Abstract:
A permanently-effective element for discharging any accumulation of static electrical charges from the housing of an electronic device includes a main body with an anodized layer formed on the main body. The main body defines a plurality of blind holes of varying shapes and sizes, topped with a layer of conductive paint held in place with a binding film. The incidence of oxidation of the discharging element is significantly reduced and the effectiveness of the discharging element thus improved. A method for manufacturing the housing is also provided.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to housings and method for manufacturing the housing. 
         [0003]    2. Description of Related Art 
         [0004]    A metal piece of an electronic device is typically connected to an element having a lower electric potential to allow discharge of electrostatic charges of a metallic housing of an electronic device. The element may be a cell negative pole. However, it can be difficult to securely mount the metal piece to the metallic housing. 
         [0005]    Metallic housings made of aluminum, aluminum alloy, or magnesium alloy may be directly electrically connected with the element to discharge electrostatic charges. However, the aluminum, aluminum alloy, or magnesium alloy housings are prone to oxidation, which adversely affect the discharging of electrostatic charges. 
         [0006]    Therefore, there is room for improvement within the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Many aspects of the embodiment can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the exemplary disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0008]      FIG. 1  is a cross-sectional view of an exemplary embodiment of a housing. 
           [0009]      FIG. 2  is an enlarged cross-sectional view of the area contained in the circle II of  FIG. 1 . 
           [0010]      FIG. 3  is a cross-sectional view of a main body coated with an anodized layer. 
           [0011]      FIG. 4  is a cross-sectional view of the anodized layer of  FIG. 3  with an open area. 
           [0012]      FIG. 5  is a cross-sectional view of the main body of  FIG. 4  defining a plurality of blind holes. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]      FIG. 1-2  shows a housing  100  according to an exemplary embodiment. The housing  100  includes a main body  11  having a primary surface  111 . An anodized layer  13  is formed on the primary surface  111 . The main body main body  11  defines a plurality of blind holes  15  therein. The anodized layer  13  does not completely cover the primary surface  111 , therefore defining an open area  17  which includes the areas containing the blind holes  15 . 
         [0014]    The housing  100  further includes a binding film  19  and a conductive paint layer  21 . The binding film  19  is formed/deposited on walls of the blind holes  15  and the open area  17 . The conductive paint layer  21  is formed on the binding film  19  and fills the empty areas defined by the binding films  19  in the blind holes  15 , and the open area  17 . 
         [0015]    The housing  100  may be a housing of a mobile phone, a personal digital apparatus, or a notebook computer. 
         [0016]    The main body  11  may be made of aluminum, titanium, aluminum alloy or titanium alloy. 
         [0017]    The anodized layer  13  is formed on the primary surface  111 . The anodized layer  13  has a thickness of about 10 μm to about 30 μm. 
         [0018]    The plurality of blind holes  15  are defined in the primary surface  111 . Each blind hole  15  is in the open area  17 . In the exemplary embodiment, at least one blind hole  15  differs from another blind hole  15  in size and/or shape. The longitudinal sections of the blind holes  15  may be varied. 
         [0019]    The binding film  19  mainly includes a silane coupling agent. The silane coupling agent may be 3-glycidyloxypropyltrimethoxysilane or amino silane coupling agent. 
         [0020]    The conductive paint layer  21  includes at least one kind of conductive particles selected from the group consisting of silver (Ag), cooper (Cu), carbon (C), and aurum (Au). In the exemplary embodiment, the conductive paint layer  21  includes Ag particles. In the exemplary embodiment, the anodized layer  13  fills the blind holes  15  and open area  17 . That is, the outer surface of the conductive paint layer  21  is level with the outer surface of the anodized layer  13  which is not covered with conductive paint layer  21 . 
         [0021]    When the housing  100  is used in an electronic device (not shown), the conductive paint layer  21  is electrically connected to an element (not shown) having a lower electrical potential compared to the housing  100 , by a conductor installed in the electronic device. Therefore, the electrostatic charges within the housing  100  can flow into the element to discharge electrostatic charges. The element may be connected to a cell negative pole of the electronic device. 
         [0022]    The conductive paint layer  21  and the anodized layer  13  prevent the main body  11  from oxidation, thus the ability of the housing  100  to discharge accumulated electrostatic charges will not be affected. The binding film  19  and the blind holes  15  improve the bond between the conductive paint layer  21  and the main body  11  to prevent the conductive paint layer  21  from peeling, which adversely affects the discharging of electrostatic charges. 
         [0023]    Referring to  FIG. 3 , a method for manufacturing the housing  100  is also provided. 
         [0024]    (1) The main body  11  is provided. 
         [0025]    (2) The anodized layer  13  is formed on the primary surface  111  by an anodizing process. 
         [0026]    The anodized layer  13  has a thickness of about 10 μm to about 30 μm. 
         [0027]    (3) Referring to  FIG. 4 , the anodized layer  13  is laser engraved to form an open area  17 . 
         [0028]    (4) Referring to  FIG. 5 , a laser beam passes through the open area  17  and laser engraves the main body  11  to define a plurality of blind holes  15  in the main body  11 . 
         [0029]    The blind holes  15  are defined in the primary surface  111  of the main body  11 . Each blind hole  15  is in the open area  17 . In the exemplary embodiment, a plurality of blind holes  15  with different sizes and/or shapes are defined in the main body  11  by adjusting the burning rate, burning energy, laser power density, and/or other parameters of the laser engraving process. The longitudinal sections of the blind holes  15  may be ladder-shaped, or rectangular. 
         [0030]    (5) The binding film  19  is formed on the walls of blind holes  15  and open area  17 . 
         [0031]    A binding agent is provided. The binding agent includes ethanol and silane coupling agent, wherein the mass ratio of the ethanol and the silane coupling agent is about (1-3):(97-99). The silane coupling agent may be 3-glycidyloxypropyltrimethoxysilane or amino silane coupling agent. 
         [0032]    The binding agent is sprayed on the walls of the open area  17  and blind holes  15 . Then, the main body  11  coated with the binding agent is baked at a temperature of about 80° C. to about 85° C. for about 30 min to about 40 min to form the binding film  19 . 
         [0033]    The conductive paint layer  21  is formed on the binding film  19 . 
         [0034]    The conductive paint layer  21  includes at least one type of conductive particles selected from the group consisting of Ag, Cu, C, and Au. In the exemplary embodiment, the conductive paint layer  21  includes Ag particles. 
         [0035]    The blind holes  15  with different sizes and/or shapes enhance the bond between the conductive paint layer  21  and the main body  11 . 
         [0036]    During the formation of the binding film  19 , the silane coupling agent is prone to hydrolysis and condensation to produce low polymer siloxane which contains Si—OH. When the binding agent adhesives to the surface of the main body  11 , the low polymer siloxane will react with metal ions (such as Ti 4+ , Ni 2+ , Cr 2+ , Al 3+ and Mg 2+ ) and form Si—O—M (M may be Ti, Ni, Cr, Al or Mg) groups, which enhances the bond between the binding film  19  and the main body  11 . The low polymer siloxane also reacts with organic resin included in the conductive paint layer  21 . Therefore, the binding film  19  can further enhance the bond between the conductive paint layer  21  and the main body  11 . 
         [0037]    It is to be understood, however, that even through numerous characteristics and advantages of the exemplary disclosure have been set forth in the foregoing description, together with details of the system and function of the disclosure, the disclosure is illustrative only, and changes may be made in detail, especially in the matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.