A high-precision gauge block automatic measuring device based on dual-wavelength phase-shift interference

Abstract

The application discloses a high-precision gauge block automatic measuring device based on double-wavelength phase-shifting interference and belongs to the technical field of gauge block measuring devices, which comprises two groups of heat preservation boxes, a partition chamber fixedly installed between the two groups of heat preservation boxes, CCD cameras fixedly installed at both ends in the partition chamber and facing the heat preservation boxes through second window surfaces, the second window surfaces being arranged at both ends in the partition chamber, converging mirrors fixedly installed in the heat preservation boxes, mounting tables fixedly installed at one end of the outer surfaces of the two groups of heat preservation boxes, frequency-stabilized lasers fixedly installed on the mounting tables and having laser emitting ends aligned with collimating mirrors in the heat preservation boxes through first window surfaces, the first window surfaces being arranged at one end of the heat preservation boxes, and the collimating mirrors being fixedly installed in the heat preservation boxes. Through the design of the angle rotation adjusting mechanism, the high precision of large-size gauge block measurement is realized by the deep integration of optical principle innovation, mechanical structure optimization, automatic control and environmental isolation technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gauge block measuring devices, in particular to a high-precision gauge block automatic measuring device based on dual-wavelength phase-shifting interference. BACKGROUND

[0002] In modern industrial production and scientific research, length measurement is a key link to ensure product quality and technical precision. Gauge blocks, as important physical benchmarks in the field of length measurement, directly affect the accuracy and reliability of the entire measurement system. From precision mechanical processing to high-end optical instrument manufacturing, from aerospace parts production to semiconductor chip processing, the demand for high-precision measurement of gauge blocks is increasingly urgent.

[0003] Traditional gauge block measurement methods, such as contact measurement, are not only inefficient and susceptible to human factors, but also difficult to meet the measurement requirements of microns or even nanometers in terms of measurement accuracy. SUMMARY

[0004] The present application aims to provide a high-precision gauge block automatic measuring device based on dual-wavelength phase-shifting interference to solve the problems of low efficiency, poor measurement accuracy, and large measurement result deviation caused by human operation in traditional gauge block measurement methods, which cannot meet the high-precision industrial demand and cannot adapt to the modern automated and intelligent production scenarios for rapid and accurate measurement of gauge blocks.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] A high-precision gauge block automatic measuring device based on dual-wavelength phase-shifting interference, comprising: two sets of heat preservation boxes, a partition chamber is fixedly installed between the two sets of heat preservation boxes, a CCD camera is fixedly installed at both ends of the partition chamber and faces the converging mirror in the heat preservation box through a second window, the second window is opened at both ends of the partition chamber, and the converging mirror is fixedly installed in the heat preservation box, an installation table is fixedly installed at one end of the outer surface of each of the two sets of heat preservation boxes, a frequency stabilized laser is fixedly installed on the installation table, and the laser emitting end of the frequency stabilized laser is aligned with a collimating mirror in the heat preservation box through a first window, the first window is opened at one end of the heat preservation box, the collimating mirror is fixedly installed in the heat preservation box, one end of the collimating mirror is aligned with a first reflecting mirror, one end of the first reflecting mirror is aligned with a beam splitter, both ends of the beam splitter are aligned with a PZT phase shifter and a converging mirror, one end of the converging mirror is aligned with the CCD camera, and one end of the beam splitter is aligned with a second reflecting mirror.

[0007] Preferably, the first mirror, the second mirror and the beam splitter are equidistantly rotatably installed on the upper surface of the angle tuning mechanism, the angle tuning mechanism is longitudinally fixedly installed in the incubator, and the PZT phase shifter is fixedly installed in the incubator.

[0008] One end of the second mirror is flush with the transmission port of the storage box, the storage box is fixedly installed in the incubator and communicates with the sliding frame, the transmission port is formed in one end of the storage box, the sliding frame is fixedly installed at one end of the incubator, the sealing plate is slidably installed in the sliding frame, and the sealing plate can seal the storage box by sliding in the sliding frame.

[0009] A flat crystal plate is fixedly installed at one end of the storage box, and a pressing and clamping mechanism is fixedly installed at the other end, the pressing and clamping end of the pressing and clamping mechanism is located at the upper and lower ends of the transmission port to avoid the reflected light path, and when the measured object is placed in the storage box, the measured object can be pushed by the pressing and clamping mechanism to one end of the flat crystal plate.

[0010] Preferably, when the measured object is measured, the frequency stabilized laser emits laser with a stable wavelength, the laser is expanded into parallel light by the collimating mirror first, and then is incident on the first mirror in a parallel state, the first mirror reflects the parallel light into the beam splitter and divides it into two paths.

[0011] Preferably, the two paths of laser light divided by the beam splitter are respectively a reference light path and a measurement light path.

[0012] Reference light path: after the light is reflected by the beam splitter, the light is reflected by the mirror driven by the PZT phase shifter to form a reference light beam;

[0013] Measurement light path: after the light transmits through the beam splitter and is reflected by the second mirror, the light irradiates the surface of the gauge block and the flat crystal plate in the storage box, the reflected light of the gauge block and the flat crystal is converged at the beam splitter to form interference fringes.

[0014] Preferably, the pressing and clamping mechanism comprises a connecting plate, the connecting plate is fixedly installed at one end of the storage box, motors are fixedly installed on one side of the upper and lower ends of the connecting plate, first connecting arms are rotatably installed on the outer surfaces of the upper and lower ends of the motors, an extension plate is fixedly installed on one end of the outer surface of the motor, second connecting arms are rotatably installed on the outer surfaces of the upper and lower ends of the extension plate, a pressing plate is rotatably installed between the other ends of the first connecting arms and the second connecting arms, the pressing plate is rotatably connected with the first connecting arms and the second connecting arms, so that when the motor drives the first connecting arms to twist the pressing plate, the second connecting arms can swing around the hinge point on the extension plate through the pressing plate, and the coordinated movement of the two forces the pressing plate to move in a direction perpendicular to the surface of the gauge block.

[0015] Preferably, the angle rotation mechanism comprises a mounting plate fixedly installed longitudinally in the heat preservation box, and the upper surface of the mounting plate is provided for equidistant rotation installation of the first mirror, the second mirror and the beam splitter;

[0016] One end of the upper surface of the mounting plate is rotationally installed with a first rotating column, the outer surface of the first rotating column is rotationally installed with a second rotating column, the outer surface of the second rotating column is rotationally installed with a third rotating column, and the upper ends of the first rotating column, the second rotating column and the third rotating column are rotationally penetrated out of the heat preservation box.

[0017] Preferably, the outer surfaces of the first rotating column, the second rotating column and the third rotating column are fixedly installed with first transmission discs, and the outer surfaces of the rotating columns of the first mirror, the second mirror and the beam splitter are fixedly installed with second transmission discs;

[0018] The first rotating column and the second mirror are transmissionally connected through the synchronous belts sleeved on the outer surfaces of the first transmission discs and the second transmission discs;

[0019] The second rotating column and the beam splitter are transmissionally connected through the synchronous belts sleeved on the outer surfaces of the first transmission discs and the second transmission discs;

[0020] The third rotating column and the first mirror are transmissionally connected through the synchronous belts sleeved on the outer surfaces of the first transmission discs and the second transmission discs.

[0021] Preferably, the outer surfaces of the first rotating column, the second rotating column and the third rotating column rotationally penetrated out of the heat preservation box are fixedly installed with hand wheels, the outer surfaces of the hand wheels are equidistantly fixedly installed with protruding teeth, the protruding teeth on the outer surfaces of the three groups of hand wheels can be embedded in one corner of the V-shaped plates, the three groups of V-shaped plates are equidistantly rotationally installed in a U-shaped frame, and the U-shaped frame is fixedly installed on one end of the upper surface of the heat preservation box.

[0022] Preferably, one end of the U-shaped frame is provided with a sliding slot, a tapered block is slidingly installed in the sliding slot, one end of the tapered block is fixedly connected with one end of a spring, and the other end of the spring is fixedly connected with the other end of the sliding slot.

[0023] The spring applies a spring pushing force to the tapered block, so that the tapered block abuts against one end of the three groups of V-shaped plates, and one corner of the three groups of V-shaped plates is rotationally clamped into the spacing of the protruding teeth of the hand wheels.

[0024] Preferably, the hand wheels and the V-shaped plates form a limiting structure similar to a ratchet wheel through elastic clamping cooperation, so as to prevent the hand wheels from being accidentally deflected.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] 1. By the design of the incubator, the storage box, the flat crystal plate, the CCD camera, the converging mirror, the frequency stabilized laser, the collimating mirror, the first mirror, the beam splitter, the second mirror, the PZT phase shifter, the angle adjustment mechanism and the clamping mechanism, when measuring the gauge block, the gauge block can be placed in the storage box installed in the incubator, then the clamping mechanism can be started to press the gauge block to touch one end of the flat crystal plate and align with the transmission port, then the frequency stabilized laser can be started to emit stable wavelength laser, the laser is expanded into parallel light by the collimating mirror, and the parallel light is incident to the first mirror, the first mirror reflects the parallel light into the beam splitter to divide the laser into two paths, one path is the reference light path and the other path is the measurement light path;

[0027] The light of the reference light path is reflected by the mirror driven by the PZT phase shifter to form a reference beam, and the light of the measurement light path is transmitted through the beam splitter and reflected by the second mirror to irradiate the gauge block and the flat crystal plate in the storage box, the reflected light of the gauge block and the flat crystal plate converges with the reference beam at the beam splitter to form interference fringes, and the interference fringes are collected by the CCD camera after converging by the converging mirror;

[0028] In this process, the angle adjustment mechanism can accurately adjust the relative angles of the first mirror, the second mirror and the beam splitter to ensure that the light path is strictly aligned, the PZT phase shifter drives the reference mirror to periodically change the optical path of the reference light path by nanoscale displacement, and the five-step phase shifting method is realized (each phase shift is π / 2), and the CCD camera collects five interference images with different phases in sequence;

[0029] The interference images are processed by special measurement software, the phase distribution is calculated by the five-step phase shifting algorithm, the phase wrapping is eliminated by the phase unwrapping technology, the phase difference between the center point of the gauge block and the corresponding area of the flat crystal is obtained, and then the decimal level of the interference fringes is calculated, and the integer wavelength number is solved by the double-wavelength decimal coincidence method, and finally the length of the gauge block is obtained, the device realizes high precision, high efficiency and high reliability in large size gauge block measurement through the deep integration of optical principle innovation, mechanical structure optimization, automatic control and environmental isolation technology, breaks through the bottleneck of traditional methods in range, precision and automation, and is suitable for scenes with strict demand for length measurement such as metrological verification, precision manufacturing and scientific research institutions.

[0030] 2. Through the design of the motor, first connecting arm, second connecting arm, top pressure plate, and extension plate, the motor can be started after the gauge block is filled into the storage box. The motor then drives the first connecting arm to rotate around the motor axis via the output shaft. Simultaneously, the second connecting arm, through its rotating connection with the top pressure plate, causes the second connecting arm to swing around the hinge point of its extension plate. Since both the first and second connecting arms are rotatingly connected to the top pressure plate, their coordinated motion forces the top pressure plate to translate in a direction perpendicular to the surface of the gauge block. During this process, the circular motion component of the first connecting arm is... The swing component of the second connecting arm synthesizes a linear motion trajectory through the hinge point of the top pressure plate, and the synchronous drive of the upper and lower motors makes the top pressure plate subject to symmetrical driving force and maintain a horizontal posture. When the motor rotates in the forward direction, the top pressure plate moves towards the flat crystal plate to press the gauge block. When it rotates in the reverse direction, it retracts and releases the gauge block. This structure converts the rotational motion of the motor into the linear motion of the top pressure plate through multi-link linkage. The symmetrical layout ensures uniform clamping force, avoids uneven force on the gauge block, deformation or displacement, and ensures the fitting accuracy between the gauge block and the flat crystal, providing a stable physical basis for interferometric measurement.

[0031] 3. Through the design of the U-shaped frame, handwheel, cone block, spring, first transmission disc, second transmission disc, first rotating column, second rotating column, and third rotating column, when it is necessary to adjust the angle of the optical element, the handwheel can be manually rotated to drive the coaxial first rotating column, second rotating column, or third rotating column to rotate. The first transmission disc on the outer surface of the rotating column drives the corresponding second transmission disc to rotate through the synchronous belt, thereby driving the first reflector, second reflector, or beam splitter to rotate around their respective rotating column axes, thus achieving fine adjustment of the angle. During the adjustment process, the spring will always apply a spring force to the three sets of V-shaped plates through the cone block, so that one corner of the V-shaped plate is engaged in the tooth spacing on the outer surface of the handwheel, forming a one-way limiting structure similar to a ratchet. The engagement of the teeth with the V-shaped plate locks the position of the handwheel, preventing the handwheel from rotating due to vibration or accidental contact, thereby ensuring that the relative angle of the first reflector, second reflector, and beam splitter remains stable and ensuring the optical path alignment accuracy of the optical system. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0033] Figure 2 This is a schematic diagram of the structure of the partition plate of the present invention;

[0034] Figure 3 This is a schematic diagram of the structure of the storage box and the transmission port of the present invention;

[0035] Figure 4 This is a schematic diagram of the collimating mirror, the first reflecting mirror, the beam splitter, and the second reflecting mirror of the present invention.

[0036] Figure 5 This is a top view of the overall structure of the present invention;

[0037] Figure 6 The schematic diagram of the massive block interferometer measurement of the present application;

[0038] Figure 7 The schematic diagram of the structure of the connecting plate and the motor of the present application;

[0039] Figure 8 The schematic diagram of the structure of the pressing mechanism of the present application;

[0040] Figure 9 The schematic diagram of the structure of the connecting plate and the hand wheel of the present application;

[0041] Figure 10 The schematic diagram of the structure of the V-shaped plate being pushed by the tapered block of the present application;

[0042] Figure 11 The schematic diagram of the structure of the first rotating column, the second rotating column and the third rotating column of the present application.

[0043] In the figure: 1, heat preservation box; 101, sliding frame; 102, sealing plate; 103, storage box; 104, transmission port; 105, flat crystal plate; 106, separate chamber; 107, CCD camera; 108, converging mirror; 109, frequency stabilization laser; 110, collimating mirror; 111, first reflecting mirror; 112, beam splitter; 113, second reflecting mirror; 114, PZT phase shifter; 2, angle rotation adjusting mechanism; 201, mounting plate; 202, V-shaped frame; 203, V-shaped plate; 204, hand wheel; 205, tapered block; 206, spring; 207, second transmission disc; 208, first rotating column; 209, second rotating column; 210, third rotating column; 211, first transmission disc; 212, synchronous belt; 213, sliding slot; 3, pressing mechanism; 301, connecting plate; 302, motor; 303, first connecting arm; 304, second connecting arm; 305, pressing plate; 306, extension plate; 4, first transmission window; 401, second transmission window; 402, mounting table. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work belong to the scope of protection of the present application.

[0045] Please refer to Figures 1-11 The present embodiment provides the following technical solutions:

[0046] As Figures 1-6As shown, a high-precision block automatic measuring device based on dual-wavelength phase shift interference includes: two sets of incubators 1, two sets of incubators 1 are fixedly installed between the partition chambers 106, the CCD camera 107 is fixedly installed at both ends in the partition chamber 106 and faces the incubator 1 through the second window 401, the second window 401 is opened at both ends in the partition chamber 106, and the condenser lens 108 is fixedly installed in the incubator 1, the mounting table 402 is fixedly installed at one end of the outer surface of the two sets of incubators 1, the frequency stabilized laser 109 is fixedly installed on the mounting table 402, and the laser emitting end of the frequency stabilized laser 109 is flush with the collimating lens 110 in the incubator 1 through the first window 4, the first window 4 is opened at one end of the incubator 1, the collimating lens 110 is fixedly installed in the incubator 1, one end of the collimating lens 110 is flush with the first mirror 111, one end of the first mirror 111 is flush with the beam splitter 112, both ends of the beam splitter 112 are flush with the PZT phase shifter 114 and the condenser lens 108 respectively, one end of the condenser lens 108 is flush with the CCD camera 107, one end of the beam splitter 112 is flush with the second mirror 113;

[0047] Wherein, the first mirror 111, the second mirror 113 and the beam splitter 112 are rotatably installed at equal intervals on the upper surface of the angle adjustment mechanism 2, the angle adjustment mechanism 2 is fixedly installed longitudinally in the incubator 1, and the PZT phase shifter 114 is fixedly installed in the incubator 1;

[0048] Wherein, one end of the second mirror 113 is flush with the transmission port 104 of the storage box 103, the storage box 103 is fixedly installed in the incubator 1 and is in communication with the sliding frame 101, and the transmission port 104 is opened at one end of the storage box 103, the sliding frame 101 is fixedly installed at one end of the incubator 1, the sealing plate 102 is slidingly installed in the sliding frame 101, and the sealing plate 102 can cover the storage box 103 by sliding in the sliding frame 101;

[0049] Wherein, the flat crystal plate 105 is fixedly installed at one end in the storage box 103, and the clamping mechanism 3 is fixedly installed at the other end in the storage box 103, the clamping end of the clamping mechanism 3 is located at the upper and lower ends of the transmission port 104 so as to avoid the reflection light path, so that the measured part can be pushed by the clamping mechanism 3 to one end of the flat crystal plate 105 when placed in the storage box 103.

[0050] The frequency stabilized laser 109 can be started to emit laser with stable wavelength for measuring and detecting the measured part, the laser is first expanded into parallel light by the collimating lens 110 to ensure that the light is incident on the first mirror 111 in a parallel state, and the first mirror 111 can reflect the parallel light into the beam splitter 112 to divide the laser into two paths.

[0051] The laser divided by the beam splitter 112 into two paths is respectively a reference light path and a measurement light path;

[0052] The reference light path: the light is reflected by the PZT phase shifter 114 driven mirror after being reflected by the beam splitter 112, to form a reference beam;

[0053] The measurement light path: the light is reflected by the second mirror 113 after being transmitted through the beam splitter 112, and then irradiates the gauge block and the surface of the flat crystal plate 105 in the storage box 103. The reflected light of the gauge block and the flat crystal converges with the reference beam at the beam splitter 112 to form interference fringes.

[0054] Through the design of the incubator 1, the storage box 103, the flat crystal plate 105, the CCD camera 107, the converging mirror 108, the frequency stabilized laser 109, the collimating mirror 110, the first mirror 111, the beam splitter 112, the second mirror 113, the PZT phase shifter 114, the angle adjustment mechanism 2 and the clamping mechanism 3, when measuring the gauge block, the gauge block can be placed in the storage box 103 installed in the incubator 1. Then the clamping mechanism 3 can be started to press the gauge block to touch one end of the flat crystal plate 105 and be flush with the transmission port 104. Then the frequency stabilized laser 109 can be started to emit a stable wavelength laser. The laser is expanded into parallel light by the collimating mirror 110, and then is incident to the first mirror 111 in a parallel state. The first mirror 111 reflects the parallel light into the beam splitter 112 to divide the laser into two paths, one of which is the reference light path and the other of which is the measurement light path.

[0055] The light of the reference light path is reflected by the PZT phase shifter 114 driven mirror after being reflected by the beam splitter 112, to form a reference beam. The light of the measurement light path is reflected by the second mirror 113 after being transmitted through the beam splitter 112, and then irradiates the gauge block and the surface of the flat crystal plate 105 in the storage box 103. The reflected light of the gauge block and the flat crystal converges with the reference beam at the beam splitter 112 to form interference fringes. The interference fringes are converged by the converging mirror 108 and then are collected by the CCD camera 107.

[0056] During this process, the angle adjustment mechanism 2 can accurately adjust the relative angles of the first mirror 111, the second mirror 113 and the beam splitter 112 to ensure that the light path is strictly aligned. The PZT phase shifter 114 periodically changes the optical path of the reference light path by nanoscale displacement driving the reference mirror, to realize the five-step phase shifting method (each time the phase is shifted by π / 2). The CCD camera 107 sequentially collects five interference images with different phases.

[0057] The dedicated measurement software is used for processing the interference image, the phase distribution is calculated by using a five-step phase-shifting algorithm, the phase wrapping is eliminated by combining a phase unwrapping technology, the phase difference between the center point of the gauge block and the corresponding area of the flat crystal is obtained, and then the decimal order of the interference fringes is calculated, and the integer wavelength number is solved by using the double-wavelength decimal coincidence method to solve the interference decimal of the two wavelengths, and finally the length of the gauge block is obtained. Let the device realize high precision, high efficiency and high reliability in large-size gauge block measurement through the deep integration of optical principle innovation, mechanical structure optimization, automatic control and environmental isolation technology, break through the bottleneck of traditional methods in range, precision and automation, and be suitable for scenes with strict demand for length measurement such as metrological verification, precision manufacturing, scientific research institutions and the like.

[0058] The system architecture and function modules of the dedicated measurement software are as follows:

[0059] 1. Hardware control module

[0060] PZT phase shifter control: drive the PZT phase shifter 114 to execute the five-step phase-shifting method, and the optical path difference corresponding to each phase shift is λ / 4 (i.e. phase difference π / 2). Send instructions through a serial port or a PCI interface to realize nanometer-level displacement precision.

[0061] Example control flow: initialize the PZT phase shifter to zero position; shift phase by 0, π / 2, π, 3π / 2 and 2π in turn, and trigger the CCD camera 107 to collect interference images after each phase shift, and a total of 5 different phase images are obtained.

[0062] CCD camera synchronous acquisition: control the CCD camera through a GigE or USB interface, set exposure time, gain and other parameters to ensure clear collection of interference fringes.

[0063] 2. Image processing and algorithm module

[0064] Interference image preprocessing:

[0065] Noise removal: use median filtering or Gaussian filtering to eliminate random noise;

[0066] Background correction: acquire a background image without interference light, and deduct the effects of dark current and light source non-uniformity;

[0067] ROI extraction: automatically identify the reflection area of the gauge block and the flat crystal plate 105, and intercept the region of interest (ROI) to reduce the calculation amount.

[0068] Phase calculation:

[0069] Five-step phase-shifting algorithm:

[0070] The wrapped phase is calculated by using the following formula on the 5-phase sequence images I1-I5:

[0071]

[0072] where I1-I5 correspond to the light intensity values when the phase shift is 0, π / 2, π, 3π / 2.

[0073] Phase unwrapping:

[0074] The phase unwrapping (jump caused by the phase value being limited in [-π, π]) is eliminated by using the Branch Cut Method or the Least Squares Method, to obtain the continuous phase distribution Φ(x, y).

[0075] Double-wavelength fractional coincidence method:

[0076] Let the two sets of laser wavelengths be λ1, λ 2) , and the corresponding unwrapped phase differences be △Φ1, △Φ2. The height h of the gauge block satisfies:

[0077]

[0078] where λ m is the wavelength, N m is the integer order, and △Φ m is the fractional phase difference.

[0079] By solving the simultaneous equations to eliminate N m , the integer order corresponding to the synthesized wavelength λ 合成 = λ1λ2|λ1-λ2|) is obtained, and finally the high-precision length is obtained:

[0080]

[0081] 3. Data processing and result output module

[0082] Gauge block length calculation:

[0083] Take the phase difference △Φ center of the center point of the gauge block, and combine the reference surface of the flat plate to calculate the height of the gauge block:

[0084]

[0085] Error analysis:

[0086] Automatically calculate the measurement uncertainty, considering factors such as PZT phase shift error, environmental temperature and humidity fluctuations (suppressed by the incubator (1)), CCD noise, and output the expanded uncertainty U.

[0087] Result display:

[0088] Graphically display the interference fringes and the phase distribution cloud map.

[0089] Tabularly output the gauge block length, uncertainty, measurement time, and other parameters.

[0090] Support PDF / Excel report export and historical data query.

[0091] System calibration module

[0092] Wavelength calibration:

[0093] Input the actual wavelength value of the frequency-stabilized laser (e.g., 633 nm, 543 nm), and the software automatically matches the dual-wavelength algorithm parameters.

[0094] Optical path calibration:

[0095] After manually adjusting the angle of the optical element through the angle adjustment mechanism 2, the software collects calibration images, calculates the optical path tilt error, and generates compensation coefficients for subsequent measurement correction.

[0096] Software operation flow

[0097] 1. Parameter setting:

[0098] Select measurement mode (single wavelength / dual wavelength), laser wavelength, and phase shift times (default five steps);

[0099] Set the nominal length range of the gauge block for integer order initial value estimation.

[0100] 2. Automatic measurement:

[0101] Start the clamping mechanism 3 to clamp the gauge block, trigger the PZT phase shifter to shift the phase by the preset step, and simultaneously collect interference images;

[0102] The software automatically completes image processing, phase calculation, and length calculation, without manual intervention throughout the process.

[0103] 3. Result verification:

[0104] Compare the measured value with the nominal value to generate a deviation curve;

[0105] Support repeated measurement and averaging to improve the reliability of the results.

[0106] Technical implementation points

[0107] 1. Development platform:

[0108] Developed using C++ / Python, combined with OpenCV image processing library and Eigen matrix operation library;

[0109] The interface layer uses Qt or PyQt to realize visual interaction.

[0110] 2. Real-time optimization:

[0111] Use multi-threading technology to synchronize image acquisition and processing;

[0112] GPU acceleration (such as CUDA) can be used to accelerate time-consuming algorithms such as phase unwrapping.

[0113] 3. Compatibility:

[0114] Supports Windows / Linux systems and is compatible with mainstream CCD cameras and PZT controller drivers.

[0115] IV. Collaboration with Hardware Systems

[0116] 1. Communication Protocol:

[0117] Define a unified hardware communication protocol, such as controlling the start and stop of motor 302 via Modbus RTU and acquiring CCD image data via TCP / IP protocol.

[0118] 2. Timing synchronization:

[0119] The software generates a phase-shift trigger signal (such as a TTL pulse) to synchronously control the PZT phase shifter's operation and the CCD camera's exposure, ensuring that the phase and image are strictly correlated.

[0120] Dual-wavelength phase-shifting interference principle: The dual-wavelength data fusion and fractional repetition method are realized through software, breaking through the single-wavelength range limitation;

[0121] Automation control: integrates PZT phase shifter and CCD camera control, matching the mechanical actions of clamping mechanism 3 and angle adjustment mechanism 2;

[0122] High-precision algorithm: The five-step phase shifting algorithm and phase unwrapping technology ensure nanometer-level phase measurement accuracy and support high-precision calculation of block length.

[0123] The above approach enables high-precision automatic measurement of large-size blocks through the collaboration of dedicated measurement software and hardware systems.

[0124] like Figures 7-8 As shown, the clamping mechanism 3 has a connecting plate 301, which is fixedly installed at one end inside the storage box 103. Motors 302 are fixedly installed on both the upper and lower ends of the connecting plate 301. A first connecting arm 303 is rotatably installed on the upper and lower ends of the outer surface of the motor 302. An extension plate 306 is fixedly installed on one end of the outer surface of the motor 302. A second connecting arm 304 is rotatably installed on the upper and lower ends of the outer surface of the extension plate 306. A top pressure plate 305 is rotatably installed between the other ends of the first connecting arm 303 and the second connecting arm 304.

[0125] The top pressing plate 305 is connected with the first connecting arm 303 and the second connecting arm 304 through rotation, so that when the motor 302 drives the first connecting arm 303 to twist the top pressing plate 305, the second connecting arm 304 is driven by the top pressing plate 305 to swing around the hinge point on the extension plate 306, and the coordinated movement of the two forces the top pressing plate 305 to move in a direction perpendicular to the surface of the gauge block.

[0126] Through the design of the motor 302, the first connecting arm 303, the second connecting arm 304, the top pressing plate 305 and the extension plate 306, after the gauge block is filled in the storage box 103, the motor 302 can be started, and the motor 302 drives the first connecting arm 303 to move in a circular motion around the axis of the motor 302, and the second connecting arm 304 is driven by the top pressing plate 305 to swing around the hinge point on the extension plate 306. Since the first connecting arm 303 and the second connecting arm 304 are both connected with the top pressing plate 305 through rotation, the coordinated movement of the two forces the top pressing plate 305 to move in a direction perpendicular to the surface of the gauge block. In this process, the circular motion component of the first connecting arm 303 and the swing component of the second connecting arm 304 are combined into a straight line motion track through the hinge point of the top pressing plate 305, and the synchronous driving of the two motors 302 makes the top pressing plate 305 maintain a horizontal posture. When the motor 302 rotates forward, the top pressing plate 305 moves towards the flat plate 105 to press the gauge block, and when the motor 302 rotates reversely, the top pressing plate 305 retreats to release the gauge block. This structure converts the rotary motion of the motor 302 into the linear motion of the top pressing plate 305 through multi-link linkage, uses the symmetrical layout to ensure uniform clamping force, avoids uneven deformation or displacement of the gauge block, ensures the adhesion precision of the gauge block and the flat crystal, and provides a stable physical basis for interference measurement.

[0127] As shown in Figures 9-11 The angle rotation mechanism 2 includes a mounting plate 201, which is fixedly installed in the heat preservation box 1 in a longitudinal direction. The upper surface of the mounting plate 201 is provided with first, second and third reflecting mirrors 111, 113 and a light splitting mirror 112, which are installed in equal distances and rotate on the upper surface of the mounting plate 201. The upper surface of the mounting plate 201 is provided with a first rotating column 208, which is rotatably installed at one end of the upper surface of the mounting plate 201. The outer surface of the first rotating column 208 is rotatably installed with a second rotating column 209. The outer surface of the second rotating column 209 is rotatably installed with a third rotating column 210. The upper ends of the first, second and third rotating columns 208, 209 and 210 are rotatably installed out of the heat preservation box 1.

[0128] The outer surfaces of the first, second and third rotating columns 208, 209 and 210 are fixedly installed with first transmission discs 211. The outer surfaces of the rotating columns of the first, second and third reflecting mirrors 111, 113 and the light splitting mirror 112 are fixedly installed with second transmission discs 207.

[0129] The first rotating column 208 is in transmission connection with the second reflecting mirror 113 through the synchronous belt 212 sleeved on the outer surfaces of the first transmission disc 211 and the second transmission disc 207.

[0130] The second rotating column 209 is in transmission connection with the light splitting mirror 112 through the synchronous belt 212 sleeved on the outer surfaces of the first transmission disc 211 and the second transmission disc 207.

[0131] The third rotating column 210 is in transmission connection with the first reflecting mirror 111 through the synchronous belt 212 sleeved on the outer surfaces of the first transmission disc 211 and the second transmission disc 207.

[0132] The outer surfaces of the first rotating column 208, the second rotating column 209 and the third rotating column 210 are fixedly provided with hand wheels 204, the outer surfaces of the hand wheels 204 are fixedly provided with convex teeth at equal intervals, the convex teeth of the three groups of hand wheels 204 can be buckled into one corner of the V-shaped plates 203, the three groups of V-shaped plates 203 are rotatably arranged in the ovoid frame 202 at equal intervals, and the ovoid frame 202 is fixedly arranged on one end of the upper surface of the heat preservation box 1.

[0133] The ovoid frame 202 is provided with a sliding slot 213 at one end, the sliding slot 213 is slidably provided with a tapered block 205, one end of the tapered block 205 is fixedly connected with one end of a spring 206, the other end of the spring 206 is fixedly connected with the other end of the sliding slot 213, so that the spring 206 can apply a spring pushing force to the tapered block 205, and the tapered block 205 can be pushed by the spring pushing force to abut against one end of the three groups of V-shaped plates 203, so that one corner of the three groups of V-shaped plates 203 can be rotated and buckled into the convex teeth of the hand wheels 204.

[0134] The hand wheels 204 and the V-shaped plates 203 are elastically buckled and matched, a limiting structure similar to a ratchet wheel is formed, and the hand wheels 204 can be effectively prevented from being accidentally deflected.

[0135] When the angle of the optical element needs to be adjusted, the hand wheel 204 is manually rotated to drive the coaxial first rotating column 208, second rotating column 209 or third rotating column 210 to rotate, the first transmission disc 211 on the outer surface of the rotating column drives the corresponding second transmission disc 207 to rotate through the synchronous belt 212, thereby driving the first mirror 111, second mirror 113 or beam splitter 112 to rotate around the respective rotating column axis, so as to realize the fine adjustment of the angle, and in the process of adjustment, the spring 206 always applies a spring pushing force to the three groups of V-shaped plates 203 through the taper block 205, so that one corner of the V-shaped plate 203 is clamped into the tooth spacing on the outer surface of the hand wheel 204, forming a one-way limiting structure similar to a ratchet wheel, and the position of the hand wheel 204 is locked by the meshing of the teeth and the V-shaped plate 203, preventing the rotation of the hand wheel 204 due to vibration or accidental touch, thereby ensuring that the relative angles of the first mirror 111, second mirror 113 and beam splitter 112 remain stable, and the optical path alignment accuracy of the optical system is ensured.

[0136] According to the above technical scheme, the working steps of the present scheme are summarized and combed: when measuring the gauge block, the gauge block can be placed in the storage box 103 installed in the heat preservation box 1, and then the motor 302 can be started, and the motor 302 can drive the first connecting arm 303 to make circular motion around the axis of the motor 302 through the output shaft, and the second connecting arm 304 is driven to swing around the hinge point of the extension plate 306 by the rotation connection with the top pressing plate 305, since the first connecting arm 303 and the second connecting arm 304 are rotationally connected with the top pressing plate 305, the coordinated movement of the two forces the top pressing plate 305 to translate in a direction perpendicular to the surface of the gauge block, so as to press the gauge block against one end of the flat crystal plate 105 and flush with the transmission port 104, and then the frequency stabilized laser 109 can be started to emit laser with a stable wavelength, the laser is expanded into parallel light by the collimating mirror 110, and the parallel light is incident into the first mirror 111, the first mirror 111 reflects the parallel light into the beam splitter 112 to divide the laser into two paths, one path is a reference light path, and the other path is a measurement light path;

[0137] The light of the reference light path is reflected by the PZT phase shifter 114 driven mirror after being reflected by the beam splitter 112 to form a reference light beam, and the light of the measurement light path is reflected by the second mirror 113 after transmitting through the beam splitter 112, and then irradiates the surface of the gauge block and the flat crystal plate 105 in the storage box 103, the reflected light of the gauge block and the flat crystal converges with the reference light beam at the beam splitter 112 to form interference fringes, and the interference fringes are collected by the CCD camera 107 after being converged by the converging mirror 108;

[0138] In the process, the hand wheel 204 can be manually rotated to rotate the coaxial first rotating column 208, second rotating column 209 or third rotating column 210, the first transmission disc 211 on the outer surface of the rotating column drives the corresponding second transmission disc 207 to rotate through the synchronous belt 212, so as to drive the first mirror 111, the second mirror 113 or the beam splitter 112 to rotate around the respective rotating column axis, so as to realize the fine adjustment of the angle, and in the process of adjustment, the spring 206 always applies a spring pushing force to the three groups of V-shaped plates 203 through the taper block 205, so that one corner of the V-shaped plate 203 is clamped into the tooth spacing on the outer surface of the hand wheel 204, forming a one-way limiting structure similar to a ratchet wheel, and the engagement of the tooth and the V-shaped plate 203 locks the position of the hand wheel 204, preventing the rotation of the hand wheel 204 due to vibration or accidental touch, thereby ensuring that the relative angles of the first mirror 111, the second mirror 113 and the beam splitter 112 remain stable, ensuring that the optical path is strictly aligned, the PZT phase shifter 114 periodically changes the optical path of the reference light path through nanoscale displacement driving of the reference mirror, realizes the five-step phase shifting method (each time the phase is shifted by π / 2), and the CCD camera 107 sequentially collects five different phase interference images;

[0139] The interference images are processed by special measurement software, the phase distribution is calculated by using the five-step phase shifting algorithm, the phase wrapping is eliminated by combining the phase unwrapping technology, the phase difference between the center point of the gauge block and the corresponding area of the flat crystal is obtained, and then the decimal order of the interference fringes is calculated, and then the integer wavelength number is solved by the double-wavelength decimal coincidence method, and finally the length of the gauge block is obtained.

[0140] In summary: the device realizes high precision, high efficiency and high reliability of large-size gauge block measurement through the deep integration of optical principle innovation, mechanical structure optimization, automatic control and environmental isolation technology, breaks through the bottleneck of traditional methods in range, precision and automation, and is suitable for scenes with strict demand for length measurement such as metrological verification and precision manufacturing.

[0141] The parts not involved in the present application are the same as or can be realized by the prior art. Although embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to the embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A high-precision gauge block automatic measuring device based on two-wavelength phase-shifting interference, characterized in that, The utility model relates to a kind of temperature-maintaining boxes for measuring the reflectivity of optical element, including: Two groups of temperature-maintaining boxes (1), two groups of temperature-maintaining boxes (1) are fixedly installed with compartment (106) between, compartment (106) is fixedly installed with CCD camera (107) in both ends, and it is through second window (401) and faces with temperature-maintaining box (1) in the flush of converging mirror (108), second window (401) is opened in both ends of compartment (106), and converging mirror (108) is fixedly installed in temperature-maintaining box (1), the outer surface of two groups of temperature-maintaining boxes (1) one end is fixedly installed with mounting table (402), mounting table (402) is fixedly installed with frequency stabilizing laser (109), and let the laser emission end of frequency stabilizing laser (109) through first window (4) and collimating mirror (110) in temperature-maintaining box (1) flush, first window (4) is opened in one end of temperature-maintaining box (1), collimating mirror (110) is fixedly installed in temperature-maintaining box (1), one end of collimating mirror (110) is flush with first reflector (111), the longitudinal one end of first reflector (111) is flush with beamsplitter (112), the transverse both ends of beamsplitter (112) are flush with PZT phase shifter (114) and converging mirror (108) respectively, one end of converging mirror (108) is flush with CCD camera (107), the longitudinal one end of beamsplitter (112) is flush with second reflector (113); First reflector (111), second reflector (113) and beamsplitter (112) are equidistantly rotatably installed on the upper surface of angle rotation mechanism (2), angle rotation mechanism (2) is fixedly installed longitudinally in temperature-maintaining box (1), PZT phase shifter (114) is fixedly installed in temperature-maintaining box (1);One end of second reflector (113) is flush with the transmission port (104) of object box (103), object box (103) is fixedly installed in temperature-maintaining box (1) and is communicated with sliding frame (101), transmission port (104) is opened in one end of object box (103), sliding frame (101) is fixedly installed in one end of temperature-maintaining box (1), sealing plate (102) is slidably installed in sliding frame (101), sealing plate (102) can be covered object box (103) by sliding in sliding frame (101);One end of object box (103) is fixedly installed with flat crystal plate (105), the other end is fixedly installed with pressure clamping mechanism (3), the pressure clamping end of pressure clamping mechanism (3) is located in the upper and lower ends of transmission port (104) to avoid reflecting light path, so that the measured piece can be pushed to one end of flat crystal plate (105) by pressure clamping mechanism (3) when being placed in object box (103). The clamping mechanism (3) comprises a connecting plate (301) fixedly installed at one end in the storage box (103), a motor (302) fixedly installed on one side of the upper and lower ends of the connecting plate (301), a first connecting arm (303) rotatably installed on the upper and lower ends of the outer surface of the motor (302), an extension plate (306) fixedly installed at one end of the outer surface of the motor (302), a second connecting arm (304) rotatably installed on the upper and lower ends of the outer surface of the extension plate (306), a top pressing plate (305) rotatably installed between the other ends of the first connecting arm (303) and the second connecting arm (304), and the top pressing plate (305) is rotatably connected with the first connecting arm (303) and the second connecting arm (304), so that when the motor (302) drives the first connecting arm (303) to twist the top pressing plate (305), the second connecting arm (304) is driven by the top pressing plate (305) to swing around the hinge point on the extension plate (306), and the coordinated movement of the two forces the top pressing plate (305) to translate in a direction perpendicular to the surface of the gauge block.

2. The high-precision gauge block automatic measuring device based on dual-wavelength phase-shifting interference according to claim 1, characterized in that: When the measuring element is measured, the frequency stabilized laser (109) is started to emit laser with a stable wavelength, the laser is expanded into parallel light by the collimating mirror (110) first, and then is incident to the first mirror (111) in a parallel state.

3. The high precision gauge block automatic measuring device based on dual-wavelength phase-shifting interferometry according to claim 2, characterized in that: The two laser beams split by the beam splitter (112) are respectively a reference light path and a measurement light path. The reference light path: the light is reflected by the mirror driven by the PZT phase shifter (114) after being reflected by the beam splitter (112), forming a reference beam; The measurement light path: the light is reflected by the second mirror (113) after transmitting through the beam splitter (112), and then irradiates the surface of the gauge block and the flat crystal plate (105) in the storage box (103), the reflected light of the gauge block and the flat crystal converges with the reference beam at the beam splitter (112), forming interference fringes.

4. The high precision gauge block automatic measuring device based on dual-wavelength phase-shifting interferometry according to claim 3, characterized in that: The angle tuning mechanism (2) comprises a mounting plate (201) fixedly installed longitudinally in the heat preservation box (1), and the first mirror (111), the second mirror (113) and the beam splitter (112) are rotatably installed on the upper surface of the mounting plate (201) at equal distances; A first rotating column (208) is rotatably installed at one end of the upper surface of the mounting plate (201), a second rotating column (209) is rotatably installed on the outer surface of the first rotating column (208), a third rotating column (210) is rotatably installed on the outer surface of the second rotating column (209), and the upper ends of the first rotating column (208), the second rotating column (209) and the third rotating column (210) are rotatably penetrated out of the heat preservation box (1).

5. The high precision gauge block automatic measuring device based on dual-wavelength phase-shifting interferometry according to claim 4, characterized in that: First transmission discs (211) are fixedly installed on the outer surfaces of the first rotating column (208), the second rotating column (209) and the third rotating column (210), and second transmission discs (207) are fixedly installed on the outer surfaces of the rotating columns of the first mirror (111), the second mirror (113) and the beam splitter (112). The first rotating column (208) and the second reflecting mirror (113) are connected by the synchronous belt (212) sleeved on the outer surfaces of the first transmission disc (211) and the second transmission disc (207); The second rotating column (209) and the light splitting mirror (112) are connected by the synchronous belt (212) sleeved on the outer surfaces of the first transmission disc (211) and the second transmission disc (207); The third rotating column (210) and the first reflecting mirror (111) are connected by the synchronous belt (212) sleeved on the outer surfaces of the first transmission disc (211) and the second transmission disc (207).

6. The high precision gauge block automatic measuring device based on dual-wavelength phase-shifting interferometry according to claim 5, characterized in that: The outer surfaces of the first rotating column (208), the second rotating column (209) and the third rotating column (210) are fixedly provided with hand wheels (204), the outer surfaces of the hand wheels (204) are fixedly provided with convex teeth at equal intervals, the convex teeth on the outer surfaces of the three groups of hand wheels (204) can be embedded into one corner of the V-shaped plates (203) at intervals, the three groups of V-shaped plates (203) are rotatably arranged in the ovoid frame (202), and the ovoid frame (202) is fixedly arranged on one end of the upper surface of the heat preservation box (1).

7. The high precision gauge block automatic measuring device based on dual-wavelength phase-shifting interferometry according to claim 6, characterized in that: The ovoid frame (202) is provided with a sliding slot (213) at one end, the sliding slot (213) is slidably provided with a tapered block (205), one end of the tapered block (205) is fixedly connected with one end of a spring (206), and the other end of the spring (206) is fixedly connected with the other end of the sliding slot (213); The spring (206) applies a spring pushing force to the tapered block (205), so that the tapered block (205) abuts against one end of the three groups of V-shaped plates (203), and one corner of the three groups of V-shaped plates (203) is rotated and clamped into the interval of the convex teeth of the hand wheel (204).

8. The high precision gauge block automatic measuring device based on dual-wavelength phase-shifting interferometry according to claim 7, characterized in that: The hand wheel (204) and the V-shaped plate (203) are elastically clamped and matched to form a limiting structure similar to a ratchet wheel, so that the hand wheel (204) is prevented from being accidentally deflected.

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