TWI588553B - Light guide plate and backlight module - Google Patents

Description

Light guide plate and backlight module

The invention relates to a light guiding component, and in particular to a light guiding plate and a backlight module.

The light guide plate has a light incident surface, a light exit surface, and a reflective surface. The light provided by the light source enters the light guide plate from the light incident surface of the light guide plate, and is emitted from the light exit surface of the light guide plate. In order to enable a more uniform mixing of the light source passing through the inside of the light guide plate, a microstructure such as a dot-like microstructure or a strip-shaped microstructure is usually provided on the light-emitting surface or the reflective surface of the light guide plate.

However, generally, the structure of the surface of the point-like microstructure is rough, and the light forms a diffusion after contacting the surface of the structure, so that the direction of the light after the light guide plate is inconsistent and the light energy is not concentrated, thereby causing poor brightness.

Another technique is to provide strip-like microstructures with different extending directions on the light-emitting surface and the reflecting surface of the light guide plate. Such a light guide plate provided with a strip-shaped microstructure has a better brightness effect than a light guide plate having a dot-like structure, but is liable to produce bright and dark lines and affect the optical appearance of the light guide plate.

Therefore, there is a need for a light guide plate to solve the above problems.

Therefore, one aspect of the present invention provides a light guide plate having a omnidirectional structure, which is disposed on the same surface of the light guide plate by crossing the first micro The structure and the second microstructure are capable of simultaneously controlling the light exit angle and optical tendency of the light guide plate, and can achieve a more uniform effect of light mixing and light output. Furthermore, the uniformity of the overall appearance of the light guide plate can be improved by the treatment of roughening or atomizing the first microstructure and the second microstructure surface. In addition, the first microstructure and the second microstructure can be fabricated by using the existing micro-structure process and equipment, and no additional process equipment is required, so that the process cost is not burdened.

According to the above object of the present invention, a light guide plate having a multi-directional structure including a main body, a plurality of first microstructures, and a plurality of second microstructures is proposed. The main body includes a light incident surface, a light exit surface, and a reflective surface. The reflecting surface is opposite to the light emitting surface. The light entrance surface connects the light surface and the reflection surface. The first microstructure is disposed on the light emitting surface or the reflecting surface, and the first microstructures are arranged along the first extending direction. The second microstructure is disposed on the light emitting surface or the reflecting surface, and the second microstructure is aligned along the second extending direction. Wherein, the second microstructure is located on the same plane as the first microstructure and is disposed to cross each other. Moreover, each of the second microstructures has a single strip shape, and the width of each of the second microstructures is gradually reduced from one end near the light incident surface to the other end away from the light incident surface.

According to an embodiment of the invention, the second microstructure described above intercepts each of the first microstructures.

According to another embodiment of the invention, the first extending direction is perpendicular to the second extending direction.

According to still another embodiment of the present invention, each of the first microstructures or each of the second microstructures is a convex portion or a concave portion.

According to still another embodiment of the present invention, when each of the second microstructures is In the case of the convex portion, the height of the convex portion gradually decreases from one end close to the light incident surface to the other end farther from the light incident surface. When each of the second microstructures is a depressed portion, the depth of the depressed portion gradually decreases from one end near the light incident surface to the other end away from the light incident surface.

According to still another embodiment of the present invention, each of the first microstructures has a V-shaped or inverted V-shaped cross-sectional profile, and a first angle is formed between the two surfaces of each of the first microstructures and the light-emitting surface or the reflective surface. And the second angle.

According to still another embodiment of the present invention, the cross-sectional profile of each of the second microstructures is V-shaped, inverted V-shaped, circular-arc or trapezoidal.

According to still another embodiment of the present invention, the spacing between any adjacent ones of the first microstructures is the same, and the spacing between any two adjacent ones of the second microstructures is the same.

According to still another embodiment of the present invention, the spacing between any adjacent ones of the first microstructures is the same, and the spacing between any two adjacent ones of the second microstructures is different.

According to still another embodiment of the present invention, the spacing between any adjacent ones of the first microstructures is different, and the spacing of any two adjacent ones of the second microstructures is the same.

According to still another embodiment of the present invention, the spacing between any two adjacent ones of the first microstructures is different, and the spacing between any two adjacent ones of the second microstructures is different.

According to still another embodiment of the present invention, at least a portion of the surfaces of the first microstructures are matte, textured or rough.

According to still another embodiment of the present invention, at least a portion of the The surfaces of the second microstructures are matte, textured or rough.

100‧‧‧Light guide plate

120‧‧‧ Subject

122‧‧‧Into the glossy surface

124‧‧‧Glossy surface

126‧‧‧reflecting surface

140‧‧‧First microstructure

140a‧‧‧ surface

140b‧‧‧ surface

160‧‧‧Second microstructure

180‧‧‧V-shaped structure

190‧‧‧Light source

200‧‧‧Light guide plate

220‧‧‧ Subject

222‧‧‧ into the glossy surface

224‧‧‧Glossy

226‧‧‧reflecting surface

240‧‧‧First microstructure

260‧‧‧Second microstructure

280‧‧‧V-shaped structure

290‧‧‧Light source

700‧‧‧ Curve

720‧‧‧ Curve

740‧‧‧ Curve

760‧‧‧ Curve

820‧‧‧ Curve

840‧‧‧ Curve

A1‧‧‧ first area

A2‧‧‧Second area

D‧‧‧Deep

D1‧‧‧First extension direction

D2‧‧‧ second extension direction

H‧‧‧ Height

P‧‧‧ spacing

P’‧‧‧ spacing

S1‧‧‧ first edge

S2‧‧‧ second edge

W‧‧‧Width

Α‧‧‧first angle

Β‧‧‧second angle

The above and other objects, features, advantages and embodiments of the present invention will become more <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; Schematic diagram of the light guide plate.

2 is a partial cross-sectional view showing a first microstructure according to a first embodiment of the present invention.

3 is a partial cross-sectional view showing another first microstructure according to the first embodiment of the present invention.

4 is a partial cross-sectional view showing a second microstructure according to a first embodiment of the present invention.

Figure 5 is a partial cross-sectional view showing another second microstructure in accordance with a first embodiment of the present invention.

Figure 6 is a schematic view showing the structure of a light guide plate having a directional structure according to a second embodiment of the present invention.

Fig. 7 is a graph showing light field distributions in accordance with a third embodiment of the present invention and Comparative Example 1, Comparative Example 2, and Comparative Example 3.

Fig. 8 is a graph showing a light field distribution curve according to a third embodiment of the present invention, a comparison 4, and a comparative example 5.

Please refer to FIG. 1 , which is a schematic structural view of a light guide plate with a multi-directional structure according to a first embodiment of the present invention. This embodiment The light guide plate 100 can be applied to a backlight module (not shown). The light guide plate 100 can include a body 120 and a plurality of microstructures, wherein the plurality of microstructures can include, for example, a plurality of first microstructures 140 and a plurality of second microstructures 160. Through the first microstructures 140 and the second microstructures 160 disposed on the main body 120, the light exiting angle and optical tendency of the light entering the light guide plate 100 can be simultaneously changed and adjusted.

In the light guide plate 100, the main body 120 may be a light transmissive plate or other equivalent light transmissive member. The body 120 mainly includes a light incident surface 122 and at least one main surface, wherein the at least one main surface may include, for example, a light exit surface 124 and a reflective surface 126. The major surface has a first end edge S1 and a second end edge S2 that are paired and parallel to each other. In this embodiment, the first end edge S1 is the edge where the main surface is connected to the light incident surface 122, and the second end edge S2 is away from the edge of the light incident surface 122. The reflecting surface 126 and the light emitting surface 124 are respectively located on opposite sides of the main body 120. In addition, the light-incident surface 122 is connected to the light-emitting surface 124 and the reflective surface 126. That is, the opposite sides of the light-incident surface 122 are respectively connected to one side of the light-emitting surface 124 and one side of the reflective surface 126. The light source 190 is disposed beside the light incident surface 122, and the light generated by the light source 190 can enter the light guide plate 100 through the light incident surface 122. The first microstructure 140 is on the same plane as the second microstructure 160. That is, the first microstructures 140 and the second microstructures 160 are disposed on the light-emitting surface 124 or on the reflective surface 126 at the same time. In other embodiments, the first microstructure 140 and the second microstructure 160 may be disposed on both the light-emitting surface 124 and the reflective surface 126. Moreover, the first microstructures 140 and the second microstructures 160 on the same side are disposed to cross each other. In an embodiment, a second microstructure 160 can intercept each of the first microstructures 140. In other words, as in the first As shown in FIG. 1, the first microstructure 140 is tangent to the periphery of the second microstructure 160.

As shown in FIG. 1, all of the first microstructures 140 are arranged on the light-emitting surface 124 along the first extending direction D1, and are arranged from the first end edge S1 to the second end edge S2. On the other hand, all of the second microstructures 160 are arranged on the light exit surface 124 along the second extension direction D2, and the second microstructures 160 extend from the first end edge S1 to the second end edge S2. Each of the second microstructures 160 may have a single strip shape. Moreover, the width of each of the second microstructures 160 is gradually reduced from an end near the light incident surface 122 toward a direction away from the light incident surface 122. Since the first microstructures 140 and the second microstructures 160 on the same surface are disposed to cross each other, the second extending direction D2 is different from the first extending direction D1. That is, as shown in FIG. 1, the area where the first microstructure 140 is located is the first area A1, the area where the second microstructure 160 is located is the second area A2, and the second area A2 is adjacent to the first area. Area A1. Moreover, since the second microstructures 160 are disposed to intersect with the first microstructures 140, and the width of each of the second microstructures 160 is gradually reduced from an end near the light incident surface 122 to a direction away from the light incident surface 122, As can be seen from FIG. 1, the first area A1 and the second area A2 are adjacently arranged along a first direction (that is, the second extending direction D2), and the boundary of the first area A1 or the second area A2 is close to One end of the light incident surface 122 faces away from the other end of the light incident surface 122 to change in a second direction different from the first direction (that is, the first extending direction D1). The boundary between the first area A1 and the second area A2 is exemplified by a width. Preferably, each of the first areas A1 has a width from an end close to the light incident surface 122 to another distance away from the light incident surface 122. One end gradually increases, and the width of each second area A2 is from One end of the near-into-light surface 122 is gradually reduced to the other end away from the light-incident surface 122. In an embodiment, the first extending direction D1 is perpendicular to the second extending direction D2, but is not limited thereto. For the sake of clarity, the first embodiment is illustrated by the embodiment in which the first microstructure 140 and the second microstructure 160 are simultaneously disposed on the light-emitting surface 124, and is not intended to limit the present invention. The first microstructure 140 and the second microstructure 160 may also be disposed on the reflective surface 126 at the same time.

Please refer to FIG. 1 and FIG. 2 together. FIG. 2 is a partial cross-sectional view showing a first microstructure according to a first embodiment of the present invention. In an embodiment, each of the first microstructures 140 may be a convex portion protruding from the light-emitting surface 124, and each of the first microstructures 140 has an inverted V-shaped cross-sectional profile. Moreover, each of the first microstructures 140 has two surfaces 140a and 140b that are coupled to the light exit surface 124. A first angle α and a second angle β are formed between the two surfaces 140a and 140b and the light-emitting surface 124, respectively. The angle between the first angle α and the second angle β can be designed according to the angle of the light entering the light guide plate 100, thereby changing the light exit angle of the light entering the light guide plate 100, thereby improving the luminous flux of the whole light guide plate 100 and Brightness value. At the same time, the shape of each of the first microstructures 140 changes according to the angle between the first angle α and the second angle β, and the vertical height of the top end of each of the first microstructures 140 and the light exit surface 124 is also Changed. In an embodiment, the reflective surface 126 may be additionally provided with a V-shaped structure 180 or other microstructures having similar functions.

Please refer to FIG. 2 and FIG. 3 simultaneously. FIG. 3 is a partial cross-sectional view showing another first microstructure according to the first embodiment of the present invention. In the embodiment of Figure 2, the first microstructures 140 are arranged in a continuous manner. Columns, and these first microstructures 140 are directly connected to each other. In the embodiment of FIG. 3, the first microstructures 140 are arranged in a discontinuous manner, and each of the first microstructures 140 is not connected to each other. To be apparent, the first microstructures 140 may be arranged on the exit surface 124 or the reflective surface 126 in a continuous, discontinuous or partially continuous and partially discontinuous manner. Moreover, the spacing P between any two adjacent first microstructures 140 may be the same or different. By adjusting the spacing P between the adjacent two first microstructures 140 to adjust the density of the first microstructure arrangement, the brightness and luminous flux of the light guide plate 100 can also be changed, thereby improving the light uniformity of the light guide plate 100. .

Referring to FIG. 1 and FIG. 4 together, FIG. 4 is a partial cross-sectional view showing a second microstructure according to the first embodiment of the present invention. In this embodiment, the second microstructure 160 may be a recessed portion recessed into the light exit surface 124, and the second microstructure 160 has a circular arc shape. Moreover, each of the second microstructures 160 is located on the light exit surface 124, and extends all of the first microstructures 140 along the first extending direction D1. In one embodiment, the depth D of the second microstructure 160 is gradually reduced from the end close to the light incident surface 122 toward the light incident surface 122. In an example, the distance between the first microstructures 140 remaining after being truncated and the first microstructures 140 remaining after being truncated can be changed by adjusting the depth D and the width W of the second microstructure 160. length. Therefore, by changing the depth D and the width W of the second microstructure 160, the optical tendency of the light guide plate 100 can be changed.

Please refer to FIG. 5, which is a partial cross-sectional view showing another second microstructure according to the first embodiment of the present invention. In the present embodiment, the cross-sectional profile of the second microstructure 160 is trapezoidal. In an example, the second microstructure The profile of 160 may be V-shaped. In some examples, the cross-sectional profile of the second microstructure 160 can be contoured, for example, by R-knife, V-knife, flat knife, or poly-knife. Different cross-sectional contour shapes can cause the light guide plate 100 to produce different light collecting effects.

It is to be understood that the second microstructures 160 shown in Figures 4 and 5 are not interconnected to each other, but in other embodiments, the second microstructures 160 may also be interconnected to each other in a continuous manner. . Moreover, the spacing P' between any two adjacent second microstructures 160 may be the same or different. The degree of density of the arrangement of the second microstructures 160 is adjusted by adjusting the pitch P' between the adjacent two second microstructures 160, thereby improving the light guiding function of the light guide plate 100.

Please refer to FIG. 6 , which is a structural diagram of a light guide plate with a directional structure according to a second embodiment of the present invention. The light guide plate 200 of the present embodiment may also include a body 220 and a plurality of microstructures, wherein the plurality of microstructures may include, for example, a plurality of first microstructures 240 and a plurality of second microstructures 260. The body 220 includes a light incident surface 222 and at least one major surface, wherein the at least one major surface may include, for example, a light exit surface 224 and a reflective surface 226. The major surface has a first end edge S1 and a second end edge S2 that are paired and parallel to each other. In this embodiment, the first end edge S1 is the edge where the main surface is connected to the light incident surface 222, and the second end edge S2 is away from the edge of the light incident surface 222. The light source 290 is disposed beside the light incident surface 222, and the light generated by the light source 290 can enter the light guide plate 200 through the light incident surface 222. The first microstructure 240 and the second microstructure 260 are convex portions protruding from the light exit surface 224 . The cross-sectional profiles of the first microstructure 240 and the second microstructure 260 are respectively It is inverted V and round. The first microstructures 240 are arranged on the light-emitting surface 224 along the first extending direction D1 and are arranged from the first edge S1 to the second edge S2. All of the second microstructures 260 are arranged on the light exit surface 224 along the second extension direction D2, and the second microstructures 260 extend from the first end edge S1 to the second end edge S2. The second microstructure 260 intersects each of the first microstructures 240 to intercept the first microstructure 240. Similarly, as shown in FIG. 6, the area where the first microstructure 240 is located is the first area A1, the area where the second microstructure 260 is located is the second area A2, and the second area A2 is adjacent to the first area. A1. Moreover, since the second microstructures 260 are disposed to intersect with the first microstructures 240, and the width of each of the second microstructures 260 is gradually reduced from the end near the light incident surface 222 toward the light incident surface 222, As can be seen from FIG. 3, the width of each of the first regions A1 gradually increases from one end close to the light incident surface 222 to the other end away from the light incident surface 222, and the width of each second region A2 is from close to the entrance. One end of the smooth surface 222 is gradually reduced to the other end away from the light incident surface 222. Each of the second microstructures 260 can also be in a single strip shape. Moreover, the width W of each of the second microstructures 260 is gradually reduced from an end close to the light incident surface 222 toward a direction away from the light incident surface 222. In another embodiment, the height H of the second microstructure 260 is gradually reduced from the end close to the light incident surface 222 toward the light incident surface 222.

In an embodiment, the distance between each of the first microstructures 240 remaining after being truncated and the first remaining after being truncated can also be changed by adjusting the height H and the width W of the second microstructure 260. The length of the microstructure 240. Therefore, by changing the height H and width of the second microstructure 260 W, the optical tendency of the light guide plate 200 can be changed. In an embodiment, the reflective surface 226 may be additionally provided with a V-shaped structure 280 or other microstructure having similar functions.

The following is compared with a conventional light guide plate in the third embodiment. Referring to Fig. 7, there is shown a light field distribution graph of a third embodiment of the present invention, a comparative example 1, a comparative example 2, and a comparative example 3. In the third embodiment, the V-shaped structure is disposed on the light-emitting surface of the light guide plate, and the first microstructure and the second microstructure are disposed on the reflective surface. The comparative example 1 is a light guide plate having a dot-like structure on one side, and the comparative example 2 is A light guide plate having a V-shaped structure and a dot-shaped structure on the light-emitting surface is provided, and Comparative Example 3 is a light guide plate having a V-shaped structure in which the light-emitting surface and the reflection surface are respectively provided with different extending directions. As can be seen from Fig. 7, the thickest curve 700 in the figure is a curve obtained by the simulation experimental data of the light guide plate according to the third embodiment, and the curve obtained from the simulation experimental data according to the comparative examples 1, 2 and 3 is obtained. 720, 740 and 760 are smooth. This means that the first microstructure and the second microstructure disposed through the crossover can effectively control the light field distribution angle. The irregularities of the curves 720, 740, and 760 of Comparative Example 1-3 represent the noise of the light energy loss, which indicates that the control effect on the light field distribution angle is poor.

Please refer to Table 1 below, which compares the light guides of the third embodiment, the comparative example 1, the comparative example 2, and the comparative example 3 with three optical films and four optical films, respectively. . As can be seen from Table 1, the design of the light guide plate of the V-shaped structure in which the light-emitting surface and the reflection surface are provided with different extending directions in Comparative Example 3 is helpful for enhancing the luminance. However, the light guide plate structure design of Comparative Example 3 causes the light guide plate and the optical film to be adsorbed and bright and dark. problem. On the contrary, the light guide plate of the third embodiment has the first microstructure and the second microstructure on the reflective surface, and can better overcome the above problems of the light guide plate and the optical film adsorption and bright and dark lines. Brightness effect.

Referring to FIG. 8, there is shown a light field distribution graph according to a third embodiment of the present invention, a comparison 4, and a comparative example 5. In Comparative Example 4, a light guide plate having a V-shaped structure on the light-emitting surface and a sandblasted structure on the reflection surface, and a light guide plate in which a vertical V-shaped structure is provided on the light-emitting surface and a microlens is provided on the reflection surface is used. As can be seen from FIG. 8, the thickest curve 700 in the figure is a curve obtained according to the simulation experimental data of the light guide plate of the third embodiment, and the curve 820 obtained by comparing the simulation data according to the comparative examples 4 and 5 and 840 smooth. This means that the first microstructure and the second microstructure disposed through the crossover can effectively control the light field distribution angle. The other irregularities of the curves 820 and 840 represent the noise of the light energy loss, which means that the control effect on the light field distribution angle is poor.

Please refer to Table 2 below, which is a comparison table of luminances obtained by aligning the light guide plates of the third embodiment, the comparative example 4, and the comparative example 5 with a single turning film. As can be seen from Table 2, the third implementer The luminance effect produced by the light guide plate of the type is remarkably better than that of Comparative Example 4 and Comparative Example 5.

In some embodiments, the first microstructures 140 and 240, except for the first microstructures 140 and 240 and the second microstructures 160 and 260 of the light guide plates 100 and 200, respectively, can cause the light guide plate to adjust the light angle and optical tendency. Or the surface of the second microstructures 160 and 260 may be processed into a matte, textured or rough surface by sandblasting or laser to enhance the adjustment of the first microstructures 140 and 240 and the second microstructures 160 and 260. Light effect.

According to the embodiment of the present invention, the advantages of the present invention are mainly to generate a function of simultaneously controlling the light exit angle and optical tendency of the light guide plate through the first microstructure and the second microstructure disposed on the same surface of the light guide plate. It can achieve a more uniform effect of mixing and light. Furthermore, the uniformity of the overall appearance of the light guide plate can be improved by the treatment of roughening or atomizing the first microstructure and the second microstructure surface. In addition, the first microstructure and the second microstructure can be fabricated by using the existing micro-structure process and equipment, and no additional process equipment is required, so that the process cost is not burdened.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and the present invention can be modified and modified without departing from the spirit and scope of the present invention. The scope is subject to the definition of the scope of the patent application attached.

100‧‧‧Light guide plate

120‧‧‧ Subject

122‧‧‧Into the glossy surface

124‧‧‧Glossy surface

126‧‧‧reflecting surface

140‧‧‧First microstructure

160‧‧‧Second microstructure

180‧‧‧V-shaped structure

190‧‧‧Light source

A1‧‧‧ first area

A2‧‧‧Second area

D1‧‧‧First extension direction

D2‧‧‧ second extension direction

S1‧‧‧ first edge

S2‧‧‧ second edge

Claims (19)

A light guide plate comprising: a main body, comprising: a light incident surface; and at least one main surface connecting the light incident surface, the main surface having a first end edge and a second end edge which are paired and parallel to each other At least one first region; at least one second region adjacent to the at least one first region, and the at least one first region and the at least one second region are located on the same at least one major surface; and wherein The at least one first region and at least a portion of the at least one second region are provided with a plurality of microstructures, and the microstructures located in the at least one first region are tangent to the at least one second region The microstructures of the at least one first region are arranged along a first extending direction and are arranged from the first end edge of the main surface to the second end edge; wherein the at least one is located The microstructures of the second region are aligned along a second direction of extension and extend from the first end edge of the major surface to the second end edge. The light guide plate of claim 1, wherein the microstructures comprise a plurality of first microstructures, the at least one first region is provided with the first microstructures, and the first microstructures are along The first extending direction is arranged. The light guide plate of claim 2, wherein the first micro The structure is a continuous arrangement without spaces. The light guide plate of claim 2, wherein the microstructures further comprise a plurality of second microstructures, the at least one second region is provided with a single second microstructure, and the second microstructures are Arranged along the second extending direction, and the first extending direction and the second extending direction intersect each other. The light guide plate of claim 4, wherein each of the second microstructures intercepts each of the first microstructures. The light guide plate of claim 4, wherein the first extending direction is perpendicular to the second extending direction. The light guide plate of claim 4, wherein each of the first microstructures or each of the second microstructures is a convex portion or a concave portion. The light guide plate of claim 7, wherein when each of the second microstructures is the convex portion, the height of the convex portion is from the end close to the light incident surface to away from the light entering The other end of the face is gradually reduced, wherein when each of the second microstructures is the recess, the depth of the recess is gradually from the end near the light incident surface to the other end away from the light incident surface Zoom out. The light guide plate of claim 4, wherein each of the first microstructures has a V-shaped or inverted V-shaped cross-sectional profile, and two surfaces of each of the first microstructures and the at least one major surface A first angle and a second angle are formed between each other. The light guide plate of claim 4, wherein each of the second microstructures has a V-shaped, inverted V-shaped, circular arc-shaped or trapezoidal profile. The light guide plate of claim 4, wherein the spacing between any two of the first microstructures is the same, and the spacing between any two of the second microstructures is the same. The light guide plate of claim 4, wherein the spacing between any two of the first microstructures is the same, and the spacing between any two of the second microstructures is different. The light guide plate of claim 4, wherein the spacing between any two of the first microstructures is different, and the spacing between any two of the second microstructures is the same. The light guide plate of claim 4, wherein the spacing between any two of the first microstructures is different, and the spacing between any two of the second microstructures is different. The light guide plate of claim 4, wherein at least a portion of the surfaces of the first microstructures are matte, textured or rough. The light guide plate of claim 4, wherein at least a portion of the surfaces of the second microstructures are matte, textured or rough. The light guide plate of claim 1, wherein the boundary of the at least one first region or the at least one second region changes from an end close to the light incident surface toward the other end away from the light incident surface. The light guide plate of claim 17, wherein the at least one first area and the at least one second area are adjacently arranged along a first direction, the at least one first area or the at least one second area The boundary is from an end close to the light incident surface toward the other end away from the light incident surface to change along a second direction different from the first direction. A backlight module comprising: a light guide plate according to any one of claims 1 to 18; and a light source disposed beside the light incident surface of the light guide plate.