Capacitance type sensor and method for manufacturing same

• US 20030222660A1
• Filed: 05/28/2003
• Published: 12/04/2003
• Est. Priority Date: 05/29/2002
• Status: Active Grant

• Current Assignee: Nitta Corporation
• Original Assignee: Nitta Corporation
• Inventors: Morimoto, Hideo
• Granted Patent: US 6,958,614 B2
• Time in Patent Office: Days
• US Class Current: 324/661
• CPC Class Codes: G01L 1/142 using capacitors
• CPC Class Codes: G01L 1/144 with associated circuitry G01L1/146 and G01L1/148 take precedence
• CPC Class Codes: G01L 5/165 using variations in capacitance
• CPC Class Codes: G01L 5/223 to joystick controls
• CPC Class Codes: G01L 9/0072 using variations in capacitance
• CPC Class Codes: G06F 1/3215 Monitoring of peripheral devices
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: H01H 2025/048 having a separate central push, slide or tumbler button which is not integral with the operating part that surrounds it
• CPC Class Codes: H01H 2239/006 Containing a capacitive switch or usable as such
• CPC Class Codes: H01H 2300/022 Application wake up; switches or contacts specially provided for the wake up or standby shift of a circuit
• CPC Class Codes: H01H 25/041 having a generally flat operating member depressible at different locations to operate different controls
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 29/49005 Acoustic transducer
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49103 Strain gauge making

Abstract

In a capacitance type sensor of the present invention, a capacitance element is constituted between a displacement electrode and a capacitance element electrode. A return-switch movable electrode is arranged above and spaced from the displacement electrode, to be placed in contact with the displaying electrode due to a displacement of a direction button. When the direction button is operated, the return-switch movable electrode is first displaced into contact with the displacement electrode. Then, the both make a displacement while keeping a contact state. When the displacement electrode is displaced to change the spacing to the capacitance element electrode, changed is the capacitance value of the capacitance element. Based on this change, a force is recognized. Herein, in the course of a transit from a state the displacement electrode and the return-switch electrode are not in contact to a state of their contact, the output signal varies necessarily beyond a threshold voltage.

Claims

1. A capacitance type sensor characterized by comprising:

a conductive member;

a capacitance element electrode constituting a capacitance element with the conductive member; and

one or a plurality of movable electrodes arranged opposite to the capacitance element electrode with respect to and at a distance from the conductive member, the one or a plurality of movable electrodes being capable of, by being applied a force thereto, being displaced to be brought into contact with the conductive member and then displacing the conductive member, and

by being capable of recognizing a force applied to the movable electrode on the basis of a detection, using a signal input to the capacitance element electrode, of a change in capacitance value of the capacitance element caused by a change in distance between the conductive member and the capacitance element electrode.

7. The capacitance type sensor according to claim 1, characterized in that the movable electrode and the conductive member are formed of a conductive film, the conductive member being formed with a hole.

8. The capacitance type sensor according to claim 7, characterized in that provided is a mechanism for deforming into concavo-convex the movable electrode and the conductive member in a region not opposed to the capacitance element electrode so as to apply a tensile force thereto

12. A method for manufacturing the capacitance type sensor according to claim 1, characterized by comprising:

an insert molding process for insert-molding, with an insulating material, a part of each lead wire of a leadframe and a range of the leadframe including the capacitance element electrode, the leadframe being formed by integrally forming with a frame the capacitance element electrode, the lead wire thereof, and a lead wire of the movable electrode in a predetermined pattern;

a cutting process for cutting the lead wire of the capacitance element electrode off the frame;

a conductive member arranging process for arranging, to a mold product obtained by the insert molding process, the conductive member at a distance from the capacitance element electrode; and

a movable electrode arranging process for arranging, to the mold product, the movable electrode to be in contact with the lead wire of the movable electrode and at a distance from the conductive member.

13. The method for manufacturing a capacitance type sensor according to claim 12, characterized in that, in the insert molding process, insert-molding is carried out to form, in the mold product, a step for supporting the conductive member and a step for supporting the movable electrode.

2. A capacitance type sensor characterized by comprising:

a substrate;

a detective member being opposite to the substrate;

a conductive member disposed between the substrate and the detective member, and displaceable in a same direction as the detective member as the detective member is displaced in a direction vertical to the substrate;

a capacitance element electrode formed on the substrate and constituting a capacitance element with the conductive member;

one or a plurality of fixed electrodes formed on the substrate; and

one or a plurality of movable electrodes disposed between the detective member and the conductive member at a distance from the conductive member, and electrically connected to the fixed electrode, the one or a plurality of movable electrodes being capable of being brought into contact with the conductive member and then displacing the conductive member as the detective member is displaced, and

by being capable of recognizing the displacement of the detective member on the basis of a detection, using a signal input to the capacitance element electrode, of a change in capacitance value of the capacitance element caused by a change in distance between the conductive member and the capacitance element electrode.

3. A capacitance type sensor characterized by comprising:

a substrate;

a detective member being opposite to the substrate;

a conductive member disposed between the substrate and the detective member, and displaceable in a same direction as the detective member as the detective member is displaced in a direction vertical to the substrate;

a capacitance element electrode formed on the substrate and constituting a capacitance element with the conductive member;

a reference electrode formed on the substrate and electrically connected to the conductive member and grounded;

a fixed electrode formed on the substrate and kept at a different potential from a ground potential; and

a movable electrode disposed between the detective member and the conductive member at a distance from the conductive member, and electrically connected to the fixed electrode, the movable electrode being capable of being brought into contact with the conductive member and then displacing the conductive member as the detective member is displaced, and

by being capable of recognizing the displacement of the detective member on the basis of a detection, using a signal input to the capacitance element electrode, of a change in capacitance value of the capacitance element caused by a change in distance between the conductive member and the capacitance element electrode.

4. A capacitance type sensor characterized by comprising:

a substrate;

a detective member being opposite to the substrate;

a conductive member disposed between the substrate and the detective member, and displaceable in a same direction as the detective member as the detective member is displaced in a direction vertical to the substrate;

a capacitance element electrode formed on the substrate and constituting a capacitance element with the conductive member;

a reference electrode formed on the substrate and electrically connected to the conductive member, and kept at a different potential from a ground potential;

a fixed electrode formed on the substrate and grounded; and

a movable electrode disposed between the detective member and the conductive member at a distance from the conductive member, and electrically connected to the fixed electrode, the movable electrode being capable of being brought into contact with the conductive member and then displacing the conductive member as the detective member is displaced, and

by being capable of recognizing the displacement of the detective member on the basis of a detection, using a signal input to the capacitance element electrode, of a change in capacitance value of the capacitance element caused by a change in distance between the conductive member and the capacitance element electrode.

5. A capacitance type sensor characterized by comprising:

a substrate;

a detective member being opposite to the substrate;

a conductive member disposed between the substrate and the detective member, and displaceable in a same direction as the detective member as the detective member is displaced in a direction vertical to the substrate, the conductive member being maintained in an insulated state;

a capacitance element electrode formed on the substrate and constituting a capacitance element with the conductive member;

a fixed electrode formed on the substrate and grounded; and

a movable electrode disposed between the detective member and the conductive member at a distance from the conductive member, and electrically connected to the fixed electrode, the movable electrode being capable of being brought into contact with the conductive member and then displacing the conductive member as the detective member is displaced, and

by being capable of recognizing the displacement of the detective member on the basis of a detection, using a signal input to the capacitance element electrode, of a change in capacitance value of the capacitance element caused by a change in distance between the conductive member and the capacitance element electrode.

6. A capacitance type sensor characterized by comprising:

a substrate;

a detective member being opposite to the substrate;

a conductive member disposed between the substrate and the detective member, and displaceable in a same direction as the detective member as the detective member is displaced in a direction vertical to the substrate, the conductive member being maintained in an insulated state;

a capacitance element electrode formed on the substrate and constituting a capacitance element with the conductive member;

a first fixed electrode formed on the substrate;

a second fixed electrode formed on the substrate;

a first movable electrode disposed between the detective member and the conductive member at a distance from the conductive member, and electrically connected to the first fixed electrode; and

a second movable electrode disposed between the detective member and the conductive member at a distance from the conductive member, and electrically connected to the second fixed electrode,

the first fixed electrode being grounded and the second fixed electrode being kept at a different potential from a ground potential, the first and second movable electrodes being capable of being brought into contact with the conductive member and then displacing the conductive member as the detective member is displaced, and

by being capable of recognizing the displacement of the detective member on the basis of a detection, using a signal input to the capacitance element electrode, of a change in capacitance value of the capacitance element caused by a change in distance between the conductive member and the capacitance element electrode.

9. A capacitance type sensor characterized by comprising:

a detective member;

a substrate being opposite to the detective member;

a conductive member disposed between the detective member and the substrate, and displaceable in a same direction as the detective member as the detective member is displaced in a direction vertical to the substrate;

a capacitance element electrode formed on the substrate and constituting a capacitance element with the conductive member;

one or a plurality of movable electrodes disposed between the detective member and the conductive member at a distance from the conductive member, the one or a plurality of movable electrodes being capable of being brought into contact with the conductive member and then displacing the conductive member as the detective member is displaced,

a switch substrate;

a first switch electrode formed on the switch substrate; and

a second switch electrode kept at a ground or constant potential and disposed at a distance from the first switch electrode, the second switch electrode being capable of being brought into contact with the first switch electrode as the detective member is displaced, and

by being capable of recognizing the displacement of the detective member on the basis of a detection, using a signal input to the capacitance element electrode, of a change in capacitance value of the capacitance element caused by a change in distance between the conductive member and the capacitance element electrode, and recognizing a judgment as to whether or not the first and the second switch electrodes are in contact with each other by using a signal input to the first switch electrode.

10. A method for manufacturing a capacitance type sensor comprising a conductive member and a capacitance element electrode constituting a capacitance element with the conductive member, and capable of recognizing a force applied to the conductive member on the basis of a detection, using a signal input to the capacitance element electrode, of a change in capacitance value of the capacitance element caused by a change in distance between the conductive member and the capacitance element electrode, the method for manufacturing a capacitance type sensor being characterized by comprising:

an insert molding process for insert-molding, with an insulating material, a part of a lead wire of a leadframe and a range of the leadframe including the capacitance element electrode, the leadframe being formed by integrally forming with a frame the capacitance element electrode and the lead wire thereof in a predetermined pattern;

a cutting process for cutting the lead wire of the capacitance element electrode off the frame; and

a conductive member arranging process for arranging, to a mold product obtained by the insert molding process, the conductive member at a distance from the capacitance element electrode.

11. The method for manufacturing a capacitance type sensor according to claim 10, characterized in that, in the insert molding process, insert-molding is carried out to form, in the mold product, a step for supporting the conductive member.