JPH06175105A - Display control device - Google Patents

Abstract

PURPOSE:To easily adjust a driving condition while observing the screen even when partial rewriting is executed. CONSTITUTION:By supplying an image information signal and a scanning signal in accordance with the set driving condition are supplied to a display element 10 whose proper driving condition changes depending upon temperature, the display element 10 is controlled for driving. This device is provided with a detecting means detecting the change of image information corresponding to the image information signal, a partial rewriting means 144 for preferentially scanning and rewriting the changed part when the change of the image information is detected, a means 144 for periodically scanning and refreshing a whole screen of the display element, a means for changing and adjusting the set driving condition, a means for thus detecting the change of the driving condition and a means for transiently interrupting the partial rewriting and forcibly changing over to drive the whole screen refreshing means 144 in the meantime when the detecting means detects the change of the driving condition and the partial rewriting means 144 executes partial rewriting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display control device for driving a display element such as a liquid crystal display element, and more particularly, when an appropriate driving condition of the display element greatly changes depending on temperature. The present invention relates to a display control device capable of performing preferable display control by performing temperature compensation of driving conditions.

[0002]

2. Description of the Related Art Ferroelectric liquid crystal elements have a great feature in controlling display. One is that the proper driving condition has a large temperature characteristic, that is, the proper driving condition greatly changes depending on the temperature, and thus the temperature characteristic must be compensated (special feature). (See Japanese Unexamined Patent Publication No. 63-243923). In order to perform temperature compensation, the driving condition adjusting means can be set so that the user can adjust it so that an appropriate driving condition can be selected and the display state can be controlled.

The other is that the ferroelectric liquid crystal has a memory property, that is, the image information once written is retained (memory) even if a voltage above a threshold value is not periodically applied. Taking advantage of this feature, partial rewriting in which a rewriting signal is preferentially applied only to a portion where rewriting has been partially performed is possible (Japanese Patent Laid-Open No. 140198/1989).
(See Japanese Patent Publication).

[0004]

However, in the case of the control method in which the partial rewriting and the adjustment of the driving conditions by the user coexist, since the driving waveform above the threshold value is applied only to a certain specific portion, that portion is driven. The conditions can be adjusted by the user while looking at the screen, but it is difficult to find the optimum driving condition for the entire screen because it is not possible to judge whether the driving margin of the parts other than the partial rewriting part is appropriate. There is a problem.

In view of the problems of the prior art, it is an object of the present invention to make it possible to easily adjust the driving conditions while observing the screen even when partial rewriting is being performed.

[0006]

In order to achieve this object, a display control device of the present invention is provided with image information according to a driving condition set for a display element in which an appropriate driving condition changes depending on temperature. A display control device that supplies a signal and a scanning signal to drive and control a display element to display an image, a means for detecting a change in image information corresponding to the image information signal, and image information by the means. When it is detected that the change has been made, the partial rewriting means that preferentially scans and rewrites the portion, means that periodically scans the entire screen of the display element to refresh the entire surface, and the set driving conditions are changed. Adjustment means, means for detecting that the driving condition has been changed by this means, and when the detecting means detects the change of the driving condition, the partial rewriting means performs partial rewriting. When you are Tsu is and means for switching the drive between them forcibly the entire refresh means temporarily interrupt the partial rewriting.

The display element has, for example, a substrate having an information electrode group formed thereon, a substrate having a scanning electrode group formed thereon, and a ferroelectric liquid crystal sandwiched between the pair of substrates.

[0008]

In this structure, not only while the image information is constant, but also when the driving condition is adjusted while the image information is changing and the partial rewriting is being performed,
Since the entire screen is driven for refreshing, the driving conditions can be easily adjusted while observing the entire screen.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 5 and 6 show the scanning signals S1 to S3 output to the liquid crystal element by the display control device according to the embodiment of the present invention, the information signal D, and 1 of these composite waveforms applied to the liquid crystal of the liquid crystal element. It is an explanatory view of S2-D. Scanning signal S1
~ S3 is an erase pulse EP followed by a write pulse WP
The erase pulse EP performs switching corresponding to the direction of the electric field to erase the selected line. 5 and 6 show examples of signals in the case where the erasing pulse EP of the scanning signal S2 and the information signal pulse B are switched to the dark state to perform erasing.

Then, desired writing is performed by a writing pulse WP. The write pulse WP is applied in synchronization with the information signal D, and a composite waveform WP-D of the write pulse WP and the information signal D is applied to the liquid crystal. Composite waveform W
When P-D exceeds the threshold value, switching is performed from the erased state to the other state, and when it is less than the threshold value, the erased state is held. In FIG. 5, the composite waveform WP-D
Shows a case where switching is performed (switching from a dark state to a bright state) above the threshold value, and FIG. 6 shows a case where the erased state (dark state) is held below the threshold value. In FIG. 5, the voltage peak value of the write pulse is defined as Vop, and one horizontal scanning period is defined as 1H. These voltages V
Optimal driving conditions for each temperature are set with op and time 1H as parameters, and temperature compensation is performed.

FIG. 1 shows an F for outputting the drive signals shown in FIGS.
It is a block diagram of an LC element display control circuit system. This circuit system is a FLC whose appropriate driving condition changes depending on the temperature.
An image information signal and a scanning signal according to a set driving condition are supplied to the display element 10 to drive and control the display element 10 to display an image, which corresponds to the image information signal. An image change detection unit 142 for detecting a change in image information, and when the change in the image information is detected by this, the portion is preferentially scanned and rewritten, or the entire screen of the display element is periodically scanned. The display controller 13, the scanning and information drivers 11 and 12 and the like for refreshing the entire surface, and the adjusting element 16 and the driving condition adjusting circuit 15 for changing and adjusting the driving condition.
And a digital data comparison circuit 151 for detecting that the driving condition is changed by this, and when the partial rewriting means is performing partial rewriting when it detects the change of the driving condition, the partial rewriting is performed. Full refresh / partial rewrite switching circuit 1 for temporarily suspending and forcibly switching to driving of the full refresh means during that period
44.

The display element 10 has a substrate having an information electrode group formed thereon, a substrate having a scanning electrode group formed thereon, and a ferroelectric liquid crystal sandwiched between the pair of substrates.
80 dots are displayed. The liquid crystal material used for this purpose is a mixture containing biphenyl and phenylpyrimidine as main components, and as shown below, undergoes a phase transition depending on temperature.

FIG. 4 is a graph showing optimum driving conditions of the FLC display element 10 at each temperature. As shown in this graph, by controlling the drive voltage Vop and one horizontal scanning period 1H according to the temperature, a wide range of temperatures can be dealt with.

The scanning and information drivers 11 and 12 are included in the display controller 13 and are included in the logic controller 1.
The FLC display element 10 is driven by applying a voltage to each of the scan electrode group and the information electrode group based on each drive voltage generated by the drive voltage generation circuit 131 under the control of 32. Then, under the optimum conditions described above, the FLC display element 1
In order to drive 0, a signal indicating the driving condition is output to the logic control unit 132 via the driving condition adjusting circuit 15 which receives the output signal from the adjusting element 16 and determines the driving condition, and the scanning and information driver is based on the signal. 11 and 1
2 is controlled.

FIG. 2 is a block diagram showing this in more detail. As shown in FIG.
The OM has a drive condition table in which the drive conditions 1H and Vop in FIG. 4 are associated with each other. Adjusting element 16
Has a variable resistance volume, and a voltage value between 0 and 5 V selected by the variable resistance volume is input to the drive condition control circuit 15. This voltage value is input to the A / D converter 152 of the drive condition control circuit 15 and digitally converted. Corresponding data 1H ° and Vop ° are selected according to the digitally converted data and output to the logic control unit 132, and finally the data IH is displayed on the FLC panel.
And Vop ° are output.

On the other hand, in order to judge whether or not the condition selected by the adjusting element 16 has changed, the digital data comparison circuit 151 uses the digital data from the A / D converter 152 at a constant cycle, for example, 5 Hz, to obtain the previous data. If the same, a partial rewrite enable signal is sent, and if there is a change, a forced full refresh signal is sent.
To 44. The forced refresh period can be set for a few seconds after the digital data is being changed or when the change is first detected.

Here, partial rewriting is performed by, for example, Japanese Patent Laid-Open No.
As shown in Japanese Patent Publication No. 1040198, the image change detecting means 142 samples the scanning address accessed from the data generating section 141 in the image memory 143 at a certain cycle, and after the sampling period ends, the logic control section 132 is instructed. The scan address and the information data corresponding to the scan address are transferred, and all or some of the sampled scan addresses are preferentially scanned on the FLC display element 10 for immediate execution. As a result, even in the case of a display having a large amount of information, it is possible to draw with a good response.

FIG. 3 is a flow chart showing the operation procedure in the comparison circuit 151. That is, when the power is turned on (step 31), the address of the drive condition table corresponding to the digital signal D ₀ output by the AD converter 152 is read (step S32), and the data is stored in the memory B (step S32). S33). Next, the same reading is performed (step S34), and the data is stored in the memory A (step S35). Then, the contents of the memory A and the contents of the memory B are compared (step S
36), if they are the same, a partial rewrite permission signal is output to the full refresh / partial rewrite switching circuit 144, the process returns to step S34, and the next read is performed. If they are different, the contents of the memory A are transferred to the memory B, the full-frame refresh compulsory signal is output to the full-frame refresh / partial rewrite switching circuit 144, the process returns to step S34, and the next read is performed.

[0019]

As described above, conventionally, if partial rewriting was performed during the adjustment of the driving conditions, it was not possible to judge whether the adjustment of the driving margin of the non-scanned portion was within the proper range. According to the present invention, since the full refresh forced signal is output during the drive margin adjustment to perform the full refresh, even an inexperienced user can easily adjust the drive margin, and the whole screen is always good. Image quality can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of a FLC element display control circuit system that outputs the drive signals of FIGS. 5 and 6 according to an embodiment of the present invention.

FIG. 2 is a block diagram showing in more detail a configuration for outputting a signal indicating a driving condition to a logic control unit.

FIG. 3 is a flowchart showing an operation procedure in a comparison circuit.

FIG. 4 is a graph showing optimum driving conditions at each temperature of the FLC display element.

FIG. 5 is an explanatory diagram of a scanning signal, an information signal, and a composite waveform of these which are output to a liquid crystal element by a display control device according to an embodiment of the present invention, in the case where they are erased and further switched. is there.

FIG. 6 is an explanatory diagram of a scanning signal, an information signal, and a composite waveform of these which are output to a liquid crystal element by a display control device according to an embodiment of the present invention, in the case where they are erased and maintained. is there.

[Explanation of symbols]

S1 to S3: Scan signal, D: Information signal, S2-D: Composite waveform, EP: Erase pulse, WP: Write pulse, B: Information signal pulse, 10: FLC display element, 11: Scan driver, 12: Information driver , 13: display controller, 15: drive condition adjusting circuit, 16: adjusting element, 13
1: drive voltage generation circuit, 132: logic control unit, 14
1: data generating unit, 142: image change detecting means, 14
3: image memory, 144: full refresh / partial rewrite switching circuit, 151: digital data comparison circuit, 152:
A / D converter.

Claims (2)

[Claims] 1. A display element is driven and controlled by supplying an image information signal and a scanning signal according to a set driving condition to a display element whose proper driving condition changes depending on temperature. And a means for detecting a change in the image information corresponding to the image information signal, and when it is detected that the image information has changed, the portion is preferentially scanned. Partial rewriting means for rewriting, means for periodically scanning the entire screen of the display element to refresh the entire surface, means for changing and adjusting the set driving conditions, and detection of the change of the driving conditions thereby In the case where the partial rewriting means is performing partial rewriting when the change of the driving condition is detected by the detecting means, the partial rewriting is temporarily interrupted, and during that period, the strong rewriting is performed. And a means for switching to driving the whole surface refreshing means. 2. The display element has a substrate on which an information electrode group is formed, a substrate on which a scanning electrode group is formed, and a ferroelectric liquid crystal sandwiched between the pair of substrates. The display control device according to claim 1.