Video signal process for two-panel liquid crystal projector.

摘要

A video signal processing apparatus for use in a two-panel liquid crystal projector includes a matrix circuit (54) for receiving a luminance signal and colour signals output from a luminance/chroma processor (53) and generating colour signals in a different way from that of an existing matrix circuit. A matrix circuit (54) generates a new luminance signal by adding the minimum value of the colour difference signals to the luminance signal. The minimum value is subtracted from the respective colour difference signals to generate new colour signals. Another matrix circuit (54) generates colour signals and a luminance signal which are applied to a liquid crystal panel (57, 58) based on the minimum value of the colour signals which are obtained by the existing matrix circuit (54) instead of using the colour difference signals. The colour signals and luminance signal which are obtained by the respective matrix circuits (54) are used for light modulation for a colour liquid crystal panel (58) and white/black liquid crystal panel (57). Then, amplitude of the newly obtained luminance signal is controlled by an amplifier (66, 75) having an amplification factor based on a difference between light utilization efficiencies of the luminance signal and the colour signals which are displayed on a screen. Thus, an unnatural image phenomenon is removed and resolution and brightness can be improved. Further, disharmonization between the luminance signal component and the colour signal component can be prevented in view of the optical and signal processing conditions.