Laser straightness and displacement measuring device

Abstract

The invention discloses a laser straightness and displacement measuring device comprising a dual-frequency laser light source and a normal beam splitter. A first light path retracing reflector is arranged on a measuring light path of the normal beam splitter, a first Wollaston prism, a second Wollaston prism and a benchmark reflector are arranged on a first reflecting light path of the first light path retracing reflector in sequence, the second Wollaston prism, the first Wollaston prism and the first light path retracing reflector are further located in a light path of return light reflected from the benchmark reflector in sequence, a polarizing beam splitter is arranged on a second reflecting light path of the first light path retracing reflector and also located in a reference light path of the normal beam splitter, an analyzer and a photoelectric receiver are arranged in each of two emergent directions of the polarizing beam splitter in sequence, and the two photoelectric receivers are connected to a signal processing unit. The device is capable of completing measurement of straightness and displacement simultaneously, equipment cost is lowered, adjustment process is simplified, testing efficiency is improved, and measurement accuracy is guaranteed.

Description

technical field [0001] The invention belongs to the technical field of laser precision measurement, in particular to a device for straightness measurement and displacement measurement using laser. Background technique [0002] Displacement measurement and straightness measurement are the most basic measurement items in the field of geometric measurement, and are widely used in the accuracy verification and error compensation of moving guide rails, coordinate measuring machines, machine tools and other equipment. [0003] Among the laser interference straightness measurement schemes, the single Wollaston prism scheme adopted by Agilent Corporation of the United States was the first, and it is still sold as a commercial device. The disadvantage is that two sets of devices are required to measure the working distance of 0-30 meters. The angles of the Raston prism and the large-angle flat mirror need to be processed in pairs, which is difficult to process, high in cost, and diff...

AI Technical Summary

Problems solved by technology

[0003] Among the laser interference straightness measurement schemes, the single Wollaston prism scheme adopted by Agilent Corporation of the United States was the first, and it is still sold as a commercial device. The disadvantage is that two sets of devices are required to measure the working distance of 0-30 meters. The angles of the Raston prism and the large-angle flat mirror need to be processed in pairs, which is difficult to process, high in cost, and difficult to adjust

However, since the large-angle measuring mirror is not only the measurement reference of straightness, but also the target mirror to be measured, it needs to be moved during the measurement process.

When measuring straightness in the vertical direction, changes in the pitch angle of the target mirror will directly cause the rotation of the straightness reference line, resulting in additional measurement errors; when measuring straightness in the horizontal direction, changes in the yaw angle of the target mirror will directly cause the rotation of the straightness reference line. rotation, resulting in additional measurement error

The pitch, yaw, and roll of the target mirror will also cause the offset of the returned light, so that the beams cannot overlap or leave the receiving window of the photoelectric receiver, resulting in a decrease in signal amplitude and contrast, and in severe cases, the measurement will be interrupted

Therefore, there are problems in practical applications, especially in long-distance use

In addition, the device also has defects such as high requirements for device pairing processing in the single Wollaston measurement system, high difficulty, and difficult adjustment.

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