Diffusion film and diffusion film preparation method

Abstract

A diffusion film and a diffusion film preparation method, wherein the diffusion film has continuous or discontinuous optical microstructures on the light-out surface and / or the light-in surface, the optical microstructures have a stacked structure, the optical microstructures at least include a platform, the platform has at least one light-out end surface, and the platform has at least one continuous light-out circumferential surface, the included angle between the light-out end surface of the platform and the light-out circumferential surface of the platform is a right angle, the profile of the platform increases / decreases in turn along the direction perpendicular to the light-out surface of the diffusion film, forms a stepped structure, and the projection of the platform at a previous level is located within the profile of the platform at a next level. The diffusion film preparation method is used for preparing the above diffusion film. The diffusion film increases the light mixing effect between LED lamps, weakens the dark light band between the LED lamps, and finally improves the light uniformity of the diffusion film.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical film technology, in particular to a diffusion film and a diffusion film preparation method. BACKGROUND

[0002] With the large application of liquid crystal display, the backlight module as an important component of the liquid crystal display panel plays a very important role in improving the quality of the display and promoting the process of thinning the liquid crystal panel. According to the different positions of the light source in the backlight module, the backlight module can be divided into direct type and side type backlight. Unlike the light source of the side type arranged on the side of the light emitting surface, the light source of the direct type is directly distributed under the light emitting surface and does not need to pass through the light guide plate. However, since the LED light source has a specific light emitting area, the LED light intensity is not uniform in the specific viewing angle distribution, and it is difficult for the LED light source to form uniform emitted light on the target surface, that is, it is difficult to form a surface light source, so light mixing treatment is needed to weaken the dark area or light emitting dark band or visible LED light device phenomenon caused by the LED light source.

[0003] At present, the traditional direct type structure generally arranges two layers of diffusion films with light mixing function above the LED light source. The main function of the light diffusion film is to convert point light source and line light source into surface light source, and it has the characteristics of high light transmittance and high haze. The existing diffusion film can be divided into bulk diffusion and surface diffusion according to different mechanisms. The bulk diffusion mainly adds heterogeneous particles in the transparent substrate to produce light diffusion by using the scattering of the particles. The surface diffusion forms optical microstructure on the surface of the transparent substrate by polishing, photolithography, coating or sandblasting process, and forms a directional diffusion surface light source through a large number of light propagation paths.

[0004] For example, in order to improve the uniformity of the emitted light, the diffusion film surface designed by Chinese patent CN1641432A has a columnar lens structure; the microstructure designed by CN101620283B on the surface of the diffusion film is a triangular pyramid type; and the microstructure designed by patent CN201228916Y is a conical shape. The above patents all design different optical microstructures on the surface of the diffusion film to achieve the goal of uniform light, but such structures need to add a small amount of particles in the diffusion film to improve the uniform light performance of the diffusion film through the synergistic effect of the particles and the surface of the microstructure, which undoubtedly increases the production cost and puts forward higher requirements for the processing and forming process of the diffusion film. In addition, the common double-layer lens structure is interlaced, which also produces new defects such as light interference.

[0005] To further simplify the processing technology of the diffusion film, some workers design the surface of the diffusion film into a pyramid and a pyramid-like structure, such as Chinese Patent CN114624799A, which contains a plurality of pyramid-like structures with different apex angles on the surface of the diffusion film, expecting to improve the uniformity of the diffusion film by increasing the light splitting points. This structure can avoid the use of traditional diffusion agents to some extent, but it has little effect on improving the uniformity of the diffusion film. SUMMARY

[0006] The present application provides a diffusion film to solve the above-mentioned problems of the prior art. The diffusion film forms a stacked optical microstructure on the diffusion film. By controlling the light output in the horizontal direction of the stacked microstructure, the light path is controllable, and the light mixing effect between LED light sources is improved, thereby greatly improving the unevenness of the light output surface. In addition, a one-time molding process without adding particles is provided to simplify the production process and reduce production costs.

[0007] To achieve the purpose of the present application, the following techniques are used:

[0008] In one aspect, a diffusion film is provided. The diffusion film has a continuous or discontinuous optical microstructure on the light output surface and / or the light input surface. The optical microstructure has a stacked structure.

[0009] Further, the optical microstructure includes at least one platform.

[0010] The platform has a horizontal direction parallel to the plane.

[0011] The platform has at least one continuous light output peripheral surface.

[0012] The profile of the platform increases / decreases in sequence along the direction perpendicular to the light output surface of the diffusion film, forming a stepped structure, and the projection of the platform at the previous level is located within the profile of the platform at the next level.

[0013] Further, the light output peripheral surface of the platform is a plane, and the number of light output peripheral surfaces of the platform is at least three.

[0014] Further, the light output peripheral surface of the platform is a continuous arc surface, and the number of light output peripheral surfaces of the platform is one.

[0015] Further, the top end of the platform has at least one top platform.

[0016] The peripheral side of the top platform is a conical surface, and the axial direction of the top platform is perpendicular to the light output surface of the diffusion film.

[0017] And / or the top platform is a conical structure, and the height direction of the top platform is perpendicular to the light output surface of the diffusion film.

[0018] Further, the included angle between the bottom end of the top platform and the platform at the top end is 1-89 degrees.

[0019] Further, the optical microstructure protrudes from the light exit surface of the diffusion film and / or is recessed in the light exit surface of the diffusion film.

[0020] Further, the height of the optical microstructure is ≥1 μm.

[0021] The width or diameter of the optical microstructure is ≥1 μm.

[0022] In another aspect, a diffusion film preparation method is provided for the preparation of a diffusion film using a film pressing device, which includes the following steps:

[0023] A lower substrate plate is provided, a plurality of concave molds in a stacked structure are formed on the lower substrate plate, a plurality of air holes are formed on the lower substrate plate, and the lower ends of the air holes are connected to an air pump through a pipeline;

[0024] A lower pressing plate reciprocating up and down is provided, a plurality of convex molds in a stacked structure are formed on the lower wall of the lower pressing plate, the number of the convex molds is consistent with that of the concave molds, and the convex molds and the concave molds have a one-to-one correspondence relationship;

[0025] During the preparation of the diffusion film, the convex molds in a stacked structure on the lower pressing plate act on the diffusion film to form optical microstructures in a stacked structure on the diffusion film.

[0026] Further, the film pressing device includes a conveying mechanism, a film pressing mechanism, and a transmission mechanism.

[0027] The conveying mechanism includes a pair of side plates, a rotating seat is installed on each side plate, a lower substrate roller is rotatably arranged between the side plates, a rotating ring is installed at the upper end of each side plate, the rotating ring is installed on the side plate through a plurality of mounting plates, a rotating disc is rotatably arranged in the rotating ring, four convex plates are circumferentially arranged on the inner side end of each rotating disc, four conveying arc plates are arranged between the rotating discs, the two ends of the conveying arc plate are installed on the convex plate, and the outer wall of the conveying arc plate is in an arc structure. A cross-shaped groove is formed on the outer side end of the rotating disc, a circular groove is formed at the intersection of the groove, four convex blocks are circumferentially arranged on the outer side end of the rotating disc, an inner concave arc groove is formed in the inner wall of the convex block, and the convex block is located on each diagonal line of the groove. One end of the rotating seat is rotatably provided with a first rotating shaft, the inner side end of the first rotating shaft is provided with a first gear, the first gear is engaged with a second gear, the second gear is connected with a second rotating shaft, the outer side end of the second rotating shaft is arranged on the rotating seat, the inner side end of the second rotating shaft is provided with a rotating plate, one end of the rotating plate is formed with a sector plate, the outer wall of the sector plate is in an arc structure, the inner side end of the rotating plate is provided with a push rod, and when the push rod is located in the groove, the rotating disc is used to rotate, and when the sector plate is located in the inner concave arc groove, the rotating disc stops rotating.

[0028] The pressing mechanism comprises a pair of fixed end plates, a lower substrate plate is installed between the fixed end plates, a plurality of concave dies in a stacked structure are formed on the lower substrate plate, a plurality of air holes are formed on the lower substrate plate, the lower ends of the air holes are connected to an air pump through pipelines, the upper ends of each fixed end plate are installed with a pair of mounting pieces in a cross-shaped structure, inner tooth rings are installed on the mounting pieces, third gears are engaged in the inner tooth rings, third shafts are coaxially arranged on the third gears, rotating plates are arranged on the inner side ends of the third shafts, connecting lugs are rotatably arranged on the other ends of the rotating plates, lower pressing plates are installed on the lower ends of the connecting lugs, a plurality of convex dies in a stacked structure are formed on the lower walls of the lower pressing plates, the number of the convex dies is consistent with that of the concave dies, and the convex dies and the concave dies are in one-to-one correspondence, outer connecting plates are arranged on the outer side ends of the third shafts, fourth shafts are arranged on the other ends of the outer connecting plates, the fourth shafts are coaxial with the inner tooth rings, the fourth shafts are rotatably arranged on the mounting pieces, fifth gears are arranged on the outer side ends of the fourth shafts, a sixth gear is engaged between each pair of fifth gears on the same end, the sixth gear is rotatably arranged on the fixed end plate through a driving shaft, a plurality of upward extending guide rods are arranged on the lower pressing plate extending upward, an upper plate is sleeved on the upward extending guide rods, and the two ends of the upper plate are installed on the upper ends of the fixed end plates. The transmission mechanism comprises a motor mounting plate installed on the upper end of the fixed end plate, a motor is installed on the motor mounting plate, the output shaft of the motor is connected to the driving shaft, a driving wheel is arranged on the driving shaft, a driven wheel is arranged on the outer side end of the first shaft, and the driving wheel and the driven wheel are driven through a synchronous belt.

[0029] The above technical solution has the following advantages:

[0030] (1) By introducing at least one square or circular platform in the stacked optical microstructure, the light output area of a single LED lamp is increased by increasing the horizontal light output, thereby increasing the light mixing effect between LED lamps and weakening the dark light band between LED lamps, and finally improving the uniform light effect of the diffusion film.

[0031] (2) The present application prepares a stacked structure of optical microstructures on the diffusion film, uniformly reflects and refracts the light emitted by the light source, solves the problems existing in the prior art, and adopts a method or device for preparing the diffusion film, which can avoid deformation during demolding, and facilitates the transportation of the diffusion film during preparation. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings.

[0033] Figure 1 A perspective view of the optical microstructure shown in Example 2 is shown.

[0034] Figure 2The structural diagram of the optical microstructure shown in Example 3 is shown, wherein Figure (A) is a three-dimensional structural diagram of the optical microstructure without a top platform structure, Figure (B) is a three-dimensional structural diagram of the optical microstructure with a top platform structure, Figure (C) is a simple light path diagram of the optical microstructure without a top platform structure, and Figure (D) is a simple light path diagram of the optical microstructure with a top platform structure.

[0035] Figure 3 The structural diagram of the optical microstructure shown in Example 4 is shown, wherein Figure (A) is a three-dimensional structural diagram of the optical microstructure with a top platform structure, Figure (B) is a three-dimensional structural diagram of the optical microstructure without a top platform structure, Figure (C) is a simple light path diagram of the optical microstructure with a top platform structure, and Figure (D) is a simple light path diagram of the optical microstructure without a top platform structure.

[0036] Figure 4 The structural diagram of the optical microstructure shown in Example 5 is shown, wherein Figure (A) is a three-dimensional structural diagram of the optical microstructure, and Figure (B) is a simple light path diagram of the optical microstructure.

[0037] Figure 5 The size structural diagram of the optical microstructure shown in Example 3 and Example 4 is shown.

[0038] Figure 6 The size structural diagram of the top platform of the optical microstructure and the top end platform shown in Example 3, Example 4 and Example 5 is shown.

[0039] Figure 7 The comparison diagram of the implementation effects of different optical microstructures is shown.

[0040] Figure 8 The schematic diagram of the optical microstructure protruding from the light emitting surface of the diffusion film or the optical microstructure recessed in the light emitting surface of the diffusion film is shown.

[0041] Figure 9 The three-dimensional structural diagram of the film pressing device is shown.

[0042] Figure 10 The three-dimensional structural diagram of the conveying mechanism is shown.

[0043] Figure 11 The first part of the three-dimensional structural diagram of the conveying mechanism is shown.

[0044] Figure 12 The second part of the three-dimensional structural diagram of the conveying mechanism is shown.

[0045] Figure 13 The third part of the three-dimensional structural diagram of the conveying mechanism is shown.

[0046] Figure 14 The three-dimensional structural diagram of the film pressing mechanism is shown.

[0047] Figure 15 A first partial perspective view of the film pressing mechanism is shown. DETAILED DESCRIPTION

[0048] Embodiment 1

[0049] A diffusion film, the light exit surface of the diffusion film has no optical microstructure. This embodiment is a comparative example, used for comparison and reference to the effect of other embodiments.

[0050] Embodiment 2

[0051] As shown in Figure 1 , a diffusion film, the light exit surface or non-light exit surface of the diffusion film has continuous or discontinuous optical microstructure, the optical microstructure is in the form of a pyramid structure. It can be seen that Figure 7 when such a structure of optical microstructure is provided on the light exit surface or / and the light entrance surface of the diffusion film, a certain light mixing effect can be achieved through reflection and refraction of the light rays of the light source, but the boundary between bright and dark areas is clear, so it does not achieve good light mixing and uniformity effect.

[0052] Embodiment 3

[0053] As shown in Figure 2 , a diffusion film, the light exit surface or / and the light entrance surface of the diffusion film has continuous or discontinuous optical microstructure, the optical microstructure is in the form of a stacked structure.

[0054] As shown in Figure 2 Figure (A), specifically, the optical microstructure includes a plurality of platforms, the platforms have planes parallel to each other in the horizontal direction, the platforms have a continuous light exit peripheral surface, the light exit peripheral surface of the platforms is a continuous arc surface, the profile of the platforms increases / decreases in turn along a direction perpendicular to the light exit surface of the diffusion film, and forms a stepped structure, and the projection of the platform at the previous level is located within the profile of the platform at the next level.

[0055] As shown in Figure 2 Figure (B), specifically, the top end of the platform has a top platform, the peripheral side of the top platform is a conical surface, and the axis of the top platform is perpendicular to the light exit surface of the diffusion film.

[0056] Specifically, as shown in Figure 8 , the optical microstructure protrudes from the light exit surface of the diffusion film and / or the optical microstructure is recessed in the light exit surface of the diffusion film.

[0057] From Figure 2 Figures (C) and (D), and in combination with Figure 7As shown in the specific effect diagram shown in the middle, compared with the diffusion film and the stepped pyramid structure of embodiment 1, the diffusion film provided by the embodiment converges the light source to the horizontal direction by using the peripheral surface of the platform, increases the reflection and refraction probability of the light source in the horizontal direction, and significantly improves the light mixing and uniformity effect compared with the ordinary pyramid structure.

[0058] Embodiment 4

[0059] As shown in Figure 3 , a diffusion film has continuous or discontinuous optical microstructures on the light-out surface and / or the light-in surface of the diffusion film, and the optical microstructures have a stacked structure.

[0060] As shown in Figure 3 , specifically, the optical microstructures include at least a plurality of platforms, the platforms have planes parallel to each other in the horizontal direction, the platforms have four continuous light-out peripheral surfaces, and the light-out peripheral surfaces of the platforms are a continuous arc surface or a plane. The profiles of the platforms increase / decrease in turn along the direction perpendicular to the light-out surface of the diffusion film and form a stepped structure, and the projection of the platform at a previous level is located within the profile of the platform at a next level. As shown in Figure 3 , the optical microstructures with the square stepped structure make part of the light rays exit from the side surface of the optical microstructures in the horizontal state through refraction and reflection when the light rays pass through the optical microstructures, thereby playing a directional role on the light path or the light rays, and the more the stacked layers are, the more the parallel light rays are, and the increase of the horizontal light rays improves the light mixing effect between the LED lamps.

[0061] Specifically, the top end of the platform has a top platform, the top platform is a conical structure, and the height direction of the top platform is perpendicular to the light-out surface of the diffusion film. Specifically, refer to Figure 3 , (A) and (D), by setting a square conical structure at the top end of the platform, horizontal light is emitted from the square structure when the LED emits light, thereby significantly improving the light mixing effect.

[0062] Specifically, as shown in Figure 8 , the optical microstructures protrude from the light-out surface of the diffusion film and / or the optical microstructures are recessed in the light-out surface of the diffusion film.

[0063] In order to intuitively describe the embodiment and embodiment 3, the structures involved in the embodiment and embodiment 3 are described as follows.

[0064] As shown in Figure 5As shown in the figure, the platforms in this optical microstructure are named f1, f2, f3, f4, ..., fn. Only f1, f2, f3, and f4 are shown in this figure. The diameter or width of f4 is 'a', where a ≥ 1 μm. The diameter or width of f3 is 'b', and the relationship between the diameter or width of f3 (b) and the diameter or width of f4 (a) is a ≥ b. The diameter or width of f2 is 'c', and the relationship between the diameter or width of f2 (c) and the diameter or width of f3 (b) is b ≥ c. The diameter or width of f1 is 'd', and the relationship between the diameter or width of f2 (c) and the diameter or width of f1 (d) is c ≥ d. The height e of this circular or square-shaped structure is ≥ 1 μm.

[0065] like Figure 6 The diagram shows the structure between the top platform and the top platform, where the angle α between the bottom of the top platform and the top platform is 1-89 degrees.

[0066] Example 5

[0067] A diffusion membrane, the structure of which is as follows Figure 4 As shown in Figure (A), the light-emitting surface and / or light-incident surface of the diffusion film has continuous or discontinuous optical microstructures, which are stacked.

[0068] Specifically, the optical microstructure includes a platform with mutually parallel planes along the horizontal direction and four consecutive light-emitting peripheral surfaces, all of which are planes. The platform's outline increases / decreases sequentially along a direction perpendicular to the light-emitting surface of the diffusion film, forming a stepped structure, with the projection of the upper-level platform lying within the outline of the lower-level platform.

[0069] Specifically, the top of the platform has at least one top platform, which is a conical structure, and the height of the top platform is perpendicular to the light-emitting surface of the diffusion film.

[0070] Specifically, the angle between the bottom of the top platform and the platform at the top is 1-89 degrees.

[0071] Specifically, such as Figure 8 As shown, the optical microstructure protrudes from the light-emitting surface of the diffusion film and / or the optical microstructure is recessed within the light-emitting surface of the diffusion film.

[0072] Combination Figure 7 The content shown in the document and Figure 4 As shown in Figure (B), compared with Example 1, the stepped pyramid structure in the diffusion film uses the peripheral side of the platform to converge the light source to the horizontal direction, which increases the probability of reflection and refraction of the light source in the horizontal direction. Its light mixing and light homogenization effects are significantly improved compared with ordinary pyramid structures.

[0073] In addition, the platform involved in the optical microstructure of the present application can also be other polygons, such as a three-edge polygon, a five-edge polygon, and other polygonal structures, which are not shown in the drawings. It should be noted that regardless of the number of light-emitting peripheral sides of the platform, as long as the light can be propagated in the horizontal direction to increase the light mixing effect, it should be considered as a simple transformation of the present application. As a further optimization, the top of the polygonal platform can also include a corresponding shaped top platform structure.

[0074] By Figure 7 The display diagram of the light mixing effect between different embodiments shows that embodiments 3 to 5 present a better light mixing effect, significantly weakening the dark light band between the LEDs and significantly achieving the uniform light effect.

[0075] Embodiment 6

[0076] As Figure 9 shown, a film pressing device for preparing the diffusion film of the above-mentioned embodiments 2-5 includes a conveying mechanism 2, a film pressing mechanism 3, and a transmission mechanism 4.

[0077] As Figures 10-13 shown, the conveying mechanism 2 includes a pair of side plates 200, each of which is provided with a rotating seat 202. A lower lining roller 201 is rotatably arranged between the side plates 200. The upper end of each side plate 200 is provided with a rotating ring 203, which is mounted on the side plate 200 through a plurality of mounting plates 204. A rotating disc 205 is rotatably arranged in each rotating ring 203. Four convex plates 206 are circumferentially arranged on the inner side end of each rotating disc 205. Four conveying arc plates 210 are arranged between the rotating discs 205. The two ends of each conveying arc plate 210 are mounted on the convex plates 206. The outer wall of the conveying arc plate 210 is in an arc structure. A cross-shaped groove 207 is formed on the outer side end of the rotating disc 205. A circular groove 220 is formed at the intersection of the groove 207. Four convex blocks 208 are circumferentially arranged on the outer side end of the rotating disc 205. An inner recessed arc groove is formed on the inner wall of each convex block 208. Each convex block 208 is located on each diagonal line of the groove 207. One end of the rotating seat 202 is rotatably provided with a first rotating shaft 211. The inner side end of the first rotating shaft 211 is provided with a first gear 212. The first gear 212 is engaged with a second gear 213. The second gear 213 is connected with a second rotating shaft. The outer side end of the second rotating shaft is arranged on the rotating seat 202. The inner side end of the second rotating shaft is provided with a rotating plate 214. One end of the rotating plate 214 is formed with a fan-shaped plate 215. The outer wall of the fan-shaped plate 215 is in an arc structure. The inner side end of the rotating plate 214 is provided with a push rod 216. When the push rod 216 is located in the groove 207, the rotating disc 205 is used to rotate. When the fan-shaped plate 215 is located in the inner recessed arc groove, the rotating disc 205 stops rotating.

[0078] As Figures 14-15As shown, the film pressing mechanism 3 comprises a pair of fixed end plates 300, a lower substrate plate 309 is installed between the fixed end plates 300, a plurality of concave molds in a stacked structure are formed on the lower substrate plate 309, a plurality of air holes are formed on the lower substrate plate 309, the lower ends of the air holes are connected to the air pump through the pipeline, the upper end of each fixed end plate 300 is installed a pair of cross-shaped mounting pieces 303, the mounting pieces 303 are installed with inner tooth rings 304, the inner tooth rings 304 are engaged with third gears 306, the third gears 306 are coaxially provided with third shafts, the inner side ends of the third shafts are provided with rotating plates 307, the other ends of the rotating plates 307 are rotatably provided with connecting lugs 308, the lower ends of the connecting lugs 308 are installed with lower pressing plates 310, a plurality of convex molds in a stacked structure are formed on the lower wall of the lower pressing plates 310, the number of the convex molds is consistent with that of the concave molds, and the convex molds and the concave molds have one-to-one correspondence, the outer side ends of the third shafts are provided with outer connecting plates 305, the other ends of the outer connecting plates 305 are provided with fourth shafts, the fourth shafts are coaxial with the inner tooth rings 304, the fourth shafts are rotatably provided on the mounting pieces 303, the outer side ends of the fourth shafts are respectively provided with fifth gears 302, each pair of fifth gears 302 located at the same end are engaged with a sixth gear 301, the sixth gear 301 is rotatably provided on the fixed end plate 300 through the drive shaft, the lower pressing plates 310 are upwardly extended with a plurality of upward extension guide rods 311, the upward extension guide rods 311 are sleeved with upper plates 312, and the two ends of the upper plates 312 are installed on the upper end of the fixed end plate 300. The transmission mechanism 4 comprises a motor mounting plate 40 installed on the upper end of the fixed end plate 300, a motor 41 installed on the motor mounting plate 40, the output shaft of the motor 41 connected to the drive shaft, a drive wheel 42 provided on the drive shaft, the outer side end of the first shaft 211 provided with a driven wheel 44, and the drive wheel 42 and the driven wheel 44 driven through the synchronous belt 43.

[0079] In operation, the prepared diffusion film is preheated, and then passes through the film pressing mechanism 3. When the diffusion film passes through the film pressing mechanism 3, the lower pressing plates 310 and the lower substrate plate 309 press and form the diffusion film therebetween. During the pressing and forming process, the air pump is needed to pump air, so that the diffusion film is tightly attached to the lower substrate plate 309. When the pressing and forming is completed, the lower pressing plates 310 move upward, and the air pump ventilates the air holes of the lower substrate plate 309, so that the diffusion film attached to the lower substrate plate 309 moves upward, and the pressed and formed optical microstructure is smoothly pulled out of the concave mold. Then, the diffusion film passes through the air cooling or water cooling device to cool and set, and then continues to be conveyed forward under the driving of the conveying mechanism 1.

[0080] When the diffusion film is being transported, the diffusion film is located above the lower backing roller 201. During transportation, the motor 41 drives the first rotating shaft 211 to rotate through the driving wheel 42, the synchronous belt 43 and the driven wheel 44. The rotation of the first rotating shaft 211 drives the first gear 212 to rotate, which in turn drives the second gear 213 to rotate, and the rotation of the second gear 213 drives the rotating plate 214 to rotate. During the rotation of the rotating plate 214, the toggle lever 216 rotates around the axis of the second gear 213, and the toggle lever 216 acts on the side wall of the recess 207 in the cross-shaped structure during the rotation, thereby causing the rotating disc 205 to rotate around its axis. When the toggle lever 216 loses the force acting on the side wall of the recess 207, the fan-shaped plate 215 is in the concave arc groove, and the rotating disc 205 is in a state of stopping rotation. When the toggle lever 216 acts on the side wall of the recess 207 and causes the rotating disc 205 to rotate, the transport arc plate 210 mounted on the rotating disc 205 interacts with the lower backing roller 201, and the diffusion film is transported forward under the rotation of the transport arc plate 210. In this way, the rotating disc 205 can rotate periodically, thereby achieving periodic pushing of the diffusion film, providing sufficient time for the pressing molding of the optical microstructure on the diffusion film, and facilitating the subsequent winding operation of the diffusion film. The rotating ring 203 can cause the rotating disc 205 to rotate stably.

[0081] When the diffusion film optical microstructure is being formed, the motor 41 drives the driving shaft to rotate, which in turn drives the sixth gear 301 to rotate. The rotation of the sixth gear 301 drives the two fifth gears 302 to rotate, and the rotation of the fifth gears 302 drives the outer connecting plate 305 to rotate around one end of the fifth gear 302. The rotation of the outer connecting plate 305 drives the third gear 306 to rotate, which in turn causes the rotating plate 307 to rotate. At the same time, the rotating plate 307 also moves around the inner tooth ring 304. This movement causes the lower pressing plate 310 to move up and down reciprocally. When the lower pressing plate 310 moves downward, it interacts with the lower substrate plate 309 and completes the pressing molding of the diffusion film. The upper extension guide rod 311 plays a guiding and limiting role in the movement of the lower pressing plate 310, thereby ensuring the stability and accuracy during the forming process.

[0082] Example 7

[0083] A diffusion film preparation method using the film pressing device provided in Example 6 to prepare the diffusion films of Examples 2-5, comprising the following steps:

[0084] A lower substrate plate 309 is provided, a plurality of concave molds in a stacked structure are formed on the lower substrate plate 309, and a plurality of air holes are formed on the lower substrate plate 309, and the lower ends of the air holes are connected to an air pump through a pipeline.

[0085] A lower pressing plate 310 reciprocating up and down is provided, a plurality of convex molds in a stacked structure are formed on the lower wall of the lower pressing plate 310, and the number of the convex molds is consistent with that of the concave molds, and the convex molds and the concave molds are in one-to-one correspondence.

[0086] During the preparation of the diffusion film, the convex molds in a stacked structure on the lower pressing plate 310 act on the diffusion film to form optical microstructures in a stacked structure on the diffusion film.

[0087] The above description is only the preferred embodiments of the present application, and is not intended to limit the present application. Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application belong to the scope of the claims of the present application and the equivalent technologies thereof, the present application is also intended to include these modifications and variations.

Claims

1. A method for preparing a diffusion film, characterized by, The application relates to a preparation method of a diffusion film, and a film pressing device. The application comprises the following steps: a lower substrate plate (309) is provided, a plurality of concave molds in a stacked structure are formed on the lower substrate plate (309), a plurality of air holes are formed on the lower substrate plate (309), and the lower ends of the air holes are connected to an air pump through pipelines; a lower pressing plate (310) reciprocating up and down is provided, a plurality of convex molds in a stacked structure are formed on the lower wall of the lower pressing plate (310), the number of the convex molds is consistent with that of the concave molds, and the convex molds and the concave molds are in one-to-one correspondence; during the preparation of the diffusion film, the convex molds in a stacked structure on the lower pressing plate (310) act on the diffusion film to form optical microstructures in a stacked structure on the diffusion film; the film pressing device comprises a conveying mechanism (2), a film pressing mechanism (3) and a transmission mechanism (4); the conveying mechanism (2) comprises a pair of side plates (200), a rotating seat (202) is arranged on each of the side plates (200), a lower substrate roller (201) is rotatably arranged at the lower ends of the side plates (200), a rotating ring (203) is arranged at the upper ends of the side plates (200), the rotating ring (203) is arranged on the side plates (200) through a plurality of mounting plates (204), rotating discs (205) are rotatably arranged in the rotating ring (203), four convex plates (206) are circumferentially arranged at the inner side ends of each of the rotating discs (205), four conveying arc plates (210) are arranged between the rotating discs (205), and the two ends of the conveying arc plates (210) are arranged on the convex plates (206). The outer side ends of the rotating discs (205) are provided with recesses (207) in a cross structure, a circular groove (220) is formed at the intersection of the recesses (207), four convex blocks (208) are circumferentially arranged at the outer side ends of the rotating discs (205), and an inner recessed arc groove is formed in the inner wall of each of the convex blocks (208). One end of the rotating seat (202) is rotatably provided with a first rotating shaft (211), the inner side end of the first rotating shaft (211) is provided with a first gear (212), the first gear (212) is engaged with a second gear (213), the second gear (213) is connected with a second rotating shaft, the outer side end of the second rotating shaft is arranged on the rotating seat (202), the inner side end of the second rotating shaft is provided with a rotating plate (214), one end of the rotating plate (214) is formed with a sector plate (215), the outer wall of the sector plate (215) is in an arc structure, the inner side end of the rotating plate (214) is provided with a pushing rod (216), when the pushing rod (216) is located in the recess (207), the rotating disc (205) is used for being pushed to rotate, and when the sector plate (215) is located in the inner recessed arc groove, the rotating disc (205) stops rotating. The film pressing mechanism (3) comprises a pair of fixed end plates (300), a lower substrate plate (309) is installed between the fixed end plates (300), a plurality of concave molds in a stacked structure are formed on the lower substrate plate (309), a plurality of air holes are formed on the lower substrate plate (309), the lower ends of the air holes are connected to an air pump through pipelines, the upper ends of each fixed end plate (300) are provided with a pair of cross-shaped mounting pieces (303), the mounting pieces (303) are provided with inner tooth rings (304), the inner tooth rings (304) are engaged with third gears (306), the third gears (306) are coaxially provided with third rotating shafts, the inner sides of the third rotating shafts are provided with rotating plates (307), the other ends of the rotating plates (307) are rotatably provided with connecting convex plates (308), the lower ends of the connecting convex plates (308) are provided with lower pressing plates (310), a plurality of convex molds in a stacked structure are formed on the lower wall of the lower pressing plate (310), the number of the convex molds is the same as that of the concave molds, the convex molds and the concave molds are in one-to-one correspondence, the outer sides of the third rotating shafts are provided with outer connecting plates (305), the other ends of the outer connecting plates (305) are provided with fourth rotating shafts, the fourth rotating shafts are coaxial with the inner tooth rings (304), the fourth rotating shafts are rotatably arranged on the mounting pieces (303), the outer sides of the fourth rotating shafts are provided with fifth gears (302), each pair of fifth gears (302) located at the same end is engaged with a sixth gear (301), the sixth gears (301) are rotatably arranged on the fixed end plates (300) through driving shafts, the lower pressing plate (310) is upwardly extended to be provided with a plurality of upward extending guide rods (311), the upward extending guide rods (311) are provided with upper plates (312), the two ends of the upper plates (312) are arranged on the upper ends of the fixed end plates (300). The transmission mechanism (4) comprises a motor mounting plate (40) arranged on the upper end of the fixed end plate (300), the motor mounting plate (40) is provided with a motor (41), the output shaft of the motor (41) is connected to a driving shaft, the driving shaft is provided with a driving wheel (42), the outer side of the first rotating shaft (211) is provided with a driven wheel (44), the driving wheel (42) and the driven wheel (44) are driven through a synchronous belt (43).

2. The method of claim 1, wherein the diffusion film is prepared by a method comprising: The optical microstructure comprises at least one platform; The platform has planes parallel to each other in the horizontal direction; The platform has at least one continuous light-out peripheral surface; The profile of the platform increases / decreases in turn along the direction perpendicular to the light-out surface of the diffusion film, and forms a stepped structure, and the projection of the platform at the upper level is located within the profile of the platform at the lower level.

3. The method for preparing a diffusion film according to claim 2, characterized in that, The light-out peripheral surface of the platform is a plane, and the number of the light-out peripheral surface of the platform is at least three.

4. The method for preparing a diffusion film according to claim 2, characterized in that, The light-out peripheral surface of the platform is a continuous arc surface, and the number of the light-out peripheral surface of the platform is one.

5. The preparation method of the diffusion film according to claim 2, wherein: The top end of the platform has at least one top platform; The peripheral surface of the top platform is a conical surface, and the axial direction of the top platform is perpendicular to the light-out surface of the diffusion film; The height direction of the top platform is perpendicular to the light-out surface of the diffusion film.

6. The method of claim 5, wherein the diffusion film is prepared by a method comprising: The included angle between the bottom end of the top platform and the platform at the top end is 1-89 degrees.

7. The method of claim 1 or 2, wherein the diffusion film is prepared by a method comprising: The optical microstructures project from the light exit face of the diffusion film and / or the optical microstructures are recessed in the light exit face of the diffusion film. ​ 8. The diffusion film production method according to claim 1 or 2, characterized in that: The height of the optical microstructures is > 1 pm; The width or diameter of the optical microstructures is > 1 pm.

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