SENSOR DEVICE FOR A MOTOR VEHICLE

Description

[0001] The invention relates to a sensor device for a motor vehicle comprising a sensor electrode of a capacitive sensor and a near-field transmission coil of an inductive near-field transmission device, a door handle with such a sensor device, and a motor vehicle with a door handle or such a sensor device.

[0002] Sensor devices with integrated capacitive sensors are generally known. Their use in door handles, and in particular exterior door handles of motor vehicles, is also known, for example from German patent application DE 196 17 038 A1. In this context, the capacitive sensor serves to detect the approach of a potential operator.

[0003] The capacitive sensor comprises a sensor electrode and a control and evaluation circuit. When, for example, an operator's hand approaches the sensor, the capacitance of the sensor electrode changes. This change in capacitance is detected and evaluated by the control and evaluation circuit, thus recognizing the approach.

[0004] If an approach is detected, an actuator of the vehicle can be switched, the vehicle unlocked, or a vehicle unlocking device can be activated, which, for example, depending on further authentication or identification, can unlock the vehicle.

[0005] Various keyless entry systems are suitable for further identification. Since vehicle users usually want to carry as few additional devices as possible, such as a car key, it makes sense to enable identification using devices they already carry, such as a mobile phone.

[0006] To identify and verify the user's identity, a near-field communication (NFC) device can be provided, enabling communication between the vehicle and, for example, a mobile phone at close range. Such a NFC device can be based on the international Near Field Communication (NFC) transmission standard.

[0007] A vehicle door handle with both a capacitive sensor and a near-field transmission device is described, for example, by WO 2014 / 146949 A1. There, a transmission coil of a near-field transmission device and a capacitive sensor electrode of the capacitive sensor are arranged side by side or independently of each other on a printed circuit board.

[0008] The problem is that the installation space in a door handle is limited, or a sensor device should be designed to reduce the required installation space in a space-saving manner, which, however, contradicts both the operating principle of a capacitive sensor and that of a near-field transmission device, since these can be made more sensitive the larger and correspondingly more space-intensive the respective sensor elements (sensor electrode and near-field transmission coil) are.

[0009] Accordingly, the sensor device proposed by WO 2014 / 146949 A1 is comparatively large and space-intensive, as the sensor elements are arranged next to each other.

[0010] To solve this problem, DE 10 2018 103 047 A1 proposes to arrange the sensor electrode inside the near-field transmission coil, thus requiring less space while simultaneously allowing for a larger surface area of ​​the sensor elements, since these are no longer arranged next to each other but inside one another.

[0011] However, a disadvantage of this is that placing the sensor electrode inside the near-field transmission coil, which serves as an antenna, reduces the field strength of the near-field transmission coil, since the electric field of the near-field transmission coil couples into the sensor electrode and thereby creates a mutual inductance that opposes and reduces the field strength of the near-field transmission coil.

[0012] Further sensor devices and aspects of such sensor devices are also known from EP 2 332 788 A1, WO 2018 / 177580 A1 and US 2019 / 376325 A1. Furthermore, a sensor device with a plurality of straight sensor sections is also known from DE 10 2017 100364 A1.

[0013] The invention is therefore based on the objective of overcoming the aforementioned disadvantages and providing a sensor device with a sensor electrode of a capacitive sensor and a near-field transmission coil of an inductive near-field transmission device, which is designed to save space and in which the capacitive sensor and the near-field transmission device interfere with or influence each other as little as possible.

[0014] This problem is solved by the combination of features according to claim 1.

[0015] According to the invention, a sensor device for a motor vehicle is proposed. The sensor device comprises a substrate on which a sensor electrode of at least one capacitive sensor and a near-field transmission coil with at least one turn of at least one inductive near-field transmission device are arranged in a planar or flat manner. The sensor electrode is surrounded at least partially by the near-field transmission coil. "Residually surrounded" in this context means that the near-field transmission coil extends over at least two, preferably three, and more preferably four sides of the sensor electrode on the substrate. According to the invention, the sensor electrode comprises and is formed by a plurality of straight, interconnected sensor sections.The sensor sections of the multiple sensor sections are arranged in series and directly connected to one another, so that each first sensor section transitions directly into a directly subsequent second sensor section. The first and second sensor sections form an angle between each other. Therefore, the first and second sensor sections are not parallel or aligned along a common axis and are thus inclined relative to each other.

[0016] The sensor device design proposed according to the invention allows the sensor area of ​​the capacitive sensor, formed by the sensor electrode, to be arranged in a space-saving manner on or within the near-field transmission coil of the inductive near-field transmission device, so that the sensor device can be designed to be extremely space-saving. Furthermore, the proposed design of the sensor electrode and the proposed arrangement of the sensor sections of the sensor electrode ensure that no or only very low mutual inductance is generated in the near-field transmission coil, which accordingly does not reduce the field strength of the near-field transmission coil or only reduces it slightly.

[0017] According to the invention, the proposed design of the sensor electrode and the proposed arrangement of the sensor sections of the sensor electrode ensure that the sensor sections do not run parallel to the near-field transmission coil or to significant sections (coil sections) of the near-field transmission coil, as far as possible. The significant sections are preferably longitudinal coil sections connected by at least one end-face coil section, wherein the longitudinal coil sections are longer than the end-face coil sections.

[0018] In addition to the resulting space-saving design, while simultaneously minimizing or eliminating any interference with the electric field of the near-field transmission coil due to back-induction in the sensor electrode, a further advantage of the sensor device according to the invention is that only one area of ​​the sensor device is relevant for the user, in which both the near-field transmission coil and the sensor electrode are located. This eliminates the need for the user to remember where to bring their hand and where to bring an identifier (e.g., a mobile phone) close to the sensor device. Where technically unavoidable, a conductor or conductor track from which the sensor electrode is formed, or the sensor sections, should have only very small or preferably no portions running parallel to the near-field transmission coil or the coil sections.If parallel sections are technically unavoidable, they should be as short as possible and not extend over the entire length of the near-field transmission coil. It is advantageous, for example, if such parallel sections are a maximum of 1 / 5, and preferably a maximum of 1 / 10, of the length of the near-field transmission coil or coil sections. Furthermore, to reduce induction, such parallel sections should be positioned at the maximum possible distance from the near-field transmission coil or coil sections, and thus in the center or on or along a center line of the near-field transmission coil.

[0019] Furthermore, the sensor sections of the multitude of sensor sections can be of the same or different lengths, and the angles between the sensor sections can also be the same or different.

[0020] An advantageous further development of the sensor device provides that the near-field transmission coil has at least one substantially straight coil section, wherein the sensor sections intersect the at least one coil section or an imaginary extension thereof in an imaginary extension. As already described, the near-field transmission coil can have longitudinal and end-face coil sections as coil sections, wherein the sensor sections preferably intersect the longitudinal coil sections or their imaginary extensions in their imaginary extension.

[0021] It may also be advantageous to provide that the near-field transmission coil has or is formed by interconnected coil sections that are essentially perpendicular to each other, which together define an essentially rectangular area of ​​the substrate within which the sensor electrode is preferably arranged.

[0022] To reduce installation space and save space, a further development is advantageous in which the sensor electrode is arranged completely in an area of ​​the substrate that is separated from the near-field transmission coil, which can be the aforementioned rectangular area.

[0023] Preferably, the substrate is a rigid or flexible printed circuit board.

[0024] Furthermore, it is advantageous if the sensor electrode and / or the near-field transmission coil are formed at least partially and in particular completely by conductor tracks formed on the substrate, so that the sensor electrode and / or the near-field transmission coil can be described as a conductor track structure.

[0025] According to a further advantageous embodiment, the sensor device also includes control electronics which are connected to the sensor electrode and / or the near-field transmission coil via signal transmission. The sensor electrode and / or the near-field transmission coil can be connected to the control electronics directly or, for example, via a connecting line, which can also be designed as a conductor. Preferably, the control electronics implement a control and evaluation circuit for controlling and evaluating the sensor electrode and / or the near-field transmission coil, so that the sensor electrode and the control electronics form the capacitive sensor and / or the near-field transmission coil and the control electronics form the inductive near-field transmission device.

[0026] The control electronics can be arranged on the substrate. The control electronics can be located on the same side or surface of the substrate as the sensor electrode and / or the near-field transmission coil. Alternatively, the control electronics can be located on the opposite side or surface of the substrate, in which case they can be connected to the sensor electrode and / or the near-field transmission coil via a signal path through or across the substrate.

[0027] Another aspect of the invention relates to a door handle for a motor vehicle with a sensor device according to the invention.

[0028] Furthermore, one aspect of the invention relates to a motor vehicle with a sensor device and / or a door handle according to the invention.

[0029] The features disclosed above can be combined in any way, provided that this is technically possible and they do not contradict each other.

[0030] Other advantageous embodiments of the invention are characterized in the dependent claims or are described in more detail below together with the description of the preferred embodiment of the invention with reference to the figures. The figures show: Fig. 1 a sensor device; Fig. 2 a sensor device with control electronics.

[0031] The figures are schematic examples. Identical reference symbols in the figures indicate identical functional and / or structural features.

[0032] Figure 1 Figure 1 shows a sensor device 1 comprising a substrate 2 on which a sensor electrode 3 of at least one capacitive sensor and a near-field transmission coil 4 with at least one turn of at least one inductive near-field transmission device are arranged in a planar fashion.

[0033] In this case, substrate 2 is a printed circuit board, wherein the sensor electrode 3 and the near-field transmission coil 4 are formed on the printed circuit board and are, for example, etched or printed conductor tracks.

[0034] In order to enable a space-saving design of the sensor device 1, the sensor electrode 3 or the sensor sections 5 which form the sensor electrode 3 are arranged completely within the near-field transmission coil 4 or within an area delimited by the near-field transmission coil 4.

[0035] The near-field transmission coil 4 is formed by the two opposing longitudinal coil sections 8 and two further end-face coil sections 8', wherein the end-face coil sections 8' are shorter than the longitudinal coil sections 8, so that the coil or the electric field induced by the coil is essentially determined by the longitudinal coil sections 8.

[0036] In order to simultaneously minimize the coupling of the electromagnetic field generated by the near-field transmission coil 4 into the sensor electrode 3, so that there is only a minimal back-induction and a correspondingly minimized weakening of the electromagnetic field, the sensor sections 5 are arranged obliquely to the longitudinal coil sections 8 and to the end-face coil sections 8' of the near-field transmission coil 4, or intersecting them in an imaginary extension.

[0037] Each pair of immediately consecutive sensor sections 5 of the plurality of sensor sections 5 encloses an angle between them, whereby the angles between the sensor sections 5 can be the same or different.

[0038] As can be clearly seen, all sensor sections 5 are oriented obliquely opposite all coil sections 8, 8' of the near-field transmission coil 4 which completely surrounds or encloses the sensor electrode 3.

[0039] Figure 2 shows a sensor device according to Figure 1 , wherein a control electronics 9 is arranged on the substrate 2, to which both the sensor electrode 3 and the near-field transmission coil 4 are connected.

Claims

1. A sensor device (1) for a motor vehicle, having a substrate (2), on which a sensor electrode (3) of at least one capacitive sensor and a near-field transmission coil (4) with at least one turn of at least one inductive near-field transmission device are arranged in a planar manner, wherein the sensor electrode (3) is at least partially surrounded by the near-field transmission coil (4), wherein the sensor electrode (3) is formed by a plurality of sensor sections (5) extending linearly and connected to one another, characterised in that the sensor sections (5) of the plurality of sensor sections (5) are connected in series and directly to one another, so that a respective first sensor section directly transitions into a directly subsequent second sensor section, wherein the first sensor section and the second sensor section enclose an angle between them, and wherein the sensor sections do not extend in parallel to the near-field transmission coil.

2. The sensor device according to claim 1, wherein the near-field transmission coil (4) has at least one substantially linear coil section (8, 8'), and wherein, in an imaginary extension, the sensor sections (5) intersect with the at least one coil section (8, 8') or an imaginary extension of the at least one coil section (8, 8').

3. The sensor device according to claim 2, wherein the near-field transmission coil (4) has coil sections (8, 8') connected and substantially at right angles to one another, which together delimit a substantially rectangular area of the substrate (2).

4. The sensor device according to any one of the preceding claims, wherein the sensor electrode (3) is completely arranged in an area of the substrate (2) delimited from the near-field transmission coil (4).

5. The sensor device according to any one of the preceding claims, wherein the substrate (2) is a rigid or flexible printed circuit board.

6. The sensor device according to any one of the preceding claims, wherein the sensor electrode (3) and / or the near-field transmission coil (4) is / are at least partially formed by conductive traces established on the substrate (2).

7. The sensor device according to any one of the preceding claims, wherein the sensor electrode (3) and / or the near-field transmission coil (4) are completely formed by conductive traces established on the substrate (2).

8. The sensor device according to any one of the preceding claims, further having control electronics (9), which are signally connected to the sensor electrode (3) and / or to the near-field transmission coil (4).

9. A door handle for a motor vehicle, having a sensor device (1) according to any one of the preceding claims.

10. A motor vehicle, having a sensor device (1) according to any one of the preceding claims 1 to 8 and / or a door handle according to the preceding claim.