JP4013106B2 - Proximity switch - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a proximity switch effective for detecting rolling of a pachinko ball, for example, in a pachinko gaming machine, and more specifically, when the radio wave is irradiated to the proximity switch for the purpose of fraud, The present invention relates to a proximity switch having a function capable of detecting and preventing abnormal operation of the proximity switch.
[0002]
[Prior art]
Conventionally, when a strong radio wave that would cause a malfunction to a proximity switch used in a pachinko game machine has been irradiated, a radio wave detection circuit is provided to detect this radio wave, and the proximity switch malfunctions at the output of the radio wave detection circuit As a technique for preventing this, there is a technique disclosed in Japanese Patent No. 2924070.
[0003]
In this conventional technology, the radio wave resistance performance of the basic circuit constituting the proximity switch and the radio wave resistance performance of the radio wave detection circuit are completely independent. It is necessary to set the electric field strength detection level of the detection circuit.
[0004]
However, the above-mentioned characteristic variation factors include multiple variations with different properties, such as variations due to environmental conditions, variations in the characteristics of elements in the semiconductor integrated circuit, and variations in the production lot of the semiconductor integrated circuit. In consideration of this, the range (or width) of the characteristic variation becomes wider, and when setting the electric field strength detection level of the above-described radio wave detection circuit, the above-mentioned basic circuit resistance is provided so that the range of the characteristic variation can be covered. It must be set at a level lower than necessary than the field strength limit level.
[0005]
However, with this setting, there is a possibility that the radio wave detection circuit will operate due to, for example, the use state of commercial communication equipment such as mobile phones owned by the player, equipment noise in the game hall, etc. Therefore, it is impossible to deny the possibility of commercializing communication equipment in a completely different frequency band from the current situation, or communication equipment with a different method from the conventional one, and it is necessary to finish the characteristics so that they are not affected as much as possible by anti-radiation performance. There is.
[0006]
[Problems to be solved by the invention]
In the present invention, in setting the electric field strength detection level of the radio wave detection circuit, the variation in the characteristics of the proximity switch is considered as little as possible, and is set as close as possible to the electric field strength limit level that functions as the proximity switch. An object of the present invention is to provide a proximity switch that can be used.
[0007]
[Means for Solving the Problems]
In the present invention, a basic circuit that outputs an object detection signal when a change of a predetermined amount is detected by comparing a change in output of an oscillation circuit unit accompanying the proximity of an object with a comparison circuit unit is constituted by a semiconductor integrated circuit and a passive component. a proximity switch that, wave sensing and disables the output of the object detection signal by the basic circuit upon detection of a radio wave having a predetermined intensity coming from the outside, using a radio wave sensing element for the operation of the radio waves detected in the circuit A circuit is provided, and the radio wave detection element is built in the semiconductor integrated circuit. Among the elements used in the basic circuit, an element having the lowest radio wave resistance is compared with the radio wave detection element. thing, and the wave detection device are denoted by the difference in electromagnetic interference characteristics in the same process configuration as the comparison element is a proximity switch which is formed by the electromagnetic interference characteristic predetermined value lower than the comparison element And features.
[0008]
According to the present invention, since the basic circuit of the proximity switch and the radio wave detection circuit are configured by a semiconductor integrated circuit in the same chip, the electric field intensity limit level at which the basic circuit itself operates abnormally by radio waves, and the radio wave detection Changes in characteristics such as the influence of environmental conditions, variations in device characteristics, variations in production lots of semiconductor integrated circuits, etc., which have been a factor of characteristic variation, are not independent of each other and are equivalent. Thus, the relative relationship between the electric field intensity limit level of the basic circuit and the radio wave detection level of the radio wave detection circuit is not lost.
[0009]
Therefore, it is possible to easily set the operation level of the radio wave detection circuit by design.
[0010]
Moreover, since the element with the lowest anti-radiation characteristics in the basic circuit of the proximity switch can be grasped during the design, the overall characteristics of the basic circuit can be determined by specifying this as a comparison target. It is easier to set the operation level of the radio wave detection circuit by considering only the characteristics of a specific element rather than considering it.
[0011]
Furthermore, the element having the lowest anti-radiation characteristics in the basic circuit is set as an element to be compared with the above-described radio detection element, and the radio detection element is different from the anti-radiation characteristics in the same process configuration as the above-described comparison target element. Since the conditions other than the difference are the same when formed with a mark , a highly accurate setting is possible.
[0012]
As the difference in the above-described process configuration, for example, the radio wave detection element and the comparison target element are formed in an NPN type, and the P + type diffusion layer of the base electrode of both the elements and the N + of the emitter electrode are formed. The difference in layer thickness with the mold diffusion layer can be the difference in the process configuration.
[0013]
Further, the radio wave detection element and the comparison target element can be formed in an NPN type, and the difference in the area of the N + type diffusion layer of the emitter electrode of the both elements can be a difference in the process configuration. .
[0014]
Further, the radio wave detection element and the comparison target element are formed in an NPN type, and the difference in impurity concentration of the P + type diffusion layer forming the base electrode of the both elements is defined as the difference in the process configuration. be able to.
[0015]
[Operation and effect of the invention]
According to the present invention, the radio wave intensity detection level of the radio wave detection circuit can be set as close as possible to the electric field intensity limit level that functions as a proximity switch, and the unauthorized radio wave irradiated to the proximity switch for the purpose of fraud Therefore, it is possible to detect this reliably to prevent abnormal operation of the proximity switch, and make it a characteristic that is not affected as much as possible by radio waves from normal communication equipment or noise from equipment. be able to.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings.
[0017]
The drawing shows a proximity switch. In FIG. 1, the proximity switch 10 includes a substantially block-shaped case body 11 and a transparent cover member 14 attached by engaging a locking piece 13 with a protrusion 12 of the case body 11. A circuit portion 15 surrounded by the cover member 14, a through hole 17 that allows a pachinko ball (metal ball) 16 to pass through, a bobbin case 18 provided at the inner edge of the through hole 17, A resonance coil 19 wound around a bobbin case 18 is provided.
[0018]
In addition, since the above-mentioned cover member 14 is transparent, the internal circuit part 15 can be visually confirmed from the outside.
[0019]
FIG. 2 shows a configuration of the circuit unit 15 of the proximity switch 10. The basic circuit 20 of the proximity switch 10 uses the above-described resonance coil 19, for example, an oscillation circuit 21 formed in a Hartley type, and detects an oscillation signal. A detection circuit 22 that performs the detection, an integration circuit 23 that integrates the detected signal, a comparison circuit 24 that compares the integration signal with a reference signal set to determine the pachinko ball 16 and outputs a comparison result, and a comparison result When a pachinko ball is detected based on the output, the output circuit 25 outputs a detection signal and the power supply circuit 26 that supplies power to each circuit. These circuits include an NPN transistor, and include one chip. It is formed of a semiconductor integrated circuit and passive components.
[0020]
The radio wave detection circuit 30 is a circuit that turns a detection signal output from the output circuit 25 of the basic circuit 20 into a non-detection signal that cannot be output when a radio wave having a predetermined intensity that causes malfunction due to arrival from the outside is detected. For example, when the pachinko ball 16 is not detected by the output circuit 25 described above, “H” level is output, and when the pachinko ball 16 is detected, “L” level is output. Then, when the radio wave detection circuit 30 detects a radio wave of a predetermined intensity, the “H” level is output to the output circuit 25 during the detection and the pachinko ball 16 is not detected forcibly. Set to output state.
[0021]
In this state, even if the above-described unauthorized radio wave causes the basic circuit 20 to malfunction and a signal corresponding to the “L” level at which the pachinko ball 16 is detected is output from the comparison circuit 24, the “ Since the output circuit 25 is forced to be in the non-detection output state in which the pachinko ball 16 is not detected at the H ”level, unauthorized operation can be prevented.
[0022]
The radio wave detection circuit 30 includes a radio wave detection transistor 31 formed of an NPN transistor, resistors R1 to R5, and a comparator 32. These circuits are one chip of a semiconductor integrated circuit in which the basic circuit 20 is formed. Built in.
[0023]
The resistors R1 and R2 described above are base resistors for determining the emitter voltage V1 of the radio wave detection transistor 31, resistors R3 are bias resistors, and resistors R4 and R5 are voltage dividing resistors for determining the reference voltage V2 of the comparator 32. The radio wave detection transistor 31 operates by receiving radio waves.
[0024]
At the time of designing the basic circuit 20 described above, the transistor having the lowest anti-radiation characteristics in the circuit 20 can be grasped. By specifying (setting) this as a comparison target, the entire basic circuit 20 can be identified. It is easier to set the operation level for the radio wave detection of the radio wave detection circuit 30 by considering only the radio wave resistance characteristic of the transistor specified as the comparison target, rather than considering the radio wave resistance characteristic.
[0025]
Further, since the basic circuit 20 and the radio wave detection circuit 30 are formed of a semiconductor integrated circuit in the same chip, the electric field strength limit level at which the basic circuit 20 itself abnormally operates due to radio waves, and the radio wave detection of the radio wave detection circuit 30 are detected. Levels are relative to each other, and changes in characteristics such as the influence of environmental conditions, variations in device characteristics, and variations in production lots of semiconductor integrated circuits, which have been factors of characteristic variations in the past, are not independent, but become equivalent characteristics changes. The relative relationship between the electric field intensity limit level of the basic circuit 20 and the radio wave detection level of the radio wave detection circuit 30 does not collapse.
[0026]
Therefore, the setting of the operation level of the radio wave detection circuit 30 can be easily performed by design.
[0027]
FIG. 3 shows an explanation of the case where the operation level for the radio wave detection of the above-described radio wave detection transistor 31 is set. The transistor 33 shown in FIG. 3 is an NPN transistor, and as described above, in the basic circuit 20. The transistor having the lowest radio wave resistance is set as a comparison target, and the operation level of the radio wave detection transistor 31, that is, the radio wave detection level is set.
[0028]
The radio wave resistance characteristics of the radio wave detection transistor 31 described above are formed to be a predetermined value lower than the radio wave resistance characteristics of the transistor 33 for comparison described above, and the predetermined value is set to a value as close as possible. is doing. In addition, this setting is made by adding a difference in the configuration of the manufacturing process when forming both transistors 31 and 33 as will be described later.
[0029]
FIG. 4 shows both transistors 31 (a) and 33 (b) and a comparator 32 when radio waves act on the radio wave detection transistor 31 and the comparison target transistor 33 set with the operation level of radio wave detection as described above. (C) shows the output state.
[0030]
The reference voltage V2 of the comparator 32 shown in FIG. 3 is set to a value V2 that is close to the limit at which the comparison target transistor 33 does not malfunction due to the influence of radio waves, and the emitter voltage V1 of the radio detection transistor 31 is It is set to a slightly higher V1.
[0031]
When a radio wave arrives from the outside, both transistors 31 and 33 are affected, but the amount of influence is large in the radio wave detection transistor 31 and small in the comparison target transistor 33. The radio wave detection transistor 31 operates when a radio wave such as a weak radio wave, a strong radio wave, or an intense radio wave arrives. When the radio wave is a strong radio wave or a strong radio wave, the emitter voltage V1 drops below the reference voltage V2. As a result, the output Vx from the comparator 32 is output at the “L” level, and this “L” level output is output to the output circuit 25 shown in FIG. 2 as a radio wave detection signal.
[0032]
It is assumed that the output circuit 25 is set to output “H” level when the pachinko ball 16 is not detected, and to output “L” level when the pachinko ball 16 is detected. The radio wave detection signal output from the above-described comparator 32 is inverted to “H” level, and “H” level is output to the output circuit 25 while the radio wave causing the malfunction is detected, forcibly causing the pachinko ball. 16 is set to a non-detection output state where no detection is performed.
[0033]
FIG. 5 shows an example in which the operation level of the radio wave detection transistor 31 is set with a difference in the configuration of the manufacturing process when the transistors 31 and 33 are formed.
[0034]
FIG. 5A shows the above-described comparison transistor 33, and FIG. 5B shows the above-described radio wave detection transistor 31. Both the transistors 31 and 33 are built in one chip of the semiconductor integrated circuit as described above. Is done.
[0035]
Both transistors 31 and 33 are NPN transistors and have the same structure. That is, the P-type substrate 42 is formed on the lower surface of the N− type semiconductor layer 41 and the periphery is surrounded by the isolation P + type buried layer 43 to form element regions of the respective transistors 31 and 33.
[0036]
On the upper surface of each element region described above, an N + type extraction layer 45 connected with a collector electrode 44, a P + type diffusion layer 47 connected with a base electrode 46, and an N + type connected with an emitter electrode 48 on the upper surface of the P + type diffusion layer 47. A mold diffusion layer 49 is formed, and an insulating layer 50 is formed on these upper surfaces with the electrodes 44, 46, 48 exposed. In the figure, reference numeral 51 denotes an N + type buried layer.
[0037]
In the above-described layer thickness difference a1 and a2 between the diffusion layer 47 of the base electrode 46 and the diffusion layer 49 of the emitter electrode 48, the difference in layer thickness a1 of the transistor 33 for comparison is common. If the configuration is a simple manufacturing process, the radio wave detection transistor 31 is formed so that the diffusion layer 47 of the base electrode 46 is thin and has a thin layer thickness difference a2, both of which are a1> a2
The difference is provided.
[0038]
FIG. 6 is a characteristic diagram showing the relationship between the above-described layer thickness difference a1 and a2 and the electric field intensity level at which the NPN transistor malfunctions. As illustrated, the layer thickness difference a2 is small. When it is (thin), the electric field strength level is low, and when it is large (thick) like the layer thickness difference a1, the electric field strength level is high. Therefore, the layer thickness difference a2 of the radio wave detection transistor 31 is used for comparison. The field intensity level of the radio wave detection transistor 31 can be made lower than that of the comparison target transistor 33 by reducing the layer thickness difference a1 of the transistor 33 by an amount (set amount) corresponding to the set field intensity level. As a result, the radio wave detection transistor 31 operates first with respect to a radio wave that causes a malfunction from the outside, and the malfunction of the basic circuit 20 can be prevented.
[0039]
FIG. 7 shows another example for forming the layer thickness difference a2 of the above-described radio wave detection transistor 31. The depth of the diffusion layer 47 of the base electrode 46 is set to a normally formed depth, and the emitter is formed. The depth of the diffusion layer 49 of the electrode 48 is increased by a predetermined amount to form a thin layer thickness difference a2. Even if it forms in this way, the function similar to the case shown in FIG.
[0040]
FIG. 8 shows another example in which the operation level setting of the radio wave detection transistor 31 is formed by adding a difference in the configuration of the manufacturing process when the transistors 31 and 33 are formed.
[0041]
In this example, the operation level of the radio wave detection transistor 31 is set by the difference in the area in plan view of the N + type diffusion layer 49 to which the emitter electrodes 48 of the transistors 31 and 33 are connected.
[0042]
FIG. 8A shows the above-described comparison transistor 33, and FIG. 8B shows the above-described radio wave detection transistor 31, and the configuration of the transistor is the same as that shown in FIG. Elements are denoted by the same reference numerals, and detailed description thereof is omitted.
[0043]
Both transistors 31 and 33 shown in the figure are formed on the upper surface of each element region, an N + type extraction layer 45 connected to the collector electrode 44, a P + type diffusion layer 47 connected to the base electrode 46, and an upper surface of the P + type diffusion layer 47. Shows an N + type diffusion layer 49 to which an emitter electrode 48 is connected.
[0044]
The area b1 × b2 of the N + type diffusion layer 49 of the emitter electrode 48 of the transistor for comparison 33 described above is the smallest area in the basic circuit 20, and it has been found at the design stage that this is the minimum area. Yes.
[0045]
On the other hand, the area b3 × b4 of the N + type diffusion layer 49 of the emitter electrode 48 of the radio wave detection transistor 31 is formed to be smaller than the area of the transistor for comparison 33 described above, and both are areas.
b1, b2> b3, b4
The difference is provided.
[0046]
FIG. 9 is a characteristic diagram showing the relationship between the area b1, b2, b3, b4 of the above-mentioned emitter electrode diffusion layer and the electric field intensity level at which the NPN transistor malfunctions. As shown in FIG. When the area of the diffusion layer 49 is small, the electric field strength level is low, and when the area is large, the electric field strength level is high. Therefore, the areas b3 and b42 of the radio wave detection transistor 31 are set to the area of the comparison target transistor 33. By reducing the amount (set amount) corresponding to the set electric field strength level from b1 and b2, the electric field strength level of the radio wave detection transistor 31 can be made lower than that of the comparison target transistor 33. The radio wave detection transistor 31 operates first with respect to the radio wave that causes the malfunction of the basic circuit 20, thereby preventing the malfunction of the basic circuit 20. .
[0047]
FIG. 10 shows still another example of the case where the operation level setting of the radio wave detection transistor 31 is formed by adding a difference in the configuration of the manufacturing process when forming both the transistors 31 and 33.
[0048]
In this example, the P + diffusion layer 47 connected to the base electrode 46 of the transistor 31 has a concentration difference that is higher (P ++ type) than the base electrode 46 of the comparison target transistor 31 (not shown). The operation level of the transistor 31 is set.
[0049]
Since the radio wave detection transistor 31 in FIG. 10 is the same as that shown in FIG. 5B, the same reference numerals are given to components having the same functions, and detailed description thereof is omitted.
[0050]
FIG. 11 is a characteristic diagram showing the relationship between the impurity concentration of the P + type diffusion layer 47 connected to the base electrode 46 described above and the electric field intensity level at which the NPN transistor operates abnormally. As the impurity concentration of the P + -type diffusion layer 47 connected to 46 increases (P ++ type), the electric field strength level decreases, so that the impurity concentration corresponding to the set electric field strength level (set amount) increases (P ++ type). By doing so, the electric field intensity level of the radio wave detection transistor 31 can be made lower than that of the comparison target transistor 33. As a result, the radio wave detection transistor 31 operates first with respect to the radio wave that causes an external malfunction, A malfunction of the basic circuit 20 can be prevented.
[0051]
In the correspondence between the configuration of the present invention and the above-described embodiment,
The oscillation circuit unit of the present invention corresponds to the oscillation circuit 21 including the resonance coil of the embodiment.
The comparison circuit unit corresponds to the comparison circuit 24,
The radio wave detection element corresponds to the radio wave detection transistor 31,
The element for comparison corresponds to the transistor for comparison,
The present invention is not limited to the configuration of the above-described embodiment, and many embodiments can be obtained.
[Brief description of the drawings]
FIG. 1 is an external perspective view of a proximity switch.
FIG. 2 is a block circuit diagram of a proximity switch.
FIG. 3 is an explanatory circuit diagram for setting an operation level of a radio wave detection transistor.
FIG. 4 is an explanatory diagram showing an output waveform.
FIG. 5 is a cross-sectional view of a transistor for explaining a difference in a diffusion layer.
FIG. 6 is a characteristic diagram showing the relationship between the electric field intensity level and the difference between the diffusion layers.
FIG. 7 is a cross-sectional view of a transistor showing another example of difference.
FIG. 8 is a cross-sectional view of a transistor for explaining a difference in area of a diffusion layer.
FIG. 9 is a characteristic diagram showing the relationship between the electric field intensity level and the difference in the area of the diffusion layer.
10 is a cross-sectional view of a transistor for explaining a difference in impurities in a diffusion layer. FIG. 11 is a characteristic diagram showing a relationship between a field strength level and a difference in impurity concentration in the diffusion layer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Proximity switch 20 ... Basic circuit 30 ... Radio wave detection circuit 31 ... Radio wave detection transistor 33 ... Transistor for comparison 46 ... Base electrode 47 ... P + type diffusion layer 48 ... Emitter electrode 49 ... N + type diffusion layer

Claims (4)

A proximity switch consisting of a semiconductor integrated circuit and a passive component is used as a basic circuit that outputs an object detection signal when a change of a predetermined amount is detected by comparing the output change of the oscillation circuit part due to the proximity of an object with a comparison circuit part. There,
When detecting a radio wave of a predetermined intensity coming from the outside, the output of the object detection signal by the basic circuit is disabled , and a radio wave detection circuit using a radio wave detection element that performs a radio wave detection operation is provided in the circuit,
The radio wave detection element is built in the semiconductor integrated circuit,
Among the elements used in the basic circuit, an element having the lowest anti-radiation characteristics is set as an element to be compared with the above-described radio wave detection element,
A proximity switch in which the radio wave detection element is formed by adding a difference to the anti-radiation characteristics with the same process configuration as the comparison target element and lowering the anti-radiation characteristics by a predetermined value compared to the comparison target element . The radio wave detection element and the comparison target element are formed in an NPN type,
And the P + -type diffusion layer of the base electrode of the both elements, the proximity switch according to claim 1 the difference in the layer thickness of the N + -type diffusion layer of the emitter electrode, which without the difference of the process configuration. The radio wave detection element and the comparison target element are formed in an NPN type,
The difference between the area of the N + -type diffusion layer of the emitter electrodes of the both elements, the proximity switch according to claim 1 without the difference of the process configuration. The radio wave detection element and the comparison target element are formed in an NPN type,
The difference in the impurity concentration of the P + -type diffusion layer forming the base electrode of the both elements, the proximity switch according to claim 1 without the difference of the process configuration.

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