US2870365A

US2870365A - Glow-discharge tube

Info

Publication number: US2870365A
Application number: US664750A
Authority: US
Inventors: Frouws Simon Mari
Original assignee: US Philips Corp
Current assignee: US Philips Corp; North American Philips Co Inc
Priority date: 1956-06-22
Filing date: 1957-06-10
Publication date: 1959-01-20
Anticipated expiration: 1976-01-20

Description

Filed June 10,

INVENTOR SIMON MARI FROUWS United States Patent GLOW-DISCHARGE TUBE Simon Mari Frouws, Eindhoven, Netherlands, assignor to North American Philips Company Inc., New York, N. Y., a corporation of Delaware Application June 10, 1957, Serial No. 664,750 Claims priority, application Netherlands June 22, 1956 2 Claims. (Cl. 313-497) This invention relates to glow-discharge tubes, in which the main anode and an auxiliary electrode are arranged one at each side of a plate-shaped cathode.

In known tubes, in which the cathode is provided between the anode and the auxiliary electrode, the latter extends partially into the space between the anode and the cathode through an opening of the cathode, the auxiliary electrode being used as an auxiliary anode. These tubes suffer from a disadvantage in that, when applying an alternating voltage between the anode and the cathode and the auxiliary anode has a given positive bias, a breakdown is able to occur in the wrong sense in the main discharge path even without a control voltage on the auxiliary anode, which breakdown is initiated by a breakdown between the auxiliary anode and the main anode.

According to the invention, in a glow-discharge tube in which the main anode and an auxiliary electrode are located one at each side of the plate-shaped main cathode and the auxiliary electrode extends into an opening of the cathode, this opening is provided with a preferably conical rim which extends away from the anode and into which the wire-shaped auxiliary electrode extends without projecting from the surface of the cathode.

By the construction according to the invention it is ensured that the auxiliary discharge is somewhat shielded from the anode field. This results in that no breakdown occurs in the wrong sense in the main discharge path during the auxiliary discharge at a negative anode voltage. This permits an alternating voltage of 220 v. 50 c./s. to be applied between the anode and the cathode with a continuous auxiliary discharge without the rectitying efiect being lost. Furthermore, the disadvantage of direct ignition between the anode and the auxiliary electrode is obviated. A further advantage is that, in the case of the auxiliary electrode acting as an auxiliary cathode, the auxiliary discharge extends to and on the wire-shaped auxiliary electrode behind the cathode (viewed from the anode) with a stronger auxiliary current. As a result, the ignition voltage is not reduced 2,870,365 Patented Jan. 20, 1959 'icg more than in the case of a small auxiliary current. Hence, the ignition voltage of the main anode depends less upon the value of the auxiliary current than in known arrangements. Even if the auxiliary electrode acts as an auxiliary anode this occurs a degree.

In order that the invention may be readily carried into effect, an example will now be described in detail with reference to the accompanying drawing, in which Fig. 1 is a vertical cross-section through the tube and Fig. 2 a horizontal cross-section through the cathode. In Fig. l a number of lead-through pins 2 are sealed into the bottom of a glass bulb 1. A cathode 3 has an opening 4 with a conical rim into which an auxiliary electrode 5 extends in the form of a thin wire. The supply conductors for the cathode and the auxiliary electrode are surrounded by glass tubes in order to avoid short-circuits. The graphite anode 6 is provided on a supply conductor completely covered with enamel 7. The enamel layer is thicker at its end as shown at 8, where an electrode screen 9 is secured to it. A flexible wire 10 is secured to one of the supply conductors and rests against the wall of the tube. The wire 10 contacts the layer 12 which is produced on the wall as a result of the cathode disintegration at a high current density. The reference numeral 11 designates a radio-active preparation for avoiding ignition delays. The cathode and the auxiliary electrode consist of molybdenum. The anode screen consists of nickel. The tube is filled with a mixture of neon and 25% argon at a pressure of 75 mms. The dimensions of the electrodes and their distances may be derived from the scale shown in the drawing.

What is claimed is:

1. A glow-discharge tube comprising an envelope filled with an ionizable gaseous medium, an anode electrode, a plate-like cathode electrode having an aperture therein and an outwardly extending flange-like rim surrounding said aperture on the side of the cathode remote from the anode, and an auxiliary electrode extending into the aperture in the cathode through said rim-like flange.

2. A glow-discharge tube comprising an envelope filled with an ionizable gaseous medium, an anode electrode, a plate-like cathode electrode having an aperture therein and an outwardly extending conical flange-like rim surrounding said aperture on the side of the cathode remote from the anode, and an auxiliary electrode extending into the aperture in the cathode through said rim-like flange.

References Cited in the file of this patent UNITED STATES PATENTS 2,560,346 Holdaway July 10, 1951 2,560,347 Peck July 10, 1951 2,560,348 Stieritz July 10, 1951 2,662,993 Malter Dec. 15, 1953