US2156391A - Television transmitting tube - Google Patents

Television transmitting tube Download PDF

Info

Publication number
US2156391A
US2156391A US118482A US11848236A US2156391A US 2156391 A US2156391 A US 2156391A US 118482 A US118482 A US 118482A US 11848236 A US11848236 A US 11848236A US 2156391 A US2156391 A US 2156391A
Authority
US
United States
Prior art keywords
coating
electrode
light
image
mosaic
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
US118482A
Other languages
English (en)
Inventor
Hickok Willard
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 US118482A priority Critical patent/US2156391A/en
Priority to GB32403/37A priority patent/GB491413A/en
Priority to FR830476D priority patent/FR830476A/fr
Priority to DE1937R0101126 priority patent/DE692033C/de
Application granted granted Critical
Publication of US2156391A publication Critical patent/US2156391A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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

Definitions

  • My invention relates to improvements to cathode ray television transmitting tubes, and particularly to an improved photosensitive electrode structure for use in such tubes.
  • cathode ray transmitter In the usual form of cathode ray transmitter the image of an object to be transmitted is focused on the front surface of a target or mosaic electrode consisting in general of a thin transparent insulating sheet, such as mica, with a great number of discrete photoelectrically sensitive elements on the front and a signal electrode comprising a metallic coating on the opposite surface, the front or illuminated surface being scanned by a cathode ray beam to generate picture signals which are collected from the metallic coating.
  • These picture signals which are electrical impulses representative of the light values of elemental areas of the image, may be amplified and applied to a cathode ray type of receiving tube to produce a visible reproduction of the image.
  • I provide the target or mosaic electrode with a black non-refleeting and preferably electrically conducting surface on the side of the photo-electrically sensitive electrode opposite that side on which the optical image of an object is focused.
  • Figure 1 is a diagrammatic view illustrating one form of my television device
  • Figure 2 is a diagrammatic view partially in section showing" in enlarged detail a portion of the electrode structure shown in Figure 1;
  • Figure 3 is a similar View of one modification of the electrode structure shown in Figure 2.
  • the tube comprises a highly evacuated glass envelope or bulb l with a tubular arm or neck section enclosing a conventional type electron gun and a spherical section enclosing a flat target or mosaic electrode 2 so positioned that its front surface may be scanned by a beam of electrons from the electron gun and also may have projected upon it the optical image to be transmitted. Since the image is produced from an object situated outside the tube, that portion of the spherical section opposite-the electrode 2 is made optically uniform so that the image to be transmitted may be projected upon the electrode with a minimum of distortion by the lens 4.
  • the electron gunv assembly is of the conventional type, and comprises a cathode 5 from which an electron stream may be drawn, a control electrode 6 connected to the usual biasing battery, and a first anode l maintained positive with respect to the cathode 5.
  • the electron stream leaving the first anode is accelerated and concentrated into an electron scanning beam focused on the front surface of the target 2 by a second anode 8, which is preferably a conductive coating on the surface of the envelope I near the neck of the bulb but removed from that portion through which is projected the optical image to be transmitted.
  • the first anode l and the second anode 8 are maintained at the desired positiv-epotentials with respect to the cathode 5 by a battery 9.
  • deflection means such as deflection coils I 0 and l I may be used to sweep the beam in a horizontal and vertical plane, respectively, to scan the mosaic electrode. It is obvious that conventional electrostatic deflection plates may be substituted for the deflection coils if desired.
  • the photosensitive mosaic surface which is scanned by the electron beam and on which the image to be transmitted is focused is, as best shown in Figure 2,. formed on one side of a thin transparent sheet of insulation, such as mica, which has been found to be very satisfactory for the purpose.
  • a black non-reflective coating preferably of graphite, or other material which will produce a black non-reflective surface and has satisfactory electrical conductivity.
  • Such non-reflecting material is in inductive relationship with the mosaic surface and serves as an electrode for collecting the picture signals.
  • the mosaic electrode 2 Iselect a sheet of mica l2 of the desired area having a uniform thickness of approximately two thousandths of an inch and as a first step coat one side of the sheet with finely divided silver oxide which is reduced to provide a surface of individually separated silver globules i3, which are subsequently oxidized and sensitized with caesium during the evacuation process.
  • Such an electrode structure is disclosed by Essig in his U. S. Patent 2,065,570, Serial No. 594,779, issued December 29, 1936, and assigned to Radio Corporation of America.
  • the next step in preparing the electrode is to deposit on the opposite side of the sheet of mica a uniform coating of graphite or other black non-reflecting electrically conducting material M, which may conveniently be done by spraying with the desired material.
  • a 50% aqueous solution of substantially colloidal graphite such as the material commercially referred to as Aquadag, is very suitable for the purpose.
  • the thin mica sheet I2 which carries the individual silver globules on one side and the black coating on the opposite side, and which is inherently weak because of its thinness, I prefer to use a relatively thick backing sheet [5, also preferably of mica and of the same size as the sheet 12.
  • a relatively thick backing sheet [5, also preferably of mica and of the same size as the sheet 12.
  • On the side of the backing sheet facing the black coating I4 I provide a conductive coating It, preferably of metal such as platinum, in good electrical contact with the black coating I4 to assure minimum resistance between various points on the coating M and the external circuit which is connected through the lead I! to a frame or clip member l8 which grips the edges of the two micas and which is in electrical contact with the coating I6.
  • the mosaic supporting mica l5 also serves as a cover or mask for the electrically conducting non-reflecting material on the mica l2 which if grahphite or carbon has the property of absorbing the caesium with which the silver globules are sensitized. It may, however, be advantageous to provide means whereby excess caesium may be absorbed and to this end I provide openings E9 in the member l5 thereby exposing a portion of the coating I4 to the atmosphere of the tube.
  • FIG. 3 shows a modification wherein the black non-reflecting coating 20 is of such material and in this modification, I prefer to deposit directly on the non-reflective coating a layer or film of metal or other electrically conducting material 2
  • Adequate mechanical support for the mosaic electrode may likewise be given by the mica sheet 15 which may be coated with an electrical conductor I6 whereby electrical contact may be accomplished as in the foregoing example.
  • the frame or clip member 18 in contact with the conductive coating or signal electrode I4 is connected through the impedance 22 to ground and the second anode 8, and in operation the current flow in this circuit produces a voltage drop across the impedance 22 which may be impressed on the input of a translating device 23, further amplified, and applied to a transmitting network in a manner well known to the art.
  • Transparent or translucent insulators having continuous films of light sensitive materials have been used in place of the Inosaiclike structure and my invention is likewise applicable to these modifications wherein the films are semi-transparent or translucent to such a degree that light may be reflected by any other than a black non-reflective coating on the opposite side of the insulator.
  • a cathode ray television transmitting tube comprising an envelope having a light transmitting vitreous portion which is inherently light reflecting on the surface facing the interior of the envelope for the transmission of an optical image, an electrode assembly including a translucent base exposed to said portion, a light sensitive material on the side of said base facing said vitreous portion, and a black coating substantially non-reflective to light on the opposite side of said base.
  • a cathode ray television transmitting tube comprising an envelope having a light transmitting vitreous portion which is inherently light reflecting on the surface facing the interior of the envelope for the transmission of an optical image, an electrode assembly including a translucent base exposed to said portion, a light sensitive material on the side of said base facing said vitreous portion, a coating substantially non-reflective to light on the opposite side of said base, and an electrically conductive coating in contact with said non-reflective coating.
  • a cathode ray television transmitting tube comprising an envelope having a light transmitting glass window for the transmission of an optical image, an electrode assembly including a translucent base exposed to said window, a light sensitive material on the side of said base facing said window, a coating of carbon on the opposite side of said base, and a cover over said coating having means for exposing a portion of said coating to the interior of said envelope.
  • a photosensitive electrode structure which comprises a translucent base, a translucent photosensitive mosaic on one side of said base and a black light absorbing and non-reflecting coating on the opposite side of said base.
  • a photosensitive electrode structure which comprises a translucent sheet of mica, a plurality of isolated photosensitive particles formed on one side of said translucent sheet of mica and a black substantially non-reflective coating of carbon on the opposite side of said base.

Landscapes

  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
US118482A 1936-12-31 1936-12-31 Television transmitting tube Expired - Lifetime US2156391A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US118482A US2156391A (en) 1936-12-31 1936-12-31 Television transmitting tube
GB32403/37A GB491413A (en) 1936-12-31 1937-11-24 Improvements in or relating to cathode ray television transmitter tubes
FR830476D FR830476A (fr) 1936-12-31 1937-12-07 Tube transmetteur de télévision
DE1937R0101126 DE692033C (de) 1936-12-31 1937-12-24 Einseitiger Mosaikschirm fuer Kathodenstrahlsenderoehren

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US118482A US2156391A (en) 1936-12-31 1936-12-31 Television transmitting tube

Publications (1)

Publication Number Publication Date
US2156391A true US2156391A (en) 1939-05-02

Family

ID=22378875

Family Applications (1)

Application Number Title Priority Date Filing Date
US118482A Expired - Lifetime US2156391A (en) 1936-12-31 1936-12-31 Television transmitting tube

Country Status (4)

Country Link
US (1) US2156391A (fr)
DE (1) DE692033C (fr)
FR (1) FR830476A (fr)
GB (1) GB491413A (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE743019C (de) * 1939-04-03 1943-12-16 Philips Patentverwaltung Einseitiger photoelektrischer Mosaikschirm fuer speichernde Bildsenderoehren

Also Published As

Publication number Publication date
GB491413A (en) 1938-09-01
FR830476A (fr) 1938-08-01
DE692033C (de) 1940-06-11

Similar Documents

Publication Publication Date Title
US2654853A (en) Photoelectric apparatus
US2177736A (en) Television transmitting apparatus
US2169840A (en) Cathode-ray signal-generating tube
US2622219A (en) Television image tube
US2403239A (en) Target electrode for electron discharge tubes
US2240186A (en) Electron discharge device
US2151785A (en) Electron discharge device
US2195489A (en) Television transmitting tube
US2744837A (en) Photo-conductive targets for cathode ray devices
US2100259A (en) Television
McGee et al. EMI cathode-ray television transmission tubes
US2189985A (en) Electrode structure
US2250283A (en) Electron discharge device
US2175691A (en) Photovoltaic target
US2156391A (en) Television transmitting tube
GB462550A (en) Improvements in or relating to television transmission systems comprising cathode ray tubes
US2156392A (en) Television transmitting apparatus
US3026437A (en) Electron discharge device
US3437860A (en) Image orthicon glass target with aluminum-tantalum oxide coating
US2175692A (en) Television transmitting tube
US2324505A (en) Television transmitting tube and electrode structure
US3189781A (en) Image tube utilizing transmissive dynode-type target
US2256461A (en) Electron image tube
US2244365A (en) Electron discharge device
US2178232A (en) Cathode ray tube