CN109141222A - A kind of U axis interferometer structure - Google Patents
A kind of U axis interferometer structure Download PDFInfo
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- CN109141222A CN109141222A CN201710460914.XA CN201710460914A CN109141222A CN 109141222 A CN109141222 A CN 109141222A CN 201710460914 A CN201710460914 A CN 201710460914A CN 109141222 A CN109141222 A CN 109141222A
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- light
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- beam splitter
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- 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
- G01B9/02027—Two or more interferometric channels or interferometers
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
- G02B27/283—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising used for beam splitting or combining
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Instruments For Measurement Of Length By Optical Means (AREA)
Abstract
A kind of U axis interferometer structure, composition include being followed successively by five axis beam splitting systems and intervention module along polarized orthogonal double-frequency laser incident direction.The five axis beam splitting systems by 4 45o plane beam splitters, 3 45o total reflective mirrors and 1 optical path compensation full impregnated microscope group at.The present invention has many advantages, such as that element easy processing, nonlinearity erron are small, each road light beam temperature drift is consistent and optical path adjusting is convenient.
Description
Technical field
The present invention relates to multi-axis interferometer, especially a kind of U axis interferometer structure.
Background technique
Interferometer is that displacement to destination apparatus, length equivalent carry out the essential tool of accurate measurement.Interfering
In instrument, by the way that the variation of optical path length is converted into displacement to carry out precise measurement to displacement.Two-frequency laser interferometer
Have many advantages, such as high resolution, test the speed that fast, measurement range is big, can carry out multi-axial Simultaneous measurement, is therefore widely used in advanced
In manufacture and nanotechnology, such as the positioning and measurement of high-precision photo-etching machine work-piece platform mask platform.
It, can in order to carry out the measurement of multiple freedom degrees such as length or displacement, axial-rotation amount to destination apparatus simultaneously
Using the multi-axis interferometer comprising multiple laser beams, each laser beam corresponds to a measurement axis of interferometer.Interfere in multiaxis
In instrument, the light beam of multiaxis light splitting must have equal energy and parallel each other.The quality of beam splitting system design is more
The key point of axis subdivision interferometer success or failure.One good beam splitting system can make interferometer have high stability and Ge Lu light beam temperature
Spend the consistency of drift.
Although multi-axis interferometer has been successfully applied to numerous areas, its performance is carried out constantly improve to obtain
Good measurement accuracy, especially the beam splitting system of multi-axis interferometer is continuously improved with obtain preferable stability, compared with
Low temperature drift and nonlinearity erron and controllability are still the target currently constantly pursued.Therefore, the light splitting of multi-axis interferometer
System must carry out well-designed to ensure the measurement error introduced due to optical path imbalance, such as thermal drift and nonlinearity erron
Etc. being reduced to minimum.The multi-axis interferometer of international renowned company plates the bulk of a variety of different desired film layers frequently with single surface
Optical spectroscopic element is for being divided.This light-splitting method is very high to optical manufacturing required precision, and same beam splitter
Will two light pass surfaces plate it is anti-reflection, be all-trans and a variety of different desired film layers such as the spectro-film of various different splitting ratios, to plating
Film creates great difficulties.Further, since the path that each road light splitting light beam is passed by bulk optical beam splitter is different, cause each
The temperature drift of road light beam is inconsistent.Due to the geometric position between each light splitting surface and reflecting surface of bulk optical beam splitter
Be it is fixed, each divided beams can not be adjusted individually.Therefore, there is each road light beams in the application for this beam splitting system
The defects of temperature drift consistency is poor, optical path adjusting is more difficult.
Summary of the invention
It is an object of the invention to overcome above-mentioned the deficiencies in the prior art, a kind of U axis interferometer structure is provided, this is dry
Interferometer has many advantages, such as that element easy processing, optical path adjusting are relatively easy, the road nonlinearity erron little He Ge light beam temperature drift is consistent.
Technical solution of the invention is as follows: a kind of U axis interferometer structure, and it includes edge that feature, which is that it is constituted,
Polarized orthogonal double-frequency laser incident direction is followed successively by five axis
Beam splitting system and intervention module.
The five axis beam splitting systems are complete by 4 45o plane beam splitters and 3 45o total reflective mirrors and 1
Saturating compensating glass composition, positional relationship are as follows:
The first 45o plane beam splitter that one splitting ratio is 40% is set in polarized orthogonal double-frequency laser incident direction, at this
First 45o plane beam splitter is sequentially arranged above splitting ratio 33% the second plane beam splitter and the first 45o total reflective mirror,
2 50% third plane beam splitters, fourth plane spectroscope and a full impregnated mirror are placed sequentially in same hang down from bottom to top
On face, 2
First 45o plane beam splitter by incident polarized orthogonal double-frequency laser be divided into 40% transmitted light beam and 60% it is anti-
Irradiating light beam, the 3rd 45o plane beam splitter of transmitted light beam direction setting 50%, through the 3rd 45o plane beam splitter
It is divided into the equal transmitted light of energy and reflected light is each a branch of, wherein the reflected beams passes after the reflection of the 2nd 45o total reflective mirror
It is parallel with transmitted light to broadcast direction, to form lower layer's A, B light；
The reflected beams that energy through the reflection of the first 45o plane beam splitter is 60% with the first 45o plane then by being divided
The 2nd 45o plane beam splitter that mirror splitting ratio placed in parallel above and below is 33% be divided into again 33% transmitted light beam with
66% the reflected beams；The reflected beams therein are incident on 50% the 4th 45o plane beam splitter, the fourth plane again
Spectroscope is divided into the equal transmitted light beam of energy and the reflected beams, and the reflected beams therein are reflected through the 3rd 45o total reflective mirror again
Afterwards, so that the direction of propagation is parallel with transmitted light, to form middle layer C, D light；
It is passed through again by the transmitted light beam of the second plane beam splitter complete with the second plane beam splitter the first 45o placed in parallel above and below
Also change its direction of propagation and parallel with above-mentioned each divided beams after the reflection of anti-mirror；The light beam is incident on shape after a full impregnated mirror again
At upper layer E light, the use of full impregnated mirror is to make in beam splitting system per the transmission range of light beam in the medium all the way as far as possible
It is equal, to guarantee the consistency of each road light beam temperature drift；In this way, from laser export a branch of double-frequency laser by this five
Be divided into the five beam light that energy is equal and is parallel to each other after axis beam splitting system, upper layer is a branch of, in, each two beam of lower layer.
The intervention module includes polarization spectroscope, is the first quarter-wave in the light transmission direction of the polarization spectroscope
Piece and measurement reflecting mirror, are the second quarter-wave plate and reference mirror in the reflection light direction of the polarization spectroscope, at this
The four directions of polarization spectroscope is equipped with five right-angle prisms of three-layer arrangement from bottom to top.The fixed interference of the reference mirror
Inside instrument, the measurement reflecting mirror is fixed on object being measured, such as photo-etching machine work-piece platform.
Five right-angle prisms are provided that first layer from bottom to top: the first right-angle prism, the second right-angled edge
Mirror；The second layer: third right-angle prism, the 4th right-angle prism；Third layer: the 5th right-angle prism.
Using one with series 45o plane beam splitter (40%, 33% and 50% splitting ratio) and 45o reflecting mirror
Incident light is divided into five equal beam directional lights of energy by five axis beam splitting systems.This five beams directional light is, respectively, used as 5 certainly
By the accurate measurement spent.Due to using this beam splitting system, compared with common blocky beam splitting system, corresponding to 5 surveys
It measures transmission range of the 5 beam light of axis in quartz or glass medium significantly to shorten, and this transmission of 5 beam light in the medium
Be equidistant, so as to so that each road light beam temperature drift consistency be improved significantly, each measurement can also be effectively reduced
Axis measurement error as caused by thermal drift.Further, since each 45o plane beam splitter and 45o in the beam splitting system are anti-
Penetrating mirror can individually be adjusted, therefore the light beam for corresponding to each measurement axis also can be separately adjustable.
Light source is usually He-Ne two-frequency laser, and exporting a branch of tool, there are two energy is equal, polarization direction is orthogonal
Linearly polarized light beam, the two polarized components have the frequency difference and high frequency stability of several MHz.
One polarization spectroscope again will according to the difference of polarization characteristic by the five beam directional lights after five axis beam splitting systems
Every light beam is divided into measurement light and reference light.Five measuring beams are the light that five beam light transmit after polarization spectroscope, and five
A reference beam is then five beam light reflected lights after polarization spectroscope.Similarly, if the component of interferometer carried out
Appropriate to reconfigure, reference beam can be interchanged with measuring beam, and the function of interferometer is constant.
Five measuring beams be transferred to after common quarter-wave plate measurement reflecting mirror on, after being reflected using
Quarter-wave plate enters polarization spectroscope.Since five beam measuring beams pass twice through quarter-wave plate, the measurement of five beams
The polarization direction of light beam is rotated by 90 °, to keep the five beam measuring beams for being again introduced into polarization spectroscope inclined in polarization spectroscope
Transmission is reflected rather than on vibration face.Five beam measuring beams after reflection enter five right-angle prisms, are then reflected back to again
Polarization spectroscope.By the reflection of polarization spectroscope, five beam measuring beams will be fed again into measurement reflecting mirror and reflect.
After passing twice through quarter-wave plate, the polarization direction of five beam measuring beams is rotated by 90 ° again, to make
The five beam measuring beams for being again introduced into polarization spectroscope are transmitted output on polarization spectroscope plane of polarization, realize 4 subdivisions
Function improves the resolution ratio of interferometer.
Polarization spectroscope also produces five beam reference beams, they are that five beam incident lights are reflected after polarization spectroscope
Light beam.Five reference beams are incident on reference mirror after common quarter-wave plate, after its reflection again
Enter public polarization spectroscope by quarter-wave plate, plane of polarization rotates 90o.By the transmission of polarization spectroscope and five
The turnover of right-angle prism, five beam reference beams will again pass by common polarization spectroscope, quarter-wave plate and with reference to reflections
Mirror repeats the above process, when the reference beam that polarization direction is rotated by 90 ° again reaches polarization spectroscope 45o plane of polarization,
It will be reflected out, and realize 4 subdivision functions, improve the resolution ratio of interferometer.
Subsequent five beam closes beam with reference to output beam and five beams measurement output beam respectively, forms 5 output beam 19-
23, each outgoing beam contains the reference beam collinearly transmitted and measuring beam is each a branch of, a corresponding measurement optical axis.
Output beam by detector detect and handled through computer software, by analyze the reference beam in each outgoing beam and
Beat signal between measuring beam solves the Doppler shift information of the moving object in beat signal, so that it may obtain five
The object of which movement information of freedom degree.
Compared with the existing technology, the present invention has following technical characterstic:
1, five axis beam splitting systems are made of 4 45 ° of plane beam splitters and 3 reflective mirrors and 1 full impregnated mirror.One
Incident polarization laser is divided into two bundles by 40% spectroscope first, wherein 40% transmitted light beam is incident on one 50% point again
45 ° of plane beam splitters of light ratio, and it is divided into the equal transmitted light of energy through the spectroscope and reflected light is each a branch of, reflection therein
Light passes through 45 ° of total reflective mirrors again, so that above-mentioned reflected light is parallel with transmitted light；And pass through first 40% plane light splitting
The transmitted light beam that the energy reflected after mirror is 66% then passes through one and its point being placed in parallel on same vertical line
Light is than being divided into transmitted light and reflected light is each a branch of again after 45 ° of plane beam splitters for 33%；Similarly, energy therein
For 66% the reflected beams again via 45 ° of plane beam splitters of 50% splitting ratio be divided into the equal transmitted light of energy and
Reflected light is each a branch of, and after so that reflected light therein is again passed by 45 ° of total reflective mirrors with transmitted light parallel transmission；And it passes through
Cross the light beam that the energy transmitted after 45 ° of plane beam splitters that splitting ratio is 33% is 33% then pass through one and its in same
Also change its direction of propagation and parallel with above-mentioned each divided beams after 45 ° of total reflective mirrors being placed in parallel on vertical line, the subsequent light beam is again
It is transmitted after a full impregnated mirror along former direction, so that the transmission range phase as far as possible of the road beam splitting system Zhong Ge light beam in the medium
Deng to guarantee the consistency of each road light beam temperature drift.In this way, from laser export a branch of double-frequency laser by this five
Finally it is divided into five equal beam light of energy after axis beam splitting system and is parallel to each other, respectively as the light of five axis of interferometer
Source provides the accurate measurement of five freedom degrees.
2, due in the beam splitting system each 45o plane beam splitter and 45o reflecting mirror can individually adjust,
Light beam corresponding to each measurement axis also can be separately adjustable.And since entire beam splitting system only used plane light splitting
The combination of mirror and reflecting mirror plates the bulk optical beam splitter that a variety of differences require film layer on single surface with what is generallyd use
It compares, has many advantages, such as that element is easy production processing.
3, due to using this beam splitting system being only combined by plane beam splitter and reflecting mirror, so that each light splitting
The path that road is passed by beam splitter is identical, and corresponding to 5 beam light of 5 measurement axis in quartz or glass medium
In transmission range significantly shorten, therefore compared with usually used bulk optical beam splitter system, have temperature drift small and every
The advantages that temperature drift of light beam is consistent all the way.
Claims (3)
1. a kind of U axis interferometer structure, be characterized in that its composition include along polarized orthogonal double-frequency laser incident direction successively
There are five axis beam splitting systems and intervention module.
2. a kind of U axis interferometer structure according to claim 1, it is characterised in that: the five axis beam splitting systems
By 4 45o plane beam splitters and 3 45o total reflective mirrors and 1 optical path compensation full impregnated microscope group at positional relationship
It is as follows: polarized orthogonal double-frequency laser (IN) incident direction be arranged splitting ratio be 40%(its be reflected into 60%) first
45o plane beam splitter (1), being sequentially arranged above splitting ratio 33%(it be reflected into the first 45o plane beam splitter (1)
66%) the second plane beam splitter (2) and the first 45o total reflective mirror (3), 2 50% third plane beam splitters (4), Siping City
Face spectroscope (5) and a full impregnated mirror (6) are placed sequentially in from bottom to top on the same vertical plane, 2 the 2nd 45o total reflective mirrors
(7), the 3rd 45o total reflective mirror (8) is placed sequentially in from bottom to top on another vertical plane in parallel；
First 45o plane beam splitter (1) by incident polarized orthogonal double-frequency laser (IN) be divided into 40% transmitted light beam and
60% the reflected beams, the 3rd 45o plane beam splitter (4) of transmitted light beam direction setting 50%, through the 3rd 45o
Plane beam splitter 4) it is divided into the equal transmitted light of energy and reflected light is each a branch of, wherein the reflected beams are through the 2nd 45o total reflective mirror
(7) after reflecting, the direction of propagation is parallel with transmitted light, to form lower layer's A, B light；
Through the first 45o plane beam splitter (1) reflection energy be 60% the reflected beams, by with the first 45o plane
The 2nd 45o plane beam splitter (2) that spectroscope (1) splitting ratio placed in parallel above and below is 33%, 66% the reflected beams enter
It is mapped to 50% the 4th 45o plane beam splitter (5), is divided into the equal transmitted light of energy through the fourth plane spectroscope (5)
Beam and the reflected beams, the reflected beams therein again through the 3rd 45o total reflective mirror (8) reflection after so that the direction of propagation and transmission
Light is parallel, to form middle layer C, D light；
It is passed through again and the second plane beam splitter (2) placed in parallel above and below first by the transmitted light beam of the second plane beam splitter (2)
Also change its direction of propagation and parallel with above-mentioned each divided beams after 45o total reflective mirror (3) reflection；The light beam is incident on one again
Full impregnated mirror (6) (optical path compensation) forms upper layer E light afterwards；In this way, a branch of double-frequency laser exported from laser is by being somebody's turn to do
Be divided into the five beam light that energy is equal and is parallel to each other after five axis beam splitting systems, upper layer is a branch of, in, each two beam of lower layer.
3. a kind of U axis interferometer structure according to claim 1, it is characterised in that: the intervention module includes
Polarization spectroscope (9) is the first quarter-wave plate (10) and measurement in the transmission light direction of the polarization spectroscope (9)
Reflecting mirror (12) is the second quarter-wave plate (11) and reference reflection in the reflection light direction of the polarization spectroscope (9)
Mirror (13) is equipped with five right-angle prisms of three-layer arrangement from bottom to top in the four directions of the polarization spectroscope (9).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710460914.XA CN109141222A (en) | 2017-06-18 | 2017-06-18 | A kind of U axis interferometer structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710460914.XA CN109141222A (en) | 2017-06-18 | 2017-06-18 | A kind of U axis interferometer structure |
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| Publication Number | Publication Date |
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| CN109141222A true CN109141222A (en) | 2019-01-04 |
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| CN201710460914.XA Pending CN109141222A (en) | 2017-06-18 | 2017-06-18 | A kind of U axis interferometer structure |
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| PB01 | Publication | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20190104 |
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| WD01 | Invention patent application deemed withdrawn after publication |