Optical film and its manufacturing process, LED optical module

Abstract

The present invention relates to the field of LED technology, and discloses an optical film and its manufacturing process, and an LED optical module. The optical film has a light incident surface and a light emitting surface arranged opposite to each other along its thickness direction, and includes: a substrate and a plurality of optical lenses; the substrate is provided with matrix-arranged stamped holes, and the optical lenses are arranged in the stamped holes; each of the optical lenses includes a columnar structure and a hemispherical top cap connected to the top of the columnar structure, which is used to refract the divergent light incident from the light incident surface so that the divergent light is focused and emitted. Compared with the traditional microlens structure, the embodiment of the present invention not only has a better light focusing effect, improves the light output rate, increases the light output intensity, and reduces crosstalk, but also has a simple implementation process and low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of LEDs, and in particular to an optical film and a manufacturing process thereof, and an LED optical module. Background Art

[0002] With the development of technology, LED chips are becoming more and more miniaturized and integrated, and Micro_LED was born, attracting widespread attention.

[0003] When micro-LEDs emit light, they typically diverge, resulting in poor directivity. When applied to displays, particularly VR devices, this light divergence can easily cause image blur, also known as optical crosstalk, affecting the display quality. Furthermore, excessive light divergence within the transmission area can also reduce effective optical power.

[0004] To address this, microlenses are currently commonly used to focus light more effectively and reduce crosstalk. However, due to their structural characteristics of only comprising a single layer of lenses, the light focusing effect is poor. Furthermore, due to the extremely small size of Micro-LEDs, the implementation of microlens solutions remains challenging. Summary of the Invention

[0005] The purpose of the present invention is to provide an optical film and its manufacturing process, and an LED optical module, so as to overcome the defects of the prior art such as poor light focusing effect and high implementation difficulty.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] An optical film having a light incident surface and a light emitting surface disposed opposite to each other along its thickness direction, comprising: a substrate and a plurality of optical lenses; the substrate is provided with a plurality of embossed holes arranged in a matrix, the optical lenses being disposed in the embossed holes;

[0008] Each of the optical lenses includes a column structure and a hemispherical top cap connected to the top of the column structure.

[0009] Optionally, the hemispherical top cap protrudes from the corresponding embossed hole and is used to refract the divergent light incident from the light incident surface so that the divergent light is focused and emitted.

[0010] Optionally, the column structure is formed by stacking at least one layer of first membrane, and the refractive index of the first membrane is smaller than the refractive index of the hemispherical top cap.

[0011] Optionally, the light incident surface of the substrate is provided with a film stack, and the film stack is stacked with at least one second film layer. On the at least one second film layer at the bottom layer on the light incident side, alignment grooves for embedding LEDs are respectively provided at corresponding positions of each optical lens.

[0012] Optionally, the film stack includes multiple layers of second films, and the refractive index of each layer of the second film gradually increases along the direction from the light incident surface to the light emitting surface.

[0013] Optionally, the inner sidewall of the embossed hole is coated with a light scattering material layer or a reflective material layer, and the second membrane is a flexible material added with a light absorbing material.

[0014] Optionally, the surface of the hemispherical top cap is coated with a protective film, and the column structure includes multiple layers of first films, and the refractive index of each layer of the first films gradually increases along the direction from the light incident surface to the light emitting surface.

[0015] Optionally, light absorbing material is added to the substrate.

[0016] An LED optical module comprises: a driving circuit, a plurality of LEDs bonded to the driving circuit, and the optical film described in any one of the above items;

[0017] The plurality of LEDs are arranged on the light incident side of the optical film, and each of the LEDs corresponds to each of the optical lenses one by one.

[0018] Optionally, the light incident surface of the substrate is further stacked with at least one second film, and at least one second film located at the bottom layer on the light incident side is provided with a plurality of alignment grooves for embedding LEDs;

[0019] Each of the LEDs is fixed in the alignment groove.

[0020] Optionally, at least one layer of the second membrane is a conductive layer, and the LED is provided with a positive electrode and a negative electrode, the negative electrode is connected to the conductive layer, and the positive electrodes are respectively connected to the driving circuit.

[0021] A process for manufacturing an optical film as described in any one of the above items, the process comprising:

[0022] Providing a substrate and a first nanoimprint template, wherein the first nanoimprint template includes a columnar protrusion matching the column structure of the optical lens;

[0023] First, a first material is coated on the surface of the substrate to form the base sheet;

[0024] Then, using the light-emitting surface of the substrate as an imprinting surface, the substrate is imprinted using the first nanoimprint template to form a plurality of imprinting holes on the substrate;

[0025] Then, a second material is dripped, sprayed or coated into each of the embossed holes to form a columnar structure of the optical lens;

[0026] Providing a second nanoimprint template, wherein the second nanoimprint template includes a hemispherical concave portion matching the hemispherical top cap of the optical lens;

[0027] After the hemispherical concave portion of the second nanoimprint template is filled with the second material or the third material, the second nanoimprint template is used to imprint the substrate to form a hemispherical top cap on the top of the columnar structure in the imprinted hole.

[0028] Optionally, light absorbing material is added to the first material.

[0029] Optionally, the manufacturing process further includes:

[0030] providing a plurality of second diaphragms;

[0031] Transferring the plurality of LEDs to a positioning film, wherein the positioning film is at least one second film connected to the LEDs;

[0032] encapsulating the positioning membrane to form a membrane stack;

[0033] The film stack is arranged on the light incident surface of the substrate.

[0034] Optionally, the manufacturing process further includes:

[0035] Performing optical grinding and polishing on the light-emitting surface of the optical lens;

[0036] The light incident surface of the substrate of the optical film is thinned to remove part of the substrate material so as to expose the columnar structure of the optical lens.

[0037] Optionally, the step of transferring the plurality of LEDs into the positioning film includes:

[0038] Providing a third nanoimprint template, and applying the third nanoimprint template to imprint the positioning film to form a plurality of alignment grooves for embedding LEDs;

[0039] An LED is installed in each of the alignment grooves.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] On the one hand, in the embodiments of the present invention, optical lenses are formed at the positions of the various embossed holes of the substrate, and each optical lens is composed of a cylindrical structure at the bottom and a hemispherical top cap at the top, forming an upper and lower layer of lenses. In use, a portion of the divergent light emitted by the bottom LED is directly emitted after being refracted by the cylindrical structure and the hemispherical top cap, while a portion is totally reflected at the edge of the cylindrical structure and then emitted after being refracted by the cylindrical structure and the hemispherical top cap. The emitted light can be focused near the axis area. Therefore, compared with the traditional microlens structure, it has a better light focusing effect, improves the light output rate, and increases the light output intensity.

[0042] On the other hand, by applying the embodiment of the present invention, the entire second optical film can be directly bonded to multiple LEDs, and then the second film can be bonded to the upper optical lens, which can effectively get rid of the limitation of the small size of a single LED. Since the second film can be made of flexible material, the second film also has the function of protecting the lens and LED. Compared with the traditional microlens structure, not only is the implementation process simple, but the cost is also low. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0044] Figure 1 A top view of an optical film provided by an embodiment of the present invention;

[0045] Figure 2 A cross-sectional view of a first optical film provided by an embodiment of the present invention;

[0046] Figure 3 A cross-sectional view of a second optical film provided by an embodiment of the present invention;

[0047] Figure 4 for Figure 3 Schematic diagram of the light path of a single LED in the optical film shown;

[0048] Figure 5 A cross-sectional view of a third optical film provided by an embodiment of the present invention;

[0049] Figure 6 A cross-sectional view of an optical lens provided by an embodiment of the present invention;

[0050] Figure 7 A flowchart of a manufacturing process for an optical film according to an embodiment of the present invention;

[0051] Figure 8 (1)- Figure 8 (4) is a schematic diagram of the manufacturing process of the optical film provided in an embodiment of the present invention.

[0052] Description of the accompanying drawings:

[0053] Substrate 1, imprint hole 11, optical lens 2, column structure 21, hemispherical top cap 22, membrane stack 3, LED 4, first nanoimprint template 5, nozzle 6, second nanoimprint template 7, third nanoimprint template 8. DETAILED DESCRIPTION

[0054] In order to make the purpose, features, and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0055] Example 1

[0056] See also Figures 1 to 3 The embodiment of the present invention provides an optical film having a light incident surface and a light emitting surface disposed opposite to each other along its thickness direction, which is used to realize the function of converging divergent light, and mainly includes: a substrate 1 and a plurality of optical lenses 2;

[0057] The substrate 1 is provided with embossed holes 11 arranged in a matrix, and each embossed hole 11 is provided with an optical lens 2;

[0058] Each optical lens 2 is used to refract the divergent light incident from the light incident surface so that the divergent light is focused and emitted, and includes a columnar structure 21 and a hemispherical top cap 22 connected to the top of the columnar structure 21. The columnar structure 21 is completely accommodated in the corresponding embossed hole 11, and the hemispherical top cap 22 can partially protrude from the corresponding embossed hole 11 or be embedded in the embossed hole 11.

[0059] like Figure 3 As shown, the light incident surface of the substrate 1 may also be provided with a film stack 3 having a refractive effect to enhance the light focusing effect. The film stack 3 is composed of at least one second film layer.

[0060] On the one hand, in the embodiment of the present invention, the optical lens 2 is formed at each embossed hole 11 of the substrate 1, and each optical lens 2 is composed of a columnar structure 21 at the bottom and a hemispherical cap 22 at the top, forming a structure having the following characteristics: Figure 4The upper and lower layers of lenses in the optical path shown; when in use, part of the divergent light emitted by the bottom LED 4 is directly emitted after being converged and refracted by the cylindrical structure and the hemispherical top cap 22, and part of the light is emitted after being totally reflected at the edge of the cylindrical structure and then being converged and refracted by the cylindrical structure and the hemispherical top cap 22. The emitted light can be gathered near the axis area. Therefore, compared with the traditional microlens structure, it has a better light gathering effect, improves the light output rate, and increases the light output intensity.

[0061] On the other hand, in the optical film provided by the embodiment of the present invention, multiple optical lenses 2, substrate 1 and film stack 3 are an integrated structure. When used, the entire optical film 3 can be directly bonded to multiple LEDs 4 and then used, which can effectively get rid of the limitation of the small size of a single LED 4. Compared with the traditional microlens structure, not only is the implementation process simple, but also the cost is low.

[0062] It should be noted that the embodiments of the present invention do not impose specific restrictions on the material types of the diaphragm stack 3 and the optical lens 2, as long as the general principle is that the refractive index of the optical lens 2 is greater than the refractive index of the diaphragm stack 3. Specifically, the diaphragm stack 3 and the optical lens 2 can be selected from the following list of suitable refractive materials. For example, the diaphragm stack 3 can be made of PET with a refractive index of approximately 1.65, PC polycarbonate with a refractive index of approximately 1.5, or silicone with a lower refractive index. The optical lens 2 can be made of a material with a higher refractive index, such as PET with an added hydrogenated silicon material having a refractive index of approximately 3.2.

[0063] Material Refractive index PET material 1.65 PC polycarbonate 1.5 Fluorinated multifunctional (meth)acrylate 1.5 Silicon hydride 3.2 Silicon oxide 0.35 Phenyl silicone 1.54 Methyl silicone 1.41 Silicon nitride 2.0

[0064] In order to further enhance the light gathering effect of the optical film, such as Figure 3 As shown, the diaphragm stack 3 includes at least one layer of second diaphragms arranged in sequence along its thickness direction. When the second diaphragm includes multiple layers, the refractive index of each layer of the second diaphragms in the diaphragm stack 3 gradually increases from the light incident surface to the light exiting surface. In this way, the diaphragm stack 3 is equivalent to adopting a step-by-step convergent refraction method. Compared with the one-step convergent refraction method, it reduces the sudden change in the refractive index of different film layers, which causes the light to be totally reflected at the contact surface, and forms diffuse reflection between multiple film layers, thereby increasing the viewing angle of the image. Therefore, a better light focusing effect can be obtained, crosstalk problems can be reduced, and the viewing angle can be expanded. In practical applications, the thickness and material type of each layer of the second diaphragm can be designed according to actual needs to obtain different refractive effects.

[0065] Preferably, on the film stack 3, alignment grooves for embedding the LEDs 4 are provided at corresponding positions of the optical lenses 2. There are several ways to implement the alignment grooves:

[0066] The first one, such as Figure 5As shown, the alignment groove is opened on the second film at the bottom layer on the light incident side in the film stack 3, but does not pass through the second film;

[0067] The second type is that the alignment groove runs through the second film located at the bottom layer on the light incident side;

[0068] The third type is that the alignment groove continuously penetrates two or more layers of the second diaphragm.

[0069] For the convenience of description, all the second diaphragms connected to the alignment grooves may be collectively referred to as positioning diaphragms.

[0070] Furthermore, the alignment groove can be formed by firstly manufacturing a plurality of through holes on a plurality of second films using an independent process, and then attaching the second films to the light incident surface of the substrate to form the alignment groove.

[0071] Thus, during assembly, the LED 4 can be directly embedded in the alignment groove, which can achieve simple, rapid and accurate alignment of the LED 4 and the optical film. Before assembly, a layer of adhesive can be applied to the sidewalls of the alignment groove to achieve a fixed connection between the LED 4 and the film stack 3.

[0072] Similarly, if Figure 6 As shown, the columnar structure 21 of the optical lens 2 includes at least two layers of first films arranged sequentially along its height. The refractive index of each layer of first films gradually increases from the light incident surface to the light exit surface. This further enhances the light focusing effect due to the refraction of light from the optically less dense medium to the optically dense medium.

[0073] In order to further improve the light output rate, the inner side walls of each embossed hole 11 are also coated with a light scattering material layer or a reflective material layer. This material layer can diffusely reflect the divergent light emitted from the side wall of the columnar structure 21, so that it enters the optical lens 2 again and is emitted through the curved surface of the hemispherical top cap 22, thereby improving the light output rate and brightness, and increasing the viewing angle.

[0074] In addition, light-absorbing material is added to the substrate 1. Since the optical lenses 2 are located in the embossed holes 11, which are arranged in a matrix on the substrate 1, the light paths of any two adjacent optical lenses 2 can be isolated by the light-absorbing material distributed in the area between them, effectively preventing optical crosstalk between pixels.

[0075] Further, continue to refer to Figure 6 As shown, light-absorbing materials can also be added to the second membrane to prevent light from reflecting off the second membrane and causing crosstalk. The second membrane is made of a flexible material to protect the LED. The thickness of each layer of the second membrane is not limited and can be flexibly designed based on actual needs.

[0076] To prevent damage during use, the light-emitting side of the optical film and the surface of each hemispherical cap 22 are coated with a protective film. This design can effectively protect the optical lens 2 and LED from damage by external factors, improve the reliability of the optical film, and extend its service life.

[0077] Example 2

[0078] An embodiment of the present invention provides an LED optical module, comprising: a driving circuit, multiple LEDs 4 bonded to the driving circuit, and an optical film as in the first embodiment; the multiple LEDs 4 are arranged on the light incident side of the optical film, and each LED 4 corresponds to each optical lens 2 one by one.

[0079] In an optional embodiment, the LED 4 and the film laminate 3 are bonded by thermally conductive adhesive. Of course, in addition to the thermally conductive adhesive bonding method, any other conventional fixing method can also be used as long as it can ensure a stable connection between the LED 4 and the optical film.

[0080] The light incident surface of the substrate 1 is further stacked with a film stack 3 comprising at least one second film layer, wherein the second film layer located at the bottom layer on the light incident side is provided with a plurality of alignment grooves for embedding LEDs;

[0081] At least one layer of the second membrane is a conductive layer. The LED 4 is provided with a positive electrode and a negative electrode. The negative electrode is connected to the conductive layer, and the positive electrodes are respectively connected to the driving circuit.

[0082] Since the optical film described in the first embodiment has a good light-converging function, when applied to an LED optical module, it can effectively reduce the problem of image blur and crosstalk, and can also widen the viewing angle and improve image quality.

[0083] Example 3

[0084] In view of the optical film described in the first embodiment, the third embodiment of the present invention provides a process for manufacturing an optical film, such as Figure 7 and Figure 8 As shown, the steps include:

[0085] Step 101 : providing a substrate and a first nanoimprint template 5 , wherein a pressing surface of the first nanoimprint template 5 is provided with a columnar protrusion matching the column structure 21 of the optical lens 2 .

[0086] Step 102 : coating a first material on the surface of the substrate to form a base sheet 1 .

[0087] Light-absorbing material is added to the first material to isolate the light paths of any two adjacent optical lenses 2, thereby effectively preventing crosstalk.

[0088] Step 103 : Using the light-emitting surface of the substrate 1 as the imprinting surface, use the first nanoimprint template 5 to imprint the substrate 1 , so as to form a plurality of imprint holes 11 on the light-emitting surface of the substrate 1 .

[0089] After forming the embossed holes 11, a light-scattering material or a light-reflecting material can be further coated and cured within each embossed hole 11 to improve light extraction and brightness while also increasing the viewing angle. Specifically, the material can be powders such as ZnO and TiO2, which are composed of a large number of irregular nanoparticles and are relatively easy to manipulate in shape.

[0090] It should be noted that the stamped hole 11 can be either a through hole or a blind hole, and there is no specific limitation.

[0091] Step 104 : drip, spray or apply the second material into each of the embossing holes 11 and heat and cure it to form a columnar structure of multiple optical lenses 2 .

[0092] When the columnar structure 21 includes at least two layers of first films with different refractive indices, materials with different refractive indices can be sprayed sequentially into the stamped holes 11 during the manufacturing process.

[0093] Step 105 : providing a second nanoimprint template 7 , wherein the second nanoimprint template 7 comprises a hemispherical concave portion matching the hemispherical top cap 22 of the optical lens 2 .

[0094] Step 106: After filling the hemispherical concave portion of the second nanoimprint template 7 with the second material or the third material, the second nanoimprint template 7 is used to imprint the substrate 1 to form a hemispherical top cap 22 at the top of the columnar structure in the imprint hole 11, thereby completing the production of the substrate 1 and the optical lens 2.

[0095] After the optical lens 2 is formed, the light-emitting surface of the optical lens 2 may be further optically ground and polished.

[0096] In addition, when the embossed hole 11 is a blind hole, the light incident surface of the optical film may be thinned to remove part of the substrate material so that the light incident surface of the optical lens 2 is exposed.

[0097] It should be noted that the cylindrical portion and the hemispherical top cap 22 constituting the optical lens 2 are both made of materials with a high refractive index to achieve a good light focusing function; however, the two can be made of the same material or different materials, and the present invention does not impose any specific restrictions on this.

[0098] In general, the above-mentioned manufacturing process first uses nanoimprint technology to form an imprint hole 11 in the substrate 1, and then uses dripping, spraying or coating to form a columnar structure 21 of the optical lens 2 in the imprint hole 11, and then uses nanoimprint technology to form a hemispherical top cap 22 on the top of the columnar structure 21. Since the nanoimprint technology and dripping / spraying / coating technology have simple processes, low implementation difficulty and strong controllability, the optical film produced has excellent quality and low implementation cost.

[0099] In an optional embodiment, the above-mentioned manufacturing process may further include:

[0100] Step 107: provide a positioning film, which refers to the second film of the film stack 3 connected to the LED in the light incident direction; transfer multiple LEDs to the positioning film, encapsulate the positioning film to form the film stack 3, and then set the film stack 3 on the light incident surface of the substrate 1.

[0101] The packaging may include making an ITO circuit layer, coating a transparent protective layer, etc.

[0102] In the case where the membrane stack 3 includes multiple layers of second membranes, each layer of the second membrane can be manufactured sequentially according to the stacking order.

[0103] There are multiple transfer methods for transferring multiple LEDs into the positioning film. For example, a third nanoimprint template 8 can be provided, and the third nanoimprint template 8 is used to imprint the positioning film to form multiple alignment grooves on the positioning film for embedding LEDs 4, and the LEDs 4 are embedded in the alignment grooves.

[0104] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A process for manufacturing an optical film, characterized in that: The optical film has a light incident surface and a light exit surface disposed opposite to each other along its thickness direction, and specifically comprises: a substrate and a plurality of optical lenses; the substrate is provided with a plurality of embossed holes arranged in a matrix, and the optical lenses are disposed in the embossed holes; Each of the optical lenses includes a cylindrical structure and a hemispherical top cap connected to the top of the cylindrical structure; The manufacturing process of the optical film includes: Providing a substrate and a first nanoimprint template, wherein the first nanoimprint template includes a columnar protrusion matching the column structure of the optical lens; First, a first material is coated on the surface of the substrate to form the base sheet; Then, using the light-emitting surface of the substrate as an imprinting surface, the substrate is imprinted using the first nanoimprint template to form a plurality of imprinting holes on the substrate; Then, a second material is dripped, sprayed or coated into each of the embossed holes to form a columnar structure of the optical lens; Providing a second nanoimprint template, wherein the second nanoimprint template includes a hemispherical concave portion matching the hemispherical top cap of the optical lens; After the hemispherical concave portion of the second nanoimprint template is filled with the second material or the third material, the second nanoimprint template is used to imprint the substrate to form a hemispherical top cap on the top of the columnar structure in the imprinted hole.

2. The process for manufacturing an optical film according to claim 1, wherein: The hemispherical top cap protrudes from the corresponding embossed hole and is used for refracting the divergent light incident from the light incident surface so that the divergent light is focused and emitted.

3. The process for manufacturing an optical film according to claim 1, wherein: The column structure is formed by stacking at least one layer of first membrane, and the refractive index of the first membrane is smaller than the refractive index of the hemispherical top cap.

4. The process for manufacturing an optical film according to claim 1, wherein: The light incident surface of the substrate is provided with a film stack, and the film stack is stacked with at least one second film layer. On the at least one second film layer at the bottom layer on the light incident side, alignment grooves for embedding LEDs are respectively provided at corresponding positions of each optical lens.

5. The process for manufacturing an optical film according to claim 4, wherein: The film stack includes multiple layers of second films, and along the direction from the light incident surface to the light emitting surface, the refractive index of each layer of the second film gradually increases.

6. The process for manufacturing an optical film according to claim 4, wherein: The inner sidewall of the embossed hole is coated with a light scattering material layer or a reflective material layer, and the second membrane is made of a flexible material added with a light absorbing material.

7. The process for manufacturing an optical film according to claim 3, wherein: The surface of the hemispherical top cap is coated with a protective film; the column structure comprises multiple layers of first films, and the refractive index of each layer of the first films gradually increases along the direction from the light incident surface to the light emitting surface.

8. The process for manufacturing an optical film according to claim 1, wherein: Light absorbing material is added into the substrate.

9. The process for manufacturing an optical film according to claim 1, wherein: In the manufacturing process, light absorbing material is added into the first material.

10. The process for manufacturing an optical film according to claim 1, wherein: The manufacturing process also includes: providing a plurality of second diaphragms; Transferring the plurality of LEDs to a positioning film, wherein the positioning film is at least one second film connected to the LEDs; encapsulating the positioning membrane to form a membrane stack; The film stack is arranged on the light incident surface of the substrate.

11. The process for manufacturing an optical film according to claim 1, wherein: The manufacturing process also includes: Performing optical grinding and polishing on the light-emitting surface of the optical lens; The light incident surface of the substrate of the optical film is thinned to remove part of the substrate material so as to expose the columnar structure of the optical lens.

12. The process for manufacturing an optical film according to claim 10, wherein: The step of transferring the plurality of LEDs into the positioning film comprises: Providing a third nanoimprint template, and applying the third nanoimprint template to imprint the positioning film to form a plurality of alignment grooves for embedding LEDs; An LED is installed in each of the alignment grooves.

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