Bar Code Scanner Lens Aperture
Original Publication Date: 1981-Jan-01
Included in the Prior Art Database: 2005-Feb-10
The bar code scanner consists of a system for illuminating an area on a coded document upon which a bar code pattern has been placed, and for imaging a portion of the area onto a photosensitive device in such a way that when the scanner is moved properly with respect to the coded pattern, electronic signals corresponding to the code pattern transitions are produced by the photosensor (P.S.). The imaging optical system is usually provided with lenses focusing the light reflected from the pattern into the photosensor. The degree to which light received by the photosensor is restricted to the desired area of the document is determined by lens quality and tolerances, and is strongly affected by displacement of the coded document from the point of best lens focus.