Patent Publication Number: US-6713692-B2

Title: Switch mechanism, multidirectional operation switch, and multidirectional operation unit

Description:
FIELD OF THE INVENTION 
     The present invention relates to switch mechanisms, and multidirectional operation switches and multidirectional operation units employing switch mechanisms. These are mainly used for input panels of mobile communications equipment such as mobile phones and pagers, and small and multifunctional electronic apparatuses such as remote controls, audio equipment, games machines, car navigation systems, and digital cameras. 
     BACKGROUND OF THE INVENTION 
     A multidirectional operation switch employing a conventional switch mechanism is described next with reference to FIGS. 10 to  13 . 
     FIG. 10 is a front section view of a conventional multidirectional operation switch. 
     FIG. 11 is an exploded perspective of the same switch. In the multidirectional operation switch in FIGS. 10 and 11, box case  31  made of insulating resin has a cavity at its center. The open top of this cavity is covered with cover  32 , typically made of a metal sheet. 
     FIG. 12 is a plan view of box case  31 . 
     As shown in FIG. 12, common fixed contact  53  and eight inner fixed contacts  33  to  40  are fixed on the bottom face of the cavity of box case  31 , typically by insert molding. 
     The rim of dome-shaped flexible contact  41  made of a thin resilient metal sheet is placed on common fixed contact  53 . All eight inner fixed contacts  33  to  40  are disposed inside common fixed contact  53  on a circumference centering on the center of box case  31  at equal intervals. 
     These fixed contacts  53  and  33  to  40  are electrically coupled to lead-out terminals  63  and  43  to  50  disposed on the outer face of box case  31 . 
     The above common fixed contact  53  is a contact used commonly for electrical coupling with other inner fixed contacts  33  to  40  (hereafter referred to as a common contact). A lead-out terminal electrically coupled to fixed contact  53  is called common terminal  63 . 
     The cavity of box case  31  is octagonal when seen from the top, and its inner wall has eight corners  31 A. 
     Operating member  42  has shaft  42 B and octagonal flange  42 A at the bottom of shaft  42 B. Flange  42  is made integrally with shaft  42 B. Operating member  42  is placed such that shaft  42 B protrudes upward from through hole  32 A at the center of cover  32 , and flange  42 A is housed inside the cavity of box case  31 . Operating member  42  is thus placed inside box case  31 , allowing a tilting operation, but restricting the rotation by inner wall corners  31 A. 
     On the bottom face of flange  42 A of operating member  42 , eight pushing elements  42 D, in total, are provided at positions corresponding to inner fixed contacts  33  to  40  on the bottom face of box case  31 . 
     Dome-shaped flexible contact  41  is positioned by a circular bottom area formed by the inner wall of box case  31  such that its center and the center of operating member  42  match, and placed on common contact  53 . 
     Pushing element  42 D contacts the top face of this dome-shaped flexible contact  41 . This makes the top face of flange  42 A of operating member  42  resiliently contact the bottom face of cover  32  so that operating member  42  is maintained in a vertical neutral position. 
     Next, the operation of the conventional multidirectional operation switch as configured above is described. 
     First, in the normal state, as shown in FIG. 10, connection between any pair of the contacts is in the OFF state 
     FIG. 13 is a front sectional view of operating member  42  during tilting operation. 
     Key  52  is mounted on top end  42 C of shaft  42 B of operating member  42 . When the left top face of key  52  is pressed, as shown by arrow  212  in FIG. 13, operating member  42  tilts about a fulcrum at the right top face of flange  42 A. 
     Pushing element  42 D on the bottom face corresponding to the tilting direction of operating member  42  then pushes dome-shaped flexible contact  41  and partially inverts dome-shaped flexible contact  41 . Then, dome-shaped flexible contact  41  provides tactile ‘click’ and contacts inner fixed contact  34  at the left bottom of box case  31  to turn ON between common contact  53  and inner fixed common contacts  34 . Here, only lead-out common terminal  63  and terminal  44  are electrically coupled. 
     When the pushing force applied to key  52  is released, pushing element  42 D on the bottom face of operating member  42  is pushed back due to the resilience of dome-shaped flexible contact  41 , and operating member  42  returns to the vertical neutral position. 
     In the same way, common terminal  63  and one of the lead-out terminals  43  to  50  corresponding to each pushing position are electrically coupled when a different part of key  52  is pushed. 
     The above multidirectional operation switch with the conventional switch mechanism has terminals  43  and  50  to  63  corresponding respectively to inner fixed contacts  33  to  40  and common contact  53 . Accordingly, the large numbers of terminals hinders downsizing of such multidirectional operation switches. 
     SUMMARY OF THE INVENTION 
     The present invention aims to offer a smaller switch mechanism with fewer terminals, and a multidirectional operation switch and multidirectional operation unit using this switch mechanism. 
     The switch mechanism of the present invention includes a flexible contact and multiple fixed contacts. The multiple fixed contacts are disposed such as to face the flexible contact, and include i) multiple first common contacts used commonly for electrical coupling; ii) multiple second common contacts used commonly for electrical coupling; and iii) multiple independent contacts which are electrically independent. 
     The multiple fixed contacts are disposed such that they are aligned clockwise or counterclockwise repeatedly in a group in the sequence of: first common contact, independent contact, second common contact, and independent contact. In fixed contacts, two adjacent contacts are electrically coupled when the flexible contact touches the two adjacent fixed contacts. 
     Since the multiple fixed contacts are disposed in the sequence as described above, the first common contacts or second common contacts and the independent contact adjacent to it are electrically coupled. 
     In the multidirectional operation switch of the present invention, the multiple fixed contacts are disposed on the inner bottom of the box case made of insulating resin which has an open top. 
     In addition, a dome-shaped flexible contact made of a thin resilient metal sheet is disposed inside the box case such as to cover the multiple fixed contacts. 
     A cover with a through hole covers the opening of the box case. 
     An operating member is configured with a shaft, flange, and pushing element which are integrally molded. 
     The shaft protrudes upward from the through hole. The flange is formed at the bottom end of the shaft, and its periphery is tiltably supported by an inner wall of the cavity of the case. The pushing element is disposed on the bottom face of the flange in a position respectively corresponding to the intermediate position between adjacent fixed contacts so as to contact the dome-shaped flexible contact. 
     The multiple fixed contacts include i) multiple first common contacts used commonly for electrical coupling; ii) multiple second common contacts used commonly for electrical coupling; and iii) multiple independent contacts which are electrically independent These multiple fixed contacts are disposed such that they are aligned clockwise or counterclockwise repeatedly in a group in the sequence of: one first common contact, one independent contact, one second common contact, and another one independent contact. 
     The dome-shaped flexible contact is pressed by the pushing element and contacts two adjacent fixed contacts. This makes the two adjacent fixed contacts electrically coupled. More specifically, the first common contact or second common contact and the independent contact adjacent to it are electrically coupled. 
     In the multidirectional operation unit of the present invention, the multiple fixed contacts are disposed on a wiring board facing the flexible contact. The multiple fixed contacts include i) multiple first common contacts used commonly for electrical coupling; ii) multiple second common contacts used commonly for electrical coupling; and iii) multiple independent contacts which are electrically independent. 
     These multiple fixed contacts are disposed such that they are aligned clockwise or counterclockwise repeatedly in a group in the sequence of: one first common contact, one independent contact, one second common contact, and another one independent contact. In these fixed contacts, adjacent two fixed contacts, i.e., the first common contact or second common contact and the independent contact adjacent to it, are electrically coupled when the flexible contact touches these two adjacent fixed contacts. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front section view of a multidirectional operation switch in accordance with a first exemplary embodiment which has a switch mechanism of the present invention. 
     FIG. 2 is an exploded perspective of the multidirectional operation switch in accordance with the first exemplary embodiment of the present invention. 
     FIG. 3 is a plan view of a box case of the multidirectional operation switch in accordance with the first exemplary embodiment of the present invention. 
     FIG. 4 is a front section view illustrating the tilting state of the multidirectional operation switch in accordance with the first exemplary embodiment of the present invention. 
     FIG. 5 is a perspective, seen from the bottom, of an operating element in another configuration in the multidirectional operation switch in accordance with the first exemplary embodiment of the present invention. 
     FIG. 6 is an exploded perspective of a multidirectional operation unit in accordance with a second exemplary embodiment of the present invention which has the switch mechanism of the present invention. 
     FIG. 7 is a top view of the multidirectional operation unit in accordance with the second exemplary embodiment of the present invention. 
     FIG. 8 is a section view taken along Line  8 — 8  in FIG.  7 . 
     FIG. 9 is a perspective, seen from the bottom, of an operation key in another configuration in the multidirectional operation unit in accordance with the second exemplary embodiment of the present invention. 
     FIG. 10 is a front section view of a conventional multidirectional operation switch. 
     FIG. 11 is an exploded perspective of the conventional multidirectional operation switch. 
     FIG. 12 is a plan view of a box case of the conventional multidirectional operation switch. 
     FIG. 13 is a front section view illustrating the tilting state of the conventional multidirectional operation switch. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A switch mechanism of the present invention, and a multidirectional operation switch and multidirectional operation unit employing this switch mechanism are described below with reference to FIGS. 1 to  9 . 
     First Embodiment 
     FIG. 1 is a front section view of the multidirectional operation switch in a first exemplary embodiment having the switch mechanism of the present invention. 
     FIG. 2 is an exploded perspective of the above switch. 
     In FIGS. 1 and 2, box case  1  is made of an insulating resin, and has a cavity with an open top. 
     Dome-shaped flexible contact  11  is made of a convex-shaped thin resilient metal sheet. 
     Dome-shaped flexible contact  11  is housed in the cavity of box case  1  such that its center is positioned at the center of the cavity. 
     Operating member  12  is disposed on dome-shaped flexible contact  11 . 
     Operating member  12  is configured with shaft  12 B and flange  12 A at the bottom which is integrally formed with shaft  12 B. Over this flange  12 A, cover  2 , typically made of a metal sheet, covers the top opening of box case  1 , and is fixed to box case  1 . 
     Both the cavity of box case  1  and flange  12 A of operating member  12  are octagonal, and are configured to prevent any rotation by flange  12 A. Shaft  12 B of operating member  12  protrudes from through hole  2 A at the center of cover  2  for a tilting operation. 
     As shown in FIG. 3, eight fixed contacts  3 ,  4 ,  5 ,  6 ,  7 ,  8 ,  9 , and  10  are disposed at the cavity bottom of box case  1  along the circumference of a circle centering on the center of box case  1  at positions dividing the circumference into  8  equal portions. In addition, fixed contacts  3  to  10  are disposed inside the rim of dome-shaped flexible contact  11  projected onto the bottom face of the cavity of box case  1 . Fixed contacts  3  to  10  are fixed on the cavity bottom of box case  1 , typically by insert molding. 
     Fixed contacts  3  to  10  include the following three types of contacts. 
     i) First common contacts  3  and  7  which have electrically the same potential and are commonly used. 
     ii) Second common contacts  5  and  9  which have electrically the same potential and are commonly used. 
     iii) Independent contacts  4 ,  6 ,  8 , and  10  which are electrically independent. 
     As described above, there are two systems of common contacts. 
     Each contact is disposed in the clockwise sequence of first common contact  3 , independent contact  4 , second common contact  5 , independent contact  6 , first common contact  7 , independent contact  8 , second common contact  9 , and independent contact  10 . 
     In other words, the fixed contacts are aligned regularly such that the common contact and independent contact are disposed alternately, and the first common contact and second common contact are also disposed alternately. In addition, a group in the sequence of the first common contact, independent contact, second common contact, and independent contact is disposed repeatedly in turn on the circumference. 
     First common contacts  3  and  7 , second common contacts  5  and  9 , and independent contacts  4 ,  6 ,  8 , and  10  which are electrically independent are electrically coupled respectively to first common terminals  13  and  17 ; second common terminals  15  and  19 ; and independent terminals  14 ,  16 ,  18 , and  20 , which are disposed outside case  1  for lead-out. 
     Terminals  13  to  20  are disposed, four each, to the opposing outer walls of box case  1 . 
     In the above description, four terminals, in total, that are first common terminals  13  and  17  and second common terminals  15  and  19 , are provided as terminals for first common contacts  3  and  7  and second common contacts  5  and  9 . Alternatively, first common contacts  3  and  7  may be connected and second common contacts  5  and  9  may be connected in box case  1  respectively for providing only one terminal each for first and second common contacts as first common terminal and second common terminal. 
     On the bottom face of flange  12 A of operating member  12 , eight pushing elements  12 D are provided. 
     Pushing elements  12 D are disposed at the middle of adjacent contacts among contacts  3  to  10 , and protrude downward from flange  12 A. 
     Pushing elements  12 D contact the top face of dome-shaped flexible contact  11  positioned by and housed in box case  1 . This makes the top face of flange  12 A of operating member  12  push against the bottom of cover  2 , making operating member  12  maintain its vertical neutral position. 
     Next, the operation of the multidirectional operation switch as configured above is described. 
     Firstly, FIG. 1 shows the normal state when connection between any pair of the contacts is in the OFF state. 
     Then, as shown by arrow  202  in FIG. 4, a left top face of key  22  mounted on top end  12 C of operating member  12  is pushed downward. In other words, shaft  12 B is tilted toward the intermediate position between independent contact  4  and second common contact  5 . Here, operating member  12  tilts about a fulcrum at the right top of flange  12 A. This makes pushing element  12 D on the left bottom face of flange  12 A push dome-shaped flexible contact  11  and partially invert it. Dome-shaped flexible contact  11  provides a tactile ‘click’ and its inverted portion contacts independent contact  4  and second common contact  5  disposed at the bottom of box case  1 . Accordingly, independent terminal  14  and second common terminal  15  for lead-out come into contact. 
     FIG. 4 only illustrates the case when dome-shaped flexible contact  11  contacts second common contact  5 . However, dome-shaped flexible contact  11  pushed by pushing element  12 D is also contacting independent contact  4  although it is not illustrated. 
     Since only a portion of dome-shaped flexible contact  11  pushed by pushing element  12 D is inverted, dome-shaped flexible contact  11  does not contact fixed contacts  3  and  6  to  10  which are out of the direction that shaft  12 B tilts. 
     When the pressing force applied to key  22  is released, the resilience of dome-shaped flexible contact  11  pushes back pushing element  12 D on the bottom face of operating member  12 , and operating member  12  returns to its vertical neutral position. Dome-shaped flexible contact  11  separates from independent contact  4  and second common contact  5 , and the switch returns to the OFF state. 
     In the same way, one of the first and second common contacts and one of the independent contacts are electrically coupled in response to the respective tilting direction of operating member  12  via dome-shaped flexible contact  11  by changing the direction in which key  22  is pushed, i.e., changing the direction in which operating member  12  is tilted. More specifically, one of first common terminals  13  and  17  or one of second common terminals  15  and  19  and one of lead-out terminals  14 ,  16 ,  18 , and  20  are electrically coupled. 
     As described above, multiple contacts are provided under and inside an area of one dome-shaped flexible contact  11  in the multidirectional operation switch having the switch mechanism of the present invention. These multiple contacts consist of three types: two systems of common contacts, i.e., first common contacts  3  and  7  and second common contacts  5  and  9  which have electrically the same potential and are used commonly; and independent contacts  4 ,  6 ,  8 , and  10  which are electrically independent. 
     Contacts  3  to  10  are aligned in the clockwise sequence of first common contact  3 , independent contact  4 , second common contact  5 , independent contact  6 , first common contact  7 , independent contact  8 , second common contact  9 , and independent contact  10 . In other words, the common contact and independent contact are disposed alternately, and the first common contact and second common contact are also disposed alternately as common contacts. This makes it possible to switch a pair of common contact and independent contact when operating member  12  is tilted in a given direction. Accordingly, the direction of operation can be specified. 
     As shown in FIG. 3, it is apparent that contacts  3  to  10  can be disposed counterclockwise. 
     Moreover, with respect to two systems of common contacts, multiple common contacts in each system can be commonly connected to one terminal respectively for lead-out. This enables the reduction of the number of lead-out terminals, offering a downsized switch. 
     Next, the number of input ports required in a microcomputer (not illustrated) for receiving and processing ON and OFF signals from this switch are described. 
     For the conventional switch mechanism as described with reference to FIG. 12, common terminal  63  is connected to the ground and eight terminals are needed for connecting the remaining terminals  43  to  50 . 
     On the other hand, the switch mechanism of the present invention can be configured, in total, with six terminals: first common terminal, second common terminal, and four independent terminals. Accordingly, two input ports can be eliminated. This offers a design-friendly switch which enables more simplified circuit design, typically of wiring boards in an apparatus. 
     FIG. 5 is a perspective seen from the bottom of the operating member in another configuration. Pushing element  25  on the bottom face of flange  24 A of operating member  24  can result in a shape protruding toroidally at an area corresponding to contacts  3  to  10  at the cavity bottom of box case  1 . 
     Pushing element  25  with the shape shown in FIG. 5 enables the further reduction of incorrect operation of the switch, compared to the aforementioned configuration. 
     The reasons are given next. 
     Pushing element  25  results in a uniform height through the circumference. If operating member  24  tilts directly to the fixed contact, which is out of the given operating directions, toward the direction of second common contact  5 , for example, the portion of dome-shaped flexible contact  11  pressed by the portion of annular pushing element  25  corresponding to the tilted direction is inverted. This partial inversion of dome-shaped flexible contact  11  is halted when it contacts second common contact  5 . In other words, the tilting movement of operating member  24  in the tilting direction is halted when dome-shaped flexible contact  11  touches second common contact  5 . Dome-shaped flexible contact  11  is thus prevented from contacting independent contact  4  or  6  adjacent to second common contact  5 , maintaining the OFF state between contacts. Accordingly, incorrect operation of the switch by operating to this direction can be reduced. 
     The first exemplary embodiment describes an example of a switch mechanism having eight fixed contacts. The idea of the switch mechanism of the present invention is also applicable to other switch mechanisms having fixed contacts in multiples of  4 . 
     In the switch mechanism of the present invention, a conductor other than a dome-shaped flexible contact can be used for electrically coupling fixed contacts as aligned above. 
     Second Embodiment 
     An apparatus equipped with the switch mechanism as described in the first exemplary embodiment is briefly described in a second exemplary embodiment. 
     FIG. 6 is an exploded perspective of a multidirectional operation unit in the second exemplary embodiment equipped with the switch mechanism of the present invention. 
     FIG. 7 is a top view of the multidirectional operation unit. 
     FIG. 8 is a section view taken along Line  8 — 8  in FIG.  7 . 
     In these Figures, wiring board  101  has a multi-layer wiring structure, and is positioned by and placed in housing  110  of the apparatus. On the top face of wiring board  101 , eight fixed contacts  123  to  130  are disposed for configuring the switch mechanism of the present invention. 
     Fixed contacts  123  to  130  are disposed toroidally at equal intervals on the circumference centering on a predetermined center, seen from the top. 
     These fixed contacts  123  to  130  consist of three types: two systems of common contacts, i.e., first common contacts  123  and  127  and second common contacts  125  and  129  which have electrically the same potential and are used commonly; and independent contacts  124 ,  126 ,  128 , and  130  which are electrically independent. 
     Each contact is aligned in the clockwise sequence of first common contact  123 , independent contact  124 , second common contact  125 , independent contact  126 , first common contact  127 , independent contact  128 , second common contact  129 , and independent contact  130 . 
     In other words, fixed contacts  123  to  130  in the second exemplary embodiment are also aligned such that a group in the sequence of first common contact, independent contact, second common contact, and independent contact is repeated twice. 
     First common contacts  123  and  127  are electrically coupled inside wiring board  101 , and led out by one lead-out member  151 . 
     Second common contacts  125  to  129  are also led out by one lead-out member  152 . 
     Electrically independent contacts  124 ,  126 ,  128 , and  130  are led out by lead-out members  153  to  156  respectively. 
     In these Figures, other wirings and mounted electronic components which may exist are not indicated on wiring board  101 . 
     Dome-shaped flexible contact  160  is made of a convex-shaped thin resilient metal sheet. Dome-shaped flexible contact  160  is disposed on wiring board  101  such that it includes fixed contacts  123  to  130  beneath, and is attached to wiring board  101  using flexible cover tape  161 . 
     At this point, dome-shaped flexible contact  160  does not contact any of fixed contacts  123  to  130 . The center of dome-shaped flexible contact  160  is set in the center of the circumference where fixed contacts  123  to  130  are disposed. These are the same as in the first exemplary embodiment. 
     The use of cover tape  161  for attaching dome-shaped flexible contact  160  ensures that dome-shaped flexible contact  160  is maintained on wiring board  101 . In addition, this method makes a contact point between dome-shaped flexible contact  160  and each of fixed contacts  123  to  130  steady. Furthermore, a thin and inexpensive switch can be made feasible. 
     Dome-shaped flexible contact  160  which configures the switch mechanism of the present invention does not have a fixed contact which is always electrically coupled. Moreover, dome-shaped flexible contact  160  is restricted in the upward position by operation key  170  as described later. Accordingly, dome-shaped flexible contact  160  on wiring board  101  can simply be positioned by the side such as along the wall of a predetermined member. 
     Operation key  170  is disposed on dome-shaped flexible contact  160  via cover tape  161 . 
     Operation key  170  is approximately disc-shaped, and is exposed from hole  111  on housing  110  so that operation key  170  is operable at its top center. Upward limiter  170 A that protrudes in a circular collar shape, when seen from the top, fits to the bottom face of housing  110  to prevent operation key  170  from detaching. 
     Moreover, four notches  170 B are created on upward limiter  170 A. Tab  110 A protruding downward from housing  110  is inserted through each of these notches  170 B to restrict the rotation of operation key  170 . 
     Furthermore, in the bottom surface of operation key  170 , eight pushing elements  171  protruding downward are disposed at positions corresponding to respective intermediate positions between adjacent contacts among contacts  123  to  130 . 
     As shown in FIG. 8, pushing elements  171  are disposed so as to contact the top face of dome-shaped flexible contact  160  via cover tape  161 . This pushes the top face of upward limiter  170 A of operation key  170  against the bottom face of housing  110  around hole  111 , allowing operation key  170  to maintain its vertical neutral position. 
     As described above, members to limit the rotation or escape of operation key  170  are provided around hole  111  of housing  110 , and are fitted to operation key  170 . 
     This enables the apparatus height to be kept short and allowing the use of fewer components. 
     As shown in FIGS. 6 and 7, eight protrusions  170 C for recognition during operation are disposed on the top face of operation key  170  at positions corresponding to pushing elements  171 . 
     The center of operation key  170  to which protrusions are disposed on the circumference is disposed to the center of the circumference where fixed contacts  123  to  130  are disposed. 
     Notches  170 B are disposed at four points on straight limes perpendicular to each other including the center of the circle on which operation key  170  is disposed, but not at points on the straight line connecting the position where protrusion  170 C is disposed and the center of the circle of operation of button  170 . 
     In the section view in FIG. 8, to simplify the drawing, only a few pushing elements  171  of operation  170  close to the section are illustrated. For the same reason, in FIG. 8, protrusions  170 C of operation key  170  and fixed contacts on wiring board  101  are omitted. 
     The multidirectional operation unit in the second exemplary embodiment is configured as described above. 
     Next, the operation of this unit is described only briefly, since it is mostly the same as that of the multidirectional operation switch in the first exemplary embodiment. 
     First, in the normal state in which connection between any pair of the contacts is in the OFF state, as shown in FIG. 8, pressure is applied to operation key  170  from one of the protrusions  170 C for recognition. Operation key  170  then tilts about a fulcrum at a top corner of upward limiter  170 A at an opposing point symmetric to the pressed point. Pushing element  171  underneath protrusion  170 C where the pressure is applied pushes dome-shaped flexible contact  160  via cover tape  161 , and partially inverts dome-shaped flexible contact  160 . Dome-shaped flexible contact  160  provides a tactile ‘click’ and electrically couples only between corresponding fixed contacts. 
     Then, when the pressure is released, pushing element  171  on the bottom face of operation key  170  is pushed up from the bottom by the resilience of dome-shaped flexible contact  160 , and operation key  170  returns to its vertical neutral position. Operation key  170  returns to the normal state in which connection between contacts are all OFF. 
     As described above, the multidirectional operation unit in the second exemplary embodiment has fixed contacts aligned such that a group in the sequence, of first common contact, independent contact, second common contact, and independent contact is disposed repeatedly twice, in the same way as in the first exemplary embodiment. In addition, a pair of common contact and independent contact is switched by dome-shaped flexible contact  160 . The direction of operation can thus be specified. 
     Moreover, two systems of common contacts are respectively led out to lead-out terminals  151  and  152 . The small number of terminals results in greater flexibility in designing the pattern of wiring board  101 . Furthermore, the use of this multidirectional operation unit makes it possible to reduce the number of input ports on control parts, such as microcomputers for signal processing. 
     The multidirectional operation unit in the second exemplary embodiment also contributes to the slimming of apparatuses because this unit has a simple configuration and shorter height. 
     A conductor other than dome-shaped flexible contact  160  is also applicable for electrically coupling fixed contacts as aligned above. 
     Operation key  200  shown in FIG. 9 is also applicable instead of operation key  170  having pushing element  171 . Operation key  200  has annular pushing element  201  with a uniform height over through the circumference. As described in the first exemplary embodiment, this configuration limits the tilting movement of operation key  200  when it is pushed in the direction of the fixed contact which is not previously assigned for operation, reducing incorrect operation of the switch. 
     As described above, the switch mechanism of the present invention can specify operating directions using fewer fixed contacts. Accordingly, the use of this switch mechanism offers small multidirectional operation switches with fewer lead-out terminals. 
     Furthermore, the use of this switch mechanism offers simplified and thinner multidirectional operation units.