US3758193A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Infrared-transmissive, visible-light-absorptive retro-reflectors
Assignee: 3M Co
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Filing: 1971-07-02
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Granted: 1973-09-11
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Expires: 1991-07-02
Abstract
Abstract Retro-reflectors that incorporate, between the outer surface of the reflector and a reflective surface within the reflector, a thin layer of a material that transmits infrared radiation and substantially absorbs visible light. The layer comprises discrete, water-insoluble, organic, infrared-transmissive, visible-light-absorptive pigment particles dispersed in a matrix film having an index of refraction substantially the same as the index of refraction of the pigment particles and not substantially greater than the index of refraction of any material between the thin layer and said reflective surface.
Inventors
- 👤 Tung C Fang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:04
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/12; G02B5/126; G02B5/128
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
17 words
A reflector of claim 1 in which the thin layer forms said exterior surface of the reflector.
Claim 2
Dependent Claim
21 words
A reflector of claim 1 in which the thin layer is separated from said exterior surface by another layer of material.
Claim 3
Dependent Claim
21 words
A reflector of claim 3 in which a monolayer of spherical glass beads is disposed between said exterior and reflective surfaces.
Claim 4
Dependent Claim
143 words
Infrared-transmissive, visible-light-absorptive retro-reflective sheeting comprising 1) a base retro-reflective sheeting that incorporates a dense monolayer of visibly transparent retro-reflective spherical glass beads covered with a visibly transparent material that provides a flat exterior surface of the sheeting through which radiation is received for reflection, and 2) a layer between 0.1 and 10 mils in thickness adhered over said flat exterior surface comprising a matrix film and solid discrete pigment partiCles of at least one water-insoluble organic infrared-transmissive visible-light-absorptive pigment dispersed in the matrix film at a particle volume concentration between 0.5 and 20 percent, the matrix film having an index of refraction that is substantially the same as the index of refraction of the pigment and is not substantially greater than the index of refraction of said visibly transparent material, and the layer having an IR/IR+V discrimination ratio of at least 75 percent.
Claim 5
Dependent Claim
19 words
Retro-reflective sheeting of claim 5 in which the organic pigment includes Lithosol Fast Scarlet, Benzedine Yellow, and Heliogen Blue.
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) | 1976-09-10 | 1977-03-12 | 1977-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-10 | 1981-03-12 | 1981-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-10 | 1985-03-12 | 1985-09-11 | $7700.00 | Window Closed / Lapsed |