Abstract:
Disclosed is a flexible foil including a thin and flexible foil that isolates electromagnetic waves. The foil has a smooth surface and an opposite surface on which a plurality of three-dimensional raised projections is formed and consecutively lined up. A slicing-facilitated, flexible thinned layer is formed between adjacent ones of the projections. The foil can be deflected to enclose an electronic device that generates electromagnetic waves with the projections facing the electronic device so that the electromagnetic waves are confined inside the enclosure formed by the foil and dispersed and dissipated by reflection and diffraction in multiple angles caused by the projections so as to prevent leakage of electromagnetic waves and to protect electronic components close to the electromagnetic wave generating device from interference by the electromagnetic waves.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    (a) Technical Field of the Invention 
         [0002]    The present invention relates to a flexible foil which, can be used to enclose an electronic device that generates electromagnetic waves so as to effectively prevent leakage of electromagnetic waves. A method for manufacturing the foil is also provided. 
         [0003]    (b) Description of the Prior Art 
         [0004]    High-precision electronic components, such as semiconductor chips, for example a central processing unit (CPU), and a liquid crystal display (LCD), are often operated with low voltage and/or low current. These electronic components are often used in computers and control and operation systems of machines. However, these high-precision electronic devices that are operated with low voltage and low current are liable to electromagnetic interference by minor electromagnetic waves. Thus, it is necessary to isolate these electronic components from any electronic device that generates electromagnetic waves in order to eliminate interference with the operation of these high-precision electronic components by the electromagnetic waves. 
         [0005]      FIG. 1  of the attached drawings illustrates a conventional structure for isolating electromagnetic waves generated by an electronic device. In the example, the electronic device that generates electromagnetic waves comprises a rectifier  1 . A flat reflective foil  2 , preferably made of metal or comprising metallic material, is arranged to enclose the rectifier  1 . Due to reflection of electromagnetic wave by the metal foil  2 , electromagnetic waves generated by the rectifier  1  is confined within the enclosure formed by the foil  2  and is prevented from leakage out of the enclosure. However, the flat configuration of the foil  2  is not very effective in efficiently dispersing and dissipating the electromagnetic waves. Further, the reflective foil  2  is commonly made of metals, including gold, silver, and copper, which facilitates conduction and dissipation of heat so as to help dissipating heat generated by the rectifier  1 . 
         [0006]    Referring to  FIG. 2 , another application of the conventional foil  2  is shown. The foil  2  is attached to an object  3  from which heat generated thereby is to be dissipated. Examples of the object include a semiconductor chip, such as a central processing unit (CPU), a light-emitting diode or other lighting modules. The foil  2  can absorb heat generated by the object  3  and dissipates the heat to the surroundings through an opposite surface so as to regulate the temperature of the object  3 . However, since the opposite surface of the foil  2  through which heat is dissipated is flat, the effectiveness of heat dissipation is limited. 
         [0007]    Thus, it is desired to provide a foil that effectively dissipates electromagnetic wave and thermal energy so as to overcome the above drawbacks of the conventional foils. 
       SUMMARY OF THE INVENTION 
       [0008]    The primary purpose of the present invention is to The present invention relates to a flexible foil, which forms a plurality of three-dimensional raised projections and a slicing-facilitated flexible thinned layer formed between adjacent ones of the projections. The flexibility provided by the thinned layer allows the flexible foil to be deflected and enclosing an electronic device that generates electromagnetic waves with the projections facing the electronic device. The projections serve to reflect and diffract the electromagnetic waves in multiple angles so as to confine the electromagnetic waves inside the enclosure formed by the foil. The present invention also provides a method for manufacturing the flexible foil, comprising using rolling elements that are in continuous rotation to roll the foil so as to form the projections on one surface of the foil and then cutting the foil having the projections to desired sizes. 
         [0009]    An objective of the present invention is to provide a flexible foil that is deformable to enclose an electronic device that generates electromagnetic waves. The flexible foil forms projections on one surface thereof, which faces the electronic device when the foil encloses the electronic device, so that the projections serve to reflect and diffract the electromagnetic waves in multiple angles to dissipate and confine the electromagnetic waves inside the enclosure formed by the foil. Therefore, interference with high-precision electronic components by me electromagnetic waves from the electronic device is effectively prevented. 
         [0010]    Another objective of the present invention is to provide a flexible foil that features easy slicing and deflectability so as to allow the foil to be cut and deflect as desired. 
         [0011]    A further objective of the present invention is to provide a method that employs rollers to continuously roll a flexible foil and thus forming projections on one surface of the foil. The continuous rolling of the foil allows for mass and efficient production of the flexible foil and thus reducing the costs of the foil to enhance market competitivity. 
         [0012]    The foregoing object and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts. 
         [0013]    Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The present invention will be apparent to those skilled in the art by reading the following description of preferred embodiments thereof, with reference to the attached drawings, wherein: 
           [0015]      FIG. 1  is a schematic view showing an application of a conventional reflective foil; 
           [0016]      FIG. 2  is a schematic view showing another application of a conventional reflective foil; 
           [0017]      FIG. 3  is a perspective view of a flexible foil constructed in accordance with the present invention, wherein a portion of the foil is shown in enlarged scale to illustrate structural details thereof; 
           [0018]      FIG. 4  schematically shows a manufacturing process of the flexible foil of the present invention; 
           [0019]      FIG. 5  is a flow chart of the manufacturing process of the flexible foil of the present invention; 
           [0020]      FIG. 6  schematically shows an application of the flexible foil of the present invention; 
           [0021]      FIG. 7  shows a schematic side view illustrating an application of the flexible foil of the present invention; 
           [0022]      FIG. 8  schematically shows a computer system in which the flexible foil of the present invention is employed for electromagnetic interference protection; 
           [0023]      FIG. 9  schematically shows a machine comprising a controller which the flexible foil of the present invention is employed for electromagnetic interference protection; 
           [0024]      FIG. 10  is a perspective view illustrating cutting of the flexible foil of the present invention; 
           [0025]      FIG. 11  is a perspective view illustrating cutting the flexible foil of the present invention with a pair of scissors; 
           [0026]      FIG. 12  is a perspective view illustrating cutting the flexible foil of the present invention with a knife blade; 
           [0027]      FIG. 13  is a side elevational view illustrating an application of the flexible foil of the present invention in an object having a flat surface from which heat is to be removed; 
           [0028]      FIG. 14  is a side elevational view illustrating an application of the flexible foil of the present invention in an object having a curved surface from which heat is to be removed; 
           [0029]      FIG. 15  is an end view showing the flexible foils of the present invention are stored in a deflected and circled manner; 
           [0030]      FIG. 16  is an end view showing the flexible foil of the present invention is stored in a roll; 
           [0031]      FIG. 17  is a perspective view showing a modification of the flexible foil of the present invention in which an adhesive layer is coated on a smooth surface of the foil and a release film is attached to the adhesive layer; 
           [0032]      FIG. 18  is an enlarged view of a portion of the flexible foil showing conic projections formed on the flexible foil; 
           [0033]      FIG. 19  is an enlarged view of a portion of the flexible foil showing pyramid projections formed on the flexible foil; and 
           [0034]      FIG. 20  is an enlarged view of a portion of the flexible foil showing hemispheric or dome-shaped projections formed on the flexible foil. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0035]    The following descriptions are of exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims. 
         [0036]    With reference to the drawings and in particular to  FIG. 3 , a flexible foil constructed in accordance with the present invention, generally designated with reference numeral  4 , comprises a sheet of material having a smooth surface  41  and an opposite surface on which a plurality of raised projections  42  is formed and arranged in a matrix by consecutively lining up in columns and rows. The projections  42  are of a predetermined height, which in the embodiment illustrated is between 0.05-1.5 mm. A slicing-facilitated flexible thinned layer  43  is formed in a recessed portion (not labeled) between adjacent projections  42 . The thickness from the smooth surface  41  to the thinned layer  43  is between 0.02-0.4 mm. 
         [0037]    Also referring to  FIGS. 4 and 5 , a process for manufacturing the flexible foil  4  in accordance with the present invention will be described. The process comprises the following steps: Initially and as the first step, a length of foil-to-be-processed, generally designated with reference numeral  40 , is provided in the form of a roll of raw material. The second step is to provide rolling elements  5  for continuously forging the foil-to-be-processed  40 . The rolling elements  5  include a first roller  51  and a second roller  52 . The first roller  51  has a circumferential surface on which rolling teeth  511  are formed. The teeth  511  can be of a polygonal conic shape. The first and second rollers  51 ,  52  are positioned opposite to and in tight engagement with each other. Thus, when the foil-to-be-processed  40  is fed between the rollers  51 ,  52 , a substantial pressure is applied to the foil-to-be processed  40  by the rollers  51 ,  52 , which causes the teeth  511  of the first roller  51  to at least partially pierce into the surface of the foil-to-be-processed  40  facing and engaging the first roller  51 . The engagement between the rollers  51 ,  52  and the foil-to-be-processed  40  feeds the foil-to-be-processed  40  forward when the rollers  51 ,  52  rotate. Further, the teeth  511  of the first roller  51  piercing into the foil-to-be-processed  40  effectively form the projections  42  on the foil-to-be-processed  40  thereby providing a semi-product foil. 
         [0038]    Next, the semi-product foil is processed to release strain induced in the semi-product foil. The semi-product foil that has the projections  42  formed thereon is then subject to an optional surface treatment on the projection-formed surface thereof. Examples of the surface treatment include plating, quenching, and tempering, or a process of forming micro-structure on the surface. A further surface treatment, such as surface finishing or polishing, may be selectively performed on a smooth surface of the semi-product foil that is opposite to the projection-formed surface. 
         [0039]    Thereafter, slicing or cutting is carried out on the surface-treated and projection-formed semi-product foil  40  to provide flexible foils  4  of desired sizes; or alternatively, adhesive application is performed on the surface-treated and projection-formed semi-product foil  40 , in combination with slicing or cutting of the foil  40 . 
         [0040]      FIGS. 6-9  show different applications of the flexible foil  4  of the present invention. In the example shown in  FIG. 6 , the flexible foil  4  encloses an electronic device A that generates electromagnetic waves. The electronic device A can be any known device, such as a conventional rectifier illustrated in  FIG. 1 . The flexible foil  4  is arranged in such a way that the projections  42  of the foil  4  face the electronic device A whereby the projections  42  effect reflection and diffraction of electromagnetic wave in multiple angles inside the enclosure formed by the flexible foil  4 , and thus effectively preventing the electromagnetic wave from leaking outside the enclosure.  FIG. 7  illustrates in a more detailed manner how the projections  42  reflect and diffract the electromagnetic wave inside the enclosure formed by the foil  4 . The electromagnetic wave is confined inside the enclosure formed by the foil  4  and is then dispersed and dissipated. 
         [0041]      FIG. 8  shows an application of the flexible foil  4  in a computer system X in which an electronic device A that generates electromagnetic wave is arranged. The flexible foil  4  forms an enclosure surrounding tire electronic device A so as to protect a high-precision peripheral electronic component B that is also arranged inside the computer system X from being interfered with by the electromagnetic wave from the electronic device A.  FIG. 9  shows another application of the flexible foil  4  in a controller Y 1  and a man-machine interface Y 2  of a machine Y to prevent electromagnetic wave generated by an electronic device A that is incorporated in the controller Y 1  from interfering with the operation of a high-precision peripheral electronic component B that is also arranged inside the controller Y 1 . 
         [0042]      FIGS. 10 ,  11 , and  12  shows cutting the flexible foil  4  to a desired size, as indicated in  4 A. The cutting can be done with a pair of scissors C ( FIG. 11 ) or a knife blade D ( FIG. 12 ). 
         [0043]      FIGS. 13 and 14  show examples of practical use of the flexible foil  4 . In  FIG. 13 , the flexible foil  4  is attached to an object  3 , such as an object from which heat is to be dissipated, and this is done by applying a layer of adhesive  6  on the smooth surface  41  of that foil  4  that is opposite to the surface that forms the projections  42 . In the example of  FIG. 13 , the surface of the object  13  to which the foil  4  is attached is a flat surface. However, the surface to which the foil  4  is attached can be a curved surface or a curvature variable surface, as shown in  FIG. 14 , wherein the flexible foil  4 , due the flexibility thereof, is deflected and comply with the curved surface of the object  3 . Similarly, a layer of adhesive  6  is applied to the smooth surface  41  of the flexible foil  4  to attach the foil  4  to the object  3  with the projections  42  facing outward and away from the object  3 . Heat generated by the object  3  can be absorbed by the smooth surface  41  of the foil  4  that engages the object  3  and is further transferred to the projections  42  on the opposite surface of the foil  4  so as to allow the heat to be dissipated to the surroundings through the projections  42 . 
         [0044]    Referring to  FIGS. 15 and 16 , the flexible foil  4  that is manufactured in the way described above can be deflected in the form of a cylinder with an axially-extending slit so that a plurality of flexible foils  4  in the form of cylinder can be fit over each other as shown in  FIG. 15 . Alternatively as shown in  FIG. 16 , a length of the flexible foil  4  can be rolled up as a roll. Both facilitate storage and transportation of the flexible foil  4 . 
         [0045]      FIG. 17  shows a modification of the flexible foil  4  of the present invention, wherein an adhesive layer  6  is coated on the smooth surface  41  of the flexible foil  4  that is opposite to the surface that forms the projections  42 . A protective release film  61  is attached to the adhesive layer  6  and the release film  61  can be peeled off to expose the adhesive layer  6  for attaching to an object. 
         [0046]      FIGS. 18-20  show different structures of foe projections  42  formed on foe surface of foe flexible foil  4 . The projections  42  can be of any suitable shapes or structures and examples include a cone  44  ( FIG. 18 ), a pyramid  45  ( FIG. 19 ), or a triangular or quadrilateral cone, and a hemisphere or dome  46  ( FIG. 20 ) 
         [0047]    Apparently, the present invention provides a thin flexible foil  4 , which comprises a surface forming three-dimensional raised projections  42  that effectively reflect and diffract electromagnetic waves. The small thickness of the thin foil  4  allows for saving of material so that the present invention features both excellent isolation of electromagnetic waves and conservation of resources. 
         [0048]    Although the present invention has been described with reference to the preferred embodiments thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims. 
         [0049]    It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above. 
         [0050]    While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention.