Patent Publication Number: US-2016228910-A1

Title: Tensioning apparatus for mask, mask sheet, and manufacturing system for mask

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/688,055 filed Nov. 28, 2012, which claims the benefit of Korean Patent Application No. 10-2012-0058417 filed in the Korean Intellectual Property Office on May 31, 2012, each disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Field 
     The described technology generally relates to a mask manufacturing system. 
     2. Description of the Related Technology 
     An organic light emitting diode (OLED) display generally includes two electrodes and an organic emission layer disposed therebetween, and electrons injected from one electrode and holes injected from the other electrode are coupled with each other on the organic emission layer to form excitons and the excitons emit light while emitting energy. 
     SUMMARY 
     One inventive aspect is a mask tensioning apparatus of a deposition mask used in the manufacture of an organic light emitting diode (OLED) display, a mask sheet, and a mask manufacturing system including the same. 
     Another aspect is a mask tensioning apparatus that saves installation space of a clamp and tensioning force application means for tensioning a mask sheet, a mask sheet, and a mask manufacturing system including the same. 
     Another aspect is a mask tensioning apparatus that easily combines a mask sheet on a mask frame including a plurality of openings, a mask sheet, and a mask manufacturing system including the same. 
     Another aspect is a mask tensioning apparatus which includes: a clamp supporting a mask sheet disposed on a mask frame to couple the mask sheet to the mask frame; and a tensioning means connected to the clamp and applying a tensioning force to the clamp to fix the mask sheet fixed by the clamp to the mask, wherein the clamp is arranged in a vertical or oblique direction with regard to the elongation direction of the mask sheet thereby supporting the mask sheet. 
     The clamp may be clamped to a protruding portion formed at an end portion of the mask sheet. 
     The protruding portion of the mask sheet may be formed at four edges of the mask sheet. 
     The tensioning means may apply the tensioning force to the mask sheet in the elongation direction of the mask sheet and may apply the tensioning force to the mask sheet in the vertical or oblique direction with regard to the elongation direction of the mask sheet. 
     A pressing member pressing the mask sheet in a side of the mask frame may be further included. 
     The pressing member may be formed as a pair to press both end portions of the mask sheet. 
     The pressing member may include a block of which a pressing surface pressing the mask sheet is formed of a rectangle shape or a roller of which the pressing surface is formed of a curved surface. 
     Another aspect is a mask sheet for an organic light emitting diode (OLED) display, as a mask sheet weld-coupled on a mask frame for the OLED, which includes a protruding portion formed to be clamped to an end portion with a clamp. 
     The protruding portion may be formed at four edges of the mask sheet. 
     Another aspect is a mask manufacturing system which includes: a mask frame; a mask sheet disposed on the mask frame; a mask tensioning apparatus including a clamp supporting the mask sheet to couple the mask sheet to the mask frame and a tensioning means connected to the clamp and applying a tensioning force to the clamp to fix the mask sheet fixed by the clamp to the mask; and a coupling means coupling the mask sheet to the mask frame, wherein the clamp is arranged in a vertical or oblique direction with regard to the elongation direction of the mask sheet thereby supporting the mask sheet. 
     The clamp may be clamped to a protruding portion formed at an end portion of the mask sheet. 
     The protruding portion of the mask sheet may be formed at four edges of the mask sheet. 
     The tensioning means may apply the tensioning force to the mask sheet in the elongation direction of the mask sheet and may apply the tensioning force to the mask sheet in the vertical or oblique direction with regard to the elongation direction of the mask sheet. 
     A pressing member pressing the mask sheet in a side of the mask frame may be further included. 
     The pressing member may be formed as a pair to press both end portions of the mask sheet. 
     The pressing member may include a block of which a pressing surface pressing the mask sheet is formed of a rectangle shape or as a roller of which the pressing surface is formed of a curved surface. 
     The mask frame may include a pair of first frames parallel to each other, and two or more second frames coupled to the pair of first frames in a direction perpendicular to the first frames and arranged to be separated from each other. 
     A plurality of mask sheets may be coupled to one opening formed by a pair of first frames and two adjacent second frames of the mask frame. 
     The coupling means may be a welding apparatus for welding the mask sheet to the mask frame. 
     The mask manufacturing apparatus may be disposed for the clamp to clamp the mask sheet in the vertical or oblique direction with regard to the elongation direction of the mask sheet such that the installation space of the clamp and the tensioning means may be reduced without the arrangement of the clamp and the tensioning means parallel to the elongation direction of the mask sheet at both end portions of the mask frame. 
     The mask manufacturing apparatus may tension the mask sheet after clamping the mask sheet in the vertical or oblique direction with regard to the elongation direction of the mask sheet by the clamp such that the clamping and the tensioning of the mask sheet may be performed without interference to the mask frame even though a plurality of openings coupled with the divided mask sheets are formed as the size of the mask frame is increased. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a mask manufacturing system according to a first embodiment. 
         FIG. 2  is a perspective view of a mask sheet used in a mask manufacturing system according to the first embodiment. 
         FIG. 3  is a perspective view of a mask tensioning apparatus of a mask manufacturing system according to the first embodiment. 
         FIG. 4  is a cross-sectional view showing a state of a mask tensioning apparatus of a mask manufacturing system according to the first embodiment while tensioning a mask sheet. 
         FIG. 5  is a cross-sectional view showing a state of a mask tensioning apparatus of a mask manufacturing system according to a second embodiment while tensioning a mask sheet. 
         FIG. 6  is a cross-sectional view of a mask tensioning apparatus of a mask manufacturing system according to a third embodiment. 
         FIG. 7  is a cross-sectional view showing a state of a mask tensioning apparatus of a mask manufacturing system according to the third embodiment while tensioning a mask sheet. 
         FIG. 8  is a cross-sectional view of a state in which a pressing member of a roller shape presses a mask sheet in a mask manufacturing system according to the third embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Generally, to form an organic emission layer, an organic material is deposited on a substrate, and to achieve this, a deposition source filled with the organic material is heated to evaporate the organic material and spray the same over the substrate. In this instance, to deposit the evaporated and sprayed organic material with a specific pattern, an opening is formed on a specific position to deposit it, and a deposition mask made of a metallic material is used for a remaining position. A deposition mask can be classified as either a divided mask or a non-divided mask according to the manufacturing method. A non-divided mask is manufactured by pulling a mother mask that is not divided in four directions by using clamps that are installed at four corners of the mask manufacturing device to apply tension to the mother mask sheet, and welding it to the mask frame. A divided mask is manufactured by pulling both ends of a mask sheet that is divided per cell by using a clamp that is installed in both ends of a mask manufacturing device to apply a tension force to the mask sheet, and welding it to the mask frame. 
     The division method provides good selectivity and is easy to repair so it has been widely applied in mass production environments. However, the divided mask has tensioning force applied in an elongation direction at both ends of the mask sheet after both ends of the divided mask sheet have been clamped. Thus, the clamp and the tensioner are positioned at both sides of the mask frame and occupy significant space that is proportional to the size of a frame. 
     As the size of the frame has increased with time and because the mask frame combined with the divided mask sheet includes a plurality of openings, when a number of divided mask sheets are combined at each opening, and the clamp and tensioning force application are installed at both ends of the mask frame, it becomes more difficult to clamp the divided mask sheet. 
     Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present disclosure. The drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification. 
       FIG. 1  is a perspective view of a mask manufacturing system according to a first embodiment.  FIG. 2  is a perspective view of a mask sheet used in a mask manufacturing system according to the first embodiment.  FIG. 3  is a perspective view of a mask tensioning apparatus of a mask manufacturing system according to the first embodiment.  FIG. 4  is a cross-sectional view showing a state of a mask tensioning apparatus of a mask manufacturing system according to the first embodiment while tensioning a mask sheet. 
     Referring to  FIG. 1 , a mask manufacturing system  1  includes a mask frame  2 , a mask sheet  20 , a mask tensioning apparatus  10 , and a coupling means  30 . 
     The mask frame  2  is a constituent element that is coupled with the mask sheet  20  to form a mask. As shown in  FIG. 1 , the mask frame  2  includes a pair of first frames  2   a  extending in a first direction and substantially parallel to each other, and at least two, for example, three second frames  2   b ,  2   c , and  2   d  extending in a second direction substantially perpendicular to the first frames  2   a  to be coupled to the first frames and arranged to be separated from each other. 
     In this case, in one of openings  3  formed by a pair of first frames  2   a  and two second frames  2   b  and  2   c  adjacent to each other of mask frame  2 , a plurality of mask sheets  20  may be coupled to be arranged in substantially parallel with the second direction as shown in  FIG. 1 . As described, the mask including a plurality of mask sheets  20  coupled to one opening  3  may be a divided mask. 
     Referring to  FIG. 2 , the mask sheet  20  coupled to the mask frame  2  includes a mask sheet body  22  having an opening  21  of a predetermined pattern, and protruding portions  24  protruded from both end portions of the mask sheet body  22 . 
     The protruding portions  24  of the mask sheet  20  are formed to protrude in a direction substantially vertical to an elongation direction of the mask sheet body  22  at four edges of the mask sheet body  22 . The protruding portion  24  may be formed of various shapes such as a thin plate shape to be coupled to a clamp. 
     In the present embodiment, the protruding portions  24  of the thin plate shape are formed to protrude at four edges of the mask sheet body  22  of a square shape, however the number and shape of the protruding portions formed at both end portions may be various in a case that the clamp is coupled to the protruding portion at both end portions of the mask sheet for tensioning the mask sheet. 
     To couple the mask sheet  20  of the above structure to the mask frame  2 , the mask manufacturing system  1  includes the mask tensioning apparatus  10  and the coupler  30 . The coupler  30  is used to couple the mask sheet  20  to the mask frame  2 . The coupler  30  may be a welding apparatus. 
     In one embodiment, the mask sheet  20  is fixed on the mask frame  2  by using the mask tensioning apparatus  10 , and a boundary region of the mask sheet  20  and the mask frame  2  are welded by using the welding apparatus to manufacture the mask. 
     Referring to  FIG. 3 , the mask tensioning apparatus  10  includes a clamp  12  and a tensioner  14 . 
     The clamp  12  is a constituent element that is clamped to the protruding portion  24  of the mask sheet  20  for the mask sheet  20  to be coupled to the mask frame  2  to fix the mask sheet  20 . 
     The tensioner  14  to apply the tensioning force to the clamp  12  is coupled at the rear side of the clamp  12 . A tensioning force measurer  13  is installed between the clamp  12  and the tensioner  14  to measure the tensioning force applied to the clamp. 
     The mask manufacturing system  1  include four mask tensioning apparatuses  10 , one for each clamp  12  to be respectively coupled to the protruding portions  24  formed at four edges of the mask sheet  20 . 
     Meanwhile, for the mask manufacturing system  1 , as shown in  FIG. 4 , the mask tensioning apparatus  10  is arranged in the direction substantially vertical to the elongation direction of the mask sheet  20  such that the clamp  12  of the mask tensioning apparatus  10  is coupled to the protruding portion  24  of the mask sheet  20 . 
     As shown in  FIG. 4 , the mask tensioning apparatus  10  in which the clamp  12  is coupled to the protruding portion  24  of the mask sheet  20  is formed for the mask sheet  20  to be tensioned in the elongation direction of the mask sheet  20 , that is, both side directions of the mask sheet  20 . 
     As described, in the state in which the clamp  12  of the mask tensioning apparatus  10  clamps the protruding portion  24  of the mask sheet  20  in the substantially vertical direction, the tensioner of the mask tensioning apparatus  10  tensions the mask sheet  20  in the elongation direction of the mask sheet  20  to couple the mask sheet  20  to the mask frame. 
     Referring to  FIG. 4 , when a distance between two second frames  2   b  and  2   c  of the mask frame  2  is referred to as L 1 , a length L M  of the elongation direction of the mask sheet  20  is longer than L 1 , thereby both end portions of the mask sheet  20  contact on two adjacent second frames  2   b  and  2   c  of the mask frame  2  in a state in which the mask sheet  20  is disposed on the two second frames  2   b  and  2   c  of the mask frame  2 . 
     As described, in the state in which the mask sheet  20  contacts the mask frame  2 , the welding apparatus bonds the contact portions of the mask sheet  20  and the mask frame  2  such that the mask sheet  20  is weld-bonded to the mask frame  2 . 
     The mask tensioning apparatus  10  may be connected to a base (not shown) fixed with the mask frame  2  or may be separated from the base in which the mask frame  2  is installed. 
     In one embodiment, the mask tensioning apparatus  10  is arranged in the direction substantially vertical to the mask sheet  20  coupled to the mask frame  2  such that the mask tensioning apparatus  10  may be positioned on both end portions of the mask sheet  20  on the mask frame  2  to be clamped without being disposed at an outer portion of the second frame of the mask frame  2 , that is, outside the second frames  2   b  and  2   d  in  FIG. 1 . 
     Accordingly, for the tensioning of the mask sheet by a comparative mask tensioning apparatus in both directions from both end portions of the mask frame, the comparative mask tensioning apparatus is installed at both sides of the mask frame such that the mask manufacturing system including the mask tensioning apparatus occupies the wide space, however the mask manufacturing system  1  according to an embodiment does not need to install the mask tensioning apparatus at both sides of the mask frame such that the installation space of the mask tensioning apparatus  10  may be saved. 
     Also, the mask tensioning apparatus  10  of the mask manufacturing system  1  according to an embodiment is clamped to the protruding portion  24  of the mask sheet  20  on the second frame  2   c  positioned at the center portion of the mask frame  2  including a plurality of openings for the tensioning of the mask sheet  20  such that the mask sheet  20  may be easily bonded to the openings of each mask frame  2  although the mask frame  2  has a plurality of openings. 
     Next, the mask manufacturing system according to another embodiment will be described with reference to accompanying drawings. 
       FIG. 5  is a cross-sectional view showing a state of a mask tensioning apparatus of a mask manufacturing system  1 ′ according to a second embodiment while tensioning a mask sheet. 
     In the description of the mask manufacturing system  1 ′ according to the second embodiment, the detailed description of the same constituents as the first embodiment is omitted and the mask manufacturing system  1 ′ according to the second embodiment is described while focusing on differences from the first embodiment. 
     Differently from the first embodiment, the mask manufacturing system  1 ′ according to the second embodiment is formed for the mask tensioning apparatus  10 ′ to tension the mask sheet  20  in an inclined direction for of the mask sheet, not the direction substantially vertical to the elongation direction of the mask sheet  20 . 
     For this purpose, in the mask tensioning apparatus  10 ′ of the mask manufacturing system  1 ′ according to the second embodiment, a clamp  12  is arranged in the inclination direction at a predetermined angle (a) with respect to the elongation direction of the mask sheet  20 . 
     The mask tensioning apparatus  10 ′ may be obliquely arranged with regard to the elongation direction of the mask sheet  20 , or only the clamp  12  coupled to the protruding portion  24  of the mask sheet  20  may be obliquely arranged. 
     To easily couple the mask tensioning apparatus  10 ′ in the inclination direction for the mask sheet  20 , the protruding portion  24  of the mask sheet  20  may be obliquely formed with regard to the elongation direction of the mask sheet  20 . 
     As described, when tensioning the mask sheet  20  in the state in which the mask tensioning apparatus  10 ′ is arranged in the direction inclined with respect to the elongation direction of the mask sheet  20 , the tensioning direction of the mask tensioning apparatus  10  may be a direction substantially parallel to the elongation direction of the mask sheet  20 . 
     For the mask manufacturing system  1 ′ of the second embodiment, while the mask tensioning apparatus  10 ′ is obliquely coupled to the protruding portion  24  of the mask sheet  20  with respect to the elongation direction of the mask sheet  20  for the tensioning of the mask sheet  20 , the welding apparatus welds the mask frame  2  and the contact portion of the mask sheet  20  to manufacture the mask. 
     At this time, the angle (a) at which the mask tensioning apparatus  10 ′ or the clamp  12  is inclined with respect to the elongation direction of the mask sheet  20  may be determined by considering the space occupied by the mask tensioning apparatus  10 ′, the magnitude of the tensioning force tensioning the mask sheet  20 , and the size of the mask tensioning apparatus  10 ′. 
     In the mask manufacturing system according to the second embodiment, the base structure and the number of mask tensioning apparatuses  10 ′ is similar to the mask manufacturing system according to the first embodiment such that the detailed description thereof is omitted. 
       FIG. 6  is a cross-sectional view of a mask tensioning apparatus of a mask manufacturing system according to the third embodiment.  FIG. 7  is a cross-sectional view showing a state of a mask tensioning apparatus of a mask manufacturing system according to the third embodiment while tensioning a mask sheet.  FIG. 8  is a cross-sectional view of a state in which a pressing member of a roller shape presses a mask sheet in a mask manufacturing system according to the third embodiment. 
     In the description of the mask manufacturing system according to the third embodiment, the detailed description of the same constituents as the above described embodiments is omitted and the mask manufacturing system according to the third embodiment is described while focusing on differences from the above-described embodiments. 
     Referring to  FIG. 6 , the mask manufacturing system  1 ″ according to the third embodiment includes a pressing member  40  added to the mask manufacturing system  1 ′ according to the second embodiment. 
     The pressing member  40  is a member to press the mask sheet  20  in a side of the mask frame  2  in a state in which the mask sheet  20  contacts the mask frame  2 . 
     The pressing member  40  may have a cross-section formed of a rectangular (or other polygonal) block shape as shown in  FIG. 7  such that the surface contacts the mask sheet  20  as a plane, for example, a square plane shape, or as a friction roller  42  of which the pressing surface is formed of a curved surface as shown in  FIG. 8 . 
     At this time, the pressing member  40  is formed to be separated from the mask sheet  20  to not press the mask sheet  20  in a state that the mask sheet  20  is separated from the mask frame  2 , as shown in  FIG. 6 . 
     As shown in  FIG. 7 , the pressing member is formed to press the upper portion of the second frames  2   b  and  2   c  at both end portions of the mask sheet  20  in the state that the mask tensioning apparatus  10 ″ is coupled to the protruding portion  24  of the mask sheet  20 . 
     As described, in the state that the pressing member  40  presses the mask sheet  20 , the mask tensioning apparatus  10 ″ tensions the mask sheet  20 . 
     At this time, in the state that the pressing member  40  presses the mask sheet  20 , the tensioning direction of the mask tensioning apparatus  10 ″ may be the direction substantially parallel to the elongation direction of the mask sheet  20 , the inclination direction of the mask sheet, or the direction substantially vertical to the elongation direction of the mask sheet. 
     In the state that the pressing member  40  does not press the mask sheet  20 , when the mask tensioning apparatus  10 ″ tension the mask sheet  20  in the direction substantially vertical to the elongation direction of the mask sheet  20 , the mask sheet  20  may not contact with but is separated from the mask frame  2  such that the welding may be difficult. 
     Accordingly, as shown in the third embodiment, the mask sheet  20  is pressed by using the pressing member  40  such that the mask sheet  20  may further easily contact the mask frame  2 . 
     At this time, the size and the shape of the pressing member  40  pressing the mask sheet  20  and the pressing degree may be appropriately selected by considering the welding position of the mask sheet. 
     In the mask manufacturing system according to the various embodiments, the mask tensioning apparatus including the clamp is moved in the direction except for the direction substantially parallel to the elongation direction of the mask sheet for the tensioning of the mask such that the tensioning of the divided mask is possible without the influence of the position of the mask frame installed with the mask sheet. 
     Accordingly, in the case of this tensioning, although the mask of the large size including a plurality of panels like  8 G is manufactured, it is not necessary to increase the size of the mask sheet to the entire region of the  8 G panel, and the control of the mask sheet is easy when manufacturing and repairing the mask. 
     While the above embodiments have been described with reference to the accompanying drawings, it is to be understood that the present disclosure is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.