Optical film, backlight module and display device

Abstract

An optical film comprises a plate body and a plurality of column bodies. The plate body has a first surface and a second surface opposite to each other. The column body is arranged on the first surface. Each cylinder has a base portion and a convex portion. The convex top part has a top surface, and the base part has a first inclined surface and a second inclined surface. The top surface is provided with a first side line and a second side line which are opposite. The first slope connects the first side line and the first surface, and the second slope connects the second side line and the first surface. On a cross section vertical to the first side line, the convex top part is asymmetrical to pass through and is vertical to a middle line of the first surface; or the convex top part is provided with a side surface connected with the first inclined surface, and the slope of the side surface relative to the first surface is different from that of the first inclined surface relative to the first surface. The optical film provided by the utility model can improve the durability and maintain the effect of guiding light beams to be close to forward light emission. The utility model further provides a backlight module with the optical film and a display device with the backlight module.

Description

Technical Field

[0001] The utility model relates to an optical element, in particular to an optical film, a backlight module having the above optical film, and a display device having the above backlight module. Background Art

[0002] The structure of a liquid crystal display device mainly includes components such as a backlight module and a display panel. Among them, the backlight module is used to provide the surface light source required by the display panel. According to the different directions of the light source, the backlight module can be further divided into a side-light type backlight module and a direct-lit type backlight module. Generally speaking, the side-light type backlight module has the advantage of being thin, and the direct-lit type backlight module is beneficial to achieving the function of local dimming.

[0003] Most of the known backlight modules are provided with multiple prism sheets to guide the light beam to approach the forward light output, and thereby improve the light output brightness of the backlight module. However, the prism columns of the prism sheet have sharp corners, resulting in the prism sheet being easily worn. For example, the sharp corners of the prism sheet will come into contact with the display panel. In this way, not only the sharp corners of the prism sheet are worn and deformed by the display panel, resulting in a decrease in the light output brightness of the backlight module, but also the display panel will be scratched by the prism sheet, causing the image quality and durability of the liquid crystal display device to deteriorate. Some known prism sheets reduce scratches and wear by changing the material, but this also results in a decrease in the brightness gain of the backlight module, thereby affecting the image quality of the liquid crystal display device.

[0004] The "Background Art" paragraph is only used to help understand the content of the present utility model. Therefore, the content disclosed in the "Background Art" paragraph may include some known technologies that are not known to those skilled in the art of the relevant technical field. The content disclosed in the "Background Art" paragraph does not represent that the content or the problems to be solved by one or more embodiments of the present utility model have been known or recognized by those skilled in the art before the application of the present utility model. Summary of the Utility Model

[0005] The present utility model provides an optical film to improve durability and maintain the effect of guiding the light beam to approach the forward light output.

[0006] The present utility model provides a backlight module to improve durability and maintain the light output brightness.

[0007] The present utility model provides a display device to improve durability and maintain the image quality.

[0008] Other objects and advantages of the present utility model can be further understood from the technical features disclosed in the present utility model.

[0009] To achieve one or part or all of the above purposes or other purposes, an optical film according to an embodiment of the present invention includes a plate body and a plurality of columns. The plate body has opposite first and second surfaces. The columns are disposed on the first surface. Each column has a base portion and a convex top portion. The convex top portion has a top surface, and the base portion has a first inclined surface and a second inclined surface. The top surface has opposite first and second side lines. The first inclined surface connects the first side line and the first surface, and the second inclined surface connects the second side line and the first surface. In a cross-section perpendicular to the first side line, the contour of the base portion is trapezoidal, and the contour of the top surface is two straight line segments with different lengths, a semi-circular arc, a quadratic Bezier curve, or a parabola.

[0010] To achieve one or part or all of the above purposes or other purposes, a backlight module according to an embodiment of the present invention includes a light-emitting element, a light guide plate, and the above-mentioned optical film. The light guide plate has an incident light surface and an outgoing light surface connected to each other, and the incident light surface faces the light-emitting element. The optical film is disposed opposite to the outgoing light surface.

[0011] To achieve one or part or all of the above purposes or other purposes, a display device according to an embodiment of the present invention includes the above-mentioned backlight module and a display panel. The display panel is disposed opposite to the backlight module.

[0012] The optical film of the present invention uses columns with convex top portions, wherein the convex top portions can significantly reduce the degree of mutual abrasion with other optical elements compared to known sharp corners, and the first inclined surface and the second inclined surface of the base portion can guide the light beam to approach forward light emission. In addition, because the contour of the top surface of the convex top portion is two straight line segments with different lengths, a semi-circular arc, a quadratic Bezier curve, or a parabola, the convex top portion can also guide a small part of the light beam to deviate slightly from forward light emission, thereby increasing the light guiding characteristics of the optical film. Therefore, the optical film of the present invention can not only improve the durability and maintain the effect of guiding the light beam to approach forward light emission, but also provide more diverse light guiding characteristics. The backlight module of the present invention uses the above-mentioned optical film, so it can improve the durability and maintain the outgoing light brightness. The display device of the present invention uses the above-mentioned backlight module, so it can improve the durability and maintain the image quality.

[0013] To make the above and other purposes, features, and advantages of the present invention more obvious and understandable, the following specific preferred embodiments are given, and detailed descriptions are provided in conjunction with the accompanying drawings as follows. Description of the Drawings

[0014] Figure 1 is a schematic diagram of an optical film according to an embodiment of the present invention.

[0015] Figure 2 is Figure 1 a cross-sectional schematic diagram of the optical film along the V1-V1 section line.

[0016] Figure 3 is Figure 2 A partially enlarged schematic view of the optical film.

[0017] Figure 4 is a schematic view of the optical film of another embodiment of the present utility model.

[0018] Figure 5 is Figure 4 A partial sectional view of the optical film along the V2-V2 section line.

[0019] Figure 6 is a schematic view of the optical film of another embodiment of the present utility model.

[0020] Figure 7 is Figure 6 A partial sectional view of the optical film along the V3-V3 section line.

[0021] Figure 8 is Figure 7 A partially enlarged schematic view of the optical film.

[0022] Figure 9 is a schematic view of the optical film of another embodiment of the present utility model.

[0023] Figure 10 is Figure 9 A partial sectional view of the optical film along the V4-V4 section line.

[0024] Figure 11 is a schematic view of various embodiments of the optical film of another embodiment of the present utility model.

[0025] Figure 12 is a sectional view of the optical film of another embodiment of the present utility model.

[0026] Figure 13 is a sectional view of the optical film of another embodiment of the present utility model.

[0027] Figure 14 is a side view of the optical film of another embodiment of the present utility model.

[0028] Figure 15 is a top view of the optical film of another embodiment of the present utility model.

[0029] Figure 16 is a schematic view of the optical film of another embodiment of the present utility model.

[0030] Figure 17 is a schematic view of a backlight module of an embodiment of the present utility model.

[0031] Figure 18Schematic diagram of a display device according to an embodiment of the present utility model.

[0032] Explanation of reference numerals:

[0033] 10, 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h, 10i: Optical film

[0034] 12, 12a, 12b, 12c, 12d, 12e, 12g, 12h, 12i: Cylinder

[0035] 20: Backlight module

[0036] 21: Light-emitting element

[0037] 22: Light guide plate

[0038] 23: Prismatic sheet

[0039] 24: Diffusion sheet

[0040] 30: Display device

[0041] 31: Display panel

[0042] 121: Base

[0043] 122, 122a, 122b, 122c, 122d, 122e, 122g, 122h: Convex top

[0044] 1211: First inclined plane

[0045] 1212: Second inclined plane

[0046] A, A0, A1: Included angle

[0047] B: Quadratic Bezier curve

[0048] BA1: First base angle

[0049] BA2: Second base angle

[0050] C, Ca, Cb, Cc: Cross-section

[0051] CL: Convex curve

[0052] D1, D2, D1’, D2’: Distance

[0053] DH: Maximum height difference

[0054] DM, DMf: Light diffusion microstructure

[0055] E1: First side line

[0056] E1’, E1”: Edge

[0057] E2, E2g, E2h: Second side line

[0058] EP1: First endpoint

[0059] EP2: Second endpoint

[0060] ES: Light-emitting surface

[0061] ES1, ES2: End face

[0062] FS: Plane

[0063] H: Height

[0064] HC: Semi-cylinder

[0065] IS: Light-incident surface

[0066] L1: Bottom side

[0067] L2: Flat top line

[0068] M: Median line

[0069] MA: Maximum amplitude

[0070] N: Normal direction

[0071] P0, P1, P2: Fixed points

[0072] PA: Parabola

[0073] R1, R2, R2a, R2b, R2c: Contour

[0074] S1: First surface

[0075] S2: Second surface

[0076] S3: Third surface

[0077] S4: Fourth surface

[0078] SL: Straight line segment

[0079] SL1: First straight line segment

[0080] SL2: Second straight line segment

[0081] SS, SSa, SSb, SSc: Side surface

[0082] T: Vertex

[0083] TS, TS1, TS2, TSa, TSb, TSc: Top surface

[0084] W1, W2: Length

[0085] X, Y: Direction

[0086] Z1, Z2: Axial direction. Specific embodiments

[0087] Regarding the foregoing and other technical contents, features and effects of the present utility model, they will be clearly presented in the following detailed description of a preferred embodiment with reference to the accompanying drawings. The directional terms mentioned in the following embodiments, such as: up, down, left, right, front or rear, etc., are only the directions of the reference drawings. Therefore, the directional terms used are for illustration and not for limiting the present utility model.

[0088] The present utility model provides an optical film, including a plate body and a plurality of columns. The plate body has opposite first and second surfaces. The plurality of columns are disposed on the first surface. Each column has a base portion and a convex top portion. The convex top portion has a top surface, the base portion has a first inclined surface and a second inclined surface. The top surface has opposite first and second side lines. The first inclined surface connects the first side line and the first surface, and the second inclined surface connects the second side line and the first surface. In a cross-section perpendicular to the first side line, the contour of the base portion is trapezoidal, and the contour of the top surface is two straight line segments with different lengths, a semi-circular arc, a quadratic Bezier curve or a parabola. Therefore, the optical film proposed by the present utility model can improve the durability and maintain the effect of guiding the light beam to be close to the forward light output. Each embodiment is described as follows.

[0089] Figure 1 It is a schematic diagram of an optical film according to an embodiment of the present utility model. Figure 2 is Figure 1 A cross-sectional view of the optical film along the V1-V1 section line. Figure 3 is Figure 2 A partial enlarged view of the optical film. Please first refer to Figure 1 , Figure 2 and Figure 3 , the optical film 10 includes a plate body 11 and a plurality of columns 12. In this embodiment, five columns 12 are taken as an example, but the present utility model is not limited thereto. The plate body 11 of this embodiment has opposite first and second surfaces S1 and S2. The columns 12 are disposed on the first surface S1. Each column 12 has a base portion 121 and a convex top portion 122. The convex top portion 122 has a top surface TS, and the base portion 121 has a first inclined surface 1211 and a second inclined surface 1212. The top surface TS has opposite first and second side lines E1 and E2. The top surface TS includes, for example, top surfaces TS1 and TS2. The top surface TS1 has the second side line E2, and the top surface TS2 has the first side line E1. The first inclined surface 1211 connects the first side line E1 and the first surface S1, and the second inclined surface 1212 connects the second side line E2 and the first surface S1. Please continue to refer to Figure 3, on the cross-section C perpendicular to the first side line E1, the contour R1 of the base 121 is trapezoidal, and the contour of the convex top 122 is triangular, meaning that the contour R2 of the top surface TS is two straight line segments SL.

[0090] Please refer to Figure 1 and Figure 2 , the first surface S1 of the plate body 11 can be a flat surface. The material of the plate body 11 includes, for example, poly(methyl methacrylate) (PMMA) or polyethyleneterephthalate (PET), but the present invention is not limited thereto.

[0091] In this embodiment, the column 12 and the plate body 11 can be an integral structure, and the material of the column 12 is different from that of the plate body 11. For example, the column 12 can be formed by processes such as cutting or rolling. For example, a photocurable colloid is provided on the plate body 11, and processes such as rolling and curing are performed to form the column 12. The base 121 and the convex top 122 can be an integral structure. The base 121 can be a quadrangular prism, and in this embodiment, a trapezoidal prism is exemplified. Each base 121 can have opposite end faces ES1 and ES2 (shown in Figure 1 ), and the end faces ES1 and ES2 stand on (for example, are substantially perpendicular to) the first surface S1, where the first side line E1 and the second side line E2 of each convex top 122 extend from the end face ES1 to the end face ES2.

[0092] Please refer to Figure 2 and Figure 3, it should be noted that in the known technology, the sharp corners of some prism lenses are changed to rounded corners to improve the wear problem. However, when light exits from the above-mentioned rounded corners, it will diverge significantly, resulting in a significant decrease in the forward luminance, thus deteriorating the luminance gain of the prism lens. However, in this embodiment, the contour R2 of the top surface TS can be two straight line segments SL with different lengths. The two straight line segments SL include a first straight line segment SL1 and a second straight line segment SL2. The first straight line segment SL1 is, for example, the contour of the top surface TS2, and the second straight line segment SL2 can be the contour of the top surface TS1. The angle A0 between the first straight line segment SL1 and the first surface S1 is equal to the angle between the first inclined surface 1211 and the first surface S1 (i.e., the first base angle BA1). The second straight line segment SL2 has opposite first and second end points EP1 and EP2. The first end point EP1 is, for example, connected to the first straight line segment SL1, and the second end point EP2 is, for example, connected to the second inclined surface 1212. The distance D1 from the first end point EP1 to the first surface S1 is greater than the distance D2 from the second end point EP2 to the first surface S1, and there is an angle A between the second straight line segment SL2 and the first surface S1, and the angle A can be greater than 0 degrees and less than or equal to 10 degrees. In other words, the convex top 122 of each column 12, for example, includes a plane (i.e., the top surface TS1) facing away from the first surface S1. Therefore, the convex top 122 can greatly reduce the degree of mutual wear with other optical elements compared with the sharp corners, and can improve the forward luminance compared with the rounded corners, thereby improving the durability and luminance gain of the optical film 10. In addition, because the plane is slightly inclined relative to the first surface S1, the plane can also guide a small part of the light beam to deviate slightly from the forward light output, thereby increasing the light guiding characteristics of the optical film 10. In addition, the plane also has the advantage of being easy to process and form. The first end point EP1 of this embodiment is, for example, the intersection point of the second straight line segment SL2 and the first straight line segment SL1, and the second end point EP2 can be the intersection point of the second straight line segment SL2 and the second side line E2 (labeled in Figure 1 and Figure 2 ).

[0093] Incidentally, in one embodiment, the planes of the respective columns 12 can face different directions to provide different light guiding effects. For example, the plate body 11 can also have opposite third and fourth surfaces S3 and S4, and the first surface S1 and the second surface S2 are located between the third surface S3 and the fourth surface S4. The planes of some of the columns 12 can be slightly oriented towards the third surface S3. Similarly, the planes of another part of the columns 12 can be slightly oriented towards the fourth surface S4.

[0094] From another perspective, please continue to refer to Figure 3, in this embodiment, each column 12 may have a bottom edge L1 and a flat top line L2 on the cross-section C. The bottom edge L1 is located on the first surface S1. The flat top line L2 is parallel to the bottom edge L1, and the flat top line L2 connects the first side line E1 and the second side line E2 (labeled in Figure 1 and Figure 2 ), that is to say, the flat top line L2 is the upper side of the contour R1 of the base portion 121 (i.e., the lower side line of the contour of the convex top portion 122). The length of the bottom edge L1 is W1, and the length of the flat top line L2 is W2, 0.8 ≦ (W1 / W1 + W2) < 1. In this way, the luminance of the light beam emitted from the convex top portion 122, the first inclined surface 1211, and the second inclined surface 1212 can be further increased, and the column 12 also has the advantage of being easy to process. In one embodiment, 15μm ≦ W1 ≦ 65μm, 0.5μm ≦ W2 ≦ 10μm, so that the luminance of the light emitted from each column 12 can be further improved and it can be even easier to process.

[0095] In this embodiment, each column 12 has a first bottom angle BA1 and a second bottom angle BA2. The angles of the first bottom angle BA1 and the second bottom angle BA2 can be greater than or equal to 3 degrees and less than or equal to 65 degrees. In one embodiment, the first bottom angle BA1 can be greater than the included angle A. In addition, the first bottom angle BA1 and the second bottom angle BA2 of this embodiment can be equal to each other. Specifically, the first inclined surface 1211 and the second inclined surface 1212 are inclined relative to the first surface S1, and the first bottom angle BA1 is sandwiched between the first inclined surface 1211 and the first surface S1, and the second bottom angle BA2 is sandwiched between the second inclined surface 1212 and the first surface S1.

[0096] Compared with the prior art, the optical film 10 of this embodiment uses columns 12 with convex top portions 122, in which the convex top portions 122 can significantly reduce the degree of mutual wear with other optical elements compared with the known sharp corners. The first inclined surface 1211 and the second inclined surface 1212 of the base portion 121 can guide the light beam to approach forward light emission. In addition, because the contours R2 of the top surfaces TS1 and TS2 of the convex top portion 122 are two straight line segments SL with different lengths, the convex top portion 122 can also guide a small part of the light beam to deviate slightly from the forward light emission, thereby increasing the light guiding characteristics of the optical film 10. Therefore, the optical film 10 of this embodiment can not only improve the durability and maintain the effect of guiding the light beam to approach forward light emission, but also provide more diverse light guiding characteristics.

[0097] Figure 4 is a schematic diagram of an optical film of another embodiment of the present invention. Figure 5 is Figure 4 a partial cross-sectional schematic diagram of the optical film along the V2 - V2 section line. The structure and advantages of the optical film 10a of this embodiment are similar to those of Figure 1 the embodiment, and only the differences will be described below. Please refer to Figure 4 and Figure 5, the convex top 122a may include a semi-cylinder HC, that is, the contour R2a of the top surface TSa is a semi-circular arc, and the axial direction Z1 of the semi-cylinder HC is parallel to the first side line E1 or the second side line E2. In this embodiment, the axial direction Z1 is, for example, parallel to both the first side line E1 and the second side line E2. The tangents at the two end points of the contour R2a of the top surface TSa are, for example, respectively perpendicular to the first surface S1. In this way, the convex top 122a can not only guide a small part of the light beam to deviate slightly from the forward light output, so as to further enhance the light guiding characteristics of the optical film 10a, but also because the top surface TSa of the convex top 122a is a semi-circular arc surface, it can also diverge the light beam, thereby further improving the light output uniformity of the optical film 10a. In addition, compared with the known sharp corners, the convex top 122a with a semi-circular arc surface can greatly reduce the degree of mutual wear with other optical elements and also has the advantage of being easy to process and form. Incidentally, the top surface TSa can be the circumferential surface of the semi-cylinder HC, and the convex top 122a can be symmetric about the center line M (the center line M is, for example, the symmetry line of the contour R1 of the base 121) in the cross-section Ca, but other embodiments are not limited to this.

[0098] Figure 6 It is a schematic diagram of an optical film according to another embodiment of the present utility model. Figure 7 is Figure 6 The partial cross-sectional schematic diagram of the optical film along the V3-V3 section line. Figure 8 is Figure 7 The partial enlarged schematic diagram of the optical film. The structure and advantages of the optical film 10b in this embodiment are similar to those of Figure 4 the embodiment of Figure 6 and Figure 7 , the contour R2b of the top surface TSb may include a convex curve CL, and the vertex T of the convex curve CL may be misaligned with the center line M (the center line M is, for example, the symmetry line of the contour R1 of the base 121). In other words, the top surface TSb of the convex top 122b can be a convex curved surface, and the convex curve CL is not symmetric about the center line M in the cross-section Cb. In this way, in addition to having the advantages of improving the durability of the optical film 10b, improving the light output uniformity and being easy to process, the convex top 122b can also provide more diverse light guiding effects. Please refer to Figure 7 and Figure 8 , specifically, the contour R2b of the top surface TSb includes a quadratic Bezier curve B, so the convex top 122b also has the advantage of being easy to design. The formula of the quadratic Bezier curve B is as follows:

[0099] Y(t)=(1 - t) 2 *P0 + 2t*(1 - t)*P1 + t 2 *P3, t ∈ [0,1]

[0100] where the positions of the fixed points P0, P1 and P2 are as shown in Figure 8As shown, the fixed points P0 and P1 are, for example, the two end points of the contour R2b of the top surface TSb. The projection point of the fixed point P2 on the flat top line L2 is, for example, located between the projection points of the fixed points P0 and P1 on the flat top line L2, but the present invention is not limited thereto. In one embodiment, the fixed point P2 is not on the median line M, but the present invention is not limited thereto.

[0101] Figure 9 It is a schematic diagram of an optical film of another embodiment of the present invention. Figure 10 is Figure 9 A partial cross-sectional view of the optical film along the V4-V4 section line. The structure and advantages of the optical film 10c of this embodiment are similar to Figure 4 the embodiment of, and only the differences will be described below. Please first refer to Figure 9 and Figure 10 , the contour R2c of the top surface TSc includes a parabola PA. The parabola PA conforms to: H = a*(W2 / 2) 2 , where H is the height of the parabola PA relative to the flat top line L2, a is a constant, and the range of a can include: -48 < a < -0.12. In this way, the convex top 122c can improve the durability of the optical film 10c, improve the light output uniformity, and also has the advantage of being easy to process. It should be noted that the value of a can be determined according to the value of the length W2, so the present invention does not limit this too much. In this embodiment, the parabola PA can be symmetric about the median line M in the cross-section Cc. In one embodiment, the angles between the tangents of the two end points of the contour R2c of the top surface TSc and the first surface are greater than the first base angle BA1, but the present invention is not limited thereto.

[0102] Figure 11 It is a schematic diagram of various embodiments of an optical film of another embodiment of the present invention. The structure and advantages of the optical film 10d of this embodiment are similar to Figure 1 the embodiment of, and only the differences will be described below. Please refer to Figure 11 the embodiment (a), the shapes of the convex tops of at least some of the columns can be different from each other; for example, the shapes of each convex top 122a, 122b, 122c, 122d, and 122e of the optical film 10d are all different from each other, and can also be different from those not shown in Figures 1 to 10The convex tops 122d and 122e are mixed, enabling the optical film 10d to provide more diverse light guiding effects. Specifically, the convex top 122d of the column 12d can be rounded, while the convex top 122e of the column 12e can be pointed. In the embodiment (b), the shapes of the convex tops 122b of the two columns 12b located on the opposite sides of the plate 11 can be the same as each other, and the shapes of the convex tops 122d of the two columns 12d located between the two columns 12b are the same, but the shape of the convex top 122d is different from the shape of the convex top 122b. In the embodiment (c), the shapes of the convex tops 122a and 122b of the columns 12a and 12b located on the opposite sides of the plate 11 can be different from each other, and the shapes of the convex tops 122d of the two columns 12d located between the columns 12a and 12b are the same, and the shape of the convex top 122d is different from the shapes of the convex tops 122a and 122b. In the embodiments (d) and (e), two of the six columns can be the columns 12a, 12b, and 12d, that is, two of the six convex tops can be the convex tops 122a, 122b, and 122d, and the arrangement order of each of the columns 12a, 12b, and 12d is not limited to that shown in the embodiments (d) and (e). It can be understood that each of the embodiments shown in this example is only an example, and the columns 12d and 12e can be replaced by one of the columns 12, 12a, 12b, and 12c, and the present utility model does not limit this further.

[0103] Figure 12 is a cross-sectional schematic view of an optical film according to another embodiment of the present utility model. Figure 13 is a cross-sectional schematic view of an optical film according to another embodiment of the present utility model. Please first refer to Figure 12 , the structure and advantages of the optical film 10e in this embodiment are similar to those of Figure 1 's embodiment, and only the differences will be described below. The optical film 10e, for example, further has a plurality of light diffusion microstructures DM, and the light diffusion microstructures DM are located on the second surface S2 of the plate 11. Therefore, the optical film 10e can diffuse light through the light diffusion microstructures DM, thereby improving the optical quality. In this embodiment, a colloid can be coated on the second surface S2 of the plate 11, and before the colloid is cured, microstructures are embossed with a roller and then cured to generate a plurality of light diffusion microstructures DM having a light diffusion effect. In one embodiment, the plurality of light diffusion microstructures DM can be, for example, Figure 12 the diffusion microstructures shown in the optical film 10e of Figure 13 , or for example, the optical film 10f shown in , the light diffusion microstructure DMf can have a curved surface protruding from the second surface S2. In another embodiment, the light diffusion microstructure can be formed by providing an anti-glare coating on the second surface S2. For example, a colloid having tiny granular spheres is coated on the second surface S2 of the plate 11, and the tiny granular spheres can diffuse light to achieve a light diffusion effect.

[0104] Figure 14 It is a side view schematic diagram of an optical film of another embodiment of the present utility model. The structure and advantages of the optical film 10g in this embodiment are similar to those of Figure 1 the embodiment, and only the differences will be described below. Please refer to Figure 14 , the convex top 122g of each column 12g can be uneven in the normal direction N to provide the function of diffusing light, thereby improving the optical quality of the optical film 10g. It should be noted that Figure 14 only one column 12g is shown to clearly present the characteristics of the column 12g. Specifically, the top surface TS1 may further have an edge E1' opposite to the second side line E2g, and the edge E1' and the second side line E2g may include wavy lines that undulate in the normal direction N, so that the distances D1' and D2' between each column 12g and the first surface S1 are not fixed values, and thus each convex top 122g is uneven in the normal direction N. In one embodiment, the edge E1' and the second side line E2g may include serrated lines that undulate in the normal direction N, so that each convex top 122g is uneven in the normal direction N. In another embodiment, the edge E1' and the second side line E2g may include irregular lines. Incidentally, in one embodiment, the edge E1' and the second side line E2g may have a maximum height difference DH in the normal direction N, and the maximum height difference DH is, for example, less than or equal to 16 μm, but the present utility model does not limit this much.

[0105] Figure 15 It is a top view schematic diagram of an optical film of another embodiment of the present utility model. The structure and advantages of the optical film 10h in this embodiment are similar to those of Figure 1 the embodiment, and only the differences will be described below. Please refer to Figure 15 , the convex top 122h of each column 12h, for example, bends left and right along the first surface S1 to provide the function of diffusing light, thereby improving the optical quality of the optical film 10h. Specifically, the first surface S1 is substantially parallel to the X-Y plane, and the edge E1'' and the second side line E2h may include wavy lines, where the above wavy lines may extend in the Y direction and have undulations in the X direction, so that the convex top 122h bends left and right along the first surface S1. Similarly, in one embodiment, the edge E1'' and the second side line E2h may include serrated lines or irregular lines. In another embodiment, the edge E1'' has a maximum amplitude MA in the X direction, and the maximum amplitude MA is, for example, less than or equal to 16 μm. It can be understood that in one embodiment, the convex top 122h may have both the aforementioned up-and-down undulations and left-and-right bending.

[0106] Figure 16 It is a schematic diagram of an optical film of another embodiment of the present utility model. The structure and advantages of the optical film 10i in this embodiment are similar to those of Figure 1For embodiments, only the differences will be described below. Please first refer to Figure 16 , the columns 12i can be arranged in different directions X and Y. The directions X and Y are parallel to the first surface S1, and the included angle A1 between the directions X and Y can be less than 180°. Further, the columns 12i can be arranged in an array along the directions X and Y that are substantially perpendicular to each other. For example, the optical film 10i can include nine columns 12i, and the nine columns 12i can be arranged in a 3*3 matrix along the directions X and Y. It can be understood that in other embodiments, the number and arrangement of the columns 12i are not limited to Figure 16 as shown.

[0107] Figure 17 is a schematic diagram of a backlight module according to an embodiment of the present invention. Please refer to Figure 17 , the backlight module 20 includes a light-emitting element 21, a light guide plate 22, and an optical film 10. The light guide plate 22 has an incident light surface IS and an outgoing light surface ES connected to each other, and the incident light surface IS faces the light-emitting element 21. The optical film 10 is disposed opposite to the outgoing light surface ES.

[0108] The light-emitting element 21 can include a light-emitting diode (LED). Further, the number of the light-emitting diodes can be multiple, and the emission wavelength can include blue light or white light, but the present invention does not limit this much.

[0109] The material of the light guide plate 22 can include plastic, glass, or other materials suitable for light penetration. For example, in this embodiment, the material of the light guide plate 22 can include polymethyl methacrylate (PMMA), cycloolefin polymer (COP), or polycarbonate (PC). In addition, the light guide plate 22 can be made by hot embossing or injection molding. Incidentally, in one embodiment, the included angle between the incident light surface IS and the axial direction of each column can be greater than or equal to 60 degrees and less than or equal to 90 degrees. In another embodiment, the included angle between the incident light surface IS and the axial direction is, for example, greater than or equal to 0 degrees and less than or equal to 30 degrees.

[0110] The backlight module 20 of this embodiment, for example, further includes a prism sheet 23. The second surface S2 faces the outgoing light surface ES, and the prism sheet 23 is disposed between the second surface S2 and the outgoing light surface ES. Specifically, the axial direction Z2 of the prism columns of the prism sheet 23 can be substantially perpendicular to the axial direction Z1 of the columns, so that the prism sheet 23 and the optical film 10 can respectively reduce the outgoing light divergence angles of the horizontal view angle and the vertical view angle, thereby improving the forward luminance of the backlight module 20.

[0111] Incidentally, the backlight module 20 may further include a diffusion sheet 24, which is disposed between the prism sheet 23 and the light-emitting surface ES. Thus, the light emitted from the light-emitting surface ES can first pass through the diffusion sheet 24 and then enter the prism sheet 23 and the optical film 10, thereby improving the optical quality of the backlight module 20.

[0112] Compared with the prior art, the backlight module 20 of this embodiment uses the optical film 10, so the durability can be improved and the light emission luminance can be maintained. In other embodiments, the backlight module 20 may use the optical films 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h or 10i.

[0113] Figure 18 It is a schematic diagram of a display device according to an embodiment of the present creation. Please refer to Figure 18 , the display device 30 includes a backlight module 20 and a display panel 31. The display panel 31 is disposed opposite to the backlight module 20. Specifically, the display panel 31 is disposed opposite to the first surface S1, and each convex top 122 faces the display panel 31. Since the convex top 122 causes much less wear on the display panel 31 when contacting the display panel 31 than a sharp corner, it can effectively prevent the display panel 31 from being scratched. For example, in one embodiment, compared with the backlight module of a prism sheet with a sharp corner in the prior art, the optical film 10 of this embodiment needs to apply more pressure to the display panel 31 to possibly cause a scratch on the display panel 31. Therefore, it can effectively avoid the optical film 10 from scratching the display panel 31. In this embodiment, the display panel 31 may include a liquid crystal display panel, but the present invention is not limited thereto.

[0114] Compared with the prior art, the display device 30 of this embodiment uses the backlight module 20, so the durability can be improved and the image quality can be maintained. In other embodiments, the display device 30 may use the optical films 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h or 10i.

[0115] In summary, the optical film, backlight module, and display device according to the embodiments of the present utility model have at least one of the following advantages. The optical film of the present utility model uses a columnar body with a convex top. The convex top can significantly reduce the degree of mutual wear with other optical elements compared to the known sharp corners. The first inclined surface and the second inclined surface of the base can guide the light beam to approach forward light emission. Additionally, since the contour of the top surface of the convex top is two straight line segments with different lengths, a semi-circular arc, a quadratic Bezier curve, or a parabola, the convex top can also guide a small part of the light beam to deviate slightly from the forward light emission, thereby increasing the light guiding characteristics of the optical film. Therefore, the optical film of the present utility model can not only improve durability and maintain the effect of guiding the light beam to approach forward light emission, but also provide more diverse light guiding characteristics. The backlight module of the present utility model uses the above-mentioned optical film, so it can improve durability and maintain the luminance of the light emission. The display device of the present utility model uses the above-mentioned backlight module, so it can improve durability and maintain the image quality.

[0116] However, the above are only the preferred embodiments of the present utility model, and the scope of implementation of the present utility model cannot be limited thereby. That is, all simple equivalent changes and modifications made according to the claims and the content of the present utility model still fall within the scope covered by the patent of the present utility model. In addition, any embodiment or claim of the present utility model does not have to achieve all the purposes, advantages, or features disclosed in the present utility model. In addition, the abstract and the title (invention name) are only used to assist in the retrieval of patent documents and are not used to limit the scope of rights of the present utility model. In addition, the terms "first", "second", etc. mentioned in this specification or claims are only used to name elements or distinguish different embodiments or scopes, and are not used to limit the upper or lower limits of the number of elements.

Claims

1. An optical film, characterized in that: The optical film comprises a plate body and a plurality of columns, wherein: The plate body has a first surface and a second surface opposite to each other; and The multiple columns are arranged on the first surface, each of the multiple columns has a base and a convex top, the convex top has a top surface, the base has a first inclined surface and a second inclined surface, the top surface has a first side line and a second side line opposite to each other, the first inclined surface connects the first side line and the first surface, and the second inclined surface connects the second side line and the first surface, wherein in a cross section perpendicular to the first side line, the contour of the base is a trapezoid, and the contour of the top surface is two straight line segments of different lengths, a semicircular arc, a quadratic Bezier curve or a parabola.

2. The optical film according to claim 1, characterized in that: The contour of the top surface is the two straight line segments of different lengths, the two straight line segments include a first straight line segment and a second straight line segment, the angle between the first straight line segment and the first surface is equal to the angle between the first inclined surface and the first surface, the second straight line segment has a first endpoint and a second endpoint opposite to each other, the distance between the first endpoint and the first surface is greater than the distance between the second endpoint and the first surface, and the second straight line segment has an angle with the first surface, and the angle is greater than 0° and less than or equal to 10°.

3. The optical film according to claim 1, characterized in that: The convex top portion includes a semi-cylinder, and the axial direction of the semi-cylinder is parallel to the first side line or the second side line.

4. The optical film according to claim 1, characterized in that: The contour of the top surface includes the quadratic Bezier curve.

5. The optical film according to claim 1, characterized in that: The profile of the top surface includes the parabola, which satisfies: H = a*(W2 / 2) 2 , where H is the height of the parabola relative to the flat top line of the base, a is a constant, and the range of a includes: -48 <a<-0.12。 6. The optical film according to claim 1, characterized in that: The shapes of the convex tops of the plurality of columns are the same as each other, or the shapes of the convex tops of at least some of the plurality of columns are different from each other.

7. The optical film according to claim 1, characterized in that: The base portion of each of the multiple columns has a bottom edge and a flat top line on the cross section, the bottom edge is located on the first surface, the flat top line is parallel to the bottom edge, and the flat top line connects the first inclined surface and the second inclined surface, the length of the bottom edge is W1, the length of the flat top line is W2, 0.8≦(W1 / W1+W2)<1.

8. The optical film according to claim 7, characterized in that: 15μm≦W1≦65μm, 0.5μm≦W2≦10μm.

9. The optical film according to claim 1, characterized in that: The base portion of each of the plurality of columns has a first bottom angle and a second bottom angle, and an angle between the first bottom angle and the second bottom angle is greater than or equal to 3 degrees and less than or equal to 65 degrees.

10. The optical film according to claim 1, characterized in that: The optical film also has a plurality of light diffusion microstructures, and the plurality of light diffusion microstructures are located on the second surface of the plate.

11. The optical film according to claim 1, characterized in that: The first surface has a normal direction, and each of the plurality of convex tops is concave-convex in the normal direction.

12. The optical film according to claim 1, characterized in that: Each of the plurality of convex tops is bent left and right along the first surface.

13. The optical film according to claim 1, characterized in that: The plurality of columns are arranged along two different directions, the two directions are parallel to the first surface, and an angle between the two directions is less than 180°.

14. A backlight module, characterized in that: The backlight module includes a light emitting element, a light guide plate and an optical film, wherein: The light guide plate has a light incident surface and a light emitting surface connected to each other, and the light incident surface is opposite to the light emitting element; and The optical film is arranged opposite to the light emitting surface, and the optical film comprises a plate body and a plurality of columns, wherein: The plate body has a first surface and a second surface opposite to each other; and The multiple columns are arranged on the first surface, each of the multiple columns has a base and a convex top, the convex top has a top surface, the base has a first inclined surface and a second inclined surface, the top surface has a first side line and a second side line opposite to each other, the first inclined surface connects the first side line and the first surface, and the second inclined surface connects the second side line and the first surface, wherein in a cross section perpendicular to the first side line, the contour of the base is a trapezoid, and the contour of the top surface is two line segments of different lengths, a semicircular arc, a quadratic Bezier curve or a parabola.

15. The backlight module according to claim 14, characterized in that: The backlight module further includes a prism sheet, wherein the second surface faces the light emitting surface, and the prism sheet is disposed between the second surface and the light emitting surface.

16. The backlight module according to claim 15, characterized in that: The backlight module further includes a diffusion sheet, wherein the diffusion sheet is disposed between the prism sheet and the light emitting surface.

17. A display device, characterized in that: The display device comprises a backlight module, wherein: The backlight module includes a light emitting element, a light guide plate and an optical film, wherein: The light guide plate has a light incident surface and a light emitting surface connected to each other, and the light incident surface is opposite to the light emitting element; and The optical film is arranged opposite to the light emitting surface, and the optical film comprises a plate body and a plurality of columns, wherein: The plate body has a first surface and a second surface opposite to each other; and The multiple columns are arranged on the first surface, each of the multiple columns has a base and a convex top, the convex top has a top surface, the base has a first inclined surface and a second inclined surface, the top surface has a first side line and a second side line opposite to each other, the first inclined surface connects the first side line and the first surface, and the second inclined surface connects the second side line and the first surface, wherein in a cross section perpendicular to the first side line, the contour of the base is a trapezoid, and the contour of the top surface is two line segments of different lengths, a semicircular arc, a quadratic Bezier curve or a parabola.

Images