CN110514147B - Double-frequency laser interferometer capable of simultaneously measuring roll angle and straightness - Google Patents
Double-frequency laser interferometer capable of simultaneously measuring roll angle and straightness Download PDFInfo
- Publication number
- CN110514147B CN110514147B CN201910728477.4A CN201910728477A CN110514147B CN 110514147 B CN110514147 B CN 110514147B CN 201910728477 A CN201910728477 A CN 201910728477A CN 110514147 B CN110514147 B CN 110514147B
- Authority
- CN
- China
- Prior art keywords
- beam splitter
- light
- reflector
- frequency laser
- measurement
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/26—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/26—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes
- G01B11/27—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes for testing the alignment of axes
- G01B11/272—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes for testing the alignment of axes using photoelectric detection means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B9/00—Measuring instruments characterised by the use of optical techniques
- G01B9/02—Interferometers
- G01B9/02015—Interferometers characterised by the beam path configuration
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Instruments For Measurement Of Length By Optical Means (AREA)
Abstract
The invention discloses a double-frequency laser interferometer capable of simultaneously measuring a roll angle and straightness, which comprises a double-frequency laser head and a neutral spectroscope, wherein a first polarized beam splitter, a second polarized beam splitter and a reference reflector are sequentially arranged on a first measuring light path formed by transmission or reflection of the neutral spectroscope, a plane reflector, the first polarized beam splitter, the second polarized beam splitter and the reference reflector are sequentially arranged on a second measuring light path formed by reflection or transmission of the neutral spectroscope, and the second polarized beam splitter, the first polarized beam splitter and a first polarized photoelectric receiver/a second polarized photoelectric receiver are also sequentially positioned on a light path of light returning from the first measuring light path/the second measuring light path after being reflected from the reference reflector. The invention can simultaneously complete the measurement of the roll angle and the straightness, not only reduces the number of optical parts, but also reduces the workload in the adjustment process by half, and can eliminate the roll angle error caused by the unparallel of the first measuring light and the second measuring light, thereby greatly improving the measurement precision.
Description
Technical Field
The invention belongs to the technical field of laser precision measurement, and particularly relates to a dual-frequency laser interferometer for simultaneously measuring a roll angle and straightness by using laser.
Background
Roll angle measurement and straightness measurement are the most basic measurement items in the field of geometric measurement, and are widely applied to precision verification, error compensation and the like of equipment such as a moving guide rail, a coordinate measuring machine, a machine tool and the like.
In the aspect of straightness measurement, a method for measuring straightness by using a dual-frequency laser is provided by Yinchangyong, Qinghua university and the like. The implementation device of the method is shown in fig. 1, and comprises: the two-frequency laser device comprises a two-frequency laser light source 101, a beam splitter 102, first and second Wollaston prisms 105 and 106 and a right-angle prism 107, a first analyzer 103, a first photoelectric receiver 104, a second analyzer 108 and a second photoelectric receiver 109 which are respectively arranged on a reflection light path of the beam splitter 102 and a return light path of the Wollaston prism 105, and a signal processing unit which is connected with the two photoelectric receivers 104 and 109 and consists of a signal amplifying circuit, a phase meter 110 and a computer 111.
The dual-frequency laser light source 101 directly emits two linearly polarized lights with different frequencies and orthogonal with each other; the beam splitting angles of the two Wollaston prisms 105 and 106 are completely the same; the dual-frequency laser light source 101, the spectroscope 102, the first analyzer 103, the second analyzer 108, the first photoelectric receiver 104 and the second photoelectric receiver 109 are all arranged on a base to form a laser head.
The working process of the device is as follows: the orthogonal polarized light emitted from the dual-frequency laser light source 101 passes through the beam splitter 102, and the incident light is split into two beams, one beam is used as reference light, and the other beam is used as measurement light. The reference light is synthesized by the first analyzer 103 and received and converted into an ac electric signal — a reference signal by the first photoelectric receiver 104. The measuring light passes through the first wollaston prism 105, is separated by a small angle, then passes through the second wollaston prism 106, is changed into two parallel beams, is reflected by the right-angle prism 107, then passes through the second wollaston prism 106 and the first wollaston prism 105 in sequence, is changed into a beam of light again, is synthesized by the second analyzer 108, and is received and converted into an alternating current signal-measuring signal by the second photoelectric receiver 109. The movement of the first wollaston prism 105 or the second wollaston prism 106 perpendicular to the optical path direction changes the phase of the measurement signal relative to the reference signal, the reference signal and the measurement signal are compared in phase by the phase meter 110, and the result is sent to the computer 111 for data processing, so that the movement amount of the first wollaston prism 105 or the second wollaston prism 106 can be obtained.
If the second wollaston prism 106 and the right-angle prism 107 are placed at one end of the guide rail and the laser head is placed at the other end, the light path is adjusted to be parallel to the guide rail, and the first wollaston prism 106 moves along the guide rail, so that the straightness deviation in the horizontal or vertical direction of the guide rail can be measured.
In roll angle measurement, there are measurement methods using an electronic level and measurement using a laser interferometer. The electronic level meter is used for measuring the roll angle, the electronic level meter is arranged on a platform to be measured, when the roll angle of the platform in the moving process changes, the relative angle between the reference plane of the electronic level meter and the horizontal plane of the earth changes, and the electronic level meter measures the changed angle value, namely the change of the roll angle of the platform in the moving process. The measuring method has two defects, namely, the measuring method can only carry out measurement in a horizontal plane, and when the platform moves along the plumb direction, an electronic level meter cannot be used for measurement; secondly, the measurement speed is low, the measurement can be carried out only when the platform is in a static state, and the real-time measurement can not be carried out in the moving process of the platform. The existing roll angle measuring method using the laser interferometer has the advantages of high precision, real-time measurement and the like, but generally has the defects of large number of optical elements, complex structure, sensitivity to temperature drift of an optical device and the like.
If two sets of the straightness measuring devices are used in parallel, the straightness and the roll angle can be measured simultaneously. The implementation device of the method is shown in fig. 2, and comprises: the double-frequency laser head 201, the neutral beam splitter prism 202, the reflecting mirror 211, the first Wollaston prism 203, the second Wollaston prism 204, the first right-angle prism 205 and the first polarized photoelectric receiver 206 which are arranged in the transmission light path of the neutral beam splitter prism 202, the third Wollaston prism 209, the fourth Wollaston prism 209, the second right-angle prism 207 and the second polarized photoelectric receiver 210 which are arranged in the reflection light path of the reflecting mirror 211, and a signal processing unit consisting of a phase meter 212 and a computer 213.
The dual-frequency laser head 201 can be understood as a combination of the dual-frequency laser light source 101, the beam splitter 102, the first analyzer 103 and the first photoelectric receiver 104 in fig. 1. The first polarization photoreceiver 206 and the second polarization photoreceiver 210 are both a photoreceiver with a built-in analyzer and a signal amplification circuit, that is, they are equivalent to a combination of an analyzer, a photoreceiver and a signal amplification circuit.
The working process of the device in fig. 2 is as follows: in the dual-frequency laser head 201, the orthogonal polarized light emitted from the dual-frequency laser light source passes through the spectroscope, the incident light is divided into two beams, one beam is used as reference light, the two beams are synthesized by the analyzer, the reference light is received and converted into an alternating current signal, namely a reference signal, by the photoelectric receiver, and the other beam is used as measurement light and emitted from the dual-frequency laser head 201. The measurement light is first split by the neutral beam splitter prism 202, the transmission light is used as the first measurement light, and the reflection light is reflected by the reflection mirror 211 and then used as the second measurement light. The first measuring light and the second measuring light respectively pass through two sets of identical straightness interference devices, and the working principle of the straightness interference devices is as described above. The second Wollaston prism 204, the fourth Wollaston prism 206, the first right-angle prism 205 and the second right-angle prism 207 are placed at one end of the guide rail, the double-frequency laser head 201 is placed at the other end of the guide rail, the light path is adjusted to enable the transmission light of the neutral beam splitter prism 202 and the reflection light of the reflector 211 to be parallel to the guide rail respectively, and the first Wollaston prism 203 and the third Wollaston prism 209 are fixed on the moving table together and move along the guide rail.
The first measurement light and the second measurement light return from the respective optical paths, and are received by the first polarization photoelectric receiver 206 and the second polarization photoelectric receiver 210, respectively, and are converted into a first measurement signal and a second measurement signal, respectively. The movement of the first wollaston prism 203 and the third wollaston prism 209 perpendicular to the optical path direction changes the phases of the first measurement signal and the second measurement signal relative to the reference signal, respectively, the reference signal and the two measurement signals are compared by the phase meter 212, and the result is sent to the computer 213 for data processing, so that the movement amounts of the first wollaston prism and the third wollaston prism can be obtained, and the calculation formula is as follows:
in the formula: s1，S2: a first linearity deviation and a second linearity deviation
λ: laser wavelength
θ: included angle between two emergent lights of Wollaston prism
C1，C2: first and second accumulated numbers of a phase counter
From these two values, the straightness of the guide rail and the roll angle of the mobile station during the movement can be measured, and the calculation formula is as follows:
in the formula: s: deviation of straightness of guide rail
α: roll angle of mobile station
D: spacing between first and second right angle prisms
This measurement method has the disadvantage that if the two rectangular prisms 205, 207 are not oriented exactly parallel to each other, a large roll angle measurement error results. As shown in fig. 3, point 1 is the starting position of the first wollaston prism 203, line 3 is the moving direction thereof, line 5 is the normal direction of the first rectangular prism 205, and the included angle 7 between the two lines is recorded as
Point 2 is the starting position of the third wollaston prism 209, line 4 is the moving direction, line 6 is the normal direction of the second rectangular prism 207, and the included angle 8 between the two lines is
Assuming that the moving distance is L, the rolling angle 9 generated during the moving process is set to α 0 without loss of generality, and the first linearity deviation and the second linearity deviation measured at this time are respectively:
substituting the previous formula, the roll angle 9 measured at this time is:
based on the foregoing assumptions, the actual roll angle is zero, so the value of α' is itself the roll angle error. Two conclusions can be drawn from this formula, if
In the formula, the two terms before and after the subtraction are equal in size, then α' is 0, that is, the measurement error is zero, in other words, as long as the two measuring lights are parallel to each other, the included angle between the two measuring lights and the guide rail is nonzero, and rolling is not caused when the two measuring lights are non-zeroA corner error; secondly if
Then the measured α' ≠ 0, there is a systematic error.
The magnitude of this error is estimated as follows: considering a common measurement parameter, without assuming that D is 50mm and L is 1000mm, considering the need of manual adjustment of the measurement light and the direction of the guide rail, the error is about 20 arc seconds, i.e. about 0.1mrad, and so there is
Substituting the above formula, α is 0.23 °, that is, the error is 0.23 °. The roll angle should generally be measured with an accuracy on the order of arc seconds, and such a large error is unacceptable in actual measurement. The reason for this error is that: in the straightness measurement, the normal direction of the right-angle prism forms a reference straight line, and the straightness is the position change of the center point of the Wollaston prism relative to the straight line; the rotation angle measurement is carried out by two sets of straightness measuring devices, a plane formed by two parallel normal lines forms a reference plane of a roll angle, and the roll angle is the angle change of a central connecting line of the two Wollaston prisms relative to the plane; if the reference straight lines of the two straightness accuracy are parallel, even if the reference straight lines are not parallel to the guide rail, the rolling angle error is not caused; if the reference straight lines of two straightness are not parallel, the plane formed by the two straight lines is deviated, and a systematic error is generated by the deviation.
In addition, the measurement according to the method is that two light paths are required to be respectively adjusted to be parallel to the guide rail, the whole device is large in size, multiple in optical parts, high in cost and complex in light path adjustment.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, provides the dual-frequency laser interferometer capable of simultaneously measuring the roll angle and the straightness, integrates optical devices of two measuring optical paths through a specific structure, not only reduces the number of optical parts, but also reduces the workload in the adjusting process by half, more importantly, the two straightness shares one reference straight line, so that the roll angle error caused by the unparallel of the first measuring light and the second measuring light can be eliminated, and the measuring precision is greatly improved.
The technical scheme of the invention is as follows:
a dual-frequency laser interferometer capable of simultaneously measuring a roll angle and straightness comprises a dual-frequency laser head, a neutral spectroscope, a first polarized photoelectric receiver, a second polarized photoelectric receiver and a signal processing unit, wherein a signal of a reference light path sent by the dual-frequency laser head is received by the signal processing unit to form a reference signal, a measurement light path sent by the dual-frequency laser head is provided with the neutral spectroscope, and the neutral spectroscope forms two measurement light paths after transmission and reflection On the contrary, be parallel to each other and an interval distance neutral beam splitter reflection or the second that the transmission formed measures the light path and has set gradually the plane mirror and first polarisation beam splitter, second polarisation beam splitter and benchmark speculum, second polarisation beam splitter, first polarisation beam splitter and second polarization photoelectric receiver still lie in proper order the second and measure the light path of light path from the light path of benchmark speculum reflection back return light, first polarization photoelectric receiver and second polarization photoelectric receiver all connect signal processing unit.
Furthermore, the dual-frequency laser interferometer further comprises a first total reflector and a second total reflector, a first measurement light path formed by transmission or reflection of the neutral beam splitter passes through the first total reflector and then sequentially enters the first polarization beam splitter, the second polarization beam splitter and the reference reflector, and the first total reflector is further arranged between the first polarization beam splitter and the first polarization photoelectric receiver on a light path of return light of the first measurement light path after being reflected from the reference reflector; and a second measurement light path formed by reflection or transmission of the neutral beam splitter passes through the second total reflector after passing through the plane reflector and then sequentially enters the first polarizing beam splitter, the second polarizing beam splitter and the reference reflector, and the second total reflector is also arranged between the first polarizing beam splitter and the second polarizing photoelectric receiver on a light path of return light of the second measurement light path after being reflected from the reference reflector.
Further, the beam splitting surface of the neutral spectroscope and the reflecting surface of the plane reflector are parallel to each other.
Further, the reference reflector is a translation reflector or a separation reflector, the translation reflector is a plane mirror structure which has a light path drift self-adaptive function in two mutually perpendicular directions, when incident light enters along the characteristic direction of the translation reflector, the distance between return light and the incident light after reflection of the translation reflector is constant, and the distance does not change along with translation of the incident light; the reference reflector is a separation reflector, the separation reflector is a device which is provided with a reflecting surface and two refracting surfaces, incident light and reflected light are separated from each other by a certain distance, when the incident light is incident along the characteristic direction of the separation reflector, the distance between the reflected light of the separation reflector and the incident light is constant, and the distance is not changed along with the translation of the incident light.
Furthermore, when the reference reflector is a translational reflector, the translational reflector comprises three reflecting surfaces, the normals of the three reflecting surfaces are coplanar in space, and the synthetic direction of the normals of the three reflecting surfaces is parallel to the incident light.
Further, the translating mirror comprises three additional planar mirrors; or the translating mirror comprises an additional plane mirror and a pentagonal prism.
Furthermore, each total reflection mirror adopts a pyramid prism, a hollow corner prism or a cat-eye reflector.
Further, the structure and parameters of the second polarizing beam splitter are identical to those of the first polarizing beam splitter.
Furthermore, each polarizing beam splitter adopts a Wollaston prism or a Rochon prism.
Furthermore, the signal processing unit comprises a phase meter and a computer, the first polarization photoelectric receiver and the second polarization photoelectric receiver are connected with the computer through the phase meter, and the phase meter compares the phases of the two measuring signals of the two measuring optical paths with the reference signal.
The invention has the following technical effects:
the invention relates to a dual-frequency laser interferometer capable of simultaneously measuring a roll angle and straightness, a measuring light path emitted by a dual-frequency laser head is transmitted and reflected by a neutral beam splitter to form two measuring light paths respectively, a plane reflector is arranged in one measuring light path to enable the measuring light path to be parallel to the other measuring light path after being bent, a first polarizing beam splitter, a second polarizing beam splitter and a reference reflector are arranged on the two parallel measuring light paths simultaneously, namely, the first measuring light and the second measuring light of the two measuring light paths jointly pass through the first polarizing beam splitter, the second polarizing beam splitter and the reference reflector, and return light reflected by the reference reflector jointly passes through the second polarizing beam splitter and the first polarizing beam splitter and then enters two polarizing photoelectric receivers respectively. According to the dual-frequency laser interferometer, a common neutral spectroscope and a plane mirror are arranged on a measuring light path, and one incident light beam is divided into two emergent light beams which are parallel to each other, wherein one beam of light is taken as first emergent light, and the other beam of light is taken as second emergent light; two bundles of emergent lights still keep parallel after passing through first polarisation beam splitter and second polarisation beam splitter jointly, return light after being reflected by benchmark speculum respectively is opposite with the incident light direction, parallel to each other, a section distance apart each other, loop through second polarisation beam splitter and first polarisation beam splitter again respectively and synthesize a bundle of light, form first measuring light and second measuring light, get into first polarization photoelectric receiver and second polarization photoelectric receiver respectively in order to form first measuring signal and second measuring signal respectively, carry out signal processing to two measuring signals and a reference signal received by the signal processing unit. The double-frequency laser interferometer obtains the straightness in the direction through the movement of the first polarization beam splitter/the second polarization beam splitter perpendicular to the direction of the optical path, and obtains the roll angle through the roll of the first polarization beam splitter/the second polarization beam splitter relative to the direction of the optical path. The first polarization beam splitter/the second polarization beam splitter move along the guide rail, and the straightness and the roll angle can be measured simultaneously. The included angle between the normal of the reference reflector and the straight line of the guide rail to be measured can not cause the measurement error of the roll angle. The double-frequency laser interferometer can simultaneously complete the measurement of the roll angle and the straightness, integrates the optical devices of two measuring light paths through a specific structure, reduces the number of optical parts, greatly reduces the volume of equipment, reduces the cost of the equipment, reduces the workload of the adjusting process by half, simplifies the adjusting process, shortens the adjusting time and improves the testing efficiency; more importantly, the two paths of straightness share one reference straight line, and the reference reflector is used as a measurement reference and is kept fixed in the measurement process, so that the roll angle error caused by the fact that the first measurement light and the second measurement light are not parallel can be eliminated, the stability of the measurement result is improved, the measurement error is reduced, and the measurement precision is guaranteed.
Drawings
Fig. 1 is a schematic structural diagram of a conventional dual-frequency laser straightness measuring device.
Fig. 2 is a schematic structural view of a conventional dual-frequency laser straightness measuring device for measuring a roll angle.
Fig. 3 is a diagram of an error analysis of roll angle measurement performed by the device of fig. 2.
FIG. 4 is a schematic diagram of a preferred structure of a dual-frequency laser interferometer capable of measuring both roll angle and linearity.
FIG. 5 is a schematic diagram of the principle of the roll angle and straightness measurement optical paths of the dual-frequency laser interferometer according to FIG. 4.
FIG. 6 is a schematic diagram of another preferred structure of the dual-frequency laser interferometer capable of measuring both roll angle and linearity.
Fig. 7a, 7b, 7c, 7d and 7e are schematic diagrams of preferred configurations of the reference mirror of the present invention.
Detailed Description
The present invention will be described with reference to the accompanying drawings.
Fig. 4 is a schematic diagram of a preferred structure of a dual-frequency laser interferometer capable of simultaneously measuring a roll angle and a linearity, which includes a dual-frequency laser head 401, a first polarized photoelectric receiver 402, a second polarized photoelectric receiver 403, a neutral beam splitter 404, a plane mirror 405, a first polarized beam splitter 406, a second polarized beam splitter 407, a reference mirror 408 and a signal processing unit, where the signal processing unit of the embodiment includes a phase meter 409 and a computer 410 connected to each other. The signal of the reference light path emitted by the dual-frequency laser head 401 is received by the phase meter 409 of the signal processing unit to form a reference signal, the optical path axis of the measurement light path emitted by the dual-frequency laser head 401 is provided with the neutral beam splitter 404, the neutral beam splitter 404 transmits and reflects to form two measurement light paths, respectively, the neutral beam splitter 404 transmits or reflects (in this embodiment, reflects) to form a first measurement light path and is provided with a first polarized beam splitter 406, a second polarized beam splitter 407 and a reference reflector 408 in sequence, the second polarized beam splitter 407, the first polarized beam splitter 406 and the first polarized light receiver 402 are further provided in sequence on the optical path of the return light of the first measurement light path after reflecting from the reference reflector 408, the return light after reflecting from the reference reflector 408 is opposite to the incident light incident along the characteristic direction of the reference reflector 408, is parallel to each other and is spaced apart, and a plane is provided in sequence on the second measurement light path formed by the neutral beam splitter 404 reflecting or transmitting (in this embodiment, transmitting) The device comprises a reflecting mirror 405, a first polarization beam splitter 406, a second polarization beam splitter 407 and a reference reflecting mirror 408, wherein the second polarization beam splitter 407, the first polarization beam splitter 406 and a second polarization photoelectric receiver 403 are further sequentially located on a light path of return light of a second measurement light path reflected from the reference reflecting mirror 408, and the first polarization photoelectric receiver 402 and the second polarization photoelectric receiver 403 are both connected with a phase meter 409.
The dual-frequency laser head 401 directly emits two linearly polarized lights with different frequencies and mutually orthogonal polarization directions, the optical frequencies of the two polarization components are stable, the dual-frequency laser head 401 simultaneously provides a reference signal, and the frequency of the signal is equal to the difference between the optical frequencies of the two polarization components. The structure and parameters of the first polarization beam splitter 406 are completely the same as those of the second polarization beam splitter 407, and these two polarization beam splitters may be wollaston prisms, or polarization beam splitters of other configurations, such as rochon prisms, and emit two orthogonal linearly polarized lights in incident light to different directions respectively. The two polarized photoelectric receivers 402 and 403 have the same structure, and both can be realized by an analyzer and a photoelectric receiver, and a received light beam enters the photoelectric receiver after passing through the analyzer. The dual-frequency laser head 401, the two polarized photoelectric receivers 402 and 403, the neutral beam splitter 404 and the plane mirror 405 can be all mounted on a base to form an integrated laser head. The second polarization beam splitter 407 and the reference mirror 408 are mounted on another base to constitute a reflection head. The first polarizing beamsplitter 406 is mounted on a base to form a measuring head.
The specific working process of the device of the invention shown in fig. 4 is as follows: the dual-frequency laser head 401 emits two orthogonal linearly polarized lights with different frequencies and provides a reference signal with a frequency equal to the difference between the two frequencies. The neutral beam splitter 404 splits the incident light into two beams, a reflected beam and a transmitted beam, each of which includes two orthogonal linearly polarized components, one of which serves as the first outgoing light. The plane mirror 405 reflects the other beam of light to form a second outgoing light parallel to the first outgoing light, and the two outgoing lights are separated by a distance. The first emergent light and the second emergent light sequentially pass through the first polarized beam splitter 406 and the second polarized beam splitter 407 and are respectively changed into two beams of parallel light, after being reflected by the reference reflector 408, the first emergent light and the second emergent light are opposite to the incident light, are parallel to each other and are separated by a certain distance, sequentially pass through the second polarized beam splitter 407 and the first polarized beam splitter 406 and respectively change into one beam of light, respectively become first measuring light and second measuring light, are respectively received by the first polarized photoelectric receiver 402 and the second polarized photoelectric receiver 403 and are respectively converted into alternating current signals, and a first measuring signal and a second measuring signal are formed.
The rolling of the first polarizing beam splitter 406 about the optical path direction causes the phase of the first measurement signal and the phase of the second measurement signal relative to the reference signal to change in opposite directions, and in addition, the phase change is not caused by the movement and angular shift of the polarizing beam splitter in the other two directions. The reference signal is compared with the first measurement signal and the second measurement signal by the phase meter 409, and the result is sent to the computer 410 for data processing, so as to obtain the roll amount of the first polarized beam splitter 406, i.e. the roll angle data of the measuring head.
A movement of the first polarizing beam splitter 406 parallel to the beam splitting plane and perpendicular to the direction of the optical path causes the same change in phase between the first measurement signal and the second measurement signal with respect to the reference signal, except that a movement and an angular shift of the polarizing beam splitter in the other two directions does not cause such a phase change. The reference signal is compared with the first and second measurement signals by the phase meter 409, and the result is sent to the computer 410 for data processing, so as to obtain the movement amount of the first polarizing beam splitter 406, i.e. the straightness data of the measuring head.
If the integrated laser head is placed at one end of a guide rail (not shown in the figure), the emergent light path is adjusted to be parallel to the guide rail, the reflection head is placed at the other end of the guide rail, the reflection light path is adjusted to be parallel to the guide rail, and the measurement head moves along the guide rail, the roll angle along the guide rail and the straightness deviation in the horizontal or vertical direction of the guide rail can be measured simultaneously.
A specific calculation process of the phase difference is described below with reference to fig. 5.
Fig. 5 is a schematic diagram of the principle of the roll angle and straightness measuring optical path of the device according to fig. 4, which includes a first polarizing beam splitter 501, a second polarizing beam splitter 502 and a reference mirror 503, wherein the upper half of the optical path is expanded in the y-z plane, and the lower half of the optical path is expanded in the x-z plane.
The incident light beam is two light beams which are parallel to each other, namely a first emergent light and a second emergent light from the neutral beam splitter 404 and the plane reflector 405, and two identical straightness measuring light paths are formed and respectively are a first straightness measuring light path (1) and a second straightness measuring light path (2), and the distance between the two light paths is a distance (3). The incident light beam of the first linear measurement light path (1) comprises two orthogonal linear polarization components with different frequencies, namely a light beam (4) and a light beam (5) which are respectively marked by line segments and circles, the two orthogonal linear polarization components sequentially pass through a first polarization beam splitter 501 and a second polarization beam splitter 502, the two polarization components are separated in parallel, then are reflected by a reference reflector 503, are opposite to the incident light direction, are mutually parallel and are separated by a distance, and sequentially pass through the second polarization beam splitter 502 and the first polarization beam splitter 501, the two polarization components are recombined to form a first measurement light beam, and the first polarization photoelectric receiver 402 converts the first measurement light beam into an alternating current signal to form a first measurement signal. The second straightness measuring optical path (2) is completely the same as the first straightness measuring optical path (1), the incident light beams respectively comprise two orthogonal linear polarization components with different frequencies, the two polarization components sequentially pass through the first polarization beam splitter 501 and the second polarization beam splitter 502, the two polarization components are separated in parallel, then are reflected by the reference reflector 503, are opposite to the incident light direction, are parallel to each other and are separated by a distance, and sequentially pass through the second polarization beam splitter 502 and the first polarization beam splitter 501, the two polarization components are recombined to form a second measuring light beam, and the second measuring light beam is converted into an alternating current signal by the second polarization photoelectric receiver 403 to form a second measuring signal.
When the movement amount of the measuring head composed of the first polarizing beam splitter 501 along the direction parallel to the beam splitting plane and perpendicular to the optical path is X, that is, the straightness deviation is X; when the rotation angle of the measurement head composed of the first polarizing beam splitter 501 with the optical path direction as the axis is R, that is, the roll angle is R. The calculation process is as follows:
in the plane of the first linear interferometry optical path, when the second polarizing beam splitter 502 and the reference mirror 503 are not moved and the moving amount of the first polarizing beam splitter 501 perpendicular to the optical path direction is X1When the light beam (4) passes through the polarization beam splitter each time, the optical path length of the beam as the extraordinary ray is increased by neX1tan beta, optical path length reduction n as ordinary rayoX1tan β, total (n)e-no)X1tan β, the total optical path change amount of which is 2 (n) because the light beam (4) passes through the first polarizing beam splitter 501 twicee-no)X1tan β. The path of the light beam (5) is the same as that of the light beam (4), the polarization direction of the light beam is vertical to that of the light beam (4), and the optical path change of the light beam is equal to that of the light beam (4)And the sign is opposite, so the total optical path variation is as follows: -2 (n)e-no)X1tan β. Therefore, the difference of the total optical path variation between the two beams is:
Δ1＝4(ne-no)X1tanβ
in the formula: x1: deviation from first linearity
Beta: vertex angle of polarizing beam splitter
ne、no: refractive index of extraordinary and ordinary rays
Similarly, in the plane of the second straightness interferometry optical path, when the second polarization beam splitter 502 and the reference mirror 503 are not moved and the amount of movement of the first polarization beam splitter 501 perpendicular to the optical path direction is X2The difference Δ of the total optical path change between the two polarization components2Comprises the following steps:
Δ2＝4(ne-no)X2tanβ
in the formula: x2: deviation of second straightness
The phase change of the two measurement signals is proportional to the difference between the respective total optical path variation amounts, which are respectively:
in the formula: x1、X2: first and second linearity deviations
λ: laser wavelength
Beta: vertex angle of polarizing beam splitter
ne、no: refractive index of extraordinary and ordinary rays
C1、C2: phase meter measurement of first and second measurement signals
The reference signal is compared with the first and second measurement signals by the phase meter 409 to obtain C1And C2。
When the second polarizing beam splitter 502 and the reference mirror 503 are not moved, the amount of movement of the center of the first polarizing beam splitter 501 in this direction is X, and the roll angle is R, the following relationship holds:
c is to be1And C2Substituting the two formulas for calculation, the calculation formulas of the linearity deviation and the roll angle are as follows:
in the formula: x: deviation of straightness
R: roll angle
D: the interval between the first and second linearity measurement light paths
λ: laser wavelength
Beta: vertex angle of polarizing beam splitter
ne、no: refractive index of extraordinary and ordinary rays
C1、C2: phase meter count value of first measurement signal and second measurement signal
FIG. 6 is another preferred structural diagram of the dual-frequency laser interferometer capable of measuring both roll angle and linearity of the present invention, which includes a dual-frequency laser head 601, a neutral beam splitter 602 disposed on the optical path axis of the light source emitting end of the dual-frequency laser head 601, a first total reflector 605 disposed in the reflection direction of the neutral beam splitter 602, a plane mirror 603 disposed in the transmission direction of the neutral beam splitter, a second total reflector 604 disposed in the reflection direction of the plane mirror 603, a first polarization beam splitter 606, a second polarization beam splitter 607 and a reference reflector 608 sequentially disposed on the reflection optical path (first reflection) of the first total reflector 605 and the second total reflector 604, a first polarization photoelectric receiver 610 disposed on the reflection optical path (second reflection) of the first total reflector 605 and a second polarization photoelectric receiver 609 disposed on the reflection optical path (second reflection) of the second total reflector 604, a phase meter 611 connected with the dual-frequency laser and the two photoelectric receivers, and a computer 612. Compared with the structure shown in fig. 4, the structure of the dual-frequency laser interferometer in this embodiment further employs a first total reflector 605 and a second total reflector 604, so that a first measurement light path formed by reflection of the neutral beam splitter 602 first passes through the first total reflector 605 and then sequentially enters the first polarization beam splitter 606, the second polarization beam splitter 607 and the reference reflector 608, and the first total reflector 605 is further disposed between the first polarization beam splitter 606 and the first polarization optical receiver 610 on a light path of return light of the first measurement light path after being reflected from the reference reflector 608; a second measurement light path formed by transmission of the neutral beam splitter 602 passes through the second total reflector 604 after passing through the plane mirror 603, and then sequentially enters the first polarized beam splitter 606, the second polarized beam splitter 607 and the reference reflector 608, and the second total reflector 604 is further disposed between the first polarized beam splitter 606 and the second polarized photoelectric receiver 609 on a light path of return light of the second measurement light path after being reflected from the reference reflector 608.
The dual-frequency laser head 601, the neutral beam splitter 602, the plane mirror 603, the second polarization beam splitter 607, the reference mirror 608 and the two polarization photoelectric receivers 609 and 610 are all arranged on a base to form an integrated laser head. The first polarizing beam splitter 606, the two total reflection mirrors 604 and 605 are mounted on a base to form a measuring head.
The specific working process is as follows: incident light from the dual-frequency laser head 601 is firstly projected onto the neutral beam splitter 602, and is divided into two beams, namely a reflection beam path and a transmission beam path, which are respectively used for a first linearity measuring optical path and a second linearity measuring optical path. The reflected light emitted from the neutral beam splitter 602 passes through the first total reflector 605, the first polarization beam splitter 606 and the second polarization beam splitter 607 in sequence, becomes two parallel beams, is reflected by the reference reflector 608, is opposite to the incident light in direction, is parallel to each other, is spaced apart from each other, passes through the second polarization beam splitter 607 and the first polarization beam splitter 606 in sequence, becomes one beam again, becomes a first measurement light, enters the first total reflector 605 again, is reflected again, is received by the first polarization photoelectric receiver 610, and is converted into an alternating current signal, so that a first measurement signal is formed. The transmitted light emitted from the neutral beam splitter 602 is reflected by the plane mirror 603, and then the reflected light passes through the second total reflector 604, the first polarized beam splitter 606 and the second polarized beam splitter 607 in sequence, becomes two parallel beams, is reflected by the reference reflector 608, is opposite to the incident light direction, is parallel to each other, is spaced at a distance from each other, passes through the second polarized beam splitter 607 and the first polarized beam splitter 606 in sequence, becomes a beam of light, becomes a second measurement light, enters the second total reflector 604 again, is reflected again, is received by the second polarized light receiver 609, and is converted into an alternating current signal, so as to form a second measurement signal.
The rolling of the measuring head about the direction of the light path causes the two measuring signals to change in phase with respect to the reference signal in an opposite manner, and in addition, the movement and angular offset of the measuring head in the other two directions do not cause such a change in phase. The reference signal is compared with the two measuring signals respectively by the phase meter 611, and the result is sent to the computer 612 for data processing, so that the roll angle data of the measuring head can be obtained.
The same phase change between the two measurement signals with respect to the reference signal occurs due to the movement of the measuring head in the direction perpendicular to the light path parallel to the beam splitting plane of the first polarizing beam splitter 606, and besides, the phase change is not caused by the movement and the angular offset of the measuring head in the other two directions. The reference signal is compared with the two measuring signals respectively by the phase meter 611, and the result is sent to the computer 612 for data processing, so that the straightness data of the measuring head can be obtained.
If the laser head is placed at one end of a guide rail (not shown in the figure), the emergent light path is adjusted to be parallel to the guide rail, and the measuring head moves along the guide rail, the roll angle along the guide rail direction and the straightness deviation in the horizontal or vertical direction of the guide rail can be measured simultaneously. Compared with the embodiment shown in the previous fig. 4, the embodiment shown in fig. 6 omits a reflection head, simplifies the overall structure of the dual-frequency laser interferometer, and reduces the workload of optical path adjustment.
As in the previous embodiment, the linearity deviation and roll angle are calculated as:
in the formula: x: deviation of straightness
R: roll angle
D: the interval between the first and second linearity measurement light paths
λ: laser wavelength
Beta: vertex angle of polarizing beam splitter
ne、no: refractive index of extraordinary and ordinary rays
C1、C2: phase meter count value of first measurement signal and second measurement signal
Specifically, the splitting surface of the neutral beam splitter adopted by the dual-frequency laser interferometer capable of simultaneously measuring the roll angle and the straightness is preferably parallel to the reflecting surface of the plane mirror. Each total reflector can adopt a pyramid prism, a hollow corner prism or a cat-eye reflector. The reference mirror can be a translation mirror or a separation mirror, as shown in fig. 7a-7e, a preferred structure is shown, wherein fig. 7a, 7b, 7c and 7d are schematic diagrams of preferred structures using the translation mirror, the translation mirror is a plane mirror structure having an optical path drift adaptive function in two directions perpendicular to each other, when incident light enters along a characteristic direction of the translation mirror, a distance between return light and the incident light after reflection of the translation mirror is constant, and the distance does not change along with translation of the incident light; specifically, the translating mirror may be a flat mirror structure having three or more effective reflecting surfaces of an odd number, that is, three or five or more effective reflecting surfaces, which are coplanar in space and have a normal combining direction parallel to the incident light, where the incident light is reflected in the translating mirror. Fig. 7a, 7b and 7c all include three plane mirrors or all have three reflecting surfaces, the normals of the three reflecting surfaces are coplanar in space, and the synthetic direction of the normals of the three reflecting surfaces is parallel to the incident light, i.e. the incident light is reflected three times and then emitted, the emitted light is opposite to the incident light direction, is parallel to each other and is shifted by a fixed distance, and the shifting mirror can be formed by combining a plurality of plane mirrors or a polyhedral prism coated with a reflecting film. In addition, the translation mirror may also be composed of a plane mirror and a pentagonal prism, and the incident light shown in fig. 7d is incident to the pentagonal prism first and then to the plane mirror. Of course, the combination of three reflecting surfaces is not limited, and a combination of more reflecting surfaces may be used. Fig. 7e is a schematic diagram of a preferred structure using a separating mirror, which is a device having one reflecting surface and two refracting surfaces and the incident light and the reflected light are separated from each other by a certain distance, when the incident light is incident along the characteristic direction of the separating mirror, the distance between the reflected light and the incident light after the separation mirror is reflected is constant, and the distance does not change with the translation of the incident light. The preferable structure of the reference reflector can meet the requirement that the incident light and the emergent light are separated from each other by a certain distance. In addition, in the beam splitting plane of the polarization beam splitter, namely the direction of the measured straightness, the comprehensive action of the reference reflector on the light beam is equivalent to that of a plane reflector, so that the interferometer has self-adaptability to the angle drift and the parallel drift of the output light beam of the integrated laser head, namely the angle drift and the parallel drift of the output light beam of the integrated laser do not cause measurement errors.
The method for measuring the roll angle and the straightness by adopting the device shown in figure 4 comprises the following steps:
1. a double-frequency laser head 401 is used as a light source, the laser head outputs two linearly polarized light beams with different frequencies, stable light frequency and mutual orthogonality, and simultaneously outputs a reference signal with the frequency equal to the difference of the two frequencies;
2. the orthogonal linear polarized light emitted from the light source is divided into two parts of reflected light and transmitted light after passing through a neutral beam splitter 404;
3. a first part of light (which may be reflected light or transmitted light) passes through a first polarization beam splitter 406, two polarization components of the first part of light are split into two beams of light with a small angle, the two beams of light pass through a second polarization beam splitter 407 and are converted into two parallel beams of light, after the two parallel beams of light are reflected by a reference reflector 408, the reflected light at the moment is still two parallel beams of light and is separated from incident light by a distance, the reflected light passes through the second polarization beam splitter 407 and the first polarization beam splitter 406 in sequence and is converted into one beam of light, and the beam of light is received by a first polarization photoelectric receiver 402 to form a first measurement signal;
4. a second part of light (which may be reflected light or transmitted light) is reflected by the plane mirror 405, passes through the first polarization beam splitter 406, two polarization components of the light are split into two beams of light with a small angle therebetween, and then passes through the second polarization beam splitter 407 to become two parallel beams, after the two parallel beams are reflected by the reference mirror 408, the reflected light at this time remains two parallel beams and is spaced from the incident light by a distance, and the reflected light passes through the second polarization beam splitter 407 and the first polarization beam splitter 406 in sequence and then becomes one beam of light, and is received by the second polarization photoelectric receiver 403 to form a second measurement signal;
5. sending the reference signal in the step 1, the first measurement signal in the step 3 and the second measurement signal in the step 4 to a phase meter 409 for phase comparison to obtain the phase change of the first measurement signal and the second measurement signal relative to the reference signal. When the first polarizing beam splitter 406 is moved in the splitting plane thereof perpendicularly to the optical path, the difference between the phase changes of the two reflects the amount of movement, i.e., the roll angle;
6. sending the reference signal in the step 1, the first measurement signal in the step 3 and the second measurement signal in the step 4 to a phase meter 409 for phase comparison to obtain the phase change of the first measurement signal and the second measurement signal relative to the reference signal. When the first polarizing beam splitter 406 is moved in its splitting plane perpendicular to the optical path, the average of the phase changes of the two reflects the amount of movement, i.e., the straightness deviation;
7. by performing the 5 th step and the 6 th step simultaneously, the roll angle and the straightness can be measured simultaneously.
The invention relates to a dual-frequency laser interferometer for simultaneously measuring a roll angle and straightness, wherein a neutral spectroscope is arranged on a measuring light path, and a plane reflector, a first polarizing beam splitter, a second polarizing beam splitter and a reference reflector are sequentially arranged on a transmission light path or a reflection light path of the neutral spectroscope; the optical path has good resistance to interference factors such as air disturbance, ambient temperature change and the like, measurement errors are not caused by angle change and position change in other directions of a measurement component in the moving process, a reference reflector serving as a linearity reference is kept fixed in the measurement process, and two optical paths share the same reference reflector serving as a reference, so that the system error of a roll angle is eliminated, the stability of a measurement result is improved, the measurement errors are reduced, and the measurement accuracy is ensured.
It should be noted that the above-mentioned embodiments enable a person skilled in the art to more fully understand the invention, without restricting it in any way. Therefore, although the present invention has been described in detail with reference to the drawings and examples, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention.
Claims (10)
1. A dual-frequency laser interferometer capable of simultaneously measuring a roll angle and straightness comprises a dual-frequency laser head, a neutral spectroscope, a first polarized photoelectric receiver, a second polarized photoelectric receiver and a signal processing unit, wherein a signal of a reference light path sent by the dual-frequency laser head is received by the signal processing unit to form a reference signal, the neutral spectroscope is arranged on a measurement light path sent by the dual-frequency laser head, the neutral spectroscope forms two measurement light paths after transmission and reflection, the dual-frequency laser interferometer is characterized in that a first polarized beam splitter, a second polarized beam splitter and a reference reflector are sequentially arranged on the first measurement light path formed by transmission or reflection of the neutral spectroscope, and the second polarized beam splitter, the first polarized beam splitter and the first polarized photoelectric receiver are also sequentially arranged on the light path of the return light of the first measurement light path after being reflected by the reference reflector, the return light after being reflected by the reference reflector is opposite to the incident light incident along the characteristic direction of the reference reflector, is parallel to the reference reflector and is spaced at a certain distance, the reference reflector is a translation reflector or a separation reflector, the translation reflector is a plane mirror structure which has a light path drift self-adaption function in two mutually perpendicular directions, and the separation reflector is a device which has a reflecting surface and two refracting surfaces and has a certain distance between the incident light and the reflected light; the neutral beam splitter is used for reflecting or transmitting a second measurement light path to form, and the neutral beam splitter is used for reflecting or transmitting the second measurement light path to form, and the neutral beam splitter is used for sequentially arranging a plane reflector and the first polarized beam splitter, the second polarized beam splitter and the reference reflector, the second polarized beam splitter, the first polarized beam splitter and the second polarized photoelectric receiver are also used for sequentially arranging a light path for the second measurement light path to return light after being reflected from the reference reflector, and the first polarized photoelectric receiver and the second polarized photoelectric receiver are both connected with a signal processing unit.
2. The dual-frequency laser interferometer according to claim 1, further comprising a first total reflection mirror and a second total reflection mirror, wherein the first measurement light path formed by transmission or reflection of the neutral beam splitter passes through the first total reflection mirror and then sequentially enters the first polarization beam splitter, the second polarization beam splitter and the reference reflection mirror, and the first total reflection mirror is further disposed between the first polarization beam splitter and the first polarization photoelectric receiver on the light path of the return light of the first measurement light path after reflection from the reference reflection mirror; and a second measurement light path formed by reflection or transmission of the neutral beam splitter passes through the second total reflector after passing through the plane reflector and then sequentially enters the first polarizing beam splitter, the second polarizing beam splitter and the reference reflector, and the second total reflector is also arranged between the first polarizing beam splitter and the second polarizing photoelectric receiver on a light path of return light of the second measurement light path after being reflected from the reference reflector.
3. The dual frequency laser interferometer of claim 1 or 2, wherein the splitting surface of the neutral beam splitter and the reflecting surface of the plane mirror are parallel to each other.
4. The dual-frequency laser interferometer of claim 3, wherein when the incident light is incident along a characteristic direction of the translating mirror, a distance between the return light after reflection by the translating mirror and the incident light is constant, the distance not changing with translation of the incident light; when the incident light is incident along the characteristic direction of the separation mirror, the distance between the return light reflected by the separation mirror and the incident light is constant, and the distance does not change along with the translation of the incident light.
5. The dual frequency laser interferometer of claim 4 wherein, when the reference mirror is a translating mirror, the translating mirror comprises three reflecting surfaces, the normals of the three reflecting surfaces are spatially coplanar and the resultant direction of the normals of the three reflecting surfaces is parallel to the incident light.
6. The dual frequency laser interferometer of claim 5, wherein the translating mirror comprises three additional planar mirrors; or the translating mirror comprises an additional plane mirror and a pentagonal prism.
7. The dual-frequency laser interferometer of claim 2, wherein each of the total reflection mirrors is a corner cube, a hollow corner cube or a cat-eye mirror.
8. The dual frequency laser interferometer of claim 1 or 2, wherein the second polarizing beamsplitter has exactly the same configuration and parameters as the first polarizing beamsplitter.
9. The dual-frequency laser interferometer of claim 8, wherein each of the polarizing beam splitters is a Wollaston prism or a Rochon prism.
10. The dual-frequency laser interferometer according to claim 1 or 2, wherein the signal processing unit comprises a phase meter and a computer, the first polarization photoelectric receiver and the second polarization photoelectric receiver are connected with the computer through the phase meter, and the phase meter simultaneously compares the two measurement signals of the two measurement optical paths with the reference signal in phase.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910728477.4A CN110514147B (en) | 2019-08-08 | 2019-08-08 | Double-frequency laser interferometer capable of simultaneously measuring roll angle and straightness |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910728477.4A CN110514147B (en) | 2019-08-08 | 2019-08-08 | Double-frequency laser interferometer capable of simultaneously measuring roll angle and straightness |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110514147A CN110514147A (en) | 2019-11-29 |
| CN110514147B true CN110514147B (en) | 2021-05-18 |
Family
ID=68625451
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910728477.4A Active CN110514147B (en) | 2019-08-08 | 2019-08-08 | Double-frequency laser interferometer capable of simultaneously measuring roll angle and straightness |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110514147B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112504154B (en) * | 2020-11-02 | 2022-06-03 | 南京信息工程大学滨江学院 | Large-size support structure deformation measuring device and measuring method based on optical path |
| CN113566745B (en) * | 2021-07-30 | 2024-02-20 | 上海无线电设备研究所 | High-precision roll angle measuring device and method based on laser collimation technology |
| CN114705228B (en) * | 2022-03-25 | 2024-03-08 | 北京无线电计量测试研究所 | Multi-beam parallel laser generation device, parallel collimation adjustment device and method |
| CN116661163B (en) * | 2023-07-28 | 2023-12-08 | 成都飞机工业（集团）有限责任公司 | Collimation device and method for laser interferometer |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1036292C (en) * | 1992-09-17 | 1997-10-29 | 清华大学 | Two-frequency laser collimation measuring method and interferometer |
| US5642195A (en) * | 1992-12-25 | 1997-06-24 | Drachev; Vladimir Prokopievich | Dispersion interferometer using orthogonally polarized waves |
| CN103308004B (en) * | 2013-06-09 | 2016-01-20 | 北京市普锐科创科技有限责任公司 | The measurement mechanism of a kind of laser linearity and displacement |
| CN104634283B (en) * | 2015-02-06 | 2017-05-03 | 浙江理工大学 | Laser heterodyne interference linearity measuring device and laser heterodyne interference linearity measuring method with six-degree-of-freedom detection |
| CN108489424A (en) * | 2018-04-13 | 2018-09-04 | 上海理工大学 | Laser interference system for roll angle and straight line degree measurement |
| CN109781034B (en) * | 2019-01-22 | 2020-11-10 | 上海理工大学 | Micro-roll angle and linearity synchronous high-precision measurement interferometer and measurement method |
-
2019
- 2019-08-08 CN CN201910728477.4A patent/CN110514147B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN110514147A (en) | 2019-11-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110514147B (en) | Double-frequency laser interferometer capable of simultaneously measuring roll angle and straightness | |
| US6806960B2 (en) | Compact beam re-tracing optics to eliminate beam walk-off in an interferometer | |
| CN108592800B (en) | A kind of laser heterodyne interference measuring device and method based on plane mirror reflection | |
| US7355719B2 (en) | Interferometer for measuring perpendicular translations | |
| US9036154B2 (en) | Four-axis four-subdividing interferometer | |
| CN103308004B (en) | The measurement mechanism of a kind of laser linearity and displacement | |
| WO2016123812A1 (en) | Laser heterodyne interference linearity measuring apparatus and method having six-degrees-of-freedom detection | |
| KR20070090033A (en) | Overlapping common-path interferometers for two-sided measurement | |
| US7158236B2 (en) | Heterodyne laser interferometer for measuring wafer stage translation | |
| US20060039007A1 (en) | Vibration-insensitive interferometer | |
| US9036155B2 (en) | Six-axis four-subdividing interferometer | |
| CN108645343A (en) | A kind of laser heterodyne interference measuring device and method based on prism of corner cube reflection | |
| CN106019259B (en) | Laser frequency discrimination device and frequency discrimination method based on Mach-Zehnder interferometer | |
| WO2022062967A1 (en) | Heterodyne grating interferometry system based on secondary diffraction | |
| CN101210803A (en) | Two-dimensional transversal zeeman double-frequency laser linearity/coaxiality measuring device | |
| US20090135430A1 (en) | Systems and Methods for Reducing Nonlinearity in an Interferometer | |
| US3612694A (en) | Arrangement for interferometric measurement of two lengths | |
| US8223342B2 (en) | Methods and systems for measuring target movement with an interferometer | |
| CN110966939B (en) | Interferometric measuring device, measuring method and photoetching equipment | |
| EP0461773A2 (en) | Linear pitch, and yaw displacement measuring interferometer | |
| US3419331A (en) | Single and double beam interferometer means | |
| CN205899008U (en) | Laser mirror is device frequently based on mach is virtue interferometer once | |
| JPH09318311A (en) | Interferometer system | |
| JPH11108614A (en) | Light-wave interference measuring instrument | |
| JPS59136604A (en) | Multiple optical path laser interferometer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |