JP2012069350A - Discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp capable of stably radiating an arbitrary amount of ultraviolet ray by using a simple structure and stably radiating the ultraviolet ray having the amount adapted to a purpose.SOLUTION: A cold cathode discharge lamp 1 comprises a glass tube 10 transparent to an ultraviolet ray and visible light, ultraviolet ray radiation gas encapsulated inside the glass tube 10, electrodes 20 (20a, 20b) disposed inside and/or outside the glass tube 10 for causing discharge in the glass tube 10, and phosphor layers 30 (30a, 30b, 30c) formed at a portion of the glass tube 10 for emitting visible light in receipt of the radiation of an ultraviolet ray. A portion of the ultraviolet ray generated in the glass tube 10 is absorbed by the phosphor layers 30. The region forming the phosphor layers 30 is adjusted so as to radiate the ultraviolet ray having the amount according to a purpose.

Description

  The present invention relates to a discharge lamp.

  Ultraviolet rays exhibit an ozone generating action at a wavelength of about 185 nm, a bactericidal action at a wavelength of about 254 nm, and a photocatalytic activation action at a wavelength of about 360 nm. As described above, ultraviolet rays having different actions depending on the wavelength are widely used according to applications.

  In general, a low-pressure discharge lamp is used for generation (radiation) of ultraviolet rays. The low-pressure discharge lamp is composed of a transparent tube, a pair of electrodes disposed at both ends of the transparent tube, and a rare gas containing mercury enclosed in the transparent tube, and causes discharge between the pair of electrodes. Excites mercury atoms and emits ultraviolet rays.

  In the low-pressure discharge lamp, the electrode is sputtered by the discharge. The sputtered electrode material accumulates in the glass tube, blackens the end of the glass tube, and further combines with the enclosed mercury to lower the mercury density and make the discharge unstable.

  In order to solve this problem, Patent Document 1 discloses a technique for forming a metal layer made of the same material as that of an electrode in a region where a sputtered substance is deposited on the inner surface of a glass tube.

  Further, the discharge lamp needs to be irradiated with ultraviolet rays having an intensity corresponding to the purpose of use. Conventionally, the amount of ultraviolet radiation has been set to an appropriate amount by adjusting the length of the discharge lamp. However, this adjustment method cannot flexibly cope with the restrictions on the dimensions of the mounting device. In order to solve this problem, Patent Document 2 discloses that the discharge tube includes a transmission part that transmits ultraviolet light and a non-transmission part that does not transmit ultraviolet light, and adjusts the length of the transmission part and the non-transmission part. An invention is disclosed in which the amount of ultraviolet radiation is adjusted while maintaining the entire length constant.

JP 2009-70775 A JP 7-330308 A

  In the discharge tube disclosed in Patent Document 1, since a metal is disposed in the discharge tube, the structure is complicated, and a useless region that cannot contribute to irradiation with either ultraviolet light or visible light is formed. In addition, the discharge tube disclosed in Patent Document 2 is complicated in manufacture, has low reliability, and it is difficult to stably maintain discharge for a long period of time.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a discharge lamp capable of stably emitting an arbitrary amount of ultraviolet rays with a simple configuration. It is another object of the present invention to provide a discharge lamp that can stably emit an amount of ultraviolet rays suitable for the purpose.

In order to achieve the above object, a discharge lamp according to the present invention comprises:
A tube that transmits ultraviolet and visible light;
Ultraviolet radiation gas sealed inside the tube;
A plurality of electrodes disposed inside and / or outside the tube and causing discharge in the tube;
A phosphor layer that is formed on a portion of the tube and emits visible light upon irradiation with the ultraviolet rays,
It is characterized by irradiating ultraviolet rays and visible light.

  The discharge lamp according to the present invention can stably emit an arbitrary amount of ultraviolet rays with a simple configuration. In addition, according to the low-pressure discharge lamp of the present invention, it is possible to stably emit an amount of ultraviolet rays suitable for the purpose.

It is a schematic sectional drawing at the time of cutting the cold cathode discharge lamp which concerns on 1st Embodiment along the length direction. It is a graph showing the transmittance | permeability curve of the borosilicate glass used with the cold cathode discharge lamp which concerns on 1st Embodiment. It is a schematic sectional drawing at the time of cutting the cold cathode discharge lamp which concerns on 2nd Embodiment along the length direction. RGB (Red-Green-Blue color model) 3-color mixed phosphor Y ₂ O ₃ : Eu, LaPO ₄ : Ce, Tb, BaMg ₂ Al ₁₆ O ₂₇ used in the cold cathode discharge lamp according to the second embodiment: It is the graph showing the relationship between the film thickness of Eu and a wavelength 253.7nm ultraviolet intensity ratio.

  A discharge lamp according to an embodiment for carrying out the present invention will be described by taking a cold cathode discharge lamp as an example.

(First embodiment)
The discharge lamp according to this embodiment is a cold cathode discharge lamp 1 for generating ozone. As shown in FIG. 1, a glass tube 10, an electrode 20, a lead wire 21, a phosphor layer 30, and ultraviolet radiation. Gas 40.

The glass tube 10 is made of ultraviolet transmissive borosilicate glass and has a cylindrical shape with a closed end. The borosilicate glass _{contains SiO 2, B 2 O 3,} Al 2 O 3, Na 2 O, K 2 O, Li 2 O, BaO, and CaO.

SiO ₂ is a component that forms a network of glass. If it is less than 67.5% by weight, the chemical durability of the glass decreases, and conversely, the higher the proportion than 67.5% by weight, The meltability is lowered, and the workability is lowered. For these reasons, the content ratio is preferably 67.5 to 80% by weight. In this embodiment, the borosilicate glass contains 67.5% by weight of SiO ₂ and ensures chemical durability while maintaining sufficient workability.

B ₂ O ₃ is a component used for improving the meltability of the glass and adjusting the viscosity. If it is less than 10% by weight, the meltability is lowered, and tungsten which is a material of the lead wire 21 described later. The sealing property with etc. also decreases. On the other hand, if it exceeds 25% by weight, the chemical durability of the glass decreases. For these reasons, the content ratio is preferably 10 to 25% by weight. In this embodiment, the borosilicate glass contains 20.5 wt% B ₂ O ₃ .

Al ₂ O ₃ is a component used to improve the chemical durability of glass. If it is less than 1% by weight, the chemical durability is lowered, and if it exceeds 10% by weight, the meltability is deteriorated. , The permeability deteriorates. For this reason, the content ratio is preferably 1 to 10% by weight. In this embodiment, the borosilicate glass contains 5% by weight of Al ₂ O ₃ .

Na ₂ O, K ₂ O, and Li ₂ O are components used to improve the solubility of the glass and adjust the expansion coefficient. When the total of these contents is less than 3% by weight, the expansion coefficient is significantly lowered, and the sealing property with tungsten or the like which is a material of the lead wire 21 described later is deteriorated. When it exceeds 10% by weight, chemical durability is deteriorated. For these reasons, the content ratio is preferably 3 to 10% by weight. In this embodiment, the borosilicate glass contains 2.5 wt% Na ₂ O, 2 wt% K ₂ O, and 1 wt% Li ₂ O.

  BaO and CaO are components used for improving the meltability and permeability. By containing substances other than BaO and CaO described above, BaO and CaO can be appropriately contained at a ratio that does not impair the chemical durability that is appropriately maintained. In this embodiment, the borosilicate glass contains 1 wt% BaO and 0.5 wt% CaO.

  As shown in the graph of FIG. 2, the borosilicate glass composed of these substances transmits about 40% of ultraviolet rays having a wavelength of 184.9 nm having an ozone generation function.

  A pair of electrodes 20 (20a, 20b) of the cold cathode discharge lamp 1 shown in FIG. 1 are disposed inside the glass tube 10 so as to face each other at a predetermined interval. Each of the electrodes 20 is formed of a metal such as molybdenum or nickel, an alloy containing them as a main component, or the like, and is formed in a cup shape having one end opened and the other end closed. A lead wire 21 is connected to the closing portion of the electrode 20.

  The lead wires 21 (21a, 21b) are provided at both ends of the glass tube 10 so as to penetrate the tube wall. The lead wire 21 has one end connected to the electrode 20 and the other end connected to an external electrode (not shown). The lead wire 21 is made of a material such as tungsten, kovar, or molybdenum. By sealing the lead wire 21 and the end of the glass tube 10, the inside of the glass tube 10 is kept airtight. Since the expansion coefficient of the borosilicate glass forming the glass tube 10 and the material of the lead wire 21 are close, the lead wire 21 and the glass tube 10 can be easily connected as compared with the case where the glass tube is made of quartz glass or the like. Can be sealed.

  The phosphor layer 30 includes first and second phosphor layers 30a and 30b formed on the inner surface of the glass tube 10, and a third phosphor layer 30c formed on the outer surface. Each of the first to third phosphor layers 30a, 30b, and 30c is formed over the entire circumference with a film thickness necessary for shielding (absorbing) ultraviolet rays.

  The first phosphor layer 30a is formed on one end of the inner surface of the glass tube 10 in a region from the one end to the tip of the tip of the electrode 20a on the other end 20mm.

  The second phosphor layer 30b is formed on the other end of the inner surface of the glass tube 10 in a region from the other end to the tip of the tip of the electrode 20b on the one end side 20 mm.

  The 3rd fluorescent substance layer 30c is formed in the position which does not overlap with the 1st and 2nd fluorescent substance layers 30a and 30b of the outer surface center part of the glass tube 10. FIG.

The first to third phosphor layers 30a to 30c have ultraviolet rays emitted from the cold cathode discharge lamp 1 by the sum of the lengths l _a , l _b , and l _{c in} the tube axis direction (l _a + l _b + l _c ). Are adjusted in advance so that the total amount of emitted ultraviolet rays becomes a predetermined amount. A method for limiting ultraviolet rays will be described later.

Phosphor layer 30 (30 a to 30 c) it _{is, (Y, Gd) BO 3} : Eu and BaO _· 6Al ₂ O 3: is configured to include a Mn. When irradiated with ultraviolet light having a wavelength of 184.9 nm, (Y, Gd) BO ₃ : Eu is a substance having a large emission intensity of red visible light, and BaO · 6Al ₂ O ₃ : Mn is an emission intensity of green visible light. Is a big substance. The proportions of both substances in the phosphor layer 30 are appropriately adjusted, and the phosphor layer 30 emits light of a color that is easily visible to the observer when irradiated with ultraviolet light having a wavelength of 184.9 nm. .

  Application | coating of the fluorescent substance layer 30 (30a-30c) is performed by immersing and pulling up the viscous suspension of the substance which comprises the fluorescent substance layer 30, by immersing the glass tube 10 before edge part sealing. If a resist film made of a predetermined resin is formed in a region other than the region where the phosphor layer 30 is to be formed in the glass tube 10 before sealing, the suspension is dried, and then the resist film is peeled off. 1, the phosphor layer 30 (30a to 30c) can be formed. Since the phosphor layer 30 that limits the amount of ultraviolet radiation can be formed in this way, the cold cathode discharge lamp 1 has a simple configuration.

  The ultraviolet radiation gas 40 is enclosed in an airtight glass tube 10 and is composed of a rare gas such as argon or xenon and mercury.

  The cold cathode discharge lamp 1 is configured as described above, emits ultraviolet rays, and reacts with oxygen in the air to generate ozone. Specifically, the electrodes 20a and 20b are supplied with power from the external electrodes via the lead wires 21 (21a and 21b), and the electrodes 20a and 20b are discharged. A rare gas contributes to the discharge. Mercury is excited by the discharge, and ultraviolet rays are generated in the glass tube 10. Part of the generated ultraviolet rays passes through a region where the phosphor layer 30 (30a to 30c) is not formed and is emitted to the outside of the glass tube 10. Ultraviolet rays having a wavelength of 184.9 nm included in the emitted ultraviolet rays react with oxygen in the air to generate ozone. Of the generated ultraviolet rays, the ultraviolet rays that are not emitted to the outside are absorbed by the phosphor layer 30. The phosphor layer 30 is excited by being irradiated with ultraviolet rays and emits visible light. Thereby, the cold cathode discharge lamp 1 is illuminated.

  The cold cathode discharge lamp 1 according to this embodiment includes a phosphor layer 30 (30a to 30c) formed with a film thickness that blocks ultraviolet rays. Since the ultraviolet rays generated inside the glass tube 10 cannot pass through the phosphor layer 30, the ultraviolet rays pass from the region where the phosphor layer 30 is not formed to the outside of the glass tube 10.

The principle that the amount of ultraviolet radiation of a discharge lamp is generally proportional to the lamp length is generally known. Here, let us consider the amount of ultraviolet radiation of a cold cathode discharge lamp having the same configuration as that of the cold cathode discharge lamp 1 except that the phosphor layer 30 is not provided. If the lamp length of this cold cathode discharge lamp is L, the ultraviolet radiation amount E ₀ can be generally expressed as follows.
(Equation 1)
E ₀ = kL (k is a proportional constant)

On the other hand, the cold cathode discharge lamp 1 according to this embodiment includes a phosphor layer 30 (30a to 30c) formed with a film thickness that blocks ultraviolet rays. Considering that the ultraviolet rays generated inside the glass tube 10 cannot pass through the phosphor layer 30 whose sum in the tube axis direction is (l _a + l _b + l _c ), the above principle is applied. Then, the ultraviolet radiation amount E can be generally expressed as follows, assuming that the conditions such as voltage and electrode size applied to the cold cathode discharge lamp are the same. Note that ε is a contribution rate in consideration of a portion of the phosphor layer 30 that does not contribute to the shielding of ultraviolet rays (such as the end portion side of the glass tube 10 of the first and second phosphor layers 30a and 30b).
(Equation 2)
E = k {L−ε (l _a + l _b + l _c )} (ε <1)

That is, according to the cold cathode discharge lamp 1 including the phosphor layer 30 according to the present embodiment, as can be seen from Equations 1 and 2, the amount of ultraviolet radiation is equal to the amount of ultraviolet radiation when the phosphor layer 30 is not present. It can be limited to {L−ε (l _a + l _b + l _c )} / L times. The cold cathode discharge lamp 1 can radiate an arbitrary amount of ultraviolet rays by previously adjusting the formation region of the phosphor layer 30 in the glass tube 10 by utilizing the limitation of the amount of ultraviolet rays. it can. In the present embodiment, the formation region of the phosphor layer 30 may be adjusted as appropriate so as to emit ultraviolet light that matches the amount of ozone desired to be generated.

  Moreover, according to the cold cathode discharge lamp 1 which concerns on this embodiment, an ultraviolet-ray can be radiated stably. The reason will be described below. In the glass tube 10, a sputtered material that makes discharge and ultraviolet radiation unstable is deposited. When the sputtered material is excessively deposited, mercury in the glass tube 10 is taken into the sputtered material. Then, since the amount of mercury that emits ultraviolet rays decreases, the emission of ultraviolet rays becomes unstable. Further, when the sputter material is excessively deposited, a rare gas is taken into the sputter material. Then, since the amount of rare gas contributing to the discharge is reduced, it becomes easy to cause an abnormality in electrical characteristics, and the discharge becomes unstable. The range in which the sputtered material is easily deposited varies depending on the combination of the three values of the electrode diameters, electrode lengths, and tube current values of the electrodes 20a and 20b. It was found that it was within the range from the end of the glass tube to the tip of the electrode tip on the end side 20 mm. Therefore, in the cold cathode discharge lamp 1 according to the present embodiment, the first and second fluorescent light are deposited in the region from the end of the glass tube 10 to the tip 20 mm of the tip of the electrode 20 on the end side where the sputtered material is likely to be deposited. Body layers 30a and 30b are formed. The first and second phosphor layers 30a and 30b effectively adsorb the sputtered material. Thereby, the reduction | decrease of the noble gas and mercury enclosed in the glass tube 10 can be suppressed, and the state of discharge and the radiation | emission of an ultraviolet-ray can be kept favorable.

  Further, since the cold cathode discharge lamp 1 according to the present embodiment has the first and second phosphor layers 30a and 30b at both ends of the glass tube 10, ultraviolet rays are emitted from both ends of the glass tube 10 to the glass tube. It is possible to suppress the release directly to the outside of 10. For this reason, it is possible to prevent members such as attachment devices around the outside of both ends of the glass tube 10 from being deteriorated by ultraviolet rays.

  Moreover, according to the cold cathode discharge lamp 1 which concerns on this embodiment, the replacement | exchange time of a lamp can be grasped | ascertained appropriately. By irradiating the phosphor layer 30 mainly with ultraviolet light having a wavelength of 184.9 nm, electrons in the substance constituting the phosphor layer 30 are excited, and the phosphor layer 30 emits visible light. Since the visible light emitted from the phosphor layer 30 decreases as the amount of ultraviolet radiation decreases, the observer may know the replacement time of the cold cathode discharge lamp 1 based on the amount of visible light.

(Second Embodiment)
The discharge lamp according to the present embodiment is a cold cathode discharge lamp 2 for sterilization. The configuration of the cold cathode discharge lamp 2 will be described with reference to FIG. Hereinafter, about the structure which is common in the cold cathode discharge lamp 1 of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The cold cathode discharge lamp 2 includes a glass tube 210 and a phosphor layer 230, which are different from the first embodiment.

The glass tube 210 is formed of a borosilicate glass that is excellent in the transmittance of ultraviolet rays having a wavelength of 253.7 nm and different from that used in the first embodiment. This borosilicate glass is formed as a mixture without containing species that oxidize Fe ²⁺ and species that absorb ultraviolet rays, such as nitrates. The glass tube 210 may have the same composition as the borosilicate glass used in the glass tube 10 according to the first embodiment described above. However, in the cold cathode discharge lamp 2, the wavelength is mainly 253.7 nm. Since it is not an essential element that the ultraviolet ray having a wavelength of 184.9 nm is excellent, the borosilicate glass is used in the second embodiment.

  The phosphor layer 230 includes first, second, and third phosphor layers 230a, 230b, and 230c formed on the inner surface of the glass tube 210. Each of the first to third phosphor layers 230a, 230b, and 230c has a film thickness necessary for shielding (absorbing) ultraviolet rays and is formed over the entire circumference. The film thickness of the phosphor layer 230 is appropriately determined according to the purpose in view of the relationship between the ultraviolet transmittance and the film thickness shown in the graph of FIG. 4 and the ultraviolet transmittance of the glass tube 210, for example. The

  The first phosphor layer 230a is formed on one end of the inner surface of the glass tube 210 in a region from the one end to the tip of the tip of the electrode 20a on the other end 20mm.

  The second phosphor layer 230b is formed on the other end portion of the inner surface of the glass tube 210 in a region from the other end portion to the tip 20 mm of the tip of the electrode 20b on the one end side.

  The 3rd fluorescent substance layer 230c is formed in the position which does not overlap with the 1st and 2nd fluorescent substance layers 230a and 230b of the inner surface center part of the glass tube 10. FIG. The third phosphor layer 230c is a group of a plurality of phosphor layers applied at predetermined intervals in the tube axis direction, and is visually recognized by the observer as a vertical stripe pattern in a direction perpendicular to the tube axis direction. The

The lengths of the first and second phosphor layers 230a and 230b in the tube axis direction are represented by l _a and l _b , and the sum of the lengths of the plurality of phosphor layers constituting the third phosphor layer 230c in the tube axis direction is calculated. If Σl, the sum of these (l _a + l _b + Σl) limits the ultraviolet rays emitted from the cold cathode discharge lamp 2 at a desired ratio, so that the total amount of emitted ultraviolet rays becomes a predetermined amount in advance. It is adjusted and formed. A method for limiting ultraviolet rays will be described later.

Phosphor layers 230 (230a~230b) _{is, Y 2 O 3: Eu,} LaPO 4: Ce, Tb, BaMg 2 Al 16 O 27: the so-called RGB (Red-Green-Blue color model) of Eu 3-color mixed phosphor It consists of When irradiated with ultraviolet rays having a wavelength of 253.7 nm, Y ₂ O ₃ : Eu is a substance with a high emission intensity of red visible light, and LaPO ₄ : Ce, Tb has a high emission intensity of yellowish green visible light. BaMg ₂ Al ₁₆ O ₂₇ : Eu is a substance having a high emission intensity of blue visible light. The ratio of these substances in the phosphor layer 230 is appropriately adjusted, and the phosphor layer 230 emits light with a color that is easily visible to the observer when irradiated with ultraviolet rays having a wavelength of 253.7 nm. Emits light.

  The cold cathode discharge lamp 2 is configured as described above to irradiate ultraviolet rays and sterilize an object. Specifically, a part of the ultraviolet rays generated in the glass tube 210 passes through a region where the phosphor layer 230 (230a to 230c) is not formed and is emitted to the outside of the glass tube 210. The object is sterilized by irradiating the object mainly with ultraviolet light having a wavelength of 253.7 nm, which is contained in the emitted ultraviolet light, and destroying DNA (DeoxyriboNucleic Acid) of bacteria and viruses. Note that most of the ultraviolet light having a wavelength of 184.9 nm does not pass through the glass tube 210. Of the generated ultraviolet rays, the ultraviolet rays that are not emitted to the outside are absorbed by the phosphor layer 230. The phosphor layer 230 is excited by being irradiated with ultraviolet rays and emits visible light. Thereby, the cold cathode discharge lamp 2 illuminates.

The cold cathode discharge lamp 2 according to this embodiment includes a phosphor layer 230 (230a to 230c) formed with a film thickness that blocks ultraviolet rays. Considering that the ultraviolet rays generated inside the glass tube 210 cannot pass through the phosphor layer 230 whose sum in the tube axis direction is (l _a + l _b + Σl), the same as in the first embodiment. Thus, the ultraviolet radiation amount E can be expressed as follows.
(Equation 3)
E = k {L−ε (l _a + l _b + Σl)} (ε <1)

That is, according to the cold cathode discharge lamp 2 including the phosphor layer 230 according to the present embodiment, as can be seen from Equations 1 and 3, the amount of ultraviolet radiation is equal to the amount of ultraviolet radiation when the phosphor layer 230 is not present. It can be limited to {L−ε (l _a + l _b + Σl)} / L times. The cold cathode discharge lamp 2 can radiate an arbitrary amount of ultraviolet rays by adjusting the formation region of the phosphor layer 230 in the glass tube 210 in advance by utilizing the limitation of the amount of ultraviolet rays in this way. it can. In the present embodiment, the formation region of the phosphor layer 230 may be adjusted as appropriate so that ultraviolet rays are emitted according to the desired sterilization performance.

  In addition, according to the cold cathode discharge lamp 2 according to the present embodiment, the first and second regions in the region from the end of the glass tube 210 to the tip 20 mm of the end of the electrode 20 on the end side, on which the sputtered material easily deposits. Since the phosphor layers 230a and 230b are formed, ultraviolet rays can be stably emitted.

  Further, according to the cold cathode discharge lamp 2, it is possible to appropriately grasp the lamp replacement time. The phosphor layer 230 emits visible light when the phosphor layer 230 is mainly irradiated with ultraviolet rays having a wavelength of 253.7 nm. Since the visible light emitted from the phosphor layer 230 decreases as the amount of ultraviolet radiation decreases, the observer may know the replacement time of the cold cathode discharge lamp 2 using the amount of visible light as a guide.

(Modification)
In the above embodiment, the discharge lamp according to the present invention is a cold cathode discharge lamp, but is not limited thereto. The discharge lamp may be a hot cathode discharge lamp, an external electrode discharge lamp, or the like.

  Moreover, in the above embodiment, although the example which uses the pipe | tube with which a discharge lamp is equipped as a straight pipe | tube was shown, it is not restricted to this. The tube may be a bent tube such as a U-shape or a W-shape.

  In the above embodiment, the phosphor layer has a film thickness that blocks ultraviolet rays, and the amount of ultraviolet rays emitted by the discharge lamp is adjusted. However, the present invention is not limited to this. The amount of ultraviolet radiation may be adjusted by a combination of the thickness of the phosphor layer that does not completely block ultraviolet radiation and the formation region.

  Moreover, in the above embodiment, although the borosilicate glass was used for the pipe | tube with which a discharge lamp is provided, it is not restricted to this. High-purity synthetic quartz glass excellent in ultraviolet transmittance and other transmission members may be used.

  In the above embodiment, the phosphor is a UVC (UltraViolet C) light emitting phosphor that emits light with an ultraviolet ray having a wavelength of less than 280 nm. However, the present invention is not limited to this. UVA (UltraViolet A) light-emitting phosphor that emits light with a wavelength of 400 to 315 nm, UVB (UltraViolet B) light-emitting phosphor that emits light with a wavelength of 315 to 280 nm, visible light phosphor, and afterglow phosphor Etc. may be appropriately selected according to the application and formed on the tube constituting the discharge lamp.

  In the above embodiment, the example in which the discharge lamp is used as a cold cathode discharge lamp for ozone generation or sterilization has been described, but the present invention is not limited thereto. The discharge lamp may be used as an ultraviolet lamp having a photocatalytic activation effect. In such a case, the phosphor layer is made of a material containing ZnO: Zn, ZnS: Ag, Cu, Ga, Cl or the like that emits visible light upon receiving ultraviolet light having a wavelength of 300 to 400 nm (particularly 360 nm) having a photocatalytic activation effect. What is necessary is just to comprise. Moreover, you may use the fluorescent substance for wavelength conversion which converts the ultraviolet-ray with a wavelength of 300 nm which hardly contributes to photocatalyst activation into the ultraviolet-ray with a wavelength of 300-400 nm suitable for activation of a photocatalyst for a fluorescent substance layer. It should be noted that the phosphor may be formed by appropriately selecting one or more of the substances composing the phosphor described above.

  Moreover, although the fluorescent substance layer was formed in the inner surface and outer surface of the glass tube 10 in 1st Embodiment, and the inner surface of the glass tube 210 in 2nd Embodiment, it is not restricted to this. Unless departing from the spirit of the present invention, for example, in an external cathode discharge lamp or the like, the phosphor may be formed only on the outer surface of the tube.

  In the second embodiment, the third phosphor layer 230c is formed in a vertical stripe shape, but is not limited thereto. A part of the phosphor layer may be formed in a horizontal stripe shape, an oblique stripe shape, a dot shape, or the like. According to the formation mode, the proportion of the phosphor layer in the surface of the tube is appropriately calculated, and the amount of ultraviolet radiation may be adjusted by forming the phosphor layer.

In addition to the phosphor layer, an ultraviolet reflection protective film that is a coating of a metal oxide such as Al, Mg, Gd, La, Zr, and Y is provided between the phosphor layer and the discharge lamp tube. The amount of ultraviolet radiation may be limited by appropriately adjusting the thickness of the phosphor layer.
In addition, regarding the point of emitting an arbitrary amount of ultraviolet rays, the above-described ultraviolet reflection protective film or other components can be used regardless of the phosphor layer, based on the same idea as shown in the above (Equation 2) and (Equation 3). This can be realized by preliminarily coating the tube with an ultraviolet shielding (absorbing) substance.

  Note that the present invention is not construed as being limited by the above embodiments (including the contents of the drawings). It goes without saying that changes (including deletion of components) can be added to the above embodiment.

  A part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.

(Appendix 1)
A tube that transmits ultraviolet and visible light;
Ultraviolet radiation gas sealed inside the tube;
A plurality of electrodes disposed inside and / or outside the tube and causing discharge in the tube;
A phosphor layer that is formed on a portion of the tube and emits visible light upon irradiation with the ultraviolet rays,
A discharge lamp characterized by irradiating ultraviolet rays and visible light.

(Appendix 2)
The phosphor layer is formed in a region where the sputtered material is deposited by the discharge.
The discharge lamp according to supplementary note 1, wherein:

(Appendix 3)
The phosphor layer is formed in a region from the end of the tube to the tip 20 mm of the tip of the electrode on the end side.
The discharge lamp according to supplementary note 1, wherein:

(Appendix 4)
The phosphor layer is formed in a stripe shape,
The discharge lamp according to any one of appendices 1 to 3, characterized in that:

(Appendix 5)
The phosphor layer is formed with a thickness that shields 90% or more of the ultraviolet rays irradiated to the part.
The discharge lamp according to any one of appendices 1 to 4, characterized in that:

(Appendix 6)
The tube is formed of borosilicate glass;
The discharge lamp according to any one of appendices 1 to 5, characterized in that:

(Appendix 7)
The borosilicate glass is SiO ₂ 67.5-80%, B ₂ O ₃ 10-25%, Al ₂ O ₃ 1-10%, Na ₂ O + K ₂ O + Li ₂ O 3-10 by mass%. % And at least BaO and / or CaO,
The discharge lamp according to appendix 6, characterized in that:

1 ... Cold cathode discharge lamp,
10 ... Glass tube 20 ... Electrode (20a, 20b)
21 ... Lead wire (21a, 20b)
DESCRIPTION OF SYMBOLS 30 ... Phosphor layer 30a ... 1st phosphor layer, 30b ... 2nd phosphor layer, 30c ... 3rd phosphor layer 40 ... Ultraviolet radiation gas

2 ... Cold cathode discharge lamp 210 ... Glass tube 230 ... Phosphor layer 230a ... First phosphor layer, 230b ... Second phosphor layer, 230c ... Third phosphor layer

Claims (7)

A tube that transmits ultraviolet and visible light;
Ultraviolet radiation gas sealed inside the tube;
A plurality of electrodes disposed inside and / or outside the tube and causing discharge in the tube;
A phosphor layer that is formed on a portion of the tube and emits visible light upon irradiation with the ultraviolet rays,
A discharge lamp characterized by irradiating ultraviolet rays and visible light. The phosphor layer is formed in a region where the sputtered material is deposited by the discharge.
The discharge lamp according to claim 1. The phosphor layer is formed in a region from the end of the tube to the tip 20 mm of the tip of the electrode on the end side.
The discharge lamp according to claim 1. The phosphor layer is formed in a stripe shape,
The discharge lamp according to any one of claims 1 to 3, wherein: The phosphor layer is formed with a thickness that shields 90% or more of the ultraviolet rays irradiated to the part.
The discharge lamp according to any one of claims 1 to 4, wherein: The tube is formed of borosilicate glass;
The discharge lamp according to claim 1, wherein the discharge lamp is a discharge lamp. The borosilicate glass is SiO ₂ 67.5-80%, B ₂ O ₃ 10-25%, Al ₂ O ₃ 1-10%, Na ₂ O + K ₂ O + Li ₂ O 3-10 by mass%. % And at least BaO and / or CaO,
The discharge lamp according to claim 6.

Images