JP7135605B2 - Barrier discharge lamp, UV irradiation unit and UV irradiation device - Google Patents

Description

Embodiments of the present invention relate to a barrier discharge lamp, an ultraviolet irradiation unit, and an ultraviolet irradiation device.

2. Description of the Related Art Conventionally, barrier discharge lamps are known which are used for the purpose of cleaning and modifying substrates. In a barrier discharge lamp, a dielectric barrier discharge is generated by connecting a spiral internal electrode arranged inside a dielectric arc tube and an external electrode arranged outside the arc tube to an AC power supply. It emits ultraviolet light having a specific wavelength depending on the gas contained inside the arc tube. The emitted ultraviolet light is reflected by a reflecting film provided on the inner surface of the arc tube so as to irradiate a predetermined portion.

JP 2013-211164 A

In the barrier discharge lamp as described above, for example, the reflective film may be worn or peeled off due to displacement of the internal electrodes, and the illuminance of the emitted ultraviolet light may be reduced.

A problem to be solved by the present invention is to provide a barrier discharge lamp, an ultraviolet irradiation unit, and an ultraviolet irradiation apparatus that can suppress defects due to abrasion or peeling of a reflective film.

A barrier discharge lamp of an embodiment includes a cylindrical arc tube, an internal electrode, and a reflective film. A barrier discharge lamp performs barrier discharge between an internal electrode provided inside an arc tube and an external electrode provided near the arc tube. The arc tube is filled with gas and transmits ultraviolet light. The internal electrode is arranged inside the arc tube, and the spiral conductor extends in the length direction of the arc tube. The reflective film is provided on the inner surface of the arc tube and reflects ultraviolet light to the inside of the arc tube. The arc tube has a plurality of recesses for restricting the movement of the internal electrodes in a portion different from the reflective film . The diameter d [mm] of the recess and the wire diameter D [mm] of the internal electrode have a relationship of d≦10D. The external electrode is provided on the outer surface side of the arc tube corresponding to the inner surface provided with the reflective film.

According to the present invention, it is possible to suppress problems caused by wear or peeling of the reflective film.

1 is a plan view showing a barrier discharge lamp according to an embodiment; FIG. 2 is a cross-sectional view taken along line A-A' in FIG. 1; FIG. FIG. 5 is a diagram for explaining changes in irradiation characteristics according to the circumferential angle of the reflective film; It is a figure for demonstrating the difference of the illuminance characteristic based on the shape of a recessed part. It is a figure which shows the outline|summary of an evaluation test. It is a figure which shows the result of the evaluation test in the case of no recessed part. It is a figure which shows the result of the evaluation test in the case with a recessed part. It is a figure which shows the ultraviolet irradiation device which has an ultraviolet irradiation unit which concerns on embodiment.

A barrier discharge lamp 1 according to an embodiment described below includes a cylindrical arc tube 2 , an internal electrode 3 , and a reflective film 5 . The barrier discharge lamp 1 performs barrier discharge between an internal electrode 3 provided inside the arc tube 2 and an external electrode 6 provided near the arc tube 2 . The arc tube 2 is filled with gas and transmits ultraviolet light. The internal electrode 3 is arranged inside the arc tube 2 and a spiral conductor extends in the length direction of the arc tube 2 . The reflective film 5 is provided on the inner surface 2 a of the arc tube 2 and reflects ultraviolet light to the inside of the arc tube 2 . The light-emitting tube 2 has a plurality of recesses 4 for restricting movement of the internal electrodes 3 in portions different from the reflective film 5 . The diameter d [mm] of the recess 4 and the wire diameter D [mm] of the internal electrode 3 have a relationship of d≦10D.

Further, the inner surface 4a of the concave portion 4 according to the embodiment described below protrudes inside the arc tube 2 and contacts the internal electrode 3. As shown in FIG.

Further, the diameter d [mm] according to the embodiment described below and the pitch P [mm] of the internal electrodes 3 in the axial direction of the arc tube 2 have a relationship of d≦P.

Further, the external electrode 6 according to the embodiment described below is provided on the outer surface 2b side of the arc tube 2 corresponding to the inner surface 2a on which the reflective film 5 is provided. The external electrode 6 is a heat dissipation block made of aluminum or stainless steel.

Moreover, the ultraviolet irradiation unit 10 according to the embodiment described below includes the barrier discharge lamp 1 and the external electrode 6 .

Moreover, the ultraviolet irradiation device 100 according to the embodiment described below includes the ultraviolet irradiation unit 10 and a housing section 50 that houses the ultraviolet irradiation unit 10 .

A barrier discharge lamp 1 according to an embodiment described below includes a cylindrical arc tube 2 , an internal electrode 3 , a reflective film 5 and an external electrode 6 . The arc tube 2 is filled with gas and transmits ultraviolet light. The internal electrode 3 is arranged inside the arc tube 2 and has a spiral conductor extending in the axial direction of the arc tube 2 . The reflective film 5 is provided on the inner surface 2 a of the arc tube 2 and reflects ultraviolet light to the inside of the arc tube 2 . The external electrode 6 is provided on the outer surface 2b side of the arc tube 2 corresponding to the inner surface 2a on which the reflective film 5 is provided. The light-emitting tube 2 has a plurality of recesses 4 for restricting movement of the internal electrodes 3 in portions different from the reflective film 5 . The diameter d [mm] of the recess 4 and the wire diameter D [mm] of the internal electrode 3 have a relationship of d≦10D.

Embodiments according to the present invention will be described below with reference to the drawings. It should be noted that the embodiments shown below do not limit the technology disclosed by the present invention.

[Embodiment]
FIG. 1 is a plan view showing a barrier discharge lamp according to an embodiment, and FIG. 2 is a sectional view taken along line AA' of FIG. As shown in FIGS. 1 and 2, the barrier discharge lamp 1 according to the embodiment has an arc tube 2, internal electrodes 3, and a reflective film 5. As shown in FIG. In addition, barrier discharge is performed between the external electrode 6 provided near the barrier discharge lamp 1 . The term “nearby” as used herein is not limited to the case where the barrier discharge lamp 1 and the external electrode 6 are provided in contact with each other. including cases where In this embodiment, the external electrode 6 is provided in the vicinity of the barrier discharge lamp 1. However, the barrier discharge lamp 1, more specifically, the configuration in which the arc tube 2 and the external electrode 6 are combined is referred to as the "barrier discharge lamp 1". It may also be referred to as a "discharge lamp".

1 and 2 show a three-dimensional orthogonal coordinate system including the Z-axis with the irradiation direction as the positive direction, in order to facilitate the understanding of the explanation.

The arc tube 2 is a cylindrical member that transmits ultraviolet light. As a material of the arc tube 2, for example, synthetic quartz having a high vacuum ultraviolet transmittance with a wavelength of 200 [ nm ] or less is exemplified. Both ends of the arc tube 2 in the tube axial direction (X-axis direction) are held by sealing members having a stem structure and are airtightly sealed. The arc tube 2 can have, for example, a length of 750 [ mm ] in the axial direction and an inner diameter of 40 [ mm ] .

A gas is sealed inside the arc tube 2 . The gas is, for example, 80 to 200 [ kPa ] xenon gas. The gas can include, for example, one of krypton, xenon, argon, neon, or the like, or a combination of two or more. Additionally, the gas may optionally include, for example, a halogen gas. The arc tube 2 can emit ultraviolet light (excimer light) having a specific peak wavelength according to the type of gas enclosed.

The internal electrode 3 is arranged inside the arc tube 2 . The internal electrode 3 is a spiral conductor extending in the axial direction of the arc tube 2 . The internal electrodes 3 are made of a material containing tungsten, for example. Specifically, 50% or more of all components of the internal electrode 3 are tungsten . In particular, if doped tungsten obtained by adding potassium or the like to tungsten is applied as the internal electrode 3, higher dimensional stability can be obtained. For example, the internal electrode 3 can have a wire diameter D of 0.8 [ mm ] and a winding diameter (outer diameter) of 38 [ mm ] .

The reflective film 5 is provided on the inner surface 2 a of the arc tube 2 and reflects ultraviolet light to the inside of the arc tube 2 . As a material of the reflective film 5, for example, silica is exemplified. Moreover, the reflective film 5 is not limited to silica, and may be made of a material containing ultraviolet scattering particles such as alumina. The reflective film 5 is arranged so that the angle θ 1 in the circumferential direction of the arc tube 2 is, for example, 180° or more .

The reflective film 5 can change the peak value of the ultraviolet illuminance and the integrated amount of light according to the circumferential angle θ1 of the arc tube 2 . FIG. 3 is a diagram for explaining changes in irradiation characteristics according to the angle of the reflective film in the circumferential direction. As shown in FIG. 3, the peak value of the ultraviolet illuminance increases as the circumferential angle θ1 of the arc tube 2 increases. On the other hand, the larger the angle θ1, the smaller the emission area, so the integrated light amount increases to the maximum value and then decreases. In particular, in applications such as surface modification or photo-dry cleaning in which the integrated amount of light is an important index, the angle θ1 can be in the range of 200° to 250° .

The external electrode 6 is provided on the outer surface 2b side of the arc tube 2 corresponding to the inner surface 2a of the arc tube 2 on which the reflective film 5 is provided. The external electrode 6 also serves as a heat dissipation block for dissipating the heat generated by the barrier discharge lamp 1, and can be made of aluminum or stainless steel, for example. In addition, a flow path for circulating a liquid or gaseous coolant may be provided inside the external electrode 6 to further improve heat dissipation. The external electrode 6 and the arc tube 2 may be in contact with each other or may be separated from each other, but if the external electrode 6 and the arc tube 2 are brought into contact with each other, heat dissipation can be enhanced. In the example shown in FIG. 2, the circumferential angle of the inner surface 2a of the arc tube 2 in contact with the reflective film 5 and the circumferential angle of the outer surface 2b of the arc tube 2 covered with the external electrode 6 are different from each other. Although illustrated as being different, they may be the same without being limited to this. Further, in the example shown in FIG. 2, the angle θ2 of the external electrodes 6 in the circumferential direction is, for example, 238 [ ° ] , but it is not limited to this. The angle θ2 of the external electrodes 6 in the circumferential direction can be in the range of 180 [ ° ] to 330 [ ° ] , for example.

Here, a conventional barrier discharge lamp will be described. In conventional barrier discharge lamps, the internal electrodes are supported only at both axial ends of the arc tube. Therefore, in the central portion in the tube axis direction, the internal electrodes may be displaced due to, for example, vibration due to an external force or the weight of the internal electrodes. At this time, for example, if the displaced internal electrode comes into contact with the reflective film, the reflective film may be worn or peeled off, causing problems such as a decrease in illuminance.

Therefore, in the barrier discharge lamp 1 according to the embodiment, the arc tube 2 has a plurality of recesses 4 . That is, in the barrier discharge lamp 1 according to the embodiment, as shown in FIG. 2, the inner surface 4a of the concave portion 4 protrudes inside the arc tube 2 and abuts on the internal electrode 3. As shown in FIG. As a result, the movement of the internal electrode 3 is restricted not only at both ends in the tube axial direction, but also at a plurality of locations in the central portion. Or peeling is suppressed. The internal electrode 3 may be in contact with the reflective film 5 or may be separated therefrom.

Further, the concave portion 4 is provided in a portion different from the reflective film 5 . As a result, it is possible to prevent the reflective film 5 from being peeled off or damaged due to the formation of the concave portion 4 .

Further, the diameter d [mm] of the concave portion 4 and the wire diameter D [mm] of the internal electrode 3 have a relationship of d≦10D . Here , the "diameter d of the recess 4" is the value when the width in the tube axis direction (X-axis direction) at the outer edge of the recess 4 in contact with the outer surface 2b of the arc tube 2 is maximum. If d>10D, the area for deforming the arc tube 2 when forming the concave portion 4 becomes large, so that the internal electrodes 3 are deformed and the pitch P of the internal electrodes 3 becomes uneven, which is undesirable. . Further, if d>10D, the area for deforming the arc tube 2 becomes large, and the process of deforming the arc tube 2 takes time, which is not desirable. Therefore, it is desirable that d≦10D.

Further, the diameter d [mm] of the concave portion 4 and the pitch P [mm] of the internal electrodes 3 in the axial direction of the arc tube 2 preferably have a relationship of d≦P. This point will be described with reference to FIG.

FIG. 4 is a diagram for explaining the difference in illuminance characteristics based on the shape of the recess. (a) shows an example when d≤P, and (b) shows an example when d>P, which corresponds to the B-B' sectional view of the barrier discharge lamp 1 shown in FIG.

The concave portion 4 scatters the ultraviolet light emitted from inside the arc tube 2 . As shown in (b), when the diameter d [mm] of the concave portion 4 increases, the area in which the ultraviolet light is scattered increases, which may reduce the ultraviolet illuminance with which the object is irradiated. Therefore, by forming the concave portion 4 having a relationship of d≦P as shown in FIG. If the diameter d [mm] of the concave portion 4 is too small, the amount of deformation of the arc tube 2 due to the formation of the concave portion 4 may locally increase, and a through hole may be formed in the concave portion 4 . Therefore, it is preferable to form the concave portion 4 so that D<d≦P, for example.

[Evaluation test]
A vibration test was performed using a prototype of the barrier discharge lamp, and the difference in irradiation characteristics due to the presence or absence of the concave portion 4 was evaluated. Figure 5 shows the outline of the evaluation test. In addition, the vibration test was performed based on JISZ0232. The illuminance characteristics (UV illuminance change rate) and electrical characteristics (current change rate) before and after the vibration test were compared, and based on the measurement error in the preliminary test, a change rate of 2 [ % ] or less was judged to be satisfactory. Also, the number of tests was n=3p.

FIG. 6 shows the results of the evaluation test without the concave portion 4, and FIG. 7 shows the result of the evaluation test with the concave portion 4. As shown in FIG. As shown in FIG. 6, in the barrier discharge lamp without the concave portion 4, the rate of change in the illuminance characteristics and the electrical characteristics before and after the test for all of Samples 1 to 3 greatly exceeded 2%. Delamination was suggested as a problem. On the other hand, as shown in FIG. 7, in the barrier discharge lamp having the concave portion 4, the rate of change before and after the test of the illuminance characteristics and electrical characteristics of all samples 4 to 6 remained below 2 [ % ]. The improvement effect was confirmed by

[Ultraviolet irradiation device]
FIG. 8 is a diagram showing an ultraviolet irradiation device having an ultraviolet irradiation unit according to the embodiment. (a) is a diagram viewed from the tube axis direction (Y-axis direction), and (b) is a diagram viewed from the X-axis direction. As shown in FIG. 8 , the ultraviolet irradiation device 100 according to the embodiment has a housing member 50 and a lighting device 60 . One or more ultraviolet irradiation units 10 are housed in the housing member 50 . The containing member 50 is an example of a containing portion.

The ultraviolet irradiation unit 10 has a barrier discharge lamp 1 and an external electrode 6 . When the barrier discharge lamp 1 , more precisely, the combination of the arc tube 2 and the external electrode 6 is called a “barrier discharge lamp”, the barrier discharge lamp 1 corresponds to the ultraviolet irradiation unit 10 .

The lighting device 60 is arranged on the back side of the housing member 50 and electrically connected to the internal electrode 3 and the external electrode 6 provided inside the arc tube 2 of the ultraviolet irradiation unit 10 . By arranging the lighting device 60 on the back side of the housing member 50 in this way, the wiring length between the lighting device 60 and the ultraviolet irradiation unit 10 can be shortened. Note that the arrangement of the lighting device 60 is not limited to the style shown in FIG.

Further, the lighting device 60 includes an inverter capable of outputting high voltage and high frequency, and is configured to be able to supply electric power from an AC power supply (not shown) to the ultraviolet irradiation unit 1 . The lighting device 60 can apply a sine wave with a frequency of 120 [ kHz ] , for example, and light the arc tube 2 of the ultraviolet irradiation unit 1 with a lamp power of about 1 [ kW ] .

As described above, the barrier discharge lamp 1 according to the embodiment includes the cylindrical arc tube 2, the internal electrode 3, and the reflective film 5. The barrier discharge lamp 1 performs barrier discharge between an internal electrode 3 provided inside the arc tube 2 and an external electrode 6 provided near the arc tube 2 . The arc tube 2 is filled with gas and transmits ultraviolet light. The internal electrode 3 is arranged inside the arc tube 2 and a spiral conductor extends in the length direction of the arc tube 2 . The reflective film 5 is provided on the inner surface 2 a of the arc tube 2 and reflects ultraviolet light to the inside of the arc tube 2 . The light-emitting tube 2 has a plurality of recesses 4 for restricting movement of the internal electrodes 3 in portions different from the reflective film 5 . The diameter d [mm] of the recess 4 and the wire diameter D [mm] of the internal electrode 3 have a relationship of d≦10D. As a result, problems due to abrasion or peeling of the reflective film can be suppressed.

Further, the diameter d [mm] according to the embodiment and the pitch P [mm] of the internal electrodes 3 in the axial direction of the arc tube 2 have a relationship of d≦P. As a result, problems associated with scattering of ultraviolet light in the concave portion 4 can be reduced.

Further, the external electrode 6 according to the embodiment is provided on the outer surface 2b side of the arc tube 2 corresponding to the inner surface 2a on which the reflective film 5 is provided. The external electrode 6 is a heat dissipation block made of aluminum or stainless steel. Thereby, heat dissipation can be ensured without separately providing a heat dissipation member.

While embodiments of the invention have been described, the embodiments are provided by way of example and are not intended to limit the scope of the invention. Embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. The embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and its equivalents.

REFERENCE SIGNS LIST 1 barrier discharge lamp 2 arc tube 3 internal electrode 4 concave portion 5 reflective film 6 external electrode 10 ultraviolet irradiation unit 50 housing member 60 lighting device 100 ultraviolet irradiation device

Claims (7)

a cylindrical arc tube filled with gas and transparent to ultraviolet light;
an internal electrode disposed inside the arc tube and having a helical conductor extending in the axial direction of the arc tube;
a reflective film provided on the inner surface of the arc tube for reflecting the ultraviolet light to the inside of the arc tube;
and performing barrier discharge between the internal electrode provided inside the arc tube and the external electrode provided on the outer surface side of the arc tube,
the arc tube has a plurality of concave portions for restricting the movement of the internal electrode in a portion different from the reflective film;
The barrier discharge lamp, wherein a diameter d [mm] of the recess and a wire diameter D [mm] of the internal electrode have a relationship of d≦10D. 2. The barrier discharge lamp according to claim 1, wherein an inner surface of said recess projects inwardly of said arc tube and contacts said internal electrode. 3. The barrier discharge lamp according to claim 1, wherein said diameter d [mm] and said pitch P [mm] of said internal electrodes in said tube axis direction have a relationship of d≦P. 4. The method according to any one of claims 1 to 3, wherein the external electrode is a heat dissipation block made of aluminum or stainless steel provided on the outer surface side of the arc tube corresponding to the inner surface on which the reflective film is provided. A barrier discharge lamp as described. a barrier discharge lamp according to any one of claims 1 to 4;
the external electrode;
An ultraviolet irradiation unit. An ultraviolet irradiation unit according to claim 5;
a housing portion that houses the ultraviolet irradiation unit;
An ultraviolet irradiation device. a cylindrical arc tube filled with gas and transparent to ultraviolet light;
an internal electrode disposed inside the arc tube and having a helical conductor extending in the axial direction of the arc tube;
a reflective film provided on the inner surface of the arc tube for reflecting the ultraviolet light to the inside of the arc tube;
an external electrode provided on the outer surface side of the arc tube corresponding to the inner surface provided with the reflective film;
and
the arc tube has a plurality of concave portions for restricting the movement of the internal electrode in a portion different from the reflective film;
The barrier discharge lamp, wherein a diameter d [mm] of the recess and a wire diameter D [mm] of the internal electrode have a relationship of d≦10D.

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