JP6921557B2 - Discharge lamp and its manufacturing method - Google Patents

Description

The present invention relates to discharge lamps such as excimer lamps and external electrode type fluorescent lamps that emit light by discharge by dielectric barrier discharge or capacitance-coupled high-frequency discharge, and in particular, a phosphor or the like is coated on the inner surface of a small-diameter arc tube in a film shape. Regarding the discharge lamp.

As an excimer lamp, a lamp having a double tube structure in which an arc tube is composed of an inner tube and an outer tube is known. For example, a foil electrode is embedded inside the inner tube along the axial direction, and a dielectric barrier discharge is generated between the foil electrode and the outer electrode arranged on the outer surface of the outer tube to emit light. (See Patent Document 1).

On the other hand, there is known a discharge lamp that emits fluorescence by providing phosphors on the inner surface of the outer tube and the surface of the inner tube in advance and exciting the phosphors with xenon excimer light (see Patent Document 2).

Japanese Unexamined Patent Publication No. 2012-38658 Japanese Unexamined Patent Publication No. 08-228598

In recent years, even in an excimer lamp having a double tube structure, an excimer lamp having a small diameter is required. With such a small-diameter lamp, it is difficult to apply a phosphor or the like in the form of a film. For example, in the method of heat-sealing after applying the fluorescent substance, the fluorescent substance is easily peeled off, and it is difficult to uniformly apply the fluorescent substance to the inner surface of the outer tube and the outer surface of the inner tube. Further, when the fluorescent paint flows into and out of the arc tube through the introduction tube, stagnation and air bubbles remain, and it is difficult to uniformly apply the fluorescent material.

Therefore, it is required to form a film made of a phosphor or the like on the surface of the arc tube in the desired film state.

The discharge lamp of the present invention is coaxially arranged in a bottomed outer tube in which a first introduction tube and a second introduction tube are formed at both ends and an outer tube, and has a convex surface at the end on the side of the first introduction tube. The formed inner tube, a pair of electrodes arranged to face each other with the outer tube and the inner tube interposed therebetween, and a film formed on the inner surface of the outer tube and the surface of the inner tube including the convex surface are provided. The first introduction pipe extends along the axial direction of the outer pipe. The second introduction pipe can be configured to extend along the radial direction of the outer pipe.

For example, the membrane can be composed of a phosphor membrane, which is excited by ultraviolet light emitted in the discharge space to fluoresce. The shape and dimensions of the outer tube and inner tube vary. For example, as a small-diameter discharge lamp, the wall thickness of the outer tube is 0.8 mm to 1.5 mm, the inner diameter of the outer tube is 6 mm to 25 mm, and the thickness of the inner tube. The diameter can be set to be in the range of 0.1 mm to 2 mm and the discharge distance can be set to be in the range of 3 mm to 12.5 mm.

The membrane is adjustable with respect to its axially formed length or thickness, or both length and thickness. For example, the film can be formed so as to be formed halfway along the axial direction from the first introduction pipe side. Further, the thickness of the film can be formed to be different depending on the film forming location. In this case, a relatively thin film portion and a relatively thick film portion can be formed along the axial direction.

In the method for manufacturing a discharge lamp in another aspect of the present invention, a bottomed tubular outer tube is formed, and the outer surface of the tip portion is formed into a convex surface whose diameter is reduced toward the tip side. A step of forming a pipe, a step of providing a first introduction pipe along the axial direction of the outer pipe on the tip side of the outer pipe and a second introduction pipe along the radial direction of the outer pipe on the opening side of the outer pipe. , The process of arranging the outer pipe and the inner pipe coaxially and welding them integrally at the rear end on the opening side of each to form a discharge space, inflowing and flowing out the paint from the first introduction pipe. This includes a step of forming a film on the inner peripheral surface of the outer tube, the outer peripheral surface of the inner tube, and the convex surface of the tip of the inner tube.

For example, a step of removing the film from the inner surfaces of the first introduction tube and the second introduction tube, a step of exposing the inner surfaces of the first introduction tube and the second introduction tube to the discharge space, a step of vacuuming the discharge space, and discharging. A step of filling the gas and a step of airtightly sealing the first introduction pipe and the second introduction pipe by heating and melting may be included.

The method for forming a discharge lamp film (film formation) in another aspect of the present invention is formed on an arc tube having a bottomed first introduction tube and a second introduction tube formed at both ends, and on the inner surface of the arc tube. A method for forming a film of a discharge lamp in which the first introduction tube extends along the axial direction of the outer tube and the second introduction tube extends along the radial direction of the outer tube. , The suction period when the membrane material is sucked from the first introduction tube, and / or the membrane material so that the axial length and / or thickness of the membrane is a predetermined length and / or thickness. 1 Adjust the outflow rate when outflowing from the introduction pipe.

According to the present invention, in a discharge lamp, a film made of a phosphor or the like can be formed on the surface of the arc tube in a desired film state.

It is the schematic sectional drawing of the discharge lamp which is 1st Embodiment. It is a figure which showed the manufacturing process of a discharge lamp. It is the schematic sectional drawing of the discharge lamp which is 2nd Embodiment. It is the schematic sectional drawing of the discharge lamp in the 3rd Embodiment. It is the schematic sectional drawing of the discharge lamp which is 4th Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of the discharge lamp according to the first embodiment.

The discharge lamp 10, which is an excimer lamp, emits light that forms a discharge space S by integrally welding a bottomed tubular outer tube 20 and an inner tube 50 made of a dielectric material such as quartz glass at a sealing portion 53. A tube 11 is provided, and a phosphor film C (film) is coated on the inner surface of the arc tube 11.

The tip of the outer tube 20 (hereinafter referred to as the tip of the outer tube) 21, which is the tip of the arc tube 11, has a first introduction tube (hereinafter, referred to as the outer tube 20) coaxial with the arc tube 11 (outer tube 20). A first introduction pipe) 61 is arranged. Further, a second introduction is introduced into the rear end portion (hereinafter, referred to as the rear end portion of the outer tube) 22 of the outer tube 20 which is the rear end of the arc tube 11 along the radial direction of the arc tube 11 (outer tube 20). A pipe (hereinafter referred to as a second introduction pipe) 62 is arranged.

The outer surface of the tip portion of the inner pipe 50 (hereinafter referred to as the tip portion of the inner pipe) 51 is reduced in diameter toward the bottom surface side (tip side) of the inner pipe at a position facing the opening of the first introduction pipe 61. It has a convex surface. That is, the inner tube tip 51 has a hemispherical shape in which the outer diameter becomes smaller toward the tip side (opposite side of the sealing portion 53) of the discharge lamp 10. The inner tube tip 51 may have a cannonball shape (oval shape), a tapered shape (triangle shape), or the like.

By using the inner tube tip 51 having such a shape, when the paint flows in and out of the arc tube, no stagnation or air bubbles are generated near the outer surface of the inner tube tip 51, and only the inner tube tip 51 is used. However, it is possible to prevent a state in which the film thickness becomes large or a state in which the film is not applied.

The inner surface of the outer tube 20 (the inner peripheral surface of the cylindrical portion of the outer tube 20), the outer surface of the inner tube 50 (the outer peripheral surface of the cylindrical portion of the inner tube 50), and the convex surface of the inner tube tip 51. A phosphor film C is applied to the surface exposed to the discharge space S of the above. On the other hand, the phosphor film C is not applied to the inner surfaces of the first introduction tube 61 and the second introduction tube 62 exposed to the discharge space S.

A rare gas such as xenon gas or a mixed gas thereof is sealed in the discharge space S as a discharge gas. The filling pressure of the discharge gas is set to, for example, 5 kPa to 150 kPa.

Inside the inner tube 50, a band-shaped inner electrode 30 made of a metal foil extending along the axial direction of the discharge lamp 10 is arranged. The inner electrode 30 is covered with an inner tube 50 which is a dielectric material without being exposed to the discharge space S.

The outer electrode 40 is composed of a mesh-like or spiral conductive member so as to transmit light radiated from the discharge space S, and is a dielectric material so as to face the inner electrode 30 in the radial direction. It is arranged along.

The feeder line 70 connected to the end of the inner electrode 30 is connected to a power supply unit (not shown) installed outside, and power is supplied to the discharge lamp 10 via the feeder line 70.

The polarities of the inner electrode 30 and the outer electrode 40 are set to the anode and the cathode, respectively, and are arranged to face each other with the arc tube 11 which is a dielectric interposed therebetween. When a voltage of several kV is applied to the discharge lamp 10, a dielectric barrier discharge occurs between the inner electrode 30 and the outer electrode 40, and excimer light having a predetermined spectrum (for example, a wavelength of 172 nm) is emitted. The phosphor film C coated on the discharge lamp 10 is excited by excimer light (ultraviolet rays) radiated in the discharge space S to emit fluorescence. The discharge distance at this time is 3 mm to 12.5 mm (preferably 3 mm to 10 mm) in order to prevent the discharge distance from becoming narrow and insufficient illuminance, while preventing the discharge distance from becoming long and causing discharge instability. It is better to set it in the range of.

The axial length of the outer tube 20 is set to 100 mm to 300 mm (preferably 100 mm to 250 mm). On the other hand, the wall thickness of the outer tube 20 is set to 0.8 mm to 1.5 mm in order to prevent deterioration of the outer tube due to excimer light and to suppress an increase in the discharge start voltage. The inner diameter of the outer tube 20 is set to 6 mm to 25 mm (preferably 8 mm to 20 mm) so as to prevent both discharge instability due to a long discharge distance and insufficient illuminance due to a short discharge distance.

The thickness of the inner electrode 30 is set to 20 μm to 50 μm in consideration of current capacity, ease of manufacture, prevention of peeling due to thermal expansion, and the like. The width of the foil is set to 1.2 mm to 10 mm in consideration of current capacity, ease of manufacture, and prevention of blocking of synchrotron radiation due to an enlarged electrode area. As the material of the inner electrode 30, molybdenum, an alloy containing the molybdenum, or the like is used.

_{The inner tube 50 is made of a dielectric material (SiO 2} or the like) that is as close as possible to the coefficient of thermal expansion of the inner electrode 30. The thickness of the inner tube 50 is set to 0.1 mm to 2 mm in consideration of the limit for maintaining the insulating property and the prevention of the discharge start voltage from rising.

FIG. 2 is a diagram showing a manufacturing process of the discharge lamp 10. The method for manufacturing the discharge lamp 10 of the present invention will be described below.

The tip of the quartz tube to be the inner tube 50 is heat-sealed, and the bottomed tubular inner tube 50 is formed so that the outer surface of the inner tube tip has a convex surface whose diameter is reduced toward the tip side. As a result, the inner tube tip portion 51 is provided. Then, the feeder line 70 is connected to the inner electrode 30 by resistance welding or the like, and is inserted into the inner tube 50 (step (1)). At this time, after inserting the inner electrode 30, the inside of the inner tube 50 may be evacuated, heated from the outside, and welded to the inner electrode 30 to form a convex surface. Alternatively, the step of coating the inner electrode 30 with the dielectric film may be performed instead to form the convex surface.

A collar-shaped so-called abacus-shaped sealing portion 53 is formed at a position of the inner pipe 50 that is welded to the rear end portion 22 of the outer pipe (step (2)).

The outer tube tip 21 is provided by forming a bottomed tubular outer tube 20 by heating and reducing the diameter of one end of the quartz tube to be the outer tube 20. The outer tip portion 21 may have a cross-sectional shape other than the shape shown in FIG. 2, and may be formed in a tapered shape (funnel shape) whose diameter is reduced toward the first introduction pipe 61, for example. The rear end portion 22 of the outer pipe to be welded to the sealing portion 53 of the inner pipe 50 is opened. The outer tube tip 21 which is the tip of the arc tube 11 is provided with a first introduction tube 61 along the axial direction of the outer tube 20. A second introduction tube 62 along the radial direction of the outer tube 20 is provided on the rear end 22 side of the outer tube, which is the rear end of the arc tube 11 (step (3)).

The second introduction pipe 62 is provided on the rear end portion 22 side of the outer pipe, but when the outer pipe 20 and the inner pipe 50 are heat-welded, the opening of the second introduction pipe 62 may be heat-sealed. Therefore, the second introduction pipe 62 is oriented along the radial direction of the outer pipe 20 and is from the rear end portion 22 of the outer pipe to the tip of the outer pipe so as not to interfere with the heat welding of the inner pipe 50 with the sealing portion 53. It is good to be away from the part 21 side. Further, since the second introduction tube 62 may block the light emitted from the discharge space S, the effective light emitting range along the axial direction (the range in which the outer electrode 40 and the inner electrode 30 face each other in the radial direction). It is preferable to provide it on the rear end 52 side.

The inner tube 50 is inserted into the outer tube 20 and arranged coaxially, and the rear end 22 of the outer tube and the sealing portion 53 on each opening side are integrally heat-welded to form the arc tube 11. (Step (4)).

By sucking from the second introduction tube 62, the inside of the arc tube 11 is put into a negative pressure state, and the fluorescent paint is applied to the inner surface of the arc tube 11 by flowing in and out of the phosphor paint from the first introduction tube 61. , Provide a phosphor film. After that, the phosphor film is removed from the inner surfaces of the first introduction tube 61 and the second introduction tube 62, and the inner surfaces of the first introduction tube 61 and the second introduction tube 62 are exposed to the discharge space S (step (5). )).

At this time, by providing the outer surface of the inner tube tip 51 at a position facing the first introduction tube 61, the phosphor film is homogeneous with respect to the circumferential direction of the inner surface of the outer tube 20 and the outer surface of the inner tube 50. Can be applied. Further, since the outer surface of the inner tube tip 51 is made into a convex surface whose diameter is reduced toward the tip side, when the fluorescent paint flows in and out of the arc tube 11, it stays in the vicinity of the inner tube tip 51. Since no bubbles or bubbles remain, it is possible to prevent a portion having a large film thickness from being locally provided on the tip portion 51 of the inner tube, and the phosphor film is uniformly formed in the axial direction, the radial direction, and the circumferential direction of the discharge lamp. C can be applied.

By exposing the inner surfaces of the first introduction pipe 61 and the second introduction pipe 62 to the discharge space S, the sealing is ensured in the subsequent step of airtightly sealing the first introduction pipe 61 and the second introduction pipe 62. This can be done, and the occurrence of cracks starting from the first introduction pipe 61 and the second introduction pipe 62 can be prevented.

One of the first introduction tube 61 and the second introduction tube 62 is hermetically sealed by heating and melting, and the inside of the arc tube 11 (discharge space S) is evacuated from the other introduction tube to remove impurities. .. At this time, vacuum may be drawn from both introduction pipes. Then, the discharge gas is sealed inside the arc tube 11 through the introduction tube that is not airtightly sealed, and the introduction tube used for vacuuming and filling the discharge gas is airtightly sealed by heating and melting (step (6)). The outer electrode 40 is arranged on the outer surface of the arc tube 11 (step (7)).

In the present embodiment, a first introduction pipe along the axial direction is provided at the tip of the outer pipe, and a second introduction pipe along the radial direction is provided at the rear end of the outer pipe. Further, the outer surface of the tip portion of the inner pipe is a convex surface facing the first introduction pipe and reducing the diameter toward the tip side. As a result, when the fluorescent paint flows in and out of the arc tube, no stagnation or air bubbles remain, and the fluorescent substance can be uniformly applied to the inner surface of the arc tube of the small-diameter discharge lamp. It is possible to provide a discharge lamp having good radiation efficiency due to a phosphor.

Further, by exposing the inner surfaces of the first introduction pipe and the second introduction pipe to the discharge space, the sealing can be surely performed in the subsequent step of heating and sealing the introduction pipe, so that the introduction pipe is the starting point. It is possible to prevent the occurrence of cracks and improve the reliability of the discharge lamp coated with the phosphor.

According to such a small-diameter excimer lamp, a discharge lamp that emits two ultraviolet rays can be configured. Hereinafter, a discharge lamp coated with a phosphor film will be described with reference to FIGS. 3 to 5.

The discharge lamp according to the second embodiment will be described with reference to FIG. In the second discharge lamp, a phosphor film is provided so as to radiate two ultraviolet rays to the outside of the lamp. In the following, the same reference numerals are used for the same components as those in the first embodiment.

FIG. 3 is a schematic cross-sectional view of the discharge lamp according to the second embodiment.

Here, the discharge lamp 10'is an excimer lamp including an arc tube (discharge tube) 11, an inner electrode 30, and an outer electrode 40, and can be used as a light source for sterilization, sterilization, and deodorization. The arc tube 11 is a discharge tube having a double tube structure including a bottomed tubular outer tube 20 and an inner tube 50 made of a dielectric material such as quartz glass, and is integrally welded at the sealing portion 53. To form a discharge space S. A rare gas such as xenon gas or a mixed gas thereof is sealed in the discharge space S as a discharge gas. The filling pressure of the discharge gas is set to, for example, 5 kPa to 150 kPa.

A phosphor film C (film) is applied to the surface of the arc tube 11 over substantially the entire surface. More specifically, the inner surface of the outer tube 20 (the inner peripheral surface of the cylindrical portion of the outer tube 20) 20I and the outer surface of the inner tube 50 (the outer peripheral surface of the cylindrical portion of the inner tube 50) 50S are fluorescent. Body C is applied in the form of a film. Further, the phosphor C is composed of a phosphor C1 coated on the inner surface 20I of the outer tube 20 and a phosphor C2 coated on the outer surface 50S of the inner tube 50, and has a substantially uniform thickness.

Regarding the application of the phosphor C, for example, a fluorescent substance introduction tube is provided at both ends of the outer tube 20, one introduction tube is put into a viscous phosphor solution, and the fluorescent substance C is sucked up and discharged from the other introduction tube. Thereby, the phosphor C can be applied to the surface of the arc tube 11. Alternatively, the phosphor C may be applied in advance to the inner surface 20I of the outer tube 20 and the outer surface 50S of the inner tube 50, and then the arc tube 11 having a double tube structure may be formed.

Inside the inner tube 50, a band-shaped inner electrode 30 made of a metal foil extending along the axial direction of the discharge lamp 10'is arranged. The inner electrode 30 is covered with an inner tube 50 which is a dielectric material without being exposed to the discharge space S. The feeder line 70 connected to the end of the inner electrode 30 is connected to a power supply unit (not shown) installed outside, and power is supplied to the discharge lamp 10 via the feeder line 70.

The outer electrode 40 is composed of a mesh-like or spiral conductive member so as to transmit light radiated from the discharge space S, is not exposed to the discharge space S, and is a dielectric material so as to face the inner electrode 30 in the radial direction. It is arranged in the axial direction along the outer surface 20S of the outer tube 20.

The polarities of the inner electrode 30 and the outer electrode 40 are set to the anode and the cathode, respectively, and are arranged to face each other with the arc tube 11 which is a dielectric interposed therebetween. When a voltage of several kV is applied to the discharge lamp 10', a dielectric barrier discharge occurs between the inner electrode 30 and the outer electrode 40, and ultraviolet rays having a wavelength of 172 nm are radiated as excimer light. The thickness of the film of the phosphor C is such that ultraviolet rays having a wavelength of 172 nm can be transmitted, and at least a part of the ultraviolet rays having a wavelength of 172 nm is transmitted to the outside of the lamp through the phosphor C.

Oxygen (O ₂ ) in air has a light absorption spectrum in the wavelength range of 100 nm to 240 nm. Therefore, oxygen (O ₂ ) outside the lamp absorbs ultraviolet rays (first ultraviolet rays) having a wavelength of 172 nm radiated from the discharge lamp 10', and undergoes photodecomposition of two oxygen atoms (O) to ozone molecules (O _3). ) (First product) is produced.

On the other hand, when the phosphor C receives ultraviolet rays having a wavelength of 172 nm, it emits fluorescence having a wavelength of 250 nm (second ultraviolet rays), whereby the ultraviolet rays having a wavelength of 250 nm are radiated from the phosphor C to the outside of the lamp. Ozone molecules _{(O 3),} have a light absorption spectrum in the wavelength range of 200- 300nm. Therefore, the ozone generated by ultraviolet irradiation of wavelength 172 nm _{(O 3)} absorbs ultraviolet radiation wavelength 250nm to the lamp outside.

As a result, excited state oxygen (second product) such as singlet oxygen atoms and singlet oxygen molecules in the excited state having higher energy than the ground state is generated outside the lamp. Excited state oxygen is active oxygen in a very highly active state, and can perform actions such as deodorization, bleaching, sterilization, and surface oxidation on an object.

As described above, in the present embodiment, in the discharge lamp 10'provided with the arc tube 11 having a double tube structure, the surface of the arc tube 11 (the outer surface 50S of the inner tube 50 and the inner surface 20I of the outer tube 20) is relative to the surface of the arc tube 11. The phosphor C, which receives ultraviolet rays having a wavelength of 172 nm and emits fluorescence having a wavelength of 250 nm, is thinly coated over the entire surface with a substantially uniform thickness. As a result, ultraviolet rays having wavelengths of 172 nm and 250 nm are both emitted from the entire outer surface 50S of the outer tube 20 which is the radiation surface of the arc tube 11. By radiating two ultraviolet rays from the same radiation surface region, both ozone and excited state oxygen can be generated as active oxygen.

The discharge lamp may radiate ultraviolet rays having a wavelength other than 172 nm, and may be ultraviolet rays in the range of the light absorption spectrum of _{oxygen (O 2) (wavelength range of about 100 nm to 240 nm).} Further, even in the phosphor C, excited by ultraviolet radiation due to discharge, wavelength than ultraviolet due to discharge is long, emits ultraviolet light in ozone (wavelength range of approximately 200- 300nm) range of the light absorption spectra of (O ₃₎ It may be configured as follows. Further, it is also possible to configure either the inner surface 20I of the outer tube 20 or the outer surface 50S of the inner tube 50 without applying a fluorescent substance.

Next, the discharge lamp according to the third embodiment will be described with reference to FIG. In the third embodiment, ultraviolet rays having a wavelength of 172 nm and ultraviolet rays having a wavelength of 250 nm are emitted from different radiation surface regions. Other than that, it is substantially the same as the second embodiment.

FIG. 4 is a schematic cross-sectional view of the discharge lamp according to the third embodiment.

The phosphor C'of the discharge lamp 10 "is applied only to the surface region facing the outer surface (radiating surface region) 20A of the left half of the outer tube 20 and facing the outer surface 20B of the right half of the outer tube 20. The fluorescent substance C'1 is not applied to the surface region to be coated. The fluorescent substance C'1 is applied to the inner surface 20I of the outer tube 20 and the phosphor C'2 is applied to the outer surface 50S of the inner tube 50. Consists of.

Further, the phosphor C'is not in the form of a thin film as in the first embodiment, but has a thickness that does not allow ultraviolet rays having a wavelength of 172 nm to pass through. Therefore, the ultraviolet rays having a wavelength of 172 nm radiate from the radiation surface region 20B to the outside of the lamp, while the ultraviolet rays having a wavelength of 250 nm radiate from the radiation surface region 20A to the outside of the lamp.

By selectively radiating ultraviolet rays having a wavelength of 172 nm and ultraviolet rays having a wavelength of 250 nm in different radiation regions in this way, it is possible to adjust the balance between the amount of ozone and the amount of oxygen produced in the excited state. Here, the radiation surface region of the arc tube 11 is substantially bisected along the axial direction, but the ratio can be adjusted by adjusting the axial length to which the phosphor C'is applied. can. For example, in the method of sucking up from the fluorescent liquid surface, the height along the axial direction of the phosphor C'is adjusted by adjusting the sucking period, and the coating range along the axial direction of the phosphor C'can be adjusted. can.

Next, the discharge lamp according to the fourth embodiment will be described with reference to FIG. In the fourth embodiment, a radiation surface region that emits ultraviolet rays having a wavelength of 172 nm and a radiation surface region that emits ultraviolet rays having a wavelength of 250 nm are divided into a plurality of parts.

FIG. 5 is a schematic cross-sectional view of the discharge lamp according to the fourth embodiment.

The phosphor C "of the discharge lamp 100 is entirely coated in the arc tube 11 as in the first embodiment. On the other hand, the fluorescent substance C" has a thin film-like portion whose thickness is not constant. It is composed of (thin portion) CA and CB and thicker portions (thick portion) C1, C2 and C3. The thin portions CA and CB and the thick portions C1, C2 and C3 are formed alternately along the axial direction.

By applying the phosphor C "into the arc tube 11 in this way, it is possible to radiate ultraviolet rays having a wavelength of 172 nm and ultraviolet rays having a wavelength of 250 nm from the radiation surface regions arranged alternately. That is, the thin portion CA, While ultraviolet rays having a wavelength of 172 nm are radiated from the CB to the outside of the lamp, ultraviolet rays having a wavelength of 172 nm are not transmitted from the thick portions C1, C2, and C3, so only ultraviolet rays having a wavelength of 250 nm are radiated from the phosphor C ”to the outside of the lamp. The coating of the phosphor C "can be formed as shown in FIG. 5 by gradually changing the rate of lowering the phosphor liquid level in, for example, a suction method from the phosphor liquid level. The slower the coating, the thicker the coating, and the faster the speed, the thinner the coating. The speed adjustment is realized by providing a valve in the introduction pipe portion to open and close it.

10 Discharge lamp 11 Light emitting tube 20 Outer tube 30 Inner electrode 40 Outer electrode 50 Inner tube C Fluorescent film

Claims (11)

A bottomed outer pipe with a first introduction pipe and a second introduction pipe formed at both ends, and
An inner tube coaxially arranged in the outer tube and having a convex surface formed at the end on the side of the first introduction tube.
A pair of electrodes arranged to face each other with the outer tube and the inner tube interposed therebetween,
A film formed on the inner surface of the outer tube and the surface of the inner tube including the convex surface is provided.
The first introduction pipe extends along the axial direction of the outer pipe ,
The membrane is excited by ultraviolet rays radiated from the discharge space between the inner tube and the outer tube to fluoresce.
A discharge lamp characterized in that the thickness of the film is adjusted to a thickness that transmits ultraviolet rays radiated from the discharge space. A bottomed outer pipe with a first introduction pipe and a second introduction pipe formed at both ends, and
An inner tube coaxially arranged in the outer tube and having a convex surface formed at the end on the side of the first introduction tube.
A pair of electrodes arranged to face each other with the outer tube and the inner tube interposed therebetween,
A film formed on the inner surface of the outer tube and the surface of the inner tube including the convex surface is provided.
The first introduction pipe extends along the axial direction of the outer pipe ,
The second introduction tube extends along the radial direction of the outer tube, and is closer to the outer tube end side than the effective light emitting range in which the pair of electrodes are arranged to face each other, and the outer tube is tapered. discharge electric lamps you being located on the lamp axis center side than the end portion. The film according to claim 1 or 2 , wherein the film is formed halfway along the axial direction from the first introduction tube side in an effective light emitting range in which the pair of electrodes are arranged to face each other. Discharge lamp. A bottomed outer pipe with a first introduction pipe and a second introduction pipe formed at both ends, and
An inner tube coaxially arranged in the outer tube and having a convex surface formed at the end on the side of the first introduction tube.
A pair of electrodes arranged to face each other with the outer tube and the inner tube interposed therebetween,
A film formed on the inner surface of the outer tube and the surface of the inner tube including the convex surface is provided.
The first introduction pipe extends along the axial direction of the outer pipe ,
The thickness of the film is different from that to said discharge electric lamps by film forming portion. A bottomed outer pipe with a first introduction pipe and a second introduction pipe formed at both ends, and
An inner tube coaxially arranged in the outer tube and having a convex surface formed at the end on the side of the first introduction tube.
A pair of electrodes arranged to face each other with the outer tube and the inner tube interposed therebetween,
A film formed on the inner surface of the outer tube and the surface of the inner tube including the convex surface is provided.
The first introduction pipe extends along the axial direction of the outer pipe ,
Relatively thin film portion and relatively thick film portion, discharge electric lamps you characterized in that it is formed along the axial direction. The ultraviolet rays radiated from the discharge space are ultraviolet rays in the wavelength range of the light absorption spectrum of oxygen.
The discharge lamp according to claim 1 , wherein the film has a wavelength longer than that of ultraviolet rays and emits fluorescence having a wavelength in the range of the light absorption spectrum of ozone. The wall thickness of the outer tube is 0.8 mm to 1.5 mm,
The inner diameter of the outer tube is 6 mm to 25 mm,
The thickness of the inner tube is 0.1 mm to 2 mm,
The discharge lamp according to any one of claims 1 to 6 , wherein the discharge distance is set within the range of 3 mm to 12.5 mm. The discharge lamp according to any one of claims 1 to 7, wherein the outer diameter of the outer tube is constant between both ends of the outer tube that are tapered. The process of forming a bottomed tubular outer tube,
A process of forming a bottomed tubular inner tube having a convex surface whose diameter is reduced toward the tip side from the outer surface of the tip.
The step of inserting the inner electrode into the inner tube,
A step of providing a first introduction pipe along the axial direction of the outer pipe on the tip end side of the outer pipe and a second introduction pipe along the radial direction of the outer pipe on the opening side of the outer pipe.
A step of forming a discharge space by arranging the outer tube and the inner tube coaxially and welding them integrally at the rear end portion on the opening side of each.
A step of forming a film on the inner peripheral surface of the outer pipe, the outer peripheral surface of the inner pipe, and the convex surface of the tip of the inner pipe by inflowing and flowing out the paint from the first introduction pipe .
Look including the step of disposing the outer electrode on the outer surface of said outer tube,
In the step of providing the first introduction tube and the second introduction tube, the outer tube is tapered on the outer tube end side of the effective light emitting range in which the outer electrode and the inner electrode are arranged to face each other. A method for manufacturing a discharge lamp , which comprises providing the second introduction pipe so as to be located on the center side of the lamp shaft with respect to the end portion. In the method for manufacturing a discharge lamp according to claim 9,
A step of removing the film from the inner surfaces of the first introduction tube and the second introduction tube.
A step of exposing the inner surfaces of the first introduction pipe and the second introduction pipe to the discharge space.
The process of evacuating the discharge space and filling the discharge gas.
A method for manufacturing a discharge lamp, which comprises a step of airtightly sealing the first introduction pipe and the second introduction pipe by heating and melting. An arc tube having a bottomed first introduction tube and a second introduction tube formed at both ends thereof and a film formed on the inner surface of the arc tube are provided, and the first introduction tube is a shaft of the arc tube. A method of forming a film of a discharge lamp in which the second introduction tube extends along the radial direction of the arc tube.
The suction period and / or the material of the membrane when sucking the material of the membrane from the first introduction tube so that the axial length and / or thickness of the membrane has a predetermined length and / or thickness. A method for forming a film of a discharge lamp, which comprises adjusting the outflow rate when the is discharged from the first introduction pipe.

Images