JPH10171378A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the image display device which can sufficiently secure a gap for air ventilation and obtain high cooling effect. SOLUTION: The device is equipped with a display panel which has a driving substrate 33 connected by a flexible wiring board 41 and a surface light source unit which has specific openings and is cooled by ventilation; and the driving substrate 33 is fitted behind the said surface light source unit and the flexible wiring board 41 is positioned above the openings, thus constituting the image display device. The flexible wiring board 41 is so constituted that a halfway part connecting the display panel and driving substrate 33 is narrower than the connection parts of them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device provided with a surface light source unit for backlighting having a cooling mechanism, and more particularly to an improvement in cooling efficiency.

[0002]

2. Description of the Related Art In a transmissive display panel such as a liquid crystal display panel, it is common to arrange a surface light source unit on the back side to perform backlight illumination.

In this case, the light source in the surface light source unit serves as a heat source and generates a large amount of heat. In particular, it is necessary to suppress temperature rise of a panel using liquid crystal as much as possible. Also,
In flat display devices, since the entire product including the surface light source unit is required to be thinner, the surface light source unit, which is a heat source, and the flat display device must be closely arranged in a thin cabinet with a small capacity. Become. Therefore, how to efficiently cool the heat is an important issue.

When the temperature of the display panel rises due to the heat generated by the light source, for example, the electro-optical characteristics of the liquid crystal change, and the image quality is greatly impaired. Further, when a fluorescent tube is used as the light source, the luminous efficiency is reduced due to an increase in the ambient temperature, and the luminance is reduced.

[0005] In order to solve this problem, it is conceivable to indirectly cool the light source by blowing cooling air to the rear surface of the reflector. In this type of surface light source unit, it is necessary to arrange the light source in a closed space in order to minimize the influence of dust and dirt, and when such a structure is employed, the light source cannot be directly cooled. Because.

[0006]

When the above-described surface light source unit is installed, it is preferable to install the surface light source unit as close as possible to the rear surface of the display panel. Therefore, the surface light source unit is arranged in contact with the rear surface of the display panel. A structure is adopted in which a driving substrate having a driving circuit for driving a display panel is provided behind the surface light source unit.

[0007] In this case, it is necessary to electrically connect the display panel and the drive board, and the connection by the flexible wiring board is widely performed.

[0008] However, when the display panel and the drive board are connected by the flexible wiring board, the flexible wiring board is wired over the surface light source unit, so that the cooling air blower is closed. Become.

In a display panel, since the drive electrodes are formed over substantially the entire width of the panel, the flexible wiring board also has a width corresponding to this.

[0010] Therefore, most of the air outlet is closed, and the cooling efficiency is greatly impaired.

Usually, the flexible wiring board is divided into a plurality of pieces, and a gap between the flexible wiring boards is several mm, which is a clearance width for pressure bonding to the display panel.
It is not possible to secure a sufficient space for ventilation.

Accordingly, the present invention has been proposed in view of such a conventional situation, and an image display capable of sufficiently securing a gap for ventilation and obtaining a high cooling effect. It is intended to provide a device.

[0013]

In order to achieve the above-mentioned object, the present invention provides a display panel in which a driving board is connected by a flexible wiring board, and a surface light source unit having a predetermined opening and cooled by blowing air. Wherein the driving substrate is attached to the rear of the surface light source unit, and the flexible wiring substrate is located on the opening. In the image display device, the flexible wiring substrate has a connection portion between the display panel and the driving substrate. It is characterized in that the width of the halfway connecting these is smaller than the width.

By making the width of the middle part of the flexible wiring board narrower than the connection part to the display panel or the drive board,
For example, the gap between the adjacent flexible wiring boards can be increased, and the air is smoothly ventilated to ensure the cooling efficiency.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

This embodiment is an example applied to a so-called plasma addressed display device. As shown in FIGS. 1 and 2, an electro-optical display cell 1 and a plasma cell 2
And a so-called flat panel structure in which a dielectric sheet 3 interposed therebetween is laminated.

The dielectric sheet 3 is made of thin glass or the like and functions as a capacitor by itself. Therefore, in order to sufficiently secure the electrical coupling between the electro-optical display cell 1 and the plasma cell 2 and to suppress the two-dimensional spread of electric charges, it is preferable that the dielectric sheet 3 is as thin as possible. Specifically, for example, a thin glass plate having a thickness of about 50 μm is used.

The electro-optical display cell 1 is formed by bonding a glass substrate (upper substrate) 4 on the dielectric sheet 3 with a predetermined gap maintained by a spacer 6.

The gap between the dielectric sheet 3 and the upper substrate 4 is filled with a liquid crystal material as an electro-optic material, and a liquid crystal layer 7 is formed. In addition, as the electro-optic material, a material other than the liquid crystal can be used.

Here, the size of the gap between the upper substrate 4 and the dielectric sheet 3 is, for example, 4 to 10 μm, and is kept substantially uniform over the entire display surface.

On the surface of the upper substrate 4 facing the dielectric sheet 3, a plurality of data electrodes 5 made of a transparent conductive material and extending in the row direction, for example, are arranged in parallel in the column direction while maintaining a predetermined interval. Are arranged.

On the other hand, the plasma cell 2 is composed of the dielectric sheet 3 and a glass substrate (lower substrate) 8 disposed below the dielectric sheet 3.

On a surface of the lower substrate 8 facing the dielectric sheet 3, a plurality of anode electrodes 9A and cathode electrodes 9K extending in a direction orthogonal to the data electrodes 5, that is, in a column direction.
Are alternately arranged in parallel while maintaining a predetermined interval, and constitute a discharge electrode group as a drive electrode.

The center of the upper surface of each of the anode electrode 9A and the cathode electrode 9K is extended along the electrodes.
A partition 10 having a predetermined width is formed. And each partition 1
The top of 0 is in contact with the lower surface of the dielectric sheet 3, and the gap between the lower substrate 8 and the dielectric sheet 3 is kept substantially constant.

Further, the dielectric sheet 3 has a frit seal 11 using a low melting point glass or the like at the outer peripheral edge.
Accordingly, the plasma cell 2 is hermetically bonded to the lower substrate 8, and the plasma cell 2 is configured as a closed space.
An ionizable gas such as helium, neon, argon, or a mixture thereof is sealed in the closed space.

In the above-described plasma addressed display panel, each partition 10 is provided between the lower substrate 8 and the dielectric sheet 3.
Are formed in parallel in the row direction. This discharge channel 12 is orthogonal to the data electrode 5.

Therefore, each data electrode 5 is a unit of column drive, and each discharge channel 12 is a unit of row drive. As shown in FIG.

In the plasma addressed display panel having the above structure, when a driving voltage is applied between the anode electrode 9A and the cathode electrode 9K corresponding to a predetermined discharge channel 12, the gas sealed in the discharge channel 12 is discharged. When ionized, plasma discharge occurs and is maintained at the anode potential.

When a data voltage is applied to the data electrode 5 in this state, the data voltage is applied to the liquid crystal layer 7 corresponding to the plurality of pixels 13 arranged in the column direction corresponding to the discharge channel 12 where the plasma discharge has occurred. Written.

When the plasma discharge ends, the discharge channel 12 becomes a floating potential, and the data voltage written in the liquid crystal layer 7 corresponding to each pixel 13 is held until the next writing period (for example, after one field or one frame). Is done. In this case, the discharge channel 12 functions as a sampling switch, and the liquid crystal layer 7 of each pixel 13 functions as a sampling capacitor.

The liquid crystal operates by the data voltage written in the liquid crystal layer 7, and display is performed in pixel units. Therefore, the discharge channel 12 for generating the plasma discharge
Are sequentially scanned, and a data voltage is applied to each data electrode 5 in synchronization with the scanning, whereby the liquid crystal layer 7 is driven in the same manner as in the active matrix addressing method, and a two-dimensional image can be displayed.

In a normal liquid crystal panel, it is necessary to suppress the temperature rise as much as possible.

Therefore, a surface light source unit is arranged on the back of the display panel.

As shown in FIG. 4, the surface light source unit 21 has fluorescent tubes 23 arranged in a housing 22 and a reflector 24 disposed on the back side of the fluorescent tubes 23.

The light irradiating surface of the housing 22 is provided with a diffusion plate 25.
Are arranged, and the diffusion plate 25, the reflection plate 24, and the housing 22
A closed space is formed by the side surface portion 22a of this embodiment, and the fluorescent tube 23 is housed in the closed space. The reason why the fluorescent tube 23 is housed in the closed space is to minimize the influence of dust and dirt.
Dust adheres to the fluorescent tube 23 and the diffusion plate 25 and is visually recognized by an observer through the display panel, and image quality is significantly impaired.

The diffusing plate 25 is for diffusing light from the fluorescent tube 23 to make it uniform, and a plate in which light diffusing fine particles are dispersed in a transparent resin such as an acrylic resin or a frosted glass is used. Can be

On the other hand, a space is also formed on the back side of the reflection plate 24, and this space is an open space by providing an opening 22 b in the side surface portion 22 a of the housing 22.

By blowing air from a cooling fan or the like from the opening 22b, cooling air flows as shown by the arrow in the figure, and the surface light source unit 21 is cooled.

A circuit board 6 including an inverter circuit and the like is mounted in the space on the back side of the reflection plate 24, and is electrically connected to the fluorescent tube 23 to drive it. I have.

The above-described display panel and surface light source unit 21
Are supported by various frames and the like, and are assembled as an image display device.

FIG. 5 shows this assembled state.

The image display device of the plasma address type is
As shown in FIG. 5, the above-described display panel is supported by a frame 31 and attached to a front frame 32. Further, a driving circuit for driving the display panel and the like are provided on the back side of the display panel. A chassis 34 on which a driving board 33 is provided, a shield cover 35 covering the chassis 34, and a rear cover 36 are sequentially attached. Further, speaker units 37 are mounted on both sides of the front frame 32.

The chassis 34 has an accommodation space for accommodating the surface light source unit 21, and the unitized surface light source unit 21 is accommodated in the accommodation space by a slide method.

The chassis 34 also has an opening 34a corresponding to the opening 22b of the surface light source unit 21, and a cooling fan (not shown) allows cooling air to flow through the opening 34a and the opening 22b. Unit 21
It is forcibly sent into the inside and is efficiently cooled by air.

When such an assembly structure is adopted,
As shown in FIG. 6, it is necessary to connect the display panel P and the drive board 33 by the flexible wiring board 41. In this example, four flexible wiring boards 41 connect electrodes over the entire width of the display panel P.

Here, the flexible wiring board 41
The surface light source unit 21 is connected to a drive board 33 attached to a chassis 34 so as to straddle the opening 22b of the surface light source unit 21 and the opening 34a provided in the chassis 34.

Therefore, in this example, the width of the intermediate portion 41a of each flexible wiring board 41 is made narrower than the other portions,
The gap between them is enlarged.

In FIG. 6, each flexible wiring board 4
The hatched area 1 indicates the display panel P or the driving substrate 33.
Connecting portions 42b and 42c.

Here, the portion of the flexible wiring board 41 on the display panel P side, that is, the width of the connection portion 42b is set to W ₁ ,
The spacing between each of the flexible wiring board 41 and D _1. Similarly, the width of the portion on the drive substrate 33 side, that is, the width of the connection portion 42c is W ₂ , and the interval between the flexible wiring substrates 41 is D ₂ . The opening 22b facing the portion of the surface light source unit 21, i.e., the interval in the middle portion 41a of the flexible wiring board 41 and D _3.

[0050] Normally, the connection portion 41b, to increase the reliability of positional deviation in 41c, it is preferable to maximize the electrode pitch, and maximize the width W _1, W _2, the distance D _1, D ₂ It is preferable to make it as small as possible.

In this case, the flexible wiring board 41 has a straight structure, and the electrode wiring portion (intermediate portion 41) is formed.
When a) is also the same _{width, D 3 ≒ D 1 ≒ D} 2 , and the distance between the flexible wiring board 41a is limited by the distance D _1, D _2.

In this embodiment, as shown in FIG. 7, the pitch of the electrode e of the intermediate portion 41a is smaller than the pitch of the electrode e of the connection portions 41b and 41c at both ends of the flexible wiring board 41. Is the feature.

The flexible wiring board 4 having such a setting
In the case of 1, the relationship D ₃ > D ₁ ≒ D ₂ holds, and the distance D ₃ between the flexible wiring boards 41a can be increased.

In this embodiment, the pitch of the electrodes e of the connecting portions 41b and 41c at both ends of the flexible wiring board 41 is set to 0.4 m.
m, and the pitch of the electrode e in the intermediate portion 41a was 0.2 mm.

As a result, the ventilation can be smoothly performed through the gap between the flexible wiring boards 41a, and a sufficient cooling effect can be obtained.

The specific embodiment to which the present invention is applied has been described above. However, it is needless to say that the present invention is not limited to this example, and various modifications are possible.

For example, although the description has been made by taking the plasma address display device as an example, the present invention can be applied to all image display devices such as a normal liquid crystal display device.

[0058]

As is apparent from the above description, according to the present invention, ventilation for cooling can be performed smoothly, and cooling efficiency can be greatly improved.

Therefore, it is possible to provide an image display device with high image quality.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a configuration example of a plasma addressed display panel with a part cut away.

FIG. 2 is a schematic sectional view showing a configuration example of a plasma addressed display panel.

FIG. 3 is a schematic diagram showing an arrangement of data electrodes, discharge electrodes, and discharge channels.

FIG. 4 is a schematic sectional view illustrating a configuration example of a surface light source unit.

FIG. 5 is an exploded perspective view showing a mounting structure of a display panel and a surface light source unit.

FIG. 6 is a schematic perspective view showing a connection state between a display panel and a driving substrate.

FIG. 7 is a plan view schematically showing a wiring example in a flexible wiring board.

[Description of Signs] 21-surface light source unit, 33 drive board, 41 flexible wiring board, P display panel

Claims (2)

[Claims] 1. A drive panel comprising: a display panel connected by a flexible wiring substrate; and a surface light source unit having a predetermined opening and cooled by blowing air, wherein the drive substrate is mounted behind the surface light source unit. In the image display device in which the flexible wiring board is located above the opening, the width of the flexible wiring board is smaller in a halfway portion connecting the display panel and the driving board than in a width of a connection portion thereof. An image display device characterized by the above-mentioned. 2. The image display device according to claim 1, wherein a plurality of flexible wiring boards are connected to the display panel in parallel.