JP2012160330A - Metal halide lamp, and metal halide lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal halide lamp arranged to have a longer life by preventing a metal halide from going into a sealed part, and a metal halide lamp lighting device arranged so that a trouble in a sealed part of a metal halide lamp is avoided even in a case where a power-supply unit for lighting a lamp switches current to turn on the lamp.SOLUTION: The metal halide lamp comprises: an arc tube made of quartz glass having therein iron as a luminescent material; holding cylinders for supporting stem parts of electrodes at both ends of the arc tube respectively; and sealed parts each having a molybdenum foil buried therein. If the length of the holding cylinders is represented by L(mm), and a current of the lamp is represented by I(A), L/I(mm/A) is 0.17 or larger. Further, at least one of tin, bismuth, gallium, lead and zinc is sealed in the arc tube. The metal halide lamp lighting device has the metal halide lamp and a power-supply unit.

Description

  The present invention relates to a metal halide lamp and a metal halide lamp lighting device.

  When bonding a glass substrate in the manufacturing process of a liquid crystal display panel, a long arc type metal halide lamp is preferably used as an ultraviolet light source for curing a sealant applied between the glass substrate. In such a manufacturing process, a lighting device including a rod-shaped metal halide lamp and a reflection mirror disposed on the back surface thereof is used.

FIG. 4 shows this apparatus. A metal halide lamp 61 is disposed in the lamp house 60. A reflection mirror 62 is disposed above the metal halide lamp 61, and the radiated light from the lamp irradiates the work W installed below. As described above, the workpiece W is obtained by applying the sealing agent 65 between the glass substrate 63 and the glass substrate 64.
In such an application, ultraviolet irradiation in the wavelength region of 300 to 400 nm is required due to the characteristics of the sealing agent 65, and a metal halide lamp in which iron that provides good light emission in the above wavelength band is sealed inside the arc tube. 61 is preferably used.

Recently, in the manufacturing process of the above-mentioned liquid crystal display panel, the input power of the metal halide lamp is switched between the irradiation time and the non-irradiation time for the purpose of keeping the amount of electric power required at the time of manufacturing low. Is going to be low. For example, in order to process one workpiece, the lamp is turned on with a relatively high power for several tens of seconds for the workpiece, and then the workpiece after irradiation is moved to the next workpiece is transferred. For several tens of seconds, the light is cut off and switched to a relatively low power to light up.
An example of such a lighting method will be described. At the beginning of lamp lighting, the above-mentioned “relatively high power” is comparable to “relatively low power”. When the amount of light emitted to the light source decreases, only the power value in the period of “relatively high power” is increased. For example, when the light emission amount decreases by 5% with respect to the initial light emission amount of the lamp, the power value is adjusted (increased) so that the relatively high power is returned to the initial light emission amount. Compensates for reduced illumination. In this way, the lamp current, voltage, and power change as the lamp is used.
The relatively high power is, for example, power that is 50% or more of the rated power consumption, and the relatively low power is power that is set to be lower than the relatively high power. is there. Here, for convenience, a mode that lights with relatively high power is referred to as a “steady power lighting mode”, and a mode that supplies current with lower power than this steady power lighting mode, that is, a mode that lights with relatively low power. This is called “power saving lighting mode”.
By switching the high power and low power alternately between the steady power lighting mode and the power saving lighting mode in this way, by performing pseudo intermittent lighting, the metal halide lamp is driven with power saving and at the same time the lamp is turned on. Ramp startability is achieved more quickly than when switching on and off, and a large number of workpieces are processed continuously.

FIG. 5 is an explanatory view of a metal halide lamp 50 according to the prior art, and is a cross-sectional view cut along a plane passing through the tube axis.
As shown in the figure, the metal halide lamp 50 includes sealing portions 55a at both ends of the arc tube 51, and a molybdenum foil 54 is embedded in the sealing portion 55a.
The electrode 52 is made of triated tungsten containing thorium oxide in tungsten. The shaft portion of the electrode 52 extends to the sealing portion and is connected to the molybdenum foil 54 described above. A cylindrical holding member 56 made of quartz glass is disposed around the electrode shaft portion 53, and the outer peripheral surface of the holding member 56 and the inner peripheral surface of the arc tube 51 are welded and joined.
Here, when a specific numerical example of the metal halide lamp is represented, the outer diameter of the arc tube 51 is 26.1 mm, the inner diameter is 22.5 mm (wall thickness 1.8 mm), and the entire length including the sealing portion. Is 600 mm, and the distance between electrodes (light emission length) is 500 mm.
The diameter of the large diameter portion at the tip portion of the electrode 52 is 3.5 mm, and the diameter of the shaft portion 53 configured to be relatively thin is 2.5 mm.
The holding member 56 made of quartz glass has an inner diameter of 2.6 mm, and its total length is 2 mm.
Here, two molybdenum foils 54 are disposed in one sealing portion, and the overall length is 31 mm, and they are shrink-sealed with a rod-shaped sealing member made of quartz glass interposed.

  The enclosure enclosed in the arc tube 51 is a rare gas, a predetermined amount of halogen, and at least iron. The input power of the lamp is 7 to 14 kW, and the input current is 7 to 28A.

JP 2006-134710 A

However, when this metal halide lamp is operated by intermittent lighting in which the high input and the low input are alternately switched as described above, the metal halide encapsulated as a luminescent material is used as a relatively low temperature portion during lamp lighting. It is unevenly distributed, and effective light emission of these inclusions (metal) cannot be obtained, and the illuminance may decrease.
In addition, the metal halide segregated in the sealing portion may react with the molybdenum foil embedded in the sealing portion to cause corrosion, resulting in failure to maintain conduction. In order to suppress such a reaction with the molybdenum foil, it is possible to prevent the metal halide from entering by using a structure in which the sealing portion temperature is higher than that of the conventional one. However, in practice, if the temperature is raised to such an extent that the intrusion of the encapsulated material can be suppressed, a problem arises due to another factor that the molybdenum foil is exposed to a high temperature and the foil melts. Even if it is increased, the lamp life cannot be extended.

  Therefore, the present invention provides an encapsulated metal while lowering the temperature of the sealing portion so as not to cause problems such as segregation of metal halide to the sealing portion in the long arc type metal halide lamp, foil corrosion due thereto, and foil fusing due to high temperature. By providing a metal halide lamp in which the metal halide does not enter the sealed portion, the power supply device has a steady power lighting mode and a power saving lighting mode, and a specific lighting method that switches on and turns on the current. An object of the present invention is to provide a metal halide lamp lighting device capable of avoiding the above-mentioned problems in the metal halide lamp and prolonging the service life of the lamp even when the lamp is turned on.

(1)
The metal halide lamp according to the present invention is
It contains at least iron as a luminescent material inside the quartz glass arc tube,
A metal halide lamp in which a holding cylinder that supports the shaft portion of the electrode is provided at both ends of the arc tube, and a molybdenum foil is embedded in the sealing portion,
When the length of the holding cylinder is L (mm) and the current of the lamp is I (A), L / I (mm / A) is 0.17 or more,
In the arc tube, at least one of tin, bismuth, gallium, lead and zinc is sealed.

(2)
Further, the metal halide lamp lighting device according to the present invention is a metal halide lamp lighting device comprising a power feeding device that supplies power to the metal halide lamp,
The power supply device includes a steady power lighting mode and a power saving lighting mode for supplying a current with lower power than the steady power lighting mode.

(1) A long-lived metal halide lamp that can suppress metal penetration into the sealing portion, can prevent corrosion and fusing of the foil, and can maintain metal emission for a long time. Can do.
(2) In the metal halide lamp lighting device, the steady power lighting mode and the power saving lighting mode in which current is supplied at a lower power than the steady power lighting mode can be switched to turn on the power. Even when the power is switched, the metal halide lamp can be reduced in illuminance reduction due to loss of the luminescent material.

It is a pipe axis direction sectional view showing the metal halide lamp concerning this application. It is an enlarged view explaining the principal part. It is the table | surface which shows collectively the lamp | ramp concerning an Example, and the lamp | ramp L / I concerning a comparative example. It is a figure explaining the light irradiation apparatus which concerns on liquid crystal panel manufacture. It is a figure which shows the structure of the metal halide lamp which concerns on a prior art.

Hereinafter, embodiments of the present invention will be described based on examples.
FIG. 1 is a cross-sectional view taken along the tube axis showing the basic configuration of a long arc type metal halide lamp according to the present invention. The metal halide lamp 10 includes sealing portions 11a at both ends of the arc tube 11, and a molybdenum foil 14 is electrically connected to the electrode 12 in the sealing portion 11a. The arc tube 11 is made of quartz glass having excellent ultraviolet transmittance.
In FIG. 2, the electrode 12 is made of triated tungsten containing thorium oxide in tungsten, the shaft portion 13 of the electrode 12 extends to the sealing portion, is connected to the molybdenum foil 54 described above, and is connected to the external lead rod 15. Has been. A cylindrical holding member 16 made of quartz glass is disposed around the electrode shaft portion 13, and the outer peripheral surface of the holding member 16 and the inner peripheral surface of the arc tube 11 are welded and joined to each other. The portion 13 is held.

  The metal halide lamp 10 includes at least iron as a luminescent substance in the interior S of the arc tube 11. Iron is an indispensable light-emitting substance that is encapsulated in order to obtain ultraviolet light in the wavelength range of 300 to 400 nm, which is the main light emission in this type of metal halide lamp 10. Further, mercury may be enclosed simultaneously with iron.

FIG. 2 shows an enlarged view of the sealing portion 11a. In the present invention, when the length of the quartz glass holding member 16 disposed around the electrode shaft portion 13 is L (mm) and the lamp current is I (A), the relationship L / I (mm / A) is 0.17 or more. This is because when the current value of the lamp is large, the current density is high, so the heat in the vicinity of the sealing portion 11a is also high, and the thermal influence on the molybdenum foil 14 embedded in the sealing portion 11a becomes larger. The position of the molybdenum foil 14 is moved away from the discharge space S by increasing the length of the holding member 16 according to the magnitude of the current. As a result, the molybdenum foil 14 can be prevented from being melted due to a high temperature, and the current supply state can be stably maintained.
As described above, since the lamp current may be set to gradually increase due to the attenuation of the light emission amount of the lamp, the maximum attainable current changes (becomes higher as the cumulative lighting time of the lamp elapses). However, the input current of the lamp is not always set higher than the rated current consumption of the lamp. Therefore, in the above relationship L / I (mm / A), the length L (mm) of the holding member 16 is set by using the value of the rated current consumption with respect to I (A), so that in any lighting state. Even if the lamp is driven, the sealing portion can be prevented from being overheated and can be driven stably.

On the other hand, when the length of the holding member 16 is made longer than the conventional one so as to satisfy the above relationship L / I ≧ 0.17, the end of the discharge space S and the end of the molybdenum foil 14 as the holding member 16 becomes longer. The amount of metal halide that permeates into the end portion K of the molybdenum foil 14 increases due to an increase in temperature difference from the portion K. In such a case, the amount of light emitted from the metal in the discharge space S decreases and the illuminance decreases.
Therefore, in order to avoid such a loss of metal halide, the present invention is characterized in that a specific metal that does not directly contribute to light emission but has a higher vapor pressure than iron is enclosed. Specifically, any metal of tin, bismuth, gallium, lead and zinc is enclosed. These specific metals are easy to encapsulate in the state of an appropriate halogen compound.
Since the specific metal group is a substance having a vapor pressure higher than that of iron, the vapor pressure can be increased during lamp operation by generating a composite compound between them and iron (Fe). As a result, the iron that has been infiltrated into the sealing portion can be kept in the discharge space S without entering the vicinity K of the molybdenum foil 14 of the sealing portion 11a.

  Here, when an example of the encapsulation ratio of the above metal to iron is given, the atomic ratio Sn / Fe of tin (Sn) and iron (Fe) is 0.25, and the ratio of bismuth (Bi) and iron (Fe) In Bi / Fe, it is 0.14. Of course, it is preferable to enclose other metals in an appropriate range in the atomic ratio with iron.

  According to such an invention of the present application, the metal halide lamp is turned on in the heat distribution state of the arc tube due to alternately and repeatedly lighting the steady power lighting mode and the power saving lighting mode lower than the steady power lighting mode. Even in the case where unevenness occurs remarkably, the luminescent material penetrates into the sealing portion and the illuminance decreases, or the molybdenum foil embedded in the sealing portion reacts with the metal halide to be corroded, so that All the problems that the conduction state is impaired and the molybdenum foil is overheated and melted can be solved, and a metal halide lamp that can stably maintain the illuminance for a long time can be provided.

Examples of the present invention will be described below, but the present invention is not limited to the following configurations.
Various lamps basically comprising the configuration of the metal halide lamp shown in FIG. 3 were manufactured.
The arc tube was made of quartz glass. The outer diameter of the tube was 26.1 mm, and the inner diameter was 22.5 mm (wall thickness 1.8 mm).
As a luminescent substance, iron was enclosed at a rate of 0.011 mg / cc, and mercury was enclosed at a rate of 0.17 mg / cc. Iron and tin were enclosed in the same manner as described above. Moreover, tin (Sn) was enclosed as a metal having a higher vapor pressure than iron at a ratio of Sn / Fe = 0.25 in terms of atomic ratio to iron.

  The current is 7 to 28 (A) by changing the length of the arc tube and the distance between the electrodes, and the length L of the holding members disposed at both ends of the arc tube is 4.8 to 13.2. (Mm), the metal halide lamps of Examples 1 to 7 having L / I in the range of 0.17 to 1.89 were produced.

  Further, in the comparative example in which none of the above-mentioned specific metal having a higher vapor pressure than iron is enclosed in the arc tube, and the length L of the holding member is 0.07 to 0.13 with respect to the lamp current. Such a metal halide lamp was produced. The current I was 15 to 27 A, the interelectrode distance was 1100 mm, and the holding member length was 2 mm.

  Each of the metal halide lamps of Examples 1 to 7 and Comparative Example 1 is switched on every 30 seconds in two stages of rated power consumption and power that is about 50% or less of the rated power consumption. I did that. As a result, in the metal halide lamp of Comparative Example 1, the molybdenum foil was overheated and melted after lighting for 542 hours, resulting in no lighting. In all the metal halide lamps of Examples 1 to 7, the state of the molybdenum foil was not changed even after lighting for 1000 hours, and the appearance of aggregation of the metal halide was not observed.

According to the present invention described above, in order to keep the temperature of the molybdenum foil embedded in the sealing portion low, the electrode shaft holding member is lengthened, and the current of the lamp is 0.17 mm / A or more. The distance between the discharge space and the molybdenum foil can be increased to avoid the problem of the foil fusing, and the metal halide in the discharge space can be lowered by lowering the temperature in the vicinity of the molybdenum foil. However, by encapsulating a specific metal with a higher vapor pressure relative to iron, which is the main luminescent material, the encapsulated specific metal and iron (Fe) form a composite compound. As a result, the vapor pressure increases, and as a result, the metal halide can be stably kept in the discharge space.
In addition, although it can be set as a metal halide lamp strong with respect to the intermittent lighting operation | movement which alternately performs a high input and a low input by setting it as such a structure, on the other hand, when it uses for a long time, an electrode becomes intermittent as a further problem. Due to the expansion and contraction in the case, there may be a problem that the bonding between the molybdenum foil and the electrode is disconnected. To solve this problem, the number of molybdenum foils embedded in the sealing portion is increased to 2 or more, and the strength of the welded portion is increased so that a metal halide lamp with a longer life can be obtained. Become.

  Needless to say, the present invention can be modified as appropriate without being limited to the contents of the above-described embodiments and examples. For example, in the above embodiment, mercury is enclosed together with iron as a luminescent material, but it is possible to use only iron. When mercury is not sealed, the same current value as when mercury is sealed can be obtained by increasing the amount of rare gas to be sealed or reducing the diameter of the arc tube.

DESCRIPTION OF SYMBOLS 10 Metal halide lamp 11 Arc tube 11a Sealing part 12 Electrode 13 Electrode axial part 14 Molybdenum foil 15 External lead rod 16 Electrode axial part holding member S Discharge space K Molybdenum foil Electrode side edge part

Claims (2)

Inside the arc tube made of quartz glass contains iron as a luminescent material,
A metal halide lamp in which a holding cylinder that supports the shaft portion of the electrode is provided at both ends of the arc tube, and a molybdenum foil is embedded in the sealing portion,
When the length of the holding cylinder is L (mm) and the current of the lamp is I (A), L / I (mm / A) is 0.17 or more,
A metal halide lamp, wherein at least one of tin, bismuth, gallium, lead, and zinc is sealed inside the arc tube.
A metal halide lamp lighting device comprising a power feeding device for supplying power to the metal halide lamp according to claim 1,
The power supply apparatus includes a steady power lighting mode and a power saving lighting mode that supplies a current with lower power than the steady power lighting mode.

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