US2686888A

US2686888A - Vacuum discharge tube

Info

Publication number: US2686888A
Application number: US255096A
Authority: US
Inventors: Warmoltz Nicolaas
Original assignee: Hartford National Bank and Trust Co
Current assignee: Hartford National Bank and Trust Co
Priority date: 1950-12-04
Filing date: 1951-11-06
Publication date: 1954-08-17
Anticipated expiration: 1971-08-17

Description

g. 17, 1954 N. wARMoLTz VACUUM DISCHARGE TUBE Filed NOV. 6. 1951 INVENTOR Nicolaas Wormolz Sym Patented Aug. 17, 1954 2,686,888 VACUUM DISCHARGE TUBE Nicolaas Warmoltz, Eindhoven, Netherlands, as-

signor to Hartford National Bank and Trust Company, Hartford, Conn., as trustee Application November 6, 1951, Serial No. 255,096

Claims priority, application Netherlands December 4, 1950 in which an incandescent cathode is arranged close to the anode by means of a thin insulator.

According to the invention, in a high-vacuum` discharge tube which comprises at least an anode` and a cathode arranged on oppositesides of and in contact with an insulator, the cold cathode, which has a smaller length than the anode, is arranged in contact with the insulator in such manner that the border line cathode-insulatorvacuum has the anode facing it on the opposite side of the insulator. This arrangement permits a rectifying effect to be obtained, since the field intensity on the border line cathode-insulatorvacuum is higher than that on the border line anode-insulator-vacuum. The anode preferably has a greater length than the insulator, so that the mutual conductance of the discharge tube is substantially reduced in the conductive direction, Border line cathode-insulator-vacuum is dened as the region at the terminus of a cold cathode mounted on an insulating member disposed in an evacuated envelope.

The longer the border line cathode-insulatorvacuum the more current the tube is capable of passing at a predetermined voltage. If there are on one side of the insulator several border lines cathode-insulator-vacuum between which the insulator is not interrupted, it is advisable to arrange at a small distance therefrom a supplementary electrode which may function as an auxiliary anode or as a control grid.

The invention will now be described more fully with reference to the accompanying drawing, in which:

Figs. 1 and 2 show an electric discharge tube according uto the invention in its simplest form.

Fig. 3 shows a discharge tube provided with an auxiliary electrode.

Figs. 4 and 5 show two sectional views of a tube according to the invention having a low mutual conductance, and

Figs. 6, '7 and 8 respectively show alternative embodimentsthereof.

Referring to Fig. 1, the tube comprises a glass bulb l, an anode rod 2 several mms. thick which is coated with a glass layer 3 of thickness 0.15 mm. and a cathode formed by a metal layer 4.

The tube shown in Fig. 2 is similar to that of Fig. 1 except for the cathode which is constituted by a ring so that two circular border lines cathode-insulator-vacuum are formed.

In the tube shown in Fig. 3 several rings 4 are mounted on the insulator 3 and a cylindrical auxiliary electrode 5 is provided in order that the electrons emanating on the cathode border lines may be discharged more readily.

Fig. 4 is a sectional view taken at right angles to the axis of the electrode system, 2 designating the anode rod, 3 the insulating layer and a number of strips Which are united by a ring and'extend in the direction of the axis of the anode.

Fig. 5 is a lateral view of this electrode system.

In the tube of Fig. 6 the cathode is formed by a conductive helix 8 mounted on the insulator 3, the auxiliary anode being again designated 5.

In the tube of Fig. 7, the anode is constituted by a flat plate 9 coated with a glass layer ID having mounted on it a number of parallel strips l I. The same arrangement is made both on the front and on the rear of the plate, and Fig. 8 is a crosssectional View of this electrode system, |12 designating the auxiliary electrode.

While the invention has been described in connection with specific examples and applications thereof, other modifications of the invention will be readily apparent to those skilled in the art Without departing from its spirit and scope as deiined in the appended claim.

What I claim is:

A high vacuum discharge tube comprising an evacuated envelope, an insulating member having opposite surface portions disposed Within the envelope, a cold emissive cathode comprising a plurality of longitudinally extending strips interconnected by a ring-shaped member disposed on one of said surface portions of the insulator, at

least one edge of one of said strips defining with said insulating member a border-line cathode insulator-vacuum and an anode disposed on the opposite surface portion of the insulator parallel to and facing the cathode, said anode being positioned to extend beyond said border-line cathodeinsulator-vacuum.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,188,194 Moore June 20, 1916 1,955,391 Schroter Apr. 17, 1934 1,991,632 Scofield Feb. 19, 1935 2,223,040 Mahl Nov. 26, 1940 2,409,716 Slock et a1. Oct. 22, 1946