Projection display device and back projection display device using the display device

Abstract

A projection display apparatus includes a light source (1), an illumination system (8), a reflection system (9), a reflection-type light modulator (10), a lens element (11), and a projection system (12). The optical axis (8a) of the illumination system (8) and the optical axis (12a) of the projection system (12) are skew lines. The lens element (11) allows the exit pupil (8b) of the illumination system (8) to be conjugated substantially with the entrance pupil (12b) of the projection system (12). Thus, the reflection-type light modulator (10) and the projection system (12) can be arranged coaxially. Moreover, mechanical contact or interference between the optical components can be eliminated, and the space can be utilized efficiently. This configuration can provide an inexpensive compact projection display apparatus using a reflection-type light modulator.

Dependencies are inferred from the claim text.