WO1998018151A1 - Implosion-resistant cathode ray tube envelope - Google Patents
Implosion-resistant cathode ray tube envelope Download PDFInfo
- Publication number
- WO1998018151A1 WO1998018151A1 PCT/US1997/018684 US9718684W WO9818151A1 WO 1998018151 A1 WO1998018151 A1 WO 1998018151A1 US 9718684 W US9718684 W US 9718684W WO 9818151 A1 WO9818151 A1 WO 9818151A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- panel
- compression
- psi
- thickness
- accordance
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J31/00—Cathode ray tubes; Electron beam 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
- H01J29/86—Vessels; Containers; Vacuum locks
- H01J29/87—Arrangements for preventing or limiting effects of implosion of vessels or containers
Definitions
- An envelope for a cathode ray tube especially the panel or face plate thereof.
- a cathode ray tube customarily has a glass envelope which is evacuated and hermetically sealed for tube operation.
- the envelope comprises a viewing panel member, a funnel member and a tubular neck member.
- An electron gun is mounted in the neck member.
- the panel member is often referred to as a face plate, or a display window, since it provides a screen on which a picture or display is formed.
- the panel member has a depending, peripheral skirt that is sealed to the funnel member with a fused sealing material.
- implosion protection band Such a band tightly encircles the skirt portion of the panel, and may be adherently sealed thereto.
- the protection band may be composed of metal or other strong materials.
- the present invention is directed to producing an improved envelope for a cathode ray tube.
- it is directed to the production of larger sized tubes in excess of a 19" panel dimension. It is further directed at minimizing the glass thickness in a cathode ray tube (CRT) panel while maintaining full protection against implosion. It is also directed to a method of producing a panel for a cathode ray tube that has minimum thickness consistent with full protection against implosion.
- CTR cathode ray tube
- the article of the invention is a glass envelope for a cathode ray tube comprising a panel member having a thickness (t) defined by the equation: wherein ( ⁇ ) P is the net tensile stress in the panel, (a) is one half the length of the minor axis in inches, (t) is the panel thickness in inches, (P) is atmospheric pressure in psi and
- (k) is a structural constant based on tube geometry.
- the panel has a net tensile stress not exceeding 1150 psi, a surface compression induced during panel manufacture, and an implosion protection band shrink-fitted around a skirt on the panel that augments surface compression in the panel, whereby the panel thickness is substantially less than that of a corresponding untreated tube envelope.
- FIGURE 1 in the accompanying drawing is a side view, partially cut away, illustrating a cathode ray tube in accordance with the invention.
- FIGURE 2 is a top plan view of the panel member of FIGURE 1.
- FIGURE 1 is a side view, partially cut away, illustrating a cathode ray tube construction generally designated 10.
- Tube 10 comprises the standard glass envelope members: viewing panel 12, funnel 14 and tubular neck 16.
- Electron gun 18 is mounted in neck member 16.
- Other tube components, not relevant to the present invention, such as a phosphor screen and a shadow mask, are omitted in the interest of clarity.
- Viewing panel 12 has a depending skirt portion 20. Panel 12 is joined to funnel 14 by a fusion seal 22 between the rims of skirt 20 and funnel 14.
- FIGURE 2 is a top plan view of rectangular panel member 12 showing the major axis 24 and the minor axis 26 in dashed lines. It has been found that the gusset region
- the present invention is aimed at reducing the thickness, and hence the weight, required to stay within the 1150 psi limit on tensile stress.
- the normal thickness of a tube panel can be reduced by anywhere from 10-35% depending on the consistency of manufacturing conditions. To accomplish this, we combine two means of inducing surface compression in the exterior surface of panel 12.
- Rapid cooling of panel member 12 during production can introduce significant levels of compression in the panel surface.
- surface compression levels ranging from 450-1650 psi can be introduced. To some extent, this surface compression may be lost during the thermal treatment inherent in an exhaust bake-out cycle. The tube is exposed to such cycle before being finally sealed. Allowing for a possible loss of up to 30%, compression stress values of at least 315- 1155 psi may be retained. This compression stress counters a tensile stress value of 1150 psi to such an extent that the net tensile stress is 835 psi.
- Air cooling is a preferred means of inducing the compression stress level in a glass panel.
- chemical tempering by ion exchange would be equally effective, albeit not as practical.
- Controlled release of forming stresses through heat treatment is also an effective way to introduce high surface compression in the CRT panel.
- the invention is further described with reference to a test in which several groups of sealed and evacuated CRTs were compared.
- the tubes in each group had essentially identical physical characteristics, but each group had different characteristics.
- each group had a unique combination of Center Face Thickness (CFT) values and High Surface Compression (HSC) values.
- CFT Center Face Thickness
- HSC High Surface Compression
- Center Face Thickness is the thickness in inches at the center of the tube panel.
- High Surface Compression is the compression in psi induced in the panel to counter tension developed by the pressure differential. The test was carried out over a period of
- the tests involve impact with a ball or missile of specified weight under specified conditions. They are designed to ensure the safety of viewers in case the CRT implodes due to heavy impact by a large object.
- the distance over which glass fragments are thrown out, in case of implosion, is limited by these tests to 0-5 ft. How far these fragments travel depends on two factors namely i) the size of the fragment and hence its mass, and ii) the energy to propel it.
- the former is influenced by the compressive stress induced by the band since higher compression will keep several fragments locked together thereby increasing their mass.
- the latter is composed of three sources of energy namely i) energy due to vacuum, ii) energy due to bending induced by pressure differential, and iii) energy due to local deformation induced by compressive stress from the band.
- the first two components of total energy are dictated by the size of CRT and hence are relatively fixed, i.e., they cannot be varied.
- the third component can be adjusted by controlling the compressive stress from the band by simply changing its width or thickness or both.
- the local deformation caused by the band alters the doming value of the panel at its center.
- the doming value is the distance that the central point on a tube panel rises, that is, bows outwardly or upwardly due to applied compressive stress. It should be noted that the center of the panel moves inward upon evacuation while the band helps bring it back to its original position. Thus, doming is the recovery value. A certain amount of doming is a necessary result of imparting the desired stress. However, tests have shown that doming must be limited to pass the safety tests. TABLE ⁇ sets forth the CFT and HSC values, as well as doming values measured on several sets of completed CRTs that were subjected to the UL and CSA tests. It also sets forth the width of the band employed to induce compression stress.
- the band plays a dual role.
- control of the band width controls doming, that is, the strain energy due to bending. Reducing the band width to 1.378" results in lower compression and less doming which help pass the implosion test as noted in TABLE ⁇ .
- a narrower band is required to pass the implosion test.
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/284,721 US6353283B1 (en) | 1997-10-20 | 1997-10-20 | Implosion-resistant cathode ray tube envelope |
PL97332942A PL190362B1 (en) | 1996-10-24 | 1997-10-20 | Crt glass bulb and method of making same |
BR9714618-8A BR9714618A (en) | 1996-10-24 | 1997-10-20 | implosion resistant cathode ray tube envelope |
EP97912742A EP0970501A4 (en) | 1996-10-24 | 1997-10-20 | Implosion-resistant cathode ray tube envelope |
JP10519490A JP2001502841A (en) | 1996-10-24 | 1997-10-20 | Implosion-resistant cathode ray tube envelope |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US2947696P | 1996-10-24 | 1996-10-24 | |
US60/029,476 | 1996-10-24 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1998018151A1 true WO1998018151A1 (en) | 1998-04-30 |
Family
ID=21849199
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1997/018684 WO1998018151A1 (en) | 1996-10-24 | 1997-10-20 | Implosion-resistant cathode ray tube envelope |
Country Status (9)
Country | Link |
---|---|
EP (1) | EP0970501A4 (en) |
JP (1) | JP2001502841A (en) |
KR (1) | KR20000052780A (en) |
CN (1) | CN1144253C (en) |
BR (1) | BR9714618A (en) |
CZ (1) | CZ135699A3 (en) |
RU (1) | RU2177188C2 (en) |
TW (1) | TW419701B (en) |
WO (1) | WO1998018151A1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9850162B2 (en) * | 2012-02-29 | 2017-12-26 | Corning Incorporated | Glass packaging ensuring container integrity |
US11179295B2 (en) | 2012-02-29 | 2021-11-23 | Corning Incorporated | Glass packaging ensuring container integrity |
JP5895719B2 (en) * | 2012-06-05 | 2016-03-30 | 東ソー株式会社 | Translucent ceramic joined body and manufacturing method |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5304890A (en) * | 1991-01-16 | 1994-04-19 | Mitsubishi Denki Kabushiki Kaisha | Cathode ray tube device having reinforcing frame |
US5445285A (en) * | 1993-06-30 | 1995-08-29 | Asahi Glass Company Ltd. | Glass bulb for a cathode ray tube |
US5466984A (en) * | 1991-12-26 | 1995-11-14 | Sony Corporation | Implosion-resistant band with stack retainer |
US5536995A (en) * | 1993-11-16 | 1996-07-16 | Asahi Glass Company Ltd. | Glass bulb for a cathode ray and a method of producing the same |
US5536996A (en) * | 1993-02-03 | 1996-07-16 | U.S. Philips Corporation | Anti-implosion band in a cathode ray tube having improved structure for protecting suspension elements |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3215765B2 (en) * | 1993-12-28 | 2001-10-09 | 三菱電機株式会社 | Picture tube manufacturing method |
-
1997
- 1997-10-20 WO PCT/US1997/018684 patent/WO1998018151A1/en not_active Application Discontinuation
- 1997-10-20 EP EP97912742A patent/EP0970501A4/en not_active Withdrawn
- 1997-10-20 JP JP10519490A patent/JP2001502841A/en not_active Ceased
- 1997-10-20 CZ CZ991356A patent/CZ135699A3/en unknown
- 1997-10-20 KR KR1019990703592A patent/KR20000052780A/en active IP Right Grant
- 1997-10-20 CN CNB971989508A patent/CN1144253C/en not_active Expired - Fee Related
- 1997-10-20 BR BR9714618-8A patent/BR9714618A/en not_active IP Right Cessation
- 1997-10-20 RU RU99111782/09A patent/RU2177188C2/en not_active IP Right Cessation
- 1997-10-21 TW TW086115745A patent/TW419701B/en not_active IP Right Cessation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5304890A (en) * | 1991-01-16 | 1994-04-19 | Mitsubishi Denki Kabushiki Kaisha | Cathode ray tube device having reinforcing frame |
US5466984A (en) * | 1991-12-26 | 1995-11-14 | Sony Corporation | Implosion-resistant band with stack retainer |
US5536996A (en) * | 1993-02-03 | 1996-07-16 | U.S. Philips Corporation | Anti-implosion band in a cathode ray tube having improved structure for protecting suspension elements |
US5445285A (en) * | 1993-06-30 | 1995-08-29 | Asahi Glass Company Ltd. | Glass bulb for a cathode ray tube |
US5536995A (en) * | 1993-11-16 | 1996-07-16 | Asahi Glass Company Ltd. | Glass bulb for a cathode ray and a method of producing the same |
Non-Patent Citations (1)
Title |
---|
See also references of EP0970501A4 * |
Also Published As
Publication number | Publication date |
---|---|
JP2001502841A (en) | 2001-02-27 |
CN1234135A (en) | 1999-11-03 |
BR9714618A (en) | 2000-05-09 |
CN1144253C (en) | 2004-03-31 |
KR20000052780A (en) | 2000-08-25 |
TW419701B (en) | 2001-01-21 |
EP0970501A1 (en) | 2000-01-12 |
RU2177188C2 (en) | 2001-12-20 |
CZ135699A3 (en) | 1999-12-15 |
EP0970501A4 (en) | 2000-01-12 |
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