| 摘要 |
A motion-activated decorative lighting fixture with a PIR motion detector having an adjustable field of view hidden behind a decorative slotted wall of the fixture body. The lighting fixture includes a motion detector housing that forms an integral part of the fixture body. The housing includes a slotted vertically extending exterior wall around the housing with an array of elongate vertically extending slots horizontally spaced apart from one another and extending along at least a portion of the wall. One or more PIR sensors are disposed within the housing, and a segmented Fresnel lens array is disposed within the housing behind the slots to direct infra-red energy from a monitored field of view to a sensor. The lens array includes a plurality of columns of lenslets, which are divided into at least two sets of columns, the columns of the first set alternating with the columns of the second set so as to form an alternating sequence of columns. At least a portion of the columns of each set have at least two lenslets disposed one above the other. Each column is aligned with a corresponding slot so as to direct infra-red energy from a monitored zone passing through the corresponding slot to a sensor. The configuration defines an optical path for infra-red energy emanating from a detection zone in the field of view, the optical path passing through a given slot and a lenslet aligned with the slot and on to a PIR sensor. The lens array and the wall are mounted for relative rotary movement with respect to one another between at least a first position and a second position. The columns and slots are disposed such that in the first relative position of the lens array and slots each column of the first set is aligned with a corresponding slot while the columns of the second set are substantially blocked by the wall. In the second position each column of the second set is aligned with a corresponding slot and the columns of the first set are substantially blocked by the wall. In this way the lenslets of the columns of the first and second sets define alternative fields of view that may be switched in at the user's choice.
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