US2004790A

US2004790A - Electron discharge device

Info

Publication number: US2004790A
Application number: US670556A
Authority: US
Inventors: Friedrich W Hehlgans
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1932-05-27
Filing date: 1933-05-11
Publication date: 1935-06-11
Anticipated expiration: 1952-06-11
Also published as: NL35720C; GB403876A; FR755917A

Description

June 11', 1935 w. HEHLGANS I 2,004,790

Y ELECTRON DI SC HARGE V DEVICE Filed May 11, 1933 1 Friedrich W Hehlgan's;

His Attor-neg.

a to thecontrol electrodeor Wehne'lt cylinder of a cathode-ray tube, as usedpfor sound. recording,

Patented June 11, 1935 i H ehlg ans, Berlin-Hermsdorf, Ger- 'many,jassignor to GeneralElectric Company, a

corporation of New York I fln lication May 11,1933,"SerialNo."670,556

- The invention relates :to neared n discharge devices, suchas cathode-raytubes,- employed for the purposes-of sound recording, televisionyetc;

An object or the present invention is to provide f a circuit arrangement and apparatus for increas ing by regenerative action, the electrical impulses i applied to the cathode-.rayt'ube whereby the light output and control of the tubeare enhanced.

The invention is ,based on thefollowing p1in-- ciple: If alternating :current voltagesare applied and a telephone receiveris connected in the anode circuit of the tube, electric impulses of considerable strength arefound :to exist inthe anode circuit; These impulsesrepresent a faithfulreproduction, in amplifiediorm, of the voltages applied to the control cylinder; I i i I I, In accordance with .thepresent invention; this principle is employed for increasing the-light output of the cathoderay tube in suchxa manner that theoscillations occurring in the anode cir-' cuit of the tube are appliedtothe control circuit of. the tube in such phase as toradd'to the original alternating current voltage. 'I'heinventi'on Will be better understood when reierenceflis made to thefollowing description and. the accompany-- ing drawing in which Fig.1 shows diagrammati c'ally'a, system embodyingthe invention and-Fig. 2

illustrates an alternative arrangement a In Fig. 1, numeral l designates a: microphone transmitter connectedin'serieswith an ei'iergiz'ing battery 2 ,andthe primary ofgatraLnsformert. The secondaryiwoi the. transformer is connected to theinput circuit of a thermionic amplifier 4 of ordinary construction; amplifier includes an electrostatic control member 5, a filamentary cathode 6 and an anode I. The filament and the anode are connected to difierent potential taps on a common battery 8 or other source of potential. The control member 5 is connected to the negative end of the battery in such a manner as to obtain a constant negative bias.

The output circuit of the amplifier 4 is connected to the control circuit of a cathode-ray tube 9 by means of a well-known capacity and resistance coupling consisting of a capacitor 1' and resistances II and I2. If desired, an inductive or transformer coupling may beused.

The cathode-ray tube is of ordinary type and includes a cathode IS, a control electrode or Wehnelt cylinder 14 and an anode l5 in the form A 01' a circular plate of metal provided with a central aperture It for the cathode rays. At the end of the envelope, opposite from the cathode, there rmlnGermanyi May 2?, 1932 r r m ns (0 173-4 0 is a screen I! of well-known form which fluoresceswhen struck by electrons and the light therefrom isradiated onto a movingfilm 18. The cathode 13, "control member I4 and 'the anode iii of the c'athoderay tubeare connected to various potentialtaps on the common battery 8. Asin the case of'the amplifier" 4, the control member of the resistance [9.

The purpose of the cathode r'ay tube is to translate the electricalundulations applied to the cylinder 14 into light images Which are photographical-1yreproduced-on the sound'recordl8.

1 -Inacc0rdance with my invention, a regenerative circuit isprovided between the anodeand control electrode circuits of the cathode-ray tube orderto increase the control exercised by the cylinder M'on the electron beam striking the fluorescent'screen-H; increased control of the intensity of the light spotand of the photographic image on the soundtrack l8'is obtained.

As shown in Fig. Lthis regenerative effect is produced bymeansof a back-coupling through a conductor 20 connected to a point in-the'anode circuit between the anode 15* and the resistance l9. This conductor has in series therewitha capacitor 2}, fixed or adjustable, also a resistance 22: whichis connected to a point between the secondary winding of the transformer: Send an adjustable resistance 23 inserted in the control circuit of the amplifier 4. The relative magnitude of the

resistances

22 and 23 determines the voltageincrement which is applied to the input of the amplifier 4 and hence, provides an adjustment of the increased voltage impressed on the control member of the cathode-ray tube. It is apparent that by reason of the introduction of the amplifier between the source of voltage variations and the control member of the cathoderay tube the energy fed back in this manner is in the proper voltage phase relation with respect to the voltages applied to the amplifier 4 so that an amplification of these voltages and therefore electrode may be formed for example as a grid,

additional amplifier 4. In this case, an additional electrode may be arranged between the cathode and the Wehnelt cylinder of the cathode-ray tube and the regenerative voltage taken from the circuit which includes this auxiliary electrode. The

or plate with a central opening and is positively charged. Fig. 2 shows such 'a system. v L V As illustrated in Fig. 2, the microphone transmitter l is connected in the local circuit and pro:

ment or Wehnelt cylinder I4 and=thecathode 13 on their way to the fluorescent screen I I.

Between the cathode andtheicontrol cylinder,

there is an electrode 24 having a central aperture 25 in line with the opening in the cylinder 4, and the aperture IS in the anode Hi. The electrode 24 is connected through the current-limiting resistance 26 to an intermediate positive terminal on'the common battery or source ofenergy supply 8. A regenerative coupling is connected between the electrode M and the inputcircuit 0f the cathode-ray tube through a capacitor 2| and resistance 22. It is apparent that instead of the capacitor 2|, an inductive coupling may be used but the capacity coupling is preferred since it is more free from resonance efiects, and selfexcitation within the cathode-ray tubeis thereby avoided. However, if the capacitor 2 l 1 is replacedby an inductive coupling, the production of selfsustained oscillations may be substantially reduced by a Proper adjustment of the

resistances

22, 23 and the proper choice of the: voltages employed in the system. y a

'What I claim as new and desire to-secure by Letters Patent of the United States, is:,

1. In combination, a cathode-ray tube for translating electrical impulses into light rays, said tube including a cathode, an anode, an electrostatic control member and a screen adapted to fluoresce' when struck by electrons, energy supply circuits for. the electrodes, a source" ofyelectrical impulses connected to said control member, and means for transferring electrical energy from the anode of said tube to the control member, said meansincluding an electrical coupling vbetween said anode and control member, whereby control of the electrons through the tube and the variations in intensity of the light spot' on the fluorescent screen are enhanced.

,2. In combination, a cathode-ray tube for translating electrical impulses into light rays, said tube including a cathode, an anodaan electrostatic control member and a screen adapted to fluoresce when struck by electrons, energy supply circuits for the electrodes,-a source of electrical impulses, an amplifier having input and output circuits,'said input circuit being connected to said source of impulses, said output circuit being connected to said control member, and an electrical. energy v; feedback connection ;between said anode an'dthe input circuit of'said ampli- .fier for increasing the control exercised on the duces voltage variations between the control eleelectron stream in the cathode-ray tube by said control member and for enhancing'the variations in the intensity ,of the luminous spot produced on the screen by electrons; I

3. In combination, a cathode-ray tube for translating electrical impulses into light rays,

said tubeinoluding a cathode, an anode, an electrostatic control member and a screen adapted to fluoresce when struck by electrons, energy supply circuits for the electrodes, a source of electrical impulses', an amplifier having input and output circuits, said input circuit being connected to said source of'impulses, said' output circuit being connected .to said control member, and an electrical energy feedback connection between said anode and the input circuit of said amplifier, said connection includinga capacitor.

4. In' combination, a cathode-ray tube 'for translating electrical impulses into light rays, said tube including a cathode, an anode, an electrostatic control member,ienergy supply circuits for the electrodes, said tube also containing a screen which fluoresces when struck byelectrons and an electrode positioned between said control member and the cathode and adapted to be charged positive with respect to the cathode, and an electrical energy feedback connection between said positively charged electrode'and said control memberxwhereby. the.'control of the position and the variations in intensity of. the luminous spotproduced on the screen by electrons are enhanced. I

5.-In combination, a cathode-ray tube for translating electrical impulses "into light rays,

said tube including a cathode, an anode, an'electrostatic control member, energy supply circuits for the. electrodes, said' tube also containing a screen which fluoresces when struck by electrons FRIEDRICH W. HEHLGANS.