JPH11251634A - Led element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface light emitting type LED element capable of heightening emitted light per unit area. SOLUTION: An LED element is composed of light emitting layers 2 formed on one main surface 11 of a silicon substrate 1 for emitting the light to the surface 11 side, thin filmy transparent electrodes 3 lamination-formed on the light emitting layers 2, a latticed electrode 4 provided with metallic lattices 41 lamination-formed on the transparent electrodes 3 for enveloping multiple aperture parts 42 as well as an opposite electrode 5 formed on another main surface 12 for opposing the latticed electrode 4. In such a constitution, the interlattice intervals can be widened without decreasing the light emitting efficiency of the light emitting layers 2 in the central parts of respective metallic lattices 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-emitting type LED device in which a light-emitting layer is formed on one surface of a silicon substrate.

[0002]

2. Description of the Related Art Conventionally, as this kind of LED element, there is an LED element having a configuration shown in FIG. A light emitting layer A is formed on one surface of a silicon substrate A1 via a buffer layer A2 and emits emitted light to one surface side, and a grating laminated on the light emitting layer A and surrounding a plurality of openings B1. Grid electrode B provided with B2
And a grid electrode B formed on the other surface of the silicon substrate A1.
And a facing electrode C facing the front side.

More specifically, the emitted light emitted from the light emitting layer A is emitted from the plurality of openings B1 surrounded by the lattice B2 to the one surface side of the silicon substrate A1 in a planar manner. The silicon substrate A1 has a side of 5 mm or more, and the grid electrode B has a grid B2 such that the opening B1 is formed in a square shape and the side is formed in a range of 0.2 mm to 1.0 mm.
Are formed at a predetermined interstitial space.

[0004]

The above-mentioned conventional LED
In the device, the emission light emitted from the light emitting layer A is transmitted to a plurality of openings B.
By emitting the light from the surface in a planar manner, a thin surface emitting element can be obtained.

However, the emitted light emitted from the light emitting layer A is shielded by the grid B2 of the grid electrode B and is emitted only from the opening B1 because the grid B2 of the grid electrode B is not transparent. The defined light emission efficiency is degraded. Also, if the interstitial spacing of the lattices B2 is increased to improve the light emission efficiency, the light emission efficiency of the light emitting layer A at the center of each lattice B2 decreases, and the light emission efficiency similarly deteriorates.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a surface-emitting type LED device capable of increasing the amount of emitted light per unit area.

[0007]

According to a first aspect of the present invention, there is provided a light emitting layer which is formed on one surface of a silicon substrate and emits emitted light to one surface side, and is laminated on the light emitting layer. A transparent electrode in the form of a thin film formed, a grid electrode provided with a metal grid laminated around the transparent electrode and surrounding a plurality of openings, and formed on the other surface of the silicon substrate and facing the grid electrode. And a facing electrode.

According to a second aspect of the present invention, in the first aspect, the transparent electrode is made of indium oxide.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.

Reference numeral 1 denotes a silicon substrate, one surface 11 and the other surface 1
2, having a thickness of 0.3 mm to 0.8 mm, a side of about 10 mm, and having conductivity.
Excellent strength and heat dissipation.

Reference numeral 2 denotes a light emitting layer, which is p-type GaAs of the first conductivity type.
The p-type GaAlAs layer 21 and the n-type GaAlAs layer 22 are formed by sequentially laminating the p-type GaAlAs layer 21 and the n-type GaAlAs layer 22 on the one surface 11 of the silicon substrate 1. . Here, n-type GaAlA
The s layer 22 is formed in a thin film shape, and emitted light emitted at the interface between the two layers is transmitted to the one surface 11 side of the silicon substrate 1 through the n-type GaAlAs layer 22.

Reference numeral 3 denotes a transparent electrode, which is made of indium oxide having conductivity, has transparency, and is formed in a thin film on the light emitting layer 2 without blocking emission light emitted by the light emitting layer 2. It is released to the one surface 11 side of the silicon substrate 1.

Reference numeral 4 denotes a grid-like electrode, which is formed of metal in a thin plate shape and has better electric conductivity than that of the transparent electrode 3. A metal grid 41 formed in a grid shape is provided, and A plurality of openings 42 are formed, and are laminated so as to surround the openings 42 and contact the transparent electrode 3. Here, the metal grids 41 are formed so as to form an inter-grating interval of about 2 mm. A facing electrode 5 is formed on the other surface 12 of the silicon substrate 1 and faces the grid electrode 4.

The operation of this will be described. When a current is applied from the facing electrode 5 to the grid electrode 4, the light emitting layer 2 emits emitted light to the one surface 11 side of the silicon substrate 1. The emitted light is emitted without being shielded because the transparent electrode 3 is transparent, and the interstitial space of the metal grid 41 is about 2 mm, which is wider than the conventional one. The light emission efficiency, which is defined by the amount of emitted light per unit area, is reduced.

Further, since the transparent electrode 3 having conductivity is laminated on the light emitting layer 2, the luminous efficiency of the light emitting layer 2 at the central portion of each metal grid 41 is reduced even if the space between the lattices is widened. Nothing to do. Therefore, the emitted light is emitted from the plurality of openings 42 in a state where the amount of light is large.

Since the grid electrode 4 has a good electrical conductivity of the metal grid 41 as compared with the transparent electrode 3, even if a large current flows between the facing electrodes 5, the calorific value is small, and the emitted light is small. By flowing a large current, the light is emitted from the opening 42 in a state where the light amount is further increased.

In the LED element of this embodiment, as described above, the transparent electrode 3 is formed on the light emitting layer 2 and the grid electrode 4 is formed on the transparent electrode 3 to form a plurality of openings. Since the metal grids 41 surrounding the portion 42 are provided, the interval between the grids can be widened to increase the emission light per unit area without reducing the luminous efficiency of the light emitting layer 2 at the center of each metal grid 41. , Metal grid 4
1 has a better electrical conductivity than the transparent electrode 3,
Since the calorific value of the metal grid 41 is small, a large current can flow between the grid electrode 4 and the facing electrode 5 to emit a large amount of emitted light from the opening 42.

Further, since the transparent electrode 3 is made of indium oxide, it is easy to form a film and inexpensive indium oxide is used.
The thin-film transparent electrode 3 can be easily formed on the light emitting layer 2.

In this embodiment, the light emitting layer 2 is formed to have the first conductivity type of p-type and the second conductivity type of n-type. However, the first conductivity type is n-type and the second conductivity type is n-type. May be formed in a p-type and is not limited.

[0020]

According to the first aspect of the present invention, the transparent electrode is formed on the light emitting layer and the grid electrode is formed on the transparent electrode, and the metal grid surrounding the plurality of openings is provided. Without reducing the luminous efficiency of the light emitting layer at the center of the metal grid, the spacing between the metal grids can be widened to increase the emission light per unit area, and the electrical conductivity of the metal grid is better than that of the transparent electrode Since the calorific value of the metal grid is small, a large current can be passed between the grid electrode and the facing electrode, and a large amount of emitted light can be emitted from the opening.

According to the second aspect, in addition to the effect of the first aspect, since the transparent electrode is made of indium oxide, the thin film-shaped transparent electrode emits light by using inexpensive indium oxide which is easy to form a film. It can be easily formed into layers.

[Brief description of the drawings]

FIG. 1 is a conceptual perspective view showing an embodiment of the present invention.

FIG. 2 is a conceptual perspective view showing a conventional example.

[Explanation of symbols]

 Reference Signs List 1 silicon substrate 11 one surface 12 other surface 2 light emitting layer 3 transparent electrode 4 grid electrode 41 metal grid 42 opening 5 facing electrode

Claims (2)

[Claims] 1. A light emitting layer formed on one surface of a silicon substrate and emitting emitted light to one surface side, a thin-film transparent electrode laminated on the light emitting layer, and a plurality of openings laminated on the transparent electrode. A grid electrode provided with a metal grid surrounding
An LED element comprising: a facing electrode formed on the other surface of the silicon substrate and facing the grid electrode. 2. The LED device according to claim 1, wherein said transparent electrode is made of indium oxide.