Light emitting diode, light emitting device and projector

Abstract

The present application discloses a light emitting diode, a light emitting device and a projector, and relates to the field of semiconductor technology. In a light emitting diode, the diode body includes a second electrode layer, a first insulating layer and an epitaxial stack from bottom to top; the epitaxial stack includes a second semiconductor layer, a light emitting layer and a first semiconductor layer from bottom to top; wherein the first insulating layer is provided with a plurality of second contact holes extending through the second semiconductor layer and the light emitting layer to the first semiconductor layer, and the second electrode layer is electrically connected to the first semiconductor layer through the second contact holes; a flexible film is provided on the first semiconductor layer, and the thickness of the flexible film is a first thickness, and the first thickness is not greater than 10 μm. The present application can suppress the noise generated by the light emitting diode.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a light emitting diode and a method for preparing the same, a light emitting device and a projector. Background Art

[0002] At present, a projector generally includes a driving circuit, a light emitting device, a modulation circuit, and a DMD (Digital Micromirror Device) light modulator. The driving circuit is used to output a periodic switching signal, and each period of the switching signal includes a first time period and a second time period. The light emitting device is electrically connected to the driving circuit, and the switching signal is used to control the light emitting device to maintain a lit state in the first time period, and the switching signal is used to control the light emitting device to maintain an extinguished state in the second time period. The modulation circuit is electrically connected to the driving circuit, and the switching signal is used to control the modulation circuit to output a light modulation signal in the first time period. The DMD light modulator is electrically connected to the modulation circuit and is used to receive the illumination light emitted by the light emitting device; the light modulation signal is used to control the DMD light modulator in the first time period to convert the illumination light into image light for projecting a picture.

[0003] Generally, the illumination light emitted by the light emitting device is usually provided by a light emitting diode. Since the switch signal controls the light emitting diode to switch back and forth between a lighting state and an extinguishing state, its essence is to switch the light emitting diode back and forth.

[0004] Among them, the light-emitting diode often includes a second electrode layer, a first insulating layer and an epitaxial stack. The first insulating layer is disposed on the second electrode layer and is continuously distributed in the first region and the second region. The epitaxial stack is disposed on the first insulating layer and is distributed in the first region; the epitaxial stack includes a second semiconductor layer, a light-emitting layer and a first semiconductor layer in order from bottom to top. The first insulating layer is provided with a plurality of second contact holes extending through the second semiconductor layer and the light-emitting layer to the first semiconductor layer, and the second electrode layer is electrically connected to the first semiconductor layer through the second contact holes.

[0005] The inventors found that the current density in the second contact hole of the light-emitting diode is not less than 3A / mm 2 When the LED is switched on and off, it will cause the LED to produce a howling noise.

[0006] Therefore, how to make the current density in the second contact hole of the light-emitting diode not less than 3A / mm 2 At the same time, suppressing the noise generated by the light-emitting diode is still a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0007] In view of this, in order to solve the above technical problems, the present application provides a light emitting diode and a method for preparing the same, a light emitting device and a projector.

[0008] In order to solve the above technical problems, one of the technical solutions adopted in the present application provides a light-emitting diode, which includes a diode body and a flexible film in order from bottom to top, the diode body includes a second electrode layer, a first insulating layer and an epitaxial stack in order from bottom to top; the epitaxial stack includes a second semiconductor layer, a light-emitting layer and a first semiconductor layer in order from bottom to top; The first insulating layer is provided with a plurality of second contact holes extending through the second semiconductor layer and the light-emitting layer to the first semiconductor layer, and the second electrode layer is electrically connected to the first semiconductor layer through the second contact holes; the flexible film is provided on the first semiconductor layer, and the thickness of the flexible film is the first thickness, and the first thickness is not greater than 10 μm.

[0009] In order to solve the above technical problems, another technical solution adopted by the present application is to provide a light-emitting device, which includes: Package substrate; The lens is disposed on the packaging substrate and encloses an air cavity with the packaging substrate; and a light emitting diode, wherein the light emitting diode is the light emitting diode mentioned above; the light emitting diode is arranged on the packaging substrate and is located in the air cavity; The side of the flexible film facing away from the first semiconductor layer faces the lens, the light emitting diode is used to emit illumination light, and the lens is used to transmit the illumination light so that the illumination light can be emitted.

[0010] In order to solve the above technical problems, another technical solution adopted by the present application is to provide a projector, which includes: A driving circuit, configured to output a periodic switching signal, wherein each period of the switching signal includes a first time period and a second time period; And a light-emitting device is electrically connected to the driving circuit, the light-emitting device is the above-mentioned light-emitting device; the switch signal is used to control the light-emitting device to maintain a lit state in the first time period; the switch signal is used to control the light-emitting device to maintain an extinguished state in the second time period.

[0011] Beneficial effects: Different from the prior art, the present invention has at least two effects. First, the first thickness is not greater than 10 μm, which is beneficial to the overall thinness of the light-emitting diode, and further beneficial to the heat dissipation of the light-emitting diode, so that the current density of the light-emitting diode in the second contact hole is not less than 3A / mm 2 Even not less than 6A / mm 2 In addition, the flexible film is disposed on the first semiconductor layer, so that when the light-emitting diode is switched back and forth under the control of the switch signal, the flexible film can suppress the resonance between the diode body and the diffusion capacitor, thereby suppressing the light-emitting diode from generating noise. That is, the current density of the light-emitting diode in the second contact hole of the present application is not less than 3A / mm 2Even not less than 6A / mm 2 When the power is turned on, it can effectively suppress the generation of noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic diagram of the structure of the diode body provided in step S100 in the method for preparing a light emitting diode of the present application, Figure 1 It is obtained by looking down at the diode body from the side of the epitaxial stack facing away from the first insulating layer; Figure 2 is along Figure 1 A schematic cross-sectional view taken along the interception line YY; Figure 3 yes Figure 2 Dimensioning diagram of Figure 4 yes Figure 2 Schematic diagram of the structure of the first insulating layer, Figure 4 It is obtained by looking up at the first insulating layer from the side of the first insulating layer facing away from the epitaxial stack; Figure 5 is a schematic diagram of the structure formed in step S200 in the method for preparing a light emitting diode of the present application; Figure 6 is a schematic diagram of the structure formed in step S110 in the method for preparing a light emitting diode of the present application; Figure 7 is a schematic diagram of a structure formed in step S120 in the method for preparing a light emitting diode of the present application; Figure 8 is a schematic diagram of a first stacked structure provided in step S130 in the method for preparing a light emitting diode of the present application; Fig. 9 is a schematic diagram of a structure formed in step S130 in the method for preparing a light emitting diode of the present application; Fig.10 is a schematic diagram of a structure formed in step S140 in the method for preparing a light emitting diode of the present application; Fig.11 is a schematic diagram of a structure formed in step S150 in the method for preparing a light emitting diode of the present application; Fig.12 is a schematic diagram of the structure formed in step S160 in the method for preparing a light emitting diode of the present application; Fig.13 is a schematic diagram of a structure formed in step S170 in the method for preparing a light emitting diode of the present application; Fig.14 This is a physical photo of the first light-emitting diode of the experimental group; Fig.15 is a schematic diagram of a slice of the first light-emitting diode of the experimental group; Fig.16 is the audio waveform of the noise of the first LED of the experimental group; Fig.17 is the audio waveform of the noise of the second LED of the control group; Fig.18 are energy density curves corresponding to the second light emitting diode of the control group and the first light emitting diode of the experimental group, respectively, and the energy density curves are used to represent the energy density of the luminous intensity at different light output angles; Fig.19 It is a schematic diagram of the structure of the light-emitting device of the present application; Fig. 20 It is a structural schematic diagram of the projector of this application.

[0013] Description of reference numerals: Light-emitting diode 10; first light-emitting diode 10a; diode body 100; flexible film 200; second electrode layer 110; first insulating layer 120; second contact hole 121; epitaxial stack 130; second semiconductor layer 131; light-emitting layer 132; first semiconductor layer 133; second opening 134; current spreading layer 140; second insulating layer 150; first opening 151; first contact hole 152; first electrode 160; ohmic contact layer 170; bonding metal layer 180; first bonding layer 181; second bonding layer 182; conductive substrate 190; passivation protection layer 191; growth substrate 300; first region A; second region B; first area S1; third area S3; fourth area S4; first spacing d1; first thickness h1; second thickness h2; Light emitting device 400; packaging substrate 440; lens 470; air cavity 480; projector 500; driving circuit 510; modulation circuit 520; DMD light modulator 530; projection lens 540; projection surface 600; illumination light L1; image light L2. DETAILED DESCRIPTION

[0014] In order to enable those skilled in the art to better understand the technical solution of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described implementation methods are only part of the implementation methods of the present application, rather than all the implementation methods. Based on the implementation methods in the present application, all other implementation methods obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0015] The inventors found that the current density in the second contact hole of the light-emitting diode is not less than 3A / mm 2When the light-emitting diode is switched on and off, carriers are likely to accumulate on both sides of the light-emitting layer, forming a diffusion capacitor. At this time, switching the light-emitting diode back and forth will cause the carrier concentration to change back and forth, causing the diffusion capacitor to oscillate. The oscillation of the diffusion capacitor will cause the light-emitting diode to resonate and produce a whistling noise.

[0016] Therefore, how to make the current density in the second contact hole of the light-emitting diode not less than 3A / mm 2 When the noise generated by the light emitting diode is suppressed, it is still a technical problem that the technicians in this field need to solve urgently. In order to solve the above technical problem, the inventors of this application have proposed the following embodiments after research.

[0017] Example 1 like Figure 1-Figure 5 As shown, the method for preparing the light emitting diode 10 of the present application includes steps 100 to S200.

[0018] Step S100: providing a diode body 100 .

[0019] like Figure 1-Figure 4 As shown, the diode body 100 includes a second electrode layer 110 , a first insulating layer 120 , and an epitaxial stack 130 in order from bottom to top.

[0020] The first insulating layer 120 is provided with a plurality of second contact holes 121 penetrating the second semiconductor layer 131 and the light emitting layer 132 and extending to the first semiconductor layer 133 , and the second electrode layer 110 is electrically connected to the first semiconductor layer 133 through the second contact holes 121 .

[0021] Step S200 : Covering the diode body 100 with a flexible film 200 , wherein the flexible film 200 is disposed on the first semiconductor layer 133 , and the thickness of the flexible film 200 is a first thickness h1 , and the first thickness h1 is not greater than 10 μm.

[0022] like Figure 5 As shown, in one example, a flexible film 200 may be provided first, and the provided flexible film 200 may be covered on the diode body 100. In another example, the covered flexible film 200 may be formed on the diode body 100 by dispensing with a dispensing head.

[0023] The above method has at least the following two beneficial effects. First, the first thickness h1 being no greater than 10 μm is conducive to the overall thinness of the light-emitting diode 10, and further facilitates the heat dissipation of the light-emitting diode 10, so that the current density of the light-emitting diode 10 in the second contact hole 121 is no less than 3A / mm 2 Even not less than 6A / mm 2Secondly, since the flexible film 200 is disposed on the first semiconductor layer 133, when the light emitting diode 10 is switched back and forth under the control of the switch signal, the flexible film 200 can suppress the resonance between the diode body 100 and the diffusion capacitor, thereby suppressing the light emitting diode 10 from generating noise.

[0024] That is, the current density of the light emitting diode 10 in the second contact hole 121 is not less than 3A / mm 2 Even not less than 6A / mm 2 When the power is turned on, it can effectively suppress the generation of noise.

[0025] It should be noted that in addition to the above beneficial effects, the above method also has the following beneficial effects: Thirdly, the first thickness h1 is not greater than 10 μm, which is conducive to the light emitted by the light emitting layer 132 passing through the flexible film 200 , thereby facilitating the improvement of the light output brightness of the light emitting diode 10 .

[0026] It should be noted that the principle of the flexible film 200 suppressing the noise generated by the light-emitting diode 10 is to suppress the vibration of the light-emitting diode 10, including the following two points. The first point is that the flexible film 200 and the diode body 100 are glued together to form a whole, which allows part of the kinetic energy of the vibration of the diode body 100 to be transferred to the flexible film 200 to cause the vibration of the flexible film 200, thereby reducing the amplitude of the diode body 100. The second point is that the flexible film 200 is a flexible object with a damping effect. The flexible film 200 reciprocates and flexibly deforms during the vibration process, which will convert the kinetic energy of the vibration of the flexible film 200 into heat energy more quickly.

[0027] Alternatively, if Figure 5 As shown, the first thickness h1 may be 1-10 μm. The first thickness h1 is, for example, 1 μm, 3 μm or 10 μm.

[0028] It should be noted that if the first thickness h1 is too thick, the heat dissipation performance of the light emitting diode 10 will be reduced. If the first thickness h1 is too thin, the noise suppression performance of the flexible film 200 will be reduced. In order to take into account both the heat dissipation performance of the light emitting diode 10 and the noise suppression performance of the flexible film 200, the first thickness h1 can be 3-4 μm.

[0029] Alternatively, if Figure 1-Figure 5 As shown, the area of ​​the horizontal projection of the first semiconductor layer 133 is the first area S1. The overlapping area of ​​the horizontal projection of the flexible film 200 and the horizontal projection of the first semiconductor layer 133 is the fourth area S4. The ratio of the fourth area S4 to the first area S1 is a second ratio, and the second ratio is not less than 90%. In this way, the overlapping area of ​​the flexible film 200 and the first semiconductor layer 133 is large enough, so that the flexible film 200 can have a good suppression effect on the vibration of the diode body 100.

[0030] Optionally, in some examples, in order to improve the stability of the connection structure between the flexible film 200 and the epitaxial stack 130, so as to facilitate the transmission of the kinetic energy of vibration on the diode body 100 to the flexible film 200, the flexible film 200 covers the side of the first semiconductor layer 133 away from the light emitting layer 132, and the flexible film 133 extends to cover at least part of the side wall of the epitaxial stack 130. Further, the flexible film 200 may be a flexible adhesive film, but is not limited thereto.

[0031] Alternatively, if Figure 1-Figure 5 As shown, the horizontal projection area of ​​the first semiconductor layer 133 is the first area S1. The sum of the horizontal projection areas of all second contact holes 121 is the second area. The ratio of the second area to the first area S1 is a first ratio, which is not greater than 10%.

[0032] For ease of understanding, the area of ​​the horizontal projection of a single second contact hole 121 is defined as the third area S3, and the second area is the sum of the third areas S3 of all second contact holes 121. It should be noted that the horizontal projection of each structure in the diode body 100 refers to the orthographic projection of the corresponding structure in the diode body 100 on the horizontal plane when the stacking direction of the first semiconductor layer 133 and the light emitting layer 132 is perpendicular to the horizontal plane.

[0033] In the above manner, since the first ratio is not greater than 10%, the current density in the second contact hole 121 of the light emitting diode 10 can more easily reach 3A / mm 2 Above 6A / mm 2 above.

[0034] Alternatively, if Figure 1-Figure 5 As shown, the resonance frequency of the diffusion capacitance formed by the accumulation of carriers on both sides of the light-emitting layer 132 in the diode body 100 is the first natural frequency. The natural frequency of the diode body 100 is the second natural frequency, and the natural frequency of the light-emitting diode 10 is the third natural frequency.

[0035] The absolute value of the difference between the second natural frequency and the first natural frequency is the first absolute value. The absolute value of the difference between the third natural frequency and the first natural frequency is the second absolute value. The flexible film 200 is used to make the second absolute value greater than the first absolute value.

[0036] In the above manner, the second absolute value can be adjusted by using the flexible film 200 so that the second absolute value is greater than the first absolute value, thereby suppressing the resonance between the diode body 100 and the diffused capacitor. Optionally, in order to effectively suppress the resonance between the diode body 100 and the diffused capacitor, the difference between the second absolute value and the first absolute value is not less than a predetermined difference. By way of example and not limitation, the predetermined difference may be 5% of the second natural frequency, but is not limited thereto. In other embodiments, the predetermined difference may be reasonably set as needed.

[0037] Furthermore, if Figure 1-Figure 5 As shown, the distance between two adjacent second contact holes 121 is a first distance d1, and the first distance d1 is 50-200 μm. In this way, the current density in the second contact hole 121 of the light-emitting diode 10 can reach 3A / mm 2 above.

[0038] Optionally, the step of covering the diode body 100 with the provided flexible film 200 may include steps S210 to S220 .

[0039] Step S210 : applying glue to the corresponding position of the diode body 100 that needs to be covered with the flexible film 200 , and covering the flexible film 200 on the glue-applied area of ​​the diode body 100 .

[0040] Step S220 : baking the combined structure of the flexible film 200 and the diode body 100 to fix the flexible film 200 and the diode body 100 .

[0041] Alternatively, if Figure 1-Figure 5 As shown, the thickness of the epitaxial stack 130 is the second thickness h2, and the second thickness h2 is not greater than 10 μm, which has at least three beneficial effects. First, it is conducive to the light passing through the epitaxial stack 130, reducing the light loss of the light emitted by the light-emitting layer 132 in the process of passing through the epitaxial stack 130, thereby facilitating the improvement of the light output brightness of the light-emitting diode 10. Second, it is conducive to the overall light-weighting of the light-emitting diode 10, and further facilitates the heat dissipation of the light-emitting diode 10, so that the current density of the light-emitting diode 10 in the second contact hole 121 is not less than 3A / mm 2 Even not less than 6A / mm 2 In the third aspect, it is helpful to reduce the diffusion of current in the thickness direction perpendicular to the light-emitting layer 132, so that the current is more concentrated near the second contact hole 121, thereby helping to increase the current density near the second contact hole 121. Preferably, the second thickness h2 is 2 to 5 μm. For example, the second thickness h2 is 2 μm, 3 μm or 5 μm.

[0042] Example 2 See also Figure 1-Figure 5As shown, Example 2 is obtained by further limiting Example 1, and the parts of Example 2 that are the same as Example 1 are not repeated here. The further limitations in Example 2 are as follows.

[0043] Optionally, see Figure 1-Figure 5 As shown, the light emitted by the recombination of carriers in the light emitting layer 132 is one of red, green and blue light, but is not limited thereto.

[0044] Optionally, see Figure 1-Figure 5 As shown, in order to reduce the influence of the flexible film 200 on the inherent color and brightness of the light emitted from the diode body 100, the flexible film 200 may be a colorless film, but is not limited thereto.

[0045] Optionally, see Figure 1-Figure 5 As shown, in order to reduce the influence of the flexible film 200 on the light emitting angle of the light emitted from the diode body 100 , the thickness of the flexible film 200 may be uniformly distributed.

[0046] Preferably, see Figure 1-Figure 5 As shown, the flexible film 200 can be a colorless film, and the thickness of the flexible film 200 can be uniformly distributed. In this way, the flexible film 200 has the following first and second characteristics. The first characteristic includes that the flexible film 200 has little effect on the color of the light emitted from the diode body 100, and the light emitted from the diode body 100 will basically not change color after passing through the flexible film 200. The second characteristic includes that the flexible film 200 has little effect on the brightness and light output angle of the diode body 100, and the light emitted from the diode body 100 will basically not change significantly after passing through the flexible film 200.

[0047] In the above manner, since the flexible film 200 has the first and second characteristics, the diode body 100 that has been produced and tested for light emission performance before being covered with the flexible film 200 does not need to be retested for light emission performance after being covered with the flexible film 200. Therefore, the flexible film 200 can be used in various types of diode bodies 100 produced on the same platform.

[0048] Optionally, see Figure 1-Figure 5 As shown, in one example, the flexible film 200 may be a single-layer structure formed by one of silicone and epoxy resin, but is not limited thereto. Alternatively, in another example, the flexible film 200 may be a multi-layer structure formed by stacking multiple layers of silicone and epoxy resin, but is not limited thereto.

[0049] Example 3 See also Figure 1-Figure 5 As shown, Example 3 is obtained by further limiting Example 1, and the parts of Example 3 that are the same as Example 1 are not repeated here. The further limitations in Example 3 are as follows.

[0050] Optionally, the flexible film 200 may be a transparent film layer, such as a colorless film layer or a colored film layer.

[0051] In one example, see Figure 1-Figure 5 As shown, the flexible film 200 may be a single-layer structure formed of one of silica gel, epoxy resin and phosphor, but is not limited thereto. Figure 1-Figure 5 As shown, the flexible film 200 may be a multi-layer structure formed by stacking multiple layers of silica gel, epoxy resin and phosphor, but is not limited thereto.

[0052] Example 4 See also Figure 1-Figure 5 As shown, Example 4 is a further limitation on any one of Examples 1 to 3, and the same parts as in Examples 1 to 3 are not repeated here. Optionally, the further limitation in Example 4 is as follows.

[0053] See also Figure 1-Figure 5 As shown, the diode body 100 has a first region A and a second region B along a stacking direction perpendicular to the epitaxial stack 130 , and the second region B is located outside the first region A.

[0054] The diode body 100 includes a current spreading layer 140, a second insulating layer 150 and a first electrode 160. The current spreading layer 140 and the second insulating layer 150 are located between the first insulating layer 120 and the second semiconductor layer 131. The second electrode layer 110, the first insulating layer 120, the current spreading layer 140 and the second insulating layer 150 are continuously distributed in the first region A and the second region B. The epitaxial stack 130 is distributed in the first region A avoiding the second region B.

[0055] The second insulating layer 150 is located on the side of the current spreading layer 140 facing the second semiconductor layer 131, and the second insulating layer 150 is provided with a plurality of first openings 151 and a plurality of first contact holes 152. The first openings 151 are located in the first region A, and the current spreading layer 140 is electrically connected to the second semiconductor layer 131 through the first openings 151. The first contact holes 152 are located in the second region B, and the first electrode 160 is electrically connected to the current spreading layer 140 through the first contact holes 152.

[0056] By means of the above method, the diode body 100 can be formed into a vertical structure, which is conducive to the current density in the second contact hole 121 of the diode body 100 reaching 3A / mm 2 above.

[0057] Optionally, see Figure 1-Figure 5As shown, the diode body 100 includes an ohmic contact layer 170, which is located between the current spreading layer 140 and the second insulating layer 150. The ohmic contact layer 170 covers the second semiconductor layer 131 and is distributed around the second contact hole 121. The ohmic contact layer 170 is electrically connected to the second semiconductor layer 131, and the current spreading layer 140 is electrically connected to the ohmic contact layer 170 through the second contact hole 121.

[0058] Optionally, see Figure 1-Figure 5 As shown, the diode body 100 includes a conductive substrate 190 , and the second electrode layer 110 is electrically connected to the conductive substrate 190 through a bonding metal layer 180 .

[0059] Optionally, see Figure 1-Figure 5 As shown, the diode body 100 includes a passivation protection layer 191 covering the first semiconductor layer 133 in the first region A, the sidewall of the epitaxial stack 130 in the first region A, and the second insulating layer 150 exposed in the second region B. Optionally, the flexible film 200 covers the portion of the passivation protection layer 191 located in the first region A, but is not limited thereto.

[0060] Example 5 Combination Figure 1-Figure 5 , see Figure 6-Figure 13 As shown, Example 5 is a further limitation on any one of Examples 1 to 4, and the same parts of Example 4 as those of Examples 1 to 4 are not repeated here. Optionally, the further limitation in Example 4 is as follows.

[0061] Combination Figure 1-Figure 5 , see Figure 6-Figure 13 As shown, step S100 further includes steps S110 to S170.

[0062] Combination Figure 1-Figure 5 , see Figure 6 As shown, step S110: forming an epitaxial stack 130 , an ohmic contact layer 170 and a second insulating layer 150 in sequence on a growth substrate 300 .

[0063] The epitaxial stack 130 includes a first semiconductor layer 133, a light emitting layer 132, and a second semiconductor layer 131 in order from bottom to top. The epitaxial stack 130 is continuously distributed in the first region A and the second region B. The portion of the epitaxial stack 130 located in the first region A is provided with a plurality of second openings 134, and the second openings 134 pass through the second semiconductor layer 131 and the light emitting layer 132 to expose the first semiconductor layer 133. The ohmic contact layer 170 is located in the first region A and covers the second semiconductor layer 131 to be electrically connected to the second semiconductor layer 131. The second insulating layer 150 is continuously distributed in the first region A and the second region B and covers the ohmic contact layer 170. The region of the second insulating layer 150 covering the ohmic contact layer 170 is provided with a plurality of first openings 151, and the portion of the second insulating layer 150 corresponding to the second openings 134 exposes the first semiconductor layer 133.

[0064] Optionally, the first semiconductor layer 133 may be an N-type doped semiconductor layer, which may refer to the relevant records of the prior art and will not be described in detail here. The second semiconductor layer 131 may be a P-type doped semiconductor layer, which may refer to the relevant records of the prior art and will not be described in detail here. Optionally, the second electrode layer 110 may be an N-electrode, and the first electrode 160 may be a P-electrode, but is not limited thereto.

[0065] Combination Figure 1-Figure 5 , see Figure 7 As shown, step S120: forming a current spreading layer 140 , a first insulating layer 120 , a second electrode layer 110 and a first bonding layer 181 in sequence on the second insulating layer 150 .

[0066] The current spreading layer 140 covers the second insulating layer 150 and is continuously distributed in the first region A and the second region B. The current spreading layer 140 is electrically connected to the ohmic contact layer 170 through the first opening 151, and the portion of the current spreading layer 140 corresponding to the second opening 134 exposes the first semiconductor layer 133. The portion of the first insulating layer 120 corresponding to the second opening 134 is provided with a second contact hole 121 extending through the second semiconductor layer 131 and the light emitting layer 132 to the first semiconductor layer 133. The second electrode layer 110 is continuously distributed in the first region A and the second region B, and extends into the second contact hole 121 to be electrically connected to the first semiconductor layer 133. The first bonding layer 181 covers the second electrode layer 110.

[0067] For the description of the second contact hole 121 , the epitaxial stack 130 , the first area S1 , and the second area, reference may be made to the relevant description in the above-mentioned embodiment 1, which will not be repeated here.

[0068] Combination Figure 1-Figure 5 , see Figure 8-Figure 9As shown, step S130: bonding the first bonding layer 181 and the second bonding layer 182 to form a bonding metal layer 180 , wherein the second bonding layer 182 covers the conductive substrate 190 .

[0069] A conductive substrate 190 and a second bonding layer 182 are provided, and the second bonding layer 182 covers the conductive substrate 190. The first bonding layer 181 and the second bonding layer 182 are bonded to form a bonding metal layer 180.

[0070] Combination Figure 1-Figure 5 , see Figure 7-Figure 9 As shown, step S140: removing the growth substrate 300 on the side of the second insulating layer 150 facing away from the light emitting layer 132 .

[0071] contrast Figure 7 See also Fig. 9 , Fig. 9 The growth substrate 300 is removed.

[0072] Combination Figure 1-Figure 5 , see Fig.10 As shown, step S150: etching away the epitaxial stack 130 in the second region B to expose the second insulating layer 150 in the second region B.

[0073] After the epitaxial stack 130 in the second region B is etched away, the epitaxial stack 130 in the first region A is formed into a protruding light-emitting region pattern relative to the second region B. Fig.10 In the structure shown, a portion of the second insulating layer 150 located in the second region B is exposed.

[0074] Combination Figure 1-Figure 5 , see Fig.11 As shown, step S160 : etching a local area of ​​the second insulating layer 150 located in the second area B to form a first contact hole 152 exposing the current spreading layer 140 .

[0075] like Fig.11 As shown, a local area of ​​the second insulating layer 150 located in the second region B is etched to form a first contact hole 152 exposing the current spreading layer 140 .

[0076] Combination Figure 1-Figure 5 , see Fig.12 As shown, step S170 : preparing a first electrode 160 in the second region B, the first electrode 160 being electrically connected to the exposed current spreading layer 140 .

[0077] like Fig.12 As shown, a first electrode 160 is prepared in the second region B, and the first electrode 160 is electrically connected to the exposed current spreading layer 140 .

[0078] Combination Figure 1-Figure 5 , see Fig.13As shown, step S180: forming a passivation protection layer 191, the passivation protection layer 191 covers the first semiconductor layer 133 in the first region A, the side wall of the epitaxial stack 130 in the first region A and the second insulating layer 150 exposed in the second region B.

[0079] like Fig.13 As shown, the passivation protection layer 191 covers the first semiconductor layer 133 in the first region A, the sidewall of the epitaxial stack 130 in the first region A, and the second insulating layer 150 exposed in the second region B.

[0080] Experimental Group Combination Figure 1-Figure 5 , see Figure 14-15 As shown, a first light emitting diode 10a is provided, and the first light emitting diode 10a is the light emitting diode 10 of any one of the above-mentioned embodiments 1 to 5. The specific description of the first light emitting diode 10a can refer to the contents of the above-mentioned embodiments 1 to 5, and will not be repeated here.

[0081] It should be understood that Fig.15 The upper layer of the flexible film 200 is epoxy resin used to fix the first light emitting diode 10a during slicing. Fig.15 The epoxy resin layer on the flexible film 200 itself is not a component of the first light emitting diode 10 a.

[0082] Control group Combination Figure 1-Figure 5 , see Figure 14-15 As shown, a second light-emitting diode (not shown) is provided. The similarities between the second light-emitting diode and the first light-emitting diode 10a are not repeated. The difference between the second light-emitting diode and the first light-emitting diode 10a is that the second light-emitting diode does not contain the flexible film 200, and the other structures are the same as the first light-emitting diode 10a.

[0083] Comparative analysis When the first light emitting diode 10a and the second light emitting diode are switched back and forth using the same switching signal, the audio waveform of the noise of the first light emitting diode 10a is detected, and the Fig.16 ; and the audio waveform of the noise of the second light-emitting diode is detected to obtain Fig.17 .

[0084] Combination Fig.14 , shown in the comparison Fig.16 and Fig.17 It can be seen that Fig.16 The width of the middle audio waveform in the vertical direction is significantly smaller than Fig.17The width of the audio waveform in the vertical direction. The smaller the width of the audio waveform, the smaller the noise. Obviously, the noise generated by the first light emitting diode 10a is significantly lower than the noise generated by the second light emitting diode.

[0085] When the first light emitting diode 10a and the second light emitting diode are switched back and forth using the same switching signal, and the flexible film 200 of the first light emitting diode 10a does not include phosphor, the energy density of the light output brightness of the first light emitting diode 10a is detected, and the energy density of the light output brightness of the second light emitting diode is detected, and the energy density of the light output brightness of the second light emitting diode is obtained. Fig.18 .

[0086] Combination Fig.14 , see Fig.18 As shown, the dotted line represents the energy density of the first light-emitting diode 10a of the experimental group, and the short dash line represents the energy density of the second light-emitting diode of the control group. It can be seen that when the light-emitting angle is not less than -90 degrees and less than -60 degrees, the energy density of the first light-emitting diode 10a is almost equal to the energy density of the second light-emitting diode. When the light-emitting angle is not less than -60 degrees and less than -10 degrees, the energy density of the first light-emitting diode 10a is slightly higher than the energy density of the second light-emitting diode. When the light-emitting angle is not less than -10 degrees and less than 45 degrees, the energy density of the first light-emitting diode 10a is almost equal to the energy density of the second light-emitting diode. When the light-emitting angle is not less than 45 degrees and less than 60 degrees, the energy density of the first light-emitting diode 10a is slightly higher than the energy density of the second light-emitting diode. When the light-emitting angle is not less than 60 degrees and not more than 90 degrees, the energy density of the first light-emitting diode 10a is almost equal to the energy density of the second light-emitting diode.

[0087] That is, the energy density of the first light emitting diode 10a is not much different from the energy density of the second light emitting diode.

[0088] Example 6 Combination Figure 1-Figure 5 , see Fig.19 The light emitting device 400 of the present application includes a packaging substrate 440, a lens 470, and a light emitting diode 10. The light emitting diode 10 is the light emitting diode 10 of any one of the above-mentioned embodiments 1 to 5. The side of the flexible film 200 facing away from the first semiconductor layer 133 faces the lens 470, and the light emitting diode 10 is used to emit illumination light L1; the lens 470 is used to transmit the illumination light L1 so that the illumination light L1 is emitted.

[0089] Example 7 Combination Fig.19 See also Fig. 20 The projector 500 of the present application includes a driving circuit 510 , a light emitting device 400 , a modulation circuit 520 and a DMD light modulator 530 .

[0090] The driving circuit 510 is used to output a periodic switching signal, and each period of the switching signal includes a first period and a second period. The light emitting device 400 is electrically connected to the driving circuit 510, and the light emitting device 400 is the light emitting device 400 of the above-mentioned embodiment 6. The switching signal is used to control the light emitting device 400 to maintain a lit state in the first period; the switching signal is used to control the light emitting device 400 to maintain an extinguished state in the second period.

[0091] The modulation circuit 520 is electrically connected to the driving circuit 510, and the switch signal is used to control the modulation circuit 520 to output the light modulation signal in the first period. The DMD light modulator 530 is electrically connected to the modulation circuit 520 and is used to receive the illumination light L1 emitted by the light emitting device 400; the light modulation signal is used to control the DMD light modulator 530 to convert the illumination light L1 into the image light L2 including the projection screen in the first period.

[0092] In the above manner, under the control of the switch signal, the light emitting device 400 switches periodically between the lighting state and the extinguishing state, which is essentially switching the light emitting diode 10 in the light emitting device 400 back and forth. At this time, since the light emitting device 400 is the light emitting device 400 of the above embodiment 6, which includes the light emitting diode 10 in embodiment 1, it has at least two effects.

[0093] First, the first thickness h1 is not greater than 10 μm, which is beneficial to the overall lightness and thinness of the light emitting diode 10, and further beneficial to the heat dissipation of the light emitting diode 10, so that the current density of the light emitting diode 10 in the second contact hole 121 is not less than 3A / mm 2 Even not less than 6A / mm 2 In addition, the flexible film 200 is disposed on the first semiconductor layer 133, so that when the light emitting diode 10 is switched back and forth under the control of the switch signal, the flexible film 200 can suppress the resonance between the diode body 100 and the diffusion capacitor, thereby suppressing the light emitting diode 10 from generating noise. That is, the current density of the light emitting diode 10 in the second contact hole 121 of the present application is not less than 3A / mm 2 When the power is turned on, it can effectively suppress the generation of noise.

[0094] It should be understood that the image light L2 is light including a projection picture, and when the image light L2 is projected onto the projection surface 600, the projection picture can be displayed on the projection surface 600. Optionally, the projector 500 may include a projection lens 540, which is disposed on the outgoing light path of the DMD light modulator 530 and is used to expand the image light L2 to enlarge the projection picture.

[0095] The above are only implementation methods of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A light emitting diode, characterized in that: The light emitting diode comprises a diode body and a flexible film in order from bottom to top, the diode body comprises a second electrode layer, a first insulating layer and an epitaxial stack in order from bottom to top; the epitaxial stack comprises a second semiconductor layer, a light emitting layer and a first semiconductor layer in order from bottom to top; The first insulating layer is provided with a plurality of second contact holes which pass through the second semiconductor layer and the light-emitting layer and extend to the first semiconductor layer, and the second electrode layer is electrically connected to the first semiconductor layer through the second contact holes; the flexible film is provided on the first semiconductor layer, and the thickness of the flexible film is a first thickness, and the first thickness is not greater than 10 μm.

2. The light emitting diode according to claim 1, characterized in that: The epitaxial stack has a second thickness, and the second thickness is no greater than 10 μm.

3. The light emitting diode according to claim 2, characterized in that: The first thickness is 1-10 μm.

4. The light emitting diode according to claim 1, characterized in that: The second thickness is 2-5 μm.

5. The light emitting diode according to claim 1, characterized in that: The horizontal projection area of ​​the first semiconductor layer is the first area; the sum of the horizontal projection areas of all the second contact holes is the second area; the ratio of the second area to the first area is a first ratio, and the first ratio is not greater than 10%.

6. The light emitting diode according to claim 5, characterized in that: The distance between two adjacent second contact holes is a first distance, and the first distance is 50-200 μm.

7. The light emitting diode according to claim 1, characterized in that: The area of ​​the horizontal projection of the first semiconductor layer is a first area; the overlapping area of ​​the horizontal projection of the flexible film and the horizontal projection of the first semiconductor layer is a fourth area; The ratio of the fourth area to the first area is a second ratio, and the second ratio is not less than 90%.

8. The light emitting diode according to claim 7, characterized in that: The flexible film covers a side of the first semiconductor layer facing away from the light emitting layer, and the flexible film extends to cover at least a portion of a side wall of the epitaxial stack.

9. The light emitting diode according to claim 1, characterized in that: The flexible film includes a single-layer structure formed by one of silicone and epoxy resin or a multi-layer structure formed by stacking multiple layers.

10. The light emitting diode according to claim 1, characterized in that: The resonant frequency of the diffusion capacitance formed in the diode body due to the accumulation of carriers on both sides of the light-emitting layer is the first natural frequency; the natural frequency of the diode body is the second natural frequency, and the natural frequency of the light-emitting diode is the third natural frequency; The absolute value of the difference between the second natural frequency and the first natural frequency is a first absolute value; the absolute value of the difference between the third natural frequency and the first natural frequency is a second absolute value; and the flexible membrane is used to make the second absolute value greater than the first absolute value.

11. The light emitting diode according to claim 1, characterized in that: The light emitted by the recombination of carriers in the light-emitting layer is one of red, green and blue light.

12. The light emitting diode according to claim 1, characterized in that: The diode body has a first region and a second region along a stacking direction perpendicular to the epitaxial stack, and the second region is located outside the first region; The diode body comprises a current spreading layer, a second insulating layer and a first electrode; the current spreading layer and the second insulating layer are located between the first insulating layer and the second semiconductor layer; the second electrode layer, the first insulating layer, the current spreading layer and the second insulating layer are continuously distributed in the first region and the second region; the epitaxial stack is distributed in the first region avoiding the second region; The second insulating layer is located on a side of the current spreading layer facing the second semiconductor layer, and the second insulating layer is provided with a plurality of first openings and a plurality of first contact holes; the first opening is located in the first region, and the current spreading layer is electrically connected to the second semiconductor layer through the first opening; the first contact hole is located in the second region, and the first electrode is electrically connected to the current spreading layer through the first contact hole.

13. A light emitting device, characterized in that: The light emitting device comprises: Package substrate; A lens is disposed on the packaging substrate and forms an air cavity with the packaging substrate; and a light emitting diode, wherein the light emitting diode is the light emitting diode according to any one of claims 1 to 12; the light emitting diode is disposed on the packaging substrate and is located in the air cavity; The side of the flexible film facing away from the first semiconductor layer faces the lens, the light emitting diode is used to emit illumination light, and the lens is used to transmit the illumination light so that the illumination light can be emitted.

14. A projector, characterized in that: The projector comprises: A driving circuit, configured to output a periodic switching signal, wherein each period of the switching signal includes a first time period and a second time period; And a light-emitting device electrically connected to the driving circuit, the light-emitting device is the light-emitting device according to claim 13; the switching signal is used to control the light-emitting device to maintain a lit state during the first time period; the switching signal is used to control the light-emitting device to maintain an unlit state during the second time period.

15. The projector according to claim 14, characterized in that The projector comprises: A modulation circuit, electrically connected to the driving circuit, wherein the switch signal is used to control the modulation circuit to output an optical modulation signal during the first period; and a DMD light modulator electrically connected to the modulation circuit and used for receiving the illumination light emitted by the light emitting device; the light modulation signal is used for controlling the DMD light modulator in the first time period to convert the illumination light into image light for projecting a picture.

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