Backlit display with improved dynamic range

• US 7,499,017 B2
• Filed: 03/08/2007
• Issued: 03/03/2009
• Est. Priority Date: 11/09/2001
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Daly, Scott J.
• Primary Examiner(s): Awad; Amr
• Assistant Examiner(s): Sherman; Stephen G
• Application Number:
  US11/715,318
• Publication Number:
  US 20070159450A1
• Time in Patent Office: 726 Days
• Field of Search: 345/102, 345/204, 345/87, 345/76, 345/82, 345/690, 349/61, 349/62
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/02 Improving the quality of display appearance
• CPC Class Codes: G09G 2320/0238 Improving the black level
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix

Abstract

A display is backlit by a source having spatially modulated luminance to attenuate illumination of dark areas of images and increase the dynamic range of the display.

Claims

1. A backlit display, comprising:

a backlight to output light at a controllable luminance level; and

a light valve to control, per pixel, transmittance of light from said backlight to create an image, said backlight comprising a plurality of light sources that are independently controllable, the light sources respectively corresponding to areas that constitute part of said image wherein luminance of said light source corresponding to each of said areas is controlled based upon a size of a dark area of said image to be displayed in each of said areas, wherein, for each of said areas, if the size of the dark area of said image to be displayed is relatively small compared to the size of the area, said luminance of a corresponding light source is not attenuated.

2. The backlit display as set forth in claim 1, wherein:

said backlight is usable to output light at a spatially modulatable luminance.

3. The backlit display as set forth in claim 1, wherein in accordance with a first feature regarding brightness of said image to be displayed in each of said areas, luminance of said light source corresponding to the each of said areas is controlled.

4. A backlit display, comprising:

a backlight to output light at a controllable luminance level; and

a light valve to control, per pixel, transmittance of light from said backlight to create an image,

said backlight comprising a plurality of light sources that are independently controllable, the light sources respectively corresponding to areas that constitute part of said image wherein luminance of said light source corresponding to each of said areas is controlled according to presence of a small bright component in a dark area of said image to be displayed in each of said areas, wherein, for each of said areas, if the dark area of said image to be displayed includes the presence of the small bright component, said luminance of a corresponding light source is not attenuated.

5. The backlit display as set forth in claim 4, wherein:

said backlight is usable to output light at a spatially modulatable luminance.

6. The backlit display as set forth in claim 4, wherein

the light sources are respectively provided in said areas that constitute part of said image.

7. A backlit display, comprising:

a backlight to output light at a controllable luminance level, said backlight including a plurality of light sources that are independently controllable; and

a light valve to control, per pixel, transmittance of light from said backlight to create an image, in accordance with a first feature regarding brightness of said image to be displayed in areas constituting part of the image, luminance of said light source corresponding to the each of said areas is controllable, and wherein luminance of said light source corresponding to each of said areas is controlled based upon a comparison between a maximum luminance of said image to be displayed in each of said areas and a threshold, wherein, for each of said areas, if the maximum luminance of said image to be displayed exceeds the threshold, said luminance of a corresponding light source is not attenuated.

8. The backlit display as set forth in claim 7, wherein:

said backlight is usable to output light at a spatially modulatable luminance.

9. The backlit display as set forth in claim 7, wherein

the light sources are respectively provided in said areas that constitute part of said image.

10. A backlit display, comprising:

a backlight to output light at a controllable luminance level; and

a light valve to control, per pixel, transmittance of light from said backlight to create an image, said backlight comprising a plurality of light sources that are independently controllable, the light sources respectively corresponding to areas that constitute part of said image wherein luminance of said light source is controlled based upon a size of a dark area of said image to be displayed in each of said areas, said luminance of said light source being controlled so that the human vision system is able to detect details in said dark areas, wherein, for each of said areas, said luminance of said corresponding light source is not attenuated upon the size of the dark area being relatively small compared to the size of the area.

11. The backlit display as set forth in claim 10, wherein:

said backlight is usable to output light at a spatially modulatable luminance.

12. The backlit display as set forth in claim 10, wherein in accordance with a first feature regarding brightness of said image to be displayed in each of said areas, luminance of said light source corresponding to the each of said areas is controlled.

13. A backlit display, comprising:

a backlight to output light at a controllable luminance level; and

a light valve to control, per pixel, transmittance of light from said backlight to create an image,

said backlight comprising a plurality of light sources that are independently controllable, the light sources respectively corresponding to areas that constitute part of said image wherein luminance of said light source is controlled according to the presence of a small bright component of a dark area of said image to be displayed in each of said areas, said luminance of said light source being controlled so that the human vision system is able to detect details in said dark areas, wherein, for each of said areas, said luminance of said corresponding light source is not attenuated upon the dark area of said image to be displayed including the small bright component.

14. The backlit display as set forth in claim 13, wherein:

said backlight is usable to output light at a spatially modulatable luminance.

15. The backlit display as set forth in claim 13, wherein

the light sources are respectively provided in said areas that constitute part of said image.

16. A backlit display, comprising:

a backlight to output light at a controllable luminance level, said backlight including a plurality of light sources that are independently controllable; and

a light valve to control, per pixel, transmittance of light from said backlight to create an image, in accordance with a first feature regarding brightness of said image to be displayed in areas constituting part of the image, luminance of said light source corresponding to the each of said areas is controllable, and wherein luminance of said light source is controlled based upon a comparison between a maximum luminance of said image to be displayed in each of said areas and a threshold, said luminance of said light source being controlled so that the human vision system is able to detect details in said areas, wherein, for each of said areas, said luminance of said light source is not attenuated upon the maximum luminance of said image to be displayed exceeding the threshold.

17. The backlit display as set forth in claim 16, wherein:

said backlight is usable to output light at a spatially modulatable luminance.

18. The backlit display as set forth in claim 16, wherein

the light sources are respectively provided in said areas that constitute part of said image.