CN108362221A - A kind of free form surface pattern nano-precision detection method and device - Google Patents

Abstract

The invention belongs to the technical field of optical precision detection, and relates to a nanometer-precision profile measurement device and method for free-form surface parts, which can be used for nanometer-precision detection of free-form surface parts. The device includes: active air bearing vibration isolation spring, air bearing vibration isolation base, X direction air bearing guide rail, gantry frame, laser differential confocal fixed focus trigger measurement system, laser interference displacement measurement mirror group, Y direction air bearing guide rail , Z-direction air bearing guide rail, free-form surface sample attitude adjustment device, reference flat crystal attitude adjustment device, laser interferometer; using the profile measurement method of the gantry structure three-coordinate measuring machine, combined with high-precision flat crystal as the reference mirror, reducing X The influence of the straightness of the air-bearing guideway in the direction and Y direction on the high-precision detection of the surface contour of the free-form surface, thereby reducing the 21 errors of the three-coordinate measuring machine. A spherical air-floating workbench with a three-point support structure is used to adjust the attitude of the free-form surface parts to be tested to achieve high-precision detection of the contour of the free-form surface parts.

Description

Nano-precision detection method and device for free-form surface morphology

technical field

The invention belongs to the technical field of optical precision detection, and relates to a high-precision detection method and device for free-form surface topography, which can be used for nano-precision detection of free-form surface topography in precision optical systems.

technical background

The free-form surface element has the largest degree of freedom in surface morphology, and it is easy to eliminate aberrations in the imaging system. It can greatly improve the imaging quality and resolution of the measurement optical system, and improve the performance of weapons and equipment; use the free-form surface optical system to replace the previous optical system composed of plane, spherical mirror, coaxial quadric mirror, etc. to improve Imaging quality, reducing the volume and weight of the system, and then solving the problems of imaging accuracy, portability and reliability have become an important trend in the development of optical systems.

However, while the freeform surface increases the design freedom, it puts forward higher requirements for design, processing and testing. With the successful application of optical CAD and numerical control diamond point processing technology in optical design and manufacturing, the design and Processing is no longer the main technical obstacle, but the measurement problem is increasingly becoming a difficult problem to be solved urgently. The processing accuracy of the free-form surface shape by optical diamond point processing technology mainly depends on the measurement accuracy of the spatial coordinates of each point on the surface. Therefore, whether the component surface shape can meet the design requirements must be guaranteed by high-precision detection technology.

At present, the surface profile measurement methods of free-form surfaces in the world can be mainly divided into three categories: light field image measurement method, tomographic scanning detection method and probe three-dimensional scanning detection method. The image detection method does not need to scan the sample during the measurement process, and the measurement speed is fast, but it cannot adapt to the high-precision measurement of free-form surfaces with arbitrary inclination angle changes, and is easily affected by differences in the characteristics of the sample surface such as reflectivity and roughness. The principle of the tomographic scanning method is simple, but there are certain restrictions on the size and material of the measured parts and high requirements on the operating environment. The measurement accuracy of existing instruments is 1-10mm, and the measurement accuracy is low. The probe three-dimensional scanning measurement method uses the probe to locate the surface of the free-form surface sample point by point, and obtains the surface morphology of the sample by measuring the coordinate reconstruction of each position point. Usually, the probe or the sample is driven by a coordinate measuring machine for detection. At present, Due to the advantages of high measurement accuracy and wide application range, this method has gradually become the mainstream technology for free-form surface measurement.

The traditional probe three-dimensional scanning measurement methods include: contact probe method, sharpness method, time-of-flight method and confocal positioning method. The contact probe method has high measurement accuracy, good reliability and stability, but the obtained measurement data needs to be compensated according to the shape of the probe head, and because there is a contact force in the measurement, it cannot be used for soft, fragile, etc. The sample is measured and may scratch the polished sample surface. The sharpness method uses digital image processing technology to judge the imaging quality of the optical system, and finds the point with the clearest imaging as the fixed-focus position. However, due to the obvious limitation of diffraction, the sensitivity of aiming and positioning is low, and the accuracy fluctuates between 1% and 2 %, the positioning accuracy is only on the order of microns. The measurement principle of the time-of-flight method is simple and does not require image processing, but the resolution is low, and the measurement accuracy is about 20-50mm, which is not suitable for precision measurement environments. The sensitivity of the interferometric method is very high, and the theoretical limit of its axial positioning can reach 1nm, but it has strict requirements on the measurement environment, and is easily affected by differences in characteristics such as the inclination angle and roughness of the sample surface, and its practical engineering application is greatly restricted. The confocal method has high focal precision, strong anti-environmental interference ability, and has a certain ability to suppress the influence of sample surface property differences, and the axial positioning resolution can reach 200nm.

In summary, the existing measurement methods mainly have insufficient measurement accuracy, which cannot overcome the influence of sample surface roughness, undulation, inclination and other characteristic differences, which is the main bottleneck that currently limits the measurement accuracy of free-form surface contours. Based on the above situation, the present invention proposes a new normalized laser differential confocal high-precision fixed-focus trigger measurement method that is resistant to surface inclination changes and anti-scattering changes. The plane flat crystal is used as the reference plane of the X-Y plane, and the straightness error of the X-direction and Y-direction air bearing guide rail is monitored and compensated by the laser interferometer, so as to realize the separation of the dimensionality reduction error of the free-form surface topography, thereby realizing the nanometerization of the free-form surface topography Accuracy detection.

The core idea of the patent of the present invention is to use a high-precision flat crystal as the reference plane of the X-Y plane, monitor and compensate the straightness error of the X-direction and Y-direction air bearing guide rail through the laser interferometer, and realize the dimensionality reduction error of the free-form surface shape Separation, and through the new method of normalized laser differential confocal high-precision fixed-focus trigger measurement that resists surface inclination changes and anti-scattering changes, conducts nano-precision fixed-focus trigger measurement of free-form surface topography, combined with residual gas recovery air-floating guide rails The macro-micro cross-scale nano-precision non-disturbance driving and positioning method provides high-precision three-dimensional linear positioning and scanning measurement means for free-form surface shape detection, and uses the linear segment of the differential confocal curve to directly measure the sample to reduce focus tracking requirements , which can perform rapid nanometer-precision measurement of free-form surface topography with fine structures.

Contents of the invention

The purpose of the present invention is to improve the detection accuracy and efficiency of free-form surface topography, overcome the deficiencies of the prior art, and propose a free-form surface topography nano-precision detection method and device thereof.

The present invention is based on the residual air recovery type air bearing guide rail invented by us, the decoupling and undisturbed drive and positioning method of macro-micro-span nano-precision motion error to realize nano-precision three-dimensional scanning and positioning; large-scale tilt adjustment based on aerostatic bearing technology Self-aligning technology realizes attitude adjustment of free-form surface samples, ensuring that the inclination angle of any point is within the measurable range of the system; high-precision flat crystals are used in the Z direction for nanometer-precision laser interference displacement measurement, reducing the straight line of the air bearing guide rail in the X and Y directions The influence of degree on free-form surface profile measurement improves the accuracy of Z-direction laser differential confocal fixed-focus trigger detection, and realizes the nano-precision detection of free-form surface topography.

The purpose of the present invention is achieved through the following technical solutions.

The nano-accuracy detection method of the free-form surface morphology of the present invention comprises the following steps:

Step 1: Place the high-precision flat crystal on the free-form surface sample attitude adjustment device and the reference flat crystal attitude adjustment device, measure the distance between the laser interferometry mirror group and the high-precision flat crystal by laser interferometer, and adjust the free-form surface The attitude of the sample attitude adjustment device and the reference flat crystal attitude adjustment device is guaranteed to be perpendicular to the Z-direction air bearing guide rail;

Step 2: Place the measured free-form surface sample and high-precision flat flat crystal on the free-form surface sample attitude adjustment device and the reference flat crystal attitude adjustment device respectively, and use the Z-direction air bearing guide to drive the laser differential confocal fixed-focus trigger measurement The system and the laser interferometric displacement measurement mirror group move along the Z direction, and obtain the Z-direction surface height and inclination angle information of the measured free-form surface topography according to the obtained laser differential confocal response curve;

Step 3: Use the X-direction air-floating guide rail to move the air-floating guide sleeve at equal intervals in the X direction, and repeat step 2 for each measurement point. When the laser differential confocal response of the trigger measurement system is weak, by adjusting the attitude adjustment device of the free-form surface sample, ensure that the inclination angle of any point on the free-form surface sample is within the measurable range, and realize the X-direction scanning detection of the free-form surface topography ;

Step 4: Every time the X-direction scanning detection of the free-form surface morphology is completed, use the Y-direction air bearing guide rail to move one step at equal intervals along the Y direction, and repeat step 3 to realize the Y-direction scanning detection of the free-form surface morphology;

Step 5: The linear motion error of the measured free-form surface sample in the X-direction and Y-direction scanning detection is compensated by the displacement data measured by the laser interferometer, and the three-dimensional shape data of the free-form surface sample {D ₁₁ (x,y,z ),D ₁₂ (x,y,z),…,D ₁₂ (x,y,z),D _ij (x,y,z),…,D _MN (x,y,z)} fitting, get The overall surface profile of the free-form surface sample to be tested is used to solve the polynomial characterizing the surface profile of the free-form surface, and to realize the nano-precision detection of the free-form surface topography.

The free-form surface topography nano-precision detection device of the present invention includes: active air-flotation vibration isolation spring, air-flotation vibration isolation base, X-direction air-flotation guide rail, gantry, laser differential confocal fixed-focus trigger measurement system, laser interference Displacement measurement mirror group, Y-direction air bearing guide rail, Z-direction air bearing guide rail, free-form surface sample attitude adjustment device, reference flat crystal attitude adjustment device, laser interferometer.

The present invention adopts the contour measurement method of the three-coordinate measuring machine with the gantry structure, wherein the air-floating vibration-isolation base is installed on the active air-flotation vibration-isolation spring, and the active air-flotation vibration-isolation spring plays the role of vibration isolation; the X-direction air The floating guide rail is fixedly installed on the air-floating vibration isolation base, and the air-floating guide sleeve is installed on the X-direction air-floating guide rail, and the free-form surface sample attitude adjustment device and the reference flat crystal attitude adjustment device are installed in parallel on the On the air bearing guide sleeve; the laser differential confocal fixed-focus trigger measurement system and the laser interferometric displacement measurement mirror group are installed in parallel on the Z-direction air bearing guide rail, the Z-direction air bearing guide rail is installed on the Y-direction air bearing guide rail, and the Y-direction air bearing guide rail is installed on the Y-direction air bearing guide rail. The guide rail and the laser interferometer are respectively installed on the gantry frame, and the gantry frame is fixedly installed on the air-floating shock-isolation base.

Beneficial effect

Compared with the prior art, the present invention has the following significant advantages:

1) The free-form surface three-dimensional measurement method using high-precision flat crystal as the X-Y reference plane greatly reduces the influence of the straightness error of the X- and Y-guided rails on the sensitive direction of the Z-direction measurement of the free-form surface. Theoretically, the free-form surface can be The scanning detection accuracy of the surface is improved to within 50nm;

2) A new normalized laser differential confocal high-precision fixed-focus trigger measurement method that resists surface inclination changes and anti-scattering changes can realize high-precision axial fixed-focus trigger detection on free-form surfaces with surface inclination changes of up to 25°, and It can improve the detection accuracy and speed of free-form surface topography;

3) The attitude adjustment device of the spherical air-floating free-form surface sample based on the design of the three-point support structure can adjust the attitude of the measured free-form surface sample through piezoelectric ceramics. According to the range of the selected piezoelectric ceramic, the measured free-form surface shape The measuring range is increased up to 45°;

4) The nanometer-accurate three-dimensional scanning driving positioning method based on motion error decoupling and undisturbed driving technology can realize nanoscale feed resolution and positioning in a moving range greater than 100mm, and can carry out free-form surface samples in the X and Y directions The accuracy of scanning detection is improved from 2μm to 0.6μm.

Description of drawings

Fig. 1 is a schematic diagram of the free-form surface topography nano-accuracy detection device and method of the present invention;

Fig. 2 is a schematic diagram of the laser differential confocal fixed-focus trigger measurement principle of the present invention;

3 is a schematic diagram of the scanning detection path in the X-Y plane of the free-form surface topography nano-precision detection device and method of the present invention;

Fig. 4 is a schematic diagram of a free-form surface sample attitude adjustment device in the free-form surface topography nano-precision detection device and method of the present invention;

Numbers in the figure, 1-active air-floating vibration isolation spring, 2-air-floating guide rail, 3-serpentine drive X-direction air-floating guide rail, 4-gantry frame, 5-laser differential confocal fixed-focus trigger measurement system, 6- Measuring laser interferometry mirror group, 7-Y-direction air bearing guide rail, 8-Z-direction air bearing guide rail, 9-sample attitude adjustment device, 10-reference flat crystal attitude adjustment device, 11-laser interferometer, 12-laser differential Confocal response curve zero crossing point, 13-laser differential confocal response curve approximate linear segment, 14-measurement point, 15-support point.

Detailed ways

The present invention will be further described below in conjunction with drawings and embodiments.

The nano-accuracy measurement method of the free-form surface shape of the present invention includes that the Z-direction air-floating guide rail drives the laser differential confocal fixed-focus trigger measurement system and the laser interference displacement measurement mirror group to move, and the differential confocal signal intensity changes accordingly, and the difference is obtained. Dynamic confocal response curve, using the characteristic that the "zero crossing point" of the differential confocal response curve precisely corresponds to the focal position of the laser differential confocal fixed focus trigger measurement system, and accurately captures the laser differential confocal fixed focus through the "zero crossing point" Trigger the focus of the measurement system to realize the nano-precision measurement of the free-form surface shape; the movement of the laser interferometric displacement measurement mirror group will change the displacement measurement results of the high-precision flat crystal placed on the reference flat crystal attitude adjustment device, and the high-precision The plane flat crystal is used as the reference mirror for Z-direction laser interferometric displacement measurement. By processing the displacement measurement results of the laser interferometer, the influence of the straightness of the X-direction air-bearing guide rail and the Y-direction air-bearing guide rail on the Z direction of the free-form surface topography sensitive measurement is reduced; Secondly, use the X-direction air bearing guide rail to drive the movement of the free-form surface sample attitude adjustment device and the reference flat crystal attitude adjustment device to realize the X-direction scanning measurement of the free-form surface sample, and use the Y-direction air bearing guide rail 7 to drive the Z-direction air bearing guide rail to move along the Y direction , to realize the Y-direction scanning surface measurement of the free-form surface sample; finally, according to the measured surface profile data of several free-form surface samples, reverse modeling is carried out to fit the surface profile of the free-form surface sample to realize the nanoscale measurement of the free-form surface topography Accuracy detection.

Based on the nano-accuracy detection method of the free-form surface topography described in the present invention, a nano-precision detection device for the free-form surface topography as shown in FIG. 1 is constructed.

Example 1

As shown in Figure 1 and Figure 2, the device of the present invention includes: active air-floating vibration isolation spring, air-floating vibration-isolation base, X-direction air-floating guide rail, gantry, laser differential confocal fixed-focus trigger measurement system, laser Interference displacement measurement mirror group, Y-direction air bearing guide rail, Z-direction air bearing guide rail, free-form surface sample attitude adjustment device, reference flat crystal attitude adjustment device, laser interferometer;

The nano-precision detection method of free-form surface morphology, the detection steps are as follows:

Step 1: Place the high-precision flat crystal on the free-form surface sample attitude adjustment device 9 and the reference flat crystal attitude adjustment device 10 respectively, and measure the distance between the laser interferometer mirror group 6 and the high-precision flat crystal through the laser interferometer 11 , adjust the attitudes of the free-form surface sample attitude adjustment device 9 and the reference flat crystal attitude adjustment device 10 to ensure that they are perpendicular to the Z-direction air bearing guide rail 8;

Step 2: Place the measured free-form surface sample and the high-precision flat flat crystal on the free-form surface sample attitude adjustment device 9 and the reference flat crystal attitude adjustment device 10 respectively, and use the Z-direction air bearing guide rail 8 to drive the laser differential confocal positioning. The focal trigger measurement system 5 and the laser interferometric displacement measurement mirror group 6 move along the Z direction, and the zero-crossing point 12 of the laser differential confocal response curve is obtained according to the approximate linear segment 13 of the laser differential confocal response curve and the displacement information measured by the laser interferometer 11 , so as to obtain the surface height and inclination information of the measured free-form surface topography in the Z direction;

Step 3: As shown in Figure 3, drive the X-direction air-floating guide rail 3 and the Y-direction air-floating guide rail 7 along the serpentine, repeat step 2 for each measurement point 14, and collect the surface height and inclination angle information of each measurement point 14 to realize X-Y plane scanning detection of free-form surface morphology;

Step 4: The linear motion error of the measured free-form surface sample during X-direction and Y-direction scanning detection is compensated by the displacement data measured by the laser interferometer 11, and the three-dimensional shape data of the free-form surface sample {D ₁₁ (x, y, z),D ₁₂ (x,y,z),…,D ₁₂ (x,y,z),D _ij (x,y,z),…,D _MN (x,y,z)} fitting, The overall surface profile of the free-form surface sample to be tested is obtained, and the characterization polynomial of the free-form surface profile is solved to realize the nanometer-precision detection of the free-form surface morphology.

Example 2

As shown in Fig. 1, Fig. 2, Fig. 3 and Fig. 4, the nano-precision detection method of free-form surface morphology, the detection steps are as follows:

Step 1: Place the high-precision flat crystal on the free-form surface sample attitude adjustment device 9 and the reference flat crystal attitude adjustment device 10 respectively, and measure the distance between the laser interferometer mirror group 6 and the high-precision flat crystal through the laser interferometer 11 , adjust the attitudes of the free-form surface sample attitude adjustment device 9 and the reference flat crystal attitude adjustment device 10 to ensure that they are perpendicular to the Z-direction air bearing guide rail 8;

Step 2: Place the measured free-form surface sample and the high-precision flat flat crystal on the free-form surface sample attitude adjustment device 9 and the reference flat crystal attitude adjustment device 10 respectively, and use the Z-direction air bearing guide rail 8 to drive the laser differential confocal positioning. The focal trigger measurement system 5 and the laser interferometric displacement measurement mirror group 6 move along the Z direction, and obtain the Z-direction surface height and inclination information of the measured free-form surface topography according to the laser differential confocal response curve and the displacement information measured by the laser interferometer 11 ;

Step 3: When the surface inclination angle of the free-form surface sample to be measured is relatively large, resulting in a weak laser differential confocal response light intensity of the laser differential confocal fixed-focus trigger measurement system 5, as shown in Figure 4, send the signal through the vertical minimum area. To determine the attitude, use the piezoelectric ceramics located at the support point 15 to adjust the attitude of the spherical air-floating workbench, so that the inclination angle of the free-form surface sample to be measured is within the measurable range of the system, and drive the X-direction air-floating guide rail 3 and Y along the serpentine To the air bearing guide rail 7, repeat step 2 for each measurement point 14, collect the surface height and inclination angle information of each measurement point 14 to realize the X-Y plane scanning detection of the free-form surface morphology;

Step 4: The linear motion error of the measured free-form surface sample during X-direction and Y-direction scanning detection is compensated by the displacement data measured by the laser interferometer 11, and the three-dimensional shape data of the free-form surface sample {D ₁₁ (x, y, z),D ₁₂ (x,y,z),…,D ₁₂ (x,y,z),D _ij (x,y,z),…,D _MN (x,y,z)} fitting, The overall surface profile of the free-form surface sample to be tested is obtained, and the characterization polynomial of the free-form surface profile is solved to realize the nanometer-precision detection of the free-form surface morphology.

The specific embodiment of the present invention has been described above in conjunction with the accompanying drawings, but these descriptions can not be interpreted as limiting the scope of the present invention, the protection scope of the present invention is defined by the appended claims, any claims on the basis of the present invention The changes made are within the protection scope of the present invention.

Claims (9)

1. a kind of Free-form Surface Parts profile nano-precision detection method, it is characterised in that include the following steps：

Step 1：High precision plane optical flat is respectively placed in free form surface sample device for adjusting posture (9) and refers to optical flat posture In adjusting apparatus (10), measured between laser interferometry microscope group (6) and high precision plane optical flat by laser interferometer (11) Distance, adjustment free form surface sample device for adjusting posture (9) and the posture with reference to optical flat device for adjusting posture (10), guarantee and Z It is vertical to air-float guide rail (8)；

Step 2：Tested free form surface sample and high precision plane optical flat are individually positioned in free form surface sample pose adjustment dress It sets on (9) and with reference on optical flat device for adjusting posture (10), drives laser differential confocal fixed-focus to touch using Z-direction air-float guide rail (8) Hair measuring system (5) and laser interferometer displacement measure microscope group (6) and are moved along Z-direction, approximate according to laser differential confocal response curve The displacement information that linearity range (13) and laser interferometer (11) measure obtains laser differential confocal response curve zero crossing (12), from And obtain the Z-direction apparent height and obliquity information for being tested free form surface sample profile；

Step 3：When tested free form surface sample surfaces inclination angle is larger, laser differential confocal fixed-focus is caused to trigger measuring system (5) Laser differential confocal response light intensity it is weaker when, by longitudinal minimum area method carry out pose discrimination, using positioned at supporting point (15) piezoelectric ceramics adjusts the posture of spherical surface air-flotation workbench, makes the inclination angle of tested free form surface sample that can survey model in system In enclosing, drives X to air-float guide rail (3) and Y-direction air-float guide rail (7) along serpentine path, step 2 is repeated to each measurement point (14), Acquire the apparent height of each measurement point (14) and the X-Y plane scanning inspection of obliquity information realization free form surface sample profile It surveys；

Step 4：Tested free form surface sample carry out X to straight-line motion accuracy when Y-direction Scanning Detction by laser interferometer (11) it measures obtained displacement data to compensate, by free form surface sample three-dimensional appearance data { D₁₁(x,y,z),D₁₄(x,y, z),…,D₁₄(x,y,z),D_ij(x,y,z),…,D_MN(x, y, z) } fitting, obtain the integral face type wheel of tested free form surface sample Exterior feature solves the characterization multinomial of free form surface surface profile, realizes the nano-precision detection of Free-form Surface Parts profile.

2. a kind of Free-form Surface Parts profile nano-precision detection method according to right 1, it is characterised in that：Using high-precision Reference datum of the plane-parallel crystal as X-Y plane is spent, X is monitored and compensated by laser interferometer (11) to air-float guide rail (3) and Y To the straightness error of air-float guide rail (7), free form surface pattern error dimensionality reduction is made to detach, realizes the nanometer essence of free form surface pattern Degree detection.

3. a kind of Free-form Surface Parts profile nano-precision detection method according to right 1, which is characterized in that use anti-table Face change of pitch angle and the normalization laser differential confocal high-precision fixed-focus of anti-scattering variation trigger new method of measuring, realize that surface is inclined Angle variation realizes the nanometer essence of Free-form Surface Parts profile up to 45 ° of free form surface high-precision surface axial direction fixed-focus detection trigger Degree detection.

4. a kind of Free-form Surface Parts profile nano-precision detection method according to claim 1, which is characterized in that use It normalizes laser differential confocal high-precision fixed-focus and triggers measurement method, directly utilize laser differential confocal response curve approximately linear Section (13) quickly measures sample topography, reduces Focus tracking requirement, improves free-float space robot efficiency, realizing has fine knot The free form surface pattern of structure quickly measures.

5. a kind of Free-form Surface Parts profile nano-precision detection method according to claim 1, which is characterized in that be based on The spherical surface air supporting free form surface sample device for adjusting posture (9) of three-point support structure design, is adjusted by piezoelectric ceramics and is tested certainly By the posture of curved surface sample, the measurement range for being tested free form surface sample profile is improved.

6. a kind of Free-form Surface Parts profile nano-precision detection device, using the profile measurement of gantry structure three coordinate measuring machine Mode, it is characterised in that including：Active air supporting shock insulation spring (1), air supporting vibration isolation pedestal (2), X are to air-float guide rail (3), portal frame (4), laser differential confocal fixed-focus triggering measuring system (5), laser interferometer displacement measure microscope group (6), Y-direction air-float guide rail (7), Z To air-float guide rail (8), free form surface sample device for adjusting posture (9), with reference to optical flat device for adjusting posture (10), laser interferometer (11)；Wherein, air supporting vibration isolation pedestal (2) is mounted on active air supporting shock insulation spring (1), passes through active air supporting vibration isolation spring (1) Play the role of vibration isolation；X is fixedly mounted on to air-float guide rail (3) on air supporting vibration isolation pedestal (2), X pacifies on air-float guide rail (3) Equipped with air supporting guide sleeve, and three-point support structure design free form surface sample device for adjusting posture (8) will be based on and refer to optical flat appearance State adjusting apparatus (9) is installed in parallel on air supporting guide sleeve；Laser differential confocal fixed-focus triggers measuring system (5) and laser interference position Shift measurement microscope group (6) is installed in parallel on Z-direction air-float guide rail (8), and Z-direction air-float guide rail (8) is mounted on Y-direction air-float guide rail (7), Y It is separately mounted on portal frame (4) to air-float guide rail (7) and laser interferometer (11), portal frame is fixedly mounted on air supporting shock insulation base On seat (2).

7. a kind of Free-form Surface Parts profile nano-precision detection device according to claim 6, it is characterised in that：It will be high Precision face optical flat is as X-Y reference data plane devices, by adjusting free form surface sample device for adjusting posture (9) and reference The posture of optical flat device for adjusting posture (10) is vertical with Z-direction air-float guide rail (8), can effectively inhibit X to air-float guide rail (3) and The straightness error of Y-direction air-float guide rail (7) realizes X-Y plane straightness dimensionality reduction error separate, improves the survey of free form surface pattern Accuracy of measurement.

8. a kind of Free-form Surface Parts profile nano-precision detection device according to claim 6, which is characterized in that this dress The Free-form Surface Parts profile surface sweeping mode set includes：Simple scan and Single Slice Mode；Simple scan utilizes laser differential confocal Fixed-focus triggers measuring system (5) and carries out the triggering measurement of single-point fixed-focus；Single Slice Mode is measured using the triggering of laser differential confocal fixed-focus The characteristic of the differential confocal curve linear section of system (5) reduces Focus tracking requirement, to the direct laminar analysis measurement of sample.

9. a kind of Free-form Surface Parts profile nano-precision detection method according to claim 6, it is characterised in that：It will be remaining Gas recovery type air-float guide rail technology, big stroke lead screw actuation techniques, nanoscale Piezoelectric Ceramic technology, laser interference length-measuring skill Art and unperturbed connector technological incorporation are realized macro-micro- across scale nanometer precision unperturbed driving and are measured, height is provided for free form surface 3 d-line positioning and the scanning survey means of precision.