Major-minor phase discriminator based subdivision method of dual-frequency laser interferometer

A technology of dual-frequency laser interferometry and laser interferometer, applied in instruments, optical devices, measuring devices, etc., can solve the problems of limited frequency multiplication phase-locked bandwidth, center frequency reduction, digital demodulation limitations, etc., and achieve high resolution , the effect of fast measurement speed

Inactive Publication Date: 2009-07-08
西安秦川思源测量仪器有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the frequency tracking bandwidth of frequency multiplication phase locking is limited, and the control of digital demodulation is limited by high-frequency work
Transverse Zeeman laser is used, the center frequency is reduced, and high-magnification phase-locked frequency doubling can be realized, but the measurement speed is limited

Method used

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Comparison scheme
Effect test

Embodiment 1

[0023] A subdivision method based on primary and secondary phase detectors for a dual-frequency laser interferometer, comprising the steps of:

[0024] The first step is to preprocess the reference and measurement photoelectric signals of the laser interferometer. After shaping, they become two square wave signals, namely Fr and Fm. These two square wave signals Fr and Fm are directly input to the reversible counter for processing. Acquisition of the whole cycle signal; at the same time, divide the two square wave signals Fr and Fm by 8, that is, Fr_8 and Fm_8, input Fr_8 and Fm_8 to the main phase detector for fractional cycle acquisition, and then perform π / 2 After the phase shift, Fr_8s and Fm_8 are input to the auxiliary phase detector and also collect fractional periods, thus forming a data acquisition system composed of a main and auxiliary phase detector and a reversible counter.

[0025] The above functions are realized by the hardware of the system. The counter adop...

Embodiment 2

[0038] A subdivision method based on primary and secondary phase detectors for a dual-frequency laser interferometer, comprising the steps of:

[0039] The first step is to preprocess the reference and measurement photoelectric signals of the laser interferometer. After shaping, they become two square wave signals, namely Fr and Fm. These two square wave signals Fr and Fm are directly input to the reversible counter for processing. Acquisition of the whole cycle signal; at the same time, divide the two square wave signals Fr and Fm by 8, that is, Fr_8 and Fm_8, input Fr_8 and Fm_8 to the main phase detector for fractional cycle acquisition, and then perform π / 2 After the phase shift, Fr_8s and Fm_8 are input to the auxiliary phase detector and also collect fractional periods, thus forming a data acquisition system composed of a main and auxiliary phase detector and a reversible counter.

[0040] The above functions are realized by the hardware of the system. The counter adop...

Embodiment 3

[0053] A subdivision method based on primary and secondary phase detectors for a dual-frequency laser interferometer, comprising the steps of:

[0054] The first step is to preprocess the reference and measurement photoelectric signals of the laser interferometer. After shaping, they become two square wave signals, namely Fr and Fm. These two square wave signals Fr and Fm are directly input to the reversible counter for processing. Acquisition of the whole cycle signal; at the same time, divide the two square wave signals Fr and Fm by 8, that is, Fr_8 and Fm_8, input Fr_8 and Fm_8 to the main phase detector for fractional cycle acquisition, and then perform π / 2 After the phase shift, Fr_8s and Fm_8 are input to the auxiliary phase detector and also collect fractional periods, thus forming a data acquisition system composed of a main and auxiliary phase detector and a reversible counter.

[0055] The above functions are realized by the hardware of the system. The counter adop...

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Abstract

The invention relates to a method for subdividing dual-frequency laser interferometers on the basis of a main phase discriminator and an auxiliary phase discriminator, which comprises the following steps: firstly, pretreating two paths, namely a reference path and a measurement path, of photoelectric signals of the laser interferometer, inputting the photoelectric signals into a reversible counter for signal acquisition, performing eight frequency division on the pretreated signals, inputting the signals into the main phase discriminator for data acquisition, performing phase shift on models of the reference path, and inputting the models of the reference path with Fm_8 into the auxiliary phase discriminator for data acquisition; secondly, resetting the reversible counter, and making an initial phase angle of the main phase discriminator operated within an interval of 0.5+/-0.125 and a phase angle of the auxiliary phase discriminator operated within an interval of 0.62+/-0.125; thirdly, making a CPU enter a sampling interruption program when a timing signal arrives to latch data; fourthly, performing error judgment on the data acquired in the third step; and fifthly, performing error elimination and synthesis on the data. The dual-frequency laser interferometers have the characteristics of quick measuring speed, high resolution and multi-frequency phase locking frequency tracing bandwidth during actual measurement.

Description

technical field [0001] The invention relates to a phase subdivision method of a laser interferometer, in particular to a subdivision method of a dual-frequency laser interferometer based on a main and auxiliary phase detector. Background technique [0002] The dual-frequency laser interferometer can achieve high-magnification subdivision and high measurement resolution through the principles of optics and electronics. Only relying on the optical system, ordinary interferometers can only achieve half-wavelength resolution, that is, on the order of 0.1 μm. The current interferometer improves the measurement resolution through electronic subdivision. Products from foreign companies such as Agilent and ZYGO can achieve 2048 Subdivision, the maximum resolution reaches 0.15nm. At present, there is no good instrument in China as a benchmark for nanoscale measurement. [0003] Realization of laser high-resolution measurement: The high-resolution of laser interferometer is realized...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01B9/02
Inventor 郭俊杰
Owner 西安秦川思源测量仪器有限公司
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