US3792275A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Infrared intrusion sensor
Assignee: Barnes Engineering Co
•
Filing: 1972-12-26
•
Granted: 1974-02-12
•
Expires: 1992-12-26
Abstract
Abstract An infrared intrusion sensor is provided to detect a human target anywhere in a 20 X 20 foot area. A wide angle portraittype lens of germanium is utilized to provide reasonably uniform imaging over the field of view of approximately 70* X 70*, while still focusing on a flat image plane. This allows the use of a flat, extended thermopile detector having all active junctions which are arranged in columns to cover the desired area, and connected so that the columns alternate in a positivenegative configuration. The detector junctions have different sizes and spacing, with the junction concentration being roughly inversely proportional to the square of the range.
Inventors
- 👤 R Leftwich
- 👤 R Ensor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 02:26
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/18; G08B13/189; G08B13/19; G08B13/193; Y; Y10; Y10S; Y10S250/00; Y10S250/01
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
120 words
An infrared intrusion sensor for providing high sensitivity covering a wide field of view, comprising a. a wide angle lens having a high refractive index for providing reasonably uniform imaging over a wide field of view and being focused on a flat image plane, b. an extended flat infrared detector located on said flat image plane, c. said detector having a plurality of all active detector elements arranged in columns to fill the area covered which are connected to be alternately positive- and negative-going on being activated by an intruder, d. said detector elements having a different spacing and size with the greatest density and smallest elements being located where the greatest range is encountered and the greatest sensitivity required.
Claim 2
Dependent Claim
120 words
An infrared intrusion sensor for providing high sensitivity covering a wide field of view, comprising a. a wide angle lens having a high refractive index for providing reasonably uniform imaging over a wide field of view and being focused on a flat image plane, b. an extended flat infrared detector located on said flat image plane, c. said detector having a plurality of all active detector elements arranged in columns to fill the area covered which are connected to be alternately positive- and negative-going on being activated by an intruder, d. said detector elements having a different spacing and size with the greatest density and smallest elements being located where the greatest range is encountered and the greatest sensitivity required.
Claim 3
Dependent Claim
17 words
The infrared intrusion sensor set forth in claim 1 in which said wide angle lens is germanium.
Claim 4
Dependent Claim
22 words
The infrared intrusion sensor set forth in claim 1 wherein said lens has a plane front surface and a convex back surface.
Claim 5
Dependent Claim
22 words
The infrared intrusion sensor set forth in claim 1 wherein said infrared detector is a thermopile comprised of all active junction thermocouples.
Claim 6
Dependent Claim
18 words
The infrared intrusion sensor set forth in claim 4 wherein said all active junction thermocouples are serially interconnected.
Claim 7
Dependent Claim
76 words
The infrared intrusion sensor set forth in claim 1 wherein the area to be covered is divided into three zones with the close zone underneath the lens having detector elements which are larger and wider spaced, with size and spacing being reduced and the number of elements increased in the next immediate zone, and the spacing and size reduced further and the number of elements being substantially increased in the zone farthest distance from said lens.
Claim 8
Dependent Claim
25 words
The infrared intrusion sensor set forth in claim 1 wherein the concentration of detector elements is roughly inversely proportional to the square of the range.
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) | 1977-02-11 | 1977-08-13 | 1978-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-11 | 1981-08-13 | 1982-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-11 | 1985-08-13 | 1986-02-12 | $7700.00 | Window Closed / Lapsed |