Apparatus and method for driving liquid crystal display device

• US 20070182682A1
• Filed: 12/05/2006
• Published: 08/09/2007
• Est. Priority Date: 02/09/2006
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Kwon, Kyung Joon, Hong, Hee Jung
• Granted Patent: US 7,782,283 B2
• Time in Patent Office: Days
• US Class Current: 345/88
• CPC Class Codes: G02F 1/133613 characterized by the sequence of light sources
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

An apparatus and method for driving an LCD device is provided. The apparatus includes an LCD panel that is comprised of red, green, blue and white sub-pixels. A data converter converts input data of three colors into input data of four colors. A data driver converts the input data of four colors into a video signal, and supplies the video signal to each sub-pixel. A gate driver supplies a scan pulse to each sub-pixel. A timing controller arranges the input data of four colors supplied from the data converter and then supplies the arranged data to the data driver. A backlight unit is comprised of LEDs of at least five colors to emit the light to the LCD panel. A backlight controller controls the backlight unit in accordance with the input data of three colors and the sub-frame control signal.

Claims

1. An apparatus that drives an LCD device comprising:

an LCD panel that includes red, green, blue and white sub-pixels;

a data converter that converts input data of three colors into input data of four colors;

a data driver that is operative to convert the input data of four colors into a video signal, and supply the video signal to each sub-pixel;

a gate driver that supplies a scan pulse to each sub-pixel;

a timing controller that is operative to arrange the input data of four colors for at least three sub-frames, supply the arranged data to the data driver, and generate a sub-frame control signal corresponding to each sub-frame;

a backlight unit that includes LEDs of at least five colors; and

a backlight controller that controls the backlight unit in accordance with the input data of three colors and the sub-frame control signal.

2. The apparatus of claim 1, wherein the data converter includes:

a data amplifying unit that generates amplified data of three colors by multiplying the input data of three colors and a gain value;

a white-data extracting unit that extracts white data from the amplified data of three colors; and

a subtracting unit that subtracts the white data from the amplified data of three colors supplied from the data amplifying unit,

wherein the input data of four colors corresponds to the first to third input data and the white data.

3. The apparatus of claim 1, wherein the timing controller includes:

a data arranging unit that arranges the four-color data for one frame supplied from the data converter in four-color data for three sub-frames, and supplies the arranged four-color data to the data driver;

a synchronization signal controlling unit that converts a first synchronization signal into a second synchronization signal corresponding to the at least three sub-frames; and

a control signal generating unit that generates a data control signal that controls the data driver, a gate control signal that controls the gate driver, and the sub-frame control signal by the at least three sub-frames by using the second synchronization signal.

4. The apparatus of claim 1, wherein the backlight controller includes:

a color-ratio discriminating unit which generates at least two of a cyan-color ratio signal, a yellow-color ratio signal and a magenta-color ratio signal in accordance with at least two of a cyan-color ratio, a yellow-color ratio and a magenta-color ratio from the input data of three colors; and

a dimming signal setting unit that generates at least two dimming signals corresponding to the at least two ratio signals in accordance with the sub-frame control signal, and generates the set three-color dimming signals.

5. The apparatus of claim 4, wherein the cyan-color ratio signal is generated by the ratio of green/red to blue/red, the yellow-color ratio signal is generated by the ratio of green/blue to red/blue, and the magenta-color ratio signal is generated by the ratio of red/green to blue/green.

6. The apparatus of claim 4, wherein the backlight unit includes:

a plurality of LED arrays, each LED array provided with at least two of cyan, yellow and magenta LEDs, and three-color LEDs of red, green and blue colors; and

an LED array driver that generates red, green and blue light emission signals to drive the three-color LEDs of red, green and blue colors in accordance with the three-color dimming signals, and generates at least two of cyan, yellow and magenta light emission signals to drive the at least two-color LEDs of cyan, yellow and magenta colors in accordance with the at least two-color dimming signals.

7. The apparatus of claim 6, wherein the plurality of LED arrays are provided with the at least two of the cyan, yellow and magenta LEDs, and the three red, green and blue LEDs,

the first sub-frame of one frame displays the three-color image by transmitting the white light generated from the three-color LEDs through the red, green, blue and white sub-pixels;

the second sub-frame of one frame displays the first-color image by transmitting the first-color light generated from the first-color LED in the LEDs of two colors through the white sub-pixel; and

the third sub-frame of one frame displays the second-color image by transmitting the second-color light generated from the second-color LED in the LEDs of two colors through the white sub-pixel.

8. The apparatus of claim 6, wherein the plurality of LED arrays are provided with the at least two of the cyan, yellow and magenta LEDs, and the three-color LEDs of red, green and blue LEDs,

the first sub-frame of one frame displays the three-color image by transmitting the white light generated from the three-color LEDs through the red, green, blue and white sub-pixels;

the second sub-frame of one frame displays the first-color image by transmitting the first-color light generated from the first-color LED corresponding to any one of the at least two of the cyan, yellow and magenta LEDs through the white sub-pixel;

the third sub-frame of one frame displays the second-color image by transmitting the second-color light generated from the second-color LED corresponding to another of the cyan, yellow and magenta LEDs through the white sub-pixel; and

the fourth sub-frame of one frame displays the third-color image by transmitting the third-color light generated from the third-color LED corresponding to the third of the cyan, yellow and magenta LEDs through the white sub-pixel.

9. An apparatus for driving an LCD device comprising:

an LCD panel that includes red, green, blue and white sub-pixels;

a data converter that is operative to convert input data of three colors into input data of four colors;

a data driver that is operative to convert the input data of four colors into a video signal, and supply the video signal to each sub-pixel;

a gate driver that supplies a scan pulse to each sub-pixel;

a timing controller that is operative to arrange the input data of four colors for at least three sub-frames, supply the arranged data to the data driver, and generate a sub-frame control signal corresponding to each sub-frame;

a backlight unit that includes at least one lamp and at least two LEDs; and

a backlight controller that controls the backlight unit in accordance with the input data of three colors and the sub-frame control signal.

10. The apparatus of claim 9, wherein the data converter includes:

a data amplifying unit that generates amplified data of three colors by multiplying the input data of three colors and a gain value;

a white-data extracting unit that extracts white data from the amplified data of three colors; and

a subtracting unit that subtracts the white data from the amplified data of three colors supplied from the data amplifying unit,

wherein the input data of four colors corresponds to the first to third input data and the white data.

11. The apparatus of claim 9, wherein the timing controller includes:

a data arranging unit that is operative to arrange the four-color data for one frame supplied from the data converter in four-color data for three sub-frames, and supply the arranged four-color data to the data driver;

a synchronization signal controlling unit that converts a first synchronization signal into a second synchronization signal corresponding to the at least three sub-frames; and

a control signal generating unit that generates a data control signal that controls the data driver, a gate control signal that controls the gate driver, and the sub-frame control signal that controls at least three sub-frames by using the second synchronization signal.

12. The apparatus of claim 9, wherein the backlight controller includes:

a color-ratio discriminating unit that generates at least two of a cyan-color ratio signal, a yellow-color ratio signal and a magenta-color ratio signal in accordance with at least two of a cyan-color ratio, a yellow-color ratio and a magenta-color ratio from the input data of three colors; and

a dimming signal setting unit that generates a lamp dimming signal that drives the at least one lamp in accordance with the sub-frame control signal, and generates at least two dimming signals corresponding to the at least two ratio signals.

13. The apparatus of claim 12, wherein the cyan-color ratio signal is generated by the ratio of green/red to blue/red, the yellow-color ratio signal is generated by the ratio of green/blue to red/blue, and the magenta-color ratio signal is generated by the ratio of red/green to blue/green.

14. The apparatus of claim 12, wherein the backlight unit includes:

a backlight array that includes at least one lamp and the at least two of cyan, yellow and magenta LEDs; and

a backlight driver that generates a lamp driving signal that drives the lamp in accordance with the lamp dimming signal, and generates at least two light emission signals that drive the at least two LEDs

15. The apparatus of claim 14, wherein the backlight array includes:

a light-guiding plate having lateral sides, which correspond to incidence sides to guide the incident light, toward the LCD panel;

the lamp faces at least one side of the light-guiding plate;

at least one LED array faces the other sides of the light-guiding plate having no lamp, each LED array provided with LEDs of at least two colors; and

a plurality of optical sheets which are arranged above the light-guiding plate.

16. The apparatus of claim 14, wherein the backlight array includes:

a light-diffusion plate that diffuses the incident light,

wherein the plurality of lamps are arranged on the rear surface of the light-diffusion plate at fixed intervals in one direction;

a plurality of LED arrays that are provided between each of the lamps, wherein each LED array is provided with LEDs of at least two colors; and

a plurality of optical sheets are provided above the light-diffusion plate.

17. The apparatus of claim 14, wherein the backlight array is provided with the at least two of the cyan, yellow and magenta LEDs, and the at least one lamp,

the first sub-frame of one frame displays the three-color image and transmits the white light generated from the lamp through the red, green, blue and white sub-pixels;

the second sub-frame of one frame displays the first-color image and transmits the first-color light generated from the first-color LED in the LEDs of two colors through the white sub-pixel; and

the third sub-frame of one frame displays the second-color image and transmits the second-color light generated from the second-color LED in the LEDs of two colors through the white sub-pixel.

18. The apparatus of claim 14, wherein the backlight array is provided with the cyan, yellow and magenta LEDs, and the at least one lamp,

the first sub-frame of one frame displays the three-color image and transmits the white light generated from the lamp through the red, green, blue and white sub-pixels;

the second sub-frame of one frame displays the first-color image and transmits the first-color light generated from the first-color LED corresponding to any one of the cyan, yellow and magenta LEDs through the white sub-pixel;

the third sub-frame of one frame displays the second-color image and transmits the second-color light generated from the second-color LED corresponding to another of the cyan, yellow and magenta LEDs through the white sub-pixel; and

the fourth sub-frame of one frame displays the third-color image and transmits the third-color light generated from the third-color LED, which corresponds to the third of the cyan, yellow and magenta LEDs through the white sub-pixel.

19. A method that drives an LCD device including an LCD panel provided with red, green, blue and white sub-pixels comprising:

converting input data of three colors into input data of four colors;

arranging the four-color data of each frame in four-color input data for at least three sub-frames, and supplying the arranged four-color data to the data driver, and generating a sub-frame control signal corresponding to each sub-frame;

supplying a scan pulse to each sub-pixel;

converting the four-color input data into a video signal, and supplying the video signal to each sub-pixel in synchronization with the four-color input data; and

driving a backlight unit that has LEDs of at least five colors in accordance with the three-color input data and the sub-frame control signal, to thereby emit the light to the LCD panel.

20. The method of claim 19, wherein converting input data of three colors into input data of four colors includes:

generating amplified data of three colors by multiplying the input data of three colors inputted externally and a gain value inputted externally;

extracting white data out of the amplified data of three colors; and

generating first to third color input data by subtracting the white data from the amplified data of three colors, wherein the input data of four colors correspond to the first to third color input data and the white data.

21. The method of claim 19, wherein arranging the four-color data of each frame in four-color input data for at least three sub-frames includes:

converting a first synchronization signal externally inputted into a second synchronization signal that corresponds to the at least three sub-frames; and

generating a gate control signal to supply a scan pulse to each sub-pixel, and a data control signal to supply a video signal to each sub-pixel by using the second synchronization signal.

22. The method of claim 19, wherein driving a backlight unit that has LEDs of at least five colors includes:

generating at least two of a cyan-color ratio signal, a yellow-color ratio signal and a magenta-color ratio signal in accordance with at least two of a cyan-color ratio, a yellow-color ratio and a magenta-color ratio from the input data of three colors;

generating at least two dimming signals that correspond to the at least two ratio signals in accordance with the sub-frame control signal, and generating the set three-color dimming signals; and

generating red, green and blue light emission signals to drive the red, green and blue LEDs in accordance with the three-color dimming signals, and at least two of cyan, yellow and magenta light emission signals to drive the at least two of the cyan, yellow and magenta LEDs in accordance with the at least two dimming signals.

23. The method of claim 22, wherein the cyan-color ratio signal is generated by the ratio of green/red to blue/red, the yellow-color ratio signal is generated by the ratio of green/blue to red/blue, and the magenta-color ratio signal is generated by the ratio of red/green to blue/green.

24. The method of claim 22, wherein the one frame is provided with the first to third sub-frames,

the first sub-frame displays the three-color image and transmits the white light generated from the three-color LEDs through the red, green, blue and white sub-pixels;

the second sub-frame displays the first-color image and transmits the first-color light generated from the first-color LED in the LEDs of two colors through the white sub-pixel; and

the third sub-frame displays the second-color image and transmits the second-color light generated from the second-color LED in the LEDs of two colors through the white sub-pixel.

25. The method of claim 22, wherein the one frame is provided with the first to fourth sub-frames,

the first sub-frame displays the three-color image and transmits the white light generated from the three-color LEDs through the red, green, blue and white sub-pixels;

the second sub-frame displays the first-color image and transmits the first-color light generated from the first-color LED corresponding to any one of the cyan, yellow and magenta LEDs through the white sub-pixel;

the third sub-frame displays the second-color image and transmits the second-color light generated from the second-color LED corresponding to another of the cyan, yellow and magenta LEDs through the white sub-pixel; and

the fourth sub-frame displays the third-color image and transmits the third-color light generated from the third-color LED corresponding to the third of the cyan, yellow and magenta LEDs through the white sub-pixel.

26. A method for driving an LCD device including an LCD panel provided with red, green, blue and white sub-pixels comprising:

converting input data of three colors into input data of four colors;

arranging the four-color data of each frame in four-color input data for at least three sub-frames, and supplying the arranged four-color data to the data driver, and generating a sub-frame control signal corresponding to each sub-frame;

supplying a scan pulse to each sub-pixel;

converting the four-color input data into a video signal, and supplying the video signal to each sub-pixel in synchronization with the four-color input data; and

driving backlight unit having at least one lamp and at least two LEDs in accordance with the three-color input data and the sub-frame control signal, to thereby emit the light to the LCD panel.

27. The method of claim 26, wherein converting input data of three colors into input data of four colors includes:

generating amplified data of three colors by multiplying the input data of three colors inputted externally and a gain value inputted externally;

extracting white data out of the amplified data of three colors; and

generating first to third color input data by subtracting the white data from the amplified data of three colors, wherein the input data of four colors correspond to the first to third color input data and the white data.

28. The method of claim 26, wherein arranging the four-color data of each frame in four-color input data for at least three sub-frames includes:

converting a first synchronization signal externally inputted into a second synchronization signal that corresponds to the at least three sub-frames; and

generating a gate control signal to supply a scan pulse to each sub-pixel, and a data control signal to supply a video signal to each sub-pixel by using the second synchronization signal.

29. The method of claim 26, wherein driving the backlight unit having at least one lamp and at least two LEDs includes:

generating at least two of a cyan-color ratio signal, a yellow-color ratio signal and a magenta-color ratio signal in accordance with at least two of a cyan-color ratio, a yellow-color ratio and a magenta-color ratio from the input data of three colors;

generating a lamp dimming signal to drive the at least one lamp, and at least two dimming signals that correspond to the at least two ratio signals in accordance with the sub-frame control signal; and

generating a lamp driving signal to drive the lamp in accordance with the lamp dimming signal, and at least two light emission signals to drive the at least two of cyan, yellow and magenta LEDs in accordance with the at least two dimming signals.

30. The method of claim 29, wherein the cyan-color ratio signal is generated by the ratio of green/red to blue/red, the yellow-color ratio signal is generated by the ratio of green/blue to red/blue, and the magenta-color ratio signal is generated by the ratio of red/green to blue/green.

31. The method of claim 29, wherein the one frame is provided with the first to third sub-frames,

the first sub-frame displays the three-color image and transmits the white light generated from the lamp through the red, green, blue and white sub-pixels;

the second sub-frame displays the first-color image and transmits the first-color light generated from the first-color LED in the LEDs of two colors through the white sub-pixel; and

the third sub-frame displays the second-color image and transmits the second-color light generated from the second-color LED in the LEDs of two colors through the white sub-pixel.

32. The method of claim 29, wherein the one frame is provided with the first to fourth sub-frames,

the first sub-frame displays the three-color image and transmits the white light generated from the lamp through the red, green, blue and white sub-pixels;

the second sub-frame displays the first-color image and transmits the first-color light generated from the first-color LED corresponding to any one of the cyan, yellow and magenta LEDs through the white sub-pixel;

the third sub-frame displays the second-color image and transmits the second-color light generated from the second-color LED corresponding to another of the cyan, yellow and magenta LEDs through the white sub-pixel; and

the fourth sub-frame displays the third-color image and transmits the third-color light generated from the third-color LED corresponding to the third of the cyan, yellow and magenta LEDs through the white sub-pixel.