US2923843A - Cathode ray tubes - Google Patents

Cathode ray tubes Download PDF

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Publication number
US2923843A
US2923843A US727889A US72788958A US2923843A US 2923843 A US2923843 A US 2923843A US 727889 A US727889 A US 727889A US 72788958 A US72788958 A US 72788958A US 2923843 A US2923843 A US 2923843A
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US
United States
Prior art keywords
mesh
spacers
spacer
target structure
strip
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
US727889A
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English (en)
Inventor
Turk Walter Ernest
Hendry Eric Douglas
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 US2923843A publication Critical patent/US2923843A/en
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
    • 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
    • H01J29/026—Mounting or supporting arrangements for charge storage screens not deposited on the frontplate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/26—Image pick-up tubes having an input of visible light and electric output
    • H01J31/28—Image pick-up tubes having an input of visible light and electric output with electron ray scanning the image screen

Definitions

  • This invention relates to cathode ray tubes and more specifically to video signal generating tubes of the kind in which video signals are obtained by scanning with a cathode ray a target structure in which a high resistance electric charge storing plate is mounted in close juxtaposition to but spaced and insulated from a grid or mesh.
  • Well known examples of tubes of this kind are television camera tubes such as the well known image orthicon tube.
  • a trouble frequently encountered with image orthicon and other tubes of the kind referred to is that of microphony caused by relative movement between the storage plate and the adjacent mesh. Such relative movement produces variation of effective capacitance with corresponding variation in picture signal output level.
  • the movement is commonly of the mechanical resonant type and resonant vibrations are often excited by relatively small mechanical shocks orvibrations. The effect is similar to microphony in thermionic valves.
  • Microphony in cathode ray tubes of the kind referred to may occur in any of the tubes in practical use today, but it is obviously most apt to occur in tubes having larger diameter target structures than in others.
  • the storage plate which is normally a thin membrane-like member of glass, is spaced from the mesh by an annular spacer or washer at the edge and between the two, the three parts-plate, spacer and mesh-being clamped together with the spacer in the middle of the sandwic
  • An improvement as respects microphony can be achieved by replacing such'an annular spacer by a pair of strip-like spacers which are arranged as chords to the normally circular form of the target structure.
  • the present invention seeks to provide improved tubes of the kind referred to which shall have good anti-microphonic qualities and be relatively easily manufacturable closely to a pre-determined design.
  • the target structure of a v tube of the kindV referred to comprises a high resistance charge storage plate positioned adjacent to but spaced from a mesh or grid by spacer means extending across the target structure and xed to a member which also ice serves as the support member for the grid or mesh and to which said grid or mesh is also fixed.
  • the spacer means are of double construction consisting of two parts of low thermal expansion material one on top of the other and fixed together (as well as to the support for the grid or mesh) at the ends. It is found that with this double construction of spacer very good anti-microphonic qualities are indeed obtained.
  • Fig. 1 is a purely schematic representation of an image orthicon tube as a Whole
  • Fig. 2 is a face view of a preferred form of target structure in accordance with this invention.
  • Fig. 3 is a sectional elevation showing, to a considerably larger scale than is used in Fig. 2, the detailed construction of the edge of the target structure;
  • Fig. 4 is a View similar to Fig. 2 but with certain parts omitted for simplicity, and showing a modified arrangement of spacer strips;
  • Fig. 5 is a view similar to Fig. 4 but showing a further modification of the spacer strip arrangement.
  • the tube therein represented is of well known general kind and comprises within the bulbous end of an evacuated envelope E (shown broken away) a photo-cathode P on the end wall of the tube, an accelerator electrode A, a target structure T carried in the customary cylindroconical frame TF, a field mesh electrode F which serves, when the tube is in use, to ensure a uniform electro-static field, and a decelerator electrode D.
  • the present invention is concerned with the construction of the target structure T which is purely schematically represented in Fig. 1.
  • the target structure comprises a tine wire mesh or grid 1, which is stretched across the aperture of a mesh support ring 2, the edge of the circle of mesh being held in a recess in the support ring 2 by means of a hat ring 3 which is welded to the face of the recess and holds the edge of the circle of mesh firmly in place.
  • the mesh is strained liat across the aperture of the support ring 2 by being tensioned over the corner 4 of that ring ⁇ as clearly shown in Fig. 3.
  • Parallel to and spaced from the mesh 1 is a high resistance glass charge plate 7 which is fixed at its circular edge to a so-called target sealing cranked ring 8 to which the glass is sealed.
  • the required spacing between the mesh 1 and the target plate 7 is obtained by means of a pair of strip-like spacers arranged as chords to the target structure (see Fig. 2) and each of double construction comprising two layers of low thermal expansion material one on top of the other.
  • the two layers composing each strip are shown at 5 and 6 in Fig. 3 and are welded at their ends to one another, the lower layer 5 (or both layers 5 and 6) being welded to a fiat annular surface provided on the support ring 2 outwardly of the clamp ring 3.
  • the parts when assembled as shown in Fig. 3 are held together by means of a so-called backing or outer clamp ring 9 which is formed with lugs -10-four such lugs are shown in Fig. 2-which are, as the last stage in the assembly, bent out of the plane of Fig. 2 and then over the free edge of the member 8 so as to form hooklike portions as shown at in Fig. 3 and which hold the assembled parts together.
  • the mesh 1 and glass 7 which of course extend right across the central aperture of the target structure, are treated as though one could see through them both, and the references 1 and 7 are both applied to the central aperture of the target structure while the inner edge of the mesh support ring 2 and the corner 4 of that ring are both shown as circles.
  • the backing ring 9 is also formed with a pair of hooks 11 (not shown in Fig. 3) which serve the usual purpose of facilitating support of the target structure in position in the tube.
  • FIG. 4 The construction shown in Fig. 4 is similar to that shown in Figs. 2 and 3 with the exception that the spacer that shown in Figs. 2 and 3, dilering therefrom however,
  • spacer means comprise a spacer in the shape of a rectangular frame with its corners fixed to the mesh support member.
  • spacer means comprise four separate strip spacers lying along the sides of an imaginary rectangle but forming an incomplete rectangle, the ends of said strip spacers being fixed to the mesh support member.

Landscapes

  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
US727889A 1957-05-20 1958-04-11 Cathode ray tubes Expired - Lifetime US2923843A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB15925/57A GB831444A (en) 1957-05-20 1957-05-20 Improvements in or relating to cathode ray tubes

Publications (1)

Publication Number Publication Date
US2923843A true US2923843A (en) 1960-02-02

Family

ID=10068018

Family Applications (1)

Application Number Title Priority Date Filing Date
US727889A Expired - Lifetime US2923843A (en) 1957-05-20 1958-04-11 Cathode ray tubes

Country Status (5)

Country Link
US (1) US2923843A (enrdf_load_stackoverflow)
DE (1) DE1063202B (enrdf_load_stackoverflow)
FR (1) FR1203845A (enrdf_load_stackoverflow)
GB (1) GB831444A (enrdf_load_stackoverflow)
NL (1) NL227247A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3160773A (en) * 1962-01-15 1964-12-08 Westinghouse Electric Corp Direct viewing storage tubes having ceramic spacers between collector electrode and storage grid
US3207937A (en) * 1960-05-19 1965-09-21 Gen Electric Thin film storage electrode
US3229141A (en) * 1959-08-27 1966-01-11 English Electric Valve Co Ltd Television camera tube storage plate with rectangular stiffening ridge
US3249785A (en) * 1963-06-10 1966-05-03 Robert W Floyd Target-screen assembly for television pickup tubes
US3445707A (en) * 1967-11-13 1969-05-20 Ibm Mica membrane mounting structure for cathode-ray storage tube

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB851757A (en) 1957-11-28 1960-10-19 English Electric Valve Co Ltd Improvements in or relating to cathode ray tubes
NL245593A (enrdf_load_stackoverflow) 1958-11-21
DE1145669B (de) * 1960-06-01 1963-03-21 Fernseh Gmbh Anordnung zur Unterdrueckung der Mikrophonie bei Fernsehaufnahmeroehren
GB1038765A (en) * 1962-05-04 1966-08-10 Electrical & Musical Ind Ltd Improvements relating to television or like pick-up tubes
GB1014376A (en) * 1963-11-13 1965-12-22 English Electric Valve Co Ltd Improvements in or relating to television and like camera cathode ray tubes

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2563488A (en) * 1951-08-07 Barrier grid storage tube
US2582843A (en) * 1948-08-27 1952-01-15 Rca Corp Contact spaced target-mesh assembly for television pickup tubes

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2563488A (en) * 1951-08-07 Barrier grid storage tube
US2582843A (en) * 1948-08-27 1952-01-15 Rca Corp Contact spaced target-mesh assembly for television pickup tubes

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3229141A (en) * 1959-08-27 1966-01-11 English Electric Valve Co Ltd Television camera tube storage plate with rectangular stiffening ridge
US3207937A (en) * 1960-05-19 1965-09-21 Gen Electric Thin film storage electrode
US3160773A (en) * 1962-01-15 1964-12-08 Westinghouse Electric Corp Direct viewing storage tubes having ceramic spacers between collector electrode and storage grid
US3249785A (en) * 1963-06-10 1966-05-03 Robert W Floyd Target-screen assembly for television pickup tubes
US3445707A (en) * 1967-11-13 1969-05-20 Ibm Mica membrane mounting structure for cathode-ray storage tube

Also Published As

Publication number Publication date
FR1203845A (fr) 1960-01-21
GB831444A (en) 1960-03-30
DE1063202B (de) 1959-08-13
NL227247A (enrdf_load_stackoverflow)

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