Compact spectrophotometer

摘要

A portable spectrophotometer includes a rotating wheel provided with a plurality of filters having filter characteristics in the 400 to 700 nanometer wavelength range. The filters are moved between an optical conduit and a photoelectric sensor as the wheel is rotated. In one embodiment, a lamp housing contains three object illuminating lamps circumferentially spaced apart by 120 DEG and projecting light onto the object sample at a 45 DEG angle to the object sample. Light reflected from the object sample is conducted through the optical conduit and focused on the optical sensor by means of a focusing lens. A blocking filter is interposed between the lens and the wheel and serves to block light outside of the 400 to 700 nanometer wavelength range. A side sensor receives light from one of the three lamps through the filters as the wheel is rotated and provides output signals which are used as reference signals for the individual filters. In another embodiment, the spectrophotometer includes an integrating sphere with an aperture for conducting specular-included light reflected from the object and an aperture for conducting specular-excluded light from the object. The integrating sphere spectrophotometer also includes a rotatable filter wheel, with a plurality of filters having filter characteristics in the 400 to 700 nanometers wave length range. A side sensor is also provided with the integrating sphere spectrophotometer. As the wheel is rotated, specular-included and specular-excluded light from an object sample to be tested is projected simultaneously through apertures of the sphere. Light detected by a side sensor is also simultaneously detected through one of the filters of the filter wheel. The integrating sphere spectrophotometer also includes an arrangement for providing calibration and compensation of reflectance measurements.