Abstract:
A backlight assembly and an LCD apparatus capable of reducing power consumption and increasing brightness of a light. The backlight assembly includes a light guide plate for receiving an external light and an artificial light, a first receiving container for receiving the light guide plate and supplying the artificial light to the light guide plate, and a second receiving container for supplying the external light to the light guide plate, the second receiving container comprising an light side wall inclined to the light guide plate. The LCD panel assembly displays images using the external light and artificial light from the light guide plate.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a backlight assembly and an LCD (Liquid Crystal Display) apparatus, and more particularly to a backlight assembly capable of reducing power consumption and increasing brightness of a light and an LCD apparatus having the same.  
           [0003]    2. Description of the Related Art  
           [0004]    LCD apparatuses typically display information such as a character, a still picture, and a moving picture by using a liquid crystal in which light transmittance is varied in response to an intensity of an electric field. The LCD apparatuses perform display operation using a light, for example, an external light such as sunshine, an illumination, etc., or an artificial light.  
           [0005]    LCD apparatuses include reflective LCD apparatuses and transmissive LCD apparatuses. The reflective LCD apparatuses display images using a reflective electrode in which sunshine or illumination is reflected to a liquid crystal. However, the reflective LCD apparatuses may not display the images where an amount of the external light is not enough to display the images.  
           [0006]    The transmissive LCD apparatuses display images using a transparent electrode which transmits the artificial light generated by consuming an electric energy. The transparent electrode is made of ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). Since the transmissive LCD apparatuses use only the artificial light to display the images, the transmissive LCD apparatuses consume a lot of power.  
           [0007]    Recently, transreflective LCD apparatuses have been developed so as to solve disadvantages of the reflective LCD apparatuses and transmissive LCD apparatuses. The transreflective LCD apparatuses comprise a transparent electrode and a reflective electrode. The reflective electrode of the transreflective LCD apparatuses is disposed on the transparent electrode and includes an opening to partially expose the transparent electrode. The transreflective LCD apparatuses display images using an external light where an amount of the external light is sufficient for such display, while the apparatuses display the images using an artificial light where an amount of the external light is insufficient for display purposes.  
           [0008]    However, the transreflective LCD apparatuses have a lower brightness as compared with those of the reflective LCD apparatuses and transmissive LCD apparatuses, while the transreflective LCD apparatuses can display images regardless of a presence of the external light.  
         SUMMARY OF THE INVENTION  
         [0009]    The present invention provides a backlight assembly capable of reducing power consumption and increasing brightness of a light.  
           [0010]    The present invention also provides an LCD apparatus having the backlight assembly. According one embodiment of the invention, a backlight assembly comprises a light guide plate comprising a first side surface for receiving an external light, a second side surface for receiving an artificial light, a third side surface and a fourth side surface for connecting the first side surface to the second side surface, a light reflecting surface for reflecting the external light and the artificial light, and a light emitting surface facing the light reflecting surface; a first receiving container for receiving the light guide plate and for supplying the artificial light to the second surface, the first receiving container comprising first to third sidewalls for covering the second to fourth side surfaces of the light guide plate; and a second receiving container having a bottom surface, fourth to sixth sidewalls for covering the first to third sidewalls, and a lighting sidewall for supplying the external light to the first surface, wherein the fourth to sixth sidewalls are extended from the bottom surface, and wherein the lighting sidewall is extended from the bottom surface, inclined with respect to the first side surface and connected between fifth and sixth sidewalls.  
           [0011]    According to another embodiment of the present invention, a backlight assembly comprises a light guide plate comprising an external light-lighting body, the external light-lighting body comprising a light reflecting side surface for reflecting an external light from a first direction to a second direction, a light receiving surface for receiving an artificial light from a third direction, a light reflecting surface for reflecting the external light and artificial light to a fourth direction, at least one side surface adjacent to the light receiving surface, and a light emitting surface for emitting the external light and the artificial light having the fourth direction; a first receiving container comprising a first sidewall for covering the light receiving surface and the at least one side surface, wherein the first receiving container supplies the artificial light to the light receiving surface; a second receiving container comprising a bottom surface, a second sidewall extended from the bottom surface, and a lighting sidewall extended from the bottom surface and connected to the second sidewall, wherein the lighting sidewall is inclined with respect to the bottom surface; and a light reflecting means disposed over the lighting sidewall and bottom surface.  
           [0012]    According to a further of the present invention, an LCD apparatus comprises a backlight assembly comprising a light guide plate for receiving an external light and an artificial light in different directions, a first receiving container for receiving the light guide plate and supplying the artificial light to the light guide plate, wherein the second receiving container comprises an lighting sidewall being inclined with respect to the light guide plate; an LCD panel assembly for converting the external light and artificial light into an image light having image information; and a chassis comprising a chassis body for exposing an effective display area of the LCD panel assembly and an external light-inducting window disposed on a portion of the chassis body corresponding to the lighting sidewall, wherein the chassis is combined to the second receiving container so as to fix the LCD panel assembly to the second receiving container.  
           [0013]    Advantageously, the backlight assembly and LCD apparatus according to the present invention uses both an external light and an artificial light to display the image. Thus, to the backlight assembly and LCD apparatus may reduce power consumption and increase brightness of the light. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    The above and other advantages of the present invention will become readily apparent by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:  
         [0015]    [0015]FIG. 1A is an exploded perspective view showing a backlight assembly according to a first embodiment of the present invention;  
         [0016]    [0016]FIG. 1B is a cross-sectional view taken along the line II-II for showing the light guide plate shown in FIG. 1A;  
         [0017]    [0017]FIG. 1C is a cross-sectional view taken along the line III-III for partially showing the first receiving container shown in FIG. 1A;  
         [0018]    [0018]FIG. 2 is a cross-sectional view taken along the line IV-IV for showing the second receiving container shown in FIG. 1;  
         [0019]    [0019]FIG. 3 is an exploded perspective view showing a backlight assembly according to a second embodiment of the present invention;  
         [0020]    [0020]FIG. 4 is a perspective view showing a light guide plate according to a third embodiment of the present invention;  
         [0021]    [0021]FIG. 5 is a cross-sectional view taken along the line V-V for showing the light guide plate shown in FIG. 4;  
         [0022]    [0022]FIG. 6 is an exploded perspective view showing a backlight assembly according to a fourth embodiment of the present invention;  
         [0023]    [0023]FIG. 7 is an exploded perspective view showing an LCD apparatus according to a fifth embodiment of the present invention;  
         [0024]    [0024]FIG. 8 is a cross-sectional view showing the LCD panel assembly shown in FIG. 7;  
         [0025]    [0025]FIG. 9 is a cross-sectional view showing the LCD apparatus shown in FIG. 7; and  
         [0026]    FIGS.  10  to  12  are schematic views showing an LCD apparatus according to a sixth embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0027]    Embodiment 1  
         [0028]    [0028]FIG. 1A is an exploded perspective view showing a backlight assembly according to a first embodiment of the present invention. FIG. 1B is a cross-sectional view taken along the line II-II for showing the light guide plate shown in FIG. 1A. FIG. 1C is a cross-sectional view taken along the line III-III for partially showing the first receiving container shown in FIG. 1A.  
         [0029]    Referring to FIGS. 1A to  1 C, a backlight assembly  900  comprises a lamp  340  for generating a light, a light guide plate  100  for guiding a light, a first receiving container  300  for receiving the light guide plate  100  and lamp  340 , and a second receiving container  400  for receiving the first receiving container  300  and for guiding an external light to the light guide plate  100 .  
         [0030]    The light guide plate  100  may have a rectangular parallelepiped. For example, the light guide plate  100  comprises first to fourth side surfaces  110 ,  120 ,  130  and  140 , a light reflecting surface  150 , and a light emitting surface  160 . The first side surface  110  faces the second side surface  120 , and the first and second side surfaces  110  and  120  are connected to each other by the third and fourth side surfaces  130  and  140 .  
         [0031]    The first side surface  110  receives the external light and the second side surface  120  receives an artificial light generated by consuming an electric energy. The external light supplied through the first side surface  110  and the artificial light supplied through the second side surface  120  are reflected from the light reflecting surface  150  and provided to the light emitting surface  160 .  
         [0032]    The third side surface  130  is provided with a first fixing protrusion  135  and the fourth side surface  140  is provided with a second fixing protrusion  145 . The first and second fixing protrusions  135  and  145  are partially protruded from the third and fourth side surfaces  130  and  140 , respectively. Each of the first and second fixing protrusions  135  and  145  has a pair of protrusions separated from each other.  
         [0033]    The first receiving container  300  comprises a first receiving container sidewall  350  for covering the second to fourth side surfaces  120 ,  130  and  140 , a first fixing recess  352   b  corresponding to the first fixing protrusion  135 , a second fixing recess  356   b  corresponding to the second fixing protrusion  145 .  
         [0034]    The first receiving container sidewall  350  includes a first sidewall  352  for covering the third side surface  130 , a second sidewall  354  for covering the second side surface  120 , and a third sidewall  356  for covering the fourth side surface  140 . The first, second and third sidewalls  352 ,  354  and  356  are stepped toward the third, second and fourth side surfaces  130 ,  120  and  140 , respectively. Each of the first and third sidewalls  352  and  356  is provided with first and second steps  352   c  and  356   c  on which the first and second fixing recesses  352   b  and  356   b  are disposed, respectively.  
         [0035]    The first receiving container  300  further includes a connection bar  358  for connecting the first and third sidewalls  352  and  356  to prevent an LCD panel from being moved. The connection bar  358  is disposed on the first and second steps  352   c  and  356   c  such that the connection bar  358  does not obstruct the light guide plate  100  to receive the external light through the first side surface  110 .  
         [0036]    As shown in FIG. 1C, the lamp  340  is adjacent to the second sidewall  354 . For example, the lamp  340  is received in a lamp receiving space  354   a  provided with the second sidewall  354  of the first receiving container  350 . The lamp  340  comprises a point light source such as a light emitting diode or a linear light source such as a cold cathode fluorescent lamp. The first receiving container  300  is received in the second receiving container  400 . The second receiving container  400  fixes the light guide plate  100  and lamp  340  in the first receiving container  300  as well as supplies the external light to the light guide plate  100 .  
         [0037]    Referring to FIG. 1A, the second receiving container  400  comprises a bottom surface  450 , fourth to sixth sidewalls  420 ,  430  and  440  (which correspond to the second, third and first sidewalls  354 ,  356  and  352 ), and a lighting sidewall  410 . The second receiving container  400  is made of a metal material and the bottom surface  450  has a plate shape having first to fourth edge portions  452 ,  454 ,  456  and  458 .  
         [0038]    The fourth to sixth sidewalls  420 ,  430  and  440  are extended from the second to fourth edge portions  454 ,  456  and  458 , respectively. For instance, the fourth to sixth sidewalls  420 ,  430  and  440  are extended until the heights of the fourth to sixth sidewalls  420 ,  430  and  440  are substantially identical to those of the first to third sidewalls  352 ,  354  and  356  of the first receiving container  300 . Accordingly, each of the fourth to sixth sidewalls  420 ,  430  and  440  of the second receiving container  400  covers the second, third and first sidewalls  354 ,  356  and  352  of the first receiving container  300 .  
         [0039]    The lighting sidewall  410  is disposed at the first edge portion  452  and faces the first side surface  110  of the light guide plate  100 . The lighting sidewall  410  is inclined with respect to the first side surface  110  toward the external.  
         [0040]    [0040]FIG. 2 is a cross-sectional view taken along the line IV-IV for showing the second receiving container shown in FIG. 1.  
         [0041]    Referring to FIG. 2, an inclined angle “α” of the lighting sidewall  410  with respect to the first side surface  110  is more than about 0 degree and less than about 90 degrees. The angle between the lighting sidewall  410  and the first side surface  110  is more than about 0 degree and less than about 90 degrees.  
         [0042]    An entire size of the backlight assembly  900  may be reduced. For example, a size of the second receiving container  400  is reduced according as the inclined angle “α” of the lighting sidewall  410  is closed to about 0 degree. Where the inclined angle “α” of the lighting sidewall  410  is closed to about 0 degree, an amount of the light supplied to the first side surface  110  through the lighting sidewall  410  decreases.  
         [0043]    The entire size of the backlight assembly  900  may be enlarged. For example, the size of the second receiving container  400  is enlarged according as the inclined angle “α” of the lighting sidewall  410  is closed to about 90 degrees. Where the inclined angle “α” of the lighting sidewall  410  is closed to about 90 degrees, the amount of the light supplied to the first side surface  110  through the lighting sidewall  410  increases.  
         [0044]    The inclined angle “α” of the lighting sidewall  410  is preferably set into an angle appropriate to reduce the size of the second receiving container  400  and increase the amount of the light supplied to the first side surface  110  of the light guide plate  110 . In preferred embodiments of the present invention, the inclined angle “α” of the lighting sidewall  410  with respect to the first side surface  110  is set into about 45 degrees.  
         [0045]    Where the inclined angle “α” is about 45 degrees, the lighting sidewall  410  may be easily damaged by an impact from the external. In order to maintain a shape of the lighting sidewall  410 , the first and the third sidewalls  352  and  356  are provided with first and second end portions  352   a  and  356   a,  respectively. Each of the first and second end portions  352   a  and  356   a  are inclined to the lighting sidewall  410  at an inverse angle of the inclined angle “α”.  
         [0046]    For instance, where the inclined angle “α” of the lighting sidewall  410  is about 145 degrees with respect to the bottom surface  450  of the second receiving container  400 , the first and second end portions  352   a  and  356   a  are formed to have an inclined angle of about 315 degrees with respect to the bottom surface  450  of the second receiving container  400 .  
         [0047]    The second receiving container  400  further includes a reflecting member  415  for increasing an inclining efficiency of the external light on the first side surface  110  of the light guide plate  100 . The reflecting member  415  is disposed on the lighting sidewall  410  to face the first side surface  110  of the light guide plate  100 .  
         [0048]    Embodiment 2  
         [0049]    [0049]FIG. 3 is an exploded perspective view showing a backlight assembly according to a second embodiment of the present invention.  
         [0050]    A backlight assembly  900  comprises a light guide plate  100 , lamp  340 , first receiving container  300  and second receiving container  400 . The backlight assembly  900  provides the external light and artificial light to the LCD panel to display the image. In preferred embodiments of the present invention, the backlight assembly  900  further comprises an optical sheet  200  and a reflecting plate  500  in order to display high quality image.  
         [0051]    The optical sheet  200  comprises a diffusion sheet  240  and a prism sheet  250 . The diffusion sheet  240  is disposed on the light emitting surface  160  of the light guide plate  100  to uniformly maintain brightness of the light emitted from the light emitting surface  160 . The prism sheet  250  is disposed on the diffusion sheet  240  to control a direction and a visual angle of the light emitted from the diffusion sheet  240 . The reflecting plate  500  is disposed under the light guide plate  100  to reflect the light leaked from the light reflecting surface  150  to the light guide plate  100 .  
         [0052]    The diffusion sheet  240  is provided with a plurality of third fixing protrusions  242  partially extended from end portions thereof. The prism sheet  250  is provided with a plurality of fourth fixing protrusions  252  partially extended from end portions thereof. The third and fourth fixing protrusions  242  and  252  are received in the first and second fixing recesses  352   b  and  356   b  of the first receiving container  300 , respectively, when the diffusion and prism sheets  240  and  250  are received in the first receiving container  300 .  
         [0053]    The backlight assembly  900  receives the external light through the lighting sidewall  410  of the second receiving container  400  and the first side surface  110  of the light guide plate  100  and receives the artificial light emitted from the lamp  340  through the second side surface  120  of the light guide plate  100 . The external light and artificial light are reflected from the light reflecting surface  150  of the light guide plate  100  and emitted through the light emitting surface  160  of the light guide plate  100 .  
         [0054]    Embodiment 3  
         [0055]    [0055]FIG. 4 is a perspective view showing a light guide plate according to a third embodiment of the present invention. FIG. 5 is a cross-sectional view taken along the line V-V for showing the light guide plate shown in FIG. 4.  
         [0056]    A light guide plate  150  further includes an external light-lighting body  160  disposed on a first side surface  152  of the light guide plate  150 .  
         [0057]    The external light-lighting body  160  includes a first light reflecting surface  162 , a second light reflecting surface  164 , and a lighting surface  165 .  
         [0058]    The first light reflecting surface  162  is extended from a first edge portion  152   a  where a light emitting surface  154  of the light guide plate  150  comes in contact with the first side surface  152  thereof toward an upper portion of the light emitting surface  154 . The first light reflecting surface  162  is perpendicular to the light emitting surface  154  and parallel to the first side surface  152 . The second light reflecting surface  164  is extended from a second edge portion  153   a  where a light reflecting surface  153  of the light guide plate  150  comes in contact with the first side surface  152  thereof. The second light reflecting surface  164  is inclined to the first side surface  110  at an angle of β. For instance, the second light reflecting surface  164  is inclined parallel to the lighting sidewall  410  of the second receiving container  400 . The lighting surface  165  connects between the first and second light reflecting surfaces  162  and  163 .  
         [0059]    The first light reflecting surface  162  reflects an external light (that is not inclined on the second light reflecting surface  164 ) to the second reflecting surface  164  so as to increase an amount of the external light supplied to the light guide plate  150 .  
         [0060]    The external light-lighting body  160  may further includes a first light reflecting sheet  162   a  disposed on the first light reflecting surface  162  to reduce an amount of the external light leaked from the first light reflecting surface  162 . Further, the external light-lighting body  160  may further includes a second light reflecting sheet  163   a  disposed on the second light reflecting surface  164  to reduce an amount of the external light leaked from the second light reflecting surface  164 .  
         [0061]    Embodiment 4  
         [0062]    [0062]FIG. 6 is an exploded perspective view showing a backlight assembly according to a fourth embodiment of the present invention.  
         [0063]    Referring to FIG. 6, a backlight assembly  900  further includes a light reflecting sheet  480  disposed over the lighting sidewall  410  and bottom surface  450  of the second receiving container  400 . Advantageously, a number of steps for assembling the backlight assembly  900  may be reduced by disposing the light reflecting sheet  480  on the lighting sidewall  410  and bottom surface  450 . Further, a reflecting plate (for example, the reflecting plate  500  of FIG. 3) may be removed in the embodiment, a number of parts of the backlight assembly  900  may be reduced, thereby reducing an entire thickness of the backlight assembly  900 .  
         [0064]    Embodiment 5  
         [0065]    [0065]FIG. 7 is an exploded perspective view showing an LCD apparatus according to a fifth embodiment of the present invention. FIG. 8 is a cross-sectional view showing the LCD panel assembly shown in FIG. 7.  
         [0066]    An LCD apparatus  1000  comprises a backlight assembly  900 , an LCD panel assembly  950  received in the backlight assembly  900 , a chassis  960  and a lower case  970  for combining the backlight assembly  900  to the LCD panel assembly  950 .  
         [0067]    The LCD panel assembly  950  comprises a reflective LCD panel assembly, a transmissive LCD panel assembly or a transreflective LCD panel assembly. In a preferred embodiment of the present invention, the transmissive LCD panel assembly is employed as the LCD panel assembly  950 .  
         [0068]    The transmissive LCD panel assembly  950  comprises a TFT (thin film transistor) substrate  951 , a liquid crystal  952 , and a color filter substrate  953 .  
         [0069]    The TFT substrate  951  comprises a transparent glass substrate. For example, the TFT substrate  951  comprises a plurality of TFTs  951   a  disposed on the substrate  951  in a matrix configuration, a pixel electrode  951   b  for receiving a power voltage from the TFTs  951   a , and a first alignment layer  951   c.    
         [0070]    The color filter substrate  953  faces the TFT substrate  951 . The color filter substrate  953  comprises a color filter  953   a  disposed on a transparent glass substrate, a common electrode  953   b  entirely disposed on the transparent glass substrate to cover the color filter  953   a,  and a second alignment layer  953   c.  The color filter  953   a  faces the pixel electrode  951   b  of the TFT substrate  951 .  
         [0071]    The liquid crystal  952  is interposed between the TFT substrate  951  and color filter substrate  953 . In order to interpose the liquid crystal  952  between the TFT substrate  951  and color filter substrate  953 , the TFT substrate  951  is separated from the color filter substrate  953  in a predetermined distance. A spacer (not shown) and a sealant (not shown) may be formed between the TFT substrate  951  and color filter substrate  953  is maintained the predetermined distance.  
         [0072]    The transmissive LCD panel assembly  950  is received in the first receiving container  300  of the backlight assembly  900 . The transmissive LCD panel assembly  950  is disposed on the first and second steps  352   c  and  356   c  of the first receiving container  300 . The reflecting plate  500 , light guide plate  100  and optical sheet  200  are disposed under the transmissive LCD panel assembly  950 .  
         [0073]    The chassis  960  comprises a first surface  961  having a rectangular frame shape to expose an effective display area of the transmissive LCD panel assembly  950  and a second surface  962  extended from an edge of the first surface  961  and perpendicular to the first surface  961 . The second surface  962  of the chassis  960  is outwardly combined to the fourth to sixth sidewalls  420 ,  430  and  440  of the second receiving container  400 .  
         [0074]    The first receiving container  300  prevents the transmissive LCD panel assembly  950  from being moved in a horizontal direction. The chassis  960  prevents the transmissive LCD panel assembly  950  from being moved in a vertical direction. Also, the chassis  960  may prevent an edge portion of the transmissive LCD panel assembly  950  from being damaged and remove a static electricity of the transmissive LCD panel assembly  950 .  
         [0075]    [0075]FIG. 9 is a cross-sectional view showing the LCD apparatus shown in FIG. 7.  
         [0076]    Referring to FIG. 9, the first surface  961  of the chassis  960  is provided with an external light-inducting window  961   a  for inducting the external light into the lighting sidewall  410  of the second receiving container  400  of the backlight assembly  900 . The external light is supplied to the lighting sidewall  410  and first side surface  110  of the light guide plate  100  through the external light-inducting window  961   a.  Also, the chassis  960  further comprises a sheet  963  disposed on the external light-inducting window  961   a  so as to intercept a foreign substance flowed in the LCD apparatus  1000  through the external light-inducting window  961   a.    
         [0077]    Embodiment 6  
         [0078]    FIGS.  10  to  12  are schematic views showing an LCD apparatus according to a sixth embodiment of the present invention.  
         [0079]    According to a preferred embodiment of the present invention, a foreign substance (which enters the LCD apparatus  1000  through the external light-inducting window  961   a ) can be intercepted by partially transforming a shape of the external light-lighting body  160  shown in FIG. 4). The external light-lighting body  160  is provided with a sealing protrusion  166  disposed on the lighting surface  165 . The sealing protrusion  166  is formed by partially protruding the upper surface of the lighting surface  165 .  
         [0080]    The sealing protrusion  166  has a size identical to that of the external light-inducting window  961   a  and is inserted into the external light-inducting window  961   a.  Thus, the LCD apparatus  1000  can prevent the foreign substance from being flowed into the LCD apparatus  1000 .  
         [0081]    Advantageously, the backlight assembly and LCD apparatus according to preferred embodiments of the present invention simultaneously supply an external and artificial light (e.g., a lamp light) to the LCD panel assembly. Thus, the LCD apparatus increases brightness of the light and reduces the number of parts and power consumption.  
         [0082]    Although the LCD panel assembly according to preferred embodiments of the present invention comprises the transmissive LCD apparatus, the reflective and transreflective LCD panel assemblies can be applied to the LCD panel assembly of the present invention. For example, a reflective LCD apparatus according to a preferred embodiment of the present invention may have a light guide plate disposed on a reflective LCD panel assembly for receiving an external light and artificial light.  
         [0083]    Although the exemplary embodiments of the present invention have been described, it is understood that the present invention should not be limited to these exemplary embodiments but various changes and modifications can be made by one ordinary skilled in the art within the spirit and scope of the present invention as hereinafter claimed.