US3639799A - Shadow mask with reinforcing ring for colored television picture tube - Google Patents

Shadow mask with reinforcing ring for colored television picture tube Download PDF

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Publication number
US3639799A
US3639799A US822792A US3639799DA US3639799A US 3639799 A US3639799 A US 3639799A US 822792 A US822792 A US 822792A US 3639799D A US3639799D A US 3639799DA US 3639799 A US3639799 A US 3639799A
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US
United States
Prior art keywords
wall
metal sheet
set forth
flange
mask
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
US822792A
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English (en)
Inventor
Myron C Kirchner
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Tubal Ind Inc
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Tubal Ind Inc
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Publication date
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Publication of US3639799A publication Critical patent/US3639799A/en
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    • 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
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/14—Manufacture of electrodes or electrode systems of non-emitting electrodes
    • H01J9/142—Manufacture of electrodes or electrode systems of non-emitting electrodes of shadow-masks for colour television tubes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/07—Shadow masks
    • H01J2229/0722—Frame
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/07—Shadow masks
    • H01J2229/0727—Aperture plate
    • H01J2229/0766—Details of skirt or border
    • H01J2229/0772—Apertures, cut-outs, depressions, or the like

Definitions

  • a shadow mask for color TV picture tubes contains the con; ventional foraminous or translucent area formed by a multiple [52] U.S.Cl ..3l3/85 of miniature apertures in a curved portion of a thin metal 5
  • the conventional shadow mask contains the curved translucent area formed by a, multitude of miniature apertures through a metal sheet surrounded by an imperforate section or portion of the same metal sheet.
  • the practice heretofore has been to attach the mask to amounting ring to form an assembly and then the entire assembly is mounted in some convenient fashion onto the glass bulb.
  • the primary function of the mounting ring is tostabilize the mask. But it and its associated hardware became a substantial portion of the mass of the mask assembly. This technique not only makes the mask assembly costly and quite heavy, but also, because of the mass involved, there is usually produced a fairly large temperature gradient in the assembly before it is able to reach a uniform ambient temperature level. This usually requires a considerable amount of operational time.
  • the present invention which is sometimes referred to as a uniframe mask, is somewhat of a variation and modification of the aperture mask described in the aforementioned patent. It contains the conventional curved translucent area surrounded by an imperforate section which bends back to form a rearwardly extending wall and terminating with an inward extending flange from the rear edge of the wall.
  • a circumambient groove around the translucent area provides a first strengthening rib and a continuous groove in the wall section provides additional strengthening. Further strengthening can be provided by cross ribs in the wall section which may be extended onto the flange area.
  • a metal ring or annulus is rigidly attached to the flange area for reinforcement.
  • FIG. l is a rear view of the shadow mask for a colored TV picture tube constructed according to the teachings of the invention.
  • FIG. 2 is a view of the shadow mask from the front
  • FIG. 3 is a sectional view taken along viewing line of 3-3 of FIG. I;
  • FIG. 4 is a side elevational view of an embodiment of the invention.
  • FIG. 5 is a sectional view takenalong viewing line 5-5 of FIG. 4.
  • the shadow mask of the present invention may be of any form suitable for use in picture tube assemblies, the most general forms being rectangular or circular. Since the former is most popular today, the invention will be described as used in producing a rectangular shadow mask.
  • the mask contains the conventionalforaminous or translucent area 10 formed by a myriad of miniature apertures which are usually chemically milled through a thin sheet of metal, such as stainless steel.
  • a thin sheet of metal such as stainless steel.
  • the shadow mask is located near the front viewing face of the picture tube between it and the electron guns.
  • the electron beams are suitably directed through the translucent area of the mask to impinge upon the colored phosphor dots on the inside of the face of the picture tube.
  • the mask is also used during the process for laying down the color phosphor dots in the conventional triad pattern.
  • the mask ordinarily must be removed and repositioned with respect to the face of the picture tube a number of times so it is apparent that stability is critical to make sure that the tiny apertures return to virtually their exact previous location each time the mask is temporarily removed and replaced. It is also apparent that temperature stability is quite critical so that the translucent area does not shift and interfere with the passage of the electron beams as they travel from the guns to impinge upon the respective color phosphor dots.
  • the translucent area 10 is partially domed or curved, usually aspherically, to conform to the curved inner face of the picture tube.
  • methods, procedures and equipment have been developed and are today widely known and used throughout the color TV industry for etching out the translucent area 'and for curving or shaping the mask face to the desired contour. These methods, procedures and equipment are not considered part of the present invention.
  • a marginal imperforate area 11 which is merely a continuation of the same metal sheet but which has not been etched through.
  • area 11 near the outer edge of the translucent area 10, there is a continuous, inward-projecting, shallow groove 12 which serves as a strengthening rib for the face area of the aperture mask.
  • This rib is formed in a press using standard techniques.
  • the metal bends backward at about a angle, with respect to a planar projection of the mask face to form a rearward extending wall section 13 which, similar to the marginal section 11, is preferably a further continuation of the same metal sheet.
  • the depth of draw to form wall 13 may vary from mask to mask depending on the size and type of mask being formed.
  • the wall 13 may be in the order of 1% inches deep for an aperture mask used in a 21 or 24 inch picture tube.
  • Wall 13 contains a continuous groove or strengthening rib which strengthens the wall section. Selection of the location and size of rib 14 in wall 13 depends on a number of factors, including the size of the mask, the depth of the wall, the metal thickness, etc. The choice can and must be made by the skilled artisan for each application and no definite formula to cover all applications appears to be reasonably determinable. Investigations have shown that in some instances additional ribs, similar to rib 14, may be formed in the wall 13 to provide some additional strength.
  • flange 16 which is approximately at a 90 angle to the wall 13.
  • Flange 16 completely encircles the opening at the rear of the mask.
  • a metal reinforcing ring 17 Overlaying flange 16 and rigidly attached thereto, such as by welding, is a metal reinforcing ring 17.
  • ring 17 is made out of the same metal as the mask. It may be the same thickness as the metal sheet from which the mask is formed but for the most part, it has been found preferable that the ring metal be somewhat thicker, and a thickness in the order of twice that of the flange has worked very satisfactorily.
  • the inner edge 18 of ring 17 can be flared partially upward for shielding. in addition, as shown in the FIG.
  • the ring 17 may extend out beyond wall 13 for further shielding to prevent leakage of light and reflection around the outside of the mask between the glass bulb and the mask assembly. It has been found that ring 17 welded to the flange l6 reinforces the mask to such a degree that the stability and strength is many times that of the mask without the ring.
  • ribs 20 are substantially equally spaced along wall 13, are parallel to one another and extend rearward from rib 14 down to the end of the wall section and further extend at least part way down flange 16.
  • this arrangement may be preferable, it is contemplated and has been shown that variations thereof may and will produce substantial additional supporting strength and so should be considered to come within the spirit and scope of this invention.
  • the ribs 20 may not be parallel to one another and/or may be at other than a right angle to rib 14.
  • the number of ribs 20 and the dimensions of the grooves is a matter of design or choice depending upon many factors such as the dimension and shape of the mask. The practicing artisan can make this choice based upon his experience and knowledge. Another factor which must be taken into account when determining the size and location of the supporting cross ribs 20, as well as the continuous rib 14, is that these ribs should not interfere with the mounting pads or springs (not shown) which are normally attached to the wall 14 for the finished mask to the glass bulb.
  • a fiat metal sheet called a blank, which contains the translucent area formed by chemically milling out the tiny apertures, is annealed to reduce its hardness, to improve its machinability, to facilitate cold working, to produce a desired microstructure and to obtain desired mechanical, physical or other properties.
  • the metal blank is subjected to roller-leveling which is a process whereby the blank is sent over and through a series of rollers which break down the molecular structure so that the metal blank can later be drawn down and formed without distorting or otherwise damaging the miniature apertures.
  • the blank is next placed in a press where the face of the mask is drawn down to the desired curvature. All of the steps listed heretofore are commonplace and have been used in the industry for a considerable period of time and so are not considered a novel part of the present invention. Yet they are necessary steps in the fabrication of masks constructed according to the teachings of the present invention.
  • Rib 12 may be located immediately adjacent the outer edge of the translucent area 10 or may be located adjacent the corner where wall section 13 meets margin area 11 or anywhere between. This is a choice which may differ with mask shape, size and other factors.
  • the mask then goes through a second press operation to form wall 13. This merely involves drawing down the metal at the correct angle, about while the face area is held firmly in place. An added feature of rib 12 appears during this process step.
  • the draw-down of the wall portion may be a single step operation or may be accomplished by a series of press operations. This is a matter of choice and design depending on many factors and is determinable by those skilled in press operations and techniques.
  • rib 14 is formed in sidewall 13 and the rear end wall 13 is tucked inward at about a 90 angle to form flange 16.
  • ring 17 is placed over flange l6 and welded thereto.
  • ring 17 is previously cut to size and is located and'held over the flange in a suitable fixture and a number of welding guns are strategically located to weld the ring onto the flange.
  • ring 17 has been found to provide suitable reinforcement when it is the same thickness as the metal sheet from which the rest of the mask is made. In those cases the ring 17 can be cut from what otherwise would be scrap metal leftover from the unused portion of the metal sheet. But for the most part, even though ring 17 is made from 'the same metal it is necessary to have it a thicker gauge to provide the necessary degree of stability.
  • a reinforced shadow mask for a colored television picture tube comprising: a thin metal sheet having a front section containing a curved translucent area defined by a myriad of miniature apertures through the metal sheet, an imperforate margin area around the translucent area, a further imperforate section bent back from the margin area at about 90 to form a rearwardly directed wall, said wall containing a continuous strengthening rib, the other end of the wall section being bent to form an inwardly directed flange; and a planar metal reinforcing ring rigidly attached to said flange with the ring in surface to surface contact with the flange.
  • the invention as set forth in claim 1 further including a plurality of shallow grooves in said wall extending in a direction across said continuous rib, said grooves forming strengthening cross ribs.
  • annulus is characterized by being thicker than the metal sheet and forms a thermally stable combination with the metal sheet.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Electrodes For Cathode-Ray Tubes (AREA)
US822792A 1969-04-02 1969-04-02 Shadow mask with reinforcing ring for colored television picture tube Expired - Lifetime US3639799A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US82279269A 1969-04-02 1969-04-02

Publications (1)

Publication Number Publication Date
US3639799A true US3639799A (en) 1972-02-01

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Family Applications (1)

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US822792A Expired - Lifetime US3639799A (en) 1969-04-02 1969-04-02 Shadow mask with reinforcing ring for colored television picture tube

Country Status (7)

Country Link
US (1) US3639799A (enrdf_load_stackoverflow)
JP (1) JPS4923619B1 (enrdf_load_stackoverflow)
BE (1) BE748376A (enrdf_load_stackoverflow)
DE (1) DE1947433A1 (enrdf_load_stackoverflow)
FR (1) FR2042025A5 (enrdf_load_stackoverflow)
GB (1) GB1230891A (enrdf_load_stackoverflow)
NL (1) NL7004423A (enrdf_load_stackoverflow)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3862448A (en) * 1971-09-03 1975-01-21 Hitachi Ltd Colour picture tube including shadow mask having self-compensation function for thermal stress
US3942064A (en) * 1974-11-14 1976-03-02 Westinghouse Electric Corporation Reinforcing ring structure for a shadow mask
US4092651A (en) * 1975-08-27 1978-05-30 International Standard Electric Corporation Device and method for exposing phosphor dots in a color television picture tube
US4100451A (en) * 1974-08-19 1978-07-11 Zenith Radio Corporation Face panel assembly for a color cathode ray tube
US4308485A (en) * 1978-03-13 1981-12-29 Videocolor, S. A. Shadow mask support in a color cathode ray tube
US4783614A (en) * 1986-10-28 1988-11-08 Zenith Electronics Corporation L-shaped support structure for tensioned shadow mask
SG82533A1 (en) * 1993-11-03 2001-08-21 Rca Thomson Licensing Corp Color picture tube with shadow mask having skirt with reverse bend

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2713765A1 (de) * 1977-03-29 1978-10-12 Licentia Gmbh Farbwahlmaskenanordnung fuer eine farbbildkathodenstrahlroehre
GB2240659A (en) * 1990-01-31 1991-08-07 Samsung Electronic Devices Shadow mask assembly
KR920001571Y1 (ko) * 1989-11-02 1992-03-05 삼성전관 주식회사 음극선관용 섀도우마스크
US5189334A (en) * 1989-11-02 1993-02-23 Samsung Electronic Devices Co., Ltd. Cathode ray tube having shadow mask

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2897392A (en) * 1956-02-09 1959-07-28 Zenith Radio Corp Color television tube mask and frame assembly
US3349272A (en) * 1965-12-16 1967-10-24 Philips Corp Color television tube with shadow mask provided with electron shielding plate coated with heat radiating material
US3351996A (en) * 1965-03-29 1967-11-14 Rauland Corp Method of making a rectangular-mask assembly for a shadow-mask type of color tube
US3376451A (en) * 1966-09-12 1968-04-02 Buckbee Mears Co Shadow mask and magnetic shield unitary construction for color tv picture tubes
US3479546A (en) * 1968-06-11 1969-11-18 Buckbee Mears Co Self-supporting shadow mask for colored tv picture tubes

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2897392A (en) * 1956-02-09 1959-07-28 Zenith Radio Corp Color television tube mask and frame assembly
US3351996A (en) * 1965-03-29 1967-11-14 Rauland Corp Method of making a rectangular-mask assembly for a shadow-mask type of color tube
US3349272A (en) * 1965-12-16 1967-10-24 Philips Corp Color television tube with shadow mask provided with electron shielding plate coated with heat radiating material
US3376451A (en) * 1966-09-12 1968-04-02 Buckbee Mears Co Shadow mask and magnetic shield unitary construction for color tv picture tubes
US3479546A (en) * 1968-06-11 1969-11-18 Buckbee Mears Co Self-supporting shadow mask for colored tv picture tubes

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3862448A (en) * 1971-09-03 1975-01-21 Hitachi Ltd Colour picture tube including shadow mask having self-compensation function for thermal stress
US4100451A (en) * 1974-08-19 1978-07-11 Zenith Radio Corporation Face panel assembly for a color cathode ray tube
US3942064A (en) * 1974-11-14 1976-03-02 Westinghouse Electric Corporation Reinforcing ring structure for a shadow mask
US4092651A (en) * 1975-08-27 1978-05-30 International Standard Electric Corporation Device and method for exposing phosphor dots in a color television picture tube
US4308485A (en) * 1978-03-13 1981-12-29 Videocolor, S. A. Shadow mask support in a color cathode ray tube
US4783614A (en) * 1986-10-28 1988-11-08 Zenith Electronics Corporation L-shaped support structure for tensioned shadow mask
SG82533A1 (en) * 1993-11-03 2001-08-21 Rca Thomson Licensing Corp Color picture tube with shadow mask having skirt with reverse bend

Also Published As

Publication number Publication date
BE748376A (fr) 1970-09-16
GB1230891A (enrdf_load_stackoverflow) 1971-05-05
FR2042025A5 (enrdf_load_stackoverflow) 1971-02-05
DE1947433A1 (de) 1970-10-29
NL7004423A (enrdf_load_stackoverflow) 1970-10-06
JPS4923619B1 (enrdf_load_stackoverflow) 1974-06-17

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