US3364372A - Electrostatic electron lenses with telescopically adjustable tubular elements - Google Patents

Electrostatic electron lenses with telescopically adjustable tubular elements Download PDF

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Publication number
US3364372A
US3364372A US386172A US38617264A US3364372A US 3364372 A US3364372 A US 3364372A US 386172 A US386172 A US 386172A US 38617264 A US38617264 A US 38617264A US 3364372 A US3364372 A US 3364372A
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United States
Prior art keywords
electrode
electrodes
lens
relationship
tubular
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Expired - Lifetime
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US386172A
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English (en)
Inventor
Bennett Maurice Ronald
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
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English Electric Valve Co Ltd
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Publication date
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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
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/82—Mounting, supporting, spacing, or insulating electron-optical or ion-optical arrangements

Definitions

  • the invention relates to electrostatic electron lenses and has particular application in cathode ray tubes.
  • Electrostatic lenses usedin cathode ray tubes generally comprises an Einzel lens, two types of which are shown in section in FIGURES 1 and 2 respectively of the accompanying drawings.
  • the lens shown in FIG. 1 comprises two metal tubular electrodes 1 and 2 of the same diameter coaxially spaced a distance a apart.
  • a third tubular metal electrode 3 coaxially surrounds the gap between the electrodes 1 and 2 and extends a little way over each of those electrodes.
  • the three electrodes are supported in their mutual relationship within the neck of the cathode ray tube (not shown) by wire supports attached to the electrodes, some of the supports being shown at 4.
  • the wire supports are fused into glass support rods distributed around the structure, one of the rods being shown at 5.
  • FIGURE 2 shows a different form of Einzel lens in which there are three co-axial tubular electrodes 7, 8 and 9 of which 7, which is nearest the cathode end 10 of the lens, is of smallest diameter and 9, which is nearest the anode end 11 of the lens is of largest diameter.
  • the electrode 8 is of intermediate diameter and overlaps electrode 7 and is overlapped by electrode 9. Again the interrelationship of the electrodes is maintained Within the cathode ray tube by wire supports 12 fused into glass rods of which one is shown at 13.
  • the largest diameter electrode (3 in FIG. 1; 9 in FIG. 2) is constituted by a conductive coating on the inside of the neck of the cathode ray tube in which case, of course, this particular electrode has no separate support.
  • the distance [2 between the anode end of electrode 7 and the anode end of electrode 8 in FIG. 2, like the distance a in FIGURE 1, is of particular and critical importance in governing the performance of the lens. These distances have to be carefully pro-determined (in most cases to a value in the neighbourhood of half an inch) and a departure of as little as one thousandth of an inch from the predetermined value can result in a substantial alteration of the focal length of the lens. It is therefore of great importance that in the manufacture of the lenses the distances a and b be closely controlled.
  • the lens electrodes with their support wires attached are supported in their intended mutual relationship in a jig and the ends of Wires are immersed in molten glass rods which are then allowed to set to hold the electrodes in place.
  • the present invention seeks to avoid such ditliculty and render the precise control of the more critical spacings of the lenses easier during manufacture.
  • At least one of the tubular electrodes of an electron lens comprising a number of overlapping tubular electrodes is of telescopic construction whereby, after assembly and mounting of the lens electrodes the telescopically constructed electrode or electrodes can be finely adjusted as to the overall length thereof thereby to provide with precision a desired inter-electrode relationship.
  • the relatively movable parts of a telescopically constructed electrode are fixed in relation to one another by spot welding.
  • the heat required to do this is normally insufiicient materially to upset the adjustment.
  • a method of making an electron lens comprising co-axial overlapping tubular electrodes of which at least one is of telescopic construction includes the steps of mounting the electrodes by means including support wires fused into glass orlike support members, adjusting to a desired overall length the telescopically constructed electrode after the electrodes have been assembled and mounted and then fixing the adjustment made.
  • the invention not only gives the great advantage of attainment of accurate effective spacing without disturbance by heat processes used in manufacture but also errors in inter-electrode spacing brought about by failure to have the support wires in precisely the right positions can be substantially eradicated by adjusting the telescopic electrode (or electrodes: more than one can be telescopic) with fine accuracy and then spot-welding or otherwise fixing the telescoping parts when adjustment is complete.
  • the simplest form of telescopically constructed electrode for use in carrying out this invention consists of two parts one of which can be slid over the other.
  • a preferred form of Einzel lens in accordance with this invention and for use in a cathode ray tube comprises three tubular electrodes respectively of three different diameters that at the cathode end being the smallest and that at the anode end the largest and the smallest electrode is of telescopic construction consisting of two parts of which the one nearer the cathode end is fixedly supported and the other, nearer the anode end can be adjusted towards or away from the next larger diameter electrode.
  • the largest diameter electrode is constituted by a conductive coating on the inside of the neck of the cathode ray tube.
  • FIGURE 3 showing an Einzel lens
  • FIGURE 4 showing a jig for making the lens of FIGURE 3.
  • FIG- URE 5 The provision of a conductive coating on the interior of the neck wall of a cathode ray tube to constitute the electrode of largest diameter is shown in FIG- URE 5.
  • FIGURE 3 shows an Einzel lens of the type described with reference to FIGURE 2 and the same reference numerals are used for all corresponding parts of the two figures.
  • the distance from the anode end of electrode 7 to the anode end of electrode 8 is made deliberately longer than the ultimately required distance a making the part 7 shorter than it would be in a comparable known lens.
  • the part 7 is a slidable tubular stainless steel insert 14 which in effect forms part of the electrode and. when the parts 7, 8 and 9 have been assembled and mounted, and have cooled the projection of the insert 14 from the anode end of part 7 is adjusted to result in the required value for the distance 11 as measured from the anode end of insert 14 to the anode end of electrode 8.
  • the insert is then spot welded to the part 7.
  • a weld is indicated at 15.
  • An electrode 25 may be coated on the interior of the neck wall portion 26 as illustrated in FIGURE 5 and the electrode 25 may, of course, correspond to the electrode 9 of largest diameter as shown in FIGURE 3.
  • FIGURE 4 shows a jig suitable for use in assembling the lens structure of FIGURE 3.
  • the jig comprises a support plate 16 having a hole through which is passed a thread ended rod 17. At the end remote from the thread 18 the rod terminates in an enlarged end 19.
  • a sleeve 20 of the same external diameter as the end 19 is mounted on the rod 17 and between the end of the sleeve and a step presented by end 19 is mounted a rubber collar 21. Tightening a wing 22 threaded on thread 13 axially compresses and radially expands the rubber collar 21.
  • a cylindrical block 23 is mounted on the plate 16 and closely surrounds the sleeve 20.
  • a metal collar 24- of accurately known length is a sliding fit on sleeve 20 and abuts against the fiat end of block 23.
  • the insert 14 which is dimensioned to be a sliding fit in part 7, is pushed into it to project from the anode end thereof.
  • the assembly is then mounted on the jig in the manner shown in FIGURE 4 with the insert over the projecting end of the sleeve 20.
  • the wing nut 22 is tightened so that the insert 14 is gripped internally by the expanded rubber collar 21. This allows the insert to be held against twisting if the rest of the assembly is twisted relative to the jig so as to facilitate adjustment of the axial position of the insert in the assembly.
  • the assembly By axial movement (which may be facilitated by twisting) the assembly is mounted on the jig so that the anode end of electrode 8 abuts against the flat end of block 23. Since the anode end of insert 14 abuts against the end of collar 24, the distance b corresponds to the length of the collar 24 which is accurately determined. When in this position the electrode 14 is spot welded at 15 and other points to the electrode 7. The Wing nut 22 is slackened and the assembled structure withdrawn.
  • An Einzel electron lens Comprising a plurality of assembled and mounted separated overlapping tubular lens electrodes of varying diameters and mounting means for supporting said electrodes in coarse predetermined inter-electrode relationship, one of said electrodes being disposed in precisely determined inter-electrode spatial relationship with at least one further of said electrodes, said at least one further electrode including two contacting tubular parts in telescopic relationship and having a precisely fixed over-all length finely adjusted subsequently to the mounting of the electrodes on said mounting means to provide said precisely determined inter-electrode spatial relationship.
  • tubular electrodes comprise three overlapping electrodes of different diameters, said at least one further electrode having the smallest diameter.
  • An electron lens as claimed in claim 1 wherein another of said tubular electrodes comprises a conductively coated inner surface of a cathode ray tube.
  • a cathode ray tube having an envelope comprising an inner wall and an Einzel focussing lens comprising a plurality of assembled and mounted tubular electrodes of different diameters, one of said electrodes being of largest diameter and comprising a conductive coating on said inner wall, mounting means for supporting the remaining electrodes in coarse predetermined electrode spatial rela* tionship, one of said plurality of electrodes being disposed in precisely determined inter-electrode spatial relationship with at least one further of said plurality of electrodes, said at least one further of said electrodes including-two contacting tubular parts in telescopic relationship and having a precisely fixed over-all length adjusted subsequently to the mounting of the electrodes on said mounting means to provide said precisely determined inter-elem trode spatial relationship.

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  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
  • Electrolytic Production Of Metals (AREA)
  • Dot-Matrix Printers And Others (AREA)
US386172A 1963-08-14 1964-07-30 Electrostatic electron lenses with telescopically adjustable tubular elements Expired - Lifetime US3364372A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3212163 1963-08-14

Publications (1)

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US3364372A true US3364372A (en) 1968-01-16

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US386172A Expired - Lifetime US3364372A (en) 1963-08-14 1964-07-30 Electrostatic electron lenses with telescopically adjustable tubular elements

Country Status (6)

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US (1) US3364372A (xx)
CH (1) CH455946A (xx)
DE (1) DE1464899A1 (xx)
GB (1) GB1047337A (xx)
NL (1) NL6409269A (xx)
SE (1) SE316241B (xx)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5114216A (ja) * 1974-07-26 1976-02-04 Hitachi Ltd Seidenshusokugatasatsuzokan
US4169239A (en) * 1974-07-26 1979-09-25 Hitachi, Ltd. Electrostatically focusing type image pickup tubes and method of manufacturing the same

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2174853A (en) * 1937-08-26 1939-10-03 Hygrade Sylvania Corp Electron gun structure and method of assembly thereof
US2567674A (en) * 1949-11-08 1951-09-11 Rca Corp Velocity modulated electron discharge device
US2720606A (en) * 1953-12-23 1955-10-11 Rca Corp Electron microscopy
DE968869C (de) * 1948-12-24 1958-04-03 Siemens Ag Anordnung zur Vermeidung von Korrosionen an dem Kuehlmittelleitungsanschluss einanodischen Charakters eines elektrischen Entladungsgefaesses mit metallischem Mantel
US2935642A (en) * 1957-07-22 1960-05-03 Rca Corp Electron gun
US2942128A (en) * 1958-05-28 1960-06-21 Johnson And Hoffman Mfg Corp Electrodes for electron gun unit
US3082342A (en) * 1959-02-11 1963-03-19 Philips Corp Photo-electric tube

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2174853A (en) * 1937-08-26 1939-10-03 Hygrade Sylvania Corp Electron gun structure and method of assembly thereof
DE968869C (de) * 1948-12-24 1958-04-03 Siemens Ag Anordnung zur Vermeidung von Korrosionen an dem Kuehlmittelleitungsanschluss einanodischen Charakters eines elektrischen Entladungsgefaesses mit metallischem Mantel
US2567674A (en) * 1949-11-08 1951-09-11 Rca Corp Velocity modulated electron discharge device
US2720606A (en) * 1953-12-23 1955-10-11 Rca Corp Electron microscopy
US2935642A (en) * 1957-07-22 1960-05-03 Rca Corp Electron gun
US2942128A (en) * 1958-05-28 1960-06-21 Johnson And Hoffman Mfg Corp Electrodes for electron gun unit
US3082342A (en) * 1959-02-11 1963-03-19 Philips Corp Photo-electric tube

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5114216A (ja) * 1974-07-26 1976-02-04 Hitachi Ltd Seidenshusokugatasatsuzokan
JPS5419129B2 (xx) * 1974-07-26 1979-07-12
US4169239A (en) * 1974-07-26 1979-09-25 Hitachi, Ltd. Electrostatically focusing type image pickup tubes and method of manufacturing the same

Also Published As

Publication number Publication date
NL6409269A (xx) 1965-02-15
SE316241B (xx) 1969-10-20
GB1047337A (xx)
CH455946A (fr) 1968-05-15
DE1464899A1 (de) 1970-05-27

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