A microlens collimating structure and micro light emitting diode

Abstract

The present application belongs to the field of Micro-LED micro-nano optical light field control technology, and relates to a microlens collimation structure and a micro light emitting diode. The microlens collimation structure includes: a first aperture set on the periphery of the display chip, a first microlens stacked on the side of the first aperture away from the Micro-LED backplane, a base layer and a second microlens; wherein the first microlens is a plano-concave lens, and its surface close to the first aperture is a concave high-order aspheric surface, and the second microlens is a plano-convex lens, and its surface away from the base layer is a convex high-order aspheric surface. The light hole of the first aperture, the sub-mirror centers of the first microlens and the second microlens are all aligned with the center of the display chip. The present application uses the first aperture to eliminate stray light, and uses the concave high-order aspheric surface on the first microlens and the convex high-order aspheric surface on the second microlens to focus the light beam to achieve light beam collimation, which not only avoids beam crosstalk between adjacent display chips, but also reduces the beam divergence angle.

Description

Technical Field

[0001] The present invention relates to the field of Micro-LED micro-nano optical light field control technology, and in particular to a microlens collimation structure and a micro light emitting diode. Background Art

[0002] With technological advancements, projection displays are developing towards miniaturization, high brightness, low energy consumption, and high resolution, and micro-projection display devices are gaining increasing attention. Common digital light processing (DLP), liquid crystal display (LCD), and liquid crystal on silicon (LCOS) projection systems require an illumination source to illuminate a display array device, which then achieves full-color display. Improving the system's light energy utilization and image plane illumination uniformity requires complex and large optical structures to shape the illumination beam, making it difficult to meet the demands of miniaturization and lightweight projection display systems.

[0003] Micro-LEDs, as an actively luminous display device, combine lighting and display functions. By densely arranging multiple micron-scale Micro-LED display chips in a small area, they achieve high-resolution and high-brightness displays, making it possible to realize high-resolution, lightweight, miniaturized and low-loss micro-projection systems. However, due to the very small size of the Micro-LED display chips in Micro-LEDs, the light beams can easily scatter and diffuse at the exit of the display chip, making it difficult to accurately focus and control, resulting in a large light beam divergence angle. At the same time, the light beams between adjacent display chips will interfere with each other, resulting in inter-pixel light beam crosstalk, resulting in low clarity and contrast of the displayed image.

[0004] To sum up, Micro-LED has the problems of large beam divergence angle and beam crosstalk between pixels, which leads to low clarity and contrast of the imaging surface. Summary of the Invention

[0005] To this end, the technical problem to be solved by this application is to overcome the problems of large beam divergence angle and beam crosstalk between pixels in the Micro-LED in the prior art, which lead to low clarity and contrast of the imaging surface.

[0006] To solve the above technical problems, the present application provides a microlens collimating structure, comprising:

[0007] The first aperture is arranged on the periphery of the Micro-LED display chip, and its light hole is aligned with the center of the Micro-LED display chip;

[0008] A first microlens is disposed on the surface of the first aperture away from the Micro-LED backplane, with the center of its sub-lens aligned with the center of the Micro-LED display chip; the first microlens is a plano-concave lens, with its concave surface disposed on the side close to the first aperture and its flat surface disposed on the side away from the first aperture;

[0009] A base layer is provided on a surface of the first microlens away from the first aperture;

[0010] A second microlens is disposed on a surface of the substrate layer away from the first microlens, with the center of the sub-lens aligned with the center of the Micro-LED display chip; the second microlens is a plano-convex lens, with its flat surface disposed on the side close to the substrate layer and its convex surface disposed on the side away from the substrate layer;

[0011] Wherein, the concave surface of the first microlens and the convex surface of the second microlens are both high-order aspherical surfaces.

[0012] In the present application, a first aperture is used to eliminate stray light, thereby avoiding beam crosstalk between adjacent Micro-LED display chips; by arranging a first microlens, a base layer, and a second microlens on the first aperture, the concave high-order aspheric surface on the first microlens and the convex high-order aspheric surface on the second microlens are used to converge the light beams to achieve beam collimation, which not only avoids beam crosstalk between adjacent display chips, but also reduces the beam divergence angle, thereby improving imaging clarity and contrast.

[0013] Preferably, the surface expression of the high-order aspheric surface is:

[0014] ,

[0015] in, Represents the vector height at the a-th sampling point on the high-order aspheric surface; , Indicates the radius of curvature of the vertex of a high-order aspheric surface; represents the cone coefficient; Represents the lens radius at the a-th sampling point on the high-order aspheric surface, , Represents the coordinates of the a-th sampling point on the high-order aspheric surface; , Indicates the number of sampling points on the high-order aspheric surface; is the second-order coefficient of the high-order aspheric surface; is the 4th order coefficient of the high-order aspheric surface; is the 6th-order coefficient of the high-order aspheric surface; is the 8th-order coefficient of the high-order aspheric surface.

[0016] In this application, an 8th-order high-order aspheric surface is used, which can more accurately adjust the collimation characteristics of the light beam compared to low-order high-order aspheric surfaces, thereby achieving better collimation of the light beam and reducing the diffusion of the light spot, thereby optimizing the beam quality. At the same time, compared to high-order high-order aspheric surfaces, it has lower processing difficulty and production cost, thus balancing the collimation performance and production cost of the lens.

[0017] Preferably, when the high-order aspheric surface is concave, the value range of the second-order coefficient in its surface expression is ; The value range of the 4th order coefficient is ; The value range of the 6th order coefficient is ; The value range of the 8th order coefficient is ;

[0018] When the high-order aspheric surface is convex, the range of the coefficient of the second-order term in its surface expression is ; The value range of the 4th order coefficient is ; The value range of the 6th order coefficient is ; The value range of the 8th order coefficient is .

[0019] In the present application, by controlling the coefficients of the various orders of the concave high-order aspheric surface of the first microlens and the convex high-order aspheric surface of the second microlens, the curvature of the first microlens and the second microlens changes from the center to the edge of the lens in the following trend: increase → decrease → increase → decrease, thereby achieving more uniform focus of the light beam in the lens, reducing the beam divergence angle, and enhancing the collimation effect.

[0020] Preferably, the refractive index of the base layer is greater than the refractive index of the first microlens and the refractive index of the second microlens.

[0021] In the present application, by controlling the refractive indices of the first microlens, the base layer, and the second microlens, the light beam is continuously refracted and tends to be parallel during the transmission process among the first microlens, the base layer, and the second microlens, thereby further reducing the divergence angle of the light beam.

[0022] Preferably, the light-clearance diameter of the concave surface of the first microlens is less than three times the diameter of the Micro-LED display chip;

[0023] The light-clearance diameter of the convex surface of the second microlens is less than four times the diameter of the Micro-LED display chip.

[0024] In this application, by controlling the size of the light-clearance aperture of the concave surface of the first microlens and the light-clearance aperture of the convex surface of the second microlens, a microlens collimating structure is configured to collimate the light beam emitted by only one Micro-LED display chip, ensuring that the light beam of each Micro-LED display chip is optimally collimated, avoiding optical interference between adjacent display chips, and thereby maximizing the performance of each display chip.

[0025] Preferably, the clear aperture of the first aperture is equal to the clear aperture of the concave surface of the first microlens.

[0026] Preferably, it also includes:

[0027] The second aperture is arranged on the periphery of the second microlens, and the light hole of the second aperture is aligned with the center of the Micro-LED display chip.

[0028] In the present application, the second aperture is used to eliminate stray light from the light-emitting surface of the second microlens, further eliminating light beam crosstalk between adjacent display chips, thereby improving the clarity and contrast of the imaging surface.

[0029] Preferably, the clear aperture of the second aperture is equal to the clear aperture of the second microlens plane;

[0030] The height of the second aperture is equal to one sixth of the thickness of the second microlens.

[0031] In the present application, by controlling the clear aperture of the second aperture to match the clear aperture of the second microlens plane, the transmission efficiency of the light beam between the second microlens and the second aperture can be ensured, light loss can be reduced, and the intensity and stability of the light beam can be maintained.

[0032] Preferably, the material of the base layer is one of optical plastic, glass or biaxially oriented polypropylene film.

[0033] The present application also provides a micro light emitting diode, comprising:

[0034] Micro-LED display chip array;

[0035] A plurality of the above-mentioned micro-lens collimating structures are respectively arranged on each Micro-LED display chip in the Micro-LED display chip array.

[0036] The microlens collimating structure provided in the present application includes: a first aperture arranged on the periphery of a Micro-LED display chip, a first microlens stacked on the surface of the first aperture away from the Micro-LED backplane, a base layer, and a second microlens; wherein the first microlens is a plano-concave lens, and its surface close to the first aperture is a concave high-order aspheric surface; the second microlens is a plano-convex lens, and its surface away from the base layer is a convex high-order aspheric surface; the light hole of the first aperture, the center of the sub-mirror of the first microlens, and the center of the sub-mirror of the second microlens are all aligned with the center of the display chip. Using the microlens collimation structure designed in this solution, the light beam emitted by the Micro-LED display chip enters the first microlens through the light hole of the first aperture, and the first aperture is used to eliminate stray light and avoid beam crosstalk between adjacent display chips; a first microlens is set on the first aperture, and the concave high-order aspheric surface on the first microlens is used to converge the incident light beam to reduce the large divergence angle. Then the light beam passes through the base layer and enters the second microlens, and the convex high-order aspheric surface of the second microlens is used to converge the light beam again and then emit it, further reducing the large divergence angle of the light beam to achieve beam collimation; this not only avoids the problem of beam crosstalk between adjacent display chips, but also reduces the beam divergence angle, thereby improving the clarity and contrast of the imaging surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0038] Figure 1 A schematic diagram of a microlens collimating structure provided in this application;

[0039] Figure 2 A top view of a Micro-LED display chip array provided in this application;

[0040] Figure 3 A schematic diagram of the micro light emitting diode structure provided for this application;

[0041] Figure 4 A schematic cross-sectional diagram of the intensity of the collimated light-emitting surface of the micro-light-emitting diode provided in this application;

[0042] Explanation of the accompanying drawings in the specification: 1. Micro-LED display chip; 2. Micro-LED backplane; 3. First aperture; 4. First microlens; 5. Base layer; 6. Second microlens; 7. Second aperture. DETAILED DESCRIPTION

[0043] The present application will be further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present application and implement it, but the embodiments are not intended to limit the present application.

[0044] See also Figure 1 , Figure 1 A schematic diagram of a microlens collimation structure provided in an embodiment of the present application includes: a first aperture 3 arranged around the periphery of a Micro-LED display chip 1, and a first microlens 4, a base layer 5, and a second microlens 6 stacked on the surface of the first aperture 3 away from the Micro-LED backplane 2.

[0045] The first aperture 3 is sleeved on the periphery of the Micro-LED display chip 1 , and the light hole thereof is aligned with the center of the Micro-LED display chip 1 .

[0046] The first microlens 4 is arranged on the surface of the first aperture 3 away from the Micro-LED backplane 2, and the center of its sub-lens is aligned with the center of the Micro-LED display chip 1; wherein, the first microlens 4 is a plano-concave lens, whose concave surface is arranged on the side close to the first aperture 3, and its flat surface is arranged on the side away from the first aperture 3.

[0047] The base layer 5 is arranged on the surface of the first microlens 4 away from the first aperture 3 .

[0048] The second microlens 6 is arranged on the surface of the base layer 5 away from the first microlens 4, and the center of its sub-lens is aligned with the center of the Micro-LED display chip 1. The second microlens 6 is a plano-convex lens, with its flat surface arranged on the side close to the base layer 5 and its convex surface arranged on the side away from the base layer 5.

[0049] The concave surface of the first microlens 4 and the convex surface of the second microlens 6 are both high-order aspherical surfaces.

[0050] In this embodiment, a microlens collimating structure is designed on the light-emitting side of the Micro-LED display chip. The light beam emitted by the Micro-LED display chip enters the first microlens through the light hole of the first aperture. The first aperture is used to eliminate stray light and avoid beam crosstalk between adjacent display chips. The concave high-order aspheric surface on the first microlens is used to converge the incident light beam, reducing the large divergence angle. The light beam then passes through the base layer and enters the second microlens. The convex high-order aspheric surface of the second microlens is used to converge the light beam again and then emit it, further reducing the large divergence angle of the light beam, thereby achieving beam collimation. This not only avoids the problem of beam crosstalk between adjacent display chips, but also reduces the beam divergence angle, thereby improving the clarity and contrast of the imaging surface.

[0051] Specifically, by changing the specific shapes of the concave high-order aspheric surface of the first microlens 4 and the specific shapes of the convex high-order aspheric surface of the second microlens 6, the collimation effect of the first microlens 4 and the second microlens 6 on the light beam can be changed.

[0052] In the present application, the surface shape expression of the high-order aspheric surface is used to determine the specific shapes of the concave high-order aspheric surface of the first microlens 4 and the convex high-order aspheric surface of the second microlens 6. The surface shape expression of the high-order aspheric surface in the embodiment of the present application is:

[0053] ,

[0054] in, Represents the vector height at the a-th sampling point on the high-order aspheric surface; , Indicates the radius of curvature of the vertex of a high-order aspheric surface; represents the cone coefficient; Represents the lens radius at the a-th sampling point on the high-order aspheric surface, , Represents the coordinates of the a-th sampling point on the high-order aspheric surface; , Indicates the number of sampling points on the high-order aspheric surface; is the second-order coefficient of the high-order aspheric surface; is the 4th order coefficient of the high-order aspheric surface; is the 6th-order coefficient of the high-order aspheric surface; is the 8th-order coefficient of the high-order aspheric surface.

[0055] The specific shape of the aspheric surface can be obtained by determining the order of the aspheric surface and the coefficient of each order term. Since high-order aspheric surfaces can more accurately adjust the collimation characteristics of the light beam than low-order aspheric surfaces, the collimation effect of the light beam is better, the diffusion of the light spot is reduced, and the beam quality is optimized. However, as the order term increases, the processing difficulty of the aspheric surface becomes increasingly higher, and the production cost also increases accordingly. Therefore, in the embodiment of the present application, the concave high-order aspheric surface of the first microlens 4 and the convex high-order aspheric surface of the second microlens 6 both adopt the 8th order term to balance the collimation performance and production cost of the lens.

[0056] In one embodiment, the second-order coefficient of the concave high-order aspheric surface of the first microlens 4 ranges from The value range of the 4th order coefficient of the concave high-order aspheric surface of the first microlens 4 is The value range of the 6th order coefficient of the concave high-order aspheric surface of the first microlens 4 is The 8th order coefficient of the concave high-order aspheric surface of the first microlens 4 is in the range of .

[0057] The second order coefficient of the convex high-order aspheric surface of the second microlens 6 is in the range of The 4th order coefficient of the convex high-order aspheric surface of the second microlens 6 is in the range of The 6th order coefficient of the convex high-order aspheric surface of the second microlens 6 is in the range of The 8th order coefficient of the convex high-order aspheric surface of the second microlens 6 is in the range of .

[0058] By limiting the order coefficients of the higher-order aspheric surfaces of the first microlens 4 and the second microlens 6, the curvature of the first microlens 4 and the second microlens 6 changes from the center to the edge in the following trend: increase → decrease → increase → decrease, thereby achieving more uniform focus of the light beam in the lens, reducing the beam divergence angle, and enhancing the collimation effect.

[0059] Preferably, the refractive index of the base layer 5 is greater than the refractive index of the first microlens 4 and the refractive index of the second microlens 6; when the light beam enters the first microlens 4, the angle between the light beam and the optical axis decreases due to the increase in refractive index and the concave high-order aspheric surface on the light beam converging the light beam; when the light beam enters the base layer 5 from the first microlens 4, the increase in refractive index causes the light beam to refract further and bend toward the optical axis; when the light beam enters the second microlens 6 from the base layer 5, the decrease in refractive index causes the light beam to refract and bend away from the optical axis. Therefore, through the change in the refractive index of the first microlens 4, the base layer 5, and the second microlens 6, combined with the concave high-order aspheric surface of the first microlens 4, the angle between the light beam and the optical axis gradually decreases and tends to be parallel, thereby reducing the divergence angle of the light beam.

[0060] Optionally, in some embodiments, the material of the base layer 5 may be one of optical plastic, glass, or biaxially oriented polypropylene film (BOPP).

[0061] In a specific embodiment of the present application, the material of the base layer 5 is a biaxially oriented polypropylene film. This is because the biaxially oriented polypropylene film has good impact resistance, and due to the relatively simple processing technology, its production cost and processing cost are lower than optical plastics and glass.

[0062] In one embodiment, the light-clearing aperture of the concave surface of the first microlens 4 is less than three times the aperture of the Micro-LED display chip 1; the light-clearing aperture of the convex surface of the second microlens 6 is less than four times the aperture of the Micro-LED display chip 1; the light-clearing aperture of the first aperture 3 is equal to the light-clearing aperture of the concave surface of the first microlens 4; so that one microlens collimating structure only collimates the light beam emitted by one Micro-LED display chip, ensuring that the light beam of each Micro-LED display chip is optimally collimated, avoiding optical interference between adjacent display chips, and thereby maximizing the performance of each display chip.

[0063] like Figure 1 As shown, in some embodiments of the present application, the microlens collimating structure further includes a second aperture 7; the second aperture 7 is arranged on the periphery of the second microlens 6, and its light hole is aligned with the center of the Micro-LED display chip 1.

[0064] The second aperture 7 is used to eliminate stray light on the light-emitting surface of the second microlens 6, further eliminating the light beam crosstalk between adjacent display chips, and further improving the clarity and contrast of the imaging surface.

[0065] In one embodiment, the clear aperture of the second aperture 7 is equal to the clear aperture of the second microlens 6 plane; the height of the second aperture 7 is equal to one-sixth of the thickness of the second microlens 6; by ensuring that the clear aperture of the second aperture 7 matches the clear aperture of the second microlens 6 plane, the transmission efficiency of the light beam between the second microlens 6 and the second aperture 7 can be ensured, light loss can be reduced, and the intensity and stability of the light beam can be maintained.

[0066] Based on the microlens collimating structure provided in the above embodiment, the embodiment of the present application further provides a micro light emitting diode, which includes:

[0067] Micro-LED display chip array;

[0068] A plurality of the aforementioned micro-lens collimating structures are respectively disposed on each Micro-LED display chip in the Micro-LED display chip array.

[0069] For example, Figure 2 The figure shows a Micro-LED display chip array, which is composed of multiple Micro-LED display chips arranged in an array. Each Micro-LED display chip is 5 ×5 to 10 ×10 The beam divergence angle is between 90° and 120°. Figure 3 Shown in Figure 2 The micro-LEDs are obtained by setting a micro-lens collimating structure on the Micro-LED display chip array shown.

[0070] The technical solution of the present application will be described in detail below in conjunction with a plurality of embodiments. However, it should be understood that the following embodiments are only for explaining and illustrating the technical solution but do not limit the scope of the present application. Example 1

[0071] This embodiment provides a microlens collimating structure, which includes a first aperture arranged around the periphery of a Micro-LED display chip, a first microlens, a base layer, and a second microlens stacked on a side of the first aperture away from the Micro-LED backplane, and a second aperture arranged around the periphery of the second microlens.

[0072] The material of the base layer is biaxially oriented polypropylene film.

[0073] The second-order coefficient of the concave high-order aspheric surface of the first microlens is , the coefficient of the 4th order term is , the coefficient of the 6th order term is , the coefficient of the 8th order term is , the radius of curvature of the vertex is .

[0074] The second-order coefficient of the convex high-order aspheric surface of the second microlens is , the coefficient of the 4th order term is , the coefficient of the 6th order term is , the coefficient of the 8th order term is , the radius of curvature of the vertex is . Example 2

[0075] This embodiment provides a microlens collimating structure, which includes a first aperture arranged around the periphery of a Micro-LED display chip, a first microlens, a base layer, and a second microlens stacked on a side of the first aperture away from the Micro-LED backplane, and a second aperture arranged around the periphery of the second microlens.

[0076] The material of the base layer is biaxially oriented polypropylene film.

[0077] The second-order coefficient of the concave high-order aspheric surface of the first microlens is , the coefficient of the 4th order term is , the coefficient of the 6th order term is , the coefficient of the 8th order term is , the radius of curvature of the vertex is .

[0078] The second-order coefficient of the convex high-order aspheric surface of the second microlens is , the coefficient of the 4th order term is , the coefficient of the 6th order term is , the coefficient of the 8th order term is , the radius of curvature of the vertex is .

[0079] Specifically, the specific parameters of the microlens collimating structure provided in this embodiment are shown in Table 1:

[0080] Table 1

[0081] Serial number Radius of curvature thickness Micro-LED display chip 1 unlimited 0 First aperture 3 unlimited 3.0E-003 The first microlens 4 is close to the first aperture surface 1.100E-003 4.60E-003 The first microlens 4 is far away from the first aperture surface unlimited 0 The base layer 5 is close to the surface of the first microlens unlimited 5.00E-003 The base layer 5 is away from the first microlens surface unlimited 0 The second microlens 6 is close to the surface of the base layer unlimited 0.027 The second microlens 6 is far away from the surface of the substrate layer -0.0141 0 Example 3

[0082] This embodiment provides a microlens collimating structure, which includes a first aperture arranged around the periphery of a Micro-LED display chip, a first microlens, a base layer, and a second microlens stacked on a side of the first aperture away from the Micro-LED backplane, and a second aperture arranged around the periphery of the second microlens.

[0083] The material of the base layer is biaxially oriented polypropylene film.

[0084] The second-order coefficient of the concave high-order aspheric surface of the first microlens is , the coefficient of the 4th order term is , the coefficient of the 6th order term is , the coefficient of the 8th order term is , the radius of curvature of the vertex is .

[0085] The second-order coefficient of the convex high-order aspheric surface of the second microlens is , the coefficient of the 4th order term is , the coefficient of the 6th order term is , the coefficient of the 8th order term is , the radius of curvature of the vertex is .

[0086] This application utilizes the micro-lens collimating structures provided in the above-mentioned embodiments 1 to 3 to be set on each Micro-LED display chip in the Micro-LED display array (the size of each display chip is 10 ×10 , the beam divergence angle is 120°), and micro-light emitting diodes of the same specifications are obtained, and the beam divergence angle and energy utilization rate of each micro-light emitting diode are tested respectively.

[0087] like Figure 4 The figure shows a schematic diagram of the intensity cross-section of the collimated light-emitting surface of the micro-light-emitting diode obtained based on the micro-lens collimating structure provided in Example 2. It can be seen from the figure that the micro-lens collimating structure provided in the present application can reduce the light beam divergence angle from 120° to within ±15°, and its energy utilization rate is 84.7%; the light beam divergence angles of the micro-diodes obtained based on the lens collimating structures provided in Examples 1 and 3 are both within ±20°, and the energy utilization rates are both greater than 80%; this shows that the micro-lens collimating structure provided in the present application can reduce the light beam divergence angle while reducing the optical crosstalk problem between adjacent Micro-LED display chips, has a good light beam collimation effect, and fully improves the imaging clarity and contrast of the micro-light-emitting diode.

[0088] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A microlens collimating structure, characterized in that: include: The first aperture is arranged on the periphery of the Micro-LED display chip, and the light hole thereof is aligned with the center of the Micro-LED display chip; A first microlens is arranged on the surface of the first aperture away from the Micro-LED backplane, and the center of the sub-lens is aligned with the center of the Micro-LED display chip; the first microlens is a plano-concave lens, the concave surface of which is arranged on the side close to the first aperture, and the flat surface of which is arranged on the side away from the first aperture; A base layer is provided on a surface of the first microlens away from the first aperture; A second microlens is arranged on the surface of the substrate layer away from the first microlens, and the center of the sub-lens is aligned with the center of the Micro-LED display chip; the second microlens is a plano-convex lens, the plane of which is arranged on the side close to the substrate layer, and the convex surface of which is arranged on the side away from the substrate layer; Wherein, the concave surface of the first microlens and the convex surface of the second microlens are both high-order aspheric surfaces, and the surface shape expression of the high-order aspheric surface is: ， in, Represents the vector height at the a-th sampling point on the high-order aspheric surface; , Represents the radius of curvature of the vertex of a high-order aspheric surface; represents the cone coefficient; represents the lens radius at the a-th sampling point on the high-order aspheric surface, , Represents the coordinates of the a-th sampling point on the high-order aspherical surface; , Indicates the number of sampling points on the high-order aspherical surface; is the second-order coefficient of the high-order aspheric surface; is the 4th order coefficient of the high-order aspheric surface; is the 6th order coefficient of the high-order aspheric surface; is the 8th order coefficient of the high-order aspheric surface.

2. The microlens collimating structure according to claim 1, characterized in that: When the high-order aspheric surface is concave, the value range of the second-order coefficient in its surface expression is ; The value range of the coefficient of the 4th order term is ; The value range of the 6th order coefficient is ; The value range of the 8th order coefficient is ; When the high-order aspheric surface is convex, the value range of the second-order coefficient in its surface expression is ; The value range of the 4th order coefficient is ; The value range of the 6th order coefficient is ; The value range of the 8th order coefficient is .

3. The microlens collimating structure according to claim 1, characterized in that: The refractive index of the base layer is greater than the refractive index of the first microlens and the refractive index of the second microlens.

4. The microlens collimating structure according to claim 1, characterized in that: The aperture of the concave surface of the first microlens is less than three times the aperture of the Micro-LED display chip; The light-clearance diameter of the convex surface of the second microlens is less than four times the diameter of the Micro-LED display chip.

5. The microlens collimating structure according to claim 1, characterized in that: The light aperture of the first aperture is equal to the light aperture of the concave surface of the first microlens.

6. The microlens collimating structure according to claim 1, characterized in that: Also includes: The second aperture is sleeved on the periphery of the second microlens, and the light hole of the second aperture is aligned with the center of the Micro-LED display chip.

7. The microlens collimating structure according to claim 6, characterized in that: The clear aperture of the second aperture is equal to the clear aperture of the second microlens plane; The height of the second aperture is equal to one sixth of the thickness of the second microlens.

8. The microlens collimating structure according to claim 1, characterized in that: The material of the base layer is one of optical plastic, glass or biaxially oriented polypropylene film.

9. A micro light emitting diode, characterized in that: include: Micro-LED display chip array; A plurality of microlens collimating structures according to any one of claims 1 to 8 are respectively arranged on each Micro-LED display chip in the Micro-LED display chip array.

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