Abstract: A push switch includes a case having a bottom face, first and second fixed contacts provided on the bottom face of the case, a movable contact made of metal thin plate, an elastic body, and an operating body. The elastic body includes a cylindrical portion having a hole formed therein, a conical portion provided below the cylindrical portion, a projection located above the movable contact, and a junction portion coupling the projection to the cylindrical portion. This push switch can provide a long over-stroke after being turned on.

Abstract: A switch integrated type housing includes a housing body, a switch button sheet, a conductor and a cover sheet. The housing body is provided with a plurality of concave sections on an outer surface of the housing body. The switch button sheet is provided on the outer surface to cover the plurality of concave sections. The conductor has a dome shape downwardly projecting and is provided in each of the plurality of concave sections to contact the switch button sheet. The cover sheet is provided between the switch button sheet and the outer surface of the housing body in a portion of the outer surface of the housing body other than the plurality of concave sections and to cover a lower surface of the conductor in each of the plurality of concave sections.

Abstract: A movable contact body includes a separator (13), a number of domes (12), an insulative film (11) and a shielding (10). The separator is made of insulative material and is substantially a planar sheet. The domes are made of resilient conductive material and are located on the separator in pre-determined locations. The insulative film coats on upper surfaces of the domes. The planar shielding is made of conductive material and coats on the insulative film. The planar shielding defines a number of openings (100) in predetermined locations corresponding to the domes. Each opening receives one dome therein.

Abstract: A switch sheet and switch utilizing the switch sheet are provided, wherein the switch sheet utilizes a dome shaped spring, and is structured such that the dome shaped spring can be definitively clicked in the center part and operate effectively even when the dome shaped spring is miniaturized. In addition to having long-lasting, superior durability, this switch sheet provides an improved click ratio enabling miniature devices with a good clicking sensation to be achieved. This switch sheet comprises a dome shaped spring, resin sheeting adhered to the external surface of this dome shaped spring via an adhesive agent, and a rigid member positioned on the outside of this resin sheeting, having a downward facing protrusion part formed to oppose the center part of said dome shaped spring.

Abstract: A two-step push-on switch sequentially operates first and second switches via a movable contact plate configured by a metal plate spring and fixed by an adhesive tape onto a circuit board. A spacer is placed around the movable contact plate. A continuous or discontinuous tape-sticking face is lower than the top of a center plate portion and higher than a peripheral plate portion due to the spacer around the movable contact plate, thereby preventing the tape from sticking to the peripheral plate portion. In the tape, non-adhesive portions are formed in places opposing to parts of the peripheral plate portion of the movable contact plate excluding at least the connecting portions with the connecting plate portions respectively. When the adhesive tap makes contact with the peripheral plate portion during operation of the first switch, the adhesive tape is prevented from sticking to the peripheral plate portion.

Abstract: A keypad for a mobile communication terminal is provided. The keypad includes a sheet having contacts which deflect so as to switch contact point pairs on a printed circuit board on and off. The contacts may be formed as hemispherical domes to facilitate use. The sheet may also include band parts covering the contacts and an insulting sheet having at least one pair of semicircular openings which expose portions of the contacts. The insulating sheet is preferably made of a light-reflecting material/color which disperses light to illuminate keys of the keypad.

Abstract: A first stationary contact (i.e., center stationary contact) has a center contact point exposed at the center on the bottom of a recess in a square-shaped switch base as viewed from the above. The first stationary contact is disposed to the bottom of the recess with its lead paths extended along one of diagonal lines of the square-shaped switch base from the center contact point toward both side edges of the switch base. Second stationary contacts (i.e., outer stationary contacts) are arranged at positions along an outer brim of the recess in a line-symmetrical manner about the one of the diagonal lines in areas opposite each other along the other diagonal line. The first stationary contact and the second stationary contacts are arranged in this manner and secured into embedment by means of insertion molding in the bottom of the recess in the switch base of an insulation resin.

Abstract: A printed circuit board is provided for use in a keyboard assembly of a mobile device having a plurality of keys in a key layout. The printed circuit board has a plurality of contacts, such as dome switches, arranged in a contact layout. The contact layout is such that it can be used with a plurality of different key layouts, each actuating different combinations of contacts. Some keys in a particular key layout are overlying at least two of the plurality of contacts, and such keys actuate only one of the underlying contacts. As such, a common printed circuit board can be used for a plurality of complementary mobile device designs having different key layouts, thereby allowing a manufacturer to realize cost efficiencies.

Abstract: An improved thin switch aims at reducing overall height of switches without shortening existing compression displacement. It has a trigger assembly which includes an upper button with a bracing section housed in a compartment, a coupling trough, and a lower button with compression section held in the coupling trough without exceeding the anchor portion of the coupling trough. The lower button further has a ram section located between the compression section and the elastic element. The upper button and lower buttons may be deformed as desired to reduce the overall height of the thin switch without affecting existing compression displacement.

Abstract: A two-step push-on switch in which the operating stroke of an upper movable contact is ensured, and particularly the width of the switch is reduced while the durability of the upper movable contact is improved, the number of parts is reduced, an the operation is improved. Dome-like movable contacts are placed in two or upper and lower stages in an invertible manner in a recess of an insulative body having a plurality of stationary contacts, and the upper movable contact is formed into an oval shape.

Abstract: The keysheet module has a flexible printed circuit board formed with dome-shaped depression switches on the upper surface thereof. Each of the depression switches comprises a first fixed contact, a second fixed contact surrounding the first fixed contact, a movable contact arranged over these fixed contacts to electrically connect and disconnect the first fixed contact and the second fixed contact, and a switch holding sheet arranged on the flexible printed circuit board to cover and hold the movable contact. An insulating film of an insulating paste is formed on the flexible printed circuit board in such a way that it has air holes formed therein to release air trapped in the movable contact. The switch holding sheet is arranged over the insulating film.

Abstract: A key sheet comprising a key top, a translucent resin film, and a symbol layer. The key top is made of resin and has a top surface and a rear surface. The key top includes a gate corresponding section in a position corresponded to a gate of a mold for injecting resin to form the key top. The translucent resin film is provided over the key top. The symbol layer is disposed to associate with the top surface of the key top. The gate corresponding section is located to prevent that gate corresponding section from being viewed through the symbol layer.

Abstract: The invention provides a movable contact for a two-step push-on switch which can realize an excellent sense and a long life period while decreasing the width, even on a flat stationary-contact forming surface of a printed circuit board, a flexible printed circuit board or the like, and also a two-step push-on switch. A movable contact has: a rectangular annular peripheral plate portion 2; an oval center plate portion 3 which is upward inflatingly curved; and a pair of connecting plate portions 4, 4 which connect an inner edge of the peripheral plate portion 2 to an outer edge of said center plate portion 3 on a center line X which is parallel to long side portions 2a, 2a of said peripheral plate portion 2. The movable contact is disposed on a flat stationary-contact forming surface of a printed circuit board, a flexible printed circuit board, or the like, and an adhesive tape 9 for fixing the movable contact is bonded from a side of the upper face, thereby configuring a push-on switch.

Abstract: A push switch includes a case made of insulating resin including a plate-like portion shaped substantially like a plate, a first fixed contact exposed at a first surface of the plate-like portion of the case, a second fixed contact exposed at the first surface of the plate-like portion of the case, and a movable contact which electrically connects and disconnects the first fixed contact to the second fixed contact. A first metal member including the first fixed contact further includes a first terminal exposed outside the case, and a first middle portion exposed at a second surface of the plate-like portion of the case, the first middle portion connecting the first fixed contact to the first terminal. A second metal member including the second fixed contact further includes a second terminal exposed outside the case, and a second middle portion for connecting the second fixed contact to the second terminal.

Abstract: A two-step switch, which may be minimized in radial direction and is suitable for PCB or FPC circuit board, has a first contact spring, having outer peripheral contacts in regular contact with first fixed contacts and having an inner contact inside the outer peripheral contacts and reversed by depressing, and a second contact spring, stacked on the first contact spring via an insulation sheet, having an outer peripheral contact in regular contact with a second fixed contact and having an inner contact inside of the outer peripheral contact and reversed by depressing. Through a first depressing, the inner contact of the first contact spring is reversed and in contact with the inner contact of the second contact spring, whereby a first electric circuit is actuated. Also through a second depressing, the inner contact of the second contact spring is reversed and in contact with the third fixed contact, whereby a second electric circuit is actuated.

Abstract: A push-button switch includes insulating member having a surface, first and second stationary contacts electrically isolated from each other and provided at the surface of the insulating substrate, and a movable contact. The movable contact includes an elastic metal base having a dome-shape and having a concave surface spaced from the first stationary contact and an outer rim mounted on the second stationary contact, a nickel plated layer provided on the concave surface of the elastic metal base and having a thickness ranging from 0.05 ?m to 0.5 ?m, a copper plated layer provided on the nickel plated layer and having a thickness ranging from 0.05 ?m to 0.7 ?m, and a silver plated layer provided on the copper plated layer and having a thickness ranging from 0.1 ?m to 2 ?m. The push-button switch has a long operating life time, has a stable contact resistance, and is inexpensive.

Abstract: Parts of a base film that correspond to respective movable contacts are formed into projections. Operating projections each including a projecting member fixed to a top surface of the base film by an adhesive resin are formed and correspond to the movable contacts, respectively. The adhesive resins have different fixed diameters.

Abstract: In a metal dome sheet to be hermetically adhered to a plurality of metal domes disposed at electrodes on a substrate and to other portions of the substrate via an adhesive layer, the present invention provides an adhesive layer removed portion at a portion of the adhesive layer between at least two adjacent metal domes as an air escape portion. Accordingly, it is possible to obtain a thin and light switch panel, which is also excellent in water resistance and dust resistance.

Abstract: A keypad with both elevated and non-elevated key regions, and key switches disposed beneath both types of key regions. The non-elevated key regions each provide corresponding character output based on an operation algorithm that considers activation of at least one adjacent elevated key region as well as activation of the switch below the non-elevated key region. The keypad includes a keymat that is rigidly held at its perimeter in a stretched condition across a switch substrate. The key switches include metal snap domes that have an elevated central region forming a downwardly facing cavity defined at its edge by a ridge disposed above the switch contacts that electrically engages multiple switch contacts in an annular contact zone.

Abstract: A keypad of a mobile communication terminal includes a contact sheet having contacts preferably shaped as hemispherical domes which deflect to turn on/off switch contact point pairs on a printed circuit board. The contact sheet further includes band parts covering the domes and an insulating sheet having at least one pair of semicircular openings for exposing portions of the domes. The insulating sheet is preferably made of a light-reflecting material/color which disperses light to illuminate keys of the keypad.

Abstract: A movable contact unit including movable contacts localized in respective through holes of a base sheet formed from a flexible insulation substrate; a cover sheet formed from a flexible insulation substrate bonded on upper surface of the base sheet to hold respective movable contacts in the through holes; a weak adhesive layer applied on bottom surface of the base sheet of the movable contact unit except the through holes; and the movable contact unit bonded on stationary contact substrate having corresponding stationary contacts to respective movable contacts using the weak adhesive layer.

Abstract: A push switch includes a switch contact section including first and second contacts, and an elastic element for connecting the first and second contacts by pushing the first contact. The elastic element includes a columnar portion for connecting the first and second contacts by pushing the first contact, a hollow conical portion extending from a junction positioned at an end of the columnar portion, the conical portion having a truncated conical shape, and a thick portion provided at a whole circumstance of the junction.

Abstract: A first stationary contact is provided on the base body. A second stationary contact is provided on the base body. A conductive click spring is disposed over the first stationary contact and the second stationary contact, so as to be always electrically connected to the first stationary contact and so as to be away from the second stationary contact in a neutral position thereof. A push button includes a head portion which is depressed by an operator, and an actuator which pushes the click spring so as to be abutted against the second stationary contact when the head portion is depressed. The head portion and the actuator is integrally formed from rubber having elastic restorability.

Abstract: There is provided a contact spring in a small-sized push-button switch capable of lessening contact obstacle between contacts caused by fine dust, and reducing variation in load characteristics even if heat is applied thereto or the switch is repetitively operated.

Abstract: A key pattern connecting device for a domed metal switch. The domed metal switch includes first and second contact parts arranged in a key matrix on a main board. The key pattern connecting device comprises at least one first contact part electrically connected to columns by means of main connection patterns on the main board, at least one second contact part electrically connected to rows by means of the main connection patterns, a plurality of domed metal keys provided to the surfaces of the contact parts, respectively, and a flexible circuit attached to the main board in such a manner that the keys are projected through the flexible circuit. The flexible circuit has a plurality of connection patterns formed in such a manner that the connection patterns come into contact with the keys connected to the columns and the keys connected to the rows, respectively.

Abstract: The first movable contact including a ring portion and projections extended in same width as the ring is arranged against the peripheral fixed contacts and the central fixed contact at the bottom of the switch case in such manner that the ring portion confronts the peripheral fixed contacts at spaced intervals apart.

Abstract: A key pattern connecting device for a domed metal switch. The domed metal switch includes first and second contact parts arranged in a key matrix on a main board. The key pattern connecting device comprises at least one first contact part electrically connected to columns by means of main connection patterns on the main board, at least one second contact part electrically connected to rows by means of the main connection patterns, a plurality of domed metal keys provided to the surfaces of the contact parts, respectively, and a flexible circuit attached to the main board in such a manner that the keys are projected through the flexible circuit. The flexible circuit has a plurality of connection patterns formed in such a manner that the connection patterns come into contact with the keys connected to the columns and the keys connected to the rows, respectively.

Abstract: A sheet having contact plates includes a strip-shaped peel sheet that is peeled while being fed for use, a spacer sheet stuck onto the peel sheet via an adhesive layer, an upper face sheet stuck onto an upper face of the spacer sheet via an adhesive layer, and contact plates stuck to the upper face sheet. The peel sheet and the spacer sheet are provided with penetration holes through which the contact plates can penetrate, and coupling grooves by which the adjacent penetration holes are coupled in a direction crossing a feed direction of the peel sheet. The coupling grooves are shifted at one side in the widthwise direction thereof to rear ends in the feed direction of inner circumferences of the adjacent penetration holes so that there are no protrusions protruding in the feed direction from the rear ends of the inner circumferences of the adjacent penetration holes.

Abstract: A first conductive member and a second conductive member are disposed on a first face of a circuit board. A click spring is disposed on the first conductive member and deformed so as to establish an electrical contact between the first conductive member and the second conductive member, when a depressing force is applied thereto. An insulating film is disposed above the click spring. A spacer is interposed between the insulating film and the circuit board such that a first face thereof opposes to a first face of the insulating film and a second face thereof opposes to the first face of the circuit board. An adhesive layer is interposed between the first face of the circuit board and the second face of the spacer. The first adhesive layer has a viscosity such an extent that the spacer and the circuit board are detached from each other without damage.

Abstract: In a flexible switch, a circuit member having an electrode is provided on a adhesive sheet. A spacer sheet, having a through hole situated so as to correspond to the electrode on the circuit member, is provided on the circuit member. A front sheet, having a projected portion, is provided on the spacer sheet, in which a contact portion provided on an inner face of the projected portion is brought into contact with the electrode through the through hole in the circuit member when the projected portion is depressed. At least one of the adhesive sheet, the circuit member, the spacer sheet, and the front sheet has flexibility.

Abstract: An end of the present invention is to make it possible to input multi-valued signals by a manipulation to incline a key in a multi-direction-operative key switch, and disclosed is a structure of a multi-direction-operative key fitting to the end of the present invention.

Abstract: In a switch, an elastic member made of elastic material includes a bar section, a conical section at its upper portion functioning as a first deforming section, and a second deforming section at its lower portion. A movable contact in a switch case is pushed with the lower end portion of the second deforming section. A bar section of an elastic element projects through a central hole of a cover fixed to the switch case. In this switch, a pushing force applied to the elastic element deforms the first deforming section elastically, and then the second deforming section deforms elastically, and thus, the switch operates. The switch can absorb fluctuations due to combination of components of an electronic appliance, and stabilize its manipulation feeling through eliminating looseness of an operation button of the appliance.

Abstract: A key input device for portable terminals and the like, having a reduced sized and improved key input operation. The device has a wiring substrate, multiple keys on the substrate, with each key having three-dimensional displacement surfaces that are displacable in a linked fashion relative to one another. The displacement surfaces have a preceding displacement surface and a succeeding displacement surface corresponding respectively to a preceding and a succeeding key displacement. A first switching operation occurs when a first key part of a first key and first substrate part of the wiring substrate are brought into mechanical contact with each other on the basis of displacement of the preceding displacement surface. A second switching operation results when a second key part of a second key and a second substrate part of the wiring surface are contacted on the basis of displacement of the succeeding displacement surface.

Abstract: A dome switch includes a front sheet (22) which protrudes outside and can be reversed inside and has dome-shaped protuberances (27), each protuberance having an electrode provided therein; an FPC (24) serving as a circuit member having contact points (32), the electrodes of the protuberances being brought into contact when the protuberances (27) are reversed; and a spacer sheet (23) for preventing occurrence of deformation of the front sheet (22) which is to be interposed between the front sheet (22) and the FPC (24) and has through holes (29) formed therein for ensuring contact between the electrodes and the contact points (32). The spacer sheet (23) is caused to act also as a member for ensuring a stroke dimension of the protuberance (27).

Abstract: A simple-structured, highly dustproof movable contact unit having positive tactile response, and a panel switch using the same, and each manufacturing method. The movable contact unit contains movable contact (3), base film (11), and separator (4). The movable contact, which is made of a conductive metallic sheet having resiliency, is formed into a bottom-open dome-like shape. The base film holds the movable contact through adhesive layer (12) formed under the film. The base film has projections (13) corresponding to each movable contact, which are formed into a shape conforming to the dome-like movable contact. The upper surface of the separator, which has been subjected to a release treatment, is affixed with the adhesive layer beneath the base film. The root portion of the each projection conforming to the shape of the movable contact is tightly affixed to the separator through the adhesive layer under the base film.

Abstract: A spring coupled to a multi-layered flex membrane is described. In one embodiment, the spring may be a layer coupled to the top layer of a key switch membrane. In another embodiment, the spring may be coupled to the key switch between a top layer and a spacer layer. The spring or spring layer may increase the resiliency of the key switch membrane to prevent the flex membrane from deforming.

Abstract: A peripheral fixed contact having a circular hole is secured to a substrate, and a central fixed contact having a hole at a central portion thereof is secured to the substrate within the circular hole of the peripheral fixed contact. A spherical spring contact is mounted on the peripheral fixed contact so as to contact with an edge of the hole of the central fixed contact.

Abstract: The present invention relates to a laminate key sheet wherein a key sheet of a resin film having a display section is bent into a same form as the top and side faces of each resin button in order to be integrated with the resin button and where a cut-out is formed between the resin buttons. A rubber elastic sheet and the resin film are connected together through an adhesive interposing between an area between resin buttons of the key sheet and the rubber elastic sheet.

Abstract: A contact structure of a switch comprises a first contact (1), and one or more doughnut-like second contacts (2) surrounding the first contact (1), and the second contacts (2) are provided with one or more band-like contacts (3a), (3b), (3c), (3d) extending to the opposite side from the first contact (1). With this structure, an area of a metal pattern portion of the second contact (2) becomes smaller as compared with prior art. In a compact electronic device used for a numeric keypad of a mobile telephone or the like, the contact structure can be reduced in size and weight to the utmost and resources can be saved to the utmost.

Abstract: In a switch, an elastic member made of elastic material includes a bar section, a conical section at its upper portion functioning as a first deforming section, and a second deforming section at its lower portion. A movable contact in a switch case is pushed with the lower end portion of the second deforming section. A bar section of an elastic element projects through a central hole of a cover fixed to the switch case. In this switch, a pushing force applied to the elastic element deforms the first deforming section elastically, and then the second deforming section deforms elastically, and thus, the switch operates. The switch can absorb fluctuations due to combination of components of an electronic appliance, and stabilize its manipulation feeling through eliminating looseness of an operation button of the appliance.

Abstract: A movable contact structure which, even when used in a planar circuit board, can provide a crispy click feeling and will not fail to return to an original position after being inverted is to be provided. The structure consists of a disc formed into a dome shape by cupping a center of a thin metallic sheet in one direction, provided with a skirt rising at a prescribed angle from an outer circumference of this disc toward a center of the disc, and a dome which is continuous from this skirt and can be repetitively inverted, the connecting part between the skirt and the dome being formed in multiple steps via a plurality of bent portions.

Abstract: A first conductive member and a second conductive member are disposed on a first face of a circuit board. A click spring is disposed on the first conductive member and deformed so as to establish an electrical contact between the first conductive member and the second conductive member, when a depressing force is applied thereto. An insulating film is disposed above the click spring. A spacer is interposed between the insulating film and the circuit board such that a first face thereof opposes to a first face of the insulating film and a second face thereof opposes to the first face of the circuit board. An adhesive layer is interposed between the first face of the circuit board and the second face of the spacer. The first adhesive layer has a viscosity such an extent that the spacer and the circuit board are detached from each other without damage.

Abstract: An electrical switch includes a snap dome tripper (36) whose center portion (37) snaps down when depressed by a predetermined amount, and a contact plate (44) with blades (50) that move down against terminals (26) to close the switch when the tripper snaps down, and to provide tactile feedback when the switch is closed. Instead of the center portion of the contact plate lying under the center portion of the tripper, the contact plate lies above the tripper and the contact blades project horizontally beyond the boundaries of the periphery of the tripper.

Abstract: A thin and inexpensive sheet with plate springs is provided which can prevent the entry of dust and other foreign matters and which is strong against static elasticity. One side of an adhesive sheet is studded with adhesive portions in a projected state, and vent portions are formed between the studded adhesive portions and between movable contacts and the exterior of the adhesive sheet to permit the entry and discharge of air. Consequently, the whole upper and lower surfaces of the movable contacts can be covered with the adhesive sheet and a separator to prevent the entry of dust and other foreign matters.

Abstract: The present invention provides a sheet having moving contacts and a sheet switch that are constructed so as to contribute to lowering of costs by reducing the number of parts, provide satisfactory operation feeling when the moving contacts are pressed, and provide high contact reliability by preventing invasion of dust. The sheet having moving contacts comprises: a sheet having an adhesion face, made of an insulating film, which is coated with an adhesive on a lower face thereof; and a moving contact which has a domed expansion part and the upper face of which is covered with and stuck to the adhesion face of the sheet, wherein the sheet is formed with a linear slit extending toward the top of the expansion part across an outer circumferential edge of the moving contact.

Abstract: A surgical handpiece (20) for performing medical procedures. The handpiece (20) has a housing (24) and a membrane switch assembly (22) is mounted to the housing for regulating the operation of the handpiece. The membrane switch assembly has a switch plate (64) mounted in a cavity (42) formed in the housing. The switch plate includes a pair of spaced apart contact pads (86, 87). A dome (120) formed of flexible metal is spaced over the contact pads. A keypad (138) extends over the top of the switch cavity to cover the switch plate. A bezel plate (46) is fitted over the keypad. The keypad is compressed between the bezel plate and the housing to form a seal around the switch cavity. Depression of the keypad results in the dome flexing inwardly and closing the connection between the contact pads.

Abstract: An electrical switch laminate includes: a flexible membrane layer, a plurality of sub layers including a backing layer, electrical contacts of the switch within a switch cavity of the laminate, and an electrically conductive upper contact within the switch cavity of the laminate. The flexible membrane layer overlays and partially encloses the switch cavity that is airtight except for a vent passage extending along a major surface of one of the sub layers to equalize the pressure between the switch cavity and a surrounding environment.

Abstract: A simple-structured, highly dustproof movable contact unit having positive tactile response, and a panel switch using the same, and each manufacturing method. The movable contact unit contains movable contact (3), base film (11), and separator (4). The movable contact, which is made of a conductive metallic sheet having resiliency, is formed into a bottom-open dome-like shape. The base film holds the movable contact through adhesive layer (12) formed under the film. The base film has projections (13) corresponding to each movable contact, which are formed into a shape conforming to the dome-like movable contact. The upper surface of the separator, which has been subjected to a release treatment, is affixed with the adhesive layer beneath the base film. The root portion of the each projection conforming to the shape of the movable contact is tightly affixed to the separator through the adhesive layer under the base film.

Abstract: A dome switch (12) of an electrically operated product (10) includes an electrically conductive dome switch member (30) having a central dimple (36) and a peripheral portion (38) that is secured by two retainers (42) which permit sliding alignment of the dome switch member. A switch actuator (44) of the dome switch (12) has an alignment button (46) received by the dimple (36) of the dome switch member (30) so as to provide sliding of the dome switch member on a circuit board (16) and thereby providing alignment with first and second contacts (18, 20) to provide effective switch closing.

Abstract: A dome switch includes a front sheet (22) which protrudes outside and can be reversed inside and has dome-shaped protuberances (27), each protuberance having an electrode provided therein; an FPC (24) serving as a circuit member having contact points (32), the electrodes of the protuberances being brought into contact when the protuberances (27) are reversed; and a spacer sheet (23) for preventing occurrence of deformation of the front sheet (22) which is to be interposed between the front sheet (22) and the FPC (24) and has through holes (29) formed therein for ensuring contact between the electrodes and the contact points (32). The spacer sheet (23) is caused to act also as a member for ensuring a stroke dimension of the protuberance (27).