Abstract:
A patterning apparatus includes a stage arranged under a flexible substrate, a plurality of correction units arranged closely to the stage, attached to the flexible substrate, and configured to apply a tension force to the flexible substrate, and a pattern forming unit configured to form a pattern on the flexible substrate. The patterning apparatus corrects distortion of the flexible substrate by using the correction units.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority under 35 U.S.C. 119 to Korean Patent Application No. 10-2009-0123583, filed on Dec. 11, 2009, which is hereby incorporated by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Field of the Disclosure 
         [0003]    This disclosure relates to a patterning apparatus. 
         [0004]    2. Description of the Related Art 
         [0005]    In the modern information society, a demand on large, flat, and multifunctional displays increases in the field of a video industry. Also, a portable and light display capable of freely recording or exchanging information anytime is needed. 
         [0006]    A glass substrate used for a flat display is formed to have a predetermined thickness and may be easily broken due to the properties of glass. Accordingly, an additional protection window is needed for portable displays or large displays. Also, the glass substrate is difficult to be bent. 
         [0007]    Thus, to overcome the above difficulty of the glass substrate, that is, not easily being bent, a flexible substrate having properties of being unbreakable and being easily bent is used. Accordingly, technologies about ultra light, easy-to-carry, and flexible display devices as a substrate having the above properties are under development. The flexible display device is economical, very durable, and freely installed on a curved surface. 
         [0008]    To embody the flexible display device, a flexible substrate such as plastic or metal foil is used. However, since the flexible substrate is flexible that is different properties of a glass substrate having a hard surface of a display device, the flexible substrate may be difficult to satisfy adaptability to a process. 
         [0009]    In other words, when a pattern, for example, a thin film transistor having a deposition structure or a plurality of lines, is formed on the flexible substrate, the property of being flexible may make it difficult to align the pattern. Thus, technologies to fix the flexible substrate using a fixing apparatus to facilitate transferring and processing of the flexible substrate have been suggested. 
       BRIEF SUMMARY 
       [0010]    Accordingly, the present embodiments are directed to a patterning apparatus that substantially obviates one or more of problems due to the limitations and disadvantages of the related art. 
         [0011]    An object of the present disclosure is to provide a patterning apparatus which may correct a distorted flexible substrate and precisely form a desired pattern. 
         [0012]    Additional features and advantages of the embodiments 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 embodiments. The advantages of the embodiments will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
         [0013]    According to one general aspect of the present embodiment, a patterning apparatus includes a stage disposed under a flexible substrate, a plurality of correction units being adjacent to the stage, attached to the flexible substrate, and applying a tension force to the flexible substrate, and a pattern forming unit forming a pattern on the flexible substrate. 
         [0014]    Other systems, methods, features and advantages will be, or will become, apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the following claims. Nothing in this section should be taken as a limitation on those claims. Further aspects and advantages are discussed below in conjunction with the embodiments. It is to be understood that both the foregoing general description and the following detailed description of the present disclosure are exemplary and explanatory and are intended to provide further explanation of the disclosure as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The accompanying drawings, which are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the disclosure. In the drawings: 
           [0016]      FIG. 1  illustrates a roll-to-roll system according to an embodiment of the present disclosure; 
           [0017]      FIG. 2  is a plan view illustrating a part of the roll-to-roll system of  FIG. 1 ; 
           [0018]      FIG. 3  is a perspective view illustrating a correction unit; 
           [0019]      FIG. 4  illustrates a roll-to-roll system according to another embodiment of the present disclosure; and 
           [0020]      FIG. 5  is a cross-sectional view taken along the line A-A′ of  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. In this disclosure, it will be understood that when an element, such as a substrate, a portion, a stage, a roller, or a pattern, is referred to as being formed “on” or “under” another element in the embodiments, it may be directly on or under the other element, or intervening elements (indirectly) may be present. The term “on” or “under” of an element will be determined based on the drawings. In the drawings, the sides of elements can be exaggerated for clarity, but they do not mean the practical sizes of elements. 
         [0022]      FIG. 1  illustrates a roll-to-roll system according to an embodiment of the present disclosure.  FIG. 2  is a plan view illustrating a part of the roll-to-roll system of  FIG. 1 .  FIG. 3  is a perspective view illustrating a correction unit. 
         [0023]    Referring to  FIGS. 1 through 3 , a roll-to-roll system according to the present embodiment includes an unwinding roller  100 , a winding roller  200 , a transfer roller  200 , a stage  500 , a plurality of correction units  600 , a support  700 , and a printing roller  800 . The unwinding roller  100  releases a flexible substrate  10 . That is, the flexible substrate  10  is wound around the unwinding roller  100  and then released from the unwinding roller  100  by the rotation of the unwinding roller  100 . 
         [0024]    The winding roller  200  winds the flexible substrate  10 . That is, the flexible substrate  10  where a pattern is formed winds around the winding roller  200  by the rotation of the winding roller  200 . The flexible substrate  10  is moved from the unwinding roller  100  to the winding roller  200 . That is, the flexible substrate  10  is moved in a first direction. The first direction is a direction in which the flexible substrate  10  is released and wound. 
         [0025]    The transfer roller  300  transfers the flexible substrate  10  in form of a flat panel. That is, the transfer roller  300  transfers the flexible substrate  10  from the unwinding roller  100  to the printing roller  800 . Also, the transfer roller  300  transfers the flexible substrate  10  from the printing roller  800  to the winding roller  200 . 
         [0026]    The stage  500  is disposed under the printing roller  800  and the flexible substrate  10 . The stage  500  supports the flexible substrate  10 . In particular, the stage  500  maintains the flat panel shape of the flexible substrate  10 . 
         [0027]    The stage  500  has a flat upper surface on which the flexible substrate  10  is placed. A plurality of first vacuum holes  510  are formed on the upper surface of the stage  500  and separated from each other at a constant interval. The stage  500  fixes the flexible substrate  10  by the suction force of the first vacuum holes  510 . The upper surface of the stage  500  may adhere to or be separated from a lower surface of the flexible substrate  10 . That is, the stage  500  is a vacuum chuck for fixing the flexible substrate  10 . 
         [0028]    The correction units  600  are disposed beside the stage  500 . The correction units  600  surround the stage  500 . The correction units  600  are disposed in a row around the stage  500 . The correction units  600  are disposed under the flexible substrate  10 . The correction units  600  adhere to the lower surface of the flexible substrate  10 . In detail, the correction units  600  may adhere to or be separated from the lower surface of the flexible substrate  10 . 
         [0029]    The correction units  600  apply a tension force to the flexible substrate  10 , in detail, in a horizontal direction. The correction units  600  may apply tension forces of different strengths to the flexible substrate  10 . Alternatively, the correction units  600  may apply the same tension force to flexible substrate  10 . 
         [0030]    Referring to  FIG. 3 , each of the correction units  600  includes a body  601 , a second vacuum hole  602 , and a servo motor  603 . The body  601  is disposed on the lower surface of the flexible substrate  10  to be capable of adhering to or being separated from the lower surface of the flexible substrate  10 . The body  601  may have elasticity and, for example, rubber based resin or polyurethane based resin may be used as a material for the body  601 . 
         [0031]    The second vacuum hole  602  is formed in the body  601  and provides a vacuum pressure to the flexible substrate  10 . The second vacuum hole  602  provides a vacuum pressure to the lower surface of the flexible substrate  10  by a vacuum pump (not shown) connected via a pipe  604 . The body  601  is sucked and adheres to the flexible substrate  10  by the vacuum pressure through the second vacuum hole  602 . 
         [0032]    The servo motor  603  is connected to the body  601  and drives the body  601 . That is, the servo motor  603  moves the body  601  in a horizontal direction. The body  601  is driven by the servo motor  603  and a tension force is applied to the flexible substrate  10 . 
         [0033]    The servo motor  603  is fixed to the support  700 . Also, the servo motor  603  may receive a driving signal through a driving circuit arranged at the support  700 . 
         [0034]    The correction units  600  include first correction units  610 , second correction units  620 , third correction units  630 , and fourth correction units  640 . The first correction units  610  are arranged in a row at one side surface of the stage  500 . The first correction units  610  apply a tension force to the flexible substrate  10  in the first direction. 
         [0035]    The second correction units  620  are arranged in a row at another side surface of the stage  500 . The second correction units  620  face the first correction units  610  with respect to the stage  500 . The second correction units  620  apply a tension force to the flexible substrate  10  in the first direction. 
         [0036]    The first and second correction units  610  and  620  may apply tension forces in the opposite directions. That is, when the first correction units  610  apply a tension force outwardly with respect to the flexible substrate  10 , the second correction units  620  may apply a tension force outwardly with respect to the flexible substrate  10 . Also, when the first correction units  610  apply a tension force inwardly with respect to the flexible substrate  10 , the second correction units  620  may apply a tension force inwardly with respect to the flexible substrate  10 . 
         [0037]    The third correction units  630  are arranged in a row at another side surface of the stage  500 . The third correction units  630  apply a tension force to the flexible substrate  10  in the second direction. 
         [0038]    The fourth correction units  640  are arranged in a row at another side surface of the stage  500 . The fourth correction units  640  apply a tension force to the flexible substrate  10  in the second direction. The stage  500  is arranged between the third and fourth correction units  630  and  640 . 
         [0039]    The third and fourth correction units  630  and  640  may apply tension forces in the opposite directions. That is, when the third correction units  630  apply a tension force outwardly with respect to the flexible substrate  10 , the fourth correction units  640  may apply a tension force outwardly with respect to the flexible substrate  10 . Also, when the third correction units  630  apply a tension force inwardly with respect to the flexible substrate  10 , the fourth correction units  640  may apply a tension force inwardly with respect to the flexible substrate  10 . 
         [0040]    Also, the first correction units  610  may be integrally formed or coupled, or integrally driven. Likewise, each of the second, third, and fourth correction units  620 ,  630 , and  640  may be integrally formed or coupled, or integrally driven. 
         [0041]    In this case, the first, second, third, and fourth correction units  610 ,  620 ,  630 , and  640  may be easily driven. Also, the distortion of a relatively simple structure such as symmetrical distortion may be easily corrected. 
         [0042]    The support  700  supports the correction units  600  by surrounding the correction units  600 . The correction units  600  are fixed at the inner side of the support  700 . 
         [0043]    The printing roller  800  is arranged above the flexible substrate  10 . As the printing roller  800  roles on the flexible substrate  10 , a pattern is formed. For example, the pattern is formed on the outer circumferential surface of the printing roller  800  and the pattern may be closely pressed against the flexible substrate  10 . 
         [0044]    Alternatively, an organic film for forming a pattern is formed on the upper surface of the flexible substrate  10  and, by applying a pressure to the organic film, the pattern may be formed on the flexible substrate  10 . 
         [0045]    Also, the printing roller  800  may employ a gravure, offset, or reverse offset method. Instead of the printing roller  800 , an imprinting roller, a stamping unit, or a photolithography unit is used to form a pattern on the flexible substrate  10 . 
         [0046]    The process of forming a pattern on the flexible substrate  10  will now be described. 
         [0047]    First, the unwinding roller  100  releases the flexible substrate  10  and the winding roller  200  winds the flexible substrate  10 . Also, transfer roller  300  rotates. Accordingly, a portion of the flexible substrate  10  where a pattern is to be formed is transferred to the printing roller  800 . 
         [0048]    A vacuum pressure is applied to the second vacuum hole  602  and thus the correction units  600  is sucked and adheres to the lower surface of the flexible substrate  10 . Then, the servo motor  603  is driven and thus a tension force is applied to the flexible substrate  10 . The flexible substrate  10  is corrected. The correction units  600  are driven separately. 
         [0049]    A vacuum pressure is applied to the first vacuum holes  510 . The lower surface of the flexible substrate  10  is sucked and adheres to the stage  500 . 
         [0050]    The printing roller  800  forms a pattern on the flexible substrate  10 . Then, the unwinding roller  100  releases the flexible substrate  10  and the winding roller  200  winds the flexible substrate  10 . The transfer roller  300  rotates. The portion of the flexible substrate  10  where the pattern is formed is transferred from the printing roller  800  to the outside. 
         [0051]    The flexible substrate  10  may be distorted due to heat, pressure, or chemicals. In particular, the flexible substrate  10  may be distorted not only in one direction but in a variety of methods of symmetric distortion, trapezoidal distortion, and non-symmetric distortion such as shear distortion and pincushion distortion. 
         [0052]    The correction units  600  are driven separately to correct the flexible substrate  10 . Thus, the correction units  600  may very precisely correct the flexible substrate  10 . In particular, the non-symmetric distortion may be easily corrected by the correction units  600 . Accordingly, the printing roller  800  may precisely form a pattern on the flexible substrate  10  so that misalign may be reduced. 
         [0053]      FIG. 4  illustrates a roll-to-roll system according to another embodiment of the present disclosure.  FIG. 5  is a cross-sectional view taken along the line A-A′ of  FIG. 4 . In the description of the present embodiment, referring to the descriptions about the above-described embodiment, the unwinding roller, the winding roller, and the correction units will be additionally described. The description about the above-described embodiment, except for the modified portions, may be substantially combined to the description about the present embodiment. 
         [0054]    Referring to  FIGS. 4 and 5 , an unwinding roller  101  and a winding roller  201  apply tension forces to the flexible substrate  10 . In detail, the unwinding roller  101  and the winding roller  201  apply tension forces to the flexible substrate  10 . Thus, the distortion of the flexible substrate  10  in the second direction is corrected by the unwinding roller  101  and the winding roller  201 . 
         [0055]    Also, a tension force may be applied to the flexible substrate  10  by the transfer roller  300 . The transfer roller  300  may correct the distortion of the flexible substrate  10  in the second direction. Correction units  650  and  660  are arranged on the stage  500 . The correction units  650  and  660  are arranged linearly along the outer edge portions of the flexible substrate  10 . 
         [0056]    Referring to  FIG. 5 , each of the correction units  650  and  660  includes a gripper  605 . The gripper  605  is fixed to the body  601  and applies a tension force to the flexible substrate  10  due to a frictional force. That is, the gripper  605  applies a tension force to the flexible substrate  10  in the first direction by the operation of the servo motor  603 . Since the gripper  605  needs to finely fix and control the flexible substrate  10 , the material and shape design of the gripper  605  is performed to have frictional properties. 
         [0057]    The gripper  605  has elasticity and is formed of a material, for example, flexible resin. In detail, for example, polyurethane resin, rubber based resin, or polyester based resin may be used as a material for the gripper  605 . 
         [0058]    The correction units  650  and  660  may be classified into fifth correction units  650  and sixth correction units  660 . The fifth correction units  650  are linearly arranged at one side of the flexible substrate  10 . The sixth correction units  660  are linearly arranged at another side of the flexible substrate  10 . 
         [0059]    The fifth and sixth correction units  650  and  660  may apply tension forces to the flexible substrate  10  in the opposite directions. That is, when the fifth correction units  650  apply a tension force outwardly with respect to the flexible substrate  10 , the sixth correction units  660  may apply a tension force outwardly with respect to the flexible substrate  10 . Also, when the fifth correction units  650  apply a tension force inwardly with respect to the flexible substrate  10 , the sixth correction units  660  may apply a tension force inwardly with respect to the flexible substrate  10 . 
         [0060]    Although the fifth correction units  650  may be separately driven, the fifth correction units  650  may be integrally formed or coupled, or integrally driven. Likewise, the sixth correction units may be integrally formed or coupled, or integrally driven. 
         [0061]    As such, the unwinding roller  101 , the winding roller  201 , and the correction units  650  and  660  apply tension forces to the flexible substrate  10  so that the distortion of the flexible substrate  10  is corrected. 
         [0062]    In a roll-to-toll system according to an embodiment of the present disclosure, while the winding roller  201  and the unwinding roller  101  are used to correct the distortion in the second direction, the correction units  650  and  660  are used to correct the distortion in the first direction. 
         [0063]    In the roll-to-toll system according to the present embodiment, the distortion of the flexible substrate  10  may be efficiently corrected by using a less number of correction units. 
         [0064]    Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments. 
         [0065]    Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.