Patent Publication Number: US-2011070406-A1

Title: Adhesive bonding assembly for liquid crystal display

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure generally relates to liquid crystal displays, and particularly, to an adhesive bonding assembly used in a liquid crystal display. 
     2. Description of Related Art 
     Referring to  FIGS. 5 and 6 , a liquid crystal display  10  includes a liquid crystal module  11 , a backlight module  12 , and a carrier  13 . The liquid crystal module  11  includes an upper substrate  111 , a lower substrate  112 , a plurality of driver chips  113  arranged on one side of the lower substrate  112 , and a flexible printed circuit board  114 . The carrier  13  includes a frame  131  encircling around and accommodating the liquid crystal module  11  and the backlight module  12 , an outer frame  132  enclosing the liquid crystal module  11  and the backlight module  12 , and a reflecting sheet  133  connected to the frame  131  and arranged under the backlight module  12 . The flexible printed circuit board  114  can be bent to adhere to the bottom of the frame  131 . Any two of the flexible printed circuit board  114 , the lower substrate  112 , and the frame  131 , or any other members, are connected together by an adhesive tape  20 . 
     However, as liquid crystal displays are designed with increasing reduction in thickness, the contact area of the elements described above becomes smaller correspondingly, thus a thinner adhesive tape must be chosen for usage. As a result, the bonding strength reduces accordingly, and the adhesive tape may be dislodged by the restoring elastic force of the bent flexible printed circuit board  114 , resulting in detachment of the elements from each other. 
     Therefore, there is room for improvement within the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout several views, and all the views are schematic. 
         FIG. 1  is a cross-section of a first embodiment of an adhesive bonding assembly of a liquid crystal display. 
         FIG. 2  is a plan view of a second embodiment of an adhesive bonding assembly of a liquid crystal display. 
         FIG. 3  is a plan view of a plurality of micro-structures of the adhesive bonding assembly of  FIG. 2 . 
         FIG. 4  is a partial cross-section of the adhesive bonding assembly of  FIG. 2 . 
         FIG. 5  is a partially exploded, isometric view of a commonly used liquid crystal display. 
         FIG. 6  is a cross-section of the liquid crystal display of  FIG. 5   
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a first embodiment of an adhesive bonding assembly  100  used for a liquid crystal display (not shown) includes a first member  30  having a first surface  31 , and a second member  40  having a second surface  41  facing the first surface  31 , a first bonding layer  50  formed on the first surface  31 , a second bonding layer  60  formed on the second surface  41 , and an adhesive tape  70  arranged between the first bonding layer  50  and the second bonding layer  60 . The first member  30  and the second member  40  may be two components used in a backlight module or a liquid crystal module, such as a flexible circuit board and a lower substrate, a frame and a flexible circuit board, or a lower substrate and a frame. 
     In the illustrated embodiment, the first bonding layer  50  and the second bonding layer  60  are stainless steel metal layers coated on the first surface  31  of the first member  30  and the second surface  41  of the second member  40  by electroplating. The adhesive tape  70  is an acrylic glue. 
     Alternatively, the bonding layer may be defined only on the first surface  31  of the first member  30  or the second surface  41  of the second member  40 , which can also enhance the adhesion force between the first member  30  and the second member  40 . 
     Adhesive forces between the adhesive tape  70  of 20 mm in length and other member layers are tested under a peel test by using a testing device. The adhesive force between the adhesive tape  70  and an electroplated stainless steel metal layer, such as, the first bonding layer  50  or the second bonding layer  60 , is 20 N. Furthermore, the adhesive force between the adhesive tape  70  and an acrylic acid layer is 16 N, and between the adhesive tape  70  and a polyester layer is 15N. Thus, the adhesion force of the electroplated stainless steel metal layer surpasses that of the acrylic layer and the polyester layer when bonding with the adhesive tape  70 . 
     The adhesive tape  70  may have an improved adhesion force when bonded with a different material, which enhances the bonding strength of the bonding structure between the first member  30  and the second member  40 , whereby the first member  30  and the second member  40  are prevented from detaching from each other. 
       FIGS. 2 through 4  show a second embodiment of an adhesive bonding assembly  200  bonding the first member  30  and the second member  40 , the adhesive bonding assembly  200  further including an adhesive layer  80  coated on the first surface  31  of the first member  30  and an adhesive tape  90  adhered to the adhesive layer  80 . 
     The adhesive layer  80  includes a plurality of micro-structures  81 . The micro-structures  81  may be protrusions, recesses, slots, or combinations thereof, and be V-shaped, polygonal, circular, semicircular, mesh points, or any combination of at least two thereof. In the illustrated embodiment, the micro-structures  81  are pentagonal slots and formed as follows. The first member  30  includes an adhesive area (not labeled) in the first surface  31 , a plurality of printing ink points  82  is coated inside the adhesive area, and an electroplated metal layer  83  is coated on the remaining portion of the adhesive area, then the printing ink points  82  are removed to form the micro-structures  81 . 
     The micro-structures  81  can receive the adhesive material of the adhesive tape  90 , thus, the contact area between the first member  30  and the adhesive tape  90  is thereby increased. Therefore, the bonding force of the micro-structures  81  is increased, and the adhesion force between the first member  30  and the second member  40  is enhanced. 
     The adhesive tape  70  of the first embodiment is bonded with a metal layer, and the adhesive tape  90  of the second embodiment is bonded with a layer including a plurality of micro-structures  81 , which can both increase the adhesive force between the first member  30  and the second member  40 . When a liquid crystal display provides an extremely thin profile, the adhesives tapes  70 ,  90  provide sufficient adhesive forces to prevent the first member  30  and the second member  40  from detachment, thus enhancing the quality and strength of the liquid crystal display. 
     Finally, while various embodiments have been described and illustrated, the disclosure is not to be construed as being limited thereto. Various modifications can be made to the embodiments by those skilled in the art without departing from the true spirit and scope of the disclosure as defined by the appended claims.