A New Incident Illuminator for Polarizing Microscopes

F. H. Smith
Vickers Instruments Ltd., Purley Way, Croydon, Surrey

Summary: The customary illumination by a ‘coverglass’ inclined at 45 degrees is replaced by a double reflection. The beam from the horizontal collimating tube is first reflected from a highly reflecting mirror at the back of the unit, then downward from a coverglass placed at the top of the unit. With this arrangement the coverglass is inclined at less than 2212 degrees to the axis of the microscope, with a similar reduction of the angle of incidence. The correction ratio for rotation by upward passage of light through the coverglass is now reduced from 6:5 to the almost negligible value 21:20. There is a corresponding improvement in the homogeneity of extinction over the microscope field.

Mineralogical Magazine; March 1964 v. 33; no. 264; p. 725-729; DOI: 10.1180/minmag.1964.033.264.01
© 1964, The Mineralogical Society
Mineralogical Society (www.minersoc.org)