Patent ID: 9568717
Date: 2017-02-14
CPC Classifications: G02B

Claim:
1. An off-axis three-mirror optical system with freeform surfaces comprising: a primary mirror located on a path of a light ray from a object space and configured to reflect the light ray to form a first reflected light, wherein the primary mirror comprises a first reflecting surface; a secondary mirror located on a first path of light reflected from the primary mirror and configured to reflect the first reflected light to form a second reflected light, wherein the secondary mirror comprises a second reflecting surface, and the secondary mirror is an aperture stop; a tertiary mirror located on a second path of light reflected from the secondary mirror and configured to reflect the second reflected light to form a third reflected light, wherein the tertiary mirror comprises a third reflecting surface; and an image sensor located on a third path of light reflected from the tertiary mirror and configured to receive the third reflected light; wherein each of the first reflecting surface and the third reflecting surface is a sixth order xy polynomial freeform surface, the second reflecting surface is a spherical surface; and a first field of view of the off-axis three-mirror optical system with freeform surfaces in a Y-axis direction is greater or equal to 65°, a second field of view of the off-axis three-mirror optical system with freeform surfaces in an X-axis direction is greater or equal to 0.8°.