KR100930646B1 - External electrode fluorescent lamp and liquid crystal display device using the same - Google Patents

Abstract

PURPOSE: An external electrode fluorescent lamp and a liquid crystal display device using the same are provided to maximize power efficiency, and luminous efficiency and a lifetime by adding an additive to increase glass characteristics and dielectric property. CONSTITUTION: In a device, a fluorescent layer(125) and a protective film(120) are formed on the inner side of the glass tube(114) and are sealed. An external electrode(116) is formed in order to cover the outer circumference at the both sides of the glass tube. The internal electrode is formed inside the end of the glass tube. A lead line is extended to the outside of the glass tube to connect power to the external electrode and internal electrode. A bead glass is formed in one side of the metal lead-line in order to seal the either end of glass tube. The inner electrode includes the metal lead-in line connected to the lead line and a dielectric coating layer.

Description

EXTERNAL ELECTRODE FLUORESCENT LAMP AND LIQUID CRYSTAL DISPLAY DEVICE USING THE SAME}

The present invention relates to an external electrode fluorescent lamp, and more particularly to an external electrode fluorescent lamp that can improve the brightness and life of the lamp and a liquid crystal display device using the same.

In recent information society, display devices are more important than ever as visual information transmission media, and many kinds of flat panel displays have been developed.

The flat panel display device includes a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), and an electroluminescence (EL). .

Among such flat panel display devices, liquid crystal displays have a wide range of applications due to their light weight, thinness, and low power consumption. In line with this trend, liquid crystal displays are being used as portable computers such as notebook PCs, office automation equipment, audio / video equipment, indoor and outdoor advertising display devices, etc. It is rapidly developing into anger.

Such a liquid crystal display device displays a desired image on a screen by adjusting a transmission amount of light incident on the display panel according to an image signal applied to a plurality of control switches arranged in a matrix form.

A general liquid crystal display device is composed of a liquid crystal display module and a driving circuit portion for driving the liquid crystal display module.

The liquid crystal display module includes a liquid crystal display panel in which liquid crystal cells are arranged in a matrix form between two glass substrates, and a backlight unit that irradiates light to the liquid crystal display panel.

Since most of the liquid crystal display devices are light-receiving elements that display images by controlling the amount of light source coming from the outside, a separate light source for illuminating the liquid crystal panel, that is, a backlight unit, is necessary. The unit is divided into the edge method and the direct method according to the position where the lamp unit is installed.

As a conventional light source, a Cold Cathode Fluorescent Lamp (CCFL) having an internal electrode inside the lamp body is mainly used. However, as a liquid crystal display device is enlarged in recent years, a cold cathode fluorescent lamp is required. The number is also increasing. However, since the internal electrode type fluorescent lamp requires a separate inverter for driving, as the number of lamps increases, the number of inverters increases, which increases the manufacturing cost.

Therefore, recently, an external electrode fluorescent lamp (EEFL) capable of driving a plurality of lamps in parallel with one inverter has been developed for cost reduction and driving stability.

Hereinafter, a conventional external electrode fluorescent lamp will be described with reference to the accompanying drawings.

1 is a perspective view showing a conventional external electrode fluorescent lamp, Figure 2 is a perspective view showing an external electrode fluorescent lamp when a voltage is applied.

1 and 2, the conventional external electrode fluorescent lamp 10 includes a glass tube in which an inert gas is enclosed therein, an external electrode formed to surround both ends of the glass tube, and a glass tube on the inner wall of the glass tube 14. A protective film for protecting 14) and a fluorescent layer 25 that is stimulated by ultraviolet rays formed by discharge to generate visible light are formed.

The inner space of the glass tube 14 is filled with a discharge gas for emitting light from the external electrode fluorescent lamp 10. The discharge gas is filled with a discharge gas consisting of neon (Ne) and argon (Ar) and mercury (Hg).

The light emission principle of the conventional external electrode fluorescent lamp is as follows. When an AC voltage is applied to the external electrodes 16 at both ends of the lamp and driven, an electric field is formed inside the lamp through the external electrodes 16. Accordingly, plasma is generated in the lamp internal space by the electric field. At this time, a conductive plasma environment is formed inside the glass tube 14 by the generated plasma, and the generated ultraviolet rays stimulate the fluorescent material of the fluorescent layer 25 to generate visible light. By this principle, the external electrode fluorescent lamp 10 emits light.

As shown in FIG. 2, when a voltage is applied to the external electrode fluorescent lamp 10, when the protective film 20 is formed in the external electrode part Ι as shown in FIG. 3A, the electrical resistance of the protective film 20 decreases due to firing conditions, thereby applying a high voltage. When the protective film 20 is charged, the wall charges are formed to face the center of the lamp from the external electrode 16, thereby increasing power consumption and lighting delay. In addition, as shown in FIG. 3B, the protective film charged in the protective film 20 and the fluorescent layer 25 portion (II) has a Coulomb force with mercury ions to penetrate mercury between the pores of the fluorescent layer 25 to shorten the life of the lamp. Has a problem.

In addition, as the external electrode fluorescent lamp 10 has recently been commercialized with the LCD employing the external electrode fluorescent lamp 10 and the size of the screen is enlarged, the external electrode fluorescent lamp used for this has a higher voltage. Therefore, the mercury injected into the external electrode fluorescent lamp 10 by being turned on for a long time is consumed, and thus the luminance is lowered, thereby reducing the lifetime.

In addition, although it is possible to increase the surface area of the electrode to improve the lifetime, there is a limitation in expanding the surface area of the electrode. In other words, when the length of the electrode is increased, the surface area of the electrode is extended and its life is long. However, since the electrode part is a non-light emitting part, the effective light emitting length of the lamp is shortened, resulting in a decrease in luminance uniformity on the display screen.

Therefore, in order to obtain a sufficient amount of light, the number of lamps must be increased or the potential difference between the electrodes of the lamp must be high. However, the cost increases according to the number of lamps and the glass tube pinholes are generated at the local part inside the electrode due to the high voltage.

In order to solve the above problems, an object of the present invention is to provide an external electrode fluorescent lamp that can improve the brightness and life of the lamp in the external electrode fluorescent lamp and a liquid crystal display device using the same.

In order to achieve the above technical problem, in an external electrode fluorescent lamp for supplying light to a liquid crystal panel, a fluorescent tube and a protective film is formed on the inner side of the glass tube and the outer electrode formed to surround the outer peripheral surface of both ends of the glass tube The glass tube includes SiO ₂ , B ₂ 0 ₃ , Al ₂ O ₃ , Na ₂ O, K ₂ O, Li ₂ O, CaO, MgO, BaO, SrO, ZnO and CeO ₂ , and B ₂ 0 ₃ is 0 to 5%, Na ₂ O is 5 to 12%, K ₂ O is 0 to 10%, BaO is 0 to 10% or 5 to 15%, CeO ₂ is 0.1 to 3% (a to b: and a composition ratio of more than a to less than b).

The external electrode fluorescent lamp according to the present invention has the following effects.

First, power consumption can be reduced by adjusting the components of the glass tube of the external electrode fluorescent lamp, and the luminance can be improved at the same current. In addition, it is possible to block unnecessary ultraviolet rays by further adding CeO ₂ material.

Second, in inserting the internal electrode to enlarge the area of the electrode, the dielectric coating layer of the internal electrode, except for the bead glass, which is bonded to the glass tube, is added with additives for improving the glass and the dielectric properties of the component is adjusted, power efficiency, luminous efficiency and lifetime Can be maximized. Additives for improving dielectric properties do not have to consider light transmittance like glass tubes, and can be sufficiently added within the limit of maintaining adhesion to metal lead lines to maximize the dielectric properties of the dielectric coating layer formed on the internal electrode.

Third, by forming the protective film spaced apart from the external electrode end portion, it is possible to reduce the phenomenon that the protective film is charged so that the wall charges are formed toward the center of the lamp from the external electrode. In addition, it is possible to solve problems such as power consumption increase and lighting delay occurring.

Fourth, when the external electrode is formed of any one of copper (Cu), copper alloy (Cu Alloy), iron (Fe), iron alloy (Fe Alloy), silver (Ag) excellent in thermal conductivity, the temperature rise of the local portion of the glass tube is increased. This can delay the pinhole phenomenon of the glass tube. As a result, an electrode opening phenomenon may be generated due to the pinhole phenomenon, thereby reducing the discharge efficiency and lifespan.

Hereinafter, an external electrode fluorescent lamp according to an embodiment of the present invention with reference to the accompanying drawings in detail as follows.

4 is a perspective view showing an external electrode fluorescent lamp 100 according to the first embodiment of the present invention.

Referring to FIG. 4, the external electrode fluorescent lamp 100 according to the present invention is formed to surround the outer circumferential surfaces of both ends of the glass tube 114 and the glass tube 114 in which the discharge space 122 is formed, thereby applying voltage to the glass tube. An external electrode 116 is formed for application.

The glass tube 114 is a transparent material having a high light transmittance, and a space for discharging is formed therein. The discharge space 122 inside the glass tube 114 is filled with discharge gas for light emission. As the discharge gas filled in the glass tube 114, an inert gas such as mercury (Hg), neon (Ne), krypdon (Kr), argon (Ar), xenon (Xe), or the like is used.

In addition, the inner wall of the glass tube 114 is formed with a protective layer 120 for protecting the glass tube 114 and a fluorescent layer 125 that is stimulated by the ultraviolet rays formed by the discharge to generate visible light. The passivation layer 120 is formed on the inner wall of the glass tube by wet coating with any one of Y ₂ O ₃ , ZnO, and Al ₂ O ₃ , followed by a calcination process.

 When the external electrode fluorescent lamp 100 is driven by applying an AC voltage to the external electrodes 116 at both ends of the lamp, an electric field is formed inside the lamp through the external electrodes 116. Accordingly, plasma is generated in the lamp internal space by the electric field. In this case, a conductive plasma environment is formed in the glass tube 114 by the generated plasma, and the generated ultraviolet rays excite the fluorescent layer 125 to irradiate visible light used as backlight light of the liquid crystal display device to the outside.

Here, each component composition ratio of the glass tube 114 is shown in Table 1. Table 1 shows the component composition amounts (wt%) of the materials of the glass tube 114. A condition refers to the component ratio of the glass tube (14 of FIG. 1) in the external electrode fluorescent lamp 10 of Figure 1, wherein the components of the glass tube (14 of Figure 1) are SiO ₂ , B ₂ 0 ₃ , Al ₂ O ₃ , ZnO, Na ₂ O, K ₂ O, Li ₂ O, which is an alkali metal oxide that is a Group 1 element, and CaO, MgO, BaO, SrO, which is a Group 2 element. In the composition ratio of each substance, the conditions a to b represent more than a to less than b.

The composition ratio of each material of the glass tube under A condition is 65 to 75% for SiO ₂ , 15 to 25% for B ₂ 0 ₃ , 0 to 5% for Al ₂ O ₃ , ₁ to 5% for Na ₂ O, and K ₂ O is 5 to 10%, Li ₂ O, CaO, MgO, BaO, SrO, and ZnO are each 0 to 5%.

The condition B corresponds to the first embodiment of the present invention, in which only the components and the composition amounts of the glass tube (14 of FIG. 1) are different from the external electrode fluorescent lamp (10 of FIG. 1) having the same structure as that of FIG. 1. Indicates. At this time, the components of the glass tube (14 in FIG. 1) are SiO ₂ , B ₂ 0 ₃ , Al ₂ O ₃ , Na ₂ O, K ₂ O, Li ₂ O, CaO, MgO, BaO, SrO, ZnO and CeO ₂ Is done. Among them, the composition ratio of each material is 65 to 75% for SiO ₂ , 0 to 5% for B ₂ 0 ₃ , 0 to 5% for Al ₂ O ₃ , 5 to 12% for Na ₂ O, and 0 to 0 for K ₂ O. 10%, Li ₂ O 0-10%, CaO 0-15%, MgO 0-15%, BaO 0-10%, SrO and ZnO 0-5%, CeO ₂ 0.1-3 %to be.

5A is a perspective view of the external electrode fluorescent lamp 100 according to the second embodiment of the present invention, and FIG. 5B is a perspective view of the external electrode fluorescent lamp 100 when voltage is applied.

In the external electrode fluorescent lamps shown in FIGS. 5A and 5B, descriptions of overlapping components will be omitted in comparison with the first embodiment.

5A and 5B, when the protective film 120 is formed, the electrical resistance of the protective film 120 is lowered due to the firing conditions, so that when the high voltage is applied, the protective film 120 is charged so that wall charges are formed from the external electrode 116. Since the lamp is formed toward the central portion, the protective film 120 is formed to be spaced 1 to 3 mm apart from the ends of the external electrodes 116 at each end of the glass tube 114.

As described above, since the protective film 120 is spaced apart from the end of the external electrode 116, the electrical resistance of the protective film 120 is lowered due to the firing conditions when the protective film 120 is formed at the end III of the external electrode as shown in FIG. 6A. When the high voltage is applied, the protection layer 120 is charged to reduce the phenomenon in which the wall charges are formed toward the center of the lamp from the external electrode 116. In addition, it is possible to solve problems such as power consumption increase and lighting delay occurring.

The fluorescent layer 125 is formed to cover both ends of the passivation layer 120 on the passivation layer 120.

6A, the protective layer 120 and the fluorescent layer 125 are enlarged in FIG. 6B.

In FIG. 6B, the passivation layer 120 is formed at a portion of the passivation layer 120 and the fluorescent layer 125 close to the outer electrode 116 and is spaced apart from the end portion of the outer electrode 116, thereby preventing the passivation layer 120 from being charged. As a result, mercury may be penetrated between the pores of the fluorescent layer 125 to solve the problem of shortening the life of the lamp. At this time, mercury (Hg) is moved toward the external electrode 116.

Here, the components of the glass tube 114 are formed under the C condition of Table 1. At this time, the components of the glass tube 114 are the same as the conditions B, the composition ratio of each material is 65 to 75% SiO ₂ , 0 to 5% B ₂ 0 ₃ , 0 to 5% Al ₂ O ₃ , Na ₂ 5-12% for O, 0-10% for K ₂ O, 0-5% for Li ₂ O, 0-5% for CaO, 5-15% for MgO, 0-10% for BaO, SrO and ZnO 0-5% and CeO ₂ each consist of 0.1 to 3%.

B ₂ O ₃ , Al ₂ O ₃ , K ₂ O, Li ₂ O, CaO, MgO, BaO, SrO, in the B and C conditions of Table 1 which are the components of the glass tube 114 in the first and second embodiments, component ratio of 0, the lower limit of ZnO is preferably 10 as a means that is not included at all ^- means ^6.

Here, B ₂ 0 ₃ of the components of the glass tube 114 is used to enhance the chemical resistance and thermal shock resistance of the glass, B ₂ 0 under the B and C conditions than the component ratio of B ₂ 0 ₃ in the A condition It can be seen that the component ratio of ₃ is reduced.

It can be seen that the alkali metal Na ₂ O, K ₂ O increased the component ratio in the B and C conditions compared to the A conditions. As such, when alkali metal is added to the glass tube 114, the dielectric constant may be increased, and electrical conductivity and light efficiency may be increased.

In addition, when materials such as MgO, CaO, BaO, SrO, ZnO, and Al ₂ O ₃ are added, the viscosity may be increased to improve the strength of the glass tube 114. However, when ZnO and Al ₂ O ₃ are added at 10% or more, the softening point and the working temperature of the glass become high, which causes a difficult manufacturing problem.

When an excessive amount of Na ₂ O material is added, the pinhole resistance of the glass tube 114 is lowered due to the generation of voids in the glass tube 114 and the decrease in density due to the precipitation of Na ions in the glass tube 114 of the external electrode 116. Therefore, Na ₂ O is added to less than 5 to 12% as shown in Table 1.

CeO ₂ has the effect of blocking unnecessary ultraviolet rays.

matter A B C SiO ₂ 65-75 65-75 65-75 B ₂ 0 ₃ 15-25 0 to 5 0 to 5 Al ₂ O ₃ 0 to 5 0 to 5 0 to 5 Na ₂ O 1 to 5 5 to 12 5 to 12 K ₂ O 5 to 10 0-10 0-10 Li ₂ O 0 to 5 0-10 0 to 5 CaO 0 to 5 0 to 5 0 to 5 MgO 0 to 5 0 to 5 0 to 5 BaO 0 to 5 0-10 5 to 15 SrO 0 to 5 0 to 5 0 to 5 ZnO 0 to 5 0 to 5 0 to 5 CeO ₂ - 0.1 to 3 0.1 to 3

As such, the external electrode fluorescent lamp 100 that controls the composition of each material of the glass tube 114 has the following effects.

As shown in Table 1, each power consumption of the external electrode fluorescent lamp 100 under conditions A to C according to the component composition of each material of the glass tube 114 is shown in FIG. 7.

It can be seen that the external electrode fluorescent lamps in the B and C conditions of the present invention have lower power consumption than the A condition representing the conventional external electrode fluorescent lamps. Specifically, in the fluorescent lamps B and C conditions of the present invention at a current of 7mA, it can be seen that the voltage of the lamp is reduced by 17% or more. In addition, for the same voltage, for example, at about 1900 Vrms, the current value is 5 mA under the A condition, the current value is 7 mA under the B and C conditions, and the corresponding luminance value is shown in FIG. 8. Referring to FIG. 8, it can be seen that the luminance is improved by 30% or more in the B and C conditions when the current value is 7 mA compared to the A condition when the current value is 5 mA.

In addition, as shown in FIG. 8, when the amount of light is compared at the same current value, the luminance of the external electrode fluorescent lamp 100 is 3% in the first and second embodiments of the present invention, i.e., in the B and C conditions. It can be seen that the increase.

When CeO ₂ is added to the glass tube 114 under the conditions B and C, it can be seen that ultraviolet rays are blocked in the 300-320 nm region in the ultraviolet region V as shown in FIGS. 9A and 9B. On the other hand, it can be seen that in the case of the A condition without CeO ₂ added, it does not block the ultraviolet rays.

As such, the outer electrode 116 formed to surround the outer circumferential surfaces of both ends of the glass tube 114 to apply a voltage to the glass tube 114 may have good thermal conductivity (Cu), copper alloy (Cu Alloy), and iron. It is formed of any one of (Fe), iron alloy (Fe Alloy), and silver (Ag). By forming the external electrode 116 of a metal having good thermal conductivity, pinholes of the fluorescent lamp can be prevented.

In general, the pinhole phenomenon in the external electrode fluorescent lamp occurs in two types. When the potential difference between the external electrodes is 2000 Vrms or more, pinholes are generated by corona discharge at the electrode end, or pinholes are concentrated at the place where the plasma density in the glass tube of the electrode is high. In the former case, when the potential difference between the lamp electrodes is less than 2000 Vrms, stable driving may be possible. In the latter case, the driving time of the lamp may accumulate as time passes and may not be avoided in the external electrode fluorescent lamp. Therefore, when the charge intensively collides with the localized glass tube, the temperature of the localized glass tube is raised, resulting in a pinhole phenomenon.

10A and 10B illustrate temperature variations according to materials of forming the external electrode 116 and each position of the external electrode 116. When the external electrode 116 is formed of a metal such as copper (Cu) and iron (Fe), the external electrode 116 may be formed of another metal, that is, a metal such as a nickel alloy or a tin alloy. It can be seen that the temperature deviation is not severe according to the position of the external electrode 116 as compared with the case of forming.

Accordingly, when the external electrode 116 is formed of any one of copper (Cu), copper alloy (Cu Alloy), iron (Fe), iron alloy (Fe alloy) and silver (Ag) as in the present invention, the glass tube It is possible to delay the pinhole phenomenon of the glass tube 114 by preventing the temperature rise at the localized portion. As a result, an electrode opening phenomenon may be generated due to the pinhole phenomenon, thereby reducing the discharge efficiency and lifespan.

11 is a perspective view illustrating the external electrode fluorescent lamp 100 according to the third embodiment of the present invention, and FIG. 12 is a perspective view of the external electrode fluorescent lamp 100 when voltage is applied.

In the external electrode fluorescent lamps shown in FIGS. 11 and 12, the description of the overlapping elements will be omitted in contrast to the first and second embodiments.

11 and 12, an inner electrode 140 formed inside the end of the glass tube 114 and a lead wire 130 drawn out of the glass tube 114 to connect power to the outer electrode 116 and the inner electrode are provided. Is formed.

The internal electrode is formed to enlarge an area of the electrode, and is formed of a metal lead line 140 connected to the lead wire 130 and a dielectric coating layer 142 surrounding the surface of the metal lead wire 140. Although not shown, the metal lead wire 140 may be formed by extending the lead wire 130.

Here, the bead glass 150 is formed on one side of the metal lead line 140 of the internal electrode to seal both ends of the glass tube 114.

The lead wires 130 and the metal lead wires 140 have similar thermal expansion coefficients to the bead glass 150 and thus have excellent bonding properties with the glass, and have excellent thermal conductivity such as nickel (Ni) and nickel (Ni) to minimize thermal stress. It consists of an alloy or iron (Fe) and nickel (Ni), copper (Cu) is coated with Dumet (Dumet). The dielectric coating layer 142 has a similar coefficient of linear expansion to the metal lead wire 140, and thus has excellent bonding properties, minimizes thermal stress, and may be formed of glass or alumina under conditions B and C of Table 1, which may improve dielectric properties. Barium titanate (BaTiO ₃ ) -based ferroelectric material is added to maximize the dielectric properties, wherein the weight ratio of the barium titanate (BaTiO ₃ ) -based material in the dielectric coating layer 142 is 35wt% to 45wt% or Owt%. Here, the value of 0 does not mean that it is not included at all, but preferably means 10 ⁻⁶ .

Here, barium titanate (BaTiO ₃₎ are ABO ₃ structure in which Fe Grove is Sky tree structure, a mixture of additives of the powder there is able to adjust the dielectric properties, BaZrO ₃ to control the additive rosseoneun phase transition temperature, SrTiO _3, BaSnO ₃ , CaSnO ₃ , PbTiO _3, and MgO, MgTiO ₃ , NiSnO ₃ , CaTiO ₃ , Bi ₂ (SnO ₃ ) _3, etc., which reduce the temperature characteristic of dielectric constant, are used.

Barium titanate (BaTiO ₃₎ If the mixing of the additive of the material in the base material, barium titanate scandium (Sr), calcium (Ca), magnesium (Mg) in place of barium (Ba) ions (BaTiO ₃₎ based Ions etc. are compounded and substituted. At this time, the molar ratio for the barium (Ba) ions is less than 1/4 maximum. In addition, zirconium (Zn), tin (Sn) ions, etc. are combined and replaced in the titanium (Ti) ion site, and the molar ratio for the titanium (Ti) ions is less than 1/3. Here, when the molar ratio for each ion is exceeded, the dielectric loss is increased, and the phase transition temperature is lowered, thereby reducing the power reduction efficiency in the use of the high temperature condition of the lamp.

As such, the dielectric coating layer of the inner electrode except for the bead glass 150 to be bonded to the glass tube 114 in inserting the inner electrode to enlarge the area of the electrode is added by adding an additive for improving the glass and the dielectric properties of the component is controlled Power efficiency, luminous efficiency and lifetime can be maximized. Additives for improving the dielectric properties do not have to consider light transmittance like the glass tube 114, the dielectric material of the dielectric coating layer 142 formed on the internal electrode by sufficiently added within the limit to maintain the bonding with the metal lead line 140 Can maximize the characteristics.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be apparent to those who have knowledge.

1 is a perspective view showing a conventional external electrode fluorescent lamp.

2 is a perspective view illustrating an external electrode fluorescent lamp when voltage is applied.

3A and 3B are views showing the region of FIG. 2.

4 is a perspective view showing an external electrode fluorescent lamp according to a first embodiment of the present invention.

5A is a perspective view illustrating an external electrode fluorescent lamp according to a second exemplary embodiment of the present invention.

5B is a perspective view illustrating an external electrode fluorescent lamp when voltage is applied.

6A and 6B are views showing region III of FIG. 5B.

FIG. 7 is a graph showing the power consumption of the external electrode fluorescent lamps in the A condition to the C condition according to the component composition of each material of the glass tube.

FIG. 8 is a graph showing the luminance of the external electrode fluorescent lamps in the A condition to the C condition according to the component composition of each material of the glass tube.

9A and 9B are graphs showing the ultraviolet ray blocking effect of the external electrode fluorescent lamps under the A condition to the C condition according to the component composition of each material of the glass tube.

10A and 10B are graphs illustrating pinhole resistance according to an external electrode forming material.

11 is a perspective view illustrating an external electrode fluorescent lamp according to a third embodiment of the present invention.

12 is a perspective view illustrating an external electrode fluorescent lamp when voltage is applied.

<Description of Symbols for Main Parts of Drawings>

100: external electrode fluorescent lamp 114: glass tube

116: external electrode 120: protective film

122: discharge space 125: fluorescent layer

130: lead wire 140: metal lead wire

142: dielectric coating layer 150: bead glass

Claims (10)

In the external electrode fluorescent lamp for supplying light to the liquid crystal panel, A glass tube encapsulated with a fluorescent layer and a protective film formed therein; It includes an external electrode formed to surround the outer peripheral surface of the both ends of the glass tube, The glass tube is composed of SiO ₂ , B ₂ 0 ₃ , Al ₂ O ₃ , Na ₂ O, K ₂ O, Li ₂ O, CaO, MgO, BaO, SrO, ZnO and CeO ₂ , B ₂ 0 ₃ is 0 -5%, Na ₂ O 5-12%, K ₂ O 0-10%, BaO 0-10% or 5-15%, CeO ₂ 0.1-3% (a-b: over a to b) Less than) composition ratio, And the protective layer is spaced apart from the end of the external electrode so that the protective layer and the external electrode do not overlap each other. The method of claim 1, The protective film is formed to be spaced apart by 1 ~ 3mm relative to the external electrode end, the protective film is an external electrode fluorescent lamp, characterized in that formed of any one material of Y ₂ O ₃ , ZnO, Al ₂ O ₃ . The method of claim 1, The external electrode fluorescent lamp, characterized in that formed of any one of copper, copper alloy, iron, iron alloy. The method of claim 1, An internal electrode formed inside the glass tube end; Further provided with a lead wire drawn out of the glass tube for the power connection of the external electrode and the internal electrode, The internal electrode includes a metal lead wire connected to the lead wire, and a dielectric coating layer surrounding the metal lead wire surface. An external electrode fluorescent lamp comprising a bead glass formed on one side of the metal lead line for sealing both ends of the glass tube. The method of claim 4, wherein The lead wire and the metal lead wire have a similar coefficient of linear expansion to the bead glass, and thus have excellent adhesion to glass, and have excellent thermal conductivity to minimize thermal stress, or an alloy of nickel (Ni) or nickel (Ni) or iron (Fe). And nickel (Ni) and an external electrode fluorescent lamp, characterized in that it is formed of any one of copper (Cu) coated Dumet (Dumet). The method of claim 4, wherein The dielectric coating layer is composed of SiO ₂ , B ₂ 0 ₃ , Al ₂ O ₃ , Na ₂ O, K ₂ O, Li ₂ O, CaO, MgO, BaO, SrO, ZnO and CeO ₂ , B ₂ 0 ₃ is 0 to 5%, Na ₂ O to 5 to 12%, K ₂ O to 0 to 10%, BaO to 0 to 10% or 5 to 15%, CeO ₂ to 0.1 to 3% (a to b: over a to An external electrode fluorescent lamp comprising a barium titanate (BaTiO ₃ ) -based material of a ferroelectric containing an additive in a glass or alumina material having a composition ratio of less than b). The method of claim 6, The weight ratio of the barium titanate (BaTiO ₃ ) -based material in the dielectric coating layer is an external electrode fluorescent lamp, characterized in that 35wt% to 45wt% or 0wt%. The method of claim 6, The additive _{BaZrO 3, SrTiO 3, BaSnO 3} , CaSnO 3, PbTiO 3, MgO, MgTiO 3, NiSnO 3, CaTiO 3, Bi 2 (SnO 3) an external electrode fluorescent lamp, characterized in that any one of _three. The method of claim 6, The molar ratio of the barium (Ba) ions in the barium titanate (BaTiO ₃ ) -based material is less than 1/4 maximum, the molar ratio of titanium (Ti) ions is less than 1/3 maximum Fluorescent lamps. A liquid crystal panel that implements an image, A liquid crystal display device comprising the external electrode fluorescent lamp according to any one of claims 1 to 9 for supplying light to the liquid crystal panel.

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