KR101159366B1 - Fluirescent lamp and backlight assembly having the same and liquid crystal display device - Google Patents

Abstract

The present invention discloses a fluorescent lamp, a backlight assembly and a liquid crystal display device having the same, which can improve discharge efficiency by forming an electrode including a plurality of metal layers having a low work function. The disclosed fluorescent lamp of the present invention comprises a glass tube, a fluorescent material applied to the inner surface of the glass tube, and a multi-layered electrode disposed inside both sides of the glass tube.

Multi-layer structure, secondary electron emission, electrode, work function

Description

Fluorescent lamp, backlight assembly and liquid crystal display device having the same {FLUIRESCENT LAMP AND BACKLIGHT ASSEMBLY HAVING THE SAME AND LIQUID CRYSTAL DISPLAY DEVICE}

Figure 1a is a perspective view of a cold cathode fluorescent lamp of the conventional backlight assembly.

FIG. 1B is a cross-sectional view taken along the line II ′ of FIG. 1A; FIG.

2A is an exploded perspective view illustrating an edge type liquid crystal display device according to an embodiment of the present invention.

FIG. 2B is a cross-sectional view taken along the line II-II 'of FIG. 2A;

3A is an exploded perspective view illustrating a direct type liquid crystal display device according to another embodiment of the present invention.

3B is a cross-sectional view taken along the line III-III 'of FIG. 3A;

4 is a graph showing the relationship between the lamp voltage and the lamp current according to the electrode material of the present invention.

5 is a graph showing the amount of mercury consumption per material of the electrode according to the present invention.

* Description of the symbols for the main parts of the drawings *

110: liquid crystal panel 120: backlight assembly

130: optical sheet 150: fluorescent lamp

170: Light guide plate 190: Bottom case

200, 200 ': first and second electrodes 201, 202, and 203: first to third electrode layers

201 ', 202', and 203 ': fourth to sixth electrode layers

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly, to a fluorescent lamp capable of improving discharge efficiency by forming an electrode including a plurality of metal layers having a low work function, and a backlight assembly and a liquid crystal display having the same.

CRT (Cathode Ray Tube), one of the widely used display devices, is mainly used for monitors such as TVs, measuring devices, information terminal devices, etc., but due to the weight and size of the CRT itself, the miniaturization and weight of electronic products Could not actively respond to the response.

As a solution to this problem, the liquid crystal display device has an advantage that it is possible to realize a light and short and small power consumption compared to the CRT. In particular, liquid crystal displays using thin film transistors have been used in various fields in the notebook PC and monitor market as well as in recent years since they have achieved high quality, large size, and color display screen comparable to CRTs.

The liquid crystal display device includes a liquid crystal panel for displaying an image and a driving circuit for driving the liquid crystal panel.

Since the liquid crystal display is not a self-luminous display, a back light assembly is required.

1A is a perspective view illustrating a cold cathode fluorescent lamp of a conventional backlight assembly, and FIG. 1B is a cross-sectional view taken along the line II ′ of FIG. 1A.

As shown in FIGS. 1A and 1B, a conventional cold cathode fluorescent lamp (CCFL) 50 includes a glass tube 51 and first and second electrodes disposed at both ends of the glass tube 51. 52 and 52 ', first and second power lead wires 53 and 53' as connecting means for applying voltage to the first and second electrodes 52 and 52 ', and an inner wall of the glass tube 51 And a mixed gas 55 injected into the glass tube 51 and made of neon (Ne), argon (Ar), mercury (Hg), and the like.

The first and second electrodes 52 and 52 'use nickel (Ni) which is soft and has excellent workability.

When the cold cathode fluorescent lamp 50 applies a voltage between the first and second electrodes 52 and 52 ', electrons present in the glass tube 51 are applied to the first and second electrodes 52 and 52'. The first electrons move at high speed and collide with the first and second electrodes 52 and 52 'to emit secondary electrons. As a result, discharge starts. Electrons flowing by the discharge collide with mercury electrons in the glass tube 51 to generate ultraviolet rays, and the ultraviolet rays excite the fluorescent material 54 to emit visible light.

However, the cold cathode fluorescent lamp 50 is a mixture in which metal atoms or molecules constituting the first and second electrodes 52 and 52 'are discharged and discharged in the glass tube 51 by sputtering during driving. Since the amalgam is combined with the gas 55 to form amalgam, the first and second electrodes 52 and 52 'itself and the mixed gas 55 are consumed by prolonged use, thereby reducing the lifespan. Accordingly, the first and second electrodes 52, 52 'using nickel (Ni) as a material have a problem in that the discharge efficiency is lowered by sputtering, and eventually, the life of the cold cathode fluorescent lamp 50 is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fluorescent lamp that lowers a discharge voltage and improves discharge efficiency by forming an electrode including a plurality of metal layers having a low work function, and a backlight assembly and a liquid crystal display device having the same.

In order to achieve the above object, the light source according to the present invention,

Glass tubes;

A fluorescent material coated on the inner surface of the glass tube;

It includes; a multi-layered electrode disposed inside both sides of the glass tube.

The backlight assembly according to the present invention,

A fluorescent lamp disposed on a side thereof and including an electrode having a multilayer structure; And

And a light guide plate disposed on the same plane as the light source and converting light into a surface light source.

In the liquid crystal display device according to the present invention,

A fluorescent lamp which emits light and has a multi-layered electrode therein; And

It includes; a liquid crystal panel for displaying a predetermined image using the light supplied from the fluorescent lamp.

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

FIG. 2A is an exploded perspective view illustrating an edge type liquid crystal display device according to an exemplary embodiment of the present invention, and FIG. 2B is a cross-sectional view taken along the line II-II ′ of FIG. 2A.

As shown in FIGS. 2A and 2B, the liquid crystal display according to the exemplary embodiment includes a liquid crystal panel 110 displaying an image and a backlight assembly 120 providing light to the liquid crystal panel 110. It is configured to include.

The backlight assembly 120 includes a bottom case 190, a light guide plate 170 disposed on the bottom case 190 to guide light forward, and a side surface of the light guide plate 170 to emit light. And a cold cathode fluorescent lamp 150 and an optical sheet 130 disposed on the light guide plate 170 to diffuse and collect light.

The backlight assembly 120 further includes a reflector (not shown) that is attached or coated on the bottom case 190 to reflect light.

The cold cathode fluorescent lamp 150 includes a transparent glass tube 151 having both ends opened, first and second power lead wires 153 and 153 ′ drawn out from both ends of the glass tube 151, and the first and second 2, the first and second electrodes 200 and 200 ′ connected to the power supply leads 153 and 153 ′, the fluorescent material 154 applied to the inner wall of the glass tube 151, and the inside of the glass tube 151. And a mixed gas 155.

Bead glass 156 is provided on the first and second power lead wires 153 and 153 ′ in the opened regions at both ends of the glass tube 151.

The bead glass 156 serves to prevent the mixed gas 155 from leaking from the glass tube 151 to the outside.

The mixed gas 155 generates invisible light by discharge. The mixed gas 155 collides with electrons moving inside the glass tube 151 to generate invisible light and mercury, and a panning effect of the cold cathode fluorescent lamp 150. Trace amounts of argon, neon, xenon, krypton, and the like, for lowering the driving voltage are included.

The fluorescent material 154 converts an invisible ray generated in the glass tube 151, for example, an ultraviolet ray, into visible ray.

The first electrode 200 includes first to third electrode layers 201, 202, and 203, and the second electrode 200 ′ is fourth to sixth electrode layers 201 ′, 202 ', and 203'. )

The first and fourth electrode layers 201 and 201 'are made of nickel (Ni), the second and fifth electrode layers 202 and 202' are made of niobium (Nb), and the third and sixth electrode layers. 203 and 203 'are made of magnesium oxide (MgO).

The first and second positive electrodes 200 and 200 ′ have a multilayer structure of nickel (Ni), niobium (Nb), and magnesium oxide (MgO). The niobium having a lower work function than a conventional nickel (Ni) metal ( Nb) and magnesium oxide (MgO) to reduce the power consumption and to improve the lifespan to improve the discharge efficiency.

The niobium (Nb) and magnesium oxide (MgO) have a lower work function than the nickel (Ni) to facilitate secondary electron emission at low voltage, but the metal atoms of the niobium (Nb) and coral magnesium (MgO) are sputtered. Alternatively, there is a disadvantage in that the time consumed by the combination of the molecules and the mixed gas 155 is fast. Therefore, since the first and fourth electrode layers 201 and 201 'are formed of nickel (Ni), the power consumption can be reduced while extending the time consumed.

The method of forming the first and second positive electrodes 200 and 200 'may include a nickel (Ni) plate of the first and fourth electrode layers 201 and 201' and a niobium of the second and fifth electrode layers 202 and 202 '. (Nb) Cold rolling and hot rolling are repeated several times by rolling the original plate under high pressure, and then attached in the form of plywood.

Then, magnesium oxide (MgO) of the third and sixth electrode layers 203 and 203 'is deposited on the niobium Nb of the second and fifth electrode layers 202 and 202' and deposited by applying heat.

Improvement of the performance of the cold cathode fluorescent lamp 150 by the work function will be described in detail with reference to the graphs of FIGS. 5 and 6.

In an edge type liquid crystal display according to an exemplary embodiment, at least one metal material having a work function lower than that of nickel (Ni) is stacked inside a nickel (Ni) metal to form a first and second electrode 200 having a multilayer structure. , 200 ') is provided with a cold cathode fluorescent lamp 150 can be improved life and power consumption can be reduced.

3A is an exploded perspective view illustrating a direct type liquid crystal display according to another exemplary embodiment of the present invention, and FIG. 3B is a cross-sectional view taken along the line III-III ′ of FIG. 3A.

As shown in FIGS. 3A and 3B, the same components among the components of the edge type liquid crystal display according to the exemplary embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted.

In the direct type love display device according to another exemplary embodiment, a plurality of cold cathode fluorescent lamps 250 are disposed on the bottom case 190 at predetermined intervals.

The cold cathode fluorescent lamp 250 includes a transparent glass tube 251 having both ends opened, first and second power lead wires 253 and 253 ′ drawn from both ends of the glass tube 251, and the first and second 2, the first and second electrodes 300 and 300 ′ connected to the power supply wires 253 and 253 ′, the fluorescent material 254 applied to the inner wall of the glass tube 251, and the inside of the glass tube 251. Mixed gas 255.

The first electrode 300 includes the first to third electrode layers 301, 302, and 303, and the second electrode 300 ′ is the fourth to sixth electrode layers 301 ′, 302 ′, and 303 ′. )

The first and fourth electrode layers 301 and 301 'are made of nickel (Ni), the second and fifth electrode layers 302 and 302' are made of niobium (Nb), and the third and sixth electrode layers. 303 and 303 'are made of magnesium oxide (MgO).

The niobium (Nb) and magnesium oxide (MgO) are metal materials having a lower work function than the nickel (Ni), and thus, secondary electrons can be easily emitted at low voltages, thereby reducing power consumption. The first and fourth electrode layers 301 , 301 ') may be formed of a nickel (Ni) metal material to extend the time consumed by the niobium (Nb) and magnesium oxide (MgO) by sputtering.

Accordingly, the direct type liquid crystal display according to another exemplary embodiment of the present invention stacks at least one metal material having a work function lower than that of nickel (Ni) inside the nickel (Ni) metal, thereby forming the first and second electrodes having a multilayer structure. The cold cathode fluorescent lamp 250 including 300 and 300 ′ is provided to reduce power consumption and improve lifespan.

The first and second electrodes 200, 200 ′, 300, and 300 ′ of the cold cathode fluorescent lamps 150 and 250 according to the exemplary embodiment of the present invention may have niobium (Nb) and magnesium oxide (Ni) inside a nickel (Ni) metal. Although MgO) is a stacked structure, metal materials such as tungsten (W), molybdenum (Mo), and tantalum (Ta) having a lower work function than nickel (Ni) may be stacked.

The cold cathode fluorescent lamps 150 and 250 form a surface area of the first and second electrodes 200, 200 ′, 300 and 300 ′ and the first and second electrodes 200, 200 ′, 300 and 300 ′. Depending on the material, life, brightness and power consumption are greatly affected.

4 is a graph showing the relationship between the lamp voltage and the lamp current according to the electrode material of the present invention.

As shown in FIG. 2B and FIG. 4, the experimental conditions are 2.0 mm of the inner diameter of the glass tube 151, 348 mm of the length of the glass tube 151, and the pressure of the mixed gas 155 is 60 Torr. The lamp current and lamp voltage were compared while changing to silver nickel (Ni), tungsten (W), niobium (Nb), molybdenum (Mo), and tantalum (Ta). As a result, the performance of the cold cathode fluorescent lamp 151 was greatly improved in the order of the nickel (Ni) electrode, tungsten (W) electrode, niobium (Nb) electrode, molybdenum (Mo) electrode, and tantalum (Ta) electrode.

The performance improvement of the cold cathode fluorescent lamps 150 and 250 is related to a work function, and the lower the work function of the metal constituting the first and second electrodes, the more electrons can be emitted at a lower voltage. Power consumption of the cathode fluorescent lamps 150 and 250 can be greatly reduced. At this time, the work function for each metal is approximately 4.84 eV of nickel (Ni), 4.5 eV of tungsten (W), 4.3 eV of niobium (Nb), 4.27 eV of molybdenum (Mo), and 4.12 eV of tantalum (Ta).

5 is a graph showing mercury consumption per material of an electrode according to the present invention.

As shown in FIGS. 2B and 5, the graph shows the first and second electrode materials of the cold cathode fluorescent lamps 150 and 250 as nickel (Ni), tungsten (W), niobium (Nb), and molybdenum (Mo). And tantalum (Ta) and the result of the experiment. As the consumption of mercury increases, the lifetime of the cold cathode fluorescent lamps 150 and 250 has the shortest nickel (Ni) electrode, tungsten (W) electrode, niobium (Nb) electrode, molybdenum (Mo) electrode, and tantalum. (Ta) increased in the order of the electrode.

In an exemplary embodiment of the present invention, a liquid crystal display device includes a first electrode and a second electrode having a multilayer structure in which at least one metal material having a work function (4.84 eV) lower than nickel (Ni) is stacked inside a nickel (Ni) metal material. The cold cathode fluorescent lamps 150 and 250 including 200, 200 ', 300, and 300' are provided to reduce power consumption and improve lifespan. Therefore, the discharge efficiency of the liquid crystal display device can be improved.

As described above, according to the present invention, a power consumption is increased by providing an electrode having a multilayer structure in which at least one metal material having a work function (4.84 eV) lower than that of nickel (Ni) is disposed inside the nickel (Ni) metal material. It has the effect of reducing and improving life.

Those skilled in the art through the above description will be capable of various changes and modifications without departing from the spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (12)

Glass tubes; A fluorescent material coated on the inner surface of the glass tube; First and second power lead wires drawn out of both sides of the glass tube; Bead glass provided in regions opened at both sides of the glass tube and provided on the first and second power lead wires; Disposed inside both sides of the glass tube and including electrodes having first to third electrode layers, The first electrode layer is made of a nickel (Ni) metal material, and the second electrode layer is formed of tungsten (W), niobium (Nb), molybdenum (Mo), which have a lower work function than the first electrode layer, inside the first electrode layer. The fluorescent lamp of any one of a tantalum (Ta) and the third electrode layer is made of magnesium oxide (MgO). delete delete A glass tube disposed on a side surface, a fluorescent material applied to an inner surface of the glass tube, first and second power lead wires drawn out from both sides of the glass tube, and regions opened on both sides of the glass tube, A bead glass provided on a second power supply lead and an electrode disposed inside both sides of the glass tube and having first to third electrode layers, wherein the first electrode layer is made of a nickel (Ni) metal material, and The second electrode layer is formed of a metal material of any one of tungsten (W), niobium (Nb), molybdenum (Mo), and tantalum (Ta) having a lower work function than the first electrode layer inside the first electrode layer. The three electrode layer includes a fluorescent lamp made of magnesium oxide (MgO); And And a light guide plate disposed on the same plane as the fluorescent lamp and converting light into a surface light source. delete delete A glass tube, a fluorescent material applied to the inner surface of the glass tube, first and second power lead wires drawn out of both sides of the glass tube, and regions open to both sides of the glass tube, And bead glass provided on the first and second power lead wires, and disposed inside both sides of the glass tube, and having electrodes having first to third electrode layers, wherein the first electrode layer is made of a nickel (Ni) metal material. The second electrode layer is formed of a metal material of any one of tungsten (W), niobium (Nb), molybdenum (Mo), and tantalum (Ta) having a lower work function than the first electrode layer inside the first electrode layer. The third electrode layer includes a plurality of fluorescent lamps made of magnesium oxide (MgO); And And an optical sheet disposed on the plurality of fluorescent lamps for diffusing and condensing light. delete delete A light tube which emits light and which is coated on the inner surface of the glass tube, first and second power lead wires which are drawn out of both sides of the glass tube, and regions which are opened on both sides of the glass tube, A bead glass provided on a second power supply lead and an electrode disposed inside both sides of the glass tube and having first to third electrode layers, wherein the first electrode layer is made of a nickel (Ni) metal material, and The second electrode layer is formed of a metal material of any one of tungsten (W), niobium (Nb), molybdenum (Mo), and tantalum (Ta) having a lower work function than the first electrode layer inside the first electrode layer. The three electrode layer includes at least one fluorescent lamp made of magnesium oxide (MgO); And And a liquid crystal panel displaying a predetermined image by using the light supplied from the fluorescent lamp. delete delete

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