Abstract:
A liquid crystal panel assembly is provided, which includes a liquid crystal panel displaying an image, a light source unit arranged on a side of the liquid crystal panel, an optical sheet unit arranged in the rear of the liquid crystal panel, a reflection sheet arranged to be spaced apart from the optical sheet unit, a light scattering unit arranged adjacent to the light source unit, where the light scattering unit scatters light such that at least some of the light emitted from the light source unit is incident toward the reflection sheet, and a pattern member arranged on the reflection sheet, the pattern member including a pattern of repeating optical shapes.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority under 35 U.S.C. §119(a) to Korean Patent Application No. 10-2011-0116360, filed on Nov. 9, 2011, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    Apparatuses consistent with exemplary embodiments relate to a liquid crystal panel assembly and an image display apparatus having the same, and more particularly to an LGP-less liquid crystal panel assembly and an image display apparatus having the same. 
         [0004]    2. Description of the Related Art 
         [0005]    A liquid crystal display apparatus that is one type of image display apparatus is an apparatus that implements an image using liquid crystals and is applied to various kinds of display devices such as televisions and computer monitors. 
         [0006]    Such a liquid crystal display apparatus includes a liquid crystal panel assembly, and this liquid crystal panel assembly includes a light source unit and a liquid crystal panel. The light source unit is arranged in the rear or on a side of the liquid crystal panel. In the case where the light source unit is arranged on the side of the liquid crystal panel, a light guide panel (LGP) is typically provided in the rear of the liquid crystal panel so that the liquid crystal panel uniformly provides light generated from the light source unit over the whole region of the liquid crystal panel. 
         [0007]    Recently, to save costs and make a lighter weight device, a liquid crystal panel assembly with no LGP, which is called an LGP-less liquid crystal panel assembly, has been developed. In the case of the LGP-less liquid crystal panel assembly, a light scattering unit, such as an optical lens or a reflection mirror, is arranged around the light source unit so that the light can be uniformly spread over a reflection sheet that is arranged in the rear of the liquid crystal panel. 
         [0008]    An image that is provided by such an LGP-less liquid crystal panel assembly in a region that is adjacent to the light source unit may appear much brighter than an image in other regions. This phenomenon may entirely deteriorate the uniformity of luminance to cause the deterioration of picture quality. 
       SUMMARY 
       [0009]    One or more exemplary embodiments may address at least the above problems and/or disadvantages and provide at least the advantages described below. Accordingly, one or more exemplary embodiments may provide a liquid crystal panel assembly and an image display apparatus having the same, which can improve the luminance uniformity of an image. 
         [0010]    According to an aspect of an exemplary embodiment an LGP-less liquid crystal panel assembly is provided which includes a liquid crystal panel which displays an image; a light source unit disposed at a side of the liquid crystal panel; an optical sheet unit disposed at a rear of the liquid crystal panel; a reflection sheet disposed at a rear of the optical sheet unit and spaced from the optical sheet unit; a light scattering unit disposed adjacent to the light source unit, wherein the light scattering unit scatters light such that at least some of the light emitted form the light source unit is incident toward the reflection sheet; and a pattern member disposed on a front of the reflection sheet, the pattern member comprising a patter of repeating optical shapes. 
         [0011]    The optical shapes of the pattern member each extend along a length direction of the liquid crystal panel assembly and are repeatedly arranged along a width direction of the liquid crystal panel assembly. 
         [0012]    Each of the optical shapes have a triangular cross section. 
         [0013]    Each of the optical shapes may have a cross section in a half convex lens shape. 
         [0014]    The pattern member may include a base portion which overlaps the reflection sheet, and the optical shapes may project from the base portion. 
         [0015]    The pattern member may be transparent. 
         [0016]    The pattern member may be made of polycarbonate or polymethyl methacrylate. 
         [0017]    The pattern member and the reflection sheet may be bonded together. 
         [0018]    The light scattering unit may include at least one reflection minor surrounding the light source unit. 
         [0019]    The light scattering unit may include an upper reflection minor arranged on an upper side of the light source unit and a lower reflection mirror arranged on a lower side of the light source. 
         [0020]    The liquid crystal panel assembly may further include an upper chassis and a lower chassis which accommodate therebetween the liquid crystal panel, the light source unit, the reflection sheet, and the light scattering unit, wherein the reflection sheet is supported by the lower chassis. 
         [0021]    The optical sheet unit may include a prism sheet. 
         [0022]    The light source unit may include a plurality of LED light sources. 
         [0023]    According to an aspect of another exemplary embodiment an image display apparatus is provided including the above-described liquid crystal panel assembly. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The above and other exemplary aspects, features and advantages will be more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: 
           [0025]      FIG. 1  is a partial cross-sectional view illustrating a liquid crystal panel assembly according to an exemplary embodiment of the present disclosure; 
           [0026]      FIG. 2  is a photograph showing an example of a typical liquid crystal panel assembly in which an edge region of an image has high luminance; 
           [0027]      FIG. 3  is a partial cross-sectional view of a pattern member provided in the liquid crystal panel assembly of  FIG. 1 ; 
           [0028]      FIG. 4  is a partial cross-sectional view illustrating an alternative embodiment of the pattern member illustrated in  FIG. 3 ; and 
           [0029]      FIG. 5  is a cross-sectional view schematically illustrating an example of an image display apparatus according to an exemplary embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0030]    Hereinafter, exemplary embodiments are described in detail with reference to the accompanying drawings. 
         [0031]      FIG. 1  is a partial cross-sectional view illustrating a liquid crystal panel assembly according to an exemplary embodiment of the present disclosure.  FIG. 2  is a photograph showing an example of a typical liquid crystal panel assembly in which an edge region of an image has high luminance.  FIG. 3  is a partial cross-sectional view of a pattern member provided in the liquid crystal panel assembly of  FIG. 1 , and  FIG. 4  is a partial cross-sectional view illustrating an alternative embodiment of the pattern member illustrated in  FIG. 3 . 
         [0032]    Referring to  FIG. 1 , a liquid crystal panel assembly  100  according to an exemplary embodiment of the present disclosure includes an upper chassis  110 , a lower chassis  120 , and an intermediate chassis  130 . 
         [0033]    The upper chassis  110  and the lower chassis  120  are coupled to each other by a fastening member such as a screw (not illustrated), and form a space that accommodates components in the liquid crystal panel assembly  100 . The lower chassis  120  includes a bottom portion  121  and a side portion  122  which are perpendicular to each other. The intermediate chassis  120  is also called a middle mold, and supports the internal components of the liquid crystal panel assembly  100  together with the upper and lower chasses  110  and  120 . For this, the intermediate chassis  130  is arranged at an edge region of the liquid crystal panel assembly  100 , and arranged between the upper chassis  110  and the lower chassis  120 . 
         [0034]    Referring to  FIG. 1 , the liquid crystal panel assembly  100  includes a liquid crystal panel  140 , an optical sheet unit  145 , a light source unit  150 , a light scattering unit  160 , a reflection sheet  170 , and a pattern member  180 . 
         [0035]    The liquid crystal panel  140  displays a color image using light provided from the light source unit  150 . The liquid crystal panel  140  includes a color filter substrate (not illustrated) having a color filter layer and a thin film transistor substrate (not illustrated) having thin film transistors, and liquid crystals (not illustrated) are accommodated between the color filter substrate and the thin film transistor substrate. Since the liquid crystal panel  140  is well known in the art, the detailed description thereof will be omitted. 
         [0036]    The optical sheet unit  145  is arranged in parallel to the liquid crystal panel  140  in the rear of the liquid crystal panel  140 . Although the optical sheet unit  145  is illustrated as if it is a single member in  FIG. 1 , it may include a plurality of optical sheets such as a diffusion sheet, a prism sheet, and the like. 
         [0037]    The light source unit  150  is arranged at an edge region of the liquid crystal panel assembly  100 . Although the light source unit  150  is shown as if it is a single member in  FIG. 1 , it may include a plurality of light sources arranged in a width direction (that is, a Y direction) of the liquid crystal panel assembly  100 . These light sources are mounted on a driving substrate  151 , and this driving substrate  151  is fixed to a side portion  122  of the lower chassis  120 . In this embodiment, the light sources are LEDs, and in another alternative embodiment, another type of light sources may be adopted. 
         [0038]    The light scattering unit  160  is arranged adjacent to the light source unit  150 , and widely spreads the light generated from the light source unit  150  onto the reflection sheet  170 . That is, the light irradiated by the light source unit  150  may be guided toward the reflection sheet  170  by the optical scattering unit  160 . As described above, the light scattering unit  160  serves to widely disperse or direct the light over the whole region of the reflection sheet  170 , and thus it may be called a “directing unit”. 
         [0039]    The light scattering unit  160  may include at least one reflection mirror that surrounds the light source unit  150 . In this embodiment, the light scattering unit  160  includes a pair of reflection minors, that is, an upper reflection mirror  161  and a lower reflection minor  162 . An upper reflection surface  161   a , which is a curved surface, is provided inside the upper reflection mirror  161 , and a lower reflection surface  162   a , which is symmetrical with the upper reflection surface  161   a , is provided inside the lower reflection mirror  162 . Here, the upper reflection surface  161   a  and the lower reflection surface  162   a  are designed to be in a curved shape to uniformly spread the light from the respective light source units  150  onto the reflection sheet  170 . 
         [0040]    As illustrated in  FIG. 1 , the liquid crystal panel assembly  100  is provided with no light guide panel, and the function of such a light guide panel may be replaced by the light scattering unit  160 . Since the liquid crystal panel assembly  100  is provided with no light guide panel in this embodiment, the cost saving and light weight can be achieved. 
         [0041]    Although the light scattering unit  160  includes reflection mirrors surrounding the light source unit  150  in this embodiment, the light scattering unit  160  may alternately include an optical lens that is arranged in front of the optical unit  150  to refract the light from the light source unit  150  at various angles. 
         [0042]    The reflection sheet  170  is a rectangular sheet that is arranged on a bottom portion  121  of the lower chassis  120  to face the optical sheet unit  145 . The reflection sheet  170  is extended along the length direction (X direction) and the width direction (Y direction) of the liquid crystal panel assembly  100 . That is, the reflection sheet  170  is extended along the X-Y plane in  FIG. 1 . 
         [0043]    The reflection sheet  170  reflects the light generated from the light source unit  150  toward the optical sheet unit  145 . That is, the light irradiated by the light source unit  150  reaches the reflection sheet  170  directly or through the light scattering unit  160 , and the light that has reached the reflection sheet  170  is reflected by the reflection sheet  170  toward the optical sheet unit  145 . 
         [0044]    The reflection sheet  170  is made of polyethylene terephthalate (PET). However, in another alternative embodiment, the reflection sheet  170  may be made of silver. Silver is relatively expensive, and thus the reflection sheet  170  may be made of PET. 
         [0045]    As can be seen from  FIG. 1 , an incident angle θ 1  of the light that is incident from the light source unit  150  onto the reflection sheet  170  and an incident angle θ 2  of the light that is incident from the optical scattering unit  160  onto the reflection sheet  170  become greater in a region that is nearer to the light source unit  150 . That is, the incident angles θ 1  and θ 2  become greatest at an edge region (that is, regions adjacent to the light source) of the reflection sheet  170 . 
         [0046]    As the incident angle of the light is larger, the reflection angle of the light also becomes larger. Accordingly, the incident angle of the light, which is reflected from the edge region of the reflection sheet  170  and is incident to the edge region of the optical sheet unit  145 , also becomes larger. As described above, the optical sheet unit  145  includes a prism sheet. This prism sheet has the characteristics that it transmits light having an incident angle that is larger than a reference angle and fully reflects light having an incident angle that is smaller than the reference angle. Accordingly, the light that is incident from the reflection sheet  170  to the edge region of the optical sheet unit  145  has a large incident angle, and thus a considerable portion of the light penetrates toward the liquid crystal panel  140 . Accordingly, a larger amount of light can be provided in a region adjacent to the light source unit  150  of the liquid crystal panel in comparison to other regions, 
         [0047]    In this case, an image which is generated by the liquid crystal panel assembly  100  in a region that is adjacent to the light source unit  150  may appear much brighter than an image in other regions.  FIG. 2  shows an example of a typical LGP-less liquid crystal panel assembly having such problems. In  FIG. 2 , an edge region E of an image I appears much brighter than the remaining region. This phenomenon may deteriorate the uniformity of luminance to cause the deterioration of picture quality. 
         [0048]    The above-described problems may be solved by increasing an optical distance between the light source unit  150  and the reflection sheet  170  through designing the reflection sheet  170  with a larger thickness. However, this scheme goes against the slim design of the liquid crystal panel assembly  100 , and thus it is difficult to adopt this scheme in the liquid crystal panel assembly  100 . 
         [0049]    The pattern member  180  is provided to solve the above-described problems of luminance uniformity deterioration. Referring to  FIG. 1 , the pattern member  180  is arranged on the reflection sheet  170 , and is substantially in a rectangular sheet shape. In the same manner as the reflection sheet  170 , the pattern member  180  is extended along the length direction (X direction) or the width direction (Y direction) of the liquid crystal panel assembly  100 . That is, the reflection sheet  180  is extended along the X-Y plane in  FIG. 1 . 
         [0050]    The pattern member  180  has a transparent material. In this embodiment, the pattern member  180  is made of polycarbonate or polymethyl methacrylate (PMMA). 
         [0051]    Referring to  FIG. 3 , the pattern member  180  includes a base portion  181  and a plurality of patterns  182 . 
         [0052]    The base portion  181  is arranged to overlap the reflection sheet  170 . The base portion  181  may be seated on the reflection sheet  170  without adhesives or may be attached to the reflection sheet  170  by adhesives. 
         [0053]    Patterns  182  having the same shape are repeatedly formed along the width direction (Y direction). The respective patterns  182  project from the base portion  181 , and are uniformly extended along the length direction (X direction) of the liquid crystal panel assembly  100 . 
         [0054]    As illustrated, as seen from the X direction, each pattern  182  may have a triangular cross section. That is, the cross section of the pattern  182  in the Y-Z plane is a triangle. However, the shape of the pattern  182  is not limited thereto, and may have other cross-sectional shapes. For example, the pattern  182  may have other polygonal cross sections, such as a quadrangle, a pentagon, a hexagon, and the like, or may have a cross section of a curved surface. An example of the pattern member  180  having patterns  182  with a cross section of a curved surface is illustrated in  FIG. 4 . As illustrated in  FIG. 4 , each pattern  182  may have a cross section in a convex lens shape. 
         [0055]    The light that propagates from the light source unit  150  or the light scattering unit  160  to the reflection sheet  170  first reaches the pattern member  180 , and the pattern member  180  serves to transmit a portion of the light toward the reflection sheet  170  and to reflect the remaining portion of the light. That is, the pattern member  180  performs a similar function to a prism. 
         [0056]    The light that is irradiated from the light source unit  150 , through the use of the pattern member  180 , can propagate more uniformly toward the reflection sheet  170 . Further, since the light is refracted by the patterns  182  of the pattern member  180  before reaching the reflection sheet  170 , the incident angles θ 1  and θ 2  (see  FIG. 1 ) of the light that is incident to the region of the reflection sheet  180  adjacent to the light source unit  150  may be reduced. 
         [0057]    As a result, a phenomenon that an image appears excessively bright in the edge region (that is, regions adjacent to the light source) of the liquid crystal panel assembly  100  can be prevented. That is, the problems of luminance uniformity deterioration as shown in  FIG. 2  can be solved. 
         [0058]    Further, since the pattern member  180  is in a sheet shape having a thin thickness, the whole thickness of the liquid crystal panel assembly  100  is not significantly increased. Accordingly, the scheme for improving the luminance uniformity through the pattern member  180  is in accordance with the slim design of the liquid crystal panel assembly  100 . 
         [0059]      FIG. 5  is a cross-sectional view schematically illustrating an image display apparatus according to an exemplary embodiment of the present disclosure. 
         [0060]    The image display apparatus  1  of  FIG. 5  exemplifies a liquid crystal display television (LCD TV). However, it will be apparent to those of skilled in the art that the present disclosure can be adopted in other types of display apparatuses such as a computer monitor. 
         [0061]    The image display apparatus  1  includes an upper housing  10  and a lower housing  20 . These housings  10  and  20  accommodate the liquid crystal panel assembly  100 , according to the above-described embodiments, therein. As described above, the light source unit  150  of the liquid crystal panel assembly  100  includes a plurality of LED light sources. From this viewpoint, the image display apparatus  1  of  FIG. 5  may be called an LED TV. 
         [0062]    In the rear of the liquid crystal panel assembly  100 , a power board  30  supplying the power to the image display apparatus  1  and a control board  40  controlling the operation of the liquid crystal display apparatus  1  are arranged. Although the power board  30  and the control board  40  are simply illustrated in  FIG. 5 , other circuit boards can be additionally provided in the image display apparatus  1 . 
         [0063]    As described above, the pattern member  180  for improving the luminance uniformity is provided in the liquid crystal panel assembly  100 , and thus the image display apparatus  1  of  FIG. 5  that is provided with the liquid crystal panel assembly  100  can provide an image with improved luminance uniformity. 
         [0064]    While the present disclosure has been shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the inventive concept, as defined by the appended claims.