JPH0545630A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain the thin, easy-to-handle liquid crystal display device with lighting of good display quality. CONSTITUTION:A liquid crystal panel 1 constituted by arranging driving elements closely on two adjacent sides and a liquid crystal panel 10 which has less display area are arranged, a photoconductive plate is arranged on the rear surfaces of both the liquid crystal panels, and a bias means is laminated on the driving element on the side of the liquid crystal panel where a light source is not arranged; and electric power and a driving signal are received through the driving substrate of a lighting means 4. The light source is isolated nearly at a distance corresponding to the arrangement of the driving element, the heat of the light source is hardly propagated to the liquid crystal panels and this arrangement does not result in an unnecessary space. Constituent components are decentralized at the periphery of the liquid crystal panels, so the display surface is not made wide and the thickness is thin. Even when plural liquid crystal panels are used, those are arranged on one photoconductive plate, so an irregularity of display hardly appears.

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 having a lighting means.

[0002]

2. Description of the Related Art Conventionally, in a liquid crystal display device, when a thin device is used, a light guide plate is arranged on the back surface of a liquid crystal panel as shown in JP-A-3-50591, and the edge of the light guide plate is arranged. A so-called surface-emission type illumination means in which a light source is arranged in is used, and this light source is a substantially linear light source, and is covered with a reflection plate or the like in order to efficiently guide light to the light guide plate, and is framed together with the drive element. It was stored in the body.

On the other hand, liquid crystal panels having different specifications are sometimes combined to enrich the display contents. In such a case, as shown in Japanese Patent Laid-Open No. 60-24722, an illuminating means is arranged for each liquid crystal panel. , This was unitized and the liquid crystal panels were aligned.

[0004]

However, the light source of the illuminating means raises the temperature, and when the temperature is transmitted to the liquid crystal panel, the display density and contrast are changed to deteriorate the display quality. In order to avoid this, it was considered to cover the light source with a heat insulating material or to provide a sufficient space between the light source and the liquid crystal panel, but since many heat insulating materials absorb light, the amount of illumination light decreases and If a space is provided between the LCD panel and the liquid crystal panel, the frame that houses them will become larger or thicker, and due to the arrangement of components such as the drive circuit, the liquid crystal display in a case with a large effective display surface. Since the terminals such as the drive circuit and the power source of the illumination are liable to be dislocated because they are arranged closer to the corners of the device, the device using the liquid crystal display device is undesirably limited in display arrangement, shape, mounting conditions and the like.

Even if liquid crystal panels of different specifications are used, it is easier to observe if the display conditions are constant and the information is easier to read. However, if each display panel is unitized, the panel surface (display surface) becomes flat. The combination unit is not preferable unless liquid crystal panels of the same size having a large area are used, because the brightness does not exist or the brightness of the display easily varies depending on the display area.

[0006]

The present invention has been made in order to obtain a thin and easy-to-handle liquid crystal display device, in which at least two adjacent sides of the liquid crystal panel are provided with driving elements close to the liquid crystal panel, and one side thereof is provided. A light source is arranged on the side opposite to the liquid crystal panel of the driving element, and more preferably, a liquid crystal panel in which the driving elements are closely arranged on two adjacent sides and a liquid crystal panel having a narrower display area are arranged side by side. A light guide plate is arranged on the back surface of the liquid crystal panel of the liquid crystal panel, a bias means is laminated on a drive element of the liquid crystal panel in which a light source is not arranged, and a drive board for the illumination means is provided in the vicinity of the liquid crystal panel having a small display area. The power supply and the drive signal are received via the drive board of the illumination means.

[0007]

As a result, the position of the light source is separated by the area in which the driving element is arranged, so that the heat of the light source is hard to be transmitted to the liquid crystal panel, and even if the light source is separated, the driving element is located between them, so that a wasteful space is saved. It has not been established. Further, since the driving boards for the bias means and the illuminating means are arranged on the sides of the liquid crystal panel around which the light source is not provided, the effective display surface is substantially centered and the constituent parts are arranged in the entire display device. Therefore, the thickness can be reduced without making the display surface wide. Furthermore, even when a plurality of liquid crystal panels are used, since they are arranged on one light guide plate, uneven display is unlikely to occur. Further, since the signal lines and the like are collected in one place, it is easy to handle even when the liquid crystal display device is rotatably supported.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1, 2 and 3 are a plan view of a liquid crystal display device according to an embodiment of the present invention, and a sectional view taken along line AA and a sectional view taken along line BB. In these figures, 1 is a field effect type liquid crystal panel, for example, 1
It is a super twist nematic type for dot matrix display having a display surface of 70 × 87 mm.
Drive elements 2 and 3 are arranged adjacent to the liquid crystal panel 1 on two adjacent sides of the liquid crystal panel 1, and are different from semiconductor elements supported by a flexible substrate, called tape automated bonding (so-called TAB). The driving element 2 is a common driver for scanning, and the driving element 3 is a data driver for handling dot information. These drive elements are connected to the wiring boards 21, 3
They are interconnected by 1.

Reference numeral 4 is an illuminating means having a light source 41 and a light guide plate 42. The light source 41 is a linear light source such as a cold cathode ray tube.
The drive element 3 on one side in the longitudinal direction of the liquid crystal panel 1 is arranged on the opposite side of the liquid crystal panel 1, and the periphery thereof is covered in a non-contact manner with a reflection sheet 43 made of aluminum foil or the like. On the other hand, the light guide plate 42 is arranged on the back surface of the liquid crystal panel 1, and a reflection film is attached to the bottom surface and a light diffusion sheet is attached to the front surface as necessary, and the back surface of the liquid crystal panel 1 is illuminated. The light guide plate 42 has at least an illuminated surface that is wider than the effective display surface of the liquid crystal panel 1, and the liquid crystal panel 1 may be placed directly on this, but dust or the like will enter between the light guide plate 42 and the liquid crystal panel 1. Since it is illuminated and emerges in the display, it is preferable to keep a constant interval between them by a frame or the like made of an elastic body that serves as a spacer.

When liquid crystal panels having different configurations and having such a structure are used, for example, when the above-mentioned dot matrix display and level display are formed by different liquid crystal panels, the first liquid crystal panel 1 for dot matrix display, A second liquid crystal panel 10 having a display area smaller than that of the first liquid crystal panel for level display is arranged side by side, and a light guide plate having a large area is prepared as the light guide plate of the illumination means 4. The light guide plate 42 is arranged on the back surfaces of the panels 1 and 10. When the first and second liquid crystal panels 1 and 10 are illuminated by the one light guide plate as described above, the light is illuminated by the light that is uniformized by the light guide plate, so that there is no unevenness in the amount of light and the light guide plate is Since the surface of 42 serves as a reference for the flatness of the liquid crystal panel, the display conditions are uniform over a plurality of panels, and the display quality can be kept high.

Next, peripheral components of such a liquid crystal panel will be described.

When the liquid crystal panel is driven by the voltage averaging method, six kinds of bias voltages are required, and if the bias voltages are wired to the driving elements 2 and 3, the power supply line cannot be made too thin, and the wiring width becomes wide. In the example above,
The light source is located on the data driver side, but the lighting means is not located on the common driver side. In consideration of this, the bias means 5 is laminated on the drive element 2 of the first liquid crystal panel 1 in which the light source 41 is not arranged. The bias means is usually composed of a resistance division circuit, a voltage switching transistor, a bias voltage stabilizing amplifier, a surge absorbing capacitor, a bias voltage wiring, and a printed wiring board having these, and is connected to the TAB as a connection substrate of the driving element 2. It can be laminated directly or in the same area and shape as the connection board 21 of the TAB. As for the substrate of such bias means 5, one of the short sides may be connected to the connection board 21 and the other side may be connected to the connection board 31 by a wiring means such as a lead wire, a ribbon wire or a heat seal. As a result, the wiring to each driving element 2 and 3 is relatively short, the surface area of the display device does not increase due to the bias wiring, and the thickness is thinner than the laminated thickness of the liquid crystal panel and the illumination means in the display section. be able to. Further, in a simple display such as a level display, since it can be directly driven by the signal received from the host device, such bias means is not necessary, and therefore the drive element 2 and the bias means 5 are on the opposite side of the liquid crystal panel 1 from the liquid crystal panel 10. It should be installed near the.

On the other hand, the light source 41 of the illumination means 4 requires a lighting control circuit such as an inverter circuit. In the embodiment of the present invention, such a lighting control circuit is mounted on the substrate and
In the vicinity of the liquid crystal panel 10 of FIG. Since the driving substrate 6 of the illuminating means has a width substantially the same as that of the driving element 2 and can be configured to have a thickness substantially the same as the laminated thickness of the liquid crystal panel 1 and the illuminating means 4, the liquid crystal panels 1 and 10 have substantially the same size on both sides. You have placed the components.

Further, the drive power supply of the liquid crystal panel 1, the power supply and drive signals of the drive elements 2 and 3, and the wiring of the liquid crystal panel 10,
If these lead wires are once connected to the terminal portion of this substrate or the lead wires fixed to this substrate are used as the terminal portion so that they can be received through the driving substrate 6 of this illuminating means,
When the liquid crystal display device is rotatably attached to a portable device such as a word processor, the liquid crystal display device can be handled without damaging the power supply line or the signal line.

[0015]

As described above, since the position of the light source of the illuminating means is separated by a distance substantially corresponding to the width of the driving element protruding from the side portion of the liquid crystal panel, the heat of the light source is hard to be transmitted to the liquid crystal panel. As a result, it is extremely unlikely that the display density is changed or the contrast is partially reduced.
Further, even if the light source is separated in this way, a drive element is positioned between them, so that no useless space is provided.

Since the driving boards for the biasing means and the illuminating means are arranged on the sides of the liquid crystal panel around which the light source is not provided, the effective display surface is substantially in the center and the entire display device interior (three sides of the liquid crystal panel). Since the constituent parts are arranged in a dispersed manner, even when these are housed in the frame as in the conventional case, the display surface can be made small without making the display surface wide.

Further, even when a plurality of liquid crystal panels are used, they are arranged on one light guide plate so that unevenness in display is less likely to appear, and signal lines and the like are gathered in one place. Therefore, when the frame body is used as described above. , Or even when directly assembled into the display housing of a portable device such as a laptop personal computer, it is easy to handle even when the liquid crystal display device is rotatably supported, and the effective display surface is a liquid crystal display device. Since it is located almost in the center, the degree of freedom in design is increased in the display arrangement, shape, mounting conditions, etc. of the device using the liquid crystal display device.

[Brief description of drawings]

FIG. 1 is a plan view of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

3 is a sectional view taken along line BB of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal panel 10 2nd liquid crystal panel 2 Driving element 3 Driving element 4 Illuminating means 41 Light source 42 Light guide plate 5 Biasing means 6 Driving board for illuminating means

Claims (2)

[Claims] 1. A liquid crystal panel, a drive element disposed adjacent to the liquid crystal panel on at least two adjacent sides of the liquid crystal panel, and a light source disposed on the opposite side of the drive element on one side of the liquid crystal panel from the liquid crystal panel. A liquid crystal display device comprising: an illuminating unit that illuminates from the back surface. 2. A first liquid crystal panel having drive elements connected to at least two adjacent sides, and a second liquid crystal panel having a display area smaller than that of the first liquid crystal panel arranged in proximity to the first liquid crystal panel. A light source disposed near the driving element of the first liquid crystal panel and a light guide plate disposed on the back surfaces of the first and second liquid crystal panels; and a first liquid crystal panel in which the light source is not disposed. It is characterized in that it comprises a bias means laminated on the drive element and a drive substrate for the illumination means arranged in the vicinity of the second liquid crystal panel, and receives a power supply and a drive signal via the drive substrate for the illumination means. Liquid crystal display device.