OPERATING DEVICE, IN PARTICULAR IN A VEHICLE INTERIOR, AND METHOD FOR EVALUATING A TOUCH SIGNAL OF AN OPERATING DEVICE

Abstract

Operating device, particularly in a vehicle interior, comprising a capacitive sensor element (10) and a decorative layer (20) arranged on the sensor element (10), wherein the sensor element (10) is signal-connected to a controller (30) configured to generate a confirmation signal when the controller (30) receives a touch signal detected by the sensor element (10) that exceeds a predetermined threshold, and wherein the decorative layer has a layer thickness profile with varying layer thickness and the threshold is formed by a threshold profile consisting of position-dependent individual values, wherein the threshold profile is modeled on the layer thickness profile, and wherein the controller (30) outputs a fault signal when the sensor element (10) detects a touch signal and the touch signal falls below the position-dependent individual value of the threshold profile.

Description

Technical area

[0001] The present invention relates to an operating device, in particular in a vehicle interior, and a method for evaluating a touch signal of an operating device. State of the art

[0002] It is known in practice to use touch-sensitive surfaces for control devices in the interior of modern motor vehicles. Such touch-sensitive control devices typically feature a capacitive sensor element covered with a layer structure made of various materials. This layer structure is commonly referred to as a decorative layer.

[0003] JP 2016 - 38 720 A discloses an electronic device with a touch panel for a vehicle. A sensor element is integrated into the electronic device. The touch sensitivity is adjusted for surfaces of varying thickness to improve functionality.

[0004] EP 4 152 128 A1 shows a control unit for a touch panel positioned behind a glass cover. The goal is to improve user operation.

[0005] The sensor element is usually a planar component, as curving or otherwise shaping it three-dimensionally would be expensive. At the same time, however, three-dimensionally curved decorative layers are desired for vehicle design reasons to enhance the appearance of the vehicle interior. Furthermore, a three-dimensionally shaped decorative layer can improve the user-friendliness of the control device, as it creates a certain tactile quality and improves ergonomics. Therefore, films that follow the surface contour behind a hard plastic surface are sometimes used as sensor elements. However, this increases the costs of such sensor elements.

[0006] The measuring principle of a capacitive sensor element is to detect a conductive element, such as an operator's finger, in its surroundings. A confirmation signal confirming the detection of a touch should only be output once the finger has actually touched the decorative layer. However, with three-dimensionally shaped decorative layers, there is the problem that a threshold value must be defined; if exceeded, the controller generates a confirmation signal. Due to the three-dimensionally shaped decorative element, there is no constant distance between the surface of the decorative element and the sensor element, since a three-dimensionally shaped, especially soft, decorative layer has different layer thicknesses. The threshold value for generating the confirmation signal must, however, be selected such that touching the decorative layer with a finger at the point with the thickest layer triggers a confirmation signal.This, in turn, can lead to a confirmation signal being generated in other areas of the decorative layer, where the layer thickness is significantly thinner, even when the finger is not yet in contact with the decorative layer, but rather hovering over the control device. This can easily lead to incorrect operation.

[0007] The object of the invention is therefore to provide an operating device, particularly in a vehicle interior, that enables reliable and accurate touch detection. Furthermore, the object of the invention is to provide a method for evaluating a touch signal from an operating device. Description of the invention

[0008] The above-mentioned object is achieved by an operating device having the features of patent claim 1 and by a method having the features of patent claim 5.

[0009] The invention is based on the idea of ​​providing an operating device, particularly in a vehicle interior, with a capacitive sensor element and a, in particular soft, decorative layer arranged on the sensor element. The sensor element is signal-connected to a controller configured to generate a confirmation signal when the controller receives a touch signal detected by the sensor element that exceeds a predetermined threshold value. The decorative layer has a layer thickness profile with varying layer thickness. According to the invention, the threshold value is formed by a threshold value profile made up of position-dependent individual values, wherein the threshold value profile is modeled after the layer thickness profile.

[0010] The invention is therefore based on the idea of ​​replacing the static or constant threshold value known from the prior art with a threshold value curve whose individual threshold values ​​or individual values ​​are oriented depending on the respective position on the three-dimensionally shaped decorative layer. The threshold value curve is preferably determined such that a confirmation signal is always generated by the controller when the surface of the decorative layer has actually been touched, i.e., actual contact with the surface of the decorative layer is established. In this way, incorrect operations are avoided, which can occur in the prior art if a finger hovers over the surface of the decorative layer, whereby the uniform static threshold value of the sensor limit is already exceeded. The reliability of the operating device is thus increased.

[0011] The invention is particularly suitable for the use of soft decorative layers, where "soft" refers to materials that noticeably yield when touched with a finger. This applies in particular to foamed and / or soft-laminated plastics, which are pliable and therefore "soft," especially compared to hard plastics.

[0012] In a preferred embodiment of the invention, the threshold value curve is stored as a mathematical function and / or as a value table in a memory unit of the controller. In the case of a three-dimensionally shaped decorative layer whose surface design can be easily represented by a mathematical function, it is advisable to store the mathematical function in the controller and to generate the individual value according to this mathematical function in a position-dependent manner. The advantage of this variant is in particular that it makes calibration of the sensor element comparatively easy. Only one variable needs to be adapted for a mathematically described threshold value curve, with the mathematical function adopting this adaptation for all areas of the sensor element in a position-dependent manner.The use of a value table, on the other hand, makes it particularly easy to make position-dependent fine adjustments to the individual values.

[0013] In general, the decorative layer can comprise a first region and a second region, with the decorative layer having a greater layer thickness in the first region than in the second region. In particular, it is provided that an individual value of the threshold value curve assigned to the first region is smaller than an individual value of the threshold value curve assigned to the second region. Essentially, the height of the respective individual value of the threshold value curve can therefore correspond to the layer thickness of the decorative layer, with this being position-dependent.

[0014] In a specific embodiment of the invention, it can be provided that the decorative layer has a curvature with a curvature center and curvature edges, wherein the layer thickness of the decorative layer is greater in the curvature center than at the curvature edges. In this configuration, it is preferred if an individual value of the threshold value curve assigned to the curvature center is smaller than an individual value of the threshold value curve assigned to the curvature edges. The relatively lower individual value of the threshold value curve in the region of the curvature center ensures that contact with the decorative layer in the curvature center is reliably detected by the sensor element. The comparatively higher individual value of the threshold value curve in the region of the curvature edge, i.e., in the region of the smaller layer thickness, ensures that the controller only outputs a confirmation signal about a detected contact when the decorative layer actually experiences contact at the curvature edge.False triggering due to an element located close to the decorative layer, such as an operator's finger, is thus suppressed.

[0015] In this respect, it is provided that the controller outputs an operating error signal if the sensor element detects a touch signal and the touch signal falls below the position-dependent individual value of the threshold value curve. In general, it can be provided that the evaluation of the touch signal takes place within the controller, with the controller comparing the touch signal with the threshold value curve. As soon as the detected touch signal exceeds the position-dependent individual value of the threshold value curve, a confirmation signal is output. If a touch signal is detected, but the individual value of the threshold value curve is undershot at the position of the detected touch signal, then there is no actual contact with the decorative layer, so the controller outputs the operating error signal.The control therefore corrects the touch signals detected by the sensor element, whereby this correction takes into account the layer thickness of the decorative layer depending on the position.

[0016] A secondary aspect of the invention relates to a method for evaluating a touch signal from an operating device with a capacitive sensor element and a decorative layer arranged on the sensor element. The method according to the invention preferably comprises the following steps: - detecting an intensity value of a touch signal of the sensor element; - Detecting a position value of the touch signal of the sensor element; - comparing the intensity value of the touch signal with an individual value of a threshold value curve assigned to the detected position value and - Outputting a confirmation signal when the intensity value of the touch signal is greater than or equal to the individual value of the threshold curve assigned to the position value.

[0017] In the method according to the invention, intensity values ​​of a touch signal are assigned to corresponding position values ​​of the touch signal. These are compared with individual values ​​of a threshold value curve, whereby these individual values ​​are also position-dependent, i.e., each position on the sensor element is assigned a specific individual value of the threshold value curve. The assignment can be made using a mathematical function or a value table. In this way, position-dependent individual values ​​can be defined, so that the confirmation signal is only output when the decorative layer is actually touched. This prevents incorrect operation.

[0018] Preferably, a correction unit is provided that receives the intensity value and the position value of the touch signal from the sensor element and performs the step of comparing the intensity value of the touch signal with an individual value of the threshold value curve assigned to the detected position value. The correction unit thus records the intensity value of the touch signal and filters this signal or calibrates this signal based on the threshold value curve. The actual measurement in the sensor element is not affected by this. Rather, the idea is to correct the measured values ​​in a second processing step based on the threshold value curve and then output them as a corrected signal, for example, as a confirmation signal. This has the advantage that existing operating devices can also be retrofitted with the correction unit in order to reduce incorrect operation in the future.

[0019] In a preferred embodiment of the method according to the invention, the correction unit retrieves the individual value of the threshold value curve assigned to the position value from a threshold value data set stored in a memory unit. The threshold value data set can comprise a table with several individual values, each of which is assigned to a position value. Alternatively, the threshold value data set can also comprise a mathematical function on the basis of which a correction of the touch signal is carried out.

[0020] It is of course particularly preferred if the method is used to evaluate a touch signal of the operating device described above.

[0021] A further aspect of the invention relates to a computer-readable storage medium comprising instructions that, when executed by a computer, cause the computer to perform a previously described method. Such a storage medium can be, for example, a hard disk or a microcontroller. Short description of the drawings

[0022] The various and exemplary features described above can be combined with one another according to the invention, provided this is technically reasonable and suitable. This applies regardless of whether the respective features are disclosed as device and / or method features. Further features, advantages, and embodiments of the invention will become apparent from the following description of the figures and the exemplary embodiments illustrated in the figures. They show: Fig. 1 A cross-sectional view of an operating device according to the invention according to a preferred embodiment; Fig. 2 A flow chart of the method according to the invention according to a preferred embodiment; and Fig. 3 A diagram of a threshold value curve of an operating device according to the invention according to a preferred embodiment. Ways to implement the invention

[0023] Fig. Figure 1 shows a cross-sectional view of an operating device according to the invention with a sensor element 10 and a decorative layer 20. The decorative layer 20 covers the sensor element 10. The sensor element 10 can in particular be a capacitive sensor. The decorative layer 20 can completely cover the sensor element 10, as shown in Fig. 1. It is also possible that the sensor element 10 is only partially covered by the decorative layer 20.

[0024] The decorative layer 20 comprises an outer surface 26, which is curved in the illustrated embodiment. Overall, the decorative layer 20 is three-dimensionally shaped and has different layer thicknesses.

[0025] The decorative layer 20 specifically comprises a curvature 23. Furthermore, the decorative layer 20 has a first region 21, which in the illustrated embodiment according to Fig. 1 forms a curvature center 24 of the curvature 23. A second region 22 of the decorative layer 20 forms a curvature edge 25 of the curvature 23. The curvature center 24 or the first region 21 are characterized in particular in that the decorative layer 20 has a greater layer thickness in this first region 21 or in the curvature center 24 than in the second region 22 or at the curvature edge 25. The outer surface 26 of the decorative layer 20 therefore has a continuous curvature.

[0026] In this context, it should be noted that the decorative layer 20 is not formed from a single material, but can also be composed of a layered structure of different materials, particularly to create soft surfaces. Essentially, any material arranged on the sensor element 10 and having an outer surface 26 intended to be touched to trigger the operating unit is referred to as the decorative layer 20 within the scope of this invention.

[0027] Fig. Figure 1 also shows a hand 40 with a finger 41, which, by way of example, performs a touch on the decorative layer 20. As soon as the finger 41 comes close to the sensor element 10, a touch signal is triggered in the sensor element 10. The touch signal is transmitted to a controller 30, which further processes the touch signal.

[0028] Specifically, the controller 30 compares the detected touch signal with a threshold. As soon as the threshold is exceeded, a confirmation signal is output. If a touch signal is received that does not exceed the threshold but falls below it, an incorrect operation signal is output and / or the incorrect operation is suppressed.

[0029] In the prior art, the threshold was a static, fixed value. To ensure reliable detection of contact with the decorative layer 20, the threshold was set to detect contact in the first region 21, i.e., the region with the greatest layer thickness. In the prior art, this results in a confirmation signal being emitted in the second region 22, where the layer thickness is less, even before the finger touches the decorative layer, namely when the finger is positioned at a distance from the sensor element 10 that corresponds to the layer thickness of the first region 21. In this respect, a confirmation signal is triggered even though no contact with the decorative layer 20 has occurred.

[0030] To prevent such incorrect operation, the controller 30 does not perform the comparison with a static threshold value, but instead uses a threshold value curve that includes position-dependent individual values. The process of evaluating the touch signal according to an exemplary embodiment of the invention is shown by way of example in Fig. 2 shown.

[0031] Fig. Figure 2 shows the process of evaluating the touch signal detected by sensor element 10. Sensor element 10 detects a touch signal, which can occur either through an actual touch of the decorative layer 20 or through the approach of a finger 41 to the decorative layer 20. The touch signal is then forwarded to controller 30. Controller 30 comprises a correction unit 32 connected to a memory unit 31. A data set with the threshold value curve is stored in memory unit 31. The data set with the threshold value curve can be formed by a mathematical function of the threshold value curve and / or a data table with individual values, wherein the individual values ​​are each assigned to a position on sensor element 10. In this respect, sensor element 10 also transmits position values ​​of the detected touch to controller 30, in particular correction unit 32.

[0032] Overall, the correction unit 32 receives from the sensor element 10 an intensity value of the touch or touch signal as well as a position value of the touch signal. In addition, the correction unit 32 receives a threshold value curve from the storage unit 31. Based on the position value, the correction unit 32 determines the corresponding position-dependent individual value of the threshold value curve and compares this position-dependent individual value of the threshold value curve with the intensity value of the touch signal at a position of the sensor element. If the intensity value of the touch signal is greater than the individual value of the threshold value curve, the correction unit 32 outputs a confirmation signal, which in the embodiment according to Fig. 2 is transmitted to actuator 1. The confirmation signal thus confirms that a correct touch input was detected. However, if the intensity value of the touch signal at a specific position on the sensor element is below the individual value of the threshold curve assigned to that position, the controller outputs an incorrect operation signal. The incorrect operation signal can then be further evaluated, whereby a decision is made as to whether the incorrect operation should be reported or not. If a downstream algorithm decides that the incorrect operation should be reported, the incorrect operation signal is forwarded to another actuator 2. Otherwise, the incorrect operation signal is suppressed.

[0033] In Fig. 3 shows an example of a threshold value curve for a cambered outer surface 26 of a soft decorative layer 20. The diagram shown represents the respective position of the detected touch signal on the sensor element 10 on the x-axis. The y-axis shows the threshold value or the individual value of the threshold value curve for the respective touch signal depending on its position. Essentially, the threshold value curve according to Fig. 3 a threshold value curve which is for a curved decorative layer 20 according to Fig. 1 is suitable. It can be seen that the threshold value is lower the greater the layer thickness of the decorative layer 20. At the curvature edges 25, the individual value of the threshold value curve is higher than in the region of the curvature center 24. In other words, a confirmation signal is triggered in the region of the curvature edges 25 when the finger 41 is at a smaller distance from the sensor element 10 than in the region of the curvature center 24. The threshold value curve is preferably set such that the threshold value is only exceeded when the finger 41 touches the outer surface 26 of the decorative layer 20.

[0034] The present invention is also well suited for retrofitting existing control devices. In most cases, the control devices already contain a microcontroller, which, with appropriate programming, can be extended to Fig.2 can be expanded in the controller 30. In this respect, the retrofitting is cost-effective, since no component costs are incurred. Generally, the controller 30 is formed by one or more microcontrollers, preferably arranged sequentially to one another.

[0035] In summary, the advantages of the invention are, on the one hand, the possibility of using the threshold value curve to continuously adjust the processing of inputs on touch-sensitive surfaces based on their three-dimensional contours; on the other hand, the use of cost-effective, planar sensor elements with simultaneously improved operating functionality; and the use of a single, cost-effective integrated circuit (IC) with a microcontroller usually implemented within it, which saves additional component costs. Furthermore, the invention allows for easy control of layer thickness changes in the decorative layer and possible material transitions within the decorative layer, since the threshold value curve can simulate these. LIST OF REFERENCE SYMBOLS 10 Sensor element 20 decorative layers 21 first area 22 second area 23 Curvature 24 Vault center 25 Curved edge 26 Exterior surface 30 Control 31 storage unit 32 Correction unit 40 hands 41 fingers

Claims

[1] Operating device, in particular in a vehicle interior, with a capacitive sensor element (10) and a decorative layer (20) which is arranged on the sensor element (10), wherein the sensor element (10) is signal-connected to a controller (30) which is configured to generate a confirmation signal when the controller (30) receives a touch signal detected by the sensor element (10) which exceeds a predetermined threshold value, and wherein the decorative layer has a layer thickness profile with varying layer thickness and the threshold value is formed by a threshold value profile from position-dependent individual values, wherein the threshold value profile is modeled on the layer thickness profile and wherein the controller (30) outputs an incorrect operation signal when the sensor element (10) detects a touch signal and the touch signal falls below the position-dependent individual value of the threshold value profile. [2] Operating device according to claim 1characterized by that the threshold value curve is stored as a mathematical function and / or as a value table in a memory unit (31) of the controller (30). [3] Operating device according to claim 1 or 2 characterized by in that the decorative layer (20) comprises a first region (21) and a second region (22), wherein the decorative layer (20) has a greater layer thickness in the first region (21) than in the second region (22), and wherein an individual value of the threshold value curve assigned to the first region (21) is smaller than an individual value of the threshold value curve assigned to the second region (22). [4] Operating device according to one of the preceding claims characterized byin that the decorative layer (20) has a curvature (23) with a curvature center (24) and curvature edges (25), wherein the layer thickness of the decorative layer (20) is higher in the curvature center (24) than at the curvature edges (25), and an individual value of the threshold value curve assigned to the curvature center (24) is smaller than an individual value of the threshold value curve assigned to the curvature edges (25). [5] Method for evaluating a touch signal of an operating device with a capacitive sensor element (10) and a decorative layer (20) arranged on the sensor element (10), comprising the following steps: - detecting an intensity value of a touch signal of the sensor element (10); - detecting a position value of the touch signal of the sensor element (10); - comparing the intensity value of the touch signal with an individual value of a threshold value curve assigned to the detected position value and - Outputting a confirmation signal if the intensity value of the touch signal is greater than or equal to the individual value of the threshold value curve assigned to the position value and - Output of an operating error signal if the touch signal falls below the position-dependent individual value of the threshold value curve. [6] Method according to claim 5 characterized by that a correction unit (32) is provided which receives the intensity value and the position value of the touch signal from the sensor element (10) and carries out the step of comparing the intensity value of the touch signal with an individual value of the threshold value curve assigned to the detected position value. [7] Method according to claim 6 characterized by that the correction unit (32) retrieves the individual value of the threshold value curve assigned to the position value from a threshold value data set stored in a storage unit (31). [8] Method according to one of claims 5 to 7 characterized by that the operating device is designed according to one of claims 1 to 4. [9] A computer-readable storage medium comprising instructions which, when executed by a computer, cause the computer to carry out a method according to any one of claims 5 to 8.

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