Flat-field apochromatic metallographic microscope objective with magnification power being 40 and without CaF2

Abstract

The invention discloses a flat-field apochromatic metallographic microscope objective with magnification power being 40 and without CaF2. The metallographic microscope objective is composed of 8 lenses divided into 3 groups. The work distance W.D. of the microscope objective is 0.15 mm, the magnification power is 40, the numerical aperture is larger than 0.7, the aperture angle omega is larger than 2 degrees, and the effective focal length f' is 6.27 mm. The metallographic microscope objective can be widely applied to various metallographic microscope devices, and has the advantages that the metallographic microscope objective without the CaF2 achieves the flat-field apochromatic effect, a high performance cost ratio is achieved, and the structure is simple.

Description

technical field [0001] The invention relates to a microscope objective lens, in particular to a CaF-free 2 40× 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, brittle, unstable physical and chemical properties, and large-sized materials are more difficult to obtain. "Handbook of Practical Optical Technology" (2006, Beijing: Machinery Industry Press) edited by Wang Zhijiang...

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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, brittle, unstable physical and chemical properties, and large-sized materials are more difficult to obtain

"Handbook of Practical Optical Technology" (2006, Beijing: Machinery Industry Press) edited by Wang Zhijiang mentioned a domestic similar 40× plan achromatic microscope objective lens, which consists of 7 lenses, 2 of which use low refraction FK series glass with low rate, high cost

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