EP0254147A2 - Entladungslampe mit heisser Elektrode - Google Patents

Entladungslampe mit heisser Elektrode Download PDF

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Publication number
EP0254147A2
EP0254147A2 EP87109937A EP87109937A EP0254147A2 EP 0254147 A2 EP0254147 A2 EP 0254147A2 EP 87109937 A EP87109937 A EP 87109937A EP 87109937 A EP87109937 A EP 87109937A EP 0254147 A2 EP0254147 A2 EP 0254147A2
Authority
EP
European Patent Office
Prior art keywords
discharge lamp
tube
lamp apparatus
cathode electrode
semiconductor porcelain
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Withdrawn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
EP87109937A
Other languages
English (en)
French (fr)
Other versions
EP0254147A3 (de
Inventor
Shouichi Iwaya
Hitoshi Masumura
Munemitsu Hamada
Hiromi Ohfuna Seisakusho Mitsubishi Denki Adachi
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.)
Mitsubishi Electric Corp
TDK Corp
Original Assignee
Mitsubishi Electric Corp
TDK 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 claimed from JP1986108594U external-priority patent/JPH0512917Y2/ja
Priority claimed from JP1986108596U external-priority patent/JPH0514453Y2/ja
Application filed by Mitsubishi Electric Corp, TDK Corp filed Critical Mitsubishi Electric Corp
Publication of EP0254147A2 publication Critical patent/EP0254147A2/de
Publication of EP0254147A3 publication Critical patent/EP0254147A3/de
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/13—Solid thermionic cathodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/04—Electrodes; Screens; Shields
    • H01J61/06—Main electrodes

Definitions

  • the present invention relates to discharge lamp apparatuses, and more particularly to a hot cathode type discharge lamp apparatus.
  • a fluorescent lamp is known as a hot cathode type discharge lamp apparatus.
  • Cathode of the fluorescent lamp is constituted in process that electron emission material comprising oxides of barium, strontium and calcium as main constituent is applied to surface of a tungsten film in coil form.
  • the electron emission material is subjected to thermal decomposition corresponding to the electrode temperature, and active material with electron emission property, for example, Ba atom is produced.
  • the active material is transferred to the top end of the electrode due to surface diffusion thereby the work function at the top end of the electrode is lowered.
  • the thermal decomposition becomes rapid and supply of the active material becomes large, thereby evaporation of the active material from the electrode is increased and the evaporated material is adhered to the tube wall of the lamp and the tube wall is balckened. Consequently, the luminous flux of the lamp is deteriorated and the life of the lamp is decreased.
  • the prior art has problems in the activation of the electron emission material on the cathode surface, the blackening of the lamp, deterioration of the luminous flux and the decrease of the tube life.
  • an object of the invention is to provide a hot cathode type discharge lamp apparatus wherein a tube wall of a lamp (light emission tube) is prevented from being blackened, the luminous flux is not deteriorated, and the life of the tube becomes long.
  • a hot cathode type discharge lamp apparatus of the invention is composed of a discharge lamp tube, a cathode electrode member in nearly cylindrical form made of a semiconductor porcelain and arranged within the tube and having a discharge surface on a longitudinal circumferential surface, and two lead wires connected to both longitudinal ends of the cathode electrode member and penetrating an end portion of the discharge lamp tube.
  • a hot cathode type discharge lamp apparatus shown in FIG. 1 is composed of a tube 1 for discharge lamp, a cathode electrode member 2 using a semiconductor porcelain and arranged within the tube 1, and a pair of lead wires 3a, 3b which support the cathode electrode member 2 within the tube 1 and near an end portion 1a of the tube 1.
  • the cathode electrode member 2 is made of a semiconductor porcelain, and comprises a linear discharge surface 2a disposed on a longitudinal circumferential surface, a cylindrical base 2b, and lead wire connecting portions 2c, 2d formed respectively on both ends of the base 2b.
  • the lead wires 3a, 3b are arranged with prescribed spacing and penetrate the end portion 1a of the tube 1, and the penetrating portion is sealed by the end portion 1a.
  • Top end portions 3c, 3d extending within the tube 1 are wound on the lead wire connecting portions 2c, 2d so that the cathode electrode member 2 is supported within the tube 1 in parallel arrangement to the end portion 1a, and rear end portions 3e, 3f are projected to outside from the tube 1.
  • a power source is connected to the rear end portions 3e, 3f, thereby the cathode electrode member 2 is energized.
  • a conductive film 4 may be coated on both ends of the base 2b by means of evaporation, sputtering or the like so as to form lead wire connecting portions 12c, 12d.
  • contact resistance between the lead wires 3a, 3b and the base 2d can be reduced because of existence of the conductive film 4.
  • a semiconductor porcelain as a raw material for the cathode electrode 2 will now be described in detail.
  • a valency compensation type semiconductor porcelain may be mentioned as the semiconductor porcelain.
  • a typical example of the valency compensation type semiconductor porcelain is that using barium titanate.
  • the valency compensation as known well consists in that metal ion having valency different by value ⁇ 1 from that of constitution metal ion of metal oxide is added as an impurity, and increase or decrease of the charge quantity produced by introduction of the impurity is compensated by the number of valency of the constitution metal ion.
  • the valency compensation semiconductor forming agent can be exemplified by Y, Dy, Hf, Ce, Pr, Nd, Sm, Gd, Ho, Er, Tb, Sb, Nb, W, Yb, Sc, Ta or the like. These can be used together for adding. Adding amount of the adding agent is preferably 0.01 ⁇ 0.8 mol %, particularly 0.1 ⁇ 0.5 mol %.
  • a raw material to constitute the cathode electrode made of the semiconductor porcelain in the embodiment is preferably titanates.
  • titanates In addition to the above-mentioned barium titanate, strontium titanate, calcium titanate or lanthanum titanate may be used. Composite material of these may be used. Further, titanic acid in the titanates may be replaced by at least one of zirconic acid, silicic acid and stannic acid.
  • the semiconductor porcelain for the discharge electrode in the invention may be a forced reduction type semiconductor porcelain. This can be obtained by method of reducing the semiconductor porcelain for the cathode electrode as above described, and further by method of reducing without adding the semiconductor forming agent if the sufficient reducing condition is supplied. Reduction in this case may be performed in the reducing atmosphere of N2 or H2 and preferably in the temperature condition of 700°C or more, particularly in 1,200 ⁇ 1,450°C.
  • the electrode may be formed by using the valency compensation type and the forced reduction type together. Modes of the concurrent use are as follows:
  • Top end of a valency compensation type semi­conductor porcelain was ground into conical form of about 60°, and specific resistance of the obtained semiconductor porcelain was 9.9 ⁇ cm.
  • the H2 density was made 20 % in the reducing atmosphere of H2 + N2, and the semiconductor porcelain was reduced and burned at 1,250°C and the stabilizing time 2 Hr. Specific resistance of the burned porcelain was 0.90 ⁇ cm.
  • titanic acid in the titanates was replaced by at least one of zirconic acid, silicic acid and stannic acid.
  • the device comprises a polyethylene container 5 of 15 mm in width, 5 mm in length and 10 mm in height, and silver paste 6 is applied to the bottom surface of the container 5.
  • a specimen electrode 2 ⁇ was arranged above the bottom surface and an AC power source 7 was connected between the specimen electrode 2 ⁇ and the silver paste 6.
  • Radius R at the top end arc-shaped portion of the specimen electrode 2 ⁇ is made 20 ⁇ m, and distance D between the top end portion of the specimen electrode 2 ⁇ and the silver paste 6 is made 4 mm.
  • the starting voltage was 10 kV, and the voltage was increased in 1kV per minute.
  • the semiconductor porcelain for the cathode electrode in the embodiment has equivalent or more excellent characteristics in comparison to metals.
  • the cathode electrode 2 made of the semiconductor porcelain in the embodiment can obtain the stabilized discharge characteristics and the manufacturing cost can be decreased.
  • FIG. 5 shows a second embodiment of the invention.
  • a discharge lamp apparatus is composed of a tube 21 for discharge lamp, a cathode electrode member 22 using a semiconductor porcelain and arranged within the tube 21, and a pair of lead wires 23a, 23b which support the cathode electrode member 22 within the tube 21 and near an end portion 21a of the tube 21.
  • the cathode electrode member 22 is provided on both ends of a base 22b with lead wire connecting portions 22c, 22d having smaller diameter than that of the base 22b, and top end portions 23c, 23d of the lead wires 23a, 23b are wound respectively on the lead wire connecting portions 22c, 22d thereby the cathode electrode member 22 is supported.
  • the winding work of the lead wires becomes easy.
  • conductive films 34, 34 are coated on outer circumference of lead wire connecting portions 32c, 32d respectively. In such constitution, electric connection between the lead wires and the cathode electrode is secured.
  • a hot cathode type discharge lamp apparatus shown in FIG. 7 is composed of a tube 41 for discharge lamp, a cathode electrode member 42 using a semiconductor porcelain and arranged within the tube 41, and a pair of lead wires 43a, 43b which support the cathode electrode member 42 within the tube 41 and near an end portion 41a of the tube 41.
  • the cathode electrode member 42 comprises a cylindrical base 42b having a linear cylindrical discharge surface 42a, and lead wire connecting portions 42c, 42d formed respectively on both ends of the base 42b.
  • the lead wire connecting portions 42c, 42d are formed into grooves by cutting the base 42b at slightly inner portions from both ends.
  • the lead wires 43a, 43b are arranged with prescribed spacing and penetrate the end portion 41a of the tube 41, and the penetrating portion is sealed by the end portion 41a.
  • Top end portions 43c, 43d extending within the tube 41 are wound on the lead wire connecting portions 42c, 42d in arbitrary turns so that the cathode electrode member 42 is supported within the tube 41 in parallel arrangement to the end portion 41a, and rear end portions 43e, 43f are projected to outside from the tube 41.
  • a power source is connected to the rear end portions 43e, 43f, thereby the cathode electrode member 42 is energized.
  • the wound lead wires are not moved outwards and not slipped away.
  • a cathode member 52 may be used where a conductive film 54 is coated on outer circumference of lead wire connecting portions 52c, 52d by means of evaporation, sputtering or the like.
  • contact resistance between the lead wires 53a, 53b and the cathode electrode member 52 can be reduced because of existence of the conductive film 54.
  • the hot cathode type discharge lamp apparatus of the invention since an electron emission material is not used in the cathode electrode but the semiconductor porcelain is used, chemical reaction due to heating is not produced, thereby blackening phenomenon of the tube wall of the light emission tube can be prevented and the life of the discharge lamp apparatus becomes long. Also, since the semiconductor pocelain is cheap, cost of the apparatus is reduced. Further, since the semiconductor porcelain may be formed in any shape, shape of the semiconductor may be selected corresponding to the use object so as to obtain required characteristics.

Landscapes

  • Discharge Lamp (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
EP87109937A 1986-07-15 1987-07-09 Entladungslampe mit heisser Elektrode Withdrawn EP0254147A3 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP108594/86 1986-07-15
JP1986108594U JPH0512917Y2 (de) 1986-07-15 1986-07-15
JP108596/86 1986-07-15
JP1986108596U JPH0514453Y2 (de) 1986-07-15 1986-07-15

Publications (2)

Publication Number Publication Date
EP0254147A2 true EP0254147A2 (de) 1988-01-27
EP0254147A3 EP0254147A3 (de) 1990-03-21

Family

ID=26448436

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87109937A Withdrawn EP0254147A3 (de) 1986-07-15 1987-07-09 Entladungslampe mit heisser Elektrode

Country Status (3)

Country Link
EP (1) EP0254147A3 (de)
KR (1) KR920001845B1 (de)
CN (1) CN1006343B (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1043751A1 (de) * 1999-04-07 2000-10-11 Philips Corporate Intellectual Property GmbH Gasentladungslampe
US7103186B1 (en) 1998-05-16 2006-09-05 Joachim Brilka Stereo/two-tone demodulator

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4112449B2 (ja) * 2003-07-28 2008-07-02 株式会社東芝 放電電極及び放電灯

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2251045A (en) * 1929-06-29 1941-07-29 Gen Electric Gaseous electric discharge device
US3766423A (en) * 1971-12-03 1973-10-16 Itt Integral emissive electrode

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2251045A (en) * 1929-06-29 1941-07-29 Gen Electric Gaseous electric discharge device
US3766423A (en) * 1971-12-03 1973-10-16 Itt Integral emissive electrode

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7103186B1 (en) 1998-05-16 2006-09-05 Joachim Brilka Stereo/two-tone demodulator
EP1043751A1 (de) * 1999-04-07 2000-10-11 Philips Corporate Intellectual Property GmbH Gasentladungslampe

Also Published As

Publication number Publication date
KR920001845B1 (ko) 1992-03-05
KR880002216A (ko) 1988-04-29
CN1006343B (zh) 1990-01-03
CN87104929A (zh) 1988-01-27
EP0254147A3 (de) 1990-03-21

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Inventor name: ADACHI, HIROMIO

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Inventor name: MASUMURA, HITOSHI