the light-emitting diodes should be mixed in order to display white light by combining the three RGB light-emitting diodes for each pixel, resulting in a large display area for each pixel and making it impossible to display with high definition. The LED display device of the display device according to the present invention, on the contrary, could display with white light and could do so with a single light-emitting diode, thus being capable of displaying with high-definition white light. In addition, with the LED display device that exhibits by mixing the colors of three light-emitting diodes, there is the case of exhibiting color changes due to the blocking of some of the RGB light-emitting diodes depending on the viewing angle but the device of LED display of the present invention does not have such a problem.

As described above, the display device provided with the LED display device employing the light emitting diode of the present invention which is capable of emitting white light is capable of exhibiting stable white light with higher definition and has the advantage of less color unevenness. The LED display device of the present invention which is capable of displaying in white light also imposes less stimulation to the eye compared to a conventional LED display device employing only green and red colors, thus being suitable for long-term use. period of time.

Embodiment of another display device employing the light emitting diode of the present invention

The light emitting diode of the present invention could be used to constitute an LED display device in which a pixel is made up of three RGB light emitting diodes and one light emitting diode of the present invention, in the form shown in Figure 12. By connecting the LED display device and a specified driver circuit, a display device capable of displaying various images could be formed. The driver circuit of said display device has, similarly to the case of a monochrome display device, a video data storage medium (RAM) for temporarily storing the entered display data, a tone control circuit that processes the data stored in RAM to compute the tone signals to illuminate the light emitting diodes with a specified brightness and a driver that can be switched by an output signal from the tone control circuit that cause the light-emitting diodes to illuminate. The driver circuit is exclusively required for each of the RGB light emitting diodes and the white light emitting diode. The tone control circuit computes the illumination duration of the light-emitting diodes from the data stored in RAM and emits pulse signals to turn the light-emitting diodes on and off. When displayed in white light, the width of the pulse signals to illuminate the RGB light-emitting diodes becomes shorter, or the peak value of the pulse signal becomes smaller or no pulse signal is emitted at all. On the other hand, a pulse signal is supplied to the white light emitting diode in compensation for the above, which causes the LED display device to display in white light.

As described above, the display brightness could be improved by adding the white light emitting diode to the RGB light emitting diodes. When RGB light emitting diodes are combined to display white light, one or two of the RGB colors could be enhanced resulting in the impossibility of displaying pure white light depending on the angle of emission, this problem being solved by adding the light emitting diode. white on that display device.

For the drive circuit of a display device as described above, it is considered different that the central processing unit (CPU) is separately provided with the tone control circuit that computes the pulse signal to illuminate the light emitting diode. white with a specified brightness. The pulse signal emitted by the tone control circuit is supplied to the driver of the white light emitting diode to thereby switch the driver. The white light emitting diode illuminates when the driver is on and turns off when the driver is off.

Traffic signals

When the light emitting diode of the present invention is used as a trophic signal, which is a kind of display device, advantages such as stable illumination could be obtained by long period of time without color unevenness even when starting from the light-emitting diodes turns off. The traffic signal using the light emitting diode of the present invention has a configuration such that the white light emitting diodes are arranged on a substrate on which a conductive pattern is formed. A light-emitting diode circuit in which the light-emitting diodes

ES 2 148 997 T3 of light are connected in series or in parallel is manipulated as a set of light emitting diodes. Two or more sets of light emitting diodes are used, each having the light emitting diodes arranged in a spiral configuration. When all the light emitting diodes are arranged, they are arranged over the entire area in a circular configuration. After connecting the power lines by welding for the connection of the light emitting diodes and the substrate with an external power source, it is secured on a chassis of a railway signal. The LED display device is placed in a cast aluminum chassis equipped with a light blocking member and its surface sealed with a silicone rubber filler. The chassis is equipped with a white lens on its display plane. The electrical wiring of the LED display device is passed through the rubber gasket on the rear of the chassis to seal the inside of the chassis from the outside with the bottom of the chassis closed. In this way, a white light signal can be made. A more reliable signal can be made by dividing the light emitting diodes of the present invention into a plurality of groups and arranging them in a spiral configuration that starts from a center towards the outside while they are connected in parallel. The vortex pattern from the center to the outside may be continuous or intermittent. Thus, the desired number of light emitting diodes and the desired number of set of light emitting diodes can be selected based on the display area of ​​the LED display device. This signal is, even when one of the sets of the light-emitting diodes or part of the light-emitting diodes do not illuminate due to some problem capable of illuminating evenly in a circular configuration without color shift by means of the remaining set of diodes light-emitting diodes or other light-emitting diodes. Because the light emitting diodes are arranged in a spiral configuration, they can be arranged more densely near the center and excited without any different impression from the signals used by incandescent lamps.

Examples

The following examples illustrate the present invention in detail, but are not intended to limit the scope thereof.

Example 1

Example 1 provides a light emitting component having an emission peak at 450 nm and a half bandwidth of 30 nm using a GaInN semiconductor. The light emitting component of the present invention is being manufactured with TMG (trimethyl) flowing gas. gallium), TMI gas (trimethyl indium), Nitrogen gas and a dopant gas together with a carrier gas on a clean sapphire substrate and forming a semiconductor layer of a gallium nitride compound in the MOCVD process. A gallium nitride semiconductor with an N-type conductivity and a gallium nitride semiconductor with a P-type conductivity are formed by switching SiH4 and Cp2Mg (bi (cyclopentadienyl) magnesium) as the dopant gas. The LED element in Example 1 has a contact layer that is a gallium nitride semiconductor with an N-type conductivity and a buffer layer that is a gallium-aluminum nitride semiconductor with a P-type conductivity and a contact layer that is a gallium nitride semiconductor having a P-type conductivity and is formed between the contact layer having an N-type conductivity and the buffer layer having a P-type conductivity as a layer of INGAN undoped activation approximately 3 nm thick to fabricate a single-well quantum structure. The well substrate has a gallium nitride semiconductor layer formed thereon under a low temperature to make a buffer layer. The P-type semiconductor is fired at a temperature of 400^°C or higher after forming the film.

After exposing the surfaces of the P-type and N-type semiconductor layers by chemical etching, N and P electrodes are formed by ion bombardment. After writing the semiconductor wafer which has been manufactured as described above, the light emitting components are manufactured by dividing the wafer with an external force.

The light emitting component manufactured in the above process is mounted in a cup of a conductive mount that is made of silver-plated steel for die bonding with an epoxy resin. Next the electrodes of the light emitting component, the conductive frame and the inner conductor are electrically connected by conductive wires with 30 µm diameter gold wire to make a conductive type light emitting diode.

Phosphorus is manufactured by dissolving the rare earth elements Y, Gd, and Ce in an acid in stoichiometric proportions and coprecipitating the solution with oxaalic acid. The oxide of the coprecipitate obtained by baking said material is mixed with aluminum oxide to thereby obtain the mixed material.

IS 2 148 997 T3

The mixture is subsequently mixed with ammonium fluoride used as flux and baked in a crucible at a temperature of 1,400 C in air for 3 hours. Next, the cooked material is ground in a ball mill in water, washed, separated, dried and sieved to thereby obtain the desired material. The phosphor manufactured in the manner described above is a yttrium-aluminum-garnet fluorescent material represented by the general formula (Y0.8Gd0.2) 3Al5O12: Ce in which approximately 20% of Y is substituted by Gd at a substitution ratio of Ce of 0.03.

parts by weight of the fluorescent material with a composition of (Y0.8Gd0.2) 3Al5O12: Ce which has been manufactured with the above-mentioned process and 100 parts by weight of epoxy resin are mixed sufficiently to make them a solution. The solution is poured into the cup arranged in the conductive mount on which the light emitting component is mounted. After pouring, the solution is cured at 130 ° C for one hour. In this way a coating having a thickness of 120 µm containing the phosphor is formed on the light emitting component. In Example 1 the coating is formed to contain the phosphor in a gradually increasing concentration towards the light emitting component. The intensity of irradiation is approximately 3.5W / cm2. The light emitting component and the phosphor are molded with translucent epoxy resin to protect against external stresses, humidity and dust. A conductive frame with a phosphor coating layer formed thereon is placed in a bullet-shaped mold and mixed with the translucent epoxy resin and cured at 150 ° C for 5 hours.

Upon visual observation of the light emitting diode formed as described above in the direction normal to the light emitting plane, it was found that the central part gave a yellowish color due to the color of the phosphor body.

The measurements of the chromaticity point, color, temperature and color contribution index of the light emitting diode manufactured as described above and capable of emitting white light gave values ​​of (0.302, 0.280) for the chromaticity point (x, y ), a color temperature of 880 K and 87.5 for the color production index (Ra) which are approximate to the characteristics of a waveform 3 fluorescent lamp. The light emission efficiency was 9.5 lm / W, comparable to that of the incandescent lamp. In addition, in useful life tests under energizing conditions with a current of 60 mA at 25 ° C, 20 mA at 25 ° C and 20 mA at 60 ° C, with 90% relative humidity, no change was observed due to the fluorescent material. , proving that the light emitting diode had no difference in its useful life compared to a conventional blue light emitting diode.

Comparative Example 1

The formation of the light emitting diode and the useful life tests were conducted in the same way as in example 1 except for the change of the phosphor (Y0.8Gd0.2) 3Al5O12: Ce to (ZnCd) S: Cu, Al. The light emitting diode formed will show, immediately after its energization, the emission of white light but with low luminance. In a useful life test the emission will decrease to zero in approximately 10 hours. Analysis of the cause of the deterioration showed that the fluorescent material had turned black.

This problem is supposed to be caused by the light emitted by the light-emitting component and the moisture that had plugged the fluorescent material or entered from the outside carried by photoolysis to produce colloidal zinc and precipitate on the surface of the fluorescent material, resulting in a blackened surface. The results of the useful life test under energizing conditions with a current of 20 mA at 25^°Cy20mAa60^°C, with 90% relative humidity are shown in Figure 13 together with the results of example 1. The luminance is given in terms of relative value with respect to the initial value for reference. A solid line indicates Example 1 and a wavy line indicates Comparative Example 1 in Figure 13.

Example 2

In Example 2, a light-emitting component was manufactured in the same way as in Example 1 except that the In content in the semiconductor nitride compound of the light-emitting component was increased so that it would have an emissioan peak at 460 nm and the Gd content will be increased in the phosphorus than in example 1 to have a composition (Y0.6Gd0.4) 3Al5O12: Ce.

The measurements of the chromaticity point, color temperature and color contribution index of the light emitting diode were made in the manner described above and capable of emitting white light, gave values ​​of (0.375, 0.370) for the chromaticity point ( x, y), color temperature of 4400 K and color contribution index (Ra) of 86.0. Figures 18A, 18B and 18C show the emission spectrum of phosphorus, the

ES 2 148 997 T3 light emitting component and the light emitting diode of Example 2, respectively.

100 pieces of light emitting diodes from Example 2 were manufactured and their average luminous intensities were taken from them after illumination of 1000 hours. In terms of percentage of the luminous intensity value before the useful life test, the average luminous intensity after the useful life test was 98.8%, proving that there were no differences in these characteristics.

Example 3

100 Light-emitting diodes were made in the same way as in Example 1, except that Sm was added in addition to the rare earth elements Y, Gd, and Ce to the phosphor to make a fluorescent material with a composition of (Y0.39Gd0, 57Ce0.03Sm0.01) 3Al5O12. When the light emitting diodes were made to illuminate at a high temperature of 1.30 C, the average temperature characteristic was about 8% better than that of Example 1.

Example 4

An example 4 LED display device was manufactured with the light emitting diodes of example 1 arranged in a 16 by 16 matrix on a cerome material substrate on which a copper pattern was formed as shown in Figure 11. In the LED display device of Example 4, the substrate on which the light emitting diodes were arranged is located in a chassis 504 made of phenol resin and provided with a light blocking member 505 integrally formed therewith. The chassis, the light-emitting diodes, the substrate, and part of the light-blocking member, except for the tips of the light-emitting diodes, were covered with 502 silicon rubber colored black with a pigment. The substrate and light emitting diodes were welded by means of an automated welding machine.

The LED display device manufactured by the configuration described above, a RAM that temporarily stores the entered display data, a tone control circuit that processes the data stored in RAM to compute the tone signals to illuminate the light-emitting diodes with a specified brightness and a driving medium that is switched by the output signal of the tone control circuit to make the illuminated light-emitting diodes electrically connected to make an LED display device. By driving the LED display device it was verified that the apparatus can be used as a black and white LED display device.

Example 5

The light emitting diode of Example 5 was manufactured in the same manner as in Example 1 with the exception that phosphor represented by the general formula (Y0.2Gd0.8) 3Al5O12: Ce was used. 100 pieces of light emitting diodes from Example 5 were manufactured and various of their characteristics were measured.

The chromaticity point measurements gave average values ​​of (0.450, 0.420) for the chromaticity point (x, y) and light was emitted from a colored incandescent lamp. Figure 19A, Figure 19B and Figure 19C show the emission spectrum of the phosphor, the light emitting component and the light emitting diode of Example 5, respectively. Although the light-emitting diodes of Example 5 showed a luminance of approximately 40% lower than that of the light-emitting diodes of Example 5, they showed a good climatic performance characteristic comparable to those of Example 1 in the useful life test.

Example 6

The light emitting diode of Example 6 was manufactured in the same way as in Example 1 with the exception that phosphor represented by the general formula Y3Al5O12: Ce was used. 100 pieces of light emitting diodes from Example 6 were manufactured and various of their characteristics were measured.

Measurements of the chromaticity point of slightly greenish-yellow white light compared to Example 1 was emitted. The light emitting diode of Example 6 showed a good performance characteristic under climatic conditions similar to those of Example 1 in the useful life test. Figures 20A, 20B and 20C show the emission spectrum of the phosphor, the light emitting component and the light emitting diode of Example 6, respectively.

IS 2 148 997 T3

Example 7

The light emitting diode of Example 7 was manufactured in the same way as in Example 1 with the exception that phosphor represented by the general formula Y3 (Al0.5Ga0.5) 5O12: Ce was used. 100 pieces of light emitting diodes from Example 7 were manufactured and various of their characteristics were measured.

Although the light emitting diodes of Example 7 exhibited low luminance, they emitted greenish-white light and exhibited good performance characteristics under similar climatic conditions to those of Example 1 in the useful life test. Figures 21A, 21B and 21C show the emission spectrum of the phosphor, the light emitting component and the light emitting diode of Example 7, respectively. Example 8

The light emitting diode of Example 8 was manufactured in the same way as in Example 1 with the exception that phosphorus represented by the general formula Gd3 (Al0.5Ga0.5) 5O12: Ce was used. 100 pieces of light emitting diodes from Example 8 were manufactured and various of their characteristics were measured.

Although the light emitting diodes of Example 8 showed low luminance, they showed good performance under climatic conditions similar to that of Example 1 in the useful life test.

Example 9

The light emitting diode of Example 9 is a planar light emitting device with the configuration shown in Figure 7.

An In0.05Ga0.95N semiconductor with an emission peak at 450 nm was used as the light emitting component. The light emitting components were manufactured by flowing TMG gas (trimethyl gallium), TMI gas (trimethyl indium), nitrogen gas and dopant gas together with a carrier gas over a clean sapphire substrate forming a semiconductor layer of a gallium nitride compound. in a MOCVD process. A gallium nitride semiconductor layer with N-type conductivity and a gallium nitride semiconductor layer with P-type conductivity were formed by switching SiH4 and Cp2Mg (bis (cyclopentadienyl) magnesium as dopant gas, thereby forming a PN junction. For the semiconductor light emitting component, a contact layer of a gallium nitride semiconductor with an N-type conductivity, a gallium nitride-aluminum semiconductor coating layer with an N-type conductivity, a gallium nitride coating layer -Semiconductor aluminum with a P-type conductivity and a gallium nitride semiconductor contact layer with a P-type conductivity were formed. A Zn-doped InGaN activating layer that makes a double bond was formed between the coating layer with an N-type conductivity and a coating layer with a P-type conductivity. A buffer layer was provided on the sapphire substrate forming a layer. gallium nitride semiconductor at low temperature. The P-type nitride semiconductor layer was fired at a temperature of 400 ^ or higher after film formation.

After forming the semiconductor layers and exposing the surfaces of the P-type and N-type semiconductor layers by chemical etching, electrodes were formed by electron bombardment. After etching the semiconductor wafer manufactured as described above the light emitting components were made light emitting components by splitting the wafer with an external force.

The light-emitting component was mounted on a conductive mount having a cup at the tip of a silver-plated copper conductive frame, die-bonded with epoxy resin. The electrodes of the light-emitting component, the conductive frame, and the inner conductor were electrically connected by wire bonding with 30 µm diameter gold wires.

The conductive frame with the light-emitting component fixed thereon was placed in a bullet-shaped die and sealed with a translucent epoxy resin for molding, which was subsequently cured at 150 ° C for 5 hours to thereby form a blue light emitting diode. The blue light emitting diode was connected to a distal face of the acrylic optic guide plate and its distal faces were polished. Screenprints were applied to a surface and a distal face of the acrylic plate using vario titania dispersed in an acrylic binder as a reflector of the white color which was subsequently cured.

Green and red colored phosphorus was manufactured by dissolving the rare earth element of Y, Gd, Ce and La, in acid in stoichiometric proportions and the solution was co-precipitated with oxoalic acid. Coprecipitate oxide was obtained by baking said material mixed with aluminum oxide and gallium oxide to obtain

ES 2 148 997 T3 thus the materials of the respective mixture. The mixture was subsequently mixed with ammonium fluoride used as flux and baked in a crucible at a temperature of 1,400 C in air for three hours. The cooked material is then ground in a ball mill in water, washed, separated, dried and sieved to obtain the desired material.

120 parts by weight of the first fluorescent material with a composition of Y3 (Al0.6Ga0.4) 5O12: Ce and capable of emitting green light will be prepared in the manner described above and 100 parts by weight of a second fluorescent material with a composition of ( Y0.4Gd0.6) 3Al5O12: Ce and capable of emitting red light was prepared in a process similar to that of the first fluorescent material, being sufficiently mixed with 100 parts by weight of epoxy resin to form a solution. The solution will be applied uniformly on the acrylic layer with a thickness of 0.5 mm by means of a multicoat and dried to form a layer of fluorescent material to be used as a color-converting material with a thickness of approximately 30 µm. The layer of fluorescent material is cut to the same size as the main light-emitting plane of the optical guide plate and disposed on the oaptic guide plate to thereby form the planar light emitting device. The measurements of the chromaticity point and the color supply index of the light emitting device gave values ​​of (0.29, 0.34) for the chromaticity point (x, y) and 92.0 for the supply index of color (Ra) which are approximately the properties of a 3 waveform fluorescent lamp. The light emitting efficiency of 12 lm / W was comparable to that of the incandescent lamp. Furthermore, in performance tests under climatic and energizing conditions with a current of 60 mA at laboratory temperature, 20 mA at laboratory temperature and 20 mA at 60 C with 90% relative humidity, no changes were observed in the fluorescent material.

Comparative Example 2

The conformation of the light-emitting diode and the performance tests under climatic conditions were conducted in the same way as in Example 9 except for mixing the same quantities of a green organic fluorescent pigment (FA-001 from Synleuch Chemisch). and a red organic fluorescent pigment (FA-005 from Synleuch Chemisch) which are derived from perylene, instead of the first fluorescent material represented by the general formula of Y3 (Al0.6Ga0.4) 5O12: Ce capable of emitting green light and the second fluorescent material represented by the general formula of (Y0.4Gd0.6) 3Al5O12: Ce capable to emit red light from Example 9. The chromaticity coordinates of the light emitting diode from Comparative Example 1 thus formed were (x, y) = (0.34, 0.35). The performance characteristics under climatic conditions were measured in a test carried out by radiation with ultraviolet rays generated by a carbonaceous arc for 200 hours, representing an equivalent radiation of sunlight during a period of one year while the retention ratio of luminance and color tone several times during the test period. In a reliability test, the light-emitting component is energized to emit light at a constant temperature of 70 ° C while measuring luminance and color tone at different times. The results are shown in Figure 14 and Figure 15 in conjunction with Example 9. As clearly seen in Figures 14 and 15, the light-emitting component of Example 9 experiences less decay than Comparative Example 2.

Example 10

The light emitting diode of Example 10 is a conductive type light emitting diode.

In the light-emitting diode of Example 10, a light-emitting component with a light-emitting layer of In0.05Ga0.95N with an emissioan peak at 450nm manufactured in the same way as Example 9 was used. The light was mounted in the cup provided at the tip of a conductive silver-plated copper mount, by means of a die with epoxy resin. The electrodes of the light emitting component, the conductive frame and the inner conductor were electrically connected by gold wire union.

The phosphor will be manufactured by mixing a first fluorescent material represented by the general formula Y3 (Al0.5Ga0.5) 5O12: Ce capable of emitting green light and a second fluorescent material represented by the general formula (Y0.2Gd0.8) 3Al5O12: Ce capable of emitting red light and will be prepared as follows. Namely, the rare earth elements Y, Gd and Ce were dissolved in acid in stoichiometric proportions and the solution was co-precipitated with oxalic acid. The oxide of the coprecipitation obtained by heating was mixed with aluminum oxide and gallium oxide to thereby obtain the respective mixing materials. The mixture was mixed with ammonium fluoride used as flux and baked in a crucible at a temperature of 1,400 ^ C in air for 3 hours. Next, the baked material was ground in a ball mill with water, washed, separated, dried and sieved to obtain the fluorescent materials first.

ES 2 148 997 T3 and second with the specified particle distribution.

parts by weight of the first fluorescent material, 40 parts by weight of the second fluorescent material and 100 parts by weight of epoxy resin were sufficiently mixed to form a suspension. The suspension will be poured into the cup provided over the conductive mount in which the light emitting component is placed. Then the resin including phosphorus will cure to 130^°C for one hour. In this way, a coating layer including the phosphor with a thickness of 120 µm is formed on the light emitting component. The concentration of the phosphor in the coating layer will gradually increase towards the light emitting component. In addition, the light emitting component and the phosphor were sealed by molding with a translucent epoxy resin to protect against external stresses, humidity and dust. A conductive frame with the phosphor coating layer formed thereon was placed in a bullet-shaped die and mixed with the translucent epoxy resin and subsequently cured at 150^°C for 5 hours. Upon visual observation of the light emitting diode formed in the manner described above in the direction normal to the light emitting plane it was found that the central part provided yellowish color due to the color of the phosphor body.

Measurements of the chromatic point, color, temperature and color contribution index of the light emitting diode of Example 10 manufactured in the manner described above gave values ​​of (0.32, 0.34) for the chromaticity point (x , y), 89.0 for the color contribution index (Ra) and a light emission efficiency of 10 lm / W. In addition, in performance tests under climatic conditions and energization with a current of 60 mA at room temperature, 20 mA at room temperature and 20 mA at 60^°C, with 90% relative humidity, no changes were observed due to the phosphor, showing no differences with an ordinary blue light emitting diode in the useful life characteristics.

Example 11

An In0.4Ga0.6N semiconductor with an emission peak of 470 nm will be used as the LED element. The light emitting components were manufactured by flowing TMG (trimethyl gallium) GTMI (trimethyl indium) gas, nitrogen gas, and dopant gas together with a carrier gas over a clean sapphire substrate to thereby form a semiconductor layer of a nitride compound. gallium in the MOCVD process. A gallium nitride semiconductor layer with N-type conductivity and a gallium nitride semiconductor layer with P conductivity were formed by switching SiH4 and Cp2Mg (bis (cyclopentadiethyl) magnesium) used as dopant gas, to thereby form a union. PN. For the LED element, a gallium nitride semiconductor contact layer with an N-type conductance, a coating layer with a gallium-aluminum nitride semiconductor with a P-type conductivity, and a gallium nitride semiconductor contact layer with a P-type conductivity were formed. An undoped InGaN activation layer approximately 3 nm thick is formed between the contact layer with an N-type conductivity and a coating layer with a P-type conductivity to thereby fabricate a single-well quantum structure. A buffer layer will be delivered on the sapphire substrate by forming a low temperature gallium nitride semiconductor layer.

After forming the layers and exposing the surfaces of the P-type and N-type semiconductor layers by chemical attack, the electrodes were formed by ion bombardment. After drawing the semiconductor wafer manufactured as described above, the light emitting components of the wafer were cut with an external force.

The light-emitting component was mounted in a cup at the tip of a conductive silver-plated copper mount by die-bonding with epoxy resin. The electrodes of the first light-emitting component, the conductive frame and the inner frame are electrically connected by joint with gold wires with a diameter of 30 µm.

The conductive frame with the light emitting component fixed on it will be placed in a bullet-shaped die and sealed with a translucent epoxy resin for molding, which will subsequently be cured at 150^° for 5 hours, to thereby form a blue light emitting diode. The blue light emitting diode was connected to a distal face of the acrylic oaptic guide plate polishing its distal faces. On a surface and a lateral face of the acrylic plate a screen printing was applied using barium itamate dispersed in an acrylic binder as a white reflector which was subsequently cured.

The phosphor will be manufactured by mixing a fluorescent material represented by the general formula (Y0.8Gd0.2) 3Al5O12: Ce capable of emitting yellow light of a relatively short wavelength and a

ES 2 148 997 T3 fluorescent material represented by the general formula (Y0.4Gd0.6) 3Al5O12: Ce capable of emitting yellow light of a relatively long wavelength prepared with the threads. The rare earth elements Y, Gd and Ce were dissolved in acids in stoichiometric proportions and the solution was co-precipitated with oxaalic acid. The oxide of the coprecipitation obtained by heating will be mixed with aluminum oxide to thereby obtain the mixing material. The mixture was subsequently mixed with ammonium fluoride used as flux and fired in a crucible at a temperature of 1,400^°C in air for 3 hours. The cooked material was then ground with a ball mill in water, washed, separated, dried and sieved.

100 parts by weight of the relatively short wavelength yellow fluorescent material and 100 parts by weight of a relatively long wavelength yellow fluorescent material manufactured as mentioned above were sufficiently mixed with 1000 parts by weight of acrylic resin and It will be extruded to thereby form a film of the fluorescent material for use as a color converting material approximately 180 µm thick. The film of fluorescent material was cut to the same size as the main emission plane of the oaptic guide plate and disposed on the oaptic guide plate to thereby fabricate a light emitting device. Measurements of the chromaticity point and color contribution index of the light emitting device of Example 3 manufactured as described above gave values ​​of (0.33, 0.34) for the chromaticity point (x, y) for the color delivery index (Ra) and a light emission efficiency of 101 m / W. Figures 22A, 22B and 22C show the emission spectra of the fluorescent material represented by (Y0.8Gd0.2) 3Al5O12: Ce and a fluorescent material represented by the general formula (Y0.4Gd0.6) 3Al5O12: Ce used in the example. 11. Figure 23 shows the emissioan spectrum of the light emitting diode of example 11. After some useful life tests under energizing conditions with a current of 60 mA at room temperature, 20 mA at room temperature and 20 mA at 60^°C, with 90% relative humidity, no changes were observed in the fluorescent material. Similarly, the desired chromaticity can be maintained even when the wavelength of the light emitting component is changed when the content of the fluorescent material is changed.

Example 12

The light emitting diode of Example 12 was manufactured in the same way as in Example 1 except that phosphor represented by the general formula Y3In5O12: Ce will be used. 100 pieces of the light emitting diode from Example 12 were manufactured. Although the light emitting diode of example 12 showed a lower luminance than that of the light emitting diodes of example 1, it showed good performance characteristics in climatic conditions comparable to those of example 1 in the useful life test.

In the way described above, the light emitting diode of the present invention will be able to emit light of a desired color and its emission efficiency will be subject to less deterioration, with good performance characteristics in climatic conditions even when used with high luminance during a long period of time. In this way, the application of the light-emitting diode is not limited to electronic devices but can open new applications including screens for automobiles, airplanes and buoys for ports, as well as outdoor use as signals and lighting for communication routes.