Display device and light diffuse optical film thereof

Abstract

A light diffusion optical film includes a substrate, a core layer and a light diffusion structure. The core layer is formed on the substrate and has a setting surface. A first direction and a second direction orthogonal to each other are defined on the setting surface. The light diffusion structure is formed on the setting surface of the core layer. The light diffusion structure is a union of a plurality of microstructure monomers extending along a first direction and a second direction. Each microstructure monomer includes a first surface and a second surface arranged opposite to each other. The first surface intersects with the setting plane at a first boundary line, the second surface intersects with the setting plane at a second boundary line, and the first surface and the second surface intersect at an edge line. The first boundary line is a straight line or a first curve, the second boundary line is a straight line or a second curve, and the edge line is a straight line or a third curve.

Description

Technical Field

[0001] This invention relates to the technical field of optical films, and more particularly to a light-diffusing optical film. Prior Technology

[0002] Existing liquid crystal display (LCD) devices include a backlight module, a liquid crystal display panel, and a polarizer. The backlight module generates an illumination beam, which passes through the liquid crystal display panel to produce an image. When the unpolarized illumination beam passes through the polarizer, light rays with polarization parallel to the polarizer can pass through to form a polarized beam, while light rays with polarization perpendicular to the polarizer are blocked. When the polarized beam passes through the liquid crystal display panel, the orientation of the liquid crystal molecules creates an illumination or lack of illumination effect at each pixel.

[0003] Because backlights randomize the polarization of light, they reduce the amount of light available to illuminate the liquid crystal display module. Therefore, a technique for maximizing the transmission of polarized light and minimizing the blocking of polarized light involves placing a reflective polarizer between a backlight and an LC panel, allowing at least a portion of the blocked polarized light to be recycled. Existing reflective polarizers mainly consist of a polyester substrate, a core layer disposed on the polyester substrate, and light-diffusing microstructures disposed on the core layer. Existing light-diffusing microstructures form a roughened structure on the surface of the core layer, for example, by attaching particles of different diameters to the surface of the core layer to form a roughened surface structure, or by embossing with a mold to form a roughened surface structure.

[0004] However, the existing light-diffusing microstructures have surface roughening structures composed of tiny scattering particles of different sizes that are randomly and densely distributed, or hemispherical or irregular rough structures. Because these structures are of different sizes, they diffuse light at different angles and reduce light transmittance, thus reducing the brightness of the front of the display. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide a light-diffusing optical film, comprising a substrate, a core layer, and a light-diffusing structure. The core layer is formed on the substrate and generates an optical effect on a light beam incident on the light-diffusing optical film. The core layer has a disposed surface, which is the other side of the core layer adjacent to the substrate, defining an intersecting first direction and a second direction on the disposed surface. The light-diffusing structure includes a microstructure layer formed on the disposed surface of the core layer, and the light-diffusing structure causes the light beam to diffuse. The light-diffusing structure is a set of a plurality of microstructure units extending along the first direction and along the second direction. Each microstructure unit includes a first surface and a second surface disposed opposite to each other. The first surface intersects the disposed surface at a first boundary line, and the second surface intersects the disposed surface at a second boundary line. The first surface and the second surface intersect to form a connecting structure. The first boundary line is a straight line or a first curve, the second boundary line is a straight line or a second curve, and the connecting structure is an edge or an arcuate surface, wherein the edge is a straight line or a third curve.

[0006] In another embodiment, the first curve is a first wavy line, which has a plurality of peaks and a plurality of troughs arranged alternately along a first direction or a second direction.

[0007] In another embodiment, the second curve is a second wavy line having a plurality of peaks and a plurality of troughs arranged alternately along a first direction or a second direction.

[0008] In another embodiment, the third curve is a third wavy line, which has a plurality of peaks and a plurality of troughs arranged alternately along a first direction or a second direction.

[0009] In another embodiment, the first boundary line is a first wavy line and the second boundary line is a second wavy line, and the peaks and troughs of the first wavy line correspond to the peaks and troughs of the second wavy line.

[0010] In another embodiment, the first boundary line is a first wavy line and the second boundary line is a second wavy line, and the peaks and troughs of the first wavy line of one microstructure unit correspond to the peaks and troughs of the first wavy line of another adjacent microstructure unit.

[0011] In another embodiment, the edge is a third wavy line, and the peaks and troughs of the third wavy line correspond to the peaks and troughs of the first wavy line.

[0012] In another embodiment, the first boundary line is a straight line, the second boundary line is a straight line, the edge line is a third wavy line, and the peaks and troughs of the third wavy line are staggered along a third direction, which is perpendicular to the first and second directions.

[0013] In another embodiment, the light diffusion structure includes a plurality of first ridges extending along a first direction and a plurality of second ridges extending along a second direction, wherein at least one first ridge is continuous and at least one second ridge is discontinuous.

[0014] In another embodiment, the light diffusion structure includes a plurality of recesses, each recess being located between two adjacent first ridges and two adjacent second ridges.

[0015] In another embodiment, the bottom of each recess is a cusp, a straight line, a curve, a plane, or a conical surface.

[0016] In another embodiment, the first direction and the second direction intersect at an angle of 45 to 135 degrees.

[0017] In another embodiment, the light diffusion structure further includes a base layer, a microstructure layer formed on a second substrate, and the second substrate formed on a core layer.

[0018] In another embodiment, the radius of curvature of the vertical section of the arcuate surface in the first or second direction is 0.2 micrometers to 30 micrometers.

[0019] This invention provides a display device comprising a backlight module, the aforementioned light-diffusing optical film, and a liquid crystal display panel. The backlight module emits an unpolarized light beam. The unpolarized light beam passes through the core layer of the light-diffusing optical film to form a polarized light beam, and the light-diffusing structure diffuses the polarized light beam to form a two-dimensional illumination beam. The two-dimensional illumination beam passes through the liquid crystal display panel to form an image beam.

[0020] The light-diffusing structure of the light-diffusing optical film of the present invention is formed by assembling multiple microstructure units extending along mutually orthogonal first and second directions. The first boundary line, second boundary line, and ridge line of the microstructure unit can be set as straight lines or curves, and the curves can be periodic or non-periodic wavy lines. In this way, when multiple microstructure units of different shapes and arrangements are combined with each other, a structure in which ridge lines and recesses are alternately arranged can be produced. When the illumination beam passes through the microstructure unit, it can have a substantially the same scattering angle, achieving a uniform light diffusion effect. Simple Explanation of the Diagram

[0021] Figure 1 is a perspective view of an embodiment of the diffusion-type optical film of the present invention. Figure 2 is a perspective view of an embodiment of the light diffusion structure of the diffusion-type optical film of the present invention. Figure 3 is a top view of Figure 2. Figure 4 is a cross-sectional view of an embodiment of the diffusion-type optical film of the present invention. Figure 5 is a cross-sectional view of another embodiment of the diffusion-type optical film of the present invention. Figure 6 is a cross-sectional view of yet another embodiment of the diffusion-type optical film of the present invention. Figure 7 is a three-dimensional view of the configuration of multiple microstructure monomers of the light diffusion structure in Figure 2, which extend along the first and second directions. Figure 8 is a top view of Figure 7. Figure 9 is a top view of the first embodiment of the microstructure monomer of the present invention. Figure 10 is a top view of a second embodiment of the microstructure monomer of the present invention. Figure 11 is a top view of a third embodiment of the microstructure monomer of the present invention. Figure 12 is a top view of the fourth embodiment of the microstructure monomer of the present invention. Implementation

[0022] Please refer to Figure 1, which illustrates an embodiment of the light diffusion structure of the diffusion-type optical film of the present invention. The diffusion-type optical film 1 of this embodiment includes a substrate 10, a core layer 20, and a light diffusion structure 30. The substrate 10 may be a polymer substrate. The core layer 20 is formed on the substrate 10, and the core layer 20 generates an optical effect on the incident light beam of the diffusion-type optical film 1. This optical effect may, for example, allow an unpolarized light beam to pass through the core layer 20, resulting in a beam with a parallel polarization direction passing through to form polarized light.

[0023] The core layer 20 has two sides, one of which is adjacent to the substrate 10, and the other side is defined as the setting surface 21. A first direction L1 and a second direction L2 are defined intersecting on the setting surface 21. In this embodiment, the first direction L1 and the second direction L2 are orthogonal, but the invention is not limited thereto; the first direction L1 and the second direction L2 can also intersect at an angle between 45 degrees and 135 degrees. A light diffusion structure 30 is formed on the setting surface 21 of the core layer 20, and the light diffusion structure 30 diffuses the light beam. The refractive index of the light diffusion structure 30 is 1.45 to 1.90, preferably 1.55.

[0024] Please refer to Figures 2, 3, and 4, which illustrate an embodiment of the light diffusion structure of the diffusion-type optical film of the present invention. The light diffusion structure 30 of this embodiment includes a microstructure layer 31, which includes a plurality of ridges 30a and a plurality of recesses 30b. The ridges 30a are generally formed along a first direction L1 and a second direction L2. Two adjacent first ridges 30a1 extending along the first direction L1 intersect with two adjacent second ridges 30a2 extending along the second direction L2, forming a recess 30b between the two adjacent first ridges 30a1 and the two adjacent second ridges 30a2. Each recess 30b includes two inclined surfaces 30b1 extending obliquely from the two adjacent first ridges 30a1 and two inclined surfaces 30b2 extending obliquely from the two adjacent second ridges 30a2. Both inclined surfaces 30b1 and 30b2 are inclined relative to the surface 21, and can be planar or curved.

[0025] Due to the shape, height, and extension of two adjacent first ridges 30a1 and two adjacent second ridges 30a2, the two inclined surfaces 30b1 and 30b2 intersect and connect at the bottom of the recess 30b. When both inclined surfaces 30b1 and 30b2 are planar, the bottom of the recess 30b is formed as a cusp, a straight line, or a plane. When inclined surfaces 30b1 and / or 30b2 are curved surfaces, the bottom of the recess 30b is formed as a curve or a conical surface.

[0026] Furthermore, as shown in Figure 3, the heights of the first ridge 30a1 and the second ridge 30a2 are the same in region A, for example, so both the first ridge 30a1 and the second ridge 30a2 are continuous straight lines or curves. In region B, the heights of the first ridge 30a1 and the second ridge 30a2 are different, with the height of the second ridge 30a2 being less than the height of the first ridge 30a1. This makes the first ridge 30a1 a continuous straight line or curve, while the second ridge 30a2 forms a discontinuous straight line or curve.

[0027] Please refer to Figure 5, which illustrates another embodiment of the diffusion-type optical film of the present invention. This embodiment has some of the same structure as the previous embodiment, therefore the same elements are given the same reference numerals and their descriptions are omitted. The difference between this embodiment and the previous embodiment is that the light diffusion structure 30 in this embodiment further includes a second substrate 32. The microstructure layer 31 in this embodiment is formed on the second substrate 32, and the second substrate 32 is formed on the core layer 20. The material of the second substrate 32 can be the same as or a different material from the material of the substrate 10.

[0028] Please refer to Figure 6, which illustrates another embodiment of the diffusion-type optical film of the present invention. This embodiment has some of the same structure as the previous embodiment, therefore the same elements are given the same reference numerals and their descriptions are omitted. The difference between this embodiment and the previous embodiment is that an arc-shaped surface 33 is formed at the junction of the two inclined surfaces 30b1 or the two inclined surfaces 30b2 in this embodiment. The arc-shaped surface 33 extends along the first direction L1 or the second direction L2, and the edge of the vertical section of the arc-shaped surface 33 forms an arc, the radius of curvature of which is 0.2 micrometers to 30 micrometers.

[0029] Please refer to Figures 7 and 8, which illustrate a plurality of microstructure units arranged along the first direction L1 and the second direction L2 of the light diffusion structure 30. In this embodiment, the light diffusion structure 30 is a set of multiple microstructure units 31 and multiple microstructure units 32 extending along the first direction L1. The multiple microstructure units 31 extending along the first direction L1 are arranged adjacent to each other in pairs, and the multiple microstructure units 32 extending along the second direction L2 are also arranged adjacent to each other in pairs.

[0030] Please refer to Figures 9, 10, 11, and 12, which respectively illustrate the first, second, third, and fourth embodiments of the microstructure monomer of the present invention. Since microstructure monomer 31 and microstructure monomer 32 have the same structure and shape, except that microstructure monomer 31 extends along the first direction L1 and microstructure monomer 32 extends along the second direction L2, the following description uses microstructure monomer 31 as an example. For simplicity, the same reference numerals are used for the same components.

[0031] As shown in Figure 9, the microstructure unit 31 includes a first surface 311 and a second surface 312 disposed opposite to each other. The first surface 311 intersects the disposed surface 21 at a first boundary line 313, and the second surface 312 intersects the disposed surface 21 at a second boundary line 314. The first surface 311 and the second surface 312 intersect at an edge line 315 (or form an arc-shaped surface). In this embodiment, both the first surface 311 and the second surface 312 are planar, therefore the first boundary line 313, the second boundary line 314, and the edge line 315 are all straight lines.

[0032] As shown in Figure 10, the first surface 311 and the second surface 312 of the microstructure monomer 31 are both curved surfaces, such that the first boundary line 313 is a first curve and the second boundary line 314 is a second curve. The first curve is a first wavy line with a plurality of staggered peaks and troughs. The second curve is a second wavy line with a plurality of staggered peaks and troughs. The peaks and troughs of the first wavy line correspond to those of the second wavy line. The edge 315 is a third curve, and the third curve is a third wavy line. The peaks and troughs of the third wavy line correspond to those of the first wavy line. In this embodiment, the first, second, and third wavy lines form peaks and troughs along the second direction L2.

[0033] As shown in Figure 11, the first surface 311 and the second surface 312 of the microstructure unit 31 are both curved surfaces, making the first boundary line 313 a first curve, the second boundary line 314 a second curve, and the edge line 315 a third curve. The first curve is a first wavy line, the second curve is a second wavy line, and the third curve is a third wavy line. The peaks and troughs of the first, second, and third wavy lines correspond to each other, and the first, second, and third wavy lines form peaks and troughs along the second direction L2. However, the peaks of the first, second, and third wavy lines of the microstructure unit 31 in Figure 8 correspond to the troughs of the first, second, and third wavy lines of the microstructure unit 31 in Figure 7, and the troughs of the first, second, and third wavy lines of the microstructure unit 31 in Figure 8 correspond to the peaks of the first, second, and third wavy lines of the microstructure unit 31 in Figure 7.

[0034] As shown in Figure 12, the first boundary line 313 is a straight line, the second boundary line 314 is a straight line, and the edge line 315 is a third curve, which is a third wavy line. The third wavy line has peaks and troughs at staggered positions. In this embodiment, the third wavy line forms peaks and troughs along a third direction L3. The third direction L3 is orthogonal to both the first direction L1 and the second direction L2, that is, the third direction L3 is perpendicular to the setting surface 21. Therefore, the peaks and troughs of the third wavy line cause the edge line 315 to have different heights relative to the setting surface 21 at different positions. In another embodiment, the first boundary line 313 and the second boundary line 314 can also be straight lines.

[0035] By arranging and combining the various shapes of microstructure monomers 31 as shown in Figures 9, 10, 11, and 12, microstructure monomers 31 extending in the first direction L1 can be obtained. Similarly, by arranging and combining the various shapes of microstructure monomers 32, microstructure monomers 32 extending in the second direction L2 can be obtained. Multiple microstructure monomers 31 and 32 are combined to form a light diffusion structure 30. Thus, various shapes of microstructure monomers 31 and 32 can be combined according to different needs to form different light diffusion characteristics at different positions. For example, the distance between the edges 315 of two adjacent microstructure monomers 31 can be 20 micrometers to 80 micrometers. The height of the edges 315 from the surface 21 can be 10 micrometers to 40 micrometers.

[0036] The light-diffusing structure of the light-diffusing optical film of the present invention is formed by assembling multiple microstructure units extending along mutually orthogonal first and second directions. The first boundary line, second boundary line, and ridge line of the microstructure unit can be set as straight lines or curves, and the curves can be periodic or non-periodic wavy lines. In this way, when multiple microstructure units of different shapes and arrangements are combined with each other, a structure in which ridge lines and recesses are alternately arranged can be produced. When the illumination beam passes through the microstructure unit, it can have a substantially the same scattering angle, achieving a uniform light diffusion effect.

[0037] The light-diffusing optical film of the present invention can be applied to a display device, which includes a backlight module, the aforementioned light-diffusing optical film, and a liquid crystal display panel. The backlight module emits an unpolarized light beam, which passes through the core layer of the light-diffusing optical film to form a polarized light beam. The light-diffusing structure of the light-diffusing optical film further diffuses the polarized light beam to form a two-dimensional illumination beam. The polarized two-dimensional illumination beam passes through the liquid crystal display panel to form an image beam.

[0038] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. Any simple equivalent changes and modifications made in accordance with the claims and description of the present invention are still within the scope of the patent. Furthermore, no embodiment or claim of the present invention needs to achieve all the objectives, advantages, or features disclosed in the present invention. In addition, the abstract and headings are merely for assisting in patent document searches and are not intended to limit the scope of the present invention. Furthermore, the terms "first," "second," etc., used in this specification or claims are only used to name elements or distinguish different embodiments or scopes, and are not intended to limit the upper or lower limit of the number of elements.

[0039] 1: Diffuse type optical film 10: Substrate 20: Core Layer 21: Set Surface 30: Light diffusion structure 31: Microstructure layer 32: Second substrate 33: Curved surface 30a: Edge line 30a1: First edge line 30a2: Second edge line 30b: concave part 30b1: Inclined plane 30b2: Incline 31: Microstructure monomer 32: Microstructure monomers 311: First Surface 312: Second Surface 313: First Boundary Line 314: Second Boundary Line 315: Edge L1: First direction L2: Second direction L3: Third-party

Claims

1. A light-diffusing optical film, comprising: One substrate; A core layer, formed on the substrate, provides an optical effect for a light beam incident on the light-diffusing optical film. The core layer has a surface adjacent to the substrate, defining a first direction and a second direction intersecting on the surface. A light-diffusing structure, formed on the surface of the core layer, diffuses the light beam. The light-diffusing structure includes a microstructure layer, which is a collection of multiple microstructure units extending along the first direction and the second direction. Each microstructure unit includes a first surface and a second surface disposed opposite to each other. The first surface intersects the surface at a first boundary line, and the second surface intersects the surface at a second boundary line. The first surface and the second surface intersect to form a connecting structure. The first boundary line is a straight line or a first curve, the second boundary line is a straight line or a second curve, and the connecting structure is an edge or an arcuate surface. The edge is a straight line or a third curve.

2. The light-diffusing optical film as claimed in claim 1, wherein the first curve is a first wavy line having a plurality of peaks and a plurality of troughs arranged alternately along the first direction or the second direction.

3. The light-diffusing optical film as claimed in claim 2, wherein the second curve is a second wavy line having a plurality of peaks and a plurality of troughs arranged alternately along the first direction or the second direction.

4. The light-diffusing optical film as claimed in claim 3, wherein the third curve is a third wavy line having a plurality of peaks and a plurality of troughs arranged alternately along the first direction or the second direction.

5. The light-diffusing optical film as claimed in claim 4, wherein the first boundary line is the first wavy line and the second boundary line is the second wavy line, and the peaks and troughs of the first wavy line correspond to the peaks and troughs of the second wavy line.

6. The light-diffusing optical film as claimed in claim 4, wherein the first boundary line is a first wavy line and the second boundary line is the second wavy line, and the peak and trough of the first wavy line of one microstructure unit correspond to the peak and trough of the first wavy line of the adjacent microstructure unit.

7. The light-diffusing optical film as claimed in claim 4, wherein the first boundary line is a first wavy line and the second boundary line is the second wavy line, and the peak and trough of the first wavy line of one microstructure unit correspond to the trough and peak of the first wavy line of the adjacent microstructure unit.

8. The light-diffusing optical film as claimed in claim 5, 6 or 7, wherein the ridge is the third wavy line, and the peaks and troughs of the third wavy line correspond to the peaks and troughs of the first wavy line.

9. The light-diffusing optical film as claimed in claim 4, wherein the first boundary line is a straight line, the second boundary line is a straight line, the edge line is the third wavy line, and the third wavy line is formed by staggered peaks and troughs along a third direction, the third direction being perpendicular to the first direction and the second direction.

10. The light-diffusing optical film as claimed in claim 1, wherein the light-diffusing structure includes a plurality of first ridges extending along the first direction and a plurality of second ridges extending along the second direction, wherein at least one of the first ridges is continuous and at least one of the second ridges is discontinuous.

11. The light-diffusing optical film as claimed in claim 10, wherein the light-diffusing structure includes a plurality of recesses, each recess being located between two adjacent first ridges and two adjacent second ridges.

12. The light-diffusing optical film as claimed in claim 11, wherein the bottom of each recess is a cusp, a straight line, a curve, a plane, or a conical surface.

13. The light-diffusing optical film as claimed in claim 1, wherein the first direction and the second direction intersect at an angle of 45 degrees to 135 degrees.

14. The light-diffusing optical film as claimed in claim 1, wherein the light-diffusing structure further includes a second substrate, the microstructure layer is formed on the second substrate, and the second substrate is formed on the core layer.

15. The light-diffusing optical film as claimed in claim 1, wherein the radius of curvature of the arcuate surface in the first direction or the second direction is from 0.2 micrometers to 30 micrometers.

16. A display device comprising: A backlight module that emits an unpolarized light beam; a light-diffusing optical film as described in any one of claims 1 to 15, wherein the unpolarized light beam passes through the core layer of the light-diffusing optical film to form a polarized light beam, and the light-diffusing structure diffuses the polarized light beam to form a two-dimensional illumination beam; and a liquid crystal display panel, wherein the two-dimensional illumination beam passes through the liquid crystal display panel to form an image beam.

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