Flat-type fluorescent lamp and liquid crystal display device having the same

A flat-type fluorescent lamp includes a lamp body and a first external electrode. The first external electrode is positioned on an end portion of the lamp body. The first external electrode includes a main electrode portion and a first auxiliary electrode portion. The main electrode portion crosses end portions of the discharge spaces. The first auxiliary electrode portion protrudes from the main electrode portion. The first auxiliary electrode portion corresponds to an outer discharge space adjacent to a side of the lamp body. Therefore, a luminance of the flat-type fluorescent lamp may be made more uniform, thereby improving an image display quality. In addition, operation of the flat-type fluorescent lamp at a low temperature may be improved.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority from Korean Patent Application No. 2005-00534, filed on Jan. 4, 2005, the disclosure of which is hereby incorporated herein by reference in its entirety.

BACKGROUND

1. Field of the Invention

The present invention relates to a flat-type fluorescent lamp and a liquid crystal display (LCD) device having the flat-type fluorescent lamp. More particularly, the present invention relates to a flat-type fluorescent lamp capable of providing uniform luminance and an LCD device including the flat-type fluorescent lamp.

2. Description of the Related Art

An LCD device displays an image using a liquid crystal layer having optical characteristics such as anisotropy of refractivity and electrical characteristics such as anisotropy of dielectric constant. LCD devices can provide various desirable characteristics over cathode ray tube (CRT) or plasma display panel (PDP) devices, such as a thin profile, lower driving voltage, and lower power consumption.

An LCD panel is non-emissive type display device which requires a light source to supply the LCD panel of the LCD device with light for producing visible images.

The typical LCD device includes a cold cathode fluorescent lamp CCFL having a thin cylindrical shape that is extended in a predetermined direction. An LCD device having a large viewing area typically includes a plurality of CCFLs. As the number of CCFLs in the LCD device is increased, the manufacturing cost of the LCD device also increases, and optical characteristics such as luminance uniformity may be adversely affected.

Accordingly, a flat-type fluorescent lamp has been developed. The flat-type fluorescent lamp includes a lamp body having a plurality of discharge spaces and an external electrode through which a discharge voltage is applied to the lamp body. An inverter applies the discharge voltage to the external electrode to form a plasma discharge in the discharge spaces. An ultraviolet light generated in the discharge spaces is converted into a visible light by a fluorescent layer formed on an inner surface of the lamp body.

During operation of the flat-type fluorescent lamp, the luminance of the outer discharge spaces is lower than that of the central discharge spaces. The luminance difference is created by a parasitic capacitance between the flat-type fluorescent lamp and a metal receiving container. In addition the plasma discharge is not generated in the outer discharge spaces at low temperatures. As a result, the luminance uniformity and image display quality may be adversely affected.

SUMMARY

In accordance with the present invention, a flat-type fluorescent lamp capable of providing uniform light luminance is provided.

In accordance with the present invention, a liquid crystal display (LCD) device having the above-mentioned flat-type fluorescent lamp is also provided.

A flat-type fluorescent lamp in accordance with an aspect of the present invention includes a lamp body and a first external electrode. The lamp body includes a plurality of discharge spaces for generating light. The first external electrode is positioned on an end portion of the lamp body through which a discharge voltage is applied. The first external electrode includes a main electrode portion and a first auxiliary electrode portion. The main electrode portion crosses end portions of the discharge spaces. The first auxiliary electrode portion protrudes from the main electrode portion. The first auxiliary electrode portion corresponds to an outer discharge space adjacent to a side of the lamp body.

A flat-type fluorescent lamp in accordance with another aspect of the present invention includes a lamp body, a first external electrode, and a floating electrode. The lamp body includes a plurality of discharge spaces for generating light. The first external electrode is positioned on an end portion of the lamp body through which a discharge voltage is applied. The first external electrode includes a main electrode portion and an auxiliary electrode portion. The main electrode portion crosses end portions of the discharge spaces. The auxiliary electrode portion protrudes from the main electrode portion. The auxiliary electrode portion corresponds to an outer discharge space adjacent to a side of the lamp body. The floating electrode member is spaced apart from the auxiliary electrode portion. The floating electrode member has a shorter width than the auxiliary electrode portion.

An LCD device in accordance with an exemplary embodiment of the present invention includes a flat-type fluorescent lamp, a receiving container, an inverter, and an LCD panel. The flat-type fluorescent lamp includes a lamp body and a first external electrode. The lamp body includes a plurality of discharge spaces for generating light. The first external electrode is positioned on an end portion of the lamp body through which a discharge voltage is applied. The first external electrode includes a main electrode portion and a first auxiliary electrode portion. The main electrode portion crosses end portions of the discharge spaces. The first auxiliary electrode portion protrudes from the main electrode portion. The first auxiliary electrode portion corresponds to an outer discharge space adjacent to a side of the lamp body. The receiving container receives the flat-type fluorescent lamp. The inverter applies the discharge voltage to the flat-type fluorescent lamp. The LCD panel displays an image using the light generated from the flat-type fluorescent lamp.

As a result, the luminance of the outer discharge spaces may be increased so that the luminance of the flat-type fluorescent lamp is made more uniform, thereby improving the image display quality. In addition, operation of the flat-type fluorescent lamp at a low temperature may be improved.

DESCRIPTION OF THE EMBODIMENTS

It should be understood that the exemplary embodiments of the present invention described herein may be varied and modified in many different ways without departing from the inventive principles disclosed herein, and the scope of the present invention is therefore not limited to these particular embodiments. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the invention to those skilled in the art by way of example and not of limitation.

FIG. 1is a perspective view showing a flat-type fluorescent lamp in accordance with an exemplary embodiment of the present invention.FIG. 2is a plan view showing the flat-type fluorescent lamp shown inFIG. 1.

Referring toFIGS. 1 and 2, the flat-type fluorescent lamp100includes a lamp body200and a first external electrode310. In this exemplary embodiment, the flat-type fluorescent lamp100includes two first external electrodes310. The lamp body200is divided into a plurality of discharge spaces. Light is generated in the discharge spaces. A discharge voltage is applied from an inverter (not shown) to the lamp body200through the first external electrodes310.

The lamp body200has a substantially rectangular shape when viewed from a plan view of the flat-type fluorescent lamp100. When the discharge voltage is applied to the lamp body200through the first external electrodes310, a plasma discharge is formed. Ultraviolet light generated by the plasma discharge is converted into light in the visible spectrum so that the flat-type fluorescent lamp100emits visible light. The lamp body200includes a light emitting area LA and one or more peripheral areas PA adjacent the ends of light emitting area LA. Light is generated in the light emitting area LA. The peripheral areas are defined by the portions of the second substrate220which are covered by the second external electrodes320. The lamp body200has a wide light emitting area LA, and the lamp body200includes discharge spaces so that a uniform luminance of visible light may be produced, and a light emitting efficiency of the flat-type fluorescent lamp100is increased with respect to a conventional cold cathode fluorescent lamp (CCFL). The lamp body200includes a first substrate210and a second substrate220.

The first external electrodes310are provided on a lower surface of the first substrate210. Thus, the first external electrodes310are on an external surface of the lamp body200. Each of the first external electrodes310is positioned on end portions of the discharge spaces, and crosses laterally across the end portions of the discharge spaces.

Each of the first external electrodes310comprises a main electrode portion312in the peripheral area PA, a first auxiliary electrode portion314in the light emitting area LA, and a second auxiliary electrode portion316in the light emitting area LA. The main electrode portion312has uniform a width, and crosses the end portions of all of the discharge spaces. The first auxiliary electrode portion314corresponds to an end portion of an outer discharge space, and protrudes from the main electrode portion312toward a center of the outer discharge space. The second auxiliary electrode portion316protrudes from the first auxiliary electrode portion314toward the center of the outer discharge space. The second auxiliary electrode portion316is adjacent an edge of the lamp body200and extends along a lower edge of the first substrate210.

Each of the first external electrodes310comprises a conductive material so that the discharge voltage is applied from the inverter to the lamp body200through the first external electrode310. In this exemplary embodiment, a silver paste comprising a mixture of silver (Ag) and silicon oxide (SiO2) is coated on the lamp body200to form the first external electrodes310. Alternatively, metal powder may be coated on the lamp body200to form the first external electrodes310.

The flat-type fluorescent lamp100may further include second external electrodes320. The second external electrodes320are provided on an upper surface of the second substrate220. Thus, the second external electrodes320are on an upper external surface of the lamp body200. Each of the second external electrodes320is provided on the end portions of the discharge spaces opposite the first external electrodes310. In this exemplary embodiment, the second external electrodes320do not include extensions corresponding to the second auxiliary electrode316of the first external electrodes310. That is, each of the second external electrodes320has a shape which only corresponds to the main electrode portion312and the first auxiliary electrode portion314of the first external electrodes310. The second external electrodes320may comprise the same material and may be formed using the same method as the first external electrodes310.

FIG. 3is a cross-sectional view taken along a line I-I′ shown inFIG. 1.

Referring toFIGS. 1 and 3, the flat-type fluorescent lamp100includes the lamp body200, the first external electrodes310that are positioned on the bottom of the lamp body200, and the second external electrodes320that are positioned on the top of the lamp body200.

The lamp body200includes the first substrate210on which the first external electrode310is formed and the second substrate220that is combined with the first substrate210to form the discharge spaces230.

The first substrate210has a substantially rectangular plate shape. In this exemplary embodiment, the first substrate210comprises a glass including a material that blocks UV light.

The second substrate220comprises a material transparent to light in the visible spectrum so that visible light may pass through the second substrate220. For example, the second substrate220may also comprise a glass including a material that blocks UV light.

The second substrate220includes a plurality of discharge space portions222, a plurality of space dividing portions224, and a sealing portion226. The discharge space portions222are spaced apart from the first substrate210to form the discharge spaces230between the first substrate210and the second substrate220. The space dividing portions224are located between the discharge space portions222, and make contact with the first substrate210to define sides of the discharge spaces230. The sealing portion226is adjacent to the edges of the second substrate220to form a seal with the first substrate210along the sides of the second substrate220. The sealing portion226surrounds the discharge space portions222and the space dividing portions224.

The second substrate220may be formed through a molding process. That is, a glass plate is heated and pressed to form the second substrate220having the discharge space portions222, the space dividing portions224, and the sealing portion226. Alternatively, the second substrate220may be formed through a blow molding process. In the blow molding process, a glass plate is heated and molded using compressed air to form the second substrate220.

As shown inFIG. 3, the cross-sectional view of the lamp body200shows that the second substrate220forms a plurality of connected trapezoidal shapes. Each of these trapezoidal shapes form the walls of the discharge space portions222. The trapezoidal shapes have rounded corners, and are arranged substantially parallel to each other. Alternatively, the cross-section of the discharge space portions222may have a semicircular shape, a rectangular shape, a polygonal shape, etc.

A connecting passage228is formed on the second substrate220to connect adjacent discharge spaces230. In this exemplary embodiment, at least one connecting passage228is formed on each of the space dividing portions224. Each of the connecting passages228is spaced apart from the first substrate210by a predetermined distance. The connecting passages228may be formed through the molding process for forming the second substrate220. The discharge gas that is injected into one of the discharge spaces230may pass through each of the connecting passages228so that pressure in the discharge spaces230is substantially equal to one another. Each of the connecting passages228may be formed in a variety of shapes, such as a curved ‘S’ shape. When each of the connecting passages228has the ‘S’ shape, a path length between the adjacent discharge spaces230is increased so that a current formed by the discharge voltage flows more uniformly through the discharge spaces230.

An adhesive240such as frit is interposed between the first and second substrates210and220to bond the first substrate210with the second substrate220. The frit may comprise a mixture of glass and metal having a melting point lower than pure glass. Thus, the adhesive240is prepared on the sealing portion226of the first and second substrates210and220, and the adhesive240is fired and solidified. The adhesive240is fired at a temperature of about 400° C. to about 600° C., which causes the frit adhesive240to melt, but not melt the glass forming the first and second substrates210and220. When the adhesive240is allowed to solidify, the frit will solidly bond the first and second substrates210and220.

The space dividing portions224of the second substrate220are sealed with the first substrate210by a pressure difference between the discharge spaces230and outside of the flat-type fluorescent lamp100. In particular, the first substrate210is combined with the second substrate220, and the air between the first and second substrates210and220is discharged causing the discharge spaces230to be evacuated. A discharge gas is injected into the evacuated discharge spaces230. In this exemplary embodiment, a pressure of the discharge gas in the discharge spaces230is about 50 Torr to 70 Torr, and an atmospheric pressure outside of the flat-type fluorescent lamp100is about 760 Torr, thereby forming the pressure difference. Therefore, the space dividing portions224are sealed with the first substrate210.

The lamp body200further includes a first fluorescent layer250and a second fluorescent layer260. The first fluorescent layer250is provided on an upper surface of the first substrate210, such that the first fluorescent layer250covers the lower walls of the discharge spaces230. The second fluorescent layer260is provided on a lower surface of the second substrate220, such that the second fluorescent layer260covers the upper and side walls of the discharge spaces230. When the ultraviolet light generated by the plasma discharge is irradiated onto the first and second fluorescent layers250and260, excitons are generated in the first and second fluorescent layers250and260. When an energy level of the excitons decreases, the first and second fluorescent layers250and260emit light in the visible spectrum.

The lamp body200further includes a reflecting layer270interposed between the first substrate210and the first fluorescent layer250. A portion of the visible light is reflected from the reflecting layer270toward the second substrate220to prevent the visible light generated by the first and second fluorescent layers250and260from leaking through the first substrate210. In this exemplary embodiment, the reflecting layer270comprises a metal oxide such as aluminum oxide (Al2O3) or barium sulfate (BaSO4) to increase a light reflectivity of the reflecting layer270and a color reproducibility of a display device incorporating the flat-type fluorescent lamp100.

The first fluorescent layer250and the reflecting layer270may be formed on the first substrate210, and the second fluorescent layer260may be formed on the second substrate220through a spray coating method. In this exemplary embodiment, the first fluorescent layer250and the reflecting layer270are formed on the upper surface of the first substrate210surrounded by the sealing portion226, and the second fluorescent layer260is formed on the lower surface of the second substrate220surrounded by the sealing portion226. Alternatively, the first and second fluorescent layers250and260and the reflecting layer270may not be formed between the space dividing portions224and the first substrate210.

The lamp body200may further include a protecting layer (not shown) between the first substrate210and the reflecting layer270and/or between the second substrate220and the second fluorescent layer260. The protecting layer (not shown) prevents a chemical reaction between mercury (Hg) in the discharge gas and the first or second substrate210or220to prevent a loss of the mercury and to reduce black spots from forming on the inner surface of the lamp body200.

FIG. 4is an enlarged plan view showing a portion of the first external electrode shown inFIG. 2.

Referring toFIG. 4, each of the first external electrodes310includes the main electrode portion312that crosses the end portions of the discharge spaces, the first auxiliary electrode portion314protruding from the main electrode portion312, and the second auxiliary electrode portion316protruding from the first auxiliary electrode portion314.

The main electrode portion312extends in a direction substantially perpendicular to a longitudinal direction of each of the discharge spaces. The main electrode portion312has a substantially uniform width LW. In this exemplary embodiment, the main electrode portion312has a width LW of about 10 mm.

The first auxiliary electrode portion314corresponds to each of the end portions of the outer discharge spaces. When the flat-type fluorescent lamp100is received in a metallic receiving container, the outer discharge spaces make contact with bottom plate and sidewalls of the receiving container. As a result, the parasitic capacitance of the outer discharge spaces is greater than a parasitic capacitance of the remaining inner discharge spaces that only make contact with the bottom plate of the receiving container. When the parasitic capacitance is increased, the amount of current from the discharge voltage which flows toward the receiving container is also increased, thereby decreasing the luminance of the light generated in the outer discharge spaces.

The end portions of each of the first external electrodes310includes a first auxiliary electrode portion314to increase the overlapping area between the first external electrode310and the outer discharge spaces. InFIGS. 1 to 4, the first auxiliary electrode portion314overlaps with a portion of the light emitting area LA of the flat-type fluorescent lamp100. Alternatively, the first auxiliary electrode portion314may be partially overlapped with the light emitting area LA, or the first auxiliary electrode portion314may be in the peripheral area PA. The first auxiliary electrode portion314protrudes from the main electrode portion312toward the center of each of the outer discharge spaces by a first length L1. When the first length L1is increased, the luminance of the light generated in the outer discharge spaces is also increased. However, when the first length L1is too long, the light generated in the outer discharge spaces is blocked by the first auxiliary electrode portion314, thereby decreasing the luminance of the light generated from the outer discharge spaces. In this exemplary embodiment, the first length L1is about 2 mm to about 3 mm. The first auxiliary electrode portion314has a width W1. In this exemplary embodiment, the width W1of the first auxiliary electrode portion314is about 10 mm.

The end portions of each of the first external electrodes310includes a second auxiliary electrode portion316to further increase the overlapping area between the first external electrode310and the outer discharge spaces. InFIGS. 1 to 4, the second auxiliary electrode portion316overlaps with the light emitting area LA of the flat-type fluorescent lamp100. The second auxiliary electrode portion316protrudes from the first auxiliary electrode portion314toward the center of the outer discharge spaces by a second length L2. The second auxiliary electrode portion316increases luminance uniformity of the flat-type fluorescent lamp100.

As the second length L2is increased, the luminance of the light generated in the outer discharge spaces also increases. As a result, the luminance of the light generated in each of the outer discharge spaces can be made to be substantially equal to that of the light generated in each of the remaining discharge spaces. In this exemplary embodiment, the second length L2is more than about 10 mm. The second auxiliary electrode portion316has a second width S2that is shorter than the first width W1. In addition, the second auxiliary electrode portion316is positioned along an edge of the first substrate210so that the amount of light generated in the outer discharge spaces which is blocked by the second auxiliary electrode portion316is minimized. Furthermore, the second auxiliary electrode portion316decreases a distance between the first external electrodes310on either end of the outer discharge space. As a result, the plasma discharge can be more easily formed in the outer discharge spaces during an initial stage of the operation of the flat-type fluorescent lamp100. The second auxiliary electrode portion316has a smaller width than that of the first auxiliary electrode portion314, thereby reducing dark spots from forming in the display image.

In this exemplary embodiment, the main electrode portion312, the first auxiliary electrode portion314, and the second auxiliary electrode portion316comprise substantially the same material. Alternatively, the main electrode portion312, the first auxiliary electrode portion314, and the second auxiliary electrode portion316may comprise different materials. For example, the first auxiliary electrode portion314and/or the second auxiliary electrode portion316may comprise a transparent conductive material.

FIG. 5is a plan view showing a flat-type fluorescent lamp in accordance with another exemplary embodiment of the present invention.FIG. 6is an enlarged plan view showing a first external electrode shown inFIG. 5. The flat-type fluorescent lamp ofFIGS. 5 and 6is substantially the same as inFIGS. 1 to 4except with respect to the first external electrodes. Thus, the same reference numerals will be used to refer to the same or like parts as those described inFIGS. 1 to 4and any further explanation concerning the above elements will be omitted.

Referring toFIGS. 5 and 6, the flat-type fluorescent lamp400includes first external electrodes410that are formed on a lower surface of the first substrate210and a floating electrode member420.

Each of the first external electrodes410includes a main electrode portion412that crosses end portions of the discharge spaces, a first auxiliary electrode portion414which protrudes from the main electrode portion412, and a second auxiliary electrode portion416which protrudes from the first auxiliary electrode portion414. The main electrode portion412, the first auxiliary electrode portion414, and the second auxiliary electrode portion416have substantially the same structure as shown inFIG. 4. Thus, any further explanation concerning the above elements will be omitted.

The floating electrode member420is spaced apart from the second auxiliary electrode portion416, and is substantially aligned with the second auxiliary electrode portion416. The floating electrode member420comprises a plurality of floating electrodes422. The floating electrode member420is arranged in a direction parallel to the longitudinal direction of the discharge spaces, and has a third length L3. The third length L3is long enough to decrease a light initiating temperature of the flat-type fluorescent lamp400.

In detail, when a discharge voltage is applied to the first external electrodes410, electric fields are generated between the first external electrodes410. When the floating electrode member420is disposed between the first external electrodes410, the electric fields becomes stronger because of electrostatic induction of the first external electrodes410. Therefore, the floating electrode member420lowers the light initiating temperature that is lowered when the electric fields between the first external electrodes410are strengthened.

In this exemplary embodiment, the third length is no less than about 100 mm. The floating electrode member420has a width substantially equal to the width of the second auxiliary electrode portion416. The floating electrode member420is adjacent to the edges of the flat-type fluorescent lamp400.

The floating electrode member420may comprise substantially the same material as the first external electrodes410. Alternatively, the floating electrode member420and the first external electrodes410may comprise different materials. For example, the floating electrode member420may comprise a transparent conductive material so that the floating electrode member420will not block the light generated in the discharge spaces.

According to this exemplary embodiment, an electric field formed in the outer discharge spaces by the floating electrode member420is adjacent to a central portion of the outer discharge spaces. As a result, the plasma discharge may be formed at the low temperature. Alternatively, the floating electrode member420may be formed in the lamp body200.

FIG. 7is a plan view showing a flat-type fluorescent lamp in accordance with another exemplary embodiment of the present invention.FIG. 8is an enlarged plan view showing a first external electrode shown inFIG. 7. The flat-type fluorescent lamp ofFIGS. 7 and 8is substantially the same as inFIGS. 1 to 4except with respect to the first external electrodes. Thus, the same reference numerals will be used to refer to the same or like parts as those described inFIGS. 1 to 4and any further explanation concerning the above elements will be omitted.

Referring toFIGS. 7 and 8, the flat-type fluorescent lamp500includes first external electrodes510that are formed on a lower surface of the first substrate210and a floating electrode member520.

Each of the first external electrodes510includes a main electrode portion512that crosses end portions of the discharge spaces, and a first auxiliary electrode portion514which protrudes from the main electrode portion512.

The main electrode portion512crosses the end portions of the discharge spaces and extends in a direction substantially perpendicular to a longitudinal direction of each of the discharge spaces. The main electrode portion512has a uniform width LW. For example, the width LW of the main electrode portion512is about 10 mm.

The auxiliary electrode portion514corresponds to outer discharge spaces. The auxiliary electrode portion514protrudes from the main electrode portion512toward a center of each of the outer discharge spaces by a first length L1. As the first length L1is increased, the luminance of light generated in the outer discharge spaces is also increased. However, when the first length L1is too long, the light generated in the outer discharge spaces is blocked by the auxiliary electrode portion514, thereby decreasing the luminance of the light generated from the outer discharge spaces. In this exemplary embodiment, the first length L1is about 2 mm to about 3 mm. The first auxiliary electrode portion514has a width W1. In this exemplary embodiment, the width W1of the auxiliary electrode portion514is about 10 mm.

The floating electrode member520is spaced apart from the auxiliary electrode portion514, and extends in a direction substantially parallel to a longitudinal direction of each of the discharge spaces. The floating electrode member520includes a plurality of floating electrodes522. The floating electrode member520has a fourth length L4. The fourth length L4is long enough to decrease a lighting temperature of the flat-type fluorescent lamp500. In this exemplary embodiment, the fourth length L4is no less than about 20 mm. The floating electrode member520has a second width W2that is shorter than the first width W1of the auxiliary electrode portion514. The floating electrode member520is adjacent to the sides of the flat-type fluorescent lamp500. That is, the floating electrode member520is adjacent to a sealing portion222.

The floating electrode member520comprises substantially the same material as the first external electrodes510. Alternatively, the floating electrode member520and the first external electrodes510may comprise different materials. For example, the floating electrode member520may comprise a transparent conductive material so that the floating electrode member520will not block the light generated in the discharge spaces.

In this exemplary embodiment, the auxiliary electrode portion514is formed on the outermost discharge spaces. Alternatively, the auxiliary electrode portion514may be formed on two or three discharge spaces that are adjacent to the sides of the flat-type fluorescent lamp500. In addition, the auxiliary electrode portion514may be formed on various other discharge spaces.

FIG. 9is an exploded perspective view showing an LCD device in accordance with an exemplary embodiment. A flat-type fluorescent lamp ofFIG. 9may be substantially the same as the lamps described above with respect toFIGS. 1 to 8. Thus, the same reference numerals will be used to refer to the same or like parts as those described inFIGS. 1 to 8and any further explanation will be omitted.

Referring toFIG. 9, the LCD device600includes a flat-type fluorescent lamp100that generates light, a receiving container830that receives the flat-type fluorescent lamp100, an inverter610that applies a discharge voltage to the flat-type fluorescent lamp100, and a display unit700that displays an image.

The receiving container830comprises a strong metal to securely receive the flat-type fluorescent lamp100. The receiving container830includes a bottom plate832and a plurality of sidewalls834. The bottom plate832of the receiving container830corresponds to the lower surface of the flat-type fluorescent lamp100. The sidewalls834of the receiving container830correspond to side surfaces of the flat-type fluorescent lamp100. In this exemplary embodiment, each of the sidewalls834is bent twice to form a combining space for combining the sidewalls834with other elements such as a top chassis, a molded frame, etc. The outer discharge spaces of the flat-type fluorescent lamp100are positioned adjacent to the bottom plate832and the sidewalls834of the receiving container830. The remaining inner discharge spaces of the flat-type fluorescent lamp100are only adjacent to the bottom plate832of the receiving container830. Therefore, a parasitic capacitance formed on each of the outer discharge spaces is larger than that of the inner discharge spaces.

The inverter610generates a discharge voltage to drive the flat-type fluorescent lamp100. The inverter610elevates a level of a voltage that is provided by an external source to drive the flat-type fluorescent lamp100. The discharge voltage is applied to the first and second external electrodes310and320through a first power supply line612and a second power supply line614, respectively. In this exemplary embodiment, the first and second external electrodes310and320are provided on the first and second substrates210and220, respectively, and a first conductive clip (not shown) and a second conductive clip (not shown) are electrically connected to the first and second power supply lines612and614, respectively. Each of the first and second conductive clips (not shown) electrically connects the first and second external electrodes310and320with each other.

The display unit700includes an LCD panel710and a driving circuit member720. The LCD panel710displays an image using the light generated from the flat-type fluorescent lamp100. The driving circuit member720applies driving signals to the LCD panel710.

The LCD panel710includes a first substrate712, a second substrate714and a liquid crystal layer716. The second substrate714is aligned with the first substrate712. The liquid crystal layer716is interposed between the first and second substrates712and714.

The first substrate712is a thin film transistor (TFT) substrate having a plurality of TFTs that are arranged in a matrix shape. For example, the first substrate712may comprise a glass substrate. A source electrode of each of the TFTs is electrically connected to a data line. A gate electrode of each of the TFTs is electrically connected to a gate line. A drain electrode of each of the TFTs is electrically connected to a pixel electrode that comprises a transparent conductive material.

The second substrate714may comprise a color filter substrate. For example, the second substrate714may comprise a glass substrate. The second substrate714has a common electrode (not shown) that comprises a transparent conductive material.

When electric power is applied to the gate electrode of each of the TFTs, the TFT is turned on and an electric field is formed between the pixel electrode (not shown) and the common electrode (not shown). Therefore, an orientation of the liquid crystals in the liquid crystal layer716between the first and second substrates712and714is changed by the electric field applied to the liquid crystal layer716. Thus, a light transmittance of the liquid crystal layer716is changed, thereby causing an image having a predetermined gray-scale to be displayed.

The driving circuit member720includes a data printed circuit board (PCB)722, a gate PCB724, a data flexible circuit film726, and a gate flexible film728. The data PCB722applies a data driving signal to the LCD panel710. The gate PCB724applies a gate driving signal to the LCD panel. The data flexible circuit film726electrically connects the data PCB722to the LCD panel710. The gate flexible circuit film728electrically connects the gate PCB724to the LCD panel710. Each of the data and gate flexible circuit films726and728may comprise a tape carrier package (TCP) or a chip on film (COF).

The data flexible circuit film726is bent so that the data PCB722is positioned along a side surface or a rear surface of the receiving container830. The gate flexible circuit film728is also bent so that the gate PCB724is positioned along the side surface or the rear surface of the receiving container830. Alternatively, an auxiliary signal line is formed on the LCD panel710and the gate flexible circuit film728so that the gate PCB724may be omitted.

The LCD device600further includes a light diffusion plate810and at least one optical sheet820. The light diffusion plate810is positioned on the flat-type fluorescent lamp100to diffuse the light generated by the flat-type fluorescent lamp100. The optical sheet820is positioned on the diffusion plate810.

The diffusion plate810diffuses the light generated from the flat-type fluorescent lamp100to create a uniform luminance of light. The diffusion plate810comprises a plate shape having a predetermined thickness. The diffusion plate810is spaced apart from the flat-type fluorescent lamp100by a predetermined distance. The diffusion plate810comprises a transparent material and a diffusing agent. In this exemplary embodiment, the diffusing agent comprises polymethyl methacrylate (PMMA).

The optical sheet820guides a light path of the light that has passed through the diffusion plate810. The optical sheet820may comprise a bright enhancement film (BEF) that improves a luminance when viewed from a front of the LCD panel700. Alternatively, the optical sheet820may further comprise a diffusion sheet for further diffusing the diffused light that has passed through the diffusion plate810. The LCD device600may further include various optical sheets.

The LCD device600may further include a cushioning member840interposed between the flat-type fluorescent lamp100and the receiving container830to support the flat-type fluorescent lamp100. The cushioning member840is positioned adjacent to sides of the flat-type fluorescent lamp100so that the flat-type fluorescent lamp100is spaced apart from the receiving container830by a predetermined distance, thereby electrically insulating the flat-type fluorescent lamp100from the receiving container830that has a metal. The cushioning member840contains insulating material. In addition, the cushioning member840may comprise an elastic material. For example, the cushioning member840may comprise silicon. In this exemplary embodiment, the cushioning member840comprises two U-shaped pieces. Alternatively, the cushioning member840may comprise four linear pieces corresponding to the four sides of the flat-type fluorescent lamp100. The cushioning member840may comprise four L-shaped pieces corresponding to four corners of the flat-type fluorescent lamp100, respectively. Alternatively, the cushioning member840may comprise one frame shaped cushioning member840.

The LCD device600may further include a first molded frame850interposed between the flat-type fluorescent lamp100and the diffusion plate810.

The first molded frame850fixes sides of the flat-type fluorescent lamp100, and supports sides of the diffusion plate810. In this exemplary embodiment, the first molded frame850has a frame shape. Alternatively, the first molded frame850may comprise two U-shaped pieces, two L-shaped pieces corresponding to corners of the flat-type fluorescent lamp100, or four linear pieces corresponding to the sides of the flat-type fluorescent lamp100.

The LCD device600may further include a second molded frame860interposed between the optical sheet820and the LCD panel710. The second molded frame860fixes sides of the optical sheet820and the diffusion plate810, and supports the sides of the LCD panel710. In this exemplary embodiment, the second molded frame860has a frame shape. Alternatively, the second molded frame860may comprise two U-shaped pieces, two L-shaped pieces, or four pieces corresponding to the sides of the flat-type fluorescent lamp100.

The LCD device600may further include a top chassis870to fix the display unit700. The top chassis870is combined with the receiving container830to fix the sides of the LCD panel710. The data PCB722is bent by the data flexible circuit film726to be fixed on the sidewalls or the bottom plate of the receiving container830. The top chassis870may comprise a strong metal.

In accordance with the present invention, the first external electrode comprise an auxiliary electrode portion on the outermost discharge spaces so that the luminance of the outer discharge spaces is increased, thereby providing luminance uniformity for the display and improving an image display quality of the flat-type fluorescent lamp.

In addition, the floating electrode member is formed on the outer discharge spaces so that the flat-type fluorescent lamp may be operated at a low temperature.

Furthermore, the first external electrode may comprise a second auxiliary electrode portion to enhance performance of the flat-type fluorescent lamp.

This invention has been described with reference to the exemplary embodiments. It is evident, however, that many alternative modifications and variations will be apparent to those having skill in the art in light of the foregoing description. Accordingly, the present invention embraces all such alternative modifications and variations which fall within the spirit and scope of the appended claims.