Abstract:
A water-resistant cover consisting of three components: a soft, form-fitting shell, a plastic slider and a plastic end cap. The shell does not inhibit the functionality of peripheral controls and includes fully integrated polycarbonate windows that are thermally and mechanically bonded to the shell in the molding process, the windows being adapted to the specific contour and profile of the device and to protect the device&#39;s screen while not inhibiting the functionality of a touch-screen, keypad or acoustic devices. The slider is slidably connected to the cover for closing the audio jack aperture in the shell with a double closure to maintain a water-resistant seal when not in use. The end cap closes the cover with reciprocal seals that are molded into both components and the cap is easily removed for access to a data port or charger and is enhanced with water-resistant acoustic vents that provide sound clarity to speakers or microphones.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to covers for electronic devices and the process for the manufacture of the covers, and more specifically, to a process for the manufacture of covers in which a polycarbonate window is thermally bonded to a soft outer shell during the molding process, so as to obviate any possible delaminating of the window from the shell of the cover. 
     BACKGROUND OF THE INVENTION 
     With continued advances in technology, today&#39;s consumers find themselves with an ever increasing number of personal digital devices to choose from. These include cellular phones, “smart” phones, personal digital assistants (PDAs), portable GPS units, compact game systems, compact audio/video players and wireless reading devices. 
     While these electronic devices continue to improve, with an ever increasing list of features, they still suffer from a long-standing problem: their vulnerability to the elements, in particular dust and water. They are also susceptible to damage from general wear and tear, most noticeably the scratching or otherwise negatively impacting of the video screens. Protective covers have therefore been developed in order to protect these devices. 
     Most of the cases currently on the market are almost indistinguishable from a myriad of generic cases. They almost always offer face, side, and back protection for the encased electronic device, often including protection on the user interface (such as a click wheel or key pad), but leave the screen, switches, headphone ports, and charger ports or dock connector ports entirely exposed. Some models may include a screen protector that is applied as a separate component to the casing. As these screen protectors are not an incorporated component of the product, they will not protect against exposure to dust or moisture and are designed solely to protect the screen from scratching. 
     U.S. Pat. No. 5,896,453 teaches a flexible, plastic, waterproof enclosure wrapped around the circuitry of an electronic device (in this case a cellular phone) inside the phone housing. While providing water proofing for the device, it provides no protection to the screen. 
     U.S. Pat. No. 6,785,566 teaches an electronic device case comprised of a foam casing covered in vinyl having a transparent viewing window and hinged openings for the speaker and microphone. The case is designed to absorb impact and be waterproof and stain resistant. While suitable for the last generation of cellular phones having raised buttons, the foam case is large and cumbersome, running counter to the trend of small and streamlined electronic devices and not adapted for use with the touch screen devices available today. In addition, while a transparent window is provided with the case, the windows are not integrated or bonded to the case, and are therefore neither water nor dust resistant. 
     U.S. Pat. No. 7,312,984 teaches a number of protective case designs, all of which are rigid, hard-shell cases. A number of the protective cases are watertight, crush-resistant and impact-resistant. These cases have an outer shell in the form of an upper and a lower shell that are hingedly connected. A protective membrane is connected to the shell to allow a user to view, and use in the case of a touch screen, the device screen when the device is placed in the protective case. Adapters (for example, a head phone jack) may be disposed within the case for connecting to the device so that the user need only connect to the case, such that the protection afforded by the case is not affected. 
     While these devices provide significant protection for the electronic devices they are designed to carry, they are large and cumbersome, turning an elegant, svelte electronic device into a larger, plastic-covered device, and are relatively costly. In addition, the protective membrane is connected to the shell by way of an o-ring, which could lead to problems with water ingress should the o-ring become dislodged or otherwise improperly connected. An alternative embodiment teaches connecting the protective membrane to a protective foam which in turn is connected to the outer shell. Such a connection, presumably using an adhesive, could lead to delamination of the protective membrane from the protective foam and problems with water ingress. 
     None of the prior art cases offer a soft-shell, compact case with comprehensive protection with a fully enclosed screen that is video compatible at a price that is affordable for the average consumer. It is therefore an object of an embodiment of the present invention to provide a soft-shell electronic device cover that provides protection from dust and water but that is less costly and cumbersome than those taught in the prior art and a method for making same. 
     Other objects of embodiments of the invention will be apparent from the description that follows. 
     SUMMARY OF THE INVENTION 
     The present invention has solved the problems cited above utilizing a process whereby a thin polycarbonate window is thermally bonded to the soft outer shell of the cover during the injection molding process to create a water-resistant seal. An integrated window covers the lens portal on devices with cameras. The shell features a water-resistant acoustic vent over the earphone speaker aperture. To complete the water-resistant enclosure, a plastic slider with a dual seal was designed to close the audio jack aperture on both the inner and outer surfaces of the cover&#39;s shell and a plastic end cap featuring water-resistant acoustic vents closes the bottom of the cover with reciprocal seals that are molded into both the shell and end cap components. 
     According to one aspect of the present invention, there is provided a protective cover for an electronic device having a viewing screen. The cover comprises a shell and an end cap. The shell defines an enclosure with an opening at one end and has a shape corresponding to the shape of the electronic device for receiving the electronic device within the enclosure. The shell being formed of a soft, elastomeric material and having a protective membrane integrally connected to the soft shell, providing a viewing window through which the viewing screen may be viewed, and operated in the case of a touch screen device, when the electronic device is inserted into the shell. The rigid end cap is removably connectable to the open end of the soft sleeve to fully encase the electronic device when inserted into the shell. 
     The protective membrane has a plurality of perforations and is thermally and mechanically bonded to the shell. Preferably the shell is made of a thermoplastic elastomer or a thermoplastic rubber. The elastomer or rubber fills the plurality of perforations to form the mechanical bond. Preferably the protective membrane is a polycarbonate thermoplastic. 
     The protective cover may further comprise an aperture in the shell corresponding to an input area of the electronic device and an elongated guide slot in the shell adjacent to the aperture, the aperture being sealable by way of a rigid slider slidable within the guide slot from an open position wherein the aperture is open, to a closed position wherein the aperture is sealed. The slider closes the aperture with a double internal and external seal to maintain a water-resistant seal about the aperture when in the closed position. 
     The slider has an internal sealing element and an external sealing element joined by a central column. The slider further comprises a protrusion extending from the external sealing element, the protrusion inserting into the aperture when the slider is in the closed position. 
     According to another aspect of the present invention there is provided a method of manufacturing a protective cover for an electronic device having a viewing screen comprising the step of thermally and mechanically bonding a protective membrane to a soft outer shell. 
     The method further comprises the steps of: preparing a mold having a first portion and a second portion, the mold having a shape corresponding substantially to, and slightly larger than, the shape of said electronic device; positioning the protective membrane into the first portion, the protective membrane having a plurality of perforations about its outer edge; positioning a mandrel into the first portion adjacent the protective membrane, the mandrel shaped to correspond to the shape of the electronic device; connecting the second portion to the first portion thereby enclosing the protective membrane and mandrel within the mold; and injecting an elastomeric material into the mold, the elastomeric material surrounding the mandrel and thermally and mechanically bonding to the protective membrane. 
     Other aspects of the invention will be appreciated by reference to the detailed description of the preferred embodiment and to the claims that follow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings and wherein: 
         FIGS. 1 and 1   b  are perspective views from the front and back, respectively, of a cover for a personal digital device according to the present invention; 
         FIGS. 2   a  to  2   d  are perspective views of the cover shown in  FIG. 1  that illustrates the practical application of the plastic slider in the top of the cover which seals off the audio jack aperture; 
         FIG. 3   a  is a perspective view of the end cap for use with the cover; 
         FIG. 3   b  is a perspective view of the cover shown in  FIG. 1  that illustrates the plastic end cap that closes the cover with reciprocal seals that are molded into both the shell and the end cap of the cover; 
         FIG. 4   a  is a front plan view of the cover with the plastic slider shown in the closed position as shown in  FIG. 2   c;    
         FIG. 4   b  is a sectional view of the cover taken along the line  4   b - 4   b  shown in  FIG. 4   a  that illustrates the scope and the placement of the polycarbonate window; 
         FIG. 4   c  is a sectional view of Detail D shown in  FIG. 4   b;    
         FIG. 5  is a sectional view of the cover showing the front interior and that illustrates the design and placement of the polycarbonate window; 
         FIGS. 6   a  and  6   b  are perspective views of the manufacturing molds; 
         FIGS. 7   a ,  7   b , and  7   c  are perspective views of a stripper die mechanism; 
         FIG. 8   a  is a front plan view of the cover with the plastic slider shown in the closed position as shown in  FIG. 2   c    
         FIG. 8   b  is a cross-sectional view of a portion of the cover taken along the line  8 - 8  shown in  FIG. 8   a;    
         FIG. 9   a  is a front perspective view of the slider taken from the bottom left; 
         FIG. 9   b  is a front perspective view of the slider taken from the top left; 
         FIG. 9   c  is a left side view of the slider; and 
         FIG. 9   d  is a front view of the slider. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The preferred embodiment of an electronic device cover  1  is shown in  FIGS. 1-4 . The embodiment of the device cover  1  shown in the drawings corresponds to a specific electronic device  13 , however it is understood that the actual positioning and availability of the features of the cover discussed below can be customized for any electronic device. 
     Cover  1  comprises a soft, elastomeric shell  18 , having a front, back, sides, a closed end  29  and an open end  20  through which a device  13  can be inserted into the cover  1 . The thickness of the shell is preferably 0.787 inches (2 mm) thick which provides some shock absorption but maintains the svelte profile of the cover. Cover  1  has a fully integrated protective membrane  4  positioned so as to correspond to the position of the screen  17  of the device  13  to be placed in the cover. Protective membrane  4  is adapted to allow viewing of the device screen  17 , and use thereof in the case of touch screens. A water-resistant acoustic vent  28  covers the earphone speaker aperture  5 . As shown in  FIG. 1   b , the cover  1  also has a protective membrane  11  positioned to correspond to the position of the camera lens (not shown) of the device  13  when the device is properly inserted into the cover  1 . 
     The protective membranes  4 ,  11  are preferably made of a polycarbonate resin thermoplastic that is treated on both sides with a protective UV coating. Preferably during the making of the protective cover  1 , the protective membrane is also coated with an applied PVC registration membrane  16  and a protective vinyl mask  53  as discussed in more detail below. An example of a suitable polycarbonate resin thermoplastic is that marketed under the trademark LEXAN® made by SABIC Innovative Plastics. It is also contemplated that other materials such as acrylic and polyethylene terephthalate Glycol (PETG) or a polyester sheet such as Mylar® could be used to form the protective membrane. The protective membranes are thermally bonded to the soft, elastomeric shell  18  of the cover  1  in an injection molding process described below. 
     As shown best in  FIGS. 2   a - 2   d , the closed top of the cover  1  has an aperture  14  for an audio jack positioned to correspond to the audio jack aperture of the device  13 . Aperture  14  is preferably in the form of a single, o-ring profile which is molded into the cover to provide a water-resistant seal when an audio jack  12  is in use. The o-ring preferably has a diameter which is slightly smaller than the diameter of the plastic head  15  of the corresponding headphone audio jack so that when the headphone audio jack  12  is inserted into the aperture  14 , it forms a very tight seal thereby preventing water ingress. A portion of the plastic head  15  fits within the o-ring  14 , the soft, flexible elastomeric o-ring  14  deforming to allow the plastic head  15  to fit within it in a tight friction fit. 
     A rigid, plastic audio jack slider  2  in the top of the cover is slidable from an open position as shown in  FIGS. 2   a  and  2   b  to a closed position as shown in  FIG. 2   c .  FIG. 2   d  shows the audio jack slider  2  separated from the cover  1  in order to show the aperture  14  and corresponding elongated guide slot  19 . Audio jack slider  2  closes the audio jack aperture  14  with a double, internal and external seal to maintain a water-resistant seal in the closed position. 
     The double seal is best illustrated in  FIGS. 8 and 9   a  to  9   d . Slider  2  is preferably comprised of an internal  35  and external  36  sealing elements joined by a central column  39 . A protruding sealing element  37  sized to fit within aperture  14  and guide slot  19  projects downwards from the lower side of external sealing element  36 . Preferably the protruding sealing element  37  has curved leading and trailing edges and has straight sides, the width of which corresponds to the width of the guide slot  19 . When the slider  2  is positioned in the open position, protruding sealing element  37  is seated within the guide slot  19  forming a seal. When in the closed position, protruding sealing element  37  is seated in aperture  14 , the leading edge of the sealing element pushing on the soft edge of the o-ring causing it to deform so as to conform to the shape of the sealing element  37  thereby forming a seal. When in the closed position, aperture  14  is therefore blocked on the outside of the cover by external sealing element  36  (and sealing element  37 ) and on the inside by internal sealing element  35 . 
     As shown in  FIG. 8 , the slider is shaped to correspond to the shape of the cover  1 , such that external sealing element  36  is a planar element sitting on top of the cover and internal sealing element  35  is curved so as to form fit in contact with the device  13  when it is inserted into cover  1 . The slider  2  is inserted into elongated guide slot  19 , the soft elastomeric shell  18  derforming to allow the slider to be properly positioned within the slot  19 . Column  39  limits the movement of the slider within the guide slot  19  such that it is movable only between open and closed positions. When slided into the closed position, the internal  35  and external  36  sealing elements are in contact with the outer surface and inner surfaces of the o-ring aperture  14 . A series of laterally spaced indents  38  formed in the top surface of external seal  36  provide added grip for a user&#39;s thumb or finger when moving the slider between the open and closed positions. 
     A plastic end cap  3 , shown in  FIGS. 1 ,  3   a  and  3   b , is releasably connectable to the open end of shell  18  in order to fully enclose the device  13  after it has been inserted into shell  18 . Plastic end cap  3  has a series of rigid male and female profiles  7 . Cover  1  has a series of reciprocal, male and female profiles  6  that are molded into the interior of the soft, elastomeric shell  18  at the open end  20 . When end cap  3  is connected to cover  1  by insertion into open end  20  the reciprocal male and female profiles  6  and  7  interconnect thereby forming a seal—the rigidity of the end cap profiles  7  support the flexible profiles  6  of the soft, elastomeric shell  18 . Acoustic vents  9  and  28  (shown in  FIG. 1 ), are applied in the form of a decal to speaker apertures  8  which are formed in the injection molded end cap  3  and over the earphone speaker aperture  5 . The acoustic vents  9  and  28  allow sound to travel through the speaker apertures  8  and the earphone aperture  5 , while preventing the ingress of water into the cover. The end cap  3  has a protrusion  55  in its interior that has a gradient that corresponds to the position and the indentation of the device&#39;s home button  25  of the device so as to allow proper functioning of the home button. 
       FIGS. 4   a - c  illustrate specific aspects of the invention which include: the mechanically integrated audio jack slider  2  in the top of the cover which closes the audio jack aperture  14  from both the inner and outer surfaces of the case; the structure of the reciprocal seal profile  6  molded into the interior of the soft, elastomeric shell  18  at the open end  20 , the scope of the polycarbonate window  4  which is bonded to the inner surface of the cover and extends internally in the case to cover the aperture for the acoustic speaker  5  to provide a water-resistant seal without inhibiting sound quality; and the application of one layer of the PVC decal  16  on the exterior surface of the polycarbonate window  4  and of the protective vinyl mask  53  on the interior surface of the polycarbonate window  4 . 
     Each of the three main components—shell  18 , protective membranes  4 ,  11  and end cap  3  is form-fitted to the device for which it is designed, including the configurations of the device&#39;s peripheral buttons, apertures and screen. For example, device  13  shown in  FIGS. 1   a  and  1   b , has a ring/silent button  21 , a volume control  22 , a speaker  23 , a microphone  24 , a home button  25 , a telephone speaker  26 , a camera lens (not shown) and a power button (not shown). In order to allow proper functioning of these device features, the cover  1  has respective areas corresponding to the features, including elevated molded areas forming a ring/silent button  31 , a volume control button  32 , a power button  33  and, as shown in  FIG. 4 , a slightly indented area corresponding to the home button  10 , which itself is indented on the device  13 . The tolerance or thickness of the elastomeric shell around the peripheral controls is preferably reduced to a thickness of approximately 0.04 inches (1 mm) to allow greater ease in manipulating the controls. In addition, the cover has speaker apertures  8 , telephone speaker  5  and camera lens protective membrane  11 . The headphone aperture  14  and slider  2  have already been discussed in detail. 
     i. Equipment and Materials 
     The cover&#39;s windows  4 ,  11  are cut from a polycarbonate sheet on a die-cut machine to a predetermined size and shape corresponding to the part of the device to which they apply. Thin layers of polyvinyl chloride (PVC)  16  and a protective vinyl mask  53  are kiss-cut and applied to the polycarbonate windows as decals. The PVC decals are used to register the windows to an exact location of the window to the mold as discussed in more detail below. The PVC decals, preferably at a thickness of 0.03 inch thick each (0.762 mm), are pre-masked onto one side of the 0.01 inch (0.254 mm) polycarbonate window. Preferably, the protective vinyl mask is 1/64 inch (0.5 mm) thick and is applied to the polycarbonate window  4 , on the opposite side as the PVC decals. It is also contemplated that an adhesive paper or cling film could be used in place of the vinyl mask. 
     The decals are preferably adhered to within 0.118 of an inch (3 mm) from the edge of the windows  4 ,  11  so as to allow the windows  4 ,  11  to be bonded to the elastomeric shell  18 . 
     The shell  18  of the cover  1  is injection molded on a mandrel  49  in a mold formed of front and rear steel molds  43  and  44  shown in  FIGS. 6   a  and  6   b  and is preferably manufactured from a thermoplastic elastomer (TPE). It is also contemplated that a thermoplastic rubber (TPR) may also be used. The audio jack slider  2  and the end cap  3  are both injection molded in steel molds and are manufactured from polycarbonate Lexan 141-701. It is also contemplated that other suitable materials could be used, such as acrylonitrile butadiene styrene (ABS). 
     The water-resistant acoustic vent material  9  included in the end cap  3  covers the apertures  8  for the speaker  23  and microphone  24  from the inside of the end cap  3 . Preferably, acoustic vent material  9  is a microporous hydrophobic membrane such as that manufactured by W. L. Gore &amp; Associates, Inc. The membrane is die-cut and a water-resistant adhesive is applied annularly for adhesion of the acoustic vent material  9  to the apertures  8 . 
     An ejector shown in  FIGS. 7   a ,  7   b  and  7   c  is used to remove the newly formed cover  1  from the mandrel  49 . The ejector comprises an ultra high molecular weight (UHMW) polyethylene stripper die  50 , a pneumatic cylinder  51  and a base plate  52 . The pneumatic cylinder  51  is mounted on base plate  52 , which is preferably made of machined aluminum having two alignment pins (not shown) upon which the steel mandrel  49  can be mounted to hold it in place while the cover  1  is being removed. Stripper die  50  is preferably in the form of a machined block having a contact face  54  corresponding to the screen area for window  4  of the cover. The stripper die  50  is connected to the pneumatic cylinder  51  and is actionable in a reciprocating linear motion by the cylinder  51  in order to effect the de-molding of the cover  1  from the mandrel  49 . It is also contemplated that the cylinder  51  could be hydraulic or otherwise formed to be able to provide reciprocal linear motion. 
     ii. Process Steps 
     The molding process of the present invention described herein will be illustrated by a cover for a branded cellular telephone that features a touch-screen and an internal camera; although it will be understood that the process steps are equally applicable to the manufacture of other covers having configurations which suit the personal digital devices of various brands. 
     The TPE is thermally bonded to the polycarbonate windows  4 ,  11  during the injection molding process.  FIG. 5  illustrates how a further mechanical adhesion is included, whereby the edges of the polycarbonate window  4  are perforated with small, preferably 0.06 inch (1.5 mm), holes  48  in the die-cutting phase to allow the TPE to flow though the polycarbonate membrane to create an even stronger bond between the cover&#39;s shell and window. The combination of thermal and mechanical bonding of the polycarbonate membrane  4  to the shell  18  ensures that no delamination will occur. The polycarbonate window  4  also extends to cover two openings for sensors  47  so as to allow the phone&#39;s screen to go into power saving mode when held to the ear. The protective vinyl mask  53  protects the polycarbonate window from scratching during the molding process. 
       FIGS. 6   a  and  6   b  illustrate the placement of the layered polycarbonate window  4 , having the applied PVC decal  16  into the registration cavity  45  of the mold  43  where they are registered prior to the injection cycle. To assure the consistent placement and alignment of the windows onto the mandrel  49  of the mold, the windows are secured in place throughout the injection molding cycle by the outer edge of the PVC decal  16  which is sized to fit within the confines of the registration cavity  45  defined by perimeter wall  42 . Once properly aligned within the registration cavity  45 , the window  4  is held in place by way of vacuum pressure inside the registration cavity which is created by a vacuum port  46  that is machined through the surface of cavity  45  into the core of the mold  43 . While it is not shown in the drawings, there is also a corresponding vacuum port and registration cavity in mold  44  for registering the camera lens protective membrane  11 . It is understood that a similar process is followed for protective membrane  11 . 
     Preferably, as shown in  FIG. 6   b , two placement pins  41  are machined into the mandrel  49  so as to further align the window prior to the mold closing for the molding process. Preferably, the cavity of the mold  45  and the mandrel  49  are coated with a non-stick coating such as that sold under the trademark Nibore®. It is also contemplated that other similar products having non-stick characteristics such as that sold under the Trademark Teflon® may be used. 
       FIGS. 7   a ,  7   b  and  7   c  illustrate the removal of the cover from the mandrel  49  upon the completion of the injection cycle. The front and rear molds  43 ,  44  are separated from one another and the mandrel  49  of the mold, with the integrated shell  18  and windows  4 ,  11  intact, is removed from the mold and placed in the ejector. The mandrel  49  is placed on the alignment pins on the plate  52  and the stripper die is positioned so that contact face  54  is fitted in contact with the window  4  (coated with the PVC decal  16 ) within the boundary defining the window within the elastomeric shell  18 . Stripper die  50  pneumatically removes the cover  1  from the mandrel  49  of the mold using shear force that is generated by the cylinder  51 . The stripper die  50  allows the cover  1  to be easily removed from the mandrel  49  so as not to compromise the tolerance of the profile of the soft TPE cover. 
     As discussed above, acoustic vents  9  and  28 , manufactured from a water-resistant membrane, are applied in the form of an adhesive decal to the speaker apertures  8  on the inner side of the injection molded end cap  3  and the earphone aperture  5  in the shell  18  of the cover. 
     The injection molded audio jack slider  2  and end cap  3  are manually attached to the shell to complete the assembly of the water-resistant cover. The PVC decals  16  and the protective vinyl mask  53  are removed following assembly. 
     It will be appreciated by those skilled in the art that the preferred and alternative embodiments have been described in some detail but that certain modifications may be practiced without departing from the principles of the invention.