JP2015130122A - Capacitive operation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce false determination and improve operability.SOLUTION: A capacitive operation device includes an operation plate with an operation surface which is touch-operated by a fingertip F, and an electrode, as well as detection means, sudden-change determination means, and touch determination means. The detection means acquires a detection value according to the amount of change in capacitance which is generated between the fingertip and the electrode. The sudden-change determination means determines whether a sudden-change phenomenon has appeared in change periods Tup, Tdw of the detection value, where the amount of change V2-V1, V3-V4 in change speed per unit time is equal to or larger than a predetermined amount ΔVth. The touch determination means determines a touch operation or a separation operation on the condition that the sudden-change phenomenon is determined.

Description

  The present invention relates to a capacitive operation device that is operated by contact with an operating body (for example, a user's fingertip).

  Patent Document 1 discloses a capacitance type operation device that includes an operation plate that forms an operation surface that is touched by a user's fingertip, and an electrode that is disposed on the back side of the operation plate. This operation device acquires a detection value corresponding to the amount of change in capacitance generated between the electrode and the fingertip, and when the acquired detection value exceeds a predetermined threshold value, a contact operation is performed. And turn on.

  Now, when the fingertip is lightly touched on the operation surface, the contact area between the fingertip and the operation surface is smaller than when the fingertip is strongly pressed against the operation surface, so the detection value is small. Therefore, if the threshold value is set low, an ON determination can be made simply by lightly touching the operation surface, thereby improving operability.

  On the other hand, if the operator's fingertip is large or the fingertip is wet with sweat, the detection value will appear large.If the threshold value is lowered as described above, it will be turned on only by bringing the fingertip close without touching the operation surface. An erroneous determination such as being determined occurs. Therefore, it is necessary to set the threshold value in view of the balance between suppression of erroneous determination due to individual differences among operators and improvement in operability.

JP 2013-117900 A

  However, since the difference in detection values due to the individual difference is large in practice, it is difficult to improve the balance, and it is difficult to achieve both suppression of erroneous determination and improvement in operability.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a capacitance type operating device that can realize both suppression of erroneous determination and improvement in operability.

  The invention disclosed herein employs the following technical means to achieve the above object. Note that the reference numerals in parentheses described in the claims and in this section indicate the correspondence with the specific means described in the embodiments described later, and do not limit the technical scope of the invention. .

  One of the disclosed inventions is a capacitive operation device, and an operation plate (10) that forms an operation surface (11, 12, 13, 14, 15, 16) that is operated by contact with an operation body (F). And a contact determination means (46) for determining that a contact operation in which the operating body comes into contact with the operating surface or a separating operation in which the operating body in contact with the operating surface is separated from the operating surface has been performed. And Then, detection according to the amount of change in capacitance generated between the electrode (21, 22, 23, 24, 25, 26) located on the opposite side of the operation body with respect to the operation surface and the operation body and the electrode. The unit of change rate during the change period (Tup, Tdw) in which the detection means (41) for acquiring the value and the change rate (V1, V2, V3, V4) of the detection value are equal to or higher than the predetermined rate (Vth) Sudden change phenomenon determining means (42) for determining whether or not a sudden change phenomenon in which the amount of change per time is equal to or greater than a predetermined amount (ΔVth) has occurred, and the contact determination means causes the sudden change phenomenon to appear. It is determined that a contact operation or a separation operation is performed on the condition that it is determined that the operation has been performed.

  As illustrated in FIG. 4, in the process of performing the contact operation, the detected value changes in inverse proportion to the distance between the operation body and the electrode until the operation body comes into contact with the operation surface (see t1 to t2). . Therefore, if the moving speed of the operating tool is constant, the change speed of the detection value changes in inverse proportion to the separation distance. However, after the contact operation is performed, even if the moving speed of the operating body is constant, the change rate of the detected value increases rapidly (see t2 to t4). Further, in the process of performing the separation operation, the detection value changes in inverse proportion to the separation distance between the operation body and the electrode after the operation body is separated from the operation surface (see t7 to t8). However, until the operating body moves away from the operating surface, the change rate of the detected value increases rapidly (see t5 to t7).

  In short, the change rate of the detected value changes abruptly before and after the operating body contacts or leaves the operating surface. The degree of sudden change in the detected value is not easily influenced by individual differences among operators. Nevertheless, when the operating body is brought close to the operation surface but is not brought into contact, for example, when the contact operation is stopped halfway, the sudden change phenomenon does not appear. In addition, when the operating body is slightly moved away from the operating surface while being in contact with the operating surface by weakening the force that presses the operating body against the operating surface, for example, when the separation operation is stopped halfway, the sudden change phenomenon is Does not appear.

  In the above invention in view of these findings, it is determined that a contact operation or a separation operation has been performed on the condition that a sudden change phenomenon in which the change rate of the detection value increases during the change period of the detection value appears. Therefore, the presence or absence of the contact operation or the separation operation can be determined with high accuracy. Therefore, it is possible to realize both suppression of erroneous determination and improvement in operability.

  Further, one of the disclosed inventions is the above-described electrostatic capacity type operating device, and electrodes (21, 22, 23, 24, 25, 26) located on the opposite side of the operating body with respect to the operating surface. And a detection means (41) for acquiring a detection value corresponding to the amount of change in capacitance generated between the operating body and the electrode, and the contact determination means has a predetermined threshold value (Cth). It is characterized in that it is determined that a contact operation or a separation operation has been performed on the condition that the change speed (V2, V3) of the detection value when changing so as to straddle is equal to or higher than a predetermined speed (Vtha).

  As described above, the change rate of the detected value changes abruptly before and after the operating body contacts or leaves the operating surface. Therefore, in the process of performing the contact operation, the increase speed (change speed) when the detection value increases beyond the threshold value is likely to be greater than the predetermined speed. In the process of performing the separation operation, the absolute value (change speed) of the decrease speed when the detection value decreases beyond the threshold value is likely to be greater than the predetermined speed.

  In the above invention in view of these findings, it is determined that the contact operation or the separation operation has been performed on the condition that the change speed of the detection value when the detection value changes so as to cross the threshold is equal to or higher than a predetermined speed. To do. Therefore, the presence or absence of the contact operation or the separation operation can be determined with high accuracy. Therefore, it is possible to realize both suppression of erroneous determination and improvement in operability.

The perspective view which shows the vehicle mounting position of the electrostatic capacitance type operating device concerning 1st Embodiment of this invention. The front view of the electrostatic capacitance type operating device shown in FIG. Sectional drawing which follows the III-III line | wire of FIG. The figure which shows the one aspect | mode of a detected value change at the time of contact operation and separation operation. The flowchart which shows the process sequence which determines the presence or absence of contact operation in 1st Embodiment. The flowchart which shows the process sequence which determines the presence or absence of separation operation in 1st Embodiment. The flowchart which shows the process sequence which determines the presence or absence of contact operation in 2nd Embodiment of this invention. The flowchart which shows the process sequence which determines the presence or absence of separation operation in 2nd Embodiment.

  Hereinafter, a plurality of modes for carrying out a capacitive operation device according to the present invention will be described with reference to the drawings. In each embodiment, portions corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals and redundant description may be omitted. In each embodiment, when only a part of the configuration is described, the other configurations described above can be applied to other portions of the configuration.

(First embodiment)
FIG. 1 is a perspective view of an instrument panel (instrument panel Vi) mounted on a vehicle V as viewed from the indoor side. An electrostatic capacity type operating device Vo is assembled in the central portion of the instrument panel Vi in the left-right direction of the vehicle. This electrostatic capacity type operating device Vo is premised on being operated by a vehicle occupant, and is disposed at a position that can be operated from either the driver seat Dr or the passenger seat Pa in the passenger compartment. As shown in FIGS. 2 and 3, the electrostatic capacitance type operating device Vo includes an operation plate 10, an electrode sheet 20, and a printed wiring board 30 described below.

  The operation plate 10 is a resin plate member and forms a decorative surface 10a that is visually recognized by the user. The decorative surface 10 a has a plurality of operation surfaces 11, 12, 13, 14, 15, and 16. On these operation surfaces 11 to 16, characters, symbols, figures, and the like representing the setting contents of the operation target are printed. In the example illustrated in FIG. 1, the operation target is an air conditioner 50 that air-conditions the interior of the vehicle. For example, activation of the air conditioner 50, air volume setting, temperature setting, and the like can be given as specific examples of the setting contents. When the user touches the operation surfaces 11 to 16 with the fingertip F, a command signal for instructing the corresponding device to operate is output, and the air conditioner 50 operates according to the content of the contact operation.

  An electrode sheet 20 is attached to the surface of the operation plate 10 opposite to the decorative surface 10a. The electrode sheet 20 has a plurality of electrodes 21, 22, 23, 24, 25, and 26, and these electrodes 21 to 26 are held by a resin sheet 20a. Each of the electrodes 21 to 26 is disposed so as to face the corresponding operation surfaces 11 to 16.

  A printed wiring board 30 is disposed on the opposite side of the operation plate 10 with respect to the electrode sheet 20. A plurality of light sources 31, 32, and 33 are mounted on the circuit board, and these light sources 31 to 33 are arranged to face the corresponding electrodes 21 to 26. Transparent electrodes such as indium tin oxide are used for the electrodes 21 to 26. In addition, a light-transmitting resin member is employed for the operation plate 10, and portions of the operation surfaces 11 to 16 that are not printed are transmitted and illuminated by the light sources 31 to 33. In addition, the coating material which has light-shielding property is printed in parts other than the operation surfaces 11-16 among the decoration surfaces 10a.

  The electrodes 21 to 26 output voltage changes that occur according to changes in capacitance as electrical signals. The electrical signals output from the electrodes 21 to 26 are input to a microcomputer (microcomputer 40) mounted on the printed wiring board 30. The microcomputer 40 includes a storage device that stores a program and a central processing unit that executes arithmetic processing according to the stored program. The microcomputer 40 functions as a detection unit 41, a sudden change determination unit 42, a level determination unit 43, a continuation determination unit 44, a change unit 45, and a contact determination unit 46 described below by executing various arithmetic processes ( (See FIG. 2).

  The electrostatic capacitance type operating device Vo includes a circuit that repeatedly charges and discharges the coupling capacitance formed by the electrodes 21 to 26, and the detection unit 41 counts the number of times of charging and discharging until a predetermined condition is satisfied. The count value increases as the capacitance generated between the electrodes 21 to 26 and the fingertip F increases. Therefore, based on the count value, the detection means 41 calculates a “detection value” corresponding to the amount of change in capacitance that occurs between the electrodes 21 to 26 and the fingertip F. Specifically, when the count value when the fingertip F is sufficiently separated from the electrodes 21 to 26 is referred to as a reference value, the count value when the fingertip F is in the vicinity of the electrodes 21 to 26 or the contact position The difference from the reference value is calculated as the detected value.

  FIG. 4 shows a detection waveform representing a time change of the detection value. From this detected waveform, high frequency components due to electrical noise or the like are removed. The sudden change determination means 42 determines whether or not a waveform of a sudden change phenomenon (rapid change waveform) described below appears in the rising change period Tup or the decrease change period Tdw of the detected waveform.

  In the period from t1 to t4 in which the contact operation in which the fingertip F is brought into contact with the operation surfaces 11 to 16 is performed, the detection value gradually increases as the fingertip F approaches the operation surfaces 11 to 16. The period from t1 to t4 is referred to as an ascending change period Tup. In the ascending change period Tup, the detection value increasing speeds V1 and V2 are equal to or higher than the predetermined speed Vth. The increasing speeds V1 and V2 of the detected value in the rising change period Tup are rapidly increased at time t2 when the contact of the fingertip F with the operation surfaces 11 to 16 is started. This phenomenon is a sudden change phenomenon, and the waveform of the portion including the time t2 in the detected waveform corresponds to the sudden change waveform.

  In addition, in the period from t5 to t8 when the fingertip F that has been in contact with the operation surfaces 11 to 16 is separated from the operation surfaces 11 to 16, the detected value gradually decreases as the fingertip F moves away from the operation surfaces 11 to 16. I will do it. This period from t5 to t8 is referred to as a decrease change period Tdw. In the decrease change period Tdw, the absolute values of the detection value decrease speeds V3 and V4 are equal to or higher than a predetermined speed Vth. In the decrease change period Tdw, the decrease rate of the detected value is large in the period from t5 to t7 in which the fingertip F leaves the operation surfaces 11 to 16 while being in contact, and the time point t7 when the fingertip F is completely separated from the operation surfaces 11 to 16 Thereafter, the decrease rate of the detected value becomes gentle. The decrease speeds V3 and V4 of the detected value in the decrease change period Tdw are rapidly decreased at time t7 when the fingertip F starts to be separated from the operation surfaces 11 to 16. This phenomenon is a sudden change phenomenon, and the waveform of the portion including the time t7 in the detected waveform corresponds to the sudden change waveform.

  Here, the principle of the sudden change phenomenon will be described below. The electrostatic capacitance C generated between the electrode 21 and the fingertip F can be approximately calculated by a combined capacitance 1 / C = 1 / C1 + 1 / C2 of C1 and C2 connected in series. C1 is ε0 · εr1 · S / d1, and C2 is ε0 · εr2 · S / d2. ε0 is the dielectric constant of vacuum, εr1 is the relative dielectric constant of the operation plate 10 which is a substance (interelectrode medium) interposed between the electrode and the fingertip F, and S is the lap area of the electrode area and the fingertip F as a parallel plate capacitor , D1 represents the thickness of the operation plate 10. Further, εr2 represents the relative permittivity of air as an interelectrode medium, and d2 represents the distance between the fingertip F and the operation plate 10.

  In the period from t2 to t7 in FIG. 4 in which the fingertip F is in contact with the operation surface, the operation plate 10 corresponds to the interelectrode medium. On the other hand, in the period t1 to t2 or the period t7 to t8 in which the fingertip F is away from the operation surface, in addition to the operation plate 10, air interposed between the operation plate 10 and the fingertip F also corresponds to the interelectrode medium. Accordingly, the capacitance detected at the time t2 when the contact state is switched to the contact state is rapidly increased, and the capacitance detected at the time t7 when the contact state is switched to the non-contact state is rapidly decreased.

  Further, at the time t2 when the fingertip F starts to contact, the contact area S is small because the fingertip F only touches the operation surface 11 lightly. However, when the fingertip F is further pressed against the operation surface 11 during the period from t2 to t4, the fingertip F is crushed and the contact area S increases. Similarly, when the fingertip F pressed against the operation surface 11 is released during the period from t5 to t7, the crushed fingertip F is released, and the contact area S is reduced.

  In this way, until the time t2 in the rising change period Tup, it gradually increases in accordance with the combined capacitance 1 / C = 1 / C1 + 1 / C2 of the series connection of C1 and C2. On the other hand, after time t2, an increase in relative permittivity εr and an increase in contact area S occur, and the detected value increases rapidly according to C1 = ε0 · εr1 · S / d1. Therefore, at time t2, a sudden change phenomenon occurs in which the amount of change per unit time of the change rate of the detected value, that is, the rising acceleration of the detected value becomes equal to or greater than the predetermined amount ΔVth. Note that εr = εr1 · εr2.

  Similarly, since the relative permittivity εr decreases and the contact area S decreases until the time t7 in the decreasing change period Tdw, the detected value decreases rapidly according to C1 = ε0 · εr1 · S / d1. On the other hand, after time t7, the capacitance gradually decreases in accordance with the combined capacitance 1 / C = 1 / C1 + 1 / C2 of the series connection of C1 and C2. Therefore, at time t7, a sudden change phenomenon occurs in which the amount of change per unit time of the change rate of the detection value, that is, the decrease acceleration of the detection value becomes equal to or greater than the predetermined amount ΔVth.

  The level determining means 43 determines whether or not a high level state in which the detected value exceeds a predetermined threshold Cth (see FIG. 4) appears in the rising change period Tup or the decreasing change period Tdw. In the example of FIG. 4, the detected value increases and reaches a predetermined threshold Cth at time t3 after time t2 in the increase change period Tup. In addition, the detection value decreases and reaches the threshold value Cth at time t6 before time t7 in the decrease change period Tdw. That is, it is in the high level state during the period from t3 to t6.

  The continuation determination unit 44 determines whether or not the high level state has been maintained for a predetermined duration Tth (see FIG. 4) after the time t3 when the state has changed to the high level state in the rising change period Tup. Further, the continuation determination unit 44 determines whether or not the normal level state is maintained for the duration Tth or more after the time t6 when the detection value changes to the normal level state where the detection value is less than the threshold Cth in the decrease change period Tdw. . The duration Tth is changed by the changing unit 45 in accordance with the user operation status.

  Specifically, the microcomputer 40 acquires whether or not the vehicle V is traveling as information on the operation status. For example, information on whether or not the vehicle V is traveling is acquired as operation status information. If the vehicle is traveling, it can be said that it is an operation situation (unstable operation situation) in which the fingertip F is less likely to be positioned at the intended position due to running vibration of the vehicle V. On the other hand, when traveling is stopped, it can be said that there is no traveling vibration, so that the operation state (stable operation state) is easily determined at the position where the fingertip F is intended. The changing means 45 changes the duration Tth in the unstable operation situation (during traveling) to a time longer than the duration Tth in the stable operation situation (during running stop).

  The contact determination unit 46 determines whether a contact operation or a separation operation has been performed based on the determination results of the sudden change determination unit 42, the level determination unit 43, and the continuation determination unit 44. When the contact operation is performed, the microcomputer 40 changes the setting content of the air conditioner 50 associated with the corresponding operation surface. Specific examples of the setting include the above-described activation of the air conditioner, air volume setting, temperature setting, and the like. The microcomputer 40 outputs a command signal corresponding to the above setting to the air conditioner 50 and controls the operation of the air conditioner 50. In addition to the air conditioner 50, the electrostatic capacity type operating device Vo can also function the audio device 51 and the navigation device 52 as an operation target. In this case, the microcomputer 40 outputs a command signal corresponding to the setting content by the capacitance type operating device to the audio device 51 and the navigation device 52, and controls the operation of these devices 51 and 52.

  After the continuation time Tth has elapsed from the time point t3, the microcomputer 40 performs an increment process according to the time during which the high level state is maintained (long press time). For example, the longer the long press time, the higher the increment value, and the air volume setting and temperature setting values are changed corresponding to the increment value. This increment processing ends when it is determined that the separation operation has been performed.

  FIG. 5 is a flowchart showing a processing procedure for determining whether or not a contact operation has been performed by the above-described means 41, 42, 43, 44, 45, 46. This processing is performed by the microcomputer 40 at a predetermined cycle. It is executed repeatedly. In addition, the white circle in FIG. 4 has shown the sampling value of the detected value, and the code | symbol ta in the figure shows a sampling period (for example, 20 milliseconds). This sampling period is made to coincide with the predetermined period according to FIG.

  First, in step S10 of FIG. 5, it is determined whether or not the detection value sampled this time is sampled during the rising change period Tup. Specifically, when the difference between the current detection value and the previous detection value is greater than or equal to a predetermined value, the increase speeds V1 and V2 are considered to be greater than or equal to the predetermined speed Vth, and the increase change period Tup. judge.

  When it is determined that the rising change period Tup, the determination by the sudden change determination unit 42 is performed in the subsequent step S11. That is, it is determined whether or not a sudden change waveform in which the change amount per unit time of the change rate of the detected value appears more than the predetermined amount ΔVth appears during the rising change period Tup. Specifically, when the difference between the current increase speed V2 and the previous increase speed V1 is equal to or greater than a predetermined amount ΔVth, it is determined that a sudden change waveform has appeared.

  If it is determined that a sudden change waveform has appeared, determination by the level determination means 43 is performed in the subsequent step S12. That is, it is determined whether or not a high level state has occurred during the rising change period Tup. Specifically, when the current detection value is equal to or greater than the threshold value Cth, it is determined that the state is the high level state.

  If it is determined that the state is the high level state, the duration Tth is changed by the changing means 45 in accordance with the vehicle speed in the subsequent step S13. Specifically, the duration Tth is set according to whether the vehicle is stopped at zero speed, is traveling at a low speed below a predetermined speed, or is traveling at a high speed above a predetermined speed. It has been changed in three stages. When traveling, the duration Tth is set longer than when the vehicle is stopped. In addition, the duration time Tth is set longer during high speed travel than during low speed travel.

  In the subsequent step S14, the determination by the continuation determination unit 44 is performed. That is, it is determined whether or not the duration Tth has elapsed while maintaining a high level state in which the detection value is equal to or greater than the threshold value Cth. When it is determined that the high level state is maintained for the duration time Tth, it is determined in the next step S15 that the contact operation has been performed. Then, the switch signal associated with the operation surface on which the contact operation is performed is turned on. If a negative determination is made in at least one of steps S10, S11, S12, and S14, it is not determined that the contact operation has been performed.

  FIG. 6 is a flowchart showing a processing procedure for determining whether or not the separation operation has been performed by each of the above-described means 41, 42, 43, 44, 45, 46. This processing is performed by the microcomputer 40 at a predetermined cycle. It is executed repeatedly. First, in step S20 of FIG. 6, it is determined whether or not the detected value sampled this time is sampled during the decrease change period Tdw. Specifically, when the difference between the current detection value and the previous detection value is greater than or equal to a predetermined value, the absolute values of the current decrease speeds V3 and V4 are greater than or equal to the predetermined speed Vth. It is determined that it is the decrease change period Tdw.

  When it is determined that the decrease change period Tdw is reached, in the subsequent step S21, determination by the sudden change determination means 42 is performed. That is, it is determined whether or not a sudden change waveform in which the change amount per unit time of the change rate of the detection value appears more than the predetermined amount ΔVth during the decrease change period Tdw is determined. Specifically, when the difference between the absolute value of the previous decrease speed V3 and the absolute value of the previous decrease speed V4 is equal to or greater than a predetermined amount ΔVth, it is determined that a sudden change waveform has appeared.

  When it is determined that a sudden change waveform has appeared, determination by the level determination unit 43 is performed in the subsequent step S22. That is, it is determined whether or not a high level state appears during the decrease change period Tdw. Further, it is determined whether or not the high level state has changed to the normal level state. Specifically, if the detected value is equal to or greater than the threshold value Cth, it is determined that a high level state has appeared. Then, when the previous detection value is equal to or greater than the threshold Cth and the current detection value is less than the threshold Cth, it is determined that the high level state has changed to the normal level state.

  If it is determined that the state has changed to the normal level state, in the subsequent step S23, the changing means 45 changes the duration Tth according to the vehicle speed. Specifically, the duration Tth is set according to whether the vehicle is stopped at zero speed, is traveling at a low speed below a predetermined speed, or is traveling at a high speed above a predetermined speed. It has been changed in three stages. When traveling, the duration Tth is set longer than when the vehicle is stopped. In addition, the duration time Tth is set longer during high speed travel than during low speed travel.

  In subsequent step S24, determination by the continuation determination means 44 is performed. That is, it is determined whether or not the duration Tth has elapsed while maintaining the normal level state where the detection value is less than the threshold value Cth. When it is determined that the normal level state is maintained for the duration time Tth, it is determined in the next step S25 that the separation operation has been performed. Then, the switch signal associated with the operation surface on which the separation operation is performed is turned off. If a negative determination is made in at least one of steps S20, S21, S22, and S24, it is not determined that the separation operation has been performed.

  As described above, at the time of the contact operation and the separation operation, the detected value changes rapidly as the relative permittivity εr and the contact area S change rapidly. That is, a sudden change waveform appears in the detected waveform. The presence or absence of the sudden change waveform is not easily affected by the individual difference of the fingertip F, and when the fingertip F is not brought into contact with the operation surface 11 or the separation operation is stopped halfway, the sudden change waveform is generated. Does not appear. In the present embodiment in view of these points, the presence / absence of a contact operation or a separation operation is determined on condition that an abrupt change waveform appears. Therefore, the determination can be made with high accuracy. Therefore, it is possible to realize both suppression of erroneous determination and improvement in operability.

  Now, due to electrical noise or a sudden change in ambient temperature, a sudden change waveform may appear even though no contact operation is performed. However, in this case, there is a high possibility that the detected value is not in the high level state that is equal to or higher than the threshold value Cth. It is assumed that the sudden change in the atmospheric temperature occurs when high temperature outside air flows into the room by opening the door during cooling of the vehicle interior or when low temperature outside air flows during heating.

  In view of this point, in the present embodiment, it is determined that the contact operation has been performed on the condition that the high-level state appears in the rising change period Tup in addition to the condition for the sudden change waveform appearance. Further, it is determined that the separation operation has been performed on the condition that the high level state appears in the decrease change period Tdw in addition to the condition for the sudden change waveform appearance. Therefore, it is possible to reduce the risk of erroneous determination due to electrical noise or a sudden change in ambient temperature. Even if it is determined that the state is the high level state, it is not determined that the contact operation or the separation operation is performed unless the appearance of the sudden change waveform is detected. Therefore, the threshold value Cth used for the determination of the high level state can be set to a value sufficiently lower than the threshold value used for the contact determination in Patent Document 1. Therefore, in this embodiment, it can suppress that determination of a high level state becomes a different result resulting from the individual difference of the fingertip F.

  Furthermore, in this embodiment, the continuation determination means 44 is provided that determines whether or not the high level state or the normal level state has been maintained for a predetermined duration Tth or longer. Then, in addition to the condition of sudden change waveform appearance, it is determined that the contact operation has been performed on the condition that the high level state is maintained for the duration Tth or longer. Further, it is determined that the separation operation has been performed on the condition that the normal level state is maintained for the duration Tth or longer.

  According to this, even when an erroneous operation occurs in which the fingertip F touches the unintended operation surface, it is difficult to determine that the contact operation has been performed. Further, even when an erroneous operation occurs in which the fingertip F is separated from the operation surface against the intention, it is difficult to determine that the separation operation has been performed. Therefore, it is difficult to determine whether the switch is turned on due to an erroneous operation.

  Here, the threshold value Cth used in the stable operation situation is set in consideration of a balance between suppression of erroneous determination caused by individual differences among operators and improvement in operability. That is, if the threshold value Cth is set low, it is promoted that the ON determination is made only by lightly touching the operation surface, and the operability is improved. On the other hand, when the operator's fingertip F is large or the fingertip F is wet with sweat, the detected value appears large. Therefore, if the threshold value Cth is excessively lowered, it is turned on only by bringing the fingertip F close to the operation surface. Opportunities for misjudgment such as being judged increase.

  On the other hand, in an unstable operation situation, an erroneous operation in which the fingertip F touches an unintended operation surface is likely to occur. In this type of erroneous operation, unlike the erroneous determination described above, the fingertip F actually touches the operation surface. Therefore, there is a high possibility that the detected value exceeds the threshold value Cth and a sudden change waveform appears. Therefore, it is not sufficient to raise the threshold value Cth to suppress the ON determination at the time of erroneous operation. However, the contact time is likely to be shorter during an erroneous operation than during the intended operation.

  In the present embodiment, which focuses on this point, since the change unit 45 that changes the duration Tth according to the operation situation of the fingertip F is provided, the duration Tth can be changed longer in an unstable operation situation. Therefore, it is possible to suppress the ON determination at the time of an erroneous operation without changing the threshold value Cth extremely high. Therefore, without erroneously reducing the balance between the reduction of misjudgment caused by individual differences between operators and the improvement of operability such as turning on just by lightly touching the operation surface, it is possible to turn on at the time of erroneous operation in unstable operation situations. Judgment can be suppressed.

  Further, in the present embodiment, information related to vehicle running vibration is acquired as an operation status, and the duration Tth is changed by the changing unit 44. It can be said that it is an operation situation (unstable operation situation) in which the fingertip F is less likely to be positioned at the intended position as the traveling vibration is larger. Therefore, the duration Tth can be changed with good timing when an unstable operation situation occurs.

  Furthermore, in this embodiment, the duration Tth is changed to a longer time as the traveling vibration is larger. Therefore, the greater the degree that the fingertip F is less likely to be positioned at the intended position, the more the duration Tth value is changed to a value that makes it difficult to determine the touch operation or the separation operation. Therefore, it is possible to avoid excessive ON determination suppression during erroneous operation in unstable operation situations, and unnecessarily balance the balance between suppression of erroneous determination due to individual differences between operators and improvement in operability. Can be avoided.

  Furthermore, in this embodiment, if it is not the rising change period Tup, even if a sudden change waveform appears, it is not determined as a touch operation. Therefore, even when a sudden change waveform appears due to noise or the like in a period in which the detection value before time t1 in FIG. 4 hardly changes, erroneous determination that the touch operation has been performed is suppressed. Similarly, since it is not determined as a separation operation even if a sudden change waveform appears unless the change period Tdw, an erroneous determination that the separation operation has been performed due to noise or the like is suppressed.

(Second Embodiment)
In the first embodiment, the presence or absence of the contact operation or the separation operation is determined on the condition that the suddenly changing waveform appears. On the other hand, in the present embodiment, the contact operation or separation is performed on the condition that the increase speed V2 and decrease speed V3 of the detection value when the detection value changes so as to cross the threshold value Cth is equal to or higher than the predetermined speed Vtha. Determine if there is an operation. The hardware configuration of the capacitive operating device according to the present embodiment is the same as that of the first embodiment.

  Hereinafter, the determination procedure of the contact operation and the separation operation according to the present embodiment will be described with reference to FIGS. 7 and 8. The process of the flowchart shown in the figure is repeatedly executed by the microcomputer 40 at a predetermined cycle.

  First, in step S30 of FIG. 7, it is determined whether or not the detected value has changed so as to increase across the threshold value Cth. Specifically, when the previous sampling value is less than the threshold value Cth and the current sampling value is greater than or equal to the threshold value Cth, it is determined that the detected value has increased and changed across the threshold value Cth.

  If it is determined that the change has increased across the threshold value Cth, whether or not the increase speed (change speed) of the detected value at the time of the increase change is equal to or higher than a predetermined speed Vtha set in advance in step S31. Determine. Specifically, the difference between the current sampling value and the previous sampling value is regarded as a change speed in the sampling period ta, and whether or not the absolute value of the increase speed V2 calculated from the difference is equal to or higher than a predetermined speed Vtha. Determine.

  When it is determined that the speed is equal to or higher than the predetermined speed Vtha, in the subsequent step S32, the duration time Tth is changed in the same manner as in step S13 of FIG. In the subsequent step S33, similarly to step S14 in FIG. 5, it is determined whether or not the duration Tth has elapsed while maintaining the high level state in which the detection value is equal to or greater than the threshold value Cth. When it is determined that the high level state is maintained for the duration time Tth, it is determined in the next step S34 that the contact operation has been performed. Then, the switch signal associated with the operation surface on which the contact operation is performed is turned on. If a negative determination is made in at least one of steps S30, S31, and S33, it is not determined that the contact operation has been performed.

  Next, in step S40 of FIG. 8, it is determined whether or not the detected value has changed so as to decrease across the threshold value Cth. Specifically, when the previous sampling value is equal to or greater than the threshold value Cth and the current sampling value is less than the threshold value Cth, it is determined that the detected value has changed and decreased across the threshold value Cth.

  If it is determined that the change has decreased across the threshold Cth, in the subsequent step S41, whether or not the decrease rate (change rate) of the detected value at the time of the decrease is equal to or higher than a preset predetermined velocity Vtha. Determine. Specifically, the difference between the current sampling value and the previous sampling value is regarded as the change speed in the sampling period ta, and whether or not the absolute value of the decrease speed V3 calculated from the difference is equal to or higher than a predetermined speed Vtha. Determine.

  When it is determined that the speed is equal to or higher than the predetermined speed Vtha, in the subsequent step S42, the duration Tth is changed in the same manner as in step S23 of FIG. In the subsequent step S43, similarly to step S24 in FIG. 6, it is determined whether or not the duration Tth has elapsed while maintaining the normal level state in which the detection value is less than the threshold value Cth. When it is determined that the normal level state is maintained for the duration time Tth, it is determined in the next step S44 that the separation operation has been performed. Then, the switch signal associated with the operation surface on which the separation operation is performed is turned off. If a negative determination is made in at least one of steps S40, S41, and S43, it is not determined that the separation operation has been performed.

  As described above, at the time of the contact operation and the separation operation, the detected value changes rapidly as the relative permittivity εr and the contact area S change rapidly. Therefore, in the process of performing the contact operation or the separation operation, there is a high possibility that the change speed of the detection value when the detection value changes across the threshold value Cth is equal to or higher than the predetermined speed Vtha. In addition, when the fingertip F is brought close to the operation surface 11 but not touched or when the separation operation is stopped halfway, even if the detection value changes across the threshold value Cth, the detection value does not change suddenly. The change speed at that time is likely to be less than the predetermined speed Vtha.

  In this embodiment in view of these points, the contact operation is performed on the condition that the increase speed V2 or the decrease speed V3 of the detection value when the detection value changes across the threshold value Cth is equal to or higher than the predetermined speed Vtha. Or the presence or absence of separation operation is determined. Therefore, the determination can be made with high accuracy. Therefore, it is possible to realize both suppression of erroneous determination and improvement in operability.

(Third embodiment)
In the present embodiment, information (Dr / Pa information) indicating whether the operator of the capacitive operating device Vo is an occupant seated in the driver seat Dr or the passenger seat Pa of the vehicle V is acquired. For example, if it is determined on which side the operator is an occupant based on the detection results of an infrared sensor or camera that detects the movement of the upper body of the occupant, seating sensors provided in the driver's seat Dr and the passenger seat Pa, etc. Good.

  Now, as a specific example of the operation situation in which the fingertip F is difficult to be determined at the intended position, there is a case where it is difficult to be determined due to the poor operation posture in addition to the case where the fingertip F is difficult to be determined due to running vibration. For example, the occupant of the driver's seat Dr is limited in the degree of freedom of the operation posture as compared with the occupant of the passenger seat Pa. Therefore, the fingertip F is less likely to be set at the intended position than the occupant of the passenger seat Pa. Therefore, in the present embodiment, when the passenger on the driver's seat Dr side is operating, the duration Tth is set longer than when the passenger on the passenger seat Pa side is operating.

  Here, in an erroneous operation in which the fingertip F touches the unintended operation surface due to the poor operation posture, there is a high possibility that a suddenly changing waveform appears, and the detection value may exceed the threshold value Cth. Is expensive. However, in this type of erroneous operation, the contact time is likely to be shorter than in the intended operation.

  In this embodiment focusing on this point, in the case of an operation by the driver's seat Dr side occupant, the duration Tth is made longer than in the case of the operation by the passenger's seat Pa side occupant. Become so.

(Other embodiments)
The present invention is not limited to the description of the above embodiment, and may be modified as follows. Moreover, you may make it combine the characteristic structure of each embodiment arbitrarily, respectively.

  In the embodiment shown in FIG. 5, the touch operation is performed when all three conditions of appearance of a suddenly changing waveform (S11: YES), high level state (S12: YES), and continuation of the high level state (S14: YES) are satisfied. It is determined that. On the other hand, at least one of the two conditions such as the high level state and the continuation of the high level state may be abolished. Similarly, in the embodiment shown in FIG. 6, at least one of the two conditions such as the normal level state (S22: YES) and the continuation of the normal level state (S24: YES) may be abolished.

  In the embodiment shown in FIGS. 7 and 8, it is determined that the contact operation or the separation operation is performed when all of the following two conditions are satisfied. That is, there are conditions such as V2, V3 ≧ Vtha (S31: YES) (S41: YES) and continuation of the state (S33: YES) (S43: YES) when the threshold Cth is exceeded. On the other hand, conditions such as continuation of the high level state or the normal level state may be abolished.

  Since the detected value becomes higher as the atmospheric humidity on the operation surfaces 11 to 16 is higher, if the predetermined speed Vth, the threshold value Cth, and the duration Tth used for various determinations are changed according to the humidity, erroneous determination can be suppressed and operability can be improved. Compatibility with improvement can be improved. For example, the higher the humidity, the larger the predetermined speed Vth, the higher the threshold Cth, and the longer the duration Tth.

  In each of the above embodiments, the vehicle speed is acquired as information related to the traveling vibration of the vehicle V, and the duration Tth is changed according to the vehicle speed. On the other hand, you may acquire the detected value of the acceleration sensor which detects the traveling acceleration of the vehicle V as information regarding traveling vibration. Also, paying attention to the fact that the detection values of the sensors that detect the attitude of the vehicle V, such as the pitching angle and yawing angle of the vehicle V, have a high correlation with the degree of vibration of the vehicle V, these detection values are acquired as information related to running vibration. May be.

  In the embodiment shown in FIGS. 5, 6, 7 and 8, the duration Tth is changed according to the operation status. On the other hand, the predetermined speed Vth and the threshold value Cth used for various determinations may be changed according to the operation situation.

  In the embodiment shown in FIG. 5, FIG. 6, FIG. 7 and FIG. 8, in setting the duration time Tth according to the vehicle speed, the duration time Tth is switched in three stages: stop, low speed travel and high speed travel. . On the other hand, the switching may be performed in two stages at the time of stopping and traveling, or may be switched in four or more stages.

  Since the relative dielectric constant of the operation plate 10 changes depending on the temperature, the detected value changes depending on the temperature. In view of this, the predetermined speed Vth, threshold Cth, and duration Tth used for various determinations may be changed according to the temperature.

  In the embodiment shown in FIG. 3, the electrodes 21 to 26 are structured to be held inside the sheet 20a. Instead of this structure, the electrodes 21 to 26 may be printed on the surface of the sheet 20a.

  In the embodiment shown in FIG. 3, a self-capacitance type device is employed in which the capacitance of the electrodes 21 to 26 increases when the fingertip F is brought close to the electrodes 21 to 26. On the other hand, you may employ | adopt the mutual capacitance system provided with a receiving electrode with respect to each of the electrodes 21-26. In the mutual capacitance method, when the fingertip F is brought close to the electrodes 21 to 26, the electric field generated between the electrodes 21 to 26 and the reception electrode is reduced, and the charge of the reception electrode is reduced. The electrodes 21 to 26 or the receiving electrodes output an electrical signal corresponding to the decrease in the electric charge.

  In the embodiment shown in FIG. 1, the present invention is applied to the capacitive operation device Vo mounted on the vehicle V, but the present invention is not limited to the one mounted on the vehicle V.

  In each of the above embodiments, it is assumed that the user's fingertip F is operated while being in contact with the operation surfaces 11 to 16, and the fingertip F is used as the operating body. On the other hand, for example, the user may hold a pen-shaped operation member and operate it by bringing the operation member into contact with the operation surfaces 11 to 16. In this case, an operation member other than the human body functions as the operation body. . Further, when the user performs a contact operation on the operation surfaces 11 to 16 while wearing gloves, the gloves function as an operation body.

  DESCRIPTION OF SYMBOLS 10 ... Operation plate 11, 12, 13, 14, 15, 16 ... Operation surface 21, 22, 23, 24, 25, 26 ... Electrode, 41 ... Detection means, 42 ... Rapid change determination means, 46 ... Contact determination means F ... fingertip (operating body), Tup ... rising change period (change period), Tdw ... decrease change period (change period), V1, V2, V3, V4 ... change rate of detected value, Vth ... predetermined speed, [Delta] Vth ... Predetermined amount.

Claims (6)

An operation plate (10) that forms an operation surface (11, 12, 13, 14, 15, 16) to be contact-operated by the operation body (F);
A contact determining means (46) for determining that a contact operation in which the operating body comes into contact with the operating surface or a separating operation in which the operating body in contact with the operating surface is separated from the operating surface has been performed. In the capacitive operation device,
Electrodes (21, 22, 23, 24, 25, 26) located on the opposite side of the operation body with respect to the operation surface;
Detection means (41) for acquiring a detection value corresponding to the amount of change in capacitance generated between the operating body and the electrode;
During the change period (Tup, Tdw) in which the change speed (V1, V2, V3, V4) of the detected value is equal to or higher than the predetermined speed (Vth), the change amount per unit time of the change speed is a predetermined amount ( Sudden change determination means (42) for determining whether or not a sudden change phenomenon equal to or greater than (ΔVth) has occurred;
With
The capacitance-type operation device, wherein the contact determination unit determines that the contact operation or the separation operation is performed on the condition that the sudden change determination unit determines that the sudden change phenomenon has occurred. Level determining means (43) for determining whether or not a high level state in which the detected value is equal to or greater than a predetermined threshold (Cth) appears in the change period,
The contact determination that the contact operation or the separation operation has been performed on the condition that the sudden change phenomenon is determined by the sudden change determination unit and the high level state is determined by the level determination unit. The electrostatic capacity type operating device according to claim 1, wherein the means is determined. Continuation determining means (44) for determining whether the high level state or the normal level state in which the detection value is less than the threshold is maintained for a predetermined duration (Tth) or more,
The contact determination means that the contact operation or the separation operation has been performed on the condition that the sudden change determination means has determined that the sudden change phenomenon has occurred, and the continuation determination means has determined that the duration has been maintained for a duration or longer. The capacitance type operating device according to claim 2, wherein determination is made.   The electrostatic capacity type operating device according to claim 3, further comprising changing means (45) for changing the duration according to an operating state of the operating body. The operation plate is installed in a vehicle (V).
5. The change means acquires information related to driving vibration of the vehicle as information on the operation status, and changes the duration to a longer time as the driving vibration is larger. Capacitance type operation device described in 1. An operation plate (10) that forms an operation surface (11, 12, 13, 14, 15, 16) to be contact-operated by the operation body (F);
A contact determining means (46) for determining that a contact operation in which the operating body comes into contact with the operating surface or a separating operation in which the operating body in contact with the operating surface is separated from the operating surface has been performed. In the capacitive operation device,
Electrodes (21, 22, 23, 24, 25, 26) located on the opposite side of the operation body with respect to the operation surface;
Detection means (41) for acquiring a detection value corresponding to the amount of change in capacitance generated between the operating body and the electrode;
With
The contact determination means is provided on the condition that a change speed (V2, V3) of the detection value when the detection value changes so as to cross a predetermined threshold (Cth) is equal to or higher than a predetermined speed (Vtha). It is determined that the contact operation or the separation operation has been performed.

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