Patent Document

CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of U.S. Provisional Application Nos. 60/380,001, filed May 2, 2002, 60/378,188, filed May 6, 2002, and 60/391,134, filed Jun. 24, 2002, and is incorporated by reference.  
       CROSS REFERENCE TO CO-PENDING APPLICATIONS  
       [0002]    This application incorporates by reference the disclosures of each of the following co-pending applications which have been filed concurrently with this application: U.S. patent application Ser. No. ______, entitled “Mounting Bracket System,” filed May 2, 2003; U.S. patent application Ser. No. ______, entitled “Film Tensioning System,” filed May 2, 2003; U.S. patent application Ser. No. ______, entitled “Film Attaching System,” filed May 2, 2003; U.S. patent application Ser. No. ______, entitled “Electrical Connectors For Electro-Dynamic Loudspeakers,” filed May 2, 2003; U.S. patent application Ser. No. ______, entitled “Electro-Dynamic Loudspeaker Mounting System,” filed May 2, 2003; U.S. patent application Ser. No. ______, entitled “Frame Structure,” filed May 2, 2003; U.S. patent application Ser. No. ______, entitled “Acoustically Enhanced Electro-Dynamic Loudspeakers,” filed May 2, 2003; U.S. patent application Ser. No. ______, entitled “Directivity Control Of Electro-Dynamic Loudspeakers,” filed May 2, 2003; U.S. patent application Ser. No. ______, entitled “Frequency Response Enhancements For Electro-Dynamic Loudspeakers,” filed May 2, 2003; and U.S. patent application Ser. No. ______, entitled “Magnet Arrangement For Loudspeaker,” filed May 2, 2003. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0003]    1. Field of Invention.  
           [0004]    This invention relates to electro-dynamic loudspeakers, and more particularly to conductors used in electro-dynamic loudspeakers.  
           [0005]    2. Related Art.  
           [0006]    The general construction of an electro-dynamic loudspeaker includes a diaphragm, in the form of a thin film, attached in tension to a frame. An electrical circuit, in the form of electrically conductive traces, is applied to the surface of the diaphragm. Magnetic sources, typically in the form of permanent magnets, are mounted adjacent to the diaphragm or within the frame, creating a magnetic field. When current is flowing in the electrical circuit, the diaphragm vibrates in response to the interaction between the current and the magnetic field. The vibration of the diaphragm produces the sound generated by the electro-dynamic loudspeaker.  
           [0007]    Many design and manufacturing challenges present themselves in the manufacturing of electro-dynamic loudspeakers. First, the diaphragm, that is formed by a thin film, needs to be permanently attached, in tension, to the frame. Correct tension is required to optimize the resonance frequency of the diaphragm. Optimizing diaphragm resonance extends the bandwidth and reduces sound distortion of the loudspeaker.  
           [0008]    The diaphragm is driven by the motive force created when current passes through the conductor applied to the diaphragm within the magnetic field. The conductor on the electro-dynamic loudspeaker is attached directly to the diaphragm. Because the conductor is placed directly onto the thin diaphragm, the conductor should be constructed of a material having a low mass and should also be securely attached to the film at high power (large current) and high temperatures.  
           [0009]    Accordingly, designing conductors for electro-dynamic loudspeaker applications presents various challenges such as selecting the speaker with the desired audible output for a given location that will fit within the size and location constraints of the desired applications environment. Electro-dynamic loudspeakers exhibit a defined acoustical directivity pattern relative to each speaker&#39;s physical shape and the frequency of the audible output produced by each loudspeaker. Consequently, when an audio system is designed, loudspeakers possessing a desired directivity pattern over a given frequency range are selected to achieve the intended performance of the system. Different loudspeaker directivity patterns may be desirable for various loudspeaker applications. For example, for use in a consumer audio system for a home listening environment, a wide directivity may be preferred. In the application of a loudspeaker, a narrow directivity may be desirable to direct sound, e.g., voice, in a predetermined direction.  
           [0010]    Often, space limitations in the listening environment prohibit the use of a loudspeaker in an audio system that possesses the preferred directivity pattern for the system&#39;s design. For example, the amount of space and the particular locations available in a listening environment for locating and/or mounting the loudspeakers of the audio system may prohibit the use of a particular loudspeaker that exhibits the intended directivity pattern. Also, due to space and location constraints, it may not be possible to position or oriented the desired loudspeaker in a manner consistent with the loudspeaker&#39;s directivity pattern. Consequently, size and space constraints of a particular environment may make it difficult to achieve the desired performance from the audio system. An example of a listening environment having such constraints is the interior passenger compartment of an automobile or other vehicle.  
           [0011]    While the electric circuitry of electro-dynamic loudspeakers may present design challenges, electro-dynamic loudspeakers are very desirable loudspeakers because they are designed to have a very shallow depth. With this dimensional flexibility, electro-dynamic loudspeakers may be positioned at locations where conventional loudspeakers would not traditionally fit. This dimensional flexibility is particularly advantageous in automotive applications where positioning a loudspeaker at a location that a conventional loudspeaker would not otherwise fit could offer various advantages. Further, because the final loudspeaker assembly may be mounted on a vehicle, it is important that the assembly be rigid during shipping and handling so that the diaphragm or frame does not deform during installation.  
           [0012]    While conventional electro-dynamic loudspeakers are shallow in depth and may therefore be preferred over conventional loudspeakers for use in environments requiring thin loudspeakers, electro-dynamic loudspeakers have a generally rectangular planar radiator that is generally relatively large in height and width to achieve acceptable operating wavelength sensitivity, power handling, maximum sound pressure level capability and low-frequency bandwidth. Unfortunately, the large rectangular size results in a high-frequency beam width angle or coverage that may be too narrow for its intended application. The high-frequency horizontal and vertical coverage of a rectangular planar radiator is directly related to its width and height in an inverse relationship. As such, large radiator dimensions exhibit narrow high-frequency coverage and vice versa.  
           [0013]    The frame of the electro-dynamic loudspeakers supports the magnets, the diaphragm, and the terminal leads. A ferrous steel frame has the advantage of carrying magnetic flux that can improve efficiency over a non-ferrous frame. However, frames constructed from non-ferrous or non-metallic materials provide other manufacturing advantages. The frame presents design challenges since it is preferably rigid enough to keep the diaphragm film tension uniform and capable of not deforming during handling, assembly, or over time. The frame also should be capable of withstanding environmental high temperatures, humidity, salt, spray, etc., and be capable of bonding with the diaphragm film.  
           [0014]    Other features affecting the acoustic characteristics of the electro-dynamic loudspeaker include damping of undriven portions of the diaphragm film in order to help reduce distortion and smooth frequency response. Damping is required to control film edges by reducing unproductive vibration.  
           [0015]    Furthermore, the control directivity of sound is critical for a good system design and acoustical interaction in the listening environment. The electro-dynamic loudspeakers exhibit defined acoustical directivity relative to frequency and to their shape and also relative to the distance from the source. In addition, other frequency response enhancements can also be made to the current electro-dynamic loudspeaker designs.  
           [0016]    With the dimensional flexibility obtained with an electro-dynamic loudspeaker, various locations in automotive and non-automotive vehicles may be employed to house electro-dynamic loudspeakers. Different locations offer various advantages over other locations. The thin depth of the electro-dynamic loudspeaker allow them to fit where conventional loudspeakers would not. The final assembly may be mounted on a vehicle, and therefore, must be rigid during shipping and handling and should not allow the diaphragm or frame to deform during installation. The final assembly may be mounted on a vehicle, and therefore, must be rigid during shipping and handling and should not allow the diaphragm or frame to deform during installation.  
         SUMMARY  
         [0017]    This invention provides several conductor arrangements for electro-dynamic loudspeakers. In one arrangement, a wire conductor may be attached to the surface of a diaphragm of an electro-dynamic loudspeaker. A fixture including retractable spindles is provided for wrapping the wire conductor in specific pattern having a plurality of linear sections. The fixture is then placed adjacent to a film material and the retractable spindles are retracted so that the wire conductor is applied to the film material.  
           [0018]    In another arrangement, a conductor is attached to the surface of a diaphragm where the conductor is ribbon-shaped with a flat cross-section having a pair of side edges and a pair of relatively wide faces. The conductor may be attached to the diaphragm along one of the side edges so as to be suspended below one surface of the diaphragm and extend toward the magnets that are positioned and mounted to the frame.  
           [0019]    Another arrangement includes suspending the conductor below the upper edge surface of the frame while being supported on channels that are formed in the diaphragm. By suspending the conductors below the upper edge surface of the frame, the conductor traces are placed in closer proximity to the magnetic field generated by the magnets mounted to the frame.  
           [0020]    In an alternative arrangement an electrical conductor is formed by applying a layer of foil to a film material and laser etching the foil to remove portions of the foil in order to define a conductor having a plurality of linear sections.  
           [0021]    Also, an electrical conductor may be formed on the diaphragm by laser cutting the conductor material in order to form a plurality of linear sections from the material and applying the conductor to a film material.  
           [0022]    An electrical conductor may also be formed by applying a layer of foil to a film material utilizing an electron discharge machining technique for burning an image of electrode onto the surface of the film. The electrode would be formed as the desired shape of the areas of foil to be removed, thus leaving the remaining foil material in the desired shape of the conductor.  
           [0023]    An electrical conductor may also be formed by applying a mask over the foil in the desired shape of the conductor and the uncovered foil is then abrasively removed using known techniques such as water jet cutting using an abrasive slurry.  
           [0024]    Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]    The invention can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the different views  
         [0026]    [0026]FIG. 1 is a perspective view of an electro-dynamic loudspeaker.  
         [0027]    [0027]FIG. 2 is an exploded perspective view of the electro-dynamic loudspeaker shown in FIG. 1.  
         [0028]    [0028]FIG. 3 is a cross-sectional view taken along line  3 - 3  of FIG. 1.  
         [0029]    [0029]FIG. 4 is a detail cross-sectional view of the encircled area of FIG. 3.  
         [0030]    [0030]FIG. 5 is a plan view of the film having an attached conductor.  
         [0031]    [0031]FIG. 6 is a cross-sectional view of an electro-dynamic loudspeaker having an alternative embodiment employing a wire conductor.  
         [0032]    [0032]FIG. 7 is a detailed cross-sectional view of the encircled area of FIG. 6.  
         [0033]    [0033]FIG. 8 is a plan view of a fixture for forming the wire conductor.  
         [0034]    [0034]FIG. 9 is a perspective view of the fixture of FIG. 8 for forming the wire conductor.  
         [0035]    [0035]FIG. 10 is a detailed perspective view of the fixture of FIG. 8 for forming the wire conductor.  
         [0036]    [0036]FIG. 11 is a cross-sectional view of an electro-dynamic loudspeaker having a ribbon-shaped conductor mounted to an underside of the film.  
         [0037]    [0037]FIG. 12 is a detail cross-sectional view of the encircled area of FIG. 11.  
         [0038]    [0038]FIG. 13 is a cross-sectional view of an electro-dynamic loudspeaker having a film deformed to suspend the electrical traces downward towards the magnets.  
         [0039]    [0039]FIG. 14 is a flowchart illustrating the steps for forming an electrical conductor on a diaphragm by laser etching.  
         [0040]    [0040]FIG. 15 is a flowchart illustrating the steps of forming an electrical conductor by laser cutting the conductor from an aluminum foil and applying the conductor to a film.  
         [0041]    [0041]FIG. 16 is a perspective view illustrating attaching the conductor to the film.  
         [0042]    [0042]FIG. 17 is a cross-sectional view illustrating the magnetic field through the ribbon shaped conductors with caps provided on the magnets for focusing the magnetic field direction through the conductor traces.  
         [0043]    [0043]FIG. 18 is a cross-sectional view illustrating the magnetic field lines created by magnets having smaller caps.  
         [0044]    [0044]FIG. 19 is a schematic perspective view of an electron discharge machining process for forming an electrical conductor on a film.  
         [0045]    [0045]FIG. 20 is a schematic perspective view of an abrasive removing process for forming the electrical conductor on a film. 
     
    
     DETAILED DESCRIPTION  
       [0046]    [0046]FIG. 1 is a perspective view of an electro-dynamic loudspeaker  100  of the invention. As shown in FIG. 1, the electro-dynamic loudspeaker is a generally planar loudspeaker having a frame  102  with a diaphragm  104  attached in tension to the frame  102 . A conductor  106  is positioned on the diaphragm  104 . The conductor  106  is shaped in serpentine fashion having a plurality of substantially linear sections (or traces)  108  longitudinally extending along the diaphragm interconnected by radii  110  to form a single current path. Permanent magnets  202  (shown in FIG. 2) are positioned on the frame  102  underneath the diaphragm  104 , creating a magnetic field.  
         [0047]    Linear sections  108  are positioned within the flux fields generated by permanent magnets  202 . The linear sections  108  carry current in a first direction  112  and are positioned within magnetic flux fields having similar directional polarization. Linear sections  108  of conductor  106  having current flowing in a second direction  114 , that is opposite the first direction  112 , are placed within magnetic flux fields having an opposite directional polarization. Positioning the linear sections  108  in this manner assures that a driving force is generated by the interaction between the magnetic fields developed by magnets  202  and the magnetic fields developed by current flowing in conductor  106 . As such, an electrical input signal traveling through the conductor  106  causes the diaphragm  104  to move, thereby producing an acoustical output.  
         [0048]    [0048]FIG. 2 is an exploded perspective view of the electro-dynamic loudspeaker  100  shown in FIG. 1. As illustrated in FIG. 2, the flat panel loudspeaker  100  includes a frame  102 , a plurality of high energy magnets  202 , a diaphragm  104 , an acoustical dampener  236  and a grille  228 . Frame  102  provides a structure for fixing magnets  202  in a predetermined relationship to one another. In the depicted embodiment, magnets  202  are positioned to define five rows of magnets  202  with three magnets  202  in each row. The rows are arranged with alternating polarity such that fields of magnetic flux are created between each row. Once the flux fields have been defined, diaphragm  104  is fixed to frame  102  along its periphery.  
         [0049]    A conductor  106  is coupled to the diaphragm  104 . The conductor  106  is generally formed as an aluminum foil bonded to the diaphragm  104 . The conductor  106  can, however, be formed from other conductive materials. The conductor  106  has a first end  204  and a second end  206  positioned adjacent to one another at one end of the diaphragm  104 .  
         [0050]    As shown in FIG. 2, frame  102  is a generally dish-shaped member preferably constructed from a substantially planar contiguous steel sheet. The frame  102  includes a base plate  208  surrounded by a wall  210 . The wall  210  terminates at a radially extending flange  212 . The frame  102  further includes apertures  214  and  216  extending through flange  212  to provide clearance and mounting provisions for a conductor assembly  230 .  
         [0051]    Conductor assembly  230  includes a terminal board  218 , a first terminal  220  and a second terminal  222 . Terminal board  218  includes a mounting aperture  224  and is preferably constructed from an electrically insulating material such as plastic, fiberglass or other insulating material. A pair of rivets or other connectors (not shown) pass through apertures  214  to electrically couple first terminal  220  to first end  204  and second terminal  222  to second end  206  of conductor  106 . A fastener such as a rivet  226  extends through apertures  224  and  216  to couple conductor assembly  230  to frame  102 .  
         [0052]    A grille  228  functions to protect diaphragm  104  from contact with objects inside the listening environment while also providing a method for mounting loudspeaker  100 . The grille  228  has a substantially planar body  238  having a plurality of apertures  232  extending through the central portion of the planar body  238 . A rim  234  extends downward, substantially orthogonally from body  238 , along its perimeter and is designed to engage the frame  102  to couple the grille  228  to the frame  102 .  
         [0053]    An acoustical dampener  236  is mounted on the underside of the base plate  208  of the frame  102 . Dampener  236  serves to dissipate acoustical energy generated by diaphragm  104  thereby minimizing undesirable amplitude peaks during operation. The dampener  236  may be made of felt, or a similar gas permeable material.  
         [0054]    [0054]FIG. 3 is a cross-sectional view of the electro-dynamic loudspeaker taken along line  3 - 3  of FIG. 1. FIG. 3 shows the frame  102  having the diaphragm  104  attached in tension to the frame  102  and the permanent magnets  202  positioned on the frame  102  underneath the diaphragm  104 . Linear sections  108  of the conductor  106  are also shown positioned on top of the diaphragm  104 .  
         [0055]    [0055]FIG. 4 is an enlarged cross-sectional view of the encircled area of FIG. 3. As illustrated by FIG. 4, the diaphragm  104  is comprised of a thin film  400  having a first side  402  and a second side  404 . First side  402  is coupled to frame  102 . Generally, the diaphragm  104  is secured to the frame  102  by an adhesive  406  that is curable by exposure to radiation. However, the diaphragm  104  may secured to the frame  102  by other mechanism, such as those known in the art.  
         [0056]    To provide a movable membrane capable of producing sound, the diaphragm  104  is mounted to the frame  102  in a state of tension and spaced apart a predetermined distance from magnets  202 . The magnitude of tension of the diaphragm  104  depends on the speaker&#39;s physical dimensions, materials used to construct the diaphragm  104  and the strength of the magnetic field generated by magnets  202 . Magnets  202  are generally constructed from a highly energizable material such as neodymium iron boron (NdFeB), but may be made of other magnetic materials. The thin diaphragm film  400  is generally a polyethylenenaphthalate sheet having a thickness of approximately 0.001 inches; however, the diaphragm film  400  may be formed from materials such as polyester (e.g., known by the tradename “Mylar”), polyamide (e.g., known by the tradename “Kapton”) and polycarbonate (e.g., known by the tradename “Lexan”), and other materials known by those skilled in the art for forming diaphragms  104 .  
         [0057]    The conductor  106  is coupled to the second side  404  of the diaphragm film  400 . The conductor  106  is generally formed as an aluminum foil bonded to diaphragm film  400 , but may be formed of other conductive material known by those skilled in the art.  
         [0058]    The frame  102  includes a base plate  208  surrounded by a wall  210  extending generally orthogonally upward from the plate  208 . The wall  210  terminates at a radially extending flange  212  that defines a substantially planar mounting surface  414 . A lip  416  extends downwardly from flange  212  in a direction substantially parallel to wall  210 . Base plate  208  includes a first surface  418 , a second surface  420  and a plurality of apertures  422  extending through the base plate  208 . The apertures  422  are positioned and sized to provide air passageways between the first side  402  of diaphragm  104  and first surface  418  of frame  102 . An acoustical dampener  236  is mounted to second surface  420  of frame base plate  208 .  
         [0059]    Conductor  106 , as shown in FIG. 1, may be formed by bonding an aluminum foil to the film  400  and chemically etching away portions of the aluminum foil in order to define the linear sections  108  and radii  110  of the conductor  106 . Accordingly, it is desirable to provide additional methods of forming the conductor on a diaphragm of an electro-dynamic loudspeaker that is capable of carrying current, preferably has a low mass, and is permanently attached to the film even at high power and high temperature implementations.  
         [0060]    FIGS.  6 - 10  show the forming of a conductor  600  by attaching magnet wire  602  to the film  604 . The conductor  600 , which is comprised of magnet wire, may be arranged in a serpentine fashion and applied to the film  604  by an adhesive. As is the case with the electro-dynamic loudspeaker described above with reference to FIGS.  1 - 5 , the electro-dynamic loudspeaker  606  includes a frame  608  having a plurality of magnets  610  mounted therein as is described above. The film  604  is attached to the frame  608  by an adhesive  612 .  
         [0061]    In FIGS.  8 - 10 , a method for forming the magnet wire  602  in a serpentine configuration is shown, including a fixture  800  having a plurality of retractable spindles  802  around which the magnet wire  602  is wound in a serpentine pattern as illustrated in FIGS. 8 and 9. The fixture  800  includes an upper plate  900  and a retractable plate  902  to which the spindles  802  are fixedly connected. The spindles  802  pass through apertures provided in the upper plate  900 . After the magnet wire  602  is wound around the spindles  802 , the fixture  800  is disposed adjacent to a film material and the retractable plate  902  is moved away from the upper plate  900  so as to cause the spindles  802  to retract. Once the spindles  802  are retracted to the point that their extension is less than a diameter of the magnet wire  602 , the magnet wire  602  comes in contact with the film material. According to a preferred embodiment, the magnet wire  602  is coated with an adhesive which fixes the magnet wire  602  in the serpentine configuration to the film material. Optionally, a light can be shown through the film material in order to speed up the curing process of the adhesive that is applied to the magnet wire in order to more rapidly cure the adhesive. Once the adhesive is given appropriate time to cure, the spindles  802  are completely retracted so as to free the spindles from the magnet wire  602 . The spindles  802  can be formed of a self-lubricating material or can be highly polished, or both, in order to reduce the friction between the spindles  802  and the magnet wire  602 . In addition, the spindles  802  can be chemically treated to resist bonding with the adhesive applied to the magnet wire  602 . The conductor  600  can be applied to the film  400  either prior to or after the film has been mounted to the frame  102  of the electro-dynamic loudspeaker.  
         [0062]    In FIGS. 11 and 12, an electro-dynamic loudspeaker  1100  is provided with a conductor  1102  that is formed by ribbon-shaped wire  1104  which is provided with two narrow side edges  1200 ,  1202  and a pair of relatively wide faces  1204 ,  1206 . The ribbon-shaped conductor preferably extends below an upper attachment surface  1208  of the frame  1210 . By suspending the ribbon-shaped conductor below the upper attachment surface  1208  of the frame  1210 , the conductor  1102  extends towards the magnets  1212  so as to be closer to the magnetic field lines generated by the magnets  1212 . The ribbon-shaped conductor  1102  is attached to the film  1106  by an adhesive  1214  and can be formed in the same manner as the wire conductor  600  described above. In other words, the ribbon-shaped wire  1104  can be wrapped around a fixture such as that disclosed in FIGS.  8 - 10  (FIG. 10 shows the ribbon-shaped wire  1104 ) and applied to the film  1106  in the same manner as described above. By placing the ribbon-shaped conductor  1102  closer to the magnetic field, the intensity of the magnetic field lines are increased to allow a reduced strength magnet  1212  to be utilized which results in a cost savings for the manufacture of the electro-dynamic loudspeaker  1100 . Alternatively, the performance can be enhanced by taking advantage of the stronger magnetic flux density with the ribbon-shaped conductor being closer to the magnetic field.  
         [0063]    In FIG. 17, cap members  1700  can optionally be applied to the upper surface of the magnets  1212  in order to focus the magnetic field lines in a preferred direction relative to the conductor  1102 . Although the cap members are shown in combination with a ribbon-shaped conductor  1102 , the shape and configuration of the cap members  1700  can be varied in order to provide a desired magnetic field. As shown in FIG. 18, smaller caps  1800  permit a different shaped magnetic field for use with different configurations of conductors. The cap members  1700 ,  1800  are preferably made from a ferrous material and can be glued or otherwise held in place on the upper surface of the magnets  1212 .  
         [0064]    [0064]FIG. 13 illustrates an electro-dynamic loudspeaker  1300  having a diaphragm  1302  that has channels  1304  formed in the diaphragm  1302  and has electrical traces  1306  of a conductor  1308  disposed on opposite angularly disposed faces  1310 ,  1312  of the channels  1304 . The channels  1304  allow the traces  1306  to be suspended below an upper attachment surface  1314  of the frame  1316  so that the traces  1306  can be placed within the higher intensity magnetic field lines generated by the magnets  1318 . The film  1302  preferably has a thickness of between 2-5 mills in order to provide an appropriate rigidity for forming the channels  1304 . The channels  1304  are formed by placing the film  1302  in a heated mold provided with upper and lower die members provided with a channel-shaped protrusion in one die member and a channel-shaped recess in the other die member so as to permanently deform the film member  1302  into the configuration shown in FIG. 13. The film  1302  can be deformed prior to or after the conductor  1308  is applied thereto. The ability to place the conductor traces  1306  within the higher intensity magnetic field lines facilitates the use of weaker magnets than are typically required for an electro-dynamic loudspeaker. The reduced strength magnets  1318  therefore contribute to a lesser expensive electro-dynamic loudspeaker  1300 .  
         [0065]    [0065]FIG. 14 illustrates a flowchart of an alternative method for forming the conductor on the film of an electro-dynamic loudspeaker. At Step  1400 , an aluminum foil layer is applied to a film using an adhesive. At Step  1401 , a laser is utilized to etch away aluminum from the surface of the film in order to define the traces of the conductor. During the laser etching process, coolant fluid can be sprayed at the film material in order to cool the film material to prevent damage thereto due to the heat generated by the laser etching process. Lasers of this type are currently used to cut vias in printed circuit boards but have not been utilized for removing a conductive material from a laminate.  
         [0066]    [0066]FIGS. 15 and 16 illustrate an alternative method of forming the conductor where the conductor is laser cut from an aluminum foil in order to form flat traces  1600 . At Step  1501 , the conductor traces  1600  are applied to a film  1602 . Adhesive is applied to a surface of the aluminum foil prior to laser cutting and the adhesive is cured by passing selective bands of light through the film material  1602  in order to more rapidly cure the adhesive.  
         [0067]    [0067]FIG. 19 illustrates a method of forming an electrical conductor on a film is illustrated using an electron discharge machining (EDM) process. The film  1900  is provided with a layer of foil and an electrode plate  1902  having a face configuration with a void  1904  (shown in phantom in FIG. 19 on the underside of the plate  1902 ) in the desired shape of the electrical conductor. The electrode plate  1902  is brought in close proximity to the foil layer on the film  1900  and through a known “burning” process, an arc is formed from the electrode plate and “burns away” or otherwise removes the foil material so that the remaining foil is in the shape of the void  1904 , which is in the desired shape of the electrical conductor  1906 , as shown in FIG. 19. The electron discharge machining process is carried out with the electrode and workpiece immersed in a machining fluid which is a dielectric; i.e., an insulating medium. To generate a spark between the two parts, a voltage higher than the breakdown voltage of the gap is applied. This breakdown voltage depends on the distance between the two electrodes at their closest point, the insulating characteristic of the dielectric fluid, and the level of pollution in the gap.  
         [0068]    At the point in the gap where the electric field is strongest a discharge commences which then develops as follows:  
         [0069]    (a) Under the effect of the electric field, the free positive ions and electrons are accelerated, acquiring a high velocity and, very rapidly, they form an electrically-conductive ionized channel.  
         [0070]    (b) At this stage, current can pass through the channel. A spark is initiated between the electrodes and a plasma is formed. This rapidly attains a very high temperature, expanding under the effect of numerous impacts of charged particles and causing instantaneous local melting of material at the surface of both conductors.  
         [0071]    At the same time, due to vaporization of the electrodes and of the dielectric fluid, a gas bubble expands, and its pressure increases. At the moment the current is cut off, the gas bubble implodes due to the sudden fall of temperature, generating dynamic forces that results in melted material being ejected from the crater. This melted material is re-solidified in the dielectric fluid as small spheres and flushed away.  
         [0072]    [0072]FIG. 20 illustrates a method of forming an electrical conductor on a film is illustrated. In the process, a foil, such as aluminum, is applied to a film  2000 . A mask  2002  in the desired shape of a conductor is applied to the foil. An abrasive removing process is then employed to remove the foil in the unmasked areas. Preferably, a water jet device  2004  can be used with an abrasive slurry for abrading away the unmasked foil surface in order to leave the masked conductor shaped foil on the film  2000 . Other known abrasive and polishing type processes can also be employed for abrasively removing the foil from the unmasked areas.  
         [0073]    While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that other embodiments and implementations are possible that are within the scope of this invention. Accordingly, the invention is not restricted except in light of the attached claims and their equivalents.

Technology Category: 5