TWI790362B - Ultraviolet irradiation unit, ultraviolet irradiation device, and shielding discharge lamp - Google Patents

Abstract

The present invention provides an ultraviolet irradiation unit, an ultraviolet irradiation device, and a shielded discharge lamp capable of obtaining irradiation characteristics corresponding to requirements. The ultraviolet irradiation unit includes a shield discharge lamp and external electrodes. The shield discharge lamp has a luminous tube and internal electrodes. The luminous tube is sealed with gas, and allows ultraviolet light to pass through. The luminous tube is cylindrical. The internal electrodes are arranged inside the luminous tube and extend in the direction of the tube axis of the luminous tube. The external electrode is arranged on the outer surface side of the luminous tube in such a way as to face the internal electrode, and in the circumferential direction of the luminous tube, it exceeds 180[°] and is less than 300[°], or exceeds 300[°] and 330[°] ] The range below covers the LED.

Description

Ultraviolet irradiation unit, ultraviolet irradiation device, and shielding discharge lamp

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

Conventionally, there are known ultraviolet irradiation devices used for the purpose of cleaning or modifying substrates. In the ultraviolet ray irradiation device, there is a shielding discharge lamp including a shielding discharge lamp that is connected to an alternating current by connecting an internal electrode disposed inside a luminous tube as a dielectric and an external electrode disposed outside the luminous tube. The dielectric barrier discharge generated on the power source emits ultraviolet light having a specific wavelength corresponding to the gas contained in the arc tube.

[Prior art literature] [Patent Document] [Patent Document 1] Japanese Patent Laid-Open No. 2013-211164

In the shield discharge lamp as described above, for example, irradiation characteristics suitable for the application, such as illuminance and integrated light quantity, are required.

The problem to be solved by the present invention is to provide an ultraviolet irradiation unit, an ultraviolet irradiation device, and a shield discharge lamp capable of obtaining irradiation characteristics corresponding to requirements.

According to one embodiment, the ultraviolet irradiation unit includes a shield discharge lamp and an external electrode. The shield discharge lamp has a luminous tube and internal electrodes. The luminous tube is sealed with gas, and allows ultraviolet light to pass through. The luminous tube is cylindrical. The internal electrodes are arranged inside the luminous tube and extend in the direction of the tube axis of the luminous tube. The external electrode is provided on the outer surface side of the arc tube so as to face the internal electrode, and covers the arc tube over 180[°] and not more than 300[°] in the circumferential direction of the arc tube.

[Effect of the invention] According to the present invention, irradiation characteristics corresponding to requirements can be obtained.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail together with the accompanying drawings.

The ultraviolet irradiation unit 1 and the ultraviolet irradiation unit 1A of the embodiment described below include a shield discharge lamp and an external electrode 6 . The shield discharge lamp has a luminous tube 2 and an internal electrode 3 . The luminous tube 2 is sealed with gas, and allows ultraviolet light to pass through. The luminous tube 2 is cylindrical. The internal electrode 3 is disposed inside the arc tube 2 and extends in the direction of the tube axis of the arc tube 2 . The external electrode 6 is provided on the outer surface 2b side of the arc tube 2 so as to face the internal electrode 3, and covers the arc tube 2 in a range of more than 180[°] and not more than 300[°] in the circumferential direction of the arc tube 2.

In addition, the ultraviolet irradiation unit 1 and the ultraviolet irradiation unit 1A of the embodiment described below include a shield discharge lamp and an external electrode 6 . The shield discharge lamp has a luminous tube 2 and an internal electrode 3 . The luminous tube 2 is sealed with gas, and allows ultraviolet light to pass through. The luminous tube 2 is cylindrical. The internal electrode 3 is disposed inside the arc tube 2 and extends in the direction of the tube axis of the arc tube 2 . The external electrode 6 is provided on the outer surface 2 b side of the arc tube 2 so as to face the internal electrode 3 , and covers the arc tube 2 in a range of more than 300 [°] and not more than 330 [°] in the circumferential direction of the arc tube 2 .

In addition, the external electrode 6 of the embodiment described below has a first member 7 covering the arc tube 2 in the circumferential direction, and a second member 8 disposed so as to face each other with the arc tube 2 interposed therebetween.

In addition, the external electrode 6 of the embodiment described below has a first member 7 covering the arc tube 2 in the circumferential direction, and a pair of second members 8 arranged to face each other with the arc tube 2 interposed therebetween. 8.

In addition, the ultraviolet irradiation unit 1 and the ultraviolet irradiation unit 1A of the embodiment described below include the reflective film 4 . Reflective film 4 is provided on inner surface 2 a of arc tube 2 facing external electrode 6 , and reflects ultraviolet light toward the inside of arc tube 2 . The angle θ4 in the circumferential direction of the reflective film 4 is equal to or greater than the angle θ6 in the circumferential direction of the arc tube 2 covered by the external electrode 6 .

In addition, the ultraviolet irradiation device 100 of the embodiment described below includes the ultraviolet irradiation unit 1 , the ultraviolet irradiation unit 1A, and the housing portion 50 that accommodates the ultraviolet irradiation unit 1 and the ultraviolet irradiation unit 1A.

In addition, shield discharge lamp 1 and shield discharge lamp 1A according to the embodiment described below include arc tube 2 , internal electrode 3 , and external electrode 6 . The luminous tube 2 is sealed with gas, and allows ultraviolet light to pass through. The luminous tube 2 is cylindrical. The internal electrode 3 is disposed inside the arc tube 2 and extends in the direction of the tube axis of the arc tube 2 . The external electrode 6 is provided on the outer surface 2b side of the arc tube 2 so as to face the internal electrode 3, and covers the arc tube 2 in a range of more than 180[°] and not more than 300[°] in the circumferential direction of the arc tube 2.

In addition, shield discharge lamp 1 and shield discharge lamp 1A according to the embodiment described below include arc tube 2 , internal electrode 3 , and external electrode 6 . The luminous tube 2 is sealed with gas, and allows ultraviolet light to pass through. The luminous tube 2 is cylindrical. The internal electrode 3 is disposed inside the arc tube 2 and extends in the direction of the tube axis of the arc tube 2 . The external electrode 6 is provided on the outer surface 2 b side of the arc tube 2 so as to face the internal electrode 3 , and covers the arc tube 2 in a range of more than 300 [°] and not more than 330 [°] in the circumferential direction of the arc tube 2 .

Hereinafter, embodiments of the present invention will be described based on the drawings. In addition, embodiment shown below does not limit the technology disclosed by this invention.

FIG. 1 is a plan view showing an ultraviolet irradiation unit according to an embodiment, and FIG. 2 is an AA' cross-sectional view of FIG. 1 . As shown in FIGS. 1 and 2 , an ultraviolet irradiation unit 1 according to the embodiment has a light emitting tube 2 and an external electrode 6 as a shield discharge lamp. The luminous tube 2 has an internal electrode 3 , a reflective film 4 , a wire 5 , and a lamp socket 9 . Note that, in the following description, the shield discharge lamp will be described only as the arc tube 2 . In addition, in the present embodiment, the ultraviolet irradiation unit 1 is provided with an external electrode 6 on the outside of the arc tube 2 as a shield discharge lamp, but the ultraviolet irradiation unit 1 may be used, more specifically, as a A form in which the outer electrode 6 is combined with the outside of the arc tube 2 of the shield discharge lamp is called a "shield discharge lamp".

1 and 2 illustrate a three-dimensional orthogonal coordinate system including the Z-axis with the irradiation surface side in the positive direction and the rear side in the negative direction for easy understanding of the description. The orthogonal coordinate system is also shown in other drawings used in the description below.

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 ray transmittance at a wavelength of 200 [nm] or less is exemplified. In addition, both ends in the tube axial direction (X-axis direction) of the arc tube 2 are held by a sealing member having a rod structure, and are hermetically sealed. From the viewpoint of suppressing stress cracks accompanying ultraviolet irradiation, for example, the outer diameter D of the arc tube 2 can be set to 30 [mm] or more. In addition, for example, the length LY in the tube axis direction of the arc tube 2 can be set to 750 [mm].

In addition, gas is sealed inside the arc tube 2 . The gas is, for example, xenon gas of 80 [kPa] to 200 [kPa]. Furthermore, the gas may contain, for example, one of krypton, xenon, argon, neon, etc., or a combination of a plurality of gases. Furthermore, the gas may contain, for example, a halogen gas as needed. The luminous tube 2 can emit ultraviolet light (excimer light) having a specific peak wavelength corresponding to the type of enclosed gas.

The internal electrodes 3 are arranged inside the arc tube 2 . The helical conductor of the internal electrode 3 extends in the direction of the tube axis of the arc tube 2 . Internal electrode 3 is formed of, for example, a material containing tungsten. Specifically, 50 [%] or more of the total components of the internal electrodes 3 is tungsten. In particular, when doped tungsten obtained by adding potassium or the like to tungsten is used as the internal electrode 3, higher dimensional stability can be maintained even at high temperatures. For example, the pitch P of the internal electrodes 3 in the tube axis direction can be set to not less than 10 [mm] and not more than 30 [mm].

The reflective film 4 is provided on the inner surface 2 a of the arc tube 2 to reflect ultraviolet light toward the inside of the arc tube 2 . As a material of the reflective film 4, silicon dioxide is exemplified, for example. In addition, the reflective film 4 is not limited to silicon dioxide, and may include, for example, a material containing ultraviolet scattering particles such as aluminum oxide. From the viewpoint of maintaining good reflectance, the reflective film 4 is formed to have a thickness of, for example, 100 [μm] or more and 300 [μm] or less.

In addition, the angle θ4 of the reflective film 4 in the circumferential direction of the arc tube 2 (hereinafter referred to as the angle θ4 of the reflective film 4 ) becomes the angle θ6 of the circumferential direction of the arc tube 2 covered by the external electrode 6 (hereinafter referred to as the angle θ4 of the external electrode 6 ). The angle θ6 of 6) is configured in the above manner. Thereby, the object to be irradiated can be efficiently irradiated with ultraviolet light generated in the arc tube 2 . However, as a modified example of the shield discharge lamp of the embodiment, a form without the reflective film 4 is also allowed.

The external electrode 6 is provided on the back side of the arc tube 2 facing the internal electrode 3 , that is, on the outer surface 2 b side of the arc tube 2 corresponding to the inner surface 2 a of the arc tube 2 on which the reflective film 4 is provided. The external electrode 6 also functions as a heat sink for dissipating heat from the heated arc tube 2, and may be made of aluminum or stainless steel, for example.

The external electrode 6 has a first member 7 and a pair of second members 8 . The first member 7 covers the arc tube 2 at an angle θ7 of 180[°] or less in the circumferential direction of the arc tube 2 . The first member 7 and the arc tube 2 may be in contact with each other or separated, but if the first member 7 is brought into contact with the arc tube 2, heat dissipation can be improved. In addition, a flow path 10 through which liquid or gas refrigerant flows is provided inside the first member 7 . By allowing the refrigerant to flow through the flow path 10, the heat dissipation performance is further improved. In addition, although the example which has two flow paths 10 is shown in FIG. 2, the number of flow paths 10 may be one, or may be three or more.

A pair of 2nd member 8 has the 2nd member piece 8a and the 2nd member piece 8b arrange|positioned along the X-axis direction so that it may oppose each other with the arc tube 2 interposed. The second member piece 8 a and the second member piece 8 b are respectively fixed to the first member 7 by the fixing member 11 and the fixing member 12 , and the first member 7 and the second member 8 cooperate to function as the external electrode 6 . The fixing member 11 and the fixing member 12 are screws, for example. Thus, since the external electrode 6 has the 2nd member 8, compared with the case where the 1st member 7 is used solely as the external electrode 6, the degree of freedom of the design and performance of the ultraviolet irradiation unit 1 increases. In addition, the first member 7 and the second member 8 may be electrically connected by contact, for example, may be electrically connected via a conductor not shown in the figure such as a wire.

Here, the angle θ6 of the external electrode 6 can be set according to the required integrated light quantity or illuminance. For example, in order to increase the integrated light quantity, it may be 180[°]<θ6≦300[°]. On the other hand, in order to increase the illuminance, it may be 300[°]<θ6≦330[°].

The wire 5 is electrically connected to the internal electrode 3 . In addition, the lead wire 5 is connected to an unillustrated lighting device connected to an AC power source, and a predetermined voltage can be applied between the electrodes of the internal electrode 3 and the external electrode 6 provided inside the arc tube 2 to emit light. In addition, the lead wire 5 is not limited to the structure provided at both ends of the arc tube 2 as shown in FIG.

The socket 9 is disposed so as to cover one end side of the lead wire 5 , and supports both ends of the arc tube 2 in the tube axis direction. In addition, the base 9 is not limited to the structure in which the external electrode 6 is provided in contact with the base 9 as shown in FIG. 1 , and the external electrode 6 and the base 9 may be provided with a gap, for example.

[modified example] The external electrode 6 shown in FIGS. 1 and 2 includes a first member 7 and a pair of second members 8 , but is not limited thereto. 3 is a cross-sectional view showing an ultraviolet irradiation unit according to a modified example of the embodiment. The external electrode 6 of the ultraviolet irradiation unit 1A shown in FIG. 3 includes a first member 7 , a pair of second members 8 , and a pair of third members 13 .

A pair of 3rd member 13 has the 3rd member piece 13a and the 3rd member piece 13b which are arrange|positioned along the X-axis direction so that they may oppose each other with the arc tube 2 in between. The 3rd component piece 13a, the 3rd component piece 13b are respectively fixed on the 2nd component piece 8a, the 2nd component piece 8b and the 1st component 7 by the fixing member 21, the fixing member 22, the 1st component 7, the 2nd component The member 8 and the third member 13 cooperate to function as the external electrode 6 . The fixing member 21 and the fixing member 22 are screws, for example. Thus, by further having the pair of third members 13 in the external electrode 6 , the angle θ6 of the external electrode 6 can be increased compared to the case where the first member 7 and the pair of second members 8 are used as the external electrode 6 . Furthermore, in the example shown in FIG. 3 , the pair of second members 8 and the pair of third members 13 are respectively penetrated by the immobilization member 21 and the immobilization member 22 to be integrated, but it is not limited thereto. For example, the first member 7 and the pair of second members 8 , and the pair of second members 8 and the pair of third members 13 may be respectively fixed for integration.

As described above, the external electrode 6 can change the illuminance and the integrated light quantity according to the angle θ6 in the circumferential direction of the arc tube 2 covered by the external electrode 6 . FIG. 4 is a graph showing the relationship between the angle of the external electrodes and the discharge area per 1 [cm] in the longitudinal direction. 5 is a graph showing the relationship between the discharge area per 1 [cm] in the longitudinal direction of the external electrodes, the illuminance, and the integrated light quantity. In addition, "the discharge area per 1 [cm] in the longitudinal direction of the external electrode" refers to multiplying the length of the arc calculated from the angle of the external electrode 6 by the length in the longitudinal direction of the arc tube 2. Specifically, The value obtained by multiplying the words by 1 [cm]. FIG. 5 is a diagram illustrating a case where xenon gas is sealed in the arc tube 2 . In addition, the cumulative light quantity is the cumulative light quantity which exemplifies the case where the object to be irradiated is conveyed in the tube axis direction at a speed of 10 [mm/s].

As shown in FIG. 5 , the larger the angle θ6 of the external electrode 6 , that is, the larger the discharge area per 1 [cm] in the longitudinal direction of the external electrode 6 , the larger the peak value of the illuminance. Therefore, in order to increase the illuminance, it can be 300[°]<θ6≦330[°]. On the other hand, the larger the angle θ6 is, the smaller the emission area is, so the integrated light quantity increases until it reaches a maximum value, and then decreases. Therefore, in order to increase the integrated light quantity, it can be 180[°]<θ6≦300[°].

Here, the angles of the external electrodes 6 shown in FIG. 4 , that is, the angles θ6=180[°], 238[°], and 327[°] respectively correspond to the case where only the first member 7 is used as the external electrode 6, When the first member 7 and the pair of second members 8 are used as the external electrodes 6 , and when the first member 7 , the pair of second members 8 , and the pair of third members 13 are used as the external electrodes 6 . However, the angle θ6 of the external electrode 6 is not limited to the illustrated angle, and for example, the shapes of the pair of second members 8 and the pair of third members 13 can be changed to a desired angle θ6, of course.

[Ultraviolet irradiation device] 6A and 6B are diagrams showing an ultraviolet irradiation device having an ultraviolet irradiation unit according to an embodiment. FIG. 6A is a view viewed from the tube axis direction (Y-axis direction), and FIG. 6B is a view viewed from the X-axis direction. As shown in FIG. 6A and FIG. 6B , the ultraviolet irradiation device 100 according to the embodiment has a housing portion 50 and a lighting device 60 . One or a plurality of ultraviolet irradiation units 1 are accommodated in the accommodation portion 50 . In addition, instead of the ultraviolet irradiation unit 1, the ultraviolet irradiation unit 1A may be accommodated in the accommodating part 50.

The lighting device 60 is arranged on the back side of the housing portion 50 and is electrically connected to the internal electrode 3 and the external electrode 6 provided inside the arc tube 2 of the ultraviolet irradiation unit 1 . By arranging the lighting device 60 on the back side of the housing portion 50 as described above, the wiring length between the lighting device 60 and the shield discharge lamp 1 can be shortened. Furthermore, the arrangement of the lighting device 60 is not limited to those shown in FIGS. 6A and 6B , and the lighting device 60 may be provided outside the ultraviolet irradiation device 100 , for example.

In addition, the lighting device 60 includes an inverter capable of outputting high voltage and high frequency, and is configured to supply power from an unshown AC power source to the arc tube 2 and the external electrode 6 of the ultraviolet irradiation unit 1 . The lighting device 60 can apply, for example, a sine wave with a frequency of 120 [kHz] to light the arc tube 2 of the ultraviolet irradiation unit 1 with a lamp power of about 1 [kW].

As described above, the ultraviolet irradiation unit 1 and the ultraviolet irradiation unit 1A of the embodiment include the shield discharge lamp and the external electrode 6 . The shield discharge lamp has a luminous tube 2 and an internal electrode 3 . The luminous tube 2 is sealed with gas, and allows ultraviolet light to pass through. The luminous tube 2 is cylindrical. The internal electrode 3 is disposed inside the arc tube 2 and extends in the direction of the tube axis of the arc tube 2 . The external electrode 6 is provided on the outer surface 2b side of the arc tube 2 so as to face the internal electrode 3, and covers the arc tube 2 in a range of more than 180[°] and not more than 300[°] in the circumferential direction of the arc tube 2. Thus, according to the ultraviolet irradiation unit 1 and the ultraviolet irradiation unit 1A of the embodiment, the integrated light quantity can be increased.

In addition, the ultraviolet irradiation unit 1 and the ultraviolet irradiation unit 1A of the embodiment include a shield discharge lamp and an external electrode 6 . The shield discharge lamp has a luminous tube 2 and an internal electrode 3 . The luminous tube 2 is sealed with gas, and allows ultraviolet light to pass through. The luminous tube 2 is cylindrical. The internal electrode 3 is disposed inside the arc tube 2 and extends in the direction of the tube axis of the arc tube 2 . The external electrode 6 is provided on the outer surface 2 b side of the arc tube 2 so as to face the internal electrode 3 , and covers the arc tube 2 in a range of more than 300 [°] and not more than 330 [°] in the circumferential direction of the arc tube 2 . Thus, according to the ultraviolet irradiation unit 1 and the ultraviolet irradiation unit 1A of the embodiment, the illuminance can be increased.

In addition, the external electrode 6 of the embodiment has a first member 7 and a pair of second members 8 . The first member 7 covers the arc tube 2 in the circumferential direction. The second members 8 are disposed so as to face each other across the arc tube 2 . This increases the degree of freedom in design and performance.

In addition, the ultraviolet irradiation unit 1 and the arc tube 2 of the ultraviolet irradiation unit 1A according to the embodiment include a reflective film 4 . Reflective film 4 is provided on inner surface 2 a of arc tube 2 facing external electrode 6 , and reflects ultraviolet light toward the inside of arc tube 2 . The angle θ4 in the circumferential direction of the reflective film 4 is equal to or greater than the angle θ6 in the circumferential direction of the arc tube 2 covered by the external electrode 6 . Thereby, ultraviolet light can be efficiently irradiated to an irradiation target.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in other various forms, and various omissions, substitutions, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and their equivalents as well as being included in the scope or spirit of the invention.

1. 1A: UV irradiation unit (shielded discharge lamp) 2: LED 2a: inner surface 2b: Outer surface 3: Internal electrodes 4: reflective film 5: Wire 6: External electrodes 7: 1st component 8: 2nd component 8a, 8b: the second member sheet 9: Lamp port 10: flow path 11, 12: Fixed components

13: 3rd component

13a, 13b: the third member piece

21, 22: Fixed components

50: Containment

60: Lighting device

100: Ultraviolet irradiation device

D: outer diameter

LY: Length

P: Pitch

X, Y, Z: axes

XI, θ4 , θ6, θ7: angle

FIG. 1 is a plan view showing an ultraviolet irradiation unit according to an embodiment. FIG. 2 is an AA' sectional view of FIG. 1 . 3 is a cross-sectional view showing an ultraviolet irradiation unit according to a modified example of the embodiment. FIG. 4 is a graph showing the relationship between the angle of the external electrodes and the discharge area per 1 [cm] in the longitudinal direction. 5 is a graph showing the relationship between the discharge area per 1 [cm] in the longitudinal direction of the external electrodes, the illuminance, and the integrated light quantity. 6A and 6B are diagrams showing an ultraviolet irradiation device having an ultraviolet irradiation unit according to an embodiment.

1: Ultraviolet irradiation unit (shielded discharge lamp)

2: LED

2a: inner surface

2b: Outer surface

3: Internal electrodes

4: reflective film

7: 1st component

8: 2nd component

8a, 8b: the second member sheet

10: flow path

11, 12: Fixed components

D: outer diameter

X, Y, Z: axes

θ4, θ6, θ7: angle

Claims (7)

An ultraviolet irradiation unit, comprising: a shielded discharge lamp having a cylindrical luminous tube, which is sealed with gas to transmit ultraviolet light; and an internal electrode arranged inside the luminous tube and on the tube axis of the luminous tube extending in the direction; and the external electrode is provided on the outer surface side of the luminous tube in such a manner as to face the internal electrode, in the circumferential direction of the luminous tube at an angle of more than 180 [°] and 330 [°] or less. The range covers the arc tube, wherein the external electrode has: a first member covering the arc tube in the circumferential direction; and a pair of second members arranged to face each other with the arc tube interposed therebetween. . An ultraviolet irradiation unit, characterized in that it includes: a shielding discharge lamp, having a cylindrical luminous tube, which is sealed with gas to transmit ultraviolet light; and an internal electrode, arranged inside the luminous tube and placed in the Extending in the direction of the tube axis; and the external electrode is provided on the outer surface side of the light emitting tube in a manner facing the internal electrode, and exceeds 300[°] and 330[° in the circumferential direction of the light emitting tube ] The range below covers the LED. The ultraviolet irradiation unit as described in claim 2 of the patent application, wherein the external electrode has: a first member covering the arc tube in the circumferential direction; and a second member for interposing the arc tube Configured in the opposite way. The ultraviolet irradiating unit as described in claim 2 of the scope of the patent application further includes a reflective film, which is provided on the inner surface of the light-emitting tube in a manner facing the external electrode, and the reflective film is arranged in the circumferential direction The arc length of the external electrode is greater than the arc length of the external electrode in the circumferential direction, and the reflective film that makes the ultraviolet light reflect toward the inside of the light-emitting tube, and the angle of the circumferential direction of the reflective film is greater than The angle of the circumferential direction of the light emitting tube covered by the external electrode. An ultraviolet irradiation device, comprising: the ultraviolet irradiation unit according to any one of items 1 to 4 of the scope of the patent application; and a housing part for accommodating the ultraviolet irradiation unit. A shielded discharge lamp, comprising: a cylindrical luminous tube, sealed with gas, and allowing ultraviolet light to pass through; an internal electrode, arranged inside the luminous tube, and extending in the direction of the tube axis of the luminous tube; and The external electrode is provided on the outer surface side of the arc tube so as to face the internal electrode, and covers the arc tube in a range of more than 180[°] to 330[°] The arc tube, wherein the external electrode has: a first member covering the arc tube in the circumferential direction; and a pair of second members arranged to face each other with the arc tube interposed therebetween. A shielded discharge lamp comprising: The cylindrical luminous tube is sealed with gas and allows ultraviolet light to pass through; the internal electrode is arranged inside the luminous tube and extends in the direction of the tube axis of the luminous tube; and the external electrode is connected to the The internal electrodes are disposed on the outer surface side of the arc tube so as to face each other, and cover the arc tube in a range of more than 300[°] and not more than 330[°] in the circumferential direction of the arc tube.

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