JP3093034B2 - Liquid crystal display - Google Patents

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.
More specifically, the present invention relates to a large-sized liquid crystal display device which can efficiently and uniformly illuminate a liquid crystal panel.

[0002]

2. Description of the Related Art In a liquid crystal display device, electrodes are arranged on both sides of a liquid crystal layer, and a light source is arranged on the back side by changing the orientation of liquid crystal molecules in accordance with a voltage applied between the two electrodes for each pixel. Is changed, and characters and figures assembled by the pixels are displayed. Therefore, a driving circuit for controlling the application of a voltage is provided for each pixel, and is arranged around the liquid crystal panel.

Conventional liquid crystal display devices are mainly used for game machines such as timers and display devices of various electronic devices, and OA devices such as word processors and personal computers, all of which are for personal use and relatively small in size.
There is not so much variation in screen brightness. Moreover, it is used personally and viewed near the LCD panel.
Since the brightness of the screen can be adjusted according to personal preference, the influence of the display brightness on the screen is not a problem.

[0004]

The liquid crystal display device consumes less power and can be made a thin display device. It can be used not only for conventional indoor electronic devices and game machines, but also in places where external light is strong such as streets and many others. It is considered to be used for information boards in public facilities where people gather. In this case,
The display panel itself must be large, for example 10
Dozens of cm-sized liquid crystal display panels are arranged vertically and horizontally in a matrix.
In some cases, it is necessary to arrange a large-sized display device in which one to several hundreds are arranged and one side is several meters. Moreover, in spite of strong external light, an unspecified large number of people need to see and be recognized uniformly at the same time. Therefore, it is necessary to clearly display the screen, and a conventional display device of this type uses a display device using an LED, a CRT, or the like.

Further, when the size of the liquid crystal display device is increased, the size of the liquid crystal display panel becomes large, and the proof that the light is illuminated from the back surface is weak at the end of the panel far from the light source. There is a problem that the edge portion is weaker than the center portion and the display on the edge portion becomes unclear. When the display panels are arranged vertically and horizontally, an unclear area is formed around a clear display portion,
Since this is repeated vertically and horizontally, the large screen as a whole has a mottled display screen in which an unclear portion is formed around a clear portion of the display, and there is a problem that it is difficult to see.

Further, each unit liquid crystal display panel is formed by a large number of pixels, and it is necessary to control lighting and non-lighting for each pixel. A driving circuit is formed around each liquid crystal display panel. Printed circuit board is placed. Since the printed circuit board portion is not displayed, if a large area is taken up on the surface of the display panel, the non-display portion becomes large, which hinders continuous display of large characters and the like. On the other hand, if the printed circuit board portion is bent to the back side, the light of the light source arranged at the lower part of the display panel is blocked, and there is a problem that uniform display is also hindered.

An object of the present invention is to solve these problems and to provide a large-sized liquid crystal display device in which an unspecified number of people can be seen at the same time and a uniform and clear display can be obtained.

[0008]

A liquid crystal display device according to the present invention is a large-sized liquid crystal display device in which a driving circuit is formed on substrates disposed on both sides of a liquid crystal display panel, wherein the driving circuit is formed. A substrate is arranged on the back side of the liquid crystal display panel so that the back side is vertically opposed to the panel, the back side of the substrate is formed on a light reflecting surface, and a light source is arranged on the back side of the liquid crystal panel. It is characterized by becoming.

It is preferable that the light reflecting surface formed on the back surface of the substrate has a light reflecting material film attached thereto or a light reflecting plate is attached to the substrate.

If one end of the substrate is rotatably supported, it is convenient to replace the light source.

[0011]

According to the present invention, the substrate on which the drive circuit is formed is arranged in a U-shape from both sides of the display panel to the back side of the display panel in a direction perpendicular to the panel, with the back side facing the panel. Since the opposite back surface of the substrate is formed on the light reflection surface, light from the light source disposed on the back surface side of the display panel is also reflected by the light reflection surface, and the light from the light source disposed on the back side of the display panel is reflected on the back surface of the display panel. Return. Therefore, reflection is repeated on the U-shaped reflecting surface, and the end of the display panel is also illuminated uniformly and brightly.

Further, the substrate on which the drive circuit is formed is formed in a U-shaped cross section on both sides of the display panel, and there is no substrate on the other sides of the display panel. Although it has a tunnel shape, a rod-shaped fluorescent lamp is used as a light source for this type of liquid crystal display device, and a large number of fluorescent lamps are arranged continuously over the fluorescent lamp. In addition, the end portion is also illuminated by the light source similarly to the center portion, and uniform illuminance is obtained.

Further, since the substrate is formed in a direction perpendicular to the display panel, even if the display panel is continuously arranged on one side of the substrate, only a gap of about the thickness of the substrate is formed. And a large display screen is formed without deteriorating the display state.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view conceptually showing a unit liquid crystal display panel of a liquid crystal display device according to an embodiment of the present invention. In an actual large-sized liquid crystal display device, a large number of unit liquid crystal display panels are arranged vertically and horizontally (a part of the liquid crystal display panel is shown by a two-dot chain line in FIG. 1) to form a large display screen. This one unit liquid crystal display panel has 24 × 24 pixels or 36 × pixels depending on the application.
The unit display panel is formed into 36 pieces or the like, is formed in a size of about 10 cm square, and is configured by arranging several to several hundred unit display panels according to the application.

In FIG. 1, reference numeral 1 denotes a liquid crystal display panel, which is filled with a liquid crystal between transparent substrates 1a and 1b such as glass plates to form a liquid crystal layer 1c, and each pixel is formed by an electrode film formed on both transparent substrates. The voltage is applied and displayed. Whether a voltage is applied to the pixel or not is determined based on an external signal, and a drive circuit formed on the printed circuit board 3 sends an ON / OFF signal to each pixel. Signals from the drive circuit are connected via a TAB2 in which a thin metal wire is formed on the insulating film and is automatically bonded to each electrode pad.
This drive circuit drives, for example, about 576 pixels formed in one unit of display panel, and can be formed on both sides of the display panel to drive all the pixels of the unit liquid crystal display panel.

In the present invention, as shown in FIG. 1, the printed circuit board 3 on which the drive circuit is formed is disposed on both sides in the direction of the back surface of the display panel 1 and substantially perpendicular to the display panel by bending the TAB. . Electronic components such as ICs and diodes are arranged in a hybrid manner on the front side facing the outside of the printed board 3, wiring is performed on the back side of the printed board 3, and a drive circuit is formed. The back surface of the printed circuit board 3 is coated with a white silk 4 which is also used to stop the flow of solder so as to cover the wiring leads, and serves as a light reflecting surface. Therefore, in the light emitted from the light source 5, the light traveling in the horizontal direction is reflected by the white silk 4, the reflected light is also reflected in various directions depending on the direction of the emitted light, and the light is also applied to the end of the liquid crystal display panel 1. As a result, uniform brightness of the display surface can be obtained.

The above-mentioned white silk 4 is formed by a printing method or the like after a drive circuit is formed on the printed circuit board 3, so that the surface of the white silk 4 is formed in a plane, and efficient reflected light is formed. In order to make the back surface of the printed circuit board 3 a reflective surface, the example of white silk printing has been described.
The present invention is not limited to this example, and a paint having electrical insulation properties may be applied by a printing method or the like.

Further, a glass plate, a plastic plate or the like can be attached to the back surface of the printed circuit board 3 so as to be formed.
A metal material with excellent reflection characteristics such as aluminum is further adhered to these surfaces, or a resin plate or ceramic plate is attached to the back surface of the printed circuit board, and a reflective film such as a metal film is formed on the surface. You may.

Further, in the above-described embodiment, the example in which the drive circuit is formed on the printed circuit board 3 has been described. However, the present invention is not limited to the printed circuit board, and a thin film transistor or the like may be formed on an insulating film. In this case, not only the electrically insulating paint, but also a metal material or a reflective paint directly applied to the back surface of the substrate,
It may be formed by vapor deposition or the like.

Further, the electric wiring between each electrode of the liquid crystal display panel 1 and the printed circuit board has been described by using an example in which the TAB 2 is used, in which a thin metal wire is attached to a flexible film and can be automatically bonded. LCD panel 1
What is necessary is just to be able to bend in a direction almost perpendicular to
A flexible printed circuit made of polyimide or the like may be used.

According to the structure of the present invention, the printed circuit board is formed in a U-shape, and is disposed so as to straddle the light source. Therefore, as shown in FIG. By rotating each unit panel one after another in the direction of arrow B, even a long light source such as a fluorescent lamp is completely exposed, and replacement is easy. That is, when the reflector is formed upright from the light source side, the liquid crystal display panel must be completely removed to replace the fluorescent lamp as the light source. However, according to the present invention, the light source can be easily replaced simply by rotating and tilting. Can be.

[0022]

According to the present invention, the substrate on which the drive circuit of the liquid crystal display panel is formed is formed so as to be substantially perpendicular to the back side of the display panel, and the back surface facing the inside of the substrate is a reflective surface. Therefore, light from the light source is reflected on the back surface of the substrate and is efficiently condensed on the liquid crystal display panel. In addition, since a new light reflecting plate or the like is not separately formed but conventional components are used as they are, it can be configured in a small space. As a result, the brightness of the liquid crystal display panel becomes uniform at both the center and the periphery.By arranging a large number of unit liquid crystal display panels in a matrix, a large-sized liquid crystal display device that excels in bright and clear display characteristics can be obtained. Thus, it can be used as a display device for unspecified people on the street or in public facilities.

Further, since the substrate on which the drive circuit is formed is formed in a direction perpendicular to the display panel, a portion having no liquid crystal layer hardly appears on the surface when arranging the unit liquid crystal display panels vertically and horizontally. A large liquid crystal display device having excellent display characteristics can be obtained.

Further, according to the present invention, the light source is exposed by rotating each unit display panel around the end of the substrate on which the drive circuit is formed as a fulcrum, and maintenance such as replacement of the light source is easy. .

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a unit liquid crystal display panel portion of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of FIG. 1, illustrating an example of replacing a light source by rotating a liquid crystal display panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display panel 3 Printed circuit board 4 White silk 5 Light source

Claims (4)

(57) [Claims] 1. A large-sized liquid crystal display device in which a driving circuit is formed on substrates disposed on both sides of a liquid crystal display panel, wherein the substrate on which the driving circuit is formed is provided on a back side of the liquid crystal display panel. A liquid crystal display device comprising: a rear surface of the liquid crystal panel disposed so as to face a panel in a vertical direction; a rear surface of the substrate formed on a light reflecting surface; and a light source disposed on a rear surface of the liquid crystal panel. 2. The liquid crystal display device according to claim 1, wherein the light reflecting surface on the back surface of the substrate is formed by attaching a light reflecting material to the back surface of the substrate. 3. The liquid crystal display device according to claim 1, wherein the reflection surface of the back surface of the substrate is formed by attaching a light reflection plate to the back surface of the substrate. 4. The liquid crystal display device according to claim 1, wherein one end of the substrate is rotatably supported.