Abstract:
A deposition apparatus includes: a deposition source including a spray nozzle linearly arranged in a first direction and discharging a deposition material; and a pair of angle control members disposed at both sides of the deposition source and controlling a discharging direction angle of the deposition material. Each angle control member includes a rotation axis parallel to the first direction, and a plurality of shielding plates installed about the rotation axis and separated from each other by a predetermined interval around the rotation axis. Although the deposition angle is changed according to the increasing of the process time, the deposition angle is compensated to form a uniform thin film. Also, the organic thin film may be uniformly deposited through each pixel of an organic light emitting diode (OLED) display, thereby increasing luminance uniformity for each pixel.

Description:
CLAIM OF PRIORITY 
     This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application earlier filed in the Korean Intellectual Property Office on the 31 of May 2012 and there duly assigned Serial No. 10-2012-0058418. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a deposition apparatus and a manufacturing method of an organic light emitting diode (OLED) display using the same, and more specifically, to a deposition apparatus for controlling an emission direction of a deposition material by an angle control member, and a manufacturing method of an organic light emitting diode (OLED) display using the same. 
     2. Description of the Related Art 
     Among display devices, an organic light emitting diode display having the advantages of a wide viewing angle, excellent contrast, and a fast response speed has been receiving attention as one of the next generation display elements. 
     In general, the organic light emitting diode display has a deposition structure wherein an emission layer is inserted between an anode and a cathode so that holes and electrons generated in the anode and the cathode are recombined in the emission layer for light emission, thereby realizing a color. However, in this structure, it is difficult to obtain high efficiency light emission so that a middle layer, such as an electron injection layer (EIL), an electron transport layer (ETL), a hole transport layer (HTL), and a hole injection layer (HIL), is selectively added and inserted between each electrode and the emission layer. 
     In the flat panel display, such as the organic light emitting diode (OLED) display, an organic material or metal used as the electrode employs a vacuum deposition method for depositing a corresponding material in a vacuum atmosphere and forming a thin film on a flat plate. In the vacuum deposition method, a substrate on which an organic thin film will be formed is positioned in a vacuum chamber, a fine metal mask (FMM) having the same pattern as a pattern to be formed, such as a thin film, is disposed closely thereon, and an organic material is evaporated or sublimated by using a deposition source unit to deposit it on the substrate. 
     In this vacuum deposition method, it is necessary to control a spray angle according to the characteristic of the deposition material and the pattern of the mask, and to control the spray angle so that it is not changed with the passage of time. 
     The above information disclosed in this Background section is only for enhancement of an understanding of the background of the invention, and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a deposition apparatus that uniformly forms a thin film by compensating for a deposition angle that is changed with the passage of time. 
     The present invention further relates to a manufacturing method of an organic light emitting diode (OLED) display that uniformly forms a thickness of a deposited thin film by controlling the angle of an angle control member so as to ensure a uniform deposition angle. 
     A deposition apparatus according to the present invention comprises: a deposition source including a spray nozzle linearly arranged in a first direction and discharging a deposition material; and a pair of angle control members disposed at both sides of the deposition source for controlling a discharging direction angle of the deposition material; wherein each angle control member includes a rotation axis parallel to the first direction, and a plurality of shielding plates installed relative to the rotation axis and disposed so as to be separated from each other by a predetermined interval around the rotation axis. 
     A plurality of shielding plates may be separately disposed while forming equivalent center angles. 
     The deposition apparatus may further include a rotation driver for rotating the rotation axis. 
     The deposition apparatus may further include a rotation controller for controlling the rotation driver so as to periodically rotate the shielding plate. 
     The deposition apparatus may further include a moving unit disposed on one side of each angle control member for controlling a distance between the angle control member and the deposition source. 
     A manufacturing method of an organic light emitting diode (OLED) display according to the present invention comprises: disposing a substrate so as to face a deposition source including a spray nozzle arranged in a first direction and discharging a deposition material; disposing a pair of angle control members respectively installed with a plurality of shielding plates around a rotation axis for controlling a discharging direction angle of the deposition material on both sides of the deposition source; discharging the deposition material onto the substrate so as to form a thin film on the substrate; and rotating the shielding plate of the angle control member. 
     The method may further include controlling a distance between the angle control member and the deposition source. 
     In the rotating of the shielding plate of the angle control member, the shielding plate may be periodically rotated with the passage of a predetermined period of time. 
     The deposition material may be an organic material forming an organic emission layer, and the thin film may be an organic emission layer. 
     According to exemplary embodiments of the present invention, a thin film having a desired thickness may be uniformly formed. Also, although the deposition angle is changed with an increase in the process time, the deposition angle is compensated so as to form a uniform thin film. 
     Also, the organic thin film may be uniformly deposited through each pixel of the organic light emitting diode (OLED) display, thereby increasing luminance uniformity for each pixel. 
     In addition, according to exemplary embodiments of the present invention, although the deposition material is attached to the angle control member so that the deposition angle of the deposition material is changed, the angle control member may be replaced without stopping the process so that the manufacturing yield may be improved. The manufacturing process is easy, a deposition apparatus may be easily applied to the manufacturing process of a large-sized substrate, and the manufacturing yield and the deposition efficiency may be improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which like reference symbols indicate the same or similar components, wherein: 
         FIG. 1  is a perspective view of a deposition apparatus according to an exemplary embodiment of the present invention. 
         FIG. 2  is a perspective view of an angle control member of a deposition apparatus according to an exemplary embodiment of the present invention. 
         FIG. 3A  and  FIG. 3B  are schematic diagrams showing a method of manufacturing an organic light emitting diode (OLED) display by using a deposition apparatus according to an exemplary embodiment of the present invention. 
         FIG. 4  is a flowchart showing a method of manufacturing an organic light emitting diode (OLED) display by using a deposition apparatus according to an exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A deposition apparatus and a method for manufacturing an organic light emitting diode (OLED) display according to embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the exemplary embodiments disclosed herein, but may be implemented in various different forms. The exemplary embodiments herein merely complete the disclosure of the present invention and fully provide an explanation of the invention to the person of ordinary skill in the art. Like reference numerals refer to like elements throughout the specification. 
     In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. In the drawings, for better understanding and ease of description, the thicknesses of some layers and areas are exaggerated. It will be understood that, when an element such as a layer, film, region, or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. 
     In addition, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. Furthermore, throughout the specification, “on” implies being positioned above or below a target element, and does not imply being necessarily positioned on the top on the basis of a gravity direction. 
       FIG. 1  is a perspective view of a deposition apparatus according to an exemplary embodiment of the present invention, and  FIG. 2  is a perspective view of an angle control member of a deposition apparatus according to an exemplary embodiment of the present invention. 
     Referring to  FIG. 1  and  FIG. 2 , a deposition apparatus according to an exemplary embodiment of the present invention includes deposition sources  100   a  and  100   b  and a pair of angle control members  200 . 
     In each drawing, for better understanding and ease of description, although a chamber is not shown, all constituents of  FIG. 1  are disposed in a vacuum chamber maintaining an appropriate vacuum degree. The deposition apparatus and a substrate S (shown in  FIGS. 3A and 3B ) formed with a thin film are disposed in the vacuum chamber. The substrate S faces, and is spaced apart from, the deposition apparatus, and the deposition apparatus and the substrate S may be relatively moved during deposition. When the substrate S is horizontally disposed, the deposition apparatus is spaced from and disposed under the substrate S, and a deposition material may be emitted upward, while when the substrate S is vertically disposed, the deposition apparatus is spaced from and disposed beside the substrate S in the horizontal direction and the deposition material maybe emitted in the horizontal direction. In an exemplary embodiment of the present invention, the deposition apparatus is disposed on a bottom surface of the vacuum chamber and the substrate S is horizontally disposed thereon, but the invention is not limited thereto, and the substrate S may be vertically disposed so that the deposition apparatus maybe disposed beside and spaced apart from the substrate in the horizontal direction. 
     The deposition sources  100   a  and  100   b , as a means for emitting a deposition material to be deposited on the substrate S, include a space (not shown) for receiving the deposition material, such as an organic material, therein. The space for receiving the deposition material can be formed with a ceramic material such as alumina (Al 2 O 3 ) or aluminum nitride (AlN) with excellent heat radiation, but the invention is not restricted thereto, and the space for receiving the deposition material can be formed with various materials with excellent heat radiation and thermal resistance. A heater (not shown), formed to be attached to and to surround an external side of the space for receiving the deposition material, can be provided on the external side thereof, and it heats and vaporizes the received deposition material. Spray nozzles  110   a  and  110   b  for spraying the deposition material that is vaporized or sublimated in the inner space of the deposition source are disposed on one side of the deposition sources  100   a  and  100   b , respectively, facing the substrate S. 
     The substrate S on which the deposition material will be formed can be formed so as to be quadrangular, and the deposition sources  100   a  and  100   b  can be configured to be linear deposition sources in which the spray nozzles  110   a  and  110   b , respectively, for discharging the deposition material are linearly arranged in correspondence to one side of the substrate S. As shown in  FIG. 1 , spray nozzles  110   a  and  110   b  can be disposed in one line, or the spray nozzles  110   a  and  110   b  can be disposed in multiple lines rather than being restricted to one line. Also, a plurality of deposition sources may be disposed in parallel, and in the present exemplary embodiment, the two deposition sources  100   a  and  100   b  may be disposed in parallel as an example. 
     The angle control members  200  are disposed as a pair at both sides of the deposition sources  100   a  and  100   b , and are formed on the emission path of the deposition material discharged from the spray nozzles  110   a  and  110   b  of the deposition sources  100   a  and  100   b , respectively, thereby performing a function of controlling the emission direction of the spray nozzles  110   a  and  110   b . When the deposition sources  100   a  and  100   b  represent linear deposition sources elongated in a first direction as shown in  FIG. 1 , the angle control members  200  can be formed in a lengthwise direction of the linear deposition sources  100   a  and  100   b , respectively, and can be disposed on the discharging path of the deposition material. 
     Each of the angle control members  200 , disposed at both sides of the deposition sources  100   a  and  100   b , includes a rotation axis  230  and a plurality of shielding plates  220 . The rotation axis  230  as a bar member is elongated in the first direction and is disposed in a direction parallel to the first direction. The shielding plates  220 , as a means for controlling the emission direction angle of the deposition material, are partially disposed on the emission path of the deposition material, and are formed in a plate shape extending according to the rotation axis  230 . Multiple shielding plates  220  are provided, are disposed so as to be spaced apart from each other by an interval with respect to the rotation axis  230 , and are rotated according to the rotation of the rotation axis  230 . In the present exemplary embodiment of  FIG. 2 , three shielding plates  220  are provided for each angle control member  200 , but the invention is not limited thereto. 
     The deposition material spayed from the spray nozzles  110   a  and  110   b  of the deposition sources  100   a  and  100   b , respectively, in the deposition process maybe attached to the shielding plates  220  disposed on the emission path of the deposition material, but if the deposition material attached to the shielding plates  220  is increased with the passage of time, the angle at which the deposition material is discharged may be changed. When providing a plurality of shielding plates  220 , the shielding plates  220  may be rotated and used after the passage of time so that it is not necessary to replace the shielding plates  220 , and the usage time may be increased, rather than a case in which one shielding plate is provided. 
     A plurality of shielding plates  220  are separately disposed while forming equivalent angles toward the center. For example, as shown in  FIG. 2 , in the case of three shielding plates  220 , the shielding plates  220  are separately disposed while forming an angle of 120 degrees. 
     A pair of supporters  210  of a bar shape for supporting both ends of the rotation axis  230  are formed, and the supporter  210  supports the rotation axis  230  so as to be disposed in the first direction as the length direction of the deposition sources  100   a  and  100   b . The rotation axis  230  may be rotated by a rotation driver (not shown) providing power, and the rotation driver is connected to the rotation axis  230  installed at both sides of the rotation axis  230  or may be disposed inside the supporter  210 . A rotation controller (not shown) may control the rotation driver for the shielding plate  230  so as to be periodically rotated after the passage of a predetermined period of time. When a plurality of deposition sources  100   a  and  100   b  are disposed in parallel, an angle control member  250  of a plate shape is disposed between the deposition sources  100   a  and  100   b , and may control the emission angle of the deposition material discharged from each deposition source. 
     Moving units  400  disposed at one side of each angle control member  200  and controlling a distance between the angle control member  200  and the deposition sources  100   a  and  100   b  may be further included. That is, the moving units  400  may control angle control members  200  disposed at both sides of the deposition sources  100   a  and  100   b  so as to be closer to or further from the deposition sources  100   a  and  100   b . A detailed description thereof will be provided later with reference to  FIG. 3A  and  FIG. 3B . 
     Next, an operation of the deposition apparatus and a manufacturing method of an organic light emitting diode (OLED) display according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings. 
       FIG. 3A  and  FIG. 3B  are schematic diagrams, and  FIG. 4  is a flowchart, showing a method of manufacturing an organic light emitting diode (OLED) display by using a deposition apparatus according to an exemplary embodiment of the present invention. 
     First, a substrate S is inserted into a vacuum chamber (not shown), and is then disposed so as to face the deposition sources  100   a  and  100   b  discharging the deposition material ( FIG. 4 , block  401 ). Also, a plurality of shielding plates  220   a  and  220   b  are installed around the rotation axes  230   a  and  230   b  ( FIG. 4 , block  402 ), and a pair of angle control members  200   a  and  200   b  for controlling the emission direction angle of the deposition material are respectively disposed at both sides of the deposition sources  100   a  and  100   b  ( FIG. 4 , block  403 ). 
     The deposition material received inside the deposition sources  100   a  and  100   b  is heated so as to be vaporized, and as shown in  FIGS. 3A and 3B , the deposition material is discharged through the spray nozzles  110   a  and  110   b  ( FIG. 4 , block  404 ). The discharged deposition material reaches the substrate S so as to form a thin film thereon. 
     While the deposition material is discharged onto the substrate S so as to form a thin film, the deposition material is deposited on both the substrate S and the angle control members  200   a  and  200   b  provided on the path on which the deposition material is discharged. When the deposition material is attached to a part of the angle control members  200   a  and  200   b  that is provided on the path on which the deposition material is discharged and is then solidified, the angle for discharging the deposition material can be changed. At this point, the rotation axes  230   a  and  230   b  are rotated so as to move other shielding plates  220   a  and  220   b  that are not disposed on the emission path of the deposition material into the emission path of the deposition material ( FIG. 4 , block  405 ). For example, when three shielding plates  220  (as seen in  FIGS. 3A and 3B ) are disposed while forming the center angles so as to be equivalent, the rotation axis  230  is rotated by 120 degrees after the passage of a predetermined time period. As described above, if the rotation axis  230  of  FIG. 2  is rotated, the shielding plate  220  is at the same position that is initially predetermined so that the deposition process may be continuously performed. That is, although the deposition material is attached to the shielding plate  220 , the usage time of the shielding plate  220  may be increased without stopping the deposition process and replacing the shielding plate  220 . 
     Referring to  FIGS. 3A and 3B , it is necessary to control the emission angle of the deposition material according to process conditions, such as the size of the substrate S and the distance between the substrate S and the deposition sources  100   a  and  100   b  ( FIG. 4 , block  406 ). For this purpose, the rotation angle of the shielding plates  220   a  and  220   b  of the angle control members  200   a  and  200   b , and the distance between the angle control members  200   a  and  200   b  and the deposition sources  100   a  and  100   b , may be controlled. As shown in  FIG. 3A , when the angle control members  200   a  and  200   b  of both sides of the deposition sources  100   a  and  100   b  become closer to the deposition sources  100   a  and  100   b , the emission angle of the deposition material may be decreased. In contrast, as shown in  FIG. 3B , when the angle control members  200   a  and  200   b  of both sides of the deposition sources  100   a  and  100   b  are moved so as to be further from the deposition sources  100   a  and  100   b , the emission angle of the deposition material may be increased. 
     Also, through a simulation process, the amount of the deposition material that is attached to the angle control members  200   a  and  200   b  depending on the process conditions including the process time and the deposition material, and the control of the discharging angle of the deposition material according to the passage of the process time, may be checked, and at this point, the shielding plates  220   a  and  220   b  of the angle control members  200   a  and  200   b  may be rotated after the passage of the predetermined time through the checked data ( FIG. 4 , block  407 ). 
     For example, when the deposition material is deposited on the substrate S so as to form the thin film, if the deposition material attached to the angle control members  200   a  and  200   b  is increased by an amount that changes the emission angle after the process time has passed, the shielding plates  220   a  and  220   b  of the angle control members  200   a  and  200   b  is controlled so as to be rotated by the predetermined angle. 
     The deposition material desirably includes an organic material for forming an organic emission layer, that is, subpixels for displaying red (R), green (G), and blue (B) in the organic light emitting diode (OLED) display. 
     While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention 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.