Switching device for converting a manual and / or mechanical delivery movement into a switching signal

Description

[0001] The invention relates to a switching device with several switching stages for converting a manual and / or mechanical delivery movement into at least an electrical switching signal by which an electrical device is controlled, according to the preamble of claim 1.

[0002] Such a switching device is already known from DE 10 2009 032 634 A1. Disclosed therein is a switching device for converting a manual and / or mechanical actuation movement into at least one switching signal by which an electrical device is controlled. For this purpose, this switching device comprises various mechanical and electrical components. A first switching signal is generated by touching an operating cap, and a second switching signal by moving the operating cap to a contact position in which an electrical switch is actuated.

[0003] Furthermore, DE 10 2015 115 248 discloses a switching device that converts a positioning movement into a corresponding electrical switching signal. The switching device consists of an annular housing in which an electrically non-conductive keypad with a metal core is arranged and held in a starting position by a spring mechanism. When the switching device is manually actuated, the keypad with the metal core moves towards a cover plate, behind which a sensor electrode is located that registers the approach of the metal core of the keypad.

[0004] Unfortunately, these mechanical and electrical components are fixed in place.

[0005] Such a switching device is a control device or human-machine interface, typically located on the cover plate of a touch-sensitive screen, also known as a touchscreen. The cover plate of the touch-sensitive screen is made of a transparent and electrically non-conductive material. A multitude of electrodes arranged in pairs form a capacitive area sensor that responds to the approach or touch of an object, such as a finger, hand, or the like. The resulting switching signals are electronically amplified and used to control an electrical device.

[0006] A disadvantage of this switching device is that, on the one hand, it does not generate any tactile feedback, and on the other hand, such a switching device can only generate a switching signal.

[0007] US Patent 2006 / 256090 A1 discloses a switching device for converting a manual or mechanical actuation movement into a switching signal. The switching device comprises a switching housing on which an operating cap is axially displaceable along its longitudinal axis against a contact surface of a sensor. At the lower end of the operating cap is a deformable, electrically conductive contact element that deforms with increasing force upon contact with the contact surface, the force acting on the operating cap being inferred from the size of the deformation area.

[0008] It is therefore an object of the invention to further develop a switching device of the type mentioned above in such a way that a multi-stage switching signal in the form of a capacitive rotary, sliding or rocking function can be generated and evaluated by it, and furthermore, tactile feedback should be generated during actuation, by which the user recognizes whether and which actuation is desired.

[0009] The problem is solved according to the invention by the features of the characterizing part of claim 1.

[0010] Further advantageous embodiments of the invention are set out in the dependent claims.

[0011] Because the operating cap is rotatably mounted in or on the switching housing, similar to a rotary switch, toggle switch, or rocker switch, and because the capacitive surface sensor detects changes in the electric field caused by the cap's rotation and / or pivoting, a multi-stage and differentiated switching signal is generated. Due to the capacitive coupling between the operating cap and the surface sensor, even the mere contact of an object, such as a finger or hand, with the operating cap is detected by the capacitive surface sensor, generating an electrical switching signal. To generate the second switching signal, the operating cap is pressed in a stroke and moved towards the capacitive surface sensor. This causes the actuating element, located between the operating cap and the capacitive surface sensor, to be elastically deformed.The capacitive surface sensor detects this change and contacts an electrically conductive contact plate.

[0012] An electrically conductive contact plate can be positioned between the operating cap and the capacitive surface sensor. In the unactuated state, the contact plate is electrically insulated from both the actuator and the operating cap. When the operating cap is actuated, it is short-circuited with the contact plate, thus capacitively coupling the operating cap to the capacitive surface sensor via the contact plate. The contact plate therefore acts as an end stop, defining the end position of the operating cap during actuation. Due to the insulated arrangement of the contact plate, the second switching signal is generated only during the short circuit between the operating cap and the contact plate. When the operating cap is released, it springs back to its initial position via the actuator.

[0013] Furthermore, it is particularly advantageous if the operating cap is movably mounted on the housing in the manner of a rotary switch and if the rotation of the operating cap is detected by the capacitive surface sensor. The rotation of the rotary switch can be detected, for example, by an eccentric arrangement of the actuating element between the operating cap and the capacitive surface sensor, or by means of a position sensor that is integrally molded or machined onto the operating cap and coupled to the capacitive surface sensor in such a way that the rotation of the operating cap is detected.

[0014] The operating cap can still be linearly guided in or on the housing, similar to a slider, so that, for example, control values ​​for the electrical device can be parameterized by moving the operating cap. A movement of the operating cap or the actuating element is detected by the capacitive surface sensor and can be confirmed, for example, by pressing the operating cap and generating the second electrical switching signal.

[0015] The operating cap can also be designed as a lever or rocker switch, which is pivotally mounted in or on the housing. By releasing or moving the operating cap, the position of the actuating element on the capacitive surface sensor changes and is detected by the sensor, allowing an input value or control value to be determined.

[0016] The drawing shows two embodiments of a switching device according to the invention, which are explained in more detail below. Specifically, it shows: Figure 1a shows an exemplary embodiment of a switching device in the unactuated state, by which a multi-stage switching signal for controlling an electrical device is generated, comprising a switching housing in which a receiving opening is incorporated, a cover plate made of an electrically conductive material and axially movably mounted in the receiving opening of the switching housing, and an actuating element shaped as a snap disc. Figure 1b shows the switching device according to Figur 1a in the actuated state, Figure 1c the components of the switching device according to Figur 1a in an exploded view, Figure 2a a first embodiment of the switching device according to Figur 1a, which is designed as a multi-stage rotary encoder, Figure 2, second embodiment of the switching device according to Figur 1a , which is designed as a multi-stage slider, Figure 3a a further development of the switching device according to Figur 1a with three switching stages, Figure 3b the switching device according to Figur 3a in the actuated state upon reaching the second switching stage, Figure 3c the switching device according to Figur 3a Upon reaching the third switching stage, Figure 4 shows the signal waveform of the switching device according to Figur 3a and Figure 5, an electrical device with a plurality of switching devices according to the Figures 1 to 3c .

[0017] In Figur 1aA switching device 1 for converting a manual and / or mechanical actuation movement into a multi-stage switching signal 10, 11, 12, by which an electrical device is controlled, is shown. The switching device 1 consists of a switching housing 3, into which a receiving opening 4 is incorporated and which is made of an electrically non-conductive material. The switching housing 3 is arranged on a cover plate 21, glued or otherwise fixed, and a capacitive area sensor 6 is arranged on the side of the cover plate 21 facing away from the switching housing 3. This sensor generates a spatially acting electric field and allows capacitive evaluation when externally influenced. A change in the electric field of the capacitive area sensor 6, for example by actuation with a finger, generates evaluable electrical signal changes, by which the position of the finger on the capacitive area sensor 6 can be determined.

[0018] The capacitive area sensor 6 can be formed from a plurality of electrode pairs – but from at least one electrode pair – which generate the electric field when energized. These electrode pairs can also be described as a capacitor circuit. A disturbance of the electric field of the capacitive area sensor 6 by an object 2 results in a measurable change in the electrical signal. The object 2 can be, for example, a hand, a finger, or a similar object 2 that can be part of such a capacitive system.

[0019] If the electric field is disturbed by the object 2, for example by actuation with a finger, the affected electrodes consequently cause a change in the electrical signal of the capacitive area sensor 6. This evaluable electrical signal change corresponds to one of the switching signals 10, 11, 12.

[0020] In the receiving opening 4 of the switching device 1, an operating cap 5 is movably mounted along the longitudinal axis 8 on the side facing away from the cover plate 21. The operating cap 5 is made of an electrically conductive material and is resiliently supported on a conductive actuating element 9 and electrically connected to it. The actuating element 9 can be designed as a snap disc and is preferably made of a metallic material, so that when the object 2 comes into contact with the operating cap 5, a capacitive coupling is established between the object 2 and the capacitive area sensor 6 via the operating cap 5 and the actuating element 9. For this purpose, the actuating element 9 is located partially within the electric field of the capacitive area sensor 6.

[0021] In this embodiment, the actuating element 9, designed as a snap disc, is dome-shaped and supported on a thin-walled, electrically insulating carrier 13. A contact plate 15 is arranged in the space enclosed by the carrier 13 and the actuating element 9. The carrier 13 can be made of a plastic film and be translucent, so that it can also serve as a light guide for the visual perception of the switching device 1.

[0022] The contact plate 15 is electrically insulated in the unactuated state of the switching device 1 and is therefore spaced apart from the operating cap 5 and from the actuating element 9 in the effective area of ​​the electric field of the surface sensor 6.

[0023] In the activated state, shown in Figur 1bIn the switching device 1, the operating cap 5 is displaced along the longitudinal axis 8, which defines the direction of travel. Due to the elastic properties of the actuating element 9, it is deformed in such a way that an electrical connection or coupling is created between the operating cap 5 and the contact plate 15. The contact plate 15 thus increases the electrical coupling with the capacitive surface sensor 6. This electrical coupling in the second switching stage is greater than the electrical coupling in the first switching stage, which is solely due to the actuating element 9, and thus generates different and therefore distinguishable switching signals 10, 11.The object 2 is electrically coupled, on the one hand, in the unactuated state to the capacitive surface sensor 6, the operating cap 5, and the actuating element 9, and on the other hand, in the actuated state by means of the operating cap 5, the actuating element 9, and the contact plate 15. Through the electrical coupling of the contact plate 15 with the operating cap 5, the contact plate 15 influences the electric field of the capacitive surface sensor 6, thereby generating a second switching signal 11. This second switching signal 11 is distinguishable from the first switching signal 10.

[0024] To ensure good differentiation between the two electrical switching signals 10, 11, the effective areas in the electric field of the capacitive area sensor 6 of the actuator 9 and the contact plate 15 are of different sizes. Due to the different effective areas of the actuator 9 and the contact plate 15, the electric field of the capacitive area sensor 6 is influenced to a greater or lesser extent, and multiple switching stages can be implemented.

[0025] The tactile and acoustic feedback of the switching device 1 is achieved through the mechanical properties of the actuating element 9, which is designed as a snap disc. In the first switching stage of the switching device 1, the snap disc is in a statically stable state. The switching signal 10 is generated when the operating cap 5 is touched. When the operating cap 5 is pressed or engaged, the snap disc is abruptly moved into its actuated state and generates tactile and acoustic feedback upon reaching the second switching stage. This abrupt deformation of the actuating element 9 in the direction of the capacitive surface sensor 6 creates an electrical short circuit between the actuating element 9 and the contact plate 15. After actuation and release of the operating cap 5, the actuating element 9 is returned to its initial position by the preload of the actuating element 9.

[0026] The individual components of the switching device 1 are shown in particular in the exploded view in Figur 1c to be taken.

[0027] In Figur 2a Figure 1 shows a two-stage switching device 1, designed as a rotary encoder. Such a switching device 1 can, for example, be used to specify a control value by means of a rotary movement and to confirm the control value specified by the rotary movement by pressing or actuating the operating cap 5.

[0028] The operating cap 5 is mounted on the switching housing 3 so as to be axially movable along the longitudinal axis 8 and rotatable about the longitudinal axis 8. On the side of the operating cap 5 facing the capacitive area sensor 6, a position encoder 14 is arranged parallel to and eccentrically with respect to the longitudinal axis 8. The position of the position encoder 14 relative to the capacitive area sensor 6 can be detected by the capacitive area sensor 6 due to capacitive coupling. For this purpose, the position encoder 14 is made of an electrically conductive material and is electrically coupled to the operating cap 5 by machining or forming it.

[0029] The rotational position or the setpoint of the switching device 1 is detected when the operating cap 5 comes into contact with the object 2. This corresponds to the first switching stage. In this stage, the first switching signal 10 is generated by the contact of the object 2, for example a hand or a finger, and the rotational position / angular position of the operating cap 5 is also detected.

[0030] The second switching stage of the switching device 1 is reached by the actuating movement of the operating cap 5 along the longitudinal axis 8. The snap disc or the actuating element 9 connects the operating cap 5 with the contact plate 15 located below the actuating element 9, thereby generating the second switching signal 15.

[0031] Due to the different positioning and the different strength of the influence on the electric field of the capacitive surface sensor 6, the two electrical switching signals 10, 11 are clearly distinguishable.

[0032] Out of Figur 2b A multi-stage switching device 1, designed as a slider, can be removed. The operating cap 5 is movably mounted in the switching housing 3 along its longitudinal axis 8 and along an axis perpendicular to the longitudinal axis 8. The position sensor 14 is arranged on the side of the operating cap 5 facing the capacitive area sensor 6 and is capacitively coupled to it. The position sensor 14, or switching device 1, remains neutral until an object 2 touches the operating cap 5 and the switching signal 10 is generated by the capacitive coupling between the object 2 and the capacitive area sensor 6.

[0033] In the Figuren 3a bis 3c A switching device 1 with three switching stages is shown. The three switching stages of the switching device 1 are achieved by a series connection of two actuating elements 9 designed as snap discs, which have different mechanical properties, so that they provide perceptible feedback sequentially – i.e., one after the other – when the switching device 1 is actuated, depending on the stroke of the operating cap 5.

[0034] The two actuating elements 9 are made of an electrically conductive material. The dome-shaped actuating elements 9, designed as snap discs, are arranged symmetrically to each other and are electrically connected. A contact plate 15 is arranged in each of the cavities formed by the dome shape of the actuating elements 9. In the undeformed state of the respective actuating element 9, the contact plate 15 is electrically insulated from it.

[0035] The first switching signal 10 is generated, analogous to the previously presented embodiments, upon contact of the operating cap 5 with the object 2. The capacitive coupling of the capacitive area sensor 6 with the object 2 is achieved through the operating cap 5 and the actuating elements 9. The second switching signal 11 is generated upon manual actuation of the operating cap 5 and a predetermined stroke. Due to the actuation movement, one of the actuating elements 9 is initially abruptly switched to the actuated state, and a capacitive coupling, similar to a parallel circuit, is established between the actuating element 9 and the contact plate 15, resulting in an electrically detectable change in the electric field of the capacitive area sensor 6. A third switching signal 12 is generated upon a further actuation movement of the operating cap 5, when the second actuating element 9 is also switched to the actuated state.This state corresponds to the third switching stage, shown in . Figur 3c This switching stage is produced analogously to the second switching stage by means of the second contact plate 15 arranged below the second actuating element 9. This change in the electric field of the capacitive surface sensor 6 is detected by it and a third switching signal 12 is generated.

[0036] The electrical properties of the actuating elements 9 and the contact plates 15, as well as the arrangement of the actuating elements 9 and the contact plates 15, ensure that the electric field of the capacitive surface sensor 6 is influenced differently.

[0037] A signal waveform of a three-stage switching device 1 is the Figure 4It can be seen that the switching signals 10, 11, have different signal values ​​and that the signal waveform between the switching signals 10, 11, 12 is abrupt. This sharp-edged and abrupt signal waveform is achieved because the respective contact plate 15 initially has electrically shielding properties and, upon a short circuit with the actuating element 9, abruptly changes the capacitive coupling with the capacitive surface sensor 6. This sharp-edged voltage waveform is particularly advantageous for achieving good differentiation between the switching signals 10, 11, 12.

[0038] In Figure 5An electrical device with a plurality of electrical switching devices 1 is to be removed. On the electrical device, the electrical switching devices 1 are configured as sliders, rotary encoders, and multi-stage pushbuttons. The electrical device can be formed from a plurality of capacitive area sensors 6, which are provided with one or more separate or mechanically coupled cover plates 21. On the side of the cover plate 21 facing away from the switching devices 1, a display unit 22 is arranged, which can be configured, for example, as a cathode ray tube, TFT, or LCD display.

Claims

1. Switching device (1) for converting a manual and / or mechanical movement into at least one switching signal (10), by means of which an an electrical device, comprising: - a switching housing (3) with a mounting opening (4) - an operating cap (5) made of an electrically conductive material and mounted movably on or in the receiving opening (4) of the switch housing (5) along a longitudinal axis through which the feed direction (8) is defined, - a capacitive surface sensor (6) which generates a spatially acting electric field for capacitive evaluation and which is arranged on the side of the operating cap (5) opposite the feed direction (8) and generates a switching signal (10) when the electric field changes, and - at least one actuating element (9) provided between the operating cap (5) and the capacitive surface sensor (6), which is electrically conductive and elastically deformable, whereby at least one capacitive coupling is created between the operating cap (5) and the capacitive surface sensor (6), wherein the switch housing (3) is arranged, glued, or otherwise fixed on a cover plate, and the capacitive surface sensor (6) is arranged outside the switch housing (3) on the side of the cover plate (21) facing away from the switch housing (3) and allows capacitive evaluation in the event of external influence, wherein the operating cap (5) is mounted in or on the switch housing (3) so that it can rotate, either in the manner of a rotary switch, a toggle switch, a lever, or a rocker, and that the rotation or swiveling of the operating cap (5) by the capacitive surface sensor (6), a change in the electric field can be detected, or is mounted so that it can be moved linearly in the manner of a slide switch or slide control, and that the sliding movement of the operating cap (5) can be detected by the capacitive surface sensor (6), wherein the first electrical switching signal (10) is generated by the actuating element (9) when the operating cap (5) is touched with the aid of the capacitive surface sensor (6), and that at least one second differentiable electrical switching signal (11, 12) is generated with the aid of the capacitive surface sensor (6).

2. Switching device (1) according to claim 1, characterized in that in that at least one position sensor (14) is attached to or molded onto the operating cap (5) and in that the position sensor (14) is capacitively coupled to the capacitive area sensor (6).