CN108362225B - Measuring device and measuring method for conical mirror cylindrical surface shape - Google Patents

Abstract

A measuring device and a measuring method for the surface shape of a cylindrical mirror of a conical mirror are provided, the measuring device comprises a wave surface measuring interferometer, an interferometer bracket, a precise rotating platform and a rotating platform real-time measuring system, and the wave surface measuring interferometer is arranged on the interferometer bracket; the real-time measuring system of the rotary table comprises an auxiliary measuring cylinder and 5 precise displacement measuring sensors. The invention has the characteristics of high precision, low cost, high universality, capability of simultaneously measuring the surface shape information of the element to be measured and the rotation error of the main shaft of the precision rotating platform and simultaneously removing synchronous errors and asynchronous errors.

Description

Measuring device and method for cylindrical mirror surface shape of conical mirror

technical field

The invention relates to the field of interferometric measurement, in particular to a measuring device and method for the surface shape of a conical mirror and a cylindrical mirror.

Background technique

The conic mirror is a special rotationally symmetric aspherical surface, a point light source on its axis will form a series of image points along its axis, and it can also transform the collimated beam into a ring beam. These characteristics have been applied to high-resolution Optical coherence tomography, cold atom capture, lithography machine ring illumination generation, etc. A cylindrical mirror is also a rotationally symmetric aspheric surface capable of focusing a collimated beam of light into a line. However, the deterministic optical processing of conical mirrors and cylindrical mirrors has always been limited by their surface shape detection technology, which affects their application range and cost. The difference between the conical mirror and the cylindrical mirror is that the generatrix of the conical mirror has a certain angle with its axis of rotational symmetry, while the generatrix of the cylindrical mirror is parallel to its axis of rotational symmetry, that is, the angle is zero.

Prior technology [1] (Jun Ma, Christof Pruss, Rihong Zhu, Zhishan Gao, Caojin Yuan, and Wolfgang Osten,"An absolute test for axicon surfaces,"Opt.Lett.36, 2005-2007(2011)) and in Advanced Technology 2 (Jun Ma, Christof Pruss, Matthias Rihong Zhu, Zhishan Gao, Caojin Yuan, Wolfgang Osten, "Axicon metrology using high linedensity computer-generated holograms," Proc. SPIE 8082, Optical Measurement Systems for Industrial Inspection VII, 80821I (2011)) all use computational holograms as compensation mirrors, Detect the surface shape of the conical mirror; this method has high measurement accuracy, but it needs to make a compensating mirror element for each conical mirror to be tested, which increases the measurement cost and measurement cycle, and has poor versatility. In addition, when measuring a large-diameter conical mirror, a larger-diameter compensating mirror element and an interferometer are required, which also increases the measurement cost and the difficulty of making the compensating mirror.

Prior art [2] (Yuan Qiao, Zeng Aijun, Zhang Shanhua, Huang Huijie, Axicon Mirror Surface Shape and Cone Angle Detection Method, Chinese Invention Patent 201310180723.X) discloses a conical mirror surface shape measurement method. This method is actually a measurement of the transmitted wavefront of the conical mirror. The test light path passes through different test areas of the conical mirror during the test. Although the measurement results can evaluate the surface quality of the tested conical mirror, the measurement results cannot be used for As the basis for feedback processing; and this method cannot be used to measure the surface shape of concave mirrors.

The prior art [3] (Xu Jiajun, Jia Xin, Xu Fuchao, Xing Tingwen, an online detection and processing device and method for a convex conical mirror, Chinese invention patent 201510351236.4) uses a laser displacement sensor to detect the shape of a conical mirror through point scanning. The precision of the displacement sensor and the rotation system puts forward very high requirements, which increases the system cost; and this method cannot be used to measure the shape of the concave cone mirror.

The prior technology [4] (axicon cylindrical mirror surface shape measurement device and measurement method, Chinese invention patent) uses a wave surface measurement interferometer to output a collimated beam to vertically irradiate a busbar of the optical element under test, thereby measuring the surface of the busbar shape information. This method relies on the accuracy of the precision turntable, and needs to calibrate the spindle rotation error of the precision turntable in advance and can only remove the synchronization error.

The surface shape test method of cylindrical mirror is similar to that of cone mirror. American Diffraction International Company, Arizona Optical Metrology LLC, etc. all use computational hologram compensation mirrors for measurement. Different F numbers and apertures require different compensation mirrors.

At present, there is no general-purpose, high-precision, and low-cost measuring device and method for the axicon surface shape.

Contents of the invention

The object of the present invention is to overcome above-mentioned deficiencies in the prior art, provide a kind of conical mirror and cylindrical mirror surface shape measuring device and measuring method, measuring device has versatility, can measure different calibers, different vertex angles of convex conical mirror and concave The surface shape of the cone mirror can also measure cylindrical mirrors with different diameters and different rotation angle ranges. The measurement system is simple and the cost is low. When measuring the surface shape information of the component to be measured, it can also measure the rotation error of the spindle of the precision rotary table, and at the same time remove the synchronization error and Asynchronous error, higher measurement accuracy.

Technical solution of the present invention is as follows:

A measuring device for a conical mirror and a cylindrical mirror surface, characterized in that it includes a wave surface measurement interferometer, an interferometer bracket, a precision rotary table and a turntable real-time measurement system; the wave surface measurement interferometer is installed on the interferometer bracket; The real-time measurement system of the turntable includes an auxiliary measurement cylinder and 5 precision displacement measurement sensors,

The auxiliary measuring cylinder is installed on the precision turntable, the central axis of the auxiliary measuring cylinder is coaxial with the rotation axis of the precision turntable; the five precision displacement measuring sensors, They are the precision displacement measurement sensor for the Z channel displacement in the z-axis direction, the x-axis direction and the y-axis direction outside the auxiliary measuring cylinder, the precision displacement measurement sensor for the displacement of the X channel in the upper section and the X channel in the lower section. The precise displacement measuring sensor of displacement, the precise displacement measuring sensor of the upper section Y channel displacement and the precise displacement measuring sensor of the lower section Y channel displacement, the upper section and the lower section are two horizontal planes with a certain distance, and the vertical distance is recorded as l; The upper surface of the auxiliary measuring cylinder is used for placing the conical mirror or cylindrical mirror of the optical element to be measured.

The aconic mirror is a convex aconic mirror, or a concave aconic mirror with an apex angle greater than or equal to 90 degrees;

The wave surface measuring interferometer is a Fizeau interferometer with a flat standard mirror, or a Tiemann-Green interferometer, or a Mach-Zehnder interferometer, or a point diffraction interferometer outputting a plane light wave, or a single interferogram measuring interferometer , or a dynamic measurement interferometer, or a high-speed dynamic measurement interferometer.

The interferometer bracket is a multi-dimensional adjustment bracket.

Utilize the measuring method of above-mentioned conical mirror and cylindrical mirror surface shape measuring device, this method comprises the following steps:

①Establish the coordinate system of the detection system, take the rotation axis direction of the precision rotary table as the Z direction, and the two orthogonal directions in the radial direction of the precision rotary table are the X direction and the Y direction respectively, and the busbar of the optical element under test and the rotation of the optical element under test The angle between the symmetry axes is denoted as α, and the projection of the generatrix perpendicular to the outgoing light of the wave surface measuring interferometer on the XY plane coincides with the X axis; the range of the rotation angle of the precision rotary table is the same as the range of the rotation angle of the measured optical element ; Divide the range of rotation angles of the precision turntable into N equal parts, and record it as θ _i , where i=1, 2, 3, ..., N, N is a positive integer, θ ₁ is the starting angle, which is consistent with the measured optical element Corresponding to the starting position of the measured surface;

② Calibrate the roundness error h(θ _i ) and flatness deviation z ₀ (θ _i ) of the auxiliary measuring surface of the auxiliary measuring cylinder;

③Adjust the measuring device so that the wave surface measurement interferometer observes a linear interferogram corresponding to a busbar of the optical component under test, the number of interference fringes is the least and the interference fringes are the widest, and the center position of the interference fringe area is measured on the busbar of the optical component under test. At this time, the center position of the interference fringe area is perpendicular to the outgoing light of the wave surface measurement interferometer;

④ Rotate the rotation angle θ of the precision rotary table to θ ₁ , which is the initial angular position;

⑤Use the wave surface measurement interferometer to measure, save the surface shape measurement result S(θ _i ,w) of the centerline pixel of the effective area of the interferogram; the real-time measurement system of the turntable measures the axial runout of each rotation position of the precision turntable Error δz(θ _i ), radial runout error δx(θ _i ), rotation inclination error in X direction T _x (θ _i ); w is the bus coordinates, w=0,1,2,…, W-1, W is A positive integer, representing the pixel coordinates along the length direction of the busbar of the measured optical element;

⑥ Rotate the precision rotary table to the next rotation angle position of θ _i rotation angle, repeat step ⑤, until the measurement of all N rotation angle positions is completed; respectively take S(θ ₁ ,w) with different w as the starting point , w=0,1,2,...,W-1, carry out the phase unwrapping of the corresponding phase for the W group of surface shape measurement data S(θ _i ,w)(i=1,2,3,...,N) , so that the W group surface shape measurement data S(θ _i ,w) are all continuous data;

⑦ According to the following formula (1), remove from S(θ _i ,w) the calibrated precision rotary table’s rotational axial runout error δz(θ _i ), rotational radial runout error δx(θ _i ), and rotational tilt error T _x (θ _i ) influence on the measurement results,

F`(θ _i ,w)=S(θ _i ,w)-δz(θ _i )·sin(α)-δx(θ _i )·cos(α)-Tx(θ _i )·w·PW, ( 1)

Where PW is the width of each coordinate pixel corresponding to the bus coordinates;

⑧From F`(θ <sub>i</sub> ,w), randomly select K groups with different generatrix coordinates w to remove the surface shape measurement data F`(θ _i ,w _k ), where i=1,2,3,..., N, k=1, 2, 3,..., K, according to the rotation clamping eccentricity error separation method, separate the F`(θ _i ,w _k ) detection error E(θ _i ,w _k ); the average value E(θ _i ) of K group E(θ _i ,w _k ) is:

E(θ _i )＝(E(θ _i ,w ₁ )+E(θ _i ,w ₂ )+…+E(θ _i ,w _K ))/K,

Remove the detection error E(θ _i ) caused by the installation eccentricity of the optical component under test from F`(θ _i ,w), and obtain the surface shape detection result F(θ _i ,w) of the optical component under test,

F(θ _i ,w)=F`(θ _i ,w)-E(θ _i ).

The method for calibrating the roundness deviation h(θ _i ) of the auxiliary measuring surface of the auxiliary measuring cylinder adopts a multi-step method, a multi-point method, or a reverse method.

The method for calibrating the flatness deviation z ₀ (θ _i ) of the auxiliary measurement surface of the auxiliary measurement cylinder adopts the laser plane method, the level method, or the three-coordinate measurement method.

The method for calibrating the rotation tilt error T _x (θ _i ) of the precision rotary table, T _y (θ _i ) adopts the separation method of the spindle rotation error of multi-channel data acquisition; the tilt error T _x (θ _i ), T _y ( θ _i ) is calculated by the following formula:

y ₁ (θ _i ) is the result of subtracting the roundness error h ₁ (θ _i ) of the auxiliary measuring surface of the auxiliary measuring cylinder in the upper section from the displacement measured by the precision displacement measuring sensor of the Y channel in the upper section; y ₂ (θ _i ) is the result of subtracting the roundness error h ₂ (θ _i ) of the auxiliary measuring surface of the auxiliary measuring cylinder in the lower section from the displacement measured by the precise displacement measuring sensor of the Y channel in the lower section.

The method for calibrating the axial runout error δz(θ _i ) of the precision rotary table uses the displacement z(θ _i ) measured by the precise displacement measurement sensor of the Z channel minus the auxiliary measurement of the auxiliary measuring cylinder The flatness deviation z ₀ (θ _i ) of the surface; the method of the rotation radial runout error δx(θ _i ) adopts the spindle rotation error separation method of multi-channel data acquisition, and the least square circle centers of the upper channel and the lower channel are respectively O ₁ (a ₁ ,b ₁ ) and O ₂ (a ₂ ,b ₂ ), the rotational radial runout error δx(θ _i ) is calculated by the following formula:

δ _x (θ _i )＝-l·T _y (θ _i )+(a ₂ -a ₁ )·cos(θ)+(b ₂ -b ₁ )·sin(θ)

The method for separating the eccentric error of the rotating clamping is the best sinusoidal curve fitting method, or the frequency domain Fourier transform filtering method.

The principle of the present invention is to measure only the surface shape of one busbar on the surface of the measured optical element each time, and measure different busbars through the scanning of the precision rotary table; eliminate the axial and radial runout and inclination of the precision turntable from the measurement results of different busbars, And the error caused by rotation eccentricity, that is, the surface shape measurement result of the optical element under test is obtained.

The advantage of the present invention is that the measuring system has versatility, can measure the surface shapes of convex cone mirrors and concave cone mirrors with different calibers and different vertex angles, and can also measure cylindrical mirrors with different diameters and different rotation angle ranges. The measuring system is simple and the cost is relatively low. Low, while measuring the surface shape information of the component to be tested, it can also measure the rotation error of the spindle of the precision rotary table, and remove the synchronous error and asynchronous error at the same time, and the measurement accuracy is higher.

Description of drawings

Fig. 1 is the structural representation of the improved measuring device of tapered mirror cylinder mirror shape of the present invention;

Fig. 2 is a schematic diagram of the coordinate relationship and the positional relationship of the precision displacement measurement sensor in the measurement process of the present invention;

Fig. 3 is the structural representation of an embodiment of the improved measuring device of conical mirror cylinder mirror shape of the present invention;

Fig. 4 is the structural representation of an embodiment of the improved measuring device of conical mirror cylinder mirror shape of the present invention;

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, but the embodiments do not limit the protection scope of the present invention.

Fig. 1 is the structural representation of the improved measuring device of conical mirror cylindrical mirror shape of the present invention, as seen from the figure, the measuring device of conical mirror of the present invention and cylindrical mirror shape, comprises wave front measurement interferometer 1, interferometer support 2, Precision rotary table 12 and turntable real-time measurement system; described wave surface measurement interferometer 1 is installed on the interferometer bracket 2; described turntable real-time measurement system includes auxiliary measuring cylinder 3 and 5 precision displacement measurement sensors,

Described auxiliary measurement cylinder 3 is installed on the described precision turntable 12, and the central axis of described auxiliary measurement cylinder 3 is coaxial with the rotation axis of described precision turntable 12; The displacement measurement sensors are respectively the precision displacement measurement sensors 5 placed in the z-axis direction, the x-axis direction, and the y-axis direction outside the auxiliary measuring cylinder 3, and the precise displacement measurement sensors for the displacement of the X-channel on the upper section The precise displacement measuring sensor 8 of the sensor 6 and the displacement of the X channel of the lower section, the precise displacement measuring sensor 7 of the displacement of the Y channel of the upper section and the precise displacement measuring sensor 9 of the displacement of the Y channel of the lower section, the upper section 10 and the lower section 11 are There are two horizontal planes with a certain distance, and the vertical distance is recorded as 1; the upper surface of the auxiliary measuring cylinder 3 is used for placing the conical mirror or cylindrical mirror of the optical element 4 to be measured.

Fig. 1 is a schematic diagram of the structure of the device of the present invention for measuring a convex aconic mirror, including a wave surface measurement interferometer 1, an interferometer bracket 2, an auxiliary measuring cylinder 3, and a precision rotary table 12, and the real-time measurement system of the rotary table includes a Z-channel precision displacement measurement sensor 5 , the X channel precision displacement measurement sensor 6 of the upper section 10, the Y channel precision displacement measurement sensor 7 of the upper section 10, the X channel precision displacement measurement sensor 8 of the lower section 11 and the Y channel precision displacement measurement sensor 9 of the lower section 11 and auxiliary Measuring a cylinder 3; the wave surface measurement interferometer 1 is installed on the interferometer bracket 2; the wave surface measurement interferometer 1 outputs a collimated light beam and has a plane reference optical path; the measured optical element 4 is a convex Axicon; the outgoing light of the wavefront measuring interferometer 1 is incident on the surface of the measured optical element 4, and the outgoing light of the wavefront measuring interferometer 1 is perpendicular to a generatrix of the measured optical element 4, so that the light incident on the generatrix Return along the original path, received by the wave surface measuring interferometer 1 and generate an interference signal with the reference light; the measured optical element 4 is installed on the precision rotary table 12, and the rotational symmetry axis of the measured optical element 4 is aligned with the precision rotary table 12 The axis of rotation is aligned; the X channel precision displacement measurement sensor 6 of the upper section 10, the X channel precision displacement measurement sensor 8 of the lower section 11 and the Y channel precision displacement measurement sensor 7 of the upper section 10, and the Y channel of the lower section 11 The precision displacement measurement sensors 9 are respectively placed in the same vertical plane and the two planes are perpendicular to each other, the X channel precision displacement measurement sensor 6 of the upper section 10, the Y channel precision displacement measurement sensor 7 of the upper section 10 and the lower section 11 The X-channel precision displacement measurement sensor 8 and the Y-channel precision displacement measurement sensor 9 of the lower section 11 are respectively placed in the same horizontal plane, and the detection direction of the precision displacement measurement sensor 5 is perpendicular to the precision rotary table 12;

Described wave surface measurement interferometer 1 is the Fizeau interferometer with plane standard mirror, or Tieman Green interferometer, or Mach-Zehnder interferometer, or the point diffraction interferometer of output plane light wave;

The wave surface measurement interferometer 1 is a phase shift measurement interferometer, or a single interferogram measurement interferometer, or a dynamic measurement interferometer, or a high-speed dynamic measurement interferometer;

The measuring device for the conical mirror and cylindrical mirror surface shape, the real-time measurement system of the turntable includes an auxiliary measuring cylinder 3 and 5 precision displacement measurement sensors, and the auxiliary measuring cylinder 3 is installed on the precision rotating On the platform 12, its central axis is aligned with the rotation axis of the precision rotary table; the five precision displacement measurement sensors include a precision displacement measurement sensor for detecting the displacement of the Z channel, two precision displacement measurement sensors for detecting the displacement of the X channel, and two A precision displacement measurement sensor for detecting Y channel displacement, two X channel precision displacement measurement sensors and two Y channel precision displacement measurement sensors are respectively placed in the upper and lower sections; the distance between the upper section and the lower section is recorded as l;

The interferometer support 2 can adjust the installation direction of the wave surface measurement interferometer, thereby adjusting the outgoing direction of the collimated beam of the wave surface measurement interferometer;

The interferometer bracket 2 can drive the wavefront measurement interferometer 1 to perform a translational movement in a direction parallel to the rotation axis of the precision rotary table 12, thereby measuring different areas on the surface of the optical element under test;

Utilize the measuring method of the improved measuring device of above-mentioned tapered mirror cylinder mirror shape, it is characterized in that the method comprises the following steps:

1. Establish the coordinate system of the detection system. Fig. 2 is a schematic diagram of the coordinate relationship in the measurement process of the present invention. The detection direction of the precision displacement measurement sensor 5 is along the Z-axis direction, and the precision displacement measurement sensors 6 and 8 are placed along the X-axis direction, and along the Y-axis Place the precision displacement measuring sensors 7 and 9 in the same direction; the direction of the rotation axis of the precision turntable 12 is the Z direction, and the two radially orthogonal directions of the precision turntable 12 are respectively the X direction and the Y direction. The included angle between the axes of rotational symmetry of the measuring optical element 4 is denoted as α, and the projection of the generatrix perpendicular to the outgoing light of the wave surface measuring interferometer 1 on the XY plane coincides with the X axis; The rotation angle range of the element 4 is the same; the rotation angle range N of the precision rotary table 12 is equally divided, and is recorded as θ _i , where i=1, 2, 3, ..., N, N is a positive integer, and θ ₁ is the starting angle , corresponding to the initial position of the measured surface of the measured optical element 4;

② Calibrate the roundness deviation h(θ _i ) and flatness deviation z ₀ (θ _i ) of the auxiliary measuring surface of the auxiliary measuring cylinder 3;

③Adjust the measuring device, and the wave surface measurement interferometer observes the linear interferogram corresponding to a busbar of the measured optical component, so that the number of interference fringes is the least and the interference fringes are the widest. The central position of the time interference fringe area is perpendicular to the outgoing light of the wave surface measurement interferometer;

④ Rotate the rotation angle θ of the precision rotary table 12 to θ ₁ , which is the starting angle position;

⑤ Use the wave surface measurement interferometer 1 to measure, and save the surface shape measurement result S(θ _i , w) of the centerline pixel of the effective area of the interferogram; Runout error δz(θ _i ), radial runout error δx(θ _i ), rotation inclination error in X direction T _x (θ _i ); w is the bus coordinates, w=0,1,2,...,W-1,W is a positive integer, representing the pixel coordinates along the length direction of the busbar of the measured optical element 4;

⑥ Rotate the precision rotary table 12 to the next rotation angle position in the θ _i rotation angle, and repeat step ⑤ until the measurement of all N rotation angle positions is completed; S(θ ₁ ,w) with different w is used as the starting point respectively, w =0,1,2,...,W-1, carry out the phase unwrapping of the corresponding phase to the W group surface shape measurement data S(θ _i ,w)(i=1,2,3,...,N), so that W group surface shape measurement data S(θ _i ,w) are all continuous data;

⑦ According to formula (1), remove from S(θ _i , w) the calibrated precision rotary table 12’s rotational axial runout error δz(θ _i ), rotational radial runout error δx(θ _i ), rotational tilt error T _x (θ _i ) influence on measurement results F`(θ _i ,w)=S(θ _i ,w)-δz(θ _i )·sin(α)-δx(θ _i )·cos(α)-Tx( θ _i )·w·PW-h(θ _i ), (1)

Where PW is the width of each coordinate pixel corresponding to the bus coordinates;

⑧From F`(θ <sub>i</sub> ,w), randomly select K groups with different generatrix coordinates w to remove the surface shape measurement data F`(θ _i ,w _k ), where i=1,2,3,..., N, k=1, 2, 3, ..., K, according to the rotation clamping eccentricity error separation method, separate the F`(θ _i , w _k ) detection error E(θ _i ,w _k ); the average value E(θ _i ) of K groups E(θ _i ,w _k ) is

E(θ _i )＝(E(θ _i ,w ₁ )+E(θ _i ,w ₂ )+…+E(θ _i ,w _K ))/K,

Remove the detection error E(θ _i ) caused by the installation eccentricity of the measured optical component from F`(θ _i ,w), and obtain the surface shape detection result F(θ _i ,w) of the measured optical component 4,

F(θ _i ,w)=F`(θ _i ,w)-E(θ _i );

The method of calibration and auxiliary measurement of the roundness deviation h(θ _i ) of the auxiliary measurement surface of the cylinder 3 adopts a multi-step method (see prior art 5, Ye Jingsheng, Gu Qitai, Zhang Yanshen. On the measurement of multi-step error separation technology Accuracy [J]. Acta Metrology, 1990,11(2):119-123.), multi-point method (see prior art 6, Su Heng, Hong Maisheng, Wei Yuanlei, etc. On-line detection and signal of radial error motion of machine tool spindle Processing [J]. Chinese Journal of Mechanical Engineering, 2002,38(6):56-60.), or reverse method (see prior art 7, Donaldson R RA Simple Method for Separating Spindle Error from Test BallRoundness Error[J]. CIRP Annals-Manufacturing Technology, 1971, 21.);

The method of the described calibration aided measurement of the flatness deviation z ₀ (θ _i ) of the auxiliary measurement surface of the cylinder 3 adopts the laser plane method (http://www.hamarlaser.com/), or the three-coordinate measurement method (see Advanced Technology 8, He Wenyan. Research on Measuring Flatness of Mechanically Polished Surfaces with Grazing Incident Structured Light [D]. Institute of Optoelectronic Technology, Chinese Academy of Sciences);

The method for the rotation tilt error T _x (θ _i ) of the described calibration precision rotary table 12, T _y (θ _i ) adopts the spindle rotation error separation method of multi-channel data acquisition; the synchronous tilt error T _x (θ _i ), T _y (θ _i ) is calculated by:

y ₁ (θ _i ) is the result of subtracting the roundness error h ₁ (θ _i ) of the auxiliary measuring surface of the auxiliary measuring cylinder in the upper section from the displacement measured by the precision displacement measuring sensor of the Y channel in the upper section; y ₂ (θ _i ) is the result of subtracting the roundness error h ₂ (θ _i ) of the auxiliary measuring surface of the auxiliary measuring cylinder in the lower section from the displacement measured by the precise displacement measuring sensor of the Y channel in the lower section.

The method for calibrating the axial runout error δz(θ _i ) of the precision rotary table 12 uses the displacement z(θ _i ) measured by the precise displacement measurement sensor of the Z channel minus the auxiliary measurement of the auxiliary measuring cylinder The flatness deviation z ₀ (θ _i ) of the surface; the method for calibrating the rotation radial runout error δx(θ _i ) adopts the separation method of the spindle rotation error of multi-channel data acquisition, the least squares of the upper section channel and the lower section channel Multiplying the center of the circle is O ₁ (a ₁ ,b ₁ ) and O ₂ (a ₂ ,b ₂ ), and the rotation synchronous radial runout error δx(θ _i ) is calculated by the following formula:

δ _x (θ _i )＝-l·T _y (θ _i )+(a ₂ -a ₁ )·cos(θ)+(b ₂ -b ₁ )·sin(θ)

The method for separating the eccentric error of rotating clamping is the best sinusoidal curve fitting method (see prior art 10, Zhou Jikun, Zhang Rong, Ling Mingxiang, Zhang Yi. High-precision machine tool spindle rotation error online test system [J]. China Test, 2016,42(07):64-67.), or frequency-domain Fourier transform filtering method (see prior art 11, Jamalian, A.(2010). A new method for characterizing spindle radial error motion: a two-dimensional point of view (T). University of British Columbia.).

Fig. 3 is the structure schematic diagram of another embodiment of the improved measuring device of conical mirror cylindrical mirror shape of the present invention, and Fig. 1 embodiment is different in that described measured optical element 4 is a concave aconic mirror, and the top of the concave aconical mirror The angle is greater than or equal to 90 degrees.

Fig. 4 is the structure schematic diagram of another embodiment of the improved measuring device of conical mirror cylindrical mirror shape of the present invention, and Fig. 1 embodiment is different, described tested optical element 4 is cylindrical mirror, and its generatrix and rotating The included angle α between the symmetry axes is 0°, and the range of the rotation angle of the cylindrical mirror is between 0° and 360°.

The advantage of the foregoing embodiment is that the measurement system has versatility, and can measure convex and concave conical mirrors with different calibers and different vertex angles, and can also measure cylindrical mirrors with different diameters and different rotation angle ranges. The measurement system is simple and low cost. lower. It can simultaneously measure the surface shape information of the component to be tested and the rotation error of the spindle of the precision rotary table, and remove the synchronous error and asynchronous error at the same time, and the measurement accuracy is higher.

Claims (9)

1. a measuring device of conical mirror cylindrical mirror shape, is characterized in that comprising wavefront measurement interferometer (1), interferometer support (2), precision rotary table (12) and turntable real-time measurement system; Described wavefront The measuring interferometer (1) is installed on the interferometer support (2); the described turntable real-time measuring system includes an auxiliary measuring cylinder (3) and 5 precision displacement measuring sensors; Described auxiliary measurement cylinder (3) is installed on the described precision rotary table (12), and the central axis of described auxiliary measurement cylinder (3) is in common with the rotation axis of described precision rotary table (12). Axis; said 5 precise displacement measurement sensors are respectively placed on the precision displacement measurement sensors of the z-axis direction, x-axis direction, and y-axis direction outside the described auxiliary measurement cylinder (3) ( 5), the precision displacement measurement sensor (6) of the X-channel displacement of the upper section and the precision displacement measurement sensor (8) of the X-channel displacement of the lower section, the precise displacement measurement sensor (7) of the Y-channel displacement of the upper section and the displacement of the Y-channel of the lower section The precise displacement measuring sensor (9), described upper section (10 and lower section (11) are two horizontal planes with a certain distance, and the vertical distance is denoted as 1; the upper surface of the described auxiliary measuring cylinder (3) Placement of the conical mirror or cylindrical mirror of the optical element (4) to be tested. 2. The conical mirror and cylindrical mirror surface shape measuring device according to claim 1, wherein the conical mirror is a convex aconic mirror, or a concave aconic mirror with an apex angle greater than or equal to 90 degrees; 3. conical mirror according to claim 1 and cylindrical mirror surface shape measuring device, it is characterized in that described wave surface measuring interferometer is the Fizeau interferometer with plane standard mirror, or Tieman Green interferometer, or Mach Zeider interferometer, or a point diffraction interferometer outputting a plane light wave, or a single interferogram measurement interferometer, or a dynamic measurement interferometer, or a high-speed dynamic measurement interferometer. 4. The device for measuring the shape of conical mirrors and cylindrical mirrors according to claim 1, wherein the interferometer bracket is a multi-dimensional adjustment bracket. 5. utilize the measuring method of tapered mirror and cylindrical mirror surface shape measuring device according to claim 1, it is characterized in that the method comprises the following steps: ① Establish the coordinate system of the detection system, take the direction of the rotation axis of the precision rotary table (12) as the Z direction, and the two orthogonal directions in the radial direction of the precision rotary table are respectively the X direction and the Y direction, and the busbar of the measured optical element (4) and The angle between the axes of rotational symmetry of the measured optical element is denoted as α, and the projection of the generatrix perpendicular to the outgoing light of the wave surface measuring interferometer on the XY plane coincides with the X axis; the range of the rotation angle of the precision rotary table is the same as the measured optical element The range of the rotation angle is the same; the rotation angle range of the precision rotary table is divided into N equal parts, recorded as θ _i , where i=1, 2, 3, ..., N, N is a positive integer, θ ₁ is the starting angle, and Corresponding to the starting position of the measured surface of the measured optical element; ② Calibrate the roundness error h(θ _i ) and flatness deviation z ₀ (θ _i ) of the auxiliary measuring surface of the auxiliary measuring cylinder (3); ③ Adjust the measuring device so that the wavefront measurement interferometer (1) observes the linear interferogram corresponding to a busbar of the measured optical element (4), the number of interference fringes is the least and the interference fringes are the widest, and the center position of the interference fringe area is measured by the measured Measure the busbar of the optical element, at this time, the center position of the interference fringe area is perpendicular to the outgoing light of the wave surface measuring interferometer; ④ Rotate the rotation angle θ of the precision rotary table (12) to θ ₁ , which is the starting angle position; 5. Use the wave surface measurement interferometer (1) to measure, and save the surface shape measurement result S(θ _i , w) of the centerline pixel of the effective area of the interferogram; Axial runout error δz(θ _i ), radial runout error δx(θ _i ), rotation inclination error T _x (θ _i ) in the X direction; w is the bus coordinates, w=0,1,2,...,W-1 , W is a positive integer, representing the pixel coordinates along the length direction of the busbar of the measured optical element; 6. Rotate the precision rotary table (12) to the next rotation angle position of the θ _i rotation angle, repeat step ₅ , until the measurement of all N rotation angle positions is completed; As the starting point, w=0,1,2,...,W-1, for the W group of surface shape measurement data S(θ _i ,w)(i=1,2,3,...,N), carry out the corresponding phase Phase unwrapping, so that the W group of surface shape measurement data S(θ _i ,w) are all continuous data; ⑦ According to the following formula (1), remove from S(θ _i ,w) the calibrated precision rotary table’s rotational axial runout error δz(θ _i ), rotational radial runout error δx(θ _i ), and rotational tilt error T _x (θ _i ) influence on the measurement results, F`(θ <sub>i</sub> ,w)=S(θ <sub>i</sub> ,w)-δz(θ <sub>i</sub> )·sin(α)-δx(θ <sub>i</sub> )·cos(α)-Tx(θ <sub>i</sub> )·w·PW, ( 1) Where PW is the width of each coordinate pixel corresponding to the bus coordinates; ⑧From F`(θ _i ,w), randomly select K groups with different generatrix coordinates w to remove the surface shape measurement data F`(θ <sub>i</sub> ,w <sub>k</sub> ), where i=1,2,3,..., N, k=1, 2, 3,..., K, according to the rotation clamping eccentricity error separation method, separate the F`(θ _i ,w _k ) detection error E(θ _i ,w _k ); the average value E(θ _i ) of K group E(θ _i ,w _k ) is: E(θ _i )＝(E(θ _i ,w ₁ )+E(θ _i ,w ₂ )+…+E(θ _i ,w _K ))/K, Remove the detection error E(θ _i ) caused by the installation eccentricity of the optical component under test from F`(θ <sub>i</sub> ,w), and obtain the surface shape detection result F(θ <sub>i</sub> ,w) of the optical component under test, F(θ <sub>i</sub> ,w)=F`(θ _i ,w)-E(θ _i ). 6. The measuring method according to claim 5, characterized in that the method of the roundness deviation h(θ _i ) of the auxiliary measuring surface of the auxiliary measuring cylinder adopts a multi-step method, a multi-point method, or reverse Law. 7. The measuring method according to claim 5, characterized in that the method for the flatness deviation z ₀ (θ _i ) of the auxiliary measuring surface of the auxiliary measuring cylinder adopts the laser plane method, the level method, or three coordinate measurement. 8. measuring method according to claim 5, it is characterized in that the rotation tilt error T _x (θ _i ) of described calibration precision rotary table, the method for T _y (θ _i ) adopts the spindle rotation error of multi-channel data acquisition Separation method; tilt errors T _x (θ _i ), T _y (θ _i ) are calculated by the following formula: y ₁ (θ _i ) is the result of subtracting the roundness error h ₁ (θ _i ) of the auxiliary measuring surface of the auxiliary measuring cylinder in the upper section from the displacement measured by the precision displacement measuring sensor of the Y channel in the upper section; y ₂ (θ _i ) is the result of subtracting the roundness error h ₂ (θ _i ) of the auxiliary measuring surface of the auxiliary measuring cylinder in the lower section from the displacement measured by the precise displacement measuring sensor of the Y channel in the lower section. 9. The measuring method according to any one of claims 5 to 8, characterized in that the method for calibrating the axial runout error δz(θ _i ) of the precision rotary table adopts the precision displacement measurement of the Z channel The displacement measured by the sensor z(θ _i ) minus the flatness deviation z ₀ (θ _{i )} of the auxiliary measuring surface of the auxiliary measuring cylinder; Spindle rotation error separation method, the least square centers of the upper channel and the lower channel are O ₁ (a ₁ , b ₁ ) and O ₂ (a ₂ , b ₂ ), respectively, and the rotational radial runout error δx(θ _i ) is passed through the lower channel formula calculation: δ _x (θ _i )＝-l·T _y (θ _i )+(a ₂ -a ₁ )·cos(θ)+(b ₂ -b ₁ )·sin(θ)