US 3212169

Patent Overview — US 3,212,169

Title: Grid electrode structure and manufacturing method therefor

Patent number: US 3,212,169 A

Inventors: Harold K. Glaser and Charles F. Emery (Horseheads, N.Y.)

Assignee: Westinghouse Electric Corporation, East Pittsburgh, Pa. (original assignee; the source notes assignee listings may be inaccurate)

Key dates: Application filed 1962-02-09 (Ser. No. 172,192); priority date 1962-02-09; granted/publication 1965-10-19; a corresponding GB priority (GB48897/62A, published as GB956956A) is listed as filed 1962-12-28. Legal status shown as expired.

Purpose: To provide a rigid frame (planar) grid electrode and a manufacturing method yielding lateral wires of uniform diameter and uniform spacing. The stated motivation is that electron-discharge-device performance, especially transconductance, depends on cathode-to-grid spacing and on the diameter of, and spacing between, grid lateral wires. Fine wires are not self-supporting, so they are wound on a support frame.

Plain-language scope: A molybdenum frame is plated with copper (about .00003–.00005 inch) and then gold (about .00009–.00011 inch). Gold-coated tungsten lateral wires (gold about 4% by weight) are wound over two such frames using a jig; cut wire ends are tacked with a volatile bonding agent such as Lucite. The unit is heated in a non-oxidizing atmosphere (Ammogas, a Westinghouse trademark for dissociated ammonia, or hydrogen) for two minutes at 930°C, producing a gold-copper solid solution that brazes the wires to the frame. The described advantages are that the wire's gold coating does not flow (preserving uniform wire diameter), the low brazing temperature avoids recrystallization of the molybdenum frame, the bond resists remelting below the original bonding temperature, and the plated frame can suppress secondary emission. The excerpt also describes the broader method of winding fine gold-plated tungsten wire on a copper-and-gold-coated molybdenum support, heating in a non-oxidizing atmosphere to form a gold-copper solid solution, and cooling to secure the turns.

Source: https://patents.google.com/patent/US3212169/en

What the excerpt does not establish: It does not provide the full claim set, complete drawing descriptions, exact claim language beyond the summarized statements, prosecution history, or any information on litigation, ownership transfers, validity, or prior art beyond the background discussion of prior gold-coated-frame methods.