JPH01320881A - Driving control method for liquid crystal panel - Google Patents

Abstract

PURPOSE:To quickly update a picture by distinguishing data whose erasing is required or the other data from each other and allowing the latter data to remain and changing the picture by overwriting to update the picture. CONSTITUTION:The output of a data converter 1 is compared with the output of a memory 2 by a data comparator 8 to discriminate the change from display to non-display or the other change by comparison, and the comparison output is inputted to a change line monitor circuit 9 to monitor whether the change of the video signal requires erase with a line as the unit or not, and the monitor result is stored in a change line information memory 10. The output of the data converter 1 is compared with the output of the memory 2 by a data comparator 4 to discriminate whether the picture is changed or not by comparison, and the comparison output is inputted to a change line monitor circuit 5, and information indicating whether the video signal is changed with a line as the unit or not is stored in a change line position memory 6. A liquid crystal panel driving control part 7 changes the display based on data in memories 10 and 6 by only write or erase and write.

Description

[Detailed Description of the Invention] [Summary] Regarding a drive control method for a simple matrix-controlled phase change type liquid crystal panel, an object of the present invention is to speed up screen updating by performing drive control that allows the liquid crystal panel to follow changes in video signals. For the purpose of a first data comparator that compares the output of the data converter and the output of the memory to determine whether there is a change in each dot unit; The comparison output of the first data comparator and the timing signal output by the address generation section are
a changed line position memory that inputs the input to the changed line monitoring circuit of the field and monitors the presence or absence of a change in line units for each field and stores the monitoring results; and the output of the data converter and the memory. Compare the outputs and monitor whether the change in data in dot units for each field is from "Displayed to Displayed Amount" or from "Displayed to Displayed Amount" a second data comparator for
The output of the second data comparator and the timing signal output by the address generation section are input, and a second changed line monitoring circuit monitors whether or not the changed data requires erasing line by line. and a changed line information memory for storing the monitored results, inputting the re-output of the changed line position memory and the changed line information memory to the liquid crystal panel drive control section, and updating the data only by writing, The configuration is configured so that the screen is updated by selecting one of the following: or requiring erasing and writing.

[Industrial application field]

The present invention relates to a drive control method for a phase change type liquid crystal panel using simple IJ control.

Recently, due to the shift to OA in meetings and education, traditional blackboards and ○H
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.

When updating the screen by driving this phase change type liquid crystal panel, conventionally a method has been used in which the presence or absence of a change is compared line by line and the screen is updated for each changed line.

Therefore, it takes about 0.05 seconds/number of changed lines to rewrite the screen, and it is difficult to say that the rewriting of the liquid crystal follows changes in the video signal.

This causes considerable unnaturalness when updating the screen, and there is a need to improve this unnaturalness.

[Conventional technology]

FIG. 4 is a diagram showing the configuration of an embodiment of the present invention. In the figure, 11 is a data converter, 12 is a memory, 13 is an address generator, 14 is a data comparator, 15 is a changed line monitoring circuit, 16 is a changed line position memory, and 17 is a changed line position memory.
is a liquid crystal panel drive control section. Note that FIG. 5 is a diagram showing a processing procedure of a conventional embodiment. This will be explained below using FIGS. 4 and 5.

Data converter 11 converts RGB color signals of digital video signals
It is converted into a binary signal of "1' and "0" and input to the memory length and stored as one field's worth of data.The address to which this data is input is determined from the address generator 13. Determined by address signal.

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 13, which outputs an address signal and a sampling clock, and also generates both timing signals: a frame signal for frame-by-frame synchronization, and a line signal for line-by-line synchronization. Output.

Next, the data comparator 14 compares the data read from the memory 12 with the data output by the data converter 11 and delayed by one frame from the data read from the memory 12, dot by dot. Each time, it is determined whether the changed line is present or not.At this time, if the re-output is the same, it is determined whether the change has been made or not, and a level 0° is output indicating that the data match. .Furthermore, if there is a difference in the re-output, it is determined that there is a change and outputs a level ``1'' indicating non-compliance.

The changed line monitoring circuit 15 uses the information of “presence” or “absence” of change output from the data comparator 14 and the address generation unit 13.
The system inputs a timing signal from the screen to monitor the presence or absence of a screen change on a line-by-line basis for each field, and stores the monitored results in a changed line position memory.

Note that when the changed line position memory 16 outputs a level "1" indicating that a change has been made, the liquid crystal panel drive control unit 17 erases only the changed line and stores the image data. The data in the line erased by the changed line position memory 12 is read out from the memory 12, and written to the liquid crystal panel, thereby outputting a liquid crystal panel drive signal for updating the screen.

Note that when there is no change in the level "0" of the output of the data comparator 14, the liquid crystal panel displays the previous screen m times in succession and no change is made.

FIG. 6 is a diagram showing the update state of erasing and writing in the conventional method. As the character to change, change ゛car′ to “Yu”
The following is an example of updating to . 611m CB) As shown, the erase lines for erasing are 5.9.12 to 15, and the write lines shown in FIG. 6(C) are 5.9.
12 to 15, and these changes are made to complete the update. Of course, erasing and writing are performed line by line.

As described above, conventionally, all erasing and writing are performed on the changed line. For this reason, updating requires, for example, approximately 0.05 seconds/number of changed lines. Therefore, there is a strong desire to shorten this update time.

[Problem to be solved by the invention]

As described above, in the conventional method, it still takes a considerable amount of time to update the screen, and there is a desire to further speed up the update.

An object of the present invention is to speed up screen updating by performing drive control that allows a liquid crystal panel to follow changes in a video signal.

[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 stores it in the address of the memory 2 specified by the address generation section 3; 4 is a first data comparator; The output of the data converter 1 and the output of the memory 2 are compared to determine whether there is a change in each dot unit.
6 is the change line position memory,
The output of the data comparator 4 and the timing signal from the address generator 3 are input to a first change line monitoring circuit 5 to monitor whether or not there is a change in line units for each field. 8 is a second data comparator, which compares the output of the data converter 1 and the output of the memory 2, and determines the data changes in dot units. Has the change changed from “with display” to “no display”?
10 is a change line information memory, and the output of the second data comparator 8 and the timing signal outputted by the address generation section 3 are is input, and the second changed line monitoring circuit 9 monitors whether or not the changed data requires erasure on a line-by-line basis, and the result is stored.

The liquid crystal panel drive control section 7 inputs the re-output of the changed line position memory 6 and the changed line information memory 1O, and updates the data either by writing only or by erasing and writing. Configure the screen so that it is selected and the screen is updated.

[For production] □ As shown in FIG. 1, the present invention is a data converter 1.

The second data comparator 8 compares the output of the memory 2 with the output of the memory 2, and determines whether there has been a change from 'displayed' to 'displayed' or '°
After comparing whether there is a change other than “from “present” to “no display”,
The output obtained from the comparison is input to the second changed line monitoring circuit 9 to monitor whether or not the change in the video signal requires erasure in line units, and the monitoring result is stored in the changed line information memory i. Store it in months 0-10.

In addition, the output of the data converter 1 and the output of the memory 2 are compared by the first data comparator 4, and after comparing whether there is a screen change or not, the output obtained by the comparison is The input signal is input to the first changed line monitoring circuit 5 to monitor whether the video signal is changed line by line, and the monitored result is stored in the first changed line position memory 6. .

Therefore, by inputting both of the above-mentioned stored data to the liquid crystal panel drive control section 7, it is possible to select whether to change the display by writing or by erasing and writing. , it becomes possible to speed up screen updating.

〔Example〕

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention. In the figure, 1 is a data converter, 2 is a memory, 3 is an address generator, 4 is a first data comparator, 5 is a first changed line monitoring circuit, 6 is a first changed line position memory, and 7 is a first changed line position memory. 8.9.10 is a circuit of the present invention; 8 is a second data comparator; 9 is a second change line monitoring circuit; and 10 is a change line information memory.

Note that FIG. 2 is a diagram showing the processing procedure of a conventional embodiment. The contents will be explained below with reference to FIGS. 1 and 2.

The RGB color signals of the digital video signal are taken into the data converter 1, converted into binary signals of 'l° and "0", and stored in the memory 2 as data for one field. The address is determined by an 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 both timing signals: a frame signal for synchronizing one frame, and a line signal for synchronizing each line. do.

Next, the first data comparator 4 compares the data read out from the memory 2 with the data output by the data converter 1 dot by dot to determine whether there is a change. At this time, if both outputs are the same, it is determined that there is no change, a level 0 indicating that the data match is output, and the screen is not updated. However, if there is a difference between the two outputs, it is determined that a change has occurred and a level "1" indicating a mismatch is output.

The first changed line monitoring circuit 5 inputs the information on whether there is a change outputted from the first data comparator 4 and the timing signal from the address generation unit 3, and inputs the timing signal from the address generation unit 3 on a line-by-line basis for each field. The screen is monitored for the presence or absence of a change, and the result of the monitoring is stored in the changed line position memory 6.

Here, the same data is input to the second data comparator 8 in parallel with that of the first data comparator, and the content of the data is “
It is made to judge whether the change has been made from displaying to not displaying or something else. That is, it is determined whether or not the erase operation is necessary for the changed line, and a "display state signal °" is output.

The second changed line monitoring circuit 9 receives this "display state signal" and changes it into a "line unit information signal" in response to a timing signal coming from the address generation section 3. this"
The line-by-line information signal is a signal that determines whether the input video signal needs to be erased line by line or not. This "line unit information signal" is stored in the modified line information memory 10 as data for frame (1).

In the liquid crystal panel drive control unit 7, the data coming from the changed line position memory 6 is the data that indicates "changed", and the data output from the changed line information memory 10 is "the line that was stored as "displayed" to "not displayed". , the line is erased once, and after the erasing is completed, a liquid crystal panel drive signal is output for writing.Also, it is data that has been changed, and any line other than 'displayed' to 'no display' A write operation is performed for the line stored as .

Note that FIG. 3 is a diagram showing the update state of erasing and writing according to the present invention. The following example shows a case where the updated character is changed from ``car°'' to ``.''. As shown in FIG. 3(B), the lines to be erased are the 5th, 9th, and 13th lines. Further, the writing line shown in FIG. 3(C) is 5.9.
There are 5 lines, 13 to J5, and the update is completed by changing these lines.

〔Effect of the invention〕

As explained above, according to the present invention, what needs to be erased and what does not need to be erased are distinguished, and what does not need to be erased is left and overwritten to be changed and updated.

Note that this improves tracking of screen changes when displaying a video signal on a liquid crystal panel, and also reduces the number of noises that occur during erasing, eliminating unnatural updates. This effect is particularly noticeable on screens where the number of characters displayed on the screen is constantly increasing.

[Brief explanation of the drawing]

1 is a diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a diagram illustrating the processing procedure of an embodiment of the present invention, FIG. 3 is a diagram illustrating the screen update state of the present invention, and FIG. FIG. 5 is a diagram showing the configuration of a conventional embodiment, FIG. 5 is a diagram showing a processing procedure of a conventional embodiment, and FIG. 6 is a diagram showing a conventional screen update state. In the figure, 1 is a data converter, 2 is a memory, 3 is an address generator, 4 is a first data comparator, 5 is a first change line monitoring circuit, 6 is a change line position memory, 7 is a liquid crystal panel drive 8 is a second data comparator; 9 is a second changed line monitoring circuit; and 10 is a changed line information memory.

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 data stored in the memory (2) are In a device that updates the screen by comparing data delayed by one frame from the data, the output of the data converter (1) and the output of the memory (2) are compared, and changes are made for each dot unit. A first data comparator (4) that compares whether it is present or not, and a timing signal output from the comparison output of the first data comparator (4) and the address generator (3). input to the changed line monitoring circuit (5) to monitor whether there is a change in line units for each field,
A changed line position memory (6) that stores the monitoring results compares the output of the data converter (1) with the output of the memory (2), and determines the content of data changes in dot units for each field. a second data comparator (8) that monitors whether there is a change from 'display present to no display' or a change other than 'display present to no display'; and the second data comparator (8); 8) and the timing signal output from the address generating section (3), a second changed line monitoring circuit (9) determines whether or not the changed data needs to be erased line by line. A changed line information memory (10) for monitoring and storing the monitored results is provided, and outputs of both the changed line position memory (6) and the changed line information memory (10) are sent to the liquid crystal panel drive control unit (
7), and the screen is updated by selecting either writing only or data erasing and writing.