Light-emitting device structure and preparation method thereof

Abstract

The invention provides a light-emitting device structure and a preparation method thereof, and the light-emitting device structure comprises a buffer layer which is made of a transparent material; the light-emitting structure is located on one side of the buffer layer, and the light-emitting structure is provided with at least one light-emitting unit; wherein the buffer layer is provided with at least one micro-lens structure, the micro-lens structure is provided with at least two sub-layers, and one light-emitting unit corresponds to the at least one micro-lens structure. The buffer layer made of the transparent material is utilized to manufacture the micro lens structure, on one hand, the total reflection problem is relieved, the light emitting efficiency of the light emitting device is improved, on the other hand, the micro lens structure does not need to be additionally manufactured, and the production cost is reduced.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor technology, and in particular to a light emitting device structure and a preparation method thereof. Background Art

[0002] Light Emitting Diode (LED) is used in various fields due to its advantages such as long life and low energy consumption. In particular, as its lighting performance is increasingly improved, LED is often used as a light-emitting device in the lighting field. Among them, III-V compound semiconductors represented by gallium nitride (GaN) have great application potential in the field of optoelectronic devices such as high-brightness light-emitting diodes and lasers due to their wide band gap, high electron saturation drift velocity, and stable chemical properties, which has attracted widespread attention.

[0003] However, the current semiconductor light emitting diodes have the problem of low light emitting efficiency. For ordinary unpackaged light emitting diodes, their light extraction efficiency is generally only a few percent, and a large amount of energy is accumulated inside the device and cannot be emitted, which not only causes energy waste, but also shortens the service life of the device. Therefore, it is very important to improve the light extraction efficiency of semiconductor light emitting diodes.

[0004] Based on the above application requirements, many methods to improve the light output efficiency of light-emitting diodes have been applied to the device structure, such as making a microlens structure on the surface of the LED. However, since the microlens is generally made of organic resin material, it is easy to deform at high temperature, resulting in a decrease in the stability of the LED optical performance. Summary of the invention

[0005] In view of this, the embodiments of the present disclosure provide a light-emitting device structure and a method for preparing the same to solve the problem that microlenses are easily deformed at high temperatures, improve the optical stability of the light-emitting device, and improve the light extraction efficiency of the light-emitting device.

[0006] According to one aspect of the present disclosure, an embodiment of the present disclosure provides a light emitting device structure, characterized in that it includes:

[0007] A buffer layer, wherein the buffer layer is made of a transparent material;

[0008] A light emitting structure, located on one side of the buffer layer, wherein the light emitting structure has at least one light emitting unit;

[0009] The buffer layer has at least one microlens structure, the microlens structure has at least two sublayers, and one of the light-emitting units corresponds to at least one of the microlens structures.

[0010] As an optional embodiment, the light-emitting structure is located on a focal plane of the microlens structure.

[0011] As an optional embodiment, the microlens structure includes a plurality of sublayers with different refractive indices.

[0012] As an optional embodiment, in the direction of the microlens structure pointed by the light-emitting structure, the refractive indices of the multiple sublayers of the microlens structure gradually decrease or first increase and then decrease, and the refractive indices of the multiple sublayers of the microlens structure change in a uniform, jumpy or step-like manner.

[0013] As an optional embodiment, the microlens structure includes multiple AlGaN sublayers with different Al components. In the direction from the light-emitting structure to the microlens structure, the Al component gradually decreases or first increases and then decreases. The Al component changes in a uniform, jumpy or step-like manner.

[0014] As an optional embodiment, the light-emitting units have the same size, one light-emitting unit corresponds to one microlens structure, and at least one microlens structure has a size different from that of the other microlens structures.

[0015] As an optional embodiment, the microlens structures have the same curvature radius, and at least one of the microlens structures has a thickness different from that of the other microlens structures.

[0016] As an optional embodiment, the microlens structures have the same thickness, and at least one of the microlens structures has a different radius of curvature from the other microlens structures.

[0017] As an optional embodiment, the number of the microlens structures corresponding to at least one of the light-emitting units is different from the number of the microlens structures corresponding to other light-emitting units.

[0018] As an optional embodiment, the microlens structure includes at least one of a spherical convex lens, an aspherical convex lens, a spherical concave lens and an aspherical concave lens.

[0019] As an optional embodiment, the material of the buffer layer includes at least one of AlN, GaN, AlGaN and AlInGaN.

[0020] As an optional embodiment, the light emitting device structure further comprises:

[0021] The substrate structure is located on a side of the buffer layer away from the light emitting structure. The substrate structure has at least one opening penetrating the substrate structure. One of the light emitting units corresponds to one of the openings.

[0022] As an optional embodiment, the light emitting device structure further comprises:

[0023] The AlN film is located on a surface of the microlens structure at a side away from the light emitting structure.

[0024] As an optional embodiment, the light emitting device structure further comprises:

[0025] A metal lens with a dielectric hole is located on a surface of the microlens structure that is away from the light-emitting structure.

[0026] As an optional embodiment, the microlens structure further comprises:

[0027] A first DBR layer is located at a side of the microlens structure close to the light emitting structure.

[0028] As an optional embodiment, the light emitting device structure further comprises:

[0029] A second DBR layer is located at a side of the light emitting structure away from the microlens structure.

[0030] According to another aspect of the present disclosure, an embodiment of the present disclosure provides a method for preparing a light emitting device structure, characterized in that it includes the following steps:

[0031] S1. providing a substrate;

[0032] S2, growing a buffer layer of a transparent material on the substrate;

[0033] S3, growing a light-emitting structure on the buffer layer, wherein the light-emitting structure has at least one light-emitting unit;

[0034] S4. Remove the substrate by etching from a side away from the buffer layer, and form at least one microlens structure by etching on a surface of the buffer layer away from the light-emitting structure. The microlens structure has at least two sublayers, and one light-emitting unit corresponds to at least one microlens structure.

[0035] As an optional embodiment, the etching of the substrate in the step S4 is patterned etching, and the retained substrate becomes a substrate structure, serving as a retaining wall between two adjacent light-emitting units.

[0036] As an optional embodiment, the light-emitting units have the same size, one light-emitting unit corresponds to one microlens structure, and at least one microlens structure has a size different from that of the other microlens structures.

[0037] As an optional embodiment, the number of the microlens structures corresponding to at least one of the light-emitting units is different from the number of the microlens structures corresponding to other light-emitting units.

[0038] The present disclosure provides a light-emitting device structure and a preparation method thereof, wherein the light-emitting device structure includes a buffer layer, which is made of a transparent material; a light-emitting structure, which is located on one side of the buffer layer, and has at least one light-emitting unit; wherein the buffer layer has at least one microlens structure, and the microlens structure has at least two sublayers, and one light-emitting unit corresponds to at least one microlens structure.

[0039] Beneficial effect 1: The microlens structure is designed so that when the light emitted by the light-emitting structure is emitted through the surface of the microlens structure, its incident angle is always smaller than the critical angle of total reflection, so that total reflection does not occur, ensuring that most of the light can be transmitted from the surface of the microlens structure, thereby improving the light extraction efficiency of the light-emitting device.

[0040] Beneficial effect 2: The microlens structure is made using a buffer layer, and there is no need to make an additional microlens structure. This can effectively reduce the device thickness, improve transmittance and reduce production costs. The microlens structure made of the buffer layer is not easy to deform at high temperatures, thereby improving the optical stability of the light-emitting device.

[0041] Beneficial effect 3: The microlens structure is designed using a multi-layer buffer layer. The microlens structure has multiple sub-layers with different refractive indices, which reduces the refractive index difference between the contact interface between the light-emitting structure and the microlens structure and the contact interface between the microlens structure and the air, further reduces the possibility of total reflection of light, improves the utilization rate of light, and thus improves the light extraction efficiency of the light-emitting device.

[0042] Beneficial effect 4: Microlens structures of different sizes are designed to correspond to the red, green and blue three-color lights, thereby improving the light output efficiency of the three-color lights while improving the light output uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Shown is a schematic diagram of the structure of a light-emitting device provided in one embodiment of the present disclosure.

[0044] Figure 2a to Figure 2d The figure shows the variation trend of the refractive index of multiple sub-layers of the micro-lens structure of the light-emitting device provided by an embodiment of the present disclosure.

[0045] Figure 3 Shown is a schematic diagram of the structure of a light-emitting device provided in one embodiment of the present disclosure.

[0046] Figure 4 Shown is a schematic diagram of the structure of a light-emitting device provided in one embodiment of the present disclosure.

[0047] Figure 5 Shown is a schematic diagram of the structure of a light-emitting device provided in one embodiment of the present disclosure.

[0048] Figure 6 Shown is a schematic diagram of the structure of a light-emitting device provided in one embodiment of the present disclosure.

[0049] Figure 7 Shown is a schematic diagram of the structure of a light-emitting device provided in one embodiment of the present disclosure.

[0050] Figure 8 Shown is a schematic diagram of the structure of a light-emitting device provided in one embodiment of the present disclosure.

[0051] Fig. 9 Shown is a schematic diagram of the structure of a light-emitting device provided in one embodiment of the present disclosure.

[0052] Fig.10 Shown is a flow chart of a method for preparing a light-emitting device structure provided in one embodiment of the present disclosure.

[0053] Figure 11-15 The figure shows a schematic diagram of the decomposition of the light-emitting device structure during the preparation process provided by an embodiment of the present disclosure.

[0054] Fig.16 Shown is a schematic diagram of the structure of a light-emitting device provided in one embodiment of the present disclosure. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0056] In order to solve the technical problem that the microlens structure on the surface of LED is easy to deform at high temperature in the prior art, the present disclosure provides a light-emitting device structure and a preparation method thereof, wherein the light-emitting device structure includes a buffer layer, the buffer layer is a transparent material; a light-emitting structure, located on one side of the buffer layer, the light-emitting structure has at least one light-emitting unit; wherein the buffer layer has at least one microlens structure, the microlens structure has at least two sublayers, and one light-emitting unit corresponds to at least one microlens structure. The present disclosure uses a buffer layer of transparent material to make a microlens structure, which, on the one hand, alleviates the total reflection problem, thereby improving the light extraction efficiency of the light-emitting device, and on the other hand, does not require additional microlens structure production, thereby reducing production costs.

[0057] Combine the following Figures 1 to 16 A light-emitting device structure and a method for preparing the same mentioned in the present disclosure are further illustrated by way of example.

[0058] Figure 1 FIG. 1 is a schematic diagram of the structure of a light emitting device provided by an embodiment of the present disclosure. Figure 1As shown, the light-emitting device structure includes: a buffer layer 20, which is a transparent material; a light-emitting structure 30, which is located on one side of the buffer layer 20, and the light-emitting structure 30 has at least one light-emitting unit; wherein the buffer layer 20 has at least one microlens structure 23, and the microlens structure 23 has at least two sub-layers, and one light-emitting unit corresponds to at least one microlens structure 23.

[0059] In this embodiment, the microlens structure 23 includes at least one of a spherical convex lens, an aspherical convex lens, a spherical concave lens, and an aspherical concave lens. The light emitting structure 30 is located on the focal plane of the microlens structure 23. The light emitting structure 30 is located on the focal plane of the microlens structure 23, so that the transmitted light is refracted to be parallel to each other and parallel to the central axis of the lens, the collimation is maximized, and thus the capture efficiency is maximized.

[0060] In this embodiment, the material of the buffer layer 20 includes at least one of AlN, GaN, AlGaN and AlInGaN. The microlens structure 23 is prepared by the buffer layer 20, so the material of the microlens structure 23 also includes at least one of AlN, GaN, AlGaN and AlInGaN. The microlens structure 23 is not easily deformed at high temperatures, thereby improving the optical stability of the light-emitting device.

[0061] In one embodiment, Figure 2a to Figure 2d The figure shows the variation trend of the refractive index of multiple sub-layers of the micro-lens structure of the light-emitting device provided by an embodiment of the present disclosure. The micro-lens structure 23 includes multiple sub-layers with different refractive indices. From the direction of the light-emitting structure 30 pointing to the micro-lens structure 23, the refractive index of the multiple sub-layers of the micro-lens structure 23 gradually decreases (e.g. Figure 2a as shown) or increases first and then decreases (as shown Figure 2b As shown), the refractive index of the multiple sub-layers of the microlens structure 23 changes in a uniform manner (as shown Figure 2a As shown), jump changes (such as Figure 2c as shown) or step-like changes (as shown Figure 2d The main reason for the low light extraction efficiency is that the refractive index difference between the light emitting structure and the air is large. By designing a microlens structure 23 having a plurality of sub-layers with different refractive indices, the refractive index difference between the contact interface between the light emitting structure 30 and the microlens structure 23 and the contact interface between the microlens structure 23 and the air is reduced, thereby reducing the possibility of total reflection of light, improving the utilization rate of light, and improving the light extraction efficiency of the light emitting device.

[0062] In one embodiment, the microlens structure 23 includes a plurality of AlGaN sublayers with different Al components. In the direction from the light emitting structure 30 to the microlens structure 23, the Al component gradually decreases or increases first and then decreases. The Al component changes in a uniform, jumpy, or step-like manner. The Al component in the AlGaN material has the same change trend as the refractive index. Increasing the Al component can increase the refractive index of the AlGaN material.

[0063] In one embodiment, the light emitting units have the same size, one light emitting unit corresponds to one microlens structure 23 , and at least one microlens structure 23 has a size different from that of other microlens structures 23 . Figure 3 FIG. 1 is a schematic diagram of the structure of a light emitting device provided by an embodiment of the present disclosure. Figure 3 As shown, the microlens structures 23 have the same radius of curvature, and at least one microlens structure 23 has a thickness different from that of other microlens structures 23. Specifically, when the colors of the light emitted by each light-emitting unit of the light-emitting structure 30 include red light, green light, and blue light, the frequency of red light is lower and the refractive index in the medium is smaller. Since the larger the refractive index, the shorter the focal length, the focal length of red light is the longest. In order to make the light-emitting units emitting red light, green light, and blue light all on the focal plane of the microlens structure 23, the thickness of the microlens structure 23 corresponding to red light can be designed to be the largest, the thickness of the microlens structure 23 corresponding to green light can be centered, and the thickness of the microlens structure 23 corresponding to blue light can be designed to be the smallest. Figure 4 FIG. 1 is a schematic diagram of the structure of a light emitting device provided by an embodiment of the present disclosure. Figure 4 As shown, the thickness of the microlens structure 23 is the same, and at least one microlens structure 23 has a different radius of curvature from other microlens structures 23. Specifically, when the colors of the light emitted by each light-emitting unit of the light-emitting structure 30 include red light, green light, and blue light, the focal length of red light is the longest. Since the larger the radius of curvature of the lens, the larger the focal length, the focal length of red light can be reduced by reducing the radius of curvature of the microlens structure 23 corresponding to red light. In order to make the light-emitting units emitting red light, green light, and blue light all on the focal plane of the microlens structure 23, the radius of curvature of the microlens structure 23 corresponding to red light can be designed to be the smallest, the radius of curvature of the microlens structure 23 corresponding to green light to be in the middle, and the radius of curvature of the microlens structure 23 corresponding to blue light to be the largest.

[0064] In one embodiment, Figure 5 FIG. 1 is a schematic diagram of the structure of a light emitting device provided by an embodiment of the present disclosure. Figure 5 As shown, the number of microlens structures 23 corresponding to at least one light-emitting unit is different from the number of microlens structures 23 corresponding to other light-emitting units. The sizes of the light-emitting units can be the same or different. By designing different numbers of microlens structures 23 corresponding to one light-emitting unit, the size of the microlens structure 23 can be changed.

[0065] In one embodiment, Figure 6 FIG. 1 is a schematic diagram of the structure of a light emitting device provided by an embodiment of the present disclosure. Figure 6 As shown, the light emitting device structure further includes: a substrate structure 11, which is located on a side of the buffer layer 20 away from the light emitting structure 30, and the substrate structure 11 has at least one opening 12 that penetrates the substrate structure 11, and one light emitting unit corresponds to one opening 12. The material of the substrate structure 11 includes silicon, which can serve as a barrier between two adjacent light emitting units to avoid light crosstalk.

[0066] In one embodiment, Figure 7 FIG. 1 is a schematic diagram of the structure of a light emitting device provided by an embodiment of the present disclosure. Figure 7 As shown, the light emitting device structure further includes: an AlN film 24, which is located on the surface of the microlens structure 23 away from the light emitting structure 30. The AlN film 24 has an anti-reflection film function, and the preparation method includes metal organic chemical vapor deposition or physical vapor deposition. By setting the AlN film 24, the reflection of light is further reduced to increase the transmittance and improve the light extraction efficiency.

[0067] In one embodiment, Figure 8 FIG. 1 is a schematic diagram of the structure of a light emitting device provided by an embodiment of the present disclosure. Figure 8 As shown, the light emitting device structure further includes: a metal lens 25 with a dielectric hole, which is located on the surface of the microlens structure 23 away from the light emitting structure 30. The dielectric hole is filled with a high refractive index dielectric material and an anti-reflection film material, and the shape of the dielectric hole can include at least one of a circle, a triangle, a rectangle and a hexagon, which is not specifically limited in the present disclosure. By providing the metal lens 25 with a dielectric hole, the light output direction is adjusted and the light output efficiency is improved.

[0068] In one embodiment, Fig. 9 FIG. 1 is a schematic diagram of the structure of a light emitting device provided by an embodiment of the present disclosure. Fig. 9 As shown, the microlens structure 23 further includes: a first DBR layer 51, and the first DBR layer 51 is located on the side of the microlens structure 23 close to the light-emitting structure 30. The first DBR layer 51 is also prepared using a multi-sublayer buffer layer 20. The DBR structure and the microlens structure are prepared simultaneously through the buffer layer 20, which simplifies the process and saves costs. The light-emitting device structure further includes: a second DBR layer 52, and the second DBR layer 52 is located on the side of the light-emitting structure 30 away from the microlens structure 23. The reflectivity of the second DBR layer 52 is greater than the reflectivity of the first DBR layer 51, and the light emitted by the light-emitting structure 30 is emitted through the first DBR layer 51 on the surface of the microlens structure 23 away from the light-emitting structure 30. The material of the first DBR layer 51 can be a III-V semiconductor material. The second DBR layer 52 can be a Bragg reflector, and the material is selected from the group consisting of TiO 2 / SiO2 、Ti 3 O 5 / SiO 2 、 2 O 5 / SiO 2 、Ti 3 O 5 / Al 2 O 3 、ZrO 2 / SiO 2 or TiO 2 / Al 2 O 3 A set of multi-periodic materials in the same material group, but the embodiments of the present disclosure are not limited thereto.

[0069] According to another aspect of the present disclosure, Fig.10 FIG. 1 is a flow chart of a method for preparing a light emitting device structure according to an embodiment of the present disclosure. Figure 11-15 FIG. 1 is a schematic diagram of the decomposition of the light emitting device structure provided in an embodiment of the present disclosure during the preparation process. Fig.10 As shown, a method for preparing a light-emitting device structure provided by an embodiment of the present disclosure includes the following steps:

[0070] Step S1: Fig.11 As shown, a substrate 10 is provided. The material of the substrate 10 includes silicon.

[0071] Step S2: Fig.12 As shown, a buffer layer 20 of a transparent material is grown on a substrate 10. The material of the buffer layer 20 includes at least one of AlN, GaN, AlGaN and AlInGaN.

[0072] Step S3: Fig.13 As shown, a light emitting structure 30 is grown on the buffer layer 20, and the light emitting structure 30 has at least one light emitting unit. The light emitting structure 30 includes: a first semiconductor layer 31, an active layer 32, a second semiconductor layer 33, an insulating structure 34, and at least one group of first electrodes 35 and second electrodes 36; the first electrode 35 is connected to the first semiconductor layer 31, the second electrode 36 is connected to the second semiconductor layer 33, the first electrode 35 and the second electrode 36 are blocked by an insulating material 37, and two adjacent light emitting units are blocked by the insulating structure 34.

[0073] Step S4: Fig.14 As shown, the substrate 10 is removed by etching from the side away from the buffer layer 20 , and at least one microlens structure 23 is formed by etching on the surface of the buffer layer 20 away from the light emitting structure 30 . The microlens structure 23 has at least two sublayers, and one light emitting unit corresponds to at least one microlens structure 23 .

[0074] In one embodiment, Fig.15 As shown, the etching of the substrate 10 in step S4 is patterned etching, and the retained substrate 10 becomes a substrate structure 11, which serves as a retaining wall between two adjacent light-emitting units. The substrate structure 11 is located on the side of the buffer layer 20 away from the light-emitting structure 30. The substrate structure 11 has at least one opening 12 that penetrates the substrate structure 11. One light-emitting unit corresponds to one opening 12. The surface of the buffer layer 20 exposed by the opening 12 is etched to form a microlens structure 23. The material of the substrate structure 11 includes silicon, which serves as a retaining wall between two adjacent light-emitting units to avoid light crosstalk.

[0075] In one embodiment, the light emitting units have the same size, one light emitting unit corresponds to one microlens structure 23, and at least one microlens structure 23 has a size different from that of other microlens structures 23. Figure 3 As shown, the microlens structures 23 have the same radius of curvature, at least one microlens structure 23 has a thickness different from that of the other microlens structures 23, or as shown in FIG. Figure 4 As shown, the thickness of the microlens structures 23 is the same, and at least one microlens structure 23 has a different radius of curvature from the other microlens structures 23. The sizes of the microlens structures 23 corresponding to the light-emitting units emitting red light, green light, and blue light are changed by etching, so that the light-emitting units emitting red light, green light, and blue light can all be located on the focal plane of the microlens structure 23, so that the transmitted light of various colors can be refracted to be parallel to each other and parallel to the central axis of the lens, the collimation is maximized, and thus the capture efficiency is maximized.

[0076] In one embodiment, etching can make the number of microlens structures 23 corresponding to at least one light-emitting unit different from the number of microlens structures 23 corresponding to other light-emitting units. The sizes of the light-emitting units can be the same or different. By etching different numbers of microlens structures 23 in the buffer layer 20 corresponding to one light-emitting unit, the size of the microlens structure 23 can be changed.

[0077] In one embodiment, Fig.16 The figure shows a schematic diagram of the structure of a light-emitting device provided by an embodiment of the present disclosure. A groove is dug on the side of the light-emitting structure 30 away from the microlens structure 23, the groove completely penetrates the second semiconductor layer 33 and the active layer 32, and partially penetrates the first semiconductor layer 31, a first electrode 35 is prepared in the groove, the first electrode 35 is insulated and blocked from the second semiconductor layer 33 and the active layer 32 by an insulating material 37, the first electrode 35 is connected to the first semiconductor layer 31, and a second electrode 36 is made on the side of the second semiconductor layer 33 away from the active layer 32, the second electrode 36 is insulated and blocked from the first electrode 35, and a structure as shown in FIG. Figure 1The light-emitting device structure shown in FIG. 1 can also be formed by digging a groove on one side of the light-emitting structure 30 close to the microlens structure 23, wherein the groove completely penetrates the buffer layer 20 and partially penetrates the first semiconductor layer 31, and a first electrode 35 is prepared in the groove, and the first electrode 35 is insulated and blocked from the buffer layer 20 by an insulating material 37, and a second electrode 36 is formed on the side of the second semiconductor layer 33 away from the active layer 32, so as to form a light-emitting device structure shown in FIG. Fig.16 The light emitting device structure shown.

[0078] The present disclosure provides a light-emitting device structure and a preparation method thereof, wherein the light-emitting device structure includes a buffer layer, which is made of a transparent material; a light-emitting structure, which is located on one side of the buffer layer, and has at least one light-emitting unit; wherein the buffer layer has at least one microlens structure, and the microlens structure has at least two sublayers, and one light-emitting unit corresponds to at least one microlens structure.

[0079] Beneficial effect 1: The microlens structure is designed so that when the light emitted by the light-emitting structure is emitted through the surface of the microlens structure, its incident angle is always smaller than the critical angle of total reflection, so that total reflection does not occur, ensuring that most of the light can be transmitted from the surface of the microlens structure, thereby improving the light extraction efficiency of the light-emitting device.

[0080] Beneficial effect 2: The microlens structure is made using a buffer layer, and there is no need to make an additional microlens structure. This can effectively reduce the device thickness, improve transmittance and reduce production costs. The microlens structure made of the buffer layer is not easy to deform at high temperatures, thereby improving the optical stability of the light-emitting device.

[0081] Beneficial effect 3: The microlens structure is designed using a multi-layer buffer layer. The microlens structure has multiple sub-layers with different refractive indices, which reduces the refractive index difference between the contact interface between the light-emitting structure and the microlens structure and the contact interface between the microlens structure and the air, further reduces the possibility of total reflection of light, improves the utilization rate of light, and thus improves the light extraction efficiency of the light-emitting device.

[0082] Beneficial effect 4: Microlens structures of different sizes are designed to correspond to the red, green and blue three-color lights, thereby improving the light output efficiency of the three-color lights while improving the light output uniformity.

[0083] It should be understood that the term "including" and its variations used in the present disclosure are open inclusions, that is, "including but not limited to". The term "one embodiment" means "at least one embodiment". In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0084] The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A light emitting device structure, characterized in that: include: A buffer layer (20), wherein the buffer layer (20) is made of a transparent material; A light emitting structure (30), located on one side of the buffer layer (20), the light emitting structure (30) having at least one light emitting unit; The buffer layer (20) has at least one microlens structure (23), the microlens structure (23) has at least two sublayers, and one of the light-emitting units corresponds to at least one of the microlens structures (23).

2. The light emitting device structure according to claim 1, characterized in that: The light emitting structure (30) is located on the focal plane of the microlens structure (23).

3. The light emitting device structure according to claim 1, characterized in that: The microlens structure (23) comprises a plurality of sublayers with different refractive indices.

4. The light emitting device structure according to claim 3, characterized in that: In the direction from the light emitting structure (30) to the microlens structure (23), the refractive index of the multiple sublayers of the microlens structure (23) gradually decreases or first increases and then decreases, and the refractive index of the multiple sublayers of the microlens structure (23) changes in a uniform, jumpy or step-like manner.

5. The light emitting device structure according to claim 3, characterized in that: The microlens structure (23) comprises a plurality of AlGaN sublayers with different Al components, and in the direction from the light-emitting structure (30) to the microlens structure (23), the Al component gradually decreases or first increases and then decreases, and the Al component changes in a uniform, jumpy or step-like manner.

6. The light emitting device structure according to claim 1, characterized in that: The light-emitting units have the same size, one light-emitting unit corresponds to one microlens structure (23), and at least one microlens structure (23) has a size different from that of the other microlens structures (23).

7. The light emitting device structure according to claim 6, characterized in that: The microlens structures (23) have the same radius of curvature, and at least one of the microlens structures (23) has a thickness different from that of the other microlens structures (23).

8. The light emitting device structure according to claim 6, characterized in that: The microlens structures (23) have the same thickness, and at least one of the microlens structures (23) has a different radius of curvature from the other microlens structures (23).

9. The light emitting device structure according to claim 1, characterized in that: The number of the microlens structures (23) corresponding to at least one of the light-emitting units is different from the number of the microlens structures (23) corresponding to other light-emitting units.

10. The light emitting device structure according to claim 1, characterized in that: The microlens structure (23) comprises at least one of a spherical convex lens, an aspherical convex lens, a spherical concave lens and an aspherical concave lens.

11. The light emitting device structure according to claim 1, characterized in that: The material of the buffer layer (20) includes at least one of AlN, GaN, AlGaN and AlInGaN.

12. The light emitting device structure according to claim 1, characterized in that: The light emitting device structure further comprises: A substrate structure (11) is located on a side of the buffer layer (20) away from the light-emitting structure (30), the substrate structure (11) having at least one opening (12) penetrating the substrate structure (11), and one of the light-emitting units corresponds to one of the openings (12).

13. The light emitting device structure according to claim 1, characterized in that: The light emitting device structure further comprises: An AlN film (24) is located on a surface of the microlens structure (23) that is away from the light-emitting structure (30).

14. The light emitting device structure according to claim 1, characterized in that: The light emitting device structure further comprises: A metal lens (25) having a dielectric hole is located on a surface of the microlens structure (23) on a side away from the light emitting structure (30).

15. The light emitting device structure according to claim 1, characterized in that: The microlens structure (23) further comprises: A first DBR layer (51), the first DBR layer (51) is located on a side of the microlens structure (23) close to the light emitting structure (30).

16. The light emitting device structure according to claim 1, characterized in that: The light emitting device structure further comprises: A second DBR layer (52), the second DBR layer (52) is located on a side of the light emitting structure (30) away from the microlens structure (23).

17. A method for preparing a light emitting device structure, characterized in that: The following steps are involved: S1. providing a substrate (10); S2, growing a buffer layer (20) made of a transparent material on the substrate (10); S3, growing a light-emitting structure (30) on the buffer layer (20), wherein the light-emitting structure (30) has at least one light-emitting unit; S4. The substrate (10) is removed by etching from a side away from the buffer layer (20), and at least one microlens structure (23) is formed by etching on a surface of the buffer layer (20) on a side away from the light-emitting structure (30), wherein the microlens structure (23) has at least two sublayers, and one of the light-emitting units corresponds to at least one of the microlens structures (23).

18. The method for preparing a light emitting device structure according to claim 17, characterized in that: The etching of the substrate (10) in step S4 is patterned etching, and the remaining substrate (10) becomes a substrate structure (11) serving as a retaining wall between two adjacent light-emitting units.

19. The method for preparing a light emitting device structure according to claim 17, characterized in that: The light-emitting units have the same size, one light-emitting unit corresponds to one microlens structure (23), and at least one microlens structure (23) has a size different from that of the other microlens structures (23).

20. The method for preparing a light emitting device structure according to claim 17, characterized in that: The number of the microlens structures (23) corresponding to at least one of the light-emitting units is different from the number of the microlens structures (23) corresponding to other light-emitting units.

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