JPH0437789A - Method and device for driving liquid crystal display panel - Google Patents

Abstract

PURPOSE:To decrease drivers which output scanning signals by distributing and outputting the scanning signal outputted by a common driver to plural common electrodes in specific order in the liquid crystal display panel where the common electrodes and plural segment electrodes are provided crossing one another. CONSTITUTION:A switching circuit 25 is provided between the common driver 26 and liquid crystal display panel 30 to distribute the scanning signals SS to the doubled common electrodes COM on a time-division base and a switching circuit 28 is provided between the segment electrodes and liquid crystal panel 30 to distribute image data GD to the doubled segment electrodes SEG on a time-division base, thereby increasing the resolution of the liquid crystal display panel 24 twice without increasing the common driver 26 nor segment driver 29. Further, the switching circuits 23 and 28 may be formed on the liquid crystal display panel by using, for example, TFTs (thin film transistor) or COG.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application J This invention relates to a method and device for driving a liquid crystal display panel suitable for use in computers, liquid crystal televisions, and the like.

"Conventional technology" In recent years, computer display devices, LCD televisions, etc.
Liquid crystal display panels are beginning to be used to reduce size and reduce power consumption. FIG. 9 is a block diagram showing the configuration of a conventional liquid crystal display panel and its driving device. In this figure, the main body of a computer (the path shown) is
Vertical synchronization signal Vgrwc1 Horizontal synchronization signal Hsrscs
A clock signal CLK and image data CD are supplied to the control circuit 10. This control circuit 10 is
C1 horizontal synchronization signal H8YHc to the above vertical synchronization signal Vgy
and common driver 1 according to clock signal CLK.
The liquid crystal display panel 13 that drives the segment electrodes 1 and 1 and the segment driver 12 is of a simple matrix type and is constructed by intersecting a plurality of segment electrodes SEG and common electrodes COM. The mutually intersecting portions become pixels of the liquid crystal display panel 13. In such a liquid crystal display panel 13, a scanning signal SS is sequentially supplied to the common electrode COM via the control circuit IO or the common driver 11, and image data C is supplied to the segment electrode SEG via the segment driver 12.
Display is performed by applying a predetermined voltage to the pixel at the position to be displayed by supplying D.

In addition, in order to display a screen having 640*400 pixels, for example, as shown in FIG. 10(a), each
A common driver 1la11b supplies scanning signals SS to 200 upper and lower common electrodes COM, and image data GD is supplied to 640 segment electrodes SEG, which are provided above and below the display panel 13a and intersect with the common electrodes COM.
Segment driver 12. ,．． 12□...
・There is a system in which the display screen is divided into upper and lower halves with 124, .

"Problem to be Solved by the Invention" By the way, in the above-mentioned liquid crystal display panel, as shown in FIG. 10(b), it is possible to increase the number of electrodes to achieve high resolution (
+280*800 pixels) to 1. If this is attempted, the number of drivers for driving the panel and the number of input lines to the panel (connection lines between the segment electrodes and common electrodes and each driver) will increase. That is, in order to achieve high resolution, the electrode density must be increased and the pitch between the electrodes must be decreased. However, as the density of input lines to a liquid crystal display panel increases, it becomes difficult to mount a driver on each electrode. Furthermore, even if the number of electrodes is increased to achieve high resolution, the number of driver ICs mounted increases in proportion to the number of electrodes, resulting in the problem that the liquid crystal display panel side becomes larger and the weight increases.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for driving a liquid crystal display panel and an apparatus therefor, which can reduce the size and weight of the liquid crystal display panel.

"Means for Solving the Problem" In order to solve the above-mentioned problem, in the invention according to claim 1, a plurality of common electrodes and a plurality of segment electrodes intersect with each other, and a common driver drives the plurality of common electrodes. In a liquid crystal display panel in which a scanning signal is sequentially supplied to the plurality of segment electrodes and image data is supplied to the plurality of segment electrodes by a segment driver, the scanning signal outputted by the common driver is supplied to the plurality of common electrodes in a predetermined order. In the invention according to claim 2, the liquid crystal display according to claim 1 is characterized in that the image data to be displayed at the position of the common electrode to which the scanning signal is supplied is outputted to the segment electrode. In the panel driving method, the image data output by the segment driver is distributed and outputted to the plurality of segment electrodes in a predetermined order. In a liquid crystal display panel driving device that sequentially outputs scanning signals to the plurality of common electrodes and outputs image data to the plurality of segment electrodes for a liquid crystal display panel formed by intersecting segment electrodes, a control means for outputting the scanning signal, the image data, and a common electrode selection control signal for selecting a common electrode to which the permanent scanning signal is to be supplied according to timing; and an output smaller than the number of the common electrodes. a common driver having an end and sequentially outputting the scanning signal outputted by the control means from the output end; a segment driver supplying image data outputted by the control means to the plurality of segment electrodes; and a plurality of switching elements. and a common switching means for distributing and outputting the scanning signal outputted by the common driver to the plurality of common electrodes in a predetermined order based on the common electrode selection control signal. In the invention according to claim 4, in the liquid crystal display panel driving device according to claim 3, the control means controls segment electrode selection for selecting the segment electrode to which the image data is to be supplied at the predetermined timing. outputting a control signal, the segment driver has a plurality of output ends smaller than the number of the segment electrodes, and sequentially outputs the image data output by the notation control means from the plurality of output ends, and the common - In addition to the switching means, it is characterized by comprising a segment switching means that distributes and outputs the image data output by the segment driver to the plurality of segment electrodes in a predetermined order based on the segment electrode selection control signal. do.

"Operation" According to the invention described in claim 1, for a liquid crystal display panel formed by crossing a plurality of common electrodes and a plurality of segment electrodes, a scanning signal outputted by a common driver is transmitted to the plurality of common electrodes. Sort and output in a predetermined order. Therefore, the number of drivers that output scanning signals can be reduced.

According to the invention as claimed in claim 2, claim! In the method for driving a liquid crystal display panel described above, image data outputted by the segment driver is distributed and outputted to the plurality of segment electrodes in a predetermined order. Therefore, the number of drivers that output image data can be reduced.

According to the invention set forth in claim 3, the common switching means selects a plurality of scanning signals outputted by a common driver having fewer output terminals than the number of common electrodes, based on a common electrode selection control signal outputted by the control means. The signals are distributed and output to the common electrodes in a predetermined order.

According to the invention set forth in claim 4, in the single-movement device for a liquid crystal display panel set forth in claim 3, the segment switching means selects a number of segment electrodes smaller than the number of segment electrodes based on a segment electrode selection control signal outputted by the control means. Image data output by a segment driver having an output end is distributed and output to a plurality of segment electrodes in a predetermined order.

Embodiment J Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In this figure, the liquid crystal display panel 19 has twice the resolution of the conventional liquid crystal display panel 13a (
1280*800 pixels). 20 is a control circuit which, according to a predetermined clock signal CLK,
The scanning signal SS, image data GD and control signal C5 are sent to common drivers 21 a, 2 l b, segment drivers 22, . 22111+”・・・22.11
,22,. 22 Ilf, -...22bn, supplied to the switching circuit 23. Each common driver 21
The output terminals of a and 21b are connected one-to-one to the input terminal of the switching circuit 23, and output the scanning signal SS at a predetermined timing. This timing will be described later. The switching circuit 23 includes a common driver 21a
, 40 equal to the output terminal 0UTI~0UT400 of 21b
0 switching elements SW −+ , SW −
t, ...... It is composed of 5W-400 (
(See Figure 2). Each switching element sw-, -5w-4
゜. alternately outputs the scanning signal SS supplied to each input terminal to either one of the two output terminals according to the control signal C5. In addition, each switching element SW□~sw
-4o.

The switching operations are performed synchronously. The output ends of this switching circuit 23 are connected in order to the common electrode COM of the liquid crystal display panel I9. That is, the switching circuit 23 has common drivers 21a and 21
The output ends of the electrodes b are alternately connected to the odd-numbered and even-numbered common electrodes COM. Segment drivers 221, ~221, and 22□~22Ilfi
As shown in FIGS. 1 and 3, these are provided above and below the liquid crystal display panel 24, and in order to provide comb-shaped wiring for every other segment electrode SEG,
2. l~22. , , are odd numbered segment electrodes 5EG1
．． 5EG3.・・・・・・Connected to 5EG1279,
Lower drivers 22bI to 22I, segment electrodes 5EG2, 5EG4 . ...SEG
1280. In this way, by making the segment electrodes shoe-shaped, the number of input lines to the liquid crystal display panel 19 can be divided into upper and lower sections, so that a segment driver can be mounted.

According to the above-described configuration, first, the control circuit 20 supplies the control signal C8 to the switching circuit 23. The switching circuit 23 includes all switching elements sw-, -sw-, as shown in the conceptual diagram shown in FIG. 4(3). .

is one output end side, for example, an odd numbered common electrode COMI
, C0M3. ...Switch to the side. Next, the control circuit 20 sends the scanning signal SS to the common driver 21.
a, 21b. Common driver 21i, 21b
synchronizes with the vertical synchronization signal V and first outputs the scanning signal SS from the output terminal 0UTI. That is, the scanning signal SS
is supplied to the common electrode COMI. Next, the control circuit 20 transfers the image data CD to the segment driver 2.
2□〜22. , , and 22b□~22,. supply to Next, the scanning signal SS is outputted from the output terminal 0UT2.

That is, the scanning signal SS is supplied to the common electrode C0M3. The control circuit 20 then controls the image data C.
D to segment drivers 22.1 to 221n and 22
, ~22. Supply to l+.

Thereafter, the control circuit 20 sequentially sends the scanning signal SS to the output terminals 0UT3 and 0UT3, as shown in the conceptual diagram shown in FIG. 5(a).
LtT4...0 Output from UT400. Therefore, the scanning signal SS is sequentially applied to the switching element s w-
,,sw-,...SW-aoo to the odd-numbered common electrode C0M5. C0M7.・・・・・・C0
Supplied to M399. Then, each time the common electrode to which the scanning signal SS is supplied is sequentially changed, the control circuit 20
is the common electrode C0M1 (i=1.3.5,...
The image data GD for 399) is sent to the segment driver 22. , ~22. n and 22°, ~22o. This pointed, odd-numbered common electrode COM
I, C0M3. ... A screen consisting of COMI 279 (odd frame) is displayed.

Next, the control circuit 20 supplies the control signal C8 to the switching circuit 23, and all the switching elements SW-
,~SW, □4°. to the other output end side, that is, the even numbered common electrode C0M2. C0M4. -9°, C0M40
Switch to the 0 side (see the conceptual diagram in FIG. 4(b)). Next, the control circuit 2o first supplies the scanning signal SS to the common drivers 21a and 2tb, and outputs the scanning signal SS to the output terminal OUT.
Output from +. The scanning signal SS is the switching element SW.
-, is supplied to the common electrode COM2 via. Next, the control circuit 20 transfers the image data CD to the segment driver 22. I~22. Il and 22b, ~22
Supply to bn. Therefore, the image data CD is common electrode C0M2+7) segment electrode SEG 1-9E
Supplied to G1280. Next, the common driver 21
a, 2 l b output the scanning signal SS from the output terminal 0UT2 and supply it to the common electrode C0M4. The control circuit 20 then supplies the image data CD to the segment drivers 2211-22□ and 22bl-22o. Therefore, the image data GD is the common electrode C0M.
4 segment electrodes 5EGI to 5EG1280.

Thereafter, the control circuit 20 sequentially sends the scanning signal SS to the output terminals 0UT3, . O
[JT4...0 Output from UT400. Therefore, the scanning signal SS is applied to the even numbered common electrode C0M6.
．． C0M8. ...Supplied to C0M400. Then, each time the common electrode to which the scanning signal SS is supplied changes sequentially, the control circuit 20 controls the common electrode C0M1.
Image data CD for (i-2, 4, 6°...400) is sent to the segment drivers 2211 to 22. ,
, and 22□-22. ,.

supply to In this way, the even numbered common electrode C0
M2. C0M4. . . . A screen consisting of COMI 280 (even frame) is displayed.

In this way, in this embodiment, the common driver 21i,
A switching circuit 23 is provided between 21b and the liquid crystal display panel 24, and a scanning signal SS is provided to the doubled common electrode COM.
By time-sharing the common driver 21
a, 21b without increasing the liquid crystal display panel 24.
The advantage is that the resolution can be doubled.

Furthermore, by arranging the segment electrodes SEG in a shoe-shape, one by one, the segment electrodes 2261 to 22a n, 22 can be connected without increasing the density of the input lines of the liquid crystal display panel 24.
The advantage is that b 1 to 22b, can be implemented.

Next, a modification of the present invention will be described with reference to the block diagram shown in FIG. In this figure, 25 is a switching circuit similar to the switching circuit 23 described above, and has n switching elements SW equal to the number of output terminals of the common driver 26.

,,SW,...5Wa-1.

This switching circuit 25 is controlled by a clock signal cL1 output from a control circuit 27. 28 is a switching circuit provided between the segment driver 29 and the liquid crystal display panel 30, and has m switching elements S equal to the number of output terminals of the segment driver 29.
W br , SW -t , SW
It is composed of ゎ. Switching element S W b
One end of -+~5Wb-s is connected to each of the output ends of the two segment drivers, and the image data GD supplied to each input end is sent to the two segments according to the clock signal CL2 output from the control circuit 27. It is output alternately to either one of the output terminals.

In addition, each of the switching elements 5Wb-+ to 5Wb- performs a switching operation in synchronization. Further, the output terminals of this switching circuit 28 are connected to segment electrodes SEG of the liquid crystal display panel 30 in order.

According to the above-described configuration, the control circuit 27 receives the scanning signal SS, the clock signal CLI, and the clock signal CL.
2 to the common driver 2 at the timing shown in FIG.
6. Switching circuit 25 and switching circuit 28
supply to. First, at time t shown in FIG. 7(C), the switching circuit 25 switches the odd-numbered common electrodes COMI, C0M3 . C0M
5°... side? Switch. In addition, the scanning signal s
s is output from the output terminal OUT 1 of the common driver 26.

As shown in FIG. 8, this scanning signal SS is transmitted to the common electrode COM! through the switching element 5Wb-+. supplied to The switching circuit 28 also operates at the same time 1. as shown in FIG. 7(b). , in response to the clock signal CL2, the odd-numbered segment electrodes 5EG1 as shown in FIG.
．． 5EG3 5EG5°...Switches to the side.

Therefore, the image data GD is the segment electrode 5EC.
I (see Figure 8).

5EG3, 5EG5. It is supplied to...

Next, time t! When the clock signal CL2 becomes low level (see FIG. 7(b)), the switching circuit 28 switches to the other output end side, that is, the segment electrode 5EG.
2.5EG4,5EG6. ...Switch to the side. In this case, since the clock signal CLl remains at the same level (see time t in FIG. 7(c)), the switching circuit 25 is not switched. Therefore, the image data GD is the segment electrode 5EG2 (see FIG. 8).

5EG4, 5EG6. It is supplied to...

Next, at time ts, when the clock signal CLI goes low and the clock signal CL2 goes high at the same time (see FIGS. 7(b) and 7(c)), the switching circuit 25 switches the even-numbered common electrodes C0M2. C0M4,
The switching circuit 28 switches to the odd numbered segment electrodes 5EGI, 5EG.
3,5EG5. . Furthermore, a scanning signal SS is output from the output terminal 0UTI of the common driver.

This scanning signal SS is supplied to the common electrode C0M2 via the switching element SWI. Therefore, the image data GD is the segment electrode 5EG1 (see FIG. 8).
, 5EG3, 5EG5. It is supplied to...

Next, at time t4, when the clock signal CL2 becomes low level, the switching circuit 28 switches the even numbered segment electrodes SEG2, 5EG4, 5EG6 .・・・・・・
・Switch to the side. In this case, since the clock signal CLI remains at a low level, the switching circuit 25 does not switch. That is, the scanning signal SS is supplied to the common electrode C0M2 via the switching element 5Wb-r (see the broken line of the switching element 5Wb-1 in FIG. 8). Therefore, the image data GD includes segment electrodes 5EG2 (see D in FIG. 8), 5EG4, 5EG6 .
...is supplied to...

Thereafter, the scanning signal SS is sequentially supplied from the common electrode C0M3 to COM(in), and each time the common electrode cOM to which the scanning signal SS is supplied changes, the odd-numbered segment electrodes 5EGI, 5EG3, 5EG5, .・・・・・・
...and even numbered segment electrodes 5EG2, 5EG4, 5
EG6. . . . Image data GD is alternately supplied to .

In this way, in the embodiment described above, the common driver 26
A switching circuit 25 is provided between and the liquid crystal display panel 30 to double the common electrode c.

By distributing the scanning signal SS to M in a time-division manner, and by providing a switching circuit 28 between the segment driver 29 and the liquid crystal display panel 30 and distributing the image data GD to the segment electrodes SEG, which have also doubled, in a time-division manner, the common An advantage is obtained that the resolution of the liquid crystal display panel 24 can be doubled without increasing the number of drivers 26 and segment drivers 29.

In addition, in the embodiment described above, the switching circuit 23
and 28 may be formed on the liquid crystal display panel using, for example, TpT (i! film transistor) or COG.

"Effects of the Invention" As explained above, according to the present invention, there is an advantage that the size and weight of the liquid crystal display panel can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
FIG. 2 is a conceptual diagram for explaining the operation of the switching circuit 23 of the same embodiment, FIG. 3 is a conceptual diagram for explaining the operation of the segment driver of the same embodiment, and FIG. 4 is a conceptual diagram for explaining the operation of the switching circuit 23 of the same embodiment. FIG. 5 is a conceptual diagram for explaining the operation of the circuit; FIG. 5 is an operation explanatory diagram for explaining the operation of the same embodiment; FIG. Figures (a), (b), and (c) are timing charts for explaining the operation of the second embodiment, and Fig. 8 is the configuration and operation of the switching circuit 2528 and liquid crystal display panel 30 of the second embodiment. 9 is a block diagram showing the configuration of a conventional liquid crystal display panel and its driving device, and FIG. 10 is a block diagram showing the structure of a conventional liquid crystal display panel divided into upper and lower parts and its driving device FIG. 2 is a block diagram showing the configuration. No. (common electrode selection control signal), CL 211. ,,
Clock signal (segment electrode selection control signal), CD・
...Image data, SS...Scanning signal.

Claims (4)

[Claims] (1) A plurality of common electrodes and a plurality of segment electrodes intersect, and a common driver sequentially supplies scanning signals to the plurality of common electrodes, and a segment driver supplies image data to the plurality of segment electrodes. In the liquid crystal display panel, the scanning signal outputted by the common driver is distributed and outputted to the plurality of common electrodes in a predetermined order, and the image data to be displayed at the position of the common electrode to which the scanning signal is supplied is outputted. A method for driving a liquid crystal display panel, the method comprising: outputting a signal to the segment electrode. (2) The method of driving a liquid crystal display panel according to claim 1, wherein the image data outputted by the segment driver is distributed and outputted to the plurality of segment electrodes in a predetermined order. (3) For a liquid crystal display panel formed by crossing a plurality of common electrodes and a plurality of segment electrodes, sequentially outputting scanning signals to the plurality of common electrodes and outputting image data to the plurality of segment electrodes. In a driving device for a liquid crystal display panel, a control means outputs the scanning signal, the image data, and a common electrode selection control signal for selecting a common electrode to which the scanning signal is to be supplied, according to a predetermined timing. , a common driver having fewer output ends than the number of common electrodes and sequentially outputting the scanning signals output by the control means from the output ends; and supplying image data output by the control means to the plurality of segment electrodes. and a common switching means comprising a plurality of switching elements, which distributes and outputs the scanning signal outputted by the common driver to the plurality of common electrodes in a predetermined order based on the common electrode selection control signal. A driving device for a liquid crystal display panel, comprising: (4) The control means outputs a segment electrode selection control signal for selecting a segment electrode to which the image data is to be supplied at the predetermined timing, and the segment driver is configured to output a segment electrode selection control signal for selecting a segment electrode to which the image data is to be supplied; has an output end, from which the image data output by the control means is sequentially output, and in addition to the common switching means, the image data output by the segment driver is output based on the segment electrode selection control signal. 4. The driving device for a liquid crystal display panel according to claim 3, further comprising segment switching means for distributing and outputting data to said plurality of segment electrodes in a predetermined order.