Liquid crystal display adaptive to viewing angle

• US 20020149575A1
• Filed: 02/19/2002
• Published: 10/17/2002
• Est. Priority Date: 02/19/2001
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Moon, Seung-Hwan
• Granted Patent: US 7,123,223 B2
• Time in Patent Office: Days
• US Class Current: 345/204
• 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) adaptive to a viewing angle, comprising:

a driving voltage generator for generating first and second voltages based on an externally input power;

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

a viewing angle generator for generating information about the viewing angle based on the second and third voltages; and

a gamma curve determiner for selecting a liquid crystal gamma curve corresponding to received information about the viewing angle, 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 a gate-on/off voltage, and the second voltage is an analog driving voltage.

3. The LCD as claimed in claim 1, wherein the voltage divider comprises a variable resistor for 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 the rotational axis of the variable resistor is connected to that of a hinge supporting an LCD module so as to automatically select the gamma curve by operation of a user.

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

6. An LCD adaptive to a viewing angle, comprising:

a driving voltage generator for generating first and second voltages based on an externally input power;

a decoder for decoding information of the viewing angle as received by operation of a user;

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

a viewing angle generator for generating information about the viewing angle based on the second and third voltages; and

a gamma curve determiner for selecting a liquid crystal gamma curve corresponding to received information about the viewing angle, 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 a gate-on voltage, and the second voltage is an analog driving voltage.

8. An LCD adaptive to a viewing angle, comprising:

a driving voltage generator for generating a first voltage based on an externally input power;

a decoder for decoding information of the viewing angle as received by operation of a user;

a power selector comprising a plurality of voltage sources, for selecting any one of the voltage sources based on the decoded information of the viewing angle to generate a second voltage;

a viewing angle generator for generating information about the viewing angle based on the first and second voltages; and

a gamma curve determiner for selecting a liquid crystal gamma curve corresponding to the received information about the viewing angle, 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. An LCD adaptive to a viewing angle, comprising:

a driving voltage generator for generating an analog driving voltage based on an input power externally received via a first input;

a viewing angle generator for generating information about the viewing angle with a level of the analog driving voltage dropped based on the viewing angle, and feeding the level-dropped analog driving voltage back to a second input of the driving voltage generator; and

a gamma curve determiner for selecting a liquid crystal gamma curve corresponding to the received information about the viewing angle, 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 generator comprises:

a first resistor receiving the analog driving voltage at one terminal thereof; and

a second resistor having one terminal connected to a reference voltage or ground, and another terminal connected to another terminal of the first resistor, for lowering a level of the analog driving voltage and feeding the level-dropped analog driving voltage back to the second input of the driving voltage generator.

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.

14. The notebook computer of claim 13, wherein the variable resistor is mounted on a hinge supporting the LCD panel, with the hinge having a rotational axis connected to that of the variable resistor.

18. The method of claim 17, wherein enhanced gray color representation is provided by said varying voltage application as a function of visual field angle, compared to not varying voltage application as a function of visual field angle.

13. A notebook computer comprising:

a variable resistor;

an LCD panel;

wherein the variable resistor varies voltage application to liquid crystals constituting the LCD panel, with voltage application being a function of visual field angle.

15. A method for LCD gamma curve correction, 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;

VCE is collector-emitter electrode voltage;

V_BE is a base-emitter electrode voltage;

R1 is a resistor; and

adjusting an LCD gamma curve based on the plot.

16. A method of reducing flicker for an 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;

VCE is collector-emitter electrode voltage;

V_BE is a base-emitter electrode voltage;

R1 is a resistor; and

adjusting the LCD gamma curve based on the plot.

17. A method of enhancing user visibility of a notebook computer comprising an LCD panel, comprising at least the steps of:

(a) varying voltage application to liquid crystals, wherein amount of voltage applied is a function of visual field angle.