US2261645A - Protective system - Google Patents

Protective system Download PDF

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Publication number
US2261645A
US2261645A US321065A US32106540A US2261645A US 2261645 A US2261645 A US 2261645A US 321065 A US321065 A US 321065A US 32106540 A US32106540 A US 32106540A US 2261645 A US2261645 A US 2261645A
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Prior art keywords
cathode
ray
anode
deflecting
discharge
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Expired - Lifetime
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US321065A
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English (en)
Inventor
Jean L Delvaux
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General Electric Co
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General Electric Co
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Publication date
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
    • H04N3/10—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical
    • H04N3/16—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by deflecting electron beam in cathode-ray tube, e.g. scanning corrections
    • H04N3/20—Prevention of damage to cathode-ray tubes in the event of failure of scanning

Definitions

  • Qh ms- My invention relates to protective systems for electron discharge devices, and more particularly to systems for the protection of devices of the cathode-ray type.
  • a-more or less concentrated electron beam is directed against a sensitivevsurface comprising ascreen, mosaic, fluorescent coating, or the like.
  • a sensitivevsurface comprising ascreen, mosaic, fluorescent coating, or the like.
  • suitable scanning or ray-deflecting circuits the beam is caused to traverse the sensitive, surface periodically.
  • Such devices have wide application, for example in oscilloscopes, oscillographs, television transmitters, and television receivers.
  • one such protece tive system heretofore employed comprises one or more thermionic devices with associated input and output circuits. Potentials derived from the ray-deflecting circuits and applied to the input circuits control the flow of current through the 1 actuating coil, or coils, of one or more electromagnetic relays included in the output circuits. The relay,'or relays, in turn control the energization and deenergization of a power supply trans.-
  • FIG. 1 diagrammatically illustrates one embodiment of my invention
  • Fig. 2 is a fragmentary diagrammatic representation of a modification of a portion of the circuit of Fig. 1.
  • an electron discharge device'l is illustrated in this particular embodiment as being a cathode-ray tube of conventional design.
  • the discharge device illustrated is particularly adapted for television receiver circuits, though it will be understood that it may take various forms.
  • the device I comprises a cathode 2, a control grid 3 and a main anode 4.
  • Electrons emitted by the cathode 2 are directed in a more or less concentrated stream against the end of the tube envelope, the inner surface of which is provided with a fluorescent screen or coating 5.
  • a positive potential is impressed upon the anode 4 by the direct
  • the potentiometer I2 provides a means for varying the average potential of the grid 3 with respect to the cathode 2, which in a television receiver permits adjustment of the average brightness of the image formed on the surface 5 as is well known in the art.
  • the thermionic devices I6 and I! are illustrated as diodes having directly heated cathodes 8. nd I9 and no e 20 and 2 es c ive y. These diodes are connected in series between the cathode 2 and the conductor I5; The centertapped resistors 22 and 23 provide means for makboth a wi s or an a on and. method 9f QB???" ing "connection to eagh cathode circuit at a Point of average cathode potential, in the conventional manner.
  • ray-deflection sources 24 and 25 On either side of the discharge device I are shown ray-deflection sources 24 and 25. Potentials supplied from these sources through two pairs of deflecting coils 26 and 21 respectively cause the electron beam to traverse the surface 5 according to a predetermined pattern in a Wellknown manner. For example, in a television receiver these sources may provide the vertical and horizontal scanning potentials. While the deflecting means have been illustrated as of the electromagnetic type, it will of course be understood that they may be of the electrostatic type or a combination of the two types.
  • resistors 28 and 29 are connected between the pairs of coils 25 and 21 respectively.
  • the resistor 28 is connected in circuit with the cathode 19 through the conductors 30 and the resistor 29 is similarly connected in circuit with the cathode l8 through the conductors 3
  • flow of current in either ray-deflecting circuit causes a potential to be developed across the resistor included therein, in turn providing a flow of heating current through the cathode connected in circuit with that resistor.
  • resistor 22 is in parallel with the resistor 29, it will be obvious that these resistors may be combined. The same is also true of the resistors 23 and 28.
  • connection between the cathode 2 and the negative terminal of the direct current source 8 through the conductor 32 and capacitor 33 provides a by-pass for the alternating components of the anode-cathode current.
  • a high resistance 34 preferably having a resistance of several megohms, is connected between conductors 32 and to protect the cathode against overvoltage.
  • Fig. 2 A modification of this portion of the circuit is illustrated in Fig. 2. This corresponds in all respects to Fig. 1, excepting that the resistors 22, 23, 28 and 29 have been replaced by the filament transformers 35 and 36. The secondaries of these transformers are also provided with center taps for connections at points of average cathode potential in the usual manner.
  • the heating currents through the cathodes I8 and I9 substantially independent of normal fluctuations in the ray-deflection potentials.
  • known regulating devices may be employed in the filament circuits; for example, non-linear resistances, or resistances with a negative characteristic.
  • the diodes l6 and I! should also be chosen for low current consumption, low thermal inertia and low anode to cathode voltage drop.
  • the cathode 2 of the device I may be supplied with heating current derived from a ray-deflection circuit, or other control circuit, exactly as described for the diodes l6 and IT; or if the cathode 2 is of the indirectlyheated type, the heating filament may be insulated from the cathode 2 and energized in the same manner.
  • protective devices l6 and I! have been illustrated as diodes of the directly heated type, it is obvious that they may be of the indirectly heated type, or that they may have more than two electrodes. They may be mounted within a common tube envelope or even within the envelope of the tube I itself.
  • an electron discharge device a thermionic device having an anode and electrically heated cathode, connections for applying potential to said discharge device for developing an electron discharge therein, said connections including the anode to cathode path of said thermionic device, control means for directly influencing said discharge, means for energizing said control means, and means for supplying current for heating said cathode in response to energization of said control means, whereby said discharge can be developed onlv when said control means is energized.
  • an electron discharge device having an anode and a cathode
  • a thermionic device having an anode and an electrically heated cathode
  • means for developing an electron discharge in said discharge device comprising in series circuit relation a source of potential and the anode to cathode paths of said devices, control means for directly influencing said discharge, means for energizing said control means, and means for supplying heating current to said electrically heated cathode in response to energization of said control means, whereby said discharge can be developed only when said control means is energized.
  • an electron discharge device of the cathode ray type a thermionic device having an anode and an electrically heated cathode, connections for applying potential to said discharge device for developing a cathode ray therein, said connections including the anode to cathode path of said thermionic device, means for deflecting said cathode ray, means for energizing said ray deflecting means, and means for supplying current for heating said cathode in response to energization of said flecting saidcathode ray, means for energizing said ray-deflecting means, and means for supplying heating current to said electrically heated cathode in response to energization of i I said ray-deflecting means,whereby said cathode ray can be developed only when said ray deflecting means is energized.
  • a cathode ray device having means to develop a cathode ray discharge therein
  • thermionic device having an electrically heated cathode, a source of unidirectional potential, circuit connections including in series circuit relation said devices and said source, means for deflecting said ray discharge, and means for deriving current for heating said cathode from said ray deflecting means.
  • a cathode ray discharge device having a sensitive surface therein to be protected, means within said device for producing a cathode ray and an anode for accelerating said ray toward said surface, a thermionic device having an electrically, heated cathode, means for applying a positive potential to said anode through the space discharge path of said thermionic device, meansfor deflecting said ray,
  • a protective system the combination with a cathode ray discharge device having a sensitive surface therein to be protected, a cathode within said device for producing a cath 'ode ray and an anode 'for accelerating said ray response to energization of said ray deflectingmeans, whereby said thermionic device is rendered non-conducting and said discharge device inoperative upon deenergization of said ray deflecting means.
  • a source of unidirectional potential connections for impressing said potential between the anode and cathode of said discharge device for developing a cathode ray discharge therein, said connections including the anode to cathode path of said thermionic device, means for deflecting said cathode ray comprising a deflecting coil, a fluctuating source of potential for energizing said ray deflecting means, and means for supplying heating current to said filamentary cathode in response to energization of said ray deflecting means, whereby said thermionic device is rendered non-conducting and said discharge device inoperative upon deenergization of said ray deflecting means.
  • a cathode ray discharge device having an electron emissive cathode, an anode and a sensitive surface
  • a thermionic device having an anode and a filamentary cathode
  • connections for impressing said potential between the anode and cathode of said discharge device for developing a cathode ray discharge therein said connections including the anode to cathode path of said thermionic device, means for deflecting said cathode ray comprising a deflecting coil, a source of deflecting potentials, and an impedance connected in series, and means for connecting the filamentary cathode of said thermionic device across said impedance for supplying heating current thereto from said deflecting source, whereby said thermionic device is rendered non-conducting upon failure of said deflecting coil or said deflecting source and application of potential to 7 said discharge device is thereby prevented.
  • a cathode ray discharge device having an electron emissive cathode, an anode and a sensitive surface, a plurality of thermionic devices each having an anode and an electrically heated cathode, connections forimpressing a potential between the anode and cathode of said discharge device to produce a cathode ray discharge therein, said connections including the anode to cathode paths of all said thermionic devices in series, a plurality of means for deflecting said discharge, and means for deriving the cathode heating current for each of said thermionic devices from a different one of said deflecting means.
  • a cathode ray discharge device having an electron emissive cathode, an anode and a sensitive surface to be protected, of a plurality of thermionic devices each having an anode and a filamentary cathode, a source of unidirectional potential, connections for impressing said potential between the anode and cathode ofsaid discharge device to produce a cathode ray discharge therein, said connections including the anode to cathode paths of all said thermionic devices in series, a plurality of ray deflecting means for deflecting said discharge, and means for supplying heating current to the filamentary cathode of each thermionic device in response to the energization of a different one of said ray deflecting means, whereby each thermionic device is rendered non-conducting upon deenergization of the corresponding ray deflecting means and whereby said discharge device is rendered inoperative upon deenergization of any one of said

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US321065A 1939-05-11 1940-02-27 Protective system Expired - Lifetime US2261645A (en)

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FR859345T 1939-05-11

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BE (1) BE438554A (xx)
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Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2425491A (en) * 1943-06-22 1947-08-12 Rca Corp Deflection circuit
US2441732A (en) * 1945-03-28 1948-05-18 Rca Corp Cathode heater supply from cathode-ray deflecting circuit
US2444902A (en) * 1946-02-27 1948-07-06 Rca Corp Protective circuit
US2514079A (en) * 1948-10-26 1950-07-04 Rca Corp Power supply interlock system
US2567861A (en) * 1946-01-07 1951-09-11 Robert M Silliman Cathode-ray beam intensity control
US2577848A (en) * 1950-02-16 1951-12-11 Rca Corp Protective circuit
US2584932A (en) * 1949-07-16 1952-02-05 Rca Corp Television kinescope projection circuit
US2625265A (en) * 1947-04-01 1953-01-13 Electric Sorting Machine Compa Photoelectric sorting apparatus
US2694784A (en) * 1951-02-02 1954-11-16 Int Standard Electric Corp Anode voltage supply for television receivers
US2709768A (en) * 1952-06-05 1955-05-31 Gen Precision Lab Inc Cathode ray tube protection circuits
US2810858A (en) * 1954-06-14 1957-10-22 Itt Protective circuit
US2846616A (en) * 1954-12-08 1958-08-05 Philips Corp Circuit-arrangement protecting the cathode-ray tube of television receivers
US2980904A (en) * 1942-06-08 1961-04-18 Gen Electric Cathode ray apparatus

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2980904A (en) * 1942-06-08 1961-04-18 Gen Electric Cathode ray apparatus
US2425491A (en) * 1943-06-22 1947-08-12 Rca Corp Deflection circuit
US2441732A (en) * 1945-03-28 1948-05-18 Rca Corp Cathode heater supply from cathode-ray deflecting circuit
US2567861A (en) * 1946-01-07 1951-09-11 Robert M Silliman Cathode-ray beam intensity control
US2444902A (en) * 1946-02-27 1948-07-06 Rca Corp Protective circuit
US2625265A (en) * 1947-04-01 1953-01-13 Electric Sorting Machine Compa Photoelectric sorting apparatus
US2514079A (en) * 1948-10-26 1950-07-04 Rca Corp Power supply interlock system
US2584932A (en) * 1949-07-16 1952-02-05 Rca Corp Television kinescope projection circuit
US2577848A (en) * 1950-02-16 1951-12-11 Rca Corp Protective circuit
US2694784A (en) * 1951-02-02 1954-11-16 Int Standard Electric Corp Anode voltage supply for television receivers
US2709768A (en) * 1952-06-05 1955-05-31 Gen Precision Lab Inc Cathode ray tube protection circuits
US2810858A (en) * 1954-06-14 1957-10-22 Itt Protective circuit
US2846616A (en) * 1954-12-08 1958-08-05 Philips Corp Circuit-arrangement protecting the cathode-ray tube of television receivers

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Publication number Publication date
FR859345A (fr) 1940-12-16
BE438554A (xx)

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