APPARATUS AND METHOD TO ENHANCE LEGIBILITY OF IMAGES SHOWN ON A DISPLAY

• US 20110310131A1
• Filed: 06/01/2011
• Published: 12/22/2011
• Est. Priority Date: 06/21/2010
• Status: Active Grant

• Current Assignee: Fergason Licensing LLC
• Original Assignee: Fergason Patent Properties
• Inventors: FERGASON, John D., FERGASON, James L.
• Granted Patent: US 9,218,770 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

A display system and method for improving legibility of images viewed on a passive display in a bright environment, including apparatus and method for increasing or maintaining the range of grey levels for the image as viewed on the display and decreasing the number of grey levels used in that range.

Claims

1-5. -5. (canceled)

6. A method of improving contrast of images that are provided by a passive display that is capable of modulating incident light over a range of grey levels in response to an image signal, comprising

reducing the number of grey levels at which the light is modulated and increasing the magnitude of brightness difference between respective pairs of adjacent grey levels in the range of grey levels.

7. The method of claim 6, wherein said reducing and increasing comprises reducing the number of grey levels while substantially maintaining the range of grey levels.

8. The method of claim 6, wherein said reducing grey levels comprises combining at least two grey levels.

10. The method of claim 6, wherein said reducing grey levels comprise combining a first pair of grey levels that are relatively adjacent in brightness levels of light provided after modulation by the passive display to obtain one grey level, and combining a second pair of grey levels that are relatively adjacent in brightness levels of light provided after modulation by the passive display to obtain a second grey level different from the one grey level.

12. The method of claim 6, comprising simultaneously illuminating the passive display with light of different colors from respective light sources.

13. The method of claim 12, wherein said illuminating comprises illuminating the passive display with light of colors that combine to illuminate the display with substantially white light.

16. The method of claim 6, said reducing the number of grey levels comprising reducing the number of grey levels to two grey levels, respectively, at or near the ends of the range of grey levels.

9. (canceled)

11. (canceled)

14-15. -15. (canceled)

17. A display device for displaying an image represented by an input image signal having a first number of grey levels, the display device comprising:

a liquid crystal display panel;

a backlight; and

a control operatively coupled to the liquid crystal display panel and the backlight, wherein the control is configured to receive the input image signal including a number of grey levels and data indicative of ambient brightness, and, if the ambient brightness is above a predetermined threshold, the control is configured to adjust intensity of the backlight while adjusting transmission of the liquid crystal display panel to reduce the first number of grey levels to a second number of grey levels.

18. The display device of claim 17, further comprising:

a brightness detection unit configured to detect brightness of ambient light and provide data indicative of ambient brightness to the control.

19. The display device of claim 17, wherein the control is configured to adjust the intensity of the backlight by reducing the intensity of the backlight.

20. The display device of claim 17, wherein the input image signal includes a first number of grey levels within a given range, and the control is configured to reduce the number of grey levels while maintaining the given range of grey levels.

21. A method of displaying an image on a display apparatus in a bright ambient environment, the display apparatus including a backlight, a passive display panel and a control, the image being represented by an input image signal having a first number of grey levels, the method comprising:

adjusting intensity of the backlight while adjusting transmission of the passive display panel to reduce the first number of grey levels to a second number of grey levels; and

displaying the image using the adjusted backlight intensity and the modified number of grey levels.

22-28. -28. (canceled)

29. A method of operating a field sequential multicolor display, comprising

converting a signal representing a multicolor image to a signal representing a monochrome image, and

illuminating the display simultaneously with light of different colors.

30. The method of claim 29, said converting comprising converting respective images representing respective color components of a multicolor image for presentation in sequential fields by the display to a monochromatic image.

31. A method of increasing legibility of a color sequential display system that is operable to provide multicolor images and includes a display to present an image and sources of light of different respective colors to illuminate the display, comprising

converting a multicolor image into a monochromatic image for presenting on the display, and

illuminating the display simultaneously with light of different colors from a plurality of the sources of light.

32. A method of displaying an image on a passive display in an environment in which there is ambient light, wherein the passive display has a capability of modulating light from a display light source over a predetermined range of grey shade levels to provide a range and number of grey shade levels seen by a viewer of the passive display, comprising when the intensity of ambient light incident on the passive display is increased

reducing the intensity of light incident on the passive display by the display light source,

maintaining a relatively wide range and relatively reduced number of grey shade levels provided by the passive display as illuminated by the display light source thereby to provide a relatively wide range of grey levels seen by a viewer of the passive display, and

reducing the number of grey shade levels seen by the viewer.

33. A display system, comprising

a display light source,

a passive display capable of modulating incident light from the display light source over a range of grey shade levels to provide grey shade levels in forming an image for viewing by a viewer,

a controller operable to improve legibility of the image when the intensity of ambient light incident on the passive display is increased by reducing intensity of incident light from the display light source while maintaining a relatively wide range and reduced number of grey shade levels forming an image for viewing by a viewer.

34. A method of displaying images provided by an LCD capable of operation in color sequential mode using a plurality of light sources of different colors, comprising

concurrently illuminating the LCD by a plurality of light sources of different colors while combining as one image images represented by the colors of said plurality of light sources of different colors.

35. The method of claim 34, said concurrently illuminating comprising illuminating the LCD using red, green and blue light.

36. The method of claim 34, said concurrently illuminating comprising illuminating the LCD with a combination of light of different colors that combine to provide illumination by white light.

37. (canceled)