US 6,209,789 B1Granted

Optical filtering system for a laser bar code scanner having narrow band-pass characteristics employing spatially separated filtering elements including a scanner window

AssigneeMetrologic Instruments, Inc.

InventorsThomas Amundsen, Robert Blake, George Rockstein, David M. Wilz, Sr., Carl H. Knowles

Life of this patent

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Abstract

A novel optical filtering system for a laser bar code scanner having narrow band-pass characteristics is disclosed. The optical filtering system has two different optical filtering elements which are disposed in a scanner housing in a spatially separate relationship. One of the optical filtering elements is positioned inside of the scanner housing in front of and close to the light detection element. The other optical filtering element is positioned in the light transmission aperture of the scanner housing and forms the scanning window. The optical filtering characteristics of the scanning window obscure the internal components of the scanner from plain view making the scanner appear more aesthetically pleasing. Together the optical filtering element cooperate to form a narrow-band pass filter to provide for better light collection and scanning.

Claims13

Dependent claims

A laser symbol scanning system, comprising:

a housing having a light transmission aperture through which light can enter and exit said housing;
laser beam source in said housing for producing a laser beam characterized by a predetermined wavelength;
laser beam scanning element in said housing for projecting said laser beam through said aperture and scanning said laser beam across a code symbol on an object located within at least a portion of a scan field defined external to said housing;
light collection element for collecting laser light reflected off said code symbol and pas sing through said aperture;
laser light detection element in said housing disposed in said laser light path, for detecting the intensity of laser light reflected off said code symbol and collected by said light collection element;
a laser beam directing element mounted to the surface of said light collection element for directing the laser beam produced by said laser beam production element to said laser beam scanning mechanism;
and
a pair of optical filter elements in said housing, spatially separated from each other, each optical filter element having wavelength-selective filtering characteristics, said pair of optical filter elements cooperating so as to form a band-pass optical filtering system having a narrow wavelength bandwidth positioned about said predetermined wavelength such light reflected off said code symbol having wavelengths only within said narrow wavelength bandwidth reach said laser light detection element and wherein one of said pair of optical filtering elements is disposed in said light transmission aperture and functions as a scanning window in said housing.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/436,742Filed 9 Nov 1999 · continuation
Priority: 17 Sep 1991
Granted: 3 Apr 2001
Term ends: Not estimatedThe source records don’t support an estimate.

Classification22 codes

G06K 7/10891
Constructional details of hand-held scanners: the scanner to be worn on a finger or on a wrist
G02B 26/106
Scanning systems: having diffraction gratings as scanning elements, e.g. holographic scanners
G06K 7/10564
Moving beam scanning: light sources
G06K 7/10594
Moving beam scanning: beam path

Family

Application07/761,123Parent of this continuation · filed 17 Sep 1991
Application08/293,491Parent of this continuation-in-part · filed 19 Aug 1994
Application08/439,224Parent of this continuation · filed 11 May 1995
Application08/850,295Parent of this continuation · filed 5 May 1997
Application09/258,005Parent of this continuation · filed 26 Feb 1999
US 5,627,359 AParent of this continuation
Application08/439,224Parent of this continuation-in-part
Application08/293,491Parent of this continuation
US 5,340,971 AParent of this continuation
US 6,029,894 ARelated patent
US 6,209,789 B1This patent

From the US filing history. Foreign family members aren’t listed.