US3497747A - High capacitance target structure for camera pick-up tube having dielectric sheet on metal mesh - Google Patents

High capacitance target structure for camera pick-up tube having dielectric sheet on metal mesh Download PDF

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Publication number
US3497747A
US3497747A US659776A US3497747DA US3497747A US 3497747 A US3497747 A US 3497747A US 659776 A US659776 A US 659776A US 3497747D A US3497747D A US 3497747DA US 3497747 A US3497747 A US 3497747A
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US
United States
Prior art keywords
sheet
mesh
dielectric
target
tube
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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
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US659776A
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English (en)
Inventor
Bernard C Einstein
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.)
TDK Micronas GmbH
ITT Inc
Original Assignee
Deutsche ITT Industries GmbH
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Assigned to ITT CORPORATION reassignment ITT CORPORATION CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: INTERNATIONAL TELEPHONE AND TELEGRAPH CORPORATION
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H01J29/41—Charge-storage screens using secondary emission, e.g. for supericonoscope
    • H01J29/413—Charge-storage screens using secondary emission, e.g. for supericonoscope for writing and reading of charge pattern on opposite sides of the target, e.g. for superorthicon

Definitions

  • a target for a vidicon, or'thicon or other television camera-type tube having an evaporated layer of silicon monoxide or silicon dioxide on a nickel or other conductive screen wire or electroformed mesh.
  • the evaporated layer is thus perforate at the holes in the mesh.
  • a 1000 angstrom imperforate sheet of silicon monoxide or other dielectric is then fixed to the evaporated layer.
  • the use of the thin sheet thus provides a high sheet-to-mesh capacitance for high resolution and a large dynamic range.
  • the target is more rugged than is con ventional because a molecular bond between the mesh and sheet increases rigidity.
  • This invention relates to the storage tube art, and more particularly to a rugged storage tube target having exceptionally good resolution and a wide dynamic range.
  • a storage tube target including a metal mesh having a perforate, evaporated layer of a first dielectric sandwiched between the mesh and a thin imperforate sheet of a second dielectric.
  • the first dielectric is employed to provide a foundation bonded to the mesh to which a uniform bond may be made with the sheet.
  • the evaporated layer has holes therethrough in registration with those of the mesh, the sheet covers these holes.
  • the target of the invention it is possible to make the sheet as thin as 1000 or 650 angstroms.
  • the sheet-to-mesh capacitance is thus very large and the target has a large charging capacity which makes its dynamic range large. That is, the size of the gray or half-tone region of operation is increased.
  • the large charging capacity also makes it possible to use What is known as a proximity focus. That is, a photosensitive surface may be located very near the sheet with a very low or zero primary electron accelerating voltage. The target may thus be properly charged without any attendant arcing or ICC,
  • a molecular bond between the evaporated layer and the mesh and sheet makes the entire target have a high integrity. It is therefore not severely damaged when subjected to considerable vibration and shock.
  • FIG. 1 is a side elevational view of a television cameratype tube partly in section
  • FIG. 2 is a transverse sectional view greatly enlarged, of a storage target shown in FIG. 1.
  • a storage tube is indicated at 10 having a glass envelope 11.
  • a photosensitive coating 12 is provided on the end of envelope 11.
  • a storage target is indicated at 13, and a collector grid is indicated at 14.
  • tube 10 may be operated as a vidicon or as an image orthicon.
  • collector grid 14 may or may not be omitted, as desired.
  • Tube 10 has an electron gun 15 for producing a scanning beam of electrons 16.
  • Tube 10 may be entirely conventional except for the construction and location of target 13.
  • Target 13 may be located sufficiently close to coating 12 so that a small or zero accelerating voltage may be applied between coating 12 and target 13. In other Words, a proximity focus may be employed. This is true because the charging capacity of target 13 is high. The manner in which such a high charging capacity is created is by the use of a very thin insulating sheet 17 shown in FIG. 2.
  • Target 13 may include a metal mesh 18 made of a woven screen of circular wires 19. Alternatively, mesh 18 may be an electroformed mesh having meshes of a square cross section.
  • mesh 18 is supported in a conventional clamp ring. It is stretched taut in the ring. A layer of silicon monoxide 20 is then evaporated on one side of mesh 18'by use of any conventional evap oration process. In lieu of silicon monoxide silicon dioxide may be employed, if desired.
  • the thickness of the dielectric at 20 is not critical but is preferably at least one micron and not greater than 50 microns. Mesh-to-sheet capacitance decreases with increased dielectric thickness. Structural strength and dielectric resistance to arcing and the like decrease with decreased dielectric thickness.
  • Sheet 17 is fixed to the dielectric at 20.
  • the dielectric at 20 may be bonded to mesh 18.
  • Sheet 17 may then be bonded to dielectric 20.
  • dielectric 20 may have a molecular bond with both.
  • sheet 17 may be additionally clamped to dielectric 20 by conventional clamp rings welded together as indicated at 21 and 22 in FIG. 2.
  • Mesh 18 and sheet 17 may be made from any one of several materials. Sheet 17 may also be fixed to dielectric 20 by any conventional method.
  • mesh 18 may be made of nickel, copper, silver or gold, or any alloy thereof.
  • Sheet 17 may be made of silicon monoxide, silicon dioxide, aluminum oxide, potassium chloride, sodium bromide, or magnesium oxide.
  • Mesh 18 should be as fine as possible. It preferably has at least 500 and preferably 1000 or 2000 or more lines per inch. However, the mesh becomes structurally weaker if it is finer than 2000 lines per inch.
  • Sheet 17 preferably has a thickness of about 1000 angstroms. However, this thickness is not critical. For example, an electroformed sheet of A1 of a thickness of 650 angstroms may be employed.
  • the aluminum oxide sheet may be electroformed in the conventional way. In general, the aluminum oxide sheet will be supported on the surface of quantity of water. Mesh 18 will be supported below the waters surface in a pan with dielectric 20 on the upper side of the mesh. The water is drained out and the sheet 17 is then lowered onto dielectric 20 in a manner similar to that used in the prior art in preparing phosphor screens.
  • a drop of lacquer consisting essentially of any conventional nitrocellulose in a solvent is placed on top of the surface of a quantity of water having an upper surface dimension of 12 in. by 18 in.
  • the film sets to a fairly hard state almost immediately.
  • the water is then drained to allow the film'to deposit on dielectric 20 as before.
  • Silicon monoxide may then be evaporated on to the lacquer film by a conventional process.
  • the target is then baked until the lacquer is evaporated. This will produce sheet 17 of silicon monoxide having a molecular bond to dielectric 20, which also may be made of silicon monoxide,
  • the mesh may have interstices of an area equal to one-half or considerably more than one-half of the area of the mesh.
  • electron beam 16 is directed toward target 13 on the side thereof on which mesh 18 is bare.
  • Primary electrons from coating 12 are directed against the surface of sheet 17 opposite the surface thereof which lies in contact With dielectric 20.
  • target 13 with a dielectric sheet 17 of an extremely small thickness,
  • the capacitance between the surface of sheet 17 which is charged by the primary electrons and mesh 18 is therefore very large. This permits the use of said proximity focus and a low zero primary accelerating voltage. This, in turn, prevents arcing and electric field distortion in the target 13 for a highly reliable resolution.
  • the high capacitance also increases the dynamic range of the target 13.
  • a clamping device can also act as an additional or independent brace.
  • a storage tube target comprising: a conductive wire mesh; a first dielectric evaporated on one side of said mesh having holes therethrough in registration with the holes in said mesh; and an imperforate sheet of a second dielectric bonded to said first dielectric in a position covering said registering holes.
  • said first dielectric is a perforate evaporated layer of silicon monoxide having a maximum thickness of at least one and not more than fifty microns, said layer being bonded to both said mesh and said sheet.
  • said first dielectric is a layer of silicon dioxide havng a maximum thickness of at least one and not more than fifty microns

Landscapes

  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
  • Electrodes For Cathode-Ray Tubes (AREA)
US659776A 1967-08-10 1967-08-10 High capacitance target structure for camera pick-up tube having dielectric sheet on metal mesh Expired - Lifetime US3497747A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US65977667A 1967-08-10 1967-08-10

Publications (1)

Publication Number Publication Date
US3497747A true US3497747A (en) 1970-02-24

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US659776A Expired - Lifetime US3497747A (en) 1967-08-10 1967-08-10 High capacitance target structure for camera pick-up tube having dielectric sheet on metal mesh

Country Status (7)

Country Link
US (1) US3497747A (enrdf_load_stackoverflow)
BE (1) BE719247A (enrdf_load_stackoverflow)
CH (1) CH483720A (enrdf_load_stackoverflow)
DE (1) DE1764802A1 (enrdf_load_stackoverflow)
FR (1) FR1576868A (enrdf_load_stackoverflow)
GB (1) GB1228180A (enrdf_load_stackoverflow)
NL (1) NL6811255A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3564321A (en) * 1969-05-01 1971-02-16 Gen Electric Mesh-reinforced secondary electron conduction target for camera tubes
DE2119010A1 (de) * 1970-05-01 1971-11-18 Hughes Aircraft Co Speicherelektrode für Speicherröhren zur Rasterumwandlung
US3755865A (en) * 1969-05-01 1973-09-04 Gen Electric Novel mesh-reinforced sec target for camera tubes
DE2327253A1 (de) * 1973-05-29 1975-01-02 Litton Industries Inc Lichtverstaerker
US3960562A (en) * 1973-04-30 1976-06-01 Raytheon Company Thin film dielectric storage target and method for making same

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2237681A (en) * 1937-12-03 1941-04-08 Emi Ltd Television transmitting tube
US2579772A (en) * 1949-10-17 1951-12-25 Remington Rand Inc Method of making an image storage screen
US2713648A (en) * 1953-03-06 1955-07-19 Raytheon Mfg Co Image storage devices
US2922906A (en) * 1956-12-26 1960-01-26 Gen Electric Target electrode assembly
US3179834A (en) * 1960-10-27 1965-04-20 Rca Corp Pickup tube target structure and method of manufacturing the same
US3408531A (en) * 1966-06-10 1968-10-29 Westinghouse Electric Corp Storage system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2237681A (en) * 1937-12-03 1941-04-08 Emi Ltd Television transmitting tube
US2579772A (en) * 1949-10-17 1951-12-25 Remington Rand Inc Method of making an image storage screen
US2713648A (en) * 1953-03-06 1955-07-19 Raytheon Mfg Co Image storage devices
US2922906A (en) * 1956-12-26 1960-01-26 Gen Electric Target electrode assembly
US3179834A (en) * 1960-10-27 1965-04-20 Rca Corp Pickup tube target structure and method of manufacturing the same
US3408531A (en) * 1966-06-10 1968-10-29 Westinghouse Electric Corp Storage system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3564321A (en) * 1969-05-01 1971-02-16 Gen Electric Mesh-reinforced secondary electron conduction target for camera tubes
US3755865A (en) * 1969-05-01 1973-09-04 Gen Electric Novel mesh-reinforced sec target for camera tubes
DE2119010A1 (de) * 1970-05-01 1971-11-18 Hughes Aircraft Co Speicherelektrode für Speicherröhren zur Rasterumwandlung
US3960562A (en) * 1973-04-30 1976-06-01 Raytheon Company Thin film dielectric storage target and method for making same
DE2327253A1 (de) * 1973-05-29 1975-01-02 Litton Industries Inc Lichtverstaerker

Also Published As

Publication number Publication date
GB1228180A (enrdf_load_stackoverflow) 1971-04-15
BE719247A (enrdf_load_stackoverflow) 1969-02-10
CH483720A (de) 1969-12-31
DE1764802A1 (de) 1971-11-04
FR1576868A (enrdf_load_stackoverflow) 1969-08-01
NL6811255A (enrdf_load_stackoverflow) 1969-02-12

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Owner name: ITT CORPORATION

Free format text: CHANGE OF NAME;ASSIGNOR:INTERNATIONAL TELEPHONE AND TELEGRAPH CORPORATION;REEL/FRAME:004389/0606

Effective date: 19831122