JP2000249773A - Seating sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seating sensor for grasping weight and a posture of a seated person with less influence due to environmental temperature fluctuation on reproducibility. SOLUTION: In a seating sensor mounted to a seat, a variable electrostatic capacity unit C1 is constructed of two electrodes D1, D2 differentiated from each other in potential. When electrostatic capacity of the variable electrostatic capacity unit C1 fluctuating by influence from a human body seated on the seat is converted into an electric signal, it is detected that the person is seated on the seat. The electrodes are printed on a resin film and covered with a protective film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor (hereinafter, referred to as a seating sensor) mounted on a seat portion or a backrest of a seat for grasping the weight and posture of a seated person.

[0002]

2. Description of the Related Art As a seating sensor, for example, FIG.
As shown in FIG. 18, the seating sensor includes a plurality of electrodes covered with a pressure-sensitive ink 90.
The two resin films 9, 9 having 91
91, 91 are arranged so as to face each other.

In this seating sensor, when the weight is added, the contact resistance between the opposing pressure-sensitive inks 90, 90 changes in accordance with the weight, so that the weight, the weight distribution and the posture of the seated person are detected. Is possible.

However, the pressure-sensitive ink 90 used in the seating sensor has a problem that the reproducibility varies because the resistance greatly changes due to a change in environmental temperature.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a seating sensor which has a small influence on reproducibility due to a change in environmental temperature and can grasp the weight and posture of a seated person.

[0006]

Means for Solving the Problems (Invention of Claim 1)
According to the present invention, in a seating sensor mounted on a seat, a variable capacitance section is constituted by two electrodes provided with a potential difference, and a static capacitance of the variable capacitance section that changes under the influence of a human body sitting on the seat. By converting the electric capacity into an electric signal, it is detected that a person is sitting on the seat. According to a second aspect of the present invention, there is provided a seating sensor mounted on a seat, wherein a plurality of variable capacitance portions are formed by providing a potential difference between a common electrode and a plurality of independent electrodes, and the variable static capacitance portion is formed. The capacitance unit is arranged at a predetermined position of a seat or a backrest of a seat, and converts the capacitance of the variable capacitance unit, which changes due to the influence of a human body sitting on the seat, into an electric signal. Thus, the weight and posture of the seated person can be grasped. (Invention of Claim 3) According to the present invention, as to the invention of Claim 1 or 2, the electrode is printed on a resin film and covered with a protective film. (Invention of claim 4) The present invention relates to the invention of any one of claims 1 to 3, wherein an elastic body is laminated directly on an electrode or through a protective film and a conductor is formed on the elastic body. Laminated. According to a fifth aspect of the present invention, in a seating sensor to be mounted on a seat, a variable capacitance is provided by disposing a conductor facing an electrode via an elastic body and providing a potential difference between the electrode and the conductor. The capacitance of the variable capacitance portion, which changes when the electrode and the conductor approach each other due to the weight of the human body sitting on the seat, is converted into an electric signal, whereby a person is seated on the seat. Is to be detected. According to a sixth aspect of the present invention, in the fifth aspect of the present invention, a plurality of variable capacitance portions are formed by providing a plurality of electrodes, and the variable capacitance portions are provided in a seat portion or a backrest portion of a seat. At a predetermined position, so that the weight and posture of the occupant can be grasped. (Invention of Claim 7) In the present invention, according to the invention of Claim 5 or 6, the electrodes are formed by printing on a resin film.

[0007] The seating sensor of the present invention is described as follows.
This will be described in detail in the following embodiments.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. [Basic Structure 1, 2, 3 of Seating Sensor] (1) Basic Structure 1 As shown in FIG. 1 and FIG.
The electrodes D1 and D2 (covered with a protective film HM) are arranged at a slight interval on an insulating film 1 such as a film, and a voltage is applied between the electrodes D1 and D2 to change the variable capacitance portion C1. Is formed. Since the capacitance of the variable capacitance portion C1 is affected by the dielectric constant of the surroundings, when the human body M or an object comes close to between the electrodes D1 and D2 as shown in FIG.
The dielectric constant in the vicinity between 1 and D2 changes, and as a result, the capacitance of the variable capacitance unit C1 changes.

Here, the seating sensor S includes electrodes D1 and D2.
The longer the opposing length, the larger the variable capacitance part C1
Of the variable capacitance unit C1 due to a change in the surrounding dielectric constant also increases. Therefore, as shown in FIG. 4, if the distance between the electrodes D1 and D2 is increased, the sensitivity of the seating sensor S can be increased. (2) Basic structure 2 In the above basic structure 1, the dielectric constant is affected by the difference in the surrounding objects between the electrodes D1 and D2, but depending on the application, the object can be detected without being affected by the material difference of the objects. May be preferred.

In such a case, as shown in FIG.
A cushioning material EB having elasticity may be overlaid on the seating sensor S indicated by, and a conductor DT made of metal or conductive rubber having an electrostatic shielding function may be further overlaid. Then the electrode
The capacitance of the variable capacitance portion C1 between D1 and D2 is mainly affected by the dielectric constant of the cushion material EB. (3) Basic Structure 3 FIG. 6 is an example in which the seating sensor S showing the detection principle 3 is modified, and the structure is the same as that of FIG.
Is grounded to GND (0 V). That is, in the seating sensor S, the variable capacitance portion C2 is formed by the electrode D1 and the conductor DT.

In this seating sensor, the capacitance of the variable capacitance section C2 is electrostatically shielded by the conductor DT, so that the influence of the dielectric constant of the substance between the conductor DT and the human body M (object). And is substantially determined by the magnitude of the dielectric constant of the cushion material EB, the area of the electrode D1, and the distance between the cushion material EB and the electrode D1.

Now, when a person presses the conductor DT by a force such as weight, the distance between the conductor DT and the electrode D1 decreases, and the capacitance of the variable capacitance portion C2 increases. (4) If C / V conversion (capacitance / voltage conversion) is performed as shown in FIG. 7 using the basic structures 1, 2, and 3, information on the weight of a passenger such as an automobile can be detected as an electric signal. .

As shown in FIGS. 8 and 9, the capacitance of the two variable capacitance units C1 and C2 or the capacitance of the variable capacitance C1 and the capacitance of the fixed capacitance unit CF are compared. The difference may be converted into an appropriate electric signal.

Further, the C / V conversion (capacitance / voltage conversion) circuit shown in FIGS. 7 to 9 may be replaced by a C / F conversion (capacitance / frequency conversion) or a C / I conversion (capacitance / voltage conversion). / Current conversion)
Circuit. [Automotive Occupant Weight Detection System] (5) FIG. 10 shows an example in which a seating sensor S using the basic structures 1 and 2 is mounted on the seat portion ST1 and the backrest portion ST2 of the vehicle seat ST, and FIG. The seating sensor S is shown.

As shown in FIG. 11, the seating sensor S is a PE sensor.
The electrodes D1, D2, D3, D4 and the common electrode D arranged at 90 ° intervals are printed on an insulating film 1 such as a T film, and a voltage is applied to the electrodes D1, D2, D3, D4. With the common electrode D grounded, the variable capacitance units C1, C2, C3,
C4 (C11, C12, C13, C14) is formed. The capacitances of the variable capacitance units C1, C2, C3, and C4 (C11, C12, C13, and C14) are calculated by the circuits shown in FIGS. ).

Here, if the electric signal corresponding to the capacitance of the variable capacitance section C1 is larger than the electric signal corresponding to the capacitance of the variable capacitance section C2, the occupant can move from the variable capacitance section C1. You can see that he is sitting at In addition, the variable capacitance C1, C
If there is a change in the electric signals corresponding to the capacitances of 2, 2, C3, C4 and any of the electric signals corresponding to the capacitances of the variable capacitance units C11, C12, C13, C14, the occupant is notified. It can be seen that the user is sitting in contact with the backrest ST2. (6) FIG. 12 and FIG. 13 show an example in which the seating sensor S using the structure of the basic structures 1 and 2 is mounted on the seat portion ST1 and the backrest portion ST2 of the automobile seat ST.

In the seating sensor S shown in FIG. 12, electrodes DX1... DXn, DY1... DYn and a common electrode D are printed on the insulating film 1, and the electrodes DX1.
A voltage is applied to DY1... DYn and the common electrode D is grounded so that 2 × n variable capacitance units are arranged in a line.

The seating sensor S shown in FIG. 13 includes an electrode DX11... DX1n, an electrode DX21... DX2n, an electrode DY11... DY1n, an electrode DY21.
DX11 ... DX1n / electrode DX
21 ... DX2n / electrode DY11 ... DY1n / electrode DY21 ... DY
2n is applied and a common electrode D is grounded.
The variable capacitance units are formed so as to be arranged in two rows on the left and right. Therefore, it can be understood how much the weight of the occupant rests on the left and right in the seat portion ST1 and the backrest portion ST2. That is, the weight and posture of the occupant can be grasped. (7) FIG. 14 shows a seating sensor S using the structure of the above-described basic structure 3 (shown in FIG. 6) as a seat ST of an automobile seat ST.
1 shows an example of mounting on a backrest part ST2.

This seating sensor S basically has a basic structure 3
Configuration, but a large number of electrodes DX1
..DXn to the backrest part ST2 of a large number of electrodes DY1 ... DY
n are arranged. Therefore,
In this seating sensor S, the conductor DT and the electrodes DX1.
/ Electrode DY1 ... DYn for seat ST1 and backrest
A large number of variable capacitances, each of which is n, are formed in ST2, and the posture of the occupant can be grasped.

Note that the seating sensor S shown in FIG.
The electrodes DX1 ... DXn / electrodes DY1 ... DYn are divided into left and right electrodes DX11 ... DX1n / electrodes DX21 ... DX2n
/ Electrodes DY11 ... DY1n / electrodes DY21 ... DY2n
In this manner, it is possible to determine the ratio of the weight of the occupant on the left and right sides of the seat portion ST1 and the backrest portion ST2. (8) Next, all of the above-described variable capacitance units (the symbols are C
FIG. 16 shows a basic circuit for converting a change in the capacitance of the first embodiment into a change in the voltage output. In FIG. 16, symbols R1, R2, and R3 are fixed resistors, symbol IC1 is an EX-OR logic IC, and symbol CF.
Is a fixed capacitor, and a low-pass filter is configured by the resistor R3 and the fixed capacitor CF. The output is amplified as necessary, and input to a microcomputer or the like to perform calculations,
A signal according to the purpose can be output. (9) Since all the seating sensors described above do not use a material whose resistance greatly changes due to an environmental temperature change as in the prior art, it is clear that there is no large variation in reproducibility.

[0021]

Since the present invention has the above configuration, the following effects are obtained.

As is clear from the description in the section of the embodiment of the present invention, a seating sensor which has little influence on reproducibility due to a change in environmental temperature and can grasp the weight and posture of a seated person can be provided.

[Brief description of the drawings]

FIG. 1 is a plan view of a seating sensor having a basic structure 1 according to the present invention.

FIG. 2 is a sectional view of a seating sensor having a basic structure 1 according to the present invention.

FIG. 3 is a cross-sectional view showing a state in which a human body approaches a seating sensor of the basic structure 1.

FIG. 4 is a plan view showing a modification of the basic structure 1.

FIG. 5 is a sectional view of a seating sensor having a basic structure 2 according to the present invention.

FIG. 6 is a sectional view of a seating sensor having a basic structure 3 according to the present invention.

FIG. 7 shows the capacitance /
FIG. 3 is a voltage conversion circuit diagram.

FIG. 8 shows the capacitance /
FIG. 3 is a voltage conversion circuit diagram.

FIG. 9 shows the capacitance /
FIG. 3 is a voltage conversion circuit diagram.

FIG. 10 is a perspective view showing a state where a seating sensor using the basic structures 1 and 2 of the present invention is incorporated in a seat.

11 is a plan view of a seating sensor incorporated in the seat shown in FIG.

FIG. 12 is a plan view of another embodiment of a seating sensor using the basic structures 1 and 2 of the present invention.

FIG. 13 is a plan view of a seating sensor of another embodiment using the basic structures 1 and 2 of the present invention.

FIG. 14 is a perspective view showing a state in which a seating sensor using the basic structure 3 of the present invention is incorporated in a seat.

FIG. 15 is a perspective view showing a state in which a seating sensor of another embodiment utilizing the basic structure 3 of the present invention is incorporated in a seat.

FIG. 16 shows the capacitance /
FIG. 4 is a diagram illustrating a specific example of a voltage conversion circuit.

FIG. 17 is a plan view of a prior art seating sensor.

FIG. 18 is a cross-sectional view of a prior art seating sensor.

[Explanation of symbols]

 ST Seat ST1 Seat ST2 Backrest D Common electrode D1 Electrode D2 Electrode DT Conductor C1 Variable capacitance part C2 Variable capacitance part HM Protective film EB Elastic body 1 Film

Continued on the front page (72) Inventor Kazuhiro Okada 4-24-1 Sakuragicho, Omiya-shi, Saitama 4th floor, Tsuzuki Building F-term (reference) 2F063 AA25 AA37 AA49 AA50 BA29 BA30 CA40 DA02 DD07 HA02 HA04 HA10 HA14 HA18

Claims (7)

[Claims] 1. A seating sensor mounted on a seat,
A variable capacitance section is constituted by two electrodes provided with a potential difference, and the capacitance of the variable capacitance section, which changes due to the influence of a human body sitting on the seat, is converted into an electric signal, so that A seating sensor characterized by detecting that a person is seated. 2. A seating sensor mounted on a seat,
By providing a potential difference between a common electrode and a plurality of independent electrodes to form a plurality of variable capacitance portions, the variable capacitance portions are arranged at predetermined positions of a seat portion and a backrest portion of a seat. The seating is characterized in that the weight of the occupant and the posture of the occupant can be grasped by converting the capacitance of the variable capacitance section, which changes due to the influence of the human body sitting on the seat, into an electric signal. Sensor. 3. The seating sensor according to claim 1, wherein the electrodes are printed on a resin film and covered with a protective film. 4. The seat according to claim 1, wherein an elastic body is laminated on the electrode directly or via a protective film, and a conductor is laminated on the elastic body. Sensor. 5. A seating sensor mounted on a seat,
A conductor is arranged opposite to an electrode via an elastic body, and a potential difference is provided between the electrode and the conductor to form a variable capacitance portion.The electrode and the conductor approach each other due to the weight of a human body sitting on a seat. The capacitance of the variable capacitance portion, which changes according to the following, is converted into an electric signal, thereby detecting that a person is sitting on the seat. 6. A plurality of variable capacitance portions are formed by providing a plurality of electrodes, and the variable capacitance portions are arranged at predetermined positions on a seat portion and a backrest portion of a seat, and the variable capacitance portion is arranged at a predetermined position. The seating sensor according to claim 5, wherein the weight and the posture can be grasped. 7. The seating sensor according to claim 5, wherein the electrode is formed by printing on a resin film.