CN102278945B - Optical displacement sensor - Google Patents
Optical displacement sensor Download PDFInfo
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- CN102278945B CN102278945B CN 201110191500 CN201110191500A CN102278945B CN 102278945 B CN102278945 B CN 102278945B CN 201110191500 CN201110191500 CN 201110191500 CN 201110191500 A CN201110191500 A CN 201110191500A CN 102278945 B CN102278945 B CN 102278945B
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- quartz crystal
- prism
- displacement sensor
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Abstract
The invention provides an optical displacement sensor based on the principle of optical rotation effect of quartz crystals. Positive and negative isosceles right-triangular quartz crystal prisms are adopted in the optical displacement sensor and the change of displacement is converted into the change of an optical rotation angle, so as to acquire displacement information by detecting the received light intensity. The optical displacement sensor comprises a laser device (1), a first polarization beam splitter prism (2), a displacement sensing element (3), a second polarization beam splitter prism (4), a first photoelectric detector (5), a second photoelectric detector (6) and a division arithmetic unit (7) which are arranged in sequence, wherein the displacement sensing element (3) is composed of a first quartz crystal prism (A) and a second quartz crystal prism (B) which are arranged up and down, have identical shapes and properties, have positive and negative specific rotary powers and are in the shape of an isosceles right-triangle; the two opposite bottoms of the first quartz crystal prism (A) and the second quartz crystal prism (B) are integrally glued by use of an optical cement; and the optical axis directions of the first quartz crystal prism (A) and the second quartz crystal prism (B) are vertical to the two opposite bottoms.
Description
Technical field
The present invention relates to a kind of optical displacement sensor, belong to the technical field of Photoelectric Detection, photoelectric sensing and optical information processing.
Background technology
Displacement is one of physical quantity common and important in the engineering detecting, can indirectly measure the physical quantitys such as stress, temperature, speed by displacement detecting
[1]The displacement detecting technology is exactly that displacement is converted to the detection method that other measurable physical quantity of determining relation is arranged with it.Along with the development of industrial technology, the very important and application that displacement detecting becomes is very extensive, such as science and technology measurement, aut.eq., Machine-Tool Control etc.Displacement transducer mainly is divided into contact and contactless two kinds, and tangent displacement sensor generally is based on electronic technology
[2], sensors with auxiliary electrode were is subject to the interference of the environmental factors such as electromagnetism easily.In the non-contact displacement transducer optical means use more, such as the method using in optic fiber displacement sensor technology
[3], optical interference techniques
[4], the grating measurement technology
[5]Deng, but their general operation accuracy requirement is high, and make also relative complex.
The present invention is based on quartz crystal rotation effect principle, propose a kind of optical displacement sensor.Sensor adopts two forms that quartz crystal combines, and compares with using a quartz crystal, and detection sensitivity doubles; Because quartz crystal has high specific rotation characteristic, therefore guaranteed higher displacement detecting precision; Adopt double light path acquisition of signal technology, can eliminate the influence factors such as absorption of light source luminescent power swing and light intensity; The employing of optical means has overcome the shortcoming of common electrical magnetic-type displacement transducer so that this sensor is not subjected to the interference of the environmental factors such as electromagnetism; This sensor construction principle is simple, cost of manufacture is low and be easy to realize that real-time online measures automatically.The invention of this patent achievement can well be applied to the displacement sensing field.
List of references
[l] Wei Renxuan, Jiang Desheng. fiber F-P microdisplacement measurement experimental study [J]. optical instrument, 2003,25 (5): 7～9
[2] Liu Dequan, Wang Xiaohua. the capacitor grid transducer principle of work [J] of large displacement measurement. Dalian light industry journal, 1997,16 (2): 18～22
[3] Zhao Yong, Li Pengsheng, the clear nation in Pu. optical fibre displacement sensor progress and application [J1. sensor technology, 1999,18 (2): 2～6
[4] Li Zhineng, Shen Liang, Zhou Xiaodong. Modulated polarization insensitive interferometric fiber-optic sensor [J]. journal of Zhejiang university, 2002,36 (1): 56～59
[5] Jiang Desheng, He Wei. the application scenario of fiber-optic grating sensor [J]. photoelectron laser, 2002,13 (4): 420～430
Summary of the invention
Technical matters: the object of the invention is to propose a kind of optical displacement sensor, solve displacement optical detection problem.Sensor adopts the double light path Detection Techniques can eliminate the unstable and light intensity absorption factor of light source luminescent power; Adopt optical means so that this sensor is not subjected to the interference of the environmental factors such as electromagnetism, overcome the shortcoming of common electrical magnetic-type displacement transducer; This sensor construction is simple, make easily, cost is low, be easy to realize that real-time online measures automatically; Can well be applied to the displacement sensing field.
Technical scheme: a kind of optical displacement sensor of the present invention comprises tactic laser instrument, the first polarization beam splitter prism, displacement sensor, the second polarization beam splitter prism, the first photodetector, the second photodetector, divider; Wherein sensing element is comprised of two isosceles right angle trigonometry type the first quartz crystal prism and the second quartz crystal prisms block-shaped, that the identical specific rotation of performance is respectively positive and negative up and down, two bottom surfaces that the first quartz crystal prism is relative with the second quartz crystal prism become an integral body with the optics glue glued adhesion, and the optical axis direction of the first quartz crystal prism and the second quartz crystal prism is perpendicular to its two relative bottom surfaces.
The inclined-plane of the first quartz crystal prism and the second quartz crystal prism plates respectively with the protective eccentric reflective film, makes light constant at reflection place polarization state.
The first photodetector, the second photodetector adopts the identical photodetector of model specification.
If quartz crystal A and the B specific rotation under laser wavelength lambda is respectively ± α; When displacement sensor 3 maintained static, establishing light spread length along optical axis direction in A was L
A, light spread length along optical axis direction in B is L
BThen light is through L
AAnd L
BAfter total optically-active angle be:
β＝L
A·α-L
B·α (1)
If be I through the initial incident intensity after the first polarization beam splitter prism reflection
0, then the receiving light power of photodetector 5 is:
I
1＝I
0cos
2(β)＝I
0cos
2(L
A·α-L
B·α) (2)
Then the receiving light power of photodetector 6 is:
I
2＝I
0sin
2(β)＝I
0sin
2(L
A·α-L
B·α) (3)
The relative value of divider 7 outputs is:
a＝I
2/I
1＝tg
2(L
A·α-L
B·α) (4)
After displacement sensor 3 made progress displacement S, then the change of distance along the optical axis direction light transmition was Δ L in crystal A and B
A=Δ L
B=Δ S, then light spread length along optical axis direction in A is:
L
A'=L
A-Δ L
A=L
A-Δ S, the light spread length along optical axis direction in B is:
L
B'=L
B+ Δ L
B=L
B+ Δ S, then light in A and B along the total optically-active angle of optical axis direction is:
β′＝L
A′·α-L
B′·α＝(L
A-ΔS)·α-(L
B+ΔS)·α (5)
Then the receiving light power of photodetector 5 is at this moment:
I
1′＝I
0cos
2(β′)＝I
0cos
2(L
A·α-L
B·α-2ΔS·α) (6)
This moment, the receiving light power of photodetector 6 was:
I
2′＝I
0sin
2(β′)＝I
0sin
2(L
A·α-L
B·α-2ΔS·α) (7)
This moment, the relative value of divider 7 outputs was:
b＝I
2′/I
1′＝tg
2(L
A·α-L
B·α-2ΔS·α) (8)
Can draw displacement by (4) formula and (8) formula:
Beneficial effect: according to above narration as can be known, the present invention has following features:
The present invention is based on quartz crystal rotation effect principle, propose a kind of optical displacement sensor.Sensor adopts two forms that quartz crystal combines, and compares with using a quartz crystal, and detection sensitivity doubles; Because quartz crystal has high specific rotation characteristic, therefore guaranteed higher displacement detecting precision; Adopt double light path acquisition of signal technology, can eliminate the influence factors such as absorption of light source luminescent power swing and light intensity; The employing of optical means has overcome the shortcoming of common electrical magnetic-type displacement transducer so that this sensor is not subjected to the interference of the environmental factors such as electromagnetism; This sensor construction principle is simple, cost of manufacture is low and be easy to realize that real-time online measures automatically.The invention of this patent achievement can well be applied to the displacement sensing field.
Description of drawings
A kind of optical displacement sensor system architecture of Fig. 1 synoptic diagram,
Have among the figure: laser instrument 1, the first polarization beam splitter prism 2, displacement sensor 3, the second polarization beam splitter prisms 4, photodetector 5,6, divider 7.
Embodiment
Embodiment 1
A kind of optical displacement sensor equipment therefor of the present invention as shown in Figure 1.Among Fig. 1,1 is laser instrument.2 is the first polarization beam splitter prism.3 is displacement sensor, and it is comprised of upper and lower two block structures and the identical isosceles right angle trigonometry of performance type quartz crystal prism A and B, and A and B are glued together with its level two bottom surfaces by optical cement, thereby consist of a whole sensing element; One is positive crystal among requirement A and the B, and another piece is negative crystal; The inclined-plane plates respectively with the protective eccentric reflective film, makes light constant in place, inclined-plane reflex time polarization state; The optical axis direction of crystal A and B is perpendicular to its two bottom surfaces direction, shown in tag line " | " in the quartz crystal among the figure.The laser that laser instrument 1 sends becomes the polarization direction perpendicular to the linearly polarized light of paper after reflecting through the first polarization beam splitter prism 2, this linearly polarized light along continuous straight runs vertical incidence enters quartz crystal A in the displacement sensor 3, and this moment, the light transmition perpendicular direction was in optical axis direction; Under the protective eccentric reflective on the inclined-plane of quartz crystal A, the polarization direction of light still is the linearly polarized light perpendicular to paper, and light is propagated (namely propagating perpendicular to the bottom surface of quartz crystal A) along the direction of quartz crystal A optical axis, vertical incidence enters crystal B after being transmitted to the bottom surface of crystal A, the direction of propagation also is optical axis direction in crystal B, be transmitted to behind the inclined-plane of crystal B under the effect of protective eccentric reflective film, light is along leaving sensing element 3 perpendicular to the direction horizontal output of optical axis.Therefore light produced optically-active owing to propagating along optical axis direction in the process from A to B, thereby leave the oscillating component and the oscillating component that is parallel to paper that have produced in the displacement sensor 3 rear light perpendicular to paper, after entering polarization beam splitter prism 4, oscillating component perpendicular to paper is received by photodetector 5, the oscillating component that is parallel to paper is received by photodetector 6, photodetector 5 and 6 inputs to divider 7 with the intensity signal that receives and processes, and final output contains the result of calculation of sensing element 3 displacement informations.
If quartz crystal A and the B specific rotation under laser wavelength lambda is respectively ± α; When displacement sensor 3 maintained static, establishing light spread length along optical axis direction in A was L
A, light spread length along optical axis direction in B is L
BThen light is through L
AAnd L
BAfter total optically-active angle be:
β＝L
A·α-L
B·α (10)
If be I through the initial incident intensity after the first polarization beam splitter prism reflection
0, then the receiving light power of photodetector 5 is:
I
1＝I
0cos
2(β)＝I
0cos
2(L
A·α-L
B·α) (11)
Then the receiving light power of photodetector 6 is:
I
2＝I
0sin
2(β)＝I
0sin
2(L
A·α-L
B·α) (12)
The relative value of divider 7 outputs is:
a＝I
2/I
1＝tg
2(L
A·α-L
B·α) (13)
After displacement sensor 3 made progress displacement S, then the change of distance along the optical axis direction light transmition was Δ L in crystal A and B
A=Δ L
B=Δ S, then light spread length along optical axis direction in A is:
L
A'=L
A-Δ L
A=L
A-Δ S, the light spread length along optical axis direction in B is:
L
B'=L
B+ Δ L
B=L
B+ Δ S, then light in A and B along the total optically-active angle of optical axis direction is:
β′＝L
A′·α-L
B′·α＝(L
A-ΔS)·α-(L
B+ΔS)·α (14)
Then the receiving light power of photodetector 5 is at this moment:
I
1′＝I
0cos
2(β′)＝I
0cos
2(L
A·α-L
B·α-2ΔS·α) (15)
This moment, the receiving light power of photodetector 6 was:
I
2′＝I
0sin
2(β′)＝I
0sin
2(L
A·α-L
B·α-2ΔS·α) (16)
This moment, the relative value of divider 7 outputs was:
b＝I
2′/I
1′＝tg
2(L
A·α-L
B·α-2ΔS·α) (17)
Can draw displacement by (4) formula and (8) formula:
Specific embodiment 2
A kind of optical displacement sensor equipment therefor of the present invention as shown in Figure 1.1 is laser instrument among Fig. 1.2 is the first polarization beam splitter prism.3 is displacement sensor, and it is comprised of upper and lower two block structures and the identical isosceles right angle trigonometry of performance type quartz crystal prism A and B, and A and B are glued together with its two bottom surface by optical cement, thereby consist of a whole sensing element; One is positive crystal among requirement A and the B, and another piece is negative crystal; The inclined-plane plates respectively with the protective eccentric reflective film, makes light constant in place, inclined-plane reflex time polarization state; The optical axis direction of crystal A and B is perpendicular to its two bottom surfaces direction, shown in tag line " | " in the quartz crystal among the figure.The laser that laser instrument 1 sends becomes the polarization direction perpendicular to the linearly polarized light of paper after reflecting through the first polarization beam splitter prism 2, this linearly polarized light along continuous straight runs vertical incidence enters quartz crystal A in the displacement sensor 3, and this moment, the light transmition perpendicular direction was in optical axis direction; Under the protective eccentric reflective on the inclined-plane of quartz crystal A, the polarization direction of light still is the linearly polarized light perpendicular to paper, and light is propagated (namely propagating perpendicular to the bottom surface of quartz crystal A) along the direction of quartz crystal A optical axis, vertical incidence enters crystal B after being transmitted to the bottom surface of crystal A, the direction of propagation also is optical axis direction in crystal B, be transmitted to behind the inclined-plane of crystal B under the effect of protective eccentric reflective film, light is along leaving sensing element 3 perpendicular to the direction horizontal output of optical axis.Therefore light produced optically-active owing to propagating along optical axis direction in the process from A to B, thereby leave the oscillating component and the oscillating component that is parallel to paper that have produced in the displacement sensor 3 rear light perpendicular to paper, after entering polarization beam splitter prism 4, oscillating component perpendicular to paper is received by photodetector 5, the oscillating component that is parallel to paper is received by photodetector 6, photodetector 5 and 6 inputs to divider 7 with the intensity signal that receives and processes, and final output contains the result of calculation of sensing element 3 displacement informations.
If quartz crystal A and the B specific rotation under laser wavelength lambda is respectively ± α; When displacement sensor 3 maintained static, establishing light spread length along optical axis direction in A was L
A, light spread length along optical axis direction in B is L
BThen light is through L
AAnd L
BAfter total optically-active angle be:
β＝L
A·α-L
B·α (19)
If be I through the initial incident intensity after the first polarization beam splitter prism reflection
0, then the receiving light power of photodetector 5 is:
I
1＝I
0cos
2(β)＝I
0cos
2(L
A·α-L
B·α) (20)
Then the receiving light power of photodetector 6 is:
I
2＝I
0sin
2(β)＝I
0sin
2(L
A·α-L
B·α) (21)
The relative value of divider 7 outputs is:
a＝I
2/I
1＝tg
2(L
A·α-L
B·α) (22)
Behind displacement sensor 3 downward displacement S, then the change of distance along the optical axis direction light transmition is Δ L in crystal A and B
A=Δ L
B=Δ S, then light spread length along optical axis direction in A is:
L
A'=L
A+ Δ L
A=L
A+ Δ S, the light spread length along optical axis direction in B is:
L
B'=L
B-Δ L
B=L
B-Δ S, then light in A and B along the total optically-active angle of optical axis direction is:
β′＝L
A′·α-L
B′·α＝(L
A+ΔS)·α-(L
B-ΔS)·α (23)
Then the receiving light power of photodetector 5 is at this moment:
I
1′＝I
0cos
2(β′)＝I
0cos
2(L
A·α-L
B·α+2ΔS·α) (24)
This moment, the receiving light power of photodetector 6 was:
I
2′＝I
0sin
2(β′)＝I
0sin
2(L
A·α-L
B·α+2ΔS·α) (25)
This moment, the relative value of divider 7 outputs was:
b＝I
2′/I
1′＝tg
2(L
A·α-L
B·α+2ΔS·α) (26)
Can draw displacement by (4) formula and (8) formula:
Claims (3)
1. optical displacement sensor, it is characterized in that this sensor comprises tactic laser instrument (1), the first polarization beam splitter prism (2), displacement sensor (3), the second polarization beam splitter prism (4), the first photodetector (5), the second photodetector (6), divider (7); Wherein sensing element (3) is comprised of two isosceles right angle trigonometry type the first quartz crystal prism (A) and the second quartz crystal prisms (B) block-shaped, that the identical specific rotation of performance is respectively positive and negative up and down, the first quartz crystal prism (A) becomes an integral body with two relative horizontal bottom of the second quartz crystal prism (B) with the optics glue glued adhesion, and the optical axis direction of the first quartz crystal prism (A) and the second quartz crystal prism (B) is perpendicular to its two relative horizontal bottom.
2. optical displacement sensor as claimed in claim 1 is characterized in that the inclined-plane of the first quartz crystal prism (A) and the second quartz crystal prism (B) plates respectively with the protective eccentric reflective film, makes light constant at reflection place polarization state.
3. optical displacement sensor as claimed in claim 1 is characterized in that the first photodetector (5), and the second photodetector (6) adopts the identical photodetector of model specification.
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| CN 201110191500 CN102278945B (en) | 2011-07-08 | 2011-07-08 | Optical displacement sensor |
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|---|---|---|---|
| CN 201110191500 CN102278945B (en) | 2011-07-08 | 2011-07-08 | Optical displacement sensor |
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| CN102278945B true CN102278945B (en) | 2013-03-06 |
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| CN110595366B (en) * | 2019-09-19 | 2021-06-22 | 南京邮电大学 | Two-dimensional optical displacement sensor |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101021563A (en) * | 2007-03-16 | 2007-08-22 | 清华大学 | Double-refraction external cavity displacement measuring system |
| CN200972385Y (en) * | 2006-11-24 | 2007-11-07 | 浙江理工大学 | Interference system of displacement and angle synchronous measuring based on Faraday optical effect |
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2011
- 2011-07-08 CN CN 201110191500 patent/CN102278945B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN200972385Y (en) * | 2006-11-24 | 2007-11-07 | 浙江理工大学 | Interference system of displacement and angle synchronous measuring based on Faraday optical effect |
| CN101021563A (en) * | 2007-03-16 | 2007-08-22 | 清华大学 | Double-refraction external cavity displacement measuring system |
Non-Patent Citations (1)
| Title |
|---|
| 毛庆国.基于旋光效应的微位移检测研究.《中国优秀硕士学位论文全文数据库 信息科技辑》.2008,(第4期),第35-61页. * |
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