Projection type display apparatus, rear projector and multi-vision system

A projection type display apparatus comprising:

• an illumination optical system for collecting for collecting light radiated from a light source to form illumination light;
• a reflection type light valve for reflecting the illumination light to output modulated light forming an optical image;
• a projection lens system for projecting the optical image formed by the reflection type light valve;
• and a lens element with a positive power,
• wherein the lens element has a plurality of projections on one optical interface or both optical interfaces and is placed between the reflection type light valve and the projection lens system so that the illumination light passes through the lens element to illuminate the reflection type light valve, and modulated light output from the reflection type light valve passes through the lens element to be incident upon the projection lens system, and
• the plurality of projections are formed so that a pitch is ½ or less of a visible band wavelength and a height is one time or more of the pitch.

A projection type display apparatus comprising:

• an illumination optical system for collecting for collecting light radiated from a light source to form illumination light;
• a reflection type light valve for reflecting the illumination light to output modulated light forming an optical image;
• a projection lens system for projecting the optical image formed by the reflection type light valve;
• and a lens element with a positive power,
• wherein the reflection type light valve and the projection lens system are placed so that their optical axes are parallel to each other,
• the lens element is configured by cementing a plano-concave lens with a plano-convex lens with a refractive index larger than that of the piano-concave lens and is placed between the reflection type light valve and the projection lens system so that the illumination light passes through the lens element to illuminate the reflection type light valve, and modulated light output from the reflection type light valve passes through the lens element to be incident upon the projection lens system, and
• the plano-concave lens and the plano-convex lens are cemented with each other via a film having a refractive index larger than that of the piano-concave lens and smaller than that of the piano-convex lens, or a film whose refractive index is varied from that of the plano-concave lens to that of the plano-convex lens.