Light guide plate and backlight module

Abstract

The utility model discloses a light guide plate has first surface, second surface and light entrance. First surface still has first area, second area and third area in proper order. Multiple first optical microstructure is arranged in first area and second area, wherein each first optical microstructure has the curved surface of connecting first surface. Multiple second optical microstructure is arranged in second area and third area, wherein each second optical microstructure has the structure surface of connecting first surface, and the included angle of structure surface and first surface is greater than or equal to 18 DEG and less than or equal to 23 DEG. The utility model further provides a backlight module with above-mentioned light guide plate. The utility model discloses a light guide plate and backlight module can promote the luminance of light emission and light emission uniformity.

Description

Technical Field

[0001] This utility model relates to an optical element, and more particularly to a light guide plate and a backlight module having the light guide plate. Background Technology

[0002] The main components of a liquid crystal display (LCD) device include a backlight module, a display panel, and a frame. Backlight modules can be further divided into edge-lit backlight modules and direct-lit backlight modules. Generally, edge-lit backlight modules are less expensive, so most LCD devices use edge-lit backlight modules.

[0003] However, known edge-lit backlight modules still have the problem of insufficient light output, and the light guide plate of edge-lit backlight modules often exhibits hot spot phenomenon on the light input side, resulting in poor optical quality of known backlight modules.

[0004] The "Background Art" paragraph is only used to help understand the content of this 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. The content disclosed in the "Background Art" paragraph does not mean that the content or the problems to be solved by one or more embodiments of this utility model were known or recognized by those skilled in the art prior to this application. Utility Model Content

[0005] This invention provides a light guide plate to improve the brightness and uniformity of light emitted from the light-emitting surface.

[0006] This invention provides a backlight module to improve brightness and optical quality.

[0007] Other objects and advantages of this utility model can be further understood from the technical features disclosed herein.

[0008] To achieve one, some, or all of the above objectives, or other objectives, an embodiment of the present invention provides a light guide plate, including a body, a plurality of first optical microstructures, and a plurality of second optical microstructures. The body has a first surface, a second surface, and a light-incident surface. The first surface and the second surface are opposite to each other, and the light-incident surface is connected to the first surface and the second surface. In a first direction, the first surface further has a first region, a second region, and a third region in sequence, the first region being located between the light-incident surface and the second region, and the first direction being perpendicular to the light-incident surface. The first optical microstructures are disposed in the first region and the second region, wherein each first optical microstructure has a curved surface connecting to the first surface. The second optical microstructures are disposed in the second region and the third region, wherein each second optical microstructure has a structural surface connecting to the first surface, and the angle between the structural surface and the first surface is greater than or equal to 18° and less than or equal to 23°.

[0009] To achieve one, some, or all of the above-mentioned objectives, or other objectives, an embodiment of the present invention provides a backlight module including the aforementioned light guide plate, multiple light-emitting elements, a first prism sheet, and a second prism sheet. The light-emitting elements are disposed opposite to the light-incident surface. The first prism sheet is disposed opposite to the light guide plate, with its second surface facing the first prism sheet, wherein the first prism sheet has multiple first prism structures. The second prism sheet is disposed on the side of the first prism sheet opposite to the light guide plate, wherein each second prism sheet has multiple second prism structures.

[0010] The light guide plate of this invention employs a first optical microstructure and a second optical microstructure. The first optical microstructure has a curved surface and is distributed from a first region near the light-incident surface to a second region, thereby improving the light emission uniformity of the first and second regions through the curved surface. Therefore, the light guide plate of this invention improves the hot spot phenomenon on the light-incident side of the light guide plate through the first optical microstructure, thus enhancing optical quality. On the other hand, the angle between the structural surface of the second optical microstructure and the first surface is between 18° and 23°, and the second optical microstructure is distributed from the second region to a third region away from the light-incident surface, thereby improving the light emission brightness on the side of the light guide plate away from the light-incident surface and making the light emission brightness of the first, second, and third regions more consistent, further improving the light emission uniformity of the light guide plate. Based on the above, the light guide plate of this invention can effectively improve the light emission brightness and light emission uniformity of the light-emitting surface (i.e., the second surface) through the first and second optical microstructures. The backlight module of this utility model adopts the aforementioned light guide plate, first prism sheet, and second prism sheet. The first prism sheet and the second prism sheet can further enhance the brightness. Therefore, the backlight module of this utility model can effectively improve the brightness and optical quality.

[0011] To make the above and other objects, features and advantages of this utility model more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings for detailed explanation. Attached Figure Description

[0012] Figure 1 This is a top view schematic diagram of a light guide plate according to an embodiment of the present invention.

[0013] Figure 2 yes Figure 1 A partial cross-sectional view of the light guide plate.

[0014] Figure 3 yes Figure 1 A schematic diagram of the end face of the first optical microstructure.

[0015] Figure 4 yes Figure 1 A three-dimensional schematic diagram of the first optical microstructure.

[0016] Figure 5 yes Figure 1 A cross-sectional schematic diagram of the first optical microstructure.

[0017] Figure 6 yes Figure 1 A schematic diagram showing the change in the proportion of the first optical microstructure and the second optical microstructure in the first direction.

[0018] Figure 7 This is a schematic diagram showing the change in the proportion of the first optical microstructure and the second optical microstructure in the first direction according to another embodiment of the present invention.

[0019] Figure 8 This is a top view schematic diagram of the light guide plate according to another embodiment of the present invention.

[0020] Figure 9 yes Figure 8 A partial cross-sectional view of the light guide plate.

[0021] Figure 10 This is a side view schematic diagram of a backlight module according to an embodiment of the present invention.

[0022] Figure 11 yes Figure 10 A partially enlarged schematic diagram of the first prism of the backlight module.

[0023] Figure 12 yes Figure 10 A schematic diagram showing the relationship between the horizontal viewing angle and the output luminance of a backlight module in an embodiment.

[0024] Figure 13 This is a side view schematic diagram of a backlight module according to an embodiment of the present invention.

[0025] Figure 14 yes Figure 13 A schematic diagram showing the relationship between the horizontal viewing angle and the output luminance of a backlight module in an embodiment.

[0026] Explanation of reference numerals in the attached figures: 100, 100a: Light guide plate 110, 110a: Ontology 111: First side 112: Second side 113: Display Area 114: Non-display area 130: First optical microstructure 131: Curved Surface 131E: Curved Edge 132: End face 132E: Bottom edge 140: Second optical microstructure 141: Structural plane 200, 200a: Backlight module 210: Light-emitting element 220, 220a: First prism sheet 221, 221a: First prism structure 222: First Plate 230: Second Prism Slide 231: Second Prism Structure 232: Second Plate 240: Optical film 250: Reflective sheet 260: Diffusion sheet A0: Blank area A1: First Area A2: Second Area A3: Third Area A10: Region B1, B2, B3: Beams D1: First Direction D2: Second Direction E: Edge E1, E1a: First extension direction E2: Second extension direction ES: Extended Plane F: Planar part H: Distance IA, IA1, IA2: included angle IS: Light-receiving surface L: Distance L0: Body length L1: First Length L2: Second Length N1, N2: Normal direction P: Vertex P1, P2: Endpoints R: Rounded corner RL: Ridge line S1: First surface S2: Second surface SS: Side view T: Top T1: First vertex T2: Second vertex TL1: First ridge line TL2: First Ridge W: Length X: Distance. Detailed Implementation

[0027] The foregoing description and other technical contents, features, and effects of this utility model will be clearly presented in the following detailed description of one of the preferred embodiments with reference to the accompanying drawings. The directional terms mentioned in the following embodiments, such as up, down, left, right, front, or back, are only for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for illustrative purposes and not for limiting the scope of this utility model.

[0028] Figure 1 This is a top view schematic diagram of a light guide plate according to an embodiment of the present invention. Figure 2 yes Figure 1 A partial cross-sectional view of the light guide plate. Please refer to... Figure 1 and Figure 2 The light guide plate 100 includes a body 110, a plurality of first optical microstructures 130, and a plurality of second optical microstructures 140. The body 110 has a first surface S1, a second surface S2, and a light-incident surface IS. The first surface S1 and the second surface S2 are opposite to each other, and the light-incident surface IS connects the first surface S1 and the second surface S2. In one embodiment, the first surface S1 is, for example, parallel to the second surface S2, and the light-incident surface IS is, for example, perpendicular to the first surface S1. The first surface S1 may have a first side 111 and a second side 112 opposite to each other, and the first side 111 is connected to the light-incident surface IS. In a first direction D1 from the first side 111 to the second side 112, the first surface S1 also sequentially has a first region A1, a second region A2, and a third region A3. The first region A1 is located between the light-incident surface IS and the second region A2, and the first direction D1 is, for example, perpendicular to the light-incident surface IS. In this embodiment, the first region A1 is, for example, connected to the light-incident surface IS. A first optical microstructure 130 is disposed in a first region A1 and a second region A2, wherein each first optical microstructure 130 has a curved surface 131 connecting to a first surface S1. A second optical microstructure 140 is disposed in a second region A2 and a third region A3, wherein each second optical microstructure 140 has a structural surface 141 connecting to the first surface S1, and the angle IA between the structural surface 141 and the first surface S1 is greater than or equal to 18° and less than or equal to 23°.

[0029] In detail, the material of the light guide plate 100 may include plastic, glass, or other materials suitable for light transmission. For example, in this embodiment, the material of the light guide plate 100 may include polymethyl methacrylate (PMMA); however, in other embodiments, the material of the light guide plate 100 may include cycloolefin polymer (COP) or polycarbonate (PC). Furthermore, the light guide plate 100 of this embodiment can be manufactured by thermoforming or injection molding, but this invention does not impose further limitations on this.

[0030] The light-incident surface IS of the body 110 of the light guide plate 100 can be connected to the light-emitting element 210 (drawn on...). Figure 10 The light guide plate 100 is arranged relative to the light-emitting element 210 so that the light beams (e.g., beams B1, B2, and B3) generated by the light-emitting element 210 enter the light guide plate 100. The first region A1 is the region of the first surface S1 closest to the light-incident surface IS, the third region A3 is the region of the first surface S1 furthest from the light-incident surface IS, and the second region A2 is located between the first region A1 and the third region A3. The second surface S2 can be used for the light beam to exit.

[0031] The second surface S2 may include a display area 113 and a non-display area 114. The non-display area 114 is connected to the light-incident surface IS and is located between the display area 113 and the light-incident surface IS. At least a portion of the first optical microstructure 130 may overlap the non-display area 114. For example, in this embodiment, a portion of the first optical microstructure 130 overlaps the non-display area 114 on the normal N1 of the first surface S1. Further, the first region A1 includes region A10, which overlaps the non-display area 114. Since the non-display area 114 is closer to the light-incident surface IS than the display area 113, a portion of the first optical microstructure 130 may be distributed in region A10 of the first region A1 that overlaps the non-display area 114, so as to uniformly reflect the light beam incident on region A10 to the second surface S2 for emission. In this way, the light emission uniformity of the non-display area 114 and the portion of the display area 113 near the non-display area 114 can be improved by the first optical microstructure 130, making the light emission brightness of the side of the second surface S2 near the light incident surface IS more uniform, thereby further improving the optical quality of the light guide plate 100.

[0032] Incidentally, the display area 113 is connected to the side of the non-display area 114 that is opposite to the light-incident surface IS. In one embodiment, the light guide plate 100 may be disposed opposite to the display panel (not shown) and equipped with the light-emitting element 210 (shown on the diagram). Figure 10 The image is generated. The area of ​​the non-display area 114 can be determined according to the display panel described above. For example, the display area 113 overlaps with the display screen of the display panel, and the non-display area 114 is the area of ​​the display area 113 from the boundary of the light-incident surface IS to the light-incident surface IS. This utility model does not impose any further limitations on this. The features of the light guide plate 100 will be described first below, and the features of the light-emitting element 210 will be described in subsequent paragraphs.

[0033] In this embodiment, the first optical microstructure 130 is distributed in the first region A1 and the second region A2. Furthermore, the first region A1 and the second region A2 are closer to the incident light surface IS than the third region A3. Due to the diffusion characteristics of the curved surface 131 of the first optical microstructure 130 (e.g., further propagating the light beam in a direction parallel to the incident light surface IS and the first surface S1), the light beam incident on the first region A1 and the second region A2 can be uniformly reflected by the first optical microstructure 130 and exited onto the second surface S2, thereby improving the optical quality of the light guide plate 100. For example, after being reflected by the first optical microstructure 130, light beams B1 and B2 can exit from the second surface S2 at completely different angles.

[0034] In this embodiment, the first optical microstructure 130 may be a recessed microstructure, recessed on the first surface S1, with the curved surface 131 facing the incident light surface IS. After the light beam is transmitted in the body 110 (e.g., by total internal reflection from the first surface S1 and the second surface S2) to the curved surface 131, the curved surface 131 can guide (e.g., by total internal reflection or at least partial total internal reflection) the light beam towards the second surface S2. Furthermore, the curved surface 131 can uniformly reflect the light beam incident on the first optical microstructure 130 to the second surface S2 and exit. Further, the curved surface 131 of each first optical microstructure 130 may be bent towards the incident light surface IS to further enhance the diffusion effect of the curved surface 131 on the incident light beam, allowing the light beam incident on the first region A1 and the second region A2 to be more uniformly reflected by the first optical microstructure 130 to the second surface S2 for exit. However, in one embodiment, the first optical microstructure 130 may protrude from the first surface S1, and the curved surface 131 may protrude from the side of the light guide plate 100 that has the light incident surface IS.

[0035] The first optical microstructure 130 is further described below. Figure 3 yes Figure 1 A schematic diagram of the end face of the first optical microstructure. Figure 4 yes Figure 1 A three-dimensional schematic diagram of the first optical microstructure. Figure 5 yes Figure 1 A cross-sectional schematic diagram of the first optical microstructure. It should be noted that, in order to clearly present the first optical microstructure 130, Figure 4 The outline of the first optical microstructure 130 recessed on the first surface S1 is drawn in solid lines. Figure 5 The cross-section is, for example, perpendicular to the incident light surface IS and the first surface S1 and passes through the highest point of the first optical microstructure 130.

[0036] Please refer to this first. Figure 2 and Figure 3In this embodiment, the width (i.e., distance L) of each first optical microstructure 130 in the first direction D1 can be between 8 μm and 30 μm, the length W in the second direction D2 can be between 8 μm and 30 μm, and the height (i.e., distance H) in the normal N1 of the first surface S1 can be between 1 μm and 12 μm. The second direction D2 is, for example, perpendicular to the first direction D1 and the normal N1. It should be noted that the body 110 may have a side surface SS (drawn on) connecting the first surface S1, the second surface S2, and the light-incident surface IS. Figure 1 The second direction D2 can be the normal to the side SS. Each first optical microstructure 130 also has an end face 132 (also marked as...). Figure 4 and Figure 5 The end face 132 connects the curved surface 131 and the first surface S1. The curved surface 131 has an edge E connecting the end face 132, and the maximum distance (i.e., distance H) between the edge E and the first surface S1 can be between 1 μm and 12 μm. In other words, the height of each first optical microstructure 130 on the normal N1 can be between 1 μm and 12 μm. Specifically, the edge E has a top T, and in one embodiment, the distance H between the top T and the first surface S1 can be between 1 μm and 12 μm. The distance H is, for example, the distance between the top T and the first surface S1 on the normal N1 of the first surface S1 (also drawn on the...). Figure 1 The distance on ).

[0037] On the other hand, please refer to Figure 3 and Figure 4 In this embodiment, the end face 132 may have a flat portion F and a rounded corner portion R, wherein the rounded corner portion R connects the curved surface 131 and the flat portion F, and the top T may be located at the rounded corner portion R. Additionally, the edge E has two endpoints P1 and P2, which are located on the first surface S1, and the distance (i.e., length W) between the two endpoints P1 and P2 is between 8 μm and 30 μm. In other words, the length W of each first optical microstructure 130 in the second direction D2 may be between 8 μm and 30 μm. Furthermore, the edge E is curved, and in one embodiment, the curvature of the edge E may be between 5 μm and 30 μm.

[0038] Please refer to Figure 4 and Figure 5 Each first optical microstructure 130 has a curved bottom edge 131E connecting to the first surface S1, and an end face 132 having a bottom edge 132E connecting to the first surface S1. The curved bottom edge 131E has a vertex P protruding away from the bottom edge 132E. The distance L between the vertex P and the bottom edge 132E (marked on...) Figure 5The width of each first optical microstructure 130 in the first direction D1 can be between 8 μm and 30 μm. Specifically, the curved bottom edge 131E can be approximately parabolic, and the vertex P can be the vertex of the parabola. In this embodiment, the distance L is, for example, the normal N2 (also labeled) between the vertex P and the bottom edge 132E on the incident light surface IS. Figure 2 The distance on the surface. Additionally, each of the first optical microstructures 130 has a ridge RL on its curved surface 131 relative to the first surface S1. In one embodiment, the radius of curvature of the ridge RL may be between 90 μm and 200 μm. Specifically, in this embodiment, the ridge RL extends, for example, from the top T of the end face 132 to the vertex P of the curved bottom edge 131E, and the curved surface 131 may be substantially symmetrical about the ridge RL.

[0039] Please refer to this again. Figure 1 and Figure 2 Incidentally, the dimensions of each of the first optical microstructures 130 can be substantially the same to provide a more consistent optical effect. However, in one embodiment, at least some of the first optical microstructures 130 may have different dimensions, and at least some of the first optical microstructures 130 may be unevenly distributed within the first region A1 and / or the second region A2, thereby providing different optical effects. This invention does not impose further limitations on this.

[0040] Furthermore, in this embodiment, the second optical microstructure 140 is distributed in the second region A2 and the third region A3. More specifically, the second region A2 and the third region A3 are farther from the incident light surface IS than the first region A1, and the second optical microstructure 140 can reflect the light beam to be incident on the second surface S2 at a small angle (i.e., the angle between the light beam and the normal of the second surface S2), thereby increasing the positive light emission brightness on the side of the second surface S2 away from the incident light surface IS. For example, after the light beam B3 is reflected to the second surface S2 by the second optical microstructure 140, it can exit from the second surface S2 in a near-positive direction, thereby improving the light emission brightness of the light guide plate 100 and making the light emission brightness of the first region A1, the second region A2, and the third region A3 of the second surface S2 more consistent.

[0041] The second optical microstructure 140 may be a recessed microstructure, recessed within the first surface S1, with each structural surface 141 of the second optical microstructure 140 facing the incident light surface IS to facilitate the reflected light beam being incident on the second surface S2 at a small angle. For example, the structural surface 141 of the second optical microstructure 140 may be a plane facing the incident light surface IS. In one embodiment, the second optical microstructure 140 may protrude from the first surface S1, and each structural surface 141 may be located on the side of the second optical microstructure 140 opposite to the incident light surface IS. Alternatively, in embodiments where the second optical microstructure 140 protrudes from the first surface S1, each structural surface 141 may be, for example, a plane.

[0042] Similarly, in this embodiment, the dimensions of each of the second optical microstructures 140 may be equal to each other and may be distributed in the second region A2 and the third region A3. However, in one embodiment, at least some of the dimensions of the second optical microstructures 140 may be different from each other and may be distributed differently in the second region A2 and the third region A3 to provide different optical effects. In this embodiment, the dimensions of each of the first optical microstructures 130 and the dimensions of each of the second optical microstructures 140 may be equal, but in other embodiments, the dimensions of at least some of the first optical microstructures 130 may be different from the dimensions of at least some of the second optical microstructures 140, and the distribution density of the first optical microstructures 130 and / or the second optical microstructures 140 may be changed to adjust the optical effect of the light guide plate 100.

[0043] In detail, Figure 6 yes Figure 1 A schematic diagram showing the change in the proportion of the first optical microstructure and the second optical microstructure in the first direction, wherein... Figure 6 The distance X is, for example, the shortest distance between the microstructure location and the incident light surface IS, where the distance X is between 0 and L1. Figure 1 The first region A1 corresponds to a distance X between L1 and L1+L2, which corresponds to the second region A2. Regions with a distance X greater than L1+L2 correspond to the third region A3. Please refer to [reference needed]. Figure 1 and Figure 6The proportion of the first optical microstructure 130 located in the second region A2 decreases linearly along the first direction D1, while the proportion of the second optical microstructure 140 located in the second region A2 increases linearly along the first direction D1. The proportion is calculated, for example, by taking the number of microstructures at the same distance X as 100% and determining the percentage occupied by the first optical microstructure 130 (or the second optical microstructure 140). In one embodiment, the distribution density of optical microstructures (including the first optical microstructure 130 and the second optical microstructure 140) on the first surface S1 remains consistent. Therefore, it can also be said that the number of the first optical microstructure 130 located in the second region A2 decreases linearly along the first direction D1, while the number of the second optical microstructure 140 located in the second region A2 increases linearly along the first direction D1. This makes the light output brightness of the second surface S2 more uniform, thereby further improving the optical quality of the light guide plate 100. Specifically, no second optical microstructure 140 is provided in the first region A1, therefore the percentage of first optical microstructure 130 in the first region A1 is 100%. In the second region A2, the number of first optical microstructures 130 decreases linearly in the first direction D1, while the number of second optical microstructures 140 increases linearly in the first direction D1. Furthermore, there are no first optical microstructures 130 in the third region A3, while the percentage of second optical microstructures 140 in the third region A3 is 100%.

[0044] Incidentally, in one embodiment, in the first direction D1, the first length L1 of the first region A1 may account for 5% to 20% of the body length L0 of the first surface S1. Similarly, in the first direction D1, the second length L2 of the second region A2 may account for 5% to 20% of the body length L0 of the first surface S1.

[0045] Figure 7 This is a schematic diagram showing the change in the proportion of the first optical microstructure and the second optical microstructure in the first direction according to another embodiment of the present invention. It is understood that the change in the number of the first optical microstructure 130 and the second optical microstructure 140 within the second region A2 is not limited to... Figure 6 The linear change is shown. For example, please refer to... Figure 1 and Figure 7 In another embodiment, the proportion of the first optical microstructure 130 located in the second region A2 can decrease non-linearly in the first direction D1, while the proportion of the second optical microstructure 140 located in the second region A2 can increase non-linearly in the first direction D1, so that the light guide plate 100 can provide different optical effects.

[0046] For example, the coordinate of the light guide plate 100 in the first direction D1 is X, the probability of the first optical microstructure 130 appearing in X is represented by PA(X), and the probability of the second optical microstructure 140 appearing in X is represented by PB(X).

[0047] When 0 ≦ X < L1, PA(X) = 1; When L1≦X<L1+L2, PA(X)=cos 2 (X), PB(X) = sin 2 (X), and PA(X)+PB(X)=1; When X≧L1+L2, PB(X)=1.

[0048] It should be noted that PA(X)=1 indicates that the proportion of the first optical microstructure 130 at position X on the light guide plate 100 is 100%, and PA(X)=0 indicates that the proportion of the first optical microstructure 130 at position X on the light guide plate 100 is 0%. PB(X) presents the proportion of the second optical microstructure 140 in the same way as PA(X), so the relevant description is omitted here.

[0049] In simple terms, within the first region A1 (i.e., 0 ≦ X < L1), the proportion of the first optical microstructure 130 can be 100%, while the proportion of the second optical microstructure 140 can be 0%. Similarly, within the third region A3 (i.e., X ≧ L1 + L2), the proportion of the first optical microstructure 130 can be 0%, while the proportion of the second optical microstructure 140 can be 100%. Furthermore, within the second region A2 (i.e., L1 ≦ X < L1 + L2), the proportion of the first optical microstructure 130 can decrease non-linearly, while the proportion of the second optical microstructure 140 can increase non-linearly.

[0050] In another embodiment, PA(X) and PB(X) are as follows: When 0 ≦ X < L1, PA(X) = 1; When L≦X<L+L1, PA(X)= aX 3 +bX 2 +cX+d, PB(X)=1-PA(X), and 0≦PA(X)≦1, 0≦PB(X)≦1; When X≧L1+L2, PB(X)=1.

[0051] It should be noted that a, b, c, and d are constants.

[0052] Compared to known technologies, the light guide plate 100 of this embodiment employs a first optical microstructure 130 and a second optical microstructure 140. The first optical microstructure 130 has a curved surface 131 and is distributed from a first region A1 near the light incident surface IS to a second region A2, thereby improving the light emission uniformity of the first region A1 and the second region A2 through the curved surface 131. Therefore, the light guide plate 100 of this embodiment improves the hot spot phenomenon on the light incident side through the first optical microstructure 130, thereby improving the optical quality. On the other hand, the angle IA between the structural surface 141 of the second optical microstructure 140 and the first surface S1 is between 18° and 23°, and the second optical microstructure 140 is distributed from the second region A2 to a third region A3 away from the light incident surface IS, thereby improving the light emission brightness on the side of the light guide plate 100 away from the light incident surface IS, and making the light emission brightness of the first region A1, the second region A2, and the third region A3 more consistent, thereby further improving the light emission uniformity of the light guide plate 100. Based on the above, the light guide plate 100 of this embodiment can effectively improve the light output brightness and light output uniformity of the light output surface (i.e., the second surface S2) through the first optical microstructure 130 and the second optical microstructure 140.

[0053] Figure 8 This is a top view schematic diagram of the light guide plate according to another embodiment of the present invention. Figure 9 yes Figure 8 A partial cross-sectional view of the light guide plate. The structure and advantages of the light guide plate 100a in this embodiment are similar to those of the light guide plate 100a in this embodiment. Figure 1 The following describes only the differences in the embodiments. Please refer to... Figure 8 and Figure 9 In this embodiment, the first region A1 of the first optical microstructure 130 is not connected to the incident surface IS. The first surface S1 has a blank region A0 between the first region A1 and the incident surface IS. The blank region A0 is located between the incident surface IS and the first region A1, and the blank region A0 does not have any microstructures. In this embodiment, the blank region A0 overlaps, for example, with the non-display area 114. The first optical microstructures 130 of the body 110a are all located in the region of the first surface S1 corresponding to the display area 113, while the region of the first surface S1 corresponding to the non-display area 114 does not have the first optical microstructure 130. This prevents the light beam from exiting prematurely in the non-display area 114, allowing most of the light beam to exit from the display area 113, thus increasing the brightness and providing different optical effects. Figure 8 In a modified embodiment of the embodiment, at least a portion of the blank area A0 may overlap with the display area 113, or at least a portion of the first area A1 may overlap with the non-display area 114.

[0054] Figure 10 This is a side view schematic diagram of a backlight module according to an embodiment of this utility model. Please refer to it. Figure 10The backlight module 200 includes a light guide plate 100, a plurality of light-emitting elements 210, a first prism sheet 220, and a second prism sheet 230. The light-emitting elements 210 are disposed opposite to the light-incident surface S1. The first prism sheet 220 is disposed opposite to the light guide plate 100, with its second surface S2 facing the first prism sheet 220, wherein the first prism sheet 220 has a plurality of first prism structures 221. The second prism sheet 230 is disposed on the side of the first prism sheet 220 opposite to the light guide plate 100, wherein each second prism sheet 230 has a plurality of second prism structures 231.

[0055] The light-emitting element 210 may include a light-emitting diode (LED). Furthermore, the number of LEDs may be multiple, and the emission wavelength may include blue light or white light, but the present invention does not impose any restrictions on this.

[0056] Figure 11 yes Figure 10 A partially enlarged schematic diagram of the first prism of the backlight module. Please refer to... Figure 10 and Figure 11 The first prism sheet 220 can be a regular prism sheet. Each first prism structure 221 has a first apex angle T1, the angle of which is, for example, greater than 90°, and each first prism structure 221 extends along a first extending direction E1. The angle IA1 between the first extending direction E1 and the extending plane ES of the incident light surface IS can be greater than 75° and less than or equal to 90°. Thus, the first prism structure 221 can diffuse the light beam through the first apex angle T1 to increase the brightness of the backlight module 200 at a wide viewing angle, thereby increasing the viewing angle of the backlight module 200 at a horizontal viewing angle. In this embodiment, the first extending direction E1 is substantially parallel to the X direction, the extending plane ES is substantially parallel to the YZ plane, and the angle IA1 in this embodiment is approximately 90°. In one embodiment, the first apex angle T1 is, for example, between 120° and 130°, but other embodiments are not limited to this. Incidentally, the first prism sheet 220 in this embodiment may also have a first plate 222. The first prism structure 221 is located on the side of the first plate 222 opposite to the light guide plate 100, and the first apex T1 is located on the side of the first prism structure 221 opposite to the first plate 222. In addition, the side of the first prism structure 221 opposite to the first plate 222 may have a first ridge line TL1, and the first extension direction E1 is, for example, the extension direction of the first ridge line TL1.

[0057] The second prism sheet 230 can be a positive prism sheet. Each second prism structure 231 extends along a second extending direction E2, and the angle between the second extending direction E2 and the extending plane ES of the incident light surface IS can be less than 15°. In this way, the second prism sheet 230 can guide the light beam to be emitted close to the forward direction, thereby improving the forward brightness of the backlight module 200. In this embodiment, the second extending direction E2 is substantially parallel to the direction Z, and the angle between the second extending direction E2 and the extending plane ES of the incident light surface IS is approximately 0°. Similarly, the second prism sheet 230 may also have a second plate 232. The second prism structure 231 is located on the side of the second plate 232 opposite to the light guide plate 100, and the side of the second prism structure 231 opposite to the second plate 232 may have a first ridge line TL2. The second extending direction E2 is, for example, the extending direction of the first ridge line TL2. In addition, the side of the second prism structure 231 facing away from the second plate 232 may also have a second apex angle T2, and in one embodiment, the angle of the second apex angle T2 is, for example, about 90°, but the present invention does not impose any further limitations on this.

[0058] Incidentally, in this embodiment, the refractive index of the first prism 220 is, for example, greater than that of the second prism 230, enabling the first prism 220 to guide the light beam out at a larger angle, thereby further improving the viewing angle of the backlight module 200 in the horizontal viewing angle. For example, in one embodiment, the refractive index of the first prism 220 may be 1.65 or higher, and the refractive index of the second prism 230 may be approximately 1.56, but this invention does not impose further limitations on these aspects.

[0059] Compared to known technologies, the backlight module 200 of this embodiment uses a light guide plate 100, a first prism sheet 220 and a second prism sheet 230, wherein the first prism sheet 220 and the second prism sheet 230 can further enhance the brightness. Therefore, the backlight module 200 of this embodiment can effectively improve the brightness and optical quality.

[0060] Figure 12 yes Figure 10 A schematic diagram illustrating the relationship between the horizontal viewing angle and the emitted luminance of a backlight module in one embodiment. Please refer to... Figure 12 The backlight module 200 has a significantly improved light output brightness between -50° and -30° and between +30° and +50° at a horizontal viewing angle. Therefore, the viewing angle of the backlight module 200 at a horizontal viewing angle (e.g., a viewing angle range where the brightness is more than 30% of the maximum brightness) can reach -55° to +55°.

[0061] Please refer to this again. Figure 10The backlight module 200 may also include an optical film 240, which may be disposed on the side of the second prism sheet 230 opposite to the first prism sheet 220. In this embodiment, the optical film 240 may include a dual brightness enhancement film (DBEF) to further enhance the light output brightness of the backlight module 200.

[0062] On the other hand, the backlight module 200 may also include, for example, a reflective sheet 250, which is disposed on the side of the light guide plate 100 opposite to the first prism sheet 220, to improve the light utilization rate of the backlight module 200. The material of the reflective sheet 250 may include, for example, silver, but the present invention does not impose any restrictions on this.

[0063] Figure 13 This is a side view schematic diagram of a backlight module according to an embodiment of the present invention. Figure 14 yes Figure 13 A schematic diagram showing the relationship between the horizontal viewing angle and the emitted luminance of a backlight module in one embodiment. The structure and advantages of the backlight module 200a in this embodiment are similar to those of... Figure 10 The following describes only the differences in the embodiments. Please refer to [the previous text]. Figure 13 The first prism sheet 220a is, for example, a reverse prism sheet (the prism is disposed on the light-incident surface of the prism sheet), and the second prism sheet 230 is a positive prism sheet (the prism is disposed on the light-outceasing surface of the prism sheet). Each first prism structure 221a extends along a first extending direction E1a and is disposed on the side of the first prism sheet 220a facing the light guide plate 100. Each second prism structure 231 extends along a second extending direction E2. The angle IA2 between the first extending direction E1a and the extending plane ES of the light-incident surface IS can be greater than 75° and less than or equal to 90°. Similarly, in this embodiment, the first extending direction E1a can be substantially parallel to direction X, the extending plane ES can be substantially parallel to the YZ plane, and the angle IA2 can be approximately 90°, but other embodiments are not limited to this. On the other hand, the angle between the second extending direction E2 and the extending plane ES of the incident light surface IS can be less than 15°. In this embodiment, the second extending direction E2 can be substantially parallel to the direction Z, and the angle between the second extending direction E2 and the extending plane ES can be approximately 0°.

[0064] In detail, the first extension direction E1a of the first prism structure 221a is substantially perpendicular to the extension plane ES. Therefore, the first prism sheet 220a can guide the light beam to separate in the direction of the horizontal viewing angle to form two brightness peaks. The second extension direction E2 of the second prism structure 231 is substantially parallel to the extension plane ES. Therefore, the second prism sheet 230 can enhance the forward brightness of the backlight module 200a, thereby further enhancing the two brightness peaks mentioned above. For example, please refer to... Figure 14The luminance of the backlight module 200a at horizontal viewing angle is mainly distributed in two horizontal viewing angle ranges, with the two luminance peaks located at -50° to -20° and +20° to +50°, respectively.

[0065] Please refer to this again. Figure 13 Incidentally, the backlight module 200a may also include a diffuser 260, which is located between the first prism sheet 220a and the light guide plate 100 to further improve the optical quality of the backlight module 200a.

[0066] In summary, the light guide plate and backlight module of the present invention have at least one of the following advantages. The light guide plate of the present invention employs a first optical microstructure and a second optical microstructure. The first optical microstructure has a curved surface and is distributed from a first region near the light-incident surface to a second region, thereby improving the light emission uniformity of the first and second regions through the curved surface. Therefore, the light guide plate of the present invention improves the hot spot phenomenon on the light-incident side of the light guide plate through the first optical microstructure, thereby improving optical quality. On the other hand, the angle between the structural surface of the second optical microstructure and the first surface is between 18° and 23°, and the second optical microstructure is distributed from the second region to a third region away from the light-incident surface, thereby improving the light emission brightness on the side of the light guide plate away from the light-incident surface and making the light emission brightness of the first, second, and third regions more consistent, thereby further improving the light emission uniformity of the light guide plate. Based on the above, the light guide plate of the present invention can effectively improve the light emission brightness and light emission uniformity of the light-emitting surface (i.e., the second surface) through the first and second optical microstructures. The backlight module of this utility model adopts the aforementioned light guide plate, first prism sheet, and second prism sheet. The first prism sheet and the second prism sheet can further enhance the brightness. Therefore, the backlight module of this utility model can effectively improve the brightness and optical quality.

[0067] The above description is merely a preferred embodiment of this utility model and should not be construed as limiting the scope of this utility model. Any simple equivalent changes and modifications made in accordance with the claims and content of this utility model shall still fall within the scope of this utility model patent. Furthermore, no embodiment or claim of this utility model needs to achieve all the objectives, advantages, or features disclosed in this utility model. In addition, the abstract and title of the utility model are only used to assist in patent document retrieval and are not intended to limit the scope of this utility model. Furthermore, 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 limit of the number of elements.

Claims

1. A light guide plate, characterized in that, The light guide plate includes a body, multiple first optical microstructures, and multiple second optical microstructures, wherein: The body has a first surface, a second surface, and a light-incident surface. The first surface and the second surface are opposite to each other. The light-incident surface connects the first surface and the second surface. In a first direction, the first surface also has a first region, a second region, and a third region in sequence. The first region is located between the light-incident surface and the second region, and the first direction is perpendicular to the light-incident surface. The plurality of first optical microstructures are disposed in the first region and the second region, wherein each of the plurality of first optical microstructures has a curved surface connecting to the first surface; and The plurality of second optical microstructures are disposed in the second region and the third region, wherein each of the plurality of second optical microstructures has a structural surface that connects to the first surface, and the angle between the structural surface and the first surface is greater than or equal to 18° and less than or equal to 23°.

2. The light guide plate according to claim 1, characterized in that, The plurality of first optical microstructures and the plurality of second optical microstructures are recessed in the first surface, and the structural surface of each of the plurality of second optical microstructures faces the light incident surface.

3. The light guide plate according to claim 1, characterized in that, The curved surface of each of the plurality of first optical microstructures protrudes toward the light-incident surface.

4. The light guide plate according to claim 1, characterized in that, In the first direction, the first length of the first region accounts for 5% to 20% of the body length of the first surface.

5. The light guide plate according to claim 1, characterized in that, In the first direction, the second length of the second region accounts for 5% to 20% of the body length of the first surface.

6. The light guide plate according to claim 1, characterized in that, The second surface includes a display area and a non-display area, the non-display area being connected to the light-incident surface and located between the display area and the light-incident surface, and at least a portion of the plurality of first optical microstructures overlapping the non-display area.

7. The light guide plate according to claim 1, characterized in that, The first surface also has a blank area, which is disposed between the light-incident surface and the first area, and the blank area is not provided with microstructures.

8. The light guide plate according to claim 1, characterized in that, The number of the plurality of first optical microstructures located in the second region decreases linearly or non-linearly in the first direction, while the number of the plurality of second optical microstructures located in the second region increases linearly or non-linearly in the first direction.

9. The light guide plate according to claim 1, characterized in that, Each of the plurality of first optical microstructures has a width of 8µm to 30µm in the first direction, a length of 8µm to 30µm in the second direction, and a height of 1µm to 12µm in the normal direction of the first surface, wherein the second direction is perpendicular to the first direction and the normal direction.

10. The light guide plate according to claim 1, characterized in that, Each of the plurality of first optical microstructures further has an end face, the end face connecting the curved surface and the first surface, the curved surface having an edge connecting the end face, and the maximum distance between the edge and the first surface being between 1 μm and 12 μm, and the edge having two endpoints, the two endpoints being located on the first surface and the distance between the two endpoints being between 8 μm and 30 μm, the end face having a bottom edge connecting the first surface, the curved surface of each of the plurality of first optical microstructures having a curved bottom edge connecting the first surface, the curved bottom edge having a vertex protruding away from the bottom edge, and the maximum distance between the vertex and the bottom edge being between 8 μm and 30 μm.

11. The light guide plate according to claim 10, characterized in that, The edge is curved, and the curvature of the edge is between 5um and 30um.

12. The light guide plate according to claim 1, characterized in that, Each of the plurality of first optical microstructures has a ridge relative to the first surface, the radius of curvature of the ridge being between 90 μm and 200 μm.

13. A backlight module, characterized in that, The backlight module includes a light guide plate, multiple light-emitting elements, a first prism sheet, and a second prism sheet, wherein: The light guide plate includes a body, multiple first optical microstructures, and multiple second optical microstructures, wherein: The body has a first surface, a second surface, and a light-incident surface. The first surface and the second surface are opposite to each other. The light-incident surface connects the first surface and the second surface. In a first direction, the first surface also has a first region, a second region, and a third region in sequence. The first region is connected to the light-incident surface, and the first direction is perpendicular to the light-incident surface. The plurality of first optical microstructures are disposed in the first region and the second region, wherein each of the plurality of first optical microstructures has a curved surface connecting to the first surface; and The plurality of second optical microstructures are disposed in the second region and the third region, wherein each of the plurality of second optical microstructures has a structural surface that connects to the first surface, and the angle between the structural surface and the first surface is greater than or equal to 18° and less than or equal to 23°. The plurality of light-emitting elements are arranged opposite to the light-incident surface; The first prism sheet is disposed opposite to the light guide plate, and the second surface faces the first prism sheet, wherein the first prism sheet has a plurality of first prism structures; and The second prism sheet is disposed on the side of the first prism sheet opposite to the light guide plate, wherein each of the plurality of second prism sheets has a plurality of second prism structures.

14. The backlight module according to claim 13, characterized in that, The first prism sheet and the second prism sheet are both positive prism sheets. Each of the plurality of first prism structures has a first apex angle, the angle of the first apex angle is greater than 90°, and each of the plurality of first prism structures extends along a first extending direction. Each of the plurality of second prism structures extends along a second extending direction. The angle between the first extending direction and the extending plane of the light-incident surface is greater than 75° and less than or equal to 90°, and the angle between the second extending direction and the extending plane of the light-incident surface is less than 15°.

15. The backlight module according to claim 13, characterized in that, The first prism sheet is a reverse prism sheet, and the second prism sheet is a positive prism sheet. Each of the plurality of first prism structures extends along a first extending direction, and each of the plurality of second prism structures extends along a second extending direction. The angle between the first extending direction and the extending plane of the light-incident surface is greater than 75° and less than or equal to 90°, and the angle between the second extending direction and the extending plane of the light-incident surface is less than 15°.

16. The backlight module according to claim 15, characterized in that, The refractive index of the first prism is greater than that of the second prism.

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