US3862448A - Colour picture tube including shadow mask having self-compensation function for thermal stress - Google Patents

Colour picture tube including shadow mask having self-compensation function for thermal stress Download PDF

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Publication number
US3862448A
US3862448A US285322A US28532272A US3862448A US 3862448 A US3862448 A US 3862448A US 285322 A US285322 A US 285322A US 28532272 A US28532272 A US 28532272A US 3862448 A US3862448 A US 3862448A
Authority
US
United States
Prior art keywords
shadow mask
thermal stress
picture tube
peripheral portion
side portion
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
US285322A
Other languages
English (en)
Inventor
Tomio Ishizuka
Hiromi Kanai
Takao Kawamura
Kenichi Fukuzawa
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.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
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 JP7936571U external-priority patent/JPS4835267U/ja
Priority claimed from JP10085271U external-priority patent/JPS5552610Y2/ja
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Application granted granted Critical
Publication of US3862448A publication Critical patent/US3862448A/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
    • 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
    • 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
    • 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

  • ABSTRACT The peripheral portion of a shadow mask which is spot welded to a supporting frame is provided with a plurality of openings so as to form a cushion zone for absorbing and minimizing the stress created therein by heat,
  • the shadow mask assembly comprises a shadow mask with a plurality of small perforations and a supporting frame welded to the periphery of the shadow mask and the shadow mask assembly is supported in an evacuated envelope of the colour picture tube through a plurality of leaf springs.
  • the supporting frame is welded to the periphery of the shadow mask with a suitable spacing therebetween.
  • the shadow mask is made of an extremely thin metal sheet having a thickness of about 0.2mm which is provided with a plurality of small perforations, maldistribution of a small stress will cause deformation of the shadow mask.
  • the central portion of the shadow mask is provided with a plurality of small perforations whereas the peripheral portion is not perforated so that these two portions have different mechanical strength with the result that the heat expansion of the shadow mask caused by the collision of the electron beams will cause abnormal deformation of the interface between the central and the peripheral portions.
  • Such a deformation is enhanced by the facts that the peripheral portion is secured to the frame having a large heat capacity and that the electron beams are shielded by the mask frame and an electron shield secured thereto.
  • a further object of this invention is to provide a colour picture tube including an improved colour selection electrode which is constructed to prevent abnormal local deformation caused by thermal expansion of the colour selectionelectrode.
  • a colour picture tube comprising a colour selection electrode assembly including an operating portion adapted to transmit an electron beam, a peripheral portion surrounding the operating portion, and a supporting frame welded to the peripheral portion, characterized in that a cushion zone is provided for the peripheral portion for absorbing and alleviating the stress created therein due to heat.
  • the cushion zone is formed by providing a plurality of small perforations, blind openings or grooves in the peripheral portion or decreasing the thickness thereof.
  • FIG. 1 is a perspective view of a shadow mask assem bly embodying the invention and FIGS. 2 and 3 show partial sectional views of modified shadow masks.
  • the peripheral side 24 is provided with cushion zones 26 formed with small perforations 25. While in the illustrated example small perforations are formed throughout the entire surface of the peripheral side 24, it should be understood that such perforations may be formed in areas around equally spaced apart spot welds which interconnect the side 24 to a supporting frame 30.
  • Cushion zones 26 with small perforations absorb or alleviate the stress formed in the shadow mask 20 and I or frame 30. Consequently, the shadow mask 20 is prevented from being deformed by the thermal stress created therein by the heat generated by the high temperature treatment carried out during the fabrication of the colour picture tube or generated during normal use thereof, thereby displaying a picture image of excellent quality without any degradation of the colour purity.
  • the result of experiment shows that in a shadow mask of thin metal sheet having a thickness of about 0.15mm wherein the central portion thereof is provided with a plurality of small perforations at a pitch of about 0.50, 0.60 or 0.70mm, a diameter of from 0.15 to 0.45mm of the small perforations 25 in the cushion zones 26 and a density of from 10 to of the perforations 25 give satisfactory results.
  • the configuration and size of the small perforations 25 in the cushion zones 26 may be decided properly in design in accordance with the number of spot welds and the like.
  • the small perforations are adapted merely to form cushion zones 26 for stress acting between the operating portion 22 of the shadow mask 20 having perforations 21 and the spot-welded portions of the peripheral side 24. From the standpoint of manufacturing it is advantageous to make equal the diameters of the perforations 21 in the I operating portion 22 and the perforations 25 in the side 24.
  • a cushion zone 26 is formed in both'peripheral portion 23 and the peripheral side 24 of the shadow mask 20.
  • the cushion zone is provided with a plurality of small blind openings 28, preferably having the same diameter as the perforations 21 at the central portion 22. Provision of a plurality of small blind openings 28 decreases the effective thickness of the peripheral portion 23 and the side 24, thus assuring substantially uniform mechanical strength over the entire area of the shadow mask.
  • the shadow mask 20 expands in the direction of the passage 40 of the electron beam as shown by dotted lines. For this reason, the shadow mask 20, especially the central portion thereof is freed from any abnormal deformation caused by thermal expansion thereby preventing the degradation of the colour purity and colour shading of the colour picture tube.
  • numeral 42 indicates a panel of the envelope of the tube.
  • the thickness of the pheripheral portion 23 and the side of a shadow mask is decreased to form a cushion zone which has the same effect as the embodiment shown in FIG. 2.
  • the dot and dash lines show the original thickness of the cushion zone.
  • the cushion zone 26 is formed by providing a plurality of small blind holes or by decreasing the thickness of the cushion zone, grooves may be provided for this zone provided that the uniform mechanical strength of the shadow mask can be assured.
  • FIGS. 2 and 3 show one example where the outer side (so-called panel side) of the shadow mask is cut away, it should be understood that the invention is also applicable to formation of the cushion zones by eliminating the inner side of the shadow mask.
  • a color picture tube comprising a colour selection electrode assembly including an integrally formed operating portion adapted to transmit an electron beam, a peripheral portion surrounding said operating portion and a side portion; and a supporting frame welded to said side portion, the improvement which comprises a cushion zone formed by weakening the mechanical strength continuously over the area of thermal stress transmission in said peripheral portion and said side portion through provision of a uniformly distributed plurality of small blind openings over said area to obviate maldistribution of thermal stress in the mask.
  • a color picture tube comprising a colour selection electrode assembly including an integrally formed operating portion adapted to transmit an electron beam, a peripheral portion surrounding said operating portion and a side portion; and a supporting frame welded to said side portion.
  • the improvement which comprises a cushion zone formed by weakening the mechanical strength continuously over the area of thermal stress transmission in said peripheral portion and said side portion through provision of a reduced thickness over said area to obviate maldistribution of thermal stress in the mask.

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  • Electrodes For Cathode-Ray Tubes (AREA)
US285322A 1971-09-03 1972-08-31 Colour picture tube including shadow mask having self-compensation function for thermal stress Expired - Lifetime US3862448A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP7936571U JPS4835267U (de) 1971-09-03 1971-09-03
JP10085271U JPS5552610Y2 (de) 1971-11-01 1971-11-01

Publications (1)

Publication Number Publication Date
US3862448A true US3862448A (en) 1975-01-21

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
US285322A Expired - Lifetime US3862448A (en) 1971-09-03 1972-08-31 Colour picture tube including shadow mask having self-compensation function for thermal stress

Country Status (4)

Country Link
US (1) US3862448A (de)
DE (1) DE2242782B2 (de)
FR (1) FR2151051B1 (de)
GB (1) GB1407608A (de)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4045701A (en) * 1976-02-02 1977-08-30 Zenith Radio Corporation Shadow mask supported by cathode ray tube faceplate
US4099086A (en) * 1975-11-06 1978-07-04 Licentia Patent-Verwaltungs-G.M.B.H. Aperture mask unit for color television picture tube
US4191909A (en) * 1978-10-23 1980-03-04 Zenith Radio Corporation Color CRT with shadow mask having peripherally grooved skirt
DE3517401A1 (de) * 1984-05-15 1985-11-21 Rca Corp., New York, N.Y. Farbbildroehre, die einen schattenmaskenrahmen mit abgestumpften ecken hat
DE3601662A1 (de) * 1985-01-22 1986-07-24 Rca Corp., Princeton, N.J. Farbbildroehre mit verbesserter schattenmaske
US4767962A (en) * 1986-07-02 1988-08-30 Zenith Electronics Corporation Color cathode ray tube and tensible shadow mask blank for use therein
US4859901A (en) * 1981-10-29 1989-08-22 U.S. Philips Corporation Color CRT shadow mask with wrinkle-free corners
US6043595A (en) * 1996-11-11 2000-03-28 Kabushiki Kaisha Toshiba Shadow mask having a curved surface with compressed, strengthening dents
US6111346A (en) * 1997-03-11 2000-08-29 Hitachi, Ltd. Color cathode ray tube having shadow mask structure with curl reduced in skirt portion
US6255765B1 (en) 1998-04-24 2001-07-03 Hitachi, Ltd. Color cathode ray tube having a shadow mask structure with curl reduced in a skirt portion thereof
WO2004019365A2 (en) * 2002-08-14 2004-03-04 Lg. Philips Displays Color display tube with improved color selection electrode
EP1432003A1 (de) * 2002-12-20 2004-06-23 Thomson Licensing S.A. Kathodenstrahlröhre mit Schattenmaske mit teilgeätztem Maskenrand und Rahmenbereich

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3018623C2 (de) * 1980-05-16 1983-03-24 Kernforschungsanlage Jülich GmbH, 5170 Jülich Beschleunigungsgitter
US4748371A (en) * 1987-02-10 1988-05-31 Rca Licensing Corporation Cathode-ray tube shadow mask for low overscan
CN1165945C (zh) * 1997-03-14 2004-09-08 株式会社东芝 彩色阴极射线管
KR100224981B1 (ko) * 1997-07-23 1999-10-15 구자홍 평면브라운관의 새도우마스크 구조체
JP2001110331A (ja) 1999-10-08 2001-04-20 Hitachi Ltd カラー陰極線管
US6710527B2 (en) * 2000-08-04 2004-03-23 Matsushita Electric Industrial Co., Ltd. Cathode ray tube with slit in dead space of shadow mask

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2733366A (en) * 1956-01-31 Grimm ctal
US2795718A (en) * 1954-08-18 1957-06-11 Rca Corp Color kinescopes
US3524974A (en) * 1968-08-13 1970-08-18 Sylvania Electric Prod Shadow mask supporting structure having thermal expansion correction means
US3585431A (en) * 1970-06-15 1971-06-15 Rca Corp Shadow-mask cathode-ray tube including a masking member comprising a skirt having indentations and projections overlapping and attached to a frame
US3639799A (en) * 1969-04-02 1972-02-01 Tubal Ind Inc Shadow mask with reinforcing ring for colored television picture tube
US3660708A (en) * 1969-03-19 1972-05-02 Matsushita Electronics Corp Shadow mask support means for a color television image tube
US3809945A (en) * 1973-03-02 1974-05-07 Zenith Radio Corp Shadow mask for color cathode ray tube and method of manufacture thereof

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2733366A (en) * 1956-01-31 Grimm ctal
US2795718A (en) * 1954-08-18 1957-06-11 Rca Corp Color kinescopes
US3524974A (en) * 1968-08-13 1970-08-18 Sylvania Electric Prod Shadow mask supporting structure having thermal expansion correction means
US3660708A (en) * 1969-03-19 1972-05-02 Matsushita Electronics Corp Shadow mask support means for a color television image tube
US3639799A (en) * 1969-04-02 1972-02-01 Tubal Ind Inc Shadow mask with reinforcing ring for colored television picture tube
US3585431A (en) * 1970-06-15 1971-06-15 Rca Corp Shadow-mask cathode-ray tube including a masking member comprising a skirt having indentations and projections overlapping and attached to a frame
US3809945A (en) * 1973-03-02 1974-05-07 Zenith Radio Corp Shadow mask for color cathode ray tube and method of manufacture thereof

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4099086A (en) * 1975-11-06 1978-07-04 Licentia Patent-Verwaltungs-G.M.B.H. Aperture mask unit for color television picture tube
US4045701A (en) * 1976-02-02 1977-08-30 Zenith Radio Corporation Shadow mask supported by cathode ray tube faceplate
US4191909A (en) * 1978-10-23 1980-03-04 Zenith Radio Corporation Color CRT with shadow mask having peripherally grooved skirt
US4859901A (en) * 1981-10-29 1989-08-22 U.S. Philips Corporation Color CRT shadow mask with wrinkle-free corners
DE3517401A1 (de) * 1984-05-15 1985-11-21 Rca Corp., New York, N.Y. Farbbildroehre, die einen schattenmaskenrahmen mit abgestumpften ecken hat
US4599533A (en) * 1984-05-15 1986-07-08 Rca Corporation Color picture tube having shadow mask frame with truncated corners
DE3601662A1 (de) * 1985-01-22 1986-07-24 Rca Corp., Princeton, N.J. Farbbildroehre mit verbesserter schattenmaske
US4767962A (en) * 1986-07-02 1988-08-30 Zenith Electronics Corporation Color cathode ray tube and tensible shadow mask blank for use therein
US6043595A (en) * 1996-11-11 2000-03-28 Kabushiki Kaisha Toshiba Shadow mask having a curved surface with compressed, strengthening dents
US6111346A (en) * 1997-03-11 2000-08-29 Hitachi, Ltd. Color cathode ray tube having shadow mask structure with curl reduced in skirt portion
US6274974B1 (en) 1997-03-11 2001-08-14 Hitachi, Ltd. Color cathode ray tube having an improved shadow mask structure
US6437497B2 (en) 1997-03-11 2002-08-20 Hitachi, Ltd. Color cathode ray tube having an improved shadow mask
US6255765B1 (en) 1998-04-24 2001-07-03 Hitachi, Ltd. Color cathode ray tube having a shadow mask structure with curl reduced in a skirt portion thereof
US6465942B2 (en) 1998-04-24 2002-10-15 Hitachi, Ltd. Color cathode ray having a shadow mask structure with curl reduced in a skirt portion thereof
WO2004019365A2 (en) * 2002-08-14 2004-03-04 Lg. Philips Displays Color display tube with improved color selection electrode
WO2004019365A3 (en) * 2002-08-14 2005-04-07 Lg Philips Displays Color display tube with improved color selection electrode
EP1432003A1 (de) * 2002-12-20 2004-06-23 Thomson Licensing S.A. Kathodenstrahlröhre mit Schattenmaske mit teilgeätztem Maskenrand und Rahmenbereich

Also Published As

Publication number Publication date
GB1407608A (en) 1975-09-24
FR2151051B1 (de) 1974-10-25
DE2242782B2 (de) 1976-04-29
FR2151051A1 (de) 1973-04-13
DE2242782A1 (de) 1973-03-08

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