KR20070002452A - Field sequential liquid crystal display device and method for driving the same - Google Patents

Abstract

A field sequential LCD and a driving method thereof are provided to prevent color break up by increasing a turn-on time of a backlight in one frame, and adding a white sub frame to yellow and blue sub-frames in one frame. Two color filters having different mixed colors are alternately arranged. One frame is divided into a plurality of sub-frames. Two of the plurality of sub-frames emit yellow light and blue light. The remaining sub frames of the plurality of sub-frames excluding the two sub-frames emit white light. An order of emission of the yellow light and the blue light is arbitrarily changed within a sub-frame of one frame. The white light is emitted from an arbitrary sub-frame of the plurality of sub-frames of one frame.

Description

Field sequential liquid crystal display device and method for driving the same

1 is a view showing the configuration of a conventional field sequential liquid crystal display device.

FIG. 2 is a view for explaining a driving method of the field sequential liquid crystal display of FIG. 1; FIG.

3 illustrates a field sequential liquid crystal display according to an exemplary embodiment of the present invention.

4 is a view illustrating a driving method of the field sequential liquid crystal display of FIG.

5 is a view showing a color filter of the liquid crystal display of the present invention.

6 illustrates a field sequential liquid crystal display according to another exemplary embodiment of the present invention.

7A and 7B illustrate a method of driving the field sequential liquid crystal display of FIG. 6.

<Brief description of the main parts of the drawing>

105, 205, 305: Light guide plates 107, 207, 307: Backlight

108, 208, 308: Liquid crystal panel

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device and a driving method thereof capable of improving image quality.

An active matrix liquid crystal display device displays a moving image using a thin film transistor (TFT) as a switching element. Such a liquid crystal display device can be miniaturized compared to a CRT, and is widely used not only for personal computers and notebook computers, but also for office automation equipment such as copying machines, portable devices such as mobile phones and pagers.

In general, a liquid crystal display device includes a plurality of pixels arranged in a matrix form and a plurality of thin film transistors for switching data signals to be supplied to each of the pixels. The desired image is displayed. Recently, in order to improve high-speed driving and image quality, an FSC (Field Sequential Color) driving type liquid crystal display device has been actively studied.

1 is a view showing the configuration of a conventional field sequential liquid crystal display.

As shown in FIG. 1, the field sequential liquid crystal display includes a plurality of pixels arranged in a matrix, each pixel includes a liquid crystal cell, and light transmission of the pixel is performed according to a voltage applied to each pixel electrode. A liquid crystal panel 8 controlled by a liquid crystal cell, a red light source R1 and a green light source positioned at the rear surface of the liquid crystal panel 8 and emitting red, green, and blue light disposed at one end of the light guide plate 5; (G1) and a blue light source B1.

Further, the field sequential liquid crystal display device uniformly guides red, green, and blue light from the three light sources R1, G1, and B1 to the entire surface of the liquid crystal panel 8 by the light guide plate 5. It further includes a backlight 7 for illuminating the liquid crystal panel 8.

 FIG. 2 is a view for explaining a driving method of the field sequential liquid crystal display of FIG. 1.

As shown in Fig. 2, one frame period is divided into three subframes, that is, a red subframe period Rs1, a green subframe period Gs1, and a blue subframe period Bs1.

First, a red data signal Rd1 is provided by a data driver (not shown) of the liquid crystal display device during the red sub frame period Rs1 of the one subframe, and three colors of backlight are used during the red sub frame period Rs1. Of the light sources of the red light source R1 emits light, the red light corresponding to the red data signal Rd1 is incident on the liquid crystal panel 8.

Thereafter, the green data signal Gd1 is provided from the data driver during the green sub frame period Gs1, and the green light source G1 of the backlight 7 emits light during the green sub frame period Gs1 to correspond to the green data signal Gd1. Green light is incident on the liquid crystal panel 8.

Finally, the blue data signal Bd1 is provided from the data driver during the blue sub frame period Bs1, during which the blue light source B1 of the backlight 7 emits light to the blue data signal Bd1. The corresponding blue light is incident on the liquid crystal panel 8.

An image is generated at each pixel of the liquid crystal panel 8 corresponding to the red, green, and blue light sequentially incident from the red, green, and blue light sources R1, G1, and B1 into the liquid crystal panel 8.

As described above, data signals Rd1, Gd1, and Bd1 for red, green, and blue are sequentially provided to each pixel of the liquid crystal panel 8 once in each subframe within one frame period, and corresponding backlight ( The red, green, and blue light sources R1, G1, and B1 of 7) are sequentially driven, and red, green, and blue are sequentially provided to the liquid crystal panel 8. As a result, the liquid crystal panel 8 displays an image corresponding to the R, G, and B data signals provided during one frame.

In the case of the liquid crystal display device driven by the field sequential method, it is possible to realize 3 times higher resolution in the panel of the same size than the driving method of the general liquid crystal display device and to improve the light efficiency by not using the color filter. Degradation may cause a deterioration in image quality.

An object of the present invention is to provide a field sequential liquid crystal display device and a driving method thereof capable of improving image quality.

Field sequential liquid crystal display device according to an embodiment of the present invention for achieving the above object is a two color filter having a different mixed color, a yellow light source for emitting yellow, blue and white light, blue light source and white light source It includes a backlight and a liquid crystal panel for displaying an image according to the light sequentially generated from the backlight.

Field sequential liquid crystal display according to another embodiment of the present invention for achieving the above object is a backlight and the backlight having two color filters having different mixed colors, a yellow and blue light source for emitting yellow and blue light And a liquid crystal panel which displays an image according to the light sequentially generated in the.

According to an aspect of the present invention, there is provided a method of driving a field sequential liquid crystal display, alternately arranging two color filters having different mixed spectra, and converting one frame into a plurality of subframes. Separating the light, emitting yellow and blue light in two of the plurality of subframes, and emitting white light in the remaining subframes other than the two subframes of the plurality of subframes.

According to another aspect of the present invention, there is provided a method of driving a field sequential liquid crystal display, alternately arranging two color filters having different mixed spectra, and converting one frame into a plurality of subframes. Separating the light, sequentially emitting yellow and blue light in two subframes of the plurality of subframes, and simultaneously emitting the yellow and blue light in the remaining subframes other than the two subframes of the plurality of subframes. It comprises the step of.

Hereinafter, with reference to the accompanying drawings will be described an embodiment according to the present invention.

3 is a diagram illustrating a field sequential liquid crystal display according to an exemplary embodiment of the present invention.

As shown in FIG. 3, the field sequential liquid crystal display includes a plurality of pixels arranged in a matrix, each pixel includes a liquid crystal cell, and light transmission of the pixel is performed according to a voltage applied to each pixel electrode. A yellow light source Y1 and a blue light emitting yellow light that combines a liquid crystal panel 108 controlled by a liquid crystal cell and a red and green light disposed on the rear surface of the liquid crystal panel 108 and disposed at one end of the light guide plate 105. A blue light source B1 that emits light of light is provided. The field sequential liquid crystal display further includes a color filter (not shown).

Further, the field sequential liquid crystal display device uniformly guides yellow light and blue light from the two-color light sources R1 + G1 = Y1 and B1 to the entire surface of the liquid crystal panel 108 by the light guide plate 105. It further includes a backlight 107 for illuminating the liquid crystal panel 108.

4 is a diagram illustrating a method of driving the field sequential liquid crystal display of FIG. 3.

As shown in FIG. 4, the first subframe Ys1 and the second subframe in which the light source of blue B1 is turned on turn on the yellow light source Y1 in which one frame is combined with the red and green (R1 + G1) lights. Separated by (Bs1).

That is, in the driving method of the field sequential liquid crystal display according to the exemplary embodiment of the present invention, one frame is divided into two first and second subframes Ys1 and Bs1.

Each subframe is divided into a data application time AP, a liquid crystal response time WP, and a backlight emission time FP. As a result, the time FP for turning on the backlight according to each color is the time excluding the data application time AP and the liquid crystal response time WP.

As a result, the backlight of the field sequential liquid crystal display increases the luminance rather than being constituted by one frame. In the driving method of the field sequential liquid crystal display, the data application and the liquid crystal response speed are considerably faster than the normal driving method in order to increase the brightness.

First, a red data signal Rd1 and a green data signal Gd1 are provided by a data driver (not shown) of the liquid crystal display during the first sub frame period Ys1, and the first sub frame period Ys1. The yellow light source Y1 of the two-color light sources of the backlight emits light, and yellow light obtained by adding red light and green light corresponding to the red data signal Rd1 and the green data signal Gd1 is the color filter of the liquid crystal panel 108. Incident.

Thereafter, the blue data signal Bd1 is provided from the data driver during the second sub frame period Bs1, and the blue light source B1 of the backlight 107 emits light during the second sub frame period Bs1. Blue light corresponding to the data signal Bd1 is incident on the color filter of the liquid crystal panel 108.

An image is generated at each pixel of the liquid crystal panel 108 corresponding to yellow light and blue light sequentially incident from the yellow and blue light sources R1 + G1 = Y1 and B1 into the liquid crystal panel 108.

As such, the data signals Rd1 and Gd1 for red and green are sequentially provided to each pixel of the liquid crystal panel 108 during the first sub frame period Ys1, and then the second sub frame period Bs1. While the data signal Bd1 for blue is provided sequentially.

The yellow and blue light sources Y1 and B1 of the backlight 107 are sequentially driven so that the yellow and blue light sources Y1 and B1 are sequentially provided to the liquid crystal panel 108.

In this case, the yellow light source Y1 provides yellow light to the color filter of the liquid crystal panel 108 during the first sub frame period Ys1, and the blue light source B1 is the second sub frame period Bs1. Blue light is supplied to the color filter of the liquid crystal panel 108.

As a result, the liquid crystal panel 108 displays an image corresponding to the R, G, and B data signals Rd1, Gd1, and Bd1 provided during one frame.

5 illustrates a color filter of the liquid crystal display of the present invention.

As shown in FIG. 5, the color filter is composed of different mixed colors. For example, red and blue color filters (hereinafter, referred to as "first color filters") and green and blue color filters (hereinafter referred to as "second color filters"). Are alternately arranged.

As a result, a large amount of spectrum can be sent to the liquid crystal display by using two color filters to send the space to the three color filters. That is, it is possible to have a light transmittance and luminance 1.5 (3/2) times higher than using the conventional R, G, B color filters.

As mentioned above, in addition to the different mixed colors, red and green color filters are also possible.

When the yellow light shines on the first color filter and the blue light shines on the second color filter, the first and second color filters transmit only the color emitted from the backlight 107 in the first and second color filters. The color appears through the first color filter. In addition, the blue color is transmitted through the second color filter to give color.

As the screen is composed of the first and second sub-frames Ys1 and Bs1, the time for turning on each light source in the first and second sub-frame periods Ys1 and Bs1 is three light sources R, G, It will be longer when using B).

As the time for turning on the yellow light source 1 is increased, a higher light transmittance can be obtained, thereby increasing the luminance.

On the other hand, the field sequential liquid crystal display according to an embodiment of the present invention can display a high brightness as the time to turn on the yellow light source (Y1) increases, but the pupil is fixed to the liquid crystal panel in which a predetermined image is displayed. At this time, when the pupil moves or the screen moves momentarily, the color of the image displayed on the liquid crystal panel is separated.

This is called color separation phenomenon, or color break-up (CBU) phenomenon. This phenomenon occurs when the eyes move instantaneously, the screen itself shakes, and a specific image in the screen moves at a high speed.

6 illustrates a field sequential liquid crystal display according to another exemplary embodiment of the present invention.

The present invention is an invention designed to overcome the color separation phenomenon shown in one embodiment of the present invention.

As shown in FIG. 6, the field sequential liquid crystal display includes a plurality of pixels arranged in a matrix, each pixel includes a liquid crystal cell, and light transmission of the pixel is performed according to a voltage applied to each pixel electrode. A liquid crystal panel 208 controlled by a liquid crystal cell, a yellow light source Y1 positioned at the rear of the liquid crystal panel 208 and emitting yellow light in which red and green are combined at one end of the light guide plate 205; A blue light source B1 emitting blue light and a white light source W1 emitting white light are provided. The field sequential liquid crystal display further includes a color filter (not shown).

Since the color filter is the same as mentioned above, a detailed description thereof will be omitted.

In addition, the field sequential liquid crystal display device uses the light guide plate 205 to transmit yellow light, blue light and white light from the three color light sources R1 + G1 = Y1, B1, W1 to the entire surface of the liquid crystal panel 208. It further includes a backlight 207 to uniformly guide the illumination of the liquid crystal panel 108.

The white light source W1 may generate white light by simultaneously emitting the yellow light source Y1 and the blue light source B1.

7A and 7B illustrate a driving method of the field sequential liquid crystal display of FIG. 6.

As shown in FIGS. 7A and 7B, the method of driving the field sequential liquid crystal display divides one frame into three subframes. That is, one frame is divided into three subframes so that the first subframe is the yellow subframe period Ys1, the second subframe is the blue subframe period Bs1, and the third subframe is the white subframe period Ws1. To be assigned.

The yellow light source Y1 is driven in the first subframe, the blue light source B1 is driven in the second subframe, and the white light source W1 is driven in the last third subframe.

First, a red data signal R1 and a green data signal G1 are supplied to the liquid crystal panel 208 from a data driver (not shown) of the liquid crystal display during the yellow sub frame period Ys1 which is the first sub frame. During the yellow sub frame period Ys1, the yellow light source Y1 of the backlight 207 emits light, and yellow light corresponding to the red data signal R1 and the green data signal G1 is emitted from the liquid crystal panel 208. It enters into a color filter.

The blue data signal Bd1 is supplied to the liquid crystal panel 208 from the data driver during the blue sub frame period Bs1, which is the second sub frame, and the blue light source B1 of the backlight 207 during this period. ) Emits light and blue light corresponding to the blue data signal Bd1 is incident on the color filter of the liquid crystal panel 208.

Finally, the white data signal Wd1 is provided to the liquid crystal panel 208 by the data driver during the white subframe period Ws1 which is the third subframe, and during this period, the white light source of the backlight 207 is applied. W1) emits light and white light corresponding to the white data signal Wd1 is incident on the color filter of the liquid crystal panel 208.

Each of these subframes is divided into a data application time AP, a liquid crystal response time WP, and a backlight emission time FP.

As a result, the backlight of the field sequential liquid crystal display increases the luminance rather than being constituted by one frame. In the driving method of the field sequential liquid crystal display, the data application and the liquid crystal response speed are considerably faster than the normal driving method in order to increase the brightness.

Yellow and blue light are sequentially supplied from the yellow and blue light sources Y1 and B1 of the backlight 207 to the color filter on the liquid crystal panel 208 to generate color at each pixel of the liquid crystal panel 208. White light is provided from the white light source W1 on the liquid crystal panel 208 to reduce the sharpness of the generated color.

Therefore, red, green, blue, and white data signals R1, G1, B1, and W1 are sequentially provided one by one within a frame period, and from the yellow and blue light sources Y1 and B1 of the backlight 207 corresponding thereto. Yellow and blue light are provided sequentially. Since white light is continuously provided from the white light source W1, the sharpness of the color generated by the yellow and blue light is reduced as it is mixed with the white light.

As a result, the above-mentioned color separation (CBU) phenomenon may be overcome to improve image quality.

That is, the color separation (CBU) phenomenon, which is a phenomenon that is separated into three colors due to the instantaneous movement of the eyes, provides the white light by adding the white subframe, thereby reducing the sharpness of the color generated by the yellow and blue light. As the sharpness of the portion where the color is separated is reduced, color separation may not be easily recognized.

As a result, the field sequential liquid crystal display of the present invention reduces the sharpness of colors generated by yellow and blue light by adding a white subframe to one frame, thereby preventing color separation, that is, color separation (CBU) phenomenon. Overcome can improve image quality.

As described above, the field sequential liquid crystal display device may generate white light by simultaneously driving the yellow light source Y1 and the blue light source B1 without providing a separate white light source W1.

That is, as mentioned above, when the white data signal Wd1 generated by the data driver during the last sub frame period is provided to the liquid crystal panel by assigning one frame to three sub frames, the yellow light source of the backlight 207 ( Y1) and the blue light source B1 simultaneously emit light so that white light corresponding to the white data signal Wd1 is incident on the liquid crystal panel 208.

That is, the yellow light source Y1 and the blue light source B1 are simultaneously driven to generate white light so that the white light is supplied to the liquid crystal panel 208 during the third sub frame period.

During the first and second sub frame periods Ys1 and Bs1, yellow and blue light are sequentially supplied from the yellow and blue (Y1 and B1) onto the liquid crystal panel 208 to provide each pixel of the liquid crystal panel 208. Generates color and reduces the sharpness of the generated color by white light generated by simultaneously driving the yellow light source Y1 and the blue light source B1 during the third sub frame period Ws1.

Accordingly, the red, green, and blue data signals Rd1, Gd1, and Bd1 are sequentially supplied to the liquid crystal panel 208 one by one in the data driver within one frame period, and the yellow and blue light sources of the backlight 207 corresponding thereto are provided. Yellow and blue light are sequentially provided from Y1, B1).

When the data driver continuously provides the white data signal Wd1 to the liquid crystal panel 208, the white light generated by driving the yellow light source Y1 and the blue light source B1 simultaneously is transferred to the liquid crystal panel 208. The sharpness of the color produced by the yellow and blue light is thus reduced as it is mixed with the white light.

As a result, the color separation (CBU) phenomenon may be overcome to improve image quality.

In the field sequential liquid crystal display according to the exemplary embodiment of the present invention, light is emitted in the order of yellow, blue, and white, but light may be emitted in any order among a plurality of subframes constituting one frame. It is also possible to emit the white light in any subframe as well as the first or last subframe.

As mentioned above, the field sequential liquid crystal display according to the present invention overcomes the color separation (CBU) phenomenon caused by the conventional field sequential liquid crystal display by adding white subframes to yellow and blue subframes within one frame. Can improve.

As described above, the field sequential liquid crystal display according to the present invention increases the time to turn on the backlight in one frame, and adds the white sub-frame to the yellow and blue sub-frames in one frame. The image quality can be improved by overcoming the color separation (CBU) phenomenon that occurs in.

Claims (10)

Two color filters having different mixed colors; A backlight having a yellow light source, a blue light source and a white light source emitting yellow, blue and white light; And And a liquid crystal panel configured to display an image according to the light sequentially generated in the backlight. Two color filters having different mixed colors; A backlight having yellow and blue light sources emitting yellow and blue light; And And a liquid crystal panel configured to display an image according to the light sequentially generated in the backlight. Alternately arranging two color filters having different mixed colors; Dividing a frame into a plurality of subframes; Emitting yellow and blue light in two subframes of the plurality of subframes; And And emitting white light in the remaining subframes other than the two subframes among the plurality of subframes. The method of claim 3, wherein And sequentially changing the light emission order of the yellow and blue light within a subframe of one frame. The method of claim 3, wherein And the white light is emitted in an arbitrary subframe of a plurality of subframes of one frame. The method of claim 3, wherein And the white light is emitted from the last subframe of the plurality of subframes of one frame. Alternately arranging two color filters having different mixed colors; Dividing a frame into a plurality of subframes; Sequentially emitting yellow and blue light in two subframes of the plurality of subframes; And And simultaneously emitting the yellow and blue light in the remaining subframes other than the two subframes among the plurality of subframes. The method of claim 7, wherein And sequentially changing the light emission order of the yellow and blue light within a subframe of one frame. The method of claim 7, wherein And the white light is emitted in an arbitrary subframe of a plurality of subframes of one frame. The method of claim 7, wherein And the white light is emitted from the last subframe of the plurality of subframes of one frame.

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