Patent ID: 8864315
Filing Date: 2014-10-21
Classification: G03B

Abstract:
1. An image projection apparatus comprising: a light source apparatus which emits blue, green, and red illumination light; a digital micromirror device which modulates intensity of the blue, green, and red illumination light on an image display surface and which thereby forms blue, green, and red images; and a projection optical system which projects, while enlarging, the blue, green, and red images, wherein the image projection apparatus fulfills conditional formula (1) below: where when a mirror surface forming a pixel on the image display surface of the digital micromirror device is referred to as a pixel surface, reflected light produced as a result of a light ray along an illumination optical axis being mirror-reflected on the pixel surface is referred to as mirror-reflected light, an angle between, of diffracted light produced as a result of a blue light ray along the illumination optical axis being diffracted on the digital micromirror device, a part traveling in a direction closest to the mirror-reflected light and a normal line to the image display surface is defined as a blue light diffraction angle βB, an angle between, of diffracted light produced as a result of a green light ray along the illumination optical axis being diffracted on the digital micromirror device, a part traveling in a direction closest to the mirror-reflected light and a normal line to the image display surface is defined as a green light diffraction angle βG, and an angle between, of diffracted light produced as a result of a red light ray along the illumination optical axis being diffracted on the digital micromirror device, a part traveling in a direction closest to the mirror-reflected light and a normal line to the image display surface is defined as a red light diffraction angle βR, then Δ represents a largest among the diffraction angles βB, βG, and βR, FI represents an f-number of the illumination light, and FP represents an f-number of the projection optical system.