The add-on halogen illuminator was built specifically for use with either the Nikon model S-Ke or L-Ke microscopes, both of which were manufactured during the late 1960s and early 1970s. Already equipped with a binocular head and mechanical stage, the additional illumination provided by the halogen lamphouse boosted these microscopes onto front stage of the research arena.
The extremely bright iodide (halide) lamp provided a convenient method of completely filling the objective rear aperture and of attaining outstanding results with Köhler illumination. In addition, the external lamp house was easily attached and detached from the microscope and the halogen bulb and lamp socket were similarly easy to replace, providing a high degree of convenience for the microscopist. Unlike the conventional tungsten lamps of the period, the Nikon add-on tungsten-halide lamp required less than 12 volts, which reduced excess illumination and provided a longer bulb life. Knobs on the external portion of the lamp house allowed the user to adjust the lamp orientation in three directions: vertical, lateral, and along the optical axis. These adjustments provided for exact alignment of the lamp axis to coincide with the optical axis of the microscope.