Patent ID: 6860424

Claim:
An optical reader for reading a symbol representing information having areas of different light reflectivity, the reader comprising: a radiant energy source for generating a radiant energy for illuminating a target region as a spot illumination; a photodetector for generating output electrical signals indicative of the radiant energy incident thereon; an optical system having a projection portion for directing the radiant energy along a projection path extending from the radiant energy source to the target region at a fixed angle to the surface thereof such that light reflected therefrom is directed along the longitudinal axis in a diverging manner; a collection portion for collecting the radiant energy reflected from a symbol along the longitudinal axis when the symbol occupies the target region and directing the collected radiant energy along a collection path extending from the target region to the photodetector along the longitudinal axis as a column of parallel rays, the collection portion including: one pinhole aperture disposed upstream and parallel to the collection path from the photodetector without intervening refraction or diffraction and centered along the longitudinal axis; and one magnifying lens disposed upstream on the collection path from the pinhole aperture without intervening refraction or diffraction for collimating reflected light perpendicular to the aperture and along the longitudinal axis; and a decoder for decoding the output electrical signals of the photodetector to provide an indication of the information contained in the symbol.