Method and apparatus of fine distribution of white light interference sample surface shapes

Abstract

The invention relates to a method and a device for measuring fine distribution of sample surface shape by white-light interferometry. The method comprises the following steps: respectively projecting a white light beam on the surfaces of a sample and a reference mirror; combining the reflected light beams of the two surfaces to obtain one beam, and projecting the beam on the photosensitive surface of a CCD camera to obtain interference fringe; and changing the pitch between the sample and an objective lens to form a plurality of interference images on the photosensitive surface, inputting the interference images into a computer to obtain the cosine distribution of amplitude modulation signals relevant to spectral distribution of a light source, sampling the discrete values of the plurality of amplitude modulation signals by an unequal interval sampling method, and calculating the relative height of the sample surface. The measurement device is composed of the light source, a transflective spectroscope, the CCD camera, an interference microscope objective lens, a sample stage, etc., wherein the spectroscope divides the light beam of the light source into a reflective beam and a transmissive beam; the CCD camera and the interference microscope objective lens are respectively arranged on a transmissive optical axis and a reflective optical axis; the CCD camera is control-connected with a computer; and the interference microscope objective lens can be controlled by the computer to make up-and-down movement.

Description

technical field [0001] The content of the present invention belongs to the technical field of optical fine measurement, and relates to an optical non-contact measurement method and its device, in particular to a measurement method and its device for measuring the fine distribution of the surface shape of a sample by using the principle of white light interference. Background technique [0002] In recent years, with the progress and development of precision manufacturing technology, the technology of using light interference method and its device to detect the surface shape of objects, especially the surface shape of precision optical flat objects, has been widely used. At present, the optical interferometry methods known to users in this field mainly include two types of interferometer measurement methods, single-wave interferometer and multi-wave interferometer, but they are used to measure the surface shape distribution of test objects or samples with optical planes. When ...

AI Technical Summary

Problems solved by technology

At present, the optical interferometry methods known to users in this field mainly include two types of interferometer measurement methods, single-wave interferometer and multi-wave interferometer, but they are used to measure the surface shape distribution of test objects or samples with optical planes. When performing very high-precision measurement, correspondingly, there are problems such as long data sampling time, poor anti-interference ability of the instrument itself, and low measurement accuracy and working stability.

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