JP2018091810A - Electrostatic sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic sensor capable of detecting position of a detection object with fewer number of channel.SOLUTION: The electrostatic sensor includes: a first electrode 21 and a second electrode 22 each of which has a shape described below; and a capacity comparison detector. The first electrode 21 has a shape that the size gradually gets smaller toward the rear side. The second electrode 22 has a shape the size gradually gets smaller toward the front side. The capacity comparison detector detects a front-rear direction of a detection object based on comparison of capacitance changes in the first electrode 21 and the second electrode 22.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an electrostatic sensor.

For example, an electrostatic sensor that detects whether or not a detection target such as a human body is in proximity is known through a change in capacitance.
The electrostatic sensor disclosed in Patent Document 1 employs a multi-channel method that can detect the position of a detection target using a large number of electrodes having different oscillation frequencies.

JP-A-5-264623

The electrostatic sensor that employs the multi-channel method as in Patent Document 1 requires a control unit and a circuit with high processing capability.
An object of the present invention is to provide an electrostatic sensor that detects the position of a detection target with a smaller number of channels.

  In order to solve the above problem, the electrostatic sensor has a first electrode that decreases in size toward one of the preset setting directions, and decreases in size toward the other of the setting directions, and in the setting direction. The position of the detection target in the setting direction based on the second electrode arranged in parallel to the first electrode, and the capacitance of the first electrode and the second electrode that change when the detection target approaches. The gist of the present invention is to include a detection unit that detects

  It is well known that the capacitance of an electrode changes when a conductor such as a hand approaches the electrode. It is also well known to detect changes in the capacitance of each of the first electrode and the second electrode as the capacitance of the electrode changes.

According to this configuration, the size of the first electrode decreases in the setting direction. In addition, the size of the second electrode increases in the setting direction.
The amount of change in capacitance is in accordance with the following (Equation 1). That is, since it is proportional to the facing area between the electrode and the conductor such as the user's hand, when the electrode and the conductor face each other, the amount of change in capacitance is unambiguous depending on the position of the conductor with respect to the electrode. It is decided. Therefore, the detection part can detect suitably the position of the conductor with respect to an electrode based on the variation | change_quantity of an electrostatic capacitance.

C = ε ₀ ε _r S / d (Formula 1)
C: Capacitance, ε: Dielectric constant, 0: Electrode, r: Conductor, S: Opposing area, d: Distance Thus, according to this configuration, only two electrodes (two channels) are used, that is, The position of the detection target can be accurately detected with a smaller number of channels than before.

  In the above configuration, the first electrode and the second electrode are formed to have the same dimension in the setting direction and the orthogonal direction, and the first electrode has a shape that gradually becomes sharper toward one of the setting directions. The second electrode has a shape that gradually becomes sharper toward the other of the setting directions, and the first electrode and the second electrode overlap when viewed from the setting direction and the orthogonal direction. It is preferable that they are arranged as described above.

  According to this configuration, the first electrode and the second electrode jointly form a rectangular shape when viewed from a direction orthogonal to both the setting direction and the orthogonal direction. Thereby, the user can easily grasp which position of the first electrode and the second electrode he / she has touched.

  The said structure WHEREIN: The said 2nd electrode has an insertion part of the shape which becomes sharp as it goes to one side of the said setting direction, The said 1st electrode has the shape which reversed the said insertion part in the said setting direction. It is preferable to have an insertion part.

  According to this configuration, the second electrode is located on both sides of the first electrode in the orthogonal direction. For this reason, if the hand is placed so as to face the first electrode, it also faces the second electrode. That is, even if the hand is displaced in the orthogonal direction, the hand is likely to face the first electrode and the second electrode. For this reason, the usability of the electrostatic sensor is good for the user.

  The said structure WHEREIN: It is preferable that the said 1st electrode and the said 2nd electrode are provided with two or more so that it may respectively become the same number, and these are arranged in parallel so that it may become alternate in the said setting direction.

  In this configuration, the first electrode whose size decreases stepwise toward one of the setting directions and the second electrode whose size decreases stepwise toward the other of the setting directions are arranged side by side in a staggered manner. This is a simple configuration. Even if it comprises in this way, when the electrode and a conductor are made to oppose, the change of each electrostatic capacitance of a 1st electrode and a 2nd electrode is uniquely determined according to the position of the conductor with respect to an electrode. Therefore, the detection part can detect suitably the position of the conductor with respect to an electrode based on an electrostatic capacitance change amount.

  The electrostatic sensor of the present invention can detect the position of the detection target with a smaller number of channels.

The side view which shows a vehicle side part. The block diagram which shows the electrical constitution of a sliding door opening / closing apparatus. The front view of a 1st electrode and a 2nd electrode. The graph which shows the relationship between the position of the hand dressed on the 1st electrode and the 2nd electrode, and an electrostatic capacitance change amount. The block diagram which shows the electrical constitution of the sliding door opening / closing apparatus which employ | adopted the electrostatic sensor of another form. The front view which shows another example of a 1st electrode and a 2nd electrode. FIG. 7 is a graph showing the relationship between the position of a hand dressed on the first electrode and the second electrode and the amount of change in capacitance when another example shown in FIG. The front view which shows another example of a 1st electrode and a 2nd electrode.

Hereinafter, an embodiment of a sliding door opening and closing device employing an electrostatic sensor will be described with reference to the drawings.
As shown in FIG. 1, the vehicle 1 includes a slide door opening / closing device 10 that opens and closes the slide door opening 3 when a slide door 2 provided on a side portion of the vehicle is displaced in the front-rear direction.

  The sliding door opening / closing device 10 includes an electrostatic sensor 11 provided in a portion separating the front seat opening 4 and the sliding door opening 3, so-called B pillar 5. The electrostatic sensor 11 is attached to the B pillar 5 so as to expose the first electrode 21 and the second electrode 22 constituting the sensor.

  As shown in FIGS. 2 and 3, the electrostatic sensor 11 includes a first electrode 21, a second electrode 22, and a capacitance comparison detection unit 26, and each of these components is provided on a substrate (not shown). The capacity comparison / detection unit 26 is electrically connected to the in-vehicle ECU 12 constituting the slide door opening / closing device 10.

  The first electrode 21 is an isosceles triangular electrode having a side 31 extending in the vertical direction as a base 31 and having equal sides 32 extending rearward from both ends of the base 31. The height of the first electrode 21 relative to the base 31 (the length in the vehicle front-rear direction) is set to be longer than the length of the base 31. The front-rear direction corresponds to the setting direction, and the vertical direction corresponds to the orthogonal direction. Further, as described above, the first electrode 21 has a shape that gradually becomes sharper toward the rear, and functions as an insertion portion.

The second electrode 22 includes an upper electrode 41 and a lower electrode 42.
The upper electrode 41 includes a hypotenuse 43 extending parallel to the upper equilateral side 32 of the first electrode 21, a long adjacent side 44 extending rearward from the upper end of the hypotenuse 43, and a rear end of the long adjacent side 44. This is a portion of a substantially right triangle having a short adjacent side 45 extending downward from. The length of the long adjacent side 44 is set substantially equal to the height of the first electrode 21, and the length of the short adjacent side 45 is set substantially equal to the half length of the bottom 31 of the first electrode 21.

  The lower electrode 42 includes a hypotenuse 46 extending parallel to the lower equilateral side 32 of the first electrode 21, a long adjacent side 47 extending rearward from the lower end of the hypotenuse 46, and a rear side of the long adjacent side 47. It is a portion of a substantially right triangle having a short adjacent side 48 extending upward from the side end. The length of the long adjacent side 47 is set substantially equal to the height of the first electrode 21, and the length of the short adjacent side 48 is set to be approximately equal to the half length of the bottom 31 of the first electrode 21.

The upper electrode 41 and the lower electrode 42 are continuous with each other such that the short adjacent sides 45 and 48 form one side in the vertical direction.
An insulating material 49 is interposed between the first electrode 21 and the second electrode 22 between the equal side 32 of the first electrode 21 and the oblique sides 43 and 46 of the second electrode 22, respectively. ing.

With the above configuration, the first electrode 21 and the second electrode 22 are formed into a substantially rectangular shape that is long in the front-rear direction and short in the vertical direction.
In addition, in the substantially rectangular shape jointly configured by the first electrode 21 and the second electrode 22, the length in the vertical direction is sufficiently shorter than the length from a general adult wrist to the fingertip, and the length in the front-rear direction is Each dimension is set so as to be sufficiently longer than the width direction length of a general adult palm. Further, the second electrode 22 functions as an insertion portion in which the shape surrounded by the oblique sides 43 and 46 in the vertical direction gradually becomes sharper toward the rear. The shape that functions as the insertion portion is obtained by inverting the shape that functions as the insertion portion of the first electrode 21 in the front-rear direction.

The first electrode 21 and the second electrode 22 are electrically connected to the capacitance comparison detection unit 26, respectively.
The capacitance comparison detection unit 26 changes depending on the capacitance change amount of the first electrode 21 that changes due to the approach and separation of the conductor to the first electrode 21 and the approach and separation of the conductor to the second electrode 22. The capacitance change amount of the second electrode 22 is compared. The capacitance comparison detection unit 26 determines the position of the conductor with respect to the first electrode 21 and the second electrode 22 according to the ratio between the capacitance change amount of the first electrode 21 and the capacitance change amount of the second electrode 22. To detect. And the capacity | capacitance comparison detection part 26 produces | generates the positional information signal containing the positional information which is a detection result.

  The in-vehicle ECU 12 controls various in-vehicle devices, and controls the driving of a motor (not shown) according to the position information signal. When the motor (not shown) is driven, the slide door 2 (see FIG. 1) is displaced in the front-rear direction. Thereby, the sliding door opening 3 is opened and closed.

  Next, the operation and effect of the electrostatic sensor configured as described above will be described. As shown in FIG. 3, the vertical length of the first electrode 21 is defined as La, and the vertical length of the second electrode 22 is defined as Lb.

  As shown in FIG. 3, according to the electrostatic sensor 11 of this configuration, the vertical length La of the first electrode 21 is gradually shortened toward the rear, and the vertical length Lb of the second electrode 22 is rearward. The first electrode 21 has an insertion portion, and the second electrode 22 has an insertion portion so as to gradually become longer as it goes toward.

  Here, in the substantially rectangular shape configured by the first electrode 21 and the second electrode 22, the length in the vertical direction is sufficiently shorter than the length from the general adult wrist to the fingertip, and the length in the front-rear direction. Is sufficiently longer than the width of a typical adult palm.

  Therefore, the facing area between the first electrode 21 and the hand is proportional to the vertical length La of the first electrode 21 corresponding to the position in the front-rear direction of the hand, and the facing area between the second electrode 22 and the hand is It is proportional to the vertical length Lb of the second electrode 22 corresponding to the front-rear direction position.

  As a result, as shown in FIG. 4, as the hand is displaced rearward, the amount of change in capacitance at the first electrode 21 gradually decreases and the amount of change in capacitance at the second electrode 22 gradually increases. To do.

  Here, the amount of change in capacitance is in accordance with the following (Equation 1). That is, since it is proportional to the facing area between the electrode and the conductor such as the user's hand, when the electrode and the conductor face each other, the amount of change in capacitance is unambiguous depending on the position of the conductor with respect to the electrode. It is decided. Therefore, the detection part can detect suitably the position of the conductor with respect to an electrode based on the variation | change_quantity of an electrostatic capacitance.

C = ε ₀ ε _r S / d (Formula 1)
C: electrostatic capacity, ε: dielectric constant, 0: electrode, r: conductor, S: facing area, d: distance Therefore, each electrode proportional to the facing area of the first electrode 21 and the second electrode 22 with the hand The amount of change in capacitance is uniquely determined according to the position in the front-rear direction of the hand. Therefore, the capacitance comparison detection unit 26 can detect the position in the front-rear direction with respect to the first electrode 21 and the second electrode 22 of the hand based on the amount of change in capacitance of the first electrode 21 and the second electrode 22. And the capacity | capacitance comparison detection part 26 can produce | generate the positional information signal according to the front-back direction position of a hand.

  Thereby, the vehicle-mounted ECU 12 can control the drive of a motor (not shown) so as to correspond to the position in the front-rear direction of the hand with respect to the first electrode 21 and the second electrode 22. Therefore, the slide door 2 can be displaced to a position corresponding to the position in the front-rear direction of the hand.

That is, the vehicle user can adjust the sliding door opening 3 to a desired opening degree only by adjusting the position in the front-rear direction of the hand with respect to the first electrode 21 and the second electrode 22.
The in-vehicle ECU 12 controls the driving of a motor (not shown) so as to correspond to the position in the front-rear direction of the hand with respect to the first electrode 21 and the second electrode 22, but the front and rear of the hand with respect to the first electrode 21 and the second electrode 22. You may control the drive of the motor which is not illustrated so that it may respond to the time change of a direction position.

If comprised in this way, when a vehicle user performs what is called a motion operation which displaces the hand held up to the 1st electrode 21 and the 2nd electrode 22 forward or back, in this case, the slide door 2 will be 1st electrode When a motion operation is performed to displace the hand held over 21 and the second electrode 22 forward or backward, the slide door opening 3 can be displaced to the forefront or to the end. That is, the vehicle user can open and close the slide door 2 by performing a motion operation.

  As described above, the electrostatic sensor 11 of this configuration uses only the two channels of the first electrode 21 and the second electrode 22, that is, the number of channels is smaller than that in the conventional case, and the displacement of the hand that is the detection target is reduced. Can be detected. Then, the slide door opening / closing device 10 employing the electrostatic sensor 11 displaces the slide door 2 according to the position of the hand held by the electrostatic sensor 11, that is, to a position desired by the vehicle user. Can be made.

  Moreover, when the electrostatic sensor 11 of this structure is seen from the vehicle width direction orthogonal to the vehicle longitudinal direction and the vehicle vertical direction, the first electrode 21 and the second electrode 22 jointly form a rectangular shape. This makes it easy for the user to grasp which position of the first electrode 21 and the second electrode 22 the user has touched.

  Furthermore, in the electrostatic sensor 11 of this configuration, since the first electrode 21 is accommodated in the recess of the second electrode 22, the second electrode 22 is located on both sides of the first electrode 21 in the vertical direction. For this reason, if the hand is placed so as to face the first electrode 21, the hand also faces the second electrode 22. That is, even if the hand is displaced in the vertical direction, the first electrode 21 and the second electrode 22 are likely to face each other. For this reason, the usability of the electrostatic sensor 11 is good for the user.

In addition, you may change the said embodiment as follows.
The electrostatic sensor 11 of the above embodiment has a configuration in which the capacitance comparison detection unit 26 detects the amount of change in capacitance in the first electrode 21 and the second electrode 22, but may be configured as follows. .

That is, as shown in FIG. 5, the electrostatic sensor 50 includes a first electrode 21, a second electrode 22, a first resonance circuit 51, a second resonance circuit 52, an oscillation circuit 53, and a detection unit 54.
The first electrode 21 is electrically connected to the oscillation circuit 53 via the first resonance circuit 51, and the second electrode 22 is electrically connected to the oscillation circuit 53 via the second resonance circuit 52. The first resonance circuit 51 and the second resonance circuit 52 are also electrically connected to the detection unit 54.

The first resonance circuit 51 is supplied with an oscillation signal from the oscillation circuit 53 and generates a resonance signal having a preset resonance frequency.
When the oscillation signal is supplied from the oscillation circuit 53, the second resonance circuit 52 generates a resonance signal having a resonance frequency set in advance to a value different from the resonance frequency of the first resonance circuit 51.

The first resonance circuit 51 generates a resonance frequency corresponding to the amount of change in the capacitance of the first electrode 21 that changes as the conductor approaches and separates from the first electrode 21.
In addition, the second resonance circuit 52 generates a resonance frequency corresponding to the amount of change in the capacitance of the second electrode 22 that changes as the conductor approaches and separates from the second electrode 22.

  The detection unit 54 detects the position of the conductor with respect to the first electrode 21 and the second electrode 22 in accordance with the resonance signals generated by the first resonance circuit 51 and the second resonance circuit 52, respectively. Then, a position information signal including position information as a detection result is generated.

Even if the electrostatic sensor 50 configured as described above is employed, the same effect as in the above-described embodiment can be obtained.
-In the said other example, you may change the 1st electrode 21 and the 2nd electrode 22 as follows.

  That is, as shown in FIG. 6, the first electrodes 61 and 62 connected to the first resonance circuit 51 (see FIG. 5) and the second electrodes 63 and 62 connected to the second resonance circuit 52 (see FIG. 5). 64 is adopted.

  The first electrodes 61 and 62 and the second electrodes 63 and 64 have the same vertical dimension. The front-rear dimension of the first electrode 61 and the second electrode 63 is L1, and the front-rear dimension of the first electrode 62 and the second electrode 64 is L2, which is shorter than the front-rear dimension of the first electrode 61 and the second electrode 63, respectively. Is set.

  These electrodes are arranged in the order of the first electrode 61, the second electrode 64, the first electrode 62, and the second electrode 63 from the front to the rear. These electrodes are separated from each other.

  That is, the first electrodes 61 and 62 and the second electrodes 63 and 64 are arranged side by side so as to be alternated in the front-rear direction. The first electrodes 61 and 62 are arranged side by side so that the size decreases stepwise toward the rear, and the second electrodes 63 and 64 decrease in size stepwise toward the front.

  Even in this configuration, as shown in FIG. 7, when a conductor such as a hand is opposed to each electrode, the first resonance circuit 51 and the second resonance are caused by the amount of change in capacitance. The resonance frequency generated by each of the circuits 52 is uniquely determined according to the position of the conductor with respect to each electrode. Therefore, the detection unit 54 can suitably detect the position of the conductor with respect to each electrode based on the resonance signal.

In addition, in this another example, although the 1st electrode and the 2nd electrode were two each, three or more may be sufficient. However, the first electrode and the second electrode are the same number.
In the above embodiment, the first electrode 21 has the equal side 32 so that the length in the vertical direction gradually decreases. However, the length in the vertical direction of the first side 21 is gradually reduced. It may be changed to a staircase. Moreover, you may change the oblique sides 43 and 46 of the 2nd electrode 22 to step shape so that it may respond | correspond. Even when configured in this manner, the same effects as those of the above-described embodiment can be obtained.

  In the above embodiment, the first electrode 21 and the second electrode 22 may be changed as follows. That is, as shown in FIG. 8, the first electrode 81 and the second electrode 82 may be provided so as to be congruent right-angled triangles, and their hypotenuses face each other. Even in this configuration, the amount of change in capacitance at each electrode is uniquely determined according to the position of the conductor with respect to each electrode. Therefore, the capacitance comparison detection unit 26 can preferably detect the position of the conductor with respect to each electrode based on the capacitance change amount.

  In the above embodiment, the insulating material 49 is provided between the first electrode 21 and the second electrode 22, and the insulating material 83 is provided between the oblique sides of the first electrode 81 and the second electrode 82 in the other example. These insulating materials 49 and 83 are not essential components. It is unnecessary if insulation between the first electrode 21 and the second electrode 22 and between the first electrode 81 and the second electrode 82 are ensured.

  In the above embodiment, the electrostatic sensor 11, more precisely, the first electrode 21 and the second electrode 22 are provided on the B pillar, but the positions provided are not limited thereto. It may be attached to the slide door 2 or a window. Moreover, when the step is provided in the vehicle lower part, you may attach to the step.

In the above embodiment, the object to be opened and closed is not limited to the slide door 2. For example, a back door, a window, a sunroof, or the like may be opened / closed.
The electrostatic sensor is preferably provided in the vicinity of the object to be opened and closed.

Next, the technical idea conceived from the embodiment and the other examples will be described.
(A) A vehicle opening / closing body device for opening / closing an opening / closing object based on the detection result of the electrostatic sensor having the above-described configuration.

  (B) A first resonance circuit that generates a resonance signal of the first resonance frequency by being connected to the oscillation circuit and supplied with an oscillation signal, and a resonance signal of a second resonance frequency different from the first resonance frequency. A second resonance circuit; a first electrode connected to the first resonance circuit; the first electrode having a size that decreases toward one of the preset setting directions; and the second resonance circuit connected to the second resonance circuit; A second electrode that decreases in size toward the other side, and the first electrode and the second electrode that are connected to each of the first resonance circuit and the second resonance circuit and are arranged in parallel based on the resonance signal of each resonance frequency An electrostatic sensor comprising: a detection unit that detects a position of a detection target in a direction.

DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Slide door (opening-closing object), 3 ... Slide door opening part, 4 ... Front seat opening part, 5 ... B pillar, 10 ... Slide door opening / closing apparatus 11, 50 ... Electrostatic sensor, 12 ... In-vehicle ECU, 21, 61, 62, 81 ... first electrode, 22, 63, 64, 82 ... second electrode, 26 ... detector, 31 ... bottom, 32 ... equilateral, 41 ... upper electrode, 42 ... lower electrode, 43, 46 ... oblique side, 44, 47 ... long adjacent side, 45, 48 ... short adjacent side, 49, 83 ... insulating material, 51 ... first resonance circuit, 52 ... second resonance circuit, 53 ... oscillation circuit, 54 ... Detection unit.

Claims (4)

A first electrode that decreases in size toward one of the preset setting directions;
A second electrode arranged in parallel with the first electrode in the setting direction and having a size that decreases toward the other of the setting direction;
An electrostatic sensor comprising: a detection unit configured to detect a position of the detection target in the setting direction based on capacitances of the first electrode and the second electrode that change when the detection target approaches. The electrostatic sensor according to claim 1,
The first electrode and the second electrode are formed with equal dimensions in the setting direction and the orthogonal direction,
The first electrode has a shape that gradually becomes sharper toward one of the setting directions,
The second electrode has a shape that gradually becomes sharper toward the other of the setting directions,
The first electrode and the second electrode are electrostatic sensors arranged so as to overlap when viewed from the setting direction and the orthogonal direction. The electrostatic sensor according to claim 2,
The second electrode has an insertion portion having a shape that becomes sharper toward one of the setting directions,
The first electrode is an electrostatic sensor having an insertion portion having a shape obtained by inverting the insertion portion in the setting direction. The electrostatic sensor according to claim 1,
An electrostatic sensor in which a plurality of the first electrodes and the second electrodes are provided in the same number, and these are arranged in parallel so as to be alternated in the setting direction.

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