WO2007119911A1

WO2007119911A1 - High brightness fluorescent lamp having electrode parts prepared by dielectric materials including ionic dipole or ionic and spontaneous polarization

Info

Publication number: WO2007119911A1
Application number: PCT/KR2006/003455
Authority: WO
Inventors: Man-Sun Yun; Chun-Woo Lee
Original assignee: Plasma Lamp Co., Ltd.
Priority date: 2006-04-17
Filing date: 2006-08-31
Publication date: 2007-10-25
Also published as: KR20070102772A; KR100849435B1

Abstract

Provided is a fluorescent lamp having dielectric electrode units. The fluorescent lamp includes a glass tube having both ends sealed, an inside surface coasted with fluorescent substance, and charging gas mixed with inert gas and hydrogen gas, and electrode units formed at both end of the glass tube, wherein the electrode units are formed by performing powder metallurgy with ferroelectric electrode material that has polar micro region and perovskite crystal structure which has higher dielectric constant and remanent polarization than that of glass material, moreover it has high density for bearing the sputtering phenomena due to collision of electrons and ions with electrode.

Description

Description HIGH BRIGHTNESS FLUORESCENT LAMP HAVING

ELECTRODE PARTS PREPARED BY DIELECTRIC MATERIALS INCLUDING IONIC DIPOLE OR IONIC AND

SPONTANEOUS POLARIZATION Technical Field

[1] The present invention relates to a fluorescent lamp, and more particularly, to a high brightness fluorescent lamp including electrode units formed of ferroelectric electrode material that has polar micro region and perovskite crystal structure which has higher dielectric constant and remanent polarization of than that of glass material and moreover it has high density for bearing the sputtering phenomena due to collision of electrons and ions with electrode. Background Art

[2] Referring to FIG. 1, a typical external electrode fluorescent lamp includes a glass tube 110 with both ends sealed and fluorescent substance coated on the inside surface thereof. The sealed glass tube 110 is filled with charging gas which is gas mixture of inert gas such Argon gas (Ar) or Neon gas (Ne) and hydrargyrum (Hg) gas. Various shapes of external electrodes coated with a conductive layer 121 such as silver or carbon are formed at the both ends of the glass tube 110, and metal caps 120 are inserted thereto.

[3] When high voltage of alterating current (AC) is applied to the conductive layer 121 of the external electrode fluorescent lamp 121, the both ends of the glass tube 110 function as a dielectric and form strong induced electric field.

[4] In more detail, if positive voltage is applied to the external electrode, electrons are accumulated in the inside of the glass tube 110 coated with the conductive layer 121. If negative voltage is applied to the external electrode, positive ion is accumulated. The accumulated wall charges reciprocate from one end to the other end of the glass tube 110 by continuously inverting the polarity through AC electric field. The reciprocated wall charge collides with hydrargyrum (Hg) gas in the inert gas, thereby inducing the hydrargyrum gas to be excited and to emit light. The excited hydrargyrum gas radiates ultraviolet ray, and the ultraviolet ray excites the fluorescent substance. As a result, the inside of the glass tube 110 excites and emits the light to the outside.

[5] In the conventional external electrode fluorescent lamp 110, the brightness of the lamp can increase by widening an area coated with the conductive layer 121, which functions as a dielectric in the glass tube 110, so as to increase the amount of wall charge as described above. Due to practical reason, there are many problems arisen if the length of the conductive layer 121 is lengthened. Disclosure of Invention

Technical Problem

[6] It is, therefore, an object of the present invention to provide a high brightness fluorescent lamp including electrode units connected at both ends of a glass tube or inserted into the both ends of the glass tube, wherein the electrode units are formed by performing powder metallurgy with ferroelectric electrode material that has polar micro region and perovskite crystal structure which has higher dielectric constant and remanent polarization (over 20μC/cm at lkV/mm)than that of glass material, moreover it has high density for bearing the sputtering phenomena due to collision of electrons and ions with electrode. Technical Solution

[7] According to one aspect of the present invention, there is provided a fluorescent lamp according to a first embodiment including a glass tube having both ends sealed, an inside surface coasted with fluorescent substance, and charging gas mixed with inert gas and hydrogen gas, and electrode units formed at both end of the glass tube, wherein each of the electrode units includes a body manufactured by power injection molding with ferroelectric electrode material that has polar micro region and perovskite crystal structure which has higher dielectric constant and remanent polarization ( 20μC/cm or moreat lkV/mm) than those of glass material and moreover it has high density for bearing the sputtering phenomena due to collision of electrons and ions with electrode and it has withstand voltage higher than about 1500Vrms/mn.

[8] The body according to the first embodiment may be formed in a hollow shape, a conductive layer is formed on an outer surface of the body, and the body is connected to the glass tube by adhering both ends of the body the glass tube using glass paste for sealing.

[9] According to another aspect of the present invention, there is provided a fluorescent lamp according to a second embodiment including a glass tube having both ends sealed, an inside surface coasted with fluorescent substance, and charging gas mixed with inert gas and hydrogen gas, and electrode units formed at both end of the glass tube, wherein each of the electrode units includes a body manufactured by power injection molding with ferroelectric electrode material that has polar micro region and perovskite crystal structure which has higher dielectric constant and remanent polarization (over 20μC/cm at lkV/mm) than that of glass material and moreover it has high density for bearing the sputtering phenomena due to collision of electrons and ions with electrode and it has withstand voltage higher than about 1500Vrms/mn. [10] The electrode unit according to the second embodiment may include the body formed in a hollow shape, flanges formed at both ends of the body and inserted and fixed to the glass tube, a ring protrusion formed at a center of outside surface of the body, and a conductive layer formed on the outside surface of the body, and wherein predetermined parts of the body, the flange, and the ring protrusion may be inserted into the glass tube and insulated by glass paste for sealing, and the remained part of the ring protrusion may be projected out of the glass tube so as to be fixed to the glass tube by glass paste for sealing.

[11] According to still another aspect of the present invention, there is provided a fluorescent lamp according to a third embodiment including a glass tube having both ends sealed, an inside surface coasted with fluorescent substance, and charging gas mixed with inert gas and hydrogen gas, and electrode units formed at both end of the glass tube, wherein each of the electrode units includes a body manufactured by power injection molding with ferroelectric electrode material that has polar micro region and perovskite crystal structure which has higher dielectric constant and remanent polarization (over 20μC/cm at lkV/mm) than that of glass material and moreover it has high density for bearing the sputtering phenomena due to collision of electrons and ions with electrode and it has withstand voltage higher than about 1500Vrms/mn.

[12] The electrode unit according to the third embodiment may include the body formed in a hollow shape, a conductive layer with a lead wire fixed to a principal part formed between an inner circumference member and an external circumference member, and sealing glass plates melted and jointed to both ends of the glass tube for sealing both ends of the glass tube, and wherein the lead wire may penetrate the sealing glass plate and be fixed at an outer surface of the sealing glass plate by glass paste for sealing, and an inside surface of the sealing glass plate may be joined to the internal circumference member and the external circumference member of the body.

[13] According to yet another aspect of the present invention, there is provided a fluorescent lamp according to a fourth embodiment including a glass tube having both ends sealed, an inside surface coasted with fluorescent substance, and charging gas mixed with inert gas and hydrogen gas, and electrode units formed at both end of the glass tube, wherein each of the electrode units includes a body manufactured by power injection molding with ferroelectric electrode material that has polar micro region and perovskite crystal structure which has higher dielectric constant and remanent po- larization (over 20μC/cm at lkV/mm) than that of glass material and moreover it has high density for bearing the sputtering phenomena due to collision of electrons and ions with electrode and it has withstand voltage higher than about 1500Vrms/mn.

[14] The electrode unit according to the fourth embodiment may include a conductive layer formed at one side of a lead wire having a bead glass for sealing, an area with the conductive formed may be inserted to a hollow of the body, and the body may be sealed with both ends of the glass tube by the bead glass with the body inserted into the both ends of the glass tube.

[15] The body according to the first to fourth embodiments may be formed by powder metallurgy with ferroelectric electrode material having ion and spontaneous polarization, which is formed by adding about 0 to 10 wt% of addictive including at least one of Y O , CeO , Cr O , and Fe O , to composition of a chemical formula 1.

2 3 2 2 3 2 3

[16] The additive including at least one of Y O , CeO , Cr O , and Fe O may be

^& 2 3 2 2 3 2 3 ^J substituted with other oxide having bivalent, trivalent, and pentavalent atomic values, for example, La O . ^r 2 3

[17] Chemistry Figure 1

A [Pb(Sb_{0 5}Nb_{0 5})O₃ ) - B [Pb(Mn _λ Sb ₂ )O₃) - [ 1 - (A + B))Pb(Zr_xTi ^_x)O₃

T T

[18] where 0<A≤0.05mol, 0<B≤0.05mol, and 0.45<x≤lmol.

[19] In a composition of A(Pb(Sb Nb )O } of the chemical formula 1, Sb may be replaced with Sb⁺ or another oxide having the same trivalent atomic value of Sb⁺ (For exam ^rple, Cr 2 O 3 , Sc 2 O 3 , Er 2 O 3 , and Yb 2 O y ). Nb may ^J be re ^rplaced with Nb⁺ or another oxide having the same pentavalent atomic value of the Nb⁺ (for example, Ta O ).

[20] In a composition of B(Pb(Mn Sb )O } of the chemical formula 1, Mn may be replaced with Mn⁺ or another oxide having the same bivalent atomic value of the Mn⁺ (for example, MgO, CdO, and NiO). Sb can be replaced with Sb⁺ or another oxide having the same pentavalent atomic value of Sb⁺ (for example, Nb O , and Ta O ).

[21] The body according to the first to fourth embodiment may be formed by powder metallurgy with ferroelectric electrode material having ion and spontaneous polarization, which is formed by adding about 10 to 25 wt% of SiO -BaO-CaO-Al O or BeO-CuO-SiO addictive to composition of a chemical formula 2 or a chemical formula 3.

[22] ChemistryFigure 2

(Ba_{1 ^}Ca_x)Ti _λ._y._zZr βn _ΣO '₃

[23] where 0mol<x≤0.2mol, 0.09mol≤y<0.14mol, and Omol≤z≤O. lmol.

[24] ChemistryFigure 3

( ^Ce i -_X^r_x)Zr y Ti _λ y -y O ₃

[25] where 0mol≤x≤0.2mol, and 0mol≤y≤0.03mol.

[26] Beside compositions in the chemical formulas 1 to 3, ferroelectric materials which have over 20μC/cm ofremanent polarizationat lkV/mm, can be used to manufacture the body according to the first to fourth embodiment. Advantageous Effects

[27] The ferroelectric electrode material has polar micro region and perovskite crystal structure which has higher dielectric constant and remanent polarization (over 20μC/cm at lkV/mm) than that of glass material and moreover it has high density for bearing the sputtering phenomena due to collision of electrons and ions with electrode. Therefore, more wall charges can be induced inside the glass tube in the same dielectric area, and the brightness of the lamp can be significantly improved by moving the charges. By controlling the size and shape of electrode units, which is formed by powder metallurgy with ferroelectric electrode material having ion and spontaneous polarization, in consideration of the brightness, a driving voltage for driving the lamp and the output of the lamp can be conveniently controlled.

Brief Description of the Drawings

[28] FIG. 1 is a cross-sectional view of a conventional external electrode fluorescent lamp. [29] FIG. 2 is a cross-sectional view of a fluorescent lamp according to a first embodiment of the present invention. [30] FIG. 3 is a diagram illustrating a method of manufacturing the fluorescent lamp shown in FIG. 2. [31] FIG. 4 is a cross-sectional view of a fluorescent lamp according to a second embodiment of the present invention. [32] FIG. 5 is a diagram illustrating a method of manufacturing the fluorescent lamp shown in FIG. 4. [33] FIG. 6 is a cross-sectional view of a fluorescent lamp according to a third embodiment of the present invention. [34] FIG. 7 is a diagram illustrating a method of manufacturing the fluorescent lamp shown in FIG. 6. [35] FIG. 8 is a cross-sectional view of a fluorescent lamp according to a fourth embodiment of the present invention. [36] FIG. 9 is a diagram illustrating a method of manufacturing the fluorescent lamp shown in FIG. 8.

[37] <Description of symbols in main parts of the drawings>

[38] 100, 200, 300, 400, 500: fluorescent lamp

[39] 110, 210, 211, 310, 311, 410, 510: glass tube

[40] 120: metal cap

[41] 220, 320, 420, 520: electrode unit

[42] 121, 221, 324, 423, 523: conductive layer

[43] 222, 321, 421, 524: body [44] 223, 325, 326, 424: sealing glass

[45] 322: flange

[46] 323: annular protrusion

[47] 421a: internal circumference member

[48] 421b: external circumference member

[49] 421c: principal part

[50] 422, 522: lead wire

[51] 425: sealing glass plate

[52] 426: stem glass

[53] 521: bead glass

Best Mode for Carrying Out the Invention

[54] Other objects and aspects of the invention will become apparent from the following description of the embodiments with reference to the accompanying drawings, which is set forth hereinafter.

[55] Hereinafter, a fluorescent lamp according to a first embodiment of the present invention will be described with reference to the accompanying drawings.

[56] Referring to FIG. 2, the fluorescent lamp 200 according to the first embodiment includes glass tubes 210 and 211, and electrode units 220 each functioning as an external electrode. In FIG. 2, a reference numeral 210 denotes a main glass tube 210, and a reference number 211 is a sealing glass tube 211. The sealing glass tube 211 is melted and sealed after injecting gas (refer to a diagram C of FIG. 3).

[57] Each of the electrode units 220 has a hollow body 222 formed by powder metallurgy with ferroelectric electrode material having ion and spontaneous polarization. A conductive layer 221 made of silver paste or carbon paste is formed on the outer surface of the body 222. The glass tubes 210 and 211 are connected by a sealing glass 223 having both ends made of glass paste.

[58] The fluorescent lamp 200 according to the first embodiment is manufactured as follows.

[59] Referring to FIG. 3, a predetermined length of a main glass tube 210 and sealing glass tubes 211 are prepared by opening both ends thereof, coating the inside surface thereof with fluorescent substance, drying them, and completely removing solvent and organic binder remained in the inside surface through a predetermined process (refers to A of FIG. 3).

[60] Then, hollow bodies 222 each having, for example, a thickness of about 1mm is formed by performing powder metallurgy with ferroelectric electrode material that has an ion and spontaneous polarizations. The ferroelectric electrode material is made by adding about 10 wt% of rare earth oxide addictive having Y O to composition like a following chemical formula 4 among compositions of the chemical formula 1. After forming the body 222 through injection-molding, the conductive layer 221 is formed by performing a firing process with silver paste at 600⁰C or coating carbon paste on the outer surface of the body 222. [61] Chemistry Figure 4

0.03 [Pb(Sb_{0 5}Nb_{0 5})O^ - 0.03 [Pb(Mn _x Sb ₂ )<9₃} - 0.94Pb(Zr_{0 50}Ti_{0 50})O₃

T T

[62] After preparing the bodies 222, one end of one of the bodies 222 is connected to one end of the main glass tube 210 through thermal process using sealing glass paste. Continually, one end of the other 222 is connected to the other end of the main glass tube 210 through thermal process using sealing glass paste. When they are connected, a sealing glass 223 is formed (refer to a diagram B in FIG. 3).

[63] Finally, one end of each body 222 connected to both ends of the glass tube 210 is connected to the sealed glass tube 211 using sealing glass paste through the same connecting method. Then, gas is exhausted and injected from/to the glass tubes 210 and 211 connected to the body 222 and the glass tube 211 is sealed, thereby completely manufacturing the fluorescent lamp 200 as shown in a diagram C in FIG. 3.

[64] In stead of using the ferroelectric electrode material having ion and spontaneous polarization, which is made by adding about 10 wt% of rare earth oxide addictive having Y O to composition like the chemical formula 4, the body 222 may be manufactured by performing powder metallurgy with ferroelectric electrode material having ion and spontaneous polarization, which is formed by adding about 10 to 25 wt% of SiO - BaO-CaO-Al O or BeO-CuO-SiO addictive to composition like a following chemical formula 5 that is induced from the chemical formula 2 with x = 0.15mol, y = 0.09mol<y≤0.14mol, and z = O.Oόmol.

[65] ChemistryFigure 5

(,Ba_{0 85}Cα_{0 15})v / _{Q 96}_yZry3fϊ _{Q Q4}Cy₃

[66] Furthermore, in stead of using the ferroelectric electrode material having ion and spontaneous polarization, which is made by adding about 10 wt% of rare earth oxide addictive having Y O to composition like the chemical formula 4, the body 222 may be manufactured by performing powder metallurgy with ferroelectric electrode material having ion and spontaneous polarization, which is formed by adding about 10 to 25 wt% of SiO 2 -BaO-CaO-Al 2 O 3 or BeO-CuO-SiO 2 additive to composition like a following chemical formula 6 that is induced from the chemical formula 3 with x = 0.3mol, and y = 0.03mol. [67] ChemistryFigure 6

[68] Hereinafter, a fluorescent lamp according to a second embodiment of the present invention will be described with reference to the accompanying drawings.

[69] Referring to FIG. 4, the fluorescent lamp 300 according to the second embodiment includes glass tubes 310 and 311 and electrode units 320 each functioning as external electrodes. In FIG. 4, a reference numeral 310 denotes a main glass tube and a reference numeral 311 denotes a sealing glass tube. The sealing glass tube 311 is melted and sealed after exhausting and injecting a gas (refer to a diagram D of FIG. 5).

[70] The electrode unit 320 includes a hollow body 321 formed by powder metallurgy with ferroelectric electrode material that has an ion polarization or ion and spontaneous polarization, flanges 322 each inserted and fixed in the inside of the glass tubes 310 and 322 at both ends of the body 321, a ring protrusion 323 formed on a center external surface of the body 321, and a conductive layer 324 made of silver paste or carbon paste formed on the outer surface of the body 321.

[71] Predetermined parts of the body 321, the flange 322, and the ring protrusion 323 are inserted in the glass tubes 310 and 311 and insulated by an inner sealing glass 325 made of sealing glass paste. The remained part of the ring protrusion 323 is projected out of the glass tubes 310 and 311 and fixed by an external sealing glass 326 made of sealing glass paste.

[72] Hereinafter, the fluorescent lamp 300 according to the second embodiment is manufactured as follows.

[73] Referring to FIG. 5, the glass tubes 310 and 411 are prepared by opening both ends, coating fluorescent substance on the inside surface, drying the coated fluorescent substance, and completely removing solvent or organic binder remained on the inside surface through a predetermined process (refers a diagram A of FIG. 5).

[74] Then, a pair of bodies 321 made of ferroelectric electrode material having ion and spontaneous polarization and including composition of the chemical formula 1 or the chemical formula 4 through powder metallurgy is prepared. After forming the bodies 321, a conductive layer 324 is formed on the outer surface by performing a firing process with silver paste at 600⁰C or is formed on the outer surface of the tube body 321 with carbon paste.

[75] After preparing a pair of the bodies 321, a sealing glass paste is coated on the outer surface between the flange 322 and the ring protrusion 323 of one of the bodies 321. Then, predetermined parts of the flange 322 and the ring protrusion 311 are inserted into and fixed to one end of the main glass tube 310 and one end of the sealing glass tube 311. Continuously, remained parts of the flange 322 and the ring protrusion 311 are inserted into and fixed to the other end of the main glass tube 310 and one end of the other sealing glass tube 311 with the same method.

[76] Since one end of the main glass tube 310 and one end of the sealing glass tube 311 are closely adhered to each other with the ring protrusion 323 interposed, the remained part of the ring protrusion 323 is projected out of the glass tubes 310 and 311, that is, between one end of the main glass tube 310 and one end of the sealing glass 311. An inner sealing glass 325 is formed by hardening sealing glass paste coated on the outer surface between the flange 322 and the ring protrusion 323, and the flange 322 prevents the sealing glass paste from flowing into the inside of the glass tubes 310 and 311 while firing the coated sealing glass paste (refer a diagram B of FIG. 5).

[77] After the predetermined parts of the bodies 321, the flange 322, and the ring protrusion 323 are inserted into and fixed at one end of the main glass tube 310 and one end of the sealing glass 311, the remained part of the ring protrusion 323 projected out of the glass tubes 310 and 311 is fixed using the sealing glass paste, thereby sealing the side of the projected part of the ring protrusion 323 and a gap between the glass tubes 310 and 311 (refer to a diagram C of FIG. 5).

[78] Finally, gas is exhausted from and injected into the glass tubes 310 and 311 fixed with a pair of the bodies 322 inserted, and the glass tube 311 is sealed, thereby completely manufacturing the fluorescent lamp 300 (refer to a diagram D of FIG. 5).

[79] In stead of using the ferroelectric electrode material having ion and spontaneous polarization and including composition of the chemical formula 4 or the chemical formula 1 to form the body 321, the body 321 can be manufactured through powder metallurgy with ferroelectric electrode material having ion and spontaneous polarization and including composition of the chemical formula 2 or the chemical formula 5, or the chemical formula 3 or the chemical formula 6.

[80] Hereinafter, a high brightness fluorescent lamp according to a third embodiment of the present invention will be described with the accompanying drawings.

[81] Referring to FIGs. 6 and 7, the fluorescent lamp 400 according to the third embodiment includes a glass tube 410 and electrode units 420 each functioning as an external electrode.

[82] Each of the electrode units 420 has a hollow body 421 and a conductive layer 423 with a lead wire 422 fixed to a principal part 412c formed between an inside diameter 421a and an external circumference member 421b, where the lead wire 422 may be a dumet wire formed by coasting nickel (Ni) steel with copper (Cu), which has the same linear expansivity of glass. The lead wire 422 penetrates a sealing glass plate 425 and fixed at the outer surface of the sealing glass plate 425 by an insulating sealing glass 424, and the inner side of the sealing glass plate 425 is connected to the internal circumference member 421a and the external circumference member 421b. The sealing glass plate 425 is melted and adhered to both ends of the glass tube 410 to seal both ends of the glass tube 410.

[83] A stem glass 426 extends from the center of the outer surface of the sealing glass plate 425 to exhaust and inject gas. After exhausting gas from and injecting gas into the glass tube 410, the stem glass 426 is removed and both ends of the glass tube 410 are sealed.

[84] The fluorescent lamp 400 according to the third embodiment is manufactured as follows.

[85] Referring to FIG. 7, the body 421 manufactured through powder metallurgy with ferroelectric electrode material having ion and spontaneous polarization and including composition of the chemical formula 1 or the chemical formula 4 is prepared. Then, silver paste is coated on the principal part 421c of the body 421. The lead wire 422 is inserted into the silver paste and a firing process is performed at about 600°C(refer to a diagram A of FIG. 7). As a result, the conductive layer 423 is formed.

[86] After forming the conductive layer 423 with the lead wire 422 fixed at the body

421, a half-finished electrode unit 420 is manufactured by connecting the inside surface of the sealing glass plate 423 to the internal circumference member 421a and the external circumference member 421b of the body 421 while inserting the lead wire 422 fixed at the conductive layer of the body 421 to a hole formed at the sealing glass plate 425 where the stem glass 426 extends from the center thereof (refer to a diagram B of FIG. 7). The sealing glass paste is hardened to fix the lead wire 422 at the outer surface of the sealing glass plate 425, thereby forming the insulating sealing glass 423a.

[87] After forming the half-finished electrode unit 420, a predetermined length of a glass tube 410 is prepared by coating fluorescent substance on the inside surface thereof, drying the coated fluorescent substance, and completely removing solvent or organic binder remained therein through a predetermined firing process. Then, the half-finished bodies 421 of the electrode units 420 are inserted into the both ends of the glass tube 410, and edges of the sealing glass plate 425 is melted and joined to the both ends of the glass tube 410 (refer to a diagram C of FIG. 7).

[88] Finally, gas is exhausted from and inserted into the glass tube 410 through the stem glass 426, the stem glass 426 is removed, and the glass tube 410 is sealed, thereby completely manufacturing the fluorescent lamp 400 (refer to a diagram D of FIG. 7).

[89] In stead of using the ferroelectric electrode material having ion and spontaneous polarization and including composition of the chemical formula 4 or the chemical formula 1, the body 421 can be manufactured through powder metallurgy with ferroelectric electrode material having ion and spontaneous polarization and including composition of the chemical formula 2 or the chemical formula 5, or the chemical formula 3 or the chemical formula 6. [90] Hereinafter, a fluorescent lamp according to a fourth embodiment of the present invention will be described with reference to accompanying drawings.

[91] Referring to FIG. 8 and FIG. 9, the fluorescent lamp 500 includes a glass tube 510 and electrode units 520 each functioning as an external electrode.

[92] Each of the electrode units 520 includes a sealing bead glass 521, and a conductive layer 532 is formed at one of outer surface of a lead wire 522 such as a dumet wire formed by coating nickel (Ni) steel with copper (Cu), which has linear expansivity of glass. An area with the conductive layer 523 formed is inserted into a hollow of a body 524 manufactured by powder metallurgy with ferroelectric electrode material having ion and spontaneous polarization. The bodies 524 are sealed by the bead glass 521 with the bodies 524 are inserted into the both ends of the glass tube 510.

[93] It is preferable that each of the bodies 524 is formed in a shape of a barrel having one end closed.

[94] The fluorescent lamp 500 is manufactured as follows.

[95] Referring to FIG. 9, the bodies manufactured by powder metallurgy with ferroelectric electrode material having ion and spontaneous polarization and including composition of the chemical formula 1 or chemical formula 4 are prepared (refer to a diagram A of FIG. 9). It is preferable to manufacture the bodies 524 in a shape of a barrel having closed one end smaller than a diameter of 5mm.

[96] After preparing the bodies 524, the bead glass 521 is formed at the center of the lead wire 522. One side of the lead wire 522 is coated with silver paste as long as a length inserted into the hollow of the body 524. Then, the silver paste coated part of the lead wire 522 is inserted into the tube body 524. After inserting, a firing process is performed at about 400°C(refer to diagrams B and C of FIG. 9). As a result, a half- finished electrode unit 520 having the conductive layer 523 is formed.

[97] After forming the half-finished electrode unit 520, a a predetermined length of a glass tube 510 is prepared by coating fluorescent substance on the inside surface thereof, drying the coated fluorescent substance, and completely removing solvent or organic binder remained therein through a predetermined firing process. Then, the half- finished bodies 524 of the electrode units 520 are inserted into the both ends of the glass tube 510, gas is exhausted from and inserted into the glass tube, and the glass tube 510 is sealed, thereby completely manufacturing the fluorescent lamp 500 (refer to a diagram D of FIG. 9).

[98] In stead of using the ferroelectric electrode material having ion and spontaneous polarization and including composition of the chemical formula 4 or the chemical formula 1, the body 524 can be manufactured through powder metallurgy with ferroelectric electrode material having ion and spontaneous polarization and including composition of the chemical formula 2 or the chemical formula 5, or the chemical formula 3 or the chemical formula 6.

[99] Since the fluorescent lamps according to the first to fourth embodiments uses ferroelectric electrode material having ion and spontaneous polarization and having dielectric constant higher than glass, the fluorescent lamps according to the first to fourth embodiments induce high density wall charge with comparative lower voltage than the conventional fluorescent lamp so as to improve the current density of the lamp. Therefore, the fluorescent lamps according to the first to fourth embodiments provide high brightness.

[100] According to a result of simulations performed by the applicant using a fluorescent lamp having about 8mm of diameter and about 880mm of length and about 800Vrms of driving voltage applied, the fluorescent lamp has about 4w of average power consumption, and about 2000cd/m of average brightness. When about 500Vrms of driving voltage is applied, the fluorescent lamp has about 2OW of average power consumption and about 1200 cd/m of average brightness.

[101] Therefore, light emitting efficiency can be improved about 20% while significantly reducing the lamp driving voltage from 800Vrms to 500Vrms.

[102] The high brightness fluorescent lamp having ferroelectric electrode units having ion and spontaneous polarization according the present invention is not limited to the described embodiments. While to the present invention has been described with respect to certain preferred embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the following claims.

Claims

[1] A fluorescent lamp comprising a glass tube having both ends sealed, an inside surface coasted with fluorescent substance, and charging gas mixed with inert gas and hydrogen gas, and electrode units formed at both end of the glass tube, wherein each of the electrode units includes a body manufactured by power injection molding with ferroelectric electrode material that has polar micro region and perovskite crystal structure which has higher dielectric constant and remanent polarization (over 20μC/cm at lkV/mm) than that of glass material and moreover it has high density for bearing the sputtering phenomena due to collision of electrons and ions with electrode and it has withstand voltage higher than about 1500Vrms/mn.

[2] The fluorescent lamp of claim 1, wherein the body is formed in a hollow shape, a conductive layer is formed on an outer surface of the body, and the body is connected to the glass tube by adhering both ends of the body the glass tube using glass paste for sealing.

[3] The fluorescent lamp of claim 1, wherein the electrode unit includes the body formed in a hollow shape, flanges formed at both ends of the body and inserted and fixed to the glass tube, a ring protrusion formed at a center of outside surface of the body, and a conductive layer formed on the outside surface of the body, and wherein predetermined parts of the body, the flange, and the ring protrusion are inserted into the glass tube and insulated by glass paste for sealing, and the remained part of the ring protrusion is projected out of the glass tube so as to be fixed to the glass tube by glass paste for sealing.

[4] The fluorescent lamp of claim 1, wherein the electrode unit includes the body formed in a hollow shape, a conductive layer with a lead wire fixed to a principal part formed between an inner circumference member and an external circumference member, and sealing glass plates melted and jointed to both ends of the glass tube for sealing both ends of the glass tube, and wherein the lead wire penetrates the sealing glass plate and is fixed at an outer surface of the sealing glass plate by glass paste for sealing, and an inside surface of the sealing glass plate is joined to the internal circumference member and the external circumference member of the body.

[5] The fluorescent lamp of claim 1, wherein the electrode unit includes a conductive layer formed at one side of a lead wire having a bead glass for sealing, an area with the conductive formed is inserted to a hollow of the body, and the body is sealed with both ends of the glass tube by the bead glass with the body inserted into the both ends of the glass tube.

[6] The fluorescent lamp of anyone of claims 1 to 5, wherein the body of the electrode unit is formed by powder metallurgy with ferroelectric electrode material having ion and spontaneous polarization, which is formed by adding about 0 to 10 wt% of addictive including at least one of Y O , CeO , Cr O , and

2 3 2 2 3

Fe O , to composition of a chemical formula:

A [Pb(Sb₀₅Nb₀₅)Oi] - B[Pb(Mn _λ Sb ₂ )O₃} - { 1 - (A + B))Pb(Zr_xTi ^_x)O₃

where 0<A≤0.05mol, 0<B≤0.05mol, and 0.45<x≤lmol.

[7] The fluorescent lamp of anyone of claims 1 to 5, wherein the body of the electrode unit is formed by powder metallurgy with ferroelectric electrode material having ion and spontaneous polarization, which is formed by adding about 10 to 25 wt% of SiO -BaO-CaO-Al O or BeO-CuO-SiO addictive to

2 2 3 2 composition of a chemical formula:

(Ba^_xCa_x)Ti _λ__y__zZr βn _ZO ^ where 0mol≤x≤0.2mol, 0.09mol≤y≤0.14mol, and Omol≤z≤O.lmol. [8] The fluorescent lamp of anyone of claims 1 to 5, wherein the body of the electrode unit is formed by powder metallurgy with ferroelectric electrode material having ion and spontaneous polarization, which is formed by adding about 10 to 25 wt% of SiO -BaO-CaO-Al O or BeO-CuO-SiO addictive to

2 2 3 2 composition of a chemical formula:

( Ce _{! ^x}Sr_x)Zr _yTi _λ __yO ₃ where 0mol≤x<0.2mol, and 0mol≤y<0.03mol.