EP0670588A1 - Metallhalogenidlampe - Google Patents
Metallhalogenidlampe Download PDFInfo
- Publication number
- EP0670588A1 EP0670588A1 EP94301523A EP94301523A EP0670588A1 EP 0670588 A1 EP0670588 A1 EP 0670588A1 EP 94301523 A EP94301523 A EP 94301523A EP 94301523 A EP94301523 A EP 94301523A EP 0670588 A1 EP0670588 A1 EP 0670588A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- moles
- halide lamp
- metal
- bromine
- iodine
- 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.)
- Granted
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J61/00—Gas-discharge or vapour-discharge lamps
- H01J61/02—Details
- H01J61/12—Selection of substances for gas fillings; Specified operating pressure or temperature
- H01J61/18—Selection of substances for gas fillings; Specified operating pressure or temperature having a metallic vapour as the principal constituent
- H01J61/20—Selection of substances for gas fillings; Specified operating pressure or temperature having a metallic vapour as the principal constituent mercury vapour
Definitions
- the present invention generally relates to a metal halide lamp and, more particularly, to contents which are contained in a hermetically sealed tube of a metal halide lamp.
- a metal halide lamp is a lamp in which a metal halide is added in a sealed tube, in which mercury vapor is contained at a high pressure, to improve the luminous efficacy and color rending properties, and is widely used for general illumination.
- a conventional metal halide lamp is fabricated by charging, in a light-transmitting quartz tube, an inert gas, e.g., argon (Ar), at least one kind of halide (LnX2 or LnX3: where Ln is a rare earth metal, e.g., scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium
- tungsten (W) as the base material of electrodes is liberated by sputtering during use, and free tungsten reacts with silicon dioxide (SiO2) as a constituent component of the sealed tube to deposit on the inner wall surface of the sealed tube, thereby blackening the tube wall within a short period of time. Blackening of the tube wall decreases the luminous efficacy and lumen maintenance factor. When the lumen maintenance factor decreases to about 70%, the metal halide lamp becomes inappropriate for practical use.
- the present invention has been made in view of the above situation, and the object of the present invention is to provide a long-life metal halide lamp which can prevent blackening of the tube wall.
- a metal halide lamp comprising a sealed tube, a pair of electrodes made of tungsten as a base material and arranged to oppose each other in the sealed tube, and contents of the sealed tube and including an inert gas, mercury, a rare earth metal, bromine, and iodine, wherein the total number of moles of bromine and iodine is in excess of the number of moles of the rare earth metal.
- the total number of moles of bromine and iodine must be in excess of the total number of moles of the rare earth metals.
- Excess here means that when bromine and iodine react with all the rare earth metals, bromine or iodine that does not react with the rare earth metals remains. Accordingly, even when tungsten is emitted from the electrodes during electric discharge, it can be captured by iodine or bromine.
- Fig. 1 is a view of a metal halide lamp according to an embodiment of the present invention, and shows the principle of function of the present invention.
- This metal halide lamp has a transparent quartz sealed tube and a pair of electrodes using tungsten as the base material. The respective electrodes are mounted on the sealed tube with hermetically passing through the wall surface of the sealed tube. The inner end portions of these electrodes are opposed to each other.
- Argon (Ar), a rare earth metal (Ln), mercury (Hg), cesium (Cs), iodine (I), and bromine (Br) are contained in the sealed tube.
- these contents are charged in the tube in the form of atoms or compounds. More specifically, bromides of the rare earth metal (LnBr2 and LnBr3), mercury iodide (HgI2), cesium iodide (CsI), argon gas, and mercury are charged in the tube during the manufacture.
- the amounts of bromine and iodine are in excess of the amount of rare earth metals.
- Fig. 1 when arc discharge is started between a pair of opposed electrodes 2 and 3 which are made of tungsten as the base material, mainly in a high-temperature (2,000°C or more) area near the electrodes 2 and 3, most of the contents are ionized. Tungsten of the electrodes 2 and 3 is also emitted from the electrodes 2 and 3 by sputtering and is ionized.
- bromine or iodine are recombined with cesium, and bromine or iodine are also recombined with rare earth metal. Further, mercury and tungsten are set in the atomic state. The excesses of bromine and iodine which are not recombined with the rare earth metal and cesium are also set in the atomic state. Since bromine has a higher reactivity than iodine, bromine is combined with cesium and rare earth metal before iodine is combined therewith. Therefore, in this medium-temperature area, most of the halogens in the atomic state are iodine.
- a medium-temperature a range of 1,000°C or more to less than 2,000°C
- tungsten tends to be combined with iodine. Unlike bromine, even when iodine is combined with mercury, it is quickly separated from mercury. When the amounts of free tungsten and iodine are sufficient with respect to each other, all tungsten atoms are captured by halogens, mainly iodine. Therefore, tungsten will not react with silicon dioxide which is an element constituting the sealed tube. Thereafter, the materials produced in the low-temperature area are circulated in a cycle indicated by arrows due to heat convection.
- Tungsten iodides WI2, WI3 and WI4
- halides of rare earth metal LnX2 and LnX3
- silicon dioxide the low-temperature area
- these products do not highly react with silicon dioxide, a long period of time is required until the tube wall is blackened to such a degree that the sealed tube is inappropriate for practical use.
- free tungsten can be captured mainly by iodine and set in the halogen cycle, so that the effect of suppressing blackening of the tube wall is much enhanced.
- a preferable condition of "excess" described above is expressed by a relation of numbers of moles as follows: [M(Br) + M(I)]/M(Ln) > 3 where M(Br) is the number of moles of bromine atoms, M(I) is the number of moles of iodine atoms, and M(Ln) is the number of moles of rare earth metal atoms.
- Fig. 2 is a view showing the principle of a case wherein bromine is not added at all and only an excess of iodine is charged in a sealed tube.
- iodine is combined with the rare earth metal, cesium and tungsten.
- the iodide of the rare earth metal is combined less than the bromide of the rare earth metal, substitution reaction of the rare earth metal with silicon dioxide of the sealed tube often occurs.
- the rare earth metal tends to deposit on the inner wall surface of the sealed tube, thereby decreasing the service life when compared to a case wherein bromine is contained in the sealed tube.
- M(Br)/M(Ln) ⁇ 1 The upper limit of the above value is preferably 3 from the results of various experiments. More specifically, 3 ⁇ M(Br)/M(Ln) ⁇ 1 Examples of the present invention will be described.
- a rugby-ball like spherical quartz sealed tube having a major axis of 25 mm, a minor axis of 21 mm, an internal volume of 3.2 cc, and an interelectrode distance of 7 mm was used.
- Argon gas was contained as an initiating inert gas, and the pressure in the sealed tube was set to 50 to 300 torr (6.65 to 39.9 kPa).
- the electrodes were made of tungsten as the base material. Cesium was contained to prevent flickering of the lamp.
- the present invention is not intended to be limited to the above-mentioned size or pressure, etc.
- Table 1 indicates the compositions, electrical characteristics, optical characteristics, and the like of the contents (excluding argon) of Examples 1 to 9 according to the present invention.
- two or more kinds of rare earth metals appropriately selected from dysprosium (Dy), holmium (Ho), thulium (Tm), neodymium (Nd) and erbium (Er); an alkali metal, i.e., cesium (Cs); iodine (I); bromine (Br); and mercury (Hg) were contained in the sealed tube to satisfy the relations (2) and (4).
- the rare earth metals and the alkali metal were charged in the form of iodides or bromides in Examples 1 to 9.
- the electrical characteristics indicate the initial value
- the lumen maintenance factor of the optical characteristics is a proportion of the value of the luminous flux at a lapse of a predetermined period of time with respect to the initial value of the luminous flux at the central area on the screen when light was projected from the metal halide lamp of each example which is mounted in an overhead projector.
- x represented a case wherein the lumen maintenance factor was less than 70% before the lapse of 48 hours since the start of light emission
- ⁇ represented a case wherein the lumen maintenance factor was 70% or more at the lapse of 48 hours but was less than 70% at the lapse of 500 hours
- o represented a case wherein the lumen maintenance factor was between 70% or more and less than 80% at the lapse of 500 hours
- o represented a case wherein the lumen maintenance factor was 80% or more at the lapse of 500 hours.
- Example 1 As is understood from Table 1, it is apparent that in any of Examples 1 to 9, a high lumen maintenance factor was maintained over a long period of time, and blackening of the tube wall was prevented. Especially, in Example 1 wherein 10.75 x 10 ⁇ 6 mole of rare earth metals (dysprosium, holmium, and thulium), 0.51 x 10 ⁇ 6 mole of cesium, 32.76 x 10 ⁇ 6 mole of iodine, and 27.75 x 10 ⁇ 6 mole of bromine were contained in the sealed tube, the lumen maintenance factor was maintained at 90% over 1,000 hours and 85% after 1,630 hours, thereby obtaining an excellent result.
- rare earth metals disprosium, holmium, and thulium
- the preferable condition is as follows: 3 ⁇ M(Br)/M(Ln) ⁇ 2, and [M(Br) + M(I) - M(NA)]/M(Ln) > 4.5
- the further preferable condition is as follows: 2.95 ⁇ M(Br)/M(Ln) ⁇ 2.2, and [M(Br) + M(I) - M(NA)]/M(Ln) > 4.6
- the value of [M(Br) + M(I) - M(NA)]/M(Ln) may be more than 3.
- Samples 1 to 4 of Table 2 exhibit the performance of each metal halide lamp in which the composition of the contents does not satisfy conditions (2) and (4).
- Samples 2 and 3 show cases of conventional metal halide lamps wherein experiments were conducted without charging bromine.
- Sample 4 shows a case of a metal halide lamp in which bromine was charged together with iodine. In Sample 4, however, the relationship between numbers of moles does not satisfy the above conditions. It is apparent that in these Samples 2 and 4 the lumen maintenance factors become less than 70% after 48 hours, so that blackening of the tube wall occurs in an early period.
- Fig. 3 is a graph showing service life data of Example 1 of the present invention and that of Sample 2. The excellence of the present invention can be clearly recognized from Fig. 3.
- a ceramic sealed tube mainly a light-transmitting alumina (Al2O3) tube
- quartz (SiO2) sealed tube because the mechanism of blackening of the alumina tube and preventing it is substantially similar to the one for the quartz tube.
- a sealed tube which is made of a synthetic transparent glass material comprising quartz or alumina doped with a metal oxide, e.g., ZrO2 or TiO2.
- the sealed tube need not to be completely transparent but one, e.g., made of frosted glass, that can partly transmit light therethrough may be used instead.
- the inert gas in the sealed tube is not limited to argon gas, but other gases, e.g., helium, neon, krypton, xenon, or radon gas, can be used.
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4256287A JPH06111769A (ja) | 1992-09-25 | 1992-09-25 | メタルハライドランプ |
DE1994603190 DE69403190T2 (de) | 1994-03-02 | 1994-03-02 | Metallhalogenidlampe |
EP94301523A EP0670588B1 (de) | 1992-09-25 | 1994-03-02 | Metallhalogenidlampe |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4256287A JPH06111769A (ja) | 1992-09-25 | 1992-09-25 | メタルハライドランプ |
EP94301523A EP0670588B1 (de) | 1992-09-25 | 1994-03-02 | Metallhalogenidlampe |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0670588A1 true EP0670588A1 (de) | 1995-09-06 |
EP0670588B1 EP0670588B1 (de) | 1997-05-14 |
Family
ID=26136968
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP94301523A Expired - Lifetime EP0670588B1 (de) | 1992-09-25 | 1994-03-02 | Metallhalogenidlampe |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0670588B1 (de) |
JP (1) | JPH06111769A (de) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5866981A (en) * | 1995-08-11 | 1999-02-02 | Matsushita Electric Works, Ltd. | Electrodeless discharge lamp with rare earth metal halides and halogen cycle promoting substance |
CN1118855C (zh) * | 1997-04-03 | 2003-08-20 | 松下电器产业株式会社 | 金属卤化物灯 |
WO2009075943A2 (en) * | 2007-12-06 | 2009-06-18 | General Electric Company | Metal halide lamp with halogen-promoted wall cleaning cycle |
WO2013096067A1 (en) * | 2011-12-19 | 2013-06-27 | General Electric Company | High intensity discharge lamp with improved startability and performance |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5532338A (en) * | 1978-08-29 | 1980-03-07 | Mitsubishi Electric Corp | Metal halide lamp |
EP0169510A2 (de) * | 1984-07-24 | 1986-01-29 | Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH | Metallhalogenid-Hochdruckentladungslampe |
DE3512757A1 (de) * | 1985-04-10 | 1986-10-23 | Philips Patentverwaltung Gmbh, 2000 Hamburg | Metallhalogenid-hochdruckgasentladungslampe |
EP0477668A1 (de) * | 1990-09-24 | 1992-04-01 | Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH | Metallhalogenid-Hochdruckentladungslampe |
-
1992
- 1992-09-25 JP JP4256287A patent/JPH06111769A/ja active Pending
-
1994
- 1994-03-02 EP EP94301523A patent/EP0670588B1/de not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5532338A (en) * | 1978-08-29 | 1980-03-07 | Mitsubishi Electric Corp | Metal halide lamp |
EP0169510A2 (de) * | 1984-07-24 | 1986-01-29 | Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH | Metallhalogenid-Hochdruckentladungslampe |
DE3512757A1 (de) * | 1985-04-10 | 1986-10-23 | Philips Patentverwaltung Gmbh, 2000 Hamburg | Metallhalogenid-hochdruckgasentladungslampe |
EP0477668A1 (de) * | 1990-09-24 | 1992-04-01 | Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH | Metallhalogenid-Hochdruckentladungslampe |
Non-Patent Citations (1)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 4, no. 63 (E - 010) 13 May 1980 (1980-05-13) * |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5866981A (en) * | 1995-08-11 | 1999-02-02 | Matsushita Electric Works, Ltd. | Electrodeless discharge lamp with rare earth metal halides and halogen cycle promoting substance |
DE19632220B4 (de) * | 1995-08-11 | 2005-07-28 | Matsushita Electric Works, Ltd., Kadoma | Elektrodenlose Entladungslampe |
CN1118855C (zh) * | 1997-04-03 | 2003-08-20 | 松下电器产业株式会社 | 金属卤化物灯 |
WO2009075943A2 (en) * | 2007-12-06 | 2009-06-18 | General Electric Company | Metal halide lamp with halogen-promoted wall cleaning cycle |
WO2009075943A3 (en) * | 2007-12-06 | 2009-08-27 | General Electric Company | Metal halide lamp with halogen-promoted wall cleaning cycle |
WO2013096067A1 (en) * | 2011-12-19 | 2013-06-27 | General Electric Company | High intensity discharge lamp with improved startability and performance |
US8482198B1 (en) | 2011-12-19 | 2013-07-09 | General Electric Company | High intensity discharge lamp with improved startability and performance |
Also Published As
Publication number | Publication date |
---|---|
EP0670588B1 (de) | 1997-05-14 |
JPH06111769A (ja) | 1994-04-22 |
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