JP2005025979A - Backlight module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a backlight module whereby a bleed through phenomenon is prevented from occurring. <P>SOLUTION: This backlight module is positioned under a display panel, and is composed of a light dispersion plate, at least one light source, a prism, a light guide plate (LGP), at least one light shielding sheet, and a reflecting sheet. The light source emits light, and the light dispersion plate is placed between the light source and the display panel. The prism is placed on the surface of the light dispersion plate, and the light guide plate is placed between the light source and the light dispersion plate. The light guide plate guides light to the light dispersion plate by dispersing it, and the light dispersion plate irradiates light to the display panel by further dispersing it. The reflecting sheet reflects light from the light source toward the upper side, and irradiates it to the light guide plate. The light shielding sheet is a translucent sheet, and is placed between the light source and the light guide plate. It has a plurality of holes for light to pass through. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a backlight, and more particularly to a backlight that prevents a bleed-through phenomenon.
[0002]
[Prior art]
The backlight unit is a well-known technique. A backlight unit, which is a key component of a liquid crystal display device, is widely used in digital cameras, PDAs (portable personal information terminals), automobile navigation systems, computer monitors, flat panel televisions, and the like. In particular, a backlight unit that is usually installed immediately behind the display panel includes a light source (may be a plurality of light sources) and a means for dispersing light. This is because the dispersive means widely disperses the light and provides the user with comfortable back lighting. The light is transmitted through the display panel thereabove and forms various images controlled by pixel electrodes arranged in a high density on the display panel. Backlight units can be classified mainly into two types. It is an edge light source type and a direct type. The direct backlight unit is suitable for a large display panel or a display panel of a television because the light is stronger than the edge light source backlight unit.
FIG. 1 is a cross-sectional view of a backlight module 10 according to the prior art. As shown in FIG. 1, the backlight module 10 is below the display panel 12 and includes at least one light source 14 and a light dispersion plate 16. The light dispersion plate 16 is disposed between the light source 14 and the display panel 12. It is in. A light guide plate (LGP) 18 is located between the light source 14 and the light dispersion plate 16. The reflection sheet 20 is below the light source 14 and is fixed to the housing 22.
The light source 14 emits light, and the reflection sheet reflects the light from the light source 14 upward, thereby increasing the light use efficiency of the backlight module 10. The light guide plate 18 disperses the light and guides it to the light dispersion plate 16, and the light dispersion plate 16 further disperses the light and applies it to the display panel 12. The housing 22 having the reflection sheet 20 disposed on the lower surface is assembled by the light dispersion plate 16, the light guide plate 18, the reflection sheet 20 and the light source 14. Further, the light dispersion plate 16 includes at least one prism 24 placed on the surface of the light dispersion plate 16 so as to reduce intensity unevenness of light entering the display panel 12. The number and placement of the prisms 24 are determined by the specifications of the backlight module 10.
Normally, the light source 14 is a cold cathode fluorescent lamp (CCFL), and a plurality of light sources 14 are arranged in parallel. Due to technological advances, the brightness of the light source 14 is becoming increasingly brighter to meet market demands. However, as the brightness of the light source 14 is improved, light fringes often appear on the display panel 12. This causes an imbalance on the display panel 12, which is called a bleed-through phenomenon. In addition, this bleed-through phenomenon may cause functional defects of the display panel 12 due to the long-time operation of the backlight module 10, resulting in poor product competitiveness.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a backlight module that prevents a bleed-through phenomenon as described in the description of the prior art.
[0007]
[Means for Solving the Problems]
According to the invention, the backlight module is under the display panel, and includes a light dispersion plate, at least one light source, a prism, a light guide plate (LGP), at least one light shielding sheet and a reflection sheet. ing. The light source emits light, and the light dispersion plate is placed between the light source and the display panel. The prism is placed on the surface of the light dispersion plate, and the light guide plate is placed between the light source and the light dispersion plate. The light guide plate disperses light and guides it to the light dispersion plate, and the light dispersion plate further disperses the light and applies it to the display panel. The reflection sheet reflects light from the light source upward and strikes the light guide plate. The light shielding sheet is a translucent sheet and is placed between the light source and the light guide plate and has a plurality of holes through which light passes.
In this invention, the light from the light source is scattered through a plurality of holes in the light shielding sheet and sent to the light guide plate, so that it becomes uniform scattered light, and this invention prevents the bleed-through phenomenon. There is an advantage of doing. When the light shielding sheet is a translucent sheet, there is no need for a hole through which light passes in order to simplify the manufacturing process of the backlight module. By using a light shielding sheet for the backlight module, the display quality is improved and the product is competitive.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 2 shows a cross-sectional view of the backlight module 40 according to the present invention. As shown in FIG. 2, the backlight module 40 is under the display panel 42, and has at least one light source 44, a light dispersion plate 46 between the display panel 42 and the light source 44, and a surface of the light dispersion plate 46. At least one prism 48, a light guide plate (LGP) 50 between the light source 44 and the light dispersion plate 46, at least one light shielding sheet 52 between the light source 44 and the light guide plate (LGP) 50, a light source The reflective sheet 54 is located under the reflective sheet 54, and the casing 56 wraps the reflective sheet 54 under the reflective sheet 54.
As shown in FIG. 2, the light source 44 uses lamps arranged in parallel to supply light. In the preferred embodiment of the invention, the light source 44 is a cold cathode fluorescent lamp (CCFL). The reflection sheet 54 is made of aluminum (Al) or a metal alloy, and dissipates heat generated by the operation of the backlight module 40. Therefore, the reflection sheet 54 has at least one opening 58, and the light reflected by the reflection sheet 54 is a light shielding sheet. 52 and the light guide plate 50. In another embodiment of the present invention, the reflection sheet 54 is made of a laminated film, the upper film is a metal film or other material having high light transmittance, and the lower film is foamed polyethylene terephthalate (foamed PET). Or it consists of polycarbonate (PC).
The light guide plate 50 disperses the light 45 emitted from the light source 44, sends it to the light dispersion plate 46, further disperses it by the light dispersion plate 46, and sends it to the display panel 42. In a preferred embodiment of the present invention, the light shielding sheet 52 and the light guide plate 50 are simultaneously formed by an injection molding method. Of course, the light shielding sheet 52 and the light guide plate 50 may be made separately and bonded with an adhesive. The prisms 48 on the surface of the light dispersion plate 46 prevent unevenness in the light intensity of the display panel 42. The number and placement of the prisms 48 are determined by the specifications of the backlight module 40. The casing 56 has a plurality of heat exhaust ports 60 to dissipate heat generated during operation of the backlight module 40.
FIG. 3 is an enlarged schematic view of the light shielding sheet 52 shown in FIG. As shown in FIG. 3, the light shielding sheet 52 has an arc shape and can cover the plurality of light sources 44, and the light guide plate 50 has a curved surface corresponding to the arc shape of the light shielding sheet 52. Further, the light shielding sheet 52 includes a hole 62 through which a plurality of lights pass, and scatters the light 45 from the light source 44 or the light 45 reflected by the reflection sheet 54, as shown by arrows in FIG. Guide to the light guide plate 50. Usually, the light shielding sheet 52 is made of a translucent sheet or a metal sheet. When the light shielding sheet 52 is made of a translucent sheet, the holes 62 through which a plurality of lights pass can be omitted. When the light shielding sheet 52 is made of a metal sheet, the light shielding sheet 52 serves to send the light 45 from the light source 44 to the reflection sheet 54. The light 45 reflected upward by the reflection sheet 54 is sent to the light guide plate 50 as shown by an arrow in FIG.
As mentioned in the previous prior art section, as technology advances, the brightness of the light source will improve more and more to meet market demands, the display during operation of the backlight module The panel 12 sometimes had a light stripe called a bleed-through phenomenon. This is due to an imbalance in the brightness of light from the light source. It has been clarified that the light shielding sheet 52 in this invention can prevent the bleed-through phenomenon. Compared with the prior art, the light 45 from the light source 44 in the present invention passes through the hole 62 through which the light of the light shielding sheet 52 passes, and is guided to the light guide plate 50 to become uniform light. Can be prevented. When the light shielding sheet 52 is translucent, the hole 62 through which light passes may be omitted in order to simplify the production process of the backlight module 40. By using the light shielding sheet 52 for the backlight module 40, the display quality is improved and the product is competitive.
Any modification or change that can be made by a person skilled in the art, which is made within the spirit of the present invention and has an equivalent effect on the present invention, belongs to the scope of the claims of the present invention. It is.
[0015]
【The invention's effect】
In this invention, the light from the light source is scattered through the plurality of holes of the light shielding sheet and sent to the light guide plate, so that it becomes uniform scattered light, and this invention has the advantage of preventing the bleed-through phenomenon. There is. When the light shielding sheet is a translucent sheet, there is no need for a hole through which light passes in order to simplify the manufacturing process of the backlight module. By using a light shielding sheet for the backlight module, the display quality is improved and the product is competitive.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a conventional backlight module.
FIG. 2 is a cross-sectional view of a backlight module according to the present invention.
3 is an enlarged schematic view of the light shielding sheet 52 in FIG. 2. FIG.
[Explanation of symbols]
10, 40, backlight modules 12, 42, display panels 14, 44, light sources 16, 46, light dispersion plates 18, 50, light guide plate (LGP)
20, 54, reflection sheets 22, 56, casings 24, 48, prism 45, light 52, light shielding sheet 58, opening 60, heat exhaust port 62, hole through which light passes.

Claims (10)

At least one light source for supplying light in a backlight module under the display panel, a light dispersion plate that is placed between the light source and the display panel and disperses light toward the display panel, and a surface of the light dispersion plate A prism placed on the light source, a light guide plate placed between the light source and the light dispersion plate to disperse light and lead to the light dispersion plate, at least one light shielding sheet placed between the light source and the light guide plate, A backlight module comprising a reflective sheet underneath that reflects light toward the light guide plate. The backlight module according to claim 1, further comprising a casing under the reflection sheet so as to wrap the reflection sheet. The backlight module according to claim 1, wherein the reflective sheet has at least one opening for dissipating heat generated during operation of the backlight module. The backlight module according to claim 1, wherein the light source is a lamp. The backlight module according to claim 4, wherein the lamps are arranged in parallel. The backlight module according to claim 1, wherein the light shielding sheet has an arc shape. The backlight module according to claim 6, wherein the light shielding sheet is a translucent sheet. The backlight module according to claim 6, wherein the light shielding sheet includes a hole through which a plurality of lights pass. 9. The backlight module according to claim 8, wherein the light shielding sheet is a reflection film for reflecting light to the reflection sheet, and light is further transmitted from the reflection sheet to the light guide plate. The backlight module according to claim 9, wherein the reflection sheet is a metal sheet.

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