US4013893A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical bar code scanning device
Assignee: Welch Allyn Inc
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Filing: 1975-08-07
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Granted: 1977-03-22
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Expires: 1995-08-07
Abstract
Abstract An optical bar code scanning device for high data density bar code reading. The device utilizes a two channel arrangement for directing light reflected from the bar code being read onto two photodetectors in predetermined proportionate amounts. With a two channel system, it is possible to detect a bar edge independent of print contrast variations, resolution modulation or change of illumination by comparing the optical signal of one channel with the optical signal of the other. The bar edge is represented by the crossover point of the normalized outputs of the two channels.
Inventors
- 👤 Urs W. Hertig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 11:55
CPC Classifications
G; G06; G06K; G06K7/00; G06K7/10; G06K7/10544; G06K7/10821; G06K7/10881
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
129 words
In an optical bar code scanning device for high data density bar code reading, the bar code comprising a plurality of bar code elements: means for illuminating the bar code to be read so that light is reflected therefrom, a pair of photodetectors, means for gathering the reflected light so that it falls on the photodetectors, said photodetectors being arranged in the device so that one of them can receive no more reflected light than would be received from a code bar that is twice the width of the smallest bar code element, the other of said photodetectors being arranged so that it receives less reflected light by a predetermined amount than is received by said first mentioned photodetector, and means for comparing the outputs of the two photodetectors.
Claim 2
Dependent Claim
129 words
In an optical bar code scanning device for high data density bar code reading, the bar code comprising a plurality of bar code elements: means for illuminating the bar code to be read so that light is reflected therefrom, a pair of photodetectors, means for gathering the reflected light so that it falls on the photodetectors, said photodetectors being arranged in the device so that one of them can receive no more reflected light than would be received from a code bar that is twice the width of the smallest bar code element, the other of said photodetectors being arranged so that it receives less reflected light by a predetermined amount than is received by said first mentioned photodetector, and means for comparing the outputs of the two photodetectors.
Claim 3
Dependent Claim
35 words
A bar code scanning device as defined in claim 1 wherein said other photodetector is arranged so that it can receive no more reflected light than would be received from the smallest bar code element.
Claim 4
Dependent Claim
18 words
A bar code scanning device as defined in claim 1 wherein said pair of photodetectors are concentrically arranged.
Claim 5
Dependent Claim
69 words
A bar code scanning device as defined in claim 1 wherein said pair of photodetectors are arranged to coact with two bundles of optical fibers, the bundles being concentrically arranged at one end thereof to receive the reflected light and being spaced apart at their other ends, said other ends respectively terminating in adjacent confronting relation to the photodetectors to direct a portion of the reflected light at each.
Claim 6
Dependent Claim
61 words
A bar code scanning device as defined in claim 1 together with beam splitting means to divide the reflected light into two paths, the pair of photodetectors being respectively positioned in said two light paths, and aperture means in each light path between the beam splitting means and photodetector to control the amount of light that is received by the latter.
Claim 7
Dependent Claim
147 words
In an optical bar code scanning device for reading bar codes of high data density, the bar code comprising a plurality of print contrasting code bar elements: a housing, means in the housing for illuminating the bar code to be read so that light is reflected therefrom, a pair of photodetectors in the housing, optical means in the housing for gathering the reflected light so that it falls on the photodetectors, said photodetectors being arranged in the device so that one of them can receive no more reflected light than would be received from the smallest bar code element, the other of said photodetectors being arranged in the device so that it can receive no more reflected light than would be received from a code bar that is twice the width of the smallest bar code element, and comparator means for comparing the outputs of the photodetectors.
Claim 8
Dependent Claim
147 words
In an optical bar code scanning device for reading bar codes of high data density, the bar code comprising a plurality of print contrasting code bar elements: a housing, means in the housing for illuminating the bar code to be read so that light is reflected therefrom, a pair of photodetectors in the housing, optical means in the housing for gathering the reflected light so that it falls on the photodetectors, said photodetectors being arranged in the device so that one of them can receive no more reflected light than would be received from the smallest bar code element, the other of said photodetectors being arranged in the device so that it can receive no more reflected light than would be received from a code bar that is twice the width of the smallest bar code element, and comparator means for comparing the outputs of the photodetectors.
Claim 9
Dependent Claim
18 words
A bar code scanning device as defined in claim 6 wherein said pair of photodetectors are concentrically arranged.
Claim 10
Dependent Claim
69 words
A bar code scanning device as defined in claim 6 wherein said pair of photodetectors are arranged to coact with two bundles of optical fibers, the bundles being concentrically arranged at one end thereof to receive the reflected light and being spaced apart at their other ends, said other ends respectively terminating in adjacent confronting relation to the photodetectors to direct a portion of the reflected light at each.
Claim 11
Dependent Claim
61 words
A bar code scanning device as defined in claim 6 together with beam splitting means to divide the reflected light into two paths, the pair of photodetectors being respectively positioned in said two light paths, and aperture means in each light path between the beam splitting means and photodetector to control the amount of light that is received by the latter.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-03-21 | 1980-09-20 | 1981-03-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-21 | 1984-09-20 | 1985-03-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-21 | 1988-09-20 | 1989-03-22 | $7700.00 | Window Closed / Lapsed |