Monochromator.

摘要

An Ebert monochromator e.g. for a spectrophotometer, in which the diffraction grating (18) is positioned of the central optical axis (17) of the collimator mirror (13) by interpositioning a plane mirror (15) between collimator mirror (13) and grating (18). The plane mirror may be movable to select one of several diffraction gratings. By arranging the diffraction grating about an axis (19) parallel with the central optical axis (17) a simple mechanical wavelength drive system with a common cam-shaft (30) driving the grating (18), a filter holder (36) and a rotatable slit plate, can be provided. Further gratings may be driven from the cam-shaft (30) as may the movable plane mirror which selects them.