Patent ID: 9268122
Filing Date: 2016-02-23
CPC Classification: G01J,G02B

Claim Text:
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; and 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 an image sensor is located on a third reflected light path and configured to receive the third reflected light; wherein a primary mirror surface is an xy polynomial surface up to the sixth order; a secondary mirror surface is an x′y′ polynomial surface up to the sixth order; and a tertiary mirror surface is an x″y″ polynomial surface up to the sixth order.