UNA DISPOSICIËN EN SEMICONDUCTORES

摘要

881,571. Semi-conductor devices. STONE & CO. (DEPTFORD) Ltd., J. Aug. 25, 1959 [Sept. 25, 1958], No. 30742/58. Class 37. A semi-conductor device is mounted by way of a heat-sink metallic body on a supporting metal wall, a thin disc or sheet of mica, micanite, &c. being interposed between the body and the wall to insulate them electrically from one another while not seriously reducing the thermal conduction between them. As shown, Fig. 2, an encapsulated germanium diode 6 has a copper base with a threaded stub 7 by means of which the diode is mounted on a raised pad 2 on the internal surface of the wall 1 of a rectifier box 20, the stub passing through apertures in a copper disc 8 and a thin mica disc 4 and being insulated from the wall 1 by a bush 10 and washer, moreover the pad 2 is counterbored around the aperture therein. Copper disc 8 is provided with a terminal, and silicone grease may be coated on the mating surfaces of copper and mica. The end of the stub 7 is secured by a nut 17 within a recessed boss 3 on the external surface of the wall 1, the remaining space in the recess being filled with pitch or solid-setting insulating compound which is covered by an aluminium disc 19. The optimum size for mica disc 4 is twelve times the area of the base of the rectifier 6. Box 20 may be made of cast aluminium and may contain a plurality of diodes, being closed by a lid 21, mating surfaces of lid and box being machined flat and the box and lid being anodised. Cable entries may be screwed into the box at the level of a terminal board inside the box. Such an arrangement may be mounted on the underframe of a vehicle. Fig. 3 shows a plurality of silicon diodes 61 mounted by stubs 71 and locking strips 711 on a common copper or aluminium alloy body 81 separated from a single pad 21 by a common punched sheet 41 of mica &c., heat dissipating fins 23 being provided on the outside of wall 1. For rectification of a three-phase system, three silicon rectifiers of each polarity may be mounted on two separate bodies 81 which act as positive and negative bus-bars and are secured to pad 21 through a common insulating sheet, the box 1 also accommodating ancillary equipment, e.g. a voltage regulator. Transistors may be mounted on the stem of a T-shaped body of copper or aluminium alloy, the head of the T being mounted, through the mica, against the pad.