| 摘要 |
PURPOSE:To attain more miniaturization and compression of an optical system by arranging oppositely a couple of plane mirrors leading a light to an image forming lens after reflecting it plural number of times and tilting a little the plane mirrors from the parallel state so as to widen the interval at the emitting position of the image forming lens side more than the interval at the incident position of an original image. CONSTITUTION:A couple of plane mirrors 29, 30 leading the luminous flux to the image forming lens 32 while being reflected for plural number of times arranged nearly in parallel are provided, the mirrors are tilted to give the difference of wide and narrow for the interval between the plane mirrors so as to widen the interval of the image forming lens side. Thus, the condition that the image forming lens is arranged at the side between the plane mirrors is satisfied without giving the interference to the luminous flux, while the miniaturization in the direction of the opposed face is ensured so as to reduce the useless space in the reflected direction caused by plural number of times of reflections thereby miniaturizing the optical system in the reflected direction, then the optical length is compressed effectively.
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