CN105423948A - Splicing-interference-detection aspheric surface shape apparatus using distorting lens and method thereof - Google Patents

Abstract

A splicing-interference-detection aspheric surface shape apparatus using a distorting lens and a method thereof belong to the optical detection technology field. In the invention, an interference detection system, a distorting lens compensation system, a mechanical adjusting mechanism and a computer data processing module are included. The method comprises the following steps of step1, constructing a splicing interference detection apparatus using the distorting lens; step2, dividing a subaperture; step3, removing to a position of the subaperture to be detected and adjusting a distorting lens surface shape or a refractive index according to modeling and interference fringes; step4, carrying out subaperture interferogram acquisition processing; step5, carrying out subaperture backhaul error correction; and step6, carrying out full aperture surface shape splicing. In the invention, the distorting lens and the subaperture splicing interference detection method are combined; the subaperture number needed by full aperture coverage can be effectively reduced and effective areas of each subaperture and an overlapping region are increased; a problem that the overlapping region is small so that splicing precision is influenced is solved.

Description

The stitching interferometer of distorting lens is adopted to detect the device and method of aspheric surface

Technical field

The invention belongs to technical field of optical detection, be specifically related to a kind of device and method adopting the stitching interferometer of distorting lens to detect aspheric surface.

Background technology

Interfere detection technique to be conventional surface testing technology, it is tested surface and the relative detection of reference surface.Reference surface is all generally plane or sphere, and there will not be more interference fringe when the plane after detecting polishing with them and sphere, and detect aspheric surface with spherical reference face, when aspheric slope is larger, interference fringe density is also more.When interference fringe density exceedes the nyquist frequency of interferometer detector, interference fringe cannot be detected device and differentiate, and causes aspheric surface cannot be measured.For the aspheric surface that slope is larger, adopt sub-aperture stitching interferometer detection method, aspheric surface larger for slope is divided into multiple small-bore sub-aperture, makes the interference fringe in each sub-aperture to be detected resolution.

But when aspheric surface bore slope is excessive, the area that each sub-aperture from center to edge can be detected is more and more less, now need more sub-aperture could cover whole aspheric surface, reduce detection efficiency, add machine error, detection time and data processing amount etc.

Summary of the invention

The object of the invention is to propose a kind of device and method adopting the stitching interferometer of distorting lens to detect aspheric surface, solve the problem that detection efficiency is low, machine error is large, detection time is long and data processing amount is large that prior art exists.In conjunction with distorting lens technology and annular sub-aperture stitching interferometer detection method, effectively can reduce and cover unified required sub-aperture number, increase each sub-aperture useful area, solve and the difficult problem of impact splicing precision little due to overlay region.

For achieving the above object, the device of the stitching interferometer detection aspheric surface of employing distorting lens of the present invention comprises distorting lens bucking-out system, interferes detection system, mechanical adjusting mechanism and computer digital animation module;

Described computer digital animation module comprises distorting lens control module, multidimensional adjusting table control module, interferogram sampling processing unit, hysterisis error correcting unit and sub-aperture stitching algorithm unit;

Aspheric surface to be detected is fixed on described mechanical adjusting mechanism, and described interference detection system compensates the optical path difference with aspheric surface reflected light to be detected by distorting lens bucking-out system, and described interferogram sampling processing unit is connected with the detector of interfering in detection system;

Described interferogram sampling processing unit is connected with described distorting lens control module and hysterisis error correcting unit, distorting lens control module carries out close-loop feedback according to interferogram to the adjustment of distorting lens, control multidimensional adjusting table control module and close-loop feedback control is carried out to the motion of multidimensional adjusting table, each sub-aperture interferogram that detector collects is through described interferogram sampling processing unit processes, obtain each sub-aperture and return Wave-front phase, each sub-aperture returns Wave-front phase and obtains each sub-aperture diametric plane shape information through hysterisis error correcting unit, each sub-aperture diametric plane shape information obtains unified shape information through the process of sub-aperture stitching algorithm unit.

Described mechanical adjusting mechanism comprises clamping device and multidimensional adjusting table, and described aspheric surface to be detected is fixed on described multidimensional adjusting table by clamping device.

Described interference detection system is Tai Man-Green's type interferometer or Feisuo type interferometer.

The method adopting the stitching interferometer of distorting lens to detect aspheric surface comprises the following steps:

Step one: build the device adopting the stitching interferometer of distorting lens to detect aspheric surface;

Step 2: system modelling, divides sub-aperture, and makes the reference paper of each sub-aperture, be specially:

1) sub-aperture planning is carried out according to the bore of the radius-of-curvature of aspheric best-fit ball to be detected, best-fit ball, the radius-of-curvature with reference to sphere, the bore with reference to sphere and sub-aperture overlapping region;

2) interfere the parameter of the concrete device of detection system according to aspheric surface in pick-up unit, in optical design software, interfere detection system to carry out modeling to aspheric surface, obtain system model;

3) according to step 1) planning carried out sub-aperture is in step 2) in carry out sub-aperture division in the system model that obtains;

4) detect the known high precision sphere of face shape error ε by interferometer, obtain the measured value W of high precision spherical surface shape _sphere-test; In Zemax optical design software, faced by simulate ideal reference sphere, high precision sphere detects, and high precision sphere surface figure accuracy testing result is W _sphere-ideal, obtain interferometer system error E by formula (1) _irigging error E is manufactured with collimating mirror _f:

E _I+E _F＝W _sphere-teat-W _sphere-ideal-2ε(1)

5) by any one sub-aperture diametric plane shape of system model analog detection desired aspheric W _{asphere-ideal}; By any one sub-aperture diametric plane shape W _{asphere-ideal}depart from the error caused with reference to sphere as aspheric surface, obtain the fixed phase W of sub-aperture according to formula (2) _reference:

W _reference＝W _{asphere-ideal}+W _sphere-test-W _sphere-ideal-2ε(2)；

Step 3: divide according to sub-aperture and show that the amount of exercise detecting each axle of multidimensional adjusting table needed for each sub-aperture is accurately located aspheric surface, and adjust distoring mirror shape or refractive index, until interference fringe picture meets testing requirement according to system model and interference fringe;

Step 4: gather each sub-aperture interferogram by interferogram sampling processing unit, utilizes unwrapping algorithm to carry out interferogram phase demodulating, obtains each sub-aperture Wave-front phase W that in testing, detector receives _asphere-test;

Step 5: calculating each sub-aperture diametric plane shape ε according to formula (3) _asphere:

${\mathrm{\ϵ}}_{asphere}=\frac{1}{2}\[W_{asphere-test}-W_{reference}\]$ (3)

Wherein: W _asphere-testfor sub-aperture Wave-front phase

W _referencefor the fixed phase of sub-aperture;

Step 6: according to each sub-aperture diametric plane shape ε obtained in step 5 _asphere, reduce the impact of machine error on splicing result by stitching algorithm, the most each sub-aperture diametric plane graphic data splicing, draws unified shape.

Described interference detection system is Tai Man-Green's type interferometer or Feisuo type interferometer.

Described in step 3 according to system model and interference fringe adjustment distoring mirror shape or refractive index, until the concrete steps that interference fringe picture meets testing requirement are:

1) detecting the Zelnick aberration at the detector place obtained according to emulation in optical design software, when interfering detection system to select Twyman Green Interferometer, the face shape of distorting lens being set to 1/2 of Zelnick aberration; When interfering detection system to select Feisuo interferometer, adopt the method for " inversion " to calculate the index distribution compensated needed for aspheric surface, the phase place needed for calculation compensation aspheric surface, P is any point in aspheric surface, cross P and do aspheric normal, hand over distorting lens rear surface to be M; Light PM, after distorting lens diffraction, hands over distorting lens front surface to be N, then to reflect last convergent point be F; Wherein the refractive index of distorting lens is ng, and the refractive index of surrounding air is na; Aspheric surface is d1 apart from the distance of distorting lens rear surface, and distorting lens thickness is the distance of d, F distance distorting lens front surface is d2;

According to Fermat principle, any point in aspheric surface be made all to converge to a F along the light of normal emergence, then have:

n _a|PM|+n _g|MN|+n _a|NF|＝n _ad ₁+n _gd+n _ad ₂

Distorting lens refractive index ng is calculated by formula (4):

$n_g=\frac{n_a{d}_1+n_{g}d+n_a{d}_{2-}{n}_a\left|NF\right|-n_a\left|PM\right|}{\left|MN\right|}---\left(4\right)$

2) by interfering detection system to detect sub-aperture, interference fringe picture is obtained;

3) according to step 2) in the interference fringe picture that obtains distorting lens carry out step 1) in feedback regulation, until interference fringe picture meets testing requirement, distorting lens has regulated.

Stitching algorithm described in step 6 is specially:

1) according to sub-aperture diametric plane shape after formula (5) calculating introducing compensation rate

$E_{{\mathrm{asphere}}_i}={\mathrm{\ϵ}}_{{\mathrm{asphere}}_i}+\underset{k=1}{\overset{L}{\Σ}}{F}_{ik}{f}_k(x,y),k=1,2...L---\left(5\right)$

Wherein: f _kthe compensation factor that (x, y) is sub-aperture;

L is the number compensating factor;

for the face shape of i-th sub-aperture that step 5 obtains;

F _ikfor sub-aperture compensates the penalty coefficient of factor, obtained the penalty coefficient F of each sub-aperture by the least square method shown in formula (6) _ik;

$\min =\underset{i=\mathrm{1...}N-1}{\mathrm{\Σ}}\underset{j=\mathrm{0...}N-1}{\overset{j\∩i}{\mathrm{\Σ}}}{\left(\right({\mathrm{\ϵ}}_{{\mathrm{asphere}}_i}\left(x,y\right)+\underset{k=1}{\overset{L}{\mathrm{\Σ}}}{F}_{ik}{f}_k\left(x,y\right))-({\mathrm{\ϵ}}_{{\mathrm{asphere}}_j}\left(x,y\right)+\underset{k=1}{\overset{L}{\mathrm{\Σ}}}{F}_{jk}{f}_k\left(x,y\right)\left)\right)}^2---\left(6\right)$

Wherein, N is the number of sub-aperture;

Sub-aperture counts from zero, i.e. sub-aperture centered by the 0th sub-aperture;

representing only has the jth of an overlapping region sub-aperture to calculate to i-th sub-aperture;

2) according to step 1) each sub-aperture diametric plane shape of obtaining splicing obtains unified shape, is about to all be added, the face shape of overlapping region gets the weighted mean value of each sub-aperture data, and weight is relevant to the accuracy of measurement data.

Described optical design software is Zemax software.

Beneficial effect of the present invention is: the present invention is in conjunction with distorting lens and sub-aperture stitching interferometer detection method, distorting lens is utilized to produce the different sub-aperture region of non-spherical wavefront coupling tested surface, make to detect unified required sub-aperture number to greatly reduce, add sub-aperture area, thus add the overlay region of adjacent sub-aperture, reduce the accumulation of detection time, machine error, improve the efficiency and precision that detect.Efficiently solve the problem that the splicing precision that causes because sub-aperture area is too low is low, add splicing efficiency simultaneously.

Accompanying drawing explanation

Fig. 1 is that the stitching interferometer of employing distorting lens of the present invention detects in the device of aspheric surface structural representation when adopting Tai Man-Green's type interferometer;

Fig. 2 is that the stitching interferometer of employing distorting lens of the present invention detects in the device of aspheric surface structural representation when adopting Feisuo type interferometer;

Fig. 3 is the method overhaul flow chart of the stitching interferometer detection aspheric surface of employing distorting lens of the present invention;

Fig. 4 is the method sub-aperture Structure Planning schematic diagram of the stitching interferometer detection aspheric surface of employing distorting lens of the present invention;

Fig. 5 is that the stitching interferometer of employing distorting lens of the present invention detects distoring mirror shape or refractive index adjust structure schematic diagram in the method for aspheric surface;

Wherein: 1, frequency stabilized laser, 2, collimating and beam expanding system, 3, Amici prism, 4, distorting lens, 5, imaging lens, 6, detector, 7, converging lenses group, 8, aspheric surface, 9, clamping device, 10, computing machine, 11, multidimensional adjusting table, 12, distorting lens control module, 13, multidimensional adjusting table control module, 14, interferogram sampling processing unit, 15, catoptron, 16, standard mirror, 17, reference surface.

Embodiment

Below in conjunction with accompanying drawing, embodiments of the present invention are described further.

The device of the stitching interferometer detection aspheric surface of employing distorting lens of the present invention comprises distorting lens bucking-out system, interferes detection system, mechanical adjusting mechanism and computer digital animation module;

Described computer digital animation module comprises distorting lens control module 12, multidimensional adjusting table control module 13, interferogram sampling processing unit 14, hysterisis error correcting unit and sub-aperture stitching algorithm unit;

Aspheric surface 8 to be detected is fixed on described mechanical adjusting mechanism, described interference detection system compensates the optical path difference with aspheric surface 8 reflected light to be detected by distorting lens bucking-out system, and described interferogram sampling processing unit 14 is connected with the detector 6 of interfering in detection system;

Described interferogram sampling processing unit 14 is connected with described distorting lens control module 12 and hysterisis error correcting unit, distorting lens control module 12 carries out close-loop feedback according to interferogram to the adjustment of distorting lens 4, close-loop feedback control is carried out in the motion controlling multidimensional adjusting table control module 13 pairs of multidimensional adjusting tables 11, each sub-aperture interferogram that detector 6 collects processes through described interferogram sampling processing unit 14, obtain each sub-aperture and return Wave-front phase, each sub-aperture returns Wave-front phase and obtains each sub-aperture diametric plane shape information through hysterisis error correcting unit, each sub-aperture diametric plane shape information obtains unified shape information through the process of sub-aperture stitching algorithm unit.

Described mechanical adjusting mechanism comprises clamping device 9 and multidimensional adjusting table 11, and described aspheric surface 8 to be detected is fixed on described multidimensional adjusting table 11 by clamping device 9.

See accompanying drawing 1, described interference detection system is Tai Man-Green's type interferometer, and the light pencil of frequency stabilized laser 1 outgoing is expanded as angle pencil of ray directional light through collimating and beam expanding system 2, and angle pencil of ray directional light forward direction is divided into two-way to Amici prism 3 place; Wherein a road returns as reference ripple through Amici prism 3 reflections propagate to distorting lens 4 Hou Yuan road; Another road is first assembled and is dispersed afterwards after Amici prism 3 transmission forward direction to converging lenses group 7, and diverging light again after converging lenses group 7, is formed and detects ripple after aspheric surface 8 reflects.Detector 6 place is imaged in through imaging lens 5 after reference wave and detection wave interference.

See accompanying drawing 2, described interference detection system is Feisuo type interferometer, the light pencil of the frequency stabilized laser 1 outgoing light forward direction after collimating and beam expanding system 2 is to Amici prism 3 place, Amici prism 3 reflections propagate is to catoptron 15, through standard mirror 16, a part is as reference ripple after reference surface 17 reflects, and another part transmission forward direction is to distorting lens 4, after aspheric surface 8 reflects again after distorting lens 4, formed and detect ripple.Detector 6 place is imaged in through imaging lens 5 after reference wave and detection wave interference.

The need of work distorting lens drive system of distorting lens bucking-out system, interference detection system, computer control system complete jointly.By the interference fringe picture of interferometer measurement, close-loop feedback control is carried out to distorting lens 4.Distorting lens bucking-out system mainly comprises the distorting lens control module 12 in distorting lens 4 and computer digital animation module, draw required distorting lens 4 deflection according to computing machine 10 simulation results or interference detection system measurement result, by computing machine 10 controlling distortion mirror driver, distorting lens 4 is out of shape.

Mechanical adjusting mechanism comprises the multidimensional adjusting table control module 13 in the locating devices such as multidimensional adjusting table 11, grating scale and computer digital animation module.Aspheric surface 8 is fixed on clamping device 9, and clamping device 9 is fixed on multidimensional adjusting table 11.The mirror pose to be measured providing and detect needed for each sub-aperture is planned by sub-aperture, computing machine 10 can drive multidimensional adjusting table 11 to make clamping device 9 along the translation of x, y, z axle, x, y-axis tilt, and rotate around z-axis, the position of multi-dimensional movement can be carried out close-loop feedback by locating devices such as all directions grating scales and be controlled.

The image that detector 6 collects by interferogram sampling processing unit 14 is after machine 10 processes as calculated, and Output rusults, to hysterisis error correcting unit, then obtains unified shape information through sub-aperture stitching unit.

See accompanying drawing 3, the method adopting the stitching interferometer of distorting lens to detect aspheric surface comprises the following steps:

Step one: build the device adopting the stitching interferometer of distorting lens to detect aspheric surface;

Step 2: system modelling, divides sub-aperture, and makes the reference paper of each sub-aperture, be specially:

1) sub-aperture planning is carried out according to the bore of the radius-of-curvature of the best-fit ball of aspheric surface 8 to be detected, best-fit ball, the radius-of-curvature with reference to sphere, the bore with reference to sphere and sub-aperture overlapping region;

See accompanying drawing 4, such as aspheric surface 8 best-fit ball, reference sphere, overlapping region are as following table:

Sub-aperture distribution is as follows:

2) interfere the parameter of the concrete device of detection system according to aspheric surface in pick-up unit 8, in optical design software, interfere detection system to carry out modeling to aspheric surface 8, obtain system model;

Detection system is interfered for Tai Man-Green's type, the parameter of described concrete device comprises: the optical maser wavelength of frequency stabilized laser 1 outgoing, the clear aperture of collimating and beam expanding system 2 and enlargement factor, the parameter of Amici prism 3, the bore of distorting lens 4, the bore of imaging lens 5 and surface curvature radius and thickness, the nominal face shape equation of tested aspheric surface 8 and bore;

3) according to step 1) planning carried out sub-aperture is in step 2) in carry out sub-aperture division in the system model that obtains;

4) detect the known high precision sphere of face shape error ε by interferometer, obtain the measured value W of high precision spherical surface shape _sphere-test; In Zemax optical design software, faced by simulate ideal reference sphere, high precision sphere detects, and high precision sphere surface figure accuracy testing result is W _sphere-ideal, obtain interferometer system error E by formula (1) _irigging error E is manufactured with collimating mirror _f:

E _I+E _F＝W _sphere-test-W _sphere-ideal-2ε(1)

5) by any one sub-aperture diametric plane shape of system model analog detection desired aspheric 8 W _{asphere-ideal}; By any one sub-aperture diametric plane shape W _{asphere-ideal}depart from the error caused with reference to sphere as aspheric surface 8, obtain the fixed phase W of sub-aperture according to formula (2) _reference:

W _reference＝W _{asphere-ideal}+W _sphere-test-W _sphere-ideal-2ε(2)；

Step 3: divide according to sub-aperture and show that the amount of exercise detecting each axle of multidimensional adjusting table 11 needed for each sub-aperture is accurately located aspheric surface 8, and adjust distorting lens 4 shapes or refractive index, until interference fringe picture meets testing requirement according to system model and interference fringe;

Step 4: gather each sub-aperture interferogram by interferogram sampling processing unit 14, utilizes unwrapping algorithm to carry out interferogram phase demodulating, obtains each sub-aperture Wave-front phase W that in testing, detector 6 receives _asphere-test;

Step 5: calculating each sub-aperture diametric plane shape ε according to formula (3) _asphere:

${\mathrm{\ϵ}}_{asphere}=\frac{1}{2}\[W_{asphere-test}-W_{reference}\]---\left(3\right)$

Wherein: W _asphere-testfor sub-aperture Wave-front phase

W _referencefor the fixed phase of sub-aperture;

Step 6: according to each sub-aperture diametric plane shape ε obtained in step 5 _asphere, reduce the impact of machine error on splicing result by stitching algorithm, the most each sub-aperture diametric plane graphic data splicing, draws unified shape.

Described interference detection system is Tai Man-Green's type interferometer or Feisuo type interferometer.

Described in step 3 according to system model and interference fringe adjustment distorting lens 4 shapes or refractive index, until the concrete steps that interference fringe picture meets testing requirement are:

1) detecting the Zelnick aberration at detector 6 place obtained according to emulation in optical design software, when interfering detection system to select Twyman Green Interferometer, the face shape of distorting lens 4 being set to 1/2 of Zelnick aberration; When interfering detection system to select Feisuo interferometer, the method of " inversion " is adopted to calculate the index distribution compensated needed for aspheric surface 8, phase place needed for calculation compensation aspheric surface 8, see accompanying drawing 5, P is any point in aspheric surface 8, cross the normal that P does aspheric surface 8, hand over distorting lens 4 rear surface to be M; Light PM, after distorting lens 4 diffraction, hands over distorting lens 4 front surface to be N, then to reflect last convergent point be F; Wherein the refractive index of distorting lens 4 is n _g, the refractive index of surrounding air is n _a; Aspheric surface 8 is d apart from the distance of distorting lens 4 rear surface ₁, distorting lens 4 thickness is the distance of d, F distance distorting lens 4 front surface is d ₂;

According to Fermat principle, any point in aspheric surface 8 be made all to converge to a F along the light of normal emergence, then have:

n _a|PM|+n _g|MN|+n _a|NF|＝n _ad ₁+n _gd+n _ad ₂

Distorting lens 4 refractive index n is calculated by formula (4) _g:

$n_g=\frac{n_a{d}_1+n_{g}d+n_a{d}_{2-}{n}_a\left|NF\right|-n_a\left|PM\right|}{\left|MN\right|}---\left(4\right)$

2) by interfering detection system to detect sub-aperture, interference fringe picture is obtained;

3) according to step 2) in the interference fringe picture that obtains distorting lens 4 carry out step 1) in feedback regulation, until interference fringe picture meets testing requirement, distorting lens 4 has regulated.

Stitching algorithm described in step 6 is specially:

1) according to sub-aperture diametric plane shape after formula (5) calculating introducing compensation rate

$E_{{\mathrm{asphere}}_i}={\mathrm{\ϵ}}_{{\mathrm{asphere}}_i}+\underset{k=1}{\overset{L}{\Σ}}{F}_{ik}{f}_k(x,y),k=1,2...L---\left(5\right)$

Wherein: f _kthe compensation factor that (x, y) is sub-aperture;

L is the number compensating factor;

for the face shape of i-th sub-aperture that step 5 obtains;

F _ikfor sub-aperture compensates the penalty coefficient of factor, obtain the penalty coefficient F of each sub-aperture by the such as least square method shown in formula (6) _ik;

$\min =\underset{i=\mathrm{1...}N-1}{\mathrm{\Σ}}\underset{j=\mathrm{0...}N-1}{\overset{j\∩i}{\mathrm{\Σ}}}{\left(\right({\mathrm{\ϵ}}_{{\mathrm{asphere}}_i}\left(x,y\right)+\underset{k=1}{\overset{L}{\mathrm{\Σ}}}{F}_{ik}{f}_k\left(x,y\right))-({\mathrm{\ϵ}}_{{\mathrm{asphere}}_j}\left(x,y\right)+\underset{k=1}{\overset{L}{\mathrm{\Σ}}}{F}_{jk}{f}_k\left(x,y\right)\left)\right)}^2---\left(6\right)$

Wherein, N is the number of sub-aperture;

Sub-aperture counts from zero, i.e. sub-aperture centered by the 0th sub-aperture;

representing only has the jth of an overlapping region sub-aperture to calculate to i-th sub-aperture;

2) according to step 1) in each sub-aperture diametric plane shape of obtaining splicing obtains unified shape, by used be added, the face shape of overlapping region gets the weighted mean value of each sub-aperture data, and weight is relevant to the accuracy of measurement data.

Described optical design software is Zemax software, is the optical design software developed by RadiantZemax company of the U.S..

Claims (8)

1. adopt the stitching interferometer of distorting lens to detect the device of aspheric surface, it is characterized in that, comprise distorting lens bucking-out system, interfere detection system, mechanical adjusting mechanism and computer digital animation module;

Described computer digital animation module comprises distorting lens control module (12), multidimensional adjusting table control module (13), interferogram sampling processing unit (14), hysterisis error correcting unit and sub-aperture stitching algorithm unit;

Aspheric surface to be detected (8) is fixed on described mechanical adjusting mechanism, described interference detection system compensates the optical path difference with aspheric surface to be detected (8) reflected light by distorting lens bucking-out system, and described interferogram sampling processing unit (14) is connected with the detector (6) of interfering in detection system;

Described interferogram sampling processing unit (14) is connected with described distorting lens control module (12) and hysterisis error correcting unit, distorting lens control module (12) carries out close-loop feedback according to the adjustment of interferogram to distorting lens (4), control multidimensional adjusting table control module (13) motion to multidimensional adjusting table (11) and carry out close-loop feedback control, each sub-aperture interferogram that detector (6) collects processes through described interferogram sampling processing unit (14), obtain each sub-aperture and return Wave-front phase, each sub-aperture returns Wave-front phase and obtains each sub-aperture diametric plane shape information through hysterisis error correcting unit, each sub-aperture diametric plane shape information obtains unified shape information through the process of sub-aperture stitching algorithm unit.

2. the stitching interferometer of employing distorting lens according to claim 1 detects the device of aspheric surface, it is characterized in that, described mechanical adjusting mechanism comprises clamping device (9) and multidimensional adjusting table (11), and described aspheric surface to be detected (8) is fixed on described multidimensional adjusting table (11) by clamping device (9).

3. the stitching interferometer of employing distorting lens according to claim 1 detects the device of aspheric surface, and it is characterized in that, described interference detection system is Tai Man-Green's type interferometer or Feisuo type interferometer.

4. the stitching interferometer of employing distorting lens according to claim 1 detects the detection method of the device of aspheric surface, it is characterized in that, comprises the following steps:

Step one: build the device adopting the stitching interferometer of distorting lens to detect aspheric surface;

Step 2: system modelling, divides sub-aperture, and makes the reference paper of each sub-aperture, be specially:

1) sub-aperture planning is carried out according to the bore of the radius-of-curvature of the best-fit ball of aspheric surface to be detected (8), best-fit ball, the radius-of-curvature with reference to sphere, the bore with reference to sphere and sub-aperture overlapping region;

2) interfere the parameter of the concrete device of detection system according to aspheric surface in pick-up unit, in optical design software, interfere detection system to carry out modeling to aspheric surface, obtain system model;

3) according to step 1) planning carried out sub-aperture is in step 2) in carry out sub-aperture division in the system model that obtains;

4) detect the known high precision sphere of face shape error ε by interferometer, obtain the measured value W of high precision spherical surface shape _sphere-test; In Zemax optical design software, faced by simulate ideal reference sphere, high precision sphere detects, and high precision sphere surface figure accuracy testing result is W _sphere-ideal, obtain interferometer system error E by formula (1) _irigging error E is manufactured with collimating mirror _f:

E _I+E _F＝W _sphere-test-W _sphere-ideal-2ε(1)

5) by any one sub-aperture diametric plane shape of system model analog detection desired aspheric (8) W _{asphere-ideal}; By any one sub-aperture diametric plane shape W _{asphere-ideal}depart from the error caused with reference to sphere as aspheric surface (8), obtain the fixed phase W of sub-aperture according to formula (2) _reference:

W _reference＝W _{asphere-ideal}+W _sphere-test-W _sphere-ideal-2ε(2)；

Step 3: divide according to sub-aperture and show that the amount of exercise detecting multidimensional adjusting table (11) each axle needed for each sub-aperture is accurately located aspheric surface (8), and adjust distorting lens (4) face shape or refractive index, until interference fringe picture meets testing requirement according to system model and interference fringe;

Step 4: gather each sub-aperture interferogram by interferogram sampling processing unit (14), utilizes unwrapping algorithm to carry out interferogram phase demodulating, obtains each sub-aperture Wave-front phase W that in testing, detector (6) receives _asphere-test;

Step 5: calculating each sub-aperture diametric plane shape ε according to formula (3) _asphere:

${\mathrm{\ϵ}}_{asphere}=\frac{1}{2}\[W_{asphere-test}-W_{reference}\]---\left(3\right)$

Wherein: W _asphere-testfor sub-aperture Wave-front phase

W _referencefor the fixed phase of sub-aperture;

Step 6: according to each sub-aperture diametric plane shape ε obtained in step 5 _asphere, reduce the impact of machine error on splicing result by stitching algorithm, the most each sub-aperture diametric plane graphic data splicing, draws unified shape.

5. the stitching interferometer of employing distorting lens according to claim 4 detects the device of aspheric surface, and it is characterized in that, described interference detection system is Tai Man-Green's type interferometer or Feisuo type interferometer.

6. the stitching interferometer of employing distorting lens according to claim 5 detects the device of aspheric surface, it is characterized in that, described in step 3 according to system model and interference fringe adjustment distorting lens (4) face shape or refractive index, until the concrete steps that interference fringe picture meets testing requirement are:

1) the Zelnick aberration at detector (6) place obtained is detected according to emulation in optical design software, when interfering detection system to select Twyman Green Interferometer, the face shape of distorting lens (4) is set to 1/2 of Zelnick aberration; When interfering detection system to select Feisuo interferometer, the method of " inversion " is adopted to calculate the index distribution compensated needed for aspheric surface (8), phase place needed for calculation compensation aspheric surface (8), P is any point in aspheric surface (8), cross the normal that P does aspheric surface (8), hand over distorting lens (4) rear surface to be M; Light PM, after distorting lens (4) diffraction, hand over distorting lens (4) front surface to be N, then to reflect last convergent point is F; Wherein the refractive index of distorting lens (4) is n _g, the refractive index of surrounding air is n _a; Aspheric surface (8) is d apart from the distance of distorting lens (4) rear surface ₁, distorting lens (4) thickness is the distance of d, F distance distorting lens (4) front surface is d ₂;

According to Fermat principle, the upper any point of aspheric surface (8) be made all to converge to a F along the light of normal emergence, then have:

n _a|PM|+n _g|MN|+n _a|NF|＝n _ad ₁+n _gd+n _ad ₂

Distorting lens (4) refractive index ng is calculated by formula (4):

$n_g=\frac{n_a{d}_1+n_{g}d+n_a{d}_2-n_a\left|NF\right|-n_a\left|PM\right|}{\left|MN\right|}---\left(4\right)$

2) by interfering detection system to detect sub-aperture, interference fringe picture is obtained;

3) according to step 2) in the interference fringe picture that obtains distorting lens (4) carry out step 1) in feedback regulation, until interference fringe picture meets testing requirement, distorting lens (4) has regulated.

7. the stitching interferometer of employing distorting lens according to claim 4 detects the device of aspheric surface, and it is characterized in that, the stitching algorithm described in step 6 is specially:

1) according to sub-aperture diametric plane shape after formula (5) calculating introducing compensation rate

${E_{asphere}}_i={{\mathrm{\ϵ}}_{asphere}}_i+\underset{k=1}{\overset{L}{\Σ}}{F}_{ik}{f}_k(x,y),k=1,2...L---\left(5\right)$

Wherein: f _kthe compensation factor that (x, y) is sub-aperture;

L is the number compensating factor;

for the face shape of i-th sub-aperture that step 5 obtains;

F _ikfor sub-aperture compensates the penalty coefficient of factor, obtain the penalty coefficient F of each sub-aperture by the such as least square method shown in (6) _ik;

$\min =\underset{i=1...N-1}{\Σ}\underset{j=0...N-1}{\overset{j\∩i}{\Σ}}{\left(\left({\mathrm{\ϵ}}_{{\mathrm{asphere}}_i}\left(x,y\right)+\underset{k=1}{\overset{L}{\Σ}}{F}_{ik}{f}_k\left(x,y\right)\right)-\left({\mathrm{\ϵ}}_{{\mathrm{asphere}}_j}\left(x,y\right)+\underset{k=1}{\overset{L}{\Σ}}{F}_{jk}{f}_k\left(x,y\right)\right)\right)}^2---\left(6\right)$

Wherein: N is the number of sub-aperture;

Sub-aperture counts from zero, i.e. sub-aperture centered by the 0th sub-aperture;

representing only has the jth of an overlapping region sub-aperture to calculate to i-th sub-aperture;

2) according to step 1) in each sub-aperture diametric plane shape of obtaining splicing obtains unified shape, by used be added, the face shape of overlapping region gets the weighted mean value of each sub-aperture data.

8. the stitching interferometer of employing distorting lens according to claim 4 detects the device of aspheric surface, and it is characterized in that, described optical design software is Zemax software.