Abstract:
A chemically resistant protective cover for an electronic device that has an interactive control panel includes a protective shell having a first member and a second member. The second member is configured to join with the first case. An aperture defined by the protective shell aligns with the interactive control panel. A chemically resistant protective membrane for an electronic device includes a sheet of engineered thermoplastic having dimensions corresponding to features of a surface of the electronic device, and has a combination of sufficient thinness and a dielectric constant that together permit capacitive inputs on a front side of the protective membrane to be transmitted to the capacitance sensing interactive control panel.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 12/560,621 filed Sep. 16, 2009, which is a continuation of U.S. patent application Ser. No. 11/456,157, filed Jul. 7, 2006 (now U.S. Pat. No. 7,609,512), which application is in turn a continuation-in-part of U.S. patent application Ser. No. 10/937,048, filed Sep. 8, 2004 (now U.S. Pat. No. 7,158,376). U.S. patent application Ser. No. 10/937,048 is a continuation-in-part of U.S. patent application Ser. No. 10/645,439, filed Aug. 20, 2003 (now U.S. Pat. No. 6,995,976). U.S. patent application Ser. No. 10/645,439 is a continuation of U.S. patent application Ser. No. 10/300,200, filed Nov. 19, 2002 (now U.S. Pat. No. 6,646,864) which claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 60/335,865 filed Nov. 19, 2001. The entire contents of the above mentioned applications are hereby specifically incorporated herein by reference for all they disclose and teach. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Portable electronic devices (PEDs), such as PDAs, computers, MP3 players, music players, video players, smart phones, GPS receivers, telematics devices, cell phones, satellite phones, pagers, monitors, etc., are being very widely used, and are being deployed in industrial as well as office environments. PEDs are being used in industrial environments for data collection, such as service information on an airplane, or for data delivery such as maps for fire fighters and other emergency personnel. When PEDs are deployed in such industrial applications, the data that is collected and displayed on the PED can be extremely valuable and can be lifesaving. 
         [0003]    The industrial environments impose harsh conditions that typical PEDs are not designed to accommodate. For example, damage can be done to the PED through rough handling and dropping. Further, industrial chemicals, grease, water, dirt, and grime may damage or destroy a functioning PED and inhibit the use of the PEDs valuable data. 
         [0004]    It is common to hold the PEDs inside a protective case for transport. However, PEDs are usually removed for use since most cases used for transport are not interactive. Interactive cases are also useful for non-industrial applications to provide protection for PEDs. 
       SUMMARY OF THE INVENTION 
       [0005]    A protection system for an electronic device having an interactive control panel includes a chemically resistant protective cover having a protective shell, an aperture defined by the protective shell, and a chemically resistant additive provided to at least part of the protective shell. The protection system also includes a chemically resistant protective membrane including a sheet of engineered thermoplastic that includes the chemically resistant additive. The protective shell is crush-resistant and has top and bottom portions. The top portion has inner and outer surfaces, and the protective shell is formed to cover at least part of the electronic device when the electronic device is disposed in the protective shell. The aperture is formed to be aligned so as to expose at least the interactive control panel when the electronic device is at least partially covered by the protective shell. The chemically resistive additive provides chemical resistance to at least part of the protective shell. 
         [0006]    In disclosed implementations the chemically resistant additive may include metal flakes, which may be provided to the top and/or bottom portions of the protective shell of the protective cover, and/or to the protective membrane. 
         [0007]    In disclosed implementations the chemically resistant additive includes a metallized coating on the top and/or bottom portions of chemically resistant protective cover and/or on the chemically resistant protective membrane. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    In the drawings, 
           [0009]      FIG. 1  is a perspective view of an embodiment of the invention shown in the closed position. 
           [0010]      FIG. 2  is a perspective view of an embodiment of the invention shown in the open position. 
           [0011]      FIG. 3  is a perspective view of an embodiment of the invention shown in an exploded state. 
           [0012]      FIG. 4  is a perspective view of an embodiment of the invention shown from the rear. 
           [0013]      FIG. 5  is a front view of an embodiment of the invention, showing a section line. 
           [0014]      FIG. 6  is a section view of an embodiment of the invention. 
           [0015]      FIG. 7  is a detailed view of a section shown in  FIG. 6 . 
           [0016]      FIG. 8  is a perspective view of another embodiment comprising a single piece encapsulating cover. 
           [0017]      FIG. 9  is a perspective view of a third embodiment comprising a non-encapsulating snap over cover. 
           [0018]      FIG. 10  is a perspective view of an embodiment that comprises a belt clip. 
           [0019]      FIG. 11  is a second perspective view of an embodiment that comprises a belt clip. 
           [0020]      FIG. 12  is a perspective view of another embodiment of the present invention of a protective cover for a PED or other device. 
           [0021]      FIG. 13A  is a perspective top view of another embodiment of a protective enclosure for a tablet PC. 
           [0022]      FIG. 13B  is a view of the protective enclosure lid of  FIG. 13A . 
           [0023]      FIG. 14  is a perspective top view of the embodiment of  FIG. 13A  with an open lid. 
           [0024]      FIG. 15  is a perspective bottom view of the embodiment of  FIG. 13A . 
           [0025]      FIG. 16  is a perspective view of the base of the embodiment of  FIG. 13A   
           [0026]      FIG. 17  is an exploded view of an embodiment of a protective enclosure for an interactive flat-panel controlled device. 
           [0027]      FIG. 18  is an exploded view of another embodiment of a protective enclosure for an interactive flat-panel controlled device. 
           [0028]      FIG. 19  is an exploded view of another embodiment of a protective enclosure with an open lid for a laptop computer device. 
           [0029]      FIG. 20  is an exploded view of a protective enclosure with an open lid for a laptop computer device positioned inside the enclosure. 
           [0030]      FIG. 21  is a perspective top view of a protective enclosure with a closed lid for a laptop computer device. 
           [0031]      FIG. 22  is a perspective bottom view of the protective enclosure  FIG. 21 . 
           [0032]      FIG. 23  is a perspective front view of the embodiment of  FIG. 21 . 
           [0033]      FIG. 24  is a perspective end view of the embodiment of  FIG. 21 . 
           [0034]      FIG. 25  is a perspective back view of the embodiment of  FIG. 21 . 
           [0035]      FIG. 26  is a perspective view of the USB hub. 
           [0036]      FIG. 27  is a perspective view of the USB hub mounted inside the enclosure of FIG. 
           [0037]      FIG. 28  is a perspective view of the USB hub mounted inside the enclosure of  FIG. 14 . 
       
    
    
     DETAILED DESCRIPTION 
       [0038]      FIG. 1  is a perspective view of an embodiment of the invention. Embodiment  100  comprises a rigidly molded front case  102  and rear case  104 . An overmolded grommet  106  forms a receptacle for stylus  108  and also aids in sealing membrane  110 . A flexible hand strap  112  attaches to the rear case  104 . A hinge  114  joins front case  102  and rear case  104 . A ring  124  for a lanyard is shown as an integral feature of rear case  104 . 
         [0039]    Embodiment  100  is designed to hold a conventional personal digital assistant (PED) in a protective case. A PED, such as a Palm Pilot, Handspring Visor, Compaq Ipaq, Hewlett Packard Jornada, or similar products, use a touch screen for display and data entry. The touch screen display comprises either a color or black and white liquid crystal display with a touch sensitive device mounted on top of the display. The display is used for displaying graphics, text, and other elements to the user. The touch screen is used with a stylus  108  to select elements from the screen, to draw figures, and to enter text with a character recognition program in the PED. The stylus  108  generally resembles a conventional writing implement. However, the tip of the writing implement is a rounded plastic tip. In place of a stylus  108 , the user may use the tip of a finger or fingernail, or a conventional pen or pencil. When a conventional writing implement is used, damage to the touch screen element may occur, such as scratches. 
         [0040]    For the purposes of this specification, the term PED shall include any electronic device that has a touch screen interface. This may include instruments such as voltmeters, oscilloscopes, logic analyzers, and any other hand held, bench top, or rack mounted instrument that has a touch screen interface. Hand held devices, such as cell phones, satellite phones, telemetric devices, and other hand held devices are also to be classified as PEDs for the purposes of this specification. The term PED shall also include any computer terminal display that has a touch screen interface. These may comprise kiosks, outdoor terminal interfaces, industrial computer interfaces, commercial computer interfaces, and other computer displays. Additionally, the term PED may comprise barcode scanners, hand held GPS receivers, and other handheld electronic devices. The foregoing description of the term PED has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed, and other modifications and variations may be possible in light of the teachings of this specification. 
         [0041]    In addition, the PEDs typically have a handful of additional buttons as part of the user interface. These buttons are generally on the front of the device, near the touch screen element. The additional buttons may be used as shortcut buttons to instantly call up a certain program on the PED, may comprise a method of scrolling, may be used to select items from a list, or may have any function that the designer of the PED software may assign to the button or set of buttons. The button size, layout, and function may vary for each manufacturer and model of PED. 
         [0042]    Further, PEDs typically have at least one method of connecting to another computer. This may be through a direct electrical connection, such as through a wire cable or fiber optic, or through another medium such as infrared communication or through a radio communication. 
         [0043]    Additionally, the PEDs typically have an electrical source. The electrical source may be a rechargeable or non-rechargeable battery or solar cells. The electrical source may be a remote source of electricity that is transmitted to the PED through a wire cable or through other methods of electrical transmission. 
         [0044]    Further, PEDs may have indicator lights, such as status lights for power, communication, battery status, or other functions. The lights may be located on any of the sides of the PED and may be viewable on one or more sides. 
         [0045]    Front case  102  and rear case  104  form a protective cover for the PED. The protective cover may be designed for rugged industrial use, recreational use, commercial use, or many other uses. An industrial use may require the protective cover to be watertight, chemically resistant, protect the unit when dropped, and be crush proof. A typical application may be for fire fighters to use a PED for a display of maps for directions to an emergency scene or for a building plan at the scene of a fire. Another example may be a maintenance mechanic in a chemical plant using a PED to record maintenance records in the plant that processes. A recreational use may require the cover to be watertight, afford some protection against dropping and being crushed, float in water, and be dust resistant. A recreational use may be to take the PED during kayaking, diving, or other water sport activity. Further, the case may be used when the PED is taken camping, hiking, or other outdoor activity. A commercial use may additionally require the protective cover to be elegant, but may also require the cover to be replaceable so that scratches and other signs of wear and tear can be easily and cheaply replaced. 
         [0046]    The protective cover for the PED may take on many embodiments. The embodiment  100  comprises a front case  102  and rear case  104  that are joined by a hinge  114  and a clasp mechanism that is on the side of the cases opposite the hinge  114 . Other embodiments may have a small door into which the PED slides, or the protective cover may not completely enclose the PED and only cover the face where the user interface exists, leaving one or more sides of the PED exposed. Those skilled in the art may use other designs of protective covers without deviating from the scope and intent of the present invention. 
         [0047]    The protective cover may be constructed of rigid plastic, metal, flexible rubber, or any other type of material that could be adapted to afford the protection of the PED desired for the application. For example, a metal cover may be used in an application where an elegant style is necessary but watertightness is not. A flexible rubber cover may be selected for an application in a wet environment. A rigid plastic cover may be selected for an application where dropping the PED is a concern. Those skilled in the art may use other types of materials and constructions without deviating from the spirit of the present invention. 
         [0048]    The PED may be mounted in the protective cover using many different mounting techniques. For example, the PED may be mounted using open or closed cell foam inserts in the protective cover. In another embodiment, the PED may be mounted by attaching the PED to the cover with a fastener. In another embodiment, the PED may be mounted by snapping into the protective waterproof cover. In another embodiment, the PED may be held in place by resting in molded features of two halves of a protective case that clamps onto the PED. Those skilled in the art may use other types of locating and holding mechanisms without deviating from the spirit of the present invention. 
         [0049]    The overmolded grommet  106  of the present embodiment is constructed by injection molding a thermoplastic polymerized rubber (TPR) over the front case  102 . The grommet  106  has molded features  116  and  118  adapted to retain the stylus  108 . Features  116  and  118  capture the stylus  108  during transportation, but allow the user to remove the stylus  108  to operate the PED. In other embodiments of the present invention, the stylus  108  may be constrained to the PED with a tether or lanyard, or the constraining features may be incorporated into other components that make up the protective cover. Further, the stylus  108  may not be present in the embodiment, rather, the PED be adapted to be used with the user&#39;s fingernail or with another implement similar to the stylus  108 . 
         [0050]    The membrane  110  of the present embodiment is constructed by thermoforming a sheet of thin plastic. The plastic is selected to be thin enough that the deformation of a stylus conducts the touch to the touch screen, but thick enough to have enough rigidity that the stylus does not catch and rip the membrane. Additionally, the membrane  110  should have enough thickness to endure scratches and other wear and tear without breaking and sacrificing the protective function. Polyvinylchloride material at 0.010 inches to 0.015 inches thickness gives acceptable results. Alternatively, membrane  110  may be constructed by injection molding or other methods. Alternative materials may be used by those skilled in the art to achieve the same results while maintaining within the spirit and intent of the present invention. 
         [0051]    The membrane  110  in the present embodiment may be translucent or at least partially transparent, so that the images displayed on the PED may be visible through the membrane  110 . The membrane  110  may be tinted or colorized in some applications. For example, a protective cover designed as a decorative cover may incorporate a colorized membrane  110 . Further, the membrane may be selectively colorized and the opaqueness may vary. For example, the protective membrane may be printed or painted in the areas not used for the touch screen. A printing process may incorporate a logo, graphics, or labeling for individual buttons for the PED. The printing process may further incorporate features, such as text or graphics, that are used by the software on the PED for a purpose such as simplifying data input or for designating an area on the touch screen for a specific function, such as a help function. The printing or painting processes used on the membrane  110  may be purely decorative and may be for aesthetic purposes only. The printing process may also comprise logos or graphics for the brand identity of the PED cover. Other processes, such as colorizing the raw material for the membrane  110  or adding other components to the raw material, such as metal flakes or other additives, may be used to change the optical features of the membrane  110 . 
         [0052]    The optical performance of the membrane  110  may be changed or enhanced by changing the texture of the area of the touch screen. For example, the membrane may be frosted on the outside to hide scratches or may be imprinted with a lens or other features that change the optical characteristics of the membrane  110 . The membrane  110  may have optical features that are used in conjunction with the software of the PED. For example, all or a portion of the membrane may comprise a lens that magnifies an image to a user. When the user touches the image on the membrane  110  and the touch is transferred to the touch screen, the software in the PED may have to compensate for the positional differences between the image and actual area that was touched by the user. In another example, if a specific portion of the membrane  110  had a specific optical characteristic, the software of the PED may be constructed to display a specific graphic for the area for an intended effect. 
         [0053]    The membrane  110  in the present embodiment has a recessed portion  120  and a raised portion  122 . The recessed portion  120  may be adapted to press flat against the touch screen area of a specific PED. The raised portion  122  may be adapted to fit over an area of the specific PED where several buttons are located. 
         [0054]    The raised portion  122  allows the user to operate the buttons on the PED. The raised portion  122  is adapted such that the buttons on the PED are easily operated through the protective membrane  110 . The raised portion  122  may have special features to aid the user in pressing the buttons. For example, the raised portion  122  may comprise a dimpled area for the user&#39;s finger located directly over the button. Further, a feature to aid the user may comprise a section of membrane  110  defined by a thinner area around the section, enabling the user to more easily deflect the section of membrane over the button. The area of thinner material may comprise a large section or a thin line. Further, tactile elements, such as small ribs or bumps may be incorporated into the membrane  110  in the area of the buttons so that the user has a tactile sensation that the user&#39;s finger is over the button. The tactile element may be particularly effective if the button was a power switch, for example, that turned on the PED. 
         [0055]    The configuration of the membrane  110  may be unique to each style or model of PED, however, the front case  102  and rear case  104  may be used over a variety of PEDs. In the present embodiment, the changeover from one PED variety to another is accomplished by replacing the membrane  110  without having to change any other parts. The present embodiment may therefore be mass-produced with the only customizable area being the membrane  110  to allow different models of PEDs to be used with a certain front case  102  and rear case  104 . 
         [0056]    The hand strap  112  in the present embodiment allows the user to hold the embodiment  100  securely in his hand while using the PED. The hand strap  112  may be constructed of a flexible material, such as rubber or cloth webbing, and may have an adjustment, such as a buckle, hook and loop fastener, or other method of adjustment. In other embodiments, a hand strap may be a rigid plastic handle, a folding handle, or any other method of assisting the user in holding the embodiment. Further, the embodiment may be adapted to be fix-mounted to another object, like a piece of machinery, a wall, or any other object. A fix-mounted embodiment may have other accoutrements adapted for fixed mount applications, such as receptacles for a stylus adapted to a fix-mount, specialized electrical connections, features for locking the PED inside the case to prevent theft, or designs specifically adapted to shed water when rained upon. 
         [0057]      FIG. 2  illustrates a perspective view of the embodiment  100  shown in an open position. The front case  102  and rear case  104  are shown open about the hinge  114 . Membrane  110  is shown installed into gasket  106 , and the recessed portion  120  and raised portion  122  of membrane  110  is illustrated looking from the inside of the case. The clasp mechanisms are not shown in this illustration. Hand strap  112  is shown attached to rear case  104 . 
         [0058]      FIG. 3  illustrates a perspective view of the embodiment  100  shown in an exploded state. The hand strap  116  attaches to the rear cover  104 . The overmolded grommet  106  holds the stylus  108  and is attached to front cover  102 . The membrane  110  attaches to the grommet  106  and is held in place with an o-ring  302 . 
         [0059]      FIG. 4  illustrates a perspective view of the embodiment  100  shown from the rear. The hand strap  116  is shown, along with rear cover  104  and front cover  102 . The stylus  108  is shown inserted into the overmolded grommet  106 . 
         [0060]      FIG. 5  illustrates a top view of the embodiment  100 . The front cover  102 , membrane  110 , stylus  108 , and hinge  114  are all visible. 
         [0061]      FIG. 6  illustrates a section view of the embodiment  100  taken through the section line shown in  FIG. 5 . The front cover  102 , rear cover  104 , overmolded gasket  106 , stylus  108 , membrane  110 , hand strap  112 , and o-ring  302  are all shown hatched in this view. 
         [0062]      FIG. 7  illustrates a detail view of the embodiment  100  shown in  FIG. 6 . Front case  102  and rear case  104  are joined at hinge  114 . Overmolded gasket  106  traps membrane  110  and o-ring  302  locks membrane  110  in place. Overmolded gasket  106  may be formed by molding thermoplastic polymerized rubber over the front cover  102 . 
         [0063]    The replacement of the membrane  110  is accomplished by removing o-ring  302 , pushing the membrane  110  from the overmolded gasket  106 , snapping a new membrane  110  into place, and replacing the o-ring  302 . The ease of replacement of the present embodiment allows a user to quickly replace a damaged membrane  110 , allows a user to upgrade their case to a newer model PED, and may allow a user to select from various membranes  110  for the particular application. One embodiment may have a single case packaged with a small variety of several types of membranes  110 . In such an embodiment, the user may purchase the packaged set, select the membrane  110  that suits the user&#39;s particular PED, and install the selected membrane  110  with ease. 
         [0064]    The protective cover of the present invention may have direct connections through the cover for connecting through the case. Such a connection is known as pass through. The connections may be for power, communication, heat dissipation, optical transmissions, mechanical motion, or other reasons. 
         [0065]    Electrical connections may require an insulated metal conductor from the PED through the wall of the protective cover so that a flexible cable may be attached or so that the PED in its protective case may be placed in a cradle for making the electrical connection. Inside the protective cover, the electrical connections may be made with a flexible cable that is plugged into the PEDs electrical connector before the PED is secured in the protective cover. Alternatively, a fixed connector may be attached to the protective cover and the PED is slid into contact with the fixed connector. Another embodiment may be for a compliant, yet fixed mounted electrical connector to be rigidly mounted inside the protective cover. A compliant, yet fixed mounted electrical connector may comprise spring loaded probes, commonly referred to as pogo pins. Another embodiment may comprise spring fingers that engage the PEDs electrical contacts. On the outside of the protective cover, the electrical contacts may be terminated into a fix-mounted connector adapted to receive a cable from a computer. The connector may be designed to receive a cable that plugs directly into the PED or it may be adapted to receive a different connector. Further, the electrical connection to the PED may be permanently attached to a cable that extends out of the protective cover. Another embodiment may be to have a small trap door that opens in the protective cover to allow access to the electrical connections. While the trap door exposes the PED to the elements the cover is designed to protect against, a direct electrical connection may eliminate a potential cabling connection problem. Connections for fiber optics can be handled in similar fashions as the electrical connections. An embodiment with a power connection may comprise the use of inductive coils located in proximity to each other but on opposite sides of the protective cover. Those skilled in the art of may devise other embodiments for connecting through the protective cover without deviating from the scope and intent of the present invention. 
         [0066]    Through the air communications, such as infrared and over the air radio frequency (RF) communications may pass through the protective cover. The material for the front case  102  and rear case  104  may be selected to be clear plastic, such as polycarbonate. The infrared transceiver of the PED can communicate through a clear plastic case to another infrared transceiver outside of the case. Further, the appropriate selection of material for the protective case can thereby enable various RF transmissions, such as cellular phone communications or other wireless communication protocols. 
         [0067]    An infrared transmission through the protective case of an embodiment of the invention may be accomplished by making the entire protective case out of a clear material. Alternatively, a selected area of the protective case may be clear while the remainder of the case is opaque. The selected area may be constructed of a separate piece that allows the infrared light through the protective case. Alternatively, the selected area may be constructed of a portion of the protective case that was manufactured in a way so as not to be opaque, such as selectively not painting or plating the area of a plastic protective case. Further, the clear material through which the transmission occurs may be tinted in the visual spectrum but be translucent or at least partially transparent in the infrared spectrum of the device. 
         [0068]    A protective case may allow RF transmissions to and from the PED while the case is closed. Such a case may be constructed of a non-metallic material. In some embodiments, the material of the protective case may be tuned to allow certain frequencies to pass through the protective cover and tune out other frequencies, through loading the material used in the protective cover with conductive media or through varying the thickness of the case and other geometries of the case in the area of the PED transmission and reception antenna. 
         [0069]    In a different embodiment, it may be desirable to shield the PED from outside RF interference. In this case, the protective cover may be a metallic construction or may be plastic with a metallized coating. Further, membrane  110  may have a light metallized coating applied so that membrane  110  is slightly or fully conductive. An application for such an embodiment may be the use of the PED in an area of high RF noise that may interfere with the operation of the PED, or conversely, the use may be in an area that is highly susceptible to external RF interference and the PEDs RF noise may be interfering with some other device. 
         [0070]    The PED may be equipped with a camera or other video capture device. A protective cover may have provisions to allow a clear image to be seen by the video capture device through the case. Such provisions may include an optically clear insert assembled into the protective case. Other embodiments may have a sliding trap door whereby the user of the PED may slide the door open for the camera to see. Additionally, other embodiments may comprise a molded case that has an optically clear lens integrally molded. Such an embodiment may be additionally painted, plated, or overmolded, with the lens area masked so that the painting, plating, or overmolding does not interfere with the optics of the lens. 
         [0071]    An optically clear area may be used for a barcode scanner portion of a PED to scan through the case to the outside world. In such an embodiment, a barcode scanner may be protected from the elements while still maintaining full functionality in the outside world. 
         [0072]    The PED may have indicator lights that indicate various items, such as power, battery condition, communication, and other status items. The indicator lights may be in positions on the PED that are not readily viewable through the protective membrane  110 . The indicator lights may be made visible through the protective case by using light pipes that transmit the light from the PEDs status light to the outside of the protective case. Such light pipes may be constructed of clear or tinted plastic, or other translucent or semi-transparent material. The light pipes may be formed as an integral feature to the protective case or may be separate parts that are formed separately and assembled to the protective case. 
         [0073]    The PED may have a speaker or other element that makes noise and/or the PED may have a microphone for receiving audio signals. The speaker may be an audio quality device for reproducing sound or it may be a simple buzzer for indicating various functions of the PED. The microphone may be an audio quality device or it may be a low performance device. Special provisions may be made for transmitting sound through a protective case. Such provisions may range from a single hole in the case to a tuned cavity that would allow sound to pass through with minimum distortion. Other embodiments may include a transmissive membrane adapted to allow sound to pass through the protective case with a minimum of distortion. Such membranes may be located near the speaker and microphone elements of the PED. Such membranes may be watertight membranes known by the brand name Gore-Tex. 
         [0074]    The PED may generate heat during its use and provisions for dissipating the heat may be built into the protective cover. A heat-dissipating device may be integral to the protective cover or may comprise one or more separate parts. For example, a metallic protective cover may be adapted to touch the PED in the area of heat generation and conduct the heat outwardly to the rest of the protective cover. The protective cover may thereby dissipate the heat to the external air without overheating the PED. In another example, a separate heat sink may be applied to the PED and allowed to protrude through a hole in the protective cover. The heat sink may thereby transfer the heat from the PED to the ambient environment without overheating the PED. The heat sinks may be attached to the PED with a thermally conductive adhesive. Other embodiments may include vent holes for heat dissipation and air circulation. 
         [0075]    The PED may have a button that may not be located underneath the membrane  110 . An embodiment may include a flexible, pliable, or otherwise movable mechanism that may transmit mechanical motion from the outside of the case to a button on the PED. Such an embodiment may have a molded dimpled surface that is pliable and allows a user to activate a button on a PED by pressing the dimpled surface. Another embodiment may have a rigid plunger that is mounted on a spring and adapted to transmit the mechanical movement from the exterior of the case to a button on the PED. The buttons on the PED may be located on any side of the PED and an embodiment of a case may have pliable areas adapted to allow the user to press buttons that are not on the front face of the PED. 
         [0076]      FIG. 8  is an illustration of embodiment  800  of the present invention wherein the PED  802  is encapsulated by a protective cover  804 . The installation of the PED  802  is to slide PED  802  into the opening  808 , then fold door  806  closed and secure with flap  810 , which is hinged along line  812 . Areas  814  and  816  may comprise a hook and loop fastener system or other fastening device. Recessed area  818  is adapted to fit against touch screen  820  of PED  802 . 
         [0077]    Embodiment  800  may be comprised of a single molded plastic part that may be very low cost. As shown, embodiment  800  may not be completely weathertight, since the door  806  does not completely seal the enclosure. However, such an embodiment may afford considerable protection to the PED  802  in the areas of dust protection, scratch protection, and being occasionally rained upon. Further, the low cost of the embodiment  800  may be changed often during the life of the PED  802 . 
         [0078]    Embodiment  800  may have custom colors, logos, or designs that allow a user to personalize their PED with a specific cover that is suited to their mood or tastes. The colors, logos, and designs may be integrally molded into the cover  804 . Alternatively, different colors, logos, and designs may be applied in a secondary operation such as printing, painting, plating, or other application process. 
         [0079]      FIG. 9  is an illustration of embodiment  900  of the present invention wherein a decorative cover  902  is snapped over a PED  904 . The ends  906  and  908  snap over the PED ends  910  and  912  as an attachment mechanism for cover  902  to PED  904 . Recessed area  914  is adapted to fit against touch screen  916 . 
         [0080]    Embodiment  900  may be a cover for decorative purposes only, or may be for protective purposes as well. Cover  902  may be emblazoned with logos, designs, or other visual embellishments to personalize the PED  904 . The colors, logos, and designs may be integrally molded into the cover  904 . Alternatively, different colors, logos, and designs may be applied in a secondary operation such as printing, painting, plating, or other application process. 
         [0081]    Embodiment  900  may be attached by snapping the cover  902  onto PED  904 . Special provisions in the case of PED  904  may be provided for a snapping feature of cover  902 , or cover  902  may be adapted to hold onto PED  904  without the use of special features in PED  904 . 
         [0082]    The features used to secure cover  902  to PED  904  may be any mechanism whereby the cover  902  can be secured. This includes snapping, clamping, fastening, sliding, gluing, adhering, or any other method for securing two components together. 
         [0083]      FIG. 10  illustrates a perspective view of an embodiment of a receiver  1002  for holding the protective case  100 . The protective case  100  is held into receiver  1002  in such a manner that the touch screen display is facing into the receiver  1002 , to afford the touch screen display with protection. 
         [0084]      FIG. 11  illustrates a perspective view of the embodiment of a receiver  1002  shown from the opposite side as  FIG. 10 . Receiver  1002  is comprised of a back  1102 , a belt clip mechanism  1104 , and four clip areas  1106 ,  1108 ,  1110 , and  1112 . The protective case  100  is placed into the receiver  1002  by inserting one end into the receiver, then rotating the protective case  100  into position such that the snapping action of clip areas  1106 ,  1108 ,  1110 , and  1112  are engaged to hold protective case  100  securely. 
         [0085]    Receiver  1002  may be adapted to clip onto a person&#39;s belt or may be adapted to be mounted on a wall or other location where the PED may be stored. The orientation of the protective case  100  is such that the touch screen element of the PED is protected during normal transport and storage, since the touch screen interface is facing the back  1102  of the receiver  1002 . 
         [0086]    Receiver  1002  may be made of compliant plastic that allows the clip areas  1106 ,  1108 ,  1110 , and  1112  to move out of the way and spring back during insertion or removal of the protective case  100 . In the present embodiment, receiver  1002  may be constructed of a single part. In alternative embodiments, receiver  1002  may be constructed of multiple parts and of multiple materials, such as a metal back with spring loaded clips. In other embodiments, special features may be included in the protective case  100  where the receiver  1002  may engage a special feature for securing the protective case  100 . 
         [0087]      FIG. 12  illustrates an embodiment  1200  of the present invention of a protective cover for a PED or other device. A rigid front cover  1202  and a rigid rear cover  1204  are held together with a series of latches  1206 ,  1208 ,  1210 , and  1212 . The protective membrane  1214  protects the touchscreen of the enclosed PED. A folding rigid cover  1216  operates as a rigid shield to prevent the membrane  1214  from any damage. The stylus holder  1220  is formed from an overmolded flexible material in which the membrane  1214  is mounted. 
         [0088]    Embodiment  1200  illustrates yet another embodiment of the present invention wherein a rigid protective cover may be used to contain and protect an electronic device, but provide full usable access to a touchscreen. The protective membrane  1214  and case may be watertight in some embodiments. 
         [0089]      FIG. 13A  illustrates an embodiment of a protective enclosure  1300  that encloses and protects a tablet PC  1302 . PEDs that have touch screens, as described above, have an interactive flat-panel control, i.e., the touch screen display. Tablet PCs are portable electronic computing devices that have a high-resolution interactive flat-panel control that accepts smooth stylus strokes such as handwriting. The embodiment of  FIG. 13A  is crush-resistant, impact-resistant, watertight, and simultaneously allows interactive stylus strokes and other sensitive user inputs to be accurately and easily transmitted through a protective screen membrane  1306  to the interactive flat-panel control of tablet PC  1302 . 
         [0090]    A watertight and shock-absorbing foam cushion  1310  may be fixed and sealed to the underside of the lid  1304  around the interactive flat-panel control opening. The protective screen membrane  1306  is fixed and sealed to the shock-absorbing foam cushion  1310 . The shock-absorbing foam cushion  1310  maintains the water tightness of the enclosure. The cushion  1310  also cushions the flat-panel control of the tablet PC  1302  and protects it against breakage if the enclosure and tablet PC are dropped or otherwise subjected to shock. In accordance with the embodiment of  FIG. 13A , the shock-absorbing foam cushion  1310  has a thickness of approximately 0.25 inches and extends approximately 0.060 inches below the underside of the interactive flat-panel control opening of the lid  1304 . One source of suitable watertight shock-absorbing foam is E.A.R. Specialty Composites of 7911 Zionville Rd., Indianapolis, Ind., 46268. Cushion  1310  allows the protective screen membrane to move a distance of up to 0.125 inches during an impact to the enclosure or when pressure is applied to protect membrane  1306  while pushing the tablet PC control buttons  1308  or writing on the interactive flat-panel control with a stylus through the membrane. The shock-absorbing foam cushion  1310  also pushes the protective screen membrane  1306  flatly against the surface of the interactive flat-panel control of the tablet PC  1302  so that sensitive user stylus strokes and other inputs are accurately transmitted. The pressure of the cushion  1310  on the protective screen membrane  1306  which holds the protective screen membrane  1306  flatly against the interactive flat-panel control of the tablet PC  1302  also keeps display images, viewed through the protective screen membrane, clear and distortion-free. In embodiments of the protective enclosure to protect a touch-screen device, the protective membrane may be adjacent to the touch screen but does not exert mechanical pressure on the touch screen so that mechanical inputs such as style strokes are sensed only when intended. In embodiments of the protective enclosure to protect a tablet PC that has an RF stylus or to protect a handheld device that a capacitance-sensing interactive flat-panel control, the protective membrane may be pressed flat against the interactive flat-panel control which allows undistorted viewing but does not adversely affect the control since the interactive control uses capacitance or radio frequencies for interactive input instead of mechanical pressure. 
         [0091]    The protective screen membrane  1306  in the embodiment of  FIG. 13A  is at least partially transparent and has a thickness of approximately 0.010 inches. The thickness of the protective screen membrane  1306  should be typically in the range of 0.001 inches to 0.020 inches so that stylus strokes on the upper surface of protective screen membrane  1306  are transmitted accurately to the interactive flat-panel control of the tablet PC  1302 . Likewise, protective screen membrane  1306  may be flexible or semi-rigid and may be made of polyvinylchloride or other suitable transparent thermoplastic, such as, for example, polyvinylchloride, thermoplastic polycarbonate, thermoplastic polypropylene, thermoplastic acrylonitrile-butadiene-styrene, thermoplastic polyurethane, which has a hardness and texture that permits the stylus to smoothly glide across the surface without skipping, grabbing, or catching against the surface. Some tablet PCs utilize a stylus which transmits strokes to the PC by way of radio frequency transmission. Protective screen membrane  1306  may be made of a rigid, clear, engineered thermoplastic such as, for example, thermoplastic polycarbonate or other thermoplastics as described above, for enclosing a tablet PC. A protective screen membrane  1306  that is rigid may include watertight access ports that allow operation of mechanical buttons or switches of the tablet PC  1302 , such as, for example, control buttons  1308 . The watertight access ports may include holes that have a moveable watertight plug, or any type of watertight button or lever. Protective screen membrane  1306  may include an anti-glare coating or can be made with an anti-glare texture so that display images are clearly viewable without distortion through the protective screen membrane  1306 . 
         [0092]    In the embodiment of  FIG. 13A , the lid  1304  of the protective enclosure  1300  may have an external stylus holder  1324  that securely holds a stylus used with the tablet PC  1302 . 
         [0093]    As described above with respect to  FIG. 1 , the lid  1304  and the base  1312  may have air-permeable watertight vents  1318 ,  1326  that permit the cooling fans of the tablet PC  1302  to force air exchange to dissipate heat by convection so that the tablet PC  1302  does not overheat. Watertight vents  1318 ,  1326  may comprise holes in the lid  1304  and base  1312  that are made watertight by covering and sealing the holes with an air-permeable watertight membrane such as, for example, a fabricated expanded polytetrafluoroethylene (ePTFE) membrane. One source of expanded polytetrafluoroethylene (ePTFE) membranes is W.L. Gore &amp; Associates, Inc. of 555 Papermill Road, Newark, Del.,  19711 . 
         [0094]    The embodiment of  FIG. 13A  may also comprise a pod door  1322  that allows access to table PC interfaces such as, for example, PCMCIA or Smart Card slots. The pod door  1322  is attached to the lid  1304  so that it may be removed or opened. In the embodiment of  FIG. 13A , the pod door  1322  is hingedly connected to a portion of the base  1312  at a location of the base  1312  that has an opening that allows access to the tablet PC interfaces. The opening can be covered by a watertight seal  1320 , such as, for example, an O-ring that is part of pod door  1322 . 
         [0095]    The underside of the lid  1304  also has a watertight seal, such as an O-ring, so that when compound latches  1328 ,  1330 ,  1332 , and  1334  are closed, the O-ring or seal of the lid  1304  forms a watertight seal against the base  1312 . The protective enclosure  1300  protects the tablet PC  1302  from water and dust intrusion sufficient to comply with Ingress Protection (IP) rating of IP  67 , i.e., the protective enclosure totally protects the enclosed tablet PC from dust and protects the enclosed tablet PC from the effects of immersion in one meter of water for 30 minutes. 
         [0096]    The protective enclosure of the embodiment of  FIG. 13A  may further comprise protective overmolding  1316  attached to the lid  1304 . A similar overmolding may be attached to the base  1312 . The protective overmolding  1316  may be made of material that is easily gripped in slippery conditions and provides additional shock absorption such as, for example, rubber or silicone. The protective overmolding  1316  extends above the surface of the lid in pre-determined areas to provide protrusions that are easily gripped even in slippery conditions. The protective enclosure of the embodiment of  FIG. 13  may further comprise watertight plugs such as access port plug  1314  that fit snugly into openings in the base  1312  that provide access to various interfaces, connectors, and slots of the tablet PC  1302 . 
         [0097]      FIG. 13B  illustrates a shell lid  1304  of the embodiment of  FIG. 13A . Shell lid  1304  and base  1312  may be made of impact/crush resistant material such as glass-fiber reinforced engineered thermoplastic, such as for example, glass reinforced polycarbonate. Alternatively, the shell lid  1304  and shell base may be made of thermoplastic polycarbonate, thermoplastic polypropylene, thermoplastic acrylonitrile-butadiene-styrene, and thermoplastic compositions containing one or more thereof, or other engineered thermoplastics that provide a shock-resistant and impact resistant shell may be used. The engineered thermoplastics may be reinforced with glass fibers, carbon fibers, metal fibers, polyamide fibers, and mixtures thereof. Shell lid  1304  may be further reinforced with stiffeners  1334 ,  1336 ,  1338 ,  1340  that are integrally embedded into the shell lid around the perimeter of an opening in the shell that is directly over the interactive flat-panel control portion of the tablet PC. The stiffeners may be made of steel or other hard material so that the stiffeners provide additional strength and prevent flexing of the lid  1304  which enhances the watertightness and the impact/crush resistance. 
         [0098]      FIG. 14  is an illustration of the embodiment of  FIG. 13A  with the lid  1404  detached from the base  1412 . To protect the tablet PC  1402  using the protective enclosure  1400 , the tablet PC  1402  is disposed to fit snugly into the base  1412 . The lid is oriented so that hooks  1436 ,  1438  area aligned with pin  1440  that is connected to a portion of the base  1412  and the lid is closed so that hooks  1436 ,  1438  are retained by pin  1440 . Compound latches  1428 ,  1430 ,  1432 , and  1434  are then snapped onto the lid so that the lid is compressed tightly against the base providing a watertight seal. 
         [0099]      FIG. 15  is a bottom view of the embodiment of  FIG. 13 . The base  1516  of protective enclosure  1500  includes watertight vents such as watertight vent  1506  for air exchange to permit heat and sound dissipation from the enclosed tablet PC while at the same time maintaining watertightness. 
         [0100]    Pod release knobs  1512 ,  1518  are attached to the base  1516  so that the knobs can be rotated clockwise to securely wedge against an edge of pod door  1522  to close the pod door  1522  tightly against a rim around the pod opening in base  1516  to create a watertight seal. Knobs  1512 ,  1518  can be rotated counter-clockwise to release pod door  1522  to access the interfaces of the tablet PC covered by pod door  1522 . 
         [0101]    To provide additional protection against mechanical shock, heavy-duty corner bumpers such as bumper  1504  may be securely attached to the corners of base  1516 . 
         [0102]    As shown in  FIG. 15 , an adjustable heavy-duty handle may be attached to the base  1516  of the protective enclosure  1500  to allow easy and reliable transportation of the protective enclosure  1500  that encloses a tablet PC. In some circumstances, it is convenient to hold the protective enclosure using hand strap  1514  that is made of strong slightly stretchable fabric. Hand strap  1514  attaches to four points of the base  1516  to that a user&#39;s hand or wrist can be inserted along the either the longer or shorted length on the protective enclosure  1500  and enclosure tablet PC. Hand strap  1514  may be made of neoprene or other strong stretchable material to securely hold the protective enclosure to the user&#39;s arm even in slippery conditions. The protective enclosure may further include a neck strap to provide a comfortable solution for using the tablet PC while standing. 
         [0103]      FIG. 16  illustrates a top view of the protective enclosure base  1600 . Watertight vents such as watertight vent  1616  allow air exchange for heat dissipation and sound transmission from an enclosed tablet PC. Seal rim  1614  is an integrally formed part of the protective enclosure  1600  which is compressed against an O-ring in the protective enclosure lid to provide a watertight seal when compound latches  1628 ,  1630 ,  1632 , and  1634  are closed onto the lid. 
         [0104]    Internal bumpers  1602 ,  1604 ,  1608 ,  1610  attach to the interior corners of protective enclosure base  1600  to provide cushion and mechanical shock protection to an enclosed tablet PC. The L-shape and non-solid interior of internal bumpers  1602 ,  1604 ,  1608 ,  1610  allows the bumpers to deflect and absorb the shock if the enclosed tablet PC is dropped or otherwise subjected to mechanical shock. The protective enclosure provides shock absorption sufficient to meet MIL-STD 810F, Method 516.5, Procedure 4 which is a Transit Drop Test. In the Transit Drop Test, the protective enclosure encloses a tablet PC or a mass equivalent to a tablet PC. The protective enclosure is sequentially dropped onto each face, edge, and corner for a total of 26 drops over plywood from a height of 48 inches. The protective enclosure is visually inspected after each drop and a functional check for leakage is performed after all drops are completed. 
         [0105]    Some tablet PCs have a docking connector disposed on the underside of the tablet PC so that the tablet PC can connect to power and signals. For example, emergency vehicles such as ambulances, fire trucks, or patrol cars, may have a docking station installed near the driver&#39;s seat onto which the driver may dock a tablet PC. The embodiment of protective enclosure base  1600 , as illustrated in  FIG. 1 , may comprise a docking connector channel  1624  that is recessed with respect to the upper surface of the base that allows a docking connector to run from a docking connector that is disposed in the center underside of the tablet PC to access port  1626 . Alternatively, a docking pass-through connector  1620  may be made an integral and watertight part of the protective enclosure base  1600  so that the tablet PC docking connector attaches to the docking pass-through connector  1620  which, in turn, connects to the docking station in substantially the same manner as an unenclosed tablet PC. 
         [0106]      FIG. 17  illustrates another embodiment of protective enclosure  1700  for a handheld electronic device  1702  that has an interactive flat-panel control such as, but limited to, a capacitance-sensing interactive flat panel control, a touch screen or other interactive control. Handheld electronic devices that have an interactive flat-panel control benefit from being enclosed in a rugged protective enclosure that is crush-resistant, watertight, and shock-resistant and that simultaneously allows the user to interact with a sensitive interactive flat-panel control. Handheld electronic devices that have interactive flat-panel control may include music players, MP3 players, audio player/recorders, video players, computers, personal digital assistants (PDAs), GPS receivers, cell phones, satellite phones, pagers, monitors, etc. For example, Apple Computer Ipod is a popular handheld interactive device that plays MP3 or otherwise digitally-encoded music/audio. The Apple Ipod has an interactive flat-panel control in which a portion of the front panel is a flat-panel display and portion of the front panel is an interactive flat-panel control, called a touch wheel in some versions of the Ipod and click wheel in other versions of the Ipod, that has capacitive touch/proximity sensors. One function of such an interactive flat-panel control, i.e. touch wheel, is that the control can emulate a rotary control knob by sensing circular motion of a user&#39;s finger using capacitive sensors. The click wheel has the same function with the additional feature of sensing proximity of a user&#39;s finger and emulating button presses by a user&#39;s finger at pre-determined areas. 
         [0107]    In the embodiment of  FIG. 17 , the shell lid  1706  and the shell base  1704  are made of polycarbonate or other engineered thermoplastics such as polyethylene, polypropylene, etc. that are crush-resistant and impact resistant. Shell base  1704  has a watertight seal  1718 , which may be an overmolded gasket, o-ring, liner or other seal that prevents water from entering the protective enclosure  1700  when the handheld interactive device  1702  is enclosed inside the protective enclosure  1700 . Shell base  1704  and shell lid  1706  may include watertight vents, electrical connectors, see-through areas or features as disclosed with respect to  FIG. 1 . 
         [0108]    In the embodiment of  FIG. 17 , shell lid  1706  includes apertures over predetermined portions of the handheld interactive device  1702 , such as the areas directly over the display screen  1714  and the interactive flat-panel control  1712 , or other designated areas, as desired. A protective screen membrane  1710 , that is at least partially transparent, is permanently or removably fixed in a watertight manner to the underside of shell lid  1706  in the aperture that is over the display screen  1714 . The protective screen membrane  1710  may be recessed with respect to the upper surface of the shell lid  1706  which provides protective elevated rim that protects the display screen  1714  from breakage. Protective screen membrane  1710  may be PVC, silicone, polyethylene or other material that is watertight and rugged. In the case that display screen  1714  is a touch screen, the protective screen membrane  1710  should be smooth enough and thin enough that stylus strokes and other inputs are transmitted accurately to the touch screen as disclosed above with respect to  FIG. 1 ,  FIG. 12 , and  FIG. 13 . Alternatively, it may be desirable not to have an aperture in shell lid  1706  for a protective membrane  1710 . In another embodiment, the shell lid  1706  can be made of a transparent material so that a transparent window can be formed in the shell lid  1706  in place of the protective screen membrane  1710 . The transparent window is aligned with the display screen  1714  so that the user can view the display screen  1714 . In this case, a protective elevated rim that is aligned with the display screen  1714  is not required in the shell lid  1706  to protect the display screen  1714  from damage since there is no protective screen membrane  1710 . If the display screen  1714  is a touch screen, the material of the shell lid  1706  that is aligned with the display screen  1714  to provide a window can be made thinner to allow the touch screen to properly operate. 
         [0109]    As also shown with respect to the embodiment of  FIG. 17 , a protective control membrane  1708  is permanently or removably fixed in a watertight manner to the underside of shell lid  1706  in an aperture that is aligned with the interactive flat-panel control  1714  of the handheld device  1702 . The protective screen membrane  1710  is recessed with respect to the upper surface of the shell lid  1706  which provides protective elevated rim that protects the display screen  1714  from breakage and provides tactile feedback that guides a user&#39;s finger to the desired area, even in slippery conditions. Of course, the protective elevated rim may simply comprise the portion of the shell lid  1706  that is formed as a result of making an aperture in the shell lid  1706  and overmolding a protective touch-control membrane  1708  on an inside surface of the shell lid  1706 . In other words, the thickness of the shell lid  1706  creates a protective rim since the protective touch-control membrane  1708  is overmolded or otherwise attached to the back side of the shell lid  1706 . In that case, the rim is not elevated with respect to the surface of the shell lid  1706 , but rather, is elevated with respect to the membrane to form a protective rim. 
         [0110]    Interactive flat-panel control  1712  has capacitive sensors, which are part of a proximity/touch detector circuit. When a grounded object, such as a person&#39;s finger, which has free air capacitance of several hundred picofarads, is brought close to the capacitive sensors, the total capacitance measured by the detector circuit increases because the capacitance of the object with free air capacitance adds to the capacitance of the sensors since the total capacitance of two capacitors in parallel is additive. Multiple sensors may also be arranged so that movement of an object with free air capacitance can be detected, for example, movement of a person&#39;s finger in a circular motion analogous to turning a mechanical control knob. Some examples of interactive flat-panel controlled PEDs include Ipod and Ipod Mini music and audio players from Apple Computer. In some PEDs, such as the Apple Ipod, capacitive sensors may be disposed below a front panel made from a dielectric such as polycarbonate, which has a dielectric constant in the range of 2.2-3.8. In the embodiment of  FIG. 17 , the protective control membrane  1708  is made of thin polycarbonate that is slightly flexible or other engineered thermoplastics that provide the rugged watertight protection and at the same time permit the capacitive sensors of the interactive flat-panel control  1712  to function correctly. Likewise, a protective control membrane  1708  with a dielectric constant that is too high may retain an electric charge long enough to reduce the response rate of the sensor to motion of a user&#39;s finger from one capacitive sensor zone of the interactive flat-panel control  1712  to another. A protective control membrane  1708  that is conductive or has a dielectric constant that is too low may diminish the sensitivity of the capacitive sensor by combining in series the capacitance of the protective membrane and the dielectric front panel of the PED which results in a lowering of the overall capacitance. 
         [0111]    Total capacitance between an object, such as a finger touching the protective control membrane  1708 , and interactive flat-panel control  1712  is a function of the thickness and the dielectric constant of the protective control membrane  1708 . The capacitance between the object, such as a finger, and the capacitive sensors of the interactive flat-panel control  1712  is proportional to the distance between the object and the sensors. The sensitivity of the capacitive sensors to the object may be diminished or completely eliminated if the protective control membrane  1708  is too thick. In the embodiment of  FIG. 17 , the thickness of the protective control membrane is approximately 0.020 inches. The protective control membrane  1708  may be any thickness in the range of 0.003 inches to 0.020 inches that is adequate to provide a rugged watertight membrane through which capacitance can be correctly sensed by the interactive flat-panel control  1712 . 
         [0112]    The upper surface of the protective control membrane  1708  has a velvet/matte texture with a texture depth of 0.0004 to 0.003 inches that reduces the surface area of the membrane that is in frictional contact with the user&#39;s finger and permits a user&#39;s finger to glide rapidly upon the surface of the membrane without catching or sticking as a result of the reduced friction. The hardness of the polycarbonate material, or other hard engineered thermoplastic, also reduces the friction. 
         [0113]    Headphones or other accessories may be electrically connected to handheld device  1702  the through the protective enclosure  1700  by disposing the wire of the headphone or accessory in an insertable gasket  1716  which fits snugly into one end of the shell base  1704 . 
         [0114]      FIG. 18  illustrates another embodiment of protective enclosure  1800  which is substantially the same as protective enclosure  1700  of  FIG. 17 . However, protective enclosure  1800  has an alternative electrical pass-through for accessories. In the embodiment of  FIG. 18 , shell base  1804  includes an adapter cable  1816  that has an adapter plug  1812  at one end which plugs into a jack of handheld device  1802 . At the other end of the adapter cable  1816  is an adapter jack  1814  that is molded into, or otherwise integrally made part of, shell base  1804 . An external accessory, such as a pair of headphones, may then be plugged into the adapter jack  1814  while the handheld device  1802  in enclosed in protective enclosure  1800 . Alternatively, a one-piece adapter that includes both a jack  1814  and a plug  1812  without a cable  1816  may be integrally disposed into shell base  1804 . 
         [0115]    Shell lid  1806  is adapted to retain an O-ring  1808  that seals the protective enclosure  1800  when shell lid  1806  is latched tightly onto shell base  1804  so that water cannot enter protective enclosure  1800 . 
         [0116]      FIG. 19  illustrates in the open position a crush-resistant, impact-resistant, watertight, protective enclosure  2000  for an electronic device such as a laptop computer. The protective enclosure  2000  may be manufactured in a manner similar to the enclosure of  FIG. 13  comprising an impact/crush resistant material such as glass-fiber reinforced engineered thermoplastic, such as for example, glass reinforced polycarbonate. It may also be made of thermoplastic polycarbonate, thermoplastic polypropylene, thermoplastic acrylonitrile-butadiene-styrene, and thermoplastic compositions containing one or more thereof, or other engineered thermoplastics that provide a shock-resistant and impact resistant shell. 
         [0117]    The inside of the enclosure is covered with a hook and loop liner  2002 . Shock absorbing corner bumpers  2004  have hook and loop type bases so that they may attach at any point on the liner inside the enclosure at the corners of the electronic device to secure electronic devices of various sizes and provides a shock absorbent suspension system for the devices. The shape of the bumpers may vary in size and in depth. They may also vary such that the laptop is raised a predetermined height for the bottom of the enclosure so that there may be access to the ports and external drives such as CD and DVD. These bumpers allow the enclosure to be adaptable to any size laptop computer by placing it inside the enclosure and securing it into position with the bumpers  2004 . Straps  2006  also secures the laptop into position.  FIG. 20  illustrates a laptop  2008  secured in position as described above. An opening for a door or docking position  2010  may be provided that allows the case to be prewired for power or other USB connections. The watertight access ports may include holes that have a moveable watertight plug, or any type of watertight button or lever. 
         [0118]    The liner  2002  may also have some cushioning that cushions the laptop and protects it against breakage if the enclosure and laptop are dropped or otherwise subjected to shock. Normally, however, most of the cushioning is provided by the corner bumpers and the liner is not cushioned. In accordance with the embodiment of  FIG. 19 , the liner  2002  has a thickness of approximately 0.25. 
         [0119]    This enclosure is also adaptable to protect PC tablets of the type illustrated in  FIG. 13A . The hook and loop liner may be adjacent to the touch screen but does not exert mechanical pressure on the touch screen so that mechanical inputs such as style stokes are sensed only when intended. The engineered thermoplastics may be reinforced with glass fibers, carbon fibers, metal fibers, polyamide fibers, and mixtures thereof. Referring to  FIG. 21  the enclosure  2000  may have an elevated protective rim  2012  substantially surrounding a perimeter of the enclosure. This rim may be further reinforced with stiffeners made of steel or other hard material that are integrally embedded into the enclosure so that the stiffeners provide additional strength and protection to the enclosed devices, as shown in  FIG. 13B . An adjustable heavy-duty handle  2016  may be attached to or integrally designed into protective enclosure  2000  to allow easy and reliable transportation. 
         [0120]      FIG. 22  illustrates the top of the enclosure wherein heavy-duty corner bumpers, such as bumper  2016 , provide additional protection against mechanical shock and are securely attached to the corners of the base. The ribs  2012  also substantially surround a perimeter of the base of the enclosure. 
         [0121]      FIG. 23  illustrates a front view of the protective enclosure  2000 . An addition protective rib  2018  is provided along the front of the case and extends around the case on the ends, as shown in  FIG. 24 . 
         [0122]      FIG. 25  illustrates the back of the protective enclosure wherein an opening  2010  is provided in the protective enclosure  2000  which is sealed with a rubber plug  2020 . The plug  2020  of the USB hub is shown in more detail in  FIG. 26 . The USB cable hub allows the protective enclosure  2000  to be wired for both power as well as USB connections. In addition, provisions may be made to provide ventilation for the enclosure through opening  2010 . 
         [0123]      FIG. 26  illustrates the USB hub  2021 . The hub has mounting apertures such as  2022  that are disposed to receive fasteners to mount the hub inside of the protective enclosure  2000 . A USB connecter  2024 , that is disposed to connect to a USB slot in a computer laptop or PC tablet computer, is connected by a cable  2026  to the hub  2020 . 
         [0124]      FIG. 27  illustrates the integrated USB hub  2021  mounted in the enclosure  2000 . The cable  2026  and USB connector  2024  allow a laptop computer or other computer to be connected to the USB hub  2021 . The corner bumpers  2004  are disposed to be removably attached to the enclosure lining  2002  so that the computer may be moved to a new location or the inside of the protective enclosure  2000  to facilitate the making of a connection between a laptop computer and the hub  2020 . The hook and loop liner  2005 , that is attached to the base of the shock absorbing corner bumpers  2004 , extends beyond the base dimensions by a predetermined amount to increase the adhesion between the bumpers  2004  and liner  2002  of the enclosure  2000 . 
         [0125]      FIG. 28  illustrates how the USB assembly comprising the hub  2021 , cable  2026 , and connector  2026  may be mounted in an enclosure for a PC tablet protective enclosure such as  1400  shown in  FIG. 14 . 
         [0126]    The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and other modifications and variations may be possible in light of the above teachings. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. It is intended that the appended claims be construed to include other alternative embodiments of the invention except insofar as limited by the prior art.