Patent Publication Number: US-10332695-B2

Title: Key switch with noise reduction mechanism

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of application Ser. No. 15/796,473, filed Oct. 27, 2017, which is a continuation of application Ser. No. 15/049,153, filed Feb. 22, 2016. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a key switch, and more particularly to a key switch with noise reduction mechanism. 
     2. Description of the Prior Art 
     Keyboard is an input device for inputting words, characters, and numbers and has been indispensable to the operations of personal computers, consumer electronics, and industrial process equipments. 
     On a typical keyboard, most of the keys have standard size square keycaps, while other keys, such as the Space bar, Enter key, Caps Lock key, and Shift key, have enlarged keycaps. 
     For those keys with enlarged keycaps, support rods are adopted to enhance the structural strength of keycaps so that the enlarged keycaps would not tilt when the user presses the keys at positions other than the center of the keys. However, as support rods are usually designed to be in direct contact with the baseplate and the area of contact between the two components is relatively large, upward and downward movements of keycaps typically cause undesirable noises resulting from collision between the support rod and the baseplate. Consequently, there is a need for a key switch with reduced typing noise and good structural strength sufficient for use on keyboards for frequently operated consumer electronics. 
     SUMMARY OF THE INVENTION 
     The present invention provides a key switch to achieve volume reduction of noises produced during key pressing. 
     An embodiment of the present invention provides a key switch, which includes a baseplate, a circuit layer, a keycap, and a support rod. The baseplate has a hook and a first through hole neighboring to the hook. The circuit layer includes a first sublayer and a second sublayer. The first sublayer is disposed above the baseplate and has a second through hole. The second sublayer is disposed above the first sublayer and has a third through hole; a portion of the second sublayer extends over the second through hole and forms a first resilient portion. The first resilient portion has at least four sides, with at least two sides of the four sides connecting to the second sublayer; and the first resilient portion is neighboring to the hook. The keycap is disposed above the baseplate and can move upward and downward in respect to the baseplate. The support rod has a first portion and a second portion; the first portion movably connects to the keycap, and the second portion engages the hook so that a lower end of the second portion passes through the third through hole and the second through hole and reaches the first through hole; meanwhile, the first resilient portion extends beneath and abuts against the second portion the first resilient portion so that the first resilient portion buffers the collision between the second portion and the baseplate when the keycap moves upward and downward in respect to the baseplate. 
     Another embodiment of the present invention provides a key switch, which includes a baseplate, a circuit layer, a film, a keycap, and a support rod. The baseplate has a hook and a first through hole neighboring to the hook. The circuit layer is disposed above the baseplate and has a second through hole. The film is disposed above the circuit layer and has a third through hole; a portion of the film extends over the second through hole and forms a first resilient portion; the first resilient portion has at least four sides, with at least two sides of the four sides connecting to the film and at least two other sides of the four sides separating from the film; the first resilient portion is neighboring to the hook. The keycap is disposed above the baseplate and can move upward and downward in respect to the baseplate. The support rod has a first portion and a second portion; the first portion movably connects to the keycap, and the second portion engages the hook so that a lower end of the second portion passes through the third through hole and the second through hole and reaches the first through hole; the first resilient portion extends beneath and abuts against the second portion so that the first resilient portion buffers the collision between the second portion and the baseplate when the keycap moves upward and downward in respect to the baseplate. 
     Yet another embodiment of the present invention provides a key switch, which includes a baseplate, a circuit layer, a keycap, and a support rod. The baseplate has a hook and a first through hole neighboring to the hook. The circuit layer is disposed above the baseplate and has a first sublayer, a second sublayer, and a third sublayer. The first sublayer is disposed above the baseplate and has a second through hole and a lower electrode. The second sublayer is disposed above the first sublayer and has a third through hole and an upper electrode; a portion of the second sublayer extends over the second through hole and forms a first resilient portion; the first resilient portion has at least four sides, with at least two sides of the four sides connecting to the second sublayer. The third sublayer is disposed between the first sublayer and the second sublayer and has a fourth through hole. The keycap is disposed above the baseplate and can move upward and downward in respect to the baseplate; the upper electrode and the lower electrode are separated by the second sublayer and are electrically connected when the keycap moves downward. The support rod has a first portion and a second portion; the first portion movably connects to the keycap, and the second portion engages the hook; the first resilient portion extends beneath and abuts against the second portion so that the first resilient portion buffers the collision between the lower surface of the second portion and the baseplate when the keycap moves upward and downward in respect to the baseplate. 
     The key switch according to the embodiments of the present invention achieves volume reduction of noise produced during key pressing by utilizing a resilient portion to support the second portion of the support rod so as to buffer the collision between the baseplate and the second portion of the support rod when the keycap moves upward and downward in respect to the baseplate. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic three-dimensional view of a key switch according to an embodiment of the present invention; 
         FIG. 2  is a schematic exploded view of the key switch of  FIG. 1 ; 
         FIG. 3  is a schematic cross-sectional view of the key switch of  FIG. 1  along line  3 - 3 ′; and 
         FIG. 4  is a schematic cross-sectional view of the key switch of  FIG. 1  along line  4 - 4 ′; 
         FIG. 5A  is a schematic illustration of a second sublayer of the key switch of  FIG. 1  according to an embodiment of the present invention; 
         FIG. 5B  is a schematic illustration of a second sublayer of the key switch of  FIG. 1  according to an embodiment of the present invention; 
         FIG. 6  is a schematic exploded view of a key switch according to another embodiment of the present invention; 
         FIG. 7  is a schematic exploded view of a key switch according to yet another embodiment of the present invention; 
         FIG. 8  is a schematic three-dimensional view of a key switch according to still another embodiment of the present invention; 
         FIG. 9  is a schematic exploded view of the key switch of  FIG. 8 ; 
         FIG. 10  is a schematic cross-sectional view of the key switch of  FIG. 8  along line  10 - 10 ′; 
         FIG. 11  is a schematic exploded view of a key switch according to yet still another embodiment of the present invention; 
         FIG. 12  is a schematic exploded view of a key switch according to yet still another embodiment of the present invention; 
         FIG. 13  is a schematic illustration of a second sublayer of the key switch of  FIG. 12  according to an embodiment of the present invention; 
         FIG. 14  is a schematic exploded view of a key switch according to yet still another embodiment of the present invention; and 
         FIG. 15  is a schematic illustration of a film of the key switch of  FIG. 14  according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to  FIG. 1  and  FIG. 2 , which illustrate a three-dimensional view and an exploded view of a key switch according to an embodiment of the present invention. 
     The key switch  100  of the present embodiment may include a baseplate  110 , a circuit layer  120 , a keycap  130 , and a support rod  140 . The baseplate  100  has two pairs of opposite sides, two opposing hooks  112 , and two first through holes  114 . Each of the hooks  112  stands on the top surface  110   a  of the baseplate  110  and is neighboring to a corresponding first through hole  114 . The baseplate  110  may be, but is not limited to, a metallic baseplate. 
     The keycap  130  is disposed above the baseplate  110  and can move upward and downward in respect to the baseplate  110 . The support rod  140  has a first portion  142  and two second portions  144  connecting to the two opposite ends of the first portion  142 ; in other words, the second portions  144  may be formed by bending and extending the two opposite ends of the first portion  142  toward the same direction. Meanwhile, the first portion  142  is movably connected to the keycap  130 ; that is, the first portion  142  may attach to the keycap  130  and pivot about the attached position. For example, the first portion  142  may be pivotally connected to the bottom surface of the keycap  130  while each of the second portions  144  may slidably engage a chute  112   a  of the corresponding hook  112 . 
     Additionally, the key switch  100  may further include a recovery unit  150  disposed above the top surface  120   a  of the circuit layer  120 . The recovery unit  150  may be made elastic materials, such as silicone or rubber. In other embodiments, the key switch  100  may also include, but is not limited to, an X-shaped structure. Therefore, when keycap  130  of the key switch  100  moves down to a lower position upon reception of an external force, the first portion  142  of the support rod  140  pivots at the bottom surface of the keycap  130 , and the second portion  144  of the support rod  140  engaging the baseplate  110  slides downward. Alternatively, when the external force is removed, the recovery unit  150  elastically recovers, causing the keycap  130  to move upward, the first portion  142  of the support rod  140  to reversely pivot at the bottom surface of the keycap  130 , the second portion  144  of the support rod  140  engaging the baseplate  110  to slide upward, and thus returning the keycap  130  to the default position. 
     The circuit layer  120  includes a first sublayer  122  and a second sublayer  124 . The first sublayer  122  is disposed above the baseplate  110  and has a second through hole  122   a . The second sublayer  124  is disposed above the first sublayer  122  and has a third through hole  124   a . When superimposing the first sublayer  122  and the second sublayer  124 , a portion of the second sublayer  124  extends over the second through hole. The circuit layer  120  may be, but is not limited to, a thin film circuit board; more specifically, the circuit layer  120  may electrically conduct a signal when keycap  130  is being pressed. Additionally, the circuit layer  120  may further include, but is not limited to, a third sublayer  126  disposed between the first sublayer  122  and the second sublayer  124 . The third sublayer  126  may be, but is not limited to, a plastic insulating sheet. 
     Referring now to  FIG. 3 , which illustrates a cross-sectional view of the key switch of  FIG. 1  along line  3 - 3 ′. Together with  FIGS. 1 and 2 ,  FIG. 3  shows that the third sublayer  126  includes an accommodating through hole  127  corresponding to the recovery unit  150  to electrically separate the first sublayer  122  and the second sublayer  124 . When keycap  130  is being pressed, the recovery unit  150  received a downward force, causing the second sublayer  124  to deform, pass through the accommodating through hole  127 , and be in direct contact with the first sublayer  122  and therefore electrically connect to the first sublayer  122 . More specifically, the second sublayer  124  may include an upper electrode  125  disposed below the recovery unit  150 , and the first sublayer  122  may include a lower electrode  123  disposed in correspondence to the upper electrode  125 ; that is, the upper electrode  125  and the lower electrode  123  may be disposed at two opposite sides of the accommodating through hole  127 , so that the contact between the upper electrode  125  and the lower electrode  123  would activate the circuit layer to produce an electrical signal; the present invention is not limited thereto however. Alternatively, when the external force applied to the keycap  130  is removed, the first sublayer  122  and the second sublayer  124  would return to the default positions, resulting in disassociation of the upper electrode  125  with the lower electrode  123 . 
     Referring now to  FIG. 4 , which illustrates a cross-sectional view of the key switch of  FIG. 1  along line  4 - 4 ′. Together with  FIGS. 1 and 2 ,  FIG. 4  shows that when superimposing the first sublayer  122  and the second sublayer  124 , a portion of the second sublayer  124  extends over the second through hole  122   a  and forms a first resilient portion  160 . The first resilient portion  160  includes at least four sides  161 , with at least two of the four sides connecting to the second sublayer  124 , and is neighboring to the hook  112  protruding over the second through hole  122   a . Therefore, when the second portion  144  of the support rod  140  engages the hook  112 , a lower end of the second portion  144  locates within the through hole formed by the first through hole  114 , the second through hole  122   a , and the third through hole  124   a ; and the first resilient portion  160  extends beneath and abuts against the second portion  144 , so that the first resilient portion  160  buffers the collision between the second portion  144  of the support rod  140  and the baseplate  110  when the keycap  130  moves upward and downward in respect to the baseplate  110 , thus reducing noises produced during pressing of the key switch  100  of the present embodiment. 
     Additionally, when the circuit layer  120  further includes the third sublayer  126  that is superimposable with the first sublayer  122  and the second sublayer  124 , a portion of the third sublayer  126  extends over the second through hole  122   a  and forms a second resilient portion  170 . The first resilient portion  160  and the second resilient portion  170  are at least partially overlapped. Consequently, the second resilient portion  170  may deform with the first resilient portion  160  in response to press forces applied onto the keycap  130 , therefore providing sufficient buffer between the second portion  144  of the support rod  140  and the baseplate  110  and reducing noises produced during pressing of the key switch  100 . Moreover, the second resilient portion  170  has a configuration substantially identical to that of the first resilient portion  160 ; that is, the second resilient portion  170  includes at least four sides  171 , and at least two of the four sides  171  connect to the third sublayer  126 . However, it is to be understood that the present invention is not limited thereto. In other embodiments, configuration of the third sublayer  126  may be substantially identical to that of the first sublayer  122 ; that is, space between the second portion  144  of the support rod  140  and the baseplate  110  may be buffered only by the first resilient portion  160  at the second sublayer  124  to accomplish typing noise reduction. 
     Referring now to  FIG. 5A , which specifically illustrates the second sublayer  124  of the key switch  100  of  FIG. 1  according to an embodiment of the present invention. As shown in  FIG. 5A , the first resilient portion  160  at the second sublayer  124  may include a fourth through hole  162  and a rectangular structure  164 . The rectangular structure  164  extends between the third through hole  124   a  and the fourth through hole  162 ; that is, the first resilient portion  160  may be quadrilateral and have a first side  161   a , a second side  161   b , a third side  161   c , and a fourth side  161   d  that are sequentially arranged. Likewise, the four sides  161  illustrated in  FIG. 2  may be further defined as the first side  161   a , the second side  161   b , the third side  161   c , and the fourth side  161   d . The first resilient portion  160  connects to the second sublayer  124  via the first side  161   a  and the neighboring second side  161   b ; meanwhile, the third side  161   c  is neighboring to the third through hole  124   a  and the fourth side  161   d  is neighboring to the fourth through hole  162 . 
     Referring now to  FIG. 5B , which illustrates the second sublayer  124  of the key switch  100  of  FIG. 1  according to another embodiment of the present invention. As shown in  FIG. 5B , the rectangular structure  164  the extends between the third through hole  124   a  and the fourth through hole  162 ; the rectangular structure  164  has two ends  164   a  connecting to the second sublayer  124 . More specifically, the rectangular structure  164  of the present embodiment may be an L-shaped structure, with the two ends  164   a  of the L shape extending toward the first side  161   a  and the second side  161   b  of the first resilient portion  160 , respectively. 
     Referring again to  FIG. 4 , as the rectangular structure  164  of the first resilient portion  160  extends beneath and abuts against the second portion  144  of the support rod  140  when the keycap  130  moves upward and downward in respect to the baseplate  110 , strain required to deform the rectangular structure  164  may be adjustable by simply altering the size, shape, and position of the fourth through hole  162 . In other words, size, shape, and position of the fourth through hole  162  may be adjusted according to the strength of press force applied onto the keycap  130 , so that the rectangular structure  164  would deform under a corresponding press force. Consequently, not only the strength of press force required for a user to activate signal conduction at the circuit layer  120  would not be affected, collision between the second portion  144  of the support rod  140  and the baseplate  110  would be buffered, thus reducing the volume of noise produced during pressing the key switch  100 . 
     Referring now to  FIG. 6 , which illustrates an exploded view of a key switch according to another embodiment of the present invention. It is to be understood that key switch  200  of the present embodiment is substantially identical to key switch  100  illustrated in  FIG. 2 . The main difference is that the key switch  200  further includes a film  180 . The film  180  is disposed above the circuit layer  120  and the recovery unit  150  may be disposed above the film  180 . When superimposing the film  180  and the circuit layer  120 , a portion of the film  180  extends over the second through hole  122   a  and forms a third resilient portion  190 . The first resilient portion  160  and the third resilient portion  190  are at least partially overlapped; for example, configuration of the third resilient portion  190  may be substantially identical to that of the first resilient portion  160 , and thus the film  180  may have a configuration substantially identical to that of the second sublayer  124 ; the present invention is not limited thereto however. The film  180  may be, but is not limited to, made of elastic materials such as polyester (Mylar) or rubber. Therefore, the third resilient portion  190  on the film  180  may deform with the first resilient portion  160  in response to press forces applied onto the keycap  130 , therefore providing sufficient buffer between the second portion  144  of the support rod  140  and the baseplate  110  and reducing noises produced during pressing of the key switch  200 . 
     Likewise, when circuit layer  120  of the present embodiment includes the third sublayer  126  with the second resilient portion  190  disposed thereon, the first resilient portion  160 , the second resilient portion  170 , and the third resilient portion  190  may deform simultaneously in response to press forces applied onto the keycap  130 , therefore providing sufficient buffer between the second portion  144  of the support rod  140  and the baseplate  110  and reducing noises produced during pressing of the key switch  200 . However, the present invention is not limited thereto; in other embodiments, the third sublayer  126  may have a configuration substantially identically to that of the first sublayer  122 , thus having no second resilient portion disposed thereon. 
     Referring now to  FIG. 7 , which illustrates an exploded view of a key switch according to yet another embodiment of the present invention. It is to be understood that key switch  300  of the present embodiment is substantially identical to key switch  100  illustrated in  FIG. 2 . The main difference is that the key switch  300  further includes a film  180 . The film  180  includes a third through hole  182 , and a portion of the film  180  extends over the second through hole  122   a  to form a first resilient portion  184  on the film  180 . In other words, the first resilient portion  184  adopted to reduce the volume of noises produced during pressing the key switch  300  may be disposed above the film  180 . Therefore, the first resilient portion  184  on the film  180  buffers the collision between the second portion  144  of the support rod  140  and the baseplate  110 , so as to reduce noises produced during pressing the key switch  300 . Additionally, configuration of the first resilient portion  184  on the film  180  of the present embodiment may be substantially identical to that of the first resilient portion  160  at the second sublayer  124  as illustrated in  FIG. 5A  or in  FIG. 5B ; the present invention is not limited thereto however. Furthermore, the first resilient portion  184  on the film  180  may further include a fourth through hole  184   a , for reducing the strain required to deform the first resilient portion  184 . That is, size, shape, and position of the fourth through hole  184   a  may be adjusted according to the strength of press force applied onto the keycap  130 , so that the first resilient portion  184  would deform under a corresponding press force. Consequently, not only the strength of press force required for a user to activate signal conduction at the circuit layer  120  would not be affected, collision between the second portion  144  of the support rod  140  and the baseplate  110  would be buffered, thus reducing the volume of noise produced during pressing the key switch  300 . 
     Referring now to  FIG. 8  and  FIG. 9 , which illustrate a three-dimensional view and an exploded view of a key switch according to yet still another embodiment of the present invention. Key switch  400  of the present embodiment is substantially identical to key switch  100  as illustrated in  FIGS. 1 and 2 . The main difference is that the key switch  400  includes two support rods  140  and that each of the two opposing hooks  112  disposed at two opposite sides of the baseplate  110  has two chutes  112   a . The lower end  144   a  of the second portion  144  of the support rod  140  bends and engages the chute  112   a  of the hook  112 , and each of the hooks  112  may simultaneously engage the lower ends  144   a  of two second portions  144  on the same side; the present invention is not limited thereto however. Therein, the lower end  144   a  extends substantially horizontally. A long axis  144   b  (indicated by a chain line in  FIG. 9 ) of each of the two lower ends  144   a  is substantially perpendicular to a long axis  260   a  (indicated by a chain line in  FIG. 9 ) of the first resilient portion  260 . The circuit layer  120  has a through hole structure that is formed by the through holes  122   a ,  124   a  and  126   b  and passes through the sublayers  122 ,  124  and  126 . Additionally, configuration of the first resilient portion  260  at the second sublayer  124  of the circuit layer  120  is different from that of the first resilient portion  160  in  FIG. 2 . More specifically, the first resilient portion  260  of the present embodiment is a quadrilateral sheet having a first side  261   a , a second side  261   b , a third side  261   c , and a fourth side  261   d  that are sequentially arranged. The first resilient portion  260  connects to the second sublayer  124  via the first side  261   a  and the third side  261   c  opposite to the first side  261   a , and the second side  261   b  is neighboring to the third through hole  124   a . Further, the first resilient portion  260  may include a fourth through hole  262  and a linear structure  264 . The linear structure  264  has two ends  264   a  and extends between the third through hole  124   a  and the fourth through hole  262  at the second sublayer  124 . Meanwhile, the two ends  264   a  of the linear structure  264  extend toward the first side  261   a  and the third side  261   c , respectively; that is, the first resilient portion  260  is a U-shaped sheet in the present embodiment. The present invention is not limited thereto however. 
     Referring now to  FIG. 10 , which illustrates a cross-sectional view of the key switch of  FIG. 8  along line  10 - 10 ′. As shown in  FIGS. 8 through 10 , if the lower end  144   a  of the second portion  144  of the support rod  140  extends horizontally, the lower end  144   a  of the second portion  144  engages the hooks by extending on top of the through hole formed together by the first through hole  114 , the second through hole  122   a , and the third through hole  124   a . Alternatively, if the lower end  144   a  of the second portion  144  bends, the lower end  144   a  of the second portion  144  passes through the through hole formed together by the first through hole  114 , the second through hole  122   a , and the third through hole  124   a ; and the linear structure  264  of the first resilient portion  260  extends beneath and abuts against the second portion  144  toward the first side  261   a  and the third side  261   c . Consequently, the first resilient portion  260  would buffer the collision between the second portion  144  of the support rod  140  and the baseplate  110  when the keycap  130  moves upward and downward in respect to the baseplate, therefore reducing the noises produced by pressing the key switch  400 . 
     Referring again to  FIG. 9 . It is apparent that the circuit layer  120  of the present embodiment may further include a third sublayer  126  disposed between the first sublayer  122  and the second sublayer  124 . A portion of the third sublayer  126  extends over the second through hole  122   a  and forms a second resilient portion  270 . Configuration of the second resilient portion  270  is substantially identical to that of the first resilient portion  260 ; the present invention is not limited thereto however. In other embodiments, the third sublayer  126  may not include a second resilient portion; that is, the third sublayer  126  has a configuration substantially identical to that of the first sublayer  122 . Furthermore, teachings of the embodiment illustrated in  FIG. 6  have made it apparent that the key switch may further include a film having a third resilient portion and disposed above the circuit layer. Configuration of the third resilient portion may be, but is not limited to, substantially identical to that of the first resilient portion. In other embodiments, the film may be configured to substantially resemble the first sublayer  122 ; that is, the film may have no third resilient portion disposed thereon. 
     Referring now to  FIG. 11 , which illustrates an exploded view of a key switch according to yet still another embodiment of the present invention. Key switch  500  as shown in  FIG. 11  is substantially identical to the key switch  400  illustrated in  FIG. 9 . The main difference is that the key switch  500  of the present embodiment includes a film  280  having a third through hole  282 . A portion of the film  280  extends over the second through hole  122   a  and forms a resilient portion  284 . The film  280  buffers the collision between the second portion  144  of the support rod  140  and the baseplate  110 , so as to reduce the noises produced during pressing of the key switch  500 . Additionally, configuration of the first resilient portion  284  of the film  280  may be substantially identical to the first resilient portion  260  of the second sublayer  124  as illustrated in  FIG. 9 . Consequently, as the first resilient portion  284  extends beneath and abuts against the second portion  144  of the support rod  140  when the keycap  140  moves upward and downward in respect to the baseplate  110 , the fourth through hole  284   a  reduces the strain required to deform the first resilient portion  284 . That is, size, shape, and position of the fourth through hole  284   a  may be adjusted according to the strength of press force applied onto the keycap  130 , so that the first resilient portion  284  would deform under a corresponding press force. In this way, not only the strength of press force required for a user to activate signal conduction at the circuit layer  120  would not be affected, collision between the second portion  144  of the support rod  140  and the baseplate  110  would be buffered, thus reducing the volume of noise produced during pressing the key switch  500 . 
     Referring now to  FIG. 12  and  FIG. 13 , which illustrate an exploded view of a key switch and a plain view of the second sublayer of the key switch according to yet still another embodiment of the present invention. Key switch  600  as shown in  FIGS. 12 and 13  is substantially identical to the key switch  100  illustrated in  FIGS. 1 and 2 . The main difference lies on the configuration of the circuit layer  120 . 
     In the present embodiment, the second sublayer  124  of the circuit layer  120  of the key switch  600  is an upper electrode layer, and the lower surface of the second sublayer  124  typically is disposed with an upper electrode switch. The second sublayer  124  includes a third through hole  124   a , a fourth through hole  162 , a fifth through hole  166 , a rectangular structure  164 , and a second bridging extension  168 . The rectangular structure  164  includes a first side  161   a , a second side  161   b , a third side  161   c , and a fourth side  161   d  that are sequentially arranged; the first side  161   a  is opposite and not neighboring to the third side  161   c ; the second side  161   b  is neighboring to the fourth through hole  162 , and the fourth side  161   d  is neighboring to the third through hole  124   a . The second bridging extension  168  is further divided into a first extension  168   a  extending along the y-axis and a second extension  168   b  extending along the x-axis. The first extension  168   a  separates at least the fifth through hole  166  and the fourth through hole  162 ; the second extension  168   b  separates at least the fifth through hole  166  and the third through hole  124   a ; and the first extension  168   a  connects to the second extension  168   b . The rectangular structure  164  connects to the edge of the keycap  130  neighboring to the second sublayer  124  via the first side  161   a , and to the first extension  168   a  via the third side  161   c , so that the rectangular structure  164  separates the third through hole  124   a  and the fourth through hole  162  and two ends (that is, the first side  161   a  and the third side  161   c ) of the rectangular structure  164  are structurally supported, therefore providing stronger elasticity for noise reduction. In the present embodiment, while the second bridging extension  168  is typically of an L contour, the exact shape of the second bridging extension  168  is not limited thereto; all possible shapes of the second bridging extension  168  that (a) have disconnection between the second side  161   b  and the fourth side  161   d , with the second side  161   b  and the fourth side  161   d  connecting to any of the through holes; and (b) connects to the third side  161   c  of the rectangular structure  164  are feasible for the present invention. 
     On the other hand, the first sublayer  122  of the circuit layer  120  of the present embodiment is a lower electrode layer, typically disposed in correspond to the upper electrode switch. The upper surface of the first sublayer  122  is disposed with a lower electrode switch for selectively activate electrical conduction. The first sublayer  122  includes a second through hole  122   a  and a sixth through hole  122   b , and a first bridging extension  121 ; the first bridging extension  121  is further divided into a third extension  122   c  and a fourth extension  122   d . When superimposing the first sublayer  122  with the second sublayer  124 , elements extending over the second through hole  122   a  include the rectangular structure  164 , at least partial of the third through hole  124   a , and at least partial of the fourth through hole  162 , such that the rectangular structure  164  extends over the second through hole  122   a ; further, the third extension  122   c  and the fourth extension  122   d  superimpose with and is disposed under the first extension  168   a  and the second extension  168   b , such as the first bridging extension  121  structurally supports the second bridging extension  168 ; the present invention is not limited thereto however. The third extension  122   c  and the fourth extension  122   d  separates the sixth through hole  122   b  from the second through hole  122   a ; when superimposing the first sublayer  122  with the second sublayer  124 , the sixth through hole  122   b  superimposes with the fifth through hole  166 ; the present invention is not limited thereto however. 
     In the present embodiment, the third sublayer  126  further included in the circuit layer  120  is a spacer layer, typically disposed in correspond to the upper and lower electrode switches. The third sublayer  125  is disposed with an accommodating through hole  127  for allowing the upper electrode to deform and pass through the accommodating through hole  127  so as to contact the lower electrode switch for electrical conduction when the upper electrode switch is pressed by the user. The third sublayer  126  superimposes with the first sublayer  122  and the second sublayer  124 ; as shown in  FIG. 12 , configuration of the third sublayer  126  may be identical to that of the second sublayer  124  except for the accommodating through hole  127  at the third sublayer  126 . In other words, the third sublayer  126  may also include a rectangular structure; together with the rectangular structure  164  at the second sublayer  124 , the two rectangular structures support the support rod  140  for noise reduction; the present invention is not limited thereto however. In other embodiments, configuration of the third sublayer  126  may be identical to that of the first sublayer  122  except for the accommodating through hole  127  at the third sublayer  126 . In other words, the third sublayer  126  may also be disposed without a rectangular structure; the through hole  126   a  at the third sublayer  125  superimposes with and covers the rectangular structure  164 , at least partial of the third through hole  124   a , and at least partial of the fourth through hole  162 ; such that the entire circuit layer  120  uses only the rectangular structure  164  at the second sublayer  124  to support the support rod  140  for noise reduction. 
     Referring now to  FIG. 14  and  FIG. 15 , which illustrate an exploded view of a key switch and a plain view of the film of the key switch according to yet still another embodiment of the present invention. It is to be understood that key switch  700  of the present embodiment as shown in  FIGS. 14 and 15  is substantially identical to the key switch  300  illustrated in  FIG. 7 ; that is, a film  180  is disposed above the circuit layer  120 , and the recovery unit  150  is disposed above the film  180  but not the circuit layer  120 ; however, the film  180  in  FIG. 14  has a configuration different from that of film in  FIG. 7 . Instead, configuration of the film  180  in  FIG. 14  is identical to that of the second sublayer  124  of the key switch  600  shown in  FIG. 12 ; that is, the film  180  includes a seventh through hole  185   a , an eighth through hole  185   b , a ninth through hole  185   c , a rectangular structure  187 , and a third bridging extension  189 . The rectangular structure  187  has at least a first side  187   a , a second side  187   b , a third side  187   c , and a fourth side  187   d  that are sequentially arranged. The first side  187   a  is opposite to and disconnect with the third side  187   b ; the second side  187   b  is neighboring to the eighth through hole  185   b , and the fourth side  187   d  is neighboring to the seventh through hole  185   a . The rectangular structure  187  connects to the edge of the keycap  130  neighboring to the film  180  via the first side  187   a , and to the third bridging extension  189  via the third side  187   c , so that the rectangular structure  187  separates the eighth through hole  185   b  and the seventh through hole  185   a  and two ends (that is, the first side  187   a  and the third side  187   c ) of the rectangular structure  187  are structurally supported; therefore, configuration of the film  180  of the present embodiment may be identical, but not limited, to the second sublayer  124  illustrated in  FIG. 13 . On the other hand, configuration of the circuit layer  120  of the present embodiment may be identical to the circuit layer  120  of the key switch  600  illustrated in  FIG. 12 ; that is, the circuit layer  120  may (a) include a rectangular structure  164  only at the second sublayer  124 , but not at any other sublayers; or (b) include two rectangular structures, with one disposed at the second sublayer  124  and the other at the third sublayer  126 , and only the first sublayer  122  is disposed without a rectangular structure; the present invention is not limited thereto however. 
     According to the aforementioned embodiments of the present invention, the key switch of the present invention provides the following advantages. The key switch utilized a resilient portion to support the second portion of the support rod so as to buffer the collision between the second portion and the baseplate when the keycap moves upward and downward in respect to the baseplate. Moreover, the first resilient portion may be disposed with one or more through holes for reducing the strain required to deform the first resilient portion, such that the first resilient portion would deform under a corresponding press force. Consequently, a user of the key switch may easily activate electrical conduction at the circuit layer by pressing the keycap with a proper press force, and noise produced during key pressing may be reduced as well. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.