JPH11212518A - Controller for liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the quantity of data by changing a scan electrode waveform in the case that the same data are arranged with one line as a unit. SOLUTION: This controller for liquid crystal display device drives a liquid crystal display device having a dot matrix constitution and is provided with a display data preservation circuit 1 which preserves display data from a host computer 8, a display timing generation circuit 2 which generates a transmission of preserved data to the display device, a signal electrode generation circuit which generates display data in accordance with the timing of the display timing generation circuit 2, a scan electrode timing generation circuit 3 which generates a signal to select a scanning electrode in accordance with the timing of the display timing generation circuit 2, and a switching circuit 6 which switches the signal generated by the scan electrode timing generation circuit 3 by a switching signal from the host computer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a liquid crystal display device used in electronic equipment having a small liquid crystal display device such as a digital clock.

[0002]

2. Description of the Related Art A liquid crystal display (hereinafter abbreviated as LCD) is
Normally white is a display system in which the pixels lit on the background are black. "1" for display data
Will be displayed in black. When "0" is written in the display data, white is displayed.

The display structure of a dot matrix LCD will be described with reference to FIGS. In a dot matrix liquid crystal display device, pixels in a display portion are arranged like a grid. This is a type in which pixels arranged like the eyes of a go board are sequentially displayed for each row.

Here, a description will be given using a dot matrix LCD having two vertical dots and two horizontal dots. As shown in FIG. 3, signal electrodes are arranged vertically and scanning electrodes are arranged horizontally. A portion where the signal electrode and the scanning electrode overlap is a portion that becomes a pixel that can be turned on. From the signal electrode side, a signal waveform of whether to light or non-light the pixels in the first and second columns is simultaneously output for each column. From the scanning electrode side, a signal that determines which row the signal output from the signal electrode side is a signal is output. A selection signal is output to a selected row, and a non-selection signal is output to all unselected rows at the same time.

By using such a driving method, it is possible to drive even a dot matrix LCD in any number of rows and columns. Specifically 3
Illustrating the lighting as shown in the figure will be described using the signal waveforms of FIG.

First, the first column will be described. Since it is the first column, signal electrode waveform 1 is used for the signal electrode side. From the signal electrode waveform 1, "1" for turning on the pixel first
Generates a signal. At the same time, scan electrode waveform 1 for the first row
, The pixels in the first row and first column are turned on. 2
Since the selection signal is not output for the scanning electrode waveform 2 for the row, the pixels in the second row and the first column are not turned on.

At the next timing, a signal of "0" for turning off the pixel is generated from the signal electrode waveform 1. At the same time, since the scan electrode waveform 1 does not output a non-selection signal, the pixels in the first row and first column are not turned on regardless of the signal electrode waveform. The scanning electrode waveform 2 outputs a selection signal, but since the signal electrode waveform is “0”, the pixels in the second row and the first column are not lit. If this scanning is repeated continuously at a speed of about 60 times per second, 1
In the first row of the row, lighting and non-lighting are repeated, but the human eye sees the light as it is.

By scanning the second column in the same manner, the first row and the second column can be turned on, and the second row and the second column can be turned off. When the number of signal electrodes and the number of scanning electrodes are increased by the above means, the number of rows can be increased to 7 rows and 7 columns or more as shown in FIG.

As shown in FIG. 2, in a conventional control device for a liquid crystal display device, display data sent from a host computer 8 is stored in a display data storage circuit 1 and the stored data is stored on the basis of a signal from a display timing generation circuit 4. Only the signal is output from both the signal electrode timing generation circuit 2 and the scan electrode timing generation circuit 3 in order. Therefore, in order to turn on and off all the pixels, it is necessary to store information on all the pixels in the storage circuit 1.

[0010]

SUMMARY OF THE INVENTION Dot matrix L
In order to display a CD, display data is required for the number of pixels, which is a huge amount. In order to display all the pixels, it is necessary to send all data from the huge amount of display data storage circuits to the control device of the liquid crystal display every time.

(Object of the Invention) An object of the present invention is to provide a control device for a liquid crystal display device which can reduce the amount of data by changing the scan electrode waveform when the same data is arranged in one row. It is to be.

[0012]

In order to achieve the above object, a control device for a liquid crystal display device according to the present invention employs the following configuration.

A control device for a liquid crystal display device according to the present invention is a control device for a liquid crystal display device for driving a liquid crystal display device having a dot matrix configuration, and includes a display data storage circuit for storing display data from a host computer, A display timing generation circuit for sending the stored data to the display device, a signal electrode generation circuit for generating display data according to the timing of the display timing generation circuit, and scanning according to the timing of the display timing generation circuit A scan electrode timing generation circuit for generating a signal for selecting an electrode, and a switching circuit for switching a signal generated by the scan electrode timing generation circuit by a switching signal from a host computer are provided.

A control device for a liquid crystal display device according to the present invention is a control device for a liquid crystal display device for driving a liquid crystal display device having a dot matrix configuration. Display is performed at the same scanning timing using one line of data without having data.

In the control device for a liquid crystal display device according to the present invention, when a liquid crystal display device having a dot matrix configuration is used as a liquid crystal display device having a seven-segment configuration, the same data can be displayed by creating dedicated font data. By doing so, the data to be saved is reduced.

(Operation) The present invention has a switching circuit for switching the signal generated by the scanning electrode timing generation circuit by a switching signal from the host computer, so that the same scanning electrode timing can be generated even for different scanning electrodes. It is possible to greatly reduce the amount of display data if the same data is lined up on a line-by-line basis.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments for implementing a control device for a liquid crystal display device according to the present invention will be specifically described below with reference to the drawings. FIG. 1 is a block diagram illustrating a control device of a liquid crystal display device according to an embodiment of the present invention. The present invention will be described with reference to FIG.

(Structure description: FIG. 1) The control device 10 of the liquid crystal display device comprises a display data storage circuit 1, a signal electrode timing generation circuit 2, a scanning electrode timing generation circuit 3, a display timing generation circuit 4, and a switching circuit 6. Have been. The display data storage circuit 1 is a circuit that stores display data sent from the host computer 8.

The display timing generating circuit 4 is a circuit for determining a timing for turning on the LCD 5.
The scan electrode timing generation circuit 3 is about to generate scan electrode signals in order of the number of scan electrodes in accordance with the timing generated by the display timing generation circuit 4. FIG.
If the width is 7 dots as shown in the above, a scanning signal for 7 rows is generated.

The signal electrode timing generation circuit 2 is about to generate display data in synchronization with the scanning electrode signal. If the second and third rows and the fifth and sixth rows have the same data, the switching circuit 6 uses the switching signal 7 from the host computer 8 instead of the third row scanning signal.
The same scanning signal as in the sixth row is replaced with a fifth scanning signal instead of the sixth scanning signal.
This is a circuit that generates a scanning signal for the row.

(Explanation of Operation: FIG. 6) FIG. 6 is a timing showing that the waveforms of the scanning electrodes are different between the conventional and the present invention. In the present invention, when the second and third rows have the same display content, the fifth and sixth rows have the same display content, and the effect of the switching circuit 6 makes the second and third rows and the fifth and sixth rows the same. With the scanning electrode waveform, the same display can be performed on the second row, the third row, the fifth row, and the sixth row. Therefore, the display data on the third and sixth rows can be reduced.

(Description of Operation: FIG. 7) FIG. 7 is a diagram showing details of the switching circuit 6 of the present invention. In this drawing, horizontal 7
Explanation will be made using the case of a row. L1 to L7 on the left side of the drawing are signals generated by the scan electrode timing generation circuit 3.
L1 to L7 on the right side of the drawing are signals after passing through the switching circuit 6 of the present invention.

When the switching signal 7 from the host computer 8 enters at a high level, the AND gates 12, 14
Is selected, and the signal on the left side L2 is
5 is output to the right side L5, L6. Normally, the switching signal 7 from the host computer 8 is at a low level, and the AND gate 13 and the AND 15 are selected, so that the left L3 is output as it is to the right L3, and the left L6 is output as it is to the right L6. I have.

(Structure Description: FIG. 8) FIG. 8 is a view showing a number font of 0 to 9 in a 7-segment matrix using a matrix of 7 dots vertically and 7 dots horizontally. As can be seen from the figure, the second line and the third line, and the fifth line and the sixth line can be displayed completely the same. At this time, if the control device for the liquid crystal display device of the present invention is used, it is not necessary to have the display data on the third and sixth rows.

(Structure Description: FIG. 9) FIG. 9 is a diagram showing that when a control device of a conventional liquid crystal display device is used, 49 pixel data of 7 vertical dots and 7 horizontal dots are required.

(Structure description: FIG. 10) FIG. 10 shows that when the control device and the font of the liquid crystal display device according to the present invention are used, the data in the second and third lines, the data in the fifth and sixth lines are the same. In order for the pixel data of 7 dots vertically and 7 dots horizontally to be 3
FIG. 7 is a diagram showing that only five data are required. According to the present invention, 49 data becomes 35 data, and the display data amount can be reduced by 29%.

(Structure Description: FIG. 11) FIG. 11 shows a state in which a digital clock is displayed using a dot matrix liquid crystal having 39 horizontal dots and 7 vertical dots. At this time, if there is display data in the conventional embodiment, it is necessary to save 273 display data. In the embodiment of the present invention, if data is provided, the second and third rows and the fifth and sixth rows have the same data, so that it is not necessary to have the data of the third and sixth rows.
Only 95 pieces of display data are required.

Therefore, the display data amount can be reduced by 29%. In the case of a timepiece, it is important to reduce the amount of display data and reduce the time during which the host computer operates in order to reduce power consumption.

[0029]

As apparent from the above description, the control device of the liquid crystal display device of the present invention has a switching circuit for switching the signal generated by the scan electrode timing generation circuit by a switching signal from the host computer. The same scan electrode timing can be generated even for different scan electrodes, and if the same display data is arranged in a line, the display data amount is greatly reduced. Can be supplied to an electronic device having the liquid crystal display device.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a control device of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a control device of a liquid crystal display device according to the related art.

FIG. 3 is a diagram showing a dot matrix of two rows and two columns of the liquid crystal display device.

FIG. 4 is a signal waveform diagram for driving a 2 × 2 dot matrix of the liquid crystal display device.

FIG. 5 is a diagram showing a dot matrix of 7 rows and 7 columns of the liquid crystal display device.

FIG. 6 is a waveform chart showing the difference between the scan electrode waveforms of the liquid crystal display device according to the embodiment of the present invention and the prior art.

FIG. 7 is a diagram illustrating details of a switching circuit inside a control device of the liquid crystal display device according to the embodiment of the present invention.

FIG. 8 is a view showing numbers from 0 to 9 used in a liquid crystal display device according to an embodiment of the present invention in a font with 7 rows and 7 columns.

FIG. 9 is a diagram showing the number of pixel data in 7 rows and 7 columns in the related art.

FIG. 10 illustrates a liquid crystal display device 7 according to an embodiment of the present invention.
It is the figure which showed the number of pixel data of the 7th row.

FIG. 11 is a diagram showing a state in which a digital clock is displayed using a dot matrix liquid crystal of 39 horizontal dots and 7 vertical dots of a liquid crystal display device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 display data storage circuit 2 signal electrode timing generation circuit 3 scan electrode timing generation circuit 4 display timing generation circuit 5 liquid crystal display device 6 switching circuit 7 switching signal 8 host computer 9 control circuit of conventional liquid crystal display device 10 liquid crystal display of the present invention Control circuit of device 11 NOT gate 12 AND gate 13 AND gate 14 AND gate 15 AND gate

Claims (4)

[Claims] 1. A control device for a liquid crystal display device for driving a liquid crystal display device having a dot matrix configuration, comprising a display data storage circuit for storing display data from a host computer, and storing the stored data in the display device. A display timing generation circuit that takes a sending timing, a signal electrode generation circuit that generates display data according to the timing of the display timing generation circuit, and a scan that generates a signal that selects an electrode to be scanned according to the timing of the display timing generation circuit A control device for a liquid crystal display device, comprising: an electrode timing generation circuit; and a switching circuit that switches a signal generated by the scanning electrode timing generation circuit by a switching signal from a host computer. 2. The control device for a liquid crystal display device according to claim 1, wherein the switching circuit is constituted by a semiconductor switch. 3. A control device of a liquid crystal display device for driving a liquid crystal display device of a dot matrix configuration, wherein when there is a row in which one horizontal display data is the same, one row of data is not possessed. A control device for a liquid crystal display device, wherein a display is performed at the same scanning timing using the same. 4. When a liquid crystal display device having a dot matrix configuration is used for a liquid crystal display device having a 7 segment configuration,
A control device for a liquid crystal display device, wherein data to be stored can be reduced by creating dedicated font data so that two or more lines can be displayed with the same data.