Abstract:
There is disclosed a light emitting diode module capable of being used as a line light source and a planar light source and a flat panel display using the same. The flat panel display includes a panel unit displaying images and a backlight assembly. The backlight assembly includes a light emitting diode module supplying a light to the panel unit and guides the light to the panel unit. The light emitting diode module includes a plurality of light emitting diodes that emits light and a package that encloses the light emitting diodes. The package has a light emitting surface providing a passage of the light from the light emitting diodes and has a plurality of gratings formed thereon.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application claims priority to Korean patent application No. 2004-0032181 filed in the Korean Intellectual Property Office on May 7, 2004, the entire contents of which are herein incorporated by reference in their entirety.  
       BACKGROUND OF THE INVENTION  
       [0002]     (a) Field of the Invention  
         [0003]     The present invention relates to a light emitting diode module (LED module) and a flat panel display provided with the same, and more particularly, to an LED module capable of being used as a line light source and a planar light source, and a flat panel display provided with the same.  
         [0004]     (b) Description of the Related Art  
         [0005]     Recently, with the rapid development of semiconductor technology, the demand for a small-size and lightweight flat panel display but having a better performance has increased.  
         [0006]     Among the flat panel displays, a liquid crystal display (LCD) has the merits of small size, light and lower power consumption. Therefore, much attention has been paid to the LCD as an alternative to the existing cathode ray tube. Nowadays, LCD is widely used for almost all information processing apparatuses requiring display devices.  
         [0007]     In a typical LCD, a specific molecular alignment is changed into another molecular alignment by applying a voltage, and a change of optical characteristics of a liquid crystal cell such as birefringence, optical rotary power, dichroism, and optical scattering are converted into a visual change. Thus, information is displayed using an optical modulation of the liquid crystal cells in the LCD.  
         [0008]     Since an LCD is a passive device which cannot emit light for itself, the backlight unit is indispensable to the LCD to supply a light source. In the case of a medium or large-sized LCD such as a monitor and a TV, a lamp is used as a backlight. The lamp has not only large power consumption but also has undesired influence on the characteristics of the LCD panel caused by the discharge of heat. Also, since a lamp is conventionally a stick type, there is a problem in that the lamp is not only easily affected by impact but also the display quality comes to be poor due to large temperature deviation of each part.  
         [0009]     On the other hand, a light emitting diode (LED) is used as a backlight in a small-size LCD in mobile products such as a cellular phone. Since the LED is a semiconductor device, there are advantages of longer durability, faster lighting, lower power consumption, high shock resistance, and suitability to miniaturization. Thus, when an LED having these advantages is applied to a medium or large-sized LCD, the above-described problems can be solved. That is, by changing the LED of a point light source into a line light source or a planar light source, the LED could have been gradually applied in medium-sized LCD products or large-sized LCD products.  
         [0010]     However, since the LED has a limit of light emitting angle due to the unique characteristics thereof, there is a weak point that a light is not transferred from the LED to all directions. Specifically, in the case of LCD products using three kinds of LEDs such as red (R), green (G), and blue (B), there is a problem in that the loss of light increases due to light reflection and dark spots are formed between LEDs due to the limit of light emitting angle.  
       SUMMARY OF THE INVENTION  
       [0011]     The present invention is contrived to solve the above problems and the present invention provides an LED module, which can be simply used as a line light source or a planar light source and has minimized loss of light, and a flat panel display provided with the same.  
         [0012]     According to the present invention, a flat panel display includes a panel unit displaying one or more images, and a backlight assembly including an LED module supplying a light to the panel unit and guiding the light to the panel unit. The LED module includes a plurality of light emitting diodes that emits light and a package that encloses the LEDs. The package has a light emitting surface providing a passage of the light from the LEDs and has a plurality of gratings formed thereon.  
         [0013]     Preferably, the flat panel display further comprises a reflecting layer formed on at least one of the surfaces of the package adjacent to the light emitting surface of the package.  
         [0014]     More preferably, the flat panel display further comprises a reflecting layer formed on a surface of the package facing the light emitting surface of the package.  
         [0015]     Preferably, the flat panel display further comprises a diffusion layer formed on inner or outer surface of the light emitting surface of the package.  
         [0016]     More preferably, the flat panel display comprises an index matching member and a light guiding plate (LGP). The index matching member is coated on an outer surface of the light emitting surface of the package. The light guiding plate is disposed adjacent to the index matching member.  
         [0017]     Preferably, a refractive index n 3  of the index matching member satisfies a relation of (n 1 +n 2 )/2&lt;n 3 ≦n 2 . Here, n 1  is a refractive index of air and n 2  is a refractive index of the LGP.  
         [0018]     The refractive index of the index matching member is preferably in the range of about 1.4 to about 1.5.  
         [0019]     The plurality of LEDs can be arrayed in a line.  
         [0020]     The plurality of LEDs can be arrayed in a matrix.  
         [0021]     Preferably, the backlight assembly further includes a diffusing plate disposed over the LED module.  
         [0022]     The panel unit can be a liquid crystal panel unit.  
         [0023]     The present invention provides the LED module including a plurality of LEDs that emits light and a package that encloses the LEDs. The package has a light emitting surface providing a passage of the light from the LEDs and has a plurality of gratings formed thereon.  
         [0024]     Preferably, the LED module further comprises a reflecting layer formed on at least one of surfaces of the package adjacent to the light emitting surface of the package.  
         [0025]     More preferably, the LED module further comprises a reflecting layer formed on a surface of the package facing the light emitting surface of the package.  
         [0026]     Preferably, the LED module further comprises a diffusion layer formed on inner or outer surface of the light emitting surface of the package.  
         [0027]     The plurality of LEDs can be arrayed in a line in the LED module according to the present invention.  
         [0028]     The plurality of LEDs can be arrayed in a matrix in the LED module according to the present invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]     The above and other features of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:  
         [0030]      FIG. 1  is an exploded perspective view of a flat panel display provided with an LED module according to a first embodiment of the present invention;  
         [0031]      FIG. 2  is a schematic diagram of an LED module according to the first embodiment of the present invention;  
         [0032]      FIG. 3  is a rear perspective view of a part of a flat panel display provided with an LED module according to a second embodiment of the present invention;  
         [0033]      FIG. 4  is an exploded perspective view of a flat panel display provided with an LED module according to a third embodiment of the present invention.  
         [0034]      FIG. 5  is a perspective view of an assembled flat panel display provided with an LED module according to the third embodiment of the present invention.  
         [0035]      FIG. 6  is a cross-sectional view taken along line AA of  FIG. 5 ;  
         [0036]      FIG. 7  is an exploded perspective view of a flat panel display provided with an LED module according to a fourth embodiment of the present invention;  
         [0037]      FIG. 8  is a perspective view of an assembled flat panel display provided with an LED module according to the fourth embodiment of the present invention;  
         [0038]      FIG. 9  is a schematic diagram of an LED module according to the fourth embodiment of the present invention;  
         [0039]      FIG. 10  is a cross-sectional view taken along line BB of  FIG. 8 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0040]     Hereinafter, exemplary embodiments of the present invention will be described with reference to the FIGS.  1  to  10 . These embodiments of the present invention are merely exemplary embodiments of the present invention, and thus are not limited thereto.  
         [0041]      FIG. 1  shows a flat panel display  100  provided with a LED module  10 , which is used in a mobile product such as a cellular phone and so on.  
         [0042]     The structure of the flat panel display  100  shown in  FIG. 1  is merely an exemplary structure of the flat panel display of the present invention and the present invention is not limited to the structure of the flat panel display shown in  FIG. 1 . Therefore, it is possible to modify the structure of the flat panel display in other forms.  
         [0043]     Although the panel unit  65  is shown as an LCD panel in  FIG. 1 , it is merely an example of a panel unit and the present invention is not limited to the LCD panel. Therefore, it is possible to use other panel unit instead of the LCD panel.  
         [0044]     The panel assembly  68  includes a panel unit  65 , an integrated circuit (IC) chip  67 , and a flexible printed circuit (FPC) board  69 .  
         [0045]     The panel unit  65  displays image thereon and includes two panels  61  and  63 . However, the panel unit  65  may include only one panel. An LCD, a representative of a non-emissive display device, usually includes two panels.  
         [0046]     Hereinafter, the flat panel display  100  in embodiments of the present invention will be described as an LCD. However, the present invention is applicable to any kind of display device that requires light source.  
         [0047]     The panel unit  65  includes a TFT (thin film transistor) array panel  63  including a plurality of TFTs, a color filter panel  61  disposed opposite the TFT array panel  63 , and a liquid crystal layer (not shown) disposed between the two panels  61  and  63 . The IC chip  67  is mounted on the TFT array panel  63 , thereby controlling the panel unit  65 .  
         [0048]     The TFT array panel  63  includes a transparent glass substrate and a plurality of pixel electrodes (not shown), a plurality of TFTs (not shown), and a plurality of signal lines (not shown) formed on the substrate. The pixel electrodes are arranged in a matrix and made of transparent conductor such as indium tin oxide (ITO) and indium zinc oxide (IZO) or reflective metal such as Al and Ag. The signal lines includes gate lines (not shown) and data lines (not shown) and each TFT has a gate connected to one of the gate lines, a source connected to one of the data lines, and a drain connected to one of the pixel electrodes.  
         [0049]     The data lines and the gate lines of the panel unit  65  are connected to the IC chip  67  and receive data signals and gate signals from the IC chip  67 , respectively. The TFTs turn on or turn off in response to the gate signals from the gate lines to selectively transmit the data signals to the pixel electrodes.  
         [0050]     On the other hand, the color filter panel  61  includes a plurality of color filters (not shown) facing the pixel electrodes and a common electrode (not shown) preferably made of transparent conductor such as ITO or IZO that covers the entire surface of the color filter panel  61 . The common electrode is supplied with a common voltage and the voltage difference between the pixel electrode and the common electrode generate an electric field in the liquid crystal layer. The electric field determines orientations of liquid crystal molecules in the liquid crystal layer and thereby determines the transmittance of light passing through the liquid crystal layer. The FPC  69  transmits a plurality of control signals for controlling the IC chip  67 .  
         [0051]     The backlight assembly  20  is disposed under the LCD panel assembly  68  in order to uniformly provide a light to the LCD panel  65 . The backlight assembly  20  is received in a bottom chassis  28 .  
         [0052]     The backlight assembly  20  includes an LED module  10  for providing light to the LCD panel  65 , a circuit board  18  for supplying power to the LED module  10 , an LGP  25  for guiding light emitted from the LED module  10  toward the LCD panel  65 , a reflecting sheet  26  for reflecting the light passed through the LGP  25 , and optical sheets  24  improving luminance of the light passed through the LGP  25  and supplying the light to the LCD panel  65 .  
         [0053]     A printed circuit board (not shown in  FIG. 1 ) (hereinafter referred to as a “PCB”) is disposed at the back of the bottom chassis  28  and is electrically connected to the FPC board  69  for transmitting a driving signal to the LCD panel  65 . In addition, the PCB is electrically connected to the circuit board  18  for supplying a power to drive the LED module  10 .  
         [0054]     The top chassis  60  is disposed over the panel assembly  68  to cover it. The top chassis  60  is not only assembled with the bottom chassis  28  but also bend the FPC  69  toward the outside of the mold frame  22 . The panel assembly  68  is fixed between the top chassis  60  and the bottom chassis  28 .  
         [0055]     As shown in  FIG. 1 , the flat panel display  100  according to the first embodiment of the present invention includes the LED module  10  including a plurality of LEDs and a package enclosing them. In addition, the LED module  10  can include other elements if necessary. The LED module  10  will be further explained in detail with reference to  FIG. 2 .  
         [0056]      FIG. 2  shows an LED module  10  according to the first embodiment of the present invention, which shows the LED module  10  shown in  FIG. 1  rotated by an 180 degrees with respect to X-axis.  
         [0057]     The LED module  10  includes a plurality of LEDs  12  and a package  11  enclosing them. There exist a plurality of gratings on the light emitting surface  13  of the package  11 , thereby minimizing total reflection of light emitted from the LEDs  12 . Furthermore, reflecting layers  16  (shown as hatched lines) are formed on at least one of surfaces of the package  11  which is adjacent to the light emitting surface  13  of it, thereby reflecting a light propagating toward an innerside of the LED  12  to the light emitting surface  13  of the package  11  and emitting the light therethrough. The reflecting layer  16  is also formed on a surface of the package  11  facing light emitting surface  13  of the package  11 , thereby reflecting the light and emitting it toward the light emitting surface  13  of the package  11 .  
         [0058]     Considering that the flat panel display is used in a small-sized mobile product such as a cellular phone and so on, white light with desirable brightness can be obtained by only using a group of a red LED, a blue LED and a green LED. Although LEDs  12  are arranged in order of R(red), B(blue) and G(green) in the LED module  10 , this is merely an example of the present invention and the present invention is not limited thereto. Therefore, LEDs can be arranged in another various methods. Furthermore, instead of using LEDs of three kinds of color, a blue LED and a yellow phosphor may be used together to form white light.  
         [0059]      FIG. 3  shows another flat panel display provided with an LED module  30  according to the second embodiment of the present invention.  FIG. 3  shows a flat panel display  300  omitting a reflecting sheet and a bottom chassis for convenience in order to show a modified LED module  30  covering with an index matching member  31 .  
         [0060]     The LED module  30  according to the second embodiment of the present invention is the same as the LED module according to a first embodiment of the present invention except the index matching member  31 . In addition, the structure of a flat panel display  300  is the same as that of the flat panel display shown in  FIG. 1  except the LED module  30 . Therefore, the same element is referred to as same reference number and detailed explanation thereof is omitted for convenience.  
         [0061]     As shown in  FIG. 3 , the LED module  30  covering with the index matching member  31  is adjacent to the LGP  25 . Since the LED module  30  is adjacent to the LGP  25 , the index matching member  31  minimizes loss of light therebetween.  
         [0062]     For example, if a gap is formed between the LED module  30  and the LGP  25 , loss of light occurs due to an air existing therebetween, which is caused by the difference between refractive indexes of the air and the LGP  25 . The refractive index n 1  of the air is 0, and the refractive index n 2  of the LGP made of PMMA(polymethyl methacrylate) is about 1.5. Therefore, it is preferable to insert an index matching member between an LED module and the LGP. The index matching member has a refractive index which is between that of the air and LGP, thereby minimizing the difference between the refractive indexes of the air and LGP. Furthermore, it is more preferable to insert an index matching member having a refractive index which is more similar to that of the LGP considering the fact that an index matching member is inserted between the LED module and the LGP.  
         [0063]     Taking these points into the consideration, it is desirable to choose an index matching member whose refractive index n 3  is over an average of the refractive index n 1  of the air and the refractive index n 2  of the LGP and is under the refractive index n 2  of the LGP. For example, glycerin can be chosen as an index matching member since its refractive index n 3  is about 1.46. The LED module  30  can be manufactured by applying a glycerin to the LED module  10  and hardening it by ultraviolet ray.  
         [0064]     The relationship among the refractive index n 3  of the index matching member, the refractive index n 1  of the air, and the refractive index n 2  of the LGP may be described as the following Relation 1. 
 
( n   1   +n   2 )/2 &lt;n   3   ≦n   2   [Relation 1]
 
         [0065]     More specifically, it is desirable that the refractive index n 3  of the index matching member  31  is set to be in the range from about 1.4 to about 1.5. If the refractive index n 3  is less than 1.4, there is a problem in that light is increasingly lost in proportion to an increasing reflectivity. On the contrary, since a general refractive index of the LGP is about 1.5, it is desirable that the refractive index n 3  of the index matching member does not exceed 1.5.  
         [0066]     The loss of light is minimized by using an index matching member satisfying the conditions described above. Namely, the light emitted from the LED module  30  passes through the LGP  25  without the loss of light.  
         [0067]      FIG. 4  is an exploded perspective view of a flat panel display  400  provided with an LED module  40  according to a third embodiment of the present invention.  FIG. 4  shows the LED module  40  which is a kind of a line light source.  
         [0068]     The LED module  40  can be applied to a middle-sized flat panel display such as a notebook computer and the elements included in the flat panel display  400  is similar to those included in the flat panel display shown in  FIG. 1 . Therefore, the same element is referred to as the same reference number and detailed explanation thereof is omitted for convenience. Accordingly, the different components of the flat panel display are mainly explained below.  
         [0069]     The structure of the flat panel display shown in  FIG. 4  is merely an exemplary structure of the flat panel display according to the present invention and the present invention is not limited thereto. Therefore, it is possible to modify the structure of the flat panel display in other forms.  
         [0070]     As shown in  FIG. 4 , a flat panel display  400  includes a backlight assembly  20  for supplying light to an LCD panel  65  on which image is displayed. The backlight assembly  20  supplies and guides light to the LCD panel  65 , and an LCD panel assembly  80  controls the LCD panel  65  in order to display image.  
         [0071]     Although the LCD panel  65  is shown as a panel unit in  FIG. 4 , it is merely an example of a panel unit and the present invention is not limited thereto. Therefore, it is possible to use other panel units.  
         [0072]     A plurality of driving integrated circuit packages  83 ,  81  are electrically connected to data lines and gate lines formed in the LCD panel  65 , respectively. The driving integrated circuit package can be chip on film (COF), tape carrier package (TCP) and so on.  
         [0073]     A plurality of data driving integrated circuit packages  83  are also electrically connected to the PCB  84  and transmits driving signals to the data lines formed in the LCD panel  65 . In addition, a plurality of data driving integrated circuit packages  83  transmit driving signals to a plurality of gate driving integrated circuit package  81  through the LCD panel  65 . Therefore, image can be displayed on the LCD panel  65 .  
         [0074]     The backlight assembly  20  includes an upper mold frame  22 , lower mold frame  89  and a bottom chassis  28  to fix inner elements of a backlight assembly  20 . The LED module  40  is received in the upper mold frame  22  and supplies light to the LGP  25 . The LED module  40 , optical sheets  24 , the LGP  25  and a reflecting sheet  26  are received in the bottom chassis  28 . The bottom chassis  28  is fixed in the lower mold frame  89 .  
         [0075]     Although not shown in  FIG. 4 , an inverter and a control board are disposed at the back of the bottom chassis  28 . The inverter transforms the exterior power into a uniform level and then provides it with the LED module  40  through the circuit board  18 . The control board converts analog data signal into digital data signal and transmits it to the LCD panel  65 .  
         [0076]      FIG. 5  shows a perspective view of a flat panel display  400  provided with an LED module  40 , which assembles all the parts of the flat panel display  400  shown in  FIG. 4 . The LED module  40  extends along an X-axis direction.  
         [0077]     As shown in an enlarged circle of  FIG. 5 , a plurality of LEDs  41  is arrayed in a package  42  along an X-axis direction. In  FIG. 5 , although the LEDs  41  are shown as an array in order of R, B, G, such diagram is merely an exemplary embodiment and the present invention is not limit thereto. Thus, it is possible to arrange the LEDs  41  in other forms. Since the electric connection between the LEDs  41  and its circuit board has been widely known to the skilled art in a technical field of the present invention, the detail explanation thereof is omitted.  
         [0078]      FIG. 6  shows a path of light which is emitted from the LED module  40  using an arrow. A reflecting layer  43  is partly formed on the inner surface of the package, thereby maximizing the amount of emitted light by reflecting light emitted from the LEDs  41 . Therefore, it is possible to improve brightness as much as possible. A plurality of gratings  47  are formed on the light emitting surface of the LED module  40  for improving brightness more effectively. The light emitting surface provides a passage of the light from the LEDs  41 .  
         [0079]     A diffusion layer  45  is formed at the outer surface of the light emitting surface of the package, thereby effectively scattering the light emitted from the LEDs  41 . Since the diffusion layer  45  is formed between the LEDs  41  and the LGP  25 , more uniformly diffused light can be forwarded into the LGP  25  from the LEDs  41 . On the contrary, the diffusion layer can be formed at the outer surface of the light emitting surface of the package.  
         [0080]      FIG. 7  shows a flat panel display  700  which is provided with an LED module  70  which is a kind of a planar light source. The LED module  70  according to a fourth embodiment of the present invention show in  FIG. 7  can be applied to a large-sized flat panel display such as a LCD TV and so on.  
         [0081]     In  FIG. 7 , since the basic structure of the flat panel display  700  is similar to that of the flat panel display shown in  FIG. 4 , the same elements are referred to as the same reference numbers and detailed explanations thereof are omitted.  
         [0082]     The structure of the flat panel display shown in  FIG. 7  is merely an exemplary structure of the flat panel display of the present invention and the present invention is not limited thereto. Therefore, it is possible to modify the structure of the flat panel display in other forms.  
         [0083]     In addition, although the LCD panel  65  is shown as a panel unit in  FIG. 7 , it is merely an example of a panel unit and the present invention is not limited thereto. Therefore, it is possible to use other panel units.  
         [0084]     As shown in  FIG. 7 , a flat panel display  700  includes an LCD panel  65  on which image is displayed and a backlight assembly  20  for supplying the light to the LCD panel  65 . An LCD panel assembly  80  includes an LCD panel  65 , driving integrated circuit package  81 ,  83 , and PCBs  82 ,  84 . A plurality of driving integrated circuit packages  81 ,  83  are electrically connected to gate lines and data lines formed on the LCD panel  65 , respectively. The driving integrated circuit package can be chip on film, tape carrier package and so on.  
         [0085]     The gate PCB  82  transmits gate driving signals to the LCD panel  65  through the gate driving integrated circuit packages  81  and the data PCB  84  transmits a data driving signals to the LCD panel  65  through the data driving integrated circuit packages  83 .  
         [0086]     A backlight assembly  20  is disposed below the LCD panel assembly  80  in order to provide the light to the LCD panel  65  on which image is displayed. Since the size of the LCD panel  65  is large, planar light source is indispensable to be provided in order to supply sufficient light to improve brightness. For improving brightness, a backlight assembly  20  also includes optical sheets  24 , a diffusing plate  79  and a reflecting sheet  26 . The light emitted from the LED module  70  is uniformly diffused when it is passed through the diffusing plate  79 . In addition, the LED module  70  can get an improved brightness due to the optical sheets  24 . The optical sheets  24 , the diffusing plate  79 , the LED module  70  and the reflecting sheet  26  are received in the bottom chassis  28  and are covered with the mold frame  22 . Then, the backlight assembly  20  is fixed by the mold frame  22  and the bottom chassis  28 .  
         [0087]      FIG. 8  shows an assembled flat panel display  700  provided with an LED module which is a kind of a planar light source.  
         [0088]     With the use of the LED module, it is possible to display image with high brightness on the LCD panel  65 . In addition, since a single compacted LED module is used as a light source, it is possible to simplify manufacturing process and decrease the number of the components to be assembled.  
         [0089]      FIG. 9  shows a schematic diagram of an LED module  70  as a planar light source which is included in a flat panel display shown in  FIG. 8 .  
         [0090]     As shown in  FIG. 9 , LED module  70  includes a plurality of LEDs  72  arrayed in a matrix. A plurality of LEDs  72  are enclosed in a package  75 . The arranging pattern of the LEDs  72  shown in  FIG. 9  is merely an example of the present invention and the present invention is not limited thereto. Thus, it is possible to arrange LEDs in various patterns.  
         [0091]     The reflecting layers  78  (shown as hatched lines) are formed on at least one of surfaces adjacent to a light emitting surface  76  of the LED module  70 , thereby reflecting the light emitted from the LEDs  72  and forwarding it to the light emitting surface  76 . Therefore, loss of light is noticeably decreased.  
         [0092]     In addition, since a plurality of gratings is formed on the light emitting surface  76  of the LED module  70 , light can be effectively concentrated. Namely, due to a plurality of gratings, the light trapped in the LED module  70  caused by total reflection can be minimized. The diffusion layer  74  is formed on the outer surface of the light emitting surface  76 , thereby regularly diffusing light. Although the diffusion layer  74  is formed on the LED module  70  as shown in  FIG. 9 , this is merely an example of the LED module of the present invention and the present invention is not limited thereto. Therefore, it is possible to exclude the diffusion layer  74  from the LED module  70  in some cases.  
         [0093]      FIG. 10  shows a path of light emitted from the LED module  70  using an arrow.  
         [0094]     As shown in  FIG. 10  using arrows, the light emitted from the LEDs  72  is reflected by a reflecting layer  78  and forwarded to the diffusing plate  79 . Since a diffusion layer  74  is coated at the outer surface of the light emitting surface  76 , it is possible to mix the various colors of light at first. Next, the light is uniformly diffused in passing through the diffusing plate  79  enough not to represent a bright line on the LCD panel  65 .  
         [0095]     As described above, according to the present invention, there is an advantage in that the LED module can be manufactured as a line light source and a planar light source as well. Therefore, the LED module can be applied to the apparatus using middle-sized LCD or large-sized LCD. In addition, since the LED module is manufactured in a single form, thereby simplifying manufacturing process to assemble it and decreasing the number of the components to be assembled.  
         [0096]     Since a plurality of gratings are formed on the light emitting surface of the package, the light trapped in the LED module caused by total reflection can be minimized.  
         [0097]     Furthermore, a reflecting layer is formed on at least one of surfaces of the package adjacent to the light emitting surface of the package, thereby reflecting the light trapped in the LED module to the light emitting surface of the package and improving brightness.  
         [0098]     Specifically, if a reflecting layer is formed on the surface of the package facing the light emitting surface, brightness can be more improved.  
         [0099]     Since an inner surface or an outer surface of the light emitting surface of the package is covered with a diffusion layer, the colors of the light can be mixed effectively by diffusing light emitted from LEDs.  
         [0100]     Specifically, the index matching member covering the LED module is adjacent to the LGP, thereby minimizing light reflection occurring between the LED module and the LGP.  
         [0101]     Since the index n 3  of the index matching member is not less than an average of the index n 1  of the air and the index n 2  of the LGP and not more than the index n 2  of the LGP, it is possible to minimize loss of light when the light is forwarded into the LGP.  
         [0102]     Further, the refractive index of the index matching member is set to be in the range from about 1.4 to about 1.5, thereby minimizing light reflection into the LED module.  
         [0103]     The plurality of the LEDs is arrayed in a line, thereby being used in the middle-sized LCD such as a monitor and so on. Accordingly, the number of components of an LCD can be remarkably reduced and thus assembling process can be simplified.  
         [0104]     In addition, the plurality of the LEDs is arrayed in a matrix, thereby being in the large-sized LCD such as a TV and so on.  
         [0105]     Especially, the generation of bright lines is prevented using a diffusing plate disposed over the LED module.  
         [0106]     Since a liquid panel unit is used as a panel unit, it is possible to directly apply the present invention.  
         [0107]     Although embodiments of the present invention have been described, it is understood that various changes and modifications can be made by one skilled in the art within the spirit and scope of the present invention as hereinafter claimed.