JP6557011B2 - Excimer lamp - Google Patents

Description

  The present invention relates to an excimer lamp that discharges and emits light by dielectric barrier discharge or capacitively coupled high-frequency discharge.

  Excimer lamps form an arc tube with a sealed space made of a dielectric material that transmits ultraviolet light, such as quartz glass, and mixed with a rare gas such as xenon or a mixture of rare gas and halogen gas in the sealed space. Gas is sealed as a discharge gas. When a high voltage of several kV is applied between the internal and external electrodes arranged inside and outside the sealed space, dielectric barrier discharge or capacitively coupled high-frequency discharge occurs in the discharge space, and ultraviolet rays are emitted outside the arc tube. (See, for example, Patent Document 1).

  Large excimer lamps have a great degree of freedom in the shape and structure of arc tubes and electrodes. On the other hand, the small excimer lamp being developed by the present applicant has an outer diameter of the arc tube, that is, an outer diameter of the outer tube in the range of 5 (mm) to 20 (mm), and has a bottomed cylindrical inner tube. And a bottomed cylindrical outer tube which is connected to the inner tube integrally with the inner tube by reducing the diameter of the opening side and forms a sealed space with the inner tube, and discharges into the sealed space. Gas is sealed. Then, by applying a high voltage (hereinafter, applied voltage) between the outer electrode disposed on the outer peripheral surface side of the outer tube of the arc tube and the inner electrode inserted and disposed on the inner peripheral surface side of the inner tube, a sealed space is obtained. Among them, dielectric barrier discharge is generated in a range in which the outer electrode and the inner electrode face each other in the excimer lamp radial direction. The ultraviolet rays generated by the discharge are radiated to the outside from the bottom of the outer tube, and irradiate the surface to be irradiated which is spaced apart from the bottom of the outer tube by 7 (mm) or more and 15 (mm) or less in the axial direction of the excimer lamp. Is done.

  Such a small excimer lamp has the advantage that it can be arranged in a very small space compared to a conventional large excimer lamp. In addition to the small size of the excimer lamp, the excimer lamp and the irradiated surface Therefore, it is not appropriate to provide a lens such as a convex lens at the bottom of the outer tube, and there is a drawback that the ultraviolet illuminance distribution on the irradiated surface is not suitable.

  In the excimer lamp described in Patent Document 2, a condensing lens is provided on the window member (that is, the outer tube bottom) in order to increase the light emission luminance. However, the excimer lamp has a short distance between the excimer lamp and the irradiated surface. No consideration is given to the ultraviolet illuminance distribution on the irradiated surface.

JP-A-6-275242 JP-A-6-338301

  SUMMARY OF THE INVENTION An object of the present invention is to realize efficient irradiation of ultraviolet rays with a suitable distribution on a surface to be irradiated in a small excimer lamp arranged close to the surface to be irradiated.

In order to solve the above-mentioned problem, an excimer lamp according to claim 1 is provided with a bottomed cylindrical outer tube having a diameter of 5 (mm) or more and 20 (mm) or less and an inner tube disposed inside the outer tube. A bottom cylindrical inner tube, a sealed space in which a discharge gas is sealed between the outer tube and the inner tube, an outer electrode disposed on the outer surface of the outer tube, and a foil sealed inside the inner tube In an excimer lamp that irradiates the irradiated surface facing the bottom of the outer tube with the inner electrode in the shape of ultraviolet rays, the light emitting surface that irradiates the irradiated surface with ultraviolet rays, which is a plane along the lamp radial direction On the bottom outer surface of the outer tube, and an outer electrode on at least a part of the outer surface other than the light emitting surface, the outer diameter R of the outer tube being 5 (mm) or more and 20 (mm) or less, The distance L in the lamp axis direction between the outer tube bottom and the irradiated surface is 7 (mm) or more and 15 (mm) or less. The axial length A (mm) of the sealed space where the outer electrode and the inner electrode face each other in the lamp radial direction is the length in the lamp axial direction from the inner tube bottom side end of the inner electrode to the irradiated surface. For B (mm), the range of the following conditional expression is adopted.
B / 1.07 ≦ A ≦ B / 0.11

The excimer lamp according to claim 2 is the excimer lamp according to claim 1, wherein the irradiated surface has a circular shape centered on the axis of the excimer lamp, and the irradiated surface has a diameter RW (mm). On the other hand, the outer tube outer diameter R (mm) is in the range of the following conditional expression.
0.25 × RW ≦ R ≦ RW

The excimer lamp according to claim 3 is the excimer lamp according to claim 1 or 2, wherein the ultraviolet rays irradiated to the irradiated surface are ultraviolet rays including 172 (nm), and the outer electrode is an aluminum film. It is characterized by being.

The excimer lamp according to claim 4 includes a bottomed cylindrical outer tube, a bottomed cylindrical inner tube disposed inside the outer tube, an outer electrode disposed on an outer surface of the outer tube, An excimer lamp including a foil-like inner electrode sealed inside a tube, and having a light emitting surface that is a flat surface along the radial direction of the lamp on the outer surface of the bottom of the outer tube, and other than the light emitting surface The outer surface has an outer electrode, and the irradiated surface opposite to the light emitting surface is irradiated with ultraviolet rays.

  ADVANTAGE OF THE INVENTION According to this invention, the small excimer lamp arrange | positioned in the vicinity of the to-be-irradiated surface which can irradiate an to-be-irradiated surface efficiently with suitable distribution can be provided.

It is sectional drawing which passes along the axis line of the excimer lamp by this invention. It is sectional drawing which follows the CC line of FIG. It is sectional drawing of the excimer lamp of FIG. 1, and a to-be-irradiated surface. It is a figure which shows the experimental result of ultraviolet illuminance distribution. It is a figure which shows the experimental result of ultraviolet illuminance.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show an embodiment of an excimer lamp according to the present invention. FIG. 1 is a cross-sectional view taken along the axis of the excimer lamp, and FIG. 2 is a cross-sectional view taken along the line CC in FIG. .

  An excimer lamp (hereinafter referred to as a lamp) includes an arc tube 3 including an outer tube 1 and an inner tube 2 each having a bottomed tubular shape (substantially U-shaped in the lamp axis direction) made of a dielectric material such as quartz glass, and an inner tube 2. The inner tube bottom 201 at the tip of the tube, the outer tube bottom 101 at the tip of the outer tube 1, the light emission surface 4 which is a plane outside the outer tube bottom 101, and the outer surface of the outer tube 1 excluding the light emission surface 4 are disposed. The outer electrode 5, the inner electrode 6 disposed inside the inner tube 2, the outer feeder 501 electrically connected to the outer electrode 5, and the inner feeder 601 electrically connected to the inner electrode 6. On the rear end side of the arc tube 3, the outer tube 1 is constituted by a sealing portion 7 having a reduced diameter and welded to the inner tube 2.

  The arc tube 2 forms a sealed space 8 having a donut-shaped cross section in the lamp radial direction between the outer tube 1 and the inner tube 2, and in this sealed space 8, a rare gas such as Xe, or a rare gas and a halogen gas are included. Are mixed as a discharge gas, and the diameter of the arc tube 3 is 5 (mm) or more and 20 (mm) or less.

  The inner tube 2 is disposed inside the outer tube 1 so that the inner tube bottom 201 does not contact the outer tube 1. The inner tube 2 has a foil-shaped inner electrode 6 having a width of 1.5 (mm) or more and 3.0 (mm), and the inner electrode 6 is welded to the inner tube 1 to form a sealed space 8. It is embedded in the inner tube 2 without being exposed. The inner electrode 6 is welded to the inner power supply line 601, and the welded portion is embedded in the inner tube 2 in the vicinity of the sealing portion 7.

  The inner surface of the outer electrode 5 is a conductive reflective film or sheet having a property of reflecting ultraviolet rays generated in the sealed space 8 toward the sealed space 8, and may be various metal films. The outer electrode 5 is preferably an aluminum film, for example, in the case of reflecting 172 (nm) ultraviolet rays.

  When a high frequency high voltage of 3 to 12 (kV) is applied between the outer electrode 5 and the inner electrode 6 from the power supply unit (not shown) via the outer feeder line 501 and the inner feeder line 601, the sealed space 8 Among these, dielectric barrier discharge (capacitive coupling type high frequency discharge) occurs between the outer tube 1 and the inner tube 2 which are dielectrics in a range where the outer electrode 5 and the inner electrode 6 are opposed to each other in the lamp radial direction. Since the sealed space 8 is filled with a rare gas or a mixed gas of a rare gas and a halogen as a discharge gas, ultraviolet light, that is, light having a wavelength corresponding to the rare gas and the halogen is generated in the sealed space 8 by the dielectric barrier discharge. . The ultraviolet rays are guided in the lamp axis direction by reflection of the inner surface of the outer electrode 5, the fiber effect of the outer tube 1 and the inner tube 2, and are emitted from the light emitting surface 4 toward the lamp axis direction. In particular, by arranging the outer electrode 5 up to the portion where the outer tube 1 has a reduced diameter, the outer electrode 5 on the outer surface of the outer diameter portion of the outer tube reflects the ultraviolet rays radiated to the lamp axial direction sealing portion side. Since the light is guided to the light emitting surface side, the ultraviolet rays can be radiated from the light emitting surface 4 toward the lamp axis direction more efficiently.

  FIG. 3 is a cross-sectional view of the lamp of FIG.

The irradiated surface 9 irradiated with ultraviolet rays has a circular shape centered on the lamp axis, and the outer diameter RW of the irradiated surface 9 is 1 with respect to the outer diameter R of the outer tube 1 (outer tube bottom 101). It is more than double and less than 4 times. The lamp-axis direction distance L between the irradiated surface 9 and the light emission surface 4 (the flat surface of the outer tube bottom 101) is 7 (mm) or more and 15 (mm) or less, and the light emission surface 4 is on the lamp axis direction side. The emitted ultraviolet light is irradiated to the irradiated surface 9.

In such a lamp, the ultraviolet illuminance at the central portion of the irradiated surface 9 is smaller than the ultraviolet illuminance in other regions, and there is a tendency that a suitable ultraviolet irradiation distribution cannot be obtained. In the present embodiment, the inventor of the present invention describes a space in which discharge occurs in the sealed space 8, that is, the length A in the lamp axis direction of the space in which the outer electrode 5 and the inner electrode 6 face each other in the lamp radial direction, and the inner electrode 6. From the relationship between the lamp tube direction distance B between the inner tube side end and the irradiated surface 9, a decrease in the minimum ultraviolet illuminance value with respect to the maximum ultraviolet illuminance value of the irradiated surface 9 is suppressed, and the ultraviolet illuminance distribution is suitable. It was found that (1) can be determined.
B / A ≧ 0.11 (1)

On the other hand, when the lamp axial direction distance B is increased, the ultraviolet rays generated by the discharge are attenuated, and the irradiated surface 9 cannot be irradiated with the necessary ultraviolet rays. Since the amount of ultraviolet rays radiated in the lamp axis direction is greatly affected by the length A in the lamp axis direction, it has been found that the relational expression (2) that can suppress the attenuation of the ultraviolet rays can be defined.
B / A ≦ 1.07 (2)

From the relational expression (1) and the relational expression (2), the lamp axis direction length A is set so as to satisfy the relational expression (3) with respect to the lamp axis direction distance B. Irradiation can be performed efficiently with a good distribution.
B / 1.07 ≦ A ≦ B / 0.11 (3)

  Hereinafter, a lamp that satisfies the above-described expression (1) will be described as a first embodiment.

  The outer diameter L of the outer tube 1 is 10.5 (mm) and the wall thickness is 1 (mm), and an aluminum film is provided as an outer electrode 5 on the outer surface excluding the light emitting surface 4. The inner electrode 6 is a molybdenum foil having a width of 2 (mm), and the inner tube 2 having a thickness of 1 mm is buried in the inner tube 2 by being melted and deformed, and is welded to the inner feeder 601 in the vicinity of the sealing portion 7. . The outer diameter RW of the irradiated surface 9 is 20 (mm). The lamp in the space where the outer electrode 5 and the inner electrode 6 are opposed to each other in the lamp radial direction when the distance L in the lamp axial direction between the light emitting surface 4 and the irradiated surface 9 is 7 (mm) or more and 15 (mm) or less. Regarding the axial length A and the lamp axial distance B between the inner tube bottom side end of the inner electrode 6 and the irradiated surface 9, the value of B / A was varied in the range of 0.05 to 1.00. A prototype lamp was produced, turned on with an applied voltage of 5 (kV), and the ultraviolet illuminance distribution in the irradiated surface 9 was measured. FIG. 4 is a diagram showing the minimum ultraviolet illuminance value in the irradiated surface 9 when the maximum ultraviolet illuminance value of each prototype lamp is 100 (%) in the ultraviolet illuminance distribution of each prototype lamp.

  From FIG. 4, when the value of B / A is 0.11 or more, the minimum illuminance value is extremely small with respect to the maximum illuminance value, that is, no deterioration of the illuminance distribution in the irradiated surface 9 is observed. It was. As a result, it is apparent that the ultraviolet illuminance distribution in the irradiated surface 9 is suitable because the value of B / A is 0.11 or more.

  Next, a lamp that satisfies the above formula (2) will be described as a second embodiment.

  With respect to the lamp axial distance B, a prototype lamp was produced in which the value of B / A was varied from 0.1 to 2.0. Since other conditions are the same as those in the first embodiment, a description thereof will be omitted. The applied voltage was turned on at 5 (kV), and the ultraviolet illuminance of the entire irradiated surface 9 was measured. FIG. 5 summarizes the ultraviolet illuminance of each prototype lamp when the ultraviolet illuminance of the prototype lamp having a B / A value of 0.1 is 100%.

  From FIG. 6, when the value of B / A was 1.07 or less, an extreme decrease in ultraviolet illuminance on the irradiated surface was not observed. That is, it is clear that the value of B / A is 1.07 or less that can suppress the decrease in ultraviolet illuminance in the irradiated surface.

DESCRIPTION OF SYMBOLS 1 Outer tube 2 Inner tube 3 Light emission tube 4 Light emission surface 5 Outer electrode 6 Inner electrode 7 Sealing part 8 Sealed space 9 Irradiated surface 101 Outer tube bottom part 201 Inner tube bottom part 501 Outer feeder line 601 Inner feeder line

Claims (3)

A bottomed cylindrical outer tube formed by melting and deforming a dielectric material that has a light emission surface at the bottom of the outer tube and transmits ultraviolet rays;
The inner tube bottom portion is arranged inside the outer tube so as not to contact the outer tube bottom portion, and includes a bottomed cylindrical inner tube formed by melting and deforming a dielectric material that transmits ultraviolet rays,
An arc tube that forms a sealed space between the outer tube and the inner tube;
An outer electrode that reflects ultraviolet rays, provided on at least a part of the outer surface of the outer tube other than the light emitting surface;
A foil-shaped inner electrode embedded without being exposed to the sealed space by welding the inner tube;
The outer diameter R of the outer tube is 5 (mm) or more and 20 (mm) or less,
When the lamp axial direction distance L between the outer tube bottom and the irradiated surface facing the outer tube bottom is 7 (mm) or more and 15 (mm) or less,
The lamp axis direction length A (mm) of the sealed space where the outer electrode and the inner electrode face each other in the lamp radial direction is:
With respect to the lamp axis direction length B (mm) from the inner tube bottom side end of the inner electrode to the irradiated surface,
In excimer lamps within the range of the following conditional expression:
The ultraviolet rays generated in the sealed space are
Induced in the axial direction of the lamp by reflection of the inner surface of the outer electrode;
Induced in the direction of the lamp axis to the bottom of the outer tube by a fiber effect that penetrates the dielectric material constituting the outer tube;
And is guided in the axial direction of the lamp to the bottom of the inner tube by a fiber effect that penetrates the dielectric material constituting the inner tube ,
An excimer lamp emitting from the light emitting surface to the outside of the arc tube in the lamp axial direction.
B / 1.07 ≦ A ≦ B / 0.11 The excimer lamp according to claim 1,
The irradiated surface is a circular shape having a center on the axis of the excimer lamp,
The excimer lamp, wherein the outer tube outer diameter R (mm) is in the range of the following conditional expression with respect to the diameter RW (mm) of the irradiated surface.
0.25 × RW ≦ R ≦ RW The excimer lamp according to claim 1 or 2,
The ultraviolet rays are ultraviolet rays including 172 (nm),
The excimer lamp is characterized in that the outer electrode is an aluminum film.

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