JPS63213830A - Ultraviolet-ray irradiating device - Google Patents

Abstract

PURPOSE:To moderately cool a high pressure discharge lamp and a reflector without adjusting an exhausting means which forcibly discharges air through an exhaust port whether a transmissive member exists or not, by providing a transmissive member attaching part which attaches the ultraviolet ray-transmissive member to close a light projection aperture part by an object to be irradiated and specifying the distance between the top part of a lamp tube body and the exhaust port. CONSTITUTION:A transmissive member 10 is arranged to close a light projection aperture 6 of a reflector 5 and consists of a light-transmissive plate 10, which intercepts inflow of gas and permits ultraviolet rays to pass through, and a frame member 10b which is engaged with the transmissive member attaching part, which is provided in the end part of a lower face aperture 2 of an enclosure 1 and consists of a U-shaped rail, and fixes the light-transmissive plate 10a. In this case, since a length L between the top part of the tube body and an exhaust port 7 is set to 0.7-1.1-fold tube body diameter D, the tube wall temperature of the tube body of a lamp 4 is kept within an allowable temperature range whether the transmissive member 10 exists or not, and a required ultraviolet output is obtained, and the reduction of the life of the lamp due to a failure in transmission of the lamp tube body is prevented.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention includes a high pressure discharge lamp that transmits infrared light.

The present invention relates to an ultraviolet irradiation device using a reflector coated with an ultraviolet-reflective multilayer interference film.

(Prior Art) In the printing process of printed plywood, printed wiring boards, newspaper printing, etc., there is a known method of curing the paint, ink, etc. by irradiating ultraviolet rays onto a substrate coated with ultraviolet-curable paint, ink, etc. There is.

In such a method, for example, a reflector housing a high-pressure mercury lamp or a metal halide electric lamp is irradiated with ultraviolet rays, and heat is applied to the apparatus itself, paint, ink, etc., and the substrate, damaging the apparatus or causing the photochemical reaction of ultraviolet curing. Generally, a structure is adopted in which the air around the high-pressure discharge lamp is exhausted and cool air is sucked in to remove the heat inside the device. However, with this structure, although the cooling effect at the bottom of the tube where cold air hits the surface of the tube is high, eddy currents are generated at the top of the tube, reducing the cooling effect. There is a problem in that the temperature distribution on the surface of the tube becomes non-uniform, and localized high heat occurs particularly on the top side of the tube. The high-pressure discharge lamp used in this type of ultraviolet irradiation device is made of quartz glass, but in order to prevent devitrification of the tube due to the above-mentioned localized generation of high heat, the tube wall temperature of the tube must be approximately 800°C. It is preferable not to exceed. Furthermore, in order to stably output ultraviolet rays from the lamp, it is necessary to maintain the tube wall temperature of the tube at approximately 600° C. or higher, and to increase and maintain the vapor pressure within the lamp tube to a predetermined level. These things are shown in Figure 7.

120W/CI shown in Figure 8! ! , using an 8.4 kW metal halide lamp, is clear from the relationship between lamp temperature and lamp life, and between lamp temperature and ultraviolet output. In other words, from Fig. 7, when the lamp temperature is below 600°C, the ultraviolet output is extremely reduced, and from Fig. 8, when the lamp temperature is 800°C or less,
It can be seen that the lamp life becomes extremely short in the above case. Hereinafter, a temperature range of 600°C to 800'C will be defined as an allowable temperature.

Nowadays, it has become industrially accepted to use high-pressure discharge lamps with large electrical inputs, especially discharge lamps with a power output of 90 W or more per 1 cm of arc length, as used in the experiments shown in Figures 7 and 8 above. , maintaining the permissible temperature of this type of lamp is a fundamental challenge.

For such a task, i.e. when the arc length is 1 cm
In an ultraviolet irradiation device using a high-pressure discharge lamp of 90 W or more per unit, for example, Japanese Patent Publication No. 55-162 is designed to keep the temperature of the tube wall of the high-pressure discharge lamp uniform.
The one described in Publication No. 81 was proposed.

The method described in Japanese Patent Publication No. 55-16281 is designed to reduce the distance between the top side of the lamp surface and the cooling air suction part provided at the deepest part of the concave reflector to be less than 273 times the tube diameter of the lamp. , to prevent the generation of vortices. Further, in this device, the light emitting opening surface of the reflecting mirror is opened, cooling air is sucked from the entire opening of the reflecting mirror, and the cooling air flows along the tube wall of the tube body.

(Problem to be Solved by the Invention) However, when a reflector coated with a multilayer interference film that transmits infrared rays and reflects ultraviolet rays is used for a lamp, the radiant heat from the mirror is extremely reduced. Since the temperature near the top is low, if the positional relationship between the lamp and the reflector is set within the range described in the above-mentioned publication, the temperature of the lamp will be below 600° C., which may reduce the ultraviolet output.

Regarding the reflector, if the lamp is placed extremely close to the deepest part of the reflector, the temperature near the deepest part of the reflector will be 34°C.
If the temperature rises far above 0°C, there is a risk that local damage may occur due to thermal strain.

When actually using the above-mentioned ultraviolet irradiation device, for example, a separate conveyor or other transport means is installed under the light projection opening, and the object to be irradiated is placed on the conveyor and passed under the light projection opening to cure the ink. However, in the above equipment, the infrared rays emitted directly downward from the lamp are not removed, so even if the irradiated object is somewhat resistant to heat, or the conveyor speed is increased, that is, even a short period of ultraviolet irradiation will not cure the object. limited to those who do.

Therefore, when curing an object to be irradiated that does not meet the above conditions, a UV transmitting member that removes energy wavelengths other than UV rays is required under the light projection aperture of the above device, although some UV rays may be absorbed. .

Furthermore, even without considering the hardening properties or thermal deformation properties of the irradiated object, if the irradiated object is paper-like, for example, and there is no transparent member, there is a problem that the irradiated object may be lifted up by the exhaust means. Therefore, it is conceivable to use, for example, a quartz plate as the transparent member.

However, so that there is a gap at the open end of the reflector,
In addition, when an ultraviolet transmitting member is provided to close the light projection opening, the gas flow differs from the gas flow in a state where there is no transmitting member. For example, optimal ultraviolet output can be obtained by setting the lamp position, in other words, the distance between the top of the tube and the exhaust port to be 1.2 of the diameter of the lamp tube.
If it is set much smaller than the lamp tube diameter, the lamp will be overcooled, the lamp voltage will drop, and the ultraviolet output will be drastically reduced. Therefore, depending on the position of the lamp, when the transmitting member is attached to such an ultraviolet irradiation device, the lamp is cooled appropriately and the UV output is good, but when the transmitting member is removed, the lamp heats up. This will dramatically shorten the lamp life. Or, if there is no transparent member, the lamp will be cooled appropriately and the UV output will be good, but if the transparent member is attached, the lamp will become overcooled and the UV output will be extremely reduced. In many cases, the lamp cannot be put to practical use, and the exhaust air volume must be readjusted each time, and in many cases, even if the exhaust air volume is adjusted, the lamp life will be shortened. However, it is rare that a practical UV output cannot be obtained.

Although it is possible to adjust the amount of air discharged, there is a high risk of the lamp being destroyed due to an adjustment error, and it requires considerable effort for the user who removes the transparent member many times a day.

Therefore, for example, when curing this type of irradiated object, it is conceivable that a device with a transparent member and a device without it may be required, but there is a problem that the design cost, manufacturing cost, etc. are relatively high. .

The present invention has been made in consideration of the above-mentioned circumstances, and uses a reflector coated with a multilayer interference film that transmits infrared rays and reflects ultraviolet rays, which includes a high-pressure discharge lamp with an arc length of 90 W or more per 1 cm. □In devices that emit light, the temperature of the tube wall of the lamp body can be maintained within an appropriate range regardless of the presence or absence of a transparent member that blocks the light emitting opening, and without adjusting the exhaust means, and the devitrification of the lamp body can be maintained. Another object of the present invention is to provide an ultraviolet irradiation device that can effectively prevent an extreme drop in ultraviolet output and prevent deformation of a reflector.

[Structure of the invention]

(Means for Solving the Problems) The ultraviolet irradiation device of the present invention has a high-pressure discharge lamp, a rectangular light projection opening on the front side, and an exhaust port located on the back side of the lamp, A reflector having a concave cross-section and coated with an infrared-transmissive and ultraviolet-reflective multilayer interference film is disposed facing the lamp, and a reflector is provided near the side of the light emitting aperture and is located below the light emitting aperture. There is a transmitting member mounting part for attaching a light transmitting member that transmits ultraviolet light passing through the light transmitting aperture, and when a transmitting member is attached near these transmitting member attaching parts, gas is removed from near the side of the light transmitting aperture into the reflector. and an exhaust means for forcibly exhausting the gas around the lamp from the exhaust port.

The above-mentioned high-pressure discharge lamp is a straight tube type with a power of 90 W or more per 1 cm of arc length, and the distance between the above-mentioned exhaust port and the top of the tube is within the range of O.7 or more and 1.1 or less of the tube diameter. It is characterized in that it is provided so that

The above-mentioned transmitting member attachment part may be attached and detached under the light emitting aperture, and may be a rail-shaped one provided on both sides of the light emitting aperture end, or simply a transmitting member attached below both sides of the light emitting aperture end. This includes those with blocks that support both ends. Furthermore, in the absence of the ultraviolet irradiation device, that is, the transmitting member, most of the gas exhausted from the exhaust port is taken in from the light projection opening.

The gas inlet may be provided in advance near the transmitting member mounting portion of the reflector, or may be provided on both sides of the transmitting member. The gas inlet port provided in advance in the reflector is for supplementary gas inflow into the reflector when there is no transmitting member.

(Function) The ultraviolet ray irradiation device of the present invention has a transmitting member attachment part that allows the ultraviolet transmitting member to be attached so as to close the light emitting opening depending on the object to be irradiated, and the UV transmitting member has a transmitting member attachment part that can be attached to the lamp body top and the exhaust port. By providing a distance between 0.7 and 1.1 of the lamp tube diameter, high-pressure discharge lamps and reflective It cools the body appropriately.

These matters will be explained with reference to FIGS. 3 to 5.

As the high-pressure discharge lamp 4, the lamp tube has a diameter of 27 m.

Total length 840 shoes, lamp power 8.4kW, arc length 1
FIG. 3 shows the relationship between the temperature of the high-temperature part, the low-temperature part, and the reflector of the lamp tube wall and the exhaust air volume when the lamp position is changed using a metal halide lamp filled with iron-based components of 120 W per cm. In addition, in the above device, the relationship between the temperature of each part and the exhaust air volume when the transparent member is removed is
As shown in the figure. Figure 5 briefly shows the relationship between reflector temperature and reflector life.

In Figure 3, the lamp is positioned close to the exhaust port of the reflector, that is, the distance between the top of the lamp and the exhaust port is 273 mm.
It is set to 0.6 below, and the exhaust port is not shown. When the lamp is exhausted by the exhaust means, the low temperature part of the lamp is 7.5r.
If the temperature exceeds rt3/min, it becomes impossible to maintain approximately 600° C., which is the appropriate temperature for stably outputting ultraviolet rays.

However, if the exhaust air volume is reduced in order to maintain the temperature at about 600° C. for stable output of ultraviolet rays, the temperature of the reflector becomes 340° C. or higher in the absence of the transmitting member as shown in FIG. 4. The reflector that transmits infrared rays and reflects ultraviolet rays is 340
If the temperature is higher than 340°C, the lifespan will be extremely shortened due to thermal effects, so it should not be allowed to rise above 340°C (Figure 5).

That is, in practice, the exhaust air volume is never used at less than 8 m/min. Therefore, the lamp position, ie, L/D, is 0.
Must be 7 or higher.

Next, as shown in FIG. 4, in the above apparatus, when the above transparent member was removed and a similar experiment was carried out, the distance was reduced by 30
If m, that is, L/D, is made larger than 1.1, the high temperature part of the lamp tube wall will exceed the allowable temperature, and L/D will become 1.
．． It can be seen that if the temperature is up to 1, the permissible temperature is almost maintained. Therefore, if the distance between the top of the casing and the exhaust port is set within the range of 0.7 to 1.1 of the tube diameter, the tube wall temperature of the lamp tube can be maintained regardless of the presence or absence of a transparent member. It can be maintained within the temperature range, the required UV output can be obtained, and the lamp life will not be shortened due to devitrification of the lamp body.
Furthermore, it has been confirmed through experiments that the reflector is not deformed.

These results were similar for high-pressure discharge lamps of 90 W/cm or more.

(Example) An example of the present invention will be described with reference to the drawings. 1 and 2 show a first embodiment of the invention.

1 is a housing, and this housing 1 is formed in the shape of an elongated rectangular parallelepiped,
It has an opening 2 on the lower surface and an elongated groove 3 along the longitudinal direction on the upper surface. 4 is a tube-shaped high-pressure discharge lamp; 5 is a reflector having a concave cross-section and transmitting infrared rays and reflecting ultraviolet rays; An exhaust lower is located on the rear side and is arranged opposite to the high pressure discharge lamp 4 along its longitudinal direction.

This reflector 5 is formed by a pair of reflective members 8, 8, and has an upper end fixed to a support part 9a provided at the periphery of the upper surface groove 3 of the housing 1, and a lower end provided at the periphery of the lower surface opening 2 of the housing 1. It is supported and fixed to the support portion 9b, and communicates the exhaust lower with the groove portion 3. Reference numeral 10 denotes a transmitting member, and this transmitting member 10 is arranged so as to close the light projection opening 6 of the reflector 5. The transparent member 10 is engaged with a transparent plate 10a that blocks the inflow of gas and transmits at least ultraviolet rays, and a transparent member mounting portion consisting of a mouth-shaped rail provided at the end of the lower opening 2 of the housing 1, It is composed of a frame body 10b to which the transparent plate 10a is fixed.

The transmitting member 10 can be easily attached and detached from the device by moving it in the axial direction of the lamp 4 tube. The portion of the frame 10b that contacts the light-transmitting plate 10a has a protrusion 10e shape whose tip faces toward the top of the lamp. Note that this protrusion 10e is not necessarily required. 12.12 is a gas inlet provided in communication with the exhaust lower of the reflector 5;
．． 12 are provided on both sides of the reflector 5 with the light projection opening 6 interposed therebetween. In this embodiment, a frame body 10 for fixing a transparent plate 10a is used.
It is formed of a plurality of circular holes spaced apart from each other on the side surface of b. The gas flowing in from the gas inlet is controlled upward by the protrusion 10e of the frame 10b.

The high-pressure discharge lamp 4 is, for example, a metal halide lamp containing an iron-based component, and can emit not only ultraviolet rays but also visible light and infrared rays.

Further, the reflector 5 may be any material as long as it reflects ultraviolet rays and transmits infrared rays, for example, the inner surface of the base 5a (the side facing the high pressure discharge lamp 4) formed into a quadratic curved surface of borosilicate glass, for example, oxidized A high refractive index layer made of titanium (Tie), zirconium oxide (ZrO2), etc., and silica (
It is formed by depositing a multilayer interference thin film 5b in which 10 to 60 layers of low refractive index layers made of Si02), magnesium fluoride (MgF2), etc. are alternately laminated. The reflector 5 formed with this multilayer interference thin film 5b effectively reflects ultraviolet rays with a wavelength of 200 to 400 nm emitted from the high-pressure discharge lamp 4 in the direction of the projection aperture 6, and transmits infrared rays with a wavelength of about 700 nm or more. At the same time, it also allows some visible light to pass through.

The light-transmitting plate 10a includes, for example, an inner surface (the side facing the high-pressure discharge lamp 4) of a base body 10c made of quartz glass that transmits ultraviolet rays, such as zirconium oxide (Zr02),
, a high refractive index layer made of hafnium mide (HfO2), silica (Si02), magnesium fluoride (Mg
10 to 60 layers of low refractive index layers consisting of F2) etc.
A multilayer interference film 10d consisting of several layers is formed by vapor deposition. The light transmitting plate 10a on which the multilayer interference thin film 10 (l) is formed has a wavelength of 200 to 400 emitted from the high pressure discharge lamp 4.
It transmits ultraviolet light at 0 m and reflects visible light, and also reflects some infrared light.

Furthermore, gas flow ports 13a and 13b are formed on the side surface 1a and the top surface 1b of the housing 1 so as to be located on the back side of the reflector 5. The exhaust lower of the reflector 5 and the gas flow port 13b on the upper surface 1b of the housing 1 communicate with an exhaust means (not shown).

Then, the high pressure discharge lamp 4 has an arc length of 1 cm.
The power output is 90W or more, for example 120W, and the distance between the top of the tube of the lamp 4 and the exhaust lower of the reflector 5 is 0. It is .9.

The operation of this embodiment will be explained. When the light transmitting member 10 is removed, gas is taken in through the light projection opening 6. Further, when the transparent member 10 is attached, gas is taken in from the gas inlet 12.

The position of the lamp 4, that is, the distance between the top of the lamp tube 4 and the exhaust lower part of the reflector 5 is 0, which is the diameter of the lamp tube 4.
．． 9, regardless of the presence or absence of the light-transmitting member 10, ultraviolet rays can be irradiated well and the life of the reflector will not be shortened.

In addition, in this example, even after the exhaust air is determined with the transparent member attached, the exhaust air volume remains unchanged even if the transparent member is removed.
The change remains at 0.50 m3/min.

That is, for example, even if an exhaust means is set to the exhaust ff1i of 8 cm3/min, a transparent member is attached and used, and the transparent member is removed depending on the object to be irradiated, the exhaust air volume will be about 8.50 m3/min. The difference in ultraviolet light output is only about 5%, so there is no problem with using the device separately. Conversely, it is possible to eliminate the trouble of resetting the exhaust air volume.

What is shown in FIG. 6 shows a second embodiment of the present invention, and the same parts as in the first embodiment are denoted by the same reference numerals, and the explanation thereof will be omitted.

That is, in this second embodiment, the inflow ports 22, 2
2 is formed on substantially the same surface as the surface of the transparent plate 10a.

In this case, an experiment was conducted using the same lamp as in the first example under the same conditions, and almost the same results as in the first example were obtained. In addition, by forming the reflector 5 as a paraboloid and positioning the lamp at the focal point,
A wide light distribution can be obtained, and by forming the refractor 5 in an elliptical shape and positioning the lamp at one focal point, a focal light type can be obtained.

〔Effect of the invention〕

As detailed above, according to the present invention, the infrared attachment portion is provided so that the distance between the leeward side of the lamp tube and the exhaust port is within the range of 0.7 to 1.1 of the tube diameter. With this setting, the temperature of the tube wall of the lamp tube can be maintained within the appropriate range regardless of the presence or absence of a transparent member and without adjusting the exhaust means, preventing devitrification of the lamp tube or extreme drop in ultraviolet output. This can be effectively prevented and the deformation of the reflector can be prevented. That is, by using the ultraviolet irradiation device of the present invention, desired ultraviolet irradiation suitable for various objects to be irradiated can be performed satisfactorily by simply removing the ultraviolet transmitting member.

is a longitudinal sectional view of the same example, and Figures 3 and 4 are diagrams of the lamp tube body when the distance between the lamp and the reflector is changed in the ultraviolet irradiation device with and without the transmitting member attached and removed, respectively. FIG. 5 is a diagram showing the relationship between temperature and reflector temperature and exhaust air volume; FIG. 5 is a diagram showing the relationship between reflector temperature and reflector life.

FIG. 6 is a longitudinal sectional view showing the second embodiment of the ultraviolet irradiation device of the present invention, FIG. 7 is a diagram showing the relationship between the lamp body temperature and the ultraviolet output, and FIG. 8 is a diagram showing the relationship between the lamp body temperature and the ultraviolet output. FIG. 3 is a diagram showing the relationship with lamp life.

4...High pressure discharge lamp, 5...Reflector.

6...Light emission aperture, 7...Exhaust port.

11...Transmission member attachment part 12.12...Gas inlet Patent applicant Toshiba Electric Materials Corporation Agent Patent attorney Ono 1) Yoshihiro 1F'XI Figure 2 Figure 3 U/P: 8.4KW (+20W/m) Exhaust f
(m'min) 1st Fig. 340 Reflector temperature
figure

Claims (1)

[Claims] (1) A reflector with a concave cross section, which has a rectangular light projection opening on the lower surface and an exhaust port near the deepest part, and is coated with a multilayer interference film that transmits infrared rays and reflects ultraviolet rays; A straight pipe type with a power of 90 W or more per 1 cm of arc length, which is installed below the exhaust port so that the distance between the exhaust port and the top of the pipe body is within the range of 0.7 to 1.1 of the pipe diameter. a high-pressure discharge lamp; provided near the side of the light projection opening;
a transmitting member mounting portion for removably attaching a transmitting member that transmits ultraviolet light passing through the light transmitting aperture under the light transmitting aperture; when the transmitting member is attached to the transmitting member mounting portion; An ultraviolet irradiation device characterized by comprising: a gas inlet for flowing gas into the reflector from the vicinity; and exhaust means for forcibly exhausting gas around the lamp from the exhaust port.