KR20060040094A - Lamp and liquid crystal display device having the same - Google Patents

Abstract

Disclosed are a lamp having improved driving characteristics and a liquid crystal display having the same. The lamp includes a body into which discharge gas is injected, a fluorescent film formed on an inner wall of the body, an internal electrode disposed inside the body, and a dielectric film formed on a surface of the internal electrode. As a dielectric film is formed on the surface of the internal electrode, capacitance is formed in the lamp itself. Therefore, the liquid crystal display device can drive a plurality of lamps in parallel with one inverter, thereby reducing the manufacturing cost.

Description

Lamp and liquid crystal display having the same {LAMP AND LIQUID CRYSTAL DISPLAY DEVICE HAVING THE SAME}

1 is a perspective view showing a lamp according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the length direction of the lamp illustrated in FIG. 1.

3 is a perspective view showing a lamp according to another embodiment of the present invention.

4 is a cross-sectional view taken along a length direction of the lamp illustrated in FIG. 3.

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

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

100: lamp 115: discharge gas

130: internal electrode 135: dielectric film

200: inverter 300: liquid crystal display panel

400: drive circuit 500: storage container

600: optical member 700: top chassis

900 liquid crystal display device

The present invention relates to a lamp and a liquid crystal display having the same, and more particularly, to a lamp for generating light and a liquid crystal display for displaying an image using the same.

In general, a liquid crystal display (LCD) is a flat panel display that displays an image by using the electrical and optical characteristics of a liquid crystal having an intermediate characteristic between a liquid and a solid. It is thin and light, has a low driving voltage and low power consumption, and thus is widely used throughout the industry.

Such a liquid crystal display device requires a backlight assembly for supplying additional light because the liquid crystal display panel for displaying an image is a non-light emitting device that does not emit light by itself.

In the backlight assembly, the light source is mainly used a long cylindrical cold cathode fluorescent lamp (CCFL). The cold cathode fluorescent lamp includes a lamp body made of glass and an internal electrode disposed inside the lamp body to apply a discharge voltage. Recently, as a liquid crystal display device is enlarged, a backlight assembly having high brightness and providing uniform light over a large area is required. In order to meet this demand, the backlight assembly needs a plurality of lamps. However, lamps with internal electrodes individually require inverters for driving. Therefore, as the number of lamps is increased, the number of inverters is also increased, thereby increasing the manufacturing cost.

Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a lamp which can reduce the manufacturing cost by enabling parallel operation.

Another object of the present invention is to provide a liquid crystal display having the lamp as described above.

A lamp for achieving the object of the present invention includes a body, a fluorescent film, an internal electrode and a dielectric film. Discharge gas is injected into the body. The fluorescent film is formed on the inner wall of the body. The internal electrode is disposed inside the body. The dielectric film is formed on the surface of the internal electrode. These internal electrodes are formed at both ends of the body. The lamp further includes a lead formed to be connected to the protective film and the internal electrode formed between the fluorescent film and the inner wall of the body and drawn out of the body.

A liquid crystal display device for achieving another object of the present invention includes a plurality of lamps, an inverter and a liquid crystal display panel. The lamps include a body into which discharge gas is injected, a fluorescent film formed on an inner wall of the body, an internal electrode disposed inside the body, and a dielectric film formed on a surface of the internal electrode. The inverter applies a driving voltage for the light emission of the lamps to the lamps. The liquid crystal display panel displays an image using light emitted from the lamps. At this time, the inverter is connected in parallel with the lamps. The liquid crystal display further includes an accommodating container accommodating lamps, an optical member disposed above the lamps, and a top chassis for fixing the liquid crystal display panel.

According to such a lamp and a liquid crystal display having the same, parallel driving of a plurality of lamps is possible, and manufacturing cost can be reduced by reducing the number of inverters due to parallel driving.

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

1 is a perspective view showing a lamp according to an embodiment of the present invention, Figure 2 is a cross-sectional view taken along the longitudinal direction of the lamp shown in FIG.

1 and 2, the lamp 100 includes a body 110, a fluorescent film 120, an internal electrode 130, and a dielectric film 135.

The body 110 has an inner space and is formed of a material that can transmit light. For example, the body 110 has an elongated cylindrical shape and is made of a glass material. The discharge gas 115 for emitting light of the lamp 100 is injected into the body 110. For example, the discharge gas 115 may include mercury (Hg), neon (Neon, Ne), xenon (Xenon, Xe), krypton (Kr), trace amounts of argon (Argon, Ar), and the like. Both ends of the body 110 are sealed to prevent leakage of the discharge gas 115.

The fluorescent film 120 is made of a fluorescent material and is formed on the inner wall of the body 110. The fluorescent film 120 is excited by ultraviolet rays generated by the discharge gas 115 through plasma discharge to emit visible light.

The internal electrode 130 is formed at both ends of the body 110. A driving voltage for emitting the lamp 100 from the outside is applied to the internal electrode 130. Therefore, an electric field difference is formed between the internal electrodes 130, and a discharge phenomenon occurs inside the body 110. Electrons generated by the discharge move across the body 110 at high speed toward the internal electrode 130 having a positive polarity. In this process, electrons collide with a discharge gas 115 such as mercury (Hg) injected into the body 110. As a result, the discharge gas 115 is dissociated into ions, electrons, neutrons, and the like. As a result, a conductive plasma environment is created inside the body 110. Light having a predetermined wavelength, for example, ultraviolet rays generated in the process of forming the plasma environment, stimulates the fluorescent material of the fluorescent film 120 to induce visible light to be used in the display.

The internal electrode 130 has a cylindrical shape. The internal electrode 130 may be made of various metal materials. For example, the internal electrode 130 is made of metal such as nickel (Ni), molybdenum (Mo), niobium (Nb), or the like. These metals have a low work function value. Therefore, the internal electrode 130 using these metals can be discharged even with a relatively low driving voltage compared to using metals having a high work function.

The dielectric layer 135 is formed on the surface of the internal electrode 130. The dielectric layer 135 may be formed by various dielectric materials. For example, the dielectric layer 135 may be formed of a material having a low dielectric constant such as silicon oxide (SiO 2) or silicon nitride (Si 3 N 4) to tantalum oxide (Ta 2 O 5), aluminum oxide (Al 2 O 3), hafnium oxide (HfO 2), or zirconium oxide ( ZrO2), barium strontium titanium oxide ((Ba, Sr) TiO3, BST) and lead zirconium titanium oxide (Pb (Zr, Ti) O3, PZT) can be formed of any one of a variety of materials, such as . The dielectric layer 135 is formed by coating the surface of the internal electrode 130. For example, a method of coating includes sputtering and a Sol-gel process.

The dielectric layer 135 is disposed between the discharge gas 115 and the internal electrode 130. Here, the discharge gas 115 has electrical conductivity through plasma discharge. The internal electrode 130 is also a conductive conductor. Accordingly, a dielectric film 135 is formed between the discharge gas 115 and the internal electrode 130 having electrical conductivity to form a capacitance. In this case, the dielectric film 135 may be formed on the entire surface of at least the internal electrode 130 protruding into the body. By forming the dielectric film 135 between the internal electrode 130 and the plasma, the same effect as that of connecting a stabilizing capacitor (Ballast Capacitor) in series to the lamp 100 is generated.

Meanwhile, the dielectric layer 135 may be freely adjusted in thickness and area through various process conditions. In this case, capacitance is directly proportional to the area of the dielectric layer 135 and inversely proportional to the thickness of the dielectric layer 135. Therefore, the desired capacitance can be freely set by adjusting the area and thickness of the dielectric layer 135. In particular, unlike an area of the dielectric layer 135 that is limited by the surface area of the internal electrode 130, the thickness of the dielectric layer 135 may be more easily adjusted. As a result, driving conditions for driving the lamp 100 may vary.

As such, by forming the dielectric layer 135 on the surface of the internal electrode 130, the plurality of lamps 100 may be driven in parallel using one external driving voltage. In other words, one inverter (not shown) that outputs a driving voltage for emitting the lamps 100 may drive the plurality of lamps 100 simultaneously.                     

The lamp 100 further includes a passivation layer 140 and a lead part 150. The passivation layer 140 is formed between the fluorescent film 120 and the inner wall of the body 110. The protection layer 140 protects the inner wall of the body 110 from the discharge gas 115 to extend the life of the lamp 100. The lead unit 150 is connected to the internal electrode 130 and drawn out of the body 110, and transfers a driving voltage applied from the outside to the internal electrode 130. In this case, the lead unit 150 is made of a conductive material and is electrically connected to the internal electrode 130.

3 is a perspective view illustrating lamps according to another embodiment of the present invention, and FIG. 4 is a cross-sectional view taken along a length direction of the lamp illustrated in FIG. 3. In the present embodiment, since the remaining components except for the internal electrode have the same configuration as shown in FIGS. 1 and 2, the same reference numerals are used for the same components, and detailed description thereof will be omitted.

3 and 4, the internal electrode 160 is disposed at both ends of the body 110, and its shape is a funnel shape. A recessed groove 162 is formed at one end of the internal electrode 160. As a result, the surface area of the internal electrode 160 increases. If the surface area of the internal electrode 160 is increased, the capacitance is increased to improve the discharge efficiency. On the other hand, when the current supplied is constant, when the surface area of the electrode is wide, the electron density of the electrode is lower than that of the electrode having a relatively small surface area. When the electron density decreases, the electric attraction between the ions and the electrodes in the body 110 is weakened, thereby reducing the phenomenon in which the hydrogen ions (Hg +) and the like collide with the internal electrodes 160 in the plasma state. Therefore, damage to the internal electrode 160 due to the collision is prevented to increase the life of the internal electrode 160. Unlike the present embodiment, the internal electrode 160 may be formed in various shapes to increase the surface area.

The dielectric layer 135 is formed on the surface of the internal electrode 160. The dielectric layer 135 may be formed on the entire surface of the internal electrode 160 protruding at least inside the body regardless of the shape of the internal electrode 160. Capacities are formed by forming internal electrodes 160 having dielectric layers 135 formed on surfaces thereof at both ends of the lamp 100, and thus, the plurality of lamps 100 may be driven in parallel using one external driving voltage.

5 is an exploded perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention. Referring to FIG. 5, the liquid crystal display device 900 includes a plurality of lamps 100, an inverter 200, and a liquid crystal display panel 300.

Since the lamp 100 is the same as described with reference to FIGS. 1 and 2 or 3 and 4, a detailed description thereof will be omitted.

The inverter 200 is disposed outside the storage container 500 and outputs a driving voltage for emitting light of the lamps 100. The inverter 200 boosts and outputs an AC voltage having a low voltage applied from the outside to an AC voltage having a high voltage for driving the lamps 100. The driving voltage generated from the inverter 200 is applied in parallel to the plurality of lamps 100 through the power supply line 210.

For example, the inverter 200 corresponds to both ends of the lamp 100 through the flexible circuit board 220 (FCB) disposed on the side 520 of the storage container 500, the plurality of lamps 100 Are connected in parallel. The flexible circuit board 220 is electrically connected to a power supply line 210 connected to the inverter 200 and a lead part (not shown) protruding from both ends of the lamp 100. Accordingly, the driving voltage output through the inverter 200 is applied to the respective lamps 100 through the flexible circuit board 220. In this case, a predetermined voltage and a current are supplied to each of the lamps 100 by the capacitance of the internal electrodes disposed on both ends of the lamp 100 and having a dielectric film formed on a surface thereof.

The liquid crystal display panel 300 displays an image using light emitted from the lamps 100. The liquid crystal display panel 300 includes a thin film transistor (hereinafter, referred to as TFT) substrate 310, a color filter substrate 320 coupled to the TFT substrate 310, and between the two substrates 310 and 320. The liquid crystal 330 is interposed therebetween.

The TFT substrate 310 is a transparent glass substrate on which a switching element TFT (not shown) is formed in a matrix form. Data and gate lines are respectively connected to the source and gate terminals of the TFTs, and a pixel electrode (not shown) made of a transparent conductive material is connected to the drain terminal.

The color filter substrate 320 is a substrate in which RGB pixels (not shown) which are color pixels are formed by a thin film process. A common electrode (not shown) made of a transparent conductive material is formed on the color filter substrate 320.

The liquid crystal 330 is a material having an intermediate state between a crystal and a liquid. The liquid crystal 330 is made of a material having a state in which the center of gravity of a unit molecule is irregular but regularity in a direction is maintained to some extent. The liquid crystal 330 is interposed between the TFT substrate 310 and the color filter substrate 320. In this case, an electric field is formed between the pixel electrode and the common electrode by a driving signal transmitted from the outside. The directivity of the liquid crystal 330 is changed by this electric field to change the transmittance of light emitted through the liquid crystal 330. Accordingly, the liquid crystal display panel 300 may display images having various colors by adjusting the light transmittance as desired.

The liquid crystal display device 900 further includes a driving circuit unit 400 for driving the liquid crystal display panel 300. The driving circuit unit 400 provides data for providing driving signals and data for applying driving signals provided from the gate printed circuit boards 410 and 420 and the data and gate printed circuit boards 410 and 420 to the liquid crystal display panel 300. The flexible circuit film 430 and the gate flexible circuit film 440 are formed. In this case, each of the data and gate flexible circuit films 430 and 440 controls the driving signals to apply the driving signals provided from the data and gate printed circuit boards 410 and 420 to the liquid crystal display panel 300 at an appropriate timing. Data and gate driving chips 432 and 442 are further included. Accordingly, the liquid crystal display panel 300 may adjust the direction of the liquid crystal 330 in response to the driving signal output from the driving circuit unit 400 to implement an image having a desired gray scale.

The liquid crystal display device 900 includes a storage container 500 for accommodating the lamps 100, an optical member 600 disposed on the lamps 100, and a top chassis 700 for fixing the liquid crystal display panel 300. More).

The storage container 500 includes a bottom portion 510 and a side portion 520 extending from an edge of the bottom portion 510 to provide a storage space. The storage container 500 may be formed of various materials. For example, the storage container 500 is made of a metal having excellent strength and little deformation.

The optical member 600 is disposed above the lamps 100. The optical member 600 improves the brightness characteristic of the light emitted from the lamps 100. The optical member 600 includes a diffusion plate 610 and an optical sheet 620 disposed on the diffusion plate 610. The diffusion plate 610 is disposed above the lamps 100 to diffuse light incident from the lamps 100 to improve luminance uniformity of the emitted light. For example, the diffusion plate 610 is formed of a poly methyl methacrylate (PMMA) material. The optical sheet 620 is disposed on the diffuser plate 610. The optical sheet 620 serves to improve luminance uniformity or to improve front luminance by changing a path of light emitted through the diffusion plate 610. For example, the optical sheet 620 is made of a light collecting sheet for condensing the light diffused through the diffuser plate 610 to improve the front brightness, or diffuse the light diffused through the diffuser plate 610 once again. It is made of a diffusion sheet to make. The liquid crystal display device 900 may add or remove a separate optical sheet having various functions according to required luminance characteristics.

The top chassis 700 is coupled to the storage container 500 while surrounding the edge of the liquid crystal display panel 300 to fix the liquid crystal display panel 300. The top chassis 700 prevents the liquid crystal display panel 300 from being damaged by an external impact and prevents the liquid crystal display panel 300 from being separated.

The liquid crystal display 900 includes a reflector (not shown) for reflecting light generated from the lamp 100 in the direction of the optical member 600, a lamp holder 170 for fixing the lamp 100, and a side mold 810. And a middle mold 820.

 For example, the reflective plate is attached to the bottom 510 of the storage container 500. The reflecting plate reflects the light toward the bottom 510 of the light generated from the lamps 100 toward the optical member 600 to improve light utilization efficiency.

The lamp holder 170 is disposed at both ends of the lamps 100 and fixes the lamps 100 to the storage container 500. For example, one lamp holder 170 fixes two lamps 100 adjacent to each other.

The side mold 810 covers both ends of the lamps 100 in which light is not actually generated and supports the optical member 600.

The middle mold 820 is coupled to the side portion 520 of the storage container 500 while pressing the edge of the upper surface of the optical member 600. The middle mold 820 guides the storage position of the liquid crystal display panel 300 and supports the liquid crystal display panel 300.

According to such a lamp and a liquid crystal display having the same, a dielectric film is formed on a surface of an internal electrode disposed inside the lamp to serve as a stabilizing capacitor, thereby driving a plurality of lamps in parallel with one inverter. Thus, the number of inverters and other related components can be reduced to reduce manufacturing costs. In addition, since the desired capacitance may be set by adjusting the thickness and area of the dielectric layer, various driving conditions of the lamp may be set. Moreover, since the lamps emit light having a constant brightness through parallel driving, the brightness uniformity can be improved.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will be variously modified and changed within the scope of the present invention without departing from the spirit and scope of the present invention described in the claims below. I can understand that you can.

Claims (7)

A body in which discharge gas is injected; A fluorescent film formed on an inner wall of the body; Internal electrodes disposed in the body; And Lamp comprising a dielectric film formed on the surface of the internal electrode. The lamp of claim 1, wherein the internal electrodes are formed at both ends of the body. The lamp of claim 1, further comprising a protective film formed between the fluorescent film and an inner wall of the body. The lamp of claim 1, further comprising a lead connected to the internal electrode and drawn out of the body. A plurality of lamps including a body into which discharge gas is injected, a fluorescent film formed on an inner wall of the body, an inner electrode disposed inside the body, and a dielectric film formed on a surface of the inner electrode; An inverter applying a driving voltage for emitting the lamps to the lamps; And And a liquid crystal display panel configured to display an image by using the light emitted from the lamps. The liquid crystal display of claim 5, wherein the inverter is connected in parallel with the lamps. The method of claim 5, A storage container accommodating the lamps; An optical member disposed above the lamps; And And a top chassis for fixing the liquid crystal display panel.

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