JP4306715B2 - Pressure sensitive switch - Google Patents

Description

  The present invention relates to a mechanical switch in which a plurality of electrical conductors are mechanically connected to and separated from each other by a pressing force. In particular, although not intended to be limited to this, a seat (seat) is attached to a seat (seat). The present invention relates to a sheet-like (flexible thin plate-like) pressure-sensitive switch for binaryly detecting whether or not an electric conductor is in contact with or separated from it.

Japanese Patent Publication No. 8-2535120 Japanese Patent Publication No. 2-49029.

  For example, as a sensor that senses that a person is seated in a vehicle seat, a conventionally known sensor is provided with a magnetic generator on a seat and is moved by a magnetic generator that moves up and down as the seat moves up and down. There is a type in which a magnetic detection device that detects a change in a moving magnetic field is provided on a vehicle floor, and the magnetic detection device detects seat lowering based on a change in the seat based on the change in the magnetic field. Moreover, in the method disclosed in Patent Document 1, the seat pressure that changes due to the seating of a person is detected based on the change in the resistance value of the piezoelectric film.

  In addition, as a pressure-sensitive sensor used for the purpose other than sensing the seating state of the above-mentioned seat, as disclosed in Patent Document 2, pressure sensitivity of a keyboard of an electric device for generating a musical sound is disclosed. As a switch, there is a pressure-sensitive sensor that detects an applied pressure based on a change in resistance value between two conductor plates facing each other with a semiconductor interposed therebetween.

  However, in the method of detecting the change of the magnetic field due to the vertical movement of the magnetic means by the magnetic detection means, the seat detection is performed from the vertical movement of the seat with respect to the vehicle floor. It is necessary to ensure that the seat moves up and down with respect to the vehicle floor when seated on the vehicle. As a result, the device itself becomes complicated in order to increase the detection accuracy, thereby increasing the cost. Invite. Also in the method disclosed in Patent Document 1, the piezoelectric film is expensive, and it is necessary to provide a feedback loop for constantly oscillating the piezoelectric film and a filter for detecting an oscillation signal of the piezoelectric film. Since the apparatus becomes complicated, the cost is increased.

  Furthermore, the pressure-sensitive sensor disclosed in Patent Document 2 is provided to sense the pressure of a keyboard that a player taps with a finger, and is used as a pressure-sensitive switch that senses pressure due to a person's weight. There is a problem with impact resistance. In addition, the switch itself is expensive, such as using silver or copper for the conductor plate.

  In addition, when detecting whether there is a seated person in the seat, the load is surface-distributed on the seat base (the seating base for receiving the person's weight) and the load distribution is uneven, so a mechanical switch is arranged at one point. Therefore, there is a high possibility of causing a detection error. In addition, the presence of a single mechanical switch gives the seated person a sense of incongruity (a solid feeling that the solid matter is inside the sheet).

  The first object of the present invention is to provide a pressure-sensitive switch that is inexpensive and excellent in impact resistance, and the second object is to provide a pressure-sensitive switch with few detection errors. The third object of the present invention is to provide a pressure-sensitive switch that has high reliability in seating detection, does not give a sense of discomfort to the seated person, and has high durability.

(1) The pressure-sensitive switch of the present invention has a conductive layer (1d to 1i) on the back surface, bends at a curvature of a predetermined value or more at a plurality of locations along the x, y plane, and is distributed in the x, y plane. A first film (1) having a body band shape; a first film (1) having a plurality of holes (2d, 2e) penetrating in the thickness direction z and having a surface bonded to the back surface of the first film (1) An insulating spacer (2) having substantially the same shape as that of the first film (1); and a conductive layer (3d-3i) on the surface, the surface being bonded to the back surface of the spacer (2), the second film of the insulator having the same shape (3); have a, Ru der those disposed on the sheet.

  In addition, in order to make an understanding easy, the symbol of the corresponding | compatible element of the Example shown in drawing and mentioned later is added to the parenthesis for reference.

  According to this pressure sensitive switch, when no special pressing force is applied, the opposing conductive layers (1d, 3d) are separated by the elasticity of each film in the holes (2d, 2e) of the spacer (2). Yes. That is, the pressure sensitive switch is open (switch off). However, when a strong pressing force that bends the first film (1) and the second film (3) is applied, the first film (1) and the second film (3) are inserted into the large openings (2d, 2e). The conductive layers (1d, 3d) come into contact with each other. That is, the switch is closed (switch on).

Since a plurality of holes (2d, 2e) are distributed throughout the strip, when the seat occupant is present, the conductive layer of the first film (1) and the second film in any of the hole (3) Since (1d, 3d) contacts, seating detection is reliable. Since the switch substrate is a film, the impact resistance is high. In addition, since the pressure-sensitive switch is a flexible belt-like sheet, it is further belt-like and bends along the x and y planes. Don't give. If a corner bent along the x and y planes has a corner like a triangular apex, stress concentrates on the corner and is easily broken, but the pressure sensitive switch of the present invention is Since it has a curvature equal to or greater than a predetermined value, it is difficult to cause such breakage and has high durability.

( 2 ) The first film (1), the second film (3), and the spacer (2) are in the shape of a belt having a branch, and the branch is made between the holes. The pressure sensitive switch according to (1), wherein the hole is not formed.

  Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

  FIG. 1 shows the top surface of a pressure sensitive switch PSS of one embodiment of the present invention. This pressure-sensitive switch PSS is formed by laminating a cover film 1 (first film), an insulating spacer 2 and a support film 3 (second film) in a sandwich shape and integrally joining them. The upper surfaces of these three parties 1 to 3 are shown in FIGS.

  The pressure-sensitive switch PSS shown in FIG. 1 is made of polyethylene naphthalate, which is made of polyethylene naphthalate. The pressure sensitive switch PSS is made of polyethylene naphthalate, which is made of polyethylene naphthalate, and faces the surface of the support film 3 in parallel. The cover film 1 (thickness 100 μm) shown in FIG. 2 and the spacer 2 (125 μm) shown in FIG. 3 of an insulator (polyethylene terephthalate) sandwiched between the support film 3 and the cover film 1 are configured.

  As shown in FIG. 6, the pressure-sensitive switch PPS shown in FIG. 1 is a seating detection switch built in the vicinity of the surface layer of the seat portion of a seat (seat) on the vehicle. The films 1 and 3 and the insulating spacer 2 are different in thickness but have the same shape.

  The spacer 2 (FIG. 3) is a shape in which the strip-shaped lead portion 2a, the backbone 2b, and the branch 2c are roughly distributed in a fork-like shape, and z is the thickness direction. Five holes 2d (diameter 10 mm) arranged in a straight line are opened on the center line of the width of the backbone 2b, and one similar hole 2e is opened at each tip of each of the five branches 2c. These holes 2e are also arranged in a straight line. The arrangement pitch is determined so that these two rows in total 10 holes 2d and 2e are distributed in a region where the weight of the seated person on the vehicle seat is added.

  Since the spacer 2 has a thickness of 125 μm and a hole diameter of 10 mm, the holes 2d and 2e are large openings with respect to the spacer thickness, and the ratio (magnification) of the hole diameter to the spacer thickness is the cover film. When a force in the direction of pushing 1 to the support film 3 or vice versa is applied, the film bends and the conductive layers of the films 1 and 3 come into contact with each other with a force greater than a set value. Are set apart so that the conductive layers are separated.

  The backbone 2b has a constriction at the connecting portion so that each region around the holes 2d and 2e is easily bent with respect to the connecting portion between the regions. Due to this constriction, the backbone 2b bends along the x and y planes. If the bend is sharp like the apex of a triangle, the smoothness of bending will be lost there, stress will concentrate there, and breakage will easily occur. To improve this, a large curvature (R; roundness) should be used as much as possible. Attached. The branch 2c is also bent with respect to the backbone 2b, and the bent portion is constricted and curved for the same reason.

  The shape of the support film 3 (FIG. 4) bonded to the back surface of the spacer 2 is the same as that of the spacer 2, and has a strip-shaped lead portion 3a, a backbone 3b, and a branch 3c. Note that the lead portion 3a is slightly longer than the spacer 2a for lead wire connection. On the surface of the support film 3, there is a conductive layer (an electrode formed by a printing technique), and this conductive layer is rounded at the position corresponding to the holes 2 d and 2 e of the spacer 2 to the same extent as the diameter of the holes 2 d and 2 e. The electrode portion 3d (position corresponding to the hole 2d), 3e (position corresponding to the hole 2e), the connecting portions 3f and 3g, the lead portion 3h, and the lead tab 3i are integrally formed.

  The shape of the cover film 1 (FIG. 2) bonded to the surface of the spacer 2 is the same as the shape of the spacer 2, and has a strip-shaped lead portion 1a, a backbone 1b, and a branch 1c. Note that the lead portion 1a is slightly longer than the spacer 2a due to the lead wire connection. On the back surface (lower surface) of the cover film 1, there is a conductive layer (an electrode formed by a printing technique), and this conductive layer has a diameter corresponding to the holes 2 d and 2 e of the spacer 2. 1d (position corresponding to the hole 2d), 1e (position corresponding to the hole 2e), the connecting portions 1f and 1g, the lead portion 1h, and the lead tab 1i. The electrode portions 1d, 1e of the conductive layer formed on the cover film 1 are positions facing the electrode portions 3d, 3e of the base film 3 at the holes 2d, 2e, but the connecting portions 1f, 1g, The positions of the lead portion 1h and the lead tab 1i are shifted so as not to oppose the base film 3 as much as possible.

  The support film 3, the insulating spacer 2 and the cover film 1 are superposed in this order, and the three members are joined together (FIG. 1). Then, the cover film 1 and the support film 3 are relatively insulated by the insulating spacer 2. Thus, the pressure sensitive switch PSS shown in FIG. 1 is completed.

  The lead tab 3i is exposed on the front surface side of the completed pressure-sensitive switch PSS (FIG. 1), and the lead tab 1i is exposed on the back surface side. Connector pins are connected here.

  FIG. 5 shows an enlarged cross section taken along line 5A-5A in FIG. For example, when this pressure sensitive switch PSS is mounted on a seat (seat) on the vehicle as shown in FIG. 6, when a person is not seated, a pressing force is not substantially applied to the pressure sensitive switch PSS. In the hole 2d, the conductive layers 1d and 3d are not in contact with each other, and the lead tabs 1i and 3i are disconnected (switched off). When a person sits in the range where the pressure sensitive switch PSS is disposed, the cover film 1 is bent by the weight (pushing force) of the seated person and falls into the hole 2d of the insulating spacer 2, and the conductive layer on the lower surface of the cover film 1 1 d contacts the conductive layer 3 d on the upper surface of the support film 3. As a result, the lead tabs 1i and 3i are in contact (switched on).

  According to the above embodiment, since the pressure sensitive switch PSS has a belt-like winding shape, when it is attached to the sheet, it bends in the same way as the sheet cushion is bent by the weight of the seated person. Does not give a sense of incongruity to the seated person. Since the films 1 and 3 and the spacer 2 have high flexibility, they have high impact resistance. Since multiple holes, which are pressure sensitive units, are distributed over a wide area on the x and y planes, when there is seating, the conductive layers of the upper and lower films come into contact with each other in the hole where a load of a predetermined pressure or more is applied. High reliability. When bending, stress tends to concentrate on the corner and branching angle, but since a large alarm (bending at a certain curvature) is formed there, the stress is distributed along this alarm arc. It is difficult to crack and has high durability.

  The polyethylene naphthalate used as the material for the cover film 1 and the support film 3 has high mechanical strength and is suitable for receiving pressure due to the weight of a person under the seat. Further, the glass transition point Tg point at which the physical properties (specific heat, expansion rate, compression rate, etc.) change is as high as 113 degrees and the durability against high heat is good, so that it can withstand severe use conditions in the vehicle. The conductive layers 1d and 3d may be any conductor and can be formed relatively easily and inexpensively, so that the pressure sensitive switch PSS can be provided at low cost.

It is a top view of one example of the present invention. It is a top view of the cover film 1 of the pressure sensitive switch PSS shown in FIG. It is a top view of the spacer 2 of the pressure sensitive switch PSS shown in FIG. It is a top view of the support film 3 of the pressure sensitive switch PSS shown in FIG. It is the 5A-5A line expanded sectional view of FIG. FIG. 2 is a side view of a seat on the vehicle, and shows a position of the switch when the pressure sensitive switch PSS shown in FIG. 1 is mounted on a seat (seat) on the vehicle as a seating detection switch.

PSS: Pressure sensitive switch 1: Cover film 2: Insulating spacer 3: Support films 1a, 2a, 3a: Band-shaped lead portions 1b, 2b, 3b: Band-shaped backbones 1c, 2c, 3c: Band-shaped branches 1d, 3d : Electrode portions 1e and 3e of the conductive layer: Electrode portions 2d and 2e of the conductive layer: Holes 1f, 1g, 3f and 3g: Connection portions 1h and 3h of the conductive layer: Lead portions 1i and 3i of the conductive layer Dotab

Claims (2)

An insulating strip-shaped first film having a conductive layer on the back surface, bent at a curvature of a predetermined value or more at a plurality of locations along the x, y plane, and distributed in the x, y plane;
An insulating spacer having a plurality of holes penetrating in the thickness direction z and having a surface bonded to the back surface of the first film and having substantially the same shape as the first film; and
A second film of an insulator having a conductive layer on the surface, the surface being bonded to the back surface of the spacer, and substantially the same shape as the first film;
It has a pressure-sensitive switch that will be provided to the sheet.   The said 1st film, the said 2nd film, and the said spacer are strip | belt shape which has a branch, The said branch is made between the said holes, and the said hole is not formed in the part by which the said branch is made. Pressure-sensitive switch.

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