ILLUMINATION DEVICE AND PROJECTION DISPLAY DEVICE

摘要

An illumination device is provided with a light source, and an iris (30) for adjusting the amount of emission light by transmitting a portion of the emission light emitted from the light source and blocking the rest of the emission light. A plurality of recesses or protrusions is periodically arranged at a pitch of no less than 100 times the wavelength of the emission light at least at a portion of the region of the iris (30) that blocks the emission light.