JP2000194307A - Matrix type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device in which deterioration in a contrast ratio is suppressed to an absolute minimum and lateral direction display irregularities, which are generated immediately before and after a nondisplay interval, are eliminated. SOLUTION: In a matrix type display device, plural row and column electrodes are arranged so as to mutually cross each other and pixels formed at the cross sections of the row and column electrodes are arranged in a matrix manner. All row electrodes have a nondisplay interval having more than one horizontal scanning interval that is not selected. A row electrode driving control means 22 varies the waveforms of the row voltage, that is applied to at least one of the intervals, i.e. among the one horizontal scanning periods immediately before and after the nondisplay interval, against the waveforms of the row voltage of other intervals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a matrix type display device capable of minimizing a decrease in contrast ratio and suppressing occurrence of horizontal display unevenness occurring immediately before and after a non-display period. About.

[0002]

2. Description of the Related Art Matrix display devices are widely used in audiovisual equipment, office automation equipment, game equipment and the like.

[0003] Such a matrix type display device generally includes a display section, a voltage generation circuit, a control circuit, a row electrode drive circuit, and a column electrode drive circuit. The display unit is composed of a plurality of row electrodes and column electrodes arranged in parallel, and is configured to perform display with pixels formed at the intersections of the row electrodes and the column electrodes.

A voltage generation circuit is a circuit that generates a row voltage for driving a row electrode and a column voltage for driving a column electrode. The control circuit is a circuit that outputs a timing control signal that gives a timing for applying the row voltage and the column voltage to the row electrode and the column electrode, respectively. The row electrode drive circuit is a circuit that applies a row voltage to a row electrode in synchronization with a timing control signal. The column electrode drive circuit is a circuit that applies a column voltage to a column electrode in synchronization with a timing control signal.

A typical matrix type display device is a simple matrix type liquid crystal display device. The display section in this simple matrix type liquid crystal display device is a liquid crystal panel having a structure in which liquid crystal is sandwiched between two electrode substrates having row electrodes or column electrodes. Then, display is performed by utilizing the change in the optical characteristics of the liquid crystal due to the application of the row voltage and the column voltage to the liquid crystal panel. Here, a normally black mode in which a non-lighting state is set when the effective voltage applied to the pixel is low, and a lighting state is set when the effective voltage is high, is considered.

In this simple matrix type liquid crystal display device, a row electrode and a column electrode are usually driven by a voltage averaging method, a simultaneous selection driving method for a plurality of rows, or the like. The voltage averaging method is described in, for example, “Latest Technology of Liquid Crystals” p. 106, published by the Industrial Research Council. The multiple row simultaneous selection driving method is, for example,
T. N. See Ruckmongathan, Conf. Re
cord of 1988 Internationala
l Display Research Conference
ence, p. 80 (1988); J. Schef
fer and B. Clifton, 1992 SI
D Digestof Technical Paper
rs XXIII, p. 228 (1992); Ih
ara et al. , 1992 SID Diges
to of Technical Papers XXII
I, p232 (1992).

The voltage averaging method and the plural-row simultaneous selection driving method are based on the following basic principle. That is, the row voltage waveform is represented by an orthogonal matrix such as a unit matrix or a Walsh matrix. The column voltage waveform is obtained by orthogonally transforming the display information using the above-described orthogonal matrix. Then, on the display panel, display is performed by inversely converting this column voltage waveform into display information. According to this basic principle, a constant effective voltage is applied to each pixel in a non-selected row where the matrix element of the orthogonal matrix is equal to 0, regardless of display information, and to each pixel in a selected row other than the non-selected row. An effective voltage based on the display information is applied.

However, in an actual simple matrix type liquid crystal display device, a row voltage waveform is generated due to output impedance in a row electrode driving circuit and a column electrode driving circuit, electrode resistance of a row electrode and a column electrode, and load capacitance such as liquid crystal. In addition, at the changing point of the column voltage waveform, the row voltage waveform and the column voltage waveform are dull or distorted due to induction. For this reason, the effective voltage applied to each pixel deviates from the basic principle, and the deviation of the effective voltage is recognized as display unevenness.

[0009] Of the display irregularities, the following describes the display irregularities occurring in the selected row electrode immediately before and immediately after the non-display period in which all the row electrodes are in the non-selected state. Hereinafter, this display unevenness is referred to as horizontal display unevenness.

According to the basic principle described above, each row electrode is selected for each horizontal scanning period, and each column electrode is provided for each horizontal scanning period in accordance with display information at a pixel at an intersection with the selected row electrode. Column voltage is applied. The display for one screen is 1
This is performed within the vertical scanning period, and the following relationship (1) is established: 1 vertical scanning period = 1 horizontal scanning period × number of row electrodes + non-display period (1). Here, one vertical scanning period is longer than the number of row electrodes in one horizontal scanning period, and a non-display period is provided in a CRT (Cath) typical of a matrix type display device.
This is because a mode ray tube (cathode ray tube) requires a retrace period and maintains compatibility with a CRT in a liquid crystal display device.

According to the basic principle, when the voltage applied to the liquid crystal during the non-display period is 0, the effective voltage ratio between the lighting state and the non-lighting state, which is called the on / off ratio, becomes maximum. Therefore,
In the non-display period of the simple matrix liquid crystal display device, a non-selection voltage is applied to both the row electrodes and the column electrodes. For this reason,
In the column voltage waveform, a change occurs from the column voltage based on the display information to the non-selection voltage immediately before the non-display period, and from the non-selection voltage to the column voltage based on the display information immediately after the non-display period.
As described above, the change point of the voltage waveform is accompanied by a shift of the effective voltage due to dullness or distortion. Since the difference in the effective voltage is different between the non-selected row and the selected row, the brightness of the selected row immediately before and immediately after the non-display period is different from the brightness of the other rows, resulting in horizontal display unevenness.

The display unevenness in the horizontal direction occurs in the selected row immediately before and immediately after the non-display period.
In the case of the multiple-row simultaneous selection driving method, the display unevenness in the horizontal direction is caused by the number of simultaneous selections. As a method for eliminating the horizontal display unevenness, a selective pulse shaving method is disclosed in Japanese Patent Application Laid-Open No. Hei 9-101498.
This selective pulse shaving method will be described below.

FIG. 6 shows a row voltage waveform RW6 and a column voltage waveform CW6 applied to the selected row electrode immediately before the non-display period when the selective pulse shaving method is not employed. In the row voltage waveform RW6 shown in FIG. 6A, as shown by the shaded region R6, the selection voltage SV is changed to the non-selection voltage NV.
Waveform blunting occurs when changing to. In an ideal case without waveform dulling, the selection voltage SV is applied only in one horizontal scanning period T1, and selects only display information in one horizontal scanning period T1. However, if there is waveform blunting, the blunting is applied beyond one horizontal scanning period T1 to the next horizontal scanning period T2, so that display information in the next horizontal scanning period T2 is partially selected. As a result, display information that should be reproduced in the next selected row is reproduced faintly at an incorrect position.

In the selected row immediately before the non-display period, the display information in which the waveform blunting from the selection voltage SV to the non-selection voltage NV is secondarily selected is in a non-display state. In the other row electrodes, the secondary selection becomes display information of the next selected row.

For example, when all the pixels are in the lighting state, in the row electrodes not selected immediately before the non-display period, the display information whose waveform blunting is secondarily selected is all in the lighting state. In the normally black mode, the column voltage indicating the lighting state has a larger voltage difference from the selection voltage SV than the non-selection voltage CNV indicating the non-display state. For example, when the selection voltage SV is positive, the column voltage indicating the lighting state is the column voltage CV62 in FIG. For this reason, in the pixel on the row electrode selected immediately before the non-display period, the effective voltage becomes relatively small due to the secondary selection due to the waveform dulling, and the horizontal display unevenness in which the luminance is reduced occurs. I will.

On the other hand, when all the pixels are in the non-lighting state, in the row electrode not selected immediately before the non-display period, the display information whose waveform dullness is secondarily selected is in the non-lighting state. In the normally black mode, the column voltage indicating the non-lighting state is higher than the non-selection voltage CNV indicating the non-display state by the selection voltage SVV.
The voltage difference from is reduced. For example, when the selection voltage SV is positive, the column voltage indicating the non-lighting state is the column voltage CV in FIG.
It becomes 61. Therefore, in the pixel on the row electrode selected immediately before the non-display period, the effective voltage becomes relatively large due to the secondary selection due to the waveform dulling, and the horizontal display unevenness in which the luminance is increased occurs. I will.

FIG. 7 shows a row voltage waveform RW7 and a column voltage waveform CW7 applied to the selected row electrode immediately after the non-display period when the selective pulse shaving method is not employed.

The column voltage waveform CW7 shown in FIG. 7B changes every horizontal scanning period based on display information. When the column voltage waveform CW7 changes, waveform distortion due to induction occurs in the row electrodes. If the column voltage waveform CW7 changes upward, an upward waveform distortion is also induced in the row electrode, and if it changes downward, a downward waveform distortion is induced. Therefore, if the waveform distortion due to the induction to the row electrode is in the same direction as the selection voltage SV, the effective voltage of the selected row increases, and if the waveform distortion is in the opposite direction, the effective voltage decreases. If the effective voltage shifts, the brightness changes, so
The display unevenness in the horizontal direction occurs according to the waveform distortion caused by the guidance at the time of selection.

In the non-display period, the column electrode is driven by the non-selection voltage CN.
Since V is applied, and immediately after the non-display period, the column voltage waveform CW7 changes from the non-selection voltage CNV to the column voltages CV71 and CV72 according to the display information. In the normally black system, the column voltage CV72 indicating the lighting state has a larger voltage difference from the selection voltage SV than the non-selection voltage CNV indicating the non-display state. Therefore, when all the pixels are in the lighting state, immediately after the non-display period, the column voltage waveform CW7 changes from the non-selection voltage CNV to the column voltage CV72 indicating the lighting state, and in FIG. As shown, waveform distortion is induced in the row electrode in the direction opposite to the selection voltage SV. Therefore, in the pixel on the row electrode selected immediately after the non-display period, the effective voltage decreases and the luminance decreases.

In the normally black mode, the column voltage CV71 indicating the non-lighting state has a smaller voltage difference from the selection voltage SV than the non-selection voltage CNV indicating the non-display state. Therefore, when all the pixels are in the non-lighting state, immediately after the non-display period, the column voltage waveform CW7 changes to the non-selection voltage CNV.
To the column voltage CV71 indicating a non-lighting state, and induces waveform distortion in the same direction as the selection voltage SV on the row electrodes. Therefore, in the pixel on the row electrode selected immediately after the non-display period, the effective voltage increases, and the luminance increases.

FIG. 8 shows a row voltage waveform R applied to a row electrode selected immediately before a non-display period when a selective pulse shaving method is used as a measure against such horizontal display unevenness.
W8 and a column voltage waveform CW8 are shown.

In the row voltage waveform RW8 shown in FIG.
In one horizontal scanning period t0, the non-selection voltage NV is applied during a period t1 immediately after the start and a period t3 immediately before the end, and is switched to the selection voltage SV after a time t1 from the start of the one horizontal scanning period. It is held for a period t2 from the end to a time t3 before.

In a period t3 immediately before the end of one horizontal scanning period, the row voltage waveform RW8 is fixed to the non-selection voltage NV, and the row voltage waveform RW8 includes a dull waveform from the selection voltage SV to the non-selection voltage NV.
It is set within the horizontal scanning period. For this reason, the waveform dulling does not secondarily select the display information in the next one horizontal scanning period, and it is possible to suppress the occurrence of horizontal display unevenness in the selected row immediately before the non-display period.

FIG. 9 shows a row voltage waveform RW9 and a column voltage waveform CW9 applied to the selected row electrode immediately after the non-display period when the selective pulse shaving method is used. As shown in FIG. 9A, the row voltage waveform RW9 is fixed to the non-selection voltage NV in the period t1 immediately after the start of one horizontal scanning period, and therefore, as shown in FIG. Waveform C
W9 is the column voltage C according to the display information from the non-selection voltage CNV.
When the voltage changes to V91 and CV92, it is possible to prevent waveform distortion induced in the row electrodes from being superimposed on the selection voltage SV.
As a result, the waveform distortion is superimposed on the non-selection voltage NV as in the other non-selected rows, so that it is possible to suppress the occurrence of display unevenness in the horizontal direction.

Such a selective pulse shaving method, for example,
This is realized by the following configuration.

FIG. 10 shows a latch pulse LP output from the control circuit and a row voltage output control signal RS output from the row electrode drive control means and the column electrode drive control means in the control circuit.
10 and a column voltage output control signal CS10. Here, the latch pulse LP shown in FIG. 10A is the same as the horizontal synchronization signal, and the period from the latch pulse LP to the next latch pulse LP is one horizontal scanning period. The row electrode drive circuit applies a selection voltage SV or a non-selection voltage NV to each row electrode based on an orthogonal function in synchronization with the latch pulse LP.
Is applied. In addition, the column electrode driving circuit outputs the latch pulse L
In synchronization with P, a column voltage C based on the operation output is applied to each column electrode.
V is applied.

Further, the row electrode driving circuit and the column electrode driving circuit respectively perform a row voltage output control signal RS10 and a row voltage output control signal RS10 shown in FIG. 10B, irrespective of the output operation synchronized with the latch pulse LP. Column voltage output control signal CS shown in FIG.
10 allows the output voltages to be the non-selection voltages NV and CNV. Here, the row voltage output control signal RS10
Is low level, the output of the row electrode drive circuit is the non-selection voltage NV, and the column voltage output control signal CS10 is low.
When at the w level, the output of the column electrode drive circuit is the non-selection voltage CNV.

In FIG. 10, a non-display period is a period in which the row voltage output control signal RS10 and the column voltage output control signal CS10 are at a Low level over one horizontal scanning period or more.
Non-selection voltages NV and CNV are applied to the row electrodes and the column electrodes. The row voltage output control signal R shown in FIG.
S10 is at the Low level in the first half period t1 and the second half period t3 of one horizontal scanning period, and is shown in FIGS.
Can be realized.

[0029]

When the above-described selective pulse shaving method is employed, the on / off ratio is reduced, so that the luminance ratio (contrast ratio) between the lit state and the non-lit state is reduced.
In the time chart shown in FIG. 10, the on / off ratio decreases as the application period (t2 / t0) of the selection voltage SV in one horizontal scanning period decreases. In particular, in a liquid crystal panel with a large screen, high definition, and high-speed response, the contrast ratio is significantly reduced. Because
If the liquid crystal capacity increases due to a large screen and a narrow cell gap for high-speed response, the dullness and the distortion due to induction increase, and the necessary pulse shaving widths t1 and t3 increase. This is because the width t0 of one horizontal scanning period becomes short in high-frequency driving or the like aiming at high-speed response.

Therefore, in a liquid crystal panel having a large screen, high definition, and high-speed response, it is difficult to sufficiently secure the selection pulse cutting widths t1 and t3 in the selection pulse cutting method due to a decrease in contrast ratio.

The present invention solves the above-mentioned problems of the prior art, in which a decrease in contrast ratio can be minimized, and the occurrence of horizontal display unevenness occurring immediately before and immediately after the above-described non-display period. It is an object of the present invention to provide a matrix-type display device capable of suppressing the occurrence of an image.

[0032]

According to the present invention, a plurality of row electrodes and a plurality of column electrodes are arranged so as to intersect with each other, and pixels formed at intersections of the row electrodes and the column electrodes are arranged in a matrix. A matrix-type display device having a non-display period of at least one horizontal scanning period in which all the row electrodes are not selected, one horizontal scanning period immediately before the non-display period, and the non-display period. The waveform of the row voltage applied in at least one of the one horizontal scanning period immediately after
A row electrode drive control means for changing the waveform of the row voltage in other periods is provided, thereby achieving the above object.

Preferably, the row voltage comprises a selection voltage for selecting the row electrode and a non-selection voltage not selecting the row electrode, and a predetermined period of one horizontal scanning period in the waveform of the row voltage is A matrix-type display device fixed to the non-selection voltage, wherein the voltage is applied to at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. A configuration is provided that includes selection voltage control means for changing the application time width of the selection voltage with respect to other periods.

Preferably, the row voltage comprises a selection voltage for selecting the row electrode, a non-selection voltage that does not select the row electrode, and a correction voltage. A horizontal scanning period and one immediately after the non-display period.
A configuration is provided that includes a correction voltage control unit that changes an application time width of the correction voltage applied in at least one of the horizontal scanning periods with respect to other periods.

Preferably, the row electrode drive control means is applied during at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. There is provided a means for changing the waveform of the row voltage with respect to the waveform of the row voltage in other periods in accordance with display information.

Further, according to the present invention, a plurality of row electrodes and a plurality of column electrodes are arranged so as to intersect with each other, and pixels formed at intersections between the row electrodes and the column electrodes are arranged in a matrix. A non-display period of at least one horizontal scanning period in which all the row electrodes are not selected, one horizontal scanning period immediately before the non-display period, and one horizontal scanning period immediately after the non-display period. Column electrode drive control means for changing the waveform of the column voltage applied in at least one of the horizontal scanning periods with respect to the waveform of the column voltage in other periods, thereby achieving the above object. Is done.

Preferably, the column electrode drive control means includes:
The column voltage waveform applied in at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period is changed to a column voltage waveform in another period. On the other hand, it has a means for changing according to the display information.

Further, according to the present invention, a plurality of row electrodes and a plurality of column electrodes are arranged so as to intersect with each other, and pixels formed at intersections between the row electrodes and the column electrodes are arranged in a matrix. A non-display period of at least one horizontal scanning period in which all the row electrodes are not selected, and the first one horizontal scanning period of the non-display period or the first half of the one horizontal scanning period. The section has first column voltage control means for applying a column voltage corresponding to a column voltage in one horizontal scanning period immediately before the non-display period, thereby achieving the above object.

Preferably, the first column voltage control means applies the same column voltage as the column voltage in one horizontal scanning period immediately before the non-display period.

Further, according to the present invention, a plurality of row electrodes and a plurality of column electrodes are arranged so as to intersect each other, and pixels formed at intersections of the row electrodes and the column electrodes are arranged in a matrix. A non-display period of at least one horizontal scanning period in which all the row electrodes are not selected, and the last one horizontal scanning period of the non-display period or the latter half of the one horizontal scanning period. The section has second column voltage control means for applying a column voltage corresponding to the column voltage in one horizontal scanning period immediately after the non-display period, thereby achieving the above object.

Preferably, the second column voltage control means applies the same column voltage as the column voltage in one horizontal scanning period immediately after the non-display period.

The operation of the present invention will be described below.

In the matrix type display device of the present invention, a plurality of row electrodes and a plurality of column electrodes are arranged so as to intersect with each other, and pixels formed at intersections between the row electrodes and the column electrodes are arranged in a matrix. Be done. Row electrode is one for display
A column voltage is selected by applying a row voltage every horizontal scanning period, and a column electrode is applied with a column voltage according to display information of a pixel on the selected row electrode every one horizontal scanning period. The display is performed based on the difference between.

In an actual simple matrix type liquid crystal display device, the row voltage waveform and the column voltage depend on the output impedance of the row electrode driving circuit and the column electrode driving circuit, the electrode resistance of the row and column electrodes, and the load capacitance of the liquid crystal and the like. At the changing point of the voltage waveform, the row voltage waveform and the column voltage waveform are dull or distorted due to induction. For this reason, the effective voltage applied to each pixel deviates from the basic principle, and this deviation is recognized as display unevenness.

If the waveform blunting from the selection voltage to the non-selection voltage extends over the next horizontal scanning period, the waveform blunting component will secondarily select the display information in the next horizontal scanning period. For example, in the case of the full-screen lighting state, the display information in which the waveform blunting from the selected voltage to the non-selection voltage is secondarily selected is a non-display state only immediately before the non-display period, and the other than the light-on state. Become. As a result, in the row electrode selected immediately before the non-display period, the effective voltage is relatively reduced, and low-luminance horizontal display unevenness occurs.

At the transition point from the non-display period to the display period, the column voltage waveform changes from the non-selection voltage to the column voltage according to the display information, and the column voltage waveform becomes dull or the waveform is induced by the row electrodes. Distortion occurs. The influence of the waveform distortion due to the column voltage waveform dulling and the induction to the row electrode is different between the selected row immediately after the non-display period and the other rows. Unlike the rows, the display becomes uneven in the horizontal direction.

Therefore, the row electrode drive control means changes the waveform of the row voltage applied in at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. By changing the waveform of the row voltage in other periods, it is possible to suppress the occurrence of horizontal display unevenness that occurs in the selected row immediately before and immediately after the non-display period.

The row voltage comprises a selection voltage for selecting a row electrode and a non-selection voltage for selecting no row electrode, and a predetermined period of one horizontal scanning period in the waveform of the row voltage is fixed to the non-selection voltage. In the matrix type display device, the selection voltage control means applies the selection voltage applied to at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. Is changed with respect to other periods. As a result, it is possible to easily adjust the deviation of the effective voltage generated in the selected row immediately before and immediately after the non-display period, and it is possible to suppress the occurrence of horizontal display unevenness.

In the case where the row voltage comprises a selection voltage for selecting a row electrode, a non-selection voltage for not selecting a row electrode, and a correction voltage, the correction voltage control means sets the correction voltage immediately before the non-display period. The application time width of the correction voltage applied in at least one of one horizontal scanning period and one horizontal scanning period immediately after the non-display period is changed with respect to other periods. As a result, it is possible to easily adjust the deviation of the effective voltage generated in the selected row immediately before and immediately after the non-display period, and it is possible to suppress the occurrence of horizontal display unevenness. In this case, a circuit for generating the correction voltage is required as compared with the method of changing the application time width of the selection voltage and the non-selection voltage, but fine adjustment is easy because the voltage for changing the time width is small. Become.

For example, in the case of the full-screen lighting state, as described above, the effective voltage is relatively reduced in the row electrode selected immediately before the non-display period, and low-luminance horizontal display unevenness occurs. Will happen. On the other hand, when the full screen is off,
The display information in which the waveform dulling from the selected voltage to the non-selected voltage is secondarily selected is in a non-display state only immediately before the non-display period, and is in a non-lighting state in other cases. Therefore, in the full screen non-lighting state, in the row electrode selected immediately before the non-display period, the effective voltage relatively rises, and high-luminance horizontal display unevenness occurs.

Immediately after the non-display period, the column voltage waveform changes from the non-selection voltage to the column voltage according to the display information, so that the row electrodes are distorted by induction. In the case of the full-screen lighting state, the waveform distortion is in the opposite direction to the selection voltage applied to the selected row immediately after the non-display period, and the luminance of the selected row decreases. On the other hand, in the full screen non-lighting state, the waveform distortion is in the same direction as the selection voltage applied to the selected row immediately after the non-display period, and the luminance of the selected row increases.

Therefore, the row electrode drive control means allows
The waveform of the row voltage applied in at least one of one horizontal scanning period immediately before the non-display period and the one horizontal scanning period immediately after the non-display period is compared with the waveform of the row voltage in the other periods. With a configuration that changes according to the display information,
The correction of the effective voltage according to the display information becomes possible, and it becomes possible to suppress the occurrence of display unevenness in the horizontal direction without depending on the display information.

In addition, the column electrode drive control means controls the waveform of the column voltage applied in at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. , The waveform of the column voltage in other periods. This makes it possible to suppress the occurrence of display unevenness in the horizontal direction that occurs in the selected row immediately before and immediately after the non-display period.

As described above, the deviation of the effective voltage of the display unevenness in the horizontal direction depends on the display information. Therefore, the column electrode drive control means changes the waveform of the column voltage applied in at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. By changing the column voltage waveform during the period according to the display information, it is possible to suppress the occurrence of display unevenness in the horizontal direction regardless of the display information.

In the first one horizontal scanning period of the non-display period, the first column voltage control means applies a column voltage corresponding to the column voltage in one horizontal scanning period immediately before the non-display period. This makes it possible to control the change in the column voltage waveform due to the change from the display period to the non-display period, so that it is possible to suppress the occurrence of horizontal display unevenness that occurs in the selected row immediately before the non-display period. Becomes

Further, the first column voltage control means applies a column voltage corresponding to the column voltage in one horizontal scanning period immediately before the non-display period in the first half of the first horizontal scanning period in the non-display period. . This makes it possible to control the change in the column voltage waveform at the transition point from the display period to the non-display period, thereby suppressing the occurrence of horizontal display unevenness that occurs in the selected row immediately before the non-display period. Becomes In addition, the time width of the column voltage applied during the non-display period can be minimized, and the decrease in the contrast ratio due to the decrease in the on / off ratio can be minimized.

Further, the first column voltage control means applies the same column voltage as the column voltage in one horizontal scanning period immediately before the non-display period. As a result, the position of the change point of the column voltage waveform accompanying the change from the display period to the non-display period can be shifted toward the non-display period by one horizontal scanning period.
It is possible to suppress the occurrence of horizontal display unevenness that occurs in the selected row immediately before the non-display period.

Further, by applying the same column voltage as the column voltage in one horizontal scanning period immediately before the non-display period to the first half of the first one horizontal scanning period in the non-display period, Since the position of the change point of the column voltage waveform due to the change to the non-display period can be shifted, it is possible to suppress the occurrence of horizontal display unevenness that occurs in the selected row immediately before the non-display period. In addition, the time width of the column voltage applied during the non-display period can be minimized, and the decrease in the contrast ratio due to the decrease in the on / off ratio can be minimized.

Further, in the last one horizontal scanning period of the non-display period, the second column voltage control means applies a column voltage corresponding to the column voltage in one horizontal scanning period immediately after the non-display period. This makes it possible to control the change in the column voltage waveform due to the change from the non-display period to the display period, thereby suppressing horizontal display unevenness occurring in the selected row immediately after the non-display period. Becomes

Further, the second column voltage control means applies a column voltage corresponding to the column voltage in one horizontal scanning period immediately after the non-display period in the latter half of the last one horizontal scanning period in the non-display period. . This makes it possible to control the change in the column voltage waveform due to the change from the non-display period to the display period, thereby suppressing horizontal display unevenness occurring in the selected row immediately after the non-display period. Becomes In addition, the time width of the column voltage applied during the non-display period can be minimized, and the decrease in the contrast ratio due to the decrease in the on / off ratio can be minimized.

Further, the second column voltage control means applies the same column voltage as the column voltage in one horizontal scanning period immediately after the non-display period. As a result, the change in the column voltage waveform at the transition point from the non-display period to the display period can be shifted toward the non-display period by one horizontal scanning period. It is possible to suppress display unevenness.

Further, by applying the same column voltage as the column voltage in one horizontal scanning period immediately after the non-display period to the latter half of the last one horizontal scanning period in the non-display period, Since the position of the point of change of the column voltage waveform due to the change to the non-display period can be controlled, it is possible to suppress the occurrence of horizontal display unevenness that occurs in the selected row immediately after the non-display period. In addition, the time width of the column voltage CV applied during the non-display period can be minimized, and the decrease in the contrast ratio due to the decrease in the on / off ratio can be minimized.

[0063]

Embodiments of the present invention will be specifically described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows a matrix type display device according to Embodiment 1 of the present invention.

In this matrix type display device, a plurality of row electrodes and a plurality of column electrodes are arranged so as to intersect each other.
A matrix display device in which pixels formed at intersections of row electrodes and column electrodes are arranged in a matrix,
A non-display period equal to or longer than one horizontal scanning period in which all the row electrodes are not selected, and at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period As shown in FIG. 1, the control circuit 8 has a row electrode drive control means 22 for changing the waveform of the row voltage applied to the row voltage to the waveform of the row voltage in other periods.

Also, in this matrix type display device, the row voltage is composed of a selection voltage for selecting a row electrode and a non-selection voltage for not selecting a row electrode. A matrix display device in which a period is fixed to a non-selection voltage, wherein the voltage is applied to at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. As shown in FIG. 1B, a selection voltage control means 23 for changing the application time width of the selected voltage with respect to other periods can be provided in the row electrode drive control means 22.

The row electrode drive control means 22 controls the row voltage applied during at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. It is also possible to adopt a configuration having means 25 for changing the waveform with respect to the waveform of the row voltage in other periods according to the display information.

More specifically, this matrix type display device is a simple matrix type liquid crystal display device, as shown in FIG.
As shown in FIG. 1A, a liquid crystal panel 1, a row electrode driving circuit 2, a column electrode driving circuit 3, a memory 4, an arithmetic circuit 5, a function generator 6, a voltage generating circuit 7, and a control circuit 8 are provided.

The liquid crystal panel 1 has a plurality of row electrodes 11 arranged in parallel in the row direction and a plurality of column electrodes 12 arranged in parallel in the column direction. Row electrode 11
The column electrodes 12 are arranged so as to be orthogonal to each other with a liquid crystal layer (not shown) interposed therebetween. A pixel is formed at each intersection between the row electrode 11 and the column electrode 12. Each row electrode 11 is connected to a row electrode drive circuit 2, and each column electrode 12 is connected to a column electrode drive circuit 3.

The memory 4 is a storage device for temporarily storing input display information, and is, for example, a frame memory. Note that the memory 4 may be omitted. The arithmetic circuit 5 is a circuit for orthogonally transforming the display information from the memory 4 using the orthogonal function generated by the function generator 6. The function generator 6 is a circuit that generates and outputs an orthogonal function represented by a unit matrix, a Walsh matrix, or the like.

The voltage generation circuit 7 includes a row electrode driving selection voltage SV and a non-selection voltage NV output to the row electrode driving circuit 2.
, And a column electrode driving column voltage CV and a non-selection voltage CNV output to the column electrode driving circuit 3 are generated. The row electrode drive circuit 2 generates a row voltage output from the voltage generation circuit 7 based on the orthogonal function generated by the function generator 6, the latch pulse LP given from the control circuit 8, and the row voltage output control signal RS. This circuit applies a selection voltage SV and a non-selection voltage NV to each row electrode 11. The column electrode driving circuit 3 outputs the column voltage CV output from the voltage generation circuit 7.
Is selected based on the operation output of the operation circuit 5, and the control circuit 8
Is a circuit applied to each column electrode 12 in accordance with a latch pulse LP given from the column and a column voltage output control signal CS.

FIG. 2 shows the relationship among the latch pulse LP, the row voltage output control signal RS2, and the column voltage output control signal CS2 in the matrix type display device according to the first embodiment of the present invention. Here, the row voltage output control signal RS2 is generated by the selection voltage control means 23. The latch pulse LP shown in FIG. 2A is the same as the horizontal synchronization signal, and the period from the latch pulse LP to the next latch pulse LP is one horizontal scanning period. The row electrode driving circuit 2 outputs the latch pulse L
In synchronization with P, a selection voltage SV or a non-selection voltage NV is applied to each row electrode 11 based on an orthogonal function. Further, the column electrode drive circuit 3 applies a column voltage CV to each column electrode 12 based on a calculation output in synchronization with the latch pulse LP.

Further, the row electrode drive circuit 2 and the column electrode drive circuit 3 respectively control the row voltage output control signal RS2 shown in FIG. 2B and the row voltage output control signal RS2 shown in FIG. The output voltage can be set to the non-selection voltages NV and CNV by the column voltage output control signal CS2 shown in c). Here, the row voltage output control signal RS2 is Low.
When the level is at the level, the output of the row electrode drive circuit 2 is the non-selection voltage NV. When the column voltage output control signal CS2 is at the low level, the output of the column electrode drive circuit 3 is at the non-selection voltage CNV.
It is.

In FIG. 2, the row voltage output control signal RS2 and the column voltage output control signal C over one horizontal scanning period or longer.
A period in which S2 is at the Low level is a non-display period, and non-selection voltages NV and CNV are applied to each row electrode 11 and column electrode 12. The row voltage output control signal R shown in FIG.
Except for the horizontal scanning period immediately before and immediately after the non-display period, S2 is the first half period t1 of one horizontal scanning period as in FIG.
In the period t3 in the second half, the signal is at the Low level, and the selective pulse cutting method as shown in FIGS. 8 and 9 is realized.

However, in the row voltage output control signal RS2 shown in FIG. 2B, the Low level period in one horizontal scanning period immediately before and immediately after the non-display period is different from the other horizontal scanning periods. Is different. In FIG. 2B, the Low level period in one horizontal scanning period immediately before the non-display period is (t0-t4), and immediately after the non-display period is (t0-t5). In the scanning period, it is (t0-t2).

If the selection pulse shaving widths t1 and t3 are not sufficient, as described above, in the full screen lighting state, the brightness of the selected row immediately before and immediately after the non-display period is lower than that of the other row electrodes. Therefore, in one horizontal scanning period immediately before and immediately after the non-display period, the period during which the row voltage output control signal RS2 shown in FIG. By increasing the application period of the selection voltage SV from t2 to t4 and t5, it is possible to compensate for a decrease in luminance.

In the full screen non-lighting state, the luminance in the selected row immediately before and immediately after the non-display period is higher than in the other row electrodes. Therefore, in one horizontal scanning period immediately before and immediately after the non-display period, the period during which the row voltage output control signal RS2 shown in FIG. Can be suppressed. As described above, the means 25 for changing the row voltage waveform in accordance with the display information allows the low level period of the row voltage output control signal RS2 in one horizontal scanning period immediately before and immediately after the non-display period in accordance with the display information. , The horizontal display unevenness can be effectively suppressed.

More specifically, for example, the number of latch pulses LP is counted by a counter to specify the horizontal scanning period immediately before and immediately after the non-display period, and the number of illuminated pixels on each row electrode is counted by the counter. This can be realized by the selection voltage control unit 23 that makes the Low level period of the row voltage output control signal RS2 variable according to the number of pixels, and the unit 25 that changes the row voltage waveform according to display information.

(Embodiment 2) The matrix type display device according to Embodiment 2 of the present invention has the basic configuration of the simple matrix type liquid crystal display device shown in FIG. 1, as in Embodiment 1 described above.

In this matrix type display device, the row voltage is
It consists of a selection voltage for selecting a row electrode, a non-selection voltage that does not select a row electrode, and a correction voltage, and includes one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. As shown in FIG. 1, the row electrode drive control unit 22 includes a correction voltage control unit 24 that changes the application time width of the correction voltage applied in at least one of the periods with respect to the other periods. .

The row electrode drive control means 22 controls one horizontal scanning period immediately before the non-display period and one horizontal scan period immediately after the non-display period.
It is also possible to adopt a configuration having means 25 for changing the waveform of the row voltage applied in at least one of the horizontal scanning periods with respect to the waveform of the row voltage in other periods in accordance with display information.

More specifically, in the second embodiment, the voltage generation circuit 7 uses the selection voltage SV and the non-selection voltage NV in the first embodiment as the row electrode driving row voltage output to the row electrode drive circuit 2. , And generates a correction voltage CMV.
The control circuit 8 outputs a correction voltage output control signal VC from the correction voltage control means 24 together with the same latch pulse LP and row voltage output control signal RS3 as in FIG.

The row electrode drive circuit 2 switches the voltage applied to each row electrode 11 between a selected row and a non-selected row based on an orthogonal function in synchronization with the latch pulse LP. The non-selection row is applied with the non-selection voltage NV, and the selection row is applied with the selection voltage SV, the correction voltage CMV, and the non-selection voltage NV.

As a specific example, FIG. 3 shows a latch pulse L in the matrix type display device according to the second embodiment of the present invention.
P, row voltage output control signal RS3, column voltage output control signal C
S3, a correction voltage output control signal VC, a row voltage waveform RW2 selected in the horizontal scanning period immediately before the non-display period, and a row voltage waveform RW1 selected in the immediately preceding horizontal scanning period
Shows the relationship.

As in the case of the first embodiment, when the row voltage output control signal RS3 shown in FIG. 3B is at the low level, the row electrode drive circuit 2 outputs the non-selection voltage NV to the row electrodes. Further, when the row voltage output control signal RS3 shown in FIG.
The correction voltage CMV is output to the selected row according to the level of the correction voltage output control signal VC shown in FIG. Here, as shown in FIGS. 3E and 3F, the row electrode drive circuit 2 outputs the selection voltage SV to the selected row when the correction voltage output control signal VC is at the Low level, and outputs the selection voltage SV when the correction voltage output control signal VC is at the High level. The correction voltage CMV having a higher peak value than the selection voltage SV
Is output.

The row voltage output control signal RS shown in FIG.
FIG. 3 shows a horizontal scanning period immediately before and immediately after a non-display period which is at a low level over one horizontal scanning period.
The High level period of the correction voltage output control signal VC shown in (d) is different from other horizontal scanning periods. FIG.
As shown in (d), the High level period of the correction voltage output control signal VC in one horizontal scanning period immediately before the non-display period is t7, and immediately after the non-display period is t8. It is t6 in the scanning period.

For example, in the full screen lighting state, the brightness on the row electrode selected immediately before and immediately after the non-display period becomes lower than the others. Therefore, the correction voltage output control signal V shown in FIG. 3D in one horizontal scanning period immediately before and immediately after the non-display period.
The high-level periods t7 and t8 of C are changed to another period t6.
By making the length longer than that, it is possible to increase the effective value of the pixel on the row electrode selected immediately before and immediately after the non-display period, and to compensate for a decrease in luminance.

In the full screen non-lighting state, the brightness of the pixel on the row electrode selected immediately before and immediately after the non-display period is higher than the others. Accordingly, by setting the high-level periods t7 and t8 of the correction voltage output control signal VC shown in FIG. 3D in one horizontal scanning period immediately before and immediately after the non-display period to be shorter than the other periods t6, The effective value of the pixel on the row electrode selected immediately before or immediately after the display period can be reduced, and the increase in luminance can be suppressed.

As described above, the means 25 for changing the row voltage waveform according to the display information allows the correction voltage output control signal VC to be changed to the high level during one horizontal scanning period immediately before and immediately after the non-display period according to the display information. By controlling the level period, the occurrence of display unevenness in the horizontal direction can be suppressed.
Japanese Patent Application Laid-Open No. 10-11670 discloses a method in which a correction voltage is applied to a row electrode to suppress display unevenness caused by a difference in waveform dullness of a row voltage between a lighting state and a non-lighting state. Therefore, the detailed description is omitted here, but the method of the present invention can be used together with this method.

In the matrix type display device according to the present invention, a plurality of row electrodes and a plurality of column electrodes are arranged so as to intersect with each other, and pixels formed at intersections of the row electrodes and the column electrodes are arranged in a matrix. A non-display period that is not less than one horizontal scanning period in which all the row electrodes are not selected, and one horizontal scanning period immediately before the non-display period, and a non-display period. The column electrode drive control means 26 which changes the waveform of the column voltage applied in at least one of the subsequent one horizontal scanning periods to the waveform of the column voltage in the other period is controlled as shown in FIG. The structure included in the circuit 8 can be employed.

As shown in FIG. 1B, the column electrode drive control means 26 controls at least one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. It is also possible to adopt a configuration having means 29 for changing the waveform of the column voltage applied in one period to the waveform of the column voltage in the other period in accordance with display information.

The specific configuration of the column electrode drive control means 26 can be realized in the same manner as the row electrode drive control means 22 of the first and second embodiments, for example, by applying a correction voltage to the column voltage. Detailed description is omitted. The column electrode drive control means 26 of this configuration can also eliminate horizontal display unevenness.

(Embodiment 3) The matrix type display device according to Embodiment 3 of the present invention has the basic configuration of the simple matrix type liquid crystal display device shown in FIG. 1 as in Embodiment 1 described above.

In this matrix type display device, a plurality of row electrodes and a plurality of column electrodes are arranged so as to cross each other.
A matrix display device in which pixels formed at intersections of row electrodes and column electrodes are arranged in a matrix,
A non-display period equal to or longer than one horizontal scanning period in which all row electrodes are not selected. In the first one horizontal scanning period of the non-display period, the column voltage applied in one horizontal scanning period immediately before the non-display period is reduced. A first column voltage control unit 27 for applying a corresponding column voltage is replaced with a column electrode drive control unit 26 as shown in FIG.
Have in.

Further, this matrix type display device has a non-display period of one horizontal scanning period or more in which all the row electrodes are not selected. In the last one horizontal scanning period of the non-display period, immediately after the non-display period The second column voltage control means 28 for applying a column voltage according to the column voltage applied in one horizontal scanning period is provided in the column electrode drive control means 26 as shown in FIG.

Further, the first column voltage control means 27
It is also possible to adopt a configuration in which the same column voltage as the column voltage in one horizontal scanning period immediately before the non-display period is applied.

Further, the second column voltage control means 28
A configuration in which the same column voltage as the column voltage in one horizontal scanning period immediately after the non-display period may be applied.

As a specific example, FIG. 4 shows a latch pulse L in a matrix type display device according to Embodiment 3 of the present invention.
The relation between P, the row voltage output control signal RS4, and the column voltage output control signal CS4 is shown. The column voltage output control signal CS4 is
First column voltage control means 27 and second column voltage control means 28
Generated by the column electrode drive control means 26. Here, the row voltage output control signal RS4 shown in FIG.
A period in which the signal is at the Low level over one horizontal scanning period is a non-display period. In the third embodiment, unlike the conventional example shown in FIG. 10, as shown in FIG. 4C, the column voltage output control signal CS4 in the first and last one horizontal scanning period of the non-display period is at a low level. is not.

By controlling the value of the column voltage CV during the first and last one horizontal scanning period of the non-display period, a change in the column voltage waveform caused when the display period changes to the non-display period and the non-display period changes to the display period. Can be controlled. Therefore, it is possible to eliminate display unevenness caused by waveform dulling and distortion due to induction caused by a change in column voltage waveform occurring immediately before and immediately after the non-display period.

This is because an operation output such that a desired column voltage waveform can be obtained at the beginning and end of the display period is supplied to the column electrode driving circuit 3.
, And applied to each column electrode 12 in synchronization with the latch pulse LP as in the case of normal display information.

In particular, as one effective method, the value of the column voltage CV in the first and last one horizontal scanning period of the non-display period is changed to the value of the column voltage CV in the immediately preceding and succeeding one horizontal scanning period, respectively. There is a method of making the same.

Conventionally, as shown in FIG. 10, in the non-display period, the arithmetic circuit 5 does not output the operation result to the column electrode driving circuit 3, and the column electrode driving circuit 3 operates in the last one horizontal scanning period of the display period. And the non-selection voltage CNV is applied to each column electrode 12 based on the column voltage output control signal CS10 shown in FIG.

On the other hand, in the third embodiment, FIG.
As shown in (c), by setting the column voltage output control signal CS4 to the High level in the first one horizontal scanning period of the non-display period, the same as the column voltage CV in the last one horizontal scanning period of the display period. The column voltage CV is applied to each column electrode 12.
Can be applied.

Further, the calculation result in the first one horizontal scanning period of the display period is previously stored in the column electrode driving circuit 3 in the non-display period.
In the last one horizontal scanning period of the non-display period,
The column voltage output control signal CS4 shown in FIG.
By setting the level, the same column voltage CV as the column voltage CV in the first horizontal scanning period of the display period can be applied to each column electrode 12.

As described above, the values of the column voltage CV in the first and last one horizontal scanning period of the non-display period are respectively
By making the column voltage CV equal to the value of the column voltage in one horizontal scanning period immediately before and after that, a change in the column voltage waveform does not occur when changing from the display period to the non-display period and from the non-display period to the display period. Therefore, since the column voltage waveform does not change at the start and end of the non-display period, it is possible to eliminate the horizontal display unevenness caused by the dullness and the distortion due to the change in the column voltage waveform.

(Embodiment 4) In the above-described Embodiment 3, the change in the column voltage waveform that has occurred at the time of change from the non-display period to the display period or from the display period to the non-display period is changed by one horizontal scanning period. An example in which the influence of the column voltage waveform change is eliminated by shifting the column voltage waveform forward or backward by one horizontal scanning period has been described. However, the present invention is not limited to this. The width may be a period other than one horizontal scanning period. In general, when a column voltage is applied during the non-display period, the contrast ratio decreases due to a decrease in the on / off ratio. Therefore, it is desirable that the shift width of the column voltage waveform change point be the minimum required period.

That is, the matrix type display device according to the fourth embodiment of the present invention has the basic configuration of the simple matrix type liquid crystal display device shown in FIG. 1 as in the first embodiment, and all the row electrodes are not selected. It has a non-display period of one horizontal scanning period or more, and as shown in FIG. 1B, in the first half of the first one horizontal scanning period of the non-display period, in one horizontal scanning period immediately before the non-display period. It has a first column voltage control means 27 for applying a column voltage according to the column voltage.

Further, this matrix type display device has a non-display period of one horizontal scanning period or more in which all the row electrodes are not selected, and as shown in FIG. 1B, the last one of the non-display periods. In the latter half of the horizontal scanning period, there is provided second column voltage control means 28 for applying a column voltage corresponding to the column voltage in one horizontal scanning period immediately after the non-display period.

Further, the first column voltage control means 27
It is also possible to adopt a configuration in which the same column voltage as the column voltage in one horizontal scanning period immediately before the non-display period is applied.

Further, the second column voltage control means 28
A configuration in which the same column voltage as the column voltage in one horizontal scanning period immediately after the non-display period may be applied.

As a specific example, FIG. 5 shows a latch pulse LP, a row voltage output control signal RS5, and a column voltage output control signal CS5 in the matrix type display device according to the fourth embodiment.
Shows the relationship.

According to the column voltage output control signal CS4 of the third embodiment shown in FIG.
Although the high level is set during the horizontal scanning period, in the fourth embodiment, as shown in FIG. 5C, the column voltage output control signal CS5 is set between the period from the start of the non-display period to the period t9, and
The high level is during a period t10 before the end of the non-display period. Therefore, the column voltage waveform changes from the value of the column voltage CV corresponding to the display information to the non-selection voltage CNV after the period t9 from the start of the non-display period, and the column voltage waveform becomes non-selection voltage before the period t10 from the end of the non-display period. The voltage changes from the selection voltage CNV to the value of the column voltage CV according to the display information.

That is, the change in the column voltage waveform that has occurred when changing from the non-display period to the display period is shifted to before the period t10, or the change in the column voltage waveform that occurs when changing from the display period to the non-display period. Is shifted toward the end of the period t9, thereby eliminating the influence of the column voltage waveform change on the display.

Therefore, according to the fourth embodiment, the column voltage CV during the non-display period is different from that of the third embodiment shown in FIG.
Can be shortened, and the display unevenness in the horizontal direction can be suppressed while the decrease in the contrast ratio is minimized.

In the above, in order to simplify and explain the problem, the cause of the display unevenness in the horizontal direction has been described based on the dullness of the row voltage waveform and the distortion caused by the induction, with reference to FIGS. 6 and 7. In addition, other factors such as the dulling of the column voltage waveform are involved.
For this reason, the brightness of the display unevenness in the horizontal direction is not necessarily low in the fully lit state, and is not necessarily high in the completely unlit state, but in any case, by applying the means of the present invention. In addition, it is possible to suppress the occurrence of display unevenness in the horizontal direction.

[0116]

As described above, according to the matrix type display device of the present invention, it is possible to suppress the occurrence of horizontal display unevenness occurring in the pixels on the row electrodes selected immediately before and immediately after the non-display period. And a reduction in contrast ratio can be minimized.

More specifically, the row electrode drive control means controls the row voltage applied during at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. By changing the waveform with respect to the waveform of the row voltage in other periods, it is possible to suppress the occurrence of horizontal display unevenness that occurs in the selected row immediately before and immediately after the non-display period.

The row voltage is composed of a selection voltage for selecting a row electrode and a non-selection voltage that does not select a row electrode, and a predetermined period of one horizontal scanning period in the waveform of the row voltage is fixed to the non-selection voltage. In the matrix type display device, the selection voltage control means applies the selection voltage applied to at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. When the configuration is such that the application time width is changed with respect to the other periods, it is possible to easily adjust the deviation of the effective voltage that occurs in the selected row immediately before and immediately after the non-display period. Can be suppressed.

When the row voltage is composed of a selection voltage for selecting a row electrode, a non-selection voltage for not selecting a row electrode, and a correction voltage, the correction voltage control means sets the correction voltage immediately before the non-display period. When the application time width of the correction voltage applied in at least one of one horizontal scanning period and one horizontal scanning period immediately after the non-display period is changed with respect to the other periods, non-display can be easily performed. Since the deviation of the effective voltage in the selected row immediately before and after the period can be adjusted, it is possible to suppress the occurrence of display unevenness in the horizontal direction.
In this case, a circuit for generating the correction voltage is required as compared with the method of changing the application time width of the selection voltage and the non-selection voltage, but fine adjustment is easy because the voltage for changing the time width is small. Become.

The row electrode drive control means changes the waveform of the row voltage applied in at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. In addition, when the configuration is such that the waveform of the row voltage in other periods is changed in accordance with the display information, the effective voltage can be corrected in accordance with the display information, and the display unevenness in the horizontal direction is generated independently of the display information. Can be suppressed.

Further, the column electrode drive control means controls the waveform of the column voltage applied in at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. When the configuration is changed with respect to the column voltage waveform in other periods, it is possible to suppress the occurrence of horizontal display unevenness that occurs in the selected row immediately before and immediately after the non-display period.

The deviation of the effective voltage of the horizontal display unevenness depends on the display information. Therefore, the column electrode drive control means performs one horizontal scanning period immediately before the non-display period and the column electrode drive control means immediately after the non-display period. If the configuration is such that the waveform of the column voltage applied in at least one of the one horizontal scanning period is changed according to the display information with respect to the waveform of the column voltage in the other period, the horizontal The occurrence of display unevenness in the direction can be suppressed.

Further, it is assumed that the first column voltage control means applies a column voltage corresponding to a column voltage in one horizontal scanning period immediately before the non-display period in the first one horizontal scanning period in the non-display period. Since the change in the column voltage waveform accompanying the change from the display period to the non-display period can be controlled, it is possible to suppress the occurrence of horizontal display unevenness that occurs in the selected row immediately before the non-display period.

The first column voltage control means applies a column voltage corresponding to the column voltage in one horizontal scanning period immediately before the non-display period in the first half of the first one horizontal scanning period in the non-display period. With this configuration, it is possible to control the change in the column voltage waveform at the transition point from the display period to the non-display period, so that it is possible to suppress the occurrence of horizontal display unevenness that occurs in the selected row immediately before the non-display period. it can. In addition, the time width of the column voltage applied in the non-display period can be minimized, and the decrease in the contrast ratio due to the decrease in the on / off ratio can be minimized.

Further, the first column voltage control means applies the same column voltage as the column voltage in one horizontal scanning period immediately before the non-display period in the first one horizontal scanning period in the non-display period. Then, the position of the change point of the column voltage waveform accompanying the change from the display period to the non-display period can be shifted to the non-display period side by one horizontal scanning period, so that it occurs in the selected row immediately before the non-display period. The occurrence of display unevenness in the horizontal direction can be suppressed.

Furthermore, if the same column voltage as the column voltage in one horizontal scanning period immediately before the non-display period is applied to the first half of the first one horizontal scanning period in the non-display period, the non-display period starts in the non-display period. Since the position of the change point of the column voltage waveform accompanying the change to the period can be shifted, it is possible to suppress the occurrence of horizontal display unevenness that occurs in the selected row immediately before the non-display period. In addition, the time width of the column voltage applied in the non-display period can be minimized, and the decrease in the contrast ratio due to the decrease in the on / off ratio can be minimized.

Further, the second column voltage control means may apply a column voltage corresponding to a column voltage in one horizontal scanning period immediately after the non-display period in the last one horizontal scanning period of the non-display period. Since the change in the column voltage waveform accompanying the change from the non-display period to the display period can be controlled, it is possible to suppress the occurrence of horizontal display unevenness that occurs in the selected row immediately after the non-display period.

Further, the second column voltage control means applies a column voltage corresponding to the column voltage in one horizontal scanning period immediately after the non-display period in the latter half of the last one horizontal scanning period in the non-display period. With this configuration, it is possible to control the change in the column voltage waveform due to the change from the non-display period to the display period, so that it is possible to suppress the occurrence of horizontal display unevenness that occurs in the selected row immediately after the non-display period. it can. In addition, the time width of the column voltage applied in the non-display period can be minimized, and the decrease in the contrast ratio due to the decrease in the on / off ratio can be minimized.

Further, the second column voltage control means applies the same column voltage as the column voltage in one horizontal scanning period immediately after the non-display period in the last one horizontal scanning period of the non-display period. Then, the change in the column voltage waveform at the transition point from the non-display period to the display period can be shifted toward the non-display period by one horizontal scanning period, so that the horizontal display that occurs in the selected row immediately after the non-display period. The occurrence of unevenness can be suppressed.

Further, if the same column voltage as the column voltage in one horizontal scanning period immediately after the non-display period is applied to the latter half of the last one horizontal scanning period of the non-display period, the display is started from the non-display period. Since the position of the changing point of the column voltage waveform due to the change to the period can be controlled, it is possible to suppress the occurrence of the horizontal display unevenness that occurs in the selected row immediately after the non-display period. In addition, the time width of the column voltage CV applied during the non-display period can be minimized, and the decrease in the contrast ratio due to the decrease in the on / off ratio can be minimized.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a matrix display device of the present invention.

FIG. 2 is a time chart showing control signals in the matrix type display device according to the first embodiment of the present invention.

FIG. 3 is a time chart showing control signals in a matrix type display device according to a second embodiment of the present invention.

FIG. 4 is a time chart showing control signals in a matrix type display device according to a third embodiment of the present invention.

FIG. 5 is a time chart showing control signals in a matrix type display device according to a fourth embodiment of the present invention.

FIG. 6 is a diagram for explaining a mechanism for generating display unevenness in a horizontal direction.

FIG. 7 is a diagram for explaining another mechanism for generating display unevenness in the horizontal direction.

FIG. 8 is a diagram for explaining the effect of the selective pulse shaving method.

FIG. 9 is a diagram for explaining another effect of the selective pulse shaving method.

FIG. 10 is a time chart showing control signals in a matrix type display device when a selective pulse shaving method is adopted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal panel 2 Row electrode drive circuit 3 Column electrode drive circuit 4 Memory 5 Arithmetic circuit 6 Function generator 7 Voltage generation circuit 8 Control circuit 11 Row electrode 12 Column electrode 22 Row electrode drive control means 23 Selection voltage control means 24 Correction voltage control Means 25 means for changing row voltage waveform according to display information 26 column electrode drive control means 27 first column voltage control means 28 second column voltage control means 29 means for changing column voltage waveform according to display information

Claims (10)

[Claims] 1. A matrix type in which a plurality of row electrodes and a plurality of column electrodes are arranged to cross each other, and pixels formed at intersections of the row electrodes and the column electrodes are arranged in a matrix. A display device, comprising: a non-display period equal to or longer than one horizontal scanning period in which all the row electrodes are not selected; and a horizontal scanning period immediately before the non-display period and a horizontal scanning period immediately after the non-display period. A matrix type display device having a row electrode drive control means for changing a waveform of a row voltage applied in at least one of the periods to a waveform of a row voltage in another period. 2. The method according to claim 1, wherein the row voltage includes a selection voltage for selecting the row electrode and a non-selection voltage that does not select the row electrode. A matrix display device fixed to a selection voltage, wherein the matrix voltage is applied during at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. 2. The matrix type display device according to claim 1, further comprising a selection voltage control means for changing an application time width of the selection voltage with respect to other periods. 3. The method according to claim 1, wherein the row voltage includes a selection voltage for selecting the row electrode, a non-selection voltage for not selecting the row electrode,
The correction voltage applied during at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. 2. A matrix type display device according to claim 1, further comprising a correction voltage control means for changing the voltage during the period. 4. The row voltage applied in at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. The matrix type display device according to any one of claims 1 to 3, further comprising means for changing the waveform of (i) with respect to the waveform of the row voltage in other periods in accordance with display information. 5. A matrix type in which a plurality of row electrodes and a plurality of column electrodes are arranged so as to intersect with each other, and pixels formed at intersections of the row electrodes and the column electrodes are arranged in a matrix. A display device, comprising: a non-display period equal to or longer than one horizontal scanning period in which all the row electrodes are not selected; and a horizontal scanning period immediately before the non-display period and a horizontal scanning period immediately after the non-display period. A matrix type display device having column electrode drive control means for changing a waveform of a column voltage applied in at least one of the periods to a waveform of a column voltage in another period. 6. The column voltage applied during at least one of one horizontal scanning period immediately before the non-display period and one horizontal scanning period immediately after the non-display period. 6. The matrix type display device according to claim 5, further comprising means for changing the waveform of the column voltage according to the display information with respect to the waveform of the column voltage in other periods. 7. A matrix type in which a plurality of row electrodes and a plurality of column electrodes are arranged to intersect with each other, and pixels formed at intersections of the row electrodes and the column electrodes are arranged in a matrix. A display device, comprising: a non-display period of one or more horizontal scanning periods in which all the row electrodes are not selected; and a non-display period in the first one horizontal scanning period of the non-display period or the first half of the one horizontal scanning period. A matrix type display device having first column voltage control means for applying a column voltage according to a column voltage in one horizontal scanning period immediately before a display period. 8. The matrix type display device according to claim 7, wherein said first column voltage control means is configured to apply the same column voltage as a column voltage in one horizontal scanning period immediately before said non-display period. 9. A matrix type in which a plurality of row electrodes and a plurality of column electrodes are arranged to cross each other, and pixels formed at intersections of the row electrodes and the column electrodes are arranged in a matrix. A display device, comprising: a non-display period of one or more horizontal scanning periods in which all the row electrodes are not selected; and the non-display period in the last one horizontal scanning period of the non-display period or the latter half of the one horizontal scanning period. A matrix type display device including a second column voltage control unit for applying a column voltage according to a column voltage in one horizontal scanning period immediately after a display period. 10. The matrix-type display device according to claim 9, wherein said second column voltage control means is configured to apply the same column voltage as a column voltage in one horizontal scanning period immediately after said non-display period.