Laser radar device and method for measuring surface topography of object to be measured

Abstract

The invention discloses a laser radar device and a method for measuring the surface topography of an object to be measured, and relates to the technical field of laser radars. The laser radar device comprises a reference interference module, a measurement interference module and a main control module. The reference interference module comprises a reference photoelectric conversion unit and a reference scanning unit; the measurement interference module comprises a measurement photoelectric conversion unit and a measurement scanning unit; the main control module is used for controlling the reference scanning unit and the measurement scanning unit to move synchronously; the reference photoelectric conversion unit is used for emitting a reference laser signal and generating a reference detection electric signal according to a reference detection optical signal fed back by the reference scanning unit; the measurement photoelectric conversion unit is used for emitting a measurement laser signal and generating a measurement detection electric signal according to a measurement detection optical signal fed back by the measurement scanning unit; the main control module is further used for determining the surface appearance of the to-be-detected object according to the reference detection electric signal and the measurement detection electric signal. According to the invention, the measurement area and precision of surface topography measurement are improved.

Description

Technical Field

[0001] This invention relates to the field of lidar technology, and more particularly to a lidar device and a method for measuring the surface morphology of an object under test. Background Technology

[0002] As a high-precision ranging and imaging technology, lidar technology is widely used in industrial manufacturing, aerospace and surface topography inspection, and occupies an important position in modern measurement technology due to its non-contact measurement and high-resolution characteristics.

[0003] In existing technologies, laser interferometers are typically used in lidar devices to measure the surface topography of objects. The laser interferometer determines the surface height variation of the object by detecting the optical phase difference between the local light and the signal light reflected back from the object. However, existing lidar devices require fixed positions for both the object and the laser interferometer, resulting in a small measurement area and making it difficult to meet the surface scanning requirements of large objects. Summary of the Invention

[0004] This invention provides a lidar device and a method for measuring the surface morphology of an object under test, which overcomes the size limitation of the object under test and improves the measurement area and measurement accuracy of the surface morphology of the object under test.

[0005] The first aspect of the present invention provides a lidar device for measuring the surface morphology of an object to be measured. The lidar device includes: at least one reference interferometry module, a measurement interferometry module, and a main control module.

[0006] The reference interferometry module includes a reference photoelectric conversion unit and a reference scanning unit;

[0007] The measurement interferometry module includes a measurement photoelectric conversion unit and a measurement scanning unit;

[0008] The main control module is used to control the synchronous movement of the reference scanning unit and the measurement scanning unit;

[0009] The reference photoelectric conversion unit is used to emit a reference laser signal to the reference scanning unit, and after receiving the reference detection optical signal fed back by the reference scanning unit, it generates a reference detection electrical signal based on the reference detection optical signal.

[0010] The measurement photoelectric conversion unit is used to emit a measurement laser signal to the measurement scanning unit, and after receiving the measurement detection optical signal fed back by the measurement scanning unit, it generates a measurement detection electrical signal based on the measurement detection optical signal.

[0011] The main control module is also used to determine the surface morphology of the object under test based on the reference detection electrical signal and the measurement detection electrical signal.

[0012] Optionally, the lidar device further includes: a displacement stage and at least one fixed base;

[0013] Both the reference scanning unit and the measurement scanning unit are mounted on the displacement stage;

[0014] The reference photoelectric conversion unit and the measurement photoelectric conversion unit are disposed on the fixed base;

[0015] The main control module is used to control the displacement stage to move the reference scanning unit and the measurement scanning unit.

[0016] Optionally, at least one of the reference interferometry modules includes a first reference interferometry module; the reference photoelectric conversion unit and the measurement photoelectric conversion unit of the first reference interferometry module are located on the same side of the displacement stage.

[0017] Optionally, the reference photoelectric conversion unit and the measurement photoelectric conversion unit of the first reference interferometer module are located on the same fixed base.

[0018] Optionally, at least one of the reference interferometry modules includes a second reference interferometry module; the reference photoelectric conversion unit of the second reference interferometry module and the measurement photoelectric conversion unit are located on opposite sides of the displacement stage.

[0019] Optionally, at least one of the reference interferometry modules includes a third reference interferometry module and a fourth reference interferometry module;

[0020] The reference photoelectric conversion unit and the measurement photoelectric conversion unit of the third reference interferometry module are located on the same side of the displacement stage or on opposite sides of the displacement stage, respectively.

[0021] The reference photoelectric conversion unit and the measurement photoelectric conversion unit of the fourth reference interferometry module are located on adjacent sides of the displacement stage, respectively.

[0022] Optionally, the reference photoelectric conversion unit includes a reference silicon photonic chip and a reference laser; the reference scanning unit includes a first reflector;

[0023] The reference laser is used to emit a reference laser signal to the reference silicon photonic chip;

[0024] The reference silicon photonics chip is used to generate the reference laser signal and the reference oscillation signal according to the reference laser signal, and to emit the reference laser signal to the first reflector so that the first reflector reflects the reference laser signal;

[0025] The reference silicon photonic chip is also used to receive the reference detection optical signal reflected by the first reflector, and to generate the reference detection electrical signal based on the reference oscillation signal and the reference detection optical signal.

[0026] Optionally, the reference photoelectric conversion unit further includes a light adjustment subunit;

[0027] The light adjustment subunit is located in the optical path between the reference silicon photonic chip and the first reflector; wherein, the light adjustment subunit includes a first collimating lens or a first focusing lens.

[0028] Optionally, the reference scanning unit further includes a second focusing lens;

[0029] The second focusing lens is located in the optical path between the light adjustment subunit and the first reflecting mirror.

[0030] Optionally, the measurement photoelectric conversion unit includes a measurement silicon photonic chip and a measurement laser; the measurement scanning unit includes a second reflector;

[0031] The measurement laser is used to emit measurement laser signals to the measurement silicon photonic chip;

[0032] The measurement silicon photonics chip is used to generate the measurement laser signal and the measurement oscillation signal based on the measurement laser signal, and to emit the measurement laser signal to the second reflector so that the second reflector reflects the measurement laser signal;

[0033] The measurement silicon photonic chip is also used to receive the measurement detection optical signal reflected by the second reflector, and to generate the measurement detection electrical signal based on the measurement oscillation signal and the measurement detection optical signal.

[0034] Optionally, the measurement photoelectric conversion unit further includes a third focusing lens;

[0035] The third focusing lens is located in the optical path between the measuring silicon photonic chip and the second reflecting mirror.

[0036] Optionally, the lidar device further includes: an image acquisition module;

[0037] The image acquisition module is connected to the main control module. The image acquisition module is used to acquire surface image information of the object under test and provide the surface image information to the main control module.

[0038] The main control module is also used to determine the effective scanning area based on the surface image information, and to control the reference scanning unit and the measurement scanning unit to move synchronously based on the effective scanning area.

[0039] Optionally, the lidar device further includes: at least one reference signal modulation module corresponding one-to-one with at least one of the reference interferometry modules; the reference signal modulation module is correspondingly disposed in the optical path between the reference photoelectric conversion unit and the reference scanning unit; and / or,

[0040] A measurement signal modulation module is disposed in the optical path between the measurement photoelectric conversion unit and the measurement scanning unit.

[0041] A second aspect of the present invention provides a method for measuring the surface topography of an object under test based on a lidar device as described above, the surface topography measurement method comprising:

[0042] After controlling the movement of the reference scanning unit and the measurement scanning unit, the main control module acquires the reference detection electrical signal provided by the reference photoelectric conversion unit and the measurement detection electrical signal provided by the measurement photoelectric conversion unit, respectively.

[0043] The main control module determines the moving distance of the measurement scanning unit based on the reference detection electrical signal;

[0044] The main control module determines the surface morphology information of the object under test based on the reference detection electrical signal and the measurement detection electrical signal;

[0045] The main control module determines the surface morphology of the object under test based on the moving distance and the surface morphology information.

[0046] The technical solution of this invention, by setting at least one reference interferometry module, a measurement interferometry module, and a main control module in a lidar device, and by setting a reference photoelectric conversion unit and a reference scanning unit in the reference interferometry module, and a measurement photoelectric conversion unit and a measurement scanning unit in the measurement interferometry module, enables the main control module to control the synchronous movement of the reference scanning unit and the measurement scanning unit. This allows the reference photoelectric conversion unit to emit a reference laser signal to the reference scanning unit, and upon receiving a reference detection light signal from the reference scanning unit, to generate a reference detection electrical signal based on the reference detection light signal. This allows the main control module to determine the distance moved by the reference scanning unit and the measurement scanning unit using the reference detection electrical signal. Simultaneously, the measurement photoelectric conversion unit can emit a measurement laser signal to the measurement scanning unit, and upon receiving a measurement detection light signal from the measurement scanning unit, to generate a measurement detection electrical signal based on the measurement detection light signal. Since changes in the height of the object under test surface and the moving distance of the measurement scanning unit both cause changes in the optical path length of the measurement detection light signal, the main control module can also calibrate the measurement detection electrical signal using the reference detection electrical signal to accurately determine the height change of the object under test surface. The main control module can also determine the surface morphology of the object under test based on the moving distance and the change in surface height at the corresponding moving distance, thus improving the measurement accuracy of the surface morphology measurement. Furthermore, by controlling the movement of the measurement scanning unit, the measurement area of ​​the object's surface morphology is increased, enabling it to meet the surface scanning requirements of large-sized objects.

[0047] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 This is a schematic diagram of the structure of a lidar device provided in an embodiment of the present invention;

[0050] Figure 2 This is a schematic diagram of another lidar device provided in an embodiment of the present invention;

[0051] Figure 3 This is a schematic diagram of another lidar device provided in an embodiment of the present invention;

[0052] Figure 4 This is a schematic diagram of another lidar device provided in an embodiment of the present invention;

[0053] Figure 5 This is a schematic diagram of another lidar device provided in an embodiment of the present invention;

[0054] Figure 6 This is a schematic flowchart of a method for measuring the surface morphology of an object to be tested, provided in an embodiment of the present invention. Detailed Implementation

[0055] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0056] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0057] Figure 1 This is a schematic diagram of a lidar device provided in an embodiment of the present invention. The lidar device is used to measure the surface morphology of an object to be measured. Figure 1As shown, the lidar device includes: at least one reference interferometry module 1, a measurement interferometry module 2, and a main control module 3; the reference interferometry module 1 includes a reference photoelectric conversion unit 11 and a reference scanning unit 12; the measurement interferometry module 2 includes a measurement photoelectric conversion unit 21 and a measurement scanning unit 22; the main control module 3 is used to control the synchronous movement of the reference scanning unit 12 and the measurement scanning unit 22; the reference photoelectric conversion unit 11 is used to emit a reference laser signal to the reference scanning unit 12, and after receiving the reference detection light signal fed back by the reference scanning unit 12, it generates a reference detection electrical signal based on the reference detection light signal; the measurement photoelectric conversion unit 21 is used to emit a measurement laser signal to the measurement scanning unit 22, and after receiving the measurement detection light signal fed back by the measurement scanning unit 22, it generates a measurement detection electrical signal based on the measurement detection light signal; the main control module 3 is also used to determine the surface morphology of the object to be measured based on the reference detection electrical signal and the measurement detection electrical signal.

[0058] Specifically, the reference interferometry module 1 and the measurement interferometry module 2 are used to generate laser signals and process the detection optical signals to measure the surface morphology of the object under test 01. The main control module 3 may include a microprocessor, such as a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The main control module 3 is specifically used to determine the surface morphology of the object under test 01 based on the detection electrical signals fed back from the reference interferometry module 1 and the measurement interferometry module 2. Specifically, the reference interferometry module 1 includes a reference photoelectric conversion unit 11 and a reference scanning unit 12, and the measurement interferometry module 2 includes a measurement photoelectric conversion unit 21 and a measurement scanning unit 22, so that the main control module 3 can control the synchronous movement of the reference scanning unit 12 and the measurement scanning unit 22, thereby enabling a comprehensive scan of the large-sized object under test 01 through the measurement interferometry module 2. Meanwhile, the main control module 01 can calibrate the measurement detection electrical signal fed back by the measurement interference module 2 based on the reference detection electrical signal fed back by the reference interference module 1, thereby realizing accurate measurement of the surface morphology of the object to be measured 01.

[0059] For example, the reference photoelectric conversion unit 11 may include a laser and a silicon photonics chip. The laser generates a stable laser signal and emits it to the silicon photonics chip. The silicon photonics chip may have a beam-splitting unit that splits the laser signal into a reference laser signal and a reference oscillation signal. The silicon photonics chip emits the reference laser signal to the reference scanning unit 12, and the reference oscillation signal is used for subsequent interference. The reference scanning unit 12 may include a reflector. The reference scanning unit 12 emits the reference laser signal provided by the reference photoelectric conversion unit 11 to the reflector and acquires the reference detection light signal formed after the reference laser signal is reflected by the reflector. The displacement of the reflector causes a change in the optical path length of the reference detection light signal. After acquiring the reference detection light signal, the reference scanning unit 12 can also feed the reference detection light signal back to the reference photoelectric conversion unit 11, so that the silicon photonics chip in the reference photoelectric conversion unit 11 can interfere with the reference oscillation signal and the reference detection light signal to generate an interference light signal, and can convert the intensity of the interference light signal into a reference detection electrical signal and provide it to the main control module 3. It is understandable that the intensity change of the interference light signal is related to the phase difference between the reference oscillation signal and the reference detection light signal, and the phase difference between the reference oscillation signal and the reference detection light signal is related to the change in the optical path length of the reference detection light signal. That is, the phase difference between the reference oscillation signal and the reference detection light signal is related to the displacement of the reflector. Therefore, after the main control module 3 acquires the reference detection electrical signal provided by the reference photoelectric conversion unit 11, it can sample the voltage amplitude of the reference detection electrical signal through the analog-to-digital converter. This allows it to determine the distance that the reference scanning unit 12 and the measurement scanning unit 22 move synchronously based on the voltage amplitude of the reference detection electrical signal, thus laying the foundation for subsequent calibration of the measurement detection electrical signal fed back by the measurement interferometry module 2 based on the reference detection electrical signal fed back by the reference interferometry module 1.

[0060] The measurement photoelectric conversion unit 21 may include a laser and a silicon photonics chip. The laser generates a stable laser signal and emits it to the silicon photonics chip. The silicon photonics chip may have a beam-splitting unit that splits the laser signal into a measurement laser signal and a measurement oscillation signal. The silicon photonics chip emits the measurement laser signal to the measurement scanning unit 22, and the measurement oscillation signal is used for subsequent interference. The measurement scanning unit 22 emits the measurement laser signal provided by the measurement photoelectric conversion unit 21 to the object under test 01 and acquires the measurement detection light signal formed after the measurement laser signal is reflected by the object under test 01. Changes in the surface height of the object under test 01 will cause changes in the optical path length of the measurement detection light signal. After acquiring the measurement detection light signal, the measurement scanning unit 22 can also feed the measurement detection light signal back to the measurement photoelectric conversion unit 21, so that the silicon photonics chip in the measurement photoelectric conversion unit 21 can interfere with the measurement oscillation signal and the measurement detection light signal to generate an interference light signal, and can convert the intensity of the interference light signal into a measurement detection electrical signal and provide it to the main control module 3. It is understandable that the intensity change of the interference light signal is related to the phase difference between the measurement oscillation signal and the measurement detection light signal, and the phase difference between the measurement oscillation signal and the measurement detection light signal is related to the height change of the surface of the object under test 01. Therefore, after the main control module 3 acquires the measurement detection electrical signal provided by the measurement photoelectric conversion unit 21, it can sample the voltage amplitude of the measurement detection electrical signal through the analog-to-digital converter, so as to determine the height change of the surface of the object under test 01 through the voltage amplitude of the measurement detection electrical signal, thereby laying the foundation for the subsequent determination of the surface morphology of the object under test 01.

[0061] It is also understandable that the moving distance of the measurement scanning unit 22 will cause a change in the optical path length of the measurement detection optical signal. Therefore, it is necessary to calibrate the measurement detection electrical signal fed back by the measurement interferometer module 2 using the reference detection electrical signal fed back by the reference interferometer module 1. For example, the main control module 3 can calculate the difference between the displacement calculated based on the measurement detection electrical signal and the displacement calculated based on the reference detection electrical signal to eliminate the interference of the moving distance of the measurement scanning unit 22 on the measurement detection optical signal, thereby accurately determining the height change of the surface of the object under test 01 based on the difference between the displacements. After the main control module 3 determines the height change of the surface of the object under test 01, it can use the displacement determined based on the reference detection electrical signal as the X-axis to represent the physical position of the scanning path, and use the calibrated height change of the surface of the object under test 01 as the Y-axis to represent the height change of the surface morphology at the corresponding physical position of the scanning path, thereby generating a surface morphology distribution map of the object under test 01 to fully reflect the surface morphology of the object under test 01.

[0062] By controlling the synchronous movement of the reference scanning unit 12 and the measurement scanning unit 22, the measurement laser signal can completely scan the surface of the object under test 01. This overcomes the limitation of the measurement area imposed by the fixed laser interferometer in traditional lidar devices, increasing the measurement area for the surface morphology measurement of the object under test, thus meeting the surface scanning requirements of large-sized objects under test 01. Simultaneously, through the coordinated action of the reference interferometry module 1 and the measurement interferometry module 2, the interference of the movement distance of the measurement scanning unit 22 on the measurement detection light signal is eliminated. This allows for the accurate determination of the height changes on the surface of the object under test 01, improving the measurement accuracy of the surface morphology measurement and ensuring the reliability and consistency of the surface morphology data of the object under test 01.

[0063] In this embodiment, by incorporating at least one reference interferometry module, a measurement interferometry module, and a main control module into the lidar device, and by setting up a reference photoelectric conversion unit and a reference scanning unit in the reference interferometry module, and a measurement photoelectric conversion unit and a measurement scanning unit in the measurement interferometry module, the main control module can control the synchronous movement of the reference scanning unit and the measurement scanning unit. This allows the reference photoelectric conversion unit to emit a reference laser signal to the reference scanning unit and, upon receiving a reference detection light signal from the reference scanning unit, to generate a reference detection electrical signal based on the reference detection light signal. The main control module can then determine the distance moved by the reference scanning unit and the measurement scanning unit using the reference detection electrical signal. Simultaneously, the measurement photoelectric conversion unit can emit a measurement laser signal to the measurement scanning unit and, upon receiving a measurement detection light signal from the measurement scanning unit, to generate a measurement detection electrical signal based on the measurement detection light signal. Since changes in the height of the object's surface and the movement distance of the measurement scanning unit both cause changes in the optical path length of the measurement detection light signal, the main control module can also calibrate the measurement detection electrical signal using the reference detection electrical signal to accurately determine the height change of the object's surface. The main control module can also determine the surface morphology of the object under test based on the moving distance and the change in surface height at the corresponding moving distance, thus improving the measurement accuracy of the surface morphology measurement. Furthermore, by controlling the movement of the measurement scanning unit, the measurement area of ​​the object's surface morphology is increased, enabling it to meet the surface scanning requirements of large-sized objects.

[0064] Optional, Figure 2 This is a schematic diagram of another lidar device provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the lidar device also includes: a displacement stage 4 and at least one fixed base 5; a reference scanning unit 12 and a measurement scanning unit 22 are both disposed on the displacement stage 4; a reference photoelectric conversion unit 11 and a measurement photoelectric conversion unit 21 are disposed on the fixed base 5; and a main control module 3 is used to control the displacement stage 4 to move the reference scanning unit 12 and the measurement scanning unit 22.

[0065] The displacement stage 4 serves as a moving platform, specifically supporting the reference scanning unit 12 and the measurement scanning unit 22. When the main control module 3 controls the displacement stage 4 to move the reference scanning unit 12 and the measurement scanning unit 22, the measurement laser signal provided by the measurement scanning unit 22 will also move. The object under test 01 can be positioned on the displacement stage 4 near the measurement scanning unit 22, allowing the scanning range of the measurement laser signal to cover a larger area of ​​the surface of the object under test 01. This overcomes the limitation of the measurement area imposed by the fixed laser interferometer in traditional lidar devices, increasing the measurement area for measuring the surface morphology of the object under test. Simultaneously, both the reference scanning unit 12 and the measurement scanning unit 22 are mounted on the displacement stage 4, ensuring that their displacements are consistent. This facilitates the calibration of the measurement detection electrical signal fed back by the measurement interferometer module 2 using the reference detection electrical signal fed back by the reference interferometer module 1.

[0066] The fixed base 5 serves as a stable installation platform, specifically used to support the reference photoelectric conversion unit 11 and the measurement photoelectric conversion unit 21. This ensures that the positions of the reference photoelectric conversion unit 11 and the second laser generating unit 12 are fixed, enabling the reference photoelectric conversion unit 11 to stably provide a reference laser signal to the reference scanning unit 12 and to stably receive the reference detection light signal fed back by the reference scanning unit 12. The measurement photoelectric conversion unit 21 can stably provide a measurement laser signal to the measurement scanning unit 22 and can stably receive the measurement detection light signal fed back by the measurement scanning unit 22, thus avoiding measurement errors caused by vibration or movement.

[0067] Optional, continue to refer to Figure 2 At least one reference interferometer module 1 includes a first reference interferometer module 101; the reference photoelectric conversion unit 11 and the measurement photoelectric conversion unit 21 of the first reference interferometer module 101 are located on the same side of the displacement stage 4.

[0068] Specifically, the reference photoelectric conversion unit 11 and the measurement photoelectric conversion unit 21 of the first reference interferometry module 101 are located on the same side of the displacement stage 4, so that when the main control module 3 controls the displacement stage 4 to move the reference scanning unit 12 and the measurement scanning unit 22, the reference interferometry module 1 and the measurement interferometry module 2 can independently perform laser signal transmission and data acquisition, which optimizes the optical path space utilization, reduces beam cross interference, and improves the measurement accuracy of the surface morphology measurement of the object under test.

[0069] Optional, continue to refer to Figure 2 The reference photoelectric conversion unit 11 and the measurement photoelectric conversion unit 21 of the first reference interference module 101 are located on the same fixed base 5.

[0070] Specifically, when the reference photoelectric conversion unit 11 and the measurement photoelectric conversion unit 21 of the first reference interferometry module 101 are located on the same side of the displacement stage 4, the reference photoelectric conversion unit 11 and the measurement photoelectric conversion unit 21 of the first reference interferometry module 101 can be located on the same fixed base 5. This simplifies the structure of the lidar device, saves the manufacturing cost of the lidar device, and ensures that the photoelectric conversion unit 11 can stably provide the reference laser signal and stably receive the reference detection light signal, and the measurement photoelectric conversion unit 21 can stably provide the measurement laser signal and stably receive the measurement detection light signal, thereby improving the efficiency and accuracy of the surface morphology measurement of the object under test.

[0071] Optional, Figure 3 This is a schematic diagram of another lidar device provided in an embodiment of the present invention, as shown below. Figure 3 As shown, at least one reference interferometry module 1 includes a second reference interferometry module 102; the reference photoelectric conversion unit 11 and the measurement photoelectric conversion unit 21 of the second reference interferometry module 102 are located on opposite sides of the displacement stage 4.

[0072] Specifically, the reference photoelectric conversion unit 11 and the measurement photoelectric conversion unit 21 of the second reference interferometry module 102 are located on opposite sides of the displacement stage 4, that is, the reference photoelectric conversion unit 11 and the measurement photoelectric conversion unit 21 of the second reference interferometry module 102 are respectively mounted on two fixed bases 5 located on opposite sides of the displacement stage 4. It can be understood that by setting the reference photoelectric conversion unit 11 and the measurement photoelectric conversion unit 21 on opposite sides of the displacement stage 4, compared with the technical solution of setting the reference photoelectric conversion unit 11 and the measurement photoelectric conversion unit 21 on the same fixed base 5, the width requirement of the lidar device along the arrangement direction of the photoelectric conversion unit 11 and the measurement photoelectric conversion unit 21 is reduced, thereby saving space and improving the flexibility and efficiency of surface topography measurement of the object under test.

[0073] Optional, Figure 4 This is a schematic diagram of another lidar device provided in an embodiment of the present invention, as shown below. Figure 4 As shown, at least one reference interferometry module 1 includes a third reference interferometry module 103 and a fourth reference interferometry module 104; the reference photoelectric conversion unit 11 and the measurement photoelectric conversion unit 21 of the third reference interferometry module 103 are located on the same side of the displacement stage 4 or on opposite sides of the displacement stage 4 respectively; the reference photoelectric conversion unit 11 and the measurement photoelectric conversion unit 21 of the fourth reference interferometry module 104 are located on adjacent sides of the displacement stage 4 respectively.

[0074] Specifically, the reference interferometry module 1 may include a third reference interferometry module 103 and a fourth reference interferometry module 104. The reference photoelectric conversion unit 11 and the measurement photoelectric conversion unit 21 of the third reference interferometry module 103 are located on the same side of the displacement stage 4 or on opposite sides of the displacement stage 4. The reference photoelectric conversion unit 11 and the measurement photoelectric conversion unit 21 of the fourth reference interferometry module 104 are located on adjacent sides of the displacement stage 4, thereby enabling two-dimensional scanning of the object 01 to be measured. Unless otherwise specified, the technical solution of the present invention will be exemplarily described using the example of the reference photoelectric conversion unit 11 and the measurement photoelectric conversion unit 21 of the third reference interferometry module 103 being located on the same side of the displacement stage 4. When the main control module 2 controls the displacement stage 4 to move vertically, the moving distance of the measurement scanning unit 22 can be measured by the third reference interference module 103, so that the control module 2 can determine the surface morphology of the object under test 01 in the vertical direction based on the reference measurement electrical signal fed back by the third reference interference module 103 and the measurement detection electrical signal fed back by the measurement interference module 2; when the main control module 2 controls the displacement stage 4 to move horizontally, the moving distance of the measurement scanning unit 22 can be measured by the fourth reference interference module 104, so that the control module 2 can determine the surface morphology of the object under test 01 in the horizontal direction based on the reference measurement electrical signal fed back by the fourth reference interference module 104 and the measurement detection electrical signal fed back by the measurement interference module 2.

[0075] Two-dimensional scanning of the object under test 01 is achieved through the third reference interferometry module 103 and the fourth reference interferometry module 104, which can meet the surface scanning requirements of complex curved surfaces or large-sized objects under test 01, and improve the measurement area and measurement accuracy of the surface morphology measurement of the object under test.

[0076] Optional, continue to refer to Figure 2 The reference photoelectric conversion unit 11 includes a reference silicon photonic chip 111 and a reference laser 112; the reference scanning unit 12 includes a first reflector 121; the reference laser 112 is used to emit a first laser signal to the reference silicon photonic chip 111; the reference silicon photonic chip 111 is used to generate a reference laser signal and a reference oscillation signal according to the first laser signal, and emit the reference laser signal to the first reflector 121 so that the first reflector 121 reflects the reference laser signal; the reference silicon photonic chip 111 is also used to receive the reference detection light signal reflected by the first reflector 121, and generate a reference detection electrical signal according to the reference oscillation signal and the reference detection light signal.

[0077] Specifically, the reference photoelectric conversion unit 11 includes a reference silicon photonics chip 111 and a reference laser 112. The reference scanning unit 12 includes a first reflector 121. The reference laser 112 generates a stable first laser signal and emits it to the reference silicon photonics chip 111. The reference silicon photonics chip 111 internally includes a beam splitting unit and a photodetector. The beam splitting unit splits the first laser signal into a reference laser signal and a reference oscillation signal. The reference silicon photonics chip 111 emits the reference laser signal to the first reflector 121 and the reference oscillation signal to the photodetector for subsequent interference. The first reflector 121 reflects the reference laser signal, and the reference silicon photonics chip 111 also acquires the reference detection light signal reflected by the first reflector 121. Changes in the displacement of the first reflector 121 cause changes in the optical path length of the reference detection light signal. After the reference silicon photonics chip 111 acquires the reference detection light signal, the photodetector interferes with the reference oscillation signal and the reference detection light signal to generate an interference light signal. The photodetector converts the intensity of the interference light signal into a reference detection electrical signal and provides it to the main control module 3. This lays the foundation for subsequent calibration of the measurement detection electrical signal fed back by the measurement interferometer module 2 based on the reference detection electrical signal fed back by the reference interferometer module 1.

[0078] Optional, continue to refer to Figure 2 The reference photoelectric conversion unit 11 further includes a light adjustment subunit 105; the light adjustment subunit 105 is located in the optical path between the reference silicon photonic chip 111 and the first reflector 121; wherein, the light adjustment subunit 105 includes a first collimating lens 113; or, as Figure 5 As shown, the light adjustment subunit 105 includes a first focusing lens 114.

[0079] Specifically, the reference photoelectric conversion unit 11 further includes a light adjustment subunit 105. The light adjustment subunit 105 is located in the optical path between the reference silicon photonics chip 111 and the first reflector 121, enabling adjustment of the light of the reference laser signal and the reference detection light signal via the fiber optic adjustment subunit 105. In an exemplary embodiment, the light adjustment subunit 105 may include a first collimating lens 113. The reference silicon photonics chip 111 can emit the reference laser signal to the first collimating lens 113, and the first collimating lens 113 can collimate the reference laser signal into parallel light. Optionally, continuing with the reference... Figure 2The reference scanning unit 12 also includes a second focusing mirror 122; the second focusing mirror 122 is located in the optical path between the light adjustment subunit 105 and the first reflecting mirror 121. Therefore, the first collimating mirror 113 can transmit parallel light to the second focusing mirror 122. The second focusing mirror 122 can focus the reference laser signal onto the first reflecting mirror 121 and can acquire the reference detection light signal formed after the reference laser signal is reflected by the first reflecting mirror 121. After acquiring the reference detection light signal, the second focusing mirror 122 can also feed the reference detection light signal back to the first collimating mirror 113. The first collimating mirror 113 can also feed the reference detection light signal back to the photodetector of the reference silicon photonic chip 111. In addition, the second focusing mirror 122 and the first reflecting mirror 121 can also be implemented in the form of a right-angled triangular pyramidal reflecting mirror or a pyramidal reflecting mirror.

[0080] In another exemplary embodiment, the light adjustment subunit 105 may include a first focusing lens 114. The reference silicon photonics chip 111 can emit a reference laser signal to the first focusing lens 114. The first focusing lens 114 can focus the reference laser signal onto the first reflecting mirror 121 and acquire the reference detection light signal formed after the reference laser signal is reflected by the first reflecting mirror 121. After acquiring the reference detection light signal, the first focusing lens 114 can also feed the reference detection light signal back to the photodetector of the reference silicon photonics chip 111. It is understood that in the technical solution of setting a first collimating lens 113 in the reference photoelectric conversion unit 11 and setting a second focusing lens 122 in the reference scanning unit 12, the first collimating lens 113 and the second focusing lens 122 need to be precisely aligned, and a specific focusing distance needs to be maintained between the second focusing lens 122 and the first reflecting mirror 121. By setting a first focusing lens 114 in the reference photoelectric conversion unit 11 to replace the first collimating lens 113 and the second focusing lens 122, the number of optical components in the lidar device is reduced, improving the convenience of installation and maintenance. Simultaneously, by adjusting the focal length or position of the first focusing lens 114, it can be adapted to the first reflecting mirror 121 at different distances, eliminating the need for strict limitations on the distance between the first focusing lens 114 and the first reflecting mirror 121, thus enhancing the flexibility of surface topography measurement of the object under test.

[0081] Optional, continue to refer to Figure 2The measurement photoelectric conversion unit 21 includes a measurement silicon photonic chip 211 and a measurement laser 212; the measurement scanning unit 22 includes a second reflector 221; the measurement laser 212 is used to emit a second laser signal to the measurement silicon photonic chip 211; the measurement silicon photonic chip 211 is used to generate a measurement laser signal and a measurement oscillation signal according to the second laser signal, and emit the measurement laser signal to the second reflector 221 so that the second reflector 221 reflects the measurement laser signal; the measurement silicon photonic chip 211 is also used to receive the measurement detection light signal reflected by the second reflector 221, and generate a measurement detection electrical signal according to the measurement oscillation signal and the measurement detection light signal.

[0082] Specifically, the measurement photoelectric conversion unit 21 includes a measurement silicon photonic chip 211 and a measurement laser 212. The measurement laser 212 generates a stable second laser signal and emits it to the measurement silicon photonic chip 211. The measurement silicon photonic chip 211 internally houses a beam-splitting unit and a photodetector. The beam-splitting unit splits the second laser signal into a measurement laser signal and a measurement oscillation signal, and emits the measurement laser signal to the second reflector 221 and the measurement oscillation signal to the photodetector for subsequent interferometry. Optionally, refer to [reference needed]. Figure 2 The photoelectric conversion unit 21 also includes a third focusing mirror 213; the third focusing mirror 213 is located in the optical path between the measuring silicon photonic chip 211 and the second reflecting mirror 221. Therefore, the beam splitting unit can transmit the measuring laser signal to the third focusing mirror 213, and the third focusing mirror 213 can transmit the measuring laser signal to the second reflecting mirror 221, so that the second reflecting mirror 221 can transmit the second laser signal to the object under test 01 and acquire the measuring detection light signal formed after the measuring laser signal is reflected by the object under test 01. Changes in the surface height of the object under test 01 will cause changes in the optical path length of the measuring detection light signal. For example, the second reflecting mirror 221 may specifically include a reflecting mirror or a right-angled triangular prism set at a 45° angle to the third focusing mirror 213.

[0083] After the second reflecting mirror 221 acquires the measurement and detection light signal, it can also feed the measurement and detection light signal back to the third focusing mirror 213. The third focusing mirror 213 can also feed the measurement and detection light signal back to the photodetector of the measurement silicon photonic chip 211, so that the photodetector can also interfere with the measurement oscillation signal and the measurement and detection light signal to generate an interference light signal, and can convert the light intensity of the interference light signal into a measurement and detection electrical signal and provide it to the main control module 3, so that the height change of the surface of the object under test 01 can be determined by the voltage amplitude of the measurement and detection electrical signal, thus laying the foundation for the subsequent determination of the surface morphology of the object under test 01.

[0084] Optional, continue to refer to Figure 2The lidar device also includes: an image acquisition module 6; the image acquisition module 6 is connected to the main control module 3, the image acquisition module 6 is used to acquire surface image information of the object to be measured 01, and provide the surface image information to the main control module 3; the main control module 3 is also used to determine the effective scanning area based on the surface image information, and control the reference scanning unit 12 and the measurement scanning unit 22 to move synchronously based on the effective scanning area.

[0085] Specifically, the image acquisition module 06 is used to acquire surface image information of the object under test 01. For example, the image acquisition module 06 may include a camera. Specifically, after acquiring the surface image information of the object under test 01, the image acquisition module 06 can also provide the surface image information to the main control module 3 via a data interface, such as a USB interface or Ethernet. After receiving the surface image information, the main control module 3 can also identify the effective scanning area of ​​the surface of the object under test 01 through an image processing algorithm, excluding non-critical parts of the surface of the object under test 01, such as edge cracks or non-measurement areas. The effective area of ​​the surface of the object under test 01 can be manually set by the operator or automatically selected by the main control module 3 to adapt to diverse needs of surface morphology measurement. The main control module 3 can also control the reference scanning unit 12 and the measurement scanning unit 22 to move synchronously according to the size and position of the effective scanning area, so that the measurement laser signal of the measurement scanning unit 22 only scans the effective scanning area. The image acquisition module 06 enables the measurement scanning unit 22 to focus on the key areas of the surface of the object to be measured 01, avoiding the waste of resources caused by scanning invalid areas of the surface of the object to be measured 01, and improving the efficiency and flexibility of the surface morphology measurement of the object to be measured.

[0086] Optional, continue to refer to Figure 2 The lidar device further includes: at least one reference signal modulation module 7 corresponding to at least one reference interference module 1; the reference signal modulation module 7 is disposed in the optical path between the reference photoelectric conversion unit 11 and the reference scanning unit 12; and / or, a measurement signal modulation module 8 is disposed in the optical path between the measurement photoelectric conversion unit 21 and the measurement scanning unit 22.

[0087] Specifically, the reference signal modulation module 7 is configured in a one-to-one correspondence with the reference interference module 1, and the reference signal modulation module 7 is disposed in the optical path between the reference photoelectric conversion unit 11 and the reference scanning unit 12, so that the reference signal modulation module 7 can enhance the signal strength of the reference detection optical signal fed back from the reference scanning unit 12 to the reference photoelectric conversion unit 11. The measurement signal modulation module 8 is disposed in the optical path between the measurement photoelectric conversion unit 21 and the measurement scanning unit 22, so that the measurement signal modulation module 8 can enhance the signal strength of the measurement detection optical signal fed back from the measurement scanning unit 22 to the measurement photoelectric conversion unit 21. For example, the reference signal modulation module 7 and the measurement signal modulation module 8 may include at least one of optical elements such as a quarter-wave plate, a rotator, or a polarizer. The quarter-wave plate can reduce reflection loss and improve the signal strength of the reference detection optical signal and the measurement detection optical signal by adjusting the polarization state of the reference detection optical signal and the measurement detection optical signal. The rotator can optimize the polarization matching of the reference detection optical signal and the measurement detection optical signal to enhance the overlap efficiency between the reference detection optical signal and the reference oscillation signal, as well as the overlap efficiency between the measurement detection optical signal and the measurement oscillation signal. Polarizers can filter out non-target light, such as scattered light or ambient light, from the reference detection optical signal and the measurement detection optical signal to improve the signal-to-noise ratio of the reference detection optical signal and the measurement detection optical signal.

[0088] When the reference detection optical signal modulated by the reference signal modulation module 7 and the measurement detection optical signal modulated by the measurement signal modulation module 8 interfere with the reference oscillation signal and the measurement oscillation signal respectively, the coherence is stronger, and the interference fringes or light intensity changes are more obvious. This improves the signal quality of the reference detection electrical signal and the measurement detection electrical signal received by the main control module 3, facilitates the accurate extraction of phase difference, and improves the efficiency and accuracy of the surface morphology measurement of the object under test.

[0089] Based on the same inventive concept, embodiments of the present invention also provide a method for measuring the surface topography of an object under test, which is implemented based on the lidar device described in the above embodiments. Correspondingly, as... Figure 6 As shown, the surface topography measurement method for the object under test may include:

[0090] S101. After controlling the movement of the reference scanning unit and the measurement scanning unit, the main control module acquires the reference detection electrical signal provided by the reference photoelectric conversion unit and the measurement detection electrical signal provided by the measurement photoelectric conversion unit, respectively.

[0091] Specifically, after the main control module 3 controls the movement of the reference scanning unit 12 and the measurement scanning unit 22, the reference silicon photonic chip 111 in the reference photoelectric conversion unit 11 can interfere with the reference oscillation signal and the reference detection light signal to generate an interference light signal, and can convert the light intensity of the interference light signal into a reference detection electrical signal and provide it to the main control module 3; the measurement silicon photonic chip 211 in the measurement photoelectric conversion unit 21 can interfere with the measurement oscillation signal and the measurement detection light signal to generate an interference light signal, and can convert the light intensity of the interference light signal into a measurement detection electrical signal and provide it to the main control module 3.

[0092] S102. The main control module determines the moving distance of the measurement scanning unit based on the reference detection electrical signal.

[0093] Specifically, after the main control module 3 obtains the reference detection electrical signal provided by the reference photoelectric conversion unit 11, it can sample the voltage amplitude of the reference detection electrical signal through an analog-to-digital converter so as to determine the distance moved by the reference scanning unit 12 and the measurement scanning unit 22 through the voltage amplitude of the reference detection electrical signal.

[0094] S103. The main control module determines the surface morphology information of the object under test based on the reference detection electrical signal and the measurement detection electrical signal.

[0095] Specifically, after the main control module 3 obtains the reference detection electrical signal provided by the reference photoelectric conversion unit 11 and the measurement detection electrical signal provided by the measurement photoelectric conversion unit 21, it can calibrate the measurement detection electrical signal through the reference detection electrical signal to eliminate the interference of the moving distance of the measurement scanning unit 22 on the measurement detection optical signal, thereby accurately determining the height change of the surface of the object under test 01, that is, the surface morphology information of the object under test 01.

[0096] S104. The main control module determines the surface morphology of the object to be measured based on the moving distance and surface morphology information.

[0097] Specifically, after the main control module 3 acquires the moving distance and surface morphology information, it can use the moving distance as the X-axis to represent the physical position of the scanning path and the surface morphology information as the Y-axis to represent the height change of the surface morphology of the object under test at the corresponding physical position of the scanning path, thereby generating a surface morphology distribution map of the object under test 01, so as to fully reflect the surface morphology of the object under test 01.

[0098] The surface topography measurement method for the object under test described above is implemented based on the lidar device provided in any embodiment of the present invention, and possesses the corresponding functional modules and beneficial effects of the lidar device. Technical details not described in detail in this embodiment can be found in the lidar device provided in any embodiment of the present invention.

[0099] Since the surface topography measurement method for the object under test described above is implemented based on the lidar device provided in any embodiment of the present invention, those skilled in the art can understand the specific implementation method and various variations of the surface topography measurement method for the object under test in this embodiment based on the lidar device described in the embodiments of the present invention. Therefore, how the surface topography measurement method for the object under test is implemented based on the lidar device in the embodiments of the present invention will not be described in detail here. As long as those skilled in the art implement the surface topography measurement method for the object under test based on the lidar device in the embodiments of the present invention, it falls within the scope of protection of this application.

[0100] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0101] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A lidar device for measuring the surface morphology of an object, characterized in that, include: At least one reference interferometry module, a measurement interferometry module, and a main control module; The reference interferometry module includes a reference photoelectric conversion unit and a reference scanning unit; The measurement interferometry module includes a measurement photoelectric conversion unit and a measurement scanning unit; The main control module is used to control the synchronous movement of the reference scanning unit and the measurement scanning unit; The reference photoelectric conversion unit is used to emit a reference laser signal to the reference scanning unit, and after receiving the reference detection optical signal fed back by the reference scanning unit, it generates a reference detection electrical signal based on the reference detection optical signal. The measurement photoelectric conversion unit is used to emit a measurement laser signal to the measurement scanning unit, and after receiving the measurement detection optical signal fed back by the measurement scanning unit, it generates a measurement detection electrical signal based on the measurement detection optical signal. The main control module is also used to determine the surface morphology of the object under test based on the reference detection electrical signal and the measurement detection electrical signal.

2. The lidar device according to claim 1, characterized in that, Also includes: A displacement stage and at least one fixed base; Both the reference scanning unit and the measurement scanning unit are disposed on the displacement stage; The reference photoelectric conversion unit and the measurement photoelectric conversion unit are disposed on the fixed base; The main control module is used to control the displacement stage to move the reference scanning unit and the measurement scanning unit.

3. The lidar device according to claim 2, characterized in that, At least one of the reference interferometry modules includes a first reference interferometry module; the reference photoelectric conversion unit and the measurement photoelectric conversion unit of the first reference interferometry module are located on the same side of the displacement stage.

4. The lidar device according to claim 3, characterized in that, The reference photoelectric conversion unit and the measurement photoelectric conversion unit of the first reference interferometer module are located on the same fixed base.

5. The lidar device according to claim 2, characterized in that, At least one of the reference interferometry modules includes a second reference interferometry module; the reference photoelectric conversion unit of the second reference interferometry module and the measurement photoelectric conversion unit are located on opposite sides of the displacement stage.

6. The lidar device according to claim 2, characterized in that, At least one of the reference interferometry modules includes a third reference interferometry module and a fourth reference interferometry module; The reference photoelectric conversion unit and the measurement photoelectric conversion unit of the third reference interferometry module are located on the same side of the displacement stage or on opposite sides of the displacement stage, respectively. The reference photoelectric conversion unit and the measurement photoelectric conversion unit of the fourth reference interferometry module are located on adjacent sides of the displacement stage, respectively.

7. The lidar device according to claim 1, characterized in that, The reference photoelectric conversion unit includes a reference silicon photonic chip and a reference laser; the reference scanning unit includes a first reflector; The reference laser is used to emit a reference laser signal to the reference silicon photonic chip; The reference silicon photonics chip is used to generate the reference laser signal and the reference oscillation signal according to the reference laser signal, and to emit the reference laser signal to the first reflector so that the first reflector reflects the reference laser signal; The reference silicon photonic chip is also used to receive the reference detection optical signal reflected by the first reflector, and to generate the reference detection electrical signal based on the reference oscillation signal and the reference detection optical signal.

8. The lidar device according to claim 7, characterized in that, The reference photoelectric conversion unit also includes a light adjustment subunit; The light adjustment subunit is located in the optical path between the reference silicon photonic chip and the first reflector; wherein, the light adjustment subunit includes a first collimating lens or a first focusing lens.

9. The lidar device according to claim 8, characterized in that, The reference scanning unit also includes a second focusing lens; The second focusing lens is located in the optical path between the light adjustment subunit and the first reflecting mirror.

10. The lidar device according to claim 1, characterized in that, The measurement photoelectric conversion unit includes a measurement silicon photonic chip and a measurement laser; the measurement scanning unit includes a second reflector; The measurement laser is used to emit measurement laser signals to the measurement silicon photonic chip; The measurement silicon photonics chip is used to generate the measurement laser signal and the measurement oscillation signal based on the measurement laser signal, and to emit the measurement laser signal to the second reflector so that the second reflector reflects the measurement laser signal; The measurement silicon photonic chip is also used to receive the measurement detection optical signal reflected by the second reflector, and to generate the measurement detection electrical signal based on the measurement oscillation signal and the measurement detection optical signal.

11. The lidar device according to claim 10, characterized in that, The measurement photoelectric conversion unit also includes a third focusing mirror; The third focusing lens is located in the optical path between the measuring silicon photonic chip and the second reflecting mirror.

12. The lidar device according to claim 1, characterized in that, Also includes: Image acquisition module; The image acquisition module is connected to the main control module. The image acquisition module is used to acquire surface image information of the object under test and provide the surface image information to the main control module. The main control module is also used to determine the effective scanning area based on the surface image information, and to control the reference scanning unit and the measurement scanning unit to move synchronously based on the effective scanning area.

13. The lidar device according to claim 1, characterized in that, Also includes: At least one reference signal modulation module corresponding one-to-one with at least one of the aforementioned reference interference modules; The reference signal modulation module is correspondingly disposed in the optical path between the reference photoelectric conversion unit and the reference scanning unit; and / or, The measurement signal modulation module is disposed in the optical path between the measurement photoelectric conversion unit and the measurement scanning unit.

14. A method for measuring the surface topography of an object under test based on a lidar device as described in any one of claims 1-13, characterized in that, include: After controlling the movement of the reference scanning unit and the measurement scanning unit, the main control module acquires the reference detection electrical signal provided by the reference photoelectric conversion unit and the measurement detection electrical signal provided by the measurement photoelectric conversion unit, respectively. The main control module determines the moving distance of the measurement scanning unit based on the reference detection electrical signal; The main control module determines the surface morphology information of the object under test based on the reference detection electrical signal and the measurement detection electrical signal; The main control module determines the surface morphology of the object under test based on the moving distance and the surface morphology information.

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