Mirau-type wide-field-of-view interference microscopic objective optical system

Abstract

The invention discloses a Mirau-type wide-field-of-view interference microscopic objective optical system. The system comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a reference board and a beam splitter board, which are arranged in sequence along the same optical axis. Illumination light passes through the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens and the reference board in sequence and is split into two beams by the beam splitter board, wherein one beam is incident to the surface of a reference flat plate and is reflected, and the other beam is incident to the surface of a member to be measured and is reflected; the two beams of emitting light are overlapped on the beam splitter board and interference occurs; and microscopic characteristics of the member to be measured is analyzed according to generated interference fringes. Magnification of the system is 0.5 X; numerical aperture is 0.015; entrance pupil diameter is 12 mm; focal length is 400 mm; parfocal distance is 280 mm; and field of view can reach 48 mm. The optical system is simple in structure and good in imaging quality, is suitable for coherent scanning interferometry and can be used for measuring three-dimensional shape of an uneven surface.

Description

technical field [0001] The invention belongs to the field of microscopic objective optical system design, and relates to a Mirau type wide field of view interference microscopic objective optical system. Background technique [0002] Interference microscope objectives are mainly used in the measurement of three-dimensional topography of microscopic surfaces. For example, non-contact profilers commonly used in industry and scientific research fields need to be used with interference microscope objectives of various magnifications. In the case of 2 / 3" CCD, when the tube lens is 1X, the line field of view of the 2.5X interference microscope objective is 9.3mm, the line field of view of the 10X interference microscope objective is 0.58mm, and the line view of the 20X interference microscope objective The field of view is 0.15mm, the linear field of view of the 50X interference microscope objective is 0.023mm, and the linear field of view of the 100X interference microscope objec...

AI Technical Summary

Problems solved by technology

However, since the smaller the magnification of the microscope objective lens, the larger the working distance, when designing an interference microscope objective lens less than 2X, the space occupied by the corresponding mechanical structure of the Michelson structure is too big to be practical

T.Dresel et al. proposed in the article "Three-dimensional sensing of roughsurface by coherence radar" published in AO that when the field of view is larger than 10mm, the excessive mechanical structure of the Michelson interference microscope objective makes it only applicable to specific Interferometer, and it is not flexible to switch other objective lenses, it is not advisable

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