JP2000294098A - Touch sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost touch sensor of high reliability capable of preventing destruction of component parts caused by static electricity, etc., capable of forming HIC while the construction remains small, and requiring no element for noise protection. SOLUTION: An oscillator circuit, chips 10, etc., are mounted on a base board 7 equipped therefor with circuit patterns, between which a pattern 8a connected with an electrode 6 and a pattern 8b connected with GND constitute a gap part G for noise protection. To this gap part G, a protecting member 9 is affixed to prevent a sealing material from intruding, and at least the member 9 and its surrounding area are sealed with the sealing material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a touch sensor used for detecting a human body, and more particularly, to a method of firing a ball such as a pachinko machine, unless a player touches an electrode provided on a firing handle. And a touch sensor suitable for preventing a player from using a plurality of pachinko machines.

[0002]

2. Description of the Related Art A touch sensor has a capacitance between a human body and ground.
The oscillation of the oscillation circuit is determined by whether or not the human body has touched the electrodes.
Detects contact with the human body by changing conditions
There is. FIG. 6 shows a circuit configuration of a conventional touch sensor of this kind.
Shown in In FIG. _ccIs constant in constant voltage circuit 1
Voltage, the oscillation circuit 2, the detection and smoothing circuit 3, the comparison circuit 4
Is supplied with power. The oscillation circuit 2 and the oscillation circuit 2
DC cut capacitor C_Four(Electrolytic protection) through the electrode
6 are connected. The electrode 6 has a noise protection
One end of the micro gap G (or varistor, etc.)
The other end of this micro gap G is connected to GND
Have been.

The output side of the oscillation circuit 2 has a detection and smoothing circuit 3
Are connected, and the oscillation output is detected and smoothed. The detection and smoothing circuit 3 is connected to a comparison circuit 4, and the detected and smoothed output signal is compared with a comparison voltage (constant value) by the comparison circuit 4, and an output corresponding thereto is input to the output circuit 5.
The output circuit 5 outputs an output signal indicating whether or not the human body has touched the electrode 6 according to the input of the comparison circuit 4.

When a human body having a ground-to-ground capacitance C ₀ comes into contact with the electrode 6, the oscillation condition of the oscillation circuit 2 changes and the oscillation output changes. This oscillation output is detected and smoothed by the detection and smoothing circuit 3 and input to the comparison circuit 4. In the comparison circuit 4, when the input level becomes lower than the comparison voltage, the output changes from the L level to the H level, and is input to the output circuit 5. The output circuit 5 outputs a human body contact detection signal.

If there is noise such as static electricity from the electrode 6, the circuit is protected by the micro gap G (or varistor or the like) for noise protection. As another conventional technology, the micro gap G for noise protection is
Some are formed by a circuit pattern on a substrate on which circuit components are mounted.

[0006]

In a touch sensor, a human body comes into contact with an electrode portion directly exposed on the surface. However,
The human body is constantly charged with static electricity by wearing synthetic or woolen clothes, walking on a carpet, or the like. Especially in winter,
This static electricity reaches tens of thousands of volts, and a high-voltage electrostatic discharge to the electrodes is constantly repeated.

As described above, the conventional touch sensor has the following problems. Parts are destroyed by static electricity or the like. Micro gaps and varistors that can withstand tens of thousands of volts of static electricity are large.
Micro gaps and varistors are connected externally,
The entire touch sensor cannot be downsized (HIC, etc.).

When a semiconductor noise protection element such as a varistor or a Zener diode is used, the detection capacitance C _d (10
The capacitance (several hundreds to several thousand pF of varistor, several tens to several hundreds of pF of the varistor) much larger than the noise protection element (set to about 0 pF) is connected as a part of the detection capacitance. The relationship between the oscillation gain of the oscillation circuit and the capacitance of the electrode is shown in FIG.
Approximate straight line having a gentle slope as shown in FIG. In this case, the detection output is turned ON / OFF with a small change in the detection capacity.
Will be done. Therefore, the operation becomes unstable due to environmental changes such as variations in capacitance of the noise protection element and temperature changes.

In the case where a noise protection gap is formed in a circuit pattern on a circuit board, the gap is several tens to ten.
There is only a few hundred μm, dust and dirt accumulate in the gap,
High impedance circuits can cause malfunctions. In the case of HIC, it is common to seal the substrate and the circuit portion with a sealing material such as an epoxy resin or a urethane resin in order to prevent dust, dust, moisture, etc. The gap portion for noise protection is also sealed, so that the noise is not discharged in the gap portion, so that it cannot be sealed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a touch sensor which achieves the following items a to d. a) Prevent the destruction of components due to static electricity or the like. b) It is small and can be made into HIC. c) High reliability.

D) An inexpensive device that does not require a noise protection element is provided.

[0012]

According to a first aspect of the present invention, there is provided a touch sensor, comprising: an oscillation circuit; and electrodes provided on the oscillation circuit. In a touch sensor that detects contact with a human body by changing the oscillation condition of the oscillation circuit due to contact, a gap portion for noise protection is formed on the substrate on which circuit components are mounted by a circuit pattern between the electrode and a power supply line. Is formed at least at one or more locations, and a protective member for preventing intrusion of a sealing material is provided in the gap portion, and at least the protective member and the periphery of the protective member are sealed with a sealing material.

In this touch sensor, when a hand or the like comes into contact with the electrodes and the static electricity is discharged, the static electricity is discharged to the power supply line through the noise protection gap. Therefore, a noise protection element is not required, and the touch sensor can be reduced in size and cost. Further, since there is no noise protection element, it is possible to prevent a malfunction due to an environmental change such as a variation in capacitance or a temperature change as in the case of using the noise protection element.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to embodiments. FIG. 1 is a block diagram showing a circuit configuration of a touch sensor according to an embodiment of the present invention. In FIG. 1, a power supply _Vcc has a constant voltage in a constant voltage circuit 1, and power is supplied to an oscillation circuit 2, a detection and smoothing circuit 3, and a comparison circuit 4. The electrode 6 is connected to the oscillation circuit 2 via a DC cut capacitor C ₄ (for preventing corrosion).

The output side of the oscillation circuit 2 has a detection and smoothing circuit 3
Are connected, and the oscillation output is detected and smoothed. The detection and smoothing circuit 3 is connected to a comparison circuit 4, and the detected and smoothed output signal is compared with a comparison voltage (constant value) by the comparison circuit 4, and an output corresponding thereto is input to the output circuit 5.
The output circuit 5 outputs an output signal indicating whether or not the human body has touched the electrode 6 according to the input of the comparison circuit 4.

The oscillating circuit 2 is a Colpitts oscillating circuit including capacitors C ₁ and C ₂ , a coil L and a transistor Tr. Resistor R ₁ is a feedback resistor for oscillation gain adjustment resistors R _2, R ₃ is a bias resistor of transistor Tr. Capacitors C ₃ and C ₅ are bypass capacitors. When radio noise from a mobile phone or the like is received from the electrode 6, the radio noise is
_4, through the C _5, C _3, no effect on the oscillation circuit 2 for escapes to the power supply line, preventing malfunctions due to radio noise.

As shown in FIG. 2, between the electrode 6 and GND, of the circuit pattern on the printed circuit board 7 on which the circuit shown in FIG. Pattern 8b connected to GND
Thus, a noise protection gap G is provided. The gap g of the gap G is 0.1 to 0.2 mm.
is necessary. In FIG. 2, however, only one noise protection gap G is provided. However, in consideration of an etching defect or the like at the time of manufacturing the printed circuit board 7, a plurality of (three in this case) as shown in FIG. It is desirable to form the gap G.

A protective member 9 with an adhesive for preventing intrusion of a sealing material (epoxy resin, urethane resin or the like) is attached to the noise protection gap portion G.
Covers the gap G. In addition, the protection member 9
A seal or the like with an adhesive is optimal, but any material can be used as long as a space capable of discharging can be secured without closing the gap g with the sealing material.

A chip component 10 and the like are mounted on a printed circuit board 7, a protection member 9 is attached to the noise protection gap G, and the printed circuit board 7 is placed in a case (not shown). Filled with sealing material. In FIG. 4 showing an enlarged cross-sectional view of a main part in a sealed state with a sealing material,
The adhesive of the protection member 9 prevents the sealing material 11 from entering the noise protection gap G and secures a dischargeable gap g.

[0020] In such a touch sensor configured to, when a human body having the earth capacitance C ₀ is contacted to the electrode 6, and decreases the selectivity Q oscillation circuit 2, the gain of the oscillation decreases. The oscillation is detected and smoothed by the detection and smoothing circuit 3 and input to the comparison circuit 4 as a signal having a lowered voltage level. In the comparison circuit 4, when the input level becomes equal to or lower than the comparison voltage, the output becomes L
The level changes from the level to the H level and is input to the output circuit 5.
The output circuit 5 outputs the signal as a contact detection signal of a human body.

The relationship between the oscillation gain of the oscillation circuit 2 and the capacitance of the electrode 6 is an approximate straight line having a large slope near the detection capacitance as shown in FIG. in this case,
The detection output is not turned on / off by a small change in the detection capacity. Therefore, even if there is an environmental change such as a temperature change, the detection operation is stable. When static electricity is discharged to the electrode 6 when the human body comes into contact with the electrode 6, discharge occurs in the gap g, and the noise protection gap portion G
A current flows through D and the circuit is protected.

In the present invention, the oscillation circuit 2 is not limited to the Colpitts type, but may be a Hartley type oscillation circuit. In addition, this touch sensor is not only for pachinko machines, but also for ON / OFF switches of electronic devices,
The present invention can be used for any device that detects contact with a human body, such as a door knob switch and an elevator switch.

[0023]

The touch sensor of the present invention has the following effects because it is configured as described above. (1) Since noise such as static electricity is reliably absorbed by the noise protection gap, destruction of components can be prevented. (2) Since a noise protection element is not required, the size is small and the HI
C can be used and the cost can be reduced. (3) The capacitance does not affect the oscillation circuit as in the case of using the noise protection element, the temperature characteristic is good, the detection operation is stable, and the reliability of the circuit is improved. (4) Since the sealing member does not enter the noise protection gap by the protection member, dust, dust, moisture, and the like can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a circuit configuration of a touch sensor according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a noise protection gap portion of the touch sensor according to the embodiment of the present invention.

FIG. 3 is a perspective view showing a modified example of the noise protection gap of FIG. 2;

FIG. 4 is an enlarged sectional view of a main part of a noise protection gap portion of the touch sensor according to the embodiment of the present invention.

FIG. 5 is a graph showing the relationship between the capacitance C _{0 of the} electrode and the oscillation gain.

FIG. 6 is a block diagram showing a circuit configuration of a conventional touch sensor.

[Explanation of symbols]

 2 Oscillation circuit 6 Electrode 7 Printed circuit board 8a, 8b Circuit pattern 9 Protective member 11 Sealing material G Noise protection gap g Gap

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5G046 AA01 AA11 AB02 AC23 AD25 AE22 5J050 AA13 AA34 AA37 AA47 AA49 AA50 BB23 DD04 EE34 EE35

Claims (2)

[Claims] 1. A touch sensor comprising: an oscillation circuit; and electrodes provided on the oscillation circuit. The touch sensor detects a contact of a human body by changing an oscillation condition of the oscillation circuit due to a contact of the human body with the electrodes. Forming at least one gap portion for noise protection in a circuit pattern between the electrode and the power supply line on a substrate on which circuit components are mounted, and providing a protection member for preventing intrusion of a sealing material into the gap portion; A touch sensor, wherein at least the protection member and the periphery of the protection member are sealed with a sealing material. 2. The touch sensor according to claim 1, wherein the protection member is a seal.