Abstract: An improved sample holder for a spectrophotometer includes a stationary base that forms a cylindrical cavity and supports a fiber optic head assembly over the cavity for analyzing the color of a sample that is positioned adjacent the base and under the cavity. The fiber optic head assembly covers the top of the cavity and the area of the sample that is to be color analyzed is not visible to an operator of the spectrophotometer. A shutter mechanism is arranged to be moved in an opening in the base between a closed position in which the shutter forms part of the cylindrical wall of the aperture and an open position in which the opening in the base permits an operator to view the sample. A prism is provided to raise the viewing position of the operator to the normal position of the operator.

Abstract: This monochromator is made up of a number of discrete narrow band interference filters mounted on a drum which rotates with respect to a light beam so that as the light beam passes through each of the filter the angle of incidence of the light beam changes with respect to the filter. Each of the filters is for a different normal wavelength of peak transmission so that spectral analysis of the light source can be obtained.

Abstract: An article handler or positioner includes an X-Y table driven by reversible stepping motors. Zero position sensors function to provide an output signal when the X-Y table moves into a zero or home or reference position. The sensors are electro-optical devices having two beams of light one of which is gradually interrupted while the other one is gradually uninterrupted as the table moves into the zero position. Photo detectors provide output signals one of which increases and the other of which decreases as the table moves into the zero position and, at the point of crossover of the respective output signals, another output signal is generated indicating the home position is reached. This signal is then used to inhibit further operation of the driving motors.

Abstract: A thin flat circular silicon wafer is mounted or supported by a wafer holder mounted on an X-Y table. Motive means drives the table in two different linear directions so as to selectively position different areas of the wafer beneath a test probe. A plurality of wafer chips are also mounted on the table at different positions locatable beneath the test probe. Each of the wafer chips has different characteristics suitable for use in calibrating the test system. The wafer chips are located at predetermined positions relative to a reference position so that the table can be automatically moved during calibration to present the wafer chips to the test probe.