Off-axis aspheric three-mirror optical system

An off-axis aspheric three-mirror optical system comprising:

• a primary mirror located on an outgoing light path of rays;
• a secondary mirror located on a first reflected light path, which is from the primary mirror;
• a tertiary mirror located on a second reflected light path, which is from the secondary mirror;
• and
• an image sensor located on a third reflected light path, which is from the tertiary mirror;
• wherein a first three-dimensional rectangular coordinates system (x1, y1, z1) is defined in space, relative to the first three-dimensional rectangular coordinates system (x1, y1, z1), a second three-dimensional rectangular coordinates system (x2, y2, z2) is defined by a primary mirror location, a third three-dimensional rectangular coordinates system (x3, y3, z3) is defined by a secondary mirror location, and a fourth three-dimensional rectangular coordinates system (x4, y4, z4) is defined by a tertiary mirror location;
• in the second three-dimensional rectangular coordinates system (x2, y2, z2) a reflective surface of the primary mirror is a sixth-order polynomial aspheric of x2y2, and the sixth-order polynomial aspheric of x2y2 is:
• Z
• =
• c
• ⁢
• ⁢
• r
• 2
• 1
• +
• 1
• -
• (
• 1
• +
• k
• )
• ⁢
• c
• 2
• ⁢
• r
• 2
• +
• a
• 1
• ⁢
• r
• 4
• +
• a
• 2
• ⁢
• r
• 6
• ⁢
• ⁢
• r
• 2
• =
• x
• 2
• 2
• +
• y
• 2
• 2
• ,
• wherein, c represents surface curvature at quadratic surface vertex, k represents conic constant, a1 and a2 represent an aspherical term coefficient c=−0.001315 mm−1, k=0, a1=3.5869e-010, and a2=9.9633e-017;
• in the third three-dimensional rectangular coordinates system (x3, y3, z3), a reflective surface of the secondary mirror is a sixth-order polynomial aspheric of x3y3;
• and in the fourth three-dimensional rectangular coordinates system (x4, y4, z4), a reflective surface of the a tertiary mirror is a sixth-order polynomial aspheric of x4y4.