TWM603123U - Light guide plate and light source module - Google Patents

Abstract

A light guide plate includes a plate body and a plurality of strip-shaped microstructures. The plate body has a light incident surface and a light exit surface, and the light exit surface is adjacent to the light incident surface. The plurality of strip-shaped microstructures is disposed on the light exit surface. Each strip-shaped microstructure has a first end and a second end and extends along an extension direction. The first end is close to the light incident surface, and the second end is far from the light incident surface. Each strip-shaped microstructure has a first gradual change portion. The first gradual change portion is adjacent to the first end and has a maximum height in a light exit direction perpendicular to the light exit surface, which gradually increases from the first end toward the second end. Each strip-shaped microstructure also has a light exit curved surface. The radius of curvature of the light exit curved surface perpendicular to the extension direction is the same from the first end to the second end. A light source module having the light guide plate is further provided.

Description

Light guide plate and light source module

This creation is related to a light source module, and particularly to a light guide plate and a light source module using the light guide plate.

Generally, a liquid crystal display device includes a liquid crystal display panel and a backlight module, and since the liquid crystal display panel itself does not emit light, the backlight module is required to provide a high-brightness and high-uniformity illumination source to the liquid crystal display panel.

In advanced liquid crystal display devices, the display area is divided into multiple areas, and the brightness of the backlight module is controlled for each of the multiple areas. This approach is called dynamic partition dimming (local dimming). ). By adjusting the brightness of each area of the backlight module, the effect of high dynamic range (HDR) is achieved. In the current side-lit backlight module, a special ridge structure is arranged on the light-emitting surface of the light guide plate to converge the light pattern, thereby enhancing the effect of dynamic zone dimming.

However, after the above-mentioned conventional method converges the light type, the directivity of the light will be more obvious, so it is easy to form a hot spot with uneven brightness on the light entrance side of the light guide plate, and the place away from the light entrance side There will generally be insufficient brightness.

This "prior art" paragraph is only used to help understand the content of this creation. Therefore, the content disclosed in the "prior art" may contain some conventional technologies that do not constitute the common knowledge in the technical field. In addition, the content disclosed in the "prior art" does not represent the content or the problem to be solved by one or more embodiments of this creation, nor does it mean that it has been used by a person with ordinary knowledge in the technical field before this creation application. Know or recognize.

This creation provides a light guide plate that can improve brightness and uniformity.

This creation provides a light source module that can improve brightness and uniformity.

Other purposes and advantages of this creation can be further understood from the technical features disclosed in this creation.

In order to achieve one or part or all of the above objectives or other objectives, the light guide plate provided by an embodiment of the present creation includes a plate body and a plurality of strip-shaped microstructures. The board has a light-incident surface and a light-emitting surface, and the light-emitting surface is adjacent to the light-incident surface. A plurality of strip-shaped microstructures are arranged on the light-emitting surface. Each strip-shaped microstructure has a first end and a second end and extends along the extending direction. The first end is close to the light incident surface, and the second end is far away from the light incident surface. Each strip-shaped microstructure has a first gradual change portion, the first gradual change portion is connected to the first end and the maximum height in the first direction perpendicular to the light emitting surface gradually increases from the first end to the second end. Each strip-shaped microstructure further has a light-emitting curved surface, and the radius of curvature of the light-emitting curved surface perpendicular to the extending direction is the same from the first end to the second end.

In an embodiment of the present creation, each of the above-mentioned strip-shaped microstructures further has a flat part connected to the first gradation part and extending to the second end. The maximum height of the flat part in the first direction is from the connection to the first gradation part. From one end to the second end are the same.

In an embodiment of the present creation, the connection between the first gradation part and the flat part is rounded and chamfered.

In an embodiment of the present creation, each of the above-mentioned strip-shaped microstructures further has a second gradation part, which is connected to the first gradation part and extends to the second end. The maximum height of the second gradation part in the first direction is from the first The two ends gradually increase toward the first end.

In an embodiment of the present creation, each of the above-mentioned strip-shaped microstructures further has a flat part and a second gradation part, the flat part is connected between the first gradation part and the second gradation part, and the flat part is in the first direction. The maximum height is the same, and the maximum height of the second gradual portion in the light emitting direction gradually increases from the second end to the first end.

In an embodiment of the present creation, the length of the first gradation portion of each strip-shaped microstructure in the extending direction is half of the length of each strip-shaped microstructure in the extending direction.

In an embodiment of this creation, the aforementioned radius of curvature is 10um ~ 300um.

In an embodiment of the present creation, the aforementioned plurality of strip-shaped microstructures are arranged along the arrangement direction parallel to the light incident surface, and the extension direction is perpendicular to the light incident surface.

In an embodiment of the present creation, the above-mentioned multiple strip-shaped microstructures are arranged on the entire surface of the light emitting surface.

In an embodiment of the present creation, the above-mentioned plate further has a bottom surface, which is adjacent to the light incident surface and opposite to the light exit surface. The bottom surface has a plurality of diffusing microstructures. The direction away from the light incident surface gradually becomes denser.

In an embodiment of the present creation, the above-mentioned plate further has a bottom surface, which is adjacent to the light incident surface and opposite to the light exit surface. The bottom surface has a plurality of diffusing microstructures. The direction away from the light incident surface gradually becomes denser, and then gradually becomes thinner.

In order to achieve one or part or all of the above-mentioned purposes or other purposes, the light source module provided by an embodiment of the invention includes a plurality of first light-emitting elements and the above-mentioned light guide plate. The plurality of first light emitting elements are arranged opposite to the first light incident surface of the board.

In an embodiment of the present creation, the above-mentioned light source module further includes a plurality of second light-emitting elements, and the board further has a second light-incident surface adjacent to the light-emitting surface and opposite to the first light-incident surface. The light-emitting element is disposed relative to the second light-incident surface, and each of the strip-shaped microstructures further has a second gradation part, which is connected to the first gradation part and extends to the second end. The maximum height of the second gradation part in the first direction is from the first The two ends gradually increase toward the first end.

In the light source module of this creative embodiment, the maximum height of the first gradation part of the strip-shaped microstructure on the light guide plate in the first direction is lower than that adjacent to the first end, due to the light-emitting curved surface of the strip-shaped microstructure The radius of curvature perpendicular to the extension direction is the same from the first end to the second end. When the height is lower, the ratio of the maximum height to the maximum width is smaller, which can reduce the light output on the side adjacent to the light entrance surface. Effect, improve the hot spot phenomenon of uneven brightness; and the maximum height of the first gradient in the first direction gradually increases from the first end to the second end, so that the maximum height of the strip-shaped microstructure at the second end is higher. The higher the ratio of the maximum height to the maximum width is, the greater the light output effect can be improved, and the light output on the side of the light output surface away from the light entrance surface will have insufficient brightness. Therefore, the overall brightness uniformity of the light-emitting surface of the light guide plate can be improved.

In order to make the above and other purposes, features and advantages of this creation more obvious and easy to understand, the following is a detailed description of preferred embodiments in conjunction with the accompanying drawings.

The aforementioned and other technical content, features and effects of this creation will be clearly presented in the following detailed description of a preferred embodiment with reference to the drawings. The directional terms mentioned in the following embodiments, for example: up, down, left, right, front or back, etc., are only directions for referring to the attached drawings. Therefore, the directional terms used are used to illustrate and not to limit this creation.

FIG. 1 is a three-dimensional schematic diagram of a light source module according to an embodiment of the creation. Fig. 2 is a schematic cross-sectional view of Fig. 1. Please refer to FIGS. 1 and 2, the light source module 1 of this embodiment includes a light guide plate 10 and a plurality of first light emitting elements 20. The light guide plate 10 includes a plate body 100 and a plurality of strip-shaped microstructures 200. The board 100 has a first light-incident surface 110 and a light-emitting surface 120. The light-emitting surface 120 is adjacent to the first light-incident surface 110. The light guide plate may further include a first surface 130, and the first light-incident surface 110 and the first surface 130 relatively. In this embodiment, the light-emitting surface 120 is connected between the first light-incident surface 110 and the first surface 130, for example. The plurality of strip-shaped microstructures 200 are arranged on the light-emitting surface 120. Each strip-shaped microstructure 200 has a first end 201 and a second end 202, which are arranged along the arrangement direction A parallel to the first light incident surface 110 and extend along the extension direction E. The extension direction E is, for example, perpendicular to the first light incident surface 110, but is not limited thereto. The first end 201 is close to the first light incident surface 110, and the second end 202 is close to the first surface 130, that is, away from the first light incident surface 110. The first ends 201 of the plurality of strip-shaped microstructures 200 are, for example, disposed adjacent to the first light incident surface 110, but not limited to this. In another embodiment, the first end 201 may be disposed close to but not connected to the first light incident surface 110. The second ends 202 of the plurality of strip-shaped microstructures 200 are, for example, disposed adjacent to the first surface 130, but not limited to this. In another embodiment, the second end 202 may be arranged close to but not connected to the first surface 130.

In this embodiment, a plurality of strip-shaped microstructures 200 are, for example, evenly disposed on the entire surface of the light emitting surface 120, but it is not limited thereto. In another embodiment, the light-emitting surface 120 further has a blank area where the strip-shaped microstructure 200 is not configured, for example.

The plurality of first light emitting elements 20 are disposed opposite to the first light incident surface 110 of the board body 100 and are suitable for emitting light L1 to be incident on the first light incident surface 110. The number of the first light emitting elements 20 in FIG. 1 is three as an example, but it is not limited thereto. The first light emitting element 20 can be a light emitting diode (LED), but the invention does not limit the type of light source.

Please refer to FIG. 2, each strip-shaped microstructure 200 further has a first gradation portion 210. The first gradation portion 210 is connected to the first end 201 and is in a first direction B perpendicular to the light-emitting surface 120 (for example, the normal line of the light-emitting surface 120). The maximum height in the direction) gradually increases from the first end 201 toward the second end 202. In this embodiment, each strip-shaped microstructure 200 further has, for example, a flat portion 220 connected to the first gradient portion 210 and extending to the second end 202. The maximum height of the flat portion 220 in the first direction B is the same from the end connecting the first gradation portion 210 to the second end 202. Specifically, the first gradation portion 210 has a maximum height H1 where it is connected to the first end 201, an end of the first gradation portion 210 that is far from the first end 201 and connected to the flat portion 220 has a maximum height H2, and the flat portion 220 has a maximum height H3. . Among them, the maximum height H1 is less than the maximum height H2, and the maximum height H2 is equal to the maximum height H3. The maximum height H1 is, for example, 0.1um ~ 2um, and the maximum height H3 is, for example, 5um ~ 20um, but not limited to this. In addition, in this embodiment, the length F1 of the first gradation portion 210 of each strip-shaped microstructure 200 in the extension direction E is half of the length F2 of each strip-shaped microstructure 200 in the extension direction E, and each strip-shaped microstructure 200 The length F3 of the flat portion 220 in the extension direction E is also half of the length F2 of each strip-shaped microstructure 200 in the extension direction E, but is not limited thereto. The length F1 of the first gradation portion 210 in the extension direction E can be adjusted according to different design requirements.

3A is a schematic diagram of a side facing the first light incident surface of the light guide plate of FIG. 1. 3B is a schematic diagram of the side facing the first surface of the light guide plate of FIG. 1. Please refer to Figure 1, Figure 3A and Figure 3B, each strip-shaped microstructure 200 has a light-emitting curved surface 203. The curvature radius CR of the light-emitting curved surface 203 perpendicular to the extending direction E is the same from the first end 201 to the second end 202, and any The distance D between the centers of two adjacent strip microstructures 200 is the same from the first end 201 to the second end 202. Specifically, the radius of curvature CR is, for example, 10 um to 300 um, but it is not limited thereto.

The first gradation portion 210 of each strip-shaped microstructure 200 is connected to the first end 201 (adjacent to the first light-incident surface 110 of the plate 100) with a maximum height H1 and a maximum width W1 in the arrangement direction A; The flat portion 220 of the structure 200 connected to the second end 202 (adjacent to the first surface 130 of the board 100) has a maximum height H3 and a maximum width W3 in the arrangement direction A. Since the curvature radius CR of the light-emitting curved surface 203 is the same from the first end 201 to the second end 202, the ratio (H1/W1) of the maximum height H1 to the maximum width W1 where the first gradual portion 210 connects to the first end 201 will be less than The ratio of the maximum height H3 to the maximum width W3 where the flat portion 220 is connected to the second end 202 (H3/W3), and the ratio of the maximum height to the maximum width of the end of the first gradation portion 210 connected to the flat portion 220 (not shown) ) Will be equal to the ratio of the maximum height H3 of the flat portion 220 adjacent to the second end 202 to the maximum width W3.

In this embodiment, the plurality of first ends 201 of the plurality of strip-shaped microstructures 200 are, for example, separated from each other, and the plurality of second ends 202 are, for example, connected to each other, but it is not limited thereto. In another embodiment, the first ends 201 of the plurality of strip-shaped microstructures 200 are separated from each other, for example, and the second ends 202 are separated from each other, for example. In addition, the shape of the strip-shaped microstructure 200 at the second end is, for example, a semi-cylindrical shape, but is not limited thereto.

In the light source module 1 of this embodiment, the maximum height of the first gradation portion 210 of the strip-shaped microstructure 200 of the light guide plate 10 in the first direction B is lower than that adjacent to the first end 201, and the lower the height The light-emitting effect on the side of the light-emitting surface 120 adjacent to the light-incident surface 110 is reduced, and the hot spot phenomenon of uneven brightness is improved; and the maximum height of the first gradation portion 210 in the first direction B is higher than the maximum height of the second end 202, The light-emitting effect can be improved, and the light-emitting surface 120 far away from the light-incident surface 110 (adjacent to the first surface 130 of the board 100) may have insufficient brightness. In other words, since the radius of curvature CR is the same, when the ratio of the maximum height to the maximum width of the strip-shaped microstructure 200 is small, the light-emitting effect of the light guide plate 10 will be reduced; when the maximum height of the strip-shaped microstructure 200 is When the ratio to the maximum width is larger, the light emitting effect of the light guide plate 10 will be improved. Therefore, the overall brightness uniformity of the light emitting surface 120 of the light guide plate 10 can be improved.

Please refer to FIG. 2 again, the plate body 100 of the light guide plate 10 further has a bottom surface 140, and the bottom surface 140 is adjacent to the light incident surface 110 and the first surface 130 and is opposite to the light output surface 120. In order to further enhance the light-emitting effect on the side of the light-emitting surface 120 away from the light-incident surface 110, the bottom surface has, for example, a plurality of diffusing microstructures 141. The distribution density of the diffusing microstructures 141 is, for example, from close to the light incident surface 110 to away from the light incident surface 110. The direction gradually becomes denser. In this embodiment, the diffusing microstructures 141 may be dots or other microstructures that can diffuse the light L1. The distribution density of the plurality of diffusion microstructures 141 can be adjusted according to different design requirements.

4A is a schematic cross-sectional view of the strip-shaped microstructure in the extending direction of an embodiment of the creation. 4B and 4C are other embodiments of the strip-shaped microstructure of the present invention. Referring to FIGS. 4A to 4C, in the strip-shaped microstructure 200 of this embodiment, the maximum height of the first gradient portion 210 gradually increases in a linear manner from the first end 201 to the second end 202, that is, the height of the first gradient portion 210 The light-emitting curved surface 203 is an inclined straight line on the cross-sectional view of FIG. 4A. In addition, the connection between the first gradual portion 210 and the flat portion 220 has an included angle θ1. The strip-shaped microstructure 200 of the present invention can also have other designs. For example, the maximum height of the first gradation portion 210 gradually increases in a non-linear manner from the first end 201 to the second end 202, that is, the light-emitting curved surface 203a of the first gradation portion 210 is an inclined curve, as shown in FIG. 4B. Alternatively, the included angle θ2 at the connection between the first gradual portion 210 and the flat portion 220 is a round chamfer, as shown in FIG. 4C, and the radius of curvature of the round chamfer is, for example, 40 mm, but it is not limited thereto. The above-mentioned different designs can be used independently or in combination, and there is no special restriction on this creation.

5 is a schematic cross-sectional view of a light source module according to another embodiment of the creation. Referring to FIG. 5, the light source module 1a of this embodiment is similar in structure and advantages to the light source module 1 described above. The only difference is that in the light source module 1a of this embodiment, the strip-shaped microstructure 200a on the light guide plate 10a is A gradient portion 210a extends from the first end 201 to the second end 202. Specifically, the strip-shaped microstructure 200a does not have the flat portion 220, and the maximum height of the first gradual portion 210a in the light emitting direction B gradually increases from the first end 201 to the second end 202.

6 is a schematic cross-sectional view of a light source module according to another embodiment of the creation. Please refer to FIG. 6, the light source module 1b of this embodiment is similar in structure and advantages to the light source module 1 described above, and only the main differences of the structure are described below. The light source module 1b of this embodiment also includes a plurality of second light-emitting elements 30. The first surface 130 of the light guide plate 10 of the light source module 1 in FIG. 1 corresponds to the plate of the light guide plate 10b of the light source module 1b in this embodiment. The second light-incident surface 130b of the body 100b, the second light-incident surface 130b is adjacent to the light-emitting surface 120 and opposite to the first light-incident surface 110, and the plurality of second light-emitting elements 30 are arranged opposite to the second light-incident surface 130b and are suitable for The emitted light L2 is incident on the second light incident surface 130b. Each stripe-shaped microstructure 200b also has a second gradation portion 230 connected to the first gradation portion 210 and extending to the second end 202. The maximum height of the second gradation portion 230 in the first direction B is from the second end 202 toward the first One end 201 gradually increases. Specifically, the strip-shaped microstructure 200b does not have a flat portion 220, the second gradient portion 230 has a maximum height H4 where it connects to the second end 202, and the second gradient portion 230 is away from the second end 202 and is connected to the first gradient portion 210 One end of has a maximum height H5, wherein the maximum height H4 is less than the maximum height H5. The maximum height H4 is, for example, 0.1um ~ 2um, and the maximum height H5 is, for example, 5um ~ 20um, but not limited to this.

In this embodiment, the plurality of first ends 201 of the plurality of strip-shaped microstructures 200b are, for example, separated from each other, and the plurality of second ends 202 are also separated from each other, for example. The connection points of the plurality of first ends 201 and the plurality of second ends 202 of the plurality of strip-shaped microstructures 200b may be separated or connected to each other, for example.

Please refer to FIG. 6, when the light is incident on both sides, the middle area of the light guide plate 10b may have insufficient brightness. Therefore, in addition to the configuration of the multiple strip-shaped microstructures 200b described above, in order to correspond to the configuration of the incident light on both sides, The distribution density of the plurality of diffusion microstructures 141 on the bottom surface 140b gradually becomes denser and then gradually becomes sparser from close to the first light incident surface 110 toward a direction away from the first light incident surface 110. The area with the highest distribution density corresponds to the first light incident surface 110. The connection between the gradation portion 210 and the second gradation portion 230 can further enhance the light-emitting effect here.

FIG. 7 is a schematic cross-sectional view of a light source module according to another embodiment of the creation. Please refer to FIG. 7, the light source module 1c of this embodiment is similar to the above-mentioned light source module 1b in structure and advantages. The only difference is that in the light source module 1c of this embodiment, the strip-shaped microstructure 200c on the light guide plate 10c also has The flat portion 220c. The flat portion 220c is connected between the first gradient portion 210c and the second gradient portion 230c, and the maximum height of the flat portion 220c in the first direction B is the same, and the maximum height of the second gradient portion 230c in the first direction B is from The second end 202 gradually increases toward the first end 201. In this embodiment, the length F1 of the first gradation portion 210c of each strip-shaped microstructure 200c in the extension direction E is 1/3 of the length F2 of each strip-shaped microstructure 200c in the extension direction E, and each strip-shaped microstructure 200c The length F3 of the flat portion 220c in the extension direction E is also 1/3 of the length F2 of each strip-shaped microstructure 200c in the extension direction E, and the length F4 of the second gradation portion 230c of each strip-shaped microstructure 200c in the extension direction E It is also 1/3 of the length F2 of each strip-shaped microstructure 200c in the extending direction E, but not limited to this. The lengths F1, F3, F4 can be adjusted according to different design requirements.

The strip-shaped microstructures 200a, 200b, and 200c used in the light source modules 1a, 1b, and 1c can also be gradually increased in a non-linear manner using the maximum height of the gradation as shown in FIG. 4B, or the connection point as shown in FIG. 4C The included angle is round and chamfered design, this creation is not particularly limited. The shape of the strip-shaped microstructures 200a, 200b, and 200c is not limited to a semi-cylindrical shape.

In summary, in the light source module of this creative embodiment, the maximum height of the first gradation portion of the strip-shaped microstructure on the light guide plate in the first direction is lower than that adjacent to the first end. The radius of curvature of the light-emitting surface of the microstructure perpendicular to the extension direction is the same from the first end to the second end. When the height is lower, the ratio of the maximum height to the maximum width becomes smaller, which can reduce the light-emitting surface adjacent to the light-incident surface The light-emitting effect on the side of the light source can improve the hot spot phenomenon of uneven brightness; and the maximum height of the first gradient in the first direction gradually increases from the first end to the second end, so that the maximum height of the strip-shaped microstructure at the second end Higher, when the height is higher, the ratio of the maximum height to the maximum width is greater, which can improve the light output effect and improve the situation that the light output on the side of the light output surface away from the light entrance surface will have insufficient brightness. Therefore, the overall brightness uniformity of the light-emitting surface of the light guide plate can be improved.

However, the above are only the preferred embodiments of this creation, and should not be used to limit the scope of implementation of this creation, that is, simple equivalent changes and modifications made according to the scope of patent application and new description of this creation, All are still within the scope of this creation patent. In addition, any embodiment of this creation or the scope of the patent application does not have to achieve all the purposes or advantages or features disclosed in the creation. In addition, the abstract part and title are only used to assist the search of patent documents, not to limit the scope of rights of this creation. In addition, the terms "first" and "second" mentioned in this specification or the scope of the patent application are only used to name the element (element) or to distinguish different embodiments or ranges, and are not used to limit the number of elements. Upper or lower limit.

1, 1a, 1b, 1c: light source module 10, 10a, 10b, 10c: light guide plate 20: The first light-emitting element 30: second light emitting element 100, 100b: plate body 110: The first light incident surface 120: Glossy Surface 130: first side 130b: The second light incident surface 140: bottom 141: Diffusion Microstructure 200, 200a, 200b, 200c: strip microstructure 201: first end 202: second end 203, 203a: light emitting surface 210, 210a, 210c: the first gradient 220, 220c: flat part 230, 230c: second gradient A: Arrangement direction B: First direction CR: radius of curvature D: spacing E: Extension direction F1, F2, F3, F4: length H1, H2, H3, H4, H5: Maximum height L1, L2: light W1, W3: Maximum width θ1, θ2: included angle

FIG. 1 is a three-dimensional schematic diagram of a light source module according to an embodiment of the creation. Fig. 2 is a schematic cross-sectional view of Fig. 1. 3A is a schematic diagram of a side facing the first light incident surface of the light guide plate of FIG. 1. 3B is a schematic diagram of the side facing the first surface of the light guide plate of FIG. 1. 4A is a schematic cross-sectional view of the strip-shaped microstructure in the extending direction of an embodiment of the creation. 4B and 4C are other embodiments of the strip-shaped microstructure of the present invention. 5 is a schematic cross-sectional view of a light source module according to another embodiment of the creation. 6 is a schematic cross-sectional view of a light source module according to another embodiment of the creation. FIG. 7 is a schematic cross-sectional view of a light source module according to another embodiment of the creation.

1: Light source module

10: Light guide plate

20: The first light-emitting element

100: Board body

110: The first light incident surface

120: Glossy Surface

130: first side

140: bottom

200: Strip microstructure

201: first end

202: second end

203: Light emitting surface

210: The first gradient

220: flat part

A: Arrangement direction

E: Extension direction

F1, F2, F3: length

L1: light

Claims (13)

A light guide plate, including: A board having a light-incident surface and a light-emitting surface, the light-emitting surface is adjacent to the light-incident surface; and A plurality of strip-shaped microstructures are arranged on the light emitting surface, each of the strip-shaped microstructures has a first end and a second end and extends along an extension direction. The first end is close to the light incident surface, and the first end The two ends are far away from the light-incident surface, each of the strip-shaped microstructures has a first gradation portion connected to the first end and the maximum height in a first direction perpendicular to the light-emitting surface is from The first end gradually increases toward the second end, wherein each of the strip-shaped microstructures further has a light-emitting curved surface, and the light-emitting curved surface has a radius of curvature perpendicular to the extending direction from the first end to the second end For the same. The light guide plate according to claim 1, wherein each of the strip-shaped microstructures further has a flat part connected to the first gradation part and extending to the second end, and the flat part is in the first direction The maximum height is the same from one end connected to the first gradual change portion to the second end. The light guide plate according to claim 2, wherein the connection between the first gradation portion and the flat portion is a round chamfer. The light guide plate according to claim 1, wherein each of the strip-shaped microstructures further has a second gradation part connected to the first gradation part and extending to the second end, and the second gradation part is at the first gradation part. The maximum height in one direction gradually increases from the second end toward the first end. The light guide plate according to claim 1, wherein each of the strip-shaped microstructures further has a flat part and a second gradation part, and the flat part is connected between the first gradation part and the second gradation part, The maximum height of the flat portion in the first direction is the same, and the maximum height of the second gradual portion in the first direction gradually increases from the second end toward the first end. The light guide plate according to claim 1, wherein the length of the first gradation portion of each of the strip-shaped microstructures in the extending direction is half of the length of each of the strip-shaped microstructures in the extending direction. The light guide plate according to claim 1, wherein the radius of curvature is 10um ~ 300um. The light guide plate according to claim 1, wherein the strip-shaped microstructures are arranged along an arrangement direction parallel to the light incident surface, and the extension direction is perpendicular to the light incident surface. The light guide plate according to claim 1, wherein the strip-shaped microstructures are arranged on the entire surface of the light emitting surface. The light guide plate according to claim 1, wherein the plate body further has a bottom surface adjacent to the light incident surface and opposite to the light exit surface, the bottom surface has a plurality of diffusion microstructures, and the distribution density of the diffusion microstructures It gradually becomes denser from close to the light incident surface toward the direction away from the light incident surface. The light guide plate according to claim 1, wherein the plate body further has a bottom surface adjacent to the light incident surface and opposite to the light exit surface, the bottom surface has a plurality of diffusion microstructures, and the distribution density of the diffusion microstructures From close to the light-incident surface toward the direction away from the light-incident surface, it gradually becomes denser and then gradually becomes sparser. A light source module includes: A light guide plate, including: A board having a first light-incident surface and a light-emitting surface, the light-emitting surface is adjacent to the first light-incident surface; and A plurality of strip-shaped microstructures are arranged on the light-emitting surface, each of the strip-shaped microstructures has a first end and a second end and extends along an extension direction, the first end is close to the first light-incident surface, The second end is far away from the first light-incident surface, and each of the strip-shaped microstructures has a first gradation portion connected to the first end and in a first direction perpendicular to the light-emitting surface The maximum height of is gradually increased from the first end to the second end, and each of the strip-shaped microstructures has a light-emitting curved surface, and a radius of curvature of the light-emitting curved surface perpendicular to the extending direction is from the first end to The second end is the same; and A plurality of first light emitting elements are arranged opposite to the first light incident surface of the board. The light source module according to claim 12, further comprising a plurality of second light-emitting elements, the board further has a second light-incident surface, adjacent to the light-emitting surface and opposite to the first light-incident surface, The second light-emitting element is disposed opposite to the second light-incident surface, and each of the strip-shaped microstructures further has a second gradation part connected to the first gradation part and extending to the second end. The second gradation part The maximum height in the light emitting direction gradually increases from the second end toward the first end.

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