SYNCHRONIZING OPTICAL SCAN AND ELECTRICAL ADDRESSING OF A SINGLE-PANEL, SCROLLING COLOR LCD SYSTEM

摘要

The electrical scan which applies data for one of the red, green and blue colors of a liquid crystal display (LCD) to the pixels of each row of the display and the optical scan of the panel with the color stripe of that color are synchronized to ensure sufficient time for the switching of the pixel from one color value to another. Synchronizing the electrical and optical scans creates a better color rendition of the displayed image without any inter-color mixing artifacts. Arrays or groups of photosensors are positioned laterally adjacent the active portion of the panel and each array is covered by a filter which passes light of only one of the three colors (red, green and blue) used in the display. The color stripes providing the optical scan are scrolled simultaneously over both the active portion of the panel and the arrays of sensors, with the electrical signals from the sensors providing an indication of the positions of the leading and trailing edges of each color stripe at each instant, and thus the instantaneous velocity of each stripe. The signals from the sensors are provided to a control circuit which determines the order in which the rows of pixels are addressed and for which of the colors to provide data in each addressed location in order to maintain the critical switching time in spite of variations in relative velocities of the three color stripes.