| 摘要 |
<p>1,246,443. Lasers; resistors. FERRANTI Ltd. 15 Aug., 1968 [23 Aug., 1967], No. 38816/67. Headings H1C and H1S. [Also in Division C7] In a coating process wherein material is deposited from a gaseous atmosphere on to selected areas of a substrate, the said selected areas are irradiated using a laser, the duration and intensity of the irradiation being such that the temperature of these areas exclusively is high enough to cause deposition of a layer of material of the desired thickness. The laser may be a pulsed-output ruby laser emitting light in the I.R. or visible red region of the spectrum, and the selected areas are defined by using a phase- or amplitude-variable hologram. The process may be used for making thin-film carbon resistors. In the Figure, a chamber 12 has an alumina substrate placed on base 10, and following evacuation through pipe 15, benzene vapour is admitted through pipe 13, possibly together with diluent argon from 22. Radiation from pulsed-output ruby laser 17 and co-operating phase-variable hologram 18 passes through bloomed window 20 so that selected areas of surface 21 of the substrate are heated sufficiently to cause deposition of carbon thereon in narrow zig-zag configurations, which, after separation from each other with a scribing tool constitute thin-film resistive elements.</p> |
