JP2003255306A - Method for driving liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform highly reliable and stable driving suppressed in generation of image persistence and flickers in a method for driving a liquid crystal improved in a visual angle characteristic of TN liquid crystal by performing time-spatial modulation of γ-characteristic by signal processing and controlling the voltage to be applied to the liquid crystal. <P>SOLUTION: The liquid crystal display comprises an RGB independent γ-conversion circuit 1 having a plurality of independent converter circuits for RGB each for obtaining a desired V-T characteristic, a change-over circuit 2, a visual angle adaptive control circuit 3 for optimally controlling a plurality of γ-data setting and a change- over pattern and performing γ-modulation control so as to improve the visual angle characteristic, and alternation control part 4 for controlling the alternated polarities of the voltage to be applied to liquid crystal pixels, and a liquid crystal panel 5. From the relationship between a γ-modulated pattern and characteristic and an alternated driving state, the γ-modulation characteristic or the alternation is controlled by managing so that the DC component does not remain to liquid crystal pixels. A modulation factor is controlled according to response speed data so as to compensate for variation of γ-modulation characteristic caused by an insufficient liquid crystal response speed to the γ-modulation in the frame direction. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving circuit for a liquid crystal display device of TN liquid crystal (twisted nematic liquid crystal) and signal processing of a video signal input to the liquid crystal display device, and more particularly to signal processing and driving method. Accordingly, the present invention relates to a signal processing and driving method of a liquid crystal display device capable of enlarging and controlling the viewing angle characteristic of the liquid crystal display device.

[0002]

2. Description of the Related Art The TN liquid crystal system, which is widely used in liquid crystal TVs and the like, has various birefringences depending on the direction and angle of light passing through a liquid crystal layer due to the refractive index anisotropy and twist orientation of liquid crystal. Due to the effect, it shows a complicated viewing angle dependency, for example, generally the entire screen becomes whitish at the upward viewing angle, the entire screen becomes dark at the downward viewing angle, and the light and darkness is reversed in the low luminance part of the image. The phenomenon occurs.

With respect to such viewing angle characteristics, various techniques have been developed for widening the viewing angle in terms of brightness, hue, contrast characteristics, gradation characteristics, etc. by various methods.

[0004] As such techniques, there are a lot of general improvements to the liquid crystal panel itself and those using optical members, but the TFT process and the liquid crystal panel process are not complicated, and the yield and the cost are reduced. As a method that does not cause an increase, a technique for widening the viewing angle only by signal processing of an external circuit is also shown. This utilizes the viewing angle dependence of the transmittance characteristic (hereinafter, referred to as VT characteristic) with respect to the applied voltage of the liquid crystal cell, and prepares a plurality of gradation voltage conversion characteristics (hereinafter, referred to as γ characteristic) for an input signal. Then, by driving the liquid crystal while performing this switching control at a predetermined interval, a plurality of characteristics are visually combined to improve the viewing angle characteristics.
144, "Liquid Crystal Display Device", Japanese Patent Laid-Open No. 9-90910
Publication "Liquid Crystal Display Driving Method and Liquid Crystal Display"
Etc. An example of such a conventional wide viewing angle liquid crystal display device by external signal processing is shown in FIG.

In FIG. 10, γ conversion circuits γ1 and γ having a plurality of γ characteristics which are different from each other with an RGB image signal as an input.
2 and means for controlling switching of the γ characteristic for every n frames of the image signal (n is a natural number, n ≧ 2), and liquid crystal driving is performed according to the output of the γ conversion means.
As a switching pattern of the γ characteristic, as shown in FIG.
The GB trio is set as one unit, and the display signals corresponding to the same γ characteristic and having different polarities are applied to corresponding pixels of consecutive n frames. Here, as shown in FIG. 12, the two γ characteristics are optimized so that different viewing angles are optimal viewing angles, for example, γ1 is optimized for the upper visual field of 10 °, γ2 is optimized for the lower visual field of 10 °, and the γ characteristic is fixed. By modulating with the switching pattern, the operation is performed so as to widen the optimum gradation characteristics by about 10 ° above and below.

As described above, in the prior art, as a technique for expanding the viewing angle characteristic (improving the viewing angle characteristic) only by the signal processing of the external circuit, a method of modulating a plurality of fixedly set γ conversion characteristics is used. Is disclosed as a method.

[0007]

However, in the conventional example, the modulation period of γ in the frame direction is limited to two frames or more. The reason why γ is modulated in the frame direction is that the degree of γ modulation is set large in order to obtain a certain viewing angle improving effect (for example, when γ1 and γ2 shown in FIG. If there is a large difference in the γ characteristic of), the modulation pattern of the γ characteristic has the adverse effect that the modulation pattern is recognized as a dot pattern. Together with the effect, it is possible to make the dot pattern difficult to recognize by visual averaging. However, in actuality, if the degree of modulation is set to a certain degree and the processing is performed in this way, flicker is likely to occur, so that the earlier the modulation cycle in the frame direction is advantageous. Further, in a liquid crystal display device, when a direct current component is applied to a liquid crystal pixel, the liquid crystal pixel is deteriorated by an electrochemical reaction, and therefore is always driven by an alternating current. For alternating current in a frame direction, alternating current may be applied for each frame. It is common. However, assuming that the γ modulation period in the frame direction is set for each frame, as shown in FIG. 5, γ1 +, γ2−, γ1 +, γ2−, γ in order in the frame direction for a certain pixel of interest.
1+, γ2-. ． ． ． ． ． , For its neighboring pixels, γ
2+, γ1-, γ2 +, γ1-, γ2 +, γ1
−. ． ． ． ． ． Since γ1 and γ2 are set to different γ values, if γ1> γ2, a positive DC voltage is applied to the former pixel and a negative DC voltage is applied to the latter pixel on average. It will be. Regarding the conventional example, it is considered that the restriction of n ≧ 2 is set in view of this, but in the case of n = 3, the DC component remains similarly as shown in FIG. In the conventional example, there is no disclosure regarding such measures relating to the reliability of the liquid crystal panel.

If the DC component remains in the liquid crystal pixels in this manner, image burn-in (image memory phenomenon) becomes a major cause, and the liquid crystal itself deteriorates due to the electrochemical reaction described above. There are various serious problems such as reduced reliability and flicker.

A second object of the present invention is to provide a plurality of γ characteristics γ to be modulated when performing γ modulation in the frame direction as described above.
Although 1 and γ2 depend on the item of the viewing angle characteristic to be improved, etc., they are usually set so that the difference becomes large especially in the halftone level as shown in FIG. However, in the case of the TN liquid crystal to which the present technology is applied, the response speed of the liquid crystal at the halftone level is generally slower than that at the white or black level, and therefore, the modulation speed cannot keep up with the frame period. There are cases.

That is, in a gradation in which the degree of modulation (difference between γ1 and γ2) is larger than a certain level, a predetermined amplitude (γ
In some cases, 1-γ2) cannot be swung completely, and thus the original effect of improving the viewing angle itself may not be sufficiently obtained. As a result, the equivalent γ characteristic at the time of modulation (equivalent γ characteristic equivalent to the combination of γ1 and γ2) is biased as shown by b in FIG. The desired characteristics may not be obtained.

For this reason, by modulating in the frame direction, the desired modulation cannot be performed and the degree of improvement in the viewing angle characteristics is reduced as compared with the case where no modulation is performed, or the visual characteristics from the front viewing angle direction are significantly reduced. There are problems such as changing.

The present invention is a technique for improving the viewing angle characteristics by such signal processing and drive control so that no direct current component remains in the liquid crystal pixels, so that there is little adverse effect on the image and it is stable and reliable. The purpose is to perform high driving.

Another object of the present invention is to compensate the effect on the viewing angle improving effect itself due to the reversal in the frame direction, and to effectively improve the viewing angle with good image quality.

[0014]

In order to solve such a problem, the present invention provides a method of driving a liquid crystal display device,
R having independent RGB and each having a plurality of γ conversion characteristics
GB independent γ conversion circuit, γ switching circuit for switching output of the RGB independent γ conversion circuit, first viewing angle adaptive control circuit for controlling γ data setting of the RGB independent γ conversion circuit and switching pattern of the γ switching circuit And an alternating current control means for controlling the alternating current polarity of the signal voltage applied to the liquid crystal pixel, and a liquid crystal panel, which is applied to the liquid crystal pixel from the relationship between the γ data setting, the switching pattern and the alternating current polarity. Managing the signal voltage and the polarity, and setting the γ data setting and the switching pattern or the alternating polarity.
The control is performed so that the DC component is not applied to the liquid crystal pixel.

[0015]

Here, the optimum γ modulation pattern is set depending on the viewing angle characteristics to be improved, the state of the image, the type of signal source, the reduction of the dot pattern, etc. For example, the modulation cycle in the frame direction is set. Is an odd number, the AC drive cycle in the frame direction is controlled to be two frame cycles so that the signal voltage applied to each pixel is symmetrical with respect to the positive and negative sides. Can be solved.

Further, by emphasizing the degree of modulation according to the modulation amplitude of each gradation and performing compensation processing, it is possible to perform γ-modulation control with a predetermined amplitude even in a halftone section having a slow response speed. is there.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows the first aspect of the present invention.
1 to 3 are configuration block diagrams of a liquid crystal display device that performs a driving method according to the first embodiment based on the contents of FIGS. 1 to 3. In the liquid crystal display device of FIG. An RGB independent γ conversion circuit capable of individually setting a plurality of γ characteristics for converting the characteristics into a required predetermined applied voltage for each RGB. Reference numeral 2 denotes a predetermined pixel so as to obtain a desired viewing angle characteristic. RG with pattern
B is a γ switching circuit that performs switching control independently, and 3 is an optimum pattern while managing and controlling the voltage and polarity applied to the liquid crystal pixels, and sets γ data for the RGB independent γ conversion circuit and switches for the γ switching circuit. Control
A first view angle adaptive control circuit 3 configured to control the modulation of γ, 4 is an AC control unit capable of controlling the AC drive cycle of the liquid crystal panel, and 5 is a TN.
It is a liquid crystal panel in which the alignment is controlled by the liquid crystal so that the viewing angle dependence becomes large in a desired direction.

The operation of the liquid crystal display device configured as described above will be described with reference to FIGS. 1, 4, and 11.

First, the operation of each circuit will be described.

The RGB independent γ conversion circuit 1 has RGB3 systems of circuits for performing γ conversion processing by a calculation method using a plurality of parameters or a ROM table method, and each parameter can be set to γ1 and γ2 for each RGB. Has become.

The γ switching circuit 2 is a selector for switching between the γ1 characteristic and the γ2 characteristic as the γ conversion processing. The signal output from the γ switching circuit 2 is input to the liquid crystal panel 5, and is input to the source driver of the liquid crystal panel 5 through a polarity reversing circuit (not shown) or the like to drive the liquid crystal pixels.

Here, in the case of a normal liquid crystal panel, the source drive circuit and the gate drive circuit are inverted in polarity at a cycle prescribed to perform a predetermined alternating current, and an alternating current drive operation is performed. That is, the source drive circuit and the gate drive circuit operate such that the polarities are inverted every line if the liquid crystal panel is in the line inversion drive system and every dot in the dot inversion system, and so on. With respect to the frame direction, the polarity inversion operation is normally performed for each frame.

The alternating current control unit 4 is adapted to control the alternating current polarity to the source drive circuit and the gate drive circuit as required by appropriately changing the alternating current cycle.

The first viewing angle adaptive control circuit 3 and the γ switching circuit 2 and the RG switch the space between the γ1 characteristic and the γ2 characteristic in space-time.
The B independent γ conversion circuit 1 operates so as to control the γ1 and γ2 parameters and the switching pattern.
The modulation (switching) pattern and the γ characteristic setting are adaptively and optimally controlled so that the viewing angle enlarging process can be effectively performed with little adverse effect on the image quality.

Next, the processing performed in this embodiment will be described by taking the modulation pattern of the conventional example as an example.

First, in the first viewing angle adaptive control circuit 3, as shown in FIG. 4, the time direction modulation (in the frame direction) is performed as a modulation pattern in consideration of the state of the image and the desired viewing angle improving effect and adverse effect. It is assumed that a pattern is selected such that γ1 and γ2 can be switched every three frames with a switching period of n = 3.

In this case, regarding a certain pixel of interest, γ1 +, γ1-, γ1 +, γ2-, in order in the frame direction.
γ2 +, γ2-, γ1 +, γ1-, γ1 +, γ2-, γ
2+, γ2-. ． ． ． ． ． , For its neighboring pixels, γ
1-, γ1 +, γ1-, γ2 +, γ2-, γ2 +, γ1
-, Γ1 +, γ1-, γ2 +, γ2-, γ2
+. ． ． ． ． ． Becomes Since γ1 and γ2 are set to different γ values, if γ1> γ2, the former pixel will have a DC voltage component corresponding to + (γ1-γ2) every six frames, and the latter pixel will have an average value. Every 6 frames-
A DC voltage component corresponding to (γ1-γ2) will remain.

As described above, in the case where deviation occurs due to the balance between the frame inversion period of the modulation pattern and the AC driving period, this example will be explained. As shown in FIG. 11, n = 2. The modulation pattern period is changed, or n + 2, n + 5, n + 8, n + 11. ． ． ． ． ． No modulation is performed on the frame (that is, γ1 = γ
2), or by controlling the alternating current cycle as described in detail in the second embodiment, the management control can be performed so that the voltages are applied in positive and negative symmetry. It is characterized by having done.

The liquid crystal display device according to the present embodiment is configured as described above, so that the first viewing angle adaptive control circuit 3 can control the γ
When the modulation (switching) pattern is changed appropriately, it is controlled so that positive and negative asymmetric voltages are not applied to each liquid crystal pixel in consideration of the alternating current driving state. To control the
In the case where the modulation pattern cannot be changed due to the effect or the adverse effect, the alternating current control unit 4 is controlled to change the alternating current cycle so that positive and negative symmetrical voltages are always applied to the liquid crystal pixels and the direct current component is generated. The voltage is controlled so that it does not remain.

In the present embodiment, the balance between the modulation pattern in the frame direction and the alternating period in the frame direction has been described. However, the modulation pattern in the two-dimensional direction in the frame, line inversion, and dot Similar problems can be considered in the balance with the alternating methods such as inversion and column inversion, and it is also possible to change the modulation pattern or the alternating pattern by the same concept. However, since it is easier to appropriately correspond the modulation pattern, the modulation pattern is used in this embodiment.

As described above, when the modulation pattern of the γ characteristic is set in the first view angle adaptive control circuit 3, the pattern is controlled while being controlled so that the positive and negative asymmetric voltages are not applied to the liquid crystal pixels. It is possible to avoid the DC component remaining in the liquid crystal pixels by adopting a configuration that determines the value or controls the AC drive, and is stable and highly reliable view angle expansion control. Can be realized.

(Second Embodiment) A method of driving a liquid crystal display device according to a second embodiment based on the contents of claims 2 and 3 of the present invention will be described with reference to FIGS. 2 and 5.

In the first embodiment, an example of a modulation cycle n = 3 in the frame direction (the example of n = 3 in FIG. 4 has been described in the conventional example, so the dot inversion method and RGB trio unit modulation are illustrated). However, in practice, if the degree of modulation of γ is increased to some extent to obtain the effect of improving the viewing angle, flicker is likely to occur as described in the section of the problem to be solved by the invention. A shorter modulation period in the frame direction is advantageous. Although it depends on the setting state of the degree of modulation, the characteristics such as the speed and color and gradation of the displayed image, or the characteristics of the liquid crystal panel to be displayed, flicker becomes conspicuous when n ≧ 2. In other words, in this example, conversely, there is no solution other than n = 1 for the modulation period in the frame direction.

In this case, if the frame-direction alternating cycle is a normal one frame, as shown in FIG. 5 as described in the section of the problem to be solved by the invention, as shown in FIG. Γ1 +, γ2 in order in the frame direction
−, Γ1 +, γ2-, γ1 +, γ2-. ． ． ． ． ． , Γ2 +, γ1-, γ2 +, γ1 in the case of the adjacent pixel
−, Γ2 +, γ1-. ． ． ． ． ． Since γ1 and γ2 are set to different γ values, if γ1> γ2, a positive DC voltage is always applied to the former pixel and a negative DC voltage is always applied to the latter pixel. It will be.
However, when n ≧ 2, there is a problem of flicker, so
The modulation pattern cannot be changed as in the first embodiment.

Therefore, for the alternating current control unit 4, the alternating current cycle in the frame direction is +, +,-,-, +, +,-,
−. ． ． ． ． ． As described above, the control is performed so that the alternating current is performed every two frames. As a result, as shown in FIG. 2, for a certain pixel of interest, γ1 + and γ2 are sequentially arranged in the frame direction.
+, Γ1-, γ2-, γ1 +, γ2 +, γ1-, γ2
−. ． ． ． ． ． , Γ2 +, γ1 for the adjacent pixels
+, Γ2-, γ1-, γ2 +, γ1 +, γ2-, γ1
−. ． ． ． ． ． Therefore, even if γ1 and γ2 are different from each other, γ1 and γ2 are symmetrical with respect to each other in a constant cycle, and the driving is not such that reliability of the liquid crystal pixel is deteriorated.

Although it has been described that flicker starts to stand out at a modulation cycle of n ≧ 2, n ≧≧ depending on the image and various conditions.
In some cases, even 2 is not a problem. Thus, if n is an even number, the frame-direction AC conversion cycle may be set to every 1 frame as usual, and if n is an odd number as described above, if the AC conversion cycle is set to every 2 frames, a predetermined value is obtained. The positive and negative symmetry (4 frame periods in the above example) occurs during the frame period of, and the DC component does not remain, and highly reliable driving is possible.

As described above, when the frame modulation cycle is an odd number, the alternating cycle is set to every two frames, and when the frame modulation cycle is an even number, the alternating cycle is controlled to be every one frame as in the conventional case. The view angle enlargement control can be realized by the stable and highly reliable drive that does not cause the adverse effects such as the above.

(Embodiment 3) FIG. 3 shows claim 4 of the present invention.
5 is a configuration block diagram of a liquid crystal display device that performs a driving method according to a third embodiment based on the contents of FIG. 3, and in the present liquid crystal display device of FIG. 3, 1 is an RGB independent γ conversion circuit similar to that of the first embodiment, Reference numeral 2 denotes a γ switching circuit similar to that of the first embodiment, 31 denotes γ data setting for the RGB independent γ conversion circuit 1 and switching control for the γ switching circuit 2 while controlling the modulation degree according to the response speed data. A second viewing angle adaptive control circuit configured to perform γ modulation control, 4 is an AC control unit similar to that of the first embodiment, and 5 is a liquid crystal panel similar to that of the first embodiment. Is.

The operation of the driving method of the present embodiment in the liquid crystal display device configured as described above will be described with reference to FIGS. 3, 6, 7, 8 and 9.

In the first and second embodiments, an example of performing modulation control in the frame direction has been shown. As described in the section of the problem to be solved by the invention, this processing for modulating in the frame direction reduces various adverse effects on the image quality due to the conspicuous dot pattern due to the γ modulation processing, and reduces the viewing angle. This is performed for the purpose of reducing the discomfort of the appearance when the enlargement processing is performed.

However, in the case where γ is modulated in the frame direction in this way, a plurality of γ characteristics γ1 and γ to be modulated are to be modulated.
2 depends on the item of the viewing angle characteristic to be improved, the degree of improvement, etc., but is usually set so that the difference becomes large especially in the halftone level as shown in a and b in FIG. Many. However, in the case of the TN liquid crystal to which the present technology is applied, the response speed of the liquid crystal at the halftone level is generally slower than that at the white or black level.

Therefore, the modulation rate may not catch up with the frame period. That is, the degree of modulation (γ1, γ2
6), the predetermined amplitude (γ1-γ2) of each gradation may not be swung out. Explaining with reference to FIG. 9, the solid line “γ1,
When it is desired to obtain the "γ2 expected value" characteristic, even if the corresponding γ setting is made, the actual amplitude can only vary by the dotted "γ1, γ2 actual" characteristic.

As a result, the original effect of improving the viewing angle itself may not be sufficiently obtained.

As a result, the equivalent γ characteristic at the time of modulation (equivalent γ characteristic equivalent to a combination of γ1 and γ2) is biased as shown in FIG. The γ characteristic may not be a desired characteristic as shown by b in FIG.

For this reason, when the modulation is performed in the frame direction, the desired modulation cannot be performed and the degree of improvement in the viewing angle characteristics is reduced as compared with the case where the modulation is not performed in the frame direction. There is a problem that the visual characteristics may change from the intended characteristics.

However, since the response speed of the liquid crystal varies depending on the temperature and the like, the response speed data in consideration of these is input to the second view angle adaptive control circuit 31.

In the present embodiment, when the modulation control is performed in the frame direction and the modulation period in which the modulation degree of γ is equal to or greater than a predetermined value is short such as n = 1, the response speed data has a gradation value equal to or greater than a predetermined value. In the part, as shown in FIG. 8, RGB independent γ
Compensation operation is performed for the γ data setting for the conversion circuit 1 so as to emphasize the modulation degree according to the response speed data.
As a result, the γ modulation in the halftone is represented by the chain line “γ1,
As a result, “γ2 emphasis” occurs, and the overdrive operation is performed. As a result, a desired desired modulation amplitude (“γ1, γ2 expected value” indicated by the solid line in FIG. 9) can be secured. As described above, even when the modulation operation is performed in the frame direction in a short cycle, the required characteristics can be obtained and the effect of improving the viewing angle can be sufficiently obtained.

As described above, the dot pattern is reduced by adaptively controlling the degree of modulation in order to deal with such a problem that cannot be ignored in the halftone that is important in the processing when performing the modulation in the frame direction. However, the effect of improving the viewing angle can be effectively obtained even when the frame direction modulation is performed to suppress the adverse effect, and the viewing angle without a sense of discomfort does not significantly change the image quality from the front viewing angle direction from the original image quality. It will be possible to make improvements.

[0050]

As is apparent from the above description, according to the present invention, in the technique for improving the viewing angle characteristics by such signal processing and drive control, the improvement item and the state of the display image are adjusted according to the improvement item. Even if the optimum modulation pattern and modulation characteristics are set, the voltage will not be applied to the liquid crystal pixels asymmetrically, and this will reduce the occurrence of image sticking (image memory phenomenon) and flicker, It is possible to carry out stable and highly reliable driving without deteriorating.

Further, even when the display is performed by modulating in the frame direction to reduce the dot pattern associated with the processing so as to reduce the influence on the image quality, the appearance from the front viewing angle direction is not deteriorated without impairing the viewing angle improving effect. It is possible to realize effective view angle widening control that does not significantly change.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of a liquid crystal display device that performs a driving method according to first and second embodiments of the present invention.

FIG. 2 is a schematic diagram showing an example of a frame direction modulation pattern by a driving method according to a second embodiment of the present invention.

FIG. 3 is a configuration block diagram of a liquid crystal display device that performs a driving method according to a third embodiment of the present invention.

FIG. 4 is a schematic diagram showing an example of a frame-direction modulation pattern shown in a conventional example.

FIG. 5 is a schematic diagram showing an example of a frame-direction modulation pattern according to the driving method in the second embodiment of the present invention.

[FIG. 6] γ of a driving method according to a third embodiment of the present invention
It is a characteristic view which shows an example of control of the modulation degree in a conversion circuit.

FIG. 7: γ of the driving method according to the third embodiment of the present invention
It is a characteristic view which shows an example of a characteristic change by the response speed of (gamma) modulation control in a conversion circuit.

FIG. 8 is a characteristic diagram showing an example of a concept of γ modulation degree control in the second view angle adaptive control circuit 31 of the driving method according to the third embodiment of the present invention.

FIG. 9 is a schematic diagram illustrating the concept of response speed compensation processing of the driving method according to the third embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of a conventional liquid crystal display device.

FIG. 11 is a schematic diagram showing a switching pattern shown in a configuration of a liquid crystal display device of a conventional example.

FIG. 12 is a characteristic diagram showing a γ modulation characteristic of a conventional liquid crystal display device.

[Explanation of symbols]

1 RGB independent γ conversion circuit 2 γ switching circuit 3 First viewing angle adaptive control circuit 4 AC controller 5 LCD panel 31 Second viewing angle adaptive control circuit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 5/66 102 H04N 5/66 102B F term (reference) 2H093 NA31 NA51 NA61 NC13 NC14 ND01 ND12 ND13 NE07 5C006 AA11 AA22 AC26 AF46 BB11 BC16 BF24 FA23 FA38 FA55 5C058 AA09 BA02 BA09 BA13 BA30 BA31 BB06 BB09 5C080 AA10 BB05 CC03 DD01 DD06 EE29 EE30 FF12 JJ02 JJ05

Claims (4)

[Claims] 1. A method of driving a liquid crystal display device, comprising: RG
RGB in which B is independent and each has a plurality of γ conversion characteristics
An independent γ conversion circuit (1), a γ switching circuit (2) for switching the output of the RGB independent γ conversion circuit (1), and the R
The first viewing angle adaptive control circuit (3) for controlling the γ data setting of the GB independent γ conversion circuit (1) and the switching pattern of the γ switching circuit (2), and the alternating polarity of the signal voltage applied to the liquid crystal pixel are set. An alternating current control means (4) for controlling and a liquid crystal panel (5) are provided, and the signal voltage and the polarity applied to the liquid crystal pixel are managed from the relationship between the γ data setting, the switching pattern and the alternating current polarity. A method for driving a liquid crystal display device, wherein the γ data setting and the switching pattern or the alternating polarity are controlled so that a direct current component is not applied to liquid crystal pixels. 2. The first viewing angle adaptive control circuit (3) controls the γ switching pattern performed on the γ switching circuit (2) for every odd frame in the frame direction of the video signal. In this case, the method for driving a liquid crystal display device according to claim 1, wherein the alternating current control means (4) sets the alternating current frequency in the frame direction every two frames. 3. In the first viewing angle adaptive control circuit (3), the γ switching pattern performed for the γ switching circuit (2) is controlled to be switched frame by frame in the frame direction of the video signal. In this case, the alternating current control means (4)
2. The method of driving a liquid crystal display device according to claim 1, wherein the alternating frequency in the frame direction is set every two frames. 4. A method of driving a liquid crystal display device, comprising: RG
RGB in which B is independent and each has a plurality of γ conversion characteristics
An independent γ conversion circuit (1), a γ switching circuit (2) for switching the output of the RGB independent γ conversion circuit (1), and the R
A second viewing angle adaptive control circuit (31) for controlling the γ data setting of the GB independent γ conversion circuit (1) and the switching pattern of the γ switching circuit (2) according to the response speed data of the liquid crystal panel (5). , An alternating current control means (4) for controlling the alternating current polarity of the signal voltage applied to the liquid crystal pixel, and a liquid crystal panel (5), and the second viewing angle adaptive control circuit (31)
In the case of switching the γ switching pattern in the frame direction, the γ data setting is compensated for this decrease so that the modulation amount between γ to be switched does not decrease due to insufficient response speed of the liquid crystal panel that changes depending on gradation. A method for driving a liquid crystal display device, which comprises performing emphasis control as described above.