US2100701A - Braun tube - Google Patents

Braun tube Download PDF

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Publication number
US2100701A
US2100701A US694134A US69413433A US2100701A US 2100701 A US2100701 A US 2100701A US 694134 A US694134 A US 694134A US 69413433 A US69413433 A US 69413433A US 2100701 A US2100701 A US 2100701A
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United States
Prior art keywords
cathode
emissive
optical system
tube
respect
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Expired - Lifetime
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US694134A
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English (en)
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Schlesinger Kurt
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Individual
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Individual
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/48—Electron guns
    • H01J29/485—Construction of the gun or of parts thereof

Definitions

  • lateral pull defect means a nondesired efiect produced by the control electrode, which consists in that each change in the control voltage causes not only the desired change in the intensity. of the cathode ray but simultaneously a non-desired change in the direction of the cathode ray which results in a non-desired displacement of thespot on the fluorescent screen.
  • the emissive coating is embodied and arranged symmetrically on the cathode in relation to the axis of the tube, in such fashion that the normal on all lines connecting. eachtwo corresponding points of the curve bounding the emissive layer coincides with the axis of the tube. At. the same time the size of the'emissive coating is such that the emission of all emissive points is covered by the electron optic.
  • -electronoptic means one electronoptical system or a plurality of electron-optical systems which are provided in the .tube for the purpose of producing ,on the picture receiving screen an ,imagepoint representing a sharppicture eitherof the cathode itself or of a suitable aperture which is arranged between the cathode and the electron-optical system and acts asthe proper cathode of the tube.
  • the electron-optical system of television tubes which may consist, for example, of Wehnelt cylinder, preliminary or screening anode, second cylinder and after-acceleration anode, the preliminary anode being positive in relation to the Wehnelt cylinder, the second cylinder weakly negative in relation to the screening anode, and :he after-acceleration anode possesses the highest positive potential occurring-possesses in practice a relatively small aperture of, for example, approximately 10", i. e., it is not able to Berlin, Germany 1933, Serial No. 694,134 ctober 21, 1932 concentrate rays which form with the system axis an angle of more than 10.
  • the emissive coating is embodied in such fashion that none of the output normals possesses in relation to the axis of the tube an inclination which is greater than the aperture of the electron-optical system employed.
  • level 0 means the curved plane connecting all of the points in the vicinity of the cathode, the potential of which is zero.
  • the position and the curvature of this plane is defined by the potentials of the cathode and of the control electrode and by the arrangement of these electrodes with respect to one another and to the anode.
  • the position and curvature of the lever 0 changes in correspondence with the changes of the control potential applied to the control electrode in such a way, that it moves the more in the direction to the cathode surface the more positive the control electrode becomes, until at last it coincides with the emissive surface.
  • FIG. 1 is a section through the complete cathode arrangement.
  • Fig. 2 is a plan view of the same arrangement, whilst in Fig. 3 there is shown a particular form of embodiment of the cathode member, and in Fig. 4 a plan view of this member.
  • Fig. 5 is a diagrammatic sectional elevation of a cathode ray tube comprising a cathode arrangement according to the invention.
  • the tube 5 carries at its upper end pro ecting out of the for the heating current and carries the metallic, preferably nickelcathode member 3.
  • the sleevelike cathode member 3 is made in the form of a hollow reflector at its upper, preferably widened end, the centre of curvature being disposed on
  • the emissive substance for example an alkaline earth oxide or a mixture of alkaline earth metal oxides and alkaline earth metals, may be applied to the surface of the hollow reflector by painting or the like. It has been found, however, that in this manner exact confinement of the emissive surface is not to be obtained.
  • the surface in the hollow reflector intended for reception of the emissive substance is engraving, milling or the like, and the recess formed in this fashion is filled out with the emissive substance.
  • the surface may again be polished, so that the emissive substance itself forms part of the hollow reflector, and is contained solely in the recesses provided for the same, which recesses possess an exactly pre-determined form. In this manner it is possible to give the emissive surface an exactly defined piedetermined shape.
  • an elongated slot which may possess, for example, the dimensions of .5-1 mm. in Width and 2-3 mm. in length, and the greatest extension of which is disposed vertically to the line direction.
  • cathodes of this nature it is possible to produce points of corresponding rod-like form, which for the first time permitof the production of a line screen, the single lines of which are disposed in close proximity to one another without intermediate spacings.
  • a cathode of this type is illustrated in Figs. 3 and 4.
  • the emissive substance is provided in the preliminarily engraved or milled slot II, in such fashion that the emissive surface possesses the requisite curvature according to the invention, and that no additional emissive centres of any kind are present outside of this emissive surface.
  • the emissive substance is represented as grain point I I.
  • the embodiment of the cathode with the massive metallic cathode body 3 according to the invention prevents in reliable fashion a variation in the form of the emissive surface upon the assembly. Owing to the fact that thicker emissive coatings-which represent a greater reserveare employed, a partial burning out of the emissive surface and accordingly a variation in the effective surface in operation will be safely avoided for a period of several thousand hours.
  • Fig. 5 the following additional references are used: l3 for the second cylinder, l4 for the after-acceleration anode, and I5 for the envelope 'of the cathode ray tube.
  • cathode member 3 also in other fashion.
  • the essential this cathode body be of such a. stable kind that it cannot be distorted either upon the assembly or in operation or otherwise vary its form.
  • the concentration effect which is capable of being obtained with the assistance of the cathode arrangement according to the invention is so considerable that it is possible, particularly when employing the Braun tube for osciliographic purposes, to dispense with Wehnelt cylinder, or to link up the Wehnelt cylinder with zero potential and employ the same solely as light screen.
  • a structural unit producing a bundle of cathode rays, the angle of inclination of which with respect to the tube axis does not exceed 10 degrees for the purpose of causing the electron optical system to collect all of the electrons produced by said unit for forming one sharp image on the image screen, said structural unit comprising an indirectly heated cathode body, a highly emissive surface covering a partial area of the surface of the cathode body facing the electron optical system, said structural unit further comprising a control electrode, said highly emissive surface being disposed symmetrically with respect to said control electrode.
  • highly emissive layer disposed in a recess occupystructural unit further comprising a control elec trode, said highly emissive surface being disposed symmetrically trode.
  • a structural unit producing a bundle of cathode rays, the angle of inclination of which with respect to the tube axis does not exceed 10 degrees for the purpose of causing the electron optical system to collect all of the electrons produced by said unit for forming one sharp image on the image screen, said structural unit comprising an indirectly heated cathode body, the surface of said cathode body facing the electron optical system being curved, a highly emissive surface covering a partial area of the surface of the cathode body facing the electron optical system, said structural unit further comprising a control electrode, said highly emissive surface being disposed symmetrically with respect.
  • said unit for forming one body, a highly emissive layer of at least millisharp image onthe image screen, said structural metre thickness disposed in a recess occupying unit comprising an indirectly heated cathode a partial area of the surface of the cathode body body, a highly emissive surface covering a partial facing the electron optical system, said structural area of the surface of the cathode body facing unit further comprising a control electrode, said the electron optical system, said structural unit highly emissive surface being disposed symfurther comprising a control cylinder, a metallic metrically with respect to said control electrode. cathode holder tightly fitting into said control 5.
  • a Braun tube in combination with a piccylinder, said cathode body being mounted on ture receiving screen and an electro-static elecand insulated from said cathode holder, said tron optical system having an aperture angle of at highly emissive surface being disposed symmetrileast 10 degrees: a structural unit producing a cally with respect to said control electrode. bundle of cathode rays, the angle of inclination of 7.
  • An indirectly heated cathode comprising a which with respect to the tube axis does not exheater element, an equipotential bodymounted ceed 10 degrees for the purpose of causing the near said heater element, part of said equipotenelectron optical system to collect all of the electial body being a mirror surface hollow member, trons produced by said unit for forming one the surface of the hollow member having a recess, sharp image on the image screen, said structural and a highly emissive substance disposed in said unit comprising an indirectly heated body, the recess. surface of said cathode body facing the electron 8.
  • An indirectly heated cathode comprising a optical system being curved, a highly emissive heater element, an equipotential body mounted layer disposed in a recess occupying a partial near said heater element, part of said equipotenarea of the surface of the cathode body facing tial body being a mirror surface hollow member, the electron optical system, said structural unit the surface of the hollow member having a refurther comprising a control electrode, said highly cess, and a highly emissive substance disposed in emissive surface being disposed symmetrically said recess, the surface of the emissive subtance with respect to said control electrode. forming together with the non-emissive parts of 6. In a Braun tube in combination with a picthe hollow member a uniform concave surface. ture receiving screen and an electro-static elec- KURT SCHLESINGER.

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  • Electrodes For Cathode-Ray Tubes (AREA)
  • Solid Thermionic Cathode (AREA)
US694134A 1932-10-21 1933-10-18 Braun tube Expired - Lifetime US2100701A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE431774X 1932-10-21

Publications (1)

Publication Number Publication Date
US2100701A true US2100701A (en) 1937-11-30

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US694134A Expired - Lifetime US2100701A (en) 1932-10-21 1933-10-18 Braun tube

Country Status (4)

Country Link
US (1) US2100701A (en, 2012)
FR (1) FR762649A (en, 2012)
GB (1) GB431774A (en, 2012)
NL (2) NL46608C (en, 2012)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2490308A (en) * 1944-09-30 1949-12-06 Emi Ltd Electron lens system
US2518472A (en) * 1949-02-03 1950-08-15 Heil Oskar Electron gun
US2570208A (en) * 1939-08-21 1951-10-09 Int Standard Electric Corp Electronic switch
US2573287A (en) * 1950-06-23 1951-10-30 Rauland Corp Electron gun for cathode-ray tubes
US2616038A (en) * 1947-09-23 1952-10-28 Univ Leland Stanford Junior Frequency converter

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2570208A (en) * 1939-08-21 1951-10-09 Int Standard Electric Corp Electronic switch
US2490308A (en) * 1944-09-30 1949-12-06 Emi Ltd Electron lens system
US2616038A (en) * 1947-09-23 1952-10-28 Univ Leland Stanford Junior Frequency converter
US2518472A (en) * 1949-02-03 1950-08-15 Heil Oskar Electron gun
US2573287A (en) * 1950-06-23 1951-10-30 Rauland Corp Electron gun for cathode-ray tubes

Also Published As

Publication number Publication date
NL46608C (en, 2012)
FR762649A (fr) 1934-04-14
GB431774A (en) 1935-07-16
NL39573C (en, 2012)

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