CN201653358U - Novel linear diffraction grating interferometer structure - Google Patents
Novel linear diffraction grating interferometer structure Download PDFInfo
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- CN201653358U CN201653358U CN2009202997974U CN200920299797U CN201653358U CN 201653358 U CN201653358 U CN 201653358U CN 2009202997974 U CN2009202997974 U CN 2009202997974U CN 200920299797 U CN200920299797 U CN 200920299797U CN 201653358 U CN201653358 U CN 201653358U
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Abstract
The utility model relates to a novel linear diffraction grating interferometer structure, which comprises a semiconductor laser device, a reflecting grating and a reflecting mirror. A first polarizing spectral prism is arranged between the semiconductor laser device and the reflecting mirror, a depolarizing prism, a second polarizing spectral prism and a third polarizing spectral prism are further arranged on one side of the first polarizing spectral prism, and photoelectric detectors for receiving signal light are respectively arranged on the second polarizing spectral prism and the third polarizing spectral prism. The structure realizes superposition and interference of diffraction light by using the least amount of lenses, simplifies mounting and adjustment, and reduces optical element surfaces so as to reduce redundant reflecting beams and improves signal quality. By adopting a symmetric structural design, the structure eliminates optical path difference theoretically, increases interference fringe contrast ratio and improves the signal quality. Additionally the structure has the advantage of definite displacement optimal light path, thereby realizing certainty of mounting and adjustment.
Description
Technical field
The utility model relates to optical instrument field, especially a kind of novel linear diffraction-grating inter-ferometer structure.
Background technology
The contradiction that big stroke and high precision face in the displacement transducer design often, is held grid and is had big stroke measurment ability traditional magnetic grid, but precision often is confined to pitch; The sensitivity of inductance, piezoresistive transducer and precision are all higher, but measurement range is limited; Laser interferometer is a kind of large stroke and high precision sensor commonly used, but price is higher, and to the environmental requirement harshness, because optical maser wavelength very easily is subjected to such environmental effects such as temperature, air turbulence.
The principle of raster pattern interferometry is to utilize the grating of motion to produce the two-way diffracted beam, diffraction light is because the effect of Doppler effect, can produce the frequency displacement of opposite in sign, again join to produce and interfere, can obtain the interferometric fringe signal that frequency and movement velocity are directly proportional, through signal Processing and counting segmentation, can make displacement measurement.Grating interferometer is a kind of displacement transducer based on the grating interference principle, and its pitch of using grating is as the displacement standard, but not optical maser wavelength, thereby has improved the stability of reading greatly.And when the laser beam incident grid, because spot definition is much larger than grating pitch, so the groove error also becomes very little under the effect of average effect.
The grating interferometer that has had in the prior art, all use cheap semiconductor laser organ pipe as light source, and adopt ± 1 order diffraction light to interfere, eliminate optical path difference by structural design or compensation, prevent laser retroeflection semiconductor laser by polar biased, left-handed right-handed rotation enters the phase shift module in its light path, produce the interference signal of 90 ° of four tunnel phase phasic differences, and use differential input so that eliminate dc shift, amplify useful signal, its light channel structure can be divided into the light path laminating module and interfere the phase shift module.But the grating interferometer of prior art all has weak point, grating interferometer as the design of the Heidenhain company of Britain, it is used for changing the wave plate of polarization direction and is used for the unpolarized light splitting piece of beam split all certain thickness, introduced optical path difference, make that the light path that goes up symmetry for how much is also asymmetric on light path, thereby cause interfering contrast to reduce; Unpolarized light splitting piece has certain thickness, because the existence of refraction, left and right sides light beam can not overlap fully; In addition, this design is based on a hypothesis, and promptly the light beam that sends of semiconductor laser has the polarizability near perfect condition, and the outgoing beam of most semiconductor lasers is partial poolarized light on the actual market, does not satisfy such ideal hypothesis.
The utility model content
The purpose of this utility model provides a kind of novel linear diffraction-grating inter-ferometer structure, uses less optical instrument, can obtain higher light signal quality, to solve the existing in prior technology problem.
In order to achieve the above object, the technical scheme that the utility model adopted is:
A kind of novel linear diffraction-grating inter-ferometer structure, include semiconductor laser, reflective gratings, it is characterized in that: also include first polarization splitting prism of cubic and two catoptrons of adjustable angle, the one side of described first polarization splitting prism is over against the light-emitting window of described semiconductor laser, be incidence surface, the plane of symmetry of the described first polarization splitting prism incidence surface, and the position of two the symmetrical faces adjacent with incidence surface is respectively arranged with quarter wave plate, its quick shaft direction of described quarter wave plate is 45 °, described two catoptrons are symmetrical, be arranged at a side of the plane of symmetry of the described first polarization splitting prism incidence surface respectively, an and side that is provided with the adjacent surface of quarter wave plate of incidence surface, the light that described semiconductor laser sends is incident on the light splitting surface of described first polarization splitting prism, light splitting surface is crossed in part transmittance, behind a quarter wave plate, by one of them mirror reflects to described reflective gratings, another part light is reflected by light splitting surface, after passing through another quarter wave plate again, reflexed to described reflective gratings by another transmitting mirror, described catoptron makes two-beam be incident to described reflective gratings with special angle respectively, in reflection grating, form diffraction, adjust mirror angle to make ± 1 order diffraction reflection of light light is incident to described first polarization splitting prism along original optical path, crossed light path coincidence behind the light splitting surface by light splitting surface reflection and transmission respectively again, described coincidence light through the 3rd quarter wave plate after outgoing;
The depolarization Amici prism that also comprises cubic, a plurality of photodetectors, described depolarization Amici prism simultaneously is an incidence surface, the incidence surface of described depolarization Amici prism is over against the emergent light of described the 3rd quarter wave plate with described the 3rd quarter wave plate of reception process, the one side that one side reaches and incidence surface is contiguous relative with incidence surface on the corresponding described depolarization Amici prism is respectively arranged with second of cubic, the 3rd polarization splitting prism, describedly be incident to described depolarization Amici prism through the emergent light behind the 3rd quarter wave plate, be divided into transmitted light and the reflected light that energy equates by the light splitting surface of described depolarization Amici prism, described transmitted light and reflected light pass described depolarization Amici prism respectively, be incident to described second, the 3rd polarization splitting prism, described second, the light splitting surface of the 3rd polarization splitting prism is divided into incident light transmission respectively and two parts that be reflected, in correspondence described second, transmitted light and catoptrical mirror position are respectively arranged with photodetector to receive described second in the 3rd polarization splitting prism, one-tenth transmitted light and reflected light in the 3rd polarization splitting prism.
Described a kind of novel linear diffraction-grating inter-ferometer structure is characterized in that: between described semiconductor laser and described first polarization splitting prism, the photodetector rear of the described reception second polarization splitting prism transmitted light is respectively arranged with pin hole.
Described a kind of novel linear diffraction-grating inter-ferometer structure, it is characterized in that: described reflective gratings the place ahead is provided with baffle plate, and retaining removes the diffraction reflection light of unwanted progression.The advantage that the utlity model has is as follows:
(1) stack and the interference of diffraction light have been realized with the eyeglass of minimum number.Simplified to install and adjusted, reduced optical element surface, thereby reduced redundant folded light beam, improved signal quality.
(2) symmetrical structure design has been eliminated optical path difference from principle, has increased the interference fringe contrast, improves signal quality,
(3), so can install with any spacing between optical system and the grating because in the utility model, the diffraction light direction is that the former road of former incident light direction is returned; Adjust mirror angle and can realize that diffraction light returns by the former road of incident light direction, use the grating of littler pitch if obtain high measurement resolution more, need only readjust mirror angle to get final product, so the design has upgrading space.
(4) the optimum light path of displacement is clear and definite, has realized installing the determinacy of adjusting.
(5) eyeglass adopts common size, and technical maturity is cheap.
(6) laser instrument adopts cheap semiconductor laser.
(7) miniaturization Design.PBS and NPBS are that 5 millimeters ribs are long, and quarter wave plate is 4 mm side lengths, 1 millimeter thickness.Overall dimensions is 50mm*50mm*15mm.
(8) high precision, 15 millimeters interior measuring repeatabilities that obtain less than 10 nanometers of range.
Description of drawings
Fig. 1 is the utility model light channel structure figure.
Embodiment
A kind of novel linear diffraction-grating inter-ferometer structure, include semiconductor laser 1, reflective gratings 4, also include first polarization splitting prism 3 of cubic and two catoptrons 8 of adjustable angle, 9, the one side of first polarization splitting prism 3 is over against the light-emitting window of semiconductor laser, be incidence surface, the plane of symmetry of first polarization splitting prism, 3 incidence surfaces, and the position of two the symmetrical faces adjacent with incidence surface is respectively arranged with quarter wave plate 6,5,7, quarter wave plate 5,6,7 its quick shaft directions are 45 °, two catoptrons 8,9 is symmetrical, be arranged at a side of the plane of symmetry of first polarization splitting prism, 3 incidence surfaces respectively, an and side that is provided with the adjacent surface of quarter wave plate 5 of incidence surface, the light that semiconductor laser 4 sends is incident on the light splitting surface of first polarization splitting prism 3, light splitting surface is crossed in part transmittance, behind a quarter wave plate 6, reflexed to reflective gratings 4 by one of them catoptron 9, another part light is reflected by light splitting surface, after passing through another quarter wave plate 5 again, reflexed to reflective gratings 4 by another transmitting mirror 8, catoptron 8,9 make two-beam be incident to reflective gratings 4 with 22.4 ° of specific incident angles respectively, because the diffraction light angle is decided by grating 4 pitch, incident angle and diffraction progression, so adjust catoptron 8,9 angles make ± and 1 order diffraction reflection of light light is incident to first polarization splitting prism 3 along original optical path, light path overlaps after being crossed light splitting surface by light splitting surface reflection and transmission respectively again, overlaps light through 7 outgoing afterwards of the 3rd quarter wave plate;
The depolarization Amici prism 10 that also comprises cubic, four photodetectors 13,14,15,16, depolarization Amici prism 10 one sides are incidence surface, the incidence surface of depolarization Amici prism 10 over against the 3rd quarter wave plate 7 to receive emergent light through the 3rd quarter wave plate 7, the one side that one side reaches and incidence surface is contiguous relative with incidence surface on the corresponding depolarization Amici prism 10 is respectively arranged with second of cubic, the 3rd polarization splitting prism 11,12, be incident to depolarization Amici prism 10 through the emergent light behind the 3rd quarter wave plate 7, be divided into transmitted light and the reflected light that energy equates by the light splitting surface of depolarization Amici prism 10, transmitted light and reflected light pass depolarization Amici prism 10 respectively, be incident to second, the 3rd polarization splitting prism 11,12, second, the 3rd polarization splitting prism 11,12 light splitting surface is divided into incident light transmission respectively and two parts that be reflected, transmitted light and catoptrical mirror position are respectively arranged with photodetector 14 in corresponding second polarization splitting prism 11,13 to receive one-tenth transmitted light and the reflected light in second polarization splitting prism 11, transmitted light and catoptrical mirror position are respectively arranged with photodetector 15 in corresponding the 3rd polarization splitting prism 12,16 receiving one-tenth transmitted light and the reflected light in the 3rd polarization splitting prism 12.
Between the semiconductor laser 1 and first polarization splitting prism 3, photodetector 14 rears that receive second polarization splitting prism, 11 transmitted lights are respectively arranged with pin hole 2,18.
Reflective gratings 4 the place aheads are provided with baffle plate 17, and retaining removes the diffraction reflection light of unwanted progression.
The utility model uses reflective gratings, and what interfere is ± 1 order diffraction light.The light beam that when wavelength is λ is with incident angle θ
iIncident pitch is the reflective gratings 4 of d, produces the multiple tracks diffraction light, and establishing angle of diffraction is θ
q, m is a diffraction progression, then above parameter has following relation:
d(sinθ
i+sinθ
q)＝mλ (1)
Semiconductor laser 1 emitting laser bundle is a partial poolarized light, can be so that the polarization ellipse major axis is positioned at 45 ° of directions by suitable adjustment.First polarization splitting prism 3 is divided into two identical bunch polarized lights of energy with this light beam, and the polarization direction is respectively level (P light) and vertical (S light).P light passes first polarization splitting prism, 3 inclined-planes, constitutes right light arm.S light then is reflected, and constitutes left light arm.By (1) formula as can be known, specific diffraction light angle is by the decision of the pitch of incident angle of light and grating, by adjusting the angle of catoptron 8,9, can so that-1 order diffraction light of left light arm and right light arm+1 order diffraction light follows the input path direction and returns.For example use the grating of 1 millimeter 1200 line, can calculate incident angle by formula (1) is 22.4 °. Quarter wave plate 5,6 and 7 quick shaft direction are that 45 ° of directions are placed, and can realize the mutual conversion of linearly polarized light and circularly polarized light.With left light arm is example, S light is through quarter wave plate 5, be converted into left-hand polarization light, follow mirror 8 reflections that are reflected of-1 order diffraction light that Yuan Lu returns, when passing through quarter wave plate 5 once more, be converted into P light, the light that then returns can't be by first polarization splitting prism, 3 reflective surface reflected back semiconductor lasers 1, but pass first polarization splitting prism 3, incident quarter wave plate 7; Similarly process also occurs in right light arm, and+1 order diffraction light is converted into S light, is reflected incident quarter wave plate 7 when returning first polarization splitting prism 3 by light splitting surface.The light beam polarization direction that this moment, two-way was joined is orthogonal, can not interfere, and is converted into left-handed and right-handed polarized light respectively through the effect of quarter wave plate 7.Be divided into identical two of energy through depolarization Amici prism 10,, be respectively formed at the interference on 0 °, 45 °, 90 ° and the 135 ° of directions again by the effect of the 3rd polarization splitting prism 12 and second polarization splitting prism 11.And then on four photodetectors 13,14,15,16, can obtain the quadrature string ripple signal of 90 ° of phase phasic differences:
I
PD1＝A[1-cos(2Δω·t)] (2)
I
PD2＝A[1+cos(2Δω·t)] (3)
I
PD3＝A[1+sin(2Δω·t)] (4)
I
PD4＝A[1-sin(2Δω·t)] (5)
Beyond this ultimate principle, install and the improvement signal quality for the ease of adjusting, increased some details of optimizing structure in the utility model newly:
Near the position of grating one baffle plate 17 is being set, intercept left light arm+-1 order diffraction light of 1 order diffraction light and right light arm enters light path.
Claims (3)
1. novel linear diffraction-grating inter-ferometer structure, include semiconductor laser, reflective gratings, it is characterized in that: also include first polarization splitting prism of cubic and two catoptrons of adjustable angle, the one side of described first polarization splitting prism is over against the light-emitting window of described semiconductor laser, be incidence surface, the plane of symmetry of the described first polarization splitting prism incidence surface, and the position of two the symmetrical faces adjacent with incidence surface is respectively arranged with quarter wave plate, its quick shaft direction of described quarter wave plate is 45 °, described two catoptrons are symmetrical, be arranged at a side of the plane of symmetry of the described first polarization splitting prism incidence surface respectively, an and side that is provided with the adjacent surface of quarter wave plate of incidence surface, the light that described semiconductor laser sends is incident on the light splitting surface of described first polarization splitting prism, light splitting surface is crossed in part transmittance, behind a quarter wave plate, by one of them mirror reflects to described reflective gratings, another part light is reflected by light splitting surface, after passing through another quarter wave plate again, reflexed to described reflective gratings by another transmitting mirror, described catoptron makes two-beam be incident to described reflective gratings with special angle respectively, in reflection grating, form diffraction, adjust mirror angle to make ± 1 order diffraction reflection of light light is incident to described first polarization splitting prism along original optical path, crossed light path coincidence behind the light splitting surface by light splitting surface reflection and transmission respectively again, described coincidence light through the 3rd quarter wave plate after outgoing; The depolarization Amici prism that also comprises cubic, a plurality of photodetectors, described depolarization Amici prism simultaneously is an incidence surface, the incidence surface of described depolarization Amici prism is over against the emergent light of described the 3rd quarter wave plate with described the 3rd quarter wave plate of reception process, the one side that one side reaches and incidence surface is contiguous relative with incidence surface on the corresponding described depolarization Amici prism is respectively arranged with second of cubic, the 3rd polarization splitting prism, describedly be incident to described depolarization Amici prism through the emergent light behind the 3rd quarter wave plate, be divided into transmitted light and the reflected light that energy equates by the light splitting surface of described depolarization Amici prism, described transmitted light and reflected light pass described depolarization Amici prism respectively, be incident to described second, the 3rd polarization splitting prism, described second, the light splitting surface of the 3rd polarization splitting prism is divided into incident light transmission respectively and two parts that be reflected, in correspondence described second, transmitted light and catoptrical mirror position are respectively arranged with photodetector to receive described second in the 3rd polarization splitting prism, one-tenth transmitted light and reflected light in the 3rd polarization splitting prism.
2. a kind of novel linear diffraction-grating inter-ferometer structure according to claim 1 is characterized in that: between described semiconductor laser and described first polarization splitting prism, the photodetector rear of the described reception second polarization splitting prism transmitted light is respectively arranged with pin hole.
3. a kind of novel linear diffraction-grating inter-ferometer structure according to claim 1, it is characterized in that: described reflective gratings the place ahead is provided with baffle plate, and retaining removes the diffraction reflection light of unwanted progression.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2009202997974U CN201653358U (en) | 2009-12-31 | 2009-12-31 | Novel linear diffraction grating interferometer structure |
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| CN2009202997974U CN201653358U (en) | 2009-12-31 | 2009-12-31 | Novel linear diffraction grating interferometer structure |
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| CN103630077A (en) * | 2013-12-12 | 2014-03-12 | 哈尔滨工业大学 | Two-axis grating displacement measurement system adopting double-frequency laser |
| CN104613865A (en) * | 2015-02-15 | 2015-05-13 | 中国科学院上海光学精密机械研究所 | Grating interferometer with high subdivision and high density |
| CN104634254A (en) * | 2015-03-06 | 2015-05-20 | 中国科学院光电技术研究所 | Grating displacement measuring system based on heterodyne interference and secondary diffraction effect |
| CN106289068A (en) * | 2016-07-22 | 2017-01-04 | 清华大学 | A kind of two degrees of freedom heterodyne grating interferometer displacement measurement method |
| CN106403824A (en) * | 2016-10-25 | 2017-02-15 | 合肥工业大学 | Grating interferometer based precision altimeter |
| CN104729402B (en) * | 2015-03-23 | 2017-05-03 | 中国科学院上海光学精密机械研究所 | High-optical-subdivision grating interferometer based on plane mirrors |
| CN106796098A (en) * | 2014-07-14 | 2017-05-31 | 齐戈股份有限公司 | Use the interference encoder of spectrum analysis |
| CN106918920A (en) * | 2017-04-20 | 2017-07-04 | 长春理工大学 | Using polarizing CO2The apparatus and method of laser interference machining lens antifog structure |
| CN109883362A (en) * | 2019-03-11 | 2019-06-14 | 华侨大学 | A kind of straight line degree measurement system based on grating interference principle |
| CN115755420A (en) * | 2022-09-26 | 2023-03-07 | 北京航天计量测试技术研究所 | Diffraction grating interference light path beam combining device and method |
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- 2009-12-31 CN CN2009202997974U patent/CN201653358U/en not_active Expired - Fee Related
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103630077A (en) * | 2013-12-12 | 2014-03-12 | 哈尔滨工业大学 | Two-axis grating displacement measurement system adopting double-frequency laser |
| CN103630077B (en) * | 2013-12-12 | 2016-05-11 | 哈尔滨工业大学 | A kind of diaxon grating displacement measuring system that uses double-frequency laser |
| CN106796098B (en) * | 2014-07-14 | 2020-03-24 | 齐戈股份有限公司 | Interferometric encoder using spectral analysis |
| CN106796098A (en) * | 2014-07-14 | 2017-05-31 | 齐戈股份有限公司 | Use the interference encoder of spectrum analysis |
| CN104613865A (en) * | 2015-02-15 | 2015-05-13 | 中国科学院上海光学精密机械研究所 | Grating interferometer with high subdivision and high density |
| CN104634254A (en) * | 2015-03-06 | 2015-05-20 | 中国科学院光电技术研究所 | Grating displacement measuring system based on heterodyne interference and secondary diffraction effect |
| CN104729402B (en) * | 2015-03-23 | 2017-05-03 | 中国科学院上海光学精密机械研究所 | High-optical-subdivision grating interferometer based on plane mirrors |
| CN106289068B (en) * | 2016-07-22 | 2018-10-30 | 清华大学 | A kind of two degrees of freedom heterodyne grating interferometer displacement measurement method |
| CN106289068A (en) * | 2016-07-22 | 2017-01-04 | 清华大学 | A kind of two degrees of freedom heterodyne grating interferometer displacement measurement method |
| CN106403824A (en) * | 2016-10-25 | 2017-02-15 | 合肥工业大学 | Grating interferometer based precision altimeter |
| CN106918920A (en) * | 2017-04-20 | 2017-07-04 | 长春理工大学 | Using polarizing CO2The apparatus and method of laser interference machining lens antifog structure |
| CN109883362A (en) * | 2019-03-11 | 2019-06-14 | 华侨大学 | A kind of straight line degree measurement system based on grating interference principle |
| CN109883362B (en) * | 2019-03-11 | 2024-02-02 | 华侨大学 | Straightness measurement system based on grating interference principle |
| CN115755420A (en) * | 2022-09-26 | 2023-03-07 | 北京航天计量测试技术研究所 | Diffraction grating interference light path beam combining device and method |
| CN115755420B (en) * | 2022-09-26 | 2023-09-01 | 北京航天计量测试技术研究所 | Diffraction grating interference light path beam combining device and method |
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Granted publication date: 20101124 Termination date: 20171231 |