Input method for a touch-sensitive input device

Abstract

Input procedure comprising the following steps: Providing an input device (1) comprising an input surface (8) and a scanner (2) which is oriented to detect a touch of a finger on the input surface (8) forming a touch surface (11a, 11b) and an evaluation unit (3) to assign a control and / or switching function to a movement of the touch surface (11a, 11b) on the input surface (8); Operation of the input device (1) in an identification mode in which a surface structure of the contact surface (11a, 11b) of the finger lying in the input surface (8) during contact is detected by the scanner (2) and evaluated by the evaluation unit (3) to generate biometric data; Operation of the input device (1) in a first detection mode in which a first partial area (9a) of the input surface (8), each covered by the contact surface (11a, 11b), is repeatedly fully or completely detected by means of the scanner (2) and associated first data are transmitted to the evaluation unit (3); Operation of the input device (1) in a second detection mode, in which a second partial area (9b) of the input surface (8), each covered by the contact surface (11a, 11b), is repeatedly fully or completely detected by means of the scanner (2) and the associated second data is transmitted to the evaluation unit (3); Evaluating the first and second data by the evaluation unit (3) to obtain a first evaluation result and a second evaluation result, in order to assign a control and / or switching function to the relative movement of the contact surface (11a, 11b) only if there is a predetermined minimum agreement between the first evaluation result and the second evaluation result, characterized in that the evaluation unit (3) comprises a primary unit (3a) located closest to the scanner (2), which evaluates at least the first data, and a secondary unit (3b) connected to the first unit (3a) via a data communication link, which evaluates at least the first data and is superior to the primary unit (3a). that the secondary unit (3b) is designed to reset the primary unit if there is a lack of minimum agreement between its evaluation result and the evaluation result of the primary unit (3a).

Description

[0001] The present invention relates to an input method for a touch-sensitive input device having an input surface and a scanner configured to detect a touch of the input surface. The input method and the input device are configured to detect the surface structure of a finger in an identification mode and enable finger navigation, for example, cursor control.

[0002] Various touch-sensitive input devices with associated input surfaces are known from the prior art. These devices are suitable for performing fingerprint recognition in at least a partial area of ​​the input surface. Finger navigation then takes place in the remaining area of ​​the input surface of the touch-sensitive input device.

[0003] EP 1 947 590 B1 discloses a device for input and fingerprint recognition, wherein a first region and a second region of a touch surface are provided, and fingerprint recognition takes place in the second region. A data processor is configured to selectively operate the touch surface in a touch input mode or in a fingerprint detection mode, hereinafter also referred to as identification mode. In the touch input mode, the second region is operated at a resolution comparable to that of the first region in order to detect a touch input anywhere on the touch surface. In the fingerprint mode, the data processor is configured to detect the second region with a higher resolution in order to detect a fingerprint thereon.

[0004] From US 2012 / 0105081 A1 an input method according to the preamble of claim 1 is known, namely that capacitive sensors can be able to determine the presence and location of a touch of a fingerprint pattern.

[0005] From DE 100 04 965 A1 a device for the manual operation of devices in a vehicle is known, which is connected to the steering wheel and has operating elements that enable two-dimensional movement and / or three-dimensional movement and activation on a display.

[0006] From US 2003 / 0112226 A1 a touch-sensitive detector is known, comprising a detection surface and a conductive element as well as a first and second set of electrodes, wherein each set of electrodes comprises at least one electrode extending parallel to the detection surface and wherein each electrode is electrically insulated.

[0007] Especially when using a finger-based input device in a motor vehicle, there is a fundamental need to comply with ISO 26262. The implementation of this standard is intended to ensure the functional safety of a system with electrical / electronic components in the motor vehicle. With the ever-increasing complexity of electronic components in vehicles, the possibility and risk of malfunctions also increases. If a safety-relevant component is affected by such a malfunction, in the worst case scenario, people could be injured. Therefore, ISO 26262 defines safety objectives. This means that suitable measures and processes must be implemented to prevent systematic errors, and appropriate additional product requirements must be implemented to control technical errors.In the case of an input device for finger navigation in a motor vehicle, these requirements are difficult to meet, since the available installation space, particularly in a steering wheel of a motor vehicle, precludes a completely redundant design of the input device, for example, redundant detection of the comparatively small input area by several scanners is impossible anyway.

[0008] The object of the invention is therefore to provide an input method for a touch-sensitive input device which is suitable for enabling finger navigation reliably, i.e. with improved prevention of malfunctions, even with limited installation space and a small input area. This object is achieved by an input method according to claim 1 and by an input device according to the independent device claim. Advantageous embodiments are each the subject of the dependent claims. It should be noted that the features individually listed in the patent claims can be combined with one another in any desired, technologically expedient manner and demonstrate further embodiments of the invention. The description, particularly in conjunction with the figures, further characterizes and specifies the invention.

[0009] According to the invention, an input device is provided. The input device has an input surface and a scanner. According to the invention, the scanner is aligned and designed such that it detects contact of a finger on the input surface. The finger forms a contact surface on the input surface. For example, an optical scanner, in particular an infrared scanner, is provided. In particular, the scanner has a plurality of sensor elements forming an array, preferably a two-dimensional array, which detects and thus defines the input surface. The sensor elements can preferably be evaluated individually and / or can be evaluated at least as bundles and / or line-by-column. According to the invention, a capacitive scanner, i.e. one that detects the input surface capacitively, is preferably provided. For example, the scanning area and thus the input surface is determined by a two-dimensional array of measuring capacitors.Preferably, it is a capacitive fingerprint scanner, as disclosed, for example, in DE 103 14 682 A1, the disclosure content of which is hereby included.

[0010] According to the invention, an evaluation unit is further provided to assign a control and / or switching function to a movement of the touch surface on the input surface. The evaluation unit is arranged, for example, at least partially directly adjacent to the scanner.

[0011] The input method according to the invention is particularly suitable for input devices in which the scanning area and thus the input surface can be completely covered by a finger resting thereon, and in particular for input devices with an input surface of less than or equal to 2 cm 2 , preferably less than or equal to 1.2 cm 2 , more preferably less than or equal to 0.25 cm 2For example, the input area is rectangular, oval or round.

[0012] The input method according to the invention provides for operation of the input device in an identification mode. In said identification mode, a surface structure of the finger touch surface located on the input surface during contact is detected by the scanner and evaluated by the evaluation unit to generate biometric data. The data is stored, for example, in a non-volatile memory.

[0013] Furthermore, according to the invention, the input device is operated in a first detection mode in which a first partial area of ​​the input surface covered by the touch surface is detected several times completely or over its entire area by means of the scanner and associated first data are transmitted to the evaluation unit.

[0014] According to the invention, the input device is operated in a second detection mode, in which a second partial area of ​​the input surface, each covered by the touch surface, is repeatedly scanned completely or over its entire area by the scanner, and associated second data is transmitted to the evaluation unit. Operation in the first and second detection modes is performed, for example, simultaneously or intermediarily.

[0015] In an evaluation step following each of the acquisition steps, the first data and second data are evaluated by the evaluation unit to obtain a first evaluation result and a second evaluation result, so that a control and / or switching function is assigned to the relative movement of the contact surface only if there is a predetermined minimum agreement between the first evaluation result and the second evaluation result.

[0016] "Full-area detection" within the meaning of the invention means the complete detection of a contiguous sub-area, for example, by evaluating all sensor elements of the scanner assigned to the respective sub-area and arranged adjacent to one another. "Complete detection" within the meaning of the invention means the detection of a not necessarily contiguous sub-area, which, for example, is formed from segments or individual sensor elements distributed across the input area.

[0017] The evaluation is carried out, for example, using an image comparison method, such as a differential image comparison method or an image correlation method, in which at least two images or partial images of the respective sub-area taken one after the other are evaluated or compared with one another. "Image" or "images" in the sense of the invention does not necessarily imply an optical detection of the respective sub-area, but is to be interpreted broadly and means a related detection of all sensor elements of the scanner assigned to the respective sub-area, for example in the form of a measured value matrix. The change in the position of at least one characteristic point or a characteristic structure of the detected surface structure within the sub-area is assigned a relative movement, which in turn is converted into a control and / or switching function.

[0018] The functional reliability can be increased by the operation of the input device which evaluates different parts of the input surface.

[0019] According to a preferred embodiment of the input method, the first sub-area and the second sub-area are arranged so as not to overlap, i.e., they are spatially separated from one another. This achieves improved verification, since the detection occurs through spatially different areas of the scanner's input surface and thus through different sensor elements, and furthermore, the detection occurs on different structures of the finger's surface structure.

[0020] According to the invention, the evaluation unit is hierarchically structured and has a primary unit, also called a sensor controller, which is assigned to the scanner and evaluates at least the first data, and a secondary unit, also called a host controller, which communicates with the first unit via a data communication connection, preferably a bidirectional and / or encrypted data communication connection, evaluates at least the first data and is superior to the primary unit. This achieves improved verification. For secure verification, both the first and the second data are evaluated by the primary unit and the secondary unit. In a further simplified embodiment, the first data are evaluated exclusively by the primary unit and the second data are evaluated exclusively by the secondary unit.

[0021] According to a preferred embodiment, the primary and / or secondary unit are functionally monitored. For example, the primary and / or secondary unit comprises an A / D converter. For monitoring its functionality, a predefined reference voltage is converted and thus digitized by the converter, and the associated digital value is compared with the value corresponding to the predefined reference voltage. If there is insufficient agreement, the secondary unit diagnoses a malfunction of the primary unit, and assignment to a switching or control function is prevented.

[0022] According to the invention, the secondary unit is designed to reset the primary unit if there is no minimum agreement between its evaluation result and the evaluation result of the primary unit.

[0023] Preferably, the input device is operated simultaneously in the first acquisition mode and the second acquisition mode. In other words, the first data and second data are acquired by simultaneously acquiring the first and second partial areas, respectively. However, embodiments are conceivable in which the first and second data are generated in chronological order by a sequence of acquisition steps.

[0024] According to a preferred embodiment, the evaluation unit evaluates the first and second data using different algorithms. For example, the first data is determined using a differential image comparison method, and the second data is determined using an image correlation method. To achieve a high degree of verification and functional monitoring, both the first data and the second data are evaluated using different algorithms.

[0025] According to a preferred embodiment, the assignment to a control and / or switching function is additionally verified based on the biometric data obtained in identification mode. In other words, the assignment only occurs if there is a minimum match between the biometric data determined in identification mode and the stored biometric data.

[0026] The two detection modes are used in particular for evaluating comparatively slow finger movements across the scan area. For example, these are performed provided the surface structure, and thus the touch surface, does not exceed an average speed relative to the input surface of 400 mm / s, preferably 200 mm / s.

[0027] In one embodiment of the method, the first sub-area is located in the center of the input area, i.e., centrally and surrounded by other areas of the input area. Particularly preferably, the sensor elements assigned to this area are evaluated individually in the first sub-area. The first sub-area is designed so that a surface structure of a finger can be reliably detected.

[0028] According to this embodiment, the second sub-area is provided within the edge area adjacent to the first sub-area.

[0029] According to a preferred embodiment, the scanner has an array of sensor elements, which are selected depending on the input mode in order to be assigned to the first sub-area or the second sub-area.

[0030] The input method according to the invention and the input device according to the invention are preferably suitable for use in a motor vehicle, in particular as a component of a steering wheel, for example as a multifunctional input device which is at least partially integrated into a spoke of a steering wheel.

[0031] The invention is explained in more detail with reference to the following figures. These figures are to be understood as examples only and represent preferred embodiments. They show: Fig. 1 shows an embodiment of the input device according to the invention, as used to carry out the input method according to the invention; Fig. 2 a detailed view of the input device according to the invention.

[0032] The input device 1 according to the invention, as shown in Fig. 1, is characterized in that it is designed to carry out the input method according to the invention. The input device 1 is at least partially integrated into a steering wheel 10 of a motor vehicle, in particular the spoke of a steering wheel 10 of a motor vehicle. The input device 1 has a scanner 2 and an associated input surface 8. The input surface 8 is part of the surface of the spoke of the steering wheel 10. In the embodiment shown in Fig. 1, the scanner 2 is arranged below the input surface 2. The scanner 2 is aligned so that its detection area, also called scanning area, detects the input surface 8 in such a way that touches of a finger on the input surface 8 can be detected. This contact by the finger (not shown in detail) forms a touch surface 11a, 11b, wherein in the Fig. 1 shows two different contact situations, namely 11a and 11b, as they occur in chronological sequence as a respective snapshot when the finger slides over the input surface 8. The size relationships between the contact surfaces 11a, 11b and the input surface 8 shown are not to scale and are intended for illustrative purposes only. It should be clear to a person skilled in the art that the respective extent of the contact surface 11a or 11b will also vary greatly depending on the contact pressure applied during contact. The scanner 2 is, for example, and not necessarily, a capacitive scanner. The scanner 2 has an array of sensor elements that can be individually evaluated in order to detect the input surface 8 with regard to contact. The scanner 2 is connected to an evaluation unit 3 by means of a line 6.The evaluation unit 3 is hierarchically structured and comprises a primary unit 3a, which is integrated into the spoke of the steering wheel 10, and a secondary unit 3b, which is outside the steering wheel 10 but nevertheless within the . Fig. 1 of a motor vehicle not shown in detail. The primary unit 3a, which is arranged closest to the scanner 2, is connected to the secondary unit 3b via a data communication line 4. The data communication is encrypted and bidirectional as indicated by the arrow 5. For example, the data communication between the primary unit 3a and the secondary unit 3b is designed to initiate a reset of the primary unit 3a, triggered by the secondary unit 3b, if a malfunction of the primary unit 3a is detected by the secondary unit 3b. To monitor the function of the primary unit 3a, in particular of the A / D converter integrated therein for evaluating the first or second data supplied by the scanner 2, a separately generated analog signal 7 with a predetermined level is fed to the latter in order to enable or enable function monitoring of the primary unit 3a based on the associated converted signal.to ensure.

[0033] The input method comprises operating the input device 1 in an identification mode (not explained in detail), which involves detecting a surface structure of the touch surface 11a, 11b of the finger lying in the input area during contact in order to obtain biometric data that serves to identify the user. These methods are generally known, and this identification mode is one of the operating modes of the input device 1 according to the invention. This identification mode is selected selectively, for example, and a substantially stationary touch surface is assumed during operation in the identification mode.

[0034] According to the invention, a first detection mode is further provided, which is described based on the current contact situation, as represented by the contact surfaces 11a and 11b. For this purpose, the input surface 8 has a first sub-area 9a and a second sub-area 9b located outside the first sub-area 9a, each of which is determined by selectively selecting a subset of sensor elements belonging to the array of sensor elements as defined by the scanner 2.

[0035] The first partial area 9a and second partial area 9b each form a contiguous area and are simultaneously recorded multiple times in the respective recording mode, i.e. in the first recording mode and in the second recording mode, over the entire area, i.e. completely encompassing this first 9a and second partial area 9b, and the associated data, i.e. first data and second data, are transmitted to the evaluation unit 3. The aim of the recording modes from the first and second recording mode is to record a movement of the contact surface 11a, 11b in the first partial area 9a and the second partial area 9b, which is spatially separated from the first partial area 9a, from the sequence of recording data (images) from the first and second data.

[0036] The first and second data thus independently obtained are each processed by both the primary unit 3a and the secondary unit 3b of the evaluation unit 3 by means of two different algorithms, for example an absolute or a differential image evaluation method, which are described in Fig. 2 are schematically indicated by the different image patterns in the sub-areas 9a, 9b. In a simple embodiment of the method according to the invention, the first data belonging to the first sub-area are each evaluated by the primary and secondary units using only one of the algorithms. For example, the algorithms are applied in a distributed manner to the primary and secondary units depending on the required computational effort.

[0037] However, an embodiment is conceivable in which the first data and second data are each evaluated by the primary unit 3a as well as the secondary unit 3b using both algorithms in order to achieve a high degree of verification. Only if there is a predetermined minimum agreement between the evaluation results determined by the evaluation unit, for example, within a predetermined time interval, is a switching or control function, such as cursor control, assigned to the detected movement. The goal of detecting the movement of the touch surface 11a, 11b through spatially separated sub-areas, evaluating the data obtained thereby using different algorithms, and using a hierarchically structured evaluation unit consisting of a primary and secondary unit that mutually verify each other, results in a high degree of functional control of the generic input device.According to a preferred embodiment, the aforementioned assignment is additionally verified by the biometric data obtained in the identification mode, ie the assignment only occurs if the biometric data determined in the identification mode have a sufficient match with stored data, in order to thus only make an assignment if the input can be verified by the stored biometric data.

Claims

[1] Input procedure comprising the following steps: Providing an input device (1) comprising an input surface (8) and a scanner (2) which is oriented to detect a touch of a finger on the input surface (8) to form a touch surface (11a, 11b) and an evaluation unit (3) to assign a control and / or switching function to a movement of the touch surface (11a, 11b) on the input surface (8); Operation of the input device (1) in an identification mode in which a surface structure of the touch surface (11a, 11b) of the finger lying in the input surface (8) during the touch is detected by means of the scanner (2) and evaluated by the evaluation unit (3) to generate biometric data; Operation of the input device (1) in a first detection mode, in which a first partial area (9a) of the input surface (8) covered by the touch surface (11a, 11b) is detected several times completely or over its entire area by means of the scanner (2) and associated first data are transmitted to the evaluation unit (3); Operation of the input device (1) in a second detection mode, in which a second partial area (9b) of the input surface (8) covered by the touch surface (11a, 11b) is detected several times completely or over its entire area by means of the scanner (2) and associated second data are transmitted to the evaluation unit (3); Evaluating the first data and second data by the evaluation unit (3) to obtain a first evaluation result and a second evaluation result in order to assign a control and / or switching function to the relative movement of the contact surface (11a, 11b) exclusively if there is a predetermined minimum agreement between the first evaluation result and the second evaluation result characterized by , that the evaluation unit (3) comprises a primary unit (3a) arranged closest to the scanner (2) and evaluating at least the first data, and a secondary unit (3b) connected to the first unit (3a) via a data communication connection, evaluating at least the first data and superordinate to the primary unit (3a), and that the secondary unit (3b) is designed to reset the primary unit if there is no minimum agreement between its evaluation result and the evaluation result of the primary unit (3a). [2] Input method according to the preceding claim, wherein the first partial area (9a) and second partial area (9b) are arranged in a non-overlapping manner. [3] Input method according to one of the preceding claims, using an input area (8) of less than or equal to 2 cm 2 , preferably less than or equal to 1.2 cm 2 , more preferably less than or equal to 0.25 cm 2 . [4] Input method according to the preceding claim, wherein the primary unit (3a) and / or the secondary unit (3b) are function-monitored. [5] Input method according to one of the preceding claims, wherein the scanner (2) defines an array of sensor elements. [6] Input method according to one of the preceding claims, wherein the input device (1) is operated simultaneously in the first detection mode and the second detection mode. [7] Input method according to one of the preceding claims, wherein the evaluation unit (3) evaluates the first and second data according to different algorithms. [8] Input method according to one of the preceding claims, wherein the assignment to a control and / or switching function is additionally verified by the evaluation unit (3) on the basis of the biometric data obtained in the identification mode. [9] Input device (1) for finger navigation, comprising an input surface (8) and a scanner (2) which is aligned and designed to detect a touch of a finger on the input surface (8) to form a touch surface (11a, 11b), and an evaluation unit (3) to assign a control and / or switching function to a movement of the touch surface (11a, 11b) on the input surface (8); wherein the input device (1) is designed to carry out an input method according to one of the preceding claims. [10] Steering wheel (10) for a motor vehicle with an input device (1) according to the preceding claim.

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