Input device, sensor unit and method for the reliable detection of touch inputs from a user

Abstract

An input device for detecting touch inputs from a user is described. The input device comprises a cover plate and a first sensor device, which is arranged on the side of the cover plate facing away from the user and is designed to detect touch inputs from the user in a first detection area on the side of the cover plate facing the user using a detection method based on capacitive detection. The input device also comprises a second sensor device, which is arranged on the side of the cover plate facing away from the user and is designed to detect touch inputs from the user in a second detection area on the side of the cover plate facing the user using an optical detection method.The second sensor device is designed to emit light and receive reflected light when carrying out the detection method, wherein the cover plate is at least partially transparent to the light emitted by the second sensor device or has a recess for the light emitted by the second sensor device. The first detection area and the second detection area overlap completely or partially. The input device also comprises an evaluation device designed to evaluate signals provided by the sensor devices and to generate an overall detection signal that only indicates a touch input from the user if both the signal provided by the first sensor device and the second sensor device indicate a touch input from the user.

Description

Field of the invention

[0001] The invention relates to an input device for detecting a user's touch inputs. The invention also relates to a sensor unit for detecting a user's touch inputs and a method for detecting a user's touch inputs using a sensor unit. Furthermore, the invention relates to a method for assembling an input device for detecting a user's touch inputs. Background of the invention

[0002] In a wide variety of technical areas, touch switches and touch input panels have replaced conventional switches and control elements. The use of touch elements offers a variety of advantages. Touch elements offer protection against moisture and leaking liquids, are easy to clean, and are not susceptible to corrosion. However, the use of touch elements often results in incorrect recognition of user inputs, with user inputs either being incorrectly recognized or not recognized at all. There are application areas where such recognition errors are intolerable. Examples include the authorization of financial transactions, for example at bank terminals, or the operation of medical devices. Problem underlying the invention

[0003] It is an object of the invention to provide an input device and a method for detecting touch inputs which enable improved security in the detection of touch inputs. Inventive solution

[0004] The stated object is achieved by an input device for detecting touch inputs from a user. The input device comprises a cover plate and a first sensor device, which is arranged on the side of the cover plate facing away from the user and is designed to detect touch inputs from the user in a first detection area on the side of the cover plate facing the user using a detection method based on capacitive detection. The input device also comprises a second sensor device, which is arranged on the side of the cover plate facing away from the user and is designed to detect touch inputs from the user in a second detection area on the side of the cover plate facing the user using an optical detection method.The second sensor device is designed to emit light and receive reflected light when carrying out the detection method, wherein the cover plate is at least partially transparent to the light emitted by the second sensor device or has a recess for the light emitted by the second sensor device. The first detection area and the second detection area overlap completely or partially. The input device also comprises an evaluation device designed to evaluate signals provided by the sensor devices and to generate an overall detection signal that only indicates a touch input from the user if both the signal provided by the first sensor device and the second sensor device indicate a touch input from the user.

[0005] The input device according to embodiments of the present invention is designed for reliable detection of touch inputs. A touch input is an event that is triggered when the user touches the cover plate of a touch sensor with their hand, part of their hand, at least one finger, or an object, or comes close enough to the cover plate to enter the detection range of the respective detection method. If touch inputs are made using an object, for example, a stylus, capacitive detection requires the use of an object made of conductive material. To detect touch inputs, the input device comprises a first sensor device based on a capacitive detection method and detecting touch inputs within a first detection range.In addition, a second sensor device is provided, which is based on optical detection and detects touch inputs within a second detection area that overlaps with the first detection area. The first detection area is a spatial area on the side of the cover plate facing the user, within which touch inputs from the user are detected by the first sensor device using capacitive detection. The second detection area is a spatial area on the side of the cover plate facing the user, within which touch inputs from the user are detected by the second sensor device using optical detection. Thus, two different detection methods are used, which preferably do not interfere with each other.Both detection methods used, i.e., optical and capacitive detection, can be implemented using sensor devices located on the side of the cover plate facing away from the user. For example, combining two completely different detection methods can improve the accuracy and reliability of touch input detection. If one of the detection methods triggers an error, the other detection method serves as a corrective.

[0006] The evaluation unit of the input device is designed to combine the signals provided by the two sensor devices and generate a combined detection signal. A user touch input is only recognized if both sensor devices detect a touch input.

[0007] The input device according to the embodiments of the invention is particularly suitable for applications in which high security standards prevail and in which reliable recognition of touch inputs is particularly important.

[0008] The invention also relates to a sensor unit for detecting touch inputs from a user. The sensor unit comprises a first sensor device, a second sensor device, and an evaluation device, wherein the sensor unit can be attached to a side of a cover plate facing away from the user. The first sensor device is designed to detect touch inputs from the user in a first detection area on the side of the cover plate facing the user using a detection method based on capacitive detection. The second sensor device is designed to detect touch inputs from the user in a second detection area on the side of the cover plate facing the user using an optical detection method, wherein the second sensor device is designed to emit light and receive reflected light when performing the detection method.The first detection area and the second detection area overlap completely or partially. The evaluation device is designed to evaluate signals provided by the sensor devices and generate an overall detection signal that only indicates a touch input from the user if both the signal provided by the first sensor device and the signal provided by the second sensor device indicate a touch input from the user.

[0009] The sensor unit according to the embodiments of the invention comprises the first sensor device based on capacitive detection, the second sensor device based on optical detection, and the evaluation device. The sensor unit is designed to be mounted on the side of a cover plate facing away from the user and from there to detect the user's touch inputs using two different detection methods. A touch input is only recognized if both detection methods detect the presence of a touch input.

[0010] The invention further relates to an input device for detecting touch inputs from a user. The input device comprises a cover plate and a sensor unit, as described above, mounted in a first region on the side of the cover plate facing away from the user. The cover plate is, at least in places, completely or partially transparent to the light emitted by the second sensor device, or has a recess for the light emitted by the second sensor device. In addition, the input device comprises a display unit arranged in a third region on the side of the cover plate facing away from the user, wherein the third region is different from the first region and the first region and the third region do not overlap. The cover plate is at least partially transparent in the third region.

[0011] The invention also relates to an input device for detecting touch inputs from a user. The input device comprises a cover plate and a first sensor device, which comprises an electrode structure arranged in or on a first region of the side of the cover plate facing away from the user. The first sensor device is designed to detect touch inputs from the user in a first detection region on the side of the cover plate facing the user using a detection method based on capacitive detection. The input device comprises a display unit for displaying content, the display unit being arranged on a first partial region of the first region of the cover plate.The cover plate and the electrode structure are fully or partially transparent in the first sub-region of the first region of the cover plate, wherein content displayed on the display unit can be fully or partially recognized through the cover plate and the electrode structure. In addition, the input device comprises a second sensor device which is arranged in a second sub-region of the first region of the cover plate, wherein the second sub-region does not overlap with the first sub-region. The second sensor device is designed to detect touch inputs from the user in a second detection region on the side of the cover plate facing the user by means of an optical detection method, wherein the second sensor device is designed to emit light and receive reflected light when carrying out the detection method.The cover plate and the electrode structure are, at least in places, completely or partially permeable to the light emitted by the second sensor device and / or have one or more recesses for the light emitted by the second sensor device. Furthermore, the input device comprises an evaluation device configured to evaluate signals provided by the sensor devices and generate an overall detection signal that only indicates a touch input from the user if both the signal provided by the first sensor device and the second sensor device indicate a touch input from the user. In this embodiment, the electrode structure covers both the display unit, for example a display unit, and the second sensor device. Regular touch inputs in the area of ​​the display unit can be detected using capacitive detection by means of the electrode structure.In addition, touch inputs within the second detection area can be detected in a particularly secure manner through the combination of optical and capacitive detection.

[0012] The invention further relates to a method for detecting touch inputs from a user using a sensor unit. The sensor unit is designed to detect touch inputs from the user on a side of a cover plate of the sensor unit facing the user, wherein the sensor unit is arranged on the side of the cover plate facing away from the user. The method comprises detecting touch inputs from the user in a first detection area on the side of the cover plate facing the user using a detection method based on capacitive detection. The method also comprises detecting touch inputs from the user in a second detection area on the side of the cover plate facing the user using an optical detection method.Furthermore, the method comprises generating an overall detection signal that indicates a user touch input only when both the capacitive detection method and the optical detection method detect a user touch input.

[0013] The invention further relates to a method for assembling an input device for detecting touch inputs from a user. The method comprises subsequently attaching a sensor unit as described above to the side of a cover plate facing away from the user in such a way that the first sensor device detects touch inputs from the user in a first detection area on the side of the cover plate facing the user, and the second sensor device detects touch inputs from the user in a second detection area on the side of the cover plate facing the user, wherein the first detection area and the second detection area overlap completely or partially. Preferred embodiments of the invention

[0014] Advantageous training and further developments, which can be used individually or in combination with one another, are the subject of the dependent claims and the following description.

[0015] According to a preferred embodiment, the first sensor device comprises an electrode arrangement for transmitting and receiving an electromagnetic field. When the user performs a touch input, for example, touches the cover plate with a finger, hand, or a conductive object, or comes close to the cover plate, the presence of the finger, hand, or conductive object changes the capacitance at at least one electrode of the electrode arrangement. The capacitance change or the effect of this change on the electromagnetic field at at least one electrode can be detected by the input device.

[0016] It is advantageous if the first sensor device is based on a projective-capacitive detection method. A projective-capacitive detection method allows for spatially resolved detection of touch events. This makes it possible to distinguish with greater accuracy between touch inputs intended by the user and artifacts that cannot be considered touch inputs.

[0017] Preferably, the first sensor device is configured to detect objects located in the first detection area using a flat electrode array. This allows, for example, a distinction to be made between touch inputs and artifacts or interfering objects.

[0018] The optical detection method is preferably one of the following: LIDAR, optical detection based on the principle of time-of-flight measurement, detection using a retro-reflective sensor, or forked light barrier. What all of these optical detection methods have in common is that the second detection area is scanned or examined using a light signal.

[0019] According to a preferred embodiment, the second sensor device comprises a LIDAR sensor configured to scan the second detection area using a laser. A LIDAR sensor may, for example, comprise a deflection unit that allows the second detection area to be scanned using a laser beam. This enables spatially resolved detection of the second detection area and thus a better differentiation between touch events and artifacts.

[0020] Preferably, the LIDAR sensor is configured to detect objects located in the second detection area. Further preferably, the LIDAR sensor is configured to create a distance profile of objects located in the second detection area using time-of-flight analysis. For example, the LIDAR sensor can scan the second detection area with a laser and create a depth profile using time-of-flight analysis. The 3D depth profile created by a LIDAR sensor improves the accuracy of detecting touch inputs.

[0021] According to a preferred embodiment, the second sensor device comprises an optical time-of-flight sensor configured to emit a light signal and receive reflected light, wherein the input device is configured to detect touch inputs from the user using a time-of-flight analysis of the light. The inclusion of a time-of-flight analysis improves the detection of touch inputs. A touch input is only recognized when the user's finger, hand, or object is within a specific distance range relative to the cover plate.

[0022] It is advantageous if at least one of the sensor devices is also designed as a fingerprint sensor. By additionally capturing the fingerprint, the user's identity can be verified using biometric data, for example.

[0023] It is advantageous if the evaluation device has a first evaluation path for evaluating the signals detected by the first sensor device and a second evaluation path for evaluating the signals detected by the second sensor device. Providing separate evaluation paths can, for example, improve the functional safety of the evaluation device. A fault occurring in the evaluation device generally affects only one of the two evaluation paths, but not both evaluation paths simultaneously. This reduces the risk of an incorrect response due to a technical fault.

[0024] Preferably, the first evaluation path comprises a first microcontroller for evaluating the signals supplied by the first sensor device, and the second evaluation path comprises a second microcontroller for evaluating the signals supplied by the second sensor device. By appropriately programming the microcontrollers, evaluation parameters such as response sensitivity, minimum response time, etc., can be defined.

[0025] Preferably, the first evaluation path is configured to generate a first detection signal indicating touch inputs detected by the first sensor device, and the second evaluation path is configured to generate a second detection signal indicating touch inputs detected by the second sensor device. The evaluation device is configured to combine the two detection signals into an overall detection signal that only indicates a touch input from the user if both the first detection signal and the second detection signal indicate a touch input from the user. Each of the two evaluation paths provides a separate detection signal. The detection signals based on different detection methods are combined by the evaluation device into an overall detection signal.

[0026] According to a preferred embodiment, the evaluation device is designed to combine the two detection signals using an AND operation. An AND operation represents the simplest way to combine the detection signals supplied by the evaluation paths.

[0027] According to a preferred embodiment, the evaluation device is designed to detect specific disturbances in the detected signals using signatures stored in the evaluation device and associated with these disturbances. For example, if a liquid contacts the input device, only the first sensor device responds, while the second sensor device delivers no or only a weak signal. During the evaluation, such a response behavior can be assigned to a specific signature.

[0028] Preferably, the input device is designed as a structural unit. In particular, the input device can be implemented, for example, as a compact component that recognizes touch inputs with high reliability and is therefore suitable for applications with high security requirements.

[0029] The cover plate is preferably designed as a rigid cover plate. Further preferably, the cover plate is designed as a fully or partially transparent cover plate. For example, signal lights or display elements that are visible through the cover plate can be arranged beneath the cover plate.

[0030] It is advantageous if the cover plate has a recess on the side facing the user, in an area where the first detection area and the second detection area overlap. The recess can, for example, serve as a guide for the user as to where he or she can make a touch input.

[0031] Preferably, the input device comprises a tactile feedback device configured to output tactile feedback whenever both sensor devices detect a touch input. The tactile feedback serves as confirmation to the user that their touch input has been recognized by the input device.

[0032] According to a preferred embodiment, the input device comprises a display unit which is arranged on the side of the cover plate facing away from the user in a third region of the cover plate, wherein the cover plate is at least partially transparent in the third region. The display unit preferably comprises a display unit. More preferably, the display unit is a display unit. On the display unit, for example, information about the respective transaction can be shown, the execution of which can then be authorized, for example, by the user using the input device. The input device and the display unit are preferably attached to one and the same continuously designed cover plate.For example, in an input terminal, all operating elements and display elements, including the input device according to embodiments of the invention, can be mounted on a common cover plate, preferably on the side of the cover plate facing away from the user. This enables a design with a continuous, smooth surface without recesses, cracks, or gaps. The cover plate protects the operating and display elements from tampering and damage, and it also facilitates cleaning of the device.

[0033] It is advantageous if the third area of ​​the cover plate and the first and second detection areas do not overlap each other.

[0034] Further preferably, the information displayed on the display unit is visible through the cover plate. In particular, the display unit can display, for example, information relating to a transaction, which can then be confirmed or approved by the user, for example, using the input device.

[0035] It is advantageous if the display unit includes a touch function designed to detect user touch inputs in the third area of ​​the cover plate using projective capacitive detection. The display unit can be designed, for example, as a projective capacitive touchscreen. For example, a selection menu in an operating terminal can be operated using such a touchscreen. The input device according to the embodiments of the invention, which is designed in particular for increased security requirements, can then be used as a supplement to the touchscreen for the approval or confirmation of transactions.

[0036] According to a preferred embodiment, the sensor unit has a double-sided structured circuit board which has a first side facing the cover plate and a second side facing away from the cover plate, wherein an electrode arrangement of the first sensor device is arranged on the first side of the circuit board, and wherein at least one component of the evaluation device is arranged on the second side of the circuit board. The double-sided structured circuit board, on the one hand, provides the electrode arrangement required for capacitive detection on the first side of the circuit board facing the cover plate. On the other hand, the double-sided structured circuit board serves as a carrier substrate for the components of the evaluation device, for example the programmable microcontroller. The double-sided structured circuit board enables, for example, a structural integration of sensor and evaluation devices.In this way, a compact and space-saving design of the sensor unit is created.

[0037] According to a preferred embodiment, the first sensor device is designed to detect the self-capacitance of electrodes of the electrode arrangement. In this embodiment, the change in the capacitance of the respective electrode relative to ground is detected.

[0038] Preferably, the electrode arrangement comprises a first electrode and a second electrode. Preferably, the first sensor device is designed to detect the self-capacitance of the first and second electrodes. This introduces redundancy in the capacitive detection. Both electrodes are arranged on the first side of the circuit board facing the cover plate.

[0039] According to a preferred embodiment, the second sensor device is arranged on the second side of the circuit board. This enables, for example, structural integration of the first sensor device, the second sensor device, and the evaluation device using the double-sided structured circuit board.

[0040] It is advantageous if the circuit board has an opening, wherein the second sensor device is designed to emit light through the opening and to receive light reflected back through the opening. The second sensor device is attached to the second side of the circuit board facing away from the cover plate. It is therefore advantageous to provide an opening in the circuit board, wherein the second sensor device is preferably arranged and designed such that the second sensor device radiates light through the opening onto the cover plate and can receive and evaluate light reflected back through the opening. The opening is preferably provided centrally or approximately centrally on the circuit board. Further preferably, on the first side of the circuit board facing the cover plate, the opening is surrounded by the first electrode and the second electrode of the first sensor device.Preferably, the first electrode and the second electrode are arranged mirror-symmetrically to one another on the first side of the circuit board. Further preferably, the first electrode and the second electrode are designed as half-shell-shaped electrodes that surround the opening in a mutually opposite relationship. This can result, for example, in a concentric and coaxial arrangement of the components used for optical and capacitive detection.

[0041] According to another preferred embodiment, the first sensor device can be designed to detect the mutual capacitance between electrodes of the electrode arrangement. In this embodiment, the change in the capacitance measurable between different electrodes is detected.

[0042] According to a preferred embodiment, the sensor unit is designed as a structural unit that can be attached to the side of the cover plate facing away from the user. In this way, the sensor unit can be used, for example, on an existing cover plate, for example, in a customer-specific installation environment. In particular, it is possible, for example, to retrofit the sensor unit to a cover plate in order to provide, for example, an operating element for increased safety requirements.

[0043] It is advantageous if the sensor unit can be subsequently attached to the side of the cover plate facing away from the user. Preferably, the sensor unit can be attached to the side of the cover plate facing away from the user without damaging or destroying the cover plate.

[0044] Preferably, the first sensor device and the second sensor device are configured as a structural unit that can be attached to the side of the cover plate facing away from the user. For example, the first and second sensor devices can be implemented as a structural unit, while the evaluation device, for example, is separated from the structural unit and implemented as a separate assembly.

[0045] Preferably, the sensor unit is designed to provide the functionality of a push button switch. Brief description of the drawings

[0046] Further advantageous embodiments are described in more detail below with reference to several exemplary embodiments shown in the drawings, to which the invention is not, however, limited.

[0047] They show schematically: Fig. 1 shows a schematic representation of the two detection methods of the input device. Fig. Figure 2A shows a front view of an input device. Fig. Figure 2B shows a side view of the input device. Fig. 3 shows a concrete design of the input device. Fig. 4 shows the evaluation electronics arranged on the second side of the circuit board. Fig. Figure 5 illustrates the capacitive detection and the optical detection of touch events. Fig. 6 shows an embodiment in which the sensor unit can be attached as a structural unit to a cover plate. Fig. 7 shows an embodiment in which a display unit and a sensor unit are attached to a continuous cover plate. Fig. 8 shows an embodiment in which an electrode structure is provided on the cover plate, which covers both a display unit and an optical sensor device. Detailed description of embodiments of the invention

[0048] In the following description of preferred embodiments of the present invention, like reference numerals denote like or comparable components.

[0049] In Fig. 1 schematically illustrates the functionality of an input device according to embodiments of the present invention. In order to enable reliable detection of a user's touch inputs, two different technologies for detecting touch inputs are combined, namely, optical detection of the touch inputs and capacitive detection of the touch inputs. For this purpose, an optical sensor device 4 and a capacitive sensor device 6 are arranged on the touch surface 2. The optical sensor device 4 is designed to detect touch inputs made by the user on the touch surface 2 using an optical detection method. For this purpose, the optical sensor device 4 can comprise, for example, a retro-reflective sensor, a forked light barrier, a time-of-flight sensor, or a LIDAR sensor. If the optical sensor device 4 detects a touch input, this is indicated in the Fig. 1 shown example by a first LED 8.

[0050] The capacitive sensor device 6 is designed to detect touch inputs made by the user on the touch surface 2 by means of a capacitive detection method.

[0051] Such capacitive detection methods are based on the detection of a capacitance change that occurs whenever the user performs a touch input. When the capacitive sensor device 6 detects a touch input, this is indicated in the Fig. 1 is indicated by a second LED 10. Both the detection signal supplied by the optical sensor device 4 and the detection signal supplied by the capacitive sensor device 6 are fed to the AND gate 12. The total detection signal 14 at the output of the AND gate 12 only indicates a touch input from the user if both the optical sensor device 4 and the capacitive sensor device 6 detect a touch input. Fig. In this case, in the example shown in Figure 1, a tactile feedback is output by means of a tactile feedback device 16, for example an exciter, to indicate to the user that his touch input has been recognized.

[0052] The input device according to the embodiments of the present invention is designed to detect a touch input only when two detection methods based on different operating principles, which preferably do not interact with each other, independently detect a touch input. By combining two different detection methods for detecting touch inputs, the probability that a user's touch inputs can be correctly detected and distinguished from interference is significantly increased.

[0053] The active principles of Fig. 1 is therefore particularly suitable for use in security-critical applications where the correct recognition of user touch inputs is particularly important. An example of such a security-critical application is ATMs or terminals used to initiate relevant business transactions. To increase the security when processing such transactions, a Fig. 1 operating input device. Another example of a safety-critical application is operating devices and control panels for technical machines such as presses, punching machines, etc. Here, the use of the input device according to the embodiments of the invention can prevent the risk of incorrect operation and the risk of erroneous triggering of processes. Another example is medical technology devices, for example, intensive care devices, ventilators, X-ray machines, etc., where incorrect inputs could be detrimental to the patient.

[0054] Fig. Figure 2A shows a view of a system based on the principles of Fig. 1 based input device 18 from the front, while Fig. 2B shows a side view of the input device 18. The input device 18 comprises a cover plate 20, wherein the touch surface 2 is characterized by a recess 22 provided in the cover plate 20. The optical sensor device 4 and the capacitive sensor device 6 can be seen on the side of the cover plate 20 facing away from the user. The first LED 8 and the second LED 10 are arranged below or on the cover plate 20. If a touch input is consistently detected by both the optical sensor device 4 and the capacitive sensor device 6, this can be displayed to the user, for example, by means of the tactile feedback device 16.

[0055] With the aid of the input device 18 according to the embodiments of the invention, actual touch inputs by the user can be reliably distinguished from other events that are often falsely recognized as touch inputs. For example, the input device 18 does not respond if it comes into contact with flowing or stagnant liquids. Although the presence of liquids triggers the capacitive detection, the optical detection does not respond. This also applies to saline liquids such as blood. The input device 18 also does not respond during cleaning processes that involve contact with cleaning agents. If non-conductive objects come into contact with the touch surface 2, this generally does not trigger an activation because in this case only the optical detection, not the capacitive detection, responds.Therefore, operation of the input device 18 is not possible while wearing thick gloves. However, the sensitivity of the capacitive detection can be calibrated so that the user can make touch inputs even when wearing thin latex gloves, which are then recognized by both the optical and capacitive detection. This makes it possible, for example, to operate medical devices both with and without latex gloves. By appropriately adjusting the sensitivity of the capacitive and optical detection, it is also possible to ensure that the input device 18 only responds when the surface of the cover plate 20 is actually touched. This can further reduce the risk of unintentional inputs. Furthermore, the input device 18 should not be triggered even if the touch surface 2 briefly comes into contact with moving objects.To prevent triggering in such cases, a minimum response time can be defined in the evaluation device, for example, which must be exceeded for both optical and capacitive detection before a touch input is recognized.

[0056] In Fig. 3 shows an advantageous design of the input device 18. The input device 18 comprises the cover plate 20 and a sensor unit 24 attached to the side of the cover plate 20 facing away from the user. The sensor unit 24 is preferably designed as a compact structural unit that is attached to the rear side of the cover plate 20 facing away from the user. The sensor unit 24 comprises an electronic assembly 26 and the optical sensor device 4 attached to the electronic assembly 26. The optical sensor device 4 has a light source 28, preferably an infrared light source, which can be designed, for example, as an LED or as a laser unit. The optical sensor device 4 also has a receiving unit 30.

[0057] The electronic assembly 26 comprises a printed circuit board 32 structured on both sides with an approximately centrally located opening 34. On the first side of the printed circuit board 32 facing the cover plate 20, an electrode arrangement with a first electrode 36 and a second electrode 38 is arranged, which is part of the capacitive sensor device 6. The evaluation electronics for the optical and capacitive sensor devices are arranged on the second side of the printed circuit board 32 facing away from the cover plate 20.

[0058] The touch area of ​​the cover plate 20 is identified by the recess 22. Within the recess 22, a translucent area or recess 40 is provided through which a light beam emitted by the light source 28 can pass. When the user touches the recess 22 with their finger, the light beam is reflected back to the receiving unit 30 and detected by the optical sensor device 4.

[0059] Fig. 4 shows the second side of the circuit board 32, facing away from the cover plate 20, with the evaluation electronics. The evaluation electronics are used to implement the evaluation device, which is designed to further process the signals provided by the sensor devices 4 and 6. The evaluation electronics comprise two separate evaluation paths, a first evaluation path for capacitive detection and a second evaluation path for optical detection. The first evaluation path comprises a first microcontroller 42 and the second evaluation path comprises a second microcontroller 44. By providing two separate evaluation paths, the functional safety requirements according to IEC 61508 can be met. Furthermore, the optical sensor device 4 can be seen on the second side of the circuit board 32. A two-pin socket 46 is provided for supplying voltage to the sensor unit 24.The two connector sockets 48 and 50 serve as interfaces for programming the first microcontroller 42 and the second microcontroller 44. In addition, the tactile feedback device 16 can be seen.

[0060] Fig. 5 shows a section through the cover plate 20 and the sensor unit 24.

[0061] Based on Fig. 5, the capacitive detection of touch events will be described first. The first electrode 36 and the second electrode 38 are mounted on the first side of the double-sided structured circuit board 32 facing the cover plate 20. The first electrode 36 is supplied with a pulsed or modulated control signal. If the detection range of the capacitive detection, which is shown in Fig. 5, as illustrated by lines 52, for example, the user's finger is present, the capacitance between the first electrode 36 and ground changes. Likewise, the capacitance between the second electrode 38 and ground changes. The capacitance change caused by the presence of the finger, which can be in the range of up to a few picofarads, for example, can be detected by the evaluation electronics. If the change in capacitance exceeds a defined threshold value, the capacitive sensor device 6 detects a touch event.

[0062] Next, we will use Fig. 5, the optical detection of touch events will be described. The optical sensor device 4 is mounted on the second side of the circuit board 32 such that the light source 28 and the receiving unit 30 protrude into the opening 34 of the circuit board 32. The cover plate 20 comprises the light-permeable region or recess 40, through which a light beam 54 emitted by the light source 28 can pass. The optical sensor device 4 can be designed, for example, as a retro-reflective light barrier or as a time-of-flight (ToF) sensor. If the user's finger is located within the detection range of the optical detection, the light beam 54 emitted by the light source 28 is reflected by the user's finger, and the reflected light beam 56 is detected by the receiving unit 30. The optical sensor device 4 can, in particular, be designed as a time-of-flight (ToF) sensor.In this case, the light source 28 is designed to emit a pulsed or modulated light signal. The propagation time can be determined based on the time offset between the emitted light beam 54 and the reflected light beam 56. If the propagation time of the light signal lies within a predefined propagation time range, which results from the distance between the light source 28 and the finger, the optical sensor device 4 detects a touch input.

[0063] As a further alternative, the optical sensor device 4 can be designed as a LIDAR sensor. In a LIDAR sensor, a predetermined detection area is scanned using a laser beam so that a three-dimensional profile of the objects located in the detection area can be created. For this purpose, the LIDAR sensor comprises a controllable deflection unit. Based on the captured 3D profile, the LIDAR sensor can, for example, detect that the object located in the detection area is a user's finger. In this way, the selectivity in detecting user touch inputs can be further improved.

[0064] To suppress an unintentional response of the optical sensor device 4 to extraneous light, a narrowband filter, for example, whose bandwidth is adapted to the bandwidth of the light signal used, can be arranged in the receiving channel upstream of the receiving unit 30. The light signal can, in particular, be an infrared light signal. Another possibility for suppressing extraneous light influences is to modulate the transmitted signal according to a predetermined modulation and to enable the receiving channel according to this modulation. This possibility for distinguishing between the wanted signal and the background is referred to as "gating."

[0065] In Fig. 6 shows how the Fig. 3, the sensor unit 24 can be attached to the side of a cover plate 58 facing away from the user to enable reliable detection of touch inputs. The cover plate 58 is translucent or has a recess at least at the point where the light signals required for optical detection are emitted or received. The sensor unit 24 is preferably designed as a standalone structural unit. The sensor unit 24 can, for example, also be subsequently attached to the side of a cover plate facing away from the user.

[0066] In the Fig. 6, the evaluation device is integrated into the sensor unit 24. However, the evaluation device could be Fig. 6, the device can also be separated from the structural unit attached to the cover plate 58 and provided, for example, in the form of a separate evaluation device.

[0067] In addition to the sensor unit 24, further operating elements and / or display units can be arranged on the cover plate 58. Such an embodiment is shown in Fig. 7 shown. In Fig. 7, the sensor unit 24 is arranged in a first region of the cover plate 58. In addition, a display unit 60, for example a display unit, such as an LCD or OLED display, is arranged in a third region, which is different from the first region and does not overlap with the first region. The cover plate 58 is at least partially transparent in the third region, so that the content displayed on the display unit 60 is visible to the user through the cover plate 58. The display unit 60 can be designed either as a simple display unit or as a capacitive touchscreen designed to detect touch inputs from the user in the third region of the cover plate 58. However, lower security standards apply to these touch inputs detected in the third region of the cover plate 58 than to the touch inputs detected by the sensor unit 24.

[0068] Also in the Fig. 7, the evaluation device can also be separated from the sensor unit 24 attached to the cover plate 58.

[0069] In Fig. Figure 8 shows a further embodiment of an input device comprising a cover plate 62 with an electrode structure 64 arranged in a first region of the cover plate 62 for projective capacitive touch detection. A display unit 66 is arranged in a first partial region of the electrode structure 64. The content displayed on the display unit 66 is recognizable to the user because both the cover plate 62 and the electrode structure 64 are at least partially transparent within the first partial region. Touch inputs made by the user in the region of the display unit 66 can be recognized by the electrode structure 64 by means of capacitive touch detection.

[0070] An optical sensor device 68 for optically detecting touch inputs is arranged in a second partial region of the electrode structure 64, which is different from the first partial region and does not overlap with the first partial region. The cover plate 62 and the electrode structure 64 are completely or partially translucent or have a recess, at least at the location where the light signals required for optical detection are emitted or received.

[0071] The input device has an evaluation device which is designed to generate an overall detection signal which only indicates a touch input of the user in the second partial region of the electrode structure 64 if a touch input is detected both by means of the electrode structure 64 and by the optical sensor device 68 within the detection range of the optical sensor device 68.

[0072] The features disclosed in the above description, the claims and the drawings may be important both individually and in any combination for the realization of the invention in its various embodiments.

Claims

[1] An input device (18) for detecting touch inputs from a user, the input device (18) comprising: - a cover plate (20, 58), - a first sensor device (6) which is arranged on the side of the cover plate (20, 58) facing away from the user and is designed to detect touch inputs from the user in a first detection area on the side of the cover plate (20, 58) facing the user by means of a detection method based on capacitive detection, - a second sensor device (4) which is arranged on the side of the cover plate (20, 58) facing away from the user and which is designed to detect touch inputs from the user in a second detection area on the side of the cover plate (20, 58) facing the user by means of an optical detection method, wherein the second sensor device (4) is designed to emit light and receive reflected light when carrying out the detection method, - wherein the cover plate (20, 58) is at least partially completely or partially transparent to the light emitted by the second sensor device (4) or has a recess (40) for the light emitted by the second sensor device (4), and - where the first detection area and the second detection area overlap completely or partially, - an evaluation device which is designed to evaluate signals provided by the sensor devices (4, 6) and to generate an overall detection signal (14) which only indicates a touch input by the user if both the signal provided by the first sensor device (6) and the signal provided by the second sensor device (4) indicate a touch input by the user. [2] Input device (18) according to claim 1, characterized by that the first sensor device (6) comprises an electrode arrangement for transmitting and receiving an electromagnetic field. [3] Input device (18) according to claim 1 or claim 2, characterized by that the optical detection method is one of the following: LIDAR, optical detection based on the time-of-flight measurement principle, detection by means of a reflex light barrier or fork light barrier. [4] Input device (18) according to one of the preceding claims, characterized by that the second sensor device (4) comprises a LIDAR sensor which is designed to scan the second detection area by means of a laser. [5] Input device (18) according to one of the preceding claims, characterized by in that the second sensor device (4) comprises an optical time-of-flight sensor which is designed to emit a light signal and to receive reflected light, wherein the input device (18) is designed to detect touch inputs of the user using a time-of-flight analysis of the light. [6] Input device (18) according to one of the preceding claims, characterized by that the evaluation device has a first evaluation path for evaluating the signals detected by the first sensor device (6) and a second evaluation path for evaluating the signals detected by the second sensor device (4). [7] Input device (18) according to one of the preceding claims, characterized by that the input device (18) is designed as a structural unit. [8] Input device (18) according to one of the preceding claims, characterized by in that the input device (18) comprises a display unit (60) which is arranged on the side of the cover plate (20, 58) facing away from the user in a third region of the cover plate (20, 58), wherein the cover plate (20, 58) is at least partially transparent in the third region. [9] Input device (18) according to claim 8, characterized by that the third region of the cover plate (20, 58) and the first and second detection regions do not overlap each other. [10] Input device (18) according to claim 8 or claim 9, characterized bythat the display unit (60) comprises a touch function which is designed to detect touch inputs from the user in the third area of the cover plate (20, 58) by means of projective capacitive detection. [11] A sensor unit (24) for detecting touch inputs of a user, which has a first sensor device (6), a second sensor device (4) and an evaluation device, wherein the sensor unit (24) can be attached to a side of a cover plate (20, 58) facing away from the user, - wherein the first sensor device (6) is designed to detect touch inputs of the user in a first detection area on the side of the cover plate (20, 58) facing the user by means of a detection method based on capacitive detection, - wherein the second sensor device (4) is designed to detect touch inputs of the user in a second detection area on the side of the cover plate (20, 58) facing the user by means of an optical detection method, wherein the second sensor device (4) is designed to emit light and receive reflected light when carrying out the detection method, - wherein the first detection area and the second detection area overlap completely or partially, and - wherein the evaluation device is designed to evaluate signals provided by the sensor devices (4, 6) and to generate an overall detection signal (14) which only indicates a touch input by the user if both the signal provided by the first sensor device (6) and the signal provided by the second sensor device (4) indicate a touch input by the user. [12] Sensor unit (24) according to claim 11, characterized by that the optical detection method is one of the following: LIDAR, optical detection based on the time-of-flight measurement principle, detection by means of a reflex light barrier or fork light barrier. [13] Sensor unit (24) according to claim 11 or claim 12, characterized by in that the sensor unit (24) has a double-sided structured printed circuit board (32) which has a first side facing the cover plate (20, 58) and a second side facing away from the cover plate (20, 58), wherein an electrode arrangement of the first sensor device (6) is arranged on the first side of the printed circuit board (32), and wherein at least one component of the evaluation device is arranged on the second side of the printed circuit board (32). [14] Sensor unit (24) according to one of claims 11 to 13, characterized bythat the sensor unit (24) is designed as a structural unit which can be attached to the side of the cover plate (20, 58) facing away from the user. [15] Sensor unit (24) according to one of claims 11 to 14, characterized by that the sensor unit (24) can be subsequently attached to the side of the cover plate (20, 58) facing away from the user. [16] An input device (18) for detecting touch inputs from a user, the input device (18) comprising: - a cover plate (20, 58), - a sensor unit (24) according to one of claims 11 to 15 mounted on the side of the cover plate (20, 58) facing away from the user in a first region, wherein the cover plate (20, 58) is at least partially completely or partially transparent to the light emitted by the second sensor device (4) or has a recess (40) for the light emitted by the second sensor device (4), - a display unit (60) arranged on the side of the cover plate (20, 58) facing away from the user in a third region, wherein the third region is different from the first region and the first region and the third region do not overlap, wherein the cover plate (20, 58) is at least partially transparent in the third region. [17] An input device for detecting touch inputs from a user, the input device comprising: - a cover plate (62), - a first sensor device (6) comprising an electrode structure (64) arranged in or on a first region of the side of the cover plate (62) facing away from the user, wherein the first sensor device (6) is designed to detect touch inputs from the user in a first detection region on the side of the cover plate (62) facing the user by means of a detection method based on capacitive detection, - a display unit (66) for displaying contents, wherein the display unit (66) is arranged on a first partial area of the first area of the cover plate (62), - wherein the cover plate (62) and the electrode structure (64) are completely or partially transparent in the first partial region of the first region of the cover plate (62), wherein contents displayed on the display unit (66) are completely or partially recognizable through the cover plate (62) and the electrode structure (64), - a second sensor device (4) arranged on a second partial region of the first region of the cover plate (62), wherein the second partial region does not overlap with the first partial region, wherein the second sensor device (4) is designed to detect touch inputs of the user in a second detection region on the side of the cover plate (62) facing the user by means of an optical detection method, wherein the second sensor device (4) is designed to emit light and receive reflected light when carrying out the detection method, - wherein the cover plate (62) and the electrode structure (64) are at least partially completely or partially transparent to the light emitted by the second sensor device (4) and / or have one or more recesses for the light emitted by the second sensor device (4), - an evaluation device which is designed to evaluate signals provided by the sensor devices (4, 6) and to generate an overall detection signal (14) which only indicates a touch input by the user if both the signal provided by the first sensor device (6) and the signal provided by the second sensor device (4) indicate a touch input by the user. [18] Method for detecting touch inputs of a user by means of a sensor unit (24) which is designed to detect touch inputs of the user on a side of a cover plate (20, 58) of the sensor unit (24) facing the user, wherein the sensor unit (24) is arranged on the side of the cover plate (20, 58) facing away from the user, wherein the method comprises the following steps - detecting touch inputs from the user in a first detection area on the side of the cover plate (20, 58) facing the user by means of a detection method based on capacitive detection, - detecting touch inputs from the user in a second detection area on the side of the cover plate (20, 58) facing the user by means of an optical detection method, - generating an overall detection signal (14) that indicates a user touch input only when both the capacitive detection-based detection method and the optical detection method detect a user touch input. [19] Method for assembling an input device (18) for detecting touch inputs from a user, the method comprising the following step: - subsequently attaching a sensor unit (24) according to one of claims 11 to 15 to the side of a cover plate (20, 58) facing away from the user in such a way that the first sensor device (6) detects touch inputs from the user in a first detection area on the side of the cover plate (20, 58) facing the user and the second sensor device (4) detects touch inputs from the user in a second detection area on the side of the cover plate (20, 58) facing the user, wherein the first detection area and the second detection area overlap completely or partially.

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