US5818337A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Masked passive infrared intrusion detection device and method of operation therefore
Assignee: C&K Systems Inc
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Filing: 1997-01-13
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Granted: 1998-10-06
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Expires: 2017-01-13
Abstract
Abstract A passive infrared intrusion detection device uses a dual element pyroelectric detector and a housing for surrounding and containing the dual element pyroelectric detector. The housing has a plurality of Fresnel lens elements for gathering infrared radiation from a "look down" volume of space and for focusing the gathered infrared radiation onto the pyroelectric detector. A mask positioned between the plurality of Fresnel lens elements and the detector partially occludes the gathered infrared radiation from the Fresnel lens elements to one of the elements of the dual element pyroelectric detector creating an imbalance in the signal thereby preventing common mode rejection.
Inventors
- 👤 Fernando Erismann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:40
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/18; G08B13/189; G08B13/19; G08B13/191
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
100 words
A passive infrared intrusion detection device for detecting infrared radiation from a volume of space, said device comprising: a dual element pyroelectric detector; a housing for surrounding and containing said dual element pyroelectric detector; said housing having a plurality of fresnel lens elements for gathering infrared radiation from said volume of space and for focusing said gathered infrared radiation onto said pyroelectric detector; and a mask positioned between said plurality of fresnel lens element and said detector for partially occluding said gathered infrared radiation from said fresnel lens elements to one of said elements of said dual elements pyroelectric detector.
Claim 2
Dependent Claim
100 words
A passive infrared intrusion detection device for detecting infrared radiation from a volume of space, said device comprising: a dual element pyroelectric detector; a housing for surrounding and containing said dual element pyroelectric detector; said housing having a plurality of fresnel lens elements for gathering infrared radiation from said volume of space and for focusing said gathered infrared radiation onto said pyroelectric detector; and a mask positioned between said plurality of fresnel lens element and said detector for partially occluding said gathered infrared radiation from said fresnel lens elements to one of said elements of said dual elements pyroelectric detector.
Claim 3
Dependent Claim
21 words
The device of claim 1 wherein said housing is made of plastic with said plurality of fresnel lens elements molded therein.
Claim 4
Dependent Claim
18 words
The device of claim 1 wherein said plurality of fresnel lens elements are made of high density polyethylene.
Claim 5
Dependent Claim
143 words
A passive infrared intrusion detection device for detecting infrared radiation from a first and a second volume of space, said device comprising: a dual element pyroelectric detector; a housing for surrounding and containing said dual element pyroelectric detector; said housing having a first plurality of fresnel lens elements for gathering infrared radiation from said first volume of space and for focusing said gathered infrared radiation onto said pyroelectric detector; said housing further having a second plurality of fresnel lens elements for gathering infrared radiation from said second volume of space and for focusing said gathered infrared radiation onto said pyroelectric detector; and a mask positioned between said second plurality of fresnel lens elements and said pyroelectric detector for partially occluding said gathered infrared radiation from said second plurality of fresnel lens elements to one of said elements of said dual element pyroelectric detector.
Claim 6
Dependent Claim
143 words
A passive infrared intrusion detection device for detecting infrared radiation from a first and a second volume of space, said device comprising: a dual element pyroelectric detector; a housing for surrounding and containing said dual element pyroelectric detector; said housing having a first plurality of fresnel lens elements for gathering infrared radiation from said first volume of space and for focusing said gathered infrared radiation onto said pyroelectric detector; said housing further having a second plurality of fresnel lens elements for gathering infrared radiation from said second volume of space and for focusing said gathered infrared radiation onto said pyroelectric detector; and a mask positioned between said second plurality of fresnel lens elements and said pyroelectric detector for partially occluding said gathered infrared radiation from said second plurality of fresnel lens elements to one of said elements of said dual element pyroelectric detector.
Claim 7
Dependent Claim
24 words
The device of claim 4 wherein said housing is made of plastic with said first and second plurality of fresnel lens elements molded therein.
Claim 8
Dependent Claim
18 words
The device of claim 4 wherein said plurality of fresnel lens elements are made of high density polyethylene.
Claim 9
Dependent Claim
42 words
The device of claim 4 wherein said first plurality of fresnel lens elements is in said housing in a first plane, said second plurality of fresnel lens elements is in said housing in a second plane, substantially perpendicular to said first plane.
Claim 10
Dependent Claim
22 words
The device of claim 7 wherein said second volume of space is closer to said housing than said first volume of space.
Claim 11
Dependent Claim
24 words
The device of claim 7 wherein said housing is made of plastic with said first and second plurality of fresnel lens elements molded therein.
Claim 12
Dependent Claim
24 words
The device of claim 4 wherein each of said second plurality of fresnel lens elements has a focal length greater than about 20 mm.
Claim 13
Independent Claim
68 words
A method of detecting an intruder in a volume of space, said intruder radiating infrared radiation; said method comprising: gathering said infrared radiation from said volume of space by a plurality of optical elements and focusing said gathered infrared radiation onto a dual element pyroelectric detector; and partially occluding said gathered infrared radiation from said optical elements to one of said elements of said dual element pyroelectric detector.
Claim 14
Independent Claim
68 words
A method of detecting an intruder in a volume of space, said intruder radiating infrared radiation; said method comprising: gathering said infrared radiation from said volume of space by a plurality of optical elements and focusing said gathered infrared radiation onto a dual element pyroelectric detector; and partially occluding said gathered infrared radiation from said optical elements to one of said elements of said dual element pyroelectric detector.
Claim 15
Dependent Claim
13 words
The method of claim 11 wherein said optical elements are fresnel lens elements.
Claim 16
Dependent Claim
17 words
The method of claim 12 wherein said plurality of fresnel lens elements comprising two fresnel lens elements.
References Cited (Backward Citations)
US4841284A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2001-10-05 | 2002-04-06 | 2002-10-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-10-05 | 2006-04-06 | 2006-10-06 | $3760.00 | Window Closed / Lapsed |
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