CN86106782A - Comparative optical analytic method and laser optical analyser therefor - Google Patents

Abstract

The present invention is by reference light paths light intensity I., cross-polarized light light intensity I _Or parallel polarisation light intensity I _‖Propose the formula of new calculating optical path difference, and invented new method of testing.Equipment provided by the present invention is little of 50 μ m microcells the measurement of physical optical parameters such as birefringence and absorbance.The present invention is again an optical microscope, not only can carry out quantitative test, describe isochromatic line the anisotropy and the absorbance of material microcell, isoclinic line and etc. the absorbance line, analyze its structure and morphology, carry out the low angle laser light scattering experiment, also can test the sample of thin and transparent sample and the big penetrability difference of thickness.Can be applicable to medical science, macromolecule, fields such as mineral crystal and polarization photoelasticity.

Description

On November 1st, 1984, Optical Society of America's publication " applied optics " (APPLIED OPTICS/Vol 23NO 21/1Novenmber 1984) has been delivered one piece of article, speak of a kind of advanced double refractive measurement and instrument thereof that be considered to, its method is to measure the vertical polarization light intensity L of laser earlier, measures the parallel polarization light intensity I of laser again ₁₁, press the optical path difference R that formula is obtained measured object:

｜R｜＝Nπ+2Tan ^-1 $\sqrt{I{}_1\mathrm{/\; I}{}_{\mathrm{11}}}$ Work as N=0,2,4 ... (1)

｜R｜＝（N+1）π-2Tan ^-1 $\sqrt{I{}_1\mathrm{/\; I}{}_{\mathrm{11}}}$

Work as N=1,3,5 ... (2)

Its structure is: a Guang Dian Zhuan Change device, LASER Light Source, polarizer, analyzer, display and a pen recorder.But this technology has following weak point: one is because of I ₁And I ₁₁Be actually the function of time, the device that is provided in test can't be at synchronization with I ₁And I ₁₁Measure simultaneously, therefore, the method can't get rid of with device because the different error that influence caused of power supply, environment etc. constantly.Its two this articles institute's extracting method and device are to utilize photon flux method to test, its as a result reality reflected the mean value of the full ken, the enlargement factor of optical microscope is the product of object lens and eyepiece enlargement factor, it is too high that the eyepiece enlargement factor can not be obtained by the restriction of numerical aperture of objective (NA), existing optical microscope enlargement factor generally has only 800～1000 times (not immersion oil enlargement factors), before not taking special measure, can't measure the small local light path difference of diameter less than the littler meticulousr zone of 1mm, the birefraction that can not depict sample more subtly distributes isolatedly.Its three value of can not determine path difference level preface N.

The objective of the invention is to solve measuring error, the solution point-to-point measurement problem that the laser instrument light-intensity variation causes, so that can reflect that the each point birefringence distributes, makes instrument have multiple function in the tiny area, as judging path difference level preface, describing isoclinic line, isochromatic line etc., absorbance line and carry out microstructure observation etc.Make instrument provided by the present invention become more complete optical analyser.

The present invention proposes a whole set of new measuring method, and method is drawn a kind of novel multi-use optical analytic method and laser optical analyser thus, and the present invention and equipment have produced the beyond thought effect of prior art, has formed a complete invention.

The present invention's feature on method is, introduces the 2nd light electricity and changes Change device 2 and form reference light paths, introduce the reference computing method, in order to the error that labile factor in the elimination system is brought, finishes accurate optical path difference and calculates; The present invention has introduced the notion of photon flux method resolution, adopts multiple eyepiece to improve the enlargement factor of eyepiece greatly in view of the above, thereby has improved the enlargement factor of instrument, and ken diameter is reduced greatly, reaches the purpose that improves photon flux method resolution greatly.Instrument proposed by the invention can be tested little microcell to 50 μ m, and the enlargement factor on the instrumental theory can also further improve, so that reach the level of 1～2 μ m; Introduce tracing and determine the each point principal direction of stress, determine isoclinic line, isochromatic line and path difference level preface.

The expression formula of well-known orthogonal polarized light light intensity is:

I ₁＝fKa ²（t）Sin ²(πR)/(λ)

The expression formula of parallel polarized light light intensity is:

I ₁₁＝fKa ²（t）Con ²(πR)/(λ)

A(t in the formula) being the amplitude of incident light light wave, is a function of time, and f is the constant relevant with reflection with the measured object light absorption, and K is the constant relevant with reflection to light absorption with the mirror group, and R is that optical path difference, the λ of measured object is incident light wave length.

Unpolarized does not see through the laser intensity I of sample ^' ₀(t) and the amplitude alpha of this light ' (t) satisfy following relation:

I ^′ ₀（t）＝k ₁a′ ²（t）

A ' (t) with a(t) amplitude of the light that is same light source by different light paths, experiment shows satisfies following rule between them:

A(t)=ka ' (t) k be the constant relevant with optical system

a ²（t）＝K ²a′ ²（t）＝K ₂a′ ²（t）

Be a ²(t)=(K ₂)/(K ₁) I ^' ₀(t)

So have

I ₁＝fK (K ₂)/(K ₁) I ^′ ₀（t）Sin ²(πR)/(λ)

If K is (K ₂)/(K ₁)=K ' (K ' be only and the optical system absorption and reflect relevant constant)

I then ₁=fK ' I ^' ₀(t) Sin ²(π R)/(λ)

Promptly $\mathrm{R\; =}\frac{\lambda }{\pi }\mathrm{A\; r\; c\; S\; i\; n}\sqrt{\frac{I_1\mathrm{(\; t\; )}}{{\mathrm{f\; K\prime <figure-callout\; id="0"\; label="I"\; filenames="86106782\_DRIMG4.png"\; state="\{\{state\}\}">I</figure-callout>}}_0\mathrm{\prime (\; t\; )}}}\mathrm{\dots \dots (3)}$

Can draw equally

$\mathrm{R\; =}\frac{\lambda }{\pi }\mathrm{A\; r\; c\; S\; i\; n}\sqrt{\mathrm{1\; -}\frac{I_{\mathrm{11}}\mathrm{(\; t\; )}}{{\mathrm{f\; K\prime <figure-callout\; id="0"\; label="I"\; filenames="86106782\_DRIMG4.png"\; state="\{\{state\}\}">I</figure-callout>}}_0\mathrm{\prime (\; t\; )}}}\mathrm{\dots \dots (4)}$

Because I in the formula ₁(t) and I ^' ₀(t) or I ₁₁(t) and I ^' ₀(t) measure from the first and second Guang Dian Zhuan Change devices simultaneously by computer automatic control system, the almost not free difference in centre, thereby the Stimulated Light light intensity has not reduced error because of the influence of fluctuations that the time brings, the said reference computing method of the present invention that Here it is.After equipment and sample were determined, f and K ' were amounts that no longer becomes, and can measure in advance.FK ' can draw with laxative remedy.

Select a kind of material, select the direction that birefraction is constant,, obtain the sample (but each sheet sample must be smooth even with thickness) that one group of thickness does not wait perpendicular to this direction section with even absorption system.In the sufficiently long time, ask the mean value I of three kinds of light intensity respectively to the time ₁(t), I ₁₁(t) and I ₀' (t).Because laser instrument light path stochastic distribution on time-base, its mean value is determined.After this simultaneous (3) and (4) formula then can be obtained the long-pending value of fK ' and come.When h is the thickness of sample, and have

Limf＝1

h→0

Therefore can make fK '-h figure (see figure 3)

FK ' when h=0=K ' obtains K '.

From method and apparatus proposed by the invention, adopt pointwise to force tracing into can determine preferably that principal direction of stress, isoclinic line, isochromatic line and the path difference level preface of measured object are next, the device that the present invention is constituted becomes multiduty optical analyser.The process of its realization is as follows: make certain point of sample be in extinction state in the cross-polarized light field, this moment, its principal direction of stress overlapped with the analyzing direction, thereby can determine the principal direction of stress of this point.Write down the I under this state ₁(t) ₀With I ^' ₀(t) ₀Can obtain its ratio r ₀, the coordinate of change objective table selects the i point of sample then can obtain the r that i is ordered _iValue is come.

r _i＝I ₁（t） _i/I ^′ ₀（t） _i……（5）

When objective table when optical axis direction is regulated continuously, if r _i-r _I-1＜ε (the enough little amount of ε for stipulating as required), the principal direction of stress that shows this point and do not become; Work as r _i-r _I-1During＜ε, then stop translation, and left or the moving angle [alpha] of turning right _i, make r _i(α _i)=minr _iIf the angle when initial is O ₀, then total angular displacement of objective table promptly this this principle stress with respect to the inclination angle O of analyzing direction _i

Q _i＝Q _i-1+ $\underset{\mathrm{i\; =\; 0}}{\overset{k}{\mathrm{\&Sigma;}}}$ α _iAs-45 °＜α _i＜45 ° ... (6) line that is unified into of the identical point in inclination angle is an isoclinic line.

Know by (3) formula

Promptly ${\mathrm{<figure-callout\; id="0"\; label="R"\; filenames="86106782\_DRIMG4.png"\; state="\{\{state\}\}">R</figure-callout>}}_0=\frac{\lambda }{\pi }\mathrm{A\; r\; c\; S\; i\; n}\sqrt{\frac{I_1\mathrm{(\; t\; )}}{{\mathrm{f\; K\prime <figure-callout\; id="0"\; label="I"\; filenames="86106782\_DRIMG4.png"\; state="\{\{state\}\}">I</figure-callout>}}_0\mathrm{\prime (\; t\; )}}}$ R ₀Be called half grade path difference formula

Obvious R≤(λ)/2

(λ)/2 are divided into some equal portions, 16 equal portions for example, then Yi Fen width item has (0～(λ)/32) for (λ)/32, and ((λ)/32～(2 λ)/32) ... ((15 λ)/32～(16 λ)/32) each segment is measured the R of each segment ₀, to R ₀Identical segment then has following table with prosign:

To after the whole audience test, can draw figure accordingly and come (see figure 6), each same-sign is unified into wire or banded line is isochromatic line among the figure.The present invention determines path difference level preface by laxative remedy: under white light, the null broad isochrome of choosing-R tape is determined path difference level preface with the quartz wedge that is carved with special scale.So-called special scale must be used device provided by the invention, is that unit is engraved on the quartz wedge with corresponding path difference value with the laser optical wavelength, is accurate to 0.5 grade.

The present invention structurally forms oneself characteristic alone, its structure (see figure 1) is made up of the adjustable objective table of 3, one white light sources of LASER Light Source that do not expand bundle 1, two Guang Dian Zhuan Change devices 2 and 5,9, one group of multi-usage mirror group 4, display 6, pen recorder 7 and controller 8.The unpolarized that its 2nd light electricity commentaries on classics Change device 2 receives the lasing light emitters ejaculation is not passed the light signal of sample, forms reference light paths.Multi-usage mirror group 4(sees Fig. 2) form by objective table 9, polarizer 10, wave plate 11, sample 12, object lens 13, wave plate 14, quartz wedge 15, analyzer 16, first eyepiece 17, second eyepiece 18 and micro-attachable mechanical stage 19.

What occupy critical role in the present invention is to have improved photon flux method resolution greatly, has promptly improved the enlargement factor of optical frames group greatly.The present invention has specific (special) requirements to object lens 13, the first eyepieces 17 and second eyepiece 18, requires the enlargement factor of the mirror group of its composition to be greater than or big greater than the enlargement factor that the resolution of microscope limited, and proposes the notion that this imagination is based on so-called photon flux method resolution.The so-called resolution of light intensity test method (being called for short photon flux method resolution) is different from the usually said resolution of microscope, it is not meant in the ken distinguishable near 2 distance, because photon flux method reflects the mean value of light signal in the tested ken, so its resolution is when the diameter of the minimum tested ken that is considered as reaching, we are referred to as photon flux method resolution temporarily, obviously photon flux method resolution depends on the enlargement factor of optical frames group, and the microscope enlargement factor will be subjected to the restriction of numerical aperture of objective (NA), can not obtain too high, yet same object lens, photon flux method resolution is not subjected to the restriction of numerical aperture of objective (NA), the enlargement factor of its eyepiece can improve greatly, till the photon flux method resolution limit that object lens allowed.The a of Fig. 4 figure, dotted line is fractographic zone, and establishing the resolution of microscope is 2 μ m, and as improving the eyepiece enlargement factor again, resolution still can not improve, just zooming.This adjusts the telescope to one's eyes and observes is nonsensical.But concerning the light intensity test method, improving enlargement factor reduces ken diameter, as scheming after a is amplified to figure b, the ken can be contracted to the territory, garden shown in the dotted line among the b figure relatively, at this moment instrument is only gathered the optical information from one of Saint Andrew's cross fork " * " arm part, rather than to scheming the amplification of the whole ken of a.Be amplified to figure b by figure a,,, but reached and measured the purpose that Saint Andrew's cross is pitched each local physical optics character respectively the photon flux method test though the observation that adjusts the telescope to one's eyes fails to tell more small details.Instrument provided by the invention, enlargement factor can reach 10080 times, corresponding ken diameter is 50 μ m, thereby can be in the yardstick of 1mm, do not carry out the test of 20 points overlappingly, can be used for the measurement (as the three-dimensional slice photoelastic analysis of crackle light end, the photoelastic analysis of tooth slice etc.) that the tiny area birefringence distributes.

The present invention proposes in optic test can widespread usage reference formula method, for solving in the present optic test the ubiquitous environment change error of making an uproar, the simple method and apparatus of an actual effect is provided, only go ahead, all determine fringe value by means of compensator with regard to traditional photoelasticity stress analysis instrument and birefringence instrument.Nearest Peking University has released a kind of automatic photoelastic device (CN85100284B) employing can carry out the optical modulation piezoelectric crystal, be added on the voltage at piezoelectric crystal two ends during according to the compensation extinction state, determine the optical path difference or the fringe value of sample, thereby replaced the mineral crystal compensator.But this method has following drawback still based on certain compensator: (1) depends on specific material, general expensive and difficult acquisition of this material.(2) Ce Shi precision is subjected to the restriction of compensating device precision.Optical Society of America's " applied optics " though the article that Applied Optics delivers in November, 1984 not by compensator, the ken is big, can not observe the optical path difference of tiny area, and the bigger environment change error of making an uproar is arranged, and is only limited to the measurement of optical path difference in half grade.One piece of delivering of Northwestern Polytechnical University in 1985 is entitled as " with the birefraction of laser determination superpolymer " literary composition, owing to used polarizing microscope, U.S.'s device is improved to some extent, but still can not get rid of above deficiency.Controller of the present invention can adopt computing machine, and the collection of computing machine can provide I simultaneously ^' ₀(t) and I ₁(t) (or I ₁₁(t)), and come from connecing the optical path difference of calculating sample, make the speed that the whole audience is carried out sweep test only be subject to the speed of computer sampling according to formula provided by the invention.

Compare with prior art, the present invention has following advantage:

1. measure the birefraction of material with photon flux method, being acknowledged as it has very high precision.But because the influence of fluctuations of light source intensity reduces its actual measuring accuracy greatly.The present invention makes measuring accuracy be higher than the prior art level owing to eliminated the influence of light-intensity variation.The amplitude of its raising, by laser instrument that is adopted and environment for use conditional decision, when adopting that temperature, voltage all do not have fluctuation with the helium-neon laser of external constant current source, the present invention can make measuring accuracy improve 20% at least.

2. existing light intensity test method does not relate to the problem of resolution as yet.The fringe value that needs each point on the test sample plane in the photoelasticity stress analysis, but the real resolving accuracy of prior art is inferior to the millimeter magnitude.The present invention can bring up to resolution the micron number magnitude, the birefringence that therefore can solve a series of microsections such as three-dimensional photoelasticity section, biologic slice, mineral crystal section and macromolecular material section distributes, and can describe their isochromatic line, isoclinic line field, the grade luminosity field of line etc.

3. the existing method of utilizing light intensity to survey birefraction can't be judged path difference level preface.Those can but can not accurately provide the optical path difference of each point by the photo-elastic instrument that whole audience photography provides isochromatic line.And photo-elastic instrument can't only provide pure isoclinic line (adding analysis by hand can describe) with instrument.Instrument provided by the present invention has the path difference of judgement level preface, describes pure isochromatic line and pure multiple functions such as isoclinic line.The application of method provided by the present invention has the future of extensive exploitation, the purposes of device provided by the present invention, and further exploitation also awaits.Except that above-mentioned advantage, Instrument structure of the present invention also reaches following beyond thought effect.

1. the reference light paths that two Guang Dian Zhuan Change devices provide, except having improved measuring accuracy, also making instrument carry out continuous pointwise test becomes possibility.As previously mentioned, prior art is being measured I ₁₁And I ₁The time, must not accident after intact one, change polarization conditions and survey another again, whole test can only be carried out with surveying the mode of stopping.And the present invention can the while test I ^' ₀(t) and I ₁(t) (or test I ^' ₀(t) and I ₁₁(t)) two signals, measure simultaneously then can guarantee to test improved efficient continuously widely.Make microcomputer robotization on line operation test become possibility.In addition, because the present invention has well eliminated the influence of light source fluctuation, so instrument can select the relatively poor cheap laser instrument of light stability for use in design, also allows to place the stable inadequately general occasion of environmental factor (temperature, voltage etc.) to use in instrument.

2. the present invention adopts and not to expand Shu Jiguang and also produced some good effects:

A must not expand bundle, and instrument is simplified.

B does not expand Shu Jiguang not by beam split, and the few concentration of energy of energy loss can penetrate big thickness and low-transmittance material, has widened the range of application of instrument.Experiment shows, but the present invention's Thickness Measurement by Microwave scope is the 100A ° of transparent sample to the 10mm.Can be used for thicker film and the sections of the high leviathan of low-transmittance such as PVC, PET, nylon, be used for the test of opaque material sections such as tooth, mineral.

3. instrument provided by the present invention, adopt microscope primary elements such as object lens, eyepiece, so instrument of the present invention is except that being used as birefringence instrument or photo-elastic instrument, but also general optical microscope of double as and polarizing microscope use is convenient to researcher the multiple physical property of the same area is carried out optical analysis, as the birefringence analysis, penetrability is analyzed, and structure observation is by changing enlargement factor, can select ken diameter at sample size and test request, to obtain the average light signal of desired zone.Instrument provided by the present invention also can carry out the low angle laser light scattering experiment and even take.The essence that helps the integrated survey material.

4. its structure of instrument of the present invention's proposition need not adopt any large diameter optical mirror slip, and used element is domestic commercially available prod, so low apparatus construction cost is easily manufactured, the very strong market competitiveness is arranged.

Embodiments of the invention such as Fig. 5 are by forming with the lower part: white light source 1, second light electricity commentaries on classics Change device 2, the lasing light emitter 3 that does not expand bundle, first light electricity commentaries on classics Change device 5, polarizer 10, wave plate 11, objective table 9, sample 12, micro-attachable mechanical stage 19, object lens 13, wave plate 14, quartz wedge 15, analyzer 16, first eyepiece 17, second eyepiece 18, light damping plate 21 and reflective mirror 20.Select for use the quantity of reflective mirror to depend on light path, if light path cut-off then reflective mirror can be removed.To doing following explanation with the performance of upper-part:

White light source 1 selects for use 250 watts of bromine calcium lamps that two location statuss are arranged, and when it places the light path position, needs to plug in a light barrier with shielding laser at its afterbody, should guarantee unobstructed ground of laser beam beam incident optical mirror group when it withdraws from light path.LASER Light Source 3 is selected for use greater than 3 milliwatt helium-neon lasers, because the ken diameter of instrument is very little, laser does not expand bundle.Objective table 9 and micro-attachable mechanical stage 19 can be done the coordinate adjustment, can be parallel to light beam and perpendicular to the motion and the rotation of beam direction; Its displacement can be passed through displacement transducer, by robot control system(RCS) control, shows and record.Object lens 13 are selected 63 times of object lens for use, and first eyepiece 17 is selected 10 times of eyepieces for use, and second eyepiece 18 is selected 16 times of eyepieces for use; Quartz wedge 15 is for having with optical maser wavelength the quartz wedge of the path difference level preface value scale that is unit.Select plain mode for use with lower member in the embodiment of the invention, promptly display 6 can be with microampere meter or inspection statistics, and registering instrument 7 can be with self-recording device also available camera.

Claims (9)

1,1984, Optical Society of America's magazine " applied optics " (APPLIEDOPTICS/Vo123No21/1Novenmber1984) was spoken of a kind of advanced double refractive measurement and instrument thereof that be considered to, and its method is to measure the vertical polarization light intensity I of laser earlier _⊥, measure the parallel polarization light intensity I of laser again ₁₁, press the optical path difference R that formula is obtained measured object:

|R|=Nπ+2Tan ^-1 $\sqrt{I{}_{┴}\mathrm{/\; I}{}_{\mathrm{11}}}$ N=0,2,4,……（1）

｜R|=(N+1)π-2Tan ^-1 $\sqrt{I{}_{┴}\mathrm{/\; I}{}_{\mathrm{11}}}$ N=1,3,5,……（2）

Its structure is: a photoelectric commutator, LASER Light Source, polarizer, analyzer, display and a pen recorder.

The feature of the present invention on method is, the error of bringing for each labile factor in the elimination system, introduce the reference computing method and calculate optical path difference, introduce photon flux method resolution method for measuring microcell (diameter is the zone of micron number magnitude) optical path difference, and introduce tracing thus and determine each point principal direction of stress, isoclinic line, isochromatic line and path difference level preface.

2,, it is characterized in that the reference computing method are to pass through I according to the said invention of claim 1 ^' ₀(t), I _⊥(t) (or I ₁₁(t)) calculate optical path difference

$\mathrm{R\; =}\frac{\lambda }{\pi }\mathrm{a\; r\; c\; S\; i\; n}\sqrt{\frac{I_{┴}\mathrm{(\; t\; )}}{{\mathrm{f\; K\prime I}}_0\mathrm{\prime (\; t\; )}}}\mathrm{\dots \dots (3)}$

$\mathrm{R\; =}\frac{\lambda }{\pi }\mathrm{a\; r\; c\; S\; i\; n}\sqrt{\mathrm{1\; -}\frac{I_{\mathrm{11}}\mathrm{(\; t\; )}}{{\mathrm{f\; K\prime I}}_0\mathrm{\prime (\; t\; )}}}\mathrm{\dots \dots (4)}$

In the formula: I _⊥(t) be that light electricity changes the light intensity that the Change device is surveyed the laser vertical polarized light;

I ₁₁(t) be that light electricity changes the light intensity that the Change device is surveyed the laser parallel polarized light;

I ^' ₀(t) be that the 2nd light electricity changes the laser intensity that the Change device is surveyed;

λ is the wavelength of laser wave;

K ' is with the optical system absorption and reflects relevant constant;

F is with the measured object absorption and reflects relevant constant.

3, according to the said invention of claim 1, it is characterized in that photon flux method resolution is for observing small local light path difference (diameter is micron number magnitude zone) break through the restriction of micro-amplification to numerical aperture of objective (NA), forming high-amplification-factor mirror group by object lens 13, first eyepiece 17 and second eyepiece 18 and realize.

4, according to the said invention of claim 1, it is characterized in that determining the direction and the isoclinic line of principle stress with tracing, its method is to make certain point of sample be in extinction state in the cross-polarized light field, and this moment, its principal direction of stress overlapped with the analyzing direction, thereby determines the principal direction of stress of this point down.Write down the I under this state _⊥(t) ₀With I ^' ₀(t) ₀Obtain ratio r _oChange the coordinate of objective table, select different i points then can obtain different r _iValue is come:

r _i＝I _⊥（t） _i/I ^′ ₀（t） _i……（5）

When objective table when optical axis direction is regulated, as | r _i-r _I-1|＜ε (the enough little amount of ε for stipulating as required), the principal direction of stress that shows this point and do not become.When | r _i-r _I-1| during 〉=ε, then stop translation, and left or the moving angle [alpha] of turning right _i, make r _i(α _i)=minr _iIf the angle when initial is O ₀, then total angular displacement of objective table promptly this this principal direction of stress with respect to the inclination angle of analyzing direction with respect to the analyzing direction

O _i＝O _i-1+ $\underset{\mathrm{i\; =\; 1}}{\overset{k}{\mathrm{\&Sigma;}}}$ α _i，-45°＜α _i＜45°……（6）

The line that the identical point in inclination angle is unified into is an isoclinic line.

5,, it is characterized in that the isochromatic line that can accurately describe the whole audience with the optical path difference formula in half grade comes, as using according to claim 1 or 2 said inventions

$R_0=\frac{\lambda }{\pi }\mathrm{a\; r\; c\; S\; i\; n}\sqrt{\frac{\mathrm{I\; (\; t\; )}}{{\mathrm{f\; K\prime I}}_0\mathrm{\prime (\; t\; )}}}$

Then have:

R ₀Be called the path difference formula in half grade, R is promptly arranged ₀≤ (λ)/2.(λ)/2 are divided into some equal portions, 16 equal portions for example, a width is (λ)/32, and (0～(λ)/32) are then arranged, ((λ)/32～(2 λ)/32 ... ((15 λ)/32～(16 λ)/32).Measure the R of each point on the sample, in one's duty R such as same represented that with prosign following table is then arranged:

To be segmented into the Building X mark, be the Building Y mark with corresponding symbol, can make Fig. 6, the line that each same-sign among the figure is unified into wire or band shape is isochromatic line.

6, according to the said invention of claim 5, it is characterized in that under white light the null broad isochrome of choosing-R tape carries out delustring with the quartz wedge that is carved with special scale, can read the path difference level preface of this line from the quartz wedge and come.

7, the present invention's feature structurally is: by the adjustable objective table of a LASER Light Source that does not expand bundle 3, white light source 1, two Guang Dian Zhuan Change devices 2 and 5,9, one group of multi-use optical mirror group 4, display 6, pen recorder 7 and controller 8 are formed.

8,, it is characterized in that the unpolarized of the 2nd light electricity commentaries on classics Change device 2 reception lasing light emitters ejaculations sees through the light signal of sample, forms reference light paths according to the said invention of claim 7.

9,, it is characterized in that one group of multi-use optical mirror group 4 its structure is made up of objective table 9, polarizer 10, wave plate 11, sample 12, object lens 13, wave plate 14, quartz wedge 15, analyzer 16, first eyepiece 17, second eyepiece 18 and micro-attachable mechanical stage 19 according to the said invention of claim 7.

10, according to claim 7 or 9 said inventions, it is characterized in that the quartz wedge scale is carved into by the following method: using device provided by the invention, with corresponding path difference value, is that unit is engraved on the quartz wedge with the wavelength of laser wave, is accurate to 0.5 grade.

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