JPH03210528A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To make it possible to use the liquid crystal display device (LCD) as both of a reflection type and a transmission type by interrupting light from a back light and forming a reflecting face at the time of using the LCD as a reflection type display device, and in the case of using the LCD as a transmission type display device, arranging a light shielding blind transmitting light from the back light between a deflection plate and the back light. CONSTITUTION:When the light shielding blind 5 is closed in the case of using the LCD as the reflection type, blades 51 are rotated so as to be vertically aligned in the figure and respective reflecting faces 52 are opposed to a liquid crystal(LC) panel 1. When the blind 5 is opened in the case of using the LCD as the transmission type, the blades 51 are rotated so as to be horizontally aligned in the figure and the panel 1 is irradiated with light radiated from the back light 4. Namely, at the time of driving the LCD by a battery, the back light 4 is turned off to use the LCD as the reflection type LCD, and at the time of driving the LCD by commercial power supply, the back light is turned on to use the LCD as the transmission type LCD. Thus, the LCD to be used as both the reflection type and the transmission type can be obtained.

Description

[Detailed Description of the Invention] [Summary] Regarding a display device used for displaying data in electronic equipment, etc., when driven by a battery, the backlight is turned off and used as a reflective liquid crystal display device, and when driven by a commercial power source, the display device is used as a reflective liquid crystal display device. aims to provide a liquid crystal display device that can be used as a transmissive liquid crystal display device by turning on a backlight, and can be used as both a reflective type and a transmissive type. In a liquid crystal display device equipped with a backlight that illuminates the entire surface of the liquid crystal panel, when used as a reflective display device, the backlight light is blocked and a reflective surface is formed, and when used as a transmissive display device, a reflective surface is formed. A light-shielding blind that transmits light from the backlight is provided between the polarizing plate and the backlight.

[Industrial application field]

The present invention relates to a display device used for displaying data in electronic equipment, and more particularly to a liquid crystal display device that can be used as either a reflective type or a transmissive type.

In recent years, transmissive liquid crystal display devices with a backlight have been used as display devices in personal computers, word processors, and the like.

However, although transmissive liquid crystal display devices have the advantage of having a bright and easy-to-read screen, they consume about 6 watts of light source power for the backlight, so they cannot be used in so-called laptop-type personal computers that are powered by batteries. .

On the other hand, laptop-type personal computers and the like are generally configured so that they can be driven not only by batteries but also by commercial power sources via adapters. Therefore, when powered by batteries, the backlight is turned off and used as a reflective liquid crystal display, and when driven by commercial power, the backlight is turned on and used as a transmissive liquid crystal display. There is a desire to realize a usable liquid crystal display device [Prior Art] FIG. 5 is a side sectional view showing a conventional liquid crystal display device.

A conventional reflective liquid crystal display device, as shown in FIG. When the screen of a reflective liquid crystal display device is viewed from the front, the light reflected by the reflective plate 3 forms a background in which characters, symbols, etc. are displayed. be done.

Furthermore, as shown in FIG. 5(b), the conventional transmission type liquid crystal display device includes a liquid crystal panel, two deflection plates 2 disposed on both sides of the liquid crystal panel l, and a panel disposed behind the deflection plates 2. When the screen of a transmissive liquid crystal display device with such a configuration is viewed from the front, the liquid crystal panel 1
Characters, symbols, etc. are displayed in the backlight 4 that illuminates the entire surface of the screen.

[Problem to be solved by the invention]

However, reflective liquid crystal display devices have a problem in that the background is light reflected by a reflector, and the contrast ratio with the background decreases in places with poor surrounding lighting, making it difficult to see characters and symbols displayed on the screen. In addition, the background of a transmissive LCD device is the light emitted by the backlight, so it is not affected by surrounding lighting (it is possible to create an easy-to-read screen, but the light source for the backlight only uses about 6 watts of power). There is a problem in that it cannot be applied to portable devices that are powered by batteries.

The purpose of the present invention is to turn off the backlight and use it as a reflective type liquid crystal display device when driven by batteries, and to use it as a reflective type liquid crystal display device by turning on the backlight when driven by commercial power. An object of the present invention is to provide a liquid crystal display device that can also be used as a transmissive type.

[Means to solve the problem]

FIG. 1 is a side sectional view showing the principle of a liquid crystal display device according to the present invention. The same objects are represented by the same symbols throughout the figures.

The above problem arises when using a liquid crystal display device that is equipped with a liquid crystal panel, a polarizing plate disposed on both sides of the liquid crystal panel, and a backlight that illuminates the entire surface of the liquid crystal panel. A light-shielding blind 5 is formed with a reflective surface and blocks the light from the backlight 4 when used as a transmissive display device, and is connected to the polarizing plate 2.
This is achieved by the liquid crystal display device of the present invention, which is provided between the backlight 4 and the backlight 4.

[For production]

In Figure 1, when used as a reflective display device, a reflective surface is formed that blocks the light of the backlight, and when used as a transmissive display device, a light-shielding blind that passes the backlight light is formed with a polarizing plate. By providing it between the backlight and the backlight, it becomes possible to switch the illumination, and it is possible to realize a liquid crystal display device that can be used as either a reflective type or a transmissive type.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 2 is a side sectional view showing a first embodiment of the invention, FIG. 3 is a side sectional view showing a second embodiment of the invention, and FIG. 4 is a side sectional view showing a modification of the invention. It is.

In FIG. 1, the liquid crystal display device according to the present invention includes a liquid crystal panel 1, two deflection plates 2 disposed on both sides of the liquid crystal panel 1, and two deflection plates 2 disposed behind the deflection plates 2, which cover the entire surface of the liquid crystal panel 1. It has a backlight 4 that emits light, and a light-shielding blind 5 is provided between the deflection plate 2 and the backlight 4. The light-shielding blind 5 includes a plurality of rotatable blades 51, and a reflective surface 52 made of a metal film or the like is formed on the surface of the blades 51 facing the liquid crystal panel 1.

When the liquid crystal display device is used as a reflective type, by closing the light-shielding blind 5, the blades 51 are rotated in a direction perpendicular to the figure, so that each reflective surface 52 faces the liquid crystal panel 1. Furthermore, when the liquid crystal display device is used as a transmissive type, by opening the light-shielding blind 5, the blades 5
The backlight 4 illuminates the liquid crystal panel 1 by rotating in the direction in which the backlight 1 becomes horizontal in the figure.

In other words, when powered by batteries, the backlight is turned off and used as a reflective liquid crystal display, and when driven by commercial power, the backlight is turned on and used as a transmissive liquid crystal display. It is possible to realize a liquid crystal display device that can be used as a liquid crystal display device.

In the first embodiment of the liquid crystal display device according to the present invention, as shown in FIG. 2, a light-shielding blind 5 surrounds a fixed plate 53 and a movable plate 54 made of a transparent material, and the sides of the fixed plate 53 and the movable plate 54. It is composed of a flexible sealing material 55 and a liquid reflector (for example, a liquid containing a plastic flake deposited with AI or A1, mercury, etc.) 56 filled between a fixed plate 53 and a movable plate 54.

When the liquid crystal display device is used as a reflective type, the light shielding blind 5 is closed. That is, when the movable plate 54 is opposed to the fixed plate 53 with a small space between them, the reflector 56 spreads over the entire surface of the light-shielding blind 5 due to capillary action, forming a reflective surface. Further, when the liquid crystal display device is used as a transmissive type, the light shielding blind 5 is opened.

That is, when the space between the fixed plate 53 and the movable plate 54 is opened in a ■ shape, the reflector 56 falls, and the reflective surface disappears, causing the backlight 4
illuminates the liquid crystal panel l.

Further, in a second embodiment of the liquid crystal display device according to the present invention, as shown in FIG. A reflective surface 5 made of a metal film on a part of the
It has 8. When the liquid crystal display device is used as a reflective type, the light shielding blind 5 is closed. That is, the endless belt 57
is moved so that the reflective surface 58 faces the liquid crystal panel 1, and when the liquid crystal display device is used as a transmission type, the light-shielding blind 5 is opened. That is, the endless belt 57 is moved so that the transparent portion faces the liquid crystal panel 1.

The liquid crystal display device shown in FIG. 4 is a modification of the second embodiment, and a removable reflective plate 59 is used as the light-shielding blind 5. When the liquid crystal display device is used as a reflective type, the light-shielding blind 5 is closed. .

That is, a reflection plate 59 is inserted between the deflection plate 2 and the backlight 4. Further, when the liquid crystal display device is used as a transmissive type, the light shielding blind 5 is opened. That is, the configuration is such that the reflector plate 59 is removed from between the deflection plate 2 and the backlight 4.

In this way, when making a reflective display device, a reflective surface is formed to block the light from the backlight, and when making a transmissive display device, a light-blocking blind is used to pass the light from the backlight, and a light-blocking blind is used between the polarizing plate and the backlight. By providing the space between the two, it becomes possible to switch the illumination, and it is possible to realize a liquid crystal display device that can be used as either a reflective type or a transmissive type.

〔Effect of the invention〕

As described above, according to the present invention, when driven by batteries, the backlight is turned off and used as a reflective liquid crystal display device, and when driven by commercial power, the backlight is turned on and used as a transmissive liquid crystal display device. It is possible to provide a liquid crystal display device that can be used both as a type and as a transmission type.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing the principle of a liquid crystal display device according to the invention, FIG. 2 is a side sectional view showing a first embodiment of the invention, and FIG. 3 is a side sectional view showing a second embodiment of the invention. 4 is a side sectional view showing a modification of the present invention, and FIG. 5 is a side sectional view showing a conventional liquid crystal display device. In the figure, 1 is a liquid crystal panel, 4 is a backlight, 51 is a blade, 53 is a fixing plate, 55 is a sealing material, 57 is an endless belt, and 59 is a reflecting plate. 2 is a deflection plate, 5 is a light-blocking blind, 52 is a reflective surface, 54 is a movable plate, 56 is a liquid reflector, 58 is a reflective surface,

Claims (1)

[Claims] In a liquid crystal display device equipped with a liquid crystal panel, polarizing plates arranged on both sides of the liquid crystal panel, and a backlight that illuminates the entire surface of the liquid crystal panel, when used as a reflective display device, the backlight (4) is A light-shielding blind (5) that blocks light and has a reflective surface formed thereon, and that allows light from the backlight (4) to pass through when used as a transmissive display device.
A liquid crystal display device, characterized in that it is provided between the polarizing plate (2) and the backlight (4).