JP2008021584A - Planal fluorescent lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planar fluorescent lamp capable of preventing breakage of a joint member. <P>SOLUTION: This planar fluorescent lamp includes: a discharge vessel 1 having a first joint member 21 formed therein to set the insides of a front glass substrate 1a and a back glass substrate 1b facing to each other airtight; a discharge medium filled in the discharge vessel 1; and external electrodes 5a and 5b formed on the discharge vessel 1. The external electrodes 5a and 5b are formed on the outside surface of the discharge vessel 1 so as not to generate an electric field on the first joint member 21. Specifically, the external electrodes 5a and 5b are each formed into an electrode structure without being formed on a surface of the front glass substrate 1a corresponding to a part of the discharge vessel 1 with the first joint member 21 formed thereon. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a flat fluorescent lamp used for a backlight of a liquid crystal display or general illumination.

  As a flat type fluorescent lamp, there is JP-A-2005-340199 (hereinafter referred to as Patent Document 1). This type of flat fluorescent lamp is composed of a flat discharge vessel. This discharge vessel is formed by forming a bonding member made of frit glass or the like on the edges of two glass substrates and bonding them together, and a discharge medium made of rare gas or mercury is enclosed inside. ing. In addition, a pair of external electrodes are formed outside the discharge vessel. When voltage is applied to the external electrodes, plasma is generated inside the discharge vessel and surface emission occurs.

  As a method for exhausting and introducing gas in such a flat fluorescent lamp, a method is generally employed in which an exhaust pipe is formed in a discharge vessel, and the inside of the lamp is exhausted and introduced through the exhaust pipe. . One example is JP-A-2005-26041 (hereinafter referred to as Patent Document 2). As in Patent Document 2, the exhaust pipe is often joined to the discharge vessel by a joining member such as frit glass.

  This exhaust pipe is chipped off by a burner or the like after exhausting inside the discharge vessel and introducing gas, and remains on the surface of the vessel as an exhaust tip as disclosed in JP-A-2006-93072 (hereinafter, Patent Document 3). It will be.

Japanese Patent Laying-Open No. 2005-340199 (FIGS. 1 and 2) Japanese Patent Laying-Open No. 2001-283741 (FIG. 1) JP 2006-93072 A (FIGS. 1 and 4)

  However, in the flat fluorescent lamp as described above, there is a problem that a pinhole is generated in the bonding member formed on the glass substrate during lighting, a crack is generated and the bonding member is melted. As a result, airtightness inside the discharge vessel cannot be maintained, and lighting may not be performed.

  Similar problems may occur when the exhaust pipe is joined to the flat fluorescent lamp by a joining member as in Patent Document 2 and Patent Document 3.

  The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a flat fluorescent lamp capable of preventing the joining member from being damaged.

  In order to achieve the above object, a flat fluorescent lamp of the present invention is enclosed in a discharge vessel in which a first joining member is formed so as to make the inside of an opposing glass substrate airtight, and the inside of the discharge vessel. A discharge medium and at least one external electrode formed on the discharge vessel, wherein the external electrode is formed on an outer surface of the discharge vessel so that an electric field is not generated in the first bonding member. It is characterized by being.

  According to the present invention, it is possible to prevent the joining member from being damaged.

  Hereinafter, a flat fluorescent lamp according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an overall view of a flat fluorescent lamp according to a first embodiment of the present invention on the front side, and FIG. 2 is an overall view of FIG. 1 viewed from the back side. 3 is a view of a cross section taken along the line X-X ′ in FIG. 1 as viewed from the direction of the arrow, and FIG. 4 is a view of the cross section taken along the line Y-Y ′ in FIG.

  The discharge vessel 1 constituting the main part of the flat fluorescent lamp is composed of a front glass substrate 1a and a rear glass substrate 1b made of translucent glass, for example, soda glass. Bonding of these glass substrates is performed by forming and bonding together a first bonding member 21 made of, for example, frit glass at the edges of the front glass substrate 1a and the back glass substrate 1b.

  Front glass substrate 1a has a plate shape and is a substrate that serves as a light emitting surface in the present embodiment. A hole 1a1 for exhaust and gas introduction is formed at the end of the front glass substrate 1a. Further, an exhaust chip 3 is formed in the hole 1a1 so as to surround the hole, and protrudes toward the light emitting surface. The exhaust tip 3 is originally cylindrical, but is formed by shrinking a part with a burner or the like after the exhaust / gas is introduced into the discharge vessel 1 and turning off the tip. The exhaust tip 3 is joined to the discharge vessel 1 by forming a second joining member 22 made of, for example, frit glass at a contact portion between the exhaust tip 3 and the front glass substrate 1a.

The frit glass used for the first and second joining members has a relatively low melting point than the material used for the glass substrate, and the expansion coefficient is close to that of the front glass substrate 1a and the back glass substrate 1b. A material is desired. For example, BiO-based frit glass such as Bi ₂ O ₃ can be used for the soda glass used as the glass substrate in the present embodiment. The frit glass used as the second bonding member 22 may be the same as or different from the frit glass used as the first bonding member 21.

  The back glass substrate 1b is composed of a corrugated portion 1b1 and a sealing portion 1b2. Such a specially shaped substrate can be obtained, for example, by thermoforming a glass plate that is originally a flat plate. The corrugated portion 1b1 has a corrugated shape, and has a shape in which a plurality of crest portions are alternately arranged on the front side of the discharge vessel 1 and a plurality of trough portions are alternately arranged on the back side. Therefore, in a state where the front glass substrate 1a is disposed on the rear glass substrate 1b, the waved portion 1b1 has a function of dividing the discharge space inside the discharge vessel 1 into a plurality of discharge cells 1c and supporting the front glass substrate 1a. That is, the waved portion 1b1 may have a shape such as a square shape, a semi-elliptical shape, and a trapezoidal shape having the same type of function. The sealing part 1b2 is a part that forms the outer edge of the rear glass substrate 1b. The inside of the discharge vessel 1 can be kept airtight by forming the first bonding member 21 in this portion, bonding the front glass substrate 1a, and heat-sealing.

  A discharge medium containing mercury and a rare gas is sealed inside the discharge vessel 1. The rare gas can be sealed as at least one gas selected from xenon, krypton, argon, neon, and helium, or a mixed gas of two or more. In addition, when two or more kinds of rare gases are mixed and sealed, it is desirable to seal in consideration of characteristics peculiar to the rare gas. For example, in the case of a mixed gas composed of neon and argon, if neon: argon = 50: 50 to 99: 1, the luminous efficiency and the low voltage startability characteristics of the lamp can be improved, and neon: argon = 1. If it is set to 99:50:50, the rising characteristic of light emission can be improved. The gas pressure should be 1 to 700 torr, preferably 20 to 100 torr, taking into consideration the characteristics of luminous efficiency, low voltage startability, and life.

  Phosphor layers 4a and 4b are formed on the inner surface of the discharge vessel 1, that is, the discharge space side surfaces of the front glass substrate 1a and the rear glass substrate 1b. The phosphor layers 4a and 4b only need to convert ultraviolet rays radiated from mercury by discharge into visible light. For example, the phosphor layers 4a and 4b may be a single color phosphor or a plurality of RGB used in general illumination or cold cathode fluorescent lamps. Species phosphors can be used. It is also possible to apply phosphors of different emission colors in a striped pattern or a dot pattern.

  Here, in the present embodiment, the front glass substrate 1a side is the light exit surface, and the rear glass substrate 1b side is the reflection surface, so that the front side increases the light transmission efficiency and the back side increases the light reflection efficiency. It is desirable to do. For example, the phosphor layer 4a has an average particle diameter of about 2.5 μm or more and a thickness of 5 to 15 μm, and the phosphor layer 4b has an average particle diameter of about 2.5 μm or less and a thickness of 30 to 200 μm. Good. In order to further improve the reflection efficiency on the back side, a fine metal oxide layer made of titanium oxide, aluminum oxide, yttrium oxide or the like is preferably formed between the back glass substrate 1b and the phosphor layer 4b. Further, a protective layer of aluminum oxide or yttrium oxide may be formed between the phosphor layers 4a and 4b in order to prevent mercury from moving to the surface of the front glass substrate 1a and the back glass substrate 1b.

  In this embodiment, the phosphor layers are formed on both surfaces of the front glass substrate 1a and the back glass substrate 1b. However, the present invention is not necessarily limited to this configuration. For example, the phosphor layer on the back glass substrate 1b side is omitted. Also good. Further, a part of the phosphor layer may be removed from some parts of the discharge vessel 1. For example, the phosphor layer at the contact portion between the front glass substrate 1a and the corrugated portion 1b1 is removed, the phosphor layer on the inner surface of the container where the external electrodes 5a and 5b are formed, or the exhaust chip 3 is formed. The phosphor layer near the inner surface of the container may be removed.

  A pair of strip-like external electrodes 5a and 5b to which a high voltage and a low voltage are applied are formed at both ends of the outer surface of the front glass substrate 1a in a direction crossing the waved portion 1b1. The external electrodes 5a and 5b are made of a solder containing at least one kind of tin, indium, bismuth, lead, zinc, antimony, and silver by a dispenser or dipping while applying ultrasonic vibration. There is no limitation on the formation of the external electrodes 5a and 5b, and a conductive paste formed by adhering a conductive tape such as aluminum with a conductive adhesive or mixing a metal powder such as silver, a solvent and a binder is screened. The electrode may be formed by printing.

  Here, the formation place on the glass surface of the discharge vessel 1 of the external electrodes 5a and 5b will be described in detail. FIG. 5 is a top view of a flat fluorescent lamp for explaining a place where an external electrode is formed. In addition, the dotted line in a figure shows the formation range of the 1st joining member.

  As can be seen, the external electrodes 5a and 5b are not formed on the surface of the front glass substrate 1a corresponding to the portion of the discharge vessel 1 on which the first bonding member 21 is formed. In other words, the external electrodes 5 a and 5 b exist only within a range surrounded by the first bonding member 21. Specifically, the first bonding member 22 and the external electrodes 5a and 5b are separated from each other without overlapping, that is, the distance L from the first bonding member 21 to the external electrodes 5a and 5b is L ≧ 0 mm. That is, when a voltage is applied to the external electrodes 5a and 5b during lighting and the lamp is subjected to dielectric barrier discharge, an electric field is not easily generated in the first bonding member 21.

  The exhaust chip 3 is formed on the surface of the front glass substrate 1a outside the space between the external electrodes 5a and 5b. Here, “the exhaust tip is formed on the glass substrate surface outside the external electrode” means that the exhaust tip 3 does not exist between the external electrodes or in the external electrode. Further, the second bonding member 22 and the external electrodes 5a and 5b are at least non-contact, that is, the distance L ′ from the second bonding member 22 to the external electrodes 5a and 5b is in a state where L ′> 0 mm. That is, when a voltage is applied to the external electrodes 5a and 5b, the voltage is not positively applied to the exhaust tip 3 and the second bonding member 22.

  FIG. 6 is a view showing one specification such as dimensions and materials of the flat fluorescent lamp of the present invention. The following tests are based on this specification unless otherwise specified.

Discharge vessel 1: made of soda glass, 730 mm × 405 mm × 4.4 mm, width W of each discharge space: 6.0 mm, height H: 2.4 mm,
Discharge medium Mercury: 100 mg, neon: argon = 9: 1, 60 torr,
Phosphor layer 4a Particle size: 5.0 μm, layer thickness: 150 μm,
Phosphor layer 4b particle size: 2.4 μm, layer thickness: 10 μm,
External electrodes 5a, 5b Length: 395mm, Width: 20mm
Distance L from first bonding member 21 to external electrodes 5a and 5b: 0.5 mm
Distance L ′ from second joining member 22 to external electrodes 5a and 5b: 0.5 mm
FIG. 7 is a diagram illustrating the presence or absence of breakage in the first bonding member when the distance L from the first bonding member to the external electrode is changed. This test result is when 2000 Vrms is applied between the electrodes for 10,000 hours, and the number of tests is 20 for each.

  From the results, it can be seen that as the distance L from the first bonding member 21 to the external electrodes 5a and 5b becomes longer in the positive direction, the first bonding member 21 is less likely to be damaged. Specifically, when L is negative (when the external electrodes 5a and 5b are overlapped on the first bonding member 21), the occurrence rate of damage is high, but L = 0 mm (the first bonding member 21 and the external member). In a state where the electrodes 5a and 5b are in contact with each other, the occurrence rate of breakage is low, and when L ≧ 0.5 mm, breakage does not occur.

  The reason why the first bonding member 21 is damaged due to the distance L between the external electrodes 5a and 5b and the first bonding member 21 is that an electric field is generated in the frit glass (first bonding member 21). This is because when an electric field is generated in the frit glass, the ionized discharge medium collides with the frit glass and generates heat. When the temperature of the frit glass rises to some extent due to the heat generation, the frit glass has a lower melting point than the soda glass constituting the glass substrate as described above, and thus it is considered that pinholes are generated and broken.

  In addition, when air bubbles are generated inside the frit glass, breakage is more likely to occur. The bubbles are bubbles generated in the frit glass as shown in FIG. 8, and are generated before and after the joining process of the front glass substrate 1a and the back glass substrate 1b.

  A thickener is usually added to the frit glass used for joining the front glass substrate 1a and the back glass substrate 1b. This thickener is added to form a paste at the time of application, but is thermally decomposed when the front glass substrate 1a and the back glass substrate 1b are joined. During the thermal decomposition, bubbles are generated inside the frit glass. Gases such as nitrogen, oxygen and carbon dioxide are sealed inside the bubbles. Therefore, when an electric field is generated in the frit glass and a voltage is applied to the frit glass part containing bubbles, the gas trapped inside the bubbles is discharged, and the frit glass is melted or cracked by the impact of this discharge. May occur and be damaged.

  As described above, in order to prevent an electric field from being generated in the first bonding member 21, it is preferable to adopt a configuration in which the external electrodes 5a and 5b are not formed in the portion where the first bonding member 21 is formed. all right. From experimental results, it is more desirable that L ≧ 0.5 mm. However, if L is too long, the light emitting surface becomes small, so it is desirable that L ≦ 5.0 mm.

  Note that the result of FIG. 7 varies somewhat depending on the value of the applied voltage. That is, even when the distance L from the first bonding member 21 to the external electrodes 5a and 5b is the same, when the applied voltage is small, a strong electric field is hardly formed in the first bonding member 21, and the input power and the applied voltage are large. In this case, a strong electric field is easily formed on the first bonding member 21. Therefore, in the case of a large flat fluorescent lamp in which the applied voltage is large, a configuration in which a distance L from the first joining member 21 to the external electrodes 5a and 5b is secured longer than usual is adopted. Is desirable.

  In addition, when the exhaust tip 3 is formed in the discharge vessel 1, the frit glass may be broken by the same mechanism in the second joining member 22 that joins the exhaust tip 3. The joining member 21 is preferably not in contact with the external electrodes 5a and 5b (L ′> 0 mm), and the exhaust tip 3 is preferably formed on the surface of the front glass substrate 1a outside the external electrodes 5a and 5b. A more preferable range of L ′ is L ′ ≧ 0.5 mm.

  Therefore, in the present embodiment, the external electrodes 5a and 5b are not formed on the surface of the front glass substrate 1a corresponding to the portion of the discharge vessel 1 on which the first bonding member 21 is formed, that is, the first bonding. Since the distance L from the member 21 to the external electrodes 5a and 5b is L ≧ 0 mm, it is possible to prevent an electric field from being generated in the first bonding member 21, and thus the first bonding member due to the occurrence of a pinhole or the like 21 can be prevented from being damaged. If L ≧ 0.5 mm, a further higher effect can be obtained.

  When the exhaust tip 3 is formed in the discharge vessel 1, the second bonding member 21 is not in contact with the external electrodes 5a and 5b, that is, the distance L ′ from the second bonding member 22 to the external electrodes 5a and 5b. Since L ′> 0 mm and the exhaust chip 3 is formed on the surface of the front glass substrate 1a outside the external electrodes 5a and 5b, it is possible to prevent an electric field from being generated in the second bonding member 22. The breakage of the two joining members 22 can be prevented.

  Further, when the first and / or second joining members 21 and 22 contain bubbles, cracks caused by the discharge of the gas enclosed in the bubbles can be achieved by adopting the present invention. Can be prevented from being damaged.

  The embodiment of the present invention is not limited to the above, and may be modified as follows, for example.

  The electrode configuration is not limited to the case where the external electrodes 5a and 5b are formed on the front side as in the first embodiment, and the electrode configuration is formed on the back side or on both the front side and the back side. You may do it. Moreover, the structure which one is an external electrode and the other is an internal electrode may be sufficient. That is, the electrode configuration is not limited as long as the lamp configuration includes at least one external electrode and dielectric barrier discharge.

1 is an overall front view of a flat fluorescent lamp according to a first embodiment of the present invention. The whole figure which looked at Drawing 1 from the back side. The figure which looked at the cross section of X-X 'in FIG. 1 from the arrow direction. The figure which looked at the cross section of Y-Y 'in FIG. 1 from the arrow direction. The top view of the flat type fluorescent lamp for demonstrating the formation place of an external electrode. The figure which shows one specification of the dimension, material, etc. of the flat fluorescent lamp of this invention. The figure explaining the presence or absence of generation | occurrence | production of the damage in a 1st joining member when changing the distance L from a 1st joining member to an external electrode. The figure which shows the bubble which generate | occur | produced in the frit glass.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge container 1a Front glass substrate 1a1 Hole 1b Back glass substrate 1b1 Wave-like part 1b2 Sealing part 1c Discharge cell 21, 22 First, 2nd joining member 3 Exhaust chip 4a, 4b Phosphor layer 5a, 5b External electrode

Claims (5)

A discharge vessel in which a first bonding member is formed so as to make the inside of the opposing glass substrate airtight, a discharge medium sealed in the inside of the discharge vessel, and at least one external electrode formed in the discharge vessel And
The flat fluorescent lamp, wherein the external electrode is formed on an outer surface of the discharge vessel so that an electric field is not generated in the first bonding member. A discharge vessel in which a first bonding member is formed so as to make the inside of the opposing glass substrate airtight, a discharge medium sealed in the inside of the discharge vessel, and at least one external electrode formed in the discharge vessel And
The flat fluorescent lamp according to claim 1, wherein the external electrode is not formed on the glass substrate surface corresponding to the discharge vessel portion on which the first bonding member is formed.   3. The flat fluorescent lamp according to claim 2, wherein L ≧ 0.5 mm, where L is a distance from the first joining member to the external electrode.   The discharge vessel includes an exhaust tip joined to the outer surface thereof by a second joining member, the second joining member is not in contact with the external electrode, and the exhaust tip is outside the external electrode. The flat fluorescent lamp according to claim 1, wherein the flat fluorescent lamp is formed on a surface of the glass substrate. 5. The flat fluorescent lamp according to claim 1, wherein the first and / or the second joining member includes air bubbles therein. 6.

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