CN103134442A - Detection method of aspherical surface shape - Google Patents

Abstract

Disclosed is a detection method of an aspherical surface shape. The detection method of the aspherical surface shape comprises the steps of manufacturing a reflective compensating mirror matched with an aspheric surface to be measured according to the aspheric surface to be measured, placing a standard mirror, the aspheric surface to be measured and the reflective compensating mirror in sequence in the direction in which a phase shifting interferometer outputs light beams, adjusting a light path, adjusting the distance between the aspheric surface to be measured and the reflective compensating mirror to obtain complete and clear interferometric fringes, and using the phase shifting interferometer for detecting the interferometric fringes so as to obtain surface shape information of the aspheric surface to be measured. The detection method of the aspherical surface shape has the advantages of being simple in operation, capable of enabling the detection of a heavy-calibre aspherical surface shape to be achieved easily and the like.

Description

The detection method of aspheric surface

Technical field

The present invention relates to the detection method in optical detection field, particularly a kind of aspheric surface.

Technical background

Traditional optical system generally adopts the sphere element to proofread and correct the designing requirement that various aberrations are realized optical system.System compares with spherical optics, aspheric use be improved system relative aperture, enlarge the advantages such as field of view angle, simplied system structure, reduced volume, this just makes aspheric application more and more extensive.But processing and the detection technique of non-spherical element are more more complicated than sphere element, and this has just proposed strict requirement to the machining precision of non-spherical element, thereby need accurate measuring method to realize that the face shape of non-spherical element is detected.

Known technology [1] utilizes calculating holographic element (being designated hereinafter simply as CGH) to realize the detection of aspheric surface.Utilizing calculation holographic to carry out zero compensation realizes aspheric detection, need to be for the special CGH of certain aspheric surface, when the aperture aspherical surface shape measurement, because the characteristic dimension of calculation holographic is less, so be difficult to realize the making of caliber high-precision hologram, the simultaneously making of heavy caliber CGH and debug and also have a lot of difficulties, fabrication cycle is very long, and manufacturing expense is expensive.

Known technology [2] design lens compensation mirror group recycling interferometer detects aspheric shape.The method can realize that aspheric quantification detects, and has improved accuracy of detection greatly.But needing to process some high-precision compensating glass in this lens compensation method realizes detecting, particularly when measuring large-caliber convex aspheric surface, the bore of these compensating glass need be greater than or equal to aspheric bore to be detected, so be difficult to realize Precision Machining, and the process-cycle is long, manufacturing expense is expensive, has so just indirectly increased the aspheric process-cycle, has greatly improved aspheric manufacturing expense.

Known technology [3] utilizes contactless laser interferometer to carry out aspheric surface and detects.The Verifire that U.S. ZYGO company produces ^TMAsphere is that a kind of non-contacting aspheric surface 3D measures laser interferometer, and its actual measurement range is subjected to the characteristic limitations of to be measured, and for the measurement of convex aspheric surface, many restrictive conditions is arranged especially.

Summary of the invention

The object of the invention is to overcome above-mentioned the deficiencies in the prior art, a kind of detection method of aspheric surface is provided.The method has simple to operate, is easy to realize the advantages such as aperture aspherical face shape detection.

Technical solution of the present invention is as follows:

A kind of detection method of aspheric surface is characterized in that, the method comprises the following steps:

1. make according to aspheric surface to be measured the reflection compensation mirror that matches: utilize optical design software (Zemax, CODEV etc.) optimal design to go out the parameter of described reflection compensation mirror, make through described aspheric light beam to be measured and return on former road after described reflection compensation mirror reflection, and utilize the parameter of described reflection compensation mirror to process on diamond lathe, complete described reflection compensation mirror;

2. put into successively standard mirror, aspheric surface to be measured and reflection compensation mirror in phase-shifting interferometer output beam direction;

3. adjust light path: the optical axis coincidence of adjusting the parallel beam of the axis of described standard mirror and described phase-shifting interferometer outgoing; Adjust the optical axis coincidence of described aspheric axis to be measured and phase-shifting interferometer outgoing beam; Adjust described reflection compensation mirror, make described reflection compensation mirror vertically put into light path, the light beam of described phase-shifting interferometer outgoing forms measuring beam through described standard mirror, and the light beam that returns through described standard mirror is called reference beam; Described measuring beam sees through described aspheric surface to be measured and returns along former road through described reflection compensation mirror reflection, and the reference beam that the measuring beam that this former road is returned and standard mirror return produces interference fringe in described phase-shifting interferometer;

4. the distance of adjusting between described aspheric surface to be measured and described reflection compensation mirror obtains complete interference fringe clearly, utilizes described phase-shifting interferometer to detect interference fringe, thereby obtains described aspheric shape information to be measured.

Compare with technology formerly, technique effect of the present invention is as follows:

1, can realize measurement to aperture aspherical face shape with a small-bore reflection compensation mirror; This reflection compensation mirror adopts diamond lathe processing, and convenient and swift, precision is high, and cost is low.

2, the inventive method is simple to operate, and is flexible, by designing the reflection compensation mirror of various shapes, can realize the measurement to various complex optical surfaces.

3, the present invention only uses a reflection compensation mirror, just can realize the interferometry of aperture aspherical face shape.The Ultra-precision diamond lathe has been applied in the manufacturing of high-accuracy optical element maturely at present, can process the optical surface of various shapes, the machining precision of its part has been controlled at sub-micrometer scale, and surface figure accuracy is better than 100nm, and surfaceness is better than 5nm.Adopt diamond lathe processing reflection compensation mirror to have easy to process, surface figure accuracy is high, the advantages such as low cost of manufacture.

Description of drawings

Fig. 1 is the schematic diagram of aspheric surface pick-up unit embodiment of the present invention

Fig. 2 is the schematic diagram of aspheric surface pick-up unit embodiment 1 of the present invention

Fig. 3 is the schematic diagram of aspheric surface pick-up unit embodiment 2 of the present invention, and described standard mirror is a sphere standard mirror

Fig. 4 is the schematic diagram of aspheric surface pick-up unit embodiment 2 of the present invention, and described standard mirror is a plane standard mirror

Fig. 5 is the schematic diagram of aspheric surface pick-up unit embodiment 3 of the present invention, and described aspheric surface to be measured is the off-axis aspheric surface of a concave surface

Fig. 6 is the schematic diagram of aspheric surface pick-up unit embodiment 3 of the present invention, and described aspheric surface to be measured is the off-axis aspheric surface of a convex surface

Embodiment

The invention will be further described below in conjunction with drawings and Examples, but should not limit protection scope of the present invention with this.

First see also Fig. 1, Fig. 1 is the schematic diagram of aspheric surface detection method of the present invention.

Embodiment 1

The structure of the embodiment of the present invention 1 as shown in Figure 1, 2, the reflection compensation mirror that described reflection compensation mirror is a concave surface, its concrete structure is as follows:

1. make according to aspheric surface 3 to be measured the reflection compensation mirror 4 that matches: utilize optical design software (Zemax, CODE V etc.) optimal design to go out the parameter of described reflection compensation mirror 4, make the light beam that sees through described aspheric surface 3 to be measured return on former road after described reflection compensation mirror 4 reflections, and utilize the parameter of described reflection compensation mirror 4 to machine on diamond lathe, described reflection compensation mirror 4;

2. put into successively standard mirror 2, aspheric surface to be measured 3 and reflection compensation mirror 4 in phase-shifting interferometer 1 output beam direction;

3. adjust light path: the optical axis coincidence of adjusting the parallel beam of the axis of described standard mirror 2 and 1 outgoing of described phase-shifting interferometer; Adjust the axis of described aspheric surface to be measured 3 and the optical axis coincidence of phase-shifting interferometer 1 outgoing beam; Adjust described reflection compensation mirror 4, make described reflection compensation mirror 4 vertically put into light path;

4. the light beam of described phase-shifting interferometer 1 outgoing forms measuring beam through described standard mirror 2, and the light beam that returns through described standard mirror 2 is called reference beam; Described measuring beam sees through described aspheric surface 3 to be measured and returns along former road through described reflection compensation mirror 4 reflections, and the reference beam that the measuring beam that this former road is returned and standard mirror 2 return produces interference fringe in described phase-shifting interferometer 1;

5. the distance of adjusting between described aspheric surface to be measured 3 and described reflection compensation mirror 4 obtains complete interference fringe clearly, utilizes described phase-shifting interferometer 1 to detect interference fringe, thereby obtains the face shape information of described aspheric surface to be measured 3.

The aspheric formula of expression is as follows in rectangular coordinate system (x, y, z):

$z=\frac{c\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}{1+\sqrt{1-(1+k)\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">c</figure-callout>}}^2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}}+{\mathrm{\&alpha;}}_1{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2+{\mathrm{\&alpha;}}_2{\mathrm{<figure-callout\; id="4"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^4+{\mathrm{\&alpha;}}_3{r}^6+{\mathrm{\&alpha;}}_4{r}^8+{\mathrm{\&alpha;}}_5{r}^{10}+{\mathrm{\&alpha;}}_6{r}^{12}+{\mathrm{\&alpha;}}_7{r}^{14}+{\mathrm{\&alpha;}}_8{r}^{16}$

Wherein,

C=1/R ₀, R ₀Be vertex curvature radius, k=-e ²Be secondry constants, a ₁, a ₂, a ₃... a ₈Be asphericity coefficient.

The formula of described aspheric surface to be measured 3 is as follows:

$z=\frac{c\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}{1+\sqrt{1-(1+k)\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">c</figure-callout>}}^2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}}$

Wherein, c=1/278.3, k=-1.17824

In the situation that known described aspheric surface 3 formula to be measured, the described reflection compensation mirror (4) that utilizes Zemax optics Software Design Optimization to match, the design parameter of described reflection compensation mirror 4 is as follows:

The expression formula that can obtain described reflection compensation mirror 4 according to the parameter of the described reflection compensation mirror 4 of above-mentioned design optimization is:

$z=\frac{c\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}{1+\sqrt{1-(1+k)\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">c</figure-callout>}}^2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}}+{\mathrm{\&alpha;}}_1{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2+{\mathrm{\&alpha;}}_2{\mathrm{<figure-callout\; id="4"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^4+{\mathrm{\&alpha;}}_3{r}^6+{\mathrm{\&alpha;}}_4{r}^8+{\mathrm{\&alpha;}}_5{r}^{10}+{\mathrm{\&alpha;}}_6{r}^{12}+{\mathrm{\&alpha;}}_7{r}^{14}+{\mathrm{\&alpha;}}_8{r}^{16}$

$=\frac{-0.0059\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}{1+\sqrt{1-1.9855*{10}^{-5}\&CenterDot;r^2}}-2.3096*{10}^{-8}{\mathrm{<figure-callout\; id="4"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^4+4.1532e*{10}^{-12}{r}^6+5.7540*{10}^{-16}{r}^8-9.2087*{10}^{-20}{r}^{10}$

By making reflection compensation mirror 4 described above, adjust simultaneously the distance L between described aspheric surface to be measured 3 and described reflection compensation mirror 4, make the distance between them satisfy

L＞f

Wherein, f represents picture side's focal length of described aspheric surface to be measured (3).

So just, can realize the face shape of described aspheric surface 3 to be measured is detected.

Embodiment 2

The structure of the embodiment of the present invention 2 as shown in Fig. 3,4, the reflection compensation mirror that described reflection compensation mirror is a convex surface, its concrete structure is as follows:

1. make according to aspheric surface 3 to be measured the reflection compensation mirror 4 that matches: utilize optical design software (Zemax, CODEV etc.) optimal design to go out the parameter of described reflection compensation mirror 4, make the light beam that sees through described aspheric surface 3 to be measured return on former road after described reflection compensation mirror 4 reflections, and utilize the parameter of described reflection compensation mirror 4 to process on diamond lathe, complete described reflection compensation mirror 4;

2. put into successively standard mirror 2, aspheric surface to be measured 3 and reflection compensation mirror (4) in phase-shifting interferometer 1 output beam direction;

3. adjust light path: the optical axis coincidence of adjusting the parallel beam of the axis of described standard mirror 2 and 1 outgoing of described phase-shifting interferometer; Adjust the axis of described aspheric surface to be measured 3 and the optical axis coincidence of phase-shifting interferometer 1 outgoing beam; Adjust described reflection compensation mirror 4, make described reflection compensation mirror 4 vertically put into light path;

4. the light beam of described phase-shifting interferometer 1 outgoing forms measuring beam through described standard mirror 2, and the light beam that returns through described standard mirror 2 is called reference beam; Described measuring beam sees through described aspheric surface 3 to be measured and returns along former road through described reflection compensation mirror 4 reflections, and the reference beam that the measuring beam that this former road is returned and standard mirror 2 return produces interference fringe in described phase-shifting interferometer 1;

5. the distance of adjusting between described aspheric surface to be measured 3 and described reflection compensation mirror 4 obtains complete interference fringe clearly, utilizes described phase-shifting interferometer 1 to detect interference fringe, thereby obtains the face shape information of described aspheric surface to be measured 3.

The aspheric formula of expression is as follows in rectangular coordinate system (x, y, z):

$z=\frac{c\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}{1+\sqrt{1-(1+k)\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">c</figure-callout>}}^2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}}+{\mathrm{\&alpha;}}_1{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2+{\mathrm{\&alpha;}}_2{\mathrm{<figure-callout\; id="4"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^4+{\mathrm{\&alpha;}}_3{r}^6+{\mathrm{\&alpha;}}_4{r}^8+{\mathrm{\&alpha;}}_5{r}^{10}+{\mathrm{\&alpha;}}_6{r}^{12}+{\mathrm{\&alpha;}}_7{r}^{14}+{\mathrm{\&alpha;}}_8{r}^{16}$ Wherein,

C=1/R ₀, R ₀Be vertex curvature radius, k=-e ²Be secondry constants, a ₁, a ₂, a ₃... a ₈Be asphericity coefficient.

The formula of described aspheric surface to be measured 3 is as follows:

$z=\frac{c\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}{1+\sqrt{1-(1+k)\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">c</figure-callout>}}^2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}}$

Wherein, c=1/278.3, k=-1.17824

In the situation that known described aspheric surface 3 formula to be measured, the described reflection compensation mirror 4 that utilizes Zemax optics Software Design Optimization to match, the design parameter of described reflection compensation mirror 4 is as follows:

The expression formula that can obtain described reflection compensation mirror (4) according to the parameter of the described reflection compensation mirror (4) of above-mentioned design optimization is:

$z=\frac{c\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}{1+\sqrt{1-(1+k)\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">c</figure-callout>}}^2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}}+{\mathrm{\&alpha;}}_1{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2+{\mathrm{\&alpha;}}_2{\mathrm{<figure-callout\; id="4"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^4+{\mathrm{\&alpha;}}_3{r}^6+{\mathrm{\&alpha;}}_4{r}^8+{\mathrm{\&alpha;}}_5{r}^{10+}{\mathrm{\&alpha;}}_6{r}^{12}+{\mathrm{\&alpha;}}_7{r}^{14}+{\mathrm{\&alpha;}}_8{r}^{16}$

$=\frac{0.0063\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="DEST\_PATH\_HDA00003001384500011.png,DEST\_PATH\_HDA00003001384500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}{1+\sqrt{1-1.6377*{10}^{-4}\&CenterDot;r^2}}-1.1239*{10}^{-7}{r}^4-2.9793*{10}^{-12}{r}^6-1.0024*{10}^{-15}{r}^8$

By making reflection compensation mirror 4 described above, adjust simultaneously the distance between described aspheric surface to be measured 3 and described reflection compensation mirror 4, make the distance between them satisfy

L＜f

Wherein, f represents picture side's focal length of described aspheric surface to be measured 3.

So just, can realize the face shape of described aspheric surface 3 to be measured is detected.

Embodiment 3

The structure of the embodiment of the present invention 3 is as shown in Fig. 5,6, and method of the present invention also can realize the face shape of off-axis aspheric surface is detected, and its concrete structure is as follows:

1. make according to aspheric surface 3 to be measured the reflection compensation mirror 4 that matches: utilize optical design software (Zemax, CODEV etc.) optimal design to go out the parameter of described reflection compensation mirror 4, make the light beam that sees through described aspheric surface 3 to be measured return on former road after described reflection compensation mirror 4 reflections, and utilize the parameter of described reflection compensation mirror 4 to process on diamond lathe, complete described reflection compensation mirror 4;

2. put into successively standard mirror 2, aspheric surface to be measured 3 and reflection compensation mirror 4 in phase-shifting interferometer 1 output beam direction;

3. adjust light path: the optical axis coincidence of adjusting the parallel beam of the axis of described standard mirror 2 and 1 outgoing of described phase-shifting interferometer; Adjust the axis of described aspheric surface to be measured 3 and the optical axis coincidence of phase-shifting interferometer 1 outgoing beam; Adjust described reflection compensation mirror 4, make described reflection compensation mirror 4 vertically put into light path;

4. the light beam of described phase-shifting interferometer 1 outgoing forms measuring beam through described standard mirror 2, and the light beam that returns through described standard mirror 2 is called reference beam; Described measuring beam sees through described aspheric surface 3 to be measured and returns along former road through described reflection compensation mirror 4 reflections, and the reference beam that the measuring beam that this former road is returned and standard mirror 2 return produces interference fringe in described phase-shifting interferometer 1;

5. the distance of adjusting between described aspheric surface to be measured 3 and described reflection compensation mirror 4 obtains complete interference fringe clearly, utilizes described phase-shifting interferometer 1 to detect interference fringe, thereby obtains the face shape information of described aspheric surface to be measured 3.

Claims (1)

1. an aspheric surface testing method, is characterized in that the method comprises the following steps:

1. make according to aspheric surface to be measured (3) the reflection compensation mirror (4) that matches:

Utilize the optical design software optimal design to go out the parameter of described reflection compensation mirror (4), make the light beam that sees through described aspheric surface to be measured (3) return on former road after described reflection compensation mirror (4) reflection, utilize the parameter of described reflection compensation mirror (4) to process described reflection compensation mirror (4) on diamond lathe;

2. put into successively standard mirror (2), aspheric surface to be measured (3) and reflection compensation mirror (4) in phase-shifting interferometer (1) output beam direction;

3. adjust light path: the optical axis coincidence of adjusting the parallel beam of the axis of described standard mirror (2) and described phase-shifting interferometer (1) outgoing; Adjust the axis of described aspheric surface to be measured (3) and the optical axis coincidence of phase-shifting interferometer (1) outgoing beam; Adjust described reflection compensation mirror (4), make described reflection compensation mirror (4) vertically put into light path, the light beam of described phase-shifting interferometer (1) outgoing forms measuring beam through described standard mirror (2), and the light beam that returns through described standard mirror (2) is called reference beam; Described measuring beam sees through described aspheric surface to be measured (3) and returns along former road through described reflection compensation mirror (4) reflection, and the reference beam that the measuring beam that this former road is returned and standard mirror (2) return produces interference fringe in described phase-shifting interferometer (1);

4. the distance of adjusting between described aspheric surface to be measured (3) and described reflection compensation mirror (4) obtains complete interference fringe clearly, utilize described phase-shifting interferometer (1) to detect interference fringe, thereby obtain the face shape information of described aspheric surface to be measured (3).

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