Patent ID: 6535195
Filing Date: 2003-03-18
Classification: G09G

Abstract:
A display system comprising:an array of light valves arranged in rows and columns in a plane, wherein the total number of said rows is a positive integer N, each said light valve having a first and second electrical input, said light valves having a range of transmittance of light for pixel values in an addressing range of voltage applied between said inputs, said light valves substantially blocking light below said addressing range of voltage applied between said inputs, said light valves transmitting light within a turn-on time after said applied voltage increases to a value in said addressing range of voltage, said light valves substantially blocking light again within a turn-off time after said applied voltage returns to a value below said addressing range of voltage, an array of row drivers which each apply a select voltage waveform through a row conductor to said first inputs of said light valves disposed in one of said rows of light valves, an array of column drivers which each apply a data voltage waveform through a column conductor to said second input of each said light valve disposed in one of said columns of light valves, a backlight comprising an array of backlight segments arranged in a plane parallel to said plane of said light valves, each said segment being positioned to illuminate a corresponding subfield of M contiguous said rows of said light valves as seen from a first viewing-angle range in planes perpendicular to said rows of light valves, wherein said display system addresses said array of light valves in a field containing Q+1 contiguous subfields, where Q is a non-negative integer, by applying specific select voltage waveforms to said row conductors and computed data voltage waveforms to said column conductors connected to said light valves in said field thereby impressing voltages in said addressing range between said first input and said second input of said light valves in said field, wherein, further, said display system displays one of said subfields by causing said corresponding backlight segment to illuminate said light valves in said one subfield after said one subfield has been addressed for at least said turn-on time, said illumination continuing for an integration time while said addressing continues for a total addressing time, said light valves transmitting said illumination in proportion to predetermined said pixel values for each said light valve in said one subfield, wherein, further, N/M is a positive integer and said system displays an image in a frame time T by sequentially displaying said N/M subfields of said image in consecutive periods MT/N, said backlight segment illuminating said corresponding subfield of said light valves only after said corresponding subfield has been addressed for at least Q said periods MT/N and during a final said period of said addressing time lasting for (Q+1)MT/N, wherein, further, said addressing and said illuminating advance by one subfield after each said period MT/N, thereby allowing consecutive subfields to be illuminated by said corresponding backlight segments in consecutive said periods MT/N to display said images even if said turn-on time is longer than said period MT/N, wherein, finally, said system displays moving images by receiving and displaying multiple frames at a frame rate which allows at least said turn-off time between times when said subfields are addressed, said integration time being a small fraction of said frame time T which is the reciprocal of said frame rate thereby reducing smearing visual effects which occur if said light valves are illuminated when said transmittance is uncontrolled and at other times in said frame time T when said pixel values lag said moving images.