Abstract: An autofocus mechanism for a microscope comprises an arrangement of optical elements aligned along a single optical path. The arrangement includes a single illumination source which provides both a viewing component and a positioning component. Included in the autofocus arrangement are optical elements to eccentrically reference the positioning component for determining the focus condition of the instrument. The autofocus arrangement also includes a detector for determining the degree of eccentricity of the measuring ray and to make adjustments in the microscope according to this eccentricity to bring the viewed object into focus.

Abstract: A pair of horizontal rods of fiber optic bundles extend into a light box from external high intensity light sources. Light from the rods is directed upwardly via fixed mirrors, and thence horizontally and vertically to a viewing plate via pairs of mirrors supported in rotatable arms. Secured in the mirror arms are bearings that are rotatable in support plates, the axes of such bearings being coaxial with respective rhomboid arms. The mirror arms are caused to track the movements of the rhomboids, and different arrangements are disclosed for effecting such tracking, including external motors having shafts coupled via gears to the bearings and a servo control network with inputs from potentiometers representing the relative positions of the mirror arms and the rhomboids coaxial thereto, and pulleys and belt arrangement extending between coaxial arms.