Patent US5360235A successfully refreshed from Google Patents.
US5360235A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Secret optical marking
Assignee: United States Department of the Navy
•
Filing: 1969-11-01
•
Granted: 1994-11-01
•
Expires: 1989-11-01
Abstract
Abstract An optical marking system in which objects are coated with materials for purposes of applying secretly coded marks on the objects. The coating materials are transparent in daylight and have the property of absorbing ultraviolet light. When such materials are applied to a portion of the surface of an object which is a good ultraviolet reflector, only the uncoated portion reflects ultraviolet. Thus, the marked object is therefore seen as having the coated portion blocked-out when viewed through a device which filters out all but ultraviolet wavelengths but appears to be unmarked when observed without the viewing device. Similar coding of objects may be achieved by appropriately selected paints, papers and other materials.
Inventors
- 👤 Louis F. Drummeter
- 👤 Gordon L. Stamm
- 👤 Gerald E. Rohl
- 👤 Alfred G. Rockman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 07:42
CPC Classifications
B; B41; B41M; B41M3/00; B41M3/14; B41M3/144
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
70 words
A method identifying objects with coded marks comprising the steps of: affixing a first material to said object for reflecting radiation in a non-visible wavelength band, covering a portion of said first material with a second material which does not reflect radiation in said wavelength band, illuminating both materials with radiation in said wavelength band, and observing the reflected radiation through an optical filter which transmits only said wavelength band.
Claim 2
Independent Claim
70 words
A method identifying objects with coded marks comprising the steps of: affixing a first material to said object for reflecting radiation in a non-visible wavelength band, covering a portion of said first material with a second material which does not reflect radiation in said wavelength band, illuminating both materials with radiation in said wavelength band, and observing the reflected radiation through an optical filter which transmits only said wavelength band.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein said second material is transparent at visible wavelengths.
Claim 4
Dependent Claim
26 words
The method of claim 2 further including the step of applying a continuous coating of a transparent third material over both said first and second materials.
Claim 5
Dependent Claim
24 words
The method recited in claim 1 further comprising: converting the reflected radiation transmitted through said filter from a non-visible image to a visible image.
Claim 6
Dependent Claim
19 words
The method of claim 4 wherein the reflected radiation is converted to a visible image by a photographic process.
Claim 7
Dependent Claim
21 words
The method of claim 4 wherein the reflected radiation is converted to a visible image by an electronic image conversion tube.
Claim 8
Dependent Claim
27 words
The method of claim 4 wherein said first material is a good reflector of ultraviolet radiation and said second material is a poor reflector of ultraviolet radiation.
Claim 9
Dependent Claim
19 words
The method of claim 7 wherein said first material is zinc sulfide and said second material is titanium dioxide.
Claim 10
Dependent Claim
43 words
The method of claim 7 wherein said second material is an ultraviolet absorbing benzophenone and further including the step of applying a continuous coating of a transparent acrylic lacquer, which has been flatted with diatomaceous silica, over both said first and second materials.
References Cited (Backward Citations)
US1385657A
Cited
US2929931A
Cited
US3068010A
Cited
US3048697A
Cited
US3234663A
Cited
US3279826A
Cited
US3535022A
Cited
US3473864A
Cited
US3455577A
Cited
US3640009A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-10-31 | 1998-05-02 | 1998-11-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-10-31 | 2002-05-02 | 2002-11-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-10-31 | 2006-05-02 | 2006-11-01 | $7700.00 | Window Closed / Lapsed |