US4055377A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetically orientable retroreflectorization particles
Assignee: 3M Co
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Filing: 1976-08-03
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Granted: 1977-10-25
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Expires: 1996-08-03
Abstract
Abstract Novel magnetically orientable retroreflectorization particles permit application of highly oriented retroreflective coatings. The retroreflectorization particles individually comprise at least one transparent microsphere, specular reflective means in optical connection with a first portion of said microsphere so as to provide retroreflection of light incident on the opposed portion of the microsphere, and a magnetic layer underlying said specular reflective means and having a magnetic axis parallel to the optical axis on which said first and opposed portions of the microsphere are aligned. When the particles are applied to a substrate in the presence of a magnetic field having flux lines of appropriate polarity perpendicular to the substrate, the particles tend to become aligned in a common direction that retroreflects light incident on the coating.
Inventors
- 👤 Randall L. Erickson
- 👤 Terry R. Bailey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:04
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/12; G02B5/126; G02B5/128; G02F; G02F1/00; G02F1/01; G02F1/09; G02F1/091; G09; G09F; G09F13/00; G09F13/16; H; H01; H01F; H01F10/00; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
127 words
A mass of discrete retroreflectorization particles useful for forming a retroreflective coating on a substrate, the individual particles each comprising at least one transparent microsphere, specular reflective means in optical connection with a first portion of the microsphere so as to provide retroreflection of light incident on the opposed portion of the microsphere, and a magnetic layer underlying the specular reflective means and having a magnetic axis parallel to the optical axis on which said first and opposed portions of the microsphere are aligned, whereby when the particles are coated onto a substrate in the presence of a magnetic field having flux lines of appropriate polarity perpendicular to the substrate, the particles tend to become aligned in a common direction that retroreflects light incident on the coating.
Claim 2
Dependent Claim
127 words
A mass of discrete retroreflectorization particles useful for forming a retroreflective coating on a substrate, the individual particles each comprising at least one transparent microsphere, specular reflective means in optical connection with a first portion of the microsphere so as to provide retroreflection of light incident on the opposed portion of the microsphere, and a magnetic layer underlying the specular reflective means and having a magnetic axis parallel to the optical axis on which said first and opposed portions of the microsphere are aligned, whereby when the particles are coated onto a substrate in the presence of a magnetic field having flux lines of appropriate polarity perpendicular to the substrate, the particles tend to become aligned in a common direction that retroreflects light incident on the coating.
Claim 3
Dependent Claim
33 words
Retroreflectorization particles of claim 1 which individually include from one up to an average of about ten transparent microspheres arranged as a closely packed monolayer and supported in a layer of binder material.
Claim 4
Dependent Claim
23 words
Retroreflectorization particles of claim 2 in which said magnetic layer comprises magnetic pigment dispersed in at least a portion of said binder material.
Claim 5
Dependent Claim
39 words
Retroreflectorization particles of claim 2 in which at least a portion of said binder material softens in the presence of heat to an adhesive state whereby the retroreflectorization particles will adhere to a substrate to which they are applied.
Claim 6
Dependent Claim
19 words
Retroreflectorization particles of claim 1 in which said specular reflective means is a coating applied directly to the microsphere.
Claim 7
Dependent Claim
88 words
Retroreflectorization particles of claim 5 in which said coating comprises a transparent thin layer having a refractive index n 1 , the faces of said transparent layer being in contact with materials of refractive index n 2 and n 3 , both n 2 and n.sub. 3 being at least 0.1 either higher or lower than n 1 , and the transparent layer having an optical thickness corresponding to an odd-numbered multiple of about one-quarter wavelength of light in the wavelength range of about 3800 to 10,000 angstroms.
Claim 8
Dependent Claim
18 words
A coating composition comprising a liquid paint vehicle and retroreflectorization particles of claim 1 dispersed in the vehicle.
Claim 9
Dependent Claim
33 words
A method for reflectorizing a substrate comprising applying retroreflectorization particles of claim 1 to the substrate in the presence of a magnetic field having flux lines of appropriate polarity perpendicular to the substrate.
Claim 10
Dependent Claim
12 words
A method of claim 8 in which the substrate is a fabric.
Claim 11
Dependent Claim
11 words
Fabric carrying a sparse coating of retroreflectorization particles of claim 1.
Claim 12
Dependent Claim
156 words
A mass of discrete retroreflectorization particles useful for forming a retroreflective coating on a substrate, the individual particles each comprising one or more transparent microspheres arranged as a closely packed monolayer, a segment of binder material in which said microspheres are partially embedded, specular reflective means in optical connection with the embedded portion of the microspheres so as to provide retroreflection of light incident on the portion of the microspheres opposite from the embedded portion, and magnetic particles dispersed in said binder material and aligned so as to provide the retroreflectorization particles with a magnetic axis parallel to the optical axis on which said opposite and embedded portions of the microspheres are aligned, whereby when the particles are applied to a substrate in the presence of a magnetic field having flux lines of appropriate polarity perpendicular to the substrate, the particles tend to become aligned in a common direction that retroreflects light incident on the coating.
Claim 13
Dependent Claim
156 words
A mass of discrete retroreflectorization particles useful for forming a retroreflective coating on a substrate, the individual particles each comprising one or more transparent microspheres arranged as a closely packed monolayer, a segment of binder material in which said microspheres are partially embedded, specular reflective means in optical connection with the embedded portion of the microspheres so as to provide retroreflection of light incident on the portion of the microspheres opposite from the embedded portion, and magnetic particles dispersed in said binder material and aligned so as to provide the retroreflectorization particles with a magnetic axis parallel to the optical axis on which said opposite and embedded portions of the microspheres are aligned, whereby when the particles are applied to a substrate in the presence of a magnetic field having flux lines of appropriate polarity perpendicular to the substrate, the particles tend to become aligned in a common direction that retroreflects light incident on the coating.
Claim 14
Dependent Claim
15 words
Retroreflectorization particles of claim 9 which include on the average up to about ten microspheres.
Claim 15
Dependent Claim
29 words
Retroreflectorization particles of claim 11 in which said binder material may at least in part be softened in the presence of heat to adhere the particles to a substrate.
Claim 16
Dependent Claim
19 words
Retroreflectorization particles of claim 11 in which said specular reflective means is a coating applied directly to the microspheres.
Claim 17
Dependent Claim
87 words
Retroreflectorization particles of claim 14 in which said coating comprises a transparent thin layer having a refractive index n 1 , the faces of said transparent layer being in contact with materials of refractive index n 2 and n 3 , both n 2 and n 3 being at least 0.1 either higher or lower than n 1 and the transparent layer having an optical thickness corresponding to an odd-numbered multiple of about one-quarter wavelength of light in the wavelength range of about 3800 to 10,000 angstroms.
Claim 18
Dependent Claim
14 words
Retroreflectorization particles of claim 11 in which said magnetic pigment comprises barium ferrite particles.
Claim 19
Dependent Claim
18 words
A coating composition comprising a liquid paint vehicle and retroreflectorization particles of claim 11 dispersed in the vehicle.
Claim 20
Dependent Claim
33 words
A method for reflectorizing a substrate comprising applying retroreflectorization particles of claim 11 to the substrate in the presence of a magnetic field having flux lines of appropriate polarity perpendicular to the substrate.
Claim 21
Dependent Claim
12 words
A method of claim 18 in which the substrate is a fabric.
Claim 22
Dependent Claim
11 words
Fabric carrying a sparse coating of retroreflectorization particles of claim 11.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-10-24 | 1981-04-25 | 1981-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-24 | 1985-04-25 | 1985-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-24 | 1989-04-25 | 1989-10-25 | $7700.00 | Window Closed / Lapsed |