Device for detecting a keystroke, keyboard, and method for detecting a keystroke

Abstract

Device (1) for detecting a key press comprising a circuit substrate (2), a key module (4) attached to the circuit substrate (2) with a keycap (3) and a movement mechanism (15) for moving the keycap (3) relative to the circuit substrate (2) between a rest position and an actuation position, and a device (10) for detecting the movement of the keycap (3) relative to the circuit substrate (2), wherein the movement mechanism (15) has at least one one-piece or multi-piece movement element (5) which, when the keycap (3) is moved relative to the circuit substrate (2), also moves at least partially relative to the circuit substrate (2) and comprises or consists of a conductive material, wherein the conductive material encloses a continuous recess (13) so that a current flow around the recess (13) is possible. wherein the device (10) for detecting the movement of the keycap (3) relative to the circuit substrate (2) comprises an electrical resonant circuit (11) with at least one capacitor (C1) and with at least one primary coil (L1) stationary in relation to the circuit substrate (2) with one or more coil turns and at least one secondary coil (L2) with a short-circuited turn, wherein the primary coil (L1) is arranged on or in the circuit substrate (2) on the rear side of the keypad module (4) opposite the keycap (3), wherein the at least one moving element (5) forms the at least one secondary coil (L2), wherein the conductive material surrounding the recess (13) is the respective short-circuited winding of the secondary coil (L2), wherein the primary coil (L1) and the at least one secondary coil (L2) are inductively coupled to each other and the strength of the inductive coupling between the primary coil (L1) and the at least one secondary coil (L2) and thus at least one physical quantity of the resonant circuit (11) changes when the keycap (3) and thus the at least one moving element (5) forming the at least one secondary coil (L2) is moved between rest position and actuation position, wherein the device (10) for detecting the movement of the keycap (3) relative to the circuit substrate (2) comprises a measuring device for detecting and / or processing at least one physical quantity of the electrical resonant circuit (11) that changes during the movement of the keycap (3) between rest position and actuation position and outputs at least one electrical signal that depends on the change in the physical quantity, characterized by the fact that the movement mechanism (15) is a parallel mechanism.

Description

[0001] The invention relates to a device for detecting a keystroke, a keyboard comprising one or more such devices and a method for detecting a keystroke.

[0002] Keyboards use a wide variety of key module types and designs. The design and the generation of a signal, such as the actuation of a key, are key factors influencing the quality of a key module and thus of a keyboard.

[0003] The majority of commercially available keypad modules are so-called mechanical keypad modules. The following contact system has long proven effective: When the keypad module is actuated, two metal contact surfaces touch, resulting in a short circuit and triggering a switching signal.

[0004] The disadvantage of conventional mechanical key modules is that material wear, particularly mechanical abrasion on the contact surfaces, is unavoidable. As a result, the longer the service life of the key modules, the more frequently they are triggered. Breakage of the contact surfaces has a particularly detrimental effect on the functionality of the key modules.

[0005] Another disadvantage of a mechanical key module is that only one switching point is provided for each actuation, meaning that exactly one signal is triggered at a specific point per actuation. Different applications, such as text entry on the one hand and games on the other, would be easier to use if the key module's switching point were at a different point during the actuation movement, meaning the signal would be triggered earlier or later. It would therefore be desirable to have an adjustable switching point so that a key module, and thus a keyboard, can be optimally used for different applications.

[0006] Another disadvantage of mechanical button modules is that only one signal is triggered per actuation. A variable signal, whether in individual steps or finely graduated or even continuously, is therefore not possible. However, many applications, such as games, require a so-called joystick function to be able to control objects at variable speeds, for example.

[0007] Further, regarding the prior art, reference is made to US Pat. No. 3,772,684 A. This document describes a keyboard without moving contacts. The keyboard has an oscillator for each key, with pressing the key changing the oscillator frequency.

[0008] The invention is based on the object of providing a device and a method for detecting a keystroke that enables a longer service life compared to conventional mechanical key modules while maintaining essentially the same switching quality and / or expands the detection and processing options for keystrokes, thereby at least partially overcoming the aforementioned disadvantages. Furthermore, a novel keyboard with such a device is to be provided.

[0009] This object is achieved by a device having the features of claim 1, a keyboard having the features of claim 10 and a method having the features of claim 12. Advantageous embodiments and further developments are specified in the respective dependent claims.

[0010] The inventive device for detecting a keystroke comprises a circuit substrate, a key module attached to the circuit substrate, comprising a keycap and a movement mechanism for moving the keycap relative to the circuit substrate between a rest position and an actuation position, and a device for detecting the movement of the keycap relative to the circuit substrate. In particular, the keycap can be movable linearly and / or perpendicularly to the circuit substrate.

[0011] A circuit substrate is understood to mean, for example, a printed circuit board and / or a circuit board and / or a circuit foil and / or a stamped part and / or another substrate, in particular with applied and / or integrated conductor tracks. The circuit substrate can also be constructed from two or more layers, for example, from two or more of the aforementioned layers. Furthermore, a circuit substrate also refers to any other reference device or reference component of the device relative to which the object moves.

[0012] The invention provides that the movement mechanism is a parallel mechanism, in particular a double-wing parallel mechanism and / or a scissor parallel mechanism.

[0013] A parallel mechanism is a mechanism that allows the keycap to be raised and lowered linearly, i.e., along a straight line, relative to the circuit substrate without changing its orientation. In particular, the keycap is neither twisted nor tilted during this linear movement. A plane of extension defined by the keycap shifts when the movement is executed with the parallel mechanism such that the resulting plane of extension after the movement runs parallel to the original plane of extension before the movement.

[0014] According to one embodiment of the invention, the movement mechanism is soldered to the circuit substrate. In particular, a base of the parallel mechanism, on which further components of the movement mechanism are mounted, for example by means of rotary bearings and / or rotary-sliding bearings, is soldered to the circuit substrate. In other embodiments, other attachment methods are also possible, for example, by gluing or clamping.

[0015] The movement mechanism comprises at least one single-part or multi-part movement element, which, when the keycap moves relative to the switching substrate, also moves at least partially relative to the switching substrate. The movement element comprises or consists of a conductive material, wherein the conductive material encloses a continuous recess (also called an opening) so that a current flow around the recess is possible. One, two, or three or more movement elements can be provided.

[0016] The device for detecting the movement of the keycap relative to the circuit substrate in turn comprises an electrical resonant circuit with at least one capacitor and with at least one primary coil fixed in relation to the circuit substrate with one or more coil turns and at least one secondary coil with a short-circuited turn.

[0017] The primary coil is located on or in the circuit substrate on the back of the key module, opposite the keycap. In particular, it can be a planar coil, although other coil types, such as a cylindrical coil, are also possible.

[0018] The at least one single-part or multi-part moving element forms the at least one secondary coil. There may be only one corresponding moving element, so that this then forms only one secondary coil. However, several moving elements may also be provided, each forming a secondary coil. The conductive material surrounding the recess forms the short-circuited turn of the secondary coil. The or each secondary coil is therefore a short-circuited secondary coil with one closed turn. A short-circuited secondary coil of this type is therefore understood to be any closed shape, for example a ring or a frame, made of electrically conductive material, which has a continuous recess (also: opening) enclosed by the conductive material, so that a current can flow around this recess.In this case, no coil or winding ends can be defined; rather, the short-circuited coil in this case consists of a closed winding.

[0019] According to the invention, it is further provided that the primary coil and the at least one secondary coil are inductively coupled to one another. When the keycap, and thus the at least one moving element forming the at least one secondary coil, moves between the rest position and the actuated position, the strength of the inductive coupling between the primary coil and the at least one secondary coil changes, and thus also at least one physical parameter of the resonant circuit.

[0020] According to the invention, the device for detecting the movement of the keycap relative to the circuit substrate additionally comprises a measuring device for detecting and / or processing at least one physical variable of the electrical resonant circuit that changes during the movement of the keycap between the rest position and the actuated position. Furthermore, this device outputs at least one electrical signal dependent on the change in the physical variable, i.e., the measuring device has a corresponding signal output device.

[0021] The advantages of the device according to the invention lie in particular in the contactless detection of the movement of the keycap and the resulting output of an electrical signal. The mechanical solutions described above and the associated problems are eliminated. This makes it possible to produce devices for detecting keystrokes on a keyboard, and thus also keyboards, with lower interference sensitivity and a longer service life compared to corresponding devices and keyboards with mechanical solutions. Furthermore, the contactless detection of movement and the subsequent output of the signal enables a qualitatively consistent detection or switching process; there are no changes, for example, in the switching point or switching reliability due to material wear, abrasion, or breakage.

[0022] Further advantages of the invention arise from the expanded detection and processing capabilities for the keycap's movement. The inductive coupling changes continuously during the keycap's movement. This applies accordingly to the physical quantity detected by the measuring device, allowing any switching points to be adjusted and a variable signal reflecting the keycap's movement and, if necessary, its speed, can be output, for example, in individual steps, finely graduated, or even continuously.

[0023] The inductive coupling of primary and secondary coils is particularly effected in the manner of a transformer, with the secondary coil additionally short-circuited.

[0024] The resonant circuit is preferably operated with alternating voltage, in particular alternating voltage with a predetermined and / or adjustable frequency, for example, 16 MHz, and is connected to a suitably equipped alternating voltage source. The capacitor can be a variable capacitor with adjustable capacitance. Furthermore, the resonant circuit can additionally comprise at least one resistor, in particular an adjustable resistor, particularly for tuning.

[0025] Preferably, the frequency and / or the capacitor are set or selected such that the resonant circuit is in the resonance range (also: in the resonance zone) for a given position of the keycap relative to the circuit substrate. Often, the alternating voltage supplies multiple resonant circuits of multiple devices according to the invention, which are assigned to or form the multiple keys of a keyboard, so that the frequency cannot be tuned to the individual resonant circuit. In this case, the resonant circuit is adapted with regard to its resonance range by adjusting the capacitor capacitance or selecting a capacitor with a suitable capacitance. The resonance intensity or resonance bandwidth can be adjusted by adjusting or selecting the resistor(s).

[0026] The resonant circuit is an LC resonant circuit, and as a subcase with resistance it is an LCR resonant circuit.

[0027] The physical quantity can be an electrical voltage, an electrical current, a resonant frequency, or the impedance of the primary coil. This can include, among other things, all measurable parameters of a resonant circuit or LC / LCR resonant circuit.

[0028] The inductive coupling between the primary and secondary coils can be achieved without a metal core, such as an iron core, in the primary and secondary coils. This is advantageous for relatively high-frequency operating voltages of the resonant circuit. However, it is also possible to provide a metal core in the primary and / or secondary coil, which proves particularly advantageous for relatively low-frequency operating voltages.

[0029] The device can have exactly one secondary coil. However, it is also possible for two, three, or more secondary coils to be arranged on or in the object. For example, these can differ in terms of their respective inductive coupling with the primary coil. By providing appropriate switches, it is possible to individually interrupt the short circuit of the individual coils and thus inductively couple only one or specific secondary coils with the primary coil (except for an insignificant additional coupling of the secondary coils with the switch open). This allows different movements to be detected and differentiated, for example in a complex movement mechanism in which multiple components form a secondary coil.

[0030] The mode of operation of the device according to the invention is explained below: The primary coil generates an alternating magnetic field in its surroundings, which penetrates the secondary coil. This inductively couples the primary and secondary coils via the alternating magnetic field. The alternating magnetic field emanating from the primary coil induces an electrical voltage in the secondary coil. Because the secondary coil is short-circuited, this leads to a current flow within the secondary coil. Compared to a non-short-circuited secondary coil, this current flow is comparatively strong due to the short circuit and the resulting low resistance of the secondary coil.

[0031] The current flow in the secondary coil in turn affects the primary coil and thus the resonant circuit (feedback). This feedback leads to changes in the physical quantities of the resonant circuit, for example the impedance of the primary coil, the resonant frequency, the voltage drop and / or the current flow. If, for example, the secondary coil is further away from the primary coil in a first position than in a second position, the inductive coupling is smaller in the first position than in the second position, since the magnetic field strength and the magnetic flux density decrease with increasing distance from the primary coil, and vice versa. Accordingly, in this example, the feedback to the primary coil and thus the change in the physical quantities is smaller in the first position than in the second position, and vice versa. This applies accordingly to intermediate positions between the first and second positions.For example, the physical quantities can also change continuously or steadily during a continuous or steady movement between the first and second positions. The first position could, for example, be the resting position of the keycap, and the second position the actuated position of the keycap. Similar effects occur when the position or orientation of the secondary coil changes within the magnetic field of the primary coil, for example, during a tilting and / or rotating movement.

[0032] The changes in the resonant circuit due to the changing feedback lead to an adjustment of the resonant circuit. If, for example, the resonant circuit is operated at its resonant frequency with a certain position of the secondary coil relative to the primary coil, the resonant frequency of the resonant circuit changes when the position of the secondary coil changes, and the resonance decays. This leads to changes in physical quantities such as voltage and current, which can be recorded and further processed by the measuring device. The resonant circuit thus forms a type of inductive proximity switch that signals the approach or departure of the keycap from the circuit substrate.

[0033] Based on this detection of the change in one or more physical quantities, various stepped and continuous signal processing can be implemented. The same applies in reverse: If the resonant circuit is not operated at its resonant frequency, the change in the distance or position and / or orientation between the primary and secondary coils and the associated change in the inductive coupling and the resulting adjustment of the resonant circuit can cause the frequency at which the resonant circuit is operated to approach or reach its resonant frequency, with corresponding effects on physical quantities such as voltage and current.

[0034] For example, a differential control can also be implemented: In this case, the starting position is between the first and second positions, with the resonant circuit preferably operating in the range of a resonance flank in the assumed position and is calibrated as the zero position of the detected physical quantity(s). A movement of the keycap toward the first position can then be interpreted as a negative movement of the keycap based on the detected change in the physical quantity(s) during signal output, and a movement of the keycap toward the second position can be interpreted as a positive movement of the keycap, or vice versa.

[0035] The movement element forming the secondary coil can comprise or consist of one or more stamped and / or bent parts made from a metal sheet. In particular, it can be a stamped and / or bent part with at least one frame-like and / or ring-like section surrounding the continuous recess. If necessary, further sections can be provided, in particular on an outer edge of the aforementioned section, for example, obliquely or vertically projecting sections for connection to elements of the movement mechanism. The movement element can be a single piece, but it can also be composed of two or three or more individual components, so that the conductive material of all components encloses the recess.

[0036] If the movement mechanism has additional components, it is advantageous if the components of the movement mechanism, with the exception of the component(s) of the movement element that forms the secondary coil, do not have any electrically closed ring-like or frame-like elements with an internal, continuous recess or opening made of a conductive material such as metal, unless these are intended to form a secondary coil within the meaning of the invention. These elements could also couple inductively with the primary coil and disrupt the inductive coupling between the primary and secondary coils. To avoid this, it is sufficient to electrically interrupt the ring or frame of the corresponding elements at least at one point. Then no current flow is possible in these elements and accordingly there is no, or at least no relevant, inductive coupling with the primary coil. This state corresponds to a transformer in idle operation.

[0037] Against this background, one embodiment of the invention therefore provides that all components of the movement mechanism that are movable relative to the circuit substrate, with the exception of the component(s) of the movement element that forms the secondary coil, are designed such that no conductive material surrounds a continuous recess and / or no continuous current flow can occur around a continuous recess and / or a ring or frame made of conductive material has a circumferential interruption around a continuous recess. The circumferential interruption is thus designed such that it prevents or makes impossible a current flow around the continuous recess.

[0038] A further development of the invention provides that a light source for illuminating the keycap is arranged on the circuit substrate in an area surrounded by the windings of the primary coil, which is particularly designed as a planar coil. The light source can be, for example, an LED or a light guide. Furthermore, the light source can be continuously dimmable or dimmable in steps.

[0039] The key module can be designed so that light from the back of the movement mechanism passes through the movement mechanism and the continuous recess in the movement element to the keycap. In this way, for example, the back of the keycap can be illuminated. Symbols made of translucent material that extends through the keycap from the front to the back are backlit and thus glow on the front, making them visible even in the dark. Illumination around the keycap is also possible.

[0040] A base of the key module and / or movement mechanism can be made at least partially of translucent material. Material emanating from the light source is then passed through the at least partially translucent base and, if necessary, also distributed in a targeted manner to achieve lighting effects on or around the keycap.

[0041] A further development of the invention provides that a base of the movement mechanism mounted on the circuit substrate and / or a frame element mounted on the circuit substrate is designed to protect the movement mechanism and / or a region of the circuit substrate opposite the rear side of the key module and / or one or more light sources and / or electronic components and / or mechanical components and / or connecting devices, for example, solder joints, arranged in a region of the circuit substrate opposite the rear side of the key module from environmental influences. Additional sealing means can be provided for this purpose if necessary.

[0042] The base of the movement mechanism can be used to movably mount other components of the movement mechanism, in particular by means of rotary bearings and / or rotary sliding bearings.

[0043] The aforementioned frame element can be a frame surrounding the key cap at least in its actuating position, in particular a decorative frame.

[0044] The primary coil, which is particularly designed as a planar coil, can be arranged on a top side and / or a bottom side of the circuit substrate and / or between at least two layers within a multilayer circuit substrate. The top side is preferably the side or surface of the circuit substrate to which the key module is also attached or which faces the key module. The bottom side is accordingly the side or surface facing away from the key module. The primary coil, which is particularly designed as a planar coil, can also be arranged between at least two layers within a multilayer circuit substrate.

[0045] A turn of the primary coil is understood in particular to mean a complete turn. In particular, the turn has at least largely a circular or oval shape or also an angular shape, for example a rectangular shape, for example with rounded corners. In the case of a planar coil, the possibly present multiple turns preferably lie in one plane, i.e. the coil wire lies in one plane and the turns therefore have different dimensions in this plane and are arranged one within the other in this plane. Accordingly, the planar coil, which may comprise numerous turns, can also have a circular or annular shape or an oval shape or an angular shape, for example a rectangular shape, optionally with rounded corners. Multiple turns of a planar coil can also run spirally into one another.

[0046] The planar coil can be arranged as a printed circuit on the top and / or bottom of the circuit substrate or even within the circuit substrate. Furthermore, the planar coil can be implemented as a metallized foil or as a stamped metal plate (stamped part).

[0047] According to a further development of the invention, the measuring device is configured such that when at least one change limit value of the physical quantity is reached or exceeded, the at least one electrical signal is output and / or that the signal strength of the at least one electrical signal changes depending on the change in the physical quantity.

[0048] The change threshold can be a common change threshold that works for both a first movement from the rest position to the actuated position and a second movement from the actuated position back to the rest position. However, it is also possible to specify two or more different change thresholds, for example, a first change threshold that works for the aforementioned first movement and a second change threshold that works for the aforementioned second movement.

[0049] The change limit values ​​mentioned can be fixed. However, it is also possible for the change limit(s) to be adjustable. This has the advantage that the so-called switching point, i.e. the exact position of the keycap during the respective movement during which at least one electrical signal is emitted, can be changed and thus adjusted without mechanically modifying the key module. This allows the keyboard user to individually set the desired switching point for their keyboard keys without having to purchase new key modules, as was previously the case. For example, the same keyboard can be used for gaming and office applications; only the switching point needs to be changed - if desired. A manufacturer can also provide a uniform keyboard model for different applications and preset the switching point differently for each specific use case.

[0050] The measuring device can be configured such that the signal strength of the at least one electrical signal depends on the position of the keycap relative to the circuit substrate. For example, a variable signal can be output, in individual steps, finely graduated, or even continuously. This is possible, for example, if the keycap is moved in such a way that the physical quantity or quantities of the resonant circuit change continuously during the movement, in particular continuously and / or continuously. The measuring device can then be configured such that the at least one electrical signal is output continuously or finely graduated or in individual steps as the keycap moves, preferably with a correspondingly continuous or finely graduated change in signal strength or in individual steps.

[0051] In this way, a so-called joystick function can be implemented on keys, at least one or individual or all keys of a keyboard, which opens up a wide range of new application possibilities, particularly in the gaming sector, but also in office applications and other applications, for example when scrolling through documents, tables and websites at variable speeds or when controlling objects at variable speeds.

[0052] The aforementioned options for adjusting the switching points of individual key modules and thus keys and / or implementing a joystick function also offer the advantage that keyboards can be recalibrated over time. Mechanical, electromechanical, and electronic components can wear out over time and / or their properties can change due to aging. In key modules and keyboards, this can lead to, for example, changes in the switching points and / or the assignment of movement positions of the damping element to output signals or signal strengths; certain functions may even be lost entirely due to adjustment effects. The aforementioned measuring device can provide for an assignment of the recorded physical quantity(s) to the strength of the output electrical signal or can specify one or more change limit values.This assignment can be adjusted if necessary – for example, due to the aforementioned wear and aging effects. This allows, for example, each individual key module and / or the entire keyboard to be recalibrated, meaning that the initial state is at least largely restored. This can be done, for example, each time the keyboard is switched on and / or by entering certain commands and / or using certain key combinations. This can, for example, compensate for the aging of components over their service life. In a similar way, manufacturing tolerances or tolerance-related differences in the key modules and / or keyboards can be compensated for by appropriate calibration or adjustment.

[0053] The keyboard according to the invention comprises one or more, preferably a plurality of, devices according to the invention. The advantages of this keyboard over conventional keyboards are evident from the above and following explanations of the device according to the invention.

[0054] The circuit substrate of the device is arranged, in particular, in a frame or housing of the keyboard. The key module and primary coil are arranged in or on the circuit substrate, wherein the primary coil can be arranged in several alternative embodiments, for example, on an upper side of the circuit substrate, on which the key module is also arranged or which faces the key module, or on a lower side opposite the upper side, or—in the case of a multilayer structure of the circuit substrate—within the circuit substrate. In addition to the primary coil and the capacitor already mentioned, further, in particular electrical or electronic, components can be provided in and / or on the circuit substrate.

[0055] The keyboard can have a bottom side and a top side opposite the bottom side, wherein the bottom side and / or the top side are made of metal or have a metallic layer, metallic additional layer, or metallic insert. This allows external interference to the impedance of the primary coils and / or the resonant circuits inside the keyboard, for example, from mobile phone radiation or metallic objects, particularly in the vicinity of the keyboard, to be shielded.

[0056] The method according to the invention relates to an operating method for the device according to the invention and / or the keyboard according to the invention. The method according to the invention is a method for detecting a keystroke with a device according to the invention and / or a keyboard according to the invention. The method comprises the steps: a) carrying out an actuating movement of the key cap with the movement mechanism designed as a parallel mechanism in such a way that the inductive coupling between the primary coil and the secondary coil and thus also at least one physical quantity of the resonant circuit changes; b) detecting and / or processing the at least one physical quantity of the resonant circuit changing due to the movement by means of the measuring device; c) Output of at least one electrical signal when a change limit of the physical quantity is reached or exceeded and / or the signal strength of the at least one electrical signal changes depending on the change in the physical quantity.

[0057] The advantages of the method and further method steps emerge from the above description of the device according to the invention.

[0058] In particular, a value of at least one physical quantity of the resonant circuit is measured throughout the entire actuation movement of the keycap. This can be, for example, an electrical voltage and / or an electrical current and / or a resonant frequency. This can include, among other things, all measurable parameters of a resonant circuit. However, other known electrical quantities can also be measured.

[0059] According to one variant, the electrical signal can be triggered when the measured value reaches or exceeds a change limit (also known as a threshold). This can occur at any time during the movement of the keycap or at the end points of the movement. Preferably, one or more change limit values ​​can be predefined. Further preferably, one or more change limit values ​​can be adjustable, as already explained above with reference to the device according to the invention.

[0060] According to an alternative or additional variant, it can also be provided to change the signal strength of the at least one electrical signal depending on the change in the physical quantity or quantities and thus, for example, to implement the joystick function already mentioned.

[0061] According to one embodiment, the resonant circuit is operated with an alternating voltage of a predetermined and / or adjustable frequency and is adjusted by setting or selecting the frequency and / or by setting or selecting the capacitance of the capacitor and / or by setting or selecting a resistor arranged in the resonant circuit such that the resonant circuit is in the resonance range at a predetermined position of the keycap relative to the circuit substrate.

[0062] A further development provides that the key cap and / or the secondary coil element is moved linearly and / or perpendicularly to the circuit substrate and / or to the primary coil, which is designed in particular as a planar coil, during the actuating movement.

[0063] It can also be provided that a distance of the secondary coil element from the circuit substrate and / or the primary coil changes during the actuating movement.

[0064] The invention will be explained in more detail below with regard to further features and advantages based on the description of embodiments and with reference to the accompanying schematic drawings.

[0065] Show Fig. 1 shows a first embodiment of a device according to the invention in an exploded view, Fig. 2 of the first embodiment in a rest position, Fig. 3 the first embodiment with the key cap removed, Fig. 4 the first embodiment with only one component of the movement mechanism, which forms a secondary coil, Fig. 5 the first embodiment without movement mechanism and key cap, only with base, Fig. 6 a cross-section through the first embodiment, at the top in a rest position and at the bottom in an actuating position, Fig. 7 shows a second embodiment of a device according to the invention in an exploded view, Fig. 8 the second embodiment in a rest position, Fig. 9 a cross section through the second embodiment in a rest position, Fig. 10 a third embodiment of a device according to the invention in an exploded view, Fig. 11 the third embodiment in a rest position, Fig. 12 a cross section through the third embodiment in a rest position, Fig. 13 a fourth embodiment of a device according to the invention in an exploded view, Fig. 14 the fourth embodiment in an exploded view with assembled movement mechanism, without frame element, Fig. 15 the fourth embodiment without keycap and frame element Fig. 16 the fourth embodiment without key cap and frame element and additionally without a second socket, in a Fig. 15 position rotated by about 90°, Fig. 17 the components of the base of the fourth embodiment, Fig. 18 a cross-section through the fourth embodiment, at the top in a rest position and at the bottom in an actuating position, Fig. 19 a representation to explain the functional principle underlying the invention, and Fig. 20 shows an exemplary representation of a device for detecting a movement of the key cap of an embodiment of the device according to the invention as a circuit diagram.

[0066] Corresponding parts and components are provided with the same reference numerals in all figures, even across different embodiments.

[0067] Fig. 1 to Fig. 6 show a first embodiment, Fig. 7 to Fig. 9 a second embodiment, Fig. 10 to Fig. 12 a third embodiment and Fig. 13 and Fig. 18 shows a fourth embodiment of a device 1 according to the invention for detecting a keystroke on a keyboard. The various embodiments differ particularly with regard to the movement mechanism used and any additional elements used.

[0068] In all embodiments, the device 1 is intended for use in a keyboard or, more specifically, in conjunction with a key of the keyboard. The device 1 comprises a circuit substrate 2, a key module 4 attached to the circuit substrate 2, comprising a keycap 3 and a movement mechanism 15 for moving the keycap 3 relative to the circuit substrate 2, specifically perpendicular to the circuit substrate 2, between a rest position and an actuation position, and a device 10 for detecting the movement of the keycap 3 relative to the circuit substrate 2.

[0069] In all embodiments, the device 1 further comprises a primary coil L1 designed as a planar coil with multiple turns, which is arranged in a fixed position with the circuit substrate 2 on a top side of the circuit substrate 2, specifically on a rear side of the key module 4 opposite the key cap 3. A light source 6, specifically an LED, is mounted on the circuit substrate 2 at the center of the primary coil L1.

[0070] In all exemplary embodiments, the movement mechanism 15 has at least one single-part or multi-part movement element 5, which, when the keycap 3 moves relative to the circuit substrate 2, also moves at least partially relative to the circuit substrate 2 and comprises or consists of a conductive material, for example a metal, wherein the conductive material encloses a continuous recess 13, so that a current flow around the recess 13 is possible. Thus, each movement element 5 forms a secondary coil L2, wherein the conductive material enclosing the recess 13 is a short-circuited turn of the secondary coil L2.

[0071] In all embodiments, the movement mechanism 15 is a parallel mechanism. In the first, second, and third embodiments, the movement mechanism 15 is specifically a scissor mechanism, while in the fourth embodiment, it is a double-wing mechanism. Any other movement mechanisms 15 may also be provided.

[0072] The scissor mechanism in the first, second, and third embodiments each comprises two scissor components that are mounted rotatably relative to one another in a central region and are each mounted at one end via a base 16 on the circuit substrate 2 in a rotationally or rotationally sliding manner, and at another, opposite end on the keycap 3. Both scissor components of the scissor mechanism can represent a movement element 5 in the sense of the above and following explanations. Alternatively, however, only one of these two components can be designed in this way; the other could then, for example, have a circumferential interruption that prevents the flow of current around the recess 13 (not shown). In the illustrated examples of the Fig. 1 to Fig. 12, each of the scissor components individually forms a movement element 5 in the above and following sense and thus forms a secondary coil L2 in the sense of the above and following explanations. Both scissor components each form a circular or frame-like element through which a current flow around the recess is possible, i.e., each of these movement elements 5 forms a short-circuited turn of a short-circuited coil with exactly one turn.

[0073] The first and third embodiments differ only in the manner in which the movement elements 5 are mounted on the circuit substrate 2. In the first embodiment, a base 16 is soldered to the circuit board for this purpose. The contact points provided for this purpose on the circuit substrate 2, as well as the base 16, are not enclosed around a recess, but are open on one side to prevent any disruptive circulating current from being induced in these components. This base 16 forms bearing points for both movement elements 5.In the third embodiment, the circuit substrate 2 itself forms these bearing points and thus a base 16 for the mounting of the movement elements 5 by comprising two layers, a conductive foil with the primary coil L1 as a planar coil and a punched and bent part made of metal on the back of the conductive foil, which forms the bearing points and thus the base for the mounting of the two movement elements 5 through the conductive foil.

[0074] In the first and third embodiments, the key module 4 and thus the key cap 3 are pre-tensioned and thus held in a rest position by a spring 18 between the movement mechanism 15 and the key cap 3, see Fig. 2, Fig. 6 above, Fig. 11 and Fig. 12. When the key cap is pressed, it moves against the spring force exerted by the spring 18 into the actuating position, see Fig. 6 down. When the pressure is released, keycap 3 returns to its resting position.

[0075] In the second embodiment, however, this spring 18 is missing; instead, a bell made of elastic material, for example a rubber bell 20, is provided, which pre-tensions the key module 4 and the key cap 3 analogously to the spring 18 and holds them in the rest position, see Fig. 9. When pressure is applied to the keycap 3, the rubber bell 20 is elastically compressed, and the keycap moves into the actuated position. When the pressure is released, the keycap 3 returns to its rest position. The connection of the moving elements 5 to the circuit substrate 2 in the second embodiment is analogous to the third embodiment, so reference is made to the above explanations. Alternatively, a connection analogous to the first embodiment is also possible here.

[0076] The aforementioned rubber bell 20 surrounds and protects the light source 6 arranged on the circuit substrate. In order to transmit the light to the key cap 3, the rubber bell 20 is designed to be translucent.

[0077] The double-wing mechanism in the fourth embodiment comprises two wing components that are mounted on a base, specifically two separate first bases 16a, for rotational movement or rotational sliding movement. These first bases 16a are soldered to the circuit substrate 2 via corresponding contact surfaces. The two bases 16a and the two wing components are made of conductive material, in particular metal. Together, they form a ring or frame around a continuous recess 13 through which a current can flow, and thus a movement element 5 and a secondary coil L2 as defined in the above and following explanations. The two wing components are clamped together by a spring 18 such that the keycap 3 assumes a rest position, see Fig. 18 above. When the key cap 3 is pressed, the spring 18 is tensioned and the key cap assumes an actuating position, see Fig. 18 down. When the pressure is released, keycap 3 returns to its resting position.

[0078] The movement elements 5 can thus be formed as a single piece (first, second, and third embodiments) or in multiple pieces (fourth embodiment). All parts of the movement elements 5 in all embodiments are stamped and bent parts formed from a metal sheet. The movement elements 5 enclose a recess 13 in a frame-like or ring-like manner. The metal surrounding the recess 13 forms a short-circuited turn of the secondary coil L2. The secondary coil L2 thus has exactly one turn and is short-circuited; an induced electric current can flow around the recess 13. Light from a light source 6 mounted on the circuit substrate 2, for example an LED or a light guide, can pass through the recess 13 to the keycap 3 and backlight it.

[0079] In all embodiments, primary coil L1 and secondary coil L2 are inductively coupled. This inductive coupling is also shown schematically in Fig. 19. The primary coil L1, also in Fig. 19 a planar coil with several turns on the top side of a circuit substrate 2, is part of a resonant circuit 11, which is described below with reference to Fig. 20 and is operated with an alternating voltage U1. As a result, the windings of the primary coil L1 are separated from the Fig. 19. In this magnetic field 19 is the secondary coil L2, also in Fig. 19 an actuating element 5 shown only schematically, specifically a ring-like or frame-like closed stamped part, with a continuous recess 13, i.e. the secondary coil L2 is short-circuited and has only one turn.

[0080] The magnetic field 19 is an alternating magnetic field due to the alternating voltage U1, which, due to the inductive coupling, causes a voltage and thus, due to the short circuit, a current flow in the secondary coil L2, which in turn feeds back to the primary coil L1. If the secondary coil L2 is now moved relative to the primary coil L1, which results in Fig. 19 is indicated by the double arrow in the middle, this affects the strength of the inductive coupling and changes physical quantities, such as voltage and current and resonance frequency, of the resonant circuit 11, to which the primary coil L1 belongs.

[0081] A measuring device (not shown in the figures) detects and processes at least one of the physical variables of the electrical resonant circuit 11 that change during the movement of the secondary coil L2, which is attributable to the movement of the keycap 3, and outputs at least one electrical signal dependent on the change in this physical variable. The strength of the inductive coupling between the primary coil L1 and the secondary coil L2, and thus at least one physical variable of the resonant circuit 11, thus change during the movement of the keycap 3 between the rest position and the actuation position.

[0082] The device 1 thus comprises a Fig. 1 to Fig. 19 not shown device 10 for detecting a movement of the key cap 3 relative to the circuit substrate 2. This device 10 is shown as a circuit diagram in Fig. 20. This device 10 comprises the aforementioned electrical resonant circuit 11 with a capacitor C1 and the primary coil L1, wherein a resistor (not shown) may be provided in addition. The resonant circuit 11 is operated with an alternating voltage U1. Fig. 1 only the primary coil L1 is shown.

[0083] How to continue in Fig. 20, the aforementioned device 10 further comprises a secondary coil L2, the ends of which are electrically short-circuited via a short-circuit line 12. This symbolizes the closed movement element 5 of the embodiments according to Fig. 1 to 19. A switch 14 is provided in the short-circuit line 12, with which the short-circuit line 12 can be interrupted and closed again. This is a variant that can be realized by an interruption in one winding of the moving element 5 that can be electrically bridged by a switch 14. If one lets Fig. 20 the switch 14 away, the circuit diagram shows the resonant circuit 11 with a moving element 5 without contact interruption, as shown in Fig. 1 to Fig. 19 is shown.

[0084] The inductive coupling of primary coil L1 and secondary coil L2 is in Fig.20 is symbolically represented by a double arrow between the two coils L1, L2. The alternating magnetic field generated by the alternating voltage U1 induces an alternating voltage U2 in the secondary coil. When the switch 14 is closed, this voltage U2 leads to a current flow in the secondary coil L2 due to the short circuit. This current leads to feedback to the primary coil L1 and thus to the resonant circuit 11. As already explained, this changes its physical parameters, which in turn is detected by the measuring device also explained above and leads to a corresponding signal output.

[0085] The movement mechanism 15 can be attached to the circuit substrate 2 by soldering, as shown in the first and fourth embodiments. However, other attachment methods are also possible, for example, by gluing or clamping, as shown in the second and third embodiments. Pins on the corresponding components of the movement mechanism 15, which engage in corresponding recesses in the circuit substrate 2, ensure the precise positioning of the parts to be soldered.

[0086] In the first and fourth embodiments, a base 16 is provided in the area of ​​the circuit substrate 5 in which the primary coil L1 is also arranged. When mounted, the base 16 partially surrounds the primary coil L1, which is designed as a planar coil, and the light source 6, thus protecting them from environmental influences. The movement mechanism 15 is also protected from environmental influences by the base 16.

[0087] In the fourth embodiment, a second base 16b made of translucent plastic is provided, which is mounted together with the two first bases 16a. The translucent plastic of the second base 16b covers the light source 6 and guides and distributes the light emitted by the light source 6 in the desired manner, while simultaneously protecting the components arranged below it. At the same time, it protects and / or guides and / or supports the spring 18.

[0088] Furthermore, in all exemplary embodiments, a frame element 8 is provided on the circuit substrate 2, which surrounds the primary coil L1 and the light source 6, and possibly other electronic components not shown, thus protecting the components and also the movement mechanism 15 from environmental influences. This frame element 8 is dimensioned such that it surrounds the keycap 3 during a movement from the illustrated rest state to the not-shown actuated state. The frame element 8 thus simultaneously represents a visible frame for the keycap 3.

[0089] It is understood that the movement of the moving element 5 and thus of the secondary coil L2 depends on the movement of the keycap 3, but does not have to exactly follow the movement of the keycap 3. The keycap 3, for example, performs a parallel movement, i.e., a linear movement toward or away from the circuit substrate. The moving element(s) 5, however, can also perform rotational and / or tilting movements or—in the case of multi-part moving elements 5—move within themselves by moving individual parts relative to one another. Even a change in the bearing or a change in the orientation of the moving element 5 relative to the circuit substrate 2 or the primary coil L1 already represents a relevant movement of the moving element 5. List of reference symbols 1 device 2 Circuit substrate, e.g. printed circuit board 3 keycaps 4 key module 5 Movement element 6 Light source 8 frame element 10 Device for detecting movement of the keycap 3 11 Resonant circuit 12 Short-circuit line of the secondary coil L2 13 Recess 14 switches 15 Movement mechanism 16 sockets 16a / b First / second base 18 spring 19 Magnetic field 20 rubber bells C1 capacitor L1 primary coil L2 secondary coil U1 alternating voltage U2 Induced alternating voltage of the secondary coil L2

Claims

[1] Device (1) for detecting a keystroke, comprising a circuit substrate (2), a key module (4) attached to the circuit substrate (2) with a keycap (3) and a movement mechanism (15) for moving the keycap (3) relative to the circuit substrate (2) between a rest position and an actuation position, and a device (10) for detecting the movement of the keycap (3) relative to the circuit substrate (2), wherein the movement mechanism (15) has at least one single-part or multi-part movement element (5) which, when the keycap (3) moves relative to the circuit substrate (2), also moves at least partially relative to the circuit substrate (2) and comprises or consists of a conductive material, wherein the conductive material encloses a continuous recess (13) so that a current flow around the recess (13) is possible, wherein the device (10) for detecting the movement of the keycap (3) relative to the circuit substrate (2) comprises an electrical resonant circuit (11) with at least one capacitor (C1) and with at least one primary coil (L1) fixed relative to the circuit substrate (2) with one or more coil turns and at least one secondary coil (L2) with a short-circuited turn, wherein the primary coil (L1) is arranged on a rear side of the key module (4) opposite the key cap (3) on or in the circuit substrate (2), wherein the at least one movement element (5) forms the at least one secondary coil (L2), wherein the conductive material surrounding the recess (13) is the respective short-circuited turn of the secondary coil (L2), wherein the primary coil (L1) and the at least one secondary coil (L2) are inductively coupled to one another and the strength of the inductive coupling between the primary coil (L1) and the at least one secondary coil (L2) and thus at least one physical variable of the resonant circuit (11) changes during the movement of the keycap (3) and thus of the at least one movement element (5) forming the at least one secondary coil (L2) between the rest position and the actuating position, wherein the device (10) for detecting the movement of the keycap (3) relative to the circuit substrate (2) comprises a measuring device for detecting and / or processing at least one physical variable of the electrical resonant circuit (11) which changes during the movement of the keycap (3) between the rest position and the actuated position and outputs at least one electrical signal dependent on the change in the physical variable, characterized by , that the movement mechanism (15) is a parallel mechanism. [2] Device (1) according to claim 1, characterized by that the moving element (5) forming the secondary coil (L2) comprises or consists of one or more stamped and / or bent parts made of a metal sheet. [3] Device (1) according to one of the preceding claims, characterized by that all components of the movement mechanism (15) that are movable relative to the circuit substrate (2), except for the component(s) of the movement element (5) that forms the secondary coil (L2), are designed in such a way that no conductive material encloses a continuous recess and / or no closed current flow can occur around a continuous recess and / or a ring or frame made of conductive material has a circumferential interruption around a continuous recess. [4] Device (1) according to one of the preceding claims, characterized by , that a light source (6) for illuminating the keycap (3) is arranged on the circuit substrate (2) in an area surrounded by the windings of the primary coil (L1), and / or that the key module (4) is designed such that light from the rear of the movement mechanism (15) passes through the movement mechanism (15) and the continuous recess (13) in the movement element (5) to the keycap (3), and / or that a base (16) of the key module (4) and / or movement mechanism (15) consists at least partially of translucent material. [5] Device (1) according to one of the preceding claims, characterized byin that a base (16) of the movement mechanism (15) mounted on the circuit substrate (2) and / or a frame element (8) mounted on the circuit substrate (2) is designed to protect the movement mechanism (15) and / or a region of the circuit substrate (2) opposite the rear side of the key module (4) and / or one or more light sources (6) and / or electronic components and / or mechanical components and / or connecting devices arranged in a region of the circuit substrate (2) opposite the rear side of the key module (4) from environmental influences. [6] Device (1) according to one of the preceding claims, characterized by that the primary coil (L1) is a planar coil and / or is arranged on a top side and / or a bottom side of the circuit substrate (2) and / or between at least two layers within a multi-layer circuit substrate (2). [7] Device (1) according to one of the preceding claims, characterized by that the measuring device is set up in such a way that when at least one change limit value of the physical quantity is reached or exceeded, the at least one electrical signal is output and / or that the signal strength of the at least one electrical signal changes as a function of the change in the physical quantity. [8] Device (1) according to claim 7, characterized by that the change limit(s) are adjustable. [9] Device (1) according to claim 7 or 8, characterized by that the measuring device is arranged such that the signal strength of the at least one electrical signal depends on the position of the key cap (3) relative to the circuit substrate (2). [10] Keyboard comprising one or more devices (1) according to claims 1 to 9. [11] Keyboard according to claim 10, characterized bythat the keyboard has a bottom side and a top side opposite the bottom side, wherein the bottom side and / or the top side are formed from metal or have a metallic layer or metallic additional layer or metallic insert. [12] Method for detecting a keystroke with a device (1) according to claims 1 to 9 and / or a keyboard according to claim 10 or 11, comprising the steps: a) carrying out an actuating movement of the key cap (3) with the movement mechanism (15) designed as a parallel mechanism in such a way that the inductive coupling between the primary coil (L1) and the secondary coil (L2) and thus also at least one physical variable of the resonant circuit (11) changes; b) detecting and / or processing the at least one physical variable of the resonant circuit (11) changing due to the movement by means of the measuring device; c) Output of at least one electrical signal when a change limit of the physical quantity is reached or exceeded and / or the signal strength of the at least one electrical signal changes depending on the change in the physical quantity. [13] Method according to claim 12, characterized by that the resonant circuit (11) is operated with an alternating voltage (U1) of predetermined and / or adjustable frequency and is set by setting or selecting the frequency and / or by setting or selecting the capacitance of the capacitor (C1) and / or by setting or selecting a resistor arranged in the resonant circuit (11) such that the resonant circuit (11) is in the resonance range at a predetermined position of the keycap (3) relative to the circuit substrate (2).

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