JP2004079933A - Led display, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an LED display having an environmental resistance and a high reliability, and the manufacturing method thereof wherein the lights of the three primary colors of red (R), green (G), and blue (B) can be emitted at a very fine light emitting space smaller than 1 mm, and the light emitting intensities of the respective colors are made high, and further, an arbitrary color can be displayed. <P>SOLUTION: Light emitting layers 2R, 2G, 2B for emitting respectively the lights of red (R), green (G), and blue (B) are provided adjacently to each other at a fine pitch on a single substrate. Also, the light emitting regions of blue (B), green (G), and red (R) are set adjacently to each other at a fine pitch on a single substrate, and the light emitting layers (2R, 2G, 2B) for emitting the respective color lights are formed in the respective light emitting regions successively or at the same time. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an LED display that emits three primary colors of red (R), green (G), and blue (B) to display an arbitrary color, and a method of manufacturing the same.
[0002]
[Prior art]
Conventionally, different materials are used for the light emitting layer of the LED display depending on the emission color. For example, red (R) is InGaAs or InGaP, green (G) is GaP, InGaAs or InGaN, and blue (B) is InGaN. Therefore, the conventional LED display performs multi-color display by a method in which a large number of LED elements molded for each of R, G, and B emission colors are arranged. Such an LED display has already been put to practical use, for example, as a large outdoor display.
[0003]
[Problems to be solved by the invention]
The conventional LED display described above has a problem that a high-definition display cannot be provided because a large number of molded LED elements are arranged for each of R, G, and B emission colors.
[0004]
In order to solve this problem, a 3-in-1 full-color LED as schematically shown in FIG. 5 has been put to practical use. This 3-in-1 full-color LED is a multi-chip type lamp in which three LED chips of each color of RGB are mounted on a lead frame, and a total of three LED chips are sealed with epoxy. The light radiated from each chip is mixed in the molded lens and becomes one color and is taken out. By adjusting the current flowing through each chip to an appropriate ratio, the amount of light emitted from the red, green, and blue chips can be changed to perform full-color color expression.
[0005]
FIG. 6 is a schematic perspective view of an LED display using the above-described 3-in-1 full-color LED. As shown in this figure, by arranging a large number of 3-in-1 full-color LEDs vertically and horizontally on a single panel, a large planar LED display can be easily configured.
[0006]
However, since the size of the 3-in-1 full-color LED has a width of 2 to 3 mm even if it is small, a high-definition LED display with a light emission interval of less than 1 mm could not be manufactured conventionally.
[0007]
On the other hand, organic EL displays and inorganic EL displays are also known as in-plane light emitting devices other than LEDs. Organic EL displays have been put to practical use for mobile phones and in-vehicles. However, since they are manufactured by a mask evaporation method, it is difficult to achieve a high definition of 40 μm or more. There is a problem that is low. Further, the inorganic EL display is a highly reliable display device and has been put to practical use for aircraft and in-vehicle use. However, the displayable color is limited due to weak B light emission, and the driving voltage is high. There is.
[0008]
The present invention has been made to solve the above problems. That is, an object of the present invention is to emit light of three primary colors of red (R), green (G), and blue (B) at a high-definition light emission interval of less than 1 mm, and to provide an arbitrary light with a high light emission intensity of each color. It is an object of the present invention to provide an LED display capable of displaying colors and having high environmental resistance and high reliability, and a method for manufacturing the same.
[0009]
[Means for Solving the Problems]
According to the present invention, an LED display is provided in which light-emitting layers (2R, 2G, 2B) that respectively emit red (R), green (G), and blue (B) are formed on the surface of the same substrate. Is provided.
[0010]
According to a preferred embodiment of the present invention, the red (R), green (G), and blue (B) light emitting layers (2R, 2G, 2B) are arranged at a fine pitch adjacent to each other. .
[0011]
According to the configuration of the present invention, since the light emitting layers (2R, 2G, 2B) that respectively emit red (R), green (G), and blue (B) are formed on the surface of the same substrate, By arranging the light emitting layers (2R, 2G, 2B) at a fine pitch adjacent to each other, light of each light emitting layer (2R, 2G, 2B) can be mixed to display an arbitrary color. it can.
By setting the pitch to less than 1 mm, light can be emitted at a high-definition light emission interval. Further, since each light emitting layer (2R, 2G, 2B) is the same as a conventional LED except that it is formed on the same substrate, the light emission intensity of each color is high, and any color can be displayed, and the resistance to light can be improved. Environmentally friendly and high reliability can be obtained.
[0012]
Further, according to the present invention, blue (B), green (G), and red (R) light-emitting regions are set at a fine pitch adjacent to each other on the surface of the same substrate, and each light-emitting layer that emits each of the colors is provided. (2R, 2G, 2B) is sequentially or simultaneously formed in the light emitting region.
[0013]
According to the method of the present invention, the blue (B), green (G), and red (R) light-emitting regions are set at a fine pitch adjacent to each other on the surface of the same substrate. By doing so, it is possible to emit light at high light emission intervals.
Further, since the respective light emitting layers (2R, 2G, 2B) for emitting the respective colors of B, G, and R are sequentially or simultaneously formed in the light emitting area, the red ( R), green (G), and blue (B) light emitting layers (2R, 2G, 2B) can be formed.
[0014]
According to a preferred embodiment of the present invention, the respective light emitting layers (2R, 2G, 2B) are formed by selective growth of a material or selective doping.
The display region and the display shape can be changed by arbitrarily setting the region where the crystal is selectively grown by the selective growth of the material.
Further, by selective doping, by selecting a doping material or changing a film forming gas concentration, an LED display capable of displaying multiple luminescent colors within the same substrate becomes possible. Furthermore, the display region and the display shape can be changed by arbitrarily setting the region to be selectively doped.
[0015]
According to a preferred embodiment of the present invention, the substrate for crystal growth (1) is maintained at a predetermined temperature in the reaction vessel (6), and the precursors of In, Ga, and N are sequentially or simultaneously supplied into the reaction vessel. , MOCVD (metal organic chemical vapor deposition) or MOMBE (metal organic molecular beam epitaxy), InGaN emitting blue (B), green (G), and red (R) is sequentially or sequentially formed on the surface of the same substrate. Grow at the same time.
[0016]
The emission color of In _y Ga _1-y N can be selected from blue (B), green (G), and red (R) by changing the mole fraction y of In in InGaN. The predetermined temperature, the precursors of In, Ga, and N and the composition thereof are selected, and InGaN emitting blue (B), green (G), and red (R) is formed on the surface of the same substrate under optimal conditions. It can be grown in a predetermined light emitting region.
[0017]
Further, the surface of the substrate is irradiated with a high-power pulsed laser, and the irradiated portion is heated at a temperature of about 400 ° C. or more and less than about 650 ° C. by changing the composition of the precursor to form blue (B) and green (G). The emitting InGaN may be grown at different locations, and then the red (R) emitting InGaN may be grown at different locations at a temperature greater than or equal to about 400 ° C. and less than about 500 ° C.
[0018]
According to this method, the precursors of In, Ga, and N are sequentially or simultaneously supplied into the reaction vessel, and the substrate surface is irradiated with the high-power pulse laser to grow InGaN on the irradiated portion. As a result, the precursor can be excited at the irradiated portion to break its molecular bond (NH bond, C-amine bond, etc.), and InGaN can be grown at that portion.
[0019]
Further, since InGaN can be grown in a minute region by irradiating a laser beam, red (R) and green (G) can be formed on the same substrate by sequentially changing the ratio of the precursors of In, Ga, and N. ) And blue (B) can be formed at a fine pitch.
[0020]
Further, at a temperature of about 400 ° C. or more and less than about 650 ° C., the composition of the precursor is changed to grow InGaN emitting blue (B) and green (G), and then red (R) at a lower temperature. Since InGaN that emits light is grown, thermal decomposition of InGaN that emits blue (B) and green (G) can be prevented.
In addition, in order to form a red LED that emits red (R), it is grown at different positions at a temperature of about 400 ° C. or more and less than about 500 ° C., so that the molar fraction y of In in InGaN is about 0.7. be increased to above, it is possible to prevent the thermal decomposition of InGaN in the process of semiconductor film of _in y _{Ga 1-y} N on the surface of the substrate grows.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, the same reference numerals are given to the common parts in the respective drawings, and the duplicate description will be omitted.
[0022]
FIG. 1 is a configuration diagram of an LED display according to the present invention. As shown in this figure, the LED display according to the present invention has light emitting layers 2R, 2G, and 2B that respectively emit red (R), green (G), and blue (B) formed on the surface of the same substrate 1. is there. The red (R), green (G), and blue (B) light emitting layers 2R, 2G, and 2B are arranged at a fine pitch adjacent to each other. This interval is a fine (fine) pitch of less than 1 mm, and preferably a pitch of less than 0.1 mm (100 μm).
[0023]
FIG. 2 is a configuration diagram of a main part of FIG. Each light emitting layer 2R, 2G, 2B in this example is an LED having an InGaN / InGaN double hetero structure. As shown in this figure, each light emitting layer 2R, 2G, 2B is made of a mixed crystal of (Al, Ga, In) N. Each light-emitting layer 2R, 2G, 2B is, InGaN (precisely the _In y _{Ga 1-y} N) by adjusting the mole fraction y of In, red (R), green (G), and blue (B) Are emitted.
[0024]
Note that the present invention is not limited to the configurations illustrated in FIGS. 1 and 2, and the respective light emitting layers 2R, 2G, and 2B that emit red (R), green (G), and blue (B) respectively on the surface of the same substrate. May be different in configuration as long as they are arranged at a fine pitch adjacent to each other.
[0025]
According to the configuration of the present invention described above, the light-emitting layers 2R, 2G, and 2B that emit red (R), green (G), and blue (B), respectively, are arranged adjacent to each other at a fine pitch on the surface of the same substrate. The light from the respective light emitting layers 2R, 2G, and 2B can be mixed to emit an arbitrary color at a high-definition light emission interval. Furthermore, since each light emitting layer 2R, 2G, 2B is the same as the conventional LED except that it is formed on the same substrate, the light emission intensity of each color is high and any color can be displayed, and environmental resistance is high. And high reliability can be obtained.
[0026]
Next, a method for manufacturing the LED display of the present invention will be described.
According to the method of the present invention, blue (B), green (G), and red (R) light-emitting areas are set at a fine pitch adjacent to each other on the surface of the same substrate 1, and a light-emitting layer that emits each of the colors is provided. 2R, 2G, and 2B are sequentially or simultaneously formed in each light emitting region. That is, an LED display is manufactured by selectively forming a material capable of emitting LED light in a desired region in the same substrate.
[0027]
The formation of each of the light emitting layers 2R, 2G, and 2B is preferably performed by selective growth of a material or selective doping.
[0028]
As a means for selectively growing the light emitting layers 2R, 2G, and 2B, a method of controlling the composition of a mixed crystal material such as InGaN can be applied. In other words, the band gap changes by changing the composition for crystal growth for each selected region, thereby changing the emission color.
[0029]
As means for changing the composition grown for each desired region, switching of the reaction gas and control of the concentration while using local heating, selective light irradiation, or the like, means using a metal thin film patterned by photolithography, and the like can be applied.
[0030]
The display region and the display shape can be changed by arbitrarily setting the region where the crystal is selectively grown by the selective growth of the material described above.
[0031]
As a means for selectively doping each of the light emitting layers 2R, 2G, and 2B, a means for forming a specific level by ion doping a material having a wide band gap such as GaN, for example, can be applied. That is, by changing the ion species to be doped for each selected region, the formed level changes, thereby changing the emission color.
[0032]
Scanning of an ion beam, scanning of a substrate, patterning by photolithography, or the like can be applied to the means for doping a desired region.
[0033]
By the above-described selective doping, by selecting a doping material or changing a film forming gas concentration, it becomes possible to provide an LED display capable of displaying multiple luminescent colors within the same substrate. Furthermore, the display region and the display shape can be changed by arbitrarily setting the region to be selectively doped.
[0034]
【Example】
FIG. 3 is a schematic view of an apparatus for manufacturing an LED display according to the present invention. In this figure, a laser beam 10 is generated and emitted by a laser 14a (for example, an excimer laser) controlled by a laser controller 12. The laser beam 10 passes through the optical system 14b and the beam homogenizer 14c, is reflected downward by the mirror 14d, and is irradiated on the upper surface of the substrate 1 through an opening (not shown) provided in the reaction vessel 6. Substrate 1 may be silicon, SiC or sapphire.
[0035]
The laser beam 10 scans the substrate by swinging the mirror 14d or moving the optical system 14b. The stage controller 16 can move the substrate 1 two-dimensionally. Further, the inside of the reaction vessel 6 (chamber) is controlled to a predetermined gas atmosphere by a pump system 15 and a gas introduction unit 17.
[0036]
FIG. 4 is a configuration diagram of a main part of FIG. In this figure, the substrate 1 is maintained in a reaction vessel 6 at a temperature at which InGaN is not thermally decomposed by temperature control means (for example, a heater) not shown. Further, precursors of In, Ga, and N are supplied into the reaction vessel 6 sequentially or simultaneously from the gas introduction unit 17. The temperature at which InGaN does not thermally decompose may be about 400 ° C. or more and less than about 650 ° C. If the temperature is lower than about 400 ° C., it is difficult to form an InGaN crystal.
[0037]
Using the above-described apparatus, the substrate 1 made of silicon or sapphire is maintained at a predetermined temperature in the reaction vessel 6, and In, Ga, and N precursors are sequentially or simultaneously supplied into the reaction vessel, and MOCVD (organic metal vapor) is performed. InGaN that emits blue (B), green (G), and red (R) is sequentially or simultaneously grown on the surface of the same substrate by a phase growth method) or MOMBE (organic metal molecular beam epitaxy method).
[0038]
The substrate surface is irradiated with a high-power pulsed laser, and the irradiated portion emits blue (B) and green (G) light at a temperature of about 400 ° C. or more and less than about 650 ° C. by changing the composition of the precursor. InGaN is grown at different locations, and then, at temperatures above about 400 ° C. and less than about 500 ° C., InGaN emitting red (R) is grown at different locations.
[0039]
For example, TMG (trimethylgallium) is used as a Ga precursor, TMI (trimethylindium) is used as an In precursor, and ammonia, N ₂ H ₂ (hydrazine) and TMNH ₂ (trimethylamine) are used as N precursors. .
[0040]
Note the composition of these precursors, it is preferable vary depending on the mole fraction y of In of interest in growing In y _Ga 1-y _N. For example, to increase the molar fraction y of In, the molar ratio of the In precursor is increased.
[0041]
For example, by using an excimer laser having a wavelength of 277 nm or less as a high-power pulse laser, various precursors including ammonia can be excited and decomposed by the same pulse laser to grow InGaN. Note that an excimer laser or a YAG laser having a wavelength of 277 nm or more may be used. In the case of a YAG laser, a wavelength of 532 nm, 355 nm, or 266 nm can be used.
[0042]
MOCVD (metal-organic chemical vapor deposition) or MOMBE (metal-organic molecular beam epitaxy) is applied as a method of irradiating the surface of the substrate 1 with a high-power pulse laser and growing InGaN on the irradiated portion.
[0043]
According to the method described above, the emission color of In _y Ga _1-y N can be selected from blue (B), green (G), and red (R) by changing the molar fraction y of In in InGaN. Therefore, a predetermined temperature suitable for each emission color, a precursor of In, Ga, and N and a composition thereof are selected, and blue (B), green (G), and red ( InGaN emitting R) can be grown in a predetermined light emitting region.
[0044]
In addition, precursors of In, Ga, and N are sequentially or simultaneously supplied into the reaction vessel, and the substrate surface is irradiated with a high-power pulse laser to grow InGaN on the irradiated portion. The molecular bond (NH bond, C-amine bond, etc.) can be cut off by excitation at the irradiated portion, and InGaN can be grown on that portion.
[0045]
Further, since InGaN can be grown in a minute region by irradiating a laser beam, red (R) and green (G) can be formed on the same substrate by sequentially changing the ratio of the precursors of In, Ga, and N. ) And blue (B) can be formed at a fine pitch.
[0046]
Further, at a temperature of about 400 ° C. or more and less than about 650 ° C., the composition of the precursor is changed to grow InGaN emitting blue (B) and green (G), and then red (R) at a lower temperature. Since InGaN that emits light is grown, thermal decomposition of InGaN that emits blue (B) and green (G) can be prevented.
In addition, in order to form a red LED that emits red (R), it is grown at different positions at a temperature of about 400 ° C. or more and less than about 500 ° C., so that the molar fraction y of In in InGaN is about 0.7. be increased to above, it is possible to prevent the thermal decomposition of InGaN in the process of semiconductor film of _in y _{Ga 1-y} N on the surface of the substrate grows.
[0047]
It should be noted that the present invention is not limited to the above-described examples and embodiments, and it is needless to say that various changes can be made without departing from the gist of the present invention.
[0048]
【The invention's effect】
As described above, according to the LED display and the method of manufacturing the same of the present invention, it is possible to emit red (R), green (G), and blue (B) three primary colors at a high-definition emission interval of less than 1 mm. In addition, it has excellent effects such as high emission intensity of each color, display of any color, and environmental resistance and high reliability.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an LED display according to the present invention.
FIG. 2 is a configuration diagram of a main part of FIG. 1;
FIG. 3 is a schematic view of an apparatus for manufacturing an LED display according to the present invention.
FIG. 4 is a configuration diagram of a main part of FIG. 3;
FIG. 5 is a schematic view of a conventional 3-in-1 full-color LED.
FIG. 6 is a schematic perspective view of an LED display using a 3-in-1 full-color LED.
[Explanation of symbols]
1 substrate, 2R, 2G, 2B light emitting layer,
6 reaction vessel, 7 heater, 8 exhaust port, 9 radiation thermometer, 10 laser beam, 12 laser controller,
14a excimer laser, 14b optical system,
14c beam homogenizer, 14d mirror,
15 pump system, 16 stage controller,
17 Gas introduction section

Claims (6)

An LED display, wherein light-emitting layers (2R, 2G, 2B) that respectively emit red (R), green (G), and blue (B) are formed on a surface of the same substrate. 2. The device according to claim 1, wherein the red (R), green (G), and blue (B) light emitting layers (2R, 2G, 2B) are arranged at a fine pitch adjacent to each other. The LED display as described. Blue (B), green (G), and red (R) light-emitting areas are set at a fine pitch adjacent to each other on the surface of the same substrate, and the light-emitting layers (2R, 2G, 2B) that emit light of the respective colors are formed. A method for manufacturing an LED display, wherein the LED display is formed sequentially or simultaneously in a light emitting region. The method for manufacturing an LED display according to claim 3, wherein the light emitting layers (2R, 2G, 2B) are formed by selective growth or selective doping of a material. The substrate for crystal growth (1) is maintained at a predetermined temperature in the reaction vessel (6), and precursors of In, Ga, and N are sequentially or simultaneously supplied into the reaction vessel, and MOCVD (metal organic chemical vapor deposition) is performed. Alternatively, InGaN emitting blue (B), green (G), and red (R) is sequentially or simultaneously grown on the surface of the same substrate by MOMBE (organic metal molecular beam epitaxy method). Item 4. The method for manufacturing an LED display according to Item 3. The substrate surface is irradiated with a high-power pulse laser, and the irradiated portion emits blue (B) and green (G) light at a temperature of about 400 ° C. or more and less than about 650 ° C. by changing the composition of the precursor. The LED of claim 5, wherein the InGaN is grown at different locations, and then the red (R) emitting InGaN is grown at different locations at a temperature of about 400C or more and less than about 500C. Display manufacturing method.

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