KR101206681B1 - Cold cathode fluorescent lamp of high efficiency and long life for illumination - Google Patents

Abstract

PURPOSE: A cold cathode fluorescent lamp is provided to have high luminance radiation by forming an alloy with a double coil structure. CONSTITUTION: A base metal is combined with the front end of a lead wire(9a,9b). The helical basal body wire(3) is wound and formed in a helical structure. Coating coil emitters(21) are implanted in the helical basal body wire. Both ends of the wire compose the helical basal body wire and are drawn out toward the base metal(7). The wire drawn from the front end of helical basal body wire is drawn out to pass through inside of the helical basal body wire.

Description

COLD CATHODE FLUORESCENT LAMP OF HIGH EFFICIENCY AND LONG LIFE FOR ILLUMINATION}

The present invention relates to a cold cathode fluorescent lamp that can be used for lighting, and more particularly, the tube current of a cold cathode fluorescent lamp that has been used only as a backlight of a conventional LCD display, a read light source such as a facsimile, an erasure of a copier, etc. The present invention relates to a high efficiency long life Cold Cathode Fluorescent Lamp (HCL) for lighting that improves current, light efficiency, brightness and lifespan and enables it to be used as lighting.

Conventional Cold Cathode Fluorescent Lamps (CCFLs) have been used as light sources for backlights of LCD displays, reading light sources such as facsimiles, and erasures of copiers, which obtain the required luminance even with a tube current of 4-5 mA. In the cold cathode fluorescent lamp used for this purpose, a cup-shaped electrode is provided at both ends of the glass tube, and a fluorescent layer is formed on the inner wall of the glass tube by a fluorescent material. In addition, traces of mercury other than rare gases such as neon, argon and xenon are enclosed in the glass tube. When a high voltage is applied to the cup-shaped electrode across the glass tube, a small number of electrons present in the glass tube ionize the enclosed rare gas, and when the ionized rare gas strikes the cup-shaped electrode, secondary electrons are emitted from the cup-shaped electrode (this is called glow discharge). When the emitted secondary electrons hit mercury, ultraviolet rays are emitted from the mercury, and when the ultraviolet rays emitted from the mercury are irradiated onto the fluorescent layer formed on the inner wall of the glass tube, the fluorescent material emits visible light. As described above, the tube current inside the glass tube is about 4-5 mA. However, in order to obtain illuminance that can be used for lighting in cold cathode fluorescent lamps, the tube current should be flowed over 10mA.

Conventionally, in order to secure electron emission, the electrode of a cold-cathode fluorescent lamp focused on widening an internal area by shape | molding in cup shape. In addition, nickel (Ni) was mainly used as an electrode material. This is because nickel has a relatively low melting point and good moldability and is easily formed into a cup shape. However, nickel or nickel alloys have a high work function and a large sputtering coefficient. Nickel alloy cup electrodes formed of niobium (Nb) or yttrium (Y) alloys are sometimes used to increase sputtering resistance.However, even when using nickel alloy electrodes, sputtering occurs severely when the tube current is increased to 10 mA, resulting in very short lifespan. Lose. Sputtering causes excessive heat generation at the electrode, significantly lowering luminous flux efficiency, and forming a sputtering film on the inner wall of the glass tube, making it difficult to obtain illuminance required for illumination. Therefore, the nickel or nickel alloy electrode is not suitable for a cold cathode fluorescent lamp having a tube current of 5 mA or more, and it is difficult to implement a cold cathode fluorescent lamp for lighting using a cup nickel electrode or a cup nickel alloy electrode.

In addition, in the past, the size of the electrode was excessively large as it was focused on widening the area of the electrode. If the size of the electrode is too large, the electrode occupies a large place in the glass tube, which reduces the amount of light poles and decreases the luminous flux efficiency, resulting in higher energy consumption. This is one of the reasons for making the cold cathode fluorescent lamp unsuitable for general lighting. It was.

The present invention has been made to solve the above-mentioned problems caused when using a cold cathode fluorescent lamp for general lighting, the first problem to be solved by the present invention is a cold cathode of tungsten or tungsten alloy having a low sputtering coefficient and work function It is to provide a cold cathode fluorescent lamp for illumination that can be easily formed in a cup shape while forming an electrode.

The second problem to be solved by the present invention is to provide a cold cathode fluorescent lamp for illumination that can produce a high brightness while minimizing the length of the electrode.

A third object of the present invention is to provide a cold cathode fluorescent lamp for lighting having a structure in which a 2-wire lead wire can be easily inserted and inserted into a general hot cathode fluorescent lamp socket.

The fourth task to be solved by the present invention is to provide a cold cathode fluorescent lamp for illumination that can extend the life of the electrode by minimizing the discharge sustain voltage.

The fifth problem to be solved by the present invention is to provide a cold cathode fluorescent lamp for illumination that is easy to emitter coating and holding.

The first and second objects of the present invention described above include: a base metal coupled to a tip of a lead wire for inputting a cold cathode electrode of a cold cathode fluorescent lamp for illumination; A wire helical riser formed by winding a tungsten or tungsten alloy wire in a helical structure along the shape of a cup and connecting the base metal to stand in the glass tube length direction; And an emitter coating coil inserted into the wire helical standing body and having an emitter applied to its surface to induce electron emission.

The third object of the present invention described above is solved by connecting two lead wires, but connecting two lead wires to electrically short the base metal.

The fourth object of the present invention described above is, after forming the emitter coating coil into a tungsten or tungsten alloy thin wire thinner than the wire helical standing body, cesium oxide, barium oxide, strontium calcium oxide, and oxide on the thin wire surface. It is solved by coating one or more emitters selected from yttrium or magnesium oxide.

The fifth object of the present invention described above is a thin wire formed by winding the emitter coated coil using a tungsten thin wire thinner than the wire helical standing body, and then winding the thin wire coil in a spiral shape. It is solved by forming a coil helical structure and coating one or more emitters selected from cesium oxide, barium oxide, calcium strontium oxide, yttrium oxide, or magnesium oxide on the surface of the thin wire coil.

According to the present invention having the above-described configuration, having a double coil structure of tungsten or tungsten alloy, it is possible to emit light of high luminance with a low work function while maintaining sputtering resistance even when the tube current is 10 mA or more, and the length of the electrode Emission can be minimized while minimizing the amount of electrons.By providing a base metal between the lead wire and the wire helical standing body, it is easy to form a 2-wire lead wire that can be inserted into a general hot cathode fluorescent lamp socket. The secondary electron emission can be made at a low voltage, thereby minimizing the discharge sustain voltage, thereby increasing the life of the electrode, and forming a thin wire coil using a tungsten thin wire in the inner coil, and then resetting the thin wire coil. Emitter is formed on the surface of helical structure of thin wire coil wound in spiral shape By coating, there is an effect that the emitter coating and holding is easy.

1 is a perspective view of an emitter coated coil according to the present invention.
2 is an exploded perspective view of the cold cathode electrode according to the present invention.
3 is a perspective view of the combined cold cathode electrode according to the present invention.
4 is a partially omitted perspective view showing a state in which the cold cathode electrode according to the present invention is inserted into a glass tube and sealed.
5 is a partial cut cross-sectional view of a cold cathode fluorescent lamp for illumination according to the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, as can be seen with reference to Figures 4 and 5, the present invention is a cold cathode electrode which emits a large amount of electrons at both ends of the glass tube formed on the inner wall of the fluorescent layer, with a low sputtering coefficient, low starting voltage and low discharge holding voltage By providing a cold cathode fluorescent lamp can be used for lighting. The cold cathode fluorescent lamp for illumination according to the present invention includes a glass tube 17 having a fluorescent layer formed by a fluorescent material on an inner wall thereof, and a pair of cold cathode electrodes 1 disposed opposite to each other on the glass tube 17. High voltages are alternately applied to the cold cathode electrodes 1 at both ends, and electrons are emitted from the electrodes. The feature of the present invention is that the cold cathode electrode 1 is improved to increase the sputtering resistance and induce a large amount of electron emission which can achieve the tube current (10 mA or more) required for illumination with a low discharge starting voltage and a discharge holding voltage. This makes it possible to use a cold cathode fluorescent lamp for illumination.

Referring to FIG. 1, the emitter coating coil, which is the biggest feature of the present invention, is described as follows.

As shown in FIG. 1, the emitter coating coil 21 according to the present invention not only has a structure that is easy to apply the emitter 5 in a powder state, but also retains the emitter 5 for a long time without leaving. It has a structure to do it. That is, the most preferred embodiment of the emitter coating coil 21 according to the present invention is a tungsten thin wire thinner than the wire helical standing body (symbol 3 of FIG. 2) provided outside the emitter coating coil, as shown in FIG. After forming the thin wire coil 19 using a diameter (0.02 mm to 0.05 mm is the most ideal), the thin wire coil 19 is again wound into a spiral shape, and the helical of the thin wire coil 19 is formed. ) It is formed into a structure. As the emitter, one or more selected from among cesium oxide, barium oxide, strontium oxide calcium, yttrium oxide, or magnesium oxide is used. In the present invention, the material having the lowest work function is made of an emitter to facilitate electron emission. The lower the work function, the easier it is to emit electrons, which means that it is easier to discharge. Carbon nanotubes can be used to facilitate the application of emitters. At this time, the carbon nanotubes are dispersed in an appropriate amount of water and isopropyl alcohol, and the dispersion is promoted with sodium dodecylbenzenesulfonate as a surfactant to be used as a coating agent. When the emitter coating coil 21 is configured in this way, the length of the entire wire rod of the emitter coating coil can be increased to enable electron emission of 10 mA or more at a low voltage in a narrow space, and a fine wire coil when applying the emitter ( It is very easy to apply the emitter (5) because the emitter is closely applied in the gap between the thinly stacked thin windings of 19), and there is no detachment of the emitter (5) applied for a long time after the emitter is applied. Is extended.

The emitter coated coil is formed by winding a fine thin wire of tungsten or tungsten alloy (diameter 0.02 mm to 0.05 mm is most ideal) that is thinner than the wire helical standing body without forming the thin wire coil 19 in advance. You may. The fine wire surface is also coated with one or more emitters selected from cesium oxide, barium oxide, strontium oxide, yttrium oxide, or magnesium oxide. However, when the emitter is coated in this way, it is more difficult to apply than when using the thin wire coil 19, and the emitter coating holding time may be shortened.

As can be seen with reference to Figs. 2 and 3, another feature of the present invention is that the wire rod helical riser 3 is provided. The wire helical standing body 3 is formed by winding a tungsten or tungsten alloy wire (0.2 mm to 0.5 mm in diameter is suitable) in a helical structure along the shape of the cup. The glass tube is connected to stand in the longitudinal direction. In the cold cathode electrode 1 according to the present invention, the base metal 7 is coupled to the ends of the lead wires 9a and 9b for introducing power. As the lead wires 9a and 9b, a dumet wire or a Kobar wire is used. The lead wires 9a and 9b run in a direction perpendicular to the base metal 7. The wire helical standing body 3 stands in the opposite direction to the lead wires 9a and 9b in the base metal 7. The base metal 7 has a special meaning because the present invention enables the use of two lead wires in a general fluorescent lamp socket. The base metal 7 firmly fixes the wire helical standing body at both ends to stand in the direction of the glass tube, and easily connects two lead wires (dumet wire or cobar wire) to the wire helical rising body 3. Let me connect Therefore, the base metal should be made of a material that can be welded to both the wire helical riser 3 and the lead wire (dumet wire or Kovar wire). The base metal 7 may be formed in a rod shape or a bead shape. When tungsten or a tungsten alloy is used as the material of the base metal 7, its melting point is high and it cannot be welded to the wire helical riser 3 formed of tungsten or tungsten alloy. Therefore, the material of the base metal 7 is preferably nickel or nickel alloy. The wire helical riser 3 is electrically connected to one surface of the base metal 7 by spot welding or the like. The lead wires 9a and 9b are connected to each other and are electrically connected to each other in the base metal. The lead wires 9a and 9b travel in the opposite direction to the wire helical standing body 3 and are connected to an external power source.

As shown in FIG. 2, both ends of the wire rod constituting the wire rod helical riser 3 are drawn to face the base metal 7, and among them, the wire rod drawn out from the top of the wire rod helical riser 3 is wired. The helical standing body 3 is drawn out to pass through, and the emitter coating coil 21 is preferably installed to be inserted therein. In this case, the emitter coating coil 21 is not separated from the wire helical standing body 3. An end of the emitter coating coil 21 may be welded to the base metal 7, but may not be welded. 2 or 3 shows that one emitter coating coil 21 is embedded inside the wire helical standing body 3, but another emitter coating coil may be further embedded inside the emitter coating coil. Alternatively, two or more emitter coating coils 21 may be provided adjacent to each other without overlapping. By doing so, the amount of electron emission can be increased at a low voltage without increasing the length of the electrode, so that high brightness suitable for illumination can be achieved without sacrificing the amount of light.

As shown in FIGS. 3 and 4, the lead wires 9a and 9b are glass beads 11 on the glass stem 11 and are coupled to the glass tube 17 by the glass stem 11. Glass beading is made by inserting the lead wires 9a and 9b of the cold cathode electrode 1 and the gas injection pipe 15 into the glass stem 11 and melting the glass on the upper end of the glass stem 11. The glass bead 13 remains at the bonded portion. By doing so, the sealing between the glass tube 17 and the lead wires 9a and 9b of the cold cathode electrode 1 can be easily performed.

In the present invention, tungsten or tungsten alloy is difficult to be plasticized and difficult to be formed into a cup-shaped electrode due to its low formability, but it is easy to process the coil shape after drawing it into a wire rod. The present invention has been conceived in that it can form a cup-shaped electrode having a low sputtering coefficient and a work function when stacked in a multilayer.

As described above, according to the present invention, the wire rod helical standing body 3 may be formed of tungsten or tungsten alloy having a small sputtering coefficient and work function, thereby increasing the life of a fluorescent lamp and inducing an initial discharge with a low starting voltage. have. In addition, by installing an emitter coating coil inside the wire helical standing body 3, it is possible to maintain the amount of discharge (electron emission) necessary for illumination at a low voltage in a normal state (more than 10mA).

As can be seen with reference to FIGS. 4 and 5, in a cold cathode fluorescent lamp, when an alternating voltage is applied across the electrode 1, electron emission is caused by an electric field from the electrodes, which is not caused by heat. Heat is not necessary because it is made by electric field. Initially, a small amount of electrons remaining inside the glass tube 17 strikes the electrode, and electrons start to be emitted from the electrode. Once the electrons start to be emitted, the emitted electrons strike the electrode again and continue to discharge. The electrons attracted to the anode and mercury present in the glass tube collide with each other by the discharge, and ultraviolet rays are emitted. The ultraviolet rays excite the fluorescent layer of the glass tube 17, and the fluorescent layer of the glass tube 17 emits visible light. Therefore, in order to satisfy high brightness and long life at the same time, the electron emission must be made easily as in the present invention. In the present invention, the electrode material was made of tungsten (W) having the highest melting point compared to the work function, and in consideration of the difficulty of plastic working of tungsten, a wire drawn and spirally wound were used. The wound coils emit electrons across the surface. Therefore, when the tungsten (W) is spirally formed and the coil diameter is sufficiently large as shown in the drawing and the windings are closely adhered to each other, when the emitter coating coil is embedded therein, the electron emission area is larger than that at the cup electrode. When the electrons in the lamp used for lighting impinge on the electrode, the energy is very high, more than 10 eV. Therefore, in order to realize a cold cathode fluorescent lamp for lighting, the material of the electrode is made of tungsten (W), and the electron emission area is increased. Most preferably, the shape is spiraled. However, it is difficult to use it for lighting since only the tungsten wound spirally has a high discharge holding voltage and a small discharge amount. However, when inserting the emitter coating coil coated with the emitter inside the tungsten or tungsten alloy wire helical standing body as in the present invention, it is possible to easily achieve a tube current of 10 mA or more required for illumination while maintaining a low discharge holding voltage. will be.

1 cold cathode electrode 3 wire rod helical standing body
5: emitter 7: base metal
9a, 9b: lead wire 11: glass stem
12: glass wirestem assembly 13: glass beads
15 gas injection pipe 17 glass tube
19: thin wire coil 21: emitter coated coil
23: cap 25: insulator

Claims (4)

In the cold cathode fluorescent lamp provided with a cold cathode electrode for emitting electrons across the glass tube formed on the inner wall of the fluorescent layer,
The cold cathode electrode,
A base metal 7 coupled to the ends of the lead wires 9a and 9b for introducing power,
A wire helical standing body (3) formed by winding a tungsten or tungsten alloy wire in a helical structure along the shape of a cup and connected to the base metal 7 so as to stand in the glass tube length direction (3). )Wow,
An emitter coating coil 21 inserted into the wire helical standing body 3 and having an emitter 5 applied to a surface thereof to induce electron emission,
Both ends of the wire rod constituting the wire rod helical riser 3 are drawn toward the base metal 7, and the wire rod drawn out from the top of the wire rod helical riser 3 is inside the wire helical riser 3. Cold cathode fluorescent lamp for illumination characterized in that it is installed so that the emitter coating coil 21 is inserted into the wire rod passing through the wire rod helical standing body (3).
The method of claim 1,
The lead wire (9a, 9b) is connected to two, the cold cathode fluorescent lamp for illumination, characterized in that connected to be electrically shorted to each other in the base metal (7).
The method of claim 1,
The base metal (7) is a cold cathode fluorescent lamp for illumination, characterized in that the rod-shaped or bead-shaped running in the vertical direction with respect to the lead wire (9a, 9b).
The method of claim 1,
The emitter coating coil 21 forms a thin wire coil 19 using a tungsten thin wire thinner than the wire helical standing body 3, and then winds the thin wire coil 19 in a spiral shape again. The thin wire coil is formed in a helical structure, and one or two or more emitters 5 selected from cesium oxide, barium oxide, strontium oxide, yttrium oxide, or magnesium oxide are coated on the surface of the thin wire coil 19. Cold cathode fluorescent lamp for illumination, characterized in that.

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