JPH01103319A - Proximity switch device - Google Patents

Abstract

PURPOSE:To easily detect the moving direction of an object by providing two detection electrode plates, arranging them in parallel and connecting differentially the two detection electrode plates. CONSTITUTION:An oscillated output of a prescribed frequency is radiated from an oscillation circuit 5 through both the oscillation electrodes 1, 2 and an oscillation electrode plate 3 and electric line of force are generated around the electrode plates. In such a case, the electric line of force around the electrode plate 1, for example, accessed earlier by a human body are changed and an induced voltage is generated between the two electrode plates 1, 2 connected differentially and the induced voltage is extracted from a detection coil 6. When the human body passes by the electrode plate 1 and moves on to the other electrode plate 2, the electric line of force around the electrode plate 2 are changed at this time and an induced voltage of opposite polarity to that of the preceding voltage is generated between the electrode plates. Thus, the detection signal of a different polarity is outputted in the order corresponding to the moving direction of the object thereby detecting the moving direction of the object easily.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is mainly used as a start switch for detecting the approach of an object such as a human body without contact and controlling the operation of an automatic opening/closing door or a security device. The present invention relates to a proximity switch device used.

<Prior art> As a proximity switch device used as a starting switch for controlling the opening/closing of such an automatic opening/closing door, a rubber mud is used, which is made by covering the entirety of two metal plates facing each other with a predetermined gap with waterproof rubber. Switches have been commonly used in the past. This rubber mud switch detects an approaching human body by contact between two metal plates when a human body is placed on it.Since it uses a contact type to detect the human body, for example, if it is stepped on by a high heel or a stubby foot. It has the drawbacks of being prone to breakdowns and damage to its waterproof function and having a short lifespan, and is not aesthetically pleasing because it is laid exposed in the vicinity of automatic opening/closing doors.

Therefore, as a proximity switch device that eliminates these drawbacks, two sensing plates made of metal plates are buried underground in the mat near the automatic opening/closing door, and these sensing plates are used as part of the oscillation circuit. When the human body approaches the buried sensing plate,
The oscillation frequency of the oscillation circuit changes due to stray capacitance and resistance loss between the human body and the sensing plate, and the output level changes according to the change in Q. This change is taken out to the outside and operates the switch section. , A non-contact detection method has been devised to control the opening and closing of an automatic opening/closing door.

<Problems to be Solved by the Invention> However, even in the non-contact detection type proximity switch device, due to the fact that two sensing plates made of metal plates are used as part of the oscillation circuit, There are various problems as follows. In other words, since the oscillating part uses the sensing plate as part of the oscillation circuit, it is preferable to install the oscillating part near the sensing plate.If the oscillating part is buried underground together with the sensing plate, it is preferable to install the oscillating part near the sensing plate. Due to impedance, it is generally used by placing it inside a sensing plate within the same electric field.

The reason for doing this is that when the oscillator is separated from the sensing plate,
This is because due to impedance, another electric field is generated in the feeder line connecting the two, making it impossible to use the sensing plate as part of the oscillation circuit.

However, using a structure in which the oscillating part is housed in the sensing plate has a great practical inconvenience. That is, in the case of inspection and repair due to a malfunction in the oscillating section, it is necessary to remove the entire sensing plate, and in particular, removing the floor such as tiles is a large-scale construction work. Additionally, if a maintenance hole is provided in advance, the above problem can be resolved, but providing such a hole in front of an automatically opening/closing door poses problems in terms of aesthetic appearance and smooth passage. .

Furthermore, in the opening/closing control of automatic opening/closing doors, cooling,
To prevent cold or warm air from escaping outside during heating,
It is preferable to open the door quickly when the human body approaches the door, and close it as quickly as possible when the human body moves away from the door. However, with conventional devices, it is not possible to determine the direction of movement of a human body relative to the door, so the door remains open for a relatively long period of time in order to ensure safety when a human body passes through the door.

<Purpose of the Invention> The present invention has been made in view of the above-mentioned conventional technical problems, and it is possible to install a detection section consisting of a buried electrode plate and a control section consisting of an oscillation section, a detection section, etc. at an arbitrary distance. To provide a proximity switch device having a configuration that does not generate unnecessary radio waves in a signal transmission line such as a cable connecting the two and can also determine the direction of movement of a human body even when This is the purpose.

Means for Solving the Problems> The present invention constitutes technical means for solving the problems as follows. That is, an oscillation circuit composed of a crystal resonator or the like and outputting a predetermined frequency signal, and a detection electrode plate and an oscillation electrode plate that are buried close to each other and function as an antenna for outputting the oscillation signal of the oscillation circuit. At least two of the detection electrode plates are provided and arranged in parallel, and the two detection electrode plates are differentially connected to each other, and the difference due to the induced voltage generated in each of the two detection electrode plates is It is characterized by a configuration that includes a detection circuit that detects a change of a certain level or higher in a dynamic signal.

Effect> With the above configuration, the oscillation signal of the oscillation circuit is radiated using at least two detection electrode plates and the oscillation electrode plate as antennas, so lines of electric force are generated around each electrode plate. do. Here, it is assumed that two detection mold plates are arranged along the moving direction of the object to be detected. When a human body approaches the detection area where each electrode plate is embedded, the dielectric constant around one of the detection electrode plates closer to the human body changes, and the lines of electric force change accordingly.

Therefore, an induced voltage is generated between the two differentially connected detection electrode plates, and when the absolute value of this voltage becomes greater than the set level of the detection circuit, a signal is sent from the detection circuit to activate the switch section. is output. Next, when the human body passes through one sensing electrode plate and approaches the other sensing electrode plate,
Contrary to the above, the lines of electric force around the other detection electrode plate change and an induced voltage of opposite polarity is generated, and the signal output of the detection circuit continues until the absolute value of this voltage becomes smaller than the set level of the detection circuit. is retained.

In this proximity switch device, unlike existing devices, each electrode plate is not a part of the oscillation circuit component, and each electrode plate acts simply as an electrode that outputs an oscillation signal, and the oscillation frequency and output level are Because it is determined by the oscillation circuit itself, even if each electrode plate and the oscillation circuit, detection circuit, etc. are separated and installed at an arbitrary location, another electric field will be generated in the signal transmission line such as a cable that connects them. No, there is no inconvenience.

Furthermore, when two detection electrode plates are arranged along the direction of movement of the human body as described above, two types of induced voltages with different polarities are generated in the order corresponding to the direction of movement of the human body.
In addition to detecting the approach of a human body based on the magnitude of the absolute value of this induced voltage, it is also possible to detect the moving direction of the human body by determining the order in which the two polarity induced voltages are generated.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

In FIG. 1 showing the block configuration of the present invention, the detection area, for example, when used as a start switch for an automatic opening/closing door, the sensing part buried in the vicinity of the automatic closing door is made of a high-quality material such as urethane foam. Two sensing electrode plates 1 juxtaposed with a spacer member 4 having a dielectric constant interposed therebetween
．． 2 and a single earth-side oscillation electrode plate 3 are joined together with a spacer member 4 similar to that described above interposed therebetween.

As each of the electrode plates 1 to 3, in addition to a simple metal plate, those having a wire-like shape, a grid-like shape, and a shelf-like shape can be used.

The oscillation circuit 5 is composed of components such as a crystal resonator, and outputs a constant oscillation frequency signal, and outputs the oscillation signal through each detection electrode plate 1.2 and the ground side oscillation electrode plate 3. . That is, each electrode plate 1 to 3 has an oscillation circuit 5
It functions not as one of the constituent members but as a mere antenna of the oscillation circuit 5, and each detection electrode plate 1.2 is also used as an oscillation electrode plate.

The detection coil 6 is a part of the component of the amplifier circuit 7 in the subsequent stage, and both ends of the primary coil section are connected to each detection electrode plate 1.2, and the primary coil section The center tap of the oscillator is connected to the oscillation circuit, and the secondary coil portion is connected to the amplifier circuit 7. That is, both the detection electrode plates 1 and 2 are differentially connected via the detection coil 6,
The amplifier circuit 7 amplifies the differential signal caused by the induced voltage generated in each of the sensing electrode plates 1 and 2.

The detection circuit 8 compares the output of the amplifier circuit 7 with a predetermined set level and outputs a signal when the output exceeds the set level. The output circuit 9 includes a switch section for controlling the opening and closing of an automatic opening/closing door, and a relay coil of the switch section is energized by the output of the detection circuit 8.

Next, to explain the operation of the above embodiment, the oscillation output of a constant frequency from the oscillation circuit 5 is transmitted to both the detection electrode plates 1 and 2.
By being radiated through the oscillation electrode plate 3, lines of electric force are generated around each of the electrode plates 1 to 3. When a human body approaches the detection area where each of the electrode plates 1 to 3 is buried while moving in the direction of the arrow shown in the figure,
The lines of electric force between the detection electrode plate 1.2 and the oscillation electrode plate 3 do not change because the dielectric constant hardly changes due to the presence of the high-permittivity spacer member 4. The electric lines of force in the space above the sensing electrode plate 1.2 change in response to the change in dielectric constant as the human body approaches. In this case, the lines of electric force around one of the sensing electrode plates 1 to which the human body approaches first changes, and an induced voltage is generated between the two differentially connected sensing electrode plates 1 and 2. At the same time, this induced voltage is amplified and taken out from the secondary coil section, and when the absolute value of this output voltage becomes larger than the set level of the detection circuit 8, a signal is output from the detection circuit 8 and the relay coil of the output circuit is output. is energized.

Then, when the human body passes through one sensing electrode plate and moves onto the other sensing electrode plate 2, the lines of electric force around the other sensing electrode plate 2 change, and each sensing electrode Board 1
．． An induced voltage with a polarity opposite to that described above is generated between the two, and the signal output of the detection circuit is held until the absolute value of this voltage becomes smaller than the set level of the detection circuit 8, and the signal is output from the detection circuit 8. During this period, the automatic opening/closing door is opened via the output circuit 9.

This proximity switch device differs from existing devices that use an electrode plate as one of the components of the oscillation circuit to detect deviations in oscillation frequency and changes in intensity due to the proximity of a human body. Since the electrode plate 1.2 and the oscillation electrode plate 3 only function as an antenna for the oscillation circuit 5, the control unit consists of a detection section consisting of each electrode plate 1 to 3, and other oscillation circuits 5, detection circuits 8, etc. The length of the signal transmission line connecting the parts can be set arbitrarily. Therefore,
The control section can be installed at any location, and the wiring location of the signal transmission line can also be selected at will, depending on the situation at the site where the proximity switch device is installed. Moreover, since the two detection electrode plates 1 and 2, which also serve as oscillation electrode plates, are differentially connected to detect this differential signal, cables etc. between the electrode plates 1 and 2 and the oscillation circuit 5, etc. The influence of the signal transmission line and the influence of disturbance factors such as rain, humidity (amount of water vapor in the air), and changes in the surrounding environment are canceled out, resulting in extremely high reliability.

FIG. 2 shows another embodiment of the present invention, in which the same parts as in FIG. 1 are given the same reference numerals. In a configuration in which a polarity discrimination circuit 10 is connected to the amplifier circuit 7 and AND gates 11 and 12 are provided for calculating the logical product of the two types of discrimination signals of the polarity discrimination circuit 10 and the detection signal of the detection circuit 8, the first
It is different from the one in the illustration.

As explained in Fig. 1, by arranging the two detection electrode plates 1.2 along the direction of movement of the human body, signals of different polarities are transmitted in the order corresponding to the direction of movement when the human body passes. Therefore, the polarity determining circuit 10 determines the moving direction of the human body based on the order in which these signals of different polarity are generated. Therefore,
It can determine whether the human body is moving toward or away from the automatically opening/closing door.
The door can be controlled to open quickly when approaching the door, and close quickly when moving away from the door.

FIG. 3 shows still another embodiment of the present invention, in which the same components as in FIGS. , the first amplifier circuit 7 and the first detection circuit 8, a second detection coil 13. Second amplifier circuit 14 and second detection circuit 15
, and an OR gate 16 that takes the logical sum of the detection signals of both detection circuits 8.15. The primary side coil part of the second sensing coil 13 is the first sensing coil 6
is inserted and connected between the intermediate tap of the oscillator circuit 5 and the first
The differential signal of the detection coil 6 becomes almost zero, but the sum signal of each current due to the voltage induced by both detection electrode plates 1 and 2 flows through the second detection coil 13, so this can be detected. By using the detection signal as a detection signal, a decrease in detection sensitivity in the above-mentioned state is prevented.

It should be noted that the present invention is not limited to the above description and illustrated examples, and may include various modified embodiments without departing from the scope of the claims. For example, in the above embodiment, the case where the switch is used as a starting switch for an automatically opening/closing door has been described, but it can also be used as a switch for detecting a human body or a moving object in crime prevention or safety equipment. Further, the number of detection electrode plates 1.2 is not limited to two, but may be an even number for differential connection. The spacer member 4 interposed between the electrode plates 1 to 3 is not limited to a foamed urethane-based material, but may also be made of another high dielectric constant material. It may be a space, and furthermore, the oscillation electrode plate 3 and the detection electrode plate 1.2 do not necessarily need to be parallel to each other.

<Effects of the Invention> Since the present invention is configured and operates as described above, according to the proximity switch device of the present invention, at least two detection electrode plates and oscillation electrode plates are components of the oscillation circuit. Since it functions as a mere antenna rather than a part of the antenna, it is not affected by the length of the signal transmission line that connects the detection section consisting of each electrode plate and the control section consisting of an oscillation circuit, detection circuit, etc. Wiring of the signal transmission line can be selected arbitrarily, and inspection and repair can be easily carried out.

Moreover, since the detection electrode plates are differentially connected to detect this differential signal, the influence of signal transmission lines such as cables between the electrode plates 1.2 and the oscillation circuit 5, rain, humidity (air The effects of disturbance factors such as the amount of water vapor) or changes in the surrounding environment are canceled out, resulting in extremely high reliability.

Furthermore, since differential signals are detected, if each detection electrode plate is arranged along the moving direction of the object to be detected, detection signals of different polarities will be output in the order corresponding to the moving direction of the object. This has the advantage that the moving direction of an object can be easily detected, and in particular, the automatic opening/closing door can be effectively controlled.

Furthermore, since the oscillation frequency and output level are determined only by the oscillation circuit, stable operation is achieved without malfunctions. Furthermore, the detection sensitivity can be adjusted by adjusting only the detection sensitivity of the detection circuit itself or the sensitivity of the detection side, such as the amplification degree of the amplifier circuit in the preceding stage, without considering oscillation tuning. becomes easier.

[Brief explanation of the drawing]

1 to 3 are block diagrams of different embodiments of the present invention. 1.2...Detection electrode plate 3...Oscillation electrode plate 5...Oscillation circuit 8...Detection circuit 10...Polarity discrimination circuit 15...Second detection circuit

Claims (3)

[Claims] (1) An oscillation circuit that is composed of a crystal oscillator and the like and outputs a predetermined frequency signal, and a detection electrode plate and an oscillation electrode plate that are buried close to each other and function as an antenna that outputs the oscillation signal of the oscillation circuit. At least two detection electrode plates are provided and these are juxtaposed, and these two detection electrode plates are provided.
The present invention is characterized in that two detection electrode plates are differentially connected to each other, and a detection circuit is provided for detecting a change of a differential signal of a certain level or more due to an induced voltage generated in each of the two detection electrode plates. Proximity switch device. (2) The two detection electrode plates are arranged along the moving direction of the object to be detected, and a polarity discrimination circuit is provided to discriminate the polarity of the differential signal of the two detection electrode plates. A proximity switch device according to claim 1, characterized in that: (3) The two detection electrode plates are arranged along the moving direction of the object to be detected, and a second detection electrode plate is arranged to detect a change of a differential signal of the two detection electrode plates above a certain level. 1
a second detection circuit for detecting a change of a sum signal of the two detection electric plates at a certain level or more, and an OR gate for calculating the logical sum of the respective outputs of the two detection circuits. A proximity switch device according to claim 1, characterized in that: