JPH0480714A - Method and device for driving liquid crystal matrix panel - Google Patents

Abstract

PURPOSE:To reduce the generation of a display irregularity by generating a B-system AC signal for two of four frames and an AC signal which is obtained by dividing the frequency of a line signal for other two frames. CONSTITUTION:The AC signal of the system (B system) which is generated by polarity inversion in a two-frame period is generated for two of four frames and the AC signal generated by dividing the frequency of the line signal is generated for other two frames. In this case, the AC signal is generated with the signal obtained by dividing the frequency of the line signal, i.e. the signal of lower frequency than the line signal, so a liquid crystal driving voltage inversion period is less than the value obtained when the line signal is used without frequency division and the driving conditions of the liquid crystal matrix are relaxed. Consequently, the display irregularity is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a time-division driving method and a driving device for a liquid crystal matrix panel, and particularly to a driving method and a driving device suitable for obtaining a high-quality display with little display unevenness. It relates to a drive device.

[Conventional technology]

A voltage averaging method is generally used as a method for time-divisionally driving a liquid crystal matrix panel, and this method involves reversing the polarity within one frame period (the time it takes to scan all the scanning lines once) and converting it to alternating current. There are two types: a method in which the polarity is reversed within two frame periods and converted to AC (hereinafter referred to as B method). For more information on these methods, see
For example, Nikkei Electronics August 16, 1980 issue 1
Discussed on pages 50-174.

FIG. 2 is an example of a configuration diagram of a general liquid crystal driving device, and FIG. 3 shows control signals and data signals for implementing time-division driving according to the B method for the liquid crystal driving device shown in FIG. FIG. 3 is a voltage waveform diagram showing an example of the voltage waveform.

In Figures 2 and 3, FLM is a frame signal that controls the scanning period of one screen, CLI is a line signal that controls the scanning period of one line of scanning electrodes, D is a data signal that represents display content, and CL2 is a scanning electrode A shift signal for synchronizing one line of data signal into the shift register of the signal side drive circuit 7. M controls polarity reversal to alternating the liquid crystal drive voltage of each pixel of the liquid crystal matrix panel. This is a polarity inversion signal (alternating current signal). Note that the transfer format of the data signal may be either serial transfer or parallel transfer, and is not particularly limited.

In the liquid crystal matrix panel 1, a plurality of scanning electrodes and a plurality of signal electrodes intersect to form pixels, and drive voltages are output from a scanning side drive circuit 6 and a signal side drive circuit 7 to drive the liquid crystal of each pixel. The operation of the scanning side drive circuit 6 and the signal side drive circuit 7 is based on the frame signal FLM and the polarity inversion signal M.
, line signal CL1. It is controlled by the shift signal CL2 and the data signal at the timing shown in the voltage waveform diagram of FIG.

In FIG. 3, fF indicates the frame frequency of the frame signal FLM, and the polarity inversion signal M is the frame frequency of the frame signal FLM.
The polarity is reversed in synchronization with the LM, and AC is made available for two frame periods.

Further, the scanning period of each scanning electrode is controlled by a line signal CL1, and in synchronization with this line signal CLI, a driving voltage is output from the scanning side drive circuit 6 and the signal side drive circuit 7 to drive the liquid crystal of each pixel. drive At this time, the drive voltage of each signal electrode is determined by the data signal of each signal electrode latched by the signal side drive circuit 7.

Currently, as a method for time-divisionally driving a liquid crystal matrix panel, the B method shown in the examples of FIGS. 2 and 3 described above is mainly used in order to reduce the burden on the drive circuit. However, in this B-type driving method, the frequency component of the liquid crystal driving voltage at a certain pixel varies depending on the display content of the liquid crystal matrix panel.

A display example is shown in FIG. For example, in FIG. 4, signal electrodes 1, 2, 3 . ...and scanning electrodes 1, 2゜3, ...
(2, 11) on the same scanning electrode 11 when a driving voltage is applied to display several patterns in the scanning direction.
(7,11), (12,11), (17,11),
(22°11) Each liquid crystal drive voltage V LC in the pixel
I + V LC2+VLC31VLC'4+ Vt,
The voltage waveform of cs is shown in FIG.

Note that the pixels indicated by (x, y) above represent the pixels located at the positions where X is the number of the signal electrode and y is the number of the scan electrode in FIG. 4, respectively.

In FIG. 5, VLCI indicates that all pixels on the same signal electrode are in a non-selected state, VLC2 indicates that all pixels on the same signal electrode are selected, and VLC3+VLC4+VL
C5 shows the voltage waveform of the liquid crystal drive voltage when the pixels on the same signal electrode display a selected state and a non-selected state at intervals of 4 pixels, 2 pixels, and 1 pixel, respectively, in the scanning direction.

Voltage waveform in Figure 5 VLCI r VLC2t VLC3
+ As can be seen from VLC4+vLc5, the more frequently the state changes from "selected" to "non-selected" or from "non-selected" to "selected" in the display in the scanning direction of the liquid crystal matrix panel, the frequency component of the liquid crystal drive voltage increases. becomes higher.

In addition, the threshold voltage Vth of the liquid crystal drive circuit voltage-transmittance characteristic (Fig. 7) of the liquid crystal of each pixel of the liquid crystal matrix panel generally changes depending on the frequency component, as shown in the characteristics of Fig. 6. It has the property of

Therefore, even if the pixels have the same display data, a phenomenon (display unevenness) occurs in which the transmittance of a certain pixel varies depending on the display content of the liquid crystal matrix panel.

As a method for solving this problem, there is a method of inverting the polarity of the polarity inversion signal M in a period shorter than the frame period TF.

FIG. 8 is a diagram showing voltage waveforms when the period of polarity inversion of the polarity inversion signal is changed for the liquid crystal drive voltage of the (12, 11) pixel in FIG. 4. In FIG. 8, VLCa
When the polarity of the polarity inversion signal is inverted in one frame period,
VLCb+ VLCct VLCd outputs each polarity inversion signal Mb, so that the polarity inversion signal is inverted in a period that is 6 times, 4 times, and 3 times the period TCLI of the line signal CLI, respectively.
It shows the voltage waveform of the liquid crystal drive voltage when the period of polarity reversal of Mo and Md is changed.

Voltage waveform VLCa+ VLCb+ VLCct in Figure 8
As can be seen from the voltage waveform of VLCd, except for VLCc, where the data inversion period of the data signal and the polarity inversion period of the polarity inversion signal match, the shorter the polarity inversion period of the polarity inversion signal, the lower the frequency of the liquid crystal drive voltage. Ingredients become high.

Using this idea, a conventional technique for shortening the period of polarity reversal of a polarity reversal signal and preventing the occurrence of display unevenness caused by fluctuations in the threshold voltage, especially on the low frequency side, is disclosed in Japanese Patent Laid-Open No. 61-109098. can be mentioned.

However, although this conventional technique can reduce fluctuations in the frequency component of the liquid crystal drive voltage on the low frequency side, it is less effective against wide range fluctuations in frequency components associated with display content. Also,
In the future, if high-time-division driving of the - layer is advanced, this conventional technique will have a problem in that display unevenness due to fluctuations in the frequency fluctuation component of the liquid crystal drive voltage will become significant.

Therefore, in the conventional technology described in Japanese Patent Application Laid-Open No. 61-73928, alternating current is changed every four frames, two of the four frames use the B system alternating signal, and the remaining two frames are line-transformed. We are trying to convert it into alternating current by using a signal whose polarity is reversed.

[Problem to be solved by the invention]

If the above-mentioned conventional technology described in JP-A-61-73928 is adopted, display unevenness caused by fluctuations in the liquid crystal drive voltage reversal period can theoretically be significantly reduced. With explanation.

6). However, if AC conversion is performed intensively in synchronization with two frame line signals out of four frames, the average number of polarity inversions per frame in the four frames becomes extremely high, and the driving conditions of the liquid crystal matrix panel This causes a problem in that new display unevenness due to other causes becomes more likely to occur.

An object of the present invention is to provide a driving method and a driving device for a liquid crystal matrix panel, which suppress fluctuations in the liquid crystal driving voltage reversal period and reduce display unevenness caused by the fluctuations without making the driving conditions of the liquid crystal matrix panel strict. It's about doing.

[Means to solve the problem]

The above object is achieved by using B-scheme AC signals for two of the four frames and using AC signals obtained by frequency-dividing the line signal for the other two frames. (Inventions of Claims 1 and 4) The above object is also achieved by dividing one frame into a plurality of parts and converting two of the four frames into B-scheme AC signals,
The other two frames can also be achieved by using a line signal whose polarity is inverted as an alternating signal and selecting each alternating signal independently for each divided period. (Inventions of Claims 2 and 5) The above object is also achieved by dividing one frame into a plurality of parts and converting two of the four frames into B-scheme alternating signals;
The other two frames can also be achieved by converting the frequency-divided line signal into an alternating current signal. (Inventions of Claims 3 and 6) [Operation] Since two of the four frames are converted into alternating current with a frequency-divided line signal, that is, a signal with a lower frequency than the line signal, the liquid crystal drive voltage inversion period is , is lower than the value when a line signal without frequency division is used, the driving conditions of the liquid crystal matrix panel are relaxed, and display unevenness is also reduced.

By dividing one frame into multiple parts and converting the line signals into AC signals for two of them, the AC conversion signals will not be concentrated in one frame, so the driving conditions of the liquid crystal matrix panel can be made more gentle. become, again,
Display unevenness is also reduced.

Of course, in this case as well, the line signal may be converted into alternating current using a frequency-divided signal.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

The embodiments of the present invention are directed to liquid crystal matrix panels that are often used as display devices for data processing devices such as personal computers and word processors, and liquid crystal matrix panels that are used as light valves for projectors. A simulation program was executed to find out what happens to the liquid crystal drive voltage inversion period when the liquid crystal matrix panel is driven by the driving method described in the claims, and the results will be explained.

As mentioned above, the frequency component of the liquid crystal drive voltage varies depending on the display content of the liquid crystal matrix panel, that is, from "selection" to "non-selection" or "non-selection" in the display of the pixel group on the same signal electrode in the scanning direction. It changes depending on the frequency of state change to "select" and the polarity inversion period of the rollover inversion signal M.

FIG. 9 is a flowchart of a simulation program for determining the frequency component of the liquid crystal drive voltage that changes depending on the display content of the liquid crystal matrix panel and the period of polarity inversion of the polarity inversion signal.

The fluctuation in the frequency component of the liquid crystal drive voltage in each pixel of the liquid crystal matrix panel is determined by the number of polarity reversals of the liquid crystal drive voltage (
This can be thought of as a change in the number of counts.

Regarding the liquid crystal drive device shown in Figure 2, the number of time divisions is Qine.
rmax (=Ny), and the inversion period of the polarity inversion signal M is set to xax, and the drive is assumed to be performed using a control signal as shown in the voltage waveform of FIG.

Also, focusing on a certain signal electrode, the period of change of the data signal to the pixel group on the same signal electrode (change in state from "selected" to "non-selected" or from "non-selected" to "selected") is determined by cj
As max, the polarity cjsign of the data signal and the polarity m-m-5i of the polarity inversion signal M are shown as "1" when they are positive, and as 11111 when they are negative.

The polarity of the liquid crystal drive voltage of each pixel is the above 141 I+ and -
The product of the polarity of the data signal indicated by "1" and the polarity of the polarity inversion signal M is obtained by calculation, and becomes "1" when it is positive and 11111 when it is negative.

In the flowchart of FIG. 9, first, select an arbitrary pixel (scan number g, 1ne-count) on a certain signal electrode.
The polarity of the polarity inversion signal M is multiplied by the polarity of the data signal, cjsign, to find out the polarity of the liquid crystal drive voltage.

Next, for the target signal electrode, the polarity vjLc of the liquid crystal drive voltage during the current scan is compared with the polarity v-Qc-old of the liquid crystal drive voltage during the previous scan. If these values are equal, it is determined that the polarity is the same, and if they are different, it is determined that the polarity has been reversed, and the number of times the polarity has been reversed is counted.

Then, according to the conditions of d-wax and irises-wax, while changing each polarity d-sign and m-m-5i, the polarity of the liquid crystal drive voltage of the pixels of scan number 111ine count=1 to NY was changed in the same way as above. and count the number of times the polarity has reversed. The count obtained by this is the number of polarity inversions of the liquid crystal drive voltage in one frame period.

Note that the unit of the period of polarity inversion of the polarity inversion signal M and the period of the data signal is one period (Tct+) of the line signal CLI.
It is.

Using the program created from the flowchart in Figure 9, the number of time divisions mine-wax = N y = 480
Under the conditions of (B method), the inversion period of the data signal cj+a
FIG. 10 shows simulation results of the number of polarity inversions of the liquid crystal drive voltage for ax=1 to 480.

Note that, in reality, the polarity of the liquid crystal drive voltage of each pixel is reversed in two frame periods to convert it into an alternating current. Therefore, by setting the initial polarity of the polarity reversal count sign in the flowchart of FIG. 9 to positive (1") and negative ("-1"), we simulated the number of polarity reversals of the liquid crystal drive voltage in two frame periods. The number of polarity reversals NLCD of the liquid crystal drive voltage per one frame period was determined.

Also, before executing the first frame in the program created from the flowchart shown in Figure 9, v3cmof
Ld was set to the polarity of the liquid crystal drive voltage for the first line of the first frame. This is the polarity v-Etc of the liquid crystal drive voltage of the first line of the first frame in the program of the flowchart shown in FIG. 9, and the undefined vIlc.

This is to avoid counting changes in polarity reversal of the liquid crystal drive voltage due to polarity comparison with fLd.

Furthermore, at the end of the program of the second frame, the polarity of the liquid crystal drive voltage of the 480th line of the second frame is changed to Vic-o.
It is determined whether the polarity of the liquid crystal drive voltage vQc of the first line of the third frame (first frame) is reversed.

As shown in FIG. 10, in the case of 33ax==480 (B method), it can be seen that the number of polarity inversions of the liquid crystal drive voltage per frame period increases as d)ax is smaller.

This change in the number of polarity inversions of the liquid crystal drive voltage corresponds to a frequency component of the liquid crystal drive voltage that changes depending on the display content of the liquid crystal matrix panel and the period of polarity inversion, and this is the cause of display unevenness.

FIG. 11 shows an embodiment of the polarity inversion signal generation circuit of the liquid crystal driving device in this embodiment.

The circuit shown in FIG. 11 divides the FLM signal and CLI signal by counters 17 and 18,
, and other logic circuits 20, 21, 22, and 23, the polarity inversion signal M+2 is synthesized. c.
The o-fold signal is a signal obtained by dividing the frequency of the CLI signal by n.

FIG. 12 shows a time chart of the polarity inversion signal M + 2, the FLM signal, the CLI signal, the a pressure waveforms cn of the counters 17 and 18, and F3t F4 obtained by the circuit of FIG. 11.

In FIG. 12, the polarity inversion signal M, 2 is unipolarity (positive polarity) for one frame period of the B method in a certain arbitrary A frame, and CL in the continuation < (A+1) frame.
n' TCL in synchronization with the Cn signal obtained by dividing the I signal by n.
Reversal of polarity at + intervals, (A+2)'7 lems.

(A + 3) frame is A frame, (A + 1)
The frames are synthesized to reverse the polarity of the frames.

The polarity inversion signals M and 2 change the period of polarity inversion every frame period, and in a liquid crystal driving device as shown in FIG. Then perform one exchange and repeat this.

FIGS. 13(a) and 13(b) are flowcharts of a simulation program for confirming the effects of the embodiments shown in FIGS. 11 and 12. This simulation assumes the liquid crystal drive device shown in Fig. 2, and the number of time divisions Qins,
, +aax = N y = 480.

First, the inversion period d-wax of the data signal is input.

The data count is initialized to O at the beginning of the A frame. In addition, each input data (m-wax, d-c
ount.

m-count, d-sign, m sign), and execute the program shown in FIG. 9, indicated by SUB in the figure, to find the count of the number of polarity inversions of frames A to (A+3). This count value is 1/4
Then, calculate the number of polarity reversals NLCD per frame.

In the A-frame flowchart, before executing the program (SUB) of the flowchart shown in FIG. 9, v-Me-oAd was set to the polarity of the liquid crystal driver voltage of the first line of the A-frame. This is because the polarity V-1c of the liquid crystal drive voltage on the first line of the A frame and the undefined v-Q, c-
This is to avoid counting changes in polarity reversal of the liquid crystal drive voltage due to polarity comparison with aid. Finally, the polarity v-Q of the liquid crystal drive voltage on the 480th line of the (A+3) frame, ciofld, and (A+4
) The polarity v-Qc of the liquid crystal drive voltage of the first line of the frame (corresponding to the A frame) is compared. This allows the number of polarity inversions for four frames to be accurately determined.

Using the program created from the flowchart in Figure 13, the polarity reversal period n'' TCLI of the (A+1) frame and (A13) frame in Figure 12 is set to n=1°2.4.
, and set the inversion period J3ax of the data signal to 1 to 480.
The number of polarity reversals of the liquid crystal drive voltage per frame period when simulating A to (A+3) frames by changing the NLCD to MI in FIG. 14(a),
Shown in MZ and M4. For comparison, the simulation results for n=480 (B method, that is, when the number of divisions is n=480, all one frame has positive or reverse polarity) are also shown in b. Here, M corresponds to alternating current according to the prior art (Japanese Unexamined Patent Publication No. 61-73928).

In FIG. 14(a), the vertical axis represents the average number of polarity reversals NLCD of the liquid crystal drive voltage per frame period.

As can be seen from FIG. 14(a), except for MI (n=1) and b (B method), the inversion period of the data signal +:jma
As x increases, the number of polarity reversals per frame of the liquid crystal drive voltage N LCD decreases while oscillating.

Also, MI does not depend on d-max, NLCI) is constant, and b (B method) is d as explained in FIG.
■Decreases as ax increases.

From the simulation results shown in Figure 14(a), in order to clarify the relationship between display content and fluctuations in the frequency component of the liquid crystal drive voltage, the value of NLCD (Cmax = 480), which is the lowest value from NLCD of each characteristic, is Then, the fluctuation difference in the number of polarity reversals is expressed as ΔNLCD 6 Also, in the characteristics of MZ and M4, the larger value among the oscillating values is shown in Figure 14C.
The curves were connected by the dashed-dotted line and the dashed-double-dotted line shown in a), and the value obtained by subtracting this curve by the lowest NLCD value (d−■ax=480) was expressed as the fluctuation difference ΔNLCD. The characteristics of the inversion period d-vaax and the fluctuation difference ΔI'Jt, co of the above data signal are shown in FIG. 14(b).

As can be seen from the change in ΔLCD with respect to d-wax in FIG. 14(b), compared to the change in b (B method), the 11th
The polarity inversion signal Ml according to the embodiment of FIG.

The smaller the change in the characteristics of MZ and M4, and the smaller n is,
It can be seen that the change is small. cjIlax is the fineness of the display content, ΔN LCD is the fluctuation of the frequency component of the liquid crystal drive voltage, n is the (A+1) frame in Figure 12, (A+3)
Since the polarity reversal period n of the frame corresponds to the frequency division ratio n of TCLI, the embodiment using the circuit shown in Fig. 11 and the driving method shown in Fig. 12 is effective in reducing the frequency component of the liquid crystal drive voltage associated with one display content. It can be seen that there is.Furthermore, TC
It can be seen that the smaller the frequency division ratio n of LI, the greater the reduction effect.

However, if n=1, as shown in Figure 14(a),
The number of polarity inversions NLCD per frame is 240. Converting to alternating current at such a high frequency places a burden on the load, and the waveform of the voltage across the liquid crystal becomes dull, making the effective voltage non-uniform, which causes new display unevenness. Therefore, as a countermeasure against display unevenness due to fluctuations in the liquid crystal drive voltage inversion period, it is best to set n=1, but this cannot be practically adopted.

In this way, according to the embodiment of the circuit shown in FIG. 11 and the driving method shown in FIG. 12, it is possible to suppress fluctuations in the frequency component of the liquid crystal drive voltage due to the display contents of the liquid crystal matrix panel, and it is possible to suppress display unevenness. It also becomes easier to drive the load while reducing generation.

FIG. 15 is a configuration diagram of a polarity inversion signal generation circuit according to another embodiment of the liquid crystal driving device of the present invention.

The circuit shown in FIG. 15 divides the FLM signal and CLI signal by counters 70, 8, D-type flip-flop 9, other logic 10, 11, 12, 13, 14, 15,
16, the polarity inversion signal MH is synthesized. The Co signal is a signal obtained by frequency-dividing the CLI signal by n (excluding n=1 for the same reason as above).

FIG. 16 shows the polarity inversion signal M obtained by the circuit of FIG. 15, the FLM signal, the CLI signal, and the counter 70.
, 8 is a time chart of output voltage waveforms On, Fl, and F2.

In FIG. 16, the Mth polarity inversion signal is an arbitrary A
Frame and continuation < In the (A+1) frame, the polarity of the B method is reversed, and in the (A+2) frame, n is synchronized with the C1 signal.
' The polarity is inverted at TCL1 intervals, and the (A+3) frame is synthesized so that the polarity is inverted to the opposite polarity of the (A+2) frame.

The polarity inversion signal M I H changes the period of polarity inversion every two frame periods, and in a liquid crystal display device as shown in FIG. Perform one exchange and repeat this.

For the M-th polarity inversion signal as well, if the number of polarity inversions of the liquid crystal drive voltage is simulated in the same manner as in FIG. 13, it will show the same characteristics as in FIGS. 14(a) and (b).

Therefore, the same effects as the embodiment of the circuit shown in FIG. 11 and the driving method shown in FIG. 12 can be obtained, and display unevenness is reduced.

The circuits shown in Figures 11 and 15 above and Figures 12 and 16
According to the embodiment of the driving method shown in the figure, in the liquid crystal driving device, by changing the period of polarity reversal of the polarity reversal signal every one frame period or every plural frame period, the liquid crystal driving voltage can be adjusted according to the display contents of the liquid crystal matrix panel. It is possible to suppress fluctuations in frequency components, and the occurrence of display unevenness can be reduced.

The circuits shown in FIGS. 11 and 15 and FIG. 12 above.

The period of polarity reversal of the polarity reversal signal of the liquid crystal driving device according to the embodiment of the driving method shown in FIG. 16 is not particularly limited to the period of the above embodiment in each frame. Further, the order of each frame from A to (A+3) is not particularly limited, as long as it is converted into an alternating current over a plurality of frames. C which frequency-divided the CLI signal
The value of the frequency division ratio n of the n signal is not particularly limited to the values discussed in FIGS. 14(a) and 14(b). The synchronization and periodicity with the CLI signal and FLM signal are also not particularly limited. Further, the period during which the polarity inversion signal has a constant polarity inversion period is not particularly limited to the period of the above embodiment.

FIG. 17 shows a configuration diagram of yet another polarity inversion signal generation circuit in the liquid crystal driving device of the present invention.

The circuit shown in FIG. 17 divides the FLM signal and CLI signal by counters 24, 25, and multivibrators 26, 25, .
Data selector 27. D-type flip-flop 28, other logic circuits 29.30.31.32.33°34
The timing is determined and the polarity inverted signal M13 is synthesized. The Cn signal is a signal obtained by dividing the frequency of the CLI signal by n.

Figure 18 shows a time chart of the polarity inversion signal M13, FLM signal, CLI signal, output voltage waveform C1r F5+ F7 of counter 24.25, and output voltage waveform F6 of the multivibrator obtained by the circuit of Figure 17.
Shown in a) and (b).

In an arbitrary A frame, the polarity inversion signal M13 in FIGS.
The signals are synthesized so as to synchronize with the Cn signal and change the polarity to alternating current at intervals of n'' TCLI.Continued (A+1
) frame performs polarity inversion of the opposite polarity of the A frame. In the (A+2) frame, the polarity is inverted at n'' TCLI intervals in synchronization with the Cn signal in period d, and unipolar alternating current is performed in period e.Then, (A+3
) frame, performs polarity inversion of the opposite polarity of the (A+2) frame.

The polarity inversion signal M+3 performs polarity inversion at an independent arbitrary period in a plurality of periods divided into two in this embodiment in each frame, and if we focus on one pixel, the polarity is inverted in two frames. The period of polarity reversal for each period is changed. Therefore.

In the liquid crystal driving device as shown in FIG. 2, alternating current is performed over four frame periods of frames A to (A+3), and this is repeated.

For the above polarity inversion signal M+3, if the number of polarity inversions of the liquid crystal drive voltage is simulated for each pixel in the same manner as in FIG. 13, the result will be as shown in FIG. 14(a).

It shows the same characteristics as (b). Therefore, the same effects as the embodiment of the circuit shown in FIG. 11 and the driving method shown in FIG. 12 can be obtained, and display unevenness is reduced.

In this embodiment, n may be set to 1.

This is because one frame is divided into multiple periods, and for each divided period it is selected whether to use the B method signal or the line signal as the AC conversion signal. Therefore, the AC conversion using the line signal is performed during the entire frame period. This is because the above-mentioned problem does not occur because the high-frequency signal does not remain in alternating current for a long period of time. It goes without saying that a signal obtained by dividing the line signal may also be used.

FIG. 19 shows an embodiment of yet another polarity inversion signal generation circuit in the liquid crystal driving device of the present invention.

The circuit shown in FIG. 19 divides the FLM signal and CLI signal by counters 35, 36, multivibrators 37,
The data selector 38, the D-type flip-flop 39, and other logic circuits 40, 41, 42, 43° 44 take the timing and synthesize the polarity inversion signal M14.
The Cn signal is a signal obtained by dividing the frequency of the CLI signal by n.

A polarity inversion signal M14 obtained by the circuit of FIG. 19,
The time chart of the FLM signal, CLI signal, output voltage waveform cn of counter 35 and 36, F8t Flo, and output voltage waveform F9 of multivibrator 37 is shown in Figure 1 (
aL Shown in (b).

In an arbitrary A frame, the polarity inversion signal M in FIGS.
In the period, the signals are synthesized so that alternating current with polarity inversion is performed at intervals of n'' TCL1 in synchronization with the Cn signal.

In the (A+1) frame, the polarity is changed to alternating current at n'' TCLI intervals in synchronization with the C1 signal in the f period, and one-polar alternating current is performed in the g period.Furthermore, The (A+2) frame and (A+3) frame are synthesized so that the polarity of the A frame and (A+1) frame is reversed.

The polarity inversion signal M14 performs polarity inversion at an arbitrary independent period in two periods within each frame, and if we focus on one pixel, each period is divided into two periods in each frame. The period of polarity reversal is changed. Therefore, in the liquid crystal driving device as shown in FIG.
) The alternating current is carried out over a period of four frames,
Repeat this.

For the polarity inversion signal M, if the number of polarity inversions of the liquid crystal drive voltage is simulated for each pixel in the same manner as in FIG. 13, the result will be as shown in FIG. 14(a).

It shows the same characteristics as (b). Therefore, the same effects as the embodiment of the circuit shown in FIG. 11 and the driving method shown in FIG. 12 can be obtained, and display unevenness is reduced. Incidentally, in this embodiment as well, no problem occurs even if n=1 as in the previous embodiment.

As shown in the circuits shown in FIGS. 17 and 19 and the driving device method shown in FIGS. The polarity is reversed at an independent arbitrary period, and the period of polarity reversal for each period is changed to perform alternating current over a plurality of frame periods.

Thereby, it is possible to suppress fluctuations in the frequency component of the liquid crystal drive voltage depending on the display contents of the liquid crystal matrix panel, and it is possible to reduce the occurrence of display unevenness. Furthermore, in the circuits shown in FIGS. 17 and 19 and the driving method shown in FIGS. 18 and 1, the polarity inversion signal is divided into two or more periods within each frame, and each period is 1, 17, 18, etc. can also be achieved by having a means for performing polarity reversal at an arbitrary period, and changing the polarity reversal period to change the polarity to AC over a plurality of frame periods. 19th
Similar to the embodiment shown in the figure, it is possible to suppress fluctuations in the frequency component of the liquid crystal drive voltage depending on the display contents of the liquid crystal matrix panel, thereby reducing the occurrence of display unevenness.

The circuits shown in FIGS. 17 and 19 and FIG. 18 above.

In the embodiment of the driving method shown in FIG. 1, the period of polarity inversion having different periods within each frame is not particularly limited. Further, the period of polarity inversion of each of the polarity inversion signals is not particularly limited to that of the above embodiment, and the FLM signal and the CL
The synchronization and periodicity of the I signal with the frequency-divided signal C1 are also not particularly limited.

Note that the polarity inversion signal generation circuit in the liquid crystal driving device of the present invention is not particularly limited to the configurations of the embodiments shown in FIGS. 11, 15, 17, and 19, and the polarity inversion signal generation circuit obtained from each circuit Signal M 11. M + 2, M 13, M
Any circuit that can obtain a polarity inversion signal similar to No. 14 may be used.

〔Effect of the invention〕

According to the present invention, it is possible to suppress fluctuations in the frequency component of the liquid crystal drive voltage due to changes in the display contents of the liquid crystal matrix panel, and it is possible to reduce the occurrence of display unevenness.

[Brief explanation of drawings]

1(a) and 1(b) are voltage waveform diagrams of a polarity inversion signal of a liquid crystal driving device according to an embodiment of the present invention, FIG. 2 is a diagram showing an example of a general liquid crystal driving device, and FIG. 3 is a diagram showing an example of a general liquid crystal driving device. is a time chart of control signals and data signals of time-division drive using B method,
Fig. 4 is an explanatory diagram of a liquid crystal display, Fig. 5 is a time chart showing the waveform of the liquid crystal drive voltage of an arbitrary pixel in the display example of Fig. 4, and Fig. 6 is a threshold voltage with the characteristics shown in Fig. 7. Figure 7 is the liquid crystal drive voltage-transmittance characteristic diagram of the liquid crystal matrix panel, Figure 8 is the (12, 11) of Figure 4.
Voltage waveform diagram when changing the period of polarity reversal of the polarity reversal signal regarding the liquid crystal drive voltage of the pixel. Figure 9 shows the polarity of the liquid crystal drive voltage that changes depending on the display contents of the liquid crystal matrix panel and the period of polarity reversal of the polarity reversal signal. A flowchart of a simulation program for determining the number of reversals,
FIG. 1O is a graph showing the results of a simulation of the variation in the number of polarity inversions of the liquid crystal drive voltage with respect to the period of the data signal of the polarity inversion signal of the B method, and FIG. 11 is the polarity inversion of the liquid crystal drive device according to an embodiment of the present invention. Signal generation circuit diagram, 12th
The figure is a voltage waveform diagram of the polarity inversion signal and other signals generated by the circuit in Figure 11, and Figures 13 (a) and (b) are
A flowchart of a simulation program for confirming the effects of the embodiments shown in FIGS. 1 and 12, and FIGS. 14(a) and 14(b) are graphs showing the results of the simulations shown in FIGS. 13(a) and (b). FIG. 15 is a polarity inversion signal generation circuit diagram of a liquid crystal driving device in another embodiment of the present invention, FIG. 16 is a voltage waveform diagram of the polarity inversion signal and other signals output from the circuit shown in FIG. 15, and FIG. 17 18(a) and 18(b) are voltage waveforms of the polarity inversion signal and other signals output from the circuit of FIG. 17, respectively. 19 is a diagram of a polarity inversion signal generation circuit of a liquid crystal driving device in still another embodiment of the present invention.6 1...Liquid crystal matrix panel, 2...Power supply circuit, 3
...Signal control circuit, 6...Scanning side drive circuit, 7...
・Signal side drive circuit, 70.8, 17.18.24.2
5.35.36 Counter, 26.37 Multivibrator, 9,19°28, 39 D type flip-flop, 27.38 Data selector, 13.1
4.15.20.21.31.32.33.42゜43
, 44...NOT circuit, 10.11.12.22...
・NAND circuit, 16.23.29.30.40.41
...Exclusive OR circuit, 34-...AAND circuit, FL
M・7L/-me signal, CLI...line signal, CL
2...Shift signal 1M...Polarity inversion signal, D...
Data signal, TF...frame period, f...frame frequency, TcL...line signal period, d) ax
...Period of polarity inversion of data signal, m-raax...
- Period of polarity inversion of polarity inversion signal, count... Number of times of polarity inversion of liquid crystal drive voltage, Mll, M+2. M+
3. M+4...Example of polarity inversion signal of the liquid crystal display device of the present invention, Cn...CLI frequency division signal, n...CLI
Frequency division ratio, N LCD...Number of polarity reversals of the liquid crystal drive voltage per frame. Representative Patent Attorney Tadashi Akimoto Actual Diagram FLM --- Framing amount M + 4 --- One Bag Sex Anti-Soft Fa ----36aQ+5fflQF9------
37 /1Q21 output η F1. ----- 36 020 soil force CLI---
- Life No. 41 TF-----Room period f, g--Ichidousei Mekan's side period 7M2----Z's period TF-7M2-----G's period Cn-----CLI's # Shuai issue n ---- CLI's KeM ratio TCL +----CL l's shoulder period Fig. 1 (b) FLM----7L Hirodan U MI4----Ichisujirei d1 No. Fa ~---36 Q+s output D Fs---37 021 output f, Q---uniform reversal separation period TMz---f period TF-7M2----9 period Cn ---- CLI's M signal TF ----7 Rem A certain month's number 1 Electric bamboo FLY-11 Frame Ai meeting number CL l -m- Live signal CL 2 --- Shift No. 41 M=--Flashing raw anti-personal signal D--Tie number ■1~v6~--Bias voltage for cryo-crystal A11 Fig. 7F--7L-Mom usage period fF- --7 Remedy Shoulder i Dakan TCLI-Raishi Shizume no Tomo No. 8 Fig. ゝ~-81 How to East the II Statue Figure FLM --- Frame signal CLI ---1 Line signal M ----One line and 1 standard signal TF ---7 frame M English TCLI --- Line pull 1/1 Vs-
-----ARt, h VH9---IFi&(/E vb----High 1st voltage 7 voltage VLC+ ---(2, If) JJlln!b&J
Eil! /LVLC2---(7, II) VLC3---(12, l l 1 VLC4---(17, l l) VLC5---(22, If) Figure 10'm'JLt plate dividing LC (Hz) Figure th Shallow Crystal N, IEtl'x-VLCD [v] th - -L9iQffL (Above formula'/)Y→'+ piece of VLc
o) No. 8rl! J FLM --- Frame A [U CLI --- Line signal TF --- Room period TCL --- Line ('1 t'tuM11F!Mu,
Mb, Mc, Md --- 1st reverse night number Vu: a,
VLcb, vLcc, Vui --- (12, If) JL
fAvb-, Zuiasumi Shaku Vs---i1L1χElectric Ji VNs-・11 selection electric fifth diagram ti,, sα-1-data (1st Ashishira r1 cycle period Gi-Gi aZ ---1 The sandy anti-signal of corporate anti-taking,
Turnover 1 Fall d-tou*t ---7 Ichita bond ii
5! To the cycle count - cCount -
--1 to Se L anti-Oune I Tomi No. 1 town low-ranking man υ und tLsll --- 1 D' Evening signal dinner Ii total s Riga -- I ship semi anti-9 battle I 1 No. 11 1y-IC---
-(#5b-cJu*0 aroma) &/eJ7 electrodynamic Ltr weak liy-1cms/j--(line-cau chu-4)
Pull JIQatTodorokiJtmotiontLt+af'L(ρa material --
--It's, Gakunden 50 political connections and transfers □ Mekian number map L*a*, m-must> Single ゛-° Quinn f1 No. C
L14 period (Te1l) Figure 11 CLI ---74 interface 17.18-m-counter 19 --- D type 9,7 floppy 20,2
l-NOT 111+ 22-----NAND fishing 23-----4f per game! OR MESUZU n -- FLM- CLI/I minute' 1 7 Ray A1 s No. second grudge transfer signal 18 Q8 Upper 18 no. L Island Ui Frame M Period - 2 Inf "No. - CLIn#JI No. CLI's #' Shoulder Ratio CLI'll 1st Period Fig. (b) Fig. (b) A4+---n Kasumi 1's Scar Characteristics of M2---nm2-call is negative M3---n = 3 alt character 1 character b---
-n = 480/l Saitn1ltW (80,000 formula) % formula %] CLI --- Fin 4 No. Cn --- CLI JrM Borrowed name FLM --- Frame signal M++ --- Monolithic beast No. F+ ---8 Q3 output F2 ---8 nQ4 output) 1 Figure 16 FLM --- Rou A signal F+ ---8 Q3 output F2 ---8 Q4 output η TF ----y frame Mmeha CLI---Fisi signal Cn---CLI's 0M8 number n----Networked TCLI----CLI's shoulder period Fig. 24.25--i Ushita 26 ---Mirror to the receiver 27--t-tactor τrector 28-D type 7, flip-flop 29.3O-JF conversion OR tile 31, 32, 33-NOT possible 34---AN D 11% CLI-m-Uishii Tomi No. Cn---CLl's minute 1 Ken I No. FLM---Frame issue M13--One-way 11 anti-East Li No. Fs---25 /) Q+s output Fs----26 Q+a output Fy----25nQ+J force Fig. 18 FLM----Lou A inertia M+:s----J叡14υ-Signal F5----257 ) Q13 output Fa -----26's QCs output F7----27's QI4 output TF -----F LA cycle d, e---Bag f! 1st turn tv minute liu aftTMI---
d v period TF-TMI ---e /1191 darkness CLI --- line special issue Cn --- CLI 11 minutes jl signal h --- one valve station ratio TcL, -CL I's 111191 18th FI! J (b) FLM---7L-Mu Receiver M13---Ichisho■i Inverted signal Fs---25 Fishing Q13 Mountains Fs---26 QCs output F7---27 Q14 output TF- ---7 sea to 1 d, e--Division period TMI of one-hinoki reversal and rotation ----d period TF-TMI ---e 0IIl CLI----24211 No. Cn---- -CLI # is the signal n ------1 frequency division ratio TCLI ---CLI Nol1 period

Claims (1)

[Claims] 1. In a time-division driving method for a liquid crystal matrix panel,
A method for driving a liquid crystal matrix panel, characterized in that two of the four frames are used as B-type alternating current signals, and the other two frames are made from signals obtained by frequency-dividing a line signal as alternating signals. 2. In the time division driving method of liquid crystal matrix panel,
One frame is divided into multiple parts, 2 of the 4 frames are used as the B method AC conversion signal, and the other 2 frames are used as the AC conversion signal, which is a line signal whose polarity is inverted, and each AC conversion signal is divided. A method for driving a liquid crystal matrix panel, characterized in that selection is made independently for each period. 3. In the time division driving method of liquid crystal matrix panel,
A liquid crystal display device characterized in that one frame is divided into a plurality of parts, two of the four frames are used as a B-system alternating current signal, and the other two frames are made into an alternating signal obtained by dividing a line signal. How to drive a matrix panel. 4. In a time-division drive device for a liquid crystal matrix panel, two of the four frames are applied to the liquid crystal matrix panel as a B-type alternating current signal, and the other two frames are a signal obtained by dividing the line signal as an alternating signal. 1. A driving device for a liquid crystal matrix panel, comprising means for applying voltage to the liquid crystal matrix panel. 5. In a time division drive device for a liquid crystal matrix panel,
One frame is divided into a plurality of parts, two of the four frames are applied to the liquid crystal matrix panel as a B-type AC converting signal, and the other two frames are line signals with polarity inverted signals being applied to each AC converting signal. 1. A driving device for a liquid crystal matrix panel, comprising means for independently applying a signal to the liquid crystal matrix panel for each divided period. 6. In a time division drive device for a liquid crystal matrix panel,
One frame is divided into a plurality of parts, and two of the four frames are applied to the liquid crystal matrix panel as a B-type alternating current signal, and the other two frames are applied to the liquid crystal matrix panel using a signal obtained by dividing the line signal as an alternating signal. A driving device for a liquid crystal matrix panel, comprising means for applying voltage to the panel. 7. A data processing device comprising a liquid crystal matrix panel and displaying data on the liquid crystal matrix panel, characterized by comprising the drive device according to any one of claims 4 to 6. 8. A projector using a liquid crystal matrix panel as a light valve, comprising the drive device according to any one of claims 4 to 6.