CN114963998A - Sub-nanometer level high-precision micro-displacement device for precision laser interferometry calibration and application - Google Patents

Abstract

The invention provides a sub-nanometer level high-precision micro-displacement device for precise laser interferometry calibration and application thereof.A differential capacitance micro-feedback is matched with an electrostatic suspension drive to carry out closed-loop control, so that the sub-nanometer level high-precision micro-displacement real-time monitoring is realized, and the sub-nanometer level high-precision micro-displacement device can be used as a reference of sub-nanometer level high-precision micro-displacement reference; meanwhile, the vibration influence of ground vibration noise on the sub-nanometer high-precision micro-displacement device is isolated by using an active vibration isolation table; a pyramid reflector is ingeniously inlaid on a floating substrate and used as a movable mirror of a precision laser interference measurement system, another fixed pyramid reflector is used as a static mirror, the floating substrate is driven by electrostatic suspension to drive the pyramid reflector to generate sub-nanometer quantitative micro-displacement, the quantitative micro-displacement of the pyramid reflector is measured by the precision laser interference measurement system, a quantitative calibration relation between a measurement result and the micro-displacement is established, and sub-nanometer displacement measurement calibration of the precision laser interference measurement system is completed.

Description

A sub-nanometer high-precision micro-displacement device for precision laser interferometry calibration and its application

technical field

The invention relates to the technical field of precision laser interferometry, in particular to a sub-nanometer-level high-precision micro-displacement device used for precision laser interferometry calibration and its application.

Background technique

Precision laser interferometry technology uses laser as the light source, with laser wavelength or laser frequency as the benchmark, and uses the principle of light interference to achieve positional accuracy (positioning accuracy, repeatability, etc.) of nanometer, sub-nanometer, and even picometer levels. It is widely used in industries such as CNC precision machining, basic metrology, precision positioning and ranging, high-end manufacturing, and the earth's gravitational field testing, gravitational gradient measurement, deep space laser communication, space gravitational wave detection and other aerospace fields. As a high-precision precision micro-displacement measurement system, although laser interferometry is mainly based on laser wavelength or laser frequency, the measurement accuracy of the entire system is also affected by other components of the measurement system. Quantitative calibration of micro-displacement measurement is a technical problem to be solved urgently by those skilled in the art.

SUMMARY OF THE INVENTION

The first objective of the present invention is to provide a sub-nanometer-level high-precision micro-displacement device for precision laser interferometry calibration in view of the deficiencies in the prior art.

For this reason, the above-mentioned purpose of the present invention is achieved through the following technical solutions:

A sub-nanometer-level high-precision micro-displacement device for precision laser interferometry calibration, characterized in that the sub-nanometer-level high-precision micro-displacement device for precision laser interferometry calibration comprises a fixed bottom plate, a fixed top plate and a A floating substrate in the space surrounded by the fixed bottom plate and the fixed top plate, a differential capacitive sensor is arranged between the fixed bottom plate and the fixed top plate, and the differential capacitive sensor includes a fixed capacitance upper plate and a constant capacitance lower pole plate and moving capacitor plate, the fixed capacitor upper plate is arranged on the lower surface of the fixed top plate, the constant capacitance lower plate is arranged on the upper surface of the fixed bottom plate, and the floating base plate is covered with a circle of dynamic capacitor electrodes. plate;

The floating substrate is provided with a cube corner mirror, and the position of the cube corner mirror is such that the light incident on the cube corner mirror can be returned without being blocked.

While adopting the above technical solutions, the present invention can also adopt or combine the following technical solutions:

As a preferred technical solution of the present invention, a support vertical plate is arranged between the fixed bottom plate and the fixed top plate, and the fixed bottom plate and the fixed top plate are both located on the same side of the support vertical plate.

As a preferred technical solution of the present invention, the fixed bottom plate is arranged on the active vibration isolation table.

As a preferred technical solution of the present invention, the position where the pyramid mirror is arranged on the floating substrate is hollow, and the weight of the hollowed-out part of the floating substrate is guaranteed to be the same as the weight of the pyramid mirror.

As a preferred technical solution of the present invention: the vertical projection of the moving capacitor plate includes and is greater than the vertical projection of the fixed capacitance lower plate and the fixed capacitance upper plate, and the vertical projection of the fixed capacitance lower plate and the constant capacitance upper plate The projections coincide.

As a preferred technical solution of the present invention, the floating base plate is processed and formed by a carbon fiber material with light weight and good rigidity.

As a preferred technical solution of the present invention: the corner mirror is made of BK7 glass material, and a high reflectivity film is coated based on the ion beam sputtering coating process with the coating material that best matches the lattice constant of the substrate.

Another object of the present invention is to provide the application of the above-mentioned sub-nanometer high-precision micro-displacement device for precision laser interferometry calibration in quantitative calibration of a precision laser interferometry system.

While adopting the above technical solutions, the present invention can also adopt or combine the following technical solutions:

As the preferred technical solution of the present invention: the application specifically includes the following steps:

S1. Load the driving voltage amplified by high voltage on the three capacitive plates of the differential capacitance sensor to generate electrostatic force. Adjusting the driving voltage loaded on the three capacitive plates can change the electrostatic force between the two adjacent plates and break the After the equilibrium state, under the action of electrostatic force, the floating substrate can be guaranteed to form a horizontal suspension in the space surrounded by the fixed bottom plate and the fixed top plate;

S2. After the floating substrate is suspended horizontally, continuing to adjust the relative magnitudes of the driving voltages loaded on the three capacitor plates can cause the floating substrate to produce sub-nanometer up and down translation in the vertical direction;

S3. After the position of the floating substrate is shifted in the vertical direction, the distance between the moving capacitor electrode plate and the fixed capacitor lower electrode plate and the fixed capacitor upper electrode plate will change accordingly, resulting in the upper and lower two parts of the differential capacitive sensor. The capacitance value of each capacitance sensor changes. Using the upper and lower capacitance sensors of the differential capacitance sensor, based on the differential capacitance micrometer technology, the tiny displacement of the floating substrate driven by electrostatic suspension can be measured with sub-nanometer high precision. real-time monitoring; using differential capacitance micrometer as real-time displacement feedback, with electrostatic suspension drive for closed-loop control, to ensure that the floating substrate can achieve sub-nanometer high-precision displacement under electrostatic suspension drive, which can be used as the displacement of precision laser interferometry Calibration reference datum;

S4. When calibrating precision laser interferometry, the cube mirror on the floating substrate is used as the moving mirror of the laser interferometry system, and the other fixed cube mirror is used as the static mirror. Quantitative micro-displacement at the nanometer level, using the precision laser interferometry system to measure the quantitative micro-displacement of the cube mirror, establish the quantitative calibration relationship between the measurement results and the micro-displacement, and complete the sub-nanometer measurement of the precision laser interferometry system. Level displacement measurement calibration.

The invention provides a sub-nanometer-level high-precision micro-displacement device for precision laser interferometry calibration and its application. The electrostatic suspension drive performs closed-loop control to realize real-time monitoring of high-precision micro-displacement of sub-nanometer level, and can be used as a reference for high-precision micro-displacement of sub-nanometer level. Vibration effects of high-precision micro-displacement device; ingeniously inlaid on the floating substrate of the sub-nanometer-level high-precision micro-displacement device, as the moving mirror of the precision laser interferometry system, and another fixed corner mirror as the static mirror Mirror, electrostatic suspension drives the floating substrate to drive the cube mirror to generate sub-nanometer quantitative micro-displacement, and use the precision laser interferometry system to measure the quantitative micro-displacement of the cube-corner mirror, and establish the quantitative between the measurement results and the micro-displacement. The calibration relationship is completed to complete the sub-nanometer displacement measurement calibration of the precision laser interferometry system.

Description of drawings

FIG. 1 is a structural diagram of a sub-nanometer-level high-precision micro-displacement device for precision laser interferometry calibration provided by the present invention.

Figure 2 is a schematic block diagram of the closed-loop control of differential capacitance micrometer feedback and electrostatic suspension drive.

3 is a schematic diagram of the application of the sub-nanometer high-precision micro-displacement device for precision laser interferometry calibration provided by the present invention in quantitative calibration of a precision laser interferometry system.

Detailed ways

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

As shown in Figure 1, a sub-nanometer high-precision micro-displacement device for precision laser interferometry calibration includes a fixed bottom plate 1, a supporting vertical plate 2, a fixed top plate 3, a floating base plate 4, a differential capacitance sensor 5, an angle The conical reflector 6 and the active vibration isolation table 7; the fixed bottom plate 1 and the fixed top plate 3 have the same outline dimensions, are parallel to the horizontal plane and are vertically installed at the upper and lower ends of the vertically placed support vertical plate 2, and are located in the support vertical plate 2 The width of the floating base plate 4 is slightly smaller than the width of the fixed top plate 3, after the suspension, ensure that the floating base plate 4 is parallel to the fixed top plate 3 and has no contact with the supporting vertical plate 2, and the length is greater than the length of the fixed top plate 3, and the floating base plate is guaranteed to be suspended after suspension. 4. The lengths of the two parts extending left and right in the length direction are the same; the differential capacitive sensor 5 is plated between the fixed bottom plate 1, the fixed top plate 3 and the floating base plate 4; In the middle position, the light incident on the cube mirror 6 can be returned without being blocked; the fixed base plate 1 is placed on the active vibration isolation table 7 .

The fixed bottom plate 1, the supporting vertical plate 2 and the fixed top plate 3 are made of aluminum alloy material, and the floating base plate 4 is made of carbon fiber material with light weight and good rigidity. The constant capacitance lower plate 5-1 and the constant capacitance upper plate 5-2 that constitute the differential capacitance sensor 5 are respectively plated on the upper surface of the fixed bottom plate 1 and the lower surface of the fixed top plate 3 by a gold plating process, and the dynamic capacitance plate 5-3 Then, it is plated on the surface of the floating substrate 4 by a gold-plating process. The vertical projections of the two pole plates of the fixed capacitor are the same, and the vertical projection of the moving capacitor pole plates includes and is greater than the vertical projection of the two pole plates of the fixed capacitor. Corner mirror 6 is realized with BK7 glass material, and the coating material with the best matching with the lattice constant of the substrate is selected, and the high reflectivity film is coated based on the ion beam sputtering coating process. The active vibration isolation table 7 is implemented by selecting the best commercial vibration isolation table with the best vibration isolation performance on the market.

Using the upper and lower capacitance sensors of the differential capacitance sensor 5, real-time displacement monitoring of sub-nanometer level can be realized based on the differential capacitance micrometer technology. Based on the differential capacitance micrometer feedback, and with the electrostatic suspension drive of the floating substrate 4 for closed-loop feedback control, sub-nanometer-level high-precision micro-displacement can be realized as a displacement reference.

The fixed base plate 1 is placed on the active vibration isolation table 7, and the active vibration isolation table 7 is used to isolate the vibration effect of the ground vibration noise on the sub-nanometer-level high-precision micro-displacement reference datum, so as to ensure the accuracy of the micro-displacement.

As shown in FIG. 1 , hollow out the middle position of the protruding part on the right side of the floating base plate 4 , and inlay a corner mirror 6 in the hollow, and precisely control the weight of the corner mirror 6 so that the weight of the floating base plate 4 is hollowed out. The weight of the dropped part is the same, which ensures that the floating substrate 4 can still maintain static balance after being suspended after the cube mirror 6 is mounted, and the light incident on the cube mirror 6 can return without being blocked.

As shown in FIG. 3 , the sub-nanometer high-precision micro-displacement device shown in FIG. 1 is matched with the precision laser interferometric measurement system, and the corner mirror 6 embedded in the right protruding part of the floating substrate 4 is used as the precision laser interferometric measurement system. The moving mirror can realize the high-precision displacement calibration of the sub-nanometer level for precision laser interferometry.

The application of the sub-nanometer high-precision micro-displacement device for precision laser interferometry calibration in the quantitative calibration of precision laser interferometry system, specifically, includes the following steps:

S1. As shown in FIG. 1 , the upper surface of the fixed bottom plate 1 is plated with the lower electrode plate 5-1 of the capacitor, the lower surface of the fixed top plate 3 is plated with the upper electrode plate 5-2 of the capacitor, and the surface of the floating substrate 4 is plated around the brake Capacitive electrode plates 5-3, two capacitive sensors are formed between the three capacitive electrode plates, and the upper and lower capacitive sensors form a differential capacitive sensor 5; The driving voltage can generate electrostatic force. As shown in Fig. 2, considering the gravitational effect of the floating substrate, the driving voltage loaded on the upper electrode plate 5-2 of the constant capacitor is U ₀ +U, and the driving voltage loaded on the lower electrode plate 5-1 of the constant capacitor is U ₀ -U, the driving voltage loaded on the dynamic capacitor plate 5-3 of the floating substrate 4 is 0, wherein U ₀ is the reference bias driving voltage, U is the control driving voltage, take U ₀ =1000V, and U is between 300~700V variable between. Adjusting the driving voltage loaded on the lower plate 5-1 of the constant capacitor and the upper plate 5-2 of the constant capacitor can change the electrostatic force between the two adjacent plates. It can ensure that the floating substrate 4 is suspended horizontally;

S2. After the floating substrate 4 is suspended horizontally, continue to adjust the relative magnitude of the driving voltages loaded on the two capacitor plates, the lower plate 5-1 of the constant capacitance and the upper plate 5-2 of the constant capacitance, which can cause the floating substrate 4 to move in the vertical direction. Generate sub-nanometer up and down translation;

S3. After the position of the floating substrate 4 is shifted in the vertical direction, the distance between the moving capacitor electrode plate 5-3 and the fixed capacitor lower electrode plate 5-1 and the fixed capacitor upper electrode plate 5-2 will change accordingly. As a result, the capacitance values of the upper and lower capacitance sensors C and C _of the _upper and lower capacitance sensors that constitute the differential capacitance sensor 5 are changed. As shown in FIG. 2 , using the upper and lower capacitive sensors of the differential capacitive sensor 5 , based on the differential capacitive micrometric technology, the tiny displacement generated by the electrostatic suspension drive of the floating substrate 4 can be monitored in real time with high precision of sub-nanometer level; The differential capacitance micrometer is further used as real-time displacement feedback, and the electrostatic suspension drive is used for closed-loop control to ensure that the floating substrate 4 can achieve sub-nanometer high-precision displacement under the electrostatic suspension drive, which can be used as a displacement calibration reference for precision laser interferometry. benchmark;

S4. As shown in Fig. 3, when the precision laser interferometry is calibrated, the cube mirror 6 embedded on the right side of the floating substrate 4 is used as the moving mirror of the laser interferometry system, and the other fixed cube mirror is used as the static mirror. The floating substrate 4 is levitated and driven to drive the cube mirror 6 to generate a quantitative micro-displacement of sub-nanometer level. The precise laser interferometry system is used to measure the quantitative micro-displacement of the cube-corner mirror 6, and the quantitative difference between the measurement result and the micro-displacement is established. The calibration relationship is used to complete the sub-nanometer displacement measurement calibration of the precision laser interferometry system.

The above-mentioned specific embodiments are used to explain the present invention, and are only preferred embodiments of the present invention, rather than limiting the present invention. Any modification or equivalent replacement made to the present invention is within the spirit of the present invention and the protection scope of the claims. , improvements, etc., all fall within the protection scope of the present invention.

Claims (9)

1. A sub-nanometer level high-precision micro-displacement device for precise laser interferometry calibration is characterized in that: the sub-nanometer high-precision micro-displacement device for precise laser interferometry calibration comprises a fixed bottom plate, a fixed top plate and a floating base plate arranged in a space surrounded by the fixed bottom plate and the fixed top plate, wherein a differential capacitance sensor is arranged between the fixed bottom plate and the fixed top plate and comprises a fixed capacitance upper pole plate, a fixed capacitance lower pole plate and a moving capacitance pole plate, the fixed capacitance upper pole plate is arranged on the lower surface of the fixed top plate, the fixed capacitance lower pole plate is arranged on the upper surface of the fixed bottom plate, and a circle of moving capacitance pole plate is wrapped on the outer surface of the floating base plate;

the floating substrate is provided with a pyramid reflector, and the pyramid reflector is positioned to enable light rays incident to the pyramid reflector to return without shielding.

2. The sub-nanometer level high precision micro displacement device for precision laser interferometry calibration according to claim 1, wherein: and a supporting vertical plate is arranged between the fixed bottom plate and the fixed top plate, and the fixed bottom plate and the fixed top plate are both positioned on the same side of the supporting vertical plate.

3. The sub-nanometer level high precision micro displacement device for precision laser interferometry calibration according to claim 1, wherein: the fixed bottom plate is arranged on the active vibration isolation table.

4. The sub-nanometer level high precision micro displacement device for precision laser interferometry calibration according to claim 1, wherein: the position of the floating substrate, which is provided with the pyramid reflector, is hollowed, and the weight of the hollowed-out part of the floating substrate is ensured to be consistent with that of the pyramid reflector.

5. The sub-nanometer level high precision micro displacement device for precision laser interferometry calibration according to claim 1, wherein: the vertical projection of the dynamic capacitor plate comprises and is larger than the vertical projection of the fixed capacitor lower plate and the fixed capacitor upper plate, and the vertical projections of the fixed capacitor lower plate and the fixed capacitor upper plate are overlapped.

6. The sub-nanometer level high precision micro displacement device for precision laser interferometry calibration according to claim 1, wherein: the floating substrate is formed by processing a carbon fiber material with light weight and good rigidity.

7. The sub-nanometer level high precision micro displacement device for precision laser interferometry calibration according to claim 1, wherein: the pyramid reflector is made of BK7 glass material, and a high-reflectivity film is plated on the basis of an ion beam sputtering coating process by selecting a coating material which is best matched with the substrate lattice constant.

8. The use of the sub-nanometer level high precision micro-displacement device for precision laser interferometry calibration according to claim 1 for quantitative calibration of precision laser interferometry systems.

9. Use according to claim 8, characterized in that: the application comprises the following steps:

s1, loading high-voltage amplified driving voltages on three capacitor plates of the differential capacitance sensor to generate electrostatic force, adjusting the driving voltages loaded on the three capacitor plates to change the electrostatic force between the two adjacent plates, and after the balance state is broken, ensuring that the floating substrate forms horizontal suspension in a space surrounded by the fixed bottom plate and the fixed top plate under the action of the electrostatic force;

s2, after the floating substrate is horizontally suspended, the relative magnitude of driving voltages loaded on the three capacitor plates is continuously adjusted to cause the floating substrate to generate sub-nanometer level up-and-down translation in the vertical direction;

s3, after the floating substrate is translated in the vertical direction, the distances between a dynamic capacitor polar plate and a fixed capacitor lower polar plate and between the dynamic capacitor polar plate and the fixed capacitor upper polar plate are correspondingly changed, so that the capacitance values of an upper capacitance sensor and a lower capacitance sensor which form a differential capacitance sensor are changed, and the micro displacement generated by the static suspension driving of the floating substrate can be subjected to sub-nanometer high-precision real-time monitoring by utilizing the upper capacitance sensor and the lower capacitance sensor of the differential capacitance sensor and based on a differential capacitance micrometering technology; differential capacitance micrometering is used as real-time displacement feedback and is matched with electrostatic suspension driving to carry out closed-loop control, so that the floating substrate can realize sub-nanometer-level high-precision displacement under the electrostatic suspension driving, and can be used as a displacement calibration reference for precision laser interferometry;

s4, when the precise laser interference measurement is calibrated, the pyramid reflector on the floating substrate is used as a movable mirror of the laser interference measurement system, the other fixed pyramid reflector is used as a static mirror, the floating substrate is driven by electrostatic suspension to drive the pyramid reflector to generate sub-nanometer quantitative micro-displacement, the quantitative micro-displacement of the pyramid reflector is measured by the precise laser interference measurement system, the quantitative calibration relation between the measurement result and the micro-displacement is established, and the sub-nanometer displacement measurement calibration of the precise laser interference measurement system is completed.

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