US5252441A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transparent magnetic recording layers and photographic elements containing the same
Assignee: Eastman Kodak Co
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Filing: 1990-11-06
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Granted: 1993-10-12
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Expires: 2010-11-06
Abstract
Abstract A photographic element including a light-sensitive layer and a transparent magnetic layer wherein the magnetic particles in the transparent binder are cobalt surface treated gamma iron oxide (Fe 2 O 3 ) having a specific area of at least 30 m 2 /g, the particles being coated with from about 10 to about 50% by weight of a material having a refractive index less than that of the binder, the particles having a powder coercivity greater than about 450 Oe.
Inventors
- 👤 Robert O. James
- 👤 Sidney J. Bertucci
- 👤 George L. Oltean
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:02
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; G11B5/70652; G11B5/70668; G11B5/70673; G03; G03C; G03C5/00; G03C5/12; G03C5/14; G11B5/633
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
92 words
A transparent magnetic film comprising magnetic particles in a transparent binder, said magnetic particles being cobalt surface treated gamma Fe 2 O 3 having a specific surface area of at least 30 m 2 /g and exhibiting powder coercivities greater than 450 Oe, said magnetic particles being coated with from about 10 to about 50 percent by weight of a material having a refractive index less than that of said binder, the concentration of the coated magnetic particles in the film being from about 1 to about 10 mg/1000 cm 2 .
Claim 2
Dependent Claim
92 words
A transparent magnetic film comprising magnetic particles in a transparent binder, said magnetic particles being cobalt surface treated gamma Fe 2 O 3 having a specific surface area of at least 30 m 2 /g and exhibiting powder coercivities greater than 450 Oe, said magnetic particles being coated with from about 10 to about 50 percent by weight of a material having a refractive index less than that of said binder, the concentration of the coated magnetic particles in the film being from about 1 to about 10 mg/1000 cm 2 .
Claim 3
Dependent Claim
27 words
A transparent magnetic film of claim 1 wherein the magnetic particles are present in a concentration of from about 2 to about 8 mg/1000 cm 2 .
Claim 4
Dependent Claim
29 words
The transparent magnetic film of claim 1 wherein the specific surface area of the magnetic cobalt treated gamma Fe 2 O 3 is at least 40 m 2 /gm.
Claim 5
Dependent Claim
24 words
The transparent magnetic film of claim 1 wherein the powder coercivity of the magnetic particles is from about 650 Oe to about 850 Oe.
Claim 6
Dependent Claim
26 words
The transparent magnetic film of claim 1 wherein the coating on the magnetic particles makes up 20 to 45 percent by weight of the coated particles.
Claim 7
Dependent Claim
32 words
The transparent magnetic film of claim 1 wherein the coating on the magnetic particles is a material selected from the group consisting of silica, magnesium fluoride, calcium fluoride, and fluorinated hydrocarbon resins.
Claim 8
Dependent Claim
15 words
The transparent magnetic film of claim 6 wherein the coating material is SiO 2 .
Claim 9
Dependent Claim
15 words
The transparent magnetic film of claim 6 wherein the coating material is fluorinated hydrocarbon resin.
Claim 10
Dependent Claim
12 words
The transparent magnetic film of claim 8 wherein the coating is polytetrafluoroethylene.
Claim 11
Dependent Claim
16 words
The transparent magnetic film of claim 1 wherein the coating on the magnetic particles contains voids.
Claim 12
Dependent Claim
26 words
The transparent magnetic film of claim 1 wherein the magnetic particles are present in a concentration of about 4.5 to about 5.5 mg/1000 cm 2 .
Claim 13
Dependent Claim
27 words
The transparent magnetic film of claim 1 wherein the refractive indices of the coating and the binder are less than the refractive index of the magnetic particles.
Claim 14
Dependent Claim
104 words
A photographic element having a light-sensitive layer and a transparent magnetic layer, the transparent magnetic layer comprising magnetic particles in a transparent binder, said magnetic particles being cobalt surface treated gamma Fe 2 O 3 having a specific surface area of at least 30 m 2 /g and exhibiting powder coercivities of at least 550 Oe, said magnetic particles being coated with from about 10 to about 50 percent by weight of a material being a refractive index less than that of said binder, the concentration of the coated magnetic in the layer being from about 1 to about 10 mg/1000 cm 2 .
Claim 15
Dependent Claim
104 words
A photographic element having a light-sensitive layer and a transparent magnetic layer, the transparent magnetic layer comprising magnetic particles in a transparent binder, said magnetic particles being cobalt surface treated gamma Fe 2 O 3 having a specific surface area of at least 30 m 2 /g and exhibiting powder coercivities of at least 550 Oe, said magnetic particles being coated with from about 10 to about 50 percent by weight of a material being a refractive index less than that of said binder, the concentration of the coated magnetic in the layer being from about 1 to about 10 mg/1000 cm 2 .
Claim 16
Dependent Claim
26 words
The photographic element of claim 13 wherein the magnetic particles are present in a concentration of from about 4 to about 8 mg/1000 cm 2 .
Claim 17
Dependent Claim
26 words
The photographic element of claim 13 wherein the magnetic particles are present in a concentration of from about 4.5 to about 5.5 mg/1000 cm 2 .
Claim 18
Dependent Claim
28 words
The photographic element of claim 13 wherein the specific surface area of the magnetic cobalt treated gamma Fe 2 O 3 is at least 40 m 2 /gm.
Claim 19
Dependent Claim
23 words
The photographic element of claim 13 wherein the powder coercivity of the magnetic particles is from about 650 Oe to about 850 Oe.
Claim 20
Dependent Claim
25 words
The photographic element of claim 13 wherein the coating on the magnetic particles makes up 20 to 45 percent by weight of the coated particles.
Claim 21
Dependent Claim
31 words
The photographic element of claim 13 wherein the coating on the magnetic particles is a material selected from the group consisting of silica, magnesium fluoride, calcium fluoride, and fluorinated hydrocarbon resins.
Claim 22
Dependent Claim
14 words
The photographic element of claim 13 wherein the coating material is SiO 2 .
Claim 23
Dependent Claim
15 words
The photographic element of claim 13 wherein the coating material is a fluorinated hydrocarbon resin.
Claim 24
Dependent Claim
11 words
The photographic element of claim 13 wherein the coating is polytetrafluoroethylene.
Claim 25
Dependent Claim
24 words
The photographic element of claim 13 wherein the light sensitive layer and the transparent magnetic layer are disposed on opposite side of a substrate.
Claim 26
Dependent Claim
15 words
The photographic element of claim 13 wherein the coating or the magnetic particles contains voids.
Claim 27
Dependent Claim
26 words
The photographic element of claim 13 wherein the refractive indices of the coating and the binder are less than the refractive index of the magnetic particles.
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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) | 1996-10-11 | 1997-04-12 | 1997-10-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-10-11 | 2001-04-12 | 2001-10-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-10-11 | 2005-04-12 | 2005-10-12 | $7700.00 | Window Closed / Lapsed |