US4510436A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dielectric measuring systems
Assignee: Southwest Medical Products Inc
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Filing: 1982-07-15
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Granted: 1985-04-09
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Expires: 2002-07-15
Abstract
Abstract A capacitive transducer which comprises a pair of joined-together thin-film capacitors and a fluid-impervious container. The container may be filled with a standard solution of known composition. One of the two thin-film capacitors is immersed in the standard solution inside the container while the other is situated outside the container. The entire transducer may be immersed in a sample, and the capacitance of the outside capacitor, which is dependent on the dielectric constant of the sample, may be compared with that of the inside capacitor after the standard solution has reached thermal equilibrium with the sample.
Inventors
- 👤 Leonard S. Raymond
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:01
CPC Classifications
G; G01; G01R; G01R27/00; G01R27/02; G01R27/26; G01R27/2617; G01R27/2635
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
164 words
A transducer for measuring a property related to the dielectric properties of a sample fluid, said transducer being adapted for at least partial immersion in said sample fluid and comprising in combination: a first capacitive sensor comprising a plurality of interdigitated coplanar electrically conductive metal film electrodes deposited on an electrically insulating substrate; a second capacitive sensor comprising a plurality of intedigitated coplanar electrically conductive metal film electrodes deposited on an electrically insulating substrate; said first and second sensors being mounted so as to be (a) mechanically and electrostatically isolated from one another and (b) in direct thermal communication with one another; and an enclosure surrounding said second capacitive sensor for containing a reference fluid so that said reference fluid is (a) in contact with said second capacitive sensor, (b) in fluid and electrical isolation from said first capacitive sensor and a fluid sample contacted by said first capacitive sensor and (c) in thermal communication with a fluid sample contacting said first capacitive sensor.
Claim 2
Dependent Claim
164 words
A transducer for measuring a property related to the dielectric properties of a sample fluid, said transducer being adapted for at least partial immersion in said sample fluid and comprising in combination: a first capacitive sensor comprising a plurality of interdigitated coplanar electrically conductive metal film electrodes deposited on an electrically insulating substrate; a second capacitive sensor comprising a plurality of intedigitated coplanar electrically conductive metal film electrodes deposited on an electrically insulating substrate; said first and second sensors being mounted so as to be (a) mechanically and electrostatically isolated from one another and (b) in direct thermal communication with one another; and an enclosure surrounding said second capacitive sensor for containing a reference fluid so that said reference fluid is (a) in contact with said second capacitive sensor, (b) in fluid and electrical isolation from said first capacitive sensor and a fluid sample contacted by said first capacitive sensor and (c) in thermal communication with a fluid sample contacting said first capacitive sensor.
Claim 3
Dependent Claim
18 words
A transducer according to claim 1 wherein further said interior portion is substantially filled with said second fluid.
Claim 4
Dependent Claim
28 words
A transducer according to claim 2 wherein said first fluid is an electrolytic solution and said second fluid is a reference solution of known concentration of said electrolyte.
Claim 5
Dependent Claim
16 words
A transducer according to claim 3 wherein said electrolyte is a dilute solution of sulfuric acid.
Claim 6
Dependent Claim
37 words
A transducer according to claims 1 or 2 wherein further said first capacitive sensor and said second capacitive sensor are mounted on a common substrate and said substrate is chosen from a material of high thermal conductivity.
Claim 7
Dependent Claim
12 words
A transducer according to claim 5 wherein said substrate is a lamina.
Claim 8
Dependent Claim
25 words
A transducer according to claim 6 wherein said substrate is a material chosen from the group of materials consisting of sapphire, quartz, glass, and alumina.
Claim 9
Dependent Claim
22 words
A transducer according to claims 1 or 2 wherein said electrically conductive electrodes are fabricated from an electrically conductive thin metallic film.
Claim 10
Dependent Claim
30 words
A transducer according to claim 8 wherein said metallic film is formed from a material chosen from the group of materials including chromium, aluminum, titanium, tantalum, tungsten, platinum, and paladium.
Claim 11
Dependent Claim
24 words
A transducer according to claim 8 wherein said first and second capacitive sensors are formed of similar pluralities of similarly spaced apart parallel electrodes.
Claim 12
Dependent Claim
27 words
A transducer according to claims 1 or 2 wherein further at least one non-reactive impervious dielectric layer is superposed upon at least one of said capacitive sensors.
Claim 13
Dependent Claim
31 words
A transducer according to claim 11 wherein said dielectric layer is formed from a material chosen from the group of materials including silicon nitride, silicon dioxide, silicon oxynitride, and aluminum oxide.
Claim 14
Dependent Claim
18 words
A transducer according to claim 11 wherein said at least one dielectric layer is a pluarility of layers.
Claim 15
Dependent Claim
18 words
A transducer according to claim 13 wherein one of said plurality of dielectric layers is formed of polyimide.
Claim 16
Dependent Claim
18 words
A transducer according to claims 1 or 2 wherein further a secondary non-fluid permeable non-reactive enclosure is provided.
Claim 17
Dependent Claim
62 words
A transducer according to claims 1 or 2 wherein: (a) said first capacitive sensor and said second capacitive sensor are mounted on a common substrate of high thermal conductivity; (b) said electrically conductive electrodes are fabricated from an electrically conductive thin metallic film; and (c) at least one non-reactive impervious dielectric layer is superposed upon at least one of said capacitive sensors.
Claim 18
Dependent Claim
64 words
A transducer according to claim 16 wherein: (a) said substrate is a lamina fabricated from the group of materials including sapphire, quartz, glass, and alumina; (b) said first and second capacitive sensors are formed of similar pluralities of similarly spaced apart parallel electrodes; and (c) said at least one dielectric layer is a plurality of layers, one of said layers being formed of polyimide.
Claim 19
Dependent Claim
30 words
A transducer according to claim 5 wherein said metallic film is formed from a material chosen from the group of materials consisting of chromiun, aluminum, titanium, tungsten, platinum, and paladium.
Claim 20
Dependent Claim
28 words
A transducer according to claim 5 wherein at least one of said capacitive sensors comprises at least one dielectric layer covering the said interdigitated metal film electrodes thereof.
Claim 21
Dependent Claim
32 words
A transducer according to claim 19 wherein said dielectric layer is formed from a material chosen from the group of materials consisting of silicon nitride, silicon dioxide, silicon oxynitride, and aluminum oxide.
Claim 22
Dependent Claim
18 words
A transducer according to claim 19 wherein said at least one dielectric layer is a plurality of layers.
Claim 23
Dependent Claim
18 words
A transducer according to claim 21 wherein one of said plurality of dielectric layers is formed of polyimide.
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) | 1988-04-08 | 1988-10-08 | 1989-04-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-08 | 1992-10-08 | 1993-04-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-08 | 1996-10-08 | 1997-04-09 | $7700.00 | Window Closed / Lapsed |