US4809044A
Expired / Lapsed
US
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Thin film overvoltage protection devices
Assignee: Energy Conversion Devices Inc
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Filing: 1986-11-26
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Granted: 1989-02-28
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Expires: 2006-11-26
Abstract
Abstract Solid-state overvoltage protection devices, preferably formed of deposited thin film, chalcogenide, threshold switching materials, typically include at least one elongated current conduction path through an elongated cross-sectional area of the threshold switching material. The cross-sectional area is formed with a length far exceeding the effective width thereof for distributing the transient current produced by overvoltage conditions over a relatively large area. In this manner, the concentration of localized heating effects can be avoided.
Inventors
- 👤 Roger W. Pryor
- 👤 Napoleon P. Formigoni
- 👤 Stanford R. Ovshinsky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:45
CPC Classifications
H; H02; H02H; H02H9/00; H02H9/04; H02H9/044; H10; H10B; H10B63/00; H10B63/80; H10N; H10N70/00; H10N70/011; H10N70/061; H10N70/063; H10N70/20; H10N70/801; H10N70/821; H10N70/823; H10N70/826; H10N70/841; H10N70/881; H10N70/882; H10N70/8828
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
156 words
A solid-state overvoltage protection apparatus of the type having a plurality of spaced electrodes and a body of threshold switching material disposed therebetween, said body having a high electrical resistance to provide a blocking condition for substantially blocking current therethrough at operating voltages below a first nominal voltage level and a lower electrical resistance at overvoltages above said nominal voltage level to provide a conducting condition for conducting current therethrough, the improvement comprising in combination: means for providing an elongated current conduction path of substantially uniform distance between said electrodes through said body confined to an elongated cross-sectional area of said body transverse to the direction of current flow, said cross-sectional area having an effective length along the major dimension of said area which is at least about ten times greater than the maximum effective width of said area, whereby relatively large currents associated with overvoltages which may flow therethrough are distributable over said elongated area.
Claim 2
Dependent Claim
156 words
A solid-state overvoltage protection apparatus of the type having a plurality of spaced electrodes and a body of threshold switching material disposed therebetween, said body having a high electrical resistance to provide a blocking condition for substantially blocking current therethrough at operating voltages below a first nominal voltage level and a lower electrical resistance at overvoltages above said nominal voltage level to provide a conducting condition for conducting current therethrough, the improvement comprising in combination: means for providing an elongated current conduction path of substantially uniform distance between said electrodes through said body confined to an elongated cross-sectional area of said body transverse to the direction of current flow, said cross-sectional area having an effective length along the major dimension of said area which is at least about ten times greater than the maximum effective width of said area, whereby relatively large currents associated with overvoltages which may flow therethrough are distributable over said elongated area.
Claim 3
Dependent Claim
72 words
An apparatus as in claim 1 wherein said plurality of electrodes each has an elongated surface portion adjacent to and in intimate electrical contact with said body, wherein one of said elongated surface portions is physically spaced equidistantly along its length from and operatively disposed with respect to another of said elongated surface portions, thereby providing said elongated current conduction path of substantially uniform distance between said two associated elongated surface portions.
Claim 4
Dependent Claim
16 words
An apparatus as in claim 2 wherein said two associated elongated surface portions are generally non-coplanar.
Claim 5
Dependent Claim
19 words
An apparatus as in claim 1 further including a highly thermally conductive substrate disposed below said threshold switching material.
Claim 6
Dependent Claim
25 words
An apparatus as in claim 1 wherein said substrate has an insulating surface, thereby substantially preventing current flow between said electrode layers and said substrate.
Claim 7
Dependent Claim
15 words
An apparatus as in claim 4 wherein said substrate is formed from a conductive metal.
Claim 8
Dependent Claim
29 words
An apparatus as in claim 3 wherein said substrate is substantially formed from an insulating material selected from the group consisting of deposited diamond, quartz, sapphire, and single-crystal-semiconductor material.
Claim 9
Dependent Claim
17 words
An apparatus as in claim 1 wherein said threshold switching material is a substantially amorphous semiconductor material.
Claim 10
Dependent Claim
17 words
An apparatus as in claim 8 wherein said amorphous semiconductor material includes at least one chalcogenide element.
Claim 11
Dependent Claim
73 words
An apparatus as in claim 1 wherein said threshold switching material has a threshold voltage value substantially equal to said first voltage level, and wherein said high electrical resistance in response to a voltage substantially above said threshold voltage value very rapidly decreases in at least one portion of said path to said lower electrical resistance which is orders of a magnitude lower than said high electrical resistance to provide said conducting condition.
Claim 12
Dependent Claim
30 words
An apparatus as in claim 1 wherein said plurality of electrodes each include a film of electrically conductive, non-single-crystal, phase-stable, non-switching carbon material in intimate electrical contact with said body.
Claim 13
Dependent Claim
16 words
An apparatus as in claim 1 wherein said electrodes each include a thin film refractory material.
Claim 14
Dependent Claim
18 words
An apparatus as in claim 12 wherein said refractory material is in direct contact with threshold switching material.
Claim 15
Dependent Claim
24 words
An apparatus as in claim 1 wherein said threshold switching material and said plurality of electrodes are formed from vacuum deposited thin film materials.
Claim 16
Dependent Claim
49 words
An apparatus as in claim 14 wherein said thin film materials are arranged in layers stacked one on top of the other such that when said current conduction path is formed in said apparatus between said plurality of electrodes said path extends substantially vertically through said threshold switching material.
Claim 17
Dependent Claim
49 words
An apparatus as in claim 14 wherein said electrodes are spaced substantially horizontally apart from one another, and that at least a portion of said threshold switching material extends generally between said layers such that when said current conduction path is formed, it extends substantially horizontally through said material.
Claim 18
Dependent Claim
76 words
An apparatus as in claim 14 wherein one of said electrodes includes a non-insulated part; a first part of another of said electrodes is disposed above and horizontally displaced with respect to the nearest non-insulated part of said one of said electrodes and said threshold switching material is disposed therebetween such that when said current conduction path forms in said apparatus, it extends substantially diagonally through said threshold switching material between said parts of said layers.
Claim 19
Dependent Claim
26 words
An apparatus as in claim 14 wherein at least one of said electrodes and said threshold switching material have been patterned to form a mesa structure.
Claim 20
Dependent Claim
92 words
An apparatus as in claim 1, further comprising: a layer of insulating material having an elongated opening therein in which at least a portion of said threshold switching material extends, and wherein one of said electrodes is disposed substantially in said opening, and another of said electrodes is disposed above said portion of said threshold switching material in said opening, such that when said current conduction path is formed in said apparatus, it extends substantially vertically between said electrode portions through said portion of said threshold switching material disposed in said opening.
Claim 21
Dependent Claim
24 words
An apparatus as in claim 19 wherein said opening defines said maximum effective width and limits said width to less than about five microns.
Claim 22
Dependent Claim
14 words
An apparatus as in claim 1 wherein said elongated current conduction path is serpentine.
Claim 23
Dependent Claim
31 words
An apparatus as in claim 1 wherein at least one of said electrodes is patterned to have a plurality of electrically interconnected sections spaced apart from one another at predetermined angles.
Claim 24
Dependent Claim
42 words
An apparatus as in claim 22 wherein said one patterned electrode includes at least three leg sections interconnected at a common central node section with each such leg section extending outwardly therefrom in a direction different from the other two leg sections.
Claim 25
Dependent Claim
26 words
An apparatus as in claim 23 wherein said patterned layer includes a plurality of common node sections interconnected by at least one of said leg sections.
Claim 26
Dependent Claim
47 words
An apparatus as in claim 24 having at least four common node sections, with each such common node sections being electrically and physically interconnected to two leg sections which each lead to another distinct common node section, thereby Providing redundant electrical paths to each common node sections.
Claim 27
Dependent Claim
76 words
An apparatus as in claim 22 wherein said plurality of leg sections each is associated with its own elongated current conduction path through said body of threshold switching material which is confined to a distinct elongated cross-sectional area of said body thereunderneath transverse to the direction of current flow therethrough, each of said cross-sectional areas having an effective length along its major dimension which is at least about ten times greater than its maximum effective width.
References Cited (Backward Citations)
US4433342A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-28 | 1992-08-29 | 1993-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-28 | 1996-08-29 | 1997-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-28 | 2000-08-29 | 2001-02-28 | $7700.00 | Window Closed / Lapsed |