KR20060114473A - Liquid crystal display device - Google Patents

Abstract

An LCD is provided to supplement an image displayed by red, green, and blue sub-pixels, by applying white data signals corresponding to gray level of color which red, green, and blue sub-pixels display, and then sequentially applying red, green, and blue lights to a white sub-pixel. An LCD comprises a pixel composed of red, green, blue, and white sub-pixels, a light source unit composed of red, green, blue, and white light emitting diodes, and a light source controller(400). The light source controller outputs control signals corresponding to scan signals, which are outputted from a scan driver(200) to the red, green, blue, and white light emitting diodes respectively. The LCD applies white light to the red, green, and blue sub-pixels to display a desired color, and sequentially applies red, green, and blue lights to the white sub-pixel to display the same color as the desired color.

Description

Liquid Crystal Display Device

1 is a block diagram of a conventional liquid crystal display device.

2 is a block diagram of a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a block diagram of a light source controller according to an exemplary embodiment of the present invention.

4 is a timing diagram illustrating an operation of a liquid crystal display according to an exemplary embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

100: pixel portion

200: scan driver

300: data driver

400: light source control unit

500: light source

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device including a pixel portion composed of red, green, blue, and white subpixels, and a light source portion composed of red, green, blue, and white light emitting diodes. The present invention relates to a liquid crystal display including a light source controller for controlling a light emitting diode of the light source unit according to a scan signal applied to a pixel.

In general, a liquid crystal display device (LCD) displays an image by adjusting an optical transmittance by changing an arrangement of liquid crystals having dielectric anisotropy using an electric field. When the liquid crystal display displays a multi-color image The liquid crystal display includes a color filter of red, green, and blue, and one pixel is divided into red, green, and blue color filters. Consists of blue subpixels.

1 is a block diagram of a conventional liquid crystal display device.

Referring to FIG. 1, the liquid crystal display device includes a pixel unit 10, a scan driver 20, a data driver 30, and a light source unit 40.

The pixel unit 10 includes a plurality of pixels P11 to Pnm formed in an area where a plurality of data lines DR1 to DWm and a plurality of scan lines S1 to Sn cross each other, and a plurality of pixels P11. Pnm) is composed of red, green and blue subpixels (PR, PG, PB).

The scan driver 20 receives a scan control signal, that is, a start pulse and a clock signal from a timing controller (not shown), generates a scan signal, and sequentially applies the generated scan signals to the plurality of scan lines S1 to Sn. .

The data driver 30 receives the data control signal and the red, green, and blue data signals from the timing controller (not shown), and sequentially applies the red, green, and blue data signals to the plurality of data lines D1 to Dm.

The light source unit 40 includes a plurality of white light emitting diodes, and provides light of a constant brightness to the pixel unit 10 regardless of the luminance of the input image signal.

Referring to the operation of the liquid crystal display, the white light emitting diode of the light source unit 40 is turned on to irradiate white light to the pixel unit, and a high level scan signal is applied to the thin film transistor of the pixel Pnm. Thereafter, when the red, green, and blue data signals are sequentially applied to the pixels Pnm from the data driver 30, the arrangement of the liquid crystal layers is changed according to each data signal, thereby emitting white light having a specific luminance. This white light passes through the red, green and blue color filters to have red, green and blue colors of specific brightness. The pixel Pnm combines the lights of red, green and blue colors of this particular luminance to display a predetermined color.

However, the color of white light emitted from the white light emitting diode of the liquid crystal display device passing through the red, green, and blue color filters and displayed on each subpixel depends on the transmittance of the color filter and the relative radiation amount of the white light emitting diode.

Therefore, the color saturation is low due to the lack of saturation and luminance, there was a problem that a defect occurs.

An object of the present invention for solving the above problems is according to the pixel portion composed of red, green, blue and white sub-pixel, the light source portion composed of red, green, blue and white light emitting diode and the scanning signal applied to the pixel portion. The present invention provides a liquid crystal display device including a light source controller for controlling a light emitting diode of the light source unit.

According to an aspect of the present invention, a pixel unit for displaying a predetermined image including a plurality of pixels including red, green, blue, and white subpixels, a first scan signal, and a following scan signal A scan driver for supplying a second scan signal, a third scan signal following the second scan signal, and a fourth scan signal following the third scan signal, red, green, and the like when the first scan signal is applied to the pixel portion. A data driver for supplying red, green, and blue data signals to the blue subpixel, respectively, and for supplying the white data signal to the white subpixel when the second, third, and fourth scan signals are applied, and a control signal according to the displayed image. And a light source unit for emitting light to the pixel unit by performing a light emitting operation according to a control signal of the light source controller for generating a All.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Example

2 is a block diagram of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the liquid crystal display of the present invention includes a plurality of pixels P11 to Pnm composed of red, green, blue, and white subpixels, and includes a pixel portion 100 and a pixel for displaying a predetermined image. A scan driver 200 for supplying a scan signal to the unit 100, a data driver 300 for supplying a data signal to the pixel unit 100, a light source controller for generating a control signal according to the displayed image ( 400 and a light source unit 500 which emits light to the pixel unit by performing a light emission operation according to a control signal of the light source controller 400.

The pixel unit 100 includes a plurality of pixels P11 to Pnm formed in an area where a plurality of data lines DR1 to DWm and a plurality of scan lines S1 to Sn intersect each pixel. Has a liquid crystal for. These pixels Pnm are divided into red, green, blue, and white subpixels PR, PG, PB, and PW by red, green, blue, and white color filters.

The red, green, blue, and white subpixels PR, PG, PB, and PW are arranged in a stripe structure. In the stripe structure, red, green, blue, and white subpixels (PR, PG, PB, and PW) are arranged in a line, and a driving integrated circuit is mounted on one side of the pixel unit 100 to drive integration on both sides of the pixel unit 100. It is possible to prevent defects such as crosstalk and flicker that may occur when mounting circuits.

Each pixel Pnm displays a specific color for each pixel by combining red, green, blue, and white light having a specific luminance represented by the subpixels PR, PG, PB, and PW.

The scan driver 200 receives a scan control signal, that is, a start pulse and a clock signal from a timing controller (not shown), and transmits a scan signal through a plurality of scan lines S1 -Sn to the plurality of pixels of the pixel unit 100 ( P11 ~ Pnm). The scan driver 200 may include a shift register composed of a plurality of flip-flops.

The scan signal is followed by a first scan signal for dividing one frame into four subframes, a second scan signal following the first scan signal, a third scan signal following the second scan signal, and a third scan signal. Is composed of a fourth scanning signal. When the first scan signal is applied, the red, green, and blue subpixels of the pixel unit 100 display an image corresponding to the applied data value. Then, when the second, third and fourth scan signals are applied, the white subpixel of the pixel portion 100 complements the displayed image when the first scan signal is applied.

The data driver 300 receives a data control signal, that is, a start pulse and a clock signal, and red, green, blue, and white data signals from a timing controller (not shown). When the first scan signal is applied to the pixel unit 100, the data driver 300 sequentially applies red, green, and blue data signals to the red, green, and blue subpixels of the pixel unit 100. Next, when the second, third and fourth scan signals are applied to the pixel unit 100, the respective data signals are sequentially applied to the white subpixels of the pixel unit 100.

The light source unit 500 includes a plurality of red, green, blue, and white light emitting diodes, and emits a combination of red, green, blue, and white light to the pixel unit under the control of the light source controller 400.

The light source controller 400 is controlled by the scan driver 200 to output control signals of red, green, blue, and white light emitting diodes to the light source 500.

3 is a block diagram of a light source controller according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the light source controller 400 of FIG. 2 includes an LED controller 410, a first controller 430, and a second controller 450.

The LED controller 410 receives a light source control signal from the scan driver 200. The LED controller 410 outputs a first control signal for controlling the on / off operation of the first controller 430 to the first controller 430 while the first scan signal is applied to the pixel unit 100. Thereafter, while the second, third and fourth scan signals are output, the second control signal for controlling the operation of the second control unit 450 is output to the second control unit 450.

The first controller 430 receives the first control signal from the LED controller 410 and outputs the W control signal to the white light emitting diode of the light source unit 500. The W control signal is applied while the first scan signal is output to the pixel unit 100 and has a voltage that turns on the white light emitting diode.

The second controller 450 receives the second control signal from the LED controller 410 and sequentially applies the R, G, and B control signals to the red, green, and white light emitting diodes of the light source unit 100. The R control signal is applied while the second scan signal is output to the pixel unit 100 and has a voltage that turns on the red light emitting diode.

The G control signal is applied while the third scan signal is output to the pixel unit 100, and has a voltage that turns on the green light emitting diode.

The B control signal is applied while the fourth scan signal is output to the pixel unit 100, and has a voltage that turns on the blue light emitting diode.

Accordingly, the second control signal applied from the LED controller 410 turns on the red light emitting diode by turning on the red light emitting diode when the second scan signal is applied, and turns off the green and blue light emitting diode. Next, when the third scan signal is applied, the green light emitting diode is turned on by applying a turn-on voltage to the green light emitting diode, and the red and blue light emitting diodes are turned off. Finally, when the fourth scan signal is applied, the turn-on voltage is applied to the blue light emitting diode to turn on the blue light emitting diode, and turn off the red and green light emitting diodes.

4 is a timing diagram illustrating an operation of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the operation of the liquid crystal display of FIGS. 2 and 3 will be described. The scan driver 200 supplies the first to nth first scan signals to the pixel unit 100. The LED controller 410 of the light source controller 400 supplies the first control signal to the first controller 430 while the first scan signal is supplied. The first controller 430 outputs the W control signal to the white light emitting diode of the light source unit 500 according to the first control signal to irradiate the white light to the pixel unit 100.

When the first scan signal Sn having a high level is applied from the scan driver 200 to the thin film transistor of the red subpixel PRnm of the pixel, the thin film transistor of the red subpixel PRnm is turned on. When the thin film transistor of the red subpixel PRnm is turned on, the red data signal DRm is applied from the data driver 300. When a data voltage corresponding to the red data signal DRm is applied to the pixel electrode of the liquid crystal layer, the liquid crystals are arranged at corresponding slopes.

Therefore, the white light passing through the liquid crystal layer has a luminance corresponding to the red data signal DRm and passes through the red color filter to display red having a specific luminance in the red subpixel PRnm.

Next, when the high level first scan signal Sn is applied from the scan driver 200 to the thin film transistor of the green subpixel PGnm of the pixel, the thin film transistor of the green subpixel PGnm is turned on. When the thin film transistor of the green subpixel PGnm is turned on, the green data signal DGm is applied from the data driver 300. When a data voltage corresponding to the green data signal DGm is applied to the pixel electrode of the liquid crystal layer, the liquid crystals are arranged at corresponding slopes.

Accordingly, the white light passing through the liquid crystal layer has luminance corresponding to the green data signal DGm, and passes through the green color filter to display green having a specific luminance in the green subpixel PGnm.

Finally, when the first scan signal Sn having a high level is applied from the scan driver 200 to the thin film transistor of the blue subpixel PBnm of the pixel, the thin film transistor of the blue subpixel PBnm is turned on. When the thin film transistor of the blue subpixel PBnm is turned on, the blue data signal DBm is applied from the data driver 300. When a data voltage corresponding to the blue data signal DBm is applied to the pixel electrode of the liquid crystal layer, the liquid crystals are arranged at corresponding slopes.

Therefore, the white light passing through the liquid crystal layer has a luminance corresponding to the blue data signal DBm and passes through the blue color filter to display blue having a specific luminance in the blue subpixel PBnm.

While the first scan signal is applied, the pixel Pmn displays a specific color by combining the red, green, and blue colors of the red, green, and blue subpixels PRnm, PGnm, and PBnm having respective luminance.

The scan driver 200 supplies the first to nth second scan signals following the first scan signal to the pixel unit 100. The LED controller 410 of the light source controller 400 supplies the second control signal to the second controller 430 while the second scan signal is supplied. The second control unit 430 outputs the R control signal to the red light emitting diode of the light source unit 500 according to the second control signal, turns on the red light emitting diode, and irradiates red light to the pixel unit 100.

When the high level second scan signal Sn is applied to the thin film transistor of the white subpixel PWnm of the pixel from the scan driver 200, the thin film transistor of the white subpixel PWnm is turned on. When the thin film transistor of the white subpixel PWnm is turned on, the data driver 300 provides the red white data signal DWm to the white subpixel PWnm. When a data voltage corresponding to a red white data signal is applied to the pixel electrode of the liquid crystal layer, the liquid crystals are arranged at corresponding slopes. The red light emitted from the red light emitting diode (R LED) of the light source unit 500 and passed through the liquid crystal layer has a luminance corresponding to the white data signal of red, passes through the white color filter, and is specific to the white subpixel (PWnm). Red with luminance is displayed.

Next, the scan driver 200 supplies the first to nth third scan signals following the second scan signal to the pixel unit 100. The LED controller 410 of the light source controller 400 supplies the second control signal to the second controller 430 while the third scan signal is supplied. The second control unit 430 outputs the G control signal to the green light emitting diode of the light source unit 500 according to the second control signal, turns on the green light emitting diode, and irradiates the green light to the pixel unit 100.

 When the high level third scan signal Sn is applied from the scan driver 200 to the thin film transistor of the white subpixel PWnm of the pixel, the thin film transistor of the white subpixel PWnm is turned on. When the thin film transistor of the white subpixel PWnm is turned on, the data driver 300 sequentially provides the green white data signal DWm to the white subpixel PWnm. When a data voltage corresponding to the green white data signal is applied to the pixel electrode of the liquid crystal layer, the liquid crystals are arranged at corresponding slopes. The green light irradiated from the green light emitting diode (G LED) of the light source unit 500 and passed through the liquid crystal layer has a luminance corresponding to the white data signal of green, passes through the white color filter, and is specific to the white subpixel (PWnm). Green with luminance is displayed.

Finally, the scan driver 200 supplies the first to nth fourth scan signals following the third scan signal to the pixel unit 100. The LED controller 410 of the light source controller 400 supplies the second control signal to the second controller 430 while the fourth scan signal is supplied. The second control unit 430 outputs the B control signal to the blue light emitting diode of the light source unit 500 according to the second control signal, turns on the blue light emitting diode, and irradiates the blue light to the pixel unit 100.

When the fourth scan signal Sn having the high level is applied from the scan driver 200 to the thin film transistor of the white subpixel PWnm of the pixel, the thin film transistor of the white subpixel PWnm is turned on. When the thin film transistor of the white subpixel PWnm is turned on, the data driver 300 provides a blue white data signal DWm to the white subpixel PWnm. When a data voltage corresponding to a blue white data signal is applied to the pixel electrode of the liquid crystal layer, the liquid crystals are arranged at corresponding slopes. The blue light emitted from the blue light emitting diode (B LED) of the light source unit 500 and passing through the liquid crystal layer has luminance corresponding to the blue white data signal, passes through the white color filter, and passes through the white subpixel (PWnm). Displays blue with a specific brightness.

The red, green, and blue white data signals DWm refer to data voltages corresponding to gray levels of respective red, green, and blue subpixels PRnm, PGnm, and PBnm when the first scan signal is applied. .

Therefore, the white subpixel (PWnm) displays the same color as that displayed by the red, green, and blue subpixels (PRnm, PGnm, and PBnm) to compensate for the luminance and chromaticity of the color in which the pixel is displayed when the first scan signal is applied. do.

According to the present invention as described above, the sag represented by the pixel can be improved by driving the white subpixel separately. That is, a white data signal corresponding to the gradation level of the color indicated by the red, green, and blue subpixels is applied, and accordingly, the white subpixels sequentially irradiate light from the red, green, and blue light emitting diodes. Therefore, the same color as that displayed by the red, green, and blue subpixels is displayed on the white subpixel to supplement the image.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (7)

A pixel unit for displaying a predetermined image including a plurality of pixels including red, green, blue, and white subpixels; A first scan signal for dividing one frame into four subframes, a second scan signal following the first scan signal, a third scan signal following the second scan signal and a third scan signal A scan driver for supplying a fourth scan signal to the pixel portion; The red, green, and blue data signals are respectively supplied to the red, green, and blue subpixels when the first scan signal is applied to the pixel unit, and the white subpixels are applied when the second, third, and fourth scan signals are applied. A data driver for supplying a white data signal to the controller; A light source controller for generating a control signal according to the displayed image; And The light emitting operation is performed according to the control signal of the light source controller to emit white light to the pixel portion in the section where the first scan signal is applied, and to the pixel section in the section where the second, third and fourth scan signals are applied. And a light source unit emitting red, green, or blue light. The liquid crystal display of claim 1, wherein the light source unit comprises red, green, blue, and white light emitting diodes. The method of claim 2, wherein the light source control unit A first control unit controlling a light emitting operation by applying a W control signal to the white light emitting diode; A second controller configured to control an emission operation by applying an R control signal, a G control signal, and a B control signal to the red, green, and blue light emitting diodes, respectively; And A second control unit configured to receive a light source control signal from the scan driver, output a first control signal for controlling an on / off operation of the first control unit to the first control unit, and control an on / off operation of the second control unit And a LED controller for outputting a control signal to the second controller. The method of claim 3, wherein the LED control unit Outputting the first control signal to the first controller while the first scan signal is output to the pixel portion, And outputting the second control signal to the second controller while the second, third and fourth scan signals are output. The method of claim 4, wherein the first controller is configured to output a W control signal corresponding to a voltage having a magnitude of turning on the white light emitting diode while the first scan signal is output to the pixel unit according to the first control signal. Liquid crystal display device characterized in that. The method of claim 5, wherein the second control unit While the second, third, and fourth scan signals are applied to the pixel portion according to the second control signal, R, G, and B control signals corresponding to voltages for turning on the red, green, and blue light emitting diodes are sequentially applied. And a liquid crystal display device for outputting. 7. The red, green, and blue colors of claim 6, wherein the data driver is configured to configure colors displayed by the pixel while the first, second, and fourth scan signals are applied to the pixel portion. And applying a white data signal of a voltage corresponding to the gradation level of to the white subpixel.

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