BRPI9715364B1 - LIGHT EMISSION DEVICE, BACKGROUND LIGHT SOURCE AND LIQUID CRYSTAL DISPLAY - Google Patents

Abstract

light emitting device, backlight source and liquid crystal display. The present invention relates to a white light-emitting diode comprising a light-emitting component (102) using a semiconductor as a light-emitting layer and a phosphorescent substance (101) which absorbs a portion of the light emitted by the light. light-emitting component (102) and emits light of a different wavelength than that of absorbed light, where the light-emitting layer of the light-emitting component is a nitride compound semiconductor and the phosphorescent substance (101) contains a cerium activated grenade fluorescent material which contains at least one element selected from the group consisting of y, lu, sc, la, gd and sm, and at least one element selected from the group consisting of al, ga and ln, and is subject to less emission characteristic deterioration even when used at high luminance for a long period of time.

Description

Report of the Invention Patent for "LIGHT EMISSION, BACKGROUND SOURCE AND LIQUID CRYSTAL DISPLAY".

Divided from PI 9710792-1, filed July 29, 1997, BACKGROUND OF THE INVENTION (Field of the Invention) The present invention relates to a light-emitting diode used in an LED display, a power source. backlight, a traffic signal, a railroad signal, a light switch, an indicator, etc. More particularly, it relates to a light emitting device (LED) comprising a fluorescent material which converts the wavelength of light emitted by a light emitting component and emitting light, and a display device using the light emitting device, (Related Art Description) [003] An LED is compact and emits light colored light with high efficiency. It is also free from a problem such as burning and has good initial drive characteristics, high vibration resistance and durability to withstand repeated on / off operations because of its semiconductor element. Thus, it has been widely used in applications such as varied indicators and varied light sources. Recently, RBG (red, green and blue) color light-emitting diodes having ultra-high luminance and high efficiency have been developed, and large-screen LED displays using these light-emitting diodes have been put to use. The LED display can be operated with less power and has good features such as light weight and long service life and is therefore expected to be more widely used in the future.

Recently, several attempts have been made to make white light sources using light emitting diodes. Because the LED has a favorable emission spectrum to generate monochromatic light, making a light source for white light requires having three light emitting components of R, G and B next to each other while diffusing and mixing. the light emitted by them. When generating white light with such an arrangement, it has been a problem that white light of the desired tone cannot be generated due to variations in tone, 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 the drive differs from one light emitting diode to the other, making it necessary to apply different voltages to the light emitting components, which leads to a complex drive circuit. Furthermore, because light emitting components are semiconductor light emitting components, color tone is subject to variation due to differences in temperature characteristics, chronological changes and operating environment, or a non-uniformity of color may be caused due to a failure to uniformly blend the light emitted by the light-emitting components. Thus, light-emitting diodes are effective as light-emitting devices for individual color generation, although a satisfactory light source capable of emitting white light by the use of light-emitting components has not been obtained so far.

In order to solve these problems, the present applicant has previously developed light emitting diodes which convert the color of light which is emitted by the light emitting components by means of a fluorescent material shown in Japanese Patent Kokai No. 5-152609, 7-99345, 7-176794, and 8-8614. The light-emitting diodes shown in these publications are such that, by using light-emitting components of one type, they are capable of generating light of white and other colors, and are constituted as follows.

The light-emitting diode shown in the above publications are made by mounting a light-emitting component, which has a high-energy light-emitting layer emission spectrum, in a housing provided at the tip of a light-emitting frame. having a fluorescent material that absorbs the light emitted by the light-emitting component and emits light of a different wavelength than that of the absorbed light (wavelength conversion) contained in a resin mold that covers the light-emitting component. light emission.

The LED shown as described above capable of emitting white light by mixing light from a plurality of sources can be made using a light emitting component capable of emitting blue light and shaping the light emitting component. light with a resin that includes a fluorescent material that absorbs light emitted by the blue LED and emits yellowish light.

However, conventional light-emitting diodes have problems such as deterioration of the fluorescent material leading to a color tone deviation and dimming of the fluorescent material, resulting in decreased light extraction efficiency. Dimming here refers to the use of an inorganic fluorescent material, such as a (Cd, Zn) S fluorescent material, for example, that part of the metal elements constituting the fluorescent material precipitate or change their properties. which lead to staining or, if an organic fluorescent material is used, staining due to the double bond breakage in the molecule. Especially when a light emission component made of a semiconductor having a high energy emission spectrum is used to improve the conversion efficiency of the fluorescent material (ie the light energy emitted by the semiconductor is increased and the number of photons having energies above a threshold that can be absorbed by the fluorescent material increases, resulting in more light being absorbed), or the amount of fluorescent material consumption is decreased (ie the fluorescent material is irradiated with an actively higher king energy), The light energy absorbed by the fluorescent material inevitably increases, resulting in more significant degradation of the fluorescent material. Use of the light emitting component with higher intensity of light emitting for an extended period of time causes even more significant degradation of the fluorescent material.

Also, fluorescent material provided in the vicinity of a light-emitting component may be exposed to a high temperature, such as the high temperature of the light-emitting component and the heat transmitted from the external environment (eg light from the light). sun if the device is used outdoors).

Also, 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 is an ionic property organic dye, the direct current electric field in the vicinity of the chip can cause electrophoresis, resulting in a change in color tone. SUMMARY OF THE INVENTION

Thus, 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 degrees of deterioration in light emission intensity, light efficacy and color deviation over a long period. Use time with high luminance.

The present inventor has completed the present invention through research based on the assumption that a light emitting device having a light emitting component and a fluorescent material must meet the following requirements to obtain the above mentioned object. (1) The light-emitting component shall be capable of emitting high-luminance light with a light-emitting characteristic that is stable for a long time in use. (2) The fluorescent material being provided in the vicinity of the high luminance light-emitting component shall exhibit excellent light and heat resistance, so that its properties do not change even when used for an extended period of time while being exposed. to a high intensity light emitted by the light-emitting component (particularly, the fluorescent material provided in the vicinity of the light-emitting component is exposed to light of a radiation intensity as high as about 30 to 40 times that of light). estimated, and is required to have more durability against light as the high luminance light emitting component is used). (3) With respect to the relationship with the light-emitting component, the fluorescent material shall be capable of absorbing with high efficiency the high monochromaticity light emitted by the light-emitting component and emitting light of a wavelength other than that of light. emitted by the light-emitting component.

Thus, the present invention provides a light-emitting device comprising a light-emitting component and a fluorescent material capable of absorbing a portion of the light emitted by the light-emitting component and emitting light of wavelength. different from that of absorbed light; wherein said light-emitting component comprises a nitride compound semiconductor represented by the formula: lnjGajAlkN (where 0 <i, 0 <j, 0 <kei + j + k = 1) and said fluorescent material contains a fluorescent material grenade comprising at least one element selected from the group consisting of Y, Lu, Sc, La, Gd and Sm, and at least one element selected from the group consisting of Al, Ga and In, and being activated with cerium.

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

The fluorescent material mentioned above contains various materials defined as described above, including Y3AI5O1: Ce and Gd3ln50i2: Ce.

Due to the fact that the light emitting device of the present invention uses the light emitting component made of a nitride compound semiconductor capable of emitting light with high luminance, the light emitting device is capable of emitting light with High luminance. Also, the fluorescent material used in the light emitting device has excellent light resistance, so that its fluorescent properties experience less change even when used for an extended period of time while being exposed to high intensity light. This makes it possible to reduce feature degradation over a long period of use and to reduce deterioration due to the high intensity light emitted by the light emitting component as well as external light (sunlight including ultraviolet light, etc.) during a outdoor use, thereby providing a light emitting device that experiences extremely minor color deviation and less luminance decrease. The light emitting device of the present invention may also be used in applications requiring response speeds as high as 120 nsec., For example, because the fluorescent material used herein permits residual luminescence for only a short period of time.

The fluorescent material used in the light emitting diode of the present invention preferably contains a yttrium aluminum garnet fluorescent material containing Y and Al which allows to increase the luminance of the light emitting device.

In the light-emitting device of the present invention, the fluorescent material may be a fluorescent material represented by a general formula (Rei.rSmr) 3 (AI1.sGas) 50i2: Ce, where 0 <r <1 and 0 < s <1 and Re is at least one selected from Y and Gd, in which case good characteristics can be obtained similarly to the case where yttrium - aluminum - garnet fluorescent material is used.

Also in the light-emitting device of the present invention, it is preferable in order to reduce the temperature dependence of light-emitting characteristics (emitted wavelength, light-emitting intensity, etc.), use a fluorescent material represented by a general formula (Yi-Pq rGdpCeqSmr) 3 (AI1.sGas) 50i2 as the fluorescent material, where 0 <p <0.8, 0.003 <q <0.2, 0.0003 <r < 0.08 and 0 <s <1.

Also in the light-emitting device of the present invention, the fluorescent material may comprise two or more cerium-activated yttrium-garnet fluorescent materials of different compositions including Y and Al. The desired color may be emitted by controlling the emission spectrum of the fluorescent material according to the property (emitted light wavelength) of the light emitting component.

Still in the light-emitting device of the present invention, in order to have a specific wavelength light emitted by the light-emitting device, it is preferable that the fluorescent material contains two or more fluorescent materials of different compositions represented. by the general formula (King. rSmr) 3 (AI1.sGas) 50i2: Ce, where 0 <r <1 and 0 <s <1 eRe is at least one selected from Y and Gd.

Also in the light emitting device of the present invention, in order to control the emitted wavelength of light, the fluorescent material may contain a first fluorescent material represented by the general formula YsiAI ^ Gas ^ O ^ Ce and a second material fluorescent is represented by the general formula Re3AI5Oi2: Ce where 0 <s <1 and Re is at least one selected from Y, Gd and La.

Also in the light-emitting device of the present invention, in order to control the emitted light wavelength, the fluorescent material may be a yttrium-aluminum-garnet fluorescent material containing a first fluorescent material and a second fluorescent material , with different parts of each yttrium being replaced by gadolinium.

Still in the light-emitting device of the present invention, it is preferable that the main emission peak of the light-emitting component be set in the range between 400 nm and 530 nm, and the main emission wavelength of the fluorescent material. be set to be longer than the main emission peak of the light-emitting component. This makes it possible to efficiently emit white light.

Still in the light-emitting device of the present invention, it is preferable that the light-emitting layer of the light-emitting component contains a gallium nitride semiconductor which contains In, and the fluorescent material is a fluorescent material. yttrium - aluminum - garnet, where a part of Al is replaced by Ga, so that the ratio of Ga: AI is in the range 1: 1 to 4: 6 and a part of Y is replaced by Gd, so that Y: Gd ratio is in the range of 4: 1 to 2: 3. The absorption spectrum of the fluorescent material, which is controlled as described above, shows good agreement with that of light emitted by the light-emitting component, which contains the gallium nitride semiconductor, including In as the light-emitting layer. , and is capable of improving the conversion efficiency (luminous efficacy of light). Also, the light generated by the mixture of blue light emitted by the light-emitting component and fluorescent light of the fluorescent material is a white light of good color interpretation and, in this sense, an excellent light-emitting device can be provided.

The light emitting device according to an embodiment of the present invention comprises a substantially rectangular optical guide plate provided with the light emitting component mounted on a side face thereof via the fluorescent material and whose surfaces thereof except by a main surface are substantially covered with a reflective material, where light emitted by the light-emitting component is transformed into flat light by the fluorescent material and the optical guide plate to be extracted from the main surface of the optical guide plate.

The light emitting device according to another embodiment of the present invention has a substantially rectangular optical guide plate which is provided with the light emitting component mounted on one side thereof and the fluorescent material installed thereon. on a main surface with the surfaces thereof and except for the main surface to be substantially covered with a reflective material, where the light emitted by the light emitting component is transformed into flat light by the optical guide plate and the fluorescent material to be an exit from the main surface of the optical guide plate.

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 drive circuit which drives the LED display device. LED according to a display data, which is entered into it. This configuration makes it possible to provide a relatively low priced LED display device which is capable of high definition display with less color non-uniformity due to the viewing angle.

The LED according to an embodiment of the present invention comprises: a mounting wire having a housing and a wire; an LED chip mounted on the mounting wire housing with one of the electrodes being electrically connected to the mounting wire; a transparent coating material filling the housing to cover the LED chip; and a light emitting diode having a molding material which covers the LED chip covered by the sheath material including the mounting wire housing, the inner wire and another LED chip electrode, where the LED chip is a nitride compound semiconductor and the coating material contains at least one element selected from the group consisting of Y, Lu, Sc, La, Gd and Sm, at least one element selected from the group consisting of Al, Ga and In, and a fluorescent material made from cerium activated grenade fluorescent material.

The fluorescent material used in the LED of the present invention preferably contains a yttrium-aluminum-garnet fluorescent material containing Y and Al.

In the LEDs of the present invention, the fluorescent material may be a fluorescent material represented by a general formula (Rei.rSmr) 3 (AI1.sGas) 5012: Ce, where 0 <r <1e0 <s <1e Re is at least one selected from Y and Gd.

Also in the LEDs of the present invention, the fluorescent material represented by a general formula (Yi-pq. RGdpCeqSmr) 3 (Ali.sGas) 5012 may be used as the fluorescent material, where 0 <p <0, 8, 0.003 <q <0.2, 0.0003 <r <0.08 and 0 <s <1.

In the LEDs of the present invention, the fluorescent material preferably contains two or more cerium-activated yttrium-garnet fluorescent materials of different compositions including Y and Al in order to control the light emitted for a desired wavelength.

In the LED of the present invention, similarly, two or more fluorescent materials of different compositions represented by a general formula (Rei-rSmr ^ Ali. SGas) 50i2: Ce, where 0 <r <1 and 0 <s <1 and Re is at least one selected from Y and Gd may be used as the fluorescent material to control the light emitted to a desired wavelength.

In the LED of the present invention, similarly, a first fluorescent material represented by a general formula Y3 (AI1.sGas) 5Oi2: Ce and a second fluorescent material represented by a general formula Re3AI50i2: Ce may be used. as the fluorescent material, where 0 <s <1 and Re is at least one selected from Y, Ga and La, to control the light emitted to a desired wavelength.

In the LED of the present invention, similarly, a yttrium - aluminum - garnet fluorescent material, a first fluorescent material and a second fluorescent material may be used, where the part of yttrium in the first and second fluorescent materials It is replaced with gadolinium in varying degrees of substitution as the fluorescent material in order to control the light emitted to a desired wavelength.

Generally, a fluorescent material which 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. It is preferable to use a light-emitting component which emits visible light than a light-emitting component that emits resin-degrading ultraviolet light (molding material, coating material, etc.). Thus, for the LEDs of the present invention, for the purpose of improving the light efficiency of light and ensuring a long service life, it is preferable that the main emission peak of the light-emitting component be set to a wavelength range. relatively short wavelength from 400 nm to 530 nm in the visible light region, and the main emission wavelength of the fluorescent material is set to be longer than the main emission peak of the light emission component. With this arrangement, because light converted by fluorescent material has a longer wavelength than 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 forbidden band energy). Thus, light that has been reflected by fluorescent or similar material is reflected by the enclosure where the light-emitting component is mounted, making higher luminous efficacy possible.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 is a schematic cross-sectional view of a conductor type LED according to the embodiment of the present invention.

Figure 2 is a schematic cross-sectional view of a tip-type LED according to the embodiment of the present invention.

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

Figure 3B is a graph showing the emission spectrum of the cerium activated grenade fluorescent material used in the first embodiment of the present invention.

Figure 4 is a graph showing the LED emission spectrum of the first embodiment of the present invention.

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

Figure 5B is a graph showing the emission spectrum of the cerium-activated yttrium-aluminum garnet fluorescent material used in the second embodiment of the present invention.

Figure 6 shows the LED light chromaticity diagram of the second embodiment, while points A and B indicate the light colors emitted by the light emitting component and points C and D indicate the colors of light emitted by both types of phosphorescent substances.

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

Figure 8 is a schematic cross-sectional view of another flat light source other than that of Figure 7.

Figure 9 is a schematic cross-sectional view of another flat light source other than those of Figure 7 and Figure 8.

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

[0051] Figure 11 is a plan view of the LED display of the display device of Figure 10.

[0052] Figure 12 is a plan view of the LED display device where a pixel is made up of four light-emitting diodes, including the LEDs of the present invention and those emitting RGB colors.

Figure 13A shows the results of the durable life test of the LEDs of Example 1 and Comparative Example 1, showing the results at 25 °, and Figure 13B shows the results of the durable life test of the LEDs. Example 1 and Comparative Example 1, showing the results at 60 ° and 90% RH (Relative Humidity).

Figure 14A shows the results of the climate test of Example 9 and Comparative Example 2, which shows the change in luminance retention relationship with time, and Figure 14B shows the results of Example 9 and Comparative Example. 2 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 the luminance retention ratio and time, and Figure 15B is a graph showing the relationship between color tone. And the time.

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

Figure 17 is a chromaticity diagram showing the change in color tone when the concentration of fluorescent material is changed on the LED that combines the fluorescent materials shown in Table 1 and the blue LED having a length of peak wave at 465 nm.

Figure 18A shows the emission spectrum of the fluorescent material (Y 0.6 Gdo, 4) 3 Al 15 O 12: Ce from Example 18A.

Figure 18B shows the emission spectrum of the light emission component of Example 18B having the peak emission wavelength of 460 nm.

Figure 18C shows the emission spectrum of the LED of Example 2.

Figure 19A shows the emission spectrum of the fluorescent material (Yo ^ Gdo.s ^ AlsO- ^ Ce of Example 5).

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

[0063] Figure 19C shows the emission spectrum of the LED of Example 5.

Figure 20A shows the emission spectrum of fluorescent material Y3AI50i2: Ce of Example 6.

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

Figure 20C shows the LED emission spectrum of Example 6.

Figure 21A shows the emission spectrum of fluorescent material Y3 (Al105Ga0.5) 50O2: C e of the seventh embodiment of the present invention.

Figure 21B shows the emission spectrum of the light emission component of Example 7 having the emission peak wavelength of 450 nm.

Figure 21C shows the emission spectrum of the LED of Example 7.

Figure 22A shows the emission spectrum of the fluorescent material (YaeGdo ^ bAIsG ^ Ce of Example 11).

Figure 22B shows the emission spectrum of the fluorescent material (Example 11).

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

Figure 23 shows the emission spectrum of the LEDs of Example 11.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to the accompanying figures, preferred embodiments of the present invention will be described below.

An LED 100 of Figure 1 is a conductor type LED having a mounting wire 105 and an inner wire 106, where a light-emitting component 102 is installed in a housing 105a of the mounting wire 105, and housing 105a is filled with a coating resin 101 which contains a specific fluorescent material to cover light-emitting component 102 and is molded into the resin. An electrode n and a p electrode of the light-emitting component 102 are connected to the mounting wire 105 and the inner wire 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 (from this point referred to as LED light) excites the fluorescent material contained in the coating resin 101. to generate fluorescent light having a different wavelength than LED light, such that the fluorescent light emitted by the fluorescent material and the LED light which is extracted without contributing to the excitation of the fluorescent material are mixed and extracted. As a result, LED 100 also extracts light having a different wavelength than LED light emitted by light emitting component 102.

Figure 2 shows a chip-type LED, where the LED (LED chip) 202 is installed in a recess of a housing 204, which is filled with a coating material which contains a specific fluorescent material to form a coating 201. The light-emitting component 202 is fixed using an epoxy resin or the like, which contains Ag, for example, and an electrode n and a p-electrode of the light-emitting component. 202 are connected to metal terminals 205 installed in the housing 204 by conductor wires 203. In the chip-type LEDs constituted as described above, similar to the conductor-type LEDs of Figure 1, the light The fluorescent light emitted by the fluorescent material and the LED light, which is transmitted without being absorbed by the fluorescent material, are mixed and extracted, so that the LED 200 also extracts light having a wavelength other than that of the LED light emitted by the light-emitting component 202.

The LED containing the fluorescent material as described above has the following characteristics. 1. Light emitted by a light-emitting component (LED) is usually emitted through an electrode, which supplies electrical energy to the light-emitting component. The emitted light is partially blocked by the electrode formed in the light-emitting component resulting in a particular emission pattern, and therefore is not uniformly emitted in all directions. The LED, which contains the fluorescent material, however, can emit light uniformly over a wide range without forming an undesirable emission pattern, because light is emitted after being diffused by the fluorescent material. 2. Although light emitted by the light-emitting component (LED) has a monochrome peak, the peak is large and has a high color interpretation property. This feature is an indispensable advantage for an application that requires relatively wide range wavelengths. It is desirable for a light source for an optical image scanner, for example, to have a broader 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, which uses a nitride compound semiconductor having relatively high energy. high in the visible region, and a particular fluorescent material are combined, and have favorable properties, such as the ability to emit high luminance light and less light efficiency degradation and less color deviation over an extended period of use.

In general, a fluorescent material which 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 long wavelength and emits light of a short wavelength, and therefore it is preferable to use a nitride compound semiconductor light-emitting component which is capable of emitting short wavelength blue light. Needless to say, the use of a light emission component that has high luminance is preferable.

[0081] A fluorescent material to be used in combination with the nitride compound semiconductor light-emitting component shall have the following requirements: 1. Excellent light resistance to allow high intensity light for a long period of time , because the fluorescent material is installed in the vicinity of the light emitting components 102, 202 and is exposed to light as high as about 30 to 40 times that of sunlight. 2. Ability to emit light efficiently in the blue region for excitation through light-emitting components 102, 202. When a color mix is used, it must be capable of emitting blue light, not an ultraviolet ray, with a high efficiency. . 3. Ability to emit light from green to red regions for blending with blue light to generate white light. 4. Good temperature characteristic suitable for a location in the vicinity of the light emitting components 102, 202 and the resulting influence of temperature difference due to the heat generated by the chip when igniting. 5. Ability to continuously change color tone in terms of composition ratio or mixing ratio with a plurality of fluorescent materials. 6. Climatization capability for LED operating environment.

Embodiment 1 The LED of the first embodiment of the present invention employs a semiconductor element of gallium nitride compound which has a high energy emission spectrum in the light emission layer and is capable of emitting blue light. , and a cerium-activated fluorescent garnet fluorescent material in combination. With this configuration, the LED of the first embodiment can emit white light by mixing the blue light emitted by the light emitting components 102, 202 and the yellow light emitted by the fluorescent material excited by the blue light. [0083] Due to the material Cerium-activated grenade fluorescent lamp, which is used in the LED of the first embodiment, has a light and climate resistance, it can emit light with extremely small degrees of color deviation and decreased luminance of the emitted light, even when irradiated by a very bright light emitted by the light emitting components 102, 202 located in the vicinity for a long period of time.

The LED components of the first embodiment will be described in detail below. (Fluorescent Material ^ [0085] The fluorescent material used in the LED of the first embodiment is a fluorescent material which, when excited by visible light or an ultraviolet ray emitted by the semiconductor light-emitting layer, emits light of a wavelength. The fluorescent material is specifically a cerium-activated grenade fluorescent material which contains at least one element selected from Y, Lu, Sc, Gd and Sm, and at least one element selected from Al, Ga In accordance with the present invention, the fluorescent material is preferably a cerium-activated yttrium-aluminum fluorescent material (YAG fluorescent material), or a fluorescent material represented by the general formula (Rei-rSmr) 3 (Ali where 0 <r <1 and 0 <s <1 eRe is at least one selected from Y and Gd. In the case of the LED light emitted by the light-emitting component employing the semicolon. gallium nitride compound inducer and the fluorescent light emitted by the fluorescent material having a yellow body color being in the complementary color ratio, the white color can be extracted by mixing the LED light and the fluorescent light.

In the first embodiment, because the fluorescent material is used by mixing with a resin which forms coating resin 101 and coating material 201 (detailed later), the color tone of the LED may be be adjusted, including white and incandescent lamp color, by controlling the mixing ratio with the resin or the amount used to fill the housing 105 or the recess of housing 204 according to the wavelength of light emitted by the light emission of gallium nitride.

The concentration distribution of fluorescent material also influences mixing and color durability. That is, when the concentration of fluorescent material increases from the surface of the coating or molding where the fluorescent material is contained toward the light-emitting component, it is less likely to be affected by external moisture, thereby making it easier to suppress deterioration. due to moisture. On the other hand, when the concentration of fluorescent material increases from the light-emitting component toward the molding surface, it is more likely to be affected by external humidity, but less likely to be affected by heat and radiation from the emission component. light, thereby making it possible to suppress the deterioration of the fluorescent material. These fluorescent material concentration distributions can be obtained by selecting or controlling the material containing the fluorescent material, forming the temperature and viscosity, and the particle size configuration and distribution of the fluorescent material.

By using the fluorescent material of the first embodiment, an LED can be made having excellent emission characteristics, because the fluorescent material has enough light resistance for high efficiency operation even when arranged adjacent to or in the vicinity. of light emitting components 102, 202 with radiation intensity (Ee) in the range 3 Wcm'2 to 10 Wcm'2.

The fluorescent material used in the first embodiment, because of the grenade structure, is heat, light and moisture resistant, and therefore is capable of absorbing excitation light having a peak at a wavelength close to 450 nm, as shown in figure 3A. It also emits broad spectrum light having a peak near 580 nm, ending at 700 nm, as shown in figure 3B. Further, the luminous efficacy of light excited at a region of 460 nm and higher wavelengths can be increased by including Gd in the crystal of the fluorescent material of the first embodiment. When the Gd content is increased, the emission peak wavelength is shifted toward a longer wavelength and the entire emission spectrum is shifted toward longer wavelengths. This means that when redder light emission is required, it can be obtained by increasing the degree of substitution with Gd. When the Gd content is increased, the luminance of light emitted by photoluminescence under blue light tends to decrease.

Especially when part of Al is replaced with a Ga within the composition of YAG fluorescent material having a grenade structure, the emitted wavelength of light shifts toward a shorter wavelength, and when Y is replaced by Gd, the wavelength of the emitted light shifts toward a longer wavelength.

Table 1 shows the composition and light emission characteristics of the fluorescent YAG material represented by the general formula (Y1, aGda) 3 (AI1bGab) 5012: Ce.

Table 1 The values shown in Table 1 were measured by excitation of the 460 nm blue light fluorescent material. The luminance and efficiency in Table 1 are given in values relative to those of material No. 1, which are set to 100.

When replacing Al by Ga, the ratio is preferably in the range of Ga: AI = 1: 1 to 4: 6, in consideration of light efficiency and emission wavelength. Similarly, when substituting Y for Gd, the ratio is preferably in the range of Y: Gd = 9: 1 to 1: 9, and more preferably from 4: 1 to 2: 3. This is because a Gd substitution degree below 20% results in a higher component green color and a lower red component color, and a Gd substitution degree above 60% results in an increased red component component, but a rapid decrease in luminance. When the Y: Gd ratio of Y and Gd in YAG fluorescent material is regulated in the range of 4: 1 to 2: 3, in particular, an LED capable of emitting white light substantially equivalent to blackbody radiation. can be made using a type of yttrium - aluminum - garnet fluorescent material, depending on the emission wavelength of the light emitting component. When the Y: Gd ratio of Y and Gd in YAG fluorescent material is dimmed in the range 2: 3 to 1: 4, an LED capable of emitting incandescent lamp light can be made although luminance is low. When the Ce content (degree of substitution) is set within the range 0.003 to 0.2, the relative light intensity of the LED of no less than 70% may be obtained. When the content is less than 0.003, the light intensity decreases because of the number of excited photoluminescence emission centers due to Ce decreasing, and when the content is greater than 0.2, density damping occurs.

Thus, the wavelength of the emitted light can be shifted to a shorter wavelength by replacing part of the composition's Al with Ga, and the wavelength of the emitted light can be shifted to a shorter wavelength. long by replacing part of Y of the composition with Gd. In this way, the light emission color can be changed continuously by changing the composition. Also, fluorescent material is heavily excited by Hg emission lines, which have wavelengths such as 254 nm and 365 nm, but is excited with higher efficiency by LED light emitted by a blue light emitting component. having a wavelength around 450 nm. Thus, the fluorescent material has ideal characteristics for converting blue light from the nitride semiconductor light-emitting component to white light, such as the ability to continuously change the peak wavelength by changing the Gd ratio.

According to the first embodiment, the light efficiency of the LED can be further enhanced by combining the light-emitting component employing the gallium nitride semiconductor and the fluorescent material made by the addition of a light element. samarium rare earth (Sm) to cerium activated yttrium aluminum garnet (YAG) fluorescent materials.

The material for making a fluorescent material is made by using oxides of Y, Gd, Ce, Sm, Al and Ga or compounds which can easily be converted to such oxides at high temperature, and by sufficiently mixing such materials. in stoichiometric proportions. This mixture is mixed with an appropriate amount of a fluoride, such as ammonium fluoride used as a flux, and burned in a crucible at a temperature of 1350 to 1450Ό in the air for 2 to 5 hours. Then the burnt material is milled in a ball mill in water, washed, separated, dried and sieved to thereby obtain the desired material.

In producing the process described above, the mixing material may also be made by dissolving the rare earth elements Y, Gd, Ce and Sm in stoichiometric proportions in an acid, co-precipitating the solution into oxalic acid and burning. the co-precipitate to obtain a co-precipitated oxide, and then mixing it with aluminum oxide and gallium oxide.

The fluorescent material represented by the general formula (Y-i. P.q.rGdpCeqSmr) 3 Al 5 O 12 can emit light of 460 nm and longer wavelengths with higher efficiency upon excitation, because Gd is contained in the crystal. When gadolinium content is increased, the emission peak wavelength shifts from 530 nm to a longer wavelength of up to 570 nm, while the entire emission spectrum also shifts to longer wavelengths. . When a stronger red light is needed, it can be obtained by increasing the amount of Gd added for replacement. When the Gd content is increased, the photoluminescence luminance with blue light gradually decreases. Therefore, the value of p is preferably 0.8 or less, and more preferably 0.7 or less. Most preferably, it is 0.6 or less.

The fluorescent material represented by the general formula (Yi_p_q_rGdpCeqSmr) 3 Al 5 O 12 including Sm may be made less subject to temperature dependence regardless of the increased Gd content. That is, the fluorescent material, when containing Sm, has a greatly improved emission luminance at higher temperatures. The extent of the enhancement increases as the Gd content is increased. The temperature characteristic can be greatly improved particularly by adding Sm in the case of a fluorescent material of such a composition as the red tone is increased by increasing the Gd content because it has poor temperature characteristics. The temperature characteristic mentioned here is measured in terms of the emission luminance ratio (%) of the fluorescent material at a high temperature (200Ό) relative to the excitation blue light emission luminance having a wavelength of 450 nm at the temperature. normal (25Ό).

The Sm ratio is preferably in the range of 0.0003 <r <0.08 to provide a temperature characteristic of 60% or higher. The value of r below this range leads to a minor effect of improving the temperature characteristic. When the value of r is above this range, by contrast, the temperature characteristic deteriorates. The range of 0.0007 <r <0.02 for the Sm ratio where the temperature characteristic becomes 80% or higher is most desirable.

The q ratio of Ce is preferably in the range of 0.003 <q <0.2, which makes possible a relative emission luminance of 70% or higher. Relative emission luminance refers to the emission luminance in terms of the percentage of the emission luminance of a fluorescent material where q = 0.03.

When the q ratio of Ce is 0.003 or less, the luminance decreases because the number of excited photoluminescence emission centers due to Ce decreases and when q is greater than 0.2, density damping occurs. Density damping refers to the decrease in emission intensity, which occurs when the concentration of an activating agent added to increase the luminance of the fluorescent material is increased beyond an optimum level.

For the light emitting diode of the present invention, a mixture of two or more types of phosphorescent substances having compositions of (Yi-pq-, GdpCeqSmr) 3 Al5012 having different Al, Ga, Y and Gs or Sm contents also can be used. This enhances the RGB components and allows application, for example, to a full color liquid crystal display device using a color filter. (Light Emitting Components 102, 202) The light emitting component is preferably housed in a molding material as shown in Figure 1 and Figure 2. The light emitting component used in the light emitting diode Light of the present invention is a gallium nitride compound semiconductor capable of efficiently exciting cerium activated grenade fluorescent materials. Light emitting components 102, 202 employing a gallium nitride compound semiconductor are made by forming a gallium nitride semiconductor light emitting layer such as InGaN or a substrate in the MOCVD process. The light-emitting component structure can be a homostructure, a heterostructure, or a double heterostructure, which have an MIS junction, a PIN junction, or a PN junction. Various emission wavelengths may be selected depending on the material of the semiconductor layer and its crystallinity. It can also be made into a single quantum well structure or a multiple quantum well structure, where a semiconductor activation layer is formed as thin as possible for the quantum effect to occur. In accordance with the present invention, an LED capable of emitting with high luminance without deterioration of the fluorescent material can be made by fabricating the activation layer of the light-emitting component into a single InGaN quantum well structure.

When a gallium nitride compound semiconductor is used, while sapphire, spinel, SiC, Si, ZnO or the like may be used as the semiconductor substrate, the use of sapphire substrate is preferable to form a gallium of good crystallinity. A semiconductor layer of gallium nitride is formed on the sapphire substrate to form a PN junction via a temporary storage layer of GaN, AIN, etc. The gallium nitride semiconductor has an N-type conductivity under the condition that it is undoped with any impurity, although to form an N-type gallium nitride semiconductor having the desired properties (carrier concentration, etc.), such as improved light efficiency, it is preferably coated with an N-type coating such as Si, Ge, Se, Te, and C. In order to form a P-type gallium nitride semiconductor, on the other hand, it is preferably coated with a type P coating such as Zn, Mg, Be, Ca, Sr and Ba. Because it is difficult to transform a P-type gallium nitride compound semiconductor by simply coating it with a P-type coating, it is preferable to treat the P-coated gallium nitride compound semiconductor into a P-type coating. process such as furnace heating, low-speed electron beam irradiation, and plasma irradiation to thereby transform it into P-type. After exposure of the surfaces of P-type gallium nitride semiconductors and Type N by chemical etching or other processes, the electrodes of the desired shapes are formed in the semiconductor layers by sputtering or vapor deposition.

Then the semiconductor wafer, which has been formed, is cut into pieces by means of a tableting saw, or separated by an external force after cutting cavities (half-cut), which have wider width than that the width of the blade edge. Or, otherwise, the chip is cut into chips by streaking a grid pattern of extremely thin lines on the semiconductor chip by means of a chip that has a diamond stylus that makes a reciprocal straight motion. Thus, the semiconductor light emission component of gallium nitride compound can be made.

In order to emit white light with the light emitting diode of the first embodiment, the wavelength of light emitted by the light emitting component is preferably from 400 nm to 530 nm inclusive, considering the complementary color ratio with fluorescent material and resin deterioration, and more preferably from 420 nm to 490 nm inclusive. It is even more preferable for the wavelength to be from 450 nm to 475 nm in order to improve the light efficiency of the light emitting component and fluorescent material. The emission spectrum of the white light emitting diode of the first embodiment is shown in Figure 4. The light emitting component shown here is of the conductor type shown in Figure 1, which employs the light emitting component and the fluorescent material. of the first embodiment to be described later. In Figure 4, emission having a peak around 450 nm is the light emitted by the light-emitting component, and emission having a peak around 570 nm is the photoluminescent emission excited by the light-emitting component.

Figure 16 shows the colors that can be represented by the white LED made by the combination of the fluorescent material shown in Table 1 and the blue LED (light emitting component) having a peak wavelength of 465 nm. . The light color emitted by this white light emitting diode corresponds to a point in 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 portion in figure 16) in the central portion of the chromaticity diagram can be completely covered by using the fluorescent materials 1 to 7 in Table 1. Figure 17 shows the emission color change when the fluorescent material contents in the LED White light are changed. Fluorescent material contents are given as a percentage by weight of the resin used in the coating material. As will be seen from Figure 17, the light color approaches that of the fluorescent materials when the fluorescent material content is increased and approaches that of the blue LED when the fluorescent material content is decreased.

In accordance with the present invention, a light-emitting component which does not excite the fluorescent material may be used in conjunction with the light-emitting component which emits light that excites the fluorescent material. Specifically, in addition to fluorescent material which is a nitride compound semiconductor capable of exciting fluorescent material, a light-emitting component that has a light-emitting layer made of gallium phosphate, gallium aluminum arsenide, Arsenic and gallium, or aluminum and indium phosphate, are disposed together. With this configuration, light emitted by the light-emitting component, which does not excite the fluorescent material, is radiated outside without being absorbed by the fluorescent material, constituting a light-emitting diode that can emit red / white light.

Other components of the light emitting diodes of Figure 1 and Figure 2 will be described below. (Lead wires 103. 203) [00111] Lead wires 103, 203 should have good electrical conductivity, good thermal conductivity, and good mechanical connection to the light emitting component electrodes 102, 202. Thermal conductivity is preferably 0, 01 cal / s (cm 2) (O / cm) or higher, and more preferably 0.5 cal / s (cm 2) ('C / cm) or higher. For workability, the diameter of the lead wire is preferably from 10 pm to 45 pm inclusive. Even when the same material is used for coating including fluorescent material and molding due to the difference in thermal expansion coefficient due to the fluorescent material contained in one of the two materials above, the conductive foil tends to break at the interface. For this reason, the diameter of the lead wire is preferably not less than 25pm and, depending on the light emitting area and ease of handling, preferably up to 35 pm. The lead wire can be metal such as gold, copper, platinum, aluminum or any alloy thereof. When a lead wire of such a material and configuration is used, it can be easily connected to the electrodes of the light-emitting components. , to the inner wire and to the mounting wire through a wire connector. (Mounting wire 105) Mounting wire 105 comprises a housing 105a and a wire 105b, and is sufficiently large for mounting the light-emitting component 102 to the wire connector in the housing 105a. Where a plurality of light emitting components are installed in the enclosure and the mounting wire is used as a common electrode for the light emitting component, because different electrode materials may be used, a conductivity is required. sufficient electrical power and good conductivity with the connecting wire and others. When the light-emitting component is installed in the mounting wire housing and the housing is filled with the fluorescent material, the light emitted by the fluorescent material is, even if isotropic, reflected by the housing in a desired direction and therefore may Avoid wrong lighting due to light from another LED mounted nearby. Wrong lighting here refers to a phenomenon such as another nearby mounted LED appearing illuminated even though it is not being supplied with power.

The connection of the light-emitting component 102 and the mounting wire 105 with the housing 105a may be achieved by a thermoplastic resin such as an epoxy resin, an acrylic resin and an imide resin. When a downward facing light-emitting component (such as a type of light-emitting component as the emitted light is extracted from the side of the substrate and is configured to mount the electrodes to oppose the housing 105a) is used, a paste Ag, a carbon paste, a metal mass or the like can be used for the wiring and electrical connection of the light-emitting component and the mounting wire at the same time, in order to improve light utilization efficiency. From the LED, the surface of the mounting wire housing where the light-emitting component is mounted can be polished and mirrored to provide a reflection function to the surface. In this case, the surface roughness is preferably from 0.1 S to 0.8 S inclusive. The electrical resistance of the mounting wire is preferably 300 μΩ - cm and more preferably 3 μΩ - cm. When mounting a plurality of light-emitting components to the assembly wire, the light-emitting components generate a significant amount of heat and therefore high thermal conductivity is required. Specifically, the thermal conductivity is preferably 0.01 cal / s (cm2) (CC / cm) or higher, and more preferably 0.5 cal / s (cm2) (CC / cm2). cm) or higher. Materials that meet these requirements include steel, copper, copper-coated steel, copper-coated tin, and metallized ceramics. (Inner wire 106) [00114] Inner wire 106 is connected to one of the light-emitting component 102 electrodes mounted. to the mounting wire 105 by means of a conductive wire or the like. In the case of a light emitting diode where a plurality of light-emitting components are installed on the mounting wire, a plurality of internal wires 106 must be arranged so that the conductor wires do not touch each other. For example, the lead wire count can be prevented by increasing the area of the end face where the inner wire is wired as the distance from the mounting wire increases, so that the gap between the lead wires be safe, The surface roughness of the inner wire end face is preferably from 1.6 S to 10 S, including close contact consideration.

In order to form the inner cable in a desired shape, it can be stamped by means of a die. Further, it may be stamped to form the inner cable when pressurizing it to the end face to thereby control the area and height of the end face.

[00116] The inner wire is required to have good connection ability with the connecting wires, which are conductive wires and have good electrical conductivity. Specifically, the electrical resistance is preferably 300 pO.cm and more preferably 3 μΩ.αη. Materials that meet these requirements contain iron, copper, iron-containing copper, tin-containing copper, aluminum, iron and copper coated with copper, gold or silver. (Coating Material 101) Coating material 101 is provided in the separate assembly wire wrap of the impression material 104 and in the first embodiment contains the fluorescent material that converts the light emitted by the light-emitting component. The coating material may be a transparent material that has good climate, such as epoxy resin, urea and silicone resins or glass. A dispersant may be used together with the fluorescent material. As a dispersant, barium titanate, titanium oxide, aluminum oxide, silicon dioxide and the like are preferably used. When fluorescent material is formed by cathodic deposition, the coating material may be omitted. In this case, a color-changing LED can be made by controlling the thickness of the film or providing an opening in the fluorescent layer. (Impression material 104) Impression 104 has the function of protecting the light-emitting component 102, the conductor wire 103 and the coating material 101 which contains the fluorescent material from external disturbance. According to the first embodiment, it is preferable that the impression material 104 still contains a dispersant, which may widen the light direction of the light emitting component 102, resulting in an increased viewing angle. The impression material 104 has the lens function to focus or diffuse the light emitted by the light emitting component. Therefore, impression material 104 may be made in a convex or concave lens configuration, and may have an elliptical shape when viewed towards the optical axis, or a combination thereof. Also, molding material 104 may be made into a multilayer structure of different materials being laminated. As the impression material 104, transparent materials having high climate, such as epoxy resin, urea resin, silicone resin or glass are preferably employed. Such as dispersant, barium titanate, titanium oxide, aluminum oxide, silicon dioxide and the like can be used. In addition to the dispersant, the fluorescent material may also be contained in the impression material. Specifically, in accordance with the present invention, the fluorescent material may be contained in the impression material or in the coating material. When fluorescent material is contained in the impression material, the viewing angle may be increased further. The fluorescent material may also be contained in the coating material and the impression material. Further, a resin including fluorescent material may be used as the coating material, while using glass, other than the coating material, as the molding material. This makes it possible to manufacture a light emitting diode which is less subject to the influence of moisture with good productivity. Molding and coating may also be made of the same material to adapt the refractive index depending on the application. According to the present invention, the addition of the dispersant and / or a coloring agent in the impression material has the effects of masking the color of the obscured fluorescent material and improving the color mixing performance. That is, the fluorescent material absorbs the blue component of external light and emits light to thereby give it a yellow-like appearance. However, the dispersant contained in the impression material provides a milky white color to the impression material and the coloring agent interprets a desired color. Thus, the color of the fluorescent material will not be recognized by the observer. In case the light emitting component emits a light having a main wavelength of 430 nm or more, it is more preferable than an ultraviolet absorber, which serves as a light stabilizer, be contained.

Embodiment 2 The LED of the second embodiment of the present invention is made using an element provided with a gallium nitride compound semiconductor which has a high energy emission spectrum in the light emission layer. as a light-emitting component and a fluorescent material including two or more types of phosphorescent substances of different compositions, or preferably cerium-activated yttrium-aluminum-garnet fluorescent materials as the fluorescent material. With this configuration, a light emitting diode which allows to provide a desired color tone by controlling the contents of two or more fluorescent materials can be made even when the wavelength of the LED light emitted by the light emitting component deviates. the desired value due to variations in the production process. In this case, the emission color of the LED can be constantly made using a fluorescent material that has an actively short emission wavelength for a light emission component of a relatively short emission wavelength. and using a fluorescent material that has an actively long king emission wavelength for a light emission component of an actively long king emission wavelength, [00120] As for fluorescent material, a fluorescent material represented by the general formula (Re ^ rSm ^ Ali. sGas) 50O2: Ce can also be used as the fluorescent material, here, 0 <r <1 and 0 <s <1 and Re is at least one selected from Y, Gd and Over there. This configuration makes it possible to minimize the denaturation of the fluorescent material even when the fluorescent material is exposed to 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, and, therefore, a light emitting diode which is subject to extremely insignificant color deviation and emission decrease and has the desired high luminance emission component can be made. (Fluorescent Material of the Second Embodiment) Now, the fluorescent material in the light-emitting component of the second embodiment will be described in detail below. The second embodiment is similar to the first embodiment except that two or more types of phosphorescent substances of different cerium-activated compositions are used as the fluorescent material as described above, and the method of using the fluorescent material is basically the same.

Similar to the case of the first embodiment, the LED can be provided with high acclimatization by controlling the distribution of the fluorescent material (such as by tilting the concentration with the distance of the light-emitting component). Such a distribution of the concentration of fluorescent material can be achieved by selecting or controlling the material containing the fluorescent material, forming the temperature and viscosity, and the particle size configuration and distribution of the fluorescent material. Thus, according to the second embodiment, the concentration distribution of fluorescent material is determined according to the operating conditions. Also according to the second embodiment, the luminance emission efficiency may be increased by designing the arrangement of the two or more types of fluorescent materials (e.g., arranged in order of proximity to the light-emitting component) according to light generated by the light-emitting component.

With the configuration of the second embodiment, similar to the first embodiment, the LED has a high efficiency and a high light resistance even when disposed adjacent to or in the vicinity of a relatively high output light emitting component. irradiation intensity (Ee) in the range of 3 Wcm'2 to 10 Wcm "2.

The cerium-activated yttrium-aluminum-garnet fluorescent material (YAG fluorescent material) used in the second embodiment has a grenade structure similar to the case of the first embodiment, and is therefore resistant to heat, light and moisture. The excitation peak wavelength of the yttrium-aluminum-garnet fluorescent material of the second embodiment can be set near 450 nm, as indicated by the full line in figure 5A, and the peak emission wavelength can be set near 510 nm, as indicated by the solid line in figure 5B, while making the emission spectrum so wide as to reach 700 nm. This makes it possible to emit green light. The excitation peak wavelength of another cerium-activated yttrium-aluminum fluorescent material of the second embodiment can be set near 450 nm, as indicated by the dotted line in Figure 5A, and the peak wavelength of Emissions can be set close to 600 nm, as indicated by the dotted line in Figure 5B, while making the emission spectrum as wide as 750 nm. This makes it possible to emit red light.

The wavelength of emitted light is shifted to a shorter wavelength by substituting part of Al among the constituents of YAG fluorescent material having a grenade structure by Ga and the wavelength of light. emitted is shifted to a longer wavelength by replacing part of Y with Gd and / or La. The ratio of replacement of Al to Ga is preferably from Ga: AI = 1: 1 to 4: 6, in consideration of the luminous light efficiency and the emission wavelength. Similarly, the ratio of substitution of Y for Gd and / or La is preferably from Y: Gd and / or La = 9: 1 to 1: 9, or more preferably from Y: Gd and / or La = 4: 1 to 2: 3. Substitution of less than 20% results in a green component increase and a red component decrease. Replacing 80% or larger, on the other hand, increases the red component but decreases luminance sharply.

The fabrication material of such a fluorescent material is made using oxides of Y, Gd, Ce, La, Al, Sm and Ga or compounds which can easily be converted to such oxides at a high temperature and mixed with them. enough of these materials in stoichiometric proportions. Or, the mixing material is obtained by dissolving rare earth elements Y, Gd, Ce, La and Sm in stoichiometric proportions in an acid, co-precipitating the oxalic acid solution and burning the co-precipitate to obtain an oxide. of the co-precipitate, which is then mixed with aluminum oxide and gallium oxide. This mixture is mixed with an appropriate amount of a fluoride, such as an ammonium fluoride used as a flux, and burned in a crucible at a temperature of 1350 to 1450Ό in air for 2 to 5 hours. Then the burnt material is ground by a ball mill in water, washed, separated, dried and sieved to thereby obtain the desired material.

In the second embodiment, the two or more types of cerium-activated yttrium aluminum - garnet fluorescent materials of different compositions may be used by mixing or independently disposed (laminates, for example). When the two or more types of fluorescent materials are mixed, a color conversion portion may be formed relatively easily and in a manner suitable for mass production. When the two or more types of fluorescent materials are independently arranged, the color may be adjusted after formation by lamination of the layers until a desired color can be obtained. Also, when arranging the two or more types of fluorescent materials independently, it is preferable to have a light-absorbing fluorescent material of the shorter wavelength light-emitting component near the LED element, and a light-absorbing fluorescent material. of a longer wavelength away from the LED element. This arrangement allows for efficient absorption and emission of light.

The LED of the second embodiment is made using the two or more types of yttrium-aluminum-garnet fluorescent materials of different compositions as the fluorescent materials, as described above. This makes it possible to make a light-emitting diode capable of emitting light of the desired color efficiently. That is, when the wavelength of light emitted by the semiconductor light-emitting component corresponds to a point on the straight line connecting point A and point B in the chromaticity diagram of figure 6, the light of any color in the marked region. surrounded by points A, B, C and D in figure 6, which is the chromaticity points (points C and D) of the two or more types of yttrium - aluminum - garnet fluorescent materials of different compositions which can be emitted. According to the second embodiment, the color may be controlled by changing the compositions or amounts of the LED elements and fluorescent materials. In particular, a smaller emitting wavelength light emitting diode may be made by selecting the fluorescent materials according to the emitting wavelength of the LED element, thereby compensating for the emitting wavelength variation. of the LED element. Also, an LED including high luminance RGB components can be made by selecting the emission wavelength of fluorescent materials.

Further, because the yttrium-aluminum-garnet (YAG) fluorescent material used in the second embodiment has a grenade structure, the LED of the second embodiment can emit high luminance light for a long period of time. Also, the light-emitting diodes of the first and second embodiments are provided with a light-emitting component installed via a fluorescent material. Also, because the converted light has a longer wavelength than that of light emitted by the light-emitting component, the energy of the converted light is smaller than the nitride semiconductor bandwidth, and is less likely to be. absorbed by the nitride semiconductor layer. Thus, while the light emitted by the fluorescent material is also directed to the LED element because of emission isotropy, the light emitted by the fluorescent material is never absorbed by the LED element and therefore the light efficiency of the LED does not. will be decreased. (Flat light source) [00130] A flat light source which is another embodiment of the present invention is shown in Figure 7. In the flat light source shown in Figure 7, the fluorescent material used in the first embodiment. or in the second embodiment is contained in a coating material 701. With this configuration, the blue light emitted by the gallium nitride semiconductor is color converted and is extracted in a flat state via an optical guide plate 704 and a dispersive sheet 706 .

Specifically, a light-emitting component 702 of the flat light source of Figure 7 is attached to an inverted C-shaped metal substrate 703 where an insulation layer and conductive pattern (not shown) are formed. . After the light-emitting component and conductive pattern electrode is electrically connected, the fluorescent material is mixed with epoxy resin and applied to the inverted C-shaped metal substrate 703, where the light-emitting component 702 is mounted. The light-emitting component secured in this manner is fixed to an end face of an acrylic optical guide plate 704 by means of an epoxy resin. A reflective film 707 containing a white diffusion agent is disposed on one of the main planes of the optical guide plate 704 where the dispersive sheet 706 is not formed in order to prevent fluorescence.

Similarly, a reflector 705 is provided on the entire surface behind the optical guide plate 704 and on an end face where the light emitting component is not provided, in order to improve the light efficiency of light. With this configuration, the light emitting diodes, which generate sufficient luminance for the LCD backlight, can be made.

[00134] An application of the flat light emission LED to a liquid crystal display can be accomplished by arranging a polarizer plate on a main plane of the optical guide plate 704 via a liquid crystal injected between glass substrates. (not shown) about which a translucent conductive pattern is formed.

Referring to Figure 8 and Figure 9, a flat light source according to another embodiment of the present invention will be described below. The LEDs shown in Figure 8 are made of a configuration such that the blue light emitted by LEDs 702 is converted to white light by a color converter 701 which contains the fluorescent material and is extracted in a flat state via an optical guide plate 704.

The light emitting device shown in Figure 9 is made of a configuration such that the blue light emitted by the light emitting component 702 is transformed to the flat state by the optical guide plate 704, then converted to white light by a dispersive sheet 706 which contains the fluorescent material formed on one of the main planes of the optical guide plate 704, thereby extracting flat state white light. The fluorescent material may be contained in the dispersive sheet 706 or may be formed into a sheet by spraying together with a binder resin onto the dispersive sheet 706. Further, the binder including fluorescent material may be formed in points, not sheet, directly onto the surface. optical guide plate 704. <Application> fDisplay Device) A display device according to the present invention will now be described below. Figure 10 is a block diagram showing the configuration of the display device according to the present invention. As shown in Figure 10, the display device comprises an LED display device 601 and a drive circuit 610 having a driver 602, a video data storage means 603 and a tone control means 604. The display device LED display 601, which has white light-emitting diodes 501 shown in Figure 1 or Figure 2 arranged in a matrix configuration in a housing 504, as shown in Figure 11, is used as a monochrome LED display device. The housing 504 is provided with a light blocking material 505 being integrally formed therewith.

Drive circuitry 610 has video data storage (RAM) means 603 for temporary storage of display data which is input from tone control means 604 which computes and extracts tone signals for control of the individual LEDs of the LED display 601 to light up to the specified brightness according to the RAM 603 read value, and the trigger 602, which is switched by signals supplied from the tone control means 604 to Turn on the LED to light up. Tone control circuit 604 retrieves data from RAM 603 and computes the LED's duration from LED 601, then extracts pulse signals to turn LEDs on and off for display device In the display device constituted as described above, the LED display device 601 is capable of displaying images according to pulse signals which are input from the drive circuit, and has the following advantages.

[00139] The LED display device, which displays white light using the three-color RGB LEDs, is required to display while controlling the light output of the R, G and B, therefore, the light-emitting diodes should be controlled by taking into account the emission intensity, temperature characteristics and other factors of the light-emitting diodes, resulting in a complicated drive circuit configuration that triggers the LED display device. In the display device of the present invention, however, because the LED emitting device 601 is constituted using the light emitting diodes 501 of the present invention, which can emit white light without using three types of light emitting diodes, RGB, It is not necessary for the drive circuit to individually control the R, G and B LEDs, making it possible to simplify the drive circuit configuration and make the display device at a low cost.

With the LED display device displaying in white light using three types LEDs, RGB, the three LEDs should be illuminated at the same time and the light from LEDs should be mixed. to display white light by combining the three RGB LEDs for each pixel, resulting in a large display area for each pixel and making high definition display impossible. The LED display device of the display device according to the present invention, in contrast, can display with white light, can be made with a single LED and therefore is capable of a definition white light display. taller. Also, with the LED display device that displays by mixing the colors of the three LEDs, there is the case that the display color changes due to the blocking of part of the RGB LEDs, depending on the viewing angle, the device LED display screen of the present invention having no such problem.

As described above, the display device provided with the LED display device employing the LED of the present invention which is capable of emitting white light is capable of displaying stable white light with a higher definition and has the advantage of less color inequality. The LED display device of the present invention which is capable of white light display also imposes less stimulation on the eye compared to the conventional LED display device which employs only red and green colors, and is therefore suitable for use for a long time.

[00142] (Realization of another display device employing the LEDs of the present invention) [00143] The LEDs of the present invention may be used to constitute an LED display device where a pixel consists of three RGB light-emitting diodes and a light-emitting diode of the present invention as shown in FIG. 12. By connecting the LED display device and a specific drive circuit, the display device capable of displaying multiple images can be constituted. The drive circuit of this display device has, similar to the monochrome display device, a video data storage (RAM) means for temporarily storing input display data, a tone control circuit which processes the data stored in RAM to compute the tone signals to light up the specific brightness LEDs and a trigger which is switched by the tone control circuit output signal to make the LEDs light up . The drive circuit is required exclusively for each of the RGB LEDs and the white LED. The tone control circuit computes the illumination duration of the LEDs from the data stored in RAM, and extracts pulse signals for turning the LEDs on and off, When displaying with white light, the width of the pulse signals for lighting the LEDs is shorter, or the peak value of the pulse signal is made smaller or smaller. no pulse signal is extracted at all. On the other hand, a pulse signal is given to the white light emitting diode in compensation. This causes the LED display device to display with white light.

[00144] As described above, the display brightness can be enhanced by adding LEDs to RGB LEDs. When RGB LEDs are combined to display white light, one or more of the RGB colors can be increased, resulting in a failure to display pure white depending on the viewing angle, a problem such as this being solved by adding the LED as in this display device.

For the drive circuit of such a display device as described above, it is preferable that a CPU be provided separately as a tone control circuit which computes the pulse signal for LED illumination. white with the specific brightness. The pulse signal which is extracted from the tone control circuit is provided to the white LED driver to thereby switch the trigger. The white LED illuminates when the trigger is on and goes out when the trigger is off. (Traffic Signal) When the LED of the present invention is used as a traffic signal, which is a type of display device, advantages such as stable illumination for a long period of time and no color inequality even when part of the LEDs go out.The traffic signal employing the LED of the present invention has a configuration such that the white LEDs are arranged on a substrate where a conductive pattern A light-emitting diode circuit where these light-emitting diodes 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 spiral conjugations.When all the light-emitting diodes are arranged, they are arranged over the entire area in one configuration. After the welding power lines are connected for connecting the light-emitting diodes and the substrate to the external power supply, it is attached to a railroad signal chassis. The LED display is placed in a die-cast aluminum chassis equipped with a light-blocking element and is surface sealed with a silicone rubber pad. The chassis is provided with a white lens in its view plane. Electrical wiring of the LED display device is passed through a rubber housing at the rear of the chassis to seal the inside of the outside chassis with the inside of the chassis closed. Thus, a white light signal is made. A higher reliability signal may be made by dividing the light-emitting diodes of the present invention into a plurality of groups and arranging them in a swirling spiral configuration from the center to the outside while being connected in parallel. The center outward swirl configuration can be done continuously or intermittently. Therefore, the desired number of light-emitting diodes and the desired number of light-emitting diode assemblies can be selected depending on the display area of the LED display device. This signal is, even when one of the light-emitting diode assemblies or part of the light-emitting diodes fails to illuminate due to some problem, able to illuminate evenly in a circular configuration without color deviation through the remaining set of light-emitting diodes. remaining light or LEDs. Because light-emitting diodes are arranged in a spiral configuration, they may be denser arranged in the center and driven without any different impression from the signals employing incandescent lamps. <Examples>

The following Examples illustrate the present invention in greater detail, but should not be construed as limiting the scope thereof. (Example 11) Example 1 provides a light-emitting component that has an emission peak at 450 nm and a half width of 30 nm using a GalnN semiconductor. The light-emitting component of the present invention is made by flowing TMG (trimethyl gallium) gas, TMI (trimethyl indium) gas, nitrogen gas and coating gas together with a carrier gas on a clean sapphire substrate and forming a semiconductor layer of gallium nitride compound in the MOCVD process. A gallium nitride semiconductor having an N-type conductivity and a gallium nitride semiconductor having a P-type conductivity are formed by alternating SiH4 and Cp2Mg as the doping gas.The LED element of Example 1 has a layer of contact which is a gallium nitride semiconductor having an N-type conductivity, a shielding layer which is a gallium nitride aluminum semiconductor having P-type conductivity, and between the conductive contact layer N-type activity and the P-type conductivity shielding layer is formed of an undoped doped InGaN activation layer of about 3 nm for making a single quantum well structure. The sapphire substrate has a gallium nitride semiconductor layer formed at a low temperature to make a temporary storage layer. The P-type semiconductor is annealed at a temperature of 400Ό or more after film formation.

Following exposure of the surfaces of the P-type and N-type semiconductor layers by chemical etching, the n and p electrodes are formed by chemical deposition. After scratching the semiconductor wafer which was made as described above, the light emitting components are made by dividing the wafer with an external force.

The light-emitting component made in the above process is mounted in a housing of a mounting wire which is made of silver-coated steel by an epoxy resin matrix bond. Then the light emitting component electrodes, the mounting wire and the inner wire are electrically connected by wire bonding to the 30 pm diameter gold wires to make a conductor type LED.

A fluorescent material is made by dissolving rare earth elements of Y, Gd and Ce in an acid in stoichiometric proportions, and co-precipitating the solution with oxalic acid. The co-precipitated oxide obtained by burning this material is mixed with aluminum oxide to obtain the mixing material. The mixture was then mixed with ammonium fluoride used as a stream, and burned in a crucible at a temperature of 1400Ό in air for 3 hours. Then the burnt material is milled by a ball mill in water, washed, separated, dried and sieved to thereby obtain the desired material. The fluorescent material made as described above is a yttrium-aluminum-garnet fluorescent material represented by the general formula (Y0.8Gdo, 2) 3AI5O2: Ce, where about 20% of Y is replaced by Gd and the replacement ratio of Ce is 0.03.

80 parts by weight of the fluorescent material having a composition of (Yo.eGdo ^ sAlsO ^ iCe, which was made in the above process, and 100 parts by weight of epoxy resin are sufficiently mixed to turn into a slurry. mud is poured into the enclosure provided in the mounting wire where the light-emitting component is mounted.After the leakage, the mud is cured at 130 ° for one hour, thus a coating having a thickness of 120 pm which contains the material. fluorescent, is formed in the light-emitting component.In Example 1, the coating is formed to contain the fluorescent material by gradually increasing concentration towards the light-emitting component.The irradiation intensity is about 3.5 W / The light-emitting component and the fluorescent material are molded with a translucent epoxy resin for protection against external stress, moisture and dust. Fluorescent material formed on it is placed in a projectile-shaped matrix and mixed with a translucent epoxy resin and then cured at 150 ° for 5 hours.

Upon visual observation of the LED formed as described above in the normal direction to the light emission plane, it was found that the central portion was interpreted as yellowish due to the body color of the fluorescent material.

The chromaticity point, color temperature and color interpretation index measurements of the light emitting diode made as described above and capable of emitting white light gave values of (0.302, 0. 280) for the chromaticity point. (x, y), 8080 K color temperature and 87.5 for the color interpretation index (Ra), which approximates the characteristics of a waveform 3 fluorescent lamp. 9.5 Im / W, comparable to that of incandescent light, Still in service life under power conditions with a current of 60 mA at 250, 20 mA at 250 and 20 mA at 600 with 90% RH, no changes due to the fluorescent material was observed, proving that the LED had no difference in service life from the conventional blue LED, (Comparative Example 1) [00155] The formation of an LED and the tests same were conducted in the same way as Example 1, except for the change of fluorescent material from (Yo, aGdo, 2) 3AI5Oi2: Ce to (ZnCd) S: Cu, Al. The light-emitting diode, which had been formed, showed, immediately after energization. , an emission of white light, but with low luminance. In a lifetime test, the output decreased to zero by about 100 hours. Analysis of the cause of deterioration showed that the fluorescent material was darkened.

This problem is supposed to have been caused by light emitted by the light-emitting component, and moisture that had been retained in the fluorescent material or entered outside generated a photolysis to cause the coioidal zinc to fade. precipitate on the surface of the fluorescent material, resulting in a darkened surface. The results of the service life tests under energizing conditions with a current of 20 mA at 250 and 20 m A at 600 with 90% RH are shown in Figure 13 together with the results of Example 1. The luminance is given in terms of relative value relative to the initial value as a reference. A solid line indicates Example 1 and a dashed line indicates Comparative Example 1 in Figure 13. (Example 2) In Example 2, a light-emitting component was made in the same manner as in Example 1 except for the increase. Installation of the light emitting component nitride compound semiconductor content to have an emission peak at 460 nm and increasing the Gd content in the fluorescent material more than that of Example 1 to have a composition of ( Yo 16Gdo, 4) 3AI5012: Ce.

Measurements of the chromaticity point, color temperature and color transformation index of the light-emitting diode, which were made as described above and capable of emitting white light, gave values of (0.375, 0.370). for chromaticity point (x, y), 4400 K color temperature and 86.0 for color interpretation index (Ra), Figure 18A, Figure 18B and Figure 18C show material emission spectra. fluorescent light of the light emitting component and the LED of Example 2, respectively.

100 pieces of light emitting diodes from Example 2 were made and the light intensities thereof were taken after an illumination for 1000 hours. In terms of percentage of the light intensity value before the service life test, the average light intensity after the service life test was 98.8%, showing no difference in characteristic (Example 3). were made in the same manner as in Example 1, except for the addition of Sm in addition to the rare earth elements Y, Gd and Ce in the fluorescent material to make a fluorescent material of the composition of (YojgGdo, syCeo.os Smo). When the light-emitting diodes were lit at a high temperature of 130 ° C, an average temperature characteristic of about 8% better than that of Example 1 was obtained (Example 4). The LED display device of Example 4 is made of the LEDs of Example 1 being arranged in a 16 x 16 matrix on a ceramic substrate where a copper pattern is formed, as shown in Figure 11. In the LED display device Example 4 LED, the substrate The act where the light-emitting diodes are arranged is placed on a chassis 504 which is made of phenolic resin and is provided with a light blocking element 505 being integrally formed therewith. The chassis, light-emitting diodes, substrate and part of the light-blocking element, except for the tips of the light-emitting diodes, are covered with a black pigment-coated 506 silicone rubber. The substrate and light-emitting diodes are welded by means of an automatic welding machine.

The LED display device made in the configuration described above, a RAM which temporarily stores the input display data, the tone control circuit which processes the data stored in RAM to compute tone signals to light up the signals. LEDs with a specific brightness, and a drive means, which is switched by the tone control circuit output signal to make the LEDs light up, are electrically connected to make a display device LED light. By activating the LED display devices, it has been found that the apparatus can be used as a black and white LED display device. (Example 5) The LED of Example 5 was made in the same manner as in Example 1 except for the use of fluorescent material represented by the general formula (Υο. ^ Όο, δ ι 2: Ce. 100 pieces of diodes The light emitters of Example 5 were made and measured for various characteristics.

Chromaticity point measurement gave values of (0.450, 0.420) on average for 0 chromaticity point (x, y), and incandescent lamp color light was emitted. Figure 19A, Figure 19B and Figure 19C show the emission spectra of the fluorescent material of the light emitting component of the LED of Example 5, respectively. Although the light-emitting diodes of Example 5 showed luminance about 40% lower than that of the light-emitting diodes of Example 5, they showed good weathering comparable to that of Example 1 in the service life test. (Example 6) The LED of Example 6 was made in the same manner as in Example 1, except for the use of the fluorescent material represented by the general formula YaAlgO4 Ce. 100 pieces of the LEDs of Example 6 were made and measured for various characteristics.

In the chromaticity point measurement a slightly yellowish greenish white light was emitted compared to Example 1. The LED of Example 6 showed good climate similar to that of Example 1 in the service life test. Figure 20A, Figure 20B and Figure 20C show the emission spectra of the fluorescent material, light-emitting component and LED of Example 6, respectively. (Example 7) The LED of Example 7 was made in a similar manner to Example 1 except for the use of the fluorescent material represented by the general formula Y3 (Alo, 5Ga0.5) 50ϊ2: Ce. 100 pieces of the LEDs of Example 7 were made and measured for various characteristics.

Although the light-emitting diodes of Example 7 showed a low luminance, they emitted a greenish white light and showed good climate similar to that of Example 1 in lifetime testing. Figure 21A, Figure 21B and Figure 21C show the emission spectra of the fluorescent material, light emitting component and LED of Example 7, respectively.

[Example 8] The LED of Example 8 was made in the same manner as in Example 1, except for the use of fluorescent material represented by the general formula Gd3 (Al0.5Gao, 5) 50i2: Ce, which is not contains Y, 100 pieces of the Example 8 LEDs have been made and measured for various characteristics.

Although the light-emitting diodes of Example 8 showed a low luminance, they showed good climate similar to that of Example 1 in the service life test. (Example 9) The LED of Example 9 is a flat light emitting device having the configuration shown in Figure 7.

[00172] A ln0.05Gao, 95N semiconductor having an emission peak at 450 nm is used as a light emission component. Light-emitting components are made by flowing TMG (trimethyl gallium) gas, TMI (trimethyl indium) gas, nitrogen gas and coating gas together with a carrier gas on a clean sapphire substrate and forming a semiconductor layer of compound. of gallium nitride in the MOCVD process. A gallium nitride semiconductor layer having an N-type conductivity and a gallium nitride semiconductor layer having a P-type conductivity are formed by alternating SiH4 and Cp2Mg as the coating gas, thereby forming a PN junction. For the semiconductor light-emitting component, a contact layer which is a gallium nitride semiconductor having an N-type conductivity, a shield layer which is a gallium nitride aluminum semiconductor having N-conductivity , a shielding layer which is a gallium nitride aluminum semiconductor having P-type conductivity and a contact layer which is a gallium nitride semiconductor having P-type conductivity are formed. A Zn coated InGaN activation layer which forms a double straight junction is formed between the N-type conductivity shield layer and the P-type conductivity shield layer. A temporary storage layer is provided. in the sapphire substrate by the formation of the gallium nitride semiconductor layer at a low temperature. The P-type nitride semiconductor layer is annealed at a temperature of 400Ό or more after film formation.

Following formation of semiconductor layers and exposure of surfaces of P-type and N-type semiconductor layers by chemical attack, the electrodes are formed by vacuum evaporative deposition. After scratching the semiconductor wafer, which was made as described above, the light emitting components are made as light emitting components by dividing the insert with an external force.

The light-emitting component is mounted on a mounting wire which has a housing on the tip of a silver-coated copper wire frame by matrix bonding with epoxy resin. The light-emitting component, mounting wire, and inner wire electrodes are electrically wired by gold wire having a diameter of 30 pm.

The wire frame with the light-emitting component affixed to it is placed in a capsule-shaped matrix and sealed with a translucent molding epoxy resin, which is then cured at 150 ° for 5 hours to thereby form a blue light emitting diode. The blue LED is connected to one end face of an acrylic optical guide plate which is polished on all end faces. On one surface and one side of the acrylic plate, a screen print is applied using barium titanate dispersed in an acrylic binder as a white light reflector, which is then cured.

Green and red phosphorescent substances are made by dissolving rare earth elements of Y, Gd, Ce and La in acid in stoichiometric proportions, and co-precipitating the solution in oxalic acid. The co-precipitated oxide obtained by burning this material is mixed with aluminum oxide and gallium oxide to thereby obtain the respective mixing materials. The mixture is then mixed with ammonium fluoride used as a stream and burned in a crucible at a temperature of 1400Ό in air for 3 hours. Then the burnt material is milled by a ball mill in water, washed, separated, dried and sieved to thereby obtain the desired material.

120 parts by weight of the first fluorescent material having a composition of Y3 (AI 0.6Ga 0.4) 50 O2: Ce and capable of emitting green light prepared as described above and 100 parts by weight of the second fluorescent material having a composition of ( Yo, 4Gdo, 6) 3Al50i2: Ce and capable of emitting red light prepared in a process similar to that for the first fluorescent material are sufficiently mixed with 100 parts by weight of epoxy resin to form a slurry. The slurry is uniformly applied to an acrylic layer having a thickness of 0.5 mm by means of a multiple coating agent, and dried to form a fluorescent material layer for use as a color conversion material having a thickness of about from 30 pm. The fluorescent material layer is cut to the same size as that of the main light emission plane of the optical guide plate, and arranged on the optical guide plate to thereby form the flat light emission device. Chromaticity point and color interpretation index measurements gave values of (0.29, 0.34) for the chromatography point (x, y) and 92.0 for color interpretation index (Ra). , which are close to the properties of waveform fluorescent lamp 3. The light efficiency of 12 Im / W comparable to that of an incandescent lamp was obtained. Also, in climatization tests under normal energizing conditions with a current of 60 mA at room temperature, 20 mA at room temperature and 20 mA at 60Ό with 90% U.R., no change due to fluorescent material was observed. (Comparative Example 2) The formation of the LED and its climate tests were conducted in the same manner as in Example 9, except for the mixing of the same amounts of a green organic fluorescent pigment (FA-QÜ1 from Synleuch). Chemisch) and a red organic fluorescent pigment (FA-005 from Synleuch Chemisch), which are derived from perylene, rather than the first fluorescent material represented by the general formula Y3 (Al0.6Gao.4) sOi2: Ce capable of emitting green light. and the second fluorescent material represented by the general formula (Yo4Gdoi6) 3AI5012: Ce capable of emitting red light from Example 9. The chromaticity coordinates of the LED of Comparative Example 1 thus formed were (x, y) = (0.34 , 0.35), The HVAC test was conducted by irradiation with an ultraviolet ray generated by carbon arc for 200 hours, representing an equivalent irradiation of sunlight for a period of one year, while measuring air. luminance retention relationship and color tone at various times during the test period. In a reliability test, the light emitting component was 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, together with Example 9. As will be clear from Figure 14 and Figure 15, the light-emitting component of Example 9 experiences less deterioration than that of Comparative Example. 2. (Example 101) The LED of Example 10 is a conductor type LED.

In the LED of Example 10, the light-emitting component having an Ino.osGao.asN light-emitting layer with an emission peak at 450 nm, which is made in the same manner as in the Example. 9, is used. The light-emitting component is mounted on the housing provided at the end of a silver-coated copper mounting wire by matrix bonding with epoxy resin. The light emitting component, mounting wire, and inner wire electrodes are electrically connected by gold-wire bonding.

The fluorescent material is made by mixing a first fluorescent material represented by the general formula Y3 (AloisGa0i5) g012iCe capable of emitting green light and a second fluorescent material represented by the general formula (Y0.2Gdo, 8) 3AI5Oi2: Ce capable emit red light prepared as follows. Specifically, the rare earth elements of Y, Gd and Ce are dissolved in acid in stoichiometric proportions, and the solution is co-precipitated with oxalic acid. The co-precipitation oxide obtained by burning is mixed with aluminum oxide and gallium oxide to thereby obtain the respective mixing materials. The mixture is then mixed with ammonium fluoride used as a stream, and burned in a crucible at a temperature of 1400Ό in air for 3 hours. Then the burnt material is milled by a ball mill in water, washed, separated, dried and sieved to thereby obtain the first and second fluorescent materials of the specified particle size distribution.

40 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 are sufficiently mixed to form a slurry. Mud is poured into the housing which is provided in the mounting wire where the light emitting component is placed. Then the resin including fluorescent material is cured at 130 ° for 1 hour. Thus, a coating layer including the 120 µm thick fluorescent material is formed on the light emitting component. The concentration of fluorescent material in the coating layer is gradually increased toward the light emitting component. In addition, the light-emitting component and fluorescent material are sealed by molding with a translucent epoxy resin for protection against external stress, moisture and dust. A wire frame with the fluorescent coating layer formed thereon is placed in a capsule-shaped matrix and mixed with the translucent epoxy resin and then cured at 150 ° for 5 hours. Under visual observation of the LED formed as described above in the normal direction to the light emission plane, it was found that the central portion was interpreted as yellowish in color due to the body color of the fluorescent material.

The chromaticity point, color temperature and color interpretation index measurements of the LED of Example 10, which is made as described above, gave values of (0.32, 0.34). for the chromaticity point (x, y), 89.0 for the color interpretation index (Ra) and a luminous light efficiency of 10 Im / W. Still in the climatization tests under normal energization conditions with a current of 60 mA at room temperature, 20 mA at room temperature and 20 mA at 60Ό with 90% RH, no change due to the fluorescent material was observed, showing no difference of a common blue LED in service life feature. (Example 11) An ln0,4Ga0,6N semiconductor having an emission peak at 470 nm is used as an LED element. Light-emitting components are made by flowing TMG (trimethyl gallium) gas, TMI (trimethyl indium) gas, nitrogen gas and coating gas together with a carrier gas on a clean sapphire substrate and forming a semiconductor layer of compound. of gallium nitride in the MOCVD process. A gallium nitride semiconductor layer having an N-type conductivity and a gallium nitride semiconductor layer having a P-type conductivity are formed by alternating SiH4 and Cp2Mg as the coating gas, thereby forming a PN junction. For the LED element, a contact layer, which is a gallium nitride semiconductor having N-type conductivity, a shield layer which is a gallium nitride aluminum semiconductor having P-type conductivity, and a Contact layer which is a gallium nitride semiconductor having a P-type conductivity are formed. An uncoated InGaN activation layer about 3 nm thick is formed between the N-type conductivity contact layer and the P-type conductivity shield layer. A temporary storage layer is provided on the substrate. sapphire by forming the gallium nitride semiconductor layer at a low temperature.

Following layer formation and exposure of P-type and N-type surfaces of chemical etching semiconductor layers, the electrodes are formed by cathodic deposition. After scratching the semiconductor wafer, which is made as described above, the light-emitting components are made by dividing the wafer with an external force.

The light-emitting component is mounted in a housing on the tip of an epoxy resin matrix bonded silver-plated copper mounting wire. The light-emitting component, mounting wire, and inner wire electrodes are electrically connected by gold-wire wire bonding having a diameter of 30 pm.

The wire frame with the light-emitting component affixed thereto is placed in a capsule-shaped matrix and sealed with a translucent molding epoxy resin, which is then cured at 150 ° for 5 hours to thereby form a blue light emitting diode. The blue LED is connected to one end face of an acrylic optical guide plate which is polished on all end faces. On one surface and one side of the acrylic plate, a screen print is applied using barium titanate dispersed in an acrylic binder as a white light reflector, which is then cured.

The fluorescent material is made by mixing a fluorescent material represented by the general formula (Yo.sGdo ^ AlOO- ^ Ce capable of emitting relatively short wavelength yellow light and a fluorescent material represented by the general formula (Yo, 4Gd016 ) 3AI5Oi2: Ce capable of emitting relatively long wavelength yellow light prepared as follows: Specifically, the rare earth elements of Y, Gd and Ce are dissolved in an acid in stoichiometric proportions, and co-precipitating the solution with oxalic acid The co-precipitation oxide obtained by burning is mixed with aluminum oxide to obtain the respective mixing material The mixture is then mixed with ammonium fluoride used as a flux and burned to a crucible. at 1400 ° C in air for 3 hours Then the burnt material is milled by a ball mill in water, washed, separated, dried and sieved.

100 parts by weight of relatively short wavelength yellow fluorescent material and 100 parts by weight of relatively long wavelength yellow fluorescent material, which are made as described above, are sufficiently mixed with 1000 parts by weight of acrylic resin and extruded, to thereby form a fluorescent film of material to be used as a color conversion material of about 180 µm thickness. The fluorescent film is cut to the same size as the main emission plane of the optical guide plate and disposed on the optical guide plate to thereby make a light emitting device. Chromaticity point and color interpretation index measurements of the light emitting device of Example 3, which is made as described above, gave values of (0.33, 0.34) for the chromaticity point (x, y), 88,0 for the color interpretation index (Ra) and a light efficiency of 10 Im / W. Figure 22A, Figure 22B, and Figure 22C show emission spectra of the fluorescent material represented by (Yo.eGdtuJsAlsO ^ Ce and fluorescent material represented by the general formula (Yo ^ GdoehAIsQi ^ Ce used in Example 11. Figure 23 shows an emission spectrum of the light emitting diode of Example 11. Also, in the lifetime tests under energizing conditions with a current of 60 mA at room temperature, 20 mA at room temperature and 20 mA at 60Ό with 90% RH No change due to fluorescent material has been observed Similarly, the desired chromaticity can be maintained even when the wavelength of the light-emitting component is changed by changing the content of the fluorescent material (Example 12). ] The light emitting diode of Example 12 was made in the same manner as in Example 1, except for the use of the fluorescent material represented by the general formula Y3ln50i2: Ce 100 pieces of the light emitting diode of Example 12 were made. When the LED of Example 12 showed a luminance lower than that of the LEDs of Example 1, it showed good air conditioning comparable to that of Example 1 in the service life test.

As described above, the LED of the present invention can emit light of a desired color and is subject to less deterioration of light efficiency and good climate even when used at high luminance for a long period of time. Therefore, the application of the LED is not limited to electronic applications, but may open new applications including a display for automobiles, aircraft and buoys for bays and ports, as well as outdoor use such as a sign and lighting for expressways.

Claims (22)

1. White light-emitting device, comprising: wires (105, 205), an LED chip (102, 202) that emits visible light and is mounted on wire (105), the LED chip having a semiconductor layer. N-type nitride and a N-type nitrite semiconductor layer and N and P electrodes formed on exposed surfaces of the P-type nitrite semiconductor layer and the N-type nitride semiconductor layer, a transparent material (101, 201) covering said LED chip (102, 202), and a fluorescent material contained in the transparent material and absorbing a portion of the light emitted by the LED chip and emitting light with a longer main emission wavelength than that the main emission peak of the LED chip (102, 202), wherein the main emission peak of the LED chip (102, 202) is in the range of 420 nm to 490 nm, and characterized by the fact that the chip LED is a downward facing type and both LED chip N and P electrodes are electrically connected and attached to the wire by a metal paste, Ag paste or carbon paste. Light-emitting device according to Claim 1, characterized in that the light emitted by the fluorescent material is reflected by another particle of the fluorescent material and is further reflected by the surface of said wire. Light-emitting device according to claim 1, characterized in that the surface of said wire is polished and mirrored. Light-emitting device according to Claim 1, characterized in that the wire has a surface roughness of not less than 0,1 If not more than 0,8 S. Light-emitting device according to claim 1, characterized in that a plurality of said LED chips are mounted on said wire. Light-emitting device according to claim 1, characterized in that the thermal conductivity of said wire is not less than 0.01 cal / s (cm2) (° C / cm). Light-emitting device according to claim 1, characterized in that said wire comprises a material selected from the group consisting of steel, copper, copper-coated steel, copper-coated tin and metallized ceramic. Light-emitting device according to claim 1, characterized in that said wire comprises metallized ceramic. Light-emitting device according to claim 1, characterized in that said substrate is sapphire. Light emitting device according to claim 1, characterized in that said LED chip emits light with a spectrum with a peak in the range of 420 to 490 nm, the fluorescent material emits light with a spectrum of a peak in the range of 510 to 600 nm and a tail extending beyond 700 nm, said spectrum of light emitted from fluorescent material and spectrum of light emitted from the LED chip overlap to create a continuous combined spectrum. Light-emitting device according to Claim 10, characterized in that said spectrum of light emitted from the fluorescent material has a peak in the range of 530 to 570 nm and a tail extending beyond 700 nm. Light-emitting device according to claim 10, characterized in that the color of said combined spectrum is white. Light-emitting device according to claim 1, characterized in that the fluorescent material comprises two or more types of fluorescent materials. Light-emitting device according to claim 1, characterized in that the fluorescent material comprises a cerium-activated garnet fluorescent material containing at least one element selected from Y, Lu, Sc, La, Gd and Sm is at least one element selected from Al, Ga, and In. Light-emitting device according to claim 1, characterized in that the fluorescent material comprises a Y-Al-containing yttrium-aluminum garnet fluorescent material and the fluorescent material still has a crystal structure. Light-emitting device according to claim 1, characterized in that the fluorescent material diffuses light emitted from said LED chip. A light emitting device according to claim 1, characterized in that said LED chip comprises a light emission layer of single or multiple quantum well structure. Light-emitting device according to claim 1, characterized in that said LED chip comprises InGaN. Light-emitting device according to Claim 1, characterized in that said transparent material is selected from the group consisting of epoxy resin, urea resin, silicone resin and glass. Light-emitting device according to claim 1, characterized in that the transparent material contains a dispersant. Backlight source comprising a light-emitting device as defined in any one of claims 1 to 20. A liquid crystal display comprising a backlight source as defined in claim 21 and a liquid crystal injected between glass substrates.