A laser measuring device and a measuring method

Abstract

This invention relates to the field of optical measurement technology, and more particularly to a laser measurement device and method. The laser measurement device includes: a first receiving portion containing a first vacuum cavity, in which a laser interferometer is located; a second receiving portion containing a second vacuum cavity, in which a target mirror assembly is located; a measuring bellows, the first end of which is connected to the first receiving portion, the second end of which is connected to the second receiving portion; a compensating bellows, the first end of which is connected to the second receiving portion, and the second end of which is connected to a vacuum adjustment device; a motor first moves the second receiving portion a preset distance toward the laser interferometer, and the second receiving portion is subjected to a first force applied by the measuring bellows; the vacuum adjustment device adjusts the negative pressure inside the compensating bellows to a target pressure, so that the second force applied to the second receiving portion by the compensating bellows is the same in magnitude and opposite in direction to the first force. This invention at least helps to reduce thermal interference during the measurement process.

Description

Technical Field

[0001] This invention belongs to the field of optical measurement technology, and particularly relates to a laser measurement device and measurement method. Background Technology

[0002] In high-end manufacturing fields such as semiconductors and aerospace, precision displacement measurement is increasingly becoming a critical requirement. Laser interferometers are the core measurement tool for achieving this goal. The sources of error in their measurement accuracy are complex and diverse, mainly including errors inherent to the interferometer system itself, equipment geometric errors, installation alignment errors, optical path errors caused by environmental factors, and time drift errors. These errors are often coupled and jointly constrain the final measurement performance of the interferometer. Among the many errors, environmental errors are particularly prominent. They arise from changes in factors such as temperature, humidity, atmospheric pressure, gas composition, and their fluctuations in the measurement environment, causing changes in the wavelength of light during its propagation in the air, thus causing the measurement results to deviate from the true value. To ensure measurement accuracy, it is usually necessary to monitor environmental parameters in real time to compensate for the laser wavelength, or to perform high-precision control of the measurement environment.

[0003] The uncertainty obtained by measuring air pressure P, temperature T, and humidity F and compensating using the Edlén formula is approximately 1 × 10⁻⁶. -7 ~5×10 -7 Within the range of precision, as the requirements for accuracy enter the nanoscale, the compensation accuracy of such compensation methods can hardly meet the requirements of long-term stability and repeatability of measurements. In order to ensure the stability of the measurement environment of laser interferometer, the existing schemes generally use a vacuum environment to replace the conventional atmospheric environment, that is, to build a large vacuum laboratory or vacuum cavity and place the laser interferometer, optical path and the object under test completely in a vacuum environment. This method is considered to be an extremely effective anti-interference means, which can significantly improve the long-term stability and repeatability of displacement measurement.

[0004] When the object under test cannot be placed in a vacuum environment due to its structure or material properties, for example, its size may change due to expansion when placed in a vacuum, leading to measurement deviation, it is necessary to place the optical path of the interferometer in a vacuum while the object under test remains under atmospheric conditions. In order to ensure that the optical part maintains a vacuum state during motion measurement, a metal bellows with good sealing performance and extensibility is usually used as a sealing component, which is placed outside the moving optical path, thereby maintaining the integrity of the vacuum environment while realizing motion measurement.

[0005] Analysis revealed that while using a bellows-encased optical path effectively maintains the vacuum state of the optical path and allows external objects to move, this structure also introduces significant mechanical load issues. Because the bellows is inside a vacuum and outside is under atmospheric pressure, its cavity is subjected to continuous atmospheric pressure. This forces the moving optical path to overcome enormous resistance during movement. Consequently, the driving source, such as the motor driving the object under test, needs to continuously output tremendous thrust to resist this vacuum force, significantly increasing the system's power requirements. Under high-power operation, the driving source, such as the motor, will inevitably radiate heat into the surrounding environment, causing local temperature rises and thermal fluctuations. This may interfere with the stability of optical components, cause changes in the air refractive index, or lead to thermal deformation of the mechanical structure, ultimately negatively impacting the high-precision interferometric measurement environment. Summary of the Invention

[0006] In view of this, the present invention aims to provide a laser measurement device and measurement method, which at least helps to reduce thermal interference during the measurement process.

[0007] To achieve the above objectives, the technical solution created by this invention is implemented as follows: This invention provides a laser measurement device, comprising: a first receiving portion having a first vacuum cavity; a laser interferometer located within the first vacuum cavity; a second receiving portion having a second vacuum cavity; a target mirror assembly located within the second vacuum cavity; a length-measuring bellows, with a first end connected to the first receiving portion and a second end connected to the second receiving portion, the first vacuum cavity, the inner ring of the length-measuring bellows, and the second vacuum cavity being interconnected; a compensation bellows and a vacuum adjustment device, wherein the compensation bellows... The first end of the corrugated tube is connected to the second receiving part, and the inner ring of the compensating corrugated tube is spaced apart from the second vacuum cavity. The second end of the compensating corrugated tube is connected to the vacuum adjustment device. The motor is connected to the second receiving part. When the measurement starts, the motor first drives the second receiving part to move a preset distance toward the laser interferometer. The second receiving part is subjected to the first force applied by the measuring corrugated tube. The vacuum adjustment device adjusts the negative pressure of the inner ring of the compensating corrugated tube to the target pressure so that during the measurement process, the second force applied by the compensating corrugated tube to the second receiving part is the same in magnitude and opposite in direction to the first force.

[0008] Furthermore, in the initial state, the length of the measuring bellows is the original length of the measuring bellows, and the length of the compensating bellows is the length of the compensating bellows when it has the maximum compression.

[0009] Furthermore, the first vacuum chamber, the inner ring of the measuring bellows, and the second vacuum chamber constitute a measuring vacuum chamber. The first force is the resultant force of the vacuum force of the measuring vacuum chamber and the elastic force of the measuring bellows. The negative pressure of the measuring vacuum chamber remains unchanged, and the vacuum force of the measuring vacuum chamber remains unchanged. The inner ring of the compensating bellows constitutes a compensating vacuum chamber. The second force is the resultant force of the vacuum force of the compensating vacuum chamber and the elastic force of the compensating bellows.

[0010] Furthermore, the minimum value of the preset distance is 0, and the maximum value of the preset distance is the maximum compression of the measuring bellows.

[0011] Further, definition As the first force, ,in, To measure the negative pressure in the vacuum chamber, To measure the effective area of ​​a long corrugated pipe, This represents the vacuum force in the measuring vacuum chamber. To measure the elastic modulus of a long corrugated pipe, For the preset distance, Represents the elastic force of the measuring bellows; definition As the second force, ,in, To compensate for the negative pressure in the vacuum chamber, To compensate for the effective area of ​​the bellows, This represents the vacuum force in the compensation vacuum chamber. To compensate for the elastic modulus of the bellows, To compensate for the maximum compression of the bellows, The second receiving part is moved a preset distance towards the laser interferometer. The actual compression of the post-compensation bellows This represents the elasticity of the compensating bellows.

[0012] Furthermore, target pressure , .

[0013] Furthermore, the measuring bellows is the same as the compensating bellows. The original length of the measuring bellows is the same as the original length of the compensating bellows. The elastic coefficient of the measuring bellows is the same as the elastic coefficient of the compensating bellows. The maximum compression of the measuring bellows is the same as the maximum compression of the compensating bellows.

[0014] Furthermore, during the measurement process, the laser interferometer emits a measurement laser, which is transmitted to the target mirror group through the inner ring of the measuring bellows. The target mirror group generates a return beam based on the measurement laser, and the return beam is transmitted to the laser interferometer through the inner ring of the measuring bellows.

[0015] Furthermore, the second receiving part is connected to the motion stage that carries the object to be measured; the laser measuring device also includes a cable and at least one steering pulley, the first end of the compensating bellows is connected to the second receiving part through the cable, and the steering pulley is mounted on the cable; the laser measuring device also includes a vacuum pump group, which is connected to the first receiving part; the vacuum regulating device includes a vacuum regulating valve, a vacuum generator, and a vacuum pipeline, the second end of the compensating bellows is connected to the vacuum generator through the vacuum pipeline, and the vacuum regulating valve is mounted on the vacuum pipeline.

[0016] In another aspect, this invention provides a laser measurement method based on the aforementioned laser measurement device. The laser measurement method includes: at the start of measurement, a motor drives a second receiving part to move a preset distance toward a laser interferometer; after the second receiving part is in position, it is subjected to a first force applied by a measuring bellows; a vacuum adjustment device is used to adjust the negative pressure of the inner ring of the compensating bellows to the target pressure to ensure that the second force applied to the second receiving part by the compensating bellows is the same in magnitude and opposite in direction to the first force, thereby reducing the load on the motor; during the measurement process, displacement measurement is achieved using a laser interferometer and a target mirror group.

[0017] Compared with the prior art, the present invention can achieve the following beneficial effects: The laser measuring device and measuring method provided by the present invention achieve force balance based on the compensating bellows to reduce thermal interference during the measurement process. Specifically, in the laser measuring device provided by the present invention, the measuring optical path is mainly wrapped with a measuring bellows. The second receiving part set at the second end of the measuring bellows is connected to the motion stage carrying the object to be measured. The compensating bellows with internal vacuum is connected to the second receiving part. The negative pressure of the inner ring of the compensating bellows is adjusted by the vacuum adjustment device. The elasticity of the compensating bellows and the vacuum force are used to balance the resultant force of the vacuum force and elasticity on the measuring bellows during the measurement process, thereby reducing the load on the motor. Using a compensating bellows of the same type and environment as the measuring bellows can ensure that the measuring bellows and the compensating bellows have good displacement consistency. This can significantly reduce the load on the motor during measurement, reduce the output power and heat generation of the motor. At the same time, the bellows itself hardly generates heat, and the heat source is concentrated on the vacuum pump or vacuum generator at a distance, thereby effectively mitigating the impact of thermal effects on the precision measurement environment and helping to reduce thermal interference during the measurement process. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram of the structure of the laser measuring device described in the embodiment of the present invention; Figure 2 A force diagram of the laser measuring device described in the embodiments of the present invention; Figure 3 The first force, the vacuum force of the measuring vacuum chamber, the elastic force of the measuring bellows, the second force, the vacuum force of the compensating vacuum chamber, and the elastic force of the compensating bellows are all considered as follows: A diagram illustrating the changing trend of the changes; Figure 4 A flowchart of the measurement method described in the embodiments of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] refer to Figure 1 and Figure 2 This invention provides a laser measurement device, comprising: a first receiving portion 2 having a first vacuum cavity; a laser interferometer 3 located within the first vacuum cavity; a second receiving portion 6 having a second vacuum cavity; a target mirror group 7 located within the second vacuum cavity; a length measuring bellows 4, the first end of which is connected to the first receiving portion 2, and the second end of which is connected to the second receiving portion 6; the first vacuum cavity, the inner ring of the length measuring bellows 4, and the second vacuum cavity being interconnected; a compensation bellows 10 and a vacuum adjustment device, the first end of which is connected to the second receiving portion 6. The receiving part 6 is connected to the second vacuum chamber, and the inner ring of the compensating bellows 10 is spaced apart from the second vacuum chamber. The second end of the compensating bellows 10 is connected to the vacuum adjustment device. The motor 5 is connected to the second receiving part 6. When the measurement starts, the motor 5 first drives the second receiving part 6 to move a preset distance toward the laser interferometer 3. The purpose is to make the target mirror group 7 move synchronously with the object to be measured. The second receiving part 6 is subjected to the first force applied by the measuring bellows 4. The vacuum adjustment device adjusts the negative pressure of the inner ring of the compensating bellows 10 to the target pressure so that during the measurement process, the second force applied by the compensating bellows 10 to the second receiving part 6 is the same in magnitude and opposite in direction to the first force.

[0025] It should be noted that the laser measuring device uses laser to measure the displacement of the object under test. The second receiving part moves synchronously with the object under test. When the motor 5 drives the second receiving part 6 to move a preset distance toward the laser interferometer 3, the motor 5 also drives the object under test to move a preset distance toward the laser interferometer 3.

[0026] Furthermore, in the initial state, the length of the measuring bellows 4 is the original length of the measuring bellows, and the length of the compensating bellows 10 is the length of the compensating bellows 10 when it has the maximum compression.

[0027] Furthermore, the first vacuum chamber, the inner ring of the measuring bellows 4, and the second vacuum chamber constitute a measuring vacuum chamber. The first force is the resultant force of the vacuum force of the measuring vacuum chamber and the elastic force of the measuring bellows 4. The negative pressure of the measuring vacuum chamber remains unchanged, and the vacuum force of the measuring vacuum chamber remains unchanged. The inner ring of the compensating bellows 10 constitutes a compensating vacuum chamber. The second force is the resultant force of the vacuum force of the compensating vacuum chamber and the elastic force of the compensating bellows 10.

[0028] Furthermore, the minimum value of the preset distance is 0, and the maximum value of the preset distance is the maximum compression of the measuring bellows 4.

[0029] Further, definition As the primary force, under the idealized condition where friction is neglected and pressure control ensures stability, ,in, To measure the negative pressure in the vacuum chamber, To measure the effective area of ​​the long bellows 4 (or the effective area of ​​the vacuum cavity). This represents the vacuum force in the measuring vacuum chamber. To measure the elastic modulus of the long corrugated pipe 4, For the preset distance, Represents the elastic force of the measuring bellows 4; Definition As the second force, in the idealized case where friction is neglected and pressure controls stability, ,in, To compensate for the negative pressure in the vacuum chamber, To compensate for the effective area of ​​the bellows 10, This represents the vacuum force in the compensation vacuum chamber. To compensate for the elastic modulus of the bellows 10, To compensate for the maximum compression of the bellows 10, The second housing 6-axis laser interferometer 3 is moved a preset distance. The actual compression of the post-compensation bellows 10 This represents the elasticity of the compensating bellows 10.

[0030] Furthermore, target pressure The purpose of the vacuum regulating device in adjusting the negative pressure of the inner ring of the compensating bellows 10 is to ensure... .

[0031] Furthermore, the measuring bellows 4 is identical to the compensating bellows 10. The original length of the measuring bellows 4 is the same as the original length of the compensating bellows 10, the elastic modulus of the measuring bellows 4 is the same as the elastic modulus of the compensating bellows 10, and the maximum compression of the measuring bellows 4 is the same as the maximum compression of the compensating bellows 10. By using the compensating bellows 10, which is in the same environment and of the same type as the measuring bellows 4, good displacement consistency between the measuring bellows 4 and the compensating bellows 10 can be ensured, thereby achieving precise force compensation.

[0032] Furthermore, during the measurement process, the laser interferometer 3 is used to emit a measurement laser. The measurement laser is transmitted to the target mirror group 7 through the inner circle of the length measuring corrugated tube 4. The target mirror group 7 generates a return light based on the measurement laser. The return light is transmitted to the laser interferometer 3 through the inner circle of the length measuring corrugated tube 4.

[0033] Furthermore, the second receiving part 6 is connected to the motion stage 13 that carries the object to be measured, and the motor 5 is connected to the second receiving part 6 through the motion stage 13; the laser measuring device also includes a cable 8 and at least one steering pulley 9, the first end of the compensating bellows 10 is connected to the second receiving part 6 through the cable 8, and the steering pulley 9 is disposed on the cable 8; the laser measuring device also includes a vacuum pump group 1, which is connected to the first receiving part 2; the vacuum regulating device includes a vacuum regulating valve 11, a vacuum generator 12, and a vacuum pipeline, the second end of the compensating bellows 10 is connected to the vacuum generator 12 through the vacuum pipeline, and the vacuum regulating valve 11 is disposed on the vacuum pipeline.

[0034] Understandably, when motor 5 drives the motion table 13, the measuring bellows 4 and the compensating bellows 10 will extend and retract accordingly. When the measuring bellows 4 compresses, the compensating bellows 10 extends; when the measuring bellows 4 extends, the compensating bellows 10 compresses. Furthermore, the amount of extension and retraction of the compensating bellows 10 and the measuring bellows 4 is consistent, and both amounts are the preset distance the motion table 13 moves. The second force generated by the compensating bellows 10 serves as a compensating force, which is transmitted to the motion table 13 through the cable 8, making the forces on both ends of the motion table 13 as equal as possible.

[0035] In some embodiments, the measuring corrugated tube and the compensating corrugated tube are arranged in parallel. The laser measuring device includes two steering pulleys 9, which are arranged on the cable 8 to change the extension direction of the cable 8, thereby ensuring that the measuring corrugated tube and the compensating corrugated tube are arranged in parallel.

[0036] refer to Figure 2 In some examples, the entire laser measurement device can be mounted on the marble base 14. The following is a force analysis of the motion stage 13. It can be understood that the force analysis of the motion stage 13 is equivalent to the force analysis of the second receiving part 6. At the start of the measurement, the motor 5 drives the motion stage 13, causing the measuring bellows 4 to be continuously compressed from its original length, thus changing the force on the measuring bellows 4. At this time, the motion stage 13 is subjected to four forces: the vacuum force generated by evacuating the measuring vacuum chamber. F 测真 4. The elastic force generated by the compression of the long corrugated pipe F 测弹 The driving force of motor 5 F 电机 Compensating force transmitted by cable 8 F 绳子 Compensating force transmitted by the cable F 绳子 This is to compensate for the vacuum force generated by evacuating the vacuum chamber. F 补真 Elastic force generated by the expansion and contraction of the compensating bellows 10 F补弹 The resultant force, i.e. the second force, is to reduce the heat generated by motor 5. F 电机 It needs to be as small as possible, ideally. F 电机 It should be 0, meaning it measures the vacuum force generated by evacuating the vacuum chamber. F 测真 And the elastic force generated by the compression of the long corrugated pipe 4 F 测弹 The resultant force (i.e., the first force) on the motion platform 13 should be completely canceled out by the second force. (Reference) Figure 2 and Figure 3 As the measuring bellows 4 is continuously compressed, its elastic force gradually increases. The pressure difference between the inside and outside of the measuring vacuum chamber remains constant at one atmosphere, and the vacuum force of the measuring vacuum chamber... F 测真 Unchanged; the compensating bellows 10 is driven to extend, and its elasticity gradually decreases. The compensating bellows 10 changes its internal pressure by regulating the airflow rate through the vacuum regulating valve 11. The vacuum force of the compensating vacuum chamber is adjusted in real time by relying on the pressure difference between the inside and outside to balance the changing force during the extension and retraction of the measuring bellows 4. Ideally, the first force should be equal in magnitude to the second force, which is manifested as Figure 3 When the dotted line coincides with the solid line, the supply load of motor 5 is minimized, effectively reducing the impact of heat generated by motor 5 on the measurement environment.

[0037] Motor 5 drives the motion table 13 to move, which in turn compresses the measuring bellows 4. The measuring bellows 4 generates elastic force, and the vacuum force of the measuring vacuum chamber remains unchanged. In order to prevent motor 5 from generating a load, a second force is used to compensate for the driving force of motor 5. Since the measuring bellows 4 and the compensating bellows 10 are connected by a cable 8, the length change of the measuring bellows 4 is consistent with the length change of the compensating bellows 10. Therefore, the target pressure to be adjusted in the compensating vacuum chamber can be obtained based on the negative pressure of the measuring vacuum chamber, the effective area of ​​the measuring bellows 4, the elastic coefficient of the measuring bellows 4, the preset distance, the effective area of ​​the compensating bellows 10, the elastic coefficient of the compensating bellows 10, and the maximum compression of the compensating bellows 10.

[0038] Understandably, when the length of the measuring bellows 4 is the same as its original length, the measuring bellows 4 has no elasticity, and the compensating bellows 10 is compressed to the maximum. At this time, the negative pressure in the compensating vacuum chamber is at its maximum. , This represents the maximum negative pressure in the compensation vacuum chamber. When the measuring bellows 4 reaches its maximum compression, the object under test moves to its maximum range, the length of the compensation bellows 10 is its original length, and the compensation bellows 10 has no elasticity. At this time, the negative pressure in the compensation vacuum chamber is at its minimum. , This represents the minimum negative pressure of the compensating vacuum chamber. In summary, the negative pressure adjustment range of the compensating vacuum chamber is as follows: .

[0039] In another aspect, this invention provides a laser measurement method based on the aforementioned laser measurement device. The laser measurement method includes: at the start of measurement, using a motor 5 to move a second receiving part 6 a preset distance toward a laser interferometer 3; after the second receiving part 6 is in position, it is subjected to a first force applied by a measuring bellows 4; using a vacuum adjustment device to adjust the negative pressure of the inner ring of the compensating bellows 10 to the target pressure, so as to ensure that the second force applied to the second receiving part 6 by the compensating bellows 10 is the same in magnitude and opposite in direction to the first force, thereby reducing the load on the motor 5; during the measurement process, displacement measurement is achieved using the laser interferometer 3 and the target mirror group 7.

[0040] In some embodiments, reference Figure 4 At the start of the measurement, a vacuum measurement environment is first established. Then, motor 5 drives the second receiving part 6 to move towards the laser interferometer 3, that is, motor 5 drives the motion stage 13 to move. The current displacement of the motion stage 13 is then obtained. The target pressure is calculated, and the negative pressure of the inner ring of the compensating bellows 10 is adjusted to the target pressure using the vacuum regulating device. That is, the vacuum regulating device adjusts the negative pressure of the compensating vacuum chamber to the target pressure. The second force is applied to the motion table 13 through the cable 8 to balance the load. The driving force of the motor 5 is reduced to reduce the load and heat generation. Then it is determined whether the motion should continue. If the motion continues, the load is balanced in the aforementioned manner. If the motion stops, the second force is maintained unchanged, the motion table 13 is stationary, and the measurement ends.

[0041] The laser measurement device and method provided by this invention, based on the traditional vacuum bellows laser interferometric displacement measurement optical path structure, introduces a set of compensating bellows 10 of the same type as the measuring bellows 4. This is used to dynamically balance the combined force of the vacuum force and elastic force on the measuring bellows 4 during its extension and retraction motion, thereby significantly reducing the driving load of the motor 5. In addition, the laser measurement device and method provided by this invention have the following significant advantages: First, while maintaining the vacuum state of the optical path, it allows the object under test to be placed in an atmospheric environment, which can effectively isolate the vacuum measurement environment from the environment where the object under test is located, and is especially suitable for high-precision measurement of objects in an atmospheric environment; Second, the adjustment system composed of the compensating bellows 10 and the vacuum adjustment device helps to reduce the load on the motor 5, and keeps the heat sources such as the motor 5, vacuum pump group and vacuum generator 12 away from the measurement system, reducing the impact of heat generation on the measurement environment; Third, the entire device has a simple mechanical structure, high modularity, is easy to integrate, and supports flexible motion control and vacuum adjustment, making it suitable for multi-axis laser interferometer systems.

[0042] 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 disclosure 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.

[0043] 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 laser measuring device, characterized in that, include: A first receiving portion, wherein the first receiving portion has a first vacuum cavity; A laser interferometer, wherein the laser interferometer is located in the first vacuum cavity; The second receiving part has a second vacuum cavity inside; The target mirror assembly is located in the second vacuum chamber; A length-measuring corrugated tube, wherein the first end of the length-measuring corrugated tube is connected to the first receiving part, the second end of the length-measuring corrugated tube is connected to the second receiving part, and the first vacuum chamber, the inner ring of the length-measuring corrugated tube and the second vacuum chamber are connected in communication. The compensation bellows and vacuum regulating device are provided. The first end of the compensation bellows is connected to the second receiving part, and the inner ring of the compensation bellows is spaced apart from the second vacuum cavity. The second end of the compensation bellows is connected to the vacuum regulating device. An electric motor, which is connected to the second receiving portion; When the measurement begins, the motor first drives the second receiving part to move a preset distance toward the laser interferometer. The second receiving part is subjected to a first force applied by the measuring bellows. The vacuum adjustment device adjusts the negative pressure of the inner ring of the compensating bellows to the target pressure so that during the measurement process, the second force applied by the compensating bellows to the second receiving part is the same in magnitude and opposite in direction to the first force.

2. The laser measuring device according to claim 1, characterized in that, In the initial state, the length of the measuring bellows is the original length of the measuring bellows, and the length of the compensating bellows is the length of the compensating bellows when it has the maximum compression.

3. The laser measuring device according to claim 2, characterized in that, The first vacuum chamber, the inner ring of the measuring bellows, and the second vacuum chamber constitute a measuring vacuum chamber. The first force is the resultant force of the vacuum force of the measuring vacuum chamber and the elastic force of the measuring bellows. The negative pressure of the measuring vacuum chamber remains unchanged, and the vacuum force of the measuring vacuum chamber remains unchanged. The inner ring of the compensating bellows forms a compensating vacuum cavity, and the second force is the resultant force of the vacuum force of the compensating vacuum cavity and the elastic force of the compensating bellows.

4. The laser measuring device according to claim 2, characterized in that, The minimum preset distance is 0, and the maximum preset distance is the maximum compression of the measuring bellows.

5. The laser measuring device according to claim 3, characterized in that, definition As the first force, ,in, To measure the negative pressure in the vacuum chamber, To measure the effective area of ​​a long corrugated pipe, This represents the vacuum force in the measuring vacuum chamber. To measure the elastic modulus of a long corrugated pipe, For the preset distance, Represents the elasticity of the measuring bellows; definition As the second force, ,in, To compensate for the negative pressure in the vacuum chamber, To compensate for the effective area of ​​the bellows, This represents the vacuum force in the compensation vacuum chamber. To compensate for the elastic modulus of the bellows, To compensate for the maximum compression of the bellows, The second receiving part is moved a preset distance towards the laser interferometer. The actual compression of the post-compensation bellows This represents the elasticity of the compensating bellows.

6. The laser measuring device according to claim 5, characterized in that, Target pressure , .

7. The laser measuring device according to claim 2, characterized in that, The measuring bellows is the same as the compensating bellows. The original length of the measuring bellows is the same as the original length of the compensating bellows. The elastic coefficient of the measuring bellows is the same as the elastic coefficient of the compensating bellows. The maximum compression of the measuring bellows is the same as the maximum compression of the compensating bellows.

8. The laser measuring device according to claim 1, characterized in that, During the measurement process, the laser interferometer emits a measurement laser, which is transmitted to the target mirror group through the inner ring of the length measuring corrugated tube. The target mirror group generates a return beam based on the measurement laser, and the return beam is transmitted to the laser interferometer through the inner ring of the length measuring corrugated tube.

9. The laser measuring device according to claim 1, characterized in that, The second receiving part is connected to the motion table that carries the object to be measured; The laser measuring device also includes a cable and at least one steering pulley. The first end of the compensating bellows is connected to the second receiving part through the cable, and the steering pulley is disposed on the cable. The laser measurement device also includes a vacuum pump assembly, which is connected to the first receiving portion; The vacuum regulating device includes a vacuum regulating valve, a vacuum generator, and a vacuum pipeline. The second end of the compensating bellows is connected to the vacuum generator through the vacuum pipeline, and the vacuum regulating valve is located on the vacuum pipeline.

10. A laser measurement method, characterized in that, The laser measurement method is implemented based on the laser measurement device according to any one of claims 1 to 9, and the laser measurement method includes: When the measurement begins, the motor drives the second receiving part to move a preset distance toward the laser interferometer. After the second receiving part moves into place, the second receiving part is subjected to the first force applied by the measuring bellows. The negative pressure of the inner ring of the compensating bellows is adjusted to the target pressure using a vacuum regulating device to ensure that the second force applied to the second receiving part by the compensating bellows is the same in magnitude and opposite in direction to the first force, thereby reducing the load on the motor. During the measurement process, displacement measurement is achieved using a laser interferometer and a target mirror group.

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