Projection display employing circular polarized light for reflection reduction

• Main Authors: ARUGA; SHUJI, HORIGUCHI; HIROSADA
• Format: Patent
• Language: English
• Published: 21.12.1999
• Edition: 6
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; PICTORIAL COMMUNICATION, e.g. TELEVISION

A projection display for preventing reflected light beams produced during optical modulation or light compositing from reinjecting into the modulating liquid crystal panel, as well as to convert projected light or light impinged into a light compositing system into a linearly polarized light beam, thereby projecting high-contrast, high-intensity images with minimal reflection errors. This display will preferably include a light source, an optical modulation system for modulating the light beam emitted from the light source according to a video signal using a liquid crystal panel having a polarizing plate or filter on the output surface thereof, a first phase plate provided on the output side of the polarizing plate for converting the linearly polarized light beam that has passed through the optical modulation system into a circularly polarized light beam, a second phase plate provided on the output side of the first phase plate for converting the circularly polarized light beam that has passed through the first phase plate into a linearly polarized light beam, and an optical projector system for projecting on a screen in enlarged fashion the resultant linearly polarized light beam that has passed through the second phase plate. The first and second phase plates are preferably disposed such that reflected light produced at interfaces between air and the first or second phase plates, or a light compositor are polarized at right angles to the light transmission axis of the interposing polarizing plate, thereby blocking their passage back to the liquid crystal panel.