Patent ID: 8598503

Claim:
A projection display apparatus provided with an array light source in which a plurality of solid state light sources that emit light of the same color are disposed in an array, comprising: a sensor provided on a light path of light emitted from the array light source, and configured to detect an amount of light emitted from the plurality of solid state light sources that emit light of the same color; an acquisition unit configured to acquire an amount of light of a measurement target light source which is any one of the plurality of solid state light sources that emit light of the same color, based on the difference between the amount of light detected by the sensor at time t and the amount of light detected by the sensor at time t+1; a reference light amount storage configured to store a reference amount of light of an amount of light emitted from each of the plurality of solid state light sources; a light source controller configured to control the amount of light emitted from each of the plurality of solid state light sources and wherein the solid state light sources are controlled sequentially one by one in a period in which lights of the same color are to be emitted, so that the acquisition unit acquires the amount of light of the measurement target light source; and a determination unit configured to determine whether or not the measurement target light source has deteriorated, in accordance with a result of a comparison between the amount of light of the measurement target light source acquired by the acquisition unit, and the reference amount of light, wherein the light source controller sequentially controls the amounts of light of the respective solid state light sources one by one, in a turn-off phase where the emission of the light from the array light source is terminated by turning off the projection display apparatus, and the acquisition unit acquires the amount of light of the measurement target light source, in accordance with the amount of light detected by the sensor in the turn-off phase.