Switch control element and switch

Abstract

Control element (101) for electrical switching, comprising: a control surface (103) that can be moved by applying force with a finger (105), wherein the control surface (103) can be moved from an initial position (P0) by applying an initial force (F0), wherein the switching is carried out by applying a second force (F2) that is smaller than the initial force (F0), wherein when moving the control surface (103) between a first path length (s1), where a first force (F1) is required, and the second path length (s2) there is a greater change in force per path length than when moving the control surface (103) between the initial position (P0) and the first path length (s1), wherein the force required for moving between the initial position (P0) and the first path length (s1) is constant, increases or decreases.

Description

The present application relates to an operating element, in particular for a vehicle, for electrical switching and to a switch which has the operating element.DE 10 2006 042 645 B4 discloses a multifunctional display and operating device in a motor vehicle, wherein operating elements are designed as keys, which can each be pivoted about an axis of rotation running parallel to a surface of the display panel in or at an end region of the keys, wherein the keys each have a key cap with operating surfaces, wherein the keys have a plunger protruding from a side opposite the operating surfaces of the operating elements, one end of which plunger interacts with a switching element of a switching mat when the operating element is operated. Also shown is a graph which shows a force as a function of a deflection of the operating element which is exerted by the switching element via the plunger upon actuation of the operating element thereon perpendicularly to the printed circuit board. If the operating element is actuated, the force that the switching element transmits to the operating element via the plunger initially rises steadily and reaches a local maximum in the case of a specific deflection. With an increasing deflection, the exerted force decreases again until it reaches a local minimum at a stop point, wherein the force increases very steeply again beyond a deflection beyond the stop point.DE 10 2005 054 677 A1 discloses a touch-sensitive operating unit with haptic feedback, wherein the operating unit has a touch-sensitive input element and means for generating a haptic feedback, wherein a compression spring element with a non-linear spring characteristic curve is used for generating the haptic feedback, wherein the input element is movable counter to a spring force of the compression spring element. The spring characteristic curve goes through a maximum during the movement of the input element, so that the user is provided with the feel that the operating unit has a pressure point. As the pressure of the switching domes increases, the force generated by the switching domes first increases, after passing through a maximum it decreases, passes through a minimum and subsequently increases again.DE 10 2008 004 909 A1 discloses an operating element with improved tilting haptics, wherein the operating element has an operating knob, a bearing point for the operating knob located in a housing of the operating element, an extension firmly connected to the operating knob, a first permanent magnet fastened to the extension and a second permanent magnet fastened in the housing, wherein the permanent magnets form a permanent magnet pair and wherein in a central position of the operating knob unequal poles of the magnets are situated opposite one another at a distance. The counterforce that a user must overcome to tilt a primary lever arm decreases again after overcoming a force maximum and increases again after reaching an end stop. A decrease in the restoring force gives the user haptic feedback that the shifting operation has occurred, the decrease in the force being referred to as a snap.U.S. Pat. No. 6,847,000 B1 discloses a device and a method for a snap switch with a negative characteristic curve. The apparatus generally includes a plunger connected to an actuation lever, a stationary armature, a movable contact, and at least two stationary contacts. The apparatus also includes a snap spring assembly responsive to the actuation lever, wherein a central spring member is axially pressurized and flexed into a resilient buckling shape to form a switch wherein the movable and stationary contacts are responsive to an actuation force derived from the snap spring assembly.Conventional controls have haptics that have several problems. The haptics do not have a sufficiently meaningful and precise effect in some cases, and the mechanical constraints, such as requirements for the installation of the control relative to a housing, relative to a guide, or relative to elements of the switch, can give rise to inaccurately perceived switching or other problems of switching.It is therefore an object of the present invention to propose an operating element and a switch with the operating element, wherein precise electrical switching can be achieved by actuating the operating element and switching malfunctions are reduced. It is a further object of the present invention to propose an operating element and a switch with the operating element, wherein a switching takes place at a defined actuation characteristic and can thus be carried out reliably. It is furthermore an object of the present invention that a defined feedback perceptible to the user is generated during the switching operation. In particular, the mechanical boundary conditions for optimizing the design should be improved.The object is achieved by an operating element having the features of claim 1. According to the invention, the operating element for electrical switching has an operating surface which can be displaced by exerting force by means of a finger. The control panel is displaceable starting from an initial position under application of an initial force, wherein the shifting is effected under application of a second force which is smaller than the initial force. It is essential here that, in the case of a displacement of the operating surface between a first distance, in which a first force is required, and the second distance, a greater change in the force per distance takes place than in the case of a displacement of the operating surface between the initial position and the first distance.The operating element can be usable for actuating any electrical switch, for example for actuating a button, a button, a rocker switch, a rocker switch, a pressure switch, a latching switch, a slide switch, a pushbutton switch, a foot switch or the like. The control element can comprise various materials, such as plastic, rubber, silicone, metal, glass, etc. The switching can be triggered by the control surface of the control element being displaced by a specific displacement path (a second displacement path) starting from the initial position by applying force along a displacement direction (for example at least approximately perpendicular to the control surface). The initial position of the operating surface may represent a position of the outer surface of the operating element that is accessible by a user when no force is applied to the operating surface from the outside. The initial position can correspond in particular to a zero position in a graph illustrating the displacement of the operating surface by a specific distance along the displacement direction. In order to displace the operating surface from the initial position along the operating direction, an initial force is required. If a force smaller than the initial force were exerted on the operating surface starting from the initial position, the operating surface would not shift but would remain at the initial position. In order to thus shift the operating surface in the direction of the operating direction at all, a force is required which is at least as high as the initial force. However, the electrical switching does not take place at the initial force (i.e. while the initial force is thus exerted on the operating surface along the operating direction) but rather at the exertion of a second force which is smaller than the initial force. Before the shifting is performed with the application of the second force, it may be necessary to shift the operation surface by a certain amount (a second amount) from the initial position. The operating surface can be, for example, a surface adapted to the ergonomy of the finger, which can, for example, prevent a finger from slipping off, in particular due to a specific surface characteristic, in order, for example, to increase a roughness. The operating element can be designed in particular in such a way that a displacement of the operating surface transversely to the operating direction is prevented or at least would require forces of such a magnitude that the operating element (or further elements, such as a housing or a guide) would be destroyed or at least damaged when such high forces are exerted. The operating element can thus be designed in such a way that the operating surface is designed for displacement in exactly one direction, i.e. the operating direction, and displacements transversely to the operating direction are prevented.The control element may comprise various elements for applying or generating opposing forces (which counteract a force exerted by the user), which counteract, for example, the initial force in the initial position and the second force in a shift position. Examples include, for example, one or more springs, in particular spiral spring, leaf spring, magnetic elements, for instance permanent magnets or electromagnets, deformable materials, for instance silicone and / or rubber or the like. In particular, different elements can cooperate in order to achieve a prestress such that, starting at the initial position, the initial force is required in order to displace the operating surface along the operating direction.Since the initial force is larger than the second force, backlash of elements of a switch including the operation member can be reduced, whereby a switching operation can be performed more accurately. Furthermore, a shift process that has taken place is clearly perceptible to a user of the operating element.According to one embodiment of the present invention, during the displacement of the operating surface, a first switching contact element is displaced relative to a second switching contact element, wherein the switching takes place during a displacement of the operating surface relative to the second switching contact element by (starting from the initial position) a second distance. The first switching contact element and the second switching contact element can comprise electrically conductive materials and, when the first switching contact element and the second switching contact element are electrically contacted, the switching can take place, wherein an electrical current can flow from the first switching contact element to the second switching contact element, or vice versa.A displacement of the operating surface by the second distance does not necessarily have to correspond to a displacement of the first switching contact element toward the second switching contact element in order to generate an electrical contact between the first switching contact element and the second switching contact element. In particular, the control surface therefore does not have to be connected to the first switching contact element in a completely rigid or non-deformable manner. Rather, the operating element can have at least one deformable element or a deformable component (e.g. a switching mat, rubber or silicone or other plastics), which is at least partially deformed when a force (for example the initial force) is exerted, such that in particular a displacement of the first switching contact element relative to the second switching contact element is smaller or smaller than a displacement of the operating surface relative to the second switching contact element. If the first switching contact element has been displaced relative to the second switching contact element by a threshold distance, the first switching contact element can be brought into electrical contact with the second switching contact element abruptly, if, for example, a spontaneous deformation of a snap disc takes place. Therefore, there may be a non-linear relationship between the displacement of the operating surface relative to the second switching contact element and the displacement of the first switching contact element relative to the second switching contact element. Due to the prestress, which leads to the initial force being greater than the second force, the second travel distance can be relatively small, so that only a short stroke can be required for switching via the operating element. As a result, the switching characteristic can be improved and more precise.According to one embodiment of the present invention, the second distance is between 0.2 mm and 1 mm, in particular between 0.4 mm and 0.8 mm. Thus, a short stroke can be achieved, which can reduce a size and improve shifting. The initial force can be in particular between 2 N and 10 N, further in particular between 3 N and 8 N. Thus, a significant bias may be provided in the initial position, which may in particular reduce inadvertent actuation of the shift. Play can also be reduced.Furthermore, in the case of a displacement of the operating surface between a first distance and the second distance, a greater change in the force per distance can take place than in the case of a displacement of the operating surface between the initial position and the first distance. Thus, a slight change in a displacement required force between the initial position and the first position, which is displaced by a first distance relative to the initial position, may be provided. Thus, the shifting can be more precisely performed and the operation of the shifting can be more securely perceived by a user. Furthermore, the force required for displacement between the initial position and the first travel distance may be constant, (slightly) increase or (slightly) decrease. The increase and / or decrease can be in particular between 0% and 20%, in particular between 5% and 10%.According to one embodiment of the present invention, the first distance is 5% to 15% smaller than the second distance. Between the first path and the second path, a relatively strong change in the force necessary for displacement can be felt by a user, which can improve feedback and haptics. Furthermore, the first force can be equal to the initial force or between 2% and 20%, in particular between 5% and 10%, smaller or greater than the initial force. Thus, upon actuation of the operating element, the user can only feel a slight force change during displacement between the initial position and the first position. However, the second force may be between 5% and 50% smaller or larger than the first force, so that feedback that a shift has occurred may be clearly perceptible to a user.According to embodiments of the invention, the second force may be less than the first force, and in other embodiments, the second force may be greater than the first force. However, due to a relatively large difference between the first force and the second force, the shift operation may be clearly noticed by the user. The second force can be an absolute minimum of a force displacement characteristic of the operating surface, wherein a displacement distance of the operating surface can be plotted against a force required for displacement in the force displacement characteristic. The force-displacement characteristic can be defined or definable in particular by a two-dimensional graph, a table, a mathematical function or the like.In the case of a displacement of the operating surface between the second travel distance and an (even greater) third travel distance, a force required for this purpose can increase in order to correspond to a third force in the third travel distance, which is equal to the first force. In this case, in particular the third distance can be between 5% and 15% greater than the second distance. The third distance can correspond to a third position of the operating surface which is reached after the second position at which the shifting is effected has been passed through, wherein a pressure point can thus be reached at the third position, which pressure point can indicate to the user that the shifting is now completely concluded.In a comparative example, the second force at the second travel distance is a local maximum of a force-displacement characteristic, wherein, when the operating surface is displaced between the second travel distance and a further travel distance, the force required for this purpose drops (starting from the local maximum) and increases between the further travel distance and a fourth travel distance to a fourth force which is equal to the initial force. In this embodiment, the fourth force thus corresponds to a final pressure point of the operating element, which can indicate to the user that the shift that took place at the second position (the second force) is now completely concluded. The further distance (between the second position and the fourth position) can be in particular between 5% and 15% greater than the second distance. Thus, a relatively fast or steep increase in the force beyond the further distance can occur.According to one embodiment of the present invention, the operating element further comprises a switching mat, in particular a silicone switching mat, which is displaced when the operating surface is displaced and by means of which the first switching contact element is displaced. Furthermore, the operating element can have an element for prestressing the switching mat, in particular a spring. The switching mat can have, for example, liquid silicone rubber (LSR) (dt.: liquid silicone), wherein typical constituents of an LSR silicone rubber can have: linear siloxanes: about 70%; fillers: about 30%; additives: about 1%. Other materials or compositions may be provided. The rubber can in particular include silicone. The switching mat can be arranged in particular between the operating surface and the first switching contact element.The spring may be provided to bias the switching mat such that the initial force is required for an initial displacement of the operating surface starting from the initial position. The operating element can thus be produced in a simple manner.The operating element can furthermore have a snap element, in particular a snap disk, wherein the switching mat rests with a side facing away from the operating surface on the snap element in order to enable a force to be transmitted or a force to the snap element exerted on the operating surface. In this case, the first switching contact element can be connected in particular to the snap-on element in order to make electrical contact with the first switching contact element with the second switching contact element during switching.The snap element can have a stable and a metastable state. If the snap-action element is deformed beyond a threshold distance, the snap-action element can transition from the stable state into the metastable state (which causes a displacement of the first switching contact element relative to the second switching contact element) without requiring a further exertion of force. For example, the snap element can be bent or deformed to a certain extent until it suddenly passes through or assumes the metastable state as a result of a bulge. At this point, a sudden jump-over may occur. If the force decreases again, a return to the stable state can take place. A snap-action disc can be inserted in particular in a pushbutton switch.According to one embodiment of the present invention, a switch having an operating element according to one of the embodiments described above is provided, wherein the second switching contact element is arranged in particular on a circuit board.The snap-action disc can comprise, for example, an embossed steel spring which, starting from a stable state, snaps over into the metastable state when deformed beyond a threshold distance. The operating element can be used in particular in a switch for a vehicle. According to one embodiment of the present invention, a vehicle, in particular an automobile, having a switch according to one embodiment of the present invention is provided.Embodiments of the present invention will now be explained with reference to the accompanying drawings. The invention is not limited to the illustrated or described embodiments. Reference numerals in the claims do not limit the scope of the present invention. FIG. 1 shows a schematic sectional view from the side of a switch according to an embodiment of the present invention with an operating element according to an embodiment of the present invention; FIG. 2 shows a force-displacement characteristic of an operating element according to an embodiment of the present invention; FIG. 3 shows a force-displacement characteristic of an operating element according to a further embodiment of the present invention; FIG. 4 shows a force-displacement characteristic of an operating member according to still another embodiment of the present invention; and FIG. 5 shows a force-displacement characteristic of an operation member according to a comparative example of the present invention.The switch 100 of FIG. 1 comprises an operating element 101 according to an embodiment of the present invention. The operating element 101 has an operating surface 103 which is displaceable by applying force to a finger (or any other extremity of a user) 105. The control surface 103 represents a surface of a cover or an actuator 107, which is accessible from the outside. The operating surface 103 is displaceable in an operating direction 109 which is oriented, for example, perpendicularly to the operating surface 103. The operating element 101 further comprises a switching mat 111 which is deformed and displaced during the displacement of the operating surface 103. A first switching contact element 113 belonging to the switch 100 is moved by means of the switching mat 111 towards a second switching contact element 115 when the operating surface 103 is moved. The operating element 101 further comprises a spring 117 with which the switching mat 111 is prestressed by applying a prestress S to the cover 107, which prestress e.g. partially compresses the switching mat 111. By biasing S, it is necessary to apply an initial force F 0 to the operating surface 103 to displace the operating surface 103 (e.g., relative to, in particular, the second switching contact element 115 or the circuit board 119). The switch 100 further comprises a circuit board 119 on which the second switching contact element 115 is arranged. The operating element 101 further comprises a snap disc 121, wherein the switching mat 111 abuts the snap disc 121 with a side 123 facing away from the operating surface in order to enable a force exerted on the operating surface 103 to be transmitted to the snap element or the snap disc 121. In this case, the first switching contact element 113 is connected to the snap-action disc 121 in order to electrically contact the first switching contact element 113 with the second switching contact element 115 for switching purposes.The operating surface 103 can be displaced along a path s starting from an initial position s 0 along the operating direction 109. An initial force F 0 is required for displacement starting from the initial position s 0, a first force F 1 is required for displacement starting from a first distance s 1, a second force F 2 is required for displacement starting from a second distance s 2, and a third force is required for displacement starting from a third distance s 3, as is illustrated by way of example in the following FIGS. 2 to 5. The switch 100 has a housing, not illustrated in FIG. 1, and a base body 125.When the operating surface 103 has been displaced by the second distance s 2, the snap disc 121 has been deformed such that the first switching contact element 113 has been displaced by a distance Δs, which corresponds to a threshold value displacement at which the snap disc 121 is transferred into a metastable state which comprises a further deformation (spontaneous deformation) of the snap element 121 such that the first switching contact element 113 is displaced overall by a distance Δsk in order to come into contact with the second switching contact element 115. The switching operation thus takes place as soon as the operating surface 103 is displaced by the second distance s 2, as a result of which a contact closure is produced between the first switching contact element 113 and the second switching contact element 115. It should be noted here that both the threshold value displacement Δs and the effective displacement Δsk of the first switching contact element 113 relative to the second switching contact element 115 can be unequal (in particular smaller) than the second travel distance s 2 and is generally. The snap disc 121 may have a curved (e.g. convex) shape in the stable (initial state) state and may have a reversely curved (e.g. concave) shape after being snapped into the metastable state. The switching mat 111 may enclose the snap disc 121 (together with the circuit board 119) and may have a shape similar to, but somewhat larger than, the snap disc. In a central region 114, the circuit mat 111 can contact the snap disc 121. A (e.g. circular) edge 122 of the snap disc 121 can contact the circuit board 119 or rest there.Instead of using a finger 105, the user interface 103 can also be moved by another object. The total switching stroke (the distance s 2) can be kept relatively small by the prestress by means of the spring 117 (and / or the switching mat 111 and / or further elements). In conventional operating elements, for example, the initial force F0may be substantially smaller than the second force F2. The short actuation path (second path length s 2) furthermore also allows a gap size or gap size between the cover 107 and a housing or a guide, not illustrated in FIG. 1, to be advantageously reduced, such that in particular a play of the operating element 101 or of a switch 100 equipped therewith can be reduced. By means of different spring characteristics of the spring 117 and corresponding configuration of the switching mat 111 (in shape and in material), the force-displacement characteristics illustrated and described below in FIGS. 2 to 5 can be realized. In other embodiments, a different element may be provided instead of the snap disc 121. For example, a surface 123 of the switching mat 111 facing away from the operating surface 103 could be connected to the first switching contact element 113 without the snap disc 121 being arranged therebetween. One or more springs may be disposed between the snap disc 121 and the circuit board 119 in other embodiments to achieve a desired force-displacement characteristic as illustrated in Figures 2-5. The body 125 may also represent a portion of a housing or a support member. The spring 117 can be designed, for example, as a helical spring, as an omega spring or as another spring. The cover 107 can also be designed as an actuator.FIGS. 2, 3 and 4 illustrate force-displacement characteristics 200, 300 and 400 according to embodiments of the invention by curves 202, 303, 402, wherein a second force F 2 drops during a shift in a second position P 2. In contrast, FIG. 5 illustrates, by curve 502, a comparative example of a force-displacement characteristic 500 in which, upon a shift at position P 2, a force F 2 required for this purpose increases to a local maximum.FIGS. 2-5 show, on respective abscissas 201, 301, 401, and 501, a distance s representing a displacement distance of the user interface 103 starting from an initial position s 0. The force is plotted on the ordinate 203, 303, 403 and 503 in each case, which force is required for displacement starting from a specific distance by which the operator interface 103 has already been displaced. It should be noted that the force-displacement characteristics illustrated in FIGS. 2-5 may only apply in the direction in which the operating surface 103 is displaced along the operating direction 109 for switching, but may look different for the reverse path (opposite the operating direction 109), as some hysteresis may be provided, or may look the same if no hysteresis is present.In FIG. 2, the operation surface 103 at the travel distance s 0 is at the initial position P 0. In order to shift the operating surface 103 from the initial position P 0 in the direction of the operating direction 109, an initial force F 0 is required. In FIG. 2, the force required to move between the initial position and a first position P 1 (first travel distance s 1) is constant and thus equal to F 0, which is also equal to the first force F 1 required in the first position P 1 (travel distance s 1). Between the first position P 1 and the second position P 2, at which a shift is effected (second travel distance s 2), the force decreases from the first force F 1 to a second force F 2. As can be seen, in the displacement-force characteristics of FIGS. 2-4, the second force F2 is smaller than the initial force F0, respectively. In FIG. 2, the force required for further displacement of the operating surface 103 beyond the second position P 2 increases in order to achieve the force F 3 which is equal to the first force F 1 at a third position P 3 (third distance s 3).Furthermore, a force-displacement curve is illustrated as dashed line 204 in FIG. 2, which would be shown by an operating element in which no prestress S (cf. FIG. 1 ) is applied. At the dashed line, an initial force typically increases from 0 N as the non-biased surface displaces to achieve the force F0after a certain displacement, which is the initial force according to these embodiments of the present invention. The force-displacement characteristic 204 may be observed in conventional controls, wherein the relatively weak initial force may result in inaccurate actuation and also inaccurate shifting.According to embodiments of the present invention, the characteristics illustrated in FIGS. 2, 3 to 4 may have target values as follows:F03N - 8NS00 mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mmSnap ((F1-F2) / F1)*100%5% - 50%S2 (shift point)0.4 mm - 0.8 mmS1XX% S2S3YY% S2F3F1Here, XX is a factor of less than 100, and YY is a factor of greater than 100.In contrast to the constant force F 0=F 1 between the initial position and the first position P 1 in FIG. 2, the force in the characteristic 300 in FIG. 3 slightly increases and the force in the characteristic 400 in FIG. 4 slightly decreases.Characteristic of the force-displacement characteristics of Figures 2, 3 and 4 is a significant bias F0 at point P0 and a relatively small change in force between the initial position P0 and the first position P1, i.e. a small change in forces F0 and F1. The small change in force F0and F1may also be sufficient in the region of the prestress (<s0) to keep the force F0between operating elements as constant as possible on account of the mechanical tolerances of the operating elements. Beyond the first position P 1, the haptic feedback or the haptic feedback for the user takes place up to the second position P 2 by means of snap and path. The exact changes of the forces F 0, F 1, F 2 and F 3 and of the positions P 0, P 1, P 2 and P 3 or travel distances s 0, s 1, s 2, s 3 can be adapted to application-specific requirements and are in principle variable. Optionally, acoustic feedback can be output for haptic feedback. The defined slope between the second position P2 and the third position P3 may be a final significant range of the new force-displacement characteristics. The exact path change s3=x*s2(x is a factor greater than one) can be variable and defined according to requirements. A fixed condition can be the equation F3=F1, and the mechanical stop can take place later.FIGS. 2-4 each show a force-displacement curve of the operating element and not of individual actuators, wherein the tolerances can be variable.FIG. 5 shows a force-displacement characteristic, wherein when shifting to the second position P 2, the force increases to a local maximum to assume the value F 2.Characteristic of the force-displacement characteristic 500 as well is a significant bias voltage F 0 in the initial position P 0. Furthermore, the actuator system can have a small force change in the region around F0 in order to keep the force F0 between operating elements as constant as possible on account of the mechanical tolerances of the operating elements. Between the initial position P 0 and the first position P 1 (distance s 1), the force decreases from the initial force F 0 to the first force F 1. The second force that is reached at the second position P 2 (second travel distance s 2) is smaller than the initial force F 0. Beyond the first position P 1 to P 2, the haptic feedback takes place by means of snap (force change in percent) and path. The exact values of the forces and travel distances can be defined in an application-specific manner. The defined slope between the further position Pw (at the further position sw) and the fourth position P 4 (at a fourth distance s 4) can be the last significant region of the new haptics. The exact path change s4=x*s2(x is a factor greater than one) can later be defined in an application-specific manner and can basically be variable. A fixed condition may be the equation F4=F0and the mechanical stop may occur later.According to the comparative example, the following target values may apply to the characteristic illustrated in FIG. 5 :F03N - 8NS00 mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mmSnap ((F1-F2) / F1)*100%5% - 50%S2 (shift point)0.4 mm - 0.8 mmS1XX% S2S4YY% SwF4F0Here, XX is a factor of less than 100, and YY is a factor of greater than 100.List of reference characters100 Switch 101 Operating element 103 Operating surface 105 Finger 107 Cover 109 Operating direction 111 Circuit mat 113 First switching contact element 115 Second switching contact element 117 Spring 119 Circuit board 121 Snap disc 123 Part of the circuit mat 125 facing away from the operating surface Switch body s Distance F Force s0, s1, s2, s3, sw, s4 Initial distance, first, second, third, further, fourth distance F0 Initial force F1, F2, F3, Fw, F4 First, second, third, further, fourth force P0 Initial position P1, P2, P3, P4 First, second, third, fourth position Pw Further position 201 - 501 Abscissas 203 - 503 Ordinates 200 - 500 Force-displacement characteristics 202 - 502 Force-displacement curves

Claims

Operating element (101) for electrical switching, comprising: an operating surface (103) displaceable by applying force by means of a finger (105), wherein the operating surface (103) is displaceable starting from an initial position (P0) under application of an initial force (F0), wherein the switching is effected under application of a second force (F2) which is smaller than the initial force (F0), wherein a greater change in the force per distance takes place when the operating surface (103) is displaced between a first distance (s1), at which a first force (F1) is required, and the second distance (s2) than when the operating surface (103) is displaced between the initial position (P0) and the first distance (s1), wherein the force required for displacement between the initial position (P0) and the first travel distance (s1) is constant, increases or decreases.Operating element according to Claim 1, wherein, when the operating surface is displaced, a first switching contact element (113) is displaced relative to a second switching contact element (115), wherein, when the operating surface is displaced relative to the second switching contact element, the switching takes place by a second distance (s2), starting from the starting position (P0).Operating element according to Claim 1 or 2, wherein the second distance (s2) is between 0.2 mm and 1 mm, in particular between 0.4 mm and 0.8 mm, wherein the initial force (F0) is in particular between 2 N and 10 N, further in particular between 3 N and 8 N.Operating element according to Claim 3, wherein the first distance (s1) is 5% to 15% smaller than the second distance (s2), wherein in particular the first force (F1) is equal to the initial force (F0) or is between 2% and 20%, in particular 5% and 10%, smaller or larger than the initial force (F0), wherein in particular the second force (F2) is between 5% and 50% smaller or larger than the first force (F1).Operating element according to Claim 4, wherein the second force (F2) is an absolute minimum of a force-displacement characteristic (200, 300, 400) of the operating surface (103), wherein, in the case of a displacement of the operating surface (103) between the second path distance (s2) and a third path distance (s3), a force required therefor in particular increases in order to correspond, in the case of the third path distance (s3), to a third force (F3) which is equal to the first force (F1), wherein the third path distance (s3) is in particular 5% to 15% greater than the second path distance (s2).Operating element according to Claims 1 to 4, wherein the second force (F2) at the second travel distance (s2) represents a local maximum of a force-displacement characteristic (500), wherein, when the operating surface is displaced between the second travel distance (s2) and a further travel distance (sw), the force required for this purpose drops to a further force (Fw) and increases between the further travel distance (sw) and a fourth travel distance (s4) to a fourth force (F4) which is equal to the initial force (F0), wherein the further travel distance (sw) is in particular 5% to 15% greater than the second travel distance (s2).Operating element according to one of the preceding claims, further comprising: a switching mat (111), in particular a silicone switching mat, which is deformed and / or displaced when the operating surface (103) is displaced and by means of which a first switching contact element (113) is displaced; and an element (117) for prestressing the switching mat (111), in particular a spring.Operating element according to Claim 7, further comprising: a snap-action element (121), in particular a snap-action disc, wherein the switching mat (111) bears with a side (123) facing away from the operating surface (103) against the snap-action element (121), in order to enable a force exerted on the operating surface (103) to be transmitted to the snap-action element (121), wherein in particular the first switching contact element (113) is connected to the snap-action element (121), in order to contact the first switching contact element (113) electrically with the second switching contact element (115) during switching.

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