TWI464464B - Backlight module and light guide plate - Google Patents

Description

Backlight module and light guide plate

The present invention relates to an optical module and an optical component, and more particularly to a backlight module and a light guide plate.

In recent years, with the maturity of display technology and lighting technology, various types of display devices and illumination devices such as liquid crystal displays (LCDs) and planar light sources have matured and are widely used in people's daily life. In order to meet consumer demand for large display devices or a wide range of uniform planar light sources, a wide variety of light guides and backlight modules are designed to meet large size applications.

In general, based on economic considerations, in order to save manufacturing costs and volumetric weight, side-lit lighting is often used. However, in the edge-lit backlight module, since the light-emitting elements are disposed on the side of the light guide plate, the light emitted from the light-emitting elements from the side of the light guide plate is guided to the center of the light guide plate by the light guide plate. As a result, it is easy to cause a high luminance around the light guide plate and a low luminance in the central region, which affects the display quality.

Wherein, if the brightness of the light-emitting element is increased in an attempt to improve the center of the light guide plate In the case where the luminance of the region is low, the luminance in the surrounding region of the light guide plate near the light incident surface is significantly too high. In order to block these areas of excessive brightness, the width of the front bezel is also increased, which causes the viewable display area to shrink. Therefore, how to improve the uniformity of the light output of the backlight module without sacrificing the size of the display screen is an urgent problem to be solved.

In addition, the Republic of China Patent Publication No. 201209480 discloses a backlight module structure having a first curved convex surface and a second curved convex surface. The Republic of China Patent Publication No. M292707 discloses a light-guide plate entrance surface structure having a plurality of dimming structures that can destroy a light traveling path, wherein each dimming structure can effectively adjust a darker or brighter area of the light source according to different light sources. To improve the brightness and uniformity. The Republic of China Patent Publication No. 201039022 discloses a light guide plate structure having two inclined surfaces, which can reduce the light in the non-visible area, that is, the light guide plate is formed and a bright spot is formed, and the light can be transmitted toward the visible area of the light guide plate, thereby It can improve the efficiency of light extraction.

The invention provides a backlight module, which can improve light uniformity.

The present invention provides a light guide plate having a chamfered surface to increase the uniformity of light guide.

Other objects and advantages of the present invention will become apparent from the technical features disclosed herein.

To achieve one or a part or all of the above or other purposes, an embodiment of the present invention provides a backlight module including a light guide plate and at least one light emitting unit. The light guide plate includes a first surface, a second surface, a light incident surface and a first chamfered surface. The second surface is opposite the first surface. The light incident surface connects the first surface and the second surface. The chamfered surface connects the first surface to the light incident surface. The light emitting unit is disposed adjacent to the light incident surface, wherein the light emitting unit has a light emitting surface with respect to the light incident surface, and the width of the light emitting surface in a direction perpendicular to the first surface is D, and the first chamfered surface has a circular arc reference surface, and the circle The arc reference plane is a circular arc line cut by a reference plane perpendicular to the first surface and perpendicular to the light incident surface, and the circular arc has a radius of curvature R, and the first chamfered surface is perpendicular to the incident light. The length in the direction of the surface is L, the thickness of the light guide plate in the direction perpendicular to the first surface is H, and the backlight module satisfies the following formula:

In an embodiment of the invention, the backlight module further includes a plurality of strip-shaped optical microstructures disposed on the light-incident surface, wherein each of the strip-shaped optical microstructures extends in a direction substantially perpendicular to the first surface, and The strip-shaped optical microstructures are arranged in a direction substantially parallel to the first surface.

In an embodiment of the invention, the first chamfered surface is a circular arc surface.

In an embodiment of the invention, the first chamfered surface comprises a plurality of planes that are joined to each other in a meandering manner.

In an embodiment of the invention, the planes that are bent to meet each other are inscribed planes of the arc reference plane.

In an embodiment of the invention, the above-mentioned planes that are bent to meet each other It is the circumscribed plane of the arc reference plane.

In an embodiment of the invention, the light guide plate further includes a second chamfered surface, and the second chamfered surface connects the second surface and the light incident surface.

In an embodiment of the invention, the second chamfered surface has a circular arc reference surface, and a circular reference plane is cut by a reference plane perpendicular to the first surface and perpendicular to the light incident surface. a circular arc line, the radius of curvature of the circular arc line is R, the length of the second chamfered surface in a direction perpendicular to the light incident surface is L, and the thickness of the light guide plate in a direction perpendicular to the first surface is H, and The backlight module satisfies the following formula:

In an embodiment of the invention, the backlight module further includes a reflective unit disposed adjacent to the second surface, wherein the second surface is located between the first surface and the reflective unit.

In an embodiment of the invention, the backlight module further includes a reflective unit disposed adjacent to the first surface, wherein the first surface is located between the second surface and the reflective unit. In an embodiment of the invention, the at least one chamfered surface comprises a first chamfered surface and a second chamfered surface, the first chamfered surface connecting the first surface and the light incident surface, and the second chamfered surface Connecting the second surface and the light incident surface, the first chamfered surface is located between the center of curvature of the second chamfered surface and the second chamfered surface, and the second chamfered surface is located at the center of curvature of the first chamfered surface and the first Chamfer between the surfaces.

An embodiment of the present invention provides a light guide plate for guiding a light beam emitted by a light source. The light source has a light emitting surface, and the light guide plate includes a first surface, a second surface, a light incident surface, and at least one A chamfered surface. The second surface is opposite the first surface. The light incident surface connects the first surface and the second surface. The first chamfered surface connects the first surface to the light incident surface. a light emitting surface of the light source is opposite to the light incident surface, and a width of the light emitting surface in a direction perpendicular to the first surface is D, wherein the first chamfered surface has a circular arc reference surface, and the circular arc reference surface is perpendicular to the light a section of the first surface and perpendicular to a reference plane of the light incident surface is a circular arc line having a radius of curvature R, and the first chamfered surface is perpendicular to the light incident surface. The length is L, the thickness of the light guide plate in the direction perpendicular to the first surface is H, and the light guide plate satisfies the following formula:

Based on the above, the backlight module of the embodiment of the present invention can uniformly distribute the light concentrated on the light incident surface to the region where the light guide plate is far away from the light incident surface by the light guide plate having the chamfered surface, thereby avoiding excessive concentration of the light source. The light-emitting uniformity of the light guide plate can be increased on the incident surface.

The above described features and advantages of the present invention will be more apparent from the following description.

100‧‧‧Backlight module

110,110’‧‧‧Light guide plate

120‧‧‧Lighting unit

B‧‧‧beam

C1, C2‧‧‧ Curvature Center

D‧‧‧Width

H‧‧‧thickness

I‧‧‧First fold line

I’‧‧‧ second fold line

IL‧‧‧ luminous surface

L‧‧‧ length

M‧‧‧ optical microstructure

MS‧‧‧ strip optical microstructure

MSV‧‧‧ strip microstructure

P‧‧‧ plane

PI‧‧‧Inscribed plane

PE‧‧‧External plane

R‧‧‧ radius of curvature

RF‧‧‧reflection unit

RL‧‧ reference line

RP‧‧‧ arc reference surface

RS‧‧‧ reference plane

S1‧‧‧ first surface

S2‧‧‧ second surface

SA1‧‧‧ first chamfered surface

SA2‧‧‧Second chamfered surface

SI‧‧‧Into the glossy surface

S’‧‧‧dotted section

T‧‧‧cut plane

Θ‧‧‧incident angle

1A is a side view of a backlight module in an embodiment of the present invention.

1B is a top view of a backlight module in accordance with the embodiment of FIG. 1A.

1C is an enlarged schematic view of a light guide plate in accordance with the embodiment of FIG. 1A.

2A is a diagram showing the intensity and position distribution of the backlight module in the light guide plate according to the embodiment of FIG. 1.

2B is a graph showing the intensity and position distribution of light in the light guide plate of the control group of FIG. 2A.

2C is a line graph of the relationship between light intensity and position measured along the reference line RL in FIGS. 2A and 2B.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only directions referring to the additional drawings. Therefore, the directional terminology used is for the purpose of illustration and not limitation.

1A is a side view of a backlight module in an embodiment of the present invention, and FIG. 1B is a top view of the backlight module in accordance with the embodiment of FIG. 1A. Referring to FIG. 1A and FIG. 1B , in the embodiment, the backlight module 100 includes a light guide plate 110 and at least one light emitting unit 120 . The light guide plate 110 includes a first surface S1, a second surface S2, a light incident surface SI, and at least a first chamfered surface SA1. The second surface S2 is opposite to the first surface S1. The light incident surface SI connects the first surface S1 and the second surface S2. The light emitting unit 120 is disposed beside the light incident surface SI, and is adapted to emit the light beam B toward the light incident surface SI with the light emitting surface IL. Wherein, if the light beam B is incident on the light guide plate 110 at a large incident angle θ (in the present embodiment, the incident angle θ is an angle between the beam B and the normal vector of the light-emitting surface IL), the first chamfered surface SA1 may be correspondingly The light beams B incident at a larger incident angle θ are reflected to a region of the light guide plate 110 farther from the light emitting unit 120, and can be avoided or The light loss caused by the light beam B having a large incident angle θ directly passing through the light guide plate 110 is reduced, and the light exiting region of the light guide plate 110 is prevented from being concentrated on the side of the light emitting element 120, and the light output of the light guide plate 110 can be further improved. degree.

In detail, the first chamfered surface SA1 connects the first surface S1 and the light incident surface SI, and the second chamfered surface SA2 connects the second surface S2 and the light incident surface SI. The light guide plate 110 may be configured with a first chamfered surface SA1 or a second chamfered surface SA2 on only one side (such as the first surface S1 or the second surface S2), and the other side may be, for example, as indicated by a broken line segment S' The vertical corners of the vertical surface, or the first chamfered surface SA1 and the second chamfered surface SA2 may be disposed on the first surface S1 and the second surface S2 simultaneously adjacent to the light incident surface SI, and have similar effects, the present invention Not limited to this.

For example, in this embodiment, as shown in FIG. 1A, the first chamfered surface SA1 connects the first surface S1 and the light incident surface SI, and the second chamfered surface SA2 connects the second surface S2 and the light incident surface SI. . In the present embodiment, the first chamfered surface SA1 is located between the center of curvature C2 of the second chamfered surface SA2 and the second chamfered surface SA2, and the second chamfered surface SA2 is located at the center of curvature of the first chamfered surface SA1. C1 is between the first chamfered surface SA1. The radius of curvature of the first chamfered surface SA1 and the second chamfered surface SA2 may be the same or different, and the invention is not limited thereto.

In more detail, the width of the light emitting surface IL of the light emitting unit 120 in the direction perpendicular to the first surface S1 is D, the first chamfered surface SA1 has a circular arc reference surface RP, and the circular arc reference surface RP is perpendicular to A section of the first surface S1 and a reference plane RS of the vertical incident surface SI is a circular arc line, the radius of curvature of the circular arc is R, and the first chamfered surface SA1 is perpendicular to the incident surface SI. The length in the direction is L, the thickness of the light guide plate 110 in the direction perpendicular to the first surface S1 is H, and the backlight module 100 satisfies the following formula: Thereby, according to the size of the actual light guide plate 110, the radius of curvature R of the first chamfered surface SA1 at each position on the light guide plate 110 and the length extended by the first chamfered surface SA1 can be designed to meet various applications. demand. The magnitude of the radius of curvature R of the second chamfered surface SA2 at each position on the light guide plate 110 and the length of the second chamfered surface SA2 can also be calculated using the above formula, and thus will not be described again.

1C is an enlarged schematic view of a light guide plate according to the embodiment of FIG. 1A. Referring to FIG. 1A to FIG. 1C, in the embodiment, as shown in FIG. 1A, the first chamfered surface SA1 may be a circular arc surface. For example, it is part of a cylindrical surface. Alternatively, the first chamfered surface SA1 may include a plurality of planes P that are bent to meet. For example, the planes P that are bent to meet each other are the inscribed plane PI of the arc reference plane RP. Or, the plane P that meets in a meandering manner is an circumscribed plane PE of the circular arc reference plane RP, and may have an effect similar to that of the first chamfered surface SA1. Further, the greater the number of these bending planes of the inscribed plane PI or the circumscribed plane PE, the closer to the arc reference plane RP. However, it should be noted that, in this embodiment, the number and length of the bending planes of the inscribed plane PI and the circumscribed plane PE are only used to illustrate the embodiment, and the invention is not limited thereto. In another embodiment of the present invention, the second chamfered surface SA2 may be a circular arc surface or a plurality of planes P that are connected to each other. The invention is not limited thereto.

2A is a diagram showing the intensity and position distribution of the light of the backlight module in the light guide plate according to the embodiment of FIG. 1 , and FIG. 2B is a diagram showing the intensity and position distribution of the light of the control group of FIG. 2A in the light guide plate, please refer to FIG. 2A . 2B, in the present embodiment, the backlight module 100 has, for example, three light emitting units 120 and is arranged to emit light toward the light incident surface SI, wherein the intensity and position distribution of the light in the light guide plate is as shown in FIG. 2A. 2B represents a light intensity and position distribution map in the light guide plate 110' where the first chamfered surface SA1 and the second chamfered surface SA2 are not disposed. Comparing FIG. 2A with FIG. 2B, it can be clearly seen that the light in FIG. 2B is concentrated on the side of the light incident surface SI, and there is a hot spot phenomenon in which the brightness is uneven, and the light guide plate 110' is farther away from the light emitting unit 120. The light in the area has a significant decrease in strength and uneven strength. In Fig. 2A, the hot spot phenomenon can be effectively improved. Moreover, the light intensity and uniformity in the vicinity of the central region of the light guide plate 110 are also significantly improved. In other words, the light guide plate 110 having the first chamfered surface SA1 and the second chamfered surface SA2 can surely improve the uniformity of light emission and the intensity distribution, so that the light-emitting quality and light-emitting efficiency of the light guide plate 110 are improved. Moreover, it can be clearly observed from FIGS. 2A and 2B that the area of the light-exposed area in FIG. 2A is larger than the area in which the light-emitting direction is more uniform in FIG. 2B, and the light intensity in FIG. 2B is excessively concentrated near the light-incident surface SI. The area where the light is uniform is reduced. In other words, in the case of arranging the same power and quantity of the light emitting unit 120, the light guide plate 110 having the first chamfered surface SA1 and the second chamfered surface SA2 may have a shorter uniform light mixing distance, that is, the light is incident on the light. After the surface SI enters the light guide plate 110, it can be uniformly dispersed without excessive concentration after being transmitted for a short distance. On the other hand, the light guide plate 110 having no first chamfered surface SA1 and second chamfered surface SA2 has a long uniform light mixing distance, that is, light. After the light-incident surface SI enters the light guide plate 110, it is transmitted for a long distance and then dispersed more uniformly. In general, in order to avoid light that is not uniformly mixed, a bezel is used to mask the area where the uneven mixing is completed. For the light guide plate 110', since the uniform light mixing distance is long, the frame needs to be wide, but in this way, the area (or the viewable range) in which the light guide plate 110' is not covered by the frame is reduced. On the other hand, since the uniform light-mixing distance of the light guide plate 110 having the first chamfered surface SA1 and the second chamfered surface SA2 is short, the required frame can be reduced and a large visible range can be obtained. In addition, since the uniform light mixing distance of the light guide plate 110 is short, it is also possible to match various color light emitting units (such as red light, blue light, and green light) to match the mixed light dimming, and evenly emit white light or other. Kind of light. Furthermore, the light guide plate 110 may be configured with a first chamfered surface SA1 or a second chamfered surface SA2 on only one side (such as the first surface S1 or the second surface S2), and the other side is configured with a dotted line such as FIG. 1A. The vertical corners depicted by the segment S' can have similar effects, and the invention is not limited thereto.

Further, FIG. 2C is a line graph of the relationship between the light intensity and the position measured along the reference line RL in FIGS. 2A and 2B, please refer to FIG. 2A to FIG. 2C, wherein the first broken line I represents the along the FIG. 2A. The fold line of the relationship between the light intensity measured by the reference line RL and the position, and the second fold line I' represents a line of the relationship between the light intensity measured along the reference line RL in FIG. 2B and the position. Comparing the first fold line I with the second fold line I', it can be found that the difference between the maximum intensity and the minimum intensity in the second fold line I' is much larger than the difference between the maximum intensity and the minimum intensity in the first fold line I. In other words, the light intensity distribution of the first fold line I is relatively uniform compared to the second fold line I' without causing a significant hot spot phenomenon to affect the light quality. Further, Table 1 shows data of hot spot level and hot spot improvement of the light guide plate 110 and the light guide plate 110' in FIGS. 2A and 2B. Please refer to Table 1 as follows: The uniformity of the light intensity of the light guide plate is the ratio of the minimum light intensity in the display area divided by the maximum light intensity, and the hot spot level is the uniformity of the light guide plate to be calculated divided by the light guide plate 110 ′. The percentage obtained by the uniformity. The light guide plate 110 has a lower hot spot level, that is, the light intensity distribution is relatively uniform. Moreover, the hot spot improvement evaluation value (ie, the difference between the hot spot level of the light guide plate 110' and the light guide plate 110) is also improved. In other words, the light guide plate 110 can improve the hot spot phenomenon by the first chamfered surface SA1 and the second chamfered surface SA2. , in turn, the uniformity of the light is increased.

Further, please refer to FIG. 1A and FIG. 1B again. In this embodiment, the backlight module 100 can further include a plurality of strip-shaped optical microstructures MS disposed on the light-incident surface SI, wherein each strip-shaped optical microstructure MS The strips extend in a direction substantially perpendicular to the first surface S1, and the strip-shaped optical microstructures MS are arranged in a direction substantially parallel to the first surface S1. Wherein, the strip-shaped optical microstructures MS can further disperse the light beam B emitted by the light-emitting unit 120 into the light guide plate 110, thereby enabling The light uniformity of the light guide plate 110 is further improved. In detail, each strip-shaped optical microstructure MS may have a V-shaped strip-shaped microstructure MSV in a cross section perpendicular to the strip-shaped optical microstructure MS. The size of the strip-shaped microstructures MSV shown in FIG. 1B is only used to describe the embodiment, and the invention is not limited thereto. Moreover, in other embodiments, strip optical micro-structures MS (such as cylinders, embossed plaques, or polygonal columns, etc.) having different shapes may also be used, and the present invention is not limited thereto.

Furthermore, the hot spot level and hot spot improvement evaluation values of various light guide types can be referred to Table 2 as follows: The pitch of any two adjacent light emitting units 120 is p, and the shortest distance from the light emitting surface of each light emitting unit 120 to the edge of the effective illumination area is a. Therefore, the a/p ratio can represent the number of light-emitting units 120 required for the same illumination effect of the same size of light guide plate. In other words, the higher the a/p ratio, the more illumination is required under the same illumination effect. Unit 120, and vice versa. As can be seen from Table 2, the hot spot level of the light guide plate 110 having the first chamfered surface SA1 and the second chamfered surface SA2 can be reduced to 67% compared to the light guide plate 110' having no chamfered surface SA. In other words, in the case where the light guide plate 110 has only the chamfered surface SA, the light guide plate 110 can effectively reduce the hot spot phenomenon, and at the same time, the number of the light emitting units 120 used can be saved while still achieving a good illumination effect. If the light guide plate 110 has both the first chamfered surface SA1, the second chamfered surface SA2 and the strip-shaped optical microstructure MS, the hot spot level can be further reduced to 55%. Therefore, the light guide plate 110 can effectively increase the uniformity of light emission and save the use of the light-emitting unit 120 by the first chamfered surface SA1, the second chamfered surface SA2 and the strip-shaped optical microstructure MS, so as to enhance the light-emitting effect and cut costs.

In addition, in this embodiment, the backlight module 100 may further include a plurality of optical microstructures M distributed on at least one of the first surface S1 and the second surface S2. In this embodiment, the optical microstructures M are disposed on the first surface S1 and the second surface S2, for example, but the invention is not limited thereto, and the optical microstructures M may be disposed only on the first surface S1 and the second surface. One of the S2s is exemplified by being disposed on the second surface S2 in this embodiment. In detail, when the light is transmitted by the total reflection in the light guide plate 110, the optical microstructures M on the first surface S1 and the second surface S2 may change the reflection condition so that part of the light is scattered by the first surface. S1 emits light, thereby determining the light distribution of the light guide plate 110. For example, the light guide plate 110 is away from the light emitting unit 120. A plurality of optical microstructures M may be disposed on the second surface S2 of the farther region to increase the luminance, and a smaller number of optical micros may be disposed on the second surface S2 of the region of the light guide plate 110 closer to the light emitting unit 120. Structure M to improve the case where the luminance is too strong. In addition, the strip optical micro-structure MS and the first chamfered surface SA1 or the second chamfered surface SA2, which can increase the uniformity when entering the light, can improve the uniformity of the light incident and the light output of the whole light guide plate 110, thereby improving Light output quality and efficiency of the light guide plate 110. In addition, in the embodiment, the backlight module 100 further includes a reflective unit RF disposed adjacent to the second surface S2, wherein the second surface S2 is located between the first surface S1 and the reflective unit RF. The reflection unit RF can reflect the partial light beam B escaping from the second surface S2 and re-enter the light guide plate 110, thereby further improving the light guiding efficiency of the light guide plate 110 and simultaneously increasing the light emitted by the first surface S1. strength.

In summary, the backlight module of the embodiment of the present invention can uniformly distribute the light concentrated on the light incident surface to a region where the light guide plate is farther from the light incident surface by the light guide plate having the chamfered surface. Wherein, the chamfered surface may be a circular arc surface or may include a plurality of planes that are in contact with each other. Moreover, the uniform light-mixing distance of the light guide plate having the chamfered surface is short, thereby reducing the width of the frame, thereby increasing the visible area of the light guide plate, and also saving the number of light-emitting units while still achieving good light-emitting uniformity and strength. In addition, the light guide plate may further have a strip-shaped optical microstructure on the light incident surface and an optical microstructure at least on the first surface or the second surface to further increase the light uniformity of the light guide plate.

However, the above is only the preferred embodiment of the present invention, and the scope of the present invention cannot be limited thereto, that is, the scope and application of the patent application according to the present invention. The simple equivalent changes and modifications made to the description are still within the scope of the present invention. In addition, any of the objects or advantages or features of the present invention are not required to be achieved by any embodiment or application of the invention. In addition, the abstract sections and headings are only used to assist in the search of patent documents and are not intended to limit the scope of the invention. In addition, the abstract sections and headings are only used to assist in the search of patent documents and are not intended to limit the scope of the invention. In addition, the terms "first", "second" and the like mentioned in the specification or the scope of the claims are only used to name the elements or distinguish different embodiments or ranges, and are not intended to limit the number of elements. Upper or lower limit.

100‧‧‧Backlight module

110‧‧‧Light guide plate

120‧‧‧Lighting unit

B‧‧‧beam

C1, C2‧‧‧ Curvature Center

D‧‧‧Width

H‧‧‧thickness

IL‧‧‧ luminous surface

L‧‧‧ length

M‧‧‧ optical microstructure

MS‧‧‧ strip optical microstructure

R‧‧‧ radius of curvature

RF‧‧‧reflection unit

RP‧‧‧ arc reference surface

RS‧‧‧ reference plane

S1‧‧‧ first surface

S2‧‧‧ second surface

SA1‧‧‧ first chamfered surface

SA2‧‧‧Second chamfered surface

SI‧‧‧Into the glossy surface

S’‧‧‧dotted section

T‧‧‧cut plane

Θ‧‧‧incident angle

Claims (20)

A backlight module includes: a light guide plate comprising: a first surface; a second surface opposite to the first surface; a light incident surface connecting the first surface and the second surface; and a first surface a chamfered surface, the first chamfered surface is connected to the first surface and the light incident surface; and at least one light emitting unit is disposed beside the light incident surface, wherein the light emitting unit has a light emitting surface opposite to the light incident surface, a width D of the light emitting surface in a direction perpendicular to the first surface, the first chamfered surface having a circular arc reference surface, the circular arc reference surface being perpendicular to the first surface and perpendicular to the light incident surface A section cut by a reference plane is a circular arc line having a radius of curvature R, and a length of the first chamfered surface in a direction perpendicular to the incident surface is L, and the light guide plate is The thickness in the direction perpendicular to the first surface is H, and the backlight module satisfies the following formula: The backlight module of claim 1, further comprising a plurality of strip-shaped optical microstructures disposed on the light-incident surface, wherein each of the strip-shaped optical microstructures is substantially perpendicular to the first surface The direction extends and the strip of optical microstructures are aligned along a direction substantially parallel to the first surface. The backlight module of claim 1, wherein the first chamfered surface is a circular arc surface. The backlight module of claim 1, wherein the first chamfered surface comprises a plurality of planes that are bent to meet. The backlight module of claim 4, wherein the planes that are bent to meet each other are inscribed planes of the circular arc reference surface. The backlight module of claim 4, wherein the planes that are bent to meet each other are an circumscribed plane of the circular arc reference surface. The backlight module of claim 1, wherein the light guide plate further comprises a second chamfered surface, the second chamfered surface connecting the second surface and the light incident surface. The backlight module of claim 7, wherein the second chamfered surface has a circular arc reference surface, the circular arc reference surface being a reference perpendicular to the first surface and perpendicular to the light incident surface The section cut by the plane is a circular arc line having a radius of curvature R, and the length of the second chamfered surface in the direction perpendicular to the light incident surface is L, and the light guide plate is perpendicular to The thickness of the first surface is H, and the backlight module satisfies the following formula: The backlight module of claim 1, further comprising a reflective unit disposed adjacent to the second surface, wherein the second surface is located between the first surface and the reflective unit. The backlight module of claim 1, further comprising a reflective unit disposed adjacent to the first surface, wherein the first surface is located on the second surface Between the reflective units. a light guide plate for guiding a light beam emitted by a light source, the light source having a light emitting surface, the light guide plate comprising: a first surface; a second surface opposite to the first surface; and a light incident surface Connecting the first surface and the second surface; at least a first chamfered surface, the first chamfered surface connecting the first surface and the light incident surface; wherein the light emitting surface of the light source is opposite to the light incident surface, and The light emitting surface has a width D in a direction perpendicular to the first surface, and the first chamfered surface has a circular arc reference surface which is perpendicular to the first surface and perpendicular to the light incident surface A section of a reference plane is a circular arc line having a radius of curvature R, and a length of the first chamfered surface in a direction perpendicular to the light incident surface is L, the light guide plate The thickness in the direction perpendicular to the first surface is H, and the light guide plate satisfies the following formula: The light guide plate of claim 11, further comprising a plurality of strip-shaped optical microstructures disposed on the light-incident surface, wherein each of the strip-shaped optical microstructures is substantially perpendicular to the first surface Extending, and the strip of optical microstructures are aligned along a direction substantially parallel to the first surface. The light guide plate of claim 11, wherein the first chamfered surface is a circular arc surface. The light guide plate of claim 11, wherein the first chamfered surface comprises a plurality of planes that are bent to meet. The light guide plate of claim 14, wherein the planes that are bent to meet are inscribed planes of the circular arc reference surface. The light guide plate of claim 14, wherein the planes that are bent to meet each other are an circumscribed plane of the circular arc reference surface. The light guide plate of claim 11, wherein the light guide plate further comprises a second chamfered surface, the second chamfered surface connecting the second surface and the light incident surface. The light guide plate of claim 17, wherein the second chamfered surface has a circular arc reference surface, the circular arc reference surface being perpendicular to the first surface and perpendicular to a reference plane of the light incident surface The cut line is a circular arc line having a radius of curvature R, and the length of the second chamfered surface in a direction perpendicular to the light incident surface is L, the light guide plate is perpendicular to the The thickness in the direction of the first surface is H, and the backlight module satisfies the following formula: The backlight module of claim 11, further comprising a reflective unit disposed adjacent to the second surface, wherein the second surface is located between the first surface and the reflective unit. The backlight module of claim 11, further comprising a reflective unit disposed adjacent to the first surface, wherein the first surface is located between the second surface and the reflective unit.