CN101608759B - Backlight module - Google Patents

Abstract

The invention discloses a backlight module, comprising a light guide board and a plurality of light emitting elements. The light guide board comprises a light-in surface and a light-out surface, wherein the light-out surface is provided with a visible region. The light emitting elements are arranged on the light-in surface of the light guide board, wherein each light emitting element comprises a light emitting surface and an optical axis vertical to the light emitting surface. The optical axes are approximately crossed at a central point of the visible region.

Description

Backlight module

technical field

The invention relates to a backlight module, and in particular to a backlight module capable of improving overall brightness.

Background technique

Generally speaking, a liquid crystal display device usually includes a liquid crystal display panel and a backlight module, wherein the backlight module is mainly used to provide a surface light source required by the liquid crystal display panel when displaying.

FIG. 1 is a schematic top view of a known backlight module. For convenience of illustration, FIG. 1 only shows the relative positions of the light emitting diodes in the backlight module and the light guide plate, and does not show the optical films located above and below the light guide plate. Please refer to FIG. 1 , the backlight module 100 includes a plurality of LEDs 110 and a light guide plate 120 . The light guide plate 120 has long sides and short sides, and the light emitting diodes 110 are usually arranged on the long side or the short side of the light guide plate 120 as the light source of the backlight module 100, wherein FIG. 1 shows that the light emitting diodes 110 are arranged on the light guide plate 120 The short side, in other words, the short side is a light incident surface 122 of the light guide plate 120 .

Each LED 110 has a light emitting surface 112 and an optical axis 114 perpendicular to the light emitting surface 112 . In detail, the arrangement of the light emitting diodes 110 arranged on the short side of the light guide plate 120 is generally arranged in parallel to straight lines, that is, the optical axes 112 of each light emitting diode 110 are parallel to each other, as shown in FIG. 1 .

Since the light-emitting angle of the light-emitting diodes 110 is usually about 110 degrees, and the arrangement of the light-emitting diodes 110 on the short side of the light guide plate 120 is shown in FIG. The light path is relatively low, and the light path incident on the light guide plate 120 will easily scatter out of the light guide plate 120 as it approaches the edge of the light guide plate 120 , thereby reducing the light utilization efficiency of the light emitting diodes 110 . In this way, the overall brightness of the backlight module 100 will not be easily improved.

Contents of the invention

In view of this, the present invention provides a backlight module, which can concentrate the light incident on the light guide plate, increase the refraction times of the light in the light guide plate, and have better overall brightness.

The invention provides a backlight module, which includes a light guide plate and a plurality of light emitting elements. The light guide plate has a light incident surface and a light exit surface, wherein the light exit surface has a visible area. The light emitting elements are arranged on the light incident surface of the light guide plate, wherein each light emitting element has a light emitting surface and an optical axis perpendicular to the light emitting surface. These optical axes intersect approximately at the center point of the viewing zone.

In an embodiment of the present invention, an odd number of light emitting elements is arranged on the light incident surface of the light guide plate.

In an embodiment of the invention, the viewable area has a width X in the horizontal direction and a length Y in the vertical direction. There is an angle θ _m between the optical axis of each light-emitting element and the vertical direction of the visible area:

${\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; tan</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; |</span><span\; class="notranslate">\; (</span>\frac{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; x</span>}}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; Y</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; |</span>$

Wherein, 2n+1 light emitting elements are arranged on the light incident surface of the light guide plate, and n≠0, m is a positive integer of 0˜n, and −1<σ<1.

In an embodiment of the invention, the viewable area has a width X in the horizontal direction and a length Y in the vertical direction. The visible area has a centerline in the vertical direction, and a distance _dm between each light-emitting element and the centerline along the horizontal direction is:

${\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; |</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; a</span>}}{\mathrm{<span\; class="notranslate">\; Y</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; )</span>\frac{\mathrm{<span\; class="notranslate">\; x</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; |</span>$

Wherein, 2n+1 light-emitting elements are arranged on the light incident surface of the light guide plate, n≠0, m is a positive integer from 0 to n, a is the distance from the light incident surface of the light guide plate to the edge of the visible area, and - 0.5<σ<0.5.

In an embodiment of the present invention, an even number of light emitting elements is arranged on the light incident surface of the light guide plate.

In an embodiment of the present invention, the visible area has a width X in the horizontal direction and a length Y in the vertical direction, and there is an angle θ _m between the optical axis of each light emitting element and the vertical direction of the visible area for:

${\mathrm{\&theta;}}_m={\mathrm{the\; tan}}^{-1}\left|\left(\frac{((2m-1)+\mathrm{\&sigma;})x}{2n}\right)\right|,$ And θ _m ≠0

Wherein, 2n light emitting elements are arranged on the light incident surface of the light guide plate, and n≠0, m is a positive integer of 1˜n, and −0.5<σ<0.5.

In an embodiment of the invention, the viewable area has a width X in the horizontal direction and a length Y in the vertical direction. The visible area has a centerline in the vertical direction, and a distance _dm between each light-emitting element and the centerline along the horizontal direction is:

$d_m=\left|(1+\frac{2a}{Y})((2m-1)+\mathrm{\&sigma;})\frac{x}{4\mathrm{no}}\right|,$ and d _m ≠0

Wherein, 2n light-emitting elements are arranged on the light incident surface of the light guide plate, n≠0, m is a positive integer from 1 to n, a is the distance from the light incident surface of the light guide plate to the edge of the visible area, and -1< σ<1.

In an embodiment of the present invention, the light incident surface of the light guide plate has a plurality of grooves, and a light emitting element is placed in each groove.

In an embodiment of the present invention, the visible area has a centerline in the vertical direction, and the grooves each have an inclination angle, and the inclination angles of the grooves are smaller as they are closer to the centerline of the light guide plate.

In an embodiment of the invention, the backlight module further includes an optical film set and a reflection sheet. The optical film group is arranged above the light emitting surface of the light guide plate. The reflection sheet is arranged on the surface of the light guide plate facing the side facing the light exit surface.

Based on the above, the backlight module of this embodiment adopts the above formula by making the optical axis of each light-emitting element intersect at the center point of the visible area, and matching the number of light-emitting elements (such as an odd number or an even number) to make the light-emitting elements It is arranged on the light-incident surface, so that the overall brightness of the light-emitting surface of the light guide plate can be improved, so that the backlight module can provide a backlight with better brightness.

In order to make the above-mentioned purposes, features, and advantages of the present invention more obvious and easy to understand, the accompanying drawings are described in detail as follows:

Description of drawings

FIG. 1 is a schematic top view of a known backlight module;

2A is a schematic top view of a backlight module according to an embodiment of the present invention;

Fig. 2B is a cross-sectional view of the backlight module shown along line AA' of Fig. 2A;

FIG. 3 is a schematic top view of a backlight module according to another embodiment of the present invention.

Among them, reference signs

100, 200, 300: backlight module 110: light emitting diode

120, 210: Light guide plate 122, 212: Light incident surface

112, 222: Light emitting surface 114, 224: Optical axis

214: Light-emitting surface 214a: Visual area

216: groove 220: light emitting element

230: Optical diaphragm group 240: Reflector

C1: Center point P1: Horizontal direction

P2: Vertical direction L1: Centerline

X: Width Y: Length

d _m : distance θ _m : angle

Detailed ways

FIG. 2A is a schematic top view of a backlight module according to an embodiment of the present invention, and FIG. 2B is a cross-sectional view of the backlight module along line AA' of FIG. 2A . For the convenience of illustration, FIG. 2A only shows the relative positions of the light-emitting elements of the backlight module and the light guide plate, and does not show the films positioned above and below the light guide plate. Please refer to FIG. 2A and FIG. 2B at the same time. The backlight module 200 of this embodiment includes a light guide plate 210 and a plurality of light emitting elements 220 . The light guide plate 210 has a light incident surface 212 and a light exit surface 214, wherein the light exit surface 214 has a visible area 214a. The light-emitting elements 220 are disposed on the light-incident surface 212 of the light guide plate 210, wherein each light-emitting element 220 has a light-emitting surface 222 and an optical axis 224 perpendicular to the light-emitting surface 222, and these optical axes 224 roughly intersect in the visible direction. The center point C1 of the area 214a.

In this embodiment, the light from the light-emitting element 220 is adapted to enter the light guide plate 210 from the light-incident surface 212 , refract therein multiple times, and then exit the light-emitting surface 214 . In addition, the light-emitting element 220 is, for example, a light-emitting diode, wherein the type of the light-emitting diode can be side-emitting or top-emitting, depending on the user's design and requirements. In addition, the multiple rays of light emitted by the light-emitting element 220 are generally perpendicular to the light-emitting surface 222 of the light-emitting element 220 , and the center of the light-emitting surface 222 is the position with the strongest light intensity, which is often called the optical axis. Therefore, the optical axis 224 of this embodiment can be defined as the central position of the light emitting surface 222 .

In this embodiment, an odd number of light emitting elements 220 are disposed on the light incident surface 212 of the light guide plate 210 , as shown in FIG. 2A . In detail, 2n+1 light emitting elements 220 are disposed on the light incident surface 212 of the light guide plate 210 , and n is an integer greater than zero. In addition, the viewable area 214a has a width X in the horizontal direction P1 and a length Y in the vertical direction P2. In this embodiment, there is an included angle θ _m between the optical axis 224 of each light emitting element 220 and the vertical direction P2 of the visible area 214a, wherein the included angle θ _m is defined as:

${\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; tan</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; |</span><span\; class="notranslate">\; (</span>\frac{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; x</span>}}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; Y</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; |</span><span\; class="notranslate">\; ,</span>$

m is an integer of 0 to n, and -1<σ<1. In addition, it should be noted that θ ₀ represents the angle between the optical axis of the light-emitting element 220 located in the middle of the plurality of light-emitting elements 220 and the vertical direction P2 of the visible area 214 a.

In addition, the visible area 214a has a centerline L1 in the vertical direction P2, and there is a distance _dm between each light emitting element 220 and the centerline L1 along the horizontal direction P1, where _dm is defined as:

${\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; |</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; a</span>}}{\mathrm{<span\; class="notranslate">\; Y</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; )</span>\frac{\mathrm{<span\; class="notranslate">\; x</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; |</span>$

m is a positive integer from 0 to n, -0.5<σ<0.5, and a is defined as the distance from the light incident surface 212 of the light guide plate 210 to the edge of the visible area 214a, where the light incident surface 212 refers to the parallel visible The plane of the edge of region 214a.

Based on the above structure, if the width X is smaller than the length Y, it means that the light-emitting element 220 is incident on the short side of the light guide plate 210, and because the light-emitting element 220 is arranged on the light incident surface 212 of the light guide plate 210 using the above-mentioned conditions, so, The number of refractions of the light provided by the light emitting element 220 in the light guide plate 210 can be increased. In this embodiment, when the width X is smaller than the length Y, the arrangement of the light-emitting element 220 can increase the number of refractions of the light incident inside the light guide plate 210, and compared with the arrangement of the known technology, it can at least Can be raised to 8.1%.

In addition, if the width X is greater than the length Y, it means that the light-emitting element 220 is incident on the long side of the light guide plate 210. The refraction times of the light incident inside the light guide plate 210 can be increased to at least 50.9% compared with the arrangement using the known technology.

In other words, no matter whether the light provided by the light-emitting elements 220 is incident from the long side or the short side of the light guide plate 210, as long as the optical axis 224 of each light-emitting element 220 roughly intersects at the center point C1 of the visible area 214a, and each light-emitting element When the 220 can be installed on the light incident surface 212 of the light guide plate 210 under the above conditions, the number of refractions of light inside the light guide plate 210 can be increased, thereby increasing the overall brightness of the light exit surface 214 . In addition, the installation concept that the optical axes 222 of each light-emitting element 220 roughly intersect each other in the present invention can also effectively improve the problem of bright and dark bands around the visible area 214a of the light guide plate 210, reduce the difference between bright and dark bands and improve the uniformity of light sex.

In this embodiment, the light incident surface 212 of the light guide plate 210 has a plurality of grooves 216 , and a light emitting element 220 is disposed in each groove 216 , as shown in FIG. 2A . Wherein, the grooves 216 respectively have an inclination angle (not shown), and the inclination angles of the grooves 216 are smaller as they are closer to the central line L1 of the light guide plate 210 . The magnitude of the inclination angle may be substantially the same as the above-mentioned included angle θ _m . The groove 216 can be used as an assembly positioning structure for the light emitting element 220 .

In addition, the backlight module 200 further includes an optical film set 230 and a reflective sheet 240 , as shown in FIG. 2B . In this embodiment, the optical film set 230 is disposed above the light emitting surface 214 of the light guide plate 210 , and the reflective sheet 240 is disposed on the surface of the light guide plate 210 opposite to the light emitting surface 214 . The optical film set 230 can be at least one of a diffusion film, a brightness enhancement film, a uniform film and a composite optical film. In addition, the light guide plate 210 of this embodiment is described by taking a wedge-shaped light guide plate as an example, but the present invention is not limited to this kind of light guide plate.

FIG. 3 is a schematic top view of a backlight module according to another embodiment of the present invention. Similarly, for the convenience of illustration, FIG. 3 only shows the relative positions of the light-emitting elements of the backlight module and the light guide plate, and does not show the films positioned above and below the light guide plate. Please refer to FIG. 2A and FIG. 3 at the same time. The backlight module 300 of this embodiment is similar to the backlight module 200, but the difference between the two is that the arrangement of the light emitting elements 210 of the backlight module 300 is slightly different from that of the backlight module 200. The details are as follows.

In the backlight module 300 , an even number of light emitting elements 220 are disposed on the light incident surface 212 of the light guide plate 210 , as shown in FIG. 3 . In detail, 2n light emitting elements 220 are disposed on the light incident surface 212 of the light guide plate 210 , and n is a positive integer greater than zero. In addition, the viewable area 214a has a width X in the horizontal direction P1 and a length Y in the vertical direction P2. In this embodiment, there is an included angle θ _m between the optical axis 224 of each light emitting element 220 and the vertical direction P2 of the visible area 214a, wherein the included angle θ _m in this embodiment is defined as:

${\mathrm{\&theta;}}_m={\mathrm{the\; tan}}^{-1}\left|\left(\frac{((2m-1)+\mathrm{\&sigma;})x}{2n}\right)\right|,$ And θ _m ≠0

m is a positive integer of 1 to n, and -0.5<σ<0.5.

Similarly, the visible area 214a has a centerline L1 in the vertical direction P2, and there is a distance _dm between each light emitting element 220 and the centerline L1 along the horizontal direction P1, wherein _dm in this embodiment is defined as :

$d_m=\left|(1+\frac{2a}{Y})((2m-1)+\mathrm{\&sigma;})\frac{x}{4\mathrm{no}}\right|,$ and d _m ≠0

And m is a positive integer from 1 to n, a is the distance from the incident surface 212 of the light guide plate 210 to the edge of the visible area 214a, where the incident surface 212 refers to a plane parallel to the edge of the visible area 214a, and- 1<σ<1.

From the above, it can be seen that since the number of light emitting elements 220 of the backlight module 300 is an even number, the conditions for disposing the light emitting elements 220 on the light incident surface 212 also change accordingly, such as parameters such as angle θ _m and distance d _m . Moreover, although the included angle θ _m and the distance d _m will be adjusted according to the number of light-emitting elements 220, however, the same as the above-mentioned backlight module 200, the optical axis 224 of each light-emitting element 220 also roughly intersects in the visible area The center point C1 of 214a is shown in FIG. 3 .

In other words, the backlight module 300 of this embodiment is different from the backlight module 200 only in the number of light-emitting elements 220, wherein the parameter conditions (such as the included angle θ _m , distance d _m ) of the light-emitting elements 220 disposed on the light incident surface 212 will vary with the The number of light-emitting elements 220 is slightly adjusted by using an odd number or an even number. Therefore, the backlight module 300 of this embodiment also has the advantages mentioned in the backlight module 200 , which will not be repeated here.

To sum up, the backlight module of the present invention has at least the following advantages. Firstly, the optical axis of each light-emitting element will roughly intersect at the center point of the visible area. In this way, the light provided by the light-emitting element will be more concentrated in the visible area, thereby improving the overall brightness of the light-emitting surface, and located at The light provided by the light emitting elements at the edge of the light guide plate is also less likely to scatter out of the light guide plate. In addition, for different numbers of light-emitting elements (such as odd or even numbers), the parameter conditions (such as angle θ _m , distance d _m ) of light-emitting elements disposed on the light-incident surface can also be adjusted accordingly, so as to improve the incident light on the light guide plate. The refraction times of the light inside can further improve the overall brightness of the backlight module. In addition, it can improve the phenomenon of bright and dark bands caused by uneven distribution of light sources in the visual area.

Certainly, the present invention also can have other multiple embodiments, without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding Changes and deformations should belong to the scope of protection of the appended claims of the present invention.

Claims (5)

1. A backlight module, characterized in that, comprising: A light guide plate, which has a light incident surface and a light exit surface, wherein the light exit surface has a visible area; and A plurality of light-emitting elements are arranged on the light-incident surface of the light guide plate, wherein each light-emitting element has a light-emitting surface and an optical axis perpendicular to the light-emitting surface, and the optical axis roughly intersects the visible the center point of the area; An odd number of light emitting elements are arranged on the light incident surface of the light guide plate; The visible area has a width X in the horizontal direction and a length Y in the vertical direction, and an included angle θ _m between the optical axis of each light-emitting element and the vertical direction of the visible area is: ${\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; tan</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; |</span><span\; class="notranslate">\; (</span>\frac{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; x</span>}}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; Y</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; |</span>$ Wherein, 2n+1 light emitting elements are arranged on the light incident surface of the light guide plate, and n≠0, m is an integer of 0˜n, and −1<σ<1. 2. The backlight module according to claim 1, wherein the visible area has a width X in the horizontal direction and a length Y in the vertical direction, the visible area has a centerline in the vertical direction, and There is a distance d _m between each light-emitting element and the center line along the horizontal direction: ${\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; |</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; a</span>}}{\mathrm{<span\; class="notranslate">\; Y</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; )</span>\frac{\mathrm{<span\; class="notranslate">\; x</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; |</span>$ Wherein, the light incident surface of the light guide plate is provided with 2n+1 light-emitting elements, n≠0, m is an integer from 0 to n, and a is the distance between the light incident surface of the light guide plate and the edge of the visible area. distance, and -0.5<σ<0.5. 3 . The backlight module according to claim 1 , wherein the light incident surface of the light guide plate has a plurality of grooves, and a light-emitting element is disposed in each groove. 4 . 4. The backlight module according to claim 3, wherein the visible area has a centerline in the vertical direction, and the grooves respectively have an inclination angle, and the closer to the centerline of the light guide plate The inclination angle of the groove is smaller. 5. The backlight module according to claim 1, further comprising: an optical film group, arranged above the light-emitting surface of the light guide plate; and A reflective sheet is arranged on the surface of the light guide plate facing the side facing the light emitting surface.

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