| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a projection optical device capable of projecting a video in a direction of 360°, that is, the full circumference with an optical system having simple constitution. <P>SOLUTION: The projection optical device comprises: a projection lens 2 made of a rotation-symmetry transparent lens body having positive power obtained by rotating a curved line including a part projecting in a radial direction orthogonal to a center axis 1 on a plane including the center axis 1 around the center axis 1; and an annular video display element arranged in rotation symmetry around the center axis along the curved image surface 3 of the projection lens 2. <P>COPYRIGHT: (C)2008,JPO&INPIT |
