US2239022A - Electron discharge tube - Google Patents

Description

H. STRUBIG 2,23 9,022

ELECTRON DI SCHARGE TUBE Filed March 22, 1958 2 Sheets-Sheet 1 F f *muam' aii iiiiiiiii April 22, 1941. H. STRUBIG 2,239,022

ELECTRON DISCHARGE TUBE Filed March 22, 1958 2 Sheets-Sheet 2 Patented Apr. 22, 1941 UNITED STATES PATENT OFFICE ELECTRON DISCHARGE TUBE Application March 22, 1938, Serial No. 197,473 In Germany April 1, 1937 8 Claims.

This invention relates to a method of making electron discharge tubes possessing electrodes which are subjected to surface-forming processes in vacuo. More particularly, such tubes contain electrodes sensitized to photo-emission and electrodes sensitized to secondary emission. Such tubes are generally used for picture analysis in television systems.

As the process of forming a surface for maximum photoemission differs somewhat from the process for obtaining maximum secondary emission, it is desirable to form the two types of surfaces separately and independently of each other.

This invention provides a method of manufacturing such tubes in which each electrode, or each system of electrodes, respectively, is formed independently of other electrodes or systems. In broad terms, the method according to the invention comprises the steps of placing electrodes to be formed differently in separate receptacles, forming the electrode surfaces in vacuo, combining the separate vacuum receptacles into one unit, and combining the separate evacuated spaces with each other.

A tentative explanation may be given in. connection with several embodiments of the invention. Fig. l is a schematic drawing of a pictureanalyzing tube possessing an electrical shutter and an electron-multiplying system, as is shown in Fig. 2. Fig. 3 shows a portion of the device shown in Figs. 1 and 2 immediately before the step of fusing two separate vacuum receptacles together. Fig. 4 shows a further embodiment, namely, a tube, in which an electron stream is modulated by deflection across an aperture and then subjected to electron manipulation.

In Fig. 1 vacuum receptacle l contains, at the left end, a photocathode 2 upon which an optical image is projected by means of lens 3. At the point 4 a glass tube 5 is sealed to the vacuum receptacle I. Glass tube 5 possesses one open end which extends beyond the boundaries of vacuum receptacle I. Thus, an airtight space inside vacuum receptacle I is obtained which can be evacuated through the pump seal 6.

Fig. 2 shows a vacuum receptacle 1, of similar but smaller dimensions than those of tube 5, which is adapted to be rigidly connected with a press 8. Tube I contains an apertured diaphragm 9, a secondary-emissive plate I!) and a plurality of secondary-emissive electrodes H which are permeable to electrons. The apertured diaphragm 9 may later serve as the scanning aperture of an image dissector, as shown in U. S. Patent 1,773,980, issued to P. T. Farnsworth.

Electron multiplication of the current passing through the aperture in diaphragm 9 takes place at the electrodes l0 and II. An anode I2 serves as a collector.

Vacuum receptacles I and I are evacuated independently of each other, and the secondaryemitting electrodes l0 and II, as well as photocathode 2, are also formed independently of each other. The system as shown in Fig. 2 comprising vacuum receptacle 1 and press 8 is then introduced into tube 5, as is shown in Fig. 3. At point l3 press 8 is then sealed to tube 5. A pump seal is provided which allows the evacuation of intermediate space between tubes 5 and 1. After evacuation, this space is sealed off so that a unit is had possessing three separate evacuated spaces. For operation of the tube, these vacuum spaces must be connected with each other. For this purpose, tubes 5 and 1 are each provided with a nipple M of very thin glass. In fusing press 8 to tube 5 care is taken that the nipples of tubes 5 and 1 become located opposite each other. By means of a ring located in the intermediate space between tubes 5 and 1, it is possible to destroy both glass nipples so that all three evacuated spaces become interconnected. It is not believed necessary to discuss the operation of the picture-analyzing tube as this is well known by the above-mentioned patent to P. T. Farnsworth.

The application of this method to the manufacture of a difierent electron discharge tube may be illustrated with the aid of the embodiment as shown in Fig. 4. In Fig. 4, a vacuum receptacle l6 contains a thermionic cathode IT. A defined cross-section of the electron stream emitted by cathode I l is selected by means of an apertured diaphragm [8. An electron image of this cross-section is produced in the plane of diaphragm 22 by means of an electron-optical system, consisting of the electrodes I9, and 2!. The electron image produced in the plane of diaphragm 22 is then defiected by means of deflecting plates 23 and 24 across an aperture in diaphragm 22. The portion of the electron stream passing through the aperture in diaphragm 22 then enters an electron multiplier. This electron multiplier is placed in a separate receptacle and formed separately, as provided for by this invention. A multiplier system as shown in Fig. 2 (however, Without apertured diaphragm I9) is made and introduced into space 25 of vacuum receptacle l6, which is sealed off aside from; the evacuated portion of receptacle Hi. In this case, it is not necessary to fuse a separate tube surrounding the multiplier receptacle into the main vacuum receptacle, as usual, shown in Fig. 1; it suffices merely to provide a separating wall 26. Further steps in the manufacture of the tubes are identical with those described in connection with Fig. 3. In cases where a larger passage between separate vacuum tubes is required, the nipple can be replaced by a thin foil or corresponding area which is destroyed in vacuo in a similar manner.

What I claim is:

1. An electron discharge tube possessing a main vacuum receptacle containing a cathode, a protrusion reaching into the interior of said main vacuum receptacle and extending beyond the boundaries of said main vacuum receptacle, said protrusion having a wall portion inside said main receptacle adapted to be punctured, and a separate vacuum receptacle contaim'ng an anode and adapted to be connected to a press placed in the interior of said protrusion of said main vacuum receptacle, said press being adapted to be fused to the portion of said protrusion extending beyond the boundaries of said main vacuum receptacle, said separate receptacle also having a wall portion adapted to be punctured, said puncturable wall portions being disposed in the path of the electron discharge, thereby to establish an electron discharge path between said cathode and said anode after puncture of said wall portions.

2. An electron discharge tube possessing a main vacuum receptacle containing a cathode, a protrusion reaching into the interior of said main vacuum receptacle and extending beyond the boundaries of said main vacuum receptacle, said protrusion having a wall portion inside said main receptacle adapted to be piuicturedl, and a separate vacuum receptacle containing an electron multiplier structure and adapted to be connected to a press placed in the interior of said protrusion of said main vacuum receptacle, said press being adapted to be fused to the portion of said protrusion extending beyond the boundaries of said main vacuum receptacle, said separate receptacle also having a wall portion adapted to be punctured, said puncturable wall portions being disposed in the path of the electron discharge, thereby to establish an electron discharge path between said cathode and said anode after puncture of said wall portions.

3. An electron discharge envelope comprising a pair of chambers having opposing walls, each of said opposing walls having a weakened protruding portion, and means movable between said opposing walls for simultaneously shattering the weakened portion of each of said opposing walls to effect communication between said chambers.

4. An electron discharge envelope comprising a pair of chambers having opposing walls, each of said opposing walls having a bulge in the direction of the other, and means comprising a ring-like member slidably positioned about one of said chambers for simultaneously shattering the bulged portion of each of said opposing walls to effect communication between said chambers.

5. An electron discharge device comprising a pair of independent chambers, one of said chambers having a photosensitive electrode therein, the other chamber having a secondary-emissive electrode therein, each of said chambers having a weakened wall structure, means supporting said chambers with their weakened wall structures adjacent each other, and means for simultaneously striking said weakened portions to efiect communication between said chambers.

6. An electron discharge device comprising a pair of independent chambers, one of said chambers having a photosensitive electrode therein, the other chamber having a secondary-emissive electrode therein, each of said chambers having a bulge in the direction of the other, means supporting said chambers with their bulged portions adjacent each other, and means for simultaneously striking said bulged portions to effect communication between said chambers.

7. An electron discharge device comprising a first evacuated chamber having a source of electrons at one end thereof and a weakened wall structure at another end thereof, a second evacuated chamber having a plurality of electrodes therein constituting an electron multiplier, said second chamber also having a weakened Wall portion, means supporting said second chamber with its weakened wall portion adjacent the weakened wall portion of said first chamber, and means within said discharge device for simultaneously destroying said weakened wall portions to efiect communication between said chambers.

8. An electron discharge device comprising a first evacuatedchamber having a source of electrons at one end thereof and a wall structure at another end thereof having an outward bulge therein, a second evacuated chamber having a plurality of electrodes therein constituting an electron multiplier, said second chamber also having a bulged wall portion, means supporting said second chamber with its bulged wall portion adjacent the bulged wall portion of said first chamber, and means for simultaneously destroying said bulged wall portions to effect communication between said chambers.

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