Abstract: A system for measuring light intensity distribution is provided and set in a vacuum environment. The system for measuring light intensity distribution comprises a carbon nanotube array located on a surface of a substrate, a reflector, an imaging element and a cooling device. The substrate is cooled by the cooling device to make a contacting surface between the substrate and the carbon nanotube array maintain a constant temperature. The carbon nanotube array is irradiated by a light source to make the carbon nanotube array radiate a visible light, and the substrate is continuously cooled to make the contact surface between the substrate and the carbon nanotube array maintain the constant temperature. The visible light is reflected with the reflector. The visible light reflected by the reflector is imaged with the imaging element to obtain the light intensity distribution of the light source.

Abstract: An initial system and a constraint condition are established. All freeform surfaces are obtained by surface fitting the feature data points to form a first freeform surface imaging optical system. The first freeform surface imaging optical system is taken as the initial system for multiple iterations to obtain a second freeform surface imaging optical system. The second freeform surface imaging optical system is taken as a first base system. A first surface freedom of the first base system is selected, the values nearby the first surface freedom is selected, and surface positions and tilts of the first base system are changed to obtain a third freeform surface imaging optical system that satisfies the constraint condition. A second base system is selected and the method above is repeated. The freeform surface imaging optical system is obtained until all freedoms for surface positions and tilts have been used.

Abstract: A method for designing illumination system with freeform surface, the method comprising: presupposing a plurality of expected light spots; establishing an initial system, wherein the initial system comprises a plurality of collimated light sources, a plane lens and a target plane; designing a sphere lens to replace the plane lens, and obtaining a before-construction-iteration illumination system; selecting a plurality of feature rays and obtaining a plurality of target points; taking the before-construction-iteration illumination system as an initial construction-iteration system, and obtaining an after-construction-iteration illumination system with freeform surface by making multiple construction-iteration, wherein the illumination system with freeform surface is configured to form the plurality of expected light spots.

Abstract: An off-axis hybrid surface three-mirror optical system comprises a primary mirror, a secondary mirror, a tertiary mirror, and an image sensor. A reflective surface of the primary mirror is a sixth-order polynomial freeform surface of xy. A reflective surface of the secondary mirror is a sixth-order polynomial aspheric surface of xy. A reflective surface of the a tertiary mirror is a spherical surface of xy.

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: An illumination system with freeform surface comprises a plurality of collimated light sources having same parameters and a freeform surface lens comprising a first freeform surface and a second freeform surface, wherein formula of the first freeform surface and the second freeform surface is expressed as follows: z = c ? ( x 2 + y ? ? 2 ) 1 + 1 - ( 1 + k ) ? c 2 ? ( x 2 + y 2 ) + ? m ? ? n ? A mn ? x m ? y n , in which c is the curvature of the conic surface at the vertex, k is the conic constant, Amn represents the xy polynomials coefficient, m+n?2 and both m and n are even, beams emitted by the plurality of collimated light sources pass through the freeform surface lens to form a plurality of light spots on a target plane.

Abstract: An initial system and a constraint condition are established. All freeform surfaces are obtained by surface fitting the feature data points to form a first freeform surface imaging optical system. The first freeform surface imaging optical system is taken as the initial system for multiple iterations to obtain a second freeform surface imaging optical system. The second freeform surface imaging optical system is taken as a first base system. A first surface freedom of the first base system is selected, the values nearby the first surface freedom is selected, and surface positions and tilts of the first base system are changed to obtain a third freeform surface imaging optical system that satisfies the constraint condition. A second base system is selected and the method above is repeated. The freeform surface imaging optical system is obtained until all freedoms for surface positions and tilts have been used.

Abstract: A freeform surface off-axial three-mirror image-side telecentric optical system comprises a primary mirror, a secondary mirror, a tertiary mirror and an image sensor. The secondary mirror is the aperture stop. A reflective surface of the primary mirror is a fourth-order polynomial freeform surface of xy. Each of a reflective surface of the secondary mirror and a reflective surface of the tertiary mirror is a sixth-order polynomial freeform surface of xy.

Abstract: A method for designing a oblique camera lens comprising: step (S1), establishing an initial system, the initial system comprises a primary mirror initial structure, a secondary mirror initial structure, and a tertiary mirror initial structure; step (S2), building a new image relationship; step (S3), keeping the primary mirror initial structure and the secondary mirror initial structure unchanged; selecting a plurality of first feature rays; step (S4), keeping the secondary mirror initial structure and the tertiary mirror unchanged; selecting a plurality of fields and a plurality of second feature rays.

Abstract: A oblique camera lens includes: a primary mirror configured to reflect a light ray to form a first reflected light; a secondary mirror located on a first path of light reflected from the primary mirror and configured to reflect the first reflected light to form a second reflected light; a tertiary mirror located on a second path of light reflected from the secondary mirror and configured to reflect the second reflected light to form a third reflected light; and an image sensor located on a third path of light reflected from the tertiary mirror and configured to receive the third reflected light; wherein each of the first reflecting surface and the third reflecting surface is a sixth order xy polynomial freeform surface; and a field of view of oblique camera lens in an Y-axis direction is greater or equal to 35° and less than or equal to 65°.

Abstract: A design method of freeform imaging lens with a wide linear field-of-view (FOV) is provided. A initial freeform imaging lens is developed, and the initial freeform imaging lens includes a first lens surface and an entrance pupil spaced from each other, wherein the FOV of the system 2? (±?) is divided into 2k+1 sampling fields with equal interval ?? between each two adjacent sampling fields. Each two adjacent sampling fields are taken as one group. Two constraints are employed to calculate the plurality of data points of the first lens surface to obtain a front surface of the freeform imaging lens. The data points are calculated based on Snell's law, and a curve is obtained through the data points. A back surface is added to approximately keep the previous outgoing direction of rays from the front surface.

Abstract: An off-axis aspheric three-mirror optical system comprises a primary mirror, a secondary mirror, and a tertiary mirror. Relative to a first three-dimensional rectangular coordinates system in space, a second three-dimensional rectangular coordinates system is defined by a primary mirror location, a third three-dimensional rectangular coordinates system is defined by a secondary mirror location, and a fourth three-dimensional rectangular coordinates system is defined by a tertiary mirror location. The primary mirror in the second three-dimensional rectangular coordinates system, the secondary mirror in the third three-dimensional rectangular coordinates system, and the tertiary mirror in the fourth three-dimensional rectangular coordinates system are all sixth-order polynomial aspheric.

Abstract: A method for designing an off-axis aspheric optical system comprises establishing an initial system and selecting a plurality of feature rays Ri (i=1, 2 . . . K); solving a plurality of feature data points (P1, P2, . . . Pm) to obtain an initial off-axis aspheric surface Am by surface fitting the plurality of feature data points (P1, P2, . . . Pm), wherein m is less than K; introducing an intermediate point Gm to solve a (m+1)th feature data point Pm+1, and fitting a plurality of feature data points (P1, P2, . . . Pm, Pm+1) to obtain an off-axis aspheric surface Am+1; repeating such steps until a Kth feature data point PK is solved, and fitting a plurality of feature data points (P1, P2, . . . PK) to obtain an off-axis aspheric surface AK; and repeating above steps until all the aspheric surfaces of the off-axis aspheric optical system are obtained.

Abstract: A design method of LED freeform surface illumination system is provided. A light emitting angle of a LED point light source is divided into three regions. Each region can form a rectangular light spot on a light receiving surface. A mapping relationship of each region on the receiving surface is obtained. A light redistribution design for the LED point light source is performed and a system of first order partial differential equations of a freeform surface is achieved. A system of first order quasi linear differential equations of the freeform surface is obtained. A plurality of freeform surface data is obtained by solving the system of first order quasi linear differential equations. The freeform surface is obtained by surface fitting the plurality of freeform surface data.

Abstract: An off-axis three-mirror optical system with freeform surfaces comprised an aperture, a primary mirror, a secondary mirror, a tertiary mirror, and a detector. The aperture is located on an incident light path. The primary mirror is located on an aperture side. The secondary mirror is located on a primary mirror reflected light path. The tertiary mirror is located on a secondary mirror reflected light path. The detector located on a tertiary mirror reflected light path. The primary mirror and the tertiary mirror have a same fifth-order polynomial freeform surface expression. The primary mirror reflected light path, the secondary mirror reflected light path and the tertiary mirror reflected light path overlap with each other.

Abstract: A construction method of freeform surface shape based on XY-polynomial obtains a plurality of data points of a freeform surface according to an object point and an imaging point in a three-dimensional Cartesian coordinates system Oxyz. Each of the plurality of data points comprises a coordinate value Qi and a normal vector Ni. A first sum of squares e1(P) of coordinate differences in z direction between the coordinate value Qi and the freeform surface is applied, and by a second sum of squares e2(P) between the normal vector Ni of the data points and a normal vector ni of the freeform surface, a modulus of vector differences is acquired. An evaluation function ƒ(p)=e1(P)+we2(P) is proposed and a plurality of freeform surface shapes obtained by selecting and applying different weightings. A final freeform surface shape ?opt is chosen from the plurality of freeform surface shapes.

Abstract: An off-axis three-mirror optical system with freeform surfaces comprised an aperture, a primary mirror, a secondary mirror, a tertiary mirror, and a detector. The aperture is located on an incident light path. The primary mirror is located on an aperture side. The secondary mirror is located on a primary mirror reflected light path. The tertiary mirror is located on a secondary mirror reflected light path. The detector located on a tertiary mirror reflected light path. The primary mirror and the tertiary mirror have a same fifth-order polynomial freeform surface expression. The primary mirror reflected light path, the secondary mirror reflected light path and the tertiary mirror reflected light path overlap with each other.

Abstract: An off-axis three-mirror optical system with freeform surfaces comprised an aperture, a primary mirror, a secondary mirror, a tertiary mirror, and a detector. The aperture is located on an incident light path. The primary mirror is located on an aperture side. The secondary mirror is located on a primary mirror reflected light path. The tertiary mirror is located on a secondary mirror reflected light path. The detector located on a tertiary mirror reflected light path. The primary mirror and the tertiary mirror have a same fifth-order polynomial freeform surface expression. The primary mirror reflected light path, the secondary mirror reflected light path and the tertiary mirror reflected light path overlap with each other.

Abstract: An off-axial three-mirror optical system with freeform surfaces includes a primary mirror, a secondary mirror, a tertiary mirror, and an image sensor. The primary mirror is located on an incident light path. The secondary mirror is located on a primary mirror reflecting light path. The tertiary mirror is located on a secondary mirror reflecting light path. The image sensor is located on a tertiary mirror reflecting light path. A primary mirror surface and a tertiary mirror surface are all xy polynomial freeform surfaces up to a fifth order. A secondary mirror surface is a planar surface.

Abstract: An illumination system defined a primary optical axis is provided. The illumination system comprises a light source, a first lens group, an integrator rod, and a second lens group successively located on the primary optical axis. The light source is configured to output a light. The first lens group is configured to reduce an aperture angle of the light to about 27 degrees. The integrator rod is configured to make the light uniformly. The second lens group is configured to amplify an illumination field of the light and reduce the aperture angle of the light to about 3 degrees.