| 摘要 |
PURPOSE: A projection lens unit for a pico projector is provided to reduce the height of an array of lens, since only a part of lens surface is used when an image is projected. CONSTITUTION: A projection lens unit for a pico projector comprises an array of lens, a color composition prism, a cover glass and an image panel. The lens array comprises first ~ sixth lenses. The first ~ sixth lenses are arranged in sequence from a screen, on which an image is projected. The stop surface of a beam is formed so that a first surface of the first lens performs the function of an aperture stop, in which a ratio of the height of a beam passing the central axis of the lens array to the size of the first lens is approximately 1. A beam, which passes the sixth lens from the first lens, travels only in one direction of lens surface from the aperture stop. A part of lens surface, through which the beam does not pass, is cut and thus total height of the lens array decreases.
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