EP0441387A2 - Lampe à décharge au gaz à basse pression - Google Patents

Lampe à décharge au gaz à basse pression Download PDF

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Publication number
EP0441387A2
EP0441387A2 EP91101715A EP91101715A EP0441387A2 EP 0441387 A2 EP0441387 A2 EP 0441387A2 EP 91101715 A EP91101715 A EP 91101715A EP 91101715 A EP91101715 A EP 91101715A EP 0441387 A2 EP0441387 A2 EP 0441387A2
Authority
EP
European Patent Office
Prior art keywords
bulb
pinch seal
low pressure
pressure gas
gas discharge
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.)
Withdrawn
Application number
EP91101715A
Other languages
German (de)
English (en)
Other versions
EP0441387A3 (en
Inventor
Kuniharu Kikuchi
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.)
Toshiba Lighting and Technology Corp
Original Assignee
Toshiba Lighting and Technology 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 Toshiba Lighting and Technology Corp filed Critical Toshiba Lighting and Technology Corp
Publication of EP0441387A2 publication Critical patent/EP0441387A2/fr
Publication of EP0441387A3 publication Critical patent/EP0441387A3/en
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/36—Seals between parts of vessels; Seals for leading-in conductors; Leading-in conductors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/36—Seals between parts of vessels; Seals for leading-in conductors; Leading-in conductors
    • H01J61/366—Seals for leading-in conductors
    • H01J61/368—Pinched seals or analogous seals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/70—Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr
    • H01J61/76—Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr having a filling of permanent gas or gases only
    • H01J61/78—Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr having a filling of permanent gas or gases only with cold cathode; with cathode heated only by discharge, e.g. high-tension lamp for advertising

Definitions

  • the present invention relates to a low pressure gas discharge lamp and more particularly to a sealing structure of a low pressure gas discharge lamp wherein an electrode and an exhaust tube are attached to a pinch seal portion formed in an end portion of a light-emitting bulb.
  • a low pressure gas discharge lamp such as a cold cathode fluorescent lamp serving as a scanner light source in electric equipments such as a facsimile machine or a copy machine or a backlight used in a liquid crystal display.
  • an extremely thin cold cathode fluorescent lamp has been used in a needle of a measuring instrument meter.
  • Such a cold cathode fluorescent lamp seals a cold cathode formed of a nickel plate to the end portion of light-emitting bulb formed of glass, and forms a fluorescent phosphor film in an inner surface of the light-emitting bulb. Also, mercury and rare gas are sealed in the light-emitting bulb.
  • flare stem which is generally used in a conventional hot cathode fluorescent lamp, or bead stem is used to seal an opening end of the bulb is sealed
  • flare or bead stem is unfavorable to the use of the thin bulb since the outer diameter of flare is larger.
  • the end portion of the bulb is sealed by the flare stem or the bead stem, since the distance between the sealed end portion and the top end of the electrode becomes large, that is, the height of the electrode becomes higher, an effective light-emitting length to the full length of the lamp is shortened.
  • the diameter of the bulb can be reduced and the height of the electrode can be lowered, and no special stem is required, so that the manufacture of the lamp can be easily made.
  • the cold cathode comprises a lead wire formed of a dumet wire and an electrode head formed of nickel connected to the top end of the lead wire.
  • the lead wire is airtightly inserted into the pinch seal portion.
  • the lead wire is airtightly inserted into the pinch seal portion in a state that the lead wire and the exhaust tube are arranged in the pinch seal portion along the width direction of the seal portion.
  • An object of the present invention is to provide a low pressure gas discharge lamp wherein the number of parts is small, assembly work is easily performed, sealing can be surely performed and the generation of leakage can be prevented.
  • the present invention provides a low pressure gas discharge lamp comprising a light-emitting bulb having a pinch seal portion formed in an bulb end portion, an exhaust tube airtightly inserted into and arranged at said pinch seal portion, one lead wire airtightly inserted into and arranged at said pinch seal portion, a pair of electrodes generating discharge therebetween, one of which is positioned in said bulb and jointed to said one lead wire, wherein said tube and said one lead wire are located side by side so that a central axis of said bulb is positioned between said tube and said one lead wire.
  • the lead wire and the exhaust tube can be arranged in parallel with each other to be separated at the central axis of the bulb along the width direction of the pinch seal portion, the lead wire and the exhaust tube can be surely sealed to the pinch seal portion even if the space of the pinch seal portion is small, and the generation of leakage can be prevented.
  • Fig. 1 is a side view showing the whole structure of a cold cathode fluorescent lamp of an A.C. lighting type or a high frequency lighting type.
  • Figs. 2 and 3 are cross sectional views showing an end portion of the lamp, respectively.
  • Figs. 4 and 5 are cross sectional views taken along lines IV-IV and V-V of Fig. 2.
  • reference numeral 1 is a light-emitting bulb of a cold cathode fluorescent lamp.
  • the light-emitting bulb is formed of a straight-typed glass tube having an outer diameter of 6 mm or less, for example, 5.6 mm, a thickness of 0. 4 mm, a full length of about 80 mm.
  • the bulb 1 has a bulb central axis O-O and both end portions, which are along the bulb central axis O-O, are sealed by pinch seal portions 2 and 3.
  • the pinch seal portions 2 and 3 are formed in such a manner that the bulb end portions are heated and softened and pressed from the side surfaces.
  • An electrode for example, cold cathodes 4 and 5 are sealed in the pinch seal portions 2 and 3, respectively.
  • the cold cathodes 4 and 5 are formed in such a manner that electrodes heads 6 and 7 are connected to lead wires 8 and 9, respectively.
  • the electrode heads 8 and 9 are formed of plate-like material made of metal such as nickel or mercury discharge material. Respective electrode heads 8 and 9 have width of 3.0 mm, length of 3.5 mm, thickness of 0. 5 mm, and getter 10, 10 is applied on the surface thereof.
  • the lead wires 8 and 9 are formed of a dumet wire of about 0.2 mm and sealed to the pinch seal portions 2 and 3 to be airtightly inserted thereinto along the direction of the bulb central axis O-O, respectively.
  • the respective lead wires 8 and 9 are linearly shaped and connected to one end of respective electrode heads 6 and 7 in the width direction of the electrode heads 6 and 7 by a spot-welding.
  • the top end portions 81 and 91 of the lead wires 8 and 9 are projected a discharge space of the bulb beyond the top ends of the electrode heads 6 and 7.
  • the electrode heads 6 and 7 are sealed to the pinch seal portions 2 and 3 at the position where the electrode central axis O1 - O1 coincides with the bulb central axis O - O or is close to the bulb central axis. Due to this, the lead wires 8 and 9 are sealed to the pinch seal portions 2 and 3 at the position which is deflected in one direction from the bulb central axis O - O.
  • the respective lead wires 8 and 9 are positioned to be deflected in the same direction from the bulb central axis O - O.
  • An exhaust tube 11 is airtightly inserted into only pinch seal portion 2.
  • the exhaust tube 11 is formed of a glass tube having an outer diameter of about 2.4 mm.
  • the exhaust tube 11 is sealed to the pinch seal portion 2 at the position which is deflected from the opposite side of the bulb central axis O - O.
  • the exhaust tube 11 and the lead wire 8 are provided side by side at the position where the exhaust tube 11 and the lead wire 8 are separated along the width direction of the pinch seal portion relative to the bulb central line O - O in the pinch seal portion 2.
  • a fluorescent phosphor film 12 is formed in the inner surface of the bulb 1. Also, predetermined amount of mercury and argon (Ar) gas are sealed in the bulb 1.
  • the electrode heads 6 and 7 of the cold cathodes 4 and 5 are respectively connected to the lead wires 8 and 9 and mechanically supported, the number of parts for supporting electrodes is reduced, and assembling time is shortened, and assembly work can be easily made.
  • the cold cathodes 4 and 5 are connected to the lead wires 8 and 9, respectively.
  • these lead wires 8 and 9 are respectively connected to the end portions of the electrode heads 6 and 7 in their width direction, the lead wires 8 and 9 are deflected one direction from the bulb central axis O - O and sealed to the pinch seal portions 2 and 3, thereby the central axis O1 - O1 of the electrode heads 6 and 7 can be positioned on bulb central axis O - O.
  • the lead wires 8 and 9 are connected to one side of the electrode heads 6 and 7, deflected one direction from the bulb central axis O - O, and sealed to the pinch seal portions 2 and 3, the lead wires can be linearly formed, and no special curving work is required. Due to this, time for forming the lead line can be shortened, and increase in the manufacturing cost can be prevented.
  • the bulb diameter can be reduced, the height of the electrode can be lowered, and no special stem is not required, the manufacture of the lamp can be easily made.
  • the electrode structure between both end portions becomes symmetric. Also, characteristic of luminous intensity distribution becomes symmetric along the bulb central axis O - O and scatter of luminous intensity distribution is reduced. Due to this, scatter of luminous intensity distribution, which is along the bulb central axis O - O, is reduced.
  • the exhaust tube 11 is attached to only pinch seal portion 2 and no exhaust tube 11 is attached to the pinch seal portion 3, the number of use of the exhaust tube is reduced and sealing is made easy. Moreover, the number of glass parts is reduced and the generation of cracks is lessened.
  • the top end portions 81 and 91 are projected to the discharge space beyond the electrode heads 6 and 7. Due to this, since electric field is concentrated on the protruded end portions 81 and 91, discharge is easily started and the characteristic of start is improved.
  • the different point from the first embodiment is that the end portion, which is introduced into the bulb 1 of a lead wire 80 is curved and the inner end portion is jointed to the electrode head 6 on the central axis O1 - O1 of the electrode head 6.
  • the central axis O1 - O1 of the electrode head 6 can be easily conformed to the bulb central axis O - O.
  • the third embodiment is different from the first embodiment in that the structure of the electrode head is different. More specifically, in the first embodiment, the electrode head is formed of one plate. However, in the third embodiment, the electrode head is formed of a plurality of plates. For example, an electrode head 60 is formed of two plates 61 and 62 having mercury discharge structure. In this case, two plates 61 and 62 sandwich the lead wire 8 therebetween and push each other in an inclined manner, and are substantially angular-shaped seen from the side view. Additionally, getter 10 is applied to the inner surfaces of the plates 61 and 62.
  • the shape of the electrode head is not limited.
  • the shape of the electrode head may be cylindrical or columnar.
  • the different point from the embodiment is that the electrode head 7 of the electrode 5, which is fixed to the pinch seal portion 3 having no exhaust tube 11, is held by a plurality of lead wires, for example, two lead wires 901 and 902.
  • two lead wires 901 and 902 are respectively jointed to both end portions of the electrode head 7 in its width direction.
  • the fifth embodiment shows a fluorescent lamp of d.c. lighting type.
  • a hot cathode is used as a positive electrode, that is, a coil filament 40, and a cold cathode 30 is used as a negative electrode.
  • the structure of the cold cathode 30 may be the same as that of Fig. 2 and the exhaust tube 11 is provided.
  • Lead wires 41 and 42 are connected to both end portions of the coil filament 40 serving as a positive electrode and the lead wires 41 and 42 are airtightly inserted into the pinch seal portion 3.
  • the number of lead line 8 to be connected to the cold cathode is one, the number of parts can be reduced. Also, since the lead wire 8 and the exhaust tube 11 can be arranged in parallel with each other to be separated at the central line of the bulb along the width direction of the pinch seal portion, the lead wire and the exhaust tube can be surely sealed to the pinch seal portion even if the space of the pinch seal portion is small.
  • mercury is sealed in the bulb.
  • noble gas discharge lamp in which xenon gas (Xe) in place of mercury is sealed may be used.
  • any lamps may be used if a lamp has a cold cathode.
  • the material of the cold cathode of the present invention may be aluminum, zirconium,tantalum, yttrium, or alloy of these materials, or boride, carbide, or nitride in place of nickel.
  • the shape of the lamp is not limited to the straight pipe, and an annular or U-shaped curved lamp may be used.
  • the sectional shape of the light-emitting bulb may be either a circle or an ellipse.
  • the other electrode may be an external electrode which is formed in the outer surface of the bulb.
  • the number of lead wires to be connected to the electrode is one, the number of parts is small. Also, since the lead wire and the exhaust pipe can be arranged in parallel with each other to be separated at the central line of the bulb along the width direction of the pinch seal portion, the lead wire and the exhaust pipe can be surely sealed to the pinch seal portion even if the space of the pinch seal portion is small. Due to this, the generation of leakage can be prevented even if the lamp having a small diameter is used.

Landscapes

  • Vessels And Coating Films For Discharge Lamps (AREA)
EP19910101715 1990-02-08 1991-02-07 Low pressure gas discharge lamp Withdrawn EP0441387A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP27073/90 1990-02-08
JP2027073A JPH03233854A (ja) 1990-02-08 1990-02-08 冷陰極けい光ランプ

Publications (2)

Publication Number Publication Date
EP0441387A2 true EP0441387A2 (fr) 1991-08-14
EP0441387A3 EP0441387A3 (en) 1992-04-15

Family

ID=12210897

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19910101715 Withdrawn EP0441387A3 (en) 1990-02-08 1991-02-07 Low pressure gas discharge lamp

Country Status (3)

Country Link
EP (1) EP0441387A3 (fr)
JP (1) JPH03233854A (fr)
KR (1) KR940006312B1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997024749A2 (fr) * 1995-12-29 1997-07-10 Philips Electronics N.V. Lampe a decharge basse pression
EP1388887A3 (fr) * 2002-08-05 2006-08-16 Nec Corporation Lampe à cathode froide et instrument électronique avec une telle lampe

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2056665A (en) * 1934-08-18 1936-10-06 Gen Electric Vapor electric discharge device
US2153009A (en) * 1935-09-10 1939-04-04 Gen Electric Electric discharge lamp
JPS63259958A (ja) * 1987-04-16 1988-10-27 Toshiba Corp セラミツク放電灯

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2056665A (en) * 1934-08-18 1936-10-06 Gen Electric Vapor electric discharge device
US2153009A (en) * 1935-09-10 1939-04-04 Gen Electric Electric discharge lamp
JPS63259958A (ja) * 1987-04-16 1988-10-27 Toshiba Corp セラミツク放電灯

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
INFORMATION DISPLAY. vol. 5, no. 11, November 1989, NEW YORK US pages 8 - 13; W. B. MERCER ET AL.: 'Fluorescent backlights for LCDs' *
PATENT ABSTRACTS OF JAPAN vol. 13, no. 78 (E-718)(3426) 22 February 1989 & JP-A-63 259 958 ( TOSHIBA CORP ) 27 October 1988 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997024749A2 (fr) * 1995-12-29 1997-07-10 Philips Electronics N.V. Lampe a decharge basse pression
WO1997024749A3 (fr) * 1995-12-29 1997-09-04 Philips Electronics Nv Lampe a decharge basse pression
CN1097293C (zh) * 1995-12-29 2002-12-25 皇家菲利浦电子有限公司 低压放电灯
EP1388887A3 (fr) * 2002-08-05 2006-08-16 Nec Corporation Lampe à cathode froide et instrument électronique avec une telle lampe

Also Published As

Publication number Publication date
KR910016044A (ko) 1991-09-30
JPH03233854A (ja) 1991-10-17
KR940006312B1 (ko) 1994-07-14
EP0441387A3 (en) 1992-04-15

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