| 摘要 |
1,166,285. Resistors. SOC. D'ELECTRONIQUE ET D'AUTOMATISME. 3 Nov., 1966 [8 Dec., 1965], No. 49348/66. Heading HIS. [Also in Division C1] An oxide film resistance element comprises a layer of non-stoichiometric tin oxide bonded to an insulating substrate, the resistivity of the material of the film decreasing continuously from the substrate surface outwards either to a point intermediate the surface of the film and the substrate (after which the resistivity may increase) or to the film surface. The film is formed by spraying solution from containers 1 and 2 through an atomizing jet 4 on to a heated substrate carried on plate 7 (which may be rotated) in an oven 6 maintained at a predetermined temperature (550-600‹ C.). Container 1 holds an oxidizing reagent (zinc oxide), tin chloride and a doping impurity (aluminium chloride) in distilled or de-ionized water mixed with hydrochloric acid. Container 2 contains a similar solution without the oxidizing reagent. To begin only the solution from container 1 is used the mist produced forming a high resistivity tin oxide layer on the substrate by pyrolytic dissociation. Mixer cock 3 is then moved so that an increasing quantity of solution from container 2 with a correspondingly decreasing quantity from 1 is delivered to jet 4 to produce a progressive reduction in the resistivity of the oxide deposited on the substrate. The resistivity is arranged to fall from a peak at the substrate surface to a low level at the surface of the finished film or at a point within the film from which it may increase to another peak which may be at the film surface. The solution is forced from containers 1 and 2 by air pressure under control of cock 11. Switch 13 controlling a motor 12 operating cock 3 may be linked mechanically to cock 11. The rotation of motor 12 or of cock 3 may be controlled in accordance with a required programme. |
