Abstract: The present application relates to an off-axis two-mirror infrared imaging system including a primary reflecting mirror and a secondary reflecting mirror. The primary reflecting mirror is located on the incident light path of an incident infrared light beam and reflects the incident infrared light beam to form a first reflected light beam. The secondary reflecting mirror is located on the reflection light path of the primary reflecting mirror, and is used to reflect the first reflected light beam to form a second reflected light beam. The second reflected light beam reaches an image surface after passing through the incident infrared light beam. The reflective surfaces of the primary reflecting mirror and the secondary reflecting mirror are freeform surfaces. The secondary reflecting mirror and the image plane are respectively located on both sides of the incident infrared light beam.

Abstract: A method for designing an imaging optical system is a point-by-point calculation method based on characteristic light rays (FLR) and characteristic data points (FDP). The basic function of the point-by-point calculation method includes the following steps: according to the given object-image relationship, based on Fermat's principle and the law of retraction and reflection, calculating the propagation path of the FLR passing through a system and the FDP on each optical surface, to obtain a surface shape equation of each optical surface by fitting; and repeating the above process, to solve the surface shape equation of each optical surface one by one, and finally complete the design and solution of the entire imaging optical system.

Abstract: A freeform surface off-axial three-mirror imaging system is provided. The freeform surface off-axial three-mirror imaging system comprises a primary mirror, a secondary mirror, and a compensating mirror. The primary mirror, the secondary mirror, and the compensating mirror are located adjacent and spaced away from each other. A surface shape of each of the primary mirror and the secondary mirror is a quadric surface. The primary mirror is used as an aperture stop. A surface shape of the compensating mirror is a freeform surface. A light emitted from a light source is reflected by the primary mirror, the secondary mirror, and the compensating mirror to form an image on an image plane.

Abstract: A freeform surface optical telescope imaging system is provided. The freeform surface optical telescope imaging system comprises a primary mirror, a secondary mirror, a compensating mirror, and a spherical mirror. The primary mirror, the secondary mirror, the compensating mirror, and the spherical mirror are spaced from each other. A surface shape of each of the primary mirror and the secondary mirror is a quadric surface. The primary mirror is used as an aperture stop. A surface shape of the compensating mirror is a freeform surface. A surface shape of the spherical mirror is a spherical surface. A light emitted from a light source would be reflected by the primary mirror, the secondary mirror, the compensating mirror, and the spherical mirror to form an image on an image plane.

Abstract: A method for designing a freeform concave grating imaging spectrometer includes selecting a series of light rays incident from different positions of a slit as characteristic light rays. The coordinates and normal directions of characteristic data points at intersections of the characteristic light rays and a surface of a freeform concave grating are calculated. A freeform surface shape of the freeform concave grating is obtained by fitting, so that an initial structure is obtained. Then the initial structure is optimized.

Abstract: The present application relates to a nonsymmetric freeform surface optical system including a primary reflecting mirror, a secondary reflecting mirror, and a tertiary reflecting mirror. A light beam from an object is reflected on the primary reflecting mirror to form a first reflected light beam, the first reflected light beam irradiates the secondary reflecting mirror and is reflected to form a second reflected light beam, the second reflected light beam irradiates the third reflecting mirror and is reflected to form a third reflected light beam, and the third reflected light beam reaches an image surface to form an image. The nonsymmetric freeform surface optical system has no rotational symmetry and no meridional symmetry.

Abstract: An imaging optical system includes a primary reflecting mirror, a secondary reflecting mirror, a tertiary reflecting mirror, and an aperture stop. The imaging optical system has a field of view, a focal length of the field of view that is defined as FFL, and an effective aperture of a field of view entrance pupil that is defined as FEPD. The FFL and the FEPD at a central field of view are greater than that at the edge field of views, and the FFL and the FEPD change continuously.

Abstract: A method for analyzing distribution of tolerances on a freeform surface in an optical system. Establishes a freeform surface imaging optical system. A plurality of fields is selected, and maximum and minimum margins of wavefront errors in each field are defined. One freeform surface in one field is selected, an isolated point jumping model is established, and an isolated point is placed in different areas of the freeform surface of the one field. A local figure error with extreme values corresponding to each field is resolved, based on the maximum and minimum margins of wavefront errors, and the local surface tolerance distributions of the freeform surface in the plurality of fields are integrated together.

Abstract: The present application relates to a method for designing a nonsymmetric freeform surface optical system, and the method including the following steps establishing an initial plane system. The initial plane system is consistent with the expected system structure, but there is no focal power in the initial plane system. The image plane tilt angle of the initial plane system is defined as ?. The point-by-point method is used to calculate the coordinates and normal vectors of the data points used to construct the freeform surface. The iterative optical system is obtained by iteration; and the iterative optical system is optimized.

Abstract: The present application relates to a nonsymmetric freeform surface optical system including a primary reflecting mirror, a secondary reflecting mirror, and a tertiary reflecting mirror. A light beam from an object is reflected on the primary reflecting mirror to form a first reflected light beam, the first reflected light beam irradiates the secondary reflecting mirror and is reflected to form a second reflected light beam, the second reflected light beam irradiates the third reflecting mirror and is reflected to form a third reflected light beam, and the third reflected light beam reaches an image surface to form an image. The nonsymmetric freeform surface optical system has no rotational symmetry and no meridional symmetry.

Abstract: A method for designing a freeform concave grating imaging spectrometer includes selecting a series of light rays incident from different positions of a slit as characteristic light rays. The coordinates and normal directions of characteristic data points at intersections of the characteristic light rays and a surface of a freeform concave grating are calculated. A freeform surface shape of the freeform concave grating is obtained by fitting, so that an initial structure is obtained. Then the initial structure is optimized.

Abstract: A method of designing an freeform surface off-axial three-mirror imaging system is provided. The method includes: establishing an initial system and T (T?2) object-image relationships according to a design goal, and selecting M feature fields for each object-image relationship; using feature rays of the T object-image relationships to construct a freeform surface system by using the initial system; step (S3), the freeform surface system obtained in step (S2) is used as another initial system, using iterative process to reduce a deviation between actual intersection points and ideal target points of the feature rays and feature surfaces, iteratively reconstructing free-form surfaces in the free-form surface system.

Abstract: A method for designing an imaging optical system is a point-by-point calculation method based on characteristic light rays (FLR) and characteristic data points (FDP). The basic function of the point-by-point calculation method includes the following steps: according to the given object-image relationship, based on Fermat's principle and the law of retraction and reflection, calculating the propagation path of the FLR passing through a system and the FDP on each optical surface, to obtain a surface shape equation of each optical surface by fitting; and repeating the above process, to solve the surface shape equation of each optical surface one by one, and finally complete the design and solution of the entire imaging optical system.

Abstract: An imaging optical system includes a primary reflecting mirror, a secondary reflecting mirror, a tertiary reflecting mirror, and an aperture stop. The imaging optical system has a field of view, a focal length of the field of view that is defined as FFL, and an effective aperture of a field of view entrance pupil that is defined as FEPD. The FFL and the FEPD at a central field of view are greater than that at the edge field of views, and the FFL and the FEPD change continuously.

Abstract: A method for designing a hybrid surface optical system comprises establishing a first initial system; keeping the first initial system unchanged and calculating a plurality of first feature data points, and fitting the first feature data points to obtain a spherical surface; repeating such steps until all spherical surfaces are obtained; calculating a plurality of second feature data points, and fitting the plurality of second feature data points to obtain an aspheric surface; repeating such steps until all aspheric surfaces are obtained; calculating a plurality of third feature data points, and fitting the plurality of third feature data points to obtain a freeform surface; repeating such steps until all freeform surfaces are obtained.

Abstract: The present invention relates to a freeform surface reflective infrared imaging system comprising a primary mirror, a secondary mirror, a tertiary mirror, and an infrared light detector. Each reflective surface of the primary mirror, the secondary mirror, and the tertiary mirror is an xy polynomial freeform surface. A field of view of the freeform surface reflective infrared imaging system is larger than or equal to 40°×30°. An F-number of the freeform surface reflective infrared imaging system is less than or equal to 1.39.

Abstract: A freeform concave grating imaging spectrometer includes a slit, a freeform concave grating, and an image surface. The lights incident from the slit is irradiated on the freeform concave grating to be dispersed and reflected, to form a reflected light beam. The reflected light beam is irradiated on the image surface, so that the lights of different wavelengths incident from the slit are separated and imaged on the image surface.

Abstract: A method for designing freeform surface imaging system comprises: constructing a series of coaxial spherical systems with different optical power (OP) distributions; tilting all optical elements of each coaxial spherical system by a series of angles to obtain a series of off-axis spherical systems; finding all unobscured off-axis spherical systems; and then specifying a system size or structural constraints, and finding a series of compact unobstructed off-axis spherical systems; constructing a series of freeform surface imaging systems based on the series of compact unobstructed off-axis spherical system, and correcting the OP of entire system; improving an image quality of each freeform surface imaging systems and finding an optimal tilt angle of an image surface; and automatically evaluating an image quality of each freeform surface imaging system based on an evaluation metric, and outputting the freeform surface imaging systems that meet a given requirements.

Abstract: A freeform surface off-axial three-mirror imaging system comprising a primary mirror, a secondary mirror, a tertiary mirror, and a detector. The secondary mirror defines a first location and a second location. Each reflective surface of the primary mirror, the secondary mirror and the tertiary mirror is an xy polynomial freeform surface. A working distance of the freeform surface off-axial three-mirror imaging system is greater than 125 mm.

Abstract: The present application relates to an off-axis two-mirror infrared imaging system including a primary reflecting mirror and a secondary reflecting mirror. The primary reflecting mirror is located on the incident light path of an incident infrared light beam and reflects the incident infrared light beam to form a first reflected light beam. The secondary reflecting mirror is located on the reflection light path of the primary reflecting mirror, and is used to reflect the first reflected light beam to form a second reflected light beam. The second reflected light beam reaches an image surface after passing through the incident infrared light beam. The reflective surfaces of the primary reflecting mirror and the secondary reflecting mirror are freeform surfaces. The secondary reflecting mirror and the image plane are respectively located on both sides of the incident infrared light beam.