Patent Publication Number: US-11024471-B2

Title: Push switch

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. national stage application of the PCT International Application No. PCT/JP2018/031470 filed on Aug. 27, 2018, which claims the benefit of foreign priority of Japanese patent application No. 2017-169015 filed on Sep. 1, 2017 and Japanese patent application No. 2018-009208 filed on Jan. 23, 2018, the contents all of which are incorporated herein by reference 
     TECHNICAL FIELD 
     The present disclosure generally relates to push switches. The present disclosure specifically relates to a push switch closed or opened by deformation of a movable component. 
     BACKGROUND ART 
     Some known push switches each include a case that includes switch contacts, and a protective sheet that covers the case (see PTL 1, for example). 
     A push switch disclosed in PTL 1 includes a case (switch case) that has a depression that opens upward. A bottom surface (inner bottom surface) of the depression of the case includes a stationary contact (central stationary contact). Further, a movable component (a second movable contact) is disposed in the depression. The movable component is an elastic metal sheet that is curved like a dome that protrudes upward. The movable component is substantially circular. A protective sheet is disposed on the case to cover the depression. 
     When the push switch is operated, force is applied to a top surface of the protective sheet. The force is transferred to the movable component. Consequently, the movable component deforms (elastic reversal). Consequently, an underside of the movable component comes into contact with the stationary contact. Consequently, the push switch is closed. If the force ceases to be applied to the protective sheet, the movable component deforms into an original shape (a shape like a dome that protrudes upward) (elastic restoration). Consequently, the push switch is opened. 
     CITATION LIST 
     Patent Literature 
     PTL 1: Unexamined Japanese Patent Publication No. 2008-41603 
     SUMMARY OF THE INVENTION 
     A push switch according to an aspect of the present disclosure includes a stationary contact and a movable contact. The stationary contact includes a base material and a conductive layer that covers the base material. The movable contact is disposed opposite a contact surface of the stationary contact. The movable contact is movable between a first position where the movable contact is in contact with the contact surface and a second position where the movable contact is apart from the contact surface. The stationary contact has a groove that divides the contact surface into a plurality of areas. Connection surfaces connect respective opening edges of the groove with a bottom of the groove. Each of the connection surfaces has a slope that is inclined at an acute angle relative to the contact surface. 
     The present disclosure has an advantage that electrical properties are less likely to vary. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of a push switch according to an exemplary embodiment of the present disclosure. 
         FIG. 2A  is a plan view of the push switch according to the exemplary embodiment of the present disclosure. 
         FIG. 2B  is an elevation view of the push switch according to the exemplary embodiment of the present disclosure. 
         FIG. 3A  is a plan view of the push switch according to the exemplary embodiment of the present disclosure. In  FIG. 3A , a protective sheet, a pressing component, and a movable component are removed from the push switch. 
         FIG. 3B  is an enlarged view of area Z 1  in  FIG. 3A . 
         FIG. 4A  is a plan view of the push switch according to the exemplary embodiment of the present disclosure. In  FIG. 4A , the protective sheet is removed from the push switch. 
         FIG. 4B  is an enlarged view of area Z 1  in  FIG. 4A . 
         FIG. 5A  is a schematic cross-sectional view of the push switch according to the exemplary embodiment of the present disclosure. In  FIG. 5A , the push switch is not operated. 
         FIG. 5B  is a schematic cross-sectional view of the push switch according to the exemplary embodiment of the present disclosure. In  FIG. 5B , the push switch is operated. 
         FIG. 6  is a schematic cross-sectional view of the push switch according to the exemplary embodiment of the present disclosure taken along line X 2 -X 2  in  FIG. 2A . 
         FIG. 7A  is a schematic cross-sectional view of an aspect of one of enlarging depressions of the push switch according to the exemplary embodiment of the present disclosure. 
         FIG. 7B  is a schematic cross-sectional view of an aspect of one of enlarging depressions of the push switch according to the exemplary embodiment of the present disclosure. 
         FIG. 8A  is a plan view of an important part that illustrates an aspect of one of enlarging depressions of the push switch according to the exemplary embodiment of the present disclosure. 
         FIG. 8B  is a plan view of an important part that illustrates an aspect of one of enlarging depressions of the push switch according to the exemplary embodiment of the present disclosure. 
         FIG. 9  is a perspective view of an important part that illustrates a stationary contact of the push switch according to the exemplary embodiment of the present disclosure. 
         FIG. 10A  is an enlarged view of area Z 1  in  FIG. 5A . 
         FIG. 10B  is an enlarged schematic view of area Z 1  in  FIG. 10A . 
         FIG. 10C  is an enlarged schematic view of area Z 1  in  FIG. 10B . 
         FIG. 11A  is a schematic view that illustrates an example of a method for manufacturing a stationary contact of the push switch according to the exemplary embodiment of the present disclosure. 
         FIG. 11B  is a schematic view that illustrates an example of the method for manufacturing the stationary contact of the push switch according to the exemplary embodiment of the present disclosure. 
         FIG. 11C  is a schematic view that illustrates an example of the method for manufacturing the stationary contact of the push switch according to the exemplary embodiment of the present disclosure. 
         FIG. 12A  is a perspective view of an important part that illustrates corners of the push switch according to the exemplary embodiment of the present disclosure. The corners each have a first shape. 
         FIG. 12B  is a plan view that illustrates the corners of the push switch according to the exemplary embodiment of the present disclosure. The corners each have the first shape. 
         FIG. 12C  is a schematic cross-sectional view of the corners of the push switch according to the exemplary embodiment of the present disclosure taken along line X 1 -X 1  in  FIG. 12B . The corners each have the first shape. 
         FIG. 13A  is a perspective view of an important part that illustrates corners of the push switch according to the exemplary embodiment of the present disclosure. The corners each have a second shape. 
         FIG. 13B  is a plan view that illustrates the corners of the push switch according to the exemplary embodiment of the present disclosure. The corners each have the second shape. 
         FIG. 13C  is a schematic cross-sectional view of the corners of the push switch according to the exemplary embodiment of the present disclosure taken along line X 1 -X 1  in  FIG. 13B . The corners each have the second shape. 
         FIG. 14A  is an enlarged perspective view of an important part that illustrates corners of the push switch according to the exemplary embodiment of the present disclosure. The corners each have the first shape. 
         FIG. 14B  is an enlarged perspective view of an important part that illustrates corners of the push switch according to the exemplary embodiment of the present disclosure. The corners each have the second shape. 
         FIG. 15  is a graph that illustrates a relation between a shape of each of corners and magnitude of a stress that acts on a movable contact, in the push switch according to the exemplary embodiment of the present disclosure. 
         FIG. 16  is a plan view of the push switch according to the exemplary embodiment of the present disclosure. In  FIG. 16 , the protective sheet is removed from the push switch. 
         FIG. 17A  is a schematic cross-sectional view of an aspect of a stationary contact of the push switch according to the exemplary embodiment of the present disclosure. 
         FIG. 17B  is a schematic cross-sectional view of an aspect of the stationary contact of the push switch according to the exemplary embodiment of the present disclosure. 
         FIG. 17C  is a schematic cross-sectional view of an aspect of the stationary contact of the push switch according to the exemplary embodiment of the present disclosure. 
         FIG. 18A  is a plan view of an important part that illustrates an aspect of a stationary contact of the push switch according to the exemplary embodiment of the present disclosure. 
         FIG. 18B  is a plan view of an important part that illustrates an aspect of a stationary contact of the push switch according to the exemplary embodiment of the present disclosure. 
         FIG. 18C  is a plan view of an important part that illustrates an aspect of a stationary contact of the push switch according to the exemplary embodiment of the present disclosure. 
         FIG. 19A  is a plan view of a push switch according to a first example of modifications of the exemplary embodiment of the present disclosure. In  FIG. 19A , a protective sheet is removed from the push switch. 
         FIG. 19B  is a plan view of a push switch according to a second example of modifications of the exemplary embodiment of the present disclosure. In  FIG. 19B , a protective sheet is removed from the push switch. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     In such a push switch as described above, when the push switch is operated, an underside of a central portion of a movable contact comes into contact with a top surface of a stationary contact. Consequently, the movable contact electrically connects with the stationary contact. However, the top surface of the stationary contact (a contact surface with which the movable contact is in contact) is one flat plane. Therefore, for example, if foreign matter enters between the stationary contact and the movable contact, electrical properties of the push switch may deteriorate. 
     The present disclosure allows electrical properties to be less likely to vary. 
     Exemplary Embodiment 
     (1) Outline 
     As illustrated in  FIGS. 1 to 4B , push switch  1  according to a present exemplary embodiment includes case  2 , movable component  3 , and contacts  4 . 
     Case  2  has depression  21 . Movable component  3  has pressure receiving portion  33 , and is disposed in depression  21 . When pressure receiving portion  33  is pushed toward bottom surface  211  of depression  21 , movable component  3  deforms. Consequently, contacts  4  are closed or opened. Contacts  4  include (first) stationary contact  7  and movable contact  8 . Stationary contact  7  is fixed to case  2 . Movable component  3  has movable contact  8  that is disposed opposite contact surface  73  of stationary contact  7 . Deformation of movable component  3  moves movable contact  8  between a closed position (first position) where movable contact  8  is in contact with contact surface  73  and an open position (second position) where movable contact  8  is apart from contact surface  73 . That is to say, contacts  4  are closed while movable contact  8  is at the closed position (first position). Alternatively, contacts  4  are open while movable contact  8  is at the open position (second position). 
     In such push switch  1 , movable component  3  deforms and may rub against bottom surface  211  of depression  21  of case  2 . If excessive force is applied to movable component  3 , powder P 1  may be scraped from case  2  (see  FIG. 3B ). Although details will be described later, in the present exemplary embodiment, contact portions  212  of bottom surface  211  of depression  21  expose one of metal components  9 . Movable component  3  is in contact with contact portions  212 . Therefore, movable component  3  rubs against the one of metal components  9  at contact portions  212 . Therefore, powder P 1  may be scraped from the one of metal components  9 . Scraped powder P 1  that has been generated as described above may accumulate at contact portions  212  with which movable component  3  is in contact. Contact portions  212  are portions of bottom surface  211  of depression  21  of case  2 . If scraped powder P 1  accumulates at contact portions  212 , tactility and electrical properties of push switch  1  may vary. 
     In the present disclosure, bottom surface  211  of depression  21  of case  2  exposes metal component  92 . Part of metal component  92  functions as stationary contact  921 . In the following description, metal component  92  that is exposed forms part of the bottom surface of depression  21 . In the description of the present disclosure, a top surface of stationary contact  921  (metal component  92 ) exposed by bottom surface  211  of depression  21  of case  2  is part of bottom surface  211  of depression  21  of case  2 , as illustrated in  FIGS. 7A and 7B , for example. Similarly, in the description, part of a top surface of metal component  92  exposed by bottom surfaces  221  of enlarging depressions  22  is part of bottom surfaces  221  of enlarging depressions  22  of case  2 . Details of  FIGS. 7A and 7B  will be described later. 
     As a countermeasure against scraped powder P 1  described above, push switch  1  according to the present exemplary embodiment includes enlarging depressions  22  in case  2 , as illustrated in  FIGS. 3A and 3B . Enlarging depressions  22  are adjacent to depression  21 . That is to say, case  2  also has enlarging depressions  22 . Enlarging depressions  22  are adjacent to respective contact portions  212  of bottom surface  211  of depression  21 . Movable component  3  is in contact with contact portions  212 . Further, depression  21  and enlarging depressions  22  are integrally made. That is to say, a depression of case  2  is depression  21  enlarged by enlarging depressions  22 . In the present disclosure, the expression “are adjacent to” means that “are adjacent to and connect with”. That is to say, the expression “are adjacent to” means that “are adjacent to each other”. Further, in the present disclosure, the expression “enlarging” means that “enlarging an extent”. That is to say, in the present exemplary embodiment, case  2  has enlarging depressions  22 . Each of enlarging depressions  22  extends outward relative to corresponding one of contact portions  212 . Movable component  3  is in contact with contact portions  212 . Contact portions  212  are portions of bottom surface  211  of depression  21 . Therefore, if powder P 1  is scraped from case  2  or the one of metal components  9  at contact portions  212 , scraped powder P 1  moves into enlarging depressions  22  from contact portions  212  in depression  21 . Therefore, in push switch  1 , scraped powder P 1  is less likely to accumulate at contact portions  212  with which movable component  3  is in contact. Contact portions  212  are portions of bottom surface  211  of depression  21  of case  2 . Therefore, push switch  1  has an advantage that scraped powder P 1  is less likely to vary tactility and electrical properties of push switch  1 . 
     In push switch  1  according to the present exemplary embodiment, stationary contact  7  has contact surface  73  that is opposite movable contact  8 , and grooves  74  that divide contact surface  73  into a plurality of areas  731 , as illustrated in  FIG. 9 . Since grooves  74  divide contact surface  73  into the plurality of areas  731 , a structure-for-contact-at-a-plurality-of-positions is made for contacts  4 . The structure-for-contact-at-a-plurality-of-positions allows movable contact  8  to be in contact with a plurality of positions of stationary contact  7 . Therefore, for example, even if foreign matter enters between stationary contact  7  and movable contact  8 , electrical properties of push switch  1  are less likely to deteriorate, compared with a case in which contact surface  73  of stationary contact  7  is one flat plane. 
     In case of push switch  1  that has the structure-for-contact-at-a-plurality-of-positions, however, if excessive force is applied to movable component  3 , part of conductive layer  72  of stationary contact  7  (see  FIG. 10B ) is likely to be removed from base material  71  of stationary contact  7  (see  FIG. 10B ). If part of conductive layer  72  is removed, electrical properties of push switch  1  may vary. 
     In push switch  1  according to the present exemplary embodiment, each of grooves  74  has connection surfaces  753  that connect respective opening edges  751  of each of grooves  74  with bottom  752  of each of grooves  74 , as illustrated in  FIGS. 10A to 10C . Each of connection surfaces  753  has slope  754 , as a countermeasure against the removal of conductive layer  72  described above. Each of slopes  754  is inclined at acute angles θ relative to contact surface  73  (see  FIG. 10C ). The configuration allows conductive layer  72  to be less likely to be damaged at opening edges  751  of grooves  74 . Further, the configuration allows a stress concentration to be less likely to occur at opening edges  751  of grooves  74  when movable contact  8  is pushed against stationary contact  7 . Therefore, push switch  1  has an advantage that conductive layer  72  is less likely to be removed, and thus electrical properties of push switch  1  are less likely to vary though push switch  1  has the structure-for-contact-at-a-plurality-of-positions. 
     (2) Details 
     Push switch  1  that will be described later is applied to controls of various devices, such as personal digital assistants, devices in a vehicle, and home appliances. For example, push switch  1  is attached to a printed circuit board in a housing of such a device. In that case, the housing includes an operational button, for example, at a position that corresponds to push switch  1 . Consequently, a user indirectly operates push switch  1  through the operational button by pressing down the operational button. 
     Hereinafter, a top surface of case  2  is a surface of case  2  where depression  21  is made, unless otherwise specified. Further, an “upward direction” and a “downward direction” are along a depth of depression  21 , unless otherwise specified. Further, a “rightward direction” is a direction in which first terminal  11  that will be described later protrudes from case  2 . A “leftward direction” is a direction in which second terminal  12  that will be described later protrudes from case  2 . A forward direction and a backward direction (directions that are perpendicular to a paper surface of  FIG. 2B ) are perpendicular to all the upward direction, the downward direction, the rightward direction, and the leftward direction. That is to say, the upward direction, the downward direction, the leftward direction, the rightward direction, the forward direction, and the backward direction are defined as represented by an arrow that points “upward”, an arrow that points “downward”, an arrow that points “leftward”, an arrow that points “rightward”, an arrow that points “forward”, and an arrow that points “backward”, respectively, in  FIG. 1 , for example. However, the directions do not limit a direction in which push switch  1  is used. Further, the arrows that point the respective directions are illustrated only for explanation in the drawings. The arrows are unsubstantial. 
     (2.1) Basic Configuration 
     As illustrated in  FIGS. 1 to 4B , push switch  1  according to the present exemplary embodiment also includes protective sheet  5 , pressing component  6 , and metal components  9 , in addition to case  2 , movable component  3 , and contacts  4 . In the following description, push switch  1  is not operated. That is to say, push switch  1  is not pushed, unless otherwise specified. 
     Case  2  is made of a synthetic resin that possesses electrical insulation. Case  2  has a shape like a cuboid. Case  2  has a thin thickness and has a flat top surface and a flat underside. Top surface  23  of case  2  is a surface in a thickness direction of case  2 . Top surface  23  has depression  21 . Depression  21  opens upward (in a first direction). In the present exemplary embodiment, depression  21  has a shape like an ellipse whose lateral length is longer than a vertical length of the ellipse, in a top view. A center of depression  21  corresponds to a center of top surface  23 . Bottom surface  211  of depression  21  is not flat. In depression  21 , there is a difference in depth at least between a central portion of bottom surface  211  and a periphery of bottom surface  211 . In the present exemplary embodiment, there is a step between the central portion of bottom surface  211  and the periphery of bottom surface  211 , and the central portion of bottom surface  211  is lower than the periphery of bottom surface  211 . In other words, in depression  21 , the central portion is deeper than the periphery. Four corners of case  2  are chamfered, in a top view. However, the chamfering is not essential to push switch  1 , and case  2  may not be appropriately chamfered. 
     Bottom surface  211  of depression  21  has contact portions  212  at a periphery of bottom surface  211  (see  FIGS. 3A and 3B ). Contact portions  212  are portions of bottom surface  211  of depression  21 . Movable component  3  is in contact with contact portions  212 . In the present exemplary embodiment, a plurality of areas (four areas in the present exemplary embodiment) of movable component  3  are in contact with bottom surface  211  of depression  21 . Therefore, case  2  has the plurality of (four in the present exemplary embodiment) contact portions  212 . Four contact portions  212  are at four corners of bottom surface  211  of depression  21 . 
     Top surface  23  of case  2  is a surface in a thickness direction of case  2 . Top surface  23  also has enlarging depressions  22 . Enlarging depressions  22  are adjacent to respective contact portions  212  of bottom surface  211  of depression  21 . Enlarging depressions  22  each have a shape that enlarges depression  21 . Enlarging depressions  22  are outside respective contact portions  212  (are opposite a center of bottom surface  211 ), and thus enlarges depression  21 . In  FIGS. 3A and 3B , imaginary lines L 1  represent boundaries between depression  21  and enlarging depressions  22 . That is to say, depression  21  is inside imaginary lines L 1  (is on a side of a center of bottom surface  211  relative to imaginary lines L 1 ) in  FIG. 3A . Further, enlarging depressions  22  are outside imaginary lines L 1  (are opposite the center of bottom surface  211 ) in  FIG. 3A . 
     The plurality of (four in the present exemplary embodiment) enlarging depressions  22  are adjacent to the plurality of (four in the present exemplary embodiment) respective contact portions  212 . That is to say, in the present exemplary embodiment, case  2  has depression  21  and the plurality of enlarging depressions  22 . Further, depression  21  and enlarging depressions  22  are integrally made. The plurality of enlarging depressions  22  are outside four corners of a periphery of depression  21 , in a top view. The plurality of enlarging depressions  22  increase an area of an opening of depression  21 . Enlarging depressions  22  form spaces where scraped powder P 1  that has been generated in depression  21  enters. The details will be described in section “(2.3) Countermeasure against scraped powder”. 
     Metal components  9  include first metal component  91  and second metal component  92 . First metal component  91  and second metal component  92  are each a conductive metal sheet. Case  2  retains first metal component  91  and second metal component  92 . In the present exemplary embodiment, first metal component  91  and second metal component  92 , and case  2  are integrally made by insert molding. That is to say, case  2  that contains inserts that are metal components  9  (first metal component  91  and second metal component  92 ) is made by insert molding. 
     First metal component  91  has (first) stationary contact  7  and first terminal  11 . Stationary contact  7  protrudes upward from a top surface of first metal component  91 . Stationary contact  7  is substantially circular, in a top view. Second metal component  92  has (second) stationary contact  921  and second terminal  12 . Bottom surface  211  of depression  21  exposes stationary contact  7  and stationary contact  921 . Depression  21  exposes stationary contact  7  at a central portion of depression  21 . Depression  21  exposes stationary contact  921  at a periphery of depression  21 . Stationary contact  7  protrudes upward from bottom surface  211  of depression  21 . An area of first metal component  91  around stationary contact  7  is substantially flush with bottom surface  211 . Further, stationary contact  921  is substantially flush with bottom surface  211 . Bottom surfaces  221  of four enlarging depressions  22  also expose stationary contact  921 . 
     One of metal components  9  has pin receiving portions  93  at positions that correspond to enlarging depressions  22 . Retaining pins Y 1  (see  FIG. 6 ) are in contact with pin receiving portions  93  to retain the one of metal components  9  when case  2  is molded (is made by insert molding). Stationary contact  921  has pin receiving portions  93  in the present exemplary embodiment because enlarging depressions  22  expose stationary contact  921  of second metal component  92 . In the present exemplary embodiment, a case is exemplified in which retaining pins Y 1  are in contact with an underside of the one of metal components  9  (stationary contact  921 ). Therefore, pin receiving portions  93  are under the underside of the one of metal components  9 . 
     First terminal  11  protrudes from a right side of case  2 . Second terminal  12  protrudes from a left side of case  2 . More specifically, first terminal  11  protrudes rightward from the right side of case  2 . Further, second terminal  12  protrudes leftward from the left side of case  2 . An underside of first terminal  11  and an underside of second terminal  12  are flush with an underside of case  2 . First terminal  11  and second terminal  12  are mechanically joined to and electrically connected with conductive components on a printed circuit board by soldering, respectively, for example. 
     Stationary contact  7  is electrically connected with first terminal  11  by part of first metal component  91  that is embedded in case  2 . Similarly, stationary contact  921  is electrically connected with second terminal  12  by part of second metal component  92  that is embedded in case  2 . First metal component  91  is electrically insulated from second metal component  92 . 
     Stationary contact  7  has contact surface  73  (a top surface in the present exemplary embodiment) that is opposite movable contact  8 . A shape of stationary contact  7  will be described in detail in section “(2.4) Stationary contact”. Further, stationary contact  7  has grooves  74  that divide contact surface  73  into a plurality of areas  731  (see  FIG. 9 ). 
     Movable component  3  is disposed in depression  21  of case  2 , as illustrated in  FIGS. 4A and 4B . Movable component  3  includes elastic sheets, such as metal sheets, for example, stainless-steel (SUS). In the present exemplary embodiment, movable component  3  includes a plurality of (three in the present exemplary embodiment) leaf springs  30  stacked together. The plurality of leaf springs  30  have a substantially same shape. 
     Movable component  3  has a shape that corresponds to depression  21 . Further, movable component  3  is slightly smaller than depression  21 , and thus can be disposed in depression  21 . That is to say, in the present exemplary embodiment, movable component  3  has a shape like an ellipse whose lateral length is longer than a vertical length of the ellipse, in a top view. A top surface of movable component  3  (a top surface of uppermost leaf spring  30 ) has a central portion that forms pressure receiving portion  33  (see  FIG. 1 ). That is to say, the central portion of the top surface of movable component  3  functions as pressure receiving portion  33 . Pressure receiving portion  33  receives force applied from an outside of push switch  1  to push switch  1  when push switch  1  is operated (hereinafter referred to as “operational force”). 
     Movable component  3  has a shape like a dome curved in such manner that a central portion of movable component  3  protrudes upward. While movable component  3  is disposed in depression  21 , four corners of movable component  3  are in contact with bottom surface  211  of depression  21 , in a top view. That is to say, four areas of movable component  3  are in contact with contact portions  212  of bottom surface  211  of depression  21 , respectively. However, another area or other areas of movable component  3  may be in contact with bottom surface  211 . 
     An underside of movable component  3  (an underside of lowermost leaf spring  30 ) is plated with gold (Au) or silver (Ag), for example. Consequently, a conductive film is made on the whole underside of movable component  3 . Part of the conductive film that corresponds to a central portion of movable component  3  (pressure receiving portion  33 ) forms movable contact  8 . At least four areas of movable component  3  are electrically connected with stationary contact  921  exposed by bottom surface  211 . The at least four areas of movable component  3  are in contact with contact portions  212  of bottom surface  211 . When operational force acts on pressure receiving portion  33 , movable component  3  deforms and is bent downward. The details will be described in section “(2.2) Operations”. For example, movable component  3  deforms into a shape like a dome, as illustrated in  FIG. 5B . Consequently, a central portion of movable component  3  protrudes downward. At that time, movable contact  8  made on an underside of pressure receiving portion  33  comes into contact with stationary contact  7 . Consequently, movable contact  8  is electrically connected with stationary contact  7 . 
     That is to say, movable contact  8  and stationary contact  7  constitute contacts  4 . When pressure receiving portion  33  is pushed toward bottom surface  211  of depression  21 , movable component  3  deforms. Consequently, contacts  4  are closed or opened. More specifically, while operational force does not act on pressure receiving portion  33 , movable contact  8  is apart from stationary contact  7 . Therefore, contacts  4  are open. At that time, first metal component  91  is electrically insulated from second metal component  92 . Therefore, first terminal  11  is not connected with second terminal  12 . On the other hand, when operational force acts on pressure receiving portion  33 , movable contact  8  comes into contact with stationary contact  7 . Consequently, contacts  4  are closed. At that time, movable component  3  (or the conductive film made on an underside of movable component  3 ) electrically connects first metal component  91  with second metal component  92 . Therefore, first terminal  11  is connected with second terminal  12 . 
     Protective sheet  5  is a flexible sheet made of a synthetic resin. In the present exemplary embodiment, protective sheet  5  is made of a resin film that possesses heat resistance and electrical insulation. Protective sheet  5  is disposed on top surface  23  of case  2 . Protective sheet  5  covers whole depression  21 . Protective sheet  5  is joined to top surface  23  of case  2 . Consequently, protective sheet  5  closes an opening surface of depression  21 . Consequently, protective sheet  5  tightly closes depression  21 . Consequently, protective sheet  5  does not allow water and a flux to enter depression  21 . Consequently, protective sheet  5  protects contacts  4  and movable component  3  that are disposed in depression  21  against water and a flux. For example, a shape of a periphery of protective sheet  5  is substantially a same as a shape of a periphery of top surface  23  of case  2 , and is slightly larger than top surface  23 . A size of protective sheet  5  is at least a size that allows a portion (joined-portion  51 ) of protective sheet  5  to be joined to case  2 . 
     Protective sheet  5  has joined-portion  51  at a periphery of protective sheet  5 . Joined-portion  51  is joined to part of top surface  23  of case  2 . The part of top surface  23  of case  2  is a periphery of depression  21  and peripheries of enlarging depressions  22 . Joined-portion  51  is welded to case  2 . Therefore, an adhesive does not adhere to an underside of protective sheet  5 . The adhesive adheres to an underside of protective sheet  5  if joined-portion  51  and case  2  are joined together with the adhesive. In the present exemplary embodiment, joined-portion  51  is joined to top surface  23  of case  2  by laser welding. A method by which joined-portion  51  is joined to case  2  is not limited to welding. Joined-portion  51  may be joined to case  2  with an adhesive. Alternatively, part of joined-portion  51  may be joined to case  2  by welding, and part of joined-portion  51  may be joined to case  2  with an adhesive. 
     Pressing component  6  is disposed between protective sheet  5  and pressure receiving portion  33  of movable component  3 . Pressing component  6  is made of a synthetic resin, and possesses electrical insulation. Pressing component  6  has a shape like a disk. Pressing component  6  has a thin thickness and has a flat top surface and a flat underside. Pressing component  6  is disposed on a top surface of movable component  3 . An underside of pressing component  6  is in contact with pressure receiving portion  33 . A top surface of pressing component  6  is joined to an underside of a central portion of protective sheet  5  by laser welding, for example. Pressing component  6  transfers operational force applied to protective sheet  5  to pressure receiving portion  33  of movable component  3 . That is to say, when operational force acts on a top surface of protective sheet  5 , pressing component  6  transfers the operational force to pressure receiving portion  33 . Consequently, the operational force acts on a top surface of pressure receiving portion  33 . The above configuration allows pressure receiving portion  33  to be indirectly operated with pressing component  6  by pressing protective sheet  5 . A shape of pressing component  6  is not limited to a shape like a disk but may be a shape like a funnel. 
     (2.2) Operations 
     Next, operations of push switch  1  configured as described above will be described with reference to  FIGS. 5A and 5B .  FIG. 5A  is a cross-sectional view taken along line X 1 -X 1  in  FIG. 2A . 
     Push switch  1  is normally open. When push switch  1  is operated, contacts  4  are closed. When push switch  1  is operated, a central portion of protective sheet  5  is pushed. Consequently, protective sheet  5  transfers downward operational force to pressing component  6 . The expression “is pushed” means an operation that pushes a central portion of protective sheet  5  toward bottom surface  211  of depression  21  (downward). 
     When pressing component  6  transfers operational force to a top surface of pressure receiving portion  33 , pressure receiving portion  33  is pushed toward bottom surface  211  of depression  21  (downward). Consequently, movable component  3  gradually deforms. If magnitude of the operational force transferred to pressure receiving portion  33  exceeds a predetermined value, movable component  3  quickly buckles and largely deforms, as illustrated in  FIG. 5B . At that time, elastic force of movable component  3  that acts on pressure receiving portion  33  quickly varies. What is called reversal of movable component  3  deforms movable component  3  into a shape like a dome curved in such a manner that a central portion (pressure receiving portion  33 ) of movable component  3  protrudes downward, as illustrated in  FIG. 5B . Therefore, the deformation of movable component  3  provides click feeling to a user (operator) who pushes push switch  1 . When movable component  3  deforms into a shape like a dome that protrudes downward, movable contact  8  on an underside of movable component  3  comes into contact with stationary contact  7 , as illustrated in  FIG. 5B . Consequently, contacts  4  are closed. In this state, first terminal  11  is connected with second terminal  12 . 
     On the other hand, if movable component  3  has deformed into a shape like a dome that protrudes downward, and then operational force ceases to act on pressure receiving portion  33 , restoring force of movable component  3  restores movable component  3  to (movable component  3  deforms into) a shape like a dome curved in such a manner that a central portion (pressure receiving portion  33 ) of movable component  3  protrudes upward. At that time, elastic force of movable component  3  that acts on pressure receiving portion  33  quickly varies. Therefore, movable component  3  quickly returns to (deforms into) an original shape (a shape like a dome curved in such a manner that a central portion of movable component  3  protrudes upward). Therefore, the deformation of movable component  3  also provides click feeling to a user (operator) who pushes push switch  1  when the user ceases to push push switch  1 . Then, when movable component  3  deforms into a shape like a dome that protrudes upward, movable contact  8  on an underside of movable component  3  becomes apart from stationary contact  7 , as illustrated in  FIG. 5A . Consequently, contacts  4  are opened. In this state, first terminal  11  is not connected with second terminal  12 . 
     (2.3) Countermeasure Against Scraped Powder 
     Hereinafter, a structure that push switch  1  includes as a countermeasure against scraped powder P 1  will be described in detail with reference to  FIGS. 3A and 3B . Scraped powder P 1  is schematically illustrated for explanation in  FIG. 3B , for example. However, scraped powder P 1  is not a component of push switch  1 . 
     When push switch  1  according to the present exemplary embodiment is operated, movable component  3  deforms and may rub against bottom surface  211  of depression  21  of case  2 . If excessive force is applied to movable component  3 , for example, powder P 1  may be scraped from case  2 . Especially when an object collides with an operational button of a device that includes push switch  1  as one of controls, excessive force is more likely to be applied to movable component  3  than a case in which a user intentionally operates push switch  1 . Consequently, powder P 1  is more likely to be scraped. Further, the more times push switch  1  is used, the more likely powder P 1  is to be scraped. 
     In the present exemplary embodiment, contact portions  212  of bottom surface  211  of depression  21  expose one of metal components  9 , as described above. Movable component  3  is in contact with contact portions  212 . Therefore, movable component  3  rubs mainly against the one of metal components  9  at contact portions  212 . Therefore, powder P 1  may be scraped from the one of metal components  9 . In the present disclosure, the “scraped powder” is scraped from part of the one of metal components  9  since movable component  3  rubs against the one of metal components  9 . However, scraped powder P 1  is not only scraped from the one of metal components  9 , but also may be scraped from case  2  made of a synthetic resin since movable component  3  rubs against part of case  2  made of a synthetic resin. Scraped powder P 1  generated as described above may accumulate at contact portions  212  with which movable component  3  is in contact. Contact portions  212  are portions of bottom surface  211  of depression  21  of case  2 . If scraped powder P 1  accumulates at contact portions  212 , scraped powder P 1  may prevent movable component  3  from moving, or scraped powder P 1  may enter between movable component  3  and stationary contact  921 . Consequently, scraped powder P 1  may vary tactility and electrical properties of push switch  1 . 
     In push switch  1  according to the present exemplary embodiment, case  2  has enlarging depressions  22 , as illustrated in  FIGS. 3A and 3B . Therefore, push switch  1  according to the present exemplary embodiment deals with scraped powder P 1  described above. That is to say, enlarging depressions  22  are adjacent to contact portions  212  with which movable component  3  is in contact. Contact portions  212  are portions of bottom surface  211  of depression  21 . Therefore, if deformation of movable component  3  generates scraped powder P 1  at contact portions  212 , scraped powder P 1  enters enlarging depressions  22 . In other words, scraped powder P 1  that has been generated at contact portions  212  in depression  21  moves from contact portions  212  into enlarging depressions  22  that is connected with contact portions  212 , respectively, as illustrated in  FIG. 3B . The above configuration allows enlarging depressions  22  to function as pockets in which scraped powder P 1  that has been generated in depression  21  accumulates. Therefore, in push switch  1 , scraped powder P 1  is less likely to accumulate at contact portions  212  with which movable component  3  is in contact. Contact portions  212  are portions of bottom surface  211  of depression  21  of case  2 . Therefore, scraped powder P 1  is less likely to vary tactility and electrical properties of push switch  1 . 
     In the present exemplary embodiment, a side surface of each of enlarging depressions  22  has a pair of side surfaces  222 , as illustrated in  FIG. 3B . The pair of side surfaces  222  are inclined. Therefore, in a plane that is along bottom surface  211  of depression  21 , the farther from depression  21 , the smaller an area of an opening of each of enlarging depressions  22 . In other words, the closer to depression  21 , the larger an area of an opening of each of enlarging depressions  22  becomes due to the pair of side surfaces  222 . 
     That is to say, in a top view, the farther from depression  21 , the shorter a distance between the pair of side surfaces  222  of each of enlarging depressions  22  that are adjacent to depression  21 . 
     Further, in the present exemplary embodiment, one of the pair of side surfaces  222  (side surface  222  that is closer to a back side in  FIG. 3B ) is flush with side surface  213   a  of depression  21 . The other one of the pair of side surfaces  222  (side surface  222  that is closer to a front side in  FIG. 3B ) is curved and is connected with side surface  213   b  of depression  21 . 
     The configuration allows the pair of side surfaces  222  of each of enlarging depressions  22  to function as a structure that guides scraped powder P 1  from depression  21  into enlarging depressions  22 . Therefore, push switch  1  according to the present exemplary embodiment has an advantage that scraped powder P 1  that has been generated at contact portions  212  of depression  21  is more likely to enter enlarging depressions  22 . 
     In the present exemplary embodiment, movable component  3  has a lateral length that is longer than a vertical length of movable component  3 , in a top view. In such a case, preferably, a space in each of enlarging depressions  22  has a lateral length that is longer than a vertical length of the space in each of enlarging depressions  22 , as illustrated in  FIG. 4B . That is to say, if each of enlarging depressions  22  enlarged depression  21  equally in both vertically (backward in  FIG. 4B ) and laterally (rightward in  FIG. 4B ), imaginary line L 2  in  FIG. 4B  would be a side surface of each of enlarging depressions  22 . 
     If movable component  3  has a lateral length that is longer than a vertical length of movable component  3 , in a top view, an amount of lateral movement of movable component  3  relative to each of contact portions  212  is larger than an amount of vertical movement of movable component  3  relative to each of contact portions  212  when operational force acts on pressure receiving portion  33  of movable component  3 . Therefore, scraped powder P 1  is more likely to be generated laterally outside contact portions  212  than vertically outside contact portions  212 . Therefore, in the present exemplary embodiment, each of enlarging depressions  22  additionally enlarges depression  21  laterally (rightward in  FIG. 4B ) from imaginary line L 2 . Therefore, scraped powder P 1  that has been generated laterally outside contact portions  212  (to a right of one of contact portions  212  in  FIG. 4B ) efficiently accumulates in enlarging depressions  22 . 
     In the present exemplary embodiment, case  2  is made of a synthetic resin, and bottom surface  211  of depression  21  exposes metal components  9 . In that case, preferably, one of metal components  9  extends to bottom surfaces  221  of enlarging depressions  22 . That is to say, the one of metal components  9  extends from each of contact portions  212  of bottom surface  211  of depression  21  to bottom surface  221  of corresponding one of enlarging depressions  22 . Movable component  3  is in contact with contact portions  212 . Consequently, even if movable component  3  moves onto boundaries between depression  21  and each of enlarging depressions  22  (imaginary lines L 1 ), movable component  3  does not rub against case  2  made of a synthetic resin. Therefore, powder P 1  is less likely to be scraped from case  2  made of a synthetic resin. 
     Further, in the present exemplary embodiment, the one of metal components  9  has pin receiving portions  93  at positions that correspond to enlarging depressions  22 , as described above. Pin receiving portions  93  of the one of metal components  9  may deform because retaining pins Y 1  (drawn using a two-dot chain line) are in contact with pin receiving portions  93  while case  2  is molded, as illustrated in  FIG. 6 .  FIG. 6  is a cross-sectional view taken along line X 2 -X 2  in  FIG. 2A . In an example in  FIG. 6 , retaining pins Y 1  are inserted in pin holes  24  that extend through an underside of case  2 , respectively. Bottom surfaces of pin holes  24  expose pin receiving portions  93 , respectively. Surfaces of ends of retaining pins Y 1  are in contact with pin receiving portions  93 , respectively. If pin receiving portions  93  were at positions with which movable component  3  is in contact, such as contact portions  212 , deformation of pin receiving portions  93  would prevent movable component  3  from moving. In the present exemplary embodiment, pin receiving portions  93  are at positions that correspond to enlarging depressions  22 . Therefore, deformation of pin receiving portions  93  does not prevent movable component  3  from moving. That is to say, enlarging depressions  22  function as pockets in which scraped powder P 1  that has been generated in depression  21  accumulates, as described above. Therefore, movable component  3  basically is not in contact with bottom surfaces  221  of enlarging depressions  22 . Therefore, deformation of pin receiving portions  93  does not prevent movable component  3  from moving. 
     Preferably, case  2  has the plurality of contact portions  212  with which movable component  3  is in contact, as in the present exemplary embodiment. Contact portions  212  are portions of bottom surface  211  of depression  21 . Further, preferably, case  2  has the plurality of enlarging depressions  22  that are adjacent to the plurality of contact portions  212 , respectively. That is to say, enlarging depressions  22  are separate from each other, and are for respective contact portions  212 . Therefore, scraped powder P 1  that has been generated at each of contact portions  212  efficiently accumulates in enlarging depressions  22 . 
     Push switch  1  may include enlarging depressions  22  configured as exemplified in  FIGS. 7A to 8B .  FIGS. 7A and 7B  are enlarged views of an important part that corresponds to area Z 1  in  FIG. 6 . However, components that are not directly related to the following description, such as movable component  3 , are appropriately not illustrated in  FIGS. 7A and 7B .  FIGS. 8A and 8B  are enlarged views of an important part that corresponds to area Z 1  in  FIG. 3A . 
     In an example illustrated in  FIG. 7A , surface roughness of bottom surfaces  221  of enlarging depressions  22  is at least higher than surface roughness of contact portions  212  of bottom surface  211  of depression  21 . That is to say, bottom surfaces  221  of enlarging depressions  22  are at least rougher than contact portions  212  of bottom surface  211  of depression  21 . More specifically, bottom surfaces  221  of enlarging depressions  22  are processed by knurling or embossing, for example. Consequently, surface roughness of bottom surfaces  221  of enlarging depressions  22  is higher than surface roughness of bottom surface  211  of depression  21 . Consequently, scraped powder P 1  that has moved from depression  21  into enlarging depressions  22  is captured by bottom surfaces  221  of enlarging depressions  22 . Therefore, scraped powder P 1  is more likely to stay in enlarging depressions  22 . Consequently, scraped powder P 1  is less likely to move from enlarging depressions  22  into depression  21 . 
     A top surface of part of metal component  92  exposed by the bottom surface of depression  21  of case  2  forms part of bottom surface  211  of depression  21 , as illustrated in  FIGS. 7A and 7B . A top surface of part of metal component  92  exposed by the bottom surfaces of enlarging depressions  22  of case  2  forms part of bottom surfaces  221  of enlarging depressions  22 , as illustrated in  FIGS. 7A and 7B . 
     In an example illustrated in  FIG. 7B , depth D 2  of enlarging depressions  22  is at least larger than depth D 1  of depression  21  at contact portions  212  (D 2 &gt;D 1 ). Depth D 2  of enlarging depressions  22  is a distance from top surface  23  of case  2  to bottom surfaces  221  of enlarging depressions  22 . Depth D 1  of depression  21  is a distance from top surface  23  of case  2  to bottom surface  211  of depression  21 . That is to say, bottom surfaces  221  of enlarging depressions  22  are at least lower than contact portions  212  of bottom surface  211  of depression  21 . Further, there is a step between bottom surface  221  of each of enlarging depressions  22  and corresponding one of contact portions  212  of bottom surface  211  of depression  21 . 
     That is to say, when enlarging depressions  22  and depression  21  are seen from above (seen in a first direction), bottom surfaces  221  of enlarging depressions  22  are lower than bottom surface  211  of depression  21  (contact portions  212 ) (bottom surfaces  221  of enlarging depressions  22  are more in a second direction than bottom surface  211  of depression  21  (contact portions  212 ) is in the second direction). 
     Consequently, scraped powder P 1  that has moved from depression  21  into enlarging depressions  22  is captured by bottom surfaces  221  of enlarging depressions  22 . Therefore, scraped powder P 1  is more likely to stay in enlarging depressions  22 . Consequently, scraped powder P 1  is less likely to move from enlarging depressions  22  into depression  21 . The configuration illustrated in  FIG. 7B  and the configuration illustrated in  FIG. 7A  may be combined and applied. 
     In an example illustrated in  FIG. 8A , case  2  has walls  25 A each of which is between each of enlarging depressions  22  and depression  21 . In an example illustrated in  FIG. 8B , case  2  has walls  25 B each of which is between each of enlarging depressions  22  and depression  21 . In the example in  FIG. 8A , the pair of walls  25 A protrude from a pair of side surfaces  222 , respectively. Further, the pair of walls  25 A protrude toward each other. Similarly, in the example in  FIG. 8B , the pair of walls  25 B protrude from a pair of side surfaces  222 , respectively. Further, the pair of walls  25 B protrude toward each other. Especially in the example in  FIG. 8B , the pair of walls  25 B diagonally protrude from the pair of side surfaces  222  toward an inside of corresponding one of enlarging depressions  22 , in a top view. Walls  25 A,  25 B decrease an area of an opening facing depression  21 , of each of enlarging depressions  22 . Consequently, if scraped powder P 1  moves from depression  21  into enlarging depressions  22 , walls  25 A,  25 B regulate movement of scraped powder P 1  toward depression  21 . Therefore, scraped powder P 1  is more likely to stay in enlarging depressions  22 . Consequently, scraped powder P 1  is less likely to move from enlarging depressions  22  into depression  21 . Especially in a configuration in  FIG. 8B , the pair of walls  25 B diagonally protrude toward an inside of corresponding one of enlarging depressions  22 . Therefore, scraped powder P 1  is much less likely to move from enlarging depressions  22  into depression  21 . 
     Walls  25 A are not necessarily in pairs. Further, walls  25 B are not necessarily in pairs. 
     (2.4) Stationary Contact 
     Hereinafter, (first) stationary contact  7  will be described in detail with reference to  FIGS. 9 to 10C .  FIG. 10B  is an enlarged view of area Z 1  in FIG. 
       10 A.  FIG. 10C  is an enlarged view of area Z 1  in  FIG. 10B .  FIGS. 10B and 10C  are cross-sectional views that each schematically illustrate only stationary contact  7 . Therefore, various dimensional relations (e.g., a thickness of base material  71  and a thickness of conductive layer  72 ) in  FIGS. 10B and 10C  are different from actual dimensional relations. 
     Stationary contact  7  includes base material  71  (see  FIG. 10B ) and conductive layer  72  (see  FIG. 10B ) that covers base material  71 . In the present exemplary embodiment, conductive layer  72  covers a whole top surface (contact surface  73 ) of base material  71 . Base material  71  is a copper alloy, such as phosphor bronze. Conductive layer  72  is a plated layer. Conductive layer  72  includes silver (Ag), for example. For example, nickel (Ni) is plated on a surface of base material  71  made of phosphor bronze to make a plated base layer. Further, silver (Ag) is plated on the plated base layer to make a plated silver layer. In that case, conductive layer  72  includes the plated base layer, and the plated silver layer. 
     Stationary contact  7  has contact surface  73  (a top surface in the present exemplary embodiment) that is opposite movable contact  8 . Movable contact  8  is disposed opposite contact surface  73  of stationary contact  7 . Movable contact  8  moves between a closed position (first position) where movable contact  8  is in contact with contact surface  73  and an open position (second position) where movable contact  8  is apart from contact surface  73 . That is to say, contacts  4  are closed when movable contact  8  is at the closed position (first position) (see  FIG. 5B ). Alternatively, contacts  4  are open when movable contact  8  is at the open position (second position) (see  FIG. 5A ). 
     Stationary contact  7  has protrusion  70  that protrudes from a base surface. Contact surface  73  is a surface of an end of protrusion  70 , as illustrated in  FIG. 9 . The base surface is bottom surface  211  of depression  21 . Protrusion  70  protrudes upward from bottom surface  211 . Protrusion  70  is substantially circular, in a top view. That is to say, contact surface  73  is a top surface of protrusion  70  that protrudes upward from a top surface of first metal component  91 . Further, protrusion  70  is substantially circular, in a top view. 
     Stationary contact  7  has grooves  74  that divide contact surface  73  into a plurality of areas  731 . Grooves  74  include first groove  741  and second groove  742 . First groove  741  and second groove  742  extend in different directions in a plane that is along contact surface  73 . First groove  741  intersects with second groove  742  at substantially a center of contact surface  73 . In  FIG. 9 , first groove  741  is a straight groove that extends forward right diagonally, in a top view. Further, second groove  742  is a straight groove that extends backward right diagonally, in a top view. First groove  741  intersects with second groove  742  substantially at a right angle. Consequently, grooves  74  have a shape like a cross. In the present exemplary embodiment, first groove  741  and second groove  742  that intersect with each other divide contact surface  73  into four areas  731 . Preferably, a width of grooves  74  is larger than a depth of grooves  74 . Preferably, a depth of grooves  74  is smaller than or equal to half (½) of a thickness of stationary contact  7  (first metal component  91 ). 
     Since grooves  74  divide contact surface  73  into the plurality of areas  731 , a structure-for-contact-at-a-plurality-of-positions is made for contacts  4 . The structure-for-contact-at-a-plurality-of-positions allows movable contact  8  to be in contact with a plurality of positions of stationary contact  7 , as described above. Therefore, even if foreign matter enters between stationary contact  7  and movable contact  8 , electrical properties of push switch  1  are less likely to deteriorate, compared with a case in which contact surface  73  of stationary contact  7  is one flat plane. Consequently, electrical properties of push switch  1  are less likely to vary. Therefore, reliability of contact increases. 
     If contacts  4  have the above structure-for-contact-at-a-plurality-of-positions, part of conductive layer  72  is likely to be removed from base material  71  of stationary contact  7  when excessive force is applied to movable component  3 , for example. Further, the more times push switch  1  is used, the more likely conductive layer  72  is to be removed. A conceivable cause is damage to conductive layer  72  at opening edges  751  of grooves  74 . Another conceivable cause is a stress concentration that occurs at opening edges  751  of grooves  74  when movable contact  8  is pushed against stationary contact  7 . Especially if movable contact  8  is more tightly plated than stationary contact  7  is plated, part of conductive layer  72  (a plated layer) of stationary contact  7  adheres to movable contact  8 . Consequently, part of conductive layer  72  is likely to be removed. For example, movable contact  8  is tightly plated if nickel (Ni) and copper are plated on a surface of a base material that is stainless steel (SUS) to make a plated base layer, and silver (Ag) is plated on the plated base layer to make a plated silver layer. If part of conductive layer  72  is removed, electrical properties of push switch  1  may vary. 
     As a countermeasure against such removal of conductive layer  72 , push switch  1  according to the present exemplary embodiment includes stationary contact  7  configured as described below. That is to say, in the present exemplary embodiment, each of grooves  74  has connection surfaces  753  that connect respective opening edges  751  of each of grooves  74  with bottom  752  of each of grooves  74 . Each of connection surfaces  753  has slope  754 , as illustrated in  FIGS. 10A to 10C . Each of slopes  754  is inclined at acute angles θ relative to contact surface  73  (see  FIG. 10C ). In the present disclosure, the “opening edges” are edges of an opening surface of each of grooves  74 . Further, each of the “opening edges” is a boundary between contact surface  73  and each of grooves  74 . Further, in the present disclosure, the “bottom” is a deepest portion in each of grooves  74 . That is to say, the “bottom” is a lowest portion in each of grooves  74 . Further, in the present disclosure, an “acute angle” is an angle that is larger than 0° and smaller than a right angle (90°). 
     In short, stationary contact  7  has connection surfaces  753  in grooves  74 . Connection surfaces  753  connect respective opening edges  751  with bottom  752 . In an example in  FIG. 10B , bottom  752  of groove  74  is flat. Further, each of connection surfaces  753  is a curved surface that is curved in such a manner that the curved surface protrudes toward an inside of corresponding one of grooves  74 . In other words, a corner between contact surface  73  and an inner surface of each of grooves  74  is rounded in an example in  FIG. 10B . Each of connection surfaces  753  that has such a shape has a curved surface that has slope  754 . Especially in the example in  FIG. 10B , whole connection surfaces  753  are curved surfaces. Therefore, whole connection surfaces  753  are inclined at acute angles relative to contact surface  73 . That is to say, whole connection surfaces  753  form slopes  754 . Consequently, the farther from opening edges  751  toward a center of a width of each of grooves  74 , the deeper a depth of each of grooves  74  becomes. 
     Further, in the present exemplary embodiment, each of connection surfaces  753  has slope  754  also at each of corners  76  at a point of intersection between first groove  741  and second groove  742  (see  FIG. 12A ). That is to say, each of connection surfaces  753  has slope  754  at least at each of corners  76  at the point of intersection between first groove  741  and second groove  742 . In the present exemplary embodiment, there are two pairs of corners  76  at the point of intersection between first groove  741  and second groove  742 . That is to say, there are four corners  76  at the point of intersection between first groove  741  and second groove  742 . Each of the two pairs of corners  76  are opposite each other. Two of four corners  76  are vertically opposite each other. The two other ones of four corners  76  are laterally opposite each other. At each of four corners  76 , each of connection surfaces  753  is a curved surface that is curved in such a manner that the curved surface protrudes toward an inside of grooves  74 . Especially in the present exemplary embodiment, at each of corners  76 , each of connection surfaces  753  is a curved surface that is curved in such a manner that the curved surface protrudes toward an inside of grooves  74 , at least in a plane that is along contact surface  73  (that is to say, in a plan view). Therefore, connection surfaces  753  have respective slopes  754  at any one of four corners  76 . Further, since four corners  76  each have slope  754 , areas of movable contact  8  that are in contact with four corners  76 , respectively, are not points. That is to say, areas of movable contact  8  that are in contact with four areas  731  of stationary contact  7 , respectively, are surfaces. Therefore, stationary contact  7  does not locally apply a large load to movable contact  8 . Therefore, occurrences of a stress concentration at movable contact  8  are also reduced. 
     Conductive layer  72  includes first conductive layer  721  and second conductive layer  722 , as illustrated in  FIG. 10C . First conductive layer  721  is part of conductive layer  72  and is at contact surface  73 . Second conductive layer  722  is part of conductive layer  72  and is at connection surfaces  753 . Preferably, first conductive layer  721  is connected with second conductive layer  722 . That is to say, if each of connection surfaces  753  is a curved surface that is curved in such a manner that the curved surface protrudes toward an inside of corresponding one of grooves  74 , as in the present exemplary embodiment, there is no step at each of opening edges  751  of grooves  74 . Therefore, in a method for manufacturing stationary contact  7  described later, damage is less likely to occur between first conductive layer  721  and second conductive layer  722  at each of opening edges  751 . Therefore, first conductive layer  721  and second conductive layer  722  that are connected with each other are easily made. 
     In push switch  1  according to the present exemplary embodiment, the above configuration allows conductive layer  72  to be less likely to be damaged at opening edges  751  of grooves  74 . Further, the above configuration allows a stress concentration to be less likely to occur at opening edges  751  of grooves  74  when movable contact  8  is pushed against stationary contact  7 . Therefore, even if several tens of newtons are applied to movable component  3  of push switch  1  according to the present exemplary embodiment, for example, conductive layer  72  is less likely to be removed from base material  71 . Further, even if push switch  1  is used several million times to several ten million times, conductive layer  72  is less likely to be removed from base material  71 . 
     Next, an example of methods for manufacturing stationary contact  7  configured as described above will be described with reference to  FIGS. 11A to 11C . 
     In the present exemplary embodiment, first, in a plating step, conductive layer  72  is plated on a surface of base material  71  to make metal sheet  100  that will become first metal component  91 . Then, in a first pressing step, metal sheet  100  that includes conductive layer  72  is pressed to make grooves  74 , as illustrated in  FIGS. 11A and 11B . In the first pressing step, metal sheet  100  is disposed on pad Y 3 , and then metal sheet  100  is pressed from above with punch Y 2  that has a shape like a cross. Consequently, metal sheet  101  that has grooves  74  is made. 
     Then, in a second pressing step, metal sheet  101  is pressed to make protrusion  70 , as illustrated in  FIG. 11C . In the second pressing step, metal sheet  101  is pressed upward with punch Y 4  that is cylindrical while a top surface of metal sheet  101  is pushed with die Y 5  that is cylindrical. Consequently, first metal component  91  that has protrusion  70  is made. 
     Second conductive layer  722  (see  FIG. 10C ) is part of conductive layer  72  and is at connection surfaces  753 . Second conductive layer  722  is stretched in the first pressing step of the above manufacturing method. Therefore, a thickness of second conductive layer  722  is smaller than a thickness of first conductive layer  721  (see  FIG. 10C ). That is to say, a thickness of first conductive layer  721  may be different from a thickness of second conductive layer  722 . 
     The above manufacturing method is only an example. For example, after the first pressing step and the second pressing step, the plating step is performed to plate conductive layer  72  on a surface of base material  71 . That is to say, the first pressing step, the second pressing step, and the plating step may be performed in this order. In the above manufacturing method, before the first pressing step, a metal sheet is blanked to form an outer shape of metal sheet  100  that will become first metal component  91 . However, after the second pressing step, a metal sheet may be blanked to form an outer shape of first metal component  91 , for example. 
     (2.5) Shapes of Corners of Stationary Contact 
     Next, shapes of each of corners  76  formed at a point of intersection between first groove  741  and second groove  742  in stationary contact  7  will be described in detail with reference to  FIGS. 12A to 15 . In an example described below, four corners  76  at a point of intersection between first groove  741  and second groove  742  have a same shape. Therefore, one corner  76  of four corners  76  will be described. 
     In an example illustrated in  FIGS. 12A to 12C , a first shape is used as a shape for corners  76  at a point of intersection between first groove  741  and second groove  742 . In an example illustrated in  FIGS. 13A to 13C , a second shape is used as a shape for corners  76  at a point of intersection between first groove  741  and second groove  742 . A difference between the first shape and the second shape is a relation between radius-of-curvature-in-a-plan-view Rxy that is a radius of curvature of corner  76 , in a top view (see  FIG. 12B ) and radius-of-curvature-in-a-cross-sectional-view Rz that is a radius of curvature of corner  76 , in a cross-sectional view (see  FIG. 12C ). In the present disclosure, radius-of-curvature-in-a-plan-view Rxy is a radius of curvature of corner  76 , in a plane that is along contact surface  73 . In an example in  FIG. 12B , radius-of-curvature-in-a-plan-view Rxy is a radius of curvature of corner  76 , in a plane of bottom  752  of grooves  74 . In the present disclosure, radius-of-curvature-in-a-cross-sectional-view Rz is a radius of curvature of corner  76 , in a plane that is perpendicular to contact surface  73 . In an example in  FIG. 12C , radius-of-curvature-in-a-cross-sectional-view Rz is a radius of curvature of corner  76 , in a cross-sectional view taken along line X 1 -X 1  in  FIG. 12B . 
     A difference in a shape of each of corners  76  varies a stress that acts on movable contact  8  when movable contact  8  is pushed against stationary contact  7 . A stress that acts on movable contact  8  in a case where radius-of-curvature-in-a-plan-view Rxy is larger than radius-of-curvature-in-a-cross-sectional-view Rz is especially smaller than a stress that acts on movable contact  8  in a case where radius-of-curvature-in-a-plan-view Rxy is smaller than radius-of-curvature-in-a-cross-sectional-view Rz. In the first shape illustrated in  FIGS. 12A to 12C , radius-of-curvature-in-a-plan-view Rxy is larger than radius-of-curvature-in-a-cross-sectional-view Rz. Therefore, a relational expression “Rxy&gt;Rz” is satisfied. On the other hand, in the second shape illustrated in  FIGS. 13A to 13C , radius-of-curvature-in-a-plan-view Rxy is smaller than radius-of-curvature-in-a-cross-sectional-view Rz. Therefore, a relational expression “Rxy&lt;Rz” is satisfied. That is to say, preferably, radius-of-curvature-in-a-plan-view Rxy is larger than radius-of-curvature-in-a-cross-sectional-view Rz, as in the first shape, to reduce a stress that acts on movable contact  8  when movable contact  8  is pushed against stationary contact  7 . 
       FIG. 14A  is a schematic view that illustrates contact areas A 1  at corners  76  that each have the first shape. Contact areas A 1  are areas of stationary contact  7 . Movable contact  8  comes into contact with contact areas A 1  when movable contact  8  is pushed against stationary contact  7 .  FIG. 14B  is a schematic view that illustrates contact areas A 1  at corners  76  that each have the second shape. Contact areas A 1  are areas of stationary contact  7 . Movable contact  8  comes into contact with contact areas A 1  when movable contact  8  is pushed against stationary contact  7 . As clearly illustrated in  FIGS. 14A and 14B , a shape and an area of each of contact areas A 1  with which movable contact  8  comes into contact vary due to a shape of each of corners  76  at a point of intersection between first groove  741  and second groove  742 . For example, in the first shape illustrated in  FIG. 14A , each of contact areas A 1  is a “laterally long” area that extends along opening edge  751  of corresponding one of grooves  74 , in a plane that is along contact surface  73 . On the other hand, in the second shape illustrated in  FIG. 14B , each of contact areas A 1  is a “vertically long” area that extends perpendicularly to opening edge  751  of corresponding one of grooves  74 . Each of contact areas A 1  of the first shape is larger than each of contact areas A 1  of the second shape. Consequently, the first shape that satisfies the relational expression “Rxy&gt;Rz” reduces occurrences of a stress concentration at movable contact  8 , compared with the second shape that satisfies the relational expression “Rxy&lt;Rz”. Therefore, the first shape reduces a stress that acts on movable contact  8 . 
       FIG. 15  is a graph that illustrates a relation between a shape of each of corners  76  and magnitude of a stress that acts on movable contact  8  when movable contact  8  is pushed against stationary contact  7 . In  FIG. 15 , a horizontal axis represents a length of radius-of-curvature-in-a-plan-view Rxy, and a vertical axis represents a stress that acts on movable contact  8  (a maximum von Mises stress). Further, in  FIG. 15 , “G 1 ” is assigned to a line that represents a case in which radius-of-curvature-in-a-cross-sectional-view Rz is “0.03 mm”. Further, in  FIG. 15 , “G 2 ” is assigned to a line of a comparative example that represents a case in which radius-of-curvature-in-a-cross-sectional-view Rz is “0.00 mm” Suppose that, in either case, magnitude of a load that pushes movable contact  8  against stationary contact  7  is “13 N”, and a width of each of grooves  74  (a distance between opening edges  751  of first groove  741 , or a distance between opening edges  751  of second groove  742 ) is “0.09 mm”. 
     Criterion value F 1  is a stress in a case where radius-of-curvature-in-a-cross-sectional-view Rz is “0.00 mm”, and radius-of-curvature-in-a-plan-view Rxy is “0.00 mm” (a point on line G 2  at which a value represented by the horizontal axis is “0.00”). That is to say, criterion value F 1  is a stress in a case where corners  76  are not curved surfaces. As clearly represented by graph G 1  in  FIG. 15 , it is expected that a stress is smaller than criterion value F 1  if radius-of-curvature-in-a-cross-sectional-view Rz is “0.03 mm” and radius-of-curvature-in-a-plan-view Rxy is larger than radius-of-curvature-in-a-cross-sectional-view Rz (Rxy&gt;Rz). In an example in  FIG. 15 , a stress that is substantially equal to criterion value F 1  acts on movable contact  8  when radius-of-curvature-in-a-cross-sectional-view Rz is “0.03 mm” and radius-of-curvature-in-a-plan-view Rxy is substantially equal to an upper limit of “0.2 mm” that has been determined. Therefore, if, in the example, radius-of-curvature-in-a-cross-sectional-view Rz is “0.03 mm”, a stress is smaller than criterion value F 1 , in a range of radius-of-curvature-in-a-plan-view Rxy that is 0.03 mm&lt;Rxy&lt;0.2 mm (the upper limit). A shape of each of corners  76  is adjusted within the range. Consequently, a stress becomes smaller than criterion value F 1  by at most approximately 40%. 
     If radius-of-curvature-in-a-plan-view Rxy is equal to radius-of-curvature-in-a-cross-sectional-view Rz (Rxy=Rz), a stress hardly becomes smaller than criterion value F 1 . A conceivable reason that a stress hardly becomes smaller than criterion value F 1  is, for example, that a surface of each of corners  76  becomes part of a surface of a sphere. Consequently, areas of movable contact  8  that are in contact with corners  76 , respectively, are almost points. Further, if radius-of-curvature-in-a-plan-view Rxy is larger than or equal to the upper limit (“0.2 mm” in the example in  FIG. 15 ), a stress hardly become smaller than criterion value F 1 . A conceivable reason that a stress hardly becomes smaller than criterion value F 1  is, for example, that a distance between a pair of corners  76  that are opposite each other is excessive. That is to say, if a distance between a pair of corners  76  that are opposite each other is excessive, movable contact  8  is more likely to be bent between the pair of corners  76 . Therefore, a larger moment about one of the pair of corners  76  acts on movable contact  8 . Consequently, corners  76  apply a larger stress to movable contact  8 . Therefore, the stress hardly becomes smaller than criterion value F 1 . 
     As described above, magnitude of a stress that acts on movable contact  8  is adjusted for push switch  1  according to the present exemplary embodiment. The stress acts on movable contact  8  when movable contact  8  is pushed against stationary contact  7 . The magnitude of a stress that acts on movable contact  8  is adjusted by a shape of corners  76  of stationary contact  7 . Especially when radius-of-curvature-in-a-plan-view Rxy is larger than radius-of-curvature-in-a-cross-sectional-view Rz, a stress that acts on movable contact  8  is small. However, above radius-of-curvature-in-a-plan-view Rxy, above radius-of-curvature-in-a-cross-sectional-view Rz, and above dimensions, such as a width, of grooves  74  are only examples and may be appropriately changed. Radius-of-curvature-in-a-cross-sectional-view Rz is not limited to “0.03 mm”, but may be “0.05 mm”, for example. A configuration that reduces a stress that acts on movable contact  8  has been described above. The configuration reduces a stress that acts on conductive layer  72  of stationary contact  7 . Consequently, electrical properties of push switch  1  are less likely to vary. Conductive layer  72  is a plated layer, for example. 
     (2.6) Direction of Rolling 
     In push switch  1  according to the present exemplary embodiment, a direction of rolling of movable component  3  intersects with directions in which grooves  74  (first groove  741  and second groove  742 ) extend, as illustrated in  FIG. 16 . In  FIG. 16 , arrows that point right schematically represent a direction of rolling R of movable component  3 . 
     In the present disclosure, the “direction of rolling” is a direction in which a metal sheet that will become movable component  3  is rolled at a time of a manufacturing process. That is to say, if a process for manufacturing a metal sheet that becomes movable component  3  includes a step that rolls a metal sheet, a direction in which the metal sheet is rolled in the step is the direction of rolling. If a bending line is generated in a metal sheet and the bending line is along a direction of rolling R, durability of the metal sheet deteriorates, compared with a case in which a bending line is generated in a metal sheet and a direction of the bending line intersects with the direction of rolling. 
     In the present exemplary embodiment, first groove  741  is a straight groove that extends forward right diagonally, in a top view. Further, second groove  742  is a straight groove that extends backward right diagonally, in a top view, as described above. A direction of rolling R of movable component  3  is lateral. Therefore, the direction of rolling of movable component  3  intersects with both a direction in which first groove  741  extends and a direction in which second groove  742  extends. 
     The above configuration improves durability of movable component  3 . That is to say, when movable contact  8  is pushed against stationary contact  7 , opening edges  751  of grooves  74  (first groove  741  and second groove  742 ) apply reaction force to movable component  3 . The reaction force generates a bending line in movable component  3 . However, the bending line intersects with a direction of rolling R of movable component  3 . Consequently, durability of movable component  3  is improved, compared with a case in which a bending line is generated in movable component  3  and the bending line is parallel to a direction of rolling R of movable component  3 . 
     (2.7) Other Examples of Stationary Contact 
     Push switch  1  may include stationary contact  7  configured as exemplified in  FIGS. 17A to 18C .  FIGS. 17A to 17C  are enlarged views of an important part that corresponds to area Z 1  in  FIG. 10A .  FIGS. 17A to 17C  are cross-sectional views that each schematically illustrate only stationary contact  7 . Therefore, various dimensional relations (e.g., a thickness of base material  71  and a thickness of conductive layer  72 ) in  FIGS. 17A to 17C  are different from actual dimensional relations. Further,  FIGS. 18A to 18C  are enlarged views of an important part that corresponds to area Z 2  in  FIG. 3A . 
     In an example illustrated in  FIG. 17A , slopes  754  of connection surfaces  753  are planes. More specifically, each of connection surfaces  753  has inner side surface  755  and tapered surface  756 . Inner side surface  755  is a plane that extends upward from each of ends of a width of bottom  752  of each of grooves  74 . Inner side surface  755  is perpendicular to contact surface  73 . Tapered surface  756  is an inclined plane. Consequently, the closer to a top of each of grooves  74  (an opening surface), the larger a width of each of grooves  74 . Consequently, whole tapered surface  756  of each of connection surfaces  753  is inclined at an acute angle relative to contact surface  73 . Therefore, whole tapered surface  756  is slope  754 . 
     Further, in an example illustrated in  FIG. 17B , slopes  754  of connection surfaces  753  are planes, similarly as in  FIG. 17A . More specifically, each of connection surfaces  753  has tapered surface  756 . Tapered surface  756  is a plane that extends upward diagonally from bottom  752  of each of grooves  74 . Further, tapered surface  756  is inclined. Consequently, the closer to a top of each of grooves  74  (an opening surface), the larger a width of each of grooves  74 . Consequently, whole tapered surface  756  of each of connection surfaces  753  is inclined at an acute angle relative to contact surface  73 . Therefore, whole tapered surface  756  is slope  754 . 
     Further, in an example illustrated in  FIG. 17C , slopes  754  are surfaces curved in such a manner that a width of bottom  752  of each of grooves  74  becomes narrower toward a lowest portion of bottom  752 . Consequently, a substantially whole inner surface of each of grooves  74  is a curved surface. 
     In an example illustrated in  FIG. 18A , groove  74  is one straight groove. More specifically, groove  74  is straight and laterally extends through substantially a center of contact surface  73 . Groove  74  divides contact surface  73  into two areas  731 . 
     In an example illustrated in  FIG. 18B , grooves  74  include three grooves  743 ,  744 ,  745 . Three grooves  743 ,  744 ,  745  extend in different directions in a plane that is along contact surface  73 . Three grooves  743 ,  744 ,  745  are straight and extend radially from substantially a center of contact surface  73 . Two grooves of three grooves  743 ,  744 ,  745  correspond to the “first groove” and the “second groove”. Grooves  74  divide contact surface  73  into three areas  731 . 
     In an example illustrated in  FIG. 18C , grooves  74  include four grooves  746 ,  747 ,  748 ,  749 . Groove  746  is straight and vertically extends through substantially a center of contact surface  73 . Three grooves  747 ,  748 ,  749  are each straight and laterally extend. Three grooves  747 ,  748 ,  749  are vertically arranged at regular intervals. Therefore, three grooves  747 ,  748 ,  749  are each substantially perpendicular to groove  746 . Groove  746  and one of three grooves  747 ,  748 ,  749  correspond to the “first groove” and the “second groove”. Grooves  74  divide contact surface  73  into eight areas  731 . 
     (3) Examples of Modifications 
     The above present exemplary embodiment is merely one of various exemplary embodiments of the present disclosure. The exemplary embodiment is variously modified according to design as long as an object of the present disclosure is fulfilled. Hereinafter, some examples of modifications of the exemplary embodiment will be recited. Some or all of the examples of modifications described later are appropriately combined and applied. 
     A shape of an opening of depression  21  of push switch  1  is not only like an ellipse whose lateral length is longer than a vertical length of the ellipse, in a top view, but also may be like a rectangle, a circle, or a polygon. In case of the configuration, shapes of movable component  3  and other components are determined according to a shape of an opening of depression  21 . 
       FIG. 19A  illustrates push switch  1 A according to a first example of modifications of the exemplary embodiment. In push switch  1 A according to the first example of modifications, movable component  3  has main body  31  and a plurality of (four in the first example of modifications) legs  32 . Main body  31  has a shape like an ellipse whose lateral length is longer than a vertical length of the ellipse, in a top view, similarly as movable component  3  in the above exemplary embodiment. Four legs  32  protrude from a periphery of main body  31 . Four legs  32  are arranged at predetermined intervals along the periphery of main body  31 . Four legs  32  are each substantially rectangular. Four legs  32  are connected with main body  31 . Movable component  3  is disposed in depression  21 . An orientation of each of the plurality of legs  32  corresponds to corresponding one of a plurality of enlarging depressions  22 . In the configuration of the first example of modifications, four legs  32  protrude from main body  31 . Therefore, four legs  32  increase a distance from movable contact  8  to stationary contact  7 . Therefore, a length of a stroke becomes longer. 
       FIG. 19B  illustrates push switch  1 B according to a second example of modifications of the exemplary embodiment. In push switch  1 B according to the second example of modifications, movable component  3  has main body  31  and a plurality of (four in the second example of modifications) legs  32 , similarly as the first example of modifications. In the second example of modifications, main body  31  is substantially circular, in a top view. 
     As another example of modifications, a length of a stroke of push switch  1  may be appropriately changed. The length of a stroke of push switch  1  is an amount of movement of protective sheet  5  through an operational area at a time when push switch  1  is pushed to close push switch  1 . The length of a stroke of push switch  1  may be relatively short, medium, or relatively long, for example. The medium length is between the relatively short length and the relatively long length. Further, push switch  1  may include first contacts and second contacts, instead of contacts  4 . In case of push switch  1  that includes the first contacts and the second contacts, when protective sheet  5  is pushed, the first contacts are closed first. If protective sheet  5  is further pushed while the first contacts are closed, the second contacts are closed. In case of push switch  1  that includes the first contacts and the second contacts, movable component  3  may include two metal sheets that are buckled by different operational force. Further, push switch  1  is not necessarily normally open. Push switch  1  may be normally closed. Push switch  1  that is normally closed is opened when push switch  1  is operated. 
     Further, push switch  1  is not only used as one of controls of a device operated by a person, but also may be used as a detector for a device. If push switch  1  is used as a detector for a device, push switch  1  is used, for example, as a limit switch to detect a position of a component of a machine, such as an actuator. 
     Further, movable component  3  does not necessarily include a plurality of leaf springs  30  stacked together. Movable component  3  may include one leaf spring. Further, movable component  3  does not necessarily include three leaf springs  30 . Movable component  3  may include two leaf springs  30 , or four or more leaf springs  30 . In that case, a number of leaf springs  30  stacked together varies operational force required to buckle movable component  3 . Consequently, the number of leaf springs  30  stacked together varies tactility of push switch  1 . 
     Pressing component  6  is not necessarily disposed between protective sheet  5  and pressure receiving portion  33 . Pressing component  6  may be disposed on a top surface of protective sheet  5 , for example. In that case, an underside of pressing component  6  may be joined to a top surface of protective sheet  5 . In the configuration, protective sheet  5  transfers operational force that acts on pressing component  6  to pressure receiving portion  33 . 
     Further, protective sheet  5  only needs to cover at least part of depression  21 . Protective sheet  5  that covers whole depression  21  is not essential to push switch  1 . For example, a hole may be made through part of protective sheet  5 . Push switch  1  may not include protective sheet  5 . 
     Further, a conductive film is not necessarily made on a whole underside of movable component  3 . For example, a conductive film may be made on part of an underside of movable component  3  with which stationary contact  7  is in contact, and on part of the underside of movable component  3  with which stationary contact  921  is in contact. Further, a conductive film may not be appropriately made on an underside of movable component  3 . In that case, preferably, part or all of movable component  3  is made of a conductive material. Consequently, movable component  3  is surely conductive. 
     Retaining pins Y 1  retain one of metal components  9  when case  2  is molded. Retaining pins Y 1  are not necessarily in contact with an underside of the one of metal components  9  (stationary contact  921 ). Retaining pins Y 1  may be in contact with a top surface of the one of metal components  9 . In that case, pin receiving portions  93  are on the top surface of the one of metal components  9 . Further, even if retaining pins Y 1  are in contact with an underside of the one of metal components  9 , pin holes  24  made through an underside of case  2  may be filled with a synthetic resin after case  2  has been molded. 
     Conductive layer  72  is not limited to a plated layer. Conductive layer  72  may be a painted film or a film, for example. If conductive layer  72  is a film, conductive layer  72  is stuck to base material  71 . 
     Grooves  74  of stationary contact  7  are not necessarily complete hollows. A synthetic resin of which case  2  is made may exist in grooves  74  of stationary contact  7 . That is to say, a synthetic resin may fill at least part of grooves  74  of stationary contact  7 . 
     (4) Conclusion 
     As described above, a first aspect of push switch ( 1 ,  1 A,  1 B) includes stationary contact ( 7 ) and movable contact ( 8 ). Stationary contact ( 7 ) includes base material ( 71 ) and conductive layer ( 72 ) that covers base material ( 71 ). Movable contact ( 8 ) is disposed opposite contact surface ( 73 ) of stationary contact ( 7 ). Movable contact  8  moves between a first position (closed position) where movable contact ( 8 ) is in contact with contact surface ( 73 ) and a second position (open position) where movable contact ( 8 ) is apart from contact surface ( 73 ). Stationary contact ( 7 ) has groove ( 74 ) that divides contact surface ( 73 ) into a plurality of areas ( 731 ). Connection surfaces ( 753 ) connect respective opening edges ( 751 ) of groove ( 74 ) with bottom ( 752 ) of groove ( 74 ). Each of connection surfaces ( 753 ) has slope ( 754 ). Slope ( 754 ) is inclined at acute angle (θ) relative to contact surface ( 73 ). 
     According to the first aspect, groove ( 74 ) divides contact surface ( 73 ) into the plurality of areas ( 731 ). Therefore, a structure-for-contact-at-a-plurality-of-positions is made. The structure-for-contact-at-a-plurality-of-positions allows movable contact ( 8 ) to be in contact with a plurality of positions of stationary contact ( 7 ). Therefore, even if foreign matter enters between stationary contact ( 7 ) and movable contact ( 8 ), electrical properties of push switch ( 1 ) are less likely to deteriorate, compared with a case in which contact surface ( 73 ) of stationary contact ( 7 ) is one flat plane. Further, connection surfaces ( 753 ) connect respective opening edges ( 751 ) of groove ( 74 ) with bottom ( 752 ) of groove ( 74 ). Each of connection surfaces ( 753 ) has slope ( 754 ). Slope ( 754 ) is inclined at acute angle (θ) relative to contact surface ( 73 ). Therefore, conductive layer ( 72 ) is less likely to be damaged at opening edges ( 751 ) of groove ( 74 ). Further, a stress concentration is less likely to occur at opening edges ( 751 ) of groove ( 74 ) when movable contact ( 8 ) is pushed against stationary contact ( 7 ). Consequently, conductive layer ( 72 ) is less likely to be removed, and thus electrical properties of push switch  1  are less likely to vary though push switch  1  has the structure-for-contact-at-a-plurality-of-positions. 
     A second aspect of push switch ( 1 ,  1 A,  1 B) is the first aspect in which slope ( 754 ) is a curved surface. 
     The second aspect allows a step to be less likely to be generated at opening edges ( 751 ) of groove ( 74 ). Therefore, conductive layer ( 72 ) is much less likely to be removed. 
     A third aspect of push switch ( 1 ,  1 A,  1 B) is the first aspect in which slope ( 754 ) is a plane. 
     The third aspect simplifies a shape of groove ( 74 ). 
     In a fourth aspect of push switch ( 1 ,  1 A,  1 B), groove ( 74 ) includes first groove ( 741 ) and second groove ( 742 ) that extend in different directions in a plane that is along contact surface ( 73 ). Each of connection surfaces ( 753 ) has slope ( 754 ) at least at each of corners at a point of intersection between first groove ( 741 ) and second groove ( 742 ). 
     The fourth aspect allows conductive layer ( 72 ) to be less likely to be damaged at the point of intersection between first groove ( 741 ) and second groove ( 742 ). Further, the fourth aspect allows a stress concentration to be less likely to occur when movable contact ( 8 ) is pushed against stationary contact ( 7 ). Therefore, conductive layer ( 72 ) is less likely to be removed at the point of intersection between first groove ( 741 ) and second groove ( 742 ). 
     In a fifth aspect of push switch ( 1 ,  1 A,  1 B), at each of corners ( 76 ), each of connection surfaces ( 753 ) is a curved surface that is curved in such a manner that the curved surface protrudes toward an inside of groove ( 74 ), at least in a plane that is along contact surface ( 73 ). 
     The fifth aspect allows a stress concentration to be less likely to occur when movable contact ( 8 ) is pushed against stationary contact ( 7 ). 
     In a sixth aspect of push switch ( 1 ,  1 A,  1 B), radius of curvature (Rxy) of each of corners ( 76 ) in a plane that is along contact surface ( 73 ) is smaller than a predetermined upper limit. 
     The sixth aspect allows a stress concentration to be less likely to occur when movable contact ( 8 ) is pushed against stationary contact ( 7 ). 
     In a seventh aspect of push switch ( 1 ,  1 A,  1 B), radius of curvature (Rxy) of each of corners ( 76 ) in a plane that is along contact surface ( 73 ) is larger than radius of curvature (Rz) of each of corners ( 76 ) in a plane that is perpendicular to contact surface ( 73 ). 
     The seventh aspect allows a stress concentration to be less likely to occur when movable contact ( 8 ) is pushed against stationary contact ( 7 ). 
     In an eighth aspect of push switch ( 1 ,  1 A,  1 B), conductive layer ( 72 ) is a plated layer. 
     The eighth aspect allows a thickness of conductive layer ( 72 ) is to be easily adjusted. 
     In a ninth aspect of push switch ( 1 ,  1 A,  1 B), stationary contact ( 7 ) has protrusion ( 70 ) that protrudes from a base surface. Contact surface ( 73 ) is a surface of an end of protrusion ( 70 ). 
     The ninth aspect suppresses movable contact ( 8 ) from being in contact with a portion other than contact surface ( 73 ). 
     A tenth aspect of push switch ( 1 ,  1 A,  1 B) is any one of the first to ninth aspects in which conductive layer ( 72 ) includes first conductive layer ( 721 ) on contact surface ( 73 ), and second conductive layer ( 722 ) on each of connection surfaces ( 753 ), first conductive layer ( 721 ) being connected with second conductive layers ( 722 ). 
     The tenth aspect allows conductive layer ( 72 ) to be less likely to be removed at a boundary between first conductive layer ( 721 ) and second conductive layer ( 722 ). 
     An eleventh aspect of push switch ( 1 ,  1 A,  1 B) is any one of the first to tenth aspects that further includes movable component ( 3 ) that has movable contact ( 8 ) on a surface of movable component ( 3 ). The surface of movable component ( 3 ) is opposite stationary contact ( 7 ). A direction of rolling R of movable component ( 3 ) intersects with a direction in which groove ( 74 ) extends. 
     The eleventh aspect improves durability of movable component ( 3 ), compared with a case in which the direction of rolling of movable component ( 3 ) is parallel to a direction in which groove ( 74 ) extends. 
     Configurations of the second to eleventh aspects are not essential to push switch ( 1 ,  1 A,  1 B). Therefore, push switch ( 1 ,  1 A,  1 B) may not appropriately include the configurations of the second to eleventh aspects. 
     REFERENCE MARKS IN THE DRAWINGS 
     
         
         
           
               1 ,  1 A,  1 B: push switch 
               2 : case 
               3 : movable component 
               4 : contacts 
               5 : protective sheet 
               6 : pressing component 
               7 : stationary contact 
               8 : movable contact 
               9 : metal component 
               11 ,  12 : terminal 
               21 : depression 
               22 : enlarging depression 
               23 : top surface 
               24 : pin hole 
               25 A,  25 B: wall 
               31 : main body 
               32 : leg 
               33 : pressure receiving portion 
               51 : joined-portion 
               70 : protrusion 
               71 : base material 
               72 : conductive layer 
               73 : contact surface 
               74 : groove 
               76 : corner 
               91 : metal component 
               92 : metal component 
               93 : pin receiving portion 
               100 ,  101 : metal sheet 
               211 : bottom surface 
               212 : contact portion 
               213   a ,  213   b : side surface 
               221 : bottom surface 
               222 : side surface 
               721 ,  722 : conductive layer 
               731 : area 
               741 ,  742 ,  743 ,  746 ,  747 ,  748 ,  749 : groove 
               751 : opening edge 
               752 : bottom 
               753 : connection surface 
               754 : slope 
               755 : inner side surface 
               756 : tapered surface 
               921 : stationary contact 
             D 1 : depth 
             D 2 : depth 
             L 1 : imaginary line 
             L 2 : imaginary line 
             P 1 : powder 
             Y 1 : retaining pin 
             Y 2 : punch 
             Y 3 : pad 
             Y 4 : punch 
             Y 5 : die 
             Z 1 : area 
             Z 2 : area 
             θ: angle of inclination 
             Rxy: radius-of-curvature-in-a-plan-view 
             Rz: radius-of-curvature-in-a-cross-sectional-view