US3422298A - Cathode ray tube having a non-discoloring x-ray absorptive display window - Google Patents

Cathode ray tube having a non-discoloring x-ray absorptive display window Download PDF

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Publication number
US3422298A
US3422298A US534309A US3422298DA US3422298A US 3422298 A US3422298 A US 3422298A US 534309 A US534309 A US 534309A US 3422298D A US3422298D A US 3422298DA US 3422298 A US3422298 A US 3422298A
Authority
US
United States
Prior art keywords
cathode
glass
window
ray tube
pane
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
US534309A
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English (en)
Inventor
Johannes De Gier
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Philips North America LLC
US Philips Corp
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US Philips Corp
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Publication date
Application filed by US Philips Corp filed Critical US Philips Corp
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Publication of US3422298A publication Critical patent/US3422298A/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
    • H01J29/86—Vessels; Containers; Vacuum locks
    • H01J29/87—Arrangements for preventing or limiting effects of implosion of vessels or containers
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
    • C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
    • C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
    • C03C3/087—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal containing calcium oxide, e.g. common sheet or container glass
    • 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
    • H01J29/86—Vessels; Containers; Vacuum locks
    • H01J29/863—Vessels or containers characterised by the material thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/87—Means for avoiding vessel implosion
    • H01J2229/875—Means substantially covering the output face, e.g. resin layers, protective panels

Definitions

  • the window comprises of a first portion adjacent the screen of poor electrical conductivity and containing a relatively small percentage of readily reducible compounds so that it will not discolor under impact of the electron beam while a second portion remote from the luminescent screen consists of a glass composition which contains lead oxide and cerium oxide in amounts eifective to absorb X-rays generated in the tube and transmitted through the first portion without discoloring due to the X-rays being absorbed on the electron impact.
  • the invention relates to a cathode-ray tube provided with a luminescent screen disposed on a glass window, which window has a composition such that it has a poor electrical conductivity and/ or that it contains a low percentage of readily reducible compounds such as oxides of lead, antimony and arsenic.
  • the glass window of a cathode-ray tube operating at a high voltage may exhibit a gradually increasing discolouration due to a prolonged electron bombardment.
  • Such voltages are used, for example, in cathode-ray tubes for projection television, for radar, for flying spot scanning, for colour television and in large cathode-ray tubes (having a diameter of, for example, more than 42 cm.) for black-andwhite television.
  • This discolouration may be accounted for by the reduction of oxides present in the glass due to charge transport. This discolouration is therefore counteracted by ensuring that the glass has a poor electrical conductivity or that it contains a low percentage of readily reducible compounds, while alternatively a combination of both steps may be used.
  • the glass should not contain more than 1% by weight of sodium oxide.
  • the content of readily reducible compounds does not exceed approximately 7.5% by weight in this case.
  • it is less simple to prepare glass having a low content of sodium oxide since such a kind of glass is excessively hard and its expansion coeflicient is excessively low 'while it is not readily meltable. It is therefore rather ensured that the glass contains a very low percentage of readily reducible compounds, i.e., not higher than 2.5% by weight, more particularly not higher than 1% by weight, in which 3,422,298 Patented Jan. 14, 1969 case the sodium oxide content does not exceed 10% by weight.
  • the permissible quantity of readily reducible compounds depends upon the sodium oxide content, while these two magnitudes in turn depend upon the actual charge of the cathode-ray tube during operation.
  • the said readily reducible compounds do not all contribute to the same extent to the discolouration of the glass. For example, a given content of lead oxide brings about a much stronger discolouration than the same quantity of antimony oxide, so that in a given case the permissible quantity of antimony oxide is greater than that of lead oxide.
  • X-rays the intensity of which strongly depends upon the actual charge of the cathode-ray tube, may penetrate through the glass window.
  • X-rays are readily absorbed by glass containing oxides of heavy metals, more particularly leadcontainin'g glass, but as set out hereinbefore, the glass window should preferably contain a very low percentage of lead oxide in order to prevent this window from being discoloured due to the electron bombardment. In practice, it has been found to be difficult to avoid the discolouration of the glass at voltages upwards of 25 kv.
  • the invention provides a solution in which on the one hand the discolouration of the glass window due to the electron bombardment is counteracted, while on the other hand the environment is protected against X-rays.
  • the cathode-ray tube is provided on the outer side at the area of the glass window with a pane containing lead oxide and cerium oxide.
  • the composition of the glass window prevents it from being discoloured due to the electron bombardment, while the X-rays produced in the cathode-ray tube are absorbed on the one hand in the pane as a result of the presence of the lead oxide, while on the other hand they do not bring about a discolouration in the pane owing to the presence of the cerium oxide.
  • the thickness of the glass pane amounts, for example, to 3 to 6 ms.
  • the intensity of the X-rays depends upon the actual charge of the cathoderay tube. In general, a pane containing from 5 to 15% by weight of lead oxide and up to 1% by weight of cerium oxide will prove satisfactory.
  • Cathode-ray tubes provided with a pane are known per se. In given cases, a pane is used for protection 3 4 against implosion. 'Ihis pane then has, for example, the under IV and V a few compositions of the pane 6. These following composition: compositions are stated in percentages by weight.
  • This pane has, for example, the A Cathode'ray tube havlhg a WlhdOW dlsplay foll wi i i of an image produced by impact of an electron beam on a percent b i h luminescent screen disposed on the lnternal surface of said s o 75 window, said window comprising a first portion adjacent 0 172 to the luminescent screen and consisting of a glass como ()2 position containing a relatively low percentage by weight A1203 of readily reducible compounds and having a relatively c o 7 g poor electrical conductivity whereby said portion does not o 3 discolor under impact thereon of the electron beam, and Remainder Q3 a second portion remote from said screen consisting of a glass composition containing lead oxide and cerium oxide
  • the Procfiss of manufacturing the P y Start from in amounts which are effective to absorb X-rays generated a fiat glass Plate which is allowed to bulge during heating in said tube and passing through said first portion without so that
  • the pane is moulded into the deby weight f Sodium id sired shape, whereupon it is adhered to the window of the 3 A cathode-ray b as l i d i l i 2, in hich tube.
  • the lnvention further relates to an apparatus comb i h of di id prising a cathode-ray tube provided with a luminescent 4 A cathode-ray t b as l i d i l i 2, i whi h Screen disposed on a glass Window, which Window has a the first window portion does not contain more than 2.5% composition such that it has a poor electrical conducb i h of dil d ibl id tivity and/or that it contains a low percentage of readily 5 A h d b as l i d i l i 3 i hi h reducible compounds such as oxides of lead, antimony thg fi t Window portion does not contain more than and arsenic.
  • a pane 15 P 6 in the apparatus by Weight f readily reducible i on the front slde of the cathode-ray tube a pane 15 P 6.
  • the the first Window pOrtion contains cerium Oxide composition of the glass window prevents it from being 7.
  • a pane UNITED STATES PATENTS containing from 5 to 15% by weight of lead oxide and 2,293,529 8/1942 Bedford 313-64 X up to 1% by weight of cerium oxide will generally prove 2,579,709 12/ 1951 Smith et a1.
  • 10653 satisfactory.
  • the cathode-ray tube are known per se.
  • Such a pane 2,856,303 10/1958 Armistead 106--53 serves, for example, for protection against implosion.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Glass Compositions (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
US534309A 1965-04-01 1966-03-15 Cathode ray tube having a non-discoloring x-ray absorptive display window Expired - Lifetime US3422298A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL6504105A NL6504105A (xx) 1965-04-01 1965-04-01

Publications (1)

Publication Number Publication Date
US3422298A true US3422298A (en) 1969-01-14

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ID=19792811

Family Applications (1)

Application Number Title Priority Date Filing Date
US534309A Expired - Lifetime US3422298A (en) 1965-04-01 1966-03-15 Cathode ray tube having a non-discoloring x-ray absorptive display window

Country Status (4)

Country Link
US (1) US3422298A (xx)
DE (1) DE1564395A1 (xx)
GB (1) GB1095867A (xx)
NL (1) NL6504105A (xx)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3543073A (en) * 1968-01-25 1970-11-24 Sheldon Edward E Vacuum tubes of television type for x-ray protection
US3610994A (en) * 1970-08-31 1971-10-05 Sheldon Edward E Cathode-ray tubes of television type for x-rays protection
US3663246A (en) * 1968-10-29 1972-05-16 Philips Corp Glass for television display cathode-ray tubes
US3947620A (en) * 1972-12-12 1976-03-30 Freeman Chemical Corporation Light transmissive laminates
FR2523367A1 (fr) * 1982-03-09 1983-09-16 Sony Corp Tube cathodique a liquide de refroidissement
US4483452A (en) * 1981-12-07 1984-11-20 Corning Glass Works Television bulb
US4485329A (en) * 1982-05-07 1984-11-27 North American Philips Consumer Electronics Corp. CRT Incorporating x-ray absorbing means
US4520115A (en) * 1982-08-02 1985-05-28 Schott Glaswerke High absorbance Pb-containing glass for cathode ray tube picture screen
US4645966A (en) * 1982-03-19 1987-02-24 U.S. Philips Corporation Display tube with fluid cooled window
JPS62283844A (ja) * 1986-05-30 1987-12-09 Nippon Sheet Glass Co Ltd 陰極線管用ガラス組成物
US4786619A (en) * 1986-06-30 1988-11-22 Pilkington Brothers P.L.C. Television face plates resistant to browning
US4930015A (en) * 1986-08-08 1990-05-29 Zenith Electronics Corporation Flat tension mask cathode ray tube implosion system
US5215944A (en) * 1991-07-29 1993-06-01 Ppg Industries, Inc. X-ray absorbing glass compositions
FR2740606A1 (fr) * 1995-10-27 1997-04-30 Toshiba Kk Tube renforcateur d'image radiographique
US6642163B2 (en) * 2000-12-25 2003-11-04 Nippon Electric Glass Co., Ltd. CRT funnel of a non beam-index type

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR860000969B1 (ko) * 1981-01-29 1986-07-23 가다야마 니하찌로오 음극선관
JPS59101747A (ja) * 1982-12-01 1984-06-12 Asahi Glass Co Ltd フエ−ス突出型ブラウン管
JPH07120514B2 (ja) * 1990-02-26 1995-12-20 三菱電機株式会社 陰極線管
JP2512204B2 (ja) * 1990-05-09 1996-07-03 三菱電機株式会社 投写型陰極線管

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR858667A (fr) * 1938-08-04 1940-11-30 Fernseh Ag Tube à rayon cathodique
US2293529A (en) * 1940-06-29 1942-08-18 Rca Corp Image tube
US2579709A (en) * 1948-09-22 1951-12-25 Pittsburgh Plate Glass Co Glass composition
US2676109A (en) * 1950-12-22 1954-04-20 American Optical Corp Glass
US2747105A (en) * 1951-11-29 1956-05-22 Pittsburgh Plate Glass Co Transparent nuclear radiation shield
US2856303A (en) * 1954-03-01 1958-10-14 Corning Glass Works Gamma-ray absorptive glass
US3209191A (en) * 1964-08-11 1965-09-28 Douglas Aircraft Co Inc Cathode ray tube screen and ambient light filter
US3356579A (en) * 1964-01-29 1967-12-05 Corning Glass Works Radiation window glass

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR858667A (fr) * 1938-08-04 1940-11-30 Fernseh Ag Tube à rayon cathodique
US2293529A (en) * 1940-06-29 1942-08-18 Rca Corp Image tube
US2579709A (en) * 1948-09-22 1951-12-25 Pittsburgh Plate Glass Co Glass composition
US2676109A (en) * 1950-12-22 1954-04-20 American Optical Corp Glass
US2747105A (en) * 1951-11-29 1956-05-22 Pittsburgh Plate Glass Co Transparent nuclear radiation shield
US2856303A (en) * 1954-03-01 1958-10-14 Corning Glass Works Gamma-ray absorptive glass
US3356579A (en) * 1964-01-29 1967-12-05 Corning Glass Works Radiation window glass
US3209191A (en) * 1964-08-11 1965-09-28 Douglas Aircraft Co Inc Cathode ray tube screen and ambient light filter

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3543073A (en) * 1968-01-25 1970-11-24 Sheldon Edward E Vacuum tubes of television type for x-ray protection
US3663246A (en) * 1968-10-29 1972-05-16 Philips Corp Glass for television display cathode-ray tubes
US3610994A (en) * 1970-08-31 1971-10-05 Sheldon Edward E Cathode-ray tubes of television type for x-rays protection
US3947620A (en) * 1972-12-12 1976-03-30 Freeman Chemical Corporation Light transmissive laminates
US4483452A (en) * 1981-12-07 1984-11-20 Corning Glass Works Television bulb
US4568852A (en) * 1982-03-09 1986-02-04 Sony Corporation Cathode ray tube with liquid coolant and reduced X-ray emission
FR2523367A1 (fr) * 1982-03-09 1983-09-16 Sony Corp Tube cathodique a liquide de refroidissement
US4645966A (en) * 1982-03-19 1987-02-24 U.S. Philips Corporation Display tube with fluid cooled window
US4485329A (en) * 1982-05-07 1984-11-27 North American Philips Consumer Electronics Corp. CRT Incorporating x-ray absorbing means
US4520115A (en) * 1982-08-02 1985-05-28 Schott Glaswerke High absorbance Pb-containing glass for cathode ray tube picture screen
JPS62283844A (ja) * 1986-05-30 1987-12-09 Nippon Sheet Glass Co Ltd 陰極線管用ガラス組成物
US4786619A (en) * 1986-06-30 1988-11-22 Pilkington Brothers P.L.C. Television face plates resistant to browning
US4930015A (en) * 1986-08-08 1990-05-29 Zenith Electronics Corporation Flat tension mask cathode ray tube implosion system
US5215944A (en) * 1991-07-29 1993-06-01 Ppg Industries, Inc. X-ray absorbing glass compositions
FR2740606A1 (fr) * 1995-10-27 1997-04-30 Toshiba Kk Tube renforcateur d'image radiographique
US5773923A (en) * 1995-10-27 1998-06-30 Kabushiki Kaisha Toshiba X-ray image intensifier tube
US6642163B2 (en) * 2000-12-25 2003-11-04 Nippon Electric Glass Co., Ltd. CRT funnel of a non beam-index type
US20040038798A1 (en) * 2000-12-25 2004-02-26 Nippon Electric Glass Co., Ltd. CRT funnel of a non beam-index type

Also Published As

Publication number Publication date
DE1564395A1 (de) 1969-10-16
GB1095867A (en) 1967-12-20
NL6504105A (xx) 1966-10-03

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