CN103697807B - A kind of double-frequency laser displacement and angle interferometer - Google Patents

Abstract

A dual-frequency laser displacement and angle interferometer, including a frequency-stabilized dual-frequency laser, a partial reflection beam splitter, an interference component, an octave component and a target mirror component arranged in sequence from left to right, and also includes a first photoelectric conversion unit, a second Two photoelectric conversion units, a third photoelectric conversion unit and a phase measurement module connected thereto; the interference assembly includes a top-down first corner cube, a first quarter-wave plate, a non-polarizing beam splitter and a first polarization Dichroic prism; multiplier component includes a second corner cube prism, a second polarization beam splitter and a reflector from top to bottom; the target mirror assembly includes a corner cube clamping base and a third corner cube bonded therein and The fourth corner cube; the present invention solves the problem of no displacement information by increasing part A of the interference component; by improving part B of the multiplier component, the displacement of a single corner cube is an optical four subdivision, so the angle measurement is an optical four subdivision. The displacement measurement is optical eight subdivision, and the measurement resolution is improved.

Description

A dual-frequency laser displacement and angle interferometer

technical field

The invention belongs to the field of precision displacement measurement and angle measurement, in particular to a dual-frequency laser displacement and angle interferometer.

Background technique

When measuring the multi-axis motion error of the guide rail of high-precision CNC machine tools, the dual-frequency laser interferometer goniometer has been widely used due to its advantages of high resolution, high precision, high speed, good repeatability and large measuring range.

The schematic diagram of the angle measurement principle of the traditional dual-frequency laser interferometer is shown in Figure 1. The dual-frequency orthogonally polarized laser emitted by the dual-frequency laser interferometer is divided into two beams according to the polarization direction by the polarization beam splitter 1, and the polarization state is parallel to YZ The light with plane frequency f ₁ passes through polarizing beam splitter 1 and shoots to corner cube 3; the light whose polarization state is parallel to the XY plane and frequency f ₂ is reflected by polarizing beam splitter 1 and then goes through mirror 2 and then shoots to corner cube 4 . The light beams reflected by the two corner cubes are respectively received by the photoelectric receiver 5, and the double corner cube group A is placed on the measured object. When the measured object moves back and forth without swinging, Δf ₁ -Δf ₂ in the beat frequency is Constant, the angle output value does not change. If the corner cube prism is tilted by an angle of θ around the X axis during the movement, the two corner cube prisms will produce a relative displacement Δ in the direction of the Y axis, so the angle change obtained is:

$\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; sin</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\frac{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}}{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; sin</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\frac{<span\; class="notranslate">\; \&Integral;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; dt</span>}}{\mathrm{<span\; class="notranslate">\; L</span>}}$

In the formula: L is the distance between the corners of the corner cubes 3 and 4.

This solution has no optical subdivision, and the fundamental problem is that the displacement information corresponding to the current angle cannot be obtained. When measuring the multi-axis motion error of the guide rail of a high-precision CNC machine tool, the angular error cannot be accurately located on the guide rail.

Contents of the invention

In order to solve the above problems in the prior art, the object of the present invention is to provide a dual-frequency laser displacement and angle interferometer, which solves the problem that the existing dual-frequency laser interferometer has no displacement information, and has high measurement sensitivity and compact mechanism. , easy to assemble, and can be widely used in precision measurement of geometric quantities.

To achieve the above object, the present invention adopts the following technical solutions:

A dual-frequency laser displacement and angle interferometer, including a frequency-stabilized dual-frequency laser 1, a partially reflective beam splitter 2, an interference component A, a multiplier component B and a target mirror component C arranged in sequence from left to right, and also includes a first A photoelectric conversion unit D1, a second photoelectric conversion unit D2, a third photoelectric conversion unit D3, and a phase measurement module 14 connected to the first photoelectric conversion unit D1, the second photoelectric conversion unit D2 and the third photoelectric conversion unit D3;

The output laser of the frequency-stabilized dual-frequency laser ₁ is an orthogonally polarized frequency-stabilized _dual -frequency laser, and the output lights are f1 light whose polarization state is parallel to the YZ plane, namely P light, and f2 light whose polarization state is parallel to the XY plane, namely S light;

The partially reflective beamsplitter 2 is composed of two right-angle prisms bonded along the slope, and a non-polarizing partially reflective beam-splitting film is coated on the slope of the right-angle prism;

The interference assembly A includes a first corner cube prism 3, a first quarter-wave plate 4, a non-polarizing beam splitting prism 5 and a first polarizing beam splitting prism 6 arranged in sequence from top to bottom, and the non-polarizing beam splitting prism 5 and the first polarizing beam splitter prism 6 are all formed by bonding two rectangular prisms along the inclined plane, the upper surface of the first quarter wave plate 4 is bonded to the bottom surface of the first corner cube prism 3, and the lower surface is bonded to the bottom surface of the first corner cube prism 3. The upper right-angled surface of the non-polarizing beam-splitting prism 5, the lower right-angled surface of the non-polarizing beam-splitting prism 5 is bonded to the upper right-angled surface of the first polarizing beam-splitting prism 6; There is a non-polarized beam-splitting film, reaching a splitting ratio of 50:50, and a polarized beam-splitting film is coated on the slope of the rectangular prism of the first polarized beam-splitting prism 6;

The multiplier component B includes a second corner cube prism 7, a second polarization beam splitter prism 8 and a reflector 10 arranged in sequence from top to bottom, and the second polarization beam splitter prism 8 is composed of two right-angle prisms bonded along an inclined plane , the reflector 10 is a right-angle trapezoidal prism coated with a depolarized total reflection film on the slope, and its slope is parallel to the slope of the right-angle prism of the second polarization beam splitter prism 8, and the top of the second polarization beam splitter prism 8 The right-angled surface is bonded to the bottom surface of the second corner cube prism 7, and the lower right-angled surface is bonded to the upper right-angled surface of the reflector 10, and the inclined surface of the right-angled prism of the second polarization beam splitter prism 8 is coated with a polarization beam splitting film. Including the second quarter-wave plate 9 bonded to the right end surface of the second polarization beam splitter prism 8 and mirror 10;

The target mirror assembly C includes a corner cube holding base 13, and a third corner cube 11 and a fourth corner cube 12 bonded to the inside of the corner cube holding base 13;

Three corner cube surfaces of the first corner cube prism 3, the second corner cube prism 7, the third corner cube prism 11 and the fourth corner cube prism 12 are coated with a total reflection film;

The angle between the optical axis of the first quarter-wave plate 4 and the second quarter-wave plate 9 and the polarization direction of the f1 light emitted by the frequency-stabilized dual-frequency laser ₁ is 45°;

The positional relationship of the above components meets the following requirements:

The f1 light emitted by the frequency-stabilized dual-frequency laser ₁ , that is, the P light, passes through the partial reflection beam splitter 2, and a part of the f1 light is reflected to the _first photoelectric conversion unit D1, and the transmitted light of the f1 light is split by the non-polarizing beam splitter 5, etc. The two beams of light of light intensity are reflected light and transmitted light; the reflected light passes through the first quarter-wave plate 4 successively, and is formed by the first corner cube prism 3, the first quarter-wave plate 4, and the non-polarizing beam splitter 5 , enter the third photoelectric conversion unit D3 after the first polarizing beam splitting prism 6; the transmitted light passes through the second polarizing beam splitting prism 8, the second quarter wave plate 9 successively, and is passed through the third corner cube prism 11, the second quarter wave plate Wave plate 9, the second polarizing beamsplitter prism 8, the second corner cube prism 7, the second polarizing beam splitting prism 8, the second quarter wave plate 9, the third corner cube prism 11, the second quarter wave plate 9. The second polarizing beam-splitting prism 8, the non-polarizing beam-splitting prism 5, and the first polarizing beam-splitting prism 6 enter the second photoelectric conversion unit D2;

The f2 light emitted by the frequency-stabilized dual-frequency laser 1, that is, the S light, passes through the partial reflection beam splitter 2, and a part of the f2 light is reflected to the first photoelectric conversion unit D1, and the transmitted light of the f2 light is divided into equal light intensity by the non-polarizing beam splitter 5 The two beams of light are reflected light and transmitted light; the reflected light passes through the first quarter-wave plate 4 successively, and is formed by the first corner cube prism 3, the first quarter-wave plate 4, the non-polarizing beam splitter 5, the first Enter the second photoelectric conversion unit D2 after a polarizing beam splitting prism 6; The transmitted light passes through the second polarizing beam splitting prism 8, reflector 10, the second quarter wave plate 9 successively, by the fourth corner cube prism 12, the second four One-quarter wave plate 9, reflecting mirror 10, the second polarization beam splitter prism 8, the second corner cube prism 7, the second polarization beam splitting prism 8, reflecting mirror 10, the second quarter wave plate 9, by the fourth angle The axicon prism 12, the second quarter wave plate 9, the mirror 10, the second polarizing beam splitting prism 8, the non-polarizing beam splitting prism 5, and the first polarizing beam splitting prism 6 enter the third photoelectric conversion unit D3.

The non-polarized partially reflective spectroscopic film coated on the inclined surface of the partial reflective beam splitter 2 reaches a splitting ratio of 10:90.

The frequency-stabilized dual-frequency laser 1, the partially reflecting beam splitter 2, components A and B are fixed in position, and component C is installed on the object to be measured and moves with the object to be measured.

The first photoelectric conversion unit D1, the second photoelectric conversion unit D2 and the third photoelectric conversion unit D3 convert the optical signal into an electrical signal and transmit it to the phase measurement module 14, and the phase measurement module 14 compares the first photoelectric conversion unit D1 and the third photoelectric conversion unit D1 The phase difference variation of the output electrical signal of the second photoelectric conversion unit D2 obtains the displacement of the third corner cube prism 11, compares the phase difference variation of the output electrical signal of the first photoelectric conversion unit D1 and the third photoelectric conversion unit D3, and obtains the fourth The displacement of the corner cube 12, the displacement of the third corner cube 11 and the fourth corner cube 12 are averaged to obtain the displacement of the measured object; the displacement of the third corner cube 11 and the fourth corner cube 12 are subtracted to obtain Displacement difference, after dividing the displacement difference by the tip distance between the third corner cube prism 11 and the fourth corner cube prism 12, then calculate the arc sine to obtain the angle value of the measured object around the X axis; place the optical path behind the XY plane It can measure the angle value of the measured object around the Z axis.

Displacement measurement is optical eight subdivisions, and angle measurement is optical four subdivisions.

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

1. The present invention solves the problem of no displacement information on the basis of the existing dual-frequency laser interferometer goniometer by adding part A of the interference component. When measuring the multi-axis motion error of the guide rail of high-precision CNC machine tools, the angular error can be accurately positioned on the guide rail.

2. In the present invention, the second corner cube 7 and the second quarter-wave plate 9 are added to measure the optical multiple by improving part B of the multiplier component, and the displacement of a single corner cube is optical four subdivisions, Angle measurement is therefore optically quadratic. Displacement measurement is an optical eight subdivision, and the measurement resolution has been improved.

Description of drawings

FIG. 1 is a schematic diagram of the principle of an existing dual-frequency laser interferometer goniometer.

Fig. 2 is a schematic diagram of the principle and device of the dual-frequency laser displacement and angle interferometer of the present invention.

detailed description

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

For ease of description, the present invention uses spatially relative terms such as "upper", "lower", "left", and "right" to describe the relationship between one element and another element shown in the drawings. It should be understood that, Spatial terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" other elements would then be oriented "above" the other elements; thus, the exemplary term "below" could encompass both an orientation of above and below. The device may be otherwise oriented (rotated 900 or at other orientations) and the spatially relative specifications used herein interpreted accordingly.

As shown in Figure 2, a dual-frequency laser displacement and angle interferometer of the present invention includes a frequency-stabilized dual-frequency laser 1, a partially reflective beam splitter 2, an interference component A, an octave component B and a target arranged in sequence from left to right The mirror assembly C also includes a first photoelectric conversion unit D1, a second photoelectric conversion unit D2, a third photoelectric conversion unit D3, and a photoelectric conversion unit connected to the first photoelectric conversion unit D1, the second photoelectric conversion unit D2 and the third photoelectric conversion unit D3 Phase measurement module 14;

The output laser of the frequency-stabilized dual-frequency laser 1 is an orthogonally polarized frequency-stabilized _dual -frequency laser, and the output lights are f1 light whose polarization state is parallel to the YZ plane, that is, P _- polarized light and f2 whose polarization state is parallel to the XY plane. Light is S-polarized light;

The partially reflective beamsplitter 2 is composed of two right-angle prisms bonded along the slope, and a non-polarizing partially reflective beam-splitting film is coated on the slope of the right-angle prism;

The interference assembly A includes a first corner cube prism 3, a first quarter-wave plate 4, a non-polarizing beam-splitting prism 5 and a first polarizing beam-splitting prism 6 arranged in sequence from top to bottom, and the non-polarizing beam-splitting prism 5 and the first polarizing beam splitter prism 6 are all made up of two rectangular prisms bonded along the inclined plane, the upper surface of the first quarter wave plate 4 is bonded to the bottom surface of the first corner cube prism 3, and the lower surface is bonded to the bottom surface of the first corner cube prism 3. The upper right-angled surface of the non-polarizing beam-splitting prism 5, the lower right-angled surface of the non-polarizing beam-splitting prism 5 is bonded to the upper right-angled surface of the first polarizing beam-splitting prism 6; There is a non-polarized beam-splitting film, reaching a splitting ratio of 50:50, and a polarized beam-splitting film is coated on the slope of the rectangular prism of the first polarized beam-splitting prism 6;

The multiplier component B includes a second corner cube prism 7, a second polarization beam splitter prism 8 and a reflector 10 arranged in sequence from top to bottom, and the second polarization beam splitter prism 8 is composed of two right-angle prisms bonded along an inclined plane , the reflector 10 is a right-angle trapezoidal prism coated with a depolarized total reflection film on the slope, and its slope is parallel to the slope of the right-angle prism of the second polarization beam splitter prism 8, and the top of the second polarization beam splitter prism 8 The right-angled surface is bonded to the bottom surface of the second corner cube prism 7, and the lower right-angled surface is bonded to the upper right-angled surface of the reflector 10, and the inclined surface of the right-angled prism of the second polarization beam splitter prism 8 is coated with a polarization beam splitting film. Including the second quarter-wave plate 9 bonded to the right end surface of the second polarization beam splitter prism 8 and mirror 10;

The target mirror assembly C includes a corner cube holding base 13, and a third corner cube 11 and a fourth corner cube 12 bonded to the inside of the corner cube holding base 13;

Three corner cube surfaces of the first corner cube prism 3, the second corner cube prism 7, the third corner cube prism 11 and the fourth corner cube prism 12 are coated with a total reflection film;

The angle between the optical axis of the first quarter-wave plate 4 and the second quarter-wave plate 9 and the polarization direction of the f1 light emitted by the frequency-stabilized dual-frequency laser ₁ is 45°;

The non-polarized partially reflective spectroscopic film coated on the inclined surface of the partial reflective beam splitter 2 reaches a splitting ratio of 10:90.

The frequency-stabilized dual-frequency laser 1, the partially reflecting beam splitter 2, components A and B are fixed in position, and component C is installed on the object to be measured and moves with the object to be measured.

The working principle of the present invention is: the frequency-stabilized _dual -frequency laser ₁ emits orthogonally polarized lasers with frequencies f1 and f2, and a small part of the light is reflected to the first photoelectric conversion unit D1 after passing through the partial reflection beam splitter 2 and converted into electric After the signal is transmitted to the phase measurement module 14, the transmitted light is divided into two beams by the non-polarizing beam splitter 5, one beam is used for measurement, and the other beam is used as a reference. The measurement light is split by the multiplier component B and then vertically incident on the third corner cube prism 11 and the fourth corner cube prism 12, and then returns to combine with the reference light. The combined light of the measurement light and the reference light is split by the first polarizing beam splitter prism 6 and then incident to the second photoelectric conversion unit D2 and the third D3 photoelectric conversion unit to be converted into electrical signals and transmitted to the phase measurement module 14 . When the measured object moves along the Y direction together with the target mirror assembly C, the phase measurement module 14 simultaneously detects the first photoelectric conversion unit D1 and the second photoelectric conversion unit D2, and the first photoelectric conversion unit D1 and the third photoelectric conversion unit The displacement of the third corner cube prism 11 and the fourth corner cube prism 12 can be obtained from the phase difference variation of the output electrical signal of D3, and the displacement of the measured object can be measured by the average of the two. The difference between the displacement of the third corner cube prism 11 and the fourth corner cube prism 12 and the ratio of the distance between the corners of the third corner cube prism 11 and the fourth corner cube prism 12 is calculated to obtain the small angle value of the measured object around the X axis by calculating the arc sine. . After placing the optical path on the XY plane, the angle value of the measured object around the Z axis can be measured.

Claims (5)

1. A dual-frequency laser displacement and angle interferometer, characterized in that it includes a frequency-stabilized dual-frequency laser (1), a partially reflecting beam splitter (2), an interference component (A), and an octave The assembly (B) and the target mirror assembly (C) also include the first photoelectric conversion unit (D1), the second photoelectric conversion unit (D2), the third photoelectric conversion unit (D3) and the first photoelectric conversion unit (D1) , a phase measurement module (14) connected to the second photoelectric conversion unit (D2) and the third photoelectric conversion unit (D3); The output laser of the frequency-stabilized dual-frequency laser (1) is an orthogonally polarized frequency-stabilized dual-frequency laser, and the output lights are f ₁ light whose polarization state is parallel to the YZ plane, that is, P light, and f ₂ light whose polarization state is parallel to the XY plane. Light is S light; The partially reflective beam splitter (2) is composed of two right-angle prisms bonded along the slope, and the slope of the right-angle prism is coated with a non-polarizing partially reflective beam-splitting film; The interference component (A) includes a first corner cube prism (3), a first quarter-wave plate (4), a non-polarizing beamsplitter (5) and a first polarizing beamsplitter ( 6), the non-polarizing beam-splitting prism (5) and the first polarizing beam-splitting prism (6) are both composed of two right-angle prisms bonded along the slope, and the upper surface of the first quarter-wave plate (4) is bonded connected to the bottom surface of the first corner cube prism (3), the lower surface is glued to the upper right-angled surface of the non-polarizing beam-splitting prism (5), and the lower right-angled surface of the non-polarizing beam-splitting prism (5) is glued to the first polarizing The upper right-angled surface of the prism (6); the non-polarized beam-splitting film is coated on the oblique surface of the right-angled prism of the non-polarized beam-splitting prism (5) to achieve a splitting ratio of 50:50, and the first polarized beam-splitting prism (6 ) The oblique surface of the right-angle prism is coated with a polarizing beam-splitting film; The multiplier component (B) includes a second corner cube prism (7), a second polarization beamsplitter prism (8) and a reflector (10) arranged in sequence from top to bottom, and the second polarization beamsplitter prism (8) It is composed of two right-angle prisms bonded along the slope, the reflector (10) is a right-angle trapezoidal prism coated with a depolarizing total reflection film on the slope, and its slope is connected with the right-angle prism of the second polarization splitter prism (8) The slopes are parallel to each other, the upper right-angled surface of the second polarizing beam splitter (8) is bonded to the bottom surface of the second corner cube (7), and the lower right-angled surface is bonded to the upper right-angled surface of the reflector (10). The oblique surface of the rectangular prism of the second polarizing beam splitting prism (8) is coated with a polarizing beam splitting film, and also includes the second quarter of the right end face of the second polarizing beam splitting prism (8) and the reflector (10). A wave plate (9); The target lens assembly (C) includes a corner cube holding base (13), and a third corner cube (11) and a fourth corner cube (12) bonded to the inside of the corner cube holding base (13) ; The three corner cube surfaces of the first corner cube prism (3), the second corner cube prism (7), the third corner cube prism (11) and the fourth corner cube prism (12) are coated with a total reflection film; The included angle between the fast axis of the first quarter-wave plate (4) and the second quarter-wave plate (9) and the polarization direction of f1 light emitted by the frequency-stabilized dual-frequency laser ( ₁ ) is 45°; The positional relationship of the above components meets the following requirements: The f ₁ light emitted by the frequency-stabilized dual-frequency laser (1), that is, the P light, passes through the partial reflection beam splitter (2), and a part of the f ₁ light is reflected to the first photoelectric conversion unit (D1), and the transmitted light of the f1 light passes through the non- The polarizing beam splitter (5) is divided into two beams of light of equal light intensity, that is, the reflected light and the transmitted light; the reflected light passes through the first quarter-wave plate (4) in sequence, and is formed by the first corner cube prism (3), the first four One-half wave plate (4), non-polarizing beam splitting prism (5), first polarizing beam splitting prism (6) enters the third photoelectric conversion unit (D3); the transmitted light passes through the second polarizing beam splitting prism (8), the second polarizing beam splitting prism (8) and Two quarter-wave plates (9), consisting of a third corner cube (11), a second quarter-wave plate (9), a second polarizing beamsplitter (8), a second corner cube (7), The second polarizing beam splitter (8), the second quarter wave plate (9), the third corner cube (11), the second quarter wave plate (9), the second polarizing beam splitting prism (8) , the non-polarizing beam splitting prism (5), and the first polarizing beam splitting prism (6) enter the second photoelectric conversion unit (D2); The f2 light emitted by the frequency-stabilized dual-frequency laser (1), that is, the S light, passes through the partial reflection beam splitter (2), and a part of the f2 light is reflected to the first photoelectric conversion unit (D1), and the transmitted light of the f2 light passes through the non-polarized beam splitter The prism (5) is divided into two beams of light of equal light intensity, namely the reflected light and the transmitted light; the reflected light passes through the first quarter-wave plate (4) successively, and is formed by the first corner cube prism (3), the first quarter-wave plate A wave plate (4), non-polarizing beam-splitting prism (5), and the first polarizing beam-splitting prism (6) enter the second photoelectric conversion unit (D2); the transmitted light passes through the second polarizing beam-splitting prism (8) and the mirror ( 10), the second quarter-wave plate (9), composed of the fourth corner cube (12), the second quarter-wave plate (9), the mirror (10), the second polarizing beam splitter (8 ), the second corner cube (7), the second polarization beam splitter (8), the mirror (10), the second quarter wave plate (9), the fourth corner cube (12), the second Quarter-wave plate (9), mirror (10), second polarizing beamsplitter prism (8), non-polarizing beam splitting prism (5), first polarizing beam splitting prism (6) and then enters the third photoelectric conversion unit (D3 ). 2. A dual-frequency laser displacement and angle interferometer according to claim 1, characterized in that: the non-polarized partially reflective spectroscopic film coated on the slope of the partially reflective beam splitter (2) achieves a 10:90 split Compare. 3. A dual-frequency laser displacement and angle interferometer according to claim 1, characterized in that: the frequency-stabilized dual-frequency laser (1), partially reflective beam splitter (2), interference component (A) and multiplier The position of the process component (B) is fixed, and the target mirror component (C) is installed on the measured object and moves with the measured object. 4. A dual-frequency laser displacement and angle interferometer according to claim 3, characterized in that: the first photoelectric conversion unit (D1), the second photoelectric conversion unit (D2) and the third photoelectric conversion unit ( D3) Convert the optical signal into an electrical signal and transmit it to the phase measurement module (14), and the phase measurement module (14) compares the phase difference change of the output electrical signal of the first photoelectric conversion unit (D1) and the second photoelectric conversion unit (D2) amount to obtain the displacement of the third corner cube (11), compare the phase difference variation of the output electrical signals of the first photoelectric conversion unit (D1) and the third photoelectric conversion unit (D3), and obtain the fourth corner cube (12) The displacement of the third corner cube (11) and the fourth corner cube (12) are averaged to obtain the displacement of the measured object; the displacement of the third corner cube (11) and the fourth corner cube (12) Subtract the displacement difference, divide the displacement difference by the distance between the third corner cube prism (11) and the fourth corner cube prism (12), and calculate the arc sine to get the angle value of the measured object around the X axis ; After placing the optical path on the XY plane, the angle value of the measured object around the Z axis can be measured. 5. A dual-frequency laser displacement and angle interferometer according to claim 4, characterized in that: the displacement measurement is optical eight subdivisions, and the angle measurement is optical four subdivisions.