Lcd Projection Display Color Uniformity

Large screen electrical display devices play an important role in many areas. Among these technologies, the projection display is the most practical one, because of its lowest cost and most convenient use. Liquid Crystal Display (LCD) projectors occupy the most part of the market of the projection display devices. Because the good color uniformity of the LCD projector is highly required by many practical applications, it becomes a crucial factor to evaluate the projector's performance. This thesis focuses on the color uniformity of the LCD projection display technology.First, the thesis introduces the actuality and development of the display industry. Three kinds of present projection display techniques have been discussed: LC projection display, DLP (Digital Light Processor) projection display and LCOS (Liquid Crystal on Silicon) projection display, especially the advantages and disadvantages of color combination techniques. In addition, the actuality of the LCD projection display's color uniformity research is represented in this part.Second, the thesis proposes the evaluation method of the color uniformity of LCD projection display based on Uniform Color Space. In addition, the theoretical analysis of the color non-uniformity of LCD projection has been done; and the results of the computer-aided simulation based on ASAP are given to validate the analysis: there are two reasons that caused the color non-uniformity of LCD projection.Based on the analysis above, a system, which can measure and correct the color uniformity of the white of the three-panel LCD projector automatically, is proposed. With the precise calibration of the two-dimensional CCD, the system can measure the two-dimensional brightness distribution of the three primary colors of the LCD projector based on the CCD camera by time; and then, the color uniformity distribution of the white of the LCD projector can be calculated by the formula of color combination. Based on the measurement results, the computer would transfer the correction values to the registers of the projector to adjust the partial transmission ration of three LCD panels to improve the color uniformity. The experiment results validate that he system can measure and correct color uniformity of LCD projectors accurately and the system can be used in the production of LCD projectors.Finally, the conclusion and future research direction are given.