Arrangement for and method of imaging targets with improved light collecting efficiency over extended range of working distances

An imaging lens assembly for an imaging reader includes a base lens having an optical power, a target side facing a target, and an imager side facing an imager. An aperture stop directly contacts the imager side and has an aperture through which return light from the target passes. The aperture is m...

Ausführliche Beschreibung

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Bibliographische Detailangaben
Hauptverfasser: Chinh Tan, Caihua Chen
Format: Patent
Sprache:eng
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Beschreibung
Zusammenfassung:An imaging lens assembly for an imaging reader includes a base lens having an optical power, a target side facing a target, and an imager side facing an imager. An aperture stop directly contacts the imager side and has an aperture through which return light from the target passes. The aperture is magnified in apparent size by the optical power of the base lens to form a magnified entrance pupil as seen through the target side. A variable focus liquid lens focuses the return light captured by the magnified entrance pupil over an extended range of working distances onto the imager. The magnified entrance pupil captures more of the return light from the target to pass through the base lens and the liquid lens to the imager, and also allows the target to be illuminated with a lower brightness to conserve electrical power.