JP3322177B2 - Long arc discharge lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a long arc discharge lamp which is an ultraviolet light source that causes a photochemical reaction such as photosterilization, photowashing or curing of a photocurable resin.

[0002]

2. Description of the Related Art Conventionally, an inert gas and mercury or xenon as a luminescent substance and an inert gas in a discharge space surrounded by a glass arc tube have been used as an ultraviolet light source for performing sterilization treatment, light cleaning treatment, or curing of an ultraviolet curable resin with ultraviolet light. Long arc discharge lamps in which the distance between electrodes is long are known. Such a long arc discharge lamp is widely used because a wide irradiation area can be secured and a photochemical reaction occurs efficiently.

[0003] By the way, with respect to a discharge lamp, when manufacturing an arc tube, a powdery glass material is melted to form an arc tube of a predetermined shape. At this time, the arc tube is formed by a high-temperature processing flame of an oxyhydrogen banner. It is inevitable that impurities such as moisture enter the arc tube. In particular, since the long arc discharge lamp has a long arc tube and a large volume of the arc tube, there has been a phenomenon that the amount of water present inside the arc tube increases.

During operation of the discharge lamp, the temperature of the arc tube rises to a high temperature of, for example, 85 to 260 ° C., and water existing in the arc tube is released into the discharge space. H ⁺ ions and OH ^- ions are generated in the discharge space. And in the long arc discharge lamp,
Since a large amount of water exists inside the arc tube, a large amount of H ⁺ ions and OH ^- ions are present in the discharge space.

The OH ^- ions present in the discharge space are repelled by the electrons flowing in the discharge space and are driven to the inner wall side of the arc tube, and the inner wall of the arc tube has a negative charge.
As a result, the electrons flowing in the discharge space try to spread uniformly in the discharge space, but the inner wall of the arc tube is negatively charged, so that the spread of the electrons is limited, and specifically, the arc is generated by the arc tube. Only occurs at the center of the tube axis, and the arc meanders and becomes unstable.

When the arc meanders like this,
The intensity of ultraviolet radiation emitted from the long arc discharge lamp becomes uneven and unstable, and as a result, the sterilization effect varies in the sterilization process, and the cleaning process also varies in the light cleaning process, and the curing of the ultraviolet curing resin hardens in the light curing process. There was a problem of insufficient curing.

[0007] In order to solve such a problem, conventionally, impurities such as H ⁺ ions and O
In order to absorb H ^- ions, a metal getter such as tantalum or zircon aluminum is used.
Zircon aluminum getters have been used to favorably absorb H ^- ions. Such a metal getter is mainly attached to an electrode supporting member extending into the discharge space and arranged in the discharge space.

[0008]

However, the metal getter has a problem that a getter effect occurs and it takes a considerable time immediately after the lamp is turned on until the arc is stabilized. More specifically, the temperature of the metal getter rises when electrons flowing in the discharge space collide with the metal gator, and only when a certain temperature or more is reached, the getter substance zircon is released from the metal getter and the OH ^- is intended to absorb the ions, i.e., metal getter in a short time after lighting of the lamp is not the temperature achieving the getter effect, therefore, the long arc discharge lamp using the metal getter, the arc becomes stable, There is a problem that it takes a considerable time for the intensity of ultraviolet radiation to stabilize.

On the other hand, in recent years, the inside diameter of the lamp has been reduced and the tube has been reduced in size, and it has become difficult to arrange a metal getter in the discharge space.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a getter effect in a short time after lamp operation, to stabilize an arc, to stabilize ultraviolet radiation intensity, An object of the present invention is to provide a long arc discharge lamp that does not need to consider the position of the getter.

[0011]

According to a first aspect of the present invention, there is provided a long arc discharge lamp in which a luminous substance and silicon tetrachloride are sealed in a discharge space surrounded by a glass arc tube. It is characterized by becoming.

According to another aspect of the present invention, there is provided a long arc discharge lamp, wherein the silicon tetrachloride is used in an amount of 0.05 to 0.5% of a total gas contained in a discharge space.
It is characterized by being.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A long arc discharge lamp according to the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory sectional view showing the configuration of the long arc discharge lamp of the present invention. The long arc discharge lamp is provided with a straight tube type arc tube 1 made of quartz glass having sealing portions 11 at both ends,
The portion surrounded by the arc tube 1 is a discharge space S. In the discharge space S, a pair of electrodes 2 are arranged so as to face each other along the tube axis of the arc tube 1. Each of the electrodes 2 is connected to an internal lead rod 21 arranged along the tube axis of the arc tube 1, and the base end of the internal lead rod 21 is supported by the sealing portion 11 of the arc tube 1 and Is connected to a metal foil 3 made of molybdenum hermetically buried in the sealing portion 11.
It is connected to an external lead bar 4 extending outward from the sealing portion 11. Then, in the discharge space S, argon is sealed as an inert gas, and mercury is sealed as a luminescent material.
Silicon tetrachloride is sealed as a getter material. The distance L between the electrodes is 90 mm.

Each of the electrodes 2 in this example is made of molybdenum, tungsten, nickel, an Fe—Ni—Mn alloy,
It is composed of a metal sleeve made of an Fe-Mn alloy or the like. Specifically, each of the electrodes 2 is held by the internal lead rod 21 in a state where the distal ends of the electrodes 2 are opposed to each other by the distal end of the internal lead rod 21 being sandwiched by the flatly crushed proximal end. ing.

[0015] Upon lighting the long arc discharge lamps, impure portions H ⁺ ions and OH present in the discharge spaces S in the following manner ^- to absorb ions. When the long arc discharge lamp is turned on, the arc tube 1 becomes approximately 120 ° C.
The water present in the arc tube 1 is discharged into the discharge space S. Then, the electrons flowing in the discharge space S collide with the moisture, thereby generating H ⁺ ions and OH ⁻ ions in the discharge space S. On the other hand, the silicon tetrachloride (SiCl ₄ ) sealed in the discharge space S is instantaneously ionized into Si ⁺ ions and Cl ⁻ ions by the collision of the electrons flowing in the discharge space S. As a result, H ⁺ ions and OH ⁻ ions in the discharge space S combine with Si ⁺ ions and Cl ⁻ ions to form SiO ₂ and HCl. This SiO ₂ and HCl
In this case, the reversible reaction due to discharge is unlikely to occur, and exists in the light emitting space S in a stable state.

That is, when such a long arc discharge lamp is turned on, silicon tetrachloride is instantaneously ionized to be able to absorb H ⁺ ions and OH ^- ions, and the temperature of the arc tube 1 rises. Discharge space S
H ⁺ ions and OH occurring within ^- so sequentially absorb ions, appeared getter effect immediately after lamp ignition, the arc becomes stable in a short time after the lamp lights, ultraviolet radiation intensity is stabilized.

Further, since a metal getter is not used and a gas of silicon tetrachloride is used as in the prior art, there is no need to consider the arrangement position of the getter, and the degree of freedom is added to the lamp design, and specific In this case, a long arc discharge lamp of a small tube type having a small inside diameter can be manufactured.

As the long arc discharge lamp, the lamp shown in FIG. 2 may be used. In this long arc discharge lamp, a pair of electrodes 5
Are arranged so as to face each other along the tube axis.
The electrode 5 has a cylindrical linear portion 51 made of tungsten extending along the tube axis direction of the arc tube 1, and a wire made of tungsten is attached to a tip portion 51 a of the linear portion 51 by the tube axis of the arc tube 1. A first coil portion 52 wound and fixed five turns along the direction, and a tip portion 51a of a straight portion 51
At a position closer to the sealing portion 11, the second coil portion 53 is wound cylindrically 20 turns along the tube axis direction of the arc tube 1 around the straight portion 51 following the first coil portion 52. Have been. The same reference numerals as those in FIG. 1 indicate the same parts.

[0019]

[Long arc discharge lamp A of the present invention]

Material: arc tube; quartz glass Shape: total length 160 mm, inner diameter 8 mm, distance between electrodes 90 m
m, discharge space volume 6.4 cc, filling: argon gas (filling pressure 5.32 kPa), mercury 0.138 mg, silicon tetrachloride (SiCl ₄ ) 0.1% power consumption: 5.0 W ultraviolet radiation intensity (irradiation distance) 42 mm) 1.2 mW / cm
^Two

<Experimental Example 1> Long arc discharge lamps B and C for comparison were manufactured under the following conditions. [Long arc discharge lamp B for comparison] Filling substance: argon gas (filling pressure 5.32 kPa), mercury 0.138 mg, metal getter: zircon aluminum 1 g The other components are the same as those of the long arc discharging lamp A of the present invention. [Long Arc Discharge Lamp C for Comparison] Filling substance: argon gas (filling pressure 5.32 kPa), 0.138 mg of mercury, and other structures are the same as those of the long arc discharge lamp A of the present invention.

The above-mentioned long arc discharge lamps A, B, C
An experiment was conducted to examine the change in the intensity of ultraviolet radiation after lighting using. The results are shown in FIGS. 3, 4, and 5. It can be seen that the comparative long arc discharge lamp B takes 56 hours for the getter effect to appear and for the ultraviolet radiation intensity to stabilize, as shown in FIG. This is because it takes a considerable time before the temperature of the metal getter rises and zircon as the getter substance is released. On the other hand, in the long arc discharge lamp A of the present invention, as shown in FIG. 4, it was confirmed that the getter effect appeared in a very short time of 10 minutes immediately after lighting and the ultraviolet radiation intensity was stable. In addition, as shown in FIG. 5, the comparative long arc discharge lamp C does not use a getter, so that the ultraviolet radiation intensity is not stable. From these results, it was confirmed that the long arc discharge lamp A of the present invention exhibited a getter effect in a short time and stabilized the ultraviolet radiation intensity as compared with the long arc discharge lamp B using a metal getter.

<Experimental Example 2> Using the long arc discharge lamp A of the present invention shown in FIG. 1, the amount of silicon tetrachloride was changed and the time until the ultraviolet radiation intensity was stabilized was examined. FIG.
As is clear from the results, when the amount of silicon tetrachloride is in the range of 0.05% to 0.5% of the total gas sealed in the discharge space, the ultraviolet radiation intensity is stable within 10 minutes after the lamp is turned on. It was confirmed that. This is because if the amount of silicon tetrachloride is 0.5% or more, the amount of silicon tetrachloride is too large, and the discharge is inhibited, so that the ultraviolet radiation intensity is not stabilized. if less, present in emission space H ⁺ ions and OH ^- UV radiation intensity can not be sufficiently absorbed ions is not stable, therefore, tetramers of silicon tetrachloride is 0.05% to 0.5% Then, it was found that the getter effect appeared surely and in a short time after lighting, the arc was stabilized, and the ultraviolet radiation intensity was stabilized.

[0023]

According to the long arc discharge lamp of the present invention, since silicon tetrachloride is sealed in the discharge space surrounded by the glass arc tube, the silicon tetrachloride ionizes immediately after the lamp is turned on. Since the impurities generated in the discharge space can be absorbed and the impurities generated in the discharge space are sequentially absorbed as the temperature of the arc tube rises, a getter effect appears in a short time after the lamp is turned on, and the arc becomes stable. , UV radiation intensity is stable.

Further, since a metal getter is not used and a gas of silicon tetrachloride is used as the getter as in the prior art, there is no need to consider the position of the getter, and the degree of freedom in designing the lamp is increased.

Further, by setting the amount of silicon tetrachloride to be 0.05 to 0.5% of the total gas contained in the discharge space, a getter effect is surely exhibited, an arc is stabilized, and ultraviolet radiation is suppressed. Strength is stable.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing a configuration of a long arc discharge lamp of the present invention.

FIG. 2 is an explanatory sectional view showing a configuration of a long arc discharge lamp according to another embodiment of the present invention.

FIG. 3 is an explanatory diagram of experimental data of ultraviolet radiation intensity after lighting of the long arc discharge lamp of the present invention.

FIG. 4 is an explanatory diagram of experimental data of ultraviolet radiation intensity after lighting of a comparative long arc discharge lamp using a metal getter.

FIG. 5 is an explanatory diagram of experimental data of ultraviolet radiation intensity after lighting of a comparative long arc discharge lamp that does not use a getter.

FIG. 6 is an explanatory diagram of experimental data on the amount of silicon tetrachloride and the time until the ultraviolet radiation intensity is stabilized in a long arc discharge lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Arc tube 11 Sealing part 2 Electrode 3 Metal foil 4 External lead rod 5 Electrode S Discharge space

Claims (2)

(57) [Claims] 1. A long arc discharge lamp characterized in that a light emitting substance and silicon tetrachloride are sealed in a discharge space surrounded by a glass arc tube. 2. The long arc discharge lamp according to claim 1, wherein the silicon tetrachloride accounts for 0.05 to 0.5% of the total gas charged in the discharge space.