US3923189A - Quartz to glass seal - Google Patents
Quartz to glass seal Download PDFInfo
- Publication number
- US3923189A US3923189A US378516A US37851673A US3923189A US 3923189 A US3923189 A US 3923189A US 378516 A US378516 A US 378516A US 37851673 A US37851673 A US 37851673A US 3923189 A US3923189 A US 3923189A
- Authority
- US
- United States
- Prior art keywords
- quartz
- envelope
- stem
- glass
- stress relieving
- 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
Links
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Classifications
-
- 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
- H01J5/26—Vacuum-tight joints between parts of vessel between insulating and conductive parts of vessel
-
- 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
- H01J2893/0041—Direct connection between insulating and metal elements, in particular via glass material
- H01J2893/0043—Glass-to-metal or quartz-to-metal, e.g. by soldering
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T403/00—Joints and connections
- Y10T403/21—Utilizing thermal characteristic, e.g., expansion or contraction, etc.
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T403/00—Joints and connections
- Y10T403/21—Utilizing thermal characteristic, e.g., expansion or contraction, etc.
- Y10T403/213—Interposed material of intermediate coefficient of expansion
Definitions
- the seal includes an intermediate annular metallic stress relieving ring dis- 1 U S Cl 220/2 3 313/220 313/721 posed between the quartz envelope and the glass stem.
- the annular metallic stress relieving ring has: a radial 403/28; 403/29 HOlj 17/18; HOlj 61/36 flange portion, plated with a noble metal and sealed to [5 l] Int.
- ver chloride cement a supporting thin narrow relieving portion connected and extending substantially perpendicular to the radial flange portion; and a stem sealing portion which is sealed to the glass stem by conventional sealing techniques and which is interconnected with the annular stress relieving portion.
- the present invention relates to quartz to glass seals and more particularly to strong hermetic seals-between quartz envelopes and glass stems in electron discharge devices.
- the novel quartz-to-glass seal for sealing a quartz envelope to a glass stem in an electron tube, wherein a thin annular metallic stress relieving ring is intermediately disposed between the quartz envelope and the glass stem.
- the ring includes a radial flange portion, which is sealed to the open end of the quartz envelope by a suitable cement.
- a supporting thin narrow annular stress relieving portion on the ring is connected and extends substantially perpendicular to the radial flange portion.
- the ring also includes a stem sealing portion which is sealed to the glass stem by conventional sealing methods.
- FIG. 1 is a cutaway view of a photomultiplier tube.
- FIG. 2 is a cross-sectional view of the tube of FIG. 1 taken along line 2-2.
- FIG. 3 is an exaggerated cutaway view of the quartzto-glass seal of the tube of FIG. 1 in accordance with the invention.
- FIG. 4 is a cross-sectional view of the quartz-to-glass seal in accordance with the invention taken along line 44 of the tube shown in FIG. 1.
- FIGS. 1 and 2 DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1 and 2,-ther c is shown a circular cage photomultiplier tube 10 in which light is focused, from source S. through a side of quartz envelope 1-2 and electron permeable grid 13 onto a photocathode surface 14 for generating electrons.
- electrons emitted from photocathode surface 14 are repeatedly accelerated and multiplied by secondary electron ernissive surfaces 16, in a conventional manner, and ultimately collected as a signal current at anode 18.
- the electrodes of the tube 10 are connected to external potentials by means of leadin pins 20 which are hermetically sealed in a glass stem 22.
- the glass stem 22 In the assembly of the tube 10, prior to activation of the photocathode surface 14, the glass stem 22 must be hermetically sealed to the quartz envelope 12.
- the invention, disclosed herein, is directed to an improved seal between stem 22 and quartz envelope 12.
- the glass stem 22 is disc-shaped and includes an exhaust tubulation 24, approximately centrally located, and an outer peripheral sealing surface 26.
- the glass stem 22 is sealed indirectly tothe quartz envelope 12 through an intermediate stress relieving ring 28.
- the stress relieving ring 28 comprises three portions: an annular stem sealing portion' 30 which is sealed to stem sealing surface 26, a radial flange portion 32 which is sealed to the quartz envelope l2 and an intermediateannular metallic stress relieving portion 34 which comprises an intermediate zone of yieldablesupporting metal.
- the peripheral stem sealingsurface 26 is sealed to the annular stem sealing portion 30 by conventional sealing techniques such as, for example, RF sealing or flame sealing methods.
- the glass stem 22 may be molded into sealing relationship with the annular stem sealing portion 30.
- the shape of the stem sealing portion 30- may vary with the type of seal utilized and is not considered critical;
- the stem 22 consists of a suitable glass, preferably a borosilicate glass, having substantially the same coefficient of thermal expansion as the stress relieving ring 30.
- the material of the stem22 and the stress relievingring 30 are considered to possess substantially'the same coefficient of thermal expansionwhenever the differences in thermally caused dimensional changes in-the two opposing materials is insufflcient to cause cracking of the vacuum seal.
- the seal provided between the annular stem sealing portion 30 of the stress relieving ring 28 and the peripheral stern sealing surface 26 must be vacuum tight and of sufficient strength to withstand external forces normally exerted in the stem region of the tube.
- the stress relieving ring 28 preferably consists of a single thickness of thinKovar (an alloy of cobalt, nickel and iron) material, but may consist of other materials of varying thicknesses having equivalent ductile properties such as: molybdenum, tungsten, or other alloys of nickel, cobalt and iron.
- stress relieving ring 28 is subject to several constraints.
- the thickness of material selected is critical, particularly with regard to intermediate metallic stress relieving portion 34.
- the thickness of the material must not be such as to make the stress relieving portion 34 exceedingly rigid.
- the material must be sufficiently yieldable and flexible to withstand stresses arising from thermally caused dimension changes of the quartz envelope l2 and the stress relieving ring 28 relative to each other.
- Variables which must be considered when selecting the appropriate thickness of the metallic material for the stress relieving portion 34 include, for example, the diameter and thickness of the quartz envelope. ln contrast, however, the stress relieving portion 34 must also be of sufficient strength and rigidity to withstand atmospheric pressure as well as other normal external forces which may be exerted on the stem region of the tube.
- the requisite degree of strength and rigidity is obtained by providing an intermediate stress relieving portion 34 which is relatively narrow in width "W along the longitudinal length of the tube (measured in the direction of axis AA depicted in FIG. 1) as depicted in FIG. 3, exclusive of the stem sealing portion 30. Additional strength is obtained along longitudinal length of the tube by making the stress relieving portion 34 a supporting member which effectively extends the walls of the quartz envelope 12 to the peripheral stem sealing portion 30.
- the chart given below indicates, approximately, the various preferable thickness (T) and longitudinal widths (W) for a Kovar stress relieving portion 34 for various diameter quartz envelopes (D) and various conventional thicknesses of quartz envelopes (Q).
- a radial flange portion 30 which extends in a radial direction relative to the axis A-A depicted in FIG. 1, and which is substantially perpendicular to the intermediate stress relieving portion 34, is sealed to the annular surface 36 of the open end of the quartz envelope 12.
- a sealing surface 38 on the radial flange portion 30 is cleaned and plated with a noble metal material such as, for example, silver, to prevent decomposition, by the base metals in the sealing surface 38, ofa silver chloride cement 40 which is utilized to accomplish the seal with surface 36 of envelope 12.
- a noble metal material such as, for example, silver
- the annular surface 36 of the open end of the envelope [2 is plated with a noble metal, such as, for example, silver.
- Silver chloride is then applied to the surface 36 of envelope 12 by dipping that surface into molten silver chloride.
- the seal between the quartz envelope 12 and radial flange portion 32 is 4 accomplished by placing the two parts together and heating to the melting point of silver chloride (456C. then cooled.
- the seal described above has been found particularly useful for tubes of 0.5 inch to 2.0 inches in diameter. Also, it has been found that a strong simple inexpensive hermetic seal is accomplished whereby differences in the thermally caused dimensional changes between the quartz envelope and its associated annular stress relieving ring, over a temperature range of 400C. to 0C. are yieldable resisted without cracking of the seal. A seal is accomplished which will not collapse under atmospheric pressure, temperature variations between 400C. and 0C., and/or normal external forces which are exerted in the stem region of the tube. Also, assembly of devices with the novel seal does not produce gases which tend to contaminate active elements internal of the assembled devices, such as for example, photocathodes.
- the seal between the quartz envelope 12'and the stress relieving ring 28 numerous variations of that seal may be accomplished by omitting changing or adding other materials which accomplish similar overall functions.
- a cement other than silver chloride might be utilized without deviating from the inventive concept.
- the cement, while preferably silver chloride may comprise other suitable adhesives having comparable characteristics such as, for example, the yieldability and pliability, which are required to provide a flexible and yielding vacuum seal between the opposing quartz and metallic material.
- a quartz-to-glass seal for sealing an annular open end portion of tubular quartz envelope to a glass stem in an electron tube wherein the annular open end of the envelope has an approximate outside diameter within the range of 0.5 to 2.0 inches; and wherein the seal includes an intermediate metallic stress relieving ring, between the annular open end portion of the envelope and the glass stem, of a material selected from the group consisting of: molybdenum, tungsten, and alloys of cobalt, iron, and nickle, and having:
- a supporting thin narrow tubular stress relieving portion having an approximate longitudinal width within the range of from 0.183 to 0.25 inches, an approximate thickness of between 5 and 15 mils; said relieving portion extending substantially perpendicular from said radial flange portion as a tubular extension of said envelope, and
- said yieldable cement comprising silver chloride.
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- Joining Of Glass To Other Materials (AREA)
Abstract
Description
Claims (3)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US378516A US3923189A (en) | 1973-07-12 | 1973-07-12 | Quartz to glass seal |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US378516A US3923189A (en) | 1973-07-12 | 1973-07-12 | Quartz to glass seal |
Publications (1)
Publication Number | Publication Date |
---|---|
US3923189A true US3923189A (en) | 1975-12-02 |
Family
ID=23493419
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US378516A Expired - Lifetime US3923189A (en) | 1973-07-12 | 1973-07-12 | Quartz to glass seal |
Country Status (1)
Country | Link |
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US (1) | US3923189A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4354717A (en) * | 1977-03-28 | 1982-10-19 | Heimann Gmbh | Process for the production of gas discharge lamps |
US4367433A (en) * | 1980-08-25 | 1983-01-04 | Edison International, Inc. | Self ballasted lamp for automotive, aircraft runway, etc. lighting |
EP0384407A1 (en) * | 1989-02-21 | 1990-08-29 | Hamamatsu Photonics K.K. | Discharge tube |
US5899350A (en) * | 1997-01-29 | 1999-05-04 | Futaba Denshi Kogyo K.K. | Hermetic container and a supporting member for the same |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2915153A (en) * | 1956-02-29 | 1959-12-01 | William J Hitchcock | Salt crystal-to-glass seal |
US3281174A (en) * | 1959-02-18 | 1966-10-25 | Varian Associates | Art of sealing quartz to metal |
-
1973
- 1973-07-12 US US378516A patent/US3923189A/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2915153A (en) * | 1956-02-29 | 1959-12-01 | William J Hitchcock | Salt crystal-to-glass seal |
US3281174A (en) * | 1959-02-18 | 1966-10-25 | Varian Associates | Art of sealing quartz to metal |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4354717A (en) * | 1977-03-28 | 1982-10-19 | Heimann Gmbh | Process for the production of gas discharge lamps |
US4367433A (en) * | 1980-08-25 | 1983-01-04 | Edison International, Inc. | Self ballasted lamp for automotive, aircraft runway, etc. lighting |
EP0384407A1 (en) * | 1989-02-21 | 1990-08-29 | Hamamatsu Photonics K.K. | Discharge tube |
US5057742A (en) * | 1989-02-21 | 1991-10-15 | Hamamatsu Photonics K.K. | Discharge tube |
US5899350A (en) * | 1997-01-29 | 1999-05-04 | Futaba Denshi Kogyo K.K. | Hermetic container and a supporting member for the same |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: NPD SUBSIDIARY INC., 38 Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:RCA CORPORATION;REEL/FRAME:004815/0001 Effective date: 19870625 |
|
AS | Assignment |
Owner name: BANCBOSTON FINANCIAL COMPANY Free format text: SECURITY INTEREST;ASSIGNOR:BURLE INDUSTRIES, INC., A CORP. OF PA;REEL/FRAME:004940/0952 Effective date: 19870714 Owner name: BURLE INDUSTRIES, INC. Free format text: MERGER;ASSIGNOR:NPD SUBSIDIARY, INC., 38;REEL/FRAME:004940/0936 Effective date: 19870714 Owner name: BURLE TECHNOLOGIES, INC., A CORP. OF DE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:BURLE INDUSTRIES, INC., A CORP. OF PA;REEL/FRAME:004940/0962 Effective date: 19870728 |
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AS | Assignment |
Owner name: BANCBOSTON FINANCIAL COMPANY, A MA BUSINESS TRUST Free format text: SECURITY INTEREST;ASSIGNOR:BURLE TECHNOLOGIES, INC., A DE CORPORATION;REEL/FRAME:005707/0021 Effective date: 19901211 |
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AS | Assignment |
Owner name: BARCLAYS BUSINESS CREDIT, INC., NORTH CAROLINA Free format text: SECURITY INTEREST;ASSIGNOR:BURLE TECHNOLOGIES, INC.;REEL/FRAME:006419/0542 Effective date: 19921223 |