A compound light path shaping type complex smooth surface global displacement measurement device

Abstract

The application discloses a kind of complex light path shaping type complex smooth surface global displacement measuring devices, it includes laser transmitter, beam adjusting unit and detection unit, the laser transmitter, beam adjusting unit and detection unit are sequentially arranged along light path;The beam adjusting unit includes linear diffusion sheet, multiple diffusion parts are protruded on the linear diffusion sheet, the diffusion part is used to diffuse light to the workpiece to be measured, to adapt the curvature variation area on the smooth surface of the workpiece to be measured, the detection unit is located on the reflected light path after light via the workpiece to be measured.This application adjusts the light beam angle by the beam adjusting unit to adapt to the workpiece, realizes the accurate measurement to the complex smooth surface of workpiece.

Description

Technical Field

[0001] This application relates to the field of optical measurement technology, and in particular to a composite optical path type complex smooth surface global displacement measurement device. Background Technology

[0002] Currently, laser displacement sensors and laser profile sensors commonly use triangulation, where a laser beam emitted by a laser diode illuminates the surface of the object being measured. The light, after diffuse reflection, passes through a set of lenses and is finally projected onto the detection unit. Depending on the distance to the surface of the object being measured and the laser source, the imaging position on the detection unit will also vary, thereby confirming the surface displacement of the object being measured.

[0003] In line structured light measurement, a laser beam emitted from a laser is expanded by a cylindrical lens and then collimated to produce a sheet-like beam. This beam cuts across the surface of the object being measured like a knife edge; therefore, line structured light is also known as optical cutting. Line structured light measurement often uses a two-dimensional area CCD as the receiving device; therefore, by adding a third dimension perpendicular to the area detector, the measurement of three-dimensional objects can be achieved.

[0004] Traditional line laser triangulation is typically used for measuring the general diffuse reflective surfaces of workpieces, where the rough diffuse reflective surface diffuses the line laser beam to the detection unit. However, in actual working conditions, many workpieces have smooth surfaces to be measured, also known as specular surfaces, which will cause specular reflection of the incident laser. For measuring smooth surfaces, the angle of the reflected beam after the laser shines on the smooth surface is very limited. Usually, there are strict restrictions on the positions of the light source, workpiece, and photosensitive unit to ensure that the light is effectively reflected to the detection unit after it hits the smooth surface of the workpiece.

[0005] However, many workpieces have smooth surfaces with complex structures, made of smooth materials, and with many free-form surfaces and irregular inclined surfaces. When measuring these complex smooth surfaces, traditional displacement sensors cannot match the changes in the tilt angle of the workpiece surface, resulting in problems such as loss of reflected light and broken stripes, thus failing to complete effective measurements. Summary of the Invention

[0006] To address the problem that existing displacement sensors are not suitable for measuring complex, smooth surfaces of workpieces, The composite optical path type complex smooth surface global displacement measuring device provided in this application adopts the following scheme: A composite optical path type complex smooth surface full-range displacement measurement device includes: a laser emitter, a beam adjustment unit, and a detection unit, wherein the laser emitter, the beam adjustment unit, and the detection unit are arranged sequentially along the optical path; the beam adjustment unit includes a linear diffuser, and the linear diffuser has multiple protruding diffuser portions, which are used to diffuse light to the curvature change region on the smooth surface of the workpiece being measured; the detection unit is located on the reflected light path after the light passes through the workpiece being measured.

[0007] Optionally, a collimation unit is also included, which is disposed between the laser emitter and the beam adjustment unit, and is used to collimate the emitted light from the laser emitter and guide it to the beam adjustment unit.

[0008] Optionally, the collimation unit includes a cylindrical Fresnel lens having a smooth surface and a sawtooth surface disposed opposite to each other. The smooth surface faces the laser emitter to receive laser light, and the sawtooth surface faces the beam adjustment unit to direct the collimated beam into the beam adjustment unit.

[0009] Optionally, the number of the cylindrical Fresnel lenses is multiple, and the collimation unit is composed of multiple cylindrical Fresnel lenses arranged side by side along a direction perpendicular to the optical path.

[0010] Optionally, the beam adjustment unit further includes at least one microprism located between the collimating unit and the linear diffuser. The microprism has an inclined surface that is tilted relative to the outgoing light path of the collimating unit. The inclined surface of the microprism is used to deflect the collimated light and refract it toward the corresponding inclined smooth surface on the workpiece being measured.

[0011] Optionally, the at least one microprism may include a plurality of microprisms, which are arranged side by side and together form an integral optical surface.

[0012] Optionally, the multiple microprisms are fixed together by optical adhesive.

[0013] Optionally, the tilted surfaces of the plurality of microprisms have the same or different tilt angles relative to the optical axis direction of the outgoing light path of the collimating unit, and the tilt angle of each microprism corresponds one-to-one with the tilt angle of each tilted smooth surface on the workpiece being tested, so that each microprism refracts the corresponding light to the corresponding tilted smooth surface.

[0014] Optionally, the detection unit includes an imaging module and a photosensitive module arranged sequentially on the optical path after reflection from the workpiece being tested. The imaging module is a lens with a fixed focal length or a lens group with an adjustable focal length.

[0015] Optionally, the photosensitive module is a CMOS chip.

[0016] In summary, this application includes at least one of the following beneficial technical effects: 1. The displacement measuring device of this embodiment effectively solves this problem by introducing a linear diffuser and multiple protruding diffusers in the beam adjustment unit. The diffusers diffuse the light, enabling it to cover the curvature variation areas on the smooth surface of the workpiece being measured. This means that even if the workpiece surface has complex geometry and tilt changes, the diffused light can still be incident on these areas at multiple angles, thereby ensuring that at least a portion of the reflected light can be received by the detection unit. Due to the function of the diffusers, the laser can effectively irradiate the curvature variation areas such as grooves, protrusions, or inclined surfaces of the workpiece being measured, ensuring that the reflected light can be captured by the detection unit, thus avoiding the problems of reflected light loss and stripe breakage common in traditional solutions. In addition, the displacement measuring device of this embodiment can adapt to the measurement requirements of complex smooth surfaces, improve the applicability of the measurement system, and achieve accurate measurement of complex smooth surfaces; 2. Since the cylindrical Fresnel lens is formed by molding, a collimated beam with a relatively large width is required in actual working conditions. Therefore, the length requirement of the cylindrical Fresnel lens in its major axis direction is relatively large. However, in the molding production process, the large size requirement will lead to a sharp increase in cost. Therefore, in the embodiments of this application, multiple cylindrical Fresnel lenses are combined to form a collimation unit, which can effectively reduce the production cost of the collimation unit. 3. In a displacement measuring device for measuring complex smooth surfaces, at least one microprism is introduced, with its inclined surface tilted relative to the optical axis of the collimating unit's output light path. This improvement allows the collimated light to be precisely deflected and refracted, effectively projecting it onto the smooth surfaces of the workpiece with specific tilt angles. Compared to schemes relying solely on linear diffusers for light diffusion, this scheme significantly enhances the sensor's measurement coverage of complex smooth surfaces, especially workpieces containing tilted smooth surfaces. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the displacement measuring device in the embodiments of this application; Figure 2 This is a schematic diagram of the optical path when the workpiece has two inclined smooth surfaces that are symmetrically arranged about the optical path axis reflecting to the detection unit in the embodiments of this application; Figure 3 This is a schematic diagram illustrating the structure and working principle of the linear diffuser in the embodiments of this application; Figure 4 This is a schematic diagram illustrating the structure and working principle of the microprism in the embodiments of this application.

[0018] Explanation of reference numerals in the attached figures: 1. Laser emitter; 2. Beam adjustment unit; 21. Linear diffuser; 211. Diffusion section; 22. Microprism; 3. Detection unit; 31. Imaging module; 32. Photosensitive module; 4. Collimation unit; 41. Cylindrical Fresnel lens. Detailed Implementation

[0019] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0021] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0022] The present application will be further described in detail below with reference to the accompanying drawings.

[0023] In traditional line laser triangulation technology, when the displacement measuring device measures a workpiece with a smooth surface, the angular distribution of the reflected beam is strictly limited due to the specular reflection characteristics. This results in the inability to form an effective imaging point on the detection unit, causing the loss of reflected light and the breakage of stripes, thus affecting the reliability and applicability of the measurement system. This problem stems from the geometric constraint relationship between the change of the workpiece surface tilt angle and the incident light path, which prevents the reflected beam from being effectively incident on the detection unit, resulting in the loss of measurement signal and reducing the system's adaptability to complex smooth surfaces.

[0024] Therefore, this application provides a composite optical path type complex smooth surface full-range displacement measurement device, including a laser emitter 1, a beam adjustment unit 2, and a detection unit 3, wherein the laser emitter 1, the beam adjustment unit 2, and the detection unit 3 are arranged sequentially along the optical path; the beam adjustment unit 2 includes a linear diffuser 21, and the linear diffuser 21 is provided with a plurality of diffuser portions 211, which are used to diffuse light to the curvature change region on the smooth surface of the workpiece being measured; the detection unit 3 is located on the reflected light path after the light passes through the workpiece being measured.

[0025] Specifically, in this embodiment, the laser emitter 1 is used to emit a high-intensity line laser; the beam adjustment unit 2 is used to process the laser beam, deflecting and diffusing the beam. The detection unit 3 is used to receive the light reflected from the workpiece under test and convert it into an electrical signal for subsequent processing. The linear diffuser 21 is an optical element that diffuses incident light in one direction to form a linear or fan-shaped outgoing light; the diffuser portion 211 refers to the microstructure protruding on the linear diffuser 21, used to achieve a specific diffusion effect on the light. The curvature variation region refers to the region on the smooth surface of the workpiece under test that has different degrees of curvature or shape changes; these regions may include grooves, protrusions, inclined surfaces, or freeform surfaces. The reflected light path refers to the entire optical path that the light travels from the surface of the workpiece under test to the detection unit 3.

[0026] The beam adjustment unit 2 includes a linear diffuser 21, which processes the light emitted by the laser emitter 1. In the actual operation of this embodiment, the linear diffuser 21 is made of polymer material; multiple diffusion portions 211 are protruding from the linear diffuser 21, which are microstructures on the linear diffuser 21 used to diffuse the light at a specific angle. In this embodiment, the diffusion portions 211 are small inclined surfaces or arc surfaces with different tilt angles formed by molding process, so as to diffuse the light in different directions. Each diffusion portion 211 corresponds to a region with a changed shape on the smooth surface of the workpiece to be tested. The light diffused by the diffusion portion 211 will diffuse to form a planar diffused light illumination effect with extended light source properties; the diffused light can cover areas with complex shapes or irregular bends on the surface of the workpiece to be tested. For example, when there are grooves or protrusions on the surface of the workpiece to be tested, the diffusion portion 211 can ensure that the light effectively illuminates these areas, avoiding light loss due to the limitation of the specular reflection angle. In another embodiment, the diffuser 211 can generate a fan-shaped light beam with a sufficiently large angle to cover the expected range of curvature changes on the surface of the workpiece being measured. The detection unit 3 is located on the path of the reflected light after it passes through the workpiece, so that the detection unit 3 can receive the light reflected back from the surface of the workpiece. The precise position and angle of the detection unit 3 need to be adjusted according to the characteristics of the workpiece and the measurement range to ensure effective capture of the reflected light.

[0027] In practical applications, when measuring the displacement of a mirror-like workpiece with a complex free-form surface and multiple inclined smooth surfaces, traditional displacement sensors are prone to problems such as lost reflected light or broken stripes due to the multiple curvature variation regions on the workpiece's surface. In conventional techniques, when a laser beam illuminates a mirror-like workpiece with a complex free-form surface or irregular inclined surfaces, the angle of the reflected beam is very limited due to the mirror's reflection characteristics, and the positions of the light source, workpiece, and detection unit 3 are strictly restricted. Once the tilt angle of the workpiece surface changes, the reflected beam easily deviates from the detection unit 3, resulting in lost reflected light and thus preventing effective measurement.

[0028] The operation of the displacement measuring device in this embodiment is as follows: First, the laser emitter 1 emits a laser beam, which then enters the beam adjustment unit 2. The linear diffuser 21 in the beam adjustment unit 2 has multiple diffuser sections 211 protruding to process the incident laser. Specifically, these diffuser sections 211 diffuse the laser beam into a fan-shaped beam with a specific coverage angle. When multiple such fan-shaped beams irradiate the complex smooth surface of the workpiece being measured, even if the workpiece surface has free-form surfaces, irregular inclined surfaces, or areas of varying curvature, the light can effectively cover these areas. For example, when the light irradiates a groove or an inclined surface on the workpiece surface, the diffused light can be incident at different angles, thereby ensuring that at least a portion of the light can be reflected back to the direction of the detection unit 3, so that the detection unit 3 can effectively receive and detect the light. It should be noted that a larger coverage angle does not necessarily mean better detection results. For example, if a conventional linear diffuser 21 is used to simply diffuse the light into diffuse reflection, although the coverage angle increases, the intensity of the light received by the detection unit 3 is often insufficient, leading to a decrease in measurement performance. In this embodiment, by precisely adapting the angle of each diffuser 211 to the curvature variation area of ​​the workpiece surface, it ensures effective coverage of the complex curved surface by the light and maintains sufficient intensity of the incident light, so that the light reflected back to the detection unit 3 from the curvature variation area can form a clear and usable light spot.

[0029] After being reflected from the surface of the workpiece, the light propagates along the reflected light path and is eventually received by the detection unit 3. In actual operation, the detection unit 3 can calculate the displacement data of the workpiece surface based on the position and intensity information of the received reflected light. Because the diffuser 211 diffuses the light to the curvature variation region, even if the workpiece surface has specular reflection characteristics and complex geometry, the detection unit 3 can still receive sufficient light signals, avoiding measurement failures caused by the loss of reflected light in traditional solutions. In this way, the displacement measuring device can perform effective and stable displacement measurement on complex smooth surfaces. Therefore, the displacement measuring device of this embodiment can effectively solve the problem of measuring complex smooth surfaces.

[0030] In practical applications, the beam emitted by the laser emitter 1 may have a certain divergence angle. If this divergent beam is directly guided to the beam adjustment unit 2, it may lead to a decrease in light energy utilization, affecting the accurate diffusion of light by the beam adjustment unit 2, and thus affecting the measurement accuracy. Therefore, this application further proposes that the displacement measuring device also includes a collimation unit 4, which is disposed between the laser emitter 1 and the beam adjustment unit 2, and is used to collimate the emitted light from the laser emitter 1 and guide it to the beam adjustment unit 2.

[0031] Specifically, the collimation unit 4 is positioned between the laser emitter 1 and the beam adjustment unit 2. This arrangement ensures that the collimation unit 4 can receive the raw beam from the laser emitter 1 and perform collimation preprocessing on the beam before it enters the beam adjustment unit 2. The solution of this application optimizes the beam emitted by the laser emitter 1 before it reaches the beam adjustment unit 2 by introducing the collimation unit 4. Specifically, the beam generated by the laser emitter 1 often has a certain divergence angle due to its inherent physical characteristics. When this beam enters the collimation unit 4, the collimation unit 4 uses its internal optical elements to refract the beam, thereby eliminating or significantly reducing the divergence angle and converting it into a highly parallel beam. Subsequently, this collimated parallel beam is precisely guided to the beam adjustment unit 2. Since the beam entering the beam adjustment unit 2 has been collimated, its light energy distribution is more concentrated and uniform, which allows the linear diffuser 21 and its diffuser section 211 in the beam adjustment unit 2 to diffuse the light more efficiently and accurately to the curvature variation region on the smooth surface of the workpiece being measured. This synergistic effect ensures that the beam adjustment unit 2 can receive high-quality incident light, thereby improving its ability to accurately diffuse the light and laying the foundation for the subsequent detection unit 3 to obtain accurate reflected light signals. In actual operation, the laser emitter 1 can be a semiconductor laser diode with a wavelength of 650nm, whose emitted beam has a divergence angle of about 10 degrees. After passing through the collimation unit 4, it can form a parallel beam with a divergence angle of less than 1 milliradian. This collimated beam is incident on the linear diffuser 21 of the beam adjustment unit 2 with a small divergence angle, ensuring the effective utilization of light energy and the uniformity of the light spot.

[0032] By adding a collimation unit 4 between the laser emitter 1 and the beam adjustment unit 2, the laser beam emitted from the laser emitter 1 with a certain divergence angle can be effectively collimated. This significantly improves the parallelism of the beam entering the beam adjustment unit 2, thereby reducing light energy loss and ensuring that the beam adjustment unit 2 can receive high-quality incident light. Therefore, the linear diffuser 21 and its diffuser section 211 in the beam adjustment unit 2 can more efficiently and uniformly diffuse light to the curvature variation region on the smooth surface of the workpiece being measured, greatly improving the accuracy and reliability of the displacement sensor in measuring complex smooth surfaces, making the measurement results more stable and accurate.

[0033] However, traditional collimating optical elements may suffer from problems such as large size, low light energy utilization, or difficulty in achieving a compact design, which may affect the integration and performance of the entire displacement measurement device. In response, this application further proposes that the collimating unit 4 includes a cylindrical Fresnel lens 41, which has a smooth surface and a sawtooth surface arranged opposite each other. The smooth surface faces the laser emitter 1 to receive laser light, and the sawtooth surface faces the beam adjustment unit 2 to direct the collimated beam into the beam adjustment unit 2.

[0034] Specifically, the cylindrical Fresnel lens 41 is a special optical element whose surface is designed with a series of tiny, zigzag structures extending in one direction to significantly reduce the lens's thickness and weight while maintaining optical performance. It is manufactured using a molding process and made from optical-grade polymer materials. The smooth surface refers to one surface of the cylindrical Fresnel lens 41, which is typically optically flat or has a slight curvature. This smooth surface serves as the lens's incident surface, receiving the raw light beam from the laser emitter 1 and ensuring that light enters the lens with minimal reflection and distortion. The zigzag surface is another surface of the cylindrical Fresnel lens 41, composed of a series of closely spaced tiny prism structures. By precisely designing the tilt angle and spacing of each zigzag, the incident light can be effectively refracted, thereby achieving beam collimation, which will not be elaborated further here. This zigzag surface faces the beam adjustment unit 2 to efficiently emit the collimated beam.

[0035] The solution proposed in this application effectively overcomes the limitations of traditional collimating elements by designing the collimating unit 4 as a cylindrical Fresnel lens 41. Specifically, light from the laser emitter 1 first enters the smooth surface of the cylindrical Fresnel lens 41. This smooth surface serves as the light receiving interface, ensuring that the light can enter the lens interior stably and efficiently. Subsequently, the light passes through the internal structure of the cylindrical Fresnel lens 41 and exits from its serrated surface. The serrated surface is composed of a series of precisely designed micro-prism structures, which can accurately refract the light according to the incident angle, thereby collimating the originally divergent laser beam into a parallel beam. This design allows the collimating unit 4 to maintain high-efficiency collimation capability while significantly reducing its overall size. The collimated beam is guided to the beam adjustment unit 2, providing uniform and parallel incident light for the subsequent linear diffuser 21, so that the beam adjustment unit 2 can stably diffuse the light to the curvature variation region on the smooth surface of the workpiece being measured.

[0036] The tilt angle of the sawtooth can be optimized according to the wavelength of the laser and the required collimation effect to ensure that the parallelism of the emitted beam meets the preset requirements. The size of the cylindrical Fresnel lens 41 can be customized according to the spot size of the laser emitter 1 and the entrance size of the beam adjustment unit 2. For example, in actual operation, the smooth surface and the sawtooth surface of the cylindrical Fresnel lens 41 are respectively at both ends of its own axis, and the optical path passes through the axis of the cylindrical Fresnel lens 41. The effective radial length of the cylindrical Fresnel lens 41 can be matched with the width of the linear diffuser 21 to ensure that the entire beam adjustment unit 2 can receive uniform collimated light.

[0037] By adopting the above technical solution, the collimation unit 4 is designed to include a cylindrical Fresnel lens 41, effectively solving the problems of large size and low light energy utilization of traditional collimating optical elements. The cylindrical Fresnel lens 41, with its unique smooth and serrated surface structure, can significantly reduce the thickness and weight of the collimation unit 4 while maintaining high-efficiency collimation capability, thus enabling a more compact and lightweight design for the entire displacement measurement device. Furthermore, this design improves the collimation efficiency of the laser beam, ensuring that the beam adjustment unit 2 can receive high-quality parallel light, thereby improving the uniformity of light diffusion on the smooth surface of the workpiece and the measurement accuracy.

[0038] In another embodiment, the number of cylindrical Fresnel lenses 41 is multiple, and the collimation unit 4 is composed of multiple cylindrical Fresnel lenses 41 arranged side by side along a direction perpendicular to the optical path. The multiple cylindrical Fresnel lenses 41 mean that the collimation unit 4 is no longer composed of only one cylindrical Fresnel lens 41, but rather two or more cylindrical Fresnel lenses 41. The collimation unit 4 is composed of multiple cylindrical Fresnel lenses 41 arranged side by side, with the long axis of each cylindrical Fresnel lens 41 perpendicular to the optical path. This side-by-side arrangement aims to expand and collimate the incident beam in a direction perpendicular to the optical path, forming a wider collimated light band or sheet. Furthermore, since the cylindrical Fresnel lenses 41 are molded, in this embodiment, due to the need for a wider collimated beam in actual working conditions, a larger length of the cylindrical Fresnel lenses 41 in the direction perpendicular to the optical path is required. In the molding process, larger size requirements can lead to a sharp increase in cost. Therefore, in this embodiment, a collimation unit 4 is formed by combining multiple columnar Fresnel lenses 41, which can effectively reduce the production cost of the collimation unit 4.

[0039] In one specific implementation, the collimation unit 4 can be composed of two cylindrical Fresnel lenses 41. Each independent cylindrical Fresnel lens 41 is formed by a molding process and combined to form a combination with a structure of two cylindrical Fresnel lenses 41. The two cylindrical Fresnel lenses 41 are arranged side by side in a direction perpendicular to the optical path and are closely adjacent to each other to ensure the continuity and uniformity of the beam.

[0040] This application further proposes that the beam adjustment unit 2 also includes at least one microprism 22, the microprism 22 is located between the collimation unit 4 and the linear diffuser 21, the microprism 22 has an inclined surface that is inclined relative to the optical axis direction of the outgoing light path of the collimation unit 4, and the inclined surface of the microprism 22 is used to deflect the collimated light and refract it toward the corresponding inclined smooth surface on the workpiece being measured.

[0041] The at least one microprism 22 is made of crystal material through a precision molding process. It can be a single microprism 22 or an array of multiple microprisms 22. Its function is to precisely deflect and refract light to adapt to the geometric characteristics of different areas on the surface of the workpiece being measured. The microprism 22 is precisely placed between the collimating unit 4 and the linear diffuser 21 to process and deflect the collimated light. The deflected light can then be further processed by the linear diffuser 21 or directly projected onto the workpiece being measured. The microprism 22 itself is designed with a preset tilted surface. This tilting setting allows the light incident on the microprism 22 to be deflected at a preset angle, thereby guiding the light to a specific tilted surface of the workpiece. The core function of the microprism 22 is to adjust the angle of the collimated light. Through its refraction principle, and based on its material and geometry, it changes the propagation direction of the light as it passes through, reflecting the light in a specific direction to ensure that the light can be accurately projected onto the smooth surfaces with specific tilt angles on the workpiece being measured, thereby achieving effective measurement of these areas.

[0042] The laser emitted by laser emitter 1 is first collimated by collimation unit 4 to form a parallel beam. This collimated beam then strikes the microprism 22 in beam adjustment unit 2. Due to the tilted arrangement of the microprism 22, the incident collimated light undergoes precise deflection and refraction as it passes through, guiding it to the corresponding tilted smooth surface on the workpiece being measured. Simultaneously, the diffuser 211 on the linear diffuser 21 in beam adjustment unit 2 is responsible for specifically diffusing the light to the local curvature variation areas on the tilted smooth surface. In this way, the microprism 22 and the linear diffuser 21 work together. The microprism 22 initially deflects the light, ensuring it is directed towards the tilted smooth surface at a uniform angle; while the linear diffuser further fine-tunes the diffusion to fit the local uneven areas on the tilted smooth surface. This allows the sensor to simultaneously and effectively project light onto areas with different geometric features on the workpiece being measured, including tilted smooth surfaces and curvature variation areas. Finally, the light is reflected by the workpiece and received by detection unit 3. This design ensures that light can accurately cover and effectively detect various areas on complex, smooth surfaces, significantly improving the comprehensiveness and accuracy of measurements.

[0043] In this embodiment, the laser emitter 1 uses a high-brightness semiconductor laser, which ensures that the emitted laser beam has good illumination intensity to a certain extent, so that it can still be effectively identified by the detection unit 3 after optical path loss. When the collimated light beam is incident on the inclined surface of the microprism 22, it will be deflected according to the law of refraction, thereby accurately refracting the light beam onto the preset inclined smooth surface on the workpiece being measured, so that each inclined smooth surface has a corresponding refracted light beam entering it. Subsequently, each inclined smooth surface reflects a portion of the light beam and it can be received by the same detection unit 3. At the same time, the beam adjustment unit 2 also includes a linear diffuser 21, the diffuser portion 211 of which can diffuse part of the light beam to the curvature change area of ​​the workpiece being measured. Finally, the light beam reflected back from the workpiece being measured is received by the detection unit 3 for subsequent displacement measurement and surface morphology reconstruction.

[0044] Through the above technical solution, at least one microprism 22 is introduced into the displacement measuring device for measuring complex smooth surfaces, and its inclined surface is tilted relative to the optical axis of the outgoing light path of the collimating unit 4. This improvement allows the collimated light to be precisely deflected and refracted, thereby effectively projecting it onto the smooth surfaces of the workpiece with specific tilt angles. Compared with the solution that relies solely on the linear diffuser 21 for light diffusion, this solution significantly enhances the sensor's measurement coverage of complex smooth surfaces, especially workpieces containing tilted smooth surfaces.

[0045] This application further proposes that the at least one microprism 22 includes a plurality of microprisms 22, which are arranged side by side and together constitute an integral optical surface.

[0046] In complex mirror measurements, multiple microprisms 22 can be used to independently process incident light from different regions or angles. "Parallel arrangement" refers to multiple microprisms 22 being closely arranged in space along a certain direction, adjacent to each other. In this embodiment, the multiple microprisms 22 are arranged side-by-side in a direction perpendicular to the optical path. This arrangement allows the incident light beam to be effectively split and guided to each microprism 22, thereby achieving parallel processing of the beam. Together, they form a unified optical surface, meaning that these parallel microprisms 22 functionally form a unified, continuous optical interface.

[0047] Reference Figure 3 In the scheme of this application, when collimated light is incident on this integral continuous optical surface, due to its integrated structural design, the relative positions and angles between the individual microprisms 22 are precisely fixed and maintained. The incident light is stably and precisely divided, and deflected and refracted by each microprism 22 onto the corresponding inclined smooth surface on the workpiece being measured. Through this synergistic effect, even if the workpiece being measured has multiple complex inclined smooth surfaces, it can ensure that each inclined surface is accurately and stably illuminated.

[0048] However, in practical applications, simply placing multiple microprisms 22 side-by-side or detachably snapping them together may lead to insufficient structural stability. For example, when subjected to external vibration, impact, or temperature changes, relative displacement may occur between individual microprisms 22, resulting in a decrease in optical surface precision, which in turn affects the accuracy of beam deflection and the final measurement accuracy. Furthermore, the tiny gaps between the microprisms 22 may also introduce optical discontinuities, affecting the quality of light transmission.

[0049] Therefore, this application further proposes that multiple microprisms 22 be fixed together by optical adhesive.

[0050] Specifically, optical adhesive is an adhesive with specific optical properties. Its main characteristics are high light transmittance and a refractive index that matches optical materials after curing, enabling it to provide structural connection and fixation without significantly affecting light transmission. For multiple microprisms 22, the bonding and fixation aims to ensure their precise and stable relative positions in space, preventing displacement due to mechanical stress, vibration, or environmental changes. Optical adhesive is applied to the contact surfaces of two adjacent microprisms 22 through methods such as dispensing or coating, and then cured by ultraviolet irradiation, thereby forming a strong connection. The solution in this application uses optical adhesive to bond and fix multiple microprisms 22, allowing the originally parallel microprisms 22 to form a structurally stable, optically consistent, integral optical surface. Furthermore, due to the excellent optical properties of the optical adhesive, the continuity and uniformity of light passing through the microprism array 22 are ensured, avoiding scattering, diffraction, or energy loss caused by gaps or uneven connections between the microprisms 22. This guarantees the accuracy of beam deflection and the quality of the light spot, laying the foundation for accurate imaging and displacement measurement in the subsequent detection unit 3.

[0051] However, in practical applications, the smooth surface of the workpiece being measured may contain multiple smooth surfaces with different tilt angles. If all microprisms 22 deflect the light at the same fixed angle, it is difficult to ensure that the light can be accurately incident on all surfaces with different tilt angles, which may affect the accuracy and applicability of the measurement.

[0052] Therefore, this application further proposes that the tilted surfaces of the plurality of microprisms 22 have the same or different tilt angles relative to the optical axis direction of the outgoing light path of the collimating unit 4, and the tilt angle of each microprism corresponds one-to-one with the tilt angle of each tilted smooth surface on the workpiece being tested, so that each microprism 22 refracts the corresponding light to the corresponding tilted smooth surface.

[0053] Specifically, the multiple microprisms 22 having the same or different tilt angles relative to the optical axis direction of the outgoing light path of the collimating unit 4 means that the optical deflection characteristics of each microprism 22 constituting the integral optical surface can be customized as needed. For example, each microprism 22 can be independently processed to have a specific apex angle and base angle to achieve a preset deflection effect; the tilt angle corresponds one-to-one with the tilt angle of each tilted smooth surface on the workpiece being tested. In actual operation, when designing or configuring these microprisms 22, the geometric information of each tilted smooth surface on the workpiece being tested, especially their tilt angles, is obtained in advance. Then, based on these known tilt angles, the deflection angle of each microprism 22 is accurately calculated and set to ensure that its outgoing light can be incident on the corresponding tilted smooth surface of the workpiece being tested at the optimal angle (e.g., perpendicular to the surface or at a specific incident angle, which is actually calculated based on the final position of the detection unit 3), so as to ensure that the light reflected from each tilted smooth surface is generally refracted onto the same detection unit 3. Through the precise tilt angle matching described above, the parallel beam emitted from the collimating unit 4 is decomposed into multiple independent beams with specific deflection directions when passing through the microprism 22. Each beam is handled by a specific microprism 22 and is precisely guided to a pre-specified smooth surface area with a specific tilt angle on the workpiece being measured. This refined optical path design ensures effective detection of each independent area on a complex smooth surface.

[0054] Through the above technical solution, this application can effectively solve the problem that light is difficult to accurately incident on all target areas when dealing with workpieces with multi-angle inclined smooth surfaces. Since the tilt angle of each microprism 22 corresponds one-to-one with the tilt angle of the corresponding inclined smooth surface on the workpiece being measured, it ensures that each inclined smooth surface can receive good light illumination, avoiding measurement errors or signal loss caused by improper light incident angle.

[0055] This application further proposes that the detection unit 3 includes an imaging module 31 and a photosensitive module 32 arranged sequentially on the optical path after reflection from the workpiece being tested. The imaging module 31 is a lens with a fixed focal length or a lens group with an adjustable focal length.

[0056] The imaging unit is an optical system used to capture and process light reflected from the workpiece under test to form an image that can be analyzed. This imaging unit can be composed of a series of optical elements, such as lenses, mirrors, and apertures, and its core function is to focus the reflected light and project it onto the photosensitive module 32. As one implementation, the imaging module 31 can use a fixed-focal-length lens, which is suitable for applications where the measurement distance or the range of surface features is relatively constant, offering a simple structure and low cost. Alternatively, the imaging module 31 can use an adjustable-focal-length lens group. This lens group can adjust the system's focal length by changing the relative positions of the lenses or the focal length of the lenses themselves, thereby adapting to different measurement distances, surface curvatures, or achieving different magnifications, offering high flexibility. The photosensitive module 32 is the component in the imaging unit that converts the optical image formed by the imaging module 31 into an electrical signal. The photosensitive module 32 is typically composed of semiconductor devices, and its function is to detect light intensity and position information and digitize this information for subsequent signal processing and analysis. The imaging module 31 and the photosensitive module 32 are arranged sequentially on the light path after being reflected by the workpiece under test. This means that the light reflected from the complex smooth surface of the workpiece under test enters the imaging module 31 for focusing, and then the focused light is projected onto the photosensitive module 32 for capture.

[0057] The aforementioned photosensitive module 32 is a high-sensitivity CMOS chip. A high-sensitivity CMOS chip is an image sensor with high quantum efficiency, low noise, and fast readout capability. Its main characteristic is its ability to effectively capture weak light signals and maintain good image quality in low-light environments. The solution in this application, by setting the photosensitive module 32 as a high-sensitivity CMOS chip, enables the entire displacement measurement device to more effectively convert light signals into electrical signals when receiving reflected light from the smooth surface of the workpiece. Specifically, when the light emitted by the laser emitter 1 is diffused by the beam adjustment unit 2 (including the linear diffuser 21) and irradiates the smooth surface of the workpiece, and is reflected back from the curvature change region, the reflected light enters the detection unit 3. In the detection unit 3, the imaging module 31 (whether a fixed-focus lens or an adjustable-focus lens group) focuses the reflected light onto the high-sensitivity CMOS chip. Thanks to its excellent photoelectric conversion efficiency and low noise characteristics, the high-sensitivity CMOS chip can capture clear, high signal-to-noise ratio image data even when faced with weak or scattered light signals reflected from complex smooth surfaces. This configuration ensures that the weak light signal reflected from the workpiece under test can be effectively detected and processed, thus providing reliable raw data for subsequent displacement calculations.

[0058] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A composite optical path type complex smooth surface global displacement measuring device, characterized in that, The system includes a laser emitter (1), a beam adjustment unit (2), and a detection unit (3), which are arranged sequentially along the optical path. The beam adjustment unit (2) includes a linear diffuser (21) with multiple diffuser portions (211) protruding from it. The diffuser portions (211) are used to diffuse light to the curvature change region on the smooth surface of the workpiece being tested. The detection unit (3) is located on the reflected light path after the light passes through the workpiece being tested. The system also includes a collimation unit (4), which is located between the laser emitter (1) and the beam adjustment unit (2) and is used to collimate the emitted light from the laser emitter (1) and guide it to the beam adjustment unit (2). The beam adjustment unit (2) also includes at least one microprism (22), which is located on the collimation unit. Between the element (4) and the linear diffuser (21), the microprism (22) has an inclined surface that is tilted relative to the optical axis of the collimating unit (4). The inclined surface of the microprism (22) is used to deflect the collimated light and refract it to the corresponding inclined smooth surface on the workpiece being tested. The at least one microprism (22) includes multiple microprisms (22), which are arranged side by side and together form an integral optical surface. The multiple microprisms (22) are fixed together by optical adhesive. The inclined surfaces of the multiple microprisms (22) have the same or different tilt angles relative to the optical axis of the collimating unit (4), and the tilt angle of each microprism (22) corresponds one-to-one with the tilt angle of each inclined smooth surface on the workpiece being tested, so that each microprism (22) refracts the corresponding light to the corresponding inclined smooth surface.

2. The composite optical path type complex smooth surface global displacement measuring device according to claim 1, characterized in that, The collimation unit (4) includes a cylindrical Fresnel lens (41) having a smooth surface and a sawtooth surface arranged opposite to each other. The smooth surface faces the laser emitter (1) to receive the laser, and the sawtooth surface faces the beam adjustment unit (2) to direct the collimated beam into the beam adjustment unit (2).

3. The composite optical path type complex smooth surface global displacement measuring device according to claim 2, characterized in that, The number of the cylindrical Fresnel lenses (41) is multiple, and the collimation unit (4) is composed of multiple cylindrical Fresnel lenses (41) arranged side by side in a direction perpendicular to the optical path.

4. The composite optical path type complex smooth surface global displacement measuring device according to claim 1, characterized in that, The detection unit (3) includes an imaging module (31) and a photosensitive module (32) arranged sequentially on the optical path after reflection from the workpiece being tested. The imaging module (31) is a fixed focal length lens or a lens group with adjustable focal length.

5. The composite optical path type complex smooth surface global displacement measuring device according to claim 4, characterized in that, The photosensitive module (32) is a CMOS chip.

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