Patent ID: 7177078
Filing Date: 2007-02-13
Classification: G03B,H04N

Abstract:
1. A projection type display apparatus, comprising: a light source for emitting an illumination light, an image display device, an illumination optical system for irradiating the illumination light from said light source to said image display device, and a projection optical system for projecting an image formed by said image display device; wherein said illumination optical system comprises wherein said illumination optical system is useable in both a predetermined first state and a second state satisfying condition formulas below. Here, Ø indicates a refracting power of an entire relay lens system (inverse number of focal length f), Ø11 indicates a refracting power of a first lens group in the first state, Ø12 indicates a refracting power of the second lens group in the first state, Ø21 indicates a refracting power of the first lens group in the second state, Ø22 indicates a refracting power of the second lens group in the second state, e