TWI641020B - Discharging lamp - Google Patents

Abstract

The present invention provides a discharge lamp which can increase the amount of light irradiated from the end portion in the longitudinal direction of the discharge lamp. The discharge lamp includes: a discharge tube 2; a pair of electrodes 31 and 32, which are disposed along the longitudinal direction of the discharge tube 2; and a reflection film 4 having an opening 5 on the discharge tube 2 along the longitudinal direction of the discharge tube 2. In the end portion and the end light-emitting region, the pair of electrodes 31 and 32 are disposed at at least one end portion of the discharge tube 2 so as to sandwich an area outside the end portion in the longitudinal direction of the reflection film 4. The light-transmitting region Rx formed in the workpiece direction at least outside the end portion in the longitudinal direction of the reflective film 4 and at least a portion of the region where the end light-emitting region in the longitudinal direction of the discharge tube 2 is located is wider than the discharge tube A light-transmitting region in the workpiece direction at the center portion in the longitudinal direction of 2.

Description

Discharge lamp

The present invention relates to a discharge lamp such as an ultraviolet lamp called an excimer lamp.

As an excimer lamp, as disclosed in Patent Document 1, for example, a straight tubular discharge tube having a rectangular cross section and a pair of electrodes provided on an outer surface of the discharge tube are provided to generate a pair of electrodes. The excimer is discharged and irradiated with, for example, vacuum ultraviolet rays having a wavelength of around 170 nm.

Further, on the inner surface of the discharge tube, for example, an ultraviolet reflecting film containing cerium oxide particles is formed. By forming the ultraviolet ray reflection film in this manner, the ultraviolet ray generated inside the discharge tube is scattered and reflected by the reflection film, whereby the amount of light emitted from the light emitting portion to the outside can be increased.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-55971

However, in the end portion in the longitudinal direction of the ultraviolet ray reflection film, the amount of light is reduced due to scattering reflection, so that the amount of light emitted from the end portion in the longitudinal direction of the light emitting portion also decreases. Therefore, as shown in FIG. 8, there is a problem that the light amount distribution (light amount uniformity) in the longitudinal direction of the illuminated surface is deteriorated. In other words, in the excimer lamp, there is a problem that the amount of light in the end portion in the longitudinal direction is smaller than that in the central portion.

Accordingly, the present invention has been made to solve the above problems, and provides a discharge lamp which can increase the amount of light irradiated from the end portion in the longitudinal direction of the discharge lamp.

That is, the discharge lamp of the present invention includes: a discharge tube; a pair of electrodes disposed in the discharge tube along a longitudinal direction of the discharge tube; and a reflective film along the longitudinal direction of the discharge tube The discharge tube is provided with an opening, and the end light-emitting region is disposed at least one end portion of the discharge tube so as to sandwich an area outside the end portion of the reflection film in the longitudinal direction. a pair of electrodes formed thereby at a portion outside the end portion in the longitudinal direction of the reflective film, and at least a portion of the region in which the end portion of the discharge tube is located in the longitudinal direction The light-transmitting region in the direction is wider than the light-transmitting region in the direction of the workpiece in the central portion in the longitudinal direction of the discharge tube.

According to the discharge lamp, the amount of light irradiated from the end portion in the longitudinal direction of the discharge lamp can be increased.

It is preferable that the pair of electrodes are disposed on an outer surface of the discharge tube in a direction along a longitudinal direction including the light transmitting region.

According to this, discharge can be generated in the light-transmitting region, so that the amount of light irradiated from the end portion in the longitudinal direction of the discharge lamp can be further increased.

It is preferable that one of the pair of electrodes is a mesh electrode provided on the opening side, and the other is a plate electrode.

According to this, the light generated by the discharge in the light-transmitting region can be reflected by the plate-shaped electrode in the direction of the opening portion, so that the amount of light irradiated from the end portion in the longitudinal direction of the discharge lamp can be further increased.

It is preferable that a part of the pair of electrodes disposed so as to sandwich a region outside the end portion in the longitudinal direction of the reflection film is used as a window for an optical monitor.

According to this, it is possible to control the amount of light to be irradiated from the discharge lamp, and it is also unnecessary to newly provide a dedicated space for forming the window for the optical monitor, and thus the design becomes easy.

According to the discharge lamp configured as described above, the amount of light irradiated from the end portion in the longitudinal direction of the discharge lamp can be increased.

2‧‧‧Discharge tube

2a‧‧‧One end of the long side

2b‧‧‧The other end of the long side

2c‧‧‧The central part of the long side

2W‧‧‧monitor window

4‧‧‧Reflective film

4a, 4b‧‧‧ end

4m, 4n‧‧‧ the end of the long side of the reflective film

5‧‧‧ openings

6‧‧‧Shade film

6m, 6n‧‧‧ long-side end of the light-shielding film

21‧‧‧Upper wall

22‧‧‧ Lower wall

23‧‧‧ Front wall

24‧‧‧Back wall

25‧‧‧ left wall

26‧‧‧ right wall

31, 32‧‧‧ a pair of electrodes

31a, 31b, 32a, 32b‧‧‧ the end of the long side of the external electrode

100‧‧‧discharge lamp

251‧‧‧The inner surface of the left side wall

261‧‧‧The inner surface of the right side wall

HS‧‧‧ face

Rx‧‧‧Light transmission area

Fig. 1 is a perspective view showing a discharge lamp of the embodiment.

Fig. 2 is a bottom view showing the discharge lamp of the embodiment.

Fig. 3 is a cross-sectional view taken along line A-A' of the discharge lamp of the embodiment.

Fig. 4 is an enlarged cross-sectional view taken along line BB' of the discharge lamp of the embodiment.

Fig. 5 is a bottom view showing a discharge lamp according to another embodiment.

Fig. 6 is an enlarged cross-sectional view taken along line BB' of the discharge lamp of another embodiment.

FIG. 7 is a view schematically showing a light amount distribution in the longitudinal direction of the discharge lamp of the embodiment.

FIG. 8 is a view schematically showing a light amount distribution in the longitudinal direction of a conventional discharge lamp.

Hereinafter, an embodiment of a discharge lamp of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 to 4, the discharge lamp 100 of the present embodiment is a dielectric barrier discharge lamp including a straight tubular discharge tube 2 and a longitudinal direction on the outer surface of the discharge tube 2. A pair of external electrodes 31 and external electrodes 32 which are disposed to face each other. In the following description, the longitudinal direction of the discharge tube 2 is set to the left-right direction, and the two directions orthogonal to the longitudinal direction of the discharge tube 2 are referred to as the front-rear direction and the vertical direction (hereinafter, also Called the short side direction).

The discharge tube 2 is made of synthetic quartz glass and has a pair of flat upper wall portions 21 and lower wall portions 22 that face up and down and has an elongated shape. In particular, as shown in FIG. 3, the discharge tube 2 of the present embodiment includes an upper wall portion 21 and a lower wall portion 22, and a curved front wall portion 23 that is connected to the front end portions of the upper wall portion 21 and the lower wall portion 22, and The curved rear wall portion 24 to which the rear end portions of the upper wall portion 21 and the lower wall portion 22 are connected is substantially rail-shaped in cross section. Further, both end portions of the discharge tube 2 in the longitudinal direction are closed by the left wall portion 25 and the right wall portion 26. Further, the left wall portion 25 and the right wall portion 26 are formed by welding a synthetic quartz block on a synthetic quartz glass tube constituting the discharge tube 2.

Further, a dielectric barrier discharge gas is filled in the discharge space formed inside the discharge tube 2. Further, as the dielectric barrier discharge gas, a rare gas such as xenon (Xe), argon (Ar) or helium (Kr), or a halogen gas such as fluorine (F ₂ ) or chlorine (Cl ₂ ) may be used. The discharge lamp 2 emits excimer light of different wavelengths (172 nm, 222 nm, 308 nm, etc.) depending on the type of gas. For example, in order to decompose an organic compound, helium (Xe) is used as a gas for discharge to form a dielectric barrier discharge lamp that emits excimer light having a center wavelength of 172 nm.

The pair of external electrodes 31 and the external electrodes 32 have a film shape having a length substantially equal to the discharge space of the discharge tube 2, and are provided at positions that sandwich the discharge space of the discharge tube 2 from the vertical direction, that is, the upper wall portion 21 and Lower wall portion 22. The external electrode 31 and the external electrode 32 are made of a conductive material such as aluminum, aluminum alloy, or stainless steel, and are formed on the side surface of the discharge tube 2 by plating, sputtering, vapor deposition, or sputtering, for example. . The external electrode 31 provided in the upper wall portion 21 is a plate-shaped electrode (hereinafter referred to as a plate electrode). Further, the external electrode 32 provided on the lower wall portion 22 is a mesh-shaped electrode (hereinafter referred to as a mesh electrode). Further, excimer light is emitted from the external electrode 32 provided on the lower wall portion 22.

On the inner surface of the discharge tube 2 of the present embodiment, a reflection film 4 that reflects excimer light generated inside the discharge tube 2 is formed.

The reflection film 4 is provided on the inner circumferential surface (hereinafter simply referred to as an inner circumferential surface) parallel to the longitudinal direction of the discharge tube 2 in the longitudinal direction. Specifically, it is provided across the upper wall portion 21, the front wall portion 23, and the rear wall portion 24 of the discharge tube 2 (see FIG. 3). Further, a part of the reflective film 4 may be formed to extend across the lower wall portion 22. Further, the reflective film 4 is provided with an opening in the longitudinal direction. Specifically, there is an inner circumferential surface of the inner circumferential surface The opening portions 5 between the both end portions 4a and 4b of the reflection film 4 serve as light-transmitting regions in the workpiece direction.

In the present embodiment, the positions of the both end portions 4a and 4b of the reflective film 4 are set so that the opening portion 5 is provided in all or part of the lower wall portion 22 of the discharge tube 2.

In the longitudinal direction end portion 31a, the longitudinal end portion 31b, the longitudinal end portion 32a, and the longitudinal end portion 32b of the pair of external electrodes 31 and the external electrode 32 of the present embodiment, the discharge tube is sandwiched In the longitudinal direction end portion 4m and the longitudinal end portion 4n of the reflection film 4, the end portion 2a in the longitudinal direction of the discharge tube 2 and the end portion 2b on the longitudinal direction are disposed, and the length of the external electrode 31 is long. The edge end portion 31a (the end portion 32a in the longitudinal direction of the external electrode 32) and the end portion 4m in the longitudinal direction of the reflection film 4 and the end portion 31b in the longitudinal direction of the external electrode 31 (the long-side end of the external electrode 32) The portion 32b) has an end portion light-emitting region in which the reflection film 4 is not formed between the end portions 4n in the longitudinal direction of the reflection film 4, and the long-side end portion 31a and the long side of the pair of external electrodes 31 and the external electrode 32. The inner peripheral surface of the direction end portion 31b, the longitudinal end portion 32a, and the long-side end portion 32b has a light-transmitting region Rx in the workpiece direction (hereinafter, simply referred to as a light-transmitting region Rx in the workpiece direction) (see FIG. 4). The light transmitting region Rx in the workpiece direction is wider than the light transmitting region including the workpiece direction of the opening portion 5.

According to the discharge lamp, the amount of light irradiated from the end portion in the longitudinal direction of the discharge lamp can be increased.

Further, the light-transmitting region in the direction of the workpiece is a light-transmitting region which is formed in a discharge tube when the discharge tube is divided into two by a surface HS (see FIG. 3) parallel to the longitudinal direction. Side outer circumference (hereinafter, referred to as the workpiece of the discharge tube) In the area of the side outer circumference).

In other words, the light generated by the discharge in the end portion light-emitting region where the reflection film 4 is not formed can be emitted from the light-transmitting region Rx in the workpiece direction, so that the amount of light irradiated from the end portion in the longitudinal direction of the discharge lamp can be increased. The light transmitting region Rx in the workpiece direction is wider than the light transmitting region including the workpiece direction of the opening portion 5.

Further, a pair of the outer electrode 31, the longitudinal end portion 31a of the outer electrode 32, the longitudinal end portion 31b, the longitudinal end portion 32a, and a part of the longitudinal end portion 32b may be sandwiched between the discharge tubes. It is disposed closer to the longitudinal end portion 2a of the discharge tube 2 and the longitudinal end portion 2b side than the end portion 4m in the longitudinal direction of the reflection film 4 and the end portion 4n in the longitudinal direction.

In addition, the end portion 4m in the longitudinal direction of the reflection film 4, the end portion 4n in the longitudinal direction, the pair of external electrodes 31, the end portion 31a in the longitudinal direction of the external electrode 32, the end portion 31b in the longitudinal direction, and the end portion in the longitudinal direction 32a and the longitudinal direction end portion 32b are at the same position in the longitudinal direction of the discharge tube 2, and similarly, as shown in FIG. 8, the light amount distribution in the longitudinal direction of the illuminated surface (light quantity uniformity) ) is getting worse.

The end portion 4m in the longitudinal direction and the end portion 4n in the longitudinal direction of the reflection film 4 are disposed at the end portion 31a in the longitudinal direction of the pair of external electrodes 31 and the external electrode 32, the end portion 31b in the longitudinal direction, and the end portion in the longitudinal direction. When the longitudinal end portion 32b of the discharge tube 2 is further in the longitudinal direction end portion 2a and the longitudinal end portion 2b side of the discharge tube 2, it can be disposed at the longitudinal end of the pair of external electrodes 31 and the external electrode 32. The portion 31a, the longitudinal end portion 31b, the longitudinal end portion 32a, and the longitudinal end portion 32b are further disposed on the longitudinal end portion 2a of the discharge tube 2 and the reflection film 4 at the side in the longitudinal direction end portion 2b. In a pair of external electrodes 31, The longitudinal end portion 31a, the longitudinal end portion 31b, the longitudinal end portion 32a, and the longitudinal end portion 32b of the external electrode 32 generate and scatter the reflected light, and return to the longitudinal end portion of the previous light emitting portion. Therefore, the amount of light irradiated from the end portion in the longitudinal direction of the discharge lamp can be increased. However, since the pair of electrodes does not exist in the longitudinal end portion 2a of the discharge tube 2 and the longitudinal end portion 2b side, the discharge lamps having the same size in the longitudinal direction of the discharge tube 2 are compared with each other. Then, the amount of light irradiated from the end portion in the longitudinal direction of the discharge lamp must be small.

When the discharge lamp of the present embodiment is formed, the end portion 4m in the longitudinal direction and the end portion 4n in the longitudinal direction of the reflective film 4 serve as discharge spaces, and thus the reflection film at the end portion 4m and the end portion 4n may be feared. In the case of causing the peeling, the end portion 4m and the long-side end of the reflecting film 4 in the longitudinal direction are increased by increasing the adhesive force of the reflecting film 4 at the end portion 4m and the end portion 4n. The size of the inner circumferential surface of the portion 4n is shorter than the size of the inner circumferential surface of the central portion 2c of the longitudinal direction of the discharge tube 2, or the film thickness is reduced, and peeling can be suppressed.

In addition, a discharge lamp in which both ends in the longitudinal direction of the discharge tube shown in FIG. 8 are welded by a quartz block is formed at both ends in the longitudinal direction of the discharge tube due to heat during welding of the quartz block. The problem of peeling off the reflective film.

Further, in the discharge lamp in which the quartz block is welded, ultraviolet rays are irradiated to the welded portion with the use of the discharge lamp, whereby deterioration or cracking of the welded portion is easily caused, and thus both ends in the longitudinal direction of the discharge tube are provided. A light shielding film (light absorbing film) was formed in the portion (Fig. 8).

However, the light shielding film provided at both end portions in the longitudinal direction of the discharge tube hardly has The reflection function has a problem that the amount of light emitted from the end portion in the longitudinal direction of the light emitting portion is further lowered, and the light amount distribution (light amount uniformity) in the longitudinal direction of the illuminated surface is deteriorated (FIG. 8).

In the present invention, the discharge lamp which is formed by welding the both ends of the longitudinal direction of the discharge tube by the quartz block can increase the amount of light irradiated from the end portion in the longitudinal direction of the discharge lamp.

In other words, the discharge lamp 100 of the present embodiment is formed with a light shielding film (light absorbing film) 6 which is provided on the inner end surface (the discharge tube of the left wall portion 25 and the right wall portion 26) which is parallel to the short side direction of the discharge tube 2. The inner surface of 2 and the end portion of the discharge tube 2 in the longitudinal direction and the inner peripheral surface absorb ultraviolet rays and block light. The light shielding film 6 protects the welded portion of the quartz block (the left wall portion 25 and the right wall portion 26) of the discharge tube 2 from ultraviolet rays. Specifically, the light shielding film 6 is formed not only on the inner surface of the upper wall portion 21 constituting the inner circumferential surface of the both end portions 2a and 2b in the longitudinal direction, the inner surface of the lower wall portion 22, and the inner surface of the front wall portion 23. The inner surface of the rear wall portion 24 is also formed on the inner surface of the left wall portion 25 and the inner surface of the right wall portion 26.

The light shielding film 6 can be utilized such that deterioration or cracking due to irradiation of ultraviolet rays to the welded portion of the quartz block is less likely to occur. Further, even if the light-shielding film 6 is not provided and the reflective film is provided to block light, the same effect can be obtained. However, when the reflective film is used, it is necessary to increase the film thickness in order to reliably reflect, and it is difficult to form a film. Moreover, it is difficult to apply uniformly, and unevenness in reflectance occurs. On the other hand, as long as it is a light absorbing film, the film thickness of the extent that light is not transmitted may be sufficient, and the film forming step can be simplified. Moreover, in the case of using a light absorbing film, the influence of reflection is small, and the light amount distribution can be reduced (light Unevenness of the amount of uniformity).

Further, in the discharge lamp 100 of the present embodiment, as shown in FIG. 2 and FIG. 4, in particular, a workpiece direction in which the reflection film 4 and the light shielding film 6 are not provided is formed on the inner circumferential surface between the reflection film 4 and the light shielding film 6. The light-transmitting region Rx in the workpiece direction is wider than the light-transmitting region including the workpiece direction of the opening 5. In other words, the reflection film 4 is provided in the longitudinal direction central portion 2c between the both end portions 2a in the longitudinal direction of the discharge tube 2 and the both end portions 2b in the longitudinal direction.

In the discharge lamp, the discharge lamp in which the both end portions 2a in the longitudinal direction of the discharge tube 2 and the both end portions 2b in the longitudinal direction are welded by the quartz block is less likely to be affected by the light shielding film 6 (light absorption). Therefore, the amount of light irradiated from the end portion in the longitudinal direction of the discharge lamp can be increased.

Further, the light-transmitting region Rx in the workpiece direction mentioned in the present application includes the case where the reflective film 4 and the light-shielding film 6 are formed but the function of each film is low, except that the reflective film 4 and the light-shielding film 6 are not provided. (The reflective film 4 transmits almost without reflection, and if it is the light-shielding film 6, it transmits almost no light, etc.).

In the present embodiment, the reflection film 4 and the light shielding film 6 are not provided on the inner circumferential surface between the reflection film 4 and the light shielding film 6. However, a reflection film may be provided in a region other than the light transmission region in the workpiece direction. 4 and the light shielding film 6, the reflection film 4 and the light shielding film 6 may be provided in a partial region of the light transmission region in the workpiece direction.

The light-transmitting region Rx in the workpiece direction between the reflective film 4 and the light-shielding film 6 is preferably formed over the entire outer peripheral portion of the workpiece side of the discharge tube. If it is the discharge lamp, it is less susceptible to the influence of the light shielding film 6 (light absorption), and further can be processed from the discharge tube. The entire area of the outer peripheral portion of the piece emits light, thereby maximizing the amount of light.

Specifically, in the light-transmitting region Rx of the above-described workpiece direction, the one end portion (left end portion) 4m in the longitudinal direction of the reflective film 4 is spaced apart from the light-shielding film 6 in the longitudinal direction, and the light-shielding film 6 is provided in the discharge tube. The inner surface 251 of the left side wall 25 of the second side (the inner end surface parallel to the short side direction of the discharge tube 2) and the one end portion 2a and the inner peripheral surface of the discharge tube 2 in the longitudinal direction are formed at one end portion in the longitudinal direction of the reflection film 4 A light-transmitting region Rx in the workpiece direction is formed between 4m and the longitudinal end portion 6m of the light-shielding film 6. Further, the other end portion (right end portion) 4n in the longitudinal direction of the reflection film 4 is spaced apart from the light shielding film 6 in the longitudinal direction, and the light shielding film 6 is provided on the inner surface 261 of the right side wall 26 of the discharge tube 2 (with discharge The inner end surface of the tube 2 which is parallel to the short side direction and the other end portion 2b of the longitudinal direction of the discharge tube 2 and the inner peripheral surface thereof are at the other end portion 4n in the longitudinal direction of the reflection film 4 and the longitudinal end of the light shielding film 6. A light transmitting region Rx in the direction of the workpiece is formed between the portions 6n.

In the present embodiment, the light-transmitting region Rx formed in the workpiece direction at one end portion 2a in the longitudinal direction of the discharge tube 2 and the light-transmitting region Rx formed in the workpiece direction formed at the other end portion 2b in the longitudinal direction are along the length. The dimensions in the side direction are the same.

The reflection film 4 thus constituted contains cerium oxide particles. Further, in the method of forming the reflective film 4, the cerium oxide powder is mixed with a predetermined solvent and stirred to prepare a slurry. This slurry is applied to a predetermined portion of the synthetic quartz glass tube constituting the discharge tube 2 (the inner peripheral surface of the central portion 2c of the discharge tube 2 in the longitudinal direction) and dried. In addition, when the slurry is applied to a predetermined portion of the glass tube, the portion where the reflection film 4 is not formed is shielded by a mask or the like. Moreover, in drying the slurry After drying, the mask is peeled off, and the glass tube is fired at, for example, 1000 ° C for a predetermined time, whereby the reflective film 4 is formed. Further, the quartz tube was welded to the opening portions at both ends of the glass tube on which the reflection film 4 was formed, whereby the discharge tube 2 was produced. Further, in a portion corresponding to the light-transmitting region Rx in the workpiece direction, a reflective film is formed in the same manner as the other portions, and the reflective film corresponding to the light-transmitting region Rx in the workpiece direction is melted, so that the reflection function can be prevented without losing the reflection function. A light transmitting region Rx forming a workpiece direction is formed.

The light shielding film 6 contains cerium oxide microparticles. Further, the light shielding film 6 is formed by mixing and stirring the cerium oxide fine particles with a predetermined solvent to prepare a slurry. In the glass tube constituting the discharge tube 2, the slurry is applied to the inner peripheral surface at both end portions of a predetermined portion of the light-transmitting region Rx in which the workpiece direction is formed, and when welding is performed on the welded quartz block. The surface of the inner end surface parallel to the short side direction of the discharge tube 2 is dried. Further, when the slurry is applied to a predetermined portion of a glass tube or a quartz block, the slurry is introduced into the surface of the glass tube or the quartz block by a predetermined amount, and after the glass tube and the quartz block are welded, the glass tube is welded. After the internal pressure is reduced to a predetermined range, for example, it is calcined at 500 ° C for a predetermined time, whereby the light shielding film 6 is formed.

Further, in the discharge lamp 100 of the present embodiment, the pair of external electrodes 31 and the external electrodes 32 are provided on the outer surface of the discharge tube 2 so as to face each other along the longitudinal direction of the light-transmitting region Rx including the workpiece direction.

In other words, the pair of external electrodes 31 and the external electrodes 32 cover a part or all of the light-transmitting region Rx in the workpiece direction and are opposed to each other (see FIGS. 2 and 4: all in the drawing). Thereby, discharge can also be performed in the portion (end portion light-emitting region) where the reflection film 4 is not provided. Moreover, by this, the light of the ultraviolet ray irradiated from the light-transmitting region Rx in the workpiece direction can be increased. the amount.

It is preferable that the pair of external electrodes 31 and the external electrodes 32 are the mesh electrodes 32 provided on the light emitting portion side, and the other is the plate electrode 31.

According to this, the plate electrode 31 can reflect the light generated by the discharge in the end light-emitting region in the direction of the light-emitting portion, so that the amount of light irradiated from the light-transmitting region Rx in the workpiece direction can be further increased.

The light amount distribution in the longitudinal direction of the discharge lamp 100 is shown in FIG. As shown in FIG. 7, the inner peripheral surface of the both end portions 2a in the longitudinal direction of the discharge tube 2 and the both end portions 2b in the longitudinal direction form a light-transmitting region Rx in the workpiece direction, whereby the longitudinal direction of the discharge lamp 100 is obtained. The area where the amount of light on the surface is uniform is large, and the amount of light irradiated from the discharge lamp 100 can be made uniform in the longitudinal direction.

In addition, the light-transmitting region Rx in the workpiece direction is the entire region in the region on the workpiece-side outer peripheral portion of the discharge tube when the discharge tube is divided into two surfaces HS (see FIG. 3) parallel to the longitudinal direction. This can further enhance the effect.

It is preferable that a part of the outer electrode 31 on the side of the longitudinal direction end portion 2b of the discharge tube 2 is formed in the longitudinal direction end portion 4n of the reflection film 4 to emit ultraviolet light to the light amount monitor (not shown). For example, a mesh-shaped monitor window 2W (see FIGS. 1 and 4) is shown.

Therefore, it is possible to control the amount of light to be irradiated from the discharge lamp, and it is not necessary to newly provide a dedicated space for forming a window for the optical monitor, and thus the design becomes easy.

Further, the monitor window may be formed in a part of the outer electrode 32 on the side in the longitudinal direction end portion 2b of the discharge tube 2 from the end portion 4n in the longitudinal direction of the reflection film 4. For example, a mesh-like monitor window 2W for emitting ultraviolet rays to a light amount monitor.

According to the discharge lamp 100 of the present embodiment configured as described above, the light-transmitting region Rx in the workpiece direction is formed at both end portions 2a in the longitudinal direction of the discharge tube 2 and both end portions 2b in the longitudinal direction, so that the discharge tube 2 can be increased. The amount of light that is irradiated to both end portions 2a in the longitudinal direction and both end portions 2b in the longitudinal direction. Therefore, the amount of light irradiated from the discharge lamp 100 can be made uniform in the longitudinal direction. Further, a part of the outer electrode 31 on the side in the longitudinal direction end portion 2b of the discharge tube 2 is formed in the longitudinal direction end portion 4n of the reflection film 4 to emit ultraviolet light to the light amount monitor (not shown). For example, the mesh-shaped monitor window 2W can control the amount of light irradiated from the discharge lamp 100.

The pair of external electrodes 31 and the external electrodes 32 are preferably provided on the outer surface of the discharge tube in the longitudinal direction of the light-transmitting region Rx including the workpiece direction, and are not provided in a region where the light-shielding film is formed.

Specifically, as shown in FIG. 5 and FIG. 6 , the longitudinal end portion 6 m and the longitudinal end portion 6 n of the light shielding film 6 preferably do not include opposing regions that are disposed to face each other along the longitudinal direction of the electrode. Inside.

Thereby, generation of light in the vicinity of the light shielding film 6 can be reduced, and thus deterioration of the light shielding film 6 can be suppressed, and deterioration of the welded portion or generation of cracks can be suppressed.

Further, in this case, there is a possibility that the amount of light irradiated from the end portion in the longitudinal direction of the discharge lamp is lowered. However, when the light shielding film 6 is originally provided in the opposing region of the electrode, the light generated in the opposing region is Since the light-shielding film 6 is absorbed, it is considered that even if it is set as described above, the fall of the amount of light can be suppressed to the minimum.

Further, the present invention is not limited to the above embodiment.

For example, in the above-described embodiment, the light-transmitting region Rx in the workpiece direction is formed at both end portions 2a in the longitudinal direction of the discharge tube 2 and both end portions 2b in the longitudinal direction, but may be two in the longitudinal direction of the discharge tube 2. A light-transmitting region Rx in the workpiece direction is formed on either of the end portion 2a and the both end portions 2b in the longitudinal direction.

Further, the light-transmitting region Rx in the workpiece direction of the one end portion 2a in the longitudinal direction of the discharge tube 2 and the light-transmitting region Rx in the workpiece direction at the other end portion 2b of the longitudinal direction of the discharge tube 2 may be formed along the longitudinal direction. The size is different.

As described above, in the above-described embodiment, the pair of external electrodes 31 and the external electrodes 32 are provided so as to cover all of the light-transmitting regions Rx in the workpiece direction at the end portions in the longitudinal direction of the discharge tube 2, and may be provided only by covering a part thereof. .

Further, the reflective film 4 of the above embodiment contains cerium oxide particles, but may contain alumina particles in addition to the cerium oxide fine particles.

In addition to the dielectric barrier discharge lamp, the discharge lamp may be an ultraviolet lamp such as a low-pressure mercury lamp having a wavelength of 185 nm or 254 nm. Further, the shape of the lamp may be a circular tube having a circular cross section or a rectangular tube having a rectangular cross section, in addition to a flat tube having a rail shape in cross section, or a double tube structure.

In the case where the light-transmitting region Rx in the workpiece direction in which the reflection film is not provided is formed at both end portions in the longitudinal direction, as shown in FIG. 2 of the present embodiment, the corner portion of the angle tube having a rectangular cross section is likely to be generated. Deterioration or cracking is preferred because a circular tube having a circular cross section or a flat tube having a rail shape in cross section is preferably used.

It is to be understood that the invention is not limited thereto, and various modifications may be made without departing from the spirit and scope of the invention.

Claims (4)

A discharge lamp comprising: a discharge tube; a pair of electrodes disposed in the discharge tube along a longitudinal direction of the discharge tube; and a reflective film having a discharge tube along the longitudinal direction of the discharge tube And an end portion of the discharge tube, wherein the pair of electrodes are disposed at at least one end of the discharge tube so as to sandwich an area outside the end portion of the reflection film in the longitudinal direction Thereby formed at a farther outer side than the end portion in the longitudinal direction of the reflective film, and at least a part of the region in the longitudinal direction of the discharge tube in which the end light-emitting region is located is transparent to the workpiece direction a light-transmissive region in the direction of the workpiece wider than a central portion in the longitudinal direction of the discharge tube, in a direction from the workpiece larger than a light-transmitting region in the direction of the workpiece formed by the opening portion In the light transmission region, light generated by discharge at an end portion light-emitting region where the reflection film is not formed is emitted, and both ends in the longitudinal direction of the discharge tube are welded by a quartz block. The discharge lamp according to claim 1, wherein the pair of electrodes are disposed on an outer surface of the discharge tube in a direction along a longitudinal direction including the light transmitting region. The discharge lamp according to claim 2, wherein one of the pair of electrodes is a mesh electrode provided on the opening side, and the other is a plate electrode. The discharge lamp according to any one of the first to third aspect, wherein the pair of electrodes are disposed so as to sandwich an area outside the end portion of the reflection film in the longitudinal direction. A part is used as a window for an optical monitor.