Abstract:
A keyswitch assembly includes a movable keycap having a space provided in a bottom of the keycap; a metal support plate having an opening, the metal including a cantilever bridge; a switch located under the opening of the metal support plate; a magnet disposed within the space of the keycap; wherein as the keycap is undepressed, the keycap is in an initial state and the keyswitch assembly is OFF, and the magnet draws in the cantilever bridge, and as the keycap is depressed downward, the magnet is forced to depart from the cantilever bridge and actuates the switch making the keyswitch assembly to turn ON. As the forced is released, the magnetic force between the cantilever bridge and the magnet forces the keycap to return its initial state.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This utility application claims priority to Taiwan application serial number 100210415, filed on Jun. 9, 2011, and 100214365, filed on Aug. 4, 2011, that are incorporated herein by reference. 
       BACKGROUND OF THE DISCLOSURE 
       [0002]    1. Field of the Disclosure 
         [0003]    The invention relates to a keyswitch assembly and a keyboard, and more particularly, to a keyswitch assembly utilizing the magnetic attraction force as restoration driving force for the keycap. 
         [0004]    2. Brief Description of the Related Art 
         [0005]    Other than the mobile devices with touch panel input apparatus, to many electronic devices the keyboard still is an indispensable apparatus. But due to the need for ultra thin notebook computers, keyboard on the ultra thin notebook computers needs to be as thin as possible. 
         [0006]    The conventional keyswitch assembly typically has an elastic element, such as the rubber dome, which provides a driving force resuming the keycap to its initial state as an applied force on keyswitch is released. However, the conventional elastic element has a minimum height for operation which requires a height for the keyswitch assembly to accommodate the elastic element. In other words, the size of conventional keyswitch assembly can not be reduced further due to the existence of the elastic element. 
         [0007]    The keyswitch having magnetic elements has been used in the production of keyswitch assembly, and the related technologies can be found in U.S. Pat. No. 4,453,148. 
         [0008]    One of the objectives of the invention is the reduction of overall height of keyswitch and the keyboard. 
         [0009]    The technical issue to be tackled is achieved by providing a keyswitch assembly employing magnetic attraction force as driving force for the keycap to restore to its initial state by the invention. 
       SUMMARY OF THE DISCLOSURE 
       [0010]    According to a preferred embodiment, the keyswitch assembly includes a movable keycap, a metal support plate, a switch and a magnet. The movable keycap has a bottom providing a space. The metal support plate has an opening and includes a cantilever bridge. The switch is located beneath the opening of support plate. The magnet is disposed within the space of keycap. As the keycap is undepressed, the keycap is in an initial state and the keyswitch assembly is in OFF state, and the magnet attracts to contact the cantilever bridge. As the keycap moves downward by a force, the magnet actuates the switch making the keyswitch assembly in ON state. As the force is released the keycap resumes to the initial state, due to the magnetic attraction force between the magnet and the cantilever bridge. 
         [0011]    In one embodiment, the keycap includes a pivotal for connecting to the metal support plate pivotally. 
         [0012]    According to a second preferred embodiment, the keyswitch assembly includes a movable keycap, a metal support plate, a switch and a magnet. The movable keycap has a space. The metal support plate has an opening and includes a bridge pillar and a bridge floor. The switch is located beneath the opening of the support plate . The magnet is disposed within the space of keycap. As the keycap is undepressed, the keycap is in an initial state and the keyswitch assembly is in OFF state, and the magnet attracts to contact the bridge floor. As the keycap moves downward by a force, the magnet actuates the membrane switch making the keyswitch assembly in ON state. As the force is released, the keycap resumes to the initial state due to the magnetic attraction force between the magnet and the bridge floor. The switch may be a membrane switch. 
         [0013]    According to a third preferred embodiment, the keyswitch assembly includes a movable keycap, a metal support plate, a switch and a magnet. The movable keycap has a bottom extending to form a hook leg and the hook leg has a leg plane. The metal support plate includes a cantilever bridge. The switch is located beneath the keycap. The magnet is disposed on the leg plane. As the keycap is undepressed, the keycap is in an initial state and the keyswitch assembly is in OFF state, and the magnet attracts to contact the cantilever bridge. As the keycap moves downward by a force, the magnet escapes from the cantilever bridge. As the force is released, the keycap resumes to the initial state due to the magnetic attraction force between the magnet and the cantilever bridge. As the keycap moves downward by a force, the hook leg actuates the switch. 
         [0014]    In one embodiment, keyswitch assembly further comprises a scissors-type supporting element respectively connected to the keycap and the metal support plate, wherein the scissors-type supporting element further includes an actuator, and as the keycap moves downward by a force, the actuator actuates the switch. 
         [0015]    In one embodiment, an actuator is provided at the bottom of keycap, and as the keycap moves downward by a force, the actuator actuates the switch. 
         [0016]    According to the fourth preferred embodiment, the keyswitch assembly includes a movable keycap, a metal support plate, and a switch. The movable keycap has a bottom extending to form a hook leg, the hook leg has a leg plane and the leg plane is embedded with a metal plate. The metal support plate includes a cantilever bridge having a bottom providing a magnet which corresponds to the metal plate. The switch is located beneath the keycap. As the keycap is undepressed, the keycap is in an initial state and the keyswitch assembly is in OFF state, and the magnet attracts to contact the metal plate. As the keycap moves downward by a force, the magnet escapes from the metal plate. As the force is released, the keycap resumes to the initial state due to magnetic attraction force between the magnet and the metal plate. As the keycap moves downward by a force, the hook leg actuates the switch. 
         [0017]    The accompanying drawings, incorporated as a part of this specification, are used for further understandings of the preferred embodiments of the invention and can not be used to limit the protected scope of the invention that are described in the attached claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1A  illustrate a keyswitch assembly in accordance with an embodiment of the present invention in explosive form. 
           [0019]      FIG. 1B  illustrates the keyswitch assembly of  FIG. 1A  in assembly form (while switch is OFF). 
           [0020]      FIG. 1C  illustrates the keyswitch assembly of  FIG. 1A  in assembly form (while switch is ON). 
           [0021]      FIG. 2A  illustrates a keyswitch assembly in accordance with a second embodiment of the present invention in explosive form. 
           [0022]      FIG. 2B  illustrates the keyswitch assembly of  FIG. 2A  in assembly form (while switch is OFF). 
           [0023]      FIG. 2C  illustrates the keyswitch assembly of  FIG. 2A  in assembly form (while switch is ON). 
           [0024]      FIG. 3A  illustrates a third preferred embodiment. 
           [0025]      FIG. 3B  illustrates a fourth preferred embodiment. 
           [0026]      FIG. 3C  illustrates a fifth preferred embodiment. 
           [0027]      FIG. 4A  illustrates another (sixth) preferred embodiment. 
           [0028]      FIG. 4B  illustrates still another (seventh) preferred embodiment. 
           [0029]      FIG. 4C  illustrates still preferred (eighth) embodiment. 
       
    
    
       [0030]    While preferred embodiments are depicted in the drawings, those embodiments are illustrative and are not exhaustive, and many other equivalent embodiments may be envisioned and practiced based on the present disclosure by persons skilled in the arts. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0031]    The present invention now will be described more fully herein with reference to the accompanied figures, in which embodiments of the invention are shown. This invention may, however, be embodied in many alternate forms and should not be construed as limited to the embodiments set forth herein. 
         [0032]    Accordingly, while the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the claims. Like numbers refer to like elements throughout the description of the figures. 
         [0033]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising” used in this specification do not preclude the presence or addition of one or more other selectivity features, steps, operations, elements, components, and/or groups thereof. And the term “and/or” includes any and all combinations of one or more of the associated listed items. 
         [0034]    Unless otherwise defined, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms defined in commonly used dictionaries will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
         [0035]    Referring to  FIG. 1A , a preferred embodiment of the keyswitch assembly  10  shown includes a movable keycap  100 , a metal support plate  104 , a switch  109 , and a magnet  107 . The bottom of movable keycap  100  has a space  102 . The metal support plate  104  has an opening  106  and includes a cantilever bridge  108 . The switch  109  is located beneath the opening  106  of support plate  104 . The magnet  107  is disposed within the space  102  of keycap  100 . As the keycap  100  is undepressed, the keycap  100  is in an initial state shown in  FIG. 1B , and the keyswitch assembly  10  is in OFF state, the magnet  107  attracts to contact the cantilever bridge  108 . As the keycap  100  moves downward by a force, the magnet  107  actuates the switch  109  making the keyswitch assembly  10  in ON state. As the applied force is released, because of the magnetic attraction force between the magnet  107  and the cantilever bridge  108 , the keycap  100  resumes to the initial state. The keycap  100  has a pivotal  100   a  for connecting pivotally to the metal support plate  104 . The switch  109  may be a printed circuit board membrane switch of single layer, dual layers or three layers. 
         [0036]      FIG. 1B  shows the keyswitch assembly of  FIG. 1A  in assembly form (while switch  109  is OFF). Since the attraction force between the magnet  107  and the cantilever bridge  108 , the keycap  100  naturally moves upwardly to an upper dead point at which the switch  109  is OFF.  FIG. 1C  shows the keyswitch assembly of  FIG. 1A  in assembly form (while switch  109  is ON) when an external force is applied on the keycap  100 . This external force must to confront the magnetic attraction force between the magnet  107  and the cantilever bridge  108  in order to move the keycap  100  downward to a lower dead point. As the lower dead point is reached, the switch  109  is turned ON by the magnet  107 . Afterwards as the applied force disappears, the keyswitch assembly  10  will transit from state of  FIG. 1C  to that of  FIG. 1B . 
         [0037]    In another preferred embodiment shown in  FIG. 2A , a keyswitch assembly  20  includes a movable keycap  200  having a space  202 , a metal support plate  204  having an opening, a switch  209  and a magnet  207 . The metal support plate  204  includes a bridge pillar  208   a  and a bridge floor  208   b.  The switch  209  is located beneath the opening of support plate  204 . The magnet  207  is disposed within the space  202  of keycap  200 . As the keycap  200  is undepressed, the keycap  200  is in an initial state, as shown in  FIG. 2B , and the keyswitch assembly  20  is in OFF state, and the magnet  207  attracts to contact the bridge floor  208   b.  As the keycap  200  moves downward due to a force, the magnet  207  actuates the switch  209  making the keyswitch assembly  20  in ON state. As the force is released, the keycap  200  moves upward resuming to the initial state due to the magnetic attraction force between the magnet  207  and the bridge floor  208   b.    
         [0038]      FIG. 2B  shows the keyswitch assembly of  FIG. 2A  in assembly form (while the switch  209  is OFF). Due to the attraction force between the magnet  207  and the bridge floor  208   a,  the keycap  200  naturally moves upward to an upper dead point at which the switch  209  is in OFF state.  FIG. 2C  shows the keyswitch assembly of  FIG. 2A  in assembly form (while the switch  209  is ON) in which an external force is applied on the keycap  200 . This external force has to resist the magnetic attraction force between the magnet  207  and the bridge floor  208   a  in order to move the keycap  200  downward to a lower dead point. As the lower dead point is reached, the switch  209  is activated to ON state by the magnet  207 . Afterwards as the applied force disappears, the state of the keyswitch assembly  20  changes from state of  FIG. 2C  to that of  FIG. 2B . 
         [0039]    Furthermore, the distance between two bridge pillars  208   a  may be about identical to the width of the magnet  207  to restrain the lateral displacement of the magnet  207  during its vertical movement. The switch  209  may be a membrane switch. 
         [0040]    While employing the above described keyswitch assembly  10 , a preferred embodiment of the invention is a keyboard which includes at least a keyswitch assembly  10 . 
         [0041]    As shown in  FIG. 3A , another preferred embodiment of the keyswitch assembly  30  includes a movable keycap  301 , a metal support plate  303 , a switch  319  located beneath the keycap  301  and a magnet  311  disposed on a leg plane. The movable keycap  301  has a bottom extending to form a hook leg  305  which has a leg plane. The metal support plate  303  includes a cantilever bridge  302 . As the keycap  301  is undepressed, the keycap  301  is in an initial state and the keyswitch assembly  30  is in OFF state, and the magnet  311  attracts to contact the cantilever bridge  302 . As the keycap  301  moves downward by a force, the magnet  311  escapes from the cantilever bridge  302 . As the force is released, the magnetic attraction force between the magnet  311  and the cantilever bridge  302  forces the keycap  301  to resume to the initial state. The label  315  indicates a conventional scissors-type supporting element which is respectively connected to the keycap  301  and the metal support plate  303 . The element label  309  indicates a conventional membrane disposed on the circuit membrane  307  for protecting the circuit membrane  307 . According to a preferred embodiment, the membrane  309  may be a Polyester membrane (Mylar). As the keycap  301  moves downward by a force, the hook leg  305  actuates the switch  319 . 
         [0042]      FIG. 3B  discloses another preferred embodiment which has some parts identical to those shown in  FIG. 3A . The difference between this embodiment and that of  FIG. 3A  resides on that the scissors-type supporting element  315  further has an actuator  317  which actuates the switch  319  as the keycap  301  moves downward by a force. 
         [0043]      FIG. 3C  discloses still another preferred embodiment which has some parts identical to those shown in  FIG. 3A . The difference between this embodiment and that of  FIG. 3A  resides on that the downside of keycap  301  has an actuator  317  to actuate the switch  319  as the keycap  301  moves downward by a force. 
         [0044]    As indicated in  FIG. 4A , in accordance with another preferred embodiment, the keyswitch assembly  40  includes a movable keycap  401 , a metal support plate  403  and a switch  429 . The movable keycap  401  has a bottom extending to form a hook leg  405 . The hook leg  405  has a leg plane embedded with a metal plate  422 . The metal support plate  403  includes a cantilever bridge  402  having a bottom which provides a magnet  411  corresponding to the metal plate  422 . The switch  429  is located beneath the keycap  401 . As the keycap  401  is undepressed, the keycap  401  is in an initial state, the keyswitch assembly  40  is in OFF state and the magnet  411  adheres the metal plate  422 . As the keycap  401  moves downward by a force, the magnet  411  escapes from the metal plate  422 . As the force is released, the magnetic attraction force between the magnet  411  and the metal plate  422  forces the keycap  401  to resume to its initial state. The label  425  represents a traditional scissors-type supporting element respectively connected to the keycap and the metal support plate. The label  209  represents a conventional membrane disposed on the circuit membrane  407  for protecting the circuit membrane  407 . According to a preferred embodiment, the membrane  409  might be a Polyester membrane. As the keycap  401  moves downward by a force, the hook leg  405  actuates the switch  429 . 
         [0045]    Alternatively,  FIG. 4B  discloses another preferred embodiment which has parts identical to those shown in  FIG. 4A . The difference between this embodiment and that of  FIG. 4A  resides on that the scissors-type supporting element  425  further has an actuator  417  which actuates the switch  429  as the keycap  401  moves downward by a force. 
         [0046]      FIG. 4C  discloses still another preferred embodiment which has parts identical to those shown in  FIG. 4A . The difference between this embodiment and that of  FIG. 4A  resides on that the downside of keycap  401  has an actuator  417  actuating the switch  429  as the keycap  401  moves downward by a force. 
         [0047]    Unless otherwise stated, all measurements, values, ratings, positions, magnitudes, sizes, and other specifications that are set forth in this specification, including in the claims that follow, are approximate, not exact. They are intended to have a reasonable range that is consistent with the functions to which they relate and with what is customary in the art to which they pertain. Furthermore, unless stated otherwise, the numerical ranges provided are intended to be inclusive of the stated lower and upper values. Moreover, unless stated otherwise, all material selections and numerical values are representative of preferred embodiments and other ranges and/or materials may be used. 
         [0048]    The scope of protection is limited solely by the claims, and such scope is intended and should be interpreted to be as broad as is consistent with the ordinary meaning of the language that is used in the claims when interpreted in light of this specification and the prosecution history that follows, and to encompass all structural and functional equivalents thereof.