US2038341A - Electron discharge device - Google Patents

Description

April 21, 1936. 5 BRUCHE 23038341 ELECTRON DISCHARGE DEVICE Filed May 25, 1955 INVENTOR ERNST BRUCHE Patented Apr. 21, 1936 UNITED STATES PATENT OFFICE ELECTRON DISCHARGE DEVICE many Application May 23, 1935, Serial No. 22,955 In Germany June 7, 1934 3 Claims. (Cl. 25027.5)

My invention relates to electron discharge devices of the gas type, more particularly to improvements in oxide coated cathodes therefor.

The conventional type of oxide-cathode mount- 6 ed in gas discharge tubes may have the oxide coating destroyed as a result of the impact of positive ions. Two methods have been employed to prevent this result. One is to apply the oxide material upon a wire in the axis of the path of 10 the electron stream or beam, while according to the other method the cathode surface bearing the oxide is positioned annularly about the beam of reversely flowing ions. In the second case, in more detail, a flat band or strip is dis- 15 posed around the axis of the electron beam or rays, or a small pot or cup may be positioned in the path of the rays so that the lateral surfaces or walls thereof will no longer be struck by the mm.

20 The principal object of my invention is to provide an improved type of oxide coated cathode for gaseous discharge devices.

According to the present invention the oxide coating on the cathode is more efiectively shield- 25 ed from the impacts of positive ions than in conventional type tubes. The oxide substance is placed upon the face of the cathode sheet or strip turned away from the anode. The lines of force passing from the anode to the cathode sheet at- 30 tract the electrons in the path of the ray or beam and guide the same to the anode. According to the invention, apart from excellent protection of the oxide, it is possible to use various types of planar cathodes known in the art which 35 may have the form of sheets or laminae either heated directly or indirectly.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims, but the in- 40 vention itself will best be understood by reference to the following description taken in connection with the accompanying drawing in which Figure l is a schematic vertical section of an electron discharge device embodying my inven- 45 tion; Figure 2 is a perspective of the electron discharge device shown in Figure 1; and Figure 3 is a schematic vertical section of a modification of the electron discharge device shown in Figure 1 and embodying my invention.

50 Referring to Figure 1 the electron discharge device has an envelope e containing an anode or plate a provided with aperture (1' and the control sheet 8, the anode and control sheet being on opposite sides of cathode is. On the face of the 55 cathode It turned away from the anode is a cylinder or sleeve secured concentrically about the aperture 70' in the cathode sheet, the inner surface of said cylinder being coated with oxide at p. The radius of the cylinder is larger than that of the hole and is surrounded by heater h. 5 The lines of force act, as shown, thru the cathode sheet and draw the electrons out. The cathode could also be provided with several holes around which oxide material is disposed. Of course, opposite each of such holes must be a corresponding one in the anode.

In the modification in Figure 3 the oxide p of the cathode is is here applied or coated directly upon the posterior face of the cathode sheet is. The small metal block s serves as a control sheet. A heater h is provided.

While I have indicated the preferred embodiments of my invention of which I am now aware and have also indicated only one specific application for which my invention may be employed, it will be apparent that my invention is by no means limited to the exact forms illustrated or the use indicated, but that many variations may be made in the particular structure used and the purpose for which it is employed without departing from the scope of my invention as set forth in the appended claims. I

What I claim as new is:-

1. A gas discharge device having an envelope containing an anode and a cathode, said cathode being formed of sheet material and provided with an aperture, said anode being positioned on one side of said cathode and a cylinder mounted on the other side of said cathode at right angles to the cathode sheet and around said aperture, and an oxide coating on the inner surface of said cylinder.

2. A gas discharge device having an envelope containing a fiat cathode provided with an aperture, a flat anode positioned on one side of and parallel to said cathode, an oxide coating provided on the opposite side of said cathode from said anode, means for heating said cathode and a control electrode positioned on the coated side of said cathode.

3. A gas discharge device having an envelope containing a flat disc-like cathode provided with a single aperture, a flat disc-like anode positioned on one side of and parallel to said cathode, an oxide coating disposed on said cathode on the opposite side of said anode, means for heating said cathode, and a control electrode positioned on the same side of said cathode as said oxide coating.

ERNST BRUCHE.

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