Influence of Light Reflection at the Objective in the Quantitative Measurement of Reflectivity with the Microscope

Dr. rer. nat. Horst Filler
Laboratory of Microscopy, Messrs. Carl Zeiss, Oberkochen, Federal Republic of Germany

Summary: When the microscope is used in the measurement of reflectivity there is a glare effect, due to internal reflections from optical parts, for which corrections have to be made. In the present paper these effects are measured in a new series of objectives for reflected-light microscopes, and it is shown that the factors involved are the number, curvature, separation, and blooming of the lenses, along with the conditions of adjustment of the microscope. For a given objective the conditions producing the smallest glare are: small area of specimen illuminated and measured, high numerical aperture of the illuminating system, and adjustment of the illuminaton in such a way that the axis of the illuminating beams is slightly oblique. A theory of glare is outlined, and procedures for making the necessary corrections are described—by calculation and by graphical procedure. These corrections can be neglected when a sufficient number of graded standards is used.

Mineralogical Magazine; June 1967 v. 36; no. 278; p. 242-259; DOI: 10.1180/minmag.1967.036.278.07
© 1967, The Mineralogical Society
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