ILLUMINATING OPTICAL SYSTEM, IMAGE DISPLAY UNIT AND METHOD OF ILLUMINATING SPACE MODULATION ELEMENT

摘要

Provided are an illumination optical system having superior color rendering properties while ensuring sufficient illuminance, an image display apparatus comprising the illumination optical system and a spatial modulation device illuminated by the illumination optical system, and a method of illuminating the spatial modulation device. A first light source (11), a second light source (21) having a different emission spectrum from an emission spectrum of the first light source (11), and a replacement optical system replacing light in a specific waveband in a luminous flux (L1) from the first light source (11) with a luminous flux (L2) from the second light source (21) are comprised, and the light in the specific waveband with weak light intensity in the luminous flux (L1) from the first light source (11) is replaced with the luminous flux (L2) with sufficient intensity from the second light source (21). Thereby, a white balance can be kept without reducing the illuminance more than necessary, and superior color rendering properties can be exhibited.