JPH01320880A - Driving method for liquid crystal panel - Google Patents

Abstract

PURPOSE:To quickly update the display on a screen and to prevent unnaturalness of display update by driving a liquid crystal panel so that the liquid crystal panel can follow up the change of a video signal. CONSTITUTION:A data comparator 4 compares data outputted from a data converter 1 with data read out from a memory 2 and judges whether data is changed or not in each line. The output of this data comparator 4 is inputted to a change line monitoring circuit 5 to monitor whether the picture is charged or not with one line as the unit in each field, and monitor results are stored in a change line position memory 6. When results stored in this memory 6 indicate that a change line exists, level '1' is outputted and is applied to a liquid crystal panel driving control part 7, and the picture on this change line is erased, and the data in this erased line in the change line position memory 6 is read out from the memory 2, where picture data is stored, and is written on the liquid crystal panel.

Description

[Detailed Description of the Invention] [Summary] Regarding a display drive method using a simple matrix-controlled phase change type liquid crystal panel, the screen display can be updated more quickly by driving the liquid crystal panel so that it can follow changes in the video signal. In order to eliminate the unnaturalness of the display update, the digital video signal is converted into a binary signal by a data converter and stored in the memory, and the output of the stored memory and the data stored in the memory are converted into a binary signal. A device that updates a screen by controlling a liquid crystal panel drive control unit using an output obtained by comparing frame-delayed data with a data comparator.

whether the data comparator outputs a change, or “
A change line that inputs one of the signals and the re-output of the timing signal output by the address generator and monitors whether there is a screen change on a line-by-line basis for each field. A monitoring circuit and a changed line position memory for storing the results monitored by the changed line monitoring circuit are provided, and when the output signal of the changed line monitoring circuit stored in the changed line position memory is “yes”, the change is detected. After erasing the erased line, the liquid crystal panel drive control section is controlled to read and write data on the erased line from the memory, thereby performing driving that can follow changes in the video signal.

[Industrial application field]

The present invention relates to a display driving method using a phase change type liquid crystal panel with simple matrix control.

Recently, due to the shift to OA for meetings and education, traditional blackboards and OH
There is a growing demand for large displays that can replace the P.

As one method to meet this demand, a projection type liquid crystal display using a phase change type liquid crystal as a light valve has come into use.

In the conventional method, when displaying a video signal on this phase change type liquid crystal panel, the usual method was to perform writing after erasing the entire surface of the liquid crystal panel in response to a change in the video signal.

However, rewriting one screen using this method takes about 1 to 2
Moreover, even if a portion of the screen is changed, the entire screen must be rewritten, which creates an unnatural situation in which the entire screen is temporarily blank when updating the display. Therefore, there is a need to improve this unnaturalness at the time of updating.

[Conventional technology]

FIG. 4 is a diagram showing the configuration of a conventional embodiment.

In the figure, 1 is a data converter, 2 is a memory, 3 is an address generation section, 4 is a data comparator, and 7 is a liquid crystal panel drive control section. Further, FIG. 5 is a diagram showing a processing procedure of a conventional embodiment.

The RGB color signals of the digital video signal are sent to the data converter 1.
Input the video signal into the
It is converted into a binary signal indicating the color level. At the same time,
The vertical synchronization signal Vs and horizontal synchronization signal Hs in the digital video signal are input to the address generation section 3, which outputs an address signal and a sampling clock, as well as timing signals of frame signals and line signals for monitoring changed lines. .

The binary signal from the data converter 1 is manually stored in the memory 2 as data for one field. The address to which the data is input is determined by an address signal from the address generation section 3, and is controlled by the sampling clock output from the address generation section 3 for each frame and stored at a desired address.

Next, in the data comparator 4, the timing signal of the address generator 3 from the memory 2 is the output data read out and the output data output from the data converter 1, and
The output data delayed by one frame from the output data is compared dot by dot, and the presence or absence of a changed frame is determined for each line.At this time, if the re-output is the same, the line's It determines that there is no change, simply outputs a level 0' indicating that the data matches, and does not update the screen.However, if there is a difference in the re-output, there is a change.
It is determined that this is the case, and a level "1" indicating a mismatch is output.

The liquid crystal panel drive control unit 7 outputs a liquid crystal panel drive signal when the output from the data comparator 4 is at level "1", first erases screen data for one field, and then erases one field to be input. Full-page writing is performed using the data for 20 minutes. Conversely, when the output from the data comparator 4 is at level '0°, it is assumed that there is no change in the screen and the previous screen is continued and displayed.

Note that FIG. 3(A) is a diagram showing the updating state of screen erasing and writing in the conventional method. As shown in the figure, when updating a line that was displayed as ``KakiKukeKo'' on one screen, the entire screen is erased and updated.

In the conventional method described above, screen updates are determined on a frame-by-frame basis and erased and written.
~2 seconds was required.

[Problem to be solved by the invention]

As described above, in the conventional method, it takes about 1 to 2 seconds to update the screen, and when the screen is updated, the entire screen disappears, which is unnatural.

An object of the present invention is to speed up screen display updates and eliminate unnaturalness in display updates by driving a liquid crystal panel so that it can follow changes in video signals.

[Means to solve the problem]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention.

In the figure, 1 is a data converter, which converts a digital video signal into a binary signal and outputs the data to be stored in the address of the memory 2 designated by the address generator 3, and 4 is a data comparator. 5 is a change line monitoring circuit that compares the output of the data converter 1 and the data after one frame output from the memory 2; By manually re-outputting either the `` or '' signal and the timing signal from the address generator 3, it is possible to determine whether the screen change line is present or not for each line for each field. The monitoring device 6 is a changed line position memory, which stores the results monitored by the changed line monitoring circuit 5.

In the liquid crystal panel drive control section 7, when the result of monitoring by the changed line monitoring circuit 5 is "Yes", it erases only the changed line and stores the erased line from the memory 2. The screen is updated so that it can follow changes in the video signal by reading and writing data in the video signal.

[For production]

As shown in FIG. 1, the present invention inputs the output of the data comparator 4 to a changed line monitoring circuit 5, and monitors whether the changed line on the screen is present or absent on a line-by-line basis for each field. Then, the monitored results are stored in the changed line position memory 6.

Furthermore, when the result stored in the changed line position memory 6 is that the changed line is 'existed', a level of '1' is output and applied to the liquid crystal panel drive control section 7, the screen is first erased for the changed line, and then the screen is erased. The data on the line erased in the changed line position memory 6 is read from the memory 2 where image data is stored, and is written to the liquid crystal panel to update the screen [Example] 1st The figure is a diagram showing the configuration of an embodiment of the present invention. In the figure, ■ is a data converter, 2 is a memory, 3 is an address generator, 4 is a data comparator, 5 is a changed line monitoring circuit, 6 is a changed line position memory, and 7 is a liquid crystal panel drive control unit. It is. Note that FIG. 2 is a diagram showing a processing procedure of an embodiment of the present invention. In the following description, those having the same configuration as the conventional example will be explained in a simplified manner.

The RGB color signals of the digital video signal are taken into the data converter 1, converted into binary signals of °1' and "0", input to the memory 2, and stored as data for one field. The address at which the data is input is determined by the address signal from the address generator 3.

At the same time, the vertical synchronization signal V in the digital video signal
s and the horizontal synchronization signal Hs are input to the address generation section 3, which outputs an address signal and a sampling clock, and also outputs timing signals of frame signals and line signals for monitoring changed lines.

Next, the data comparator 4 compares the data read from the memory 2 and the data output from the data converter 1 frame by frame, and determines whether there is a change or not for each line. At this time, if the re-outputs are the same, it is determined that there is no change line and outputs a level '0° indicating data matching.However, if there is a difference in the re-outputs, , it is determined that there is a change, and a level "1°" indicating a mismatch is output.

The changed line monitoring circuit 5 inputs the level "1" output from the data comparator 4 and the timing signal from the address generator 3, and monitors the "existence" of the changed line on the screen line by line for each field. ' or ' is monitored and the monitored result is stored in the changed line position memory 6.

In addition, in the liquid crystal panel drive control section 7, when the output of the result stored in the changed line position memory 6 is ``Yes'', first, only one line of the changed line is erased, and the memory 2 storing the image data is erased. The data in the erased line is read from the changed line position memory 6 and written to the liquid crystal panel to update the screen. Note that when there is no output from the changed line position memory 6, the screen is not updated and continues to be displayed as the previous screen.

Note that FIG. 3(B) is a diagram showing the update state of screen erasing and writing according to the present invention. However, FIG. 3A shows an updated state of screen erasing and writing using the conventional method. In the present invention, as shown in FIG. 3(B), when updating the line that was displayed as "Kakikukeko",
This indicates that the corresponding line will be erased and written later to update the screen.

That is, since the present invention is a method of updating by erasing and writing on a line-by-line basis, it is possible to shorten the display time of a screen that lacks information that is not displayed, and to avoid unnaturalness in display updates. can.

[Effects of the Invention] As explained above, according to the present invention, when displaying a video signal by driving a liquid crystal panel device, the display time of a screen lacking information can be shortened, and unnatural display updates can be reduced. It is possible to eliminate the problem.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the configuration of an embodiment of the present invention, Fig. 2 is a diagram showing the processing procedure of an embodiment of the invention, and Fig. 3 is a comparison of screen updating between the method of the present invention and the conventional method. FIG. 4 is a diagram showing the configuration of a conventional embodiment, and FIG. 5 is a diagram showing a processing procedure of a conventional embodiment. In the figure, 1 is a data converter, 2 is a memory, 3 is an address generation section, 4 is a data comparator, 5 is a changed line monitoring circuit, 6 is a changed line position memory, and 7 is a liquid crystal panel drive control section. glJ/l-Bonse gshikororihibarai Figure 5 Nibu T diagram

Claims (1)

[Claims] A digital video signal is converted into a binary signal by a data converter (1) and stored in a memory (2), and the output of the stored memory (2) and the stored output of the memory (2) are The data comparator (4) compares the data with the data delayed by one frame and uses the output obtained from the liquid crystal panel drive control unit (
7), which updates the screen by controlling the data comparator (4), which outputs a signal indicating whether there is a change or not, and an address generator (3).
Input both outputs of the timing signal output by , and check whether the screen changes for each line for each field.
A changed line monitoring circuit (5) that monitors the changed line, and a changed line position memory (6) that stores the results monitored by the changed line monitoring circuit (5), and the changed line position memory (6) stores the results of monitoring. The change line monitoring circuit (5
) is 'present', the liquid crystal panel drive control unit (7) reads and writes data on the erased line from the memory (2) after erasing the changed line. ) to perform driving that can follow changes in a video signal.