JPH10256604A - Semiconductor light emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor light emitting element for display in which the quality of color tone representation can be enhanced at the time of multicolor display or full-color display while reducing the size of the unit. SOLUTION: At least two types of light emitting element chip emitting light of different wavelength are formed in triangular shape and arranged such that the vertexes of triangular light emitting element chips are brought close to each other. For example, red, blue and green LED chips 1, 2 and 3 are formed into rectangular equilateral triangles or regular triangles and arranged such that the right angle or one vertexes are collected at one point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light emitting device having a plurality of light emitting device chips and capable of emitting light of a mixed color. More specifically, one of a plurality of chips
The present invention relates to a semiconductor light-emitting element that can be used for a color display screen that is small in size and does not cause any discomfort even if one pixel of the screen is formed.

[0002]

2. Description of the Related Art Conventionally, a light emitting element chip (hereinafter, referred to as an LED chip) of a semiconductor light emitting element is, for example, an LED chip which emits green light, as shown in FIG.
A p-type GaP layer 12 is epitaxially grown on an n-type GaP substrate 11 to form a pn junction. A p-side electrode 13 is provided on the front side of the stacked semiconductor layers, and an n-side electrode 14 is provided on the back side of the substrate. A structure is used. Also,
The LED chip that emits red light also has AlG on the GaAs substrate.
It is formed by stacking an aAs-based or AlGaInP-based compound semiconductor layer.

[0003] Further, for example, a structure in which a gallium nitride compound semiconductor layer is laminated on an insulating substrate made of sapphire or the like, such as a blue semiconductor light emitting device, is shown in FIG. As shown in a schematic diagram of an example of the chip, the chip is formed by providing both a p-side electrode 28 and an n-side electrode 29 on the surface side.
This structure has an n-type layer (cladding layer) 23 in which, for example, n-type GaN is epitaxially grown on a sapphire substrate 21, and a material whose band gap energy is smaller than that of the cladding layer, for example, InG.
an active layer 24 made of an aN-based (which means that the ratio of In to Ga can vary, the same applies hereinafter) compound semiconductor;
A p-type layer (cladding layer) 25 made of p-type GaN is laminated, and the p-side electrode 28 is electrically connected to the p-type layer 25 on the surface thereof, and a part of the laminated semiconductor layer is etched. And electrically connected to the exposed n-type layer 23, the n-side electrode 2
The LED chip is formed by providing the LED chip 9.

Each of these LED chips is formed into a chip by cleavage or break so that the planar shape becomes substantially square. When used in a display device or the like, the square LED chips are arranged in a matrix, and desired characters and images are displayed by turning on and off the respective LED chips.

[0005]

When a display device is configured by arranging the above-described LED chips, a single-color display can be configured by arranging the LED chips in a matrix as it is. In this case, it is necessary to form one pixel with two or more types of chips, and a wasteful area is generated when two or more square chips are arranged to form one pixel, or light on a distant side is insufficient. , And a small pixel cannot be formed. Therefore, there are problems that a delicate display device cannot be formed, color tone expression becomes low quality, and a hindrance to downsizing of a unit of the display device occurs.

The present invention has been made in order to solve such a problem, and a display device capable of improving the quality of color tone expression and reducing the size of a unit when performing multi-color display or full-color display. It is an object to provide a semiconductor light-emitting device for use in a semiconductor device.

Another object of the present invention is to provide a combination of chips capable of performing uniform color display even when color display is performed by a combination of semiconductor light emitting element chips.

[0008]

A semiconductor light emitting device according to the present invention has at least two types of light emitting device chips for emitting light of different wavelengths each formed in a triangular shape, and the triangular light emitting device has a planar shape. The light emitting element chips are arranged such that the vertices of the chips are close to each other. With such a structure, even light emitting element chips of three colors can be arranged without gaps, and one pixel with a small area and excellent in color tone expression can be formed.

If the light emitting element chips are three kinds of light emitting element chips that emit red, green and blue light, full color light emission can be achieved. Further, as a specific structure of the arrangement of the above-mentioned triangular chips, there are a right triangle, a structure in which four light emitting element chips are arranged with the right corner as a vertex, or a regular triangle, in which six light emitting element chips are arranged. By adopting a structure in which the light emitting element chips of three colors are arranged, the light emitting element chips of three colors can be arranged in close proximity to each other, and the outer shape of the set can be a square or hexagonal pixel. A display screen can be formed.

[0010] Of the three types of light emitting element chips, by arranging the number of green light emitting element chips larger than the number of red light emitting element chips, it is possible to increase the intensity of green with low luminance, and to obtain uniform light as a whole. Easy to get full color.

[0011]

Next, a semiconductor light emitting device of the present invention will be described with reference to the drawings. In the light emitting device of the present invention, for example, as shown in a plan view of one embodiment of the present invention in FIG. 1, each LED chip is formed in a triangular shape, and the vertex thereof is at one point when viewed in plan. It is characterized by being arranged to gather.

In the example shown in FIG. 1, a red LED chip 1, a green LED chip 2, and a blue LED chip 3 are each formed in a right-angled isosceles triangular shape, and the right-angled corner is defined as a vertex. By arranging the vertices at one point in a plane shape, one of the full-color display devices is provided.
A pixel. Since the LED chips are arranged so as to gather at one point with the right-angled corners as vertices, the four LED chips are arranged, so that the LED chips are buried closely around one point without any gap, and the overall shape is square. Are formed.

In the example shown in FIG. 1, of the four LED chips, two green LED chips 2 are arranged. This is because the luminance of the green LED chip 2 is often low. By arranging a large number of LED chips having a low luminance (large area), the luminance of each color is maintained in a balance, and the colors are mixed to form a full color. When displaying, it is easy to perform color display with excellent color tone. Therefore, when the brightness of the blue LED chip 3 is lower, or when the blue LED chip 3 is
Two chips 2 can be used.

Each LED chip has a double hetero junction structure in which an active layer is sandwiched between a p-type layer and an n-type layer, or a p-type layer and an n-type layer, as described above. Are laminated so as to form a pn junction structure in which
Electrodes are formed so as to be connected to the n-type layer and the p-type layer, respectively, and cut and separated from the wafer by dicing or the like. At the time of this cutting and separating, the electrodes are cut so as to form a right-angled triangular shape, and the electrodes are formed such that an electrode is provided for each right-angled triangular chip. The red and green LED chips 1 and 2 are made of GaAs
Since a substrate or a GaP substrate is used, one electrode is provided on the back surface of the substrate, and only the other electrodes 11 and 21 are shown in FIG.
As shown in the figure, the base is formed on the bottom side of the center of the triangle. Since the blue LED chip 3 uses an insulating substrate such as sapphire, the p-side electrode 31 and n
Both of the side electrodes 32 are provided on the front side.

According to the present invention, light emitting element chips of two or more colors are formed in a triangular shape, and one pixel is formed by arranging the vertices so as to gather at one point. The chips are arranged close to each other without wasteful space. As a result, when displaying in color,
A color display with excellent color tone can be obtained by sufficiently mixing colors. Moreover, since each LED chip constitutes one pixel in close proximity, the pixel can be made smaller, a delicate image can be displayed with fine pixels, and a display device with excellent display quality can be provided. Can be.

FIG. 2 is an explanatory plan view showing a modification of the semiconductor light emitting device of the present invention. The example shown in FIG. 2 is a light emitting element in which three color LED chips of a red LED chip 1, a green LED chip 2, and a blue LED chip 3 are arranged to display a full color similarly to FIG. Are shown. In this example, each LED chip is formed not as a right-angled isosceles triangle but as a regular triangle, and the vertexes are arranged so as to be concentrated at one point.
As a result, the outer shape is formed in a pixel having a hexagonal shape by making just one round with the six LED chips. In the example shown in FIG. 2, one red LED chip 1, three green LED chips 2, and two blue LED chips 3, a total of six L LEDs
One pixel is formed by the ED chip. The reason for making the numbers different is that, as described above, when the brightness differs depending on the LED chip, the brightness of each color becomes uniform as a whole of one pixel.
If the luminance of the ED chip is the same, it is of course formed by arranging two LED chips. Each of the red LED chip 1 and the blue LED chip 3 is formed one by one to form a green LE.
Other combinations such as four D chips 2 may be used.

With this combination, the LED chips of each color can be dispersed and arranged within one pixel, and light of a more uniform color can be emitted.
Moreover, the number of LED chips is not extremely large.
Also in the case of manufacturing an ED chip, there is an advantage that cleavage is easy when the direction is 60 ° and the manufacture is easy. Also, the outer shape of the combination is a regular hexagon, which is convenient for arranging the display screen in a matrix.

In each of the above examples, the shape of the LED chip is a right-angled isosceles triangle or a regular triangle. However, with such a shape, a plurality of LED chips are arranged and one LED chip is formed. When a pixel is formed, its outer shape becomes a square or a regular hexagon, and when these are further arranged in a matrix to form a display screen, they can be regularly arranged and a beautiful display screen can be obtained. The shape of the chip is not limited to these shapes. In other words, even in other shapes, if the shape is triangular, the vertices can be arranged around the center. Further, even if all the LED chips do not have the same shape, it is also possible to adjust the difference in luminance depending on the color by using different areas. That is, by increasing the area of the LED chips of a color having a small luminance, the number can be all the same.

Further, in the examples shown in FIGS. 1 and 2, plan views are shown, but the height of the light emitting portion of each color LED chip from the substrate can be changed. That is, in relation to the wavelength of each color, light having a shorter wavelength is easily absorbed by a semiconductor having a band gap energy that emits light having a longer wavelength. Therefore, by arranging a portion that emits light with a short wavelength on the light emitting surface side and disposing an LED chip that emits a long wavelength light at a lower position, the light emitted on the light extraction surface side is absorbed. It is used without any trouble, and the intensity of light does not change.

[0020]

According to the present invention, the LED chips are arranged in a triangular shape so that their vertices are centered, so that LED chips of different colors can be brought close to each other. As a result, the colors to be mixed become beautiful, the color tone expression is improved, and the distance between each pixel is reduced,
A delicate display screen can be formed. Moreover, each L
Since the ED chips are provided close to each other, the size of the display screen can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory plan view of one embodiment of a semiconductor light emitting device of the present invention.

FIG. 2 is an explanatory plan view showing a modified example of the semiconductor light emitting device of FIG. 1;

FIG. 3 is a perspective view illustrating an example of a conventional semiconductor light emitting device.

[Explanation of symbols]

 1 red LED chip 2 green LED chip 3 blue LED chip

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masayuki Sonobe 21st Ryoin Mizozakicho, Ukyo-ku, Kyoto City (72) Inventor Noriwa Ito 21st Rohm Co., Ltd., Saiin-Mizozakicho, Ukyo-ku, Kyoto

Claims (5)

[Claims] At least two light emitting light of different wavelengths
Each kind of light emitting element chip is formed in a triangular shape,
A light-emitting element in which the light-emitting element chips are arranged such that the vertices of the triangular light-emitting element chips in a planar shape are close to each other. 2. The semiconductor light emitting device according to claim 1, wherein said light emitting device chip comprises three types of light emitting device chips that emit red, green, and blue light, respectively, and can emit full color light. 3. The semiconductor light emitting device according to claim 2, wherein, among the three types of light emitting device chips, the area of the green light emitting device chip is arranged to be larger than the area of the red light emitting device chip. 4. The semiconductor light emitting device according to claim 1, wherein the shape of the light emitting device chip is a right triangle, and four light emitting device chips are arranged with a right angle as a vertex. 5. The semiconductor light emitting device according to claim 1, wherein said light emitting device chip has a regular triangular shape and six light emitting device chips are arranged.