CN108267094A - A kind of non-cylindrical interference splicing measuring systems and method based on rotation CGH - Google Patents
A kind of non-cylindrical interference splicing measuring systems and method based on rotation CGH Download PDFInfo
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- CN108267094A CN108267094A CN201810029231.3A CN201810029231A CN108267094A CN 108267094 A CN108267094 A CN 108267094A CN 201810029231 A CN201810029231 A CN 201810029231A CN 108267094 A CN108267094 A CN 108267094A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
- G01B11/2441—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures using interferometry
Abstract
The invention discloses a kind of non-cylindrical interference splicing measuring systems and method based on rotation CGH, which includes Feisuo flat interferometer, CGH cylindrical waves converter, non-cylindrical to be measured, non-cylindrical adjusting apparatus and precise rotating platform；The CGH cylindrical waves converter is mounted on precise rotating platform, and between Feisuo flat interferometer and non-cylindrical to be measured, and the precise rotating platform control CGH cylindrical waves converter rotation makes CGH cylindrical waves converter be rotated around the central axis of itself；The non-cylindrical to be measured is mounted in non-cylindrical adjusting apparatus；The optical axis of the Feisuo flat interferometer and the optical axis coincidence of CGH cylindrical wave converters, adjustment non-cylindrical adjusting apparatus make the best fit cylinder axis of non-cylindrical to be measured be overlapped with the focal axis line before the cylindrical wave of CGH cylindrical wave converter diffraction.In addition measuring method of the invention can significantly reduce the aberration of the off-axis sub-aperture of non-cylindrical, the accurate face shape error for measuring non-cylindrical optical element.
Description
Technical field
The present invention relates to optical precision measurement field, more particularly to a kind of non-cylindrical based on rotation CGH interferes splicing
Measuring system and method.
Background technology
Prismatic optical element (such as cylindrical lens) can change imaging size, such as can be one in one-dimensional square
Point hot spot is converted into a linear light spot or changes the height of picture in the case where not changing image width degree.This feature make its
It is indispensable in wavefront shaping, bar code scanning, the mating plate illumination optical systems such as microscope and line flying-spot microscope.Particularly
In strong laser system, Synchrotron Radiation, satellite guidance and navigation system, prismatic optical element plays key effect.
Non- cylindrical (such as cylindroid, parabolic cylinder) introduces more parameters than cylindrical surface in design, can correct picture
Difference improves image quality, and simplifies optical system, mitigates weight.Therefore, non-cylindrical optical element is expected to gradually substitute cylindrical lens
As the critical component in above-mentioned optical system.However, the Precision measurement of non-cylindrical optical component surface shape error is always optics
The still unsolved problem of fields of measurement, into its widely applied key factor of restriction.
At present, it is detected for the face shape error of non-cylindrical optical element, mainly using contact measurement method, such as three coordinates
Measuring machine and contourgraph.However, the sample rate of contact measurement method is low, it is difficult to obtain high-resolution measurement result, be used for
Characterize the unified face shape error distribution of non-cylindrical to be measured.In addition, contact type probe is easy to wear, measurement error can be generated,
Influence final measurement result.Interferometry technology, as the branch of optical three-dimensional measurement technology, due to it is untouchable,
The features such as whole audience, high-precision, high-resolution, makes its face shape error in precision component, optical element the fields such as detect and obtains
Increasingly extensive application.
Since the error (also known as non-cylindrical degree) that non-cylindrical deviates preferable cylindrical surface is too big, interfere far beyond cylinder
The vertical measurement range of system, the interference fringe resulted in is too close and can not parse.Cylinder can be interfered using compensator
The wave-front conversion that system is sent out into the matched non-cylindrical wavefront of tested non-cylindrical, so as to fulfill interference detection purpose,
But compensator carries out aberration balancing design both for tested surface, the i.e. possible needs if the parameter of tested surface slightly changes
Compensator is redesigned, causes the huge waste of time and financial cost.Such issues that interference splicing art is solves provides new
Thinking.Its basic principle is that testee is divided into the sub-aperture of several small sizes, has part between adjacent sub-aperture
Overlay region measures the situation face shape of object under test with small-bore interference system every time, by movement, rotation object under test or does
System is related to, measures whole sub-aperture face shape errors, is then obtained all sub-aperture measurement data entirely using stitching interferometry
Aperture face shape error.Document " J.Peng, H.Xu, Y.Yu, and M.Chen, " Stitching interferometry for
cylindrical optics with large angular aperture,”Meas.Sci.Technol.,vol.26,
No.2,25204, (2015) " and the basic thought that art is spliced in interference has been used for reference, obtain the complete of large-numerical aperture cylindrical optical element
Bore face shape error.However, the residual aberration for ensureing to return is needed to be no more than when detecting non-cylindrical using stitching interferometry
The vertical measurement range of interference system, to obtain analysable interference pattern.In order to meet this requirement, stitching interferometry inspection
The width of shortening sub-aperture is needed when surveying aspherical (or non-cylindrical), to reduce the residual aberration of return.This certainly will increase
Add the number of sub-aperture needed for measuring, cause time of measuring long, easily by environmental disturbances, the problems such as measurement accuracy is relatively low.
In order to reduce the number of sub-aperture needed for measurement, shorten time of measuring, can increase in off-axis sub-aperture measurement process
Add variable equalizer, compensate off-axis sub-aperture and the deviation of best fit cylinder or spherical surface.But with conventional zero compensation machine not
Together, it is only necessary to which the residual aberration of off-axis sub-aperture is reduced in the range of the vertical measurement of interferometer after compensation, compensator at this time
Referred to as near zero compensation machine.Further, since measuring the aberration difference compensated needed for the sub-aperture of different location, nearly zero-bit is needed to mend
The variable aberration of size can be generated by repaying device.
CN201210110946.4 patent documents disclose a kind of " nearly zero-bit benefit measured for aspheric aperture splicing
Repay device and surface shape measurement instrument and measuring method ", which proposes to form using the phase-plate that a pair is turned round in opposite directions variable near
Zero compensation machine, the phase function on phase-plate are Zernike multinomials composition, and two phase-plates can generate when rotating in opposite directions
The variable coma of size and spherical aberration can compensate for the part aberration of aspherical upper different location sub-aperture, splice so as to fulfill interference
Method detection steepness is aspherical.In addition, document " M.Tricard, A.Kulawiec and M.Bauer.Subaperture
stitching interferometry of high-departure aspheres by incorporating a
variable optical null.CIRP Annals-Manufacturing Technology,2010,59(1),547–
550. " propose a kind of sub-aperture stitching measuring method aspherical using variable nearly zero compensation machine realization steepness, this method
It using a pair of of Risley prisms, i.e., is made of the equal prism wedge of a pair of of angle, survey can be changed when two prisms turn round in opposite directions
The optical path difference of light path is tried, is introduced primarily into coma；And introduce picture during the whole inclined light shaft relative to interferometer of two prism wedges
It dissipates.By adjusting the two degree of freedom, the variable aberration of size can be generated, realizes the portion of aspherical upper different location sub-aperture
Divide aberration compensation, obtain analysable interference pattern.However, above two method needs additionally introduce variable zero in light path
Position compensator, certainly will increase measurement cost, increase the complexity of light path；In addition, above two method may be only available for revolution pair
Claim it is aspherical, be not suitable for non-cylindrical interference detection.
Invention content
It is an object of the invention to overcome shortcoming and deficiency of the prior art, provide a kind of based on the not rounded of rotation CGH
Cylinder interferes splicing measuring systems, is realized in the case where not increasing sub-aperture number needed for compensator and measurement non-to high steepness
The face shape error of cylindrical optics element measures.
Another object of the present invention is to the surveys with the above-mentioned non-cylindrical interference splicing measuring systems based on rotation CGH
Amount method.
In order to achieve the above object, the present invention adopts the following technical scheme that：
A kind of non-cylindrical based on rotation CGH interferes splicing measuring systems, including Feisuo flat interferometer, CGH cylinders
Wave converter, non-cylindrical to be measured, non-cylindrical adjusting apparatus and precise rotating platform；The Feisuo flat interferometer is flat for generating
Surface wave；Before the CGH cylindrical waves converter by plane wave for being diffracted into cylindrical wave, CGH cylindrical waves converter is mounted on precision
On turntable, and between Feisuo flat interferometer and non-cylindrical to be measured；The precise rotating platform is used to that CGH cylindrical waves to be controlled to turn
Parallel operation rotates, and CGH cylindrical waves converter is made to be rotated around the central axis of itself；The non-cylindrical to be measured is mounted on non-cylindrical
In the adjusting apparatus of face, adjustment mechanism of the non-cylindrical adjusting apparatus for a five degree of freedom, for adjusting non-cylindrical to be measured
The spatial position in face, including three rotations and two linear motions；The optical axis of the Feisuo flat interferometer turns with CGH cylindrical waves
The optical axis coincidence of parallel operation；Adjustment non-cylindrical adjusting apparatus makes the best fit cylinder axis of non-cylindrical to be measured and CGH cylinders
Focal axis line before the cylindrical wave of wave converter diffraction overlaps.
As preferred technical solution, the plane wave that the Feisuo flat interferometer is sent out is through CGH cylindrical wave converter shapes
Non- cylindrical to be measured is incident on before into cylindrical wave, again by CGH cylindrical wave converters after non-cylindrical to be measured reflection, most
It returns afterwards inside Feisuo flat interferometer with forming interference pattern with reference to the interference of light；Wherein, by changing CGH cylindrical wave converters
Rotation angle generates the variable non-cylindrical wavefront of size and shape.
As preferred technical solution, the measuring method of the non-cylindrical interference splicing measuring systems based on rotation CGH, packet
Include following steps：
S1 the F/ numbers of CGH cylindrical wave converters), are determined according to the theoretical face shape profile of non-cylindrical to be measured, divide sub-aperture
Diameter；The F is the back focal length of CGH cylindrical wave converters and the ratio of diaphragm diameter；
S2 the nominal amount of exercise of sub-aperture), is calculated according to the theoretical face shape profile of sub-aperture；
S3 non-cylindrical to be measured and the posture of CGH cylindrical wave converters), are adjusted according to the nominal amount of exercise of sub-aperture, obtained
Obtain analysable interference pattern；
S4), according to the amount of spin of CGH cylindrical wave converters, the nominal value of residual aberration is determined, so as to obtain sub-aperture
Face shape error data；The nominal value of the residual aberration is that theoretical face shape profile subtracts the converter generation of rotation CGH cylindrical waves
Remaining aberration after aberration；The face shape error data are the deviation of practical face shape relative theory face shape profile；
S5), stitching algorithm is interfered to carry out splicing by cylinder stitching algorithm and cylinder, obtains non-cylindrical to be measured
Unified face shape error.
As preferred technical solution, step S1) detailed process it is as follows：
First, the theoretical face shape profile of non-cylindrical to be measured is acquired by the design value that lens producer provides, specific to calculate
Formula is as follows：
Wherein z represents the rise of non-cylindrical to be measured；K represents quadratic surface constant；Y is represented perpendicular to non-cylindrical axis
The horizontal coordinate in direction, Y ∈ [- D/2, D/2], D represent the width of non-cylindrical lens clear aperature to be measured；R represents non-cylindrical
The vertex curvature radius in face；A4, A6..., A14Represent non-cylindrical coefficient；
Secondly, the radius R of best fit cylinder is calculated according to the theoretical face shape profile of non-cylindrical to be measuredbfc：
Wherein, the maximum value of rise z is represented；Then non-cylindrical degree is obtained by equation below：
The best fit cylinder is denoted as Cf, the non-cylindrical degree is inclined for non-cylindrical to be measured and best fit cylinder
Difference；
Then, the slope of non-cylindrical degree is calculated, determines the maximum of points and minimum point of slope, the maximum point is denoted as
A, the smallest point are denoted as B；It determines a bit, to be denoted as M, corresponding face shape is denoted as S between point M and point B in AB sectionsMBSo that
SMBTheoretical face shape profile and its best fit cylinder deviation in the range of dynamic measurement of Feisuo flat interferometer, at this time
Best fit cylinder is denoted as CMB；
Finally, according to the length of MB and best fit cylinder CMBRadius determine the F/ numbers of CGH cylindrical wave converters, according to
F/ numbers and overlap coefficient CoDivide sub-aperture；The overlap coefficient is between adjacent sub-aperture shared by overlapping region and single sub-aperture
The ratio in region sets Co=0.3.
As preferred technical solution, step S2) be specially：Least square is used according to the theoretical face shape profile of sub-aperture
Method calculates best fit cylinder, obtains the axial location parameter of best fit cylinder, and the axial location parameter is also known as sub-aperture
The nominal amount of exercise of diameter.
As preferred technical solution, step S3) it specifically includes：It is adjusted according to the nominal amount of exercise of sub-aperture to be measured not rounded
Cylinder makes a sub-aperture of non-cylindrical to be measured enter in the measurement visual angle of Feisuo flat interferometer；Then by adjusting CGH
Cylindrical wave converter rotates about central axis and changes rotation angle, generates the variable coma of size, tested to compensate
The aberration of sub-aperture reduces the residual aberration returned inside interferometer, obtains analysable interference pattern；Followed by Feisuo plane
Interferometer obtains measurement result, and the measurement result is a relative value, represents that practical face shape is generated with CGH cylindrical waves converter
Reference wavefront deviation.
As preferred technical solution, step S4) it specifically includes：To obtain the face shape error data of sub-aperture, first root
According to the amount of spin of CGH cylindrical wave converters, the nominal value for determining residual aberration is resolved by digitized measurement, is then tied from measurement
The nominal value of residual aberration is subtracted in fruit, obtains the face shape error data of sub-aperture；Finally according to the nominal value of residual aberration and
Measurement result obtains the face shape error data of other sub-apertures successively.
As preferred technical solution, step S5) it specifically includes：
First, according to the nominal amount of exercise of sub-aperture by the face shape error data of all sub-aperturesIt transforms to complete
Office's three-dimensional system of coordinate (x, y, z)；
Wherein, RbfcRepresent the radius of the best fit cylinder of sub-aperture, RbfRepresent the back focal length of CGH cylindrical wave converters,Represent the face shape error of sub-aperture；X represents the coordinate along non-cylindrical axis direction, and Y is represented perpendicular to non-cylindrical axis
The horizontal coordinate in direction；
Then slightly match the 3 d shape error information of sub-aperture using cylinder stitching algorithm, i.e., using overlay region in radius side
To deviation determine mutual alignment relation between adjacent sub-aperture, adjacent sub-aperture is adjusted using rigid transformation method according to this result
The space coordinate of diameter；Result after rough registration is then subtracted to the theoretical face shape profile of non-cylindrical to be measured, obtains sub-aperture
Face shape error；
Finally accurately splice the face shape error of all sub-apertures using cylinder interference stitching algorithm, obtain the complete of non-cylindrical
Bore face shape error.
The present invention is had the following advantages relative to the prior art and effect：
(1) system for measuring non-cylindrical optical component surface shape error of the invention is not required to additionally increase compensator,
CGH cylindrical wave converters need to be rotated, it will be able to generate the variable non-cylindrical wavefront of size, be measured for compensating off-axis sub-aperture
As a result the residual aberration in, so as to reduce measurement cost.
(2) system for measuring non-cylindrical optical component surface shape error of the invention only needs one-dimensional rotation CGH, easily behaviour
Make, and the mechanical precision of adjustment mechanism is easier to ensure that.
(3) measuring method provided by the present invention can significantly reduce the aberration of off-axis sub-aperture, obtain analysable dry
When relating to figure, and using existing method measurement non-cylindrical, since off-axis sub-aperture and best fit cylindrical surface deviation is too big,
Lead to not obtain analysable interference pattern.
Description of the drawings
Fig. 1 is the schematic diagram of measuring system of the present invention；Wherein, drawing reference numeral：1st, Feisuo flat interferometer；2nd, CGH cylinders
Wave converter；3rd, non-cylindrical to be measured；4th, non-cylindrical adjusting apparatus；5th, precise rotating platform.
Fig. 2 is the implementation steps schematic diagram of measuring method of the present invention.
Fig. 3 (a1)-Fig. 3 (b3) is in the present embodiment, does not rotate CGH cylindrical wave converters, simulates in off-axis sub-aperture
Locate the interference pattern and phase diagram that obtain；Wherein, Fig. 3 (a1), Fig. 3 (a2) and Fig. 3 (a3) are respectively the off-axis sub-aperture path position at 3
The interference pattern of acquisition；Fig. 3 (b1), Fig. 3 (b2) and Fig. 3 (b3) are respectively the corresponding phase of off-axis sub-aperture position acquisition at 3
Figure.
Fig. 4 (a1)-Fig. 4 (b3) is in the present embodiment, rotates CGH cylindrical wave converters, simulates and obtained at off-axis sub-aperture
The interference pattern and phase diagram taken；Wherein, Fig. 4 (a1), Fig. 4 (a2) and Fig. 4 (a3) are respectively the off-axis sub-aperture at as before 3
The interference pattern that path position obtains；Fig. 4 (b1), Fig. 4 (b2) and Fig. 4 (b3) are respectively the off-axis sub-aperture position at as before 3
It puts and obtains corresponding phase diagram.
Fig. 5 is in the present embodiment, and experiment measures the sub-aperture interference pattern of non-cylindrical to be measured.
Fig. 6 is in the present embodiment, and experiment measures the sub-aperture face shape error distribution map of non-cylindrical to be measured.
Fig. 7 is the unified face shape error distribution map of non-cylindrical to be measured in the present embodiment.
Specific embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, with reference to the accompanying drawings and embodiments, it is right
The present invention is further elaborated.It should be appreciated that specific embodiment described herein is only to explain the present invention, not
For limiting the present invention.
Embodiment 1
As shown in Figure 1, a kind of non-cylindrical based on rotation CGH interferes splicing measuring systems, including Feisuo plane interference
Instrument 1, CGH cylindrical waves converter 2, non-cylindrical to be measured 3, non-cylindrical adjusting apparatus 4 and precise rotating platform 5；The Feisuo plane
Interferometer 1 is used to generate plane wave；Before CGH cylindrical waves converter 2 by plane wave for being diffracted into cylindrical wave；CGH cylindrical waves turn
Parallel operation 2 is mounted on precise rotating platform 5, and between Feisuo flat interferometer 1 and non-cylindrical to be measured 3, the precise rotating platform 5
Control CGH cylindrical waves converter 2 rotates, and CGH cylindrical waves converter 2 is made to be rotated around the central axis of itself；It is described to be measured non-
Cylindrical surface 3 is mounted in non-cylindrical adjusting apparatus 4, adjustment machine of the non-cylindrical adjusting apparatus 4 for a five degree of freedom
Structure, for adjusting the spatial position of non-cylindrical 3 to be measured, including three rotations and two linear motions；The Feisuo plane is done
The optical axis of interferometer 1 and the optical axis coincidence of CGH cylindrical waves converter 2；Adjustment non-cylindrical adjusting apparatus 4 makes non-cylindrical 3 to be measured
Best fit cylinder axis overlapped with the focal axis line before the cylindrical wave of 2 diffraction of CGH cylindrical waves converter；The best-fit-circle
Mast axis refers to and the immediate axis with reference to non-cylindrical of non-cylindrical to be measured.
In the present embodiment 1, the plane wave that the Feisuo flat interferometer 1 is sent out forms column through CGH cylindrical waves converter 2
Non- cylindrical 3 to be measured is incident on before surface wave, again by CGH cylindrical waves converter 2 after non-cylindrical 3 to be measured reflection, most
1 inside of Feisuo flat interferometer is returned to afterwards with forming interference pattern with reference to the interference of light；Wherein, by changing CGH cylindrical waves converter 2
Rotation angle, generate the variable non-cylindrical wavefront of size and shape.
The principle of the measuring system of the present embodiment 1：Nominal amount of exercise is surveyed according to sub-aperture first and adjusts non-cylindrical to be measured,
The sub-aperture of non-cylindrical to be measured is made to enter in the measurement visual angle of interference system；Secondly rotation CGH cylindrical wave converters, make by
The residual aberration that Feisuo flat interferometer is returned after CGH cylindrical wave converters is minimum；Then according to the rotation of CGH non-cylindrical to be measured
Turn amount, determine that CGH rotates the aberration of post-compensation by digitized measurement；Then remaining off-axis sub-aperture is completed according to the method described above
The measurement of face shape error；The sub-aperture face shape error is finally converted into global three-dimensional coordinate data, is spliced using cylinder
Algorithm rough registration, then using cylinder interference stitching algorithm essence registration, you can the unified face shape for obtaining non-cylindrical to be measured is missed
Difference cloth.The measuring system of the present embodiment 1 only need to rotate CGH cylindrical wave converters without the additional increase compensator of requirement, you can
Reduce the residual aberration for returning to interferometer, measurement cost can be reduced；One-dimensional rotation CGH cylindrical wave converters are only needed, it is easy to operate,
Easily ensure the mechanical precision of adjustment platform.
Embodiment 2
It below will be to a kind of measurement of the non-cylindrical interference splicing measuring systems based on rotation CGH provided by the present invention
Method is described in detail.
As shown in Fig. 2, a kind of measuring method of the non-cylindrical interference splicing measuring systems based on rotation CGH, including under
State step：
S1 the F/ numbers of CGH cylindrical wave converters), are determined according to the theoretical face shape profile of non-cylindrical to be measured, divide sub-aperture
Diameter；Detailed process is as follows：
First, the theoretical face shape profile of non-cylindrical to be measured is acquired by the design value that lens producer provides, specific to calculate
Formula is as follows：
Wherein z represents the rise of non-cylindrical to be measured；K represents quadratic surface constant；Y is represented perpendicular to non-cylindrical axis
The horizontal coordinate in direction, Y ∈ [- D/2, D/2], D represent the width of non-cylindrical lens clear aperature to be measured；R represents non-cylindrical
The vertex curvature radius in face；A4, A6..., A14Represent non-cylindrical coefficient；
Secondly, the radius R of best fit cylinder is calculated according to the theoretical face shape profile of non-cylindrical to be measuredbfc：
Wherein, the maximum value of rise z is represented；Then non-cylindrical degree is obtained by equation below：
The best fit cylinder is denoted as Cf, the non-cylindrical degree is inclined for non-cylindrical to be measured and best fit cylinder
Difference；
Then, the slope of non-cylindrical degree is calculated, determines the maximum of points and minimum point of slope, the maximum point is denoted as
A, the smallest point are denoted as B；It determines a bit, to be denoted as M, corresponding face shape is denoted as S between point M and point B in AB sectionsMBSo that
SMBTheoretical face shape profile and its best fit cylinder deviation in the range of dynamic measurement of Feisuo flat interferometer, at this time
Best fit cylinder is denoted as CMB；
Finally, according to the length of MB and best fit cylinder CMBRadius determine the F/ numbers of CGH cylindrical wave converters, according to
F/ numbers and overlap coefficient CoSub-aperture is divided, the F is the back focal length of CGH and the ratio of diaphragm diameter；The overlap coefficient is
The ratio of overlapping region and region shared by single sub-aperture between adjacent sub-aperture, sets Co=0.3.
S2 the nominal amount of exercise of sub-aperture), is calculated according to the theoretical face shape profile of sub-aperture；
Best fit cylinder is calculated using least square method according to the theoretical face shape profile of sub-aperture, obtains best-fit-circle
The axial location parameter of column, the axial location parameter are also known as the nominal amount of exercise of sub-aperture.
S3 non-cylindrical to be measured and the posture of CGH cylindrical wave converters), are adjusted according to the nominal amount of exercise of sub-aperture, obtained
Obtain analysable interference pattern；
Non- cylindrical to be measured is adjusted according to the nominal amount of exercise of sub-aperture, enters a sub-aperture of non-cylindrical to be measured
In the measurement visual angle of Feisuo flat interferometer；Then it is rotated simultaneously about central axis by adjusting CGH cylindrical waves converter
Change rotation angle, generate the variable coma of size, to compensate the aberration of tested sub-aperture, reduce and return to Feisuo flat interferometer
Internal residual aberration, obtains analysable interference pattern；Measurement result is obtained followed by Feisuo flat interferometer.
S4), according to the amount of spin of CGH cylindrical wave converters, the nominal value of residual aberration is determined, so as to obtain sub-aperture
Face shape error data；
The nominal value of the residual aberration refers to that theoretical face shape profile subtracts the picture that rotation CGH cylindrical waves converter generates
Remaining aberration after difference；The face shape error data refer to the deviation of practical face shape relative theory face shape profile；To obtain son
The face shape error data in aperture first according to the amount of spin of CGH cylindrical wave converters, are resolved by digitized measurement and determine residue
Then the nominal value of aberration subtracts the nominal value of residual aberration from measurement result, obtain the face shape error data of sub-aperture；Most
Obtain the face shape error data of other sub-apertures successively according to the method described above afterwards.
S5), stitching algorithm is interfered to carry out splicing by cylinder stitching algorithm and cylinder, obtains non-cylindrical to be measured
Unified face shape error；Detailed process is as follows：
First, according to the nominal amount of exercise of sub-aperture by the face shape error data of all sub-aperturesIt transforms to complete
Office's three-dimensional system of coordinate (x, y, z)；
Wherein, RbfcRepresent the radius of the best fit cylinder of sub-aperture, RbfRepresent the back focal length of CGH,Represent sub-aperture
Face shape error；X represents the coordinate along non-cylindrical axis direction, and Y represents the level perpendicular to non-cylindrical axis direction
Coordinate.
Then slightly match the 3 d shape error information of sub-aperture using cylinder stitching algorithm, i.e., using overlay region in radius side
To deviation determine mutual alignment relation between adjacent sub-aperture, adjacent sub-aperture is adjusted using rigid transformation method according to this result
The space coordinate of diameter；Result after rough registration is then subtracted to the theoretical face shape profile of non-cylindrical to be measured, obtains sub-aperture
Face shape error；
Finally accurately splice the face shape error of all sub-apertures using cylinder interference stitching algorithm, obtain the complete of non-cylindrical
Bore face shape error.
It is a concrete application example below
Measurand be a plano-convex non-cylindrical lens, vertex curvature radius 13.984mm, clear aperature 20mm*
20mm, quadratic surface constant k=1, non-cylindrical coefficient are as shown in table 1.According to above-mentioned non-cylindrical parameter, using the present embodiment
The 2 method calculating provided acquire the best-fit-circle column parameter of off-axis sub-aperture, as shown in table 2.In order to be spelled with existing interference
The method of connecing compares, and without rotation CGH cylindrical wave converters in sub-aperture measurement process, the parameter adjustment provided according only to table 1 is treated
Non- cylindrical is surveyed, the face shape error data of each sub-aperture are then obtained using interferometer measuration system.Such as Fig. 3 (a1)-Fig. 3 (b3)
For no rotation CGH cylindrical wave converters, the interference pattern and phase diagram obtained at off-axis sub-aperture is simulated.Fig. 3 (a1), Fig. 3
(a2) and Fig. 3 (a3) be respectively at 3 off-axis sub-aperture position acquisition interference pattern；Fig. 3 (b1), Fig. 3 (b2) and Fig. 3 (b3) points
Not Wei at 3 the corresponding phase diagram of off-axis sub-aperture position acquisition；Fig. 4 (a1)-Fig. 4 (b3) is in the present embodiment 2, rotates CGH
Cylindrical wave converter simulates the interference pattern and phase diagram obtained at off-axis sub-aperture；Fig. 4 (a1), Fig. 4 (a2) and Fig. 4 (a3)
The interference pattern of off-axis sub-aperture position acquisition respectively at as before 3；Fig. 4 (b1), Fig. 4 (b2) and Fig. 4 (b3) are respectively
For the corresponding phase diagram of sub-aperture position acquisition off-axis at as before 3.Compare Fig. 3 (a1)-Fig. 3 (b3) and Fig. 4 (a1)-
The result of Fig. 4 (b3) is obtained it is found that the measuring method that the present embodiment 2 is provided can significantly reduce the aberration of off-axis sub-aperture
Analysable interference pattern, and use existing method measure non-cylindrical when, due to off-axis sub-aperture theoretical face shape profile with most
The deviation on good fitting cylindrical surface is too big, leads to not obtain analysable interference pattern.
1 non-cylindrical coefficient of table
According to the parameter in table 2, experiment measurement is carried out to above-mentioned non-cylindrical lens using stitching interferometer method, such as Fig. 5 institutes
It is shown as the sub-aperture interference pattern that experiment measures non-cylindrical to be measured；Fig. 6 is the sub-aperture diametric plane shape that experiment measures non-cylindrical to be measured
Error map.Fig. 7 is the unified face shape error distribution map of non-cylindrical to be measured.
The best-fit-circle column parameter of 2 off-axis sub-aperture of table
It is worth noting that, in embodiment 1 and embodiment 2, included each unit only according to function logic into
What row divided, but above-mentioned division is not limited to, as long as corresponding function can be realized；In addition, each functional unit
Specific name is also only to facilitate mutually distinguish, the protection domain being not intended to restrict the invention.
In addition, one of ordinary skill in the art will appreciate that all or part of step in realization the various embodiments described above is can
It is completed with instructing relevant hardware by program, corresponding program can be stored in computer read/write memory medium,
The storage medium, such as ROM/RAM, disk or CD.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all essences in the present invention
All any modification, equivalent and improvement made within refreshing and principle etc., should all be included in the protection scope of the present invention.
Claims (8)
1. a kind of non-cylindrical based on rotation CGH interferes splicing measuring systems, which is characterized in that including Feisuo flat interferometer
(1), CGH cylindrical waves converter (2), non-cylindrical to be measured (3), non-cylindrical adjusting apparatus (4) and precise rotating platform (5)；It is described
Feisuo flat interferometer (1) is for generating plane wave；The CGH cylindrical waves converter (2) by plane wave for being diffracted into cylinder
Wavefront, CGH cylindrical waves converter (2) is on precise rotating platform (5), and positioned at Feisuo flat interferometer (1) and to be measured not rounded
Between cylinder (3)；The precise rotating platform (5) makes CGH cylindrical wave converters for CGH cylindrical waves converter (2) to be controlled to rotate
(2) it is rotated around the central axis of itself；The non-cylindrical to be measured (3) is described in non-cylindrical adjusting apparatus (4)
Adjustment mechanism of the non-cylindrical adjusting apparatus (4) for a five degree of freedom, for adjusting the space bit of non-cylindrical to be measured (3)
It puts, including three rotations and two linear motions；The optical axis of the Feisuo flat interferometer (1) and CGH cylindrical waves converter (2)
Optical axis coincidence；Adjustment non-cylindrical adjusting apparatus (4) makes the best fit cylinder axis of non-cylindrical to be measured (3) and CGH columns
Focal axis line before the cylindrical wave of surface wave converter (2) diffraction overlaps.
2. the non-cylindrical according to claim 1 based on rotation CGH interferes splicing measuring systems, which is characterized in that institute
It is to be measured not rounded through being incident on before CGH cylindrical waves converter (2) formation cylindrical wave to state the plane wave that Feisuo flat interferometer (1) is sent out
Cylinder (3) again by CGH cylindrical waves converter (2) after non-cylindrical to be measured (3) reflection, finally returns to Feisuo plane
Interferometer (1) is internal with forming interference pattern with reference to the interference of light；Wherein, by changing the rotation angle of CGH cylindrical waves converter (2)
Degree generates the variable non-cylindrical wavefront of size and shape.
3. the survey of the non-cylindrical interference splicing measuring systems based on rotation CGH according to any one of claim 1-2
Amount method, which is characterized in that include the following steps：
S1 the F/ numbers of CGH cylindrical wave converters), are determined according to the theoretical face shape profile of non-cylindrical to be measured, divide sub-aperture；Institute
F is stated as the back focal length of CGH cylindrical wave converters and the ratio of diaphragm diameter；
S2 the nominal amount of exercise of sub-aperture), is calculated according to the theoretical face shape profile of sub-aperture；
S3 non-cylindrical to be measured and the posture of CGH cylindrical wave converters), are adjusted according to the nominal amount of exercise of sub-aperture, acquisition can
The interference pattern of parsing；
S4), according to the amount of spin of CGH cylindrical wave converters, the nominal value of residual aberration is determined, so as to obtain the face shape of sub-aperture
Error information；The nominal value of the residual aberration is that theoretical face shape profile subtracts the aberration that rotation CGH cylindrical waves converter generates
Remaining aberration afterwards；The face shape error data are the deviation of practical face shape relative theory face shape profile；
S5), stitching algorithm is interfered to carry out splicing by cylinder stitching algorithm and cylinder, obtains the full mouth of non-cylindrical to be measured
Diameter face shape error.
4. the measuring method of the non-cylindrical interference splicing measuring systems according to claim 3 based on rotation CGH, special
Sign is, step S1) detailed process is as follows：
First, the theoretical face shape profile of non-cylindrical to be measured is acquired by the design value that lens producer provides, specific formula for calculation
It is as follows：
Wherein z represents the rise of non-cylindrical to be measured；K represents quadratic surface constant；Y is represented perpendicular to non-cylindrical axis direction
Horizontal coordinate, Y ∈ [- D/2, D/2], D represent the width of non-cylindrical lens clear aperature to be measured；R represents non-cylindrical
Vertex curvature radius；A4, A6..., A14Represent non-cylindrical coefficient；
Secondly, the radius R of best fit cylinder is calculated according to the theoretical face shape profile of non-cylindrical to be measuredbfc：
Wherein, h represents the maximum value of rise z；Then non-cylindrical degree is obtained by equation below：
The best fit cylinder is denoted as Cf, the non-cylindrical degree is non-cylindrical to be measured and the deviation of best fit cylinder；
Then, the slope of non-cylindrical degree is calculated, determines the maximum of points and minimum point of slope, the maximum point is denoted as A, institute
It states smallest point and is denoted as B；It determines a bit, to be denoted as M, corresponding face shape is denoted as S between point M and point B in AB sectionsMBSo that SMB's
The deviation of theoretical face shape profile and its best fit cylinder is in the range of dynamic measurement of Feisuo flat interferometer, at this time best
Fitting cylinder is denoted as CMB；
Finally, according to the length of MB and best fit cylinder CMBRadius determine the F/ numbers of CGH cylindrical wave converters, according to F/ numbers
With overlap coefficient CoDivide sub-aperture；The overlap coefficient overlapping region and region shared by single sub-aperture between adjacent sub-aperture
Ratio, set Co=0.3.
5. the measuring method of the non-cylindrical interference splicing measuring systems according to claim 3 based on rotation CGH, special
Sign is, step S2) be specially：
Best fit cylinder is calculated using least square method according to the theoretical face shape profile of sub-aperture, obtains best fit cylinder
Axial location parameter, the axial location parameter are also known as the nominal amount of exercise of sub-aperture.
6. the measuring method of the non-cylindrical interference splicing measuring systems according to claim 3 based on rotation CGH, special
Sign is, step S3) it specifically includes：
Non- cylindrical to be measured is adjusted according to the nominal amount of exercise of sub-aperture, a sub-aperture of non-cylindrical to be measured is made to enter Feisuo
In the measurement visual angle of flat interferometer；Then it rotates and changes about central axis by adjusting CGH cylindrical wave converters
Rotation angle generates the variable coma of size, to compensate the aberration of tested sub-aperture, reduces the remaining picture returned inside interferometer
Difference obtains analysable interference pattern；Measurement result is obtained followed by Feisuo flat interferometer, the measurement result is a phase
To value, practical face shape and the deviation of reference wavefront that CGH cylindrical waves converter generates are represented.
7. the measuring method of the non-cylindrical interference splicing measuring systems according to claim 3 based on rotation CGH, special
Sign is, step S4) it specifically includes：To obtain the face shape error data of sub-aperture, turned first according to CGH cylindrical wave converters
Momentum resolves the nominal value for determining residual aberration by digitized measurement, and the name of residual aberration is then subtracted from measurement result
Justice value, obtains the face shape error data of sub-aperture；Other are finally obtained according to the nominal value of residual aberration and measurement result successively
The face shape error data of sub-aperture.
8. the measuring method of the non-cylindrical interference splicing measuring systems according to claim 3 based on rotation CGH, special
Sign is, step S5) it specifically includes：
First, according to the nominal amount of exercise of sub-aperture by the face shape error data of all sub-aperturesTransform to the overall situation three
Dimension coordinate system (x, y, z)；
Wherein, RbfcRepresent the radius of the best fit cylinder of sub-aperture, RbfRepresent the back focal length of CGH cylindrical wave converters,Table
Show the face shape error of sub-aperture；X represents the coordinate along non-cylindrical axis direction, and Y is represented perpendicular to non-cylindrical axis side
To horizontal coordinate；
Then slightly match the 3 d shape error information of sub-aperture using cylinder stitching algorithm, i.e., using overlay region in radial direction
Deviation determines the mutual alignment relation between adjacent sub-aperture, according to this result using rigid transformation method adjustment adjacent sub-aperture
Space coordinate；Result after rough registration is then subtracted to the theoretical face shape profile of non-cylindrical to be measured, obtains the face shape of sub-aperture
Error；
Finally accurately splice the face shape error of all sub-apertures using cylinder interference stitching algorithm, obtain the unified of non-cylindrical
Face shape error.
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