Patent Publication Number: US-2003223797-A1

Title: Keyboard assemblies

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates to keyboard assemblies having improved resistance to liquids.  
       DESCRIPTION OF THE RELATED ART  
       [0002] Conventional keyboards for computers, phones, and other electronic devices often include barriers that provide resistance to key movement. For example, one conventional computer keyboard includes a template having a number of cups formed from rubber or plastic. When a user of this keyboard strikes the keys of the keyboard, the cups are deflected and make contact with flexible circuit board located underneath the spring template. This contact causes the flexible circuit board to send a signal to a computer connected to the computer keyboard. Users of keyboards, such as that described above, occasionally spill liquids on the keyboard. These liquids often pass through openings in the barrier or past the edges of the template such that the liquid comes in contact with the flexible circuit board or other electronic components of the keyboard, causing the keyboard to malfunction. Some have attempted to address this problem by providing aftermarket elastic covers for keyboards, such as often seen in restaurants and commercial establishments. Unfortunately, such covers interfere with key striking and quickly degrade due to repetitive use.  
       SUMMARY OF THE INVENTION  
       [0003] In light of the foregoing problems associated with conventional keyboards, generally speaking, one object of the present invention is to provide keyboard assemblies that are more resistant to spilled liquids than some conventional keyboards.  
       [0004] Other objects, advantages and features associated with the present invention will become more readily apparent to those skilled in the art from the following detailed description. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modification in various obvious aspects, all without departing from the invention. Accordingly, the drawings and the description are to be regarded as illustrative in nature, and not limitative. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0005]FIG. 1 is a perspective view of a keyboard assembly in accordance with one embodiment of the present invention.  
     [0006]FIG. 2 is an exploded view of the keyboard assembly illustrated in FIG. 1.  
     [0007]FIG. 3 is a rear perspective view of an upper portion of the housing of the keyboard assembly illustrated in FIG. 1.  
     [0008]FIG. 4 is a rear view of a modular key assembly of the keyboard assembly illustrated in FIG. 1.  
     [0009]FIG. 5 is a side view of the modular key assembly illustrated in FIG. 4.  
     [0010]FIG. 6 is a top view of a key of the keyboard assembly illustrated in FIG. 1.  
     [0011]FIG. 7 is a front view of the key illustrated in FIG. 6.  
     [0012]FIG. 8 is a side view of the key illustrated in FIG. 6.  
     [0013]FIG. 9 is a bottom view of the key illustrated in FIG. 6.  
     [0014]FIG. 10A is a partial operational view of a key about to deforming a deformable member of a liquid resistant barrier of the keyboard assembly illustrated in FIG. 1.  
     [0015]FIG. 10B is a partial operational view of the key of FIG. 10A after it has deformed the deformable member of the liquid resistant barrier and switched a switch of a circuit board of the keyboard assembly illustrated in FIG. 1.  
     [0016]FIG. 11 is a partial top view of a bottom portion of the housing of the keyboard assembly illustrated in FIG. 1, where the liquid resistant barrier covers the circuit board.  
     [0017]FIG. 12 is a cross-sectional view of the partial assembly illustrated in FIG. 11 taken along the line  12 - 12  of FIG. 11.  
     [0018]FIG. 13 is an enlarged view of a drain channel in the bottom portion of the housing of the keyboard assembly illustrated in FIG. 1, where the drain channel communicates an interior area of the keyboard assembly with an area external of the keyboard assembly.  
     [0019]FIG. 14 is a perspective view of an alternative embodiment of a liquid resistant barrier usable with the keyboard assembly illustrated in FIG. 1.  
     [0020]FIG. 15 is a perspective view of an alternative embodiment of a liquid resistant barrier usable with the keyboard assembly illustrated in FIG. 1.  
     [0021]FIG. 16 is a perspective view of an alternative embodiment of a liquid resistant barrier usable with the keyboard assembly illustrated in FIG. 1.  
     [0022]FIG. 17 is a perspective view of an alternative embodiment of a keyboard assembly in accordance with another embodiment of the present invention.  
     [0023]FIG. 18 is a perspective view of a liquid resistant barrier of the keyboard assembly illustrated in FIG. 17.  
     [0024]FIG. 19 is a rear perspective view of an upper portion of a keyboard assembly in accordance with a further embodiment of the present invention.  
     [0025]FIG. 20 is a perspective view of a liquid resistant barrier of the keyboard assembly illustrated in FIG. 19.  
     [0026]FIG. 21 is a rear perspective view of an upper portion of a keyboard assembly in accordance with another embodiment of the present invention.  
     [0027]FIG. 22 is a perspective view of a liquid resistant barrier of the keyboard assembly illustrated in FIG. 21.  
     [0028]FIG. 23 is a partial, exposed view of a keyboard assembly in accordance with another embodiment of the present invention.  
     [0029]FIG. 24 is an exploded view of a keyboard assembly in accordance with another embodiment of the present invention.  
     [0030]FIG. 25 is a perspective view of a keyboard assembly in accordance with another embodiment of the present invention.  
     [0031]FIG. 26 is a cross-sectional view of the upper portion of the keyboard assembly illustrated in FIG. 25 taken along the line  26 - 26  in FIG. 25.  
     [0032]FIG. 27 is a cross-sectional view of the upper portion of the keyboard assembly illustrated in FIG. 25 taken along the line  27 - 27  in FIG. 25.  
     [0033]FIG. 28 is a partial cross-sectional view of an alternative embodiment of the upper portion of the keyboard assembly illustrated in FIG. 25. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0034] FIGS.  1 - 26  illustrate embodiments of keyboard assemblies  100 ,  200 ,  300 ,  400 ,  500 ,  600 ,  700  in accordance with embodiments of the present invention. As described below, the keyboard assemblies  100 ,  200 ,  200 ,  400 ,  500 ,  600 ,  700  are each configured to lessen the chance that any liquid spilt on the keyboard assembly will contact the electrical components thereof. Because the keyboard assemblies  100 ,  200 ,  300 ,  400 ,  500 ,  600 ,  700  are functionally similar and share a number of similar parts, in the following description like numbered parts of the keyboard assemblies  100 ,  200 ,  300 ,  400 ,  500 ,  600 ,  700  are referred to by like numbers, increased by 100&#39;s and/or followed by primes (′) or letters (a, b, c).  
     [0035] As illustrated in FIG. 1, the keyboard assembly  100  is a device having a plurality of keys  102  that a user strikes when operating the keyboard assembly  100 . The keyboard assembly  100  may be a keyboard for a personal computer, a calculator, a laptop computer, a personal digital assistant, a cellular phone, a desktop phone, a register, or other electronic device having keys.  
     [0036] The illustrated keyboard assembly  100  includes a housing  103  having an upper portion  104  and a lower portion  105 . In alternative embodiments, the housing  103  may be defined by more or less portions and by differently divided portions. For example, the housing  130  may have lateral halves. In the illustrated embodiment, the upper portion  104  of the housing  103  includes an upper side  106  that typically faces a user of the keyboard assembly  100  during operation of the keyboard assembly  100 . Likewise, the bottom portion  105  of the housing  103  has a bottom side  107  that is located opposite from the upper side  106  and is the surface upon which the keyboard assembly  100  typically rests when a user strikes the keys  102 . In one embodiment where the keyboard assembly  100  is a keyboard for a personal computer, the keys  102  are arranged in the conventional Qwerty or Dvorak format. In another embodiment, the keys  102  are arranged in a four by three grid, such as on a telephone. The keys  102  have illustrations thereon, such as the illustrated alphanumeric characters.  
     [0037] As is illustrated in FIGS.  6 - 9 , the keys  102  are of a conventional format, preferably each having a non-resilient (stiff) strike portion  110  and a protrusion  109 . The protrusion  109  includes retaining clips  111  that retain the key in the keyboard assembly  100  as described below.  
     [0038] As is illustrated in the exploded view of FIG. 2, the upper portion  104  of the housing  103  includes a plurality of openings  108   a,    108   b  in which the keys  102  are located. In an alternative embodiment, the upper portion  104  has only one opening  108   b.  The openings  108   a,    108   b  are conduits that pass through the housing  103  and are sized to receive a portion of a single key or are sized to receive multiple keys. For example, in the illustrated keyboard assembly  100 , the upper portion  104  includes four openings  108   a  that each receive the protrusion  109  of a single key  102 . When assembling the keyboard assembly  100 , the retaining clips  111  of each key  102  snap into one of the openings  108   a  so as to moveably retain the key in the respective opening  108   a.  In this manner, each opening  108   a  accommodates movement of one key  102 . Hence, FIG. 3 illustrates each of the openings accommodating the respective protrusion  109  of a key  102 .  
     [0039] As is also illustrated in FIGS.  2 - 5 , the opening  108   b  is sized to receive a plurality of keys  102  (at least two). More specifically, the opening  108   b  receives a modular key assembly  120  having a number of keys  102  thereon. The modular key assembly  120  includes a base plate  122  having a number of openings therein that are similar to the openings  108   a  in the upper portion  104 . Each of the openings in the base plate  122  receives the protrusion  109  and retaining clips  111  of a single key  102  so as to moveably retain the received key in the opening of the base plate. As is illustrated in FIG. 5, each of the keys  102  is freely moveable in the openings of the base plate  122 . That is, the keys  102  are not biased in any direction of movement. For purposes of illustration, the top two keys  102  in FIG. 5 have not be depressed, while the bottom key in FIG. 5 has been depressed such that the protrusion  109  protrudes through the base plate  122 . As will be apparent, the keys  102  in the openings  108   a  move with respect to the upper portion  104  of the housing  103  in a similar manner.  
     [0040] When the keys  102  are retained in the base plate  122  to define the modular key assembly  120 , the modular key assembly, or at least a portion thereof, is inserted into the opening  108   b  of the upper portion  104  of the housing  103 . The modular key assembly  120  is retained in the opening  108   b  by one or more clips, screws, snaps, press fits, ledges, locators or other devices of the modular key assembly and/or the housing  103 . Because the modular key assembly  120  is located in the opening  108   b,  the keys  102  are also located in the opening  108   b.  In this manner, the opening  108   b  accommodates movement of a plurality of keys  102 .  
     [0041] As is apparent, the keys  102  can be retained to the keyboard  100  in other manners, such as those described in U.S. Pat. Nos.: 3,736,397; 4,362,408; 4,791,257; 4,906,117; and 5,676,476, the entire disclosures of which are hereby incorporated by reference.  
     [0042] The keyboard assembly  100  also includes a liquid resistant barrier  130 , which is illustrated in FIGS. 2, 10A,  10 B,  11 , and  12 . The liquid resistant barrier  130  is a sheet-like member formed of a material that has the capacity to resist the passage of inert liquids therethrough, such as water based liquids commonly spilled on keyboards. As is illustrated in the Figures, the liquid resistant barrier  130  includes a plurality of deformable members  132  that protrude from an upper surface  166  of the barrier.  
     [0043] When the liquid resistant barrier  130  is located in the keyboard assembly  100 , the deformable members resist movement of the keys. That is, one or more of the deformable members  132  is disposed directly adjacent the protrusion  109  (or other intermediary member) such that when a user strikes a key  102 , the deformable member resists movement of the key. For example, FIG. 10A illustrates a key  102  located directly adjacent a deformable member  132  prior to a user striking the key; the deformable member  132  is resisting movement of the key to keep the key in the static position illustrated in FIG. 10A. When a user strikes the key  102  with sufficient force to overcome the resistance of the deformable member  132 , the deformable member will deform as illustrated in FIG. 10B. When the user removes the striking force, the deformable member and the adjacent key  102  will return to the static positions illustrated in FIG. 10A.  
     [0044] The liquid resistant barrier  130  and its deformable members  132  are preferably constructed of a liquid resistant and elastomeric material having a suitable durometer or hardness necessary to achieve a desired keystroke resistance. For example, the liquid resistant barrier may be constructed, i.e., molded, cast, stamped, woven, etc., from a polymeric material, such as polyurethane, polypropylene, polyethylene, equivalents of these materials, and blends of these materials. Additionally, the liquid resistant barrier may be constructed of a synthetic or natural rubber. The liquid resistant barrier may also be fabricated from a conductive elastomeric material. In a further embodiment, the liquid resistant barrier  130  is formed from a combination of materials, such as a woven nylon sheet having polyethylene deformable members  132  secured thereto. The deformable members  132  of the liquid resistant barrier  130  may be similar to that described in WO 00/73078 A1 and U.S. Pat. Nos. 5,494,363, 5,588,760 and 5,933,133, the entire disclosures of which are hereby incorporated by reference. In a preferred embodiment, the liquid resistant barrier  130  is the only device that resists movement of the keys  102 . That is, the keyboard assembly  100  preferably does not include any other devices besides the deformable members  132  of the liquid resistant barrier  130  that resist striking movement of the keys  102 . However, in alternative embodiments, movement of the keys  102  is resisted by devices in addition to the deformable members  132  of the liquid resistant barrier  130 . For example, movement of the keys  102  may also be resisted by one or springs or pads, such as that described in some the earlier referenced patent publications.  
     [0045] As is also illustrated in FIGS. 2, 1A,  10 B,  11 , and  12 , a circuit board  140  is located directly underneath the liquid resistant barrier  130 . Hence, the liquid resistant barrier  140  is located between the keys  102  and the circuit board  140 . The circuit board  140  is of a conventional construction and has a plurality of switches  142  that are switched, i.e. tripped or closed, when the deformable member contacts the circuit board as illustrated in FIG. 10B. When the deformable member  132  contacts the circuit board  140 , a signal is sent via the circuits of the circuit board  140 . In one embodiment, the circuit board  140  is a flexible membrane type circuit board, which is widely employed in the keyboards of personal computers, such as those illustrated in U.S. Pat. Nos. 5,434,566 and 5,588,760, the entire disclosure of which are hereby incorporated by reference. A suitable flexible membrane type circuit board includes two flexible films on which electrical contacts are formed in opposed relation with a spacer barrier therebetween. The spacer barrier includes a number of holes therethrough that are located at positions corresponding to the contacts of the respective barriers. When a key  102  deforms the deformable member  132 , the deformable member will cause the opposed electrical contacts to touch and close the switch. In a further embodiment, the circuit board  142  is a single barrier type circuit board, and each deformable member has a conductive insert therein or is formed of a conductive material. When the conductive insert or the conductive deformable member contacts the barrier, it creates an electrical contact to switch one of the switches  142 . An example of this type of circuit board is described in U.S. Pat. No. 5,494,363, the entire disclosure of which is also hereby incorporated by reference.  
     [0046] As is illustrated in FIG. 2, the switches  142  of the circuit board  140  are connected via conductive lines or patterns to connecting lines  143  of a tongue  144  in the conventional manner. As is known, each switch  142  is corresponds to a specific key  102 , depending upon the each keys respective position. The connecting lines  143  of the tongue  144  are in turn connected to a printed circuit board  146  or equivalent device, which translates the signals from the switches  142  in any one of a variety of conventional manners. The printed circuit board  146  is in turn connected to an electronic cord that protrudes from the keyboard assembly  100 . In alternative embodiments, the keyboard assembly is battery powered, has a wireless communication link with an associated device, such as a computer, and does not have the illustrated electronic cord.  
     [0047] In the keyboard assembly  100 , the liquid resistant barrier  130  (located between the keys in the openings  108   a,    108   b  and the circuit board  140 ) and the housing  103  are configured such that any liquid that passes through the openings  108   a,    108   b  is directed to an area external of the keyboard assembly when the bottom surface  107  of the keyboard assembly is horizontal, such as when resting upon a flat and level surface S. This directing of the liquid is achieved by using the assistance of gravity to direct the liquid along the liquid resistant barrier  130  to one or more drain channels  150  of the keyboard assembly  100 . In the illustrated embodiment, the liquid resistant barrier  130  and the circuit board  140  are at an incline with respect to the flat and level surface S upon which the bottom surface  107  rests. As is best illustrated in FIG. 12, the lower portion  105  of the housing  103  includes a support  152 , which may be part of the lower portion  105  and/or a separate intermediate member, upon which the circuit board  140  and the liquid resistant membrane rests. Because the support  152  is at an incline with respect to horizontal, the liquid resistant barrier  130  is also at an incline. Hence, when liquid passes through the openings  180   a,    180   b,  the liquid is directed via gravity in the direction A generally toward the lower most edge  153  of the bottom housing  105  where a well  154  is located. The well  154  is a recess, groove, indentation, channel, or other area configured to receive liquid directed by the liquid resistant barrier  130  and is at a lower elevation than at least a portion of the liquid resistant barrier, preferably at a lower elevation than a lower most edge of the liquid resistant barrier.  
     [0048] As is also illustrated in FIGS. 1, 2,  11 ,  12 , and  13 , the bottom portion  105  of the housing  103  includes three drain channels  150 , which are openings, passageways, conduits, or similar throughways that communicate the area external of the keyboard assembly  100  with the location in the housing  103  where the liquid is directed by the liquid resistant barrier  130 . Like the well  154 , the drain channels  150  are also at a lower elevation than at least a portion of the liquid resistant barrier, preferably at a lower elevation than a lower most edge of the liquid resistant barrier. In the illustrated embodiment, the liquid is directed by the liquid resistant barrier  130  to the lower most edge  153  where the well  154  is located. Because the drain channels  150  are located at the lower most edge  153  of the bottom portion  105 , directly adjacent the well  154 , liquid that has passed through the openings  108   a,    108   b  will flow along the liquid resistant barrier  130  to the well  154  and then drain out of the keyboard assembly  100  via one or more of the drain channels  150 . In this manner, the liquid resistant barrier  130  and the housing  103  are configured such that liquid that has passed through the openings  108   a,    180   b  is directed to an area external of the keyboard assembly when the keyboard assembly  100  is resting upon the bottom surface  107 . In an alternative embodiment, the keyboard assembly  100  includes only one drain channel. In a further embodiment, the keyboard assembly  100  does not include the well  154 . Rather, the edge of the liquid resistant barrier  130  terminates at the wall of the housing in which the drain channel is located such that the liquid is directed by the liquid resistant barrier directly to the drain channel.  
     [0049] As is illustrated in FIG. 11, to further reduce the possibility that liquid will not contact the switches  142  of the circuit board, the liquid resistant barrier  130  covers an entirety of the circuit board  140 . That is, the liquid resistant barrier  130  extends beyond a peripheral edge or perimeter  141  of the circuit board  140  such that the perimeter of the liquid resistant barrier encompasses the perimeter  141  of the circuit board. Additionally, to further reduce the possibility that liquid will contact the switches  142  and other electrical components, the liquid pervious barrier  130  extends past the edge  141  of the circuit board  140  to such an extent that the barrier also covers the printed circuit board  146 .  
     [0050] In the illustrated embodiment, the liquid resistant barrier  130  contacts the interior surface of three walls  156  of the housing  103 , but does not contact the wall  157  through which the drain channels  150  pass such that liquid that is directed toward the wall  157  falls into the well  154 . Hence, when liquid passes through the openings  108   a,    108   b,  it will fall onto the liquid resistant barrier  130  and be directed toward the drain channels  150 , rather than contacting and possibly damaging the printed circuit board  146  and/or the switches  142  of the circuit board  140 . In an alternative embodiment, the liquid resistant barrier  130  contacts all four walls  156 ,  157  and has openings passing through the barrier directly above the well  154  such that liquid directed toward the wall  157  drops through the openings of the barrier and into the well.  
     [0051] In a further embodiment, a liquid impervious seal is defined between the liquid resistant barrier  130  and the walls  156 , such as by a press fit or by an adhesive. The liquid resistant barrier  130  is preferably continuous, i.e., devoid of any holes or openings passing therethrough, at least in an area of the liquid resistant barrier that covers the circuit board  140 . In the illustrated embodiment, the liquid resistant barrier is continuous across an entirety of the liquid resistant barrier. In an alternative embodiment, the liquid resistant barrier  130  includes openings passing therethrough in the area of the barrier that does not cover the circuit board. In a further embodiment, the liquid resistant barrier  130  includes openings that sealingly receive mounting pegs, pins, or other protrusions such that liquid is prevented from passing through such openings.  
     [0052] The liquid resistant barrier  130  need not contact the walls  156  to still fall within the confines of an embodiment of the present invention. For example, in an alternative embodiment of the keyboard assembly  100 , the liquid resistant barrier  100  does not extend to the walls  156 , but is rather located only underneath the openings  108   a,    108   b.  For example, FIGS. 14 and 15 illustrate alternative embodiments of two liquid resistant barriers  130 ′,  130 ″ of the keyboard assembly  100 . The liquid resistant barrier  130 ′ is configured to fit directly underneath the opening  180   a  of the upper housing  104  and has a perimeter  160 ′ that encompasses all of the openings  180   a  when located directly underneath the openings  180   a.  Likewise, the liquid resistant barrier  130 ″ is configured to fit directly underneath the opening  180   b  of the upper housing  104  and has a perimeter  160 ″ that is larger than the perimeter  164  of the opening  180   b  so as to encompass the perimeter of the opening  180   b.  Each of the liquid resistant barriers  130 ′  130 ″ have upper surfaces  166 ′,  166 ″ that are sloped, i.e., deviate from horizontal, as measured with respect to a base surface  167 ′,  167 ″ of the respective barrier. In the illustrated embodiment, the upper surfaces  166 ′,  166 ″ curvilinearly slope toward a center area  168 ′,  168 ″ of the respective barrier such that liquid that passes through each opening  180   a,    180   b  and falls on each barrier  130 ′,  130 ″ is directed toward the center area of the liquid resistant barrier. When located in the keyboard assembly  100  in lieu of the liquid resistant barrier  130 , the liquid resistant barriers  130 ′,  130 ″ do not cover the entire peripheral edge  141  of the circuit board  140  and do not contact the inner walls  156  of the housing  103 , but are still located so as to catch liquid that falls through the openings  180   a,    180   b  when the keyboard assembly  100  rests upon the planar and level surface S. Liquid that passes through the openings  108   a,    108   b  when the keyboard assembly  100  is resting upon the surface S will be directed to the center areas  168 ′,  168 ″ via the sloped walls  166 ″,  166 ″, to the well  154 , and then out of the keyboard assembly via a drain channels  150 .  
     [0053] As will be appreciated, the drain channels  150  can be located at other locations of the housing  103  and the liquid resistant barrier  130  can be inclined at various degrees and in various directions toward such drain channels. For example, in one embodiment, the drain channels  150  are located at a lower most edge of the bottom housing  105  that is opposite from the front lower most edge  153 . In this embodiment, the liquid resistant barrier  130  is inclined toward the rear lower most edge so as to direct liquid that has passed through the openings  108   a,    108   b  to such located drain channels. In addition, the base  152  of the housing need not be inclined with respect to horizontal. For example, the base  152  upon which the liquid resistant barrier  130  and the circuit board  140  rest may be parallel with horizontal. To achieve an incline to direct liquid to the drain channel of the housing  103 , the upper surface  166  of the liquid resistant barrier  130  may be contoured to create an incline. For example, FIG. 16 illustrates an alternative liquid resistant barrier  130 ′″ of the keyboard assembly  100 , where the upper surface  166 ′″ of the liquid resistant barrier  130 ′″ is an incline to direct liquid toward the well  154  and drain channels  150 .  
     [0054] Although the above described embodiments of the present invention are well suited for keyboard assemblies  100  that rest upon the planar and level surface S during normal operation, such as is the case with computer keyboards, telephones, registers, etc., some keyboard assemblies are manipulated such that more protection is beneficial. For instance, some keyboard assembly are used in environments where the keyboard assembly is vibrated, inclined with respect to horizontal, and/or continuously moved, such as is the case with cellular telephones. In these instances, it is desirable to have greater protection from liquid that might enter the openings  180   a,    180   b.  FIGS.  17 - 23  illustrate keyboard assemblies  200 - 500  in accordance with further embodiments of the present invention that are suitable for such environments.  
     [0055]FIGS. 17 and 18 illustrate another embodiment of a keyboard assembly  200  in accordance with the present invention. The keyboard assembly  200  is similar to the keyboard assembly  100  in all respects. Hence, the liquid resistant barrier  230  includes a plurality of deformable members  232 . However, in the keyboard assembly  200 , a seal is defined between the liquid resistant barrier  230  and the housing  203  to prevent the passage of liquid between the housing and the barrier such that liquid that enters the key openings of the housing  203  is prevented from contacting the switches of the circuit board located underneath the liquid resistant barrier  230 . In the embodiment illustrated in FIGS. 17 and 18, the liquid resistant barrier  230  includes a lip  270  that is raised with respect to the upper surface  266  of the liquid resistant barrier  230  to define a recess or well in which to catch liquid that has passed through the key openings in the housing  203 . As is illustrated in FIG. 17, the lip  270  of the liquid resistant barrier  230  is sandwiched or squeezed between the opposing outer edges  272 ,  274  of the upper and lower portions of the housing  203  to define a seal between the liquid resistant barrier  230  and the housing. Hence, the liquid resistant barrier  230  defines a complete barrier between the key openings and the electrical components of the keyboard assembly. Liquid that enters the key openings is collected by the recess of the liquid resistant barrier  230 , but is not drained from the housing  203  of the keyboard assembly  200  via drain channels. Rather, the liquid is retained in the resistant barrier  230  where it will harmlessly evaporate. Additionally, a user of the keyboard assembly  200  may rotate the keyboard assembly to discharge the liquid from the recess of the liquid resistant barrier  230  back through the key openings of the housing  203 .  
     [0056]FIGS. 19 and 20 illustrate a further embodiment of a keyboard assembly  300  in accordance with the present invention. For purposes of illustration, only the upper portion  304  of the housing  303  is illustrated along with the liquid resistant barriers  330   a,    330   b.  As is illustrated in FIG. 20, the liquid resistant barriers  330   a,    330   b  are entirely planar except for the deformable members  332   a,    332   b  protruding from the upper surface  366   a,    366   b  thereof. The planar upper surfaces  366   a,    366   b  of each liquid resistant barrier  330   a,    330   b  are sized to abut correspondingly sized walls or lips  378   a,    378   b  of the upper portion  304  of the housing  303 . That is, when the keyboard assembly  300  is assembled, the perimeter of the liquid resistant barrier  330   a  encompasses the perimeter of the lip  378   a,  and the perimeter of the liquid resistant barrier  330   b  encompasses the perimeter of the lip  378   b  and the opening  308   b.  As is illustrated in FIG. 19, the first lip  378   b  protrudes from the interior of the upper housing  304  and surrounds the perimeter of the opening  308   b;  the second lip  378   a  protrudes from the interior of the upper housing  304  and surrounds the perimeters of the openings  308   a.  When the keyboard assembly  300  is assembled, the upper surface  366   a  of the liquid resistant barrier  330   a  abuts the lip  378   a  to define a seal between the liquid resistant barrier  330   a  and the upper portion  304  of the housing  303  that does not permit liquid to pass thereby. The seal may be defined with an adhesive or similar material by a press fit between the upper portion and the lower portion of the housing  303 , and/or by a weld. A similar seal is defined between the lip  378   b  and the second liquid resistant barrier  330   b  to prevent the passage of liquid between the housing and the barrier.  
     [0057]FIGS. 21 and 22 illustrate a further embodiment of a keyboard assembly  400  in accordance with the present invention. For purposes of illustration, only the upper portion  404  of the housing  403  is illustrated along with the liquid resistant barrier  430 . As is illustrated in FIG. 22, the liquid resistant barrier  430  is entirely planar except for the deformable members  432  protruding from the upper surface  466  thereof. The planar upper surface  466  of the liquid resistant barrier  430  is sized to abut correspondingly sized walls or lips  478  of the upper portion  404  of the housing  403 . That is, when the keyboard assembly  400  is assembled, the perimeter of the liquid resistant barrier  430  encompasses the perimeter of the lip  478 . As is illustrated in FIG. 21, the lip  478  protrudes from the interior of the upper housing  404  and surrounds the perimeters of the openings  408   a.  When the keyboard assembly  400  is assembled, the upper surface  466  of the liquid resistant barrier  430  abuts the lip  478  to define a seal between the liquid resistant barrier  430  and the upper portion  404  of the housing  403  that does not permit liquid to pass thereby. The seal may be defined with an adhesive or similar material by a press fit between the upper portion and the lower portion of the housing  403 , and/or by a weld.  
     [0058]FIG. 23 illustrates another embodiment of a keyboard assembly  500  in accordance with the present invention. For purposes of illustration, the keys and/or modular key assembly of the keyboard assembly  500  have been omitted. Like the keyboard assembly  100 , the keyboard assembly  500  includes a housing having an upper portion  504  and a lower portion  505 . The upper portion  504  of the housing includes an openings  508  in which the keys are located. The keyboard assembly  500  also includes a liquid resistant barrier  530  having a plurality of deformable members  532  that resist movement of the keys. A circuit board  540  is located directly underneath the liquid resistant barrier  530 . When a key deforms one or more deformable members  532 , the deformable member will close a switch of the circuit board  640 . Similar to the embodiments illustrated in FIGS.  19 - 22 , a seal is defined between the upper portion  504  of the housing  503  and the liquid resistant barrier  530 . However, in this embodiment, the lip  578  of the upper portion  504  of the housing includes drain channels  580  through which liquid that has passed through the openings  508   a,    508   b  may drain from the sealed area within the housing. The lower portion  505  of the housing includes a support or protrusion  552  upon which the circuit board  540  and the liquid resistant barrier rest. Because the support  552  is at an incline with respect to horizontal, the liquid resistant barrier  530  is also at an incline. Hence, the liquid resistant barrier  530  and the circuit board  540  are at an incline with respect to the flat and level surface upon which the keyboard assembly rests such that liquid that has passed through the opening  508  is directed via gravity toward the drain channels  580 . Similar to the embodiment illustrated in FIGS.  1 - 12 , liquid that drains from the separate drain channels  580  will enter into the well  554  within the lower portion  505  of the housing  503  and eventually drain from drain channels  550  at the corners of the lower portion of the housing.  
     [0059]FIG. 24 illustrates another embodiment of a keyboard assembly  600  in accordance with the present invention. Like the keyboard assembly  100 , the keyboard assembly  600  includes a plurality of moveable keys  602  and a housing having an upper portion  604  and a lower portion  605 , where the upper portion  604  of the housing includes an upper side  606  that faces a user of the keyboard assembly  600  during operation of the keyboard assembly  100  and the bottom portion  605  of the housing has a bottom side  607  upon which the keyboard assembly  600  typically rests when a user strikes the keys  102 . The upper portion  604  of the housing includes a plurality of openings  608   a,    608   b  in which the keys  602  are located. The opening  608   b  receives a modular key assembly  620  having a number of keys  602  thereon.  
     [0060] The keyboard assembly  600  also includes a liquid resistant barrier  630  having a plurality of deformable members  632  that protrude from an upper surface  666  of the barrier and resist movement of the keys  602 . A circuit board  640  is located directly underneath the liquid resistant barrier  630 . When a key  602  deforms one or more deformable members  632 , the deformable member will close a switch  642  of the circuit board  640 . The connecting lines of the circuit board  640  are connected to a printed circuit board  646  or equivalent device. As is illustrated in FIG. 24, the liquid resistant barrier  630  is contoured in the shape of a pan or cap such that it has a recess that receives the circuit board  640  and printed circuit board  646 . Hence, the liquid resistant barrier  630  receives and overlaps the perimeter  641  of the circuit board  640 . The lower portion  605  of the housing includes a support or protrusion  652  upon which the circuit board  640  and the liquid resistant barrier rests. Because the support  652  is at an incline with respect to horizontal, the liquid resistant barrier  630  is also at an incline. Hence, the liquid resistant barrier  630  and the circuit board  640  are at an incline with respect to the flat and level surface upon which the bottom surface  607  rests such that liquid that has passed through the openings  608   a,    608   b,  is directed via gravity toward the lower most edge of the lower portion  605  where drain channels  650  are located.  
     [0061] FIGS.  25 - 27  illustrate another embodiment of a keyboard assembly  700  in accordance with the present invention. The keyboard assembly  700  is a keyboard for a personal computer and has a plurality of keys  702  arranged in the conventional Qwerty or Dvorak format that a user strikes when operating the keyboard assembly  700 . The keys  702  are of a conventional format, preferably each having a strike portion and a protrusion with retaining clips (not illustrated). In the illustrated embodiment, the keyboard assembly  700  includes a liquid resistant barrier therein having a plurality of deformable members, such as one of those described above. In an alternative embodiments, the keyboard assembly  700  does not include a liquid resistant barrier therein having a plurality of deformable members. The keyboard assembly  700  also includes a circuit board of a conventional construction that has a plurality of switches that are switched when the keys  702  are actuated.  
     [0062] The keyboard assembly  700  includes a housing  703  having an upper portion  704  and a lower portion  705 . The upper portion  704  of the housing  703  includes an upper side  706  that typically faces a user of the keyboard assembly  700  during operation of the keyboard assembly. The bottom portion  705  of the housing  703  has a bottom side  707  that is located opposite from the upper side  706  and is the surface upon which the keyboard assembly  700  typically rests when a user strikes the keys  702 . At least a portion of the bottom side  706  defines a lower-most elevation of the housing when the keyboard assembly is resting upon the bottom side. For example, the bottom side  706  may have a surface defined by legs, posts, or another area that rest upon a surface when a user is using the keyboard assembly  700 . As is illustrated in FIGS.  25 - 27 , the upper portion  704  of the housing  703  has two recessed surfaces  712   a,    712   b  that each are recessed from the upper side  706  of the upper portion  704  to define two recesses  701   a,    701   b  in the upper side of the housing. A plurality of members  713  protrude from each recessed surface  712   a,    712   b.  In the illustrated embodiment, the members  713  are cylindrical protrusions that are elevated from the recessed surfaces  712   a,    712   b.  Each member  713  includes an opening  708  that passes through a wall  714  of the upper portion  704  of the housing  703 . Each opening  708  is sized to receive the protrusion of a key  702  so as to moveably retain the key in the opening.  
     [0063] In an alternative embodiment, the recesses  701   a,    701   b  are combined to define one recess in the upper side of the housing  703 . In a further embodiment, the upper portion  704  of the keyboard assembly  700  includes one or more members  713  that protrude from the recessed surface  712   a  and that each have a plurality of openings  708  passing therethrougb. For example, in one embodiment the keyboard assembly  713  includes only one member  713  in the form of a rectangular or a stepped block that is elevated from the recessed surface  712   a  and that has a number of openings  708  passing therethrough.  
     [0064] Liquids that are spilled on the keyboard assembly  700  are generally received by the recesses  701   a,    701   b.  Rather than accumulate in the recesses  701   a,    701   b,  enter the openings  708 , and cause damage to the internal components of the keyboard assembly  700 , the keyboard assembly  700  includes drain channels  750   a,    750   b  that permit liquid in the recesses  701   a,    701   b  to drain from the keyboard assembly when the keyboard assembly is resting upon the bottom side  707 . In the illustrated embodiment, the drain channels  750   a  are grooves or indentations in the uppers side  706  that extend from one edge  718  of the recess  701  to one of the transverse sides  715  of the housing  703 . Hence, each drain channel  750   a  fluidly communicates an area external of the keyboard assembly  700  with the recess  701   a.  The drain channels  750   b  are configured the same as the drain channels  750   a  and fluidly communicate the recess  701   b  with the recess  701   a  such that fluid spilled in the recess  701   b  drains via the drain channels  750   b  into the recess  701   a  where it is communicated to the area external of the keyboard assembly by the drain channels  750   a.    
     [0065] As is best illustrated in FIG. 27, a lower most surface  717  of each drain channel  750   a  is preferably at a lower elevation than the upper side  706 , and more preferably at a lower elevation than the recessed surface  712  as measured with respect to the bottom side  707  such that liquid in the recess  701  tends to flow out of the recess into the drain channel and out of the keyboard assembly by the force of gravity when the bottom side rests upon a planar and horizontal surface. Likewise, a lower most surface of each drain channel  750   b  is preferably at a lower elevation than the upper side  706 , and more preferably at a lower elevation than the recessed surface  712   b  as measured with respect to the bottom side  707  such that liquid in the recess  701   b  tends to flow out of the recess into the drain channels  750   b  to the drain channels  750   a  and thereafter out of the keyboard assembly by the force of gravity.  
     [0066] In the preferred embodiment, the recessed surface  712   a  of the recess  701   a  is inclined toward the drain channels  750   a  as measured with respect to horizontal when the bottom side  707  of the keyboard assembly is resting upon a planar and horizontal surface. Likewise, the recessed surface  712   b  of the recess  701   b  is inclined toward the drain channels  750   b  as measured with respect to horizontal when the bottom side  707  of the keyboard assembly is resting upon a planar and horizontal surface. Hence, any liquid in the recesses  701   a,    701   b  tends to flow along the recessed surfaces  712   a,    712   b  toward the drain channels  750   a,    750   b.  In this manner, the housing  703  is configured such that liquid that has fallen in the recesses  701   a,    701   b  is directed to an area external of the keyboard assembly  700  when the keyboard assembly is resting upon the bottom surface  707 .  
     [0067] In an alternative embodiment, the recess  701   b  drains via separate drain channels to another one of the transverse sides  715  rather than to the recess  701   a.  That is, in this alternative embodiment, the recess  701   b  is not in communication with the recess  701   a  via the drain channels  750   b.  Rather, the recess  701   b  drains directly to an area external of the keyboard assembly  700  via drain channels configured similar to the drain channels  750   a  associated with the recess  701   a.    
     [0068] As described above, the drain channels  750   a,    750   b  are grooves or indentations in the upper side  706  of the upper portion  704 . These drain channels  750   a,    750   b  are preferably formed when molding the upper portion  704  of the keyboard from a plastic material. However, in alternative embodiments, the drain channels  750   a,    750   b  may take other configurations and may be fabricated in other manners. For example, in one embodiment the drain channels  750   a,    750   b  are cylindrical conduits defined my molding or machining and which are located underneath the upper side  706  (when the bottom side  707  is resting upon a flat and planar surface). In a further embodiments, the drain channels  750   a,    750   b  are at least partially defined by the lower portion  705  of the housing. For example, in one embodiment, one or more througholes in the recess  701   a  communicate liquid in the recessed surface  712   a  of the recess with a channel in the lower portion  705 , which in turn is in communication with the area external of the keyboard assembly  700 .  
     [0069] In the illustrated embodiment, the upper-most surface  716  of each member  713  is located approximately 10 mm from the recessed surfaces  712   a,    712   b  of the respective recesses  701   a,    701   b.  Likewise, the upper side  706  of the upper portion  704  of the housing  703  is located approximately 10 mm from the recessed surfaces  712   a,    712   b.  Hence, the upper-most surface  716  of each member and the upper side  706  are at approximately the same elevation as measured with respect to the recessed surfaces  712   a,    712   b  of the respective recesses  701   a,    701   b.  In an alternative embodiment, the upper-most surface  716  of each member is located below the upper side  706  as measured with respect to the respective recessed surface  712   a,    712   b.  In a further embodiment of the keyboard assembly  700  illustrated in FIG. 28, the members  713 ′ protrude from the recessed surface  712   a ′ to an elevation located above the upper side  706 ′ as measured with respect to the recessed surface  712   a ′ when the keyboard assembly  700  is resting upon the bottom side. Hence, the distance Y between the upper-most surface  716 ′ of each member  713 ′ and the recessed surface  712   a ′ is greater than the distance X between the upper side  706 ′ and the recessed surface  712   a ′. That is, the upper-most surface  716 ′ of each member  713 ′ is located above the upper side  706 ′ of the upper housing  704 ′ as measured with respect to the recessed surface  712   a ′ when the bottom side of the housing is resting upon a planar and horizontal surface. For example, in one embodiment the upper most surface  716 ′ of each member  713 ′ is between 0.5-5 mm above the upper side  706 ′. In one particular embodiment, Y is 10 mm, and X is 9 mm such that the difference between the distances X and Y is 1 mm. In a further embodiment of the keyboard assembly illustrated in FIG. 28, the keyboard assembly does not include any drain channels. That is, because the distance Y is greater than X, the inlet into the openings  708 ′ is located above the upper side  706 ″ when the bottom surface of the keyboard is resting on a planar and horizontal surface such that any liquid that falls into the recess  701   a ′ in sufficient quantity as to fill the recess will flow over the upper side  706 ′ and over the transverse sides  715 ′ rather than into the openings  708 ′.  
     [0070] The principles, preferred embodiments, and modes of operation of the present invention have been described in the foregoing description. However, the invention that is intended to be protected is not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. Others may make variations and changes, and equivalents employed, without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such variations, changes and equivalents which fall within the spirit and scope of the present invention as defined in the claims be embraced thereby.