DISPLAY APPARATUS AND METHOD OF DRIVING THE SAME

• US 20090021669A1
• Filed: 02/01/2008
• Published: 01/22/2009
• Est. Priority Date: 07/19/2007
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Jun-Woo, Kim, Hee-Seop, Lee, Seung-Hoon, Han, Eun-Hee
• Application Number:
  US12/024,644
• Publication Number:
  US 20090021669A1
• Time in Patent Office: Days
• US Class Current: 349/72
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2320/10 Special adaptations of display systems for operation with variable images
• CPC Class Codes: G09G 2330/12 Test circuits or failure detection circuits included in a display system, as permanent part thereof
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A display apparatus displays an image in a normal driving mode at a low temperature where a response speed of a liquid crystal becomes lower than a critical value, and displays the image in an impulsive driving mode at a higher temperature where the response speed of the liquid crystal becomes higher than the critical value.

Claims

1. A display apparatus, comprising:

a display panel to display an image;

a temperature detector to detect an ambient temperature and output a signal corresponding to the detected ambient temperature;

a comparator to compare the signal output from the temperature detector with a reference value and to output a control signal corresponding to the comparison result; and

a driving mode selector to select either a normal driving mode or an impulsive driving mode in response to the control signal.

2. The display apparatus of claim 1, wherein the signal is a first voltage, and the reference value is a second voltage

3. The display apparatus of claim 2, wherein the display panel comprises an optically compensated bend mode liquid crystal.

4. The display apparatus of claim 2, wherein the temperature detector comprises a thin film transistor arranged in a peripheral area of the display panel.

5. The display apparatus of claim 4, wherein the temperature detector further comprises a fixed resistance connected to a reference voltage, and

wherein the fixed resistance, a gate electrode of the thin film transistor, a source electrode of the thin film transistor, and an output terminal of the temperature detector are connected to each other at a first node, and a drain electrode of the thin film transistor is grounded.

6. The display apparatus of claim 4, wherein the voltage comparator outputs a first control signal when the first voltage output from the temperature detector is higher than the second voltage, and outputs a second control signal when the first voltage output from the temperature detector is lower than the second voltage.

7. The display apparatus of claim 6, wherein the driving mode selector selects the normal driving mode in response to the first control signal, and selects the impulsive driving mode in response to the second control signal.

8. The display apparatus of claim 4, wherein the temperature detector further comprises a fixed resistance,

wherein a source electrode of the thin film transistor is connected to a reference voltage,

wherein a drain electrode of the thin film transistor, a first terminal of the fixed resistance, and an output terminal of the temperature detector are connected to each other at a first node, and

wherein a second terminal of the fixed resistance is grounded.

9. The display apparatus of claim 8, wherein the voltage comparator outputs a first control signal when the first voltage output from the temperature detector is lower than the second voltage, and outputs a second control signal when the voltage output from the temperature detector is higher than the second voltage.

10. The display apparatus of claim 9, wherein the driving mode selector selects the normal driving mode in response to the first control signal, and selects the impulsive driving mode in response to the second control signal.

11. The display apparatus of claim 2, further comprising a driving voltage generator inside which the temperature detector is positioned,

wherein the temperature detector comprises:

a thermal switch that is closed at a temperature equal to or higher than a critical temperature and open at a temperature lower than the critical temperature; and

a diode that is connected in parallel with the thermal switch.

12. The display apparatus of claim 11, wherein the driving voltage generator outputs a third voltage at the temperature equal to or higher than the critical temperature, and outputs a fourth voltage at the temperature lower than the critical temperature.

13. The display apparatus of claim 12, wherein the voltage comparator outputs a first control signal in response to the third voltage, and outputs a second control signal in response to the fourth voltage.

14. The display apparatus of claim 13, wherein the driving mode selector selects the impulsive driving mode in response to the first control signal, and selects the normal driving mode in response to the second control signal.

15. A method of driving a display apparatus, comprising:

displaying an image;

detecting an ambient temperature;

outputting a signal corresponding to the ambient temperature;

comparing the signal with a reference value;

outputting a first control signal when the signal is higher than the reference value, and outputting a second control signal when the voltage is lower than the critical voltage; and

selecting either a normal driving mode or an impulsive driving mode in response to the first control signal or the second control signal.

16. The method of claim 15, wherein the signal is a first voltage, and the reference value is a second voltage.

17. The method of claim 16, wherein the display apparatus is operated in an optically compensated bend mode when displaying the image.

18. The method of claim 17, wherein the selecting of the driving mode comprises;

selecting the normal driving mode in response to the first control signal; and

selecting the impulsive driving mode in response to the second control signal.

19. The method of claim 15, wherein the selecting of the driving mode comprises;

selecting the impulsive driving mode in response to the first control signal; and

selecting the normal driving mode in response to the second control signal.