TW201723418A - An optical system and measuring methods for simultaneous absolute positioning distance and tilting angular measurements of a moving object - Google Patents

Abstract

An optical measuring system comprises a focus lens generating a focused beam, a birefringent beam splitter (BBS), and a beam splitter. The BBS divides the focused beam into a first and a second polarizing beams having polarization to be orthogonal each other. The beam splitter divides the first and second polarizing beams, respectively, into a first part of beams projecting onto an object underlying absolute distance and tilting angular (yaw/pitch) measurement and reflecting thereby to form a first and a second reflecting lights, and the other part of beams reflecting from the beam splitter thereby forming a first and a second reference lights, respectively. The first and second reflecting lights respectively interfere with the first and second references light thereby forming a first and a second interference lights and then be combined to form a combined light without any interference by the BBS. The optical detector can be further adapted in an optical interferometer for detecting positioning absolute distance and titling angle, and measurements of the moving object. Alternatively, a multi-wavelength measurement can be adapted for increasing the measurable detection range.

Description

Optical system and method for simultaneous measurement of absolute positioning distance and yaw angle of moving objects

The invention relates to an optical system and a method, in particular to an optical system and a measuring method capable of simultaneously detecting an absolute positioning distance and a yaw angle.

With the market demand, optical components and electronic components booming, it is not difficult to build a system with nano-level resolution. The measuring instruments commonly seen on the market include white light interferometers, Fizeau interferometers and McKesson interferometers, and with phase shifting and phase analysis techniques, the resolution can be measured to submicron or nano absolute distance. Level.

In these precision measurement systems, if the conditions such as the vibration generated by the environment or the machine's own mechanism, the correction of the machine's reference position, or the correction of the position of the object to be tested are not well adjusted and controlled, it may be The measurement results in a large error. Among these conditions, which affect the measurement results, the position of the machine and the correction of the placement of the object to be tested are indispensable elements in precision measurement.

Therefore, in the conventional technology, for example, the Patent No. I452262 of the Republic of China, discloses an interferometer system for simultaneously measuring displacement and inclination, which comprises a light source group, an interferometer group, a sight gauge and a a signal processing module, the light source group is provided with a transmitter that emits a non-polarized beam, the interferometer group is provided with a polarization beam splitter, a corner 隅稜鏡, a two-dimensional position sensitive sensor, a mirror plate, and two wavelength delays. And a polarizing plate, the collimator receives the measuring beam generated by the interferometer group as a light source and is provided with a plating film, a two-dimensional position sensitive sensor and a focusing lens, and the signal processing module receives two ones The signal of the position sensitive sensor and the signal of the two-dimensional position sensitive sensor are respectively processed by a signal processor to obtain the displacement and inclination of the corner.

Furthermore, as Shyh-Tsong Lin et al., Disclosed the phase shift angle scanning Savart shearing interferometer paper, (Angular scanning white light shearing interferometer , 15 th International Conference on Experimental Mechanics, 22-27 / July, 2012 A technique for measuring the slope profile of an object is disclosed. In this technique, as shown in FIG. 1, the Savart 稜鏡 11 on the turntable 10 is used as a shearing mechanism, and the optical path difference formed by the two shear wavefronts is utilized, and the object to be tested 12 and the Savart edge are simultaneously used. The phase angle of the angle formed by the mirror 11 is shifted. In the present technique, by rotating the Savart 稜鏡 11 angle Δα, the analyzer 13 penetrates the axis in the X-axis direction. After the light passes through the polarizing plate 14 and the beam splitter 15 along the Z axis, the light becomes linearly polarized, and the light is sheared into two rays eo and oe through the Savart稜鏡11, and the cutting distance is S. After the light is reflected back from the object to be tested 12, the two lights are merged again by Savart稜鏡11, guided to the analyzer 13 by the beam splitter 15, and interference is generated and sensed by the photo sensor 16.

In the conventional technology, an internal measuring instrument using an optical scale or a ceramic piezoelectric element on a motor is also used for measurement, but the accuracy and function thereof cannot be flexibly modified by the user. In addition, the method of the conventional technology can not immediately know the tilt angle of the object to be tested, which needs to be scanned and a large number of operations to be known, thereby affecting the efficiency of the measurement.

The present invention provides an optical system that utilizes the characteristics of a birefringent element to form two mutually orthogonal optical paths, and that partially reflects and forms a reference light and partially penetrates and forms the object light as the two optical paths exit the system. When the object light is reflected back to the system by the object to be tested, due to the interference of the optical path difference between the object light and the reference light, the interference information can quickly measure the absolute distance between the two positions on the object, Surface topography and skewed poses such as roll, pitch and yaw. In addition, based on the distance and tilt information, it can be used to adjust the posture of the object in space and reduce the error caused by the tilt. Since the absolute distance and tilt measurement have the advantages of positioning and Abbe error correction, the optical system of the present invention can be applied to the correction of various machine tools, and the accuracy of the machine tool is improved.

The invention provides an optical interference system, through which an optical system with a focusing lens and a Savart(R) is arranged, so that the beam forms two parallel rays whose polarization is orthogonal to each other, and finally the reflection and penetration phenomenon are simultaneously generated by the special coated beam splitter. The penetrating light is reflected back to the measuring system and then reflected back to the measuring system, so that the light reflected back at the outlet of the measuring system interferes with the light reflected back from the object to be tested. Then, by detecting the light intensity of the individual single wavelengths by using the signal and deducing the phase values of the individual wavelengths, the phase values of the equivalent wavelengths can be reconstructed by using the two information to obtain the optical path difference of the equivalent wavelength, and This serves as the absolute distance between the optical system and the object to be tested. Through the system of the present invention, a multi-point measurement can be formed to measure the tilt state of the object.

In one embodiment, the present invention provides an optical system including a focusing lens, a birefringent beam splitting element, and a beam splitting element. The focusing lens is used to focus a light beam. The birefringence beam splitting element is configured to split the focused beam to form first and second polarized lights whose polarization states are orthogonal to each other. The light splitting element is configured to split the first and second polarized lights, so that part of the first and second polarized lights are reflected by the light splitting element to form a first reference light and a second reference light, and part of the first and the first The second polarized light penetrates the light splitting element and is projected onto an object to reflect and form a first object light and a second object light, and the first object light and the second object light enter the light splitting element and respectively respectively with the first reference The light and the second reference light interfere to form a first interference light and a second interference light, and the first and second interference light are combined by the birefringence beam splitting element to form a combined light beam that does not interfere with each other.

In another embodiment, the present invention provides an optical interference system comprising: a light source, a light guiding element, and an optical system. The light guiding element is coupled to the light source for guiding the light beam generated by the light source. The optical system is coupled to the light guiding element, and the optical system further has a focusing lens, a birefringent beam splitting element, and a beam splitting element. The focusing lens is used to focus the beam. The birefringence beam splitting element is configured to split the focused beam to form first and second polarized lights whose polarization states are orthogonal to each other. The light splitting element is configured to split the first and second polarized lights, so that part of the first and second polarized lights are reflected by the light splitting element to form a first reference light and a second reference light, and part of the first and the first The second polarized light penetrates the light splitting element and is projected onto an object to reflect and form a first object light and a second object light, and the first object light and the second object light enter the light splitting element and respectively respectively with the first reference The light and the second reference light interfere to form a first interference light and a second interference light, and the first and second interference light are combined by the birefringence beam splitting element to form a combined light beam that does not interfere with each other.

In still another embodiment, the present invention provides an optical interference system including: a light source, a polarization unit, a coupler, a light guide module, and an optical system. The light source is configured to provide a plurality of beams each having a wavelength. The polarization unit is configured to polarize the plurality of beams. The coupler is configured to combine the plurality of polarized beams into a detection beam. The light guiding module is coupled to the coupling to guide the detecting beam. The optical system is coupled to the light guiding module for receiving the detecting beam. The optical system further has a focusing lens, a birefringent beam splitting component and a beam splitting component. The focusing lens is used to focus the detecting beam. The birefringence beam splitting element is configured to split the focused detecting beam to form first and second polarized lights whose polarization states are orthogonal to each other. The light splitting element is configured to split the first and second polarized lights, so that part of the first and second polarized lights are reflected by the light splitting element to form a first reference light and a second reference light, and part of the first and the first The second polarized light penetrates the light splitting element and is projected onto an object to reflect and form a first object light and a second object light, and the first object light and the second object light enter the light splitting element and respectively respectively with the first reference The light and the second reference light interfere to form a first interference light and a second interference light, and the first and second interference light are combined by the birefringence beam splitting element to form a combined light beam that does not interfere with each other. The optical system further includes a first beam splitting module, a second beam splitting module, a light sensing module and an arithmetic processing device. The first beam splitting module is configured to split the combined light beam into split beam beams corresponding to different wavelengths. The second beam splitting module is configured to split the split light beams of different wavelengths into first interference light and second interference light corresponding to different polarization states. The light sensing module is configured to sense first and second interference lights of different wavelengths to generate corresponding interference light intensity information. The arithmetic processing device determines a position depth and a lateral separation distance of the first and second interference lights on the object according to the interference light intensity information, thereby determining a tilt angle of the object.

In one embodiment, the present invention provides an optical method for simultaneous measurement of absolute positioning distance and yaw angle, comprising the steps of first providing a focused beam, and then splitting the focused beam with a birefringent beam splitting element. And forming first and second polarized lights whose polarization states are orthogonal to each other. Then, a splitting element is further used to split the first and second polarized lights, so that part of the first and second polarized lights are reflected by the splitting element to form a first reference light and a second reference light, and a part of the first The second polarized light is projected through the light splitting element onto an object, and the reflection forms a first object light and a second object light, and the first object light reflected by the object and the second object light pass through the light splitting element respectively Interfering with the first reference light and the second reference light to form a first interference light and a second interference light. Next, the first and second interference lights are combined by the birefringence beam splitting element to form a combined light beam that does not interfere with each other. Then, the interference light intensity information of the first and second interference lights in the combined light beam is sensed. Finally, the positional depth and the lateral distance of the first and second interference lights on the object are determined according to the interference light intensity information, thereby determining an inclination of the object.

In another embodiment, the light source can be a multi-wavelength light source. The multi-wavelength light source further includes the steps of generating a plurality of light beams with a light source, each light beam having a wavelength. The plurality of beams are then polarized. The plurality of polarized beams are then combined into a detection beam. Finally, a focusing lens is used to focus the detection beam to form the focused beam. The analyzing the multi-wavelength interference beam further includes the following steps: dividing the combined beam into the beam splitting beams corresponding to different wavelengths by using a first beam splitting module. Then, a second beam splitting module is used to split the split light beams of different wavelengths into first interference light and second interference light corresponding to different polarization states. In the next step, the light sensing module is used to sense the first and second interference lights of different wavelengths to generate corresponding interference light intensity information. Finally, an operation processing device is used, and the position depth and the lateral distance of the first and second interference lights on the object are determined according to the interference light intensity information, thereby determining a tilt angle of the object.

Please refer to FIG. 2A, which is a schematic diagram of an embodiment of an optical system of the present invention. The optical system 2 includes a focusing lens 20, a birefringent beam splitting element 21, and a beam splitting element 22. The focusing lens 20 is disposed inside the optical system 2 for focusing a light beam 90. In one embodiment, the beam 90 is emitted via a source of light and is directed through the fiber 300 to the focusing lens 20 via the polarizing element. In an embodiment, the light source is an infrared light source, but is not limited thereto. The birefringence beam splitting element 21 is disposed inside the optical system 2 and located on one side of the focusing lens 20 for splitting the focused beam to form a first polarized light 91a whose polarization states are orthogonal to each other and the optical paths are parallel to each other. And a second polarized light 91b. The birefringent beam splitting element 21 is composed of a birefringent material. In the present embodiment, the birefringent beam splitting element 21 may be Savart稜鏡, but is not limited thereto, such as Wollaston稜鏡, Nomarski稜鏡, and grating. And other components. As shown in FIG. 2B, after the incident light 90 is polarized, the polarization state Ein is 45 degrees, as shown in FIG. 2B(a), and the Savart稜鏡21 is divided into two polarized lights that are perpendicular to each other. They are eo-polarized light 91a and oe-polarized light 91b, respectively, as shown in Fig. 2B(b). The two lights will advance in a parallel state in space and maintain their polar state, and the light intensity is 50% of the original incident light.

Returning to FIG. 2A, the beam splitting element 22 is disposed at an end of the optical system 2 such that the eo-polarized light 91a and the oe-polarized light 91b are separated from the end portion, and the first The second polarized lights 91a and 91b are split, so that the first and second polarized lights 91a and 91b are reflected by the light splitting element 22 to form a first reference light 92a and a second reference light 92b, and the first and second portions are made. The polarized lights 91a and 91b are projected through the beam splitting element 22 to the object 8, and are further reflected to form a first object light 93a and a second object light 93b. It is to be noted that the beam splitting element 22 may be integrated with the optical system 2 or be two separate components. In an embodiment, the object may be a grating, a sample to be tested, or an external reference plane or the like. The first object light 93a and the second object light 93b reflected by the surface of the object 8 again enter the beam splitting element 22 and interfere with the first reference light 92a and the second reference light 92b to form a first interference light and A second interference light, the first and second interference lights return to the birefringent beam splitting element 21 along the original optical path, and are combined again to form a combined light beam. Since the polarization states of the first interference light and the second interference light are orthogonal to each other, the two light beams do not interfere with each other after the light combination. It should be noted that, taking the birefringence beam splitting element 21 as Savart稜鏡 as an example, when the two first object light 93a and the second object light 93b pass through Savart稜鏡 again, the result is restored to the original incident bias again. Polar state, for example: 45 degree partial polar state. However, it should be noted that during the process of travel, the two mutually opposite polar lights cannot change in a polar state. Otherwise, they will be separated into two mutually perpendicular polar lights when incident Savart稜鏡. . By using this principle, the two lights can be separated and measured in parallel in the horizontal space, and even the reversibility after reflection can be used to recombine the two lights into a polarized light of 45 degrees. And the oe-polar and eo-polar states do not interfere with each other, retaining the original information. In addition, since the two lights simultaneously acquire the lateral space distance of the surface of the object at one time, even if the object is in the same direction of vibration or motion as the optical path, the lateral space distance of the surface of the object can be obtained without being affected, thereby obtaining the positioning. Distance and yaw angle information.

As shown in FIG. 3, the figure is a schematic diagram of an optical interference system structure formed by the optical system of FIG. 2A. In this embodiment, the light beam generated by the light source module 30a in the system 3 is polarized by the polarization unit 31a, and the light beam formed by the light source module 30a passes through the light guide module 33a. In this embodiment, the circulator is turned into a circulator. The optical system 2 generates two first and second polarized beams of a distance Δs projected onto the object 8a. After being reflected from the object 8a, after being interfered with the reference beam in the optical system 2, the combined light beam is again combined to form a combined light beam. After the light beam exits the optical system 2, it is transmitted to the light guiding module 33a via the optical fiber, and is guided to a polarization beam splitter (PBS) 35a for separating the combined light beam into the first interference light and Second interference light. After the splitting, the first and second interference lights are respectively detected by the photo sensors 36a and 36b, such as a photodetector, a CCD or a CMOS sensor, and the respective light intensities are detected, and the individual wavelengths can be calculated by the arithmetic processing device 37a. The phase value is then used to solve the phase under a specific optical path difference after a single wavelength interference, and is further used to reverse the optical path difference to obtain the distances d1 and d2 of the object detection position. In one embodiment, the manner in which the optical path difference is generated can be achieved by moving the spectroscope (element 22 of FIG. 2A) through the moving optical system 2, or by separately moving the spectroscope. Phase shifting can be performed using a three-step phase shift, a four-step phase shift, a five-step phase shift, or a (N+1) step phase shift. Finally, the angle of inclination of the object 8a can be known from the distance Δs of the two lights and the distances d1 and d2.

In order to increase the measurement step height or limit the depth range of the object, multi-wavelength interference can be used, and two wavelengths close to the wavelength can be used to achieve equivalent wavelengths close to the centimeter level, such as 1569.18 nm and 1546.68 nm. Wavelength interference can produce an equivalent wavelength of 545.61 microns, but it is not limited by this and can be determined according to requirements. In an embodiment, as shown in FIG. 4, it is a schematic diagram of an embodiment of an optical interference system architecture of the present invention. In this embodiment, the optical interference system 3 includes a light source module 30, a polarization unit 31, a coupler 32, a light guide module 33, and an optical system 2. The light source module 30 in this embodiment is a module composed of dual light sources 301 and 302. Each of the light sources 301 and 302 is an infrared light source, and respectively provides different wavelengths, but two wavelengths are relatively close to infrared rays. The multi-wavelength interferometry used in the present invention can be applied to measure a standard step height block having a large step difference to expand the range of measurement. Taking dual wavelength as an example, the application method is first for two wavelengths. versus Perform phase shifting individually and find the unknown phase versus , get unknown phase versus After subtracting the two phase information, the phase information of the equivalent wavelength can be obtained. , the formula is as in formula (1). ………..…..(1)

among them Is the equivalent wavelength, versus Two different wavelengths versus Phase information, It is the phase information of the equivalent wavelength. and The formula is as shown in the following formula (2). …………….(2)

As shown in Figure 5, the principle of multi-wavelength application, taking two wavelengths as an example, is at two different wavelengths. versus Take a common multiple relationship between individual wavelengths versus The period between the two is different, and the phase relationship between the two needs to go through the cycle of the common multiple to repeat the same phase relationship, so the principle can be used to generate the equivalent wavelength. , thereby expanding the range of distance measured.

Different wavelengths produced by light sources 301 and 302 versus The infrared ray beam forms a polarized beam via the polarization unit 31. In this embodiment, the polarization unit 31 further has a first polarization element 310 and a second polarization element 311 coupled to the light sources 301 and 302, respectively. In this embodiment, the two polarized beams are formed to have a polarization angle of 45 degrees, but are not limited thereto. The two polarized beams are directed to the coupler 32 via the optical fiber 300. The two polarized beams are combined via a coupler 32 into a detected beam that can be transmitted within the fiber 300. In an embodiment, the coupler 32 can use a Dense Wavelength Division Multiplexing (DWDM). The coupling 32 is coupled to the light guiding module 33 , and the light guiding module 33 receives the combined light beam from the coupling 32 . In this embodiment, the light guiding module 33 includes an optical fiber 300 and a circulator 33, one of the optical fibers 300 is connected to the coupling 32 and the circulator 33, and the other optical fiber 300 is connected to the circulator 33 and the optical system. 2. The circulator 33 is provided to allow the detection beam to pass through to the optical system 2.

The structure of the optical system 2 is as shown in FIG. 2A. The detection beam entering the optical system 2 forms two first polarized lights (eo waves) and a second polarized light which are mutually orthogonal to each other. (oe wave), and spaced apart by Δs, onto the object 8a. The object 8a described in this embodiment is a grating, but is not limited thereto. The first object light is reflected by the object 8a and the second object light retains the polarization states of the first and second polarized lights, respectively, and after entering the optical system 2, respectively, is reflected by the beam splitting element of the optical system 2 The first reference light and the second reference light interfere with each other to form first and second interference lights. The first and second interference lights are again combined by Savart(R) in the optical system 2 to form a combined light beam that does not interfere with each other.

The combined light beam is guided to the first beam splitting module 34 through the circulator 330 for splitting the combined light beam into first and second split light beams corresponding to different wavelengths. In this embodiment, the first beam splitting module 34 is a DWDM, such that the first splitting beam is the wavelength of the corresponding source 301. Spectroscopic beam containing the corresponding wavelength First interference light and second interference light; likewise, the second split light beam is corresponding to the wavelength of the light source 302 Spectroscopic beam containing corresponding wavelengths The first interference light and the second interference light.

Subsequently, the first beam splitting beam is guided via the optical fiber to the second beam splitting module 35, which has a beam splitting element 351 and a beam splitting element 352. The splitting element 351 is coupled to the first beam splitting module 34 via the optical fiber 300, and the splitting element 351 is configured to split the first combined light beam into mutually opposite polar states and corresponding wavelengths. First interference beam Second interference beam The splitting element 352 is coupled to the first beam splitting module 34 via the optical fiber 300, and the beam splitting element 352 is configured to divide the second interference beam into mutually orthogonal states and corresponding wavelengths. First interference beam Second interference beam . The second beam splitting module 35 is further coupled to the light sensing module 36. The light sensing module 36 has a plurality of light sensing units 360-363 for sensing corresponding wavelengths. versus The first and second interference beams, in turn, generate corresponding interference light intensity information. In an embodiment, the light sensing unit is a photodetector, a CCD, or a CMOS sensing element.

The optical sensing module 36 is electrically connected to an arithmetic processing device 37. The arithmetic processing device 37 has an arithmetic processing capability and can be a workstation or a computer device, but is not limited thereto. The arithmetic processing device 37 has a basic algorithm for solving the phase, for example, a three-step phase shift, a four-step phase shift, a five-step phase shift, and a (N+1) step phase shift for parsing the first interference based on the interference light intensity information. beam versus First interference beam versus The object heights are d1 and d2. Since the distance Δs between the first and second polarized beams formed by the Savart lens is known, the tilt state of the object can be known from the object heights d1 and d2 and the distance Δs.

In summary, the optical system and method for measuring the absolute positioning distance and the yaw angle of the moving object of the present invention can be used to measure the absolute distance and surface of the two positions on the object simultaneously and quickly by using a single point measurement method. The shape and the skewed posture have the advantages of positioning and Abbe error correction, and can be applied to the correction of various machine tools, and the accuracy of the machine tool is improved. The measurement system with high precision and Abbe error correction can increase the type of measuring object of the machine tool, and can even be used as a wafer exposure machine to enhance the added value of the industry.

The above description is only intended to describe the preferred embodiments or embodiments of the present invention, which are not intended to limit the scope of the invention. That is, the equivalent changes and modifications made in accordance with the scope of the patent application of the present invention or the scope of the invention are covered by the scope of the invention.

10‧‧‧ turntable
11‧‧‧ Savart稜鏡
12‧‧‧Test object
13‧‧‧Check plate
14‧‧‧ deflecting plate
15‧‧‧beam splitter
16‧‧‧Light sensor
2‧‧‧Optical system
20‧‧‧focus lens
21‧‧‧Birefringence beam splitting element
22‧‧‧Spectral components
300‧‧‧ fiber
3. 3a‧‧‧Optical Interference System
30, 30a‧‧‧ Optical Module
301, 302‧‧‧ light source
31, 31a‧‧ ‧Polarization unit
310‧‧‧First Polarization Element
311‧‧‧second polarization element
32‧‧‧ coupling
33, 33a‧‧‧Light guide module
330‧‧‧Circulator
90‧‧‧ Beam
91a‧‧‧First Polar Light
34‧‧‧First beam splitting module
35‧‧‧Second splitting module
351‧‧‧ Spectroscopic components
352‧‧‧Spectral components
36‧‧‧Light sensing module
36a, 36b‧‧‧Photosensor
360~363‧‧‧Light sensing unit
37, 37a‧‧‧ arithmetic processing device
91b‧‧‧Second Polar Light
92a‧‧‧First reference light
92b‧‧‧second reference light
93a‧‧‧First light
93b‧‧‧Second light
8, 8a‧‧‧ objects

1 is a schematic diagram of a surface curvature optical detection architecture of the prior art; FIG. 2A is a schematic diagram of an embodiment of an optical system according to the present invention; FIG. 2B is a schematic diagram of first and second polarization beams orthogonal to each other; FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 4 is a schematic diagram of another embodiment of an optical interference system architecture according to the present invention; and FIG. 5 is a schematic diagram of equivalent wavelengths formed by dual wavelengths.

2‧‧‧Optical system

20‧‧‧focus lens

21‧‧‧Birefringence beam splitting element

22‧‧‧Spectral components

300‧‧‧ fiber

90‧‧‧ Beam

91a‧‧‧First Polar Light

91b‧‧‧Second Polar Light

92a‧‧‧First reference light

92b‧‧‧second reference light

93a‧‧‧First light

93b‧‧‧Second light

8‧‧‧ objects

Claims (21)

An optical system comprising: a focusing lens for focusing a beam; a birefringent beam splitting element for splitting the focused beam to form first and second polarized lights that are mutually orthogonal to each other; and The light splitting component is configured to split the first and second polarized lights, so that part of the first and second polarized lights are reflected by the light splitting component to form a first reference light and a second reference light, and part of the first and second The polarized light penetrates the light splitting element and is projected onto an object, and the reflection forms a first object light and a second object light, and the first object light and the second object light enter the light splitting element and respectively respectively with the first reference The light and the second reference light interfere to form a first interference light and a second interference light, and the first and second interference light are combined by the birefringence beam splitting element to form a combined light beam that does not interfere with each other. The optical system of claim 1, wherein the optical splitting element is a birefringent crystalline material. The optical system of claim 1, wherein the light beam is infrared light or a light beam having multiple wavelengths. An optical interference system includes: a light source module for generating a detection beam; a light guiding element coupled to the light source module for guiding the detection beam; an optical system, and the guide The optical component is coupled, the optical system further includes: a focusing lens for focusing the detecting beam; and a birefringent beam splitting component for splitting the focused beam to form a first and a second orthogonal to each other a second polarized light; and a light splitting element for splitting the first and second polarized light, wherein the first and second polarized lights are reflected by the light splitting element to form a first reference light and a second reference light, and Part of the first and second polarized lights are projected through the light splitting element onto an object to reflect a first object light and a second object light, and the first object light and the second object light enter the light splitting element respectively Interfering with the first reference light and the second reference light to form a first interference light and a second interference light, wherein the first and second interference lights are combined by the birefringence beam splitting element to form a non-interference one Combined light beam. The optical interference system of claim 4, wherein the beam splitting element is a birefringent crystal material. The optical interference system of claim 4, wherein the light guiding element is an optical fiber. The optical interference system of claim 4, further comprising: a light sensor for receiving the first and second interference lights to generate corresponding interference light intensity information; and an operation The processing device determines, according to the interference light intensity information, a position depth and a lateral distance of the first and second interference lights on the object, and further determines a tilt angle of the object. The optical interference system of claim 4, wherein the light source module is an infrared light source module or a light source module having a multi-wavelength beam. The optical interference system of claim 4, wherein the light source module further comprises: a light source for providing a plurality of light beams, each of the light beams having a wavelength; and a polarization unit for the plurality of light sources The beam is polarized; a coupler is configured to combine the plurality of polarized beams into a detection beam; and a light guiding module is coupled to the coupling to guide the detecting beam. The optical interference system of claim 9, wherein the light guiding module further comprises: a first optical fiber coupled to the coupling; a circulator coupled to the first optical fiber; A second optical fiber is coupled to the circulator and the optical system. The optical interference system of claim 10, further comprising: a first beam splitting module for splitting the combined beam into beams of light having different wavelengths; and a second beam splitting module Separating the splitting beams of different wavelengths into first interference light and second interference light corresponding to different polarization states; a light sensing module for sensing first and second interference lights of different wavelengths to generate phases Corresponding interference light intensity information; and an arithmetic processing device determining, according to the interference light intensity information, a position depth and a lateral distance of the first and second interference lights corresponding to the object, thereby determining an inclination of the object. The optical interference system of claim 11, wherein the first beam splitting module is a high density wavelength wavelength division multiplexer. The optical interference system of claim 11, wherein the second beam splitting module has a plurality of polarization plate splitters. The optical interference system of claim 9, wherein the coupler is a high density wavelength wavelength division multiplexer. An optical method for measuring the absolute positioning distance and the yaw angle synchronously, comprising the steps of: providing a focused beam; splitting the focused beam by a birefringent beam splitting element to form a first phase of mutually orthogonal polar states; a second polarized light; using a light splitting element to split the first and second polarized light, so that a portion of the first and second polarized light are reflected by the light splitting element to form a first reference light and a second reference light, and a portion The first and second polarized light are projected through the light splitting element onto an object, and the reflection forms a first object light and a second object light, and the first object light reflected by the object and the second object light pass through the light splitting Interacting with the first reference light and the second reference light respectively to form a first interference light and a second interference light; and causing the first and second interference light to be combined by the birefringence beam splitting element to form A combined light beam that does not interfere with each other. The optical method of claim 15, further comprising the steps of: sensing interference light intensity information of the first and second interference lights in the combined light beam; determining the light intensity information according to the interference light intensity information The position of the first and the second interference light is separated by a distance between the object and the lateral direction, thereby determining an inclination of the object. The optical method of claim 16, wherein providing the focused beam further comprises the steps of: generating a plurality of beams with a light source, each beam having a wavelength; polarizing the plurality of beams; A plurality of polarized beams combine to form a detection beam; and a focusing lens is used to focus the detection beam to form the focused beam. The optical method of claim 17, further comprising the steps of: dividing the combined beam into a split beam corresponding to different wavelengths by using a first beam splitting module; using a second beam splitting module to be different The splitting beam of the wavelength is divided into the first interference light and the second interference light corresponding to different polarization states; a light sensing module is configured to sense the first and second interference lights of different wavelengths to generate corresponding interference And an operation processing device, determining, according to the interference light intensity information, a position depth and a lateral distance of the first and second interference lights on the object, thereby determining an inclination of the object. The optical method of claim 18, wherein the first beam splitting module is a high density wavelength wavelength division multiplexer. The optical method of claim 18, wherein the second beam splitting module has a plurality of polarized beam splitters. The optical method of claim 17, wherein the light source further comprises a coupler, which is a high-density wavelength-wavelength multiplexer.