US3242253A

US3242253A - Electron discharge devices

Info

Publication number: US3242253A
Application number: US299578A
Authority: US
Inventors: James S Bailey; Henry H Schmalz
Original assignee: Rauland Borg Corp
Current assignee: Rauland Borg Corp
Priority date: 1963-08-02
Filing date: 1963-08-02
Publication date: 1966-03-22
Anticipated expiration: 1983-03-22

Description

March 22, 1966 J. 5. BAILEY ETAL 3,242,253

ELECTRON DISCHARGE DEVICES Filed Aug. 2, 1963 -28 INVENTORS 1701 e fi z'Ze 25 211 2215 c zna E3} 97 w y- United States Patent 3,242,253 ELECTRON DISCHARGE DEVICES James S. Bailey, Chicago, and Henry H Schmalz, Deerfield, Ill., assignors to The Rauland Corporation, Chicago, III., a corporation of Illinois Filed Aug. 2, 1963, Ser. No. 299,578 3 Claims. (Cl. 174-5058) This invention relates to electron discharge devices of the type having evacuated sealed containers such as cathode ray tube-s, and more particularly toa stem for such devices.

Electron devices such as television display tubes usually have an envelope consisting of a funnel with a fluoroescent on its face and a narrow neck portion which contains an electron gun structure. A stem is used for sealing the end of the neck in order that the envelope may be evacuated and in addition includes lead-in wires which are coupled to the electron gun.

Such a stem includes a disc-like press of glass which is hermetically sealed at its edge to the end of the neck of the envelope. The press has a central opening which is afiixed to an exhaust tube, and lead-in wires are embedded in the press around the exhaust tube and its central opening. The electron gun assembly is then supported inside the envelope by the lead-in wires extending through the press.

In a system of this type is is a major problem to eliminate leakage paths which occur along the lead-in wires allowing air to enter the evacuated tube, thereby destroying the tubes effectiveness. Normally in the past, a glass pipe has been placed around each lead-in wire as it enters and leaves the press in order to effectively lengthen the portion of the lead-in wire which is sealed to the press. This preventive measure, however, has the disadvantage .that during the manufacturing process, movement of the lead-in wire may occur and cause a p'ip to break or chip, which in turn produces an air leakage path; depending on the configuration of the pip, a reverse curve is usually present which makes it more susceptible to breakage, since stress concentrations may tend to build up at these points.

If the press is made thicker to provide a longer leakage path, heat transfer problems with the attendant build up of stress concentrations, arise in conjunction with the making of the press itself. In addition, ideally the edge of the press should be of approximately the same thickness as the tube neck to obtain a good seal between the two.

It is, therefore, a major object of this invention to provide an improved stem for an electron discharge device.

It is another object of this invention to provide a stem which obviates the above defects.

It is still another object .to provide a stern which eliminates air leakage path-s.

It is yet another object to provide a stem in which the build up of stress concentration is prevented.

In accordance with the invention, a cathode ray tube having an envelope with an elongated neck portion comprises a disc-like glass press hermetically sealed at its edge to the neck portion of the envelope of the cathode ray tube. The press has a central exhaust opening which is sealed to, and communicates with, an exhaust tube, and the press is also constructed to have a rim portion of a predetermined uniform thickness extending inwardly (from its outer edge while an integral thicker annular por- 3 ,242,253 Patented Mar. 22, 1966 tion extends inwardly from the rim portion to the exhaust tube, the surfaces of the rim portion and the thicker portion on the side of the press facing the exhaust tube being flat and parallel one to the other. Metal lead-in wires extend through the thicker annular portion of the press in spaced relation about the central exhaust opening and are hermetically sealed to the press. The press is further provided with individual substantially conicall-ly tapered recesses around the lead-in wires with the glass of the press flaring gradually outwardly from recessed contact with the lead-in wires, and the lead-in wires are spaced from the glass, and thus free to flex, within the recesses.

The features of the present invention, which are believed to be novel are set forth with particularity in the appended claims. The organization and manner of operation of the invention, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawing in the several figures of which like reference numerals identify like elements, and in which:

FIGURE 1 is a fragmentary perspective view partly cut away, of an electron device embodying the present invention;

FIGURE 2 is an enlarged sideview, partly in crosssection, of a portion of the device of FIGURE 1; and

FIGURE 3 is a partial cross-sectional view of a fixture used in sealing in a stem embodying the present invention.

In FIGURE 1 a television display tube has an envelope 10 which comprises a funnel 11 with a phosphor coated faceplate (not shown) and a neck portion 12. A stem 14 is sealed to the envelope at the end or terminal portion of neck 12 and has mounted on it an electron gun structure 15. A conventional pin base 13 is cemented to the end of neck 12.

Referring now to both FIGURE 1 and FIGURE 2, which shows a detailed View of stem 14, the stem includes a disc-like press 17 which may be constructed of glass, for example, sealed at its edge 18 to the end or terminal portion of neck 12. As illustrated, the thickness of the press at its edge substantially matches the thickness of neck 12. The press includes a central exhaust opening 19 which communicates with an exhaust tube 2'0 sealed to the press. This exhaust tube is utilized only during the construction of the electron device and is sealed off after exhaust as shown, in a manner well known in the art. Lead-in wires 22 are hermetically sealed into press 17 and spaced around opening 19. Around each lead-in wire is placed a glass pip 23 on the inside of the press facing the gun structure to increase the length of the seal between the glass and lead-in wires and to increase the internal electrical leakage paths. Pips 23 are an integral portion of press 17 and are formed concurrently with the press structure.

In accordance with the invention, an annular-portion 24 encompasses lead-in wires 22 and is relatively thicker than the portion of press 17 contacting neck 13. For example, in a stem for achieving the advantage of the invention in television picture tubes, edge 18 of the press may be .080 inch thick while annular portion 24 may be approximately .105 inch thick. The surface 25 of annular portion 24 which is on the same side of press 17 as exhaust tube 20, has a substantially planar configuration as illustrated; that is, the surface is substantially level and flat. More specifically, thicker annular portion 24 includes an abrupt step 26 which is utilized as the transition between thin outer portion and the thick inner portion 24 of press 17. Wholly re-entrant seals 27, as distinguished from the provision of pips in prior constructions, are provided around each lead 22 for greater resistance to chipping if the lead is bent. Step 26 may be modified to provide a smoother transition between the thick and thin portion of the press without losing many of the novel advantages of the invention, but an abrupt step is useful in one aspect to be described below.

Thicker inner portion 24, provides a seal for lead-in wires 22 which is more effective than prior art seals for several reasons. First, the elimination of a pip on the exterior surface 25 eliminates any possibility of cracking the entire pip due to the relatively vigorous flexing of the leads which may take place during the construction of the tube. However, the length of the glass seal is still sufficiently long, to prevent air leakage paths due to the step type construction. The build up of stress concentrations on or near the surface 25 is prevented, since its substantially planar configuration eliminates reverse angle curves which are inherent in the previously employed pip type constructions. Lastly the matching of press 17 to the relatively thin tube neck is facilitated as a result of the novel construction.

As mentioned above, annular portion 24 may be formed by using either an abrupt step 25 or a relatively smooth transition. However, the abrupt step is advantageous in locating the system in relation to the tube envelope during mating of the two. In FIGURE 3, stem 14 is retained in a cylindrical jig 28 having a flared out end portion 29 which is adapted for mating with step 26. The flared end portion 29 accurately locates stem 14 on fixture 28. Tube envelope is placed in second jig (not shown) which is aligned with jig 28 with tube neck 12 slipping over stem 14. Thus, stem 14 is accurately lo cated by means of jig 28 and step 26 in relation to tube envelope 10. Both the stem and tube are rotated together at the same speed, subjected to a flame 30, and sea-led in a manner well known in the art to form a completed cathode ray tube.

The invention as described provides an improved stem which by its novel construction eliminates any possib-ilty of the creation of air leakage paths and furthermore accurately locates the stem on the tube.

While a particular embodiment of the present invention has been shown and described, it is apparent that various changes and modifications may be made, and it it there-fore intended in the following claims to cover all such modifications and changes as may fall within the true spirit and scope of this invention.

We claim:

1. A cathode ray tube having an envelope with an elongated cylindrical neck comprising:

a disc-shaped glass press hermetically sealed about its outer edge to the outer end of said neck;

means defining an exhaust opening extending through the central portion of said press;

an externally protruding exhaust tube sealed to said press and communicating with said exhaust openmg;

said press having a rim portion of a predetermined uniform thickness extending inwardly from said outer edge and further having an integral thicker ex :ternally stepped annular portion extending inwardly from said rim portion to said exhaust tube, the surfaces of said rim portion and said thicker portion on the side of said press facing said exhaust tube being flat and parallel one to the other;

flexible metal lead-in wires extending through and hermetically sealed to said thicker annular portion of said press with said wires being circumferentially spaced around said exhaust opening;

and means defining individual substantially conically i tapered open recesses in said press around said leadin wires with the walls of said recesses flaring gradually outwardly from recessed contact with said leadin Wires, said lead-in wires being spaced from said glass, and free to flex, within said recesses.

2. A cathode ray tube having an envelope with an elongated cylindrical neck comprising:

means defining a central exhaust opening in said press;

an externally protruding exhaust tube sealed to said press and communicating with said exhaust opensaid press having a rim portion of a predetermined uniform thickness extending inwardly from said outer edge and further having a thicker externally stepped annular portion extending inwardly from said rim portion to said exhaust tube, the surfaces of said rim portion and said thicker portion on the side of said press facing said exhaust tube being flat and parallel one to the other;

flexible metal lead-in wire-s of uniform diameter extending through and hermetically sealed tosaid thicker annular portion of said press with said wires lbeing circumferentially spaced around said exhaust opening;

and means defining individual substantially conic-ally tapered open recess about said lead-in wires in both the internal and external surfaces of said press with the walls of said recesses flaring gradually outwardly from recessed contact with said lead in wires, said lead-in wires being spaced from said glass, and free to flex, within said recesses.

3. A cathode ray tube having an envelope with an elongated cylindrical neck portion, in which is mounted an electron gun and which is of a predetermined interior diameter throughout its length except for an annular necked-down region at its outer end and located a predetermined distance from said funnel portion with said necked down region being formed incident to mounting said gun within said neck portion, comprising:

a disc-shaped glass press having a predetermined outer diameter less than said predetermined interior diameter and hermetically sealed around its outer edge to said necked-down region;

means defining a central exhaust opening in said press;

an externally protruding exhaust tube sealed to said press and communicating with said exhaust opening;

flexible metal lead-in wires extending through and hermetically sealed to said press with said wires being circumferentially spaced around said exhaust opening;

said press having a rim portion of a predetermined uniform thickness extending inwardly from said outer edge to the vicinity of said lead-in wire-s and further having an integral thicker externally stepped annular portion extending inwardly from said rim portion to said exhaust tube, said thicker portion encompassing said lead-in wires, and the surfaces of said rim portion and said thicker portion on the side of said press facing said exhaust tube being flat and parallel one to the other, the transition region between said rim portion and said thicker portion being circular-1y concentric with the axis of the press and defining a reference surface accurately spaced a preselected constant distance from said funnel in correspondence with said predetermined distance and with said reference surface during assembly presenting an indexing abutment enabling orientation of said press concentrically within said neck portion and at the position at which said necked-down region is formed;

and means defining individual substantially conically tapered open recess about said lead-in wires in both the internal and external surfaces of said press with the Walls of said recesses flaning gradually outwardly from recessed contact with said lead-in Wires, said lead-in wires being spaced from said glass, and free rto flex, within said recesses.

References Cited by the Examiner UNITED STATES PATENTS 2,082,848 6/1937 Rose 220-2 X 2,174,375 9/1939 Be-ggs 1745O X 2,205,502 6/1940 Tromp 17450 X 2,235,135 3/1941 Andresen 17417 2,250,18 7/1941 Miller 174-50 X 6 2,497,545 2/ 1950 Greiner 174-50 X 2,568,460 9/ 1951 NoLte 220-2 X 2,904,456 9/ 1959 Nolte.

FOREIGN PATENTS 7 1,845 1/ 1941 Czechoslovakia. 964,806 2/1950 France.

ROBERT K. SCHAEFER, Primary Examiner.

0 DARRELL L. CLAY, JOHN F. BURNS,

W. B. FREDERICK, Examiners.

Claims

1. A CATHODE RAY TUBE HAVING AN ENVELOPE WITH AN ELONGATED CYLINDRICAL NECK COMPRISING: A DISC-SHAPED GLASS PRESS HERMETICALLY SEALED ABOUT ITS OUTER EDGES TO THE OUTER END OF SAID NECK; MEANS DEFINING AN EXHAUST OPENING EXTENDING THROUGH THE CENTRAL PORTION OF SAID PRESS; AN EXTERNALLY PROTRUDING EXHAUST TUBE SEALED TO SAID PRESS AND COMMUNICATING WITH SAID EXHAUST OPENING; SAID PRESS HAVING A RIM PORTION OF A PREDETERMINED UNIFORM THICKNESS EXTENDING INWARDLY FROM SAID OUTER EDGE AND FURTHER HAVING AN INTEGRAL THICKER EXTERNALLY STEPPED ANNULAR PORTION EXTENDING INWARDLY FROM SAID RIM PORTIONS TO SAID EXHAUST TUBE, THE SURFACES OF SAID RIM PORTION AND SAID THICKER PORTION ON THE SIDE OF SAID PRESS FACING SAID EXHAUST TUBE BEING FLAT AND PARALLEL ONE TO THE OTHER; FLEXIBLE METAL LEAD-IN WIRES EXTENDING THROUGH AND HERMETICALLY SEALED TO SAID THICKER ANNULAR PORTION OF SAID PRESS WITH SAID WIRES BEING CIRCUMFERENTIALLY SPACED AROUND SAID EXHAUST OPENING; AND MEANS DEFINING INDIVIDUAL SUBSTANTIALLY CONICALLY TAPERED OPEN RECESSES IN SAID PRESS AROUND SAID LEADIN WIRES WITH THE WALLS OF SAID RECESSES FLARING GRADUALLY OUTWARDLY FROM RECESSED CONTACT WITH SAID LEADIN WIRES, SAID LEAD-IN WIRES BEING SPACED FROM SAID GLASS, AND FREE TO FLEX, WITHIN SAID RECESSES.