Micro-display projection device and display device

Abstract

The invention relates to a micro-display projection device and a display device, and the micro-display projection device comprises a light combination structure which is provided with a first light-emitting surface and a plurality of first light-receiving surfaces for receiving light, and can combine image light beams passing through the plurality of first light-receiving surfaces and emit the image light beams from the first light-emitting surface; a plurality of micro display panels, each micro display panel having a light emitting surface from which light of one color is emitted; the light emitting surface of the micro display panel is opposite to the first light receiving surface; the plurality of super-surface lens structures are arranged in one-to-one correspondence with the plurality of micro-display panels; each metasurface lens structure is arranged corresponding to one side of the light-emitting surface of the corresponding micro display panel; and the light guide plate is clamped between the micro display panel and the light combination structure. According to the invention, the metasurface lens structure is arranged between the light combination structure and the micro-display panel, so that the purpose of reducing the three-dimensional size of the micro-display projection device can be achieved under the condition that the optical performance is not reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of micro light emitting diodes, and in particular to a micro display projection device and a display apparatus. Background Art

[0002] Micro-LED (Micro Light Emitting Diode) is an emerging display technology that miniaturizes traditional light-emitting diodes to micrometer-level size and integrates these tiny LED arrays onto a chip to form a high-density display panel. Compared with traditional organic light-emitting diodes (OLED) or liquid crystal display (LCD)-based microdisplays, Micro-LED has higher wall plug efficiency, higher brightness, lower efficiency drop, better thermal stability, longer life, faster response rate, higher resolution, higher color gamut, and higher contrast.

[0003] In the current Micro-LED-based projection technology, in order to achieve colored projection, the existing micro-display projection devices use three panels to emit red light, blue light and green light respectively, and then form a color image through a light-combining prism and an optical lens.

[0004] However, the three-dimensional size of existing Micro-LED-based micro-display projection devices needs to be further reduced. Summary of the invention

[0005] In order to solve at least part of the above problems in the prior art, the task of the present invention is to provide a micro display projection device, comprising:

[0006] A light combining structure, comprising a first light emitting surface and a plurality of first light receiving surfaces for receiving light, capable of combining image light beams passing through the plurality of first light receiving surfaces and emitting the image light beams from the first light emitting surface;

[0007] A plurality of micro display panels, each of which has a light emitting surface, emitting light of one color from the light emitting surface; each of the micro display panels comprises a pixel array; the light emitting surface of the micro display panel is arranged relative to the first light receiving surface; the plurality of micro display panels are arranged in one-to-one correspondence with the plurality of first light receiving surfaces of the light combining structure;

[0008] A plurality of metasurface lens structures are arranged in one-to-one correspondence with a plurality of microdisplay panels; each metasurface lens structure is arranged corresponding to one side of the light-emitting surface of the corresponding microdisplay panel; and is sandwiched between the microdisplay panel and the light-combining structure.

[0009] Furthermore, the metasurface lens structure is made of a metamaterial, and the metamaterial includes at least one of single crystal silicon, silicon oxide, aluminum oxide, and titanium oxide.

[0010] Furthermore, a plurality of the metasurface lens structures are integrally packaged.

[0011] Furthermore, the metasurface lens structure includes a plurality of atomic structures of the same shape.

[0012] Furthermore, the shape of the atomic structure includes at least one of a cylinder, a cube, a snowflake, a polyhedron, a truncated cone, and an irregular cylinder.

[0013] Furthermore, the cylindrical diameter is greater than or equal to 50 nanometers and less than or equal to 200 nanometers, and the height is greater than or equal to 300 nanometers and less than or equal to 2000 nanometers.

[0014] Furthermore, the width of the cube is greater than or equal to 50 nanometers and less than or equal to 200 nanometers, and the height is greater than or equal to 300 nanometers and less than or equal to 2000 nanometers.

[0015] Furthermore, the distance from the supersurface lens structure to the light-combining structure is greater than 0.2 mm, and the distance from the supersurface lens structure to the microdisplay panel is greater than or equal to 0.1 mm and less than or equal to 0.3 mm.

[0016] Furthermore, the metasurface lens structure includes a plurality of metasurface lens substructures stacked at a certain interval; each metasurface lens substructure includes a second light emitting surface and a second light receiving surface; the second light emitting surface of each metasurface lens substructure faces the first light receiving surface of the corresponding light combining structure, and the second light receiving surface of each metasurface lens substructure faces the light emitting surface of the corresponding micro display panel.

[0017] Furthermore, the thickness of the metasurface lens substructure is greater than or equal to 0.2 mm and less than or equal to 0.5 mm.

[0018] Furthermore, the metasurface lens structure and the micro display panel are fixedly connected; the fixed connection includes at least one of a gluing connection, a bonding connection, and a clamping connection.

[0019] Furthermore, the pixel array in the micro display panel is a micro light emitting diode array; and the light combining structure is a light combining prism.

[0020] Furthermore, the micro display panel comprises:

[0021] Driver backplane, including:

[0022] dielectric layer;

[0023] A driving circuit, located in the dielectric layer, and

[0024] a driving electrode, located in the dielectric layer, with at least an upper surface of the driving electrode exposed from the dielectric layer, the driving electrode being electrically connected to the driving circuit; and

[0025] The micro light emitting diode array is arranged on the driving back plate, and each micro light emitting diode in the micro light emitting diode array is electrically connected to the driving electrode of the driving back plate.

[0026] Furthermore, the micro light emitting diode includes a first semiconductor layer, a second semiconductor layer and a light emitting layer formed between the first semiconductor layer and the second semiconductor layer, the conductivity type of the first semiconductor layer is different from the conductivity type of the second semiconductor layer, and the light emitting layer includes a plurality of stacked layers.

[0027] The present invention also provides a display device, comprising the above-mentioned micro-display projection device.

[0028] The present invention has at least the following beneficial effects: a metasurface lens structure is provided in the micro-display projection device of the present invention. By providing the metasurface lens structure between the light-combining structure and the micro-display panel, the number of lenses of the optical lens can be reduced, the thickness of the optical lens can be reduced, and the optical lens can even be removed while ensuring that the optical performance is not reduced, thereby achieving the purpose of reducing the three-dimensional size of the micro-display projection device at a low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to further illustrate the above and other advantages and features of various embodiments of the present invention, a more specific description of various embodiments of the present invention will be presented with reference to the accompanying drawings. It will be understood that these drawings only depict typical embodiments of the present invention and are therefore not to be considered as limiting the scope thereof. In the accompanying drawings, for clarity, identical or corresponding parts will be represented by identical or similar reference numerals.

[0030] Figure 1 FIG. 1 is a schematic top view of a micro display projection device in the prior art.

[0031] Figure 2 FIG. 4 is a schematic top view of a micro display projection device according to a first embodiment of the present invention.

[0032] Figure 3 FIG. 4 is a schematic top view of a micro display projection device according to a second embodiment of the present invention.

[0033] Figure 4 FIG. 4 is a schematic top view of a micro display projection device according to a third embodiment of the present invention.

[0034] Figure 5 FIG. 4 is a schematic top view of a micro display projection device according to a fourth embodiment of the present invention.

[0035] Figure 6FIG. 4 is a schematic top view of a micro display projection device according to a fifth embodiment of the present invention.

[0036] Figure 7 FIG. 4 is a schematic top view of a micro display projection device according to a sixth embodiment of the present invention.

[0037] Figure 8 FIG. 4 is a schematic top view of a micro display projection device according to a seventh embodiment of the present invention.

[0038] Fig. 9 FIG. 8 is a schematic top view of a micro display projection device according to an eighth embodiment of the present invention.

[0039] Fig.10 FIG. 4 is a schematic top view of a micro display projection device according to a ninth embodiment of the present invention.

[0040] Fig.11 FIG. 1 is a schematic top view of a micro display projection device according to a tenth embodiment of the present invention.

[0041] Fig.12 FIG. 4 is a schematic top view of a micro display projection device according to an eleventh embodiment of the present invention.

[0042] Fig.13 FIG. 1 is a schematic top view of a micro display projection device according to a twelfth embodiment of the present invention.

[0043] Fig.14A A side view schematic diagram of the atomic structure of a metasurface lens according to an embodiment of the present invention is shown.

[0044] Fig. 14B A schematic top view of the atomic structure of a metasurface lens according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0045] It should be noted that various components in the various drawings may be shown exaggeratedly for illustrative purposes and are not necessarily correct to scale.

[0046] In the present invention, each embodiment is only intended to illustrate the aspects of the present invention and should not be construed as limiting.

[0047] In the present invention, unless otherwise specified, the quantifiers "a", "an" and "an" do not exclude the presence of a plurality of elements.

[0048] It should also be pointed out that in the embodiments of the present invention, for the sake of clarity and simplicity, only a portion of the parts or components may be shown, but a person of ordinary skill in the art will understand that under the teachings of the present invention, required parts or components may be added as needed in specific scenarios.

[0049] It should also be pointed out that within the scope of the present invention, the terms "same", "equal", "equal to" and the like do not mean that the two values ​​are absolutely equal, but allow a certain reasonable error, that is, the terms also cover "substantially the same", "substantially equal", and "substantially equal to".

[0050] It should also be pointed out that in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than explicitly or implicitly indicating that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as explicitly or implicitly indicating relative importance.

[0051] In addition, the embodiments of the present invention describe the process steps in a specific order, but this is only for the convenience of distinguishing the steps, and does not limit the sequence of the steps. In different embodiments of the present invention, the sequence of the steps can be adjusted according to the adjustment of the process.

[0052] In the present application, the term "configuration" refers to the setting of the shape, structure, material and / or function of the target object to achieve the desired technical effect, wherein "configuration" includes a variety of alternative technical means for achieving the technical effect, which become obvious under the teaching of the present application.

[0053] In the present invention, the term "horizontal profile" has the following meanings: for regular shapes, it refers to the horizontal dimension, and for irregular shapes, it refers to the maximum horizontal dimension. For example, for a hemispherical microlens, its horizontal profile refers to its bottom diameter, and for a cylindrical micro-LED, its horizontal profile refers to the diameter of its cylindrical cross section. The maximum horizontal profile refers to the maximum value of the dimensions.

[0054] Figure 1 FIG. 2 shows a schematic top view of a micro display projection device in the prior art. Figure 1 As shown, the existing micro display projection device includes a plurality of micro display panels 11, a light combining prism 12 and an optical lens 13. The plurality of micro display panels emit red light, blue light and green light respectively. A lens group is provided in the optical lens 13, and the lens group includes a plurality of lenses. The light emitted by the light emitting element passes through the light combining prism 12 and the lens group in the optical lens 13, and can form a color image.

[0055] The optical lens in the current micro display projection device has a large number of lenses, usually 4 or 5 lenses, which makes the thickness of the optical lens 13 thicker, so that the three-dimensional size of the micro display projection device needs to be further reduced so that it can be more lightweight and easy to use in a near-eye display device.

[0056] The present invention provides a micro-display projection device, in which a metasurface lens structure is arranged between a micro-display panel and a light-combining structure, which can reduce the number of lenses of an optical lens, reduce the thickness of the optical lens, and even remove the optical lens, thereby achieving the purpose of reducing the three-dimensional size of the micro-display projection device while ensuring the optical performance.

[0057] Metasurface lenses converge or diverge light, which is the same as the function of optical lenses. Metasurface lenses are a type of flat lens that can be packaged in a semiconductor package together with a semiconductor display panel (micro display panel). This can reduce the number of traditional refractive lenses that originally required four or five to only three or two to achieve the same optical performance. Ideally, a fully semiconductor-packaged micro-projection optical module (light engine) without traditional refractive lenses can be realized. Simplifying the optical part after light combination can greatly reduce the development cost and production efficiency of the optical lens group, giving Micro-LED a stronger competitive advantage in mass market applications. This feature cannot be applied to modules with digital light processing technology (DLP) or liquid crystal on silicon (LCOS) optical architectures.

[0058] Metasurface lenses have extremely high requirements for spectral bandwidth in imaging applications, so it is difficult to make breakthroughs in the field of imaging applications. However, for display panels based on monochrome micro-LEDs, due to their narrow spectral bandwidth, after passing through metasurface lenses, the interference between multiple bands can be greatly reduced, and better imaging quality can be achieved. The metasurface lens, combined with the light-combining structure, can fuse the high-quality projected images of the three-primary color display, so it has very obvious advantages in cost and size.

[0059] Figure 2 FIG. 2 shows a schematic top view of a micro display projection device according to a first embodiment of the present invention. Figure 2 As shown, a micro-display projection device includes multiple micro-display panels, a light-combining structure 102 and multiple metasurface lens structures.

[0060] In one embodiment, the light combining structure 102 has a first light emitting surface and a plurality of first light receiving surfaces for receiving light, and can combine image light beams passing through the plurality of first light receiving surfaces and emit from the first light emitting surface. In one embodiment, the light combining structure 102 includes a first light emitting surface and three first light receiving surfaces.

[0061] In one embodiment, the light combining structure 102 is a light combining prism. The light combining prism includes four right-angle prisms, the right-angle surfaces of the four right-angle prisms are aligned and bonded to each other, and the oblique surfaces of the four right-angle prisms constitute the four surfaces of the light combining prism, and the four surfaces include a first light receiving surface and a first light emitting surface. Further, the four surfaces of the light combining prism include a first light emitting surface and three first light collecting surfaces. In other embodiments, the four surfaces of the light combining prism may include a first light emitting surface and two first light receiving surfaces.

[0062] In one embodiment, each of the plurality of micro display panels has a light emitting surface, and emits light of one color from the light emitting surface. In one embodiment, the light emitting surface of the micro display panel is arranged relative to the first light receiving surface of the light combining structure 102. In one embodiment, each micro display panel includes a pixel array, and the pixel array is a micro light emitting diode array.

[0063] In one embodiment, the plurality of micro display panels are arranged in a one-to-one correspondence with the plurality of first light collecting surfaces of the light combining structure.

[0064] In one embodiment, the plurality of micro display panels include a first micro display panel 1011 , a second micro display panel 1012 , and a third micro display panel 1013 emitting lights of different colors.

[0065] In one embodiment, the first micro display panel 1011 is configured to emit a first light, and the first light is blue light. In other embodiments, the first light may also be red light or green light.

[0066] In one embodiment, the second micro display panel 1012 is configured to emit a second light, and the second light is red light. In other embodiments, the second light may also be blue light or green light.

[0067] In one embodiment, the third micro display panel 1013 is configured to emit a third light, and the third light is green light. In other embodiments, the third light may also be red light or blue light.

[0068] In one embodiment, a plurality of metasurface lens structures are arranged in one-to-one correspondence with a plurality of microdisplay panels; each metasurface lens structure is arranged corresponding to one side of the light-emitting surface of the corresponding microdisplay panel; and is sandwiched between the microdisplay panel and the light-combining structure 102.

[0069] In one embodiment, a plurality of metasurface lens structures are integrally packaged.

[0070] In one embodiment, the number of the metasurface lens structures is three, and each metasurface lens structure includes a metasurface lens substructure 103. The three metasurface lens structures are respectively located between the light-combining structure 102 and the first microdisplay panel 1011, the second microdisplay panel 1012, and the third microdisplay panel 1013. The metasurface lens substructure 103 includes a second light-emitting surface and a second light-collecting surface, the second light-emitting surface faces the first light-collecting surface of the corresponding light-combining structure, and the second light-collecting surface of the metasurface lens substructure faces the light-emitting surface of the corresponding microdisplay panel.

[0071] In other embodiments, the metasurface lens structure includes a plurality of metasurface lens substructures stacked at a certain interval; each metasurface lens substructure includes a second light emitting surface and a second light receiving surface; the second light emitting surface of each metasurface lens substructure faces the first light receiving surface of the corresponding light combining structure, and the second light receiving surface of each metasurface lens substructure faces the light emitting surface of the corresponding micro display panel.

[0072] In one embodiment, multiple super-surface lens structures of each super-surface lens structure are integrally packaged.

[0073] It should be pointed out here that this is merely exemplary, and under the teachings of the present invention, other numbers of metasurface lens structures and their arrangements are also conceivable.

[0074] In one embodiment, the metasurface lens structure is made of a metamaterial, wherein the metamaterial includes at least one of single crystal silicon or an inorganic oxide, wherein the inorganic oxide may include silicon oxide, aluminum oxide, titanium oxide, or the like.

[0075] In one embodiment, a fixed connection is adopted between the metasurface lens structure and the micro display panel; the fixed connection includes at least one of a gluing connection, a bonding connection, and a clamping connection.

[0076] In one embodiment, an adhesive may be used to bond the metasurface lens structure to the microdisplay panel. The adhesive may be a transparent adhesive or a black adhesive. When a black adhesive is used, the adhesive is applied around the edge of the metasurface lens structure.

[0077] In one embodiment, the metasurface lens structure includes a plurality of atomic structures of the same shape. The metasurface lens substructure has a plurality of atomic structures of the same shape. In one embodiment, the shape of the atomic structure may include at least one of a cylinder, a cube, a snowflake, a truncated cone, a polyhedron, and an irregular cylinder. The cross-section of the atomic structure in the shape of a polyhedron is a polygon. The cross-section of the atomic structure in the shape of an irregular cylinder is an irregular closed curve. In one embodiment, the diameter of the cylindrical atomic structure is greater than or equal to 50 nanometers and less than or equal to 200 nanometers, and the height is greater than or equal to 300 nanometers and less than or equal to 2000 nanometers. In one embodiment, the width of the cube is greater than or equal to 50 nanometers and less than or equal to 200 nanometers, and the height is greater than or equal to 300 nanometers and less than or equal to 2000 nanometers.

[0078] In one embodiment, the multiple atomic structures of the metasurface lens structure are arranged in an array. The sizes of the multiple atomic structures of the metasurface lens structure can be the same or different.

[0079] In one embodiment, Fig.14A and 14B As shown, the metasurface lens structure includes a plurality of truncated cone-shaped atomic structures 1031 of different sizes. The bottom size of the truncated cone-shaped atomic structure 1031 is larger than the top size.

[0080] In one embodiment, the thickness of the metasurface lens substructure is greater than or equal to 0.2 mm and less than or equal to 0.5 mm.

[0081] In one embodiment, the distance from the metasurface lens structure to the light combining structure 102 is greater than 0.2 mm, and the distance from the metasurface lens structure to the micro display panel is greater than or equal to 0.1 mm and less than or equal to 0.3 mm. In one embodiment, the distances between multiple metasurface lens structures and the relative micro display panels can be different or the same.

[0082] When the total number of metasurface lens substructures is less than 6, the micro-display projection device also needs to be provided with an optical lens 104. In one embodiment, the optical lens 104 is arranged opposite to the first light-emitting surface of the light-combining structure 102, and the light emitted by the light-combining structure 102 passes through the optical lens and is emitted. In one embodiment, the optical lens 104 includes a plurality of lenses. Furthermore, the optical lens 104 includes two or three lenses. Compared with a micro-display projection device without a metasurface lens structure, the thickness of the optical lens 104 of the micro-display projection device provided with a metasurface lens structure is reduced.

[0083] In one embodiment, the first micro display panel 1011 and the second micro display panel 1012 are respectively located on both sides of the light combining structure 102 in the first direction X, and the third micro display panel 1013 and the optical lens 104 are respectively located on both sides of the light combining structure 102 in the second direction Y, and the first direction X and the second direction Y are perpendicular to each other. The light combining structure 102 can adjust the light emitted by two of the three light emitting elements so that the light emitted by the two light emitting elements enters the optical lens 102 together with the light emitted by the other light emitting element.

[0084] Figure 3 FIG. 4 is a schematic top view of a micro display projection device according to a second embodiment of the present invention.

[0085] The same points as the first embodiment are not repeated here. The difference from the first embodiment is that the three metasurface lens structures are respectively located between the light-combining structure 102 and the first microdisplay panel 1011, the second microdisplay panel 1012 and the third microdisplay panel 1013, wherein the metasurface lens structure between the light-combining structure 102 and the first microdisplay panel 1011 and the second microdisplay panel 1012 includes one metasurface lens substructure 103, and the metasurface lens structure between the light-combining structure 102 and the third microdisplay panel 1013 includes two metasurface lens substructures 103. The two metasurface lens substructures 103 are stacked at a certain distance.

[0086] The second light emitting surface of each metasurface lens substructure 103 faces the first light receiving surface of the corresponding light combining structure 102 , and the second light receiving surface of each metasurface lens substructure faces the light emitting surface of the corresponding micro display panel.

[0087] In another embodiment, the metasurface lens structure between the light-combining structure 102 and the third microdisplay panel 1013 and the second microdisplay panel 1012 includes one metasurface lens substructure 103 , and the metasurface lens structure between the light-combining structure 102 and the first microdisplay panel 1011 includes two metasurface lens substructures 103 .

[0088] In another embodiment, the metasurface lens structure between the light-combining structure 102 and the first microdisplay panel 1011 and the third microdisplay panel 1013 includes one metasurface lens substructure 103 , and the metasurface lens structure between the light-combining structure 102 and the second microdisplay panel 1012 includes two metasurface lens substructures 103 .

[0089] The thickness of the optical lens of the second embodiment is smaller than the thickness of the optical lens of the first embodiment.

[0090] Figure 4 FIG. 4 is a schematic top view of a micro display projection device according to a third embodiment of the present invention.

[0091] The same points as the first embodiment are not repeated here. The difference from the first embodiment is that the three metasurface lens structures are respectively located between the light-combining structure 102 and the first microdisplay panel 1011, the second microdisplay panel 1012 and the third microdisplay panel 1013, wherein the metasurface lens structure between the light-combining structure 102 and the first microdisplay panel 1011 and the second microdisplay panel 1012 includes two metasurface lens substructures 103, and the metasurface lens structure between the light-combining structure 102 and the third microdisplay panel 1013 includes one metasurface lens substructure 103. The two metasurface lens substructures 103 are stacked at a certain distance.

[0092] The second light emitting surface of each metasurface lens substructure 103 faces the first light receiving surface of the corresponding light combining structure 102 , and the second light receiving surface of each metasurface lens substructure faces the light emitting surface of the corresponding micro display panel.

[0093] In another embodiment, the metasurface lens structure between the light-combining structure 102 and the third microdisplay panel 1013 and the second microdisplay panel 1012 includes two metasurface lens substructures 103 , and the metasurface lens structure between the light-combining structure 102 and the first microdisplay panel 1011 includes one metasurface lens substructure 103 .

[0094] In another embodiment, the metasurface lens structure between the light-combining structure 102 and the first microdisplay panel 1011 and the third microdisplay panel 1013 includes two metasurface lens substructures 103 , and the metasurface lens structure between the light-combining structure 102 and the second microdisplay panel 1012 includes one metasurface lens substructure 103 .

[0095] The thickness of the optical lens of the third embodiment is smaller than that of the optical lens of the first embodiment.

[0096] Figure 5 FIG. 4 is a schematic top view of a micro display projection device according to a fourth embodiment of the present invention.

[0097] The same points as the first embodiment are not repeated here. The difference from the first embodiment is that the three metasurface lens structures are respectively located between the light-combining structure 102 and the first microdisplay panel 1011, the second microdisplay panel 1012 and the third microdisplay panel 1013, wherein the metasurface lens structure between the light-combining structure 102 and the first microdisplay panel 1011 and the second microdisplay panel 1012 includes a metasurface lens substructure 103, and the metasurface lens structure between the light-combining structure 102 and the third microdisplay panel 1013 includes three metasurface lens substructures 103. The three metasurface lens substructures 103 are stacked at a certain interval.

[0098] The second light emitting surface of each metasurface lens substructure 103 faces the first light receiving surface of the corresponding light combining structure 102 , and the second light receiving surface of each metasurface lens substructure faces the light emitting surface of the corresponding micro display panel.

[0099] In another embodiment, the metasurface lens structure between the light-combining structure 102 and the third microdisplay panel 1013 and the second microdisplay panel 1012 includes one metasurface lens substructure 103 , and the metasurface lens structure between the light-combining structure 102 and the first microdisplay panel 1011 includes three metasurface lens substructures 103 .

[0100] In another embodiment, the metasurface lens structure between the light-combining structure 102 and the first microdisplay panel 1011 and the third microdisplay panel 1013 includes one metasurface lens substructure 103 , and the metasurface lens structure between the light-combining structure 102 and the second microdisplay panel 1012 includes three metasurface lens substructures 103 .

[0101] The thickness of the optical lens of the fourth embodiment is smaller than the thickness of the optical lens of the first embodiment.

[0102] Figure 6 FIG. 4 is a schematic top view of a micro display projection device according to a fifth embodiment of the present invention.

[0103] The same points as the first embodiment are not described here. The difference from the first embodiment is that there is no optical lens, and the three metasurface lens structures are respectively located between the light combining structure 102 and the first micro display panel 1011, the second micro display panel 1012 and the third micro display panel 1013, and each metasurface lens structure includes two metasurface lens substructures 103. The two metasurface lens substructures are stacked at a certain distance.

[0104] The second light emitting surface of each metasurface lens substructure 103 faces the first light receiving surface of the corresponding light combining structure 102 , and the second light receiving surface of each metasurface lens substructure faces the light emitting surface of the corresponding micro display panel.

[0105] When the total number of metasurface lenses is greater than or equal to 6, no optical lens is required.

[0106] It should be pointed out here that this is merely exemplary, and other arrangements of the six metasurface lenses are also conceivable under the teachings of the present invention.

[0107] Figure 7 FIG. 4 is a schematic top view of a micro display projection device according to a sixth embodiment of the present invention.

[0108] The same as the first embodiment is not repeated here. The difference from the first embodiment is that there is no optical lens, and the three super-surface lens structures are respectively located between the light-combining structure 102 and the first micro-display panel 1011, the second micro-display panel 1012 and the third micro-display panel 1013, wherein the super-surface lens structure between the light-combining structure 102 and the first micro-display panel 1011 includes two super-surface lens sub-structures 103, the super-surface lens structure between the light-combining structure 102 and the second micro-display panel 1012 includes three super-surface lens sub-structures 103, and the super-surface lens structure between the light-combining structure 102 and the third micro-display panel 1013 includes one super-surface lens sub-structure 103. The two super-surface lens sub-structures between the light-combining structure 102 and the first micro-display panel 1011 are stacked at a certain distance. The three super-surface lens sub-structures between the light-combining structure 102 and the second micro-display panel 1012 are stacked at a certain distance.

[0109] The second light emitting surface of each metasurface lens substructure 103 faces the first light receiving surface of the corresponding light combining structure 102 , and the second light receiving surface of each metasurface lens substructure faces the light emitting surface of the corresponding micro display panel.

[0110] In another embodiment, the metasurface lens structure between the light-combining structure 102 and the first microdisplay panel 1011 includes one metasurface lens substructure 103, the metasurface lens structure between the light-combining structure 102 and the second microdisplay panel 1012 includes two metasurface lens substructures 103, and the metasurface lens structure between the light-combining structure 102 and the third microdisplay panel 1013 includes three metasurface lens substructures 103.

[0111] In another embodiment, the metasurface lens structure between the light-combining structure 102 and the first microdisplay panel 1011 includes three metasurface lens substructures 103, the metasurface lens structure between the light-combining structure 102 and the second microdisplay panel 1012 includes two metasurface lens substructures 103, and the metasurface lens structure between the light-combining structure 102 and the third microdisplay panel 1013 includes one metasurface lens substructure 103.

[0112] In another embodiment, the metasurface lens structure between the light-combining structure 102 and the first microdisplay panel 1011 includes a metasurface lens substructure 103, the metasurface lens structure between the light-combining structure 102 and the second microdisplay panel 1012 includes a metasurface lens substructure 103, and the metasurface lens structure between the light-combining structure 102 and the third microdisplay panel 1013 includes four metasurface lens substructures 103.

[0113] Figure 8 FIG. 4 is a schematic top view of a micro display projection device according to a seventh embodiment of the present invention. Figure 8 As shown, a micro display projection device includes a plurality of micro display panels, a light combining structure 102 and an optical lens 104 .

[0114] The same as the first embodiment mentioned above will not be repeated here. The difference from the first embodiment mentioned above is that the multiple micro display panels include two micro display panels that emit light of different colors. In one embodiment, the multiple micro display panels include a first micro display panel 1011 and a second micro display panel 1012. In one embodiment, the first micro display panel 1011 is configured to emit a first light, and the second micro display panel 1012 is configured to emit a second light, wherein the first light is a monochromatic light, and the second light is a two-color mixed light, and the two-color mixed light includes a second light and a third light of different colors, and the first light has a different color from the second light and the third light. In one embodiment, the first light is red light, and the second light and the third light are blue light and green light, respectively. In one embodiment, the first light is blue light, and the second light and the third light are red light and green light, respectively. In one embodiment, the first light is green light, and the second light and the third light are red light and blue light, respectively.

[0115] In one embodiment, the first micro display panel 1011 is located on one side of the light combining structure 102 in the first direction X, and the second micro display panel 1012 and the optical lens 104 are respectively located on both sides of the light combining structure 102 in the second direction Y, and the first direction and the second direction are perpendicular to each other.

[0116] In other embodiments, the first micro display panel 1011 and the optical lens 104 are respectively located on both sides of the light combining structure 102 in the second direction Y, and the second micro display panel 1012 is located on one side of the light combining structure 102 in the first direction X. Alternatively, the first micro display panel 1011 and the second micro display panel 1012 are respectively located on both sides of the light combining structure 102 in the first direction X.

[0117] In one embodiment, the light combining structure 102 includes a first light emitting surface and two first light receiving surfaces, and the two first light receiving surfaces are respectively opposite to the first micro display panel 1011 and the optical lens 104. In one embodiment, the light combining structure 102 includes a light combining prism. The four surfaces of the light combining prism include a first light emitting surface and two first light receiving surfaces.

[0118] In one embodiment, the metasurface lens structure includes one or more metasurface lens substructures 103. Further, the number of the metasurface lens structures is two, and each metasurface lens structure includes a metasurface lens substructure 103. The two metasurface lens structures are respectively located between the light-combining structure 102 and the first micro-display panel 1011 and the second micro-display panel 1012. It should be noted here that this is merely exemplary, and under the teachings of the present invention, other numbers of metasurface lens structures and their arrangements are also conceivable. Compared to a micro-display projection device without a metasurface lens structure, the thickness of the optical lens 104 of the micro-display projection device with a metasurface lens structure is reduced.

[0119] Fig. 9 FIG. 8 is a schematic top view of a micro display projection device according to an eighth embodiment of the present invention.

[0120] The same points as the seventh embodiment are not repeated here. The difference from the seventh embodiment is that the two metasurface lens structures are respectively located between the light-combining structure 102 and the first microdisplay panel 1011 and the second microdisplay panel 1012, wherein the metasurface lens structure located between the light-combining structure 102 and the first microdisplay panel 1011 includes a metasurface lens substructure 103, and the metasurface lens structure located between the light-combining structure 102 and the second microdisplay panel 1012 includes two metasurface lens substructures 103. The two metasurface lens substructures are stacked at a certain distance.

[0121] The second light emitting surface of each metasurface lens substructure 103 faces the first light receiving surface of the corresponding light combining structure 102 , and the second light receiving surface of each metasurface lens substructure faces the light emitting surface of the corresponding micro display panel.

[0122] In another embodiment, the metasurface lens structure located between the light-combining structure 102 and the first microdisplay panel 1011 includes two metasurface lens substructures 103 , and the metasurface lens structure located between the light-combining structure 102 and the second microdisplay panel 1012 includes one metasurface lens substructure 103 .

[0123] The thickness of the optical lens of the eighth embodiment is smaller than the thickness of the optical lens of the seventh embodiment.

[0124] Fig.10 FIG. 4 is a schematic top view of a micro display projection device according to a ninth embodiment of the present invention.

[0125] The same points as the seventh embodiment are not described here. The difference from the seventh embodiment is that the two metasurface lens structures are respectively located between the light combining structure 102 and the first micro display panel 1011 and the second micro display panel 1012, wherein each metasurface lens structure includes two metasurface lens substructures 103. The two metasurface lens substructures are stacked at a certain distance.

[0126] The second light emitting surface of each metasurface lens substructure 103 faces the first light receiving surface of the corresponding light combining structure 102 , and the second light receiving surface of each metasurface lens substructure faces the light emitting surface of the corresponding micro display panel.

[0127] The thickness of the optical lens of the ninth embodiment is smaller than the thickness of the optical lens of the seventh embodiment.

[0128] Fig.11 FIG. 1 is a schematic top view of a micro display projection device according to a tenth embodiment of the present invention.

[0129] The similarities with the aforementioned seventh embodiment are not repeated here. The difference from the aforementioned seventh embodiment is that the two metasurface lens structures are respectively located between the light-combining structure 102 and the first microdisplay panel 1011 and the second microdisplay panel 1012, wherein the metasurface lens structure located between the light-combining structure 102 and the first microdisplay panel 1011 includes two metasurface lens substructures 103, and the metasurface lens structure located between the light-combining structure 102 and the second microdisplay panel 1012 includes three metasurface lens substructures 103. The multiple metasurface lens substructures 103 in the metasurface lens structure are stacked at a certain interval. The second light-emitting surface of each metasurface lens substructure 103 faces the first light-collecting surface of the corresponding light-combining structure 102, and the second light-collecting surface of each metasurface lens substructure faces the light-emitting surface of the corresponding microdisplay panel.

[0130] In another embodiment, the metasurface lens structure located between the light-combining structure 102 and the first microdisplay panel 1011 includes three metasurface lens substructures 103 , and the metasurface lens structure located between the light-combining structure 102 and the second microdisplay panel 1012 includes two metasurface lens substructures 103 .

[0131] The thickness of the optical lens of the tenth embodiment is smaller than the thickness of the optical lens of the seventh embodiment.

[0132] Fig.12 FIG. 4 is a schematic top view of a micro display projection device according to an eleventh embodiment of the present invention.

[0133] The similarities with the aforementioned seventh embodiment are not repeated here. The difference from the aforementioned seventh embodiment is that there is no optical lens, and the two metasurface lens structures are respectively located between the light-combining structure 102 and the first microdisplay panel 1011 and the second microdisplay panel 1012, wherein each metasurface lens structure includes three metasurface lens substructures 103. The multiple metasurface lens substructures 103 in the metasurface lens structure are stacked at a certain interval. The second light-emitting surface of each metasurface lens substructure 103 faces the first light-collecting surface of the corresponding light-combining structure 102, and the second light-collecting surface of each metasurface lens substructure faces the light-emitting surface of the corresponding microdisplay panel.

[0134] Fig.13 FIG. 1 is a schematic top view of a micro display projection device according to a twelfth embodiment of the present invention.

[0135] The present invention will not repeat the same points as the aforementioned seventh embodiment. The difference from the aforementioned seventh embodiment is that there is no optical lens, and the two super-surface lens structures are respectively located between the light-combining structure 102 and the first micro-display panel 1011 and the second micro-display panel 1012, wherein the super-surface lens structure between the light-combining structure 102 and the first micro-display panel 1011 includes two super-surface lens sub-structures 103, and the super-surface lens structure between the light-combining structure 102 and the second micro-display panel 1012 includes four super-surface lens sub-structures 103. The multiple super-surface lens sub-structures 103 in the super-surface lens structure are stacked at a certain interval. The second light-emitting surface of each super-surface lens sub-structure 103 faces the first light-collecting surface of the corresponding light-combining structure 102, and the second light-collecting surface of each super-surface lens sub-structure faces the light-emitting surface of the corresponding micro-display panel.

[0136] In another embodiment, the metasurface lens structure between the light-combining structure 102 and the first microdisplay panel 1011 includes four metasurface lens substructures 103 , and the metasurface lens structure between the light-combining structure 102 and the second microdisplay panel 1012 includes two metasurface lens substructures 103 .

[0137] Accordingly, an embodiment of the present invention further provides a display device, comprising: the micro display projection device as described above. The display device includes but is not limited to a near-eye display device, a projector with a screen, and the like.

[0138] In one embodiment, the near-eye display device includes a micro-display projection device, an optical waveguide, a driving module, a power supply module, and a circuit module.

[0139] In one embodiment, the near-eye display device may be AR glasses, VR equipment, mediated reality equipment (Mediated Reality, abbreviated as MR), etc.

[0140] The metasurface lens is introduced in detail below.

[0141] Metasurface lens (hereafter referred to as superlens) is a two-dimensional planar lens structure made of planar two-dimensional (2D) metamaterials with subwavelength thickness. These metamaterials, namely metasurfaces, are a series of artificially designed antennas that can precisely manipulate the optical response of incident light, including its amplitude, phase and polarization. This technology enables superlenses to achieve complex optical functions in extremely small sizes, providing unprecedented flexibility in the design and application of optical components.

[0142] There are two main types of metasurface structures for superlenses: dielectric and plasma. Dielectric metasurfaces are made of dielectric materials that are already used in many standard optical components and can produce subwavelength scattering. They can operate over a wide bandwidth and introduce phase delays to achieve aberration-free, diffraction-limited, polarization-independent focusing. Plasmonic metasurfaces use amplitude shaping of electromagnetic radiation, and their plasmon modes are well-defined and can be used over a wide wavelength range. By adding layers to filter out higher-order plasmon modes, the efficiency of the lens can be improved.

[0143] When designing a metalens, the geometry of the surface scattering points must be considered, and each unit cell affects the characteristics of the electromagnetic radiation. The precise design of the metalens enables it to avoid the image deformation and distortion problems common in traditional lenses. Studies have shown that sub-diffraction focusing achieved using a metalens can significantly improve the spatial resolution of the instrument, especially in the field of short-wavelength lithography. The metalens achieves control of properties such as polarization, phase, and amplitude of light by adjusting parameters such as the shape, rotation direction, and height of the structure.

[0144] The micro display panel is described in detail below.

[0145] In some embodiments, the micro display panel includes a driving backplane; a micro light emitting diode array, which is disposed on the driving backplane and is configured to emit light. The micro light emitting diode array includes a plurality of micro light emitting diodes arranged in an array. In some embodiments, the micro light emitting diodes can be arranged on the driving backplane in a regular or irregular manner as pixels of the micro display panel.

[0146] In some embodiments, the length and width of the light emitting area of ​​the micro display panel range from a few millimeters to a hundred micrometers, and the light emitting area includes a plurality of micro light emitting diode structures arranged in an array.

[0147] Micro LEDs are formed in an array in a micro display panel with a resolution of, for example, 720*480, 640*480, 1920*1080, 1280*720, 2K or 4K. The diameter of the micro LED structure is at the nanometer level, for example, 20nm to 100nm.

[0148] In some embodiments, the pitch of the micro LED array, ie, the minimum center-to-center distance between the micro LEDs, can be between about 2 microns and about 50 microns. In some embodiments, the number of pixels on the micro display panel can be between thousands and millions.

[0149] In some embodiments, the drive backplane can be electrically connected to each micro-LED in the micro-LED array via a separate metal interconnect. In some embodiments, each micro-LED can be electrically controlled individually by the drive backplane. In some embodiments, the drive backplane can be electrically connected to the electrodes of the micro-display panel via a metal interconnect. In some embodiments, the drive backplane is an IC backplane.

[0150] In some embodiments, the driving backplane includes a dielectric layer, a driving circuit, and a plurality of driving electrodes. The driving circuit is located in the dielectric layer to control the lighting and extinguishing of the micro-LEDs; the driving electrodes are located in the dielectric layer, and at least the upper surface is exposed from the dielectric layer, and the driving electrodes are electrically connected to the driving circuit. Each micro-LED corresponds to a driving electrode, and the micro-LED is located on the driving electrode and is electrically connected to the driving electrode.

[0151] In some embodiments, the material of the driving electrode is an alloy of one or more of the following metals: Ni, Al, Ti, Cu, Pt and Au. In some embodiments, the dielectric layer is a Si dielectric layer. In other embodiments, the dielectric layer is a transparent dielectric layer. In some embodiments, the dielectric layer is about 700 microns thick. The driving circuit forms an individual pixel driver to control the operation of each single pixel LED device. The driving circuit includes, for example, a complementary metal oxide semiconductor (CMOS) device or a TFT device. In some embodiments, a dielectric layer can be formed in the gap between the micro light emitting diodes. In some embodiments, the dielectric layer can also be formed in the gap between the interconnections.

[0152] The driving mode of the micro LED is, for example, a passive matrix (PM) driving mode, in which the cathodes of all the micro LEDs in each array are connected to the cathode line NL, and the micro LEDs with the same number in each array are connected to the corresponding anode line PL. Thus, the on / off and the light brightness of each LED can be individually controlled by controlling the number of the corresponding cathode line and anode line.

[0153] In some embodiments, the micro-LED can be bonded to the surface of the driving backplane through a bonding layer. The driving electrode is electrically connected to the bonding layer, and the bonding layer includes a first metal layer and a second metal layer. In some embodiments, the material of the first metal layer is an alloy of one or more of the following metals: Cr, Al, Ti, Ni, Pt, Au, and Sn; and / or the material of the second metal layer is an alloy of one or more of the following metals: Cr, Al, Ti, Ni, Pt, Au, and Sn.

[0154] In some embodiments, the micro-light emitting diode includes: an epitaxial layer, an ohmic contact layer, a top conductive layer, and a passivation insulating layer. The ohmic contact layer is located on the bonding layer and is electrically connected to the bonding layer. The epitaxial layer is arranged on the ohmic contact layer. The passivation insulating layer at least partially covers the side of the epitaxial layer, and the passivation insulating layer is located between the epitaxial layer and the top conductive layer. The top conductive layer is located on the side and top surface of the epitaxial layer.

[0155] In some embodiments, the material of the passivation isolation layer is, for example, a solid inorganic material or a plastic material. In some embodiments, the solid inorganic material includes SiO2, Al2O3, Si3N4, SiCN, HfO2, Ta2O5, TiO2, ZrO2, La2O3, MgO, phosphosilicate glass (PSG), borophosphosilicate glass (BPSG) or any combination thereof. In some embodiments, the plastic material includes a polymer such as SU-8, PermiNex, benzocyclobutene (BCB), or a transparent plastic (resin) including spin-on glass (SOG), or a microresist BCL-1200 in combination with an adhesive, or any combination thereof. The passivation isolation layer is transparent to the light emitted by the epitaxial layer.

[0156] In some embodiments, the first metal layer of the bonding layer is in direct contact with the ohmic contact layer at the bottom of the epitaxial layer, and the second metal layer is located at the bottom of the bonding layer, away from the epitaxial layer, wherein the profile of the first metal layer is smaller than that of the second metal layer.

[0157] In some embodiments, the epitaxial layer has a bottom lateral dimension greater than a top lateral dimension. In some embodiments, the epitaxial layer is stepped or trapezoidal.

[0158] In some embodiments, the epitaxial layer is trapezoidal, not limited to a regular trapezoid or an inverted trapezoid. In some embodiments, the sidewall of the epitaxial layer has an inclination angle ranging from 60° to 85°. In one embodiment, the lateral dimension of the bonding layer is greater than the bottom lateral dimension of the epitaxial layer.

[0159] In some embodiments, the epitaxial layer includes a first semiconductor layer, a second semiconductor layer and a light emitting layer therebetween. The first semiconductor layer is located above the light emitting layer and away from the driving backplane, and the second semiconductor layer is located below the light emitting layer and close to the driving backplane.

[0160] In some embodiments, the light emitting layer is formed by a plurality of stacked quantum well layers, in particular, quantum well layers stacked in a superlattice. Preferably, the quantum well layers stacked in a superlattice include a plurality of pairs of quantum well layers stacked with quantum barrier layers.

[0161] In one embodiment, the light emitting layer includes a multi-quantum well layer and an electron blocking layer, and the multi-quantum well layer is an InGaN / GaN multi-quantum well layer or an InGaN / AlGaN multi-quantum well layer or an InGaAs / AlGaAs multi-quantum well layer. In another embodiment, the first semiconductor layer may also be a P-type GaN layer or a P-type AlGaN layer, and the second semiconductor layer may be an N-type GaN layer or an N-type AlGaN layer.

[0162] In some embodiments, the first semiconductor layer is a semiconductor material having a first conductivity type and includes a plurality of semiconductor layers. The main matrix material of the first semiconductor layer may be, but is not limited to, at least two or more elements of Ga, N, As, P, In and Al. In addition, the first type of epitaxial layer may include, from top to bottom, but is not limited to, a confinement layer and a waveguide layer; in addition, in some embodiments, an ohmic contact layer may be formed on the confinement layer.

[0163] In some embodiments, the second type epitaxial layer is a semiconductor material having a second conductivity type and includes a plurality of semiconductor layers. The main matrix material of the second type epitaxial layer may be, but is not limited to, Ga, N, As, P, In or Al. In addition, the second type epitaxial layer may include, from top to bottom, but is not limited to, a waveguide layer, a confinement layer, a transition layer and a window layer; in addition, an ohmic contact layer may be formed below the window layer. The second conductivity type is different from the first conductivity type.

[0164] In some embodiments, one of the first semiconductor layer and the second semiconductor layer is an N-type semiconductor layer, and the other is a P-type semiconductor layer.

[0165] In some embodiments, the first semiconductor layer is an N-type GaN layer or an N-type AlGaN layer, and the second semiconductor layer is a P-type GaN layer or a P-type AlGaN layer, that is, the material of the second semiconductor layer may be a material layer of the second conductivity type including at least two or more elements of Ga, N, As, Al, In, and P, and the first semiconductor layer may be a material layer of the first conductivity type including at least two or more elements of Ga, N, As, Al, In, and P. The conductivity types of the first semiconductor layer and the second semiconductor layer may be interchangeable.

[0166] In some embodiments, the light emitting layer includes at least one quantum well layer. The thickness of the quantum well layer is between 20 nm and 40 nm, for example, 30 nm. In some embodiments, the material of the quantum well layer is GaInP / (Al x Ga1-x ) y In 1-y P, wherein x ranges from 0.5 to 0.9 and y ranges from 0.3 to 0.5. For example, x is 0.8 and y is 0.5. In some embodiments, the relationship between x and y is that x is 1 to 2 times greater than y. In some embodiments, the light emitting layer is a multiple quantum well (MQW).

[0167] In some embodiments, one of the first semiconductor layer and the second semiconductor layer is an N-type semiconductor layer, and the other is a P-type semiconductor layer. In some embodiments, the N-type semiconductor layer further includes a doped N-type contact layer and an N-type cladding layer. The N-type cladding layer is formed on the doped N-type contact layer. The material of the N-type cladding layer is Al x In 1-x P, wherein x ranges from 0.1 to 0.5, for example, x is 0.5. In addition, in these embodiments, the thickness of the N-type cladding layer is not greater than 350 nm, for example, the thickness of the N-type cladding layer is 320 nm. The doping concentration of the N-type cladding layer is 5e 17 cm -3 To 1e 18 cm -3 In some embodiments, the N-type semiconductor layer further includes a doped N-type contact layer and an N-type cladding layer formed on the doped N-type contact layer. The material of the doped N-type contact layer is GaAs. In some embodiments, the thickness of the doped N-type contact layer is 10 nm to 30 nm. In some embodiments, the doping concentration of the doped N-type contact layer is 2e 18 cm -3 To 1e 19 cm -3 In some embodiments, the N-type semiconductor layer further includes an N-type spacer layer formed on the N-type cladding layer. The material of the N-type spacer layer is (Al x Ga 1-x ) y In 1-y P, wherein x ranges from 0.5 to 0.9 and y ranges from 0.1 to 0.5. For example, x is 0.8 and y is 0.5. In some embodiments, the relationship between x and y is that x is 1 to 2 times greater than y. The thickness of the N-type spacer layer is 50 nm to 75 nm, for example 65 nm. In some embodiments, the P-type semiconductor layer includes a P-type cladding layer and a doped P-type contact layer. The P-type cladding layer is formed on the light-emitting layer, and the doped P-type contact layer is formed on the P-type cladding layer.

[0168] In some embodiments, the material of the P-type cladding layer is Al x In 1-xP, wherein x is 0.3 to 0.5, for example, x is 0.5. In such an embodiment, the thickness of the P-type cladding layer is not greater than 380 nm, for example, the thickness of the P-type cladding layer is 360 nm.

[0169] In some embodiments, the material of the doped P-type contact layer is GaAs. The thickness of the doped P-type contact layer is 10 nm to 30 nm, for example, 20 nm.

[0170] In some embodiments, the P-type semiconductor layer further includes a P-type spacer layer formed under the P-type cladding layer, a first doped P-type transition layer formed on the P-type cladding layer, and a second doped P-type transition layer formed on the first doped P-type transition layer. In some embodiments, the material of the P-type spacer layer is (Al x Ga 1-x ) y In 1-y P, wherein x ranges from 0.5 to 0.9 and y ranges from 0.3 to 0.5. For example, x is 0.8 and y is 0.5. In some embodiments, the relationship between x and y is that x is 1 to 2 times greater than y. In some embodiments, the thickness of the P-type spacer layer is 50 nm to 70 nm, for example 65 nm.

[0171] In some embodiments, the material of the first doped P-type transition layer is (Al x Ga 1-x ) y In 1-y P, wherein x ranges from 0.1 to 0.3 and y ranges from 0.3 to 0.5. For example, x is 0.17 and y is 0.5. In some embodiments, the relationship between x and y is y is 1 to 5 times x. In some embodiments, the thickness of the first doped P-type transition layer is 20 nm to 40 nm, for example 30 nm.

[0172] In some embodiments, the material of the second doped P-type transition layer is Al x Ga 1-x As, wherein x ranges from 0.5 to 0.9, for example, x is 0.6. In some embodiments, the thickness of the second doped P-type transition layer is from 10 nm to 30 nm, for example, 20 nm.

[0173] In some embodiments, the doping concentration of the second doped P-type transition layer is greater than the doping density of the first doped P-type transition layer. The doping concentration of the doped P-type contact layer is 1 to 10 times the doping concentration of the second doped P-type transition layer.

[0174] In some embodiments, the doping concentration of the doped P-type contact layer is greater than the doping concentration of the second doped P-type transition layer. In addition, in some embodiments, the doping concentration of the second doped P-type transition layer is 2 to 4 times the doping concentration of the first doped P-type transition layer.

[0175] For example, the doping concentration of the first doped P-type transition layer is greater than 1e 18 cm -3 The doping density of the second doped P-type transition layer is 2e 18 cm -3 -4e 18 cm -3 In the range of 5e 18 cm -3 In some embodiments, the electrode polarity of the ohmic contact layer is opposite to the electrode polarity of the top conductive layer. The ohmic contact layer may be, for example, a P electrode or an anode electrode, and the top conductive layer is an electrode having a polarity opposite to that of the ohmic contact layer, such as an N electrode or a cathode electrode. In one embodiment, the ohmic contact layer, the top conductive layer and their connecting parts may be a combination of one or more such as graphene or indium tin oxide (ITO) or aluminum doped zinc oxide (AZO) or fluorine doped tin oxide (FTO) or other transparent conductive oxides (TCO).

[0176] In one embodiment, adjacent top conductive layers are connected, and all top conductive layers are connected as a whole. In some embodiments, the top conductive layer can be shared by all micro-LEDs in the micro-LED array.

[0177] In some embodiments, the electrode polarity of the ohmic contact layer is opposite to the electrode polarity of the top conductive layer. The ohmic contact layer may be, for example, a P electrode or an anode electrode, and the top conductive layer may be an electrode having a polarity opposite to that of the ohmic contact layer, such as an N electrode or a cathode electrode. In one embodiment, the ohmic contact layer, the top conductive layer and their connecting parts may be a combination of one or more such as graphene or indium tin oxide (ITO) or aluminum doped zinc oxide (AZO) or fluorine doped tin oxide (FTO) or other transparent conductive oxides (TCO).

[0178] In some embodiments, adjacent passivation isolation layers are connected, and all passivation isolation layers are connected into a whole. In one embodiment, the material of the passivation isolation layer is one or more of silicon oxide, silicon oxynitride, aluminum oxide, and silicon nitride.

[0179] In some embodiments, the microdisplay panel further comprises a current spreading structure located between the microlight emitting diodes, wherein the current spreading structure is arranged to surround the microlight emitting diodes, and the current spreading structure is configured to electrically contact the microlight emitting diodes and at least partially reflect light emitted by the microlight emitting diodes.

[0180] The current spreading structure surrounds the micro light emitting diode, and the current spreading structure is electrically connected to the micro light emitting diode.

[0181] The surface of the current spreading structure facing the micro-LED has light reflection capability, for example, it is made of metal, so that the current spreading structure can at least partially reflect the light emitted by the LED. The reflection process is that the light emitted from the light-emitting layer of the LED passes through the transparent layer (for example, the top conductive layer) thereon, and then the first part of these lights (whose emission angle is small enough so that it will not hit the current spreading structure on the side, within the preset light emission angle, such as within plus or minus 20°) is directly emitted, and the second part of these lights (whose emission angle is large enough to hit the current spreading structure on the side) hits the current spreading structure and is emitted after reflection, changing the direction of the light path to within the preset light emission angle, thereby effectively improving the light emission rate. Preferably, the proportion of light reflected by the current spreading structure to the light emitted by the LED can be, for example, 10% to 60%. By providing a current spreading structure with light reflection capability, the amount of light absorbed by the side wall can be significantly reduced, thereby significantly increasing the total light emission. At the same time, the current spreading structure can also isolate light to prevent light crosstalk between adjacent LEDs.

[0182] By arranging the current spreading structure to surround the top conductive layer of the micro-light emitting diode in an electrical contact manner, the electrical contact area between the current spreading structure and the micro-light emitting diode can be significantly increased, so that the active layer (light-emitting layer) of the micro-light emitting diode can emit light more evenly, effectively avoiding the situation where only the electrical contact part or its vicinity emits light or the electrical contact part or its vicinity emits light at a high brightness.

[0183] The size of the bottom of the current spreading structure is larger than the size of the top. Since the bottoms of adjacent current spreading structures are connected, the longitudinal sections of the two adjacent current spreading structures present a bifurcated peak shape.

[0184] The bottoms of adjacent current spreading structures are connected, and all current spreading structures are connected as a whole. For a micro-LED whose top view shape (i.e., cross-sectional shape) is a circle, the top view shape of the overall current spreading structure is a grid shape remaining after removing the circle. In other embodiments, the top view shape of the micro-LED may also be other appropriate shapes, such as a rectangle, a square, or a regular polygon. The top view shape of the overall current spreading structure may also be a shape remaining after removing other appropriate shapes, such as a grid shape remaining after removing a rectangle, a square, or a polygon.

[0185] In an embodiment of the present invention, the bottom of the current spreading structure is lower than the epitaxial layer of the micro light emitting diode.

[0186] In the embodiment of the present invention, the top of the current spreading structure may be higher than the top of the epitaxial layer; the top of the current spreading structure may also be flush with the top of the epitaxial layer; the top of the current spreading structure may also be lower than the top of the epitaxial layer (for example, slightly lower than the top of the epitaxial layer by 0-1 micron). One, two or three of the above situations may exist simultaneously in a chip.

[0187] Preferably, the top of the current spreading structure is higher than the top of the epitaxial layer of the micro-LED. By making the top of the current spreading structure higher than the height of the top plane of the epitaxial layer of the micro-LED, a higher current spreading structure can be obtained, further improving the chance of light reflection and increasing the light output rate.

[0188] In other embodiments, the number of current spreading structures may also be 1 / 4 or 1 / 9 of the number of micro-LEDs, and each current spreading structure surrounds 4 micro-LEDs or 9 micro-LEDs without limitation.

[0189] The current spreading structure can increase the current spreading between adjacent micro-LEDs, reduce the resistance between adjacent micro-LEDs, and reduce the loss. The current spreading structure can make the current spread quickly and evenly to all micro-LEDs.

[0190] In an embodiment of the present invention, the current spreading structure may be a multi-layer structure, and the current spreading structure includes one or more main metal layers. In an embodiment of the present invention, the material of the main metal layer may be one or more of Pt, Au, Al, and Ag.

[0191] In some embodiments, the current spreading structure may further include: isolation layers corresponding to each main metal layer one by one; wherein the isolation layers and the main metal layers are arranged alternately, and each main metal layer is located on the corresponding isolation layer.

[0192] By using an isolation layer corresponding to each main metal layer one by one, and the isolation layer and the main metal layer are arranged in an alternating manner, and each main metal layer is located on the corresponding isolation layer, the influence of electromigration in the current spreading structure can be effectively suppressed by setting the isolation layer, especially when the density of micro-LEDs in the micro-LED display chip is relatively high, the possibility of increasing the height of the current spreading structure can be obtained by setting the isolation layer, and then the light extraction rate can be further improved by a higher current spreading structure. Furthermore, the isolation layer may include: a titanium (Ti) metal layer. It should be noted that the material of the isolation layer may also include other appropriate materials, such as titanium nitride (TiN).

[0193] In some embodiments, the current spreading structure may further include: an adhesion layer, located at the bottom layer of the current spreading structure, and an isolation layer and a main metal layer are located above the adhesion layer. An adhesion layer is formed between the micro-LEDs in the adhesion layer, and the isolation layer and the main metal layer are located on the adhesion layer. The adhesion effect of the adhesion layer can effectively improve the bottom stability of the current spreading structure, especially when the density of micro-LEDs in the micro-LED display chip is large. By setting the adhesion layer, it is possible to increase the height of the current spreading structure, thereby further improving the light output rate through a higher current spreading structure. Furthermore, the adhesion layer may include: a chromium (Cr) metal layer. It should be noted that the material of the adhesion layer may also include other appropriate materials, such as one or more of the following: titanium (Ti), titanium nitride (TiN), and tungsten (W).

[0194] In an embodiment of the present invention, the current spreading structure may further include: an anti-diffusion layer corresponding to the isolation layer one by one, and each isolation layer is located on the corresponding anti-diffusion layer. By forming an anti-diffusion layer corresponding to the isolation layer one by one, and each isolation layer is located on the corresponding anti-diffusion layer, the stability of the current spreading structure can be improved by the characteristics of high hardness and good corrosion resistance of the anti-diffusion layer, especially in the case where the density of micro-light-emitting diodes in the micro-light-emitting diode display chip is large, it is possible to increase the height of the current spreading structure by setting the anti-diffusion layer, and then further improve the light output rate through a higher current spreading structure. The anti-diffusion layer may include: a platinum (Pt) metal layer and a nickel (Ni) metal layer. It should be pointed out that the anti-diffusion layer can be a single-layer platinum metal layer, a single-layer nickel metal layer, or a stack of a single-layer platinum metal layer and a single-layer nickel metal layer.

[0195] In some embodiments, the microdisplay panel further includes a microlens array. The microlens array is disposed above the microlight emitting diode array, wherein at least one microlens is disposed on the surface of the conductive layer at the top of the microlight emitting diode, and the horizontal profile of the microlens is greater than the maximum horizontal profile of the microlight emitting diode. The microlens is mainly used to converge and / or collimate light, for example, by adjusting the thickness, curvature and other parameters of the microlens so that the focus of the microlens is located in the epitaxial layer of the microlight emitting diode. In some embodiments, the microlenses of the microlens array correspond one-to-one to the epitaxial layer. In some embodiments, examples of microlenses include spherical microlenses, aspherical microlenses, Fresnal microlenses and cylindrical microlenses.

[0196] In an embodiment of the present invention, there is a gap between adjacent microlenses. In an embodiment of the present invention, the bottom of the gap is higher than the top of the epitaxial layer. In another embodiment of the present invention, the bottom of the gap is lower than the top of the epitaxial layer and higher than the bottom of the epitaxial layer. In another embodiment of the present invention, the bottom of the gap is located above the current spreading structure. Specifically, the gap is located between two adjacent current spreading structures (i.e., between the bifurcation peaks).

[0197] In addition, there may be an air gap inside the microlens. Each lens may have multiple air gaps, and the size and length of each air gap are the same or different. At the same time, in the same chip, the number of air gaps and / or the position and / or size of the air gaps in different microlenses may be the same or different. In some embodiments of the present invention, the air gap is located at the edge of the microlens, specifically, for example, it may be located on both sides of the epitaxial layer, preferably, it is located between the epitaxial layer and the current expansion structure. At the same time, in some embodiments, the top of the air gap is higher than the top of the epitaxial layer, and the bottom thereof may be higher than the top of the epitaxial layer or lower than the top of the epitaxial layer. In some embodiments, the bottom of the air gap is higher than the top of the current expansion structure. In some other embodiments, the bottom of the air gap is lower than the top of the current expansion structure. It should be noted that in other embodiments of the present invention, there may be no air gap inside the microlens.

[0198] Although some embodiments of the present invention have been described in this application document, it will be appreciated by those skilled in the art that these embodiments are merely shown as examples. Those skilled in the art may conceive of numerous variations, alternatives, and improvements under the teachings of the present invention without departing from the scope of the present invention. The appended claims are intended to define the scope of the present invention and to cover methods and structures within the scope of these claims themselves and their equivalents.

Claims

1. A micro display projection device, characterized in that: include: A light combining structure, comprising a first light emitting surface and a plurality of first light receiving surfaces for receiving light, capable of combining image light beams passing through the plurality of first light receiving surfaces and emitting the image light beams from the first light emitting surface; A plurality of micro display panels, each of which has a light emitting surface, emitting light of one color from the light emitting surface; each of the micro display panels comprises a pixel array; the light emitting surface of the micro display panel is arranged relative to the first light receiving surface; the plurality of micro display panels are arranged in one-to-one correspondence with the plurality of first light receiving surfaces of the light combining structure; A plurality of metasurface lens structures are arranged in one-to-one correspondence with a plurality of microdisplay panels; each metasurface lens structure is arranged corresponding to one side of the light-emitting surface of the corresponding microdisplay panel; Furthermore, it is sandwiched between the micro display panel and the light combining structure.

2. The micro display projection device as claimed in claim 1, characterized in that: The metasurface lens structure is made of metamaterial, and the metamaterial includes at least one of single crystal silicon, silicon oxide, aluminum oxide, and titanium oxide.

3. The micro display projection device according to claim 1, characterized in that: A plurality of the super-surface lens structures are integrally packaged.

4. The micro display projection device according to claim 1, characterized in that: The metasurface lens structure includes a plurality of atomic structures of the same shape.

5. The micro display projection device according to claim 4, characterized in that: The shape of the atomic structure includes at least one of a cylinder, a cube, a snowflake, a polyhedron, a truncated cone, and an irregular column.

6. The micro display projection device according to claim 5, characterized in that: The cylindrical diameter is greater than or equal to 50 nanometers and less than or equal to 200 nanometers, and the height is greater than or equal to 300 nanometers and less than or equal to 2000 nanometers.

7. The micro display projection device according to claim 5, characterized in that: The width of the cube is greater than or equal to 50 nanometers and less than or equal to 200 nanometers, and the height is greater than or equal to 300 nanometers and less than or equal to 2000 nanometers.

8. The micro display projection device according to claim 1, characterized in that: The distance from the super-surface lens structure to the light-combining structure is greater than 0.2 mm, and the distance from the super-surface lens structure to the micro-display panel is greater than or equal to 0.1 mm and less than or equal to 0.3 mm.

9. The micro display projection device according to claim 1, characterized in that: The metasurface lens structure includes a plurality of metasurface lens substructures stacked at a certain interval; each metasurface lens substructure includes a second light-emitting surface and a second light-collecting surface; the second light-emitting surface of each metasurface lens substructure faces the first light-collecting surface of the corresponding light-combining structure, and the second light-collecting surface of each metasurface lens substructure faces the light-emitting surface of the corresponding microdisplay panel.

10. The micro display projection device according to claim 9, characterized in that: The thickness of the metasurface lens substructure is greater than or equal to 0.2 mm and less than or equal to 0.5 mm.

11. The micro display projection device according to claim 1, characterized in that: The metasurface lens structure and the micro display panel are fixedly connected; the fixed connection includes at least one of a gluing connection, a bonding connection, and a clamping connection.

12. The micro display projection device according to claim 1, characterized in that: The pixel array in the micro display panel is a micro light emitting diode array; the light combining structure is a light combining prism.

13. The micro display projection device according to claim 12, characterized in that: The micro display panel comprises: Driver backplane, including: dielectric layer; A driving circuit, located in the dielectric layer, and a driving electrode, located in the dielectric layer, with at least an upper surface of the driving electrode exposed from the dielectric layer, the driving electrode being electrically connected to the driving circuit; and The micro light emitting diode array is arranged on the driving back plate, and each micro light emitting diode in the micro light emitting diode array is electrically connected to the driving electrode of the driving back plate.

14. The micro display projection device according to claim 13, characterized in that: The micro light emitting diode includes a first semiconductor layer, a second semiconductor layer, and a light emitting layer formed between the first semiconductor layer and the second semiconductor layer, the first semiconductor layer is of a different conductivity type from the second semiconductor layer, and the light emitting layer includes a plurality of stacked layers.

15. A display device, characterized in that: It comprises the micro display projection device as claimed in claim 1.

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