US2325676A - Cathode ray tube device - Google Patents

Cathode ray tube device Download PDF

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Publication number
US2325676A
US2325676A US429226A US42922642A US2325676A US 2325676 A US2325676 A US 2325676A US 429226 A US429226 A US 429226A US 42922642 A US42922642 A US 42922642A US 2325676 A US2325676 A US 2325676A
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US
United States
Prior art keywords
mosaic
tube
electrode
screen
target
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
US429226A
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English (en)
Inventor
Hepp Gerard
Mark Jan Van Der
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Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Application granted granted Critical
Publication of US2325676A publication Critical patent/US2325676A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/20—Measuring earth resistance; Measuring contact resistance, e.g. of earth connections, e.g. plates
    • G01R27/205—Measuring contact resistance of connections, e.g. of earth connections
    • 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
    • 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
    • H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
    • H01J29/36—Photoelectric screens; Charge-storage screens
    • H01J29/39—Charge-storage screens
    • H01J29/43—Charge-storage screens using photo-emissive mosaic, e.g. for orthicon, for 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
    • H01J29/86—Vessels; Containers; Vacuum locks
    • H01J29/88—Vessels; Containers; Vacuum locks provided with coatings on the walls thereof; Selection of materials for the coatings
    • 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

Definitions

  • the tube is a so-called iconoscope, in other words, if it contains a light sensitive mosaic which is scanned Aby the cathode ray, the pictures obtained with the aid of this tube always exhibit more or less troublesome patches of light.
  • the present invention includes also the iconoscope provided with such a screen.
  • the iconoscope shown is of the known type and is constituted by a bulb i containing the mosaic screen 2 to be scanned, which bulb passes with a conical part 3 into a cylindrical tube d containing a cathode 5, a control electrode 6 and an optical system 1, 8, 9. Further, the tube d is surrounded by coils I and la serving for electromagnetic deection of the cathode ray. The interior of the tube wall at the point of the coils Il),A and II is covered with a metal coating l2 which extends up to and including the conical part 3. This coating is indicated by shading.
  • the various supply wires are led into the tube by means'of a bush i3 which is fitted for this purpose with a certain number of contacts I4.
  • the filament of the cathode 5 is supplied by a transformer I5" Whose secondary winding is connected through a movable contact I6 to a point of a potentiometer I1.
  • This potentiometer is supplied with high voltage by a source of direct current which is not represented.
  • the so-called first anode 9 is directly connected to the earthed positive end of the said potentiometer. Hitherto it has been usual to connect also the coating directly to this end.
  • a condenser I8 is interposed in this connecting line so that, as previously, rapid potential variations of this coating are prevented, it is true, but the vaverage potential is no longer fixed. This is now going to be determined by the space charges inside the bulb, such as is the case with the glass inner wall of this bulb.
  • the coating I2 thus blocked can no longer carry off secondary electrons originating from the screen 2 so that all of them have to return either to the front or to the back of that screen. This would mean that the current in the leading-out wire of the screen 2 is at any time equal to the full intensity of the current of the ray. Consequently, if the ray is periodically suppressed, for example at the end of the lines of scanning, very strong voltage impulses will impinge through an output impedancer 20 the amplier (not shown) following after the tube,
  • the mosaic screen 2 is surrounded on all sides, except that on which is provided the light sensitive mosaic, by an auxiliary screen 2l which is insulated from the main screen 2 and i"s connected to earth through a leading-out wire 22 of its own.
  • the secondary electrons originating from the space in front of the main screen 2 and which would otherwise be carried off via the side and back walls of this screen are now collected by the auxiliary screen 2l.
  • the double function previously performed by the electrode I2 is thus divided over this coating and the auxiliary screen 2l.
  • a tube thus comprising an auxiliary screen is also advantageous in use when the coating I2 is directly connected to earth.
  • part of the current of the ray will tend to impinge at last on the back of the screen 2, resulting in the above mentioned drawback.
  • reduces this part of the current of the ray to a minimum.
  • Apparatus for television transmission comprising an evacuated envelope, electron gun means within said envelope to develop an electron beam, a target electrode positioned and ,adapted to develop secondary electrons when scanned by said beam, an electrode exposed to ⁇ said target between said target and said electron gun electrically disconnected over a direct current conducting path with other structure within and without said envelope, and means enclosing the surface of said target electrode not directly exg posed to said beam to collect secondary elctrons liberated by said target and prevent such collection by the said surface of said target.
  • Apparatus for television transmission comprising a tube having an electron gun to develop an electron beam, a photosensitive target adapted to be scanned and secondary electron emissive when scanned by said beam, a signal electrode coextensive and in capacitive relation with said target, an electrode between said gun and said target with no direct ⁇ electrical connection with said mosaic, said gun and said signal electrode, and a shield surrounding said signal electrode to collect secondary electrons and prevent collection of secondary electrons by said signal electrode.
  • Television transmitting apparatus comprising a tube having a secondary electron emissive photosensitive mosaic adapted to have developed thereon electrostatic charges representative of an optical image, a signal plate capacitively coupled to said mosaic, means to scan said mosaic with a beam of high velocity electrons to develop picture signals and inherently develop secondary electrons over the surface of said mosaic,
  • Television transmitting apparatus comprising a tube enclosing an electron gun to develop an electron beam, a mosaic target having one side exposed to and adapted to be scanned by said beam, a signal plate on the opposite side of said mosaic, an electrode surrounding a portion of the path of said beam between said gun and said mosaic, and an electrically conductive shield surrounding said mosaic and enclosing said signal plate, means to connect said signal plate through a load impedance to a point of positive potential and means to connect said electrode through a non-conductive capacitive path to said point of positive potential.
  • Television transmitting apparatus comprising a tube having an electron source, an anode to develop an electron beam, a mosaic target facing and exposed to said source to be scanned by said beam, a capacitive signal plate adjacent the opposite side of said mosaic from that facing said sour-ce, a shield electrode enclosing i said signal plate and having a border portion extending in the direction of said source beyond the mosaic surface facing said source, and an electrode surrounding a portion of the beam path between said source and said mosaic target, a potential source" connected between said electron source and said signal plate to maintain said l signal plate positive with respect to said source

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
  • Tires In General (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
US429226A 1939-09-22 1942-02-02 Cathode ray tube device Expired - Lifetime US2325676A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL95328A NL64723C (en(2012)) 1939-09-22 1939-09-22

Publications (1)

Publication Number Publication Date
US2325676A true US2325676A (en) 1943-08-03

Family

ID=19787957

Family Applications (1)

Application Number Title Priority Date Filing Date
US429226A Expired - Lifetime US2325676A (en) 1939-09-22 1942-02-02 Cathode ray tube device

Country Status (6)

Country Link
US (1) US2325676A (en(2012))
BE (1) BE440865A (en(2012))
DE (1) DE1080594B (en(2012))
FR (1) FR872140A (en(2012))
GB (2) GB551014A (en(2012))
NL (1) NL64723C (en(2012))

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2645740A (en) * 1948-06-22 1953-07-14 Emi Ltd Circuit arrangement embodying electron discharge devices employing target electrodes

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2645740A (en) * 1948-06-22 1953-07-14 Emi Ltd Circuit arrangement embodying electron discharge devices employing target electrodes

Also Published As

Publication number Publication date
FR872140A (fr) 1942-06-01
GB551014A (en) 1943-02-04
BE440865A (en(2012)) 1941-04-30
NL64723C (en(2012)) 1949-11-15
GB606489A (en) 1948-08-13
DE1080594B (de) 1960-04-28

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