JP2012195266A - Light irradiation device and long arc metal halide lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure which prevents, especially, the light emission side of the luminous tube of a metal halide lamp from being excessively cooled to cause freezing of an encapsulated metal during standby lighting, and raises the brightness vertically at the time of steady lighting, in a light irradiation device comprising a long arc metal halide lamp and a gutter-like reflection mirror surrounding the metal halide lamp and having a top opening, and in which cooling air flows from the front opening of the reflection mirror toward the top opening.SOLUTION: A belt-like thermal insulation film elongating in the axial direction is formed on the front opening side of a reflection mirror, on the outer surface of the luminous tube of a metal halide lamp.

Description

  The present invention relates to a light irradiation device and a long arc type metal halide lamp.

  Conventionally, in the printing industry and the electronics industry, as an ultraviolet light source for photochemical reaction equipment used for drying ink and paint, curing resin, or for exposing a liquid crystal substrate for a semiconductor substrate or a liquid crystal display. A long arc type metal halide lamp is used as an ultraviolet light source of an exposure apparatus to be used.

A conventional long arc type metal halide lamp 1 will be described with reference to FIG.
Sealing portions 3 are formed at both ends of the arc tube 2, and a pair of electrodes 4 and 4 are disposed in the arc tube 2.
The rear end portion 4a of the electrode 4 is cut so that the upper and lower portions have a flat surface shape, and has a substantially prismatic shape.
A flat spacer glass 5 made of quartz glass is embedded in the sealing portion 3, and a pair of (two) metal foils 6 a and 6 b are arranged on the upper and lower surfaces so as to sandwich the spacer glass 5. Yes.
Further, a glass holding cylinder 7 is disposed in the sealing portion 3, and the electrode 4 is inserted through the holding cylinder 7, thereby supporting the electrode 4.
An external lead 8 is connected to the rear ends of the metal foils 6a and 6b.
In order to radiate ultraviolet rays satisfactorily, the arc tube 2 is filled with a metal such as mercury, iron or thallium.

The structure of the light irradiation apparatus using such a metal halide lamp is known in Japanese Patent Application Laid-Open No. 2007-157583 (Patent Document 1) and Japanese Patent No. 2668832 (Patent Document 2), and the structure is shown in FIG. It is shown.
FIG. 5A is an explanatory view showing a state where the reflection mirror is opened.
FIG. 5B is an explanatory diagram of a state in which the reflection mirror is closed.
The light irradiation device includes a bowl-shaped reflection mirror 20 surrounding the metal halide lamp 1, and the reflection mirror 20 has a top opening 20a and a front opening 20b. The reflection mirror 20 is openable and closable. In the steady lighting mode in which the processing object is irradiated with ultraviolet light, the front opening 20b is opened as shown in FIG. In the standby lighting mode, as shown in FIG. 5B, the reflection mirror 20 is rotated to close the front opening 20b. In the standby lighting mode, the input power to the lamp is reduced from the viewpoint of power saving.

At the time of steady lighting shown in FIG. 5 (A), cooling air is flowed from below the reflecting mirror 20, passes around the lamp 1, cools it, and flows out from the top opening 20a.
Even in the standby lighting mode, the lamp is lit at a low power lower than the rated power. At this time, the front opening 20b of the reflecting mirror 20 is closed, and the reflecting mirror 20 is heated. End up. In order to protect the dielectric multilayer film constituting the reflecting surface of the reflecting mirror 20, it is necessary to cool it, and the cooling air is not stopped and the ventilation is maintained. At this time, as shown in FIG. 4 (B), the front opening 20b of the reflection mirror 20 is closed but not sealed, so that cooling air also flows from that portion and directly hits the lamp. It will be.
Further, depending on the heating state of the reflection mirror 20, the air volume may be increased rather than during steady lighting.
For these reasons, the lamp 1 is often in an overcooled state, and when the subsequent steady lighting mode is entered, the rise of illuminance is delayed, and the irradiation energy within a predetermined tact time is insufficient. The problem of insufficient UV treatment occurs. If this shortage is compensated, the processing time (tact time) will be prolonged.

JP 2007-157583 A Japanese Patent No. 2668832

  In view of the above-mentioned problems of the prior art, the present invention has a pair of electrodes inside the arc tube, a long arc type metal halide lamp containing a metal as a luminescent material, and a top opening that surrounds the metal halide lamp. In a light irradiation device in which cooling air flows from the front opening of the reflection mirror toward the top opening, even if the reflection mirror is closed during standby lighting, the long arc type metal halide lamp is a reflection mirror. It is intended to provide a structure that can quickly rise in illuminance during subsequent steady lighting without being supercooled by the cooling air.

In order to solve the above problems, a long arc type metal halide lamp in a light irradiation apparatus according to the present invention is an outer surface of the arc tube, and a belt-like heat retaining film extending in the axial direction is formed on the front opening side of the reflecting mirror. It is formed.
In addition, a reflective film extending in the axial direction of the arc tube is formed on the outer surface of the arc tube opposite to the heat retention film so as to face the heat retention film.
In addition, the reflective film is wider than the heat insulating film.

  According to the light irradiation apparatus of the present invention, since the belt-shaped heat insulating film is formed on the arc tube of the long arc type metal halide lamp incorporated in the light irradiation apparatus, the cooling air is kept in a state in which the reflection mirror is closed during standby lighting. Is prevented from overcooling until the lamp is overcooled. As a result, the illuminance rises quickly during subsequent steady lighting, and no processing time is lost.

Sectional drawing of the light irradiation apparatus of this invention. Sectional drawing of the long arc type metal halide lamp in FIG. The graph showing an experimental result. Sectional drawing of the conventional long arc type metal halide lamp. Sectional drawing of the conventional light irradiation apparatus.

FIG. 1 is an explanatory view of a light irradiation device of the present invention, and FIG. 2 is an explanatory view of a long arc type metal halide lamp incorporated in the light irradiation device of the present invention.
First, a long arc type metal halide lamp will be described with reference to FIG.
As shown in FIG. 2 (A), in the long arc type metal halide lamp 1 of the present invention, a strip-shaped heat insulating film 10 is formed on the outer surface of the arc tube 2 so as to extend in the axial direction.
In addition, a strip-like reflective film 11 is similarly formed on the outer surface of the arc tube 2 facing the heat insulating film 10 and opposite thereto so as to extend in the axial direction.
2B, which is a cross section of FIG. 2A, the width of the reflective film 11 is preferably larger than the width of the heat retaining film 10.
The light radiated upward from the arc tube 2 is reflected by the reflective film 11 and radiated to the lower light emitting side for effective use.
Other structures are the same as those of the conventional structure shown in FIG.

One specification of the long arc type metal halide lamp is as follows.
Light emission length: 1100mm, arc tube inner diameter: 22mm
Inclusion material: mercury 70 mg, mercury iodide 20 mg, iron 3 mg, thallium iodide
1 mg, magnesium iodide 2 mg, argon 3 kPa
Lamp input: 13.2 kW during irradiation, 8.8 kW during standby
Cooling air volume: 19 m ³ / min during steady lighting (irradiation), 9 m ³ / min during standby lighting
The heat insulating film 10 is a black ceramic coating film.
Specifically, the composition is composed of 53% silica, 5% alumina, 19% phosphoric acid, 23% copper chromate, and 70% aqueous solution of the ceramic composition is screen printed so that the thickness is about 100 μm. It is formed, dried and fired.

In addition, as another example of the heat retaining film 10, an ultraviolet reflecting film composed of silica particles and alumina particles may be used.
The reflective film has an ultraviolet reflectance of about 60%, and the remaining 40% of the light is scattered in the ultraviolet reflective film, thereby being absorbed and heating the arc tube.

As shown in FIG. 1, the long arc type metal halide lamp having the above configuration is incorporated into a light irradiation device as follows.
In the long arc type metal halide lamp, the heat insulating film 10 on the outer surface thereof is arranged toward the light emitting side. At this time, the reflective film 11 is disposed on the side opposite to the light emitting side.
As shown in FIGS. 1A and 1B, in the light irradiation device, the reflecting mirror 20 is opened (A) in the steady lighting mode and closed (B) in the standby lighting mode, as in the conventional example shown in FIG. is there.

  In this way, in the light irradiation apparatus incorporating the long arc type metal halide lamp 1 of the present invention, the reflection mirror 20 is cooled particularly in the state where the reflection mirror 20 is closed in the standby lighting mode shown in FIG. Even if the cooling air is flown, the heat insulating film 10 formed below the arc tube 2 absorbs the light emitted from the lamp 1 and becomes high temperature, and the cooling air hits the temperature of the arc tube 2 to decrease. The light emitting side part can be heated and does not reach a supercooled state, and the metal sealed in the arc tube can be sufficiently evaporated while in the standby lighting mode, and the steady lighting mode is set. When this happens, the rise of illuminance can be accelerated.

In order to verify the effect of the present invention, an illuminance measurement experiment was performed at a wavelength of 365 nm on the irradiated surface.
This is the graph shown in FIG. 3, where the vertical axis represents the relative value of illuminance and the horizontal axis represents the irradiation time (seconds) in the steady lighting mode. The long arc type metal halide lamp used in this experiment is not provided with the reflective film 11.
In the conventional lamp that does not have the heat insulation film, the illuminance gradually increases after switching to the steady lighting mode, whereas in the lamp according to the present invention having the heat insulation film, the illuminance is almost vertical immediately after switching to the steady lighting mode. It can be seen that the illuminance is maintained almost constant over the entire irradiation time.

  As described above, in the present invention, the outer surface of the arc tube of the long arc type metal halide lamp, and by forming a belt-like heat retaining film extending in the axial direction on the front opening side of the reflection mirror, When the metal halide lamp is incorporated in the light irradiation device, it is possible to prevent the light emission side from being overcooled by the cooling air during standby lighting, and the light emitting metal in the arc tube is evaporated even in the standby lighting mode. The maintained state can be maintained. Therefore, when switching to the steady lighting mode, the illuminance rises instantaneously and effective light irradiation is performed.

DESCRIPTION OF SYMBOLS 1 Long arc type metal halide lamp 2 Light emission tube 3 Sealing part 4 Electrode 5 Spacer glass 6a, 6b Metal foil 7 Holding cylinder 8 External lead 10 Heat retention film 11 Reflective film 20 Reflective mirror 20a Top opening 20b Front opening

Claims (6)

A long arc type metal halide lamp having a pair of electrodes inside the arc tube and containing a metal as a luminescent material, and a bowl-shaped reflection mirror surrounding the metal halide lamp and having a top opening, the front of the reflection mirror In the light irradiation device in which cooling air flows from the opening toward the top opening,
A light irradiating apparatus characterized in that a strip-shaped heat insulating film extending in the axial direction is formed on the outer surface of the arc tube of the metal halide lamp and on the front opening side of the reflecting mirror.   2. The light irradiation device according to claim 1, wherein a reflection film extending in the axial direction of the arc tube is formed on the outer surface of the arc tube opposite to the heat retention film so as to face the heat insulation film. .   The light irradiation apparatus according to claim 2, wherein the reflective film is wider than the heat insulating film.   The light irradiation apparatus according to claim 1, wherein the metal halide lamp is turned on by switching between a steady lighting mode and a standby lighting mode. In a long arc type metal halide lamp having a pair of electrodes inside the arc tube and containing a metal as a luminescent material,
A long arc type metal halide lamp characterized in that a strip-shaped heat insulating film extending in the axial direction is formed on the outer surface of the arc tube. The long film according to claim 5, wherein a reflection film that extends in an axial direction of the arc tube is formed on an outer surface of the arc tube opposite to the heat insulation film so as to face the heat insulation film. Arc type metal halide lamp.

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