KR20090041785A - Liquid crystal display device and fabricating method thereof - Google Patents

Abstract

A liquid crystal display device and a fabricating method thereof are provided to remove an expensive phosphor bronze tube during an external electrode forming process of a fluorescent lamp, thereby simplifying the entire process and reducing manufacturing costs. A backlight device comprises a lamp(120). The lamp comprises an external electrode(122) and a glass tube(121). A conductive material is formed in both external sides of the glass tube. A lamp holder(110) is comprised of the first common electrode line(113), the second common electrode line(115) and a gripper-type connecting unit(111). The first common electrode line is in parallel with the second common electrode line. A connecting unit connects the first common electrode line and the second common electrode line. The connecting unit surrounds the external electrode of the lamp. The lamp holder comprises a stopper(117). The stopper is vertically formed in the end of the second common electrode line. Accordingly, the stopper prevents the flow of the connected lamp. A diffusion plate(130) and a diffusion sheet(131) are formed in an upper side of the lamp. The diffusion plate and the diffusion sheet uniformly diffuse light provided from the lamp.

Description

Liquid crystal display and its manufacturing method {LIQUID CRYSTAL DISPLAY DEVICE AND FABRICATING METHOD THEREOF}

The present invention relates to a liquid crystal display device and a method of manufacturing the same, and more particularly, a fluorescent material formed of an external electrode through a separate heat treatment of a metal paste formed by mixing and forming a material to enable uniformity and thickness control of an electrode. A liquid crystal display equipped with a lamp and a method of manufacturing the same.

Recently, as the technology of the information and communication field develops, the importance of the display industry for displaying desired information is also rapidly increasing. Among them, it will be a flat panel display. These flat panel displays have a wider variety of applications, from computer monitors to aircraft and spacecraft.

Currently produced or developed flat panel displays include liquid crystal displays (LCDs), field emission displays (FEDs), plasma display panels (PDPs), and most importantly, to become ideal flat panel displays. Light weight, high brightness, high efficiency, high resolution, high-speed response characteristics, low driving voltage, low power consumption, low cost (low cost) and natural colors are required.

Among them, the liquid crystal display device is particularly popular because of its durability and easy portability, as well as consumer desires. A liquid crystal display device is an image display device using optically anisotropic characteristics of liquid crystals. When light is irradiated onto a liquid crystal having polarization characteristics according to an applied state of the liquid crystal, the amount of light passing through the liquid crystal is adjusted according to the alignment state of the liquid crystal according to the applied voltage. To represent an image.

Its configuration is simply a liquid crystal panel including an array substrate on which a thin film transistor is formed, a color filter substrate on which a color filter is formed, and a liquid crystal formed between two substrates, and a signal provided around the liquid crystal panel to control a signal applied to the liquid crystal panel. It consists of a drive circuit. In addition, the liquid crystal display device requires a separate backlight device that provides light from the lower part of the liquid crystal panel because it is not a self-luminous element that can emit light by itself. The size is gradually increasing.

For example, as a backlight device, a direct type backlight device, in which lamps are disposed in parallel to each other on a rear surface of the liquid crystal panel and directly provides light to the liquid crystal panel, is widely used. However, such a direct backlight device requires a large number of lamps for high brightness and uniformity of brightness, and thus, EEFLs have been developed that can drive a plurality of lamps in parallel with one inverter for cost reduction and driving stability.

Next, the EEFL will be described with reference to the accompanying drawings.

1A is a cross-sectional view illustrating a schematic structure of an EEFL, and FIG. 1B is an equivalent circuit diagram of FIG. 1A.

As shown in FIG. 1A, the EEFL includes a glass tube 21 sealed with a mixed gas and mercury vapor therein, and an AC voltage 23 applied from a power source to surround the outer edges of both ends of the outside of the glass tube 21. The first external electrode 35 and the second external electrode 37 are included. Here, when high voltage is applied to the first external electrode 35 and the second external electrode 37, induction electricity is generated on the inner wall of the glass tube 21 to emit visible light.

In addition, referring to FIG. 1B, the EEFL includes the first capacitor C1 and the mercury vapor between the first external electrode 35 and the mercury vapor between the two electrodes, the resistance R, The second external electrode 37 having the glass tube 21 interposed therebetween and the mercury vapor may be understood as the second capacitor C2.

In this case, in order to charge mercury vapor present in the glass tube 21, high voltages having different phases are applied to the first external electrode 35 and the second external electrode 37, respectively. Therefore, the EEFL is applied with a high frequency high voltage to the first external electrode 35 and the second external electrode 37 to reduce the capacitive voltage drop using the first capacitor C1 and the second capacitor C2. .

Of course, in order to apply a high frequency to the EEFL, a variable circuit for varying the power frequency and a resonant circuit or filter for making a high voltage of a sine wave or a square wave from an AC power source may be additionally provided.

FIG. 2 is a diagram illustrating a method of forming an external electrode of FIG. 1A.

As shown in FIG. 2, the phosphor 50 is coated on the inner wall, and the phosphor bronze tube 40 is inserted into both sides of the glass tube 21 containing the mixed gas and the mercury vapor therein, and then the liquid state as a main component. When dipping into a container containing Pb, lead penetrates into the gap between the glass tube 21 and the phosphor bronze tube 40, thereby forming an external electrode.

As lead is now restricted by environmental regulations, lead-free lead is mainly used. Lead-free lead is expensive, and phosphor bronze tubes are also very expensive, leading to an increase in the cost of external electrode fluorescent lamps. The manufacturing cost of the liquid crystal display device is also increasing.

In addition, the phosphor bronze tube is a phenomenon that the phosphor bronze tube is pulled out of the glass tube when the coefficient of thermal expansion is different from the glass tube is accompanied by the hassle of work.

The present invention has been made to solve the above problems, and an object thereof is to provide a liquid crystal display device having a fluorescent lamp formed with an external electrode through a metal paste capable of adjusting the uniformity and thickness of the electrode, and a manufacturing method thereof. Is in.

A liquid crystal display device for achieving the above object is a liquid crystal panel; And an external electrode configured to provide light to the liquid crystal panel, wherein an external electrode formed by mixing a conductive material and a glass frit is formed on both outer surfaces of both sides of a long axis of a sealed glass tube in which a fluorescent material is formed on an inner wall and a mixed gas is contained. Characterized in that comprises a.

In addition, a method of manufacturing a liquid crystal display device may include forming a metal paste by mixing a conductive material, an organic binder, a solvent, and a glass frit; Adsorbing the metal paste on both outer surfaces in the longitudinal direction by dipping a sealed glass tube in which a fluorescent material is formed on an inner wall of the metal paste and containing a mixed gas; Heat-treating the metal paste adsorbed on both outer surfaces of the sealed glass tube; And disposing a sealed glass tube formed by heat treatment of the metal paste under the liquid crystal panel.

As a result of the above configuration, the present invention can remove the expensive phosphor bronze tube from the external electrode type of the fluorescent lamp, and further simplify the overall process, thereby reducing the manufacturing cost, and also the efficiency of the operation This increases the yield of the liquid crystal display device.

Hereinafter, a configuration of the liquid crystal display device and a method of forming an external electrode of a fluorescent lamp will be described in detail with reference to the accompanying drawings.

3 is a configuration diagram of a liquid crystal display having a fluorescent lamp having an external electrode made of a glass frit and a conductive material according to the present invention.

As shown in FIG. 3, the liquid crystal display according to the present invention includes a liquid crystal panel 150 in which an image is implemented and a backlight device 110, 120, 130 provided under the liquid crystal panel 150 to provide light. , 131, wherein the backlight devices 110, 120, 130, and 131 are formed of a conductive material in which glass frit is mixed on both outer surfaces of the sealed glass tube 121 in the major axis direction of the sealed glass tube 121. It comprises a lamp 120 forming a. Here, the glass frit is a material containing lead oxide (PbO), zinc oxide (ZnO), silicon oxide (SiO ₂ ), barium oxide (BaO) powder, a filler, and the like.

First, a reflector (not shown) is attached on the lower cover 100 made of aluminum (Al) or an electrogalvanized steel sheet (EGI) to reflect light from the plurality of lamps 120 which are light sources to the front. have. In this case, the material of the reflector is a white polyester film or a film coated with metal (Ag, Al). The reflectance of the visible light in the reflector is about 90 to 97%, and the thicker the coated film, the higher the reflectance. do.

And both sides of the lower cover 100 is provided with a lamp holder 110 to which the lamp 120 is fastened. Of course, the lamp holder 110 is for applying a voltage to the electrode portion of the lamp 120. For example, the lamp holder 110 according to the present invention includes first and second common electrode lines 113 and 115 formed side by side at a predetermined interval, and the first and second common electrodes as shown in the drawing. The lines 113 and 115 may be connected to each other to form a gripper type fastening part 111 surrounding the external electrode 122 of the lamp 120. In addition, the lamp holder 110 includes a stopper 117 formed perpendicularly to the end of the second common electrode line 115 to prevent the flow of the fastened lamp 120.

Of course, the lamp 120 fastened to the lamp holder 110 includes an inert gas such as argon (Ar) or neon (Ne), a small amount of mercury vapor, and a glass tube sealed by applying a fluorescent material to the inner wall thereof ( 121 and an external electrode formed with a predetermined width on the outer surface of the rounded portions (or vertical surfaces of both ends of the glass tube 121 vertically) at both ends of the long axis direction of the glass tube 121 ( 122). At this time, the external electrode 122 is made of a conductive material mixed with a glass frit to increase the adhesion (or bonding force) with the glass tube 121, wherein the conductive material is platinum (Pt), silver (Ag), lead (Pb) ), Or a conductive material such as aluminum (Al) and copper (Cu), or a mixture of at least two of the conductive materials.

As described above, when the same AC voltage in the range of approximately 1500 to 2000V is applied to the external electrode 122 having a predetermined width on both sides of the lamp 120, an electric field is formed by both external electrodes 122 of the lamp 120. The electrons are rapidly concentrated on the inner wall of the glass tube 121 of the lamp 120 in which the external electrode 122 is formed by the electric field, and the electrons collide with the mercury atoms or molecules to form secondary electrons. Excite the atom. In addition, the excited mercury atoms emit ultraviolet rays while stabilizing, ultraviolet rays are absorbed by the fluorescent material formed on the inner wall of the lamp 120 to excite the fluorescent material, and visible light is emitted by stabilization of the excited fluorescent material.

The upper side of the lamp 120 is provided with light scattering means such as a diffusion plate 130 and the diffusion sheet 131 to uniformly diffuse the light provided from the lamp 120. Of course, in addition to this, a prism sheet for improving the brightness of the light transmitted through the diffusion plate 130 and the diffusion sheet 131, and a protective sheet for protecting the prism sheet may be loaded.

In addition, although not shown in the drawing, the main support (not shown) including the backlight devices 110, 120, 130, and 131 including the light scattering means is fastened to maintain the balance of the overall power of the liquid crystal display device. Doing.

The liquid crystal panel 150 including the driving circuit unit is mounted on the main support, such as a gate and a data printed circuit board (PCB). In this case, the gate and the data PCB are electrically connected to the liquid crystal panel 150 through a tape carrier package (TCP) method.

Here, the liquid crystal panel 150 includes a TFT array substrate disposed below, a color filter substrate positioned above the array substrate, and a liquid crystal layer formed by being injected between the two substrates. TFTs that perform a switching role are formed on the TFT array substrate in a matrix form, and a gate line is connected to the gate electrode of each TFT. The data line is connected to the source electrode, and the pixel electrode is formed on the drain electrode. The color filter substrate is provided with red (R), green (G), and blue (B) color filters for displaying an image, and a common electrode is formed on the color filter substrate.

In addition, the upper cover 160 surrounds the four surface edge regions of the liquid crystal panel 150 and is fastened to the lower cover 100.

4 is a view illustrating a process of forming an external electrode of the fluorescent lamp of FIG. 3.

As shown in FIG. 4, the external electrode forming process of the lamp according to the present invention forms a liquid metal paste formed by mixing a conductive material, a glass frit, an organic binder, a solvent, a plasticizer and a dispersant, and then the metal paste. Dipping the both ends of the long-axis direction of the glass tube in a sealed state by applying an inert gas such as argon (Ar) or neon (Ne) and a small amount of mercury vapor to the inner wall of the container containing After adsorb | sucking a metal paste, it heat-processes at high temperature.

Here, the conductive material, the glass frit, the solvent, and the organic binder may be mixed with each other to form a minimum metal paste. In this case, a solvent having a low boiling point may be used to increase the drying speed of the metal paste. have. In addition, the metal paste may be added with a plasticizer and a surfactant (or surface active agent) as a kind of additive to improve its properties. These increase the dispersibility of powder-forming particles such as conductive materials and glass frit and facilitate workability. For example, plasticizers will improve the flowability, ie mixing, of the metal paste by breaking the intermolecular linkages of the organic binder and weakening the attraction forces between the molecules.

First, the conductive material is made of a material such as platinum (Pt), silver (Ag), lead (Pb), aluminum (Al) and copper (Cu), or a material formed by mixing at least two of the above materials. As a total content may be formed in the range of 40 to 80%, preferably 60 to 80% is appropriate.

Glass frit consists of fine glass particles in powder form including lead oxide (PbO), zinc oxide (ZnO), silicon oxide (SiO ₂ ), barium oxide (BaO) powder, filler, etc. It acts as an adhesive, which has a bonding force between the conductive materials and, in addition, a bonding force between the conductive material and the sealed glass tube. The preferred content of the external electrode is preferably 10 to 50%, more preferably 20 to 40%.

In addition, the organic binder is an organic polymer resin of any one of cellulose, acrylic, epoxy, and urethane, and its total content is suitable in the range of 2 to 15%, and more preferably 3 to 10% in the present invention. Such an organic binder allows the surfactant to be viscous to determine the thickness of the metal paste or conductive material formed on the outer surface of the glass tube, which is directly related to the resistance of the external electrode. Therefore, the higher the viscosity, which is the sticky degree of the metal paste, the thicker the metal paste will be formed on the outer surface of the glass tube, resulting in a smaller resistance of the conductive material.

In addition, the conductive material contains a solvent to form a metal paste. As mentioned above, the solvent may improve productivity by using a low boiling point material to increase the drying speed of the metal paste. have. As such a solvent, any one of isopropyl alcohol (IPA), EA, methyl ethyl ketone (MEK) and acetone is usually used. The total content is 10 to 50%, and in the present invention, the solvent is 15 to 30%. Occupy.

On the other hand, the plasticizer (可塑 劑) is mentioned as briefly above, as a softening agent to improve the compatibility between the surfactant, the organic binder and the conductive material by reducing the intermolecular attraction by breaking the intermolecular link of the organic binder, The total content of the metal paste is preferably in the range of 0.1 to 3%, and more preferably in the range of 0.2 to 0.5%.

In addition, the surfactant is a kind of particle dispersant, which reduces the surface tension with the glass tube so that the metal paste can be easily adsorbed to a predetermined area of the outer surface of the glass tube, and is composed of particles such as powder conductive material and glass frit. In addition, the metal paste formed on the outside surface of the glass tube is also aggregated with each other to prevent the adsorption of the dispersibility. Here, the content of the metal paste is in the range of 0.1 to 3% is suitable, in the present invention is formed with a composition ratio of 0.2 to 1%.

Subsequently, a metal paste containing a conductive material, a glass frit, an organic binder, and a solvent formed at an optimum composition ratio in consideration of viscosity, flowability, and dryness as described above is contained in a container, and the glass tube has a long axis direction sealed in the container. Both ends are dipped to adsorb a metal paste having a uniform thickness in a predetermined region.

Subsequently, when the metal paste adsorbed on the outer surface of the glass tube is heat treated at a high temperature of 200 to 400 ° C., the solvent is evaporated, the organic binder is exhausted, and the conductive material is adsorbed onto the glass tube by the glass frit. Form an electrode.

At this time, the plasticizer and the surfactant may be burned during the heat treatment, but a part thereof may be included in the external electrode due to remaining.

1A is a cross-sectional view illustrating a schematic structure of an EEFL

FIG. 1B is an equivalent circuit diagram of FIG. 1A

2 is a view illustrating a method of forming an external electrode of FIG. 1A;

3 is a configuration diagram of a liquid crystal display device having a fluorescent lamp having an external electrode made of a glass frit and a conductive material according to the present invention;

4 is a view illustrating a process of forming an external electrode of the fluorescent lamp of FIG.

Claims (17)

A liquid crystal panel; And A liquid crystal display device comprising a lamp that provides light to the liquid crystal panel and includes a sealed glass tube and an external electrode formed by mixing a conductive material and glass frit on both outer surfaces of the glass tube in the longitudinal direction of the glass tube. . The method of claim 1, wherein the conductive material is formed of any one of platinum (Pt), silver (Ag), lead (Pb), aluminum (Al), copper (Cu), or is formed by mixing two or more materials. A liquid crystal display device. The liquid crystal display device according to claim 1, wherein the conductive material has a content of 40 to 80%. The liquid crystal of claim 1, wherein the glass frit comprises lead oxide (PbO), zinc oxide (ZnO), silicon oxide (SiO ₂ ), barium oxide (BaO) powder, and a filler. Display. The liquid crystal display device according to claim 1, wherein the glass frit has a content of 20 to 40%. Mixing a conductive material, an organic binder, a solvent, and a glass frit to form a metal paste; Adsorbing the metal paste on both outer sides of the long-axis direction of the sealed glass tube in which a fluorescent material is formed on the inner wall and the mixed gas is contained; Heat-treating the metal paste adsorbed on both outer surfaces of the sealed glass tube; And Disposing a sealed glass tube formed by heat treating the metal paste under the liquid crystal panel. The method of claim 6, wherein the conductive material is formed of any one of platinum (Pt), silver (Ag), lead (Pb), aluminum (Al), copper (Cu), or is formed by mixing two or more materials A method of manufacturing a liquid crystal display device. The method of claim 6, wherein the conductive material has a content of 40 to 80%. The method of claim 6, wherein the organic binder is one of cellulose, acryl, epoxy, and urethane. The method of claim 6, wherein the organic binder has a content of 0.2 to 15%. The method of claim 6, wherein the solvent is any one of isopropyl alcohol (IPA), EA, methyl ethyl ketone (MEK), and acetone having a content of 10 to 50%. The liquid crystal of claim 6, wherein the glass frit comprises lead oxide (PbO), zinc oxide (ZnO), silicon oxide (SiO ₂ ), barium oxide (BaO) powder, and a filler. Method for manufacturing a display device. The method of claim 6, wherein the glass frit has a content of 20 to 40%. The method of claim 6, wherein the metal paste may further include a plasticizer and a surfactant. 15. The method of claim 14, wherein the surfactant has a content of 0.1 to 1%. The method of claim 14, wherein the plasticizer has a content of 0.1 to 3%. The method of claim 6, wherein the heat treatment is performed in a range of 250 ° C. to 400 ° C. 8.

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