Patent Publication Number: US-2012038780-A1

Title: Apparatus and method for inspecting display device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Korean Patent Application No. 10-2010-0077458, filed on Aug. 11, 2010, which is hereby incorporated by reference for all purposes as if fully set forth herein. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present application relates to an apparatus and method for inspecting a display device. 
     2. Discussion of the Related Art 
     Recently, the development of various types of portable electric equipment, such as mobile phones, personal digital assistants (PDAs) and notebook computers, is increasing due to the demands on flat panel display devices, which are small in size, lightweight and power-efficient and are thus applicable to those equipment. Examples of the flat panel display device are liquid crystal display (LCD) devices, plasma display panel (PDP) devices, field emission display (FED) devices, vacuum fluorescent display (VFD) devices and the like. Studies on these devices are actively conducted. Among others, LCD devices are currently in the limelight in view of their mass production technology, facilitation of driving scheme and implementation of high color rendering property. 
     LCD displays information on a screen by virtue of refractive index anisotropy of liquid crystal. As shown in  FIG. 1 , an LCD device  1  includes a first substrate  3 , a second substrate  5  and a liquid crystal (LC) layer  7  interposed between the first substrate  3  and the second substrate  5 . The first substrate  3  is a transistor array substrate. Although not shown, the first substrate  3  includes a plurality of pixels, each having a driving device, such as a thin film transistor (TFT). The second substrate  5  is a color filter substrate, which includes color filter layers for rendering real colors. Also, the first and second substrates  3  and  5  have a pixel electrode and a common electrode, respectively, and are coated with an alignment layer for aligning liquid crystal molecules of the LC layer  7 . 
     The first and second substrates  3  and  5  are bonded to each other by a sealing material  9 , and the LC layer  7  is formed between the sealing materials  9 . Accordingly, the driving devices formed on the first substrate  3  drive the liquid crystal molecules to control an amount of light transmitted through the LC layer  7 , thereby displaying information. 
     A fabrication process of the LCD device may be divided into a TFT array process of forming a TFT on the first substrate  3 , a color filter process of forming the color filter on the second substrate  5 , and a cell process, which will be described with reference to  FIG. 2  hereinafter. 
     As shown in  FIG. 2 , through the TFT array process and the color filter process, a TFT, namely, a driving device, and a color filter layer are formed respectively on the first substrate  3  and the second substrate  5 , as the mother-glass substrates have a plurality of liquid crystal panel regions (S 101  and S 104 ). Afterwards, an alignment layer is coated respectively on the first substrate  3  having the TFT and the second substrate  5  having the color filter layer for a rubbing process (S 102  and S 105 ). Liquid crystal is then dropped on the LC panel regions of the first substrate  3  and a sealing material  9  is coated along an edge region of the LC panel of the second substrate  5  (S 103 , S 106 ). 
     Afterwards, pressure is applied to the first and second substrate  3  and  5 , which are in an aligned state, so as to bond them to each other by the sealing material  9  and simultaneously to uniformly distribute the dropped liquid crystal (S 107 ). Through those processes, a plurality of liquid crystal panels having the LC layer are formed on the large glass substrate (i.e., first and second substrates  3  and  5 ). The glass substrate is then processed and cut out into a plurality of LC panels. Each LC panel is inspected, thereby fabricating an LCD device (S 108  and S 109 ). 
     As aforesaid, in the related art LCD fabrication method, the liquid crystal is dropped on the substrate, on which the plurality of LC panels are to be formed, and the first and second substrates  3  and  5  are bonded to each other to be divided into unit panels, thereby fabricating the LCD. 
     The LC panel may be inspected in various manners. A representative among them is an auto probe inspection using a vision auto probe (VAP) apparatus. The auto probe inspection is to automatically recognize a defective LC panel and defect location information using an area camera or a line camera. 
     The VAP apparatus includes a VAP frame defining an overall appearance, a work table for placing an LC panel thereon, a pad for applying a signal to the LC panel, a camera for receiving image information of the LC panel, a camera supporting frame for allowing movement of the camera, and the like. 
     In the meantime, the camera of the VAP apparatus is typically implemented using an area scan camera. In order to reduce a defect error rate of the LC panel, detection should be performed using the area scan camera with a high magnification ratio. However, the detection in the high magnification ratio may increase the number of area scan cameras, which causes an increase in a fabrication cost. 
     Also, even if the inspection is performed using the VAP apparatus by increasing the number of area scan cameras, an interruption may occur between the area scan cameras, thereby giving rise to difficulty of an accurate defect detection. 
     Furthermore, in order to detect spots where the LC panel looks like being stained as light is partially leaked according to a viewing angle (angular field) due to the lack of bonding margin or an incorrect bonding of the LC panel, a viewing angle inspection of the LC panel is needed. However, the area scan cameras cannot perform the viewing angle inspection, and consequently, such inspection is difficult to be performed. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to an apparatus and method for inspecting a display device that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. 
     An advantage of the present invention is to provide an apparatus and method for inspecting a display device that allows a fast inspection of the display device. 
     Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. These and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
     To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, an inspection apparatus for a display device may include a plurality of stages on which at least one display panel is loaded, and a first camera at one of the plurality of stages to photograph a display panel loaded on the corresponding stage with moving from one side to another side of the display panel to inspect a defect of the display panel. 
     The first camera may be a line scan camera, an area camera or time delay and integration (TDI) camera. The apparatus may further include a plurality of second cameras for viewing angle inspection, inclined by a preset angle in a diagonal direction of the display panel to execute a left and right viewing angle inspection of the display panel loaded on the corresponding stage. 
     One first camera may be disposed at each stage. Here, the first camera may photograph a display panel loaded on a stage with moving from one side to another of the display panel. 
     Also, when a plurality of first cameras are disposed at one stage and a plurality of display panels are loaded on the one stage, one of the first cameras may be moved to one region of a plurality of regions where the plurality of display panels are located on the corresponding stage so as to photograph a display panel present on the corresponding region, and another first camera may be moved to another region to photograph a display panel present on the corresponding region. 
     In accordance with another exemplary embodiment, an inspection apparatus for a display device may include a plurality of stages on which a plurality of display panels are loaded, respectively, and a plurality of first cameras to move among the plurality of stages, the plurality of first cameras photographing the plurality of display panels loaded on the respective stages, with moving from one side to another of the display panels, so as to inspect defects of the display panels. 
     Here, while one display panel is loaded on or unloaded from one stage, the first camera may photograph a display panel loaded on another stage. 
     In accordance with one exemplary embodiment, an inspection method for a display device may include loading display panels on a plurality of stages, respectively, and disposing at least one camera at each of a plurality of stages to photograph the display panel loaded on the corresponding stage, with moving the at least one camera from one side to another of the display panel, to inspect a defect of the display panel. 
     After a plurality of display panels are loaded on one stage or a plurality of stages, the loaded display panels can be scanned (photographed, taken, captured) simultaneously or sequentially by one camera or a plurality of cameras, thereby allowing a rapid inspection. Furthermore, upon loading or unloading one display panel, another display panel can be inspected, so as to realize an efficient inspection. 
     Also, viewing angle inspection cameras may also be equipped in addition to the camera(s), so as to allow a fast and accurate viewing angle inspection as well as a defect inspection. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. 
       In the drawings: 
         FIG. 1  is a schematic view illustrating a typical structure of an LCD device; 
         FIG. 2  is a flowchart illustrating a typical method for fabricating an LCD device; 
         FIG. 3  is a schematic view illustrating an apparatus for inspecting a display device in accordance with one exemplary embodiment; 
         FIG. 4  is a view illustrating an inspection part of the inspection apparatus; 
         FIG. 5  is a view illustrating a conveying path of the LC panel on the inspection apparatus; 
         FIGS. 6A to 6D  are views sequentially illustrating a method for inspecting an LC panel in accordance with one exemplary embodiment; 
         FIG. 7  is a view illustrating a viewing angle inspection camera of the inspection apparatus; and 
         FIG. 8  is a view illustrating a viewing angle inspection camera, having a plane mirror, of the inspection apparatus. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to embodiments of the present invention, example of which is illustrated in the accompanying drawings. The same reference numbers may be used throughout the drawings to refer to the same or like parts. 
     For a rapid inspection of a flat panel display device, a plurality of stages are prepared, and the flat panel display device is loaded on each stage to sequentially or simultaneously photograph the flat panel display device loaded on each stage using a camera, thereby performing inspection. The camera may be installed at each stage to photograph the flat panel display device loaded on the stage, or a single camera may be installed to photograph the flat panel display device loaded on each stage. Here, the flat panel display devices, which have undergone the preceding processes, are loaded sequentially, which allows a rapid inspection thereof. 
     Meanwhile, an inspection apparatus in accordance with the present invention can be used for various types of flat panel display devices, for example, an LCD device, an organic light emitting diode (OLED) device, a plasma display device and the like. Further, an inspection apparatus of the present invention may also be used for a solar cell. Hence, the following description herein exemplarily illustrates, but is not limited to, a specific flat panel display device. Rather, the inspection apparatus may also be applicable to any type of flat panel display devices. 
       FIG. 3  is a schematic view of an apparatus for inspecting a display device in accordance with one exemplary embodiment. As illustrated in  FIG. 3 , an inspection apparatus  100  inspects whether or not a display device fabricated through various processes has a defective portion, and may include a loader part, an inspection part and an unloader part. 
     The inspection apparatus  100  may include a conveyer  150  for conveying a display device, for example, an LC panel  201 , which has undergone various processes, such as a TFT process, a color filter process and the like, to the loader part, the inspection part and the unloader part, a first conveying unit  140  included in the loader part for loading a target to be inspected, such as the LC panel  201 , to convey to a palette  146 , a first camera  130   a  and a second camera  130   b  both installed at the inspection part for determining whether any defect is found on the LC panel  201  loaded on the palette  146 , and a second conveying unit  160  installed at the unloader part for unloading the LC panel  201  that has been inspected for determination as to existence or non-existence of a defect by scanning of the first and second cameras  130   a  ad  130   b.    
     Here, the LC panel  201  inspected in the inspection part may include a form of a cell or a form of a module. 
     The first conveying unit  140  may include a first lifting portion  145  for lifting up and down the LC panel  201  loaded by the conveyer  150  to transport to the palette  146 , and a second lifting portion  165  for lifting up and down the LC panel  201 , which is sent back by the conveyer  150  after the inspection process in the inspection part so as to unload the LC panel  201 . 
     Although not shown, the palette  146  may include a work table for placing the LC panel thereon to perform a defect inspection thereof, a probe unit attached onto the LC panel placed on the work table for applying an electric signal to the LC panel  201 , and a base plate having a probe unit for each of gate and data lines of the LC panel  201 . 
     The palette  146  may be provided one by one at the loader part, the inspection part and the unloader part. Accordingly, the palettes  146  may circulate in sequence of the loader part, the inspection part and the unloader part so as to sequentially transport the LC panels  201  to the loader part, the inspection part and the unloader part. 
     Here, at least two palettes  146  may be installed to consecutively transport the LC panels  201  by circulating the loader part, the inspection part and the unloader part, thereby allowing the rapid inspection of the LC panels  201 . 
     The first camera  130   a  and the second camera  130   b  may be disposed above the inspection part to photograph the loaded LC panels. Here, the first camera  130   a  and the second camera  130   b  may be a line scan camera for scanning the LC panel  201  by each line or an area camera for photographing the LC panel  201  by each area. 
     In the meantime, while running the LC panel  201 , if the line scan cameras  130   a  and  130   b  are used to perform a defect inspection, a driving signal having a specific period is applied to the LC panel  201 , thereby rendering an image having the specific period on the LC panel  201 . Consequently, a case where the line scan cameras  130   a  and  130   b  are difficult to acquire normal images may occur. 
     In this case, in place of the line scan cameras  130   a  and  130   b  for scanning line by line, a time delay and integration (TDI) camera, which scans a plurality of lines and accumulates images acquired from the plurality of lines so as to level the images, may be used. 
     Although not shown, the inspection apparatus  100  may include a vision hardware for processing information transferred from the first and second cameras  130   a  and  130   b  into images recognizable by an operator, an image display unit for displaying the images processed by the vision hardware, and a defect map for displaying defects of the LC panel  201 , which is inspected. 
     The inspection part of the inspection apparatus may further include a backlight unit (not shown) for emitting light to the LC panel  201  placed on the palette  146 . 
       FIG. 4  is a view illustrating the inspection part of the inspection apparatus  100  having the structure. 
     As illustrated in  FIG. 4 , the inspection part may include a base  110 , a first stage  120   a  and a second stage  120   b  installed on the base  110  for placing the transferred LC panel  201  thereon, first guide rails  136  installed on the base  110  for conveying the first stage  120   a  and the second stage  120   b  to portions where the first and second camera  130   a  and  130   b  are located, and second guide rails  132  installed on the base  110  for moving the first and second cameras  130   a  and  130   b.    
     As described above, the two stages  120   a  and  120   b  are installed at the inspection part such that the LC panel  201  can be loaded on each of them to be inspected. In other words, two sheets of LC panels  201  may be loaded to be inspected. Here, the LC panels may sequentially be loaded on the first and second stages  120   a  and  120   b  and photographed by the first and second cameras  130   a  and  130   b  for inspection. 
     Here,  FIG. 4  exemplarily shows that two cameras are installed at the stages  120   a  and  120   b , separately, so as to photograph the LC panels  201  loaded on the corresponding stages  120   a  and  120   b  for inspection. Alternatively, one camera may merely be installed at the two stages  120   a  and  120   b  to photograph each of the LC panels  201  loaded on each of the stages  120   a  and  120   b . In this structure, the LC panels may be sequentially or simultaneously loaded on each stage  120   a  and  120   b . Thereafter, the one camera may photograph the LC panel  201  loaded on one stage and then move to another stage to photograph the LC panel loaded thereon. Here, the previously inspected LC panel may be conveyed to the unloader part, and another LC panel  201  is loaded on this stage while the inspection is performed on another stage, thereby allowing a consecutive inspection. 
     Hereinafter, a method for inspecting the LC panel  201  using the inspection apparatus  100  having the structure will be described with reference to  FIGS. 3 and 4 . 
     Upon introducing an LC panel  201 , which is fabricated through several processes, such as the TFT array process, the color filter process, the bonding process and the like, into the inspection apparatus  100 , the LC panel  201  is loaded on the loader part. The loaded LC panel  201  is placed on the palette  146  by the first lifting portion  145  of the first conveying unit  140 . The LC panel  201  placed on the palette  146  is transported to the first stage  120   a  of the inspection part by the conveyer  150 . Afterwards, another LC panel  201  placed on the palette  146  is transported to the second stage  120   b  of the inspection part by the conveyer  150 . 
     As soon as the palette  146  is moved to the first stage  120   a , the palette  146  disposed at the unloader part is moved to the loader part to load the LC panel  201  thereon and thereafter moved to the second stage  120   b  of the inspection part. 
     The LC panel  201  transported to the loader part is placed on the work table provided at the palette  146  to be connected to the probe unit, thereby being under inspection as to existence or non-existence of a defect through the cameras  130   a  and  130   b . Here, images of an inspection sample photographed by the cameras  130   a  and  130   b  are processed by a light information processor, so an automatic inspection can be achieved. 
     Although not shown, the probe unit may include a probe base, a printed circuit board (PCB) base, a manipulator, a Pogo block, a TCP block and a probe block. The probe block may be in contact with a panel pad so as to allow inspection by photographing the LC panel  201  using the cameras  130  and  130   b.    
     The LC panel  201 , which has been completely inspected on the inspection part, is loaded on the palette  146  to be conveyed by the conveyer  150 . The LC panel  201  is then moved to the unloader part by being lifted up and down by the second lifting portion  165  of the second conveying unit  160 , so as to be unloaded. 
     The palette  146  moved to the unloader part is then moved back to the loader part, and another LC panel  201  introduced in turn is placed on the palette  146  to be on standby. 
     As such, the inspection apparatus  100  having the structure may include the plurality of palettes  146 , which circulate the loader part, the inspection part and the unloader part, so as to rapidly detect defective LC panels, which are sequentially loaded. 
       FIG. 5  is a schematic view illustrating a movement path of the LC panel  201  or the palette  146  in the inspection apparatus. The description of the movement path of the LC panel  201  or the palette  146  will specify the inspection process of the LC panel  201  more concretely. 
     Referring to  FIGS. 3 and 5 , the inspection apparatus  100  includes a loader part, an inspection part and an unloader part, each having four palettes. 
     A first LC panel  201   a  loaded on the palette  146   a  included in the loader part may be transported to a first stage  120   a  of the inspection part, and a palette  146   a  provided on the first stage  120   a  may be moved to the unloader part. That is, the first LC panel  201   a  is transported to the first stage  120   a  in the loaded state on the palette  146   a  to be photographed by the first camera  130   a . Afterwards, the first LC panel  201   a  is conveyed to the unloader part. Although not shown, the first LC panel  201   a  transported to the first stage  120   a  may be in contact with the probe unit provided at the first palette  146   a  to be photographed by the first camera  130   a , thereby being inspected as to whether or not a defect is present. When the first LC panel  201  a of the loader part is transported to the first stage  120   a , another first LC panel  201   a , which has been completely photographed on the first stage  120   a , is conveyed to the unloader part. 
     Also, a second LC panel  201   b  loaded on a second palette  146   b  included in the loader part may be transported to a second stage  120   b  of the inspection part and a palette provided on the second stage may be moved to the unloader part. That is, the second LC panel  201   b  is transported to the second stage  120   b  in the loaded state on the second palette  146   b  to be photographed by the second camera  130   b , thereby being conveyed to the unloader part. Although not shown, the second LC panel  201   b  transported to the second stage  120   b  may be in contact with the probe unit provided at the second palette  146   b  to be photographed by the second camera  130   b , thereby being inspected as to whether or not a defect is present. When the second LC panel  201   b  of the loader part is transported to the second stage  120   b , another second LC panel  201   b , which has been completely photographed on the second stage  120   b , is conveyed to the unloader part. 
     The first palette  146   a  provided at the unloader part is descended and moved to the loader part in a direction indicated with an arrow in the drawing. 
     As such, the plurality of stages  120   a  and  120   b  are provided, and the LC panels  201   a  and  201   b  are loaded on the stages  120   a  and  120   b  along different paths so as to be photographed by the cameras  130   a  and  130   b  installed at the respective stages  120   a  and  120   b , thereby being inspected. Here, even at the moment when the LC panels  201   a  and  201   b  are loaded on the respective stages  120   a  and  120   b , the photographing of an LC panel on another stage is in progress. 
     The first stage  120   a  and the second stage  120   b  of the inspection part may include a first backlight unit  148   a  and a second backlight unit  148   b , respectively. The first and second backlight units  148   a  and  148   b  may be run when the first and second LC panels  201  and  201   b  placed on the first and second palettes  146   a  and  146   b  are transported to the first and second stages  120   a  and  120   b  of the inspection part to be photographed by the cameras  130   a  and  130   b , thereby rendering test images on the first and second LC panels  201   a  and  201   b.    
     The first and second LC panels  201  and  201   b , which have completely undergone the defect inspection on the first and second stages  120   a  and  120   b  of the inspection part, are conveyed to the unloader part to be unloaded. Simultaneously, an LC panel, which has been transported to the loader part, is moved to the first and/or second stage(s)  120   a ,  120   b  of the inspection part and an LC panel, which has been transported to the unloader part, is moved to the loader part. 
     Therefore, an LC panel may be transported to the first or second stage  120   a  or  120   b  of the inspection part to be inspected as to whether or not a defect is present using the first or second camera  130   a  or  130   b , and another LC panel is loaded on the loader part to be on standby for the next turn. 
     As aforesaid, the inspection apparatus  100  having the structure may have the plurality of palettes, which circulate the loader part, the first and second stages of the inspection part and the unloader part, so as to rapidly detect whether or not targets to be inspected, provided sequentially, have a defect or not. 
     Hence, the plurality of stages of the inspection part are provided and a plurality of LC panels are simultaneously or sequentially loaded on those stages in the loaded state on the palettes. Afterwards, the LC panels transported by the palettes are photographed by the cameras installed at the respective stages, thus to be fast inspected. Here, the LC panels loaded on the respective stages may be sequentially loaded on the first and second stages by virtue of the conveyer. Also, the first and second cameras can be moved above the first and second stages to photograph those LC panels, which makes it possible to simultaneously or sequentially inspect the plurality of LC panels. 
     Meanwhile, the inspection apparatus  100  may not be limited to the structure of having two stages at the inspection unit and cameras installed above the respective stages so as to inspect an LC panel loaded on each stage. As an alternatively example, the inspection apparatus  100  may have a structure that three or more stages may be provided at the inspection part and a camera is installed above each stage to photograph a plurality of LC panels for inspection at one time, or a structure that three or more stages are provided at the inspection part and one camera is installed to photograph every LC panels loaded on the three or more stages. 
     Hereinafter, various configurations (structures) will be schematically described. In the following description, those configurations will be simplified to briefly describe an inspection method for LC panels using stages and cameras. However, the practical structures of those apparatuses will be understood with reference to  FIGS. 3 and 4 . 
     First, referring to  FIG. 6A , a plurality of stages  120   a  and  120   b  are provided at an inspection part (two stages are shown in the drawing but this disclosure may not be limited to the structure but be applicable to a structure of installing three or more stages). Cameras  130   a  and  130   b  may be installed at the stages  120   a  and  120   b , respectively. 
     LC panels  201   a  and  201   b  may be transported onto the stages  120   a  and  120   b  in a state of being loaded on palettes (not shown). Here, the stages  120   a  and  120   b  may be connected to a loader part and an unloader part via the conveyer  150  such that the LC panels  201   a  and  201   b  can be transported from the loader part to the first and second stages  120   a  and  120   b  and transported from the first and second stages  120   a  and  120   b  to the unloader part. Here, the LC panels  201   a  and  201   b  are transported to the first and second stages  120   a  and  120   b  in the state of being loaded on the palettes. However, the description of the palettes is omitted for the sake of brief description and rather the LC panels  201   a  and  201   b  are directly disclosed. 
     Here, the transport of the first and second LC panels  201   a  and  201   b  to the first and second stages  120   a  and  120   b  may be performed in a sequential manner. That is, after the first LC panel  201   a  is transported to the first stage  120   a  by the conveyer  150  (i.e., transported along the path indicated with {circle around ( 1 )} in the drawing), the second LC panel  201   b  is transported to the second stage  120   b  by the conveyer  150  (i.e., transported along the path indicated with {circle around ( 2 )} in the drawing). 
     After the first LC panel  201   a  is completely loaded on the first stage  120   a , the first camera  130   a  installed at the first stage  120   a  receives a test signal applied via a probe unit formed at the palette to photograph (scan) the first LC panel  201   a , on which a test image is displayed, thereby performing inspection of the first LC panel  201   a . Here, the first camera  130   a  may be a line scan camera or an area camera. The line scan camera may consecutively be moved by a linear motor or the like to photograph the first LC panel  201 , whereas the area camera may inconsecutively be moved by a step motor or the like to photograph a specific area. 
     The first camera  130   a  may be disposed at one side of the first stage  120   a . Upon the first LC panel  201   a  being loaded, the first camera  130   a  may move from the one side to another side to photograph the first LC panel  201   a  (i.e., photographing with moving along the path indicated with {circle around (A)} in the drawing). 
     Here, the first camera  130   a  may photograph the first LC panel  201   a  even at the moment when the second LC panel  201   b  is transported to the second stage  120   b  by the conveyer  150 . The completely photographed first LC panel  201   a  may then be conveyed to the unloader part by the conveyer  150  along path {circle around ( 1 )}. 
     After the second LC panel  201   b  is loaded on the second stage  120   b , the second camera  130   b  installed at the second stage  120   b  may receive a test signal applied via a probe unit formed at the palette to scan the second LC panel  201   b , on which a test image is displayed, thereby performing inspection of the second LC panel  201   b.    
     The second camera  130   b  may be disposed at one side of the second stage  120   b . Upon the second LC panel  201   b  being loaded, the second camera  130   b  may move from the one side to another side to photograph the second LC panel  201   b  (i.e., photographing with moving along the path indicated with {circle around (B)} in the drawing). 
     Here, the second camera  130   b  may photograph the second LC panel  201   b  even at the moment when the completely inspected first LC panel  201   a  is conveyed to the unloader part by the conveyer  150  along path {circle around ( 1 )}. The completely photographed second LC panel  201   b  may then be conveyed to the unloader part by the conveyer  150  along path {circle around ( 2 )}. 
     Thus, in the inspection apparatus with this structure, after the camera  130   a  and  130   b  are installed at the plurality of stages  120   a  and  120   b , respectively, the cameras  130   a  and  130   b  can be separately run to inspect the LC panels  201   a  and  201   b  loaded, thereby allowing a rapid inspection of the LC panels  201  and  201   b . Here, although not shown, to avoid interruption between the plurality of LC panels  201   a  and  201   b  when the plurality of LC panels  201   a  and  201   b , which have undergone the previous bonding process and cutting process, are loaded on or unloaded from the plurality of stages  120   a  and  120   b , a buffer unit may be provided to temporarily keep the LC panels  201   a  and  201   b  for a sequential transport of the LC panels  201   a  and  201  loaded on or unloaded from the plurality of stages  120   a  and  120   b.    
       FIG. 6B  illustrates a structure of an inspection apparatus that a plurality of stages  220   a  and  220   b  are provided at an inspection part and one camera  230  is installed, so as to inspect LC panels  201   a  and  201   b  loaded on the plurality of stages  120   a  and  120   b  by using the one camera  230 . 
     As illustrated in  FIG. 6B , the first and second LC panels  201   a  and  201   b  may be transported to the first stage  220   a  and the second stage  220   b , respectively, in a state of being loaded on palettes (not shown). Here, the first stage  220   a  and the second stage  220   b  may be connected to a loader part and an unloader part via a conveyer  250  such that the first and second LC panels  201   a  and  201   b  can be transported from the loader part to the first and second stages  220   a  and  220   b  and transported from the first and second stages  220   a  and  220   b  to the unloader part. 
     Here, the transport of the first and second LC panels  201   a  and  201   b  to the first and second stages  220   a  and  220   b  may be performed in a sequential manner. That is, after the first LC panel  201   a  is transported to the first stage  220   a  by the conveyer  250  (along path {circle around ( 1 )}), the second LC panel  201   b  is transported to the second stage  220   b  by the conveyer  250  (i.e., along path {circle around ( 2 )}). 
     The camera  230  may be installed at a specific stage  220   a ,  220   b  or outside the stages  220   a  and  220   b  so as to be movable to inside and outside of the stages  220   a  and  220   b.    
     After the first and second LC panels  201   a  and  201   b  are loaded on the first and second stages  220   a  and  220   b , respectively, the camera  230  may scan the first and second LC panels  201   a  and  201   b  so as to perform the inspection of the LC panels  201   a  and  201   b.    
     Here, the camera  230  may cover both the first and second stages  220   a  and  220   b . That is, the camera  230  may be moved toward the stages  220   a  and  220   b  having the LC panels  201   a  and  201  loaded so as to scan the loaded LC panels  201   a  and  201  within the stages  220   a  and  220   b , thereby performing the inspection. 
     When the first LC panel  201   a  is loaded on the first stage  220   a , the camera  230  is moved to the first stage  220   a  along path {circle around (A)}, and then moved or reciprocated in the first stage  220   a  along path {circle around (B)} to photograph the first LC panel  201   a  for inspection. 
     When the second LC panel  201   b  is loaded on the second stage  220   b , the camera  230  is moved to the second stage  220   b  along path {circle around (A)}, and then moved or reciprocated in the second stage  220   b  along path {circle around (C)} to photograph the second LC panel  201   b  for inspection. 
     The photographing of the camera  230  may be continued while transporting the LC panels  201   a  and  201   b . That is, at the moment when the second LC panel  201   b  is transported to the second stage  220   b  by the conveyer  250 , the camera  230  is moved to the first stage  220   a  along path {circle around (A)}, and thereafter moved or reciprocated along path {circle around (B)} to photograph the first LC panel  201   a . Also, at the moment when the first LC panel  201   a  is transported from the first stage  220   a  a to the unloader part by the conveyer  250 , the camera  230  is moved to the second stage  220   b  along path {circle around (A)}, and then moved or reciprocated in the second stage  220   b  along path {circle around (C)} to photograph the second LC panel  201   b . Also, the movement of the camera  230  will be the same in the reverse case. 
     As such, in the inspection apparatus with this structure, the one camera  230  may be installed at the plurality of stages  220   a  and  220   b  to be moved above the plurality of stages  220   a  and  220   b  so as to scan the LC panels  201   a  and  201   b  loaded on the respective stages  220   a  and  220   b , thereby allowing a rapid inspection of the LC panels  201   a  and  201   b . In addition, since the LC panels  201   a  and  201   b  are sequentially loaded on the stages  220   a  and  220   b  to be inspected and an inspection of another LC panel on another stage is in progress while the LC panels  201   a  and  201   b  are transported, the rapid inspection can be implemented. 
     Also, the buffer unit may also be provided in this inspection apparatus to avoid interruption between the plurality of LC panels  201   a  and  201   b  passed through the previous bonding process and cutting process when they are loaded on or unloaded from the plurality of stages  220   a  and  220   b.    
       FIG. 6C  illustrates an inspection apparatus having a structure that a plurality of cameras  330   a  and  330   b  are installed at one stage  320  of an inspection part and a plurality of LC panels  201   a  and  201   b  are loaded on the one stage  320  to be inspected. 
     As illustrated in  FIG. 6C , in this structure, the first and second LC panels  201   a  and  201   b  may be transported to the one stage  320  in a state of being placed on palettes (not shown). Here, the stage  320  may be connected to a loader part and an unloader part via a conveyer  350 , such that the first and second LC panels  201   a  and  201   b  can be transported from the loader part to the stage  320  and transported from the stage  320  to the unloader part. 
     Here, the transport of the first and second LC panels  201   a  and  201   b  to the stage  320  may be performed in a sequential manner. That is, after the first LC panel  201   a  is transported to one region of the stage  320  by the conveyer  350  (along path {circle around ( 1 )}), the second LC panel  201   b  is transported to another region of the stage  320  by the conveyer  350  (i.e., along path {circle around ( 2 )}). 
     First and second cameras  330   a  and  330   b  may be moved within the stage  320  to scan the LC panels  201   a  and  201   b  loaded on the different regions. 
     The first and second cameras  330   a  and  330   b  may be disposed at one side of the stage  320 . Upon the first LC panel  201   a  being loaded, the first camera  330   a  is moved from one side to another side along path {circle around (A)} to thereafter scan the first LC panel  201   a  along path {circle around (C)}. Here, the first camera  330   a  may scan (photograph) the first LC panel  201   a  even at the moment when the second LC panel  201   b  is transferred to the stage  320  by the conveyer  350 . The completely photographed first LC panel  201   a  may then be conveyed to the unloader part by the conveyer  350  along path {circle around ( 1 )}. 
     After the second LC panel  201   b  is loaded on the stage  320 , the second camera  330   b  is moved from one side to another side along path {circle around (B)} to thereafter scan the second LC panel  201   b  along path {circle around (D)}. Here, the second camera  330   b  may scan (photograph) the second LC panel  201   b  even at the moment when the first LC panel  201   a  is transferred to the unloader part by the conveyer  350 . The completely photographed second LC panel  201   b  may then be transferred to the unloader part by the conveyer  350  along the path {circle around ( 2 )}. Also, the second camera  330   b  may scan the second LC panel  201   b  even at the moment when the first camera  330   a  scans the first LC panel  201   a.    
     Meanwhile, the first and second cameras  330   a  and  330   b  may not scan the LC panels  201   a  and  201   b  loaded on specific regions of the stage  320 , respectively. That is, the fist camera  330   a  may scan either the first LC panel  201   a  loaded on the stage  320  or the second LC panel  201   b  loaded on the stage  320 . In other words, one of the first and second cameras  330   a  and  330   b  may scan, if necessary, both the two LC panels  201   a  and  201   b  loaded on the stage  320 . 
     As such, in the inspection apparatus with this structure, the plurality of cameras  330   a  and  330   b  are installed at the one stage  320  to scan the LC panels  201   a  and  201   b , respectively, thereby allowing a rapid inspection of the LC panels  201   a  and  201   b . Here, although not shown, to avoid interruption between the plurality of LC panels  201  a and  201   b  when the plurality of LC panels  201   a  and  201   b , which have undergone the previous bonding process and cutting process, are loaded on or unloaded from the stage  320 , a buffer unit may be provided to temporarily keep the LC panels  201   a  and  201   b.    
       FIG. 6D  illustrates an inspection apparatus having a structure that one camera  430  is installed at one stage  420  and a plurality of LC panels  201   a  and  201   b  are loaded on the one stage  420  for inspection. 
     As illustrated in  FIG. 6D , the first and second LC panels  201   a  and  201   b  may be transported to the one stage  420  in a state of being loaded on palettes (not shown). Here, the stage  420  may be connected to a loader part and an unloader part via a conveyer  450 , such that the first and second LC panels  201   a  and  201   b  can be transported from the loader part to the stage  420  and transported from the stage  420  to the unloader part. 
     Here, the transport of the first and second LC panels  201   a  and  201   b  to the stage  420  may be performed in a sequential manner. That is, after the first LC panels  201   a  is transported to one region of the stage  420  by the conveyer  450  (along path {circle around ( 1 )}), the second LC panel  201   b  is transported to another region of the stage  420  by the conveyer  450  (i.e., along path {circle around ( 2 )}). 
     The camera  430  may be moved from one side to another side of the stage  420 . After the first and second LC panels  201   a  and  201   b  are loaded on the stage  420 , the camera  430  may scan the first and second LC panels  201   a  and  201   b  to perform inspection. 
     Here, the camera  430  may be moved from one side to another side of the entire stage  420 . That is, the camera  430  may be moved within the stage  420 , on which the LC panels  201   a  and  201   b  are loaded, and scan the LC panels  201   a  and  201   b  loaded on the respective regions of the stage  420  to perform inspection. 
     When the first LC panel  201   a  is loaded on one region of the stage  420 , the camera  430  is moved within the stage  420  along path {circle around (A)} to be present above the first LC panel  201   a , and in this state, moved or reciprocated along path {circle around (B)} to scan the first LC panel  201   a.    
     After a complete inspection, the first LC panel  201   a  may be transported from the state  420  to the unloader part by the conveyer  450 . Simultaneously, the camera  430  is moved to another region of the stage  420  along path {circle around (A)} and thereafter moved or reciprocated along path {circle around (C)} to scan the second LC panel  201   b  loaded on the corresponding region. 
     Here, the scanning of the first LC panel  201   a  by the camera  430  may be executed even at the moment when the second LC panel  201   b  is transported to the stage  420 , and also the scanning of the second LC panel  201   b  by the camera  430  may be executed even at the moment when the first LC panel  201   a  is transferred to the unloader part. 
     As such, in the inspection apparatus with this structure, the one camera  430  is installed at the one stage  420 . However, after the plurality of LC panels  201   a  and  201   b  are loaded on the stage  420 , the camera  430  may be moved above the stage  420  to scan the plurality of LC panels  201   a  and  201   b , thereby allowing a rapid inspection. In addition, since the LC panels  201   a  and  201   b  are sequentially loaded on the stage  420  to be inspected and another LC panel are inspected during transport of the LC panels  201   a  and  201   b  (or the LC panels are transported during scanning of the LC panels  201   a  and  201   b ), the rapid inspection can be implemented. 
     Also, in the inspection apparatus with this structure, a buffer unit may be provided to avoid interruption between the plurality of LC panels  201   a  and  201   b  when the plurality of LC panels  201   a  and  201   b , which have undergone the previous bonding process and cutting process, are loaded on or unloaded from the stage  420 . 
     As aforesaid, after a plurality of LC panels  201   a  and  201   b  are loaded on one stage or a plurality of stages, the plurality of LC panels  201   a  and  201   b  can be simultaneously or sequentially photographed (scanned) by one camera or a plurality of cameras, which allows a rapid inspection. Furthermore, when one LC panel is loaded or unloaded, another LC panel can be inspected, resulting in allowing an efficient inspection. 
     Meanwhile, the present disclosure may not be limited to the inspection as to existence or non-existence of a defect on the LC panels  201   a  and  201   b  by photographing test images rendered on the LC panels  201   a  and  201   b  using a camera disposed above the LC panel  201   a  and  201   b  to scan them, but can also execute a viewing angle inspection of the LC panels  201   a  and  201   b.    
     That is, the inspection part may further include a viewing angle inspection camera located in a diagonal direction with an inclination angle of about 45° for performing a viewing angle inspection. An angle of the viewing angle inspection camera may be adjustable such that the viewing angle inspection camera can be inclined from a left/right direction of the LC panel  201   a ,  201   b  to the diagonal direction thereof for viewing angle inspection of the LC panel  201   a ,  201   b . Here, the viewing angle inspection camera may be a line scan camera. 
       FIG. 7  illustrates a camera  130  for detecting a defect of an LC panel  201  by taking test images and viewing angle inspection cameras  131  and  132  for inspecting a viewing angle. 
     As illustrated in  FIG. 7 , the defect inspection camera  130  may be disposed above the front of an LC panel  201 , and the first viewing angle inspection camera  131  and the second viewing angle inspection camera  132  may be disposed above both side surfaces thereof. The first viewing angle inspection camera  131  may scan the LC panel  201  in an inclined state from the left direction to the diagonal direction of the LC panel  201 , and the second viewing angle inspection camera  132  may scan the LC panel  201  in an inclined state from the right direction to the diagonal direction of the LC panel  201 , thereby executing the left/right viewing angle inspection of the LC panel  201 . 
     Thus, the inspection apparatus for the display device in the detailed description can substitute the existing method of inspecting a viewing angle by inspector&#39;s naked eyes, by employing the viewing angle inspection cameras  131  and  132 , thereby realizing an accurate and fast inspection. 
     Here, the viewing angle inspection cameras  131  and  132  may inspect viewing angles by being inclined in a certain direction. In this case, a focal point may differ and accordingly a screen may partially look stained, which disables defect detection or causes a detection error. 
     Referring to  FIG. 8 , a plane mirror  137  may be provided between the LC panel  201  and the viewing angle inspection camera  131  to avoid the detection error. Accordingly, an image, which is incident on the LC panel  201 , may be reflected in directions {circle around (A)} and {circle around (B)} perpendicular to a detection surface, thereby making a focal distance within the detection surface the same. An image with the same focal distance may be obtained as a clear image within the viewing angle inspection camera  131 . 
     An angle of the plane mirror  137  may be calculated according to the following Equation. 
       α=90−β/2,
 
     wherein α denotes an angle of the plane mirror  137  and β denotes an off-axis angle between the LC panel  201  and the detection surface. 
     As described, after a plurality of LC panels are loaded on one stage or a plurality of stages, the loaded LC panels can be scanned (photographed, taken, captured) simultaneously or sequentially by one camera or a plurality of cameras, thereby allowing a rapid inspection. Furthermore, upon loading or unloading one LC panel, another LC panel can be inspected, so as to realize an efficient inspection. 
     Also, viewing angle inspection cameras may also be equipped in addition to the camera(s), so as to allow a fast and accurate viewing angle inspection as well as a defect inspection. 
     It will be apparent to those skilled in the art that various modifications and variation can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.