Proximity sensor and object detecting device
First Claim
1. A proximity sensor comprising:
- a detecting electrode arranged in an object detecting area and made of a metal plate formed like a plate;
a charge system with a direct current power source;
a discharge system with current detecting means; and
a switch for alternately switching said charge system and said discharge system to said detecting electrode by a specified switching frequency, wherein an electrostatic capacity between a detected object and said detecting electrode is detected as current (Is) flowing in said discharge system.
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Accused Products
Abstract
In a proximity sensor, in order that it is not affected by a cable length and an environment of a setting place or the like, and that it is extremely stable in operation, and that it can be used nearing in a maintenance-free state, there are included a detecting electrode arranged in an object detecting area and made of a metal plate formed like a plate; a charge system with a direct current power source; a discharge system with a current detecting unit; and a switch for alternately switching the charge system and the discharge system to the detecting electrode by a specified switching frequency, and an electrostatic capacity between a detected object and the detecting electrode is detected as current flowing in the discharge system.
172 Citations
20 Claims
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1. A proximity sensor comprising:
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a detecting electrode arranged in an object detecting area and made of a metal plate formed like a plate;
a charge system with a direct current power source;
a discharge system with current detecting means; and
a switch for alternately switching said charge system and said discharge system to said detecting electrode by a specified switching frequency, wherein an electrostatic capacity between a detected object and said detecting electrode is detected as current (Is) flowing in said discharge system. - View Dependent Claims (2, 3, 4, 20)
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5. A proximity sensor comprising:
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a detecting electrode arranged in an object detecting area and made of a metal plate formed like a plate;
an earthed ground electrode arranged facing to the same detecting electrode;
a charge system with a direct current power source;
a discharge system with current detecting means; and
a double shield wire with an inside skin shield and an outside skin shield around a central conductor, wherein said detecting electrode is connected to one end of said central conductor, and to the other end side thereof, a first switch for alternately switching said charge system and said discharge system to the same central conductor by a specified switching frequency, and at the same time, to said inside skin shield, a second switch for alternately switching the same inside skin shield to said charge system and the earth in synchronization with said first switch is provided, and said ground electrode is connected to said outside skin shield. - View Dependent Claims (6)
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7. A proximity sensor comprising:
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a first and a second detecting electrodes both of which are made of a metal plate with the same size formed like a plate, and are set in parallel approximately on the same plane in an object detecting area;
a charge system with a direct current power source;
a discharge system with current detecting means; and
switch means for alternately switching both said first and second detecting electrodes to said charge system and said discharge system by a specified switching frequency. - View Dependent Claims (8, 9)
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10. A proximity sensor comprising:
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a first and a second detecting electrodes both of which are made of a metal plate with the same size formed like a plate, and are set in parallel approximately on the same plane in an object detecting area;
a charge system with a direct current power source;
a discharge system with current detecting means; and
main switch means for alternately switching both said first and second detecting electrodes to said charge system and said discharge system by a specified switching frequency, wherein said discharge system is provided in parallel between said main switch means and said current detecting means, and comprises;
a first discharge circuit connected to said first detecting electrode side; and
a second discharge circuit connected to said second detecting electrode side, and to said one discharge circuit, a signal reversing circuit made of a capacitor and a sub switch for alternately separating both ends of the same capacitor from the same discharge circuit to connect the ends to the earth terminal is provided, and each time said main switch means is switched, the polarity of said capacitor is reversed by said sub switch. - View Dependent Claims (15, 16, 17, 18)
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11. A proximity sensor comprising:
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a first and a second detecting electrodes both of which are made of a metal plate with the same size formed like a plate, and are set in parallel approximately on the same plane in an object detecting area;
a drive electrode arranged facing common to each of the detecting electrodes;
a charge system with a direct current power source;
a discharge system with a condenser and current detecting means;
a first switch for selectively connecting at least one pole of said direct current power source to said drive electrode by a specified switching frequency;
a second switch for alternately connecting each of said detecting electrodes together to said the same pole of said direct current power source and said condenser in synchronization with the same first switch; and
a third switch for alternately connecting said condenser to said each detecting electrode and said current detecting means in synchronization with said each switch. - View Dependent Claims (12)
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13. A proximity sensor comprising:
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a first and a second detecting electrodes both of which are made of a metal plate with the same size formed like a plate, and are set in parallel approximately on the same plane in an object detecting area;
a drive electrode arranged facing common to each of the detecting electrodes;
a charge system with a direct current power source;
a discharge system with a first and a second condensers and current detecting means;
a first switch for selectively connecting at least one pole of said direct current power source to said drive electrode by a specified switching frequency;
a second switch for synchronous detection for alternately replacing and connecting each of said detecting electrodes to both poles of said first condenser in synchronization with the same first switch; and
a third switch for alternately connecting said second condenser to said first condenser and said current detecting means in synchronization with said each switch. - View Dependent Claims (14)
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19. An object detecting device comprising:
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a sensor surface including a plurality of detecting electrodes set in parallel along the line direction and the row direction on the same plane;
a drive electrode arranged approximately through the total surface on the rear side of said sensor surface through a dielectric layer;
a charge system with a direct current power source;
a discharge system with current detecting means;
a plurality of charge wirings wired along either the line direction of said sensor surface or said row direction on the anti-sensor surface side of said drive electrode and a plurality of discharge wirings wired along the other;
a detecting electrode switching switch for selectively connecting said each detecting electrode separately to either said charge wiring or said discharge wiring;
a first scanner switch for sequentially connecting said each charge wiring to the direct current power source of said charge system;
a second scanner switch for sequentially connecting said each discharge wiring to the current detecting means of said discharge system;
a drive electrode switching switch for selectively connecting said drive electrode to either the direct current power source of said charge system or the earth; and
control means for controlling said each switch, wherein each time said charge wiring is connected to said direct current power source one by one, by switching said first scanner switch, said control means performs;
a first step of switching said drive electrode switching switch to said direct current power source side, and of simultaneously switching said detecting electrode switching switch selected by said first scanner switch and existing along said charge wiring, to the same charge wiring side;
a second step of switching said drive electrode switching switch to said earth side after said first step, and of simultaneously switching said detecting electrode switching switch switched to said charge wiring side at said first step, to said discharge wiring side; and
a third step of sequentially switching said second scanner switch to go around after said second step.
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Specification