JPH08179734A - Liquid crystal display device, and driving circuit for liquid crystal display element - Google Patents

Abstract

PURPOSE: To provide a liquid crystal display device of double refraction control type in which a reduction in image quality by noise can be prevented. CONSTITUTION: An analog video signal is converted into a digital video data of n+1 bits by an A/D converter 14. A digital video data D3 for the previous frame stored in a frame memory 18 is compared with the digital video data D1. The output of the A/D converter 14 is selected by a selector 15 as a digital video data D2 for the present frame when the difference |D1-D3| is a prescribed value or more, the digital video data D3 for the previous frame read from the frame memory 18 is selected by the selector 15 and outputted when the difference |D1-D3| is less than the prescribed value, and the outputted data is also stored in the frame memory 18. A voltage corresponding to the upper n-bit of the output data of the selector 15 is applied to the corresponding picture element of a double refraction control type liquid crystal display element 11. A prescribed pattern data may be added to the output data of the A/D converter 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device for displaying a color according to an applied voltage and a drive circuit for a liquid crystal display element, and more particularly to a liquid crystal display device capable of reducing display disturbance and deterioration of image quality due to noise. The present invention relates to a drive circuit for a liquid crystal display device.

[0002]

2. Description of the Related Art As a liquid crystal display device capable of color display of a plurality of colors without using a color filter, a birefringence controlled system (Electrically Controlled Birifrengency system) is known. A birefringence control type liquid crystal display element is composed of a liquid crystal cell in which liquid crystal is sealed between a pair of substrates subjected to an alignment treatment, and two polarizing plates arranged so as to sandwich the liquid crystal cell. Is applied to change the molecular alignment of the liquid crystal to change the birefringence effect of the liquid crystal layer, and the change in the birefringence effect changes the spectral distribution of light transmitted through the liquid crystal cell to display a desired color.

The birefringence control type liquid crystal display element can display in color without using a color filter, and the display is bright. Therefore, there is an advantage that a reflective color liquid crystal display device can be realized and the structure of the liquid crystal display element is simple.

As a method of displaying a color image on a birefringence control type liquid crystal display element, as shown in FIG. 8, an analog video signal is converted into digital video data by an A / D converter 14, and this is converted into a voltage conversion table. 16 is used to convert the voltage data into an applied voltage, convert the voltage data into an applied voltage, and apply the applied voltage to each pixel of the birefringence control type liquid crystal display element.

[0005]

In the birefringence control type liquid crystal display element, similar colors do not necessarily correspond to voltages close to each other. For this reason, when noise is added to the voltage near the digitizing threshold, colors other than the colors displayed by the voltages on both sides of the threshold are displayed as noise, and the noise is very noticeable. For example, depending on the characteristics of the liquid crystal display element, noise may be added to a dark red signal to display a bright yellow signal. In this case, for example, when displaying dark red on a black background, noise causes bright yellow to be displayed on a black background,
The problem is that noise is very noticeable.

In order to solve such a problem, as shown in FIG. 9, a driving method has been proposed in which a cyclic low-pass filter is arranged in front of the voltage conversion table 16 to reduce noise. This cyclic low-pass filter is effective for a display element in which there is no jump in voltage value and color change. However, in a jumpy display device, even if a cyclic low-pass filter is provided, its output is only distributed to either above or below the threshold, and is affected by the same effect as when no filter is inserted.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid crystal display device and a drive circuit for a liquid crystal display element which are not easily affected by noise and can display a high quality image.

[0008]

In order to achieve the above-mentioned object, a liquid crystal display device according to a first aspect of the present invention has a plurality of pixels arranged in a matrix and responds to an applied voltage in pixel units. The liquid crystal display element that displays different colors and the video signal of the previous frame of each pixel and the video signal of the current frame are compared, and when both video signals differ by a predetermined level or more, the video signal of the current frame is selected and output. And a driving means for applying a voltage corresponding to the video signal output from the selecting / outputting means to a corresponding pixel of the liquid crystal display element.

A liquid crystal display device according to a second aspect of the present invention has a plurality of pixels arranged in a matrix, and a liquid crystal display element for displaying a color corresponding to an applied voltage in pixel units, and an image. Input means for inputting a signal, hysteresis adding means for giving a hysteresis to the video signal input by the input means between frames, and a voltage corresponding to the video signal to which the hysteresis is added by the hysteresis adding means is applied to the liquid crystal display element. Drive means for applying to the corresponding pixel of (1).

Further, a liquid crystal display device according to a third aspect of the present invention has a plurality of pixels arranged in a matrix, and a liquid crystal display element for displaying a color corresponding to an applied voltage in a pixel unit, and an image. Means for inputting a signal, adding means for adding a pattern signal of a predetermined pattern to the video signal, and applying a voltage corresponding to the video signal to which the pattern signal is added by the adding means to a corresponding pixel of the liquid crystal display element And a driving means.

The drive circuit according to the fourth aspect of the present invention compares the video signal of the previous frame of each pixel with the video signal of the current frame, and when both video signals differ by a predetermined level or more, the current frame A selection / output means for selecting and outputting the video signal of, and a driving means for applying a voltage corresponding to the video signal output from the selection / output means to a corresponding pixel of the liquid crystal display element. Characterize.

The drive circuit according to the fifth aspect of the present invention includes an input means for inputting a video signal, a hysteresis adding means for giving a hysteresis to the video signal input by the input means between frames, and the hysteresis circuit. Drive means for applying a voltage corresponding to the video signal to which the hysteresis has been added by the adding means to the corresponding pixel of the liquid crystal display element.

In the drive circuit according to the sixth aspect of the present invention, means for inputting a video signal, addition means for adding a pattern signal of a predetermined pattern to the video signal, and a pattern signal added by the addition means Drive means for applying a voltage corresponding to the generated video signal to the corresponding pixel of the liquid crystal display element.

[0014]

According to the inventions of the first and fourth aspects, since the video signal of the current frame is selected only when the difference between the video signal of the current frame and the video signal of the previous frame is equal to or more than a predetermined level, a minute noise is generated. The influence of noise can be removed when the level of the video signal is changed by being superimposed on the video signal.

According to the inventions of the second and fifth aspects,
Since the video signal is provided with hysteresis between frames, even if a minute noise is superposed on the video signal, it is ignored due to the hysteresis, and the influence of noise can be removed.

According to the inventions of the third and sixth aspects,
Since a regular pattern, that is, noise, is intentionally added to the video signal, a signal having a level near the threshold is displayed in a state in which a signal higher than the threshold and a signal lower than the threshold are mixed. Therefore, the intermediate color is displayed by the dither effect, and the influence of noise can be reduced.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A birefringence control type liquid crystal display device according to an embodiment of the present invention will be described below with reference to the drawings. FIG.
As shown in FIG. 1, this liquid crystal display device includes a birefringence control type liquid crystal display element 11, a row driver 12, and a column driver 1.
3, an A / D converter 14, a selector 15, a voltage conversion table 16, a comparator 17, and a frame memory 18
And a control unit 19.

As shown in FIG. 2, the liquid crystal display element 11 includes
A pair of transparent substrates 21 and 31 is provided. The substrate 21 has
The pixel electrode 23 and the TF whose source is connected to the pixel electrode 23
Ts (thin film transistors) 25 are arranged in a matrix, and each TFT 25 is connected to a gate line (scanning line) 27 and a data line (color signal line) 29.

Further, the substrate 21 is provided with an alignment film 40 on the pixel electrode 23 and the TFT 25 which has been subjected to a predetermined alignment treatment, and a polarizing plate 33 and a reflection plate 35 are provided on the back surface side thereof. There is.

A transparent counter electrode 38, which is opposed to each pixel electrode 23 and is applied with a predetermined voltage, is formed on the surface of the substrate 31 facing the substrate 21. An alignment film 39 that has been subjected to a predetermined alignment treatment is provided on the counter electrode 38.
A retardation plate 32 and a polarizing plate 34 are provided on the upper surface side of the substrate 31. The substrates 21 and 31 are joined via a frame-shaped sealing material (not shown). Between the substrates 21 and 31, for example, a nematic liquid crystal 36 having a positive dielectric anisotropy is used.
Are twist-oriented by the alignment films 39 and 40 and are encapsulated.

The alignment direction of the liquid crystal molecules on the substrate 31 is deviated from the alignment direction of the liquid crystal molecules on the substrate 21 by a predetermined angle, for example, in a predetermined direction when viewed from above, that is, from the observation side.
The liquid crystal molecules are 90 ° to 270 between the substrates 21 and 31.
° Twist orientation.

The transmission axis of the polarizing plate 34 and the transmission axis of the polarizing plate 33 are set with reference to the alignment direction of the liquid crystal molecules on the substrate 21. The slow axis of the retardation plate 32 is the polarizing plate 3
4 are arranged in a direction intersecting the transmission axis.

Incident light from the liquid crystal display element 11 is reflected by the polarizing plate 3
4, the phase difference plate 32, the liquid crystal 36, and the polarizing plate 33 in order, and is reflected by the reflecting plate 35.
The liquid crystal 36, the phase difference plate 32, and the polarizing plate 34 are sequentially emitted.

Linearly polarized light that has passed through the polarizing plate 34 becomes elliptically polarized light that differs for each wavelength light due to the birefringence effect in the process of passing through the retardation plate 32. This elliptically polarized liquid crystal 3
In the process of passing through 6, the polarization state is further changed by the birefringence effect and the light is emitted to the polarizing plate 33, and the polarizing plate 33 for each wavelength light is emitted.
Only the polarized light component in the transmission axis direction of is transmitted and reflected by the reflection plate 35.

The reflected light again undergoes birefringence in the process of sequentially passing through the polarizing plate 33, the liquid crystal 36, and the retardation plate 32 to change the polarization state, and then enters the polarizing plate 34 again. Polarizing plate 3
In the light incident on the light source 4, only the polarization component in the transmission axis direction is transmitted, and the light is colored according to the wavelength light having the transmitted polarization component. The birefringence effect of the liquid crystal 36 changes according to the voltage applied to the liquid crystal 36, and the spectral distribution of the emitted light differs depending on the difference in the birefringence effect. That is, the light emitted from the liquid crystal display element 11 is colored in a plurality of colors according to the voltage applied to the liquid crystal 36. The relationship between the applied voltage and the display color changes depending on the direction of the alignment treatment, the twist angle of the liquid crystal molecules, the arrangement of the polarizing plate and the retardation plate.

The A / D converter 14 converts an analog input signal (analog video signal) into an n + 1-bit digital video signal D1. Here, the bit number n is the liquid crystal display element 1
The number of bits of data for driving 1 is shown. That is, the A / D converter 14 A / D-converts the analog input signal with a bit number larger than the bit number of the data for driving the liquid crystal display element 11. The selector 15 outputs (n + 1) -bit digital video data D1 output from the A / D converter 14 and n of the previous frame of the same pixel supplied from the frame memory 18.
Upon receiving the + 1-bit digital video data D3, one of them is selected according to the selection signal S supplied from the comparator 17.

The voltage conversion table 16 stores, at each address position indicated by n-bit data, voltage data indicating a voltage to be applied to the corresponding pixel of the liquid crystal display element 11 in order to display the color indicated by the data. Then, the voltage data corresponding to the supplied n-bit address data is output. FIG. 3 shows an example of the voltage conversion table 16 when n = 3.

The comparator 17 compares the n + 1-bit digital video data D1 output from the A / D converter 14 with the digital video data D3 of the previous frame of the same pixel output from the frame memory 18, and compares the two data. Absolute value of |
If D1-D3 | is a predetermined value or more, the digital video data D1 is selected, and if the absolute value of the difference | D1-D3 | is less than the predetermined value, the digital video data D3 is selected. Output S. The selector 15 described above selects one of the digital video data indicated by the selection signal S. Therefore, the digital video data D1 of the current frame is displayed only when the digital video data D1 of the current frame changes from the digital video data D3 of the previous frame stored in the frame memory 18 by a predetermined level or more, and in other cases. Means that the digital video data D1 of the current frame is ignored and the digital video data D3 of the previous frame is displayed.

The frame memory 18 has a capacity of storing (n + 1) -bit digital video data D2 for one frame, stores the digital video data D2, and stores the stored digital video data D2 in the next frame period. The data D3 is supplied to the selector 15 and the comparator 17. The control unit 19 uses the A / D converter 14
It controls the operation of the entire noise reduction circuit including the A / D conversion timing, the address of the frame memory 18 and the control of reading / writing.

The column driver 13 has a shift register for taking in the voltage data supplied from the voltage conversion table 16,
A driver circuit that supplies a voltage signal (writing voltage) corresponding to the voltage data for one horizontal scanning period held in the shift register to the corresponding data line 29.

The row driver 12 sequentially applies a gate pulse to the gate line 27. The TFT 25 connected to the gate line 27 to which the gate pulse is applied is turned on, and the voltage of the data line 29 is applied to the pixel electrode 23 connected to the turned on TFT 25. The row driver 12
The gate pulse is turned off immediately before the voltage applied to the data line 29 is switched. Then, the TFT 25 is turned off, and the pixel electrode 23, the counter electrode 38, and the liquid crystal 36 between them.
The voltage applied up to that time is held in the pixel capacitance formed by, and a color corresponding to this voltage is displayed.

Next, the operation of this circuit will be described with reference to FIGS. Here, for easy understanding, n = 3
And The A / D converter 14 converts the analog video signal into 4-bit (n + 1 bit) digital video data D1 at a predetermined sampling frequency. At this time, the frame memory 18 reads the digital video data D3 of the previous frame of the corresponding pixel under the control of the control unit 19,
It is supplied to the selector 15 and the comparator 17.

The comparator 17 obtains the difference | D1-D3 |, and when the value is equal to or greater than a predetermined value, it outputs a selection signal S to select the digital video data D1. The selector 15 indicates by the selection signal S. Selected data and output. Here, for example, the predetermined value is "0010", and the digital image data D1 and D3 are "1011" and "101", respectively.
When set to 0 ", the value of | D1-D3 |
1), which is smaller than the predetermined value “0010”.
The selector 15 selects and outputs D3 "1010".
When D1 is "1011" and D3 is "1101" or "1001", the value of | D1-D3 | is "0".
010 ″, and the selector 15 selects and outputs D1.

Under the control of the control unit 19, the frame memory 18 stores the 4-bit digital video data D2 selected and output by the selector 15 at the corresponding address position. At the same time, the voltage conversion table 16 is addressed by the upper 3 bits of the digital video data D2 and outputs the corresponding voltage data. For example, when the digital video data D2 is "0101", the voltage data "000" corresponding to the upper 3 bits "010" is output. This voltage data indicates a write voltage to be applied to each pixel of the liquid crystal display element 11 in order to display the color represented by the video data "010".

The column driver 13 takes in the voltage data supplied from the voltage conversion table 16 while shifting it. In the next horizontal scanning period, the column driver 13 supplies the driving voltage corresponding to the fetched voltage data for one scanning line to the corresponding data line 29.

Each drive voltage is at the time the row driver 12
Gate line 27 to which the gate pulse is applied by
It is applied to the pixel electrode 23 through the TFT 25 connected to the pixel electrode 23. When the gate pulse is turned off, the TFT 25 is also turned off, and the pixel capacitor formed by the pixel electrode 23, the counter electrode 38, and the liquid crystal 36 between them holds the driving voltage that has been applied until then, and the color corresponding to this voltage is changed. Is displayed.

In this way, the difference between the digital video data D1 of the current frame and the digital video data D3 of the previous frame is obtained for each pixel, and the digital video data D1 of the current frame is selected only when the difference is a predetermined value or more. If the difference is less than the predetermined value, the digital video data D3 of the previous frame is selected and display is performed using only the upper bits of the selected data. In other words, the input video signal has hysteresis between frames. Therefore, small levels of variation and noise are ignored. As a result, minute noises on the signal near the threshold (the level for switching the display color) are removed, and the adverse effect on the display is removed.
As a result, it is possible to prevent a color other than the color displayed by the voltage above and below the threshold level from being displayed due to noise.

In the configuration of FIG. 1, the absolute value of the difference between the digital video data D1 and D3 is obtained by the comparator 17,
One of the digital video data D1 and D3 is selected from the value and outputted, but other configurations may be adopted if similar results are obtained. For example, as shown in FIG. 4, video data D1 or D3 to be selected at each storage position whose address is concatenated data of digital video data D1 and D3.
The current frame data generation table 51 storing one of the two may be used.

An example of the current frame data generation table 51 when n = 3 is shown in FIG. As shown in the figure, for example, when the digital video data D1 is "1011",
Is “1010”, the difference between the two is less than “0010” at the storage position of the address “10111010” in the current frame data generation table 51, so “1010” equal to D3 is set as the digital video data D2. Store. With such a configuration, it is not necessary to obtain the difference of | D1−D3 |, higher speed operation is possible, and control is easier.

In the above embodiment, noise superimposed on the analog video signal may cause a color different from the original display color to be displayed as a cluster in a relatively wide range.
This problem can be reduced by intentionally adding minute noise to the video signal and displaying an intermediate color due to the dither effect.

FIG. 6 shows a circuit configuration for enabling such driving. In the configuration of FIG. 6, an adder 52 is arranged at the subsequent stage of the A / D converter 14, and the A / D converted digital video data and the regular pattern supplied from the regular pattern generating circuit 53 are added, and the added value is calculated. The selector 15 and the comparator 17 shown in FIG. 1 as the digital video data D1.
Alternatively, it is supplied to the current frame data generation table 51 shown in FIG. Similar to the above-described embodiment, when n = 3, for example, the regular pattern generation circuit 53 alternately generates pattern data “0001” and “−0001” in pixel units and supplies the pattern data to the adder 52. The adder 52 adds the 4-bit digital video data supplied from the A / D converter 14 and the pattern data to obtain the current frame video data D.
Output as 1. Adding the regular pattern is equivalent to changing the threshold, which is the reference level for switching the applied voltage, for each pixel.

In this case, if expressed in analog, as shown in FIG. 7, regular noise is superimposed on the video signal. Therefore, when an analog video signal having a voltage near the threshold is A / D converted, a display color corresponding to a voltage equal to or lower than the threshold and a display color corresponding to a voltage equal to or higher than the threshold are alternately displayed. The color mixture is recognized. Therefore, even if the minute noise is superposed on the analog video signal, its influence is reduced.

Although the regular pattern is added to the signal after A / D conversion in FIG. 7, an analog regular pattern may be added to the input analog video signal.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the data D1 to D3
Was A / D-converted with a bit number larger than the driving bit number n by 1 bit, but the A / D conversion was performed with an arbitrary bit number m larger than the driving bit number n. It can be carried out. Further, the number of bits n used for driving the liquid crystal display element 11 and the number of bits of the voltage data output from the voltage conversion table 16 do not need to be equal.
May be different. The predetermined value for setting whether to select the digital video data of the previous frame or the video data of the current frame can be set arbitrarily.

The liquid crystal display element 11 in the above embodiment is
A nematic liquid crystal having a positive dielectric anisotropy was twisted and used in the liquid crystal cell. However, the configuration of the birefringence control system of the present invention is arbitrary, and for example, the vertical molecular array (DA
Various display elements such as P) type, parallel molecular alignment (homogeneous) type, hybrid molecular alignment (HAN) type, and liquid crystal alignment mode type can be used. Further, the retardation plate may be omitted as appropriate. The present invention can also be applied to a transmissive liquid crystal display element.

[0046]

As described above, according to the present invention, it is possible to display a high quality image by removing the minute noise included in the video signal.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a liquid crystal display element according to an embodiment of the present invention.

FIG. 3 is a diagram showing an example of a voltage conversion table.

FIG. 4 is a circuit diagram showing a modified example of the circuit shown in FIG.

5 is a diagram showing an example of a current frame data generation table shown in FIG.

6 is a diagram showing an example of a circuit added to the circuits shown in FIGS. 1 and 4. FIG.

FIG. 7 is a diagram for explaining the effect of the circuit shown in FIG.

FIG. 8 is a circuit diagram showing an example of a conventional drive circuit.

FIG. 9 is a circuit diagram showing an example of a conventional drive circuit in which a cyclic low-pass filter is arranged in the subsequent stage of the table shown in FIG. 8 to reduce noise.

[Explanation of symbols]

11 ... Liquid crystal display element, 12 ... Row driver, 13 ... Column driver, 14 ... A / D converter, 15 ... Selector, 1
6 ... Voltage conversion table, 17 ... Comparator, 18 ... Frame memory, 19 ... Control unit, 21 ... Substrate, 23 ... Pixel electrode, 25 ... TFT (thin film transistor) 27 ...
Gate line, 29 ... Data line, 31 ... Substrate, 3
2 ... Retardation plate, 33 ... Polarizing plate, 34 ... Polarizing plate, 35 ...
..Reflector, 36 ... Liquid crystal, 38 ... Counter electrode, 39 ... Alignment film, 40 ... Alignment film, 51 ... Current frame data generation table, 52 ... Adder, 53 ... ..Regular pattern generation circuits

Claims (13)

[Claims] 1. A liquid crystal display element having a plurality of pixels arranged in a matrix and displaying a color corresponding to an applied voltage in pixel units, a video signal of a previous frame and a video signal of a current frame of each pixel. And when both video signals differ by a predetermined level or more, a selection / output means for selecting and outputting the video signal of the current frame, and a voltage corresponding to the video signal output from the selection / output means for the liquid crystal A liquid crystal display device comprising: a driving unit that applies a voltage to a corresponding pixel of a display element. 2. The A / D converter for converting the analog video signal into a digital video signal.
D conversion means, storage means for storing video signals for at least one frame, digital video signals output from the A / D conversion means and digital video signals of previous frames stored in the storage means are compared. , A selection for outputting the digital video signal output from the A / D conversion means when the difference is a predetermined value or more, and outputting the digital video signal of the previous frame read from the storage means when the difference is less than the predetermined value Means and storage means for storing the output data of the selecting means in the storage means for processing the next frame, wherein the driving means supplies a voltage corresponding to the output of the selecting means to the liquid crystal display element. The liquid crystal display device according to claim 1, further comprising means for applying to each of the pixels. 3. The selection means compares the digital video signal output from the A / D conversion means with the digital video signal of the previous frame stored in the storage means, and whether the difference is a predetermined value or more. Comparing means for outputting a selection signal indicating whether or not, one of the digital video signal output from the A / D conversion means and the digital video signal of the previous frame read from the storage means is output according to the selection signal. The liquid crystal display device according to claim 2, further comprising: 4. The selecting means selects to an address position indicated by connection data of the digital video signal output from the A / D converting means and the digital video signal of the previous frame stored in the storage means. The liquid crystal display device according to claim 2, wherein the liquid crystal display device comprises a table storing power data. 5. The driving means applies a voltage corresponding to at least upper bits of the output data of the selecting / output means except for the least significant bit to each pixel. The liquid crystal display device according to item 1. 6. The number of bits of the output data of the A / D conversion means and the storage data of the storage means is larger than the number of bits of the data for driving the liquid crystal display element by the driving means. Item 4. The liquid crystal display device according to item 2, 3 or 4. 7. The liquid crystal display device according to claim 2, further comprising means for adding a predetermined pattern of data to the output data of the A / D conversion means. 8. The liquid crystal display device according to claim 1, further comprising means for adding a signal of a predetermined pattern to the input video signal. 9. A liquid crystal display element having a plurality of pixels arranged in a matrix and displaying a color corresponding to an applied voltage in pixel units, input means for inputting a video signal, and input by the input means. And a driving means for applying a voltage corresponding to the video signal to which the hysteresis is added by the hysteresis adding means to a corresponding pixel of the liquid crystal display element. A liquid crystal display device characterized by the above. 10. A liquid crystal display element having a plurality of pixels arranged in a matrix and displaying a color according to an applied voltage in pixel units, means for inputting a video signal, and a predetermined pattern for the video signal. A liquid crystal device comprising: an addition unit that adds a pattern signal; and a drive unit that applies a voltage corresponding to the video signal to which the pattern signal is added by the addition unit to a corresponding pixel of the liquid crystal display element. Display device. 11. A selection / output means for comparing the video signal of the previous frame of each pixel with the video signal of the current frame, and selecting and outputting the video signal of the current frame when both video signals differ by a predetermined level or more. And a driving means for applying a voltage corresponding to the video signal output from the selecting / outputting means to a corresponding pixel of the liquid crystal display element, the driving circuit for the liquid crystal display element. 12. An input means for inputting a video signal, a hysteresis adding means for giving a hysteresis to the video signal input by the input means between frames, and a video signal to which hysteresis is added by the hysteresis adding means. A driving circuit for a liquid crystal display element, comprising: a driving unit that applies a voltage to a corresponding pixel of the liquid crystal display element. 13. A liquid crystal display device comprising: means for inputting a video signal; addition means for adding a pattern signal of a predetermined pattern to the video signal; and a voltage corresponding to the video signal to which the pattern signal is added by the addition means. 2. A liquid crystal display device, comprising: a driving unit that applies the voltage to the corresponding pixel.