Device for detecting a key press and / or a travel distance of a key module, keyboard

Abstract

Device (10) for detecting a key press and / or a travel distance of a key module (11) comprising a circuit substrate (18), a coil (30) arranged on or in the circuit substrate (18), a keypad module (11) attached to the circuit substrate (18) with a housing (12), with a movement mechanism (15) comprising a plunger (16) and a return spring (17) and with a damping element (19) for changing the inductance and / or for changing a physical quantity of the coil (30), wherein the plunger (16) is movable relative to the housing (12) between a rest position and an actuating position, wherein the damping element (19) is movable relative to the housing (12) and arranged such that a movement of the damping element (19) causes a change in inductance and / or a change in a physical quantity of the coil (30), wherein the damping element (19) is coupled to the plunger (16) such that the movement of the damping element (19) originates from a movement of the plunger (16), wherein a movement of the plunger (16) from the rest position towards the actuation position, due to the coupled movement of the damping element (19), causes a change in inductance and / or a change in a physical quantity of the coil (30), wherein the device (10) outputs at least one electrical signal to signal the key actuation and / or the actuation path of the key module (11) during the change in inductance and / or change in the physical quantity of the coil (30), characterized by that the damping element (19) is mounted on the housing (12) and / or on the circuit substrate (18), that the mobility of the damping element (19) relative to the housing (12) is a rotational mobility or a linear mobility parallel to the circuit substrate (18), and that the damping element (19) is coupled to the plunger (16) in such a way that a rotational or linear movement of the damping element (19) causing the change in inductance and / or the change in the physical size of the coil (30) deviates from the movement of the plunger (16).

Description

[0001] The invention relates to a device for detecting a key press and / or the actuation path of a key module and a keyboard comprising one or more such devices. Key modules are a central component of keyboards.

[0002] Inductive keypad modules are known. These have a damping element that approaches a planar coil when the keypad module is pressed. The resulting change in inductance is detected and signals the actuation of the keypad module.

[0003] Such key modules are known from DE 10 2020 127 246 A1, DE 10 2020 132 195 A1, DE 10 2020 132 198 A1, DE 10 2021 116 021 A1, DE 10 2020 132 196 A1, DE 10 2015 120 607 A1, DE 10 2015 204 440 A1 and US 2010 / 0320066 A1.

[0004] The familiar key modules have the disadvantage that the damping elements are attached to the plungers. While the implementation is very simple, it brings with it three major drawbacks: 1. The damping element is directly coupled to the plunger as the actuator and thus travels the same distance as the plunger. This is typically 3 to 4 mm. Due to the available installation space, the magnetic field of the coil is relatively shallow. As a result, the damping element is partially or completely outside the magnetic field in its rest position. This significantly reduces or eliminates the magnetic field coupling between the planar coil and the damping element in the rest position. This makes the detection of signal changes inaccurate and sometimes even impossible. 2. The magnetic field strength of the coil decreases disproportionately and therefore non-linearly with distance from the coil or the circuit board containing the coil. Since the plunger with the damping element moves linearly towards or away from the coil, the damping of the coil is highly non-linear. This results in a very uneven inductance-displacement curve. When the damping element moves from its rest position towards the coil, accurate signal acquisition is impaired in the first half of the travel distance. When the damping element moves from its rest position away from the coil, signal acquisition deteriorates in the second half of the travel distance. In both cases, linear signal-displacement acquisition is not possible. While it is possible to improve linearity by converting the counts during signal processing, this leads to increased inaccuracy in the switching paths and / or increases the cost of the final product.

[0005] Keyboards based on Hall sensors, capacitive sensors, and optical sensors have similar problems.

[0006] 3. The implementation of key modules with a linear force-displacement characteristic is known. However, the implementation of tactile key modules (with a tactile force-displacement curve) or clicking key modules (with tactile and acoustic feedback) has so far been complicated and / or only possible with the aid of additional mechanisms. A fixed coupling between the tactile or click-tactile point and the electrical switching point is not possible or at least highly dependent on tolerances.

[0007] The invention is therefore based on the objective of providing a new device for detecting a key press and / or an actuation path of a key module, in particular a device that at least partially overcomes the aforementioned disadvantages. Furthermore, a keyboard comprising one or more such devices is to be provided.

[0008] This problem is solved with respect to the device by a device having the features of claim 1 and with respect to the keyboard by a keyboard having the features of claim 24. Advantageous embodiments and further developments are specified in the dependent claims.

[0009] The device according to the invention for detecting a key actuation and / or an actuation path of a key module comprises a circuit substrate, for example a printed circuit board, and a coil arranged on or in the circuit substrate, in particular a planar coil.

[0010] The device further comprises a keypad module attached to the circuit substrate, with a housing, a movement mechanism comprising a plunger and a return spring, and a damping element for changing the inductance and / or a physical quantity of the coil, wherein the plunger is movable relative to the housing between a rest position and an actuation position.

[0011] The damping element is movable relative to the housing and arranged in such a way that a movement of the damping element causes a change in inductance and / or a change in a physical quantity of the coil.

[0012] The damping element is coupled to the plunger in such a way that the movement of the damping element originates from a movement of the plunger. A movement of the plunger from its rest position towards the actuation position causes a change in inductance and / or a change in a physical property of the coil due to the coupled movement of the damping element. Upon this change in inductance and / or change in the physical property of the coil, the device outputs at least one electrical signal to indicate the button actuation and / or the actuation path of the key module.

[0013] The invention provides that the damping element is mounted on the housing and / or the circuit substrate. The damping element's mobility relative to the housing is either rotational or linear, parallel to the circuit substrate. The damping element is coupled to the plunger in such a way that any rotational or linear movement of the damping element that causes a change in inductance and / or a change in the physical properties of the coil deviates from the movement of the plunger.

[0014] The advantages of the invention lie particularly in the fact that the damping element is not directly attached to the plunger as the actuator of the keypad module and therefore does not have to travel the same path as the plunger. Rather, the plunger and damping element are decoupled in such a way that the damping element is also moved by the movement of the plunger, but the paths of movement of the plunger and the damping element differ. The movements diverge from one another: the linear movement of the plunger perpendicular to the circuit substrate is opposed to a rotational movement or a linear movement of the damping element, with the linear movement of the damping element being parallel to the circuit substrate. Furthermore, the transmission of motion from the plunger to the damping element need not be linear and / or proportional; a non-linear and / or non-proportional transmission is also possible.

[0015] To couple the movement of the damping element to the movement of the plunger, a transmission mechanism, such as a variable gear, is required. This makes it possible to both define an arbitrary motion transmission coefficient and to vary the motion transmission coefficient as desired during actuation.

[0016] A rotary mounting and movement of the damping element offers advantages in terms of simple technical design, accuracy, reliability, cost, and durability. However, linear movement of the damping element parallel to the circuit substrate can also prove advantageous with appropriate, particularly spatial, design of the key modules.

[0017] A damping element is understood to be, in particular, an element that, when placed in the magnetic field of a coil and / or when moving within the magnetic field of a coil, changes the inductance of the coil. This process is referred to as "damping" or "attenuation" of the coil.

[0018] A further development of the invention provides that an opposing movement of the plunger from the actuating position towards the rest position, due to the coupled movement of the damping element, also causes a change in inductance and / or a change in a physical quantity of the coil, wherein the device outputs at least one electrical signal to signal the release of the button, i.e., the return to the rest state due to the return spring of the plunger, when the inductance and / or the physical quantity of the coil changes.

[0019] According to one embodiment, the damping element can be rotatable about an axis of rotation that runs parallel to the circuit substrate, specifically to the surface of the circuit substrate.

[0020] The rotational mounting of the damping element on the housing of the key module can be achieved by inserting at least two opposing lateral projections formed on the damping element into recesses in the housing.

[0021] It can be provided that the damping element is rotatably mounted via at least two projections formed on the damping element and extending towards the circuit substrate. These projections extend through a continuous recess in the housing and rest against the circuit substrate. The projections thus protrude through the housing and bear against the surface of the circuit substrate. This compensates for the mounting tolerances of the keypad module relative to the circuit substrate in the perpendicular direction, since the support is not located within the keypad module housing but directly on the circuit substrate. The position of the damping element relative to the coil on or within the circuit substrate thus remains constant.

[0022] One embodiment of the invention provides that the damping element has a damping leg and a control leg, which are connected at an angle to each other at one end of the legs. During rotational movement, the damping leg is pivoted towards or away from the coil. During linear movement, the damping leg is displaced parallel to the circuit substrate. The control leg is coupled to the plunger to convert its movement into the rotational or linear movement of the damping element.

[0023] The aforementioned coupling between the plunger and the control arm of the damping element can be achieved by the control arm bearing against the plunger, the plunger having a guide profile that interacts with a control profile of the control arm. As the plunger moves, the control profile of the control arm slides along the guide profile of the plunger, thereby causing the damping arm to rotate towards or away from the coil, or to move linearly parallel to the circuit substrate.

[0024] Furthermore, a return spring may be integrated and / or arranged and / or attached in or on the control arm of the damping element, wherein the return spring of the damping element is pre-tensioned against the housing of the key module and, due to its pre-tension, ensures that the control profile of the control arm rests against the guide profile of the plunger. If the return spring is a separate spring that is arranged and / or attached to the control arm of the damping element, the separate spring may, for example, be designed as a bending spring, compression spring, tension spring, or torsion spring.

[0025] Additionally, it may be provided that the control profile of the control arm includes a control cam that protrudes towards the guide profile of the tappet.

[0026] One embodiment of this provides that the motion translation from the movement of the plunger into the rotational movement of the damping arm is determined by the shape of the plunger's guide profile.

[0027] Furthermore, it can be provided that the guide profile on the plunger decreases at least section by section, contrary to the intended actuation movement of the plunger, so that a constant plunger movement in the actuation direction, as the control cam slides along the constantly decreasing section of the guide profile, results in a constant angular velocity of the rotational movement of the damping arm towards the coil. It can also be provided that the guide profile on the plunger decreases at least section by section, progressively lessening, contrary to the intended actuation movement of the plunger, so that a constant plunger movement in the actuation direction, as the control cam slides along the progressively lessening section of the guide profile, results in a decreasing angular velocity of the rotational movement of the damping arm towards the coil.It can also be provided that the guide profile on the plunger increases at least section by section, contrary to the intended actuation movement of the plunger, so that a constant plunger movement in the actuation direction, as the control cam slides along the constantly increasing section of the guide profile, results in a constant angular velocity of the rotational movement of the damping arm away from the coil. Furthermore, it can be provided that the guide profile on the plunger increases at least section by section, progressively less, contrary to the intended actuation movement of the plunger, so that a constant plunger movement in the actuation direction, as the control cam slides along the progressively less increasing section of the guide profile, results in a decreasing angular velocity of the rotational movement of the damping arm away from the coil.

[0028] One embodiment provides that the guide profile on the plunger forms a projection, so that during a planned actuation movement of the plunger, the control cam slides up to a vertex of the projection against an increasing force of the return spring of the damping element, which requires an increasing force when actuating the plunger, which ceases after passing the vertex of the projection, so that passing the vertex of the projection simultaneously causes a tactilely perceptible pressure point effect and a sudden change in the direction of the rotational movement of the damping arm and thus a comparatively strong change in inductance and / or a change in a physical quantity of the coil.

[0029] A further development of the aforementioned embodiment provides that the plunger comprises a main body, which executes the plunger's movement, and a moving element. The main body has a bottom surface facing the circuit substrate and a top surface opposite the bottom surface. Laterally, between the bottom surface and the top surface, a recess is provided into which the moving element is inserted and rotatably mounted on the bottom of the recess, opposite an opening of the recess, about an axis of rotation perpendicular to the intended direction of movement of the main body. The recess defines a space of movement for the moving element, with an upper stop on the top surface of the main body and a lower stop on the bottom surface of the main body, within which the moving element can rotate between the upper and lower stops.The moving body forms at least part of the guide profile for the plunger, with the guide profile forming a projection in the area of ​​the moving body and a recess on the side of the projection facing the underside of the main body. In the plunger's rest position, the moving body rests against the lower stop, and the control cam rests in the recess on the moving body. When the plunger moves from the rest position toward the actuating position, the moving body is initially moved toward the upper stop, and the control cam remains in the recess on the moving body. With further movement of the plunger, the moving body initially rests against the upper stop, and the control cam slides out of the recess to the apex of the projection, and then the control cam passes over the apex of the projection.In this process, the moving body is abruptly moved to the lower stop, thereby creating a striking noise, and the damping leg is moved towards the coil.

[0030] The embodiment described above has the advantage that passing the apex of the projection not only simultaneously causes a tactilely perceptible pressure point effect and a sudden change in the direction of the damping arm's rotation, resulting in a comparatively strong change in inductance and / or a change in a physical property of the coil, but also simultaneously generates an impact noise that provides the operator of the keypad module with acoustic feedback of the actuation. The advantages of the aforementioned refinement lie particularly in the fact that the moving element is mounted exclusively on the main body of the plunger and does not come into contact with other housing parts of the keypad module. Furthermore, the moving element is rotatably mounted within the main body and can complete its rotational movement within the movement space of the main body.Since the rotational movement is small and the axis of rotation generates relatively little friction anyway, the overall friction balance is very positive. Compared to other known key modules, this key module thus provides a defined and therefore improved click sound when pressed. A further advantage is that the strong induction change is accompanied by tactile and audible feedback, meaning that a switching and / or signaling process detected by the induction change, which is then transmitted to a computer, for example, is simultaneously perceptible to the operator both tactilely and audibly.

[0031] The intensity of the impact noise depends on the rotation angle of the moving body and / or its weight and / or the position of the impact surfaces and / or the spring force of the damping element's return spring, and can be adjusted by selecting these parameters accordingly. Furthermore, the pre-travel distance or force-displacement curve when the key module is actuated can be adjusted by the rotation angle and the guide profile of the moving body.

[0032] As an alternative to the aforementioned configurations with a control cam on the control profile of the control arm, it can also be provided that the guide profile of the plunger includes a sliding cam that projects towards the control profile of the control arm of the damping element. A further development of this provides that the motion transmission from the movement of the plunger to the rotational movement of the damping arm is determined by the shape of the control profile of the control arm.

[0033] For all the above variants, it can be provided that the damping arm has a continuous recess that is laterally enclosed by the material of the damping arm, so that the damping arm represents a secondary coil with a short-circuited coil turn that interacts inductively with the coil as the primary coil. According to one embodiment, the secondary coil can be rotated into or out of the magnetic field of the coil when the plunger moves from the rest position towards the actuating position, thereby causing a change in inductance and / or a change in a physical property of the coil.

[0034] Alternatively, the damping leg can be designed as a plate which, when the plunger moves from the rest position towards the actuating position, is rotated into or out of the magnetic field of the coil, thereby inducing eddy currents in the plate which cause the change in inductance and / or the change in a physical quantity of the coil.

[0035] The damping element can consist of a ferromagnetic, paramagnetic, or electrically conductive material, or at least comprise a ferromagnetic, paramagnetic, or electrically conductive material in certain areas.

[0036] The damping element can be a stamped metal part.

[0037] The movement of the plunger can be a linear movement, a rotational movement, or a contour-controlled movement.

[0038] The keypad module may have integrated backlighting or have its own dedicated backlighting. The backlighting may be mounted on the circuit substrate in such a way that it illuminates an associated keycap with symbols and / or the keypad module housing. One or more light guides may be integrated into the keypad module housing and / or arranged as separate components within the keypad module.

[0039] The keyboard according to the invention comprises one or more devices according to the invention.

[0040] The invention is further explained below with regard to other features and advantages by means of a description of exemplary embodiments and with reference to the accompanying schematic drawings.

[0041] This shows Fig. 1, Fig. 2 to Fig. 3 in various representations a device according to the invention in perspective view, Fig. 4. Three exemplary variants for the design of the plunger of the key module of the device according to Fig. 1, Fig. 5, Fig. 6, Fig. 7 to Fig. 8 in different views a first embodiment of the damping element as it is used in the keypad module of the device according to Fig. 1 can be used, Fig. 9 and Fig. 10. Two perspective exploded views of the device from different angles. Fig. 1 using the in Fig. 4 variant of the plunger shown on the left and using the damping element according to Fig. 5, Fig. 11, Fig. 12 to Fig. 13 in sectional views the device according to Fig. 9 in different states of motion, Fig. 14, Fig. 15 to Fig. 16 in sectional views the device according to Fig. 1 in different states of motion, where here the in Fig. The variant of the pestle shown in the middle is used in section 4. Fig. 17 and Fig. 18 who are in Fig. 4. Variant of the pestle shown on the right in different representations, Fig. 19, Fig. 20, Fig. 21 to Fig. 22 in sectional views of the device according to Fig. 1 in different states of motion, where here the in Fig. 4. Variant of the pestle shown on the right, which is also in Fig. 17 and Fig. 18 is shown, is used, Fig. 23 a second embodiment of the damping element as it is used in the device according to Fig. 1 can be used, Fig. 24 a perspective exploded view of the device according to Fig. 1 using the in Fig. 4 variant of the plunger shown on the left and using the damping element according to Fig. 23, Fig. 25, Fig. 26 to Fig. 27 in sectional views of the device according to Fig. 24 in various states.

[0042] Corresponding parts and components are marked with the same reference symbols in all figures.

[0043] Fig. 1 to Fig. Figure 3 shows an embodiment of a device 10 according to the invention in a perspective view. The device 10 comprises a circuit substrate 18, for example a printed circuit board, and a coil 30 arranged on or in the circuit substrate 18, in the illustrated embodiment a planar coil arranged on a top side of the circuit substrate, as well as a keypad module 11 attached to the circuit substrate 18. The device 10 serves to detect a key press and / or an actuation path of the keypad module 11. Fig. Figure 1 shows the device 10 with a keypad module 11 mounted on the circuit substrate 10. Fig. 2 the key module 11 is lifted from the circuit substrate 18, so that the coil 30, a planar coil which is arranged on the circuit substrate 18, and a light 50, here an LED, can be seen. Fig. Figure 3 shows a cross-sectional view in which the interior of the key module 11 can be seen.

[0044] The keypad module 11 comprises a housing 12, which consists of a first housing part 13, a top part or cover, and a second housing part 14, a bottom part or base. The keypad module 11 further comprises a movement mechanism 15 with a plunger 16 and a return spring 17, wherein the plunger 16 is movable relative to the housing 12 between a rest position and an actuation position.

[0045] Fig. Figure 4 shows three exemplary variants for the design of the plunger 16 of the key module 11. These are described in more detail below in the description of the movement of the plunger 16.

[0046] Fig. 9 and Fig. Figure 10 shows two perspective exploded views of the device 10 from different angles. Fig. 1 using the in Fig. Figure 4 shows the variant of the plunger 16 on the left. It can be seen that the key module 11 also includes a damping element 19, which is designed to change the inductance and / or a physical property of the coil 30. For this purpose, the damping element 19 is movably arranged relative to the housing 12. This movable arrangement within the housing 12 is such that a movement of the damping element 19 causes a change in the inductance and / or a change in a physical property of the coil 30. The movement of the damping element 19 originates from a movement of the plunger 16. To achieve this, the damping element 19 is coupled to the plunger 16, whereby a movement of the plunger 16 from its rest position towards the actuation position, due to the coupled movement of the damping element 19, causes a change in the inductance and / or a change in a physical property of the coil 30. This will be explained in more detail below.The damping element 19 is coupled to the plunger 16 in such a way that a rotational movement of the damping element 19, which causes a change in inductance and / or a change in the physical quantity of the coil 30, deviates from the movement of the plunger 16. This will also be explained in more detail below.

[0047] The device 10 is arranged such that, in the event of a change in inductance and / or a change in the physical size of the coil 30, as mentioned above, it outputs at least one electrical signal to signal the actuation of the key and / or the actuation path of the key module 11.

[0048] A reverse movement of the plunger 16 from the actuation position towards the rest position also causes a change in inductance and / or a change in a physical quantity of the coil 30 due to the coupled movement of the damping element 19. Here too, it can be provided that the device 10 outputs at least one electrical signal to signal the release of the button when the inductance and / or the physical quantity of the coil 30 changes.

[0049] In Fig. 9 and Fig. Figure 10 shows the embodiment of the damping element 19 as a first embodiment of the damping element 19, which is in Fig. 5, Fig. 6, Fig. 7 to Fig. 8 is shown in isolation.

[0050] Fig. 5, Fig. 6, Fig. 7 to Fig. Figure 8 shows in various views the aforementioned first embodiment of the damping element 19, as it can be used in the key module 11. This first embodiment is described in the following. Fig. 9 to Fig. 16 and Fig. 19 to Fig. 22 devices 10 and key modules 11 shown are used. Fig. Figure 23 shows a second embodiment of the damping element 19 in isolation. This second embodiment is described in the Fig. 24 to Fig. The damping element 19 is used in the devices 10 and key modules 11 shown in Figure 27. The first embodiment of the damping element 19 is mounted on the housing 12, the second embodiment of the damping element 19 is mounted on the circuit substrate 18.

[0051] In both embodiments, the damping element 19 has a damping leg 20 and a control leg 21, which are connected at an angle to each other at one end of the two legs 20, 21.

[0052] The two embodiments shown are designed such that the damping leg 20 of the damping element 19 inserted into the key module 11 is pivoted towards or away from the coil 30 by a rotational movement, i.e. the mobility of the damping element 19 relative to the housing 12 is a rotational mobility.

[0053] In the first embodiment, the damping element 19 is mounted on the housing 12 of the key module 11 by means of at least two opposing lateral projections 43 formed on the damping element 19, in the example shown laterally on the control arm 21 of the damping element 19, being inserted into recesses 44 in the housing 12 (see Fig. 5 to Fig. 8 as well as Fig. 9 and Fig. 10).

[0054] In the second embodiment, the damping element 19 is mounted on rotation by means of at least two projections 43 formed on the damping element 19, specifically on the control arm 21, and projecting towards the circuit substrate 18, wherein the projections 43 extend through a continuous recess 44 in the housing 12 and bear against the circuit substrate 18. This is evident from Fig. 23 in connection with Fig. 25 and Fig. 26 is evident. Fig. 27 additionally shows the in Fig. 26 Device 10 shown in a section rotated by 90° about a vertical axis.

[0055] This second design has the advantage that the distance between damping element 19, in particular its damping leg 20, and the coil 30 on the circuit substrate 18 is not dependent on the precision of the mounting of the key module 11 on the circuit substrate 18. This is illustrated by Fig. 25 and Fig. 26. In Fig. 25 the key module 11 is mounted on the circuit substrate 18 at a greater distance than in Fig. 26. However, since the damping element 19 is mounted directly on the circuit substrate 18 and not in the housing 12, this difference in distance between the keypad module 11 and thus the housing 12 and the circuit substrate 18 is irrelevant for the distance between the damping arm 20 and the coil 30 on the circuit substrate 18. This distance is the same in both cases. Therefore, the change in inductance and / or the change in a physical property of the coil 30 caused by the movement of the damping arm 20 is independent of the distance between the housing 12 of the keypad module 11 and the circuit substrate, and thus of the precision of the mounting of the keypad module 11 on the circuit substrate 18. Consequently, different keypad modules 11, even when mounted differently on the circuit substrate 18, result in comparable changes in inductance and / or changes in a physical property of the coil 30.

[0056] In both embodiments, the damping element 19 is rotatable about an axis of rotation that runs parallel to the circuit substrate 18.

[0057] The following explanations pertain to both embodiments of the damping element 19. The damping leg 20 has a continuous recess 47 which is laterally enclosed by the material of the damping leg 20, so that the damping leg 20 constitutes a secondary coil 48 with a short-circuited coil winding 49, which interacts inductively with the coil 30 on the circuit substrate 18 as the primary coil. As will be explained in more detail below, this secondary coil 48 is rotated into or out of the magnetic field of the coil 30 when the plunger 16 moves from its rest position towards the actuating position, thereby causing a change in inductance and / or a change in a physical quantity of the coil 30.

[0058] Alternatively to the embodiments shown, the damping leg 20 of the damping element 19 could also be designed as a plate which, when the plunger 16 moves from the rest position towards the actuating position, is rotated into or out of the magnetic field of the coil 30, thereby inducing eddy currents in the plate which cause the change in inductance and / or the change in a physical quantity of the coil 30.

[0059] The following explanations apply to both embodiments of the damping element 19. To convert the movement of the plunger 16 into the rotational movement of the damping element 19, the control arm 21 is coupled to the plunger 16. The coupling between the plunger 16 and the control arm 21 of the damping element 19 is achieved by the control arm 21 bearing against the plunger 16. This is accomplished by a return spring 45 integrated into the control arm 21 of the damping element 19, which, in the illustrated embodiment, is formed integrally with the control arm 21 and the damping arm 20. Alternatively, a different arrangement and / or attachment of the return spring to the control arm 21 is also possible. The return spring 45 of the damping element 19 is biased against the housing 12 of the key module 11. Due to its preload, the return spring 45 of the damping element 19 ensures that the control arm 21 rests against the plunger 16.

[0060] The plunger 16 has a guide profile 34 that interacts with a control profile 35 of the control arm 21. In the illustrated embodiments, the control profile 35 is in two parts. During the movement of the plunger 16, the control profile 35 of the control arm 21 slides along the guide profile 34 of the plunger 16, thereby causing the damping arm 20 to rotate towards or away from the coil 30. Due to its preload, the return spring 45 of the damping element 19 ensures that the control profile 35 of the control arm 21 bears against the guide profile 34 of the plunger 16.

[0061] The control profile 35 of the control arm 21 comprises a control cam 36, which in both embodiments is a two-part control cam 36. The control cam 36 projects towards the guide profile 34 of the plunger 16.

[0062] The motion translation from the movement of the plunger 16 into the rotational movement of the damping leg 20 is determined by the shape of the guide profile 34 of the plunger 16.

[0063] For example, the guide profile 34 on the plunger 16 can decrease continuously, at least section by section, contrary to an intended actuation movement of the plunger 16, so that a constant plunger movement in the actuation direction, as the control cam 36 slides along the continuously decreasing section of the guide profile 34, leads to a decreasing angular velocity of the rotational movement of the damping arm 20 towards the coil 30. For example, the plunger 16 can be adjusted accordingly, as shown in Fig. The 4th variant on the left is executed. Using this variant of the plunger 16, the corresponding sequence of movements is exemplified with the plunger 16 being increasingly pressed into the housing 12 in the intended direction of movement, i.e., from the rest position of the plunger 16 towards the actuation position, in Fig. 11, Fig. 12 and Fig. 13 shown, from the resting position in Fig. 11 via an intermediate position in Fig. 12 up to the actuation position in Fig. 13.

[0064] It can also be provided that the guide profile 34 on the plunger 16 forms a projection 37, so that during an intended actuation movement of the plunger 16, the control cam 36 slides up to a vertex 39 of the projection 37 against an increasing force of the return spring 45 of the damping element 19, which requires an increasing force when actuating the plunger 16. This force is no longer required after passing the vertex 39 of the projection 37, so that passing the vertex 39 of the projection 37 simultaneously causes a tactilely perceptible pressure point effect and a sudden change in the direction of the rotational movement of the damping arm 20, and thus a comparatively strong change in inductance and / or a change in a physical quantity of the coil 30. For example, the plunger 16 can be designed accordingly, as shown in Fig. The 4th variant is implemented. Using this variant of the plunger 16, the corresponding movement sequence is exemplified with the plunger 16 being increasingly pressed into the housing 12 in the intended direction of movement, i.e., from the rest position of the plunger 16 towards the actuation position, in Fig. 14, Fig. 15 and Fig. 16 shown, from the resting position in Fig. 14 via an intermediate position in Fig. 15 to the actuation position in Fig. 16.

[0065] Fig. 17 and Fig. 18 show the in Fig. Figure 4 on the right shows a variant of the plunger 16 in different representations. The plunger 16 has a main body 22, which executes the movement of the plunger 16, and a moving body 23. In Fig. 17 these two components of the pestle are assembled and in Fig. The main body 22 is shown disassembled in Figure 18. It has a bottom surface 24 facing the circuit substrate 18 and a top surface 25 opposite the bottom surface 24, with a recess 26 laterally between the bottom surface 24 and the top surface 25. The moving element 23 is inserted into this recess 26 and is rotatably mounted on a base 28 of the recess 26 opposite an opening 27 of the recess 26 about an axis of rotation 29 perpendicular to the intended direction of movement 46 of the main body 22.

[0066] The recess 26 defines a movement space 31 for the moving body 23 with an upper stop 32 on the side of the top 25 of the main body 22 and a lower stop 33 on the side of the bottom 24 of the main body 22, in which the moving body 23 is rotatable between the upper stop 32 and the lower stop 33.

[0067] The moving body 23 forms the guide profile 34 of the plunger 16. The guide profile 34 forms a projection 37, which is comparable to the projection described above in the Fig. 4 central variant of the plunger 16. Furthermore, the guide profile 34 forms a recess 38 on the side of the projection 37 facing the underside 24 of the main body 22.

[0068] The moving body 23 has a top surface 40 and a bottom surface 41. In the illustrated embodiment, stop lugs 42 are attached and / or formed on the bottom surface 41. These could alternatively or additionally also be attached and / or formed on the top surface 40.

[0069] Using this variant of the plunger 16 with main body 22 and moving body 23, the associated movement sequence is exemplified with the plunger 16 being increasingly pressed into the housing 12 in the intended direction of movement, i.e. from the rest position of the plunger 16 towards the actuation position, in Fig. 19 to Fig. 22 shown, from the resting position in Fig. 19 via two intermediate positions in Fig. 20 and Fig. 21 up to the actuation position in Fig. 22.

[0070] In the rest position of the plunger 16, the moving body 23 rests against the lower stop 33 and the control cam 36 rests in the recess 38 against the moving body 23 (see Fig. 19) When the plunger 16 moves from its rest position towards its actuating position, the moving body 23 is initially moved towards the upper stop 32, while the control cam 36 remains in the recess 38 on the moving body 23. With further movement of the plunger 16, the moving body 23 initially rests against the upper stop 32, and the control cam 36 slides out of the recess 38 to the apex 39 of the projection 37 (see Fig. 20), against an increasing force of the return spring 45 of the damping element 19, which requires an increasing force when actuating the plunger 16. The damping arm 20 is thereby moved away from the coil 30.

[0071] Subsequently, the control cam 36 passes the apex 39 of the projection 37. At this point, the moving body 23 is abruptly moved to the lower stop 33, producing a striking noise. Simultaneously, the damping arm 20 undergoes an abrupt change in the direction of its rotation and is moved towards the coil 30 (see figure). Fig. 21). Furthermore, the aforementioned force expenditure ceases after exceeding the apex 39 of the projection 37, so that exceeding the apex 39 of the projection 37 simultaneously causes a tactilely perceptible pressure point effect and a sudden change in direction of the rotational movement of the damping leg 20 and thus a comparatively strong change in inductance and / or change in a physical quantity of the coil 30 and furthermore a striking noise from the moving body 23.

[0072] Finally, the plunger 16 is moved into the actuating position against the restoring force of the return spring 17 of the plunger 16 ( Fig. 22).

[0073] The damping element 19 can, in all design variants, consist of a ferromagnetic or paramagnetic or electrically conductive material, or at least comprise a ferromagnetic or paramagnetic or electrically conductive material in certain areas.

[0074] The damping element 19 shown in the figures is a single-piece component. Alternatively, it could also be composed of two or more components. In particular, the damping element 19 could be a stamped metal part.

[0075] The movement of the plunger described above, from which the movement of the damping element 19 originates, can be a linear movement.

[0076] In particular, the invention proposes a device for detecting a key press and / or the actuation path of a key module, in which the damping element is not, as in known key modules, placed directly on the plunger as the actuator, but is mounted separately in the housing of the key module. The movement of the damping element is coupled to the movement of the plunger by means of a variable transmission mechanism, for example, a variable gear. This makes it possible both to determine an arbitrary motion transmission coefficient and to vary the motion transmission coefficient arbitrarily during actuation.

[0077] Furthermore, in one variant, the movement of the damping element is rotary, while the plunger can perform a linear movement. A rotary bearing for the damping element offers advantages in terms of simple design, accuracy, reliability, cost, and durability.

[0078] The damping element can, for example, be designed in the form of an L-shaped lever arm. At least one, for example cylindrical, sliding cam, preferably two sliding cams, is arranged on the vertical leg, which slides on the guide profile of the plunger. The damping element is equipped with a return spring that rotates it in the direction of the coil on the circuit board. The horizontal leg of the damping element is preferably ring-shaped, i.e., as a short-circuited secondary winding, and is already partially within the magnetic field of the coil when the switch is in its rest position. This results in electromagnetic coupling between the primary coil on the circuit board and the closed secondary coil, i.e., the short-circuited secondary winding, of the damping element.The energy of the magnetic field is induced in the secondary winding of the damping element; current flows in the short-circuited secondary winding, and the induced energy is converted into heat energy. This leads to a reduction in inductance or a change in another physical characteristic.

[0079] The change can be detected and converted into a signal in various ways. During actuation, the damping element rotates into the coil's magnetic field, increasing electromagnetic coupling. This alters, for example, the inductance and consequently generates a signal. This signal change can be used to detect one or more switching points and thus to measure displacement.

[0080] The damping element can also be designed as a plate made of an electrically conductive material. In this case, the energy of the magnetic field is induced in the damping element as eddy currents and converted into heat. As in the first case, changes in inductance or other physical quantities are possible.

[0081] The rotary bearing can be implemented by means of two projections on the damping element in V-shaped bearing openings in the housing of the keypad module.

[0082] Preferably, the damping element can be manufactured cost-effectively as a stamped part, with the return spring being designed as a C-shaped bending spring. The return spring can be designed as a bending spring, a separate torsion spring, a compression spring, or a tension spring.

[0083] The plunger of the key module has at least one control lug, preferably two, with an arbitrary guide profile. For example, a continuous movement of the plunger can be converted into a continuous rotation of the damping element using an inclined contour at a constant angle. A transmission ratio or rotation angle can be set by the inclination of the slope and / or by the lever ratio on the two legs of the damping element and / or by the position of the axis of rotation. In this case, the damping element rotates proportionally to the actuation movement of the plunger. Since the magnetic field coupling increases disproportionately, a progressive nonlinear change in the inductance or output signal occurs with respect to the actuation path. This behavior proves to be suboptimal.

[0084] Furthermore, the guide profile on the plunger can be designed non-linearly. In this case, the angle between the guide profile and the control cam on the damping element can be steep in the rest position and become progressively shallower with increasing actuation, thus representing a degressive curve. As a result, the angular velocity of the damping element decreases during actuation at a constant plunger velocity, and the coil is damped degressively. In this way, the non-linearity of the inductance-displacement curve can be compensated for and linearized. Therefore, it is possible to provide sensors with degressive, progressive, and linear inductance-displacement curves.

[0085] Simultaneously, it is possible to incorporate a spring contour on the plunger, thereby creating a tactile key module. Depending on the contour of the control cam, the lateral force of the damping element's return spring generates varying resistance at the plunger. With the tactile switch, the actuation force increases until it reaches the apex of the guide profile and then decreases. The user experiences a pronounced pressure point effect when pressing the key module. Equally abruptly, the damping element moves into the coil's magnetic field, causing a sudden signal change. In any case, the pressure point and the sharp signal change are synchronized along the travel axis. The distance between the pressure point and the electrical switching point can be adjusted as desired by setting the switching threshold.

[0086] A clicker switch, i.e., one with tactile and acoustic feedback, can be implemented similarly to a pressure-point switch. However, the control contour is not located on the main body of the plunger, but rather on a moving part of the plunger, also known as the clicker. The clicker is rotatably attached to the main part of the plunger and can complete a rotational movement within a sector. When actuated, the clicker rotates around its axis until it reaches its stop against the plunger, deflecting the damping element and generating a noticeable increase in force on the plunger. After passing the apex, the clicker abruptly rotates in the opposite direction until it reaches its stop against the plunger, producing an impact sound. Simultaneously, the damping element abruptly rotates in the direction of the coil, generating a significant signal change. As with the tactile version, this signal change is synchronized with the pressure point or click point.

[0087] All switch variants are reset by means of a separate compression spring, which is located between the plunger and the switch housing.

[0088] The switch consists of at least a housing, a damping element with an integrated return spring, a plunger, and a cylindrical return spring. The housing can be one-piece, two-piece (base and cover), or multi-piece.

[0089] The above functional description refers to a variant in which the damping element is rotated towards the coil by a return spring. The guide profile on the plunger rotates the damping element away from the coil when the switch is reset and towards the coil when it is actuated. The return force is provided by an additional cylindrical compression spring, which is pre-tensioned between the housing and the plunger and acts against the force of the return spring on the damping element. When the switch is actuated, the coil is increasingly damped, so that the inductance of the sensor decreases during switch operation.

[0090] A reverse functionality is also conceivable, in which the damping of the coil decreases with increasing actuation. In this case, the inductance of the coil will increase during actuation. This can be achieved by reversing the contour of the control cam. In the plunger's rest position, the damping element is rotated towards the coil, and during actuation, the damping element rotates away from the coil.

[0091] Another design variant can be implemented by attaching or forming the guide profile on the opposite side and on the inside of the plunger.

[0092] Another possible variant involves mounting the guide profile on the vertical arm of the damping element instead of the cam, and using a simple cam on the plunger that guides the guide profile along the damping element. The guide profile can be cost-effectively embossed or, for example, injection-molded or snapped into place as a plastic part.

[0093] The return spring on the damping element can be designed as a single component, integrated with the damping element, as a bending spring. Alternatively, the return spring can be implemented as a separate bending spring, torsion spring, compression spring, or tension spring.

[0094] The plunger return spring can also be designed as a compression spring, torsion spring, extension spring or as a bending spring, for example made of wire or flat material.

[0095] The plunger of the key module preferably moves linearly and perpendicular to the keyboard housing or circuit substrate. However, it is conceivable to design the plunger movement in the key module to be rotary or contour-controlled.

[0096] The damping element is preferably mounted on a rotary bearing inside the housing. However, it is possible to mount the damping element in the housing in such a way that it can undergo linear displacement or rotation in the horizontal direction. In this case, the coil is damped by the displacement of the damping element parallel to the coil. The displacement transmission ratio and the displacement speed can be determined by the control contour on the plunger, just as in the preferred embodiment.

[0097] To improve the illumination of the keycap, a light guide can be integrated into the cover, which homogenizes the illumination or specifically illuminates certain keycap areas more intensely.

[0098] In another version, the light guide can be installed as a separate part in the switch housing.

[0099] One variant involves mounting the damping element not exclusively within the housing, as in the variant described above. In the X and Y directions, the mounting is within the housing, as in the variant described above. However, in the Z direction, the position of the damping element is determined by the circuit substrate, i.e., the printed circuit board. The bearing legs protrude through the housing and rest on the surface of the circuit substrate. This compensates for the mounting tolerances of the keypad module relative to the circuit substrate in the perpendicular direction. This has the advantage that the position of the damping element relative to the coil is always the same and does not depend on manufacturing tolerances. The damping element can, for example, be equipped with a dual-function spring section. A T-shaped spring, for instance, can ensure rotation relative to the circuit substrate and thus to the coil.The two horizontal spring tabs press the damping element vertically against the circuit substrate. Of course, other spring tab shapes are also possible, not just "T"-shaped ones. Reference symbol list 10 Device 11-key module 12 cases 13 first housing part 14 second housing part 15 Movement mechanism 16 pestles 17 Return spring of the plunger 16 18 Circuit substrate 19 Damping element 20 Damping legs of the damping element 19 21 Control arm of the damping element 19 22 Main body of the pestle 16 23 Moving body of the plunger 16 24 Underside of the main body 22 25 Top of the main body 22 26 Recess in the main body 22 27 Opening of the recess 26 28 Bottom of the recess 26 29 axis of rotation 30 coil 31 Movement space in the recess 26 32 upper stop 33 lower stop 34 Piston guide profile 16 35 Tax profile of the tax leg 21 36 Tax cam of the tax profile 35 37 Advantage of the leadership profile 34 38 Trough of the guide profile 34 39 Peak of the lead 37 40 Top of the moving body 23 41 Underside of the moving body 23 42 impact studs 43 Advantage at the damping element 19 44 Recess in the housing for projection 43 45 Return spring of the damping element 19 46 intended direction of movement of the main body 22 47 continuous recess of the damping leg 20 48 Secondary coil 49 Secondary coil winding 48 50 Lighting QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2020 127 246 A1

[0003] DE 10 2020 132 195 A1

[0003] DE 10 2020 132 198 A1

[0003] DE 10 2021 116 021 A1

[0003] DE 10 2020 132 196 A1

[0003] DE 10 2015 120 607 A1

[0003] DE 10 2015 204 440 A1

[0003] US 2010 / 0320066 A1

[0003]

Claims

[1] Device (10) for detecting a key press and / or a key travel of a key module (11) comprising a circuit substrate (18), a coil (30) arranged on or in the circuit substrate (18), a key module (11) attached to the circuit substrate (18) with a housing (12), with a movement mechanism (15) comprising a plunger (16) and a return spring (17) and with a damping element (19) for changing the inductance and / or for changing a physical quantity of the coil (30), wherein the plunger (16) is movable relative to the housing (12) between a rest position and an actuating position, wherein the damping element (19) is movable relative to the housing (12) and arranged such that a movement of the damping element (19) causes a change in inductance and / or a change in a physical quantity of the coil (30), wherein the damping element (19) is coupled to the plunger (16) such that the movement of the damping element (19) originates from a movement of the plunger (16), wherein a movement of the plunger (16) from the rest position towards the actuation position, due to the coupled movement of the damping element (19), causes a change in inductance and / or a change in a physical quantity of the coil (30), wherein the device (10) outputs at least one electrical signal to signal the key actuation and / or the actuation path of the key module (11) during the change in inductance and / or change in the physical quantity of the coil (30), characterized by , that the damping element (19) is mounted on the housing (12) and / or on the circuit substrate (18), that the mobility of the damping element (19) relative to the housing (12) is a rotational mobility or a linear mobility parallel to the circuit substrate (18), and that the damping element (19) is coupled to the plunger (16) in such a way that a rotational or linear movement of the damping element (19) causing the change in inductance and / or the change in the physical size of the coil (30) deviates from the movement of the plunger (16). [2] Device (10) according to claim 1, characterized by , that a movement of the plunger (16) from the actuating position towards the rest position due to the coupled movement of the damping element (19) causes a change in inductance and / or a change in a physical quantity of the coil (30), wherein the device (10) outputs at least one electrical signal to signal the release of the button when the inductance and / or physical size of the coil (30) changes. [3] Device (10) according to claim 1 or 2, characterized by , that the damping element (19) is rotatable about an axis of rotation which runs parallel to the circuit substrate (18). [4] Device (10) according to any of the preceding claims, characterized by , that the rotational mounting of the damping element (19) on the housing (12) of the key module (11) is effected by the fact that at least two opposing lateral projections (43) formed on the damping element (19) are inserted into recesses (44) in the housing (12). [5] Device (10) according to any one of claims 1 to 3, characterized by, that the rotational mounting of the damping element (19) is effected by at least two projections (43) formed on the damping element (19) and projecting towards the circuit substrate (18), wherein the projections (43) extend through a continuous recess (44) in the housing (12) and bear against the circuit substrate (18). [6] Device (10) according to any of the preceding claims, characterized by , that the damping element (19) has a damping leg (20) and a control leg (21) which are connected at an angle to each other at one end of the legs (20, 21), wherein the damping leg (20) is pivoted towards or away from the coil (30) during the rotational movement and is displaced parallel to the circuit substrate (18) during the linear movement, and wherein the control arm (21) is coupled to the plunger (16) to convert the movement of the plunger (16) into the rotational movement or linear movement of the damping element (19). [7] Device (10) according to claim 6, characterized by , that the coupling between plunger (16) and control arm (21) of the damping element (19) is effected by the control arm (21) bearing against the plunger (16), wherein the plunger (16) has a guide profile (34) which interacts with a control profile (35) of the control arm (21), wherein the control profile (35) of the control arm (21) slides along the guide profile (34) of the plunger (16) during the movement of the plunger (16) and thereby causes the rotational movement of the damping arm (20) towards or away from the coil (30) or the linear movement of the damping arm (20) parallel to the circuit substrate (18). [8] Device (10) according to claim 7, characterized by, that a return spring (45) is integrated and / or arranged and / or attached in or on the control arm (21) of the damping element (19), wherein the return spring (45) of the damping element (19) is pre-tensioned against the housing (12) of the key module (11) and, due to its pre-tension, ensures that the control profile (35) of the control arm (21) rests against the guide profile (34) of the plunger (16). [9] Device (10) according to claim 8, characterized by , that the control profile (35) of the control arm (21) includes a control cam (36) which protrudes towards the guide profile (34) of the tappet (16). [10] Device (10) according to claim 9, characterized by , that the motion translation from the movement of the plunger (16) into the rotational movement of the damping leg (20) is determined by the shape of the guide profile (34) of the plunger (16). [11] Device (10) according to claim 10, characterized by , that the guide profile (34) on the plunger (16) decreases at least section by section in the opposite direction to an intended actuating movement of the plunger (16), so that a constant plunger movement in the actuating direction when the control cam (36) slides along the constantly decreasing section of the guide profile (34) leads to a constant angular velocity of the rotational movement of the damping leg (20) on the coil (30), or that the guide profile (34) on the plunger (16) decreases continuously, at least section by section, in the opposite direction to an intended actuation movement of the plunger (16), so that a constant plunger movement in the actuation direction, as the control cam (36) slides along the continuously decreasing section of the guide profile (34), leads to a decreasing angular velocity of the rotational movement of the damping leg (20) on the coil (30), or that the guide profile (34) on the plunger (16) increases at least section by section at a constant rate in the opposite direction to an intended actuation movement of the plunger (16), so that a constant plunger movement in the actuation direction when the control cam (36) slides along the constantly increasing section of the guide profile (34) leads to a constant angular velocity of the rotational movement of the damping leg (20) away from the coil (30), or that the guide profile (34) on the plunger (16) increases continuously less in at least sections in the opposite direction to an intended actuation movement of the plunger (16), so that a constant plunger movement in the actuation direction when the control cam (36) slides along the continuously less increasing section of the guide profile (34) leads to a decreasing angular velocity of the rotational movement of the damping leg (20) away from the coil (30). [12] Device (10) according to claim 10 or 11, characterized by , that the guide profile (34) on the plunger (16) forms a projection (37), so that during a planned actuation movement of the plunger (16), the control cam (36) slides up to a vertex (39) of the projection (37) against an increasing force of the return spring (45) of the damping element (19), which requires an increasing force when actuating the plunger (16), which ceases after passing the vertex (39) of the projection (37), so that passing the vertex (39) of the projection (37) simultaneously causes a tactilely perceptible pressure point effect and a sudden change in direction of the rotational movement of the damping leg (20) and thus a comparatively strong change in inductance and / or change in a physical quantity of the coil (30). [13] Device (10) according to claim 12, characterized by , that The plunger (16) comprises a main body (22) that executes the movement of the plunger (16) and a moving body (23), wherein the main body (22) has a bottom surface (24) facing the circuit substrate (18) and a top surface (25) opposite the bottom surface (24) and a recess (26) laterally between the bottom surface (24) and the top surface (25), into which the moving body (23) is inserted and is rotatably mounted on a base (28) of the recess (26) opposite an opening (27) of the recess (26) about an axis of rotation (29) perpendicular to the intended direction of movement (46) of the main body (22), wherein the recess (26) provides a movement space (31) for the moving body (23) with an upper stop (32) on the side of the top surface (25) of the main body (22) and a lower stop (33) on the side of the bottom surface (24) of the main body. (22) defined in which the moving body (23) is rotatable between the upper stop (32) and the lower stop (33), wherein the moving body (23) at least partially forms the guide profile (34) of the plunger (16), wherein the guide profile (34) forms the projection (37) in the area of ​​the moving body (23) and a recess (38) on the side of the projection (37) facing the underside (24) of the main body (22), wherein in the rest position of the plunger (16) the moving body (23) rests against the lower stop (33) and the control cam (36) rests in the recess (38) on the moving body (23), wherein, when the plunger (16) moves from the rest position towards the actuating position, the moving body (23) is initially moved towards the upper stop (32) and the control cam (36) continues to rest in the recess (38) on the moving body (23), wherein, with further movement of the plunger (16), the moving body (23) initially rests against the upper stop (32) and the control cam (36) slides out of the recess (38) to the apex (39) of the projection (37) and subsequently the control cam (36) passes the apex (39) of the projection (37) and thereby abruptly moves the moving body (23) to the lower stop (33) and generates a striking noise and, at the same time, moves the damping leg (20) towards the coil (30). [14] Device (10) according to claim 7 or 8, characterized by, that the guide profile (34) of the tappet (16) includes a sliding cam which protrudes towards the control profile (35) of the control leg (21) of the damping element (19). [15] Device (10) according to claim 14, characterized by , that the motion translation from the movement of the plunger (16) into the rotational movement of the damping arm (20) is determined by the shape of the control profile (35) of the control arm (21). [16] Device (10) according to any one of claims 6 to 15, characterized by , that the damping leg (20) has a continuous recess (47) which is enclosed laterally by the material of the damping leg (20), so that the damping leg (20) represents a secondary coil (48) with a short-circuited coil winding (49) which interacts inductively with the coil (30) as the primary coil. [17] Device (10) according to claim 16, characterized by, that the secondary coil (48) is rotated into or out of the magnetic field of the coil (30) when the plunger (16) moves from the rest position towards the actuation position, thereby causing a change in inductance and / or a change in a physical quantity of the coil (30). [18] Device (10) according to any one of claims 6 to 15, characterized by , that the damping leg (20) is designed as a plate which, when the plunger (16) moves from the rest position towards the actuating position, is rotated into or out of the magnetic field of the coil (30), thereby inducing eddy currents in the plate which cause the change in inductance and / or the change in a physical quantity of the coil (30). [19] Device (10) according to any of the preceding claims, characterized by, that the damping element (19) consists of a ferromagnetic or paramagnetic or electrically conductive material or at least comprises a ferromagnetic or paramagnetic or electrically conductive material in some areas. [20] Device (10) according to any of the preceding claims, characterized by , that the damping element (19) is a stamped metal part. [21] Device (10) according to any of the preceding claims, characterized by , that the movement of the plunger (16) is a linear movement or a rotational movement or a contour-controlled movement. [22] Device (10) according to any of the preceding claims, characterized by, that the key module (11) has a light (50) or is associated with a light (50) to the key module (11), wherein the light (50) is mounted on the circuit substrate (18) in such a way that it illuminates an associated keycap with symbols and / or the housing (12) of the key module (11). [23] Device (10) according to claim 22, characterized by , that one or more light guides are integrated into the housing (12) of the keypad module (11) and / or arranged as separate components in the keypad module (11). [24] Keyboard comprising one or more devices (10) according to any of the preceding claims.

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