TWI463523B - Metal halide lamp - Google Patents

Description

Metal halide lamp

The present invention relates to a metal halide lamp used for curing a UV-curable coating or a photopolymer reaction of a functional polymer film, and more particularly to a lamp tube capable of suppressing contact between a lamp tube and a water-cooled cooling portion. A metal halide lamp with a local temperature drop.

It is known that the metal halide lamp of Japanese Patent Laid-Open No. Hei 03-250549 (Prior Art 1) suppresses short-wavelength ultraviolet rays of 340 nm or less by encapsulating metal ruthenium or ruthenium halide together with iron and mercury in an airtight container. An ultraviolet irradiation lamp having a high luminous intensity near 365 nm.

The technique of the prior art 1 described above requires the management of the temperature of the arc tube of 600 to 850 ° C in order to ensure stable lighting of the lamp. If it reaches 850 ° C or higher, the enclosed iron will penetrate into the discharge vessel made of quartz glass to cause blackening, which may cause the illuminance to decrease or the tube to bend. Therefore, in order to reduce the temperature of the lamp, it is considered to use a water cooling method to connect the cooling method. In order to improve the cooling efficiency of the cooling method, it is necessary to keep the interval between the lamp tube and the cooling portion at about several mm.

However, in recent years, as the system has become larger, the lamp tube has been required to be elongated. In the case of the water-cooling method, not only the interval between the water-cooling type cooling unit and the lamp tube is only about several mm, but also the tube temperature is increased due to the increase in the temperature of the tube due to the slenderening, and the tube is considered to be in contact with the water-cooling type cooling unit. If the lamp is in contact with the water-cooled cooling unit, the vapor pressure in the lamp is reduced due to the concentration of mercury in the lamp, and the lamp voltage is lowered. As a result, there is a problem that the illuminance is lowered.

SUMMARY OF THE INVENTION An object of the present invention is to provide a metal halide lamp which can suppress a local temperature drop of a lamp tube when a lamp tube comes into contact with a water-cooling type cooling portion.

Hereinafter, the best mode for carrying out the invention will be described in detail with reference to the drawings.

1 to 3 are diagrams for explaining one embodiment of the metal halide lamp of the present invention, FIG. 1 is a basic structural view, FIG. 2 is an enlarged view of a main portion of FIG. 1, and FIG. 3 is an I-I' line of FIG. Sectional view.

In FIG. 1, for example, tungsten electrodes 121 and 122 are disposed inside the both ends in the longitudinal direction of the discharge vessel 10 which is made of quartz glass having ultraviolet light transmittance and which forms the discharge space 10. The discharge vessel 11 is composed of, for example, a single-layered tube having an outer diameter Φ of 27.5 mm, a wall thickness m of 1.5 mm, and an emission length L of 2000 mm.

The electrodes 121 and 122 are soldered to one ends of the metal foils 141 and 142 via inner leads 131 and 132, respectively. The other ends of the metal foils 141, 142 are soldered to one end of the lead other than the one shown. The metal foils 141, 142 are sealed by heating the inner leads 131, 132 of the discharge vessel 11 to the discharge vessel 11 at one end of the outer lead.

The metal foils 141 and 142 may be any one of those suitable for the thermal expansion coefficient of the quartz glass forming the discharge vessel 11, and molybdenum is used as an example suitable for the conditions. In the lead wires that are connected to the metal foils 141 and 142 at one end, for example, the power supply leads 161 and 162 electrically connected to the ceramic sockets 151 and 152 are insulated and sealed and connected to a power supply circuit (not shown).

In the discharge vessel 11, argon gas, which is a rare gas for sustaining arc discharge, is sealed, and at least one of mercury, mercury iodide, and a metal for emitting ultraviolet light, that is, iron, tin, and the like, and a halogen are enclosed.

As shown in FIGS. 2 and 3, a projection 17 having a tip end in a pointed shape or a curved shape is integrally formed on the outer surface of the discharge vessel 11 between the electrode 121 and the electrode 122.

The bumps 17 may be formed on at least one of the peripheral faces of the discharge vessel 11. FIG. 4 is a cross-sectional view corresponding to FIG. 3 for explaining another embodiment of the metal halide lamp of the present invention. In this embodiment, the projections 17 are formed in plural in the circumferential direction of the discharge vessel 11.

Further, when the plurality of projections 17 are formed, they are not necessarily formed on the same circumferential surface. 5 and FIG. 6 are diagrams for explaining another embodiment of the metal halide lamp of the present invention, wherein FIG. 5 is an enlarged view corresponding to FIG. 2, and FIG. 6 is respectively referred to as IIa-IIb of FIG. Sectional view of the IIc-IId and IIe-II lines. In this embodiment, the positions of the plurality of projections 17 are shifted from the same circumferential surface along the longitudinal direction of the discharge vessel 11.

Further, the bumps 17 are formed in at least one place in the longitudinal direction of the discharge vessel 11. In the case of the complex number, it may not be formed on the same line as the axial direction.

The protrusion 17 is different from the exhaust pipe mark, also referred to as a needle tube, for enclosing the rare gas or the like into the discharge vessel 11, and the height of the protrusion 17 from the outer peripheral surface of the discharge vessel 11 is higher than that of the exhaust pipe. . In addition, the sealed portion of the discharge vessel 11 can be used without the need for an exhaust pipe mark, so that it does not exist.

The height of the protrusion 17 is determined according to the positional relationship between the lamp tube and the water-cooling type cooling mechanism, so it is not particularly specified, but it is preferably 1~ considering that it does not contact the cooling mechanism and does not affect other characteristics. About 3mm.

Here, when the counter electrode 121 and 122 are supplied with a lamp voltage of 2300 V, a lamp current of 10.3 A, and a potential gradient of 11.5 V/cm, ultraviolet light having a high luminous intensity in the vicinity of 365 nm can be obtained. The mercury entrapment amount at this time was 0.9 mg/cc, the encapsulation amount of mercury iodide was 0.08 mg/cc, the encapsulation amount of iron was 0.01 mg/cc, and the encapsulation amount of tin was 0.005 mg/cc.

FIG. 7 and FIG. 8 are views for explaining an embodiment in which the metal halide lamp 100 configured as shown in FIG. 1 is applied to an ultraviolet irradiation device including a water-cooling type cooling mechanism. FIG. 7 is a system configuration diagram, and FIG. Figure III is a cross-sectional view taken along line III-III'.

The ultraviolet irradiation device includes a metal halide lamp 100 and a water cooling unit 200. The metal halide lamp 100 and the water-cooling unit 200 are positioned at a specific interval by a spacer 41a and a spacer 41b attached to the sockets 151 and 152 of the metal halide lamp 100.

The water-cooling unit 200 is made of a transparent material such as a cylindrical quartz glass, and includes an inner tube 21 and a tube 22 provided outside the inner tube 21 to have a double pipe structure. The metal halide lamp 100 is enclosed in the inner tube 21.

The water-cooling unit 200 circulates the coolant 24 such as water from the outside through the connecting pipes 23a and 23b provided at the outer peripheral end. As shown in FIG. 8, the coolant 24 is injected from the connection pipe 23a at a lower temperature, and is discharged from the connection pipe 23b to cool the metal halide lamp 100 and become hot. After the cooling liquid 24 discharged after the heat is cooled, it is reinjected from the connection pipe 23a.

On the outer surface of the outer tube 22, a metal oxide film containing a metal oxide is attached as needed. The metal oxide contains at least one of TiO ₂ , CeO ₂ , ZnO ₂ , SnO ₂ , and ZrO ₂ .

The metal oxide film is adjusted in composition to absorb a wavelength component of 300 nm or less of the ultraviolet light emitted from the metal halide lamp 100.

Further, when light is emitted from the metal halide lamp 100, the metal oxide film adhering to the outer surface of the outer tube 22 absorbs a wavelength component of 300 nm or less. Therefore, the ultraviolet ray of the 300-430 nm band which is effective for curing the resin penetrates the water-cooling unit 200, and is irradiated to an object to be irradiated such as a resin.

The case where the metal halide lamp 100 having the diameter of the inner tube 21 of the water-cooling unit 200 is 32 mm and the diameter of the outer tube 22 is 36 mm is considered to maintain a constant power in the water-cooling unit 200. The distance between the inner tube 21 of the water-cooling unit 200 and the metal halide lamp 100 is at most about 2 to 3 mm in consideration of the cooling efficiency of the water-cooling unit 200.

The distance between the elongated metal halide lamp 100 having a light-emitting length of about 2000 mm and the water-cooling unit 200 is only about 2.25 mm. In this case, even if the metal halide lamp 100 is attached to the water-cooling unit 200 in a non-contact state at the time of installation, the metal halide lamp 100 is bent over time due to thermal stress or the like. Thereby, the mercury in the tube is concentrated in the contact portion, which causes the vapor pressure to drop, and the lamp voltage is lowered accordingly.

At this time, even if the metal halide lamp 100 is bent and brought into contact with the water-cooling unit 200, only the projections 17 formed on the metal halide lamp 100 are contacted in the water-cooling unit 200. Thereby, localized cooling of the discharge vessel 11 can be alleviated.

The metal halide lamp 100 and the inner tube 21 of the water-cooling unit 200 when the deformation of the protrusion 17 caused by heat during lighting can be prevented by setting the projections 17 to the metal halide lamp 100 having an experimental value of more than 2000 mm. Make intimate contact to ensure electrical characteristics consistent with the design.

Since the front end of the projection 17 has a pointed shape or a curved shape, even if it is in contact with the water-cooling unit 200, the contact area with the inner tube 21 of the water-cooling unit 200 can be minimized. Therefore, the temperature drop in a specific portion of the discharge vessel 11 can be suppressed.

Thereby, even if it is used for the cooling unit of the water cooling method, an elongated metal halogen lamp can be utilized.

Fig. 9 is a view showing a metal halide lamp 100 for forming a plurality of projections 17 as shown in Figs. 5 and 6 along the circumferential direction of the discharge vessel 11, and is suitable for use in an ultraviolet irradiation apparatus having a water-cooling type cooling mechanism. The embodiment is described as a cross-sectional view corresponding to Fig. 8.

In this case, the projection 17 of the discharge vessel 11 can be reliably brought into contact with the cooling unit 200 regardless of the bending direction of the discharge vessel 11.

Further, the projections 17 are provided in plural portions along the longitudinal direction of the discharge vessel 11, whereby the projections 17 of the discharge vessel 11 can be reliably brought into contact with the cooling unit 200 regardless of the bending position of the discharge vessel 11 in the longitudinal direction.

10. . . Discharge space

11. . . Discharge capacitor

17. . . Bulge

twenty one. . . Inner tube

twenty two. . . Outer tube

23a, 23b. . . Connecting pipe

twenty four. . . Coolant

41a, 41b. . . Spacer

100. . . Metal halide lamp

121, 122. . . electrode

131, 132. . . Inner lead

141, 142. . . Metal foil

151, 152. . . socket

161, 162. . . lead

200. . . Water cooling unit

Figure 1 is a view showing the basic configuration of an embodiment of the metal halide lamp of the invention;

Figure 2 is an enlarged view of the main part of Figure 1;

Figure 3 is a cross-sectional view taken along line I-I' of Figure 1;

Figure 4 is a cross-sectional view corresponding to Figure 3 for explaining another embodiment of the metal halide lamp of the present invention;

Figure 5 is an enlarged view corresponding to Figure 2 for explaining another embodiment of the metal halide lamp of the present invention;

Figure 6 is a cross-sectional view taken along line IIa-IIb, IIc-IId, and IIe-II of Figure 5;

Figure 7 is a system configuration diagram for explaining an embodiment of the metal halide lamp of the present invention for use in an ultraviolet irradiation device;

Figure 8 is a sectional view taken along line III-III' of Figure 7;

Fig. 9 is a cross-sectional view corresponding to Fig. 8 for explaining another embodiment of the metal halide lamp of the invention for use in an ultraviolet irradiation device.

10. . . Discharge space

11. . . Discharge capacitor

17. . . Bulge

121, 122. . . electrode

131, 132. . . Inner lead

141, 142. . . Metal foil

151, 152. . . socket

161, 162. . . lead

Claims (8)

A metal halide lamp comprising: an airtight container made of an ultraviolet ray-permeable material and having a gas-tight discharge space; and a pair of discharge electrodes arranged in the opposite direction a hermetic container in the axial direction of the hermetic container; the enclosed material containing a sufficient amount of rare gas, mercury, halogenated metal, and a protrusion formed in the above-mentioned discharge space to maintain an arc discharge; The projection is higher than the height of the tube mark when a central portion of the airtight container is formed in the longitudinal direction and a tube trace for introducing the enclosure into the airtight container is formed. The metal halide lamp of claim 1, wherein the protrusion is provided at least in a surface outside the longitudinal direction of the airtight container. The metal halide lamp of claim 1, wherein the protrusion is thicker on the side of the airtight container, and the front end is thinner. The metal halide lamp of claim 1, wherein the front end of the protrusion is a spire or an arc shape. The metal halide lamp of claim 1, wherein the protrusions are formed in plural in a circumferential direction of the airtight container. The metal halide lamp of claim 5, wherein the plurality of the above-mentioned protrusions are formed at different positions on the same line as the axial direction. The metal halide lamp of claim 1, wherein the airtight container is disposed in a water-cooled cooling unit. A metal halide lamp according to claim 7 wherein said airtight container is adapted to The protrusion is disposed in the water-cooling type cooling unit without contacting the water-cooling type cooling unit.