Abstract: An infrared radiation detector comprises a pyroelectric detector element in a hermetically sealed housing. The housing comprises a base and a cover. The cover has an aperture surrounded by an inwardly directed flange. A self-locating window capable of transmitting infrared radiation is fastened to the flange with adhesive to close the aperture. The window comprises a first portion which is adapted to fit within and which is located within the aperture. A second wider portion forms a peripheral shoulder which bears against the cover's flange. The second portion of the window is present outside the cover, giving a wide field of view.

Abstract: A pyroelectric infrared radiation detector which is particularly suited to automated assembly comprises a pyroelectric detector element mounted in a housing having a window transparent to infrared radiation. Electrically conductive leads in a single-in-line configuration extend through a base portion of the housing for making external electrical connections to the detector. One lead has an extended portion within the housing. The extended portion provides a cantilever support to which the detector element is fastened. The leads may all be formed from portions of a unitary lead frame. A second differentially connected pyroelectric detector element may be fastened to another cantilever support formed by a portion of the same lead frame. The cantilever supports preferably extend from an insulating block which encapsulates an associated electrical component and which also provides support for the detector elements.

Abstract: An infrared radiation detector for an intruder alarm has a pyroelectric element comprising a pyroelectric body sandwiched between two electrodes. The element is supported above a header by two leads of a microminiature circuit package. The package is mounted on its back on the header. One lead of the circuit package is electrically connected to the element. The other lead is insulated from the element. A second pyroelectric element may similarly be supported by two leads of the package.

Abstract: An infra-red radiation detector comprises an envelope in the form of a dewar (1,2) in which a vacuum space (12) is present between an outer wall (2) and inner wall (1) cooled by a cooling element (20). Gas molecules are gettered from the vacuum space (12) by at least one shaped molecular-sorbent porous body (10,10') having a major surface which fits onto and is bonded to a cooled surface (e.g. of a radiation shield 8) associated with the cooled inner wall (1). The shaped getter body (10,10') is secured (e.g. by epoxy adhesive) at its major surface to this cooled surface in a heat-exchange relationship so as to be cooled by the cooling element (20) during operation of the detector. The shaped getter body (10,10') is preferably a moulded annulus of synthetic zeolite material.