Optical device for sensing marks on a surface using green light impinging at least sixty-five degrees to the normal
AssigneeInternational Business Machines Corporation
InventorsDavid A. Droge, Ralf Fischer, Marcus Spieth
Life of this patent
Estimating the term…
Abstract
An optical device for sensing marks carried on an area to be sensed of a medium, especially printed and/or handwritten patterns, is disclosed. Sensing of marks is accomplished by inclined illumination of the area to be sensed by a light source (3) emitting shortwave light, especially in the green spectral area, and reception of reflected light by a photoreceptor (4).
Claims15
An optical device for detecting marks on an area of a medium, comprising:
- at least a first light source which is capable of emitting green light;
- a photoreceptor which is capable of receiving green light reflected from said area;
- and
- light guide means, positioned so as to be capable of optical communication with said at least first light source, said area and said photoreceptor, for guiding at least a portion of the green light emitted by said at least first light source to said area at an angle of incidence, relative to the plane of said area, less than 35 degrees and for guiding at least a portion of the green light reflected by said area to said photoreceptor.
A method for detecting marks on an area of a medium, comprising the steps of:
- impinging green light on said area at an angle of incidence, relative to the plane of said area, less than 35 degrees;
- and
- receiving green light substantially normally reflected from said area with a photoreceptor.
An optical device for detecting marks on an area of a medium, comprising:
- means for impinging green light on said area at an angle of incidence, relative to the plane of said area, less than 35 degrees;
- and
- a photoreceptor which is capable of receiving green light reflected from said area.
Dependencies are inferred from the claim text.