EP0355124B1 - Process and apparatus for the manufacture of cathode ray tubes having tension masks - Google Patents

Process and apparatus for the manufacture of cathode ray tubes having tension masks Download PDF

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Publication number
EP0355124B1
EP0355124B1 EP88905282A EP88905282A EP0355124B1 EP 0355124 B1 EP0355124 B1 EP 0355124B1 EP 88905282 A EP88905282 A EP 88905282A EP 88905282 A EP88905282 A EP 88905282A EP 0355124 B1 EP0355124 B1 EP 0355124B1
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EP
European Patent Office
Prior art keywords
frame
mask
shadow mask
faceplate
tension
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
EP88905282A
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German (de)
English (en)
French (fr)
Other versions
EP0355124A1 (en
Inventor
Paul Strauss
John Jarosz
James Fendley
Lawrence W. Dougherty
James L. Kraner
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.)
Zenith Electronics LLC
Original Assignee
Zenith Electronics LLC
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
Priority claimed from US07/051,896 external-priority patent/US4790786A/en
Priority claimed from US07/139,892 external-priority patent/US4894037A/en
Priority claimed from US07/140,019 external-priority patent/US4934974A/en
Priority claimed from US07/139,997 external-priority patent/US4840596A/en
Application filed by Zenith Electronics LLC filed Critical Zenith Electronics LLC
Priority to AT88905282T priority Critical patent/ATE88595T1/de
Publication of EP0355124A1 publication Critical patent/EP0355124A1/en
Application granted granted Critical
Publication of EP0355124B1 publication Critical patent/EP0355124B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • H01J9/22—Applying luminescent coatings
    • H01J9/227—Applying luminescent coatings with luminescent material discontinuously arranged, e.g. in dots or lines
    • H01J9/2271—Applying luminescent coatings with luminescent material discontinuously arranged, e.g. in dots or lines by photographic processes
    • H01J9/2272—Devices for carrying out the processes, e.g. light houses
    • 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
    • H01J29/06—Screens for shielding; Masks interposed in the electron stream
    • H01J29/07—Shadow masks for colour television tubes
    • H01J29/073—Mounting arrangements associated with shadow masks
    • 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

Definitions

  • This invention relates to color cathode ray picture tubes, and is addressed specifically to improved factory means and processes for the manufacture of tubes having a tensed foil shadow mask.
  • Color tubes of various types that have a tension foil mask can be manufactured by the process, including those used in home entertainment television receivers.
  • the process according to the invention is particularly valuable in the manufacture of medium-resolution, high-resultion, and ultra-high resolution tubes intended for color monitors.
  • the use of the foil-type flat tensed mask and flat faceplate provides many benefits in comparision to the conventional domed shadow mask and correlatively curved faceplate. Chief among these is a greater power-handling capability which makes possible as much as a three-fold increase in brightness.
  • the conventional curved shadow mask which is not under tension, tends to "dome" in picture areas of high brightness where the intensity of the electron beam bombardment is greatest. Color impurities result as the mask moves closer to the faceplate and as the beam-passing apertures move out of registration with their associated phosphor elements on the faceplate.
  • the tensed mask when heated distorts in a manner quite different from the conventional mask.
  • the tensed foil shadow mask is a part of the cathode ray tube front assembly, and is located in close adjacency to the faceplate
  • the front assembly comprises the faceplate with its screen which consists of deposits of light-emitting phosphors, a shadow mask, and support means for the mask.
  • shadow mask means an apertured metallic foil which may, by way of example, be about 25 ⁇ m (0.001 inch) or less in thickness.
  • the mask must be supported under high tension a predetermined distance from the inner surface of the cathode ray tube faceplate; this distance is known as the "Q-distance.”
  • the shadow mask acts as a color-selection electrode, or parallax barrier, which ensures that each of the three electron beams lands only on its assigned phosphor deposits.
  • the conventional process of depositing patterns of color phosphor elements on the screening surface of a color picture tube faceplate utilizes the well-known photoscreening process.
  • a shadow mask which in effect functions as a perforated optical stencil, is used in conjunction with a light source to expose in successive steps, three discrete light-sensitive photo-resist patterns on the screening surface.
  • the shadow mask is typically "mated" to each faceplate; that is, the same mask is used in the production of a specific tube throughout the production process, and is permanently installed in the tube in final assembly. At least four engagements and four disengagements of the mask, as well as six exposures, are required in the standard screening process.
  • a "master" may be used for exposing the photoresist patterns in lieu of the mated shadow mask.
  • a method of making a color cathode ray tube in which a frame on which a shadow mask is stretched has indexing means cooperable with registration-affording means on a faceplate.
  • the assembly provides for multiple registered matings of the faceplate and mask during photoscreening operations.
  • a photographic plate is used in a process for applying the phosphor elements to the faceplate screening surface to provide an interchangeable mask system; this in lieu of the more common method of using a shadow mask permanently mated with a faceplate, and which serves as an optical stencil during the photo-screening process.
  • the sealing areas of the faceplate and the frame are joined in a final assembly operation such that the frame becomes an integral constituent of the cathode ray tube.
  • a mask registration and supporting system for a cathode ray tube having a rounded faceplate with a skirt for attachment to a funnel is disclosed by Strauss in U.S. Patent No. 4,547,696.
  • the skirt of the faceplate provides the necessary Q-distance between the mask and the screen.
  • a frame dimensioned to enclose the screen comprises first and second spaced-apart surfaces.
  • a tensed foil shadow mask has a peripheral portion bonded to a second surface of the frame.
  • the frame is registered with the faceplate by ball-and-groove indexing means.
  • the shadow mask is sandwiched between the frame and a stabilizing or stiffening member. Following final assembly, the frame is permanently fixed in place within the tube envelope between the sealing lands of the faceplate and a funnel, with a stiffening member projecting from the frame into the funnel.
  • a shadow mask mount in the shape of a rectangular frame for use in tensing an in-process shadow mask, and for temporarily supporting the mask while in tension.
  • An apertured foil comprising the in-process mask is laid across the opening in the frame and is secured to the frame by brazing or welding.
  • the coefficient of thermal expansion of the foil is preferably equal to or slightly less than that of the frame.
  • a glass frame is also provided that consists of two identical rectangular members smaller in circumferential dimension than the metal frame. When joined into a single frame, the members are located between the tube faceplate and funnel to become an integral part of the tube envelope in final assembly.
  • Each member of the glass frame has indexing means, one member for indent-detent registration with the faceplate, and the other for indent-detent registration with the funnel.
  • the portion of the mask that projects beyond the periphery of the glass frame is severed to release the metal frame.
  • the glass frame with its captivated mask is then mounted on a lighthouse for photoscreening the faceplate, with registration with the lighthouse and faceplate provided by the indent-detent means described.
  • a flat tensed mask on a frame for use in a color cathode ray tube having a circular faceplate with a curved viewing surface.
  • the mask which is also circular, is described as being welded to a circular frame comprised of a 3.2 mm (1/8-inch) steel section.
  • the frame with captivated mask is mounted in spaced relationship to a phosphor-dot plate, and the combination is assembled into the tube as a package located adjacent to the faceplate.
  • U.S. Patent No. 3,894,321 to Moore which is more pertinent prior art is directed to a method for processing a color cathode ray tube faceplate in conjunction with a thin foil tension shadow mask.
  • a frame screw-clamp supports a tensed mask during lighthouse exposure of an associated screen.
  • the faceplate is registered with the mask support frame by means of three alignment posts which extend from the lighthouse, and against which the frame and the faceplate are both biased by gravity.
  • the faceplate and frame being both reference to the three lighthouse posts, are thereby referenced to each other.
  • this invention aims to provide means to facilitate the manufacture of color cathode ray tubes having a tensed foil shadow mask by providing improved fixturing means that will greatly facilitate this manufacture.
  • the present invention therefore provides a factory fixture frame for mounting an in-process shadow mask for use in the manufacture of a color cathode ray tube having a flat faceplate and a tensed foil shadow mask said shadow mask having a predetermined pattern of apertures therein and said faceplate having registration affording means externally of the tube, said frame including a generally rectangular frame means defining a central opening, indexing means associated with said frame and cooperable directly with the registration affording means of an in-process faceplate, and means for removably securing said shadow mask in tension on said frame across said frame opening whereby said frame is adapted for temporarily mounting and conveying an in-process shadow mask for processing by manufacturing machinery.
  • a related aim is to provide an improved process for the manufacture of color cathode ray tubes.
  • the present invention therefore provides a process for use in the manufacture of a color cathode ray tube having a flat faceplate and a tensed foil shadow mask, said process including the steps of providing a reusable, generally rectangular factory fixture frame having releasable mask-retaining means, temporarily and removably supporting an in-process shadow mask in tension on said frame with said releasable mask-retaining means, providing an in-process faceplate having indexing means extending from the side thereof for registration with indexing means extending internally from said factory fixture frame, providing a shadow-mask-supporting structure and securing said structure to the screen-bearing surface of said faceplate on opposed sides of the screen, affixing said in-process shadow mask in tension to said supporting structure, and severing the combined mask-faceplate assembly from said frame thereby releasing said frame for reuse.
  • indexing means is associated with the frame and cooperated directly with the registration affording means.
  • the registration affording means extend from the side of the in-process faceplate for registration with indexing means extending internally from the frame.
  • the known frame of U.S. Patent 3,894,321 has indexing means associated with the lighthouse so that the frame and the faceplate are indexed indirectly through the lighthouse.
  • the alignment posts functioning as registration affording means extend from the lighthouse rather than from the side of the faceplate.
  • Another feature of the invention is the provision of a factory fixture frame that is capable of highly precise and repeatable two-sided registration with a lighthouse and a faceplate during faceplate photoscreening, and precise registration with a mask-welding and severing machine.
  • Still another feature of the invention involving a factory fixture frame including tensed foil in-process shadow mask clamping means for quickly and securely clamping and retaining a shadow mask under high tension without damage to the mask.
  • the factory fixture frame of the invention is rigid in construction, reusable, and relatively light in weight for easy handling.
  • a color cathode ray tube 20 having a tensed foil shadow masks is shown by Figure 1.
  • the front assembly 22 of tube 20 includes a faceplate 24.
  • a film of aluminum 30 is indicated as covering the screen 28.
  • the peripheral sealing area 32 of faceplate 24 is depicted as being attached to the peripheral sealing area 33 of a funnel 34.
  • Front assembly 22 includes a shadow mask support structure 48 for mounting a metal foil shadow-mask 50 which is secured to support structure 48 in tension.
  • the anterior-posterior axis of tube 20 is indicated by reference number 56.
  • a magnetic shield 58 is shown as being enclosed within funnel 34.
  • High voltage for tube operation is indicated as being applied to a conductive coating 60 on the inner surface of funnel 34 by way of an anode button 62 connected in turn to a high-voltage conductor 64.
  • the neck 66 of tube 20 is represented as enclosing an in-line electron gun 68, depicted as providing three discrete in-line electron beams 70, 72 and 74 for exciting respective red-light-emitting, green-light-emitting, and blue-light-emitting phosphor elements on screen 28.
  • Yoke 76 receives scanning signals and provides for the scanning of beams 70, 72 and 74 across screen 28.
  • a contact spring 78 provides an electrical path between the funnel coating 60 and mask support structure 48.
  • the factory fixture frame according to the invention provides for the high precision in the registration and re-registration of a foil in-process shadow mask with a faceplate during manufacture. Absent the requisite precision, an error in registration of as little as 5 ⁇ m (0.0002 inch) can result in color impurities.
  • Mask 50 typically may have about 1,700,000 apertures, and the resulting screen 28, after photoscreening by means of the factory fixture frame according to the invention, will have three times as many discrete phosphor deposits thereon. There is an absolute minimum of tolerance in registration at any stage of the production process.
  • a reusable factory fixture frame 82 according to the invention is shown in Figure 2; a first side 84 of frame 82 is indicated.
  • the frame 82 is intended for use in the manufacture of a color cathode ray tube of the type shown by Figure 1, which is noted as having a flat faceplate and a tensed foil shadow mask.
  • Factory fixture frame 82 provides for mounting an in-process shadow mask during photoexposure of an in-process faceplate in a lighthouse, and serves as a fixture for the process of welding and severing the in-process mask, as will be described.
  • reusable factory fixture frame 82 comprises a generally rectangular frame means and quick-release mechanical mask-retaining means for temporarily and removably supporting in-process shadow mask 86 in tension.
  • Frame 82 is indicated as supporting shadow mask 86 in tension by means of mechanical mask-retaining means 88.
  • Factory fixture frame 82 provides for the cementless and weldless quick-retention of in-process shadow mask 86 out of the plane of mask 86.
  • the factory fixture frame 82 will be noted as having handles 90A, 90B and 90C for convenience in handling during manufacture. Handles 90A and 90B provide for lifting the frame, and handle 90C provides for inserting and removing the factory fixture frame 82 from the mask tensing-clamping machine 96 depicted in Figure 3.
  • the mask tensing-clamping machine 96 provides for receiving the factory fixture frame 82, which is loaded into the mask tensing-clamping machine 96 by an operator using the handles described; the factory fixture frame 82 is indicated in Figure 3 as being mounted in machine 96, and ready to tense and clamp an in-process shadow mask. Machine 96 is indicated as having an upper platen 100 and a lower platen 102. The platens are heated to provide for expansion of the mask blank prior to the clamping operation.
  • In-process mask 86 comprises a center field 104 of apertures intended for the color selection function in the completed tube. Center field 104 is indicated as being enclosed by a frame 106 of unperforated metal; this frame is trimmed off in a later operation at trim line 108, indicated by the dash line, by means that will be described. In-process mask 86 is indicated as having a round perforation 109 in frame 106, and an elongated perforation 110 opposite. As depicted in Figure 5, the perforations 109 and 110 provide for registering the in-process mask 86 with respective pins 112 and 114 that project from lower platen 102. The elongated perforation 110 provides tolerance for the expansion of the in-process mask resulting from its contact with the heated platens 100 and 102, an expansion that is on the order of 0.8 mm (0.030 inch).
  • the in-process mask 86 When the in-process mask 86 is fully expanded by the heat of upper and lower platens 100 and 102, the mask is clamped, and the platens are withdrawn. The mask tenses as it cools, and it is held in tension by the clamping means 88 that are a component of factory fixture frame 82, as will be described.
  • Factory fixture frame 82 has two sides of interest: first side 84, depicted in Figures 2, 6 and 10 and a second side 118, depicted in Figures 7 and 8.
  • first six-point indexing means on first side 84 provide for registration with complementary registration-affording means on an exposure lighthouse 122
  • second six-point indexing means on an opposed second side 118 provide for registration with complementary registration-affording means on an in-process faceplate 120.
  • in-process shadow mask 86 can be precisely registered and re-registered with lighthouse 122 and an in-process faceplate 120 while retaining the in-process shadow mask 86 in tension.
  • the first six-point indexing means on the first side 84 also provide for registering the frame 82 and in-process shadow mask 86 with mask tensing and clamping means, noted as being machine 96, which has complementary six-point indexing means, as will be described.
  • the clamping means 88 for clamping and holding in-process mask 86 in tension is depicted in Figure 6 as being in the form of a series of discrete spring clip means which provide for mechanically clamping the mask in tension.
  • the preferred spring clip means for clamping the in-process mask in tension will be described hereinafter in greater detail with reference to Figs. 12 to 24 of the drawings.
  • the factory fixture frame, while clamping the tensed in-process mask, is removed from the mask tensing-clamping machine 96 in readiness for subsequent photoexposure and screening operations, as will be described.
  • Photoexposure lighthouse 122 is illustrated schematically in Figure 8 as comprising a base 124 within which is a light source 126 that emits ultraviolet radiation to which the various screening fluids are sensitized.
  • the rays of the light source 126 typically pass through a correction lens and a neutral density filter (not shown) before reaching the shadow mask.
  • a table top 128 provides for mounting a platform 130 for receiving factory fixture frame 82.
  • the six-point indexing means is depicted by way of example as comprising ball-and-groove means located on the parts to be registered. Although ball-and-groove indexing means are depicted for this means of indexing in this, and in subsequent depictions, it is noted that other means of indexing may as well be used.
  • factory fixture frame 82 With reference to the first side 84 of factory fixture frame 82, three groove means 132A, 132B and 132C are shown; these groove means provide for registration with three ball means 134A, 134B and 134C located on platform 130 of lighthouse 122. As indicated by Figure 8, the factory fixture frame 82 according to the invention is lowered into registration with the lighthouse 122 for exposing the screening surface of in-process faceplate 120 to radiation from light source 126.
  • Groove means 132A, 132B and 132C also provide for the registration of factory fixture frame 82 with the mask tensing-clamping machine 96 in conjunction with six-point indexing means 135A, 135B and 135C depicted in Figure 3 as being in the form of ball means projecting from the lower platform 137 of machine 96. (Ball means 135C is not visible in Figure 3.)
  • Factory fixture frame 82 according to the invention is noted as having on its second side 118, second six-point indexing means for registering with complementary registration-affording means on the in-process faceplate 120.
  • the indexing means are indicated as comprising ball-and-groove means located on the parts to be registered.
  • three groove means 136A, 136B and 136C are depicted; these groove means provide for registration with three balls means 138A, 138B and 138C extending from the sides of faceplate 120, as depicted in Figure 9.
  • the ball means 138A, 138B and 138C comprise temporary indexing means.
  • the cement used for attachment of the temporary indexing means is of the type that becomes non-adherent at the frit cycle temperature of 435 degrees C. As a result, the ball means fall away from the faceplate at the time of final assembly.
  • At least one of the sides of the factory fixture frame according to the invention has at least first and second six-point indexing means azimuthally rotated with respect to each other for indexed mating with complementary six-point indexing means on manufacturing machinery, with the manufacturing machinery noted as being a lighthouse in this phase of the process.
  • Plastic guides 140 provide for guiding in-process faceplate 120 into recess 141 of factory fixture frame 82, with the final, precision registration being provided by grooves 136A, 136B and 136C in registery with ball means 138A, 138B and 138C that extend from in-process faceplate 120.
  • In-process faceplate 120 has on its inner surface 142 a screening area 144 for receiving discrete deposits of phosphors.
  • a shadow mask support structure 146 has surface 148 for receiving and securing in-process shadow mask 86 in tension by means to be described.
  • the photoscreening process then follows.
  • the inner surface 142 of the in-process faceplate 120 is first coated with a light-sensitive material.
  • the factory fixture frame 82 according to the invention with the in-process shadow mask mounted in tension therein, is installed on the platform 130 of lighthouse 122, with precise registration of the first side 84 of frame 82 being provided by groove means 132A-C in conjunction with ball means 134A-C, which are located on lighthouse platform 130.
  • the in-process faceplate 120 is in turn mounted on the factory fixture frame in precise registration with the captivated mask using groove means 136A-C on the second side 118 of frame 82 in conjunction with ball means 138A-C that extend from the sides of faceplate 120.
  • the screening surface 142 of faceplate 120 is exposed to light actinic to the coating through each of the apertures in the in-process mask 86. Faceplate 120 is then removed from lighthouse 122 to "develop" the coating. As a result of the preceding steps, a "grille" is formed on the screening surface 142 which has three open areas in correlation to each aperture of the shadow mask. The opening provide for receiving sequential deposits of red-light-emitting, green-light-emitting and blue-light-emitting phosphors.
  • the faceplate is coated with a slurry containing phosphor which may comprise, by way of example, a phosphor that emits red light when excited by an electron beam.
  • the faceplate is replaced in the lighthouse in precise registration with the in-process shadow mask, and the coating is exposed to light projected through the apertures of the mask from a light source located at a position that corresponds to the emission point of the particular electron beam that is intended to excite the red-light-emitting phosphor.
  • the light in effect, "hardens" the phosphor so that it will remain in place during a subsequent washing process.
  • the foregoing steps are repeated in turn to deposit the green-light-emitting phosphor and the blue-light-emitting phosphor in the respective openings in the grille. At least four such engagements and disengagements of the mask are required in the screening process.
  • the final product is a faceplate having on its screening area 144 a pattern of groups of dots or lines capable of emitting upon excitation by electron beams red, green or blue light; this area comprises the screen 145. It is to be noted that, in this process, an in-process shadow mask is typically "mated" with an in-process faceplate; that is, the same mask is used in-the photoscreening of a particular faceplate, and is permanently installed in conjunction with the faceplate in final assembly.
  • the in-process shadow mask 86 is affixed to the mask-receiving surface 148 of the shadow mask support structure 146, and the mask 86 is removed from the factory fixture frame 82.
  • the apparatus and process is described in the following paragraphs in some detail in connection with Figures 7, 10 and 11 to facilitate a fuller understanding of the form and function of the factory fixture frame according to the invention.
  • the second side 118 of factory fixture frame 82 is depicted as having third six-point indexing means 152A, 152B and 152C, depicted as being in the form of radially oriented grooves.
  • Second side 118 is also depicted as having fourth six-point indexing means 154A, 154B and 154C, depicted as being in the form of ball means projecting from frame 82.
  • Third and fourth six-point indexing means provide for gross and fine registration, respectively, of factory fixture frame according to the invention and an in-process mask with assembly means for affixing the mask to mask-support means extending from and secured to the faceplate, as will be shown and described.
  • a receiving fixture 156 which is a part of a mask welding and severing machine (not shown).
  • the machine includes a carousel which rotates to four stations in the process of welding an in-process shadow mask held in tension in the factory fixture frame to a mask support structure, and severing the resulting mask-faceplate assembly from the frame.
  • the factory fixture frame is released for the temporary installation of a new in-process mask, and the faceplate assembly is released for attachment to a funnel.
  • Receiving fixture 156 is indicated as having three indexing means 158A, 158B and 158C represented as being in the form of ball means extending upwardly from fixture 156.
  • Indexing means 158A, 158B and 158C provide for indexing with complementary six-point third indexing means 152A, 152B and 152C located on the second side 118 of factory fixture frame 82 (see Figure 7); indexing means 152A, 152B and 152C are indicated as being in the form of radially oriented grooves.
  • indexing means provide for the gross registration of the factory fixture frame 82 and the enclosed in-process shadow mask 86 with the mask welding and tensing machine. Installation of the frame 82 on receiving fixture 156 is accomplished manually by means of the handles 90A, 90B and 90C.
  • the precise configuration of the shadow mask receiving surface 148 in relation to the ball means 138A-C of the in-process faceplate 120 is mapped by optical means in the second station (not shown) of the mask welding and severing machine.
  • the receiving fixture 156, with thee factory fixture frame 82 mounted thereon, is then rotated to a third station of the mask welding and severing machine along with the in-process face-plate 120.
  • fine registration means are brought into play to ensure exact and precise registration of the clamped-in mask with in-process faceplate 120, and to present the mask receiving surface 148 in a precise relative relationship in order to utilize the above-described mapping information to effectively drive the welding head at the masks welding and severing machine.
  • the fourth "fine" registration means comprise six-point indexing means 154A, 154B and 154C, depicted as comprising three ball means extending from the second side 118 factory fixture frame 82.
  • six-point indexing ball means 154A, 154B and 154C are the associated six-point indexing means 160A, 160B and 160C, indicated in Figure 10 as comprising groove means located atop respective ram heads 161A, 161B and 161C all three of which are mounted on a platform and raised and lowered in synchronism by a pneumatic piston (the platform and piston are not shown).
  • factory fixture frame 82 has two related sets of six-point indexing means: the first of the sets provides for transporting frame 82 into a gross position relative to an operation utilizing the in-process mask, noted as being a laser mask welding and severing operation.
  • the second of the sets provides for positioning of the factory fixture frame 82 in the welding and severing operation such that when the in-process faceplate 120 is brought into registry with the frame through the conjunction of ball means 138A-C on the faceplate with the groove means 136A-C on the frame, the faceplate is so located that the welding head can "find" the mask mounting surface 148 according to the stored mapping information obtained in the mapping station.
  • mating of the faceplate ball means 138A-C with the groove means 136A-C on the factory fixture frame assures precise registry at the screen 145 with the center field of apertures 104 of the clamped mask during the welding and severing operation.
  • ball means 154A, 154B and 154C also provide for precise registration of the factory fixture frame 82 with a frame carrier and hence precise positioning and mounting of the in-process shadow mask in the factory fixture frame according to the invention.
  • Ram heads 161A and 161B (in conjunction with ram head 161C which is not shown) are indicated as having lifted factory fixture frame 82 from the gross position wherein the frame 82 was resting on ball means 158A, 158B and 158C of receiving fixture 156 by the conjunction of the ball means with groove means 152A, 152B and 152C.
  • the clamping of mask 86 in frame 82 is indicated schematically by arrow 88A.
  • Faceplate 120 is depicted as resting on carriage 162, indicated symbolically as being made of a plastic. A plastic softer than the glass of the faceplate is preferred as a carrier as it will not scratch or otherwise abrade the polished surface of the faceplate.
  • carriage 162 can be raised and lowered by the pneumatic piston 163, depicted in Figure 11A as being in the lowered position.
  • Figure 11B depicts in-process faceplate 120 as having been lifted by piston 163 into exact registration with factory fixture frame 82 and with the in-process shadow mask 86 contained therein.
  • the means of registration of the in-process faceplate with the factory fixture frame are indicated as comprising the conjunction of ball means 138a, 138b (and 138C, not shown) that extend from faceplate 120 with groove means 136A, 136B, (and 136C not shown) that extend inwardly from factory fixture frame 82.
  • the mask-receiving surface 148 of shadow mask support structure 146 is indicated in Figure 11B as being in intimate, uniform contact with the shadow mask 86.
  • the mask 86 could as well be in a negative interference relationship with the mask-receiving surface 148 mask support structure 146.
  • the in-process mask 86 is welded to mask receiving surface 148 of the shadow mask support structure 146; the weld line 164 is indicated in Figures 4 and 10.
  • Welding is preferably accomplished with the beam of a carbon dioxide laser.
  • the welding process is indicated schematically in Figure 11B by arrow 166 which represents the laser beam.
  • the power of the beam is reduced and the frame 106 of unperforated metal of in-process shadow mask 86 is severed at trim line 108, indicated by the arrow; the trim line 108 is, also indicated in Figures 4 and 10.
  • the in-process shadow mask now secured to mask support structure 146, is free of the factory fixture frame 82, and the assembly has become a viable faceplate assembly complete with a phosphor-bearing screen 145, and ready for attachment to a funnel.
  • the attachment of a faceplate assembly to a funnel is depicted in Figure 1.
  • the factory fixture frame 82 is reinstalled in the mask tensing-clamping machine 96, and the remainder of the mask 86 that is still clamped in the frame 82, that is, the frame 106 of unperforated metal, is removed from the frame, and a new in-process mask is tensed and clamped in the frame.
  • the cycle of faceplate photoscreening, and mask welding and severing, is then repeated.
  • the process according to a preferred aspect of the invention for use in the manufacture of a color cathode ray tube having a flat faceplate and a tensed foil shadow mask comprises the following-- providing a reusable, generally rectangular factory fixture frame having quick-release mechanical mask-retaining means; temporarily and removably supporting an in-process shadow mask in tension on the frame by the mechanical mask-retaining means; providing on a first side of the frame six-point indexing means and, using the indexing means, registering the frame and the mask with a photoexposure lighthouse having complementary six-point indexing means; providing on a second, opposed side of the frame six-point indexing means, and registering the frame and the mask with means for affixing the mask to a mask-supporting structure on the faceplate; affixing the mask to the mask-supporting structure; and severing the combined mask and faceplate assembly from the frame thereby releasing the frame for reuse.
  • third and fourth six-point indexing means are provided on the second side 118 of factory fixture frame 82 for gross and fine registration, respectively, of the frame 82 according to the invention, and the in-process mask 86, with complementary six-point indexing means on the mask welding and severing machine.
  • the material of which the factory fixture frame is made provide a structure that is reusable, rigid in construction, and yet relatively light in weight for easy handling.
  • a preferred material is cast stainless steel which provides the necessary rigidity and corrosion resistance.
  • the lightness of the factory fixture frame according to the invention is due to its construction, in that it is cast in the form of thin main members supported by numerous gussets.
  • the factory fixture frame is made reusable by virtue of the fact that the frame 106 of unperforated metal of the in-process shadow mask is not permanently secured to the factory fixture frame by means such as welding, but instead, by quick-release mechanical means according to the invention.
  • Components of the six-point indexing means such as groove means and ball means are necessarily hardened to limit the effects of physical wear and the trauma of physical shock and impact inherent in the positioning and retrieving of the frame by hand during production.
  • Figures 12-24 disclose further aspects of the invention including the preferred form of quick-release mechanical mask-retaining means for use on the reusable factory fixture frame to temporarily and removably support the in-process shadow mask in tension.
  • FIGs 12-14 show the details of the clamping means in the form of spring clips 218, 218' embodying the concepts of the invention.
  • Figures 15 and 16 show a factory fixture frame 220 which functions like frame 82 of Figures 6 and 7 for precisely registering and re-registering a foil in-process shadow mask with a faceplate during manufacture.
  • a plurality of spring clips 218 are employed in rows along each side of frame 220 for clamping the mask foil.
  • factory fixture frame 220 like frame 82 provides for mounting an in-process shadow mask 222 during photoexposure of an in-process faceplate in a lighthouse, and serves as a fixture for the process of welding and trimming the in-process mask.
  • the factory fixture frame is reusable and comprises a generally rectangular frame means and a quick-release mechanism comprising mask-retaining means (i.e. spring clips 218) for temporarily and removably supporting an in-process shadow mask 222 in tension by means of the spring clips 218.
  • the factory fixture frame provides for a cementless and weldless quick-retention of an in-process shadow mask 222.
  • factory fixture frame 220 includes receptacle means in the form of grooves 224 (Fig.
  • the spring clips comprise a quick-release mechanical mask-retaining means for securing the shadow mask in tension in the receptacle means formed by grooves 224.
  • the mask tensing-clamping machine 96 receives the factory fixture frame 220 which is loaded into the machine by an operator in a manner similar to the loading of frame 82 .
  • the machine also provides for receiving a shadow mask 222 in a free state between the upper and lower platens 100 and 102, respectively.
  • the platens are heated to elevate the temperature of shadow mask 222 as the platens sandwich the mask therebetween, which sandwiching serves principally to flatten the mask and render it wrinkle-free. Edges 226 of the shadow mask are clamped into grooves 224 by spring clips 218 of the factory fixture frame while the shadow mask is heated.
  • the edge-clamped shadow mask then is allowed to cool and shrink into tension while being temporarily and removably supported in this state, on frame 220 by spring clips 218.
  • the frame, with its tensed shadow mask, then is ready to be transported through other processing steps, such as the aforesaid photoexposure of an in-process faceplate in a lighthouse.
  • each spring clip 218 includes a relatively strong, generally U-shaped outer spring 228 and a generally U-shaped inner spring 230 of lesser strength.
  • a pair of shoes 232 of inverted, generally L-shapes are positioned over the distal ends of U-shaped Spring 228, as shown in Figures 12 and 14.
  • Locating pins, generally designated 240 extend freely through concentrically disposed apertures in shoes 232 and the legs of spring 228, see Figures 12 or 14.
  • each pin 240 has a reduced end 240a which extends through the respective shoe 232 and an enlarged end 240b which abuts the outwardly directed face of its assigned shoe and extends through aperture 242 in the adjacent leg of spring 228.
  • U-shaped inner spring 230 are bifurcated and located on ends 240a of pins 240 while, at the same time, apply a biasing force against the inside surfaces of shoes 232 in opposing directions, as indicated by arrows "B" (Fig. 12).
  • the combination of the biasing spring 230, and the cooperative structure of shoes 232 combine to provide a "floating" or “lost-motion” action for shoes 232 to enable the shoes to yield and wipe the edge of the shadow mask as a spring clip 18 is inserted into groove 224 in the factory fixture frame, all in a manner to be described.
  • spring clip 218' of Figure 14 differs from clip 218 of Figures 12 and 13 only in that the pin 240 assigned to the leg of left shoe 252 (as viewed in Figure 14) is welded, or otherwise fixed to the left leg of U-spring 228. This weld is identified by reference numeral 241. This effectively immobilizes the left shoe 232, for a purpose to be explained below.
  • machine 96 is seen to include rows of actuating mechanisms, generally designated 244, about the periphery of the four sides of lower heater platen 102. At least portions of these mechanisms are shown in Figures 17-24 and are provided to effect closing and opening of spring clips 218. As shown in Figures 17 and 18, one such actuating mechanism 244, is provided for closing and opening an adjacent pair of spring clips 218.
  • the actuating mechanisms are operated by pneumatic piston and cylinder devices 246 which respond to the control center that governs the cyclic operation of machine 96.
  • Each actuating mechanism 244 includes a scissors-type spring clip closing device, or grippers, generally designated 248, a cam wedge 250, and a pneumatic piston and cylinder device 246.
  • Scissors device 248 includes a pair of arms 248a pivoted intermediate their ends, as at 252, to define opposed jaws 254, at one end of the scissors device, and actuating arms 256 at the opposite end.
  • a removable rub pad 255 is fastened atop each of jaws 254 to engage the underside of the associated shoe 232, see Figure 19. This arrangement serves to prevent bight of U-spring 228 from bottoming against jaws 254 and being removable they can be replaced when worn, rather than replace an entire scissor arm 248a.
  • each gripper jaw 254 contains a pair of cavities 275 to generally locate each spring clip assembly 218 along the four rows of scissors assemblies 248.
  • a tension spring 258 is disposed between actuating arms 256 to bias the arms inwardly and, thereby, jaws 254 to an open position.
  • a pair of follower rollers 260 are journalled within the bottom of actuator arms 256 for engaging either of two dwell surfaces 250a, 250b, on a cam wedge 250, as described hereinafter.
  • Cam wedge 250 is coupled to a plunger or extension 262 of the piston portion of the piston and cylinder device 246.
  • a biasing coil spring 264 surrounds plunger 262.
  • cam wedge 250 An upward displacement of cam wedge 250 from an initial position ( Figure 17), in which cam dwell surface 250a is in engagement with roller 260, to an elevated position ( Figure 19), in which dwell surface 250b engages roller 260, spreads actuator arms 248a outwardly in the direction of arrows "C” to cause a pivotal displacement of jaws 254 about point 252 inwardly in the direction of arrows "D". Since jaws 254 are in engagement with spring clip 218, an inward movement of the jaws is effective to drive the legs of U-shaped spring 228 inwardly to close the spring clip and effect inward movement of shoes 232 in the direction indicated by arrows "E", see Figure 19.
  • actuating mechanism 244 is depicted in Figure 19 and this action, in conjunction with the mask clamping function of the upper and lower heater platens 100 and 102 of machine 96 serve to clamp the edges 226 of mask 222 in the receptacle grooves 224 of the factory fixture frame 282.
  • Figure 17 shows the aforesaid components in a condition wherein cam wedge 250 is lowered, gripper jaws 254 are open, as is spring clip 218 and actuating mechanism 244 is in its deenergized condition.
  • FIG 19 a factory fixture frame 220 has been inserted in the central opening in the Figure 3 machine 96 and is supported by loading rollers 266 (only one shown).
  • a foil mask 222 is placed upon the lower heater platen 102 and indexed thereon by a pair of mask locating pins 268. One of these pins enters a hole 222h in the mask while the other pin is received in a mask slot 222s, see Figure 19.
  • Upper heater platen 100 is then dropped to sandwich mask 222 between it and platen 102 to "iron" it out. The sandwiched mask is then heated by the platens to induce mask expansion.
  • the factory fixture frame 220 is then lowered making contact with the lower heater platen 102. As the lower platen 102 is pushed downward the upper platen follows.
  • the sandwiched mask 222 is now wiped, with consistent uniformity, into grooves 224 of fixture 220 by shoes 232, which shoes are cammed inwardly by the inwardly directed lip 224l of fixture groove 224. This action serves to roll the mask intimately around lip 224l as shoe 232 slides relative to the mask against the resistance posed by drag spring 230. At the same time, the undersides of the shoe shoulders slide across rub pads 255.
  • each of three indexing slots 270 in its outer flange area engage one of three precision guidance spheres 272 which are pneumatically urged upwards.
  • This arrangement assures an accurate alignment of frame 220 with respect to the array since the lateral relationship of the guidance spheres is fixed relative to the locating pins 268 on lower heater platen 102.
  • Cylinders 246 are then energized thus elevating cam 250 to drive cam dwell 250b between rollers 260 to drive scissors arms 248a outward and scissors jaws 254 inward to compress U-spring 228.
  • the shoes 232 are relieved of the high clamping contact with the side walls of groove 224. This contact is achieved through exertion of the heavy U-springs 228 when they are not being compressed by the gripper jaws 254.
  • the mask scrap 226 is now no longer anchored to the factory fixture frame 220 and upon subsequent raising of the frame 220 by the carriage 276, the mask peripheral scrap 226 can be readily removed from machine 96. This condition is shown in Figure 24. It should be noted that during this "extraction” process, the shoes 232 are cammed inwards relative to the U-springs 228 by the frame lips 224l in order that the nose of the shoes can clear the lips.
  • the apparatus 96 is now ready to receive the next mask foil 222 for the tensing-clamping procedure thus, effectively, ending and initiating the aforesaid closed loop process.
  • the left shoe is retracted inward against the left leg of U-spring 228 and immobilized in this position by welding pin 240 to the left leg of spring 228.
  • This side of the spring clip assembly is always deployed to the "outside", or non-mask wiping side of the basic spring clip orientation. This was determined in practice of the invention to be desirable for minimizing adverse frictional forces during automatic insertion of the spring clips into the factory fixture frames.
  • Figure 25 shows a factory fixture frame, generally designated 320, similar to the frame 2 of Figs. 12-24.
  • factory fixture frame 320 includes receptacle means in the form of grooves 324 (Fig. 26) for receiving an edge 326 of shadow mask 322 and within which the mask edge is clamped.
  • Mask tensing-clamping machine 96 receives factory fixture frame 320 which is loaded into the machine by an operator in similar fashion to frame 82 of Fig. 3.
  • the machine also provides for receiving shadow mask 322 in a free state between upper and lower platens 100 and 102, respectively.
  • the platens are heated to provide for expansion of shadow mask 322 as the platens sandwich the mask therebetween. Edges 326 of the shadow mask are clamped into grooves 324 while the shadow mask is heated.
  • a peripheral portion of factory fixture frame 320 is shown with a peripheral groove 324.
  • Shadow mask 322 is illustrated with an edge portion 326 thereof being clamped within a "keystone", or angled sidewall, groove 324 by elongated mechanical mask-retaining means in the form of a tube-like member 328.
  • the tube-member is generally cylindrical and is forced into groove 324 in the direction of arrow "A" to wrap the edge of the shadow mask around the edge of the groove.
  • the tube-like member is of metal or other hard material and is afforded a press-fit retention within groove 324 by virtue of the self-locking angle feature of the groove, thereby sandwiching the edge of the shadow mask between the tube-like member and the sides of the groove. This provides a temporary and removable support of an in-process shadow mask in tension.
  • a series of access holes 327 are arranged to communicate between the bottom of groove 324 and the outside of frame 320 to permit insertion of a comb-like tool in order to extricate tube 328.
  • upper and lower platens 100 and 102 are actuated to sandwich shadow mask 322 therebetween.
  • the platens then are heated to heat the shadow mask and allow the mask to expand. While the shadow mask is still heated, the shadow mask is brought into position generally coplanar with the top of factory fixture frame 320, as seen in Figure 26. While still heated, rod-like member 328 is forced into groove 324 wrapping the edge 326 of shadow mask 322 around the corners of the groove therewith to temporarily and removably support the shadow mask in the groove.
  • the heated platens then are separated and the shadow mask is allowed to cool and shrink in tension while still being temporarily and removably supported on frame 320 by virtue of tube-like member 328 being seated in groove 324.
  • Figure 27 shows a form of the invention somewhat similar to that of Figure 26, but the tube-like member 328a is fabricated of compressible material, such as nylon or like material. This enhances the wrapping and gripping of edge 326 of shadow mask 322 between the side walls of groove 324'. For this embodiment, the walls of groove 324' are not angled or keystoned. It can be seen in Figure 27 that compressible tube-like member 328a has been compressed generally in the direction of arrows "B". Otherwise, the operation is the same as that described in relation to the form of the invention shown in Figure 26 in regard to the sequence of heating the shadow mask and allowing it to cool shrink.
  • the Figure 27 embodiment is also provided with a series of access holes 327' (only one shown) to facilitate removal of tube 328a.
  • Figure 28 shows another form of the invention wherein the tube-like member is identified as 328b and is split, as at 330, lengthwise of the tube to provide compressibility of the tube. This not only enhances the wrapping and clamping capability of the tube similar to that of the compressible tube 328a of Figure 27, but as will be shown, this embodiment of the invention also includes means to facilitate ready removal of the tube.
  • groove 324'' is undercut or enlarged at the base thereof, as at 324''a, such that the base of the groove is wider than the uncompressed diametral dimension of the tube.
  • tube 328b is forced downwardly in the direction of arrow "C" to the position shown in phantom where it is uncompressed and thus substantially loose within undercut portion 324'' of groove 324''.
  • the tube then can be removed simply by sliding the tube lengthwise out of the groove either before or after the edge portion of the shadow mask has been severed.
  • Figures 29a-29f show another form of the invention which embodies a pair of rod-like members 328c and 328d. It also should be noted that the bottom of the groove 324'''c now has a stepped configuration defining a "high" ledge portion 324'''b and a lower base portion 324'''c.
  • Rod 328c is of relatively hard material, such as metal, and rod 328d is of relatively soft compressible material, such as nylon. It additionally should be noted that rod 28c is of a larger diameter than that of rod 328d.
  • edge 326 of shadow mask 322 is brought into the position shown in Figure 29a, with the mask in heated condition and with rods 328c, 328d then being brought to overlay the mask.
  • Figures 29b and 29c show rods 328c, 328d being brought into position to wrap mask edge 326 around the upper rounded corner of groove 324''', in the direction of arrows "D".
  • Figure 29d shows the wrapping of the mask edge completed, with enlarged rod 328c now seated on top of ledge 324'''b.
  • Figure 30 shows a factory fixture frame, generally designated 420 similar to the frame 2 of Figures 12-24.
  • factory fixture frame 420 includes receptacle means in the form of groove or recess means 424 (Fig. 30) for receiving an edge 426 of shadow mask 422 and within which the mask edge is clamped.
  • Mask tensing-clamping machine 96 receives factory fixture frame 420 which is loaded into the machine by an operator in similar fashion to frame 82 of Fig. 3.
  • the machine also provides for receiving shadow mask 422 in a free state between upper and lower platens 100 and 102, respectively.
  • the platens are heated to provide for expansion of shadow mask 422 as the platens sandwich the mask therebetween. Edges 426 of the shadow mask are clamped into a recess means 424 while the shadow mask is heated.
  • Figure 31 shows a fragmented section through a corner of factory fixture frame 420 illustrating one aspect of this further modification of the invention which includes a peripheral recess means in the form of a corner cutout 424a extending longitudinally along the outside of the fixture frame.
  • a spring-loaded elongate means is positionable within cutout 424a to clamp edge 426 of shadow mask 422.
  • spring-loaded elongate means 430 include a rigid rod-like member 432 which is generally cylindrically shaped, which may be in the form of a tube and which complementarily mates within cutout 424a.
  • a leaf spring 434 is secured to the outer periphery of fixture frame 420, as by fastening means 436, whereby the leaf spring is biased against the outside of rod 430, as at 438, in the direction of arrow "A".
  • rod 432 preferably is of a greater diameter than the width of cutout 424a so that the leaf spring is cocked away from the side of the fixture frame when rod 432 is in position for clamping and temporarily and removably supporting an in-process shadow mask in tension.
  • Leaf spring 434 may be elongated along cutout 424a, or a plurality of leaf springs may be spaced along the cutout for engaging rod 432.
  • the shadow mask is brought into generally coplanar position with the top of factory fixture frame 420, as seen in Figure 31, with edges 426 overlying cutout 424a.
  • Rod 432 then is moved in the direction of arrow "B" to wrap mask edge 426 around the corner of cutout 424a through a 180 o wrap angle.
  • Leaf spring 434 is effective to bias rod 432 against the mask edge to clamp the mask edge for temporarily and removably supporting the in-process shadow mask in tension after the shadow mask is allowed to cool and shrink in tension.
  • Figure 32 shows another embodiment of the invention wherein the peripheral recess means 424 is in the form of a groove 424b disposed in an outer peripheral side 440 of factory fixture frame 420. It can be seen that edge 426 of shadow mask 422 is wrapped around the fixture frame through a wrap angle of 360 o and is seated in groove 424b.
  • the mask retaining means comprises a unitary retainer member, generally designated 442, for clamping mask edge 426 in groove 424b to temporarily and removably support the in-process shadow mask in tension.
  • retainer member 442 includes a rigid head portion 444 which is rounded at 446 to complementarily mate with groove 424b to sandwich mask edge 426 between head portion 444 and the interior of the groove.
  • a leaf spring portion 48 extends from head portion 444 and is secured to the side of factory fixture frame by appropriate fastening means 450.
  • a plurality of the retainer members 442 are spaced longitudinally along groove means 424b along each side of the factory fixture frame. The leaf springs are effective to bias head portions 444 into groove 424b in the direction of arrow "C".
  • a tube is inserted in a groove with the resulting clamping force being established by deformation of the clamped tube due to the smaller cross-section of the groove relative to the tube.
  • Such a system inherently is characterized by a high spring rate thus making the clamping force highly sensitive to dimensional variations as could arise from wear or manufacturing tolerances.
  • Relatively low spring rate requires substantial deflection to achieve a required load. As a result, a minor change in deflection due to wear does not significantly affect the magnitude of applied load.
  • An advantage of wrap angle is to spread the clamping force over a larger surface area of the mask foil in order to minimize pinching forces which can cause local damage resulting in failure of the mask material at the clamping location.
  • wrap angle is an exponential term in the force equation, increased wrap angles can result in very significant increases in force ratio.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
  • Electrodes For Cathode-Ray Tubes (AREA)
  • Liquid Crystal (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
  • Electroplating Methods And Accessories (AREA)
  • Prevention Of Electric Corrosion (AREA)
EP88905282A 1987-05-18 1988-05-18 Process and apparatus for the manufacture of cathode ray tubes having tension masks Expired - Lifetime EP0355124B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT88905282T ATE88595T1 (de) 1987-05-18 1988-05-18 Verfahren und vorrichtung zur herstellung von mit gespannten masken versehenen kathodenstrahlroehren.

Applications Claiming Priority (8)

Application Number Priority Date Filing Date Title
US140019 1980-04-14
US07/051,896 US4790786A (en) 1987-05-18 1987-05-18 Factory fixture frame for an in-process tension mask color cathode ray tube
US51896 1987-05-18
US139892 1987-12-31
US07/139,892 US4894037A (en) 1987-12-31 1987-12-31 Factory fixture frame with means for temporarily and removably supporting an in-process tension mask for a color cathode ray tube
US07/140,019 US4934974A (en) 1987-12-31 1987-12-31 Factory fixture frame with means for temporarily and removably supporting an in-process tension mask for a color cathode ray tube
US07/139,997 US4840596A (en) 1987-12-31 1987-12-31 Factory fixture frame with means for temporarily and removably supporting an in-process tension mask for a color cathode ray tube
US139997 1987-12-31

Publications (2)

Publication Number Publication Date
EP0355124A1 EP0355124A1 (en) 1990-02-28
EP0355124B1 true EP0355124B1 (en) 1993-04-21

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EP88905282A Expired - Lifetime EP0355124B1 (en) 1987-05-18 1988-05-18 Process and apparatus for the manufacture of cathode ray tubes having tension masks

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EP (1) EP0355124B1 (no)
JP (1) JPH02503610A (no)
KR (1) KR890702230A (no)
AT (1) ATE88595T1 (no)
BR (1) BR8807510A (no)
CA (1) CA1316977C (no)
DE (1) DE3880485T2 (no)
HK (1) HK94193A (no)
NO (1) NO890202L (no)
WO (1) WO1988009561A1 (no)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TW385913U (en) * 1996-05-15 2000-03-21 Matsushita Electronics Corp Planar member for shadow mask of cathode-ray tube and manufacturing method of shadow mask
TW460893B (en) * 1998-11-27 2001-10-21 Koninkl Philips Electronics Nv Color selection means for color display tubes and color display tubes provided with the same

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3894321A (en) * 1974-01-24 1975-07-15 Zenith Radio Corp Method for processing a color cathode ray tube having a thin foil mask sealed directly to the bulb

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2733366A (en) * 1956-01-31 Grimm ctal
NL158008B (nl) * 1950-04-28 Ibm Holografisch geheugen.
US4591344A (en) * 1983-09-30 1986-05-27 Zenith Electronics Corporation Method of fabricating a tension mask color cathode ray tube

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3894321A (en) * 1974-01-24 1975-07-15 Zenith Radio Corp Method for processing a color cathode ray tube having a thin foil mask sealed directly to the bulb

Also Published As

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NO890202D0 (no) 1989-01-17
NO890202L (no) 1989-01-17
DE3880485T2 (de) 1993-11-04
ATE88595T1 (de) 1993-05-15
CA1316977C (en) 1993-04-27
HK94193A (en) 1993-09-17
KR890702230A (ko) 1989-12-23
EP0355124A1 (en) 1990-02-28
JPH02503610A (ja) 1990-10-25
DE3880485D1 (de) 1993-05-27
BR8807510A (pt) 1990-04-17
WO1988009561A1 (en) 1988-12-01

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