JPH04307514A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain the liquid crystal display device which allows the visual observation of a liquid crystal display panel even if a back light is not lighted according to the brightness of the external world by providing a transmission means and reflection means between the panel and a light source. CONSTITUTION:A film which is formed by integrating a transmission film 7 and reflection film 8 and has the area larger than a panel display area is inserted between the panel 1 and a diffusion plate 6. This film is so disposed as to be pulled under proper tension by a reel 9 and reel 10 installed on both sides of the back light. The reflection film 8 covers the front surface of the panel when the reel 9 is completely wound and, therefore, the liquid crystal display device of reflection provision to utilize the external light is obtd. Conversely, the transmission film 7 covers the entire surface of the panel when the reel 10 is wound and, therefore, the liquid crystal device of transmission provision to use the back light as a light source is obtd. The transmission provision and reflection provision can be automatically controlled simply by constituting the device in such a manner that the reel 10 operates when the back light is lighted and the reel 9 operates when the back light is put out.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a liquid crystal display device equipped with a cold cathode discharge tube as a light source.

0002

2. Description of the Related Art An example of a liquid crystal display device equipped with a conventional cold cathode discharge tube as a light source will be described with reference to FIGS. 6 and 7.

[0003] A liquid crystal display panel (hereinafter referred to as a panel) 1 includes a flexible tape (hereinafter referred to as COF) 2 on which an LSI for driving the panel is mounted, and a substrate (hereinafter referred to as COF) for transmitting signals necessary to drive the COF. (called PCB)3
Driven by.

On the other hand, the backlight is composed of a cold cathode discharge lamp (hereinafter referred to as CFL) 4 as a light source, a lamp house 5 made of plastic, and a diffusion plate 6 for diffusing light.

[0005] Since the polarizing plate of the panel is of a transmissive type, the display on the panel can be viewed visually only by turning on the backlight.

[0006]

However, the above-mentioned prior art has a problem in that the display on the panel cannot be viewed when the backlight is not turned on. SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and its purpose is to provide a liquid crystal display device that allows the panel display to be viewed visually without the need to turn on a backlight depending on the brightness of the outside world. be.

[0007]

[Means for Solving the Problems] The liquid crystal display device of the present invention is a liquid crystal display device equipped with a cold cathode discharge tube as a light source, and includes a transmitting means and a reflecting means between the liquid crystal display panel and the light source. It is characterized by what it did.

[0008]

[Embodiment 1] FIGS. 1 and 2 are a sectional view and a plan view showing the configuration of essential parts in an embodiment of the present invention.

A reel 9 and a reel are provided in which a film that integrates a transmitting film 7 and a reflective film 8 each having an area larger than the panel display area is inserted between the panel 1 and the diffuser plate 6, and this film is installed on both sides of the backlight. 10 so that they are pulled together with appropriate tension.

When the reel 9 is completely wound, the reflective film covers the front surface of the panel, making it a reflective-equipped liquid crystal display device that uses external light. Conversely, when the reel 10 is completely wound, the transparent film covers the entire surface of the panel. This makes it a transmissive liquid crystal display device that uses a backlight as a light source.

[0011] In order to automatically control the transmission equipment and the reflection equipment, it is sufficient to operate the reel 10 when the backlight is turned on, and to operate the reel 9 when the backlight is turned off.

[Embodiment 2] FIGS. 3 to 5 are diagrams showing the configuration of main parts in another embodiment of the present invention.

A blind shutter 11 is inserted between the panel 1 and the diffuser plate 6, in which a reflective film of 2 mm width and 100 μm thickness is disposed over the entire surface of the panel.

When the blind shutter is perpendicular to the backlight as shown in FIG. 3, it becomes a transmissive liquid crystal display device using the backlight as a light source, and conversely, when the blind shutter is perpendicular to the backlight as shown in FIG. When it is horizontal, it becomes a liquid crystal display device that is a reflective device that uses external light.

The reflective film of the blind shutter may be of any material as long as it can sufficiently reflect external light.

[0016] In order to automatically control the transmissive equipment and the reflective equipment, it is sufficient to open and close the blind shutter in conjunction with the on/off of the backlight.

[0017]

Effects of the Invention As described above, according to the present invention, since it is possible to select either the transmitting means or the reflecting means between the panel and the backlight, when the amount of light from the outside is sufficient, the light is reflected. It is now possible to select equipment and see the panel display without turning on the backlight, making it easier for users to view the panel display for long periods of time without tiring their eyes. In addition, since power can be saved in liquid crystal display devices that use batteries or rechargeable batteries as power sources, it has become possible to drive them for long periods of time.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing Embodiment 1 of the present invention.

FIG. 2 is a plan view showing Embodiment 1 of the present invention.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is a sectional view showing a second embodiment of the present invention.

FIG. 5 is a plan view showing a second embodiment of the present invention.

FIG. 6 is a cross-sectional view of a conventional liquid crystal display device.

FIG. 7 is a plan view of a conventional liquid crystal display device.

[Explanation of symbols]

1. panel 2. C.O.F. 3. PCB 4. C.F.L. 5. lamp house 6. Diffusion plate 7. transparent film 8. reflective film 9. reel 10. reel 11. blind shutter

Claims (1)

[Claims] 1. A liquid crystal display device equipped with a cold cathode discharge tube as a light source, characterized in that a transmission means and a reflection means are provided between the liquid crystal display panel and the light source.