BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a device shell for an electronic apparatus, for example, cellular telephone, PDA, LCD module or the like, and, more particularly, to an EMI protective device shell, which comprises a plastic shell body and a covering layer of aluminum foil bonded to the outside wall of the shell body for EMI (electromagnetic interference) protection.  
           [0002]    Various researches regarding the affect of the radiation of magnetic wave of a cellular telephone to human brain and human body have been reported. Related researches show the use causes temporary memory loss, headache, tiredness, deterioration of immunity, brain tumor, blood cancer, and etc. It is suggested not to closely attach the cellular telephone to the ear, or to attach a radiation shield to the cellular telephone when using it. The use of other electronic apparatus may also cause same problem. In order to eliminate the radiation of magnetic wave, electronic apparatus manufacturers may provide their electronic apparatus with a metal shield. However, the installation of the metal shield greatly increases the cost of the electronic apparatus. Furthermore, the metal shield cannot absolutely shields the electronic apparatus in all directions, i.e., the EMI protective effectiveness of the installation of a metal shield in an electronic apparatus is still not satisfactory.  
         SUMMARY OF THE INVENTION  
         [0003]    The present invention has been accomplished to provide an EMI protective device shell, which eliminates the aforesaid drawbacks. It is one object of the present invention to provide an EMI protective device shell, which effectively protects the internal circuit of the device against the interference of external noises and, shields the radiation of electromagnetic waves of the internal circuit of the device. It is another object of the present invention to provide an EMI protective device shell, which is inexpensive to manufacture. According to one aspect of the present invention, the EMI protective device shell comprises a plastic shell body for an electronic device, for example, a cellular telephone, PDA, LCD module, or the like, a covering layer of aluminum foil bonded to the smooth outside wall of the plastic shell body, and a layer of transparent protective coating spray-painted on the covering layer of aluminum foil. According to another aspect of the present invention, the covering layer of aluminum foil has a particular pattern or design obtained by means of a laser processing process. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0004]    [0004]FIG. 1 is an extended out view of a covering layer of aluminum foil for an EMI protective device shell according to the present invention.  
         [0005]    [0005]FIG. 2 is an exploded view of the plastic top cover shell and plastic bottom cover shell of a cellular telephone shell before the bonding of the respective covering layer of aluminum foil according to the present invention.  
         [0006]    [0006]FIG. 3 shows the plastic top cover shell and plastic bottom cover shell of the cellular telephone shell of FIG. 2 covered with a respective covering layer of aluminum foil according to the present invention.  
         [0007]    [0007]FIG. 4 is an assembly view of FIG. 3.  
         [0008]    [0008]FIG. 5 illustrates the shell of a camera covered with a covering layer of aluminum foil according to the present invention.  
         [0009]    [0009]FIG. 6 illustrates the shell of a PDA covered with a covering layer of aluminum foil according to the present invention.  
         [0010]    [0010]FIG. 7 illustrates the shell of a notebook computer covered with a covering layer of aluminum foil according to the present invention.  
         [0011]    [0011]FIG. 8 illustrates the shell of a LCD module covered with a covering layer of aluminum foil according to the present invention.  
         [0012]    [0012]FIG. 9A is a radiation chart obtained from a cellular telephone without the covering layer of aluminum foil.  
         [0013]    [0013]FIG. 9B is a radiation chart obtained from a cellular telephone with the covering layer of aluminum foil according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0014]    Referring to FIGS. from  1  through  4 , a cellular telephone  30  is shown comprising a cellular telephone shell  20 . The cellular telephone shell  20  is comprised of a plastic top cover shell  21  and a plastic bottom cover shell  22 . The plastic top cover shell  21  and the plastic bottom cover shell  22  have the respective outside wall covered with a respective covering layer of aluminum foil  10 . After adhesion to the outside wall of the plastic top cover shell  21  and the outside wall of the plastic bottom cover shell  22 , the adhesive which secures the respective covering layer of aluminum foil  10  to the plastic top cover shell  21  and the plastic bottom cover shell  22  is dried by heat. After drying of the adhesive, the covering of aluminum foil  10  of each of the plastic top cover shell  21  and the plastic bottom cover shell  22  is respectively coated with a layer of transparent protective coating by spray-painting. Because the plastic top cover shell  21  and plastic bottom cover shell  22  of the cellular telephone shell  20  of the cellular telephone  30  are covered with a respective covering layer of aluminum foil  10 , the cellular telephone shell  20  protects the internal circuit of the cellular telephone  30  against the interference of external noises and, shields the radiation of magnetic wave of the internal circuit of the cellular telephone  30  during its operation. Further, the covering layer of aluminum foil  10  for the plastic top cover shell  21  or plastic bottom cover shell  22  may be processed by laser to provide a pattern or design, so as to make the cellular telephone  30  more attractive and valuable. Because the top cover shell  21  and bottom cover shell  22  of the cellular telephone shell  20  are injection-molded from plastics and then covered with a respective covering layer of aluminum foil  10 , the manufacturing cost of the cellular telephone shell  20  is low.  
         [0015]    Referring to FIGS. 5 and 6, the shell of the camera  40  or PDA  50  has a covering layer of aluminum foil  10  adhered to the outside wall thereof and coated with a transparent protective layer of coating. The design of the covering layer of aluminum foil  10  makes the camera  40  or PDA  50  more attractive and valuable.  
         [0016]    Referring to FIGS. 7 and 8, the shell of the notebook computer  70  or LCD module  80  has a covering layer of aluminum foil  10  adhered to the outside wall of the shell thereof and coated with a transparent protective layer of coating. The design of the covering layer of aluminum foil  10  makes the camera  40  or PDA  50  more attractive and valuable. According to this embodiment, the shell of the computer  70  or LCD module  80  is injection-molded from plastics for the advantages of low weight and low manufacturing cost. The covering layer of aluminum foil  10  protects the internal circuit of the computer  70  or LCD module  80  against interference of external noises and, shields the radiation of magnetic wave of the internal circuit of the computer  70  or LCD module  80 .  
         [0017]    [0017]FIGS. 9A and 9B are radiation charts obtained from a cellular telephone without the covering layer of aluminum foil  10  and a cellular telephone with the covering layer of aluminum foil  10  respectively. As illustrated, the radiation of magnetic wave of the cellular telephone is attenuated and shielded by 60% after the installation of the covering layer of aluminum foil  10  of the present invention.  
         [0018]    A prototype of EMI protective device shell has been constructed with the features of FIGS.  1 ˜ 8 . The EMI protective device shell functions smoothly to provide all of the features discussed earlier.  
         [0019]    Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.
An EMI protective device shell having a covering layer of aluminum foil bonded to the smooth outside wall of the plastic shell body thereof and a layer of transparent protective coating spray-painted on the covering layer of aluminum foil.