Abstract:
A multiple vacuum evaporation coating device and a method for controlling the same. The vacuum evaporation coating device includes a plurality of evaporation sources, a rotating part adapted to rotate the plurality of evaporation sources and a coating block plate adapted to block all but one of said plurality of evaporation sources at any time, each of the plurality of evaporation sources comprise a case, a melting pot arranged within said case, an evaporation material arranged within the melting pot, a heating device arranged outside the melting pot and adapted to heat and evaporate the evaporation material, and a cooling device adapted to block heat generated by the heating device from transferring to an outside.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS AND CLAIM OF PRIORITY 
     This application is a divisional of Applicant&#39;s Ser. No. 11/370,033, now U.S. Pat. No. 8,025,735, and entitled MULTIPLE VACUUM EVAPORATION COATING DEVICE AND METHOD FOR CONTROLLING THE SAME filed in the U.S. Patent &amp; Trademark Office on 8 Mar. 2006 and issued on 27 Sep. 2011, and assigned to the assignee of the above-captioned application. Furthermore, this application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119, §120 and/or §121 from the aforesaid U.S. Pat. No. 8,025,735 and from an application for DEVICE AND METHOD FOR VACUUM PLATING BY MULTIPLE EVAPORATION earlier filed in Korean Intellectual Property Office on 9 Mar. 2005 and there duly assigned Ser. No. 10-2005-0019645. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a multiple vacuum evaporation coating device and a method for controlling the same, and more particularly to, a device and a method having a cooling device blocking the spread of heat while being able to control the rotation angle of the evaporation devices. 
     2. Description of the Related Art 
     Generally, an organic light emitting diode (OLED) display device has an indium tin oxide (ITO) anode, a metal cathode and an organic thin film multi-layer between the anode and the cathode. The organic thin film multi-layer can also have an ETL (Electron Transport Layer), an HTL (Hole Transport Layer) and an EML (Emitting Layer). The organic thin film multi-layer can also have an EIL (Electron Injecting Layer), an HIL (Hole Injecting Layer) or an HBL (Hole Blocking Layer) additionally inserted for the improvement of features of elements. 
     A typical OLED vacuum evaporation coating device used for forming organic thin film multi-layers generally performs the processes as follows. The first process is an ITO thin film evaporation coating process by vacuum evaporating several ITO thin film patterns on the surface of the glass substrate by sputtering. Then, as the prior process of ITO thin film, it is discharged so that the hole from ITO used for the positive pole can easily move to the emitting layer, and the surface is oxidized by using ultraviolet rays or a plasma. After that, in the organic thin film evaporation coating process, for example, by using the vacuum evaporation coating method in a high-degree vacuum state, the organic films are formed on the surface of the glass substrate. The structure of the vacuum chamber where these thin films are coated includes an evaporation source of materials, a sensor controlling the thickness of the film, a device aligning a glass substrate to the metal shadow masks, and a power source for evaporating materials. After the evaporation coating of these organic thin films is complete, the evaporation coating of metal electrodes, the evaporation coating of protective films, and the pack process are performed in order. 
     In this process, the evaporation coating device used in evaporation coating thin films is formed so that by heating organic and inorganic material, the material can be coated on a board installed inside the vacuum chamber. Various kinds of evaporation coating devices have been developed. The multiple vacuum evaporation coating device is used so that several evaporation sources can be rotated, and when the evaporation source is positioned at a location for heating, the melting pot is heated by a heating device. In this arrangement, the evaporation source is formed so that the melting pot having the evaporation materials can be heated by the heating device. The location for heating the melting pot includes a main heating position for evaporation coating and the preliminary heating position for heating the melting pot before being moved to the main heating position. 
     One drawback with this multiple evaporation coating device arrangement is that heat radiated from the melting pot was often transferred to the nearby melting pots, causing evaporation coating materials in the nearby the melting pots to discharge. Further, because the position of the main heating and the position of the preliminary heating were located far from each other, efficiency of preliminary heating was low. What is therefore needed is a multiple evaporation coating device that overcomes both these problems. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide an improved multiple evaporation coating device. 
     It is also an object of the present invention to provide a multiple evaporation coating device where heat generated in one of the devices does not warm up the other devices. 
     It is further an object of the present invention to provide a multiple evaporation coating device to have improved preliminary heating efficiency. 
     It is yet an object of the present invention to provide an improved method of operating a multiple evaporation coating device. 
     It is still an object of the present invention to provide a multiple vacuum evaporation coating device and a method for controlling the same that can prevent the transfer of heat generated to the nearby evaporation sources by installing a reflector blocking and cooling the heat generated from the heating device and the melting pot and a cooling device having low-temperature water on the evaporation source while improving upon the efficiency of the preliminary heating by controlling the rotation of the evaporation source and locating the position for main heating close to the location of the preliminary heating. 
     These and other object can be achieved by a vacuum evaporation device that includes a plurality of evaporation sources, a rotating part adapted to rotate the plurality of evaporation sources, and a coating block plate adapted to block all but one of said plurality of evaporation sources at any time, each of the plurality of evaporation sources comprise a case, a melting pot arranged within said case, an evaporation material arranged within the melting pot, a heating device arranged outside the melting pot and adapted to heat and evaporate the evaporation material, and a cooling device adapted to block heat generated by the heating device from transferring to an outside. 
     The cooling device can include at least one reflector, the at least one reflector being adapted to cover the heating device. The case can have a dual structure that includes an inner wall, outer wall and a closed space between the inner wall and the outer wall, the case being adapted to supply and discharge cooling water into and out of the closed space. 
     The vacuum evaporation device can further include upper and lower blocking parts arranged at upper and lower portions of the inner and the outer walls respectively, the upper and the lower blocking parts being adapted to close off the closed space. The supply pipe and the discharge pipe can be arranged at upper and the lower parts respectively of the outer wall. The vacuum evaporation device can further include a bulkhead arranged within the closed space and adapted to isolate the supply pipe from the discharge pipe, the bulkhead being arranged near each of the supply pipe and the discharge pipe. 
     The supply pipe and the discharge pipe can be arranged at the lower and the upper parts respectively of the outer wall, and the supply pipe and the discharge pipe can be arranged to be symmetric with each other about the case. The vacuum evaporation device can further include at least one cooling inductive pipe arranged between the supply pipe and the discharge pipe within the closed spaced. The vacuum evaporation coating device can further include a cooling cover that is adapted to block an upper part of the cooling source opened between the melting pot and the case, the cooling cover being supported by the case and extending to the melting pot. The rotating part can be adapted to rotate the plurality of evaporation sources, each heating device can include a first heating device adapted to heat adapted for a main heating for evaporation and a second heating device adapted for a preliminary heating. 
     According to another aspect of the present invention, a method of operating a vacuum evaporation coating device can include providing an evaporation coating device comprising a plurality of evaporation sources; a rotating part adapted to rotate the plurality of evaporation sources; and a coating block plate adapted to block all but one of said plurality of evaporation sources at any time, each of the plurality of evaporation sources comprise a case, a melting pot arranged within said case, an evaporation material arranged within the melting pot, a heating device arranged outside the melting pot and adapted to heat and evaporate the evaporation material, and a cooling device adapted to block heat generated by the heating device from transferring to an outside, heating said one of said plurality of evaporation sources not blocked by said coating block plate while preliminarily heating an adjacent one of said plurality of evaporation sources, rotating the plurality of evaporation sources by an angle θ so that said adjacent one of said plurality of evaporation sources is no longer blocked by said coating block plate, said angle θ being equal to =360°×((t−1)/s) where t and s satisfy 0&lt;((t−1)/s)≦1.0 and where s is the total number of evaporation sources, t is a natural number, and 360° is the angle acquired when n th  evaporation is rotated one time. s can be ≧2. T and s can satisfy the inequality 1&lt;t≦s. Among the evaporation sources, the n th  evaporation source is heated by the first heating device, and wherein the (n−1) th  evaporation source is heated by the second heating device. 
     According to still another aspect of the present invention, an evaporation coating device can include a plurality of evaporation sources, a rotating part adapted to rotate the plurality of evaporation sources and a coating block plate adapted to block all but one of said plurality of evaporation sources at any time, each of the plurality of evaporation sources comprise a case, a melting pot arranged within said case, an evaporation material arranged within the melting pot, a heating device arranged outside the melting pot and adapted to heat and evaporate the evaporation material, and a cooling device arranged outside the heating device and adapted to prevent heat generated by the heating device from passing therethrough. 
     The cooling device can include at least one reflector adapted to reflect heat generated by the heating device and traveling in a direction of the cooling device. The cooling device can include a first reflector and a second reflector arranged at an outside of the first reflector, each of the first reflector and the second reflector being adapted to reflect heat generated by the heating device and traveling in a direction of the cooling device. The cooling device can include a closed space filled with cooling water and arranged outside of the heating device. The cooling device can include a water supply pipe and a water discharge pipe connected to the closed space and adapted to deliver and remove cooling water from the closed space. 
    
    
     
       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 sectional view roughly illustrating the vacuum evaporation coating device having multiple evaporation sources according to an embodiment of the present invention; 
         FIG. 2  is an enlarged sectional view illustrating one of the evaporation sources of the vacuum evaporation coating device illustrated in  FIG. 1 ; 
         FIGS. 3 through 5  are variations of cooling devices of the evaporations sources of  FIG. 2 ; 
         FIG. 6  is a plane figure of the evaporation coating device illustrated in  FIG. 1 ; and 
         FIG. 7  illustrates a rotated state of the evaporation coating device of  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Turning now to the figures,  FIG. 1  is a sectional view roughly illustrating the vacuum evaporation coating device  100  having multiple evaporation sources  110  according to an embodiment of the present invention. Referring to  FIG. 1 , a board  20  is installed in a vacuum chamber  10 , and a evaporation coating device  100  is installed on the vacuum chamber  10  to allow for the evaporation coating of the evaporation coating materials. The evaporation coating device  100  includes several evaporation sources  110 , a rotating part  120  on which the several evaporation sources  110  are mounted, a fixed housing  130  fixed to the vacuum chamber  10  allowing the rotating part  120  to rotate, and a power source part  140 . 
     The evaporation sources  110  are arranged so that they can rotate 360° and so each evaporation source  110  forms the same angle with each other. In the rotating part  120  are several bearings  122  used for rotation, and a vacuum sealing should be present to prevent damage to the vacuum state of the rotating part  120 . 
     An evaporation coating blocking plate  132  is installed on the upper part of the fixed housing  130  so that evaporation coating materials discharged from non main heating evaporation sources  110  can be blocked. The evaporation coating blocking plate  132  forms an opening having a certain angle so that only the one evaporation source currently being subject to the main heating can discharge material into the vacuum chamber  10 . The evaporation coating blocking plate is fixed at the fixed housing  130 . 
     Turning now to  FIG. 2 ,  FIG. 2  is an enlarged sectional view illustrating one of the evaporation sources  110  of  FIG. 1 . Referring to  FIG. 2 , an evaporation source  110  includes a melting pot  111 , a heating device  112  located at the outer side of the melting pot  111  for heating the melting pot  111 , a power terminal  113  for connecting the heating device  112  to the power source part  140 , a case  114  where the power terminal  113  is installed, and a cooling device preventing heat generated by the melting pot  111  and the heating device  112  from being transferred to the outside. 
     The cooling device includes a reflector  150  covering the heating device  112  in order to block the heat from the heating device  112  and the melting pot  111  from escaping. The cooling device also includes a closed space  160  having an inflow and an outflow for the cooling water  162 , the closed space  160  and the cooling water  162  being within case  114  between inner wall  114   a  and outer wall  114   b.    
     The reflector  150  is preferably made up of several units, including first reflector  150   a  that reflects the high-temperature heat emanating from the heating device  112  and from the melting pot  111 . First reflector  150   a  is located near the heating device  112 . Reflector  150  also includes second reflector  150  that also reflects high-temperature heat that transmits through the first reflector  150   a.    
     The first and second reflectors  150   a  and  150   b  are preferably formed to having some space between each other. Further, the first and second reflectors  150   a  and  150   b  are preferably located in a space between the heating device  112  and the inner wall  114   a  of case  114 . Reflector  150  serves to prevent the unwanted transfer of heat to an outside of the evaporation source. 
     Closed space  160  is preferably sealed by installing blocking materials  114   c  on the upper and the lower parts of the inner wall  114   a  and the outer wall  114   b . Blocking materials  114   c  can be sealed to the inner wall  114   a  and the outer wall  114   b  of the case  114 . Case  114  has the dual wall structure, and within this dual structure is the closed space  160 . 
     A supply pipe  164  and a discharge pipe  166  are installed at the lower part and the upper part respectively of the outer wall  114   b . Supply pipe  164  and discharge pipe  166  are connected to the closed space  160  so that the cooling water  162  can be supplied to and removed from the closed space  160 . It is preferable that the supply pipe  164  is connected to the supply water tank (not shown) located outside, and a separate pump (not shown) is arranged for supplying the cooling water  162  to the closed space  160  via the supply pipe  164 . The discharge pipe  166  is also preferably connected to the discharge water tank (not shown). Another pump (not shown) can be installed to remove cooling water  162  from closed space  160  to the tank via the discharge pipe  166 . 
     A cooling cover  170  is also included to block heat escaping from the upper end of the evaporating source  110  at the opening between the upper side of the melting pot  111  and the inner wall  114   a . The cooling cover  170  is preferably extended to the end part of the melting pot  111  and is supported by the upper blocking materials  114   c . The cooling cover  170  can be made of the same material as the reflector  150 , or can be made of some other insulating material. 
     Turning now to  FIGS. 3 through 5 ,  FIGS. 3 through 5  illustrate variations of the cooling device of  FIG. 2 . Referring to  FIG. 3 , a bulkhead  180  is arranged within closed space  160  so that the supply pipe  164  and the discharge pipe  166  can be further separated from each other. The supply pipe  164  and the discharge pipe  166  are preferably located on opposite sides of the bulkhead  180 . This structure allows water supplied by supply pipe  164  to become heated before being discharged from the closed space  160  by discharge pipe  166 . 
     Referring now to  FIG. 4 , the supply pipe  164  and the discharge pipe  166  are located at opposite sides of case  114  diametrically opposite from each other. The purpose of this arrangement of  FIG. 4  is to discharge the cooling water  162  via discharge pipe  166  only after the cooling water  162  has had a chance to sufficiently move throughout the closed space  160  after being supplied by the supply pipe  164 . 
     Referring now to  FIG. 5 , the cooling device further includes one or more inductive pipes  190  arranged within the closed space  160 . In  FIG. 5 , it is preferable that more than one inductive pipe  190  is used so that the range of the heat absorption can be reduced. Preferably, the inductive pipes  190  are arranged so that one end is located at an upper end of closed space  160  and is attached to a discharge pipe  166  while the other end of each inductive pipe  190  is located at a lower end of the closed space  160  and is attached to a supply pipe  164 . 
     Turning now to  FIGS. 6 and 7 , the control method of the vacuum evaporation coating device having multiple evaporation sources vis a vis the evaporation coating blocking plate  132  and the main and the preliminary heaters is illustrated.  FIG. 6  is the plane figure of the evaporation coating device illustrated in  FIG. 1 , and  FIG. 7  is the plane figure illustrating the state in which the evaporation source of  FIG. 6  moved to the next process.  FIG. 6  shows the initial position and  FIG. 7  shows the position of the evaporation sources after being rotated one position. 
     Referring to  FIG. 6 , several evaporation sources  110  with cooling devices within are arranged so that they can rotate 360° by rotating part  120 . The rotating part  120  is attached to the evaporation sources  110  and to the power source part  140  that provides rotating power to the rotating part  120 . A control part measures and controls the rotation angle of the rotating part  120  by the rotating power of the power source part  140 . The rotating part  120  is a device generally installed in the rotation-type evaporation coating device  100 , and the detailed explanations are omitted here. 
     An evaporation coating blocking plate  132  allows for the discharge of only the evaporation source  110   a  being heated by the main heating, and blocks the discharge of the other remaining evaporation coating sources  100   b ,  100   c , . . . ,. Thus it is only the evaporation coating materials of the evaporation source  110   a  heated by the main heating device  200  that is allowed to coat the board  20  of  FIG. 1 . 
     The location where the evaporation source  110   a  is heated by the first (main) heating device  200  and the location where the evaporation source  110   b  is heated by the second (preliminary) source  210  are set. The first and second heating devices  200 ,  210  are arranged close each other as in  FIGS. 6 and 7 . 
     As illustrated in  FIG. 6 , the first evaporation source  110   a  is heated by the first (main) heating device  200  to allow for evaporation coating. At a location near the evaporation source heated by the main heating  110   a  is the second evaporation source  110   b  that is heated by the second (preliminary) heating device  210 . In this way, one process completed. 
     In other words, the n th  evaporation source  110   a  among several evaporation sources having cooling devices is heated by the first (main) heating device  200 , and the (n−1) th  evaporation source  110   b  waits for the main heating while being heated by the second (preliminary) heating device  210 . When the evaporation coating of n th  evaporation source  110   a  heated by the main heating device  200  is completed, the (n−1) th  evaporation source  110   b  heated by the preliminary heating device  210  is moved to the main heating location so that it can be heated by the first (main) heating device  200  as in  FIG. 7 . As this occurs, the (n−2) th  evaporation source  110   c  of  FIG. 6  is moved to the location of the preliminary heating device  210  in  FIG. 7 . Thus,  FIG. 7  illustrates the result of one incremental rotation of rotating part  120 . 
     When one process of the evaporation source  110  is completed, if the rotation of the evaporation source  110  is expressed by Equation 1, the rotation angle θ rotated by the rotating device for one process can be expressed as follows where s is the total number of evaporation sources, and 360° is the angle when n th  evaporation source is rotated one time:
 
θ=360°×(( t− 1)/ s )  [Equation 1]
 
     Here, the equation 1 should satisfy 0&lt;(t−1)/s≦1.0. 
     Where s, the total number of evaporation sources should satisfy s≧2. 
     And t, a natural number should satisfy 1&lt;t≦s. 
     Likewise, the reason why the location of the main heating and the location of the preliminary heating should be close each other is because the high-temperature heat discharged from the evaporation sources  110   a  and  110   b  can be blocked and cooled off by installing a cooling device for each evaporation source  110 . 
     According the present invention described above, because the high-temperature heat generated from the evaporation sources heated by the main and the preliminary heating is prevented from being transferred to nearby evaporation sources, the discharge of the evaporation coating materials by heating evaporation sources except at the evaporation source heated by the main heating is significantly reduced. Also, since the location of the main heating and the location of the preliminary heating are close to each other, there is an increase in the efficiency in the utilization of the preliminary heating device according to its original purpose. 
     Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes might be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.