Optical function board and manufacturing method thereof

Abstract

The invention discloses an optical function board and a manufacturing method thereof. The optical function board comprises a base material layer; an integrally connected structural layer is arranged above the base material layer; the structure layer is of a plurality of curved surface structures arranged in an array mode. The raw materials are heated and melted, stirred and mixed uniformly, and extruded to obtain a transparent plate; through an impressing process, impressing a structural layer on the surface of the plate by a compression roller to form an optical function plate structure; carrying out physical performance testing and optical performance testing on the optical function board; the base material layer and the structural layer which are integrally connected are prepared from the polystyrene material, the structural layer is directly imprinted through the imprinting process to obtain the curved surface structure, the optical function board is formed, compared with an existing optical film, the optical function board is harder, larger in elastic modulus, higher in stiffness and not prone to wrinkling and bending, and therefore the problem of uneven brightness caused by the optical film is not prone to occurring.

Description

Technical Field

[0001] The present invention relates to the technical field of LED screen production, and in particular to an optical functional board and a production method thereof. Background Art

[0002] The backlight optical film of the LCD screen plays a vital role in the brightness and uniformity of the display screen, among which the Microlens film is widely used in the industry. The existing Microlens film structure is mainly composed of PET as a substrate. The existing Microlens film structure is obtained by coating resin on the PET surface and curing the resin with UV irradiation when the Microlens film structure is imprinted.

[0003] Taking polyethylene terephthalate (PET) as the substrate, the molding process is as follows: first pre-dry the PET resin slices, then extrude the amorphous thick slices through a T-die at 280°C in the extruder, quench through a cooling drum or coolant, and then stretch the thick slices in both the longitudinal and transverse directions through a tentering machine to make a PET film. The film after longitudinal and transverse stretching also needs to be heat-set to eliminate the film deformation caused by stretching and make a film with good thermal stability. After the film is made, it is rolled up, and the rolled film is transported to the surface microstructure molding line for unwinding. The surface of the film is coated with glue, and the target microstructure mold roller is used to emboss and cure the glue to form a surface microstructure. Due to the many process stages and the long production line, it is difficult to integrate into one-piece processing.

[0004] The Young's modulus of PET material is 2-2.5GPa, and the material is soft and has low stiffness. The low stiffness makes it more prone to uneven brightness due to bending after being assembled in the backlight module, and an additional hook structure needs to be designed in the backlight module to fix the diaphragm pull ears. Multi-layer stacking makes the assembly process more complicated. For example, the electrostatic adsorption between the diaphragms makes it inconvenient to take and adjust the diaphragms. There are more steps in assembling multi-layer diaphragms, and the probability of defects caused by operations will be higher. The assemblers need to have a certain level of assembly proficiency and the cost is higher. The resin used in the production process generally has a refractive index of 1.49 to 1.5, which has limited focusing effect on large-angle incident light, and the value is different from the refractive index of the substrate PET film, resulting in large optical path losses. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose an optical functional plate and a manufacturing method thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: an optical functional plate, comprising:

[0007] substrate layer;

[0008] An integrated structural layer is disposed above the substrate layer;

[0009] The structural layer is a plurality of curved surface structures arranged in an array.

[0010] As a further description of the above technical solution: a plurality of the curved surface structures are arranged in a regular hexagonal array, and the curved surface structure is a hemispherical structure.

[0011] As a further description of the above technical solution: the cross-section of the curved surface structure is elliptical or spherical. When the cross-section of the curved surface structure is elliptical, the long diameter is 25-35 μm and the short diameter is 5-15 μm.

[0012] As a further description of the above technical solution: when the cross-section of the curved surface structure is elliptical, the long diameter is 26-30 μm and the short diameter is 11-13 μm.

[0013] As a further description of the above technical solution: the thickness of the structural layer is 5-15 μm.

[0014] As a further description of the above technical solution: the overall thickness of the substrate layer and the structural layer is 0.10-1.00 mm, preferably 0.30-0.40 mm.

[0015] As a further description of the above technical solution: the materials of the substrate layer and the structural layer are mainly polystyrene, polycarbonate, polymethyl methacrylate or styrene-methyl methacrylate copolymer.

[0016] A method for manufacturing an optical functional plate, the method being applicable to the optical functional plate described in any one of the above technical solutions, comprising:

[0017] S1: heating and melting the raw materials, stirring and mixing them, and extruding them to obtain a transparent sheet;

[0018] S2: Through the embossing process, the pressing roller embosses the surface of the plate to prepare the structural layer, thereby forming an optical functional plate structure;

[0019] S3: Perform physical performance test and optical performance test on the optical functional board.

[0020] As a further description of the above technical solution: in step S1, it also includes,

[0021] S11: adding an anti-aging additive and resin toughening particles to the raw materials and heating and melting them together to form a mixed material;

[0022] S12: stirring the mixed material, and extruding the mixed material to form the transparent plate.

[0023] As a further description of the above technical solution: a soft mold or hard mold pressing roller is used, and the surface of the pressing roller is provided with textures complementary to the shape of the structural layer, and the structural layer is directly formed during the stamping process of the plate.

[0024] As a further description of the above technical solution: a time interval is set, and after the optical functional plate is formed by embossing, the optical functional plate is cooled down, and after the time interval, the optical functional plate is subjected to a physical property test and an optical property test.

[0025] The above technical solution has the following advantages or beneficial effects:

[0026] 1. Polystyrene material is used to prepare an integrated substrate layer and a structural layer. The structural layer is directly embossed through an embossing process to obtain a curved structure to form an optical functional plate. Compared with the existing optical film, it is harder, has a larger elastic modulus, and has a higher stiffness. It is not easy to wrinkle or bend, so it is not easy to cause uneven brightness.

[0027] 2. Compared with existing optical films, it is harder and can be assembled smoothly without the need for a specially designed tight fixing structure like existing films, saving design costs and reducing assembly difficulty.

[0028] 3. Directly print on the surface of the structural layer, there is no optical path loss caused by different refractive indices of different materials, the brightness is higher under the same surface structure conditions, and there is no need to additionally process the resin glue. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0030] Figure 1 A schematic diagram of the structure of the optical functional plate proposed by the present invention;

[0031] Figure 2 A microscopic view of the optical functional plate proposed by the present invention;

[0032] Figure 3 The process of the production method proposed by the present invention Figure 1 ;

[0033] Figure 4 The process of the production method proposed by the present invention Figure 2 ;

[0034] Figure 5 It is a schematic diagram of the optical performance test in the present invention.

[0035] Legend:

[0036] 1. Base material layer; 2. Structural layer; 21. Curved surface structure. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments 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 creative work are within the scope of protection of the present invention.

[0038] The purpose of this patent is to provide an optical functional plate and its production method, so as to solve the problems of low film stiffness, low refractive index of resin glue, high processing cost, and optical path loss caused by different refractive indices between resin glue and substrate film.

[0039] Example 1

[0040] Reference Figure 1-Figure 2 An embodiment of the present invention provides an optical functional plate, comprising: a substrate layer 1; an integrated structural layer 2 is arranged above the substrate layer 1; the structural layer 2 is a plurality of curved structures 21 arranged in an array.

[0041] The plurality of curved surface structures 21 are arranged in a regular hexagonal array, and may also be in a quadrilateral, pentagonal or other array shapes. The curved surface structure 21 is a hemispherical structure.

[0042] The cross section of the curved surface structure 21 is elliptical or spherical. When the cross section of the curved surface structure 21 is elliptical, the long diameter is 26-30 μm and the short diameter is 11-13 μm.

[0043] The thickness of the structural layer 2 is 5-15 μm.

[0044] The overall thickness of the substrate layer 1 and the structural layer 2 is 0.30-0.40 mm.

[0045] The materials of the substrate layer 1 and the structural layer 2 are mainly polystyrene, polycarbonate, polymethyl methacrylate or styrene-methyl methacrylate copolymer. Preferably, polystyrene (PS) optical plastic is used as the raw material. PS material has a lower cost than PET material to achieve higher stiffness. The raw material comes from Jiangsu Saibaolong Petrochemical Co., Ltd. The substrate layer 1 and the structural layer 2 are integrally connected and prepared using polystyrene material. The structural layer 2 is directly embossed by a stamping process to obtain a curved surface structure 21 to form an optical functional plate. Compared with the existing optical film, it is harder, has a larger elastic modulus, has a higher stiffness, is less prone to wrinkles and bends, and is therefore less prone to uneven brightness caused by wrinkles and bends. Compared with the existing optical film, it is harder and can achieve smooth assembly without the need to specially design a tight fixing structure like the existing diaphragm, saving design costs and reducing assembly difficulty.

[0046] Directly print on the surface of the structural layer, there is no light path loss caused by different refractive indices of different materials, the brightness is higher under the same surface structure conditions, and there is no need for additional processing of the resin glue.

[0047] Reference Figure 3 , also includes an embodiment of a method for manufacturing an optical functional plate, the manufacturing method is applicable to any optical functional plate in the above technical solutions, comprising:

[0048] S1: heating and melting the raw materials, stirring and mixing them, and extruding them to obtain a transparent sheet;

[0049] S2: Through the embossing process, the pressing roller embosses the surface of the plate to prepare the structural layer, thereby forming an optical functional plate structure;

[0050] S3: Perform physical performance test and optical performance test on the optical functional board.

[0051] In this embodiment, the raw material is heated to reach its melting point or softening point and converted into a flowable amorphous state. After the raw material is hot-melted, it is stirred by a stirring device to evenly mix the various components. The molten raw material that has been stirred and evenly mixed is transported to an extruder and extruded through a die of a specific shape to form a sheet shape. The screw speed, temperature distribution and die design of the extruder will affect the quality and performance of the sheet. The screw speed determines the extrusion speed of the raw material, which in turn affects the production efficiency of the sheet; the temperature distribution must ensure that the raw material always maintains good fluidity during the extrusion process to avoid local overheating or overcooling. The shape of the die determines the cross-sectional shape of the sheet. For the preparation of transparent sheets, the internal flow channel design of the die must ensure that the raw material can be evenly extruded to obtain a sheet with uniform thickness.

[0052] The surface of the pressing roller is pre-engraved with a pattern or texture corresponding to the required structural layer 2. When the pressing roller contacts the plate and applies pressure, the surface of the plate undergoes plastic deformation under the action of pressure, thereby preparing a structural layer 2 on the surface of the plate. The structural layer prepared by the embossing process gives the plate a specific optical function, thereby forming an optical functional plate structure. For example, the prepared microlens array structure can converge light and improve the utilization efficiency of light; the prism structure is used to change the propagation direction of light to achieve the collimation or splitting function of the light beam.

[0053] Conduct physical performance tests on optical functional boards, including but not limited to stiffness test and impact test; optical performance test is crucial to evaluate the quality and performance of optical functional boards, and the main test items include center brightness and uniformity.

[0054] Reference Figure 4 In step S1, it also includes:

[0055] S11: adding an anti-aging additive and resin toughening particles to the raw materials and heating and melting them together to form a mixed material;

[0056] S12: The mixed material is stirred and extruded to form a transparent plate.

[0057] In this embodiment, the raw materials, anti-aging additives and resin toughening particles are heated together to make them reach their respective melting points or softening points, and gradually merge to form a uniform mixture. The heating equipment can be various types of heating furnaces, heating sections of extruders, etc., and heat is provided by heat transfer oil, electric heating, etc. Stirring is performed during the heating process to promote uniform mixing of the components, avoid local overheating or overcooling, and ensure the uniformity of the quality of the mixture.

[0058] The stirred mixed material is transported to the extrusion port and extruded from the die head through extrusion to form a transparent sheet. During the extrusion process, the rotation of the screw pushes the material forward and exerts pressure on the material, causing it to flow and form in the die head.

[0059] A soft or hard die pressing roller is used, and the surface of the pressing roller is provided with patterns complementary to the shape of the structural layer, so that the structural layer is directly formed during the pressing process of the plate.

[0060] In this embodiment, one of the embossing processes is to process the mold structure of the structural layer 2 on the surface of the pressure roller by etching or laser engraving, etc., to obtain a mold roller, and use the mold roller to directly emboss and solidify to obtain the structural layer 2. This is a hard mold embossing process. However, the mold roller has a high processing cost, a long processing time, and a high maintenance cost after wear, which makes the production cost of directly using the mold roller for embossing too high. Another method is to process the mold structure of the structural layer 2 on the surface of the pressure roller, use the mold roller to emboss a resin to form a diaphragm with a complementary structure to the structural layer 2, use this diaphragm as the mold of the structural layer 2, and use the pressure roller to emboss to form the required structural layer 2. This is a soft mold embossing process, and it is preferred to use a soft mold process to emboss the structural layer 2.

[0061] A time interval is set, and after the optical functional board is formed by embossing, the optical functional board is cooled down, and after the time interval, the optical functional board is subjected to a physical property test and an optical property test.

[0062] In this embodiment, after the stamping is completed, the optical functional plate needs to be cooled so that it can be solidified from an amorphous state. After a set time interval, the optical functional plate can be restored to room temperature. The cooling can be done by natural cooling or air cooling. The time interval can be set according to the actual material and hot melt temperature.

[0063] Comparative Example 1:

[0064] Since Microlens films on the market are generally combined with prismatic brightness enhancement films to form MOP films, common MOP films are used as comparative examples in this group. Under the same backlight conditions, the center brightness and uniformity are compared with Example 1 superimposed with ordinary prismatic brightness enhancement films.

[0065] Comparative Example 2:

[0066] A Microlens film made of PET material with a thickness of 0.30-0.40 mm was selected for physical property testing to compare performance differences. The PS plastic plate with structural layer 2 prepared in Example 1 and the PET film selected in Comparative Example 2 were tested for physical properties under the same experimental conditions.

[0067] 1. Comparison of physical performance tests

[0068] The samples of Example 1 and Comparative Example 2 were tested for physical properties. The bending stiffness tester CV-8550S was used to test the stiffness according to GB / T 2679.3. Sample preparation: 80*38mm samples were prepared, with 3 pieces in the horizontal direction of the same structure and 3 pieces in the vertical direction of the same structure. Experimental conditions: bending length 50mm, bending angle 15°. Test according to the operating method of the bending stiffness tester, test 3 groups, and calculate the average value. The experimental results are shown in Table 1.

[0069]

[0070] Table 1

[0071] As shown in Table 1, the average stiffness of the PS optical functional plate in Example 1 in the horizontal direction is 11.33, and the average stiffness in the vertical direction is 10.793. The average stiffness of the PET film in Comparative Example 2 in the horizontal direction is 3.947, and the average stiffness in the vertical direction is 3.807. Example 1 has a higher stiffness, and a high stiffness is not easy to bend.

[0072] 2. Optical test comparison

[0073] Optical tests were performed on Example 1 and Comparative Example 1. A TCL 55T8E TV without the LCD screen was used as the backlight module, and the spectral color luminance meter SRC-200S was used to test the center coordinate brightness and uniformity. Experimental conditions: A 1.0 mm ordinary PS diffuser (hereinafter referred to as the lower diffuser) was placed on the surface of the lamp bead, and the sample was covered on it as a test structure. The lens was placed vertically close to the sample surface, and the brightness was obtained by testing. The center position of the positioning module was tested to obtain the center brightness. According to the 9-point uniformity test method (refer to Figure 5 ) Test the brightness of 9 positions respectively and calculate the uniformity.

[0074] Uniformity = minimum brightness / maximum brightness * 100%

[0075] The test results are shown in Table 2:

[0076]

[0077] Table 2

[0078] As can be seen from Table 2, the optical functional plate combined with the prism brightness enhancement film and the downward expansion of this embodiment has a brightness uniformity of 70.06%, and the common MOP film on the market has a brightness uniformity of 70.72% when combined with the downward expansion. The center brightness of the optical functional plate, prism brightness enhancement film and downward expansion is 6283.1, and the average brightness is 5109.93, while the center brightness of MOP+downward expansion is 5768, and the average brightness is 4770.37. Therefore, it can be seen that under the same conditions, the optical functional plate of this embodiment can achieve a higher brightness than the existing film while achieving almost the same brightness uniformity.

[0079] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical functional plate, characterized in that: include: A substrate layer (1); An integrally connected structural layer (2) is provided above the substrate layer (1); The structural layer (2) is a plurality of curved surface structures (21) arranged in an array.

2. The optical functional plate according to claim 1, characterized in that: A plurality of the curved surface structures (21) are arranged in a regular hexagonal array, and the curved surface structure (21) is a hemispherical structure.

3. The optical functional plate according to claim 1, characterized in that: The cross section of the curved surface structure (21) is elliptical or spherical. When the cross section of the curved surface structure (21) is elliptical, the long diameter is 25-35 μm, and the short diameter is 5-15 μm.

4. The optical functional plate according to claim 1, characterized in that: The thickness of the structural layer (2) is 5-15 μm.

5. The optical functional plate according to claim 1, characterized in that: The overall thickness of the substrate layer (1) and the structural layer (2) is 0.10-1.00 mm.

6. The optical functional plate according to claim 1, characterized in that: The materials of the substrate layer (1) and the structural layer (2) are mainly polystyrene, polycarbonate, polymethyl methacrylate or styrene-methyl methacrylate copolymer.

7. A method for manufacturing an optical functional plate, characterized in that: The manufacturing method is applicable to the optical functional plate according to any one of claims 1 to 6, comprising: S1: heating and melting the raw materials, stirring and mixing them, and extruding them to obtain a transparent sheet; S2: Through the embossing process, the pressing roller embosses the surface of the plate to prepare the structural layer, thereby forming an optical functional plate structure; S3: Perform physical performance test and optical performance test on the optical functional board.

8. The method according to claim 7, characterized in that: In step S1, it also includes: S11: adding an anti-aging additive and resin toughening particles to the raw materials and heating and melting them together to form a mixed material; S12: stirring the mixed material, and extruding the mixed material to form the transparent plate.

9. The method according to claim 7, characterized in that: A soft mold or hard mold pressing roller is used, and the surface of the pressing roller is provided with patterns complementary to the shape of the structural layer, so that the structural layer is directly formed during the stamping process of the plate.

10. The manufacturing method according to claim 7, characterized in that: A time interval is set, and after the optical functional plate is formed by embossing, the optical functional plate is cooled down, and after the time interval, a physical property test and an optical property test are performed on the optical functional plate.

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