Optical head for an optical authenticity identifing system

摘要

A highly simple and compact optical head for optically determining authenticity of an article by impinging a light beam upon an identification region provided on the article and having a selected reflective directivity, and receiving light reflected by the identification region. The identification region may consist of a holograph, a diffraction grating or a multiplicity of parallel grooves. The optical head comprises a light emitting element fixedly secured to a casing and a light receiving element placed coaxially in a light path of a light beam emitted from the light emitting element and having an opening for allowing the light beam to pass through the light receiving surface facing away from the light emitting element and being divided into a plurality of sectors defined around an axial center line of the light emitting element with each of the sectors being capable of individually detecting a magnitude of light impinging thereon.