Passive-type infrared detector with elongated detection areas
First Claim
1. A passive-type infrared detector which comprises:
- an infrared sensor;
a pair of optical element for defining detection areas opposed substantially 180°
to each other for the infrared sensor;
a pair of flat mirrors for directing infrared rays of light from the detection areas towards the infrared sensor.
1 Assignment
0 Petitions
Accused Products
Abstract
A passive-type infrared detector 1 includes an infrared sensor 3, a pair of lens elements (optical elements) 4R and 4L, a pair of mirrors 5R and 5L and a casing 2. The lens elements 4R and 4L are used to define detection areas a+ and a− opposed substantially 180° to each other for the infrared sensor 3. The mirrors 5R and 5L are used to direct infrared rays of light from the detection areas towards the infrared sensor 3. When this passive-type infrared detector 1 is installed at a position intermediate of an alert region, a combination of the infrared sensor 3, one of the lens elements 4R and one of the mirrors 5R is effective to monitor a range from one end of the alert region to the intermediate position whereas a combination of the infrared sensor 3, the other of the lens elements 4L and the other of the mirrors 5L is effective to monitor a range from the opposite end of the alert region to the intermediate position. Therefore, one half of the alert region may be a detection distance. Consequently, the lens elements 4R and 4L can have a reduced focal length, allowing the passive-type infrared detector 1 of a reduced outer size to monitor the long alert region.
20 Citations
12 Claims
-
1. A passive-type infrared detector which comprises:
-
an infrared sensor;
a pair of optical element for defining detection areas opposed substantially 180°
to each other for the infrared sensor;
a pair of flat mirrors for directing infrared rays of light from the detection areas towards the infrared sensor. - View Dependent Claims (2, 3, 4)
wherein the infrared sensor is arranged at an apex portion opposite to a bottom of the casing which is adapted to be mounted on a support surface, the flat mirrors are arranged at a portion between the bottom of the casing and the infrared sensor, and the optical elements are arranged on respective sides of the casing. -
3. The infrared detector as claimed in claim 1, wherein each of the optical elements is a narrow-type for defining an detection area encompassed by one or two fingers when viewed in plane.
-
4. The infrared detector as claimed in claim 3, wherein the infrared sensor comprises a pair of elements having respective outputs of opposite polarities and wherein the detection areas encompassed by each finger are made up of a pair of divided areas corresponding to the pair of the element and arranged horizontally.
-
-
5. An infrared detector which comprises:
-
a single casing;
a pair of infrared sensors housed within the single casing; and
a pair of optical elements housed within the single casing for defining detection areas opposed substantially 180°
to each other for the associated infrared sensors.- View Dependent Claims (6, 7, 8)
-
-
9. A passive infrared detector unit comprising:
-
a dome-shaped housing having a first side and a second side;
a first optical lens mounted on the first side;
a second optical lens mounted on the second side, an optical axis of each of the respective optical lenses are aligned on a common axis as they extend towards respective objective sides;
an infrared detector is mounted on an apex portion of the housing;
a first mirror mounted within the dome-shaped housing on the first side adjacent and below the first optical lens to direct the optical axis from the first optical lens to the infrared detector;
a second mirror mounted within the dome-shaped housing on the second side adjacent and below the second optical lens to direct the optical axis from the second optical lens to the infrared detector; and
a recessed bottom member on the dome-shaped housing for engagement with a support surface, wherein the respective first and second mirrors incline upward towards the infrared detector.
-
-
10. A passive infrared detector unit comprising:
-
a dome-shaped housing having a first side and a second side;
a first optical lens mounted on the first side;
a second optical lens mounted on the second side, an optical axis of each of the respective optical lenses are aligned on a common axis as they extend 180°
apart towards respective objective sides and provides elongated truncated detection areas;
an infrared detector having a pair of detector elements of opposite polarity connected in series is mounted on an apex portion of the housing for providing an output signal;
a first flat mirror within the dome-shaped housing directs the first optical axis from the first optical lens to the infrared detector; and
a second flat mirror within the dome-shaped housing directs the second optical axis from the second optical lens to the infrared detector, the first flat mirror has one end mounted below the first optical lens on the first side and it'"'"'s other end extending upward and inward to terminate below the infrared detector, the second flat mirror has one end mounted below the second optical lens on the second side and it'"'"'s other end extending upward and inward to terminate below the infrared detector. - View Dependent Claims (11, 12)
-
Specification