Patent Document

CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to and the benefit of Korean Patent Application No. 10-2013-0134394 filed in the Korean Intellectual Property Office on Nov. 6, 2013, the entire contents of which are incorporated herein by reference. 
       BACKGROUND 
       [0002]    (a) Field 
         [0003]    The present disclosure of invention relates to a backlighting assembly and a liquid crystal display (LCD) using the same, and more particularly, to a combination of a backlighting assembly and a liquid crystal display in which an adhesive member is disposed between point light sources provided on a flexible printed circuit board. 
         [0004]    (b) Description of Related Technology 
         [0005]    A liquid crystal display assembly typically includes a liquid crystal display module including a liquid crystal panel on which a to be displayed image is electronically formed, a flexible printed circuit board (FPCB) provided at an end of the liquid crystal panel, and a backlighting assembly (or “backlight assembly” for short) disposed at a bottom surface of the liquid crystal panel and configured to supply backlighting light to the panel. The LCD assembly typically further includes a bottom chassis which supports the bottom surface of the crystal display module, and a top case fastened to the bottom chassis to secure the liquid crystal display module. 
         [0006]    The liquid crystal panel and the backlight assembly may be accommodated at a side portion of a main support structure (or “main support” for short) in which the FPCB having a plurality of light emitting diodes (LEDs) provided thereon is disposed. The main support structure may be formed of a frame mold material having a generally quadrangular shape. In addition to the supported FPCB with its LEDs, the side portion of a main support structure is configured to accommodate a light guide plate (LGP) and one or more optical sheets that are to be disposed in a predetermined relationship relative to the FPCB-mounted LEDs. 
         [0007]    The FPCB having the LEDs may be fixed onto the side portion of the main support by using a fixing tape. Also, a double-sided light blocking tape may be provided between the liquid crystal panel and the backlight assembly for affixing together the liquid crystal panel and the backlight assembly. 
         [0008]    An end of the FPCB opposite to where the LEDs are mounted may be rotated by 180 degrees (e.g., into a U-shaped configuration) and electrically connected to a backlight driving driver provided at a bottom surface of the backlight unit. 
         [0009]    It is desirable to do all of the above in an economical and form factor minimizing way while assuring that the light guide plate (LGP) and the light blocking tape remain in a predetermined relationship relative to the FPCB-mounted LEDs even as the end of the FPCB is bent for connection to the backlight driving drive electronics. 
         [0010]    It is to be understood that this background of the technology section is intended to provide useful background for understanding the here disclosed technology and as such, the technology background section may include ideas, concepts or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to corresponding invention dates of subject matter disclosed herein. 
       SUMMARY 
       [0011]    The present disclosure of invention provides a combination of a backlight assembly and a liquid crystal display that is configured for reducing an undesired light leakage phenomenon by disposing a double-sided adhesive member between a plurality of light emitting diodes located in a flexible printed circuit board but leaving a discontinuity of the material of the adhesive member along high-intensity light emitting pathways of the LEDs. 
         [0012]    Further, the present disclosure of invention provides a method of adhering together a panel and a light guide by using one adhesive member to thereby simplify a manufacturing process of a liquid crystal display. 
         [0013]    An exemplary embodiment provides a backlight assembly including: a plurality of light emitting diodes (LEDs) configured to emit light; a flexible printed circuit board (FPCB) on which the LEDs are mounted; a light guide disposed to have a surface corresponding to light emitting surfaces of the LEDs; a main support configured to accommodate the LEDs and the light guide therein; and a double-sided adhesive member formed to affix together the FPCB, the main support, and the light guide, wherein one surface of the adhesive member is attached to the FPCB and another adhesive surface thereof is attached to the main support and the light guide, and the adhesive member is formed between the LEDs but not long the high-intensity light emitting pathways of the LEDs. 
         [0014]    The adhesive member may not be formed at a first region through which light emitted from the LEDs pass and a second region that is located opposite to the first region. 
         [0015]    The adhesive member may be formed to have a quadrangular, trapezoidal, triangular, or circular shape. 
         [0016]    The adhesive member may be entirely formed as stripes in a vertically longitudinal direction on a bottom surface of the FPCB. 
         [0017]    One portion of the adhesive member may be brought into contact with an upper surface of a side of the main support, and another portion thereof may be brought into contact with an upper surface of a side of the light guide. 
         [0018]    The adhesive member may be partially formed in a vertically longitudinal direction as strips on a bottom surface of the FPCB. 
         [0019]    The adhesive member may be a pre-patterned double-sided tape or a printed-on and curable fluid adhesive. 
         [0020]    Another exemplary embodiment provides a liquid crystal display including: a liquid crystal panel; a plurality of light emitting diodes (LEDs) configured to emit light; a flexible printed circuit board (FPCB) in which the LEDs are mounted; a light guide disposed to have a surface corresponding to light emitting surfaces of the LEDs; a main support configured to accommodate the LEDs and the light guide therein; and an adhesive member formed to fix the FPCB, the main support, the light guide, and the liquid crystal panel, wherein one surface of the adhesive member formed on a bottom surface of the FPCB is attached to the bottom surface of the FPCB, the other surface thereof is attached to the main support and the light guide, and the adhesive member is formed between the LEDs, and wherein the adhesive member covers a side surface and a top surface of the FPCB. 
         [0021]    The adhesive member may be formed as a folded over single unit on a top surface and a bottom surface of the FPCB. 
         [0022]    The adhesive member formed on the bottom surface of the FPCB may be formed to have a triangular, quadrangular, or circular shape. 
         [0023]    One surface of the adhesive member formed on the top surface of the FPCB may be attached to the top surface of the FPCB, and the other surface thereof may be attached to the liquid crystal panel. 
         [0024]    The adhesive member may be formed on the top surface of the FPCB, and the liquid crystal display may further include a light blocking tape provided between the liquid crystal panel and the main support. 
         [0025]    The adhesive member may have a tape shape. 
         [0026]    Yet another exemplary embodiment provides a liquid crystal display including: a liquid crystal panel; a plurality of light emitting diodes (LEDs) configured to emit light; a flexible printed circuit board (FPCB) in which the LEDs are mounted; a light guide disposed to have a surface corresponding to light emitting surfaces of the LEDs; a main support configured to accommodate the LEDs and the light guide therein; a light blocking tape configured to fix a top surface of the FPCB and the liquid crystal panel; and an adhesive member formed to fix a bottom surface of the FPCB, the main support, and the light guide, wherein one surface of the adhesive member is attached to the FPCB, the other surface thereof is attached to the main support and the light guide, and the adhesive member is formed between the LEDs. 
         [0027]    Yet another exemplary embodiment provides a manufacturing method of a backlight assembly, including: disposing a plurality of light emitting diodes (LEDs) in a flexible printed circuit board (FPCB); disposing a mask on the FPCB, the mask having holes of predetermined shapes formed at a position at which an adhesive member is to be printed on the FPCB in which the LEDs are disposed; and coating the adhesive member on the mask. 
         [0028]    Yet another exemplary embodiment provides a manufacturing method of a backlight assembly, including: disposing a plurality of LEDs on an FPCB; printing an adhesive member at a position at which the adhesive member is to be printed on the FPCB in which the LEDs are disposed on a release liner; printing the adhesive member on the FPCB by covering the release liner on which the adhesive member is printed on the FPCB in which the LEDs are disposed; and removing the release liner. 
         [0029]    The manufacturing method may further include: forming a protective film on the release liner and the adhesive member; and removing the protective film after the printing of the adhesive member at the position at which the adhesive member is to be printed on the FPCB. 
         [0030]    In accordance with the exemplary embodiments, it is possible to provide a backlight assembly and a liquid crystal display including the same, which can reduce an undesired light leakage phenomenon by disposing an adhesive member between a plurality of LEDs located in an FPCB but not continuously along a light outputting pathway between a light emitting diode and a light guide in a backlight unit. 
         [0031]    It is also possible to adhere a panel and a light guide by using one adhesive member to thereby simplify a manufacturing process of a liquid crystal display. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]      FIG. 1  is an exploded perspective view showing a combination of a liquid crystal display assembly and backlighting assembly in accordance with an exemplary embodiment in accordance with the present disclosure of invention. 
           [0033]      FIG. 2  is a perspective view showing a flexible printed circuit board (FPCB) and a patterned, double-sided adhesive member used within the combination of  FIG. 1 . 
           [0034]      FIG. 3  is a cross-sectional view taken along a line I-I of  FIG. 1 . 
           [0035]      FIG. 4  is a perspective view showing a flexible printed circuit board (FPCB) and a patterned, double-sided adhesive member in accordance with another exemplary embodiment. 
           [0036]      FIG. 5  is a perspective view showing a coupled state of the flexible printed circuit board and the adhesive member in accordance with an exemplary embodiment. 
           [0037]      FIG. 6  is a cross-sectional view showing a liquid crystal display taken along a line I-I of  FIG. 1  in accordance with a further exemplary embodiment. 
           [0038]      FIG. 7  is a perspective view showing a coupled state of the flexible printed circuit board and the adhesive member in accordance with a first modification. 
           [0039]      FIG. 8  is a perspective view showing a coupled state of the flexible printed circuit board and the adhesive member in accordance with a second modification. 
           [0040]      FIG. 9  shows a manufacturing process for a backlight assembly in accordance with an exemplary embodiment. 
           [0041]      FIG. 10  shows another manufacturing process for a backlight assembly in accordance with another exemplary embodiment. 
           [0042]      FIG. 11  is a comparative photographic view showing a light leakage phenomenon of a liquid crystal display to which a backlight unit is applied in accordance with an exemplary embodiment of the present disclosure. 
           [0043]      FIG. 12  is a graph showing measured incident light efficiency of the liquid crystal display to which the backlight unit is applied in accordance with the present exemplary embodiment. 
           [0044]      FIG. 13  is a graph showing a measured color coordinate deviation of the liquid crystal display to which the backlight unit is applied in accordance with the present exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0045]    Hereinafter, exemplary embodiments in accordance with the present disclosure of invention will be described in detail with reference to the attached drawings such that the present teachings can be easily put into practice by those skilled in the art. As those skilled in the art would realize in light of this disclosure, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present teachings. 
         [0046]    In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like reference numerals designate like elements throughout the specification. When a first part of a layer, a film, a plate, or the like is described as being arranged “on” or “over” a second part, this indicates that the first part is arranged on or over the second part directly or with a third part therebetween without the limitation to the upper side thereof on the basis of the gravity direction. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. 
         [0047]    A backlight assembly and a liquid crystal display including the same will now be described with reference to the accompanying drawings in accordance with a first exemplary embodiment of the present disclosure. 
         [0048]    First, a backlight assembly and a liquid crystal display including the same will be described with reference to  FIG. 1  to  FIG. 3  in accordance with an exemplary embodiment. 
         [0049]      FIG. 1  is an exploded perspective view showing a liquid crystal display in accordance with the first exemplary embodiment.  FIG. 2  is a perspective view showing a flexible printed circuit board and an adhesive member.  FIG. 3  is a cross-sectional view showing a liquid crystal display taken along a line I-I of  FIG. 1 . 
         [0050]    Referring to  FIG. 1 , the liquid crystal display of the present exemplary embodiment includes a liquid crystal panel  110  on which an image is to be displayed, and a backlight assembly  130  disposed at a bottom portion of the liquid crystal panel  110  to supply light to the latter. 
         [0051]    A first flexible printed circuit board (FPCB)  115  to which a data signal and a control signal are applied from the outside is provided at an edge of the liquid crystal panel  110 . 
         [0052]    The first FPCB  115  may be a substrate formed of a heat-resistant plastic film such as a flexible material, e.g., polyester (PET) or polyimide (PI) as a circuit board in which complex circuits are formed on the flexible insulation film. The FPCB  115  has been frequently used for small liquid crystal display modules since it can take useful advantage of available space, for example by providing three-dimensional wiring thanks to its flexibility. 
         [0053]    In the liquid crystal panel  110 , a driving driver (e.g., integrated circuit)  113  is mounted at a region that is grounded with the first flexible printed circuit board  115 . The liquid crystal panel  110  receives an outside signal from the first flexible printed circuit board  115 , and the driving driver  113  generates a driving signal for driving the liquid crystal panel  110  by using the outside signal. 
         [0054]    The liquid crystal panel  110  includes a thin film transistor (TFT) substrate  111 , a color filter substrate  112  provided to face the thin film transistor substrate  111 , and a liquid crystal (not shown) interposed therebetween. 
         [0055]    One end of the thin film transistor substrate  111  is extended to be longer than that of the color filter substrate  112 . Accordingly, the chip-shaped driving driver  113  may be mounted at an end of the thin film transistor substrate  111 . 
         [0056]    The backlight assembly  130  disposed at the bottom surface of the liquid crystal panel  110  includes a light source unit  180  disposed at a side portion thereof, a light guide  150  disposed to have a light receiving surface aligned opposite to a light emitting surface of the light source unit  180 , where the light guide  150  (LGP) is configured to convert point sourced light into diffused surface light, optical sheets  140  disposed on the light guide to further diffuse and/or otherwise improve characteristics of the light emitted from the light guide  150 , and a reflective sheet  160  disposed at the bottom surface of the light guide  150  to reflect light emitted in a downward direction of the light guide  150  back toward the liquid crystal panel  110 . 
         [0057]    The backlight assembly  130  further includes a main support  170  formed of a quadrangular frame mold material and shaped to accommodate the light source unit  180 , the light guide  150 , the optical sheets  140 , and the reflective sheet  160  therein. 
         [0058]    A double-sided light blocking tape  120  is disposed on the main support  170  and is used to affix together the light source unit  180 , the light guide  150 , the optical sheets  140 , and the reflective sheet  160  so as to thereby prevent their breakaway from the main support  170 , and to further affix them relative to the liquid crystal panel  110 . 
         [0059]    The light blocking tape  120  has opposite surfaces coated with an adhesive to affix together the backlight assembly  130  and the liquid crystal panel  110 , and is entirely formed of a black colored or otherwise opaque material so as to prevent light emitted from the backlight assembly  130  from leaking to the outside. 
         [0060]    When the backlight assembly  130  and the liquid crystal panel  110  are assembled by using the light blocking tape  120  as part of the assembly process, the FPCB  115  may be bent 180 degrees to have a portion thereof disposed at a bottom surface of the main support  170 . 
         [0061]    The light guide  150  may be made of polymethylmethacrylate (PMMA). Further, although not shown, the light guide  150  may be formed to have a wedge shape with its thickness becoming thinner when moving away from an incident surface thereof on which the light source unit  180  is disposed and toward a more distant portion. 
         [0062]    A prism pattern may be formed on the bottom surface of the light guide  150  to reflect incident light toward the optical sheets  140 . 
         [0063]    The optical sheets  140  may include a diffuser sheet for diffusing light, a concentrating sheet for concentrating light, and a protecting sheet for protecting the diffuser sheet and the concentrating sheet from contaminants and/or scratching. 
         [0064]    The light source unit  180  includes a second FPCB  185  in which wiring is formed, and a plurality of LEDs  181  disposed at a predetermined distance from each other on a bottom surface of the second FPCB  185 . 
         [0065]    The second FPCB  185  is a substrate formed of a heat-resistant plastic film such as a flexible material, e.g., polyester (PET) or polyimide (PI) as a circuit board in which complex circuits are formed on the flexible insulation film. 
         [0066]    A double-sided and patterned adhesive member  200  is provided at the bottom surface of the second FPCB  185  to correspond to surface portions of the second FPCB  185  other than surface regions at which the LEDs  181  are mounted and other than surface regions through which light emitted from the LEDs  181  is to pass on its way to the LGP  150 . The surface regions at which the double-sided and patterned adhesive member  200  is present may be used to alignably affix the second FPCB  185  to the main support  170  and to the light guide  150  so that these initially separate components are held together. 
         [0067]    A problem that is present in a typical small liquid crystal display is that of light leakage through the affixing adhesive, especially where the adhesive is a light conducting one that is located between the light guide plate and the FPCB on which the LEDs are mounted. In such a case, light emitted from the LEDs can pass through the light conducting adhesive region, thereby creating the problem of light leakage coming out at locations of the adhesive region. 
         [0068]    In contrast to the above typically organization, the adhesive member  200  of the present exemplary embodiment is patterned to have leakage-reducing or minimizing grooves  203  formed at the surface regions at which the LEDs  181  are disposed and at the surface regions through which light directly emitted from the LEDs  181  passes so that such directly emitted light is not easily coupled into the layer of the adhesive member  200 . In other words, the adhesive member  200  is not formed so as to have a parasitic light entrance structure at surface regions at which the LEDs  181  are disposed and at surface regions through which the high intensity light emitted from the LEDs  181  directly passes on its way to the LPG  150 . On the other hand, for the sake of enhanced adhesion between the second FPCB  185  and the other components to which the second FPCB  185  is to be affixed to, the patterned adhesive member  200  does have portions formed and disposed in surface regions between where the LEDs and their high intensity light output paths are located along the bottom surface of the second FPCB  185 . 
         [0069]    The adhesive member  200  may be patterned to have sections each of a quadrangular shape between the LEDs  181 , but the shape of each of the interposed sections of the adhesive member  200  may instead include, and merely as an example, a triangle, a circle, and/or a trapezoid without being limited thereto. Specifically, the adhesive member  200  may be formed to have interposed sections between the LEDs  181  where the sections extend entirely in a vertically longitudinal direction on the bottom surface of the second FPCB  185 , as shown for example in  FIG. 2 . Alternatively the adhesive member  200  may be formed at regions on the top surface of the second FPCB  185  (see briefly  FIG. 6 ) as well as having spaced apart sections on the bottom surface of the second FPCB  185  but interposed between the LEDs  181 . 
         [0070]    One portion of the adhesive member  200  is brought into contact with an upper surface of a side portion of the main support  170 , and another portion of the adhesive member  200  is brought into contact with an upper surface portion at a side edge of the light guide plate (LGP)  150  such that the adhesive member  200  simultaneously bonds to the main support  170  and to the LGP  150  and thus affixes the second FPCB  185  to both of them. The double-sided adhesive member  200  has opposite surfaces coated with adhesive where one of the opposed surfaces thereof is brought into adhering contact with the second FPCB  185  and the other of the opposed surfaces thereof is brought into adhering contact with both the light guide  150  and the main support  170  so as to thereby affix the three components one to the next. 
         [0071]    A double-sided affixing tape and/or a curable fluid adhesive may be employed as the adhesive member  200 , but it is not limited thereto. 
         [0072]    Without being bound to any specific theory, it is believed that light leakage through the adhesive member is high when the adhesive member defines a continuous light conducting pathway composed continuously of the material of the adhesive member while light leakage is substantially reduced when one or more air-filled grooves such as 203 interrupt the coupling of leakage light particularly along the high-intensity light emitting pathways of the LEDs  181 . By keeping the light emitting pathways of the LEDs  181  substantially clear of a continuum of the material of the adhesive member  200 , light leakage is substantially reduced while the adhesive affixing function of the adhesive member is not substantially degraded. 
         [0073]    Hereinafter, a backlight assembly and a liquid crystal display including the same will be described in detail with reference to  FIG. 4  to  FIG. 6  in accordance with another exemplary embodiment in accordance with the present disclosure of invention. 
         [0074]      FIG. 4  is a perspective view showing a flexible printed circuit board  185  and a patterned adhesive member  200  in accordance with another exemplary embodiment.  FIG. 5  is a perspective view showing a coupled state of the flexible printed circuit board and the adhesive member in accordance with the present exemplary embodiment.  FIG. 6  is a cross-sectional view showing a liquid crystal display taken along a line I-I of  FIG. 1  in accordance with this exemplary embodiment when the end of the adhesive member  200  distal from the LEDs is folded over along the fold line of  FIG. 4  so as to define a U-shaped layer disposed about both the bottom and top surfaces of the second FPCB  185 . 
         [0075]    The backlight assembly and the liquid crystal display including the same shown in  FIG. 4  to  FIG. 6  is substantially the same as that shown in  FIG. 1  to  FIG. 3  except for the adhesive member  200  being disposed on both upper and lower surfaces of the second FPCB  185 , and thus no repeated description will be provided of the parts that remain the same. 
         [0076]    Referring to  FIG. 4  to  FIG. 6 , the light source unit  180  includes the second FPCB  185  in which printed wiring is formed, and on which the LEDs  181  are disposed at a predetermined distance from each other and along the bottom surface of the second FPCB  185 . 
         [0077]    The second FPCB  185  is a substrate formed of a heat-resistant plastic film such as a flexible material, e.g., polyester (PET) or polyimide (PI) as a circuit board in which complex circuits are formed on the flexible insulation film. 
         [0078]    As best seen in  FIG. 5 , spaced apart sections of the adhesive member  200  are provided on the bottom surface of the second FPCB  185  at surface portions other than the regions at which the LEDs  181  are disposed and other than the regions through which the high intensity light emitted directly from the LEDs  181  passes. These spaced apart sections of the adhesive member  200  help to affix the second FPCB  185  simultaneously to both the main support  170  and to the light guide  150  while at the same time not providing a path for high intensity leakage light to easily enter into the layer of the adhesive member  200 . 
         [0079]    More specifically, the adhesive member  200  of the present exemplary embodiment has a structure in which grooves  203  are formed at the regions at which the LEDs  181  are disposed and at the regions through which high intensity light emitted from the LEDs  181  passes where the not-present adhesive layer material of the grooves  203  does not provide an optical entrance mechanism for allowing significant portions of the high intensity light emitted from the LEDs  181  to enter into the layer of the adhesive member  200 . In other words, the adhesive member  200  is not formed at the regions at which the LEDs  181  are disposed and at the regions through which the light emitted from the LEDs  181  directly passes, but is formed and disposed between the LEDs located on the bottom surface of the second FPCB  185 . 
         [0080]    The spaced apart bottom sections of the adhesive member  200  may be formed each in a quadrangular shape between the adjacent LEDs  181 . Alternatively, the sections of the adhesive member  200  may be formed between the LEDs  181  entirely as strips extending in a vertical direction on the bottom surface of the second FPCB  185  and looping over to the top surface of the second FPCB  185 . 
         [0081]    Herein, the adhesive member  200  disposed between the LEDs  181  on the bottom surface of the second FPCB  185  has a structure to extend in such a way so as to entirely cover a side surface and a top surface of the second FPCB  185 . 
         [0082]    One portion of the adhesive member  200  is brought into contact with an upper surface of a side portion of the main support  170 , and another portion thereof is brought into contact with an upper surface at a side portion of the light guide  150 . Further, a portion of the adhesive member  200  which covers the top surface of the second FPCB  185  may be brought into cross-adhering contact with the light blocking tape  120  disposed at the upper portion of the second FPCB  185 . 
         [0083]    The adhesive member  200  has opposite surfaces coated with adhesive, so that the liquid crystal panel  110  may be directly affixed to the top surface of the second PCB  185  by way of the folded over adhesive member  200  along with the affixing of the separate components  170  and  150  of the backlight assembly  130  to the second PCB  185  and therethrough to each other. Typically, opposite surfaces of the light blocking tape  120  are coated with adhesive to fix together just a corresponding part of the backlight assembly  130  and the liquid crystal panel  110 . In contrast, in accordance with the present exemplary embodiment, the adhesive member  200  can be additionally disposed at the top surface of the second FPCB  185  to perform this function in combination with the light blocking tape  120 . 
         [0084]    Specifically, the adhesive member  200  has opposite surfaces coated with adhesive, so that one surface of the adhesive member  200  disposed on the bottom surface of the second FPCB  185  is brought into contact with the bottom surface of the second FPCB  185  and the other surface thereof is brought into contact with the light guide  150  and the main support  170 , and one surface of the adhesive member  200  disposed on the top surface of the second FPCB  185  is additionally brought into contact with the top surface of the second FPCB  185  and the other surface thereof is directly brought into contact with the light blocking tape  120  and/or the liquid crystal panel  110 . 
         [0085]    A double-sided affixing tape and/or a curable fluid adhesive may be employed in the adhesive member  200  used in the backlight assembly  130  of the immediately above described exemplary embodiment. 
         [0086]    Hereinafter, a combined backlight assembly and a liquid crystal display including the same but with slightly modified, inter-LED sections of the adhesive member  200  will be described in detail with reference to  FIG. 7  as being in accordance with yet another exemplary embodiment. 
         [0087]      FIG. 7  is a perspective view showing a coupled state of the flexible printed circuit board and the adhesive member in accordance with a first modification. 
         [0088]    The backlight assembly and the liquid crystal display including the same shown in  FIG. 7  is substantially the same as that shown in  FIG. 4  to  FIG. 6  except for the shape of the inter-LED sections of the adhesive member  200  that are disposed on the bottom surface of the second FPCB  185 , and thus no repeated description will be provided. 
         [0089]    As shown in  FIG. 7 , the adhesive member  200  may be disposed on the bottom surface of the second FPCB  185  in sections each of a trapezoidal shape instead of the quadrangular shape shown in  FIG. 4  to  FIG. 6  in which the adhesive member  200  is disposed. The grooves between the trapezoidally shaped inter-LED sections of the adhesive member  200  of  FIG. 7  allow the high intensity light emitted from the LEDs to fan out as it passes through the grooves toward the light incident edge of the LGP  150  (not shown). 
         [0090]    Hereinafter, a backlight assembly and a liquid crystal display including the same will be described in detail with reference to  FIG. 8  in accordance with yet another exemplary embodiment. 
         [0091]      FIG. 8  is a perspective view showing a coupled state of the flexible printed circuit board and the adhesive member in accordance with a second modification. 
         [0092]    The backlight assembly and the liquid crystal display including the same shown in  FIG. 8  is substantially the same as that shown in  FIG. 4  to  FIG. 6  except for the shape of the inter-LED sections of the adhesive member  200  disposed on the bottom surface of the second FPCB  185 , and thus no repeated description will be provided. 
         [0093]    As shown in  FIG. 8 , the patterned adhesive member  200  may be disposed on the bottom surface of the second FPCB  185  to have spaced apart inter-LED sections each of a triangular shape instead of the quadrangular shape shown in  FIG. 4  to  FIG. 6  in which the adhesive member  200  is disposed. The grooves between the triangularly shaped inter-LED sections of the adhesive member  200  of  FIG. 8  allow the high intensity light emitted from the LEDs to fan out even more as it passes through the grooves toward the light incident edge of the LGP  150  (not shown). The triangle shapes may be formed by cutting away one or more side parts of the trapezoids of  FIG. 7 . 
         [0094]    Hereinafter, a manufacturing method of a backlight assembly will be described in detail with reference to  FIG. 9  in accordance with an exemplary embodiment. 
         [0095]      FIG. 9  shows a manufacturing process of the backlight assembly in accordance with the present exemplary embodiment. 
         [0096]    Referring to  FIG. 9 , the FPCB  185  in which the LEDs  181  are disposed is disposed at the bottom, and a mask  300  having holes  301  formed at positions at which striped sections of the adhesive member  200  will be printed (e.g., as ink jet deposited adhesive fluid) are located above the second flexible printed circuit board  185 . 
         [0097]    Herein, the holes  301  formed in the mask  300  may be formed in a shape of a quadrangle, a triangle, a circle or the like according to a to-be-printed shape of the adhesive member  200 , and may be variously formed according to positions and shapes of the adhesive member  200 . 
         [0098]    Thereafter, the adhesive member  200  is printed onto the bottom surface of the second FPCB  185  through the holes  301  formed in the mask  300  by coating the material of the adhesive member  200  on a top surface of the mask  300 , thereby completing a backlight assembly in accordance with this exemplary embodiment. 
         [0099]    Hereinafter, a backlight assembly will be described in detail with reference to  FIG. 10  in accordance with an exemplary embodiment. 
         [0100]      FIG. 10  shows another manufacturing process of the backlight assembly in accordance with the present exemplary embodiment. 
         [0101]    Referring to  FIG. 10 , the adhesive member  200  is printed on a top surface of a release liner  305  to correspond to a position of the adhesive member  200  to be printed on the second FPCB  185 , and a top surface of the adhesive member  200  is covered with a protective film  310 . 
         [0102]    In this case, when the adhesive member  200  is directly printed on the FPCB  185 , the protective film  310  may not be attached thereon. 
         [0103]    Then, the protective film  310  is removed. Thereafter, the adhesive member  200  is printed on the FPCB  185  with its desired patterned shapes by covering the release liner  305  having the adhesive member  200  printed on the top surface thereof on the FPCB  185 , and then the release liner  305  is removed (e.g., by a thermal release process) to thereby complete the backlight assembly in accordance with the present exemplary embodiment. 
         [0104]    It was tested whether a light leakage phenomenon can be reduced by applying the backlight assembly of the present exemplary embodiment to a liquid crystal display in order to examine an effect of reducing light leakage when applying the backlight assembly  130  in which the adhesive member  200  is disposed to define grooves  203  where the LEDs  181  are disposed on the bottom surface of the second FPCB  185 . The test was performed by applying a backlight assembly in which the adhesive member  200  is disposed also along the light emitting pathways of the LEDs  181  to a first part of the liquid crystal display as a comparative example, and applying the backlight assembly of the present exemplary embodiment to a second part of the liquid crystal display. This result is shown in  FIG. 11 . 
         [0105]      FIG. 11  is a comparatively photographed view showing the light leakage phenomenon of a liquid crystal display to which a backlight unit is applied in accordance with the exemplary embodiment of the present disclosure of invention. 
         [0106]    As shown in  FIG. 11 , it is seen that the light leakage phenomenon is remarkably reduced on the right side of the photograph when outer appearances of the first part and the second part of the liquid crystal display are compared in the case that the adhesive member  200  is disposed between the LEDs  181  and the comparative example. 
         [0107]    Further, it was tested whether incident light efficiency can be improved by applying the backlight assembly of the present exemplary embodiment to a liquid crystal display in order to examine an effect of improving the incident light efficiency when applying the backlight assembly  130  in which the adhesive member  200  is disposed between the LEDs  181  disposed on the bottom surface of the second FPCB  185 . As a comparative example, an incident light efficiency of a liquid crystal display applied with a backlight unit in which the adhesive member  200  is also disposed along the light emitting pathways of the LEDs  181  was also measured. This result is shown by the plots of  FIG. 12 . 
         [0108]      FIG. 12  is a graph showing the measured incident light efficiency of the liquid crystal display to which the backlight unit is applied in accordance with the present exemplary embodiment. 
         [0109]    The horizontal axis of the graph shown in  FIG. 12  indicates each measurement point of the liquid crystal display, and the vertical axis indicates a light amount. 
         [0110]    As shown in  FIG. 12 , it is seen that the light amounts at most of the measurement points are increased by about 20% on average when the backlight assembly of the present exemplary embodiment is used as compared with the comparative example. Since there is less light leakage by keeping the light emitting pathways of the LEDs  181  substantially clear of the adhesive member  200 , the light output of the same embodiment is improved as is seen in  FIG. 12 . 
         [0111]    Furthermore, it was tested whether a color coordinate deviation can be reduced by applying the backlight assembly of the present exemplary embodiment to a liquid crystal display in order to examine an effect of reducing the color coordinate deviation when applying the backlight assembly  130  in which the adhesive member  200  is disposed between the LEDs  181  disposed on the bottom surface of the second FPCB  185 . As a comparative example, a color coordinate deviation of a liquid crystal display applied with a backlight unit in which the adhesive member  200  is disposed in a light emitting direction of the LEDs  181  was also measured. This result is shown in  FIG. 13 . 
         [0112]      FIG. 13  is a graph showing the measured color coordinate deviation of the liquid crystal display to which the backlight unit is applied in accordance with the present exemplary embodiment. 
         [0113]    The horizontal axis of the graph shown in  FIG. 13  indicates each measurement point of the liquid crystal display, and the vertical axis indicates a color coordinate deviation 
         [0114]    As shown in  FIG. 13 , it is seen that the color coordinate deviations at most of the measurement points on average are measured as small values of about 20% when the backlight assembly of the present exemplary embodiment is used as compared with the comparative example. Without being bound to any specific theory, it is believed that light leakage through the adhesive member is not uniform across all wavelengths of the visible spectrum. Since there is less light leakage by keeping the light emitting pathways of the LEDs  181  substantially clear of the adhesive member  200 , the light output of the same embodiment is more consistent across the wavelengths of the visible spectrum as is seen in  FIG. 13 . 
         [0115]    As described above, in accordance with the exemplary embodiments of the present disclosure, it is possible to provide a backlight assembly and a liquid crystal display including the same which can reduce a light leakage phenomenon by disposing an adhesive member between a plurality of LEDs located in an FPCB instead of between a light emitting diode and a light guide in a backlight unit, and can adhere a panel and a light guide by using one adhesive member to thereby simplify a manufacturing process of a liquid crystal display. 
         [0116]    While this disclosure of invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the teachings are not limited to the disclosed embodiments, but, on the contrary, the disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the present teachings.

Technology Category: 4