US3582175A - Method of sealing an electron tube - Google Patents

Method of sealing an electron tube Download PDF

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Publication number
US3582175A
US3582175A US830439A US3582175DA US3582175A US 3582175 A US3582175 A US 3582175A US 830439 A US830439 A US 830439A US 3582175D A US3582175D A US 3582175DA US 3582175 A US3582175 A US 3582175A
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US
United States
Prior art keywords
envelope
alkali
halide
tube
backplate
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
US830439A
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English (en)
Inventor
Yoshihiro Uno
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.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial 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 Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Application granted granted Critical
Publication of US3582175A publication Critical patent/US3582175A/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
    • 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
    • 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
    • H01J29/14—Screens on or from which an image or pattern is formed, picked up, converted or stored acting by discoloration, e.g. halide screen
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J5/00—Details relating to vessels or to leading-in conductors common to two or more basic types of discharge tubes or lamps
    • H01J5/20—Seals between parts of vessels
    • H01J5/22—Vacuum-tight joints between parts of vessel
    • H01J5/24—Vacuum-tight joints between parts of vessel between insulating parts of vessel
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/20—Manufacture of screens on or from which an image or pattern is formed, picked up, converted or stored; Applying coatings to the vessel
    • H01J9/233—Manufacture of photoelectric screens or charge-storage screens
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/24—Manufacture or joining of vessels, leading-in conductors or bases
    • H01J9/26—Sealing together parts of vessels
    • H01J9/263—Sealing together parts of vessels specially adapted for cathode-ray tubes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00—Discharge tubes and lamps
    • H01J2893/0033—Vacuum connection techniques applicable to discharge tubes and lamps
    • H01J2893/0037—Solid sealing members other than lamp bases
    • H01J2893/0038—Direct connection between two insulating elements, in particular via glass material
    • H01J2893/0039—Glass-to-glass connection, e.g. by soldering

Definitions

  • ABSTRACT Method of sealing an electron tube, which is a storage tube for example, having an evaporated alkalihalide layer formed fast on the inner face of the back plate of the tube.
  • the envelope of the tube is previously divided into two pieces so as to facilitate the evaporation of the alkali-halide crystals and thus must be sealed upon completion of the evaporation.
  • the envelope is sealed by application thereto of heat with another heat simultaneously applied to the alkali-halide layer, thus prohibiting the layer from becoming wet.
  • This invention is concerned with method of fabricating an electron tube using an evaporated alkali-halide plate and, more particularly, it relates to an improved method of sealing off the envelope of the electron tube with the alkali-halide plate kept concurrently heated at a high temperature.
  • Typical of the electron tubes using an alkali-halide plate are the secondary electron multiplier tube and image intensifier tube, in which are utilized the specific characteristics of the evaporated alkali-halide which acts as a secondary-electronemissive surface with high quality. If the surface of the alkalihalide crystals is irradiated with electron beams, as is well known, an optical absorption band (F-band) which is usually referred to as an F-center is induced in the crystals. This phenomenon lends itself to the storage of optical information and is often utilized to constitute an image storage tube. In the following description, therefore, the electron tubes using an evaporated alkali-halide plate are exemplified in the imagestorage tube for simplicity of discussion, although the electron tubes of such type find a variety of other practically useful applications.
  • F-band optical absorption band
  • FIGS. 1 to 3 are views illustrating different manners of evaporating the alkali-halide crystals and sealing off the tube envelope as heretofore put into practice;
  • FIG. 4 is a view showing the manner according to this invention of sealing off the envelope of a storage tube.
  • a storage tube of known construction is, as shown in the drawing, constituted essentially by a glass envelope 1 enclosing therein an electron gun 2 and a screen or backplate 3 attached to the front inner face of the envelope 1.
  • a storage plate 4 of alkali-halide to which are to be projected electron beams from the electron gun 2 for writing therein a desired optical information.
  • the alkali-halide crystals 4 are carried by a metallic crucible 5 facing the backplate 3 at a certain angle in the envelope 1 which is previously evacuated and hermetically sealed off.
  • the crucible 5 is then heated by means of a high frequency bombarder coil 6 to which is applied a high frequency current of the order of 400 kilocycles so as to melt away the alkali-halide crystals 4 carried by the crucible 5.
  • the alkali-halide crystals thus molten away are evaporated and caused to ad here to the inner face of the backplate 3.
  • a drawback is en countered in this manner of evaporation in the difficulty of controlling the thickness distribution of the alkali-halide layer and in the inability of reasonably determining the angle at which the alkali-halide vapor is directed toward the backplate.
  • F IG. 2 illustrates another known method proposed to eliminate these drawbacks, the method being different from that shown in FIG. 1 simply in that the crucible can be moved from the outside of the envelope.
  • the crucible 5' containing therein alkali-halide crystals 4 is carried by a supporting rod 7 extending outwardly of the envelope within a tubular projection 8 which is integral with the wall of the envelope.
  • a magnetic member 9 At the other end of the supporting rod 7 is provided a magnetic member 9 whereby the rod 7 and accordingly the crucible 5' connected therewith can be moved through the guide piece 10 mounted intermediate the crucible and magnetic member.
  • the crucible 5 thus arranged can be readily positioned centrally of the cross section of the envelope by suitably moving the rod 7 by means of the magnetic member 9 so that the alkali-halide vapor emerging from the crucible 5' is evenly adhered to the inner face of the backplate 3.
  • the heating of the crucible is effected by means of a high frequency bombarder coil 6 similarly to the method of FIG. 1. 1
  • the crucible 5 Upon completion of the formation of the alkali-halide storage plate 4, the crucible 5 is moved out of the envelope 1 into the tubular projection 8 by pulling the magnetic member 9 through manipulation of a suitable magnet (not shown) from outside.
  • a suitable magnet not shown
  • the projection is sealed off on the plane indicated at P and the excess portion of the projection is cut off. The evaporation of the alkali-halide crystals can thus be carried out without leaving the crucible within the envelope in this manner of prior art.
  • the alkali-halide layer 4 is formed on the backplate 3 prior to the mounting of the electron gun 2 in the envelope.
  • the electron gun 2 is then secured to the stern glass 11 by means of a supporting member 12.
  • the stem glass 11 is mounted afterwards fixedly on the envelope 1 through glass processing which is to be conducted subsequent to the stage herein. indicated. With the stern glass 11 still kept disconnected from the envelope 1, as shown, there is formed a clearance 13 inbetween.
  • Designated at 14 is a gas burner for heating the end portion ofthe envelope to thereby seal it off with the stem glass 11.
  • a flow of dried air is introduced into the envelope 1 through a guide 15 and is discharged initially through the clearance 13 between the envelope 1 and stem glass 11 and, once the clearance is sealed off, through the clearance between the stem glass 11 and guide 15.
  • the water vapor resulting from the combustion by the gas burner 14 is substantially kept from the alkali-halide layer 4.
  • FIG. 4 sketchily illustrates a preferred example of the method carrying out the invention
  • the glass envelope 1 is previously split laterally into two halves la and lb with a gap 16 formed at a suitable distance, even as short as 5 cm., from the front end of the envelope 1 so as to facilitate the evaporation of the alkali-halide crystals onto the backplate 3.
  • an envelope with enlarged bulb face it may be cut off at a portion with considerably increased sectional area, making it possible to mount on the front inner face of the envelope a backplate with previously evaporated alkalihalide layer.
  • the cut ends of the halves la and lb are hermetically sealed off by heating the particular portions.
  • the heating of the cut ends of the halves la and 1b may be effected by means of a gas burner 17 at the entire peripheries of the ends.
  • the means for heating the alkali-halide layer 4 for this purpose is constituted essentially by heating element 18, a holder 19 for retaining the heating element to the envelope 1 and transferring the heat to that portion of the envelope which in turn transfers the heat to the alkali-halide layer 4, and a shaft connected at one end with the heating element and at the other with a rotating means (not shown) for constantly rotating the envelope 1 relative to the gas burner 17 in the course of sealing the gap 16.
  • the heating element 18 may preferably be so arranged as to heat the alkalihalide layer 4 at the temperature ranging from 100 C. to 400 C., although at a temperature from 50 C. to 100 C. the results will prove acceptable at an appreciable sacrifice in the performance quality.
  • the alkali-halide layer 4 thus being heated concurrently with the heating of the cut ends of the halves la and lb of the envelope 1, the alkali-halide layer 4 is prohibited from absorbing the moisture to such an extent that the layer becomes so wet as to no longer permit of the creation of an F-center therein. Separation of the envelope 1 into two halves, moreover, will provide for ease and accuracy of forming the alkali-halide layer on the backplate, since the material alkalihalide crystals can be located sufficiently close to the backplate.
  • a process of producing an electron tube having an evaporated alkali-halide layer formed on the inner face of the backplate mounted on the wall of the envelope of said tube comprising dividing said envelope into at least two pieces at suitable portions therein to facilitate evaporation of alkali-halide crystals onto said inner face of the backplate, heating said suitable portions for hermetically sealing the envelope and concurrently heating that portion of the envelope which surrounds said alkali-halide layer.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Luminescent Compositions (AREA)
  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
US830439A 1968-06-07 1969-06-04 Method of sealing an electron tube Expired - Lifetime US3582175A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP43039788A JPS4925394B1 (enrdf_load_stackoverflow) 1968-06-07 1968-06-07

Publications (1)

Publication Number Publication Date
US3582175A true US3582175A (en) 1971-06-01

Family

ID=12562664

Family Applications (1)

Application Number Title Priority Date Filing Date
US830439A Expired - Lifetime US3582175A (en) 1968-06-07 1969-06-04 Method of sealing an electron tube

Country Status (6)

Country Link
US (1) US3582175A (enrdf_load_stackoverflow)
JP (1) JPS4925394B1 (enrdf_load_stackoverflow)
DE (1) DE1928013B2 (enrdf_load_stackoverflow)
FR (1) FR2010378A1 (enrdf_load_stackoverflow)
GB (1) GB1252316A (enrdf_load_stackoverflow)
NL (1) NL6908589A (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020153838A1 (en) * 2001-04-24 2002-10-24 Johnston David W. High pressure lamp bulb and method of induction sealing

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2400062A (en) * 2003-03-29 2004-10-06 Bisk Uk Ltd Tool holder adaptor

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020153838A1 (en) * 2001-04-24 2002-10-24 Johnston David W. High pressure lamp bulb and method of induction sealing
US6641449B2 (en) * 2001-04-24 2003-11-04 Osram Sylvania Inc. High pressure lamp bulb and method of induction sealing

Also Published As

Publication number Publication date
DE1928013A1 (de) 1969-12-11
DE1928013B2 (de) 1972-03-23
FR2010378A1 (enrdf_load_stackoverflow) 1970-02-13
GB1252316A (enrdf_load_stackoverflow) 1971-11-03
NL6908589A (enrdf_load_stackoverflow) 1969-12-09
JPS4925394B1 (enrdf_load_stackoverflow) 1974-06-29

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