CN103162161B - Backlight module and liquid crystal display device - Google Patents

Abstract

The invention discloses a backlight module, which comprises a lower iron frame, a light source group arranged in the lower iron frame, a light guide plate and an optical film group, the optical film group is located above the light guide plate, the The light source group includes a PCB and LEDs arranged on the PCB, the LEDs are located on both sides of the light guide plate, and the PCB is used to fix the optical film group and the liquid crystal panel. The invention omits the plastic frame, and directly uses the PCB of the light source group to fix the optical film group and the liquid crystal panel, thereby saving the mold cost, reducing the thickness of the backlight module group, and simplifying the assembly steps.

Description

Backlight module and liquid crystal display device

technical field

The invention relates to the field of liquid crystal display manufacture, in particular to a backlight module and a liquid crystal display device.

Background technique

Liquid crystal display (LCD) uses the change of the electric field strength clamped on the liquid crystal molecules to change the orientation of the liquid crystal molecules to control the intensity of light transmission to display images. Generally speaking, a complete liquid crystal display panel must have a backlight module, a polarizer, a thin-film transistor (TFT) lower substrate, a color filter (CF) upper substrate, and a liquid crystal molecule layer filled in a box composed of two substrates. . The liquid crystal display is a passive light-emitting display device, that is to say, the liquid crystal substrate itself cannot emit light, and the light source needs to be provided by the backlight module. The backlight module is generally composed of a backplane, a light source, a diffusion plate and various optical films.

Generally, the backlight module is divided into direct type and edge type according to the position of the light source. The light source of the direct-type backlight module is located at the bottom of the backlight module. The light utilization rate of the light source of the direct-type backlight module is relatively high, but the light of the direct-type light source will form an alternating light and dark area, so a diffuser with a high haze is required. Board and larger light box distance to solve this problem, increasing the thickness of the backlight module. The light source of the side-light backlight module is located on one side of the backlight module, and the light emitted by the light source is converted into a surface light source through the light guide plate to meet the brightness and uniformity requirements. The side-light backlight module The light utilization rate is relatively low, but it has the advantages of simple process, light and thin volume.

Please refer to FIG. 1 , which is a schematic cross-sectional structure diagram of an existing edge-lit backlight module. The backlight module includes a light source group 11 , a lower iron frame 16 , a reflector 12 , a light guide plate 13 , and a plastic frame 14 And the optical film 15, the plastic frame 14 is assembled on the lower iron frame 16, and then the optical elements, such as the reflector 12, the light source group 11, the light guide plate 13, and the optical film 15 are installed in the plastic frame 14 and fixed . As far as the backlight module is concerned, the lower iron frame 16 is to provide the function of the backlight module and its structural strength, while the plastic frame 14 is used to place and fix optical components such as reflectors 12, light source groups 11, light guide plates 13, A plurality of optical films 15.

At present, most LCD screens use CCFL (Cold Cathode Fluorescent) backlight modules. Due to the limitation of CCFL's luminous characteristics, LCD TVs using CCFL backlight modules have poor color reproduction. With the development of LED (light-emitting diode) technology, LED is gradually applied to the backlight module of LCD display. The light source provided by LED backlight module has the advantages of good color reproduction, high contrast, high brightness and fast light control speed. . As shown in Figure 2, the Chinese patent application with the application number 200920049769.7 discloses a backlight module, which includes a metal protective frame 1, a reflection sheet 2, a light guide plate 3, and a diffusion sheet assembled sequentially from the back to the front. 4. The lower brightness enhancement sheet 5, the upper brightness enhancement sheet 6 and the light-shielding sheet 7. The side of the light guide plate is provided with an LED light source assembly, and the LED light source assembly is composed of a number of LED lamps connected in series. A light string 8 and a flexible circuit board 9 by welding, and a plastic frame 10 is installed under the LED light source assembly.

However, as far as the overall structure of the backlight module is concerned, optical components are indispensable. Therefore, in order to reduce costs, other components must be considered to replace the original plastic frame so that it has the ability to place and fix the original plastic frame. Component structure and function. Therefore, how to use other components to replace the plastic frame of the backlight module is really a difficult problem to be overcome by the relevant industry.

Contents of the invention

The object of the present invention is to provide a backlight module and a liquid crystal display device, so as to save mold costs, reduce the thickness of the backlight module, and simplify assembly steps.

In order to solve the above technical problems, the present invention provides a backlight module, which includes a lower iron frame, a light source group, a light guide plate and an optical film group arranged in the lower iron frame, and the optical film group is located in the guide Above the light plate, the light source group includes a PCB and LEDs arranged on the PCB, the LEDs are located on both sides of the light guide plate, and the PCB is used to fix the optical film group and the liquid crystal panel.

Optionally, in the backlight module, a through hole is opened on the PCB, the optical film set has an ear portion, and the ear portion of the optical film set is accommodated in the through hole.

Optionally, the backlight module further includes a buffer disposed between the PCB and the liquid crystal panel. The buffer is a gel strip.

Optionally, in the backlight module, the thickness of the PCB is 3mm-10mm.

Optionally, the backlight module further includes a reflective sheet, the reflective sheet is arranged in the lower iron frame, and the light guide plate is arranged on the reflective sheet.

Optionally, the backlight module further includes an upper iron frame, the upper iron frame covers the liquid crystal panel and covers the side wall of the lower iron frame.

According to another aspect of the present invention, a liquid crystal display device is also provided, including a liquid crystal panel and the above-mentioned backlight module.

Compared with the prior art, the backlight module of the present invention omits the plastic frame, which directly uses the PCB of the light source group to fix the optical film group and the liquid crystal panel, thereby saving mold costs and reducing the thickness of the backlight module. And the assembly steps can be simplified.

Description of drawings

FIG. 1 is a schematic cross-sectional structure diagram of an existing backlight module;

FIG. 2 is a schematic cross-sectional structure diagram of another existing backlight module;

3 is a schematic cross-sectional structure diagram of a backlight module according to an embodiment of the present invention;

FIG. 4 is an enlarged schematic view of a backlight module according to an embodiment of the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and use imprecise ratios, which are only used to facilitate and clearly assist the purpose of illustrating the embodiments of the present invention.

The core idea of the present invention is to provide a backlight module without a plastic frame. The backlight module uses the PCB of the light source group to fix the optical film group and the liquid crystal panel, thereby saving mold costs, reducing the thickness of the backlight module, and Assembly steps can be simplified.

Please refer to FIG. 3 and FIG. 4 for details, wherein FIG. 3 is a schematic cross-sectional structure diagram of a backlight module according to an embodiment of the present invention, and FIG. 4 is an enlarged schematic diagram of the backlight module according to an embodiment of the present invention. The backlight module includes a lower iron frame 21, a light source group arranged in the lower iron frame 21, a light guide plate 22 and an optical film set 23, the optical film set 23 is located above the light guide plate 22, and the The light source group includes a PCB (Printed Circuit Board, printed circuit board) 25 and an LED (Light Emitting Diode, light emitting diode) 24 arranged on the PCB 25, the LED 24 is located on both sides of the light guide plate 22, and the PCB 25 is used to fix the optical film group 23 and the liquid crystal panel 27 .

In this embodiment, the PCB 25 is provided with a through hole 251, the optical film set 23 has an ear portion 231, and the ear portion 231 of the optical film set 23 is accommodated in the through hole 251, so It can prevent the optical film group 23 from shaking, and prevent the optical films from rubbing against each other to affect the display quality. Of course, in other embodiments of the present invention, the PCB 25 may not provide a through hole, but only provide a groove, which can also achieve the purpose of fixing the optical film group 23. Or, the optical film group 23 and the liquid crystal panel 27 can also be directly placed on the top of the PCB 25 successively, and the optical film group 23 and the liquid crystal panel 27 can be fixed equally.

Preferably, the size of the through hole 251 is slightly larger than the thickness of the optical film set 23, so that even if the optical film set 23 expands with heat and contracts with cold, it can still ensure that it has enough space to accommodate the optical film. Sheet group 23. Preferably, the gap on one side of the optical film group 23 is 0.2mm˜0.5mm.

Wherein, the PCB 25 can be an aluminum-based PCB board, the light guide plate 22 can be a thin light guide plate produced by injection molding mold pressurization technology, and the light emitted by the LED 24 passes through the light guide plate 22 to convert the line light source into a surface light source to meet brightness and uniformity requirements.

Further, the backlight module also includes a buffer 29 arranged between the PCB 25 and the liquid crystal panel 27, the buffer 29 can play a buffering role when the liquid crystal display device is subjected to a drop impact test, to avoid liquid crystal Panel 27 is damaged. The buffer 27 is preferably a rubber strip, which can not only play a buffering role, but also fix the liquid crystal panel 27 by utilizing the stickiness of the rubber strip. Of course, the present invention does not limit the material of the buffer 27, and other soft materials that can play a buffering effect are within the protection scope of the present invention. For example, the buffer 29 can also be made of rubber and other materials.

Preferably, the thickness of the PCB 25 is 3 mm to 10 mm. On the one hand, it can ensure that it is sufficient to carry the liquid crystal panel and the optical film group, and on the other hand, it will not increase the weight of the entire backlight module due to being too thick.

Optionally, the backlight module further includes a reflective sheet 28 , the reflective sheet 28 is disposed in the lower iron frame 21 , and the light guide plate 22 is disposed on the reflective sheet 28 .

In addition, the backlight module can also include an upper iron frame 26 , the upper iron frame 26 covers the liquid crystal panel 27 and covers the side wall of the lower iron frame 21 , by means of the upper iron frame 26 The shielding function of the optical film group 23 will not be damaged by external influences.

Continuing to refer to Fig. 3 and Fig. 4, the assembly process of the backlight module is as follows: first, the light source group, the light guide plate 22 and the optical film group 23 are installed in the lower iron frame 21, and the optical film group 23 The ear part 231 is fixed in the through hole 251 of the PCB 25, and then the liquid crystal panel 27 is placed on the PCB 25, and the optical diaphragm group 23 and the liquid crystal panel 27 are protected by means of the upper iron frame 26. Compared with the prior art, the present invention omits the plastic frame, and uses the PCB 25 of the light source group to fix the optical film group 23 and the liquid crystal panel 27, which saves mold costs, reduces the thickness of the backlight module, and simplifies the assembly steps .

According to another aspect of the present invention, there is also provided a liquid crystal display device, which includes a liquid crystal panel and the above-mentioned backlight module.

Although the above embodiments have described the present invention in detail, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (8)

1. a backlight module, it is characterized in that, comprise lower chase and be arranged at light source group, light guide plate and the optical diaphragm group in described lower chase, described optical diaphragm group is positioned at above described light guide plate, described light source group comprises PCB and is arranged at the LED on described PCB, described LED is positioned at the both sides of described light guide plate, and described PCB is in order to fixing described optical diaphragm group and liquid crystal panel.

2. backlight module as claimed in claim 1, it is characterized in that, described PCB offers through hole, and described optical diaphragm group has ear portions, and the ear portions of described optical diaphragm group is contained in described through hole.

3. backlight module as claimed in claim 1, is characterized in that, also comprise the cushion be arranged between described PCB and liquid crystal panel.

4. backlight module as claimed in claim 3, it is characterized in that, described cushion is adhesive tape.

5. as the backlight module in Claims 1-4 as described in any one, it is characterized in that, the thickness of described PCB is 3mm ~ 10mm.

6. as the backlight module in Claims 1-4 as described in any one, it is characterized in that, described backlight module also comprises a reflector plate, and described reflector plate is arranged in described lower chase, and described light guide plate is arranged on described reflector plate.

7. as the backlight module in Claims 1-4 as described in any one, it is characterized in that, described backlight module also comprises chase on, and described upper chase to be covered on described liquid crystal panel and to be coated on the sidewall of described lower chase.

8. a liquid crystal indicator, is characterized in that, comprises liquid crystal panel and the backlight module according to any one of claim 1 to 7.