JP2007095598A - Discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp which is capable of keeping the partial pressure of hydrogen in an outer bulb low through the lifetime period from the beginning of lighting by effectively absorbing hydrogen generated in the outer bulb when the discharge lamp mounting an arc tube in the outer bulb is turned on. <P>SOLUTION: This discharge lamp mounting an arc tube 3 in an outer bulb 2 comprises: a main getter 13 which is activated promptly by heat generated when a lamp is turned on, and effects hydrogen absorbing performance from the beginning of lighting; and an auxiliary getter 14 which absorbs hydrogen released again from the main getter 13 by overheat of the main getter 13, and suppresses the partial pressure increase of hydrogen in the outer bulb 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a discharge lamp in which a getter that absorbs an impure gas is provided in an outer sphere that houses and arranges an arc tube.

A metal vapor discharge lamp in which an arc tube is accommodated in a vacuum outer sphere or in an outer sphere filled with an inert gas is caused by impure gas generated from members disposed in the outer sphere by heat during lighting. In order to prevent the lamp characteristics from being damaged, a getter that absorbs the impure gas is provided in the outer sphere. There are two types of getters: an evaporative getter that heats at high frequency for activation and evaporates the getter component, and a non-evaporable getter that activates without evaporating the getter component. Barium getters that can exhibit gas absorption performance are widely used, and zirconium / aluminum getters that are excellent in hydrogen absorption performance are widely used as the latter.

The applicant of the present application also provides a discharge lamp using a combination of a barium getter capable of exhibiting impure gas absorption performance for a long time and a zirconium / aluminum getter excellent in hydrogen absorption performance (see Patent Document 1). . However, for an inert gas sealed type discharge lamp in which nitrogen gas is sealed in the outer sphere, when the getter provided in the outer sphere is heated at high frequency, the getter component is nitrided by the high heat and absorbs impure gas. Therefore, an evaporative getter that evaporates and activates the getter component by high-frequency heating, such as a barium getter, cannot be used, so a barium peroxide getter is used instead of the barium getter, and the barium peroxide getter and zirconium Proposals have also been made to use an aluminum getter together (see Patent Document 2).

Also, the evaporation type barium getter has a problem that the getter component evaporated by high-frequency heating adheres to the inner surface of the outer sphere to form a film, and the film blocks the light emitted from the arc tube and reduces the luminous flux. Therefore, there are many discharge lamps that use only non-evaporable zirconium / aluminum getters without using them. For vacuum type discharge lamps in which inert gas is not sealed in the outer sphere, it is possible to activate the getter provided in the outer sphere by high-frequency heating. Since the metal material forming other members such as the arc tube post provided is also heated to a high temperature, the metal material may evaporate and the inside of the outer sphere may be contaminated. Moreover, since the high frequency heating apparatus is very expensive, there is a problem that the equipment cost increases.

By the way, a commercially available zirconium / aluminum getter is formed of a tablet-type or tape-type (band-type) zirconium-aluminum alloy (Zr: 84 wt%, Al: 16 wt%) whose surface is protected by an oxide film. The activation variables are 900 ° C. for 30 seconds, 800 ° C. for 5 minutes, and 750 ° C. for 25 to 30 minutes. That is, even when heated to 750 ° C. by high-frequency heating, it takes 25 to 30 minutes for the oxide film protecting the surface to be removed and become 100% activated, and 150 ° C. from that time. At a low 600 ° C., only about 30% is activated even when heated for 30 minutes. Moreover, it takes several tens of hours to several hundreds of hours until a moderate hydrogen absorption effect can be obtained if it is activated by heat generated by lighting of the lamp (generally around 400 ° C.) regardless of high-frequency heating. It will be.

Therefore, if the zirconium / aluminum getter in the outer sphere is not heated in advance during the lamp manufacturing process, the outer bulb is The hydrogen generated in the lamp will not be absorbed indefinitely, and the hydrogen concentration and hydrogen partial pressure in the outer bulb will increase and the lamp characteristics will change. In the manufacturing process, it is troublesome to perform a process of activating the getter provided in the outer sphere by high-frequency heating.

In addition, as described above, a lamp in which nitrogen gas is sealed in the outer sphere may activate the getter by high-frequency heating because the getter component provided in the outer sphere may be nitrided when heated at a high temperature. I can't. Therefore, a zirconium-cobalt-rare earth alloy (Zr: 75 to 85% by weight, Co: 10 to 20% by weight, Ce · La ··) that can be activated by heat during lamp operation without using high frequency heating. Nd: 1 to 10% by weight) has been proposed (see Patent Document 3).

However, commercial products of zirconium / cobalt / rare earth getters have an operating temperature of 300 to 350 ° C., and can be activated in about 2 hours at 350 ° C. However, recent lamps and lighting fixtures to be combined with the lamps Use the getter at an appropriate operating temperature because it tends to be more compact with emphasis on design and construction, and the temperature tends to increase when the lamp is turned on. In such a situation, the temperature when the lamp is used may reach 500 to 600 ° C. Zirconium / cobalt / rare earth getters have a higher hydrogen absorption rate than other types of getters, but when the temperature exceeds 500 ° C., the reversibility of resorbing absorbed hydrogen becomes significant. When used in a lamp having a high temperature exceeding 500 ° C., there is a problem in that the hydrogen partial pressure in the outer sphere increases and lamp characteristics are impaired.
Japanese Patent No. 297217 JP 2004-139850 A JP-T-2004-524671

The present invention provides a shipping inspection in which the manufactured lamp is tested to determine whether the lamp characteristics are acceptable or not, without performing the troublesome processing of activating the getter provided in the outer sphere by high-frequency heating during the manufacturing process of the lamp. When it is performed, the getter function that absorbs hydrogen generated in the outer sphere is quickly activated by the heat generated by the lighting of the lamp, so that the shipment inspection of the lamp can be performed accurately and efficiently, and the lamp It is a technical problem to prevent the lamp characteristics from being impaired by increasing the hydrogen partial pressure in the outer sphere even when the lighting temperature is higher than 500 ° C.

In order to solve the above-mentioned problems, the present invention provides a discharge lamp provided with a non-evaporable getter that absorbs an impure gas in an outer sphere that houses and arranges an arc tube. A main getter that can be activated quickly by the heat generated by the heat to exert hydrogen absorption performance from the beginning of its lighting, and when the hydrogen is re-released from the main getter due to overheating of the main getter, An auxiliary getter that suppresses an increase in the hydrogen partial pressure is provided.

In the discharge lamp according to the present invention, the main getter that is rapidly activated by the heat when the lamp is lit exhibits the hydrogen absorption performance from the beginning of lighting. When the main getter is overheated and hydrogen absorbed by the main getter is re-released, the re-released hydrogen is absorbed by the auxiliary getter and the increase in the hydrogen partial pressure in the outer sphere is suppressed. The

Therefore, the main getter that is quickly activated by the heat when the lamp is turned on does not need to perform the troublesome process of activating the getter provided in the outer sphere by high-frequency heating during the lamp manufacturing process. Since the hydrogen absorption performance is exhibited from the beginning and the hydrogen partial pressure in the outer sphere is kept low, the manufactured lamp can be inspected with high accuracy and efficiently. Moreover, even when the lamp is downsized or used in combination with a lighting fixture, the temperature at the time of lamp lighting is remarkably increased, the main getter is overheated, and hydrogen is re-released from the main getter. Since the hydrogen released from the main getter is absorbed by the auxiliary getter and the increase in the hydrogen partial pressure in the outer sphere is suppressed, the lamp characteristics are excellently maintained from the beginning of lamp operation to the lifetime. effective.

BEST MODE FOR CARRYING OUT THE INVENTION The best embodiment of a discharge lamp according to the present invention is a zirconium, cobalt, rare earth that can be quickly activated by heat when the lamp is turned on to exhibit hydrogen absorption performance in an outer bulb that houses and arranges the arc tube. The main getter made of an alloy exhibits a hydrogen absorption performance even at a high temperature exceeding 500 ° C., where the activation temperature is relatively higher than that of the main getter and hydrogen re-release from the main getter becomes remarkable. An auxiliary getter made of a zirconium-aluminum alloy capable of absorbing hydrogen re-released from the getter is provided.

These getters are arranged on one end side of the arc tube so as not to block the light emitted from the arc tube as much as possible, and are fixed to the arc tube column supporting the arc tube or a member attached to the column. ing. In addition, the main getter made of zirconium, cobalt, and rare earth alloy is activated in about 10 minutes when heated to a temperature close to 500 ° C., so that it can be quickly heated to near 500 ° C. by the heat of the lamp. It arrange | positions close to the arc_tube | light_emitting_tube used as a heating source, or arrange | positions so that it may face an arc tube from the one end side of an arc_tube | light_emitting_tube. On the other hand, the auxiliary getter made of zirconium-aluminum alloy takes a relatively long time to be activated by the heat of the lamp, but after activation, the lower the temperature, the better the hydrogen absorption and the hydrogen partial pressure. Since it can be kept low, it is arranged in a place where the temperature when the lamp is lit is low so as not to face the arc tube.

FIG. 1 is a longitudinal sectional view showing a first embodiment of a discharge lamp according to the present invention, and FIG. 2 is a relationship between the temperature of the main getter / auxiliary getter provided in the outer sphere of the discharge lamp and the hydrogen partial pressure in the outer sphere. It is a graph which shows.

The discharge lamp of this example is a vacuum type metal halide lamp in which an arc tube 3 and an arc tube support 4 that supports the arc tube 3 in a fixed position are accommodated in an outer bulb 2 having a base 1. The arc tube 3 is formed of a translucent ceramic, and a pair of electrode systems are inserted into capillaries 5 and 6 provided at both ends thereof. The arc tube support 4 supports both ends of the arc tube 3 with a hook-shaped column portion 8 and a short column portion 9 erected on a stem 7 provided on the base 1 side. , 9 is formed of a nickel-plated iron wire having a wire diameter of about 1.6 mm, and forms part of a feeding circuit that supplies lamp power to the electrode systems in the capillaries 5 and 6 provided at both ends of the arc tube 3. Yes. Further, the arc tube 3 is welded directly to the column portions 8 and 9 of the arc tube support 4 by external leads 10 and 11 protruding from the ends of the capillaries 5 and 6 provided at both ends thereof, or nickel. It is supported by the arc tube support 4 by welding via a ribbon wire 12 or the like.

The vacuum outer sphere 2 absorbs hydrogen generated from the arc tube support 4 made of nickel-plated iron wire, the nickel ribbon wire 12, the external leads 10, 11 and the like when the lamp is turned on, and the outer sphere 2 2 is provided with a main getter 13 and an auxiliary getter 14 which are non-evaporable getters that are activated by heat when the lamp is turned on and exhibit hydrogen absorption performance. .

The main getter 13 is a non-evaporable getter that can exhibit hydrogen absorption performance from the beginning of lighting of the lamp. For example, a tablet type zirconium / cobalt / rare earth activated in about 10 minutes when heated to a high temperature close to 500 ° C. A zirconium-cobalt-rare earth getter (manufactured by SAES: product number St787) in which a getter body 15 made of an alloy is attached to a metal tab 16 is used. In addition, the auxiliary getter 14 has a getter body 17 made of a tablet-type zirconium-aluminum alloy that takes 25 to 30 minutes to be activated even when heated to a high temperature of 750 ° C., for example, and is attached to a metal tab 18. Zirconium aluminum getter (manufactured by SAES: product number St101) is used.

When only one of the main getter 13 and the auxiliary getter 14 is provided in the outer sphere 2 and the correlation between the heating temperature of each getter and the hydrogen partial pressure in the outer sphere 2 is verified, the graph of FIG. Thus, when only the main getter 13 is provided, when the temperature of the getter 13 exceeds 500 ° C., the hydrogen partial pressure in the outer sphere 2 rapidly increases, whereas when only the auxiliary getter 14 is provided. Even if the temperature of the getter 14 exceeds 500 ° C., the hydrogen partial pressure in the outer sphere 2 does not increase, and after exceeding 700 ° C., the hydrogen partial pressure in the outer sphere 2 starts to increase. That is, when the temperature of the main getter 13 exceeds 500 ° C., the re-release of hydrogen becomes remarkable. However, the auxiliary getter 14 has a higher hydrogen absorption capacity than the discharge capacity until it exceeds 700 ° C.

Therefore, when the discharge lamp of FIG. 1 is used in combination with a lighting fixture, the main getter 13 and the auxiliary getter 14 provided in the outer sphere 2 are heated to a high temperature of about 500 ° C. by the heat of the lamp. In the case of heating, the main getter 13 is activated quickly and exhibits hydrogen absorption performance from the beginning of lamp operation, and hydrogen re-released from the getter 13 due to overheating of the main getter 13 is supplementary getter. 14, the increase of the hydrogen partial pressure in the outer sphere 2 is suppressed. That is, the hydrogen partial pressure in the outer sphere 2 can be kept low by the main getter 13 and the auxiliary getter 14 from the initial lighting of the lamp to the lifetime. The main getter 13 and the auxiliary getter 14 shown in FIG. 1 are arranged at one end side of the arc tube 3 supported by the column portion 8 of the arc tube support 4 so as not to block the light emitted from the arc tube 3 as much as possible. It arrange | positions so that it may not face the arc tube 3, and it fixes by welding each metal tabs 16 and 18 with respect to the pillar part 8. FIG.

FIG. 3 is a partial sectional view showing a second embodiment of the discharge lamp according to the present invention.
In the discharge lamp of this example, the main getter 13 made of zirconium, cobalt, and a rare earth getter is disposed closer to the arc tube 3 than the position shown in FIG. 1 and faces the arc tube 3 from one end side of the arc tube 3. 1 is different from the discharge lamp of FIG. 1 in other points, and the other configuration is the same as that of the lamp of FIG.

When the inventor prototyped a metal halide lamp with a rated lamp power of 150 W having the configuration as shown in FIG. 1 and measured the temperatures of the main getter 13 and the auxiliary getter 14 when the lamp was barely lit, the temperatures were about It was 410 ° C. That is, the temperature of both getters 13 and 14 when the 150W metal halide lamp in which the main getter 13 and the auxiliary getter 14 are arranged as shown in FIG. there were. Therefore, the main getter 13 using a zirconium / cobalt / rare earth getter, which is said to require two hours for activation at 350 ° C., requires at least several tens of minutes to be activated after the lamp is turned on. As a result, it is not possible to efficiently perform a shipping inspection in a short time to test the manufactured lamp and determine whether the lamp characteristics are acceptable.

Therefore, the discharge lamp of FIG. 3 is arranged so that the main getter 13 made of zirconium, cobalt, and rare earth getter is closer to the arc tube 3 than the position shown in FIG. 1 and faces the arc tube 3 from one end side of the arc tube 3. Thus, it is devised to be heated to a temperature close to 500 ° C. when it is lit naked. Actually, when a 150W metal halide lamp with the main getter 13 arranged as shown in FIG. 3 is prototyped and lit, the temperature when the main getter 13 is barely lit becomes 502 ° C. that can be activated in about 10 minutes. It was done.

FIG. 4 is a partial sectional view showing a third embodiment of the discharge lamp according to the present invention.
The discharge lamp of this example is provided with a main getter 13 made of zirconium / cobalt / rare earth getter and an auxiliary getter 14 made of zirconium / aluminum getter in the outer sphere 2 in the same manner as the discharge lamp of FIG. The getter 13 is disposed so as to be close to the arc tube 3 and face the arc tube 3 from one end side of the arc tube 3, and the difference from the discharge lamp of FIG. 3 is that the auxiliary getter 14 is different from that of FIG. Also, it is located away from the arc tube 3 at a place where the temperature when the lamp is lit is low.

When the 150 W metal halide lamp of FIG. 3 prototyped by the present inventor is used in combination with a lighting fixture, the temperatures of the main getter 13 and auxiliary getter 14 arranged as shown in FIG. And 520 ° C. That is, when the lamp of FIG. 3 is lit in the lighting fixture, the main getter 13 disposed so as to face the arc tube 3 and face the arc tube 3 rises to near 600 ° C. The re-release of hydrogen from the main getter 13 becomes significant. On the other hand, the auxiliary getter 14 exhibits a hydrogen absorption performance even at a high temperature exceeding 500 ° C., absorbs hydrogen re-released from the main getter 13, and acts to keep the hydrogen partial pressure in the outer sphere 2 low.

However, since it takes a relatively long time for the auxiliary getter 14 to be activated by the heat of the lamp, it is desirable to arrange the auxiliary getter 14 in a place where the temperature is high in order to promote the activation, but the optimum operating temperature is After activation, the lower the temperature, the higher the hydrogen absorption rate and the greater the effect of suppressing the hydrogen partial pressure, so that the auxiliary getter 14 in FIG. 4 is turned on in the lighting fixture. It is arranged away from the arc tube 3 than the position of FIG. 3 where the temperature is 520 ° C., and is arranged not to face the arc tube 3 in a place where the temperature when the lamp is lit is low, so that the hydrogen absorption performance can be maximized. It has become.

The main getter 13 and the auxiliary getter 14 of Examples 1 to 3 have their getter bodies 15 and 17 formed in a tablet shape, but are not limited to this, and are formed in a tape shape (band shape). It may be a thing.

Further, even when the lamp is used in combination with a lighting device, if the temperature of the auxiliary getter 14 arranged as shown in FIG. 3 or FIG. 4 does not exceed 500 ° C., the auxiliary getter 14 is used as the main getter 14. Even if the same kind of zirconium / cobalt / rare earth getter as that of No. 13 is used, substantially the same effect as the above embodiment can be obtained.

That is, depending on the size of the lamp and the lamp power, the auxiliary getter 14 may be placed in a place where the temperature does not reach 500 ° C. or higher. In such a case, both the main getter 13 and the auxiliary getter 14 use zirconium / cobalt / rare earth getters to bring the main getter 13 close to the arc tube 3 or one end of the arc tube 3 as shown in FIGS. It is arranged so as to face the arc tube 3 from the side so that it can be heated to a high temperature that can be activated in a short time, and the auxiliary getter 14 is arranged in a place where the temperature is lower than that of the main getter 13, and 500 ° C. By preventing the hydrogen from being re-released from the main getter 13 by the auxiliary getter 14, it is possible to keep the hydrogen partial pressure low from the beginning of lamp operation to the lifetime.

If a zirconium / aluminum getter is provided instead of the main getter 13 shown in FIGS. 3 and 4 made of zirconium / cobalt / rare earth getters, the getter takes time to activate. Therefore, it is difficult to efficiently perform the shipping inspection for determining whether the lamp characteristics are acceptable or not in a short time.

The present invention contributes to the improvement of the lamp characteristics by suppressing the hydrogen partial pressure in the outer bulb to be low from the beginning of lighting of the discharge lamp in which the arc tube is accommodated in the outer bulb.

1 is a longitudinal sectional view showing a first embodiment of a discharge lamp according to the present invention. The graph which shows the relationship between the temperature of the main getter / auxiliary getter provided in the outer bulb | ball of the discharge lamp of FIG. 1, and the hydrogen partial pressure in an outer bulb | ball. Partial sectional view showing a second embodiment of the discharge lamp according to the present invention Partial sectional view showing a third embodiment of the discharge lamp according to the present invention.

Explanation of symbols

2 outer bulb 3 arc tube 4 arc tube support 13 main getter 14 auxiliary getter

Claims (5)

In a discharge lamp provided with a non-evaporable getter that absorbs impure gas in an outer bulb that houses and arranges the arc tube, as the non-evaporable getter, the lamp is activated quickly by heat from lighting of the lamp. A main getter that can exhibit hydrogen absorption performance from the main getter, and an auxiliary getter that suppresses an increase in the hydrogen partial pressure in the outer sphere by absorbing the hydrogen when hydrogen is re-released from the main getter due to overheating of the main getter And a discharge lamp characterized by that. The discharge lamp according to claim 1, wherein the main getter is made of a zirconium-cobalt-rare earth alloy, and the auxiliary getter is made of a zirconium-aluminum alloy. The discharge lamp according to claim 1 or 2, wherein the auxiliary getter is disposed in a place where the temperature when the lamp is lit is low. 2. The discharge lamp according to claim 1, wherein each of the main getter and the auxiliary getter is formed of zirconium / cobalt / rare earth alloy, and the latter is disposed at a place where the temperature when the lamp is lit is lower than that of the former. The discharge lamp according to claim 1, 2, 3, or 4, wherein the main getter is disposed so as to face the arc tube from one end side of the arc tube.

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