CN-116734763-B - Spliced aspheric surface characterization method based on CGH lens zero compensation detection light path

Abstract

The invention relates to the technical field of optical aspheric surfaces, in particular to a spliced aspheric surface characterization method based on a CGH lens zero compensation detection light path, which uses aspheric surface detection as a guide, uses interferometer incident wave front as a plane wave, a compensator as a single CGH lens and a diffraction surface as each parameter required by a zero compensation detection system of a binary optical surface 3 or a binary optical surface 4 according to a ray tracing method, a Snell law, a diffraction principle and an aplanatic principle based on a zero compensation detection principle, and is a type of aspheric surface customized according to the characterization method, namely a zero spliced aspheric surface. According to the spliced aspheric surface characterization method, the measurement scheme of the spliced aspheric surface can be determined in the design stage through mathematical description of the spliced aspheric surface, so that the parasitic light influence and projection distortion faced by CGH detection are avoided, the detection difficulty of the surface shape of the spliced aspheric surface is reduced, and the function that the zero-position spliced aspheric surface design can be detected is realized.

Inventors

• MA TAO
• ZHANG YULU
• ZENG XINYUE

Assignees

• 苏州大学

Dates

Publication Date

20260512

Application Date

20230531

Claims (6)

1. 1. The spliced aspheric surface characterization method based on the CGH lens zero compensation detection light path is characterized by comprising the following steps of: In a zero compensation detection system with an interferometer incident wavefront being plane wave and a compensator being a single CGH lens compensator, the light transmission caliber of a standard interferometer mirror is Wavelength of detected light is The single CGH lens compensator has a diffraction plane phase of Diffraction orders of The radius of curvature of the refracting surface is The center thickness of the single CGH lens compensator is The refractive index of the single CGH lens compensator material is The distance between the single CGH lens compensator and the aspheric surface is ; Constructing a zero compensation detection system according to the characterization parameters of the self-defined zero splicing aspheric surface, wherein the interferometer standard mirror detects parallel incidence of light rays, different heights and different diffraction orders correspond to different points on the aspheric surface, and different diffraction surface directions correspond to different points of the zero splicing aspheric surface respectively; In the zero compensation detection system, a single CGH lens compensator takes a plane binary optical surface as a reference, a phase function of a diffraction surface is a binary optical surface 3 or a binary optical surface 4 in rotational symmetry, wherein when the phase function of the diffraction surface is the binary optical surface 3, a zero splicing double aspheric surface is represented, and when the phase function of the diffraction surface is the binary optical surface 4, a zero splicing multiple aspheric surface is represented; the detection light is incident in plane wave, the single CGH lens compensator and the aspheric surface form a zero spherical aberration system, and the system follows the aplanatic principle; According to the parameter of the zero compensation detection system, determining the corresponding optical path of the parameter tracking light, and parallelly connecting expressions of the two optical paths to obtain the intersection point of the detection light and the aspheric surface The track equation of the point, namely the surface shape expression of the self-defined zero splicing aspheric surface; The zero splicing aspheric surface is a rotationally symmetrical curved surface, and the maximum effective caliber is determined by the actual light-transmitting caliber of the interferometer standard mirror; The binary optical surface 3 supports two concentric radial regions, each region has independent radius, conic curve, polynomial aspheric surface and diffraction phase distribution, when the phase function of the diffraction surface is the binary optical surface 3, only the diffraction phases of the two concentric radial regions are considered, and the surface of the binary optical surface 3 is provided with two radial coordinates And Divided into two regions, wherein ; The inner radial region from the center of the surface to the radial coordinates The phase expression of the inner region is: wherein Is the number of coefficients of the polynomial, Is the normalized radial aperture coordinate of the lens, Is that A kind of electronic device The coefficient of the power of the two, Is the diffraction order; the outer radial region being from the radial coordinates To radial coordinates The phase expression of the outer region is: In which the phase is shifted , Is the number of coefficients of the polynomial, Is the normalized radial aperture coordinate of the lens, Is that A kind of electronic device The coefficient of the power of the two, Is the diffraction order; so that the phase is continuous at the boundary between the inner region and the outer region, calculating In the time-course of which the first and second contact surfaces, The value of (2) is set to 0, the phase difference is an integral multiple of the wavelength, that is Wherein Is an arbitrary integer, and to satisfy the continuity of the boundary region phase, calculate And sets the value to 0.
2. 2. The method for characterizing a spliced aspheric surface based on a zero compensation detection light path of a CGH lens according to claim 1, wherein when a diffraction surface of the single CGH lens compensator faces an incident plane wave, detection light is emitted in parallel by an interferometer standard mirror, and the radial coordinate of the surface of the binary optical surface 3 is divided into an inner part And outside The area is used for detecting that the light parallel wave intersects with the inner CGH surface The point at which the current is to be measured, After the light rays of the diffraction orders are emitted, the light rays are intersected with the rear refraction surface Point, after refraction by the back surface, intersects with the aspheric surface A point, the incidence height of the detection light on the interferometer standard mirror is Detecting the intersection of the light parallel wave with the external CGH surface The point at which the current is to be measured, After the light rays of the diffraction orders are emitted, the light rays are intersected with the rear refraction surface Point, after refraction by the back surface, intersects with the aspheric surface A point, the incidence height of the detection light on the interferometer standard mirror is There is Will be And As a parameter of the aspherical surface shape, In the caliber section of the interferometer standard mirror , Within the equation is a continuous variable, In the aperture range of the interferometer standard mirror The inside is a continuous variable; When each parameter in the zero compensation detection system is fixed, the light height is detected 、 Incident by 、 Point to point 、 The point light ranges are the same at the moment 、 The locus function formed by the points is a zero splicing double aspheric formula which is characterized when the front surface of the single CGH lens compensator is a binary optical surface 3, and the parameter expression of the general form can be expressed as follows: ; ; Wherein the method comprises the steps of , ; According to the principle of aplanatism, when the radial coordinate of the diffraction surface is When in use, two detection light rays are selected, wherein one light ray is the center point of the diffraction surface of the single CGH lens compensator The outgoing light rays are in the path: Wherein, the method comprises the steps of, The point is the center vertex of the back surface of the single CGH lens compensator, The point is the central vertex of the aspheric surface, and the corresponding optical path is ; The other ray is a parametric trace ray, i.e., off-axis ray, with the path: according to the parameter of the zero compensation detection system, determining that the corresponding optical path of the parameter tracking light is Wherein Is that Dots and dots The distance between the points is such that, Is used for refracting light Intersection point on optical axis Dots and dots The distance between the points is such that, Is used for refracting light Intersection on optical axis Dots and dots The distance between the points; According to the principle of aplanatism, there are Obtaining On points and internal aspheres The distance between the points is ; To be used for When the point is the origin of coordinates and the front surface of a single CGH lens compensator in the zero compensation detection system is a binary optical surface 3, the zero splice is carried out on any point in the aspheric surface area inside the double aspheric surfaces The trajectory equation of (2) is: ; Wherein the method comprises the steps of Refractive light for the back surface of a single CGH lens compensator Included angle with the optical axis, Refractive light for the back surface of a single CGH lens compensator Intersection with optical axis Point-to-single CGH lens compensator back surface vertex Is a distance of (2); by the same token, when the radial coordinate of the diffraction plane is In the time-course of which the first and second contact surfaces, On points and external aspheres The distance between the points is Wherein Is that Dots and dots The distance between the points is such that, Is used for refracting light Intersection point on optical axis Dots and dots The distance between the points is such that, Is used for refracting light Intersection on optical axis Dots and dots The distance between the points; To be used for When the point is the origin of coordinates and the front surface of a single CGH lens compensator in the zero compensation detection system is a binary optical surface 3, the zero splice is carried out on any point of the external aspheric surface area of the double aspheric surfaces The trajectory equation of (2) is: ; Wherein the method comprises the steps of Refractive light for the back surface of a single CGH lens compensator Included angle with the optical axis, Refractive light for the back surface of a single CGH lens compensator Intersection with optical axis Point-to-single CGH lens compensator back surface vertex Is a distance of (2); the said Dots and The track equation of the point is the surface shape expression of the zero splicing double-aspheric surface when the front surface of the single CGH lens compensator in the zero compensation detection system is the binary optical surface 3, the zero splicing double-aspheric surface is of a rotationally symmetrical structure, and the maximum effective caliber is determined by the actual light transmission caliber of the interferometer standard mirror.
3. 3. The method for characterizing a spliced aspheric surface based on a zero compensation detection light path of a CGH lens according to claim 1, wherein when the diffraction surface of the single CGH lens compensator faces towards a zero spliced double aspheric surface, the detection light is emitted in parallel by an interferometer standard mirror, and the radial coordinate of the surface of the binary optical surface 3 is divided into the inner part And outside Region, and at the inner and outer connecting edges Corresponds to at the refracting surface to Point that the outgoing light of the detection light after passing through the refraction surface intersects with the surface of the internal region CGH The point at which the current is to be measured, After the light rays of the diffraction orders are emitted, the light rays are intersected with the aspheric surface A point, the incidence height of the detection light on the interferometer standard mirror is Is intersected with the front refraction surface Point that the outgoing light after passing through the refracting surface intersects with the external CGH surface The point at which the current is to be measured, After the light rays of the diffraction orders are emitted, the light rays are intersected with the aspheric surface A point, the incidence height of the detection light on the interferometer standard mirror is Is intersected with the front refraction surface Point (there are) Will be And As a parameter of the aspherical surface shape, In the caliber section of the interferometer standard mirror , Within the equation is a continuous variable, In the aperture range of the interferometer standard mirror The inside is a continuous variable; When each parameter in the zero compensation detection system is fixed, the light height is detected 、 Incident by 、 Point to point 、 The point light ranges are the same at the moment 、 The locus function formed by the points is a zero splicing double aspheric formula which is characterized when the rear surface of the single CGH lens compensator is a binary optical surface 3, and the parameter expression of the general form can be expressed as follows: ; ; Wherein the method comprises the steps of , ; According to the principle of aplanatism, when the radial coordinate of the diffraction surface is When in use, two detection light rays are selected, wherein one light ray is the center point of the refraction surface of the single CGH lens compensator The outgoing light rays are in the path: Wherein, the method comprises the steps of, The point is the center vertex of the back surface of the single CGH lens compensator, The point is the central vertex of the aspheric surface, and the corresponding optical path is ; The other ray is a parametric trace ray, i.e., off-axis ray, with the path: according to the parameter of the zero compensation detection system, determining that the corresponding optical path of the parameter tracking light is Wherein Is that Dots and dots The distance between the points is such that, Is used for refracting light Intersection point on optical axis Dots and dots The distance between the points is such that, Is used for refracting light Intersection on optical axis Dots and dots The distance between the points; According to the principle of aplanatism, there are Obtaining On points and internal aspheres The distance between the points is ; To be used for When the point is the origin of coordinates and the back surface of a single CGH lens compensator in the zero compensation detection system is a binary optical surface 3, the zero splice double-aspheric inner focus aspheric area is any point The trajectory equation of (2) is: ; Wherein the method comprises the steps of Refractive light for the back surface of a single CGH lens compensator Included angle with the optical axis, Refractive light for the back surface of a single CGH lens compensator Intersection with optical axis Point-to-single CGH lens compensator back surface vertex Is a distance of (2); by the same token, when the radial coordinate of the diffraction plane is In the time-course of which the first and second contact surfaces, On points and external aspheres The distance between the points is Wherein Is that Dots and dots The distance between the points is such that, Is used for refracting light Intersection point on optical axis Dots and dots The distance between the points is such that, Is used for refracting light Intersection on optical axis Dots and dots The distance between the points; To be used for When the point is the origin of coordinates and the back surface of a single CGH lens compensator in the zero compensation detection system is a binary optical surface 3, the zero splice double-aspheric external focus aspheric area is at any point The trajectory equation of (2) is: ; Wherein the method comprises the steps of Refractive light for the back surface of a single CGH lens compensator Included angle with the optical axis, Refractive light for the back surface of a single CGH lens compensator Intersection with optical axis Point-to-single CGH lens compensator back surface vertex Is a distance of (2); the said Dots and The track equation of the point is the surface shape expression of the zero splicing double-aspheric surface when the rear surface of the single CGH lens compensator in the zero compensation detection system is the binary optical surface 3, the zero splicing double-aspheric surface is of a rotationally symmetrical structure, and the maximum effective caliber is determined by the actual light transmission caliber of the interferometer standard mirror.
4. 4. The method for characterizing a spliced aspheric surface based on a CGH lens zero compensation detection light path according to claim 1, wherein the binary optical surface 4 supports a plurality of concentric radial regions, each region has independent radius, conic curve and polynomial aspheric surface and diffraction phase distribution, and when the phase function of the diffraction surface is the binary optical surface 4, only diffraction phases of the plurality of concentric radial regions are considered; number of regions Between 1 and 60, the number of phase terms being between 0 and 20, the diffraction plane surface being divided into zones, the first zone extending from the apex to the radial coordinate The second area is from Extends to And so on until the last region is traversed and the radial coordinates of the first region are greater than 0, each region then having to be greater than the previous region; Diffraction phase distribution with independent coefficients for all regions, regions The phase expression of (2) is: wherein Is the number of coefficients of the polynomial, Is the normalized radial aperture of the lens, Is that A kind of electronic device The coefficient of the power of the two, Is the diffraction order; for the phase offset between the two regions, the expression is: Calculation of In the time-course of which the first and second contact surfaces, To be 0, when the phase difference of the two regions at the boundary is an integral multiple of the wavelength, i In which If the imaging performance is any integer, the boundary in-phase condition of the two areas is satisfied, and the optimal imaging performance is obtained; to satisfy the problem of boundary continuity, calculate the boundary of every two regions And the sum of squares thereof, and sets the sum of squares thereof to 0.
5. 5. The method for characterizing a spliced aspheric surface based on a zero compensation detection light path of a CGH lens as defined in claim 4, wherein when the diffraction surface of the single CGH lens compensator faces to an incident plane wave, the detection light is emitted in parallel by an interferometer standard mirror, and the radial coordinate of the surface of the binary optical surface 4 is divided into The areas are marked as Detecting that the light parallel wave intersects with the CGH surface The point at which the current is to be measured, After the light rays of the diffraction orders are emitted, the light rays are intersected with the rear refraction surface Point, after refraction by the back surface, intersects with the aspheric surface Setting the incident height of light on the interferometer standard mirror as The areas on the refractive surface are divided into areas corresponding to the areas of the diffraction surface due to the division of the binary optical surface 4, and the incident heights are respectively expressed as Wherein Will (i) be As a parameter of the aspherical surface shape, Interferometer standard mirror caliber interval , Within is a continuous variable; When each parameter in the zero compensation detection system is fixed, the light height is detected Incident by Point to point The point light ranges are the same at the moment The locus function formed by the points is a zero splicing multi-aspheric formula which is characterized when the front surface of the single CGH lens compensator is a binary optical surface 4, and the parameter expression of the general form can be expressed as follows: ; Wherein the method comprises the steps of ; According to the principle of aplanatism, when the radial coordinate of the diffraction surface is When in use, two detection light rays are selected, wherein one light ray is the center point of the diffraction surface of the single CGH lens compensator The outgoing light rays are in the path: Wherein, the method comprises the steps of, The point is the center vertex of the back surface of the single CGH lens compensator, The point is the central vertex of the aspheric surface, and the corresponding optical path is ; The other ray is a parametric trace ray, i.e., off-axis ray, with the path: according to the parameter of the zero compensation detection system, determining that the corresponding optical path of the parameter tracking light is Wherein Is that Dots and dots The distance between the points is such that, Is used for refracting light Intersection point on optical axis Dots and dots The distance between the points is such that, Is used for refracting light Intersection on optical axis Dots and dots The distance between the points; According to the principle of aplanatism, there are Obtaining On points and internal aspheres The distance between the points is ; To be used for When the point is the origin of coordinates and the front surface of a single CGH lens compensator in the zero compensation detection system is a binary optical surface 4, zero splicing is performed on any point of the aspheric surface area inside the multiple aspheric surfaces The trajectory equation of (a) is that the surface shape expression of the zero splice multiple aspheric surfaces is: ; Wherein the method comprises the steps of Refractive light for the back surface of a single CGH lens compensator Included angle with the optical axis, Refractive light for the back surface of a single CGH lens compensator Intersection with optical axis Point-to-single CGH lens compensator back surface vertex The zero position spliced multi-aspheric surface is of a rotationally symmetrical structure, and the maximum effective caliber is determined by the actual light-transmitting caliber of the interferometer standard mirror.
6. 6. The method for characterizing a spliced aspheric surface based on a zero compensation detection light path of a CGH lens as defined in claim 4, wherein when the diffraction surface of the single CGH lens compensator faces to a zero spliced multi-aspheric surface, the detection light is emitted in parallel by an interferometer standard mirror and intersects with a front refraction surface The point is divided into radial coordinates of the surface of the binary optical surface 4 The areas are marked as The emergent light of the refraction surface corresponds to Point, the emergent ray passing through the refracting surface intersects with the CGH surface The point at which the current is to be measured, After the light rays of the diffraction orders are emitted, the light rays are intersected with the aspheric surface Setting the incident height of light on the interferometer standard mirror as The areas on the refractive surface are divided into areas corresponding to the areas of the diffraction surface due to the division of the binary optical surface 4, and the incident heights are respectively expressed as Wherein Will (i) be As a parameter of the aspherical surface, Interferometer standard mirror caliber interval , Within is a continuous variable; When each parameter in the zero compensation detection system is fixed, the light height is detected Incident by Point to point The point light ranges are the same at the moment The locus function formed by the points is a zero splicing multi-aspheric formula which is characterized when the rear surface of the single CGH lens compensator is a binary optical surface 4, and the parameter expression of the general form can be expressed as follows: ; Wherein the method comprises the steps of ; According to the principle of aplanatism, when the radial coordinate of the diffraction surface is When in use, two detection light rays are selected, wherein one light ray is the center point of the refraction surface of the single CGH lens compensator The outgoing light rays are in the path: Wherein, the method comprises the steps of, The point is the center vertex of the back surface of the single CGH lens compensator, The point is the central vertex of the aspheric surface, and the corresponding optical path is ; The other ray is a parametric trace ray, i.e., off-axis ray, with the path: according to the parameter of the zero compensation detection system, determining that the corresponding optical path of the parameter tracking light is Wherein Is that Dots and dots The distance between the points is such that, Is used for refracting light Intersection point on optical axis Dots and dots The distance between the points is such that, Is used for refracting light Intersection on optical axis Dots and dots The distance between the points; According to the principle of aplanatism, there are Obtaining On points and internal aspheres The distance between the points is ; To be used for When the point is the origin of coordinates and the rear surface of a single CGH lens compensator in the zero compensation detection system is a binary optical surface 4, zero splicing is performed on any point of the aspheric surface area inside the multiple aspheric surfaces The trajectory equation of (a) is that the surface shape expression of the zero splice multiple aspheric surfaces is: ; Wherein the method comprises the steps of Refractive light for the back surface of a single CGH lens compensator Included angle with the optical axis, Refractive light for the back surface of a single CGH lens compensator Intersection with optical axis Point-to-single CGH lens compensator back surface vertex The zero position spliced multi-aspheric surface is of a rotationally symmetrical structure, and the maximum effective caliber is determined by the actual light-transmitting caliber of the interferometer standard mirror.

Description

Spliced aspheric surface characterization method based on CGH lens zero compensation detection light path Technical Field The invention relates to the technical field of optical aspheric surfaces, in particular to a spliced aspheric surface characterization method based on a CGH lens zero compensation detection light path. Background Optical aspheres are an important optical surface shape that allows for more precise control of the ray direction and focusing effects than spherical lenses, thus achieving higher optical performance and less imaging distortion, and thus find application in a wide range of fields. However, for some special application scenes, the aspheric surface has limited control capability for optimizing the surface shape, and the optimization efficiency is not high. The spliced aspheric surface is formed by splicing each section of curved surface based on the aspheric surface and the annular surface. Dividing a complete curved surface into a plurality of sub-curved surfaces, describing each sub-curved surface by using the existing optical curved surface, and controlling adjacent sub-curved surfaces to be connected smoothly, so as to ensure that the plurality of sub-curved surfaces still form a complete curved surface in mathematical description. In the process of stitching aspheric surface detection, a computational hologram (Computer-GENERATED HOLOGRAM, CGH) can flexibly diffract wave fronts with arbitrary shapes, which is equivalent to a phase compensator to replace a complex refractive lens combination. The zero compensation test method is the method with highest surface shape measurement precision of the optical element at present, and the gradient compensation is carried out on the measured piece by introducing various compensators so as to achieve the purpose of zero interference measurement. The CGH device is a binary optical diffraction element that can generate free wave fronts of arbitrary shape, making it well suited for null interferometry of optically spliced aspheres. However, the CGH method is a one-to-one detection method, and the design of the compensator is closely related to the shape of the spliced aspheric surface. Because the spliced aspheric lens is a common part of the system optical path and the zero compensation detection optical path, and in actual production, the system optical path design and the zero compensation detection optical path design are sequentially and unidirectionally carried out, the zero compensation detection optical path design cannot provide feedback for the system optical path design, and the zero compensation detection optical path cannot be optimized by effectively utilizing the latitude of the system optical path, so that the minimum deviation of the spliced aspheric surface shape can cause the compensator structure to become very complex, and the zero compensation method cannot be feasible. Disclosure of Invention Therefore, the invention aims to solve the technical problems that in the prior art, because the design of the spliced aspheric surface is prior to processing and detection, when the zero compensation method is used for detection, the detection cannot provide feedback for the design, and the tolerance of the system optical path structure cannot be effectively utilized to finely adjust the detection scheme, so that the detection scheme is very complex under partial conditions, and the detection precision is reduced. In order to solve the technical problems, the invention provides a spliced aspheric surface characterization method based on a CGH lens zero compensation detection light path, which comprises the following steps: In a zero compensation detection system with an interferometer incident wavefront as a plane wave and a single CGH lens as a compensator, the light passing caliber of a standard lens of the interferometer is D, the wavelength of detection light is lambda, the phase of a diffraction surface of the single CGH lens compensator is phi, the diffraction order is M, the radius of curvature of a refraction surface is r, the thickness of the center of the single CGH lens compensator is D, the refractive index of a single CGH lens compensator material is n, and the distance between the single CGH lens compensator and an aspheric surface is L; Constructing a zero compensation detection light path according to the characterization parameters of the self-defined zero splicing aspheric surface, wherein the interferometer standard mirror detects parallel incidence of light rays, different heights and different diffraction orders correspond to different points on the aspheric surface, and different diffraction surface directions correspond to different points of the zero splicing aspheric surface respectively; In the zero compensation detection system model, a single CGH lens compensator takes a plane binary optical surface as a reference, a phase function of a diffraction surface is a rotationally symmetrical binary optical