JPH11337905A - Simple matrix type liquid crystal display device and driving method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device improved in display unevenness by performing the correction for fixing a scanning selection pulse at a non-selected potential for a fixed period according to a correction level and the correction for re-set the scanning selection pulse at a correction potential different from the selected potential. SOLUTION: A correction quantity data generation part 1 generates a correction quantity data for correcting a waveform of a scanning selection pulse. The generated correction quantity data is supplied to a selected potential period signal generation part 2 and a horizontal correction period signal generation part 3. The selected potential period signal generation part 2 generates a timing signal for changing over a selected potential to a non-selected potential for a fixed period of the scanning selection pulse. The horizontal correction potential signal generation part 3 generates a timing signal for changing over a selected potential of the scanning selection pulse to other correction potential than the selected potential for a part of the period for impressing the selected potential of the scanning selection pulse. Thus the scanning selection pulse is corrected in an effective value by the obtained correction data signal and outputted to a liquid crystal panel 7 from a scanning driver 4 with the same timing as a data driver 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to information equipment, AV
The present invention relates to a simple matrix type liquid crystal display device used for a display device such as an audio visual device and an advertisement display, and a driving method thereof.

[0002]

2. Description of the Related Art In a simple matrix type liquid crystal display device, a liquid crystal layer is sandwiched between two opposing transparent substrates, provided on each liquid crystal layer side of each transparent substrate, and provided at an intersection of a scanning electrode and a data electrode which intersect each other. A voltage is applied from each electrode, and a display is performed by utilizing the electric field-optical characteristic change of the liquid crystal. Each intersection corresponds to a pixel, and the pixels are arranged in a matrix on the entire liquid crystal panel.

[0003] STN (Super Twisted N)
In an effective value response type simple matrix type liquid crystal display device such as a liquid crystal display device, a scan selection pulse from a time-division scanning electrode and a data voltage from a corresponding data electrode are applied. The liquid crystal responds to the effective value (effective voltage value).

Accordingly, variations in the characteristics of the liquid crystal in the liquid crystal panel, wiring resistances (hereinafter referred to as electrode wiring resistances) of the lead wires of the data electrodes and the scanning electrodes, capacitance components of the liquid crystal, and deviations in the voltage application timing are caused. A slight change in the effective voltage value from the ideal value due to this will appear as display unevenness.

Further, in a simple matrix type liquid crystal display device such as an STN or the like, electro-optical characteristics are different between a center portion and an end portion of the liquid crystal panel due to unevenness in cell thickness of the liquid crystal panel generated during the manufacturing process and alignment characteristics of the liquid crystal. And the optimum effective voltage value applied to the liquid crystal is different between the center part and the end part, so that display unevenness occurs.

Further, in a transmissive simple matrix type liquid crystal display device using a backlight system such as a cold cathode tube, the voltage-transmittance curve of the liquid crystal is shifted due to the heat generated by the light emitting portion of the backlight system, and the original voltage is applied. There is a difference in transmittance even though the voltage is the same. as a result,
The characteristics of the liquid crystal change depending on the distance from the heat source, which appears as display unevenness.

More specifically, the transmittance increases as the distance from the heat source increases, and the display appears white. In liquid crystal display devices up to about 13 to 15 inches, the upper and lower ends of the liquid crystal panel are cooled in parallel with the scanning electrodes. In many cases, a cathode ray tube is provided, so that the display goes out white at the upper and lower ends of the liquid crystal panel where the heat source is present, resulting in display unevenness at the center and upper and lower ends of the liquid crystal panel.

In order to solve such a problem of display unevenness, Japanese Patent Application Laid-Open No. 7-20483 discloses a technique for giving a difference in electrode wiring resistance according to the display unevenness.

Normally, when charging and discharging the liquid crystal panel, the waveform actually applied to the liquid crystal is distorted due to the resistance values of the wiring lines of the scanning / data electrodes and the internal resistance of the driving circuit. Due to this effect, the effective voltage value applied to the liquid crystal changes. Therefore, in the above-mentioned publication, the difference in the effective voltage causing the above-mentioned display unevenness is compensated by giving a difference in the electrode wiring resistance and changing the degree of the waveform distortion generated for each electrode, and To supply an appropriate effective voltage value.

Japanese Patent Laid-Open Publication No. Hei 8-201779 discloses electro-optics of a central portion and an end portion of a liquid crystal panel caused by the influence of heat generated from a lamp of an edge light type backlight provided at the upper and lower ends of the liquid crystal panel. In order to improve display unevenness due to the difference in characteristics, the selection potential of the scan selection pulse supplied to each scan electrode is controlled in accordance with the temperature distribution on the liquid crystal panel predicted in advance, and the effective potential of each part of the liquid crystal panel is controlled more appropriately. A technique for supplying voltage is shown.

[0011]

However, the method of compensating for the effective value due to the loss of the applied voltage waveform due to the electrode wiring resistance disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 7-20483 has the following problems.

That is, if the waveform distortion of the selection pulse due to the increase in the electrode wiring resistance increases, the crosstalk increases and the display quality deteriorates. Another problem is that the amount of change in the effective voltage value is affected by the number of inversions of the potential polarity applied to the data electrode. This is because the amount of improvement varies depending on the display pattern. Assuming that it is applied as it is, there is a display pattern dependency. In addition, since the electrode wiring resistance is determined at the stage of manufacturing the liquid crystal panel, it cannot cope with a temporal change such as display unevenness due to heat after the start of display.

On the other hand, in the method disclosed in Japanese Patent Application Laid-Open No. Hei 8-201779, there is no difference in effect depending on the display pattern because waveform distortion is not used in principle. However, on the other hand, it is necessary to change the output of the selection voltage supply circuit in an analog manner as needed. Therefore, it is difficult to stabilize the potential with a simple circuit configuration, and the liquid crystal panel is susceptible to the waveform distortion generated at the time of charge and discharge of the liquid crystal panel, which causes an increase in crosstalk. Also,
Stabilizing the potential complicates the power supply circuit.

The present invention has been made in view of such a problem, and does not use the effect of changing the effective voltage value due to charge / discharge of electric charge to / from the liquid crystal panel, and applies the voltage to each electrode of the liquid crystal panel. An object of the present invention is to provide a liquid crystal display device in which display unevenness is improved by applying an appropriate effective voltage value to each part of a liquid crystal panel without changing a potential in an analog manner as needed.

[0015]

According to a first aspect of the present invention, there is provided a driving method of a simple matrix type liquid crystal display device, wherein a plurality of scanning electrodes and a plurality of data electrodes are formed in a liquid crystal layer. Are arranged to intersect each other through
In a driving method of a simple matrix type liquid crystal display device having a liquid crystal panel in which pixels are arranged in a matrix corresponding to an intersection of both electrodes, a waveform of a scanning selection pulse applied to a scanning electrode to compensate for display unevenness. In contrast, a first correction for fixing a fixed period during the selection potential application period to a non-selection potential according to a correction level for each scan electrode to be corrected, and a part of a period during which the selection potential is actually applied And a second correction for resetting the correction potential to a correction potential different from the selection potential.

According to this, the effective voltage value applied to each part of the liquid crystal panel is fixed to a non-selection period during a selection potential application period according to the correction level for each scan electrode to be corrected. 1 and a second correction in which a part of the period in which the selection potential is actually applied is further set to a correction potential different from the selection potential.

Thus, the effect of changing the effective voltage value due to the charging and discharging of the electric charge to and from the liquid crystal panel is not used, and the potential applied to each electrode of the liquid crystal panel is not changed analogously as needed. An appropriate effective voltage value can be supplied to the portion, and display unevenness caused by this can be improved. A configuration example of a simple matrix type liquid crystal display device which can realize the present invention is described in claim 5.

According to a fifth aspect of the present invention, there is provided a simple matrix type liquid crystal display device, wherein a plurality of scanning electrodes and a plurality of data electrodes are arranged so as to intersect with each other via a liquid crystal layer. In a simple matrix type liquid crystal display device having a liquid crystal panel in which pixels are arranged in a matrix corresponding to the intersection of both electrodes, the waveform of a scan selection pulse applied to the scan electrode is compensated for display unevenness. A correction amount data generating unit for generating correction amount data for correcting a part of the scan selection pulse for each scanning electrode to be corrected based on the correction amount data from the correction amount data generating unit. A selection potential period signal generation unit for generating a selection potential period signal for fixing to a selection potential, and a scan electrode to be corrected based on correction amount data from the correction amount data generation unit. A correction period signal generator for generating a correction period signal for making a part of the period in which the selection potential is actually applied a correction potential different from the selection potential, and a selection period output from the selection potential period signal generator. A scan driver that applies a scan selection pulse output-controlled by the potential period signal and the correction period signal output from the correction period signal generator to the scan electrode based on a synchronization signal in the scanning direction. And

According to this, the correction amount data generation section generates correction amount data for each scanning electrode according to, for example, a heat source or a distance from the upper and lower ends of the liquid crystal panel, and generates a selection potential period signal generation section and a correction period signal. If requested by the generator, correction amount data for each scanning electrode is given to them.

The selection potential period signal generation unit is adapted to select a selection potential for fixing a part of the selection voltage of the scanning selection pulse applied to each synchronization signal to a non-selection potential according to the correction amount data from the correction amount data generation unit. Generate a period signal. The period during which the potential is fixed at the non-selection potential is set longer for a scanning electrode whose transmittance is to be reduced.

The correction period signal generator determines an application period of the correction potential for each target scan electrode according to the correction amount data from the correction amount data generator, and applies the correction potential during the determined application period. Is generated.

The scan driver applies a scan selection pulse to the liquid crystal panel according to a synchronization signal supplied from a liquid crystal controller or the like. At this time, the scan driver switches a partial period of the output scanning selection pulse from the selection potential to the non-selection potential in accordance with the selection potential period signal from the selection potential period signal generation unit. Further, the scan driver receives a correction period signal from the correction period signal generation unit, and applies a period correction potential required for each scanning electrode during the selection period to the liquid crystal panel.

According to a second aspect of the present invention, there is provided a driving method of a simple matrix type liquid crystal display device in the configuration of the first aspect, wherein a correction potential used for other measures against crosstalk such as dielectric constant compensation for a scanning electrode. , The existing correction potential is used as a correction potential used for the second correction.

According to this, when there is a correction potential used for other measures against crosstalk such as permittivity compensation for the scanning electrode, the application period of this correction potential is increased or decreased,
A second correction is performed. Therefore, the power supply circuit for the correction potential used for the second correction is not separately provided, and the second correction can be performed using the existing power supply circuit. A configuration example of a simple matrix type liquid crystal display device which can realize the present invention is described in claim 6.

According to a sixth aspect of the present invention, in the simple matrix type liquid crystal display device according to the fifth aspect, a part of a period during which the selection potential of the scanning selection pulse is applied is used for compensating a dielectric constant of the scanning electrode. A horizontal correction period signal generation unit for generating a horizontal correction period signal for setting a correction potential, and having the horizontal correction period signal generation unit also function as the correction period signal generation unit; The correction potential is used as the correction potential.

According to this, the horizontal correction period signal generation unit:
In accordance with the correction amount data from the correction amount data generation unit, the amount of increase or decrease in the application period of the correction potential for dielectric constant compensation (hereinafter, horizontal correction potential) is determined for each target scan electrode, and the original horizontal correction application period is determined. To generate a horizontal correction application period signal that is extended or shortened.

According to a third aspect of the present invention, there is provided a driving method of a simple matrix type liquid crystal display device, wherein a driving method in which a plurality of scanning electrodes are simultaneously selected and driven is applied. The first correction is performed with the same correction amount for the scan electrode group to which the scan selection pulse is applied at the same time, and the second correction is performed independently for each scan electrode in the scan electrode group. I have.

According to a seventh aspect of the present invention, there is provided a simple matrix type liquid crystal display device according to the fifth or sixth aspect, wherein the selection potential period signal generation unit is configured to simultaneously apply a scanning selection pulse to a scanning electrode. The same selection potential period signal is generated for each group, and the correction period signal generation unit generates a correction period signal independently for each scan electrode in the scan electrode group.

The effective value of the scan selection pulse applied to the scan electrode to be corrected is partially fixed to the non-selection potential by the first correction or the correction based on the selection potential period signal. As a result, the transmittance also decreases, and the display unevenness is corrected. However, for example, in the case of the MLS drive in which the number of simultaneously selected lines is four in a dual scan liquid crystal display device (details will be described later), the selection potential is SVGA resolution (800 pixels ×
600 line) and about 20V, also XGA resolution (1
024 pixels x 768 line) 25-30V
And the amplitude of the scan selection pulse voltage relative to the time axis of the effective voltage becomes relatively large, so that a slight difference in the period set to the non-selection potential in the adjacent scan electrode eventually makes the luminance visually recognizable. Will appear as a difference. Also,
In normal line-sequential driving, the pulse height of the scan selection pulse is even larger than in MLS driving.

Therefore, the application period of the correction potential of each scanning electrode is increased or decreased according to the difference in luminance between adjacent scanning electrodes. This complements the difference in brightness between the scanning electrodes,
Smooth correction can be realized. In Claims 4 and 8,
An example of a method of obtaining the correction amount of the second correction or the correction amount of the correction period signal generation unit will be described.

According to a fourth aspect of the present invention, there is provided a driving method of a simple matrix type liquid crystal display device according to the third aspect, wherein the correction amount of the second correction is set to a scanning electrode group to be corrected. A first correction amount for the scan electrode group selected before the scan electrode group selected before the first scan electrode group is selected, or a first correction amount for the scan electrode group selected after the scan electrode group to be corrected is selected.
Alternatively, it is characterized in that it is calculated by a complementary operation from both of them.

Further, the simple matrix type liquid crystal display device according to claim 8 of the present invention has a structure according to claim 7,
The correction period signal generator includes a correction amount for a scan electrode group used before the scan electrode group to be corrected is selected, which is used by the selection potential period signal generator to generate the selection potential period signal, or It is characterized in that a correction amount for generating a correction period signal is obtained by performing a complementary calculation from a correction amount for a scan electrode group selected after the scan electrode group to be corrected is selected, or both.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described below with reference to FIGS.

FIG. 1 shows a configuration of a simple matrix type liquid crystal display device (hereinafter simply referred to as a liquid crystal display device) of the present embodiment.

As shown in FIG. 1, the liquid crystal display device comprises a correction amount data generator 1, a selection potential period signal generator 2, a horizontal correction period signal generator 3, a scanning driver 4, a data driver 6, a liquid crystal controller 5, And a liquid crystal panel 7.

Although not specifically shown, the liquid crystal panel 7 has a pair of transparent substrates opposed to each other with a liquid crystal layer interposed therebetween. On the liquid crystal layer surface of these transparent substrates, a scanning electrode having a stripe shape and a data electrode having a stripe shape are formed so as to cross each other. The pixels correspond to the intersections of the scanning electrodes and the data electrodes, and are arranged in a matrix on the entire liquid crystal panel 7.

In the present embodiment, an MLS (Multiple Line Select) for simultaneously applying a scanning selection pulse to L (≧ 2) scanning electrodes in the liquid crystal panel 7.
Tion method (TN Ruckmongathan)
et al. Japan Display 92. Di
gest, p. 65, JP-A-5-46127, etc.)
A description will be given of the case of driving by the following. FIG. 2 shows how a scanning selection pulse is applied by MLS driving.

The liquid crystal controller 5 outputs a horizontal synchronizing signal, a vertical synchronizing signal, a clock signal, and a data signal. The horizontal synchronizing signal is generated by the selection potential period signal generator 2,
The signal is input to the horizontal correction period signal generator 3 and the scanning driver 4. The data driver 6 is supplied with a data signal and a horizontal synchronization signal. If necessary, a clock signal and a vertical synchronizing signal are used in each section.

The correction amount data generating section 1 generates correction amount data for correcting the waveform of the scan selection pulse so as to eliminate display unevenness caused by the difference in the optimum voltage value in each part of the liquid crystal panel, Upon receiving a request from the signal generation unit 2 or the horizontal correction period signal generation unit 3, the generated correction amount data is provided to the selected potential period signal generation unit 2 and the horizontal correction period signal generation unit 3.

The correction data generator 1 is, for example, a ROM
(Read Only Memory) and LUTs (Look Up Table) such as combinational logic circuits
Can be configured.

As described above, due to the uneven cell thickness of the liquid crystal panel 7 and the alignment characteristics of the liquid crystal, a difference occurs in the electro-optical characteristics between the center and the end of the liquid crystal panel 7, and the liquid crystal is formed between the center and the end. The applied optimum effective voltage value is different. Here, the correction amount is set for each of the L scanning electrodes driven in the same manner according to the distance from the upper and lower ends of the liquid crystal panel 7 (parallel to the scanning electrodes).

Further, in the liquid crystal display device of the present embodiment,
A heat sensor (not shown) using a thermistor or the like is provided, and the output (correction amount data) of the LUT or the like is modified according to information from the heat sensor. This makes it possible to directly respond to a temporal change such as the influence of heat after the start of display. However, although it is not possible to directly cope with this, instead of using a configuration including a heat sensor as in the present embodiment,
A configuration in which the above-described correction amount is set as a setting element for a distance from a backlight (disposed in parallel with the scanning electrode) as a heat source may also be used.

The selection potential period signal generator 2 switches a partial period of the scan selection pulse from the selection potential to the non-selection potential according to the correction amount data sent from the correction amount data generator 1 (first correction). ) Is generated.

FIG. 3 shows an example of the configuration of the selection potential period signal generator 2. Correction data sent from the correction amount data generating unit 1, the period for setting the scanning selection pulse to the non-selection potential, that is, it is assumed to provide a cutting width of scanning selection pulse, scan selection applied at time T _k The correction amount for the pulse is d (T _k ).

The selection pulse width counter 21 uses the horizontal synchronization signal input from the liquid crystal controller 5 (see FIG. 1), counts the width of the horizontal synchronization period (= original scanning selection pulse application period) with a clock, The value is stored in register 22
Set to. In the case where the portion before and after the scan selection pulse is set to a non-selection potential (scan display off) in advance by using the scan driver display off signal for reasons such as measures against crosstalk, the selection pulse width counter 21 The application period of the correct scan selection pulse is counted using the scan driver display off signal together with the horizontal synchronization signal.

The correction counter 23 loads the correction amount data at the rising edge of the scan driver display OFF signal (starts the scanning display) and starts counting up. The output of the correction counter 23 is input to one input terminal of the comparator 24. The output of the register 22 is input to the other input terminal of the comparator 24.

The comparator 24 compares the output of the correction counter 23 with the output of the register 22, and outputs high when both input data do not match, and outputs low when they match. The output of the comparator 24 is output from the selection potential period signal generator 2 as a selection potential period signal, and is connected to the enable terminal of the correction counter 23. As a result, as shown in FIG. 4, the selection potential period signal rises at the same time as the scan driver display off signal, and can fall earlier by the correction amount data.

The scanning driver 4 outputs the selection potential period signal h.
During the high period, a selection potential is output from the scanning electrode which is in a selected state as before, and a non-selection potential is output when the selection potential period signal becomes low. Therefore, here, the outputs of the L scanning electrodes simultaneously change from the positive or negative selection potential to the intermediate non-selection potential.

The horizontal correction period signal generation unit 3 is normally
In order to eliminate display unevenness due to a change in the dielectric constant of the liquid crystal due to the ratio of the number of off pixels, a part of the period in which the selection potential of the scanning selection pulse is applied is set to a correction potential different from the selection potential (hereinafter referred to as a horizontal correction potential) ) Is generated.

The lateral correction for a change in the dielectric constant will be briefly described. Now, focusing on a certain scanning electrode, the dielectric constant of the liquid crystal changes depending on the ratio of ON / OFF pixels on the scanning electrode. That is, the dielectric constant of the liquid crystal on the scan electrode having many ON pixels (white display = lighting in a normally black liquid crystal display device) is larger than that of the liquid crystal on the scan electrode having many OFF pixels (also black display = non-lighting). Therefore, the transmittance decreases and the display of the pixel located on the scanning electrode becomes dark.

In response to this phenomenon, a correction potential (hereinafter referred to as a horizontal correction potential) different from the selection potential is applied to some of the scanning selection periods according to the ratio of the ON pixel to the OFF pixel on the scanning electrode. Correction for eliminating display unevenness for each scanning electrode is horizontal correction (see Japanese Patent Application Laid-Open No. 2-89, etc.).

The horizontal correction potential is set so as to have a difference of about 5% with respect to the original selection potential of the scanning selection pulse with respect to the non-selection potential (see FIG. 8). This is because if the horizontal correction potential is too large, there is a concern that the scanning voltage will exceed the withstand voltage of the scan driver that actually applies the scanning voltage to the liquid crystal panel, and the difference in dielectric constant is obtained by balancing the time axis and voltage value for correction. This is to ensure that a linear correction amount to is accurately applied.

In the liquid crystal display device of the present embodiment, the horizontal correction period signal generator 3 also functions as a correction period signal generator in the present invention, and the time for setting the selection potential to the horizontal correction potential. Is extended based on the correction amount data generated by the correction amount data generation unit 1 described above.

FIG. 5 shows an example of the configuration of the horizontal correction period signal generator 3. The correction amount data capturing units 31a and 31b select each of the L scan electrodes to be corrected and the L scan electrodes selected after one adjacent horizontal synchronization period, which are captured from the correction amount data generation unit 1. The pulse shaving amount (correction amount data: d (T _k ) and d (T _{k + 1} )) is passed to the subtractor 32, where the difference between them is calculated and input to the complement amount data generation unit 33.

The complementary amount data generating unit 33 calculates the time difference Δ (T _k ), Δ (T _k ) = d (T _k ) −d of the scan selection pulse shaving amount between adjacent scan electrode groups obtained by the subtractor 32. Based on (T _{k + 1} ), for each of the L scan electrodes to be corrected,
For example, each correction amount (extended period of the horizontal correction potential) is calculated by linear interpolation represented by the following equation.

Τ _i (T _k ) = (i−1 / L−1) Δ (T _k ) a where, i: l ≦ i ≦ L τ _i : a lateral correction extension period for the i-th scan selection pulse in L Δ: Difference in the amount of scan selection pulse shaving between adjacent parts L: Number of simultaneous selections (L ≧ 2) a: Correction coefficient where a is the difference Δ in the effective value loss of the scan electrode group
It is set to an amount that can be complemented by the number of scanning electrodes.

In this example, the complementary data is calculated by linear interpolation from the correction information of the L scanning electrodes to be corrected and the adjacent L scanning electrodes. There is no problem in calculating.

The lateral correction complement calculated by the complement data generator 33 is generated by the lateral correction data generator 34 which generates lateral correction data for the change in the dielectric constant of the liquid crystal depending on the on / off pixel number ratio. The original lateral correction amount for each of the scanning electrodes is added in the adder 35, and the result is given to the scanning driver 4 as L lateral correction data.

With the correction data signals obtained from the selection potential period signal generator 2 and the lateral correction period signal generator 3 obtained as described above, the scan selection pulse is corrected in effective value as shown in FIG. 4 is output to the liquid crystal panel 7 at the same timing as the data driver 6.

FIG. 7 shows an actual output waveform of the scanning driver 4 at this time. In FIG. 7, for convenience of explanation, the conventional lateral correction amount for each scanning electrode is assumed to be equal.

Further, when the configuration of the liquid crystal display device of the present embodiment was applied to an STN liquid crystal display device of a dual scan XGA resolution driven by four simultaneous selections, a good correction effect could be confirmed.

Note that only the horizontal correction period signal generator 3 is used,
The problem of the present invention can be solved and the effective value can be compensated only by changing the period during which the horizontal correction potential is applied to the scanning selection pulse.

That is, in order to correct an increase in transmittance due to heat of a lamp or the like from the upper and lower ends of the panel by using the horizontal correction potential, the horizontal correction amount applied to the scanning electrodes close to the heat source may be reduced (or the entire panel). After the effective voltage applied to the scanning electrode is lowered, the lateral correction amount increases as the scanning electrode is farther from the heat source).

However, since the horizontal correction potential is only about 5% of the selected potential with respect to the non-selection potential, the correction effect is not so great. Since the amount of increase / decrease of the correction amount that can be assigned to the countermeasure for the display unevenness due to the heat from the amount is not large, the display unevenness cannot be corrected as much as the present invention in which the correction is performed in two steps.

In addition, the problem of the present invention can be solved by only using the selection potential period signal generator 2 and correcting only a part of the selection potential application period of the scanning selection pulse to be unselected.
It is possible to compensate for the effective value.

However, a large screen of the liquid crystal display device is required.
Because the selection potential has increased with the increase in detail,
The voltage amplitude value of the effective voltage with respect to the time axis on the scanning side is relatively large. For this reason, it is necessary to control the time for fixing to the non-selection potential with high accuracy according to the distance from the heat source and the distance from the panel end.

Further, when the present invention is applied to the MLS driving method used in the liquid crystal display device of the present embodiment, a scanning selection pulse is applied to a plurality of scanning electrodes at the same time in the MLS driving method. It is necessary to fix a part of the scan selection period to the non-selection potential independently for each electrode, which complicates the circuit configuration of the scan driver.

That is, the liquid crystal display device employing the above-described two-stage correction of the present invention accurately corrects the effective value for each pixel and has a liquid crystal display device having correction means applicable to the MLS driving method. Equipment can be provided.

[0069]

According to the driving method of the simple matrix type liquid crystal display device according to the first aspect of the present invention, as described above, the waveform of the scan selection pulse applied to the scan electrode is corrected to compensate for the display unevenness. In accordance with the correction level for each target scan electrode, a first correction in which a fixed period during the selection potential application period is fixed to a non-selection potential, and a part of the period in which the selection potential is actually applied is further changed to the selection potential. Is a configuration for performing the second correction for resetting to a different correction potential.

In the simple matrix type liquid crystal display device according to the fifth aspect of the present invention, as described above, the correction amount data for correcting the waveform of the scan selection pulse applied to the scan electrode so as to compensate for display unevenness is provided. A correction amount data generator to be generated, and a selection potential for fixing a part of the scan selection pulse to a non-selection potential for each scan electrode to be corrected based on the correction amount data from the correction amount data generator. A selection potential period signal generation unit for generating a period signal, and a part of a period in which a selection potential is actually applied for each scan electrode to be corrected based on the correction amount data from the correction amount data generation unit. A correction period signal generation unit for generating a correction period signal for making a correction potential different from the selection potential; a selection potential period signal output from the selection potential period signal generation unit;
And a scan driver for applying a scan selection pulse output-controlled by the correction period signal output from the correction period signal generator to the scan electrode based on a synchronization signal in the scanning direction.

Thus, the effect of changing the effective voltage value due to the charging and discharging of the electric charge to and from the liquid crystal panel is not used, and the potentials applied to the respective electrodes of the liquid crystal panel are not changed analogously as needed. It is possible to supply an appropriate effective voltage value to the portion, and it is possible to correct display unevenness due to this more smoothly and accurately, thereby providing a liquid crystal display device with high display quality. It works.

According to a second aspect of the present invention, there is provided a driving method for a simple matrix type liquid crystal display device, wherein the correction potential used for other measures against crosstalk, such as dielectric constant compensation for a scanning electrode, is provided. , The existing correction potential is used as the correction potential used for the second correction.

According to a sixth aspect of the present invention, in the simple matrix type liquid crystal display device according to the fifth aspect, a part of a period during which the selection potential of the scanning selection pulse is applied is used for compensating a dielectric constant with respect to the scanning electrode. A horizontal correction period signal generation unit for generating a horizontal correction period signal for setting a correction potential, and having the horizontal correction period signal generation unit also function as the correction period signal generation unit; The correction potential is used as the correction potential.

Thus, if there is a correction potential used for other crosstalk measures such as dielectric constant compensation for the scanning electrode, this correction potential is used to provide a correction potential for the second correction. Since it is not necessary to provide a power supply circuit separately, as a result, there is an effect that a liquid crystal display device with high display quality can be provided in a smaller size and at lower cost.

According to a third aspect of the present invention, there is provided a driving method of a simple matrix type liquid crystal display device, wherein a driving method in which a plurality of scanning electrodes are selected and driven at the same time is applied. The first correction is performed with the same correction amount for the scan electrode group to which the scan selection pulse is applied at the same time, and the second correction is performed independently for each scan electrode in the scan electrode group.

In a simple matrix type liquid crystal display device according to a seventh aspect of the present invention, in the configuration according to the fifth or sixth aspect, the selection potential period signal generation unit is configured to simultaneously apply a scanning selection pulse to a scanning electrode. The same selection potential period signal is generated for the group, and the correction period signal generation unit is configured to generate the correction period signal independently for each scan electrode in the scan electrode group.

According to a fourth aspect of the present invention, there is provided a driving method of a simple matrix type liquid crystal display device according to the third aspect, wherein the correction amount of the second correction is set to a scanning electrode group to be corrected. A first correction amount for the scan electrode group selected before the scan electrode group selected before the first scan electrode group is selected, or a first correction amount for the scan electrode group selected after the scan electrode group to be corrected is selected.
Alternatively, the configuration is such that the calculation is performed by a complementary operation from both of them.

According to an eighth aspect of the present invention, in the configuration of the simple matrix type liquid crystal display device according to the seventh aspect, the correction period signal generation unit is configured so that the selection potential period signal generation unit uses the selection potential period signal generation unit to generate the selection potential period signal. The correction amount for the scan electrode group selected before the scan electrode group to be corrected is selected, or the correction amount for the scan electrode group selected after the scan electrode group to be corrected is selected, Alternatively, a correction amount for generating a correction period signal is obtained by performing a complementary operation from both of them.

As a result, it is possible to compensate for the difference in luminance between the scanning electrodes and realize smooth correction. Therefore, in the case of the MLS driving method, by adopting the above configuration, a liquid crystal display device having high display quality can be realized. It has the effect that it can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a simple matrix liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a state of a scanning selection pulse for a liquid crystal panel in the liquid crystal display device.

FIG. 3 is a block diagram illustrating a configuration example of a selection potential period signal generation unit in FIG. 1;

FIG. 4 is a waveform diagram illustrating a selection potential period signal generated by a selection potential period signal generation unit in FIG. 3;

FIG. 5 is a block diagram illustrating a configuration example of a horizontal correction period signal generation unit in FIG. 1;

FIG. 6 is an explanatory diagram showing a correction amount of a scanning selection pulse.

FIG. 7 is a waveform diagram showing an output waveform of a corrected scanning selection pulse.

FIG. 8 is an explanatory diagram showing a relationship between a change in a dielectric constant according to display contents of a liquid crystal panel and a correction pulse potential to a scanning electrode.

[Explanation of symbols]

 Reference Signs List 1 correction amount data generation unit 2 selection potential period signal generation unit 3 horizontal correction period signal generation unit 4 scan driver 5 liquid crystal controller 6 data driver 7 liquid crystal panel 21 selection pulse width counter 22 register 23 correction counter 24 comparator 31a capture of correction amount data Unit 31b Correction amount data acquisition unit 32 Subtractor 33 Complement amount data generation unit 34 Horizontal correction data generation unit 35 Adder

Claims (8)

[Claims] 1. A liquid crystal panel in which a plurality of scanning electrodes and a plurality of data electrodes are arranged so as to intersect with each other via a liquid crystal layer, and pixels are arranged in a matrix corresponding to the intersection of the two electrodes. In the driving method for a simple matrix type liquid crystal display device, the waveform of a scan selection pulse applied to a scan electrode is compensated for each scan electrode to be corrected in accordance with a correction level. Performing a first correction for fixing a fixed period of time to a non-selection potential and a second correction for resetting a part of a period during which the selection potential is actually applied to a correction potential different from the selection potential. A driving method of a simple matrix type liquid crystal display device characterized by the above-mentioned. 2. When a correction potential is used for other crosstalk measures such as permittivity compensation for a scan electrode, the existing correction potential is used as a correction potential used for a second correction. The method for driving a simple matrix type liquid crystal display device according to claim 1. 3. When a driving method in which a plurality of scanning electrodes are selectively driven at the same time is applied, a first correction is performed with the same correction amount to a scanning electrode group to which a scanning selection pulse is applied at the same time. 3. The driving method of a simple matrix type liquid crystal display device according to claim 1, wherein the correction of (i) is performed independently for each scanning electrode in the scanning electrode group. 4. A second correction amount is selected by a first correction amount for a scanning electrode group selected before a scanning electrode group to be corrected is selected or by a scanning electrode group to be corrected. 4. The driving method for a simple matrix type liquid crystal display device according to claim 3, wherein the calculation is performed by a complementary operation from the first correction amount for the scan electrode group selected after the operation or both. 5. A liquid crystal panel in which a plurality of scanning electrodes and a plurality of data electrodes are arranged so as to intersect with each other via a liquid crystal layer, and pixels are arranged in a matrix corresponding to the intersection of the two electrodes. A correction matrix data generating section for generating a correction matrix data for correcting a waveform of a scan selection pulse applied to a scan electrode so as to compensate for display unevenness. A selection potential period signal generation unit that generates a selection potential period signal for fixing a part of the scanning selection pulse to a non-selection potential for each scanning electrode to be corrected based on the correction amount data from the unit; Based on the correction amount data from the correction amount data generator, a part of the period in which the selection potential is actually applied is further changed to a correction potential different from the selection potential for each scan electrode to be corrected. Correction period signal generation unit for generating a correction period signal for scanning, and scan selection output controlled by the selection potential period signal output from the selection potential period signal generation unit and the correction period signal output from the correction period signal generation unit A scan driver for applying a pulse to a scan electrode based on a synchronization signal in a scan direction. 6. A horizontal correction period signal generator for generating a horizontal correction period signal for setting a part of a period during which a selection potential of a scan selection pulse is applied to a correction potential for permittivity compensation of a scan electrode. 6. The simple matrix according to claim 5, wherein said horizontal correction period signal generation section also has a function as said correction period signal generation section, and a correction potential for permittivity compensation is used as said correction potential. Liquid crystal display device. 7. The selection potential period signal generator generates the same selection potential period signal for a group of scan electrodes to which a scan selection pulse is applied simultaneously, and the correction period signal generator generates the same selection potential period signal within the scan electrode group. 7. The simple matrix type liquid crystal display device according to claim 5, wherein a correction period signal is generated independently for each of the scanning electrodes. 8. The scan electrode group selected before the scan electrode group to be corrected, which is used by the select potential period signal generator for generating the select potential period signal, is selected from the group consisting of: , Or a correction amount for a scan electrode group selected after the scan electrode group to be corrected is selected, or a complementary operation from both of them to obtain a correction amount for generating a correction period signal. The simple matrix type liquid crystal display device according to claim 7, wherein: