WO2004059377A1

WO2004059377A1 - Direct-below backlight module

Info

Publication number: WO2004059377A1
Application number: PCT/CN2002/000934
Authority: WO
Inventors: Yi-Chun Ho
Original assignee: Quanta Display Inc.; Quanta Display Japan Inc.
Priority date: 2002-12-30
Filing date: 2002-12-30
Publication date: 2004-07-15
Also published as: AU2002357565A1; AU2002357565A8

Abstract

The present invention relates to a direct-below backlight module, including a plurality of light sources for irradiating light rays outwards; a reflective plate for reflecting the light rays irradiated by said plurality of light sources, one side of which has a plurality of slight arc shaped reflective grooves, the number of said slight arc shaped reflective grooves corresponding to that of said light sources and each of them half-surrounding the respective light source, and said slight arc shaped reflective grooves having a first reflective surface protruding upward in its central part, a second and third reflective surfaces in its left side part, and a same symmetrical structure in its right side part; a non-printed light-guiding plate for guiding light to travel upward, the side of which facing said plurality of light sources has a plurality of slight arc shaped transmissive grooves to disperse the light rays incident on it; and a covering case for covering and supporting the reflective plate and the light-guiding plate, while the transmissive side of the light-guiding plate is not covered by the covering case.

Description

Direct type backlight module TECHNICAL FIELD

The invention relates to a direct type backlight module for a liquid crystal display device, and in particular to a direct type backlight module having a plurality of light sources and a plurality of reflective curved surfaces corresponding to the number of light sources in a reflection cover. Background technique

In recent years, as the degree of integration of parts in various parts of computers has continued to increase, the requirements for peripheral products have continued to move toward light, thin, short, small, and low power requirements. Compared with other display devices, such as CRT, LCD is a device with small size and low power consumption. Since the liquid crystal molecules are not spontaneous light-emitting devices, the LCD requires a light source in addition to the liquid crystal display.

At present, the commonly used lamp sources for LCD screens are Cold Cathode Fluorescent Lamp-CCFL and Hot Cathode Fluorescent Lamp-HCFL. The most important component, the backlight module, is generally classified into two types: a direct part lighting type and an edge part lighting type according to the position of the light source. In the lower irradiation type, the irradiation light is homogenized by a diffusion sheet and then scattered into the liquid crystal panel. On the other hand, the side illumination type is first transformed into a sheet by a light guide plate (LGP., Light guiding plate). light source.

As shown in FIG. 1, a conventional lower illumination backlight module is shown. The lamp tube 10 is used as a light source and is surrounded by a reflector 20. It is used to reflect upward and homogenize the light emitted downward. An optical composite plate composed of a diffuser plate 50, a lower prism plate 60, and an upper prism plate 70 is laminated in this order.

The diffuser plate 50 is used to improve the incident light of the liquid crystal panel (not shown). The lower prism plate 60 and the upper prism plate 70 are used to change the route of light travel. They are composed of a series of sequential triangular grooves or hemispherical grooves. In order to protect the appearance of the lower prism plate 60 and the upper prism plate 70, A protective plate 80 is disposed on the upper prism plate 70, and a liquid crystal panel is disposed on the protective plate 80.

Each component of the above-mentioned backlight module is fixed on a mold frame 90 as a support Architecture, which is produced by an injection molding method. In addition, there are still four guide brackets (not shown in the figure) used as the assembly base of the four plates in the four corners of the mold frame 90, and each plate is fixed on the mold frame 90 through the guide frame. Similarly, the mold frame 90 also has a mounting hole (not shown) to fix the entire liquid crystal module in the display frame.

In the backlight module as described above, the light emitted from the lamp tube 10 is reflected through the reflection cover 20, and then the image on the display screen is revealed by the light passing through the diffusion plate 50, and the diffusion plate 50 is used to make The light is uniformized, and a specific selected angle is used to cause the light to pass through the lower and upper prisms 60 and 70 to change the course of travel and to shoot vertically toward the liquid crystal panel.

However, in order to have a good uniformity in the brightness of the screen in the backlight module, a certain distance must be maintained between the diffuser plate 50 and the lamp tube 10 to avoid light energy from being concentrated in certain specific areas. The brightness as shown in Figure 2 shows a situation of peaks and valleys. In the prior art, a layer of special printing ink (as shown in FIG. 3) is printed on the diffusion plate to disperse the energy of light, although this method can solve the problem of <1> poor uniformity and <2> It is easy to see the problem of the main body of the light source, but for the shortcomings of <3> increasing thickness and <4> decreasing screen brightness due to the need to maintain a certain distance between the diffuser plate and the lamp tube and the printing ink itself, and The life of printing inks is not long, and the problem of <5> screen yellowing caused by material changes still cannot be solved.

Therefore, in order to overcome the shortcomings mentioned above and take into account the thin and light weight of the backlight module, we need to develop a new structure to solve the poor uniformity of the screen of the direct type backlight module, easy to see the light source, low brightness, and the thickness cannot be Reduce problems such as yellowing of printing inks. Summary of the Invention

In order to overcome the defects caused by the conventional methods described above, the main object of the present invention is to provide an improved structure of the backlight module to achieve <1> improving the uniformity of the picture; <2> increasing the brightness; <3> reducing the thickness; And <4> the purpose of reducing dependence on printing inks.

Yet another object of the present invention is to provide a reflective base plate for a backlight module. According to the characteristics and angle of energy reflection of a light source, a specially designed reflective curved surface is used to effectively control the reflection angle of the light emitted by the light source, so that each light source generates The light energy can be evenly distributed to improve the uniformity of the picture. Yet another object of the present invention is to provide a reflective base plate for a backlight module, which can reduce the situation of mutual absorption of light energy between light sources through a specially designed reflective surface according to the characteristics and angle of energy reflection of the light source, and can effectively control the light source. The angle of the reflected light, thereby reducing the distance between the light source and the diffuser to reduce the thickness of the backlight module and increase the brightness of the screen.

Yet another object of the present invention is to provide a reflective base plate for a backlight module. According to the characteristics and angle of energy reflection of a light source, a specially designed reflective curved surface is used to effectively control the reflection angle of the light emitted by the light source, so that each light source is The light energy generated can be evenly distributed without using printing inks to achieve the required uniformity of the picture.

Another object of the present invention is to provide a non-printing light guide plate for a backlight module to replace the original diffuser plate. A rough layer having an atomizing effect and a light-transmitting material are used in the diffuser plate. Can take into account both the image uniformity and brightness.

Another object of the present invention is to provide a non-printing light guide plate for a backlight module to replace a diffusion plate that is originally used. Since a diffusion plate is not required, the distance between the light source and the diffusion plate can be shortened. This reduces the thickness and weight of the backlight module.

According to the above object, the present invention provides a direct type backlight module, the main structure of which includes a plurality of light sources for emitting light to the outside; a reflecting plate for reflecting light emitted from the plurality of light sources, and wherein One side has a plurality of slightly curved reflection grooves, and the reflection plate is arranged below the plurality of light sources. The number of the above-mentioned slightly curved reflecting grooves corresponds to a plurality of light sources, and each of the reflecting grooves surrounds its corresponding light source in a semi-circle, wherein, in the central part of each of the slightly curved reflecting grooves It has a first reflective surface protruding upward, a second reflective surface and a third reflective surface on the left edge portion of the reflective groove, and the right portion also has the same symmetrical structure; a non-printing type The light guide plate is used for guiding light to travel upwards, and a side of the light source facing the plurality of light sources has a plurality of light-transmitting grooves having a slightly arcuate shape for emitting light scattered to the light-transmitting grooves. Above, and tightly combined with the reflection plate located below the plurality of light sources to cover the plurality of light sources therein; and a covering cover for covering and supporting the reflection plate and the light guide plate, wherein the use of the light guide plate is The light-transmitting side is not covered by a cover.

The purpose and many advantages of the present invention will be fully disclosed through the detailed description of the following specific embodiments and with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

1 is a schematic diagram of a direct type backlight module in the prior art;

FIG. 2 is a schematic diagram of overlapping light energy;

3 is a schematic diagram of a diffusion plate with printing ink in the prior art;

4 is a schematic sectional view of a first embodiment of a direct type backlight module according to the present invention;

5 is a partially enlarged perspective view of a first embodiment of a direct type backlight module according to the present invention; FIG. 6 is an overall perspective view of a first embodiment of a direct type backlight module according to the present invention;

7 is a schematic cross-sectional view of a second embodiment of a direct type backlight module according to the present invention;

FIG. 8 is a partially enlarged perspective view of a second embodiment of a direct type backlight module according to the present invention; and FIG. 9 is an overall perspective view of a second embodiment of a direct type backlight module according to the present invention. detailed description

Some embodiments of the present invention will be described in detail below, in which different parts of the components are not drawn according to actual dimensions. The scale ratios of some scales to other parts are exaggerated to provide a clearer description to help those familiar with the art to understand the invention. First embodiment: '

As shown in FIG. 4, the light source 240 is placed above the reflection plate 250, and the light source 240 is a light tube 240 with a diameter Φ of about 2.6 mm (mm) and is located in the slightly curved shape of the reflection plate 250. In the reflection groove, it can be seen from the figure that the reflection groove surrounds the light source 240 in a semi-circle, and the central portion of the reflection groove has a first reflection surface 210 protruding upward in an arc shape, and the radius of curvature is about 2 to 3 times the diameter of the light source 240; the left edge portion of the reflection groove has a second reflection surface 220, the inclination angle of which is about 20 degrees to 40 degrees, preferably 30 degrees; and the third The reflecting surface 230 has an inclination angle of about 40 degrees to 70 degrees, preferably 60 degrees, and the right side portion also has the same symmetrical structure. Further, in FIG. 4 _h: 240 representative of the edge from the lowest point of the tube 210 to the highest point of the first reflecting surface, where 1 0 cm <^ <0/2; h ₂ representative of the center tube to the reflector 240. The distance from the bottom of the plate 250, where (Φ / 2) + ^ ≤¾ <(0/2) + 2h _{l 5} represents the radius of curvature of the reflection plate 250, where

R, χ Φ / 2) + (! ^ Can be changed according to design requirements>. When the light source 240 emits light outwards, the light traveling vertically downward directly below it can be appropriately reflected upward through the first reflecting surface 210 protruding upwardly without being blocked by the light source 240. The emitted light is reflected upward through other parts of the reflection groove. More specifically, the second reflection surface 220 and the third reflection surface 230 provided on the edge side of the present invention can pass light that cannot be properly reflected by the existing conventional light. These two specially designed reflecting surfaces appropriately reflect the light rays directed toward the edge of the reflecting groove upward to the diffuser plate.

Fig. 5 is a partially enlarged perspective view of the first embodiment. Fig. 6 is an overall oblique view of the first embodiment. Second embodiment:

Referring to FIG. 7, the initial structure and correlation coefficient are shown in FIG. 4 and FIG. 5, but in the second embodiment, a non-printing light guide plate 260 is provided on the light source 240 to replace the diffusion plate currently used. The curvature radius of the light guide plate 260 is, wherein, in this embodiment, the material of the non-printing light guide plate 260 is a transparent acrylic material, and a mask facing the light source 240 has a slightly arc-shaped penetration. The light groove is used to emit light scattered to the light-transmitting groove. The position of the light-transmitting groove corresponds to the reflection groove of the reflection plate 250. The combination of the two can cover the light source 240 therein. In addition, the connecting portion between the light-transmitting groove and the light-transmitting groove of the light guide plate 260 has a plurality of protruding portions 270 for reflecting a part of the refracted light generated when the light penetrates the light guide plate to reflect upward again. In addition, a plurality of rough layers 280 are provided on the other side of the light guide plate 260 having a plurality of light-transmitting grooves to diffuse the light passing through the light guide plate 260 to further evenly disperse the light and make the brightness of the screen more uniform.

FIG. 8 is a partially enlarged view of the second embodiment. Fig. 9 is an overall oblique view of the second embodiment.

The above are only preferred embodiments of the present invention, and are not intended to limit the scope of patent application of the present invention; all other equivalent changes or modifications made without departing from the spirit disclosed by the present invention should be included in the scope of patent application described below . Main component number

10 tubes

20 reflector Upper prism protection plate mold plate under diffuser prism

First reflective surface Second reflective surface Third reflective surface Light source Reflective plate Light guide tube Projection Rough layer Light guide plate

Claims

Claim

1. A direct type backlight module, comprising:-a plurality of light sources emitting light to the outside;

A reflecting plate having a plurality of arc-shaped reflecting grooves on one side thereof, the reflecting plate is disposed below the plurality of light sources, and the number of the arc-shaped reflecting grooves corresponds to a plurality of light sources and each of the An arc-shaped reflection groove surrounds its corresponding light source in a semi-circle, wherein a central portion of each of the arc-shaped reflection grooves has a first reflection surface protruding upward, and a left edge portion of the groove Has a second reflecting surface and a third reflecting surface, and the right side portion also has a same symmetrical structure; and, 'a covering cover covering and supporting the reflecting plate, wherein the reflecting plate has One side of the arc-shaped reflection groove is not covered by a cover.

2. The direct-type backlight module according to claim 1, wherein a curvature radius of the reflecting plate XΦ / 2) +, where ^ is a distance from the lowest point of the lower part of the light source to the highest point of the first reflecting surface, and Φ is Light source diameter.

The direct-type backlight module according to claim 2, wherein a curvature radius of the upwardly protruding first reflecting surface is 2 to 3 times a diameter of the light source Φ.

The direct-type backlight module according to claim 3, wherein the inclination angle of the second reflecting surface is between 20 degrees and 40 degrees.

The direct-type backlight module according to claim 4, wherein an inclination angle of the third reflection surface is between 40 degrees and 70 degrees.

6. The direct-type backlight module according to claim 5, wherein the distance between the arc-shaped groove and its corresponding light source is ^: 1. 0 wake <^ <0/2.

The direct-type backlight module according to claim 6, wherein the radius h ₂ of the arc-shaped reflection groove has a value of: (Φ / 2) + ^ ≤¾ <(0/2 ) + 2¾.

The direct-type backlight module according to claim 1, further comprising: a non-printing light guide plate for guiding light to travel upward, a side of the light source facing the plurality of light sources has a plurality of arc-shaped The light-transmitting groove is configured to emit light scattered to the arc-shaped light-transmitting groove, and the light-transmitting groove is disposed above a plurality of light sources and is closely connected to the reflection plate located below the plurality of light sources. Combined to enclose the plurality of light sources therein; and The covering cover covers and supports the light guide plate, wherein the light-transmitting side of the light guide plate is not covered by the covering cover.

9. The direct type backlight module according to claim 8, wherein each of the connecting portions of each of the arc-shaped light-transmitting grooves has a plurality of light-transmitting light generated by penetrating the light guide plate. 10. Part of the refracted light is reflected upward again at the raised part.

The direct-type backlight module according to claim 8, wherein a plurality of light diffused through the light guide plate are provided on the other side of the light guide plate having a plurality of arc-shaped light-transmitting grooves. 11. Rough layer.