A variable pattern light emitting diode and its preparation method and reflective sight

Abstract

The present invention discloses a variable pattern light emitting diode and a preparation method thereof and a reflective sight. The variable pattern light emitting diode has a transparent conductive layer on the upper surface of an epitaxial wafer, a plurality of light emitting areas are arranged on the transparent conductive layer, and an etching area is arranged outside the transparent conductive layer. A P-surface electrode is arranged on each of the light emitting areas, and the P-surface electrode extends to the N-surface through a through hole penetrating the epitaxial wafer. The present invention also provides a preparation method and application of the light emitting diode chip. The reflective sight includes a light emitting diode with a variable pattern of the present invention as a light source, and does not require a graticule. The light source utilization rate and LED reliability are improved.

Description

Technical Field

[0001] The invention relates to a variable pattern light emitting diode and a preparation method thereof and a reflective sight, belonging to the technical field of sight light sources. Background Art

[0002] A reflex sight is an optical sight without magnification. It uses the principle of spherical reflection to make the reflected light incident on the eye enter the observer's eye in parallel, so that the observer's eye can see the red dot without having to be on the central axis of the lens, which can improve the shooting accuracy when the target is moving or the body is moving. The light source part of the reflex sight currently includes laser light source, LED / LD light source, isotope radiation light source, etc.

[0003] An isotope radiation source uses visible light radiated by a radioactive element as a light source. Although its lifespan is very long, its cost is relatively high. An LED / LD light source is a light source in which a circular or other patterned graticule is placed in front of the LED / LD. The light emitted by the light source is restricted by the graticule and then directed to a reflector, which reflects the light into parallel light and emits it. It is characterized by its simple structure and low power consumption and is widely used. The reflective sight provided by CN 203012234U (201320015314.X) includes a light emitting diode LED for generating a light source, a light analyzer for reflecting the emitted light of the light emitting diode LED into parallel light, and a graticule arranged between the light emitting diode LED and the light analyzer. The light analyzer is an aspherical lens. Since the radius of curvature of the aspherical surface is different at different places, it is possible to make more parts of the incident light of the light analyzer (beam splitter) parallel to the light after transmission, thereby reducing parallax.

[0004] However, since most of the light emitted by the LED light source is blocked by the reticle, only a small amount of light is emitted, so the light source utilization rate is low. Improving the LED light source utilization rate is very important for LED light source reflective sights, and this application is proposed for this purpose. Summary of the invention

[0005] In view of the problems in the prior art, the present invention provides a variable pattern light emitting diode and a method for preparing the same.

[0006] The invention also provides the application of a variable pattern light emitting diode and a reflective sight including the variable pattern light emitting diode.

[0007] Terminology explanation:

[0008] Light-emitting diode: LED for short;

[0009] ITO film: indium tin oxide semiconductor transparent conductive film.

[0010] Epitaxial wafer P-side: the upper surface of the epitaxial wafer, the side coated with a transparent conductive layer.

[0011] N side of epitaxial wafer: the side away from the transparent conductive layer, the back side of the epitaxial wafer substrate.

[0012] ICP etching: inductively coupled plasma etching;

[0013] MOCVD: Metal Organic Chemical Vapor Deposition;

[0014] PECVD: plasma enhanced chemical vapor deposition;

[0015] Lift-off process: The lift-off process is an integrated circuit process.

[0016] GZO: Gallium zinc oxide.

[0017] To achieve the above object, the present invention provides the following technical solutions:

[0018] A light emitting diode (LED) with a variable pattern comprises an epitaxial wafer, a transparent conductive layer is evaporated on the upper surface of the epitaxial wafer, a plurality of light emitting areas and etching areas are arranged on the transparent conductive layer, a P-surface electrode is correspondingly arranged on each of the light emitting areas, and adjacent P-surface electrodes are insulated and separated; an insulating layer is coated or deposited on the surface of the etching area, and an N-surface electrode is evaporated on the N-surface of the epitaxial wafer.

[0019] More optimally, the number of the light-emitting areas is m, the number of the P-side electrodes is n, and the light-emitting diode can generate q types of light-emitting patterns, then: m = n, q = 2 n -1; m≥2. That is, each P-side electrode has a corresponding light-emitting area, and the number of P-side electrodes n determines the number of patterns that can be generated; preferably m=2-3. Preferably, the P-side electrode is composed of two or more metal film systems selected from Cr, Ti, Pd, Pt, Al, and Au.

[0020] The variable pattern light emitting diode of the present invention can not only replace the combination of the light source and the reticle in the traditional sight, generate light with a set pattern when in use, but also improve the utilization rate of the light source and reduce the cost on the basis of retaining the simple structure and low power consumption. In the prior art, a dot pattern or a cross pattern is generally used for target aiming, but the setting of the pattern has an inevitable disadvantage, that is, it cannot be changed according to the distance between the target and the reflective sight. When the target is far away, the aiming accuracy will be greatly reduced when the dot pattern or the cross pattern is used for aiming, and the aiming pattern needs to be replaced at this time; in view of this problem, the present invention has been improved to realize that the light emitting pattern of the light emitting diode is variable, which is suitable for a variety of use environments and has better practicality.

[0021] According to the present invention, the epitaxial wafer includes a substrate and an N-type ohmic contact layer, an N-type confinement layer, an active area, a P-type confinement layer and a P-type ohmic contact layer grown sequentially from bottom to top on the surface of the substrate; preferably, the substrate is any one of GaAs, GaN, SiC and silicon.

[0022] The transparent conductive layer material is ITO, ZnO or GZO, which serves as a current spreading layer to cover the entire epitaxial layer surface, which can achieve better current spreading and improve the conductivity of the light-emitting diode chip. According to the present invention, the surface of the transparent conductive layer has a plurality of light-emitting areas, each of which corresponds to a light-emitting pattern, and each light-emitting area is provided with a P-surface electrode for controlling the light emission of the light-emitting area. Adjacent P-surface electrodes are spaced apart to ensure the independence of each light-emitting pattern and avoid mutual influence between light-emitting areas.

[0023] According to the present invention, the portion other than the light-emitting area is an etching area, and the etching depth of the etching area extends from the transparent conductive layer to the N-type limiting layer. The present invention etches the active area together to ensure that the light-emitting area can form the required light-emitting pattern. The etching area is formed by ICP etching.

[0024] Preferably, the number of the light-emitting areas is 2, including light-emitting area A and light-emitting area B, and the P-surface electrode includes P-surface electrode A and P-surface electrode B; P-surface electrode A corresponds to light-emitting area A, and P-surface electrode B corresponds to light-emitting area B; P-surface electrode A controls light-emitting area A to emit light, and P-surface electrode B controls light-emitting area B to emit light. More preferably, the light-emitting pattern of the light-emitting area A is circular or cross-shaped, and the light-emitting pattern of the light-emitting area B is annular, and the circle and the annulus are concentric circles, and the circle is located inside the annulus. The intersection of the cross is located at the center of the annulus.

[0025] One of the embodiments of the present invention is: it has a P-surface electrode A and a P-surface electrode B, the P-surface electrode A corresponds to the light-emitting area A, and the P-surface electrode B corresponds to the light-emitting area B; the light-emitting pattern of the light-emitting area A is a circle, and the light-emitting pattern of the light-emitting area B is a ring; when the diode is manufactured, the P-surface electrode A is turned on, and the light-emitting pattern generated is a dot; when the P-surface electrode B is turned on, the light-emitting pattern generated is a ring; when the P-surface electrode A and the P-surface electrode B are turned on at the same time, the light-emitting patterns are a circle and a ring, and the circle is located at the center of the ring.

[0026] Another embodiment of the present invention is: the number of the light-emitting areas is 3, including light-emitting area A, light-emitting area B, and light-emitting area C, and the P-surface electrode includes P-surface electrode A, P-surface electrode B, and P-surface electrode C accordingly; P-surface electrode A corresponds to light-emitting area A, P-surface electrode B corresponds to light-emitting area B, and P-surface electrode C corresponds to light-emitting area C; preferably, the light-emitting pattern of the light-emitting area A is a circle, the light-emitting pattern of the light-emitting area B is a ring, and the light-emitting pattern of the light-emitting area C is a ring or a cross, the dot is located at the center of the ring, the two rings are concentric circles, and the two rings do not overlap. The intersection of the cross is located at the center of the ring.

[0027] Preferably, the P-side electrode extends to the N-side of the epitaxial wafer, forming a wire-free LED structure. Preferably, each P-side electrode extends to the N-side of the epitaxial wafer through a through hole penetrating the epitaxial wafer, or each P-side electrode extends to the N-side of the epitaxial wafer through a through hole penetrating the epitaxial wafer and the insulating layer of the etched area.

[0028] More optimally, the P-side electrode extends onto the insulating layer in the etched area outside the light-emitting area.

[0029] Preferably, the thickness of the transparent conductive layer is It is further preferred that the thickness of the transparent conductive layer is

[0030] According to the present invention, an insulating layer is deposited outside the N-face electrode region on the N-face of the epitaxial wafer, below the P-face extension electrode, and inside the through hole penetrating the epitaxial wafer.

[0031] A method for preparing a light-emitting diode with a variable pattern comprises the following steps: growing an epitaxial wafer; evaporating a transparent conductive layer; preparing a light-emitting area by photolithography and ICP etching; making a P-side electrode; thinning the epitaxial wafer substrate; making an N-side electrode; and cutting to obtain the LED tube core.

[0032] More optimally, the method further includes the steps of, after the epitaxial wafer substrate is thinned, ICP etching a through hole from the substrate to the P-side electrode and evaporating an insulating layer; and the step of making a P-side extended electrode on the N-side of the epitaxial wafer.

[0033] More specifically, each of the above steps preferably has one or more of the following conditions:

[0034] (1) Growth of epitaxial wafer: taking a substrate, and sequentially growing an N-type ohmic contact layer, an N-type confinement layer, an active region, a P-type confinement layer, and a P-type ohmic contact layer on the surface of the substrate by MOCVD to obtain an epitaxial wafer;

[0035] (2) Evaporation of transparent conductive layer: Place the epitaxial wafer with the N surface facing downward and the P surface facing upward in an electron beam evaporation table, and evaporate a transparent conductive layer on the P-type ohmic contact layer. The transparent conductive layer covers the entire surface of the epitaxial wafer. The thickness of the transparent conductive layer is

[0036] (3) Photolithography and ICP etching to prepare the light-emitting area, including:

[0037] a. Place the epitaxial wafer P surface upward on the coating machine chuck, apply photoresist, expose the luminous patterns of several luminous areas according to the set pattern, and then develop and etch to form several luminous areas on the surface of the transparent conductive layer. The surface of the luminous area is covered with photoresist and protected by the photoresist mask; the remaining part of the photoresist is etched away by the developer and etchant to facilitate subsequent ICP etching;

[0038] b. Place the epitaxial wafer P surface upward in the etcher, and perform ICP etching on the surface of the transparent conductive layer not covered by the photoresist, until the etching depth penetrates the active area to the N-type confinement layer to form an etched area; this step etches away the active area of ​​the etched area to ensure the accuracy of the subsequent light emitting pattern;

[0039] c. Place the etched epitaxial wafer in a degumming solution, the degumming solution temperature is controlled at 80-82°C, and the degumming time is 10-15min; then place the epitaxial wafer in an acetone solution, the acetone temperature is 50-52°C, and the time is 5-7min; then place the epitaxial wafer in ethanol, the ethanol temperature is 70-73°C, the time is 5-7min, cleaned with pure water, and dried with nitrogen; in this step, the degumming solution is used to remove the photoresist on the P side of the epitaxial wafer, and then placed in acetone to remove the residual degumming solution on the epitaxial wafer; then use ethanol to wash away the residual acetone on the chip, and finally dissolve ethanol in water to clean the entire P side of the epitaxial wafer thoroughly;

[0040] (4) Fabrication of P-side electrode

[0041] Take the epitaxial wafer after ICP etching, make an insulating layer on the surface of the etched area, and then make a P-side electrode on the transparent conductive layer; adjacent P-side electrodes are insulated and separated to ensure the accuracy of the pattern during subsequent light emission and avoid interference between light-emitting areas.

[0042] (5) After the P-side electrode is fabricated, the epitaxial wafer substrate is thinned to 140-170 μm.

[0043] (6) ICP etching of through holes from the substrate to the P-side electrode and evaporation of an insulating layer: ICP etching is as described in step (3). The evaporation of the insulating layer is performed by evaporating a SiO2 layer on the N-side of the epitaxial layer and the inner wall of the through hole by PECVD after the etching and stripping is completed. The SiO2 in the N-side electrode area and the SiO2 in the contact area between the through hole and the P-side electrode are then etched away by a photolithography process.

[0044] (7) Fabricating N-side electrode and P-side extended electrode: as in step (4).

[0045] (8) Place the epitaxial wafer with its P surface facing upward on a saw blade machine and perform full cutting to obtain the LED die.

[0046] More optimally, in step (4), an epitaxial wafer after ICP etching is taken, an insulating dielectric film is coated on the etched area, and cured at 340-360° C. for 28-32 minutes, wherein the thickness of the insulating dielectric film is the same as the depth of the ICP etching, to form an insulating layer; wherein the insulating dielectric film is benzocyclobutene (BCB) or polyimide (PI).

[0047] Another optional method is that in step (4) of the present invention, SiO2 or SiN is deposited on the P surface of the epitaxial wafer after the ICP etching is completed. x Then, the surface of each light-emitting area is covered with SiO2 or SiN x Stripping, making SiO2 or SiN x Covering the surface of the area etched by ICP, that is, forming an insulating layer on the surface of the etched area, can play a role in insulation protection. More optimally, PECVD method is used to deposit SiO2, wherein the thickness of SiO2 is

[0048] Coating the insulating dielectric film BCB (benzocyclobutene) or PI (polyimide) on the surface of the etched area is more effective than depositing SiO2 or SiN x The insulating layer, BCB (benzocyclobutene) and PI (polyimide) can not only play the role of insulating protection, but also can flatten the surface of the etched area, so that the height of the insulating layer is consistent with the height of the transparent conductive layer, which is convenient for the subsequent production of the P-side electrode and has better practicality.

[0049] Preferably, in step (6), the material of the evaporated insulating layer in the through hole is SiO2 or SiN x .

[0050] According to the present invention, in step (6), the through hole avoids the light-emitting area or passes through the light-emitting area.

[0051] According to the present invention, in step (4), the P-side electrode is extended to the non-luminous area outside the transparent conductive layer.

[0052] Preferably, in step (4), a lift-off process is used to fabricate a P-side electrode on the transparent conductive layer.

[0053] Unless otherwise specified in the preparation method of the present invention, the preparation method can be carried out according to the prior art in the art.

[0054] The invention discloses an application of a variable pattern light emitting diode, which is used as a light source of a reflective sight. As a graticule is not required, the utilization rate of the light source is improved.

[0055] The present invention also provides a reflective sight, which comprises the light emitting diode with variable patterns as a light source and a reflector for reflecting the emitted light of the light emitting diode LED into parallel light, and does not require a reticle.

[0056] A preferred solution of the reflective sight of the present invention is that when the P-surface electrode A of the light-emitting diode is turned on, the light-emitting pattern generated is a dot; when the P-surface electrode B of the light-emitting diode is turned on, the light-emitting pattern generated is a ring; when the P-surface electrode A and the P-surface electrode B of the light-emitting diode are turned on at the same time, the light-emitting pattern is a dot and a ring. When the distance to the target is relatively close, the P-surface electrode A can be turned on to aim at the dot; when the target is relatively far, the P-surface electrode B can be turned on to aim at the dot; at the same time, the dot and the ring can be used for aiming at the same time as needed to further improve the aiming accuracy.

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] When the present invention is manufactured, firstly, the epitaxial wafer is grown, then a transparent conductive layer is evaporated on the surface of the epitaxial wafer, then a photoresist is coated on the surface of the transparent conductive layer, the target luminous pattern is exposed by the photoresist, and several luminous areas (such as luminous area A and luminous area B) are formed by development and etching; at this time, the photoresist exists on the surface of each luminous area, which plays a role of mask protection, and at this time, the area not covered by the photoresist is ICP etched, and the etching depth reaches the N-type restriction layer to form an etched area; then, an insulating layer is prepared on the surface of the etched area, and the insulating layer plays a role of insulating protection, and finally, the corresponding P-side electrode (such as P-side electrode A and P-side electrode B) and N-side electrode are cut to obtain the LED tube core. In the preferred scheme, a P-side electrode through hole and a P-side extension electrode are also provided.

[0059] When the P-surface electrode is produced, in order to achieve the variability of the luminescent pattern, a corresponding luminescent area is designed for each P-surface electrode; when there are luminescent areas A and B on the surface of the epitaxial wafer, the P-surface electrode A is produced first, and the P-surface electrode A is connected to the luminescent area A to control the luminescence of the luminescent area A. At this time, in order to avoid the influence between the P-surface electrode A and the P-surface electrode B, and to ensure the integrity and accuracy of the subsequent luminescent pattern, the P-surface electrode A and the P-surface electrode B are isolated from each other.

[0060] The variable pattern light emitting diode of the present invention has a simple structure and a reasonable design of the preparation steps. The prepared light emitting diode can be used alone and does not need to cooperate with the graticule plate when used in a reflective sight. The light emitting diode itself can emit the required pattern. At the same time, the light emitting pattern of the diode prepared by the present technical solution is variable and can be changed according to the distance between the reflective sight and the target, which has high practicality. In addition, the graticule plate of the existing reflective sight is an optical component, which has high requirements for transparency and cleanliness, is costly, occupies the space of the reflective sight and is not easy to disassemble. The light emitting diode of the present invention does not need a graticule plate when used as a light source for a reflective sight, which improves the utilization rate of the light source while ensuring the advantages of simple structure and low power consumption.

[0061] The present invention also uses a P-side extension electrode to make the P-side electrode on the N-side, without the need for wire bonding, and solder paste is applied on the corresponding PCB (printed circuit board) board to complete the wire bonding at the same time as the die is fixed. The wire-free LED structure of the present invention overcomes the problem of low die yield rate caused by wire bonding, and improves the yield rate of LED products. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the present invention;

[0063] Figure 2 This is a schematic diagram of the overall structure of Embodiment 2 of the present invention;

[0064] Figure 3 This is a schematic diagram of the overall structure of Embodiment 3 of the present invention;

[0065] Figure 4 Schematic diagram of the P-side electrode pattern (P-side view) of an embodiment of the present invention;

[0066] Figure 5 Schematic diagram of the extended electrode pattern of the P-side electrode of an embodiment of the present invention (N-side view); A is the extended electrode of the P-side electrode A, B is the extended electrode of the P-side electrode B, and the black circular hole is the through hole connecting the P-side electrode.

[0067] In the figure: 1-substrate, 2-N-type ohmic contact layer, 3-N-type confinement layer, 4-active region, 5-P-type confinement layer, 6-P-type ohmic contact layer, 7-transparent conductive layer, 8-insulating layer (dielectric film), 9-P-surface electrode, 10-N-surface electrode, 11-P-surface electrode extension electrode, 12-insulating layer (SiO2 or SiN x ), 13-Figure A, 14, Figure B.

[0068] Figure 6 This is a photograph of the light-emitting pattern of the embodiment of the light-emitting diode with a variable pattern in the present embodiment 1.

[0069] Figure 7 It is a schematic diagram of the light emitting pattern of the light emitting diode with a variable pattern according to the second embodiment of the present invention.

[0070] Figure 6 , Figure 7 In the figure, the left picture is a dot, the middle picture is a ring, and the right picture is a dot within a ring.

[0071] Figure 8 This is the reflective sight of Example 4, in which 20. PCB board, 21. variable pattern LED, 22. first reflector, 23. second reflector, 24. magnifier. DETAILED DESCRIPTION

[0072] The present invention will be further described below in conjunction with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0073] In this embodiment, the substrate 1 is a GaAs substrate; the material of the transparent conductive layer 7 is ITO. The P-side electrode is composed of CrTiAl, CrPtAu, CrPdAu or CrAu metal film system. The N-side electrode is AuGeNi or AuGe.

[0074] Embodiment 1:

[0075] S1: Take a substrate 1, and sequentially grow an N-type ohmic contact layer 2, an N-type confinement layer 3, an active region 4, a P-type confinement layer 5, and a P-type ohmic contact layer 6 on the surface of the substrate 1 by using a MOCVD method to obtain an epitaxial wafer;

[0076] S2: Place the epitaxial wafer with N surface downward and P surface upward in an electron beam evaporation station, and evaporate an ITO film transparent conductive layer 7 on the P-type ohmic contact layer 6. The ITO film covers the entire surface of the epitaxial wafer; the thickness of the ITO film is

[0077] S3-1: Place the epitaxial wafer P surface upward on the chuck of the coating machine, apply photoresist, and expose the luminous pattern A (circle) of the luminous area A and the luminous pattern B (ring) of the luminous area B. The circle and the ring are concentric, and the circle is located at the center of the ring. Then, development and etching are performed. At this time, the luminous area A and the luminous area B are formed on the surface of the ITO film 7. The surfaces of the luminous area A and the luminous area B are covered with photoresist.

[0078] S3-2: placing the epitaxial wafer with the P surface facing upward in an etcher, and performing ICP etching on the area on the surface of the ITO film not covered by the photoresist, until the etching depth penetrates the active area 4 to the N-type restriction layer 3, thereby forming an etching area;

[0079] S3-3: placing the etched epitaxial wafer into a degumming solution, the temperature of the degumming solution is controlled at 80°C, and the degumming time is 10 minutes; then placing the epitaxial wafer into an acetone solution, the acetone temperature is 50°C, and the time is 5 minutes; then placing the epitaxial wafer into ethanol, the ethanol temperature is 70°C, and the time is 5 minutes, washing with pure water, and drying with nitrogen;

[0080] S4: Take the epitaxial wafer after ICP etching, apply an insulating dielectric film on the etched area, and cure it at 340°C for 28 minutes, wherein the thickness of the insulating dielectric film is the same as the depth of ICP etching, to form an insulating layer 8; wherein the insulating dielectric film is BCB; and then use a lift-off process to make P-side electrodes A and P-side electrodes B on the ITO film 7; Figure 4 The P electrode can also be extended to the non-luminous area to further improve the quantum efficiency.

[0081] S5: After the P-side electrode A and the P-side electrode B are manufactured, the substrate 1 of the epitaxial wafer is thinned to 140 μm;

[0082] S6: Apply glue on both sides of the thinned epitaxial wafer, then form a mask of the required pattern on the N side, and use an ICP etcher to etch two through holes from the N side to the P side electrode A and the P side electrode B respectively. The two through holes are located on both sides of the active area 4 (such as Figure 1 As shown), avoid the active area (light-emitting area). Then, the debonding is performed; after the debonding is completed, a SiO2 layer 12 is evaporated on the surface of the epitaxial layer by PECVD, and its thickness is 1500 angstroms. Then, the SiO2 in the N-side electrode area and the SiO2 in the contact area between the through hole and the P-side electrode are etched away by photolithography (the SiO2 on the inner wall of the through hole is retained).

[0083] S7: Using lift-off process to make N-side electrode 10 on the substrate, and making P-side electrode extension electrode on the substrate and SiO2 film in the through hole to form a wire-free structure; Figure 5 shown.

[0084] S8: Place the epitaxial wafer with its P surface facing upward on a saw blade machine and perform full cutting to obtain an LED die. Figure 1 The luminous pattern is shown as Figure 6 shown.

[0085] In this embodiment, the substrate 1 is a GaAs substrate 1, and the material of the P-type ohmic contact layer 7 is ITO. The P-side electrode and the P-side extension electrode are CrTiAl, and the N-side electrode is AuGeNi.

[0086] The light emitting diode (LED) with variable pattern prepared in this embodiment has a structure as shown in FIG. Figure 1As shown, it includes an epitaxial wafer, an ITO film transparent conductive layer 7 is vapor-deposited on the upper surface of the epitaxial wafer, and two light-emitting areas and an etching area are arranged on the ITO film transparent conductive layer. A P-surface electrode is correspondingly arranged on each of the light-emitting areas, and adjacent P-surface electrodes are insulated and separated; an insulating layer 8 is provided on the surface of the etching area, and an N-surface electrode 10 is vapor-deposited on the N surface of the epitaxial wafer. The light-emitting area includes a light-emitting area A and a light-emitting area B, and the P-surface electrode includes a P-surface electrode A and a P-surface electrode B; the P-surface electrode A controls the light-emitting area A to emit light, and the P-surface electrode B controls the light-emitting area B to emit light. The light-emitting pattern of the light-emitting area A is circular, and the light-emitting pattern of the light-emitting area B is annular. The circle is located at the center of the annular ring. The P-surface electrode A and the P-surface electrode B extend to the insulating layer of the etching area outside the light-emitting area.

[0087] Embodiment 2:

[0088] S1: Take a substrate 1, and sequentially grow an N-type ohmic contact layer 2, an N-type confinement layer 3, an active region 4, a P-type confinement layer 5, and a P-type ohmic contact layer 6 on the surface of the substrate 1 by using a MOCVD method to obtain an epitaxial wafer;

[0089] S2: Place the epitaxial wafer with the N surface facing downward and the P surface facing upward in an electron beam evaporation station, and evaporate an ITO film transparent conductive layer 7 on the P-type ohmic contact layer 6. The ITO film 7 covers the entire surface of the epitaxial wafer; the thickness of the ITO film is

[0090] S3-1: Place the epitaxial wafer P surface upward on the chuck of the coating machine, apply photoresist, and expose the luminous pattern A (circle) of the luminous area A and the luminous pattern B (ring) of the luminous area B, wherein the circle is located at the center of the ring and the circle and the ring are concentric; then perform development and etching, and at this time, the luminous area A and the luminous area B are formed on the surface of the ITO film 7, and the surfaces of the luminous area A and the luminous area B are covered with photoresist;

[0091] S3-2: placing the epitaxial wafer with the P surface facing upward in an etcher, and performing ICP etching on the area on the surface of the ITO film 7 that is not covered by the photoresist, until the etching depth penetrates the active area 4 to the N-type restriction layer 3, thereby forming an etching area;

[0092] S3-3: placing the etched epitaxial wafer into a degumming solution, the temperature of the degumming solution is controlled at 80°C, and the degumming time is 10 minutes; then placing the epitaxial wafer into an acetone solution, the acetone temperature is 50°C, and the time is 5 minutes; then placing the epitaxial wafer into ethanol, the ethanol temperature is 70°C, and the time is 5 minutes, washing with pure water, and drying with nitrogen;

[0093] S4: Take the epitaxial wafer after ICP etching and deposit SiO2 on the surface of the ITO film using PECVD, where the thickness of SiO2 is Then, a stripping process is used to remove the SiO2 covering the luminous areas A and B on the ITO surface, and the SiO2 on the surface of the etched area is retained to form an insulating layer 8; and a lift-off process is used to make P-side electrodes A and P-side electrodes B on the ITO film 7; Figure 4 The P electrode can also be extended to the non-luminous area to further improve the quantum efficiency.

[0094] S5: After the P-side electrodes A and B are fabricated, the substrate 1 of the epitaxial wafer is thinned to 150 μm;

[0095] S6: Apply glue on both sides of the thinned epitaxial wafer, then form a mask of the required pattern on the N side, and use an ICP etcher to etch two through holes from the N side to the P side electrode A and the P side electrode B respectively. The two through holes are located on both sides of the active area 4, avoiding the active area (light emitting area). Then, debonding is performed; after debonding, a SiO2 layer 12 is evaporated on the surface of the epitaxial layer by PECVD, with a thickness of 2500 angstroms, and then the SiO2 in the N side electrode area and the SiO2 in the contact area between the through hole and the P side electrode are etched away by photolithography (the SiO2 on the inner wall of the through hole is retained).

[0096] S7: Using lift-off process to make N-side electrode 10 on the substrate, and making P-side electrode extension electrode on the substrate and SiO2 film 12 in the through hole to form a wire-free structure; Figure 5 shown.

[0097] S8: Place the epitaxial wafer with its P surface facing upward on a saw blade machine and perform full cutting to obtain an LED die. Figure 2 The thickness of the insulating layer on the surface of the etched area is less than the depth of the etching, and the insulating layer and the ITO film are in a step state. The LED light emitting pattern is as shown in FIG. Figure 7 shown.

[0098] In this embodiment, the substrate 1 is a GaAs substrate 1, and the material of the P-type ohmic contact layer 7 is ITO. The P-side electrode and the P-side extension electrode are CrPtAu, and the N-side electrode is AuGe.

[0099] Embodiment 3:

[0100] As described in Example 1, the difference is that in step S4, the P-side electrode A and the P-side electrode B are only located in the light-emitting area, and the two through holes in step S6 penetrate the active area 4. Figure 3 The luminous pattern is shown as Figure 7 shown.

[0101] Luminescence experiment:

[0102] The light-emitting diode prepared by any one of Examples 1-3 can produce a specific light-emitting pattern after being lit, and when in use, the light-emitting pattern can be replaced according to the conduction selection of the P-side electrode. The wire bonding is completed at the same time as the packaging and solid crystal. When used in a reflective sight, the use effect is excellent.

[0103] When the light-emitting diode is completed, the P-side electrode A is turned on, and the light-emitting pattern generated is a dot ( Figure 6 , Figure 7 Left figure); when the P-side electrode B is turned on, the generated luminous pattern is a ring ( Figure 6 , Figure 7 Middle Figure); When the P-side electrode A and the P-side electrode B are turned on at the same time, the luminous pattern is dots and rings ( Figure 6 , Figure 7 right). Figure 6 This is a photo of the luminous patterns produced by turning on the P-side electrode, which are dots, rings, and rings outside dots.

[0104] Example 4: Reflex sight

[0105] A reflective sight includes a light source and a reflector, wherein the light source is a variable pattern light emitting diode 21 described in the present invention, such as any one of embodiments 1-3. When the distance to the target is relatively close, the light pattern generated by turning on the P-surface electrode A is a dot. When the target is relatively far away, the light pattern generated by turning on the P-surface electrode B is a ring; the P-surface electrodes A and B can also be turned on at the same time, and the light pattern is a concentric ring around the dot, and the dot and the ring are used for aiming at the same time, so as to further improve the aiming accuracy.

[0106] Reflex sight structure if any Figure 8 As shown, a PCB board 20, a variable pattern LED 21, a first reflector 22, a second reflector 23, and a magnifying mirror 24 are sequentially arranged in the direction of the optical path. The structure of the reflective sight is not limited to this, and other applicable structures are also possible.

[0107] It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the scope of the present invention is not limited to the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

Claims

1. A light-emitting diode with a variable pattern, comprising an epitaxial wafer, wherein a transparent conductive layer is evaporated on the upper surface of the epitaxial wafer, a plurality of light-emitting areas are arranged on the transparent conductive layer, and an etching area is arranged outside the transparent conductive layer, wherein: A P-surface electrode is correspondingly arranged on each of the light-emitting areas, and adjacent P-surface electrodes are insulated and separated, and the P-surface electrode extends to the N-surface of the epitaxial wafer through a through hole; an insulating layer is deposited on the surface of the etched area, and an N-surface electrode is evaporated on the N-surface of the epitaxial wafer; the number of the light-emitting areas is m, the number of the P-surface electrodes is n, and the number of light-emitting patterns that the diode can generate is q, then: m=n, q=2 n -1; m=2 or 3; When the number of the light-emitting areas is 2, the light-emitting areas include light-emitting area A and light-emitting area B, the P-surface electrode includes P-surface electrode A and P-surface electrode B, the P-surface electrode A corresponds to the light-emitting area A, and the P-surface electrode B corresponds to the light-emitting area B; the P-surface electrode A controls the light-emitting area A to emit light, and the P-surface electrode B controls the light-emitting area B to emit light; the light-emitting pattern of the light-emitting area A is a dot, and the light-emitting pattern of the light-emitting area B is a ring, the dot and the ring are concentric circles, and the dot is located inside the ring; or, When the number of the light-emitting zones is 3, the light-emitting zones include light-emitting zone A, light-emitting zone B, and light-emitting zone C, and correspondingly the P-surface electrodes include P-surface electrodes A, P-surface electrodes B, and P-surface electrodes C; P-surface electrode A corresponds to light-emitting zone A, P-surface electrode B corresponds to light-emitting zone B, and P-surface electrode C corresponds to light-emitting zone C; the light-emitting pattern of the light-emitting zone A is a dot, the light-emitting pattern of the light-emitting zone B is a ring, and the light-emitting pattern of the light-emitting zone C is a ring or a cross, the dot is located at the center of the ring, the two rings are concentric circles, and the two rings do not overlap; the intersection of the cross is located at the center of the ring.

2. The variable pattern light emitting diode according to claim 1, characterized in that: Include one or more of the following conditions: i The P-side electrode extends to the insulating layer in the etched region outside the light-emitting region; ii. The transparent conductive layer has a thickness of 500-3000Å; iii. The epitaxial wafer comprises a substrate and an N-type ohmic contact layer, an N-type confinement layer, an active region, a P-type confinement layer and a P-type ohmic contact layer grown sequentially from bottom to top on the surface of the substrate; the substrate is GaAs, GaN, SiC or silicon.

3. The method for preparing a light-emitting diode with a variable pattern as claimed in claim 1 or 2, characterized in that: The steps include: (1) Growth of epitaxial wafer: Take a substrate and use MOCVD to sequentially grow an N-type ohmic contact layer, an N-type confinement layer, an active region, a P-type confinement layer and a P-type ohmic contact layer on the substrate surface to obtain an epitaxial wafer; (2) Evaporation of transparent conductive layer: Place the epitaxial wafer with its N side facing downward and its P side facing upward in an electron beam evaporation table, and evaporate a transparent conductive layer on the P-type ohmic contact layer. The transparent conductive layer covers the entire surface of the epitaxial wafer. (3) Photolithography and ICP etching to prepare the light-emitting area, including: a. Place the epitaxial wafer P surface upward on the coating machine chuck, apply photoresist, expose the luminous patterns of several luminous areas according to the set pattern, and then develop and etch to form several luminous areas on the surface of the transparent conductive layer. The surface of each luminous area is covered with photoresist and protected by the photoresist mask; the remaining part of the photoresist is etched away by the developer and etchant to facilitate subsequent ICP etching; b. Place the epitaxial wafer P-side up in the etcher, and perform ICP etching on the area on the surface of the transparent conductive layer not covered by the photoresist, until the etching depth penetrates the active area to the N-type confinement layer to form an etching area; c. Place the etched epitaxial wafer in a degumming solution, the temperature of which is controlled at 80-82°C, and the degumming time is 10-15 minutes; then place the epitaxial wafer in an acetone solution, the acetone temperature is 50-52°C, and the time is 5-7 minutes; then place the epitaxial wafer in ethanol, the ethanol temperature is 70-73°C, and the time is 5-7 minutes, then rinse with pure water and dry with nitrogen; (4) Fabrication of P-side electrode Take the epitaxial wafer after ICP etching, make an insulating layer on the surface of the etching area, and then make a P-side electrode on the transparent conductive layer; adjacent P-side electrodes are insulated and separated; (5) After the P-side electrode is fabricated, the epitaxial wafer substrate is thinned to 140-170 μm; (6) ICP etching of through holes from the substrate to the P-side electrode and evaporation of an insulating layer, wherein the evaporation of the insulating layer is performed by evaporating a SiO2 layer on the N-side of the epitaxial layer and the inner wall of the through hole by PECVD, and then etching away the SiO2 in the N-side electrode area and the SiO2 in the contact area between the through hole and the P-side electrode by photolithography; (7) Fabricating N-side electrode and P-side extended electrode; (8) Place the epitaxial wafer with its P surface facing upward on a saw blade and perform full cutting to obtain the LED core.

4. The method for preparing a variable pattern light emitting diode according to claim 3, characterized in that: Each step includes one or more of the following conditions: i. In the step of making the P-side electrode, take the epitaxial wafer after the ICP etching, apply an insulating dielectric film on the etched area, and cure it at 340-360°C for 28-32min to form an insulating layer; ii. Deposition of SiO2 or SiN on the P surface of the epitaxial wafer after ICP etching x Then, the surface of each light-emitting area is covered with SiO2 or SiN x Stripping, making SiO2 or SiN x Covering the surface of the area etched by ICP, that is, forming an insulating layer on the surface of the etched area; iii. The P-side electrode extends to the non-luminous region outside the transparent conductive layer; iv. The through hole avoids the light-emitting area or passes through the light-emitting area.

5. The method for preparing a variable pattern light emitting diode according to claim 3, characterized in that: The thickness of the insulating dielectric film is the same as the depth of ICP etching.

6. The method for preparing a variable pattern light emitting diode according to claim 3, characterized in that: The insulating dielectric film is benzocyclobutene or polyimide.

7. The method for preparing a variable pattern light emitting diode according to claim 3, characterized in that: SiO2 is deposited by PECVD with a thickness of 1000-3000 Å.

8. Use of the variable pattern light emitting diode according to any one of claims 1 or 2 as a light source for a reflective sight.

9. A reflective sight, comprising a light emitting diode with a variable pattern as described in claim 1 or 2 as a light source, when the P-surface electrode A of the light emitting diode is turned on, the light emitting pattern generated is a dot; when the P-surface electrode B of the light emitting diode is turned on, the light emitting pattern generated is a ring; when the P-surface electrode A and the P-surface electrode B of the light emitting diode are turned on at the same time, the light emitting patterns are dots and rings; when the distance to the target is relatively close, the P-surface electrode A is turned on and the dots are used for aiming; when the target is relatively far, the P-surface electrode B is turned on and the ring is used for aiming; it is also possible to turn on the P-surface electrode A and the P-surface electrode B of the light emitting diode at the same time and use the dots and the ring for aiming.

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