Lens for pet rejecting passive infrared sensor
A passive infrared motion detection sensor that includes a Fresnel focusing arrangement that creates at least a first infrared sensing region, a second infrared sensing region, and a third infrared sensing region, in which target detection in one or more infrared sensing regions is weighted to be distinguishable from target detection in remaining infrared sensing regions. The Fresnel focusing arrangement creates the weighted infrared sensing regions using a lenslet region, an optically opaque region and a plurality of extruded cylindrical lenslets that extend across a portion of both the lenslet region and the optically opaque region. The signal detection in at least the second weighted infrared sensing region, for example, an infrared sensing range between 6 and 10 feet, is weighted to easily distinguish between a pet within the second infrared sensing range and a person at any infrared sensing range.
1. An infrared sensor, comprising:
an infrared detector; and
a Fresnel focusing arrangement, comprising:
an optically opaque region,
a lenslet region, and
a plurality of extruded cylindrical lenslets, extending across a portion of both the lenslet region and the optically opaque region,
wherein the Fresnel focusing arrangement is configured to focus infrared radiation emitted by a target onto the infrared detector, and
wherein infrared radiation focused onto the infrared detector from a field relative intensity pattern region including the plurality of extruded cylindrical lenslets extended across the lenslet region is weighted.
2. The infrared sensor of claim 1 , wherein,
the lenslet region focuses infrared light onto the infrared detector to create a first far field relative intensity pattern region; and
the field relative intensity pattern region is a second far field relative intensity pattern region.
3. The infrared sensor of claim 2 , wherein the first far field relative intensity pattern region corresponds to a sensing distance of the sensor between 10 and 20 feet.
4. The infrared sensor of claim 2 , wherein the second far field relative intensity pattern region corresponds to a sensing distance of the sensor between 0 and 10 feet.
5. The infrared sensor of claim 2 , wherein the second far field relative intensity pattern region corresponds to a sensing distance of the sensor between 6 and 10 feet.
6. The infrared sensor of claim 2 , wherein a target in the weighted second far field relative intensity pattern region can be distinguished from a target in the first far field relative intensity pattern region.
7. A method to control an infrared sensor, comprising:
focusing infrared light onto an infrared detector using a lenslet region to create a first far field relative intensity pattern region; and
focusing infrared light onto an infrared detector using the lenslet region and a plurality of extruded cylindrical lenslets to create a second far field relative intensity pattern region,
wherein the focused infrared light from the second far field relative intensity pattern region is weighted.
8. The method of claim 7 , wherein the first far field relative intensity pattern region corresponds to a sensing distance of the sensor between 10 and 20 feet.
9. The method of claim 7 , wherein the second far field relative intensity pattern region corresponds to a sensing distance of the sensor between 0 and 10 feet.
10. The method of claim 7 , wherein the second far field relative intensity pattern region corresponds to a sensing distance of the sensor between 6 and 10 feet.
11. The method of claim 7 , wherein a target in the weighted second far field relative intensity pattern region can be distinguished from a target in the first far field relative intensity pattern region.
12. A system to detect and distinguish a target using an infrared sensor, comprising:
an infrared detector;
a Fresnel focusing arrangement comprising:
an optically opaque region,
a lenslet region, and
a plurality of extruded cylindrical lenslets, extending across a portion of both the lenslet region and the optically opaque region,
wherein infrared radiation emitted by a target focused onto said infrared detector from a field relative intensity pattern region including the plurality of extruded cylindrical lenslets extended across the lenslet region is weighted; and
a smart home controller, coupled to the infrared detector, configured to detect and distinguish the target based upon the weighted focusing of infrared radiation.
13. The system of claim 12 , wherein,
the Fresnel focusing arrangement focuses infrared light onto the infrared detector to create a first far field relative intensity pattern region, and
the field relative intensity pattern region is a second far field relative intensity pattern region.
14. The system of claim 13 , wherein a target in the weighted second far field relative intensity pattern region can be distinguished from a target in the first far field relative intensity pattern region.