Document rpEJgQmQrBn72x26m8zEmjMN0

United States Patent [j Marks et al. [ii] Patent Number: 4,633,132 [45] Date of Patent: Dec. 30,1986 [54] SELF-ADHERING CATHODE RAY TUBE BASE [75] Inventors: Gary T. Marks, Phelps; Charles H. Rehkopf; Fred L. Sorensen, both of Seneca Falls, all of N.Y. [73] Assignee: North American Philips Consumer Electronics Corp., New York, N.Y. [21] Appl. No.: 672,519 [22] Filed: Not. 19,1984 [51] IntCl/........................HOIJ 5/54; H01R 33/76 [52] U.S. Q................................. 313/477 R; 313/318; 339/144 T [58] Field of Search.......................... 313/477 R, 318; 174/50.51, 50.59, 50.6; 339/14 T, 64 M, 66 T, 75 T, 94 M, 95 T, 144 T, 145 T, 186 T, 182 T [56] References Cited U.S. PATENT DOCUMENTS 4,040,707 8/1977 Pisano.............................. 313/318 X 4,126,371 11/1978 Puhak........-.................... 313/318 X Primary Examiner--David K. Moore Assistant Examiner--K. Wieder Attorney, Agent, or Firm--John C. Fox [57] ABSTRACT A self-adhering base for a cathode ray tube has a circu lar array of connector pin apertures, three of which are sized to create a force fit with their associated pins. A first high voltage pin aperture is sized smaller than its associated pin, and the remaining two apertures, which are located approximately equidistantly from the first aperture, are slot-shaped. The slots are oriented to have their long axes intersect the first aperture. Such a self adhering base is useful both as an in-process base during tube manufacture, and also as a permanent base on the finished tube. 5 Claims, 7 Drawing Figures CEL-1331 U.S. Patent Dec. 30,1986 Sheet 1 of4 4,633,132 U.S. Patent Dec. 30,1986 Sheet 2 of4 303 4,633,132 305- |i|| y-303 FIG. 3 Prior Arf FIG. 4 PriorArf U.S. Patent Dec. 30,1986 Sheet 3 of4 4,633,132 FIG. 5 U.S. Patent Dec. 30,1986 Sheet4 of4 4,633,132 FIG. 6 -W-! 60S 600 !\ r\ i/i j iS _Lf' L~-~J // ) 603^ 60/ FIG. 7 4,633,132 1 and as a permanent base during tube operation. A prin SELF-ADHERING CATHODE RAY TUBE BASE cipal obstacle to the achievement of this goal has been the lack of either a suitable adhesive or a suitable self BACKGROUND OF THE INVENTION adhering base. The time required for the curing of adhe This invention relates to bases for cathode ray tubes, sives which are fully compatible with the manufactur and more particularly relates to self-adhering bases ing process is too long to allow the realization of re which can be used both as an in-process base and a quired production speeds. Alternatively, reducing the permanent base. size of the base apertures to create an adherence suffi Cathode ray tubes, such as those used for color televi cient to withstand socket insertion and extraction forces sion and related display applications, have a glass enve 10 during processing has led to other problems. For exam lope with a face panel portion including a phosphor ple, the normal variation in pin locations among pro screen, and a neck portion oriented normal to the face duction tubes creates stresses in both the neck and the panel and containing an electron gun. In operation, the base, resulting in bent pins, cracks in the neck bottom gun generates electron beams which are swept across surrounding the glass-to-metal pin seals, and other prob the screen in a controlled manner to activate the phos 15 lems. phors and produce a display. These electron beams are A type of self-adhering base is known which replaces generated, focused and accelerated toward the screen two normally shaped apertures with slot-shaped aper by means of a series of discrete components in the gun tures smaller in width than the pins. The smaller width assembly, including at least one thermionic cathode and creates a force fit with the two mating pins, while the a series of electrodes. The beams are generated by the 20 slot shape provides a certain amount of accommodation cathode, which is activated by a heater coil. The beams for variations in pin location. However, in practice it are then focused and accelerated toward the screen by has been found that: (1) the adherence provided by the the electrodes, each of which is held at a separate elec base is insufficient to withstand the normal socket inser trical potential chosen to create the desired effect on the beams generated by the cathode. 25 tion and extraction forces encountered during tube pro cessing; and (2) the slot shaped apertures do not reduce Because the interior of the tube is held at a vacuum, the stresses sufficiently to avoid the pin problems re the electrical leads for the cathode heater and the elec ferred to above. trodes are connected to base pins sealed in the glass bottom of the tube neck. The base pins are oriented in a circular array to mate with a socket in the television chassis. In order to provide both mechanical support and electrical insulation for these base pins, the bottom of the tube neck is fitted with a plastic base designed to mate both with the pins and the tube socket. This base 30 Accordingly, it is an object of the invention to pro vide a self-adhering base for a cathode ray tube which substantially avoids the above problems while provid ing sufficient adherence to the tube pins to allow use of the base both as an in-process base and a permanent base. typically has a circular basal or bottom portion with a 35 It is a further object of the invention to provide a series of pin apertures, an upstanding cylindrical portion self-adhering base for a cathode ray tube which is easily called a "lug", and an upstanding shield portion con manufacturable, and compatible both with present cath nected to the lug and called a "silo". The basal portion ode ray tube designs and cathode ray tube manufactur supports a series of truncated cone-shaped wails sur ing processes. rounding the apertures and called "outer beads". 40 In accordance with the invention, there is provided a When the tube and base are assembled, the basal cathode ray tube base having: a bottom or basal portion portion contacts the bottom of the tube neck and the defining an array of apertures for mating with an array pins extend through the basal apertures a sufficient of cathode ray tube pins extending from the bottom of distance to mate with the socket. The silo substantially the neck of the tube, each aperture surrounded by a wall surrounds one pin which is associated with a high volt- 45 or bead upstanding from the basal portion; the base also age electrode, in order to provide arc-over protection having: a cylindrical portion upstanding from the cen for the pins. The silo has an open top to allow electrical tral portion of the basal portion; the base may also have connection of the high voltage pin with the socket. In an open-topped shield portion surrounding at least one order to provide adherence of the base to the tube, as of the pin apertures and its associated bead, for shielding well as additional electrical insulation between the pins, 50 a high voltage pin. a bead of a room temperature curable silicone resin, In accordance with the self-adhering aspects of the such as silite 100 (a trademark of DEVCON CORP.), is base, a first one of the apertures has a smaller opening typically applied to the bottom of the base in the pin than that of its associated pin, preferably a shielded area prior to assembly. aperture, and two other of the apertures are slot-shaped, In the manufacture of cathode ray tubes, it has long 55 the three apertures located approximately equidistantly been the practice to "process" the tubes after evacua from one another, and the two slot-shaped apertures tion and sealing of the tube envelope and prior to inser oriented to have their long axes intersect the approxi tion of the base. Such processing is also known as "high mate location of the first aperture. Slots are oriented in voltage conditioning" and is designed to remove small a direction to relieve the direction of stress at the stem particles and projections, particularly from the gun 60 leads. assembly, where small inter-electrode spacings would In accordance with a preferred embodiment, the otherwise be prone to high voltage arcing during later apertures are distributed in a circular array and the long tube operation. Typically, specially designed process axes of the slots form an angle with a line bisecting both bases and sockets have been used for this purpose. the first aperture and the array, the angle within the It has been recognized that considerable increases in 65 range of about 20 to 30 degrees. manufacturing efficiencies could be realized by the In accordance with another preferred embodiment, development of a cathode ray tube base which could be the side walls of the slot-shaped apertures each have a used both as an in-process base during tube manufacture planar portion and a concave conical portion, the ratio 4,633,132 34 of the slot width to its associated pin width is within the ing aperture 2096 whose function is to allow entry ofair range of about 0.37 to 0.51, which ratios have been to aid in curing of the adhesive after the base is seated. found to result in optimum pin retention force without Referring now to the self-adhering features of the undue stress on either the base, the pins, or the glass-to- base 200, there are provided two slot-shaped apertures 5 metal pin seal in the neck. 5 and 11, each having a slot width "w" less than the pin BRIEF DESCRIPTION OF THE DRAWING width by an amount sufficient to provide a force fit between the aperture and the pin. The slots are oriented FIG. 1 is a front elevation assembly view of the bot to have their long axes L and L' form an angle of about tom portion of a cathode ray tube neck and its associ 60 degrees with the centerline C of the base, said center- ated base; 10 line located to bisect apertures 1 and 8. Such orientation FIG. 2 is a top view of a self-adhering base of the prior art having two slotted apertures; accommodates a certain amount of variation in pin location from one CRT to another, so long as such FIG. 3 is a section view ofone ofthe slotted apertures variation occurs along either of the long axes L and L'. of the base of FIG. 2, the section taken along the long Referring now to FIGS. 3 and 4, section views of axis of the slot; 15 aperture 11 along lines A and B of FIG. 2, respectively, FIG. 4 is a section view of the slot of FIG. 3, taken it is seen that a portion of the inner wall 301 of bead 300 transverse to the long axis of the slot; is conically shaped at a substantially steeper angle than FIG. 5 is a top view of a self-adhering base of the that of outer wall 302. This construction is typical for all invention having a small aperture and two associated of the apertures, and serves to guide slightly misaligned slotted apertures oriented to be in line with the small 20 pins into the apertures. In FIG. 3, a pin 303 is shown in aperture; phantom partially inserted into aperture 11. The shaded FIG. 6 is a section view of one of the slotted apertures area 304 indicates the approximate area of contact be of the base of FIG. 5, the section taken along the long tween the pin and the sidewall 305 of the slot. FIG. 4 axis of the slot; and shows a pin 403 about to be inserted into aperture 11. As FIG. 7 is a section view of the slot of FIG. 6, taken 25 will be appreciated, sidewalls 305 and 306 must flex transverse to the long axis of the slot. outwardly to accommodate pin 403, due to the nar DETAILED DESCRIPTION OF THE INVENTION rower width of the slot. After insertion, the natural elasticity of the base material causes the sidewalls to reflex and hold the pin in the aperture. The flexural Referring now to FIG. 1, there is shown a front ele 30 force together with the frictional force between the pin vation assembly view of a bottom portion 100 of a CRT and the aperture in the contact area determine the total and a base 110. Bottom portion 100 includes glass neck adherent force needed to insert and extract the pin. 101 having a bottom portion 102, and a circular array of As stated above in the Background of the Invention, connector pins 103 protruding from bottom portion 102 it has been found in practice that the adherent force of a sufficient distance to make electrical contact with a 35 the above prior art design is inadequate to withstand the mating socket, not shown. The pins form glass-to-metal repeated socket insertions and extractions encountered seals 104 with the bottom 102, and protrude into the during CRT manufacture and later use. In addition, it interior of the neck's interior, where they make electri has been found that the location and orientation of the cal connections to various components of the gun as slots does not alleviate the effects of stresses caused by sembly, also not shown. Also extending from the bot 40 random pin misalignments occurring during CRT tom of the neck is exhaust tubulation 105, the remnant manufacture. of a glass tube used to exhaust the CRT during manufac A substantially improved self-adherent base in accor ture, and sealed by radiant heating at about the pin level dance with the invention is shown in top view in FIG. following exhaust. 5. Three apertures, 1, 6 and 10, are sized to produce a Base 110, fabricated from a moldable plastic composi 45 force fit with their mating pins, and are spaced approxi tion having electrical insulating properties, such as mately equidistantly from each other. Aperture 1, in the Celanex 3210 (polybutylene terephthalate from Celan- high voltage pin position, is circular, but smaller than ese Corp.) includes basal or bottom portion 107, defin the remaining circular apertures 4, 5, 7, 8, 9,11 and 12 ing a circular array of apertures sized and located for by an amount sufficient to create a force fit with its mating with the pin array, each aperture surrounded by 50 mating high voltage pin. As will be appreciated, this a supporting wall or "bead" 108, the outer surface is arrangement creates a significant adherent force due to sloped to form a truncated cone. These beads, in addi the fact that the sidewall of the bead completely sur tion to providing mechanical support, provide arc-over rounds and makes contact with the mating pin. In addi protection between adjacent pins. Extending from the tion, this tight contact forms a seal between the pin and central portion of the basal portion 107 is a cylindrical 55 the aperture which prevents Silite 100 or other adhesive portion or "lug" 109, sized and positioned to form a used between the base and the CRT neck from passing protective cover over the exhaust tubulation 105. through the aperture to cover a portion of the protrud Referring now to FIG. 2, there is shown a top view of ing pin where it could possibly interfere with the mak a type of self-adhering base 200 known in the prior art ing of a good electrical contact with the mating socket In addition to the self-adhering features to be described, 60 Located approximately equidistantly from tight aper this view shows conventional features not shown in ture 1 are two slotted apertures 6 and 10, each having a FIG. 1, such as upstanding shielding portion or "silo" width w-2 less than its mating pin width w-1 by an 210, extending from the bottom 207 of base 200 to ap amount sufficient to create a force fit between the pin proximately pin height, and extending from the lug 209 and the aperture. In accordance with one aspect of the on either side of high voltage pin aperture 1 to com 65 invention, the slots are oriented to have their long axes pletely surround the aperture and provide additional L and L' intersect aperture 1. This orientation has been protection from arc-over to adjacent aperture. Also found in practice to accommodate a considerable num shown is a conventional top cap 209a for lug 209, defin ber of variations in pin location, thus substantially alle- 64,633,132 5 viating the stress-related conditions of radial cracks in example, the number of apertures and the location of the neck glass, misaligned pins and separation of the the tight aperture and the slotted aperture may vary adhesive from the neck and base. This orientation ofthe with the intended application. slots can be further defined by the angle which the long What is claimed is: axes L and L' make with the centerline C, such angle 5 1. A self-adhering cathode ray tube base comprising: being 25 degrees 43 minutes in the embodiment shown a bottom portion defining a circular array of aper in FIG. 5. tures for mating with an array of cathode ray tube Referring now to FIGS. 6 and 7, section views of connector pins extending from the bottom of the aperture 10 along lines C and D respectively, there is neck of the tube, each aperture surrounded by a shown another aspect of the invention in which the 10 wall upstanding from the bottom portion, and first contact area 604 is significantly increased over that of and second ones of the apertures being slot-shaped; the prior art base of FIG. 3. This is accomplished by and decreasing the angle "f' defining the slope of the coni a cylindrical portion upstanding from the central cal portion 601 of the aperture sidewall 602. Because of portion of the bottom portion, for forming a pro this increase in the contact area between the pin and the 15 tective cover for an exhaust tabulation extending aperture, the frictional component of the adherent force from the bottom of the neck; is also increased, thus improving the overall self-adher characterized in that a third one of the apertures has ence of the base. a smaller opening than that of its associated pin, Since in practice, it is difficult to measure the actual and the two slot-shaped apertures oriented to have area of contact between the aperture and the pin, the 20 their long axes intersect the approximate location ratio of the height "h-1" of the cone vertex to the height of the third aperture to form an angle with a line "h-2" of the planar portion 605 of the sidewall 602 can bisecting both the third aperture and the array, the be used as an indication of such area, since such ratio is angle within the range of about 20 to 30 degrees. proportional to such contact area for a given pin width. 2. The base of claim 1 including a shield portion sur For specific applications, it will be necessary to select 25 rounding at least one of the pin apertures and its associ a combination of slot width w-1, pin width w-2, cone ated wall, for shielding a high voltage pin. vertex height h-1 and sidewall height h-2 to achieve the 3. The base of claim 1 in which the first aperture is desired insertion and extraction forces. In general, a surrounded by the shield portion. ratio of slot width w-1 to pin width w-2 within a range 4. The base of claim 1 in which the slot-shaped aper of from about 0.66 to 0.80, and a ratio of cone height h-1 30 tures have slots of width "w-1", such width "w-1" hav to sidewall height h-2 within the range of about 0.37 to ing a ratio to width "w-2" of the associated pin within 0.51 will result in an extraction force of from about 9 to the range of about 0.66 to 0.80, and in which the slot 13 pounds, which will be found to be satisfactory for shaped apertures have sidewalls including a conical most applications. In the specific embodiment shown, a portion of height "h-1" and a planar portion of height slot width w-1 of about 0.029 Inch, a pin width W-2 of 35 "h-2", such height "h-1" having a ratio to height "h-2" about 0.039 Inch, a cone height h-1 of about 0.048 Inch, within the range of about 0.37 to 0.51 which ratio is and a sidewall height h-2 of about 0.108 Inch, result in proportional to the contact area between the apertures ratios of about 0.74 and 0.44 respectively, and an extrac and their associated pins. tion force of about 11 pounds. 5. The base of claim 1 in which a layer of adhesive is While there have been shown and described what are 40 located between the bottom of the tube neck and the at present considered to be the preferred embodiments bottom of the base, at least in the area surrounding the of the invention, other embodiments are intended to be included within the scope of the appended claims. For high voltage apertur*e a*nd i*ts a*sso*ciated pin. 45 50 55 60 65