Abstract: A capacitive sensing assembly comprises a nonconductive interface material, a conductive plastic, an electrode, and a controller. The capacitive sensing assembly is configured to detect a proximity of skin to the nonconductive interface material. The nonconductive interface material comprises a first surface and a second surface that are opposite one another. The first surface receives contact with the skin. The conductive plastic is coupled to the second surface of the interface material. The electrode is electrically coupled to the conductive plastic and configured to provide an electrical signal. The electrical signal corresponds to a surface capacitance of the nonconductive interface material that is based in part on the conductive plastic, the nonconductive interface material, and the proximity of the skin to the interface material. The controller determines the proximity of the skin based on the electrical signal that corresponds to the surface capacitance.

Abstract: According to various embodiments, there is provided a key switch mechanism including: a key button; a plunger attached to the key button and displaceable between a neutral position and an activation position; an elastomeric dome which, when the plunger is in the neutral position, is non-deformed and which, when the plunger is in the activation position, is elastically deformed by the plunger; a conductive spring having a stationary end portion and a moveable end portion, the stationary end portion electrically coupled to a circuit, and the moveable end portion coupled to the elastomeric dome in a manner to be moved when the plunger is displaced towards the activation position, in connection with the corresponding deformation of the elastomeric dome; and an electrical contact electrically coupled to the circuit, wherein, when the plunger is in the neutral position, the electrical contact is arranged at a distance from the moveable end portion, and, when the plunger is in the activation position, the moveable e

Abstract: In accordance with at least one embodiment, a touch sensor is disclosed. The touch sensor includes a first electroconductive pattern including at least two electrodes. The touch sensor further includes a second electroconductive pattern configured to mask a portion of the first electroconductive pattern when positioned over or under the first electroconductive pattern. The second electroconductive pattern masks the portion of the first electroconductive pattern such that an unmasked portion of the first electroconductive pattern includes unmasked portions of the at least two electrodes. The unmasked portions are of approximately equal length.

Abstract: An electronic apparatus capable of preventing keytops or a pointing stick from protruding from a chassis top surface when not being in use is disclosed. The electronic apparatus includes a set of keytops each movable up and down between a first position to which the keytop ascends by a biasing force of a rubber dome and a second position to which the keytop descends against the biasing force; a set of drive members each extend along the left-right direction, each movable in the left-right direction relative to the keytops; a link member connecting adjacent drive members to enable coordinated operation; and a drive mechanism that moves one of the drive members connected by the link member.

Abstract: A keyswitch with adjustable tactile feedback is adjusted by an adjusting method. The keyswitch includes a baseplate, an upper housing, an upper bushing component, a lower bushing component, a keycap and a recovering component. The baseplate has an electrode module, the upper housing is disposed on the baseplate, the upper bushing component is movably disposed on the upper housing, the lower bushing component is movably located between the baseplate and the upper housing, and the keycap is connected to a connecting portion of the upper bushing component. The lower bushing component can rotate relative to the baseplate to switch between a first position and a second position. The lower bushing component has a first lateral surface and a second lateral surface with different shapes. The recovering component is disposed between the baseplate and the lower bushing component to upwardly push the lower bushing component.

Abstract: A touch sensitive mechanical keyboard configured to enable a standard look and feel mechanical keyboard to sense fine hand/finger motion over the surface of the keys. Command and cursor input (e.g., pointing and gestures) can be received from the user on the touch sensitive mechanical keyboard without requiring the user to move the user's hand off the keyboard. Fine hand/finger motion detection can be enabled by embedding clusters of capacitive sensors near the surface of the keyboard's keys. The touch sensitive mechanical keyboard can operate in two or more modes—e.g., a typing mode and a mouse mode—and operating the keyboard in mouse mode or switching between the modes can be facilitated by holding (depressing and holding) or tapping (depressing and releasing) arbitrary combinations of keys, or by detecting the number of fingers touching the touch sensitive mechanical keyboard.

Abstract: A touch sensor assembly may include a sensor mounting portion formed at a insulating substrate, and a soldering spot provided at the sensor mounting portion, wherein a touch sensor is stably fixed to the sensor mounting portion by the soldering spot. In addition, the touch sensor assembly according to an embodiment of the present disclosure includes a copper coating film coated on a insulating substrate, and a top layer printed on the copper coating film, wherein the copper coating film is protected by the top layer.

Abstract: A keyboard has a keyswitch capable of showing its movement depth. The keyswitch includes a substrate, a lifting unit, a multistage positioning component and a keycap. The lifting unit is disposed on the substrate. The multistage positioning component is disposed on the substrate and has a plurality of first actuating portions. The keycap is connected with the lifting unit and adjacent by the multistage positioning component. The keycap has a second actuating portion. The keycap is moved relative to the substrate via the lifting unit, and the second actuating portion can contact against one of the plurality of first actuating portions to generate a feedback signal.

Abstract: Particular embodiments described herein provide for a keyboard that includes a plurality of keys; and a plurality of key actuators. At least a portion of the key actuators raises at least a portion of the plurality of keys when the portion of the plurality of key actuators is activated. In more particular embodiments, the dome supports comprise a dielectric that deforms in a ‘z’ direction with respect to the keyboard when activated to raise the portion of the plurality of keys.

Abstract: A novel semiconductor variable capacitor is presented. The semiconductor structure is simple and is based on a semiconductor variable MOS capacitor structure suitable for integrated circuits, which has at least three terminals, one of which is used to modulate the equivalent capacitor area of the MOS structure by increasing or decreasing its DC voltage with respect to another terminal of the device, in order to change the capacitance over a wide ranges of values. Furthermore, the present invention decouples the AC signal and the DC control voltage minimizing the distortion and increasing the performance of the device, such as its control characteristic. The present invention is simple and only slightly dependent on the variations due to the fabrication process. It exhibits a high value of capacitance density and, if opportunely implemented, shows a quasi linear dependence of the capacitance value with respect to the voltage of its control terminal.

Abstract: An ITO sensor design and method for making the same is optimized to minimize noise from an LCD. The design includes a two layer sensor design having a transmitter line (Tx) placed in a first layer and a receiver line (Rx) placed in a second layer in a diamond-shaped pattern. The diamond shape maximizes the sensitivity of the sensor.

Abstract: A thin keyboard having multiple keys is disclosed. At least one of the keys includes a key magnet, and a holding magnet is mounted on a transverse slider. The key is located in a ready position by a magnetic attraction of the holding magnet to the key magnet. When the transverse slider is slid, a separating protrusion pushes a chamfer to widen the distance between the holding magnet and the key magnet. The distance between both magnets is also widened in a right and left direction, and when the magnetic attraction drops, the key is located by gravity in a release position.

Abstract: An electronic device may be provided with a housing having housing sidewalls. A plate may be connected between a pair of the sidewalls. An audio jack may be mounted to the plate. A microphone may be mounted within the device between the audio jack and a given one of the sidewalls. A vibrator may be mounted between one of the sidewalls and the audio jack using a bracket. The vibrator may have a weight that is tapered along its length. A button may be formed in an opening in one of the housing sidewalls. The button may have a button member with a protrusion that extends through a button opening in the sidewall. A support structure may be interposed between a switch and the button member. The switch may have a portion that extends through an opening in the support structure and that is actuated by the button member.

Abstract: An electronic device may have buttons, a display, and a vibrator unit. Buttons may be included in electronic devices such as glass buttons, metal buttons, buttons that are assembled on printed circuit boards, and buttons that are partly formed from antenna structures. Button coatings may be used to improve the sliding performance of metal-on-metal buttons. A layer of polymer may be interposed between a button plate and a housing structure. A glass button member may have an underside on which a layer of patterned ink is formed. Elastomeric members may be used to reduce button rattle. Portions of a button may be provided with conductive features that form portions of an antenna.

Abstract: A key button mechanism and a portable electronic device using same are provided. The key button mechanism includes a base body, a protective piece and a key button. The protective piece is assembled to the base body and includes two actuating portions. The key button is partially attached to the base body and aligns with the protective piece. The key button includes a key body and two resisting blocks formed on the key body. The two resisting blocks are configured to align with and abut against the corresponding two actuating portions of the protective piece.

Abstract: A variable capacitor includes: a dielectric sheet disposed on a substrate and covering an electrode pattern on the substrate; a resilient conductive supporting seat mounted on the dielectric sheet for supporting an insulating operating cap on a central portion thereof; a conductive cover body covering the conductive supporting seat and permitting the operating cap to extend outward; and a biasing member for biasing the central portion of the conductive supporting seat to move away from the substrate. The cover body is connected electrically to the conductive supporting seat and a conductive contact on the substrate. When the operating cap is depressed, the operating cap forces a contact portion of the conductive supporting seat to deform such that a surface area of the deformed contact portion that contacts the dielectric sheet is increased, thereby changing the capacitance between the conductive supporting seat and the electrode pattern.

Abstract: A variable capacitor includes: a dielectric sheet disposed on a substrate and covering an electrode pattern on the substrate; a resilient conductive supporting seat mounted on the dielectric sheet for supporting an insulating operating cap on a central portion thereof; a conductive cover body covering the conductive supporting seat and permitting the operating cap to extend outward; and a biasing member for biasing the central portion of the conductive supporting seat to move away from the substrate. The cover body is connected electrically to the conductive supporting seat and a conductive contact on the substrate. When the operating cap is depressed, the operating cap forces a contact portion of the conductive supporting seat to deform such that a surface area of the deformed contact portion that contacts the dielectric sheet is increased, thereby changing the capacitance between the conductive supporting seat and the electrode pattern.

Abstract: A capacitive type touch panel includes: a transparent substrate; an array of first conductors formed on a surface of the transparent substrate; an array of second conductors formed on the surface of the transparent substrate; a plurality of conductive first bridging lines, each of which interconnects two adjacent ones of the first conductors; a plurality of conductive second bridging lines, each of which interconnects two adjacent ones of the second conductors and each of which intersects insulatively a respective one of the first bridging lines; and a plurality of spaced apart insulators, each of which is disposed at an intersection of a respective one of the first bridging lines and a respective one of the second bridging lines to separate the respective first and second bridging lines.

Abstract: An electrical touch sensor is provided. The electrical touch sensor includes: a touch detection part having at least one touch pad and generating a first signal having a same delay time regardless of whether the object is in contact with the touch pad and a second signal having a varied delay time according to whether the object is in contact with the touch pad; and a contact signal generator generating a contact signal in response to the delay time-difference between the first and second signals. Therefore, it is possible to increase operation reliability by precisely determining whether the object is in contact with the pad, when the object has charge accumulation characteristics more than a certain level, although its conductive is insufficient. In addition, the electrical touch sensor can determine whether the object is in contact with the pad using only one pad to reduce a layout area of a product.

Abstract: A key module includes a key body and an elastic element. The key body has a key surface. The elastic element, which has a side surface, is disposed around the circumference of the key body. The key surface of the key body and the side surface of the elastic element constitute a pressing surface.

Abstract: An electronic device has an operating panel. A through-hole penetrating the operating panel is provided at a part of the operating panel. A partition board includes a board part and a partition part, and a step is provided between the board part and the partition part. In an area where the through-hole and the board part of the partition board are to be formed, a metal mold can be thickened. In an area where a narrow gap on a surface side of the operating panel is to be formed, the length of the metal mold can be reduced. Therefore, the strength of the metal mold can be maintained. Also, the step of the partition board, which separates the board part and the partition part, prevents visual recognition of the through-hole by a user.

Abstract: A capacitive light/dimmer switch which uses soft or fuzzy fabrics made with electronic textiles instead of, or as an extension of, metal or plastic plates. The soft fabric material, which may be in the form of a pompom, tassel, fur, or other electronic trim element, provides an attractive and compelling user interface that is soft to the touch. The user simply touches the pompom, as he would the dimmer plate, to cause the amount of light to increase or decrease. The electronic textiles of the light controller comprise electrodes integrated into their yarns or fibers, resulting in a conductive material (electronic textile) that may be used as the user interface. This conductive material is electrically connected to a sensing circuit by either AC coupling or DC contact. When the user touches the conductive material, the sensing circuit measures the change in load of the electrodes, and the lighting is changed.

Abstract: A touch switching apparatus includes: a switching unit for evenly illuminating on a touch unit manipulated by a user among touch units with marks; and a driving circuit for driving the switching unit when detecting the manipulation. The touch switching apparatus includes: an insulating unit for inducing a capacitance as a user's body contacts and presented with a touch switch for manipulation of an instrument; a conductive unit for detecting a capacitance through the medium (dielectric) of a user's body contacting the insulating unit; a flat light emitting device for providing a backlight to the insulating unit to visibly express a corresponding switching unit when a body contact is detected by the conductive unit; and a drive unit for detecting whether a switch has been manipulated according to a change in a capacitance made by the conductive unit.

Abstract: A method for filtering an electrical signal. The invention includes the steps of rotating a conductive disc (105) about an axis (135), applying a magnetic field (205) to the conductive disc (105) in a direction that is generally parallel to the axis of rotation (135), electrically connecting a first and second conductor (215, 220) to the disc (105) at radially spaced locations thereon, and connecting the first and second conductors (215, 220) in at least one of a series and parallel configuration. The conductive disc (105) can be formed in a recess (130) in a substrate (125) which can have a printed circuit or an integrated circuit. The substrate (125) can consist of a semiconductor or ceramic, such as a low temperature co-fired ceramic. The first and second conductors (215, 220) and the conductive disc (105) rotating in the magnetic field (205) can define an electro-mechanical capacitor (100), which can be used for capacitively filtering a signal. An inductor also can be provided.

Abstract: An input device for a personal computer or the like has an elastic member, a slider horizontally movable on the elastic member, and a key top operatively connected to the elastic member through the slider. The elastic member 5 has a coupling portion provided with a flange which vertically movably fits in a fit hole formed in the slider. A horizontal movement of the key top causes the wall of the fit hole of the slider to press the flange, which in turn causes deformation of the flange and of the movable electrode, with the result that the size of the gap and, hence, capacitive value between the movable electrode and the fixed electrode are changed, whereby the direction of movement of the key top is detected with a high degree of accuracy.

Abstract: An input device for a personal computer or the like has an elastic member, a slider horizontally movable on the elastic member, and a key top operatively connected to the elastic member through the slider. The elastic member 5 has a coupling portion provided with a flange which vertically movably fits in a fit hole formed in the slider. A horizontal movement of the key top causes the wall of the fit hole of the slider to press the flange, which in turn causes deformation of the flange and of the movable electrode, with the result that the size of the gap and, hence, capacitive value between the movable electrode and the fixed electrode are changed, whereby the direction of movement of the key top is detected with a high degree of accuracy.

Abstract: A contact device consisting of a helical spring which is adapted from SMD mounting, and which is formed with a base portion adapted to be positioned on and attached to a contact face by soldering or gluing, and with a top portion adapted for handling with a tool preferably associated with an SMD apparatus. This provides the possibility of achieving a generally better and less expensive contacting between components, such as acoustic transducers, batteries or the like and printed circuit boards by means of simple features. Constructing the contact device as a screw or helical spring provides a great safeguard against transfer of laterally directed forces or moments from the contact face which destroy the contact face and/or the solder connection with the printed circuit.

Abstract: A variable capacitor in a semiconductor device is described in which the capacitance is varied by the movement of a dielectric material in the space between the plates of the capacitor in response to an external stimulus. A method of making such a variable capacitor is also described in which the capacitor is built in a layered structure with the top layer including a portion of dielectric material extending into the space between the capacitor plates. After formation of the top layer, an intermediate layer is etched away to render the top layer flexible to facilitate movement of the dielectric material in the space between the capacitor plates.

Abstract: A capacitive switch assembly includes an elastomeric sheet actuator for elastically supporting a switching member above a capacitive element comprised of a pair of conductive plates and a dielectric sheet. The elastomeric sheet supports the switching member so that upon user actuation to compress the elastomeric sheet, the switching member is directed to engage the capacitive element and selectively compress to effectively form a variable capacitor. Resilient deformation of the switching member can further vary the capacitance of the capacitor in an electrically detectable manner.

Abstract: A multiple position or continuously variable capacitive switch which operates by producing a series of discernable changes in the capacitance between a pair of conductors (14,16) disposed in a spaced coplanar relationship on a surface of a non-conductive substrate (12). A dielectric layer (18) is applied over the conductors (14,16) and exposed areas of the substrate (12) surface. A resilient conductive pad (20) is positioned atop the dielectric layer (18) and a user movable actuator (28) is moved to controllably increase the capacitance between the conductors (14,16) by creating progressively greater areas of compression between conductive pad (20) and dielectric layer (18).

Abstract: A capacitance change switch with a resiliently deformable conductive pad compressible against a dielectric coating on the surface of a pair of spaced coplanar thin foil plates formed on a refractory substrate. The pad forms with the plates a pair of capacitors electrically in series. User movement of an actuator causes pad compression and a significant electrically detectible change in capacitance for effecting a switching function. In one embodiment the pad is formed of conductive elastomer and in another embodiment the pad is formed of non-conductive elastomer with a conductive foil covering.

Abstract: Information representing the state of switches carried on a pointing device handle is carried to an associated computer via a capacitive coupling technique.

Abstract: A capacitive switch assembly formed on a glass substrate with one capacitive plate formed of a thin metal film deposited thereon covered by a dielectric spacer deposited thereover for spacing therefrom a second plate formed of conductive polymer paste screened on the dielectric spacer. Discontinuities are provided in the second plate which is brought in-circuit by a conductive elastomer shorting bar movable upon user actuation of the switch.

Abstract: In a capacitive-type switch having two capacitive levels, a relatively thin blade of a desired dielectric material is interposed between two capacitive plates by downward actuation of a push-button switch so that the plates become separated by the blade. When the push button is released, the blade is removed from between the two capacitive plates and a high capacitance level is once again achieved.

Abstract: Disclosed is a capacitance keyboard switching device comprising a fixed electrode formed on one surface of a first insulating film, a movable electrode formed on one surface of a second insulating film, a spacer interposed between the first and second insulating films and provided with a switching opening formed through the spacer for allowing the fixed and movable electrodes to come close to and separate from each other with one of the first and second insulating films interposed between the fixed and movable electrodes, a movable electrode depressing member provided with a depressing portion for depressing the movable electrode to cause the movable electrode to come close to the fixed electrode through the one insulating film, in order to keep the movable electrode flat when the movable electrode is depressed toward the fixed electrode, the depressing portion is provided with a surface area selected to be larger than a surface area of the movable electrode so that the surface area of the depressing member c

Abstract: There is described a device, comprised of a frame or substructure, four arms arranged in cross shape or substantially in cross shape and hingedly supported on knife-edge in said frame, a weighing plate vertically movable relative to said frame, bearing through knife-edges on said arms, in notches provided therefor in the arms, in which said arms bear with the mutually-facing ends thereof on a box-design sensor, whereby the sensor capacity is changed proportionally to that force being exerted on said weighing plate, and in which said sensor is formed by a box-like holder with a bottom whereon a first insulated armature which acts as lowermost capacitive plate, is firmly secured.

Abstract: A key switch including a substrate prepared from dielectric material, and first and second electrodes respectively formed on the bottom and top surfaces of the substrate to constitute a capacitor together with the substrate. The first electrode is electrically connected to a pulse voltage signal oscillator, thereby pulsatively storing a static capacitance between the first and second electrodes. A first fixed contact electrically connected to the second electrode is provided on that portion of the surface of the substrate. A second fixed contact is positioned near the first fixed contact. The first and second fixed contacts are electrically connected or shut by a manually operable movable conductive rubber contact.

Abstract: A keyboard switch is provided with an insulating substrate, a first electrode laid on the insulating substrate, a second electrode formed of a conical coil spring and facing the first electrode, a dielectric disposed on the first electrode, a button positioned on the top portion of the second electrode, and a rubber cap disposed between the button and second electrode, for giving snap feeling to an operator when the button is depressed and the capacitance of the switch exceeds a given value. The capacitance varies with the change in the facing area which changes substantially in proportion to the depth of depression of the button. The switch is capacitive-coupled for a switching operation and the snap feeling is given to the operator when the capacitance exceeds the given value.

Abstract: A capacitance membrane switch (1) including first (64,68), second (52,58) and third capacitor plates (44-48) wherein the third capacitor plates consist of conductive adhesive.

Abstract: A capacitive or a membrane switch is provided with a coil spring which has a conical base and a top cylindrical portion. The spring biases a switch key to its rest position. When the key is pressed, the conical base is compressed to provide an exponentially increasing counter-force and to actuate the switch at a predetermined actuation point. After the switch is actuated, the key continues to move and compresses the cylindrical portion of the spring to provide a linearly increasing counter-force which indicates overtravel operation of the switch.

Abstract: A keyboard assembly having key-switches, comprising a key holder plate supporting multiple keys in plural rows and movably across the thickness of the plate, and further comprising an upper casing which has a rectangular aperture closed by the key holder plate. The key holder plate has holes through which the keys extend, and integral guide portions concentric with the holes and extend toward the rectangular aperture. Opposite right and left sides of the aperture perpendicular to the rows of the keys are defined by side walls of the upper casing each of which has a downward extension toward the key holder plate. The extension has a convex lower end profile with which the key holder plate is held in pressed contact by fasteners, with elastic deformation thereof following the convex lower end profile of the downward extension, such that a surface generally defined by top faces of the keys is curved in cross section across the rows of the keys.

Abstract: A keyboard switch assembly is disclosed which utilizes a new switch design for providing tactile feedback to the user while nevertheless permitting long switch life. The keyboard switch assembly provides adjustable touch control to the user via a mechanical adjustment means while requiring minimal key travel. The "sandwich" arrangement of the dome and the membrane switch isolates the contacts from contamination upon activation resulting in long switch life. Furthermore, integration of all the parts in the assembly of this keyboard switch makes this keyboard more competitive and cost effective.

Abstract: A keyboard switch comprises an insulating substrate, a first electrode laid on the insulating substrate, a second electrode formed of a conical coil spring and facing the first electrode, a dielectric disposed between the first and second electrodes, and a bottom for linearly changing the facing area between the first and second electrodes. The capacitance between the first and second electrodes is changed linearly so that the first and second electrodes are capacitive-coupled for switching operation when the capacitance exceeds a given value.

Abstract: A capacitance keyboard switch is provided which reduces in a keyboard the overall space requirements therefore while providing at the same time the property of increasing the switch module force curve in the activating movement thereof. The tactile feel construction includes a reduced number of integrally molded inexpensive parts.

Abstract: A capacitive switching device having a pair of stationary electrodes, a movable electrode disposed capacitively relative to the stationary electrodes, and an actuator carrying the movable electrode and including a resilient member biasing the actuator away from the stationary electrodes. The movable electrode comprises a sponge member having non-porous layers on opposite sides thereof, and a resilient conductive layer adhering to one of the non-porous layers. The other non-porous layer is secured to the actuator such that the resilient conductive layer faces the stationary electrodes. A process of manufacturing the device is also disclosed.

Abstract: A capacitive switch employs a conical conducting spring disposed within a switch housing in spaced relation to an underlying capacitive plate which is covered by a dielectric layer. The bottom coil of the spring engages slots of the housing so that the spring is held above the capacitive plate. A substantially zero capacitance is defined when the switch is in its rest state with the spring biasing a switch pushbutton upwardly. When the pushbutton is pressed, the spring is compressed against the underlying capacitive plate. The compressed coils of the spring define a predefined capacitance which indicates the depressed condition of the switch.

Abstract: An improved capacitive keyboard includes a plurality of switch keys that each define a minimum capacitance when in a fully extended rest state and a maximum capacitance when pressed. Each switch key has a plunger mechanism that compresses a capacitive spring when the key is pressed and releases the spring when the key is released. Each capacitive spring is affixed in operational orientation over an associated capacitive pad by soldering areas of the base coil of the spring to adjacent plated holes in a supporting printed circuit board. In operation, molten solder is applied at the underside of the printed circuit board and passes up through the plated holes by capillary action to contact the base coil of the spring. The hardened solder holds the spring in its operational position on the printed circuit board and conductively contacts the spring with an output terminal of the board.

Abstract: A low profile keyswitch utilizes a telescoping plunger assembly. A linear feel and overtravel are achieved. The telescoping plunger assembly includes an outer plunger shaft and an inner plunger shaft slideably mounted therewithin for telescopic extension therefrom. A retaining member locks one end of the inner plunger shaft within the outer plunger shaft, thereby defining the maximum extension of the inner plunger. A spring biases the inner plunger into its fully extended position.

Abstract: A capactive keyswitch utilizes an arrangement of three spring forces to provide a linear feel, hysteresis, and overtravel. A telescoping plunger assembly includes an outer plunger shaft and an inner plunger shaft slideably mounted therewithin for telescopic extension therefrom. A first spring provides a return force to maintain the keyswitch in its non-actuated condition. A switch actuator is coupled to the inner plunger shaft and includes a resilient foam pad (second spring) to provide resilient contact with a switching element when the plunger is moved to an actuated position. A third spring between the outer plunger shaft and the switch actuator urges the switch actuator, and thereby the inner plunger shaft, into its fully extended position.

Abstract: A keyboard assembly having key-switches, comprising a key holder plate supporting multiple keys in plural rows and movably across the thickness of the plate, and further comprising an upper casing which has a rectangular aperture closed by the key holder plate. The key holder plate has holes through which the keys extend, and integral guide portions concentric with the holes and .[.extend.]. .Iadd.extending .Iaddend.toward the rectangular aperture. Opposite right and left sides of the aperture perpendicular to the rows of the keys are defined by side walls of the upper casing each of which has a downward extension toward the key holder plate. The extension has a convex lower end profile with which the key holder plate is held in pressed contact by fasteners, with elastic deformation thereof following the convex lower end profile of the downward extension, such that a surface generally defined by top faces of the keys is curved in cross section across the rows of the keys.