Precise scanning measuring head based on geometrical optics and measuring method

Abstract

The invention relates to the technical field of precision measurement, and discloses a precision scanning measuring head based on geometrical optics and a measuring method. Through the geometrical optics progressive increase amplification principle of a heterogeneous prism group, the measurement resolution is improved, tiny mechanical displacement is converted into multiple amplification of an optical path, and the measurement precision is improved. The equivalent optical gain far exceeds the electronic subdivision capability of a traditional grating, the position sensitive detector provides rapid and high-resolution light spot position detection capability, the common-mode noise is effectively suppressed by the symmetrical differential structure, the signal-to-noise ratio, the anti-interference capability and the long-term drift performance are remarkably improved, ultrahigh-precision measurement can be stably realized in an actual environment, and the measurement precision is greatly improved. The precise scanning head is simple in structure, the manufacturing difficulty and cost are remarkably reduced, and optical and mechanical structures are easier to process, assemble and integrate.

Description

Technical Field

[0001] This invention relates to the field of precision measurement technology, and in particular to a precision scanning probe and measurement method based on geometric optics. Background Technology

[0002] As a core sensor in modern high-end manufacturing equipment (such as coordinate measuring machines and precision CNC machine tools), the precision scanning probe's measurement accuracy directly determines the performance level of the entire system, making it an indispensable key component in precision manufacturing, micro-nano fabrication, and scientific research. Currently, mainstream non-contact or contact high-precision probes generally employ sensor technology based on grating interference or moiré fringe principles. Their typical working principle is as follows: a tiny displacement to be measured is transmitted to a pair of precision grating scales using optical or mechanical structures. By detecting the periodic changes in the light signal generated by the relative motion of the gratings, the displacement is calculated after photoelectric conversion and electronic subdivision processing. This type of technology has matured relatively quickly over a long period of development.

[0003] However, this technology, based on traditional grating sensors, faces fundamental bottlenecks in further improving measurement accuracy. First, its measurement resolution and accuracy are fundamentally dependent on the grating ruler's scribing density and manufacturing quality. The grating scribing spacing determines the theoretical limit of measurement resolution, and to achieve higher resolution, denser and more uniform lines must be etched. This is limited by the limits of core processing technologies such as ultra-precision lithography and diffraction. As the linewidth approaches physical limits, the complexity of the process and manufacturing costs increase exponentially, making the manufacture of high-density, large-size, defect-free gratings extremely difficult and expensive. Second, the system's accuracy heavily depends on the manufacturing errors of the grating ruler (such as scribing spacing error, cumulative error, and deformation) and the stability and anti-interference capability of the subsequent electronic subdivision circuit. To compensate for these errors, complex compensation algorithms and temperature control systems are often required, further increasing the system's complexity and cost. Summary of the Invention

[0004] The purpose of this invention is to address the technical problem that the measurement accuracy cannot be further improved due to limitations in the manufacturing process of precision scanning probes, and to provide a precision scanning probe and measurement method based on geometric optics.

[0005] To achieve the above-mentioned objectives, the embodiments of the present invention provide the following technical solutions:

[0006] A precision scanning probe based on geometric optics includes a measuring component, a laser, and a driving circuit. The measuring component is used to measure the displacement of a workpiece, the laser is used to emit laser light, and the driving circuit is used to supply power and transmit signals. The probe is characterized by further including an upper heterogeneous triangular prism group, a lower heterogeneous triangular prism group, an elastic reset component, and a position-sensitive detector.

[0007] When the measuring components are not working, the upper heterogeneous prism group, the lower heterogeneous prism group, the laser, and the position-sensitive detector form a zero-point symmetrical differential structure.

[0008] When the measuring component is working, the elastic reset component drives the lower heterogeneous prism group to move. The laser emitted by the laser is amplified and reflected by the upper and lower heterogeneous prism groups to the position-sensitive detector, and the position-sensitive detector outputs a differential analog signal.

[0009] To address the technical problem of limiting measurement accuracy due to the processing technology of precision scanning probes, this application employs the geometric optical incremental amplification principle of heterogeneous right-angle reflecting prism groups. Using upper and lower heterogeneous triangular prism groups to form a unique optical path reflecting cavity, the minute mechanical displacement to be measured is converted into multiple reflections of the laser beam within the prism group through a carefully designed optical path. A tiny input displacement is transformed into a significantly amplified displacement corresponding to the output light spot, achieving physical amplification of the displacement signal. This breaks away from the traditional technical path of relying on increasing the density of grating lines to improve accuracy, overcoming the limitations of grating processing technology. By introducing a position-sensitive detector as a non-grating displacement detection unit, the detection of the spot center has extremely high resolution and response speed. It can accurately capture the movement of tiny spots magnified by the prism group and efficiently convert the optical amplification signal into an electrical signal. A symmetrical optical layout formed by the laser, heterogeneous prism group and position-sensitive detector is constructed at the initial zero point position. Combined with the differential signal output mode of the position-sensitive detector itself, it can effectively suppress common-mode interference such as light source intensity fluctuations and electronic circuit drift, which significantly improves the stability and signal-to-noise ratio of the measurement. This provides a guarantee for achieving high-precision measurement and solves the technical problem that traditional precision scanning probes cannot further improve measurement accuracy due to the limitations of grating processing technology.

[0010] Compared with existing technologies, the beneficial effects of this application are as follows: by using the geometric optical incremental amplification principle of heterogeneous prism group, the measurement resolution is improved, and the minute mechanical displacement is converted into an optical path multiple amplification, so that the equivalent optical gain far exceeds the electronic subdivision capability of traditional grating. The position sensitive detector provides fast and high-resolution spot position detection capability. The symmetrical differential structure effectively suppresses common-mode noise, significantly improves the signal-to-noise ratio, anti-interference capability and long-term drift performance, so that ultra-high precision measurement can be stably realized in the actual environment. The precision scanning head has a simple structure, which significantly reduces the manufacturing difficulty and cost. The optical and mechanical structures are easier to process, assemble and integrate, avoiding expensive ultra-precision photolithography process and complex compensation system.

[0011] Furthermore, a precision scanning probe based on geometric optics, the scanning probe further includes an outer frame, an upper fixing frame, a lower support, and an outer frame;

[0012] The outer frame is used to fix the drive circuit, the upper fixing frame, and the lower support.

[0013] The upper fixing frame is used to fix the upper heterogeneous triangular prism assembly;

[0014] The lower support is used to connect the lower heterogeneous triangular prism assembly via an elastic reset component.

[0015] The above-described solution addresses the technical problem in existing technologies where the elastic reset component, being directly connected to the moving assembly and fixed base, is susceptible to installation stress, friction, and misalignment, resulting in low reset accuracy, hysteresis error, and lateral interference, thus hindering overall measurement accuracy and stability. This application addresses this issue by providing a stable reference for the entire system through its outer frame. The upper fixed frame ensures the absolute fixation of the upper heterogeneous prism group, forming a constant reference end for the optical path. The lower support acts as a crucial motion intermediary, optimizing the connection between the lower heterogeneous prism group and the elastic reset component. This ensures the transmission path of the reset force is highly aligned with the expected motion axis, solving the problems of low reset accuracy, hysteresis error, and lateral interference. This application, by combining a rigid outer frame, a fixed upper fixed frame, and an elastic reset guided by the lower support, provides an extremely stable and precisely moving mechanical environment for optical amplification and position-sensitive detectors. It isolates the effects of external mechanical vibration and stress, further ensuring that the motion driven by the elastic reset component is a strictly repeatable linear displacement, significantly reducing hysteresis error and lateral interference.

[0016] Furthermore, a precision scanning probe based on geometric optics, wherein the upper heterogeneous prism group is used to receive laser light emitted by a laser.

[0017] The lower heterogeneous prism group is used to receive the laser reflected by the upper heterogeneous prism group;

[0018] The position-sensitive detector is used to receive the laser reflected by the lower heterogeneous prism group.

[0019] Furthermore, a precision scanning probe based on geometric optics includes a central heterogeneous prism pair receiving laser light reflected from an edge heterogeneous prism pair, an edge heterogeneous prism pair receiving laser light reflected from a central heterogeneous prism pair, and a position-sensitive detector receiving laser light reflected from an edge heterogeneous prism pair.

[0020] The existing technology suffers from several problems, including unclear functional definitions of optical components in the optical path structure and non-unique or non-closed optical signal transmission paths. These issues lead to unexpected stray reflections, energy loss, and deterioration of the laser beam's spot quality during transmission, severely interfering with the signal quality of the position-sensitive detector and ultimately limiting measurement accuracy and reliability. This application addresses these problems by clearly defining the cascaded functional relationship between the upper heterogeneous prism group, the lower heterogeneous prism group, and the position-sensitive detector, constructing a unidirectional, defined, and closed high-efficiency optical signal transmission chain. Specifically, the upper heterogeneous prism group receives and initially deflects the laser beam. The lower heterogeneous prism group receives the laser beam from the upper group and performs subsequent multiple reflections and amplifications. The position-sensitive detector receives the laser spot emitted from the lower group, which has undergone displacement amplification, thus precisely defining the starting point, core amplification path, and ending point of the optical path. This application, by combining an upper heterogeneous prism group for receiving at the front end, a lower heterogeneous prism group for amplification in the middle, and a position-sensitive detector for detection at the end, ensures that the core principle of incremental amplification based on geometric optics can be accurately and reliably physically realized. It eliminates non-functional reflections and stray light in the optical path, ensures efficient utilization of laser energy and purity of the light spot quality, provides a high-intensity, low-noise input signal for the position-sensitive detector, and ensures high accuracy, high repeatability, and strong anti-interference capability of the overall measurement of the probe.

[0021] Furthermore, a precision scanning probe based on geometric optics, wherein the upper heterogeneous prism group includes a central upper heterogeneous prism and an edge upper heterogeneous prism pair;

[0022] The lower heterogeneous prism group includes a central lower heterogeneous prism pair and an edge lower heterogeneous prism pair.

[0023] Furthermore, a precision scanning probe based on geometric optics is provided, wherein the zero-point symmetrical differential structure is formed by symmetrically arranging the upper heterogeneous prism group and the lower heterogeneous prism group, with the laser fixed below the central upper heterogeneous prism and position-sensitive detectors respectively arranged above the edge upper heterogeneous prisms.

[0024] The above-mentioned solutions address the technical problems of existing single-path optical signal detection structures, which are susceptible to light source fluctuations, electronic drift, and environmental interference, resulting in low signal-to-noise ratio, poor long-term stability, and inability to reliably detect minute displacement changes. Specifically, traditional non-differential structures lack common-mode rejection capabilities, with system noise directly superimposed on the measurement signal, becoming a key bottleneck restricting further accuracy improvements. This application, by strictly limiting the symmetrical arrangement of the upper and lower heterogeneous prism groups and precisely fixing the geometric positions of the laser and position-sensitive detectors relative to the central and edge prisms, physically constructs a complete zero-point symmetrical differential structure. This structure achieves dual-path mirror symmetry in the optical path, allowing the light emitted by the laser to be synchronously received by two symmetrically arranged position-sensitive detectors after passing through the symmetrical prism group, forming a natural basis for electrical differential signal output. This application achieves a highly stable differential measurement mechanism at the physical level by combining a symmetrical prism group, a centrally located laser source, and a symmetrical detector. This greatly suppresses common-mode interference (such as changes in light source intensity and temperature drift) in the two signal paths, while effectively amplifying the differential signal caused by micro-displacement. This improves the effective resolution and long-term stability to a level that is difficult to achieve with traditional single-path structures, and significantly reduces the stringent requirements for external environmental stability. This is the key to achieving ultra-high precision and ultra-high reliability in this application.

[0025] A measurement method for a precision scanning probe based on geometric optics includes a non-working state and a working state of the measuring component;

[0026] When the measuring component is not in operation, the optical path is symmetrical, the two position-sensitive detectors receive symmetrical light spots, and the differential output is zero.

[0027] When the measuring component is in working condition, it is displaced when in contact with the workpiece, the optical path is asymmetrical, the positions of the light spots of the two position-sensitive detectors change, and a differential analog signal is output. The displacement of the measuring component is calculated through the differential analog signal.

[0028] The existing technologies described above are fundamentally limited by the physical grating pitch and periodic signal processing of the grating, resulting in insurmountable theoretical and technological hurdles to improving accuracy. They require converting displacement into periodic moiré or interference fringes, followed by complex electronic signal subdivision and counting to obtain results. This not only makes the system complex and costly but also extremely sensitive to environmental vibrations, temperature drift, and electronic noise, ultimately limiting further improvements in measurement accuracy, stability, and response speed. This application, by distinguishing between inactive and active states and defining a symmetrical optical path with zero differential output as a self-calibration benchmark, directly converts displacement into an asymmetrical optical path with a differential analog signal. This novel measurement process, centered on geometric optical amplification and analog differential detection, replaces the traditional periodic grating signal and electronic subdivision. This application, by combining a self-calibration benchmark based on a symmetrical optical path, direct displacement-optical signal conversion based on optical path asymmetry, and high signal-to-noise ratio solution based on analog differential signals, abandons the dependence on physical grating distance and complex signal processing chains. It directly extracts displacement information through optical amplification and analog differential, which not only breaks through the limits of traditional accuracy in principle and greatly simplifies the measurement system, but also significantly improves anti-interference capability and response speed, providing a brand-new methodological path for achieving ultra-high precision and high stability micro-displacement measurement.

[0029] Furthermore, a measurement method for a precision scanning probe based on geometric optics, wherein the displacement of the measuring component is calculated using a differential analog signal, using the following formula:

[0030] ;

[0031] in, For the position-sensitive detector (5) to measure the displacement, k is the number of times the laser oscillates and reflects between the upper heterogeneous prism group (2) and the lower heterogeneous prism group (3). To measure the displacement of the component.

[0032] The existing technology relies on complex electronic subdivision and phase counting models for displacement calculation. The calculation formula is strongly correlated with multiple parameters such as the physical grating pitch, electronic subdivision factor, and signal phase. This not only results in complex models and susceptibility to electronic noise interference, but also limits accuracy improvement due to physical bottlenecks such as grating pitch reduction and electronic subdivision capability saturation. This application establishes a deterministic and simple linear amplification relationship by adding the number of reflections k between the measured displacement and the displacement detected by the position-sensitive detector. It replaces the traditional statistical and periodic calculation methods that rely on electronic signal processing with deterministic physical amplification based on geometric optics. By simplifying the measurement process from complex multi-parameter electronic signal processing to a highly deterministic physical amplification process determined solely by the optical structure, this application greatly simplifies system calibration and displacement inverse calculation, and fundamentally ensures linearity, predictability, and anti-interference capability. This is a direct mathematical manifestation of the geometric optics amplification principle of this invention.

[0033] Furthermore, a measurement method for a precision scanning probe based on geometric optics also includes setting a displacement threshold for the measuring component, the steps of which are as follows:

[0034] When the displacement of the measuring component reaches a preset threshold, the system switches from the measuring component working state to the threshold alarm trigger state, and stops the measuring component from working.

[0035] The existing technologies typically rely on subsequent circuits or software to judge the displacement calculation results, resulting in a long response chain. Furthermore, they may fail to identify physical overtravel risks in a timely and accurate manner when signals are saturated or abnormal, leading to probe damage or measurement failure due to overload. This application solves the problem of long response chains caused by judging displacement calculation results by setting a displacement threshold and defining the switch from the operating state of the measuring component to the trigger threshold alarm state. When the displacement ΔX corresponding to the differential analog signal caused by optical path asymmetry reaches the preset physical threshold, the state is immediately switched and an alarm is issued, stopping operation. This application combines the physical displacement threshold setting based on optical amplification principles with the direct switching mechanism from the operating state to the alarm state, directly responding to the raw displacement information generated by the core optical path without complex processing. The response speed is extremely fast, fundamentally avoiding protection failures caused by electronic processing delays and ensuring that the measurement always operates within its designed linear and high-precision range. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a structural diagram of a precision scanning probe based on geometric optics.

[0038] Figure 2 This is a schematic diagram of the laser trajectory of the prism assembly.

[0039] Figure 3 This is a schematic diagram of the laser trajectory when the measurement component is not in operation.

[0040] In the diagram, 1-laser, 2-upper heterogeneous prism group, 3-lower heterogeneous prism group, 4-reed, 5-position sensitive detector, 6-drive circuit, 7-probe rod, 8-probe head, 9-outer frame, 10-upper fixing frame, 11-lower support, 21-center upper heterogeneous prism, 22-edge upper heterogeneous prism pair, 31-center lower heterogeneous prism pair, 32-edge lower heterogeneous prism pair. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0042] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance, or suggesting any such actual relationship or order between these entities or operations. Additionally, the terms "connected," "linked," etc., can refer to a direct connection between elements or an indirect connection via other elements. Zero-point symmetric differential structure.

[0043] Example 1: A precision scanning probe based on geometric optics.

[0044] like Figure 1 As shown, a precision scanning probe based on geometric optics includes a measuring component, a laser 1, and a driving circuit 6. The measuring component includes a measuring rod 7 and a measuring head 8. The measuring rod 7 and the measuring head 8 are combined to measure the displacement of a workpiece. The laser 1 is used to emit laser light. The driving circuit is used to supply power and transmit signals. It also includes an upper heterogeneous triangular prism group 2, a lower heterogeneous triangular prism group 3, a reed 4, and a position-sensitive detector 5.

[0045] When the measuring components are not working, the upper heterogeneous triangular prism group 2, the lower heterogeneous triangular prism group 3, the laser 1, and the position-sensitive detector 5 form a zero-point symmetrical differential structure.

[0046] When the measuring component is working, the reed 4 drives the lower heterogeneous triangular prism group 3 to move. The laser 1 emits a laser beam, which is amplified and reflected by the upper heterogeneous triangular prism group 2 and the lower heterogeneous triangular prism group 3 to the position sensitive detector 5. The position sensitive detector 5 outputs a differential analog signal.

[0047] like Figure 2 As shown, specifically, the upper heterogeneous prism group 2 includes a central upper heterogeneous prism 21 and an edge upper heterogeneous prism pair 22; the lower heterogeneous prism group 3 includes a central lower heterogeneous prism pair 31 and an edge lower heterogeneous prism pair 32.

[0048] When the measuring component is not working, the upper heterogeneous prism group 2 and the lower heterogeneous prism group 3 are symmetrically arranged. The laser 1 is fixed below the central upper heterogeneous prism 21. Two position-sensitive detectors 5 are respectively arranged above the edge upper heterogeneous prism pair 22. The position-sensitive detectors 5 are fixed below the driving circuit 6. The central upper heterogeneous prism 21 is arranged above the gap between the central lower heterogeneous prism pair 31. The central lower heterogeneous prism pair 31 has the same shape, the edge lower heterogeneous prism pair 32 has the same shape, and the edge upper heterogeneous prism pair 22 has the same shape.

[0049] When the measuring component is working, the probe 8 drives the probe rod 7 to move, thereby driving the reed 4 to move, causing the lower heterogeneous prism group 3 to be displaced. The heterogeneous prism group 2 and the lower heterogeneous prism group 3 are no longer symmetrical, that is, the upper heterogeneous prism group 2, the lower heterogeneous prism group 3, the laser 1, and the position sensitive detector 5 no longer form a zero-point symmetrical differential structure.

[0050] Specifically, the scanning probe also includes an outer frame 9, an upper fixing frame 10, and a lower support 11. The outer frame 9 is used to fix the driving circuit 6, the upper fixing frame 10, the lower support 11, and the laser 1. The upper fixing frame 10 is used to fix the upper heterogeneous triangular prism group 2. The lower support 11 is used to connect the lower heterogeneous triangular prism group 3 through the elastic reset component 4. The upper fixing frame 10 and the fixed driving circuit 6 are fixedly connected.

[0051] Specifically, the upper heterogeneous prism group 2 is used to receive the laser emitted by the laser 1; the lower heterogeneous prism group 3 is used to receive the laser reflected by the upper heterogeneous prism group 2; and the position-sensitive detector 5 is used to receive the laser reflected by the lower heterogeneous prism group 3.

[0052] like Figure 3 As shown, when the measuring component is not working, the laser emitted by the laser 1 of the central heterogeneous prism 21 is reflected by the central heterogeneous prism 21 to the edge heterogeneous prism pair 22, the edge heterogeneous prism pair 22 to the central lower heterogeneous prism pair 21, the central lower heterogeneous prism pair 21 to the edge lower heterogeneous prism pair 32, and the edge lower heterogeneous prism pair 32 to the two position-sensitive detectors 5. The optical paths formed by the lasers are completely symmetrical, that is, the laser energy received by the position-sensitive detectors 5 is equal.

[0053] When the measuring component is working, the laser emitted by the laser 1 of the central heterogeneous prism 21 is reflected by the central heterogeneous prism 21 to the heterogeneous prism pair 22 on the edge. As the probe 8 drives the probe rod 7 to move, it drives the reed 4 to move, causing the lower heterogeneous prism group 3 to shift. This causes the position of the laser reflected onto the central lower heterogeneous prism pair 31 to change, resulting in a continuous and symmetrical movement of the light spot position projected on the two position sensitive detectors 5, which is reflected by the output differential analog signal.

[0054] The laser is geometrically amplified by reflection from the upper heterogeneous prism group 2 and the lower heterogeneous prism group 3. The specific principle is that photons can oscillate back and forth between the upper heterogeneous prism group 2 and the lower heterogeneous prism group 3, continuously inducing the generation of new photons, thereby achieving light amplification.

[0055] Example 2: A measurement method for a precision scanning probe based on geometric optics.

[0056] A measurement method for a precision scanning probe based on geometric optics includes a non-working state and a working state of the measuring component;

[0057] When the measuring component is not working, the optical path is symmetrical, the two position-sensitive detectors 5 receive symmetrical light spots, and the differential output is zero.

[0058] When the measuring component is in working condition, it is displaced when in contact with the workpiece, the optical path is asymmetrical, the positions of the light spots of the two position sensitive detectors 5 change, and differential analog signals are output. The displacement of the measuring component is calculated through the differential analog signals.

[0059] Specifically, when the measuring component is not in operation, the laser 1 emits a laser beam, which is reflected and split by the upper heterogeneous prism group 2 and the lower heterogeneous prism group 3. The beam is designed into two completely symmetrical optical paths, which are respectively injected into two position-sensitive detectors 5. Each of the two position-sensitive detectors 5 forms a light spot on its detection surface. The light spots reaching the two position-sensitive detectors 5 have the same intensity. The energy center formed by the two light spots is located on the axis of symmetry of the optical measurement. When the two position-sensitive detectors 5 receive light spots with equal intensity and symmetrical positions, the electrical signals output by the two position-sensitive detectors 5 are equal in magnitude but opposite in polarity. The differential amplifier processes the signals, and the final output signal is zero.

[0060] Specifically, when the measuring component is in working condition, the measuring component makes a slight displacement when it contacts the workpiece. This displacement causes the lower heterogeneous triangular prism group 3 to move along with the reed 4, disrupting the original symmetry of the optical path. The change in the optical path causes the light spots of the two position-sensitive detectors 5 to no longer be symmetrical and equal. The movement of the light spot of one position-sensitive detector 5 increases, while the movement of the light spot of the other position-sensitive detector 5 decreases (or moves in the opposite direction). The differential signal output by the two position-sensitive detectors 5 is no longer zero. By measuring the differential signal, the displacement of the measuring component is calculated.

[0061] A measurement method based on a precision scanning probe using geometric optics, wherein the displacement of the measuring component is calculated using a differential analog signal, using the following formula:

[0062] ;

[0063] in, For the position-sensitive detector (5) to measure the displacement, k is the number of times the laser oscillates and reflects between the upper heterogeneous prism group (2) and the lower heterogeneous prism group (3). To measure the displacement of the component.

[0064] Specifically, the magnitude of the differential signal is measured, and the displacement is measured by the position-sensitive detector 5. Proportional to, and therefore to, the displacement of the measuring component. Proportional to the moment when probe 8 contacts the workpiece and undergoes a minute displacement. When the measuring rod 7 moves, it moves via the reed 4, which in turn moves the lower heterogeneous triangular prism assembly 3, thus measuring the displacement of the measuring component. The displacement of the lower heterogeneous prism group 3 is amplified to the position of the light spot on the photosensitive surface of the position-sensitive detector 5 through k reflections. Larger displacement (based on the principle of incremental amplification in geometric optics).

[0065] A measurement method for a precision scanning probe based on geometric optics further includes setting a displacement threshold for the measuring component, the steps of which are as follows:

[0066] When the displacement of the measuring component reaches a preset threshold, the system switches from the measuring component working state to the threshold alarm trigger state, and stops the measuring component from working.

[0067] Specifically, when measuring the displacement of the component When the preset threshold is exceeded, the change in the optical path will cause one light spot to completely move out of the position-sensitive detector 5. That is, one of the position-sensitive detectors 5 will suddenly lose its signal after it has been detected. When the signal of the position-sensitive detector 5 disappears at this time, it indicates that the displacement of the measuring component has occurred. The preset threshold has been reached, and the optical path has deviated significantly.

[0068] The threshold is rigidly determined by the optical structure, making it very stable and precise, and unaffected by analog circuit drift or amplification factor.

[0069] In some embodiments, the positions of the upper heterogeneous prism group 2 and the lower heterogeneous prism group 3 can be interchanged, and the two position-sensitive detectors 5 are respectively set below the lower heterogeneous prism pair 32 at the edge. The driving circuit 6 is also adjusted. At this time, the laser 1 shines downwards, and the optical path can be symmetrical when the measuring component is not working.

[0070] In some embodiments, the resilient reset component may also be a flexible hinge, which utilizes the elastic deformation of thin-walled regions of a specific shape formed by wire cutting or etching on a single piece of material to achieve guidance and movement.

[0071] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A precision scanning probe based on geometric optics, comprising a measuring component, a laser (1), and a driving circuit (6), wherein the measuring component is used to measure the displacement of a workpiece, the laser (1) is used to emit laser light, and the driving circuit is used to supply power and transmit signals, characterized in that, It also includes an upper heterogeneous prism group (2), a lower heterogeneous prism group (3), an elastic reset component, and a position-sensitive detector (5); When the measuring components are not working, the upper heterogeneous prism group (2), the lower heterogeneous prism group (3), the laser (1), and the position-sensitive detector (5) form a zero-point symmetrical differential structure. When the measuring component is working, the elastic reset component drives the lower heterogeneous prism group (2) to move. The laser (1) emits a laser beam, which is amplified and reflected by the upper heterogeneous prism group (2) and the lower heterogeneous prism group (3) to the position sensitive detector (5). The position sensitive detector (5) outputs a differential analog signal.

2. The precision scanning probe based on geometric optics according to claim 1, characterized in that, The scanning probe also includes an outer frame (9), an upper fixing frame (10), a lower support (11), and an outer frame (9). The outer frame (9) is used to fix the drive circuit (6), the upper fixing frame (10), and the lower support (11). The upper fixing frame (10) is used to fix the upper heterogeneous triangular prism assembly (2); The lower support (11) is used to connect the lower heterogeneous triangular prism assembly (3) via an elastic reset component.

3. The precision scanning probe based on geometric optics according to claim 1, characterized in that, The upper heterogeneous prism group (2) is used to receive the laser emitted by the laser (1); The lower heterogeneous prism group (3) is used to receive the laser reflected by the upper heterogeneous prism group (2); The position-sensitive detector (5) is used to receive the laser reflected by the heterogeneous prism group (3).

4. The precision scanning probe based on geometric optics according to claim 1, characterized in that, The heteromorphic prism group (2) includes a central heteromorphic prism (21) and an edge heteromorphic prism pair (22). The lower heterogeneous prism group (3) includes a central lower heterogeneous prism pair (31) and an edge lower heterogeneous prism pair (32).

5. A precision scanning probe based on geometric optics according to claim 4, characterized in that, The zero-point symmetrical differential structure consists of the upper heterogeneous prism group (2) and the lower heterogeneous prism group (3) symmetrically arranged, with the laser (1) fixed below the central upper heterogeneous prism (21) and position-sensitive detectors (5) respectively set directly above the edge upper heterogeneous prism pair (22).

6. A precision scanning probe based on geometric optics according to claim 5, characterized in that, The central heterogeneous prism pair (21) receives the laser reflected by the edge heterogeneous prism pair (22), the edge heterogeneous prism pair (32) receives the laser reflected by the central heterogeneous prism pair (21), and the position-sensitive detector (5) receives the laser reflected by the edge heterogeneous prism pair (32).

7. A measurement method for a precision scanning probe based on geometric optics, characterized in that, This includes both the non-operational state and the operational state of the measuring component; When the measuring component is not in operation, the optical path is symmetrical, and the two position-sensitive detectors (5) receive symmetrical light spots, with a differential output of zero. When the measuring component is in working state, the measuring component is in contact with the workpiece and is displaced. The optical path is asymmetrical, and the position of the light spot of the two position sensitive detectors (5) changes. The differential analog signal is output, and the displacement of the measuring component is calculated through the differential analog signal.

8. The measurement method of a precision scanning probe based on geometric optics according to claim 7, characterized in that, The formula for calculating the displacement of the measuring component using differential analog signals is as follows: ； in, For the position-sensitive detector (5) to measure the displacement, k is the number of times the laser oscillates and reflects between the upper heterogeneous prism group (2) and the lower heterogeneous prism group (3). To measure the displacement of the component.

9. The measurement method of a precision scanning probe based on geometric optics according to claim 7 further includes setting a displacement threshold for the measuring component, the steps of which are: When the displacement of the measuring component reaches a preset threshold, the system switches from the measuring component working state to the threshold alarm trigger state, and stops the measuring component from working.

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