Patent Publication Number: US-2006018128-A1

Title: Flat-type light source device and liquid crystal display device having the same

Description:
This application claims priority to Korean Patent Application No. 2004-58211 filed on Jul. 26, 2004 and all the benefits accruing therefrom under 35 U.S.C. §119, and the contents of which in its entirety are herein incorporated by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a flat-type light source device and a liquid crystal display (“LCD”) device having the flat-type light source device. More particularly, the present invention relates to a flat-type light source device capable of supplying a light to an LCD panel, and an LCD device having the flat-type light source device.  
      2. Description of the Related Art  
      An LCD device, in general, displays an image by using liquid crystal. The LCD device is one type of flat panel display devices. The LCD device has various characteristics, such as a thin thickness, a lightweight structure, a low driving voltage, and low power consumption. Therefore, the LCD device has been used in various fields.  
      An LCD panel of the LCD device emits no light by itself, therefore the LCD panel requires a backlight assembly to provide the LCD panel with light.  
      The backlight assembly, in general, includes a cold cathode fluorescent lamp (“CCFL”) as a light source. The backlight assembly including the CCFL as the light source is classified into an edge illumination type backlight assembly and a direct illumination type backlight assembly according to the position of the light source.  
      In the edge illumination type backlight assembly, one or two lamps are disposed at side portions of a light guide plate having a reflecting layer, so that light generated from the lamp or lamps enters the light guide plate through a side face of the light guide plate and is reflected by the reflecting layer to advance toward the LCD panel.  
      In the direct illumination type backlight assembly, lamps are disposed under the light guide plate facing a light entering face of the light guide plate, a reflection plate is disposed under the lamps, and a diffusion plate is disposed on the light exiting face of the light guide plate to enhance luminance uniformity. Light generated from the lamps enters through the light entering face of the light guide plate, exits the light exiting face of the light guide plate, and is diffused by the diffusion plate.  
      A backlight assembly has various demerits such as low light-using efficiency, complex structure, high manufacturing cost, and non-uniform luminance due to light loss caused by an optical member such as the light guide plate and the diffusion plate.  
      Therefore, a flat-type light source device has been developed to solve the above-mentioned problems. The flat-type light source device has low manufacturing cost, and requires only one inverter to generate the surface light. The flat-type light source device includes an electrode for applying a discharge voltage to a plurality of discharge spaces formed by combining an upper substrate with a lower substrate. When a discharge voltage is applied to discharge gas in the discharge spaces, ultraviolet light is generated. The ultraviolet light generated from the discharge gas is converted into visible light by a fluorescent layer formed on an inner surface of one of the upper substrate and the lower substrate.  
      In addition, the electrode may be classified into an external electrode and an internal electrode. The external electrode is formed on an outer surface of the upper substrate or the lower substrate, and the internal electrode is formed on an inner surface of the upper substrate or the lower substrate. The external electrode may be easily electrically coupled to the inverter, however the flat-type light source device having the internal electrode requires a space for exposing the internal electrode so that the internal electrode Is electrically coupled to the inverter. Therefore, a size of a peripheral region of the flat-type light source device having the internal electrode, which emits no light, increases.  
     BRIEF SUMMARY OF THE INVENTION  
      The present invention provides a flat-type light source device capable of reducing a size of the peripheral region.  
      The present invention also provides an LCD device having the above-mentioned flat-type light source device.  
      An exemplary embodiment of a flat-type light source device according to the present invention includes a first substrate, an electrode, and a second substrate. The first substrate has a flat-plate shape. The electrode is formed on the first substrate. The second substrate is combined with the first substrate to form a discharge space, and has a connection portion. A portion of the electrode is exposed through the connection portion.  
      The second substrate includes a plurality of discharge space portions, a plurality of space division portions, and a sealing portion. The discharge space portions are spaced apart from the first substrate to form the discharge spaces. The space division portions are formed between adjacent discharge space portions so that the space division portions make contact with the first substrate. The sealing portion is formed on a peripheral portion of the discharge space portions and the space division portions to be combined with the first substrate.  
      One of the discharge space portions, which is adjacent to the sealing portion, has a recess. The recess is formed adjacent to an end portion of the second substrate to expose the electrode via the connection portion positioned at the recess. The end portion of the second substrate is substantially parallel to a longitudinal direction of the discharge space portion. A connection hole is formed through the second substrate that is partially exposed through the recess. In addition, the recess corresponds to the electrode.  
      The connection portion is a contact hole formed through the second substrate that is partially exposed through the recess. Also, in order to form the connection portion, the sealing portion and the second substrate that is partially exposed through the recess corresponding to the electrode are partially removed.  
      An exemplary embodiment of an LCD device according to the present invention includes a flat-type light source device, a liquid crystal display panel, and an inverter.  
      The flat-type light source device includes a first substrate, an electrode formed on the first substrate, and a second substrate combined with the first substrate to form a plurality of discharge spaces. The second substrate has a connection portion through which a portion of the electrode is exposed.  
      The LCD panel displays an image by using a light generated from the flat-type light source device.  
      The inverter generates a discharge voltage for operating the flat-type light source device, and is electrically coupled to the electrode through the connection portion.  
      Also, the LCD device further includes a receiving container to receive the flat-type light source device, a diffusion plate between the flat-type light source device and the liquid crystal display panel, and a fixing member to fix the liquid crystal display panel to the receiving container.  
      In another exemplary embodiment, a flat-type light source device includes an electrode and a substrate having a first surface contacting the electrode and an opposite second surface, the substrate Including an aperture exposing a section of the electrode, the aperture passing through the first surface to the second surface. Therefore, the electrode is exposed to the exterior of the flat-type light source device through the connection portion formed on the second substrate so that the electrode is electrically coupled to the inverter. In addition, a size of the flat-type light source device decreases. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The above and other advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the accompanying drawings, in which:  
       FIG. 1  is an exploded perspective view showing an exemplary embodiment of a flat-type light source device according to the present invention;  
       FIG. 2  is a cross-sectional view showing the exemplary flat-type light source device of  FIG. 1 ;  
       FIG. 3  is a plan view showing the exemplary flat-type light source device of  FIG. 1 ;  
       FIG. 4  is a perspective view showing an exemplary recess and an exemplary connection portion shown in  FIG. 1 ;  
       FIG. 5  is a cross-sectional view taken along line I-I′ in  FIG. 4 ;  
       FIG. 6  is a perspective view showing an exemplary first substrate of  FIG. 1 ;  
       FIG. 7  is a perspective view showing a portion of the exemplary first substrate of  FIG. 6 ;  
       FIG. 8  is an enlarged view of portion ‘A’ in  FIG. 1 ;  
       FIG. 9  is a cross-sectional view taken along line II-II′ in  FIG. 8 ;  
       FIG. 10  is a perspective view showing another exemplary embodiment of a connection portion according to the present invention;  
       FIG. 11  is a cross-sectional view taken along line III-III′ in  FIG. 10 ;  
       FIG. 12  is an exploded perspective view showing another exemplary embodiment of a flat-type light source device according to the present invention;  
       FIG. 13  is a perspective view showing an exemplary electrode of  FIG. 12 ;  
       FIG. 14  is a cross-sectional view taken along line IV-IV′ in  FIG. 12 ; and  
       FIG. 15  is an exploded perspective view showing an exemplary embodiment of an LCD device according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      It should be understood that the exemplary embodiments of the present invention described below 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 following embodiments. Rather, these embodiments are provided so that this disclosure will be through and complete, and will fully convey the concept of the invention to those skilled in the art by way of example and not of limitation.  
      Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the thickness of layers, films, and regions are exaggerated for clarity. Like numerals refer to like elements throughout. It will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present.  
       FIG. 1  is an exploded perspective view showing an exemplary embodiment of a flat-type light source device according to the present invention.  FIG. 2  is a cross-sectional view showing the exemplary flat-type light source device of  FIG. 1 .  
      Referring to  FIGS. 1 and 2 , the flat-type light source device  100  includes a first substrate  110 , a pair of electrodes  120 , and a second substrate  130 . The first substrate  110  has a flat-plate shape, such as a shape having a rectangularly shaped periphery and opposing flat faces, although other shapes are within the scope of these embodiments. The electrodes  120  are formed on end portions of the first substrate  110 . The electrodes  120  are spaced apart from each other. For example, as illustrated, a first electrode  120  is positioned on a first face of the first substrate  110  adjacent a first end of the first substrate  110 , and a second electrode  120  is also positioned on the first face but adjacent a second end of the first substrate  110 , opposite the first end. The second substrate  130  is combined with the first substrate  110  to form a plurality of discharge spaces  140 , and has a connection portion  135 . Alternatively, the first and second substrates  110  and  130  may form only one discharge space  140 . A portion of the electrodes  120  is exposed through the connection portion  135 .  
      The first substrate  110  has a rectangular flat-plate shape. A glass substrate that transmits visible light and blocks ultraviolet light may be employed as the first substrate  110 . While a particular shape and material is described for the first substrate  110 , alternate shapes and materials with similar properties would also be within the scope of these embodiments.  
      The electrodes  120  are disposed such that a longitudinal direction of the electrodes  120  is substantially perpendicular to a longitudinal direction of the discharge spaces  140 . The electrodes  120  are overlapped by end portions of the discharge spaces  140 . Each of the electrodes  120  has a width EW, measured in a direction parallel to a longitudinal direction of the discharge spaces  140 . The electrodes  120  are formed by spraying a conductive material, such as a metallic powder, for example, Cu, Ni, Ag, Au, Al, Cr or a mixture thereof on the first substrate  110 . In particular, a mask exposing an area for the electrodes  120  is disposed on the first substrate  110 , and the metallic powder is sprayed onto the area to be coated. Then, the mask is removed to form the electrodes  120 . Alternatively, the electrodes  120  may be formed on the first substrate  110  by various other methods.  
      The second substrate  130  is combined with the first substrate  110  to form a plurality of discharge spaces  140 . A glass substrate that transmits visible light and blocks ultraviolet light may be employed as the second substrate  130 , although other materials with similar properties would also be within the scope of these embodiments. The second substrate  130  comprises a plurality of discharge space portions  131 , a plurality of space division portions  132 , and a sealing portion  133 . Each of the discharge space portions  131  is spaced apart from the first substrate  110  to form each of the discharge spaces  140  between the discharge space portions  131  and the first substrate  110 . The space division portions  132  are formed between adjacent discharge space portions  131 , and make contact with the first substrate  110 . The sealing portion  133  is formed on an outer peripheral portion of the second substrate  130 . The first and second substrates  110  and  130  may be combined with each other through an adhesive member disposed between the first and second substrates in the sealing portion  133 .  
      In this embodiment, one of the outermost discharge space portions  131  has a recess  134  adjacent each longitudinal end of the discharge space portion  131 . Each recess  134  is formed at an end portion of the second substrate  130  to be disposed over the electrodes  120 . In particular, two recesses  134  are formed on the second substrate  130  to expose the electrodes  120 , respectively. The two recesses  134  may be diagonally disposed, such as by providing one recess  134  in one corner of the second substrate  130  and another recess  134  in a diagonally opposite corner of the second substrate  130 , where one recess  134  would be provided on a first outermost discharge space portion  131 , and a second recess  134  would be provided on a second outermost discharge space portion  131  on a opposite side of the second substrate  130 . Alternatively, as illustrated, the two recesses  134  may be disposed along a longitudinal direction of the second substrate  130 .  
      The recesses  134  are disposed over each of the electrodes  120 . The connection portion  135  is formed at each of the recesses  134 . The connection portion  135  corresponds to a contact hole that exposes a portion of the electrodes  120 . In the illustrated exemplary embodiment, the contact hole has a circular shape, when viewed on a plane. The first substrate  110  is combined with the second substrate  130 , and a portion of the electrode  120  is exposed through the connection portion  135 .  
      Alternatively, the electrodes  120  may be formed on the inner surface of the second substrate  130 . When the electrodes  120  are formed on the inner surface of the second substrate  130 , the connection portion  135  is formed at the first substrate  110 .  
      The second substrate  130  is formed, for example, through a molding process, where a plate-shaped base substrate is heated and compressed using a mold to form the second substrate having the discharge space portions  131 , the space division portions  132 , the sealing portion  133 , and the recesses  134 .  
      The connection portion  135  may be formed through various ways. For example, the connection portion  135  may be formed through a mechanical drilling or a laser drilling. The connection portion  135  may have various shapes such as a circular shape, a rectangular shape, a polygonal shape, etc., when viewed on a plane.  
      As shown in  FIG. 2 , each of the discharge spaces  140  has a trapezoidal shape having rounded corners. Alternatively, the cross-section of each of the discharge spaces  140  may have various shapes such as a semi-circular shape, a rectangular shape, etc.  
      The second substrate  130 , is combined with the first substrate  110 , for example, through an adhesive member  150  such as a frit. The frit is a mixture of a glass and a metal, and has a melting point lower than that of the glass of the first and second substrates  110  and  130 . The frit is then sintered to form the adhesive member  150 . The adhesive member  150  is placed on the sealing portion  133  between the first and second substrates  110  and  130 . The adhesive member  150  is not disposed along the space division portions  132  where the space division portions  132  make contact with the first substrate  110 . The space division portions  132  make contact with the first substrate  110  by a pressure difference between the discharge spaces  140  and exterior surroundings of the flat-type light source device  100 . In particular, after combining the first substrate  110  with the second substrate  130 , an air in the discharge spaces  140  is exhausted so as to be in a vacuum state, and then discharge gas for a plasma discharge is injected into the discharge spaces  140 . For example, the discharge gas may include mercury (Hg), neon (Ne), argon (Ar), xenon (Xe), krypton (Kr), a mixture thereof, etc. A pressure of the discharge gas in the discharge spaces  140  is about 50 Torr, while the atmospheric pressure outside of the flat-type light source device  100  is 760 Torr. Therefore, a pressure difference is generated between the discharge spaces  140  and the outside of the flat-type light source device  100  so that the space division portions  132  make contact with the first substrate  110 .  
      A connection passage  160  is formed at the second substrate  130  to connect the discharge spaces  140  that are adjacent to each other. At least one connection passage  160  is formed at each of the space division portions  132 . The discharge gas injected into the discharge spaces  140  may move between the discharge spaces  140  through the connection passages  160  so that the discharge gas may be uniformly distributed in discharge spaces  140 , thereby uniformizing pressure distribution in the discharge spaces  140 .  
      The flat-type light source device  100  further includes a reflective layer  112  formed on an upper surface, the first face, of the first substrate  110 , a first fluorescent layer  114  formed on the reflective layer  112 , and a second fluorescent layer  116  formed on a lower surface of the second substrate  130  corresponding to the discharge space portions  131 . That is, the first fluorescent layer  114  is formed on a surface of the first substrate  110  that faces the second substrate  130 , and the second fluorescent layer  116  is formed on a surface of the second substrate  130  that faces the first substrate  110 .  
      The reflective layer  112  is formed on the first face of the first substrate  110  except for a region corresponding to the electrodes  120  that are also disposed on the first face of the first substrate  110 . The reflective layer  112  is disposed between the electrodes  120 . In this exemplary embodiment, the reflective layer  112  is not formed on the area corresponding to the sealing portion  133 , so that an adhesive strength between the adhesive member  150  and the first substrate  110  may be increased. Visible light generated from the first fluorescent layer  114  and the second fluorescent layer  116  is reflected by the reflective layer  112  toward the second substrate  130  to prevent a light leakage.  
      The first fluorescent layer  114  is formed on the reflective layer  112 , and has a substantially same area as the reflective layer  112 . That is, the first fluorescent layer  114  is formed on the reflective layer  112 , and not on the region corresponding to the electrodes  120  and the sealing portion  133 . The first fluorescent layer  114  is formed between the electrodes  120 . The second fluorescent layer  116  is formed on a surface of the second substrate  130  that faces the first substrate  110 . The second fluorescent layer  116  corresponds to the first fluorescent layer  114 . The second fluorescent layer  116  may be formed on the lower surface of the second substrate  130 , the surface that faces the first substrate  110 , except for the sealing portion  133 .  
      In this exemplary embodiment, the second fluorescent layer  116  is disposed on a surface corresponding to the discharge space portions  131 . The first and the second fluorescent layers  114  and  116  convert ultraviolet light generated from discharge gas in the discharge spaces  140  into visible light.  
      The flat-type light source device  100  may further include a protective layer (not shown). The protective layer is disposed between the second substrate  130  and the second fluorescent layer  116  and/or between the first substrate  110  and the reflective layer  112 . The protective layer prevents a chemical reaction between mercury of the discharge gas and the first substrate  110  or between mercury of the discharge gas and the second substrate  130  so that a loss of mercury or blackening phenomenon of the flat-type light source device  100  may be prevented.  
       FIG. 3  is a plan view of the flat-type light source device  100  shown in  FIG. 1 .  
      Referring to  FIG. 3 , recesses  134  are provided on the discharge space portions  131 . Each of the recesses  134  is adjacent to the sealing portion  133 . At least one recess  134  is formed at the discharge space portion  131  so as to be disposed over the electrodes  120 . In this exemplary embodiment, two recesses  134  are disposed over the electrodes  120 , respectively. As shown in  FIG. 3 , the recesses  134  are formed on one of the outermost discharge space portions  131 . The recesses  134  are formed, for example, on the same discharge space, as in the illustrated embodiment. Alternatively, one of the recesses  134  may be diagonally disposed, as previously described. Two connection portions  135  are formed at the second substrate  130 , where each of the connection portions  135  is disposed at the recesses  134 , respectively. The connection portions  135  expose a portion of the electrodes  120 .  
      In one embodiment, a width of the sealing portion  133  is only about 3 mm, so that forming the connection portion  135  at the sealing portion  133  would be difficult. Therefore, the recesses  134  are formed at the discharge space portions  131  adjacent to the sealing portion  133 , respectively, and the connection portions  135  are formed within the recessed portion  134 . As a result, a manufacturing process of the flat-type light source device may be simplified to enhance productivity thereof. In addition, an adhesive strength between the electrodes and the first and second substrates  110  and  130  increases because the sealing portion  133  is not interrupted, and a size of the flat-type light source device  100  decreases because a size of the peripheral region does not need to increase to effectively provide a connection to the internal electrodes  120 .  
       FIG. 4  is a perspective view showing an exemplary recess  134  and an exemplary connection portion  135  of  FIG. 1 .  FIG. 5  is a cross-sectional view taken along line I-I′ in  FIG. 4 .  
      Referring to  FIGS. 4 and 5 , one of the discharge space portions  131 , which is adjacent to a sealing portion  133 , has a recess  134 . The recess  134  is formed adjacent to an end portion of the second substrate  130 , corresponding to an end portion of the first substrate  110  that carries an electrode  120 . The end portion adjacent to the recess  134  is substantially parallel to the longitudinal direction of the discharge space portion  131 . It should be understood that the recess  134  is an indentation within the discharge space portion  131  and that there are no apertures formed in the discharge space portion  131  by the recess  134 . The connection portion  135  corresponds to a contact hole through which a portion of the electrodes  120  shown in  FIG. 3  is exposed. The second substrate  130  is combined with the first substrate  110  through the adhesive member  150  disposed at the sealing portion  133 . The connection portion  135  formed at the recess  134  penetrates the second substrate  130  to expose the electrodes  120 . The connection portion  135 , in the illustrated embodiment, includes a hole formed in a planar portion of the second substrate  130  located adjacent the recess  134 , such as between the recess  134  and the sealing portion  133 . The planar portion for the connection portion  135  may be coplanar with the portions of the space division portions  132  that make contact with the first substrate  110 .  
      The recess  134  may have various sizes and shapes in accordance with a required width EW of the electrode  120  and the size of the connection portion  135 . In this embodiment, the recess  134  has a smaller width than the electrode  120 , and has a larger size than the connection portion  135 .  
      In this embodiment, the flat-type light source device  100  further includes a dielectric layer  122  formed on the electrodes  120 . The dielectric layer  122  has a dielectric material to protect the electrodes  120 . The electrode  120 , the discharge space  140 , and the dielectric layer  122  disposed there between define a capacitor. The dielectric layer  122  has an opening exposing a portion of the electrode  120 , where the opening corresponds to a location of the connection portion  135  of the second substrate  130 .  
      According to this exemplary embodiment, the flat-type light source device  100  includes the connecting portion  135  so that the electrode  120  is electrically connected to a power line disposed outside of the flat-type light source device  100 . The power line may be electrically connected to the electrodes  120  through a soldering, or through other electrical connection devices.  
       FIG. 6  is a perspective view showing an exemplary first substrate  110  shown in  FIG. 1 .  FIG. 7  is a perspective view showing a portion of the exemplary first substrate  110  of  FIG. 6 .  
      Referring to  FIGS. 6 and 7 , the electrodes  120  are formed on opposite end portions of the first face of the first substrate  110 . Each of the electrodes  120  has a band-like shape having the electrode width EW. The dielectric layer  122  is formed on the electrodes  120 . The dielectric layer  122  has an opening exposing the electrodes  120 . The opening of the dielectric layer  122  corresponds to a location of the connection portion  135  of the second substrate  130 . That is, when the second substrate  130  is assembled with the first substrate  110 , the connection portion  134  is aligned with the opening in the dielectric layer  122 .  
      A reflective layer  112  is formed on the upper surface, first face, of the first substrate  110  except for a region corresponding to the electrodes  120  and the sealing portion  133 . The reflective layer  112  may be formed between the electrodes  120 . A first fluorescent layer  114  is formed on the reflective layer  112  and is also not formed on the electrodes  120 .  
      In this embodiment, a sum of a thickness of an electrode  120  and a thickness of the dielectric layer  122  is substantially the same as a sum of a thickness of the reflective layer  112  and a thickness of the first fluorescent layer  114 . In such an embodiment, the first fluorescent layer  114  lies substantially flush with the dielectric layer  122  for providing a flat surface for the second substrate  130  to be placed upon.  
      The space division portions  132  of the second substrate  130  make contact with both the dielectric layer  122  and the first fluorescent layer  114  of the first substrate  110 , when the first and second substrates  110  and  130  are combined with each other.  
      If the total thickness of the electrodes  120  and the dielectric layer  122  were different from the total thickness of the reflective layer  112  and the first fluorescent layer  114 , then a stepped portion would be generated at a boundary between the dielectric layer  122  and the first fluorescent layer  114  so that an undesirable space would be formed between the dielectric layer  122  and the space division portion  132 .  
      However, in this exemplary embodiment, the total thickness of an electrode  120  and the dielectric layer  122  is substantially the same as the total thickness of the reflective layer  112  and the first fluorescent layer  114 , so that the space division portion  132  is securely combined with the first substrate  110 . While the reflective layer  112  is illustrated as having the same thickness as the electrodes  120  and the first fluorescent layer  114  is illustrated as having the same thickness as the dielectric layer  122 , it should be understood that the reflective layer  112  may have a greater thickness than the electrodes  120  while the fluorescent layer  114  has a smaller thickness than the dielectric layer  122 , so long as the total thickness of the reflective and fluorescent layers  112 ,  114  is substantially the same as the total thickness of an electrode  120  and the dielectric layer  122 . Likewise, the reflective layer  112  may have a smaller thickness than the electrodes  120  while the fluorescent layer  114  has a greater thickness than the dielectric layer  122 , so long as the total thickness of the reflective and fluorescent layers  112 ,  114  is substantially the same as the total thickness of an electrode  120  and the dielectric layer  122 .  
       FIG. 8  is an enlarged view of portion “A” shown in  FIG. 1 .  FIG. 9  is a cross-sectional view taken along line II-II′ of  FIG. 8 .  
      Referring to  FIGS. 8 and 9 , at least one connection passage  160  is formed at each of the space division portions  132 . While most of each space division portion  132  may be substantially planer for contacting the first substrate  110 , a portion of each space division portion  132  of the second substrate  130  is spaced apart from the first substrate  110  to form the connection passage  160 , when the first and second substrates  110  and  130  are combined with each other. The connection passage  160 , for example, is curved in a diagonal direction of the space division portions  132 . In other words, the connection passage  160  may have an S-shape.  
      When the connection passage  160  has the S-shape, a length of the connection passage  160  increases so as to be longer than a width of the space division portion  132 , where a width of the space division portion  132  is measured perpendicularly with respect to a longitudinal length of the space division portions  132 . Thus, a path through which plasma flows from one of the discharge spaces  140  to an adjacent discharge space  140  becomes longer. Therefore, a drift of plasma generated by the plasma discharge is reduced.  
      The connection passage  160 , for example, is formed at a central portion of each space division portion  132 . Alternatively, the connection passages  160  may be positioned at alternating longitudinal locations of adjacent space division portions  132 . The connection passage  160  may have a width of about 2 mm and a height of about 2 mm. Alternatively, more than one connection passage  160  may be formed in each space division portion  132  and they may be evenly distributed within each space division portion  132 . The connection passage  160  may have various shapes.  
       FIG. 10  is a perspective view showing another exemplary embodiment of a connection portion according to the present invention.  FIG. 11  is a cross-sectional view taken along line III-III′ of  FIG. 10 . In this embodiment, the flat-type light source device  200  shown in  FIGS. 10 and 11  is substantially the same as the flat-type light source device  100  shown in FIGS.  1  to  9  except for the connection portion. Thus, the same reference numerals will be used to refer to the same or like parts as those described in FIGS.  1  to  9  and any further explanation will be omitted.  
      Referring to  FIGS. 10 and 11 , a connection portion  235  in the flat-type light source device  200  is formed by removing a portion of a sealing portion  133  to expose a portion of the electrodes  120 . in this embodiment, the sealing portion  133  corresponding to the connection portion  235  is removed so that a portion of the electrodes  120  is exposed through the connection portion  235 . The removed portion that defines the connection portion  235  may extend at least partially into the area defined by the recess  134 .  
      An adhesive member  150  is disposed at the sealing portion  133  except for a region corresponding to the connection portion  235  to combine a first substrate  110  with a second substrate  130 . The adhesive member  150  is also disposed between the first substrate  110  and a perimeter of the recess  134  of the second substrate  130  for sealing all edges of the second substrate  130  to the first substrate  110 .  
      In this embodiment, each of the electrodes  120  is extended to the sealing portion  133 . A dielectric layer  122  is formed on each electrode  120  except for regions corresponding to the connection portions  235 . In other words, an end portion of each electrode  120 , in an area located below the connection portion  235 , is not covered by the dielectric layer  122 .  
      The flat-type light source device  200  further comprises a conductive clip  210 . The conductive clip  210  may include a generally U-shaped cross-section, where a first leg of the conductive clip  210  makes contact with the electrode  120 , a second leg of the conductive clip  210  makes contact with a lower surface of the first substrate  110 , and a connecting portion of the conductive clip  210  connects the first leg to the second leg. The conductive clip  210  is coupled to the first substrate  110  at the position corresponding to the connection portion  235 . When the conductive clip  210  is coupled to the first substrate  110 , an inner portion of the first leg of the conductive clip  210  makes contact with the electrode  120  that is exposed through the connection portion  235 . In order to decrease a size of the flat-type light source device  200 , for example, the sealing portion  133  has a width of about  3  mm, and the connection portion  235  is extended toward the recess  134  and past the sealing portion  133  so that the conductive clip  210  may be stably combined with the first substrate  110 . The conductive clip  210  may further include a coupling terminal  212  for being coupled to an external power line. The coupling terminal  212  may extend from the connecting portion of the conductive clip  212  and may include a pair of curved power line holders for holding a power line there between. When the conductive clip  210  has the coupling terminal  212 , an additional process such as a soldering to connect the power line may be omitted.  
       FIG. 12  is an exploded perspective view of another exemplary embodiment of a flat-type light source device according to the present invention.  FIG. 13  is a perspective view showing an exemplary electrode shown in  FIG. 12 .  FIG. 14  is a cross-sectional view taken along line IV-IV′ of  FIG. 12 . In this embodiment, the flat-type light source device  300  shown in FIGS.  12  to  14  is similar to the flat-type light source devices  100  and  200  shown in FIGS.  1  to  11 . Thus, the same reference numerals will be used to refer to the same or like parts as those described in FIGS.  1  to  11  and any further explanation will be omitted.  
      Referring to FIGS.  12  to  14 , the flat-type light source device  300  includes electrodes  320 , a dielectric layer  322 , a reflective layer  312 , and a first fluorescent layer  314  formed on a first substrate  110 .  
      As shown in  FIG. 13 , the electrodes  320  are formed on opposite end portions of the first substrate  110 . Each of the electrodes  320  is extended in a direction that is substantially perpendicular to a longitudinal direction of each of the discharge space portions  132 . Each of the electrodes  320  is overlapped by the discharge space portions  131 . Each of the electrodes  320  has a first width EW 1  corresponding to the space division portions  132  and a second width EW 2  corresponding to the discharge space portions  131 . That is, when the second substrate  130  is assembled onto the first substrate  110 , end portions of the space division portions  132  overlie the electrodes  320  in areas having the first width EW 1 , and end portions of the discharge space portions  131  overlie the electrodes  320  in areas having the second width EW 2 . The second width EW 2  is different from the first width EW 1 . In this embodiment, the first width EW 1  is less than the second width EW 2 . For example, the first width EW 1  is in a range of about 1 to about 2 mm, and the second width EW 2  is in a range of about 10 to about 15 mm. Thus, more surface area of the electrodes  320  is located within areas corresponding to the discharge space portions  131  where it is employed to apply voltage to discharge areas  140 , and less surface area of the electrodes  320  is located within areas corresponding to the space division portions  132  where the voltage is not necessary other than to pass on the discharge voltages to areas of the electrode  320  having the second width EW 2 .  
      A dielectric layer  322  is disposed on the electrodes  320 . The dielectric layer  322  is partially opened, such as via an aperture, so that a portion of the electrode  320  is exposed through the opening of the dielectric layer  322 . Alternatively, the connection portion  135  may be replaced by the connection portion  235 , and a conductive clip may be utilized, as previously described.  
      A reflective layer  312  is disposed on the first substrate  110  except for an area corresponding to the electrodes  320  and the sealing portion  133  of the second substrate  130 . The reflective layer  312  may be disposed between the electrodes  320 . A first fluorescent layer  314  is disposed on the reflective layer  312 .  
      In this embodiment, when the first substrate  110  is combined with the second substrate  130 , the space division portions  132  make contact with the first fluorescent layer  314 . The reflective layer  312  and the first fluorescent layer  314  that is disposed on the reflective layer  312  are disposed on the first substrate  110  corresponding to the space division portions  132 . Each of the first and second widths EW 1  and EW 2  are small with respect to a length of the first substrate  110 , so a total thickness of the flat-type light source device  300  may be determined regardless of a lack of electrode material in certain areas containing the electrode  320  having the first width EW 1  of the first substrate  110  so that the flat-type light source device  300  is still considered to have uniform thickness. Therefore, the space division portions  132  make contact with the first fluorescent layer  314 . In this embodiment, as in the previous embodiment, a total thickness of each of the electrodes  320  and the dielectric layer  322  is substantially the same as a total thickness of the reflective layer  312  and the first fluorescent layer  314 , thus providing a substantially flat surface for the second substrate  130  to be placed upon.  
       FIG. 15  is an exploded perspective view showing an exemplary embodiment of an LCD device according to the present invention. A flat-type light source device  100  shown in  FIG. 15  is substantially the same as the light source devices described with respect to FIGS.  1  to  14 . Thus, the same reference numerals will be used to refer to the same or like parts as those described in FIGS.  1  to  14  and any further explanation will be omitted. While the flat-type light source device  100  is shown in  FIG. 15 , it should be understood that any of the above described embodiments, or combinations thereof, of a flat-type light source device described with respect to  FIGS. 1-14  may be employed in the LCD device  400 .  
      Referring to  FIG. 15 , the LCD device  400  includes, in part, the flat-type light source device  100 , a display unit  500 , and an inverter  600 .  
      The display unit  500  includes an LCD panel  510 , a data printed circuit board (“PCB”)  520 , and a gate PCB  530 . The data and gate PCBs  520  and  530  generate driving signals to drive the LCD panel  510 . Driving signals generated from the data and gate PCBs  520  and  530  are applied to the LCD panel  510  through a data flexible circuit film  540  and a gate flexible circuit film  550 . For example, a tape carrier package (“TCP”) or a chip on film (“COF”) may be employed as the data and gate flexible circuit film  540 ,  550 . Also, the data and gate flexible circuit films  540  and  550  further comprise a data driving chip  542  and a gate driving chip  552  controlling the driving signals, respectively, to apply the driving signals to the LCD panel  510  at a proper time.  
      The LCD panel  510  includes a thin film transistor (“TFT”) substrate  512 , a color filter substrate  514 , and a liquid crystal layer  516 . The color filter substrate  514  faces the TFT substrate  512 . The liquid crystal layer  516  is disposed between the TFT substrate  512  and the color filter substrate  514 .  
      Although not illustrated in detail for clarity, the LCD panel  510  may function in a manner as will now be described. The TFT substrate  512  has a transparent glass plate and a plurality of switching devices arranged in a matrix shape. Each of the switching devices may be a TFT formed on the transparent glass plate. A source electrode of the TFT is electrically connected to one of a plurality of data lines. A gate electrode of the TFT is electrically connected to one of a plurality of gate lines. A drain electrode of the TFT is electrically connected to a pixel electrode.  
      The color filter substrate  514  includes a transparent plate, a red color filter, a green color filter, and a blue color filter. The red, green, and blue color filters are formed on the transparent plate through a photolithography process, a photo process, etc. The common electrode is formed on the transparent plate having the red, green, and blue color filters formed thereon. The common electrode includes an optical transparent and electrically conductive material, such as, but not limited to, indium zinc oxide (“IZO”), indium tin oxide (“ITO”).  
      When voltages are applied to the gate and source electrodes of the TFT, the TFT is turned on so that an electric field is generated between the pixel electrode of the TFT substrate  512  and the common electrode of the color filter substrate  514 . The arrangement of liquid crystal molecules of the liquid crystal layer  516  is varied in response to the electric field applied thereto, and thus an optical transmittance of the liquid crystal  516  may be altered, thereby displaying the image.  
      An inverter  600  generates a discharge voltage to operate the flat-type light source device  100 . The inverter  600  inverts alternating voltage from an exterior of the LCD device  400  into discharge voltages to operate the flat-type light source device  100 . The discharge voltages generated from the inverter  600  are applied to the electrodes  120  of the flat-type light source device  100  through a first power supply line  610  and a second power supply line  620 . The first and second power supply lines  610  and  620  are electrically connected to the electrodes  120  that are exposed through the connection portion  135 , by using a method such as a soldering. When the electrodes  120  are electrically connected to conductive clips  210 , the first and second power supply lines  610  and  620  are electrically connected to the conductive clips  210 , such as through the coupling terminal  212 .  
      The LCD device  400  further includes a receiving container  700  for receiving the flat-type light source device  100 , an optical member  800  for increasing a luminance of a light generated from the flat-type light source device  100 , and a fixing member  900  for fixing the LCD panel  510  with respect to the receiving container  700 .  
      The receiving container  700  includes a bottom plate  710  and a plurality of sidewalls  720 . The bottom plate  710  receives the flat-type light source device  100 . The sidewalls  720  are protruded upwardly from sides of the bottom plate  710  to form a receiving space. The receiving container  700  may further include an insulating member (not shown) for insulating the flat-type light source device  100 .  
      The optical member  800  is disposed between the flat-type light source device  100  and the LCD panel  510 . When the light generated from the flat-type light source device  100  passes through the optical member  800 , the luminance of the light increases and is uniformized. The optical member  800  includes a diffusion plate  810  for diffusing the light generated from the flat-type light source device  100 . The diffusion plate  810  has a plate-shape having a regular thickness. The diffusion plate  810  is spaced apart from the flat-type light source device  100  by a predetermined distance. The optical member  800  may further include at least one prism sheet  820  on the diffusion plate  810 . The prism sheet  820  guides the light generated from the diffusion plate  810  toward the LCD panel  510  to enhance the brightness of the light when viewed from a front of the LCD panel  510 . Alternatively, the optical member  800  may further include a diffusion sheet on the prism sheet  820  to diffuse the light. The application of more or less optical sheets within the backlight assembly would also be within the scope of these embodiments.  
      The fixing member  900  is combined with the receiving container  700 . The fixing member  900  covers sides of the LCD panel  510  to fix the LCD panel  510  on the optical member  800 . The fixing member  900  protects the LCD panel  510  from an impact that may occur on an exterior of the LCD panel  510 , and also prevents a drifting of the LCD panel  510  relative to the optical member  800  and light source device  100 .  
      The LCD device  400  may further include a fixing means (not shown) for fixing the flat-type light source device  100  within the receiving container  700  and the optical member  800  on the receiving container  700  and for guiding the LCD panel  510  onto the receiving container  700 .  
      According to the present invention, the flat-type light source device includes the recess for the connection portion at the discharge space portion that is adjacent to the sealing portion so that the inverter is electrically coupled to the electrodes. In addition, the size of the flat-type light source device may decrease.  
      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 skilled in the art in light of the foregoing description. Accordingly, the present invention embraces all such alternative modifications and variations as fall within the spirit and scope of the appended claims. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.