US PATENT SUBCLASS 313 / 337
.~ Indirectly heated cathodes

Current as of: June, 1999
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313 /   HD   ELECTRIC LAMP AND DISCHARGE DEVICES

326  DF  ELECTRODE AND SHIELD STRUCTURES {14}
337.~ Indirectly heated cathodes {3}
338  DF  .~.~> Plural separate cathode sections
339  DF  .~.~> Interior emissive hollow cathodes
340  DF  .~.~> Insulating material between heater and cathode

DEFINITION

Classification: 313/337

(under subclass 326) Cathodes which include a cathode member and a source of heat energy for heating the cathode member, the heating means being a member or device separate from the cathode member.

SEE OR SEARCH THIS CLASS, SUBCLASS:

270, and the subclasses specified in the notes thereto for devices under the class definition which include supporting and/or spacing structure for an indirectly heated cathode.

305, for discharge devices provided with at least three electrodes, a cathode emitting electrons to a first anode which is heated by the space discharge, the heated anode having a surface which when heated emits electrons to a second anode (the third electrode). These devices are sometimes known as "cathanode" devices.

310, and the subclasses specified in the notes to the definition of that subclass for discharge devices which have an indirectly heated cathode.

336, where the cathode is designed so that the electron emission is restricted to a point-like area. 341+, for filaments and other resistance heated electrodes for electric lamps and space discharge devices.