Abstract:
The present invention provides an OLED display motherboard, a packaging method thereof and a packaging system, belongs to the field of organic light-emitting display technology, and can solve the problem of poor sealing performance in the existing OLED display motherboard. The OLED display motherboard of the present invention comprises a package cover plate and an OLED substrate, which are assembled with each other in an aligned manner, a sealant is provided between the package cover plate and the OLED substrate, and the sealant is disposed in a peripheral region of the OLED display motherboard, and includes a hot melt adhesive.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention belongs to the field of organic light-emitting display technology, and particularly relates to an OLED display motherboard, a packaging method thereof and a packaging system. 
       BACKGROUND OF THE INVENTION 
       [0002]    An organic light-emitting diode (OLED) display device, as a new flat panel display device, has drawn more and more attention, and becomes a next-generation display technology that might replace liquid crystal display, due to its characteristics such as active light emission, high luminance, wide viewing angle, quick response, low power consumption, flexibility, and the like. 
         [0003]    In an existing OLED device, there is an organic layer material that is extremely sensitive to water vapor and oxygen, and thus the service life of the OLED device is greatly reduced. In order to solve this problem, generally in the prior art, the organic layer material of the OLED device is isolated from the outside with various materials, so that the tightness meets the following criteria: the amount of water vapor is smaller than 10 −6 g/m 2  per day, and the amount of oxygen is smaller than 10 −3 cm 3 /m 2  per day. In the prior art, the main sealing method includes: placing an OLED substrate including a plurality of display regions on an operating platform of a bonding machine; coating a UV adhesive on the peripheral region of a package cover plate to be bonded with the OLED substrate; coating frit on the package regions around the display regions on the OLED substrate; then, vacuumizing an environment, in which the bonding machine is located, bonding the package cover plate with the OLED substrate to form an OLED display motherboard; after the bonding, introducing nitrogen into the environment to release the vacuum state of the environment, and then placing the bonded package cover plate and OLED substrate in the atmospheric environment. At this time, the peripheral region of the package cover plate is irradiated with a UV lamp so that the UV adhesive in that region is cured. Subsequently, a laser is emitted towards positions with the frit provided, so that the OLED substrate of the OLED panel corresponding to each display region and the package substrate are bonded, and thereafter, cutting the OLED display motherboard according to the respective package regions to form the OLED panels. 
         [0004]    Inventor(s) found that at least the following problem exists in the prior art: before irradiating the peripheral region of the package cover plate with a UV lamp, since there is a pressure difference between the UV adhesive in the cell and the UV adhesive in the atmospheric environment, the UV adhesive in that region is likely to be “penetrated” to allow the gases to enter into the cell from the outside, and at this time, the frit has not been cured yet, so the OLED device may be contaminated. 
       SUMMARY OF THE INVENTION 
       [0005]    In view of the above problem in sealing of the existing OLED display motherboard, the present invention provides an OLED display motherboard with good sealing performance, a packaging method thereof and a packaging system, 
         [0006]    The technical solution adopted to solve the technical problem of the present invention is an OLED display motherboard, comprising a package cover plate and an OLED substrate assembled with each other in an aligned manner, a sealant is provided between the package cover plate and the OLED substrate, and the sealant is disposed in a peripheral region of the OLED display motherboard, and includes a hot melt adhesive. 
         [0007]    Preferably, the hot melt adhesive is any one of EVA hot melt adhesive, polyester-based hot melt adhesive, and hot melt sealing adhesive. 
         [0008]    Preferably, middle region of the OLED display motherboard is provided with a plurality of display regions and package regions around the display regions, and a frame-sealant is provided at positions, corresponding to the package regions, between the package cover plate and the OLED substrate. 
         [0009]    Further preferably, the material of the frame-sealant includes frit. 
         [0010]    The technical solution adopted to solve the technical problem of the present invention is a packaging system comprising a sealant coating device which comprises: a first bearing platform, configured for bearing a package cover plate; and a coating mechanism, configured for coating a sealant in a peripheral region of the package cover plate, and the sealant includes a hot melt adhesive. 
         [0011]    Preferably, the coating mechanism comprises a collecting unit, a tray, a plurality of fixing columns provided on the tray and a driver. The collecting unit is configured for collecting positional relationship between the respective fixing columns and reference points on the package cover plate to be subjected to coating. The driver is configured for, based on the positional relationship between the fixing columns and the reference points on the package cover plate to be subjected to coating collected by the collecting unit, adjusting each fixing column in an initial active region corresponding thereto on the tray, and driving each fixing column to coat the hot melt adhesive in the peripheral region of the package cover plate. 
         [0012]    Further preferably, the collecting unit comprises a plurality of cameras in one-to-one correspondence with the plurality of fixing columns, and each camera is fixed to one fixing column corresponding thereto. 
         [0013]    Further preferably, one end of each fixing column close to the first bearing platform is provided with a heating head, which is configured for preheating at least part of the hot melt adhesive after the hot melt adhesive is coated in the peripheral region of the package cover plate. 
         [0014]    Further preferably, the number of the fixing columns is four, and the four fixing columns are disposed at four corners of the tray, respectively. 
         [0015]    Preferably, the packaging system further comprises a bonding device which comprises: a second bearing platform configured for bearing an OLED display motherboard; and a heating unit configured for heating the peripheral region of the package cover plate after the OLED display motherboard is formed by assembling the package cover plate and an OLED substrate in an aligned manner. 
         [0016]    Further preferably, the heating unit is made of electrical resistance heating strip. 
         [0017]    Further preferably, the bonding device further comprises a pressing unit which is configured for pressing the peripheral region of the OLED display motherboard after the OLED display motherboard is formed by assembling the package cover plate and the OLED substrate in an aligned manner. 
         [0018]    Further preferably, the pressing unit is made of flexible material. 
         [0019]    The technical solution adopted to solve the technical problem of the present invention is a packaging method of an OLED display motherboard, comprising steps of coating a hat melt adhesive in a peripheral region of a package cover plate;
       assembling the package cover plate subjected to the above step and an OLED substrate in an aligned manner to form the OLED display motherboard; and heating a peripheral region of the OLED display motherboard to seal the package cover plate and the OLED substrate.       
 
         [0021]    Preferably, the step of coating a hot melt adhesive in the peripheral region of a package cover plate comprises: determining positions of a plurality of reference points in the peripheral region of the package cover plate, determining positional relationship between the plurality of reference points and an area to be coated with the hot melt adhesive, and coating the hot melt adhesive in the peripheral region of the package cover plate. 
         [0022]    Preferably, before the step of assembling the package cover plate and the OLED substrate in an aligned manner, the packaging method further comprises: preheating an area where the plurality of reference points are located in the package cover plate with the hot melt adhesive coated in the peripheral region thereof, so as to pre-bond the hot melt adhesive and the package cover plate. 
         [0023]    In the packaging method, the number of the plurality of reference points may be four. 
         [0024]    In the packaging method, the heating temperature for preheating the area where the plurality of reference points are located may be in a range of 95±5° C. 
         [0025]    Preferably, the heating temperature for heating the peripheral region of the OLED display motherboard is in a range of 95±5° C. 
         [0026]    Preferably, after the step of heating the peripheral region of the OLED display motherboard, the packaging method further comprises: pressing, by a pressing unit, the peripheral region of the OLED display motherboard. 
         [0027]    In the OLED display motherboard according to the embodiment of the present invention, the package cover plate and the OLED substrate are sealed by the hot melt adhesive, so that the OLED display motherboard formed by assembling the both in an aligned manner has better sealing performance. 
         [0028]    In the packaging method according to the embodiment of the present invention, the package cover plate and the OLED substrate of the OLED display motherboard are sealed with the hot melt adhesive, and as compared to the UV adhesive, the hot melt adhesive is of low cost, has a simple arrangement process, and is easy to implement, and no curing process is needed for the hot melt adhesive after the package cover plate and the OLED substrate are assembled in an aligned manner, therefore, the cost can be saved and production efficiency can be improved. 
         [0029]    The packaging system according to the embodiment of the present invention has a simple structure, and can perfectly seal the package cover plate and the OLED substrate, and thus the OLED display motherboard formed after sealing has better performance. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]      FIG. 1  is a schematic diagram of a package cover plate of an OLED display motherboard in an embodiment of the present invention. 
           [0031]      FIG. 2  is a schematic diagram of an OLED substrate of an OLED display motherboard in an embodiment of the present invention. 
           [0032]      FIG. 3  is a schematic diagram of a sealant coating device in a packaging system in an embodiment of the present invention. 
           [0033]      FIG. 4  is a schematic diagram of a coating mechanism in the sealant coating device shown in  FIG. 3 . 
           [0034]      FIG. 5  is a bonding device in a packaging system in an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0035]    To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and the specific implementations. 
         [0036]    Referring to  FIGS. 1 and 2 , one embodiment of the present invention provides an OLED display motherboard, which includes a package cover plate  10  and an OLED substrate  20 , assembled with each other in an aligned manner. A sealant is provided between the package cover plate  10  and the OLED substrate  20 , and the sealant is disposed in the peripheral region of the OLED display motherboard, and includes a hot melt adhesive  11 . 
         [0037]    In the peripheral region of the OLED display motherboard of this embodiment, since the space between the package cover plate  10  and the OLED substrate  20  is sealed by the hot melt adhesive  11  which itself has a better adhesion property as compared with the UV adhesive, the package cover plate  10  and the OLED substrate  20  can be well sealed, particles and impurities in the external environment can be effectively prevented from entering into the interior of the OLED display motherboard to contaminate the devices inside the OLED display motherboard, and thus the problem of low bonding yield of the OLED display motherboard can be improved. 
         [0038]    For example, the hot melt adhesive  11  in this embodiment is any one of EVA (ethylene and vinyl acetate copolymer) hot melt adhesive, polyester-based hot melt adhesive, and hot melt sealing adhesive. Needless to say, the hot melt adhesive  11  in this embodiment is not limited thereto, and may also be other hot melt adhesive similar thereto, which is not elaborated here. 
         [0039]    In this embodiment, the middle region of the OLED display motherboard is provided with a plurality of display regions  21  and package regions  22  around the display regions. A frame-sealant is provided at positions, corresponding to the package regions  22 , between the package cover plate  10  and the OLED substrate  20 . For example, the material of the frame-sealant is frit. 
         [0040]    In the OLED display motherboard of this embodiment, the package cover plate  10  and the OLED substrate  20  are sealed by the hot melt adhesive  11 , so the OLED display motherboard formed by assembling both in an aligned manner has better sealing performance. 
         [0041]    Referring to  FIGS. 3 and 4 , another embodiment of the present invention provides a packaging system, which includes a sealant coating device. The sealant coating device includes: a first bearing platform  30 , configured for bearing the package cover plate and a coating mechanism  40 , configured for coating the hot melt adhesive  11  in the peripheral region of the package cover plate  10 . 
         [0042]    In this embodiment, the sealant coating device included in the packaging system achieves a better tightness when assembling the package cover plate  10  and the OLED substrate  20  in an aligned manner, by coating the hat melt adhesive  11  in the peripheral region of the package cover plate  10 . 
         [0043]    For example, the coating mechanism  40  of this embodiment includes a collecting unit  43 , a tray  41 , a plurality of fixing columns  42  provided on the tray  41  and a driver (not shown). The collecting unit  43  is configured for collecting positional relationship between the respective fixing columns  42  and reference points on the package cover plate  10  to be subjected to coating. The driver is configured for, based on the positional relationship between the fixing columns  42  and the reference points on the package cover plate  10  to be subjected to coating collected by the collecting unit  43 , adjusting each fixing column  42  in an initial active region (which refers to a region in which the fixing column  42  is allowed to move to adjust the initial position of the fixing column  42  on the tray to an initial position properly corresponding to the reference point, for example, the area A defined by a circle shown in the figure) corresponding thereto on the tray  41  so as to position the fixing column  42  at a suitable initial position, and for driving each fixing column  42  to coat the hot melt adhesive  11  in the peripheral region of the package cover plate  10 . 
         [0044]    For example, the collecting unit  43  of this embodiment includes a plurality of cameras in one-to-one correspondence with the plurality of fixing columns  42 , and each camera is fixed to one fixing column  42  corresponding thereto. One end of each fixing column  42  close to the first bearing platform  30  is provided with a heating head  44 , which is configured for heating at least part of the hot melt adhesive  11  after coating the hot melt adhesive  11  in the peripheral region of the package cover plate  10 , so as to pre-bond the hot melt adhesive  11  and the peripheral region of the package cover plate  10 . For example, the number of the fixing columns  42  is four, the four fixing columns  42  are disposed at four corners of the tray  41 , respectively, and accordingly, the number of the cameras corresponding thereto is four. In this case, the coating mechanism  40  has a simple structure and is easy to operate. 
         [0045]    As shown in  FIG. 5 , the packaging system of this embodiment may further include: a bonding device, which includes a second bearing platform  50  and a heating unit  51 . The second bearing platform  50  is configured for bearing the OLED display motherboard which is formed by assembling the package cover plate  10  obtained after coating the hot melt adhesive thereon and the OLED substrate  20  in an aligned manner. The heating unit  51  is configured for, after the OLED display motherboard is formed by assembling the package cover plate  10  and the OLED substrate  20  in an aligned manner, heating the peripheral region of the package cover plate  10  to fully bond the package cover plate  10  and the OLED substrate  20 , so that an OLED display motherboard with good tightness is obtained. 
         [0046]    For example, the heating unit  51  of this embodiment is made of electrical resistance heating strip. Needless to say, the heating. unit  51  of this embodiment is not limited thereto, and may be other device with heating function. There are many existing devices with heating function, which are not elaborated here. 
         [0047]    In this embodiment, the bonding device further includes a pressing unit  52 , which is configured for, after the OLED display motherboard is formed by assembling the package cover plate  10  and the OLED substrate  20  in an aligned manner, pressing the peripheral region of the OLED display motherboard to fully bond the package cover plate  10  and the OLED substrate  20  and obtain the OLED display motherboard with good tightness. For example, the pressing unit  52  is made of flexible material. The flexible material has soft texture, and will not cause damage to the OLED display motherboard due to large pressure when pressing the peripheral region of the OLED display motherboard. 
         [0048]    Another embodiment of the present invention provides a packaging method for packaging an OLED display motherboard, the OLED display motherboard may be the OLED display motherboard described in the above embodiments, and the packaging method may be applied in the packaging device in the above embodiment and includes the following step S 01  to step S 03 . 
         [0049]    At step S 01 , hot melt adhesive  11  is coated in the peripheral region of the package cover plate  10 . 
         [0050]    This step specifically includes: firstly placing the package cover plate  10  on a first bearing platform  30 , determining positions of a plurality of reference points in the peripheral region of the package cover plate  10 , determining positional relationship between the plurality of reference points and areas to be coated with the hot melt adhesive  11 , and coating the hot melt adhesive  11  in the peripheral region of the package cover plate  10 ; thereafter, heating a area where the plurality of reference points are located in the package cover plate  10  with the hot melt adhesive  11  coated in the peripheral region thereof in this step, the hot melt adhesive  11  is heated with a temperature in a range of 95±5° C. (i.e., softening point of the hot melt adhesive  11 ). In this step, preheating the positions of the plurality of reference points allows the hot melt adhesive  11  and the positions of the plurality of reference points of the package cover plate  10  to be pre-bonded, so that gap between the package cover plate  10  and the hot melt adhesive  11  is avoided. For example, the number of the reference points is four. 
         [0051]    At step S 02 , the package cover plate  10  subjected to the above step and an OLED substrate  20  are assembled in an aligned manner in a vacuum environment. 
         [0052]    In this step, the OLED substrate  20  is disposed on a second bearing platform  50  first, the package cover plate  10  subjected to the coating in step S 01  is mechanically aligned with the OLED substrate  20  by a mechanical arm, and then precise alignment is performed. The alignment method is consistent with the existing method of aligning the OLED substrate  20  and the package cover plate  10 , and thus is not elaborated here. 
         [0053]    At step S 03 , peripheral region of the OLED display motherboard is heated in a vacuum environment to seal the package cover plate  10  and the OLED substrate  20 . 
         [0054]    In this step, the peripheral region of the OLED display motherboard is heated, that is, the heating is performed at one side of the OLED substrate  20  away from the package cover plate  10 , and the hot melt adhesive  11  is heated with a temperature in a range of 95±5° C. (i.e., softening point of the hot melt adhesive  11 ) to fully bond the package cover plate  10  and the OLED substrate  20 . Particularly, in order to better bond the package cover plate  10  and the OLED substrate  20 , for example, nitrogen is introduced into the environment where the OLED display motherboard is located, after the peripheral region of the OLED display motherboard is heated. In this case, the packaging method further includes: pressing the peripheral region of the OLED display motherboard by a pressing unit, that is, the pressing is performed by the pressing unit at the side of the package cover plate  10  away from the OLED substrate  20 , so that the package cover plate  10  and the OLED substrate  20  are bonded together more fully. Here, the pressing unit is made of flexible material, so as to avoid damage to the package cover plate in the pressing process. 
         [0055]    In the packaging method of this embodiment, the package cover plate  10  and the OLED substrate  20  of the OLED display motherboard are sealed with the hot melt adhesive  11 , and compared to the UV adhesive, the hot melt adhesive  11  is of low cost, has a simple coating process, and is easy to implement, and no curing process is needed for the hot melt adhesive  11  after the package cover plate  10  and the OLED substrate  20  are assembled in an aligned manner, therefore, the cost can be saved and production efficiency can be improved. 
         [0056]    It can be understood that, the above implementations are merely exemplary implementations configured for explaining the principle of the present invention, but the present invention is not limited thereto. For those skilled in the art, various modifications and improvements may be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also deemed as falling within the protection scope of the present invention.