Nanometer-resolution total-reflection differential micrometric displacement measurement method and device

Abstract

The invention discloses a nanometer-resolution total-reflection differential micrometric displacement measurement method and a nanometer-resolution total-reflection differential micrometric displacement measurement device. The device comprises a laser, a single mode fiber, a collimating lens, a depolarization spectroscope, a micro objective, a measured target mirror, a rhombic prism, a convex lens, a differential detector and a driving and display unit. The method comprises that: laser is filtered and collimated, and the filtered and collimated laser is vertically incident onto the depolarization spectroscope; the filtered and collimated laser sequentially passes through the micro objective to reach the measured target mirror, is reversely reflected, refracted by the micro objective and vertically incident into the depolarization spectroscope, enters the rhombic prism, and is totally reflected for at least once in the rhombic prism and emergent; and emergent light beams are converged and incident into the differential detector, signals are transmitted into a driving and display system of the detector to obtain voltage signals reflecting the position changes of the measured target mirror, and the position changes of the measured target mirror are displayed. The method and the device can be used for nanometer-resolution detection, and are widely applied in the field of industrial precision measurement and monitoring.

Description

technical field [0001] The invention belongs to the technical field of photoelectric detection, and in particular relates to a method and a device for high-precision micro-displacement measurement and monitoring. Background technique [0002] Today, nanotechnology, biotechnology, and high-end integrated circuit manufacturing technology have become important directions for the development of world science and technology. Fast and reliable nanoscale resolution detection technology plays an extremely important role in the research of nanotechnology, biotechnology, high-end integrated circuit manufacturing and other fields. The traditional microscopic measurement technology based on light interference has been able to obtain measurement resolutions as high as below 1nm. At present, the optical non-interference method for micro-displacement measurement is the most successful confocal method. The traditional confocal method is to use the point light source, the object to be measu...

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Problems solved by technology

However, its resolution is limited by the size of the pinhole and the numerical aperture of the microscope objective, and is affected by the fluctuation of the external background and the light source itself.

In order to improve its axial resolution, in the Chinese patent No. 200510123581.9, Zhao Weiqian and others proposed the idea of ​​differential confocal, using two receiving holes to stagger a certain position from the focal plane in the axial direction, and passing through The light intensity behind the two small holes is then differentially processed, which improves the axial resolution and eliminates the influence of optical power fluctuations and background noise on the measurement, but it requires two small holes, two detectors and relative adjustments Complex and thus expensive system

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