Transverse double-frequency zeeman laser linearity/coaxality measuring mechanism

Abstract

The present invention relates to precise laser meat technology. The measuring mechanism includes double-frequency laser light source; telescope, spectroscope, sleeve, two Wollaston prisms and right-angle prism set successively in the emitting light path of the laser; two polarization analyzers and two photoelectronic receivers in the reflecting light path of the spectroscope and right-angle prism; and one signal processing unit comprising signal amplifier, phase device and data processor. The present invention can eliminate the heat drift and non-linear error caused by the quarter wavelength plate principally. There is a pair of glass wedges mounted on the first Wollaston prism to correct the unsymmetry of the outgoing light relative to the incident light. A rotary signal receiver is adopted.

Description

technical field [0001] The invention belongs to the technical field of laser precision measurement, in particular to the application of laser for high-precision alignment. Background technique [0002] The measurement of straightness is one of the most basic measurement items in the field of geometric metrology. Long-distance straightness measurement is used in the installation and alignment of guide rails, the installation and positioning of large instruments, the manufacturing and testing of precision instruments, large-scale measurement, and military product manufacturing. Has a wide range of applications. In many projects, it is required to measure the coaxiality of multiple sets of shafts and holes, and it is required that the measurement can be carried out intermittently. Compared with the straightness, the coaxiality measurement puts forward higher requirements. [0003] Yin Chunyong of Tsinghua University proposed a method for measuring straightness / coaxiality using...

AI Technical Summary

Problems solved by technology

[0017] In order to obtain linearly polarized light, the device uses a quarter-wave plate. During the working process of the laser head, the temperature continues to rise, causing the thickness of the quarter-wave plate to change, which will cause drift in the measurement results. The wave plate has manufacturing errors, the phase delay is not strictly 90 degrees, and installation adjustment errors will affect the measurement results

In order to overcome the aforementioned shortcomings, the device thermally isolates the quarter-wave plate, and the internal structure of the laser head is designed to be more complicated.

Since the device uses a fixed sleeve, two sets of the same signal receiving devices must be used when measuring the straightness in the horizontal direction and the vertical direction, namely the second polarizer, the second photoelectric receiver and its signal amplification circuit and the third The polarizer, the third photoelectric receiver and its signal amplifying circuit, due to the different performances of different electronic components and the different debugging results of the signal amplifying circuit, the straightness measurement signals sent to the phaser in the horizontal direction and vertical direction It will be different, which will affect the consistency of the measurement results, and at the same time cause too many internal parts of the laser head, and the size is relatively large

There are manufacturing and installation errors in the Wollaston prism. When measuring, when the laser beam passes through the first Wollaston prism and is divided into two beams of light with a small angle (the two beams of light are not completely separated), the two beams of light The asymmetry relative to the original incident beam will cause the position of the light spot incident on the second Wollaston prism to shift, which will affect the measurement accuracy

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