EP0249713A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Optical scanner for reading bar codes detected within a large depth of field
Assignee: International Business Machines Corp
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Filing: 1987-04-16
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Granted: —
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Expires: 2007-04-16
Abstract
Abstract Optical scanner for reading bar codes scanned by focussed scan lines having different focal lengths where at least one of the scan lines is small relative to irregularities of the surface on which the label (10) appears. The scan lines are generated using a holographic disk (18) so as to have a predetermined focal length and focal zone. The focal zone of each generated scan line overlaps the focal point of at least one adjacent scan line. Any bar code label (10) which might be scanned by a beam so small that it would be degraded by surface scatter noise is also scanned by a slightly larger beam. The slightly larger beam "averages out" the surface scattering noise to produce a smoother or cleaner return signal.
Inventors
- 👤 Leroy David Dickson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 23:26
CPC Classifications
G; G06; G06K; G06K7/00; G06K7/10; G06K7/10544; G06K7/10821; G06K7/10861; G06K7/10871; G02; G02B; G02B26/00; G02B26/08; G02B26/10; G02B26/106; G06K2207/00; G06K2207/1013
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
108 words
An optical scanner for reading bar code labels at different distances from the scanner, said scanner including a coherent light beam source (16) and a beam deflector (18) capable of deflecting and focussing the light beam to produce a set of scan lines (SL1 to SL6) , each of the scan lines having a focal zone (FZ1 to FZ6) which overlaps the focal point of at least one other of said scan lines, said beam deflector producing a scan spot in the focal zone (FZ1) closest to the deflector which is relatively small in comparison to irregularities of the surface on which the bar code label (10) appears.
Claim 2
Dependent Claim
108 words
An optical scanner for reading bar code labels at different distances from the scanner, said scanner including a coherent light beam source (16) and a beam deflector (18) capable of deflecting and focussing the light beam to produce a set of scan lines (SL1 to SL6) , each of the scan lines having a focal zone (FZ1 to FZ6) which overlaps the focal point of at least one other of said scan lines, said beam deflector producing a scan spot in the focal zone (FZ1) closest to the deflector which is relatively small in comparison to irregularities of the surface on which the bar code label (10) appears.
Claim 3
Dependent Claim
58 words
The optical scanner as defined in claim 1 wherein the focal zone of a particular scan line (SL1 to SL6) is defined as the region within which the scan spot is sufficiently small to be able to discriminate between the bars and spaces of the smallest allowable bar code label (10) intended to be read by the scanner.
Claim 4
Dependent Claim
28 words
The optical scanner as defined in claim 2 wherein successive scan lines (SL1 to SL6) produced by said beam deflector have successively longer focal lengths (FL1 to FL6).
Claim 5
Dependent Claim
46 words
The optical scanner as defined in either of claims 2 or 3 wherein said beam deflector (18) comprises a rotating disk having a plurality of adjacent holographic facets, each of said facets being capable of focussing the light beam at a predetermined distance from the facet.
Claim 6
Independent Claim
137 words
A method for reading bar coded labels with an optical scanner of the type including a coherent light beam source (16) and a beam deflector (18) capable of deflecting and focussing the light beam to produce a set of scan lines (SL1 to SL6), each focussed at a different predetermined focal length, said method comprising the step of scanning the label (10) with at least two different scan lines while the label is within the focal zone (FZ1 to FZ6) of both of said scan lines, the scan spot in at least one of the scan lines generated by the deflector being relatively large in comparison to irregularities of the surface on which the label appears whereby the reading problems associated with optical noise resulting from scattering from the surface on which the label appears are minimized.
Claim 7
Independent Claim
137 words
A method for reading bar coded labels with an optical scanner of the type including a coherent light beam source (16) and a beam deflector (18) capable of deflecting and focussing the light beam to produce a set of scan lines (SL1 to SL6), each focussed at a different predetermined focal length, said method comprising the step of scanning the label (10) with at least two different scan lines while the label is within the focal zone (FZ1 to FZ6) of both of said scan lines, the scan spot in at least one of the scan lines generated by the deflector being relatively large in comparison to irregularities of the surface on which the label appears whereby the reading problems associated with optical noise resulting from scattering from the surface on which the label appears are minimized.
Claim 8
Dependent Claim
31 words
The method as defined in claim 5 wherein said scanning step further comprising the step of scanning the label (10) with scan lines (SL1 to SL6) having progressively longer focal lengths.
References Cited (Backward Citations)
No citation records indexed.
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