Optical doubling frequency laser interference measurement system and optical doubling frequency laser interference measurement method for displacement of special geometric point

Abstract

The invention belongs to the field of optical measurement and relates to an optical doubling frequency laser interference measurement method for the displacement of a special geometric point. The method comprises the following steps: symmetrically placing two pyramid prisms on two sides of a special geometric point on a measured object; accurately obtaining the displacement of a central point by utilizing the displacement sum of two points; and dividing laser output light into measurement light and reference light by utilizing a polarization light splitter, wherein the measurement light respectively passes through the two pyramid prisms and returns twice in each pyramid prism and the measurement light moves for 8 Delta if a measured point moves for one Delta so that the optical octuple frequency of interference measurement is realized and the measurement accuracy is improved. Because the measurement light returns along the prior path in the pyramid prisms, even if the measured object moves in a plane vertical to a motion direction according to the characteristics of the pyramid prisms, the measurement accuracy of the motion direction is not influenced so that the method can be more widely applied. The invention can be applied to the measurement of non-guide rail movement and other complicated movements with more measured object freedom.

Description

technical field [0001] The invention belongs to the field of optical metrology, and relates to an optical frequency-doubled laser interferometry method for displacement of a special geometric point, which is suitable for a special geometric point where the measured point is a measured object. For example, the measured object is hollow and the measurement point is blocked. or sensitive areas. Background technique [0002] Since the advent of the laser in 1958, coupled with the development of modern microelectronics technology, the laser interferometer has become one of the most accurate length and position measurement devices. With the discovery of the polarization characteristics of the laser, the polarization laser interferometer has been applied in high-resolution In force displacement measurement, it has the characteristics of high light application efficiency; the principle of a typical Michelson polarization laser interferometer is to divide a beam of circularly polariz...

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Problems solved by technology

[0002] Since the advent of the laser in 1958, coupled with the development of modern microelectronics technology, the laser interferometer has become one of the most accurate length and position measurement devices. With the discovery of the polarization characteristics of the laser, the polarization laser interferometer has been applied in high-resolution In force displacement measurement, it has the characteristics of high light application efficiency; the principle of a typical Michelson polarization laser interferometer is to divide a beam of circularly polarized laser light into P light and S light through a polarization beam splitter PBS, which are reflected by a reference mirror and a moving reflection Mirror and quarter-wave plate return to the original path, and meet again at the split point, and finally form interference, in which the moving mirror is often integrated with the measured object. When measuring, the measured object must move along the guide rail. The point to be measured is often where the moving mirror is located, and it cannot be accurately measured for special geometric points

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