Abstract:
The invention provides a vacuum evaporation device, belongs to the field of vacuum evaporation and can solve the problem of non-uniform thickness of a coating film formed by an existing vacuum evaporation device. The vacuum evaporation device provided by the present invention comprises an evaporation chamber, at least one evaporation source device disposed in the evaporation chamber, and a baffle assembly disposed between the evaporation source device and a substrate to be evaporated. The evaporation source device is disposed within the center region of a base plate of the evaporation chamber. The baffle assembly is provided with a baffle assembly opening used for allowing evaporation substances to pass therethrough and corresponding to the position of the evaporation source device. As the evaporation source device is disposed within the center region of the evaporation chamber, the thickness of a coating film formed on the surface of the substrate is more uniform.

Description:
FIELD OF THE INVENTION  
       [0001]    The present invention relates to the technical field of vacuum evaporation, and particularly relates to a vacuum evaporation device. 
       BACKGROUND OF THE INVENTION 
       [0002]    As shown in  FIG. 1 , a vacuum evaporation device in the prior art includes an evaporation chamber  5  and a base plate  1  located at the lower part of the evaporation chamber  5 . A substrate  4  to be evaporated is placed at the upper part of the evaporation chamber  5 . An evaporation source device  10  is provided at the edge part of the base plate  1 . A baffle  3  is provided at the middle part of the evaporation chamber  5 . A baffle opening  31  is formed in the baffle  3 , and the position of the baffle opening  31  corresponds to the position of the evaporation source device  10 . During evaporation, the evaporation substance evaporated out from the evaporation source device  10  is evaporated on the surface of the substrate  4  through the baffle opening  31 . 
         [0003]    As shown in  FIG. 2 , each baffle opening  31  is provided with a baffle opening cover plate  32  capable of moving (or rotating) and covering the baffle opening  31 . The baffle opening cover plate  32  is used for occluding the baffle opening  31  when the evaporation source device  10  is at a preheated state, so that the evaporation substance evaporated out from the evaporation source device  10  is prevented from polluting the inner surface of the evaporation chamber  5 . 
         [0004]    However, as the baffle opening  31  is provided at the edge part of the base plate  1 , in accordance with the molecular diffusion free-path principle, this will result in non-uniform thickness distribution of a coating film evaporated on the surface of the substrate  4 , and the thickness of the coating film near the evaporation source device  10  is far greater than that of the coating film away from the evaporation source device. 
       SUMMARY OF THE INVENTION 
       [0005]    An objective of the present invention is to solve the problem of non-uniform thickness of a coating film formed by an existing vacuum evaporation device and provide a vacuum evaporation device capable of forming a coating film with uniform thickness. 
         [0006]    The technical solution employed to solve the technical problem of the present invention is to provide a vacuum evaporation device, including an evaporation chamber, at least one evaporation source device disposed in the evaporation chamber, and a baffle assembly disposed between the evaporation source device and a substrate to be evaporated, wherein the at least one evaporation source device is disposed within the center region of a base plate of the evaporation chamber; and 
         [0007]    the baffle assembly is provided with a baffle assembly opening used for allowing evaporation substances to pass therethrough and corresponding to the position of the at least one evaporation source device. 
         [0008]    In the vacuum evaporation device provided by the present invention, as the evaporation source device is disposed within the center region of the base plate of the evaporation chamber, the thickness of a coating film formed on the surface of the substrate is more uniform. 
         [0009]    Preferably, the size and/or shape of the baffle assembly opening are/is adjustable. 
         [0010]    Further preferably, the baffle assembly includes at least two baffles located at different positions in the height direction of the evaporation camber, each of the baffles being provided with an opening and being able to move along the horizontal direction, the baffle assembly opening being formed at the overlapped position of the openings of the baffles. 
         [0011]    Preferably, each evaporation source device includes at least two movable point evaporation sources, and the point evaporation sources can be moved to a position corresponding to the baffle assembly opening. 
         [0012]    Further preferably, each evaporation source device further includes a movable carriage for carrying the point evaporation sources. 
         [0013]    Further preferably, the carriage is disc-shaped and can rotate around its center, and the point evaporation sources are distributed at equal intervals along the circumference of the disc-shaped carriage. 
         [0014]    Preferably, there are three evaporation source devices, the carriages of the evaporation source devices are identical in diameter, and the circumference of each carriage is externally tangent to the circumferences of the other two carriages. 
         [0015]    Preferably, each of the carriages is strip-shaped, each evaporation source device further comprises a straight guide rail parallel to the strip-shaped carriage, and the strip-shaped carriage is able to move along the straight guide rail. 
         [0016]    Further preferably, there are multiple evaporation source devices, and the straight guide rails of the evaporation source devices are parallel to one another and arranged side by side. 
         [0017]    Further preferably, the point evaporation sources are arranged at equal intervals in the length direction of the strip-shaped carriages. 
         [0018]    As in the vacuum evaporation device provided by the present invention, the baffle assembly opening is located at the middle part of the evaporation chamber; the thickness of the coating film evaporated on the surface of the substrate is more uniform. 
         [0019]    Secondly, as there are multiple point evaporation sources, and the point evaporation sources can be moved under the baffle assembly opening alternately, the doped evaporation of two or more substances may be realized by selecting the point evaporation sources capable of evaporating out different evaporation substances. Meanwhile, the distance between the point evaporation sources during working is relatively small, so it is more approximate to single-point evaporation, and it is advantageous for the same proportion of doped components of the doped coating film. 
         [0020]    Finally, as the size of the baffle assembly opening is adjustable, the point evaporation sources for doped evaporation performs evaporation from the same baffle assembly opening, which is as small as possible, so that the doped components of the doped coating film formed on the surface of a substrate are in the same proportion. The same proportion of the doped components is of vital importance to the performance of the doped coating film, so the uniformity of the performance of the doped coating film on the whole surface of the substrate is ensured. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a schematic diagram of a longitudinal cross-section of a vacuum evaporation device in the prior art; 
           [0022]      FIG. 2  is a top view of a vacuum evaporation device in the prior art from a perspective of the inferior of a substrate; 
           [0023]      FIG. 3  is a schematic diagram of a longitudinal cross-section of a vacuum evaporation device in an embodiment of the present invention; 
           [0024]      FIG. 4  is a top view of a vacuum evaporation device with rotatable and movable point evaporation sources in an embodiment of the present invention from a perspective of the inferior of a substrate; and 
           [0025]      FIG. 5  is a top view of a vacuum evaporation device with straightly movable point evaporation sources in an embodiment of the present invention from a perspective of the inferior of a substrate; 
       
    
    
       [0026]    in the figures:  1 —Base plate;  3 —Baffle;  31 —Baffle opening;  32 —Baffle opening cover plate;  4 —Substrate;  5 —Evaporation chamber;  10 —Evaporation source device;  11 —Point evaporation source;  12 —Carriage;  20 —Baffle assembly;  200 —Baffle assembly opening;  21 —First baffle;  22 —Second baffle;  210 —First baffle opening; and,  220 —Second baffle opening. 
       DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0027]    To make those skilled in the art better understand the technical solutions of the present invention, the present invention will be further described below in details with reference to the accompanying drawings and specific implementations. 
       Embodiment 
       [0028]    As shown in  FIGS. 3-5 , this embodiment provides a vacuum evaporation device. 
         [0029]    As shown in  FIG. 3 , the vacuum evaporation device includes an evaporation chamber  5 , a base plate  1  disposed at the lower part of the evaporation chamber  5 , at least one evaporation source device  10  disposed within the center region of the base plate  1 , and a baffle assembly  20  disposed inside the evaporation chamber  5  and used for preventing evaporation substances from polluting the inner surface of the evaporation chamber  5 . The baffle assembly  20  is provided with a baffle assembly opening  200  corresponding to the position of the at least one evaporation source device  10 . The evaporation source device  10  is used for evaporating out evaporation substances. 
         [0030]    A substrate  4  to be evaporated is disposed at the upper part of the evaporation chamber  5 . The evaporation substances evaporated out from the at least one evaporation source device  10  are evaporated on the whole surface of the substrate  4  through the baffle assembly opening  200 . The size of the baffle assembly opening  200  is configured to be capable of preventing the evaporation substrates from polluting the inner surface of the evaporation chamber  5 . 
         [0031]    Preferably, the baffle assembly  20  includes at least two baffles located at different positions in the height direction of the evaporation chamber  5 . If the baffle assembly  20  includes two baffles, the two baffles are a first baffle  21  and a second baffle  22  respectively. The first baffle  21  has a first baffle opening  210 , and the second baffle  22  has a second baffle opening  220 . In this embodiment, the relative positions of the first baffle  21  and the second baffle  22  are not limited. That is, the first baffle  21  may be located above the second baffle  22  (as shown in  FIG. 3 ), or may be located under the second baffle  22 . 
         [0032]    As shown in  FIG. 3 , preferably, when the first baffle  21  and the second baffle  22  are moved in the horizontal direction, the baffle assembly opening  200  is formed at the overlapped position of the first baffle opening  210  and the second baffle opening  220 . Preferably, the shape of the baffle assembly opening  220  may be circular or oval, etc. The first baffle  21  and the second baffle  22  may be controlled to move separately in the horizontal direction by the transmission of a transmission rod or by electromagnetic transmission, so that the size and/or shape of the formed baffle assembly opening  200  are/is controlled. 
         [0033]    Preferably, the first baffle  21  and the second baffle  22  may also be composed of at least two parts respectively. The constituent parts of the first baffle  21  and the second baffle  22  may be controlled to move separately in the horizontal direction by the transmission of a transmission rod or by electromagnetic transmission, so that the size and/or shape of the formed baffle assembly opening  200  are/is controlled. 
         [0034]    As shown in  FIG. 4 , each of the evaporation source devices  10  (the portion blocked by the baffle assembly  20  in  FIG. 4  is represented with a dotted line) includes point evaporation sources  11  and a carriage  12  for carrying the point evaporation sources  11 . The carriage  12  may be rotated. Preferably, the carriage  12  is disc-shaped and may rotate around its center. The point evaporation sources  11  are distributed along the circumference of the disc-shaped carriage  12 . Preferably, the point evaporation sources  11  are distributed at equal intervals on the circumference of the disc-shaped carriage  12 , so that it is more convenient to control the disc-shaped carriage  12  to rotate by a motor so as to drive the point evaporation sources  11  to rotate. 
         [0035]    As shown in  FIG. 4 , three disc-shaped carriages  12  are provided within the center region of the base plate  1 , and the rotation speed and rotation direction of each of the disc-shaped carriages  12  may be controlled by a motor. Preferably, 7 point evaporation sources  11  are borne on each of the disc-shaped carriages  12 , and each of the point evaporation sources  11  has independently controlled heating and cooling devices. Doped evaporation or non-doped evaporation is realized by controlling the time sequence of the point evaporation sources  11 . 
         [0036]    Preferably, the three disc-shaped carriages  12  are identical in diameter, and the circumference of each of the disc-shaped carriages  12  is externally tangent to the circumferences of the other two disc-shaped carriages, so that three point evaporation sources  11  may be simultaneously exposed by a relatively small baffle assembly opening  200 , and the distance between the point evaporation sources  11  on each of the disc-shaped carriages  12  is closer. Accordingly, the evaporation substances evaporated out from the close point evaporation sources  11  are more approximately evaporated out from a single point, and it is advantageous for the same proportion of the doped components of a coating film on the surface of the substrate  4 . 
         [0037]    It may be understood that, the number of the evaporation source devices  10  may be determined according to specific application situations. The size of the baffle assembly opening  200  is related to the number of the point evaporation sources  11  to be evaporated. The size of the baffle assembly opening  200  may be adjusted to expose all the point evaporation sources  11  to be evaporated. By controlling the rotation speed of the disc-shaped carriages  12  and the preheating speed of the point evaporation sources  11 , the preheating of the next point evaporation source  11  to be evaporated is completed while the evaporation of the current point evaporation source  11  is finished, so that the evaporation source devices  10  may perform evaporation continuously, and the time of evaporation is thus saved. 
         [0038]    As shown in  FIG. 5 , each of the evaporation source devices  10  (the portion blocked by the baffle assembly  20  in  FIG. 5  is represented with a dotted line) includes point evaporation sources  11  and a strip-shaped carriage  12  for carrying the point evaporation sources  11 . The strip-shaped carriage  12  may be moved along the length direction thereof. For example, the strip-shaped carriage  12  may be moved on a straight guide rail (not shown because it is blocked by the strip-shaped carriage  12  in  FIG. 5 ), and the strip-shaped carriage  12  and the straight guide rail are arranged in parallel. 
         [0039]    Preferably, three strip-shaped carriages  12  are disposed on three parallel straight guide rails (blocked by the carriages  12 ). Preferably, the three strip-shaped carriages  12  are provided within the center region of the base plate  1 . The strip-shaped carriages may be controlled to make a linear motion along the straight rails by a motor, so that the point evaporation sources  11  to be evaporated are moved under the baffle assembly opening  200  for evaporation. Preferably, the point evaporation sources  11  are arranged at equal intervals in the length direction of the strip-shaped carriages  12 , so that it is more convenient to control the strip-shaped carriages  12  to make a linear motion along the straight guide rails by a motor so as to drive the point evaporation sources  11  to make a linear motion. 
         [0040]    It may be understood that, the number of the straight guide rails may be determined according to specific application situations. The size of the baffle assembly opening  200  is related to the number of the point evaporation sources  11  to be evaporated. The size of the baffle assembly opening  200  may be adjusted to expose all the point evaporation sources  11  to be evaporated. By controlling the moving speed of the strip-shaped carriages  12  and the preheating speed of the point evaporation sources  11 , the preheating of the next point evaporation source  11  to be evaporated is completed while the evaporation of the current point evaporation source  11  is finished, so that the evaporation source devices  10  may perform evaporation continuously, and the time of evaporation is thus saved. 
         [0041]    The usage methods of the above vacuum evaporation devices of different structures are similar. The single evaporation of a single point evaporation source  11  on a single evaporation source device  10  may be realized, as long as there is an evaporation source device  10  with a single point evaporation source  11 . Correspondingly, the baffle assembly opening  200  may become smaller by moving the baffles in the horizontal direction. The simultaneous evaporation or alternate evaporation of multiple point evaporation sources  11  on a single evaporation source device  10  may also be realized, as long as there is an evaporation source device  10  with multiple point evaporation sources  11 . The simultaneous evaporation or alternate evaporation of single point evaporation sources  11  on multiple evaporation source devices  10  may also be realized, as long as there are multiple evaporation source devices  10  and single evaporation sources  11  respectively disposed on each of the evaporation source devices  10 . The simultaneous evaporation or alternate evaporation of multiple point evaporation sources  11  on multiple evaporation source devices  10  may also be realized, as long as there are multiple evaporation source devices  10  and multiple point evaporation sources  11  disposed on each of the evaporation source devices  10 . Correspondingly, the size and/or shape of the baffle assembly opening  200  may be adjusted by moving the baffles in the horizontal direction. It may be understood that those skilled in the art may adjust the usage methods of the vacuum evaporation device according to application situations. 
         [0042]    In the vacuum evaporation device provided by this embodiment, the baffle assembly opening is located at the middle part of the evaporation chamber, so the thickness of the coating film evaporated on the surface of the substrate is more uniform. Secondly, as there are multiple point evaporation sources, and the point evaporation sources are moved to be under the baffle assembly opening alternately, the doped evaporation of two or more substances may be realized by selecting the point evaporation sources capable of evaporating out different evaporation substances. Meanwhile, the distance between the point evaporation sources during working is relatively small, so they are more approximate to a single-point evaporation, and it is advantageous for the same proportion of doped components of the doped coating film. Finally, as the size of the baffle assembly opening is adjustable, the point evaporation sources for doped evaporation performs evaporation from the same baffle assembly opening, which is as small as possible, so that the doped components of the doped coating film formed on the surface of a substrate are in the same proportion. The same proportion of the doped components is of vital importance to the performance of the doped coating film, so the uniformity of the performance of the doped coating film on the whole surface of the substrate is ensured. 
         [0043]    It may be understood that, the forgoing implementations are merely exemplary implementations for describing the principle of the present invention, but the present invention is not limited thereto. A person of ordinary skill in the art may make various variations and improvements without departing from the spirit and essence of the present invention, and these variations and improvements are also deemed as falling into the protection scope of the present invention.