Abstract:
Disclosed are a light guiding plate having a slimmed thickness and small volume, a manufacturing method of the light guiding plate and a liquid crystal display (LCD) having the light guiding plate. The light guiding plate has a light reflection face with at least one brightness enhancement recess, which allows a light having an optical distribution of a planar light source to be supplied toward the LCD panel. A brightness concentration recess is formed in the light output face to concentrate the brightness. The brightness enhancement recess and the brightness concentration recess allow an enhancement in the brightness and an increase in the uniformity in the brightness. The light guiding plate excludes use of the diffusion sheet, the prism sheet and the reflection plate from a backlight assembly, thereby significantly decreasing the total weight and volume of the LCD.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a divisional of, and claims priority from, U.S. application Ser. No. 10/191,415, filed on Jul. 10, 2002, entitled “Light Guiding Plate, Method of Manufacturing the Same and Liquid Crystal Display Having the Light Guiding Plate,” and claims priority of Korean Patent Application No. 2001-42462 filed Jul. 13, 2001, both of which are incorporated by reference herein in their entireties. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to a light guiding plate, a method of manufacturing the same and a liquid crystal display (LCD) having the light guiding plate, and more particularly, to a light guiding plate having a slimmed thickness and small volume, in which a structure of a light supplying unit for supplying a light having an optical distribution of a planar light source into a LCD panel is improved to accomplish an enhancement in brightness, a low power consumption, an enhancement in optical uniformity and minimization in light loss. Further, the invention relates to a method of manufacturing the light guiding plate and a liquid crystal display having the light guiding plate.  
       DESCRIPTION OF THE RELATED ART  
       [0003]     Generally, an LCD is defined as a flat panel display that allows a user to recognize data processed in an information processing unit as characters, images and moving pictures using an optical property of liquid crystal in which light transmittance is varied depending on intensity of an applied electric field.  
         [0004]     Compared with a traditional cathode ray tube (CRT), LCDs offer various advantages such as lighter weight and smaller volume, even though the LCDs have the same resolution and screen size as the CRT.  
         [0005]     Such an LCD includes two sheets of very thin glass substrates facing each other and a liquid crystal layer interposed between the two glass substrates. In order to provide an electric field having a variable intensity in a small area unit, there is formed a plate shaped electrode on an inner surface of one glass substrate while there are formed plural electrodes each having an area corresponding to a desired resolution on an inner surface of the other glass substrate. After that, the two substrates are assembled with a space therebetween and liquid crystal is injected into the space in which light transmittance in the liquid crystal is varied depending on the intensity of an electric field which is applied to the liquid crystal.  
         [0006]     The liquid crystal layer functioning to control the light transmittance does not generate the light directly. This means that the light should be supplied toward the liquid crystal for performing the displaying operation. The light can be supplied from a natural light source or an artificial light source as a whole. In case of an artificial light source, the light is generated by consuming electric energy.  
         [0007]     The LCD using a natural light source has a fatal defect in that it is impossible to perform the displaying operation in a place where there is no natural light. Therefore, LCDs using an artificial light have been actively developed and spread.  
         [0008]     However, there are several problems in order to obtain a high quality image using an artificial light source. As an example, it is difficult to obtain a planar light source having an optical uniformity, i.e., a uniform brightness throughout the entire display area of the LCD.  
         [0009]      FIG. 1  is a simplified cross-sectional view of an LCD panel provided with a CUT (Cold cathode fluorescent tube) lamp having an optical distribution of linear light source and it shows that the linear light generated from the CUT lamp  1  is converted into a planar light having an optical distribution of a planar light source.  
         [0010]     Such a conversion from the linear light to the planar light is achieved by a light guiding plate  3 .  
         [0011]     The light guiding plate  3  is manufactured by using a synthetic resin-based material, and the light guiding plate  3  has a plate shape in a uniform thickness or a wedge shape whose thickness increases as it travels from one end to the other end.  
         [0012]     Such a structure renders the light having an optical distribution of a linear light source and having been generated from a lamp  1  to be incident from a sidewall  3   a  of to the light guiding plate  3 . The inputted light is reflected at an inner bottom surface  3   b  of the light guiding plate  3  and then outputted toward a direction of “A” through an upper surface  3   c  of the light guiding plate  3 .  
         [0013]     The light guiding plate  3  is appropriate for the planar light source but it is inappropriate for the light efficiency. In other words, the light guiding plate  3  has a disadvantage in that the light efficiency is lowered due to a light leakage.  
         [0014]     In order to enhance the light efficiency of the light guiding plate  3 , there are formed a plurality of reflection dots  3   d  in an outer bottom surface of the light guiding plate  3  by a silk screen method. However, these reflection dots  3   d  cause other problems.  
         [0015]     As one problem, for example, when the light guiding plate  3  having the reflection dots  3   d  is used for a long time, an original color of the reflection dots  3   d  is changed. The color-changed reflection dots  3   d  generates a yellowing phenomenon in which when an incident light is reflected by the reflection dots  3   d , the color of the reflected light is changed into a golden yellow. The yellowing phenomenon makes it difficult to display a desired color image.  
         [0016]     As another problem, it is difficult to form the dots  3   d  having a size of 100 pm or less by using the silk screen method.  
         [0017]     As still another problem, when forming the reflection dots  3   d , a failure in a desired shape occurs frequently.  
         [0018]     As further still another problem, when the light guiding plate is used for obtaining the planar light source, an optical distribution in the configuration of the planar light source can be obtained but the brightness distribution becomes non-uniform as indicated by reference number  5  in  FIG. 4 .  
         [0019]     Thus, in order to overcome the low display performance occurring when the light guiding plate  3  is used, a diffusion plate  6  is provided on the light guiding plate  3  as shown in  FIG. 2 . Reference symbol “B” in  FIG. 2  indicates a leakage light that is leaked through a side portion of the light guiding plate  3 . The diffusion plate  6  serves to diffuse the incident light that is incident from the light guiding plate  3  such that the light irradiated from the light guiding plate  3  has an optical distribution indicated by a reference numeral  7  of  FIG. 4 . Further, the diffusion plate  6  functions to prevent the reflection dots  3   d  of the light guiding plate  3  from being visualized.  
         [0020]     Thus, in the case that the diffusion plate  6  is used, the light irradiated from the light guiding plate  3  is scattered and thus a deficiency in the optical uniformity is somewhat overcome. However, the directionality of the light is lost during the light scattering. Therefore, after the light is incident into an LCD panel assembly  8 , the amount of the light decreases or the visual angle is lowered.  
         [0021]     In order to overcome this problem, as shown in  FIG. 3 , at least one prism sheet  9  is provided on the diffusion plate  6 . The prism sheet  9  changes an optical distribution of the light diffused through the diffusion plate  6  into an optical distribution indicated by a reference numeral  10  in  FIG. 4 .  
         [0022]     In the meantime, a part of the light that is incident into the light guiding plate  3  is reflected by the light guiding plate  3  and is directed toward the LCD panel assembly  8  but another part is leaked through the bottom surface of the light guiding plate  3  as to shown in  FIGS. 1 through 3 . In  FIG. 1 , a reference symbol. “C” indicates a leakage light leaked toward the outside.  
         [0023]     Thus, if a part of the light is leaked through the bottom surface of the light guiding plate  3 , a light directed toward the LCD panel assembly  8  is insufficient naturally, so that an amount of the brightness that is necessary to display an image definitely is lacking.  
         [0024]     In order to overcome this problem, as shown in  FIG. 2 , there is further provided a reflection plate  11  for reproducing the leakage light leaked from the light guiding plate  3  while having a high reflectivity below the light guiding plate  3 .  
         [0025]     Thus, in the case that the light guiding plate and the reflection dots  3   d  are used, the aforementioned diffusion plate  6 , the prism sheet  9 , the reflection plate  11  and the like are additionally needed, so that the production costs increase substantially. The diffusion plate  6 , the prism sheet  9  and the reflection plate  11  are stacked and received in the named order in a receiving container (not shown), to thereby compose a so-called backlight assembly.  
         [0026]     While the aforementioned diffusion plate  6 , the prism sheet  9  and the reflection plate  11  enhance the optical uniformity of the light, a considerable amount of the light generated from the lamp  1  such as a CCFT lamp is consumed.  
         [0027]     Thus, in order to obtain a sufficient brightness necessary for the displaying of an image in the LCD, the amount of the light generated from the CCFT lamp I should increase considering a lost amount of the light in the backlight assembly. This means a substantial increase in power consumption.  
         [0028]     Furthermore, the diffusion plate  6 , the prism sheet  9  and the reflection sheet  11  act to increase the thickness of the LCD, as well as time spent in the assembly of the LCD and its production costs.  
       SUMMARY OF THE INVENTION  
       [0029]     Accordingly, it is a first object of the present invention to provide a, light guiding plate allowing a light generated from a lamp to have an optical distribution of a planar light source while allowing the light to be incident toward an LCD panel assembly with a high brightness.  
         [0030]     It is a second object of the invention to provide a method for manufacturing a light guiding plate in which brightness and uniformity in the brightness are enhanced.  
         [0031]     It is a third object of the invention to provide an LCD in which a structure of a light guiding plate is altered, thereby substantially enhancing the brightness while diminishing the thickness and the volume of the light guiding plate.  
         [0032]     To accomplish the first object of the invention, there is provided a light guiding plate disposed below an LCD panel. The light guiding plate allows a light having an optical distribution of a planar light source to be supplied toward the LCD panel. The light guiding plate includes a light input face, into which the light is inputted, and a light reflection face, which is adjacent to the light input face. The light reflection face has at least one brightness enhancement recess and a light output face that faces the light reflection face. The brightness enhancement recess is formed at the light reflection face of a body of the light guiding plate. The body of the light guiding plate includes at least two side faces having the light input face. The brightness enhancement recess reflects toward the light output face a light that is inputted through the light input face and is reflected by the side faces, to enhance brightness.  
         [0033]     To accomplish the first object of the present invention, there is also provided a light guiding plate disposed below an LCD panel. The light guiding plate allows a light having an optical distribution of a planar light source to be supplied toward the LCD is panel. The light guiding plate has a light input face, into which the light is inputted, a light reflection face, which is adjacent to the light input face, and a light output face facing the light reflection face. The light output face includes at least one light concentration pattern formed in succession in a first direction. The light concentration pattern has a profile in a prism shape.  
         [0034]     To accomplish the second object of the present invention, there is provided a method for manufacturing a light guiding plate. In the above method, a photosensitive film is coated on a base substrate. The photosensitive film is exposed by using lights having various wavelengths and then developed to form at least one polygonal pyramid shaped recess with a certain depth from the surface of the photosensitive film. A metal material is deposited on the photosensitive film including the polygonal pyramid-shaped recess to form a metal substrate and then the metal substrate is separated from the photosensitive film. The separated metal substrate is loaded into an inner space between an upper mold and a lower mold, and then a material for forming the light guiding plate is supplied into the inner space.  
         [0035]     To accomplish the second object of the present invention, there is also provided a method for manufacturing a light guiding plate with an enhanced brightness. In the above method, a photosensitive film is coated on a base substrate to a selected thickness. The photosensitive film is partially exposed and developed to partially removing an exposed portion of the photosensitive film, thereby forming a protruded portion at a non-exposed portion of the photosensitive film. At least one polygonal pyramid-shaped recess is formed at a remaining portion of the photosensitive film except for the protruded portion. A metal material is deposited on the protruded portion and the recess to form a metal substrate. The metal substrate is separated from the photosensitive film. The separated metal substrate is loaded into an inner space between an upper mold and a lower mold and then a material for forming the light guiding plate is supplied into the inner space.  
         [0036]     To accomplish the second object of the present invention, there is also provided a method for manufacturing a light guiding plate with an enhanced brightness. In the above method, a first injection molding substrate includes an upper mold having a prism-shaped pattern therein. The prism-shaped pattern has a V-shaped profile. A plurality of prism-shaped patterns are repeatedly formed in parallel with a first direction. A material for the formation of the light guiding plate is injected into a space which is formed by coupling the upper mold and a lower mold of the first injection molding substrate to form a first light guiding plate on which a first light concentration pattern is formed. A second injection molding substrate includes an upper mold having a triangular pyramid pattern therein. The triangular pyramid pattern having a V-shaped profile and the triangular pyramid patterns are repeatedly formed in parallel with a second direction which is different from the first direction. The first light guiding plate is placed at the lower mold. The upper mold and the lower mold are coupled to each other, and a material for the formation of a second light guiding plate is supplied into a to space between the second injection molding substrate and an upper face of the first light guiding plate to form the second light guiding plate.  
         [0037]     To accomplish the third object of the present invention, there is provided an LCD. The LCD includes: an LCD panel assembly for displaying an image by controlling a liquid crystal layer; and a backlight assembly. The backlight assembly includes: (i) a lamp assembly for supplying a light, (ii) a light guiding plate having: a light input face into which the light is inputted; a light reflection face having at least one brightness enhancement means; and a light output face allowing the light to be outputted from the brightness enhancement means, wherein the brightness enhancement recess reflects toward the light output face the light which is inputted through the light input face and is reflected by the side faces, to enhance brightness, (iii) a light path control film facing the light output face and (iv) a reflection plate formed below the light guiding plate.  
         [0038]     To accomplish the third object of the present invention, there is also provided an LCD. The LCD comprises: an LCD panel assembly for displaying an image by controlling a liquid crystal layer; and a backlight assembly. The backlight assembly includes: (i) a lamp assembly for supplying a light, and (ii) a light guiding plate having: a light input face into which the light is input; a brightness enhancement means for reflecting at least one a second light having a different progress direction than an input direction of the light toward the LCD panel assembly to enhance brightness; a light reflection face having a brightness enhancement protrusion for preventing the light from being leaked; and a light output face allowing the light to be outputted from the brightness enhancement means and having a brightness concentration means formed in the light output face. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0039]     The above objects and other advantages of the present invention will become more apparent by describing in detail the preferred embodiments thereof with reference to the accompanying drawings, in which:  
         [0040]      FIG. 1  is a schematic view for describing operation of the light guiding plate and the reflection dots in a conventional LCD;  
         [0041]      FIG. 2  is a schematic view for describing operation of the diffusion sheet for diffusing light irradiated from the light guiding plate in a conventional LCD;  
         [0042]      FIG. 3  is a schematic view for describing operation of an optical sheet including the diffusion sheet and the prism sheet, and the reflection plate in a conventional LCD;  
         [0043]      FIG. 4  is a schematic view for describing optical distributions of the light irradiated respectively from the conventional light guiding plate, the diffusion sheet and the prism sheet;  
         [0044]      FIG. 5  is a rear perspective view of the light guiding plate in accordance with the first embodiment of the present invention;  
         [0045]      FIG. 6  is an enlarged view of the portion “D” in  FIG. 5 ;  
         [0046]      FIG. 7  is a sectional view taken along the line VII-VII of  FIG. 6 ;  
         [0047]      FIG. 8  is a conceptive view for describing an operation of the brightness enhancement recess in accordance with the first embodiment of the present invention;  
         [0048]      FIG. 9  is a conceptive view for describing an optical path of the brightness enhancement recess in accordance with the first embodiment of the present invention;  
         [0049]      FIG. 10  is a conceptive view for showing a mirror reflection result due to the to brightness enhancement recess in accordance with the first embodiment of the present invention;  
         [0050]      FIGS. 11A through 11G  are views for illustrating a manufacturing method of the brightness enhancement recess in accordance with the first embodiment of the present invention;  
         [0051]      FIG. 12  is an exploded perspective view of an LCD to which the light guiding plate in accordance with the first embodiment of the present invention is applied;  
         [0052]      FIG. 13 a  rear perspective view of a light guiding plate with a curved brightness enhancement recess in accordance with the second embodiment of the present invention;  
         [0053]      FIG. 14  is an enlarged view of the portion “G” in  FIG. 13 ;  
         [0054]      FIG. 15  is a cross-sectional view of the curved brightness enhancement recess in the light guiding plate of  FIG. 13 ;  
         [0055]      FIG. 16  is an enlarged view of the portion “H” in  FIG. 13  in which a light diffusion recess is further formed in the curved brightness enhancement recess in accordance with another embodiment of the present invention;  
         [0056]      FIG. 17  is a cross-sectional view of the curved brightness enhancement recess in the light guiding plate with the light diffusion recess of  FIG. 16 ;  
         [0057]      FIGS. 18A through 18G  are views for illustrating a method for forming the curved brightness enhancement recess with the light diffusion recess;  
         [0058]      FIG. 19  is an exploded perspective view of an LCD to which the light guiding plate is applied in accordance with the second embodiment of the present invention;  
         [0059]      FIG. 20  is a perspective view of the light guiding plate in accordance with another embodiment of the present invention;  
         [0060]      FIGS. 21A through 21F  are views illustrating a method for manufacturing the light guiding plate of  FIG. 20 ;  
         [0061]      FIG. 22  is a perspective view of the light guiding plate in accordance with 15 another embodiment of the present invention;  
         [0062]      FIGS. 23A and 23B  are views describing a method for manufacturing the light guiding plate of  FIG. 22 ;  
         [0063]      FIG. 24  is an exploded perspective view of an LCD to which the light guiding plate of  FIG. 22  is applied;  
         [0064]      FIG. 25  is an enlarged view of the portion “I” in  FIG. 13  in accordance with another embodiment of the present invention;  
         [0065]      FIG. 26  is a sectional view taken along a line in parallel with a light leakage preventive protrusion and the brightness enhancement recess in  FIG. 25 ;  
         [0066]      FIG. 27  an enlarged view of the light guiding plate in accordance with another embodiment of the present invention;  
         [0067]      FIG. 28  is a sectional view of the light guiding plate in  FIG. 27 ;  
         [0068]      FIGS. 29A through 29F  are views illustrating a method for manufacturing the light guiding plate with the light leakage preventive protrusion and the brightness enhancement recess; and  
         [0069]      FIG. 30  is an exploded perspective view of an LCD to which the light guiding plate with the light leakage preventive protrusion and the brightness enhancement recess. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0070]     Hereinafter, there are in detail described a light guiding plate, a method for manufacturing the light guiding plate and an LCD provided with the light guiding plate with reference to the accompanying drawings.  
         [0071]      FIG. 5  is a rear perspective view of a light guiding plate  700  that supplies a planar type light to an LCD panel in accordance with a first embodiment of the present invention.  
       Embodiment 1  
       [0072]     Referring to  FIG. 5 , a light guiding plate  700  has a structure of a flat plate type parallelepiped having no difference in thickness, or a wedge type parallelepiped whose thickness increases as it travels from one end to the other end, as it is viewed as a whole.  
         [0073]     The present embodiment describes a wedge type light guiding plate.  
         [0074]     Since the wedge type light guiding plate has a similar shape to the hexahedron, the wedge type light guiding plate has an upper face, a bottom face facing the upper face, and at least three side faces enclosing the upper face and the bottom face.  
         [0075]     In  FIG. 5 , there is shown a light guiding plate  700  having four side faces.  
         [0076]     For the convenience of the description, an upper face which is arranged to face an LCD panel is defined as a light output face  120 , a bottom face facing the light output face  120  is defined as a light reflection face  110 .  
         [0077]     Further, among the four side faces of the light guiding plate  700 , a side face where a lamp is established is especially defined as a light input face  130  and the remaining three side faces are respectively defined as a first side face  140 , a second side face  150  and a third face  160 .  
         [0078]     At this time, as shown in  FIG. 5 , a plurality of brightness enhancement recesses  
         [0079]      112  are formed throughout the entire surface of the light reflection face  110 .  
         [0080]     Each brightness enhancement recess  112  is in a matrix shape and their surface areas are varied depending on position of a lamp established adjacent to the light input face  130 .  
         [0081]     Specifically, the density of the brightness enhancement recess  112  is decided considering the area of the light input face  130 .  
         [0082]     More specifically, the density of the brightness enhancement recess  112  increases as it travels from the light input face  130  to the first side face  140  facing the light input face  130 .  
         [0083]      FIGS. 6 and 7  show the brightness enhancement recesses  112  formed in the light reflection face  110  in more detail.  
         [0084]     For instance, as shown in  FIG. 6 , which is an enlarged view of the section “D” from  FIG. 5 , the brightness enhancement recess  112  have a pyramidal prism shape having four side faces.  
         [0085]     While the present embodiment shows and describes a case of the pyramidal shaped recess as the brightness enhancement recess  112 , a polygonal cone having at least three side faces or a non-angular shaped cone can be selectively used.  
         [0086]     Hereinafter, the four side faces of each of the brightness enhancement recess  112  is respectively defined as a first side face  112   a , a second side face  112   b , a third side face  112   c  and a fourth side face  112   d.    
         [0087]     It is noted that the first face to third side face  140 ,  150 ,  160  and the light input face  130  of the light guiding plate  700  correspond to the first face to fourth side face  112   a ,  112   b ,  112   c ,  112   d  of the brightness enhancement recess  112 .  
         [0088]     More specifically, the light input face  130  of the light guiding plate  700  faces the first side face  112   a  of the brightness enhancement recess  112 , the first side face  140  of the light guiding plate  700  faces the second side face  112   b  of the brightness enhancement recess  112 , the second side face  150  of the light guiding plate  700  faces the third side face  112   c  of the brightness enhancement recess  112  and the third side face  160  of the light guiding plate  700  faces the fourth side face  112   d  of the brightness enhancement recess  112  to the highest degree.  
         [0089]     Thus, the four side faces  130 ,  140 ,  150 ,  160  of the light guiding plate  700  match with the four side faces  112   a ,  112   b ,  112   c ,  112   d  of the brightness enhancement recess  112 , so that brightness is substantially enhanced.  
         [0090]     Specifically, referring to  FIGS. 8 and 9 , the light generated from the lamp  200  is incident toward “a” direction through the light input face  130  of the light guiding plate  700  and is then reflected to have an optical distribution of a planar light source by the light reflection face  110  shown in  FIG. 9 .  
         [0091]     At this time, the light that has been incident through the light input face  130  from the lamp  200  has multiple progressive directions of “b” direction, which is a direction of a light reflected by the first side face  140  of the light guiding plate  700  facing the light input face  130 , “c” direction, which is a direction of a light reflected by the second side face  150 , which is placed adjacent to the light input face  130  and “d” direction, which is to a direction of a light reflected by the third side face  160 .  
         [0092]     Here, if the brightness enhancement recess  112  does not exist, the light that is input along the “a” direction, is reflected by the light reflection face  110  toward the light output face  120 . However, although the lights of the “b”, “c” and “d” directions are also reflected by the light reflection face  110  like the light of “a” direction, they do not have a progressive direction necessary for the displaying of an image, so that they are wasted.  
         [0093]     Meanwhile, if the brightness enhancement recess  112  is formed as in the present embodiment of the present invention, the lights that are input along the “a”, “b”, “c” and “d” directions, are reflected by the first to the fourth side faces  112   a  to  112   d  of the brightness enhancement recess  112 , and the reflected lights are directed towards the light output face  120 .  
         [0094]     The accompanying drawing of  FIG. 9  shows that the lights that are inputted in the “b”, “c” and “d” directions as wells as in the “a” direction are reflected by the  
         [0095]     brightness enhancement recess  112  and then are outputted to the outside of the light guiding plate through the light output face  120 .  
         [0096]     According to a simulation result, if the brightness enhancement recess  112  capable of utilizing the lights in the “b”, “c” and “d” directions as well as the “a” direction  5  is formed, the brightness is enhanced by 10% or more.  
         [0097]     The first side face  112   a  to the fourth side face  112   d  of the brightness enhancement recess  112  shown in  FIG. 6  to  FIG. 9  are mirror face-processed. This means that when the incident lights are reflected by the first side face  11   2   a  to the fourth side face  112   d  of the brightness enhancement recess  112 , these lights are mirror face reflected.  
         [0098]     Referring to  FIG. 10 , when the incident lights are reflected by the first side face  112   a  to the fourth side face  112   d  of the brightness enhancement recess  112 , a displayed picture  300  is viewed brighter or much more dark locally. In this case, a user&#39;s eye fatigue increases, so that the display characteristic is lowered.  
         [0099]      FIGS. 11A  to  11 G show a method for forming the brightness enhancement recess  112  of the first embodiment in the light reflection face  110  of the light guiding plate  700 .  
         [0100]     Referring to  FIG. 11A , a thick photoresist film (or photosensitive film)  420  is formed on a base substrate  410  by a spin coating method.  
         [0101]     After that, as shown in  FIG. 11 B , a micro lens  430  for concentrating an incident light is aligned over the photoresist film  420 .  
         [0102]     Thereafter, the light generated from a light source  440  is emitted onto the micro lens  430  to pass through the micro lens  430 . Then, the light passing through the micro  
         [0103]     lens  430  is irradiated onto the photoresist film  420  to partially expose the photoresist film  420  to the light.  
         [0104]     The light passing through the micro lens  430  has a quadrangular pyramid shape whose area decreases gradually as it goes from the micro lens  430  to a focused portion of the photoresist film  420 . Thus, the photoresist film  420  is exposed to have the same profile as the light irradiated onto the micro lens  430 .  
         [0105]     Subsequently, as shown in  FIG. 11C , the exposed photoresist film  420  is developed and thus a photoresist recess pattern  425  having the same profile as the brightness enhancement recess  112  is formed.  
         [0106]     Afterwards, as shown in  FIG. 1D , a metal layer  432  is deposited on the patterned photoresist film including the photoresist recess pattern  425  to a certain thickness by a sputtering method. The deposited metal layer  432  serves as a metal substrate having a metal protrusion  435  corresponding to the photoresist recess pattern  425 .  
         [0107]     is Thereafter, as shown in  FIG. 11 E , the patterned photoresist film  420  attached to the metal substrate  432  is removed by an ashing process. Next, the metal substrate  432  is attached on a lower mold  440  by turning upside down the metal substrate  432  of  FIG. 11 D  for the formation of the light guiding plate.  
         [0108]     Afterwards, as shown in  FIG. 11 F , an upper mold  450  for the formation of the light guiding plate is coupled to the lower mold  440 . Then, a liquid material  460  for the formation of the light guiding plate is injected into a space between the lower mold  440  and the upper mold  450  through an injection hole of the upper mold  450 . Thus, the light  
         [0109]     guiding plate  700  having the brightness enhancement recess  112  arranged at the light reflection face  110  is manufactured as shown in  FIG. 11 G .  
         [0110]      FIG. 12  is an exploded perspective view of an LCD to which the light guiding plate  700  having the aforementioned constitution is applied.  
         [0111]     The LCD  600  includes an LCD panel assembly  610  and a backlight assembly  660 .  
         [0112]     More particularly, the LCD panel assembly  610  includes: an LCD panel  603  provided with a thin film transistor (TFT) substrate  601 , a color filter substrate  602  and a liquid crystal layer between the TFT substrate  601  and the color filter substrate  602 ; and a driving module  604 ,  605 ,  606 ,  607  for driving the LCD panel  603 .  
         [0113]     In the meanwhile, the liquid crystal layer in the LCD panel assembly  610  functions to vary only the transmittance by an electric field as applied. Such a fact means that a light source having a high and uniform brightness should be provided in order to perform a display operation in the LCD panel assembly  610 .  
         [0114]     So as to satisfy this request, the backlight assembly  660  is established below the LCD panel  603 .  
         [0115]     The backlight assembly  660  in accordance with one embodiment of the present invention includes the light guiding plate  700  having the aforementioned brightness enhancement recess  112 , a lamp assembly  620  for providing the light incident face  130   
         [0116]     of the light guiding plate  700  with a light, an optical sheet  630  disposed on the light output face  120  (not shown) of the light guiding plate  700 , for enhancing the uniformity in the light passing through the light guiding plate  700 , and a reflection plate  640   
         [0117]     disposed below the light guiding plate  700 , for reproducing a leakage light leaked through the light guiding plate  700 .  
         [0118]     In  FIG. 12 , an unexplained reference numeral  650  is a receiving container.  
         [0119]     Table 1 shows difference between a constitution of a conventional backlight assembly and that of the backlight assembly provided in the first embodiment of the present invention.  
                               TABLE 1                                   Conventional Art   Items   1 St  Embodiment                           Establish   Prism sheet   Establish           Establish   Diffusion sheet   Establish           Establish   Light guiding   Establish           (Use of   plate   (Use ofbrightness           Reflection dots)       enhancement recess)           Establish   Reflection plate   Establish           Reference Datum   Brightness   10% enhancement           value       compared with                   reference datum                   value                      
 
         [0120]     Referring to Table 1, both the conventional backlight assembly and the backlight assembly  660  of the present invention include the optical sheet comprised of the prism sheet and the diffusion plate, the light guiding plate and the reflection plate. However, it can be noted that the light guiding plate  700  used in the backlight assembly  660  of the present invention has the brightness enhancement recess  112  unlike the light guiding plate of the conventional art and thereby the brightness is enhanced by about 10% or more compared with the conventional backlight assembly.  
         [0121]     Meanwhile, in the case that the structure of the brightness enhancement recess  112  formed in a matrix shape in the light guiding plate  700  is again modified, it can be prevented that an image displayed on the panel is viewed brighter or darker locally, and thus the displaying performance is lowered.  
         [0122]     Shown in  FIG. 13  is a rear perspective view of a light guiding plate  700  including a curved brightness enhancement recess  114  (not shown) in accordance with the second embodiment of the present invention. In order to prevent the lowering in the displaying performance due to occurrence of these local defects, the first to the fourth side face  114   a  to  14   d  of the light guiding plate  700  may be formed with a curvature in which the side faces are curved outwardly from the inner space of the brightness enhancement recess  112 , as shown in  FIG. 14 , which is an enlarged view of the portion “G” of  FIG. 13 .  
         [0123]     The curved side faces  114   a  to  114   d  of the brightness enhancement recess  114  allow an incident light to be reflected by the curved side faces  114   a  to  114   d  with a wider angle, so that the light diffusion is performed with the variety of the reflection paths as shown in the cross-sectional view of  FIG. 15 .  
         [0124]     Thus, in the case that the light is diffused through the curved side faces  114   a  to  114   d  of the brightness enhancement recess  114 , an image can be displayed with a high brightness and an enhanced light uniformity, so that a high quality image may be displayed.  
         [0125]     The above light guiding plate  700  with the brightness enhancement recess  114  having the curved side faces  114   a  to  114   d  may be manufactured by the same method as shown in  FIGS. 11A  to  FIG. 11 G  except for the side face portions.  
         [0126]     In order to form the side face portions  114   a  to  114   d  of the brightness enhancement recess  114  to have such the curvature, the wavelength of light used for the exposure of the photoresist film is precisely controlled.  
         [0127]     Meanwhile, so as to reinforce the diffusion ability in the brightness enhancement recess formed in the light guiding plate  700 , a plurality of light diffusion recesses  114   e  are formed in the side faces  11   4   a  to  11   4   d  of the brightness enhancement recess  114  as to shown in  FIG. 16  which is an enlarged view of the portion “H” from  FIG. 13 .  
         [0128]     Specifically, referring to  FIG. 17 , when it is assumed that the brightness enhancement recess is 100 μm wide by 100 μm long, at least one light diffusion recess  114   e  is formed with a width and a length, ranged from 15 μm to 20 μm at the side faces  114   a  to  114   d  of the brightness enhancement recess  114 .  
         [0129]     These light diffusion recesses  114   e  scatter the light diffusion reflected by the brightness enhancement recess  114  to further enhance the brightness uniformity.  
         [0130]     Here, the light diffusion recess  114   e  is formed to have a regular shape or an irregular shape. Also, a plurality of the light diffusion recesses  114   e  are formed to have a regular arrangement or an irregular arrangement.  
         [0131]     Next, there is described a method for manufacturing the light guiding plate having the brightness enhancement recess  114  in which the light diffusion recess  114   e  is formed with reference to the accompanying drawings of  FIG. 18A  to  FIG. 18G .  
         [0132]     First, as shown in  FIG. 18A , there is formed a thick photoresist film  820  on a base substrate  810  by a spin coating method.  
         [0133]     After that, as shown in  FIG. 18B , a micro lens  830  for concentrating an incident light is aligned over the photoresist film  820 .  
         [0134]     Thereafter, the light generated from a light source is emitted onto the micro lens  830  to pass through the micro lens  830 . Then, the light passing through the micro lens  830  is irradiated onto the photoresist film  820  to expose the photoresist film  820  to the light.  
         [0135]     The light passing through the micro lens  830  has a quadrangular pyramidal shape whose area decreases gradually as it goes from the micro lens  830  to a focused portion of the photoresist film  820 . Thus, the photoresist film  820  is exposed to have the same profile as the light irradiated onto the micro lens  830 .  
         [0136]     Subsequently, as shown in  FIG. 18C , the exposed photoresist film  820  is developed and thus a recess  825  having a polygonal cone shape, preferably, a 15 quadrangular pyramidal shape is formed.  
         [0137]     Thereafter as shown in  FIG. 18D , another micro lens  840  for forming the light diffusion recess  114   e  is aligned over the photoresist film  820  such that it corresponds to the recess  825 . The micro lens  840  includes a light shielding film formed throughout the entire area of one surface of the micro lens  840  and a plurality of openings formed in the light shielding film and having a dot shape in order to form the plurality of light diffusion recess in the side faces of the recess  825 . The light is again irradiated onto the side face of the recess  825  through the micro lens  840  to expose selected portions of the recess  825  of the photoresist film  820 . Then, the exposed portions are developed. As a result, another recess  827  for the formation of the light diffusion recess  114   e  is formed in the recess  825  as shown in  FIG. 18E .  
         [0138]     Afterwards, as shown in  FIG. 18F , a metal layer  850  is deposited on the patterned photoresist film including the recess  825  and  827  (not shown) to a predetermined thickness by a sputtering method. The deposited metal layer  850  serves as a metal substrate having protrusions corresponding to the recess  825  and  827 .  
         [0139]     Thereafter, as shown in  FIG. 18G , the patterned photoresist film  820  attached to the metal substrate  850  is removed by an ashing process. Then, the metal substrate  850  is attached onto a lower mold  860  by turning upside down the metal substrate  850  of  FIG. 18   f  for the formation of the light guiding plate.  
         [0140]     Afterwards, an upper mold  870  for the formation of the light guiding plate is coupled to the lower mold  860 . Then, a liquid material  880  for the formation of the light guiding plate is injected into a space between the lower mold  860  and the upper mold  870  through an injection hole of the upper mold  870 . Resultantly, the brightness enhancement recess  114  and the light diffusion recess  114   e  are both formed in the light reflection face  110  of the light guiding plate  700 .  
         [0141]      FIG. 19  is an exploded perspective view of an LCD  900  to which the light guiding plate  700  having the aforementioned brightness enhancement recess  114  and light diffusion recess  114   e  are applied.  
         [0142]     The LCD  900  includes an LCD panel assembly  910  and a backlight assembly  960 .  
         [0143]     More specifically, the LCD panel assembly  910  includes: an LCD panel  903  provided with a TFT substrate  901 , a color filter substrate  902  and a liquid crystal layer interposed between the TFT substrate  901  and the color filter substrate  902 ; and a driving module  904 ,  905 ,  906 ,  907  for driving the LCD panel  903 .  
         [0144]     Meanwhile, the liquid crystal layer in the LCD panel assembly  910  functions to vary only the transmittance by an electric field as applied. Such a fact means that a light source should be provided in order to perform a display operation in the LCD panel assembly  910 .  
         [0145]     So as to satisfy this request, the backlight assembly  960  is established below the LCD panel  903 .  
         [0146]     The backlight assembly  960  in accordance with one embodiment of the present invention includes the light guiding plate  700  having the brightness enhancement recess  112  provided with the brightness enhancement recess  114  and the light diffusion recess  114   e , a lamp assembly  920  for providing the light incident face  130  of the light guiding plate  700  with a light, at least one prism sheet  930  disposed on the light guiding plate  700 , for enhancing the visual angle, and a reflection plate  940  disposed below the light guiding plate  700 , for reproducing a leakage light leaked through the light guiding plate  700 .  
         [0147]     In  FIG. 19 , unexplained reference numeral  650  indicates a receiving container.  
         [0148]     Here, what is important is that the LCD  900  to which the light guiding plate  700  is applied is not affected on the deletion of the diffusion sheet between the upper surface of the light guiding plate  700  and the LCD panel assembly  910 . This is because the curved side faces  114   a  to  114   d  of the brightness enhancement recess  114  formed in the light reflection face  110  of the light guiding plate  700 , or the light diffusion recess  114   e  formed at the side faces  114   a  to  114   d  of the brightness enhancement recess  114 , performs the light diffusion function of the diffusion sheet.  
         [0149]     Table 2 shows differences between a constitution of a conventional backlight assembly and that of the backlight assembly of an embodiment of the present invention provided with the light guiding plate having both the curved side faces  114   a  to  114   d  and the light diffusion recess  114   e .  
                               TABLE 2                                   Conventional Art   Items   1 St  Embodiment                           Establish   Prism sheet   Establish           Establish   Diffusion plate   Not established           Establish   Light guiding   Establish           (Use of   plate   (Use of curved           Reflection dots)       brightness                   enhancement                   recess and light                   diffusion recess)           Establish   Reflection plate   Establish           Reference datum   Brightness   10% enhancement           value       compared with                   reference datum                   value                      
 
         [0150]     According to Table 2, both the conventional backlight assembly and the backlight assembly  660  of the present invention include the prism sheet  930 , the light guiding plate  700  and the reflection plate  940 , except for the diffusion plate. However, in the backlight assembly of the present invention, since the light diffusion is sufficiently performed by the brightness enhancement recess  114  and by the light diffusion recess  114   e  through the light guiding plate  700 , the display performance is not affected by the non-existence of the diffusion plate. Also, the brightness is enhanced by about 10% or more compared with the conventional backlight assembly.  
       Embodiment 2  
       [0151]     The light guiding plate  700  described in the first embodiment functions to enhance the uniformity and brightness of the light input into the light guiding plate  700  by forming the brightness enhancement recess  114  and/or the light diffusion recess  114   e.    
         [0152]     However, the second embodiment modifies the structure of the light output face  120  of the light guiding plate  700  such that it secures a front visual angle of the light with an enhanced uniformity due to the brightness enhancement recess  114 .  
         [0153]     Specifically, as shown in  FIG. 20 , a light concentration pattern  172  is formed at the light output face  120  of the light guiding plate  700 . The light concentration pattern  172  is in parallel with the y-axis direction of an x-y-z coordinate as shown. There is at least one light concentration pattern  172 , and it may be repeated in succession. The light concentration pattern  172  has a structure in which a plurality of prisms are arranged parallel to each other.  
         [0154]     The light concentration pattern  172  functions to vary the progressive direction of the light, which is incident into the light output face  120  and does not have a constant directionality, toward a direction in which the visual angle is improved. At this time, the pitches in the light concentration pattern  172  and the pixel patterns of the LCD panel are precisely controlled such that a condition generating Moire phenomenon is not satisfied.  
         [0155]     Hereinafter, there is described a method for forming the light guiding plate  700  having the light concentration pattern  172  formed in the light reflection face  120  and the brightness enhancement recess  117  formed in the light reflection face  110  with reference to, the accompanying drawings of  FIG. 21A  to  FIG. 21 G .  
         [0156]     First, as shown in  FIG. 21A , a thick photoresist film  841  is formed on a base substrate  840  having a plate shape by a spin coating method.  
         [0157]     After that, as shown in  FIG. 21 B , a micro lens (not shown) is aligned over the photoresist film  841  and the photoresist film  841  is exposed to the light generated from a light source and passing through the micro lens, so that one or more recesses  843 , having a shape corresponding to the brightness enhancement recesses  114 , are formed on a top of the photoresist film  841 .  
         [0158]     Afterwards, as shown in  FIG. 21C , a dense metal film  845  is formed on the photoresist film  841  including the recess  843  to a certain thickness by a sputtering method. The deposited metal layer  845  serves as a metal substrate having a metal protrusion pattern  845   a  corresponding to the brightness enhancement recess  114 .  
         [0159]     Thereafter, as shown in  FIG. 21D , the metal substrate  845  attached on the patterned photoresist film  841  is separated from the photoresist film  841  and is fixed on a selected position of a lower mold  846  such that the metal protrusion pattern  845   a  is directed upwards.  
         [0160]     Afterwards, as shown in  FIG. 21 E , an upper mold  847  for the formation of the light guiding plate is coupled to the lower mold  846 . Then, a liquid material  848  for the formation of the light guiding plate  700  is injected into a space between the lower mold  846  and the upper mold  847  through an injection hole of the upper mold  847 , as shown in  FIG. 21E . Resultantly, the manufactured light guiding plate  700  has a V-shaped light concentration pattern  172  formed in the light output face  120  and the brightness enhancement recess  114  formed in the light reflection face, as shown in  FIG. 21 F .  
         [0161]     Then, since the light concentration pattern  172  of the manufactured light guiding plate  700  is in parallel with the y-axis direction, a light having a path parallel to the z-y plane of the x-y-z coordinate shown in  FIG. 20  changes its progressive path into a direction for improving the visual angle.  
         [0162]     However, it is noted that it is very difficult to change the progressive path of the light parallel to the z-y plane.  
         [0163]     To this end, there is provided an embodiment for improving the visual angle of the light having a progressive path parallel to the z-y plane.  
         [0164]      FIG. 22  is a perspective view of a light guiding plate  700  in accordance with another embodiment of the present invention.  
         [0165]     Referring to  FIG. 22 , a light concentration pattern  172  is formed at the light output face  120  of the light guiding plate  700 . The light concentration pattern  172  is in parallel with the y-axis direction, is repeated along the x-axis direction and has a profile of a prism shape.  
         [0166]     Further, a brightness concentration light guiding plate  190  may be formed on the light concentration pattern  172  of the light guiding plate  700 . The brightness concentration light guiding plate  190  has a bottom face with a first auxiliary light concentration pattern  192  engaged with the light concentration pattern  172  and an upper face with a second auxiliary light concentration pattern  194  which is in parallel with the x-axis direction, is repeated along the y-axis direction and has a V-shaped prism profile.  
         [0167]     The brightness concentration light guiding plate  190  and the light guiding plate  700  can be manufactured in an integrated structure by a mold or they can be manufactured independently and then be coupled to each other.  
         [0168]     When the light concentration pattern  172  of the light guiding plate  700  is engaged with the first auxiliary light concentration pattern  192  of the brightness concentration light guiding plate  190 , a fine space is allowed therebetween, which optimizes the refractivity of the light.  
         [0169]     Unlike the above, while the brightness concentration light guiding plate  190  is manufactured as one body with the light guiding plate  700 , the light guiding plate  700  can be made of a different material from the brightness concentration light guiding plate  190 . At this time, an optical refractivity between the light passing through the light guiding plate  700  and the light passing through the brightness concentration light guiding plate  190  should be considered.  
         [0170]     Alternatively, while the brightness concentration light guiding plate  190  is manufactured as one body with the light guiding plate  700 , the light guiding plate  700  can be made of the same material as the brightness concentration light guiding plate  190 .  
         [0171]     Hereinafter, there is described a method for manufacturing the brightness concentration light guiding plate  190  as one body with the light guiding plate  700  with reference to the accompanying drawings of  FIG. 21A  to  FIG. 21F ,  FIG. 23A  and  FIG. 23B .  
         [0172]     First, the processes are performed in the same manner as described in  FIG. 21A  through  FIG. 21 F  to manufacture a light guiding plate  700  having a light output face  120  with the light concentration pattern  172  and a light reflection face with the brightness enhancement recess  114 .  
         [0173]     After that, as shown in  FIG. 23A , the manufactured light guiding plate  700  is fixed on a lower mold  880  and then an upper mold  890  is coupled to the lower mold  880 .  
         [0174]     At this time, an additional plate having a direction different from that of the light concentration pattern  172 , preferably perpendicular to the light concentration pattern  172 , and having a prism shape is established below the upper mold  890 .  
         [0175]     In a state that the upper mold  890  is coupled to the lower mold  880 , a material  190   a  for the formation of the brightness concentration light guiding plate  190  is injected into a space between the upper mold  890  and the lower mold  880  as shown in  FIG. 23A . Through the above process, the brightness concentration light guiding plate  190  is integrally formed as one body with the light guiding plate  700  on the light guiding plate  700  as shown in  FIG. 23B .  
         [0176]     At this time, the material  190   a  for the formation of the brightness concentration light guiding plate  190  may be the same as a material of the light guiding plate  700  or it may be different from the material of the light guiding plate  700 .  
         [0177]      FIG. 24  is an exploded perspective view of an LCD  1000  to which the light guiding plate  700  having the brightness concentration light guiding plate  190  manufactured by the combination of the first embodiment and the second embodiment is applied.  
         [0178]     The LCD  1000  includes an LCD panel assembly  1100  and a backlight assembly  1200  as a whole.  
         [0179]     More specifically, the LCD panel assembly  1100  includes: an LCD panel  1130  provided with a TFT substrate  1110 , a color filter substrate  1120  and a liquid crystal layer interposed between the TFT substrate  1110  and the color filter substrate  1120 ; and a driving module  1140 ,  1150 ,  1160 ,  1170  for driving the LCD panel  1130 .  
         [0180]     Meanwhile, the liquid crystal layer in the LCD panel assembly  1100  functions to vary only the transmittance by an electric field as applied. Such a fact means that a light source should be provided in order to perform a display operation in the LCD panel assembly  1100 .  
         [0181]     So as to satisfy this request, the backlight assembly  1200  is established below the LCD panel  1130 .  
         [0182]     The backlight assembly  1200  in accordance with one embodiment of the present invention includes the light guiding plate  700 , which is manufactured by the combination of the first embodiment and the second embodiment, a lamp assembly  1210  for providing the light incident face  130  of the light guiding plate  700  with a light, a reflection plate  1220  disposed below the light guiding plate  700 , for reproducing a leakage light leaked through the light guiding plate  700  and a receiving container  650  for receiving these elements.  
         [0183]     In the LCD  1000  to which the light guiding plate  700  manufactured by the combination of the first embodiment and the second embodiment is applied, an optical sheet comprised of a diffusion sheet and a prism sheet might not be disposed between the upper face of the light guiding plate  700  and the LCD panel assembly  1100 . This is because the curved side faces  114   a  to  114   d  of the brightness enhancement recesses  114  formed in the light reflection face  110  of the light guiding plate  700 , the light diffusion recess  114   e  formed at the side faces  114   a  to  114   d  of the brightness enhancement recess  114 , the light concentration pattern  172  formed at the light output face  120  of the light guiding plate  700  and the brightness concentration light guiding plate  190  perform the light diffusion function instead of the diffusion sheet.  
         [0184]     Table 3 shows the differences between a constitution of the conventional backlight assembly and that of the backlight assembly provided with the light guiding plate  700  manufactured by the combination of the first embodiment and the second embodiment of the present invention.  
                               TABLE 3                                   Conventional Art   Items   1 St  Embodiment                           Establish   Prism sheet   Not established           Establish   Diffusion plate   Not established           Establish   Light guiding   Establish           (Use of   plate   (Use of curved           Reflection dots)       brightness enhancement                   recess, light diffusion                   recess and light                   concentration pattern)           Establish   Reflection plate   Establish           Reference datum   Brightness   10% enhancement           value       compared with reference                   datum value                      
 
       Embodiment 3  
       [0185]     The aforementioned first and second embodiments describe the light guiding plate  700  functioning to enhance the uniformity and brightness of the light input into the light guiding plate  700  by forming the brightness enhancement recess  114  in the light reflection face, altering shape of the brightness enhancement recess  114 , forming the light diffusion recess  114   e  in the brightness enhancement recess  114  and forming the light concentration pattern  172  in the light output face  120  of the light guiding plate  700 .  
         [0186]     Then, according to the aforementioned first and second embodiment, most of the light that is incident through the light input face of the light guiding plate  700  is reflected by the brightness enhancement recess formed at the light reflection face but a part of the incident light is not reflected by the light reflection face  110  of the light guiding plate  700  but is leaked through the light reflection face  110 , so that lowering in the brightness occurs.  
         [0187]     Accordingly, the present embodiment discloses a light guiding plate  700  capable of minimizing a light amount leaked through the light reflection face  110  and allowing all light to be reflected by the light reflection face  110  of the light guiding plate  700  without using the reflection plate.  
         [0188]     Referring to  FIGS. 13, 14 ,  25  and  26 , in a state that the brightness enhancement recess  114  is formed in the light reflection face  110  of the light guiding plate  700  in a matrix configuration, a brightness enhancement protrusion  116  is formed along a column direction at the surface of the light reflection face  110  between the brightness enhancement recesses  114  arranged in the column direction.  
         [0189]     The brightness enhancement protrusion  116  has a polygonal pyramidal shape, preferably, in at least a triangular pyramidal shape. Further, it may have a cone shape.  
         [0190]     As shown in  FIG. 26 , the brightness enhancement protrusion  116  allows an incident light, which is not yet reflected by the brightness enhancement recesses  114  and are leaked, to be reflected by mirror faces of the brightness enhancement protrusion  116  at least one time and to progress toward the light output face  120 , thereby preventing the incident light from being leaked to a maximum degree.  
         [0191]     Preferably, this brightness enhancement protrusion  116  is formed between the brightness enhancement recesses  114  arranged in the column direction in one column as shown in  FIG. 25  or in at least two columns as shown in  FIGS. 27 and 28 .  
         [0192]     Here, if the peak portion of the brightness enhancement protrusion  116  is acutely processed, the brightness enhancement protrusion  116  itself is damaged or it damages other components. To this end, the peak portion of the brightness enhancement protrusion  116  is preferably processed to have a round shape.  
         [0193]     Meanwhile, the brightness enhancement protrusion  116  minimizes the light amount leaked through the light reflection face  110  of the light guiding plate  700  but it does not shield the leaked light completely.  
         [0194]     Considering this fact, a light reproduction thin film  119  for reproducing light is further formed below the light reflection face  110  in the light guiding plate  700  of the present embodiment.  
         [0195]     The light reproduction thin film  119  can be made of any material if the material has an excellent light reflectivity. For an example, metal or synthetic resin can be used as the material of the light reproduction thin film  119 .  
         [0196]      FIGS. 29A  to  FIG. 29F  are sectional views describing a method for forming the brightness enhancement recess  114  and the brightness enhancement protrusion  116  in a light guiding plate.  
         [0197]     Referring to  FIG. 29A , a photoresist film  882  is formed on a base substrate  880   5  to a predetermined thickness.  
         [0198]     Referring to  FIG. 29B , a mask  884  is aligned over the photoresist film  882  and the photoresist film  882  is exposed using the mask  884  such that the light passing through the mask  884  arrives only at a predetermined portion but the light does not arrive at the remaining portion.  
         [0199]     At this time, the intensity of the used light is controlled such that a protrusion  883  formed in the photoresist film  882  has the same height as the brightness enhancement protrusion  883 .  
         [0200]     After that, the exposed portions of the photoresist film  882  are developed, so that the protrusions having the same shape as the brightness enhancement protrusion  883 . are formed at the specific positions.  
         [0201]     Thereafter, as shown in  FIG. 29C , a recess  885  having the same shape and function as the brightness enhancement recess  114  provided in the first embodiment or the second embodiment is formed in the resultant photoresist film  882  having the protrusion  883 .  
         [0202]     Afterwards, as shown in  FIG. 29D , a dense metal film  886  is deposited on the resultant photoresist film  882  having the recess  885  and the protrusion  883 . The metal film  886  serves as a metal substrate  886 .  
         [0203]     After that, as shown in  FIG. 29E , the metal substrate  886  attached on the patterned photoresist film  882  is separated from the photoresist film  882  and is fixed on a selected position of a lower mold  887  such that the metal protrusion pattern  845   a  is directed upwards.  
         [0204]     Afterwards, an upper mold  888  is coupled to the lower mold  887 . Then, a liquid material  889  for the formation of the light guiding plate  700  is injected into a space between the lower mold  887  and the upper mold  888  through an injection hole of the upper mold  888 , as shown in  FIG. 29E . As a result of the molding, the light guiding plate  700  is obtained as shown in  FIG. 29F . Then, on a surface of the light guiding plate  700 , which makes contact with the metal substrate  886  in  FIG. 29E , a light reproduction thin film  119  is formed.  
         [0205]      FIG. 30  is an exploded perspective view of an LCD  1200  to which the light guiding plate  700  manufactured by the combination of the first embodiment to the third embodiment is applied.  
         [0206]     Referring to  FIG. 30 , the LCD  1200  includes an LCD panel assembly  1210  and a backlight assembly  1260  as a whole.  
         [0207]     More specifically, the LCD panel assembly  1210  includes: an LCD panel  1204  provided with a TFT substrate  1201 , a color filter substrate  1203  and a liquid crystal layer interposed between the TFT substrate  1201  and the color filter substrate  1203 ; and a driving module  1206 ,  1207 ,  1208 ,  1209  for driving the LCD panel  1204 .  
         [0208]     Meanwhile, the liquid crystal layer in the LCD panel assembly  1210  functions to vary only the transmittance by an electric field as applied. Such a fact means that a light source should be provided in order to perform a display operation in the LCD panel assembly  1210 .  
         [0209]     So as to satisfy this request, the backlight assembly  1260  is established below the LCD panel  1204 .  
         [0210]     The backlight assembly  1206  in accordance with the third embodiment of the present invention includes the light guiding plate  700  with the light concentration pattern formed at the light output face, the brightness enhancement recess  114  formed at the light reflection face and the light diffusion recess, and a lamp assembly  1230  for providing the light incident face  130  of the light guiding plate  700  with a light. There is also included a receiving container  650  for receiving all these elements.  
         [0211]     In the LCD  1200  to which the light guiding plate  700  manufactured by the combination of the first embodiment to the third embodiment is applied, the reflection plate as well as an optical sheet comprised of a diffusion sheet and a prism sheet might not be disposed on the upper face of the light guiding plate  700  or below the bottom face of the light guiding plate  700  in order to display an image with high and uniform brightness.  
         [0212]     This is because the curved side faces  114   a  to  114   d  of the brightness enhancement recess  114  formed in the light reflection face  110  of the light guiding plate  700 , the light diffusion recess  114   e  formed at the side faces  114   a  to  114   d  of the brightness enhancement recess  114 , the light concentration pattern  172  formed at the light output face  120  of the light guiding plate  700 , the brightness concentration light guiding plate  190  and the light reproduction thin film  119  formed at the light reflection face of the light guiding plate  700  perform the light diffusion and reflection functions instead of the optical sheet and the reflection plate, as described in the first to third embodiments.  
         [0213]     Table 4 shows differences between a constitution of the conventional backlight assembly and that of the backlight assembly provided with the light guiding plate  700  manufactured by the combination of the first embodiment to the third embodiments of the present invention.  
                               TABLE 4                                   Conventional Art   Items   1 St  Embodiment                           Establish   Prism sheet   Not established           Establish   Diffusion plate   Not established           Establish   Light guiding   Establish           (Use of   plate   (Use of curved           Reflection dots)       brightness enhancement                   recess, light diffusion                   recess, light                   concentration pattern,                   brightness enhancement                   protrusion and light                   reproduction thin film)           Establish   Reflection plate   Not established           Reference datum   Brightness   10% enhancement           value       compared with                   reference datum value                      
 
         [0214]     According to Table 4, in the case that the light guiding plate  700  manufactured by the combination of the first embodiment to third embodiments disclosed above is used, the prism sheet, the diffusion sheet and the reflection plate are unnecessary, so that the thickness of the LCD is substantially decreased.  
         [0215]     Also, the brightness enhancement recess  114 , the light diffusion recess, the light concentration pattern, the brightness enhancement protrusion  116  and the light reproduction film  119  formed in the light guiding plate  700  minimize the light loss, so that brightness is enhanced by about 10% or more in comparison with the conventional backlight assembly.  
         [0216]     As described above, the present invention changes the structure of the light guiding plate  700 , to thereby enhance brightness of the light supplied to the LCD panel assembly  1210  to a considerable degree. Also, uniformity in the light is considerably enhanced.  
         [0217]     Further, the light guiding plate  700  of the present invention does not require the diffusion sheet for enhancing the uniformity in the light supplied into the conventional LCD assembly, so that an LCD, which is slimmer in thickness, lighter in weight, simplified in the assembly process, and decreased in the number of the elements may be obtained.  
         [0218]     Furthermore, the light guiding plate  700  of the present invention does not require the reflection plate for reproducing the light leaked through the conventional light guiding plate, so that an LCD, which is slimmer in thickness, lighter in weight, simplified in the assembly process, and decreased in the number of the elements may be obtained.  
         [0219]     Moreover, the light guiding plate  700  of the present invention does not require any of the diffusion sheet, the prism sheet and the reflection plate, so that an LCD, which is slimmer in thickness, lighter in weight, simplified in the assembly process, and decreased in the number of the elements may be obtained.  
         [0220]     Also, the light guiding plate  700  of the present invention does not require the optical sheets, so that production costs are decreased substantially.  
         [0221]     While the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.