CN108336204B - LED chip with single-sided light emitting function and manufacturing method thereof - Google Patents

Abstract

The invention relates to a single-sided light emitting LED chip and a manufacturing method thereof, comprising a substrate; the light-emitting layer is connected to the upper surface of the substrate, a side light-blocking layer is covered on the side surface of the light-emitting layer, a groove is formed on the upper surface of the light-emitting layer, close to the edge, and a light-blocking material is filled in the groove; and an electrode electrically connected to the light emitting layer. The beneficial effects of the invention are as follows: the side of the light-emitting layer is coated with the side light-blocking layer to form a first light-blocking structure, and the groove of the light-emitting layer close to the edge is filled with a light-blocking material to form a second light-blocking structure, so that light leakage from the side of the light-emitting layer is completely blocked, the light-emitting layer is ensured to emit light only from the upper surface, and the requirements of the high-precision light source of the optical encoder are met.

Description

LED chip with single-side light emission and manufacturing method thereof

Technical Field

The invention relates to the technical field of LED chips, and in particular to a single-side light-emitting LED chip and a manufacturing method thereof.

Background technique

At present, LED chips are widely used in the field of optical encoders. As optical encoders pursue higher and higher precision, people's demand for high-precision light sources used in optical encoders is also increasing.

As shown in FIG1 , an existing LED chip includes a substrate 91, a reflective layer 92 disposed on the substrate, a light-emitting layer 93 disposed on the reflective layer, and an electrode 94 electrically connected to the light-emitting layer 93. Under the action of the electrode 94, the light-emitting layer 93 generates light, and under the action of the reflective layer 92, the light is diffused toward the top and around the light-emitting layer 93.

However, the high-precision light source used in optical encoders requires that the LED chip emit light only from the top surface. Existing LED chips obviously cannot meet the requirements of high-precision light sources.

Summary of the invention

The purpose of the present invention is to overcome the defects of the prior art and provide a single-sided light emitting LED chip and a manufacturing method thereof, which can solve the problem that the existing LED chips cannot meet the requirements of high-precision light sources.

The technical solution to achieve the above purpose is:

The present invention provides a single-side light emitting LED chip, comprising:

a substrate;

a reflective layer disposed on the upper surface of the substrate;

A light-emitting layer is disposed on the upper surface of the reflective layer, the side of the light-emitting layer is covered with a side light-blocking layer, and a groove is formed on the upper surface of the light-emitting layer near the edge, and the groove is filled with a light-blocking material; and

An electrode electrically connected to the light emitting layer.

The beneficial effect of the present invention is that a first light-blocking structure is formed by coating a side light-blocking layer on the side of the light-emitting layer, and a second light-blocking structure is formed by filling a light-blocking material in a groove near the edge of the light-emitting layer, thereby completely blocking light from leaking from the side of the light-emitting layer and ensuring that the light-emitting layer only emits light from the upper surface, which meets the requirements of high-precision light sources for optical encoders.

A further improvement of the LED chip with single-side light emission of the present invention is that the side surface of the light-emitting layer is an inclined surface.

A further improvement of the LED chip with single-side light emission of the present invention is that the inclined surface is a circular arc-shaped concave surface.

A further improvement of the LED chip with single-side light emission of the present invention is that the side light blocking layer is a light absorbing layer, and the light blocking material is a light absorbing material.

A further improvement of the LED chip with single-side light emission of the present invention is that the side light blocking layer is a metal reflective layer, and the light blocking material is a metal reflective material.

A further improvement of the LED chip with single-side light emission of the present invention is that the bottom of the groove is located at the bottom of the light-emitting layer.

A further improvement of the single-sided light-emitting LED chip of the present invention is that an upper light-blocking layer is coated on the surface of the upper surface of the light-emitting layer between the groove and the edge of the light-emitting layer, one side of the upper light-blocking layer is connected to the side light-blocking layer, and the other side of the upper light-blocking layer is connected to the light-blocking material.

The present invention also provides a method for manufacturing a single-side light emitting LED chip, comprising:

providing a substrate;

A light-emitting layer is arranged on the substrate, and a side light-blocking layer is coated on the side of the light-emitting layer;

Processing a groove near the edge of the upper surface of the light-emitting layer, and filling the groove with a light-blocking material;

An electrode is provided to electrically connect the electrode to the light emitting layer.

A further improvement of the method for manufacturing a single-side light emitting LED chip of the present invention is that it further comprises:

The side surface of the light emitting layer is processed to be inclined inward to form an inclined surface.

A further improvement of the method for manufacturing a single-side light emitting LED chip of the present invention is that it further comprises:

A light absorbing layer is selected as the side light blocking layer; and a light absorbing material is selected as the light blocking material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing the structure of an existing LED chip.

FIG. 2 is a schematic diagram of a single-side light-emitting LED chip of the present invention with the light-shielding structure omitted.

FIG. 3 is a schematic diagram of the structure of a single-side light-emitting LED chip of the present invention.

FIG. 4 is a top view of a single-side light emitting LED chip according to the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Referring to FIG3 , the present invention provides a single-sided light emitting LED chip and a manufacturing method thereof, wherein the light emitting layer emits light only from the upper portion, which meets the requirements of the optical encoder for a high-precision light source and solves the problem that the existing LED chip cannot meet the requirements for a high-precision light source. The single-sided light emitting LED chip of the present invention is described below in conjunction with the accompanying drawings.

As shown in Figures 2 to 4, the single-sided LED chip of the present invention includes a substrate 11, a DBR reflective layer 12 arranged on the upper surface of the substrate, a light-emitting layer 13 arranged on the upper surface of the DBR reflective layer, and an electrode 14 arranged on the light-emitting layer and electrically connected to the light-emitting layer.

The substrate 11 is a GaAs substrate. The light emitting layer 13 includes an N-type semiconductor layer, an intrinsic semiconductor layer located on the N-type semiconductor layer, and a P-type semiconductor layer located on the intrinsic semiconductor layer, and the materials of the three are all GaAlAs.

The side of the light-emitting layer 13 is covered with a side light-blocking layer 21, thereby preventing light leakage from the side of the light-emitting layer 13, forming a first light-blocking structure. Preferably, the side of the light-emitting layer 13 is inclined inward to form an inclined surface 131, and further, the inclined surface 131 is a circular arc-shaped concave surface. By designing the side surface as an inclined surface, especially a circular arc-shaped concave surface, the possibility of total internal reflection of light can be increased, and the area of the side light-blocking layer 21 can be increased, so as to better block the light emitted from the side and prevent light from leaking from the side.

A groove 132 is formed near the edge of the upper surface of the light-emitting layer 13, and the groove 132 is filled with a light-blocking material 22. The groove 132 and the light-blocking material 22 form a second light-blocking structure to prevent light from being transmitted laterally to the side. Preferably, the bottom of the groove 132 is located at the bottom of the light-emitting layer 13, so that the light-emitting layer 13 at this location is completely blocked by the groove 132, and the light-blocking material 22 completely blocks the propagation of light in the lateral direction. The side wall 133 of the groove is an arc surface, which increases the contact area between the light-blocking material 22 and the side wall 133 of the groove.

The upper surface of the light-emitting layer 13 between the groove 132 and the edge of the light-emitting layer is a light-shielding surface 135, and the remaining surface is a light-emitting surface 134. The light-shielding surface 135 is coated with an upper light-blocking layer 23, one side of which is connected to the side light-blocking layer 21, and the other side is connected to the light-blocking material 22. The upper light-blocking layer 23 blocks the light from the light-shielding surface 135, so that the amount of light leaking from the side is reduced to a minimum, and the light is emitted only from the continuous light-emitting surface 134.

In a preferred embodiment, the side light blocking layer 21 and the upper light blocking layer 23 are metal reflective layers, and the light blocking material 22 is a metal reflective material, so that the light propagating laterally in the light emitting layer 13 is reflected back to the light emitting layer 13 through the metal reflective layer and cannot leak out from the side.

In another preferred embodiment, the side light blocking layer 21 and the upper light blocking layer 23 are light absorbing layers, and the light blocking material 22 is a light absorbing material. The light propagating laterally in the light emitting layer 13 is absorbed by the light absorbing layer and cannot leak out from the side. When the light absorbing layer and the light absorbing material are used, the light emitted from the light emitting surface 134 can be further emitted vertically without any reflection due to the complete absorption of the light propagating laterally in the light emitting layer 13, thereby obtaining a better light distribution curve.

The method for manufacturing the LED chip with single-side light emission of the present invention is described below with reference to the accompanying drawings.

2 to 4 , the method for manufacturing a single-side light emitting LED chip of the present invention comprises the following steps:

Providing a substrate 11;

A DBR reflective layer 12 is disposed on the substrate, and a light emitting layer 13 is disposed on the DBR reflective layer;

The side surface of the light emitting layer 13 is tilted inwardly to form an inclined surface 131 by etching or sampling laser cutting process; preferably, the inclined surface 131 is an arc-shaped concave surface;

A side light blocking layer 21 is coated on the inclined surface 131; preferably, a light absorbing layer or a metal reflective layer is selected as the side light blocking layer 21;

A groove 132 is formed on the upper surface of the light-emitting layer 13 near the edge by etching or sampling laser cutting process, and a light-blocking material 22 is filled in the groove 132; preferably, a light-absorbing material or a metal reflective material is selected as the light-blocking material 22;

An electrode 14 is provided, and the electrode 14 is placed on the light-emitting layer 13 and electrically connected to the light-emitting layer 13 .

The LED chip with single-side light emission and the manufacturing method thereof of the present invention have the following beneficial effects:

The first light-blocking structure is formed by coating a side light-blocking layer on the side of the light-emitting layer, and the second light-blocking structure is formed by filling a light-blocking material in the groove near the edge of the light-emitting layer, thereby completely blocking light from leaking from the side of the light-emitting layer and ensuring that the light-emitting layer only emits light from the upper surface, which meets the requirements of high-precision light sources for optical encoders.

The present invention is described in detail above in conjunction with the embodiments of the accompanying drawings. A person skilled in the art can make various variations of the present invention according to the above description. Therefore, certain details in the embodiments should not constitute a limitation of the present invention, and the scope of protection of the present invention shall be defined by the scope of the attached claims.

Claims (9)

1. A single-side LED chip, comprising: a substrate; a reflective layer disposed on the upper surface of the substrate; a light-emitting layer disposed on the upper surface of the reflective layer, the side of the light-emitting layer being covered with a side light-blocking layer, and a groove being formed in the light-emitting layer, the groove being located near the edge of the upper surface of the light-emitting layer, the groove being filled with a light-blocking material, the light-emitting layer comprising an N-type semiconductor layer, an intrinsic semiconductor layer located on the N-type semiconductor layer, and a P-type semiconductor layer located on the intrinsic semiconductor layer, the bottom of the groove being located at the bottom of the light-emitting layer and contacting the reflective layer, so that the light-emitting layer at this location is completely blocked by the groove; and An electrode electrically connected to the light emitting layer. 2 . The single-sided light emitting LED chip according to claim 1 , wherein the side surface of the light emitting layer is inclined inward to form an inclined surface. 3 . The single-side light emitting LED chip according to claim 2 , wherein the inclined surface is an arc-shaped concave surface. 4. The single-sided light emitting LED chip according to claim 1 or 2, characterized in that the side light blocking layer is a light absorbing layer; and the light blocking material is a light absorbing material. 5. The single-sided light emitting LED chip according to claim 1 or 2, characterized in that the side light blocking layer is a metal reflective layer; and the light blocking material is a metal reflective material. 6. The single-side light emitting LED chip according to claim 1, characterized in that: An upper light-blocking layer is coated on the upper surface of the light-emitting layer between the groove and the edge of the light-emitting layer, one side of the upper light-blocking layer is connected to the side light-blocking layer, and the other side of the upper light-blocking layer is connected to the light-blocking material. 7. A method for manufacturing a single-side light emitting LED chip, characterized by comprising the following steps: providing a substrate; A reflective layer is arranged on the substrate, a light-emitting layer is arranged on the reflective layer, and a side light-blocking layer is coated on the side of the light-emitting layer, wherein the light-emitting layer comprises an N-type semiconductor layer, an intrinsic semiconductor layer located on the N-type semiconductor layer, and a P-type semiconductor layer located on the intrinsic semiconductor layer; A groove is formed in the light-emitting layer so that the groove is located near the edge of the upper surface of the light-emitting layer, and a light-blocking material is filled in the groove. The bottom of the groove is located at the bottom of the light-emitting layer and contacts the reflective layer, so that the light-emitting layer at this location is completely blocked by the groove. An electrode is provided to electrically connect the electrode to the light emitting layer. 8. The method for manufacturing a single-side light emitting LED chip according to claim 7, further comprising: The side surface of the light emitting layer is processed to be inclined inward to form an inclined surface. 9. The method for manufacturing a single-side light emitting LED chip according to claim 7, further comprising: A light absorbing layer is selected as the side light blocking layer; and a light absorbing material is selected as the light blocking material.