TW200420972A - Back light module and liquid crystal display - Google Patents

Abstract

A back light module comprised a light guide plate, a side light source and a bottom light source is provided. The side light source is disposed on a side of the light guide plate. The bottom light source is disposed on the bottom of the light guide plate. The lights provided by the side light source and the bottom light source could output from the top of the light guide plate. The lights can enhance the brightness of the back light module. In addition, a liquid crystal display comprised a transmissive or transflective liquid crystal panel and the back light module mentioned above is provided.

Description

200420972 V. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to a backlight module (Back Light M odu 1 e) and a liquid crystal display (Liquid Crysta 1 D isp 1 ay, LCD ), And in particular to a backlight module and a liquid crystal display capable of providing a surface light source with high brightness. [Previous Technology] In response to the rapid progress of the multimedia society, most of them benefit from the leaps and bounds of semiconductor components or human-machine display devices. As far as displays are concerned, cathode ray tubes (CRT) have been dominating the display market in recent years due to their excellent display quality and economy. However, for the environment where individuals operate most terminals / display devices on the table, or from the perspective of environmental protection, if the trend of energy saving is predicted, there are still many problems in cathode ray tubes due to space utilization and energy consumption. Demands for light, thin, short, small, and low power consumption cannot effectively provide a solution. Therefore, liquid crystal displays with superior characteristics such as high picture quality, increased space utilization efficiency, low power consumption, and no radiation have gradually become the mainstream of the market. FIG. 1 is a schematic diagram of a conventional liquid crystal display. Please refer to FIG. 1. The liquid crystal display 100 is mainly composed of a liquid crystal panel 110 and a backlight module 120. Among them, the backlight module 120 is disposed at the back of the liquid crystal panel 110, and this back is relative to the user, and the backlight module 120 is composed of a light guide plate 1 2 2. One side light source 1 2 4. A reflecting cover 1 2 6 and a frame 128 (franie). The light guide plate 1 2 2 is, for example, a wedge-shaped light guide plate. The light guide plate 1 2 2 has a top surface 130, a bottom surface 132, and a side surface 134. Among them, the top of the light guide plate 122

103331 wf.pt d Page 5 200420972 V. Description of the invention (2) The surface 1 3 0 is designed as a light emitting surface, the bottom surface of the light guide plate 1 2 2 is designed as a scattering surface, and the side of the light guide plate 1 2 2 The 1 3 4 series is designed as a light incident surface. The side light source 1 2 4 is, for example, a cold cathode lamp (C ο 1 d C ath 〇de Fluorescence Lamp, CCFL), i is located beside the J-plane 1 3 4 of the light guide plate 122, and the side light source 1 The light provided by 24 can be incident on the light guide plate 122 through the side surface 1 3 4 and transmitted and emitted to the top surface 1 30 after being scattered and reflected by the bottom surface 132. From the above, it can be seen that the light emitted from the top surface 130 is a type of surface light source. The reflection cover 1 2 6 is arranged beside the side 1 3 4 of the light guide plate 1 2 2 and covers the side light source 1 2 4. The light provided by the side light source 1 2 4 is concentrated toward the light guide plate through the reflection of the reflection cover 1 2 6. The side of 1 2 2 is illuminated in the direction of 1 3 4. In addition, the frame Φ 1 2 8 is used to carry the above-mentioned light guide plate 1 2 2, the side light source 1 2 4 and the reflection cover 1 2 6 so that the light guide plate 1 2 2, the side light source 1 2 4 and the reflection cover 1 2 6 can Integration. As mentioned above, since the liquid crystal molecules do not emit light by themselves, it is necessary to provide the surface light source required for the LCD panel 110 by the backlight module 120, so that the LCD panel 110 can achieve the display effect and obtain sufficient Brightness and contrast. Since the current LCD display has moved from XGA to a higher resolution, under the limitation of high resolution, because the transmittance of the LCD panel cannot be further improved, it is bound to effectively increase the brightness of the light to meet the high brightness of the LCD display. demand. The most common method to increase the light intensity of liquid crystal displays is to increase the brightness of the side light source. Since most of the side light sources are mainly cold cathode fluorescent lamps (CCFL), only by increasing the tube current, To increase the brightness of the surface of the lamp, but the range of brightness improvement is still very limited.

10333twf.ptd Page 6 200420972 V. Description of the invention (3) The increase of the tube current will greatly increase the power consumed by the backlight module, and the service life of the lamp tube in the module will be greatly shortened. In addition, the conventional method for increasing the light intensity of liquid crystal displays includes increasing the number of lamps, but at the same time increasing the number of lamps, not only the overall power consumption is greatly increased, but also the thickness of the backlight module and The weight is also bound to increase. Such a design does not meet the development trend of light, thin, short, and small liquid crystal displays. In addition, after increasing the number of lamps, an inverter that drives multiple lamps must be designed separately, and the electromagnetic interference (E M I) generated by multiple lamps is also difficult to protect. [Summary of the Invention] Therefore, the object of the present invention is to provide a backlight module, which can increase the overall brightness of the backlight module and the adjustable range of the brightness by adding a bottom light source and a side light source of the original design. Another object of the present invention is to provide a backlight module, which can increase its service life by adding a bottom light source with a side light source of the original design. Yet another object of the present invention is to provide a liquid crystal display, which not only has a high-brightness and high-resolution display capability, but can still meet the demand for miniaturization. Based on the above objective, the present invention provides a backlight module, which is suitable for providing a side light source. The backlight module is composed of a light guide plate, a side light source and a bottom light source. The light guide plate has a top surface, a bottom surface, and at least one side surface. The side light source is arranged beside the side of the light guide plate, and the light provided by the side light source can enter the light guide plate from the side of the light guide plate and pass through the light guide plate.

10333twf.ptd Page 7 200420972 V. Description of the invention (4) The bottom surface is transmitted to the top surface of the light guide plate for emission. The bottom light source is arranged on the bottom surface of the light guide plate, and the light provided by the bottom light source can enter the light guide plate from the bottom surface of the light guide plate and exit from the top surface of the light guide plate. Based on the above objectives, the present invention also provides a liquid crystal display. The liquid crystal display is composed of a liquid crystal panel and a backlight module. The backlight module is composed of a light guide plate, a side light source and a bottom light source. The light guide plate has a top surface, a bottom surface, and at least one side surface. The side light source is arranged beside the side of the light guide plate, and the light provided by the side light source can enter the light guide plate from the side of the light guide plate, pass through the bottom surface of the light guide plate, and then be transmitted to the top surface of the light guide plate for emission. The bottom light source is arranged on the bottom surface of the light guide plate, and the light provided by the bottom light source can enter the light guide plate from the bottom surface of the light guide plate and exit from the top surface of the light guide plate. According to a preferred embodiment of the present invention, the shape of the light guide plate may be wedge-shaped, and the bottom surface of the light guide plate may be made into a stepped surface, or the bottom surface may be designed to have a plurality of recesses, so as to provide the light provided by the side light source. Scattering, and this side light source can be a cold cathode lamp. According to a preferred embodiment of the present invention, the bottom light source may be an organic electroluminescent device, and the organic electroluminescent device is composed of a transparent substrate, an anode, an organic functional layer, and a cathode. The anode is formed on the transparent substrate, the organic functional layer is formed on the anode, and the cathode is formed on the organic functional layer. The organic functional layer is composed of a hole injection layer, a hole conduction layer, an organic light emitting layer, and an electron conduction layer in this order. The hole injection layer is formed on the anode, and the hole conduction layer is formed on the hole.

10333twf.ptd Page 8 200420972 V. Description of the invention (5) The organic light emitting layer is formed on the hole conductive layer and the electron conductive layer is formed between the organic light emitting layer and the cathode. In addition, the above-mentioned organic electroluminescent device is directly formed on a transparent substrate. However, the organic electroluminescent device of the present invention can also be formed directly on the bottom surface of the light guide plate. In this embodiment, when an organic electroluminescent device is fabricated on the bottom surface of the light guide plate, only a flat layer needs to be formed on the bottom surface of the light guide plate to provide a flat surface. Each film layer is sufficient. According to a preferred embodiment of the present invention, in order to improve the brightness presentation of the backlight module and the display capability of the liquid crystal display, a diffuser and a light-enhancing sheet may be arranged on the light-emitting surface of the light guide plate, or beside a side light source. A reflector is configured to cover the side light source. According to a preferred embodiment of the present invention, in order to integrate the light guide plate, the side light source, the bottom light source, and the reflection cover in the backlight module, for example, a frame may be used to carry the main light plate, the side light source, the bottom light source, and the reflection. cover. According to a preferred embodiment of the present invention, the liquid crystal display is, for example, a transmissive panel or a transflective transflective liquid crystal panel. As mentioned above, the present invention additionally arranges a bottom light source on the bottom surface of the light guide plate, and can be used with the original side light source. The addition of the side light source and the bottom light source of the backlight module can provide a high brightness Surface light source, and can further extend the life of the backlight module. In this way, the liquid crystal display can not only meet the needs of high brightness and high resolution, but still maintain the characteristics of lightness, thinness, shortness and smallness.

10333twf.ptd Page 9 200420972 V. Description of the invention (6) In order to make the above and other objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is given below, in conjunction with the accompanying drawings, The detailed description is as follows: [Embodiment Mode] FIG. 2 shows a schematic diagram of a liquid crystal display according to a preferred embodiment of the present invention. Please refer to FIG. 2, the liquid crystal display 2000 is mainly composed of a liquid crystal panel 210 and a backlight module 220. Wherein, the liquid crystal panel 2 10 may be a transmissive or transflective liquid crystal panel, and the backlight module 2 2 0 S has been placed on the back of the liquid crystal panel 2 10, and the back is relative to the user. In other words, the backlight module 2 2 0 is composed of a light guide plate 2 2 2, a side light source 2 2 4, a reflection cover 2 2 6, a frame 2 2 8, a diffusion sheet 2 3 0, a light enhancement sheet 2 3 2 and a bottom light source 2 3 4 · Composition. The light guide plate 2 2 2 can be made into a wedge shape. The light guide plate 222 has a top surface 236, a bottom surface 238, and a side surface 240. The top surface 2 3 6 is designed as a light emitting surface, and the bottom surface 2 3 8 is Designed as a scattering surface, and the side 240 is designed as a light incident surface. In addition, the bottom surface 2 3 8 can be designed as a stepped surface (as shown in Fig. 3) or has a plurality of pits (not shown) to scatter the light provided by the side light sources 2 2 4. The side light source 2 2 4 may be a cold cathode tube (CCFL), which is arranged beside the side 2 2 0 of the light guide plate 2 2 2, and the light provided by the side light source 2 2 4 can be incident on the light guide plate 222 from the side 240. After being scattered by the bottom surface 238, it is transmitted to the top surface 2 3 6 and emitted. From the above, it can be seen that the light emitted from the top surface 2 3 6 is a type of surface light source. The reflection cover 2 2 6 is arranged beside the side 2 2 0 of the light guide plate 2 2 2 and covers

10333twf. Ptd Page 10 200420972 V. Description of the invention (7) The side light source 2 2 4 is provided. The light provided by the side light source 2 2 4 is reflected by the reflection cover 2 2 6 and can be focused toward the light guide plate 2 2 2 The side is illuminated in the direction of 2 4 0. The diffusion sheet 230 is disposed on the top surface 236 of the light guide plate 222, and the light-increasing sheet 232 is disposed on the diffusion sheet 2 3 0. With the above-mentioned reflection cover 2 2 6, the diffusion sheet 2 3 0 and the light-increasing sheet 2 3 2, Improve the brightness display of the backlight module 2000 and the display capability of the liquid crystal display. In addition, the frame 2 2 8 series can carry the light guide plate 2 2 2, the side light source 2 2 4, the bottom light source 2 3 4 and the reflection cover 2 2 6 so that the light guide plate 2 2 2, the tritium light source 2 2 4, and the bottom light source. 2 3 4 and the reflection cover 2 2 6 can be integrated. Fig. 3 is a schematic enlarged sectional view at a range A in Fig. 2, which particularly shows the structure of the bottom light source. Please refer to FIG. 3. In this embodiment, the bottom light source 2 3 4 is an organic electroluminescent element, and the organic electroluminescent element is composed of a transparent substrate 2 4 2, an anode 2 4 4, and an organic functional layer. It is composed of 2 4 6 and cathode 2 4 8. The transparent substrate 24 2 is formed on the bottom surface 2 3 8 of the light guide plate 2 2 2, the anode 2 44 is formed on the transparent substrate 2 42, the organic functional layer 2 4 6 is formed on the anode 244, and the cathode 2 48 It is formed on the organic functional layer 2 4 6 °. In addition, the organic functional layer is composed of a hole injection layer 2 4 6 a, a hole conductive layer 246 b, an organic light emitting layer 246 c, and an electron conductive layer 246 d. The hole injection layer 2 4 6 a is formed on the anode 2 4 4, the hole conduction layer 246 b is formed on the hole injection layer 246 a, and the organic light emitting layer 246 c is formed on the hole conduction layer 2 4 6 d. An electron conducting layer 2 4 6 d is formed between the organic light emitting layer 246 c and the cathode 248. However, in another embodiment, the organic electro-optic light emitting element may be directly formed on the bottom surface 238 of the light guide plate 222. The method is in the light guide plate 222

10333twf. Ptd Page 11 200420972 V. Description of the invention (8) Bottom surface 2 3 8 When fabricating organic electro-excitation light elements, it is only necessary to form a flat layer (not shown in Figure C) on the bottom surface 238 of the light guide plate 222 to provide a flat surface. After that, all the film layers required for fabricating the organic electro-excitation light-emitting element can be formed on the flat layer. Please refer to FIG. 2 and FIG. 3 together. By providing a current to drive the bottom light source 2 3 4 to emit light, the light provided by the bottom light source 2 3 4 can be incident into the light guide plate 222 from the bottom surface 238 of the light guide plate 222. And emitted from the top surface 2 3 6 of the light guide plate 222. At this time, the light emitted from the top surface 2 3 6 is also a type of surface light source. When the LCD display 2 0 is used, the side light source 2 2 4 and the bottom light source 2 3 4 can be driven at the same time. By combining the two light sources, a high-brightness surface light source is provided, so that the liquid crystal panel 2 1 0 has sufficient Brightness, and achieve the best display effect. Of course, when the brightness requirement is not high, the side light source 2 2 4 and the bottom light source 2 3 4 can also be selected and used individually, so as to extend the service life of the backlight module 2000. To sum up, the backlight module and the liquid crystal display of the present invention have at least the following advantages: 1. The backlight module of the present invention can provide a high-brightness surface light source through the addition of the side light source and the bottom light source to improve The overall brightness of the backlight module and the adjustable range of the brightness make the liquid crystal display to meet the requirements of high brightness and high resolution. 2. In the backlight module of the present invention, the side light source and the bottom light source are optional, and can be used together or individually, thereby extending the life of the backlight module. 3. The backlight module of the present invention, in which the bottom light source is arranged on the bottom surface of the light guide plate, does not greatly increase the overall volume of the backlight module, and makes the liquid crystal

10333twf. Ptd Page 12 200420972 V. Description of the invention (9) The display can still maintain the characteristics of thin, light and short. Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some changes and retouch without departing from the spirit and scope of the present invention. The scope of protection of the invention shall be determined by the scope of the attached patent application.

10333twf.ptd Page 13 200420972 Brief Description of Drawings Figure 1 shows a schematic diagram of a conventional liquid crystal display; Figure 2 shows a schematic diagram of a liquid crystal display according to a preferred embodiment of the present invention; and Figure 3 shows It is a schematic enlarged sectional view at a range A in FIG. 2, which particularly shows the structure of the bottom light source. [Illustration of Graphical Symbols] 1 0 0: LCD 1 1 0 · LCD panel 1 2 0: Backlight module 1 2 2: Light guide plate 1 2 4: Side light source 1 2 6: Reflective cover 1 2 8: Frame 1 3 0: top surface 1 32: bottom surface 134: side surface 2 0 0: liquid crystal display 2 1 0 · liquid crystal panel 2 2 0: backlight module 2 2 2: light guide plate 2 2 4: side light source 2 2 6: reflection cover 228: Frame 2 3 0: diffuser

103331 wf.p td Page 14 200420972 Brief description of the drawings 232 Enhancement sheet 234 Bottom light source 236 Top surface 238 Bottom surface 240 Side 242 Transparent substrate 244 Anode 246 Organic functional layer 2 4 6 a: Hole injection layer 2 4 6 b: Hole conductive layer 2 4 6 c: Organic light emitting layer 2 4 6 d: Electron conductive layer 248: Cathode ❿

10333twf.ptd Page 15

Claims (1)

200420972 VI. Scope of patent application 1. A backlight module at least includes: a light guide plate having a top surface, a bottom surface and at least one side; a side light source, S has been placed beside the side of the light guide plate, wherein the The light provided by the side light source can enter the light guide plate from the side and pass through the bottom surface to the top surface and exit; and a bottom light source is arranged on the bottom surface of the light guide plate, wherein the light provided by the bottom light source is The light guide plate can be incident through the bottom surface and emitted from the top surface. 2. The backlight module according to item 1 of the scope of patent application, wherein the light guide plate is a wedge-shaped light guide plate. 3. The backlight module according to item 1 of the scope of patent application, wherein the bottom surface of the chirped light guide plate is a stepped surface for scattering the light provided by the side light source. 4. The backlight module according to item 1 of the scope of patent application, wherein the bottom surface of the light guide plate has a plurality of recesses to scatter the light provided by the side light source. 5. The backlight module according to item 1 of the scope of patent application, wherein the side light source is a cold cathode lamp. 6. The backlight module according to item 1 of the scope of patent application, wherein the bottom light source is an organic electro-optical light emitting element. 7. The backlight module according to item 6 of the scope of patent application, wherein the sense electromechanical excitation light element comprises: a transparent substrate; an anode formed on the transparent substrate; 10333twf. Ptd Page 16 200420972 6. Scope of Patent Application An organic functional layer is formed on the anode; and a cathode is formed on the organic functional layer. 8. The backlight module according to item 7 of the scope of patent application, wherein the organic functional layer comprises: a hole injection layer formed on the anode; a hole conduction layer formed on the hole injection layer An organic light emitting layer is formed on the hole conductive layer; and an electron conductive layer is formed between the organic light emitting layer and the cathode. 9. The backlight module according to item 6 of the scope of patent application, wherein the organic electro-optical light-emitting element comprises: a flat layer formed on the bottom surface of the light guide plate; Φ an anode formed on the flat layer An organic functional layer is formed on the anode; and a cathode is formed on the organic functional layer. 10. The backlight module according to item 9 of the scope of patent application, wherein the organic functional layer includes: a hole injection layer formed on the anode; a hole conduction layer formed on the hole injection layer Over; an organic light emitting layer formed on the hole conductive layer; and an electron conductive layer formed between the organic light emitting layer and the cathode. 1 1. The backlight module according to item 1 of the scope of patent application, further comprising a # reflector, which is disposed beside the side of the light guide plate to cover the side light source. 1 2. The backlight module described in item 1 of the scope of patent application, further comprising a 10333twf. Ptd Page 17 200420972 VI. Scope of Patent Application The frame is used to carry the light guide plate, the side light source and the bottom light source. 13. The backlight module according to item 1 of the scope of patent application, further comprising a diffusion sheet, which is disposed on the top surface of the light guide. 14. The backlight module according to item 13 of the scope of patent application, further comprising a light-increasing sheet, and the light-increasing sheet is disposed on the diffusion sheet. 15. A liquid crystal display including: a liquid crystal panel; a backlight module including: a light guide plate having a top surface, a bottom surface, and at least one side light source disposed on the side of the light guide plate, Wherein, the light provided by the color light source can enter the light guide plate through the side and pass through the bottom surface to the top surface and exit; and a bottom light source 'is disposed on the bottom surface of the light guide plate', where the bottom The light provided by the light source can enter the light guide plate through the bottom surface and exit from the top surface. 16. The liquid crystal display according to item 15 of the scope of patent application, wherein the light guide plate is a wedge-shaped light guide plate. 17. The liquid crystal display according to item 15 of the scope of patent application, wherein the bottom surface of the light guide plate is a stepped surface for scattering light provided by the side light source. 18. The liquid crystal display according to item 15 of the scope of patent application, wherein the bottom surface of the light guide plate has a plurality of recesses for scattering the light provided by the side light source. 19. The liquid crystal display according to item 15 of the scope of patent application, wherein 10333twf.ptd Page 18 200420972 6. Scope of patent application The side light source is a cold cathode lamp. 20. The liquid crystal display according to item 15 of the scope of patent application, wherein the bottom light source is an organic electro-optic light emitting element. 2 1. The liquid crystal display according to item 20 of the scope of patent application, wherein the organic electroluminescent element comprises: a transparent substrate; an anode formed on the transparent substrate; an organic functional layer formed on the Over the anode; and a cathode formed on the organic functional layer. 22. The liquid crystal display according to item 21 of the scope of patent application, wherein the organic functional layer includes: a hole injection layer formed on the anode; a hole conduction layer formed on the hole injection layer An organic light emitting layer formed on the hole conductive layer; and an electron conductive layer formed on the organic light emitting layer and the cathode layer 23 A display, wherein the organic electro-optic light-emitting element includes: a flat layer formed on the bottom surface of the light guide plate; an anode formed on the flat layer; an organic functional layer formed on the anode; and a A cathode is formed on the organic functional layer. 24. The liquid crystal display according to item 23 of the scope of patent application, wherein the organic functional layer includes: 10333twf .ptd Page 19 200420972 VI. Patent application scope A hole injection layer is formed on the anode; a hole conduction layer is formed on the hole injection layer; an organic light emitting layer is formed on the electrode Above the hole conducting layer: and an electron conducting layer formed between the organic light emitting layer and the cathode. 25. The liquid crystal display according to item 15 of the scope of patent application, further comprising a reflecting cover, which is arranged beside the side of the light guide plate to cover the side light source. 26. The liquid crystal display according to item 15 of the scope of patent application, further comprising a frame for carrying the light guide plate, the side light source and the bottom light source. 27. The liquid crystal display according to item 15 of the scope of patent application, further comprising a diffusion sheet, which is disposed on the top surface of the light guide. 28. The liquid crystal display according to item 27 of the scope of patent application, further comprising a light-enhancing sheet, the light-enhancing sheet being disposed on the diffusion sheet. 29. The liquid crystal display according to item 15 of the scope of patent application, wherein the liquid crystal panel is a transmissive liquid crystal panel or a transflective liquid crystal panel. 10333twf.ptd Page 20