Patent ID: 9703084
Date: 2017-07-11
CPC Classifications: G02B

Claim:
1. An off-axial three-mirror optical system with freeform surfaces comprising: a primary mirror located on an incident light path, and configured to reflect an incident light to form a first reflected light; and a first three-dimensional rectangular coordinates system (X, Y, Z) is defined by a primary mirror vertex as a first origin; a secondary mirror located on a first reflected light path, and configured to reflect the first reflected light to form a second reflected light; a secondary mirror reflecting surface is a stop surface; a second three-dimensional rectangular coordinates system (X′, Y′, Z′) is defined by a secondary mirror vertex as a second origin; and the second three-dimensional rectangular coordinates system (X′, Y′, Z′) is obtained by moving the first three-dimensional rectangular coordinates system (X, Y, Z) along a Z-axis negative direction; a tertiary mirror located on a second reflected light path, and configured to reflect the second reflected light to form a third reflected light; a third three-dimensional rectangular coordinates system (X″, Y″, Z″) is defined by a tertiary mirror vertex as a third origin; and the third three-dimensional rectangular coordinates system (X″, Y″, Z″) is obtained by moving the second three-dimensional rectangular coordinates system (X′, Y′, Z′) along a Z′-axis positive direction; and a detector located on a third reflected light path and configured to receive the third reflected light; wherein a primary mirror surface is an xy polynomial freeform surface up to a fifth order, and an xy polynomial freeform surface equation is wherein, c represents surface curvature, k represents conic constant, and A 2 ˜A 20 represent coefficients; a tertiary mirror surface is an x″y″ polynomial freeform surface up to a fifth order, and an x′y′ polynomial freeform surface equation is wherein c″ represents surface curvature k″ represents conic constant and A 2 ″˜A 20 ″ represent coefficients; and a secondary mirror surface is a planar surface.