JPH024221A - Liquid crystal backlight controller - Google Patents

Abstract

PURPOSE:To prevent the waste of a battery power source by providing a photodetector which responds to visible light on the bottom part of a photodetecting hole having an opening part on the liquid crystal display surface side of a liquid crystal plate holding tool. CONSTITUTION:There is a hole-like photodetecting hole 5 on a liquid crystal display surface 7, and there is a photodetecting device 6 on the bottom part of the hole 5. A shape of the hole 5 is like a hole, and structured so that only a light beam from the direction C vertical to the liquid crystal display surface 7 reaches directly the device 6. The output of the device 6 is brought to current amplification by an amplifier 9, inputted to a control terminal 10a of a lighting control part 10, and controls opening/closing of a switch 10b. A backlight 4 is driven by a backlight use power source 11. In such a case, sensitivity of the amplifier 9 is set so as to close the switch 10b of the lighting control part 10, when an external light by which the display contents of a liquid crystal display device 2 can be read enough even if the backlight 4 is turned off is made incident directly on the device 6. In such a way, waste of a battery power source can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a liquid crystal backlight control device, and particularly to a liquid crystal display of a transflective liquid crystal display device used as a display section of a portable information processing device operated by battery power. The present invention relates to a backlight control device.

[Conventional technology]

In conventional liquid crystal backlight control devices, turning on and off the backlight is controlled by an operator using a manual switch.

[Problem to be solved by the invention]

The conventional LCD backlight control device described above does not require the battery to be turned off, even if the conditions such as the ambient light source and the angle of the LCD screen change and the displayed content is sufficiently recognizable even when the backlight is turned off. This has the disadvantage of wasting battery power.

[Means to solve the problem]

The liquid crystal backlight control device of the present invention includes (^) a light receiving hole having an opening on the liquid crystal display surface side of the liquid crystal plate holder; (B) a light receiving element sensitive to visible light provided in the lower part; C) a control section that controls blinking of the backlight based on the output signal of the light receiving section;

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1(a) and 1(b) are front views showing one embodiment of the present invention.

The liquid crystal backlight control device shown in FIGS. 1(a) and 1(b) has a housing 3 attached to a portable information processing device 1 whose angle can be adjusted in the front-rear direction B, and a half A transmissive liquid crystal display device 2 is incorporated. A backlight 4 is provided on the back surface of the liquid crystal display device 2.

A hole-shaped light receiving hole 5 is provided on the liquid crystal display surface 7, and at the bottom of the light receiving hole 5 is a light receiving device 6 shown in FIG. Light receiving hole 5
The structure is such that only light from the direction C perpendicular to the liquid crystal display surface 7 directly reaches the light receiving device 6.

FIG. 4 is a block diagram showing the operation of the second invention.

The output of the light receiving device 6 is current amplified by an amplifier 9,
The signal is input to the control terminal 10a of the lighting control unit 10, and controls the opening and closing of the switch 10b.

The backlight 4 is driven by a backlight power source 11. The backlight power source 11 converts the DC current of the battery 8 into a backlight drive current. Switch 10b opens and closes this direct current.

The light-receiving device 6 receives enough external light to read the displayed content on the liquid crystal display device 2 even when the backlight 4 is off.
When light directly enters the switch 10 of the lighting control section 10
The sensitivity of amplifier 9 is set so as to close b.

〔Effect of the invention〕

The liquid crystal backlight control device of the present invention measures the brightness of the liquid crystal display surface and automatically turns on and off the backlight power source, which has the effect of preventing wastage of battery power.

[Brief explanation of the drawing]

Figures 1 (a> and b) are front and side views showing one embodiment of the present invention, Figure 2 is a detailed cross-sectional view of the light receiving hole shown in Figure 1, and Figure 3 illustrates the operation of the present invention. 1 is a block diagram showing: 1... Portable information processing device, 2... Liquid crystal display device, 3... Housing, 4... Backlight, 5... Light receiving hole, 6... Light receiving device, 7... Liquid crystal display surface, 8...
Battery, 9...Amplifier, 10...Lighting control unit, 11...Backlight power supply. Agent Patent Attorney Susumu Uchihara 7 Figure 2

Claims (1)

[Scope of Claims] (A) a light receiving hole having an opening on the liquid crystal display side of the liquid crystal plate holder; (B) a light receiving element sensitive to visible light provided in the lower portion; (C) the light receiving hole; A liquid crystal backlight control device comprising: a control section that controls blinking of a backlight based on an output signal of the section.