JPH05181433A - Driving system of display device - Google Patents

Abstract

PURPOSE:To suppress the generation of crosstalk and a decrease in contrast by executing in-row inversion of the polarity of a driving voltage, applied to liquid crystal, and making both the field to be inverted row by row, and the field not to be inverted together, coexist. CONSTITUTION:The fields T1-Tm (T field) where in-row inversion is performed in each selection period and row-by-row inversion (inversion in the polarity of operation select signal on every change in row) is not performed and the fields t1-tm (t field) where the row-by-row inversion is performed are arranged alternately. In this case, a signal when at a high potential is a signal indicating the row-by-row inversion. Consequently, P1a-P1c are equal in the frequency of variation in column electrode driving voltage in nonselection periods on the average throughout the T fields and (t) fields and the effective value in the nonselection periods is unchanged without reference to a display pattern. Further, the influence of parasitic resistance is reducible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display panel having a plurality of column electrodes and a plurality of row electrodes, a row electrode drive circuit for applying a scanning selection signal to the row electrodes, and a display data for the column electrodes. A column electrode drive circuit that applies a column electrode drive signal, a drive power supply circuit, and a control circuit.Each display pixel has an effective value of a drive voltage applied to both ends of each pixel through a selection period and a non-selection period. The present invention relates to a drive circuit of a display device that is driven in a related manner and that displays a bright and dark display state by a difference in effective value of a drive voltage applied to both ends of each pixel during the selection period.

[0002]

2. Description of the Related Art FIG. 2 is a conceptual configuration diagram of a general liquid crystal display device. A plurality of row electrodes X1, X2, ... Xm are connected to a row electrode drive circuit 203, and a plurality of column electrodes Y1, Y2.
, Yn are connected to a column electrode drive circuit 202, and the column electrode drive circuit 202 and the row electrode drive circuit 203 are connected to a control circuit 201 and a drive power supply circuit 204, respectively. Here, it is assumed that m is an even number. The display data source is included in the control circuit 201.

FIG. 3 shows the column electrode drive circuit 2 shown in FIG.
02 is a block diagram showing the row electrode drive voltage circuit 203 more specifically, and the drive power supply circuit 204 is not shown. In FIG. 3, the column electrode drive circuit 202 receives a control signal including a clock signal and display data from the control circuit 201 and stores the display data.
01 and a control signal from the control circuit 201,
A holding circuit 302 that holds the output of the memory circuit 301 for one selection period of row electrode scanning, a voltage switching circuit 303 that inverts the output of the data holding circuit 302 based on a polarity inversion signal from the control circuit 201, and the holding circuit 302. Voltage switching circuit 3
The output circuit 304 generates a column electrode drive voltage to be applied to each column electrode of the display panel 307 on the basis of the output of the display panel 307.
A scan signal generation circuit 305 which receives a control signal including a clock signal from 01 and creates a row electrode scan selection signal;
The output signal of the scanning signal generation circuit 305 and the control circuit 2
An output circuit 30 for generating a row electrode drive voltage to be applied to each row electrode of the display panel 307 according to a control signal from 01.
It is composed of 6.

FIGS. 4 (a) and 4 (b) are diagrams showing a typical setting method of voltages applied to the row electrodes and column electrodes when driving the liquid crystal display device shown in FIGS. Yes, Figure 4
(A) is a system using 6 level voltages of V1 to V6, and FIG. 4 (b) is a system using 4 level voltages of ± Vc and ± Vs. The present invention is compatible with any of the methods, but the description will be given for the case of using the method of FIG.

FIG. 5 shows more detailed driving waveforms when the driving method of FIG. 4B is adopted. In FIG. 5, the first row electrode X1 is selected during the periods T1 and t1. The periods T2 and t2 are periods for selecting the second row electrode X2, and the periods Tm and tm are similarly periods for selecting the mth row electrode Xm. If each of the periods T1 to Tm and the periods t1 to tm is defined as one field, each pixel of the first row electrode X1 and P11 to P1n have the period T1 or t within one field.
Only one period is selected, and other periods are called non-selected periods.

When the potential applied to the row electrodes during the non-selection period is defined as the reference potential (0V), + Vc is applied to the row electrode X1 and 0 to the other row electrodes during the period T1.
V is applied. In the period T2, + Vc is applied to the row electrode X2, and 0V is applied to the other row electrodes. Similarly, + V is applied to the row electrode Xm during the period Tm.
c is applied, and 0V is applied to the other row electrodes.
Moving to the next field, -Vc is applied to the row electrode X1 in the period t1, 0V is applied to the other row electrodes, and -Vc is applied to the row electrode X2 in the period t2. 0V is applied to the row electrode of, and similarly, −Vc is applied to the row electrode Xm during the period tm.
0V is applied to the other row electrodes. This method is called a field inversion method. In FIG. 5, the symbol F indicates a field inversion signal.

On the other hand, regarding the column electrodes, three column electrodes Y
Consider a, Yb, and Yc. Further, the liquid crystal is of a type that displays a bright state by a high applied voltage. The display of all pixels on the column electrode Ya is in a bright state, the display of all pixels on the column electrode Yb is in a dark state, and the display of pixels on the column electrode Yc is alternately in a bright state and a dark state. If it is performed, -Vs is applied to the column electrode Ya over the entire period of T1 to Tm, and + Vs is applied over the entire period of the period t1 to tm. + Vs is applied to the column electrode Yb for all the periods T1 to Tm, and -Vs is applied for all the periods t1 to tm. In addition, the column electrode Yc
, The periods T1, T3, ... Tm-1 and t2, t4,
...- Vs is applied to tm, and the periods T2, T4
, ... + Vs for Tm and t1, t3, ... tm-1
Is applied.

That is, the column electrode drive voltage (row electrode drive voltage) such that the absolute value of the drive voltage applied to both ends of the liquid crystal becomes | Vc + Vs | during the selection period in which a bright state is displayed on each column electrode. Is + Vc, + Vs is applied when the row electrode drive voltage is -Vc, and the absolute value of the drive voltage applied to both ends of the liquid crystal is | A column electrode drive voltage (+ Vs when the row electrode drive voltage is + Vc, −Vs when the row electrode drive voltage is −Vc) that is VC−Vs | is applied.

At this time, the pixel P1a is formed at the intersection of the first row electrode X1 and the column electrode Ya, and the pixel P1a is formed at the intersection of the first row electrode X1 and the column electrode Yb. The driving voltage applied to both ends of the pixel P1b and the pixel P1c formed at the intersection of the row electrode X1 of the first row and the column electrode Yc is as shown in FIG. The pixels P1a, P
The absolute value of the drive voltage applied to 1c is | Vs + Vs | during the selection period and | Vs | during the non-selection period, and the effective voltage over one field is the value shown in Formula 1. Then, both the pixels P1a and P1c exhibit the bright state. The absolute value of the driving voltage applied to the pixel P1b is | Vs-Vs | in the selection period and | Vs | in the non-selection period, and the effective voltage over one field is several 2. The pixel P1b has the indicated value and exhibits the dark state.

[Equation 1]

[Equation 2]

In equations 1 and 2, (Vc ± Vs) 2 / m
Is related to the selection period, and is (m-1) .Vs2
The term / m is related to the non-selection period. The larger the value of V1 / V2, the better the contrast between the bright state and the dark state. V1 / V2 is given by the equation 3, and its theoretical maximum value is given by the equation 4.

[Equation 3]

[Equation 4]

The above description is for an ideal state only. In reality, since distortion occurs in each waveform, the pixels P1a and P1
1c does not have the same display state. This phenomenon is often explained by the waveform diagram shown in FIG. That is, assuming that the waveform of each part is distorted each time the state changes, the effective value of the drive voltage applied to both ends of each of the pixels P1a and P1c is the column electrode drive voltage in the non-selected period. Since the pixels P1a and P1c do not have the same display state because they have different values depending on the difference in the number of state changes, the crosstalk is one of the causes.
That is, in FIG. 6, the term of the non-selection period of the equation 1 is larger in the pixel P1a than in the pixel P1c.
1a looks brighter than the pixel P1c, and crosstalk occurs.

As a technique related to this point, for example, Japanese Patent Laid-Open No.
No. 130797 (hereinafter referred to as Reference 1)
The technique described in Japanese Patent No. 6921 (hereinafter referred to as Reference 2) can be cited. The former focused on the influence of waveform distortion in the vicinity of the selection period, and said, "The voltage level of each data signal is set to one of a black level and a white level for a predetermined period immediately before the rising and falling of the scanning pulse, and the rising The voltage level is set to the other of the black level and the white level for a predetermined period immediately after the rising edge and the falling edge. "However, since the effect of the waveform distortion in the non-selected period is improved as a result, the prior art And In addition, the latter technology is "each scanning period,
The period during which the voltage applied to the liquid crystal cell is 0 V is provided. "

FIG. 7 is a diagram in which the technique of the reference 1 is applied to the driving system shown in FIG. 5, the symbol F is a field inversion signal, and the symbols M and N are high potentials (logic 1). At this time, it is a signal that fixes the column electrode drive voltage to a specific potential regardless of the display data. In the case of FIG. 7, the signal M becomes the short-time logic 1 immediately before the rising and falling of the scanning selection signal, and the signal N becomes the short-time logic 1 immediately after the rising and falling of the scanning selection signal. Symbol D
Reference characters a, Db, and Dc represent display data to be displayed on the column electrodes Ya, Yb, and Yc, respectively, and a logic 1 indicates a bright state, and a logic 0 indicates a dark state. Therefore, all the pixels of the column electrode Ya display a bright state, and the column electrode Yb
All the pixels of No. display the dark state, and the pixels on the column electrode Yc repeat the display of the bright state and the dark state for each row. FIG. 7 shows a case where the level of the column electrode drive voltage is set to a dark display state (black level) immediately before the rising and the falling of the scan selection signal, and the short time immediately after the rising and the falling. This is a case where the level of the column electrode drive voltage is set to a bright display state (white level), and the waveform distortion at the time of rising and falling of the scan selection signal and the column electrode drive voltage (Y) is omitted and drawn. There is. The results show that the number of changes in the drive voltage applied to each pixel during the non-selection period is approximately 2 m −2 times, regardless of the display data, and therefore the effective voltage in the field is not changed. Since the term of the selection period is constant, crosstalk is greatly reduced.

However, in the conventional embodiment shown in FIG. 7, there are cases where the crosstalk cannot be sufficiently reduced, and as a result of the investigation, it was found that the following phenomenon occurred.

The electrically equivalent model of the liquid crystal is represented by FIG. In FIG. 8A, CL is an equivalent capacitance of the liquid crystal and RL is an equivalent resistance of the liquid crystal. The liquid crystal is not in direct contact with the electrodes, but faces the electrodes via, for example, an alignment film. Therefore, capacitors Cx and Cy can be considered as equivalent circuits of these films, and rx and ry can be considered as parasitic resistance. For the sake of simplicity, ry and Cy are ignored, the equivalent circuit of FIG. 6B is considered, and the response of the voltage VL applied to the liquid crystal when the stepwise input VI is applied to this circuit is considered. Then, depending on the size of rx and RL, V
L changes as shown in FIG.

That is, in FIG. 9, when the stepwise voltage VI shown in FIG. 9A is applied, (1) VL becomes VI itself when rx = 0 and RL = ∞. (2) When rx = ∞ and RL = ∞, VL is stepwise changed to the voltage E determined by the voltage division ratio of Cx and CL, and then the voltage E is maintained. (3) When rx = A and RL = ∞, VL changes stepwise to the voltage E and then rises based on the time constant determined by rx, Cx, and CL. (4) When rx = ∞ and RL = B, VL changes stepwise to the voltage E and then drops based on the time constant determined by RL, Cx, and CL.

Therefore, in reality, V depends on the values of rx and RL.
Although the change in L is different, in order to simplify the explanation here as well, when the waveforms of Ya and Yc shown in FIG. 7 are considered assuming rx = A and RL = ∞, the results are shown in FIG. It becomes as shown.

In FIG. 10, if the time for fixing the column electrode drive voltage is extremely short regardless of the display data, Ya
After making a stepwise change at the leading edge of period t1,
It rises according to a certain time constant and reaches almost + Vs when a sufficient time has passed. However, since Yc is inverted every selection period, a small voltage is always applied without reaching ± Vs. Therefore, the effective voltage applied to the liquid crystal in the column a during non-selection becomes larger than the effective voltage applied to the liquid crystal in the column c, and the number of changes of the column electrode drive voltage during the non-selection period is the same. Instead, crosstalk occurs.

[0019]

The first problem to be solved by the present invention is to reduce the phenomenon that crosstalk occurs because the effective value of the liquid crystal drive voltage varies depending on the display pattern due to the effect of parasitic resistance. The second problem is that the means used for solving the first problem solves a new problem.

[0020]

If the relationship between Ya and Yc is as shown in FIG. 11, the difference between the effective values of the two will be greatly reduced. From this viewpoint, the inventor of the present invention, as shown in FIGS. 12 and 13 in the prior application 5, displays the potential of the column electrode driving voltage applied to the column electrode group at least in a part of each selection period as display data. It was proposed to fix the potential to a fixed potential regardless of the above, and to invert the polarity of the drive voltage applied to the liquid crystal (inversion within a row) within each selection period.

FIG. 12 shows field inversion, row-by-row inversion (the polarity of the operation selection signal is inverted every time the row changes) and in-row inversion, and display data of each column electrode drive voltage at the leading edge of the selection period. An example of a case where the potential corresponding to the bright state is fixed for a short time regardless of the display state, and each column electrode driving voltage is fixed to the potential corresponding to the dark state for a short time at the trailing edge of the selection period, FIG. 13 shows an example in which field inversion and in-row inversion are performed, and each column electrode drive voltage is fixed at a potential corresponding to a dark state for a short time at the trailing edge of the selection period regardless of display data.

12 and 13, for convenience of explanation,
Although the fixed time of the column electrode drive voltage is drawn long, it is assumed that the fixed time is sufficiently smaller than the selection period, Ya, Yb,
FIG. 14 is obtained by rewriting Yc.

FIG. 14A is a rewrite of FIG. 12, and FIG. 14B is a rewrite of FIG.
In the discussion of reducing the difference in waveform deformation due to charging / discharging via the parasitic resistance, it can be said that the polarity reversal for a very short time can be neglected. Therefore, from this point of view, FIG. Then, except before and after the field inversion, it can be seen that the polarities of Ya and Yb are inverted in the same length of time as the selection period, and the polarity of Yc is inverted in the half of the selection period. .. On the other hand, in FIG. 14B, except before and after the field inversion, the polarities of Ya and Yb are inverted in half the length of the selection period, and Yc is inverted in the same length of time as the selection period. You can see it while you are doing it. Therefore, Ya, Yb
The relationship between Yc and Yc has the same result as the explanatory diagram shown in FIG. 11, the difference in effective voltage between Ya, Yb and Yc is small, and the crosstalk due to the influence of parasitic resistance is dramatically improved.

A detailed examination of FIG. 14 shows that FIG.
In FIGS. 14A and 14B, as described above, Ya, Yb, and Yc are used.
14 is reversed, and the spikes due to the fixed operation of the column electrode drive voltage are ignored, and the number of changes per field for Ya, Yb and Yc is
It can be seen that Yb is half the number of changes in Yc, and in FIG. 14B, Ya and Yb are twice the number of changes in Yc.

That is, when the column electrode drive voltage is not fixed and the same number of fields that are inverted per row and fields that are not inverted per row are combined into one frame, the number of changes in the column electrode drive voltage within one frame is displayed. It is constant regardless of the data.

Therefore, the first means used by the present invention to solve the above-mentioned problems is a column electrode group to which a column electrode drive voltage is applied and a row electrode group to which a row electrode drive voltage based on a scan selection signal is applied. In the driving method of the display device having the above, the polarity of the driving voltage applied to the liquid crystal is reversed (intra-row inversion) within each selection period, and the polarity of the driving voltage is reversed for each row (inversion for each row). It is to mix fields that are not reversed line by line.

The second means used by the present invention to solve the above-mentioned problems is, in addition to the above-mentioned first means, the column electrode drive voltage applied to each column electrode at least at the leading edge of each selection period. That is, the potential of the scan selection signal is set to the non-selection potential until the potential of is almost stable.

A third means used by the present invention to solve the above-mentioned problems is, in addition to the first means, the column electrode drive voltage applied to each column electrode at least at the trailing edge of each selection period. The potential of the scan selection signal is set to the non-selection potential before the potential change of (1) is started.

A fourth means used by the present invention for solving the above-mentioned problems is, in addition to the first means, a potential of the column electrode drive voltage applied to each column electrode at least immediately after the in-row inversion. That is, the potential of the scan selection signal is set to a non-selection potential until the temperature becomes substantially stable.

A fifth means used by the present invention to solve the above-mentioned problems is, in addition to the first means, at least immediately before the in-row inversion, the potential of the column electrode drive voltage applied to each column electrode. Before the change starts, the potential of the scan selection signal is set to a non-selection potential.

In addition to the first means, the sixth means used by the present invention to solve the above-mentioned problem is that the start timing of the change of the column electrode drive voltage is set at the front edge of each selection period. The scan selection signal of the row is set to the non-selection potential, and the scan selection signal of the row is set to the non-selection potential until the column electrode drive voltage is substantially stable to the voltage based on the display data of the row. It is fixed to.

The seventh means used by the present invention to solve the above-mentioned problems is, in addition to the above-mentioned first means, prior to the start of the change of the column electrode drive voltage at the trailing edge of each selection period. Then, the scan selection signal is shifted to the non-selection potential so that the column electrode drive voltage is almost stabilized to the voltage based on the display data of the next row before the end of the selection period.

In addition to the first means, an eighth means used by the present invention to solve the above-mentioned problem is to provide a stabilization period during which each scanning selection signal becomes a non-selection potential during each selection period. In the stable period, the transition of the drive voltage of each column electrode from the voltage based on the display data of the previous row to the voltage based on the display data of the next row is almost completed.

In addition to the first means, a ninth means used by the present invention to solve the above-mentioned problems is that at least a period for which each column electrode drive voltage is predicted to change, a scan selection signal It is to operate so that the potential becomes almost non-selective potential.

The tenth means used by the present invention to solve the above-mentioned problems is, in addition to the above-mentioned second to tenth means, that the high-voltage driving voltage applied to the liquid crystal within the selection period becomes positive and negative. , Setting the time for fixing the operation selection signal to the non-selection potential.

[0036]

By using the above-mentioned first means, the time for which each column electrode drive voltage maintains a constant value is the same as or half the length of the selection period, and as shown in FIGS. The influence difference of the waveform deformation due to the charge and discharge through the resistor is reduced, and the effective voltage in the non-selected period is the average of the field in which the row inversion is performed and the field in which the row inversion is not performed, regardless of the display pattern. In addition, it is possible to minimize the reduction of contrast as well as making them identical. Further, by using the second to tenth means, the problem of waveform distortion in the selection period, which will be described later, can be solved, and the same frame gradation as the conventional one can be performed.

[0037]

FIG. 15 shows a first embodiment of the present invention in which a field (inverts the polarity of the operation selection signal every time the row is changed) is performed while the in-row inversion is performed in each selection period. In this embodiment, T1 ... Tm, hereinafter referred to as T field) and fields for performing inversion for each row (t1 ... tm, hereinafter referred to as t field) are alternately arranged. In FIG. 15, the signal L is a signal instructing to invert every row when the potential is high.

It can be seen from FIG. 15 that the number of changes in the column electrode drive voltage during the non-selected period is the same for P1a, P1b, and P1c if the T field and the t field are averaged. Without change, the effective value during the non-selected period does not change. It is also clear that the effect of parasitic resistance is reduced. Furthermore, comparing FIG. 12 or FIG. 13, since there is no fixed period of the column electrode drive voltage, the effective value in the bright state may decrease or the effective value in the dark state may increase as shown in FIGS. 12 and 13. It is also clear that the reduction in contrast is improved because it is not present.

Although FIG. 15 is drawn with the waveform distortion omitted, FIG. 16 is obtained by rewriting FIG. 15 by adding the waveform distortion to the column electrode drive voltages Ya, Yb, and Yc.

When the drive voltage waveform applied to the pixels P1a, P1b and P1c in the selection period T1 in FIG. 16 is examined, Yc changes at the leading edge of T1 and therefore the drive voltage effective value decreases in P1c. Waveform distortion occurs in the direction
Since a and Yb do not change, waveform distortion does not occur in P1a and P1b. On the other hand, when the drive voltage waveform applied in the selection period t1 is examined, Ya and Yb change at the leading edge of t1, so that waveform distortion occurs in P1a in the direction in which the effective drive voltage decreases, and P1b drives. The waveform distortion does not occur in the direction in which the effective voltage value increases, but the waveform distortion does not occur in P1c because Yc does not change. A similar argument exists immediately after the inversion.

Considering the crosstalk from the waveform of FIG. 16, the number of changes of the column electrode drive voltage in the non-selection period is P1 when the average of T field and t field is taken.
The same applies to a, P1b, and P1c, and the effective value of the high voltage applied during the selection period is also the same for the pixels of the same display if the average of T1 and t1 is taken. Therefore T field and t
If the fields are combined into one frame, the effective voltages are the same for pixels in the same display state within one frame, and therefore crosstalk does not occur. Further, the contrast decrease is smaller than that in the case of FIG. 13 because it is only due to the influence of the waveform distortion.

However, as is apparent from FIG. 16, the pixels P1a and P1c are
It can be seen that the positive DC component remains in P1b and the negative DC component remains in P1b. In order to avoid this, the polarity of the drive voltage may be inverted (hereinafter referred to as frame inversion) at a cycle that is an integral multiple of the frame. As a result, it is possible to obtain a high-quality display image without problems when a gradation is controlled by controlling a display pattern over a plurality of fields, that is, when so-called frame gradation is not performed. However, when the frame gradation display is performed, the residual DC component may be a problem. In the case of the conventional technique, the field inversion is performed to prevent the DC component from remaining. If the display pattern is changed in units of two fields, the frame gradation can be performed without leaving the residual DC component. However, if the frame is inverted in FIG. 16, the DC component remains unless the display pattern is operated in units of at least 4 fields.

FIG. 1 shows a second embodiment of the present invention.
In the sixth embodiment, the second to fifth solving means are further used, and a period until the potential change of each column electrode drive voltage (Y) becomes substantially stable at the leading edge of each selection period. , The scanning selection signal is held at the non-selection potential, and at the trailing edge of each selection period, the scanning selection signal is shifted to the non-selection potential prior to fixing the potential, and after the transition is almost completed, While fixing the potential of the column electrode drive voltage is started, the scan selection signal is shifted to a non-selection potential before each column electrode drive voltage starts changing at the time of inversion in the row,
After the potential change of each column electrode drive voltage is almost finished, the scanning selection signal is shifted to the selection potential again, and the operation selection is performed so that the high voltage drive voltage applied to the liquid crystal becomes equal to the positive and negative in the selection period. This is to set the time for fixing the signal to the non-selection potential. Specifically, when the signal H has a high potential, the scanning selection signal may be forcibly set to a non-selection potential, and the time during which the signal H has a high potential may be adjusted.

Comparing the operation waveforms shown in FIG. 1 with the case of FIG. 16, it is found that the contrast deterioration due to the waveform distortion is significantly improved and that no DC component remains in each frame. It is possible to perform frame gradation in units of two fields, as in the condition of.

By the way, for example, in the embodiment of FIG. 1, if the definition of "selection period" is changed, the following interpretation is established. (1) As shown in FIG. 17A, if the time from the time when the operation selection signal of one row shifts to the selection potential to the time when the operation selection signal of the next row shifts to the selection potential is defined as the selection period,
In FIG. 1, the operation performed at the leading edge of the selection period is performed at the trailing edge of the selection period. That is, at the trailing edge of each selection period, the scan selection signal is shifted to the non-selection potential before the change of the column electrode drive voltage is started, and the column electrode drive voltage is changed to the next level before the end of the selection period. It will be almost stable to the voltage based on the display data of the row,
The seventh and tenth solving means or the ninth solving means will be used.

(2) As shown in FIG. 17B, the operation selection signal of a certain row is finally selected (except before and after the inversion within the row) from the selection potential to the non-selection potential from the operation selection of the next row. If the time until the signal finally shifts from the selection potential to the non-selection potential is defined as the selection period, the operation performed at the trailing edge of the selection period in FIG. Will be seen. That is, at the leading edge of each selection period, the start timing of the change in the column electrode drive voltage is started after the scan selection signal of the preceding row becomes substantially the non-selection potential, and
Until the column electrode drive voltage becomes substantially stable to the voltage based on the display data of the row, the scan selection signal of the row is fixed to the non-selection potential, and the sixth and tenth solving means, or The solution of the ninth solution will be used.

(3) As shown in FIG. 17C, the selection potential finally shifts to the non-selection potential (except before and after the inversion within the row) from the time when the operation selection signal of a certain row reaches the selection potential. If the time until is defined as the selection period, the operations performed at the leading edge and the trailing edge of the selection period in FIG. 1 are performed between the selection periods. That is, a stabilization period in which all the scan selection signals become non-selection potential is provided between each selection period, and within the stabilization period, the voltage based on the display data of the previous row of the voltage of each column electrode drive voltage is changed to the next row. The transition to the voltage based on the display data is almost completed, and the solution means of the eighth and tenth solution means or the ninth solution means is used.

The embodiment of FIG. 1 of the present invention is summarized as follows: "The polarity of the drive voltage applied to the liquid crystal is inverted (intra-row inversion) within each selection period, and the polarity of the drive voltage is inverted (row-by-row). Fields to be inverted) and fields not to be inverted row by row are mixed, and at least during the period when the column electrode drive voltage is expected to change, the operation is performed so that the potential of each scan selection signal becomes substantially a non-selective potential. " become.

The above description of the embodiment is made assuming that the parasitic resistance in FIG. 9B is rx = A and RL = ∞, but for other values, the waveform is different and the effect of the present invention is obtained. Does not change. Further, in addition to the parasitic resistance shown in FIG. 9A, the parasitic resistance also exists between the adjacent column electrodes as shown by rz in FIG. 18, and influences each other when the adjacent column electrode drive voltages are different. There may be a case where the display state changes, but in this case as well, it can be greatly improved by implementing the present invention.

[0050]

As described above, according to the present invention, the crosstalk due to the influence of the number of changes of the column electrode drive voltage during the non-selection period and the crosstalk due to the influence of the parasitic resistance are both suppressed, and the contrast is reduced. The decrease is suppressed,
It is possible to provide a very good display device, and it is possible to perform frame gradation in units of two fields as in the conventional condition.

The liquid crystal panel is in the direction of high definition or miniaturization, the equivalent capacitance decreases as the electrode area decreases, and the parasitic resistance rz decreases, for example, as the space between the electrodes decreases. The time constant with the capacity is also decreasing. As a result, the problems taken up as the problems to be solved by the present invention are expected to grow more and more in the future, but the present invention can solve all possible problems.

[Brief description of drawings]

FIG. 1 is an operation waveform diagram showing a second embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a liquid crystal drive circuit.

FIG. 3 is a more detailed block diagram of a liquid crystal drive circuit.

FIG. 4 is a waveform diagram showing a method of setting a liquid crystal drive voltage.

FIG. 5 is a diagram showing a basic drive waveform of liquid crystal.

FIG. 6 is a waveform diagram for explaining problems of a basic driving method.

FIG. 7 is an operation waveform diagram for explaining a conventional example.

FIG. 8 is an equivalent circuit diagram of a liquid crystal for explaining the problems of the conventional example.

FIG. 9 is an operation waveform diagram for explaining the influence of parasitic resistance.

FIG. 10 is an operation waveform diagram for explaining the influence of parasitic resistance on the effective value of the liquid crystal drive voltage.

FIG. 11 is an operation waveform diagram for explaining the operation of the present invention.

FIG. 12 is a reference operation waveform diagram for explaining the present invention.

FIG. 13 is a reference operation waveform diagram for explaining the present invention.

FIG. 14 is an operation waveform diagram for explaining the effect of the present invention.

FIG. 15 is an operation waveform diagram showing the first embodiment of the present invention.

FIG. 16 is another operation waveform diagram showing the first embodiment of the present invention.

FIG. 17 is an explanatory diagram illustrating another embodiment of the present invention.

FIG. 18 is an equivalent circuit diagram showing another parasitic resistance.

[Explanation of symbols]

 201 control circuit 202 column electrode drive circuit 203 row electrode drive circuit 204 drive power supply circuit 301 storage circuit 302 holding circuit 303 voltage switching circuit 304 output circuit 305 scanning signal generation circuit 306 output circuit 307 display panel

Claims (10)

[Claims] 1. A driving method of a display device having a column electrode group to which a column electrode driving voltage is applied and a row electrode group to which a row electrode driving voltage based on a scanning selection signal is applied, in each selection period. In this case, the polarity of the drive voltage applied to the liquid crystal is inverted (intra-row inversion), and a field for inverting the polarity of the drive voltage for each row (inversion for each row) and a field for not inverting each row are mixed. To drive the display device. 2. At least the leading edge of each selection period,
The driving method of the display device according to claim 1, wherein the potential of the scan selection signal is set to a non-selection potential until the potential of the column electrode drive voltage applied to each column electrode is substantially stabilized. 3. At least at the trailing edge of each selection period,
2. The driving method of the display device according to claim 1, wherein the potential of the scan selection signal is set to a non-selection potential before the potential change of the column electrode drive voltage applied to each column electrode is started. 4. At least immediately after the inline inversion,
The driving method of the display device according to claim 1, wherein the potential of the scan selection signal is set to a non-selection potential until the potential of the column electrode drive voltage applied to each column electrode is substantially stabilized. 5. At least immediately before the inline inversion,
2. The driving method of the display device according to claim 1, wherein the potential of the scan selection signal is set to a non-selection potential before the potential change of the column electrode drive voltage applied to each column electrode is started. 6. At the leading edge of each selection period, the start timing of the change of the column electrode drive voltage is started after the scan selection signal of the preceding row becomes substantially the non-selection potential, and the column electrode drive voltage is changed. The driving method of the display device according to claim 1, wherein the scan selection signal of the row is fixed to a non-selection potential until is substantially stable to the voltage based on the display data of the row. 7. A scanning selection signal is shifted to a non-selection potential at the trailing edge of each selection period prior to the start of a change in the column electrode drive voltage, and the column electrode is preceded by the end of the selection period. 2. The driving method of the display device according to claim 1, wherein the driving voltage is made substantially stable to the voltage based on the display data of the next row. 8. A stabilization period in which all scanning selection signals are at non-selection potential is provided between each selection period, and within the stabilization period, each column electrode drive voltage is based on the display data of the preceding row. The driving method of the display device according to claim 1, wherein the transition from the voltage to the voltage based on the display data of the next row is almost completed. 9. The display according to claim 1, wherein the operation is performed such that the potential of each scan selection signal becomes substantially a non-selection potential at least during a period in which each column electrode drive voltage is predicted to change. Device drive system. 10. The method according to claim 1, wherein the operation selection signal is fixed to a non-selection potential so that the high voltage drive voltage applied to the liquid crystal during the selection period becomes equal to positive and negative. The driving method of the display device according to claim 3, claim 4, claim 5, claim 6, claim 7, claim 8, or claim 9.