JPH02190895A - Liquid crystal display device with back light - Google Patents

Abstract

PURPOSE:To reduce power consumption to extend the use time of a battery driven device by driving an EL element only in a certain area of a display character or graphic. CONSTITUTION:When a character, a graphic, or the like will be displayed on a liquid crystal panel 3, data to be displayed is stored in a video memory 9 by the control of a CPU 8. The CPU 8 writes data to be displayed on the liquid crystal panel 3 in the video memory 9 and writes the presence or the absence of video information in the video memory 9 in an EL memory 11. A liquid crystal driving circuit 10 generates a signal for interface of the liquid crystal panel 3 and transfers contents of the video memory 9 to display them. An EL driving circuit 12 transfers a signal to a power supply control circuit 6 in accordance with contents of the EL memory 11 and flickers an EL panel 7 with one character as the unit. Thus, the power consumption is reduced and the use time of the battery driven device is extended.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid crystal display device for displaying characters, figures, etc., and more particularly to a backlit liquid crystal display device that improves visibility in a liquid crystal display.

[Prior Art] Conventionally, this type of display device with a backlight has always been in a lit state when in use, regardless of the display screen.

FIG. 4 is a block diagram of a conventional display device with a backlight of this type.

As shown in FIG. 4, in a conventional display device with a backlight, a power supply unit 1 includes a display control device 2 that is controlled by a CPU, a liquid crystal panel 3 that displays characters, figures, etc., and an EL panel. Power was directly supplied to the EL backlight 4 without using a (light bulb) element.

[Problems to be Solved by the Invention] The above-mentioned conventional display device with a backlight has the disadvantage of high power consumption because the EL is always on, and this is especially true for portable battery-powered devices. However, this has the disadvantage that the usage time is short or that a large battery is required.

[Means for Solving the Problems J] An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a display device with a backlight that can reduce power consumption and extend usage time in battery-powered devices. It is to be.

The present invention has achieved the above object, and includes a liquid crystal panel for displaying characters, figures, etc., an EL light emitting panel capable of blinking in units of one character, and storing data to be displayed on the liquid crystal panel. A liquid crystal drive circuit that displays data in the video memory on a liquid crystal panel, a memory that stores the presence or absence of character information in the video memory, an EL drive circuit that controls blinking of the EL, and a CP that controls these.
The present invention is characterized in that it has a display control m device having a

[Example] Next, a backlit display device according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of a backlit display device according to the present invention.

FIG. 2 is a detailed block diagram of a display control device used in the backlit display device of FIG. 1. FIG. 3 is a plan view showing the configuration of the EL light emitting panel according to the present invention.

As shown in FIG. 1, the backlit display device of the present invention includes a liquid crystal panel 3 that displays characters, figures, etc., and an EL light emitting panel 7 that can blink in the size of one character.
, a power supply control circuit 6 , and a display control device 5 .

As shown in FIGS. 1 and 2, the display control device 5 includes a video memory 9 that stores data to be displayed on the liquid crystal panel 3, and a video memory 9 that causes the data in the video memory 9 to be displayed on the liquid crystal panel 3. Liquid crystal drive circuit 10 and video memory 9
EL memory 11 for storing the presence or absence of character information in the E
It has a BL drive circuit 6 that controls blinking of L, and a CPU 8 that controls these.

Next, the operation of the backlit display device according to the present invention will be explained.

When displaying characters, graphics, etc. on the liquid crystal panel 3, the data to be displayed is first stored in the video memory 9 under the control of the CPU 8. As shown in FIG. 2, the CPU 8 writes data to be displayed on the liquid crystal panel 3 into the video memory 9, and at the same time writes into the EL memory 11 the presence or absence of video information in the video memory 9.

The liquid crystal drive circuit 10 generates a signal for interfacing with the liquid crystal panel 3, and also transfers the contents of the video memory 9 to the liquid crystal panel 3 for display.

The EL drive circuit #112 transfers a signal to the power supply control circuit 6 according to the contents of the EL memory 11, and blinks the EL in units of characters. A panel 7 is shown, which corresponds to the size of the liquid crystal panel used, and the EL element 14 has a size corresponding to one character on the liquid crystal display.The areas outside the broken line in FIG.
The internal configuration of the power supply control circuit 6 in FIG. 1 is shown, including a column register 15, a row register 16, a column driver 17,
It is composed of a row driver 18 and a corresponding BL element 1.
4, the supply voltage Vcc is controlled.

C Effects of the Invention J As explained above, the present invention is effective because it drives the EL element only in the area where the displayed characters or graphics are present, and can therefore reduce power consumption compared to the conventional art. This is particularly effective for battery-powered devices since it can extend the operating time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of a backlit display device according to the present invention. FIG. 2 is a detailed block diagram of a display control device used in the backlit display device of FIG. 1. FIG. 3 is a plan view showing the configuration of the EL light emitting panel according to the present invention. FIG. 4 is a block diagram of a conventional display device with a backlight of this type. 1... Power supply unit 2... Display control device 3... Liquid crystal panel 4... BL light emitting panel 5... Display control device 6... Power supply control circuit 7... EL light emitting panel 8. ...CPU 9...Video memory 0...Liquid crystal drive circuit 1...EL memory 2...EL drive circuit 4...EL element 5...Column register 6...Row register 7... ... Column driver 8 ... Row driver

Claims (1)

[Claims] A liquid crystal panel that displays characters, figures, etc., an EL light emitting panel that can flash in the size of one character,
The video memory stores the data to be displayed on the liquid crystal panel, the liquid crystal drive circuit displays the data in the video memory on the liquid crystal panel, the memory stores the presence or absence of characters and information in the video memory, and controls the blinking of the EL. 1. A liquid crystal display device with a backlight for displaying characters, figures, etc., comprising: a display control device having an EL drive circuit and a CPU that controls the same;