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US3354340A - Cap-shaped control electrode securing cathode by thin supporting members - Google Patents

Cap-shaped control electrode securing cathode by thin supporting members Download PDF

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Publication number
US3354340A
US3354340A US591367A US59136766A US3354340A US 3354340 A US3354340 A US 3354340A US 591367 A US591367 A US 591367A US 59136766 A US59136766 A US 59136766A US 3354340 A US3354340 A US 3354340A
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US
United States
Prior art keywords
cathode
control electrode
secured
cylinder
supporting
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
US591367A
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English (en)
Inventor
Almer Friedrich Herman Raymund
Schrijnemakers Gerardus Marie
Kuiper Adrianus
Alphonsus Petrus Van Rooy
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.)
US Philips Corp
North American Philips Co Inc
Original Assignee
US Philips Corp
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 US Philips Corp filed Critical US Philips Corp
Application granted granted Critical
Publication of US3354340A publication Critical patent/US3354340A/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
    • H01J3/00—Details of electron-optical or ion-optical arrangements or of ion traps common to two or more basic types of discharge tubes or lamps
    • H01J3/02—Electron guns
    • H01J3/027—Construction of the gun or parts 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
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/48—Electron guns
    • H01J29/485—Construction of the gun or of parts thereof

Definitions

  • a quick heating narrow tolerance, easily manufactured electron source for a cathode-ray tube comprising a perforated, cap-shaped control electrode in which a cylindrical cathode having an emissive end surface is secured by a plurality of thin supporting members, a supporting cylinder, an annular insulating body, and an annular metal body which is secured to the cap-shaped control electrode.
  • This invention relates to an electron source for an electron gun, comprising a perforated, cap-shaped control electrode in which a cylindrical cathode having an emissive end surface is secured by means of a plurality of thin supporting members, a supporting cylinder, an insulating body in the form of a cylindrical ring, and an annular metal body which is secured to the control electrode.
  • a construction which is advantageous in every respect is obtained for such an electron gun comprising a perforated cap-shaped control electrode in which a cylindrical cathode having an emissive end surface is secured by means of a plurality of supporting members, a supporting cylinder, an insulating body in the form of a cylindrical ring, and an annular metal body which is secured to the control electrode if, according to the invention, the outer'cylindrical face of the insulating body is connected to the annular metal body and its inner cylindrical face is secured to the supporting cylinder by means of a substance fused thereon, the ends of the supporting cylinder projecting from the insulating body and the supporting members of the cathode being secured to the cathode support and to a flange provided on the end of the supporting cylinder adjacent the emissive surface of the cathode, while the annular metal body also being secured to a plurality of tongues recessed in the cylindrical wall of the control electrode.
  • the insulating body may advantageously comprise a body of prepressed glass which may be secured by fusion to both the supporting cylinder and the annular metal body.
  • the connection to the metal ring is preferably obtained by pressure-welding.
  • an insulator made of crystallized glass or fusible ceramic material composed of, for example, a mixture of 50% by weight of A1 0 and 50% by weight of a mixture consisting of equal parts by weight of CaO and B203.
  • the insulating ring will have to be made of crystallized glass or ceramic material.
  • the said construction affords the advantage that the cylindrical faces only of the ceramic insulator and hence not part of its upper and/ or lower surfaces must be metallized for soldering said faces to the supporting cylinder and the metal ring respectively.
  • the end-faces of the insulating ring may be deprived of any metal deposited thereon by merely grinding it flat.
  • a plurality of supporting rods for securing the heating body may be sealed or soldered in the insulating ring.
  • FIGURE 1 is a sectional view of one embodiment of an electron source according to the invention.
  • FIGURE 2 shows another embodiment of a cathode construction according to the invention
  • FIGURE 3 shows another mode of connection of the insulator and the supporting cylinder
  • FIGURE 4 is a developed view of the material forming the control electrode.
  • reference numeral 1 indicates the cathode Which is secured in a cap-like control electrode 2 by means of three thin supporting strips 3 welded to a flange 14 of a supporting cylinder 4.
  • the supporting cylinder 4 is sealed in an insulating cylindrical ring 5, the cylindrical outer face of which is connected, by fusion or by so-called pressure-welding to an annular metal body 6, which, following the adjustment of the correct distance of cathode 1 relative to control electrode 2, is Welded to strips 7, recessed in a cylindrical side-wall 18 of control electrode 2.
  • the said cathode-control electrode distance is preferably adjusted by adjusting the capacitance of cathode 1 relative to a first anode 21, as is known per se.
  • the shielding of the cathode relative to the first anode which is thus required is obtained by clamping the ring 6 on a welding electrode (not shown) which is formed as a hollow cylinder housing the insulated resilient member which may make contact with the lower end of supporting cylinder 4.
  • the correct cathode to control electrode distance is adjusted by displacing the electron gun relative to the cathode 1.
  • the ring 6 is welded to the strips 7. Since the strips 7 are slightly resilient the distance between the cathode 1 and the control electrode 2 is prevented from being influenced during the welding operation.
  • the cathode 1 has a cap-like support, the emissive layer being present on the closed end surface.
  • the support comprises a cathode cylinder 8 which serves as an envelope for a heating body 9.
  • the cathode cylinder 8 does not serve as a structural element, since the supporting strips 3 of the cathode are Welded to the cathode support 4 itself.
  • the cathode cylinder 8 may therefore be made of thin material so that the heat content may be small and a short heating-up time is obtained.
  • the heating element is substantially concentrated adjacent the closed end of the cathode and hence near its emissive surface, in which event a very small wall thickness (even less than 25p) may be used since the heat conduction of the cylinder is then less important.
  • the heating element due to the small dimensions of the cathode a 1, it is in general impossible for the heating element to be arranged entirely within the cathode cap, although the construction of the heating element may be such that most of the heat is evolved close to the emissive layer.
  • the cathode cylinder 8 Since the length of the cathode cylinder 8 has no function at all, in structural respect it may be varied so that different heating energies can be used. In fact, the cathode cylinder has the task not only to envelop the heating element, but also to reduce the heating-up time of the cathode, the cathode reaching its emission temperature when the heating element is concentrated in it, much sooner than the cylinder 8 which then receives its heat substantially through conduction from the cathode support 1. After the cathode is already emitting electrons the temperature of cylinder 8 increases so that the radiation towards the supporting cylinder 4 increases and hence the thermal losses increase and excessive heating of the cathode is avoided.
  • An even shorter heating-up time of the emissive layer may be obtained by reducing the length and hence the mass of the cathode support, as shown in FIGURE 2.
  • the radiating surface thus becomes too small for preventing excessive heating of the cathode.
  • This may be compensated for by blackening the outer surface of cathode cylinder 8 and possibly also of cathode support 1, so that eventually the same amount of energy is radiated. In this case, preferably the inner side of supporting cylinder 4 is also blackened.
  • the cathode cylinder 8 within the supporting cap emerges into at least two, preferably three, narrow tongues the ends of which are secured by welding, at 20, inside the. cathode support 1 closely below the upper face thereof. Consequently, a larger part of the inner surface of cathode support 1 is radiated directly by the heating body 9, while the tongues of the cathode cylinder are also warmed up, resulting in the heat dissipation from the support 1 through the welding areas of said tongues to the part of cathode cylinder 8 projecting below the cathode being retarded. Thus, the emissive end surface of the cathode soon reaches the operating temperature.
  • the open end of the cathode support 1 is provided with a flange for obtaining greater rigidity. Furthermore, the supporting strips 3 of the cathode may be welded to the said cathode flange. It has been found that, if the angle made by the strips 3 with the surface of a flange 14 on supporting cylinder 4 is chosen suitably, also in connection with the coefficients of thermal expansion of the cathode support 1, the control electrode 2, the strips 3 and the supporting cylinder 4, not only the displacement of the emissive surface relative to the control electrode 2 can be maintained very small in a large range of different temperaturesfbut also the influence of the mechanical tolerances in the manufacture of these various parts exerted on the cathode-to-control electrode distance may, be reduced substantially to zero.
  • the optimum angle will generally be comprised between and 60.
  • the strips 3 must then be formed so that they can bend during the heating-up of the cathode and with strong variations in temperature, only near the points of bending adjacent the flanges to which they are secured. To this end, the strips are strengthened, between their points of bending by meansof impressed grooves or the like.
  • the strips 3 may alternatively have the form of thin rods depressed slightly at the points of bending in order to reduce the rigidity at these areas so thatbending during the expansion of the various component parts will occur in situ.
  • the latter are made of hard material, such as nickel-iron and nickel-iron-molybdenum compounds, so that they can be thin while having the required strength.
  • the cathode-to-control electrode distance in an electron source of the described composition remains substantially constant, the said distance may be made very small without the cathode being liable to contact the control electrode during the rapid and strong heating on de' gassing the electrodes in the cathode-ray tube.
  • the heat radiated by the cathode cylinder 8 is collected and reflected by the supporting cylinder 4 which reaches a comparatively high temperature.
  • the cylinder 4 may consist of an alloy of a low coefficient of, expansion, such as fernico, which can be sealed in glass and is also a comparatively poor thermal conductor. Since the cylinder 4 contacts the insulating ring 5 only over a small part of its length, the dissipation of heat to the insulating material maybe small. If desired, the heat con duction may be reduced further by means of recesses in the annular inner surface of the insulator 5 so that it is not connected to the supporting cylinder 4 throughout its periphery, as shown in FIGURE 3. Due to the poor heat conduction of the material forming the cylinder 4, the end 15 thereof which projects from the insulator 5 assumes a high temperature owing to the heat radiation from the cathode 1, so that the supporting members 3 cause only a low thermal loss.
  • the supporting cylinder 4 also acts as a screen for metal vapour which might deposit from the cathode 1 and the cathode cylinder 8 onto the insulator 5. Furthermore, the supporting cylinder 4 ensures that during the final assembly, that is during all the remaining assembling operations on the electron gun after the ring 6 has been secured to the control electrode 2, the cathode cylinder 8 is not touched which would involve the risk that the adjustment of the cathode might be modified.
  • the clasp 11 substantially has the shape of an M the limbs of which become aligned with the supporting rods 10 so that the clasp 11 may be wholly enclosed in the above-described hollow welding electrode during the ca pacitive adjustment of the cathode-to-control electrode distance.
  • the parts of the clasp 11 are welded through the tongues 12 to current-supply pins sealed in a base part.
  • the tongues 12 may be bent over, if necessary, without the adjustment of the heating body in the cathode being influenced thereby.
  • the supporting cylinder 4 is provided with a current supply conductor 13 for the cathode.
  • the thermal contact obtained is reproducible so that little differences in the temperatures of different cathodes occur. This is also the case if the insulating part 5 is made of ceramic material since the connection to the metal cylinder 4 is then obtained :by soldering. Also, the dissipation of heat from the insulating body 5 through a pressure weld to the annular body 6 is satisfactorily reproducible.
  • the control electrode 2 may be manufactured in a very simple manner from a metal plate shaped into the form shown in FIGURE 4. When this plate is pushed through a cylindrical template, a cap-shaped electrode results having its cylindrical side-wall formed by parts 18 and the tongues 7.
  • the invention provides an electron source for an electron gun which may have a very small working distance between cathode and control electrode, which has a very stable operation independent of variations in temperature, which is mechanically rigid and resistant to shocks, which has a very low tendency to cause microphonic interference and which can be manufactured in a very simple manner and at low cost since mechanical tolerances exert only small influence on the adjustment.
  • An electron source for an electron gun comprising a perforated, cap-shaped control electrode in which a cylindrical cathode having an emissive end surface is secured by means of a plurality of thin supporting members, a supporting cylinder, an insulating body in the form of a cylindrical ring, and an annular metal body which is secured to the control electrode, characterized in that the outer cylindrical face of the insulating body is connected to the annular metal body and its inner cylindrical face is secured to the supporting cylinder by means of a substance fused thereon, the ends of the supporting cylinder projecting from the insulating body and the supporting members of the cathode being secured to the cathode support and to a flange provided on the end of the supporting cylinder adjacent the emissive surface of the cathode, while the annular metal body being secured to a plurality of tongues recessed in the cylindrical Wall of the control electrode.
  • An electron source as claimed in claim 1 characterized in that the insulating body consists of crystallized glass.
  • An electron source as claimed in claim 1 characterized in that the inner annular surface of the insulating body is provided with recesses, so that the said surface is secured to he supporting cylinder only over part of the periphery thereof.
  • An electron source as claimed in claim 1 characterized in that a plurality of supporting rods for the ends of the heating wire are secured in the insulating body.
  • An electron source as claimed in claim 1 characterized in that the two ends of the supporting cylinder project from the insulating body, the end of the supporting cylinder adjacent the emissive surface of the cathode being provided with a flange to which the ends of the supporting members of the cathode are welded.
  • An electron source as claimed in claim 1 characterized in that the supporting members of the cathode are secured to a flange on the open end of the cap-shaped cathode support itself.
  • An electron source as claimed in claim 1 characterized in that the cathode cylinder inside the cap-shaped cathode support merges into at least two tongues the ends of which are welded to the inner surface of the said sup port, the heating element being concentrated substantially near the closed end of the cathode.
  • An electron source as claimed in claim 1 characterized in that the wall thickness of the cathode cylinder is less than 25 1, the heating element being concentrated substantially near the closed end of the cathode.
  • An electron source as claimed in claim 13 characterized in that at least one of the outer surfaces of the cathode cylinder, of the cathode support and the inner surface of the supporting cylinder are blackened.
  • annular metallic :body is welded to tongues formed in the cylindrical side-wall of the cupshaped control electrode.

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  • Electrodes For Cathode-Ray Tubes (AREA)
  • Electron Sources, Ion Sources (AREA)
US591367A 1965-10-22 1966-10-14 Cap-shaped control electrode securing cathode by thin supporting members Expired - Lifetime US3354340A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL6513665A NL6513665A (de) 1965-10-22 1965-10-22

Publications (1)

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US3354340A true US3354340A (en) 1967-11-21

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US591367A Expired - Lifetime US3354340A (en) 1965-10-22 1966-10-14 Cap-shaped control electrode securing cathode by thin supporting members

Country Status (9)

Country Link
US (1) US3354340A (de)
AT (1) AT261691B (de)
BE (1) BE688801A (de)
CH (1) CH458549A (de)
DE (1) DE1564462C3 (de)
ES (1) ES332473A1 (de)
FR (1) FR1504694A (de)
GB (1) GB1113748A (de)
NL (1) NL6513665A (de)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3569768A (en) * 1968-11-21 1971-03-09 Sylvania Electric Prod Cathode sleeve effecting maximum heat transfer to top of cathode cap and minimum to cap wall
JPS50120564A (de) * 1974-02-22 1975-09-20
US3955114A (en) * 1973-07-10 1976-05-04 International Standard Electric Corporation Magnetically focused electron beam tube
US3979631A (en) * 1974-04-25 1976-09-07 U.S. Philips Corporation Cathode ray tube with electrostatic multipole focusing lens
US4057746A (en) * 1975-06-23 1977-11-08 Sciaky Vitry, S. A. Demountable high power electron beam gun
DE2642582A1 (de) * 1976-09-22 1978-03-23 Licentia Gmbh Kathodenstrahlroehre
FR2481516A1 (de) * 1980-04-23 1981-10-30 Philips Nv
US4516051A (en) * 1981-11-18 1985-05-07 U.S. Philips Corporation Cathode-ray tube and cathode unit for such a cathode-ray tube
US4554480A (en) * 1983-11-29 1985-11-19 Rca Corporation Cathode-ray tube having an electron gun assembly with emissivity modifying means
EP0072588B1 (de) * 1981-08-14 1985-12-11 Koninklijke Philips Electronics N.V. Kathodenstrahlröhre
US5289076A (en) * 1990-12-24 1994-02-22 Goldstar Co. Ltd. Cathode structure for a cathode ray tube
US5767615A (en) * 1993-07-19 1998-06-16 Sony Corporation Electron gun for a cathode ray tube
NL2015039A (en) * 2013-12-30 2015-07-09 Mapper Lithography Ip Bv Focusing electrode for cathode arrangement, electron gun, and lithography system comprising such electron gun.
US9455112B2 (en) 2013-12-30 2016-09-27 Mapper Lithography Ip B.V. Cathode arrangement, electron gun, and lithography system comprising such electron gun

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2313911B2 (de) * 1973-03-20 1975-09-25 Standard Elektrik Lorenz Ag, 7000 Stuttgart Schnell anheizende Kathode für Kathodenstrahlröhren
DE2541886C2 (de) * 1974-09-19 1983-01-13 Tokyo Shibaura Electric Co., Ltd., Kawasaki, Kanagawa Elektronenstrahlerzeugungsanordnung mit mindestens einer Elektronenkanoneneinheit
DE2642560C2 (de) * 1976-09-22 1983-08-04 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Farbbildkathodenstrahlröhre
DE2734869C2 (de) * 1977-08-03 1982-09-02 Standard Elektrik Lorenz Ag, 7000 Stuttgart Heizeranschlußbügel für Kathodenstrahlröhren
JPS6036056B2 (ja) * 1979-06-21 1985-08-17 株式会社東芝 陰極構体
DE2938248A1 (de) * 1979-09-21 1981-03-26 Standard Elektrik Lorenz AG, 70435 Stuttgart Heizelement fuer eine indirekt geheizte kathode

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2833952A (en) * 1955-10-14 1958-05-06 Sylvania Electric Prod Cathode ray tube electrode assembly
US3155865A (en) * 1961-12-15 1964-11-03 Gen Electric Low power heater

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2833952A (en) * 1955-10-14 1958-05-06 Sylvania Electric Prod Cathode ray tube electrode assembly
US3155865A (en) * 1961-12-15 1964-11-03 Gen Electric Low power heater

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3569768A (en) * 1968-11-21 1971-03-09 Sylvania Electric Prod Cathode sleeve effecting maximum heat transfer to top of cathode cap and minimum to cap wall
US3955114A (en) * 1973-07-10 1976-05-04 International Standard Electric Corporation Magnetically focused electron beam tube
JPS50120564A (de) * 1974-02-22 1975-09-20
US3973161A (en) * 1974-02-22 1976-08-03 U.S. Philips Corporation Plural gun cathode-ray tube with oval control electrodes
US3979631A (en) * 1974-04-25 1976-09-07 U.S. Philips Corporation Cathode ray tube with electrostatic multipole focusing lens
US4057746A (en) * 1975-06-23 1977-11-08 Sciaky Vitry, S. A. Demountable high power electron beam gun
DE2642582A1 (de) * 1976-09-22 1978-03-23 Licentia Gmbh Kathodenstrahlroehre
FR2481516A1 (de) * 1980-04-23 1981-10-30 Philips Nv
EP0072588B1 (de) * 1981-08-14 1985-12-11 Koninklijke Philips Electronics N.V. Kathodenstrahlröhre
US4516051A (en) * 1981-11-18 1985-05-07 U.S. Philips Corporation Cathode-ray tube and cathode unit for such a cathode-ray tube
US4554480A (en) * 1983-11-29 1985-11-19 Rca Corporation Cathode-ray tube having an electron gun assembly with emissivity modifying means
US5289076A (en) * 1990-12-24 1994-02-22 Goldstar Co. Ltd. Cathode structure for a cathode ray tube
US5767615A (en) * 1993-07-19 1998-06-16 Sony Corporation Electron gun for a cathode ray tube
NL2015039A (en) * 2013-12-30 2015-07-09 Mapper Lithography Ip Bv Focusing electrode for cathode arrangement, electron gun, and lithography system comprising such electron gun.
US9455112B2 (en) 2013-12-30 2016-09-27 Mapper Lithography Ip B.V. Cathode arrangement, electron gun, and lithography system comprising such electron gun
US9466453B2 (en) 2013-12-30 2016-10-11 Mapper Lithography Ip B.V. Cathode arrangement, electron gun, and lithography system comprising such electron gun
EP3090438B1 (de) * 2013-12-30 2020-03-25 ASML Netherlands B.V. Kathodenanordnung, elektronenkanone und lithografiesystem mit solch einer elektronenkanone
US10622188B2 (en) 2013-12-30 2020-04-14 Asml Netherlands B.V. Focusing electrode for cathode arrangement, electron gun, and lithography system comprising such electron gun

Also Published As

Publication number Publication date
ES332473A1 (es) 1967-10-16
AT261691B (de) 1968-05-10
DE1564462A1 (de) 1970-01-22
FR1504694A (fr) 1967-12-08
DE1564462C3 (de) 1978-10-05
DE1564462B2 (de) 1978-02-02
NL6513665A (de) 1967-04-24
CH458549A (de) 1968-06-30
BE688801A (de) 1967-04-24
GB1113748A (en) 1968-05-15

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