US3814944A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mark sense card reader
Assignee: Monroe Systems for Business Inc
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Filing: 1973-05-24
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Granted: 1974-06-04
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Expires: 1993-05-24
Abstract
Abstract In a circuit arrangement for responding to the presence or absence of a plurality of marks on a card, a means is provided for enabling each of a plurality of mark-sensing circuits to respond to the percentage change in the light reflected from the card, rather than to absolute light level changes, whereby the range of responses of the individual circuits is narrowed considerably and therefore the threshold which must be exceeded for the following detection circuits to respond, may be easily established.
Inventors
- 👤 J Berger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 05:37
CPC Classifications
G; G06; G06K; G06K7/00; G06K7/10; G06K7/10544; G06K7/10821; G06K7/10851
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
98 words
A circuit for reading the presence or absence of a mark on a card, the improvement comprising: phototransistor means positioned to receive and respond to light relfected from said card, said phototransistor means having an emitter and a collector, a bias source connected to said emitter, diode load means connected to said photoresponsive means to make its output vary logarithmically with its input, an operating potential source, means connecting said diode load means between said collector and said operating potential source, and threshold means for geneRating an output signal when said photoresponsive means output exceeds a predetermined threshold.
Claim 2
Dependent Claim
98 words
A circuit for reading the presence or absence of a mark on a card, the improvement comprising: phototransistor means positioned to receive and respond to light relfected from said card, said phototransistor means having an emitter and a collector, a bias source connected to said emitter, diode load means connected to said photoresponsive means to make its output vary logarithmically with its input, an operating potential source, means connecting said diode load means between said collector and said operating potential source, and threshold means for geneRating an output signal when said photoresponsive means output exceeds a predetermined threshold.
Claim 3
Dependent Claim
37 words
A circuit as recited in claim 1 wherein said threshold means includes an operational amplifier, and means to connect said phototransistor collector to said operational amplifier to drive said operational amplifier responsive to output from said phototransistor.
Claim 4
Dependent Claim
18 words
A circuit as recited in claim 1 wherein said load means is a transistor connected as a diode.
Claim 5
Dependent Claim
26 words
A circuit as recited in claim 3 wherein said transistor has base emitter and collector electrodes, and said base electrode is connected to said collector electrode.
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) | 1977-06-03 | 1977-12-03 | 1978-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-03 | 1981-12-03 | 1982-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-03 | 1985-12-03 | 1986-06-04 | $7700.00 | Window Closed / Lapsed |