US3904820A - Cathode-ray tube with implosion safety - Google Patents

Cathode-ray tube with implosion safety Download PDF

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Publication number
US3904820A
US3904820A US431669A US43166974A US3904820A US 3904820 A US3904820 A US 3904820A US 431669 A US431669 A US 431669A US 43166974 A US43166974 A US 43166974A US 3904820 A US3904820 A US 3904820A
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US
United States
Prior art keywords
tape
adhesive
ray tube
clamping band
cathode
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
US431669A
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English (en)
Inventor
Hendrik Bongenaar
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.)
US Philips Corp
Original Assignee
US Philips 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
Application filed by US Philips Corp filed Critical US Philips Corp
Application granted granted Critical
Publication of US3904820A publication Critical patent/US3904820A/en
Anticipated expiration legal-status Critical
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Classifications

    • 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

Definitions

  • ABSTRACT A cathode ray tube comprising implosion safety means having a fabric reinforced adhesive tape arranged around the tube and a clamping band on the tape. One of the surfaces adjoining the tape is roughened so as to receive the adhesive forced out of the tape during its compression by the band, and the reinforcement fabric is in contact with the roughened surface.
  • the invention relates to a cathode-ray tube for picture display having an implosion safety provided around the widest part of the tube, said implosion safety consisting of a fabric-reinforced adhesive tape which comprises a layer of adhesive, and at least one clamping band arranged over said adhesive tape.
  • a cathode-ray tube having such an implosion safety is known from the published Dutch Patent application 7,100,273.
  • the adhesive tape which is reinforced by means of a fabric, for example a glass fibre fabric, inter alia has the advantage of a large friction between the fabric and the glass envelope on the one hand and the fabric and the clamping band on the other hand. As stated in the said patent application, said friction is sufficiently large to prevent the sliding off of the clamping band from the slightly conical surface of the tube. A surface roughening on the outside of the envelope and the inside of the clamping band would therefor no longer be necessary.
  • a cathode-ray tube is characterized in that at least one of the surface enclosing the adhesive tape on either side has a surface unevenness in which the adhesive forced out of the adhesive tape upon providing the clamping band is received entirely or at least substantially entirely.
  • the invention is based on the recognition resulting from investigations that at the area where the clamping band exerts a large pressure on the adhesive tape the fabric present in said adhesive tape is compressed and the adhesive is forced out of the adhesive tape so that at that area an excess of adhesive is formed. Due to the presence of the fabric, it is difficult for said excess of adhesive to find an outlet in the lateral direction. A good contact of the fabric with the surfaces present on either side thereof is thus prevented, as a result of which the clamping band aided by the adhesive which now serves as a lubricant, slides off from the envelope.
  • the surface unevenness is present on the inside of the clamping band or on the outside of the envelope, or on both.
  • the choice of the surface to be roughened is determined by the way in which said surface unevenness can be realized with the minimum cost. This appears to be the case when simultaneously with the moulding of the display screen the required surface unevenness is also moulded in the outer surface of the upright edge of the display screen. This requires only a simple processing of the matrix by giving the surface thereof the required surface unevenness by slightly hammering in those places where this is desired.
  • a surface unevenness is preferably provided on the corners of the said upright edge.
  • the extent of surface unevenness depends upon the quantity of adhesive present in the adhesive tape per surface unit. When an average thickness is considered of the layer of adhesive present in the adhesive tape, the extent of the surface unevenness must be such that the adhesive forced out of said adhesive tape during providing the clamping band around the envelope is fully received by said surface unevenness. According to the invention this can be realized if the surface unevenness corresponds to an average roughness value which is at least equal to half the thickness of the layer of adhesive.
  • the maximum extent of the surface unevenness is determined by the way in which it is provided in the upright edge of the display screen. When the said unevenness is moulded in the upright edge, a certain value thereof should not be exceeded since otherwise the dis play screen can no longer be detached from the mould.
  • the conditions with respect to minimum and maximum surface unevenness can be satisfied, if, according to the invention, the surface unevenness corresponds to an average roughness value of 50 um to 500 ,um.
  • a cathode-ray tube is known from the U.S. Pat. No. 3,490,636 the upright edge of the display screen of which tube comprises at the corners thickened shoulders having grooves which extend in parallel to the tube axis and which, after providing the clamping band in the cold condition, are filled with an adhesive.
  • no fabric-reinforced adhesive tape is used.
  • it concerns grooves of comparatively coarse dimensions, as also shown in the drawing, so as to enable the filling thereof with adhesive and to obtain a large contact area of adhesive and clamping band.
  • the provision of such grooves requires either an expensive machining of the glass surface, or an expensive machining of the mould with the additional possibility of a larger reject percentage.
  • a cathode-ray tube is known from the U.S. Pat. No. 3,264,080 the upright edge of the display screen of which tube has ribs on the straight sides. In this case no clamping band is used and the ribs serve only to avoid the occurrence of scratches and other damage on the straight sides of the rectangular window.
  • the adhesive in the fabric-reinforced adhesive tape may consist of a synthetic material which softens at low temperature, for example, a rubber-containing synthetic material or a synthetic material which softens at high temperatures, for example, an acrylate-containing synthetic material.
  • the clamping band may be tightened around the envelope both in the cold condition and by means of a shrinkage process. In this latter method the clamping band is first heated to a temperature of 400 to 450C and then slid around the upright edge of the display screen. Upon cooling of the clamping band, shrinkage forces arise which, after cooling, provide the required stress in the clamping band.
  • FIG. 1 is a cross-sectional view of a surface unevenness on a considerably exaggerated scale.
  • FIG. 2 is a cross-sectional view of a fabric-reinforced adhesive tape
  • FIG. 3 is a cross-sectional view of a part of a cathoderay tube according to the invention.
  • the center line I having the roughness profile 2 encloses surfaces 3 the overall area of which on one side of the line I is equal to the overall area of the other side of the line I.
  • the value of the average roughness R, is equal to the average distance a of the roughness profile 2 to the center line 1 related on the base length L between the points A and B. So
  • the adhesive tape consists of a nonhardened adhesive 10 and a glass fibre fabric 11. As shown in FIG. 3, this tape is provided around the edge 12 of the display screen 14 which is covered on the inside with a phosphor screen 13. At the corners of the upright edge 12 the surface has a surface unevenness 15 in which the adhesive 17 forced out of the adhesive tape 9 by the clamping band 16 is accommodated.
  • the average roughness value of the surface unevenness I5 is um and is equal to half the thickness of the adhesive tape 9 which has a width of 19 mm. Since the excess of adhesive which mainly consists of acrylate resin is fully received by the surface unevenness 15, the glass fibre fabric 11 readily contacts both the clamping band 16 and the glass surface 18. The large friction between the clamping band and the glass fibre now fully prevents the sliding off of the clamping band.
  • a cathode ray tube for picture display having implosion safety means comprising a fabric reinforced adhesive tape provided around the widest part of the tube, a clamping band arranged on the upper surface of said tape, at least one of surfaces adjoining the tape on either side thereof being produced to an average roughness value of 50 #mto 500 ,um and the reinforcement fabric of said tape being in contact with the projecting areas of said roughened surface, whereby the recessed areas of said roughened surface being filled up by adhesive forced out of the tape during its clamping by the band.
  • a cathode-ray tube as claimed in claim 2 comprising a mainly rectangular display screen and wherein the surface unevenness is present at the corners of the upright edge of the display screen.

Landscapes

  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
US431669A 1973-02-12 1974-01-09 Cathode-ray tube with implosion safety Expired - Lifetime US3904820A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7301933.A NL163365C (nl) 1973-02-12 1973-02-12 Kathodestraalbuis met implosiebeveiliging.

Publications (1)

Publication Number Publication Date
US3904820A true US3904820A (en) 1975-09-09

Family

ID=19818187

Family Applications (1)

Application Number Title Priority Date Filing Date
US431669A Expired - Lifetime US3904820A (en) 1973-02-12 1974-01-09 Cathode-ray tube with implosion safety

Country Status (11)

Country Link
US (1) US3904820A (it)
JP (1) JPS5643591B2 (it)
BE (1) BE810860A (it)
BR (1) BR7400918D0 (it)
CA (1) CA1005110A (it)
DE (1) DE2405560C3 (it)
ES (1) ES423069A1 (it)
FR (1) FR2217796B1 (it)
GB (1) GB1425443A (it)
IT (1) IT1004899B (it)
NL (1) NL163365C (it)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4544955A (en) * 1984-01-30 1985-10-01 General Electric Company Implosion resistant cathode ray tubes

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3146305A (en) * 1961-12-14 1964-08-25 Motorola Inc Cathode ray tube protective front panel device
US3166211A (en) * 1960-11-03 1965-01-19 Philips Corp Glass cathode ray tube for reproducing images
US3490636A (en) * 1967-06-08 1970-01-20 Philips Corp Cathode-ray tube provided with at least one clamping band
US3818557A (en) * 1971-01-08 1974-06-25 Philips Corp Method of manufacturing an implosion-free picture tube for television display

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3264080A (en) * 1960-04-18 1966-08-02 Owens Illinois Inc Method for forming rectangular face plate
NL154864B (nl) * 1968-04-13 1977-10-17 Philips Nv Werkwijze voor het aanbrengen van een implosiebeveiligingsband om de ballon van een televisiebeeldbuis en een door middel van deze werkwijze vervaardigde televisiebeeldbuis.

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3166211A (en) * 1960-11-03 1965-01-19 Philips Corp Glass cathode ray tube for reproducing images
US3146305A (en) * 1961-12-14 1964-08-25 Motorola Inc Cathode ray tube protective front panel device
US3490636A (en) * 1967-06-08 1970-01-20 Philips Corp Cathode-ray tube provided with at least one clamping band
US3818557A (en) * 1971-01-08 1974-06-25 Philips Corp Method of manufacturing an implosion-free picture tube for television display

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4544955A (en) * 1984-01-30 1985-10-01 General Electric Company Implosion resistant cathode ray tubes

Also Published As

Publication number Publication date
NL163365C (nl) 1980-08-15
CA1005110A (en) 1977-02-08
BE810860A (fr) 1974-08-12
DE2405560A1 (de) 1974-08-15
GB1425443A (en) 1976-02-18
IT1004899B (it) 1976-07-20
DE2405560B2 (de) 1977-03-03
FR2217796B1 (it) 1976-11-26
DE2405560C3 (de) 1982-05-27
AU6535474A (en) 1975-08-07
NL7301933A (it) 1974-08-14
NL163365B (nl) 1980-03-17
FR2217796A1 (it) 1976-11-26
JPS49114343A (it) 1974-10-31
ES423069A1 (es) 1976-04-16
JPS5643591B2 (it) 1981-10-13
BR7400918D0 (pt) 1974-09-10

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