| 摘要 |
674,530. Printed circuits. BRITISH TABULATING MACHINE CO., Ltd. Feb. 28, 1950 [March 8, 1949], No. 5085/50. Class 36. [Also in Group XIX] Conductors 320, 322 may be applied to both surfaces of an insulating sheet 308 by painting, printing, stencilling or otherwise depositing thereon a liquid conductive composition. The conductors may be pressed into the surfaces of the sheet (Fig. 20) by applying heat and pressure, which may also serve to complete the curing of the sheet where this consists of, for example, a partially cured phenol condensate. Transverse connections 324 between conductors on opposite sides of the sheet may be made by piercing the sheet at the appropriate point and depositing some of the conductive composition in the hole. A socket for the reception of a plug 326 may be made by inserting a bung 328 in a metallized hole prior to the pressing operation, in order to retain a transverse passage having substantially cylindrical walls. A number of such sheets may be stacked together and bonded to a unitary whole by a moulding process. |
