An optical-mechanical component surface shape in-situ detection device and method

Abstract

The present invention discloses an in-situ detection device and method for the surface shape of an optical-mechanical component, which belongs to the field of optical precision detection technology, and aims to solve the problem in the prior art that there is a lack of in-situ monitoring and detection of surface shape distortion during the adjustment process of an optical-mechanical component. The laser light generated by the laser in the device is incident on the optical-mechanical component to be measured after passing through a beam isolator, a beam splitter prism, and a collimator A in sequence, and is reflected. The reflected light of the optical-mechanical component to be measured is incident on the beam splitter prism after passing through the collimator A and is reflected. The reflected light of the beam splitter prism is incident on a CCD camera after passing through a perforated light screen, a collimator B, and a phase plate. The CCD camera is connected to a computer system, and the light spot diagram recorded by the CCD camera will be input into the computer system for in-situ detection of the surface shape. The method modulates the reflected light of the sample to be measured by a phase plate, and uses a phase reconstruction algorithm based on light field diffraction iteration to realize sample surface shape reconstruction. It has the advantages of high measurement accuracy, no need for a reference plane, and strong vibration resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical precision detection, and relates to a method and device for reconstructing phase using diffraction spots, and in particular to an on-site detection device and method for the surface shape of an optomechanical component, which is used for on-site measurement of surface shape distortion during the precision assembly and calibration of an optomechanical component. Background Art

[0002] In large-scale laser inertial confinement fusion devices and some other large-scale optical projects, there are some large-volume, ton-level optomechanical components. Large-caliber optomechanical components are one of the key components of large optical systems. These optomechanical components need to meet the requirements of sub-millimeter position installation accuracy and sub-milliradian pointing accuracy, so these optical components need to go through a precision assembly and calibration stage before being put on the shelf.

[0003] For the precision calibration of optical components, the invention patent application with application number 202110389594.X discloses a precision installation and adjustment method for ton-level optomechanical components, which includes the following steps: S1. After the optomechanical component enters the installation station, the external target of the optomechanical component is tested by a coordinate measuring device to obtain the actual measured position of the optomechanical component; S2. The target position of the optomechanical component is obtained by fitting the actual measured position with the theoretical position, and the adjustment amount is calculated; S3. According to the six-degree-of-freedom positioning principle of the object, the adjustment amount is converted into at least 6 independent quantities, and the at least 6 independent quantities are used as the adjustment amount. The vertical amount includes Z-adjustment amount, X-adjustment amount and Y-adjustment amount, which are adjusted according to the converted independent amounts; the X-direction and Y-direction of the optical-mechanical assembly are adjusted by an adjustment tool, the adjustment tool includes an adjustment sheet, a limit block and a fixed block, the adjustment sheet is fitted with the side of the optical-mechanical assembly support device, the limit block is fitted with the other side of the adjustment sheet, the limit block is fixed by a fixing part, and the fitting surface of the limit block and the adjustment sheet is the adjustment target surface of the optical-mechanical assembly in the X-direction or the Y-direction; the Z-direction of the optical-mechanical assembly is adjusted by a gasket, and the thickness of the gasket is the Z-direction adjustment amount.

[0004] The above-mentioned precision installation and adjustment method realizes the precise positioning of the optical-mechanical components, which not only improves the adjustment efficiency but also ensures the positioning accuracy. However, in this stage, the preload of the screws or fasteners will cause different degrees of local stress in the optical elements, resulting in additional wavefront distortion in the local area of ​​the optical elements, which ultimately affects the output wavefront quality of the laser. When the additional wavefront distortion is too large, it will not only cause the laser focusing spot to block the hole, affect the uniform distribution of the laser beam and cause self-condensation damage; it will also affect the beam focusing performance, causing subsequent optical elements to be damaged due to energy concentration. Therefore, in order to ensure the safe and stable operation of optical elements, it is necessary to strictly control the surface distortion of optical elements after precise assembly and calibration. It can be seen that in the precise assembly and calibration stage, the deterministic loading of the preload after the optical element is installed in the special tooling is the key to ensure the precise control of the wavefront quality of the optical element when it is in service.

[0005] Due to the lack of in-situ detection capability of the surface shape during the assembly and adjustment of optical-mechanical components, it is difficult to achieve deterministic control of the preload force during the assembly and adjustment process by relying solely on the experience of precision assembly and adjustment workers, which limits the further improvement of the precision assembly and adjustment process. Therefore, there is an urgent need for a detection device and method for in-situ monitoring of the surface shape distortion of components under the loading of preload force during the assembly and adjustment process, so as to meet the detection needs of the surface shape distortion of optical-mechanical components during the assembly and adjustment process. Summary of the invention

[0006] The purpose of the present invention is to solve the problem in the prior art of lack of in-situ monitoring and surface distortion detection of optical-mechanical components during assembly and adjustment, and to provide an in-situ surface distortion detection device and method for optical-mechanical components.

[0007] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0008] An in-situ detection device for the surface shape of an optical-mechanical component comprises a laser, a beam isolator, a beam splitter, a collimator A, an optical-mechanical component to be measured, a light screen with holes, a collimator B, a phase plate, a CCD camera, and a computer system;

[0009] The laser generated by the laser passes through the beam isolator, the beam splitter prism, and the collimator A in sequence, and then is incident on the optical machine component to be measured and reflected. The reflected light of the optical machine component to be measured passes through the collimator A and then is incident on the beam splitter prism and reflected. The reflected light of the beam splitter prism passes through the perforated light screen, the collimator B, and the phase plate and then is incident on the CCD camera; the CCD camera is connected to the computer system, and the light spot pattern recorded by the CCD camera will be input into the computer system for in-situ surface shape detection.

[0010] Furthermore, the laser and the light screen with holes are both located at the focal position of the collimator A.

[0011] Furthermore, the collimator A and the collimator B are placed confocally, and the focal length ratio of the collimator A and the collimator B is 8.

[0012] Furthermore, the splitting ratio of the beam splitter prism is 1:1.

[0013] Furthermore, the wavelength of the laser output by the laser is 632.8 nm, the diameter of the central hole of the perforated light screen is 2 mm, and the distance between the phase plate and the target surface of the CCD camera is 20 mm.

[0014] Furthermore, the substrate of the phase plate is made of fused quartz, and the size of the substrate is φ25.4 mm×1.5 mm;

[0015] The effective aperture of the phase modulation region of the phase plate is 15 mm, the phase modulation cells in the phase modulation region are randomly distributed, and the size of the phase modulation cells is 20 μm;

[0016] The phase plate is fabricated by photolithography, with a duty ratio of 0.5 and an optical path difference of 130 nm between the etched area and the non-etched area.

[0017] A method for detecting the surface shape of an optical-mechanical component in place, comprising the above-mentioned device for detecting the surface shape of an optical-mechanical component, wherein when the device for detecting the surface shape of an optical-mechanical component is used for detection, the specific steps are as follows:

[0018] Step 1, the laser emits laser, adjusts the posture of the optical-mechanical component surface shape in-situ detection device, and the laser passes through the beam isolator, the beam splitter, the collimator A, the optical-mechanical component to be measured, the collimator A, the beam splitter, the perforated light screen, the collimator B, the phase plate, and the CCD camera in sequence, and generates a diffraction spot on the CCD camera;

[0019] Step 2: Collect and save the diffraction spots corresponding to different image plane coordinates of the CCD camera ,in is the image plane coordinate;

[0020] Step 3: Use the complex amplitude of the phase plate , diffraction spot Iterate the surface shape of the optical machine component to be measured; the specific iteration steps are:

[0021] Step 1, the laser emits laser, adjusts the posture of the optical-mechanical component surface shape in-situ detection device, and the laser passes through the beam isolator, the beam splitter, the collimator A, the optical-mechanical component to be measured, the collimator A, the beam splitter, the perforated light screen, the collimator B, the phase plate, and the CCD camera in sequence, and generates a diffraction spot on the CCD camera;

[0022] Step 2: Collect and save the diffraction spots corresponding to different image plane coordinates of the CCD camera ;

[0023] Step 3: Complex amplitude of the light field using the phase plate , diffraction spot Iterate the surface shape of the optical machine component to be measured; the specific iteration steps are:

[0024] Step 3-1, giving the optical machine component 105 to be tested an initial randomly guessed light field complex amplitude ;

[0025] Step 3-2, support domain constraint S: refers to the constraint on the optical machine component to be measured, which is used to limit the size and position of the light field complex amplitude distribution area of ​​the optical machine component to be measured 105:

[0026] ;

[0027] Step 3-3, the complex amplitude of the limited light field Transmitted to the phase plate, and the incident light field complex amplitude of the phase plate is obtained respectively , complex amplitude of the outgoing light field :

[0028] ;

[0029] ;

[0030] Step 3-4: Reconstruct the phase plate's outgoing light field into complex amplitude Transmitted to the CCD camera to obtain the complex amplitude of the light field of the CCD camera :

[0031] ;

[0032] Step 3-5, using the CCD camera to collect the diffraction spot Complex amplitude of light field To perform a modulus constraint:

[0033] ;

[0034] Step 3-6: The constrained light field complex amplitude Transmitted back to the phase plate to obtain the updated complex amplitude of the output light field of the phase plate , update the complex amplitude of the incident light field :

[0035] ;

[0036] ;

[0037] Step 3-7 will update the complex amplitude of the incident light field Transmit back to the optical machine component to be measured, and update the light field complex amplitude of the optical machine component to be measured, so as to obtain the updated light field complex amplitude of the optical machine component to be measured :

[0038] ;

[0039] ;

[0040] Step 3-8, repeat steps 3-1 to 3-7 until the loop termination condition is met and the iteration is completed;

[0041] in, represents the image plane coordinates in the CCD camera, Represents the image plane coordinates of the phase plate and the optical machine component to be measured, represents the support domain, represents the diffraction transmission operation, represents the complex conjugate of the complex amplitude of the light field of the phase plate, represents the inverse diffraction transmission operation, Represents the complex amplitude of the light field transmitted back to the optical component to be measured.

[0042] Furthermore, in step 3-8, the loop termination condition is: when When it is less than the requirement of the convergence criterion, the iteration loop is jumped out;

[0043] ;

[0044] Where N is the total number of iterations, represents the beam amplitude distribution on the image plane of the CCD camera at the nth iteration, Represents the diffraction spot collected by the CCD camera.

[0045] The beneficial effects of the present invention are as follows:

[0046] In the present invention, a phase plate is used to modulate the measuring light field to obtain the diffraction spot information of the optical-mechanical component to be measured with strong phase modulation, and then a phase reconstruction algorithm based on square diffraction iteration is used to realize the surface reconstruction and in-situ detection of the optical-mechanical component. Compared with other interference methods, the detection method of the present application has the advantages of high measurement accuracy, good real-time performance, no need for reference plane, high measurement repeatability, good vibration resistance, etc. It is suitable for in-situ measurement and has great application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is the optical path diagram of the present invention;

[0048] Figure 2 is a phase distribution diagram of the phase plate in the present invention;

[0049] The horizontal and vertical coordinates represent the coordinate values ​​of the pixels, respectively. The horizontal coordinate represents the x-coordinate of the pixel, and the vertical coordinate represents the y-coordinate of the pixel, both in pixel units. The color bar on the right ranging from 0 to 1 represents the phase distribution of 0 or 1, without units.

[0050] Figure 3 is the diffraction light path diagram collected by the CCD camera in the present invention;

[0051] The horizontal and vertical coordinates represent the coordinate values ​​of the pixels, respectively. The horizontal coordinate represents the x coordinate of the pixel, and the vertical coordinate represents the y coordinate of the pixel, both in pixel. The color bar on the right from 500 to 3500 represents the amplitude, without unit.

[0052] Figure 4 is the surface shape distribution of the component after reconstruction in the present invention;

[0053] The horizontal and vertical coordinates represent the coordinate values ​​of the pixels, respectively. The horizontal coordinate represents the x-coordinate of the pixel, and the vertical coordinate represents the y-coordinate of the pixel, both in pixel units. The color bar on the right side from -0.15 to 0.2 represents the surface distribution, and the unit is wavelength.

[0054] Wherein, the accompanying drawings are marked as follows:

[0055] 101-laser, 102-beam isolator, 103-beam splitter, 104-collimator A, 105-optical machine component to be measured, 106-light screen with holes, 107-collimator B, 108-phase plate, 109-CCD camera, 110-computer system. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0057] Therefore, based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0058] Embodiment 1:

[0059] The present embodiment provides an in-situ detection device for the surface shape of an optical-mechanical component, comprising a laser 101, a beam isolator 102, a beam splitter prism 103, a collimator A 104, an optical-mechanical component to be measured 105, a perforated light screen 106, a collimator B 107, a phase plate 108, a CCD camera 109, and a computer system 110, wherein the CCD camera 109 is connected to the computer system 110.

[0060] The laser 101 and the perforated light screen 106 are both located at the focal position of the collimator A104, and the wavelength of the laser output by the laser 101 is 632.8 nm. The center of the perforated light screen 106 has a small hole with a diameter of 2 mm.

[0061] The collimator A104 and the collimator B107 are placed cofocally, and the focal length ratio of the collimator A104 and the collimator B107 is 8.

[0062] The beam splitting ratio of the beam splitting prism 103 is 1:1.

[0063] The distance between the phase plate 108 and the target surface of the CCD camera 109 is 20 mm.

[0064] The phase plate 108 is a phase-type transmission element, and the design requirements are:

[0065] (a) Substrate size: The substrate of the phase plate 108 is made of fused quartz, and the size of the substrate is φ25.4 mm×1.5 mm;

[0066] (b) Phase modulation area: the effective aperture is 15 mm, transmission type, the phase modulation cells in the phase modulation area are randomly distributed, and the size of the phase modulation cells is 20 μm;

[0067] (c) Optical path difference: The phase plate 108 is fabricated by photolithography, with a duty ratio of 0.5, and an optical path difference of 130 nm between the etched area and the non-etched area;

[0068] (d) Use wavelength: 632.8nm.

[0069] like Figure 1 As shown, the optical path of the device is:

[0070] The laser light generated by the laser 101 passes through the beam isolator 102, the beam splitter prism 103, and the collimator A104 in sequence, and then is incident on the optical machine component to be measured 105, and the laser light is reflected on the optical machine component to be measured 105; the reflected light of the optical machine component to be measured 105 passes through the collimator A104 and then is incident on the beam splitter prism 103, and the returned laser light is reflected on the beam splitter prism 103, and the reflected light of the beam splitter prism 103 passes through the perforated light screen 106, the collimator B107, and the phase plate 108 in sequence, and then is incident on the CCD camera 109; the CCD camera 109 is connected to the computer system 110, and the light spot pattern recorded by the CCD camera 109 will be input into the computer system 110 for in-situ surface shape detection.

[0071] Embodiment 2:

[0072] This embodiment provides a method for detecting the surface shape of an optomechanical component, including an apparatus for detecting the surface shape of an optomechanical component. The apparatus for detecting the surface shape of an optomechanical component adopts the apparatus for detecting the surface shape of an optomechanical component described in Example 1.

[0073] When the optical-mechanical component surface shape in-situ detection device is used to perform surface shape in-situ detection, the specific steps are as follows:

[0074] Step 1, laser 101 emits laser, which passes through beam isolator 102, beam splitter prism 103, collimator A104, optical machine component to be measured 105, collimator A104, beam splitter prism 103, perforated light screen 106, collimator B107, phase plate 108, and CCD camera 109 in sequence.

[0075] The posture of the optical-mechanical component surface shape in-position detection device is adjusted so that the laser reflected by the beam splitter prism 103 passes through the small hole in the center of the perforated light screen 106 and generates a diffraction spot on the CCD camera 109.

[0076] Step 2: Collect and save the diffraction spots corresponding to different image plane coordinates of the CCD camera 109 ,in is the image plane coordinate.

[0077] Step 3: Using the calibrated complex amplitude of the phase plate 108 , diffraction spot Iterate the surface shape of the optical machine component 105 to be measured; the specific iteration steps are:

[0078] Step 1, the laser 101 emits a laser to adjust the posture of the optical-mechanical component surface shape in-situ detection device, and the laser passes through the beam isolator 102, the beam splitter prism 103, the collimator A104, the optical-mechanical component to be measured 105, the collimator A104, the beam splitter prism 103, the perforated light screen 106, the collimator B107, the phase plate 108, and the CCD camera 109 in sequence, and a diffraction spot is generated on the CCD camera 109;

[0079] Step 2: Collect and save the diffraction spots corresponding to different image plane coordinates of the CCD camera 109 ;

[0080] Step 3: Using the complex amplitude of the light field of the phase plate 108 , diffraction spot Iterate the surface shape of the optical machine component 105 to be measured; the specific iteration steps are:

[0081] Step 3-1, giving the optical machine component 105 to be tested an initial randomly guessed light field complex amplitude ;

[0082] Step 3-2, support domain constraint S: refers to the constraint on the optical machine component 105 to be measured, which is used to limit the size and position of the light field complex amplitude distribution area of ​​the optical machine component 105 to be measured:

[0083] ;

[0084] Step 3-3, the complex amplitude of the limited light field transmitted to the phase plate 108, and the incident light field complex amplitude of the phase plate 108 is obtained respectively , complex amplitude of the outgoing light field :

[0085] ;

[0086] ;

[0087] Step 3-4: complex the amplitude of the output light field of the phase plate 108 Transmitted to CCD camera 109, the complex amplitude of the light field of CCD camera 109 is obtained :

[0088] ;

[0089] Step 3-5, using the diffraction spot collected by the CCD camera 109 Complex amplitude of light field To perform a modulus constraint:

[0090] ;

[0091] Step 3-6: The constrained light field complex amplitude The complex amplitude of the updated output light field of the phase plate 108 is obtained. , update the complex amplitude of the incident light field :

[0092] ;

[0093] ;

[0094] Step 3-7 will update the complex amplitude of the incident light field The light field complex amplitude of the optical machine component 105 to be measured is updated to obtain the updated light field complex amplitude of the optical machine component 105 to be measured. :

[0095] ;

[0096] ;

[0097] Step 3-8, repeat steps 3-1 to 3-7 until the loop termination condition is met and the iteration is completed;

[0098] in, represents the image plane coordinates in the CCD camera 109, represents the image plane coordinates of the phase plate 108 and the optical machine component to be measured 105, represents the support domain, represents the diffraction transmission operation, represents the complex conjugate of the complex amplitude of the light field of the phase plate 108, represents the inverse diffraction transmission operation, It represents the complex amplitude of the light field transmitted back to the optical machine component 105 to be measured.

[0099] The loop termination condition is: When it is less than the requirement of the convergence criterion (the requirement of the convergence criterion here is set according to the measurement needs), the iteration loop is jumped out;

[0100] ;

[0101] Where N is the total number of iterations, represents the beam amplitude distribution of the image plane of the CCD camera 109 at the nth iteration, represents the diffraction spot collected by the CCD camera 109. Step 3 When calibrating the phase plate 108, the specific calibration steps are:

[0102] (a) Place a perforated light screen 106 with a diameter of 1 mm on a two-dimensional translation stage to ensure that the plane of the perforated light screen 106 is perpendicular to the optical path;

[0103] (b) Assign initial random guesses to the complex amplitudes of the phase plate 108 and the perforated light screen 106 (including the complex amplitude of the illumination light), respectively. , Indicates; among them, represents the displacement vector of the phase plate plane, Represents the displacement vector corresponding to the scan area;

[0104] (c) The complex amplitude of the phase plate 108 and the complex amplitude of the perforated light screen 106 Multiply them together to get the complex amplitude of the outgoing wave from the object, which is:

[0105] ;

[0106] in, Indicates regions (scanning subapertures), Indicates the number of iterations;

[0107] (d) The complex amplitude of the outgoing wave Transmitted to the recording plane of CCD camera 109, the complex amplitude of the light field is obtained ,Right now:

[0108] ;

[0109] in, represents the angular spectrum diffraction transmission operation, Indicates the transmission distance;

[0110] (e) The square root value of the diffraction spot recorded by the CCD camera 109 replace The modulus of and the phase remain unchanged to form a new complex amplitude value, that is:

[0111] ;

[0112] (f) The complex amplitude Propagate in reverse to the plane of the optical machine component 105 to be measured, and obtain the complex amplitude of the sample output light closer to the true value:

[0113] ;

[0114] in, represents the inverse-angle spectrum diffraction transmission operation, Indicates the transmission distance;

[0115] (g) Update the complex amplitude of the perforated light screen 106 and the complex amplitude of the phase plate 108 , and the complex amplitude of the light emitted by the phase plate 108 is obtained, which is closer to the true value:

[0116] ;

[0117] ;

[0118] in, , They are all constants, generally positive numbers between 0 and 1;

[0119] (h) The perforated light screen 106 moves to the next position, where there is an overlapping area with the last scanned area, and the above steps are repeated until an accurate convergence result is obtained;

[0120] The following formula is used as the iterative convergence criterion, when When the value is less than the convergence criterion, the iteration loop is exited:

[0121] ;

[0122] in, represents the total number of iterations, Indicates the total number of regions. Indicates the nth iteration The complex amplitude of the CCD camera 109 calculated for each area, Indicates The diffraction spot (light intensity distribution) of the area CCD camera 109.

[0123] Test example:

[0124] The optical-mechanical component surface shape in-situ detection device of Example 1 and the optical-mechanical component surface shape in-situ detection method of Example 2 are used to perform surface shape in-situ detection on an optical-mechanical component with a diameter of 400 mm.

[0125] After testing, the phase distribution of the phase plate 108 is obtained as follows: Figure 2 As shown, the diffraction spots collected by the CCD camera 109 are as follows: Figure 3 As shown; after multiple iterations, the surface distribution of the optical machine component to be measured with an aperture of 400mm is obtained as follows Figure 4 shown.

Claims

1. An optical-mechanical component surface shape in-situ detection device, characterized in that: It comprises a laser (101), a beam isolator (102), a beam splitter prism (103), a collimator A (104), an optical machine component to be measured (105), a light screen with holes (106), a collimator B (107), a phase plate (108), a CCD camera (109), and a computer system (110); The laser light generated by the laser (101) passes through the beam isolator (102), the beam splitter prism (103), and the collimator A (104) in sequence, and then enters the optical machine component (105) to be measured and generates reflection. The reflected light of the optical machine component (105) to be measured passes through the collimator A (104) and then enters the beam splitter prism (103) and generates reflection. The reflected light of the beam splitter prism (103) passes through the perforated light screen (106), the collimator B (107), and the phase plate (108) and then enters the CCD camera (109). The CCD camera (109) is connected to the computer system (110), and the light spot pattern recorded by the CCD camera (109) is input into the computer system (110) for in-situ surface shape detection. When the above-mentioned optical-mechanical component surface shape in-situ detection device is used for detection, the specific steps are as follows: Step 1, a laser (101) emits a laser, and the posture of the optical-mechanical component surface shape in-situ detection device is adjusted. The laser passes through a beam isolator (102), a beam splitter prism (103), a collimator A (104), an optical-mechanical component to be measured (105), a collimator A (104), a beam splitter prism (103), a perforated light screen (106), a collimator B (107), a phase plate (108), and a CCD camera (109) in sequence, and generates a diffraction spot on the CCD camera (109); Step 2: Collect and save the diffraction spots corresponding to different image plane coordinates of the CCD camera (109) ; Step 3: Using the complex amplitude of the light field from the phase plate (108) , diffraction spot Iterate the surface shape of the optical machine component (105) to be measured; the specific iterative steps are: Step 3-1, giving the optical machine component (105) to be tested an initial randomly guessed light field complex amplitude ; Step 3-2, support domain constraint S: refers to the constraint on the optical machine component (105) to be measured, and the constraint is used to limit the size and position of the light field complex amplitude distribution area of ​​the optical machine component (105) to be measured: ； Step 3-3, the restricted random guess transmitted to the phase plate (108), and the incident light field complex amplitude of the phase plate (108) is obtained respectively , complex amplitude of the outgoing light field : ； ； Step 3-4, the output light field of the phase plate (108) is complex-amplified Transmitted to the CCD camera (109), the complex amplitude of the light field of the CCD camera (109) is obtained : ； Step 3-5, using the CCD camera (109) to collect the diffraction spot Complex amplitude of light field To perform a modulus constraint: ； Step 3-6: The constrained light field complex amplitude The complex amplitude of the updated output light field of the phase plate (108) is obtained by back-transmitting to the phase plate (108) , update the complex amplitude of the incident light field : ； ； Step 3-7 will update the complex amplitude of the incident light field The light field complex amplitude of the optical machine component to be measured (105) is updated, and the updated light field complex amplitude of the optical machine component to be measured (105) is obtained. : ； ； Step 3-8, repeat steps 3-1 to 3-7 until the loop termination condition is met and the iteration is completed; in, represents the image plane coordinates in the CCD camera (109), represents the image plane coordinates in the phase plate (108) and the optical machine component to be measured (105), represents the support domain, represents the diffraction transmission operation, represents the complex conjugate of the complex amplitude of the light field of the phase plate (108), represents the inverse diffraction transmission operation, Represents the complex amplitude of the light field transmitted back to the optical machine component (105) to be measured.

2. The optical-mechanical component surface shape in-position detection device according to claim 1, characterized in that: The laser (101) and the light screen with holes (106) are both located at the focal position of the collimator A (104).

3. The optical-mechanical component surface shape in-position detection device according to claim 1, characterized in that: The collimator A (104) and the collimator B (107) are placed cofocally, and the focal length ratio of the collimator A (104) and the collimator B (107) is 8.

4. The optical-mechanical component surface shape in-position detection device according to claim 1, characterized in that: The splitting ratio of the beam splitting prism (103) is 1:

1.

5. The optical-mechanical component surface shape in-situ detection device according to claim 1, characterized in that: The wavelength of the laser output by the laser (101) is 632.8 nm, the diameter of the central small hole of the perforated light screen (106) is 2 mm, and the distance between the phase plate (108) and the target surface of the CCD camera (109) is 20 mm.

6. The optical-mechanical component surface shape in-position detection device according to claim 1, characterized in that: The substrate of the phase plate (108) is made of fused quartz, and the size of the substrate is φ25.4 mm×1.5 mm; The effective aperture of the phase modulation region of the phase plate (108) is 15 mm, the phase modulation cells in the phase modulation region are randomly distributed, and the size of the phase modulation cells is 20 μm; The phase plate (108) is manufactured by photolithography, with a duty ratio of 0.5, and an optical path difference of 130 nm between an etched area and a non-etched area.

7. The optical-mechanical component surface shape in-position detection device according to claim 1, characterized in that: In step 3-8, the loop termination condition is: When it is less than the requirement of the convergence criterion, the iteration loop is jumped out; ； Where N is the total number of iterations, represents the beam amplitude distribution on the image plane of the CCD camera (109) at the nth iteration, represents the diffraction spot collected by the CCD camera (109).

Images