CN104596424B - A kind of two-dimensional displacement measurer of use double-frequency laser and diffraction grating - Google Patents
A kind of two-dimensional displacement measurer of use double-frequency laser and diffraction grating Download PDFInfo
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Abstract
The two-dimensional displacement measurer of a kind of use double-frequency laser and diffraction grating is related to a kind of ultraprecise displacement measuring technology and grating displacement measuring system, it is made up of scale grating and read head two parts, read head includes dual-frequency laser source, Z-direction interference part, scanning spectro-grating part, X to exploring block, Z-direction exploring block, Signal Processing Element；The device is based on Michelson's interferometer principle, many diffraction grating principle of interferences and optical beat principle, achievable X to while Z-direction displacement measure, have the advantages that compact conformation, strong antijamming capability, to after scale grating to Zero-order diffractive intensity requirement is low and X to and Z-direction measurement do not couple, a nanometer even more high measurement resolution can be realized, the high-precision displacement measurement of multiple degrees of freedom is can be applicable to.
Description
Technical field
The present invention relates to a kind of ultraprecise displacement measuring technology and grating displacement measuring system, more particularly to a kind of using double
The two-dimensional displacement measurer of frequency laser and diffraction grating.
Background technology
In recent years, ultra precise measurement has become the study hotspot of world's fields of measurement.In view of measurement range, precision, it is
The impact of the system factor such as size and working environment, realizes high-acruracy survey in the modern times with the multivariant measuring method of small size
Demand in displacement measurement is also increasingly projected.The positioning of mask stage and work stage in field of semiconductor processing, litho machine
Precision and kinematic accuracy are to limit the principal element that semiconductor chip processes live width, in order to ensure the positioning of mask stage and work stage
Precision and kinematic accuracy, generally adopting in litho machine is carried out with high accuracy, the two-frequency laser interferometer measuring system of wide range
Displacement measurement.The live width of existing semiconductor chip has approached 14nm in the market, and the semiconductor machining of continuous improvement will
Ask and bigger challenge is proposed to ultraprecise displacement measuring technology, and two-frequency laser interferometer measuring system is surveyed due to its long light path
Amount is easily affected by environment, and there is a series of problems, such as system bulk is big, price is high, it is difficult to meet new measurement demand.
For the problems referred to above, each major company and research institution in domestic and international ultra precise measurement field have all put into great effort
Studied, one of main direction of studying includes researching and developing the new displacement measurement system based on diffraction grating.Based on diffraction
Development of the displacement measurement system of grating through many decades, existing more achievement in research, has in many patents and paper
Disclose.
Patent US4776701 (publication date on October 11st, 1988) of German HEIDENHAIN companies is proposed and utilizes light beam
The method that X-direction displacement is measured by way of coherent superposition and optics phase shift are realized after reflecting grating and reflecting grating.Should
Method realizes interference signal phase shift using the structural parameters adjustment of grating itself, while measurement result does not receive Y-direction and Z-direction
The impact of displacement.As the method is not required to extra phase shifting component, therefore system bulk is less, but the method is only used for X
The displacement measurement in direction.
Patent US7362446B2 (publication date on April 22nd, 2008) of Dutch ASML companies proposes one kind and utilizes grating
Diffraction encoder and interferometer principle surveyors' staff grating, should using 3 in X-direction and the location measurement unit of Z-direction displacement
Location measurement unit can be while 6 degree of freedom of measuring table；Designed by special prism structure so that the position measurement
The optical element combinations such as other light splitting of unit in addition to scale grating, phase shift, closing light reach mitigation unit into an entirety
Size and quality, the purpose of compact conformation；Location measurement unit surveyors' staff grating X is encoded to displacement using optical grating diffraction
Diffraction light of the measurement light of device from scale grating, the measurement light of the used interferometer of surveyors' staff grating Z-direction displacement also from
The diffraction light of scale grating, but from the diffraction of different light beams, be discrete.The method can realize X to the position with Z-direction simultaneously
Shift measurement, but interferometer is different with the position that optical grating diffraction is measured, and prism group structure is more complicated.
Japanese scholars Wei Gao and Tsing-Hua University scholar Zeng Lijiang et al. combine paper " the Design and for delivering
construction of a two-degree-of-freedom linear encoder for nanometric
measurement of stage position and straightness.Precision Engineering34(2010)
A kind of two-dimensional grating measurement apparatus of utilization diffraction grating principle of interference are proposed in 145-155 ".The laser Jing of laser emitting
Cross polarization splitting prism and be divided into measurement light and reference light, the two incides scale grating respectively and concurrently life is reversely spread out with reference to grating
Penetrate, reverse diffraction light incides photoelectric detection unit after converging at polarization splitting prism and interferes, and is moved using subsequent optical path
Phase, can receive interference signal in four groups of detector surfaces.By processing to interference signal, the reading of decoupling grating can be solved
Several relative to scale grating in X to the displacement information with Z-direction both direction.The method is drawn to realize the phase shift to signal
Many phase shift optics are entered, volume is larger；And when the Z-direction that read head and grating are produced is moved, interference region
Scope diminishes, and is unfavorable for the measurement of the larger range of Z-direction.
Patent CN102937411A (publication date on 2 20th, 2013) of Tsing-Hua University scholar Zhu Yu and CN102944176A
In (publication date on 2 27th, 2013), it is proposed that the two-dimensional grating measuring system designed using diffraction grating principle of interference, and draw
Enter double-frequency laser and generated beat signal, enhance the capacity of resisting disturbance of measurement signal.This group of patent when read head relative to
When scale grating occurs Z-direction motion, interference region scope diminishes, and is unfavorable for the measurement of the larger range of Z-direction.
Rich patent CN102865817A of Amada Co., Ltd. three (publication date on January 9th, 2013) and US8604413B2
(publication date on December 10th, 2013) proposes a kind of construction of two-dimension displacement sensor, and this is configured to realize that multi-dimensional displacement is surveyed
Amount, but whole system adopts transmission mode, and has used the optics such as prism for refractive power, therefore system bulk compared with
Greatly.
Patent CN103604376A (publication date on 2 26th, 2014) of Harbin Institute of Technology's scholar's Hu Pengcheng et al.
In, it is proposed that a kind of anti-light grating interference instrument system for learning frequency alias, by the double-frequency laser of laser emitting spatially
Separately the setting of transmission, eliminates optical frequency aliasing and corresponding cycle nonlinearity erron, and can realize three-D displacement
Measurement；In patent CN103644849A (publication date on March 19th, 2014) of Harbin Institute of Technology scholar Lin Jie et al., pass through
Introduce auto-collimation principle and propose a kind of three-D displacement measuring system, the system can realize the Z-direction displacement measurement of larger range,
But as light beam light splitting number of times is more, it is unfavorable for improving the quality of interference signal.
The content of the invention
To solve the limitation of such scheme, aforesaid measurement requirement is adapted to and meets, the present invention is using typical Michael
Inferior principle of interference, many diffraction grating principle of interferences and optical beat principle, devise a kind of simple and compact for structure, small volume, resist
The two-dimensional displacement measurer of the strong use double-frequency laser of interference performance and diffraction grating.When the read head of this device is relative to mark
During the displacement of chi grating occurred level direction (X to) and vertical direction (Z-direction), it is capable of achieving high-precision two-dimension displacement and surveys in real time
Amount.
Technical scheme is as follows：
The two-dimensional displacement measurer of a kind of use double-frequency laser and diffraction grating, including scale grating and read head, read
Several include dual-frequency laser source, Z-direction interference part, scanning spectro-grating part, X to exploring block, Z-direction exploring block, letter
Number processing component；Dual-frequency laser source includes two-frequency laser, Amici prism, polaroid A；Z-direction interference part includes polarization point
Light prism, quarter wave plate A, reflection part, quarter wave plate B, polaroid B；Scanning spectro-grating part includes scanning spectro-grating, light
Door screen；The grid line place plane of scanning spectro-grating is parallel with the grid line place plane of scale grating；Scanning spectro-grating is one-dimensional
Grating, scale grating have backward zero order diffracted light, and scan spectro-grating and scale grating equivalent grating week in the X direction
Phase is equal；X-direction be with scanning spectro-grating grid line place plane it is parallel, and perpendicular to scanning spectro-grating grid line side
To；Z-direction is the direction vertical with the grid line place plane of scanning spectro-grating；Equivalent screen periods refer to grating in one party
Cycle upwards；The double frequency crossed polarized light of two-frequency laser outgoing incides Amici prism, and its reflected light is through after polaroid A
Incide Z-direction exploring block, the reference signal all the way that the beat signal of formation is measured as Z-direction, its transmitted light incide polarization
It is divided into reference light and measurement light after Amici prism；Reference light passes through quarter wave plate A, and after being reflected by reflection part, successively through 1/
4 wave plate A, polarization splitting prism, polaroid B incide Z-direction exploring block；Measurement light transmission quarter wave plate B tailing edge Z-direction is incident
To scanning spectro-grating, after scanned spectro-grating diffraction, diffracted beam incides scale grating and concurrently gives birth to reverse diffraction, reversely
Diffraction light obtains nine beam measuring beams and other spuious light beams through scanning spectro-grating diffraction light splitting；In nine beam measuring beams,
The direction of propagation is identical two-by-two for wherein eight beams, incides X and forms four groups of interference signals to exploring block, by signal processing unit solution
Obtain after calculation read head relative to scale grating X to occur displacement；Another in nine beam measuring beams is returned along incident direction
The measuring beam for returning passes through quarter wave plate B, and incides Z-direction exploring block through polaroid B after being reflected by polarization splitting prism；
The reference light and measurement light for inciding Z-direction exploring block meets the measurement signal all the way that the beat signal to be formed measured as Z-direction,
The reference signal and measurement signal of Z-direction measurement obtains read head relative to scale grating in Z after signal processing unit resolving
To the displacement for occurring.
When scanning spectro-grating is one-dimensional rectangular raster, scale grating includes following structure arrangement mode：1. scale grating
For one-dimensional rectangular raster, and its grid line direction is parallel with the grid line direction of scanning spectro-grating；2. scale grating is two-dimensional rectangle
Grating, and two grid line direction is parallel and vertical with the grid line direction of scanning spectro-grating respectively；3. scale grating is two dimension
Rectangular raster, and two grid line direction is at 45 ° with the grid line direction of scanning spectro-grating respectively.
Diaphragm is additionally arranged in scanning spectro-grating part, and diaphragm is located at scanning spectro-grating with X to exploring block
Between.
When two-frequency laser outgoing is through the wavelength X=632.8nm of measurement light of spectro-grating is scanned, 1. scanning point
Light grating adopts one group of preferred parameter of one-dimensional rectangular raster for d=10 μm of screen periods, grating steps height h=488nm, light
Grid step width a=3.567 μm；2. the parameter of scale grating includes：A () adopts one-dimensional rectangular raster, and its when scale grating
When grid line direction is parallel with the grid line direction of scanning spectro-grating, one group preferred parameter is d=10 μm of screen periods, grating platform
Rank height h=488nm, a=3.567 μm of grating steps width；B () adopts two-dimensional rectangle grating, and two when scale grating
When grid line direction is parallel and vertical with the grid line direction of scanning spectro-grating respectively, one group preferred parameter is two grid line directions
Screen periods d1=d2=10 μm, grating steps height h=159nm, the grating steps width a in two grid line directions1=a2=
5.67μm；C () adopts two-dimensional rectangle grating, and two grid line direction grid line respectively with scanning spectro-grating when scale grating
When direction is at 45 °, one group preferred parameter is the screen periods d in two grid line directions1=d2=7.07 μm, grating steps height h
=159nm, two grid line direction grating steps width a1=a2=4.01 μm.
The present invention is carried using typical Michelson's interferometer principle, many diffraction grating principle of interferences and optical beat principle
A kind of use double-frequency laser for going out and the two-dimensional displacement measurer of diffraction grating, with following novelty and prominent effect：
1., by scale grating and scanning spectro-grating are placed in parallel, and the two is in the equivalent screen periods of X-direction
Equal, scale grating has the setting of backward zero order diffracted light, can provide measurement signal to Z-direction for X simultaneously, and then while survey
Amount read head in the displacement of X, Z both direction, and realizes optics 2 and segments relative to scale grating, and the electricity of appropriate mix is thin
Divide card, it is possible to achieve nanometer accuracy measurement.
2.Z adopts the optical beat principle of double-frequency laser to measurement, to dropping to Zero-order diffractive intensity requirement after scale grating
It is low, the power requirement to laser instrument is reduced, while also enhancing the capacity of resisting disturbance of signal, Z-direction high-acruracy survey is capable of achieving.
3. as the displacement measurement of X-direction make use of scanning spectro-grating and the scale grating dichroism of itself to realize phase
Dry superposition and optics phase shift, therefore extra phase shift optics are not needed, physical dimension had both been reduced, phase shift conjunction had been turn avoid
The error that optical device brings.
4., by scale grating and scanning spectro-grating are placed in parallel, and the two is in the equivalent screen periods of X-direction
Equal setting, can cause read head relative to scale grating when Z-direction is moved, and not affect X to the scope of measurement interference region,
So larger Z-direction measurement range can be provided.
5., when displacement is detected, X simplifies follow-up letter to there is no coupled relation between the measurement signal of Z-direction
Number processing mode, reduces the error of signal processing introducing.
6.X can further be reduced the volume of read head, particularly be set to being derived by optical fiber with Z-direction measurement signal
When the cycle of photometric grid is micron dimension, the two-dimensional displacement measurer simultaneously have compact conformation, small volume, light weight it is excellent
Point, it is convenient to apply.
Description of the drawings
Fig. 1 is a kind of structural representation of the two-dimensional displacement measurer of use double-frequency laser and diffraction grating of the present invention
Figure.
Fig. 2 a are the present invention scanning spectro-grating placement schematic diagram parallel and vertical with scale grating grid direction.
Fig. 2 b are present invention scanning spectro-grating and scale grating grid direction placement schematic diagram at 45 °.
Fig. 3 a are the structural representation of the one-dimensional rectangular raster of present invention application.
Fig. 3 b are the structural representation of the two-dimensional rectangle grating of present invention application.
Fig. 4 is a kind of light path of the two-dimensional displacement measurer embodiment of use double-frequency laser and diffraction grating of the present invention
Transmission direction schematic diagram.
Piece number explanation in figure：1- dual-frequency laser sources, 2-Z is to interference part, 3- scanning spectro-grating parts, 4- scale lights
Grid, to exploring block, 6-Z is to exploring block, 7- Signal Processing Elements for 5-X；11- two-frequency lasers, 12- Amici prisms, 13- are inclined
Shake piece A；21- polarization splitting prisms, 22-1/4 wave plate A, 23- reflection parts, 24-1/4 wave plate B, 25- polaroid B；31- is scanned
Spectro-grating, 32- diaphragms.
Specific embodiment
Below in conjunction with the accompanying drawings the specific embodiment of the present invention is further described in detail.
The two-dimensional displacement measurer of a kind of use double-frequency laser and diffraction grating, including scale grating 4 and read head, read
Several include dual-frequency laser source 1, Z-direction interference part 2, scanning spectro-grating part 3, X to exploring block 5, Z-direction exploring block
6th, Signal Processing Element 7；Dual-frequency laser source 1 includes two-frequency laser 11, Amici prism 12, polaroid A 13；Z-direction interference part
Part 2 includes polarization splitting prism 21, quarter wave plate A22, reflection part 23, quarter wave plate B24, polaroid B25；Scanning spectro-grating
Part 3 includes scanning spectro-grating 31, diaphragm 32；The grid line of the grid line place plane and scale grating 4 of scanning spectro-grating 31
Place plane is parallel；Scanning spectro-grating 31 is one-dimensional grating, and scale grating 4 has backward zero order diffracted light, and scans light splitting
Grating 31 and scale grating 4 equivalent screen periods in the X direction are equal；X-direction is the grid line institute with scanning spectro-grating 31
It is parallel in plane, and perpendicular to the direction of scanning 31 grid line of spectro-grating；Z-direction is the grid line place with scanning spectro-grating 31
The vertical direction of plane；Equivalent screen periods refer to the grating cycle in one direction；The double frequency of 11 outgoing of two-frequency laser
Crossed polarized light incides Amici prism 12, and its reflected light is through inciding Z-direction exploring block 6, the bat of formation after polaroid A 13
The reference signal all the way that frequency signal is measured as Z-direction, its transmitted light are divided into reference light and survey after inciding polarization splitting prism 21
Amount light；Reference light passes through quarter wave plate A22, and after being reflected by reflection part 23, successively through quarter wave plate A22, polarization spectro rib
Mirror 21, polaroid B25 incide Z-direction exploring block 6；Measurement light transmission quarter wave plate B24 tailing edge Z-directions incide scanning light splitting
Grating 31, after 31 diffraction of scanned spectro-grating, diffracted beam incides scale grating 4 and reverse diffraction occurs, reverse diffraction light
Through scanning 31 diffraction light splitting of spectro-grating, nine beam measuring beams and other spuious light beams are obtained；In nine beam measuring beams, wherein
The direction of propagation is identical two-by-two for eight beams, incides X and forms four groups of interference signals to exploring block 5, is resolved by signal processing unit 7
Obtain afterwards read head relative to scale grating 4 X to occur displacement；It is another along incident direction return in nine beam measuring beams
Measuring beam pass through quarter wave plate B24, and incide Z-direction probe portion through polaroid B25 after being reflected by polarization splitting prism 21
Part 6；The reference light and measurement light for inciding Z-direction exploring block 6 meets the measurement all the way that the beat signal to be formed measured as Z-direction
Signal, the reference signal and measurement signal of Z-direction measurement obtain read head relative to scale light after the resolving of signal processing unit 7
The displacement that grid 4 occur in Z-direction.
The two-dimensional displacement measurer of a kind of use double-frequency laser and diffraction grating of the present invention, scanning spectro-grating 31 is
During one-dimensional rectangular raster, its scale grating 4 includes following structure arrangement mode：1. scale grating 4 is one-dimensional rectangular raster, and its
Grid line direction is parallel with the grid line direction of scanning spectro-grating 31；2. scale grating 4 is two-dimensional rectangle grating, and two grid line
Direction is parallel and vertical with the grid line direction of scanning spectro-grating 31 respectively；3. scale grating 4 be two-dimensional rectangle grating, and its two
Individual grid line direction is at 45 ° with the grid line direction of scanning spectro-grating 31 respectively.
The two-dimensional displacement measurer of a kind of use double-frequency laser and diffraction grating of the present invention, in scanning spectro-grating portion
Diaphragm 32 is additionally arranged in part 3, and diaphragm 32 is located at scanning spectro-grating 31 and X between exploring block 5.
The two-dimensional displacement measurer of a kind of use double-frequency laser and diffraction grating of the present invention, goes out in two-frequency laser 11
When that what is penetrated passes through the wavelength X=632.8nm of measurement light of scanning spectro-grating 31,1. scan spectro-grating 31 one group is preferably joined
Number is d=10 μm of screen periods, grating steps height h=488nm, a=3.567 μm of grating steps width；2. scale grating 4
Parameter includes：A () adopts one-dimensional rectangular raster, and its grid line direction and the grid line side for scanning spectro-grating 31 when scale grating 4
To it is parallel when, one group preferred parameter be d=10 μm of screen periods, grating steps height h=488nm, grating steps width a=
3.567μm；B () adopts two-dimensional rectangle grating when scale grating 4, and two grid line direction respectively with scanning spectro-grating 31
When grid line direction is parallel and vertical, one group preferred parameter is the screen periods d in two grid line directions1=d2=10 μm, grating platform
Rank height h=159nm, the grating steps width a in two grid line directions1=a2=5.67 μm；C () is when scale grating 4 is using two dimension
Rectangular raster, and two grid line direction respectively with scanning spectro-grating 31 grid line direction it is at 45 ° when, one group preferred parameter
For the screen periods d in two grid line directions1=d2=7.1 μm, grating steps height h=159nm, two grid line direction grating platforms
Rank width a1=a2=4.01 μm.
So that scale grating 4 and scanning spectro-grating 31 are one-dimensional rectangular raster as an example, one kind of the present invention uses double frequency
The two-dimensional displacement measurer of laser and diffraction grating in the specific implementation, as shown in Figure 4, the bag of 11 outgoing of two-frequency laser
Containing wavelength X1And λ2After double frequency crossed polarized light OP incides Amici prism 12, its reflected light is through inciding Z after polaroid A 13
To exploring block 6, the reference signal all the way that the beat signal of formation is measured as Z-direction, its transmitted light OP1 incide polarization spectro
On prism 21, polarization splitting prism 21 is arranged so that light beam OP1 is divided into direction of vibration and puts down after inciding polarization splitting prism 21
Row is in X-Z plane (p ripples) and wavelength is λ1Measurement light OP2-2 and direction of vibration perpendicular to X-Z plane (s ripples) and wavelength be λ2
Reference light OP2-1.
Measurement light OP2-2 occur after inciding scanning spectro-grating 31 through quarter wave plate B24 diffraction produce -1 grade of OP3-1,
0 grade of OP3-2 ,+1 grade of OP3-3 three beams measuring beam；There is reverse diffraction after inciding scale grating 4 in the three beams measuring beam, obtain
To five beam measuring beam [- 1 ,+1] levels OP3-13, [0, -1] level OP3-21, [0,0] level OP3-22, [0 ,+1] level OP3-23, [+
1, -1] level OP3-31 and other spuious light beams；The five beams measuring beam spreads out after inciding scanning spectro-grating 31 again
Penetrate, the spuious light beam of its diffraction light is arranged on scanning spectro-grating 31 and X is blocked to the diaphragm 32 between exploring block 5, not
The measuring beam being blocked have [- 1 ,+1, -1] level OP3-131, [0, -1,0] level OP3-212, [- 1 ,+1,0] level OP3-132,
[0, -1 ,+1] level OP3-213, [+1, -1,0] level OP3-312, [0 ,+1, -1] level OP3-231, [+1, -1 ,+1] level OP3-313,
[0 ,+1,0] level OP3-232 and [0,0,0] level OP3-222 totally nine beam.
[- 1 ,+1, -1] level OP3-131 in nine beam measuring beams and [0, -1,0] level OP3-212, [- 1 ,+1,0] level
OP3-132 and [0, -1 ,+1] level OP3-213, [+1, -1,0] level OP3-312 and [0 ,+1, -1] level OP3-231, [+1, -1 ,+1]
The direction of propagation is identical two-by-two with [0 ,+1,0] level OP3-232 for level OP3-313, incides X and forms four groups of interference letters to exploring block 5
Number, and the change of four groups of interference signals is only relevant to the displacement for occurring in X relative to scale grating 4 with read head, and this four
Group interference signal is processed by signal processing unit 7 after being received to exploring block 5 by X and obtains the mutually orthogonal electricity letter of two-way
Number, obtain after resolving read head relative to scale grating 4 X to occur displacement.
It is 45 ° that the modes of emplacement of quarter wave plate A22 may be configured as quick shaft direction with X-Z plane angle, and reference light OP2-1 is saturating
Quarter wave plate A22 being crossed, and quarter wave plate A22 being again passed through after being reflected by reflection part 23, its polarization direction is rotated by 90 ° and incident
There is transmission on polarization splitting prism 21, Z-direction spy is incided through the reference light that Z-direction measurement is eventually served as after polaroid B25
Survey part 6；It is 45 ° that the modes of emplacement of quarter wave plate B24 may be configured as quick shaft direction with X-Z plane angle, and light OP2-2 is saturating for measurement
Quarter wave plate B24, scanning spectro-grating 31 are crossed, and is reflected by scale grating 4, be again passed through scanning spectro-grating 31, as nine beams
Measuring beam [0,0,0] level OP3-222 returned along incident direction in measurement light, which is again passed through quarter wave plate B24 rear polarizer sides
Reflection occur on polarization splitting prism 21 to being rotated by 90 ° and being incided, through the survey that Z-direction measurement is eventually served as after polaroid B25
Amount light incides Z-direction exploring block 6；The meet beat signal to be formed of reference light and measurement light for inciding Z-direction exploring block 6 is made
Only occur in Z-direction relative to scale grating 4 comprising read head for the measurement signal all the way of Z-direction measurement, and the beat signal
Displacement information；The reference signal and measurement signal of the Z-direction measurement received by Z-direction exploring block 6 is resolved by signal processing unit 7
The displacement that read head occurs in Z-direction relative to scale grating 4 is obtained afterwards.
In order to improve the quality of the beat signal that Z-direction exploring block 6 is received, it is required that inciding Z-direction exploring block 6
Measurement light and reference light energy approximation it is equal, therefore in the specific implementation, reflection part 23 is set to part reflector part, makes
The measurement light that receives of Z-direction exploring block 6 and reference light energy approximation it is equal.
In specific implementation process, in order to further reduce read head volume, Amici prism 12, polaroid A 13, polarization spectro
Prism 21, quarter wave plate A22, quarter wave plate B24, reflection part 23, polaroid B25, integral structure can be adopted.
In specific implementation process, in order to reduce read head volume, while weakening the radiating of two-frequency laser 11 to detector
Impact, it is possible to use optical fiber is by the beam Propagation of 11 outgoing of two-frequency laser to light path.
With reference to Fig. 2 a, it is the present invention scanning spectro-grating 31 placement side parallel and vertical with 4 grid line direction of scale grating
Formula schematic diagram, wherein scanning spectro-grating 31 is one-dimensional rectangular raster, scale grating 4 is two-dimensional rectangle grating, scans light splitting light
Grid 31 are placed in parallel with scale grating 4, two grid line directions of scale grating 4 grid line direction respectively with scanning spectro-grating 31
It is parallel and vertical.
With reference to Fig. 2 b, it is that present invention scanning spectro-grating 31 modes of emplacement at 45 ° with 4 grid line direction of scale grating is illustrated
Figure, wherein scanning spectro-grating 31 is one-dimensional rectangular raster, scale grating 4 is two-dimensional rectangle grating, scanning spectro-grating 31 with
Scale grating 4 is placed in parallel, and two grid line directions of scale grating 4 are at 45 ° with the grid line direction of scanning spectro-grating 31 respectively.
With reference to Fig. 3 a, it is the one-dimensional rectangular raster structural representation of present invention application, wherein each parameter is：Screen periods d,
Grating steps height h, grating steps width a.
With reference to Fig. 3 b, it is the two-dimensional rectangle optical grating construction schematic diagram of present invention application, wherein each parameter is：Both direction light
Grid cycle d1And d2, grating steps height h, both direction grating steps width a1And a2。
Claims (4)
1. the two-dimensional displacement measurer of a kind of use double-frequency laser and diffraction grating, including scale grating (4) and read head, its
It is characterised by：Described read head includes dual-frequency laser source (1), Z-direction interference part (2), scanning spectro-grating part (3), X
To exploring block (5), Z-direction exploring block (6), Signal Processing Element (7)；Described dual-frequency laser source (1) is swashed including double frequency
Light device (11), Amici prism (12), polaroid A (13)；Described Z-direction interference part (2) including polarization splitting prism (21), 1/
4 wave plate A (22), reflection part (23), quarter wave plate B (24), polaroid B (25)；Described scanning spectro-grating part (3) bag
Include scanning spectro-grating (31), diaphragm (32)；The grid line place plane and scale grating (4) of described scanning spectro-grating (31)
Grid line place plane it is parallel；Described scanning spectro-grating (31) is one-dimensional grating, and scale grating (4) spreads out with backward zero level
Light is penetrated, and scanning spectro-grating (31) and scale grating (4) equivalent screen periods in the X direction are equal；Described X-direction is
It is parallel with the grid line place plane of scanning spectro-grating (31), and perpendicular to the direction of scanning spectro-grating (31) grid line；Z-direction
It is the direction vertical with the grid line place plane of scanning spectro-grating (31)；Described equivalent screen periods refer to grating a certain
Cycle on direction；The double frequency crossed polarized light of described two-frequency laser (11) outgoing incides Amici prism (12), and which is anti-
Z-direction exploring block (6) is incided after penetrating light transmission polaroid A (13), the beat signal of formation is referred to all the way as what Z-direction was measured
Signal, its transmitted light are divided into reference light and measurement light after inciding polarization splitting prism (21)；Described reference light passes through 1/4 ripple
Piece A (22), and after being reflected by reflection part (23), successively through quarter wave plate A (22), polarization splitting prism (21), polaroid B
(25) incide Z-direction exploring block (6)；Described measurement light transmission quarter wave plate B (24) tailing edge Z-direction incides scanning light splitting
Grating (31), after scanned spectro-grating (31) diffraction, diffracted beam incides scale grating (4) and reverse diffraction occurs, reversely
Diffraction light obtains nine beam measuring beams and other spuious light beams through scanning spectro-grating (31) diffraction light splitting；Nine described beams
In measuring beam, wherein OP3-131 and OP3-212, OP3-132 and OP3-213, OP3-312 and OP3-231, OP3-313 with
The direction of propagation is identical two-by-two for OP3-232, incides X and forms four groups of interference signals to exploring block (5), by signal processing unit
(7) resolve after obtain read head relative to scale grating (4) X to occur displacement；It is another in nine described beam measuring beams
One passes through quarter wave plate B (24) along the measuring beam that incident direction is returned, and through polarization after being reflected by polarization splitting prism (21)
Piece B (25) incides Z-direction exploring block (6)；The reference light and measurement light for inciding Z-direction exploring block (6) meets the bat to be formed
The measurement signal all the way that frequency signal is measured as Z-direction, the reference signal and measurement signal of Z-direction measurement pass through signal processing unit
(7) displacement that read head occurs in Z-direction relative to scale grating (4) is obtained after resolving.
2. the two-dimensional displacement measurer of a kind of use double-frequency laser as claimed in claim 1 and diffraction grating, its feature exist
In：Described scanning spectro-grating (31) for one-dimensional rectangular raster when, scale grating (4) includes following structure arrangement mode：①
Scale grating (4) is one-dimensional rectangular raster, and its grid line direction is parallel with the grid line direction of scanning spectro-grating (31)；2. scale
Grating (4) is two-dimensional rectangle grating, and two grid line direction it is parallel with the grid line direction of scanning spectro-grating (31) respectively and
Vertically；3. scale grating (4) is two-dimensional rectangle grating, and two grid line direction grid line respectively with scanning spectro-grating (31)
Direction is at 45 °.
3. the two-dimensional displacement measurer of a kind of use double-frequency laser as claimed in claim 1 and diffraction grating, its feature exist
In：Diaphragm (32), and diaphragm (32) are additionally arranged in described scanning spectro-grating part (3) positioned at scanning spectro-grating
And X is between exploring block (5) (31).
4. the two-dimensional displacement measurer of a kind of use double-frequency laser as claimed in claim 1 and diffraction grating, its feature exist
In：In the wavelength X=632.8nm of two-frequency laser (11) outgoing through the measurement light of scanning spectro-grating (31), 1. institute
The scanning spectro-grating (31) stated adopts one group of preferred parameter of one-dimensional rectangular raster for d=10 μm of screen periods, grating steps
Height h=488nm, a=3.567 μm of grating steps width；The parameter of 2. described scale grating (4) includes：A () works as scale light
Grid (4) using one-dimensional rectangular raster, and its grid line direction with scanning spectro-grating (31) grid line direction it is parallel when, one group is excellent
Radix Ginseng selection number is d=10 μm of screen periods, grating steps height h=488nm, a=3.567 μm of grating steps width；B () works as scale
Grating (4) is using two-dimensional rectangle grating, and two grid line direction is parallel with the grid line direction of scanning spectro-grating (31) respectively
With it is vertical when, one group preferred parameter is the screen periods d in two grid line directions1=d2=10 μm, grating steps height h=
159nm, the grating steps width a in two grid line directions1=a2=5.67 μm；C () is when scale grating (4) is using two-dimensional rectangle light
Grid, and two grid line direction respectively with scanning spectro-grating (31) grid line direction it is at 45 ° when, one group preferred parameter be two
The screen periods in individual grid line direction are d1=d2=7.07 μm, grating steps height h=159nm, two grid line direction grating platforms
Rank width a1=a2=4.01 μm.
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| CN106403821A (en) * | 2015-07-27 | 2017-02-15 | 中国科学院苏州纳米技术与纳米仿生研究所 | Displacement sensor, usage and manufacturing method thereof and interferometer |
| CN105758435B (en) * | 2016-04-14 | 2018-02-09 | 清华大学深圳研究生院 | A kind of absolute grating scale |
| CN107664481B (en) * | 2016-07-29 | 2019-08-23 | 上海微电子装备（集团）股份有限公司 | Grating measuring device |
| CN108180844A (en) * | 2017-12-21 | 2018-06-19 | 复旦大学 | A kind of multiple degrees of freedom precise displacement monitoring system based on double-frequency laser interference principle |
| CN108627100B (en) * | 2018-07-02 | 2020-03-20 | 清华大学 | Two-degree-of-freedom heterodyne grating interferometry system |
| CN109916315B (en) * | 2019-03-29 | 2024-02-23 | 华侨大学 | Measuring device based on separation type grating |
| CN110285761B (en) * | 2019-07-03 | 2021-02-23 | 哈尔滨工业大学 | Grating three-dimensional displacement measuring device with compact structure |
| CN114459516B (en) * | 2022-02-21 | 2023-07-28 | 清华大学深圳国际研究生院 | Absolute six-degree-of-freedom grating encoder |
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