Plan apochromatic metallographical microobjective with 5* long working distance and without CaF2

Abstract

The invention provides a plan apochromatic metallographical microobjective with a 5* long working distance and without CaF2. The plan apochromatic metallographical microobjective comprises lenses and is characterized in that the microobjective is composed of the convex lenses and the concave lenses, and the convex lenses and the concave lenses are made of optical glass without the CaF2, are seven in number altogether and are divided into four optical groups; all the lenses are coaxial with the center of an object plane and sequentially comprise the first convex lens, the second concave lens, the third concave lens, the fourth convex lens, the fifth concave lens, the sixth concave lens, the seventh convex lens and the object plane from left to right; the object plane is imaged at an infinite distance through an optical system. The plan apochromatic metallographical microobjective has the advantages that low power metallographical microobjective without the CaF2 achieves the plan apochromatic effect; the oversized field of view and the long working distance are achieved; the long parfocal effect of 60 mm is achieved; the cost performance is high.

Description

technical field [0001] The invention relates to a microscope objective lens, in particular to a CaF-free 2 5× long working distance plan apochromatic metallographic microscope objective. Background technique [0002] Microscopic objective lens is an important component of metallographic microscope, and its imaging quality directly affects the performance of metallographic microscope. The plan apochromatic microscope objective is the microscope objective with the best image quality and the highest grade. In order to correct axial chromatic aberration and secondary spectrum at the same time in the objective lens, the conventional method is to introduce optical crystals, such as calcium fluoride CaF 2 etc. as manufacturing materials; but there are very few special optical materials, they are brittle, their physical and chemical properties are unstable, and large-sized materials are more difficult to obtain. In recent years, some people use special glass (such as TF 3 ) to p...

AI Technical Summary

Problems solved by technology

In order to correct axial chromatic aberration and secondary spectrum at the same time in the objective lens, the conventional method is to introduce optical crystals, such as calcium fluoride CaF 2 etc. as manufacturing materials; but there are very few special optical materials, they are brittle, their physical and chemical properties are unstable, and large-sized materials are more difficult to obtain

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