| 摘要 |
PROBLEM TO BE SOLVED: To provide a projection optical system which can achieve further miniaturization of a projector itself while making use of the advantage that distance from the projector to a screen can be reduced.SOLUTION: The projection optical system is for expanding and projecting an image being displayed on an image display element onto the screen and includes a first optical system 2 and a second optical system 3, 4 in order from the image display element 1 side. The first optical system 2 includes a plurality of lenses and is an optical system for forming an intermediate image of an image being displayed on the image display element. The second optical system includes a free-form surface mirror 4 and is an optical system for forming an image of the intermediate image onto a screen. The first optical system 2 has one or more aspherical lens having positive refractive power that continuously increases with increasing distance from an optical axis within an effective region though which light passes. |
