JPH08221039A - Liquid crystal display device and its driving method - Google Patents

Abstract

PURPOSE: To provide a liquid crystal display device and its driving method which can display a picture with natural picture quality as a CRT by improving a driving method of a full line liquid crystal display device. CONSTITUTION: A liquid crystal display device 100 is constituted of an input terminal 2, a decoder 3 converting an input signal into RGB signals, a signal driver 24 generating a refresh signal 31 as well as a video signal 5 and common voltage 6, a TG 28 generating a control signal 27 including a refresh control pulse RF and a frame pulse, and a liquid crystal panel 20. A refresh signal applying means 30 commonly connected to a signal line 24 connected to a H scanner 21 is specifically provided in the liquid crystal panel 20. Thereby, since an interlaced line of an interlace system written in a previous field is refreshed, a picture of natural picture quality having no after image can be displayed.

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 used in equipment with a liquid crystal monitor, a liquid crystal projector, etc., and a driving method therefor. More specifically, the driving method for a full line liquid crystal display device with high resolution is improved. The present invention relates to a liquid crystal display device and a driving method thereof.

[0002]

2. Description of the Related Art In recent years, with the spread of equipment with a liquid crystal display and equipment with a liquid crystal display represented by a liquid crystal projector, there has been an increasing demand for higher performance of the liquid crystal display, resulting in higher resolution and higher image quality of the liquid crystal display. Is progressing. Under these circumstances, the liquid crystal display device has been improved in resolution mainly in a large-sized liquid crystal panel and a liquid crystal panel for a liquid crystal projector that displays an image enlarged several tens of times, and the number of effective scanning lines is approximately 480. A full-line liquid crystal display device equipped with it is now available.

On the other hand, an interlaced scanning system (hereinafter simply referred to as "interlace") is used as a scanning system for a general television receiver.
It is adopted). When reproducing such a television signal (video signal) in the above-mentioned full line liquid crystal display device, an interlace signal is converted into a progressive scanning method (hereinafter simply referred to as "non-interlace") and displayed. There is a need. In other words, the driving method of the liquid crystal display device is AC driving in principle, and since the above-described full-line liquid crystal display device has approximately 480 effective scanning lines, the scanning lines that do not exist in the interlaced signal are generated and the AC driving is performed. This is because it needs to be driven. The present invention relates to a method of driving a full-line liquid crystal display device by an interlace system like a general television receiver, and the configuration example will be described below.

A conventional liquid crystal display device and its driving method will be described with reference to FIG.

In FIG. 6, reference numeral 1 indicates a conventional liquid crystal display device. The conventional liquid crystal display device 1 includes an input terminal 2 to which a signal of an interlace system or the like is input, a decoder 3 for converting the input signal into separate signals of R, G, B, a signal driver 4, and the signal driver 4. Generated video signals 5 such as R, G and B, and C which is a common electrode
The common voltage 6 applied to the OM electrode, the control signal 7 such as (HST, HCK, VST, VCK) and ENB (enable signal, hereinafter simply referred to as “ENB”) necessary for controlling the liquid crystal panel described later and the signal. A timing generator (hereinafter simply referred to as "TG") 8 for outputting a frame pulse FRP for video signal inversion to the driver 4, and a color or monochrome liquid crystal panel 1 for displaying an image.
It is roughly composed of zero.

The detailed structure of the liquid crystal panel 10 includes an H scanner 11 mainly composed of a sample hold and a shift register.
Alternatively, a V scanner 12 is inserted, a signal line 14 is connected to the H scanner 11 via a switching device 13, and a scanning line (hereinafter simply referred to as “line”) 15 is connected to the V scanner 12. These are arranged in a matrix. Further, the line 15 has a gate G,
A thin film transistor (TFT) (hereinafter, simply referred to as “T”) is connected to the signal line 14 via the source / drain SD.
16) is connected. The TFT 16
The storage capacitor Cs and the liquid crystal cell LC are formed between the common electrode 6 and the COM electrode 17 connected to the common voltage 6.

The operation of the conventional liquid crystal display device having the above structure will be described. A signal such as a composite video input to the input terminal 2 in FIG. 6 is input to the decoder 3. The decoder 3 converts signals such as composite video into R, G, and B separate signals suitable for driving the liquid crystal panel 10, and performs color, picture, and
An adjustment circuit (not shown) such as a hue (hue) is added and sent to the signal driver 4 in the next stage. In the signal driver 4, when the next liquid crystal panel is color, R,
In the case of monochrome, each of the G and B video signals 5 is converted into an AC signal based on the frame pulse FRP and output. Similarly, the common voltage 6 which is, for example, a DC voltage is generated and output to the liquid crystal panel 10.

In the TG 8, various control signals 7 used for controlling the liquid crystal panel 10 are supplied to a VCO (Voltage Controlled).
Oscillator), H-Sync, V-Sync (synchronization signal), and output to the liquid crystal panel 10 in the next stage. These control signals are specifically HST, HCK, VST, VCK and EN.
BST and the like, and the operation thereof will be described. HST is a start pulse for the shift register of the H scanner 11, HCK is a clock pulse for driving the shift register, and the horizontal shift register is based on the HST. Thus, the signal lines 14 are sequentially selected. Similarly, VST and VCK are a start pulse and a clock pulse for the V scanner 12, and ENB is capable of selecting a predetermined line in association with the V scanner 12. In other words, when different broadcasting systems are used, for example, NTSC and PAL are also displayed on the same liquid crystal panel, this ENB
Is used for thinning out as "low level" (low active).

The liquid crystal panel 10 receives the video signals 5 such as R, G and B input from the above-mentioned circuit, the common voltage 6 and H.
The control signal 7 such as ST, VST and ENB is received and supplied to the H scanner 11 and the V scanner 12. TF
At T16, in response to the selection pulse supplied from the line 15 connected to the V scanner 12, the video signal 5 is taken in via the signal line 14 via the switching device 13 connected to the H scanner 11. The captured video signal 5 is supplied to the storage capacitor CS and the liquid crystal cell LC. In the liquid crystal cell LC, liquid crystal molecules (not shown) are twisted and inverted in the applied voltage direction by a video voltage supplied according to the video level of each pixel, and a liquid crystal panel is utilized by utilizing the optical rotatory power of the liquid crystal molecules and the polarizing plate. 10 images are displayed.

The following two methods are known as a method of displaying a full-line image on such a conventional liquid crystal display device 1. One of them is a double speed conversion method in which a double speed video signal is generated by a frame memory or other means and a time axis is operated to convert a frame frequency into a frequency region where flicker does not occur. This method includes a line interpolation method that utilizes line correlation between adjacent lines in a field, a field interpolation method that combines field images, and a motion adaptive interpolation method that combines these. . This motion-adaptive interpolation method is a field interpolation method that detects motion signals based on frame differences in a motion detection circuit, and is capable of complete scanning line interpolation for still images, and lines with little motion blur for moving images. The interpolation method is switched in pixel units.
However, each of these drive methods requires significant addition of hardware, and the image quality is 2
There is a problem that a double image (ghost) is visible.

The two are general CRT (CRT).
Similar to the display method described above, the liquid crystal panel is driven by the interlace system. That is, an odd field video signal is applied to the odd (Odd) lines of the liquid crystal panel 10, and an even field video signal is applied to the even (Even) lines, and the composite video is displayed as a frame on the liquid crystal panel. To do. In this case, in the field where even (odd) lines are scanned, the video signals of odd (even) lines hold the video signals written in the previous field.

[0012]

However, in the double speed conversion system, which is one of the driving methods of the liquid crystal display device of the prior art,
This is a method of operating the time axis with a frame memory or other means to convert the frame frequency into a frequency range where flicker does not occur.This drive method requires not only significant addition of hardware but also image quality in moving images. There is a problem that a double image (ghost) is visible behind the object.

In the second method of driving the liquid crystal display device by the interlace system, the liquid crystal display device is divided into an odd field and an even field, and a video signal for each field is applied. The video signal displayed in the specific field in this case means that the video signal of the odd (even) line holds the video signal of the previous field in the field in which the even (odd) line is scanned. This means that line flicker is reduced and vertical resolution is improved in still images, and in moving images, the video signal of the previous field is held for a long time to form an afterimage, which causes a remarkable deterioration in image quality. It was Furthermore, when a new video signal is written in the part that was white (or black) in the previous frame, there is a problem that the contrast is reduced due to integration in the time direction,
It has been difficult for a conventional liquid crystal display device to display an interlaced signal with a natural image quality like a CRT.

The present invention has been made in consideration of the above points, and a large addition of hardware in a double speed conversion system which is a drive system of a full line liquid crystal display device, a residual image of a moving image in an interlace system, etc. An object of the present invention is to provide a liquid crystal display device which improves image quality deterioration and displays a full-line liquid crystal display device with a natural image quality like a CRT, and a driving method thereof.

[0015]

In order to solve the above problems, in a liquid crystal display device for interlace driving a full line liquid crystal display device of the present invention, a signal driver for generating a refresh signal, a control signal and an enable signal, A timing generator that generates a refresh control pulse, an H scanner that is connected to a signal line, a scanning line that is connected, and a V scanner that is generated by switching interleaving or scanning selection pulses for each scanning line and for each field. Pixels formed at the intersections of the signal lines and the scanning lines, and a refresh signal applying unit that is commonly connected to the signal lines and applies a refresh signal to the pixels based on a selection pulse.

Further, in the driving method of the liquid crystal display device of the present invention, the signal applied to the pixel is switched according to the interlaced selection pulse and the scanning selection pulse generated by the V scanner. That is, the refresh signal is applied during the interlaced selection pulse, and the normal video signal is applied during the scanning selection pulse. Further, the interlaced selection pulse and the scanning selection pulse are switched for each scanning line, and the relationship is reversed for each field, thereby solving the above-mentioned problem.

[0017]

In the liquid crystal display device of the present invention, a V scanner generates an interlaced selection pulse or a scanning selection pulse, and when the interlaced selection pulse is generated, a refresh signal is applied, and the scanning selection pulse is selected. If it occurs, the video signal is applied. Therefore, it is possible to improve the image quality without refreshing the video signal written in the previous field and leaving it as an afterimage.

Further, in the driving method of the liquid crystal display device of the present invention, a normal interlace signal is applied when the V scanner issues a scanning selection pulse, and when the V scanner issues an interlaced selection pulse. A refresh signal is applied to the pixel to refresh the video signal written in the previous field. Therefore, the video signal written in the previous field does not remain as an afterimage, and the interlaced signal can be displayed on the liquid crystal display device with a natural image quality like a CRT.

[0019]

Embodiments of the liquid crystal display device and the driving method thereof according to the present invention will be described below with reference to FIGS. The same parts as those of the conventional liquid crystal display device are designated by the same reference numerals, and the description of their structures and operations will be omitted.

First, the structure of the liquid crystal display device of the present invention will be described with reference to FIGS. In FIG. 1, reference numeral 1
00 indicates the liquid crystal display device of the present invention. The liquid crystal display device 100 of the present invention includes an input terminal 2 to which an interlaced signal or the like is input, a decoder 3 for converting the input signal into separate signals of R, G, and B, and a video signal 5 common to conventional liquid crystal display devices. In addition to the common voltage 6, a signal driver 24 for generating a refresh signal 31, which is a feature of the present invention, HST, HCK, VS necessary for controlling a liquid crystal panel described later.
VCK1 and VCK2 newly generated from T and VCK,
A control signal 27 including ENB (enable), a refresh control pulse RF related to the present invention, a TG 28 for outputting a frame pulse FRP to the signal driver 24, and a color or monochrome liquid crystal panel for displaying an image. It is roughly composed of 20.

In the detailed structure of the liquid crystal panel 20, an H scanner 21 for sequentially selecting signal lines by a horizontal shift register and a V scanner 22 for selecting each line by a vertical shift register are interpolated. A signal line 24 is connected to the scanner 21 via a switching device 23.
The V scanner 22 has lines 25 arranged in a matrix. Further, each signal line 24 is connected to a refresh signal applying means 30 which is a feature of the present invention. Furthermore, the signal line 24 and the line 25
A TFT 26 is connected to the intersection of the above, and a COM electrode 27 is connected to the TFT 26 via a storage capacitor Cs and a liquid crystal cell LC.

The operation of the liquid crystal display device of the present invention having such a configuration will be described. The signal input to the input terminal 2 in FIG. 1 is input to the decoder 3. The decoder 3 converts a composite video signal into an R, G, B separate signal suitable for driving the liquid crystal panel 20 and adds an adjusting circuit (not shown) for color, picture, hue, etc. to the next stage. To the signal driver 24. The signal driver 24 converts the video signals 5 such as R, G, and B into alternating currents and outputs them, and also outputs the refresh signals 31. Specifically, as shown in the drawing, the refresh signal 31 is, for example, an AC signal having a "white level" of 2V and a "black level" of 4.5V centered on a center voltage of 6V (however, no Mari White). Further, the common voltage 6 is generated and output for the COM electrode 27 in the liquid crystal panel 20.

In the TG 28, various control signals 27 used for controlling the liquid crystal panel 20 are supplied to a VCO (not shown) or H.
It is generated from the sync signals of -Syncn and V-Sync and output to the liquid crystal panel 20 in the next stage. These control signals 27 are specifically HST, HCK, VST, (VCK1, VCK2), E
NB and refresh control pulse RF. To explain these operations, HST is a start pulse for the shift register of the H scanner 21, HCK is a clock pulse for the shift register of the H scanner 21, and VST is a shift pulse for the V scanner 22. These are start pulses, and VCK1 and VCK2 are clock pulses for the V scanner 22 described later. Also, EN
B is connected to the V scanner 22 so that a predetermined line of the V scanner 22 can be selected. The refresh control pulse RF is a control pulse for controlling the gate of the refresh signal applying means 30 in the liquid crystal panel 20 and applying the refresh signal 31 to each signal line 24, which will be described in detail later.

The liquid crystal panel 20 includes the video signals 5 such as R, G, and B, the refresh signal 31, and the refresh signal 31 from the various circuits described above.
The common voltage 6 and various control signals 27 are received and supplied to the H scanner 21, the V scanner 22, and the refresh signal applying means 30. In the TFT 26, in response to the selection pulse input supplied from the line 25 connected to the V scanner 22, the video signal 5 is taken in via the signal line 24 via the switching device connected to the H scanner 21. The captured video signal 5 is supplied to the storage capacitor CS and the liquid crystal cell LC. Refresh signal applying means 3
At 0, after the video signal is written by the H scanner 21 in response to the selection pulse of the V scanner 22,
A refresh signal 31 as shown in the figure generated by the signal driver 24 is applied to each pixel through the signal line 24 under the control of the refresh control pulse RF.

The structure and operation of the V scanner of the liquid crystal display device of the present invention will be described with reference to FIG. The V-scanner of the present invention shown as an example comprises a D-type flip-flop 32 using a clocked inverter (inverting amplifier) as shown in FIG. 2, and the D-type flip-flop 32 is a direct current 15.5V or the like. It is connected to a certain power supply VCC and a ground terminal GND. In addition, a vertical start pulse VST as an input signal and VCK which is a vertical control clock
Or, its inverted pulse, / VCK, is input (here, "/" indicates a negative logic symbol). The D-type flip-flop 32 outputs an output signal A which is a selection pulse for each line.
It outputs 1, A2 and A3. Further, the outputs of the two stages of the D flip-flop 32 are inputted to the AND circuit 33.
The AND circuit 33 ANDs the outputs of two stages of the adjacent D flip-flops 32 to obtain the TG shown in FIG.
Under the control of ENB generated by 29, selection pulses B1 and B of new lines for driving the liquid crystal display device of the present invention.
Output from the V scanner 22 as 2, B3 and B4. Hereinafter, specific examples of these timings will be described.

Next, the principle of the liquid crystal display device and the driving method thereof according to the present invention will be described with reference to FIGS.

The video signal in FIG. 3 (a) is a signal input in response to the selection pulse of each line every so-called 1 horizontal period (1 line), and the horizontal blanking period 34
And a video period 35. The liquid crystal display device of the present invention starts operation with the vertical start pulse VST as a start reference, and the vertical timing pulse VCK1 is 1
One pulse is output every horizontal blanking period 34 of the line. Then, various pulses necessary for the operation of the present invention in the V scanner 22 of the liquid crystal display device 100 of the present invention described above are generated. That is, the period from the rise of VCK1 to the rise is "high level"
A1, A3, and A5, and similarly A2 and A4, which set the falling period of VCK1 to "high level", are generated.

ENB (enable) is set to "high level" indicating non-operation, and the interlace line 36
A narrow pulse (gate pulse) B1 for scanning and a wide pulse B2 for scanning line 37 are alternately generated and output. To explain an example of the operation, for example, B3
When paying attention to, this B3 is the AND of A2 and A3 described above.
It can be seen that it is generated from. Similarly, B1 to B6 are generated from A1 to A5. However, the narrow pulse is assumed to be "high level" within the horizontal blanking period. Then, during the scanning line 37 period of B2, B4, and B6, it is output as it is as a selection pulse of the scanning line, and in response to the selection pulse of this scanning line, the video signal is sequentially fetched from the H scanner and each pixel is passed through each signal line. To display an image on each pixel.

On the other hand, in the interlaced line 36 period of B1, B3, and B5, after the writing of the video signal by the H scanner is completed, the refresh control pulse RF generated by the TG 29 of FIG. 1 is applied as shown in FIG. A predetermined refresh signal 31 is applied to 36 via the refresh signal applying means 30. As a result, all the signal lines after the writing of the video signal refresh the video signal of the scanning line 37 and also refresh the video signal of the previous field on the interlaced line 36 (facilitating the writing of the signal on the next line. Get the precharge effect). In this way, by deleting the image written in the previous field, it is possible to eliminate the afterimage feeling during interlace driving.

Similarly, in the even field of FIG. 3B, the operation is started with the vertical start pulse VST as a start reference, and the vertical timing pulse VCK2 has a phase opposite to that of VCK1 of the odd field of FIG. 3A. Output as a pulse. The vertical selection pulses A1, A3, and A5 are output with the rising period of the VCK2 set to "high level", and A2 and A4 are output to the V level.
The falling period of CK2 is output as "high level".

Further, by inputting the pulses A1, A2, A3, A4, and A5 to the V scanner of the above-mentioned liquid crystal display device of the present invention and performing a predetermined process, the width showing the interlaced line 36 as shown in the figure. Narrow pulses B2, B4, B6 are output, and wide pulses B1, B indicating the scan line 37 are output.
3 and B5 are generated and output. However, the relationship between the wide pulse and the narrow pulse indicating the scanning line 37 and the interlaced line 36 is opposite to that of the odd field in FIG. Thereafter, the same operation is performed to erase the image written in the previous field, so that the afterimage feeling at the time of interlace driving can be eliminated.

Next, a display example in the full line liquid crystal display device and the display method thereof according to the present invention will be described with reference to FIG.

Symbols + and-in FIG. 4 indicate the polarities of the video signals of the respective lines (n) in the respective fields (N). No mark indicates a scanning line, and a mark indicates an interlaced line. In the figure, it is assumed that writing is started from the N field, and in the N field, a video signal in the + direction is applied to the n line and − to the n + 2 line.
Directional signals are applied. Moving to the N + 1 field, the above-mentioned n and n + 2 fields become interlaced lines, and while being refreshed by the refresh signal, n + 1,
Video signals in the + and − directions in phase with the previous line are newly applied to the n + 3 line. In the N + 2 field, n + 1 and n written in the above N + 1 field
The +3 line becomes an interlaced line and is refreshed with a refresh signal, while the signals in the − direction and the + direction in phase with the previous line are newly applied to n and n + 2, respectively. In the N + 3 field, the n and n + 2 lines written in the N + 2 field described above become interlaced lines, and while being refreshed by the refresh signal, n
Signals of − direction and + direction in phase with the previous line are newly applied to +1 and n + 3, respectively. Thereafter, in the same manner, the liquid crystal display device of the present invention is driven by applying the image signal in the + direction → refresh → the image signal in the − direction.

To explain the driving method of the liquid crystal display device of the present invention in more detail, when the liquid crystal display device is driven by the interlace system, each pixel potential is driven at 15 Hz due to the request of AC driving to the liquid crystal panel. That is, this is perceived by the viewer as flickers at 15 Hz, which causes image quality deterioration. In order to reduce the 15 Hz component, adjacent lines are combined as shown in the figure, and four lines are regarded as one liquid crystal cell. Therefore, the frequency viewed by the viewer is 15 Hz × 4 times = 60.
It becomes possible to have Hz as the main component. 15Hz or 30
The frequency component of Hz can be reduced. That is, in the vertical direction of FIG. 4, the combinations of polarities of the video signals shown as an example in all fields are the same, and four lines can be regarded as one liquid crystal cell, and 15 Hz and 30 Hz components can be reduced.

Here, in the present embodiment, the polarity of the video signal of the interlaced line is matched with the polarity of the next line (focusing on the N + 2 field, the polarity of the n + 1 interlaced line is matched with the next line n + 2). With respect to the reduction of, the same effect can be obtained even when it is combined with the polarity of the previous line. However, by matching the polarity with the next line, the same polarity as the next line can be applied in advance during the interlaced line, and the potential difference when writing the next signal can be reduced, and the video signal accompanying the application of the video signal can be reduced. Can reduce the noise to (pre-charge effect).

The operation of the liquid crystal display device of the present invention applied to an IDTV will be described with reference to FIG. Note that FIG. 5 shows an odd field (processing example of a still image), and illustration of the even field and description of its operation are omitted.

IDTV (Improved Definition Televisio
n) is a high image quality display system in which the image quality deterioration factor due to the current broadcasting system is improved on the receiver side.Specifically, the motion of the image is detected by a digital circuit etc. This is a display system for achieving high image quality by performing interpolation, and in the case of a moving image, line interpolation.

The video signal shown in FIG. 5 is a signal input for each line and is composed of a horizontal blanking period 34 and a video period 35. The liquid crystal display device of the present invention starts its operation with the vertical start pulse VST as a reference, and the vertical timing pulse VCK1 outputs one pulse for each horizontal blanking period 34 of one line. . Then, vertical selection pulses A1, A3, and A5 are output with the rising period of the VCK1 as "high level", and similarly A2, A4.
Is output with the falling period of VCK1 as "high level". These are the pulses necessary for the operation of the V scanner of the liquid crystal display device of the present invention.

Furthermore, by selectively setting the ENB of the V scanner shown in FIG. 2 to the "low level" operation state,
B1, B3, B5 which are the interlaced lines 36 shown in FIG.
Stops output of refresh pulse of. That is, by stopping the pulse of the interlaced line 36, the video signal after writing is held, and the image quality of a still image is improved without using a means such as a field memory.
That is, when the liquid crystal display device of the prior art is driven by the interlace method, a high image quality can be obtained for a still image as described above. Therefore, by performing the motion detection by the motion detecting means, the liquid crystal display device of the present invention described above is applied to a moving image, and the liquid crystal display device of the present invention is applied to an IDTV (FIG. 5) when a still image is displayed. An IDTV system with a display device can be realized.
This makes it possible to omit the conventionally required field memory for interpolation, and realize an IDTV system with a low-cost liquid crystal display device.

The present invention is not limited to the above embodiment, and various embodiments can be adopted. For example, the case where the input video signal is analog has been described in the above embodiment, but the same is applicable to the case where the video signal is digital. In addition, although the case where the full-line liquid crystal display device is driven by the interlace system is described in the present embodiment, it is also possible to display by converting to the non-interlace system.
It is also possible to temporarily switch between the interlace system and the non-interlace system for display. Further, it is needless to say that the present invention is not particularly limited to the liquid crystal mode and system and can be applied to the ferroelectric liquid crystal and other display devices.

[0041]

As described above, according to the liquid crystal display device and the driving method thereof of the present invention, when the full line liquid crystal display device is driven by the interlace method, the interlaced lines written in the previous field are refreshed. Since a signal is applied and refreshed, an afterimage that occurs when a conventional full-line liquid crystal display device is driven by an interlace system can be eliminated, and an interlaced signal can be displayed with a natural image quality. It will be possible. Further, it is possible to reduce pixel noise associated with charging / discharging of a video signal and visual flicker.

Further, in the liquid crystal display device and the driving method thereof according to the present invention, since it is not necessary to use the field memory for interpolation or other means, it is possible to realize a low cost liquid crystal display device without requiring additional hardware. . Furthermore,
According to the liquid crystal display device and the driving method thereof of the present invention, by switching between a moving image and a still image by a motion detection circuit or the like, an IDTV by a low-cost liquid crystal display device which does not require a field memory for interpolation which was originally necessary. The system can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a full-line liquid crystal display device of the present invention.

FIG. 2 is a circuit diagram showing an example of a second V scanner of the present invention.

FIG. 3 is a timing chart showing the operation of the liquid crystal display device of the present invention, (a) showing an odd field and (b) showing an even field.

FIG. 4 is an explanatory diagram showing an example of a writing operation for each field of the liquid crystal display device of the present invention.

FIG. 5 shows a liquid crystal display device and a driving method thereof according to the present invention.
It is a timing chart applied to DTV, and shows an odd field (processing example of a still image).

FIG. 6 is a block diagram showing a conventional liquid crystal display device and a driving method thereof.

[Explanation of symbols]

 1 Conventional liquid crystal display device 2 Input terminal 3 Decoder 4, 24 Signal driver 5 Video signal 6 Common voltage 7, 27 Control signal 8, 28 Timing generator TG 10, 20 Liquid crystal panel 11, 21 H scanner 12, 22 V scanner 13, 23 Switching device 14, 24 Signal line 15, 25 Scan line (line) 16, 26 TFT 17, 27 COM electrode 30 Refresh signal applying means 31 Refresh signal 32 D flip-flop 33 AND circuit 34 Horizontal blanking period 35 Video period 36 Interlaced line 37 Scanning line 100 Liquid crystal display device of the present invention VCC power supply GND Ground terminal

Claims (9)

[Claims] 1. A liquid crystal display device for driving a full-line liquid crystal display device by an interlace method, comprising: a signal driver for generating a refresh signal; a timing generator for generating a control signal, an enable signal and a refresh control pulse; and a signal. An H scanner to which a line is connected; a V scanner to which a scanning line is connected and which receives the control signal and the enable signal to generate an interlace and scanning selection pulse; and a V scanner formed at the intersection of the signal line and the scanning line. And a refresh signal applying unit that is commonly connected to the signal line and applies the refresh signal to the pixel in response to the selection pulse generated by the V scanner. Liquid crystal display device. 2. The liquid crystal display device according to claim 1, wherein the interlace and scan selection pulses are switched for each scanning line. 3. The liquid crystal display device according to claim 1, wherein the relationship between the interlaced and scanning selection pulses is switched for each field. 4. The liquid crystal display device according to claim 1, wherein the refresh signal has a predetermined AC voltage level between a black level and a white level of the video signal. 5. A driving method of a liquid crystal display device for driving a full line liquid crystal display device by an interlace method, comprising a signal driver for generating a refresh signal, and a timing generator for generating a control signal, an enable signal and a refresh control pulse. An H scanner to which a signal line is connected; a V scanner to which a scanning line is connected and which receives the control signal and the enable signal to generate an interlace and scanning selection pulse; and a V scanner of the signal line and the scanning line. A pixel formed at the intersection, and a refresh signal applying unit that is commonly connected to the signal line and applies the refresh signal to the pixel in response to the selection pulse generated by the V scanner, In response to the selection pulse generated by the V scanner, when the interlaced selection pulse, Method for driving a liquid crystal display device applies a shoe signal to the pixel, characterized by applying a normal video signal when the scanning selection pulse. 6. The method of driving a liquid crystal display device according to claim 5, wherein the timing of applying the refresh signal is a horizontal blanking period. 7. The method for driving a liquid crystal display device according to claim 5, wherein the interlace and scan selection pulses are switched for each scanning line. 8. The method of driving a liquid crystal display device according to claim 5, wherein the relationship between the interlaced and scanning selection pulses is switched for each field. 9. The method of driving a liquid crystal display device according to claim 5, wherein the refresh signal has a predetermined AC voltage level between a black level and a white level of the video signal.