Freeform surface imaging spectrometer system
AssigneesTsinghua University, Hon Hai Precision Industry Co., Ltd.
InventorsJun Zhu, Ben-qi Zhang, Guo-Fan Jin, Shou-Shan Fan
Life of this patent
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Abstract
A freeform surface imaging spectrometer system including a primary mirror, a secondary mirror, a tertiary mirror, and a detector is provided. The secondary mirror is a grating having a freeform surface shape, and the grating having the freeform surface shape is obtained by intersecting a set of equally spaced parallel planes with a freeform surface. A plurality of feature rays exiting from a light source is successively reflected by the primary mirror, the secondary mirror and the tertiary mirror to form an image on an image sensor. A reflective surface of each of the primary mirror, the tertiary mirror surface and the tertiary mirror is an xy polynomial freeform surface.
Claims16
A freeform surface imaging spectrometer system comprising:
- a primary mirror, wherein a global three-dimensional rectangular coordinate system (X0, Y0, Z0) is established in a space wherein a slit of the freeform surface imaging spectrometer system is located, an origin of the global three-dimensional rectangular coordinate system (X0, Y0, Z0) is an object point of a central field of view on the slit, and the global three-dimensional rectangular coordinate system (X0, Y0, Z0) comprises an X-axis, a Y-axis, and a Z-axis;
- and a first three-dimensional rectangular coordinates system (X, Y, Z) is established, a first origin of the first three-dimensional rectangular coordinates system (X, Y, Z) is a vertex of the primary mirror, and the first three-dimensional rectangular coordinates system (X, Y, Z) is obtained by moving the global three-dimensional rectangular coordinate system (X0, Y0, Z0) along a Z-axis positive direction of the Z-axis and a Y-axis positive direction of the Y-axis;
- and a reflective surface of the primary mirror in the first three-dimensional rectangular coordinates system (X, Y, Z) is an xy polynomial freeform surface;
- a secondary mirror being as an aperture stop, wherein the secondary mirror is a grating a grating pitch of the grating is ranged from about 0.004 millimeters to about 0.010 millimeters;
- and a second three-dimensional rectangular coordinates system (X′, Y′, Z′) is established, wherein a second origin of the second three-dimensional rectangular coordinates system (X′, Y′, Z′) is a vertex of the secondary mirror, and the second three-dimensional rectangular coordinates system (X′, Y′, Z′) is obtained by moving the global three-dimensional rectangular coordinate system (X0, Y0, Z0) along the positive direction of the Z-axis and a negative direction of the Y-axis;
- and a reflective surface of the secondary mirror in the second three-dimensional rectangular coordinates system (X′, Y′, Z′) is an x′y′ polynomial freeform surface;
- a tertiary mirror, wherein a third three-dimensional rectangular coordinates system (X″, Y″, Z″) is established, and the third three-dimensional rectangular coordinates system (X″, Y″, Z″) is obtained by moving the global three-dimensional rectangular coordinate system (X0, Y0, Z0) along the positive direction of the Z-axis and the positive direction of the Y-axis;
- and a reflective surface of the tertiary mirror in the third three-dimensional rectangular coordinates system (X″, Y″, Z″) is an x″y″ polynomial freeform surface;
- and
- a detector, wherein a plurality of feature rays exiting from a light source is successively reflected by the primary mirror, the secondary mirror and the tertiary mirror and forms an image on the detector,
- wherein a spectral resolution of the freeform surface imaging spectrometer system is equal to or more than 2 nanometers.
Dependencies are inferred from the claim text.