ELECTROSTATIC INPUT DEVICE

Abstract

Providing an electrostatic input device capable of activating a capacitance detector in a state prior to contact detection and suppressing false detection. An electrostatic input device comprises: a capacitance detector arranged on an operating part to be actuated by a living body and configured to detect capacitance; and a controller configured to bring the capacitance detector into an activated state in response to an increase in the capacitance detected by the capacitance detector which reaches or exceeds a first predetermined value a predetermined number of times or more within a predetermined time period, in a case where the capacitance detector is in a standby state and no contact with the living body is detected.

Description

TECHNICAL FIELD

[0001] The present invention relates to electrostatic input devices. STATE OF THE ART

[0002] Driving methods for input devices are known that use a capacitance detector provided on an operating part. According to the known driving methods, the capacitance detector is set to a standby state to save energy when there is no contact with the operating part, and the capacitance detector is set to an activated state when there is contact with the operating part (see, for example, Patent Literature 1). CITATION LISTPATENT LITERATURE

[0003] Patent Literature 1: Japanese Patent Application Laid-Open No. 2004-212394 SUMMARY OF THE INVENTION TECHNICAL PROBLEM

[0004] Such existing input device driving methods aim to reach a detection threshold that determines the contact event in a short time. However, they do not necessarily achieve a sufficiently high speed, and there is still room for improvement. One possible countermeasure is to lower the detection threshold that determines the contact event with the operating part. In such a case, however, there is a possibility of an increase in false detections due to activation by, for example, momentary sounds in response to a user's movements.

[0005] In view of the above, it is an object to provide an electrostatic input device capable of activating the capacitance detector in a state before contact is determined and suppressing false detection. SOLUTION TO THE PROBLEM

[0006] An electrostatic input device according to an embodiment of the present invention comprises: a capacitance detector disposed at an operation part to be operated by a living body and configured to detect a capacitance; and a controller configured to switch the capacitance detector to an activated state in response to an increase in the capacitance detected by the capacitance detector reaching or exceeding a first predetermined value a predetermined number of times or more within a predetermined period of time, in which case the capacitance detector is in a standby state and no contact with the living body is detected. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0007] It is possible to provide an electrostatic input device capable of activating the capacitance detector in a state before contact is determined and suppressing false detection. BRIEF DESCRIPTION OF THE DRAWINGS [ Fig. 1] Fig. 1 is a diagram showing a door handle 10 mounted on a vehicle 1. [ Fig. 2] Fig. 2 is a diagram illustrating an electrostatic sensor 110. [ Fig. 3] Fig. 3 is a diagram illustrating an electrostatic input device 100 of an embodiment. [ Fig. 4] Fig. Figure 4 is a diagram illustrating sampling intervals in a normal mode and a power saving mode. [ Fig. 5] Fig. Figure 5 is a diagram illustrating the outputs of sensors 111, 112, and 113. [ Fig. 6] Fig. 6 is a flowchart illustrating a process executed by a controller 126 in power saving mode. [ Fig. 7] Fig. 7 is a flowchart illustrating a process executed by the controller 126 in a first modified example of the embodiment. [ Fig. 8] Fig. 8 is a diagram illustrating the pulse waveforms used for sampling in the normal mode and the power saving mode in a second modified example of the embodiment. [ Fig. 9] Fig. 9 is a flowchart illustrating a process executed by the controller 126 in the second modified example of the embodiment. [ Fig. 10] Fig. 10 is a diagram illustrating the pulse waveforms used for sampling in the normal mode and the power saving mode in a third modified example of the embodiment. [ Fig. 11] Fig. 11 is a flowchart illustrating a process executed by the controller 126 in the third modified example of the embodiment. [ Fig. 12] Fig. 12 is a diagram illustrating the outputs of the sensors 111, 112, and 113 in a fourth modified example of the embodiment. [ Fig. 13] Fig. 13 is a flowchart illustrating a process executed by the controller 126 in the fourth modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Embodiments in which the electrostatic input device of the present invention is applied will be described below. <Ausführungsformen>

[0009] Fig. Figure 1 is a schematic diagram of the door handle 10 mounted on the vehicle 1. The door handle 10 is mounted on a door 2 of the vehicle 1. The door handle 10 has a thin and long shape so that it can be easily grasped with the fingers of a person's hand. The electrostatic sensor 110 is provided inside the door handle 10. Fig. 1 is a longitudinal direction of the door handle 10, a lateral direction in which the door handle 10 extends thin and long.

[0010] Fig. Figure 2 is a diagram showing the electrostatic sensor 110. The electrostatic sensor 110 includes a substrate 110A and sensors 111, 112, and 113. In one example, the sensors 111, 112, and 113 are arranged along the longitudinal direction of the door handle 10. The electrostatic sensor 110 is an example of a capacitance detector.

[0011] Fig. Figure 3 is a diagram illustrating the electrostatic input device 100 of the embodiment. The electrostatic input device 100 includes the electrostatic sensor 110 and an integrated circuit 120.

[0012] The integrated circuit 120 includes a switch 121, a switch 122, an amplifier 123, an ADC (analog-to-digital converter: AD converter) 124, an arithmetic unit 125, and the controller 126. The controller 126 includes a memory 126A contained therein.

[0013] As in Fig. 3, the switch 121 of the integrated circuit 120 is connected to the sensors 111, 112 and 113 of the electrostatic sensor 110.

[0014] Switch 121 is provided between sensors 111, 112, and 113 and an inverted input terminal of amplifier 123. When controller 126 switches a connection destination, the inverted input terminal of amplifier 123 is connected to sensor 111, 112, or 113. A power supply Vdd is connected to a line branching between switch 121 and the inverted input terminal of amplifier 123 via switch 122.

[0015] The switch 122 is provided to sequentially apply a pulse voltage (voltage value: Vdd) to the sensors 111, 112, and 113. This is done by the controller 126, which intermittently turns the switch 122 on and off in a state where the switch 121 is connected to the sensors 111, 112, and 113.

[0016] In this way, when the controller 126 switches the connection destination of the switch 121 and turns the switch 122 on / off, the pulse voltage is applied sequentially to the sensors 111, 112, and 113. Applying the pulse voltage to the sensors 111, 112, and 113 is a sampling of the sensors 111, 112, and 113.

[0017] By scanning sensors 111, 112, and 113 in this way, the potentials detected by sensors 111, 112, and 113 are amplified by amplifier 123 and converted from analog signals to digital signals by ADC 124. Based on the converted digital signals, arithmetic unit 125 can calculate the capacitance between sensors 111, 112, and 113 and a finger 200. The information about the calculated capacitance is stored in memory 126A of controller 126. Controller 126 detects (determines) a user's approach to door handle 10 in accordance with the capacitance information calculated by arithmetic unit 125.

[0018] Fig. Figure 4 is a diagram showing sampling intervals in normal mode and power-saving mode. Normal mode is a mode in which the electrostatic sensor 110 is activated at short time intervals and detects contact with or proximity to the living body. The electrostatic sensor 110 in normal mode is referred to as being in the activated state.

[0019] Power-saving mode is a mode in which the electrostatic sensor 110 is in standby mode. In the standby state, the activation of the electrostatic sensor 110 is limited. For example, by extending the sampling intervals or reducing the number of measurement pulses, the current consumed by the electrostatic sensor 110 and the integrated circuit 120 is set to low. When a predetermined condition is met, the power-saving mode is terminated and the system enters normal mode, and the electrostatic sensor 110 is transferred from the standby state to the activated state.

[0020] In the normal mode, for example, sensors 111, 112, and 113 are sampled at intervals of 5 ms, and a pulse voltage is applied sequentially to sensors 111, 112, and 113 at 5 ms intervals. As in Fig. 4, a single sampling time is a period in which the pulse voltage is applied to each of the sensors 111, 112 and 113 once.

[0021] More specifically, the pulse voltage applied every 5 ms comprises, for example, eight pulses, as shown in the enlarged view on the right. The timing of the pulse voltage applied every 5 ms to sensors 111, 112, and 113 is shifted in time.

[0022] The capacitance calculated by the arithmetic unit 125 in a single sampling operation is an average value of eight capacitances obtained by applying eight pulses, as shown in the enlarged view. This means that the number of measurements in a single sampling operation is eight. For convenience of description, the number of measurements is set to eight here. However, in actual measurement, a larger number of measurements, such as 128 times, 256 times, or the like, may be set to obtain an average value. Conversely, a smaller number of measurements, such as less than eight, such as once or the like, may also be set.

[0023] In power-saving mode, for example, sensors 111, 112, and 113 are sampled at 20 ms intervals, and a pulse voltage is applied sequentially to sensors 111, 112, and 113 at 20 ms intervals. Specifically, the pulse voltage applied every 20 ms comprises eight pulses, as shown in the enlarged view on the right. The timing of the pulse voltage applied every 20 ms to sensors 111, 112, and 113 is shifted in time.

[0024] Similar to the normal mode, a single sampling time is a period of time (period) in which the pulse voltage is applied once to each of the sensors 111, 112, and 113. The capacitance calculated by the arithmetic unit 125 in the single sampling operation is an average value of eight capacitances obtained by applying eight pulses, as shown in the enlarged view.

[0025] In this way, the number of times the pulse voltage is applied to sensors 111, 112, and 113 is reduced in the power-saving mode compared to the normal mode. This also reduces the power consumed by the integrated circuit 120, and the overall power consumed by the electrostatic input device 100 can be reduced.

[0026] In order to activate the electrostatic sensor 110 early from the power saving mode before an approach is detected, one possibility is to lower a threshold at which the controller 126 detects (determines) the user's approach to the door handle 10 according to the outputs of the sensors 111, 112 and 113 and activates the electrostatic sensor 110 at the time of detection.

[0027] However, in the state before the user's hand touches the door handle 10, the outputs of the sensors 111, 112, and 113 may contain noise due to a change in the relative position between the user and the door handle 10, noise, and the like. Even if the controller 126 performs filtering, it is difficult to accurately detect (determine) the user's approach to the door handle 10.

[0028] Fig. Figure 5 is a diagram illustrating the outputs of sensors 111, 112, and 113. Fig. For comparison, Figure 5(A) shows a case in which the user's approach to the door handle 10 is detected (determined) using a single threshold value for the outputs of the sensors 111, 112, and 113. In particular, Fig. 5(A) shows a relationship between the output of the sensor 111, 112 or 113 and the threshold value in this case. Fig. Figure 5(A) is a characteristic diagram schematically illustrating the output of sensor 111, 112, or 113. The average value of the outputs of sensor 111, 112, or 113 has similar characteristics.

[0029] Here, the outputs of sensors 111, 112, and 113 are signals that are input to controller 126. Specifically, signals representing the potentials detected by sensors 111, 112, and 113 are converted into a single signal as an output of switch 121 and amplified by amplifier 123. Subsequently, the signal is converted into a digital signal by ADC 124, and the capacitance is determined by arithmetic unit 125. That is, the outputs of sensors 111, 112, and 113 are signals representing the capacitance, which are input to controller 126.

[0030] As in Fig. As shown in Figure 5(A), when the controller 126 detects (determines) a user's approach to the door handle 10 according to the outputs of the sensors 111, 112, and 113 and uses a single low threshold set to detect the user's approach to the door handle 10, the threshold is exceeded as a result of a single large capacitance change due to the influence of noise, unintentional movements of the user, or the like. This may be detected as a user's approach to the door handle 10 and may result in false detection.

[0031] In addition, when the threshold value is increased to avoid false detections, there is a possibility that the electrostatic sensor 110 may not be able to be activated at a time convenient enough for the user to not feel a delay in response when the user approaches the door handle 10.

[0032] In view of this, according to the electrostatic input device 100 of the embodiment, the electrostatic sensor 110 is activated in response to the increase in the capacitance detected by the electrostatic sensor 110 reaching or exceeding a predetermined value Ca (an example of the first predetermined value) the predetermined number of times or more within the predetermined period of time.

[0033] Fig. 5(B) is an example showing a waveform obtained by sampling with the Fig. 4 in normal mode or in power-saving mode, and illustrates fluctuations in the capacitances measured by sensors 111, 112, and 113 in three sampling operations. The capacitance measured by sensors 111, 112, or 113 in each of the sampling operations indicates an average value of the eight capacitances obtained by applying the eight pulses as described above. The leftmost capacitance data in this graph is the final sampling result. For simplicity, here, the capacitances measured by sensors 111, 112, and 113 are simply treated as the same value, i.e., C0, assuming a state in which the user does not approach the door handle 10 (non-operational state).

[0034] In each of the sampling operations, three capacitances are measured by the three sensors 111, 112, and 113. In the following description, the increment in capacitance ΔC1, ΔC2, or ΔC3 obtained from the sensor 111, 112, or 113 in each of the first to third sampling operations is calculated by subtracting from the maximum value of the capacitances measured in the current sampling operation by the sensors 111, 112, and 113 the capacitance measured in the previous sampling operation by the sensor (111, 112, or 113) from which the maximum value of the capacitances was obtained.

[0035] For example, to calculate the increase in capacitance, the maximum value of the increase in capacitance for each of the sensors between samplings can be used as a representative value for the increase between those samplings. Alternatively, the increase between samplings can be calculated using an average or total value of the capacitances measured by the sensors in each of the samplings. Alternatively, the maximum value of the capacitances measured by the sensors in each sampling can be treated as a representative value in that sampling, and the increase between samplings can be calculated using this representative value. Alternatively, an average or total value of the increases by the sensors between samplings can also be used as the increases between those samplings.A calculation method for the increase or representative value of the capacitances in the sampling operations can be appropriately determined in accordance with a system used.

[0036] For example, it is assumed that the capacitance measured by sensor 111 is the maximum in the first sampling operation, the capacitance measured by sensor 112 is the maximum in the second sampling operation, and the capacitance measured by sensor 113 is the maximum in the third sampling operation. This is assumed, for example, in a case where a person's hand, finger, or the like approaches sensor 113 obliquely from above sensor 111.

[0037] In this case, ΔC1 is the value obtained by subtracting the capacitance C0 of the last sampling (non-operating state) from the capacitance measured by sensor 111, which represents the maximum value in the first sampling. ΔC2 is also a value obtained by subtracting the capacitance measured by sensor 112 in the first sampling from the capacitance measured by sensor 112, which represents the maximum value in the second sampling. Similarly, ΔC3 is a value obtained by subtracting the capacitance measured by sensor 112 in the second sampling from the capacitance measured by sensor 113, which represents the maximum value in the third sampling.

[0038] As in Fig. As shown in Figure 5(B), when the capacitance detected by the electrostatic sensor 110 increases threefold or more within a period TP1, and ΔC1, ΔC2, and ΔC3 are each a predetermined value of Ca or more in the three or more samplings of the capacitance increase, the power saving mode is transitioned to the normal mode, thereby activating the electrostatic sensor 110. At this time, ΔC1 > Ca, ΔC2 > Ca, and ΔC3 > Ca.

[0039] That is, in the example shown in Fig. As shown in Figure 5(B), the predetermined time period is the period (period) TP1, the predetermined number of times is three, and the capacitance increments used for determination are ΔC1, ΔC2, and ΔC3. To simplify the description, an example will be described in which the capacitance increments reach or exceed the predetermined value Ca in consecutive sampling operations. However, between the sampling operations described above, a sampling operation in which the increment does not exceed the predetermined value Ca or in which the capacitance decreases may also be included. The sampling operations in which the increments reach or exceed the predetermined value Ca may not be consecutive as long as the sampling operations in which the increments reach or exceed the predetermined value Ca within the predetermined time period exist a predetermined number of times or more. Fig. 5(B), the period TP1 is shown as a period of time approximately corresponding to the period of time in which the three sampling operations are performed. However, the predetermined period of time may be set to a longer period of time as long as the set period of time allows sampling operations to be performed more than the predetermined number of times. Fig. The example shown in Figure 5(B) illustrates a case where the counting of the period TP1 is started from the starting point of the first sampling operation in which the increase in capacity exceeds the value Ca. However, after the completion of the period TP1, the counting of the period TP1 can be restarted if the increase in capacity exceeds Ca again. As an example, at the time point at which the increase in capacity exceeds Ca again before the counting of the period TP1 started in the first sampling operation is completed (e.g., the second or third sampling operation in Fig. 5(B)), the following settings are possible: that is, counting of the predetermined period may be started from the time point serving as the starting point, counting of the predetermined period may be performed in parallel with counting the period TP1 started in the first sampling operation, and the number of approaches may be counted for each of the predetermined periods. At this time, when the number of approaches reaches or exceeds the predetermined number during counting of any of the predetermined periods, the power saving mode is switched to the normal mode. In addition, for example, the starting point of the period TP1 may also be the time at which a parameter other than the increase in capacity exceeds a predetermined value. The period TP1 may also be set to be counted at predetermined time intervals, regardless of the predetermined value.

[0040] The controller 126 includes a proximity event counter configured to count the number of proximity events. The proximity event counter is an example of such a counter. If the capacitance detected by the electrostatic sensor 110 in the current scan increases by a value greater than or equal to the predetermined value Ca compared to the capacitance detected in the previous scan, the controller 126 increments the proximity event counter. If the proximity event counter reaches three or more within a predetermined period of time (the period TP1), the controller 126 activates the electrostatic sensor 110.

[0041] Hereinafter, the fulfillment of the following condition is referred to as fulfillment of an activation condition: in the power-saving mode, the capacitance increases ΔC1, ΔC2, and ΔC3 detected by the electrostatic sensor 110 reach or exceed the predetermined value Ca three times or more within the time period TP1. When the activation condition is met, the controller 126 activates the electrostatic sensor 110.

[0042] According to the electrostatic input device 100 of the embodiment, the user's approach to the door handle 10 is detected (determined) when the electrostatic sensor 110 is in the standby state, wherein the Fig. The determination method shown in Figure 5(B) is used.

[0043] In a case where the activation condition is met and the electrostatic sensor 110 is activated, when the controller 126 determines that the output of the sensor 111, 112 or 113 in normal mode exceeds the threshold value that determines contact with the vehicle 1 (see Fig. 1), the controller 126 detects contact with the door handle and transmits a signal allowing unlocking of a door lock to an ECU (Electronic Control Unit) configured to control the door lock of the vehicle 1. As a result, the door lock is unlocked.

[0044] Fig. Figure 6 is a flowchart illustrating a process executed by the controller 126 in the power saving mode. The controller 126 executes the Fig. 6 repeatedly executes the flow chart shown in a predetermined control cycle corresponding to Fig. 4. The capacitance calculated by the arithmetic unit 125 is converted from an analog value to a digital value, and, for example, 10 pF becomes a counter reading as a digital value.

[0045] When the process is started, the controller 126 performs scanning of the sensors 111, 112 and 113 by controlling the connection of the switches 121 and 122 in the power saving mode (step S1).

[0046] The controller 126 determines whether or not the capacitance calculated by the arithmetic unit 125 is equal to or greater than a predetermined value Cwake, which allows transition to the normal mode (step S2). The capacitance calculated at this time indicates the average value of the eight capacitances obtained by applying the eight pulses as described above. Furthermore, the predetermined value Cwake is set to a capacitance value large enough to accurately detect an increase in capacitance caused by the user approaching the door handle 10 by determining it once using a single threshold value, without causing false detection.

[0047] If the controller 126 determines that the calculated capacity is equal to or greater than the predetermined value Cwake (S2: YES), transition to the normal mode is performed (step S3). As an example, a configuration will be described here in which a condition for transitioning to step S3 is equal to or greater than the predetermined value Cwake, which represents the user's approach to the door handle 10. However, if it can be reliably determined that the user has approached the sensors 111, 112, and 113, such a condition can be used as a condition for transitioning to the normal mode.

[0048] The controller 126 clears the proximity event counter stored in a memory to 0 (step S4).

[0049] When the controller 126 ends the process of step S4, the controller 126 ends the process in the control cycle corresponding to the current sampling time (END).

[0050] When the controller 126 determines in step S2 that the calculated capacitance does not correspond to the predetermined value Cwake or more (S2: NO), the controller 126 determines whether or not the increase in the capacitance obtained in the previous sampling operation corresponds to the predetermined value Ca or more (step S5).

[0051] The determination in step S5 is an operation which corresponds to the Fig. 5(B), that is, a process that determines whether or not the maximum value of the three capacitances obtained from the sensors 111, 112, and 113 in the current sampling operation has increased by the predetermined value Ca or more from the capacitance of the corresponding sensor (111, 112, or 113) in the previous sampling operation.

[0052] When the controller 126 determines that the increase has increased by the predetermined value Ca or more (S5: YES), the controller 126 increments the proximity event counter, that is, adds one to the count value stored in the memory, followed by overwriting (step S6).

[0053] The controller 126 determines whether or not the proximity event counter is three or more (step S7).

[0054] When the controller 126 determines that the proximity event counter is three or more (S7: YES), the controller 126 causes the process to proceed to step S3 to perform the transition to the normal mode.

[0055] When the controller 126 determines in step S5 that the increment has not increased by the predetermined value Ca or more (S5: NO), the controller 126 determines whether or not the time from the start of counting, ie, the time period, is equal to or longer than the period TP1 (step S8).

[0056] If the controller 126 determines that the time period is equal to or longer than the time period TP1 (S8: YES), the controller 126 clears the proximity event counter stored in the memory to 0 (step S9).

[0057] If the controller 126 determines in step S7 that the proximity event counter is not three or more (S7: NO), the controller 126 ends the process in the current control cycle (END). Then, the controller 126 repeats the process from step S1 in a control cycle corresponding to the next sampling time.

[0058] If the controller 126 determines in step S8 that the time period is not equal to or longer than the period TP1 (S8: NO), the controller 126 ends the process in the control cycle corresponding to the current sampling time point (END).

[0059] In the method described above, the transition to the normal mode occurs when the capacitance detected by the electrostatic sensor 110 increases as a result of the user approaching the door handle 10 in the power saving mode and the increase in the capacitance from the capacitance in the previous sensing operation reaches or exceeds the predetermined value Ca three times or more within the time period TP1.

[0060] Therefore, it is possible to suppress false detection due to noise, unintentional user movements, or the like, and to quickly transition the power-saving mode to the normal mode when the user's hand, fingers, or the like approach the electrostatic sensor.

[0061] Accordingly, it is possible to provide the electrostatic sensor 110 which is quickly activated from the standby state and is suppressed upon false detection.

[0062] In the above, a configuration was described in which the electrostatic sensor 110 comprises the three sensors 111, 112, and 113. The number of sensors can be two, or four or more. In these cases, a control method performed by the controller 126 is the same as that in which the electrostatic sensor 110 comprises the three sensors 111, 112, and 113.

[0063] The electrostatic sensor 110 may comprise a single sensor (for example, sensor 111). In this case, if the capacitance detected by sensor 111 reaches or exceeds the predetermined value Ca within the time period TP1 compared to the capacitance in the previous sampling operation three times or more, the power-saving mode may transition to the normal mode.

[0064] In step S5, the proximity event counter is incremented when the capacitance value increases by the predetermined value Ca or more from the time of the previous sampling operation. However, the proximity event counter may also be incremented when the capacitance value increases over time. As shown in Fig. As shown in Figure 5(B), the capacitance increment obtained in the first sampling operation within the period TP1 is denoted by ΔC1, the capacitance increment obtained in the second sampling operation within the period TP1 is denoted by ΔC2, and the capacitance increment obtained in the third sampling operation within the period TP1 is denoted by ΔC3. In step S5, if ΔC1 is the predetermined value Ca or more in the first sampling operation, the relationship ΔC1 < ΔC2 is satisfied in the second sampling operation, or the relationship ΔC2 < ΔC3 is satisfied in the third sampling operation, the proximity event counter may be incremented. In this case, a sampling operation in which the increment does not exceed the predetermined value Ca or the capacitance decreases during the period TP1 may be included. One possible method for confirming this is as follows. Specifically, the capacitance values ​​in the sampling operations are stored in the memory.The increments in the sampling operations that are the predetermined values ​​Ca or more are denoted by ΔC1, ΔC2, and ΔC3. The relationship of ΔC1 < ΔC2 < ΔC3 is determined within the period TP1. If the relationship is satisfied, the transition to normal mode is performed. The same applies to the subsequent ΔC1, ΔC2, and ΔC3.

[0065] In the above description, a case was described where the increment increases in the first, second, and third sampling operations. However, the predetermined value for comparison can be increased and compared step by step. Specifically, when Ca < ΔC1, Cb < ΔC2, Cc < ΔC3, and Ca < Cb < Cc are satisfied, the transition to normal mode can be performed.

[0066] In addition, a threshold may be provided for the difference between the capacity increases obtained within the period TP1. In particular, as in Fig. As shown in Figure 5(B), when the capacity increments ΔC1, ΔC2, and ΔC3 obtained three times within the time period TP1 each increase by the predetermined value Ca or more over time, the transition to the normal mode is performed. This means that ΔC2 - ΔC1 ​​> Ca and ΔC3 - ΔC2 > Ca are satisfied.

[0067] Even if the difference between the capacity increases is Ca or more and increases with time so that a relationship of ΔC3 - ΔC2 > ΔC2 - ΔC1 ​​> Ca is satisfied, the transition to the normal mode can be performed.

[0068] In other words, when the difference between the capacity increases increases with time and increases gradually from Ca to Cb (> Ca) so that relationships ΔC2 - ΔC1 ​​> Ca, ΔC3 - ΔC2 > Cb and Cb > Ca are satisfied, the transition to the normal mode can be performed.

[0069] With regard to step S8, a configuration was described in which the proximity event counter is cleared after the elapse of the period TP1. However, if a very large increment is obtained, for example, if an increment from the capacitance obtained in the previous sampling operation is two or more times greater than the predetermined value Ca, even if the value obtained in the current sampling operation is smaller than the predetermined value and the time period TP1 has passed, the count value cannot be decremented or changed to one without clearing the proximity event counter. The reason for this is that, in view of the individually different ways of approaching the vehicle 1, a faster transition to the normal mode (activation of the electrostatic sensor 110) is possible at the next determination.The value that is twice greater than the predetermined value Ca is an example of a third predetermined value. The decremented count value "1" or the unchanged count value is an example of a second predetermined count value.

[0070] Fig. Fig. 7 is a flowchart illustrating a process executed by the controller 126 in the first modified example of the embodiment. Fig. The flowchart shown in Figure 7 is the same as the one in Fig. 6, except that a transition process from the normal mode to the power saving mode has been added, ie, a process with steps S11 to S15. Therefore, only the difference from Fig. 6 described.

[0071] When the process is started, the controller 126 determines whether the power saving mode is set or not (step S11).

[0072] If the controller 126 determines that the power saving mode is not set (step S11: NO), the controller 126 performs a scanning operation in the normal mode (step S12). That is, as shown in Fig. As shown in Figure 4, sampling is performed in 5 ms cycles.

[0073] The controller 126 determines whether the condition for transitioning to the power-saving mode is met (step S13). The condition for transitioning to the power-saving mode is that the capacitance detected by the sensors 111, 112, and 113 in the last 30 seconds is equal to or less than a predetermined value, which indicates that there is no contact with the door handle 10. The 30 seconds is an example of a predetermined time included in the condition for transitioning to the power-saving mode.

[0074] If the controller 126 determines that the condition for transitioning to the power saving mode is met (S13: YES), the controller 126 performs the transition to the power saving mode (step S14).

[0075] The controller 126 clears the proximity event counter (step S15). When the controller 126 completes the process of step S15, the controller 126 ends the process (END).

[0076] If the controller 126 determines in step S13 that the condition for transitioning to the power saving mode is not met (S13: NO), the controller 126 ends the process (END).

[0077] If the controller 126 determines in step S11 that the power saving mode is set (S11: YES), the controller 126 causes the flow to proceed to step S1. Thereafter, the process proceeds in the same manner as shown in the flowchart in Fig. 6 shown.

[0078] In a manner in which setting to the power saving mode is first determined, as in Fig. 7, when the controller 126 determines that the power saving mode is not set (S11: NO), scanning is performed in the normal mode.

[0079] Fig. 8 is a diagram illustrating the pulse waveforms used for sampling in the normal mode and the power saving mode in the second modified example of the embodiment.

[0080] In normal mode, similar to Fig. 4, sensors 111, 112, and 113 are sampled at intervals of 5 ms, as an example. The pulse voltage applied every 5 ms comprises, for example, eight pulses, as shown in the enlarged view on the right. The capacitance calculated by the arithmetic unit 125 in a single sampling operation is an average value of the eight capacitances obtained by applying the eight pulses, as shown in the enlarged view.

[0081] Meanwhile, in power-saving mode, sensors 111, 112, and 113 are sampled at 20 ms intervals, for example. However, the pulse voltage applied every 20 ms comprises, for example, four pulses, as shown in the enlarged view on the right. The capacitance calculated by the arithmetic unit 125 in a single sampling operation is an average value of the four capacitances obtained by applying the four pulses, as shown in the enlarged view. Therefore, the number of measurements in one sampling operation is four.

[0082] In this way, by reducing the number of measurements in the single sampling process, the energy consumed in power saving mode can be further reduced.

[0083] Fig. 9 is a flowchart illustrating a process executed by the controller 126 in the second modified example of the embodiment. Fig. The flowchart shown in Figure 9 is the same as the one in Fig. 7, except that the processes in steps S3 and S14 have been changed. Therefore, only the difference to Fig. 7 described.

[0084] If the controller 126 determines that the condition for transitioning to the power saving mode is met (S13: YES), the controller 126 executes the transition to the power saving mode (step S14A). In step S14A, as shown in the enlarged view of the power saving mode in Fig. 8, the number of measurements in the single scanning process is reduced to four.

[0085] If the controller 126 determines in step S2 that the capacitance is the predetermined value Cwake or more (S2: YES), the controller 126 transitions to the normal mode (step S3A). In step S3A, the number of measurements in the single sampling operation in the normal mode is changed to eight.

[0086] As described above, in power-saving mode, the number of measurements per scan can be reduced compared to normal mode. Although the method for reducing the number of measurements to four has been described here, the number of measurements can be arbitrary, as long as it is less than the number of measurements in normal mode.

[0087] Fig. 10 is a diagram illustrating the pulse waveforms used for sampling in the normal mode and the power saving mode in the third modified example of the embodiment.

[0088] In power-saving mode, the capacitance is measured in a state where the user is approaching the door handle 10. Therefore, the measurement may be affected by noise and the like. In such a case, the frequency at which the pulses used to perform multiple measurements in a single sampling operation are output can be changed to a frequency less affected by noise. In this case, so-called frequency hopping is used to change the frequency.

[0089] To select a frequency that is less affected by noise, it is necessary to detect a frequency that is less affected by noise. The degree of noise can be estimated by continuously measuring capacitances of the same frequency in a very short cycle and observing the difference between them. According to the third modified example shown in the enlarged view of Fig. As shown in Figure 10, in normal mode, eight pulses are output for measurement (solid line), followed by changing the frequency and outputting six pulses (dashed line) to detect the frequency less affected by noise. Here, measuring capacitance with the dashed pulses is referred to as noise sampling.

[0090] When such noise sampling is performed, the frequency is less affected by noise because the capacity calculated by the arithmetic unit 125 is smaller. The dashed six pulses are those of three different frequencies, and two pulses of the same frequency are output sequentially.

[0091] The measurement is performed with six pulses for noise sampling, and the frequency of the pulse at which the capacitance is lowest can be set to the frequency of the eight pulses for measurement in the next sampling.

[0092] When using this type of frequency hopping, in power-saving mode, eight pulses (shown as a solid line) are output for measurement, followed by a frequency change, and four pulses (shown as a dashed line) are output for noise sampling. This means that the number of dashed pulses for noise sampling is two fewer than in normal mode.

[0093] In energy-saving mode, power consumption can be reduced by reducing the number of pulses for noise sampling. The number of values ​​for the frequency and the number of pulses, as in Fig. 10 are examples and can be changed accordingly.

[0094] Fig. 11 is a flowchart illustrating a process executed by the controller 126 in the third modified example of the embodiment. Fig. 11 is the same as the flowchart shown in Fig. 9, except that step S21 has been added and the processes of steps S3 and S14 have been changed. Therefore, only the difference from Fig. 9 described.

[0095] When the process starts, the controller 126 sets the pulse frequency for measuring the noise sampling result (step S21). When the process of step S21 is performed for the first time, the noise sampling result is not available, and therefore the pulse frequency for noise sampling can be set to a predetermined initial value. When the controller 126 terminates the process of step S21, the controller 126 causes the process to proceed to step S11.

[0096] In step S14B, the controller 126 reduces the number of pulses for noise sampling to four when transitioning to the power saving mode (step S14B).

[0097] In step S3B, the controller 126 increases the number of pulses for noise sampling to six when transitioning to the normal mode (step S3B).

[0098] As described above, when performing noise sampling using frequency hopping, power consumption can be reduced by reducing the number of pulses for noise sampling in power saving mode.

[0099] Fig. Fig. 12 is a diagram showing outputs of the sensors 111, 112, and 113 in the fourth modified example of the embodiment. In the fourth modified example, as shown in Fig. As shown in Figure 5(B), when the capacity increments ΔC1, ΔC2, and ΔC3 increase by the predetermined value Ca or more three times or more over time, the cumulative value of the differences between the increments is used to determine whether or not to perform a transition instead of performing the transition to the normal mode.

[0100] As in Fig. As shown in Figure 12, when sensors 111, 112, and 113 are sampled four times, it is assumed that the capacitance increments obtained by sensors 111, 112, and 113 in the first sampling operation are ΔC11, ΔC12, and ΔC13. Similarly, it is assumed that the capacitance increments obtained by sensors 111, 112, and 113 in the second sampling operation are ΔC21, ΔC22, and ΔC23, and the capacitance increments obtained by sensors 111, 112, and 113 in the third sampling operation are ΔC31, ΔC32, and ΔC33. It is also assumed that the capacitance increments obtained from sensors 111, 112, and 113 in the fourth sampling operation are ΔC41, ΔC42, and ΔC43.

[0101] In this case, when the cumulative value of the differences between: the capacity increases obtained over time within the predetermined period (period TP1) and the capacity increases in the corresponding previous sampling operations reaches or exceeds the predetermined value Cb the predetermined number of times or more, the transition to the normal mode is performed. Fig. 5(B), the time period TP1 is started from the starting point, that is, from the sampling operation in which the capacity increase exceeds Ca. In the fourth modified example of the present embodiment, as an example, a sampling operation in which the capacity increase exceeds a predetermined value is the starting point (in Fig. 12 (assuming that the capacitance increase exceeds the predetermined value in the first sampling operation). However, this is by no means a limitation. The starting point of the period TP1 may be the time at which the cumulative value of the differences between the increases exceeds the predetermined value, or the time at which the capacitance exceeds the predetermined value. In addition to the time at which the capacitance increase or the cumulative value of the differences between the increases exceeds the predetermined value as described above, the starting point of the period TP1 may also be set at predetermined time intervals.

[0102] The cumulative value used in the present invention may be a cumulative value of target numerical values ​​(differences between capacitance increases in the fourth modified example of the above-described embodiment) during the previously set sampling period or at the previously set number of samplings. Furthermore, the sampling period or the number of samplings for accumulation is set to an appropriate period or number of times according to the detection level of the capacitance, the sampling conditions, and the like. For example, the sampling period in which the cumulative value is obtained may be equal to or shorter than the above-determined period (period TP1). The cumulative value obtained by accumulation starting from a period before the above-determined period (period TP1) may also be set.The cumulative value is cleared at the end of the cumulative sampling period or after the number of cumulative samplings.

[0103] When the electrostatic sensor 110 includes the sensors 111, 112, and 113, the difference of the capacitance increments in the previous scanning operation can be obtained as a difference between an average value of the capacitance increments in the previous scanning operation and an average value of the capacitance increments in the current scanning operation.

[0104] The cumulative value is determined as follows. For example, if four sampling operations are performed, a difference Cα1 is determined by subtracting the average value of the increments ΔC11, ΔC12, and ΔC13 obtained in the first sampling operation from the average value of the increments ΔC21, ΔC22, and ΔC23 obtained in the second sampling operation.

[0105] Similarly, a difference Cα2 is determined by subtracting the average value of the increments ΔC21, ΔC22 and ΔC23 obtained in the second sampling from the average value of the increments ΔC31, ΔC32 and ΔC33 obtained in the third sampling.

[0106] Similarly, a difference Cα3 is determined by subtracting the average value of the increments ΔC31, ΔC32 and ΔC33 obtained in the third sampling from the average value of the increments ΔC41, ΔC42 and ΔC43 obtained in the fourth sampling.

[0107] Then, the cumulative value (total value) of the differences Cα1, Cα2, and Cα3 is determined. If this cumulative value is equal to or greater than the predetermined value Cb (an example of the second predetermined value), the transition to normal mode is performed. The predetermined value here is a value indicating how close the user has approached the door handle 10.

[0108] Instead of the average value of the increments determined in each sampling process, the maximum value or the total value of the increments determined in each sampling process by the three sensors can also be used. A calculation method for the increments or the representative value of the capacitances in the sampling processes can be determined in a suitable manner in accordance with an applied system.

[0109] Fig. 13 is a flowchart illustrating a process executed by the controller 126 in the fourth modified example of the embodiment. Fig. 13 is the same as the flowchart shown in Fig. 9, except that the processes of steps S5 and S8 have been changed. Therefore, only the difference to Fig. 9 described.

[0110] In step S5A, the controller 126 determines whether or not the cumulative value of the differences between the average value of the capacity increase obtained in the previous sampling operation and the average value of the capacity increase obtained in the current sampling operation is the predetermined value Cb or more (step S5A).

[0111] In step S8A, when the controller 126 determines in step S5A that the cumulative value is not the predetermined value Cb or more (S5A: NO), the controller 126 determines whether or not the time period is the time period TP1 or longer (step S8A).

[0112] In the Fig.13, the sampling process is repeated in step S1. As a result, if the cumulative value of the differences reaches or exceeds the predetermined value Cb three or more times within the time period TP1, it is determined to be YES in step S7, and then, in step S3, the transition to the normal mode is performed, thereby activating the electrostatic sensor 110. The number of times based on which it is determined to be YES in step S7 can be set appropriately. For example, the electrostatic sensor 110 can be activated even if the cumulative value reaches or exceeds the predetermined value Cb only once.

[0113] In the configuration described above, the cumulative value of the differences in the capacitance increments from the capacitance increments obtained in the previous sampling process is used. However, the same process can also be performed using the capacitance increments rather than the differences between them. For example, when the cumulative value of the capacitance increments ΔC1, ΔC2, and ΔC3 reaches or exceeds the predetermined value Cb the predetermined number of times, the transition to the normal mode is performed. At this time, the predetermined value Cb for the cumulative value can be set to increase gradually.

[0114] At this time, only the capacity increments ΔC1, ΔC2 and ΔC3 corresponding to the predetermined value Ca or more can be used, and when their cumulative value reaches or exceeds the predetermined value Cb, the transition to the normal mode can be performed.

[0115] Alternatively, when the capacity increase ΔC1 is the predetermined value Ca or more and a relationship of ΔC1 < ΔC2 < ΔC3 is satisfied, the cumulative value of ΔC1, ΔC2 and ΔC3 may be calculated and used for determination.

[0116] In this case, when the relationships Ca < ΔC1, Cb < ΔC2 and Cc < ΔC3 and a relationship Ca < Cb < Cc are satisfied, the cumulative value of ΔC1, ΔC2 and ΔC3 can be calculated and used for determination.

[0117] Although the electrostatic input device of the illustrative embodiment of the present invention has been described above, the present invention may be any combination of the specifically disclosed embodiments.

[0118] The present invention is not limited to the specifically disclosed embodiments and may be changed and modified in various ways without departing from the appended claims.

[0119] The present international application claims priority from Japanese patent application No. 2022-000281, filed on 4 January 2022, the entire contents of which are incorporated by reference into the present international application. REFERENCE SYMBOL LIST 10 door handle 100 Electrostatic input device 110,110M Electrostatic Sensor 111,112,113,111M,112M Sensor 120 Integrated Circuit 126 controllers QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2004-212394

[0003] JP 2022-000281

[0119]

Claims

[1] An electrostatic input device comprising: a capacitance detector arranged on an operating part to be operated by a living body and configured to detect capacitance; and a controller configured to place the capacitance detector into an activated state in response to an increase in the capacitance detected by the capacitance detector reaching or exceeding a first predetermined value a predetermined number of times or more within a predetermined period of time in a case where the capacitance detector is in a standby state and no contact with the living body is detected. [2] The electrostatic input device according to claim 1, wherein the controller comprises a counter configured to increment a value in response to the increase in capacity reaching or exceeding the first predetermined value, and the controller is configured to transition the capacitance detector to the activated state in response to a count of the counter reaching a predetermined count within the predetermined period of time, the predetermined count corresponding to the predetermined number of times. [3] The electrostatic input device of claim 1, wherein the controller is configured to transition the capacitance detector to the activated state in response to an increase in the increase in capacitance over time reaching or exceeding the first predetermined value. [4] The electrostatic input device according to claim 1, wherein the controller is configured to gradually increase the first predetermined value within the predetermined period of time. [5] An electrostatic input device comprising: a capacitance detector arranged on an operating part to be operated by a living body and configured to detect capacitance; and a controller configured to transition the capacitance detector to an activated state in response to a cumulative value of increases in the capacitance detected by the capacitance detector reaching or exceeding a second predetermined value a predetermined number of times or more within a predetermined period of time in a case where the capacitance detector is in a standby state and no contact with the living body is detected. [6] The electrostatic input device according to claim 5, wherein the controller comprises a counter configured to increase a value in response to the cumulative value of the increases in capacity reaching or exceeding the second predetermined value, and the controller is configured to transition the capacitance detector to the activated state in response to a count of the counter reaching a predetermined count within the predetermined period of time, the predetermined count corresponding to the predetermined number of times. [7] The electrostatic input device according to claim 5, wherein the controller is configured to gradually increase the second predetermined value within the predetermined period of time. [8] The electrostatic input device according to claim 5, wherein the controller is configured to transition the capacitance detector to the activated state in response to the cumulative value of the increases in capacitance reaching or exceeding a first predetermined value reaching or exceeding the second predetermined value the predetermined number of times or more within the predetermined period of time. [9] The electrostatic input device of claim 5, wherein the controller is configured to transition the capacitance detector to the activated state in response to increases in capacitance reaching or exceeding a first predetermined value that increases over time and a cumulative value of the increased increases in capacitance reaching or exceeding the second predetermined value. [10] The electrostatic input device according to claim 8, wherein the controller is configured to gradually increase the first predetermined value within the predetermined period of time. [11] An electrostatic input device comprising: a capacitance detector arranged on an operation part to be operated by a living body and configured to detect a capacitance; and a controller configured to place the capacitance detector into an activated state in response to a difference between increments in capacitance successively detected by the capacitance detector reaching or exceeding a first predetermined value a predetermined number of times or more within a predetermined period of time in a case where the capacitance detector is in a standby state and no contact with the living body is detected. [12] The electrostatic input device according to claim 11, wherein the controller comprises a counter configured to increase a value in response to the difference reaching or exceeding the first predetermined value, and the controller is configured to transition the capacitance detector to the activated state in response to a count of the counter reaching a predetermined count within the predetermined period of time, the predetermined count corresponding to the predetermined number of times. [13] The electrostatic input device of claim 11, wherein the controller is configured to transition the capacitance detector to the activated state in response to the difference reaching or exceeding the first predetermined value in association with the difference reaching or exceeding the first predetermined value increasing over time. [14] The electrostatic input device according to claim 11, wherein the controller is configured to gradually increase the first predetermined value within the predetermined period of time. [15] An electrostatic input device comprising: a capacitance detector arranged on an operating part to be operated by a living body and configured to detect capacitance; and a controller configured to transition the capacitance detector to an activated state in response to a cumulative value of differences between increments in capacitance successively detected by the capacitance detector reaching or exceeding a second predetermined value a predetermined number of times or more within a predetermined period of time, in a case where the capacitance detector is in a standby state and no contact with the living body is detected. [16] The electrostatic input device according to claim 15, wherein the controller comprises a counter configured to increase a value in response to the cumulative value of the differences reaching or exceeding the second predetermined value, and the controller is configured to transition the capacitance detector to the activated state in response to a count of the counter reaching a predetermined count within the predetermined period of time, the predetermined count corresponding to the predetermined number of times. [17] The electrostatic input device according to any one of claims 2, 6, 12 and 16, wherein the controller is configured to clear the count value of the counter in response to the count value of the counter not reaching the predetermined count value within the predetermined period of time. [18] The electrostatic input device according to claim 2 or 12, wherein in response to the count value of the counter not reaching the predetermined count value within the predetermined period of time, the controller is configured to clear the count value of the counter in response to the increase in capacity reaching or falling below a third predetermined value which is greater than the first predetermined value, or to set a second predetermined value which is less than the predetermined count value without clearing the count value in response to the increase in capacity reaching or exceeding the third predetermined value. [19] The electrostatic input device according to any one of claims 1 to 18, further comprising: the operation part. [20] The electrostatic input device according to any one of claims 1 to 19, wherein the controller is configured to to put the capacitance detector into standby mode without the living body touching the operation part, and to set the capacitance detector so that it is in the activated state when the living body touches the operating part. [21] The electrostatic input device according to any one of claims 1 to 20, wherein the capacitance detector comprises several sensors, and the controller is configured to transfer the capacitance detector to the activated state, wherein as the capacitance a maximum value, an average value or a total value of a plurality of capacitances is used which are detected by the plurality of sensors the predetermined number of times or more within the predetermined period of time.

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