PROJECTION-TYPE DISPLAY DEVICE

摘要

This projection-type display device comprises: a projection optical system having an illumination unit, a projection lens, and a light valve which modulates the illumination light supplied from the illumination unit on the basis of a video signal and emits the modulated light toward the projection lens; a polarization separation element which is disposed between the light valve and the projection lens and separates the incident light into first and second polarization components while emitting these polarization components in mutually different directions; and a detection optical system having an imaging element disposed at a position optically conjugate to the light valve. The light based on invisible light emitted along a plane near a projection surface is incident on the imaging element through the projection lens and the polarization separation element, and the projection-type display device is configured to satisfy the following conditional expression: d1 < β × d2 ………(1)