Field sequential liquid crystal display device and method of fabricating the same

• US 20040036672A1
• Filed: 06/19/2003
• Published: 02/26/2004
• Est. Priority Date: 08/23/2002
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Son, Hyeon-Ho, Yoo, Jang-Jin
• Granted Patent: US 9,153,185 B2
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A field sequential liquid crystal display device includes a circuit unit producing RGB reference voltages and scanning signal voltages using RGB data and control signals, a liquid crystal display panel changing alignment direction of liquid crystal molecules in accordance with the RGB reference voltages and the scanning signal voltages, and a backlight device emitting light to the liquid crystal display panel, wherein the circuit unit includes an interface receiving the RGB data and the control signals, a timing controller generating gate control signals and data control signals, at least two gamma generating units generating the RGB reference voltages, a switch selecting one of the RGB reference voltages, a data driver receiving the data control signal and the selected RGB reference voltage selected from the switch, and supplying an RGB image voltage to the liquid crystal display panel in accordance with the selected RGB reference voltage and the data control signal, and a gate driver receiving the gate control signals from the timing controller and supplying the scanning signal voltage to the liquid crystal display panel in accordance with the gate control signal.

Claims

1. A field sequential liquid crystal display device, comprising:

a circuit unit producing RGB reference voltages and scanning signal voltages using RGB data and control signals transmitted from an external driving system;

a liquid crystal display panel changing alignment direction of liquid crystal molecules in accordance with the RGB reference voltages and the scanning signal voltages; and

a backlight device emitting light to the liquid crystal display panel,

wherein the circuit unit includes;

an interface receiving the RGB data and the control signals from the external driving system;

a timing controller generating gate control signals and data control signals in accordance with the RGB data and the control signals;

at least two gamma generating units generating the RGB reference voltages having different values in accordance with the RGB data;

a switch selecting one of the RGB reference voltages;

a data driver receiving the data control signal from the timing controller and the selected RGB reference voltage selected from the switch, and supplying an RGB image voltage to the liquid crystal display panel in accordance with the selected RGB reference voltage and the data control signal; and

a gate driver receiving the gate control signals from the timing controller and supplying the scanning signal voltage to the liquid crystal display panel in accordance with the gate control signal.

2. The device according to claim 1, wherein the backlight device includes at least three light sources.

3. The device according to claim 2, wherein each of the three color light sources has one color of red, green, and blue.

4. The device according to claim 1, wherein the at least two gamma generating units sequentially generate an R reference voltage, a G reference voltage, and a B reference voltage in each frame such that each of the R, G, and B reference voltages have different values.

5. The device according to claim 4, wherein the switch selects one of the R, G, and B reference voltages in each sub-frame.

6. The device according to claim 5, wherein within one frame the data driver sequentially outputs an R image voltage in accordance with the R reference voltage selected by the switch, a G image voltage in accordance with the G reference voltage selected by the switch, and a B image voltage in accordance with the B reference voltage selected by the switch.

7. The device according to claim 6, wherein within each frame the gate driver simultaneously outputs an R scanning signal voltage corresponding to the R image voltage, a G scanning signal voltage corresponding to the G image voltage, and a B scanning voltage corresponding to the B image voltage.

8. The device according to claim 7, wherein within each frame the backlight device sequentially turns ON and OFF an R light source after supplying the R scanning signal voltage to the liquid crystal display panel, a G light source after supplying the G scanning signal voltage to the liquid crystal display panel, and a B light source after supplying the B scanning signal voltage to the liquid crystal display panel.

9. The device according to claim 8, wherein the gamma generating units include first and second generating units, and the B reference voltage of the second gamma generating unit produces a lowest transmissivity of blue color at a time when the R and G reference voltages of the first gamma generating unit produce a lowest transmissivity of red and green colors.

10. The device according to claim 9, wherein each frame lasts about {fraction (1/60)} of a second, and includes three sub-frames each lasting about {fraction (1/180)} of a second.

11. The device according to claim 10, wherein each sub-frame lasting about {fraction (1/180)} of a second includes supplying the R image voltage and the R scanning signal voltage, and then turning ON and OFF the R light source.

12. The device according to claim 10, wherein each sub-frame lasting about {fraction (1/180)} of a second includes supplying the G image voltage and the G scanning signal voltage, and then turning ON and OFF the G light source.

13. The device according to claim 10, wherein each sub-frame lasting about {fraction (1/180)} of a second includes applying the B image voltage and the B scanning signal voltage, and then turning ON and OFF the B light source.

14. The device according to claim 1, wherein the liquid crystal molecules include Optical Compensated Birefringent mode liquid crystals.

15. A method of fabricating a field sequential liquid crystal display device, comprising:

providing a circuit unit for producing RGB reference voltages and scanning signal voltages using RGB data and control signals transmitted from an external driving system;

providing a liquid crystal display panel for changing alignment direction of liquid crystal molecules in accordance with the RGB reference voltages and the scanning signal voltages; and

providing a backlight device for emitting light to the liquid crystal display panel,

wherein the circuit unit includes;

an interface receiving the RGB data and the control signals from the external driving system;

a timing controller generating gate control signals and data control signals in accordance with the RGB data and the control signals;

at least two gamma generating units generating the RGB reference voltages having different values in accordance with the RGB data;

a switch selecting one of the RGB reference voltages;

a data driver receiving the data control signal from the timing controller and the selected RGB reference voltage selected from the switch, and supplying an RGB image voltage to the liquid crystal display panel in accordance with the selected RGB reference voltage and the data control signal; and

a gate driver receiving the gate control signals from the timing controller and supplying the scanning signal voltage to the liquid crystal display panel in accordance with the gate control signal.

16. The method according to claim 15, wherein providing the backlight device includes providing at least three light sources.

17. The method according to claim 16, wherein each of the three color light sources has one color of red, green, and blue.

18. The method according to claim 15, wherein the at least two gamma generating units sequentially generate an R reference voltage, a G reference voltage, and a B reference voltage in each frame such that each of the R, G, and B reference voltages have different values.

19. The method according to claim 18, wherein the switch selects one of the R, G, and B reference voltages in each sub-frame.

20. The method according to claim 19, wherein within one frame the data driver sequentially outputs an R image voltage in accordance with the R reference voltage selected by the switch, a G image voltage in accordance with the G reference voltage selected by the switch, and a B image voltage in accordance with the B reference voltage selected by the switch.

21. The method according to claim 20, wherein within each frame the gate driver simultaneously outputs an R scanning signal voltage corresponding to the R image voltage, a G scanning signal voltage corresponding to the G image voltage, and a B scanning voltage corresponding to the B image voltage.

22. The method according to claim 21, wherein within each frame the backlight device sequentially turns ON and OFF a R light source after supplying the R scanning signal voltage to the liquid crystal display panel, a G light source after supplying the G scanning signal voltage to the liquid crystal display panel, and a B light source after supplying the B scanning signal voltage to the liquid crystal display panel.

23. The method according to claim 22, wherein the gamma generating units include first and second generating units, and the B reference voltage of the second gamma generating unit produces a lowest transmissivity of blue color at a time when the R and G reference voltages of the first gamma generating unit produce a lowest transmissivity of red and green colors.

24. The method according to claim 23, wherein each frame lasts about {fraction (1/60)} of a second, and includes three sub-frames each lasting about {fraction (1/180)} of a second.

25. The method according to claim 24, wherein each sub-frame lasting about {fraction (1/180)} of a second includes supplying the R image voltage and the R scanning signal voltage, and then turning ON and OFF the R light source.

26. The method according to claim 24, wherein each sub-frame lasting about {fraction (1/180)} of a second includes supplying the G image voltage and the G scanning signal voltage, and then turning ON and OFF the G light source.

27. The method according to claim 24, wherein each sub-frame lasting about {fraction (1/180)} of a second includes applying the B image voltage and the B scanning signal voltage, and then turning ON and OFF the B light source.

28. The method according to claim 15, wherein the liquid crystal molecules include Optical Compensated Birefringent mode liquid crystals.