US4384761A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ferrofluid optical switches
Assignee: International Business Machines Corp
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Filing: 1980-06-30
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Granted: 1983-05-24
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Expires: 2000-06-30
Abstract
Abstract A controllable magnetic field influences the position or shape or density distribution of a ferrofluid so that the ferrofluid causes or prevents the coupling of light between optical paths either by physically causing movement of a waveguide (e.g., optical fiber) or by itself physically moving into or out of a coupling region between optical paths.
Inventors
- 👤 Michael J. Brady
- 👤 Lawrence V. Gregor
- 👤 Mark Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:06
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/35; G02B6/3564; G02B6/3568; G02B6/3572; G02B26/00; G02B26/004; G02B6/3502; G02B6/351; G02B6/353; G02B6/3538; G02B6/354; G02B6/3544; G02B6/3548; G02B6/355; G02B6/3552
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
84 words
A light switch, comprising: at least two optical fibers; ferrofluid; means for holding said ferrofluid such that said ferrofluid is capable of assuming at least two different configurations, a first and second of said optical fibers being optically coupled together when said ferrofluid means is in a first of said configurations and not optically coupled together when said ferrofluid means is in a second of said configurations; and controllable magnetic field means for causing said ferrofluid to assume a selected one of said configurations.
Claim 2
Dependent Claim
84 words
A light switch, comprising: at least two optical fibers; ferrofluid; means for holding said ferrofluid such that said ferrofluid is capable of assuming at least two different configurations, a first and second of said optical fibers being optically coupled together when said ferrofluid means is in a first of said configurations and not optically coupled together when said ferrofluid means is in a second of said configurations; and controllable magnetic field means for causing said ferrofluid to assume a selected one of said configurations.
Claim 3
Dependent Claim
34 words
A light switch as defined in claim 1 and comprising at least three optical fibers, said first optical fiber being coupled to a third optical fiber when said ferrofluid is in said second configuration.
Claim 4
Dependent Claim
114 words
A light switch as defined in claim 1 wherein said at least two optical fibers comprise at least four optical fibers, said ferrofluid being capable of being brought into at least four different configurations, said first and second optical fibers being coupled together when said ferrofluid is either in said first configuration or in a third of said configurations and not coupled together when said ferrofluid is in either said second configuration or in a fourth of said configurations, a third and fourth optical fibers being coupled together when said ferrofluid is in either said first or second configurations and not coupled together when said ferrofluid is in either said third or fourth configurations.
Claim 5
Dependent Claim
22 words
A light switch as defined in claim 1 wherein said ferrofluid is brought into different configurations by moving ferrofluid to different positions.
Claim 6
Dependent Claim
23 words
A light switch as defined in claim 4 wherein said ferrofluid is moved by a magnetic field generated by said magnetic field means.
Claim 7
Dependent Claim
26 words
A light switch as defined in claim 1 wherein said ferrofluid is brought into different configurations by changing the distribution of magnetic particles within said ferrofluid.
Claim 8
Dependent Claim
27 words
A light switch as defined in claim 6 wherein said ferrofluid does not substantially change position when the distribution of magnetic particles within said ferrofluid is changed.
Claim 9
Dependent Claim
29 words
A light switch as defined in claim 6 wherein the distribution of magnetic particles within said ferrofluid is changed by a magnetic field generated by said magnetic field means.
Claim 10
Dependent Claim
27 words
A light switch as defined in claim 6 wherein said changing of the distribution of magnetic particles within said ferrofluid changes the density distribution of said ferrofluid.
Claim 11
Dependent Claim
42 words
A light switch as defined in claim 9 wherein said changing of the density distribution of said ferrofluid changes the distribution of buoyancy forces of said ferrofluid upon a movable member in contact with said ferrofluid, thus causing movement of said member.
Claim 12
Dependent Claim
26 words
A light switch as defined in claim 10 wherein said movable member comprises said first optical fiber and said first optical fiber is cantilevered for movement.
Claim 13
Dependent Claim
49 words
A light switch as defined in claim 11 wherein said cantilevered first optical fiber may be controllably brought by said ferrofluid into a predetermined position with respect to said second optical fiber, said predetermined position corresponding to either an optical coupling or uncoupling of said first and second fibers.
Claim 14
Dependent Claim
31 words
A light switch as defined in claim 12 wherein said cantilevered first optical fiber tends to be brought away from said predetermined position by elastic deformation forces of said cantilevered fiber.
Claim 15
Dependent Claim
81 words
A light switch as defined in claim 1 wherein said first and second optical fibers are in spaced alignment with each other, so that light will travel from one of said optical fibers through a space between said optical fibers and into the other of said optical fibers when said space contains a medium transparent to the light, said first configuration corresponding to said space containing a transparent medium and said second configuration corresponding to said space containing an opaque ferrofluid.
Claim 16
Dependent Claim
21 words
A light switch as defined in claim 14 wherein said opaque ferrofluid is moved into said space by a magnetic field.
Claim 17
Dependent Claim
22 words
A light switch as defined in claim 14 wherein said opaque ferrofluid is moved out of said space by a magnetic field.
Claim 18
Dependent Claim
46 words
A light switch as defined in claim 14 wherein said space corresponds to a region within a tube, said tube containing both an opaque ferrofluid and a transparent fluid, the position of said ferrofluid being controlled by a magnetic field generated by said magnetic field means.
Claim 19
Dependent Claim
36 words
A light switch as defined in claim 1 wherein at least one of said optical fibers further comprises a focusing element for directing light from said one optical fiber to another one of said optical fibers.
Claim 20
Dependent Claim
20 words
A light switch as defined in claim 1 wherein said controllable magnetic field means comprises at least one electromagnet element.
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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) | 1986-05-23 | 1986-11-22 | 1987-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-23 | 1990-11-22 | 1991-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-23 | 1994-11-22 | 1995-05-24 | $7700.00 | Window Closed / Lapsed |