GB1508299A - Pyroelectric detectors - Google Patents

Abstract

1508299 Pyroelectric detectors; image pick-up tubes MULLARD Ltd 20 June 1975 [20 March 1974 2 Sept 1974] 12333/74 and 38214/74 Headings H1D and H1K A pyroelectric detector for a thermal image camera tube comprises a substrate 2 supporting a layer 8 of pyroelectric material which is deposited on a nucleating layer 7, which is wetted by a solution of the pyroelectric material so as to form a continuous film on the nucleating layer. The pyroelectric layer 8 may be a 0À5- 5Á thick layer of TGS. The nucleating layer 7 may be Al and it may be formed on a magnesium fluoride layer 4 and a Ni-Cr electrode layer 3 as a mosaic of spaced portions, using photoresist. The magnesium fluoride layer 4 is covered with the photoresist, which defines the mosaic, and then contacted with the TGS solution, after which the photoresist is removed to leave a pattern of spaced TGS portions. The substrate 2 may be a polyamide resin which is spun on to a glass slide and cured, and the glass slide etched away to leave a 0À05-0À3Á thick membrane which serves as the substrate 2. The nucleating layer 7 of A1 may form one electrode of the detector, or alternatively, the nucleating layer 7 may be magnesium fluoride or other stated substances. The ratio of the thickness of the pyroelectric material 8 and the substrate 2 is greater than 10 and the ratio of the width of the TGS portions in the mosaic and the gap between the portions is between 5 and 12. The membrane forming the substrate 2 may be supported by posts which tension the membrane and reduce oscillations induced in it, or the membrane may be supported between two metal ring electrodes.