US2222940A - Mosaic electrode structure - Google Patents

Mosaic electrode structure Download PDF

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Publication number
US2222940A
US2222940A US208744A US20874438A US2222940A US 2222940 A US2222940 A US 2222940A US 208744 A US208744 A US 208744A US 20874438 A US20874438 A US 20874438A US 2222940 A US2222940 A US 2222940A
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US
United States
Prior art keywords
mosaic
silver
layer
plate
base
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Expired - Lifetime
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US208744A
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English (en)
Inventor
Freeman George Stanle Percival
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.)
EMI Ltd
Electrical and Musical Industries Ltd
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EMI Ltd
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Filing date
Publication date
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Publication of US2222940A publication Critical patent/US2222940A/en
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    • 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

  • This invention relates to mosaic electrode structures 'for use in cathode ray television and similar apparatus.
  • the invention is concerned with the kind of mosaic structure in which a 5 multiplicity of mutually insulated metallic elements are formed on the surface of an insulating carrier or base plate.
  • a cathoderay tube transmitting apparatus comprising a mosaic electrodestructure consisting of a multiplicity of mutually insulated photo-sensitive elements upon which an image of an object for transmission is projected the individual elements acquiring electrostatic charges according to the intensity of the incident light image and the elements are periodically restored toa datum value on being scanned by a cathode ray beam, or in some cases by a light beam, restoration of the elements to the datum potential generating in a conductive signal plate associated with the mosaic electrode picture signals suitable for transmission.
  • an electron image of an object for transmission is projected onto a mosaic structure, which in this case is not rendered photo-sensitive, the electron image releasing secondary electrons on impact with themosaic screen, the release of secondary-electrons causing the elements of the screen to acquire electrostatic chargeswhich-are periodically restored to-a datum value by scanning with a suitable scanning beam.
  • the process of making mosaic electrode structures as heretofore adopted has necessitated heat treatment of the silver-layer in order to cause aggregation into minute globules.
  • his the object of the present invention to provide an improved method of making mosaic electrode structures in which the necessity for heating the electrode for the production of the mosaic I formation is avoided.
  • a method of making a mosaic electrode structure in which a suitable metal is applied to an insulating base-plate or support in a sufiiciently thin layer that the particles of metal deposited on the .base-plateare adequately insulated from one another whilst a sufiicient number of particles is applied to the surface as eiiectively to constitute amosaic electrode without the necessity of heating the metalliclayerto cause aggregation into minute globules.
  • the metal employed for coating the base-plate which is preferably a sheet of mica, will in most cases .be silver since this metal is found to be particularly suitable for use in the invention and can bereadily oxidised when it is desired to prepare a photo-sensitive mosaic electrode since the silver-oxide has great affinity for the usual-photo-sensitive material employed, namely, caesium.
  • the television transmitting tube shown in the drawing “comprises an evacuated envelope l in which there is suspended in known manner a mica support or base-plate 2 having on one side a conductive signal'plate 3 and on'the other side a mosaic structure indicatedby the dotted line 4.
  • a cathode 6 associated with other electrodes in known manner'which serves to focus a beam of electrons emanating from the cathode 6 for the purpose of scanning the mosaic screen 4, the beam being deflected in known manner by. suitable coils or electrostatic deflection plates.
  • the'mosaic structure is rendered photo-sensitive and on projecting an optical image onto the mosaic structure througha "suitable optical systemindicated at 1, the elements of the mosaic structure emit photo-electrons causing theelements to become electrostatically charged and these charges are periodically restored to a datum potential by scanning with the electron beam,
  • a layer of silver is usually applied to the support 2 and the support is subsequently heated to cause the silver to assume aglobular formation, as stated above.
  • a sufliciently thin layer of a suitable metal, preferably silver is applied to the mica support 2, the thinness of the layer being such that the particles of the metal are adequately insulated from one another and are sufiicient in number so as to function effectively as a mosaic structure.
  • the support can be weighed before and after the evaporating process and the amount, by weight of silver, necessary for the layer, can be ascertained, and for the manufacture of subsequent electrodes one or more tungsten or other suitable filaments or coils may be plated with the required'weight of silver, the tungsten coils being then used for the manufacture of furtherelectrodes the silver depositedon the tungsten filaments or coils being evaporated onto the support transparent or otherwise by heating the filaments.
  • the critical thick ness of layer above mentioned, for silver,-occurs when the transparency of themetal-film to trans-. mitted light is approximately 70 80%, and hence, providing this critical value is not reached, mosaic electrodes can be constructed sufilcient for practical purposes Without the necessity of heat: ing the layer to cause aggregation, as has here- 'tofor'e been considered necessary.
  • the mosaic electrodes can be manufactured in situ within the evacuated envelope I.
  • the usual steps of oxidising the layer and admitting caesium to sensitise the screen may be adopted. If desired, after sensitising, 'an additional thin layer of silver may be deposited, as referred to in the specification of British Patent No. 480,946.
  • th invention is applied to the type of television transmitting tube in which an electron image is projected onto a mosaic structure, the step of sensitising the mosaic screen will of course .be omitted.
  • the degree of insulation necessary between the elements of the mosaic structure depends upon the conditions under, which the apparatus is operated.
  • the specific description for the production of a mosaic elec, trode in accordance with the invention has been given on the assumption that the structure will be applied to a television transmitting tube in which 25 picture frames per second are scanned.
  • the insulation between the elements is such that there is substantially no leakage of charge from one element to the other in a frame period, i. e., /2 of a second.
  • a method of fabricating a mosaic electrode structure having an insulating-base member and a signal plate on one side thereof which comprises the steps of ascertaining the light conductivity of the base, applying a suitable substantially non-photoelectric metal to the insulating base plate surface opposite the signalplate as a layer of non-contiguous particles of the metal, and continuing the application of the metal to the insulating base plate until the light conductivityof the base and layer of particles is reduced in the order of 20 to 30 percent of the original light conductivity of the base so that a mosaic surface of substantially non-contiguous and electrically isolated metal particles functioning as a multiplicity of condenser elements in cooperation with the signal plate.
  • a method of fabricating a mosaic electrode structure having an insulating base member anda signal plate on one side thereof which comprises the steps 'of determining the light conductivity of the base member, evaporating metallic, silver onto the insulating base-surface'opposite the signal plate as a layer of discrete non-contiguous particles of the evaporatedsilver, th'epaiticles being electrically insulated one from .the:
  • a method of fabricatinga mosaic electrode structure having a light conductive insulating base member which comprises the steps, of ascertaining the light transparency of the. base mem-: ber, applying a suitable substantially non-jphotoelectric metal to th surface of :the insulating percent of the original light transparency of the' base member, at which tim a suflicient number of metallic particles are applied to constitute effectively a mosaic electrode wherein the receptive particles thereof are substantially non-contiguous 5 and electrically isolated one from the other.

Landscapes

  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
US208744A 1937-05-28 1938-05-19 Mosaic electrode structure Expired - Lifetime US2222940A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB14800/37A GB498134A (en) 1937-05-28 1937-05-28 Improvements in or relating to mosaic electrode structures for use in cathode ray apparatus for television and similar purposes

Publications (1)

Publication Number Publication Date
US2222940A true US2222940A (en) 1940-11-26

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Family Applications (1)

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US208744A Expired - Lifetime US2222940A (en) 1937-05-28 1938-05-19 Mosaic electrode structure

Country Status (4)

Country Link
US (1) US2222940A (de)
DE (1) DE878221C (de)
FR (1) FR838520A (de)
GB (1) GB498134A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115376756A (zh) * 2022-07-29 2022-11-22 华南理工大学 一种基于熔化凝固法的稳定电控过冷相变镶嵌电极及其制备方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE743586C (de) * 1942-07-16 1943-12-29 Telefunken Gmbh Verfahren zur Herstellung eines Antimon-Mosaiks fuer speichernde Bildsenderoehren

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115376756A (zh) * 2022-07-29 2022-11-22 华南理工大学 一种基于熔化凝固法的稳定电控过冷相变镶嵌电极及其制备方法
CN115376756B (zh) * 2022-07-29 2023-06-20 华南理工大学 基于熔化凝固法的稳定电控过冷相变镶嵌电极的制备方法

Also Published As

Publication number Publication date
FR838520A (fr) 1939-03-08
GB498134A (en) 1938-12-28
DE878221C (de) 1953-06-01

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