KR101572294B1 - Long-arc type discharge lamp and light irradiation apparatus - Google Patents

Abstract

(Problem to be Solved) In a case where power is frequently switched in a long arc-type discharge lamp in which a pair of electrodes are opposed to each other in an arc tube, mercury of 0.5 mg / cm ³ or less, a metal such as iron, , The phenomenon that the sealed metal is injected into the inner wall of the arc tube is suppressed, and the decrease of the luminous intensity maintenance rate in the short term is prevented.
In the long arc type discharge lamp in which a pair of electrodes are disposed in an arc tube, mercury (Hg) is sealed in the arc tube and the amount of mercury enclosed is 0.5 mg / cm 3 or less At least one metal of iron (Fe), thallium (Tl) and bismuth (Bi) is sealed, halogen is sealed, the amount of the metal contained in the enclosed metal other than mercury is M (mol) H (mol), and H / M is in the range of 2.1? H / M? 5.0.

Description

[0001] Description [0002] LONG ARC TYPE DISCHARGE LAMP AND LIGHT IRRADIATION APPARATUS [0003]

The present invention relates to a long arc type discharge lamp and a light irradiation apparatus, and more particularly to a long arc type discharge lamp in which mercury, iron and other metals are contained in a light emitting tube, a halogen is sealed, and a light irradiation apparatus .

BACKGROUND ART Conventionally, mercury, a metal other than mercury, and a long-arc discharge lamp in which halogen is enclosed in a light-emitting tube, a so-called long arc metal halide lamp, are lamps that emit ultraviolet rays. Examples thereof include resins, adhesives, And is widely used for various treatments such as hardening of photoresist, drying, melting, or softening. Concretely, processing is performed by irradiating ultraviolet rays to an object (workpiece) coated with an adhesive or the like and causing a chemical reaction.

Japanese Unexamined Patent Application Publication No. 03-250551 discloses such a discharge lamp.

The long arc type discharge lamp will be described with reference to Fig.

The long arc type discharge lamp 1 is arranged such that a pair of electrodes 4 and 4 are opposed to each other in the tube axis direction at both ends of a quartz glass long arc tube 2, And the electrode 4 and the outer lead 5 are electrically connected to each other by the metal foil 6.

Inside the arc tube 2, 120 mg of mercury, 4 mg of iron, 12 mg of mercuric iodide, and 5.3 mg of bismuth iodide are sealed. The enclosed amount of bismuth is within a specific range with respect to iron, thereby preventing iron from adhering to the inner wall of the arc tube 2 without adversely affecting the emission spectrum of iron and mercury.

[Patent Document 1] Japanese Patent Application Laid-Open No. 03-250551

In recent years, there has been a strong demand for reducing the environmental load on such discharge lamps, and it is required that the amount of mercury enclosed in the arc tube is reduced. In addition, a reduction in the power consumption of the discharge lamp is also required.

Conventionally, in the case where the mercury content is low, the emission intensity distribution of iron is highly unevenly described in Patent Document 1. However, due to the improvement of the ballast performance of the lighting apparatus and the like, It becomes possible.

From such a background, it is required to reduce the amount of mercury in the lamp and frequently use the input power in order to reduce the power consumption.

For example, when irradiating a workpiece, it is a lighting method in which the lamp is turned on with electric power at the time of normal lighting, and when electric power is lowered, the electric power is switched again. At this time, the standby time of the lamp to be actually used is, for example, within one minute.

However, when the mercury-reduced lamp is frequently switched on as described above, there is a problem that the illuminance is remarkably lowered in a short time.

As a result of intensive investigations by the inventors of the present invention, the following findings were obtained.

The outermost surface of the quartz glass on the inner wall is cleaned with an aqueous solution of hydrogen fluoride on the inner wall portion of the lamp after the roughness has deteriorated in a short time, , The enclosed metal was contained in the region from the inner wall of the arc tube to a certain depth.

From this point of view, it was thought that the enclosed metal did not remain attached to the inner wall of the arc tube but was injected into the arc tube. This phenomenon is considered to occur when the current rapidly increases from standby to irradiation. The reason is presumed as follows.

The halogen density in the vicinity of the inner wall of the arc tube is in a low state at the time of low power standby. Therefore, when power is switched to a high power, the electron density of the arc is abruptly increased, and atoms of the enclosed metal such as iron or bismuth collide with electrons in the arc and fly toward the inner wall of the arc tube.

Conventionally, since mercury is present in a large amount, mercury functions as a buffer, and the injection of the enclosed metal into the arc tube is suppressed. However, since the amount of mercury is lowered, the buffering effect is so thin that it is considered that the filling metal such as iron or bismuth is easily injected.

In particular, it was found that the injection amount abruptly increased when the power difference between the waiting time and the irradiation time exceeded 1.5 times.

It is thought that when the enclosed metal is injected into the arc tube, the luminous material inside the arc tube is reduced and the illuminance is lowered.

As described above, according to the present invention, in a long arc-type discharge lamp in which a pair of electrodes are arranged to face each other in an arc tube and mercury of 0.5 mg / cm3 or less, a metal such as iron, To suppress the phenomenon that the sealed metal is injected into the inner wall of the arc tube and to prevent the reduction of the luminous intensity maintenance rate in a short period of time.

In order to solve the above problems, the present invention provides a long arc-type discharge lamp in which a pair of electrodes are disposed in an arc tube, wherein mercury (Hg) is sealed in the arc tube, / Cm3 and at least one of metals of iron (Fe), thallium (Tl) and bismuth (Bi) is sealed and the halogen is sealed, and the amount of the substance of the sealing metal other than mercury is defined as M (mol) And H / M is in a range of 2.1? H / M? 5.0.

Further, the present invention is a lighting mode in which two lighting modes, a standby lighting mode and a standby lighting mode, are lit, and the standby lighting mode is a lighting mode in which the lighting is performed at a lower power than the standby lighting mode. And alternately switched to the lighting mode.

Further, the present invention is characterized by comprising the above-described long arc type discharge lamp, a lighting device for supplying electric power to the long arc type discharge lamp, and a power switching means for switching the amount of supplied electric power provided in the lighting device.

According to the present invention, in a long arc type discharge lamp in which the amount of mercury enclosed in the arc tube is 0.5 mg / cm 3 or less, the amount of the material of the enclosed metal other than mercury is represented by M (mol) And the ratio H / M of these is within the range of 2.1? H / M? 5.0, it is possible to prevent the decrease of the enclosed metal as the luminescent material and to prevent the decrease of the luminous intensity maintenance rate.

Particularly, when the lighting method in which the power is frequently and largely increased is used, the effect of preventing the injection of the sealed metal into the inner wall of the arc tube is exhibited, and even if this lighting method is used, , The lighting power of the lamp can be saved.

According to the present invention, even when the lighting mode is switched by switching between the lighting mode in which at least two input powers of the pilot lighting mode and the standby lighting mode are switched and turned on, immediately after switching from the standby lighting mode to the pilot lighting mode, The halogen density in the vicinity of the inner wall of the arc tube is high and injection of the enclosed metal into the inner wall of the arc tube can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a long arc-type discharge lamp in a tube axis direction; FIG.
Fig. 2 is a diagram showing an example of a lighting device for a long arc type discharge lamp of the present invention.
Fig. 3 is a diagram showing experimental results relating to the present invention. Fig.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view of a long arc-type discharge lamp of the present invention in the tube axis direction. Fig.

In this drawing, the long arc-type discharge lamp 1 is provided with sealing portions 3 and 3 at both ends of an arc tube 2 made of a translucent material such as quartz glass, A pair of opposing electrodes 4 and 4 made of tungsten are arranged to face each other with a predetermined distance therebetween.

The root side end of each electrode 4 is bonded to a metal foil 6 embedded in the sealing portion 3, for example, molybdenum. An external lead 5 is connected to the other end of the metal foil 6 and protrudes to the outside of the arc tube 2. A power feed line is connected to the external lead 5 from a power source and a lighting circuit (not shown), and power is supplied.

In the long arc type, the distance between electrodes is longer than a predetermined length, and a long arc is formed at the time of lighting according to the distance, which is different from a short arc type providing a point light source.

More specifically, the distance between the electrodes is 5 times or more with respect to the inner diameter of the arc tube, and 10 times or more with a long electrode. This is because the lamp itself is used for scanning an object to be irradiated with a large area, or a plurality of the lamps are arrayed to uniformly irradiate the object.

Metal such as iron (Fe), thallium (Tl), tin (S), zinc (Zn), and bismuth (Bi) is filled in the light emitting tube 1 as a light emitting material.

In addition, mercury is sealed as a luminescent material or to adjust the lamp voltage. The enclosed amount is an amount of 0.5 mg / cm 3 or less.

In enclosed metals other than mercury, iron, thallium, and bismuth are suitably used as the light emitting material. The amount of each of these is, for example, 0.2 to 6 × 10 ^-6 mol / cm 3.

These materials are metals having an emission spectrum in the ultraviolet region when the lamp is sealed by being enclosed in a light emitting tube as a light emitting substance.

The enclosed halogen is, for example, iodine (I) or bromine (Br). These are enclosed in the arc tube in the state of a halide such as mercury iodide or bismuth iodide, for example.

In the present invention, the relationship between the amounts of the metals (iron, thallium, bismuth, tin, zinc, etc.) other than the above-mentioned mercury enclosed in the arc tube 1 and the amounts of halogens (iodine and bromine) is defined as follows.

(H / M) of the water mass ratio (H / M) is set to 2.1 ≤ H / M ≤ 5.0 when the mass of the metal other than mercury (M) This reason will be described later.

Examples of combinations of mercury and other metals enclosed in the arc tube 1 are listed below.

When mercury is used as the luminescent material, it is enclosed by a combination of mercury and bismuth, mercury and thallium, mercury and tin, and mercury and zinc.

When iron is used as the light emitting material, it is enclosed by a combination of iron, thallium and mercury, iron and bismuth and mercury, iron and tin and mercury, and iron and zinc and mercury.

In the light emitting tube, three or more kinds of metals including a combination of the above metals may be enclosed.

Fig. 2 shows an example of the configuration of a lighting apparatus for a long arc-type discharge lamp according to the present invention.

In this figure, the output side of the AC power supply 21 is connected to the step-up rectifier circuit 22.

The step-up rectifying circuit 22 is a rectifying circuit composed of, for example, a step-up transformer T1 whose input side is connected to an AC power source 21, a rectifying diode D1 and a smoothing capacitor C1, DC voltage and outputs it.

This DC voltage is then boosted by the boost chopper circuit constituted by the coil L3, the switching element S1, the rectifier diode D2 and the smoothing capacitor C2, and is supplied to the polarity inversion circuit 23, And outputs a voltage.

The control circuit 24 is connected to the switching element S1 (for example, IGBT and FET) of the step-up chopper circuit. By changing the switching frequency and the ON and OFF periods of the switching element S1, Can be supplied.

As a result, the input power can be switched, and the other lighting modes of the irradiation-time lighting mode and the standby-time lighting mode are switched in accordance with the signal from the control circuit 24.

The polarity inversion circuit 23 connected to the output side of the step-up rectifier circuit 22 is an inverter circuit composed of, for example, a bridge circuit and composed of switching elements Q1 to Q4 such as IGBTs and FETs connected in a bridge configuration .

ON and OFF of the switching elements Q1 to Q4 of the polarity inversion circuit 23 are driven by a driver circuit included in the control circuit 25. [

The polarity inversion is carried out in such a manner that the polarity inversion circuit drive signal X which is the drive signal of the switching elements Q1 and Q4 and the polarity inversion circuit drive signal Y which is the drive signal of the switching elements Q2 and Q3 are alternately ON, The square wave AC voltage is supplied to the discharge lamp 1 by an operation of repeating OFF.

The lighting start of the lamp is performed by applying a pulse voltage from the starter circuit 26 to the starter coil L2 connected in series to the lamp to insulate and break the gas sealed in the lamp.

A method of using the above-described lamp and a light irradiating device including the light emitting device will be described below.

Although not shown in the drawings, the structure of the light irradiation apparatus is provided with a lamp, a lamp house provided with a lamp lighting device, a mirror, and the like, and is provided with a suitable transporting device or the like in accordance with a work to be irradiated .

In the conventional method of using the lamp, the lighting frequency of the lamp is continuously irradiated for at least one hour at a time, and since a predetermined period of time is required until the illuminance is stabilized from the re-point, etc., And so on.

In the present invention, lighting is performed by at least two modes of the standby lighting mode and the standby lighting mode.

The pilot lighting mode is turned on at a predetermined input power such as a rated power, for example. In the stand-by lighting mode, the light is turned on at a lower input power than the assist lighting mode, and ultraviolet rays are not irradiated to the irradiated object in the meantime. The light is shielded by a light shielding means such as a shutter, do.

The switching of the input power is performed by, for example, the lamp lighting device shown in Fig. Further, if the input power can be switched, it is not limited to such a lighting device.

The timing of the switching is detected by a predetermined detecting means provided on a conveying device or the like, for example, and the detection signal is transmitted to the control circuit 24 of the lamp lighting device, It is possible to automatically calculate by the operation such as switching the input power by the operation of the power source. Alternatively, a predetermined timing may be input to the control circuit by a program.

The operation lighting mode and the standby lighting mode are alternately switched. In the switching cycle, the continuous lighting time in each lighting mode is within 1 minute, for example, 30 to 50 seconds in both standby and lighting. The switching of each lighting mode is completed in about 0.5 to 3.0 seconds.

By lighting in this manner, the work which is sequentially transported and transported is lit at a predetermined electric power when it is necessary to irradiate the electric power. When it is unnecessary, the work is lighted at a lower electric power than the electric power, .

However, when the power is switched and turned on in this manner, in the long arc type metal halide lamp having a small amount of mercury, injection into the inner wall of the arc tube occurs when the lamp is switched from the small power to the large power as described above, There is a problem that the amount of enclosed metal is reduced.

Table 1 shows an example of changes in voltage, current, and the like when the input power of the long arc type discharge lamp is changed.

This table shows the relationship between the input power, voltage, current and density for one lamp having a distance of about 150 cm between electrodes.

In this table, it can be seen that, in the long arc type discharge lamp, when the power is increased, the change of the current is larger than the change of the voltage.

Considering the current density in the arc tube in which the arc is formed, the inner diameter of the arc tube of the long arc type discharge lamp is almost constant in the tube axis direction, so the current density in the arc tube depends on the current value. That is, the current density is increased due to the increase of power.

Since the number of collisions of electrons and metal atoms in an arc depends on the current density, when the current density increases, the number of metal atoms moving toward the arc tube inner wall increases.

Immediately after the power is switched and increased, the temperature rise in the light emitting tube that follows it is not sufficient. Therefore, it is considered that the amount of vaporized halogen is small, the halogen density in the vicinity of the inner wall of the arc tube is low, and the metal atoms are not captured by halogen and are easily injected into the inner wall of the arc tube.

Therefore, the present invention defines the amount of the enclosed metal other than mercury and the amount of the enclosed halogen, and enriches the halogen to a metal other than mercury to increase the halogen density near the inner wall of the arc tube.

When the halogen density in the vicinity of the inner wall of the arc tube is high, it is considered that when the metal atom collides with the electrons in the arc, it easily bonds with the halogen and is injected into the inner wall of the arc tube.

As a result of analyzing the material injected into the arc tube described above, almost no injection of mercury into the arc tube was observed.

(Example)

Hereinafter, experimental results for verifying the effects of the present invention will be described with reference to the drawings.

Fig. 3 is a graph comparing the relation between the lighting elapsed time (h) and the luminous intensity maintenance rate (%) of a plurality of long arc type discharge lamps.

Here, the illuminance retention ratio is expressed as a percentage based on the illuminance at the start of lighting, with respect to the illuminance of light of a predetermined wavelength, the ratio between the illuminance at the start of lighting and the illuminance after lighting for an arbitrary time. In this experiment, light having a wavelength of 365 nm was measured, and measurement was carried out with an illuminometer having sensitivity around this wavelength.

The lamp used in the experiment is a long-arc discharge lamp with an electrode-to-electrode distance of 1450 mm, and the maximum rated power is 34.8 kW. The light emitting tube is made of quartz glass, and the electrode is made of tungsten. The details of the specifications of each lamp will be described later.

In the lamp of the comparative example, 260 mg of mercury, 10 mg of iron, 55 mg of mercury iodide, 45 mg of bismuth iodide and 6.7 kPa of xenon were sealed in an arc tube having an inner diameter of 22 mm, and a mercury amount with respect to the arc tube was 0.48 m / .

The ratio (H / M) of the amount (M) (mol) of the contained metal other than mercury to the amount (H) (mol) of the amount of the halogen contained in the lamp is 0.99.

Fig. 3 shows a case in which two lighting modes in which the difference in power is 1.5 times in the standby lighting mode in which the input power of the lamp is 11.6 kW and the standby lighting mode in which the lamp is in the 17.4 kW are switched every 60 seconds (H) and the luminous intensity maintenance rate (%), respectively.

In the lamp of the comparative example, it can be seen that the illuminance retention rate became 70% at 450 hours, and the illuminance retention rate rapidly decreased with respect to the elapsed time of lighting.

In the lamp of the first invention, 253 mg of mercury, 10 mg of iron, 90 mg of mercury iodide, 45 mg of bismuth iodide and 6.7 kPa of xenon are sealed in an arc tube having an inner diameter of 22 mm, and the amount of mercury / Cm < 3 >.

The ratio (H / M) of the amount (M) (mol) of the contained metal other than mercury to the amount (H) (mol) of the contained halogen is 2.1 in this lamp.

The lamp was turned on for switching the lighting mode as described above. As a result, the illuminance retention rate after lighting for 1000 hours was 90%, and the illuminance retention ratio after 76 hours was also 76% after 2000 hours.

That is, in this lamp, since the H / M ratio is 2.1, by increasing the halogen density in the vicinity of the inner wall of the arc tube, the enclosed metal atoms other than the mercury coming into the inner wall are combined with the halogen, .

In the lamp of the second invention, 273 mg of mercury, 24 mg of mercury iodide, 3 mg of iodine thallium and 6.7 kPa of xenon are enclosed in an arc tube having an inner diameter of 22 mm, and a mercury amount of 0.5 mg / to be.

The ratio (H / M) of the amount (M) (mol) of the contained metal other than mercury to the amount (H) (mol) of the amount of the halogen contained in the lamp is 4.0.

When the lamp was turned on for switching the lighting mode as described above, the lamp maintaining rate after lighting for 1000 hours was 96%, and the lamp maintaining rate after 92 hours was 4000 hours.

That is, even when the type of the metal to be enclosed is different, it is considered that the same effect as that of the lamp of the first invention is exhibited.

In the lamp of the present invention 3 in which the amount of the halogen was further increased in the lamp of the present invention and the H / M was 5.0, the luminous intensity maintenance rate was 96% up to 3000 hours. Incidentally, at 3400 hours, the electrode on one side was bent at the vicinity of the sealing portion, and the electrode could not be turned on. This is thought to be the corrosion of the electrode by the halogen.

However, the effect of preventing the decrease of the luminescent material is effective. Since the lifetime of 3400 hours is practically sufficient, the effect of the present invention can be exerted even when H / M is 5.0.

That is, the range of H / M is preferably 2.1? H / M? 5.0, and the effect of the present invention can be exhibited in this range. Further, it is preferable that 2.1? H / M? 4.0, and in this range, there is an effect that the electrode does not cause corrosion of the halogen.

From the above, it can be seen that in a long arc type discharge lamp in which mercury is sealed in the arc tube and the amount of mercury is 0.5 mg / cm 3 or less, the amount of the material of the enclosed metal other than mercury is represented by M (mol) And when the ratio H / M of these is within the range of 2.1? H / M? 5.0, the halogen binds to the enclosed metal near the inner wall of the arc tube, and the injection of the enclosed metal into the inner wall of the arc tube is suppressed.

As a result, it is possible to prevent the decrease of the enclosed metal as the luminescent material and to prevent the reduction of the luminous intensity maintenance rate.

Particularly, when the lighting method in which the power is frequently and largely increased is used, the effect of preventing the injection of the sealed metal into the inner wall of the arc tube is exhibited, and even if this lighting method is used, , The lighting power of the lamp can be saved.

When the lighting mode in which at least two charged powers of the standby lighting mode and the standby lighting mode are switched and turned on within one minute, even immediately after switching from the standby lighting mode to the standby lighting mode, Since the halogen density in the vicinity of the inner wall is high, the injection of the enclosed metal into the inner wall of the arc tube is prevented.

In addition, since the long time illumination can be maintained even when the power increase rate is 1.5 times or more when switching from the standby lighting mode to the pilot lighting mode, the power consumption can be saved.

1: long arc type discharge lamp 2: arc tube
3: sealing part 4: electrode
5: outer lead 6: metal foil
21: AC power supply 22: step-up rectifier circuit
23: polarity inversion circuit 24: control circuit
25: control circuit 26: starter circuit
C1: smoothing capacitor C2: smoothing capacitor
D1: Rectifying diode D2: Rectifying diode
L2: Starter coil L3: Coil
Q1: Switching element Q2: Switching element
Q3: Switching element Q4: Switching element
S1: Switching element

Claims (3)

In a long arc type discharge lamp in which a pair of electrodes are arranged to face each other in an arc tube,
Mercury (Hg) is sealed in the arc tube,
The amount of the mercury enclosed is 0.5 mg / cm < 3 &
At least one metal of iron (Fe), thallium (T1), or bismuth (Bi) is filled,
Halogen is enclosed,
Wherein the amount of the contained metal other than mercury is M (mol), the amount of the contained halogen is H (mol), H / M is in the range of 2.1? H /
The lighting is switched on in two lighting modes of the standby lighting mode and the standby lighting mode,
The standby lighting mode is a lighting mode in which the lighting is performed by a power lower than the assist lighting mode,
Wherein one of the lighting modes is alternately switched and turned on. A long arc type discharge lamp according to claim 1,
A lighting device for supplying electric power to the long arc type discharge lamp;
And power switching means for switching the amount of power applied to the lighting device. delete

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