Polarizing unit, polarizing illumination device using same polarizing unit and projection display device using same polarizing illumination device

摘要

A small polarizing illumination device is provided which can apply light effectively to a small-sized liquid crystal display device at a reduced diverging angle. The above device has a light source lamp, a reflecting mirror, a reflecting device with an opening, a square-wave plate, a rod integrator, a polarized light separating unit, and a condenser lens, in which the reflecting device with an opening, square-wave plate, rod integrator, and polarized light separating unit can be integrally arranged. The device can be made small. Since linearly polarized light component not transmitting through but being reflected off the polarized light separating unit transmits through the quarter-wave plate twice before again entering the polarized light separating unit after having been reflected off the above reflecting device or having transmitted through its opening portion and having been condensed again by the reflecting device and is converted and can contribute to illumination, thus improving efficiency of using the light source.