Unique Optical System For Conversion Of Existing Photometers Into Scanning Microphotometers

There are many thousands of luminance photometers in the field, both telephotometers and microphotometers; however, very few of these have scanning microphotometric capability. This paper describes a unique optical system that can be field-interchanged with the standard objective lens, without requiring any modification of the photometer's internal optical system, to convert an existing photometer into a high-resolution scanning microphotometer. One embodiment, called the MicroScanner Spatial Scanner, will be described in detail. Used with any standard Pritchard Photometer, this scanner provides variable-speed scanning of a half-inch (12 mm) of object space with field coverage as fine as 0.0001 in. (0.0025 mm) or as broad as 0.39 in. (10 mm). The system features photometric uniformity within +/-0.5% over the entire scan distance, freedom from polarization error, and a half-inch scan distance independent of choice of objective lens.