Heterodyne one/two-dimensional raster-displacement coarse/fine measurement system

Abstract

The invention discloses an heterodyne one / two-dimensional raster-displacement coarse / fine measurement system. The system comprises a single frequency laser light source, an electrooptic modulator, a one-dimensional reflection measurement raster, a beam splitter prism, five one-dimensional transmission measurement raster, six plane mirrors, four polarization splitting prisms, eight polaroids and eight photoelectric detection and signal processing components. The single frequency laser light source emits linear-polarization single frequency laser, a polarization direction and an x axis form 45 degree, the laser is modulated by the electrooptic modulator which is parallel to the x axis via a fast-axis direction and then a heterodyne laser is output. The heterodyne laser is formed by an s wave component whose polarization direction is along an z axis and a p wave component whose polarization direction is along the x axis. A phase difference which changes along with changes of a modulation voltage loaded by the electrooptic modulator exists between the s wave component and the p wave component. By using the system of the invention, errors caused by measured environment temperature and humidity changes and the like can be overcome, coarse / fine conversion of a displacement measurement resolution at a one / two-dimensional direction can be effectively realized and different measurement demands are fully satisfied.

Description

Technical field: [0001] The invention relates to a grating displacement measurement system, in particular to a heterodyne one / two-dimensional grating displacement coarse / fine measurement system. Background technique: [0002] Grating displacement measurement technology first originated in the 19th century and has developed rapidly since the 1950s. At present, the grating displacement measurement system has become a typical high-precision displacement measurement method, and is widely used in many opto-mechanical devices. Due to the advantages of high resolution, high precision, low cost, and low environmental sensitivity, the grating displacement measurement system has not only been widely used in industry and scientific research, but has also been studied by domestic and foreign scholars and scientific research institutions. [0003] In the fields of semiconductor technology, nanotechnology and biotechnology, precision displacement measurement systems and position position...

AI Technical Summary

Problems solved by technology

[0005] However, in all current research results on grating displacement measurement devices, the measurement resolution in the measurement process is a fixed value, that is, the same measurement resolution is used in both large-range displacement measurement and small-range displacement measurement. Realize the conversion of large-range displacement measurement using low-resolution rough measurement and small-range displacement measurement using high-resolution fine measurement, which will cause a waste of system resources

Moreover, since the measurement speed will limit the resolution of the system, that is, the higher the measurement speed, the lower the resolution of the system. Therefore, when high-resolution measurement is not necessary, the grating displacement measurement that cannot perform coarse / fine measurement conversion is still used. The device will limit the measurement speed of the system, thereby affecting the running speed of the motion device to be tested

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