KR20080010612A - Fluorescent lamp and liquid crystal display having this - Google Patents

Abstract

A fluorescent lamp and a liquid crystal display having the same are provided to suppress cracks and damage of a glass tube by improving a sealing part of an electrode lead. A fluorescent lamp includes a glass tube(110), a pair of electrodes(131), and a pair of electrode leads. A fluorescent material(120) is coated on an inner surface of glass tube. An internal space of glass tube is filled with discharge gas. The electrodes are arranged at both ends of the glass tube. The electrode leads are coupled with both ends of the glass tube. A sealing part as a center region of the electrode lead has a large periphery in comparison with a connective part as both end regions of the electrode lead. The sealing part is inserted into the glass tube. The connective part of the electrode lead is a bar-shaped structure.

Description

Fluorescent lamp and liquid crystal display having the same {FLUORESCENT LAMP AND LIQUID CRYSTAL DISPLAY HAVING THIS}

1 is a cross-sectional view showing a fluorescent lamp according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view illustrating the first electrode part of FIG. 1. FIG.

3 is a front perspective view of the electrode lead of FIG.

4 is a cross-sectional view showing the dispersion structure of the force applied to the electrode lead in the fluorescent lamp according to the comparative example and the application example of the present invention.

5 is a cross-sectional view showing a fluorescent lamp according to a second embodiment of the present invention.

6 is a cross-sectional view illustrating the first electrode part of FIG. 5.

7 is a perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

8 is a perspective view of the lamp socket of FIG.

<Explanation of symbols for the main parts of the drawings>

110: glass tube 130: first electrode portion

131, 141: electrode 132, 142: electrode lead

140: second electrode portion 710: upper chassis

720: liquid crystal display panel 730: mold frame

740: optical sheet 750: backlight unit

751: fluorescent lamp 752: lamp socket

760: lower chassis

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp and a liquid crystal display device having the same. In particular, a fluorescent lamp capable of preventing breakage of a glass tube by improving an electrode structure, having excellent heat dissipation, and improving luminous efficiency and a liquid crystal display having the same Relates to a device.

Recently, flat panel displays such as liquid crystal displays (LCDs) and plasma display panels (PDPs) are rapidly developing in place of cathode ray tubes (CRTs).

Among the flat panel display devices, unlike the plasma display device, the liquid crystal display device does not emit light by itself, and thus requires a backlight unit to visually recognize the display contents.

The backlight unit includes at least one light source for providing image display light, and a fluorescent lamp is mainly used as the light source.

The fluorescent lamp includes a glass tube in which a phosphor is coated on an inner surface and a discharge gas is filled in an inner space, a pair of electrodes formed on both sides of the glass tube, and a pair of electrode leads coupled to the electrode. When the electric power is applied to the two electrodes through the two electrode leads, the discharge gas inside the glass tube is excited to emit the primary light, whereby the phosphor emits the secondary light and outputs white light.

Initially, a soldering method was mainly used to apply power to the fluorescent lamp. However, since assembly is poor and replacement and repair are difficult due to defects, a socket method is mainly used. At this time, the electrode lead of the fluorescent lamp is clamped by the clamp of the lamp socket to be gripped by elasticity to receive power.

However, in the socket system, the force applied to the fluorescent lamp during the mounting and detachment of the fluorescent lamp or by the impact during use is concentrated on the electrode lead having a lower strength than the lamp socket, and the force is coupled to the glass tube, in particular, the impact. Since the cracks are generated in the glass tubes by being transmitted to both ends of the glass, or in severe cases, the glass tubes may be broken. When a crack occurs in the glass tube, the discharge gas is leaked and the luminous efficiency is lowered. As the internal electrode is oxidized by the external air and the product life is shortened, the glass tube does not function as a normal light source.

Therefore, the present invention forms a central region of the electrode lead coupled to the glass tube with a larger circumference than both ends thereof, thereby preventing or breaking the glass tube by blocking or dispersing external force applied to the glass tube through the electrode lead, and thus preventing the electrode area. It is an object of the present invention to provide a new fluorescent lamp and a liquid crystal display device having the same, which can improve heat dissipation characteristics and luminous efficiency by increasing the power consumption.

A fluorescent lamp according to the present invention for achieving the above object is a glass tube in which a fluorescent material is applied to the inner surface, the discharge gas is filled in the inner space, a pair of electrodes disposed at both ends of the glass tube, and the glass tube It includes a pair of electrode leads coupled to both ends of the electrode lead is characterized in that the sealing portion of the central region is inserted into the glass tube and coupled to the larger area than the opposite end constituting the connecting portion is formed in a larger circumference.

It is preferable that the connection part of the electrode lead is formed in a rod shape, and the sealing part of the electrode lead is formed in a cylindrical shape.

The cross-sectional diameter (D) of the sealing portion of the electrode lead is preferably smaller than the inner diameter of both ends of the glass tube to be bonded thereto, and the body thickness (T) of the sealing portion of the electrode lead is to the sealing region of both ends of the glass tube coupled thereto. Smaller ones are preferable.

The connecting portion and the sealing portion of the electrode lead may be integrally formed using the same material. In this case, it is preferable that the connection part and the sealing part of the electrode lead are made of a conductive material having a similar coefficient of thermal expansion to the glass tube.

The connecting portion and the sealing portion of the electrode lead may be integrally formed using different materials. In this case, it is preferable that the connecting portion of the electrode lead is formed of a conductive material having good ductility, and the sealing portion of the electrode lead is formed of a conductive material having a similar coefficient of thermal expansion to the glass tube.

The sealing portion of the electrode lead is coupled to the glass tube by heat fusion of the glass tube, characterized in that to seal the inside.

A protective film may be further formed on the surface of the fluorescent material.

A liquid crystal display device according to the present invention for achieving the above object comprises a liquid crystal display panel for image display and a backlight unit for providing light for image display, the backlight unit, a fluorescent material is coated on the inner surface And a glass tube filled with discharge gas in an inner space, a pair of electrodes disposed at both ends of the glass tube, and a central region coupled to both ends of the glass tube and inserted into and coupled to the glass tube as compared to both ends of the glass tube. It characterized in that it comprises a fluorescent lamp having an electrode lead formed with a larger circumference of the sealing portion.

Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention;

However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention, and to those skilled in the art the scope of the invention. It is provided for complete information. Like reference numerals in the drawings refer to like elements.

First, a fluorescent lamp according to a first embodiment of the present invention will be described.

1 is a cross-sectional view showing a fluorescent lamp according to a first embodiment of the present invention, FIG. 2 is a partial cross-sectional view showing a first electrode of FIG. 1, and FIG. 3 is a front perspective view showing the electrode lead of FIG.

Referring to FIG. 1, the fluorescent lamp 100 includes a glass tube 110 in which a fluorescent material 120 is coated on an inner surface of the fluorescent lamp 100, and a discharge gas 150 is filled in an inner space, and both sides of the glass tube 110. The first and second electrode parts 130 and 140 are formed.

Glass tube 110 is formed in the form of a tube (tube) formed hollow along the central axis in the longitudinal direction. Such, the diameter and thickness of the glass tube 110 may be set in various ranges according to the application. For example, when ultra-thin is required, such as a fluorescent lamp for liquid crystal display devices, it is preferable to form a small diameter and thin thickness. In addition, the shape of the glass tube is not limited to the bar shape shown in FIG. 1 and may be modified into various shapes, for example, semicircular, circular, L-shaped, etc., depending on the use.

The inner space of the glass tube 110 is filled with a discharge gas 150 for generating primary light. The discharge gas 150 includes a rare gas such as argon, neon, xenon, or a mixed gas containing argon, neon, xenon, and the like and a predetermined amount of mercury, and the internal pressure is usually maintained at about 1/10 of atmospheric pressure. Of course, the discharge gas 150 is not limited thereto, and may be used as long as it is a discharge gas used in a conventional fluorescent lamp.

The inner surface of the glass tube 110 is coated with a fluorescent material 120 for generating secondary light. The fluorescent material 120 is preferably configured to emit white light by appropriately combining phosphors of three wavelength bands of red, green, and blue. Here, the red phosphor include Y ₂ O _3: Eu ³⁺ as a green phosphor LaPO _4: Ce ^{3 +,} a blue phosphor is BaMg ₂ Al ₁₆ O _27: Eu ³⁺ can be used. Of course, a combination of different phosphors is also possible.

First and second electrode portions 130 and 140 are inserted into and coupled to both ends of the glass tube 110, respectively, and both ends of the glass tube 110 are melted by local heating to form the first and second electrode portions 130 and 140. ) Is sealed, and the inside thereof is sealed. In this case, an area in which the glass tube 110 and the first and second electrode parts 130 and 140 are fused and sealed is defined as a sealing area below.

The first and second electrode parts 130 and 140 include a pair of electrodes 131 and 141 spaced apart from each other, and electrode leads 132 and 142 having one end coupled to the electrodes 131 and 141.

Referring to FIG. 2, the electrode 131 is formed in a cup shape, that is, a hollow hollow to maximize the electrode area by using a conductive metal plate, for example, a chromium (Cr) plate or a nickel (Ni) plate. It is preferable to form by processing into a cylindrical shape.

2 and 3, one end 132a of the electrode lead 132 is drawn out to the outside of the glass tube 110 and fitted to an external lamp socket (not shown) for power application, and the other end 132b. ) Is introduced into the glass tube 110 and coupled to the electrode 131. Both end regions of the electrode lead 132 are formed in a rod shape having a uniform circumference to form connecting portions 132a and 132b connected to the electrode 131 and the lamp socket (not shown), and the center region is more than the end region. It is formed in a cylindrical shape having a large circumference to form a sealing portion 132c coupled with the glass tube 110.

At this time, the cross section of the sealing portion 132c has a diameter (D) smaller than the inner diameter of the glass tube 110 so that it can be inserted into the glass tube 110, the body of the sealing portion 132c at both ends of the glass tube 110 It has a thickness T that is smaller than the sealing area of the glass tube 110 so that it can be sealed. For example, when the diameter of the glass tube 110 is about 3mm to 4mm, the cross-sectional diameter D of the sealing portion 132c is formed to be within about 3mm to 4mm, and the body thickness T is within about 0.5mm. It is effective to be formed.

The connection portions 132a and 132b and the sealing portion 132c of the electrode lead 132 are preferably formed integrally using the same material. For example, the connecting portions 132a and 132b and the sealing portion 132c have a coefficient of thermal expansion similar to that of the glass tube 110 and may be formed of a material having high strength, for example, tungsten (W). Of course, it is also possible to use conventional electrode materials such as chromium (Cr), lead (Pb), copper (Cu) and the like.

4 is a cross-sectional view showing the dispersion structure of the force applied to the electrode lead in the fluorescent lamp according to the comparative example and the application example of the present invention, (a) is a conventional fluorescent lamp according to the comparative example to the mounting or detachment of the lamp socket (B) shows the dispersion of the force applied to the electrode lead when mounting or detaching the fluorescent lamp of the present embodiment according to the present application to the lamp socket.

The force exerted on the electrode lead 432/132 during the mounting or detachment of the fluorescent lamp 400/100 to the lamp socket, that is, the pressing force F ₁ , is the electrode lead 432/132 and the glass tube 410 /. The glass tube 410/110 is transmitted to the bonding region of the 110 and a force repulsing thereto, that is, a repulsive force F ₂ is applied.

Referring to (a), since the entire area of the electrode lead 432 of the fluorescent lamp 400 according to the present comparative example is formed to be thin in a uniform thickness, the force F ₁ in the vertical direction applied to the electrode lead 432. As a result, the force F ₂ in the vertical direction is applied to the glass tube 410. On the other hand, referring to (b), the electrode leads 132 of the fluorescent lamp 100 according to the present application are thinly formed at both ends of the connecting portions 132a and 132b, and the central region forming the sealing portion 132c. Since is formed thick, the vertical force (F ₁ ) applied to the electrode lead 132 is converted to the horizontal direction for the sealing portion 132c and the glass tube 110 is applied to the horizontal force (F ₂ ).

Typically, the glass tube 410/110 is vulnerable to breakage due to the vertical direction rather than the force in the longitudinal direction, that is, the horizontal direction due to the structural features are formed in a thin thickness. Therefore, the fluorescent lamp of (b) in which the force acts in the horizontal direction is more effective in preventing damage due to the impact than the fluorescent lamp of (a) in which the force acts in the vertical direction of the glass tube 410/110. Further, in the fluorescent lamp of (b), since the sealing portion 132c having a relatively large circumference contacts the glass tube 110, the contact area is increased, which is more advantageous for the dispersion of force.

As described above, in the fluorescent lamp according to the present embodiment, since the external force is dispersed and stress is not concentrated on a specific portion of the glass tube, cracks and breakage of the glass tube are prevented. In addition, the sealing part of the electrode lead is in contact with the inside and the outside of the glass tube to serve as a heat sink and at the same time serves as an auxiliary electrode to improve the heat radiation characteristics and luminous efficiency.

Next, a fluorescent lamp according to a second embodiment of the present invention will be described. At this time, the description overlapping with the configuration and effect of the fluorescent lamp according to the first embodiment described above will be omitted or briefly described.

5 is a cross-sectional view illustrating a fluorescent lamp according to a second embodiment of the present invention, and FIG. 6 is a cross-sectional view illustrating a first electrode unit of FIG. 5.

Referring to FIG. 5, the fluorescent lamp 500 is formed on both sides of the glass tube 510 in which the fluorescent material 520 is applied to an inner surface of the fluorescent lamp 500, and the discharge gas 560 is filled in the inner space. First and second electrode parts 540 and 550 are included.

A protective film 530 is formed on the inner surface of the glass tube 510 to protect the fluorescent material 520 described above. The protective film 530 serves to protect the fluorescent material 520 from being damaged from heat and arc generated when the discharge gas 560 emits light.

The first and second electrode parts 540 and 550 include electrodes 541 and 551 formed in a plate shape and electrode leads 542 and 552 having one end coupled to the electrodes 541 and 551. Of course, the electrode 541 may be formed in a cup shape to maximize the electrode area as in the above-described embodiment, and may be transformed into various other shapes.

Referring to FIG. 6, both end regions of the electrode lead 542 are formed in a rod shape having a uniform circumference to form connecting portions 542a and 542b connected to the electrode 541 and the lamp socket, and the center region is formed at both end regions. It is formed in a cylindrical shape having a larger circumference to form a sealing portion 542c coupled to the glass tube 510.

The electrode lead 542 includes rod-shaped metal members 542a and 542b and a sealing member 542c in which a hollow is formed in a central axis of the cylindrical body, and the sealing members are provided in the metal members 542a and 542b. It is preferable to insert 542c and fix it to form an integrated body. In this case, the metal members 542a and 542b may be formed of a material having high electrical conductivity and good ductility such as lead (Pb) or copper (Cu) to absorb the external pressing force. The sealing member 542c has a coefficient of thermal expansion similar to that of the glass tube 510 and is preferably formed of a material having high strength, for example, tungsten (W).

Meanwhile, in the above-described first and second embodiments, the connecting portions 132a, 132b / 542a, 542b of the electrode leads are formed in a rod shape and have a uniform thickness and a circular cross section, but the present invention is not limited thereto. The thickness may be increased or decreased, for example, from one side to the other side, and the cross section may be changed into, for example, a triangle or a square.

In addition, in the above-described first and second embodiments, the sealing portions 132c / 542c of the electrode leads are formed in a cylindrical shape to have a uniform thickness and a circular cross section, but the thickness is not limited thereto. For example, the thickness increases from the periphery to the center, and may be formed to have a symmetrical structure, and the cross section may be appropriately modified according to the inner diameter shape of the glass tube.

Next, a liquid crystal display according to an exemplary embodiment of the present invention will be described.

FIG. 7 is a perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 8 is a perspective view illustrating the lamp socket of FIG. 7.

Referring to FIG. 7, the liquid crystal display includes a liquid crystal display panel 720, an optical sheet 740 disposed under the liquid crystal display panel 720, a backlight unit 750, and an upper chassis 710 for storing them. And a control printed circuit board (control PCB) (not shown) mounted on the bottom of the lower chassis 760 and the lower chassis 760.

A plurality of pixels are formed in the liquid crystal display panel 720 to display an image. Although not shown, the liquid crystal display panel 720 includes a liquid crystal layer interposed between the upper substrate and the lower substrate disposed to face each other.

The upper substrate includes a plurality of red (R), green (G), and blue (B) color filters that implement color by coloring light incident in the pixel region, and a plurality of black matrices that block light incident in the non-pixel region. Is a transparent substrate arranged in a lattice structure. A common electrode formed of a transmissive conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) is formed on an opposite surface of the upper substrate.

The lower substrate is a transparent substrate in which a plurality of thin film transistors (TFTs), which are switching elements, are arranged in a lattice structure. A data line is connected to a source electrode of the thin film transistors, a gate line is connected to a gate electrode, and a pixel electrode formed of a light transmissive conductive material such as ITO or IZO is connected to a drain electrode.

The data PCB 721 and the gate PCB 722 are connected to the liquid crystal display panel 720, and the data PCB 721 is connected to a control PCB (not shown) through a flexible printed circuit (FPC) (not shown). Is electrically connected to) to receive a predetermined signal. In this case, the data PCB 721 is electrically connected to a data line formed in the liquid crystal display panel 720 to transmit a gray voltage to each pixel, and the gate PCB 722 is electrically connected to a gate line, thereby providing each pixel. Transfers the gate on / off voltage and the like. Of course, the data PCB 721 and the gate PCB 722 may be integrated into one.

The optical sheet 740 is disposed on the front surface of the backlight unit 750 to uniform the luminance distribution of light incident on the liquid crystal display panel 720. The optical sheet 740 preferably includes a diffusion sheet 741, a first prism sheet 742, and a second prism sheet 743 from below, and the luminance is laminated on the second prism sheet 743. It is preferred to include a reinforcing sheet 744. Of course, some of the optical sheet 740 may be omitted, and an optical sheet having other optical properties may be added.

The diffusion sheet 741 scatters the light incident from the backlight unit 750 in the direction of the liquid crystal display panel 720 and diffuses the light.

The first and second prism sheets 742 and 743 each have a prism pattern formed in a direction crossing each other on an upper surface thereof so that light diffused from the diffusion sheet 741 is perpendicular to a rear surface of the liquid crystal display panel 720. Serves to condense.

The brightness enhancement sheet 744 reduces the loss of light emitted from the first and second prism sheets 742 and 743, thereby increasing brightness and providing a wide viewing angle characteristic. The brightness enhancement sheet 744 may be a dual brightness enhancement film (DBEF) sheet or a diffuse reflective polarizer film (DRPF) sheet. The DBEF sheet or the DRPF sheet is a thin film type reflective polarizing sheet, and prevents light from being absorbed by the lower polarizing plate of the liquid crystal display panel 720. The luminance is increased by allowing the absorbed and lost light to be used again.

The backlight unit 750 includes at least one light source 751, a lamp socket 752 that grips the light source 751, and a backlight driver (not shown) electrically connected to the lamp socket 752. .

As the light source 751, it is preferable to use the fluorescent lamps according to the first and second embodiments described above. The fluorescent lamp includes a glass tube coated with a fluorescent material on an inner surface thereof, first and second electrode parts formed on both sides of the glass tube, and a discharge gas filled in the glass tube. In particular, both end regions of the electrode leads coupled to the electrodes of the first and second electrode portions to apply driving power are formed in a rod shape having a uniform circumference to form a connection portion connected to the electrode and the lamp socket, and the center region is provided at both ends. It is formed in a cylindrical shape having a larger perimeter than the area to form a sealing portion that is combined with the glass tube.

Referring to FIG. 8, the lamp socket 752 includes a clamp 752a that grips the electrode lead of the fluorescent lamp 751 due to elasticity, a base 752b on which the clamp 752a is disposed, and a wiring to which power is applied. (752c).

The clamp 752a is processed into a double-sided curved surface facing the conductive plate, and grips the electrode lead of the fluorescent lamp 751 sandwiched therebetween by elastic force. The pair of clamps 752a are arranged on both sides of the fluorescent lamp 751 to form a pair, and are provided in the same number as the fluorescent lamp 752a used.

The backlight driver (not shown) provides driving power to the light source 751. The backlight light source driver includes a substrate on which a predetermined circuit pattern is formed, and an inverter and a transformer mounted on the substrate. The current converted into alternating current through the inverter is stepped up or down to be suitable for driving the light source 751 while passing through the transformer, and then transferred to the light source 751. Of course, the backlight driver may be integrally formed with a control PCB (not shown) and mounted on the rear surface of the lower chassis 760.

A timing control circuit, a voltage drop circuit, an AD converting circuit, and the like are formed in the control PCB (not shown), so that the image signal and the supply power applied from the outside are used to drive the liquid crystal display panel 720 and the light source driver. Is converted into the data PCB 721, the gate PCB 722, and the backlight driver. Various electrical signals generated in the control PCB are transmitted to the data PCB 721 through an FPC (not shown). Of course, the FPC may be connected to the gate PCB 722 and may be connected to both sides of the gate PCB 721 and the data PCB 722.

In the storage space provided by the combination of the upper chassis 710 and the lower chassis 760, a mold frame 730 which protects the edge of the liquid crystal display panel 720 which is vulnerable to impact and fixes the mounting position of the optical sheet 740. ) Is accepted. Of course, the mold frame 730 may be omitted as necessary.

The upper chassis 710 is formed in a rectangular frame shape including a planar portion in which an opening region for exposing the pixel region of the liquid crystal display panel 720 to the outside and a sidewall portion extending from an edge of the planar portion.

Lower chassis 760 includes a flat bottom surface and sidewall portions extending from edges of the bottom surface. The bottom and sidewalls of the lower chassis 760 may further include a reflective layer formed of silver (Ag), aluminum (Al), or the like, in order to increase light utilization, and a separate reflective plate may be additionally disposed. have.

As described above, the above embodiments are disclosed for purposes of illustration, and those skilled in the art will appreciate that various modifications, improvements, substitutions, and additions may be made without departing from the spirit of the present invention. Accordingly, the technical scope of the present invention is defined by the appended claims.

As described above, in the present invention, since the external force applied to the glass tube is blocked or dispersed by the sealing portion of the electrode lead, cracks and breakage of the glass tube are prevented.

In addition, according to the present invention, since the sealing portion of the electrode lead is in contact with the inside and the outside of the glass tube, the heat generated therein can be quickly released to the outside, thereby improving heat dissipation characteristics.

In addition, in the present invention, since the sealing part of the electrode lead serves as an auxiliary electrode together with the original electrode, the luminous efficiency is improved.

Claims (16)

A glass tube in which a fluorescent substance is applied to the inner surface and a discharge gas is filled in the inner space; A pair of electrodes disposed at both ends of the glass tube, A pair of electrode leads coupled to both ends of the glass tube, Wherein the electrode lead is a fluorescent lamp, characterized in that the sealing portion of the central region is inserted into the glass tube and coupled to the larger area than the both ends forming the connection portion. The method according to claim 1, The connecting part of the electrode lead is formed in the shape of a rod fluorescent lamp. The method according to claim 1, And a sealing portion of the electrode lead is formed in a cylindrical shape. The method according to claim 3, The cross-sectional diameter (D) of the sealing portion of the electrode lead is smaller than the diameter of the inner diameter of the both ends of the glass tube coupled to the fluorescent lamp. The method according to claim 3, The body thickness (T) of the sealing portion of the electrode lead is smaller than the sealing area of the both ends of the glass tube coupled to the fluorescent lamp. The method according to claim 1, The connecting portion and the sealing portion of the electrode lead is formed integrally using the same material. The method according to claim 6, And the connecting portion and the sealing portion of the electrode lead are formed of a conductive material having a similar coefficient of thermal expansion to a glass tube. The method according to claim 1, The connecting portion and the sealing portion of the electrode lead is formed integrally using different materials. The method according to claim 8, And the connecting portion of the electrode lead is formed of a conductive material having good ductility, and the sealing portion of the electrode lead is formed of a conductive material having a similar coefficient of thermal expansion to a glass tube. The method according to claim 1, And a sealing part of the electrode lead is coupled to the glass tube by heat fusion of the glass tube to seal the inside thereof. The method according to claim 1, Fluorescent lamp, characterized in that the protective film is formed on the surface of the fluorescent material. A liquid crystal display device comprising a liquid crystal display panel for image display and a backlight unit for providing light for image display. The backlight unit, A glass tube in which a fluorescent substance is applied to the inner surface and a discharge gas is filled in the inner space; A pair of electrodes disposed at both ends of the glass tube, And a fluorescent lamp coupled to both ends of the glass tube and having an electrode lead formed at a larger circumference of a sealing portion of a central region inserted into and coupled to the glass tube as compared to both end regions forming a connection portion. . The method according to claim 12, The connecting portion of the electrode lead is formed in the shape of a rod liquid crystal display device. The method according to claim 12, And the sealing part of the electrode lead is formed in a cylindrical shape. The method according to claim 12, The connecting portion and the sealing portion of the electrode lead are formed integrally using the same material. The method according to claim 12, The connecting portion and the sealing portion of the electrode lead are formed integrally using different materials.

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