JP2016164541A - Proximity sensor and game machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a proximity sensor with which it is possible to suppress an incorrect operation due to the irradiation of an electromagnetic field.SOLUTION: The proximity sensor has: a detection circuit (10) which oscillates with one of a plurality of resonance frequencies and whose oscillation amplitude becomes smaller as the distance to a detection object is shortened; a first determination circuit (13, 23), connected to the detection circuit (10), for outputting a first voltage when the oscillation amplitude of the detection circuit (10) is larger than a first threshold, and meanwhile outputting a second voltage when the oscillation amplitude of the detection circuit (10) is smaller than the first threshold; and a second determination circuit (14, 24), connected to the detection circuit (10), for making the resonance frequency of the detection circuit (10) be a first resonance frequency when the oscillation amplitude of the detection circuit (10) is larger than the second threshold that is smaller than the first threshold, and meanwhile making the resonance frequency of the detection circuit (10) be a second resonance frequency when the oscillation amplitude of the detection circuit (10) is smaller than the second threshold.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a proximity sensor that detects the approach of an object to be detected such as a magnetic body, and a gaming machine having such a proximity sensor.

  Conventionally, in a gaming machine, a proximity sensor has been used to detect the approach or passage of an object to be detected such as a game ball having magnetism. Such a proximity sensor has, for example, an oscillation circuit and a resonance circuit. When the game ball is sufficiently far away, the oscillation circuit and the resonance circuit oscillate in a steady state. On the other hand, when the game ball approaches the proximity sensor, the oscillation conditions of the oscillation circuit and the resonance circuit change, and the oscillation circuit and the resonance circuit Stops oscillation. The proximity sensor outputs a signal having a different voltage when the oscillation circuit and the resonance circuit are oscillating and when the oscillation is stopped. Thereby, the approach of the game ball to the proximity sensor is detected.

  On the other hand, fraudulent acts that cause the proximity sensor to erroneously detect a game ball by repeating generation and stop of an electromagnetic field having a frequency substantially matching the resonance frequency of the resonance circuit of the proximity sensor in the vicinity of the proximity sensor are known. . Therefore, techniques for preventing such illegal acts have been proposed (see, for example, Patent Documents 1 and 2).

  For example, the low-frequency near electromagnetic field detection circuit disclosed in Patent Document 1 has a high-frequency oscillation circuit, and the high-frequency oscillation circuit stops oscillation when the low-frequency near electromagnetic field is not irradiated to the detection electrode. On the other hand, it oscillates when a low-frequency near electromagnetic field is irradiated to the detection electrode. As a result, the low-frequency near electromagnetic field detection circuit can detect the irradiation of the low-frequency near electromagnetic field, so that the control circuit can know that an abnormality has occurred by notifying the control circuit of the detection result, for example. .

  In addition, the game ball detection switch disclosed in Patent Document 2 includes a coil that detects the arrival of a low-frequency near electromagnetic field by inducing voltage, separately from the game ball detection coil. And the two coils are arrange | positioned so that the magnetic flux generation direction may correspond. Thereby, this game ball detection switch detects the game ball by making the output voltage when the arrival of the low-frequency near electromagnetic field different from the output voltage when the low-frequency near electromagnetic field does not arrive. Separately from this, it is possible to detect the arrival of an electromagnetic field in the vicinity of a low frequency.

JP 2010-256245 A JP 2012-152512 A

  In any of the techniques of Patent Documents 1 and 2, a circuit for detecting a low-frequency near electromagnetic field is provided separately from the game ball detection oscillation circuit. Therefore, the game ball detection oscillation circuit itself reacts to repeated irradiation and non-irradiation of the electromagnetic field.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a proximity sensor that can suppress malfunction caused by electromagnetic field irradiation.

  As one form of this invention, a proximity sensor is provided. This proximity sensor oscillates at any of a plurality of resonance frequencies, and is connected to a detection circuit and a detection circuit whose amplitude decreases as the distance from the object to be detected decreases. The first voltage is output when the amplitude of the detection circuit is larger than the first threshold value, and the second voltage different from the first voltage is output when the amplitude of oscillation of the detection circuit is smaller than the first threshold value. The resonance frequency of the detection circuit is selected from among the plurality of resonance frequencies when the amplitude of oscillation of the detection circuit is greater than a second threshold value that is smaller than the first threshold value. On the other hand, when the amplitude of oscillation of the detection circuit is smaller than the second threshold, the resonance frequency of the detection circuit is different from the first resonance frequency among the plurality of resonance frequencies. And a second determination circuit .

  In this proximity sensor, the detection circuit includes a first coil, a first capacitor connected in parallel with the first coil, and a second capacitor connected in parallel with the first coil and the first capacitor. And a switching element connected in parallel with the first coil and the first capacitor, connected in series with the second capacitor, and switching whether to energize the second capacitor. In this case, the detection circuit oscillates at the first resonance frequency when the switching element is turned off and the second capacitor is not energized, while the detection circuit is oscillated at the first resonance frequency when the switching element is turned on and energized the second capacitor. Oscillates at the second resonance frequency. When the amplitude of oscillation of the detection circuit is smaller than the second threshold value, the second determination circuit turns off the switching element and stops energizing the second capacitor, while the amplitude of oscillation of the detection circuit is When the threshold value is larger than 2, the second determination circuit preferably turns on the switching element to energize the second capacitor.

  Alternatively, in the proximity sensor, the detection circuit includes a first coil, a first capacitor connected in parallel with the first coil, and a second capacitor connected in parallel with the first coil and the first capacitor. And a switching element that is connected in parallel with the first coil and the first capacitor, is connected in series with the second coil, and switches whether to energize the second coil. preferable. In this case, the detection circuit oscillates at the first resonance frequency when the switching element is turned off and the second coil is not energized, while the detection circuit is oscillated at the first resonance frequency when the switching element is turned on and energized the second coil. Oscillates at the second resonance frequency. When the oscillation amplitude of the detection circuit is smaller than the second threshold, the second determination circuit turns off the switching element and stops energization of the second coil, while the oscillation amplitude of the detection circuit is If the threshold value is larger than 2, the second determination circuit preferably turns on the switching element to energize the second coil.

  According to another aspect of the present invention, a gaming machine main body, a winning device provided on a front surface of the gaming machine main body, and provided in any of a plurality of paths along which the gaming balls can flow down, and a winning device A proximity sensor for detecting that a game ball has entered, a ball payout device for paying out the game ball, and when a game ball entering the winning device is detected by the proximity sensor, a predetermined number of game balls are transferred to the ball payout device. A gaming machine having a control unit for paying out is provided. In this gaming machine, the proximity sensor is any one of the proximity sensors described above.

  The proximity sensor according to the present invention has an effect that it is possible to suppress malfunctions due to electromagnetic field irradiation.

It is a circuit diagram of a proximity sensor concerning one embodiment of the present invention. It is a timing chart which shows the time change of the voltage of each part of a proximity sensor when the electromagnetic field with the resonant frequency of a resonant circuit is not irradiated. It is a timing chart which shows the time change of the voltage of each part of a proximity sensor when the electromagnetic field with the resonance frequency of a resonance circuit is irradiated. It is a circuit diagram of a proximity sensor according to a modification. It is a timing chart which shows the time change of the voltage of each part of a proximity sensor when the electromagnetic field with the resonant frequency of a resonant circuit is not irradiated by the modification. It is a timing chart which shows the time change of the voltage of each part of a proximity sensor when an electromagnetic field with the resonant frequency of a resonant circuit is irradiated by a modification. It is a circuit diagram of the resonance circuit by another modification. It is an external appearance perspective view of the proximity sensor by said embodiment or a modification. It is a schematic perspective view of the gaming machine in which the proximity sensor according to the above embodiment or modification is mounted.

  Hereinafter, a proximity sensor according to an embodiment of the present invention will be described with reference to the drawings. This proximity sensor has a detection circuit having an LC resonance circuit in which the amplitude of oscillation decreases as an object to be detected such as a magnetic substance approaches. The LC resonant circuit has two capacitors and a coil connected in parallel with each other. The proximity sensor detects the change in the amplitude of the oscillation of the detection circuit, and the second determination circuit having a smaller threshold for the change in amplitude than the first determination circuit that switches the output voltage from the proximity sensor, the LC resonance circuit A switch that switches whether or not to energize one of the two capacitors is turned on / off to change the resonance frequency of the LC resonance circuit. Thereby, even if this proximity sensor is irradiated with an electromagnetic field having a frequency substantially equal to the resonance frequency of the LC resonance circuit, the resonance frequency is switched before the first determination circuit changes the output voltage. Thereby, this proximity sensor suppresses the malfunction by the electromagnetic field irradiation to a detection circuit.

  In the following embodiments, the proximity sensor is used in a gaming machine and detects a game ball. However, this proximity sensor may be used for applications other than gaming machines.

  FIG. 1 is a circuit diagram of a proximity sensor according to one embodiment of the present invention. As shown in FIG. 1, the proximity sensor 1 includes a detection circuit 10, a first determination circuit 13, and a second determination circuit 14.

  The detection circuit 10 detects the approach of the game ball by a change in the oscillation state. In the present embodiment, the detection circuit 10 performs steady oscillation when the game ball is sufficiently separated, and decreases the amplitude of the oscillation as the game ball approaches. For this purpose, the detection circuit 10 includes a resonance circuit 11 and an oscillation circuit 12.

  The resonance circuit 11 includes a coil L and two capacitors C1 and C2 connected in parallel to each other. Furthermore, the resonance circuit 11 includes an NPN transistor Tr1, which is an example of a switch, connected in parallel to the coil L and the capacitor C1, and connected in series to the capacitor C2. One end of each of the coil L and the capacitors C1 and C2 is connected to an output terminal on the high voltage side of the resonance circuit 11. On the other hand, the other ends of the coil L and the capacitor C1 are grounded. Similarly, the other end of the capacitor C2 is grounded to the collector of the transistor Tr1, and the emitter of the transistor Tr1 is grounded. Note that the connection positions of the transistor Tr1 and the capacitor C2 may be interchanged.

ここで、Lは、コイルLのインダクタンスであり、C1は、コンデンサC1の静電容量である。一方、トランジスタTr1がオンのとき、共振回路１１の共振周波数f2は次式で表される。

ここで、C2は、コンデンサC2の静電容量である。もし、C1=C2であれば、共振周波数f2は、共振周波数f1の略0.7倍となる。 The resonance circuit 11 operates as an LC resonance circuit composed of the coil L and the capacitor C1 when the transistor Tr1 is off. On the other hand, the resonance circuit 11 operates as an LC resonance circuit composed of the coil L and the two capacitors C1 and C2 when the transistor Tr1 is on. Therefore, the resonance frequency of the resonance circuit 11 differs between when the transistor Tr1 is off and when it is on. When the transistor Tr1 is off, the resonance frequency f1 of the resonance circuit 11 is expressed by the following equation.

Here, L is the inductance of the coil L, and C1 is the capacitance of the capacitor C1. On the other hand, when the transistor Tr1 is on, the resonance frequency f2 of the resonance circuit 11 is expressed by the following equation.

Here, C2 is the capacitance of the capacitor C2. If C1 = C2, the resonance frequency f2 is approximately 0.7 times the resonance frequency f1.

  The on / off control of the transistor Tr1 is performed by the second determination circuit 14. Details of the on / off control of the transistor Tr1 performed by the second determination circuit 14 will be described later.

  For example, the coil L is arranged in a path of a game ball such as a prize ball opening or a ball payout device so that the game ball passes through the inside of the coil L. Then, when the game ball passes through the coil L, the oscillation conditions of the resonance circuit 11 and the oscillation circuit 12 change, and the oscillation of the detection circuit 10 stops. On the other hand, when the game ball is sufficiently away from the coil L, the detection circuit 10 enters an oscillation state. For example, when the game ball is sufficiently separated from the coil L of the resonance circuit 11, the conductance gL of the resonance circuit 11 is smaller than the conductance gi of the oscillation circuit 12, and the Nyquist oscillation condition is satisfied. Is passing through the coil L, the inductance of the coil L and the capacitors C1 and C2 are set so that the conductance gL of the resonance circuit 11 is larger than the conductance gi of the oscillation circuit 12 and the Nyquist oscillation condition is not satisfied. The capacitance and the resistance value of the resistor R1 of the oscillation circuit 12 are set.

The oscillation circuit 12 is connected to an output terminal 11a provided on the high potential side of the resonance circuit 11, oscillates when the resonance circuit 11 enters an oscillation state, and amplifies the amplitude of oscillation of the resonance circuit 11. On the other hand, when the resonance circuit 11 is in the oscillation stop state, the oscillation circuit 12 also stops oscillation.
For this purpose, the oscillation circuit 12 includes four transistors Tr2 to Tr5, a constant current circuit I0, and a constant voltage circuit V0.

  The emitters of the PNP transistors Tr2 and Tr3 are each connected to a voltage source Vcc. The bases of the transistors Tr2 and Tr3 are connected to each other and further connected to the collector of the NPN transistor Tr4. Further, the collector of the transistor Tr2 is also connected to the collector of the transistor Tr4. The collector of the transistor Tr3 is connected to the output terminal 11a on the high voltage side of the resonance circuit 11. The base of the transistor Tr4 is connected between the voltage source Vcc and the output terminal 11a of the resonance circuit 11, and between the constant current circuit I0 and the constant voltage circuit V0 connected in series from the voltage source Vcc side. . Further, the emitter of the transistor Tr4 is grounded via the resistor R1.

  Further, the base of the PNP transistor Tr5 is connected between the emitter of the transistor Tr4 and the resistor R1, and the collector of the transistor Tr5 is connected to the voltage source Vcc via the resistor R2 and the output terminal of the oscillation circuit 12 12a. The emitter of the transistor Tr5 is grounded.

The negative terminal of the constant voltage circuit V0 is connected to the output terminal 11a of the resonance circuit 11, while
The positive terminal of the constant voltage circuit V0 is connected to the output terminal of the constant current circuit I0. The constant voltage circuit V0 keeps the DC bias voltage between the output terminal 11a of the resonance circuit 11 and the base of the transistor Tr4 constant.

  The input side terminal of the constant current circuit I0 is connected to the voltage source Vcc, while the output side terminal of the constant current circuit I0 is connected to the output terminal 11a of the resonance circuit 11 via the constant voltage circuit V0. I0 supplies a drive current to the coil L of the resonance circuit 11. As the constant current circuit I0 and the constant voltage circuit V0, any of various constant current circuits and constant voltage circuits can be used. For example, an oscillation circuit disclosed in Japanese Patent Application Laid-Open No. 2008-3003 The driving current circuit and the constant voltage circuit included in

  In the oscillation circuit 12, the emitter potential of the transistor Tr4 rises due to the voltage that is biased through the constant voltage circuit V0 and input to the base of the transistor Tr4, following the rise in the potential of the output terminal 11a of the resonance circuit 11. The collector current of the transistor Tr2 also increases due to the current determined by the emitter potential of the transistor Tr4 and the resistor R1. As the collector current increases, the collector current of the transistor Tr3 mirror-connected to the transistor Tr2 also increases, and the collector current of the transistor Tr3 is fed back to the output terminal on the high voltage side of the resonance circuit 11. Further, the base potential of the transistor Tr5 also rises due to the rise of the emitter potential of the transistor Tr4. As the base potential of the transistor Tr5 increases, the emitter potential of the transistor Tr5 also increases. By these circuit operations, the voltage at the output terminal 12a of the oscillation circuit 12 increases following the increase in the potential at the output terminal of the resonance circuit 11.

Similarly, even when the potential of the output terminal 11a of the resonance circuit 11 decreases, the current flowing through the transistors Tr2 and Tr3 also changes according to the potential input to the base of the transistor Tr4. Further, the base potential of the transistor Tr5 is determined by the emitter potential of the transistor Tr4, and the emitter potential of the transistor Tr5 also changes following the base potential of the transistor Tr5. Therefore, the voltage at the output terminal 12a of the oscillation circuit 12 also decreases following the decrease in the potential at the output terminal 11a of the resonance circuit 11.
Thus, while the resonance circuit 11 is in the oscillation state, the voltage at the output terminal 12 a of the oscillation circuit 12 oscillates at the resonance frequency of the resonance circuit 11. On the other hand, while the resonance circuit 11 is in the oscillation stop state, the voltage of the output terminal 12a of the oscillation circuit 12 becomes a constant voltage.

  The first determination circuit 13 is connected to the output terminal 12a of the oscillation circuit 12, and outputs different voltages depending on whether or not the amplitude of the voltage at the output terminal 12a is equal to or greater than a first threshold value. That is, the first determination circuit 13 determines whether the game ball is sufficiently far from the coil L of the resonance circuit 11 and the detection circuit 10 is in an oscillating state, and when the game ball passes through the coil L of the resonance circuit 11. Different voltages are output depending on whether 10 is in the oscillation stop state.

Similarly, the second determination circuit 14 is also connected to the output terminal 12a of the oscillation circuit 12, and the transistor Tr1 of the resonance circuit 11 is turned on depending on whether or not the amplitude of the voltage at the output terminal 12a is equal to or greater than the second threshold value.・ Switch off. To do. However, the second threshold value is set to a value closer to the average value of the voltage of the oscillation output from the oscillation circuit 12 than the first threshold value. Therefore, when an electromagnetic field having a frequency substantially equal to the resonance frequency f1 of the resonance circuit 11 is irradiated in a state where the game ball is close to the coil L of the resonance circuit 11, the output voltage from the first determination circuit 13 is switched. Before that, since the second determination circuit 14 turns on the transistor Tr1 of the resonance circuit 11, the resonance frequency of the resonance circuit 11 changes from f1 to f2, and the oscillation amplitude of the detection circuit 10 attenuates. Thereby, the malfunction of the proximity sensor 1 when such an electromagnetic field is irradiated is prevented.
Note that even when an electromagnetic field having a frequency substantially equal to the resonance frequency f2 of the resonance circuit 11 is irradiated in a state where the game ball is close to the coil L of the resonance circuit 11, the transistor Tr1 is off, so that the resonance circuit Since 11 does not resonate, the proximity sensor 1 does not malfunction.

  In the present embodiment, the first determination circuit 13 includes two transistors Tr6 and Tr7. The emitter of the NPN transistor Tr6 is connected to the output terminal 12a of the oscillation circuit 12 via the resistor R6, and the collector of the transistor Tr6 is connected to the base of the PNP transistor Tr7. The base of the transistor Tr6 is connected to the voltage source Vcc via the resistor R3 and the resistor R4 among the three resistors R3 to R5 connected in series between the voltage source Vcc and the ground.

The emitter of the transistor Tr7 is connected to the voltage source Vcc, and the collector of the transistor Tr7 is connected to the one end 13a on the high voltage side of the integrating circuit 131 composed of the resistor R8 and the capacitor C3 connected in parallel. The other end 13 b on the high voltage side of the integration circuit 131 becomes an output terminal of the first determination circuit 13.
The output terminal 13b of the first determination circuit 13 is output as an output circuit (not shown) for connecting the proximity sensor 1 to another device such as a control circuit, and a signal corresponding to the voltage of the output terminal 13b is output. Output from the circuit.

  The voltage of the output terminal 12a of the oscillation circuit 12 is higher than the first threshold voltage determined by the divided voltage of the sum of the resistance values of the resistors R3 and R4 and the resistance value of the resistor R5 and the base-emitter voltage of the transistor Tr6. If it is high, for example, when the oscillation circuit 12 is not oscillating, the transistor Tr6 is turned off. Note that the first threshold voltage is set to a value lower than the average voltage of the output terminal of the oscillation circuit 12. Therefore, the transistor Tr7 is also turned off, and as a result, no current flows to the integrating circuit 131, so that the output voltage of the first determination circuit 13 becomes relatively low.

  On the other hand, when the oscillation circuit 12 oscillates and the voltage at the output terminal 12a of the oscillation circuit 12 becomes lower than the first threshold voltage, that is, the oscillation amplitude of the detection circuit 10 is equal to the average value of the voltage at the output terminal 12a. When it becomes larger than the absolute value of the difference between the first threshold voltages, the transistor Tr6 is turned on. Therefore, the transistor Tr7 is also turned on, and as a result, a current flows into the integrating circuit 131, so that the output voltage of the first determination circuit 13 becomes relatively high. Further, since the output voltage of the first determination circuit 13 is smoothed by the integration circuit 131, the detection circuit 10 oscillates, and the amplitude thereof is the average voltage of the output terminal 12a of the oscillation circuit 12 and the first threshold voltage. While the difference is larger than the absolute value, the output voltage of the first determination circuit 13 is maintained at a relatively high value.

Similarly, the second determination circuit 14 includes two transistors Tr8 and Tr9. The emitter of the NPN transistor Tr8 is connected to the output terminal 12a of the oscillation circuit 12 via the resistor R7, and the collector of the transistor Tr8 is connected to the base of the PNP transistor Tr9. The base of the transistor Tr8 is connected to the voltage source Vcc via the resistor R3 among the three resistors R3 to R5 connected in series between the voltage source Vcc and the ground.
The emitter of the transistor Tr9 is connected to the voltage source Vcc, and the collector of the transistor Tr9 is connected to the one end 14a on the high voltage side of the integrating circuit 141 constituted by the resistor R9 and the capacitor C4 connected in parallel. The other end 14b on the high voltage side of the integration circuit 141 is connected to the base of the transistor Tr1 of the resonance circuit 11 via the resistor R10.

  The voltage of the output terminal 12a of the oscillation circuit 12 is higher than the second threshold voltage determined by the divided voltage of the resistance value of the resistor R3 and the sum of the resistance values of the resistors R4 and R5 and the base-emitter voltage of the transistor Tr8. If it is high, for example, when the oscillation circuit 12 is not oscillating, the transistor Tr8 is turned off. Therefore, the transistor Tr9 is also turned off, and as a result, no current flows to the integrating circuit 141, so that the output voltage of the second determination circuit 14 becomes relatively low.

  On the other hand, when the oscillation circuit 12 oscillates and the voltage at the output terminal of the oscillation circuit 12 becomes lower than the second threshold voltage, that is, the oscillation amplitude of the detection circuit 10 is equal to the average value of the voltage at the output terminal 12a. When the absolute value of the difference between the two threshold voltages is larger, the transistor Tr8 is turned on. Therefore, the transistor Tr9 is also turned on, and as a result, a current flows into the integrating circuit 141, so that the output voltage of the second determination circuit 14 becomes relatively high. Further, since the output voltage of the second determination circuit 14 is smoothed by the integration circuit 141, the oscillation circuit 12 oscillates, and the amplitude thereof is the average voltage of the output terminal 12a of the oscillation circuit 12 and the second threshold voltage. While the difference is larger than the absolute value, the output voltage of the second determination circuit 14 is maintained at a relatively high value, and the transistor Tr1 of the resonance circuit 11 is also kept on.

  Since the second threshold voltage depends on the voltage division of the resistance value of the resistor R3 and the sum of the resistance values of the resistors R4 and R5 as described above, the sum of the resistance values of the resistors R3 and R4 and the resistor R5 It becomes higher than the first threshold voltage depending on the partial pressure with respect to the resistance value. Therefore, the absolute value of the difference between the average voltage at the output terminal of the oscillation circuit 12 and the second threshold voltage is smaller than the absolute value of the difference between the average voltage at the output terminal of the oscillation circuit 12 and the first threshold voltage. Accordingly, when the oscillation circuit 12 starts oscillating from a state where the oscillation is stopped, the output voltage of the second determination circuit 14 is changed before the first determination circuit 13 and the resonance frequency of the resonance circuit 11 is switched. .

FIG. 2 is a timing chart showing the time change of the voltage of each part of the proximity sensor 1 when the electromagnetic field having the resonance frequency f1 of the resonance circuit 11 is not irradiated.
In FIG. 2, the horizontal axis of each graph represents time. The vertical axis of the top graph represents the distance between the game ball and the coil L of the resonance circuit 11. The vertical axis of each graph after the second from the top represents voltage. A line 201 represents a change over time in the distance between the game ball and the coil L of the resonance circuit 11. A waveform 202 represents an oscillation waveform of the voltage at the output terminal 12 a of the oscillation circuit 12. Waveforms 203 and 204 represent the waveform of the voltage at the output terminal 13b of the first determination circuit 13 and the waveform of the voltage at the output terminal 14b of the second determination circuit 14, respectively.

  Before the time t1, since the game ball is sufficiently far from the coil L of the resonance circuit 11, the detection circuit 10 is in an oscillation state, and the voltage at the output terminal 12a of the oscillation circuit 12 is also oscillating. Since the amplitude of the voltage is larger than the absolute value of the difference between the average value of the voltage at the output terminal 12a of the oscillation circuit 12 and the first threshold voltage Th1, the output voltage of the first determination circuit 13 and the second determination circuit 14 These output voltages are all relatively high voltages indicating ON.

  After time t1, as the game ball approaches the coil L of the resonance circuit 11, the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 gradually decreases. At time t2, the amplitude becomes smaller than the absolute value of the difference between the average value of the voltage at the output terminal 12a of the oscillation circuit 12 and the first threshold voltage Th1. As a result, the output voltage of the first determination circuit 13 decreases to a relatively low voltage indicating that it is off. On the other hand, the amplitude of the voltage at the output terminal of the oscillation circuit 12 is larger than the absolute value of the difference between the average value of the voltage at the output terminal of the oscillation circuit 12 and the second threshold voltage Th2. The output voltage of 14 is maintained at a relatively high voltage.

  Thereafter, as the game ball gets closer to the coil L of the resonance circuit 11, the amplitude of the voltage at the output terminal 12 a of the oscillation circuit 12 is further reduced. At time t3, the amplitude becomes smaller than the absolute value of the difference between the average value of the voltage at the output terminal 12a of the oscillation circuit 12 and the second threshold voltage Th2. As a result, the output voltage of the second determination circuit 14 also decreases to a relatively low voltage indicating that it is off. Therefore, the transistor Tr1 of the resonance circuit 11 is turned off, and the capacitor C2 does not contribute to the resonance of the resonance circuit 11, so that the resonance frequency of the resonance circuit 11 is switched from f2 to f1. As the resonance frequency changes, the oscillation frequency of the detection circuit 10 also increases.

  After that, as the game ball gets closer to the coil L of the resonance circuit 11, the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 is further reduced, and the detection circuit 10 is in an oscillation stop state at time t4. When the game ball begins to leave the coil L of the resonance circuit 11, the detection circuit 10 resumes oscillation at time t5.

  Thereafter, as the game ball moves further away from the coil L of the resonance circuit 11, the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 gradually increases, and at time t6, the amplitude is equal to the voltage at the output terminal of the oscillation circuit 12. It becomes larger than the absolute value of the difference between the average value and the second threshold voltage Th2. As a result, the output voltage of the second determination circuit 14 also rises to a relatively high voltage. Therefore, the transistor Tr1 of the resonance circuit 11 is turned on and the capacitor C2 contributes to the resonance of the resonance circuit 11, so that the resonance frequency of the resonance circuit 11 decreases from f1 to f2. As the resonance frequency changes, the oscillation frequency of the detection circuit 10 also decreases.

Thereafter, as the game ball moves further away from the coil L of the resonance circuit 11, the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 further increases. At time t7, the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 increases. It becomes larger than the absolute value of the difference between the average value and the first threshold voltage Th1. As a result, the output voltage of the first determination circuit 13 also rises to a relatively high voltage.
In this way, each time the game ball passes through the coil L of the resonance circuit 11, the output voltage from the first determination circuit 13 temporarily decreases from a relatively high voltage to a relatively low voltage, and then again relative. Return to a higher voltage. Therefore, a circuit that counts game balls passing through the coil L of the proximity sensor 1 such as a control circuit (not shown) of the game machine checks the change in the output voltage from the first determination circuit 13 to thereby determine the game ball. Can be counted.

FIG. 3 is a timing chart showing the time change of the voltage of each part of the proximity sensor 1 when the electromagnetic field having the resonance frequency f1 of the resonance circuit 11 is irradiated.
In FIG. 3, the horizontal axis of each graph represents time. The vertical axis of the top graph represents the distance between the game ball and the coil L of the resonance circuit 11. The vertical axis of each graph after the second from the top represents voltage. A line 301 represents a change over time in the distance between the game ball and the coil L of the resonance circuit 11. A waveform 302 represents an oscillation waveform of the voltage at the output terminal 12 a of the oscillation circuit 12. Waveforms 303 and 304 represent the waveform of the voltage at the output terminal 13b of the first determination circuit 13 and the waveform of the voltage at the output terminal 14b of the second determination circuit 14, respectively. Furthermore, a waveform 305 shown at the bottom represents the presence or absence of an electromagnetic field having the same frequency as the resonance frequency f 1 in the vicinity of the resonance circuit 11.

  In this example, the electromagnetic field is applied to the resonance circuit 11 from time t1 to time t5, and the coil L of the resonance circuit 11 is stopped so that the game ball stops oscillation of the detection circuit 10 from time t1 to time t6. Is located in the vicinity of.

  Between time t1 and time t2, the detection circuit 10 oscillates despite the presence of the game ball in the vicinity due to the electromagnetic field irradiation, and the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 gradually increases. At time t2, the amplitude becomes greater than the absolute value of the difference between the average value of the voltage at the output terminal 12a of the oscillation circuit 12 and the second threshold voltage Th2. As a result, the output voltage of the second determination circuit 14 also rises to a relatively high voltage. Therefore, the transistor Tr1 of the resonance circuit 11 is turned on and the capacitor C2 contributes to the resonance of the resonance circuit 11, so that the resonance frequency of the resonance circuit 11 decreases from f1 to f2. Due to the change in the resonance frequency, the frequency of the electromagnetic field and the resonance frequency of the resonance circuit 11 do not coincide with each other, so that the oscillation of the detection circuit 10 gradually weakens after time t2.

  At time t3, the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 becomes smaller than the absolute value of the difference between the average value of the voltage at the output terminal of the oscillation circuit 12 and the second threshold voltage Th2. As a result, the output voltage of the second determination circuit 14 also decreases to a relatively low voltage. Therefore, the transistor Tr1 of the resonance circuit 11 is turned off and the capacitor C2 does not contribute to the resonance of the resonance circuit 11, so that the resonance frequency of the resonance circuit 11 returns from f2 to f1. As a result, the resonance circuit 11 resonates with the electromagnetic field, so that the amplitude of the output voltage of the oscillation circuit 12 also begins to increase again after time t3.

  However, at time t4, similarly to time t2, the amplitude of the output voltage of the oscillation circuit 12 becomes larger than the absolute value of the difference between the average value of the voltage at the output terminal 12a of the oscillation circuit 12 and the second threshold voltage Th2. Therefore, the output voltage of the second determination circuit 14 also rises to a relatively high voltage, the transistor Tr1 of the resonance circuit 11 is turned on again, and the resonance frequency of the resonance circuit 11 decreases from f1 to f2.

  Thus, while the electromagnetic field is applied to the resonance circuit 11, the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 is equal to the average value of the voltage at the output terminal 12a of the oscillation circuit 12 and the first threshold voltage Th1. Therefore, the output voltage of the first determination circuit 13 is maintained at a relatively low voltage. Then, an increase in the amplitude of the output voltage of the oscillation circuit 12 → a decrease in the resonance frequency of the resonance circuit 11 → a decrease in the amplitude of the output voltage of the oscillation circuit 12 → an increase in the resonance frequency of the resonance circuit 11 → the amplitude of the output voltage of the oscillation circuit 12. Will be repeated.

  When the electromagnetic field is no longer applied to the resonance circuit 11 at time t5, the oscillation of the detection circuit 10 is also stopped thereafter. Then, after the game ball starts to move away from the coil L of the resonance circuit 11, the detection circuit 10 resumes oscillation at time t6. Thereafter, as the distance between the game ball and the coil L of the resonance circuit 11 increases, the amplitude of the output voltage of the oscillation circuit 12 gradually increases, and at time t7, the amplitude of the output voltage of the oscillation circuit 12 increases. Is greater than the absolute value of the difference between the average value of the output terminal voltages and the first threshold voltage Th1. As a result, the output voltage of the first determination circuit 13 also rises to a relatively high voltage.

  Thus, the output voltage of the first determination circuit 13 does not change regardless of whether or not the electromagnetic field having the same frequency as the resonance frequency f1 is irradiated on the resonance circuit 11. Therefore, it turns out that this proximity sensor 1 does not malfunction by irradiation of such an electromagnetic field.

  As described above, in the proximity sensor, when the detection circuit starts oscillating from the oscillation stopped state, the resonance frequency of the resonance circuit is switched before the output voltage of the proximity sensor is switched. Therefore, even if this proximity sensor is irradiated with an electromagnetic field having the same frequency as one of the resonance frequencies of the resonance circuit, the resonance circuit will not resonate before the output voltage changes. The influence on the output voltage can be suppressed. Therefore, this proximity sensor can suppress malfunction caused by such electromagnetic field irradiation.

  According to the modification, each of the first threshold voltage and the second threshold voltage may be set to a voltage higher than the average value of the voltages at the output terminals of the oscillation circuit. However, also in this case, the first value is such that the absolute value of the difference between the average value and the second threshold voltage is smaller than the absolute value of the difference between the average value and the first threshold voltage. The threshold voltage and the second threshold voltage are set.

  FIG. 4 is a circuit diagram of the proximity sensor 2 according to this modification. The proximity sensor 2 according to the modification also includes a detection circuit 10, a first determination circuit 23, and a second determination circuit 24. The detection circuit 10 includes a resonance circuit 11 and an oscillation circuit 12. The proximity sensor 2 shown in FIG. 4 is different in the configuration of the first determination circuit 23 and the second determination circuit 24 from the proximity sensor 1 shown in FIG. Therefore, hereinafter, the first determination circuit 23, the second determination circuit 24, and related parts will be described. For details of the detection circuit 10, refer to the description of the above embodiment.

  In this modification, the first determination circuit 23 includes a comparator CMP1 and an integration circuit 231. The voltage output from the output terminal 12a of the oscillation circuit 12 is input to the positive input terminal of the comparator CMP1. On the other hand, the negative input terminal of the comparator CMP1 is connected to the voltage source Vcc via the resistor R3 among the three resistors R3 to R5 connected in series between the voltage source Vcc and the ground. The output terminal of the comparator CMP1 is connected via a resistor R6 to one end 23a on the high voltage side of an integrating circuit 231 configured by a resistor R7 and a capacitor C3 connected in parallel. The other end 23 b on the high voltage side of the integration circuit 231 becomes an output terminal of the first determination circuit 23.

  When the voltage of the output terminal 12a of the oscillation circuit 12 is lower than the first threshold voltage determined by dividing the resistance value of the resistor R3 and the sum of the resistance values of the resistors R4 and R5, for example, the detection circuit 10 When not oscillating, the output voltage of the comparator CMP1 is relatively low. For this reason, since no current flows to the integrating circuit 231, the output voltage of the first determining circuit 23 is relatively low.

  On the other hand, when the detection circuit 10 oscillates and the voltage of the output terminal 12a of the oscillation circuit 12 becomes higher than the first threshold voltage, the output voltage of the comparator CMP1 becomes relatively high. Therefore, current flows into the integration circuit 231 and the output voltage of the first determination circuit 23 becomes relatively high. Further, since the output voltage of the first determination circuit 23 is smoothed by the integration circuit 231, the oscillation circuit 12 oscillates, and the amplitude thereof is the difference between the average voltage of the output terminal of the oscillation circuit 12 and the first threshold voltage. The output voltage of the first determination circuit 23 is maintained at a relatively high value while being larger than the absolute value of.

  Similarly, the second determination circuit 24 includes a comparator CMP2 and an integration circuit 241. The voltage output from the output terminal 12a of the oscillation circuit 12 is input to the positive input terminal of the comparator CMP2. On the other hand, the negative input terminal of the comparator CMP2 is connected to the voltage source Vcc via the resistor R3 and the resistor R4. The output terminal of the comparator CMP2 is connected via a resistor R8 to one end 24a on the high voltage side of the integrating circuit 241 constituted by a resistor R9 and a capacitor C4 connected in parallel. The other end 24b on the high voltage side of the integration circuit 241 is connected to the base of the transistor Tr1 of the resonance circuit 11 via the resistor R10.

  When the voltage of the output terminal 12a of the oscillation circuit 12 is lower than the second threshold voltage determined by dividing the sum of the resistance values of the resistors R3 and R4 and the resistance value of the resistor R5, for example, the detection circuit 10 When not oscillating, the output voltage of the comparator CMP2 is relatively low. For this reason, since no current flows to the integrating circuit 241, the output voltage of the second determining circuit 24 is relatively low.

  On the other hand, when the detection circuit 10 oscillates and the voltage of the output terminal 12a of the oscillation circuit 12 becomes higher than the second threshold voltage, the output voltage of the comparator CMP2 becomes relatively high. For this reason, a current flows into the integrating circuit 241, and the output voltage of the second determining circuit 24 becomes relatively high. Further, since the output voltage of the second determination circuit 24 is smoothed by the integration circuit 241, the oscillation circuit 12 oscillates, and the amplitude thereof is the difference between the average voltage of the output terminal of the oscillation circuit 12 and the second threshold voltage. The output voltage of the second determination circuit 24 is maintained at a relatively high value while the transistor Tr1 of the resonance circuit 11 is kept on.

  Further, since the second threshold voltage depends on the voltage division of the sum of the resistance values of the resistors R3 and R4 and the resistance value of the resistor R5, the sum of the resistance values of the resistor R3 and the resistors R4 and R5. It becomes lower than the first threshold voltage depending on the partial pressure. Therefore, the absolute value of the difference between the average voltage at the output terminal of the oscillation circuit 12 and the second threshold voltage is smaller than the absolute value of the difference between the average voltage at the output terminal of the oscillation circuit 12 and the first threshold voltage. Therefore, as in the above embodiment, when the oscillation starts from the state where the detection circuit 10 stops oscillating, the output voltage of the second determination circuit 24 changes before the first determination circuit 23. The resonance frequency of the resonance circuit 11 is switched.

FIG. 5 is a timing chart showing the time change of the voltage of each part of the proximity sensor 2 when the electromagnetic field having the resonance frequency f1 of the resonance circuit 11 is not irradiated according to the modification.
In FIG. 5, the horizontal axis of each graph represents time. The vertical axis of the top graph represents the distance between the game ball and the coil L of the resonance circuit 11. The vertical axis of each graph after the second from the top represents voltage. A line 501 represents a change over time in the distance between the game ball and the coil L of the resonance circuit 11. A waveform 502 represents an oscillation waveform of the voltage at the output terminal 12 a of the oscillation circuit 12. Waveforms 503 and 504 represent the waveform of the voltage at the output terminal 23b of the first determination circuit 23 and the waveform of the voltage at the output terminal 24b of the second determination circuit 24, respectively.

  As shown by the line 501, since the game ball is sufficiently far from the coil L of the resonance circuit 11 before the time t 1, the detection circuit 10 is in an oscillation state, and as shown by the waveform 502, The voltage at the output terminal 12a also oscillates. Since the amplitude of the voltage is larger than the absolute value of the difference between the average value of the voltage at the output terminal 12a of the oscillation circuit 12 and the first threshold voltage Th1, the first determination circuit is shown in the waveforms 503 and 504. Both the output voltage 23 and the output voltage of the second determination circuit 24 are relatively high voltages indicating that the output voltage is on.

  After time t1, as the game ball approaches the coil L of the resonance circuit 11, the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 gradually decreases. At time t2, the amplitude becomes smaller than the absolute value of the difference between the average value of the voltage at the output terminal 12a of the oscillation circuit 12 and the first threshold voltage Th1. As a result, the output voltage of the first determination circuit 23 drops to a relatively low voltage indicating that it is off. On the other hand, the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 is larger than the absolute value of the difference between the average value of the voltage at the output terminal 12a of the oscillation circuit 12 and the second threshold voltage Th2. The output voltage of the determination circuit 24 is maintained at a relatively high voltage.

  Thereafter, as the game ball gets closer to the resonance circuit 11, the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 is further reduced. At time t3, the amplitude becomes smaller than the absolute value of the difference between the average value of the voltage at the output terminal 12a of the oscillation circuit 12 and the second threshold voltage Th2. As a result, the output voltage of the second determination circuit 24 also decreases to a relatively low voltage indicating that it is off. Therefore, the transistor Tr1 of the resonance circuit 11 is turned off, and the capacitor C2 does not contribute to the resonance of the resonance circuit 11, so that the resonance frequency of the resonance circuit 11 increases from f2 to f1. As the resonance frequency changes, the oscillation frequency of the detection circuit 10 also increases.

  After that, as the game ball gets closer to the coil L of the resonance circuit 11, the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 is further reduced, and the detection circuit 10 is in an oscillation stop state at time t4. When the game ball begins to leave the coil L of the resonance circuit 11, the detection circuit 10 resumes oscillation at time t5.

  Thereafter, as the game ball moves further away from the coil L of the resonance circuit 11, the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 gradually increases, and at time t6, the amplitude is the voltage at the output terminal 12a of the oscillation circuit 12. Is greater than the absolute value of the difference between the average value and the second threshold voltage Th2. As a result, the output voltage of the second determination circuit 24 also rises to a relatively high voltage. Therefore, the transistor Tr1 of the resonance circuit 11 is turned on and the capacitor C2 contributes to the resonance of the resonance circuit 11, so that the resonance frequency of the resonance circuit 11 decreases from f1 to f2. As the resonance frequency changes, the oscillation frequency of the detection circuit 10 also decreases.

  Thereafter, as the game ball moves further away from the coil L of the resonance circuit 11, the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 further increases. At time t7, the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 increases. It becomes larger than the absolute value of the difference between the average value and the first threshold voltage Th1. As a result, the output voltage of the first determination circuit 23 also rises to a relatively high voltage.

  Thus, also in this modification, every time the game ball passes in the vicinity of the resonance circuit 11, the output voltage from the first determination circuit 23 temporarily decreases from a relatively high voltage to a relatively low voltage, Thereafter, the voltage returns again to a relatively high voltage.

FIG. 6 is a timing chart showing the time change of the voltage of each part of the proximity sensor 1 when the electromagnetic field having the resonance frequency f1 of the resonance circuit 11 is irradiated.
In FIG. 6, the horizontal axis of each graph represents time. The vertical axis of the top graph represents the distance between the game ball and the coil L of the resonance circuit 11. The vertical axis of each graph after the second from the top represents voltage. A line 601 represents a change over time in the distance between the game ball and the coil L of the resonance circuit 11. A waveform 602 represents an oscillation waveform of the voltage at the output terminal 12 a of the oscillation circuit 12. Waveforms 603 and 604 represent the waveform of the voltage at the output terminal 23b of the first determination circuit 23 and the waveform of the voltage at the output terminal 24b of the second determination circuit 24, respectively. Furthermore, a waveform 605 shown at the bottom represents the presence or absence of an electromagnetic field having the same frequency as the resonance frequency f1 in the vicinity of the resonance circuit 11.

  In this example, the electromagnetic field is applied to the resonance circuit 11 from time t1 to time t5, and the coil L of the resonance circuit 11 is stopped so that the game ball stops oscillation of the detection circuit 10 from time t1 to time t6. Is located in the vicinity of.

  Between time t1 and time t2, the detection circuit 10 oscillates despite the presence of the game ball in the vicinity due to the electromagnetic field irradiation, and the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 gradually increases. At time t2, the amplitude becomes larger than the absolute value of the difference between the average value of the voltage at the output terminal 12a of the oscillation circuit 12 and the second threshold voltage Th2. As a result, the output voltage of the second determination circuit 24 also rises to a relatively high voltage. Therefore, the transistor Tr1 of the resonance circuit 11 is turned on and the capacitor C2 contributes to the resonance of the resonance circuit 11, so that the resonance frequency of the resonance circuit 11 decreases from f1 to f2. Due to the change in the resonance frequency, the frequency of the electromagnetic field and the resonance frequency of the resonance circuit 11 do not coincide with each other, so that the oscillation of the detection circuit 10 gradually weakens after time t2.

  At time t3, the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 becomes smaller than the absolute value of the difference between the average value of the voltage at the output terminal 12a of the oscillation circuit 12 and the second threshold voltage Th2. As a result, the output voltage of the second determination circuit 24 also decreases to a relatively low voltage. Therefore, the transistor Tr1 of the resonance circuit 11 is turned off and the capacitor C2 does not contribute to the resonance of the resonance circuit 11, so that the resonance frequency of the resonance circuit 11 returns from f2 to f1. As a result, the resonance circuit 11 resonates with the electromagnetic field, so that the amplitude of the output voltage of the oscillation circuit 12 also begins to increase again after time t3.

  However, at time t4, similarly to time t2, the amplitude of the voltage at the output terminal 12a of the oscillation circuit 12 is greater than the absolute value of the difference between the average value of the voltage at the output terminal 12a of the oscillation circuit 12 and the second threshold voltage Th2. Therefore, the output voltage of the second determination circuit 24 also rises to a relatively high voltage, the transistor Tr1 of the resonance circuit 11 is turned on, and the resonance frequency of the resonance circuit 11 decreases from f1 to f2.

  Thus, while the electromagnetic field is applied to the resonance circuit 11, the amplitude of the output voltage of the oscillation circuit 12 is the absolute difference between the average value of the voltage at the output terminal 12a of the oscillation circuit 12 and the first threshold voltage Th1. Therefore, the output voltage of the first determination circuit 23 is maintained at a relatively low voltage. Then, an increase in the amplitude of the output voltage of the oscillation circuit 12 → a decrease in the resonance frequency of the resonance circuit 11 → a decrease in the amplitude of the output voltage of the oscillation circuit 12 → an increase in the resonance frequency of the resonance circuit 11 → the amplitude of the output voltage of the oscillation circuit 12. Will be repeated.

  When the electromagnetic field is no longer applied to the resonance circuit 11 at time t5, the oscillation of the detection circuit 10 is also stopped thereafter. Then, after the game ball starts to move away from the coil L of the resonance circuit 11, the detection circuit 10 resumes oscillation at time t6. Thereafter, as the distance between the game ball and the coil L of the resonance circuit 11 increases, the amplitude of the output voltage of the oscillation circuit 12 gradually increases, and at time t7, the amplitude of the output voltage of the oscillation circuit 12 increases. Is greater than the absolute value of the difference between the average value of the voltages at the output terminal 12a and the first threshold voltage Th1. As a result, the output voltage of the first determination circuit 23 also rises to a relatively high voltage.

  Thus, the output voltage of the first determination circuit 13 does not change regardless of whether or not the electromagnetic field having the same frequency as the resonance frequency f1 is irradiated on the resonance circuit 11. Therefore, it can be seen that the proximity sensor 2 according to this modification also does not malfunction due to irradiation of such an electromagnetic field.

  According to another modification, the resonance circuit may be an LC resonance circuit in which one capacitor and two coils are connected in parallel. In this case, a transistor that is on / off controlled in accordance with the output voltage from the second determination circuit may be connected in series with any one of the coils.

  FIG. 7 is a circuit diagram of the resonance circuit 21 according to this modification. The resonance circuit 21 includes two coils L1 and L2 and a capacitor C that are connected in parallel to each other. Further, the resonance circuit 21 includes an NPN transistor Tr1 that is an example of a switch that is connected in parallel with the capacitor C and the coil L1 and connected in series with the coil L2. One ends of the coils L 1 and L 2 and the capacitor C are connected to the output terminal on the high voltage side of the resonance circuit 21. On the other hand, the other ends of the coil L1 and the capacitor C are grounded. Similarly, the other end of the coil L2 is grounded to the collector of the transistor Tr1, and the emitter of the transistor Tr1 is grounded. Note that the connection positions of the transistor Tr1 and the coil L2 may be interchanged.

ここで、L1は、コイルL1のインダクタンスであり、Cは、コンデンサCの静電容量である。一方、トランジスタTr1がオンのとき、共振回路２１の共振周波数f2は次式で表される。

ここで、L2は、コイルL2のインダクタンスである。もし、L1=L2であれば、共振周波数f2は、共振周波数f1の略1.4倍となる。
このように、この変形例でも、共振回路２１は、第２判定回路からの出力電圧に応じて共振周波数を切り替えることができる。 The resonant circuit 21 operates as an LC resonant circuit composed of the coil L1 and the capacitor C when the transistor Tr1 is off. On the other hand, the resonance circuit 21 operates as an LC resonance circuit composed of two coils L1 and L2 and a capacitor C when the transistor Tr1 is on. Therefore, the oscillation frequency of the resonant circuit 21 changes between when the transistor Tr1 is off and when it is on. When the transistor Tr1 is off, the resonance frequency f1 of the resonance circuit 21 is expressed by the following equation.

Here, L1 is the inductance of the coil L1, and C is the capacitance of the capacitor C. On the other hand, when the transistor Tr1 is on, the resonance frequency f2 of the resonance circuit 21 is expressed by the following equation.

Here, L2 is the inductance of the coil L2. If L1 = L2, the resonance frequency f2 is approximately 1.4 times the resonance frequency f1.
Thus, also in this modification, the resonance circuit 21 can switch the resonance frequency according to the output voltage from the second determination circuit.

  According to still another modification, the resonance circuit of the proximity sensor may include three or more capacitors connected in parallel with the coil. Other than one of these capacitors, like the capacitor C2 of the resonance circuit 11 shown in FIG. 1, it may be connected in series with the transistor. A transistor connected in series with one of the capacitors of the resonance circuit is turned on / off according to the amplitude of the voltage at the output terminal of the oscillation circuit by a determination circuit similar to the second determination circuit shown in FIG. It may be controlled. In this case, the threshold voltages at which the respective determination circuits turn on the transistors are different from each other, and the absolute value of the difference between the average value of the output voltages of the oscillation circuit and the threshold voltage gives the output of the proximity sensor itself. The absolute value of the difference between the first threshold voltage and the average value of the output voltage of the oscillation circuit may be set to be smaller. As a result, when the detection circuit starts to oscillate as the game ball moves away from the resonance circuit from the state where the game ball is close to the resonance circuit and the oscillation of the detection circuit is stopped, the output of the detection circuit is generated by the oscillation. As the voltage amplitude increases, the resonance frequency is switched in three or more stages. For this reason, the proximity sensor according to this modification can suppress malfunction due to the electromagnetic field even when the frequency of the irradiated electromagnetic field can be switched in two stages.

  FIG. 8 is an external perspective view of the proximity sensor 108 according to the above-described embodiment or modification. The proximity sensor 108 has the circuit shown in the above-described embodiment or modification on a substrate (not shown) provided in the resin casing 31. A passage hole 32 through which a game ball can pass is formed on one end side of the housing 31, and a resonance circuit coil is provided so as to cover the periphery of the passage hole 32. That is, when the game ball passes through the passage hole 32, the game ball also passes through the inside of the coil of the resonance circuit.

  FIG. 9 is a schematic perspective view of a gaming machine on which the proximity sensor according to the above embodiment or modification is mounted. As shown in FIG. 9, the gaming machine 100 is provided in a large area from the upper part to the central part, and includes a gaming board 101 that is a gaming machine main body, and a ball receiving part 102 that is disposed below the gaming board 101. And an operation unit 103 having a handle, and a display device 104 provided substantially at the center of the game board 101.

  A rail 105 is provided on the side of the game board 101. On the game board 101, a plurality of obstacle nails 106 that define a plurality of paths through which game balls flow and at least one winning device 107 are provided on any of the paths. In each winning device 107, in order to detect that the game ball has entered the winning device 107, the proximity sensor 108 is positioned so that the passage hole 32 is positioned on the path of the gaming ball that has entered the winning device 107. Be placed.

  On the back side of the gaming machine 100, for example, a main control circuit (not shown) for controlling the entire gaming machine 100, and various units related to game effects such as the display device 104 and a speaker (not shown) are controlled. A sub-control circuit (not shown) is arranged.

  The operation unit 103 launches a game ball with a predetermined force from a launching device (not shown) according to the amount of rotation of the handle by the player's operation. The launched game ball moves upward along the rail 105 and falls between a number of obstacle nails 106. When the proximity sensor 108 detects that a game ball has entered any winning device 107, a main control circuit (not shown) provided on the back of the gaming board 101 causes the winning device 107 containing the game ball to enter. A predetermined number of game balls corresponding to the above are paid out to the ball receiving portion 102 via a ball payout device (not shown).

  As described above, those skilled in the art can make various modifications in accordance with the embodiment to be implemented within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1, 2 Proximity sensor 10 Detection circuit 11, 21 Resonance circuit 12 Oscillation circuit 13, 23 1st determination circuit 14, 24 2nd determination circuit 15 Output circuit 100 Game machine 101 Game board 102 Ball receiving part 103 Operation part 104 Display apparatus 105 Rail 106 Obstacle nail 107 Winning device 108 Proximity sensor
L, L1, L2 coil
C, C1 to C3 capacitors
R1 ~ R10 resistance
CMP1, CMP2 comparator
Tr1 to Tr9 transistors

Claims (4)

A detection circuit that oscillates at any of a plurality of resonance frequencies, and the amplitude of the oscillation decreases as the distance from the object to be detected decreases;
A first voltage is output when connected to the detection circuit and the amplitude of the oscillation of the detection circuit is greater than a first threshold, while the amplitude of the oscillation of the detection circuit is greater than the first threshold A first determination circuit that outputs a second voltage different from the first voltage when it is small;
The resonance frequency of the detection circuit is set to the first of the plurality of resonance frequencies when the amplitude of the oscillation of the detection circuit is greater than a second threshold that is smaller than the first threshold. On the other hand, when the amplitude of the oscillation of the detection circuit is smaller than the second threshold, the resonance frequency of the detection circuit is different from the first resonance frequency of the plurality of resonance frequencies. A second determination circuit having a second resonance frequency;
Proximity sensor. The detection circuit includes:
A first coil;
A first capacitor connected in parallel with the first coil;
A second capacitor connected in parallel with the first coil and the first capacitor;
A switching element connected in parallel with the first coil and the first capacitor, and connected in series with the second capacitor, and switching whether to energize the second capacitor;
When the switching element is turned off and the second capacitor is not energized, the detection circuit oscillates at the first resonance frequency, while when the switching element is turned on and energizes the second capacitor. The detection circuit oscillates at the second resonance frequency;
When the amplitude of the oscillation of the detection circuit is smaller than the second threshold value, the second determination circuit turns off the switching element to stop energization of the second capacitor, while the detection circuit 2. The proximity sensor according to claim 1, wherein the second determination circuit turns on the switching element to energize the second capacitor when an oscillation amplitude of the second oscillation circuit is greater than the second threshold value. The detection circuit includes:
A first coil;
A first capacitor connected in parallel with the first coil;
A second coil connected in parallel with the first coil and the first capacitor;
A switching element connected in parallel with the first coil and the first capacitor, and connected in series with the second coil, and switching whether to energize the second coil;
When the switching element is turned off and the second coil is not energized, the detection circuit oscillates at the first resonance frequency, while when the switching element is turned on and energizes the second coil The detection circuit oscillates at the second resonance frequency;
When the amplitude of the oscillation of the detection circuit is smaller than the second threshold, the second determination circuit turns off the switching element to stop energization of the second coil, while the detection circuit 2. The proximity sensor according to claim 1, wherein the second determination circuit turns on the switching element to energize the second coil when the oscillation amplitude of the second oscillation circuit is larger than the second threshold value. A gaming machine body,
A winning device provided on the front surface of the gaming machine main body and provided on any of a plurality of paths along which the game ball can flow down,
The proximity sensor according to any one of claims 1 to 3, which detects that a game ball has entered the winning device.
A ball payout device for paying out game balls;
When a game ball that has entered the winning device is detected by the proximity sensor, a control unit that causes the ball payout device to pay out a predetermined number of game balls;
A gaming machine having.

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