US2147760A - Television apparatus - Google Patents

Television apparatus Download PDF

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Publication number
US2147760A
US2147760A US727228A US72722834A US2147760A US 2147760 A US2147760 A US 2147760A US 727228 A US727228 A US 727228A US 72722834 A US72722834 A US 72722834A US 2147760 A US2147760 A US 2147760A
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US
United States
Prior art keywords
mosaic
electrons
anode
cathode
photo
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US727228A
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English (en)
Inventor
Arthur W Vance
Branson Harry
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
RCA Corp
Original Assignee
RCA Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by RCA Corp filed Critical RCA Corp
Priority to US727228A priority Critical patent/US2147760A/en
Priority to FR790257D priority patent/FR790257A/fr
Priority to NL73637A priority patent/NL44769C/xx
Priority to DE1935R0093420 priority patent/DE699657C/de
Priority to GB15170/35A priority patent/GB434942A/en
Application granted granted Critical
Publication of US2147760A publication Critical patent/US2147760A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/26—Image pick-up tubes having an input of visible light and electric output
    • H01J31/28—Image pick-up tubes having an input of visible light and electric output with electron ray scanning the image screen
    • H01J31/30—Image pick-up tubes having an input of visible light and electric output with electron ray scanning the image screen having regulation of screen potential at anode potential, e.g. iconoscope
    • 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
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/021—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof arrangements for eliminating interferences in the tube

Definitions

  • Our invention relates totelevision apparatus and particularly to television transmitter tubes of the cathode-ray type
  • television transmitter tubes of the type de- 5 scribed in an article by Dr. V. K. Zworykin entitled Televislon which appears in the January, 1934, issue of the Journal of the Franklin Institute an image of the picture to be transmitted is formed uponva mosaic of minute light-sensitive elements supported on and insulated from a common metallic back-plate, each element being the cathode of a photo-electric cell.
  • Each of these photo-electric cell cathodes acquires a positive potential having a value which depends upon the 15 intensity of the nght striking it.
  • the mosaic is scanned by a cathode-ray beam whereby picture current appears in an output circuit, the picture current having a value depending upon said positive potentials.
  • main object of our invention is to improve the sensitivity and/or eiliciency of a cathode-ray transmitter tube of the above-mentioned type.
  • an object of our invention is 25 to apply a negative polarizing potential to the cathode of a photo-electric cell unit in atrans mitter tube of the above-mentioned type.
  • the transmitter tube with an auxiliary source of electrons and spray these electrons upon the lightsensitive mosaic.
  • the electrons are projected towards the mosaic at a comparatively low velocitywhereby a negative potential is built up on 35 the photo-electric cell elements or cathodes to produce an increased potential difference or polarizlng voltage between the cathode and anode of each photo-electric cell.
  • the electrons are sprayed upon the 40 mosaic continuously, while in another embodiment the electrons are sprayed thereon only during an interruption in the scanning, as at the end of each horizontal scanning line.
  • FIG. 1 is a view of a television transmitter tube and associated circuit constructed in accordance with one embodiment of our invention
  • Fig. 2 is a view of another embodiment of our invention.
  • Fig. 3 is a schematic diagram of the photo-electric cell circuit of the tube shown in Figs. 1 and 2;
  • Fig. 4 is a set of curves which are referred to in explaining one embodiment of the invention.
  • FIG. 1 our invention is shown applied to a television transmitter tube of the character described in the above-mentioned publica- 5 tion.
  • the tube comprises a highly evacuated envelope I in which is located an electron gun consisting of a cathode 3, a control electrode 5 and a first anode 1.
  • the anode 1 is maintained at a suitable positive potential with respect to the cathode by means of a battery 9 while the control electrode is maintained at a suitable negative potentlalby means of a battery II.
  • the electrons leaving the rst anode 1 are accelerated, and the electron beam focused to the desired small cross-sectional area, by means of a second anode I3 which consists of a metallic coating on the inner surface of the envelope I. 'I'he second anode I3 is connected to ground and maintained at a comparatively high positive potential by means of a battery I5 connected in series with the battery 9.
  • a mosaic I1 of light sensitive elements is supported in the envelope I in such position that it may be scanned by the electron beam. It is also positioned to permit an image of an object to be transmitted to be formed thereon by means of a suitable lens system I9.
  • Deflecting devices such as deecting coils 2I and 23 are provided for deflecting the electron beam in a horizontal plane and in a vertical plane, respectively.
  • Picture signals from the transmitter tube are impressed upon an amplifier 25 through an output resistor 21 which is connected between backplate of the mosaic I1 and ground.
  • a biasing battery 29 is included in the circuit between they resistor 21 and ground for applying a negative bias to the control grid of the amplifier tube 25.
  • 'I'he mosaic I1 which in itself is no part of the 40 present invention, may be constructed in a variety of ways. In a preferred form it consists of a thin sheet of mica having a continuous metallic coatlng on the back side thereof which is electrically connected to the output resistor 21. This metallic coating will be referred to as the signal plate.
  • 'Ihe mosaic proper may consist of a multitude of silver globules each of ⁇ which has a nlm of silver oxide thereon, the silver oxide lm being coated with caesium. In such a mosaic, the light sensitive elements are electrically insulated from each other and from the metallic coating or signal plate on the back of the mica sheet.
  • Another possible method of constructing a mosaic is that side of the mica and separating the light-sensitive material into a large number of elements insulatedfrom each other by ruling the light sensitive/fum with a ruung machine.
  • stili anothermethod-of vmaking a mosaic is to form an exceedinglythin coating of light-sensitivev material upon the mica, the coating not necessarily being discontinuous, but being so thin that the resistance between picture elements is very high,
  • Each light-sensitive element of the mosaic I1 acts as the cathode of a photo-electric cell which has the metallic coating I3 as its anode, the second anode I3 functioning not only as an accelerating and focusing electrode for the electron beam but also as a common photo-electric cell anode for ⁇ the photo-electric cell cathodes in the mosaic.
  • the photo-electric cell circuit of the transmitter tube is shown in Fig. 3 where parts similar to those in Fig. l areindicated by the same reference numerals.
  • Two light-sensitive globules or cathode elements of the mosaic I1 are indicated at 3
  • and 33 is connected through the biasing battery 29 output resistor 21 to the metallic coating indicated at 35 which is on the back side of the mica sheet (not shown).
  • and 33 are connected to the metallic coating or signal plate 35 only through the capacity between the silver ⁇ globules and the said metallic coating. These capacity connections are represented by the condensers 31 and 39.
  • each light sensitive element or globule acquires a positive charge having a value depending upon the intensity of the light striking it.
  • 'I'he positive charge is acquired as a result of the light sensitive element emitting electrons.
  • the condenser which it forms with the signal plate is likewise charged so that each time a light sensitive element is scanned by the electron beam, the condenser is discharged through the output resistor 21.
  • This discharge current which has a value depending upon the intensity of light at a certain picture area, is the picture signal current.
  • the scanning beam brings the mosaic to a certain equilibrium potential each time it scans the mosaic.
  • the mosaic is in condition to repeat the cycle of operation.
  • the anode 45 may consist of a metallic coating on the inner surface of the envelope, this coating being a continuation of the coating I3 which forms the second anode oi the electron gun. It lwill be understood that this entire metallic coating I3 .which forms4 the two anodes functionsas the photo-electric cell anode for the mosaic I1.
  • the cathode 4I and the control electrode 43 are connected through adjustable taps to a potentiometer 41 connected across the battery I5. It will be noted that no attempt is made to direct the electrons leaving the auxiliary cathode 4
  • and the anode 45 is so adjusted that the electrons reach the mosaic I1 at a velocity which is low compared with the velocity of the electron beam
  • the velocity of the electrons sprayed upon the mosaic should be such that the flow of secondary electrons produced by the bombardment of the sprayed electrons is less than the iiow of electrons striking the mosaic.
  • the ratio of secondary electrons to primary electrons should be less than unity. Stated in a different way, the electron velocity should be so low that the electrons will build up a negative charge on the mosaic. The electron velocity which will give this result depends somewhat upon the character of the mosaic and especially upon the nature of the light-sensitive material.
  • Fig. 2 in which parts similar to those in Fig. 1 are indicated by the same reference numerals, there is illustrated a circuit which causes the mosaic to be sprayed by electrons only during the return period of ascanning line.
  • control electrode 43 is connected through a portion of a potentiometer 49 and through a biasing battery 5
  • the potentiometer 49 is connected across the secondary Winding of a transformer 53, the primary Winding of the transformer having one end connected to ground and the other end connected through a coupling condenser 55 to one terminal of a horizontal deflecting coil 2
  • the voltage impulses which are applied through a coupling condenser 51 to the horizontal deflecting coils 2
  • applies a negative voltage to the control grid 43 of sufficient value to I1 uniblock the ow of electrons from the auxiliary cathode 4
  • Fig. 4 in which the curve 59 represents the synchronizing voltage impulses which are applied through the coupling condenser 51 to the deilecting coils 2l and to the transformer 53, and in which the curve 6I represents the resulting saw-tooth Wave of current which flows through the defiecting coils.
  • is such that the return of the electron beam at the end of a scanning line occurs while a voltage impulse 59 is being impressed upon the deflecting coils and the control grid 43. At the end of this return period, the electron beam is again deiiected to scan one line of the picture and during this period no electrons from the auxiliary cathode 4
  • the method of operating a cathode ray tube of the highly evacuated type having a mosaic of light sensitive elements so positioned that it may be scanned on the front side by an electron beam and also so positioned that an image of the picture to be transmitted may be formed on said front side, which method comprises producing a beam of high velocity electrons and scanning said mosaic iwith said beam whereby said mosaic is brought to an equilibrium potential due to the emission of secondary electrons, and spraying said light sensitive elements with electrons having a low velocity as compared with the velocity of the electrons in said beam, said low velocity being of such magnitudethat the ratio of secondary electrons to primary electrons is less than unity.

Landscapes

  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
US727228A 1934-05-24 1934-05-24 Television apparatus Expired - Lifetime US2147760A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US727228A US2147760A (en) 1934-05-24 1934-05-24 Television apparatus
FR790257D FR790257A (fr) 1934-05-24 1935-05-20 Appareil de télévision
NL73637A NL44769C (fr) 1934-05-24 1935-05-21
DE1935R0093420 DE699657C (de) 1934-05-24 1935-05-24 Fernsehsenderoehre
GB15170/35A GB434942A (en) 1934-05-24 1935-05-24 Improvements in or relating to cathode ray tubes and television and like transmitters incorporating the same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US727228A US2147760A (en) 1934-05-24 1934-05-24 Television apparatus

Publications (1)

Publication Number Publication Date
US2147760A true US2147760A (en) 1939-02-21

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
US727228A Expired - Lifetime US2147760A (en) 1934-05-24 1934-05-24 Television apparatus

Country Status (5)

Country Link
US (1) US2147760A (fr)
DE (1) DE699657C (fr)
FR (1) FR790257A (fr)
GB (1) GB434942A (fr)
NL (1) NL44769C (fr)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2454652A (en) * 1943-06-26 1948-11-23 Rca Corp Cathode-ray storage tube
US2464420A (en) * 1943-12-31 1949-03-15 Rca Corp Storage type cathode-ray tube
US2481458A (en) * 1943-10-12 1949-09-06 Bell Telephone Labor Inc Cathode-ray device
US2558120A (en) * 1950-01-17 1951-06-26 Jose W Acosta Push-pull electron tube for instruments or television
US2617963A (en) * 1949-05-26 1952-11-11 Int Standard Electric Corp Storage tube system
US2618762A (en) * 1945-04-12 1952-11-18 Rca Corp Target and circuit for storage tubes
US2651674A (en) * 1949-02-18 1953-09-08 Cathodeon Ltd Television transmission from intermittent film by means of pulsed pickup tube
US2735935A (en) * 1956-02-21 Image-translating device
US2813998A (en) * 1947-08-15 1957-11-19 Andrew V Haeff Method of storing, maintaining, and reproducing electrical signals, and means therefor
US2850565A (en) * 1952-01-24 1958-09-02 Farnsworth Res Corp Television camera tube arrangement with fading control utilizing an additional camera tube
US2983824A (en) * 1955-05-06 1961-05-09 Ibm Electro-optical point shutter
US2989658A (en) * 1958-08-22 1961-06-20 Fairchild Camera Instr Co Pickup tube

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE754133C (de) * 1935-08-14 1958-04-24 Fernseh Gmbh Mosaikelektrode fuer speichernde Bildzerlegerroehren
DE916175C (de) * 1950-10-28 1954-08-05 Cfcmug Bildzerlegerroehre

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2735935A (en) * 1956-02-21 Image-translating device
US2454652A (en) * 1943-06-26 1948-11-23 Rca Corp Cathode-ray storage tube
US2481458A (en) * 1943-10-12 1949-09-06 Bell Telephone Labor Inc Cathode-ray device
US2464420A (en) * 1943-12-31 1949-03-15 Rca Corp Storage type cathode-ray tube
US2618762A (en) * 1945-04-12 1952-11-18 Rca Corp Target and circuit for storage tubes
US2813998A (en) * 1947-08-15 1957-11-19 Andrew V Haeff Method of storing, maintaining, and reproducing electrical signals, and means therefor
US2651674A (en) * 1949-02-18 1953-09-08 Cathodeon Ltd Television transmission from intermittent film by means of pulsed pickup tube
US2617963A (en) * 1949-05-26 1952-11-11 Int Standard Electric Corp Storage tube system
US2558120A (en) * 1950-01-17 1951-06-26 Jose W Acosta Push-pull electron tube for instruments or television
US2850565A (en) * 1952-01-24 1958-09-02 Farnsworth Res Corp Television camera tube arrangement with fading control utilizing an additional camera tube
US2983824A (en) * 1955-05-06 1961-05-09 Ibm Electro-optical point shutter
US2989658A (en) * 1958-08-22 1961-06-20 Fairchild Camera Instr Co Pickup tube

Also Published As

Publication number Publication date
FR790257A (fr) 1935-11-16
NL44769C (fr) 1939-01-16
DE699657C (de) 1940-12-04
GB434942A (en) 1935-09-11

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