US3885188A - Target assembly for storage tubes and a method of making the same - Google Patents

Target assembly for storage tubes and a method of making the same Download PDF

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Publication number
US3885188A
US3885188A US341898A US34189873A US3885188A US 3885188 A US3885188 A US 3885188A US 341898 A US341898 A US 341898A US 34189873 A US34189873 A US 34189873A US 3885188 A US3885188 A US 3885188A
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US
United States
Prior art keywords
target assembly
screen
target
organic compound
storage tubes
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
US341898A
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English (en)
Inventor
Yujiro Koike
Haruo Maeda
Tsutomu Nishino
Akimitu Aoyama
Yuji Mogi
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.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
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 Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Application granted granted Critical
Publication of US3885188A publication Critical patent/US3885188A/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
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/20—Manufacture of screens on or from which an image or pattern is formed, picked up, converted or stored; Applying coatings to the vessel
    • 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

Definitions

  • This invention relates generally to a target assembly for use with charge storage tubes, and in particular to a method of producing a target assembly having an organic compound film.
  • Storage of picture signals for a predetermined period of time will find many uses in future telecommunication applications including displaying of a still picture, such as documents, on a video telephone system, monitoring pictures being transmitted or received on a facsimile and displaying of picture signals interleaved with signals of the conventional broadcast television or CATV systems.
  • Storage tubes will meet these requirements and a number of types of storage tube are already known in the art.
  • One prior art storage tube is provided with a target assembly which comprises a photoconductive layer, or a photocathode as it is usually called in the art, placed on one side thereof facing the scene to be imaged and an insulating layer on the other for storing charges developed as a result ofa light incident upon the photocathode, the charged information being read out by impingement of an electron beam.
  • a target assembly which comprises a photoconductive layer, or a photocathode as it is usually called in the art, placed on one side thereof facing the scene to be imaged and an insulating layer on the other for storing charges developed as a result ofa light incident upon the photocathode, the charged information being read out by impingement of an electron beam.
  • Another prior art storage tube employs a writing gun instead of a photocathode for charging electrons on the target and a reading gun for discharging the electron charges.
  • Still another type uses a single electron gun to serve the dual purposes of writing and reading binary information.
  • a target assembly used for such applications is composed of a metal screen on which a layer of an inorganic compound such as calcium fluoride (CaF silicon dioxide (SiO or such a porous inorganic compound as potassium chloride (KCl) is deposited.
  • An inorganic compound such as calcium fluoride (CaF silicon dioxide (SiO or such a porous inorganic compound as potassium chloride (KCl) is deposited.
  • Another prior art target assembly comprises a silicon substrate and a layer of silicon dioxide deposited thereon in the form of a mesh or dots.
  • the important requirements for a charge storage target are uniformities of charge contrast, power of reso lution, image gradation and writing and reading speeds over the entire surface of the target. To meet these requirements it is necessary to ensure uniformities of secondary emission characteristics, film thickness of the insulator compound and electrical resistance and ca pacitance of the insulator compound.
  • Another object of the present invention is to provide a simplified method of producing at a low cost target assemblies having a uniform storage time from one sample to another.
  • Still another object of the invention is to provide an improved storage target assembly having a long lifetime.
  • FIG. 1 is an enlarged side view of a target assembly according to the present invention showing droplets of organic compound deposited on a metal screen;
  • FIG. 2 is an enlarged side view of the target assembly of FIG. 1 showing the organic compound spread out over the surface of the screen;
  • FIG. 3 is an enlarged side view of the target assembly of FIG. 2 in solid state after a firing process
  • FIG. 4 is an enlarged side view of a pair of the target assemblies of FIG. 3 connected in rear-to-rear relation with each other.
  • FIG. 1 A first embodiment of the present invention is shown in FIG. 1 and comprises a target assembly generally indicated at reference numeral 10.
  • the target assembly 10 comprises a meshed metal screen 11 formed. for example, of copper and having a thickness of about 3 mi crons.
  • droplets 12 of an organic compound such as polyimide enamel, known under Duponts Trade Name Polyimide Wire Enamel or polyamideimide enamel are deposited by means of spraying or painting or other known methods.
  • the screen 11 is then placed in a spinner (not shown) and rotated at high speed to cause the droplets 12 of the organic compound to drift sideways by centrifugal force and drift downwardly into the interstices 13 by gravita tional force.
  • the droplets are spread out over the entire surface of the screen as shown in FIG. 2. Under this condition surface irregularities possibly develop over the target surface.
  • the screen 11 is heated in air to a temperature in the range of about lOU to 200C and maintained there for about 3 hours. During the heating process, the solvent of the organic compound is evaporated causing a mechanical stress to develop within the compound. The stress acts in such a way as to eliminate the surface irregularities, thus providing an organic compound film 14 with a uniform thickness over the entire target surface.
  • FIG. 4 illustrates a second embodiment of the invention.
  • a target assembly 20 comprises a pair of targets 10 prepared by the method as previously described.
  • the targets 10 are connected in rear-to-rear relation to each other with the screen sides facing outside.
  • the tar get assembly 15 may be useful for two-gun storage tubes in which one side of the assembly 15 serves as a target for the writing gun and the other side as a target for the reading gun.
  • the charge storage time is determined by the resistance measured across the interstice 13.
  • the resistance is in turn determined by the size of the interstice and the thickness of the resultant organic compound film 14.
  • a 500- to l500-mesh screen and a film thickness of from about 1 micron to 20 microns result in a charge storate time in the range of 3 to minutes.
  • the metal screen 11 may be formed of any metal of the type which is stable in vacuum such as copper, aluminium and silver, or may be constructed on a glass screen of such material as to permit deposition of metal or conductive material thereon and to permit provision of an optically flat surface.
  • the screen 11 may be of a grid type comprising a plurality of parallel metal strips. If metal strips are used in the arrangement of the target assembly 15, targets are connected in such a way that the strips of one target side run normal to the direction of the strips of the other target.
  • a target assembly for use with charge storage tubes comprising a screen having interstices therein and a film of an organic compound of a resistivity of at least 10 ohm-cm deposited on said screen, wherein said organic compound is selected from the group consisting of polyimide and polyamideimide, and wherein said compound has a uniform thickness over the entire target surface, whereby said organic compound is capable of storing electrostatic charges for an extended period of time.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Electroluminescent Light Sources (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Physical Vapour Deposition (AREA)
US341898A 1972-03-17 1973-03-16 Target assembly for storage tubes and a method of making the same Expired - Lifetime US3885188A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP47027766A JPS4895769A (enrdf_load_stackoverflow) 1972-03-17 1972-03-17

Publications (1)

Publication Number Publication Date
US3885188A true US3885188A (en) 1975-05-20

Family

ID=12230103

Family Applications (1)

Application Number Title Priority Date Filing Date
US341898A Expired - Lifetime US3885188A (en) 1972-03-17 1973-03-16 Target assembly for storage tubes and a method of making the same

Country Status (5)

Country Link
US (1) US3885188A (enrdf_load_stackoverflow)
JP (1) JPS4895769A (enrdf_load_stackoverflow)
CA (1) CA952963A (enrdf_load_stackoverflow)
DE (1) DE2313197A1 (enrdf_load_stackoverflow)
FR (1) FR2176725B1 (enrdf_load_stackoverflow)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2538836A (en) * 1948-10-15 1951-01-23 Rca Corp Barrier grid storage tube
US3067486A (en) * 1957-06-20 1962-12-11 Itt Target electrode for barrier grid storage tube and method of making same
US3617791A (en) * 1968-03-14 1971-11-02 Siemens Ag Image intensifier including polyimide support

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2538836A (en) * 1948-10-15 1951-01-23 Rca Corp Barrier grid storage tube
US3067486A (en) * 1957-06-20 1962-12-11 Itt Target electrode for barrier grid storage tube and method of making same
US3617791A (en) * 1968-03-14 1971-11-02 Siemens Ag Image intensifier including polyimide support

Also Published As

Publication number Publication date
CA952963A (en) 1974-08-13
DE2313197A1 (de) 1973-10-04
FR2176725A1 (enrdf_load_stackoverflow) 1973-11-02
JPS4895769A (enrdf_load_stackoverflow) 1973-12-07
FR2176725B1 (enrdf_load_stackoverflow) 1976-04-30

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