LIQUID CRYSTAL DISPLAY APPARATUS AND METHOD OF DRIVING

• US 20070247560A1
• Filed: 04/09/2007
• Published: 10/25/2007
• Est. Priority Date: 04/25/2006
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Jun, Tae-Jong, Han, Jung-Suk, Lee, Joo-Young, Lee, Jong-Seo, Shin, Seong-Sik
• Granted Patent: US 7,796,114 B2
• Time in Patent Office: Days
• US Class Current: 349/46
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133622 Colour sequential illumination
• CPC Class Codes: G09G 2310/024 Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources

Abstract

A liquid crystal display (LCD) apparatus displaying a color image of a frame by dividing the frame into a plurality of periods in which different colors are displayed includes an LCD panel and light-emitting units. The light-emitting units are disposed under the LCD panel and generate lights having different colors in corresponding periods during a light-emitting interval. For example, the turn-on times of the light-emitting units are sequentially delayed as much as the voltage-transmittance response waveform of the liquid crystal is delayed from the first light-emitting unit to the last light-emitting unit. The light-emitting interval of a first region of the LCD panel ends shortly after its maximum value is reached corresponding to a first gate line of a light-emitting unit, and the light emitting interval of a second region corresponding to a last gate line of the light-emitting unit is delayed to maximize luminance.

Claims

1. A liquid crystal display (LCD) apparatus displaying a color image of a frame by dividing the frame into a plurality of periods in which different colors are displayed, the LCD apparatus comprising:

an LCD panel including a plurality of gate lines and a plurality of data lines crossing a plurality of the gate lines; and

a plurality of light-emitting units disposed under the LCD panel, the light-emitting units respectively generating lights having different colors in each of the periods during a light-emitting interval,

wherein a light-emitting ending point of the light-emitting interval is disposed between a first maximum light-transmitting time of a first region of the LCD panel and a second maximum light-transmitting time of a second region of the LCD panel, the first region corresponding to a first gate line of a light-emitting unit and the second region corresponding to a last gate line of the light-emitting unit.

2. The LCD apparatus of claim 1, wherein the LCD panel comprising:

a first substrate including the gate lines and the data lines;

a second substrate facing the first substrate; and

a liquid crystal disposed between the first and second substrates, the liquid crystal adjusting light-transmittance of light provided from the light-emitting units.

3. The LCD apparatus of claim 2, wherein the liquid crystal is driven by a potential difference between voltages applied to the first substrate and the second substrate and has a voltage-transmittance response waveform gradually increasing from an initial driving time to an ending driving time.

4. The LCD apparatus of claim 3, wherein the voltage-transmittance response waveform of the liquid crystal is sequentially delayed from the first gate line to the last gate line by a constant time.

5. The LCD apparatus of claim 4, wherein the voltage-transmittance response waveform corresponding to the first gate line has a first peak in the first maximum light-transmitting time and the voltage-transmittance response waveform corresponding to the last gate line has a second peak in the second maximum light-transmitting time.

6. The LCD apparatus of claim 5, wherein one frame is divided into four periods and each of the light-emitting unit generates red light, green light, blue light and white light in corresponding periods, respectively.

7. The LCD apparatus of claim 6, wherein the light-emitting ending point of the light-emitting interval is delayed from the first maximum light-transmitting time by about 0.15 ms to about 0.17 ms.

8. The LCD apparatus of claim 7, wherein a delay time between the first maximum light-transmitting time and the second maximum light-transmitting time is in a range of about 0.52 ms to about 0.53 ms.

9. The LCD apparatus of claim 8, wherein eight light-emitting units are disposed such that a longitudinal direction of the light-emitting units is substantially parallel to the gate lines.

10. The LCD apparatus of claim 5, wherein one frame is divided into three periods and each of the light-emitting unit generate red light, green light and blue light in corresponding periods, respectively.

11. The LCD apparatus of claim 5, wherein the light-emitting units includes a red light-emitting diode, a green light-emitting diode and a blue light-emitting diode.

12. A method of driving an LCD apparatus displaying a color image of a frame by dividing the frame into a plurality of periods in which different colors are displayed,

wherein a plurality of light-emitting units disposed under an LCD panel respectively generates lights having different colors in corresponding periods during a light-emitting interval, and a light-emitting ending point of the light-emitting interval disposed between a first maximum light-transmitting time of a first region of the LCD panel, the first region corresponding to a first gate line of a light-emitting unit, and a second maximum light-transmitting time of a second region of the LCD panel, the second region corresponding to a last gate line of the light-emitting unit.

13. The method of claim 12, wherein one frame is divided into three periods and each of the light-emitting unit generates red light, green light and blue light in corresponding periods, respectively.

14. The method of claim 13, wherein eight light-emitting units are disposed such that a longitudinal direction of the light-emitting units is substantially parallel to the gate lines, and the light-emitting units are driven so that the light-emitting ending point of the light-emitting interval is delayed from the first maximum light-transmitting time by about 0.15 ms to about 0.17 ms.

15. The method of claim 12, wherein one frame is divided into three periods and each of the light-emitting unit generate red light, green light and blue light in corresponding periods.

19. The method of claim 12 wherein the light-emitting interval is determined so that an integral value of voltage-transmittance response waveforms multiplied by light-emitting signals of light-emitting unit is maximized.

16. A method of driving an LCD apparatus displaying a color image of a frame by dividing the frame into a plurality of periods in which different colors are displayed,

wherein a plurality of light-emitting units disposed under an LCD panel respectively generates lights having different colors in corresponding periods during a light-emitting interval, and the light-emitting interval is set up so that an integral value of voltage-transmittance response waveforms multiplied by a light-emitting signal waveform is maximized, the voltage-transmittance response waveforms corresponding respectively to gate lines of a light-emitting unit, and a light-emitting signal waveform corresponding to the light-emitting unit.

17. The method of claim 16, wherein a light-emitting ending point of the light-emitting interval is disposed between a first peak of the voltage-transmittance response waveform corresponding to a first gate line of a light-emitting unit and a second peak of the voltage-transmittance response waveform corresponding to a last gate line of the light-emitting unit.

18. The method of claim 17, wherein one frame is divided into four periods, eight light-emitting units are disposed such that a longitudinal direction of the light emitting-units is substantially parallel with the gate lines, and the light-emitting units are driven so that the light-emitting ending point of the light-emitting interval is delayed from the first maximum light-transmitting time by a delay time in a range of about 0.15 ms to about 0.17 ms.