CN-122015661-A - Single-mirror double-shaft displacement measurement method and device applied to scanning interference field

CN122015661ACN 122015661 ACN122015661 ACN 122015661ACN-122015661-A

Abstract

The application provides a single-mirror double-shaft displacement measurement method and device applied to a scanning interference field, wherein the single-mirror double-shaft displacement measurement method and device comprises the steps of outputting difference frequency laser with vertical and orthogonal polarization, wherein the difference frequency laser comprises first polarized laser with first frequency and second polarized laser with second frequency, the first polarized laser is horizontally polarized, the second polarized laser is vertically polarized, the first polarized laser is reflected by a first plane mirror and then used as reference light to be injected into a first photoelectric detector, the second polarized laser is reflected by a second plane mirror and a third plane mirror and then used as measurement light to be injected into a second photoelectric detector, the offset angle of the first plane mirror is zero, and the offset angle of the second plane mirror is zero The offset angle of the third plane mirror is 2 And calculating the displacement of the object to be measured in the two-dimensional plane based on the interference of the measuring light and the reference light. The application can realize displacement measurement of two degrees of freedom in the plane by only using a single measuring reflector in cooperation with a single-axis laser interferometer.

Inventors

Ba Yinhexige
CUI YUHANG
LI WENHAO
LIU ZHAOWU
JIANG SHAN
WANG WEI
LI YUBO
JIANG YANXIU
WANG XINYU
ZHOU WENYUAN

Assignees

中国科学院长春光学精密机械与物理研究所

Dates

Publication Date: 20260512
Application Date: 20260414

Claims (10)

1. A single mirror biaxial displacement measurement method applied to a scanning interference field, comprising: Outputting a difference frequency laser with vertical orthogonal polarization, wherein the difference frequency laser comprises a first polarized laser with a first frequency and a second polarized laser with a second frequency, the first polarized laser is horizontally polarized, and the second polarized laser is vertically polarized; the first polarized laser is reflected by a first plane reflector and then is used as reference light to be injected into a first photoelectric detector, the second polarized laser is reflected by a second plane reflector and a third plane reflector and then is used as measurement light to be injected into a second photoelectric detector, wherein the offset angle of the first plane reflector is zero, and the offset angle of the second plane reflector is zero Is not zero, the offset angle of the third plane mirror is 2 ; Calculating the displacement of the object to be measured in the X direction of the two-dimensional plane based on the interference of the measuring light and the reference light And the displacement amount in the Y direction , wherein, Lambda R is the center wavelength of the difference frequency laser, A phase change is generated for the X-direction movement, A phase change is generated for the Y-direction movement, Is the offset angle of the second planar mirror.
2. The single mirror dual axis displacement measurement method of claim 1 wherein the offset angle of the second planar mirror 0.05 DEG to 1 deg.
3. The single mirror biaxial displacement measurement method of claim 1, wherein the first polarized laser light is reflected by the first plane mirror and then injected into the first photodetector as reference light, comprising: the first polarized laser is reflected by the first beam splitter prism, the polarized beam splitter prism and the first plane reflector in sequence and then is emitted into the first photoelectric detector through the polarized beam splitter prism and the first beam splitter prism again.
4. The single mirror biaxial displacement measurement method of claim 3, wherein the second polarized laser light is reflected by the second plane mirror and the third plane mirror and then is injected into the second photodetector as measurement light, and the method comprises: the second polarized laser is reflected by the first beam splitter prism, the polarized beam splitter prism, the quarter wave plate and the second plane reflector in sequence, then passes through the quarter wave plate again, changes the polarization state into horizontal polarization, passes through the polarized beam splitter prism again, is reflected by the third plane reflector, returns in the original path, and is injected into the second photoelectric detector through the first beam splitter prism.
5. The method of measuring single-mirror biaxial displacement according to claim 4, wherein the distance between the second plane mirror and the polarization beam splitter prism is larger than the distances between the first plane mirror, the third plane mirror and the polarization beam splitter prism.
6. The single mirror biaxial displacement measurement method according to claim 4, further comprising: And rigidly connecting the second plane reflector with the two-dimensional plane of the object to be measured, so that the displacement of the object to be measured in the X direction and the Y direction of the two-dimensional plane is measured by measuring the displacement of the second plane reflector in the X direction and the Y direction of the two-dimensional plane.
7. A single mirror biaxial displacement measurement method according to claim 3, further comprising: The first polarized laser and the second polarized laser enter the first photoelectric detector through the first beam splitting prism to form a reference interference signal.
8. The single mirror biaxial displacement measurement method of claim 1, wherein the output of the difference frequency laser of orthogonal polarization is a dual frequency laser or two independent single frequency lasers.
9. The method for measuring displacement of single mirror and double shaft according to claim 8, wherein when the difference frequency laser outputting the vertical orthogonal polarization is two independent single frequency lasers, the method further comprises a second beam combining prism, and the reference light and the measuring light are injected into the second photoelectric detector through the second beam combining prism.
10. A single mirror biaxial displacement measurement device for scanning an interference field, comprising: the laser outputs difference frequency laser with vertical orthogonal polarization, wherein the difference frequency laser comprises first polarized laser with first frequency and second polarized laser with second frequency, the first polarized laser is horizontally polarized, and the second polarized laser is vertically polarized; The first photoelectric detector is used for receiving the difference frequency laser to form a reference interference signal; The second photoelectric detector is used for receiving the reference light and the measuring light to form a measuring interference signal; The first polarized laser sequentially passes through the first beam splitter prism, the polarized beam splitter prism and the first plane reflector and then passes through the polarized beam splitter prism and the first beam splitter prism again to be used as reference light to enter the first photoelectric detector; The measuring light path comprises a first beam splitter prism, a polarization beam splitter prism, a quarter wave plate, a second plane reflecting mirror and a third plane reflecting mirror, wherein the second polarized laser sequentially passes through the first beam splitter prism, the polarization beam splitter prism, the quarter wave plate and the second plane reflecting mirror and then passes through the quarter wave plate again, the polarization state of the second polarized laser becomes horizontal polarization; Wherein the offset angle of the first plane mirror is zero, and the offset angle of the second plane mirror Is not zero, the offset angle of the third plane mirror is 2 ; Calculating the displacement of the object to be measured in the X direction of the two-dimensional plane based on the interference of the measuring light and the reference light And the displacement amount in the Y direction , wherein, Lambda R is the center wavelength of the difference frequency laser, A phase change is generated for the X-direction movement, A phase change is generated for the Y-direction movement, Is the offset angle of the second planar mirror.

Description

Single-mirror double-shaft displacement measurement method and device applied to scanning interference field Technical Field The application relates to the technical field of optical interferometry, in particular to a single-mirror double-shaft displacement measurement method and device applied to a scanning interference field. Background In the field of precision measurement, the laser interferometry displacement measurement technology is widely applied to nano-scale or even higher-precision detection of two-degree-of-freedom displacement in an object plane due to extremely high precision and resolution. Fig. 1 is a schematic diagram of a dual-mirror dual-axis displacement measurement device in the prior art, which is composed of an X-direction laser interferometer 01, an X-direction measurement mirror 03, a Y-direction laser interferometer 02, a Y-direction measurement mirror 04, and a workbench 05. Scanning interference field exposure is a key technology for manufacturing a large-size grating, wherein X-direction displacement reaches 650mm and Y-direction displacement reaches 1700mm in the manufacturing process of the large-size grating. By adopting the measurement principle of the X-Y double-mirror double-shaft displacement measuring device shown in FIG. 1, a Y-direction measuring mirror (weight is about 200 kg) with the length of 1700mm is required to be installed at the edge of the upper stage along the X axis. The measuring method has the technical defects that ① unbalanced load is additionally born, and the installation of the Y-direction measuring mirror can introduce asymmetric load for the workpiece table, so that the dynamic stability of the workpiece table is reduced, and the uniformity of the running speed of the workpiece table is influenced. ② The space occupation and operation obstacle is that the wider upper table surface and longer guide rail are required to be designed because of the larger volume of the Y-direction measuring mirror, and the operation flows of loading, mounting, unloading and the like of the grating substrate are seriously hindered. ③ The complexity of the system and the error accumulation are that the complexity of the optical and mechanical structures of the equipment is obviously increased, and a double-set laser interferometer along the X, Y axis is required to be deployed, so that the negative influence of zero point errors and integral accumulated errors on displacement measurement accuracy is not negligible. ④ Edge data loss for the position where the X-direction measurement mirror 03 and the Y-direction measurement mirror 04 overlap, the Y-direction laser interferometer 02 cannot acquire data, resulting in loss of measurement data. Due to the defects, a large amount of surface shape errors are introduced in the grating manufacturing process, so that the quality of the diffraction wavefront of the grating is suddenly reduced, and the use requirement cannot be met. Disclosure of Invention The application aims to provide a single-mirror double-shaft displacement measuring method and device applied to a scanning interference field, which can solve at least one technical problem. The specific scheme is as follows: The application provides a single-mirror double-shaft displacement measurement method applied to a scanning interference field, which comprises the following steps: Outputting a difference frequency laser with vertical orthogonal polarization, wherein the difference frequency laser comprises a first polarized laser with a first frequency and a second polarized laser with a second frequency, the first polarized laser is horizontally polarized, and the second polarized laser is vertically polarized; the first polarized laser is reflected by a first plane reflector and then is used as reference light to be injected into a first photoelectric detector, the second polarized laser is reflected by a second plane reflector and a third plane reflector and then is used as measurement light to be injected into a second photoelectric detector, wherein the offset angle of the first plane reflector is zero, and the offset angle of the second plane reflector is zero Is not zero, the offset angle of the third plane mirror is 2; Calculating the displacement of the object to be measured in the X direction of the two-dimensional plane based on the interference of the measuring light and the reference lightAnd the displacement amount in the Y direction, wherein, Lambda R is the center wavelength of the difference frequency laser,A phase change is generated for the X-direction movement,A phase change is generated for the Y-direction movement,Is the offset angle of the second planar mirror. In some embodiments, the second planar mirror has a bias angle of0.05 DEG to 1 deg. In some embodiments, the first polarized laser light is reflected by the first plane mirror and then enters the first photodetector as reference light, including: the first polarized laser is reflected by the f