US2906904A - Cathode ray tube - Google Patents

Cathode ray tube Download PDF

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Publication number
US2906904A
US2906904A US578624A US57862456A US2906904A US 2906904 A US2906904 A US 2906904A US 578624 A US578624 A US 578624A US 57862456 A US57862456 A US 57862456A US 2906904 A US2906904 A US 2906904A
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US
United States
Prior art keywords
electron beam
shadow mask
cathode ray
ray tube
beam shield
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
US578624A
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English (en)
Inventor
Earl R Woughter
William J Knochel
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.)
Westinghouse Electric Corp
Original Assignee
Westinghouse Electric Corp
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 to NL216226D priority Critical patent/NL216226A/xx
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US578624A priority patent/US2906904A/en
Priority to GB12245/57A priority patent/GB813954A/en
Priority to FR1171257D priority patent/FR1171257A/fr
Application granted granted Critical
Publication of US2906904A publication Critical patent/US2906904A/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
    • H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
    • H01J29/18—Luminescent screens
    • H01J29/24—Supports for luminescent material
    • 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

  • This invention relates to cathode ray tubes and, more particularly, to electron beam shields for use in cathode ray tubes.
  • the luminescent screen is comprised of a plurality of groups of phosphor dots which emit different colors, e.g., red, green, and blue when they are excited by the impinging electrons.
  • the electrons are emitted by an electron beam generating means, such as an electron gun or plurality of electron guns and are deflected by suitable deflecting means, e.g. magnetic fields supplied by coils external to the tube, in order to scan a suitable pattern.
  • suitable deflecting means e.g. magnetic fields supplied by coils external to the tube.
  • the electrons After the electrons are deflected, they travel in straight lines through a relatively field free region, pass through apertures in a shadow mask electrode and finally strike a phosphor dot which will emit the desired color.
  • the apertures of the shadow mask electrode are in registration with the corresponding phosphor dot groups.
  • an electron beam intended to excite for example, red phosphor dots hit only these dots and that no other electrons arise within the tube which can strike and excite unwanted colors.
  • the alignment and registration of the electron beam source which is considered to include the deflecting means, the shadow mask apertures and the phosphor dots is, therefore, very critical 'and must be accurately done.
  • stray electrons may be generated .within the cathode ray tube due to various causes.
  • One cause of stray electrons is-scattering when the primary electron beam hits the side walls of the envelope of the cathode ray tube at the extremities ofthe scanning pattern. Unless these scattered electrons are prevented from doing so, they may pass between the edge of the shadow mask electrode and the envelope wall and possibly after further scattering, collisions with the mask and the envelope wall, may excite the several phosphor colors of the luminescent screen more or less equally. sults in an array of the generally whitish illumination which strongly desaturates colors and degrades contrast.
  • the rectangular scanning pattern may cause many This re- 2,906,904 Patented Sept. 29, 1959 ice envelope wall itself since the lateral positioning of the shadow mask electrode must be established by the various glass and metal positioning and locating means described in the above-mentioned copending Knochel application, which lateral positioning is done independently of the location and shape of the shadow mask rim and cathode ray tube envolpe wall.
  • FIG. 1 is a perspective view, partly in section, of a cathode ray tube embodying our invention
  • Fig. 2 is a plan view of the inside of the faceplate portion
  • Fig. 3 is a sectional view of a detail portion of one embodiment of our invention.
  • Fig. 4 is a perspective view of a detail portion of another embodiment of our invention.
  • Fig. 5 is a sectional view of a detail portion of Fig. 4 as seen from the rear;
  • Fig. 6 is a detail view of a portion of Fig. 5, and
  • Fig. 7 is a plan view (of a detail portion) of another embodiment of our invention.
  • a cathode ray tube embodying our invention including an envelope member 11 which includes a face panel portion 13 and a funnel portion 19.
  • the face panel portion .13 includes a faceplate portion 15 and a skirt portion 17.
  • the funnel portion 19 includes a flared portion 21 and a neck portion 23.
  • a luminescent screen 25 has been deposited upon the faceplate portion 15.
  • Electron beam generating means 27 have been positioned in the neck portion 23 and generate electron beams 29, which, after traveling through shadow mask electrode apertures 33 of a shodaw mask electrode 31, impinge on the luminescent screen 25 which is comprised of a number of phosphor dots 35. For simplicity, only one aperture 33 and a few dots 35 of the screen 25 are shown.
  • a conductive coating 39 has been applied to'the interior of the envelope member 11 and the face panel portion 13 has been sealed to the funnel portion 19 at a seal portion 41.
  • An electron beam shield member 37 which will be more fully described below,
  • This electron beam shield member 37 intercepts undesirable scattered electrons which may arise, for example, when electron beam 29 strikes the envelope wall and which would create undesirable edge effects, and impurity of color if they were allowed to strikethe luminescent screen 25.
  • This electron beam. shield 37 also eliminates the possibility of an are forming between the luminescent screen 25 and the seal portion 41 during the electric seal 3 process described in *the Knochel "application "entitled Color Television Tube referred to previously.
  • Fig. 2 shows a plan view of the inside of the face panel portion 13 with the shadow mask electrode 31 in position and showing the skirt portion 17.
  • the electron beam shield member 37 is positioned on top of the shadow mask electrode.31'as will'be described below. Also shown are integral lockin projection members 13 which will b'e'more 'fully described below.
  • FIG. 3 there is shownaside sectional view of a detail of a cathoderay tube showing-'how the electron beam shield member 37 may be positioned in one embodiment of our invention.
  • the face panel portion 13 of the 'envelope 11 is shown including the skirt portion 17 and a part of the faceplate portion 15.
  • the shadow mask electrode 31 rests upon a support land member 45.
  • a fastening spring member 47 is inserted into a'notch '59 in a lock-in projection member 43.
  • the fastening spring member 47 is also attached to a hold-down 'ring member 49 to which is iattached an electron beam shield positioning member 51 which holds the electron beam shield member 37 against the shadow mask electrode 31.
  • a suitable material -for the fastening spring member 47 is spring temper metalsold underthe trademark Inconel.
  • the electronbeam shield positioning member'Sl ' may'also be made of Inconel and maybe of either wire or flat stock.
  • the hold-down'spring member 49 may be a wire to which an lnconel leaf spring electron beam shield positioning member 51 is welded.
  • the electron beam shield member may be made of aluminum having a thickness of .010 to .0015". This aluminum may be stamped from aluminum sheeting of desired thickness and after -proper cleaning it may be inserted into the cathode ray tube.
  • An aluminum electron beam shield member 37 will allow direct contact with the glass envelope member 11 thereby giving complete electron beam shielding because the electrons are not'allowed to pass between the electron beam shield member 37 and the skirtportion of theenvelope member 11. 'Also aluminum will not damage the glass during the heating cycles in the manufacture ofcathoderay tubes, thus eliminating a source of possible breakage.
  • Figs. 4, '5 and 6 thereare shown portions of the part of the face panel portion 13-including the skirt portion'17 and-thefaceplate portion 15.
  • the shadow mask electrode :31 is positioned upon 'a support land member 45 and the electron beam shield member '61 is held by a one piece electron beam shield positioning member 53.
  • a portion of this electron beam shield positioningmember '53 is inserted in the notch 59 of the lock-in projection member 43.
  • Another portion of'the electron beam shield positioning member holds the elec 'tron'beam shield :member 61 in touching relationship to the shadow mask'electrode 31.
  • any slight deviation on the construction of the electron beam shield member 61 will not distort the shadow mask '31.
  • Theembossed portions 55 of the elec tron beam shi'eldmember 61 also providesan easy means of checking the seating of the electron beam shielding positioning member.
  • Fig. 7 there is shown another embodiment of our invention'in*which"portions of electron'beam shield members 57 are used rather than the electron beam shield member 37 or 61 shown in previous figures.
  • the skirt portion 17 of the face panel portion 13, the shadow mask electrode 31 and the electron beam shield positioning members 53 are also shown.
  • the partial electron beam shield member 57 as shown in Fig. 7, has in some instances, proven to provide suflicient electron beam shielding when located in the corner portions of the shadow mask electrode 31. This is primarily because the standard rectangular scanning pattern causes extensive bombardmentof the tube walls at the rounded corners of the customary 'znominally rectangular glass .tube envelope. It has also 'been found that the shadow mask electrode 31 may be positioned more closely to the glass envelope 11 in the flatter portions of the peripheryof the shadow mask electrode 31 but it is difficult to make such a close fit in the corners of the shadow mask electrode 31.
  • the electron beam shield member 37 of thinaluminumfoil such :as that knownas Reynolds Wrap. We have found that if this .thin aluminum foil is cut in strips having a width of approximately 6 inches and is folded'twicelleaving a strip 1 /2 inches wide with the thickness 4 times the original foil, this latter strip maythen be formedaround a die to the desirable shape. After the'shadow'mask.electrode31 has been permanently inserted in the cathode .ray tube the electron beam shield member.37 is then positionednext to the mask electrode 31Iand is held by positioning means as described above or by-anyother means.
  • this foil electron beam shield member .37 provides the necessary electron beam shielding as wellas the arc protection of the luminescent screen '25. Also, the aluminum foil electron beam shield member 37 does not distort the shadow mask electrode 31 during heating cycles and 'does not scratch theglass panel.
  • an electron beam shield member 37 made of aluminum foil holds its shape during the steps of preheating, electric sealing, annealing, exhaust and bake-out and while operating as a cathode ray tube. As can also be seen, it can be produced easily and cheaply.
  • Another advantage of using the fastening means described above is that the mask is allowed to breathe during the sealing and annealing cycles, therefore following more closely th'edirect contour changes of the glass panel.
  • a cathode ray tube including an envelope member, said envelope member being comprised of a face-plate portion and a funnel portion, said funnel portion being comprised of a flared portion and a neck portion, an electron beam generating means positioned within the neck portion of said envelope member, a luminescent screen positioned adjacent said face plate portion, a shadow mask electrode having a plurality of apertures therein positioned between said luminescent screen and said electron beam generating means and a thin flexible metallic electron beam shield member positioned between said shadow mask electrode and said electron beam generating means and positioned adjacent said envelope member, said'lectronbeam shield member being comprised o'f aluminum foil material.
  • an electron beam shield member comprising a thin, flexi- 6 References Cited in the file of this patent UNITED STATES PATENTS Beckers Dec. 1, 1953 Fyler et al. Sept. 28, 1954 Lawrence Nov. 23, 1954 Law Nov. 1, 1955 McQuillen et al. Sept. 10, 1957

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  • Electrodes For Cathode-Ray Tubes (AREA)
US578624A 1956-04-17 1956-04-17 Cathode ray tube Expired - Lifetime US2906904A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
NL216226D NL216226A (enrdf_load_stackoverflow) 1956-04-17
US578624A US2906904A (en) 1956-04-17 1956-04-17 Cathode ray tube
GB12245/57A GB813954A (en) 1956-04-17 1957-04-15 Improvements in or relating to cathode ray tubes
FR1171257D FR1171257A (fr) 1956-04-17 1957-04-16 écran de faisceau électronique pour tube à rayons cathodiques

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US578624A US2906904A (en) 1956-04-17 1956-04-17 Cathode ray tube

Publications (1)

Publication Number Publication Date
US2906904A true US2906904A (en) 1959-09-29

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Family Applications (1)

Application Number Title Priority Date Filing Date
US578624A Expired - Lifetime US2906904A (en) 1956-04-17 1956-04-17 Cathode ray tube

Country Status (4)

Country Link
US (1) US2906904A (enrdf_load_stackoverflow)
FR (1) FR1171257A (enrdf_load_stackoverflow)
GB (1) GB813954A (enrdf_load_stackoverflow)
NL (1) NL216226A (enrdf_load_stackoverflow)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2939981A (en) * 1958-03-07 1960-06-07 Paramount Pictures Corp Grid frame support structures for cathode ray tubes
US3333134A (en) * 1964-06-12 1967-07-25 Rca Corp Shadow mask frame with curved supporting flange paralleling screen surface
US3358170A (en) * 1962-01-11 1967-12-12 Rauland Corp Color television picture tube and mating support members for mounting the color selection mask within the tube
US3404302A (en) * 1967-06-21 1968-10-01 Gen Electric Envelope wall with two continuous ledges for positioning and supporting aperture mask
US3449612A (en) * 1968-04-24 1969-06-10 Sylvania Electric Prod Color cathode ray tube having shadow mask frame formed to accommodate a support system
US3450920A (en) * 1967-01-13 1969-06-17 Philips Corp Faceplate with land portions having two cavities for receiving shadow mask support members
US3473065A (en) * 1966-01-18 1969-10-14 Nat Video Corp Over-scanning shield provided in colored television tube between the mask support and the tube
US3601650A (en) * 1969-08-11 1971-08-24 Zenith Radio Corp Integrated shadow mask structure
US3873874A (en) * 1974-02-20 1975-03-25 Gte Sylvania Inc Shield attached by sealing to panel sidewall of cathode ray tube
US4002941A (en) * 1966-10-27 1977-01-11 Rca Corporation Shadow mask cathode ray tube shield
US4100451A (en) * 1974-08-19 1978-07-11 Zenith Radio Corporation Face panel assembly for a color cathode ray tube
US4670686A (en) * 1986-04-29 1987-06-02 Rca Corporation CRT internal magnetic shield contact spring

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3308327A (en) * 1964-06-12 1967-03-07 Rca Corp Cathode ray tube

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2661437A (en) * 1951-06-19 1953-12-01 Nat Union Radio Corp Dark trace cathode-ray tube
US2690518A (en) * 1953-06-01 1954-09-28 Columbia Broadcasting Syst Inc Color picture tube
US2695372A (en) * 1951-10-23 1954-11-23 Chromatic Television Lab Inc Grid structure for cathode-ray tubes
US2722623A (en) * 1953-03-31 1955-11-01 Rca Corp Color-kinescopes etc.
US2806162A (en) * 1954-08-18 1957-09-10 Rca Corp Cathode-ray tube

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2661437A (en) * 1951-06-19 1953-12-01 Nat Union Radio Corp Dark trace cathode-ray tube
US2695372A (en) * 1951-10-23 1954-11-23 Chromatic Television Lab Inc Grid structure for cathode-ray tubes
US2722623A (en) * 1953-03-31 1955-11-01 Rca Corp Color-kinescopes etc.
US2690518A (en) * 1953-06-01 1954-09-28 Columbia Broadcasting Syst Inc Color picture tube
US2806162A (en) * 1954-08-18 1957-09-10 Rca Corp Cathode-ray tube

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2939981A (en) * 1958-03-07 1960-06-07 Paramount Pictures Corp Grid frame support structures for cathode ray tubes
US3358170A (en) * 1962-01-11 1967-12-12 Rauland Corp Color television picture tube and mating support members for mounting the color selection mask within the tube
US3333134A (en) * 1964-06-12 1967-07-25 Rca Corp Shadow mask frame with curved supporting flange paralleling screen surface
US3473065A (en) * 1966-01-18 1969-10-14 Nat Video Corp Over-scanning shield provided in colored television tube between the mask support and the tube
US4002941A (en) * 1966-10-27 1977-01-11 Rca Corporation Shadow mask cathode ray tube shield
US3450920A (en) * 1967-01-13 1969-06-17 Philips Corp Faceplate with land portions having two cavities for receiving shadow mask support members
US3404302A (en) * 1967-06-21 1968-10-01 Gen Electric Envelope wall with two continuous ledges for positioning and supporting aperture mask
US3449612A (en) * 1968-04-24 1969-06-10 Sylvania Electric Prod Color cathode ray tube having shadow mask frame formed to accommodate a support system
US3601650A (en) * 1969-08-11 1971-08-24 Zenith Radio Corp Integrated shadow mask structure
US3873874A (en) * 1974-02-20 1975-03-25 Gte Sylvania Inc Shield attached by sealing to panel sidewall of cathode ray tube
US4100451A (en) * 1974-08-19 1978-07-11 Zenith Radio Corporation Face panel assembly for a color cathode ray tube
US4670686A (en) * 1986-04-29 1987-06-02 Rca Corporation CRT internal magnetic shield contact spring

Also Published As

Publication number Publication date
NL216226A (enrdf_load_stackoverflow)
GB813954A (en) 1959-05-27
FR1171257A (fr) 1959-01-23

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