| 摘要 |
<p>PROBLEM TO BE SOLVED: To achieve a projection optical system that uses a lens system and a concave mirror, and can effectively suppress an increase in diameter of the lens system and an increase in the area of the mirror surface of the concave mirror.SOLUTION: A projection optical system is used in an image display device that projects an image for projection displayed on an image display surface of an image display element on a projection target surface with an oblique ray to be enlarged and displayed. The projection optical system includes a lens system 10, concave mirror 20, and reflection mirror 30 that has a substantially planar reflection surface, guides the light for projection from the image display surface sequentially in order to the lens system 10, concave mirror 20, and reflection mirror 30 to the projection target surface, and forms the light for projection into an image on the projection target surface mainly by the imaging effect of the lens system 10 and concave mirror 20.</p> |
