JP2007053117A - External electrode discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an external electrode discharge lamp with increased quantity of light emission and an extended service life. <P>SOLUTION: This external electrode discharge lamp 13 includes electrodes 70 and 80 formed at the outer peripheral parts of both axial ends of a tubular glass lamp container 20 filled with a discharge medium inside. In the external electrode discharge lamp, the electrodes comprise: conductive layers 35 and 45 attached to the outer periphery of the glass lamp container by adhesives 34 and 44; and contacting metal conductors 90 and 100 attached to the outside peripheries of the conductor layers. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an external electrode discharge lamp in which electrodes are formed on outer peripheral portions at both axial ends of a tubular glass lamp vessel in which a discharge medium is enclosed.

  As a backlight of a liquid crystal display, a dielectric barrier discharge low-pressure discharge lamp (in this specification, provided with electrodes on the outer circumferences of both ends of a tubular glass lamp vessel, as described in Japanese Utility Model Laid-Open No. 61-126559, (Referred to as “external electrode discharge lamp”).

This conventional external electrode discharge lamp 10 has the configuration shown in FIG. 8 and is filled with ionizable gas such as a rare gas or a mixed gas of mercury and a rare gas inside a tubular glass lamp vessel 20 sealed at both ends. The agent 50 is encapsulated, the phosphor layer 60 is formed on the inner peripheral surface of the glass lamp container 20, and the conductive wires 30 and 40 are wound around the outer periphery of the glass lamp container 20 as electrodes 70 and 80 in a coil shape. Yes.
Japanese Utility Model Publication No. 61-126559

In general, the external electrode discharge lamp can be regarded as a capacitor like the equivalent circuit shown in FIG. In the case of a capacitor, the capacitance C is expressed as shown in Equation 1.

  Where ε is the dielectric constant of the glass container, S is the effective area of the external electrode, and d is the thickness of the glass container.

  Thus, if the specification of the glass lamp container 20 is constant, the capacity C is approximately proportional to the area S of the external electrode.

  However, in the above-described conventional external electrode discharge lamp, since the area of the electrodes 70 and 80 can be taken only by the line contact area of the coil, the electrode area S cannot be increased, and the amount of light emission cannot be increased accordingly. There was a point.

  In order to improve the light emission amount of the external electrode discharge lamp, it is necessary to increase the electrode area. For this purpose, a dielectric barrier discharge type low-pressure discharge lamp employing electrodes 70 and 80 as shown in FIG. 10 is considered. It is done. The configuration of the external electrode discharge lamp 11 shown in FIG. 10 is the same as that of FIG. 8 inside the glass lamp container 20, but aluminum tape is used as the electrodes 70 and 80, and the outer periphery of both ends of the glass lamp container 20 is used. It is wound around. Therefore, the electrodes 70 and 80 have a structure in which the foil-like metal conductors 31 and 41 are adhered by the acrylic adhesives 33 and 43.

  With this configuration, the area S of the electrodes 70 and 80 can be increased as described above, and the amount of light emitted as a discharge lamp can be improved.

  However, the external electrode discharge lamp having the configuration shown in FIG. 10 has the following problems to be improved. This is because the acrylic adhesives 33 and 43 for adhering the metal conductors 31 and 41 used as the electrodes 70 and 80 to the glass lamp container 20 are carbonized under high temperature conditions accompanying light emission, resulting in uneven surface resistance. The current concentrates on the part where the resistance value is locally lowered, the hole is generated in the part where the current of the glass lamp container 20 is concentrated and the adhesive strength of the adhesive is weakened, and the metal foil becomes the glass surface. It is a technical problem that it is easy to peel off.

  In order to further improve the external electrode discharge lamp shown in FIG. 10, it is conceivable to apply a metal foil as an electrode to the outer periphery of the glass lamp vessel with a conductive adhesive. However, when the conductive adhesive for adhering the metal foil to the glass surface is made by dispersing conductive particles such as iron particles in an acrylic adhesive, the external electrode discharge shown in FIG. As in the case of the lamp, when the lamp current is high or when the ambient temperature is high, the adhesive carbonizes, causing unevenness in the sheet resistance between the metal foil and the glass surface, resulting in a locally low resistance. However, there is a technical problem that the current concentrates and becomes high temperature, and a hole is generated in the glass container, or the adhesive strength of the adhesive is weakened and the metal foil is easily peeled off from the glass surface.

  The present invention has been made in view of such technical problems, and it is an object of the present invention to provide an external electrode discharge lamp that can increase the amount of light emission and achieve a long life.

  The present invention relates to an external electrode discharge lamp in which electrodes are formed on the outer peripheral portions of both ends in the axial direction of a tubular glass lamp vessel in which a discharge medium is enclosed, and the electrode is attached to the outer periphery of the glass lamp vessel by an adhesive. It is characterized by comprising a plastic conductor layer adhered and a contact metal conductor attached to the outer periphery of the conductor layer.

  In the present invention, the pressure-sensitive adhesive layer is one or more selected from silicon resin, fluororesin, polyimide resin, and epoxy resin, in which conductive particles are dispersed. Can be.

  In the present invention, the conductive particles in the pressure-sensitive adhesive may be one or more selected from iron, nickel, silver, and carbon.

  Furthermore, in the present invention, the conductor layer of the electrode may be at least one of tin foil, aluminum foil, or copper foil.

  According to the present invention, the electrical contact between the contact metal conductor and the outer peripheral surface of the glass lamp container is good, and the substantial electrode area is the electrode area when the contact metal conductor alone is fitted to the glass lamp container. The efficiency can be improved as a result.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a cross-sectional structure of an external electrode discharge lamp 12 according to a first embodiment of the present invention. In the external electrode discharge lamp 12 of the present embodiment, a filler 50 capable of ionization such as a rare gas or a mixed gas of mercury and a rare gas is sealed inside a tubular glass lamp vessel 20 sealed at both ends. Further, a phosphor layer 60 is formed on the inner peripheral surface of the glass lamp vessel 20 as necessary, and foil-like metal conductors 31 and 41 as electrodes 70 and 80 are formed on the outer circumferences of both ends of the glass lamp vessel 20 with the following composition. In this structure, the conductive adhesives 32 and 42 are attached.

  For the metal conductors 31 and 41 constituting the electrodes 70 and 80, for example, tin foil, aluminum foil or copper foil having plasticity is used. For the conductive adhesives 32 and 42, for example, conductive resin such as iron particles, nickel particles, silver particles or carbon particles is added to a silicone resin, fluorine resin or polyimide resin adhesive having a high heat resistance temperature. Use a dispersed one. Furthermore, an epoxy resin system can also be used for the adhesive.

  Low cost and highly reliable conductivity can be obtained by selecting iron particles or nickel particles as conductive particles to be mixed in the adhesive, and highly reliable conductivity can be obtained by low resistance by selecting silver particles. If carbon particles are selected, the conductivity can be obtained at a lower cost.

  The discharge lamp 12 is manufactured by winding a metal tape having a conductive adhesive having the above composition applied on the back surface around both ends of the glass lamp container 20.

  As described above, according to the external electrode discharge lamp of the present embodiment, it is easy to form an electrode, and the deterioration of the adhesive that occurs during the operation of the lamp even when the lamp current is high and the ambient temperature is high. It is possible to suppress the occurrence of non-uniformity in the resistance value of the pressure-sensitive adhesive layer, prevent the occurrence of perforation in the electrode part of the glass container, and also prevent the metal foil of the electrode from peeling off from the glass container. It is possible to stably emit light with a high light amount.

  Next, an external electrode discharge lamp according to a second embodiment of the present invention will be described with reference to FIGS. The second embodiment is an external electrode discharge lamp 13 that uses abutting metal conductors 90 and 100 as fixtures and electrodes. In the external electrode discharge lamp 13 of this embodiment, since the contact metal conductors 90 and 100 are the electrodes 70 and 80, adhesion with the glass lamp container 20 is required.

  However, even if the abutting metal conductors 90 and 100 are directly attached to the outer periphery of the end portion of the glass lamp container 20, since they are rigid bodies, their adhesion to the outer peripheral surface of the glass lamp container 20 is poor, and therefore It is difficult to realize the indicated electrode area S as designed.

  Therefore, in the external electrode discharge lamp 13 of the present embodiment, the outer periphery of both ends of the glass lamp container 20 is increased in order to improve the adhesion between the inner periphery of the contact metal conductors 90 and 100 and the outer peripheral surface of the glass lamp container 20. A plastic conductive material such as metal tapes 35 and 45 coated with adhesives 34 and 44 is wound around the back surface, and contact metal conductors 90 and 100 are fitted around the outer periphery of the metal tapes 35 and 45.

  As a result, the abutting metal conductors 90 and 100 and the plastic inner metal tapes 35 and 45 are in close contact with each other, and the metal tapes 35 and 45 are in close contact with the outer peripheral surface of the glass lamp container 20. The electrical contact between the metal contact conductors 90 and 100 and the outer peripheral surface of the glass lamp container 20 is improved, and the substantial electrode area S is the electrode area when the contact metal conductor alone is fitted to the glass lamp container 20. Is much improved.

  In addition, a silver paste can also be employ | adopted for a plastic conductive material. Further, as the adhesive on the back surface of the metal tapes 35 and 45, the same resin adhesive as that of the first embodiment is used, and the conductive adhesive in which metal particles are dispersed is used, thereby further improving the lamp performance. Can be improved.

  Next, an external electrode discharge lamp 14 according to a third embodiment of the present invention will be described with reference to FIG. The present embodiment is characterized in that the electrodes 70 and 80 are configured by sticking the metal mesh cloths 36 and 46 to the outer peripheral portions of both ends of the tubular glass lamp vessel 20 with adhesives 37 and 47. Other configurations are the same as those of the first embodiment shown in FIG. 1, and the same reference numerals denote the same elements.

  In the case of this embodiment, when the metal mesh cloths 36, 46 are pressed against the surface of the tubular glass lamp container 20, the fibers of the metal mesh cloths 36, 46 come into contact with the glass surface via a very thin adhesive layer. Thus, the occurrence of uneven resistance distribution between the metal mesh cloths 36 and 46 and the surface of the glass lamp vessel 20 can be suppressed, and the current density is locally increased to open a hole in the glass lamp tube. Can be prevented. Further, since there are many gaps in the thickness direction in the metal mesh cloths 36 and 46, the metal mesh cloths 36 and 46 are strongly pressed against the surface of the tubular glass lamp container 20 to be attached, whereby the layers of the adhesives 37 and 47 are formed. And air bubbles between the surface of the tubular glass lamp vessel 20 can be eliminated.

  In this embodiment, the material of the metal mesh cloths 36 and 46 can be selected from at least one of nickel, iron, copper, aluminum, and tin, thereby forming an inexpensive and highly reliable external electrode. Can do.

  Further, by using an epoxy, silicon, fluorine, or polyimide resin having high heat resistance as the adhesives 37 and 47, uneven resistance value distribution between the metal mesh cloths 36 and 46 and the surface of the glass lamp vessel 20 is achieved. Can be further eliminated.

  Next, an external electrode discharge lamp 15 according to a fourth embodiment of the present invention will be described with reference to FIG. The feature of this embodiment is that metal mesh cloths 36 and 46 are attached to the outer peripheral portions of both ends of the tubular glass lamp container 20 using conductive adhesives 38 and 48 in which conductive particles are dispersed in an adhesive layer. It is characterized by. Other configurations are the same as those of the first embodiment shown in FIG. 1, and the same reference numerals denote the same elements.

  Also in this embodiment, the material of the metal mesh cloths 36 and 46 can be selected from at least one of nickel, iron, copper, aluminum, and tin, thereby forming an inexpensive and highly reliable external electrode. be able to.

  In addition, one or a plurality of conductive particles selected from iron, nickel, silver and carbon in an epoxy, silicon, fluorine or polyimide adhesive having high heat resistance as the conductive adhesives 38 and 48 Can be used, whereby the occurrence of uneven resistance value distribution between the metal mesh cloths 36 and 46 and the surface of the glass lamp vessel 20 can be further eliminated.

  Next, an external electrode discharge lamp 16 according to a fifth embodiment of the present invention will be described with reference to FIG. The present embodiment is characterized in that the electrodes 70 and 80 are configured by sticking embossed metal foils 39 and 49 to the outer peripheral portions of both ends of the tubular glass lamp vessel 20 with adhesives 37 and 47, respectively. Other configurations are the same as those of the first embodiment shown in FIG. 1, and the same reference numerals denote the same elements.

  The embossed metal foils 39 and 49 are in contact with the surface of the tubular glass lamp vessel 20 through a very thin adhesive layer at the convex portions on the inside, and the adhesive 37 on the back side of the convex portions on the outside. , 47 are formed, and the embossed metal foils 39, 49 are fixed to the surface of the glass lamp vessel 20.

  As the pressure-sensitive adhesives 37 and 47, epoxy, silicon, fluorine, or polyimide with high heat resistance can be used.

  In the case of this embodiment, since the adhesive layer between the embossed metal foils 39 and 49 and the surface of the glass lamp container 20 is made extremely thin, the metal foil between the glass and the glass due to the deterioration of the adhesive during lamp operation. Occurrence of unevenness of the resistance value distribution can be suppressed, and it is possible to prevent the current density from locally increasing and opening a hole in the glass.

  Next, an external electrode discharge lamp 17 according to a sixth embodiment of the present invention will be described with reference to FIG. In this embodiment, the embossed metal foils 39 and 49 are bonded to the outer peripheral portions of the both ends of the tubular glass lamp container 20 by the conductive adhesives 38 and 48 in which the conductive particles are dispersed. It is characterized by comprising. Other configurations are the same as those of the first embodiment shown in FIG. 1, and the same reference numerals denote the same elements.

  Also in the external electrode discharge lamp 17 of the present embodiment, as in the case of the external electrode discharge lamp 16 of the fifth embodiment, the convex portions inside the embossed metal foils 39 and 49 are the glass lamp container 20. A layer of conductive adhesives 38 and 48 is formed on the back side of the convex portion on the outside, and the embossed metal foils 39 and 49 are fixed to the glass surface. ing.

  The conductive adhesives 38 and 48 include one or more conductive particles selected from iron, nickel, silver, and carbon in an epoxy, silicon, fluorine, or polyimide adhesive with high heat resistance. Can be used by dispersing and mixing.

  In the external electrode discharge lamp 17 of the present embodiment, the adhesive layer is also made conductive, so that the adhesive is deteriorated in the portion between the convex portions on the inside of the embossed metal foils 39 and 49 and the glass surface. The change in the resistance value of the pressure-sensitive adhesive layer due to can be further reduced, and the occurrence of uneven resistance value distribution between the metal foil and the glass can be more reliably eliminated.

  An external electrode discharge lamp of an example corresponding to this embodiment and an external electrode discharge lamp of a comparative example will be described.

Example 1
<Tubular glass lamp vessel> Material: Borosilicate glass, Dimensions: 2.6 mm outer diameter, 2.0 mm inner diameter, 350 mm in total length.

  <Metal foil of electrode> Aluminum foil, dimensions: thickness 0.1 mm, electrode length 20 mm.

  <Electroconductive adhesive for electrode> Material: Iron particles are dispersed in a silicone resin adhesive.

  <Phosphor layer> Material: three-wavelength phosphor, layer thickness: 20 μm.

  <Filler> (1) Filling gas: mixed gas of neon and argon (composition ratio: neon / argon = 90 mol% / 10 mol%), sealing pressure: 60 Torr. (2) Mercury: enclosed amount 3 mg.

(Comparative Example 1)
Except for the composition of the pressure-sensitive adhesive of the electrode, it is common with Example 1. An acrylic adhesive was used as the electrode adhesive. Conductive particles are not dispersed in the adhesive.

  A lighting test was performed on the external electrode discharge lamp having the specifications of Example 1 and Comparative Example 1 with a lamp current of 6 mA. As a result of this lighting test, in the case of Comparative Example 1, a hole was generated in the glass container in about 70 to 1000 hours, whereas in the case of Example 1, the hole was formed in the glass container even after continuous lighting for 5000 hours. Did not occur.

(Example 2)
<Tubular glass lamp vessel> Material: Borosilicate glass, Dimensions: 2.6 mm outer diameter, 2.0 mm inner diameter, 350 mm in total length.

  <Abutting metal conductor> Material: stainless steel mesh, dimensions: thickness 0.2 mm, electrode length: 20 mm.

  <Metal tape> Aluminum foil coated with acrylic resin adhesive, dimensions: thickness 0.1 mm, electrode length 20 mm.

  <Phosphor layer> Material: three-wavelength phosphor, layer thickness: 20 μm.

  <Filler> (1) Filling gas: mixed gas of neon and argon (composition ratio: neon / argon = 90 mol% / 10 mol%), sealing pressure: 60 Torr. (2) Mercury: enclosed amount 3 mg.

(Comparative Example 2)
A contact metal conductor was attached to both ends of the glass lamp vessel common to Example 2 without using a metal tape.

  When a high frequency voltage of 3500 V and 50 kHz was supplied between the electrodes for the external electrode discharge lamps of the specifications of Example 2 and Comparative Example 2 above, a current of about 6 mA flowed in Comparative Example 2. In the case of Example 2, a current of 8 mA could be passed.

  Thus, in the external electrode discharge lamp of Example 2, the adhesion between the glass lamp vessel surface and the abutting metal conductor is better than when the abutting metal conductor is directly attached to the glass lamp vessel, and the applied voltage is the same. In this case, the light emission amount can be increased, and when the light emission amount is the same, the power consumption can be reduced.

(Example 3)
<Tubular glass lamp vessel> Material: Borosilicate glass. Dimensions: 2.6 mm outer diameter, 2.0 mm inner diameter, total length 379 mm.

  <External electrode> Nickel mesh cloth + conductive silicone adhesive layer. External electrode length: 17 mm.

  <Phosphor layer> Material: Three-wavelength phosphor. Thickness: 20 μm.

  <Filler> Filled gas: A mixed gas of neon and argon (composition ratio: neon / argon = 90 mol% / 10 mol%). Sealing pressure: 8 kPa. Mercury: 3 mg enclosed.

Example 4
<Tubular glass lamp vessel> Material: Borosilicate glass. Dimensions: 2.6 mm outer diameter, 2.0 mm inner diameter, total length 379 mm.

  <External electrode> Embossed aluminum foil + conductive silicone adhesive layer. External electrode length: 17 mm.

  <Phosphor layer> Material: Three-wavelength phosphor. Thickness: 20 μm.

  <Filler> Filled gas: A mixed gas of neon and argon (composition ratio: neon / argon = 90 mol% / 10 mol%). Sealing pressure: 8 kPa. Mercury: 3 mg enclosed.

(Comparative Example 3)
<Tubular glass lamp vessel> Material: Borosilicate glass. Dimensions: 2.6 mm outer diameter, 2.0 mm inner diameter, total length 379 mm.

  <External electrode> Aluminum foil + acrylic adhesive layer. External electrode length: 17 mm.

  <Phosphor layer> Material: Three-wavelength phosphor. Thickness: 20 μm.

  <Filler> Filled gas: A mixed gas of neon and argon (composition ratio: neon / argon = 90 mol% / 10 mol%). Sealing pressure: 8 kPa. Mercury: 3 mg enclosed.

  When the discharge lamp of each of Example 3 and Example 4 and the discharge lamp of Comparative Example 3 were lit for 5000 hours at a lamp current of 5 mA, in Comparative Example 3, a hole was formed in the glass in about 70 to 1000 hours. In each of the discharge lamps of Example 3 and Example 4, no holes were formed in the glass even when the lamps were lit for 5000 hours.

  In the case of the discharge lamps of Example 3 and Example 4, this suppresses a change in the resistance value between the metal mesh cloth or embossed metal foil of the external electrode and the tubular glass lamp vessel, which occurs during lamp lighting, By preventing the occurrence of unevenness in the value distribution, it is considered that the glass could be prevented from opening a hole.

1 is an axial sectional view of an external electrode discharge lamp according to a first embodiment of the present invention. Sectional drawing of the axial direction of the external electrode discharge lamp of the 2nd Embodiment of this invention. Sectional drawing of the direction perpendicular | vertical to the axis | shaft of the external electrode discharge lamp of the said 2nd Embodiment. Sectional drawing of the axial direction of the external electrode discharge lamp of the 3rd Embodiment of this invention. Sectional drawing of the axial direction of the external electrode discharge lamp of the 4th Embodiment of this invention. Sectional drawing of the axial direction of the external electrode discharge lamp of the 5th Embodiment of this invention. Sectional drawing of the axial direction of the external electrode discharge lamp of the 6th Embodiment of this invention. Sectional drawing of the axial direction of the external electrode discharge lamp of a prior art example. Equivalent circuit of external electrode discharge lamp. Sectional drawing of the axial direction of the external electrode discharge lamp of a comparative example.

Explanation of symbols

12-17 Discharge lamp 20 Glass lamp vessel 31 Metal conductor 32 Conductive adhesive 34 Adhesive 35 Metal tape 36 Metal mesh cloth 37 Adhesive 38 Conductive adhesive 39 Embossed metal foil 41 Metal conductor 42 Conductive adhesive 44 Adhesive 45 Metal tape 46 Metal mesh cloth 47 Adhesive 48 Conductive adhesive 49 Embossed metal foil 50 Filler 60 Phosphor layer 70, 80 Electrode 90 Abutting metal conductor 100 Abutting metal conductor

Claims (1)

  An external electrode discharge lamp in which electrodes are formed on the outer peripheral portions of both ends in the axial direction of a tubular glass lamp container in which a discharge medium is enclosed. The electrode is adhered to the outer periphery of the glass lamp container with an adhesive. An external electrode discharge lamp comprising a conductive layer having plasticity and an abutting metal conductor attached to the outer periphery of the conductive layer.

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