KR100729805B1 - Complex electrode fluorescent lamp and back light unit of direct light type therewith - Google Patents

Abstract

According to the present invention, there is disclosed a U-shaped composite electrode fluorescent lamp and a direct light emitting backlight unit having such a composite electrode fluorescent lamp. The disclosed direct light emitting unit includes a reflector plate and a diffuser plate spaced apart from each other at predetermined intervals, at least one compound electrode fluorescent lamp disposed in parallel between the reflector plate and the diffuser plate, and the composite electrode fluorescent lamp. The composite electrode fluorescent lamp includes a tube having a phosphor layer coated on an inner circumferential wall, filled with a discharge gas, and having a U-shaped curved portion, a cold cathode electrode provided at both ends of the tube, and a curved portion of the composite electrode fluorescent lamp. An external electrode is disposed on an outer circumferential surface, and the cold cathode electrode and the external electrode of the composite electrode fluorescent lamp are electrically connected in parallel to the inverter, and the composite electrode fluorescent lamps are formed in two or more groups to each individual inverter. Connected.

According to the disclosed direct-emitting backlight, the number of cold-cathode fluorescent lamps used is reduced to reduce manufacturing costs, and the fluorescent lamp and the inverter can be electrically connected in parallel, so that a single inverter can supply power to several fluorescent lamps. In terms of luminance, better performance can be obtained.

Direct emission type, backlight unit, parallel, composite electrode

Description

Complex electrode fluorescent lamp and back light unit of direct light type therewith}

1 is an exploded perspective view showing an example of a conventional direct emitting type backlight unit employing a straight cold cathode fluorescent lamp,

FIG. 2 is a conceptual diagram illustrating an electrical connection state of the flat cold cathode fluorescent lamp of the backlight unit employing the conventional flat cold cathode fluorescent lamp of FIG. 1;

3 is a conceptual diagram illustrating an electrical connection state of a U-shaped cold cathode fluorescent lamp of a backlight unit employing a conventional U-shaped cold cathode fluorescent lamp;

4 is a conceptual diagram showing the electrical connection state of the U-shaped composite electrode fluorescent lamp according to an embodiment of the present invention,

5 is a cross-sectional view taken along line II ′ of FIG. 4;

6 is a cross-sectional view taken along the line II-II 'of FIG. 4;

7 is a conceptual diagram showing an electrical connection state of the U-shaped composite electrode fluorescent lamp according to another embodiment of the present invention,

8 is a conceptual diagram illustrating an electrical connection state of a U-shaped composite electrode fluorescent lamp according to another embodiment of the present invention.

<Description of Symbols for Major Parts of Drawings>

110: composite electrode fluorescent lamp 111: tube

112, 113: cold cathode electrode 114: inverter

116, 117: lead wire 118: curved portion

120: external electrode 122: phosphor layer

132, 133: capacitor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite electrode fluorescent lamp and a direct light emitting backlight unit having the same, and more particularly, to a combination of a cold cathode electrode and an external electrode, and electrically connecting these electrodes in parallel. The present invention relates to a U-shaped composite electrode fluorescent lamp driven and a direct-emitting backlight unit for LCD-TV having the same.

In general, a flat panel display is classified into a light emitting type and a light receiving type, and the light emitting type includes a cathode ray tube, an electroluminescent (EL) element, a plasma display panel (PDP), and the like. The light receiving type includes a liquid crystal display (LCD) and the like.

 Since the liquid crystal display itself is a light-receiving element that emits light and does not form an image, but receives light from the outside to form an image, a separate light source, for example, a backlight is installed to observe the image in a dark place.

The backlight for the liquid crystal display includes a direct light type for arranging a plurality of fluorescent lamps under the liquid crystal according to the installation form of the fluorescent lamp and an edge light type for installing the fluorescent lamp on the side of the light guide plate. Separated by. The fluorescent lamp may be a cold cathode fluorescent lamp (CCFL) having electrodes at both ends, and an external electrode fluorescent lamp (EEFL) having electrodes at both ends of the tube.

The edge emission type is a method of irradiating light from only one side, and thus the application of the edge emission type is not suitable for a large panel because it cannot satisfy the required luminance condition. Therefore, in recent years, the demand for a direct light emitting backlight using an external electrode is increasing, and research on this is being actively conducted.

1 is an exploded perspective view showing an example of a conventional backlight unit employing a direct light emission type.

As shown in the drawing, the conventional backlight unit employing a direct light emitting type is installed in the upper frame 41 and the lower frame 42 and the inner space formed by the upper frame and the lower frame to generate light and to be uniformly arranged with each other. A plurality of flat cold cathode fluorescent lamps 10, a diffuser plate 60 arranged above the fluorescent lamp 10 to diffuse light from the fluorescent lamp 10, and a lower portion of the fluorescent lamp 10. It includes a reflector plate 50 for reflecting light and a lamp holder 30 for supporting the fluorescent lamp 10 spaced apart from the lower frame 42 by a predetermined distance. Each fluorescent lamp 10 includes a tube 11 of glass material. In addition, a phosphor layer (not shown) is formed on an inner surface of the tube 11, and cold cathode electrodes 12 and 13 are formed at both ends of the tube 11.

2 is a view schematically showing an electrical connection state of a conventional cold cathode fluorescent lamp.

The cold cathode fluorescent lamp 10 is provided with a straight tube 11, the inner surface of the tube, although not shown, a fluorescent material is coated and sealed, cold cathode at both ends of the cold cathode fluorescent lamp 10 Electrodes 12 and 13 are mounted, respectively. As shown in FIG. 1, in the case of the direct emission type backlight unit, the plurality of cold cathode fluorescent lamps are disposed adjacent to and parallel to the reflective plate 50 at regular intervals. In this case, as shown in FIG. 2, in the conventional direct emission type backlight unit, the inverter 14 is individually connected to each of the cold cathode fluorescent lamps through the lead wires 16 and 17 connected to the cold cathode electrodes 12 and 13. The structure is mounted as.

However, the backlight unit using such a cold cathode fluorescent lamp requires a large number of cold cathode fluorescent lamps because each fluorescent lamp must be densely installed at a predetermined level on the reflector to obtain the required level of brightness. do.

In addition, in the case of a cold cathode fluorescent lamp according to the prior art, when a plurality of such fluorescent lamps are connected in parallel to a substrate and an AC power is applied, only a few lamps emit light. Each power supply, an individual inverter, must be driven. That is, the number of inverters corresponding to the number of fluorescent lamps is required. In this case, since the synchronization of the voltage waveforms output by each inverter is different, a strong electric field is formed between adjacent power supplies, which consumes unnecessary power, thereby reducing the efficiency of the backlight unit. There is a problem of this deterioration.

The backlight unit employing the U-shaped cold cathode fluorescent lamp of FIG. 3 is invented to solve the problem of the backlight unit employing the conventional straight cold cathode fluorescent lamp, and the conventional cold cathode as shown in FIG. It is equipped with the method which improved the electrical connection state of a fluorescent lamp.

The cold cathode fluorescent lamp 10 'of FIG. 3 has a U-shaped tube 11'. That is, the curved part 18 is formed in the middle part of the longitudinal direction of a tube. Cold cathode electrodes 12 ', 13' are respectively provided at each end of the curved tube, and these cold cathode electrodes are electrically connected to the inverter 14 'via lead wires 16', 17 '.

Since the U-shaped cold cathode fluorescent lamp is irradiated with light corresponding to two straight fluorescent lamps as one fluorescent lamp, the brightness of the U-shaped cold cathode lamp is almost the same as that of the linear fluorescent lamp of FIG. 2, while the number of cold cathode fluorescent lamps used is halved. There is an improvement in that it can be reduced.

However, the number of inverters used is not reduced at all because the backlight unit having the U-shaped cold cathode fluorescent lamp is connected to each lamp. Therefore, as in the case of the flat cold cathode fluorescent lamp, the cost increases. The problems as described above due to the electric field formation between the inverters have not been solved.

The present invention is to solve the problems described above, while maintaining a constant brightness, while reducing the number of fluorescent lamps used, and dramatically reducing the number of inverters connected to the fluorescent lamps to reduce the production cost, use It is an object of the present invention to provide a multi-electrode fluorescent lamp capable of reducing power consumption and increasing the efficiency of a backlight unit and a direct-emitting backlight unit having the same.

The composite electrode fluorescent lamp of the present invention for achieving the above object is a tube having a phosphor layer coated on the inner circumferential wall and filled with a discharge gas, and having a U-shaped curved portion, and a cold cathode electrode provided at both ends of the tube; It includes an external electrode installed on the outer peripheral surface of the tube.

The external electrode is preferably installed on the outer circumferential surface of the curved portion of the tube.

The curved portion is preferably formed in the center portion in the longitudinal direction of the tube.

The external electrode may be formed of any one material selected from the group consisting of nickel plating, silver paste coating, lead-free material, copper tape, aluminum tape, indium tin oxide (ITO), and SnO ₂ . Can be.

In addition, both ends of the tube is preferably arranged side by side.

In order to achieve the above object, a direct light emitting type backlight unit includes: a reflector plate and a diffuser plate spaced apart from each other at a predetermined interval, and at least one composite electrode fluorescent lamp disposed in parallel between the reflector plate and the diffuser plate; And an inverter electrically connected to the composite electrode fluorescent lamp, wherein each of the composite electrode fluorescent lamps has a tube having a phosphor layer coated on an inner circumferential wall, filled with discharge gas, and having a U-shaped curved portion, and both ends of the tube. And a cold cathode electrode installed at an outer surface of the tube, and an outer electrode provided at an outer circumferential surface of the tube, wherein the cold cathode electrode and the external electrode of each of the composite electrode fluorescent lamps are electrically connected in parallel to the inverter, and the composite electrode fluorescent lamp They form two or more groups and are connected to individual inverters for each group.

The external electrode is preferably disposed on the outer circumferential surface of the curved portion of the tube.

A plurality of composite electrode fluorescent lamps may be electrically connected in parallel to the inverter.

The curved portion is preferably formed in the center portion in the longitudinal direction of the tube.

On the other hand, a capacitor may be further connected to the outside of each of the cold cathode electrode.

In addition, both ends of the tube is preferably parallel.

Here, the external electrode is preferably formed of any one material selected from the group consisting of nickel plating, sylver paste coating, lead-free material, copper tape, aluminum tape, ITO, SnO ₂ .

In addition, the voltage applied to the cold cathode electrodes provided at both ends of the tube connected in parallel to one inverter is applied such that a phase difference of 180 degrees is generated between the voltage applied to the first electrode and the voltage applied to the second electrode. Voltage.

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

FIG. 4 is a conceptual diagram illustrating an electrical connection state of a composite electrode fluorescent lamp according to the present invention, and illustrates an exemplary partial composite electrode fluorescent lamp among a plurality of composite electrode fluorescent lamps having the same structure.

Referring to the drawings, the composite electrode fluorescent lamp 110 according to a preferred embodiment of the present invention, the tube 111 having a phosphor layer is applied to the inner peripheral wall, the discharge gas is filled and the U-shaped curved portion 118 and And cold cathode electrodes 112 and 113 provided at both ends of the tube, and external electrodes 120 provided on the outer circumferential surface of the curved portion.

In more detail, the fluorescent lamp 110 has a sealed discharge space and has a tube 111 made of a transparent dielectric, and cold cathode electrodes formed at both ends of the tube 111 to cause dielectric barrier discharge. 112 and 113, and as shown in FIG. 6, a phosphor layer 122 is formed on an inner circumferential wall of the tube 111. That is, the composite electrode fluorescent lamp according to the present invention is similar to the general cold cathode fluorescent lamp in that the cold cathode electrodes 112 and 113 are respectively provided at both ends of the tube to form a cold cathode fluorescent lamp. Do. The tube 111 is preferably of a glass material.

On the other hand, the composite electrode fluorescent lamp of the present invention has a curved portion 118 bent in a U-shape in the middle of the longitudinal direction of the tube of the fluorescent lamp, in addition to the general linear cold cathode fluorescent lamp, the overall shape of the fluorescent lamp is U-shaped Achieve. Therefore, both ends of the fluorescent lamps are directed in the same direction, not in opposite directions.

In this case, it is preferable that both ends of the tube have the same length with respect to the curved portion, so that one electrode portion is aligned without protruding in the longitudinal direction than the other electrode portion. In addition, it is preferable that both ends of the bent tube are placed next to each other to maintain a constant distance from each other.

Therefore, the U-shaped fluorescent lamp has a structure similar to that in which one end of each of the two straight fluorescent lamps is connected to each other and arranged side by side.

On the other hand, the specific structure of the pair of cold cathode electrodes 112 and 113 provided at the closed both ends of the tube 111 is the same as the structure of the cold cathode electrode of the common cold cathode fluorescent lamp, so the present invention will be described in detail. Omit.

In addition to the cold cathode electrodes 112 and 113, an external electrode 120 is installed on an outer circumferential surface of the tube 111. The external electrode 120 is preferably mounted on the outer circumferential surface of the curved portion 118 bent in a U-shape among the outer circumferential surfaces of the tube 111 for uniformity of luminance of the fluorescent lamp.

Therefore, the composite electrode fluorescent lamp according to the present invention has a complex structure having both the cold cathode electrode of the cold cathode fluorescent lamp and the external electrode of the external electrode fluorescent lamp.

In this case, since the external electrode 120 is disposed in the middle of the tube, the external electrode 120 is preferably a belt type external electrode. On the other hand, the external electrodes are nickel plated, silver paste coating (leader coating), lead-free materials (Sn-Ag-Cu, Sn-Ag, Sn-Cu-Ni, Sn-Bi, Sn-Bi-Sb, Sn-Ag) -Cu-Bi, Sn-Sb), copper tape, aluminum tape, SnO ₂ It may be formed of any material selected from the group consisting of. However, in order to prevent the light irradiated due to the external electrode from being blocked, to guarantee uniformity of luminance, the external electrode may be made of ITO, which is a transparent conductor.

5 is a cross-sectional view taken along the line II ′ of FIG. 4, and FIG. 6 is a cross-sectional view taken along the line II-II ′ of FIG. 4.

According to FIG. 5, the internal cross section of the fluorescent lamp of the portion where the external electrode 120 is disposed is well revealed. In other words, the outer electrode 120 is disposed on the outer circumferential surface of the tube coated with the phosphor layer 122 on the inner circumferential surface, preferably on the outer circumferential surface of the curved portion 118 of the tube. The external electrode 120 may surround the entire outer circumferential surface of the curved portion, or may cover only a portion of the outer circumferential surface.

Meanwhile, in the portion of the outer circumferential surface of the tube 111 where no external electrode is disposed, as shown in FIG. 6, the outer electrode is not disposed on the outer circumferential surface of the tube 111 on which the phosphor layer 122 is coated on the inner circumferential wall. Is directly exposed.

On the other hand, the direct emission type backlight unit having the composite electrode fluorescent lamp having such a structure, the reflector plate 50 and the diffusion plate 70 are spaced apart from each other at predetermined intervals similar to the conventional backlight unit shown in FIG. In addition, as shown in FIG. 4, at least one composite electrode fluorescent lamp 110 disposed in parallel between the reflecting plate and the diffusion plate, and an inverter 114 electrically connected to the composite electrode fluorescent lamp. The composite electrode fluorescent lamp 110 has a phosphor layer coated on an inner circumferential wall, a discharge gas is filled, and a tube 111 having a U-shaped curved portion and a cold cathode electrode 112 installed at both ends of the tube. And an external electrode 120 installed on an outer circumferential surface of the tube 111, wherein the inverter 114 is parallel to the cold cathode electrodes 112 and 113 and the external electrode of the composite electrode fluorescent lamp. Electrical connection.

In this case, the external electrode 120 of each composite electrode fluorescent lamp is preferably disposed in the curved portion 118 of the tube, particularly in the outer circumferential surface of each tube 111.

For one inverter, the cold cathode electrodes 112 and 113 of each composite electrode fluorescent lamp are connected to the inverter 114 via the lead wire 116, and the external electrode 120 of each composite electrode fluorescent lamp is connected to the lead wire ( The cold cathode electrode and the external electrode of the fluorescent lamps are electrically connected in parallel with the inverter.

7 and 8 illustrate an electrical connection state of the U-shaped composite electrode fluorescent lamp according to another embodiment of the present invention. In FIG. 7, a capacitor is connected to the outside of either of the two cold cathode electrodes 112 and 113. 8, the capacitor is connected to the outer side of the two cold cathode electrodes 112 and 113, respectively.

Therefore, since a plurality of composite electrode fluorescent lamps can be electrically connected to one inverter 114 in parallel, it is not necessary to separately install an inverter for each composite electrode fluorescent lamp.

Since the cold cathode electrode is connected in parallel to the inverter through a capacitor, the problem of parallel connection with a conventional cold cathode fluorescent lamp alone can be compensated.

Although not shown in the drawings, a lead wire for electrical connection of the composite electrode fluorescent lamp is installed inside the lamp holder 30 of the conventional backlight unit shown in FIG. 1 to connect each electrode of the fluorescent lamp to the inverter. Can be.

If the capacity of the inverter is large enough, a plurality of composite electrode fluorescent lamps may be electrically connected in parallel to one inverter using only one inverter in one backlight unit. Optionally, according to the necessity of using an inverter having a smaller capacity, a backlight unit for grouping a plurality of composite electrode fluorescent lamps in one backlight unit and connecting individual inverters in parallel for each group may be considered.

According to the composite electrode fluorescent lamp of the present invention as described above and the direct emission type backlight unit having the same, the following effects can be obtained.

First, it is possible to reduce the number of fluorescent lamps used without reducing the brightness, thereby reducing the production cost.

Secondly, since the number of inverters used can be reduced, production cost is reduced and the internal structure of the backlight unit is simplified.

third. Since the composite electrode fluorescent lamp includes the characteristics of the cold cathode fluorescent lamp and the external electrode fluorescent lamp in combination, there is no need to separately install the external electrode fluorescent lamp.

Fourth, interference between inverters by using a plurality of inverters is eliminated, thereby reducing power consumption and improving backlight efficiency.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (13)

A tube having a phosphor layer coated on the inner circumferential wall, filled with a discharge gas, and having a U-shaped curved portion; A cold cathode electrode provided at both ends of the tube; An external electrode disposed on an outer circumferential surface of the tube, The external electrode is a composite electrode fluorescent lamp disposed on the outer peripheral surface of the curved portion of the tube. delete The composite electrode fluorescent lamp of claim 1, wherein the curved portion is formed at the center portion in the longitudinal direction of the tube. The method of claim 1, wherein the external electrode is formed of any one material selected from the group consisting of nickel plating, silver paste coating, lead-free material, copper tape, aluminum tape, indium tin oxide (ITO), and SnO ₂ . Composite electrode fluorescent lamp, characterized in that. The composite electrode fluorescent lamp of claim 1, 3 or 4, wherein both ends of the tube are parallel to each other. Directly emitting light includes a reflector plate and a diffuser plate spaced apart from each other at a predetermined interval, at least one composite electrode fluorescent lamp disposed in parallel between the reflector plate and the diffuser plate, and an inverter electrically connected to the composite electrode fluorescent lamp. As a type backlight unit, Each of the composite electrode fluorescent lamps includes: a tube having a phosphor layer coated on an inner circumferential wall, filled with a discharge gas, and having a U-shaped curved portion; A cold cathode electrode provided at both ends of the tube; It includes an external electrode installed on the outer peripheral surface of the tube, The external electrode is disposed on the outer circumferential surface of the curved portion of the tube, The cold cathode electrode and the external electrode of each of the composite electrode fluorescent lamps are electrically connected in parallel to the inverter, and the composite electrode fluorescent lamps are formed in two or more groups and connected to individual inverters for each group. Emission type backlight unit. delete The direct light emitting type backlight unit of claim 6, wherein a plurality of composite electrode fluorescent lamps are electrically connected in parallel to the inverter. The direct light-emitting type backlight unit of claim 6, wherein the curved portion is formed at the center portion in the longitudinal direction of the tube. The direct light emitting type backlight unit of claim 6, wherein a capacitor is further connected to an outer side of each of the cold cathode electrodes. 7. The direct electrode of claim 6, wherein the external electrode is formed of any one material selected from the group consisting of nickel plating, silver paste coating, lead-free material, copper tape, aluminum tape, ITO and SnO ₂ . Emission type backlight unit. 12. The direct light emitting backlight unit of claim 6, 8 or 11, wherein both ends of the tube are parallel to each other. The voltage applied to the cold cathode electrodes provided at both ends of the tube connected to one inverter in parallel to each other, the phase difference of 180 degrees between the voltage applied to the first electrode and the voltage applied to the second electrode The direct light-emitting backlight unit, characterized in that is applied to generate.

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