| 摘要 |
PURPOSE:To multiply the quantity of light transmitted through the polarizing plate on the incident side of a liquid crystal light valve and to realize a high-brightness projected image by providing an optical means for converting non-polarized illuminating luminous flux which is emitted from a light source to linearly polarized light having a polarizing direction which should be made incident on the liquid crystal light valve. CONSTITUTION:The illuminating luminous flux 2 which is emitted from the light source 1 is in a non-polarized state and is separated to reflected S polarized light 30 and transmitted P polarized light 33a by the joint surface 20a of a polarizing and separating means. The reflected S polarized light is made incident on a polarizing and rotating means 21. The means 21 is constituted of mirrors 21a and 21b which are orthogonally crossed and emits the light after rotating the polarizing direction of the incident light by 90 deg.. Therefore, the S polarized light 30 made incident on the polarizing and rotating means is emitted as the P polarized light 31, which is transmitted through the polarizing and separating means 20 still as the P polarized light, reflected by an optical path conversion means 23 and made incident on the liquid crystal light valve 3 through a condenser lens 10 as the linearly polarized light 33b in the same polarizing and advancing directions as those of the transmitted P polarized light 33a. As a result, light energy about twice as much as in conventional practice is made incident on a liquid crystal layer and contributes to the display of an image. |
