Abstract:
A portable electronic device comprises, in one embodiment, one or more risers that protect an upper surface of the housing from being scratched. Additionally, the risers serve as bumpers to reduce damage to the device if it is dropped or bumped. Another embodiment of the present invention incorporates support members made from metal or metal alloy parts that are selectively attached to the laptop housing. These metal support members provide structural support for the housing and therefore aid in preventing the housing from twisting and bending. To further strengthen the housing, a metal frame is used in the upper and/or lower surface of the housing. The frame also serves to protect the enclosed electronics from electromagnetic interference.

Description:
FIELD OF THE INVENTION 
     This invention relates to computing devices and more particularly to an apparatus and method of strengthening and protecting the housing for a portable electronic device. 
     BACKGROUND OF THE INVENTION 
     The first personal computers were introduced to the work place, in substantial numbers, in the early 1980&#39;s. Since then, the popularity of computers in the workplace has grown tremendously. Today, computers are commonplace in most work environments and are essential to many daily business transactions. 
     The first computers introduced to the workplace were stationary and primarily designed to sit on a platform, such as a desk or table. However, as new low-power electronic circuitry such as complementary metal oxide semiconductor (CMOS) was developed alongside new longer lasting batteries (nickel hydride), portable computers began to emerge. Portable computers were attractive to many industries because employees were less confined to their offices. Work could be completed at home or on business trips away from the office. 
     Portable computers can be classified as being either (a) handheld (palmtop), (b) luggable or (c) laptop (notebook) computers. Palmtop computers are generally characterized by their size and computing capability, which is typically less than a desktop or laptop computer. An example of a palmtop computer is an HP 300LX. Luggable computers are, in essence, desktop computers that are portable. These computers are generally constructed with a handle or handgrip by which the luggable computer may be carried. An example of a luggable computer is an Apple iMac™. Notebook computers are generally characterized by their size and weight as well but their computing capability may equal or exceed that of a luggable or desktop computer. An example of a laptop computer is a Hewlett-Packard OmniBook 900™. 
     Modern laptop computers are much thinner than their predecessors. The outer surface or housing is typically composed of molded plastic. A display unit (an upper portion of the housing) is attached to a base unit (lower portion of the housing). The lower portion of the housing contains most of the electronic circuitry (henceforth referred to as electronics) and is attached to the upper portion of the housing with a hinge. The housing surrounding the display is typically constructed of molded plastic and consequently is susceptible to bending and twisting which could damage the enclosed electronics. Additionally, if the computer is dropped, the housing does not provide enough protection to prevent damage to the internal electronics. Some computer manufacturers have addressed this problem by constructing selected portions of the housing, specifically the upper portion that supports the screen, of metal. A preferred metal used to construct the upper portion of the laptop housing is magnesium. 
     Magnesium is a metal that is silvery white in color and is extremely light in weight. Magnesium is approximately two-thirds the density of aluminum and can be combined with other metals to create alloys that are extremely strong. In this regard, magnesium is well suited as a structural material for use in laptop computers. Additionally, magnesium is not very reactive; for example, magnesium reacts only slightly with most organic chemicals including hydrocarbons, aldehydes, alcohols and most oils. Thus, as an outer surface material (housing) for a laptop computer, magnesium is essentially stain resistant. 
     Manufacturers of conventional laptop computers employing magnesium as a structural material, however, are met with new challenges: (1) molded or die cast magnesium parts, which are commonly used to form the upper surface of the laptop housing, are still lacking in providing adequate support to prevent the upper housing from substantially bending and twisting; (2) magnesium is typically painted when used as a surface material. The painted surface is easily scratched and consequently causes the laptop to appear older thus creating an appearance of being inferior in quality; and (3) magnesium, as a housing material for a laptop computer, is significantly more expensive than molded plastic. Unless one or more of these challenges are addressed, many prospective users of portable electronic devices will conclude that the problems associated with using these devices outweigh their benefits. 
     SUMMARY OF THE INVENTION 
     A portable electronic device comprises, in one embodiment, one or more risers that protect an upper surface of the housing from being scratched. The risers serve as bumpers to reduce damage to the device if it is dropped or bumped. Another embodiment of the present invention incorporates support members made from metal or metal alloy parts that are selectively attached to the laptop housing. These metal support members provide structural support for the housing and therefore aid in preventing the housing from twisting and bending. To further strengthen the housing, a metal frame is used in the upper and/or lower surface of the housing. The frame also serves to protect the enclosed electronics from electromagnetic interference. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1 A-B is a perspective view of a preferred embodiment of the present invention wherein a portable electronic device has a riser on the upper surface. 
     FIGS. 2A-B shows a portable electronic device in an alternative embodiment where a grip serves as a riser. 
     FIG. 2C shows a side view of a portable electronic device housing in an alternative embodiment wherein a hinge assembly serves as a riser. 
     FIGS. 3A-B shows magnesium parts being used to strengthen a portable computer housing in an alternative embodiment of the invention. 
     FIGS. 4A-C shows an embodiment of the invention wherein a frame is made from a metal or metal alloy and is used to strengthen the display unit. 
     FIGS. 5A-B shows a structural support member to which the portable electronic device housing is attached. 
     FIGS. 6A-B shows a portion of the portable electronic device housing wherein the riser is removed thereby revealing apertures formed in the upper surface. 
    
    
     DETAILED DESCRIPTION 
     In a preferred embodiment of the present invention, a housing for a portable electronic device is described. The housing addresses many of the aforementioned challenges associated with manufacturing laptop computers including providing structural support necessary to prevent bending and twisting of the laptop housing, protecting the upper surface of the housing from being scratched and lowering manufacturing costs associated with providing a substantially metal (magnesium) housing. 
     FIG.  1 ( a ) shows a perspective view of a preferred embodiment of the present invention comprising a housing  102  (outer shell) for a portable electronic device  100 . While a portable computer is shown in FIG.  1 ( a ) as portable electronic device  100 , those skilled in the art will appreciate that portable electronic device  100  could also be a portable CD player, game device, global positioning system (GPS) receiver, cellular phone or other portable electronic devices and still fall within the spirit and scope of the present invention. The housing  102 , as shown in FIG.  1 ( a ), further comprises an upper surface  104 , lateral surfaces  106 , a lower surface  108 , a hinge  110  and a riser  112 . In a preferred embodiment of the present invention, the upper surface  104  of the housing  102  is formed of magnesium, although other metals and metal alloys may be used, such as aluminum, titanium, and magnesium-aluminum-zinc. The lower surface  108  and lateral surface  106  of the housing  102  are preferably formed from molded plastic. Although FIG.  1 ( a ) shows a preferred embodiment of the present invention where a base unit and a display unit are hinged together, those skilled in the art will appreciate that the aforementioned embodiment may comprise an unhinged single unit. FIG.  1 ( b ) shows a cross-section of FIG.  1 ( a ) where the riser  112  protrudes above the upper surface  104 . In a preferred embodiment, the height of the riser above the upper surface  104  typically ranges from 0.01 to 2 cm although risers of greater or lesser heights could be used. The riser  112  serves several functions such as shielding the upper surface  104  from unwanted scratches and providing a “bumper” that minimizes damage to the enclosed electronics if portable electronic device  100  is dropped or bumped. In a preferred embodiment of the present invention, the riser is made from molded plastic. Other materials may be used to form the riser, including rubber, wood, leather, metal, graphite or other carbon composites. 
     A second embodiment of the invention is shown in FIG.  2 ( a ). Here, the hinge  202  serves as a first riser and a grip  204  serves as a second riser. The grip  204  is used in handling the portable electronic device (as shown in FIG.  2 ( b )) and reduces the risk of dropping the device. Grip  204  is preferably detachable and can be replaced with a grip of a different color, thus creating a “fashionable” accessory for the portable electronic device. The combination of the first riser (hinge) and second riser (grip) significantly reduces scratching of the upper surface  104  because an object placed on top of the device will be displaced from the first surface. The grip  204  comprises ridges  206  that enhance traction between one&#39;s hand and the housing. The ridges  206  are orthogonal to the length of one&#39;s fingers as shown in FIG.  2 ( b ). FIG.  2 ( c ) shows a side view of the housing as shown in FIG.  2 ( a ). Here, the hinge  202  and the grip  204  are substantially the same height relative to the upper surface  104 . In an embodiment of the present invention, a complementary grip  208  may be attached in substantially the same location on the lower surface  108  of the housing as shown in FIG.  2 ( c ). 
     FIG.  3 ( a ) shows a lower cost embodiment of the present invention where support members  302  (preferably made of magnesium or other metal or metal alloy) are strategically attached to the housing  102  (which is typically made from plastic) in areas where structural support is most needed. Reducing the amount of magnesium used for the housing directly reduces manufacturing costs but by strategically placing the magnesium parts on the “plastic housing” does not significantly compromise structural integrity. For example, in FIG.  3 ( a ), the corner  304  is encased by the support member  302 . Encasing the corner as such makes the housing more rigid and difficult to twist. Note, however, that support member  302  may be formed of plastic and a selected portion of the upper surface may be a metal or metal alloy. Similarly, FIG.  3 ( b ) shows a support member  310  used to provide structural support to the housing  102  and a disk drive  308 . Additionally, the magnesium parts are aesthetically pleasing and may be formed using a magnesium alloy. The metal additives used to form the alloy may be chosen to alter the color of the part. Consequently, the part may not require painting and therefore scratching the part may not create a perception of poor quality. 
     FIG.  4 ( a ) shows an embodiment of the present invention comprising a display unit  404  and a base unit  407 . The display unit further comprises a frame  402  and a top  401 . The frame is preferably formed of magnesium or other metal or metal alloy and the top  401  is preferably made of plastic. The top  401  is inserted into the frame  402  and overlays a selected portion of frame  402  as shown in FIG.  4 ( a ). The top  401  and the frame  402  form an upper surface  405 , as shown in FIG. 4 ( a ). The top  401  in one embodiment of the present invention is preferably substantially transparent, thus adding aesthetic value to the housing. The top  401  in this embodiment is removable and can be replaced with a top of a different color. 
     A crossbeam  406  bisects four corners  408  of frame  402  shown in FIG.  4 ( b ). 
     Additionally, the frame  402  preferably comprises a slot  403  in which the top may be inserted although an embodiment has been contemplated where slot  403  is not present. FIG.  4 ( c ) shows a cross-section of a portion of the frame as shown in FIG.  4 ( b ). Here, the frame is configured in a “T” shape wherein the vertical member  410  has a first end  414  and a second end  416 . The vertical member forms a right angle with the horizontal member  412  thereby adding additional strength to the frame. 
     The structural designs shown in FIGS.  4 ( a ) and  4 ( b ) significantly strengthens the display unit  404 . The base unit  407  may be similarly strengthened by incorporating frame  504  (preferably made of magnesium or other metal or metal alloy) shown in FIG.  5 ( b ) into the base unit  407  shown in FIG.  5 ( a ). Frame  504  comprises an anchor  506  used to support the hinge  110  (shown in FIG. 5 a ). The anchor  506  contains a threaded aperture  508  to which the hinge  110  used to couple the display unit and the base unit  407  is bolted. Adding a crossbeam  510  similar to crossbeam  406  shown in FIG.  4 ( b ) may be desirable to further strengthen frame  504 . Frame  504  also contains grooves  520  to which the base unit  407  is attached. An additional advantage to using frame  504  as shown in FIG.  5 ( b ) is that a frame made out of a metal or metal alloy reduces electromagnetic interference that may be generated by electronic devices in the vicinity of the portable electronic device. The frame reflects electromagnetic waves that may otherwise interfere with the electronics of the portable electronic device. 
     FIG.  6 ( a ) shows the upper surface of the housing  104  and riser  112  previously shown in FIG.  1 ( a ). FIG.  6 ( b ) shows the upper surface where the riser  112  has been removed. The upper surface comprises apertures  606  that are selectively placed along the perimeter of the upper surface (which is preferably made of magnesium or other metal or metal alloy) although the apertures may be formed in an area of the upper surface. The apertures  602 , in addition to reducing the weight of the housing, reduces manufacturing cost because less metal is used to form the upper surface  104 .