Abstract:
A cover window attachment system for an electronic device includes a cover window on a top side of the electronic device; a frame attached to the cover window, the frame further comprising at least one boss configured to protrude into the electronic device; a fastener receiving feature on a distal end of each boss; and a fastener engaging the fastener receiving feature on each boss, the fastener contacting a bottom side of the electronic device, opposite the top side. Also claimed are a method of assembling a cover window to an electronic device and an electronic device including a cover window assembly.

Description:
FIELD OF THE INVENTION 
     The present invention relates to portable electronic devices, and more particularly to a method and apparatus for assembling a cover window to a portable electronic device. 
     BACKGROUND OF THE INVENTION 
     The cover window of a portable electronic device, such as a pen-based “tablet” portable computer, is subject to damage. For example, extensive use may scratch the window, or the window may be cracked or broken during the rigors of portable use. Repair of a worn or damaged cover window is often expensive, and often requires a user of the device to return it to its manufacturer, leaving the user without the use of the device for an extended period. 
     There is a need for a way to repair or upgrade the cover window of a portable electronic device with minimal inconvenience and cost to the user. 
     SUMMARY OF THE INVENTION 
     A cover window attachment system for an electronic device comprises a cover window on a top side of the electronic device; a frame attached to the cover window, the frame further comprising at least one boss configured to protrude into the electronic device; a fastener receiving feature on a distal end of each boss; and a fastener engaging the fastener receiving feature on each boss, the fastener contacting a bottom side of the electronic device, opposite the top side. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a tablet portable computer in accordance with an example embodiment of the invention. 
         FIG. 2  shows an exploded view of the tablet computer of  FIG. 1 . 
         FIG. 3A  shows an exploded section view of a portion of the tablet computer of  FIG. 1 . 
         FIG. 3B  shows a section view of the tablet computer of  FIG. 1  in its assembled state. 
         FIG. 4  shows the tablet computer of  FIG. 1  with a cover window assembly in accordance with an example embodiment of the invention. 
         FIG. 5A  shows an exploded section view of a portion of a tablet computer in accordance with a second example embodiment of the invention. 
         FIG. 5B  shows a section view of the tablet computer of  FIG. 5A  in its assembled state. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a tablet portable computer  100  in accordance with an example embodiment of the invention. A tablet computer uses a pen-based user interface, and performs substantially all of the functions that are performed by a traditional portable computer that uses a keyboard. Computer  100  has a cover window  101  on its top side. Cover window  101  is preferably made of glass, but may also be made of any substantially rigid, substantially transparent material now known or later developed. A user of tablet computer  100  uses pen  102  to “write” on the cover window  101  of computer  100 . Computer  100  senses the location and movement of pen  102 , and provides appropriate feedback on a display behind cover window  101 . The display (not visible in  FIG. 1 ) may be a liquid crystal display, or another kind of display. For example, if computer  100  is executing a drawing program, the display may show a line that appears to be drawn by pen  102  as the user moves pen  102  over cover window  101 . Computer  100  may sense the location of pen  102  using radio-frequency signals, or by other methods. Such methods are known in the art. 
     Cover window  101  is subject to damage. For example, during use, pen  102  repeatedly contacts cover window  101 , and can cause wear. And because computer  100  is lightweight and portable, it may be subjected to other external effects. For example, computer  100  may be repeatedly slid in and out of a carrying case, scratching window  101  in the process. Or computer  100  may be dropped or have another object dropped on it, chipping or breaking window  101 . 
     In prior tablet computers, repair or replacement of the cover window is expensive and difficult. In a computer in accordance with an example embodiment of the invention, repair or replacement of the cover window  101  is simplified, and may even be performed by the computer user. 
       FIG. 2  shows an exploded perspective view of the tablet computer of  FIG. 1 .  FIG. 3A  shows an exploded section view of part of computer  100 , and  FIG. 3B  shows section view of part of computer  100  in its assembled state. Referring to all three  FIGS. 2 ,  3 A, and  3 B, cover window  101  attaches to frame  201 . Frame  201  may be made, for example, of die-cast magnesium, injection-molded plastic, or by other materials and methods. Frame  201  comprises bosses  202 – 205  which may be integrally formed with the main portion  210  of frame  201 , or attached to it. Cover window  101  and frame  201  make up a cover window assembly  206 . The attachment between cover window  101  and frame  201  may preferably be made using an adhesive, or an adhesive tape. Suitable adhesives and tape are known in the art. 
     Cover window assembly  206  is assembled into computer  100  by inserting bosses  202 – 205  into openings in case  207  of computer  100 . Upon assembly, frame  201  partially surrounds display  208 , and cover window  101  is in close proximity to display  208 . A gasket  209  may be situated between frame  201  and case  207  in order to prevent dust, liquids, or other materials from entering computer  100 , and especially to keep dust from finding its way between cover window  101  and display  208 . 
     In example computer  100 , each of bosses  202 – 205  comprises a threaded opening in its distal end. The distal end of each boss  202 – 205  is the end furthest from the main portion of frame  201 . For example, boss  205  comprises threaded hole  301 . Each of the threaded openings receives a screw from the bottom side of computer  100 . For example, hole  301  receives screw  302 . When computer  100  is fully assembled, the head of screw  302  resides in boss  303  comprised in the lower shell  304  of computer  100 , and contacts a bottom side  305  of computer  100 . The other screws reside in similar bosses. 
       FIG. 4  shows computer  100  with cover window assembly  206  in position to be assembled to the rest of computer  100 . The attachment is simple and can be performed with simple tools. A user of computer  100  may replace the cover window assembly inexpensively, and quickly enough that the user would experience little computer downtime. For example, should cover window  101  became scratched, cracked, or broken, a user may order a replacement and do the repair without sending the computer to a repair center. 
       FIG. 5A  shows an exploded section view of part of a computer  500  in accordance with a second example embodiment of the invention, and  FIG. 5B  shows section view of part of computer  500  in its assembled state. In this second example embodiment, cover window  501  and frame  502  make up cover window assembly  503 . Frame  502  comprises a boss  504 , which further comprises a threaded stud  505  protruding from it. During assembly, stud  505  protrudes through lower shell  507  of computer  500 . Stud  505  receives a nut  506 , which secures cover window assembly  503  to the rest of computer  500 . After assembly, nut  506  resides in boss  508  comprised in lower shell  507  of computer  500 , and contacts a bottom side  509  of computer  100 . 
     One of skill in the art will recognize that other kinds of fasteners may be used to assemble a cover window assembly to a tablet computer or other electronic device in accordance with the invention. 
     An additional advantage of a cover window attachment system in accordance with the invention is that it also provides an upgrade path for computer  100 . For example, a less expensive model of computer  100  may comprise a lower-performance window  101  as compared with a more expensive computer model. After owning the computer for a time, a computer user could upgrade to a high-strength glass, or a window with other desirable properties, such as anti-reflective coatings. For example, a less expensive model of computer  100  may have a window made of a plastic, such as polycarbonate, and a user may wish to upgrade to a window made of glass. 
     In a method in accordance with an example embodiment of the invention for assembling a cover window to an electronic device, a cover window assembly as previously described is provided. Each boss on the assembly is inserted into the electronic device from its front side. A fastener is provided to engage with a fastener receiving feature on each boss. Each fastener contacts the back side of the electronic device. When a worn or damaged cover window is to be replaced, the method further comprises removing a second, prior cover window assembly before assembling the new cover window to the electronic device. 
     While the example embodiments described thus far have used a portable computer as the example electronic device, other devices may be used as well. For example, the invention may be embodied in a system comprising a personal digital assistant (PDA). A PDA is a portable device, often handheld and carried with its user, that stores information for ready retrieval and use. For example, a user may store addresses and telephone numbers of people that are frequently contacted, digital books for convenient reading at any location, digital photographs, digital music that can be played when desired, or other kinds of information. A user of a PDA may enter data into or control the PDA using a stylus, “writing” or making selections by touching the stylus to a cover window on the PDA. A PDA may comprise a cover window that is subject to wear or other damage, and a PDA may benefit from a design in accordance with the invention.