JP6011111B2 - Long arc type metal halide lamp - Google Patents

Description

  The present invention relates to a long arc type metal halide lamp. More specifically, the present invention relates to a long arc type metal halide lamp in which gallium (Ga) is sealed in an arc tube, which is used to cure ultraviolet curable (UV cure) ink, paint, adhesive and the like. .

  For example, as in UV printing (UV offset printing) in the printing industry, UV-curable ink, paint or adhesive is applied to the surface of glass, metal, paper, plastic, etc. (work), and UV-irradiated to cure and dry. Therefore, mercury lamps and metal halide lamps are used.

  Compared to mercury lamps, metal halide lamps are more effective for curing and drying inks and the like by shifting the wavelength range of light around 365 nm, one of the emission lines of mercury, by devising the elements contained in the arc tube. The lamp has a light in the wavelength range of 400 to 410 nm.

  Patent Document 10 describes a small metal halide lamp in which gallium iodide and iron iodide are sealed in an arc tube and used for curing and drying ultraviolet curable ink and paint. Patent Document 4 describes a lamp having a load of 240 W / cm with a tube input of 12 kW, in which a halide of mercury, argon gas, iron and tin is enclosed in a quartz glass arc tube as an ultraviolet curing lamp.

  In recent years, such a metal halide lamp with a large tube input is also used for bonding such as bonding of liquid crystals. This type of lamp is called a so-called long arc type metal halide lamp having a long arc tube and a pair of counter electrodes at both ends of the arc tube. Recently, the area of the liquid crystal panel to be irradiated has increased in size and the ultraviolet irradiated area has increased, and therefore the arc length of the lamp has become longer.

JP 47-044975 "Discharge Lamp" (Release Date: February 23, 1972) (Patent No. 0898635) Iwasaki Electric Co., Ltd. JP 49-081035 "Metal halide lamp for copier" (release date: August 05, 1974) (Patent No. 0927642) Nippon Battery Co., Ltd. JP 03-15148 "Metal Halide Lamp" (Publication Date: January 23, 1991) (Patent No. 3060461) Mitsubishi Electric Corporation JP 07-245081 "UV Curing Lamp" (Release Date: September 19, 1995) Iwasaki Electric Co., Ltd. Japanese Patent Laid-Open No. 10-302722 “Metal Vapor Discharge Lamp” (Release Date: November 13, 1998) (Patent No. 3651535) Iwasaki Electric Co., Ltd. Japanese Patent Laid-Open No. 10-308196 "Metal Vapor Discharge Lamp" (Publication Date: November 17, 1998) (Patent No. 3648817) Iwasaki Electric Co., Ltd. JP 11-135066 "Metal Vapor Discharge Lamp" (release date: May 21, 1999) Iwasaki Electric Co., Ltd. Japanese Patent Application Laid-Open No. 11-162401 “Metal Vapor Discharge Lamp Enclosure” (Publication Date: June 18, 1999) Iwasaki Electric Co., Ltd. Japanese Patent Laid-Open No. 11-329352 “Metal halide lamp and lighting device” (release date: November 30, 1999) Matsushita Electric Works, Ltd. JP 2001-015064 “UV Discharge Lamp and UV Irradiation Device” (Date of Publication: Date) (Date of Publication: January 19, 2001) Cosmo Giken Co., Ltd. JP 2003-217507 "Metal halide lamp" (Publication date: July 31, 2003) (Patent No. 4178951) Matsushita Electric Works, Ltd. JP-A-2007-184272 “Silver-free discharge composition and gallium embedded lamp” (release date: July 19, 2007) General Electric Company JP 2011-048944 "Long Arc Type Metal Halide Lamp" (Release Date: March 10, 2011) USHIO INC.

  In order to increase the work efficiency by drying and curing the ink and adhesive in a short time while increasing the lamp length with the same output, it is necessary to increase the lamp illuminance more and more. In order to increase the lamp illuminance, it is effective to encapsulate metal gallium Ga as an iodide as described in the above-mentioned Patent Document 10.

  However, from the experience of the present inventors, it has been found that when the amount of metallic gallium is increased to improve the lamp illuminance, the light emission unevenness of the lamp is noticeable.

  In Patent Documents 1 to 13, there is no description relating to or suggesting a long arc type metal halide lamp realizing the desired uniformity described in the present application documents. Specifically, as described in this application document, (1) In order to improve lamp illuminance, the amount of metal gallium (actually added as gallium iodide) is increased, and (2) when the amount of metal gallium is increased, long We pointed out that arc-type metal halide lamps have the problem of uneven light emission, and (3) introduced the concept of “homogeneity” as an allowable limit of light emission unevenness and defined its specification value. Samples with different metal gallium content (actually defined by the ratio of metal gallium content and mercury content) in the lamp length (actually defined by the arc length) are measured and the uniformity is measured, and the specification value of the uniformity is satisfied. There is no technical description that selects only samples and defines the arc length and the amount of metal gallium (in fact, the ratio of the amount of metal gallium to the amount of mercury) from the data of these samples.

  Accordingly, an object of the present invention is to provide a long arc type metal halide lamp that increases the amount of metal gallium in the arc tube to improve lamp illuminance and achieves a desired degree of uniformity.

  In view of the above-mentioned object, the long arc type metal halide lamp according to the present invention is a long arc type metal halide lamp for drying and curing UV-curable ink, paint or adhesive, and contains at least mercury, rare earth in the arc tube. Gas and gallium iodide are enclosed, and the arc tube has an arc length La in a range of 500 ≦ La ≦ 3000 mm, and a ratio of the amount of metal gallium and mercury contained in the gallium iodide Ga (mg / cc) / Hg (mg / cc) is in a range of 3.0E-03 ≦ Ga (mg / cc) / Hg (mg / cc) ≦ 2.5E-02, and the uniformity, which is an indicator of lamp emission unevenness, is Over 70%.

  Further, the long arc type metal halide lamp according to the present invention is a long arc type metal halide lamp for drying and curing ultraviolet curable ink, paint or adhesive. In the arc tube, at least mercury, rare gas and gallium bromide are contained. The arc tube is enclosed, and the arc length La is in the range of 500 ≦ La ≦ 3000 mm, and the ratio of the amount of metal gallium to the amount of mercury contained in the gallium bromide Ga (mg / cc) / Hg (mg / cc) Is in the range of 3.0E-03 ≦ Ga (mg / cc) / Hg (mg / cc) ≦ 2.5E-02, and the uniformity, which is an indicator of the light emission unevenness of the lamp, is 70% or more.

  Furthermore, in the long arc type metal halide lamp, the arc tube has an arc length La in the range of 500 ≦ La ≦ 2000 mm, and the ratio of the metal gallium amount to the mercury amount is 7.6E-03 ≦ Ga (mg / cc ) / Hg (mg / cc) ≦ 2.5E-02.

  ADVANTAGE OF THE INVENTION According to this invention, while increasing the metal gallium in an arc_tube | light_emitting_tube and improving lamp illumination intensity, the long arc type metal halide lamp which implement | achieved the desired uniformity can be provided.

FIG. 1 is a view showing an example of a long arc type metal halide lamp according to the present embodiment. FIG. 2 is a diagram for explaining the method of measuring the uniformity employed by the present applicant. Here, FIG. 2 (A) is a diagram of the lamp being measured as viewed from the side, and FIG. B) is a view of the lamp viewed in the axial direction. FIG. 3 shows the arc length La (mm) on the horizontal axis and the ratio of metal gallium to mercury on the vertical axis Ga (mg / cc) / Hg (mg / cc) for the sample that satisfies the specification value of uniformity. ) Is a graph plotted. FIG. 4 is a graph illustrating the change in uniformity for a typical ramp selected from the range of FIG.

  Hereinafter, embodiments of a long arc type metal halide lamp according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

[Long arc type metal halide lamp]
(Construction)
FIG. 1 is a view showing an example of a long arc type metal halide lamp according to the present embodiment. In this metal halide lamp 10, sealing portions 2-1 and 2-2 are respectively formed at both ends of a long and straight tube type luminous tube 1 made of quartz glass, and molybdenum foils 3-1 and 3 are formed at these sealing portions. -2 are buried, electrodes 4-1 and 4-2 made of a refractory metal such as tungsten are respectively formed at one end of these molybdenum foils, and external lead-in lines 5-1 and 5-2 are respectively formed at the other ends. Has been.

  As will be described in detail later, a luminous material made of mercury, a rare gas, gallium halide, or the like is sealed in the arc tube.

  When electric power is supplied from the outside of the arc tube via the external lead-in lines 5-1 and 5-2, a discharge is generated between both electrodes, and vapor of mercury and gallium halide is excited by electrons, mainly 350 It emits light of ˜450 nm.

(Arctube and luminescent material)
The lamp 10 shown in FIG. 1 is called a so-called long arc discharge lamp, and has an arc length La (also referred to as “light emission length” equal to the distance between two electrodes) in a range of 500 ≦ La ≦ 3000 mm. It is. The lamp 10 has an arc tube inner diameter D = 26.0 mmφ and an arc length La = 1850 mm, for example. The lamp 10 is driven and lit at a lamp power W = 36 kW, a lamp voltage V = 2.6 kV, and a lamp current I = 13.8A.

In the arc tube, mercury (Hg) is 2.2 mg / cc, gallium iodide (GaI ₃ ) is 0.05 mg / cc, and argon (Ar) is 5 Torr (= 6.6 × 10 6) as a noble gas. ^-4 MPa).

  Here, the luminescent material will be described. Long arc lamps are becoming longer and have a wider irradiation area, and it is necessary to increase the lamp illuminance in order to dry and cure the ink and adhesive in a short time to increase work efficiency. In order to increase the lamp illuminance near the wavelength range of 400 to 410 nm which is effective for curing and drying ink and the like, it is effective to encapsulate metal gallium Ga as an iodide as described in Patent Document 10 mentioned above.

  However, from the experience of the present inventors, when the amount of metal gallium is increased, the illuminance of the lamp is improved, but uneven light emission tends to be noticeable along the axial direction of the lamp. There is “homogeneity” as an index for quantitatively indicating the unevenness of light emission. This uniformity is a problem particularly with respect to a long arc type lamp, and is indicated by a ratio of a decrease in lamp illuminance measured along the both ends from the center of the lamp axis. It is the numerical value which showed the lamp illuminance of a part in percentage. At present, there is no uniform standard for measuring method and specification value related to uniformity, and lamp manufacturers define the measuring method and specification value of uniformity as in-house standards according to the needs of their customers.

  In addition, such a long arc type metal halide lamp is often used with the lamp mounted on an irradiator. However, a lamp manufacturer often requires a predetermined lamp illuminance and uniformity of a single lamp and a predetermined lamp illuminance and uniformity when mounted on an irradiator.

  Accordingly, the present embodiment aims to achieve desired lamp illuminance and uniformity in a single lamp.

(Measurement method and specification value of uniformity)
FIG. 2 is a diagram for explaining a method of measuring the uniformity employed by the present applicant. 2A is a view of the lamp being measured as viewed from the side, and FIG. 2B is a view of the lamp as viewed in the axial direction.

  For the measurement of the uniformity, the lamp illuminance is measured with an ultraviolet illuminance meter along the lamp axis at a position 330 mm away from the lamp axis and 250 mm horizontally from the lamp axis. The ultraviolet illuminance meter used is an eye ultraviolet illuminance meter model UPVF-A1 PD405 manufactured and sold by the present applicant, equipped with a 405 nm light receiver specialized for ink curing, and the measurement wavelength range is about 350 to It is 490 nm.

  The specification value of the uniformity adopted by the present applicant is that the lamp illuminance at any location is 100% for the lamp illuminance at the center, except for 10% from both ends of the lamp along the lamp axis. Is also defined as 70% or more. In the example of FIG. 2, the standard value of the uniformity is 70% or more with respect to the central portion 1480 mm excluding 185 mm at both ends.

(Relationship between arc length and gallium iodide content)
The arc tube contains at least mercury (Hg), gallium iodide (GaI ₃ ) as a luminescent substance, and argon (Ar) as a rare gas.

  As described above, from the experience of the present inventors, it is necessary to increase the amount of gallium in order to increase the lamp illuminance. However, increasing the amount of gallium improves the lamp illuminance, but it can be seen that uneven light emission tends to be noticeable. Therefore, a large number of lamp samples having different arc lengths and encapsulated gallium amounts were prepared, and the uniformity of each sample was measured according to the measurement method described in relation to FIG. Next, samples satisfying the specification value of uniformity were extracted from these samples.

  Table 1 shows data of the arc length La of the sample satisfying the specification value of the uniformity and the ratio Ga (mg / cc) / Hg (mg / cc) of the corresponding metal gallium amount and mercury amount. 3 is a graph plotted with the arc length La (mm) on the horizontal axis and the ratio Ga (mg / cc) / Hg (mg / cc) of the metal gallium amount to the mercury amount on the vertical axis.

  As can be seen from FIG. 3, the arc length La of these samples is in the range of 500 ≦ La ≦ 3000 mm, and the ratio of metal gallium to mercury is Ga (mg / cc) / Hg (mg / cc) is 0. 3-E02 ≦ Ga (mg / cc) / Hg (mg / cc) ≦ 2.5E-02.

  Furthermore, in this development, the amount of metal gallium is increased to increase lamp illuminance. However, from the viewpoint of light emission unevenness, a certain limitation is imposed on the increase in the amount of metal gallium. Therefore, it is preferable that the amount of metal gallium is large as long as the specification value of uniformity is satisfied. For this reason, preferably sample no. Except for 14, 17, 18, 20 to 23, the arc length is in the range of 500 ≦ La ≦ 2000 mm, and the ratio of the amount of metal gallium to the amount of mercury is 7.6E-03 ≦ Ga (mg / cc) / Hg (mg / cc) ≦ 2.5E-02. Note that the ratio of the amount of metal gallium to the amount of mercury is approximately twice that of a conventional lamp.

Further, the inventors conducted a similar experiment using gallium bromide GaBr ₃ using bromine instead of iodine, and almost the same result was obtained.

(Example of uniformity)
Next, the transition of the uniformity of a typical lamp selected from the lamps shown in Table 1 (FIG. 3) will be described. Table 2 is data showing the transition of the uniformity, and FIG. 4 is a graph illustrating this. This lamp is shown in Table 1. The lamp has an arc length La = 1850 mm shown as 17 and 18. The method of measuring the uniformity is to measure the lamp illuminance of the remaining 1480 mm, excluding 185mm (corresponding to 10%) from both ends, relative to the lamp illuminance of each part with the lamp illuminance at the center as 100%. Shown in value (%).

  From FIG. 4, the lamp illuminance at each measurement point is in the range of 80.0 to 100%, which is an in-house standard for uniformity, except for the 10% portion from both ends of the lamp along the lamp axis. It can be seen that the lamp illuminance at any point satisfies 70% or more with respect to the lamp illuminance.

  As mentioned above, although the embodiment of the long arc type metal halide lamp concerning the present invention was described, these are illustrations and do not restrict the range of the present invention. Additions, deletions, changes, improvements, and the like that can be easily made by those skilled in the art to the present embodiment are within the scope of the present invention. The technical scope of the present invention is defined by the appended claims.

1: arc tube made of quartz glass, 2: sealing part, 3: molybdenum foil, 4: electrode, 5: external lead wire, 10: metal halide lamp, lamp,
D: inner diameter of arc tube, I: lamp current, V: lamp voltage, W: lamp power,
Ga: metal gallium, GaBr _3: gallium bromide

Claims (2)

In long arc type metal halide lamps for drying and curing UV-curable inks, paints or adhesives,
In the arc tube, at least mercury, rare gas, and gallium iodide are enclosed,
The arc tube has an arc length La in a range of 500 ≦ La ≦ 2000 mm,
The ratio Ga (mg / cc) / Hg (mg / cc) of the amount of metal gallium and mercury contained in the gallium iodide is 7.6E-03 ≦ Ga (mg / cc) / Hg (mg / cc) ≦ 2.5E-02,
A long arc type metal halide lamp having a uniformity of 70% or more, which is an indicator of the light emission unevenness of the lamp. In long arc type metal halide lamps for drying and curing UV-curable inks, paints or adhesives,
In the arc tube, at least mercury, rare gas and gallium bromide are enclosed,
The arc tube has an arc length La in a range of 500 ≦ La ≦ 2000 mm,
The ratio Ga (mg / cc) / Hg (mg / cc) of the amount of metal gallium and mercury contained in the gallium bromide is 7.6E-03 ≦ Ga (mg / cc) / Hg (mg / cc) ≦ 2.5E-02,
A long arc type metal halide lamp having a uniformity of 70% or more, which is an indicator of the light emission unevenness of the lamp.

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