Four-freedom degree optical measuring head based on semiconductor laser assembly

Abstract

The invention relates to a four-degree-of-freedom optical measuring head based on semiconductor laser components. Including the probe mechanism and the target mirror mechanism; the probe mechanism includes semiconductor lasers, four-quadrant photodetectors, two-dimensional PSD position sensitive detectors, optical isolators and plano-convex lenses; the target mirror mechanism includes half-transparent mirrors and corner cubes; When used for measurement, the measuring head mechanism is fixed on the workbench, and the target mirror mechanism is fixed on the main shaft of the power head. The light beam emitted by the semiconductor laser is divided into two beams after passing through the polarizing beam splitter. One of the beams is incident on the half-mirror, and 50% of the light will pass through the half-mirror and enter the corner-cube prism, and then pass through the corner-cube prism. Reflected onto the four-quadrant detector, it is used as a reference beam for measuring two-dimensional linear displacement X, Y. The other half of the beam incident on the half-mirror will return along the original path and enter the beam splitter again, be reflected vertically to the plano-convex lens, and then be collimated and focused on the two-dimensional PSD by the plano-convex lens, which is used as the angle error (pitch angle , deflection angle) of the reference beam.

Description

technical field [0001] The invention belongs to the technical field of optical non-contact micro-angle measurement, and in particular relates to a four-degree-of-freedom optical measuring head device based on a semiconductor laser component. Background technique [0002] The measurement of small displacement and small angle is an important part of geometric measurement, and it plays an extremely important role in many fields such as precision machining, micro-electromechanical system, online detection, military, aviation, navigation, and communication; and the measuring head is used to measure these physical quantities. One of the key components. Precision probes are divided into two types: contact type and non-contact type. Non-contact optical probes have attracted more and more attention because of their characteristics of non-contact, non-damage, high precision and high sensitivity. attention and development. [0003] The most commonly used multi-degree-of-freedom real-...

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Problems solved by technology

[0003] The most commonly used multi-degree-of-freedom real-time monitoring system uses laser interferometers, such as HP5529A dynamic correction device, Renishaw and Zygo laser measurement systems, which have high measurement accuracy, but only one error is measured once installed, and the detection process is cumbersome and long; Researchers from Nihou University and Sophia University in Japan have studied an optical measurement system for simultaneously measuring multi-degree-of-freedom errors of machine tool workbenches, but the measuring head is large in size and needs to be installed on a movable platform, which limits the scope of application and is expensive, which is not conducive to popularization; The position and attitude measurement system researched by the Taiwan Institute of Aeronautics and Astronautics is based on the principle of area array CCD, which can obtain the position and attitude information of the surface feature points of the measured object. The system structure and hardware control are very complicated, which increases the difficulty of installation and adjustment; now there are The multi-degree-of-freedom laser interferometer of API Company is sold, but its price is extremely expensive. If it is widely popularized, the cost will be too high; with the wide application of semiconductor lasers, Zhejiang University proposed a two-dimensional micro-interferometer based on laser self-collimation. The angle measurement device uses semiconductor lasers and four-quadrant detectors to achieve accurate measurement of two-dimensional angles, but it can only measure two-dimensional angle errors, and its practical application is limited; then Professor Lu Rongsheng of Hefei University of Technology developed a cheap DVD-based The autofocus probe of the laser head is used for the measurement of normal displacement and two-dimensional angle. It basically achieves the characteristics of small size and low price, but its measurable amount is still not much, and it can only realize the error measurement of three degrees of freedom.

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