Abstract:
An electromagnetic shield includes a conductive foam, a plurality of adhesive tapes attached to a side of the conductive foam. The adhesive tapes are separated from each other. An electronic device using the electromagnetic shield to block electromagnetic energy from inner component or outer component is also provided.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The present invention generally relates to electromagnetic interferences, and particularly to an electromagnetic shield for an electronic device. 
         [0003]    2. Description of Related Art 
         [0004]    Electronic devices radiate and may also be affected by electromagnetic waves in their surrounding environment. Therefore, electronic devices adopt electromagnetic shields to block electromagnetic waves from radiating out of and into the electronic devices from outside sources. Typically, conductive foam is commonly used as a screen to block the electromagnetic waves. 
         [0005]    Referring to  FIG. 10 , an electromagnetic shield consists of a conductive foam  1  and an adhesive tape  2 . The adhesive tape  2  is also conductive and attached to one side of the conductive foam  1 . In practice, the electromagnetic shield is fixed appropriately on the electronic device, such as peripheral places around circuit modules or I/O ports, via the adhesive tape  2 . The electromagnetic shield not only blocks the electromagnetic energy, but also conducts static electricity from the circuit modules or the I/O ports to outside of the shield. 
         [0006]    However, a resistivity of the adhesive tape  2  is higher than that of the conductive foam  1 , as a result, the electromagnetic shield has poor electrical conductivity. Therefore, the electromagnetic shield has a low efficiency in blocking the electromagnetic energy due to the electrically poor conductivity. 
         [0007]    Therefore, improvements for the electromagnetic shield are needed in the industry to address the aforementioned deficiency. 
       SUMMARY 
       [0008]    An electromagnetic shield includes a conductive foam, a plurality of adhesive tapes attached to a side of the conductive foam. The adhesive tapes are separated from each other. An electronic device using the electromagnetic shield to block electromagnetic energy from inner component or outer component is also provided. 
         [0009]    Other advantages and novel features of the present invention will become more apparent from the following detailed description of preferred embodiment when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a cross-sectional view of an electromagnetic shield in accordance with a first exemplary embodiment. 
           [0011]      FIG. 2  is a bottom plan view of the electromagnetic shield of  FIG. 1 . 
           [0012]      FIG. 3  is a bottom plan view of an electromagnetic shield in accordance with a second exemplary embodiment. 
           [0013]      FIG. 4  is a bottom plan view of an electromagnetic shield in accordance with a third exemplary embodiment. 
           [0014]      FIG. 5  is a disassembled schematic diagram showing a notebook computer using the electromagnetic shield of  FIG. 1 , the electromagnetic shield disposed under a mainboard of the notebook computer. 
           [0015]      FIG. 6  is an assembled schematic diagram showing the notebook computer of  FIG. 5 . 
           [0016]      FIG. 7  is a disassembled schematic diagram showing the notebook computer using the electromagnetic shield of  FIG. 1 , the electromagnetic shield disposed between a connector and the notebook computer. 
           [0017]      FIG. 8  is an assembled schematic diagram showing the notebook computer of  FIG. 7 . 
           [0018]      FIG. 9  is cross-sectional view of the notebook computer along a line XI-XI in  FIG. 8 . 
           [0019]      FIG. 10  is a cross-sectional view of a conventional electromagnetic shield. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Reference will now be made to the drawings to describe a preferred embodiment of the present electromagnetic shield, and a preferred embodiment of the present electronic device. 
         [0021]    Referring to  FIGS. 1-2 , an electromagnetic shield  200  in accordance with a first embodiment is illustrated. The electromagnetic shield  200  includes a conductive foam  10  and a plurality of adhesive tapes  20 . The adhesive tapes  20  are attached to a side of the conductive foam  10 , and are aligned and separated from each other at a uniform distance. A plurality of gaps  30  is defined between the adhesive tapes  20 . 
         [0022]    The conductive foam  10  includes a foam  12  packed in a conductive coat  14 . The conductive coat  14  is made of metallic foils, such as aluminum foil, silver foil, and so on. The foam  12  and the conductive coat  14  cooperatively provide flexibility and electrical conductivity. 
         [0023]    Each adhesive tape  20  is an electric bond, such as electric glue, including a bond body  22  and metallic grains  24  dispersed in the bond body  22 . The bond body  22  is made of adhesive materials such as adhesive resin. The metallic grains  24  are made of silver, copper, etc. When the adhesive tape  20  is pressed, the metallic grains  24  becomes in contact with each other. The electric conductivity of the adhesive tape  20  depends on the metallic grains  24  contacting each other. 
         [0024]    Referring to  FIG. 3 , in another embodiment, the adhesive tapes  20  are separated from each other at various distances on the conductive foam  10 . Referring to  FIG. 4 , the adhesive tapes  20  can also be obliquely aligned on the conductive foam  10  with respect to an edge of the conductive foam  10  and separated at a uniform distance. Moreover, the adhesive tapes  20  can also be aligned in other forms as long as gaps are defined between the adhesive tapes  20 . 
         [0025]    When the electromagnetic shield  200  is fixed into a position in an electronic device, the adhesive tapes  20  attaches the conductive foam  10  to the position in the electronic device, the conductive foam  10  partially deforms and fills the gaps  30  between the adhesive tapes  20 . Thereby, the conductive foam  10  is in direct contact with the position. Therefore, an electric conductivity of the electromagnetic shield  200  is improved, and the electromagnetic shield  200  obtains a comparative shielding efficiency (see  FIG. 6 ). 
         [0026]    The electromagnetic shield  200  can be widely used in various electronic devices. For example, also referring to  FIGS. 5-6 , the electromagnetic shield  200  is used to block electromagnetic energy and conduct static electricity in a notebook computer  50 . The notebook computer  50  includes a housing  52  and a mainboard  54 . The mainboard  54  is attached onto the housing  52  via screws  56 . The electromagnetic shield  200  is fixed between the housing  52  and the mainboard  54 . 
         [0027]    In assembly, the adhesive tapes  20  attaches to the housing  52 , and the mainboard  54  is disposed on the conductive foam  10 . The screws  56  pass through the mainboard  54  and fasten the mainboard  54  tightly onto the housing  52 . In this manner, the conductive foam  10  is pressed by the mainboard  54  toward the housing  52 . Consequently, the conductive foam  10  partially deforms and fills the gaps  30  between the adhesive tapes  20 . Thereby, the conductive foam  10  is in direct contact with the housing  52 . Therefore, static electricity can be conducted from the mainboard  54  to the housing  52 , and electromagnetic energy can be blocked from interfering with the circuitry of the mainboard  54 . 
         [0028]    Furthermore, the notebook computer  50  also includes I/O ports to connect to other peripheral devices, such as keyboards, mice, printers, and so on. Referring to  FIGS. 7-9 , the notebook computer  50  defines an I/O port  60  therein without showing detailed structure of the I/O port  60 . The I/O port  60  is configured for receiving connectors, such as RS232 connector, USB connector, and so on. In the embodiment, a connector  62  is configured for cooperatively establishing an electrical connection with the I/O port  60 . The electromagnetic shield  200  is disposed between the I/O port  60  and the connector  62 . 
         [0029]    The I/O port  60  defines a receiving hole therein, and correspondingly the electromagnetic shield  200  also defines a through hole therein. The connector  62  includes a base  622  and a connection portion  620  formed on a side of the base  622 . Herein, the connector  62  is shown for illustrative purposes but can also be connected to other peripheral devices, such as printers, scanners, and so on, via an electric wire. 
         [0030]    In assembly, the electromagnetic shield  200  is attached to peripheral edges of the I/O port  60 . The adhesive tapes  20  attaches to the peripheral edges. The connection portion  620  passes through the through hole of the electromagnetic shield  200 , and is received in the receiving hole of the I/O port  60 . The base  622  presses the electromagnetic shield  200  toward the I/O port  60 . The conductive foam  10  partially deforms and fills the gaps  30  between the adhesive tapes  20 , thereby, the conductive foam  10  is in direct contact with the peripheral edges of the I/O port  60 . Therefore, the electromagnetic shield  200  can block electromagnetic energy from entering into the notebook computer  50  through the I/O port  60 . 
         [0031]    It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.