CN102080789B - Liquid crystal display and backlight module thereof - Google Patents

Abstract

A liquid crystal display and a backlight module thereof are provided, the backlight module comprises a light guide plate and a linear light source. The light guide plate is provided with an ejection light surface and a lateral light incident surface, and the ejection light surface comprises a peripheral area and an effective illumination area. The linear light source includes a circuit board, a plurality of solid state light emitting elements, and a reflector. The solid light-emitting elements are arranged on the circuit board and electrically connected with the circuit board, light beams provided by the solid light-emitting elements enter the light guide plate from the side light incident surface, and the reflector covers part of the peripheral area. In addition, the reflector comprises a plurality of first reflecting parts corresponding to the solid-state light-emitting elements and a plurality of second reflecting parts connected between two adjacent first reflecting parts, each first reflecting part and each second reflecting part extend from the edge of the light-ejecting surface to the direction of the effective illumination area, and the extension length of each first reflecting part is smaller than that of each second reflecting part. The invention can effectively improve the facula generated by the backlight module.

Description

Liquid crystal display and its backlight module

technical field

The present invention relates to a liquid crystal display (liquid crystal display, LCD), and in particular to a backlight module.

Background technique

Liquid crystal displays have become the main focus of display research in recent years because they have advantages that cannot be achieved by displays made of traditional cathode ray tubes (CRTs), such as low-voltage operation, no radiation scattering, light weight, and small size. issues, and is constantly developing towards colorization.

Since the liquid crystal display is a non-self-illuminating display, it needs the backlight module to provide the required light to achieve the display function. In recent years, with the improvement of environmental awareness, the light-emitting elements used in the backlight module have been gradually converted from cold cathode fluorescent lamps (CCFL) to more environmentally friendly light-emitting diode elements. When the light-emitting diode element is applied in the backlight module, taking the side-illuminated backlight module as an example, the light-emitting diode element is usually arranged on a strip-shaped printed circuit board to form a light-emitting diode light bar (LED light bar), and the light-emitting diode The light bar is usually electrically connected to a control circuit board through a flexible printed circuit (FPC).

FIG. 1 is a schematic top view of a light guide plate and LED light bars in a known side-illuminated backlight module. Referring to FIG. 1 , a known side-illuminated backlight module 100 includes a light guide plate 110 and a linear light source 120 . The light guide plate has a top light exit surface 112 and a side light incident surface 114 connected to the top light exit surface 112 , and the top light exit surface 112 includes a peripheral area 112 a connected to the side light incident surface 114 and an effective lighting area 112 b. It can be seen from FIG. 1 that the linear light source 120 is arranged beside the side light incident surface 114, and the linear light source 120 includes a circuit board 122 and a plurality of LED elements 124, and the LED elements 124 are arranged on the circuit board 122 and connected to the circuit board. 122 is electrically connected.

As shown in FIG. 1 , in the linear light source 120 , the pitch between any two adjacent LED elements 124 is P, and the shortest distance from the light emitting surface of each LED element 124 to the edge of the effective lighting area 112 b is A. In order to make the brightness uniform in the effective lighting area 112b, the manufacturer will determine the optimal A/P ratio (A/P ratio) according to the light divergence angle α of the LED element 124. However, at present, liquid crystal displays are gradually developing toward narrow bezel design. To meet the design requirements of narrow bezel, the shortest distance A must be reduced. Alternating light and dark spots (hot spots) will appear in the effective lighting area 112b, and the shadows in FIG. 1 refer to areas with low brightness. This light problem can be solved by reducing the pitch P, but when the pitch P is reduced, the manufacturer must use a larger number of LED elements 124 , resulting in an increase in cost.

Based on the above, how to improve the light spots caused by the low A/P ratio without greatly increasing the production cost is one of the urgent issues to be solved at present.

Contents of the invention

In view of this, the present invention provides a backlight module and a liquid crystal display with the backlight module.

The invention provides a backlight module, which includes a light guide plate and a linear light source. The light guide plate has a top light exit surface and a side light incident surface connected with the top light exit surface, and the top light exit surface includes a peripheral area connected with the side light incident surface and an effective lighting area. The linear light source is arranged beside the side light incident surface, and the linear light source includes a circuit board, a plurality of solid-state light emitting elements and a reflector. The solid-state light-emitting element is arranged on the circuit board and electrically connected with the circuit board. The solid-state light-emitting element is located between the circuit board and the side light-incident surface, and the light beam provided by each solid-state light-emitting element enters the light guide plate from the side light-incidence surface. The reflector covers part of the peripheral area. In addition, the reflector includes a plurality of first reflective portions corresponding to the solid-state light-emitting elements and a plurality of second reflective portions connected between two adjacent first reflective portions, each first reflective portion and each second reflective portion are composed of The edge of the projecting light surface extends toward the direction of the effective lighting area, and the extension length of each first reflection part is smaller than the extension length of each second reflection part.

The present invention further proposes a liquid crystal display, which includes the above-mentioned backlight module and a liquid crystal display panel, wherein the liquid crystal display panel is arranged above the light-emitting surface, the liquid crystal display panel has a display area and a peripheral circuit area, and the display area is located on the leading edge. The light plate is above the effective lighting area, and the peripheral circuit area is located above the peripheral area of the light guide plate.

In an embodiment of the present invention, the aforementioned light guide plate has a scattering surface, the scattering surface is connected to the side light incident surface, and the scattering surface is opposite to the light emitting surface.

In an embodiment of the present invention, the above-mentioned backlight module may further include a bottom reflection sheet, and the bottom reflection sheet is disposed under the scattering surface.

In an embodiment of the present invention, the aforesaid circuit board has a device installation surface, and the solid-state light-emitting device is arranged on the device installation surface, and the device installation surface is substantially perpendicular to the light emitting surface.

In an embodiment of the present invention, the aforesaid circuit board has a device installation surface, and the solid-state light emitting device is arranged on the device installation surface, and the device installation surface is substantially parallel to the lateral light incident surface.

In an embodiment of the present invention, each of the aforementioned solid-state light emitting devices includes a light emitting diode device.

In an embodiment of the present invention, the width of each of the above-mentioned first reflective parts is substantially equal to the width of the solid-state light-emitting element, and the width of each second reflective part is substantially equal to the distance between any two adjacent solid-state light-emitting elements ( spacing).

In an embodiment of the present invention, the aforementioned first reflective portion and the second reflective portion are substantially parallel to the light emitting surface.

In an embodiment of the present invention, the aforementioned reflector may further include an assembly part connected with the linear light source, the assembly part is connected with the first reflection part and the second reflection part, and the assembly part has a plurality of openings, and is solid The light emitting element is embedded in the opening of the assembly part.

In an embodiment of the present invention, the aforementioned assembly part is connected to the circuit board.

In an embodiment of the present invention, the aforementioned reflector may further include an assembly part connected to the linear light source, the assembly part is connected to the first reflection part and the second reflection part, and the assembly part includes a plurality of strip structures, and Each solid-state light-emitting element is respectively located between two adjacent strip structures.

In an embodiment of the present invention, the aforesaid strip structure is connected to a circuit board.

Since the reflector of the present invention has a first reflective portion and a second reflective portion with different extension lengths, the light distribution intensity between any two adjacent solid-state light-emitting elements can be effectively improved through the second reflective portion, so the present invention can effectively Improve the light spots produced by the backlight module.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail with reference to the accompanying drawings.

Description of drawings

FIG. 1 is a schematic top view of a light guide plate and LED light bars in a known side-illuminated backlight module.

FIG. 2 is a schematic diagram of a liquid crystal display according to a first embodiment of the present invention.

Fig. 2' is a schematic diagram of another liquid crystal display according to the first embodiment of the present invention.

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

FIG. 4 is a schematic diagram of a liquid crystal display according to a second embodiment of the present invention.

Fig. 4' is a schematic diagram of another liquid crystal display according to the second embodiment of the present invention.

Wherein, the reference signs are explained as follows:

100: side-lit backlight module

110: light guide plate

112: Top out the glossy surface

112a: Perimeter area

112b: effective lighting area

120: linear light source

122: circuit board

124: LED element

A: shortest distance

P: Interval

α: light divergence angle

200: side-lit backlight module

210: light guide plate

212: Top out the glossy surface

212a: Surrounding area

212b: effective lighting area

214: side light incident surface

216: Scattering surface

220: linear light source

222: circuit board

222a: component setting surface

224: LED element

226, 226’, 226”, 226”’: reflector

226a: first reflection part

226b: second reflection part

226c, 226c': assembly department

226d: opening

300: LCD display panel

310: display area

320: Peripheral line area

LCD, LCD': liquid crystal display

L1, L2: extension length

R: bottom reflector

S: strip structure

Detailed ways

【The first embodiment】

FIG. 2 is a schematic diagram of a liquid crystal display according to the first embodiment of the present invention, and FIG. 3 is a schematic top view of the backlight module according to the first embodiment of the present invention. Referring to FIG. 2 , the liquid crystal display LCD of this embodiment includes a backlight module 200 and a liquid crystal display panel 300 , wherein the liquid crystal display panel 300 is disposed above the backlight module 200 . In this embodiment, the liquid crystal display panel 300 is, for example, a transmissive LCD panel or a transflective LCD panel.

As shown in FIGS. 2 and 3 , the backlight module 200 includes a light guide plate 210 and a linear light source 220 . The light guide plate 210 has a top light exit surface 212 and a side light incident surface 214 connected to the top light exit surface 212, and the top light exit surface 212 includes a peripheral area 212a connected to the side light incident surface 214 and an effective lighting area 212b . The linear light source 220 is disposed beside the side light incident surface 214 , and the linear light source 220 includes a circuit board 222 , a plurality of solid state light emitting elements 224 and a reflector 226 . The solid-state light-emitting elements 224 are arranged on the circuit board 222 and are electrically connected to the circuit board 222. The solid-state light-emitting elements 224 are located between the circuit board 222 and the side light-incident surface 214, and the light beams provided by each solid-state light-emitting element 224 are from the side. The light incident surface 214 enters the light guide plate 210, and the reflector 226 covers part of the peripheral area 212a. In addition, the liquid crystal display panel 300 is located above the light emitting surface 212 of the light guide plate 210. The liquid crystal display panel 300 has a display area 310 and a peripheral circuit area 320, and the display area 310 is located above the effective lighting area 212b of the light guide plate 210. The peripheral circuit The area 320 is located above the peripheral area 212 a of the light guide plate 210 .

As can be seen from FIG. 2 , in addition to the top light exit surface 212 and the side light incident surface 214, the light guide plate 210 also has a scattering surface 216, the scattering surface 216 is connected to the side light incident surface 214, and the scattering surface 216 is connected to the top light exit surface. The faces 212 are opposite. In this embodiment, the scattering surface 216 has, for example, dots with a specific arrangement density, V-shaped grooves (V-shaped grooves) or other optical microstructures (micro-structures), so that the incident light from the side light incident surface 214 to the light guide The light in the light panel 210 is easily scattered, which increases the probability of the light exiting from the light emitting surface 212 . In other embodiments of the present invention, the backlight module 200 may optionally arrange a bottom reflection sheet R under the scattering surface 216, so as to fully reflect part of the light leaving the light guide plate 210 from the scattering surface 216 back into the light guide plate 210, and further The light utilization rate of the backlight module 200 is improved.

The circuit board 222 has an element installation surface 222a, and the solid state light emitting element 224 is disposed on the element installation surface 222a, the element installation surface 222a of the circuit board 222 is substantially perpendicular to the light-emitting surface 212 of the light guide plate 210, and the elements of the circuit board 222 The installation surface 222 a is substantially parallel to the lateral light incident surface 214 of the light guide plate 210 . However, when the angle between the side light incident surface 214 and the light emitting surface 212 is not 90 degrees, the component mounting surface 222a of the circuit board 222 is not necessarily perpendicular to the light emitting surface 212 of the light guide plate 210, and It is not necessary to be parallel to the side light incident surface 214 of the light guide plate 210 . The designer can moderately change the angle between the component disposing surface 222a and the top light exit surface 212 and the side light entrance surface 214 according to the actual requirements of the product. In addition, the circuit board 222 is, for example, an FR-4 printed circuit board, an FR-5 printed circuit board, a metal alloy printed circuit board (MC-PCB), a flexible printed circuit (FPC) and the like.

In this embodiment, the solid state light emitting device 224 is, for example, a light emitting diode device. Taking the light emitting diode element as an example, it can be a surface mount type package or other types of packages. In addition, the LED elements used in this embodiment are top emission LED elements. Of course, other types of LED elements can also be used in other embodiments of the present invention.

Based on the above, the reflector 226 includes a plurality of first reflective portions 226a corresponding to the solid-state light emitting elements 224 and a plurality of second reflective portions 226b connected between two adjacent first reflective portions 226a, each first reflective portion 226a Each second reflective portion 226b extends from the edge of the light emitting surface 212 toward the direction of the effective lighting area 212b, and the extension length L1 of each first reflective portion 226a is shorter than the extension length L2 of each second reflective portion 226b. For example, the width of the first reflective portion 226 a is substantially equal to the width of the solid state light emitting device 224 , and the width of the second reflective portion 226 b is substantially equal to the distance between any two adjacent solid state light emitting devices 224 . Of course, in this embodiment, the widths of the first reflective portion 226a and the second reflective portion 226b can also be moderately changed. For example, we can also make the width of the first reflective portion 226a slightly larger than the width of the solid-state light emitting element 224, and The width of the second reflective portion 226 b is slightly smaller than the distance between any two adjacent solid-state light emitting elements 224 .

Fig. 2' is a schematic diagram of another liquid crystal display according to the first embodiment of the present invention. Please refer to Fig. 2 and Fig. 2', the reflector 226" in Fig. 2' is similar to the reflector 226 in Fig. The edge of the reflector 226" at the bend is straight.

It can be seen clearly from FIG. 2 and FIG. 3 that the plane where the first reflective portion 226 a and the second reflective portion 226 b of the reflector 226 are located is substantially parallel to the plane where the light emitting surface 212 is located. In addition, the first reflective portion 226 a with a shorter length ( L1 ) can be used to shield the solid-state light emitting device 224 to avoid light leakage, and the second reflective portion 226 b with a longer length ( L2 ) can be used to reduce light spots mentioned in the prior art. In detail, compared with the area covered by the first reflective portion 226a of the peripheral region 212a, the area covered by the second reflective portion 226b of the peripheral region 212a is larger, so the second reflective portion 226b can effectively enhance the The distribution of light intensity in corresponding areas between adjacent solid-state light emitting elements 224 can further suppress the occurrence of light spots. When the light spot is suppressed due to the setting of the second reflector 226b, we can further reduce the shortest distance A from the light-emitting surface of each LED element 224 to the edge of the effective illumination area 212b, that is, the light-emitting surface of the LED element 224 to the edge of the effective illumination area 212b. The shortest distance between the edges of the display area 310 can easily meet the design requirement of a narrow frame.

In addition to the first reflection part 226a and the second reflection part 226b, the reflector 226 of this embodiment may further include an assembly part 226c connected with the linear light source 220, the assembly part 226c and the first reflection part 226a and the second reflection part The part 226b is connected, and the assembling part 226c has a plurality of openings 226d, and the solid state light emitting element 224 is embedded in the openings 226d of the assembling part 226c. For example, the aforementioned assembling portion 226c is fixed on the circuit board 222 by glue or other methods.

Based on the above, the reflector 226 of this embodiment is formed, for example, by cutting and bending a piece of plate material. In other words, the materials of the first reflective part 226a, the second reflective part 226b and the assembly part 226c are the same; for example, the reflector The material of 226 can be white reflection or silver reflection material. The shapes of the first reflective portion 226a, the second reflective portion 226b, and the assembly portion 226c can be determined through the aforementioned cutting and bending processes.

【Second Embodiment】

FIG. 4 is a schematic diagram of a liquid crystal display according to a second embodiment of the present invention. Please refer to Fig. 4, the liquid crystal display LCD' of this embodiment is similar to the liquid crystal display LCD of the first embodiment, but the main difference between the two is that: the reflector 226' of this embodiment includes a first reflector 226a, a The second reflection part 226b and an assembly part 226c' connected with the linear light source 220, the assembly part 226c' is connected with the first reflection part 226a and the second reflection part 226b, and the assembly part 226c' includes a plurality of strip structures S, and Each solid state light emitting element 224 is located between two adjacent strip structures S respectively. For example, the aforementioned assembling portion 226c' is fixed on the circuit board 222 by glue or other methods.

Fig. 4' is a schematic diagram of another liquid crystal display according to the second embodiment of the present invention. Please refer to Figure 4 and Figure 4', the reflector 226"' in Figure 4' is similar to the reflector 226' in Figure 4, but the main difference between the two is that the edge of the reflector 226' at the bend is sawtooth shape, and the edge of the reflector 226"' at the bend is straight.

The foregoing embodiments of the present invention adopt a reflector with a first reflective portion and a second reflective portion with different extension lengths, and through the second reflective portion, the intensity of light distribution between any two adjacent solid-state light-emitting elements is effectively improved, so as to Effectively improve the light spots produced by the backlight module.

Although the present invention has been disclosed as above with the embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some modifications and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope defined by the appended claims.

Claims (22)

1. A backlight module, comprising: A light guide plate has a top light exit surface and a side light incident surface connected to the top light exit surface, wherein the top light exit surface includes a peripheral area connected to the side light incident surface and an effective lighting area; A linear light source is arranged beside the side light incident surface, and the linear light source includes: a circuit board; A plurality of solid-state light-emitting elements are arranged on the circuit board and electrically connected to the circuit board. The plurality of solid-state light-emitting elements are located between the circuit board and the side light-incident surface, and each of the solid-state light-emitting elements is The provided light beam enters the light guide plate from the side light incident surface; and A reflector covering part of the peripheral area, the reflector comprising a plurality of first reflectors corresponding to the plurality of solid-state light-emitting elements and a plurality of second reflectors connected between two adjacent first reflectors Each of the first reflectors and each of the second reflectors extend from the edge of the light emitting surface toward the direction of the effective lighting area, and the extension length of each of the first reflectors is shorter than that of each of the second reflectors. extension length of the section; Wherein the light guide plate has a scattering surface, the scattering surface is connected with the side light incident surface, and the scattering surface is opposite to the light emitting surface. 2. The backlight module as claimed in claim 1, further comprising a bottom reflection sheet disposed under the scattering surface. 3. The backlight module as claimed in claim 1, wherein the circuit board has a device setting surface, and the plurality of solid-state light-emitting devices are disposed on the device setting surface, and the component setting surface is substantially perpendicular to the ejected light noodle. 4. The backlight module as claimed in claim 1, wherein the circuit board has a device installation surface, and the plurality of solid-state light emitting devices are disposed on the device installation surface, and the device installation surface is substantially parallel to the lateral direction incident side. 5. The backlight module of claim 1, wherein each of said solid state light emitting elements comprises a light emitting diode element. 6. The backlight module according to claim 1, wherein the width of each of the first reflective parts is substantially equal to the width of the solid-state light-emitting element, and the width of each of the second reflective parts is substantially equal to any two phases. The spacing between adjacent solid state light emitting elements. 7. The backlight module as claimed in claim 1, wherein the plurality of first reflective portions and the plurality of second reflective portions are substantially parallel to the light emitting surface. 8. The backlight module according to claim 1, wherein the reflector further comprises an assembly part connected with the linear light source, the assembly part is connected with the plurality of first reflection parts and the plurality of second reflection parts , and the assembly part has a plurality of openings, and the plurality of solid-state light emitting elements are embedded in the plurality of openings. 9. The backlight module as claimed in claim 8, wherein the assembly part is connected to the circuit board. 10. The backlight module according to claim 1, wherein the reflector further comprises an assembly part connected with the linear light source, the assembly part is connected with the plurality of first reflection parts and the plurality of second reflection parts , and the assembly part includes a plurality of strip structures, and each of the solid-state light-emitting elements is respectively located between two adjacent strip structures. 11. The backlight module as claimed in claim 10, wherein the plurality of strip structures are connected to the circuit board. 12. A liquid crystal display comprising: A backlight module as claimed in claim 1; and A liquid crystal display panel is disposed above the light emitting surface, wherein the liquid crystal display panel has a display area and a peripheral circuit area, the display area is located above the effective lighting area, and the peripheral circuit area is located above the peripheral area. 13. The liquid crystal display as claimed in claim 12, wherein the backlight module further comprises a bottom reflection sheet disposed under the scattering surface. 14. The liquid crystal display as claimed in claim 12, wherein the circuit board has an element placement surface, and the plurality of solid-state light-emitting elements are disposed on the element placement surface, and the element placement surface is substantially perpendicular to the top-emitting light noodle. 15. The liquid crystal display as claimed in claim 12, wherein the circuit board has an element installation surface, and the plurality of solid-state light emitting elements are disposed on the element installation surface, and the element installation surface is substantially parallel to the lateral direction incident side. 16. The liquid crystal display of claim 12, wherein each of said solid state light emitting elements comprises a light emitting diode element. 17. The liquid crystal display as claimed in claim 12, wherein the width of each of the first reflective portions is substantially equal to the width of the solid-state light-emitting element, and the width of each of the second reflective portions is substantially equal to any two phases. The spacing between adjacent solid state light emitting elements. 18. The liquid crystal display as claimed in claim 12, wherein the plurality of first reflective portions and the plurality of second reflective portions are substantially parallel to the light emitting surface. 19. The liquid crystal display as claimed in claim 12, wherein the reflector further comprises an assembly part connected with the linear light source, the assembly part is connected with the plurality of first reflection parts and the plurality of second reflection parts , and the assembly part has a plurality of openings, and the plurality of solid-state light emitting elements are embedded in the plurality of openings. 20. The liquid crystal display as claimed in claim 19, wherein the assembly part is connected to the circuit board. 21. The liquid crystal display as claimed in claim 12, wherein the reflector further comprises an assembly part connected with the linear light source, the assembly part is connected with the plurality of first reflection parts and the plurality of second reflection parts , and the assembly part includes a plurality of strip structures, and each of the solid-state light-emitting elements is respectively located between two adjacent strip structures. 22. The liquid crystal display as claimed in claim 21, wherein the plurality of strip structures are connected to the circuit board.

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