Optical display system and method, active and passive dithering using birefringence, color image superpositioning and display enhancement with phase coordinated polarization switching

• US 6,816,141 B1
• Filed: 10/02/2000
• Issued: 11/09/2004
• Est. Priority Date: 10/25/1994
• Status: Expired due to Fees

• Current Assignee: Fergason Patent Properties
• Original Assignee: Fergason Patent Properties
• Inventors: Fergason, James L.
• Primary Examiner(s): Liang, Regina
• Application Number:
  US09/676,915
• Time in Patent Office: 1,499 Days
• Field of Search: 345/88, 345/87, 345/204, 345/102, 345/55, 345/690-697, 348/673, 315/169.3, 349/61-67
• US Class Current: 345/88
• CPC Class Codes: G02B 2027/0112 comprising device for genereting colour display
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: G02B 5/30 Polarising elements light-modulating devices with active elements G02F1/00
• CPC Class Codes: G02B 5/3083 Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001
• CPC Class Codes: G02F 1/133562 on the viewer side
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n
• CPC Class Codes: G02F 1/1347 Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
• CPC Class Codes: G02F 2203/62 Switchable arrangements whereby the element being usually not switchable
• CPC Class Codes: G02F 2413/04 Number of plates greater than or equal to 4
• CPC Class Codes: G02F 2413/08 with a particular optical axis orientation
• CPC Class Codes: G09G 2310/0224 Details of interlacing
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2310/0237 Switching ON and OFF the backlight within one frame
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• 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 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• 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 2330/021 : Power management, e.g. power saving
• CPC Class Codes: G09G 2340/0407 : Resolution change, inclusive of the use of different resolutions for different screen areas
• 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 3/002 : to project the image of a two-dimensional display, such as an array of light emitting or modulating elements or a CRT
• CPC Class Codes: G09G 3/007 : Use of pixel shift techniques, e.g. by mechanical shift of the physical pixels or by optical shift of the perceived pixels
• CPC Class Codes: G09G 3/2007 : Display of intermediate tones
• CPC Class Codes: G09G 3/2044 : using dithering
• CPC Class Codes: G09G 3/2051 : with use of a spatial dither pattern
• CPC Class Codes: G09G 3/2055 : the pattern being varied in time
• CPC Class Codes: G09G 3/3406 : Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3413 : Details of control of colour illumination sources
• CPC Class Codes: G09G 3/36 : using liquid crystals
• CPC Class Codes: G09G 3/3611 : Control of matrices with row and column drivers
• CPC Class Codes: G09G 3/3648 : using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: H01J 2229/8926 : Active components, e.g. LCD's, indicators, illuminators and moving devices
• CPC Class Codes: H01J 2329/897 : Lenses
• CPC Class Codes: H01J 29/89 : Optical or photographic arrangements structurally combined or co-operating with the vessel H01J29/866 and H01J29/868 take precedence
• CPC Class Codes: H04N 13/305 : using lenticular lenses, e.g. arrangements of cylindrical lenses
• CPC Class Codes: H04N 13/31 : using parallax barriers
• CPC Class Codes: H04N 13/324 : Colour aspects
• CPC Class Codes: H04N 13/341 : using temporal multiplexing
• CPC Class Codes: H04N 13/344 : with head-mounted left-right displays
• CPC Class Codes: H04N 13/395 : with depth sampling, i.e. the volume being constructed from a stack or sequence of 2D image planes
• CPC Class Codes: H04N 13/398 : Synchronisation thereof; Control thereof
• CPC Class Codes: H04N 5/66 : Transforming electric information into light information scanning details H04N3/00
• CPC Class Codes: H04N 5/7441 : the modulator being an array of liquid crystal cells
• CPC Class Codes: H04N 5/7491 : of head mounted projectors
• CPC Class Codes: H04N 9/16 : using cathode ray tubes H04N9/11 takes precedence
• CPC Class Codes: H04N 9/30 : using solid-state colour display devices
• CPC Class Codes: H04N 9/3102 : using two-dimensional electronic spatial light modulators micromechanical modulators as such G02B26/0833; liquid crystal modulators as such G02F1/13
• CPC Class Codes: H04N 9/3155 : for controlling the light source light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406
• CPC Class Codes: H04N 9/3167 : for polarizing the light beam polarizing optical systems per se G02B27/28
• CPC Class Codes: H04N 9/3173 : wherein the projection device is specially adapted for enhanced portability
• CPC Class Codes: H04N 9/3188 : Scale or resolution adjustment scaling in general G06T3/40; resolution modifying circuits for displays in general G09G5/391

Abstract

A display apparatus includes a passive display, a light source, and a video signal input, in operation in response to a video signal the passive display modulates light from the light source to provide an image, and the intensity of the light source is controlled by the video signal.

A method of producing a displayed image using a passive display illuminated by a light source is characterized in controlling the light source to obtain a displayed image with a desired amount of information, gray scale and/or color characteristics.

A method of reducing power consumption by a display system in which a light modulating display modulates incident light from a light source to provide images is characterized in controlling power provided to the light source to reduce output thereof for relatively dark images.

Claims

1. A display apparatus, comprising a passive display, a light source, and a video signal input, wherein in response to a video signal the passive display modulates light from the light source to provide an image, and characterized in that the intensity of the light source being controlled by pixel information content of the video signal.

2. The apparatus of claim 1, further characterized in that the passive display is a projection display, and said projection display includes projection optics.

3. The apparatus of claim 1, further characterized in that the passive display is a direct view display, and comprising optics to provide the image for viewing from the direct view display.

46. The apparatus of claim 1, further characterized in that the passive display is a direct view display.

4. A display apparatus in which light from a light source illuminates a display to provide an image, characterized in that

the intensity of the light illuminating the display is controlled to adjust image brightness, and further characterized in that a computer control responds to the brightness information for the displayed image and controls the light source output without having to change the number of pixels used to transmit light to obtain images of respective brightness and/or color.

5. A method of improving dynamic range and/or definition of a passive display operable in response to a video signal in combination with an illuminating light source to display an image, the illuminating light source being capable of modulation, comprising sampling the video signal for image brightness information based on pixel information content;

adjusting the video signal for optimum definition and contrast; and

adjusting the intensity of the illuminating light source for optimum brightness all in synchronization with the display.

6. The method of claim 5, characterized in that said adjusting the intensity comprises adjusting the intensity of the light source to correspond with image brightness characteristics, and said adjusting the video signal comprises reducing the reliance on the operation of the display to alter image brightness characteristics.

7. The method of claim 5, characterized in that said sampling comprises computing image brightness of at least a portion of an image represented by such video signal.

8. The method of claim 5, wherein the display is a liquid crystal display, and further characterized in that the adjusted video signal is provided to the liquid crystal display to affect light transmission or reflection characteristics of respective picture elements (pixels) of the liquid crystal display.

9. The method of claim 5, wherein the passive display is a transmissive liquid crystal display, and further characterized in comprising directing input light through the passive display to display an image.

10. A display system including a display for modulating light from an illuminating source in response to a signal to provide a displayed image, the illuminating source being capable of modulation, comprising means for sampling the signal for image brightness information based on pixel information content, means for modifying the signal to optimize contrast and definition in the image, and means for adjusting the illuminating source to set the brightness of the display in synchronization with the presentation of the image.

11. The display system of claim 10, further characterized In that the optimization is carried out within the limitations of the display system.

12. The display system of claim 10, further characterized in that said signal is a video signal including image brightness information.

13. The display system of claim 10, further characterized in that said means for adjusting comprises means for adjusting the intensity of the light source to correspond with image brightness characteristics, and said means for modifying the signal comprises means for altering image brightness characteristics in synchronism with the displayed image to reduce the reliance on the operation of the display for displayed image brightness adjustment.

14. A display system comprising a display for modulating light from an illuminating source in response to a signal to provide a displayed image, wherein the illuminating source is capable of modulation, a sampling device sampling the signal for image brightness information based on pixel information content, a circuit modifying the signal to optimize contrast and definition in the image, and adjusting device operable to adjust the illuminating source to set the brightness of the display in synchronization with the presentation of the image.

15. A display system comprising a display for modulating illuminating light from an illuminating source in response to an input signal having pixel information content to provide a displayed image, wherein the illuminating source is capable of independently modulating both color and intensity, and further comprising means for changing the color and intensity of the illuminating light;

and means for sampling and modifying the input signal to optimize the color, resolution and contrast of the presented image simultaneously with changing the light source color and intensity.

16. The display system of claim 15, further characterized in that said means for sampling and modifying is operable to modify the input signal in synchronized relation with the changing the light source color and intensity.

17. The display system of claim 15, further characterized in that the illuminating light from the illuminating source has red, green and blue components.

18. The display system of claim 15, further characterized in that the illuminating source is operable to modulate the intensity of the red, green and blue color components of illuminating light.

19. The display system of claim 15, further characterized in that said signal is a video signal including image brightness information.

20. The display system of claim 15, further characterized in that said means for modifying comprises means for adjusting the intensity of the light source to correspond with image brightness characteristics, and said means for modifying the signal comprises means for altering image brightness characteristics in synchronism with the displayed image to reduce reliance on the operation of the display for displayed image brightness adjustment.

21. A display system comprising a display for modulating illuminating light from an illuminating source in response to an input signal having pixel information content to provide a displayed image, wherein the illuminating source is capable of independently modulating both color and intensity, and further comprising a control to change the color and intensity of the illuminating light;

and sampling and modifying circuitry to sample and modify the input signal to optimize the color, resolution and contrast of the presented image simultaneously with changing the light source color and intensity.

22. A method of displaying video images to improve dynamic range of both gray scale and color, wherein a display modulates input light from a light source capable of independently controlling intensity of color components of light to provide displayed images, characterized in

sensing the relative intensity of the red, green and blue components of the an input signal;

optimizing the video signal for each color for contrast and/or resolution; and

adjusting the light source for color and intensity based on the input signal to recover the original relative brightness of the image;

said sensing, optimizing and adjusting being all in synchronization with the displayed video images.

23. The method of claim 22, further characterized in that said adjusting the light source is carried out independently for different respective red, green and blue colors at video rates.

24. The method of claim 22, wherein the light source is comprised of respective light emitting diodes, and further characterized in that said adjusting the light source comprises independently adjusting respective diodes.

25. A method of improving dynamic range and/or resolution of a passive display operable in response to a video signal in combination with an illuminating light source to display an image, the illuminating light source being capable of modulation, characterized in sampling the video signal for image brightness information;

adjusting the video signal for improved resolution and contrast; and

adjusting the intensity of the illuminating light source based on pixel information content for improved brightness all in synchronization with the display.

26. The method of claim 25, characterized in that said adjusting the intensity comprises adjusting the intensity of the light source to correspond with image brightness characteristics, and said adjusting the video signal comprises reducing the reliance on the operation of the display to alter image brightness characteristics.

27. The method of claim 25, characterized in that said sampling comprises computing image brightness of at least a portion of an image represented by such video signal.

28. The method of claim 25, wherein the display is a liquid crystal display, and further characterized in that the adjusted video signal is provided to the liquid crystal display to affect light transmission or reflection characteristics of respective picture elements (pixels) of the liquid crystal display.

29. The method of claim 25, wherein the passive display is a transmissive liquid crystal display, and further characterized in comprising directing Input light through the passive display to display an image.

30. The method of claim 25, wherein the display modulates input light from the light source that is capable of dependently controlling intensity of color components of light to provide displayed images, further characterized in

computing brightness information of an image or scene from the input signal pertaining to the image or scene;

and

adjusting the light source for color and intensity to recover the original relative brightness of the image;

said computing and adjusting being all in synchronization with the displayed video images.

31. The method of claim 30, further characterized in comprising optimizing the video signal for each color for contrast and/or resolution.

32. The method of claim 30, further characterized in that said adjusting the light source is carried out independently for different respective red, green and blue colors at video rates.

33. The method of claim 30, wherein the light source is comprised of respective light emitting diodes, and further characterized in that said adjusting the light source comprises independently adjusting respective diodes.

34. A display system including a display for modulating light from an illuminating source in response to a signal to provide a displayed image, the illuminating source being capable of modulation, characterized in comprising means for sampling the signal for image brightness information, means for modifying the signal to improve contrast and resolution in the image, and means for adjusting the illuminating source based on pixel information content to set the brightness of the display in synchronization with the presentation of the image.

35. The display system of claim 34, further characterized in that the improving is carried out within the limitations of the display system.

36. The display system of claim 34, further characterized in that said signal is a video signal including image brightness information.

37. The display system of claim 34, further characterized in that said means for adjusting comprises means for adjusting the intensity of the light source to correspond with image brightness characteristics, and said means for modifying the signal comprises means for altering image brightness characteristics in synchronism with the displayed image to reduce the reliance on the operation of the display for displayed image brightness adjustment.

38. The display system of claim 34, wherein the illuminating source is capable of independently modulating both color and intensity, characterized in that said means for adjusting comprises means for changing the color and intensity of the illuminating light;

and further characterized in that said means for sampling comprises means for sampling and modifying the input signal to tend to optimize the color, resolution and contrast of the presented image simultaneously with changing the light source color and intensity.

39. The display system of claim 38, further characterized in that said means for sampling and modifying is operable to modify the input signal in synchronized relation with the changing the light source color and intensity.

40. The display system of claim 38, further characterized in that the illuminating light from the illuminating source has red, green and blue components.

41. The display system of claim 38, further characterized in that the illuminating source is operable to modulate the intensity of the red, green and blue color components of illuminating light.

42. The display system of claim 38, further characterized in that said signal is a video signal including image brightness information.

43. The display system of claim 38, further characterized in that said means for adjusting comprises means for adjusting the intensity of the light source to correspond with image brightness characteristics, and said means for modifying the signal comprises means for altering image brightness characteristics in synchronism with the displayed image to reduce reliance on the operation of the display for displayed image brightness adjustment.

44. A display apparatus in which light from a light source illuminates a display to provide an image, characterized in that

the intensity of the light illuminating the display is controlled to adjust image brightness, and further characterized in that a computer control responds to the brightness information for the displayed image and controls the light source output without having to change the number of pixels used to transmit light to obtain images of respective brightness.

45. The display apparatus of claim 44, wherein the computer control controls the light source output to obtain images of respective colors.