GB1440674A - Pyroelectric effect devices - Google Patents

Abstract

1440674 Pyroelectric devices; image pick-up tubes DEFENCE SECRETARY OF STATE FOR 22 May 1974 [23 May 1973] 24557/73 Headings H1K and H1D In a pyroelectric device, e.g. as shown in Fig. 1, an infra-red detector, to compensate for insensitivity due to inadequate absorption in the 8 to 13 micron infra-red band by plate 1 of pyroelectric material, a layer 2 of an organic or organosilicon polymer which is more absorbent in the said band is in thermal contact with plate 1. The pyroelectric material may be single crystal or polycrystalline lead germanate or lead germanate silicate, and has an average thickness not greater than 100 microns. Single crystal material is cut with the major surfaces perpendicular to the trigonal C-axis. The absorbent layer has an average thickness less than that of the pyroelectric layer and may be p.v.c. or polyvinylidene fluoride applied as a solution or as a melt, or polymers of cyclohexane, acetone, hexene-1, diethyl ethers or hexamethyldisiloxane applied by vapour or plasma deposition. The charge on pyroelectric layer 1 resulting from irradiation appears on absorbent layer 2 by conduction or tunneling and is detected by conventional means connected to opaque nickel-chromium electrode 3 and transparent gold electrode 5. The device may alternatively be the target of an infra-red camera tube, as shown in Fig. 5, wherein layer 21 is the pyroelectric material, layer 22 the abosorbent material and layer 23 the single nickel-chromium electrode.