A thermal imaging device and a method of manufacturing a thermal imaging device

Claim 1

A thermal imaging device comprising a slab of ferroelectric or pyroelectric material having an infra-red-permeable common electrode on one main surface and signal electrodes on the opposite main surface, the signal electrodes being electrically connected to respective electrodes of a circuit substrate by means of conductors surrounded by a thermally insulating material, characterized in that each conductor is a metal coating on a bore in a respective pillar of the insulating material.

Claim 5

A method of manufacturing a thermal imaging device, the method comprising the steps of providing a slab of ferroelectric or pyroelectric material with an infra-red-permeable common electrode on one main surface and with a signal electrode layer on the opposite main surface, characterized in that a sheet of electrically and thermally insulating material is bonded to the signal electrode layer, an electrically conductive layer is provided on the insulating sheet, a first photoresist layer is provided on the electrically conductive layer, the first photoresist layer is exposed and the exposed resist is developed so as to form an array of spaced apertures, bores disposed in accordance with this array are down to the signal electrode layer, an electrically conductive coating is provided on the surface of each bore so as to electrically connect the signal 1 electrode layer to the electrically conductive layer on the insulating sheet, the remainder of the first photoresist layer and any superposed electrically conductive coating material are removed, a second photoresist layer is provided on the electrically conductive layer on the insulating sheet so as to close the open ends of the bores, the second photoresist layer is exposed and the exposed resist is developed so as to form a pattern of channels which define islands of photoresist, wherein each island is disposed over and around a respective bore, channels are produced which extend down to the ferroelectric or pyroelectric slab so as to form pillars of insulating material which are each coaxial with a respective shield electrode, wherein each pillar surrounds a respective bore in the insulating material, the remainder of the second photoresist layer is removed and conductor elements of a circuit substrate are bonded each to a respective electrically conductive layer on a respective pillar by means of solder bumps.

Claim 6

A method of manufacturing a thermal imaging device, the method comprising the steps of providing a slab of ferroelectric or pyroelectric material with an infra-red-permeable common electrode on one main surface and with a signal electrode layer on the opposite main surface, characterized in that a sheet of electrically and thermally insulating material is bonded to the signal electrode layer, an electrically conductive layer is provided on the insulating sheet, a first photoresist layer is provided on the electrically conductive layer, the first photoresist layer is exposed and the exposed resist is developed so as to form an array of spaced apertures, bores disposed in accordance with this array are down to the signal electrode layer, an electrically conductive coating is provided on the surface of each bore so as to electrically connect the signal 1 electrode layer to the electrically conductive layer on the insulating sheet, the remainder of the first photoresist layer and any superposed electrically conductive coating material are removed, a second photoresist layer is provided on the electrically conductive layer on the insulating sheet so as to close the open ends of the bores, the second photoresist layer is exposed and the exposed resist is developed so as to form a pattern of channels which define islands of photoresist, wherein each island is disposed over and around a respective bore, channels are produced which extend down to the ferroelectric or pyroelectric slab so as to form pillars of insulating material which are each coaxial with a respective shield electrode, wherein each pillar surrounds a respective bore in the insulating material, the remainder of the second photoresist layer is removed and conductor elements of a circuit substrate are bonded each to a respective electrically conductive layer on a respective pillar by means of solder bumps.

Claim 9

A method as claimed in any of Claims 3 to 5, wherein the insulating sheet is bonded to the signal electrode material by means of a thermosetting adhesive.

Claim 10

A method as claimed in any of Claims 3 to 6, characterized in that the thermally insulating sheet consists of a stack of thermally insulating plates bonded together by means of adhesive films which are disposed one between each pair of opposed plates.