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US 6,712,270 B2Granted
Positioning of photodetectors in optical scanning modules for use in bar code readers for reducing specular reflection
AssigneeSymbol Technologies, Inc.
InventorRobert J. Leach
Life of this patent
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Abstract
An optical scan module includes a scanner for scanning a scanning beam over a target plane at which indicia to be electro-optically read is located, and a pair of spaced-apart detectors for sensing light reflected from the indicia over respective fields of view. The detectors have optical axes intersecting each other, generate respective electrical signals indicative of the indicia, and are connected to a multiplexer for selectively acquiring one of the signals based on the direction of the scanning beam. The acquired signal is decoded by a decoder.
Claims8
An optical scan module, comprising:
- a) a support;
- b) a light source on the support for emitting a light beam;
- c) a scanner on the support for scanning the light beam in a scan direction over a target plane at which indicia to be electro-optically read is located for reflection from the indicia;
- d) a first detector on the support, and operative for sensing light reflected from the indicia over a first field of view and for generating a first electrical signal indicative of the indicia, the first detector having a first optical axis extending to the target plane within the first field of view;
- e) a second detector on the support and spaced away from the first detector, and operative for sensing light reflected from the indicia over a second field of view and for generating a second electrical signal indicative of the indicia, the second detector having a second optical axis extending to the target plane within the second field of view, the first and second optical axes intersecting each other;
- f) a multiplexer connected to the detectors for selectively acquiring one of the electrical signals as a function of the scan direction of the light beam;
- and
- g) a decoder connected to the multiplexer for decoding the acquired one of the electrical signals.
5 more elements
Dependencies are inferred from the claim text.