Patent Publication Number: US-2010118226-A1

Title: Liquid crystal display device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 U.S.C. 119 to Korean Patent Application No. 10-2008-00112416, filed on Nov. 12, 2008, which is hereby incorporated by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a liquid crystal display (LCD) device and, more particularly, to an LCD device in which a lower cover extends to effectively absorb an impact applied from the exterior, thus being resistant to an external impact. 
     2. Description of the Related Art 
     In general, an LCD includes a liquid crystal display panel including a thin film transistor (TFT) array substrate, a color filter substrate which are attached with a certain gap in a facing manner, and a liquid crystal layer provided in the space between the TFT array substrate and the color filter substrate, a driving unit for driving the liquid crystal display panel, and a backlight unit for providing light to the liquid crystal display panel. 
     The TFT array substrate includes a plurality of data lines arranged to be separated in a vertical direction and a plurality of gate lines arranged to be separated in a horizontal direction. The plurality of data lines and the plurality of gate lines cross to define pixels. The pixels defined at each crossing of the data lines and the gate lines are arranged in a matrix form. 
     On the color filter substrate, there are formed red, green and blue color filter layers at positions corresponding to the pixels, and black matrixes formed between the color filter layers to prevent light leakage between the color filter layers and prevent a color interference of light that passes through the pixels. 
     A common electrode and pixel electrodes are formed on inner facing surfaces of the color filter substrate and the TFT array substrate, respectively, to apply an electric field to the liquid crystal layer. In this case, the pixel electrodes are formed at each pixel on the TFT array substrate, while the common electrode is integrally formed on the entire surface of the color filter substrate. The voltage applied to the pixel electrode is controlled in a state that voltage is applied to the common electrode to change the alignment of liquid crystal molecules of the liquid crystal layer, thus individually adjust light transmittance of the pixels. 
     The backlight unit supplies light to the LCD device that does not emit light by itself, and the light transmittance is determined by the alignment of the liquid crystals when light emitted from the backlight unit passes through the liquid crystal layer, to display an image. 
       FIG. 1  is an exploded perspective view schematically showing the structure of the general LCD device, and  FIG. 2  is a sectional view of the general LCD device. As shown in  FIGS. 1 and 2 , the LCD device includes a liquid crystal display panel  10  including a first substrate  1 , a second substrate  3  and a liquid crystal layer (not shown) interposed between the first and second substrates  1  and  3 , and displaying an image when a signal is applied from the exterior thereto, a light guide plate  20  disposed below the liquid crystal display panel  10  and guide light emitted from a light source (not shown) such as a light emitting diode (LED) or a lamp so as to be supplied to the liquid crystal display panel  10 , an optical sheet  30  provided between the liquid crystal display panel  10  and the light guide plate  20  to diffuse and condense light supplied to the liquid crystal display panel after being guided from the light guide plate  20  to thus improve light efficiency, a main support unit  25  disposed under the light guide plate  20  to support the light guide plate  20  and the liquid crystal display panel  10 , and a lower cover  40  positioned under the main support unit  25 , to which the liquid crystal display panel  10 , the light guide plate  20 , the optical sheet  30 , and the main support unit  25  are assembled. 
     In addition, a reflector  28  is formed on the lower cover  40  to reflect light made incident to the lower cover  40  to the liquid crystal display panel  10  to improve light efficiency. 
     Although not shown, a plurality of pixels are provided on the first substrate  1  of the liquid crystal display panel  10 . Each pixel includes pixel electrodes and a TFT, and a common electrode is formed on the second substrate  3 . When an external signal is applied through the TFT, an electric field is formed in the liquid crystal layer to adjust alignment of liquid crystal molecules to adjust the transmittance of light that passes through the liquid crystal layer to thus display an image. In this case, the first and second substrates  1  and  3  includes polarizers  8  and  9  attached thereon to control a polarization direction of light made incident to the liquid crystal layer and light outputted from the liquid crystal layer. 
     Edges of the liquid crystal display panel  10  are supportedly placed on the main support unit  25 . A pad  36  is formed on the main support unit  25 , and the liquid crystal display panel  10  is positioned on the pad  36 . 
     In the LCD device configured as described above, the liquid crystal display panel may be damaged by an impact applied thereto. Namely, when an external force is applied, it is transferred to the liquid crystal display panel to damage it. In particular, the thickness of the substrate made of glass tends to be reduced in line with the trend that the LCD is becoming lighter, so the strength of the liquid crystal display panel is degraded, and accordingly, it may be damaged even by a weak external force applied thereto. 
     SUMMARY OF THE INVENTION 
     Therefore, in order to address the above matters, the various features described herein have been conceived. 
     An aspect of the present invention provides a liquid crystal display (LCD) device capable of preventing damage to a liquid crystal display panel by effectively absorbing an impact applied from the exterior. 
     According to an aspect of the present invention, there is provided an LCD device including: a liquid crystal display panel; a light source provided below the liquid crystal display panel and emitting light to supply the light to the liquid crystal display panel; a light guide plate below the liquid crystal display panel to guide the light emitted from the light source to the liquid crystal display panel; a lower cover for receiving and assembling the liquid crystal display panel, the light source and the light guide plate; and a bent portion extending from an end portion of the lower cover and bent toward an outer side of the liquid crystal display panel at least once to absorb an impact applied from the exterior. 
     The bent portion may be bent three or four times in a quadrangular shape, or may be bent in a circular shape or an ellipse shape. 
     In an exemplary embodiment of the present invention, because the lower cover includes the bent portion formed by bending an end portion of the lower cover at least once to the outer side to effectively absorb an impact applied from the exterior, the LCD can be prevented from being damaged by the external impact. 
     The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing the structure of the related art liquid crystal display (LCD) device; 
         FIG. 2  is a sectional view showing the structure of the related art LCD device; 
         FIG. 3  is a sectional view showing the structure of an LCD according to one exemplary embodiment of the present invention; 
         FIG. 4  is a plan view showing the structure of a liquid crystal display panel of the LCD according to an exemplary embodiment of the present invention; and 
         FIG. 5  is a sectional view showing the structure of an LCD device according to another exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 3  is a sectional view showing the structure of a liquid crystal display (LCD) device according to one exemplary embodiment of the present invention. 
     As shown in  FIG. 3 , the LCD device according to an exemplary embodiment includes: a liquid crystal display panel  110 , a light guide plate  120  disposed below the liquid crystal display panel  110  and guide light emitted from a light source (not shown) such as a light emitting diode (LED) or a lamp so as to be supplied to the liquid crystal display panel  110 , an optical sheet  130  provided between the liquid crystal display panel  110  and the light guide plate  120  to diffuse and condense light supplied to the liquid crystal display panel after being guided from the light guide plate  120  to thus improve light efficiency, a main support unit  125  disposed under the light guide plate  120  to support the light guide plate  120  and the liquid crystal display panel  110 , and a lower cover  140  allowing the liquid crystal display panel  110 , the light guide plate  120 , the optical sheet  130 , and the main support unit  125  to be accommodated and assembled therein. 
     An end portion of the lower cover  140  extends to form a bent portion  140   a  bent to an outer side of the liquid crystal display panel  110 . The bent portion  140   a  is bent at least once, and preferably, three or four times to the outer side of the liquid crystal display panel  110 . In  FIG. 3 , the bent portion  140   a  is bent with a length similar to the length of the lower cover  140  at the side of the LCD device, but the bent length of the portion  140   a  may be smaller than the length of the side of the lower cover  140 . 
     Accordingly, as the lower cover  140  extends to form the bent portion  140 , a transfer of an eternal impact, which has been applied to the LCD, to the liquid crystal display panel  110  can be interrupted. Namely, because the external impact is absorbed by the bent portion  140 , the liquid crystal display panel  110  can be prevented from being damaged by the external impact. 
     The liquid crystal display panel  110  includes an image display part  113  in which a plurality of gate lines  105  and a plurality of data lines  106  cross horizontally and vertically to define a plurality of pixels arranged in a matrix form, and a gate pad part  114  connected with the gate lines  105  of the image display part  113 , and a data pad part  115  connected with the data lines  106 . The gate pad part  114  and the data pad part  115  are formed at the edges of the first substrate  101  not overlapping with the second substrate  103  on which color filters (not shown) are formed. The gate pad part  114  supplies scan signals supplied from a gate driver integrated circuit (IC) to the gate lines of the image display part  113 , and the data pad part  115  supplies image information supplied from a data driver IC to the data lines of the image display part  113 . 
     Although not shown, the first substrate  101  of the image display part  113  includes a thin film transistor (TFT) is formed at each crossing of the data lines  106  to which the image signal is applied and the gate lines  105  to which the scan signal is applied, a pixel electrode connected with the TFT to drive liquid crystal molecules of the liquid crystal layer, and a protection layer formed on the entire surface of the first substrate  101  to protect the electrode and the TFTs. 
     The second substrate  103  of the image display part  113  includes color filters coated at each pixel area by being divided by black matrixes and a transparent common electrode formed on the first substrate  101 . 
     As described above, a certain cell gap is maintained between the first and second substrates  101  and  103 , and the first and second substrates  101  and  103  are attached by a sealing part (not shown) formed at the edges of the image display part  113 . A liquid crystal layer (not shown) is formed at a space between the first and second substrates  101  and  103 . 
     The light guide plate  120  is disposed on a reflector  128  formed on the lower cover  140  to guide light made incident from the light source toward the liquid crystal display panel  110 , and light made incident from the bottom surface of the lower cover  140  is reflected by the reflector  128  and then supplied to the liquid crystal display panel  110  through the light guide plate  120 . 
     Although not shown, an LED or a fluorescent lamp is used as the light source. When the LED is used, a plurality of LEDs may be disposed along one side of the light guide plate  120  such that they face the side of the light guide plate  120 , so light is made incident through the side of the light guide plate  120 . In addition, when a fluorescent lamp is used, it may be disposed at one side or at both sides of the light guide late  128  to provide light to the liquid crystal display panel  110  through the light guide plate  120 . In this case, a lamp housing may be formed at the main support unit  125  at the side of the light guide plate  120  to accommodate the lamp. 
     Although not shown, the optical sheet  130  includes a diffusion sheet for diffusing light made incident from the light guide plate  120 , a prism sheet for making the diffused light to proceed to the front side, and a protection sheet for protecting the diffusion sheet and the prism sheet, to thereby constantly provide uniform light to the liquid crystal display panel  110 . 
     The main support unit  125  fixedly supports the liquid crystal display panel  110 , the light guide plate  120 , and the optical sheet  130 . As illustrated the main support unit  125  is formed to the outer surface of the liquid crystal display panel  110  and the side of the liquid crystal display panel  110  is in contact with the main support unit  125 , but the main support unit  125  may be formed only at the lower portion of the liquid crystal display panel  110  and the side of the liquid crystal display panel  100  may be directly in contact with the lower cover  140 . 
     As illustrated, the liquid crystal display panel  110  is placed on the pad  126  formed on the upper surface of the main support unit  125 , and the light guide plate  120  and the optical sheet  130  are placed on the lower cover  140 . However, the optical sheet  130  may be placed on the main support unit  125 . In this case, the optical sheet  130  and the liquid crystal display panel  110  may be spaced apart from each other. 
     As described above, in the present invention, the lower cover  140  extends to be bent to the outer side of the LCD device to form the bent portion  140   a  to thereby prevent the liquid crystal display panel  110  from being damaged by an external impact. In this case, the bent portion  140   a  may be bent to the inner side of the LCD device, namely, toward the side where the liquid crystal display panel  110 , but preferably, the bent portion  140   a  is bent to the outer side for the following reasons. 
     That is, if the lower cover  140  is bent to the inner side, the length of the bent portion  140   a  is limited. Namely, if the bent portion  140   a  is so lengthy as to be in contact with the inner bottom surface of the lower cover  140 , the lower cover  140  may be damaged or a foreign material or debris may be generated. Thus, if the lower cover  140  is inwardly bent, the length of the bent portion  140   a  would be shortened to fail to perfectly absorb an external impact. 
     In addition, if the lower cover  140  is bent inwardly, it is not possible to bend the lower cover  140  as many times as possible. The inner side of the lower cover  140  is a space in which the liquid crystal display panel  110  and various components are accommodated. Thus, if the lower cover  140  is inwardly bent, the internal space of the lower cover  140  should be extended as wide as the number of bending times of the lower cover  140 , resulting in an increase in the size of the LCD device. In addition, it is more difficult to inwardly bend the lower cover  140  than to outwardly bend the lower cover  140 . Thus, if the lower cover  140  is inwardly bent, because the number of times of being is limited, it cannot perfectly absorb an external impact. 
     In this respect, however, in the present invention, because the lower cover  140  is outwardly bent, the lower cover  140  can be bent by a desired number of times (e.g., three or four times). Of course, the present invention is not limited to the structure in which the lower cover  140  is outwardly bent, and may include the structure in which the lower cover is inwardly bent. 
     Meanwhile, as described above, because the lower cover  140  is outwardly bent, the inner side of the lower cover  140  forms a flat plane. In  FIG. 3 , the main support unit  125  is disposed between the surface of the lower cover  140  and the liquid crystal display panel  110  to fix the liquid crystal display panel  110 , but an inner surface of the lower cover  140  may be directly in contact with the liquid crystal display panel  110  to fix the liquid crystal display panel. 
     In  FIG. 3 , there is no any structure at an upper portion of the liquid crystal display panel  110 , but an upper cover may be provided at the upper portion of the liquid crystal display panel  110 , and in this case, the upper cover may be coupled with the lower cover  140 . 
     In the present invention, the number of times of bending of the lower cover or the shape of the bending may not be limited. The number of times of bending or the shape of the bent portion  140   a  are described for the sake of brevity, and the present invention is not limited thereto. In the present invention, the number of times of bending or the shape of the bent portion vary depending on the conditions such as the size or the like of the LCD device, and the bent portion may be bent any number of times or may have any shape so long as an impact applied from the exterior can be effectively absorbed. 
       FIG. 5  is a sectional view showing the structure of an LCD device according to another exemplary embodiment. In the LCD device according to the present exemplary embodiment, a bent portion  240   a  of a lower cover  240  is wound outwardly at least several times. Because the bent portion  240   a  has an ellipse shape, an impact applied from the exterior can be absorbed by the ellipse bent portion  240   a,  without being applied to a liquid crystal display panel  210 . In this case, the bent portion  240   a  may be bent in the ellipse shape several times depending on the size or the like of the liquid crystal display panel  210 . In addition, the bent portion  240   a  may have various other shapes such as a circular shape, as well as the ellipse shape. 
     As the present invention may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.