JPH0829781A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To enlarge buffering force against outside impact and to prevent the entering of fine dust into gaps by adhering and holding the rear surface of a liquid crystal display panel and an illuminator via a transparent elastic body covering at least an effective display region surface. CONSTITUTION:The illuminator 2 for introducing illuminating light to the effective display region surface of the liquid crystal display panel 1 is arranged at the rear side of the liquid crystal display panel 1. A planar elastic body 3 is arranged over whole surface of the effective display region of the liquid crystal display panel 1 and is adhered and bonded with the illuminator 2. The elastic body 3 is composed of a planar sheet which is made of, for example, transparent silicone rubber by molding and has high transmitivity and about 20 rubber hardness. In the combination bonding between the liquid crystal display panel 1 and the illuminator 2, whole surface corresponding to the effective display region in the rear surface of the liquid crystal display panel 1 and the light emitting surface of the illuminator 2 are adhered while holding the elastic body 3 therebetween and the liquid crystal display panel 1 and the illuminator 2 are press-contacted and held by pressing from both outsides.

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, and more particularly to a combined structure of a liquid crystal display panel and a lighting device.

[0002]

2. Description of the Related Art Liquid crystal display devices are widely used as character displays for numbers, characters and graphic symbols because of their thinness, light weight and low power consumption. The liquid crystal display itself discriminates by utilizing transmitted light or reflected light by controlling the shape of liquid crystal molecules depending on whether or not a voltage is applied.

However, since the liquid crystal display device does not emit light by its operating principle, the display cannot be identified in a dark place. Similarly, even in a bright place, the display is subject to certain restrictions due to the problem of contrast. Therefore, in order to solve these problems, a liquid crystal display device is used in which visibility is improved by combining a liquid crystal display panel and a lighting device.

For example, there is used a liquid crystal display device in which a liquid crystal display panel and an illuminating device are combined and light from the illuminating device is transmitted through the liquid crystal display panel to improve visibility. In this case, there are used a back lighting method in which a light source of the lighting device is arranged on the back surface of the display surface of the liquid crystal display panel and a side lighting method in which the light source is arranged on the side surface of the liquid crystal display panel and guided from the side surface.

A thin fluorescent tube or the like is used as a light source in the side illumination system, but a light guide plate is provided to compensate for sufficient illuminance and uniform illuminance distribution over the entire effective display area of the liquid crystal display panel. And a light diffusion plate is required. In this method, it is important to design the light diffusion plate to compensate for the uniform illuminance distribution.

On the other hand, the light source of the back lighting system requires a light diffusing plate for compensating a uniform illuminance distribution when, for example, a thin fluorescent tube is used. However, when a surface light emitting plate using electroluminescence (EL) is used as a light source, the light diffusing plate may be omitted in some cases.

FIG. 2 shows a schematic structure of a liquid crystal display device including such a liquid crystal display panel and a lighting device. That is, the illumination device 2 that introduces illumination light to the effective display area surface of the liquid crystal display panel 1 is arranged on the back side of the liquid crystal display panel 1.

The peripheral portion of the liquid crystal display panel 1 outside the effective display area is configured to be connected to the illuminating device 2 by sandwiching a band-shaped elastic body 4 made of silicone rubber or the like. The purpose of sandwiching the liquid crystal display panel 1 and the illuminating device 2 at their peripheral portions with the band-shaped elastic body 4 in this way is as follows.

That is, firstly, the liquid crystal display panel and the peripheral portion of the illuminator are firmly held in pressure contact with each other. Secondly, the shock from the outside is buffered by the elastic body. Third
In addition, this is to absorb the variation in the dimensional tolerance in the thickness direction of each component forming the liquid crystal display device. Fourthly, it is to absorb the variation in the dimensional variation in the thickness direction of each component constituting the liquid crystal display device due to the thermal change. Fifthly, when the liquid crystal display panel and the lighting device are brought into close contact with each other, a fine air layer may be generated, and interference fringes may be visually recognized on the display surface. This is to maintain the function of the spacer that maintains the gap.

[0010]

However, as shown in FIG. 2, a band-shaped elastic body made of silicone rubber or the like is sandwiched at the peripheral portion outside the effective display area of the liquid crystal display panel so as to be connected to the lighting device. Also has the following problems.

That is, since the contact of the elastic body is small only in the peripheral portion of the liquid crystal display panel, the buffering force against external impact is not so large and is relatively weak. Further, when the gap between the liquid crystal display panel and the light emitting surface of the lighting device is small, it is difficult to maintain a predetermined gap, and interference fringes may be visually recognized on the display surface. Furthermore, fine dust is easily mixed in the gap between the liquid crystal display panel and the light emitting surface of the lighting device, which easily causes image defects on the display surface.

The present invention has been made in view of the above problems, and in a liquid crystal display device including a liquid crystal display panel and an illuminating device for introducing light into an effective display area of the liquid crystal display panel, an external impact is applied. Has a large buffering force against
An object of the present invention is to provide a liquid crystal display device that prevents the mixing of fine dust into the gap between the liquid crystal display panel and the light emitting surface of the lighting device, and that the gap is reliably maintained and interference fringes are not visible. To do.

[0013]

The present invention provides a liquid crystal display device comprising a liquid crystal display panel including a drive circuit and an illuminating device for introducing light into an effective display area of the liquid crystal display panel. The above object is achieved by providing a liquid crystal display device in which the back surface and the lighting device are closely sandwiched by a transparent elastic body that covers at least the effective display area surface of the liquid crystal display panel.

[0014]

In the liquid crystal display device of the present invention, the back surface of the liquid crystal display panel and the light emitting surface of the illuminating device are closely sandwiched by a transparent elastic body having a high light transmittance which covers at least the effective display area surface of the liquid crystal display panel. ing.

Therefore, the contact area of the elastic body has at least the area of the effective display area of the liquid crystal display panel, and since the contact area is large, the cushioning force against external impact is significantly improved and becomes large.

Further, due to the existence of the transparent elastic body, there is no possibility that fine dust is mixed between the back surface of the liquid crystal display panel and the light emitting surface of the lighting device. Further, since the gap between the back surface of the liquid crystal display panel and the light emitting surface of the lighting device can be stably and reliably maintained, it is possible to selectively prevent the generation of interference fringes visually recognized on the display surface of the liquid crystal display panel. it can.

[0017]

EXAMPLES Examples of the present invention will be described in detail below. FIG. 1 shows a schematic configuration of a liquid crystal display device according to an embodiment of the present invention, which includes a liquid crystal display panel and a lighting device. Since the liquid crystal display panel and the illuminating device itself applied to this embodiment are the same as the conventional ones, detailed description thereof will be omitted.

In FIG. 1, an illumination device 2 for introducing illumination light to the effective display area surface of the liquid crystal display panel 1 is disposed on the back side of the liquid crystal display panel 1. The planar elastic body 3 is arranged over the entire effective display area of the liquid crystal display panel 1 so as to be sandwiched and coupled to the illumination device 2. The elastic body 3 is composed of a flat sheet having a high light transmittance, for example, a rubber hardness of about 20 molded from transparent silicone rubber.

The combination of the liquid crystal display panel 1 and the illuminating device 2 is such that the entire surface corresponding to the effective display area on the back surface of the liquid crystal display panel 1 and the light emitting surface of the illuminating device are made of the elastic body 3.
The liquid crystal display panel and the illuminating device are held by sandwiching and closely adhering, and applying pressure from both sides from outside to press and sandwich.

[0020]

As described above, according to the present invention, the back surface of the liquid crystal display panel and the illuminating device are closely sandwiched by the transparent elastic body having a high light transmittance covering at least the effective display area surface of the liquid crystal display panel. By doing so, the buffering force against external shock is large, and it is possible to prevent the mixing of fine dust into the gap between the liquid crystal display panel and the light emitting surface of the lighting device, and to maintain the gap reliably, so that interference fringes are visible. The liquid crystal display device can be used.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a combined state of a liquid crystal display panel and a lighting device as an embodiment of a liquid crystal display device of the present invention.

FIG. 2 is a schematic configuration diagram showing a combined state of a conventional liquid crystal display panel and a lighting device.

[Explanation of symbols]

 1 ... Liquid crystal display panel, 2 ... Illumination device, 3 ... Elastic body.

Claims (1)

[Claims] 1. A liquid crystal display device comprising a liquid crystal display panel including a drive circuit and an illuminating device for introducing light into an effective display area of the liquid crystal display panel, wherein at least the back surface of the liquid crystal display panel and the illuminating device. A liquid crystal display device, wherein the liquid crystal display panel is closely sandwiched by a transparent elastic body that covers an effective display area surface of the liquid crystal display panel.