JP2006347215A - Touch switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a touch switch capable of sensing properly the switch operation made by touching of an operator. <P>SOLUTION: The touch switch has contact sensors installed on steering switches 11a-11f and decides firmly the contacting sensed by the sensor(s) as the operation applied to the steering switches 11a-11f by the operator when the output values of the contact sensors varying according to the contacting condition meet the prescribed conditions, wherein the arrangement further includes auxiliary contact sensors 12a and 12b installed in positions different from the steering switches 11a-11f and a condition correcting means to correct the prescribed conditions according to the output values of the auxiliary contact sensors 12a and 12b varying depending upon the contacting condition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a touch switch that determines a switch operation based on an operator's contact.

  2. Description of the Related Art Conventionally, a technique related to a switch operation for determining an operator's switch operation according to a contact state with an operation unit that receives the switch operation is known (for example, see Patent Documents 1 and 2). These technologies related to the switch operation use a change in the capacitance of the operation unit based on the contact of an operator's finger or the like in order to detect a contact state with the operation unit.

When using a change in capacitance, for example, a predetermined threshold value is set without touching the operation unit, and the operator touches the operation unit when the capacitance exceeds the threshold value. Detection is taking place.
JP 2001-113981 A Japanese Utility Model Publication No. 63-31470

  However, when contact detection is performed with a certain threshold value as in the above-described prior art, even if the operation unit is touched while wearing gloves, the amount of change in capacitance is small and the operation unit is touched. It may not be possible to determine whether or not. In addition, since there are individual differences in the amount of change in capacitance caused by human touch, it may not be possible to determine whether or not the operation unit is touched based on the individual differences.

  Therefore, an object of the present invention is to provide a touch switch that can accurately detect a switch operation caused by contact of an operator.

In order to solve the above problems, according to one aspect of the present invention,
Having detection means for detecting operator contact;
When the output value of the detection unit that varies depending on the contact state satisfies a predetermined condition, the touch switch determines the contact detected by the detection unit as the switch operation of the operator,
Sub-detecting means for detecting contact of an operator installed at a different position from the detecting means;
There is provided a touch switch comprising: a condition correcting unit that corrects the predetermined condition in accordance with an output value of the sub-detecting unit that varies depending on a contact state.

  In this aspect, the sub-detecting means for detecting the contact of the operator is provided at a position different from the detecting means for detecting the contact due to the switch operation by the operator, and the contact state is detected independently of each other. It has become. Therefore, the operator's switch operation can be corrected by using the contact state of the operator detected by the sub-detection unit, so that the condition for determining the switch operation on the detection unit side that detects the contact by the switch operation can be corrected. Can be accurately detected.

  Further, the predetermined condition is a contact determination threshold value, and the condition correction unit determines the contact determination between an output value of the sub detection unit in a non-contact state and an output value of the sub detection unit in a contact state. It is preferable to set a threshold value. Therefore, if the contact determination threshold is corrected within the range between the output values in the non-contact state and the contact state, the operator's switch operation can be accurately detected. At this time, it is preferable that the detection unit and the sub-detection unit detect contact by a change in capacitance.

  Further, in this aspect, the detection unit may be attached to a steering wheel of a vehicle, particularly a spoke portion thereof, and the sub detection unit may be attached to the grip portion. That is, the present invention is used as a steering switch attached to a so-called steering wheel. As a result, the driver can perform the switch operation while holding the steering wheel.

  At this time, the correction by the condition correction unit may be performed only when contact is detected by the sub detection unit. As a result, the correction is performed only when the steering wheel is gripped, and the correction according to the contact state at that time is performed each time the grip is held.

  According to the present invention, it is possible to accurately detect a switch operation due to an operator's contact.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an embodiment (steering switch) when a touch switch according to the present invention is applied to a steering wheel of a vehicle.

  In the example of FIG. 1, the steering wheel 10 is generally composed of a spoke part 13 and a grip part 14. The steering switch 11 includes a left switch group and a right switch group, and is attached to a surface of the spoke portion 13 that faces the driver. Steering switches 11a, 11b, and 11c are arranged as a left switch group on the spoke portion 13a located on the left side of the steering wheel 10. On the other hand, on the spoke portion 13b located on the right side of the steering wheel 10, steering switches 11d, 11e, and 11f are arranged as a right switch group. That is, the steering switches 11a, 11b, and 11c are arranged at positions that allow operation with the left hand (particularly the left thumb) while holding the steering wheel 10. On the other hand, the steering switches 11d, 11e, and 11f are arranged at positions that allow operation with the right hand (particularly, the right thumb) while holding the steering wheel 10.

  Therefore, when the driver operates the steering switch 11 arranged in this way, the vehicle-mounted device corresponding to each steering switch 11 can be operated without releasing the hand from the steering wheel 10. In-vehicle devices include air conditioners, audio, car navigation, communication devices, transmission devices, and the like, but the present invention does not particularly limit the application of this switch.

  In these six steering switches 11 of the present embodiment, a contact detection sensor which is a detection means for detecting contact of an operator (driver) is built in or connected (the steering switch 11 can be said to be the contact detection sensor itself). So it is not shown again). The contact detection sensor detects presence / absence of switch operation (contact presence / absence) using changes in capacitance, pressing force, temperature, etc. caused by the driver touching the steering switch 11 for switch operation. It is.

FIG. 2 is a diagram illustrating a touch switch using a capacitance sensor as a representative example of the contact detection sensor. The capacitance sensor generally has a sensor electrode 35 and a sensor circuit unit 30. The sensor electrode 35 is built in the steering switch 11 so that the switch operation (contact) can be detected. The sensor circuit unit 30 includes a load resistor 31, a sine wave generator 32 that generates a sine wave having a frequency f, a detection diode 33, and a low-pass filter 34. The contact detection is performed by detecting the electrostatic coupling (capacitor) capacitance between the sensor electrode 35 and the human body. When the dielectric constant ε [F / m], the coupling area S [m ² ], and the distance d [m] from the sensor electrode 35, the reactance Xc [Ω] is “Xc = 1 / (2πf · Cd)”, electrostatic The coupling capacitance Cd [F] can be expressed as “Cd = ε · S / d”. In addition, since the principle of contact detection is a well-known technique, further detailed description is abbreviate | omitted. The output value of the capacitance sensor is input to a switch operation confirmation unit 36 that determines and confirms the switch operation.

  The switch operation confirming unit 36 has a predetermined condition for confirming the switch operation, and when the output value of the capacitance sensor satisfies the predetermined condition, the contact detected by the capacitance sensor is detected by the operator's switch. Confirm as operation. The predetermined condition for confirming the switch operation is determined by, for example, a contact determination threshold value, a contact determination calculation formula, and a contact determination map. Therefore, when the driver touches one of the steering switches 11 for the switch operation, the switch operation confirmation unit 36 confirms the switch operation, and the predetermined operations of various in-vehicle devices corresponding to the confirmed switch are executed. The In the case of a contact detection sensor that uses changes in pressing force or temperature, as in the case of the capacitance sensor described above, the output value for the detected pressing force or temperature is input to the switch operation determination unit 36, The switch operation confirmation unit 36 confirms the switch operation.

  In FIG. 1, when the steering switch 11 is operated, the operation state is displayed on the display device 20 in accordance with the operation. Examples of the display device 20 include a head-up display for displaying a display image in front of the windshield, a meter cluster for displaying speed and the like, and a display installed on the instrument panel. The display device 20 includes lighting units 21a to 21f. Each of the lighting parts 21a to 21f is associated with each of the steering switches 11a to 11f, and an operation state of the steering switch 11 is displayed. For example, when the steering switch 11e is operated, the lighting unit 11e is turned on, and the driver is visually informed that the steering switch 11e has been operated. Instead of mere lighting, sound such as a change in color and brightness, blinking, and a beep sound may be output.

  Therefore, when the steering switch 11 is operated, it is not necessary for the driver to move his / her line of sight from the front (distant) of the vehicle to the steering hole 10 (near) at hand in order to visually recognize the switch position / type. That is, the driver can easily understand the position of the switch being operated and other switches without directly viewing the steering switch 11 (so-called blind operation), improving the operability of the steering switch 11 and the driver's viewpoint. Movement can be reduced.

  By the way, when the operator touches the sensor electrode 35 of the capacitance sensor, as shown in FIG. 3, the detection voltage Vc fluctuates due to the change in capacitance (the Vc voltage waveform in the section A due to the contact with the sensor electrode 35). As a result, the output value (OUT voltage) from the sensor main body also changes (the OUT voltage value decreases in section A). The switch operation confirmation unit 36 determines whether or not the operator touches the sensor electrode 35 by detecting this change (that is, whether or not the switch is operated). As a condition for performing the determination, a contact determination threshold is set on the switch operation determination unit 36 side. When it is assumed that the operator touches the sensor electrode 35 and a change I occurs in the OUT voltage, and the OUT voltage drops like D, the presence / absence of the switch operation is determined because the contact determination threshold is set to the B position. Can be determined.

  However, if the contact determination threshold value B is set to a fixed value in order to determine the switch operation, whether or not the operator touches the sensor electrode 35 depending on glove wear, individual differences, and fingertip conditions (sweat and scratches). May not be able to be determined. For example, when a glove is not worn, the OUT voltage changes as D, but when a glove is worn, the OUT voltage changes as E. Therefore, when the glove is worn and the contact determination threshold is set to the position B, the change in the OUT voltage cannot be detected, and the switch operation cannot be confirmed. Similarly, the amount of change in capacitance due to touch by a person varies from person to person, so the OUT voltage may not drop to the contact determination threshold B.

  Therefore, the touch switch of the present invention is provided with a sub-contact detection sensor as a sub-detection unit that detects the contact of the operator at a position different from the contact detection sensor that detects the contact by the switch operation. In this embodiment, as shown in FIG. 1, the grip portion 14 of the steering wheel 10 is provided with sub-contact detection sensors 12 a and 12 b. A gripping portion that always contacts the left hand of the driver when the steering wheel 10 is gripped in a gripping posture in which the steering switches 11a, 11b, and 11c (contact detection sensors) of the left switch group can be operated by the left hand while the steering wheel 10 is gripped. 14 is preferably provided with a sub-contact detection sensor 12a, and the steering wheel 10 is held in a gripping posture in which the steering switches 11d, 11e, and 11f (contact detection sensors) of the right switch group can be operated with the right hand while the steering wheel 10 is gripped. It is desirable that the sub-contact detection sensor 12b is provided in the grip portion 14 that always contacts the right hand of the driver when gripped.

  The sub-contact detection sensors 12a and 12b detect the presence / absence of contact by utilizing changes in capacitance, pressing force, temperature, and the like caused by the touch of the driver, like the above-described contact detection sensors. . The contact detection sensor and the sub-contact detection sensors 12a and 12b use the same type of sensor. If a capacitance sensor is used as the contact detection sensor, the sub-contact detection sensors 12a and 12b also use capacitance sensors. If a temperature sensor is used as the contact detection sensor, the sub-contact detection sensors 12a and 12b also Adopt temperature sensor.

  The sub-contact detection sensors 12a and 12b and the contact detection sensor provided in the steering switch 11 sense contact independently of each other. Therefore, since the contact state of the driver detected by the sub-contact detection sensor 12 can be used to adjust the contact determination threshold value for determining the switch operation on the contact detection sensor side that detects the contact by the switch operation, It becomes possible to accurately detect the switch operation of the operator.

  That is, according to FIG. 3, when the OUT voltage is detected as E by the sub-contact detection sensor 12, the switch operation confirmation unit 36 sets the contact determination threshold from the position B to the change H as the condition correction unit. To the position of C.

  At this time, the correction by the switch operation determination unit 36 is performed only when contact is detected by the sub-contact detection sensor. As a result, the contact determination threshold value is corrected every time the driver grips the steering wheel 10. Therefore, sweating and changes in physical condition always change during driving, and the detected contact state changes accordingly (for example, the capacitance changes), so that the contact at that time corresponds to the change. The contact determination threshold value that is optimal for the state can be corrected.

  Further, the switch operation determination unit 36 may store the corrected contact determination threshold value in a volatile memory or a nonvolatile memory. As a result, the corrected contact determination threshold value can be maintained even if the driver temporarily removes his / her hand from the steering wheel 10.

  Therefore, the switch operation confirmation unit 36 adjusts the contact determination threshold value for confirming the switch operation by the sub-contact detection sensor 12 even when the switch operation is not confirmed even when the steering switch 11 is touched while wearing gloves. Therefore, the switch operation can be determined accurately.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, the switch operation may be confirmed only when contact is detected by the sub-contact detection sensor. Thereby, for example, when the driver's hand unintentionally touches the steering switch 11 other than the intentional contact by the driver who wants to operate the steering switch 11, or when the driver touches the steering wheel 10 appropriately. When it is not in a state of being held in a posture, it is possible to prevent the operation state from being displayed on the display device 20 or to prevent the in-vehicle device from operating.

  Further, for example, in FIG. 1, the finger for operating the steering switch 11 is drawn at a position where the finger is limited to the thumb, but the finger may be arranged at a position where it can be operated by a finger other than the thumb. For example, you may arrange | position on the back surface (front glass side) of the spoke part 13. FIG. Further, it may be arranged on a column lever such as a turn lever or a wiper lever, or a steering pad that enables a shift operation or a switch operation.

  Further, the installation location of the sub-contact detection sensor 12 may be a shift knob, an armrest, a door grip, an engine start switch, or a start key. It is provided in a place where the driver grips relatively frequently. In this case, since the hand is once away from the steering wheel 10, the output value from the sub-contact detection sensor 12 that has detected contact is temporarily held in a volatile memory or the like. Then, the switch operation confirmation unit 36 may correct the contact determination threshold as described above based on the held output value.

It is a figure which shows one Example at the time of applying the touch switch in this invention to the steering wheel of a vehicle. It is a figure which shows the touch switch using an electrostatic capacitance sensor as a representative example of a contact detection sensor. It is a voltage waveform diagram of a contact detection sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Steering wheel 11 Steering switch 12 Contact detection sensor 13 Spoke part 14 Gripping part 20 Indicator 21 Lighting part 30 Sensor circuit part 35 Sensor electrode 36 Switch operation confirmation part

Claims (8)

Having detection means for detecting operator contact;
When the output value of the detection unit that varies depending on the contact state satisfies a predetermined condition, the touch switch determines the contact detected by the detection unit as the switch operation of the operator,
Sub-detecting means for detecting contact of an operator installed at a different position from the detecting means;
A touch switch comprising: condition correcting means for correcting the predetermined condition in accordance with an output value of the sub-detecting means that varies depending on a contact state. The predetermined condition is a contact determination threshold value,
The touch switch according to claim 1, wherein the condition correction unit sets the contact determination threshold value between an output value of the sub detection unit in a non-contact state and an output value of the sub detection unit in a contact state.   The touch switch according to claim 1, wherein the detection unit and the sub detection unit detect contact based on a change in capacitance.   The touch switch according to claim 1, wherein the detection means is attached to a steering wheel of a vehicle.   The touch switch according to claim 4, wherein the detection means is located in a spoke portion of the steering wheel.   The touch switch according to claim 4 or 5, wherein the sub detection means is located at a grip portion of the steering wheel.   The touch switch according to claim 6, wherein the correction by the condition correction unit is performed only when contact is detected by the sub detection unit.   A vehicle steering wheel comprising the touch switch according to claim 1.

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