TWI417577B - Light transfer plate with light structure and light guide plate - Google Patents

Description

Micro-structured light diffusing plate and light guide plate

The present invention relates to an optical plate, particularly, for example, a diffusing plate, or other optical plate having different optical effects, and is a structural optical plate having a surface having a microstructure and a thickness of the plate itself much larger than the thickness of the microstructure thereon. An optical plate with a high transfer rate is achieved.

Referring to FIG. 1 , an optical plate structure of a conventional backlight module is disclosed. The micro-structured optical plate is stacked by using a co-extrusion process, and mainly comprises a substrate 7 and a plurality of microstructures formed on the substrate 7 . 8. Each microstructure 8 includes a first protrusion 81 and a second protrusion 91 above the first protrusion 81. The first convex portion 81 and the second convex portion 91 are respectively composed of a first thermoplastic resin and a second thermoplastic resin to form an optical structure having a light diffusion effect and/or a light guiding effect, for example, a zigzag shape. The structure is either a lenticular lens structure or a diffusion layer structure having a uniform light effect. However, since the substrate 7 has a considerable thickness with respect to the second convex portion 91, and the second thermoplastic resin is in a high viscosity state when co-extruded, the optical plate is formed regardless of the molding method using a stamper or a roller mold. The structural characteristics of the structure cannot obtain a better microstructure transfer rate, that is, the second thermoplastic resin is not easily pushed into the depth of the cavity to accurately form the second protrusion, so the top of the second protrusion is often incompletely formed. The optical properties of the original optical plate could not be achieved. Taking a light diffusing plate as an example, if a predetermined microstructure shape cannot be formed, the effect of light diffusion and atomization is reduced, and if it is used for light guiding, the brightness effect is weakened.

Therefore, it is an object of the present invention to provide a light diffusing plate having a special microstructure formed by different resin materials, which can improve the transfer rate of the microstructure and obtain a microstructure close to a predetermined pattern. Optical properties and can reduce the production cost of optical sheets.

Therefore, the microstructured light diffusing plate of the present invention comprises a substrate, a plurality of microstructures disposed on the substrate, and a light diffusing agent, each of the microstructures including a first convex portion integrally connected to the substrate, And a second protrusion adjacent to the first protrusion in a direction away from the substrate, the substrate and the first protrusion are formed by a first resin material, and the first resin material comprises a thermoplastic resin, the first A convex portion has a convex interface formed on the substrate and formed by the connection surface with the second convex portion, and a first apex at the interface of the convex portion. The second convex portion is formed of a second resin material, the second resin material includes a photosensitive resin, and the second convex portion has an outer surface spaced apart from the convex portion interface of the first convex portion, and one bit is The second apex on the outer surface, the light diffusing agent is added to the first resin material and/or the second resin material.

Defining a vertical distance between a second vertex of the second convex portion to a line connecting the lowest points of the first convex portion to D1, and a vertical line connecting the first vertex of the first convex portion to a line connecting the lowest points of the two convex portions The distance is D2, and D2/D1 is between 0.1 and 0.9, and the minimum vertical distance between the outer surface of the second convex portion and the convex portion interface of the first convex portion is less than 5 μm.

Another object of the present invention is to provide a light guide plate having a microstructure, which is substantially the same as the light diffusing plate, except that the second apex of the second convex portion is the lowest on both sides of the first convex portion. The vertical distance between the points is D1', and the vertical distance between the first vertex of the first convex portion and the lowest point on both sides is D2', and D2'/D1' is between 0.1 and 0.7.

The distance between the microstructures of the present invention is not limited, and the microstructures may or may not be connected to each other, but it is preferable to connect them. The size of the microstructure depends on the requirements. The height of the microstructure is between 50 and 1000 microns (μm), and the distance between the highest points of the microstructure (called Pitch) is between 50 and 700 microns.

In the present invention, the substrate and the first convex portion are composed of a thermoplastic resin material, and the first convex portion may be formed by being convexly pressed by the substrate after being pressed, and the manner of pressing is not limited, and a stamper may be used. Stamper), or roller mode and other transfer methods. The second convex portion is connected above the first convex portion, and the space of the microstructure is filled with the second convex portion except the first convex portion protruding upward, and the mold for forming the microstructure is formed. Each of the second convex portions can be separately closed, so that the high-flow photosensitive resin material forming the second convex portion is sufficiently filled into the depth of the cavity of the mold, so that the microstructure of the line can be made closer to the predetermined type. State, in order to achieve high transfer rate, and to obtain the optical properties of demand.

The minimum vertical distance between the outer surface of the second convex portion of the present invention and the convex portion interface of the first convex portion is less than 5 μm, preferably less than 3 μm, and most preferably less than 2 μm, so that a high transfer rate can be achieved. structure.

The substrate and the first convex portion of the present invention are preferably composed of a thermoplastic resin material having a transparent property, and specific examples of the thermoplastic resin are: (meth) acrylate resin, polystyrene resin, and poly Carbonate resin, methyl methacrylate-styrene copolymer, acrylonitrile-styrene copolymer, polyethylene terephthalate. The second convex portion is composed of a photosensitive resin material, which must have both good fluidity and easy hardening after being irradiated by a specific light source, that is, cross-linking after light irradiation (Cross- Linking) a resin material which is hardened by reaction, and is specifically an ultraviolet light photosensitive resin which can be hardened by irradiation with ultraviolet light (UV light), an infrared light photosensitive resin which can be hardened by irradiation with infrared light (IR), or can be subjected to A halogen photo-sensitive resin which is hardened by halogen light irradiation. The photosensitive resin material is preferably an ultraviolet light photosensitive resin, and the composition thereof is not limited. Specific examples include: (a) Acrylic resin, which is used in an amount of 40% by weight to 50% by weight; (b) Free radical photo-initiator is used in an amount of 5 wt% to 15 wt%, and specific examples of the radical photoinitiator are Trimethyl Benzoyl Phosphine Oxide (TPO), 2-Methyl- 1-[4-(Methylthio) phenyl]-2-Morpholino Propan-1-one (Ciba Irgacure 907), Isothioxanthone (ITX), or a combination of these; (c) Reactive acrylic cross-linking resin (Reactive Acrylic cross-linking resin, which is used in an amount of 40% by weight to 50% by weight, and specific examples of the reactive acrylic crosslinking resin are Di-Trimethylolpropane Tetraacrylate (SR-355), Dipentaerythritol Monohydroxy Pentaacrylate (SR-399), Ethoxylated Bisphenol A Diacrylate (SR-349), or a combination of these.

The thermoplastic resin material and the photosensitive resin material may be simultaneously or separately added with a light diffusing agent, the light diffusing agent may be inorganic fine particles or organic fine particles, and the inorganic fine particles such as barium sulfate (BaSO4), titanium dioxide (TiO2) and the like; and the organic fine particles For example, fine particles such as polystyrene resin, (meth)acrylic resin, or organic decane resin.

The ratio of the aforementioned D2/D1 of the present invention is between 0.1 and 0.9. If the ratio is less than 0.1, that is, the photosensitive resin material used for the second convex portion is used in a large amount, the thermoplastic resin used for the first convex portion is used less because the price of the photosensitive resin is much larger than the price of the thermoplastic resin. Therefore, the object of the present invention for reducing costs cannot be achieved.

In the optical plate having a microstructure of the present invention, the thickness of the optical plate is preferably from 0.2 to 5 mm, more preferably from 0.3 to 3 mm, for the purpose of forming a light diffusion plate. Further, in order to form the light guide plate, the thickness of the optical plate is preferably from 0.2 to 10 mm, more preferably from 0.3 to 8 mm. The thickness of the optical plate refers to the highest point of the microstructure on the substrate to the other vertical distance between the substrate and the microstructured surface.

The manufacturing method of the present invention can be carried out by compression molding. First, a stamper mold having a plurality of transfer microstructures is prepared, and a mold hole is commonly defined between the transfer microstructures, and the thermoplastic resin and the light added as needed are prepared. The diffusing agent is used as a raw material to form a substrate having a specific thickness, and then a layer of photosensitive resin material is coated on the substrate, and the thermoplastic resin is heated by the substrate to be softened, and then the stamping die is pressed into the surface. The substrate of the photosensitive resin is simultaneously extracted, so that the photosensitive resin is sufficiently filled into the cavity and the photosensitive resin is hardened and molded, and finally the mold is removed, thereby obtaining the microstructured light diffusion of the present invention. Board or light guide.

The microstructure of the present invention is not limited in shape, and the microstructure cross-sectional shape may be a prism lens, a Lenticular lens, a Fresnel lens or the like.

The method for measuring the microstructure transfer rate of the present invention comprises: taking a long strip sample having a microstructure of one side of the optical plate and having a width of about 1 cm, and measuring the microstructure height and the transfer microstructure of the optical plate under an optical microscope. The height ratio is preferably 95% or more, more preferably 97% or more, and most preferably 99% or more.

The effect of the invention is that the minimum vertical distance between the outer surface of the second convex portion and the convex portion of the first convex portion is less than 5 μm, and the first convex portion and the second convex portion are used with different flows. The resin raw material enables the molding die to independently seal each of the second convex portions, and allows the high-flow photosensitive resin material forming the second convex portion to be sufficiently filled into the deep cavity of the mold, so that not only the formed micro-form The structure is closer to the predetermined type, and the high transfer rate and the desired optical properties are obtained, and the effect of reducing the cost of producing the optical plate can be achieved.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of FIG.

Before the present invention is described in detail, it is noted that in the following description, similar elements are denoted by the same reference numerals.

<Preparation method of light diffusion plate with microstructure according to the present invention>

Referring to Figures 2 and 3, a first preferred embodiment of the present invention utilizes a forming apparatus 5 for fabricating a light diffusing plate having a microstructure, the forming apparatus 5 including a stamper die 51, and a lighting unit 53. The stamper die 51 has a plurality of adjacently arranged transfer microstructures 512, and the transfer microstructures 512 collectively define a cavity 511. Further, a substrate 1 having a thickness of 1.3 mm is formed from the first resin polystyrene and the organic siloxane oxide fine particle light diffusing agent, and the substrate 1 is coated with a layer of ultraviolet light photosensitive resin raw material 6 (including an acrylic resin). And the radical photoinitiator), and since the substrate 1 is formed of a transparent resin, the light emitted from the illumination unit 53 located below it can be allowed to illuminate through the substrate 1 to cause the photosensitive resin material 6 to start to harden on the substrate 1. The substrate 1 is softened by heating, and a stamper 51 having a plurality of transfer microstructures is pressed into the substrate 1 coated with the ultraviolet photosensitive resin raw material 6, and the excess gas is extracted to cause ultraviolet rays to start the hardening reaction. The photo-sensitive resin raw material 6 is filled in the entire cavity 511. After the hardening reaction is completed, the stamper mold 51 is removed to obtain a light-diffusing sheet of the present invention having a thickness of 1.5 mm.

<Structure of Light-Diffusing Plate with Microstructure of the Invention>

The structure of the light diffusing plate obtained by the aforementioned preparation method will be described below. Referring to Fig. 4, the light diffusing plate comprises the substrate 1, and a plurality of microstructures 2 located on the substrate 1 and adjacent to each other. Each microstructure 2 includes a first protrusion 21 connected to the substrate 1 and a second protrusion 31 connected to the first protrusion 21 away from the substrate 1. The first convex portion 21 has a convex portion interface 211 adjacent to the second convex portion 31, and a first apex 212 on the convex portion interface 211. The second convex portion 31 has an outer surface 311 spaced apart from the convex interface 211 of the first convex portion 21, and a second apex 312 on the outer surface 311. The substrate 1 and the first convex portion 21 are formed of the same polystyrene resin, and the first convex portion 21 can be formed by being pressed by the substrate 1 to be convex thereon. The second convex portion 31 is located above the first convex portion 21 and is connected to the first convex portion 21, and the space of the microstructure 2 is formed by the substrate 1 being pressed and protruded upward to form the first convex portion 21. The remaining space is filled by the second convex portion 31, and the microstructure is a Lenticular lens shape.

Referring to FIG. 5, the convex portion interface 211 of the first convex portion 21 intersects with the line L1 between the lowest points of the first convex portion 21, and the straight line L2 perpendicular to the connecting line L1 and the convex portion interface 211 and the The outer surface 311 of the second convex portion 31 intersects at two points p1 and q1, and the p1q1 line segment is the maximum vertical distance between the outer surface 311 of the second convex portion 31 to the convex portion interface 211 of the first convex portion 21, when p1q1 When the line segment moves to both sides of the first convex portion 21, the vertical distance gradually becomes smaller, that is, the p1q1 line segment>p2q2 line segment>p3q3 line segment or the p1q1 line segment>p4q4 line segment>p5q5 line segment, wherein the minimum vertical distance H (H=p3q3 line segment= When the p5q5 line segment is less than 5 μm, it helps to fill the cavity 511 with the second resin material. In the present embodiment, the minimum vertical distance H between the outer surface 311 of the second convex portion 31 to the convex portion interface 211 of the first convex portion 21 is less than 1 μm.

Referring to FIG. 6 , the vertical distance between the second vertex 312 on the outer surface 311 of the second convex portion 31 and the lowest point L1 on the two sides of the first convex portion 21 is D1, and the convex portion of the first convex portion 21 is defined. The vertical distance between the first vertex 212 on the interface 211 and the line L1 on the two sides is D2, and the ratio of D2/D1 is 0.32, and the transfer rate is 99.5%.

<Preparation method of light guide plate with microstructure according to the present invention>

The preparation method of the second preferred embodiment of the present invention is substantially the same as the preparation method of the first preferred embodiment described above, except that the first resin forming the substrate 1 of the second preferred embodiment is methacrylate. The resin was obtained, and the thickness of the light guide plate having a microstructure after transfer was 2 mm, and the transfer rate was 99.5%.

<Structure of Light Guide Plate with Microstructure of the Invention>

Referring to FIG. 7, the light guide plate structure prepared by the above-mentioned light guide plate is in the shape of a Lenticular lens, and the ratio of D2'/D1' is 0.21, and the phase is adjacent to the second and second. The convex portion 31 may be independently formed on the corresponding first convex portion 21 below the second convex portion 31, that is, the outer surfaces 311 of the adjacent two second convex portions 31 are not connected to each other.

Referring to Figure 8, the structure of the third preferred embodiment of the present invention is substantially the same as that of the first and second preferred embodiments described above, except that the microstructure 2 is in the shape of a triangular mirror.

In summary, the minimum vertical distance H between the outer surface 311 of the second convex portion 31 and the convex portion interface 211 of the first convex portion 21 is less than 5 μm, and the first convex portion 21 and the second convex portion are matched. The portion 31 uses resin materials of different fluidity such that the molding die can independently close each of the second convex portions 31, and the high-flow photosensitive resin material forming the second convex portion 31 is sufficiently filled deep into the cavity 511, Not only is the formed microstructure 2 closer to the predetermined pattern, but the desired optical properties are obtained, and the cost of producing the optical sheet can also be reduced.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

1‧‧‧Substrate

2‧‧‧Microstructure

21‧‧‧First convex

211‧‧‧ convex interface

212‧‧‧ first vertex

31‧‧‧second convex

311‧‧‧ outer surface

312‧‧‧ second vertex

5‧‧‧Molding device

51‧‧‧Molding die

511‧‧‧ cavity

512‧‧‧Transfer microstructure

53‧‧‧Lighting unit

6‧‧‧ UV curing resin raw materials

L1‧‧‧ connection

L2‧‧‧ Straight line

D1, D2, D1', D2'‧‧‧ vertical distance

H‧‧‧Minimum vertical distance

1 is a perspective view showing a conventional optical plate; FIG. 2 is a schematic cross-sectional view showing the first preferred embodiment of the present invention for molding a microstructure through a die; FIG. 3 is similar to FIG. FIG. 4 is a perspective view showing the first preferred embodiment of the present invention having a plurality of semi-circular mirror microstructures; FIG. 5 is a view of FIG. A partially enlarged view showing a detailed view of the microstructure of the first preferred embodiment; FIG. 6 is a schematic cross-sectional view showing a first preferred embodiment of the present invention; and FIG. 7 is a view similar to FIG. A second preferred embodiment; and FIG. 8 is a schematic cross-sectional view showing a microstructure of a triangular mirror according to a third preferred embodiment of the present invention.

1. . . Substrate

2. . . microstructure

twenty one. . . First convex

211. . . Convex interface

212. . . First vertex

31. . . Second convex

311. . . The outer surface

312. . . Second vertex

Claims (10)

A microstructured light diffusing plate comprising: a substrate formed of a first resin material comprising a thermoplastic resin; and a plurality of microstructures on the substrate, the microstructure having a height between 50 and 1000 μm, The distance between the highest points of the microstructure is between 50 and 700 μm. Each microstructure includes a first protrusion formed on the substrate, and a direction away from the substrate is connected to the first protrusion. a second convex portion, the first convex portion is also formed by the first resin material, and has a convex portion interface formed by the connecting surface of the first convex portion and the second convex portion, and a position on the convex portion interface a first apex, the second protrusion being formed of a second resin material including a photosensitive resin, and having an outer surface spaced apart from the convex portion interface of the first convex portion, and one on the outer surface a second apex; and a light diffusing agent added to the first resin material and/or the second resin material; defining a second apex of the second convex portion to a line connecting the lowest points of the first convex portion The vertical distance is D1, and the first vertex of the first convex portion is two The vertical distance between the line connecting the lowest point of the side is D2, D2/D1 is between 0.1 and 0.9, and the minimum vertical distance between the outer surface of the second convex portion and the convex portion interface of the first convex portion is less than 5 μm. According to the micro-structured light diffusing plate of claim 1, the light diffusing plate has a thickness of 0.3 to 3 mm. A light-diffusing sheet having a microstructure according to claim 1, wherein the photosensitive resin material is an ultraviolet light curing resin. The microstructured light diffusing plate according to claim 1, wherein D2/D1 is greater than 0.32 to 0.9. The microstructured light diffusing plate according to claim 1, wherein the shape of the second convex portion is selected from the group consisting of a prism lens, a Lenticular lens, and a phenanthrene lens. Fresnel lens. A microstructured light guide plate comprising: a substrate formed of a first resin material including a thermoplastic resin; and a plurality of microstructures on the substrate, the microstructure height being between 50 and 1000 μm, and The distance between the highest points of the microstructure is between 50 and 700 μm, and each microstructure includes a first protrusion formed on the substrate, and a second protrusion connected to the first protrusion away from the substrate. The first convex portion is also formed by the first resin material, and has a convex portion interface formed by the connecting surface of the first convex portion and the second convex portion, and a first portion at the interface of the convex portion a second protrusion formed by a second resin material including a photosensitive resin, and having an outer surface spaced apart from the convex portion interface of the first convex portion, and a second apex on the outer surface And a light diffusing agent added to the first resin material and/or the second resin material; defining a second vertex of the second convex portion to the lowest side of the first convex portion The vertical distance between the points is D1', and the vertical distance between the first vertex of the first convex portion and the lowest point on both sides is D2', and D2'/D1' is between 0.1 and 0.7. The minimum vertical distance between the outer surface of the second convex portion and the convex portion interface of the first convex portion is less than 5 μm. The light guide plate having a microstructure according to claim 6, wherein the light guide plate has a thickness of 0.3 to 8 mm. The light guide plate having a microstructure according to claim 6, wherein the photosensitive resin material is an ultraviolet light curing resin. The light guide plate having a microstructure according to claim 6, wherein the shape of the second convex portion is selected from the group consisting of a prism lens, a Lenticular lens, and a Fresnel lens. Fresnel lens. The micro-structured light guide plate according to claim 6, wherein the thermoplastic resin material is selected from the group consisting of: (meth) acrylate resin, polystyrene resin, polycarbonate resin, and methacrylic acid Ester-styrene copolymer, acrylonitrile-styrene copolymer, polyethylene terephthalate.