Patent Publication Number: US-11048460-B2

Title: Display module including a light diffusion agent and display apparatus having the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 15/166,940, filed on May 27, 2016 in the U.S. Patent and Trademark Office, which claims priority from Korean Patent Application No. 10-2015-0074954, filed on May 28, 2015 in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND 
     Field 
     Apparatuses and methods consistent with exemplary embodiments relate to a display module and a display apparatus having the same, and more particularly, to a display module with reduced moire and a display apparatus having the same. 
     Description of the Related Art 
     In display apparatuses having display modules being used as imaging apparatuses like cameras, it may be difficult for the user to identify a screen due to moire caused in screens of the display apparatuses. As light emitting device packages are arranged in a grid form in the display module, specific spaces may be formed between the light emitting device packages. The moire may be caused by a sharp pattern such as a checkerboard formed by the specific spaces. 
     In recent years, a method of attaching a diffuser film to the display module has been proposed to overcome the moire. When the diffuser film is used, light emitted from the light emitting device may be diffused through the diffuser film, the specific spaces formed between the light emitting device packages may be filled with the light diffused through the diffuser film, and thus the moire may be reduced. 
     However, since the diffuser film has to be attached to the display module after the entire surface of the display module is smoothed by coating an adhesive in a space between optical devices, the diffuser film attaching method may be cumbersome. Due to the cumbersome process, the material cost may be increased and the unit cost of the product may be increased. 
     In response to the diffuser film being attached to the display module, the screen displayed in the display module may be blurred, and a viewing angle may be reduced due to full reflection of the light in a side of the screen. The contrast ratio may be degraded due to the diffuser film. 
     SUMMARY 
     Exemplary embodiments may overcome the above disadvantages and other disadvantages not described above. Also, an exemplary embodiment is not required to overcome the disadvantages described above, and an exemplary embodiment may not overcome any of the problems described above. 
     One or more exemplary embodiments provide a display module with a simplified fabrication process and improved moire, visibility and viewing angle, and a display apparatus having the same. 
     According to an aspect of an exemplary embodiment, there is provided a display module including a circuit board; a plurality of light emitting device packages disposed on the circuit board and electrically coupled to the circuit board; and a coating unit coated with coating solution containing a light diffusion agent covers the plurality of light emitting device packages and fills in a gap between the plurality of light emitting device packages, wherein the coating unit further includes at least one first light diffusion part that is curvedly formed on a surface of the coating unit onto which light emitted from the light emitting device packages is incident. 
     According to an aspect of another exemplary embodiment, there is provided a display apparatus including a plurality of display modules, each of the plurality of display modules including a plurality of light emitting device packages and a coating unit, the plurality of light emitting device packages being disposed on a circuit board and electrically coupled to the circuit board, and the coating unit coated with coating solution containing a light diffusion agent covers the plurality of light emitting device packages and fills in a gap between the plurality of light emitting device packages; and a controller configured to electrically couple the plurality of display modules and control the plurality of display modules, wherein the coating unit further includes at least one first light diffusion part that is curvedly formed on a surface of the coating unit onto which light emitted from the plurality of light emitting device packages is incident. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       The above and/or other aspects will be more apparent by describing certain exemplary embodiments with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective view illustrating a display apparatus according to an exemplary embodiment; 
         FIG. 2  is a schematic block diagram illustrating a configuration of a display apparatus according to an exemplary embodiment; 
         FIG. 3  is a partial cross-sectional diagram illustrating a display module taken along line III-III of  FIG. 1 ; 
         FIG. 4  is a flowchart sequentially illustrating a process of coating-treating a display module illustrated in  FIG. 1 ; 
         FIG. 5  is a partial cross-sectional diagram illustrating a display module according to another exemplary embodiment; 
         FIG. 6  is a partial cross-sectional diagram illustrating a display module according to another exemplary embodiment; 
         FIG. 7  is a partial cross-sectional diagram illustrating a display module according to another exemplary embodiment; 
         FIG. 8  is a partial cross-sectional diagram illustrating a display module according to another exemplary embodiment; and 
         FIGS. 9 and 10  are partial cross-sectional diagrams illustrating modified examples of a fourth light diffusion part illustrated in  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments are described in greater detail below with reference to the accompanying drawings. 
     In the following description, like drawing reference numerals are used for like elements, even in different drawings. The matters defined in the description, such as detailed construction and elements, are provided to assist in a comprehensive understanding of the exemplary embodiments. However, it is apparent that the exemplary embodiments can be practiced without those specifically defined matters. Also, well-known functions or constructions are not described in detail since they would obscure the description with unnecessary detail. 
     Referring to  FIG. 1 , the display apparatus  1  according to an exemplary embodiment may include a main body  2  and a plurality of display modules  10 . 
     The display modules  10  may be disposed on a front surface of the main body  2  and a controller  3  may be included inside the main body  2 . Referring to  FIG. 2 , the controller  3  may be electrically coupled to the plurality of display modules  10 , and control an image to be displayed in the plurality of display modules  10 . That is, the user may input information for the image to be displayed through an input unit  4 , and the controller  3  may receive the information and control the plurality of display modules  10  to display one image in the display apparatus  1 . 
     The main body  2  may include coupling units  5   a  and  5   b  in sides thereof to couple and use a plurality of display apparatuses  1 . For example, the coupling units  5   a  and  5   b  may include a protrusion  5   a  formed in one side of the main body  2  and a hole  5   b  formed in the other side of the main body  2 . The user may use the plurality of display apparatuses  1  to display a huge image by coupling the plurality of display apparatuses  1  through mutual coupling of the protrusion  5   a  and the hole  5   b.    FIG. 1  illustrates that the protrusion  5   a  is formed in a right side and a lower side of the main body  2  and the hole  5   b  is formed in a left side and an upper side of the main body  2 , but this is not limited thereto, and the positions of the protrusion  5   a  and the hole  5   b  may be mutually changed. The protrusion  5   a  and the hole  5   b  may be formed in opposite sides of the main body  2  to mutually couple the display apparatuses  1 . 
     Referring to  FIG. 3 , a plurality of display modules  10  according to an exemplary embodiment may be disposed in a front of the main body  2 , and the display module  10  may include a circuit board  11 , a light emitting device package  12 , and a coating unit  13 . 
     The circuit board  11  may be formed of an insulating material such as an epoxy resin or a phenol resin, and may be electrically coupled to a light emitting device  14 . The circuit board  11  may be electrically coupled to the controller  3  and the light emitting device  14  may emit specific light according to control of the controller  3 . 
     A plurality of light emitting device packages  12  may be disposed on the circuit board  11 , and the light emitting device  14  may be included in each light emitting device package  12 . 
     The plurality of light emitting device packages  12  may be disposed at preset intervals on the circuit board  11  in a grid form, and a gap  16  may be formed between the plurality of light emitting device packages  12 . The gap  16  may be the main cause of the moire. 
     For example, the light emitting device  14  may include a red (R) device  14   a,  a green (G) device  14   b,  and a blue (B) device  14   c  and one R device  14   a,  one G device  14   b,  and one B device  14   c  may be disposed in the light emitting device package  12 , but this is not limited thereto. In another example, the light emitting device  14  may include only one among the R device  14   a,  the G device  14   b,  and the B device  14   c.  The light emitting device packages  12  including only corresponding one among the R device  14   a,  the G device  14   b,  and the B device  14   c  may be disposed in order. However, an example that all the R device  14   a,  the G device  14   b,  and the B device  14   c  are included in one light emitting device package  12  will be described in the exemplary embodiment. The arrangement order of the R device  14   a,  the G device  14   b,  and the B device  14   c  may also be changed. 
     The coating unit  13  may be coating-treated on the circuit board  11  to include the light emitting device packages  12 , and may contain at least one among a waterproof agent, silicon, and an antistatic agent. The display module according to an exemplary embodiment may accomplish the waterproof function and the antistatic prevention function and improve a viewing angle. The coating unit  13  may include a first light diffusion part  15  curvedly formed in a portion thereof corresponding to a portion of the circuit board  11  in which the light emitting device package  12  is disposed. For example, the first light diffusion part  15  may be concavely or convexly formed in a gently curved form. 
     Referring to  FIG. 4 , a liquid coating solution may be coated higher than a height of the light emitting device package  12  by a preset height (S 10 ), and the coated coating-solution may be leveled out through a roller (S 20 ). Subsequently, the first light diffusion part  15  having a concave form may be formed when the coating solution is pressed using a mold so that the first light diffusion part  15  may face the light emitting device package  12  (S 30 ). The coating solution may be cured (S 40 ). 
     Since the coating unit  13  contains a light diffusion agent, the light emitted from the light emitting device  14  may pass through the coating unit  13  and may be diffused by scattered reflection. Since the light may also be provided to a portion of the circuit board  11  in which the light is not provided by the gap  16  as a cause of the moire and the grid pattern is formed, the moire may be minimized. Also, it may be unnecessary to coat the adhesive and to attach the separate diffuser film, and thus the fabricating process of the display module  10  may be simplified. 
     The first light diffusion part  15  may be convexly formed to be away from the light emitting device package  12 . Since the light is inverted after a focal length and diffused even in the first light diffusion part  15  having the convex form, the first light diffusion part having the convex form may have the effect similar to the first light diffusion part having the concave form. Even in response to the light being inverted, the entire image is not reversed but an image for an individual pixel is reversed. Accordingly, since the user recognizes the light emitted from the light emitting device  14  as one integrated color, the arrangement order of the pixels may not affect the entire image regardless of the arrangement order of RGB or BGR. 
     For example, the first light diffusion part  15  may be formed in all portions of the coating unit  13  corresponding to the portions of the circuit board  11  in which the light emitting device packages  12  are formed. In another example, the first light diffusion part  15  may be formed in partial portions of the coating unit  13  corresponding to the portions of the circuit board  11  in which the light emitting device packages  12  are formed. 
     The light emitted from the light emitting device  14  may be further diffused by the first light diffusion part  15  curvedly formed while passing through the coating unit  13 , and an amount of the light provided to the portion of the circuit board  11  in which the light is not provided by the gap  16  and the grid pattern is formed may be increased. Accordingly, the moire and the viewing angle may be improved. 
     A display apparatus  1  according to another exemplary embodiment will be described with reference to  FIG. 5 . The same reference numeral is used for the main body  2  as the same element in another exemplary embodiment, and thus detailed description thereof will be omitted and only a display module  20  having a different configuration from the display module  10  will be described. 
     A plurality of display modules  20  according to another exemplary embodiment may be disposed in a front of the main body  2  and the display module  20  may include a circuit board  21 , a light emitting device package  22 , and a coating unit  23 . However, the circuit board  21  and the light emitting device package  22  are the same as the circuit board  11  and the light emitting device package  12  in an exemplary embodiment, and thus detailed description thereof will be omitted, and only the coating unit  23  having a different configuration from the coating unit  13  will be described. 
     In an exemplary embodiment, the coating unit  23  may be formed higher than a height of the light emitting device package  22  by a preset height by coating a coating solution containing a light diffusion agent, leveling the coated coating solution through a roller, and curing the leveled coating solution. The coating unit  23  of the display module  20  form a light diffusion part  25  and the first light diffusion part  25  having a curved form may be formed to face the light emitting device package  22  by pressing the coating solution using a mold before the coating solution is cured. For example, the first light diffusion part  25  may be concavely formed as illustrated in  FIG. 5 . In another example, the first light diffusion part  25  may be convexly formed. 
     The display module  20  according to another exemplary embodiment may include a second light diffusion part  27  disposed on the coating unit  23  in which the first light diffusion part  25  is formed. The second light diffusion part  27  may include a microlens convexly formed from the first light diffusion part  25 . The microlens may be formed through a dropping process of an inkjet coating ink or a nano imprinting process using a mold. However, the method of forming the microlens is not limited thereto, and the microlens may be formed through various methods. 
       FIG. 5  illustrates that one second light diffusion part  27  is formed on a central portion of the first light diffusion part  25  and two second light diffusion parts  27  are formed on an edge of the first light diffusion part  25 , but this is not limited thereto. Two or more second light diffusion parts  27  may be formed along the edge of the first light diffusion part  25 . For example, one second light diffusion part  27  may be disposed on the central portion of the first light diffusion part  25  and four second light diffusion parts  27  may be disposed on the edge of the first light diffusion part  25  to form a mutual right angle in consideration of the unit cost of the product according to a fabrication process of the second light diffusion part  27 . 
     Since the second light diffusion part  27  is formed in the display module  20  according to another exemplary embodiment, the light emitted from the light emitting device  24  may be primarily diffused in the first light diffusion part  25  and secondarily diffused in the second light diffusion part  27 . Accordingly, an amount of the light diffused to the portion in which the light is not provided by a gap  26  and thus the grid pattern is formed may be further increased. The moire and the viewing angle may be improved. 
     A display apparatus  1  according to another exemplary embodiment will be described with reference to  FIG. 6 . The same reference numeral is used for the main body  2  as the same element in another exemplary embodiment, and thus detailed description thereof will be omitted and only a display module  30  having a different configuration from the display module  10  will be described. 
     A plurality of display modules  30  according to another exemplary embodiment may be disposed in a front of a main body  2  and the display module  30  may include a circuit board  31 , a light emitting device package  32 , and a coating unit  33 . However, the circuit board  31  and the light emitting device package  32  are the same as the circuit board  11  and the light emitting device package  12  in an exemplary embodiment, and thus detailed description thereof will be omitted, and only the coating unit  33  having a different configuration from the coating unit  13  will be described. 
     The coating unit  33  may contain a light diffusion agent so that light emitted from the light emitting device  34  may be diffused and provided even to a gap  36 . 
     The coating unit  33  according to another exemplary embodiment may be formed in such a manner that an amount of the light diffusion agent contained in a portion of the coating unit  33  corresponding to a portion of the circuit board  31  in which the light emitting device package  32  is disposed may be more than an amount of the light diffusion agent contained in a portion of the coating unit  33  corresponding to a portion of the circuit board  31  in which the gap  36  is formed. 
     A method of coating the coating unit  33  according to another exemplary embodiment will be described. First, the gap  36  may be filled up with a coating solution containing a relatively small amount of the light diffusion agent up to a height of the light emitting device package  32 . Then, a coating solution containing a relatively large amount of the light diffusion agent to be coated on an upper surface of the light emitting device package  32  by a preset height. Subsequently, the coating solution containing a relatively small amount of the light diffusion agent may be coated on the gap  36  by a height of the coating solution coated on the upper surface of the light emitting device package  32 . The first light diffusion part  35  may be concavely formed in the coating unit  33  coated on the upper surface of the light emitting device package  32  by pressing the coating solution through a mold so that the first light diffusion part  35  may face the light emitting device package  32 . However, the method of coating the coating unit  33  is not limited thereto, and any method of forming the coating unit  33  in such a manner that the portions of the coating unit  33  corresponding to the upper surface of the light emitting device package  32  and the gap  36  contain different amounts of the light diffusion agent from each other may be used. 
     In the display module  30  according to another exemplary embodiment, the light emitted from the light emitting device  34  may be further diffused in the first light diffusion part  35  and thus the amount of the light provided to the portion in which the light is not be provided by the gap  36  and the grid pattern is formed may be increased. The moire and the visibility may be improved. 
     A display apparatus  1  according to another exemplary embodiment will be described with reference to  FIG. 7 . The same reference numeral is used for the main body  2  as the same element in another exemplary embodiment, and thus detailed description thereof will be omitted and only a display module  40  having a different configuration from the display module  10  will be described. 
     A plurality of display modules  40  according to another exemplary embodiment may be disposed in a front of the main body  2  and the display module  40  may include a circuit board  41 , a light emitting device package  42 , and a coating unit  43 . However, the circuit board  41  and the coating unit  43  are the same as the circuit board  11  and the coating unit  13  in an exemplary embodiment, and thus detailed description thereof will be omitted, and only the light emitting device package  42  having a different configuration from the light emitting device package  12  will be described. 
     As in an exemplary embodiment, the light emitting device package  42  may include an R device  44   a,  a G device  44   b,  and a B device  44   c  in the inside thereof, but this is not limited thereto. The light emitting device package  42  may include only any one among the R device  44   a,  the G device  44   b,  and the B device  44   c.  The light emitting device packages  42  may be disposed in a grid form, and thus a gap  46  may be formed between the light emitting device packages  42 . The gap  46  may be a cause of the moire as described above. 
     The light emitting device package  42  according to another exemplary embodiment may include a third light diffusion part  48  concavely formed to face the circuit board  41  in a portion thereof facing a first light diffusion part  45 . For example, in response to the light emitting device package  42  being fabricated, the user may allow an upper surface of the light emitting device package  42  in which the coating unit  43  is coated to be formed in a curved form through a mold. In this example, the third light diffusion part  48  may be concavely or convexly formed in a gently curved form. 
     In the light emitting device package  42  according to another exemplary embodiment, light emitted from the light emitting device  44  may be primarily diffused through the third light diffusion part  48  and secondarily diffused through the first light diffusion part  45  of the coating unit  43 . Accordingly, the amount of the light provided to the portion in which the light may not be provided by the gap  46  and the grid pattern is formed may be increased, and thus the moire and the visibility may be improved. 
     The third light diffusion part  48  may also have a convex form like the first light diffusion part  45 . For example, the third light diffusion part  48  may be formed on the upper surfaces of all the light emitting device packages  42 . In another example, the third light diffusion part  48  may be formed only on upper surfaces of partial light emitting device packages  42 . 
     A display apparatus  1  according to another exemplary embodiment will be described with reference to  FIG. 8 . The same reference numeral is used for the main body  2  as the same element in another exemplary embodiment, and thus detailed description thereof will be omitted and only a display module  50  having a different configuration from the display module  10  will be described. 
     A plurality of display modules  50  according to another exemplary embodiment may be disposed in a front of the main body  2  and the display module  50  may include a circuit board  51 , a light emitting device package  52 , and a coating unit  53 . However, the circuit board  51  and the coating unit  53  are the same as the circuit board  11  and the coating unit  13  in an exemplary embodiment, and thus detailed description thereof will be omitted, and only the light emitting device package  52  having a different configuration from the light emitting device package  12  will be described. 
     The light emitting device package  52  may include an R device  54   a,  a G device  54   b,  and a B device  54   c,  but this is not limited thereto. The light emitting device package  52  may include only one among the R device  54   a,  the G device  54   b,  and the B device  54   c.  The light emitting device packages  52  may be disposed in a grid form, and thus a gap  56  may be formed between the light emitting device packages  52 . A third light diffusion part  58  having a curved form may be formed on an upper surface of the light emitting device package  52  as in another exemplary embodiment as illustrated in  FIG. 7 . 
     The light emitting device package  52  according to another exemplary embodiment may further include at least one fourth light diffusion part  59   a  formed adjacent to an edge of the third light diffusion part  58 . 
     For example, the fourth light diffusion part  59   a  may be formed to be inclined downward toward the edge of the light emitting device package  52  from the edge of the third light diffusion part  58 . In this example, in response to the light emitting device package  52  being fabricated, the fourth light diffusion part  59   a  may be formed through a mold. In another example, the fourth light diffusion part  59   a  may be formed by cutting a corresponding portion of the light emitting device package  52 . 
     In this example, four fourth light diffusion parts  59   a  may be formed along four sides of an upper surface of the light emitting device package  52  through a simple cutting process. However, the fourth light diffusion part  59   a  is not limited thereto, and four light diffusion parts  59   a  or more may be formed or four light diffusion parts  59   a  or less may be formed. For example, four light diffusion parts  59   a  may be formed along the four sides of the upper surface of the light emitting device package  52  and then four fourth light diffusion parts  59   a  may be additionally formed by cutting four vertex portions of the light emitting device package  52 . 
     A boundary portion between the third light diffusion part  58  and the fourth light diffusion part  59   a  may be formed to be rounded. 
     In the light emitting device package  52  according to another exemplary embodiment, the light emitted from the light emitting device  54  may be diffused through the third light diffusion part  58  and the first light diffusion part  55  as in another exemplary embodiment illustrated in  FIG. 7 , and light emitted from an edge of the light emitting device package  52  of the light emitted from the light emitting device  54  may be additionally diffused. Accordingly, the amount of the light provided to the portion in which the light may not be provided by the gap  56  and the grid pattern is formed may be increased, and thus the moire and the visibility may be improved. 
     The fourth light diffusion part  59   a  may be formed in a plane form illustrated in  FIG. 8 , but this is not limited thereto and the fourth light diffusion part may be in a curved form. For example, a fourth light diffusion part  59   b  may be formed in a concave form as illustrated in  FIG. 9 . In another example, a fourth light diffusion part  59   c  may be formed in a convex form as illustrated in  FIG. 10 . The user may allow the fourth light diffusion parts  59   b  and  59   c  to be formed through a mold in the concave form as illustrated in  FIG. 9  or in the convex form as illustrated in  FIG. 10 . Accordingly, the light emitted from the light emitting device  54  may be largely irregularly reflected and largely diffused in the fourth light diffusion parts  59   b  and  59   c,  and thus the moire and the visibility may be further improved. 
     Since the display module according to the exemplary embodiment is coating-treated using a coating solution containing a light diffusion agent, the fabrication process of the display module may be simplified. The moire and the viewing angle may be improved according to additional formation of various light diffusion parts. 
     The display apparatus according to the exemplary embodiment may be used as a huge display installed in a stage of a venue by coupling a plurality of display apparatuses. Since the moire and the viewing angle are improved in the display apparatus according to the exemplary embodiment, a sharper image may be obtained even in response to the stage may be imaged through an imaging apparatus such as a camera, and audiences in a side of the stage may also view the image displayed through the huge display. Since the display apparatus according to the exemplary embodiment has a waterproof function, the display apparatus may be installed and used in an outdoor stage even on a rainy day. The display apparatus may be used as an outdoor billboard by coupling the plurality of display apparatuses. 
     The foregoing exemplary embodiments and advantages are merely exemplary and are not to be construed as limiting the inventive concept. The present teaching can be readily applied to other types of apparatuses. Also, the description of the exemplary embodiments is intended to be illustrative, and not to limit the scope of the claims, and many alternatives, modifications, and variations will be apparent to those skilled in the art.