Патент USA US2108617код для вставки
Few-5., 15, was° 2168517 F. SCHRC'JTER ELECTRON TUBE Filed July 14, 1934 INVENTOR FRITZ SCH/ZOTER BY 7%. ZWW ATTORNEY Patented Feb. 15, 1938 2,108,617 UNITED STATES PATENT OFFICE 2,108,617 ELECTRON TUBE Fritz Schriiter, Berlin, Germany, assignor to Tclefunken Gesellschaft fiir Drahtlose Tele graphic in. b. 11., Berlin, Germany, a corpora tion of Germany Application July 14, 1934, Serial No. 735,203 In Germany July 28, 1933 5 Claims. (Cl. 250-275) In gas contained Braun tubes serving as tele vision scanning means or as television picture the focusing cathode 5. Positioned adjacent to receiver, the so-called ion cross caused by the the cathode is a heat dissociable halogen com neutral zone of the electrostatical deviation ?elds pound ‘! so that upon the heating of the ther 5 (zero point anomaly) causes disturbance. For mionic cathode, the compound dissociates to produce electron negative ions. 5 on the one hand, the ion space charge effect pro Besides the electro-negative gases or vapors duces a ?eld distortion between thev deviation plates which reduces the deviation velocity of the which are required in an extremely low concen electron ray in the zero zone, thus also causing tration only, the inert ?lling gases such as argon, neon or helium ordinarily used in Braun tubes 10 a distortion of the picture. In addition, the slower movement of the electron ray produces on are suitably present, they are even necessary un~ 10 der certain circumstances, since without their the receiving screen an increased brilliancy dis cernible as a brighter cross standing out from the presence the desired concentration action hold background. 15 2O ‘ The invention has for its purpose to avoid this disturbing phenomenon. It consists in the com pensation of the space charge produced in the zero zone by the positive ions, by a corresponding ly apportioned space charge of negative gas or vapor ions. In accordance therewith electro negative gases or vapors, for instance iodine vapor or vapor of metallic or non-metallic halogen compounds are provided in the Braun tube. The heavy negative ions which may then be produced in a small amount by adhesion of electrons onto -5 the gas or vapor particles, and which due to their inertia of the mass have approximately the same electrical movability as the positive ions remain mixed with the latter and compensate the otherwise forming disturbing space charge 3 eiiect. In carrying out the invention it is of advantage to employ in the tube such compounds of electro-negative elements which at a de?nite temperature, for instance in the vicinity of the heated cathode, begin to dissociate, such as zircon chloride, thallithallo-chlo-ride and the like. In selecting the respective substance not only must its capability of producing suitable vapors at the desired pressure be considered, but also its chem 40 ical behaviour with respect to metallic electrodes of the tube and in particular with respect to the cathode whose function during the entire dura 3 tion of action should be in?uenced as little as possible. 45 In the drawing I have shown schematically one embodiment of my invention. . Referring to the drawing, the envelope 1 has mounted within it the thermionic‘ cathode 3 and ing the electron ray together, would be absent. Having thus described the invention, what I claim is: 15 1. In a cathode ray tube wherein is provided a cathode, the method of supplying an electro negative vapor comprising the steps of position ing a heat-dissociable halogen compound adja cent to the cathode and supplying heat to said cathode to produce dissociation of said compound. 20 2. In a cathode ray tube wherein is provided a cathode, the method of supplying an electro negative vapor comprising the steps of position ing zircon chloride adjacent to the cathode and supplying heat to said cathode to produce dis- 25 sociation of said compound. 3. In a cathode ray tube wherein is provided a cathode; the method of supply electro-negative vapor comprising the steps of positioning thalli thallo chloride adjacent to the cathode, and sup- 3° plying heat to said cathode to produce dissocia tion of the compound. 4. An electron device comprising a glass en velope, a thermionic cathode within said envelope for emitting electrons, electron focusing means 35 cooperating with said cathode, and a heat dis sociable halogen compound adjacent to said cathode. 5. An electron device comprising a glass en velope, a thermionic cathode within said envelope ‘10 for emitting electrons, electron focusing means cooperating with said cathode, a heat dissociable halogen compound adjacent to said cathode, and a gas chosen from Group VIII of the Periodic Series under low pressure ?lling said envelope. FRITZ scHRc'iTER.