Patent Publication Number: US-2023138125-A1

Title: Mask assembly and manufacturing method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims the priority to a Chinese patent application No. 202010006103.4, filed to the Patent Office of the People&#39;s Republic of China on Jan. 3, 2020 and entitled “Mask Assembly and Manufacturing Method Thereof”, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The present disclosure relates to the field of display device processing, in particular to a mask assembly and a manufacturing method thereof. 
     BACKGROUND 
     In the related art, as the display device screens, e.g. mobile phone screens become diversified, the display screen is not a traditional rectangle any more, but develops into many shapes, e.g. an active area (AA) with four rounded corners, and a top frame with a chamfered area, which poses a great challenge to the traditional linear support and overlay structure plus fine metal mask (FMM). The FMM openings of pixels in the AA of traditional rectangular screen are also arranged in a traditional straight line; while the FMM openings of pixels in the AA of a screen with a rounded or a chamfered area is also special-shaped, which will inevitably affect the stress distribution of FMM if an opening may not be designed on the FMM at a position where a material may not be evaporated. The traditional overlay structure and support structure are linear and may not block the evaporation of a material at a chamfer, if an opening is designed on the FMM at a position where a material may not be evaporated. 
     SUMMARY 
     An embodiment of the present disclosure provides a mask assembly, including: 
     a metal frame, wherein the metal frame is provided with a first operation window penetrating through a thickness direction of the metal frame; 
     a metal plate, wherein the metal plate and the metal frame are stacked, the metal plate includes a body and a plurality of connecting posts, the body is located in the first operation window and is provided with a plurality of second operation windows penetrating through a thickness direction of the body, the plurality of connecting posts are arranged at intervals along an outer periphery of the body, the metal frame is provided with a plurality of grooves matched with the plurality of connecting posts, the plurality of grooves correspond to the plurality of connecting posts one by one and communicate with the first operation window, and the plurality of connecting posts are located in the grooves and welded to the metal frame; and 
     at least one FMM, wherein the at least one FMM is located on one side, away from the metal frame, of the metal plate; and the at least one FMM is provided with a plurality of openings penetrating through a thickness direction of the at least one FMM, and is welded to the metal frame. 
     In a possible implementation, according to the mask assembly provided by the embodiment of the present disclosure, the at least one FMM is welded to an area, located between two adjacent connecting posts, of the metal frame. 
     In a possible implementation, according to the mask assembly provided by the embodiment of the present disclosure, the at least one FMM includes a support connecting part and an opening part, the support connecting part is at least located at two ends of the opening part and is welded to the metal frame, and the plurality of openings are arranged in the opening part. 
     In a possible implementation, according to the mask assembly provided by the embodiment of the present disclosure, an outer contour of the body is the same as that of the first operation window, and an outer peripheral wall of the body is attached to an inner peripheral wall of the first operation window. 
     In a possible implementation, according to the mask assembly provided by the embodiment of the present disclosure, the plurality of second operation windows are arranged at intervals; and 
     there are a plurality of FMMs, and each of the FMMs blocks at least one of the second operation windows. 
     In a possible implementation, according to the mask assembly provided by the embodiment of the present disclosure, the plurality of second operation windows are arranged in multiple rows and multiple columns, the plurality of FMMs correspond to multiple columns of the second operation windows one by one, each of the FMMs blocks the second operation windows in one column of the second operation windows, and two ends of the each FMM in a length direction are welded to the metal frame. 
     In a possible implementation, according to the mask assembly provided by the embodiment of the present disclosure, two connecting posts extending in a column extension direction of the second operation windows are arranged between two adjacent columns of second operation windows; and the two connecting posts are respectively located at two ends, along the column extension direction, of the second operation windows; and 
     two connecting posts extending in the column extension direction of the second operation windows are arranged at two ends, along the row extension direction, of the second operation windows; and the two connecting posts are respectively located at two ends, along the column extension direction, of the second operation windows. 
     In a possible implementation, according to the mask assembly provided by the embodiment of the present disclosure, two connecting posts extending in a row extension direction of the second operation windows are arranged between two adjacent rows of the second operation windows; and the two connecting posts are respectively located at two ends, along the row extension direction, of the second operation windows; and 
     two connecting posts extending in the row extension direction of the second operation windows are arranged at two ends, along the column extension direction, of the second operation windows; and the two connecting posts are respectively located at two ends, along the row extension direction, of the second operation windows. 
     In a possible implementation, according to the mask assembly provided by the embodiment of the present disclosure, a depth of each of the grooves is H, and a thickness of each of the connecting posts is h, and H and h satisfy the condition of H≥h. 
     In a possible implementation, according to the mask assembly provided by the embodiment of the present disclosure, H and h satisfy the condition of H−h≥10 μm. 
     In a possible implementation, according to the mask assembly provided by the embodiment of the present disclosure, a shape of the second operation window is a rectangle with a rounded or chamfered area. 
     In another aspect, an embodiment of the present disclosure also provides a manufacturing method of the mask assembly, wherein the method includes: 
     manufacturing the metal frame provided with the first operation window and the plurality of grooves; 
     manufacturing the metal plate including the body and the plurality of connecting posts; 
     where the body is provided with the plurality of second operation windows; 
     manufacturing the at least one FMM provided with the plurality of openings; 
     stacking the at least one FMM and the metal plate on the metal frame, where the at least one FMM is located on one side, away from the metal frame, of the metal plate; and 
     welding the plurality of connecting posts of the metal plate in the grooves, and welding the at least one FMM to the metal frame. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a front view of a metal frame of a mask assembly provided by the embodiment of the present disclosure. 
         FIG.  2    is a front view of a metal plate of a mask assembly provided by the embodiment of the present disclosure. 
         FIG.  3    is an assembly front view of a metal frame and a metal plate of a mask assembly provided by the embodiment of the present disclosure. 
         FIG.  4    is a front view of a FMM of a mask assembly provided by the embodiment of the present disclosure. 
         FIG.  5    is a front view of a mask assembly provided by the embodiment of the present disclosure. 
         FIGS.  6 A to  6 E  are respective front views of a second operation window after assembling a metal plate of a mask assembly and a FMM provided by the embodiment of the present disclosure. 
         FIG.  7    is a schematic flow chart of a manufacturing method of a mask assembly provided by the embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Embodiments of the present disclosure are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar designations from beginning to end indicate the same or similar elements or elements having the same or similar functions. The embodiments described below by reference to the accompanying drawings are exemplary, which are intended only to explain the present disclosure and are not to be construed as limiting the present disclosure. 
     In the description of the present disclosure, it should be understood that the orientation or positional relationship indicated by the terms “length”, “width”, “thickness”, “upper”, “lower”, “inner”, “outer”, “circumferential” and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present disclosure and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation or are structured and operated in the specific orientation. In the description of the present disclosure, “a plurality of” means two or more, unless otherwise specified. 
     In the description of the present disclosure, it should be noted, unless otherwise explicitly specified and defined, the terms “installation” and “connection” are to be understood in a broad sense, for example, a fixed connection, a removable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection, or a connection through an intermediate medium, and a communication within two elements. For a person of ordinary skill in the art, the specific meaning of the above terms in the context of the present disclosure may be understood in specific cases. 
     Below is the description of the mask assembly  100  according to an embodiment of the present disclosure and with reference to  FIGS.  1 - 5   . 
     As shown in  FIGS.  1 - 5   , a mask assembly  100  according to embodiments of the present disclosure includes a metal frame  1 , a metal plate  2  and at least one FMM  3 . 
     Specifically, as shown in  FIGS.  1 - 3   , the metal frame  1  is provided with a first operation window  11  penetrating through a thickness direction of the metal frame  1 , and may allow a material to be evaporated to pass through. 
     The metal plate  2  is laminated with the metal frame  1 , and the metal plate  2  includes a body  21  that is arranged opposite to the first operation window  11  and located in the first operation window  11 . Thus, an overlapping area between the body  21  and the metal frame  1  may be avoided, and the situation of a residue of chemical between the metal frame  1  and the body  21  may be improved. 
     The body  21  is provided with a plurality of second operation windows  211  penetrating through a thickness direction of the body, and the plurality of second operation windows  211  are located in the first operation window  11 . The plurality of second operation windows  211  may allow a material to be evaporated to pass through, and match the shapes and sizes of display areas of display panels to be evaporated. The plurality of second operation windows  211  of the metal plate  2  allow evaporating a material to be evaporated in a display area of each display panel, and the body  21  covers the areas outside the display areas to avoid evaporating a material at a position where the material should not be evaporated. 
     As shown in  FIG.  1    and  FIG.  2   , the plurality of connecting posts  22  are arranged at intervals on the outer periphery of the body  21  and along the circumferential direction of the body  21 . The metal frame  1  may be provided with a plurality of grooves  12  matched with the connecting post  22 , and the grooves  12  are communicated with the first operation window  11 , do not penetrate through a thickness direction of the metal frame  1 , and correspond to the plurality of connecting posts  22  one by one. The connecting posts  22  are located in the grooves  12  and welded to the metal frame  1 , so that at least part of the connecting posts  22  may sink into the grooves  12 . 
     As shown in  FIG.  4    and  FIG.  5   , the FMM  3  is laminated with the metal plate  2  and located on one side, away from the metal frame  1 , of the metal plate  2 ; the FMM  3  is provided with a plurality of openings  321  penetrating through a thickness direction of the FMM, the openings  321  may allow a material to be evaporated to pass through, and at least part of the openings  321  may match the shapes and sizes of light emitting areas in display areas of the evaporated display panels. The opening  321  of the FMM  3  allows evaporating a material to be evaporated in the light emitting area in the display area of each display panel, and other parts of the FMM  3  cover the areas outside the light emitting areas to avoid evaporating a material at a position where the material should not be evaporated. 
     The FMM  3  may be directly welded to the metal frame  1  to enhance the fixing reliability of the FMM  3  and improve the problem of wrinkling of the FMM  3 . 
     Specifically, according to the mask assembly  100  provided by the embodiment of the present disclosure, a plurality of connecting posts  11  are arranged at intervals on the outer periphery of the body  21  of the metal plate  2 , and a plurality of grooves  12  matched with the connecting posts  22  are arranged on the metal frame  1 . By this way, the connecting posts  22  may sink into the grooves  12  to reduce the distance between the FMM  3  and the metal frame  1 , facilitate the welding of the FMM  3  to the metal frame  1 , enhance the fixing reliability of the FMM  3  and improve the problem of wrinkling of the FMM  3 . In addition, the FMM  3  is welded to the metal frame  1 , so as to avoid an overlapping area between the FMM  3  and the metal plate  2  in the area where the metal frame  1  is located, and improve the situation of a residue of chemical between the metal plate  2  and the FMM  3 . 
     In addition, during the evaporation process of the mask assembly  100 , the metal plate  2  may fluctuate up and down. The FMM  3  is welded to the metal frame  1  rather than the metal plate  2 , so as to improve the problem of wrinkling of the FMM  3  caused by the fluctuation of the metal plate  2 , and enhance the working reliability of the mask assembly  100 . 
     Optionally, according to the mask assembly  100  provided by the embodiment of the present disclosure, the FMM  3  may be welded to an area, located between two adjacent connecting posts  22 , of the metal frame  1 . 
     Specifically, during the evaporation process of the mask assembly  100 , the metal plate  2  may fluctuate up and down. The FMM  3  is welded to an area, located between two adjacent connecting posts  22 , of the metal frame  1  rather than welded to the metal plate  2 , so as to improve the problem of wrinkling of the FMM  3  caused by the fluctuation of the metal plate  2 , enhance the working reliability of the mask assembly  100 , and avoid the problem that a residue of chemical in a welding area between the FMM  3  and the metal plate  2  cannot be removed. 
     Optionally, according to the mask assembly  100  provided by the embodiment of the present disclosure, as shown in  FIG.  4   , the FMM  3  may specifically include a support connecting part  31  and an opening part  32 , the opening part  32  is internally provided with a plurality of openings  321  and used for blocking the second operation windows  211 , the support connecting part  31  is used for supporting the opening part  32  to improve the strength of the FMM  3 , and the support connecting part  31  may be connected to the metal frame  1 . Specifically, the support connecting part  31  may be arranged at two ends of the opening part  32  along the length direction, and may also be arranged around the opening part  32 . A size of each opening  321  is smaller than that of a second operation window  211 , and the opening  321  allows a material to be evaporated to pass through. The evaporated material may be evaporated to a corresponding position of each display panel through the opening  321  on the FMM  3 . 
     For example, in the mobile phone and flat panel display technologies, active matrix organic light emitting diode (AMOLED) will gradually become the mainstream of the next generation display due to the advantages of self-illumination, bright colors, low power consumption and wide viewing angle. The self-illumination principle of AMOLED is as follows: taking an indium tin oxide (ITO) electrode and a metal electrode made on the back plate as an anode and a cathode of a device, organic semiconductor materials and luminescent materials are evaporated on a substrate. Driven by a certain voltage, electrons and holes are injected into electron and hole transport layers from the cathode and the anode respectively, and then migrate to a luminescent layer through the electron and hole transport layers respectively and meet in the luminescent layer, forming excitons and exciting luminescent molecules that emit visible light after radiation relaxation. 
     AMOLED may be evaporated by the above mask assembly  100 ; that is, an organic semiconductor material and a luminescent material are evaporated to a substrate. In the evaporation process, the organic semiconductor material and the luminescent material are located on one side, facing away from the FMM  3 , of the metal frame  1 ; the substrate is located on one side, facing away from the metal frame  1 , of the FMM  3 ; and the luminescent material and the organic semiconductor material may be evaporated to the substrate by sequentially passing through the first operation window  11 , the second operation windows  211  and the openings  321  of the FMM  3 . 
     Optionally, according to the mask assembly  100  provided by the embodiment of the present disclosure, in order to meet the requirements for manufacturing display areas with different shapes, the second operation windows  211  may be set into different shapes according to actual needs, which may be specifically a regular shape, as shown in  FIGS.  6 A to  6 E , or an irregular shape, e.g. a rectangle, a circle, an oval, a triangle or a rectangle with a rounded or chamfered area. Based on the requirements for display areas of different shapes, the shapes of the second operation windows  211  in the metal plate  2  need to be changed only for evaporation and blocking, and the FMM  3  may be designed into a universal type to extend the application range of the mask assembly  100  in a display device, which may not only meet the requirements for car rearview mirrors, watches and audio products, but also be combined with virtual reality (VR) and artificial intelligence (AI) technologies to produce more products shown in trapezoid, half circle, concave and other special shapes. Such settings greatly improve the color mixing, and provide stable yield. 
     Optionally, according to the mask assembly provided by the embodiment of present disclosure, the surface, away from the metal frame  1 , of the metal plate  2  may be flush with the area of the surface of the metal frame  1  that faces toward the metal plate  2  and is not provided with the groove  12 ; alternatively, the surface, away from metal frame  1 , of the metal plate  2  may be lower than the area of the surface of the metal frame  1  that faces toward the metal plate  2  and is not provided with the groove  12 , so as to facilitate welding connection between the FMM  3  and the metal frame  1 . 
     Specifically, a depth of the groove  12  is set as H and a thickness of the connecting post  22  as h, where H and h satisfy the condition of H≥h. By this way, the connecting posts  22  may all sink into the grooves  12 , thus avoiding the problem that the FMM  3  cannot be welded to the metal frame  1  caused by the connecting posts  22  supporting the FMM  3 . As a result, the fixing reliability of the FMM  3  is enhanced, and the problem of wrinkling of the FMM  3  is improved. 
     Further, H and h may satisfy the condition of H−h≥10 h wrinkle, to ensure that the connecting posts  22  may all sink into the grooves  12 , thus, avoiding the problem that the FMM  3  cannot be welded to the metal frame  1  caused by the connecting posts  22  supporting the FMM  3 . As a result, the fixing reliability of the FMM  3  is enhanced, and the problem of wrinkling of the FMM  3  is improved. 
     Optionally, according to the mask assembly provided by the embodiment of the present disclosure, as shown in  FIG.  3   , the outer contour of the body  21  may be the same as that of the first operation window  11 , and the outer peripheral wall of the body  21  is attached to the inner peripheral wall of the first operation window  11 . Therefore, a gap between the outer peripheral wall of the body  21  and the inner peripheral wall of the first operation window  11  may be avoided, the possibility of an evaporated material passing through the gap between the inner peripheral wall of the first operation window  11  and the outer peripheral wall of the body  21  is improved, and the material may not be evaporated at a position where the evaporation is unnecessary. 
     Optionally, according to some embodiments of the present disclosure, as shown in  FIG.  2   , the plurality of second operation windows  211  arranged at intervals, and one of the second operation windows  211  corresponds to a display area of one display panel. Therefore, the mask assembly  100  may evaporate a plurality of display panels at the same time, and the working efficiency of the mask assembly  100  is improved. Further, as shown in  FIG.  5   , there are a plurality of fine metal mask (FMMs)  3 , and each of the FMMs  3  blocks at least one of the second operation windows  211 . In case a problem occurs in the evaporation process of one or more display panels, only the FMM  3  corresponding to the display panel having an evaporation problem may be disassembled, and not all of the display panels shall be disassembled, thereby simplifying the maintenance process and reducing the cost. 
     Optionally, as shown in  FIG.  2    and  FIG.  5   , the plurality of second operation windows  211  may be arranged in multiple rows and columns, and the number of second operation windows  211  in one column is smaller than that in one row. The plurality of FMMs  3  may correspond to the plurality of columns of second operation windows  211  one by one, and each of the FMMs  3  blocks the second operation windows  211  in one or more columns of second operation windows  211 , so that two ends of the FMMs  3  in the length direction may be welded to the areas, located between two adjacent connecting posts  22 , of the metal frame  1 . Alternatively, the plurality of FMMs  3  may correspond to the plurality of rows of second operation windows  211  one by one, and each of the FMMs  3  blocks the second operation windows  211  in one or more rows of second operation windows  211 . Therefore, in case a problem occurs in the evaporation process of some display panels, only the FMMs  3  corresponding to the display panels having an evaporation problem may be disassembled, and not all of the display panels shall be disassembled, thereby simplifying the maintenance process and reducing the cost at the same time. 
     Optionally, as shown in  FIG.  2   , two connecting posts  22  extending in a column extension direction of the second operation windows  211  are arranged between two adjacent columns of second operation windows  211 ; and the two connecting posts  22  are respectively located at two ends, along the column extension direction, of the second operation windows  211 . Two connecting posts  22  extending in a column extension direction of the second operation windows  211  are arranged at two ends, along the row extension direction, of the second operation windows  211 ; and the two connecting posts  22  are respectively located at two ends, along the column extension direction, of the second operation windows  211 . That is, it may be considered that the body  21  of the metal plate  2  includes a first strip-shaped body part extending along the column direction of the second operation windows  211 , and the connecting posts  22  may be a part where the first strip-shaped body part extends out of the body at two ends. Therefore, the fixing reliability of the metal plate  2  may be improved, and the phenomenon of distortion of the metal plate  2  may be improved. 
     Optionally, as shown in  FIG.  2   , two connecting posts  22  extending along the row extension direction of the second operation windows  211  are arranged between two adjacent rows of the second operation windows  211 ; and the two connecting posts  22  are respectively located at two ends, along the row extension direction, of the second operation windows  211 . Two connecting posts  22  extending along the row extension direction of the second operation windows  211  are arranged at two ends, along the column extension direction, of the second operation windows  211 ; and the two connecting posts  22  are respectively located at two ends, along the row extension direction, of the second operation windows  211 . That is, it may be considered that the body  21  of the metal plate  2  includes a second strip-shaped body part extending along the row direction of the second operation windows  211 , and the connecting posts  22  may be a part where the second strip-shaped body part extends out of the body at two ends. Therefore, the fixing reliability of the metal plate  2  may be improved, and the phenomenon of distortion of the metal plate  2  may be improved. 
     Based on the same inventive concept, embodiments of the present disclosure also provide a manufacturing method of the above mask assembly, and as shown in  FIG.  7   , the manufacturing method specifically includes the following steps. 
     S1. A metal frame provided with a first operation window is manufactured. 
     S2. A metal plate including a body provided with a plurality of second operation windows and a plurality of connecting posts is manufactured. 
     S3. At least one FMM provided with a plurality of openings is manufactured. 
     S4. The at least one FMM and the metal plate are stacked on the metal frame; where the at least one FMM is located on one side, away from the metal frame, of the metal plate. 
     S5. The plurality of connecting posts of the metal plate are welded in the grooves, and the at least one FMM is welded to the metal frame. 
     Specifically, according to the manufacturing method of the mask assembly provided by the embodiment of the present disclosure, a plurality of connecting posts are arranged at intervals on the outer periphery of the body of the metal plate, and a plurality of grooves matched with the connecting posts are arranged on the metal frame. By this way, the connecting posts may sink into the grooves to reduce the distance between the FMM and the metal frame, facilitate the welding of the FMM to the metal frame, enhance the fixing reliability of the FMM  3  and improve the problem of wrinkling of the FMM  3 . In addition, the manufacturing method may avoid the situation that there is a residue of chemical between the FMM and the metal plate when the FMM is welded to the metal plate. 
     In addition, during the evaporation process of the mask assembly, the metal plate may fluctuate up and down. The FMM is welded to the metal frame rather than the metal plate, so as to improve the problem of wrinkling of the FMM caused by the fluctuation of the metal plate, and enhance the working reliability of the mask assembly. 
     In the description of the specification, descriptions referring to the terms “one embodiment”, “some embodiments”, “schematic embodiments”, “examples”, “specific examples”, or “some examples” mean that specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In the specification, the schematic expressions of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. 
     The embodiments of the present disclosure are shown and described above. For a person of ordinary skill in the art, it should be understood that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present disclosure; and the scope of the present invention is defined by the claims appended thereto and the equivalents thereof.