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

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.

1 - 88 . (canceled) 
     
     
         89 . A display device for displaying an image having a low intended brightness, the display device comprising:
 a display;   an illuminating light source;   a computer control, wherein the computer control:   receives brightness information, and determines brightness and a range of grey levels for the input image signal, and   if an image corresponding to the input image signal is a dim image of a low intended brightnes and low contrast, increases the range of grey levels used to display the image on the display corresponding to the input image signal, and decreases an amount of light from the illuminating light source so as to alleviate any decrease of brightness of the image which is caused by said increasing of the range of grey levels performed such that the low intended brightness of the image is preserved.   
     
     
         90 . A display device for displaying an image having a low intended brightness and an intended color balance, comprising:
 a display capable of displaying an image within a predetermined range of gray levels;   an illuminating light source capable of producing at least three different colors; and   a computer control arranged for receiving an input image signal, said image signal including color grey level information of an image relating to the at least three different colors and a brightness information of said image;   wherein the computer control:   receives said brightness information and said color grey level information, and determines a range of color grey levels for the input image signal;   changes the determined range of color grey levels to a second range of color grey levels which is larger than said determined range of color grey levels, if the brightness of said input image signal represents a dim image of low brightness low contrast;   and   decreases an amount of light from the illuminating light source if the brightness of the input image signal represents said dim image, so as to reduce increase of brightness of the image which is produced as a result of said change of the range of color gray levels into said second range of color gray levels, such that the low intended brightness and the intended color balance of the image is preserved.   
     
     
         91 . A display device for displaying an image having a high intended brightness or a low intended brightness and an intended color balance, comprising:
 a display capable of displaying an image within a predetermined range of grey levels;   an illuminating light source capable of producing at least three different least colors; and   a computer control arranged for receiving an input image signal, said image signal including color grey level information and the brightness information of said image by color component;   wherein the computer control:   receives said brightness information and said color grey level information, and determines a range of gray levels for the input image signal;   changes the determined range of grey levels to a second range of gray levels which is larger than said determined range of grey levels, if the brightness of said input image signal represents a high brightness image of high intended brightness with low contrast or a dim image of low intended brightness with low contrast;   increases an amount of light from the illuminating light source if the brightness of the input image signal represents said high brightness image, so as to reduce decrease of brightness of the image which is produced as a result of said change of the range of gray levels into said second gray levels such that the high intended brightness of the image is preserved and the intended color balance of the at least three different colors is preserved; and   decreases an amount of light from the illuminating light source if the brightness of the input image signal represents said dim image, so as to reduce the increase of brightness of the image which is produced as a result of said change of the range of gray levels into said second gray levels such that the low intended brightness of the image is preserved and the intended color balance among the three different colors is preserved.   
     
     
         92 . A method of controlling contrast of an image having a low intended brightness displayed by a display apparatus capable of displaying an image within a predetermined range of grey levels, the display apparatus including an illuminating light source and a computer control, the method comprising:
 processing brightness information of an input image signal and determining brightness and a range of grey levels for the input image signal; and   if the image corresponding to the input image signal is a dim image of a low brightness and low contrast, changing the determined range of grey levels to a second range of grey levels greater than the determined range of grey levels; and decreasing the amount of light from the illuminating light source so as to alleviate any increase of brightness of the image which is caused by performing the control of changing the range of grey levels to the second range of grey levels, such that the low intended brightness of the image is preserved.   
     
     
         93 . A method of controlling contrast of an image displayed by a display apparatus capable of performing color display within a predetermined range of grey levels, the display apparatus including an illuminating light source and a computer control, the method comprising:
 processing brightness information of an input image signal to determine a range of grey levels for an image corresponding to said input image signal and to determine whether the image corresponding to the input image signal is a bright image of a high brightness and low contrast or a dim image of a low brightness and low contrast; and   controlling contrast by;   increasing the determined range of grey levels toward a darker side if the image corresponding to the input image signal is a bright image of a high brightness and low contrast,   increasing the determined range of grey levels toward a brighter side if the image corresponding to the input image signal is a dim image of a low brightness and low contrast; and   adjusting the amount of light from the illuminating light source by increasing the amount of light from the illuminating light source, if the input signal corresponds to a bright image, and decreasing the amount of light from the illuminating light source, if the input signal corresponds to a dim image.   
     
     
         94 . A method of controlling contrast of an image displayed by a display apparatus capable of displaying an image within a predetermined range of grey levels, the display apparatus including an illuminating light source and a computer control, the method comprising:
 processing brightness information of an input image signal and determining brightness and a range of grey levels for the input image signal to determine if the image corresponding to the input image signal is a dim image of a low brightness and low contrast; and   if the image corresponding to the input image signal is a dim image of a low brightness and low contrast, changing the determined range of grey levels to a second range of grey levels which is expanded greater than said determined range of grey levels toward a brighter side, and decreasing the amount of light from the illuminating light source.   
     
     
         95 . A display device for displaying an image, comprising:
 a display capable of displaying an image within a predetermined range of grey levels;   an illuminating light source;   a computer control, wherein the computer control:   receives brightness information, and determines brightness and a range of grey levels for the input image signal to determine if the image corresponding to the input image signal is a dim image of a low brightness and low contrast, and   if an image corresponding to the input image signal is a dim image of a low brightness and low contrast, increases the range of grey levels used to display the image on the display corresponding to the input image signal to have the range of grey levels expanded greater than the determined range of grey levels toward a brighter side, and decreases an amount of light from the illuminating light source.   
     
     
         96 . A method of controlling contrast of a display image of a display apparatus including an illuminating light source, the method comprising:
 processing pixel information and determining a range of gray levels used for an input signal; and   adjusting an amount of light from the illuminating light source and changing the range of gray levels used to display an image corresponding to the input signal.   
     
     
         97 . The method of  claim 96 , wherein the pixel information includes brightness information. 
     
     
         98 . The method of  claim 96 , wherein the pixel information includes color information. 
     
     
         99 . The method of  claim 96 , wherein changing the range includes increasing the range. 
     
     
         100 . The method of  claim 96 , wherein adjusting the amount of light from the illuminating light source includes decreasing the amount of light if the image corresponding to the input signal is a dim image. 
     
     
         101 . The method of  claim 96 , wherein adjusting the amount of light from the illumination light source includes increasing the amount of light if the image corresponding to the input signal is a bright image. 
     
     
         102 . The method of  claim 96 , wherein adjusting the amount of light from the illuminating light source includes decreasing the amount of light if the image corresponding to the input signal has a brightness below a predetermined level. 
     
     
         103 . The method of  claim 96 , wherein adjusting the amount of light from the illuminating light source includes increasing the amount of light if the image corresponding to the input signal has a brightness above a predetermined level. 
     
     
         104 . The method of  claim 96 , wherein the illuminating light source emits a plurality of colors, the plurality of colors including at least one of red, green or blue. 
     
     
         105 . The method of  claim 96 , wherein the illuminating light source includes multiple a number of light emitting diodes emitting a plurality of colors. 
     
     
         106 . The method of  claim 105 , wherein the light emitting diodes provide light combinable to provide white light. 
     
     
         107 . The method of  claim 96 , further comprising measuring brightness of ambient environment of the display and further adjusting the amount of light from the illuminating light source and changing the range of the gray levels based on the brightness of the ambient environment. 
     
     
         108 . A method of controlling contrast of a display image of a display including an illuminating light source having a plurality of color components, the method comprising:
 processing pixel brightness and color information and determining a range of gray levels by color used for an input signal; and   adjusting an amount of light from the color components.   
     
     
         109 . The method of  claim 108 , further comprising changing the range of gray levels for the color components used to display an image corresponding to the input signal. 
     
     
         110 . The method of  claim 109 , wherein changing the range of gray levels is synchronous with the adjusting the amount of light from the color components. 
     
     
         111 . The method of  claim 108 , wherein the illuminating light source includes a plurality of light sources of different colors. 
     
     
         112 . The method of  claim 108 , wherein the illuminating light sources includes light emitting diodes of different colors. 
     
     
         113 . A display device for displaying an image, comprising:
 a display;   an illuminating light source;   a processor for receiving an input signal including pixel information and for determining a range of gray levels used for the input signal and for adjusting a range of the gray levels used to display an image on the display corresponding to the input signal.   
     
     
         114 . The device of  claim 113 , wherein the pixel information includes brightness information. 
     
     
         115 . The device of  claim 113 , wherein the pixel information includes color information. 
     
     
         116 . The device of  claim 113 , wherein changing the range includes increasing the range. 
     
     
         117 . The device of  claim 113 , wherein adjusting the amount of light from the illuminating light source includes decreasing the amount of light if the image corresponding to the input signal is a dim image. 
     
     
         118 . The device of  claim 113 , wherein adjusting the amount of light from the illumination light source includes increasing the amount of light if the image corresponding to the input signal is a bright image. 
     
     
         119 . The device of  claim 113 , wherein adjusting the amount of light from the illuminating light source includes decreasing the amount of light if the image corresponding to the input signal has a brightness below a predetermined level. 
     
     
         120 . The device of  claim 113 , wherein adjusting the amount of light from the illuminating light source includes increasing the amount of light if the image corresponding to the input signal has a brightness above a predetermined level. 
     
     
         121 . The device of  claim 113 , wherein the illuminating light source emits a plurality of colors, the plurality of colors including at least one of red, green or blue. 
     
     
         122 . The device of  claim 113 , wherein the illuminating light source includes a number of different color light emitting diodes. 
     
     
         123 . The device of  claim 122 , wherein the light emitting diodes provide light combinable to provide white light. 
     
     
         124 . The device of  claim 123 , wherein the light source includes a plurality of light emitting diodes that provide light combinable to provide white light. 
     
     
         125 . The device of  claim 123 , further comprising a brightness detector for measuring a brightness of an ambient environment of the display, the processor receiving the brightness measurement and further adjusting the amount of light from the illuminating light source and changing the range of the gray levels based on the brightness of the ambient environment.