| 摘要 |
PURPOSE: An optical system for projection type image display device is provided to reduce size of the device in a depthwise direction by constituting the optical system for the rear of the projection lens, into two stages. CONSTITUTION: An optical system comprises a light source(1) for radiating beam; a UV-IR cut filter(2) for transmitting only a visible light; fly eye lenses(3,5) for improving distribution of beam; a flat-type polarizing beam splitter(6) for polarizing beam; a plurality of reflector mirrors(4,8,24,26) for converting direction of beam; a dichroic mirror(10) for selecting beams of specific colors and reflecting selected beam; first to seventh condenser lenses(7,9,11,16,20,25,50) for condensing light; polarizing beam splitters(12,17,27,22) for reflecting or transmitting beams of a blue region, green region and a red region, in accordance with the polarizing state of each beam; LCDs(14,19,29) for forming and reflecting an image; λ/2 wavelength plates(15,21,30) and λ/4 wavelength plates(13,18,23,28) for changing polarizing state of beam; a dichroic prism(31) for synthesizing beams; and a projection lens(32) for projecting the synthesized beam. All the components excluding the projection lens are arranged in two rows in the rear of the projection lens. |
