JP3863332B2 - Metal vapor discharge lamp - Google Patents

Description

【００１９】
この実施例は、
（１）補助電極に隣接した主電極の異常グロー放電電圧の低下と、
（２）紫外線放電管による主電極間の電離と、
（３）グロー管により主電極間に印加されるパルス電圧と
により、始動の可否が決定され、これら三者の相乗効果に始動性が改善されたと考えられる。
【００２０】
また、各抵抗の値を変化させて実験をした結果、以下のことが判明した。
（１）紫外線放電管電流制限抵抗のＲｄが４００ＫΩを越えると、始動パルスが出ていないとき、電源電圧１８０Ｖのみで放電が持続しなくなるため、また、紫外線放電管電流制限抵抗のＲｄが６０ＫΩ未満では、紫外線放電管の寿命がランプ寿命より短くなるため、紫外線放電管電流制限抵抗のＲｄは、６０ＫΩ以上４００ＫΩ以下が望ましい。
（２）ＲａとＲｄの並列接続合成抵抗のＲｏ（Ｒｏ＝（Ｒａ×Ｒｄ）／（Ｒａ＋Ｒｄ））を１５ＫΩ未満とすると始動パルス電圧が低下し、発光管の主電極放電が起こらなくなり、また、ＲａとＲｄの並列接続合成抵抗のＲｏが４５ＫΩを越えると、補助電極の主電極間放電移行への寄与が低下し、いずれも始動電圧が上昇することがわかった。従って、Ｒｏは１５ＫΩ以上４５ＫΩ以下が望ましい。
【００２１】
【発明の効果】
以上のように、この発明の好適な実施の形態によれば、外管内に金属ハロゲン化物が封入され、補助極を持つ発光管とこの発光管を始動させるためのグロー管が配設されたメタルハライドランプにおいて、紫外線を放射する紫外線放電管をその電流制限抵抗（ＲｄＫΩ）を介して発光管に並列に接続してなり、発光管の補助放電電流制限抵抗を（ＲａＫΩ）としたとき、Ｒｄを６０ＫΩ〜４００ＫΩとし、ＲａとＲｄの並列合成抵抗Ｒｏを１５ＫΩ〜４５ＫΩとしたので、発光管製造上の放電空間の放電の容易性のバラツキ及び電極のグロー放電からアーク放電へのバラツキを同時に解決し、始動電圧の低下及び始動時間のバラツキを小さくすることができる。
具体的には、ＡＣ２００Ｖの電源及びチョークコイルバラストを使用して点灯させるメタルハライドランプにおいて、始動電圧を低くでき、始動時間のバラツキを小さくすることができる。
【図面の簡単な説明】
【図１】 本発明の一実施の形態を示す回路図。
【図２】 従来の技術を示す回路図。
【図３】 従来の技術を示す回路図。
【図４】 従来の技術を示す回路図。
【符号の説明】
１ 外管、２ 発光管、３ 金属フィラメント、４ 抵抗、５ 抵抗、６ バイメタルスィッチ、７ 主電極、８ 主電極、９ 補助電極、１０ 安定器、１１ 交流電源、１２ 点灯管、１３ 紫外線放電管、１４ 抵抗。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in starting characteristics of a metal vapor discharge lamp. In particular, the present invention relates to an improvement in starting characteristics of a metal halide lamp.
[0002]
[Prior art]
A metal vapor discharge lamp such as a metal halide lamp has a color rendering property higher than that of a mercury lamp, but has a drawback that a high starting voltage is required. For this reason, it is desired to reduce the starting voltage as much as possible in consideration of safety.
In this regard, as a means for reducing the starting voltage, a technique described in Japanese Patent Application Laid-Open No. 61-216230 is known. In this method, a metal filament coil is provided in the outer tube, and the starting voltage is lowered by irradiating the arc tube with ultraviolet rays emitted from the metal filament coil.
[0003]
2 and 3 are circuit diagrams of a metal halide lamp described in Japanese Patent Application Laid-Open No. 61-216230.
In the figure, 1 is an outer tube made of hard glass, 2 is an arc tube made of quartz glass, 3 is a metal filament for ultraviolet radiation, 4 is a resistor for adjusting the heating power of the metal filament, and 5 is a glow discharge. Resistor 6, bimetal switch 6, main electrode 7 and 8, auxiliary electrode 10, ballast 10, AC power source 11, lighting tube 12, the same principle as the fluorescent lamp lighting tube Generate a pulse voltage.
[0004]
Next, the operation will be described.
When a voltage is applied from the AC power supply 11, a current flows through the metal filament 3 and the metal filament is heated. The heated metal filament 3 emits light and emits ultraviolet rays. Here, since the metal filament 3 is disposed at a position where the emitted ultraviolet light strikes the arc tube 2, the ultraviolet ray is applied to the arc tube.
Then, the auxiliary discharge starts in the arc tube irradiated with ultraviolet rays, and the auxiliary discharge eventually develops into the main discharge, and the arc tube emits light.
Here, the reason why the auxiliary discharge is generated by the irradiation of ultraviolet rays will be described with reference to the description of Japanese Patent Application Laid-Open No. 61-216230.
The reason why the starting voltage of the metal halide lamp is high is considered to be that an impurity gas (for example, HI) generated due to moisture or the like brought into the arc tube by the halide captures free electrons. By the way, when an arc tube is irradiated with ultraviolet rays, electrons are emitted from the electrodes, and ionization of mercury or a rare gas occurs, resulting in an increase in the number of generated free electrons. Furthermore, ultraviolet rays are considered to dissociate impure gas molecules such as HI. As a result, the dissociated impure gas tends to adhere to the tube wall of the arc tube, and therefore the amount of impure gas in the discharge space is reduced. The starting voltage is considered to decrease due to the two effects described above (end of citation).
[0005]
As described above, the prior art makes it possible to start a metal halide lamp with a low starting voltage without using a high voltage pulse due to the action of ultraviolet rays emitted from the metal filament 3.
On the other hand, when there is a lot of impure gas in the arc tube, even if auxiliary discharge occurs, it may not shift to main discharge.
Therefore, in preparation for this case, a lighting tube 12 is provided as shown in FIG. That is, since the ultraviolet radiation by the metal filament 3 is insufficient, a pulse voltage generated with the operation of the lighting tube is added to shift the auxiliary discharge to the main discharge.
[0006]
FIG. 4 shows a metal halide lamp disclosed in Japanese Patent Laid-Open No. 55-130064. Hereinafter, FIG. 4 will be described with reference to the description of Japanese Patent Laid-Open No. 55-130064.
In FIG. 4, a starting series circuit is connected. This series circuit is formed by connecting a lighting tube 17 and an impedance element, for example, a current limiting resistor 4 and a bimetal switch 6 as a normally closed thermoresponsive switch in series. Therefore, this series circuit is interposed so as to be parallel to the arc tube 2 that is lit. When the electrode bimetal is heated by glow discharge, the lighting tube 17 closes between the contacts 17a and 17b, and then the electrode bimetal cools. Therefore, the lighting tube 17 is a known lighting tube that opens the contacts 17a and 17b. Inside, at least one kind of gas such as neon, argon and helium is sealed, and the lighting tube 17 regulates the gas pressure of the sealed gas to 15 Torr or less so as to generate a pulse voltage of 1000 V or more. It is. Further, the bimetal switch 6 is arranged in the outer tube bulb 1 at a position closer to the arc tube 2 side than the lighting tube 17 so as to open by receiving heat from the arc tube 2 side. It has become.
The metal halide lamp based on such a configuration is connected to the mercury lamp ballast 10 and is used for lighting. However, since the ambient temperature is low at the time of starting, the bimetal switch 6 is closed. 6, a current corresponding to the supply voltage from the ballast 10 flows through the resistor 4 and the lighting tube 17. In the lighting tube 17, because of the glow discharge, the electrode bimetal is heated and deformed, and once the contacts 17a and 17b are closed, the electrode bimetal cools and then returns, so that between the contacts 17a and 17b. Is released. A kick voltage associated with the opening operation of the contacts 17a and 17b is applied as a pulse voltage between the electrodes 7 and 8 of the arc tube 2, and a pulse voltage corresponding to the inductance component L of the ballast 10 is generated. Since this is superimposed on the supply voltage, discharge is started between the electrodes 7 and 8 of the arc tube 2.
When the arc tube 2 starts arc discharge, since the discharge voltage in the arc tube 2 at this time is lower than the glow discharge start voltage of the lighting tube 17, the lighting tube 17 starts glow discharge again. There is no. When the discharge of the arc tube 2 becomes stable, the arc tube 2 generates heat, and the bimetal switch 6 disposed close to the arc tube 2 is heated by the arc tube 2 to open a contact. Therefore, in order to maintain the energization circuit to the lighting tube 17, that is, the state in which the series circuit is opened, no pulse voltage is generated even when the lighting tube 17 is closed, and the lamp is extinguished or the resistance is reduced. 4 heat loss is prevented.
[0007]
[Problems to be solved by the invention]
Japanese Patent Application Laid-Open No. Sho 61-216230 applies light (ultraviolet rays), which heats the filament at the time of starting, to the arc tube to facilitate the starting. However, it is mainly possible to suppress the starting variation due to electrode variations. Can not.
Japanese Laid-Open Patent Publication No. 55-130064 discloses a metal halide lamp using a glow tube or a thermally responsive switch (bimetal switch). However, there are variations in electrodes, infilled gas, and mixed impure gas. It is not possible to suppress the variation in startability due to.
That is, since the conventional metal halide lamp has practical variations in production, the starting characteristics vary.
[0008]
In general, when starting a metal halide lamp, a glow discharge occurs between the main electrodes, which increases the discharge current, heats the main electrode, increases the electron emission of the electrode, and the arc applied voltage becomes higher than the abnormal glow discharge voltage. Transition to discharge and the lamp starts. Here, the auxiliary discharge between the auxiliary electrode and the auxiliary electrode adjacent to the auxiliary electrode is only on one side, but it reduces the abnormal glow discharge voltage. Also, ultraviolet rays (especially, Hg resonance lines are effective) in the arc tube create an ionization state that facilitates discharge between the main electrodes of the arc tube. In addition, it is preferable that the lamp application voltage is not a pulse, but it is actually expensive and a starting pulse is used. Some lamps do not start when the voltage applied to the lamp is 200V (AC) alone (the variation is large).
[0009]
Accordingly, an object of the present invention is to improve the starting characteristics of a metal vapor discharge lamp.
[0010]
[Means for Solving the Problems]
A metal vapor discharge lamp according to the present invention includes an outer tube, an arc tube disposed in the outer tube , a pair of main electrodes, and an auxiliary electrode for assisting discharge between the main electrodes, and the outer tube. A normally closed bimetal switch that opens and closes by heat from the arc tube, and is disposed in the outer tube, and is connected in parallel to the arc tube via the normally closed bimetal switch and an ultraviolet discharge tube current limiting resistor. A UV discharge tube that radiates UV light to the outer tube and a starter component that is connected to the series circuit of the UV discharge tube current limiting resistor and the UV discharge tube in parallel via the current limiting resistor to start the arc tube The auxiliary electrode is provided adjacent to one main electrode, and is connected to the other main electrode through an auxiliary discharge current limiting resistor and a normally closed bimetal switch in the outer tube. To do.
[0011]
In addition, the resistance value of the ultraviolet discharge tube current limiting resistor is 60 KΩ or more and 400 KΩ or less.
[0012]
The resistance value of the ultraviolet discharge tube current limiting resistor is Rd, and the resistance value of the parallel connection combined resistance of the ultraviolet discharge tube current limiting resistor and the auxiliary discharge current limiting resistor is Ro (Ro = (Ra × Rd) / (Ra + Rd). ), Ro is set to 15 KΩ or more and 45 KΩ or less.
[0013]
In the metal vapor discharge lamp according to the present invention, the ultraviolet discharge tube is a low-pressure mercury discharge lamp in which at least mercury is sealed, cold cathodes are provided at both ends, and ultraviolet transmissive glass is provided.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a circuit diagram of an electric vapor discharge lamp according to the present embodiment.
1, 2, 4, 5, 6, 7, 8, 9, 10, and 11 in the figure are the same or equivalent parts as in the conventional example.
Here, an example relating to improvement of startability (starting voltage, starting time) of the metal halide lamp is shown.
FIG. 1 shows an arc tube 2 which has a main electrode 7 and an auxiliary electrode 9 at one end and a main electrode 8 at the other end, and is filled with a rare gas such as metal halide, argon gas, and mercury. A glow tube 12 (or a heat responsive switch (not shown) having the same function as the glow tube 12) serving as a starting part for generating a pulse voltage for starting the arc tube 2 is provided, and the auxiliary electrode 9 is The glow tube 12 (or a thermally responsive switch) serving as a starting part is connected in parallel to the arc tube via the current limiting resistor 4 and connected to one end of the arc tube 2 via the auxiliary discharge current limiting resistor 5. A metal halide lamp is shown.
Then, an ultraviolet discharge tube 13 that radiates ultraviolet rays into the outer tube 1 is disposed so that the ultraviolet rays from the ultraviolet discharge tube 13 strike the arc tube 2, and the ultraviolet discharge tube 13 is an ultraviolet discharge tube current limiter. The arc tube is connected in parallel via a resistor 14 and a bimetal switch 6.
[0015]
Further, when the resistance value of the ultraviolet discharge tube current limiting resistor is Rd and the resistance value of the auxiliary discharge current limiting resistor is Ra, Rd is 60 KΩ or more and 400 KΩ or less, and the resistance value Ro ( The value of Ro = (Ra × Rd) / (Ra + Rd)) is set to 15 KΩ or more and 45 KΩ or less.
[0016]
In the metal halide lamp of this embodiment, ultraviolet rays from the ultraviolet discharge tube always keep the discharge space in the arc tube in a stable ionization state, and the parallel connection combined resistance Ro of the auxiliary discharge current limiting resistor Ra and the ultraviolet discharge tube current limiting resistor Rd The selected value promotes a decrease in the discharge start voltage of the electrode due to the discharge between the auxiliary electrode and the main electrode, and acts to supply a start pulse sufficient for the discharge between the main electrodes.
[0017]
The ultraviolet discharge tube 13 is a low-pressure mercury discharge lamp in which at least mercury is enclosed and cold cathodes are provided at both ends.
The ultraviolet discharge tube 13 has an ultraviolet transmission part made of, for example, an ultraviolet transmission glass.
The ultraviolet discharge tube 13 may be entirely formed of ultraviolet transmissive glass, or a portion of the ultraviolet discharge tube 13 may be provided with an ultraviolet transmissive glass portion. In the present embodiment, it is assumed that the entire ultraviolet discharge tube 13 is an ultraviolet transmissive glass.
The ultraviolet discharge tube 13 is disposed at a position where the emitted ultraviolet rays hit the arc tube.
When a voltage is applied to the ultraviolet discharge tube 13, the ultraviolet discharge tube 13 starts to discharge and emits ultraviolet rays. Since the ultraviolet discharge tube 13 is made of ultraviolet transmissive glass, the luminous tube 2 can be irradiated with this ultraviolet ray.
Here, since the ultraviolet discharge tube 13 can emit more ultraviolet rays than a conventional metal filament, the amount of ultraviolet rays irradiated to the arc tube 2 is increased, and the starting voltage can be suppressed lower. In addition, the starting time can be shortened. Thereafter, according to the same principle as in the conventional example, the irradiated ultraviolet light promotes the generation of auxiliary discharge in the arc tube, and the pulse voltage generated by the operation of the glow tube 12 shifts the auxiliary discharge to the main discharge.
Here, the ultraviolet discharge tube 13 is made of ultraviolet transmissive glass having a spectral transmittance of ultraviolet rays of 250 to 260 nm of 10% or more, and the power during glow discharge is 0.5 watts or more. desirable.
In order to ionize mercury atoms, it is necessary to irradiate light with energy slightly higher than the ionization voltage. However, this light has a wavelength close to that of vacuum ultraviolet rays and is not suitable for practical use.
For this reason, as a method of ionizing mercury atoms, a method of causing cumulative ionization by applying light of the lowest excitation level is conceivable. This is because when the light with the lowest excitation level is applied to the mercury atom, excitation of the outermost electron occurs, this electron collides with other atoms continuously, and another electron is excited by this collision. As described above, a phenomenon (accumulation ionization) in which excitation occurs one after another and electrons are finally ionized is used.
In the mercury atom, the wavelength of light at the excitation level is 253.7 nm, and therefore light of 250 to 260 nm is applied to mercury in the arc tube here. Alternatively, light having a wavelength of 185.0 nm may be applied as excitation level light.
[0018]
Examples will be described below.
Scandium iodide, sodium mercury iodide, and rare gas argon 50 Torr were sealed in a quartz arc tube having an inner diameter of 1.95 cm and a length between main electrodes of 4.5 cm. A prototype 400W metal halide lamp with a glow tube, UV discharge tube and UV discharge tube current limiting resistor (Rd = 100KΩ), auxiliary discharge limiting resistor (Ra = 30KΩ), and glow tube current limiting resistor (200KΩ) in the outer tube was produced. . A comparative example without the ultraviolet discharge tube having the same specifications as this example was also prototyped. In addition, a comparative example in which the auxiliary electrode was not used with the same specifications as this example was also prototyped.
In the experiment, a start-up test was performed at a room temperature (25 ° C.) and −10 ° C. with a general choke coil ballast, AC 60 Hz, and a power supply voltage of 180 V. It is necessary to turn on a metal halide lamp with a 200V power supply at commercial frequency. However, it is necessary to turn it on with an inexpensive choke ballast in consideration of the power supply voltage drop, and the experiment was conducted at 180V. It was.
As a result, all of the prototypes in the examples were reliably started.
On the other hand, all of the comparative examples having the same specifications as the example and having no ultraviolet discharge tube started at room temperature, but about 30% of the lamps did not start at -10 ° C.
Moreover, in the comparative example which does not use an auxiliary electrode with the same specification as the example, about 10% at room temperature and 55% at −10 ° C. did not start.

[0019]
This example is
(1) a decrease in the abnormal glow discharge voltage of the main electrode adjacent to the auxiliary electrode;
(2) ionization between main electrodes by an ultraviolet discharge tube;
(3) The possibility of starting is determined by the pulse voltage applied between the main electrodes by the glow tube, and it is considered that the startability is improved by the synergistic effect of these three.
[0020]
In addition, as a result of experiments with different resistance values, the following was found.
(1) If the Rd of the UV discharge tube current limiting resistor exceeds 400 KΩ, the discharge will not be sustained only with the power supply voltage of 180 V when no starting pulse is issued. Also, the Rd of the UV discharge tube current limiting resistor is less than 60 KΩ. Then, since the life of the ultraviolet discharge tube is shorter than that of the lamp, the ultraviolet discharge tube current limiting resistance Rd is preferably 60 KΩ or more and 400 KΩ or less.
(2) When Ro (Ro = (Ra × Rd) / (Ra + Rd)) of the combined resistance of Ra and Rd in parallel is less than 15 KΩ, the starting pulse voltage decreases, and the main electrode discharge of the arc tube does not occur. It has been found that when the combined resistance Ro of Ra and Rd exceeds 45 KΩ, the contribution of the auxiliary electrode to the discharge between the main electrodes decreases, and the starting voltage increases in any case. Therefore, Ro is preferably 15 KΩ or more and 45 KΩ or less.
[0021]
【The invention's effect】
As described above, according to a preferred embodiment of the present invention, a metal halide in which a metal halide is enclosed in an outer tube and an arc tube having an auxiliary electrode and a glow tube for starting the arc tube are disposed. In the lamp, an ultraviolet discharge tube that emits ultraviolet rays is connected in parallel to the arc tube via its current limiting resistor (RdKΩ), and when the auxiliary discharge current limiting resistor of the arc tube is (RaKΩ), Rd is 60 KΩ. and ～400Keiomega, since the parallel combined resistance Ro of the Ra and Rd and 15KΩ~ 4 5KΩ, simultaneously solving the variation from a glow discharge to an arc discharge ease of dispersion and electrodes of the discharge in the discharge space on the arc tube production In addition, it is possible to reduce the decrease in the starting voltage and the variation in the starting time.
Specifically, in a metal halide lamp that is lit using an AC 200V power source and a choke coil ballast, the starting voltage can be lowered and the variation in the starting time can be reduced.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing an embodiment of the present invention.
FIG. 2 is a circuit diagram showing a conventional technique.
FIG. 3 is a circuit diagram showing a conventional technique.
FIG. 4 is a circuit diagram showing a conventional technique.
[Explanation of symbols]
1 outer tube, 2 arc tube, 3 metal filament, 4 resistor, 5 resistor, 6 bimetal switch, 7 main electrode, 8 main electrode, 9 auxiliary electrode, 10 ballast, 11 AC power source, 12 lighting tube, 13 UV discharge Tube, 14 resistance.

Claims (4)

An outer tube,
An arc tube disposed in the outer tube and having a pair of main electrodes and an auxiliary electrode for assisting discharge between the main electrodes ;
A normally closed bimetal switch disposed in the outer tube and opened and closed by heat from the arc tube;
An ultraviolet discharge tube disposed in the outer tube, connected in parallel to the arc tube via the normally closed bimetal switch, and an ultraviolet discharge tube current limiting resistor, and emitting an ultraviolet ray to the arc tube;
The auxiliary electrode, which is disposed in the outer tube, is connected in parallel to the series circuit of the ultraviolet discharge tube current limiting resistor and the ultraviolet discharge tube via a current limiting resistor, and starts the arc tube. Is provided adjacent to the one main electrode, and is connected to the other main electrode through the auxiliary discharge current limiting resistor and the normally closed bimetal switch in the outer tube. Steam discharge lamp. The metal vapor discharge lamp according to claim 1, wherein a resistance value of the ultraviolet discharge tube current limiting resistor is set to 60 KΩ or more and 400 KΩ or less. The resistance value of the ultraviolet discharge tube current limiting resistor and Rd, the resistance of the parallel connection combined resistance of the UV discharge tube current limiting resistor and the auxiliary discharge current limiting resistor Ro (Ro = (Ra × Rd ) / (Ra + Rd)) The metal vapor discharge lamp according to claim 2, wherein Ro is set to 15 KΩ or more and 45 KΩ or less.   2. The metal vapor discharge lamp according to claim 1, wherein the ultraviolet discharge tube is a low-pressure mercury discharge lamp in which at least mercury is sealed, cold cathodes are provided at both ends, and ultraviolet transmissive glass is provided.

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