Hand-held barcode label reader with increased depth of field
AssigneeReflexion Plus
InventorsJean-Louis Massieu, Jean-Michel Puech
Life of this patent
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Abstract
A barcode label reader comprises a read window having a longer dimension parallel to an X axis and a lens system with an optical axis Y substantially normal to the window at its center which projects a conjugate image of a read line of the label onto a CCD type strip which is scanned sequentially to form a signal representing the barcode carried by the label. A strip of light-emitting diodes is disposed outside the X-Y plane to illuminate the label through the read window. A prismlike lens in the form of two refractors separated by a slot in the X-Y plane deflects the beam emitted by this strip so that it is substantially parallel to the X-Y plane. Thus, the depth of field of the reader is limited only by the aperture of the lens system.
Claims5
Hand-held barcode label reader having an oblong rear window which is offered up substantially parallel to the label with a longer dimension transverse to the bars, the reader including a lens system with an optical axis near the normal to said window at its center and adapted to project a conjugate image of said label onto a photosensor strip comprising a plurality of receiver elements which are sequentially scanned electrically, arranged in a row in a sighting plane containing the optical axis and parallel to the longer dimension of said window, and a light source outside said sighting plane emitting towards said label through said window a beam spread out parallel to said longer dimension of said window, in which reader said beam passes through a prismlike lens with edges parallel to said longer dimension of said window and made up of two refractors disposed on respective opposite sides of a slot through which said sighting plane passes so that the emergent beam is substantially symmetrical relative to said sighting plane.
Dependencies are inferred from the claim text.