Motion detector
AssigneeAmerican IRIS Corporation
InventorJacob Fraden
Life of this patent
Estimating the term…
Abstract
A miniature passive infrared motion detector consists of an optical system, a pyroelectric polymer film and an electronic circuit. The optical system is made of a curved Fresnel lens and an elongated wave guide having a reflective inner surface. The polymer film is also curved with the same radius as the lens and has two interdigitized electrodes on the rear surface and one uniform electrode on the front surface. The front electrode is covered with infrared absorbent material. The electronic circuit contains a differential amplifier and a threshold detector.
Claims22
A passive radiation motion detector which is capable of sensing thermally radiated energy from a moving object, comprising, in combination:
- a housing having an open front end;
- a focusing lens mounted within the front end of said housing, said focusing lens having a curved surface;
- a sheet of pyroelectric material positioned within said housing and having a curved surface with substantially the same radius of curvature as that of said focusing lens, said sheet of pyroelectric material being located behind said lens at a distance approximately equal to the focal length of said lens;
- at least one area of electrically conductive layer on one surface of said pyroelectric material forming at least one first electrode;
- at least one area of electrically conductive layer on the opposite surface of said pyroelectric material forming at least one second electrode;
- and
- electrical circuit means for amplifing and processing electrical signals produced at said electrodes.
A passive radiation motion detector which is capable of sensing thermally radiated energy from a moving object, comprising, in combination;
- a housing having an open front end;
- a flexible focusing lens positioned within the front end of said housing;
- a flexible sheet of pyroelectrical material positioned behind said focusing lens, said focusing lens and said sheet of pyroelectric material being arranged so as to form opposite sides of a cylinder having a diameter approximately equal to the focal length of said lens;
- a first electrode comprising an electrically conductive layer covering one surface of said pyroelectric material facing said focusing lens;
- a second electrode comprising two approximately equal areas of electrically conductive material arranged on the opposite side of said pyroelectric material;
- and
- electrical circuit means for amplifying and processing electrical signals produced at said electrodes.
Dependencies are inferred from the claim text.