JPH0968703A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent luminance from getting partially higher due to unwanted reflection by partially or wholly applying reflection prevention precessing to a housing body. SOLUTION: Light emitted from a fluorescent tube 50 enters a light guiding member 40. Though the light a1 out of the light impinges on a surface 13a, it does not reach a viewer because the reflection prevention processing is applied to the surface 13. On the other hand, the light a5 passes a diffusing member 70, a light collecting member 72 and a liquid crystal panel 30 after it is reflected by the reflection part 42 of the bottom part of the member 40, and reaches the viewer. The light a3 which reaches an end part on an opposite side to the fluorescent tube 50 and is transmitted through the member 40 is cast to the surface 16 of the houding body 20 to which the reflection prevention processing is applied and it does not reach the viewer. The light a4 shines to the surface 15 of the housing body 20 to which the reflection prevention processing is applied and does not reach the viewer. By applying black reflection prevention processing to the housing body in such a way, the luminance is prevented from getting partially higher due to the reflection, and then the device having excellent display quality where irregular luminance is restrained is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device using an illuminating device that illuminates a liquid crystal panel from the back side.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices, which are small and convenient for portability, have been used in various fields as seen in small portable televisions, small portable monitors, portable game consoles, and the like. Under such circumstances, various liquid crystal display devices have been proposed.

Conventionally, Japanese Unexamined Patent Publication No. 64-515, Japanese Utility Model Laid-Open No. 2
As disclosed in Japanese Patent Application Laid-Open No. 78-92626 and Japanese Patent Application No. 4-324821, a liquid crystal device is configured to provide illumination for clearly displaying an image displayed on the liquid crystal panel to a liquid crystal panel having at least a function as a passive element. Device or a liquid crystal display device represented by a video signal or the like, a circuit board having a signal processing circuit for converting an electric signal input or received from an external signal source into a liquid crystal panel drive signal, or a frame and a liquid crystal for housing the member. And a panel.

As a liquid crystal display device having a built-in lighting device, for example, a direct light system in which a fluorescent tube is arranged on the back surface of a liquid crystal panel, and a lighting device in which a light guide member is arranged under a liquid crystal panel and a side surface of the light guide member is provided. It is roughly divided into the arranged edge light system.

The present application can be applied to an edge light type and a direct light type illumination method, but is particularly effective when an edge light type illumination device is used. As a conventional example of an edge light type liquid crystal display device, Japanese Patent Application Laid-Open No. 4-3
It is described in detail in the 24821 publication and the like.

A conventional technique of an edge light type liquid crystal display device will be described with reference to FIG. A conventional technique will be described with reference to FIG. 3, which is a cross-sectional view of a main part in a cross-sectional view in which the drive IC 34 of the common electrode of the liquid crystal display device is cut and the liquid crystal panel 30 is cut along the wiring of the common electrode. FIG.
In this case, the fluorescent tube 50 as a light source is disposed in the housing 90, and the fluorescent tube 5 is provided between the side portion of the fluorescent tube 50 and the housing 90.
A reflection sheet 60 for reflecting the light of 0 toward the light guide member 40 is arranged, but a container 90 for housing the fluorescent tube 50.
There is a case where the surface of is colored with a light reflection color, for example, white or silver.
As the reflection sheet, for example, an aluminum vapor deposition film of polyester or a sheet having a light reflection function by coloring in white is used. Housing 90 for the fluorescent tube 50
The light guide member 40 is disposed on the side surface of the fluorescent tube 50 on the opposite side. The light guide member 40 may be formed by laminating a large number of transparent plate-shaped bodies made of acrylic resin on each other, or may be formed by a single acrylic plate. The diffusion member 7 is provided on the light guide member 40.
0 is allocated. Depending on the specification conditions, a light collecting member 72, which is a prism sheet for collecting the diffused light, is provided above the light diffusing member 70. For the light diffusion member 40, a milky white or translucent acrylic plate is used. Above the light collecting member 72, the polarization member 32, the driving IC 34, and the FP
A liquid crystal panel 30 including a C (flexible printed circuit board) 36 is provided. Further, the liquid crystal panel 30 is stored in the storage body 90.
In order to support the liquid crystal display device, a liquid crystal display device is completed by disposing a front surface support member 85 above the liquid crystal panel 10 and engaging the housing 90 and the front surface support member with hooks. Although a metal plate is molded as the front surface supporting member 85, an ABS material, a PS (vinyl chloride) material, or a P material which is a resin material is used.
A C (polycarbonate) material is molded.

The operation of the light shown in FIG. 3 will be described.
The light emitted from the light enters the light guide member 40, then exits from the light exit surface 41, and enters the light diffusion member 70. Fluorescent tube 5
A part of the light emitted from 0 is reflected by the reflection sheet 60 disposed on the side opposite to the light guide member 40 and enters the light guide member 40. Further, a part of the light incident on the light guide member 40 is reflected toward the light emission surface 41 by the reflection portion 42 provided on substantially the entire bottom surface of the light guide member 40. The light emitted from the light emitting surface 41 of the light guide member 40 is diffused by the diffusion member 7.
The light which is diffused by 0 and is substantially uniform by the light collecting member 72 is incident on substantially the entire surface of the liquid crystal panel 10 having the polarizing member 32. The light incident on the liquid crystal panel 30 is controlled to form an image such as a character or an image and enters the eyes of a person who views the liquid crystal display device.

[0008]

When the image of the conventional liquid crystal display device described with reference to FIG. 3 is viewed by the viewer 80, the periphery of the screen is brighter than the central part of the screen, and uneven brightness of the screen occurs, which is difficult to see. There is a problem. When the cause of the brightness unevenness is investigated, the light from the light guide member 40 as shown in FIG.
The light a2 reflected by the surface 0 of 0 passes through the arrow and the viewer 80
To reach. Similarly, the light reflected on the surface 92 and the surface 9
The light a1 reflected by 1 reaches the viewer 80 through the arrow. Similarly, on the side portion of the housing 90 facing the side where the fluorescent tube 50 is disposed, the light a4 reflected by the surface 95 of the housing 90 passes through the arrow, similarly to the surfaces 91 and 92. Since the light a3 that reaches the viewer 80 and is reflected by the surface 96 reaches the viewer 80 through the arrow, it was found that the brightness around the screen became bright and the display quality was deteriorated. .

An object of the present invention is to provide a liquid crystal display device which solves the above-mentioned problems, suppresses uneven brightness due to reflection, and has improved display quality.

[0010]

In order to solve the above problems, according to the present invention, in a liquid crystal display device having a container, light emitted from the light guide member is stored in the container. It is characterized in that it has a window that leads to the above, and that at least the surface of the window, the adjacent surface, and the peripheral surface are subjected to antireflection treatment.

Further, in a liquid crystal display device having a housing, the housing comprises an upper housing and a lower housing, and at least the upper housing receives the light emitted from the light guide member. It is characterized in that it has a window leading to the liquid crystal panel, and at least the surface of the window portion, the adjacent surface, and the peripheral surface are subjected to antireflection treatment.

Further, the antireflection treatment is black treatment.

Further, the antireflection treatment is a gray treatment.

The antireflection is a satin finish.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a main part of a liquid crystal display device using an edge light type lighting device according to a first embodiment of the present invention, namely, a lighting device, a housing and a liquid crystal panel. It is an explanatory perspective view showing a relationship. FIG. 2 is a cross-sectional view of the liquid crystal display device using the edge light type illumination device according to the first embodiment of the present invention, in which the common electrode drive IC is cut and the liquid crystal panel is cut in parallel with the wiring of the common electrode. It is a principal part sectional drawing in a figure.

The same members as those in the conventional example are denoted by the same reference numerals as those used in the present embodiment. In FIG. 1, the storage unit is composed of a lower storage unit 29 and an upper storage unit 28, and each storage unit has a window 27 for guiding light from the light guide member 40 to the liquid crystal panel 30, Lower storage 29
The illumination device includes a fluorescent tube 50 which is a light source, and a reflection sheet 60 for reflecting the light of the fluorescent tube 50 toward the light guide member 40 between the side portion of the fluorescent tube 50 and the lower housing 29. However, the surface of the lower housing body 29 that houses the fluorescent tube 50 may be a light reflection color, for example, white or silver, and the lower housing body 29 is partially molded by molding a white resin material. It is more preferable that the reflection process can be eliminated and the reflection sheet 60 can be deleted. As the illuminating device, in addition to the above-mentioned members, a light amount adjusting member for adjusting the light amount by a plate having a pattern printed in black on a transparent plate, a diffusing member, and a light collecting member are appropriately combined and used, but they are omitted in FIG. . As the reflection sheet, for example, an aluminum vapor deposition film of polyester or a sheet having a light reflection function by coloring in white is used.
The fluorescent tube 50 on the side opposite to the lower container 29 with respect to the fluorescent tube 50
The light guide member 40 is disposed on the side surface. The light guide member 40 may be formed by laminating a large number of transparent plate-shaped bodies made of acrylic resin on each other, or may be formed by a single acrylic plate. A diffusing member is disposed above the light guide member 40. Further, depending on the specification conditions, a light collecting member which is a prism sheet for collecting the diffused light is arranged above the diffusing member, but it is omitted in FIG. For the light diffusion member 40, a milky white or translucent acrylic plate is used. The upper housing 28 is disposed above the light collecting member 72 and the light guide member 40 as shown in FIG. The upper housing 28 is formed of a black or gray resin material that suppresses light reflection. Therefore, the light a11, a21, a31, b11, b21 is struck by the light from the light guide member 40 on the window portion surface of the window 27, the peripheral surface and the adjacent surfaces 21, 22, 23, 24, 25, 26. At this time, the reflected lights of the lights a1, a2, a3, b1 and b2 are suppressed. A liquid crystal panel 30 including a polarizing member, a driving IC 34, and an FPC (flexible printed circuit board) is disposed above the upper housing 28. As the resin material of the upper housing 28 and the lower housing 29, ABS material or PS is used.
(Vinyl chloride) material or PC (polycarbonate) material is used.

The present invention will be described with reference to FIG. 2, which is the second embodiment. In FIG. 2, a fluorescent tube 50, which is a light source, is disposed in the housing 20 having a window 27 that guides light from the light guide member 40 to the liquid crystal panel 30, and between the side of the fluorescent tube 50 and the housing 20. A reflection sheet 60 for reflecting the light of the fluorescent tube 50 toward the light guide member 40 is disposed in the fluorescent tube 50.
There is also a case where the surface of the housing body 20 for housing is light reflecting color, for example, white or silver. As the container 20, a resin material such as ABS material, PS (vinyl chloride) material, or PC
Although the (polycarbonate) material is molded and used, a metal plate may be molded and used. The housing body 20 has a window surface 11, a window adjoining surfaces 12 and 13, a window surface 15 and a window adjoining surface 16 of the housing body 20 coated with black for antireflection treatment. This antireflection treatment is also performed on the surfaces that are arranged in the front and back of the drawing, which cannot be shown in the drawing, similarly to the surfaces 11, 12, and 13. The surface of the window, the adjacent surface of the window, and the peripheral surface of the window, including surfaces not denoted by reference numerals in FIG. 2, refer to surfaces that cause unnecessary reflection that causes uneven brightness in the vicinity of the window. As a reflection treatment method, black or gray spray coating, offset printing coating, or satin finish is applied.

As the reflection sheet, for example, an aluminum vapor deposition film of polyester or a sheet having a light reflection function by coloring in white is used. The light guide member 4 is provided on the side surface of the fluorescent tube 50 opposite to the housing 20 with respect to the fluorescent tube 50.
0 is allocated. The light guide member 40 may be formed by laminating a large number of transparent plate-shaped bodies made of acrylic resin on each other, or may be formed by a single acrylic plate. A diffusing member 70 is disposed on the light guide member 40. Depending on the specification conditions, a light collecting member 72, which is a prism sheet for collecting the diffused light, is provided above the light diffusing member 70. Diffusing member 7
0 is a milky white or translucent acrylic plate. The polarization member 32 and the driving IC are provided above the light collecting member 72.
A liquid crystal panel 30 including 34 and an FPC 36 is arranged.
Further, in order to support the liquid crystal panel 30 in the housing 20, a front surface supporting member 85 is arranged above the liquid crystal panel 30, and the housing 20 and the front surface supporting member are engaged with each other by a hook to complete a liquid crystal display device. As the front surface support member 85, a metal plate is molded, but an ABS material, a PS (vinyl chloride) material, or a PC (polycarbonate) material, which is a resin material, is molded.

The operation of FIG. 2 will be described. Fluorescent tube 5
Light emitted from 0 enters the light guide member 40. Internal light a1 of this light
Corresponds to the surface 13, but the surface 13 is subjected to antireflection treatment, and the light a2 does not reach the viewer 80. On the other hand, the light a5 is reflected by the reflecting portion 42 at the bottom of the light guide member 40, then passes through the diffusing member 70, the light collecting member 72, and the liquid crystal panel 30, and reaches the viewer 80. The light a3 transmitted through the light guide member 40 reaching the end portion on the side opposite to the fluorescent tube 50 is stored in the housing body 20.
The light a2 hits the antireflection surface 16 of the viewer 8
It does not reach 0. The light a4 hits the antireflection surface 15 of the housing body 20 and the light a4 does not reach the viewer 80. In this way, by actually performing the black antireflection treatment on the container, it is possible to prevent partial brightness increase due to reflection.

[0020]

As described above, according to the present invention, in a liquid crystal display device having a housing, the housing can be partially or wholly subjected to antireflection treatment, thereby preventing a problem that brightness is partially raised due to unnecessary reflection. . Therefore, it is possible to obtain the liquid crystal display device in which the uneven brightness due to reflection is suppressed and the display quality is improved.

The storage bodies are an upper storage body and a lower storage body. The upper storage body is formed of a resin material using a color such as black or gray that prevents reflection of light, and the lower storage body is white that reflects light. Alternatively, by molding with a resin material that uses a reflective color such as milky white or silver, or stainless steel or aluminum, it is possible to reduce the number of reflective sheets and reduce the number of man-hours required for antireflection coating on the upper housing, which is effective in reducing costs. is there.

Although the embodiment has been shown in which the housing body is divided into an upper housing body and a lower housing body, the present invention can perform antireflection treatment on the housing body disposed above the light guide member and the light source. Because of the feature, even if the storage member is composed of three members having a spacer having a window substantially in the display image area, if the light reflected from the spacer causes uneven brightness, the antireflection treatment of the present invention is applied to the spacer. By doing so, it is possible to obtain a liquid crystal display device with good display quality in which uneven brightness is suppressed.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of main members in a liquid crystal display device using an edge light type illumination device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part of a liquid crystal display device using an edge light type illumination device according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view of a main part of a conventional edge light type liquid crystal display device.

[Explanation of symbols]

 11, 12, 13, 15, 16 surface 20 storage body 21, 22, 23, 24, 25, 26 surface 27 window 28 upper storage body 29 lower storage body 30 liquid crystal panel 40 light guide member 41 light emission surface 50 fluorescent tube 60 Reflective sheet 70 Front support member

Claims (5)

[Claims] 1. A liquid crystal display device having a housing, wherein the housing has a window for guiding light emitted from the light guide member to the liquid crystal panel, and at least a surface of the window portion, an adjacent surface and a periphery thereof. A liquid crystal display device comprising the housing, characterized in that a surface thereof is subjected to antireflection treatment. 2. A liquid crystal display device having a housing, wherein the housing comprises an upper housing and a lower housing, and at least the upper housing receives light emitted from the light guide member. A liquid crystal display device comprising the upper frame housing, which has a window leading to the liquid crystal panel, and is configured such that at least a surface of the window portion, an adjacent surface, and a peripheral surface are subjected to antireflection treatment. 3. The liquid crystal display device according to claim 1, wherein the antireflection treatment is black treatment. 4. The liquid crystal display device according to claim 1, wherein the antireflection treatment is gray treatment. 5. The liquid crystal display device according to claim 1, wherein the antireflection is a satin treatment.