Document peDL1k0ZpaJBdwobnZxb8qvQa

United States Patent m Marks [in 4,127,313 [45] Nor. 28,1978 [54] HIGH VOLTAGE ELECTRON TUBE BASE WITH DRIP RELIEF MEANS [75] Inventor: Brace G. Mario, Lancaster, Pa. [73] Assignee: RCA Corporation, New York, N.Y. [21] Appl. No.: 798,125 [22] Filed: May 18,1977 [51] Intel.*........................................... H01R33/76 [52] U.S. CL................................ 339/144 T; 313/318 [58] Field of Search.................. 338/143, 144, 194 R; 313/318, 51, 477, 482 [56] References Cited U.S. PATENT DOCUMENTS 2,192,760 3,916,238 4,040,708 3/1940 Thorson 339/194 R X 10/1975 Suzuki............................... 339/143 T X 8/1977 Neuber et al................... 339/143 T X FOREIGN PATENT DOCUMENTS 780,149 7/1957 United Kingdom ................. 339/143 T Primary Examiner--Roy Lake Assistant Examiner--E. F. Desmond Attorney, Agent, or Firm--E. M. Whitacre; G. H. Bruestle [57] ABSTRACT The base comprises a tubular housing adapted to fit over the exhaust tabulation of an electron tube stem, and a wafer flange extending outwardly from the open end thereof. The flange is apertured to receive an array of conductors of the stem. A recess is provided in the wafer flange facing the stem and a passageway commu nicating therewith is provided through the base sepa rate from the housing cavity for the purpose of injecting a dielectric material into the recess around some of the stem conductors. The passageway may, e.g., be through the flange or in the housing wall. A shoulder is provided on the recessed face ofthe wafer flange to provide relief for random protuberances on the periphery of the stem to permit non-tilted mounting of the base on the stem. 8 Claims, 12 Drawing Figures U.S. Patent Nov. 28,1978 Sheet 1 of 3 4,127,313 *1 U.S. Patent Nov. is, \9is Sheet 2 of 3 4,127,313 U.S. Patent Nov. 28, im sheet 3 of 3 4,127,313 339 4,127,313 1 neck, it causes a drip or slight protuberance in the glass HIGH VOLTAGE ELECTRON TUBE BASE WITH to form at one point around the periphery of the stem. DRIP RELIEF MEANS When prior art bases have been applied to stems having drips of this type, the base is caused to tilt relative to the This invention relates to electron tube bases and par longitudinal axis of the tube. Such tilt, in addition to ticularly to those of the wafer type which include a being aesthetically undesirable, often creates problems body of dielectric material molded therein for the pur in inserting the base into its mating socket. Further pose of increasing the voltage breakdown between the more, the gap between the base and stem due to the lead-in conductors of the base. tilting frequently allows the dielectric material injected BACKGROUND OF THE INVENTION 10 into the base to flow therefrom leaving a deficiency of material to provide the desired dielectric body for high One type of electron gun recently proposed for color voltage breakdown insulation. picture tubes is described in U.S. Pat No. 3,995,194, issued to Blacker et al. This gun includes an electrode to SUMMARY OF THE INVENTION whichan operating voltage ofapproximately 12 kilovolts IS A wafer type electron tube base has an exhaust tabu is applied. In the manufacture of tubes incorporating lation housing and an apertured wafer flange extending such guns, it is often desired to apply a "spot-knocking" outwardly therefrom. The wafer flange is provided voltage of approximately 30 kilovolts to this electrode with drip relief means in the form ofa shoulder or ridge in order to remove sharp points and particles therefrom to permit non-tilted mounting of the base onto a con which might otherwise later cause harmful arcing dur- 20 ventional electron tube stem. ing tube operation. This spot-knocking voltage must be brought in through the base and stem of the tube, and BRIEF DESCRIPTION OF THE DRAWINGS severe voltage breakdown problems are encountered FIG. 1 is a side elevation view with parts broken when conventional prior art bases are used. away of the novel tube base disposed in mating relation U.S. Pat No. 3,278,886 to Blumemberg et al discloses 25 with a cathode ray tube, only the stem and adjacent a type of wafer base in which a housing is disposed over neck portion of which are shown. the exhaust tubulation of an electron tube stem and the FIG. 2 is an enlarged bottom plan view of the tube stem's lead-ins are disposed through apertures in a base of FIG. 1 taken along the line 2--2 thereof. wafer flange extending from the housing. U.S. Pat. No. FIG. 3 is an enlarged top plan view of the electron 3,979,157 to Dimattio discloses a modification of this 30 tube base of FIG. 1 taken along the line 3--3 thereof. type of wafer base in which the lead-ins are disposed in FIGS. 4, 5, 6 and 7 are sections taken through the grooves in the housing wall of the base and lie against tube base of FIGS. 1,2 and 3 along the lines 4--4,5--5, the floor of the grooves. 6--6, and 7--7, respectively of FIG. 2. The Blumemberg et al base is especially designed for FIGS. 8 and 9 are enlarged longitudinal section views high voltage applications. To this end it incorporates a 35 of modifications of the base of FIGS. 1-7. tubular silo structure which surrounds one of the lead- FIGS. 10 and 11 are plan views similar to that of ins to which high voltage is applied, and a recess in the FIG. 3 of modifications of the base of FIGS. 1-7. base into which a dielectric material is molded around FIG. 12 is a perspective view of another embodiment the lead-ins. Both of these features serve to increase of the novel tube base. resistance against high voltage breakdown. 40 In mounting a base of the Blumemberg et al type to an electron tube stem, it has been the practice heretofore to DESCRIPTION OF PREFERRED EMBODIMENTS simply insert a quantity ofplastic dielectric material into Referring to FIGS. 1-7, a glass neck portion 10 of a the recess of the base and then apply the base to the color picture tube is closed at one end with a glass stem stem. Since the dielectric material is applied to the base 45 12 which includes an array of stiff conductors 14. The while it is out of contact with the stem, the result is a conductors 14 are sealed through the stem 12 and ex messy process. Alternatively, the plastic dielectric ma tend therefrom in a circular array parallel to each other. terial may be injected through the exhaust tubulation The stem 12 also includes a closed off exhaust tubula housing. When the latter is done, sufficient material tion 16 disposed centrally within the circular array of must be injected to completely fill the housing in order 50 conductors or leads 14. A base member 18 is attached to that some of the dielectric material is forced into the the end of the stem 12. recess in the bottom of the base. The difficulty with this The base member 18 is of the wafer type and com procedure is that exhaust tubulations are not of uniform prises a cylindrical housing 20 having an opening 21 at volume from tube to tube, and hence the amount of one end and a wafer flange 22 which extends radially dielectric material which must be injected varies from 55 outwardly therefrom. The cylindrical housing 20 is tube to tube. This prevents the injection of a specific hollow and fits loosely over the exhaust tubulation 16. amount of material and thus complicates the injection The outer cylindrical surface of the housing 20 is pro process. vided with a series of longitudinal grooves 24 which Prior art bases such as the Blumemberg et al base extend from the wafer flange 22 to the opposite distal experience another problem when they are used with 60 end of the housing 20. The wafer flange 22 is provided neck-stem structures as conventionally fabricated in the with a circular array of apertures 25 therethrough. The color picture tube industry. In fabricating the neck-stem circular array of conductors 14 are disposed through structure of a picture tube envelope, the neck is heated the array of apertures 25 and lie one in each of the to soften the glass and fuse it to the stem. The heating is grooves 24. continued until a short length of neck section extending 65 The base 18 is also provided with a tubular chamber beyond the stem is completely severed from the remain or silo 26 (FIGS. 2 and 6) disposed coextensively along der of the neck and drops free therefrom. When this side the housing 20. The silo 26 is closed at one end by short piece of neck section separates from the rest of the the wafer flange 22 and is open at the opposite end. The 4.127.313 34 silo 26 receives therein one of the leads 14 which is section 32a where high voltage breakdown insulation is intended to have a high spot-knocking voltage applied more important. thereto. The silo 26 serves to provide a greatly in In the embodiment of the base of FIGS. 1-7, the creased discharge path from the high voltage lead con fill-hole 36 is shown in its simpliest form as a straight tained therein to any one of the adjacent leads. 5 cylindrical bore. However, other forms of the fill-hole, Also provided to increase voltage breakdown be wherein the passageway thereby provided may be bent, tween the leads is a radially extending fin 28 disposed may be provided as alternatives. For example, in FIG. 8 between two adjacent leads 14. The fin 28, while not as a base 118 is provided with a fill-hole 136 which in effective as the silo 26 in preventing high voltage break cludes a first portion 142 communicating with a recess down, is nevertheless adequate for the lesser voltages to 10 132 in the wafer flange portion 122 of the base 118, and be applied to the leads 14 on the opposite sides thereof. a second portion 144 which is offset toward the central The stem-contacting face 30 of die wafer flange 22 is axis of the base 118 and is somewhat enlarged relative to provided with a recess 32. The depth of the recess 32 is the first portion 142. The offset is preferred so that not critical. It need be only deep enough to allow a thin when a dielectric injection nozzel is pressed against the layer of dielectric material molded therein to form a 15 opening in the fill-hole 136, the force applied to the base continuous body that will contact selected ones of the 118 will be more nearly axial and thus less likely to leads 14 at their interface with the glass body of the cause tilting of the base on the stem 12. The enlarge stem 12. Typically, a depth of about 2.S mm has been ment ofthe second portion 144 allows easier injection of found to be satisfactory. The recess 32 has a lateral dimension sufficient to completely encompass the high voltage lead 14 in the silo 26 and the adjacent lead 14 disposed between the silo 26 and the fin 28. The recess 32 is generally defined by a arcuate boundary which passes through the centers of the rest of the leads 14. However, fillet-like cavities 34 provided at each of the other leads 14 allow dielectric material injected into to the dielectric material into the fill-hole 136. In FIG. 9, another embodiment of fill-hole is shown. A base 218 includes a fill-hole 236 comprising a first portion 242 communicating with a recess 232 in the wafer flange portion 222 of the base 218, and a second portion 244 offset therefrom and disposed nearly coaxi ally of the base 218. The second portion 244 is ex tremely enlarged relative to the first portion 242, similar to that provided in the fill-hole 136 shown in FIG. 8. recess 32 to also surround those leads as well where Also shown in FIG. 9 is a piston 250 preferably hav they enter the stem 12. ing a rubber O-ring 252 at one end thereof. The piston In actual practice not all leads will have high voltages 3Q 250 is adapted to be received snuggly within the second applied to them and hence need not be surrounded by portion 244 ofthe fill-hole 236. Thus, a charge ofdielec the dielectric material. To this end, in a preferred prac tric material can be disposed in the second portion 244 tice with the base 18, the dielectric material is forced into the recess 32 until it encompasses the high voltage and then the piston 250 advanced thereinto to force dielectric material into the first portion 242 and into the lead 14 in the silo 26 and the lead 14 between the silo 26 recess 232 of the base 218. and the fin 28, and spreads further across the recess 32 Referring again to FIG. 1, the stem 12 includes a glass until about half of the lateral dimension of the recess is drip 37 at the periphery of the stem 12 which extends a filled. short distance beyond the otherwise even periphery of In order to access the recess 32 for the purpose of the stem. The drip results from the conventional proce injecting plastic dielectric material thereinto, a passage- 40 dure employed in fabricating neck-stem structures as way or fill-hole 36 (FIGS. 2, 3, and 7) is provided in the described hereinabove. The novel base 18 is provided base 18, preferably in a wall of the housing 20, and with drip relief means which allows the base to be extends from the distal end thereof to the opposite end seated axially aligned with its tube. This means is pro ofthe base 18 where it communicates with the recess 32. vided in the form of an annular shoulder 38. The shoul Dielectric material can be dispensed through the fill- 45 der 38 allows the drip 37 to be received radially out hole 36 simply by positioning a dispenser nozzle at the wardly from the shoulder into a recessed portion of the distal end thereof. Since the fill-hole 36 has a uniform wafer flange 22. volume from base to base, a specific metered amount of The drip relief means may be thought ofsimply as the dielectric material can be dispensed thereinto such that removal of. ah annular peripheral portion of the wafer it will fill the fill-hole 36 and enter the recess 32 with a so flange 22 to produce the shoulder 38, or as an annular slight overflow into the housing 20 around the exhaust tubulation 16. Thus, regardless of the volume of the ridge disposed on the end surface of the wafer flange 22 having the shoulder 38 as one side surface thereof. Ex exhaust tubulation 16, the recess 32 can be filled without fear of overflow out of the base 18 thereby causing perience has shown that in conventional procedures used to seal a stem 12 to the neck section of a picture messy spillage. 55 tube, the largest drips 37 which are normally produced In order to insure a complete filling of that portion of can be relieved by a shoulder 38 which is approximately the recess 32 in the region of the silo lead 14, the recess 0.75 mm high. is divided into two sections. A first section 32a is arcu To better insure that the dielectric material thor ate in shape and encompasses th fill-hole 36, the silo lead oughly surrounds the silo lead 14, a portion of the drip 14, and the adjacent lead 14 between the silo 26 and fin 60 relief ridge 38 can be either cut away adjacent to the silo 28. A second section 326 is constituted by the remainder lead 14, or it can be displaced away from the lead. of the recess 32. The first section 32a is partially sepa FIG. 10 illustrates a base 318 which differs from the rated from the second section 326 by a lip 35 (FIGS. 3, base 18 in that it has a discontinuous drip reliefridge 338 4, 6 and 7). Thus, when dielectric material is injected with a portion thereofcut away adjacent to the silo lead into the recess 32 from the fill-hole 36, it enters the first 65 314. This produces a gap 339 which allows the dielec section 32a and substantially fills it before it spills over tric material to better flow around the silo lead 314. the lip 35 into the second section 326. This insures a Alternatively, the ridge may be made discontinuous thorough encompassing of the two leads 14 in the first in a number of places so that it contacts the stem 12 with 4,127,313 56 a plurality of short sections, which function somewhat 1. A base member adapted to be disposed over a in the nature ofa plurality of feet on the base which abut circular array of lead conductors and an exhaust tabula the stem 12. The preferred embodiment of the ridge tion of an electron tube stem having a peripheral glass shoulder is that it be as fully continuous as possible and protuberance, said base member comprising: still allow adequate insulation around the high voltage 5 a. a tubular housing having an open end for receiving lead. When the ridge shoulder is completely continu said exhaust tabulation therein, ous, it serves the additional function of providing a dam b. a flange having a diameter at least as large as the or seal wall for the plastic dielectric material which is diameter of said stem extending outwardly from injected into the recess. This allows the production of a said housing at said open end thereof, neater, cleaner product 10 c. an array of apertures through said flange for re FIG. 11 illustrates a base 418 which differs from the ceiving said array oflead conductors therethrough, base 18 in that it has a drip relief ridge 438 which in and cludes a sharp arcuate section 441 adjacent to the silo d. drip relief means comprising a part of said flange lead 414. The arcuate section 441 is displaced away including a stem-contacting surface which is out from the silo lead 414 more than the drip relief ridge 38 15 wardly of said circular array and inwardly of the of the base 18 so that the dielectric material can better periphery of said flange and of said peripheral pro flow around the silo lead 414. tuberance to allow non-tilted mounting of said base FIG. 12 illustrates a base 518 useful in applications on said stem. with less severe high voltage breakdown problems. The base 518 is of the wafer type with a tribulation housing 2. The base member of claim 1 wherein said drip relief means comprises an annular receding shoulder on 520 and a wafer flange 522 at the open end of the hous ing. An array of leads 514 from a stem structure 512 are received through an array of apertures in the wafer flange 522, and are free standing. The flange 522 is provided with a recess 532 in the face thereof adapted to abut the stem 512. At least one of the leads 514 passes 2J said flange which is inwardly of the periphery of said flange, outwardly of said array of apertures and in wardly of said peripheral protuberance. 3. The base member of claim 1 wherein said drip relief means comprises an annular ridge on said flange inwardly of the periphery of said flange. 4. The base member of claim 3 wherein said annular through the wafer flange 522 within the recess 532. A ridge has a gap therein adjacent one of said lead-in dielectric fill-hole 536 is provided through the wafer conductors. flange 522 and opens into the recess 532 for injecting 5. The base member of claim 3 wherein said ridge is dielectric material into the recess around the leads discontinuous and in the form of a plurality of feet cir therein. Optionally, one or more fins 528 may be pro cumferentially spaced from each other. vided along the housing 520 between adjacent leads 514 to improve high voltage breakdown. 6. The base member of claim 3 wherein said annular ridge has a sharp arcuate section opposite and displaced As shown in FIGS. 2, 3 and 5, a blind bore 40 is 35 away from one of said apertures. provided in the housing 20 at one of the lead locations 7. A base member adapted to be disposed over an such that a lead 14 from the stem 12 can be received array of lead conductors and an exhaust tabulation of an therein. No external contact is accessible to this lead electron tube stem, said base member comprising: from the base 18. The purpose of this structure is to a. a tubular housing having an open end for receiving permit use of a universal type stem 12 having a fixed 40 said exhaust tabulation therein, number of leads 14 even though some of them will not b. a flange extending outwardly from said housing at actually be used to make contact with any electrodes said open end thereof, inside the picture tube itself. Whereas only one such c. an array of apertures through said flange for re bore 40 is shown in the drawings, additional blind bores ceiving said array of conductors therethrough, may be provided at other lead locations. 45 A lead 14 may also be disposed in the fill-hole 36. To this end, the fill-hole 36 is located at one of the regular d. a recess in said flange encompassing said open end and at least one of said apertures into which dielec tric material can be molded, and lead locations in the circular arrays of leads 14. Materials suitable for use as the dielectric are those which can be injected in liquid form and then hardened 50 e. a dam substantially surrounding said recess and adapted to contact said stem and thereby provide an enclosure into which said dielectric material can to produce a good dielectric insulator body. The sili be injected and contained. cone rubbers are useful in this respect but suffer from 8. The base member of claim 7 which is adapted to be the disadvantage of requiring a rather lengthy curing disposed on a stem having an exhaust tabulation, a cir time which causes a slow down on the production line. cular array of lead conductors surrounding said exhaust Preferred materials are the hot melt polyamide resins 55 tabulation, and a peripheral glass drip protuberance which are thermoplastic. One such resin found to have outwardly of said array; and wherein acceptable dielectric properties is that sold by General said flange has a diameter at least as large as the diam Mills under the trade name Versalon 1138. eter of said stem, and Materials suitable for the base itself are hard strong said dam comprises an annular ridge on said flange ones which have good dielectric properties and can be 60 disposed outwardly of said array and inwardly of easily molded to the desired shape. Such materials in the periphery of said flange and of said glass drip clude glass filled plastic resins. A preferred material is protuberance, to thereby constitute a drip relief one sold under the trade name of Celanex 3310 by Cel- means to allow non-tilted mounting of said base on anese Plastics Company. What is claimed is: 65 said stem. * * * * *