a caf free 2 10× long working distance plan apochromatic metallographic microscope objective

Abstract

The invention discloses a long-work-distance flat-field apochromatic metallographic microscope objective with magnification power being 10 and without CaF2. The metallographic microscope objective is composed of 8 optical glass convex lenses and concave lenses without the CaF2, and the convex lenses and concave lenses are divided to five optical groups. All the lenses are coaxial with the center of an object plane, and the first convex lens, the second concave lens, the third concave lens, the fourth concave lens, the fifth convex lens, the sixth concave lens, the seventh concave lens, the eighth convex lens and objective plane are sequentially arranged from left to right. The objective plane forms an image at a infinitely remote place after passing through a system. The work distance W.D of the microscope objective is 17.3 mm, the magnification power beta is 10 (when the microscope objective is used in cooperation with a tube lens with the f' being 200 mm), the focal length f' is 20 mm, the numerical aperture NA is 0.28, and the aperture angle omega is 3.15 degrees (when the image side visual field phi is 22 mm). The metallographic microscope objective has the advantages that the medium-expansion metallographic microscope objective without the CaF2 achieves the flat-field apochromatic effect, a large visual field and a long work distance are achieved, a high performance cost ratio is achieved, and the parfocal length of the metallographic microscope objective is large and is 60 mm.

Description

technical field [0001] The invention relates to a microscope objective lens, in particular to a CaF-free 2 10× long working distance plan apochromatic metallographic microscope objective. Background technique [0002] Microscopic objective lens is the most important part of metallographic microscope, and its imaging quality directly affects the performance of metallographic microscope. The plan apochromatic microscope objective is the one with the best image quality and the highest grade. In order to correct the primary axial chromatic aberration and the secondary spectrum at the same time in the objective lens, the conventional method is to introduce an optical crystal with low refractive index and low dispersion in part of the positive lens; Stable, large-sized materials are more difficult to obtain. The German Leica objective lens of similar foreign products is composed of 7 lenses, and the Olympus objective lens is composed of 6 lenses, all of which use CaF 2 materia...

AI Technical Summary

Problems solved by technology

Of course, the long parfocal structure brings new challenges to the design and manufacture of objective lenses and opportunities to achieve innovative results

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