Capacitive sensor and control element with integrated illumination

Abstract

The invention relates to a capacitive sensor (1) with integrated illumination for control elements, comprising a support plate (10) and a sensor element (20) displaceably mounted on the support plate, wherein the sensor element (20) comprises a connecting portion (21) mounted on the support plate (10) and an operating portion (22) that is displaceable relative to the support plate (10) in a predetermined operating direction (R), wherein the operating portion (22) has an operating surface (24) for receiving a force (K) that acts in the operating direction (R) and wherein the capacitive sensor (1) furthermore comprises a measuring electrode (30) that is provided on the support plate (10) and serves to detect a displacement of the operating portion (22) and determine a force (K) that acts on the operating portion (22) and leads to the displacement, wherein the capacitive sensor (1) comprises a luminous element (40) which is provided on the support plate (10) and designed to emit light in the operating direction (R), and wherein the operating portion (22) has a cutout (25), through which the luminous element (40) extends and / or through which light can be emitted in the operating direction (R) by the luminous element (40).

Description

[0001] Capacitive sensor and control element with integrated lighting

[0002] Description:

[0003] The invention relates to a capacitive sensor or a capacitive force sensor with integrated lighting and to an operating element with such a capacitive sensor and integrated lighting.

[0004] A variety of control elements and capacitive sensors are known from the state of the art. If the operating surfaces of the control elements are to be illuminated, as is often desired in motor vehicles, for example, the current approach is usually to provide a light element separate from the sensor or adjacent to the sensor on a common carrier.

[0005] Since the lighting elements are either completely independent of the

[0006] Sensor is provided as a separate functional unit or adjacent to the sensor on a common carrier, both the installation space requirement for an assembly formed from it and the complexity of an assembly formed in this way increases.

[0007] The invention is therefore based on the object of overcoming the aforementioned disadvantages and of providing a capacitive sensor or an operating element with such a sensor, which can be illuminated with a small installation space requirement.

[0008] This problem is solved by the combination of features according to the main claim and the subordinate claim.

[0009] According to the invention, a capacitive sensor with integrated lighting for operating elements is therefore proposed, which is in particular a capacitive force sensor. According to the invention, the sensor has a carrier plate and a sensor element which is displaceably mounted on the carrier plate, as well as a measuring electrode. The sensor element has a connection section which is mounted on the carrier plate and an actuating section which is displaceable relative to the carrier plate along a predetermined actuating direction. The connection section is preferably stationary relative to the carrier plate and in particular fixed thereto, whereas the actuating section is movable or displaceable, for example, parallel and in particular orthogonal to the carrier plate. The actuating section has an actuating surface for receiving a force acting in the actuating direction and in particular by orby means of a force transmission element, which can also be referred to as the actuating force. As already mentioned, the sensor also has a measuring electrode, which is provided on the carrier plate and serves to detect a displacement of the actuating section and to determine a force acting on the actuating section that leads to the displacement. According to the invention, the capacitive sensor has a lighting element provided on the carrier plate, which is preferably arranged together with the sensor element on a common side of the carrier plate and / or fixed to it.The lighting element, which is in particular an LED and more particularly a top-emitting LED, is also designed to emit light in the actuation direction, wherein this light can be guided directly or, for example, via a light-guiding element in the actuation direction to an illuminable field explained below. In order to achieve a compact design, it is also provided that the actuation section has a recess, arranged in particular centrally or centrally in the actuation section, through which the lighting element extends and / or through which light can be emitted by the lighting element in the actuation direction, so that the lighting element can be arranged in a partial area delimited by the actuation section or generally by the sensor element on a surface of the carrier plate.

[0010] Since the lighting element cannot be arranged adjacent to the sensor, but rather integrated into the area occupied by the sensor element on the carrier plate, the required installation space is greatly reduced or optimized.

[0011] Although only one luminous element is mentioned, several luminous elements or one luminous element which is designed to emit light in different colors can also be arranged according to the invention so as to pass through the recess and / or emit light through the recess.

[0012] An advantageous variant provides that the carrier plate has a first side on which the sensor element is arranged and / or fixed, the connection section of the sensor element is mounted, and the lighting element is fixed. Additionally, the carrier plate can have a second side, which is preferably opposite the first side and on which the measuring electrode is arranged and / or fixed opposite the sensor element and the lighting element. Thus, the sensor element, the lighting means, and the measuring electrode preferably overlap in a plan view of the carrier plate, with the area required for the components being determined exclusively by the sensor element and / or the measuring electrode, but not by the lighting means.

[0013] Preferably, the connecting section and / or a mounting section of the carrier plate (explained below) defines or delimits on a surface, ie on the first side of the carrier plate, at least partially and in particular completely a partial area on or in which the lighting element is arranged and / or fixed. For this purpose, the connecting section can, for example, be annular or generally surround the partial area with a closed contour. Alternatively, however, the connecting section can also have other shapes and, for example, be formed from two or more parts, which can, in particular, be arranged evenly distributed around the partial area.

[0014] In addition to the connecting section and the actuating section, the sensor element can also have at least one spring section that enables and determines the displacement and connects the connecting section and the actuating section. The shape of the at least one spring section can, in particular, determine the displacement or the force necessary for a displacement as well as the displacement path along which the actuating section of the sensor element can be displaced by the actuating force. If a force is introduced into the sensor element via the actuating section or the actuating surface, the sensor element can be supported on the carrier plate via the connecting section and, via the at least one spring section, provide a spring force that counteracts the actuating force, thereby determining the displacement of the actuating section.The displacement of the actuating section in turn leads to a change in an electric field that can be provided by the measuring electrode, which in turn can be detected and thus evaluated at the measuring electrode, so that the displacement and the actuating force leading to the displacement can be determined from the change in the electric field.

[0015] It is preferably provided that the connecting section surrounds the actuating section at least in sections and in particular completely, in particular in a plan view of the carrier plate.

[0016] The sensor element is designed in particular as a single piece and preferably as a stamped and bent part.

[0017] The carrier plate can be a printed circuit board or a layer of a multi-layer printed circuit board. Furthermore, the carrier plate can be rigid or flexible. Furthermore, an advantageous embodiment provides that the carrier plate has a mounting section, designed in particular as a soldering surface, for fixing or surface mounting the connection section of the sensor element, i.e. for fixing the sensor element to the carrier plate. In addition, conductor tracks for electrically contacting the sensor element and / or the sensor electrode and / or the lighting element can be arranged, formed and / or integrated into the carrier plate, for example by means of printing or etching technology or using multi-layer, thin-film or thick-film technology.

[0018] The measuring electrode is preferably a coil former, which can be arranged on the carrier plate or, in the case of a multilayer circuit board, between two layers. The coil former can, for example, also be formed by conductor tracks produced using printing or etching technology, which can be integrated directly into the layer or circuit board.

[0019] In particular, the light element requires a conductor track for each connection to provide power or control. For a simple light element with two connections, two conductor tracks are required.

[0020] The conductor tracks for contacting the luminous element can extend from outside the defined partial area into it or enable an electrical connection to the luminous element arranged within the partial area. For this purpose, for example, a first conductor track can be formed integrally with the mounting section for the sensor element, so that the conductor track does not have to bypass the mounting section, resulting in a simpler structure.

[0021] The conductor tracks or a second conductor track can, for example, be formed in two parts and extend with the two parts up to the mounting section, wherein the two parts can be connected to one another for bridging the mounting section, for example via bonding, i.e. via a wire or through the carrier plate and in particular by a conductor track section which is formed within the carrier plate, on a side facing away from the carrier plate or, in the case of a multi-layer circuit board, on another layer of the circuit board.

[0022] However, all or both conductor tracks for contacting the lighting element or its connections can also extend through the carrier plate and be located on a second side of the carrier plate facing away from the first side or, in the case of a multi-layer circuit board, in a further layer of the circuit board or lead to the control electronics. According to an advantageous embodiment, the actuating section can be designed as a substantially planar body which can, for example, have a rectangular, square, round or oval outer contour, i.e. contour in plan view. The displacement of such a body is detectable by the measuring electrode or has a measurable effect on an electric field provided by the measuring electrode.

[0023] Furthermore, in an unactuated state, in which the actuating section, unlike in an actuated state, is not subjected to the actuating force, the actuating section can be spaced apart from the carrier plate and / or the connecting section in the actuation direction and can thus be displaced in accordance with the spacing during actuation from the connecting section or the carrier plate. The distance preferably determines the maximum displacement path, wherein the distance can additionally or alternatively be smaller than the overall height of the lighting element, so that the lighting element passes through the actuating section through the recess in both the actuated and unactuated states.

[0024] The actuating section or the entire sensor element can also be designed as a snap-action disc in order to provide the operator with haptic feedback when actuating, i.e. when applying force.

[0025] An advantageous variant of the capacitive sensor provides that the recess is, for example, a substantially oval, circular or square hole with a closed contour or generally has a closed contour. Additionally or alternatively, the shape of the recess can correspond to an outer contour of the lighting element, i.e., it can have a contour that corresponds to the outer contour of the lighting element or is slightly larger than it, so that an area provided by the actuating section is only minimally reduced by the recess, whereby the influence of the recess on the electric field is only minimally changed. For example, the size of the recess is selected such that during a proper movement or displacement of the actuating section, there is no contact between the lighting element and the actuating section.The actuating surface to which the actuating force can be applied preferably borders directly on the recess.

[0026] In order to provide a compact assembly and simplified control, the capacitive sensor according to a further advantageous variant has control electronics which are arranged on the carrier plate and / or are in signal contact with the measuring electrode and are designed to determine a force acting on the actuating section and leading to the displacement from the displacement of the actuating section detected by the measuring electrode. In addition, the control electronics can additionally or alternatively be designed to control the lighting element depending on an external control signal and / or depending on the displacement of the actuating section and / or the force acting on the actuating section. To determine the displacement and / or the force, properties of the sensor element can be stored in the control electronics or the properties of the sensor element can be retrieved from the control electronics.

[0027] With regard to the control of the lighting element, the control electronics can, for example, be designed to cause the lighting element to emit light for a predetermined time when a certain force or a certain displacement is applied, so that the mandatory requirement for external control is eliminated.

[0028] Additionally or alternatively, however, the external control signal can be used to control the light element, which can be transmitted to the control electronics, for example, via a dedicated control contact or via a bus line. Such a control contact for controlling the light element can, for example, be integrated into a common sensor connection together with other contacts for supplying power to the sensor and / or for transmitting the displacement and / or force detected or determined by the control electronics.

[0029] A further aspect of the invention relates to an operating element with a capacitive sensor according to the invention. The operating element has a button for receiving a force applied by an operator, which has an illuminable field. Furthermore, the operating element has a force transmission element that rests against the actuating surface of the sensor element and is designed to transmit the force applied by the operator to the button from the button to the sensor element.

[0030] An advantageous development of the operating element provides that a light guide is arranged within the force transmission element, covering the recess of the actuating section and designed to guide light emitted by the luminous element to the illuminable field. Alternatively, the force transmission element can be integrally formed as a light guide covering the recess of the actuating section and designed to guide light emitted by the luminous element to the illuminable field.

[0031] In addition, the illuminable field and / or the entire key in particular can be designed as a diffuser and / or a diffuser can be arranged between the lighting element and the key, so that the light is scattered by the diffuser.

[0032] The illuminable field or diffuser can also have the form of a symbol or pictogram or be designed as such. The features disclosed above can be combined in any way, as long as this is technically possible and they do not contradict each other.

[0033] Other advantageous developments of the invention are characterized in the subclaims or are presented in more detail below, together with the description of the preferred embodiment of the invention, with reference to the figures. They show:

[0034] Fig. 1 shows a capacitive sensor in partial section;

[0035] Fig. 2 shows a sensor element of a capacitive sensor;

[0036] Fig. 3 is a plan view of a carrier plate of a capacitive sensor;

[0037] Fig. 4 shows an operating element in an unactuated state in a side sectional view;

[0038] Fig. 5 the control element in an actuated state in a side sectional view.

[0039] The figures are schematic examples. Identical reference numerals in the figures indicate identical functional and / or structural features.

[0040] Figure 1 shows a partial section of a capacitive sensor 1, in which a sensor element 20 is fixed to a first side 11 of a carrier plate 10 on a mounting section 14 designed as a soldering surface and a measuring electrode 30 is arranged on an opposite second side 12 of the carrier plate 10, which measuring electrode is designed to provide an electric field and to detect a change in the electric field through the sensor element 20.

[0041] The sensor element 20 has a connecting section 21, which is fixed to the mounting section 14, an actuating section 22, and a plurality of spring sections 23 connecting the connecting section 21 to the actuating section 22, which spring sections enable mobility or displacement of the actuating section 22 relative to the connecting section 21. Furthermore, the spring sections 23 provide a spring force which acts as a counterforce to a force K acting on the actuating surface 24 in the actuation direction R, so that the spring sections 23, preferably together with the actuating section 22, determine which force K is necessary for a specific displacement of the actuating section 22 along the actuation direction R.

[0042] In the present case, the carrier plate 10 also forms a layer 10 of a multilayer printed circuit board, which has a further layer 82, so that the measuring electrode 30 is sandwiched and protected between the layers 10, 82.

[0043] According to the proposed design, it is provided that the connecting section 21 of the sensor element 20 or the mounting section 14 on the first side 11 or the surface 11 of the carrier plate 10 delimits a partial area 13 and from the surrounding surface 11, wherein the actuating section 22 is held movably adjacent to this partial area 13 and a lighting element 40 is fixed to the carrier plate 10 in the partial area 13 such that the lighting element 40 can emit light in or along the actuation direction R. The actuating section 22 forms a recess 25 within which the lighting element 40 is arranged, seen in a plan view, such that the light emitted by the lighting element 40 can be emitted through the recess 25.

[0044] If an area, for example a button 60, is to be illuminated, the illuminant no longer has to be arranged adjacent to, ie on, the surface 11 of the carrier plate 10 but outside the partial area 13, but can be integrated directly and with a corresponding reduction in installation space into the capacitive sensor 1 or fixed to the area delimited by the sensor element 20 on the carrier plate 10.

[0045] In Figure 2, the sensor element 20, as used for example in the capacitive sensor 1 according to Figure 1, is shown in a plan view, ie in a view along the actuation direction R. The present sensor element differs from similar or known sensor elements in particular in that, as shown, a recess 25 is provided in the actuation section 22, which in the present case has a circular, closed contour, so that the lighting element 40 can be arranged within this contour or recess 25 and light can pass through the actuation section 22.

[0046] An actuating surface 24 for absorbing the force K acting in the actuating direction R extends radially inward to directly adjacent to the recess 25, so that the force K can continue to be transmitted over the largest possible area to the sensor element 20 and to cause a displacement of the actuating section 22.

[0047] Figure 3 shows a carrier plate 10 in a plan view, wherein the structure shown there or the features according to Figure 3 could also be used for a capacitive sensor 1 as shown in Figure 1.

[0048] It is essential that a mounting section 14 corresponding to the connection section 21 is formed on the first side 11 or surface 11 of the carrier plate 10, which section delimits a partial surface 13 of the surface 11 from the surrounding areas. The partial surface 13 can be completely delimited, as shown, or can also have a connection to the surrounding areas in sections.

[0049] Within the partial area 13, the lighting element 40 is fixed to the carrier plate 10 and is electrically contacted by two conductor tracks 15, 16 for controlling the lighting element 40. A first conductor track 15 is formed integrally with the mounting section 14, such that the lighting element 40 is electrically contacted with control electronics 50 provided on the carrier plate 10 via the first conductor track 15 and the mounting section 14. A second conductor track 16 comprises two sections or parts, of which a first part within the partial area 13 is contacted with the lighting element 40 and a second part outside the partial area 13 is contacted with the control electronics 50. The two parts of the second conductor track 16 in turn bridge the mounting section 14 and are connected to one another, for example, in a further layer of a circuit board comprising the carrier plate 10 or by bonding via a wire.

[0050] In principle, of course, both conductor tracks 15, 16 can also be formed according to the second conductor track 16 or can be led out of the partial area 13 on the second side 12.

[0051] Figures 4 and 5 show an operating element 2 with a capacitive sensor 1 according to Figure 1, wherein Figure 4 shows the operating element 2 or the sensor 1 in an unactuated state in which no force K acts on the sensor element 20 of the sensor 1, and Figure 5 shows the operating element 2 or the sensor 1 in an actuated state in which a force K that can be applied by an operator acts on the sensor element 20 of the sensor 1.

[0052] The operating element 2 comprises in particular a button 60 with an illuminable field 61 and a force transmission element 70, which is arranged between the button 60 and the sensor element 20 and rests on the actuating surface 24 of the actuating section 22.

[0053] Since the button 60 in Figure 4 is not subjected to pressure or force K, the actuating section 22 has a first distance A1 from the surface 11 or the first side 11 of the carrier plate 10, so that the electric field provided by the measuring electrode 30 is in a first state or is substantially unaffected.

[0054] If a force K or pressure is then applied by an operator to the button 60, the force K is transmitted via the force transmission element 70 to the actuating surface 24 or the actuating section 22, whereby the latter is displaced along the actuating direction R towards the surface 11 or the first side 11 of the carrier plate 10, i.e. the first distance A1 decreases towards the second distance A2, and the electric field is influenced, which can be detected by the measuring electrode 30 and evaluated in particular by the control electronics 50 to determine the force K and / or the displacement. The displacement is accordingly the change from the first distance A1 to the second distance A2.

[0055] In this case, the control electronics 50 can not only evaluate the signals transmitted by the measuring electrode 30 to determine the displacement and the force K leading to the displacement. For example, the control electronics 50 can also control the lighting element 40, wherein the control of the lighting element 40 by the control electronics 50 can be based on an external control signal and / or on the displacement of the actuating section 22 or the force K acting on the actuating section 22. If, for example, the lighting element 40 is controlled to emit a light L as soon as and as long as the force K exceeds a predetermined limit value, an external control signal can be omitted, which significantly simplifies the control of the operating element 2.

[0056] * * * * *

Claims

Patent claims 1 . Capacitive sensor (1) with integrated lighting for operating elements, comprising a carrier plate (10) and a sensor element (20) displaceably mounted on the carrier plate, wherein the sensor element (20) has a connecting section (21) mounted on the carrier plate (10) and an actuating section (22) displaceable relative to the carrier plate (10) along a predetermined actuating direction (R), wherein the actuating section (22) has an actuating surface (24) for receiving a force (K) acting in the actuating direction (R), and wherein the capacitive sensor (1) further comprises a measuring electrode (30) provided on the carrier plate (10) for detecting a displacement of the actuating section (22) and for determining a force (K) acting on the actuating section (22) and leading to the displacement, characterized in that the capacitive sensor (1) has a lighting element (40) provided on the carrier plate (10),which is designed to emit light in the actuation direction (R), wherein the actuation section (22) has a recess (25) through which the luminous element (40) extends and / or through which light can be emitted by the luminous element (40) in the actuation direction (R).

2. Capacitive sensor according to claim 1, wherein the carrier plate (10) has a first side (11) on which the sensor element (20) is arranged and / or fixed and the connecting section (21) of the sensor element (20) is mounted and the Lighting element (40) is fixed and / or wherein the carrier plate has a second side (22) on which the measuring electrode (30) is arranged and / or fixed opposite the sensor element (20) and the lighting element (40).

3. Capacitive sensor according to claim 1 or 2, wherein the connecting section (21) on a surface (11) of the carrier plate (10) at least partially delimits a partial surface (13) on which the lighting element (40) is arranged and / or fixed.

4. Capacitive sensor according to one of the preceding claims, wherein the connecting section (21) is connected to the actuating section (22) via at least one spring section (23) enabling and determining the displacement and / or wherein the connecting section (21) surrounds the actuating section (22) at least in sections.

5. Capacitive sensor according to one of the preceding claims, wherein the carrier plate (10) is a printed circuit board or a layer of a multi-layer printed circuit board, and / or wherein the carrier plate (10) is rigid or flexible, and / or wherein the carrier plate (10) has a mounting section (14) for fixing the connection section (21) to the carrier plate (10), and / or wherein conductor tracks for electrically contacting the sensor element (20) of the sensor electrode (30) and / or the lighting element (40) are arranged, formed and / or integrated into the carrier plate (10).

6. Capacitive sensor according to one of the preceding claims, wherein the actuating section (22) is designed as a flat body, the displacement of which can be detected by the measuring electrode (30) and / or is spaced apart from the carrier plate (10) and / or the connecting section (21) in an unactuated state in the actuating direction (R).

7. Capacitive sensor according to one of the preceding claims, wherein the recess (25) is a hole with a closed contour and / or wherein the recess (25) corresponds in shape to an outer contour of the lighting element (40) so that an area provided by the actuating section (22) is minimally reduced by the recess (40) and / or wherein the actuating surface (24) directly adjoins the recess (25).

8. Capacitive sensor according to one of the preceding claims, comprising control electronics (50) which are arranged on the carrier plate (10) and / or are in signal-technically contact with the measuring electrode (30) and are designed to determine, from the displacement of the actuating section (22) detected by the measuring electrode (30), a force (K) acting on the actuating section (22) and leading to the displacement, and / or to control the lighting element (40) as a function of an external control signal and / or the displacement and / or force (K).

9. Control element (2) with a capacitive sensor (1) according to one of the preceding claims, with a button (60) for receiving a command from an operator applyable force (K), which has an illuminable field (61), and a force transmission element (70) which rests on the actuating surface (24) of the sensor element (20) and is designed to transmit the force (K) from the button (60) to the sensor element (20).

10. Operating element according to the preceding claim, wherein a light guide covering the recess (25) is arranged within the force transmission element (70), which light guide is designed to guide a light emitted by the lighting element (40) to the illuminable field (61), or wherein the force transmission element (70) is integrally designed as a light guide covering the recess (25), which light guide is designed to guide a light emitted by the lighting element (40) to the illuminable field (61).

11. Control element according to one of the two preceding claims, wherein the illuminable field (61) and / or the button (60) is designed as a diffuser and / or a diffuser is arranged between the lighting element (40) and the button (60).

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