Micro-LED lighting device with combination of reflection cup and lens and preparation method of Micro-LED lighting device

Abstract

The invention provides a Micro-LED lighting device with a reflection cup and lens combination and a preparation method of the Micro-LED lighting device. The lighting device comprises a transparent substrate, a Fresnel lens array, a reflection cup array and a Micro-LED chip. The reflection cups and the Fresnel lenses are in one-to-one correspondence and are coaxially arranged; the diameter range of the first opening of the reflection cup is 5-15 [mu] m, and the radius range of the Fresnel lens is 10-25 [mu] m; parameters of the paraboloid of the reflection cup meet the condition that the range of the ratio of the focal length f to the size of the chip is 5-20. A combined structure of the reflection cup and the Fresnel lens is adopted to provide collimation and high efficiency for the chip, the reflection cup collects light emitted by the chip to play a role in primary collimation, and the Fresnel lens carries out secondary collimation on the collected light, so that the collimation effect and the luminous efficiency are effectively improved.

Description

Technical Field

[0001] This invention relates to the fields of Micro-LED display technology and optical precision manufacturing, and particularly to a Micro-LED lighting device having a combination of a reflector and a lens. Background Technology

[0002] With the rapid development of LED lighting technology, LED lamps have been widely used in the lighting field due to their advantages such as environmental friendliness, energy saving, high luminous efficacy, and long lifespan. However, the light distribution of LED directional lighting, spotlights, and flashlights on the market still mainly relies on a single reflector or focusing lens. This design has some limitations, especially when using lamps with a single COB light source board. Because the light-emitting surface of the COB light source board is relatively large, it is difficult to achieve uniform light distribution at small angles. In addition, traditional reflector or lens designs also have some problems in optical performance, such as strong stray light, uneven light spot, poor focusing effect, and large color difference, resulting in low luminous efficiency of the light source.

[0003] Against this backdrop, the emergence of Micro-LED technology offers a new approach to solving the aforementioned problems. As a novel solid-state light source, Micro-LED possesses advantages such as self-emission, fast response speed, low energy consumption, and long lifespan. However, effectively focusing and collimating the light from Micro-LEDs to improve their luminous efficiency remains a pressing technical challenge. Summary of the Invention

[0004] The purpose of this invention is to provide a Micro-LED lighting device with a reflector cup and lens combination and its manufacturing method. The light beam emitted by the Micro-LED first passes through the reflector cup with a reflective layer to concentrate the light, then passes through the Fresnel lens for secondary collimation, and finally passes through the transparent glass substrate for collimation and output. This can achieve effective concentration and collimation of the Micro-LED light, thereby improving the overall light efficiency.

[0005] To achieve the above objectives, the present invention provides a Micro-LED lighting device having a reflector and lens combination, comprising: Transparent substrate; A Fresnel lens array is disposed on the transparent substrate, comprising a plurality of Fresnel lenses arranged in an array, wherein the annular surface of the Fresnel lenses is close to the transparent substrate, and the annular surface of the Fresnel lenses is filled with a first photoresist layer; A reflector array, disposed on the Fresnel lens array, includes a plurality of reflectors arranged in an array, each reflector corresponding to a Fresnel lens and coaxially disposed, each reflector having a first opening at the end away from the Fresnel lens array and a second opening at the end closer to the Fresnel lens array, and a reflective layer provided on the inner surface of the reflector. Micro-LED chips are disposed on the reflector array, including a plurality of Micro-LEDs arranged in an array, wherein each Micro-LED and the reflector are disposed in a one-to-one correspondence and the light-emitting surface of the Micro-LED is disposed at the first opening; The diameter of the first opening of the reflector cup ranges from 5μm to 15μm, and the radius of the Fresnel lens ranges from 10μm to 25μm. The parabolic parameters of the reflector cup satisfy the following: the ratio of focal length f to the size of the Micro-LED light-emitting surface is in the range of 5-20.

[0006] Optionally, the ratio of the diameter of the first opening of the reflector cup to the size of the Micro-LED light-emitting surface is 1.0-1.5:1.

[0007] Optionally, the Micro-LED light-emitting surface is circular or square, and the size of the Micro-LED light-emitting surface is the diameter of the circle or the width of the square.

[0008] Optionally, the surface shape of the reflector satisfies the equation: z=(x²+y²) / 4f, where f is the focal length.

[0009] Optionally, the radius of the second opening of the reflector cup is less than or equal to the radius of the Fresnel lens.

[0010] Optionally, the annular band width d of the Fresnel lens satisfies: d≤λ / (2NA), where λ is the center wavelength of the Micro-LED and NA is the numerical aperture of the lens.

[0011] Optionally, the Fresnel lens has a refractive index of 1.3-1.6; and / or The ratio of the refractive index of the transparent substrate to the refractive index of the Fresnel lens is 0.9-1.1:1.

[0012] The present invention also provides a method for fabricating a Micro-LED lighting device having a reflector cup and a lens combination, the method comprising: S1. Fabrication of a Fresnel lens array master using photolithography; S2. A Fresnel lens array is transferred to a transparent substrate using nanoimprint technology; S3. Coat the first photoresist layer onto the Fresnel lens array; S4. Fabricate a master template for the reflective cup array using photolithography; S5. The reflective cup array is transferred to the side of the Fresnel lens array away from the transparent substrate using nanoimprint technology; S6. Prepare the reflective layer using vapor deposition or electroplating techniques; S7. Coat a second photoresist layer onto the reflective cup array with a reflective layer; S8. Remove part of the second photoresist layer to obtain the first opening of the reflector cup; S9. Integrate the Fresnel lens array and reflector array structure onto the Micro-LED chip to obtain a Micro-LED lighting device with a reflector and lens combination.

[0013] Optionally, the method for preparing the reflector array master includes: A continuous parabolic surface is formed on photoresist using grayscale lithography. Parabolic shapes are transferred to quartz substrates using nanoimprint technology.

[0014] Optionally, the method for fabricating the Fresnel lens array master includes: The ring structure was fabricated using laser grayscale direct-write lithography. A stepped profile is formed by grayscale exposure and development.

[0015] According to the present invention, (1) a combination structure of reflector and Fresnel lens is used to provide collimation and high efficiency for Micro-LED. The reflector gathers the light emitted by Micro-LED and plays a preliminary collimation role. The Fresnel lens performs secondary collimation on the gathered light, thus solving the problems of poor collimation effect and low luminous efficiency caused by single-layer lens array and other means. (2) The master is prepared by photolithography to ensure that the reflector cup has a good high-order aspherical surface shape at the micro-nano scale, which solves the problems of low precision of components at the micro-nano scale, no allowable error and high manufacturing cost. (3) The double-layer aspherical microlens array structure has a simple structure and is easy to prepare, which effectively improves the light output collimation of Micro-LED.

[0016] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Attached Figure Description

[0017] Figure 1 A schematic diagram of the structure of a Micro-LED lighting device having a reflector and lens combination, provided as an exemplary embodiment of the present invention; Figure 2 A schematic diagram of an imprinted Fresnel lens array provided as an exemplary embodiment of the present invention; Figure 3 A schematic diagram of coating a low-refractive-index adhesive onto a Fresnel lens array, provided as an exemplary embodiment of the present invention; Figure 4 A schematic diagram of a structure for aligning a transfer reflector array on a Fresnel lens array, provided as an exemplary embodiment of the present invention; Figure 5 A schematic diagram of a reflective layer coated on a reflective cup, provided as an exemplary embodiment of the present invention; Figure 6 A schematic diagram illustrating a method of photoresist encapsulating a reflective cup structure as provided in an exemplary embodiment of the present invention; Figure 7 A schematic diagram of the reflector cup cutting method provided as an exemplary embodiment of the present invention; Figure 8 A top-view schematic diagram of the entire structure after alignment, provided for an exemplary embodiment of the present invention.

[0018] Among them, transparent substrate-1; Fresnel lens array-2; Fresnel lens-21; reflector array-3; reflector-31; first opening-32; second opening-33; Micro-LED chip-4; reflective layer-5; second photoresist layer-6; first photoresist layer-7. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] Micro-LED chips feature a high-density integrated LED array with a pitch on the order of micrometers. Each Micro-LED in the array acts as a light-emitting surface, which can be independently addressed and lit to emit a pixel beam. The size of the light-emitting surface is typically 1-100 micrometers, and the spacing between adjacent light-emitting surfaces is extremely small, typically 1-200 micrometers. Furthermore, the beams emitted by the light-emitting surfaces usually have a certain divergence angle, resulting in stray light effects within the Micro-LED array. When applying Micro-LED chips to products such as directional lighting, spotlights, and flashlights, without the control of the emitted light, it is difficult to achieve the desired directional lighting effect.

[0022] When collimation of light emitted from Micro-LED chips is required, most conventional methods employ microlens arrays to refract and collimate the light at the critical surface. This method carries certain risks, as the collimation effect is significantly affected by lens fabrication precision and alignment errors with the chip. Furthermore, lens manipulation suffers from insufficient light-gathering ability, easily leading to low light efficiency. Light extraction efficiency and light utilization remain critical challenges for Micro-LED chips. Other phase manipulation methods, such as metasurface collimation, suffer from high processing costs, significantly impacting mass production.

[0023] Please see Figure 1 An exemplary embodiment of the present invention provides a Micro-LED lighting device having a reflector and lens combination, comprising a transparent substrate 1, a Fresnel lens array 2 disposed on the transparent substrate 1, a reflector array 3 disposed on the Fresnel lens array 2, and a Micro-LED chip 4 disposed on the reflector array 3.

[0024] The Micro-LED chip 4 comprises several Micro-LEDs arranged in an array. The light-emitting surface of the Micro-LED can be circular or square, and the size of the light-emitting surface ranges from 1 to 100 micrometers. When the light-emitting surface of the Micro-LED is circular, its size is the diameter of the circle; when the light-emitting surface of the Micro-LED is square, its size is the width of the square. The shape of the light-emitting surface is not specifically limited here; other shapes, such as hexagons, are also possible, but are not listed here.

[0025] Please see Figure 1 and Figure 7A reflector array 3 is disposed between the Micro-LED chip 4 and the Fresnel lens array 2. The reflector array 3 includes several reflectors 31 arranged in an array. Each reflector 31 has a first opening 32 at its end furthest from the Fresnel lens array 2 and a second opening 33 at its end closest to the Fresnel lens array 2. Each Micro-LED and reflector 31 is arranged in a one-to-one correspondence, with the light-emitting surface of the Micro-LED positioned at the first opening 32; that is, each light-emitting surface of a Micro-LED corresponds to a reflector 31. Optionally, the light-emitting surface of the Micro-LED and the center of the reflector 31 are aligned. Light emitted from each Micro-LED light-emitting surface enters the reflector 31 through the first opening 32 for focusing and exits through the second opening 33. The diameter of the first opening 32 of the reflector 31 must be greater than or equal to the size of the Micro-LED light-emitting surface, allowing the entire Micro-LED to enter the reflector 31. To reduce light loss, the first opening 32 covers the light-emitting surface of the Micro-LED. The ratio of the diameter of the first opening 32 of the reflector cup 31 to the size of the Micro-LED light-emitting surface is 1.0-1.5:1 to maximize the beam collection capability. The first opening 32 of the reflector cup 31 should not be too large, because Micro-LEDs have an array structure with periodically arranged light-emitting surfaces. An excessively large first opening 32 would cause crosstalk with the reflectors 31 corresponding to adjacent light-emitting surfaces, reducing the beam collection capability.

[0026] The inner surface of the reflector cup 31 is provided with a reflective layer 5, which is used to reflect light that shines on the inner wall of the reflector cup 31. In this embodiment, both the first opening 32 and the second opening 33 are circular, and the diameter of the first opening 32 is smaller than the diameter of the second opening 33, thereby ensuring that the light directly shines on the inner wall of the reflector cup 31 and, after multiple reflections, exits from the larger second opening 33 to form a directional beam, reducing light loss and making the beam more concentrated. The reflective layer 5 can be made of materials such as aluminum or chromium that can reflect the light emitted by the Micro-LED.

[0027] The diameter of the first opening 32 ranges from 5μm to 15μm, and the diameter of the second opening 33 ranges from 10μm to 25μm.

[0028] The parabolic parameters of the reflector 31 satisfy the following: the ratio of focal length f to the size of the Micro-LED emitting surface is in the range of 5-20. The reflector will converge the light emitted by the Micro-LED to a certain extent, but will not completely collimate it. When the divergence angle is converged, the Fresnel lens will perform the remaining collimation. When the ratio of focal length f to the size of the Micro-LED emitting surface is less than 5, the light emitted by the Micro-LED will be over-collimated when collimated by the reflector, which will have the opposite effect, and the light originally reflected to the upper wall will be reflected to the lower wall. When the ratio of focal length f to the size of the Micro-LED emitting surface is greater than 20, the reflector cannot converge the light emitted by the Micro-LED, and the effect after collimation by the Fresnel lens is deteriorated.

[0029] The surface shape of the reflector cup 31 satisfies the equation: z = (x² + y²) / 4f, where f is the focal length. The position of the Micro-LED can be flexibly set. The reflector cup 31 provides initial collimation of the Micro-LED, followed by secondary collimation with the Fresnel lens 21. Placing the Micro-LED at the focal point of the parabolic reflector cup efficiently reflects its divergent light into a quasi-parallel beam, significantly improving the directionality and light energy utilization of the light source. Please see Figure 1 , Figure 6 and Figure 7 It should be noted that the outer periphery of the reflector cup 31 is filled with a second photoresist layer 6. The second photoresist layer 6 can be prepared using photoresist of any refractive index and has no effect on the collimation effect of light.

[0030] Please see Figures 1 to 3 The Fresnel lens array 2 includes several Fresnel lenses 21 arranged in an array. Reflector cups 31 correspond one-to-one with the Fresnel lenses 21 and are coaxially arranged. The number of reflector cups 31, Fresnel lenses 21, and Micro-LED light-emitting surfaces is the same. Each Micro-LED light-emitting surface is provided with one reflector cup 31 and one Fresnel lens 21. The light emitted from the Micro-LED light-emitting surface is reflected and focused by the reflector cups 31, achieving initial collimation. The initially collimated light then enters the Fresnel lenses 21 for secondary collimation.

[0031] The annular band width d of Fresnel lens 21 satisfies: d≤λ / (2NA), where λ is the center wavelength of Micro-LED and NA is the numerical aperture of the lens.

[0032] The Fresnel lens 21 has a refractive index of 1.3-1.6. The radius of the Fresnel lens 21 ranges from 10μm to 25μm. The annular zone of the Fresnel lens 21 is filled with a first photoresist layer 7. The refractive index of the first photoresist layer 7 is lower than that of the Fresnel lens 21, and its refractive index ranges from 1.3-1.6. By utilizing the different refractive indices of the reflector cup 31 and the Fresnel lens 21, the converged light rays are refracted at the interface, improving the collimation effect.

[0033] The reflector cup 31 and the corresponding Fresnel lens 21 are coaxially aligned, and the radius of the second opening 33 of the reflector cup 31 is less than or equal to the radius of the Fresnel lens 21, thereby ensuring that all the light gathered by the reflector cup 31 can enter the Fresnel lens 21 for collimation.

[0034] A Fresnel lens array 2 is disposed on a transparent substrate 1, with the annular surface of the Fresnel lens 21 close to the transparent substrate 1. The transparent substrate 1 is a transparent flat plate made of transparent material such as a glass substrate. The refractive index of the transparent substrate 1 is equal to or close to the refractive index of the Fresnel lens 21, thereby ensuring that the light emitted by the Micro-LED remains directional after being collimated by the light-emitting cup and the Fresnel lens 21 and then passing through the transparent substrate 1. Optionally, the ratio of the refractive index of the transparent substrate 1 to the refractive index of the Fresnel lens 21 is 0.9-1.1:1. When a glass substrate is used as the transparent substrate 1, the refractive index of the transparent substrate 1 is 1.52.

[0035] The combination structure of reflector 31 and Fresnel lens 21 provides collimation and high efficiency for Micro-LED. The reflector 31 focuses the light emitted by Micro-LED, playing a preliminary collimation role, while the Fresnel lens 21 performs secondary collimation on the focused light, solving the problems of poor collimation effect and low luminous efficiency caused by single-layer lens arrays and other methods.

[0036] The present invention also provides a method for fabricating a Micro-LED lighting device having a reflector cup and a lens combination, the method comprising: S1. Fabrication of a Fresnel lens array master using photolithography; S2. A Fresnel lens array is transferred to a transparent substrate using nanoimprint technology; S3. Coat the first photoresist layer onto the Fresnel lens array; S4. Fabricate a master template for the reflective cup array using photolithography; S5. The reflective cup array is transferred to the side of the Fresnel lens array away from the transparent substrate using nanoimprint technology; S6. Prepare the reflective layer using vapor deposition or electroplating techniques; S7. Coat a second photoresist layer onto the reflective cup array with a reflective layer; S8. Remove part of the second photoresist layer to obtain the first opening of the reflector cup; S9. Integrate the Fresnel lens array and reflector array structure onto the Micro-LED chip to obtain a Micro-LED lighting device with a reflector and lens combination.

[0037] It should be noted that the order of the above steps is not limited. The above is just an example. Optionally, steps S1 and S2 can be completed before proceeding to the other steps.

[0038] The master copy of the Fresnel lens array can be prepared using laser direct-write lithography, laser grayscale direct-write lithography, electron beam lithography, and mask lithography. Similarly, the master copy of the reflector cup array can also be prepared using laser direct-write lithography, laser grayscale direct-write lithography, electron beam lithography, and mask lithography.

[0039] In this embodiment, please refer to Figure 2 When transferring a Fresnel lens array onto a transparent substrate using nanoimprint lithography, the refractive index of the UV adhesive used is equal to or close to that of the transparent substrate, with the selected UV adhesive having a refractive index range of 1.3-1.6. After the transfer is completed, the Fresnel lens array and the master substrate are separated, resulting in a uniform Fresnel lens array on the transparent substrate. Please refer to [link to relevant documentation]. Figure 3 A layer of photoresist is coated onto the Fresnel lens array and cured to form a uniform first photoresist layer. See also... Figure 4 and Figure 5 Then, a parabolic reflector array is transferred onto the Fresnel lens array using nanoimprint lithography. After curing and demolding, a reflective layer is deposited by vapor deposition or electroplating. Please see [link to relevant documentation]. Figure 6 A layer of photoresist is coated or imprinted onto the reflective layer for encapsulation, forming a second photoresist layer. Optionally, after the reflective layer is prepared, photoresist is coated and exposed for curing to form a smooth second photoresist layer. Please refer to [link to relevant documentation]. Figure 7 A suitable thickness of the second photoresist layer is removed using laser or imprinting demolding methods, controlling the diameter of the reflector opening at the cut-off point to be 1-1.5 times the size of the Micro-LED emitting surface. Please refer to [link / reference]. Figure 1 By inverted bonding, the reflector cup and Fresnel lens combination structure are integrated onto the Micro-LED chip, thus completing the fabrication of a high-efficiency, high-collimation Micro-LED lighting device with a reflector cup and lens combination.

[0040] It should be noted that, in order to ensure the coaxial alignment of the reflector and the Fresnel lens, the fabrication method also includes: Please refer to [link to relevant documentation]. Figure 8A target is set on the Fresnel lens array, and the imprinting position of the reflector array is determined based on the target. This method is simple to operate and has high coaxial alignment accuracy, ensuring the collimation effect of the light emitted by the Micro-LED. Specifically, a first target, which can be concave or convex, is set on the Fresnel lens array master plate. The target is transferred to the Fresnel lens array using nanoimprinting technology. A second target, which can be convex or concave, is set on the reflector array master plate; when the second target is aligned with the target on the Fresnel lens array, the Fresnel lens is aligned with the parabolic convex structure on the reflector array master plate.

[0041] In one embodiment, the method for fabricating a Fresnel lens array master includes: The ring structure was fabricated using laser grayscale direct-write lithography. A stepped profile is formed by grayscale exposure and development.

[0042] A master template for a Fresnel lens array is fabricated using laser grayscale direct-write lithography. The master template features Fresnel lens structures, including lens surfaces and annular band structures. The master template is made of photoresist. A template for the Fresnel lens array is then transferred from the master template using nanoimprint lithography, creating a matching array of Fresnel annular recesses on the imprinted surface. Finally, a master template for the Fresnel lens array is created by transferring the template using nanoimprint lithography, resulting in an array of Fresnel annular protrusions on the master template that correspond to the Fresnel lenses.

[0043] The methods for preparing the reflector array master include: A continuous parabolic surface is formed on photoresist using grayscale lithography. Parabolic shapes are transferred to quartz substrates using nanoimprint technology.

[0044] A master template for the reflector array is obtained using grayscale photolithography. This master template features a raised array of parabolic reflector cups and is made of photoresist. A nanoimprinting technique is then used to transfer the master template to obtain a reflector array template, creating a recessed array of reflector cups on the imprinted surface that matches the raised array of the reflector cups.

[0045] The master plate is prepared by photolithography to ensure that the reflector cup has a good high-order aspherical surface shape at the micro-nano scale, which solves the problems of low precision of components at the micro-nano scale, no allowable error, and high manufacturing cost. The double-layer aspherical microlens array structure has a simple structure and simple preparation method, which effectively improves the light output collimation of Micro-LED.

[0046] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0047] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A Micro-LED lighting device comprising a reflector cup and a lens combination, characterized in that, include: Transparent substrate; A Fresnel lens array is disposed on the transparent substrate, comprising a plurality of Fresnel lenses arranged in an array, wherein the annular surface of the Fresnel lenses is close to the transparent substrate, and the annular surface of the Fresnel lenses is filled with a first photoresist layer; A reflector array, disposed on the Fresnel lens array, includes a plurality of reflectors arranged in an array, each reflector corresponding to a Fresnel lens and coaxially disposed, each reflector having a first opening at the end away from the Fresnel lens array and a second opening at the end closer to the Fresnel lens array, and a reflective layer provided on the inner surface of the reflector. Micro-LED chips are disposed on the reflector array, including a plurality of Micro-LEDs arranged in an array, wherein each Micro-LED and the reflector are disposed in a one-to-one correspondence and the light-emitting surface of the Micro-LED is disposed at the first opening; The diameter of the first opening of the reflector cup ranges from 5μm to 15μm, and the radius of the Fresnel lens ranges from 10μm to 25μm. The parabolic parameters of the reflector cup satisfy the following: the ratio of focal length f to the size of the Micro-LED light-emitting surface is in the range of 5-20.

2. The Micro-LED lighting device with a reflector and lens combination according to claim 1, characterized in that, The ratio of the diameter of the first opening of the reflector cup to the size of the Micro-LED light-emitting surface is 1.0-1.5:

1.

3. The Micro-LED lighting device with a reflector and lens combination according to claim 1 or 2, characterized in that, The Micro-LED light-emitting surface is circular or square, and the size of the Micro-LED light-emitting surface is the diameter of the circle or the width of the square.

4. The Micro-LED lighting device with a reflector and lens combination according to claim 1, characterized in that, The surface shape of the reflector satisfies the equation: z=(x²+y²) / 4f, where f is the focal length.

5. The Micro-LED lighting device with a reflector and lens combination according to claim 1, characterized in that, The radius of the second opening of the reflector cup is less than or equal to the radius of the Fresnel lens.

6. The Micro-LED lighting device with a reflector and lens combination according to claim 1, characterized in that, The band width d of the Fresnel lens satisfies: d≤λ / (2NA), where λ is the center wavelength of the Micro-LED and NA is the numerical aperture of the lens.

7. The Micro-LED lighting device with a reflector and lens combination according to claim 1, characterized in that, The Fresnel lens has a refractive index of 1.3-1.6; and / or The ratio of the refractive index of the transparent substrate to the refractive index of the Fresnel lens is 0.9-1.1:

1.

8. A method for manufacturing a Micro-LED lighting device comprising a reflector cup and a lens combination, characterized in that, The preparation method includes: S1. Fabrication of a Fresnel lens array master using photolithography; S2. A Fresnel lens array is transferred to a transparent substrate using nanoimprint technology; S3. Coat the first photoresist layer onto the Fresnel lens array; S4. Fabricate a master template for the reflective cup array using photolithography; S5. The reflective cup array is transferred to the side of the Fresnel lens array away from the transparent substrate using nanoimprint technology; S6. Prepare the reflective layer using vapor deposition or electroplating techniques; S7. Coat a second photoresist layer onto the reflective cup array with a reflective layer; S8. Remove part of the second photoresist layer to obtain the first opening of the reflector cup; S9. Integrate the Fresnel lens array and reflector array structure onto the Micro-LED chip to obtain a Micro-LED lighting device with a reflector and lens combination.

9. The method for manufacturing a Micro-LED lighting device with a reflector cup and lens combination according to claim 8, characterized in that, The method for preparing the reflector array master includes: A continuous parabolic surface is formed on photoresist using grayscale lithography. Parabolic shapes are transferred to quartz substrates using nanoimprint technology.

10. The method for manufacturing a Micro-LED lighting device with a reflector cup and lens combination according to claim 8, characterized in that, The method for preparing the Fresnel lens array master includes: The ring structure was fabricated using laser grayscale direct-write lithography. A stepped profile is formed by grayscale exposure and development.

Images