Abstract:
An apparatus includes a drop unit, a transfer unit and a position adjusting unit. The drop unit drops droplets of an organic material. The transfer unit transfers the drop unit along a first direction. The position adjusting unit is interposed between the drop unit and the transfer unit to adjust a position of the drop unit. Therefore, the apparatus of dropping the organic material has a small size and may drop droplets of the organic material onto an accurate position. Furthermore, the transfer unit moves the drop unit quickly, and the position adjusting unit adjusts the position of the drop unit accurately. Therefore, a time difference for drying the organic material injected into a cavity is reduced.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority to Korean Patent Application No. 2004-10892 filed on Feb. 19, 2004, the contents of which are herein incorporated by reference in its entirety. 
   BACKGROUND OF THE INVENTION 
   1. Technical Field 
   The present invention relates to an apparatus for depositing an organic material on a substrate. More particularly, the present invention relates to an apparatus for depositing an organic material droplet on a substrate. 
   2. Discussion of the Related Art 
   Generally, a display apparatus displays an image using data processed by an information processing apparatus. 
   The different types of display apparatus include a cathode ray tube (CRT) apparatus, a liquid crystal display (LCD) apparatus, an organic light emitting diode (OLED) apparatus, a plasma display panel (PDP), etc. The CRT displays an image by controlling an electron beam applied to a fluorescent layer. The LCD displays an image by orienting liquid crystals. The OLED displays an image by currents that flow through an organic light emitting layer. The PDP displays an image by plasma. 
   The OLED has features such as being thin in thickness, high luminance, full color, low power consumption, and low manufacturing cost, etc. 
   The OLED includes an anode electrode arranged in a matrix shape on a substrate, an organic layer formed on the substrate and having an opening through which a portion of the anode electrode is exposed, an organic light emitting layer formed on the anode electrode exposed by the organic layer, and a cathode electrode formed on the organic light emitting layer. 
   The organic light emitting layer of the OLED includes a hole injection layer (HIL), an emitting material layer (EML) and an electron injection layer (EIL). 
   The organic light emitting layer can be formed by processes such as a slit mask, a spin coating, a roll-to-roll, a vacuum deposition, etc. Recently, a dropping method is employed, wherein a droplet of an organic material is dropped into a cavity formed at the organic layer. 
   An apparatus for dropping a droplet of an organic material typically includes an organic material dropping unit and a transfer unit which transfers the organic material dropping unit. In the conventional apparatus, injecting the organic material at once into the cavity arranged in a matrix shape may be difficult. The conventional apparatus scans organic material cavities and injects the organic material into the cavities as the dropping unit traverses along the layer. 
   When a drying time of the organic material injected into the cavity is different, the organic light emitting layers of each cavity have a profile different from each other and light generated from an organic light emitting layer may have different luminance. Therefore, display quality is deteriorated. 
   Recently, an apparatus is used for simultaneously dropping organic materials along a layer to form a more uniform light emitting layer. 
   Such apparatus uses a plurality of organic material dropping units and a plurality of transfer units. The transfer units correspond to the organic material dropping units. However, such apparatus of dropping the organic material is larger in size. 
   SUMMARY OF THE INVENTION 
   An exemplary apparatus of dropping an organic material according to the present invention includes a drop unit, a transfer unit and a position adjusting unit. The drop unit drops droplets of the organic material. The transfer unit transfers the drop unit along a first direction. The position adjusting unit is disposed between the drop unit and the transfer unit to adjust a position of the drop unit. 
   In another exemplary apparatus of dropping an organic material according to the present invention, an apparatus includes at least two drop units, a transfer unit, a combination unit and a position adjusting unit. The drop units drop droplets of the organic material. The drop units can be arranged in series. The transfer unit transfers the drop units in a first direction. The combination unit is interposed between the drop units and the transfer unit to connect the drop units to the transfer unit. The position adjusting unit is interposed between the drop units and the combination unit so as to adjust a distance between the drop units and adjust a position of the drop units. 
   In another exemplary apparatus of dropping an organic material according to the present invention, an apparatus includes a first drop apparatus, a second drop apparatus, a first position adjusting unit and a second position adjusting unit. The first drop apparatus includes a first drop unit that drops droplets of the organic material, and a first transfer unit that is connected to the first drop unit to transfer the first drop unit along a first direction. The second drop apparatus includes a second drop unit that drops droplets of the organic material, and a second transfer unit that is connected to the second drop unit to transfer the second drop unit along the first direction. The second drop apparatus is spaced apart from the first drop apparatus along a second direction that is substantially perpendicular to the first direction. The first position adjusting unit is interposed between the first drop unit and the first transfer unit to adjust a position of the first drop unit. The second position adjusting unit is interposed between the second drop unit and the second transfer unit to adjust a position of the second drop unit. 
   According to an illustrative embodiment of the present invention, an apparatus of depositing organic material accurately deposits droplets of the organic material onto target positions. 
   Furthermore, a transfer unit moves the drop unit quickly, and the position adjusting unit accurately adjusts the position of the drop unit. Therefore, the time difference for drying the organic material injected into cavities is reduced. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other features of the present invention will become more apparent by describing in detailed exemplary embodiments thereof with reference to the accompanying drawings, in which: 
       FIG. 1  is a schematic view illustrating an apparatus of dropping an organic material according to an embodiment of the present invention; 
       FIG. 2  is a schematic view illustrating an apparatus of dropping an organic material having a data processing unit according to an exemplary embodiment of the present invention; 
       FIG. 3  is a schematic view illustrating an apparatus of dropping an organic material according to another exemplary embodiment of the present invention; 
       FIG. 4  shows details of a transfer unit in an apparatus of dropping an organic material; 
       FIG. 5  shows an apparatus of dropping an organic material with a guide rail according to an exemplary embodiment of the present invention; 
       FIG. 6  is a schematic view illustrating an apparatus of dropping an organic material according to another embodiment of the present invention; 
       FIG. 7  is a schematic view illustrating an apparatus of dropping an organic material according to still another embodiment of the present invention; and 
       FIG. 8  is a perspective view of an apparatus of dropping an organic material according to another embodiment of the present invention. 
   

   DESCRIPTION OF EMBODIMENTS 
     FIG. 1  is a schematic view illustrating an apparatus of dropping an organic material according to a first exemplary embodiment of the present invention. Referring to  FIG. 1 , an apparatus  100  includes a drop unit  110 , a transfer unit  120  and a position adjusting unit  130 . The drop unit  110  deposits or drops droplets of the organic material such as an organic light emitting material, a composition of color filter, etc., onto a substrate  10  to form an organic pattern  20  on the substrate  10 . The drop unit  110  includes a plurality of nozzles  112 . The organic pattern  20  is formed using the organic material dropped through the nozzles  112 . The nozzles  112  are disposed to face the substrate  10 . The nozzles  112  are arranged such that a distance between the nozzles  112  is in a range from a few μm to hundreds of μm. 
   The drop unit  110  may further include an organic material providing unit  115  that provides the drop unit  110  with the organic material. The organic material providing unit  115  may include an organic material containing tank  114  and a pipe  113 . The organic material in the organic material containing tank  114  is transferred to the nozzle  112  through the pipe  113 . The organic material providing unit  115  may further include a Mass Flow Controller (MFC). The MFC controls an amount of the organic material that flows through the pipe  113 . 
   The transfer unit  120  transfers the drop unit  110 . When the drop unit  110  arrives at a predetermined point, the transfer unit  120  stops transferring the drop unit  110 . To accurately control the transfer unit  120  that stops the drop unit  110  at the predetermined point, the apparatus  100  includes the position adjusting unit  130 . The position adjusting unit  130  adjusts the predetermined point, so that the drop unit may drop the organic material accurately. The position adjusting unit  130  can move the drop unit  110  along the same direction as the direction which the transfer unit  120  moves the drop unit  110 . 
   Referring to  FIG. 2 , the position adjusting unit  130  further includes a position measuring unit  132  and a data processing unit  134 . The position measuring unit  132  measures a position of the drop unit  110  using a position detecting device. Preferably, the position detecting device takes a picture of an alignment key  30 , and the position measuring unit  132  measures a position of the drop unit  110  by using at least two alignment keys. A charge-coupled device (CCD) camera may be used as the position detecting device. 
   The data processing unit  134  receives position data containing position information of the drop unit  110  from the position measuring unit  132 , and processes the position data to form arrangement data. The arrangement data includes information of the drop unit  110 . For example, the arrangement data can indicate if the drop unit  110  is located at a proper position, or a distance between a target position and current position, etc. The arrangement data is applied to the position adjusting unit  130  for adjusting the position of the drop unit  110 . According to the present embodiment, the position of the drop unit  110  may be compensated by the position measuring unit  132  and the data processing unit  134 . Therefore, the drop unit  110  may be disposed more accurately. 
     FIG. 3  is a schematic view illustrating an apparatus of dropping an organic material according to another embodiment of the present invention. The apparatus of dropping the organic material of the present embodiment is same as in the above embodiment except for the position adjusting unit. The same reference numerals will be used to refer to the same or like parts as those described in the above embodiment. 
   Referring to  FIG. 3 , an apparatus  100  of dropping an organic material of the present embodiment includes a plurality of position adjusting units  130 . Two units  130   a  and  130   b  are shown for illustration. The position adjusting units  130  are fixed to a transfer unit  120  and as such the distance between the position adjusting units  130  remains the same when the position adjusting units  130  are moved. Each of the drop units  110  is coupled to and controlled by its respective position adjusting unit  130 . Preferably, the drop units  110  are spaced apart from each other by a distance equivalent to the widths of multiple nozzles  112  of the drop units  110 . 
   When a distance between the drop units  110  is different than the desired distance, the droplets of the organic material dropped by the nozzles  112  of the drop unit  110  may become irregular. The position adjusting units  130  can be used to adjust the distance between the drop units  110 . 
     FIG. 4  shows further details of a transfer unit  120  according to the present embodiment. The transfer unit  120  includes a conveyer belt  126  and driver units  122  and  124 . The conveyer belt  126  is preferably a closed curve belt. The driver units  122  and  124  are disposed inside the conveyer belt  126 , and spaced apart from each other such that the conveyer belt  126  has a predetermined tension. The driver unit  122  corresponds to a driver roller connected to a motor, and the driver unit  124  corresponds to a driven roller, or vice versa. The driver roller  122  drives the conveyer belt  126 , and the driven roller  124  is rotated by the conveyer belt  126  that is driven by the driver roller  122 . The position adjusting unit  130  is held to the conveyer belt  126 , and the drop unit  110  is installed at the position adjusting unit  130 . 
   In the present embodiment, the conveyer belt  126  transfers the position adjusting unit  130  and the drop unit  110 . Alternatively, the transfer unit  120  may employ other apparatus that may reciprocate the position adjusting unit  130 , for example, such as a hydraulic cylinder, a ball screw apparatus and so on. 
   As shown in  FIG. 4 , an apparatus of dropping the organic material employs the conveyer belt  126  as the transfer unit  120  that moves the position adjusting unit  130  and the drop unit  110 . 
   Referring to  FIG. 5 , when a transfer unit  120  transfers a position adjusting unit  130  and a drop unit  110 , the position adjusting unit  130  and a drop unit  110  may shift in position, so that the drop unit  110  may not drop droplets of the organic material onto a desired position. To stabilize the adjusting unit  130  and the drop unit  110 , an apparatus of dropping the organic material may include a guide rail  140  that guides the position adjusting unit  130 . 
   Alternatively, an additional guide rail (not shown) may be used to guide the drop unit  110 . Preferably, the position adjusting unit  130  rides on the guide rail  140  to prevent a shift in the position adjusting unit  130  and the drop unit  110 . The guide rail  140  can be a cylindrical rod shape. 
     FIG. 6  shows a drop unit in further detail. An apparatus  100  of dropping an organic material further includes a rotating unit  150 . The rotating unit  150  is interposed between a position adjusting unit  130  and a drop unit  110 . The rotating unit  150  rotates the drop unit  110  with respect to a substrate  10 . The rotating unit  150  includes a motor (not shown) and gears (not shown). 
   The nozzles  112  used for injecting the organic material may have a distance between nozzles that is smaller than a distance between the cavities  20  on the substrate  10 . According to the present embodiment, the use of the rotating unit  150 , facilitates depositing droplets of the organic material at cavities of which the distance is smaller than the distance between nozzles  112  of the drop unit  110 . 
     FIG. 7  is a schematic view illustrating an apparatus of dropping an organic material according to still another exemplary embodiment of the present invention. Referring to  FIG. 7 , an apparatus  100  of dropping an organic material includes a drop unit  110 , a transfer unit  120 , a combination unit  160  and a position adjusting unit  130 . 
   The apparatus  100  of dropping the organic material includes at least one drop unit  110 . In this illustrative embodiment, there are two drop units  110  arranged side by side along the path of travel. Each of the drop units  110  includes a plurality of nozzles  112 . The nozzles  112  are arranged linearly but can be arranged as in an array (not shown). The distance between the nozzles  112  is in a range from a few μm to hundreds of μm. An organic material providing unit  115  provides the drop units  110  with organic material. The organic material providing unit  115  may include an organic material containing tank  114  and a pipe  113 . The organic material in the organic material containing tank  114  is transferred to the nozzles  112  through the pipe  113 . The organic material providing unit  115  may further include a Mass Flow Controller (MFC). The MFC controls an amount of the organic material that flows through the pipe  113 . 
   The drop unit  110  may be combined with a rotating unit  150 . The rotating unit  150  rotates the drop unit  110  with respect to the substrate  10 . The rotating unit  150  includes a motor (not shown) and gears (not shown). Therefore, the apparatus  100  of dropping the organic material may provide cavities of which a distance is smaller than a distance between the drop nozzles  112 . A guide rail  140  is provided to guide the drop unit  110 . The transfer unit  120  transfers the drop unit  110 . The transfer unit  120  may use a transferring member such as a conveyer belt, a hydraulic cylinder, a ball screw apparatus and so on. 
   A combination unit  160  is coupled to transfer unit  120  to engage and transfer the position adjusting unit  130  and the drop unit  110 . The position adjusting unit  130  is interposed between the combination unit  160  and the drop unit  110  and controls a position of the drop unit  110  such that the drop unit  110  drops droplets of the organic material accurately onto targeted positions. 
   The position adjusting unit  130  may include a position measuring unit  132  and a data processing unit  134 . The position measuring unit  132  measures a position of the drop unit  110 . To measure the position of the drop unit  110 , the position measuring unit  132  includes a position detecting device that takes a picture of an alignment key  30 . For example, a charge-coupled device (CCD) camera may be used as the position detecting device. The position measuring unit  132  measures the position of the drop unit  110  by using at least two alignment keys  30 . The data processing unit  134  receives position data containing position information of the drop unit  110  from the position measuring unit  132 , and processes the position data to form arrangement data. The arrangement data includes information of the drop unit  110 . For example, the arrangement data can indicate if the drop unit  110  is located at a proper point, or a distance between a target and the current position, etc. The arrangement data are applied to the position adjusting unit  130  to adjust the position of the drop unit  110 . 
     FIG. 8  is a schematic view illustrating an apparatus of dropping an organic material according to still another embodiment of the present invention. Referring to  FIG. 8 , an apparatus  100  of dropping the organic material includes a first drop apparatus  200  and a second drop apparatus  300 . The first drop apparatus  200  includes a first drop unit  210 , a first transfer unit  220  and a first position adjusting unit  230 . 
   The first drop unit  210  drops the organic material, for example, an organic light emitting material, a composition of color filter, etc., toward a substrate  10 . Then, organic patterns  20  are formed on the substrate  10 . The apparatus  100  of dropping the organic material includes at least one first drop unit  210 . In the present embodiment, the apparatus  100  of dropping the organic material includes a plurality of the first drop units  210 . 
   The first drop units  210  are arranged side-by-side along the path of travel of the transfer unit  220 . Each of the first drop units  210  includes a plurality of drop nozzles  212 . The first drop nozzles  212  are formed at the first drop unit  210  such that the first drop nozzles  212  face the substrate  10  and a distance between the drop nozzles  212  is in a range from a few μm to hundreds of μm. 
   An organic material providing unit  500  includes an organic material containing tank  510  and a pipe  520  through which the organic material in the organic material containing tank  510  is provided to the drop nozzles  212 . The organic material providing unit  500  may further include an MFC for controlling an amount of the organic material that flows through the pipe  520 . The organic material providing unit  500  provides both of the first and second drop apparatuses  200  and  300  with the organic material. 
   The first transfer unit  220  transfers the first drop unit  210  in a predetermined direction. Preferably, the first transfer unit  220  linearly moves the first drop unit  210 . When the first drop unit  210  arrives at a predetermined position, the first transfer unit  220  stops operating. A distance between the first drop nozzles  212  is a few μm to hundreds of μm. To control the position of the first drop nozzles  212  more accurately, a first position adjusting unit  230  is disposed at the first drop unit  210 . The first position adjusting unit  230  is disposed between the first transfer unit  220  and the first drop unit  210 , so that the first position adjusting unit  230  moves with the first transfer unit  220 . The first position adjusting unit  230  moves the first drop unit  210  along the direction of travel of the first transfer unit  220 . The first position adjusting unit  230  may employ a device which reciprocates movement of the first drop unit  210 . 
   The second drop apparatus  300  includes a second drop unit  310 , a second transfer unit  320  and a second position adjusting unit  330 . The second drop unit  310  drops the organic material, for example, an organic light emitting material, a composition of color filter, etc., toward the substrate  10 . Then, organic patterns  20  are formed on the substrate  10 . The apparatus  100  of dropping the organic material includes at least one second drop unit  310 . In the present embodiment, the apparatus  100  of dropping the organic material includes a plurality of the second drop units  310 . 
   The second drop units  310  are also arranged side-by-side along the path of travel of the transfer unit  220 . The second drop units  310  are arranged similarly as the first drop units  210 . 
   Each of the second drop units  310  includes a plurality of second drop nozzles  312 . The second drop nozzles  312  are formed at the second drop units  310  such that the second drop nozzles  312  face the substrate  10 . The second display nozzles  312  are spaced apart from each other. A distance between the second display nozzles  312  is in a range from about a few μm to about hundreds μm. 
   The arrangement of first drop nozzles  212  and the second drop nozzles  312  is such that the first drop nozzles  212  are arranged along a first line, and the second drop nozzles  312  are arranged along a second line that is substantially parallel with the first line. Therefore, the first drop nozzles  212  and the second drop nozzles  312  drop droplets of the organic material onto different rows or columns of the array. Further, the first drop nozzles  212  and the second nozzles  312  can be arranged in a zigzag order wherein a first drop nozzle is positioned between the second nozzles or a second nozzle is positioned in between the first nozzles. 
   The organic material providing unit  500  provides also the second drop unit  310  with the organic material. 
   The second transfer unit  320  transfers the second drop unit  310  in a predetermined direction. The first and second transfer units  220  and  320  can be independently operated. To better control the position of the second drop nozzles  312 , a second position adjusting unit  330  is disposed at the second drop unit  310 . The second position adjusting unit  330  is disposed between the second transfer unit  320  and the second drop unit  310 , so that the second position adjusting unit  330  moves with the second transfer unit  320 . 
   The second position adjusting unit  330  moves the second drop unit  310  along the path of movement of the second transfer unit  320 . The second position adjusting unit  330  may employ an apparatus that reciprocates the second drop unit  310 . 
   Having described the exemplary embodiments of the present invention and its advantages, it is noted that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by appended claims.