title: Compensator transducer increases ease, accuracy, and rapidity of measuring changes in specimen birefringence with polarization microscopy.
abstract: An instrument has been designed to improve substantially the efficiency and convenience of measuring specimen birefringence retardation (BR) with a conventional Brace-Köhler compensator. The design is based on the precise transduction of the angular position of the compensator's Vernier dial to an easily visible red-illuminated display on a digital voltmeter. The instrument display is accurate to within 0.1 degrees over a range of +/-25 degrees in the compensator vernier dial position which is similar to the precision obtainable with an ordinary vernier and the Brace-Köhler method of measuring BR of biological specimens. For convenience in data reduction the display can also be read directly in nanometre units, with a similar precision for specimen BR in the range of 5 nm or less which is typical of birefringent fine structures in living cells.
mesh_terms: D001718:Birefringence; D008859:Microscopy, Polarization / Q000295:instrumentation*; D014159:Transducers