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US3320465A - Mesh with raster-size aperture for dampening vibrations of camera tube mesh - Google Patents

Mesh with raster-size aperture for dampening vibrations of camera tube mesh Download PDF

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Publication number
US3320465A
US3320465A US396196A US39619664A US3320465A US 3320465 A US3320465 A US 3320465A US 396196 A US396196 A US 396196A US 39619664 A US39619664 A US 39619664A US 3320465 A US3320465 A US 3320465A
Authority
US
United States
Prior art keywords
mesh
tube
meshes
aperture
raster
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
US396196A
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English (en)
Inventor
Ruggles Percy Charles
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.)
Teledyne UK Ltd
Original Assignee
English Electric Valve 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 English Electric Valve Co Ltd filed Critical English Electric Valve Co Ltd
Application granted granted Critical
Publication of US3320465A publication Critical patent/US3320465A/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
    • 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
    • H01J29/08—Electrodes intimately associated with a screen on or from which an image or pattern is formed, picked-up, converted or stored, e.g. backing-plates for storage tubes or collecting secondary electrons

Definitions

  • a serious defect which has long been experienced in Vidicons, image orthicons and other camera tubes is that known as microphony of the mesh which, in such tubes, is near the scanned targe of the tube.
  • the scanned target is, of course a layer of photo-conductive material and the mesh-the so-called field meshis a short distance (usually about 2 mm.) on the electron gun side of the target.
  • the scanned target is a secondary electron emitting layer and the mesh is very closely adjacent thereto on the side thereof remote from the electron gun.
  • the present invention seeks substantially to reduce or eliminate mesh microphony in a camera tube in a simple, satisfactory and reliable manner which will result in a rugged tube presenting no serious manufacturing difliculties.
  • a television or like camera tube includes, adjacent the scanned target of .said tube, a mesh structure consisting of two meshes in contact with one another one of which is more lightly tensioned than the other and has an aperture of such size and shape as to accommodate the intended scanning raster of the tube so that when the tube target is scanned in the intended manner the scanning cathode ray encounters only the other mesh.
  • the apertured mesh may be on either side of the other mesh but is preferably on the side thereof remote from the target.
  • the two meshes are carried by a common supporting surround being sandwiched between said surround and a surrounding shim, the meshes, supporting surround and shim being fixed together at and near the outer edge.
  • the two meshes, the supporting surround and the shim are assembled, welded together at and near the outer edge, and then as a unit, heat treated manner known per see to tension the two meshes, the required lesser tensioning of the apertured mesh being obtained by consituting said mesh of slightly heavier material than the other mesh and/or (if the aperture is rectangular (including square) in shapethe usual case) by slightly slitting the apertured mesh at the corners.
  • the aperture is square or rectan-gular-preferably the latterand the two meshes are supported by a surrounding circular support.
  • the diagonal of the aperture should be less than the inner diameter of the circular support in order to reduce liability to the production of standing vibration waves due to vibration wave reflections from the circular support at the corners of the aperture.
  • Suitable materials for the meshes are copper and nickel and, for the support, Nichrome.
  • the invention simple as it is to practice, provides a high degree of immunity from mesh microphony, the apertured mesh providing outwardly of the aperture therein, points of vibration damping contact with the other mesh thus to a large extent, if not entirely, preventing vibra tion and oscillatory movement of said other mesh under shock or external vibratory forces.
  • FIG. 1 which is provided for purposes of explanation and does not itself show the invention, is a simplified representation of a Vidicon
  • FIGS. 2 and 3 which are to a much larger scale than FIG. 1, are mutually perpendicular views showing schematically a mesh structure in accordance with the invention.
  • the Vidicon therein represented includes, within the usual evacuated envelope E, a photoconductive layer P on the inside of the end face plate F of the envelope, a mesh M parallel to and adjacent the layer P, an electrode system including a third grid G3 and an electron gun system G.
  • the mesh M is a simple single mesh supported by a flanged support ring (not separately shown in FIG. 1) in which it is tensioned and the flange of which is fitted into the adjacent open end of G3.
  • a tube is liable to mesh microphony.
  • FIGS. 2 and 3 there is employed in place of the simple single mesh M of FIG. 1, a mesh structure as shown in FIGS. 2 and 3.
  • This comprises two mesh M1 and M2 in contact with one another and sandwiched between a flanged supporting ring M3 and a ring shim M4.
  • the mesh M2 has a central aperture M5 preferably as shown a rectangular apertureeut out of it, this aperture being so dimensioned and shaped as to accommodate fairly closely within it the area through which the cathode ray passes when scanning the target. This area is indicated in FIG. 3 by the broken line rectangle M6.
  • the meshes M2 and M1 are laid flat across the support ring M3 and the shim M4 then put in place to sandwich the meshes between itself and the ring M3.
  • the parts M3, M2, M1 and M4 are then welded together at and near the edges to form a united structure.
  • This structure is then heat treated in manner known per se to tension the meshes, with mesh M2 rather less tensioned than mesh M1. This lesser tensioning can be assured making M2 slightly thicker than M1 and/or by slitting it slightly at the corners as indicated by slits M7.
  • the mesh M1 will be slightly nearer the layer P (when the structure is mounted in the tube) than the mesh M2. This, though not essential, is preferred but, if desired, the mesh M2 would be nearer the layer P than the mesh M1.
  • the invention is also applicable to the target meshes of image orthicontubes to reduce or eliminate microphony therein.
  • a television or like camera tube having adjacent the scanned target of said tube, a mesh structure consisting of two meshes in contact w1th one another, one of which is more lightly tensioned than the other and has an aperture of such size and shape as to accommodate the intended scanning raster of the tube and supporting means for supporting the meshes so that when the tube target is scanned in the intended manner the scanning cathode ray encounters only the other mesh.
  • a tube as claimed in claim 2 wherein said supporting means comprises a common supporting surround, said two meshes being sandwiched between said surround and a surrounding shim, the meshes, supporting surround and shim being fixed together at or near the outer edges of the meshes.

Landscapes

  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Particle Accelerators (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
US396196A 1963-11-13 1964-09-14 Mesh with raster-size aperture for dampening vibrations of camera tube mesh Expired - Lifetime US3320465A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB44751/63A GB1014376A (en) 1963-11-13 1963-11-13 Improvements in or relating to television and like camera cathode ray tubes

Publications (1)

Publication Number Publication Date
US3320465A true US3320465A (en) 1967-05-16

Family

ID=10434592

Family Applications (1)

Application Number Title Priority Date Filing Date
US396196A Expired - Lifetime US3320465A (en) 1963-11-13 1964-09-14 Mesh with raster-size aperture for dampening vibrations of camera tube mesh

Country Status (6)

Country Link
US (1) US3320465A (de)
CH (1) CH431613A (de)
DE (1) DE1230452B (de)
GB (1) GB1014376A (de)
NL (1) NL146978B (de)
SE (1) SE307378B (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3906278A (en) * 1974-10-15 1975-09-16 English Electric Valve Co Ltd Camera tube mesh clamped between dished annular members

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL7214547A (de) * 1972-10-27 1974-05-01

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3035197A (en) * 1958-11-21 1962-05-15 English Electric Valve Co Ltd Television camera tubes
US3249785A (en) * 1963-06-10 1966-05-03 Robert W Floyd Target-screen assembly for television pickup tubes

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL227247A (de) * 1957-05-20
GB851757A (en) * 1957-11-28 1960-10-19 English Electric Valve Co Ltd Improvements in or relating to cathode ray tubes
NL255178A (de) * 1959-08-27
DE1145669B (de) * 1960-06-01 1963-03-21 Fernseh Gmbh Anordnung zur Unterdrueckung der Mikrophonie bei Fernsehaufnahmeroehren

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3035197A (en) * 1958-11-21 1962-05-15 English Electric Valve Co Ltd Television camera tubes
US3249785A (en) * 1963-06-10 1966-05-03 Robert W Floyd Target-screen assembly for television pickup tubes

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3906278A (en) * 1974-10-15 1975-09-16 English Electric Valve Co Ltd Camera tube mesh clamped between dished annular members

Also Published As

Publication number Publication date
NL146978B (nl) 1975-08-15
SE307378B (de) 1969-01-07
NL6412877A (de) 1965-05-14
DE1230452B (de) 1966-12-15
CH431613A (fr) 1967-03-15
GB1014376A (en) 1965-12-22

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