US4467278A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microwave oven leak detector
Assignee: Individual
•
Filing: 1981-08-27
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Granted: 1984-08-21
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Expires: 2001-08-27
Abstract
Abstract A liquid crystal film pack for detecting leakage from a microwave oven by passing the moist film pack adjacent the joints and seams of the oven to produce a color change in the liquid crystal material in response to a microwave radiation leak.
Inventors
- 👤 Emery K. Toth
- 👤 Lawrence E. Egbert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:35
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/64; H05B6/6432; G; G01; G01R; G01R13/00; G01R13/40; G01R13/401; G01R13/403
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
55 words
Means for detecting microwave radiation leakage from a microwave oven, comprising: a heat responsive liquid crystal material adapted to produce a color change in response to an increase in temperature of the material; and first means moistened for contacting the liquid crystal material with a liquid to generate heat in the presence of microwave energy.
Claim 2
Dependent Claim
55 words
Means for detecting microwave radiation leakage from a microwave oven, comprising: a heat responsive liquid crystal material adapted to produce a color change in response to an increase in temperature of the material; and first means moistened for contacting the liquid crystal material with a liquid to generate heat in the presence of microwave energy.
Claim 3
Dependent Claim
50 words
Means for detecting leakage from microwave oven as defined in claim 1, in which the liquid crystal material comprises a film of microencapsulated temperature-responsive liquid crystal material having a first color at a first temperature and adapted to change to a second color in response to an increased, second temperature.
Claim 4
Dependent Claim
34 words
Means for detecting leakage from a microwave oven as defined in claim 1, in which the second temperature is about 82° F. and the first temperature is a room temperature less than 80° F.
Claim 5
Dependent Claim
27 words
Means for detecting leakage from microwave oven as defined in claim 1, in which said means comprises a section of blotting paper engaging said liquid crystal material.
Claim 6
Independent Claim
65 words
A method for visually detecting leakage in a microwave oven, comprising: moistening a moisture-absorbent material in contact with a temperature-responsive liquid crystal material of a first color; passing the moist moisture absorbent material adjacent the microwave oven; and observing the liquid crystal material change from a first color to a second color in response to heat generated in the material by exposure to microwave radiation.
Claim 7
Independent Claim
65 words
A method for visually detecting leakage in a microwave oven, comprising: moistening a moisture-absorbent material in contact with a temperature-responsive liquid crystal material of a first color; passing the moist moisture absorbent material adjacent the microwave oven; and observing the liquid crystal material change from a first color to a second color in response to heat generated in the material by exposure to microwave radiation.
Claim 8
Dependent Claim
18 words
A method as defined in claim 5, in which the material comprises a microencapsulated temperature-responsive liquid crystal material.
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) | 1987-08-21 | 1988-02-20 | 1988-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-21 | 1992-02-20 | 1992-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-21 | 1996-02-20 | 1996-08-21 | $7700.00 | Window Closed / Lapsed |