CN1335483A - Tumble angle measuring method and measurer - Google Patents

Abstract

The present invention belongs to the field of optical angle measuring technology, and includes setting half-reflecting mirror in the output light axis of Zeeman laser, setting half wave plate perpendicularly in the transmission light path of the half-reflecting mirror, and setting half wave plate, analyzer, one first photoelectronic detector successively and perpendicular second photoelectronic detector in the reflection light path; and one phase meter with input connected to the output of the first and the second photoelectronic detectors and output to the computer. The present invention has strengthened non-linearity and 4 times raised sensitivity, and the close measuring detectors and light source results in compact structure and ever high practicability.

Description

Roll angle measurement method and rolling angle measurement instrument thereof

Technical field:

The invention belongs to the field of optical measuring technologies of angle, particularly roll angle measurement method and rolling angle measurement instrument thereof.

Background technology:

Roll angle is an important parameter in the error compensation.Roll angle in the surface level can be measured with electrolevel, and ready-made instrument is arranged.And though the roll angle in the vertical plane is had methods such as polarimetry, precision is not very high always, can not satisfy the needs of practical application.

The Kao Lunkaiweiqi of USSR (Union of Soviet Socialist Republics) equals proposition in 1974, uses the left and right sides rounding polarized light of the vertical zeeman laser of double frequency to realize rolling angle measurement, and its structure and principle are as shown in Figure 1.

Among the figure, the source of double-frequency laser is vertical zeeman laser, and senser element is an analyzer 11, and its roll angle is α, and the left and right sides rounding polarization light frequency of incident light is respectively f1 and f2.12 beat signal is on the photodetector:

S＝Acos[2π(f ₂-f ₁)t+ ₀+Δψ] (1)

Phase difference ψ is directly proportional with roll angle in the formula:

Δψ＝2α (2)

As long as the phase place of measuring beat signal just can obtain the size of roll angle, both are linear relationship, and measurement result does not rely on the amplitude of signal, and are promptly irrelevant with light intensity, have realized that the physical quantity from the roll angle to the phase of ac signal transforms.According to the document, use resolution is 0.003 ° phasometer, and the phase-measurement accuracy that obtains is 0.01 °, and corresponding mechanical corner accuracy is 0.005 °, and (18 "), nonlinearity erron complete cycle at phasing degree is 2 °.The author of the document thinks that Measurement Uncertainty is difficult to be improved to 0.0028 ° (below 10 ").

As seen, though said method has realized that polarization direction with laser is benchmark and tested angle converted to phase of ac signal, sensitivity is too low, does not reach the requirement of application.

Propositions such as the Jiang Hong of Tsing-Hua University are a kind of to utilize non-linear raising sensitivity, can realize on a large scale, highly sensitive roll angle measurement method.It is characterized in that in light path, adding quarter wave plate, thereby replace circularly polarized light, can improve tens of times measuring sensitivity with the elliptically polarized light of quadrature.

The formation of this method and principle of work may further comprise the steps as shown in Figure 2: 1, adopting transverse zeeman laser is light source 21, and this laser instrument is exported orthogonal orhtogonal linear polarizaiton light

With

2, allow this orhtogonal linear polarizaiton light by a quarter-wave plate 22, this wave plate optical axis and polarized light have certain angle theta, make it become the elliptically polarized light of quadrature;

3, this elliptic polarization light is again by the analyzer 23 as sensor;

4, at last receive the ac signal that will obtain and reference signal than mutually, thereby obtain the information of tested roll angle α by the photodetector (not shown).

Prove that by Theoretical Calculation measurement is feasible to said method to roll angle, its principle is: suppose that incident light 21 is the linearly polarized light of pair of orthogonal

21, amplitude is A ₁, A ₂, circular frequency is ω ₁, ω ₂, back by the ellipse elliptically polarized light that turns to quadrature partially by quarter-wave plate 22.Analyzer 23 is a senser element, and its roll angle is α.For convenience of calculation, the quick shaft direction of getting quarter-wave plate is an X-direction, polarized component

With the X-axis angle be θ.

Analyze with Jones matrix, can obtain emergent light and be:

Incident light vector in the formula: Rotation matrix: $R\left(\mathrm{\θ}\right)=\left[\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right]$ , quarter-wave plate: $Q=\left[\begin{array}{cc}1& 0\\ 0& i\end{array}\right]$ , analyzer: $P\left(\mathrm{\α}\right)=\left[\begin{array}{cc}{\cos }^2\mathrm{\α}& \sin \mathrm{\α}\cos \mathrm{\α}\\ \sin \mathrm{\α}\cos \mathrm{\α}& {\sin }^2\mathrm{\α}\end{array}\right]$ , the Jones matrix substitution of each device is calculated, can get:

={ K ₁A ₁Exp{-i[ω ₁T+ ₁+ arctan (tan θ tan α)] } (4) $+k_2{A}_2\exp \{-i\[{\mathrm{\ω}}_{2}t+{\mathrm{\φ}}_2+\arctan (\cot \mathrm{\θ}\·\tan \mathrm{\α})\]\}\}$ $\left[\begin{array}{c}\cos \mathrm{\α}\\ \sin \mathrm{\α}\end{array}\right]$ In the formula $k_1=\sqrt{{\cos }^2{\mathrm{\θ}\cos }^2\mathrm{\α}+{\sin }^2\mathrm{\θsi}{n}^2\mathrm{\α}}$ $k_2=\sqrt{{\sin }^2\mathrm{\θ}{\cos }^2\mathrm{\α}+{\cos }^2\mathrm{\θ}{\sin }^2\mathrm{\α}}---\left(5\right)$

As can be seen from the above equation, the light of two frequency components has produced different phase change respectively.The light intensity I that further calculating can be synthesized according to formula (4) is:

Last Δ ψ promptly is the additional phase error that is caused by roll angle in the formula

Δψ＝arctan(tanθ·tanα)+arctan(cotθ·tanα) (7)

Receive this Shu Guang with photodetector, obtain measuring-signal S after the output signal elimination flip-flop _Mea:

S _mea＝K _mea·2k ₁k ₂A ₁A ₂cos[(ω ₁-ω ₂)t+ ₁- ₂+Δψ+δ _mea] (8)

K in the formula _MeaBe the responsiveness of measuring light electric explorer, δ _MeaThe additional phase error that causes for metering circuit.Similarly, can obtain a reference signal S from laser instrument _Ref: $S_{\mathrm{ref}}=K_{\mathrm{ref}}\·2\sqrt{I_1^{\′}{I}_2^{\′}}\cos \[({\mathrm{\ω}}_1-{\mathrm{\ω}}_2)t+{\mathrm{\φ}}_1^{\′}-{\mathrm{\φ}}_2^{\′}+{\mathrm{\δ}}_{\mathrm{ref}}\]---\left(9\right)$

K in the formula _RefBe the responsiveness of reference light electric explorer, δ _RefThe additional phase error that causes for reference circuit.So the phase differential of measuring-signal and reference signal is: = ₀+ Λ ψ= ₀+ arctan (tan θ tan α)+arctan (cot θ tan α) (10)

wherein ₀=( ₁- ₂+ δ _Mea)-( ₁'- ₂'+δ _Ref) be constant.For making following discussion convenient, it is omitted, conclusion is not exerted an influence, (10) formula can be reduced to:

＝Λψ＝arctan(tanθ·tanα)+arctan(cotθ·tanα) (11)

Following formula has provided the dependence of the phase shift of beat signal generally speaking to analyzer corner α.

Provided under several groups of different θ angles relation curve of the two among Fig. 3.

As we can see from the figure, the relation curve of the phase shift of beat signal and roll angle depends on the ellipse degree of bias of incident light.Two polarized components are left and right sides rounding polarized light just when θ=45 °, and the two is linear relationship completely, and angle of phase displacement is the twice of roll angle.Two polarized components are ellipse polarisation during θ ≠ 45 °, and it is non-linear that phase change is, and θ is more little, and nonlinearity is big more, at 0 °, 90 °, 180 ° ... Deng place's angle of phase displacement the variation of roll angle is very high susceptibility.

When in the measuring process to roll angle, what need to pay close attention to is: is the most responsive to the variation of α under what conditions, and promptly defines angular magnification K about the derivative maximum of α for this reason _aFor: $K_{\mathrm{\α}}=\frac{\mathrm{d\φ}}{\mathrm{d\α}}---\left(12\right)$

K _aThe expression phasing degree will seek out measurement effect preferably undoubtedly for the sensitivity of roll angle, will obtain big as far as possible K _aValue.Be not difficult from the graph to find no matter how θ changes, curve slope on the whole remains 2 forever, the increase of its slope local be with strengthen whole non-linear be the cost realization.So, obtain big K _aValue just requires that shows the strong nonlinear dependence to α on whole angles.In addition, although is the nonlinear function of α on the whole, wish that the two can retention wire sexual intercourse, i.e. K within enough big measurement range _aRemain constant, otherwise can bring nonlinearity erron to measurement.In a word, the requirement to function = (α) is:

1). all have strong nonlinear → increase angular magnification on the field of definition

2). the interval retention wire sexual intercourse within measurement range → avoid nonlinearity erron

Above-mentioned 2 is mutual contradiction at first view, but as can be seen from Figure 3, the steep ascent stage of curve is linear substantially, may therefrom obtain the linear measurement interval, have simultaneously and have very high sensitivity.The funtcional relationship of formula (11) can satisfy this 2 point simultaneously.Because it is the periodic function of α and θ that formula (11) shows , below only discuss at the angular range of (90 °＜α＜+90 °) and (0 °≤θ≤45 °).

Analysis mode (9) as can be known, in α → 0, θ → 0, tan α tan θ＜＜1 o'clock can be approximated to be:

＝(tanθ+cotθ)α (13)

Accordingly, angular magnification is,

K _a＝tanθ+cotθ (14)

Obviously, when θ=45 °, K _a=2, formula (11) deteriorates to formula (2), is above-mentioned metering system based on circularly polarized light.And θ ≠ 45 °, K _a＞2, so under the constant situation of other condition, obtained higher measurement sensitivity.Simultaneously, formula (11) illustrates that also it is linear measuring relation in certain roll angle scope.Fig. 4 has represented K _aWith the situation of change of θ, this figure shows and can obtain very big sensitivity multiplication constant from curve.

Seeing that from figure the size of nonlinearity erron and roll angle is tangent relationship, is a kind of tangent error, sharply increases with the increase of roll angle.The measuring accuracy of considering most of phasing degree is according to calculating the linear measurement range of this measuring method less than the nonlinearity erron of this numerical value above figure that can ignore between 0.1 ° to 0.01 °.During θ=1 °-5 °, its linear measurement range is approximately ± and 0.1 ° to ± 0.5 °, be equivalent to ± 180 " to ± 900 ".This has substantially exceeded the possible roll angle of guide rail, and its range of linearity is enough to practical application.Simultaneously, the bigger range of linearity is indicating that also this measuring method allows bigger initial alignment error, can be applied in the occasions such as installation, calibration of workpiece.

In sum, the range of roll angle is taken as-180 "＜α＜180 ".

Can set up rolling angle measurement system according to above-mentioned ultimate principle as Fig. 5:

This system has with the lower part and constitutes: frequency stabilization transverse zeeman laser 51, semi-transparent semi-reflecting lens 52, quarter-wave plate 54, analyzer 55, two photodetectors (53,56), phasometer 57, computing machine 58.

The crossed polarized light of transverse zeeman laser 51 output is divided into two bundles earlier through semi-transparent semi-reflecting lens 52 with incident light, and a branch of conduct is with reference to light, another Shu Zuowei measuring light.Measuring light is earlier through quarter-wave plate 54, linearly polarized light is become elliptically polarized light, synthesize through analyzer 55 then as sensor, receive by photodetector 56 at last and convert ac signal---measuring-signal to, use again phasometer 57 with reference signal and measuring-signal than mutually, the result is delivered to computing machine 58 carries out the measurement result that data processing obtains roll angle

The sensitivity of this system has improved 30-50 doubly than the measuring method of people such as the Kao Lunkaiweiqi proposition of USSR (Union of Soviet Socialist Republics).

Summary of the invention

The objective of the invention is to propose a kind of roll angle measurement method and rolling angle measurement instrument thereof, make sensitivity on the basis of non-linear enhancing, improve 4 times again, with the close light source of measuring light detector, can make structure become more compact simultaneously, to strengthen the practicality of instrument.

A kind of roll angle measurement method that the present invention proposes may further comprise the steps:

1) by the stable quadrature double frequency linearly polarized laser of light source output frequency, and through being beamed into measuring light and reference light, this reference light is received by photodetector becomes reference signal;

2) this orhtogonal linear polarizaiton measuring light is carried out ovalization, make it to become elliptically polarized light;

3) make this elliptically polarized light through survey sensor;

4) make this light through the secondary reflection backtracking again, for the second time through said survey sensor;

5) this light is synthetic by analyzer again;

6) this light is received the ac signal that will obtain and said reference signal than mutually by photodetector at last, thereby obtains the information of tested roll angle.

The present invention proposes to adopt the rolling angle measurement device of said method, comprise a frequency stabilization transverse zeeman laser light source, semi-transparent semi-reflecting lens, quarter-wave plate, analyzer, two photodetectors, phasometer, computing machine, it is characterized in that, also comprise 1/2nd wave plates, catoptron, this semi-transparent semi-reflecting lens is set on the optical axis of said transverse zeeman laser output terminal, on the transmission optical axis of this semi-transparent semi-reflecting lens, be vertically installed with 1/2nd wave plates, and on the reflection optical axis of this catoptron, be vertically installed with 1/2nd wave plates successively, the analyzer and first photodetector; Be vertically installed with second photodetector on the reflection optical axis of this semi-transparent semi-reflecting lens, the input end of said phasometer links to each other with the output terminal of this first photodetector, second photodetector, and the output terminal of said phasometer links to each other with said computing machine.

The course of work of apparatus of the present invention is: crossed polarized light earlier through semi-transparent semi-reflecting lens, is divided into two bundles with incident light, and a branch of conduct is with reference to light, another Shu Zuowei measuring light.Measuring light is earlier through quarter-wave plate, linearly polarized light is become elliptically polarized light, produce once multiplication through 1/2nd wave plates for the first time then as sensor, light is folded back through two secondary reflections then, produce multiplication for the second time by 1/2nd wave plates for the second time, synthesize through analyzer then, receive by photodetector at last and convert ac signal---measuring-signal to, again with phasometer with reference signal and measuring-signal than mutually, the result is delivered to computing machine carries out the measurement result that data processing obtains roll angle that worktable is produced.

The present invention has further improved the sensitivity of rolling angle measurement, four multiplications aspect sensitivity, have been realized to the measuring method of propositions such as the Jiang Hong of Tsing-Hua University, simultaneously, right-angle reflecting prism is returned light path, make receiver and light source together, it is compact that structure becomes, and further improved the adaptability of rolling angle measurement instrument.

Description of drawings

Fig. 1 is the roll angle measurement method principle schematic of existing use left and right sides rounding polarized light.

Fig. 2 is a roll angle measurement method principle schematic of utilizing non-linear employing quadrature elliptically polarized light.

Fig. 3 is the phase shift of method shown in Figure 2 and the theory relation curve map of roll angle.

Fig. 4 is the K of method shown in Figure 2 _aRelational theory curve (α → 0) with θ.

Fig. 5 is the device synoptic diagram that utilizes the elliptically polarized light realization rolling angle measurement of non-linear employing quadrature.

Fig. 6 is a rolling angle measurement apparatus structure synoptic diagram of the present invention.

The specific embodiment

Content of the present invention is described in detail as follows in conjunction with each drawings and Examples

A kind of roll angle measurement method that the present invention proposes may further comprise the steps:

1) by the stable quadrature double frequency linearly polarized laser of light source output frequency, and measure light and reference light through being beamed into, This reference light is received by photodetector becomes reference signal;

2) this orhtogonal linear polarizaiton is measured light and carry out ovalization, make it to become elliptically polarized light;

3) make this elliptically polarized light through measuring transducer;

4) this light is through two secondary reflection backtrackings, for the second time through said measuring transducer;

5) this light is more synthetic by analyzer;

6) this light is received the ac signal that will obtain and said reference signal than phase by photodetector at last, Thereby obtain the information of tested roll angle.

In the method, adopt 1/2nd wave plates as sensor, can make the corner multiplication of plane of polarization, again through two Secondary reflection turns back light path, by 1/2nd wave plates, can obtain rational changes in coordinates through two secondary reflections for the second time, Produce an error angle so that work as sensor (1/2nd wave plates) with measured object, obtain 4 times error at receiving position The angle together with non-linear humidification, can obtain 200 times sensitivity enhancement in theory.

The principle of said method of the present invention is described as follows:

With Jones matrix the inventive method is analyzed, can be obtained emergent light and be:

In the formulaThe light of frequency stabilization transverse zeeman laser output, its light vectorSpin matrix $R\left(\mathrm{\θ}\right)=\left[\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right],$ , quarter-wave plate $Q=\left[\begin{array}{cc}1& 0\\ 0& -1\end{array}\right],$ / 2nd wave plates $H\left(a\right)=\left[\begin{array}{cc}\cos 2\mathrm{\α}& \sin 2\mathrm{\α}\\ \sin 2\mathrm{\α}& -\cos 2\mathrm{\α}\end{array}\right],$ , analyzer $P=\left[\begin{array}{cc}1& 0\\ 0& 0\end{array}\right]$ Can be calculated: $=\{k_1{A}_1{e}^{-i[{\mathrm{\ω}}_{1}t+{\mathrm{\φ}}_1+\mathrm{arctg}(\mathrm{tb\θ}\·\mathrm{tg}4\mathrm{\α})]}+k_2{A}_2{e}^{-i[{\mathrm{\ω}}_{2}t+{\mathrm{\φ}}_2-\mathrm{arctg}(\mathrm{ctg\θ}\·\mathrm{tg}4\mathrm{\α})]}\}$ In the formula $k_1=\sqrt{{\cos }^2\mathrm{\θ}{\cos }^{2}4\mathrm{\α}+{\sin }^2\mathrm{\θ}{\sin }^{2}4\mathrm{\α}},k_2=\sqrt{{\sin }^2\mathrm{\θ}{\cos }^{2}4\mathrm{\α}+{\cos }^2\mathrm{\θ}{\sin }^{2}4\mathrm{\α}}$ Further calculating synthetic light intensity I is:Last beat signal for detecting has comprised additional phase error Δ ψ, Δ ψ=arctg (tg θ tg4 α)+arctg (ctg θ tg4 α) (19) angular magnification K in the formula_aFor: $K_a=\frac{d\left(\mathrm{\Δ\ψ}\right)}{\mathrm{d\α}}$

In the time of near α=0, can be approximated to be from (6), (7) formula:

Δψ＝4(tgθ+ctgθ)α                        (21)

K _a＝4(tgθ+ctgθ)                            (22)

The scheme that this shows the propositions such as the Jiang Hong of angular magnification Tsing-Hua University of scheme improves 4 times. So that in theory may Reach the multiplication constant more than 200 times.

The rolling angle measurement device of the employing said method that the present invention proposes, as shown in Figure 6.

This system has following part to consist of: frequency stabilization transverse zeeman laser 601, semi-transparent semi-reflecting lens 602, four minutes One of wave plate 604,1/2nd wave plates 605, right-angle reflecting prism 606, speculum 607, analyzer 608, two Photodetector (603,609), phasometer 610, computer 611.

The crossed polarized light of transverse zeeman laser 601 outputs passes through earlier semi-transparent semi-reflecting lens 602, and incident light is divided into two bundles, A branch of conduct is with reference to light, and another Shu Zuowei measures light. Measure light and pass through earlier quarter-wave plate 604, linearly polarized light is become Become elliptically polarized light, produce once multiplication, then light through 1/2nd wave plates 605 as sensor for the first time then Line is folded back through corner cube mirror 606, produces for the second time multiplication, then warp by 1/2nd wave plates 605 for the second time Cross analyzer 608 and synthesize, received by photodetector 609 at last and convert ac signal---measuring-signal to, Use again phasometer 610 with reference to signal and measuring-signal than mutually, the result is delivered to computer 611 carries out data and process and obtain The measurement result of the roll angle that workbench 612 is produced.

The embodiment one of apparatus of the present invention: adopt SGJ-1 type dual-frequency transverse Zeeman laser, precision frequency stabilization 10^-7, frequency difference 269K, two photodetector cut-off frequencies are 2M, and phasometer adopts Denmark phasometer (Phase Meter Type:2997), phase-measurement accuracy 0.1 degree. On the basis of the principle of the invention, directly utilize transverse zeeman laser itself Residual ovalization, thereby can omit quarter wave plate, reduce the drift link. May reach on this Systems Theory 200 with On multiplication constant, at present the total multiplication constant of sensitivity is 110.

Its roll angle measurement method is as follows:

1, to export orthogonal frequency discrimination be f to transverse zeeman laser₁And f₂Linearly polarized light;

2, allowing crossed polarized light pass through a quarter-wave plate (wave plate optical axis and polarised light have certain angle) just becomes The elliptically polarized light of handing over (because the linearly polarized light of transverse zeeman laser output has certain ovalization, can be directly sharp Use this ovalization, omit this step);

3, make sensor with 1/2nd wave plates, light produces once roll angle for the first time by 1/2nd wave plates Multiplication;

4, light is folded back through right-angle prism;

5, for the second time through sensor 1/2nd wave plates, because having carried out rational coordinate to light, right-angle prism becomes Change, so after light passed through 1/2nd wave plates for the second time, roll angle produced multiplication again, namely has been exaggerated 4;

6, light is synthesized by analyzer again;

7, last light is received the ac signal that will obtain and reference signal than phase by photodetector, thereby obtains quilt Survey the information of roll angle.

Present embodiment has obtained 3 " standard deviations under the condition of using at present 0.1 ° of phasometer. Considerably beyond former Soviet Union's water Flat. The raising potentiality of level are very big along with surveying mutually, for example, if adopt the phasometer (essence identical with Kao Lunkaiweiqi The degree 0.003 the degree), can reach 0.1 " level.

The embodiment two of apparatus of the present invention: it forms device and parameter is basic identical with embodiment one, just uses size instead / 2nd littler wave plates are made sensor, and measurement light is only passed through once, and the light that returns does not pass through 1/2nd wave plates, May reach like this multiplication constant more than 100 on the Systems Theory, the total multiplication constant of sensitivity that experiment obtains is 80. Also can obtain very high certainty of measurement.

Its roll angle measurement method is as follows:

1, transverse zeeman laser is exported orthogonal linearly polarized light E₁And E₂；

2, allowing crossed polarized light pass through a quarter-wave plate (wave plate optical axis and polarised light have certain angle) just becomes The elliptically polarized light of handing over (because the linearly polarized light of transverse zeeman laser output has certain ovalization, can be directly sharp Use this ovalization, omit this step);

3, make sensor with 1/2nd wave plates, light produces once roll angle for the first time by 1/2nd wave plates Multiplication;

4, light is folded back through right-angle prism; (return projector is no longer by 1/2nd wave plates)

5, light is synthesized by analyzer again;

6, last light is received the ac signal that will obtain and reference signal than phase by photodetector, thereby obtains quilt Survey the information of roll angle.

Present embodiment has obtained 3 " standard deviations under the condition of using at present 0.1 ° of phasometer. Considerably beyond former Soviet Union's water Flat. The raising potentiality of level are very big along with surveying mutually, for example, if adopt the phasometer (essence identical with Kao Lunkaiweiqi The degree 0.003 the degree), we can reach 0.1 " level.

Claims (3)

1, a kind of roll angle measurement method may further comprise the steps:

1) by the stable quadrature double frequency linearly polarized laser of light source output frequency, and through being beamed into measuring light and reference light, this reference light is received by photodetector becomes reference signal;

2) this orhtogonal linear polarizaiton measuring light is carried out ovalization, make it to become elliptically polarized light;

3) make this elliptically polarized light through survey sensor;

4) make this light through the secondary reflection backtracking again, for the second time through said survey sensor;

5) this light is synthetic by analyzer again;

6) this light is received the ac signal that will obtain and said reference signal than mutually by photodetector at last, thereby obtains the information of tested roll angle.

2, a kind of rolling angle measurement device, comprise a frequency stabilization transverse zeeman laser light source, semi-transparent semi-reflecting lens, analyzer, two photodetectors, phasometer, computing machine, it is characterized in that, also comprise 1/2nd wave plates, catoptron, this semi-transparent semi-reflecting lens is set on the optical axis of said transverse zeeman laser output terminal, on the transmission optical axis of this semi-transparent semi-reflecting lens, be vertically installed with 1/2nd wave plates, and on the reflection optical axis of this catoptron, be vertically installed with 1/2nd wave plates, analyzer and first photodetector successively; Be vertically installed with second photodetector on the reflection optical axis of this semi-transparent semi-reflecting lens, the input end of said phasometer links to each other with the output terminal of this first photodetector, second photodetector, and the output terminal of said phasometer links to each other with said computing machine.

3, rolling angle measurement device as claimed in claim 2 is characterized in that, also comprises the quarter-wave plate on the optical axis that is arranged between said semi-transparent semi-reflecting lens and 1/2nd wave plates.

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