JP3134375B2 - Detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detection device for detecting the proximity of a metal object or an object having a metal film in a non-contact manner.

[0002]

2. Description of the Related Art Conventionally, as this type of detection apparatus, there has been known an apparatus which detects an object by using a change in eddy current.
As shown in FIG. 5, an oscillation coil L in a high-frequency oscillation circuit of several tens of kHz is used as a detection unit, and a subject K uses this oscillation coil L
When receiving the magnetic field generated from the eddy current, an eddy current flows in the subject K.
Since the generation of the eddy current causes a current loss and consumes the oscillation energy of the high-frequency oscillation circuit, the oscillation is normally stopped, and the presence of the subject K is detected from the oscillation state.

[0003]

However, in the detection device, since it is necessary to provide the oscillation coil L having a relatively large size beside the passage of the subject K, the whole device cannot be designed to be compact. There was such a problem. In addition, since the detection device includes the oscillation coil L and the circuit board electrically connected to the oscillation coil L, the number of components is large, and therefore, there is a problem that reliability is low. . The reliability is also low in terms of electrical connection between the oscillation coil L and the circuit board. Furthermore, there is a problem that assembly workability is poor because of the large number of parts. In particular, the assembly of the oscillation coil L to the circuit board is relatively difficult, and the workability of the assembly is poor.

The detection apparatus of the present invention has been made to solve the above problems and to make the whole apparatus compact while improving the reliability and the assembling workability, and has the following configuration. .

[0005]

According to the present invention, there is provided a detecting device which comprises a detecting portion and a circuit board, and detects the proximity of an object made of metal or having a metal coating in a non-contact manner. The circuit board is provided with a through hole through which a subject passes, and a coil is formed in a wiring pattern around the through hole, the coil is used as the detection unit, and oscillation is performed using an inductance component of the coil. An oscillation circuit;
The gist is that a switching circuit which is turned on / off according to the oscillation state of the oscillation circuit is provided on the circuit board.

Here, the wiring pattern forming the coil may be formed on both the front and back surfaces of the circuit board.

[0007]

In the detection device of the present invention having the above-described configuration, when the metal or the object having the metal coating does not exist in the through hole on the circuit board, the oscillation circuit is formed around the through hole. It oscillates using the inductance component of the coil as the detection unit constituted by the wiring pattern. On the other hand, when the subject passes through the through hole and the magnetic flux formed by the coil passes through the subject, the oscillation energy is lost mainly due to eddy current loss, the oscillation state of the oscillation circuit changes, and the normal oscillation stops. I do. The switching circuit is turned on and off according to the oscillation state of the oscillation circuit, and outputs a signal to the outside according to the presence or absence of the subject.

Here, since the coil as the detecting section is formed by a wiring pattern around the through hole on the circuit board, the detecting section is integrated with the circuit board.
Moreover, the size of the entire device including the coil is limited only by the size of the circuit board itself.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to further clarify the configuration and operation of the present invention described above, a preferred embodiment of the detecting device of the present invention will be described below. FIG. 1 is an exploded perspective view of a pachinko ball detection device as an embodiment in which a subject is a pachinko ball, FIG. 2 is a perspective view of an assembled state of the pachinko ball detection device, FIG. 3 is a circuit diagram of the pachinko ball detection device, It is.

In this embodiment, the pachinko ball detection device 1
A well-known microprocessing unit (hereinafter referred to as an MPU) that is used for detecting a safe ball dropped into a winning opening or a payout ball at a pachinko machine and performs various processes using an output signal of the pachinko ball detection device 1. ) 2 input ports P
B1.

As shown in FIG. 1, a pachinko ball detecting device 1
Has an upper lid 11 and a lower box 12, and has a circuit board 13 inside a combination of both members. The upper lid 11 is provided with a pair of substantially L-shaped L-shaped pieces 21 and 22 and a pair of substantially T-shaped T-shaped pieces 23 (only one side is shown in the figure). A pair of protruding pieces 31 and 32 respectively engaging with the L-shaped pieces 21 and 22 and a pair of
A pair of projecting pieces 33 and 34 (only one side is shown in the figure) are provided. The upper lid 11 and the lower box 12 are combined by one-touch by the engagement of the pieces to form a cubic box. The upper lid 11 and the lower box 12
Are provided with through holes 41 and 42 through which the pachinko balls P pass.

One end of the circuit board 13 protrudes out of a box composed of the upper lid 11 and the lower box 12, and is used as terminals T1 and T2 for connection to the outside. Electronic components such as the coil L1 and the transistors Tr1 and Tr2 shown in FIG. 3 are assembled on the circuit board 13. As shown in FIG. 1, the circuit board 13 is provided with a through hole 51 of the pachinko ball P at a position communicating with the through holes 41 and 42 when the upper lid 11 and the lower box 12 are combined. The coil L1 is composed of a wiring pattern 52 of a total of two turns, one turn each for the front and back surfaces formed around the through hole 51. The back surface of the double-sided board is a Faraday shield to prevent noise and prevent the circuit board 13 from malfunctioning.

[0013] As shown in FIG.
It has a power supply terminal T1 to which 2 volts are supplied and a detection terminal T2. This detection terminal T2 also serves as the ground level of the circuit, and is grounded via the resistor RD on the MPU2 side. The circuit board 13 is provided with an oscillation circuit CO and a switching circuit SW that is turned on / off based on the oscillation state of the oscillation circuit CO.

The switching circuit SW has a power supply terminal T1.
From the detection terminal T
2 is grounded by the resistor RD (the resistance value is 680Ω in this embodiment), the power supply voltage of the switching circuit SW changes depending on the on / off state of the transistor Tr2 of the switching circuit SW. On the other hand, in the oscillation circuit CO, a resistor R1 (in this embodiment, a resistance value of 27 KΩ) interposed between the power supply terminal T1 and the detection terminal T2 and a Zener voltage Vz stabilized by a Zener diode D1 (this embodiment). About 5.5 volts in the example).

The oscillation circuit CO is a dual transistor Tr in which two transistors having the same characteristics are formed in the same chip.
1 and a capacitor C1 and a coil L1 interposed between one emitter of the double transistor Tr1 and the ground line, and an intermediate tap between the other emitter of the double transistor Tr1 and the intermediate tap of the coil L1. The resistor R3 and the capacitor C2 constitute a Colpitts-type high-frequency oscillation circuit. The base of the double transistor Tr1 is connected to a power supply line via a resistor R2. The oscillation frequency of the oscillation circuit CO is determined by the inductance of the coil L1 and the capacitors C1 and C1.
2 and about 300 KHz in this embodiment.
It has become.

One of the collectors of the double transistor Tr1 is not used, but the other is connected to the base terminal of the transistor Tr2 of the switching circuit SW. A capacitor C3 is connected between the base terminal of the transistor Tr2 and the ground line, and a resistor R4 is connected between the transistor Tr2 and the power supply line. A resistor R5 (220Ω in this embodiment) is connected to the emitter terminal. The collector terminal of the transistor Tr2 is connected to a power supply line. In a state where the oscillation circuit CO is oscillating, the double transistor Tr1 repeatedly turns on and off at about 300 KHz. When the double transistor Tr1 is on, its collector current flows from the base of the transistor Tr2 of the switching circuit SW and turns on. Turn on Tr2. On the other hand, the oscillation circuit CO
While the double transistor Tr1 is turned off for a short time due to the oscillation of the transistor Tr2, the base current of the transistor Tr2 is continued by discharging and charging the capacitor C3, and the transistor Tr2 is kept on.

When the pachinko ball P, which is a metal object, passes through the through hole 51 of the circuit board 13 in a state where the oscillation circuit CO is oscillating, the magnetic flux of the coil L1 passes through the pachinko ball P. An eddy current flows in the pachinko ball P, causing a current loss. The pachinko ball P is usually made of metal. However, even when the pachinko ball is made of a material other than metal and is plated on the surface, a thin film of plating or the like has a considerably large eddy current loss due to a small cross-sectional area. Since the generation of the eddy current consumes the oscillating energy of the oscillating circuit CO, the high frequency oscillation is remarkably attenuated and almost stopped.

When the pachinko ball P does not pass through the through hole 51 and does not approach the coil L1, that is, when the oscillation circuit CO is oscillating, the transistor Tr2 is in the on state. When the oscillation of the CO is almost stopped, the transistor Tr2 of the switching circuit SW
Turns off. Since the resistance of the resistor R5 is smaller than that of the resistor R1 (220 Ω: 27 KΩ in this embodiment), when the transistor Tr2 is turned on, the current flowing from the power supply terminal T1 to the Zener diode D1 via the transistor Tr2 and the resistor R5. Is larger than the current flowing through the resistor R1 (about 130 times in this embodiment). Since this current finally flows to the ground side via the resistor RD connected to the detection terminal T2, the voltage between both ends of the resistor RD, that is, the voltage of the input port PB1 of the MPU2 is changed when the transistor Tr2 is turned off. It is about 0.2 volts and about 4.9 volts in the on state. Therefore, MPU
2 monitors the state of the input port PB1 so that the pachinko ball detection device 1 can easily know the state of detecting the pachinko ball P (low level) and the state of not detecting the pachinko ball P (high level).

As described above, according to the pachinko ball detection device 1 of the present embodiment, the pachinko ball P can be reliably detected without contact. Moreover, in the pachinko ball detection device 1, since the coil L1 as a detection unit is configured by the wiring pattern 52 formed on the circuit board 13, the detection unit is integrated with the circuit board 13 and the number of components is reduced. You. Therefore, the reliability can be improved.
Further, since the number of components is reduced, the assembling workability is excellent, and in particular, there is no need to attach the coil L1 to the circuit board 13. In addition, the size of the pachinko ball detection device 1 is limited only by the size of the circuit board 13 itself, and can be made thin and compact. In the present embodiment, the case composed of the upper lid 11 and the lower box 12 is relatively thick in consideration of compatibility with others, but can be actually made thinner.

In this embodiment, a normal printed circuit board made of resin is used as the base material of the circuit board 13. Alternatively, a structure using a highly flexible film may be used. . With such a configuration, it is possible to provide a circuit board that is further reduced in thickness as a whole, and that is hardly damaged around the through hole 51.

Further, in the present embodiment, the wiring pattern 52 constituting the coil L1 is composed of a total of two turns, one for the front surface and one for the back surface.
As shown in (2), the wiring pattern 61 constituting the coil L1 on the circuit board 60 may be formed on each of the front surface and the back surface by two turns, and may be constituted by a total of four turns. Alternatively, the front surface and the back surface may each have three turns.

The embodiment of the present invention has been described above.
The present invention is not limited to such embodiments. For example, the circuit board 13 may be used without being housed in a case, and a plurality of through holes may be provided on one circuit board. The present invention can be implemented in various modes without departing from the gist of the present invention, such as a configuration for detecting when a subject has passed, a configuration for arranging a plurality of circuit boards 13 in parallel, and detecting a continuous pachinko ball P. Obviously you can get it. The present invention has been made by paying attention to the fact that the magnetic flux formed by the coil generates an eddy current in the metal object and consumes the oscillation energy of the oscillation circuit, and the metal object as the object is not a pachinko ball. For example metal, coins, parts,
It can be a logistics product. In this case, the through hole needs to have a shape corresponding to the subject.

[0023]

As described above, in the detecting device of the present invention, pachinko balls can be detected in a non-contact manner, and the number of components of the device is reduced, thereby improving reliability and workability of assembly. And the whole device can be made compact.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a pachinko ball detection device as one embodiment employing a detection device of the present invention.

FIG. 2 is a perspective view of the pachinko ball detection device in an assembled state.

FIG. 3 is a circuit diagram of the pachinko ball detection device.

FIG. 4 is a plan view showing another embodiment of a wiring pattern forming a coil.

FIG. 5 is an explanatory diagram showing a state of a conventional subject detection using an eddy current.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pachinko ball detection device 2 MPU 11 Upper cover 12 Lower box 13 Circuit board 51 Through hole 52 Wiring pattern CO oscillation circuit L1 Coil SW Switching circuit Tr1 Double transistor

Claims (2)

(57) [Claims] 1. A detection device, comprising a detection unit and a circuit board, for non-contactly detecting the proximity of a detection target made of metal or having a metal coating, wherein a test object passes through the circuit board. An oscillation circuit that forms a coil with a wiring pattern around the through hole, the coil serves as the detection unit, and an oscillation circuit that oscillates using an inductance component of the coil; And a switching circuit that is turned on / off in response to the detection signal. 2. A wiring pattern forming the coil,
Claims: It is configured to be formed on both front and back surfaces of the circuit board.
2. The detection device according to 1.