LIGHT SENSOR WITHIN DISPLAY

• US 20080248837A1
• Filed: 05/10/2007
• Published: 10/09/2008
• Est. Priority Date: 04/05/2007
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Ericsson Mobile Communications AB (Sony Group Corp.)
• Inventors: Kunkel, Lars Peter
• Granted Patent: US 8,289,248 B2
• Time in Patent Office: Days
• US Class Current: 455/566
• CPC Class Codes: G09G 2320/062 Adjustment of illumination source parameters
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A mobile communication device with a display may be configured to apply pulse width modulation (PWM) signals to light emitting diodes (LEDs) for providing backlighting for the display, monitor ambient light conditions during off periods of PWM signals applied to the LEDs and adjust the PWM signals based the monitored ambient light conditions.

Claims

1. A method comprising:

providing backlighting to a display;

sensing ambient light conditions during off periods of the backlighting; and

adjusting a brightness of the backlighting based on the sensed ambient light conditions.

2. The method of claim 1, wherein adjusting the brightness of the backlighting further comprises:

adjusting the sensed ambient light conditions based on an image on the display.

3. The method of claim 2, wherein adjusting the brightness of the backlighting further comprises:

changing a duty cycle of a pulse width modulation (PWM) signal.

4. The method of claim 1, wherein the sensed ambient light conditions are sensed by light sensors, wherein the light sensors are located adjacent to backlighting LEDs.

5. The method of claim 4, wherein the light sensors and the backlighting LEDs are located adjacent to a light guide.

6. The method of claim 5, wherein the display is a liquid crystal display (LCD).

7. A mobile communication device comprising:

a display, the display including;

light emitting diodes (LEDs) for providing backlight,

light sensors for sensing light,

a liquid crystal display (LCD) for displaying images, and logic configured to;

apply pulse width modulation (PWM) signals to the LEDs,

monitor an intensity of light received from the light sensors during off periods of the PWM signals,

adjust the monitored intensity based on a currently displayed image, and

adjust the PWM signals based on the adjusted monitored intensity.

8. The mobile communication device of claim 7, wherein the light sensors are located adjacent to the LEDs.

9. The mobile communication device of claim 8, wherein the light sensors and the LEDs are located adjacent to a light guide.

10. The mobile communication device of claim 7, wherein the currently displayed image is produced by the LCD.

11. The mobile communication device of claim 7, wherein the adjusting the PWM signals based on the adjusted monitored intensity further comprises:

changing a duty cycle of the PWM signals.

12. The mobile communication device of claim 11, wherein the adjusting the PWM signals based on the adjusted monitored intensity further comprises:

changing the duty cycle of the PWM signals based on a stored value of the adjusted monitored intensity signal.

13. The mobile communication device of claim 10, wherein the light guide is located underneath the LCD.

14. A method comprising:

applying pulse width modulation (PWM) signals to light emitting diodes (LEDs) for providing backlighting for a display;

monitoring ambient light conditions during off periods of PWM signals applied to the LEDs; and

adjusting the PWM signals based the monitored ambient light conditions.

15. The method of claim 14, further comprising:

adjusting the monitored ambient light conditions with known lighting values.

16. The method of claim 15, wherein the adjusting the PWM signals based the monitored ambient light conditions further comprises:

changing a duty cycle of the PWM signal.

17. The method of claim 16, wherein the known light conditions are associated with an image on the display.

18. The method of claim 16, wherein the adjusting the PWM signals based the monitored ambient light conditions further comprises:

changing the duty cycle of the PWM signals based on a stored value of the adjusted monitored intensity signal.

19. The method of claim 14, wherein the ambient light conditions are monitored by a light sensor, wherein the light sensor is located adjacent to the LEDs.

20. The method of claim 19, wherein the light sensor and the LEDs are located adjacent to a light guide.