JP2006301213A - Liquid crystal display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of persistence and flickering by inserting a black line having optimum width. <P>SOLUTION: When the number of black lines set on the basis of the size information of a liquid crystal display panel part, the number-of-pixels information of liquid crystal pixels, the brightness information of the liquid crystal display panel part, and the display changing speed information of the liquid crystal pixels is one for instance, the one black line is successively scanning in the downward direction in an one-frame period and the scanning of the whole pixels of the vertical direction is completed in the one-frame period. In the processing, the whole image on a screen is not replaced in each frame, but each one-pixel width in the horizontal direction is successively replaced. Thereby persistence on the liquid crystal display panel part are reduced in the processing and a sense of flickering can be reduced, so that a user does not visually feel persistence and flickering. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a liquid crystal display device used as a display device such as a television receiver or a personal computer.

In recent years, light-weight, thin, and low power consumption liquid crystal display devices (LCDs) have been used in display devices such as television receivers and personal computers in place of conventional cathode ray tubes (CRTs).

The liquid crystal display device applies an electric field to a liquid crystal layer having an anisotropic dielectric constant injected between two substrates, and adjusts the intensity of the electric field to adjust the amount of light transmitted through the substrate. Thus, a desired image is obtained. Such a liquid crystal display device is a typical portable flat panel display device, and among them, a thin film transistor (TF)
A device using T) as a switching element is widespread.

By the way, the liquid crystal display device used for a personal computer has conventionally dealt mainly with a still image. However, in recent years, the liquid crystal display device used for a television receiver has also dealt with a moving image. Such a liquid crystal display device is required to have a high response speed for moving images.

Here, in order to realize a liquid crystal display device having a high response speed to a moving image, the following problems must be solved. That is, in general, in a liquid crystal display panel of a liquid crystal display device,
The time to change from one halftone to another is long, and the halftone is a frame period (for example,
In the case of 60 Hz progressive scan, it is impossible to display within 16.7 msec), and the problem that an afterimage occurs must be solved. Further, in the liquid crystal display device, the charge stored by applying the electric field to the liquid crystal is held at a relatively high rate until the next electric field is applied, so that the liquid crystal pixel is based on the video signal of the next frame. The problem of so-called blurring of the image, in which the viewer continues to emit light until it is rewritten by applying an electric field and displays a moving image, the contour of the moving part is perceived by the viewer, must be solved.

Therefore, the video signal and the black line signal are repeated within one frame period of the input video signal,
By writing to the liquid crystal display panel, the pixel emission time (image display period) is shortened from the scanning of a certain video signal frame to the scanning of the next frame, thereby realizing a pseudo impulse display system. A so-called black display signal writing type liquid crystal display device has been proposed (
For example, see Patent Documents 1, 2, 3, 4, and 5).

That is, in such a conventional liquid crystal display device, in addition to selecting each scanning line for image display in the electrode driving unit, each scanning line is selected again for black display, and the input video is accordingly displayed. A series of operations of supplying the signal and the black line signal to the data line is performed in one frame cycle, thereby generating a black display period for displaying the black line signal between a certain frame image display and the next frame image display. Is.
Japanese Patent Laid-Open No. 9-127717 JP-A-11-109921 Japanese Patent Laid-Open No. 2004-253827 Japanese Patent Laid-Open No. 9-18814 JP 2002-123223 A JP 2001-42282 A JP 2004-301984 A JP 2003-315765 A

However, in the conventional liquid crystal display device as described above, if the black display period is increased, the video display period is shortened and the video is darkened. Therefore, the light emission luminance of the backlight source disposed on the back surface of the liquid crystal display panel Can increase the display brightness of the video,
Increasing the brightness of the backlight source shortens the lifetime of the backlight source,
There arises a problem that power consumption increases.

In the prior art of Patent Document 6, the data screen and the black screen are alternately repeated for each frame. However, since the black display period increases, the above-described problem cannot be solved. In the prior art of Patent Document 7, the (N−1) frame period in the N frame period is R
The GB data signal is supplied to the data driver as a black display data signal for one frame period, and N
Although the black screen is displayed once in the frame, since the black screen has a shorter period than the data screen, afterimages tend to be hardly suppressed. In the prior art of Patent Document 8, another image is inserted between the video image and the video image. However, another image must be generated, and an afterimage with respect to the other image is generated. I can't say there is.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a liquid crystal display device capable of preventing afterimages and flickering by inserting a black line having an optimum width. To do.

In order to achieve the above object, the invention of claim 1 is a liquid crystal display panel section in which a plurality of liquid crystal display cells each having a display element corresponding to a liquid crystal pixel and a switching element for driving the display element are arranged in a matrix. In the same liquid crystal display cell group in the same row direction of the liquid crystal display panel unit, the row direction control line group connected to the control terminal of each switching element and the control line of the control line group are selectively scanned to perform the corresponding switching. A control signal supply section for supplying a control signal to the control terminal of the element, and a column-direction video signal line connected to the video signal terminal of each switching element in the same column-direction liquid crystal display cell group of the liquid crystal display panel section And a video signal supply unit that selectively scans the video signal lines of the video signal line group and supplies the video signals to the video signal terminals of the switching elements. In the crystal display device, each black line signal applying switching element that is provided in each liquid crystal display cell of the liquid crystal display panel unit and applies a black line signal to each display element, and a black control terminal of each black line signal applying switching element The black control line group in the row direction respectively connected to the black control line, and the black control line of the black control line group are selectively scanned to supply a black line control signal to the black control terminal of the switching element for applying the black line signal. A black line signal line group in the column direction connected to the control signal supply unit, a black line signal terminal of each black line signal application switching element in the same column direction, and a black line signal line of this black line signal line group A black line signal supply unit that selectively scans and supplies a black line signal to the black line signal terminal of the switching element for applying the black line signal, the control signal supply unit, the video signal supply unit, and the black line control signal supply And the black line signal supply unit A control unit that controls, a flash memory that stores size information of the liquid crystal display panel unit, pixel number information of the liquid crystal pixels, brightness information of the liquid crystal display panel unit, and display change rate information of the liquid crystal pixels The control unit is based on the size information of the liquid crystal display panel unit, the pixel number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel unit, and the display change speed information of the liquid crystal pixels stored in the flash memory. The black line control signal supply unit and the black line control signal supply unit and the number of black lines that are sequentially scanned downward in a frame period are visually set optimally and the set number of black lines are inserted into the liquid crystal display panel. Provided is a liquid crystal display device that controls the black line signal supply unit.

In this configuration, a control signal supply unit that selectively scans the control lines of the control line group and supplies a control signal to the control terminal of the corresponding switching element, and a video signal line of the video signal line group that selectively scans and controls the corresponding switching element. By controlling the video signal supply unit that supplies the video signal to the video signal terminal, a target video is displayed on the liquid crystal display panel unit.

In addition, a black line control signal supply unit that selectively scans the black control line of the black control line group and supplies a black line control signal to the black control terminal of the switching element for applying the black line signal, and a black line of the black line signal line group A black line signal supply unit that selectively scans the line signal line and supplies the black line signal to the black line signal terminal of the switching element for applying the black line signal is controlled to display the set number of black lines on the liquid crystal display panel. Inserted into the section.

Assume that the number of black lines set based on the size information of the liquid crystal display panel unit, the pixel number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel unit, and the display change speed information of the liquid crystal pixels is, for example, one. The single black line is sequentially scanned downward in one frame period, and the entire scanning is completed for the number of pixels in the vertical direction in one frame period. By such processing, the image is not completely replaced for each frame on the screen, but the horizontal one pixel width is sequentially replaced.

According to this configuration, the number of black lines is visually optimal based on the size information of the liquid crystal display panel section, the pixel number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel section, and the display change speed information of the liquid crystal pixels. Since the set number of black lines are sequentially scanned downward in one frame period, the liquid crystal display panel portion reduces the afterimage and reduces flickering in terms of processing. As a result, the afterimage and flicker are not felt visually. Further, since an image with appropriate brightness can be obtained without increasing the light emission luminance of the backlight light source, power consumption is reduced and the lifetime of the backlight light source can be extended.

According to a second aspect of the present invention, there is provided a liquid crystal display device including a liquid crystal display panel unit in which a plurality of liquid crystal display cells each having a display element corresponding to a liquid crystal pixel are arranged in a matrix, and the size information of the liquid crystal display panel unit and the liquid crystal display panel unit Based on the pixel number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel unit, and the display change speed information of the liquid crystal pixels, the number of black lines scanned sequentially downward in one frame period is visually optimized. There is provided a liquid crystal display device comprising a control unit configured to perform control so that the set number of black lines are inserted into the liquid crystal display panel.

In this configuration, the number of black lines set based on the size information of the liquid crystal display panel unit, the pixel number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel unit, and the display change rate information of the liquid crystal pixels is, for example, two. If so, the two black lines are sequentially scanned downward in one frame period, and the entire scanning is completed for the number of pixels in the vertical direction in one frame period. By such a process, the image is not completely replaced for each frame on the screen, but the two pixel widths in the horizontal direction are sequentially replaced.

According to this configuration, the number of black lines is visually optimal based on the size information of the liquid crystal display panel section, the pixel number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel section, and the display change speed information of the liquid crystal pixels. Since the set number of black lines are sequentially scanned downward in one frame period, the liquid crystal display panel portion reduces the afterimage and reduces flickering in terms of processing. As a result, the afterimage and flicker are not felt visually. Further, since an image with appropriate brightness can be obtained without increasing the light emission luminance of the backlight light source, power consumption is reduced and the lifetime of the backlight light source can be extended.

The invention of claim 3 is a liquid crystal display panel portion in which a plurality of liquid crystal display cells having a display element corresponding to a liquid crystal pixel and a switching element for driving the display element are arranged in a matrix,
The row-directional control line group connected to the control terminal of each switching element in the liquid crystal display cell group in the same row direction of the liquid crystal display panel unit, and the corresponding switching element by selectively scanning the control line of this control line group A control signal supply section for supplying a control signal to the control terminals of the liquid crystal display panel section, and a video signal line group in the column direction connected to the video signal terminals of the switching elements in the liquid crystal display cell group in the same column direction of the liquid crystal display panel section. And a video signal supply unit that selectively scans the video signal lines of the video signal line group and supplies a video signal to the video signal terminal of the corresponding switching element, the size information of the liquid crystal display panel unit On the basis of the pixel number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel unit, and the display change speed information of the liquid crystal pixels. A liquid crystal display comprising: a control unit configured to visually set an optimal number of black lines to be scanned and to control the set number of black lines to be inserted into the liquid crystal display panel Providing equipment.

In this configuration, a control signal supply unit that selectively scans the control lines of the control line group and supplies a control signal to the control terminal of the corresponding switching element, and a video signal line of the video signal line group that selectively scans and controls the corresponding switching element. By controlling the video signal supply unit that supplies the video signal to the video signal terminal, a target video is displayed on the liquid crystal display panel unit.

Also, a black line that sequentially scans downward in one frame period based on the size information of the liquid crystal display panel, the number of pixels of the liquid crystal pixels, the brightness information of the liquid crystal display panel, and the display change rate information of the liquid crystal pixels. Are visually optimally set, and the set number of black lines are inserted into the liquid crystal display panel.

Assume that the number of black lines set based on the size information of the liquid crystal display panel unit, the pixel number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel unit, and the display change speed information of the liquid crystal pixels is, for example, one. The single black line is sequentially scanned downward in one frame period, and the entire scanning is completed for the number of pixels in the vertical direction in one frame period. By such processing, the image is not completely replaced for each frame on the screen, but the horizontal one pixel width is sequentially replaced.

According to this configuration, the number of black lines is visually optimal based on the size information of the liquid crystal display panel section, the pixel number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel section, and the display change speed information of the liquid crystal pixels. Since the set number of black lines are sequentially scanned downward in one frame period, the liquid crystal display panel portion reduces the afterimage and reduces flickering in terms of processing. As a result, the afterimage and flicker are not felt visually. Further, since an image with appropriate brightness can be obtained without increasing the light emission luminance of the backlight light source, power consumption is reduced and the lifetime of the backlight light source can be extended.

According to a fourth aspect of the present invention, in the third aspect of the invention, each black line signal applying switching element that is provided in each liquid crystal display cell of the liquid crystal display panel unit and applies a black line signal to each display element, and each black line The black control line group in the row direction respectively connected to the black control terminal of the signal applying switching element and the black control line of the black control line group are selectively scanned to the black control terminal of the corresponding black line signal applying switching element. A black line control signal supply unit for supplying a black line control signal, a black line signal line group in the column direction connected to a black line signal terminal of each black line signal application switching element in the same column direction, A black line signal supply unit that selectively scans a black line signal line of the line signal line group and supplies a black line signal to the black line signal terminal of the black line signal application switching element; and size information of the liquid crystal display panel unit, Information on the number of pixels of the liquid crystal pixel and the previous A flash memory storing brightness information of the liquid crystal display panel unit and display change speed information of the liquid crystal pixels, and the control unit controls the control signal supply unit and the video signal supply unit, and Based on the size information of the liquid crystal display panel unit, the number of pixels of the liquid crystal pixels, the brightness information of the liquid crystal display panel unit, and the display change rate information of the liquid crystal pixels stored in the memory, scanning is sequentially performed downward in one frame period. The number of black lines to be visually set is optimally set, and the black line control signal supply unit and the black line signal supply unit are controlled so that the set number of black lines are inserted into the liquid crystal display panel. Therefore, the number of black lines is visually maximized based on the size information of the liquid crystal display panel, the number of pixels of the liquid crystal pixels, the brightness information of the liquid crystal display panel, and the display change speed information of the liquid crystal pixels. Can be set to a black line of the set number is possible to scan sequentially downward in one frame period.

As described above, according to the present invention, a liquid crystal display panel unit in which a plurality of liquid crystal display cells each having a display element corresponding to a liquid crystal pixel and a switching element for driving the display element are arranged in a matrix, and the liquid crystal display panel The control line group in the row direction connected to the control terminal of each switching element in the liquid crystal display cell group in the same row direction, and the control line of this control line group is selectively scanned to the control terminal of the corresponding switching element. A control signal supply unit for supplying a control signal, a video signal line group in a column direction connected to a video signal terminal of each switching element in a liquid crystal display cell group in the same column direction of the liquid crystal display panel unit, and the video A liquid crystal display device including a video signal supply unit that selectively scans video signal lines of a signal line group and supplies a video signal to a video signal terminal of a corresponding switching element. Connected to each black line signal application switching element that is provided in each liquid crystal display cell of the liquid crystal display panel section and applies a black line signal to each display element, and to each black control terminal of each black line signal application switching element. A black line control signal that supplies a black line control signal to the black control terminal of the switching element for applying the black line signal by selectively scanning the black control line group in the row direction and the black control line of the black control line group And the black line signal line group in the column direction connected to the black line signal terminal of each black line signal application switching element in the same column direction, and the black line signal lines of this black line signal line group are selectively scanned. A black line signal supply unit for supplying a black line signal to the black line signal terminal of the black line signal application switching element, the control signal supply unit, the video signal supply unit, the black line control signal supply unit, Control unit that controls the black line signal supply unit A flash memory storing size information of the liquid crystal display panel unit, pixel number information of the liquid crystal pixels, brightness information of the liquid crystal display panel unit, and display change rate information of the liquid crystal pixels, and the control unit includes: , The size of the liquid crystal display panel, the number of pixels of the liquid crystal pixels, the brightness information of the liquid crystal display panel, and the display change rate information of the liquid crystal pixels stored in the flash memory. The number of black lines scanned in the direction is set visually optimally, and the black line control signal supply unit and the black line signal supply are set so that the set number of black lines are inserted into the liquid crystal display panel. The number of black lines is visually determined based on the size information of the liquid crystal display panel, the number of pixels of the liquid crystal pixels, the brightness information of the liquid crystal display panel, and the display change speed information of the liquid crystal pixels. The set number of black lines are sequentially scanned downward in one frame period, so that the liquid crystal display panel portion has reduced afterimage and less flickering in terms of processing. As a result, the afterimage and flicker are not felt visually. Further, since an image with appropriate brightness can be obtained without increasing the light emission luminance of the backlight light source, power consumption is reduced and the lifetime of the backlight light source can be extended.

According to the present invention, in a liquid crystal display device including a liquid crystal display panel unit in which a plurality of liquid crystal display cells each having a display element corresponding to a liquid crystal pixel are arranged in a matrix, the size information of the liquid crystal display panel unit and Based on the pixel number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel section, and the display change speed information of the liquid crystal pixels, the number of black lines that are sequentially scanned downward in one frame period is visually optimized. And a control unit that performs control so that the set number of black lines are inserted into the liquid crystal display panel. Therefore, the size information of the liquid crystal display panel unit, the pixel number information of the liquid crystal pixels, and the liquid crystal display are provided. The number of black lines is visually set optimally based on the brightness information of the panel section and the display change speed information of the liquid crystal pixels, and the set number of black lines are sequentially scanned downward in one frame period. Thus, the liquid crystal display panel unit, the processing manner to become what flickering is small with afterimage is reduced, as a result, becomes does not feel afterimage and flickering visually. Further, since an image with appropriate brightness can be obtained without increasing the light emission luminance of the backlight light source, power consumption is reduced and the lifetime of the backlight light source can be extended.

In addition, according to the present invention, a liquid crystal display panel unit in which a plurality of liquid crystal display cells each having a display element corresponding to a liquid crystal pixel and a switching element for driving the display element are arranged in a matrix, and the liquid crystal display panel unit A row-directional control line group connected to the control terminal of each switching element in the same liquid crystal display cell group in the same row direction, and a control signal to the control terminal of the corresponding switching element by selectively scanning the control line of this control line group A control signal supply unit for supplying the video signal, a video signal line group in the column direction connected to the video signal terminals of the switching elements in the liquid crystal display cell group in the same column direction of the liquid crystal display panel unit, and the video signal line In a liquid crystal display device including a video signal supply unit that selectively scans a group of video signal lines and supplies a video signal to a video signal terminal of a corresponding switching element, Based on the size information of the liquid crystal display panel section, the pixel number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel section, and the display change speed information of the liquid crystal pixels, scanning is sequentially performed downward in one frame period. Since the number of black lines is set optimally visually, and a control unit is provided to control so that the set number of black lines are inserted into the liquid crystal display panel, the size information of the liquid crystal display panel unit and Based on the pixel number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel section, and the display change speed information of the liquid crystal pixels, the number of black lines is visually set optimally. Scanned sequentially down the frame period,
In the liquid crystal display panel, afterimages are reduced in processing and the feeling of flickering is reduced. As a result, the afterimages and flickering are not visually felt. Further, since an image with appropriate brightness can be obtained without increasing the light emission luminance of the backlight light source, power consumption is reduced and the lifetime of the backlight light source can be extended.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of a liquid crystal display device according to an embodiment of the present invention.

In FIG. 1, the liquid crystal display device includes a display element 11 corresponding to a liquid crystal pixel and the display element 1.
A liquid crystal display panel unit 10 in which a plurality of liquid crystal display cells 1 having a thin film transistor (hereinafter referred to as TFT) 12 as a switching element for driving 1 are arranged in a matrix, and the liquid crystal display panel unit 10 in the same row direction In the liquid crystal display cell group 1, the control lines 2 in the row direction connected to the gates as the control terminals of the respective TFTs 12 in the liquid crystal display cell group 1 and the control lines 2 of the control line 2 groups are selectively scanned, and control signals are sent to the gates of the corresponding TFTs 12. A control signal supply unit 4 for supplying;
In the same liquid crystal display cell group 1 in the liquid crystal display panel unit 10, the video signal lines 3 in the column direction respectively connected to the sources as the video signal terminals of the respective TFTs 12 in the liquid crystal display cell group 1, and the video signals of the video signal lines 3 group A video signal supply unit 5 that selectively scans the line 3 and supplies a video signal to the source of the corresponding TFT 12 is provided. The negative electrode 13 of the display element 11 is a common electrode for all the liquid crystal display cells 1.

Further, this liquid crystal display device is provided with each black line signal applying TFT 14 provided in each liquid crystal display cell 1 for applying a black line signal to each display element 11 and a black line control terminal of each black line signal applying TFT 14 as a gate. The black line control lines 9 in the row direction respectively connected to the black line control lines 9 and the black line control lines 9 of the black line control lines 9 group are selectively scanned to supply the black line control signal to the gate of the corresponding black line signal application TFT 14. The black line control signal supply unit 6 to be connected, the black line signal lines 8 in the column direction connected to the sources of the black line signal application TFTs 14 in the same column direction, and the black lines of the black line signal lines 8 A black line signal supply unit 7 that selectively scans the signal line 8 and supplies a black line signal to the source of the corresponding black line signal application TFT 14 is provided.

Further, the liquid crystal display device includes a control unit 15 that controls the control signal supply unit 4, the video signal supply unit 5, the black line control signal supply unit 6, and the black line signal supply unit 7, and the size of the liquid crystal display panel unit 10. A flash memory 16 storing information, pixel number information of the liquid crystal pixels (number information of the display elements 11), brightness information of the liquid crystal display panel unit 10, and display change speed information of the liquid crystal pixels (display elements 11). Yes. In particular, the control unit 15 is based on the size information of the liquid crystal display panel unit 10, the pixel number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel unit 10, and the display change rate information of the liquid crystal pixels stored in the flash memory 16. Thus, the number of black lines that are sequentially scanned downward in one frame period is visually set optimally, and the black line control signal is supplied so that the set number of black lines is inserted into the liquid crystal display panel 10. The unit 6 and the black line signal supply unit 7 are controlled.

In order to set the number of black lines to the visually best state, in the liquid crystal display device to be used, the size of the liquid crystal display panel, the number of liquid crystal pixels, the brightness of the liquid crystal display panel (the backlight light source) (Brightness when brightness is standard) and the display change speed of the liquid crystal pixels are determined in advance at the design stage, so the number of black lines is increased sequentially from one to visually reduce afterimages and flicker. Set the number of black lines when you feel the least, and the number of black lines set is 1
The control unit 15 controls the black line control signal supply unit 6 and the black line signal supply unit 7 so as to sequentially scan downward in the frame period.

For example, if the optimum number of black lines is one, the liquid crystal display cells 1 in the liquid crystal display panel unit 10 may be sequentially driven downward within one frame period for each row. If the optimum number of black lines is two, the liquid crystal display cells 1 in the liquid crystal display panel unit 10 may be sequentially driven downward in one frame period by two rows. By such driving, the optimal number of black lines are sequentially scanned in the downward direction in one frame period, so that the afterimage and flicker are not visually felt.

FIG. 2 is a timing chart for explaining the writing and erasing timing of the liquid crystal pixels in the vertical scanning period of one frame in the present embodiment. FIG. 2A shows a vertical synchronization signal which is a reference for timing for driving the liquid crystal display cell 1 of the liquid crystal display panel unit 10.
FIG. 2B shows a display write start pulse for starting the writing of the video signal to the display element 11 of the liquid crystal display cell 1 in the liquid crystal display panel unit 10. FIG. 2 (3) shows a black writing start pulse for starting writing of a black line signal to the display element 11 of the liquid crystal display cell 1 in the liquid crystal display panel unit 10.

FIG. 3 is a diagram for explaining a state in which a black line is scanned in one frame period in the present embodiment. As shown in FIG. 3, for example, a black line with zero luminance corresponding to one pixel width is B in the horizontal direction of video A.
1, B 2, B 3,... B (n−3), B (n−2), B (n−1), and Bn are scanned in the vertical direction and the number of pixels in the vertical direction in one frame period The scanning of the entire black line is completed.

Next, the operation of the liquid crystal display device of this embodiment will be described with reference to FIGS. When power is supplied to the liquid crystal display device, light from a backlight light source (not shown) is applied to the back surface of the liquid crystal display panel 10 to display an image on the liquid crystal display panel 10. The video signal supply unit 5 receives the video signal from the signal processing circuit of the machine.
And a vertical synchronization signal (see FIG. 2 (1)) from the signal processing circuit is input,
A video writing start pulse (see FIG. 2B) synchronized with the vertical synchronizing signal is output to the control signal supply unit 4, and a black line writing start pulse (FIG. 2 (FIG. 2) is delayed by a predetermined timing from the generation of the video writing pulse. 3) is output to the black line control signal supply unit 6.

Further, the control unit 15 reads the size information of the liquid crystal display panel unit 10, the pixel number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel unit 10, and the display change rate information of the liquid crystal pixels from the flash memory 16. Based on the information, the number of black lines scanned sequentially downward in one frame period is set visually optimally, and the black lines are inserted so that the set number of black lines is inserted into the liquid crystal display panel 10. The control signal supply unit 6 and the black line signal supply unit 7 are controlled.

The video signal supply unit 5 gives a video signal to the source of the TFT 12 of the liquid crystal display panel unit 10,
Similarly, the control signal supply unit 4 gives a drive signal to the gate of the TFT 12 so that, for example, a video A as shown in FIG. 3 is displayed on the liquid crystal display panel 10 in one frame period.

Specifically, when a control line (control line of two control lines) arbitrarily selected by the control signal supply unit 4 is driven within a certain vertical scanning period of one frame, the selected control line and video signal line 3 are selected. A voltage corresponding to the voltage of the video signal is applied from the video signal supply unit 5 to the display element (liquid crystal pixel) 11 group through the TFT 12 group connected to the group. Thus, the video signal can be written to one screen by sequentially changing the drive of the control line 2 corresponding to the video signal line 3 to which the voltage of the video signal is inputted.

At this time, the black line signal supply unit 7 gives a black line signal to the source of the TFT 14 of the liquid crystal display panel unit 10, and the black line control signal supply unit 6 similarly gives a drive signal to the gate of the TFT 14, For example, as shown in FIG. 3, black lines B1, B2, B3,... B (n−
3), B (n-2), B (n-1), and Bn are inserted in one frame period.

More specifically, when the black line control lines 9 selected in order from the top by the black line control signal supply unit 6 are driven within the same vertical scanning period of one frame, the selected black line control line 9 and the black line signal are selected. A voltage corresponding to the voltage of the black line signal is applied from the black line signal supply unit 7 to the display element 11 group through the TFT 14 group connected to the line 8 group. By repeating such an operation while changing the black line control line 9 to be driven, scanning of the entire black line is completed for the number of pixels in the vertical direction in one frame period.

In these series of operations, the control line 2 and the black line control line 9 are driven so as not to apply a voltage to the same display element 11 at the same time. By sequentially erasing the pixel width (when the number of black lines is one) at the same time, the liquid crystal display panel unit 10 reduces the afterimage in processing and reduces flickering. Visually, the afterimage and flicker are not felt.

That is, in this embodiment, since each pixel (display element 11 of each liquid crystal display cell 1) once becomes zero brightness and then replaced with the next video signal, the afterimage and flicker peculiar to the liquid crystal display device can be suppressed. In addition, the number of black lines is the optimum number based on the size information of the liquid crystal display panel unit 10, the pixel number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel unit 10, and the display change speed information of the liquid crystal pixels. Therefore, afterimages and flickering disappear visually, and a clear image is projected to the human eye. Further, since an image with appropriate brightness can be obtained without increasing the light emission luminance of the backlight light source, power consumption is reduced and the lifetime of the backlight light source can be extended.

In the above-described embodiment, the case where the number of black lines is one has been described. However, if the number of black lines that does not visually cause an afterimage and flickering is m, a bundle of m black lines is bundled. The process may be performed as follows.

It is a block diagram which shows the structure of the liquid crystal display device which concerns on one Embodiment of this invention. 4 is a timing chart for explaining the writing and erasing timings of liquid crystal pixels within a vertical scanning period of one frame in the embodiment. It is a figure for demonstrating the state by which a black line is scanned in 1 frame period in this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display cell 2 Control line 3 Video signal line 4 Control signal supply part 5 Video signal supply part 6 Black line control signal supply part 7 Black line signal supply part 8 Black line signal line 9 Black line control line 10 Liquid crystal display panel part 11 Display element (liquid crystal pixel)
12 TFT (switching element)
14 TFT (switching element for black line signal application)
15 Control unit 16 Flash memory

Claims (4)

A liquid crystal display panel section in which a plurality of liquid crystal display cells each having a display element corresponding to a liquid crystal pixel and a switching element for driving the display element are arranged in a matrix, and a liquid crystal display cell in the same row direction of the liquid crystal display panel section A control line group in the row direction respectively connected to the control terminal of each switching element in the group, and a control signal supply unit that selectively scans the control line of this control line group and supplies a control signal to the control terminal of the corresponding switching element; The video signal line group in the column direction connected to the video signal terminal of each switching element in the liquid crystal display cell group in the same column direction of the liquid crystal display panel unit, and the video signal line of this video signal line group are selectively scanned. And a video signal supply unit that supplies a video signal to the video signal terminal of the corresponding switching element. Each black line signal applying switching element that is provided in the liquid crystal display cell and applies a black line signal to each display element, and a row black control line group connected to the black control terminal of each black line signal applying switching element And a black line control signal supply unit that selectively scans the black control lines of the black control line group and supplies a black line control signal to the black control terminal of the switching element for applying the black line signal. The black line signal line group in the column direction connected to the black line signal terminal of the black line signal application switching element and the black line signal line of this black line signal line group are selectively scanned to perform the corresponding black line signal switching. A black line signal supply unit that supplies a black line signal to a black line signal terminal of the element, the control signal supply unit, the video signal supply unit, the black line control signal supply unit, and the black line signal supply unit are controlled. The control unit and the liquid crystal display panel unit. And a flash memory that stores information on the number of pixels of the liquid crystal pixels, brightness information of the liquid crystal display panel unit, and display change speed information of the liquid crystal pixels, and the control unit is stored in the flash memory. Based on the size information of the liquid crystal display panel section, the pixel number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel section, and the display change speed information of the liquid crystal pixels, the black lines sequentially scanned downward in one frame period The number of lines is set optimally visually, and the black line control signal supply unit and the black line signal supply unit are controlled so that the set number of black lines is inserted into the liquid crystal display panel. A liquid crystal display device. In a liquid crystal display device including a liquid crystal display panel unit in which a plurality of liquid crystal display cells having display elements corresponding to liquid crystal pixels are arranged in a matrix, size information of the liquid crystal display panel unit, pixel number information of the liquid crystal pixels, Based on the brightness information of the liquid crystal display panel section and the display change speed information of the liquid crystal pixels, the number of black lines that are sequentially scanned downward in one frame period is visually set optimally. A liquid crystal display device comprising a control unit that performs control so that a number of black lines are inserted into the liquid crystal display panel. A liquid crystal display panel section in which a plurality of liquid crystal display cells each having a display element corresponding to a liquid crystal pixel and a switching element for driving the display element are arranged in a matrix, and a liquid crystal display cell in the same row direction of the liquid crystal display panel section A control line group in the row direction respectively connected to the control terminal of each switching element in the group, and a control signal supply unit that selectively scans the control line of this control line group and supplies a control signal to the control terminal of the corresponding switching element; The video signal line group in the column direction connected to the video signal terminal of each switching element in the liquid crystal display cell group in the same column direction of the liquid crystal display panel unit, and the video signal line of this video signal line group are selectively scanned. And a video signal supply unit that supplies a video signal to the video signal terminal of the corresponding switching element. Based on the noise information, the number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel section, and the display change speed information of the liquid crystal pixels, the number of black lines sequentially scanned downward in one frame period is visually confirmed. A liquid crystal display device comprising a control unit configured to optimally set and to control so that the set number of black lines are inserted into the liquid crystal display panel. Each black line signal application switching element that is provided in each liquid crystal display cell of the liquid crystal display panel unit and applies a black line signal to each display element, and is connected to a black control terminal of each black line signal application switching element A black control line group in the row direction, and a black line control signal supply unit that selectively scans the black control lines of the black control line group and supplies a black line control signal to the black control terminal of the switching element for applying the black line signal; The black line signal line group in the column direction connected to the black line signal terminal of each black line signal application switching element in the same column direction and the black line signal line of the black line signal line group are selectively scanned. A black line signal supply unit that supplies a black line signal to a black line signal terminal of the switching element for applying the black line signal, size information of the liquid crystal display panel unit, pixel number information of the liquid crystal pixels, and the liquid crystal display panel unit Brightness information and the liquid crystal pixel A flash memory that stores display change speed information, and the control unit controls the control signal supply unit and the video signal supply unit, and the size information of the liquid crystal display panel unit stored in the flash memory; Based on the pixel number information of the liquid crystal pixels, the brightness information of the liquid crystal display panel section, and the display change speed information of the liquid crystal pixels, the number of black lines scanned sequentially downward in one frame period is visually set optimally. 4. The liquid crystal according to claim 3, wherein the black line control signal supply unit and the black line signal supply unit are controlled so that the set number of black lines are inserted into the liquid crystal display panel. Display device.

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