JP3270086B2 - Liquid crystal display - Google Patents

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 driving circuit for applying a scanning selection signal to the row electrodes, and a binary display on the column electrodes. A column electrode drive circuit that applies a column electrode drive signal based on data, a drive power supply circuit, and a control circuit. Each display pixel has a drive voltage applied to both ends of each pixel during a selection period and a non-selection period. The present invention relates to a drive circuit of a display device driven in relation to an effective value and displaying two display states of light and dark based on a difference between effective values 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 diagram of a general liquid crystal display device. A plurality of row electrodes X1, X2,... Xm are connected to a row electrode driving 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. It is assumed that the display data source is included in the control circuit 201.

FIG. 3 shows the column electrode driving 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 for holding an output of the storage circuit 301 during one selection period of a scanning selection signal; a voltage switching circuit 303 for inverting an output of the data holding circuit 302 based on a polarity inversion signal from the control circuit 201; An output circuit 304 generates a column electrode driving voltage to be applied to each column electrode of the display panel 307 based on an output of the voltage switching circuit 303. The row electrode driving circuit 203 controls the control signal including a clock signal from the control circuit 201. And a scan signal generation circuit 305 for generating a timing of a row electrode scan selection signal, and a scan selection signal to be given to each row electrode of the display panel 307 by an output signal of the scan signal generation circuit 305 and a control signal from the control circuit 201. The output circuit 306 generates a signal.

FIGS. 4 (a) and 4 (b) are diagrams showing a typical method of setting the voltages applied to the row electrodes and the column electrodes when driving the liquid crystal display device shown in FIGS. Yes, FIG. 4
FIG. 4A shows a method using six levels of voltages V1 to V6, and FIG. 4B shows a method using four levels of voltages ± Vc and ± Vs. The present invention is applicable to any of the methods, but the description will be made on the case of using the method of FIG.

FIG. 5 shows a more detailed driving waveform when the driving method shown in FIG. 4B is employed. In FIG. 5, periods T1 and t1 correspond to the first row electrode X1. The periods T2 and t2 are the periods for selecting the second row electrode X2, and the periods Tm and tm are the periods for selecting the m-th row electrode Xm in the same manner. Period T1
To Tm and the periods t1 to tm are defined as one field, respectively, the pixels of the first row electrode X1, P11
P1 to P1n are selected only in the period T1 or t1 in one field, and the other periods are referred to as non-selection periods.

When the potential applied to the row electrode during the non-selection period is defined as a reference potential (0 V), + Vc is applied to the row electrode X1 during the period T1, and 0 V is applied to the other row electrodes.
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, during the period Tm, + V is applied to the row electrode Xm.
c is applied, and 0V is applied to the other row electrodes.
In the next field, -Vc is applied to the row electrode X1 during the period t1, 0 V is applied to the other row electrodes, -Vc is applied to the row electrode X2 during the period t2, and so on. 0V is applied to the row electrode, and thereafter, -Vc is applied to the row electrode Xm during the period tm.
0 V is applied to the other row electrodes. This method is called a field inversion method, in which the polarity of the liquid crystal driving voltage is inverted every k (k = 1, 2,...) Fields. In the inversion method, in addition to field inversion, inversion every L rows (L = 1, 2,...)
・), There is in-line inversion.

On the other hand, regarding the column electrodes, three column electrodes Ya
, Yb, Yc. It is also assumed that the liquid crystal is of a type that displays a bright state by a high applied voltage. The display of all the pixels on the column electrode Ya is in a bright state, the display of all the pixels on the column electrode Yb is in a dark state, and the display of the pixels on the column electrode Yc alternates between a bright state and a dark state. In this case, -Vs is applied to the column electrode Ya during all of the periods T1 to Tm, and + Vs is applied to all of the periods t1 to tm. To the column electrode Yb, + Vs is applied over the entire period from T1 to Tm, and -Vs is applied over the entire period from t1 to tm. The column electrode Yc
, Tm-1 and t2, t4.
,... Tm are applied with -Vs, and the period T2,
T4,... Tm and t1, t3,.
s is applied.

That is, a 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 is | Vc + Vs | When + Vc is applied, -Vs is applied, and when the row electrode drive voltage is -Vc, + Vs is applied. In the selection period for displaying a dark state, the absolute value of the drive voltage applied to both ends of the liquid crystal is | V c -Vs | (in the case of the row electrode driving voltage + Vc + Vs, the row electrode driving voltage in the case of -Vc -Vs) to become such a column electrode driving voltage is applied.

At this time, a pixel P1a formed at the intersection of the row electrode X1 of the first row and the column electrode Ya, and a pixel P1a formed at the intersection of the row electrode X1 of the first row 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
Absolute value of the drive voltage applied to 1c is at the selection period | V c + Vs |, is at the non-selection period | Vs |, and the effective voltage are both represented by the number 1 of over one field As a result, the pixels P1a and P1c both exhibit the bright state. The absolute value of the drive voltage applied to the pixel P1b is at the selection period | V c -Vs |, is at the non-selection period | Vs |, and the number of effective voltage over one field 2 The pixel P1b assumes the dark state.

(Equation 1)

(Equation 2)

In equations (1) and (2), (Vc ± Vs) 2 / m
Is a term relating to the selection period, and is (m-1) · Vs2
The term / m relates to the non-selection period. The contrast between the bright state and the dark state is better when the value of V1 / V2 is larger.

The above description is based on the ideal condition. Actually, 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 its 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 during the non-selection period. Therefore, the pixels P1a and P1c do not have the same display state, and this is one of the causes of crosstalk.
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.
The pixel 1a looks brighter than the pixel P1c, and crosstalk occurs.

Japanese Patent Application Laid-Open No.
The technology described in JP-A-130797 (hereinafter referred to as Reference 1) is raised. This technique focuses on the effect of waveform distortion near the selection period, and has a different technical idea from the present application focusing on the influence of waveform distortion in a non-selection period. Since the technical idea of the present application extends, the reference is referred to as a prior art.

In the technique of Reference 1, 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 a scanning pulse, and the voltage at the time of the rising and falling is set. The voltage level is set to the other of the black level and the white level for a predetermined period immediately after. "
If this is applied to the case shown in FIG. 5 of the present application, the result is shown in FIG.

FIG. 7 shows a state in which the level of the column electrode drive voltage is set to a dark display state at the time Δt 1 immediately before the rising and falling of the scanning selection signal, and the time Δt 2 immediately after the rising and falling of the column. This is a case where the level of the electrode drive voltage is set to the bright display state, the scan selection signal has no distortion, and the column electrode drive voltage (Y) has waveform distortion at the rise and fall. Examination of the results based on the concept of the present application reveals that the number of changes in the drive voltage applied during the non-selection period of each pixel is almost 2m−2 times regardless of the display data. Since the term of the effective voltage in the non-selection period is constant, crosstalk is greatly reduced.

FIG. 7 shows the driving voltages applied to the pixels P1a, P1b, and P1c. FIG. 8 shows the driving voltages applied to the pixels P1a, P2a, P1b, and P1a.
This shows the drive voltage applied to P2b. Focusing on the drive voltage applied to both ends of the liquid crystal pixel during the selection period in FIG. 8, it can be seen that the values are different between the first row and other rows even in the same display state. That is, the pixel P1a
The pixel P2a and the pixel P2a both show a bright display state, but a difference is recognized in the waveform (hatched portion) of the drive voltage applied during the selection period.
Similarly, both the pixel P1b and the pixel P2b show a dark display state, but the waveform of the drive voltage applied during the selection period (shaded area)
Differences are observed.

In the case of FIG. 8, the pixels in the first row always look brighter than the pixels in other rows in the same display state. This phenomenon is caused by a driving method adopted by many OA display devices, that is, a method in which a panel is divided into two parts vertically and each is driven independently. It appears as a fatal disadvantage that the brightness looks different between the top and bottom.

[0017] Figure 9 is an example not performing a field inversion, in the case of actual施例proposed In Figure 10 of JP-A-5-127622 Publication which is the present invention's prior application (hereinafter referred to as citation 2) Show. In FIG. 9, symbol F indicates a field inversion signal, symbol L indicates a row-by-row inversion signal, and symbol I indicates an in-row inversion signal. The scanning selection signal applied during the selection period is F,
When L and I are all low potential (logic 0), or when only one of them is 0, the potential becomes high, and in other cases, it becomes low potential. Symbols M and N are signals for fixing the column electrode drive voltage to a specific potential regardless of display data when the potential is high (logic 1). Da, Db, Dc
Is a signal indicating display data to be displayed on each pixel on the column electrodes Ya, Yb, Yc, where a logic 1 indicates a bright state and a logic 0 indicates a dark state. Accordingly, all pixels on the column electrode Ya are displayed in a bright state, all pixels on the column electrode Yb are displayed in a dark state, and pixels on the column electrode Yc are displayed in a bright state and a dark state alternately.

In the case of FIG. 9, the signals F and L are always 0, so that neither field inversion nor row-by-row inversion is performed. Instead, the signal I repeats 0 and 1 in each selection period to perform in-row inversion. The signal M becomes logic 1 for the time Δt1 immediately before the rising and falling of the scanning selection signal, and the signal N always maintains 0.

A comparison of the waveforms P1a and P2a shown in FIG. 9 shows that there is no difference between them. That is, it can be seen that the difference between the drive voltage applied to each pixel in the first row and the drive voltage applied to the pixels in the other rows in the same display state during the selection period is due to the influence of field inversion.

In order to solve this problem, the present inventor disclosed in Japanese Patent Application Laid-Open No. Hei 6-110409 (hereinafter referred to as Reference 3) different from Reference 2 (1) the voltage polarity of the scan selection signal is set to k. (K = 1, 2
..) Inverting every field period, and fixing the column electrode driving voltage to a voltage corresponding to a bright state or a dark state for a fixed time within a selection period selected by the scanning selection signal regardless of display data. A drive system for a display device, wherein the voltage to be fixed, which corresponds to a bright state and a dark state, is inverted every time the field inversion is performed. (2) The driving method of the display device according to (1), wherein the voltages corresponding to the bright state and the dark state to be fixed are further inverted at a period longer than the k-field period. (3) The direction of field inversion is further reversed at a period longer than the k-field period. (1)
4. The driving method of the display device according to 1. Suggested.

Among them, (1) is for solving the above problem, but (2) and (3) show that when (1) is carried out, a DC component is applied to the liquid crystal in a long term. This is a device that eliminates the danger that the display can be sufficiently effective if the same display content lasts for a long period of time.However, if the display content changes frequently, the DC component can be completely removed. There is no possibility.

[0022]

Accordingly, an object of the present invention is to perform field inversion and to make the number of times of switching of the column electrode driving voltage within a non-selection period substantially constant regardless of display data. Another object of the present invention is to prevent a DC component from remaining in a liquid crystal in any display state in a display device that fixes a column electrode drive voltage.

[0023]

A first means used by the present invention to solve the above-mentioned problems is that a column electrode drive voltage is applied.
Column electrode group and row electrode drive voltage based on scan selection signal
Is applied, and the row electrode drive voltage,
Intra-line inversion, line-by-line inversion, or k (k = 1, 2,...)
At least the previous of the field inversions every field period
The field inversion is performed, and the line-by-line inversion is not performed.
One of the leading edge or trailing edge of each selection period based on the scan selection signal
In each case, the drive voltage of each column electrode is
Fixed to one of the voltages corresponding to the bright state and dark state
With either the leading or trailing edge of each selection period.
And the column electrode drive voltage is clear regardless of the display data for a certain period of time.
Liquid crystal table fixed to the other of the voltage corresponding to the state and dark state
Display device or only the field inversion and in-line inversion
No inversion is performed for each row, and each selection based on the scan selection signal is performed.
A fixed time only at the trailing edge of the leading or trailing edge of the selection period
The column electrode drive voltage during the bright state and the dark state is independent of the display data.
In a liquid crystal display device fixed to one of the voltages corresponding to the state
And the selection period immediately before or immediately after the field inversion
Is the field inversion correction period, and the field inversion correction
The column electrode driving voltage at the trailing edge of the period is represented by display data
Table with fixed voltage at the trailing edge of the next selection period
If the voltage is fixed to the same display state as the display state,
In addition, the bright display is visually recognized for the row corresponding to the correction period.
It is necessary to have means to prevent this.

A second means used by the present invention to solve the above-mentioned problem is a column electrode group to which a column electrode drive voltage is applied.
And a row electrode drive voltage based on the scan selection signal is applied
A row electrode group, wherein the row electrode drive voltage is inverted in a row,
Every inversion, or k (k = 1, 2,...) Field period
At least the field in each field inversion
The scan selection signal is inverted and row-by-row is not inverted.
At either the leading or trailing edge of each
Each column electrode drive voltage for a fixed time
And one of the voltages corresponding to the dark state.
A fixed time at the leading or trailing edge of the selection period
Each column electrode drive voltage is bright and dark regardless of display data
Liquid crystal display device fixed to the other of the voltages corresponding to the state or
Only the field inversion and the in-line inversion are performed.
Not performed, leading edge of each selection period based on the scan selection signal.
Or each column electrode is driven for a certain time only at the trailing edge of the trailing edge
The voltage corresponds to the bright state and the dark state regardless of the display data
In a liquid crystal display device fixed to one of the voltages,
A field inversion correction period is provided immediately before or immediately after the field inversion, and the column electrode drive voltage at the trailing edge of the field inversion correction period is changed to a fixed voltage at the trailing edge of the first row selection period to be displayed next. To the same display state as
It is to fix to the corresponding voltage .

According to a third aspect of the present invention, there is provided a column electrode group to which a column electrode driving voltage is applied.
And a row electrode drive voltage based on the scan selection signal is applied
A row electrode group, wherein the row electrode drive voltage is inverted in a row,
Every inversion, or k (k = 1, 2,...) Field period
At least the field in each field inversion
Inversion and row-by-row inversion are performed, and each selection is performed based on the scan selection signal.
For a certain period of time at either the leading or trailing edge of the
The pole drive voltage is set to the bright state and the dark state regardless of the display data.
Fixed to one of the applicable voltages and before each selection period.
Driving each column electrode for a certain time at the other edge or trailing edge
The voltage corresponds to the bright state and the dark state regardless of the display data
A liquid crystal display or said field fixed to the other side of the voltage
Only inversion and row-by-line inversion are performed.
The leading or trailing edge of each selection period based on the scan selection signal
Display the driving voltage of each column electrode for a certain time only on the trailing edge
One of the voltages corresponding to the bright state and dark state regardless of the data
In the liquid crystal display device fixed to the
Field inversion correction period provided immediately before or after, the display by at fixed voltage to the trailing edge of the first row selection period in which the in the column electrode driving voltage to the trailing edge of the field inversion correction period, and then displays It corresponds to the display state opposite to the state
It is fixed to voltage .

A fourth means used by the present invention to solve the above-mentioned problem is a column electrode group to which a column electrode driving voltage is applied.
And a row electrode drive voltage based on the scan selection signal is applied
A row electrode group consisting of an odd number of rows;
Pressure, in-row inversion, row-by-row inversion, or k (k = 1, 2,...)
・) Of the field inversions for each field cycle,
In each case, the field inversion and the row inversion are performed, and the scanning selection is performed.
At the leading or trailing edge of each selection period based on the selection signal.
And the column electrode drive voltage is clear regardless of the display data for a certain period of time.
State and dark state.
At the leading or trailing edge of each selection period.
Each column electrode drive voltage for a fixed time
LCD device fixed to the other of the voltages corresponding to dark and dark conditions
Alternatively, only the field inversion and the line-by-line inversion are performed, and the
The inversion is not performed, and in each selection period based on the scan selection signal,
Each row for a certain time only at the trailing edge of the leading or trailing edge
Electrode drive voltage in bright state and dark state regardless of display data
In a liquid crystal display device fixed to one of the applicable voltages,
Select the selection period immediately before or immediately after the field inversion.
Field inversion correction period,
The column electrode driving voltage at the trailing edge is calculated based on display data.
Display state by fixed voltage at the trailing edge of the next selection period
Is fixed to the voltage corresponding to the display state opposite to the above .

[0027]

By using the [action] said means, the same is applied to the pixel display state drive voltage which lines even same <br/> one next to the on rows to display, yet the average drive voltage becomes 0 the 2k field, the liquid crystal No DC component remains in the.

[0028]

FIG. 10 shows a first embodiment of the present invention.
8 is an example in which only field inversion is performed, and in the field from T1 to Tm (hereinafter referred to as T field), the column electrode drive voltage is darkened at the trailing edge of each selection period. Fix to the voltage corresponding to the display state,
At the leading edge of each selection period, the column electrode driving voltage is fixed to a voltage corresponding to a dark display state, and in the field from t1 to tm (hereinafter referred to as t field), the column electrode driving voltage is set at the leading edge of each selection period. In this case, the column electrode driving voltage is fixed to a voltage corresponding to a dark display state, and the column electrode driving voltage is fixed to a voltage corresponding to a dark display state at a trailing edge of each selection period.

The periods Tx and tx indicate a field inversion correction period (hereinafter referred to as a correction period at the end), and the column drive voltage is applied to the trailing edge of the period Tx and the selection period t1 of the first row displayed next. Is fixed at the voltage corresponding to the same display state as that fixed at the trailing edge, and the same display state as that fixed at the trailing edge of the selection period T1 of the first row to be displayed next at the trailing edge of the period tx. Is fixed to the voltage corresponding to. P1a in FIG. 10,
Comparison of P2a shows that there is no difference in the drive voltage applied to both ends of the liquid crystal during each selection period. Similarly, P
Comparison of 1b and P2b shows that there is no difference in the drive voltage applied to both ends of the liquid crystal during each selection period. Therefore, the average value of the driving voltages applied to the pixels in the same display state during the selection period of the T field and the t field is the same regardless of the position of the row.
The disadvantage that the display state of the row is different from that of the other row electrodes is eliminated.

In FIG. 10, the correction period does not need to be the same width as the selection period, and may be longer or shorter. However, for simplicity, the correction period is selected in the following description. It shall be the same length as the period. In this case, it is necessary to examine whether the correction period can be used as the display period.

There are two possible positional relationships between the field inversion timing and the correction period. That is, in FIG. 10, the case where the field inversion signal is at the timing of F1 and the case of F
There is a case of timing 2. Assuming that the field inversion signal is F1, Ya becomes as shown by a solid line in the periods Tx and tx, and has a waveform different from that of the other preceding rows, which is inconvenient for display. On the other hand, if the field inversion signal is F2, Ya becomes as shown by a dashed line in the periods Tx and tx, and also has a different waveform from other succeeding rows, which is inconvenient for display. Therefore, in the case of the embodiment of FIG. 10, the display in which the correction period is the selection period is not performed.

Whether or not to output the selection voltage during the correction period is optional, and the output may be connected to a dummy row whose output is hidden by a cut-off frame, or may not be connected. However, in a structure in which the column electrodes are separately driven vertically and separately, the dummy rows for the upper column electrodes and the dummy rows for the lower column electrodes must not be formed in the center of the screen. The display data of each column in the correction period may be arbitrary, but is desirably either black display or white display.

In FIG. 10, the field inversion signal is F2
Means that the line immediately after the field inversion is not displayed . Also the above field inversion correction
A new period can be set up, or
Obviously, the selection period may be diverted. For example
FIG. 10 shows that there are m selection periods in the original field.
It is assumed that one correction period is provided for this.
But this has x selection periods in the original field.
Thus, one of them may be considered as a correction period. So
In the case of FIG. 10, the information is described from “0030” to “0032”.
As mentioned, the selected period, which is the correction period, is displayed
Should not be performed. In this regard,
The same applies to the embodiment.

FIGS. 11 and 12 show a second embodiment of the present invention, which is a driving system employing both row-by-row inversion and field inversion. The driving system shown in FIG. In this embodiment, the number of selection periods excluding the correction period of one field is set to an even number. FIG.
1 shows a case where a correction period is provided prior to the inversion of the field inversion signal F, and FIG. 12 shows a case where a correction period is provided after the inversion of the field inversion signal F. Column drive voltage in Figure 1 1 is at the trailing edge of period Tx, is then secured to a voltage corresponding to the opposite display state as being fixed at the trailing edge of the selection period t1 of the first line to be displayed, Also at the trailing edge of the period tx, the voltage is fixed to a voltage corresponding to the display state opposite to that fixed at the trailing edge of the selection period T1 of the first row to be displayed next. FIG.
Comparing P1a and P2a of No. 1 shows that there is no difference between the drive voltages applied to both ends of the liquid crystal during each selection period. Similarly, when P1b and P2b are compared, it can be seen that there is no difference in the drive voltage applied to both ends of the liquid crystal during each selection period.

FIG. 11, when the correction period in the case of FIG 12 is to examine whether the displayable period in the case of FIG. 1 1 Tx, t
In x, Ya and Yb are as shown in the figure, and have the same waveform as the other preceding rows, so that display is possible. On the other hand, in the case of FIG. 12, Ya and Yb are as shown in the figure in the periods Tx and tx, and also have the same waveform as the other succeeding rows, so that they can be displayed. Therefore , FIG.
In the case of the twelfth embodiment, the correction period may be displayed as the selection period. However, in this case, the number of display lines is odd.

In the embodiment shown in FIGS . 11 and 12 , as in the embodiment shown in FIG. 10, the voltage is applied during the selection period of the T field and the t field of the pixel in the same display state. It is clear that the average value of the drive voltage is the same regardless of the row position.

In the case where the display in which the period Tx is the selection period is not performed in FIG. 12 , the line immediately after the field inversion is simply not displayed.

FIG. 13 shows a third embodiment in which the present invention is applied to a drive system employing in-row inversion and field inversion.
This is an example of the driving method shown in FIG. Similar column drive voltage and 10 In Figures 1 to 3 at the trailing edge of period Tx, then corresponding to the same display state and being secured at the trailing edge of the selection period t1 of the first line to be displayed At the trailing edge of the period tx, the voltage corresponding to the same display state as that fixed at the trailing edge of the selection period T1 of the first row to be displayed next. Figure 1 3 P1a, it is clear there is no difference in the driving voltage applied to the liquid crystal across each selection period Comparing P2a. Similarly, P1b, P
Comparison of 2b shows that there is no difference in the drive voltage applied to both ends of the liquid crystal in each selection period. Although Figure 1 3 shows the case where the correction period is provided prior to the field inversion, may of course be provided after the field reversal. Examination as to whether the correction period is suitable for display is the same as in the case of FIG.

[0039] Also in the embodiment shown in FIG. 1 3 10,
As in the case of the embodiment shown in FIGS . 11 and 12 , the average value of the driving voltages applied to the pixels in the same display state during the selection period of the T field and the t field is the same regardless of the row position. It is obvious.

FIG. 1 shows a fourth embodiment of the present invention in which the present invention is applied to a drive system employing all of in-line inversion, line inversion, and field inversion . The drive system shown in FIGS. It is an example about. FIG. 1 shows a case where the number of selection periods excluding the correction period of one field is an even number and a correction period is provided prior to the inversion of the field inversion signal F , as in FIGS. The driving voltage is fixed at the trailing edge of the period Tx to a voltage corresponding to the display state opposite to that fixed at the trailing edge of the selection period t1 of the first row to be displayed next. The voltage is fixed to a voltage corresponding to the display state opposite to that fixed at the trailing edge of the selection period T1 of the first row to be displayed next. P1 in FIG.
By comparing a and P2a, it can be seen that there is no difference in the drive voltage applied to both ends of the liquid crystal during each selection period. Similarly, when P1b and P2b are compared, it can be seen that there is no difference in the drive voltage applied to both ends of the liquid crystal during each selection period.

The examination as to whether the correction period can be displayed in the case of FIG. 1 is the same as in the case of FIGS. 11 and 12 , and FIG.
It is apparent that the average value of the drive voltage applied during the selection period of the T field and the t field is the same regardless of the row position in the embodiment shown in FIG.

In the embodiments of FIGS. 10 , 11 , 12 , 13 and 1, the bright state may be replaced with the dark state, and the dark state may be replaced with the bright state.

The column electrode drive voltage Y applied to the column electrodes is changed from the case where the field inversion signal is set to F2 in FIGS . 11, 12, 1 and 10, and the case where the correction period is changed after the field inversion in FIG. Logically, logic X, P,
When Q is represented by Equation 3, Y is given by Equation 4.

(Equation 3)

(Equation 4)

Assuming that R = 1 in Equation 4, the above-described replacement of the bright state as a dark state and the dark state as a bright state is performed.

[0045] In FIG 1 3 in FIG. 10 a field inversion signal F
When it is set to 1, the logic of the signals F and R may be set to Equation 5.

(Equation 5)

[0046] Figure 1 4 is a circuit diagram showing an embodiment that realizes the number 5 in detail. 1 part of 4 (a) is a part that can be made common to the whole, provided in the column electrode driving circuit 202 shown in FIG. 3, the signal R from the control circuit 201, F, L, I , M, N, etc., may be provided in the control circuit 201, and the signals J, K may be sent from the control circuit 201 to the column electrode drive circuit 202.
Of course, the logical conversion may be further performed, and the logical conversion may be provided separately for both the control circuit 201 and the column electrode driving circuit 202.

[0047] FIG 1 4 (b) is a portion including the display data to the logic requires each corresponding to each column electrode,
In FIG. 13, the voltage switching circuit 303 and the output circuit 30
4 shows an example of the configuration.

The above description has been given of the case of setting the voltage as shown in FIG. 4 (b). In the case of setting the voltage as shown in FIG. 4 (a), if the logic S is defined as shown in Equation 6, V1, V3, V4
, V6 are obtained by the following equation (7).

[0049]

As described above, according to the present invention, the number of changes of the column electrode driving voltage applied to each column electrode during the non-selection period in one field is made substantially the same regardless of the display pattern. In the liquid crystal display device, the amount of change in the effective value due to the waveform distortion is equalized, crosstalk is reduced, and the fatal disadvantage that the display state of the first row is different from the other rows by the field inversion operation can be eliminated. In addition, a DC component does not remain in the liquid crystal, which is highly effective in providing a high-performance display device. Although the above description has been given of the case of the display device of the binary display, it is also effective in the case of performing the gradation display, and the present invention is not limited to the case of the binary display .

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating 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 chart showing a method of setting a liquid crystal drive voltage.

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

FIG. 6 is a waveform chart for explaining one of the causes of crosstalk.

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

FIG. 8 is an operation waveform diagram for explaining a problem of the conventional example.

FIG. 9 is an explanatory diagram of a conventional example that does not cause a problem.

FIG. 10 is an operation waveform diagram showing the first embodiment of the present invention.

FIG. 11 is an operation waveform diagram showing a second embodiment of the present invention.

FIG. FIG. 9 is an operation waveform diagram showing a second embodiment of the present invention.
You.

FIG. 13 is an operation waveform diagram showing a third embodiment of the present invention.

FIG. 14 is a circuit diagram showing a specific example of the present invention.

[Explanation of symbols]

 201 control circuit 202 column electrode drive circuit 203 row electrode drive circuit 305 scan signal generation circuit 307 display panel

Claims (4)

(57) [Claims] 1. A possess the column electrode group column electrode driving voltage is applied, the row electrode group row electrode driving voltage is applied based on the scanning selection signal, the row electrode driving voltage, row inversion, row
Every inversion, or k (k = 1, 2,...) Field period
At least the field in each field inversion
The scan selection signal is inverted and row-by-row is not inverted.
At either the leading or trailing edge of each
Each column electrode drive voltage for a fixed time
And one of the voltages corresponding to the dark state.
A fixed time at the leading or trailing edge of the selection period
Each column electrode drive voltage is bright and dark regardless of display data
Liquid crystal display device fixed to the other of the voltages corresponding to the state or
Only the field inversion and the in-line inversion are performed.
Not performed, leading edge of each selection period based on the scan selection signal.
Or each column electrode is driven for a certain time only at the trailing edge of the trailing edge
The voltage corresponds to the bright state and the dark state regardless of the display data
In a liquid crystal display device fixed to one of the voltages, the selection period immediately before or immediately after the field inversion is selected.
Field inversion correction period,
The column electrode driving voltage at the trailing edge is calculated based on display data.
Display state by fixed voltage at the trailing edge of the next selection period
While fixing to the voltage corresponding to the same display state as
The bright display is not visually recognized for the row corresponding to the correction period.
A liquid crystal display device having means. 2. A perforated and column electrode groups column electrode driving voltage is applied, the row electrode group row electrode driving voltage is applied based on the scanning selection signal, the row electrode driving voltage, row inversion, row
Every inversion, or k (k = 1, 2,...) Field period
At least the field in each field inversion
The scan selection signal is inverted and row-by-row is not inverted.
At either the leading or trailing edge of each
Each column electrode drive voltage for a fixed time
And one of the voltages corresponding to the dark state.
A fixed time at the leading or trailing edge of the selection period
Each column electrode drive voltage is bright and dark regardless of display data
Liquid crystal display device fixed to the other of the voltages corresponding to the state or
Only the field inversion and the in-line inversion are performed.
Not performed, leading edge of each selection period based on the scan selection signal.
Or each column electrode is driven for a certain time only at the trailing edge of the trailing edge
The voltage corresponds to the bright state and the dark state regardless of the display data
In a liquid crystal display device fixed to one of the voltages, a field inversion correction period is provided immediately before or immediately after the field inversion, and the column electrode driving voltage at the trailing edge of the field inversion correction period is displayed next. A liquid crystal display characterized by fixing to a voltage corresponding to the same display state as the display state by the fixed voltage at the trailing edge of the selection period of the first row.
Indicating device. 3. possess a column electrode group column electrode driving voltage is applied, the row electrode group row electrode driving voltage is applied based on the scanning selection signal, the row electrode driving voltage, row inversion, row
Every inversion, or k (k = 1, 2,...) Field period
At least the field in each field inversion
Inversion and row-by-row inversion are performed, and each selection is performed based on the scan selection signal.
For a certain period of time at either the leading or trailing edge of the
The pole drive voltage is set to the bright state and the dark state regardless of the display data.
Fixed to one of the applicable voltages and before each selection period.
Driving each column electrode for a certain time at the other edge or trailing edge
The voltage corresponds to the bright state and the dark state regardless of the display data
A liquid crystal display or said field fixed to the other side of the voltage
Only inversion and row-by-line inversion are performed.
The leading or trailing edge of each selection period based on the scan selection signal
The display voltage of each column electrode is displayed for a certain period of time only on the trailing edge.
Irrespective of the data, one of the voltages corresponding to the bright state and the dark state
In a fixed liquid crystal display device , a field inversion correction period is provided immediately before or immediately after the field inversion, and the column electrode drive voltage at the trailing edge of the field inversion correction period is displayed in the first row to be displayed next. liquid, characterized in that for fixing the voltage of the display state according to at fixed voltage to the trailing edge of the selection period corresponding to the opposite display state
Crystal display device. 4. A column electrode group to which a column electrode drive voltage is applied, and a row electrode drive voltage based on a scan selection signal are applied.
Have a row electrode group consisting of an odd number of rows, the row electrode driving electrostatic
Pressure, in-row inversion, row-by-row inversion, or k (k = 1, 2,...)
・) Of the field inversions for each field cycle,
Both perform the field inversion and the line-by-line inversion, and
At the leading or trailing edge of each selection period based on the selection signal.
And the column electrode drive voltage is clear regardless of the display data for a certain period of time.
State and dark state.
At the leading or trailing edge of each selection period.
Each column electrode drive voltage for a fixed time
LCD device fixed to the other of the voltages corresponding to dark and dark conditions
Alternatively, only the field inversion and the line-by-line inversion are performed, and the
The inversion is not performed, and in each selection period based on the scan selection signal,
Each row for a certain time only at the trailing edge of the leading or trailing edge
Electrode drive voltage in bright state and dark state regardless of display data
In a liquid crystal display device which is fixed to one of the corresponding voltages, the selection period immediately before or immediately after the field inversion is set to a certain value.
Field inversion correction period,
The column electrode driving voltage at the trailing edge is calculated based on display data.
Display state by fixed voltage at the trailing edge of the next selection period
It is characterized by fixing to the voltage corresponding to the display state opposite to
Liquid crystal display device.