Apparatus for enhancing contrast ratio in projection system, controls light emission time rate of light emitting diodes by comparing extracted mean value of input image signals with preset reference value

摘要

An image drive unit (210) extracts the mean level value of input red, blue, green image signals, to be displayed within a predetermined time. A light emitting diode controller (220) controls the light emission time rate of light emitting diodes (232,234,236) of illumination optical system by comparing extracted mean value with a preset reference value. Independent claims are also included for the following: (1) a light projection system; and (2) a method of enhancing a contrast ratio in light emission driving type projection system.