Patent ID: 9405109
Filing Date: 2016-08-02
CPC Classification: G02B

Claim Text:
1. An off-axial three-mirror optical system with freeform surfaces comprising: an aperture located on an incident light path; a primary mirror located on the incident light path and configured to reflect incident lights transmitting through the aperture to form a first reflected light; 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 tertiary mirror located on a second reflected light path and configured to reflect the second reflected light to form a third reflected light; and a detector located on a third reflected light path and configured to receive the third reflected light; wherein a first three-dimensional rectangular coordinates system (X,Y,Z) is defined by a secondary mirror location, and a secondary mirror vertex is a first three-dimensional rectangular coordinates system (X,Y,Z) origin; a second three-dimensional rectangular coordinates system (X′,Y′,Z′) is defined by a primary mirror location and a tertiary mirror location, 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 positive direction; a primary mirror surface and a tertiary mirror surface have a same freeform surface equation, and the freeform surface equation is an x′y′ polynomial up to a sixth order; and a secondary mirror surface is an aspherical surface up to a tenth order.