Liquid crystal display adaptive to viewing angle

• US 7,123,223 B2
• Filed: 02/19/2002
• Issued: 10/17/2006
• Est. Priority Date: 02/19/2001
• Status: Expired due to Fees

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Moon, Seung-Hwan
• Primary Examiner(s): LAO, LUN YI
• Application Number:
  US10/077,055
• Publication Number:
  US 20020149575A1
• Time in Patent Office: 1,701 Days
• Field of Search: 345 87-104, 345/204, 345/207, 345/690, 345/901, 345/905, 348/674
• US Class Current: 345/89
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2320/028 by changing the viewing angle properties, e.g. widening the viewing angle, adapting the viewing angle to the view direction
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers
• CPC Class Codes: Y10S 345/905 Display device with housing structure

Abstract

Disclosed is an LCD capable of adaptively selecting a gamma curve based on a viewing angle. The LCD includes: a viewing angle detector for detecting the viewing angle of an LCD panel to generate information about the viewing angle, and a gamma curve determiner for selecting a gamma curve corresponding to the information of the viewing angle and controlling the gray level with a gamma voltage value defined by the selected gamma curve. The viewing angle detector has a driving voltage generator and a voltage divider. The driving voltage generator outputs a gate-on/off voltage and an analog driving voltage based on an externally input power, and the voltage divider drops the level of the gate-on voltage to generate a first voltage. A viewing angle generator outputs information about the viewing angle based on the analog driving voltage and the first voltage.

Claims

1. A liquid crystal display (LCD), comprising:

a driving voltage generator receiving an input voltage and generating a first voltage and a second voltage;

a voltage divider converting a level of the second voltage based on a viewing angle of an LCD panel to generate a third voltage;

a viewing angle information generator receiving the first voltage and the third voltage and generating viewing angle information; and

a gamma curve determiner selecting a liquid crystal gamma curve corresponding to the viewing angle information and controlling a gray level with a gamma voltage value based on the selected liquid crystal gamma curve.

2. The LCD as claimed in claim 1, wherein the first voltage is an analog driving voltage and the second voltage is a gate-on voltage.

3. The LCD as claimed in claim 1, wherein the voltage divider comprises a variable resistor variably generating a resistance value based on the viewing angle of the LCD panel, and outputs the third voltage using the variable resistor.

4. The LCD as claimed in claim 3, wherein a rotational axis of the variable resistor is connected to a hinge supporting an LCD module.

5. The LCD as claimed in claim 4, wherein the variable resistor is a dial type or a sliding type.

6. A liquid crystal display (LCD), comprising:

a driving voltage generator receiving an input voltage and generating a first voltage and a second voltage;

a decoder for decoding viewing angle data from a user;

a voltage divider comprising a plurality of resistors, selecting one of the resistors based on the decoded viewing angle data and converting a level of the second voltage based on the selected resistor to generate a third voltage;

a viewing angle information generator generating viewing angle information based on the first voltage and third voltage; and

a gamma curve determiner selecting a liquid crystal gamma curve corresponding to the viewing angle information and controlling a gray level with a gamma voltage value based on the selected liquid crystal gamma curve.

7. The LCD as claimed in claim 6, wherein the first voltage is an analog driving voltage and the second voltage is a gate-on voltage.

8. A liquid crystal display (LCD), comprising:

a driving voltage generator receiving an input voltage and generating a first voltage;

a decoder decoding viewing angle data from a user;

a power selector comprising a plurality of voltage sources and selecting one of the voltage sources based on the decoded the viewing angle data to generate a second voltage;

a viewing angle information generator generating viewing angle information based on the first voltage and second voltage; and

a gamma curve determiner selecting a liquid crystal gamma curve corresponding to the viewing angle information and controlling a gray level with a gamma voltage value based on the selected liquid crystal gamma curve.

9. The LCD as claimed in claim 8, wherein the first voltage is an analog driving voltage.

10. A liquid crystal display (LCD), comprising:

a driving voltage generator receiving an input voltage via a first input terminal and generating an analog driving voltage;

a viewing angle information generator generating viewing angle information by lowering a level of the analog driving voltage based on a viewing angle and feeding the analog driving voltage having the lowered level back to a second input terminal of the driving voltage generator; and

a gamma curve determiner selecting a liquid crystal gamma curve corresponding to the viewing angle information and controlling a gray level with a gamma voltage value based on the selected liquid crystal gamma curve.

11. The LCD as claimed in claim 10, wherein the viewing angle information generator comprises:

a first resistor having a first terminal receiving the analog driving voltage; and

a second resistor having a first terminal connected to a reference voltage or ground and a second terminal connected to a second terminal of the first resistor, to lower the level of the analog driving voltage.

12. The LCD as claimed in claim 11, wherein either the first resistor or a reference voltage is varied depending on the viewing angle of an LCD panel.

13. A method for liquid crystal display (LCD) gamma curve correction, comprising steps of:

plotting a plot of [(AVDD−

V_CE+V_BE)/(Von−

AVDD+V_CE−

V_BE)]×

R1, wherein AVDD is a first voltage generated as an analog driving voltage, V_CE is a collector-emitter electrode voltage, VBE is a base-emitter electrode voltage and R1 is a resistor; and

adjusting an LCD gamma curve based on the plot.

14. A method of reducing flicker for a liquid crystal display (LCD) having a gamma curve, comprising the steps of:

plotting a plot of [(AVDD−

V_CE+V_BE)/(Von−

AVDD+V_CE−

V_BE)]×

R1, wherein AVDD is a first voltage generated as an analog driving voltage, V_CE is collector-emitter electrode voltage, V_BE is a base-emitter electrode voltage and R1 is a resistor; and

adjusting the LCD gamma curve based on the plot.