JPS59214713A - Electrostatic capacity type displacement detector - Google Patents

Abstract

PURPOSE:To make a detector compact and to detect the displacement of a moving body highly accurately, by providing an auxiliary electrode, which cancels one of transmitted noise and roundabout noise, at the back surface of a fixed plate, and canceling the noise mixed into a receiving electrode from a wiring pattern. CONSTITUTION:Transmitted noise, which is mixed into an receiving electrode 14 from a pattern electric path 22a that is most closely located to the receiving electrode 14, is canceled by a correcting signal from an auxiliary electrode 26. The signal is induced based on a signal, whose phase is reverse with respect to the transmitted noise, by a transmitting electrode 12-2. Approximately the total amount of the transmitted noise mixed into the receiving electrode 14 from a wiring pattern 22 can be canceled. An AC voltage having the phase of 180 degrees, is applied to a transmitting electrode 12-3. An auxiliary electrode, which is conducted to the receiving electrode 14, is provided at the back surface of the electrode 12-3. Noise, which is mixed from a pattern electric path 22b that conducts an AC voltage of 0 degree, can be effectively canceled by a correcting signal induced by the transmitting electrode 12-3. In this way, approximately the total amount of the roundabout noises, which is mixed along the surface of a fixed plate 10 from the wiring pattern 10, can be effectively canceled.

Description

[Detailed Description of the Invention] Field of Application of Tsuya Chichi The present invention relates to an electrostatic implant type displacement detector, in particular, a device that detects the moving displacement of a moving body using a movable IE pole linked to the movable body and a fixed electrode fixed to the main body. The present invention relates to a capacitive displacement detector that detects based on a change in capacitance between two electrodes.

BACKGROUND ART Displacement detectors that electrically convert the mechanical displacement of a measuring point or the displacement of a moving base to detect the amount of displacement have been well known, and this type of device is usually movable to the main body of the device. and an encoder that detects the amount of movement of the moving body and converts it into an electrical signal Noculus, and counts electrical signal pulses output by the encoder with a counting circuit,
The counted value is digitally displayed on the digital display.

Conventionally, photoelectric encoders, contact encoders, electrostatic encoders, and the like are well known as encoders used in this type of device.

A photoelectric encoder includes slits provided at equal intervals on the surface of a scale or a rotating disk, and a light emitter and a light receiver that form an optical path through the slits of the scale or rotating disk. The scale or disk is moved or rotated in accordance with the amount of displacement to turn on and off the optical path formed between the light emitters, thereby detecting the amount of displacement of the moving body.

However, this photoelectric encoder has disadvantages in that the power consumption of the light emitter is large, the number of times the battery used has to be replaced increases, and if a large capacity battery is used, the entire device becomes large. Furthermore, in order to increase the accuracy of 611, it is necessary to provide slits at intervals of several microns on a scale or rotating disk, which is difficult to manufacture and also tends to cause miscounts due to clearance changes during operation. was there.

In addition, contact type encoders use slits, brushes, etc. to detect the displacement of the moving body, so these slits, brushes, etc.
There were problems in that the brushes were severely worn out and noise was easily mixed into the measurement signal.

On the other hand, electrostatic encoders do not consume as much power as photoelectric encoders, and they do not have the problems of brush and slit wear and noise contamination that contact encoders do, so they have been used in recent years to detect moving objects. Widely used in equipment.

Conventional technology In conventional encoders of the type used in such displacement detectors, a plurality of pairs of electrode plates are arranged facing each other to form a capacitor, and both electrode plates are set relative to each other in accordance with the amount of displacement of a moving object. The amount of mechanical displacement at this time was electrically detected as a change in capacitance of the capacitor.

For example, one electrode plate is arranged on a main scale at equal intervals, and the other electrode plate is arranged on an index facing the main scale at a constant interval, and the main scale or index scale is The movable body is slid parallel to the plate surface in accordance with the displacement of the movable body, and at this time, the amount of displacement of the movable body is detected by the change in capacitance of a capacitor formed between both electrode plates.

However, in the electrostatic encoder in the conventional device, a voltage dividing circuit is formed using a capacitor made of the moving electrode plate, and the displacement amount of the moving object is detected by detecting the voltage dividing ratio that changes according to the capacitor's quietness. was detected. For this reason, in conventional devices, if the distance between the surfaces of the moving electrode plates that form the capacitor changes for some reason and the capacitance of the capacitor changes, or if the power supply voltage applied to the voltage divider circuit changes, In this case, the partial pressure output no longer corresponds accurately to the amount of displacement VC of the moving body, resulting in a drawback that accurate measurement cannot be performed.

Establishment process of the present invention In order to eliminate the above-mentioned conventional drawbacks, five alternating current voltages of different phases are applied to one electrode of the plurality of pairs of '4-likelihood poles, and the tonta signal induced in the other electrode is applied. A capacitive displacement detector has been proposed that detects the relative movement amount by detecting a phase change with respect to a reference phase of an output signal that changes based on the relative movement of both electrodes.

1 and 2 are explanatory diagrams showing the electrode structure of this proposed capacitive displacement detector, in which a fixed plate 10 consisting of a stator or scale plate fixed to the main body of the device is shown.
As shown in FIG. 2, a plurality of transmitting electrodes 12 are arranged at equal intervals on the surface side of the transmitting electrode 12, and a strip-shaped receiving pole 14 is provided in parallel with the transmitting electrodes 12. .

On the other hand, a movable scale plate 16 consisting of a rotor or a movable scale plate is provided facing the fixed plate 10 and interlocked with the movable body. a coupling electrode 18;
Ground 'α poles 20 facing each other across the transmitting electrode 12 and the receiving electrode 14 are alternately arranged along the moving direction of the moving plate 16.

An input section for applying a voltage to each transmitting electrode 12 is provided on the back side of the fixing plate 10, and AC voltage coefficients having different phases are supplied to each transmitting electrode 12 through these input sections. Ru.

On the other hand, a voltage signal corresponding to the voltage signal of each of the transmitting electrodes 12 is induced in the receiving power gi 14 via the combined power supply 18, and therefore, an alternating current voltage with a different phase is applied to each of the transmitting electrodes 12. If the moving object is displaced in this state, an output signal with a phase corresponding to the amount of displacement of the moving object can be obtained from the receiving electrode 14, and the phase of the signal output from the receiving electrode 14 is calculated by the integrator 15. By comparing the displacement with a predetermined reference phase, it is possible to accurately determine the amount of displacement of the moving body without being affected by fluctuations in the original voltage.

In recent years, there has been a demand for miniaturization of devices in order to improve their portability and operability, and when downsizing the proposed device mentioned above, the electrode area of each electrode becomes small, and the gap between the electrodes becomes smaller. The distance becomes narrower. As a result, the signal output voltage of the receiving Ig electrode 14 decreases, resulting in a phenomenon in which the S/N ratio decreases due to the so-called noise mixture. Due to the narrow distance between the poles, the contaminants enter the receiving electrode 14 from the input part of the transmitting electrode 12 to the coupling 1 without passing through the pole 18, which poses a problem in that the detection accuracy of the device deteriorates.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional R problem, and its purpose is to reduce the size of the device and to provide a capacitive type device that can accurately detect the amount of displacement of a moving object. An object of the present invention is to provide a displacement detector.

Structure of the Invention In order to achieve the above object, the present invention includes a fixed plate fixed to a main body, and a movable plate opposite to the fixed plate and movable to the main body. is equipped with a plurality of transmitting electrodes arranged at equal intervals and a band-shaped receiving electrode arranged in parallel with the transmitting and polarizing electrodes, and the movable plate is arranged across the transmitting and receiving electrodes, facing each other and silently looking between the two electrodes. In a capacitive displacement detector that is provided with coupling electrodes for coupling, applies alternating current voltages with different phases to each of the transmitting electrodes, and detects displacement of the moving plate based on the output signal of the receiving electrode, the back surface of the fixed plate is A wiring pattern is formed that commonly connects each transmitting 'dt pole to which an AC voltage of the same phase is applied in the direction in which the transmitting electrodes are arranged, and the wiring pattern on the receiving electrode side or the wiring on the fixed plate side is formed. A transmitter that is in an opposite phase to the transmitter electrode connected to at least one of the pattern electric circuits (position 4 on the back surface of the fixed plate corresponding to
An auxiliary electrode is provided in conduction with the receiving electrode, and the noise mixed into the receiving electrode from the wiring/cross-turn is relaxed and canceled by the correction signal of the auxiliary electrode induced based on the transmitting electrode of the opposite phase. .

Embodiment FIGS. 5 to 8 eζ show the electrode structure formed on the fixed plate of the capacitive displacement detector according to the present invention, and in this embodiment, the structure shown in FIGS. As shown, the fixed plate 10
An example has been shown in which a connection terminal 22 for applying voltage to each transmitting electrode and an auxiliary electrode for canceling out the above-mentioned contamination and noise are provided on the back side of the device. are given the same reference numerals and their explanation will be omitted.

In this embodiment, when applying AC'I4 pressures with different phases to each transmitting electrode 12, each transmitting electrode 12V
Although it is possible to apply alternating current voltages with equal phase differences of the fourth order, as shown in Fig. It is also possible to cancel the noise from the other side with the noise from the other side.

In this embodiment, in FIG.
A connection/e-turn 22 is formed for supplying a common phase voltage to each common phase electrode 12-8, and this connection pattern and each transmission electrode 12-1 to 12-8 are electrically connected by a layer 24. .

In the device shown in FIG. 5, each transmitting electrode 12-1 to 12
-8, voltages with different phases of 0 degrees, 180 degrees, 90 degrees, and 270 degrees are applied sequentially, and here the phase is 0 degrees.
A pair of phase difference pairs is formed by the transmitting electrode 12-4, to which a signal of 180 degrees is input, and the transmitting electrode 12-5, to which a voltage signal with an opposite phase, that is, 180 degrees shifted, is applied. Similarly, the transmitting electrode 12-2 and the transmitting electrode 12-3 and the transmitting electrode 12-6 and the transmitting electrode 12-7 form a phase difference pair, respectively.

The characteristic feature of the present invention is that the input connection A? to each transmitting electrode is made small in size. The turn was provided on the back surface of the fixed plate, and an auxiliary electrode was provided to cancel the noise directly mixed in from the transmitting electrode to the i-electrode, and the correction signal from the auxiliary electrode was used to moderate and cancel out the noise. That's true.

Noise that enters the receiving electrode 14 from the wiring pattern 22 and the turn 22 enters the receiving electrode 14 through two routes. In the /f-turn circuit closest to the knee pole 14, that is, in FIG. 5, the phase is 27.
It can be confirmed from experience that the amount of contamination from the no-el turn circuit 22a on the electrode side of the receiver 51 that supplies the AC voltage of 0' is the largest, and that the amount of contamination from other no-turn circuits is extremely small. Ta. Therefore, in this embodiment, the phase of the voltage led by the patterned conductor 22a closest to the receiving electrode 14 is 7!, which is the opposite phase to the phase of 270° in FIG.
An auxiliary electrode 26 is provided at the back side of the transmitting electrode 12-2 to which the second-stream voltage is applied, that is, in FIG. 5, the 90 degree phase voltage is applied.

Therefore, the closest to the receiving electrode 14 is the turn conductor 2.
The transmitted noise that enters the receiving electrode 14 from the transmitting electrode 12-2 is canceled by a signal having an opposite phase to this transmitted noise, that is, in FIG. Almost the total amount of transmitted noise mixed into the receiving electrode 14 can be canceled out.

On the other hand, the amount of detour noise that detours from the connection pattern 22 onto the surface of the fixed plate 10 and enters the receiving electrode 14 is as follows:
/'f' turn electric path closest to the end surface of the fixed plate 10;
In other words, in Fig. 5, it has been experienced that the amount of contamination from the pattern electric circuit 22b on the fixed plate side, which leads the AC voltage with a phase of 0 degrees, is the largest, and the amount of contamination from other pattern electric circuits is extremely small. I was able to confirm the above. Therefore, in this embodiment, in FIG.
Transmitting electrode 12 to which an AC voltage having a phase of 0 degrees is applied
By providing an auxiliary electrode that conducts with the receiving electrode 14 on the back surface of -1, the patterned electrical path 22 leads to a 0 degree AC voltage.
The iJ function effectively cancels out the noise mixed in from the wiring pattern 22 along the surface of the fixed plate 10 by the correction signal from the auxiliary electrode induced by the transmission type @t2-1. The total amount of detour noise can be effectively offset.

In this embodiment, the detection accuracy can be improved by canceling only one of the transmission noise and the detour noise, but the detection accuracy can be further improved by canceling both noises.

In this way, it is possible to improve the detection accuracy by focusing on the patterned circuit with a large amount of noise mixed in among the circuits of the connection nozzle turf 22 and providing an auxiliary electrode to cancel out the noise from this patterned circuit. In order to cancel out the noise mixed in from other pattern circuits,
It is also possible to provide a corresponding auxiliary electrode for each turn circuit to achieve even more thorough noise cancellation.

Note that in this embodiment, noise that enters the receiving electrode 14 without passing through the normal route, that is, noise that enters the receiving electrode 14 without passing through the normal route,
In order to effectively remove noise other than the voltage signal induced into the receiving electrode 14 via the coupling electrode 18 from the transmitting electrode 12, that is, noise directly mixed into the receiving electrode 14 from the transmitting G pole 12, the J2S wound electrode 12 is used as an auxiliary means. As shown in FIGS. 7 and 8, an isolation ground electrode 28 is provided between the receiving electrode 14 and the receiving electrode 14 to electrically isolate them.

Further, as shown in FIGS. 6 to 8, an auxiliary ground electrode 30 is provided on the back side of the fixed plate 10 at a position outside the input connection part of the transmitting electrode 12, and an input terminal for supplying voltage signals to each transmitting electrode. From part to fixed plate 100? It is possible to prevent noise from entering the receiving electrode]4 by detouring through the receiving electrode.

Furthermore, as shown in FIG. 8, by providing the ground layer 32 on the inner part 91 of the fixed plate 10, noise that enters the receiving electrode 14 from the input part of the transmitting electrode 12 through the inside of the fixed plate 10 can be prevented. By appropriately providing the isolated earth electrode 28, the auxiliary earth electrode 30, and the earth layer 32, in combination with the effect of the auxiliary electrode 26, it is possible to further prevent noise from entering the receiving electrode 14. This makes it possible to detect the movement of a moving object with extremely high accuracy.

Specific Example Next, a specific example in which the device of the present invention is applied to a micrometer will be described.

■Device configuration ill f+ (, 1 Arrangement of fixed plate and moving plate A moving plate is placed on the spindle side and a fixed plate is placed on the main body side.

(2) Arrangement of electrodes and their driving method A set of eight transmitting electrodes was arranged, and five sets were arranged at equal intervals on the circumference of the stake. And j10th order O to the transmitting electrode of each phase,
45 degrees, 90j 1 pay 135 degrees, 180 degrees, 225 degrees, 2
An AC voltage having a phase of 70 degrees was applied, resulting in a so-called three-phase driving force type.

The auxiliary electrode was placed on the back side of the transmitting electrode, where the flat-turn electrical circuit is closest to the receiving positive electrode, and AC voltages of positive phase and reverse phase are applied to <'I.

(3) Outline of the micrometer applicable to this device In this specific example, the electrical angle per rotation of the rotor is 1d 360' X5
=1800° phase change, and in this specific example, 0,5 r4. When applied to a micrometer with a reading of 1 μm, a signal of 500 pulses per rotation of the rotor is output, and in this case, the mechanical angle is 36
The phase of 0° is 360°1500÷5=360°/100
That is, by dividing the 360° phase into 100, a reading of 1 μm is achieved.

(4) Specific design values for the detection unit Distance between the transmitting electrode and the coupling electrode: 1r+x or less Distance between the receiving electrode and the closest connection/gut-turn electric path 77, #:
2 electrode surface of 1 transmitting electrode y * 6 lines 2 Voltage applied to transmitting electrode: 3V"- Distance between transmitting electrode and auxiliary electrode: 1 mm Area of auxiliary's sleep pole: 6 holes ■ Conclusion In the specific example, as a result of the provision of an auxiliary electrode that cancels the mixed noise, the negative influence 7 caused by the noise mixed into the receiving electrode is effectively eliminated compared to the above-mentioned proposed device 6 which does not have the auxiliary electrode. In other words, according to the proposed device that does not have an auxiliary electrode, the noise that enters the receiving electrode from the wiring pattern is approximately 200 mv (S/N0%22
dB), and in this case, the maximum 1 phase black difference is 11 degrees, and the maximum nonlinear error is about 3 μm in a micrometer with a reading of 1 μm having the above configuration.

On the other hand, according to a specific example in which an auxiliary electrode is provided, ih,
From the 'I'A pattern, the noise mixed into the Σ pole has been reduced to 40 rnv (S/N43 G dB), and the maximum phase error at this time is -1z, 2(
g, and the maximum non-linear error id O of the above micrometer can be suppressed to an extremely small error of 6 μm.

Effects of the Invention As explained above, according to the present invention, an auxiliary electrode is provided on the back surface of the fixed plate to cancel out at least one of transmission noise and detour noise. This allows the displacement of a moving body to be detected with extremely high accuracy even though the device is miniaturized.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the electrode structure of a capacitive displacement detector to which the present invention is applied; FIG. 2 is an explanatory diagram of each electrode provided on the fixed plate and moving plate of FIG. 1; The figure is an explanatory diagram showing the connections and input connections for applying AC voltage to each transmitting electrode, Figure 4 is a side view of Figure 3, and Figure 5 is a capacitive displacement detection according to the present invention. An explanatory diagram showing the electrode structure provided on the fixing plate side of the device, FIG. 6 is a sectional view taken along the line A-A in FIG. 5, and FIGS. FIG. 10... Fixed plate, 12... Transmitting electrode, 14
...Receiving electrode, 16...Moving plate, 18...
Coupling electrode, 22... Connection pattern, 26...
Auxiliary electrode, 28...Isolated earth' viewing pole, Agent: Patent attorney Yoshi 1) Kenji (and 1 other person) Fig. 1 6 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Every procedural amendment (snake) Showa June 20, 1958, Mr. Commissioner of the Japan Patent Office1, Indication of the case, 1982 Patent Application No. 898062, Name of the invention Capacitive displacement detector3, Person making the correction A'1 Relationship Patent applicant Address: 5-33-7 Shiba, Minato-ku, Tokyo Name: Sanso Seisakusho Co., Ltd. 1, Agent 5, Column for detailed description of the invention in the specification subject to amendment, Drawings. Figure 5 Procedural amendments spontaneously) July 2Y, 1981 1, Indication of the case 1988 Patent Application No. 89806 2, Name of the invention Capacitance type displacement detector 3, Person making the amendment Relationship with the case Patent Applicant Address: 5-33-7 Shiba, Minato-ku, Tokyo Name: Sanyo Seisakusho Co., Ltd. 4, Agent 5, Subject of amendment: Document III and drawings 6, Contents of amendment (1) Details as attached. correct. (2) Figure 5 is corrected as shown in the attached sheet. (3) Figure 3 is corrected as shown in the attached sheet. Description 1, Title of the invention Capacitive displacement detector 2, Claims (1) A fixed plate fixed to the main body, and a movable plate facing the fixed plate and movably provided to the main body. The surface of the fixed plate is provided with a plurality of transmitting electrodes arranged at equal intervals and a band-shaped signal electrode parallel to the transmitting electrodes, and the movable plate is provided with a plurality of transmitting electrodes arranged at equal intervals and a band-shaped signal electrode arranged in parallel with the transmitting electrodes. Coupling electrodes are provided that face each other and capacitively couple between the two electrodes, and a capacitance that applies AC voltages with different phases to each of the transmitting electrodes and detects the displacement of the moving plate based on the output signal of the receiving electrode. In the mold displacement detector, a wiring pattern is formed on the back side of the fixed plate to commonly connect the transmitting electrodes to which AC voltages with the same phase difference are applied along the arrangement direction of the transmitting electrodes. , the connection on the receiving electrode side p) The back surface of the fixed plate corresponding to the transmitting electrode that is in the opposite phase to the transmitting electrode connected to at least one of the two-turn electric circuit or the wiring pattern electric circuit on the fixed plate side. An auxiliary electrode is provided at a position that is electrically conductive with the receiving electrode, and the noise mixed into the receiving electrode from the connection notch is relaxed and canceled by a correction signal of the auxiliary electrode generated based on the transmitting electrode of the opposite phase. Moe 1 capacitance type displacement detector. (2. In the device according to claim (1), an isolation ground electrode is provided between the transmitting electrode and the output electrode to electrically isolate them.)
Capacitive displacement detector. (3) In the device described in claim (1) or (2), the rear surface of the fixing plate is provided outside the input section (i) of the transmitting electrode.
A capacitive displacement detector characterized by having an auxiliary ground pole at the l1 position. 3. Detailed description of the invention The present invention is a capacitive displacement detector. Capacitance displacement is detected based on the capacitance change between a moving electrode that moves with the moving body and a fixed electrode that is fixed to the main body. BACKGROUND ART Displacement detectors that electrically convert the various displacements of a measuring point or the displacement of a moving table to detect the amount of displacement have been well known, and this type of device is usually used as a device. A movable body movably disposed on a main body, and an encoder that detects the amount of movement of the movable body and converts it into an electrical signal and outputs it.
The electric No. 1 output signal from the encoder is counted by a counting circuit, and the b1 degree value is digitally displayed on the digital display. By the way, the encoders that can be directly connected to the equipment in this building include photoelectric encoders, contact encoders, and i
';ji'+W-type encoder etc. are the circumference 4-1. The twin 6-type encoder has slits provided at equal intervals on the surface of a scale or rotating disk, and nine optical devices and a light receiver that form an optical path through the slits of the scale or rotating disk. The scale or disc is moved or rotated according to the amount of displacement of the moving object, the optical path formed between the redundant lights is turned on and off, and the amount of displacement of the moving object is detected. In the light ′rυ: type encoder, the light emitted j:i
There are disadvantages in that i' consumes a large amount of power, increases the number of times the battery is replaced, and if a battery with a large capacity is used, the entire device becomes large. Furthermore, in order to improve measurement accuracy, it is necessary to provide slits at intervals of several microns on a scale or rotating disk, which is difficult to manufacture and is prone to miscounts due to clearance changes during operation. In addition, contact type encoders use slits, brushes, etc. to detect the displacement of a moving object, so these slits and brushes wear out rapidly, and noise is easily mixed into the measurement signal. On the other hand, electrostatic encoders do not consume much power (like photoelectric encoders), but suffer from wear and tear on the plan, slits, etc. and noise (like contact encoders).
5 Because there are no problems, it has been widely used in detection devices for moving objects in recent years. Conventional technology Conventionally, electrostatic encoders used in such displacement detectors have multiple pairs of electrodes (furnace plate). A capacitor is formed by arranging them facing each other, and both electric orange plates are moved relative to each other in accordance with the amount of displacement of the moving object, and the amount of mechanical displacement at this time is detected automatically as a change in capacitance of the capacitor. For example, one electrode plate was arranged on the main scale at equal intervals, and the other electrode plate was placed on the index facing the main scale at a constant interval. Alternatively, the index scale is slid parallel to the plate surface according to the displacement of the moving body, and at this time, the amount of displacement of the moving body is detected by the change in capacitance of the capacitor formed by both '5't and Wfi plates. However, in the electrostatic encoder in the conventional device, a capacitor consisting of the moving electrode plate is used to form a voltage divider circuit, and the voltage divider ratio that changes according to the capacitance of the capacitor is detected to detect the moving object. For this reason, with conventional devices, if the distance between the surfaces of the moving electrode plates that form the capacitor changes for some reason and the static E capacity of the capacitor changes, or if the partial pressure When the power supply voltage applied to the circuit changes, the partial voltage output no longer corresponds accurately to the amount of displacement of the moving body, resulting in a drawback that accurate measurement cannot be performed. In order to eliminate the above-mentioned conventional drawbacks, alternating current voltages of different phases are applied to one electrode of the electrode pair consisting of the above-mentioned number pair, the voltage signal induced in the other electrode is detected, and the relative relationship between the two electrodes is A capacitive displacement detector has been proposed that detects a phase change with respect to a reference phase of an output signal that changes based on movement to determine the amount of relative movement. An explanatory diagram showing the electrode structure of a capacitive displacement detector is shown, and a fixed plate 10 consisting of a stator or scale plate fixed to the device main body side is shown.
As shown in FIG. 2, on the 0 surface side, a plurality of transmitting electrodes 12 are arranged at equal intervals, and a band-shaped receiving electrode 14 is provided in parallel to the transmitting electrodes 12. On the other hand, a movable plate 16 consisting of a rotor or a movable scale plate is provided opposite the fixed plate 10 and is interlocked with the movement r. a coupling electrode 18 disposed facing each other across the transmitting electrode 12 and the receiving electrode 14; and the transmitting electrode 12 and the receiving electrode 1.
The ground electrodes 20 are arranged opposite to each other across the ground electrodes 4 and are arranged alternately in the moving direction of the moving plate 16. An input section for applying a voltage to each transmitting electrode 12 is provided on the back side of the fixed plate 10, and AC voltage signals having different phases are supplied to each transmitting electrode 12 via these input sections. On the other hand, a voltage signal corresponding to the voltage signal of each transmitting electrode 12 is induced in the receiving electrode 14 via the coupling electrode 18,
Therefore, if the moving body is displaced while applying alternating current voltages with different phases to each of the transmitting electrodes 12, an output signal with a phase corresponding to the amount of displacement of the moving body can be obtained from the receiving electrodes 14, and this reception room The integrator 15 processes the phase of the signal output from the $i 14 and compares it with a predetermined reference phase to accurately measure the amount of displacement of the moving body without being affected by fluctuations in power supply voltage, etc. becomes possible. In recent years, in order to improve the portability and operability of device a, there has been a demand for miniaturization of the device itself.When downsizing the proposed device mentioned above, the electrode area of each electrode becomes smaller, and the gap between the electrodes becomes smaller. The distance becomes narrower. Therefore, the signal output voltage of the receiving electrode 14 decreases, resulting in a phenomenon in which the S/N ratio decreases due to the so-called noise mixture. Due to this narrowing of the distance between the electrodes, the transmitting electrode 120
From the input section to one receiving electrode 1 without passing through the coupling electrode 18
4, which caused a problem in that the detection accuracy of the device deteriorated. Purpose of the Invention The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to miniaturize the device and provide a capacitive displacement device that can accurately detect the amount of displacement of a moving object. The purpose is to provide a detector. Structure of the Invention In order to achieve the above object, the present invention includes an identification plate fixed to a main body, and a movable plate facing the fixed plate and movably provided to the main body. Arranged at equal intervals!
(A plurality of transmitting electrodes arranged in a row and a band-shaped receiving electrode arranged in parallel with the transmitting electrodes are provided, and the moving plate is provided with the transmitting electrodes and the receiving electrodes. A capacitive displacement detector is provided with electrodes, applies alternating current voltages with different phases to each of the transmitting electrodes, and detects the displacement of the moving plate based on the output signal of the receiving electrode.
A U-turn is formed on the back side of the fixing plate to commonly connect the transmitting electrodes to which AC voltages of the same phase are applied in the direction in which the transmitting electrodes are arranged.
(A small number of connections 16 and 16/Mulberry/ξ-line circuits on the 'turn circuit or the fixed plate side (in any case, the fixed plate corresponding to the transmitting electrode that is in the opposite phase to the transmitting electrode connected to one of the circuits) An auxiliary electrode that conducts with the receiving electrode is provided on the back side of the
The present invention is characterized in that noise mixed into the reception 'FIL' pole from the wiring pattern is relaxed and canceled by a correction signal of the auxiliary electrode induced based on the transmission electrode of the opposite phase. Embodiment FIGS. 5 to 8 show the electrode structure formed on the fixed plate of the capacitive displacement detector according to the present invention, and in this embodiment, the electrode structure shown in FIGS. , an example is shown in which a connection turn 22 for applying a voltage to each transmitting electrode and an auxiliary electrode for canceling out the above-mentioned mixed noise are provided on the back side of the fixed plate 10, and the above-mentioned proposed device Components that are the same as those in the above are given the same reference numerals and their explanations will be omitted. In this embodiment, when applying alternating current voltages with different phases to each transmitting electrode 12, alternating current voltages having the same phase difference are sequentially applied to each transmitting electrode 12. In FIG. 5 of this embodiment, each transmitting electrode 12-1 to 12
A wiring pattern 22 is formed for supplying a voltage of a co-tracing phase to each of the common phase electrodes 12-8 and 12-8, and this wiring pattern and each of the transmitting electrodes 12-1 to 12-8 are electrically connected by a layer 24. In the device shown in FIG. 5, each transmitting electrode 12-1 to 1
Voltages with different phases of 0 degrees, 9 ohm, lso degrees, and 270 degrees are sequentially applied to 2-8, and a signal with a phase of 0 degrees is input here. 5 and the transmitter 1E pole 12-7 to which a voltage signal with an opposite phase, that is, shifted by 180 degrees, is applied, forming an advantageous phase difference pair. Transmitting electrode 12
-4, the transmitting electrode 12-1, and the transmitting electrode 12-3 form a phase difference pair, respectively. The main feature of the present invention is that, in order to reduce the external dimensions, each turn for the input connection to each transmitting electrode is provided on the back of the fixed plate, and the receiving terminal is connected from the transmitting electrode to the receiving terminal. An auxiliary electrode was provided to dampen the noise that directly enters the 41jζ, and a correction signal from the auxiliary electrode was used to moderate and cancel out the FjiI noise. Noise that enters the receiving electrode 14 from the wiring pattern 22 enters the receiving electrode 14 through two routes, but among these, the amount of transmitted noise that enters the receiving electrode 14 through the wiring pattern 22 and the inside of the fixed plate 10 is The closest chisel-turn circuit, that is, the chisel-turn circuit 22a on the receiving electrode side that supplies an alternating current voltage with a phase of 270° in FIG.
It has been confirmed from experience that the amount of contamination from the wire is the largest, and the amount of contamination from other chisel-turn electrical circuits is small. The position on the back side of the transmitter 41 to which the voltage phase conducted by the multi-turn electric path 22a, which is 270 degrees in FIG. An auxiliary electrode 26 is provided at a position on the back surface of the transmitting electrode 12-2 to which the phase voltage of is applied.
The incubator noise received from 2a and mixed into the electrode 14 is caused by a signal having an opposite phase to this transmitted noise, that is, a correction signal from the auxiliary electrode 26 induced by the transmitting electrode 12-2 as shown in FIG. This cancels out almost the total amount of transmitted noise that enters the receiving electrode 14 from the wiring pattern 22. On the other hand, the detour noise that is received along the fixed plate 100σJ from the connection pattern 22 and enters the 5th electrode 14 is the Noreen electric path closest to the end surface of the fixed plate 10, that is, the 5th electrode 14. In the figure, the amount of contamination from the patterned circuit 22b of the fixed plate (II) which leads an AC voltage with a phase of 0 degrees is the largest, and the amount of contamination from the patterned circuit of (Ii12) is extremely small. Therefore, in this example, in FIG. An alternating current voltage having a transmitting voltage of 12-3 is applied to the reverse side of pole 12-3.
By providing an auxiliary electrode connected to the ilr pole 14 and 47, a pattern that leads to a 0 degree AC voltage can be used to eliminate noise that may be mixed in by the auxiliary electrode 22b by the correction signal from the auxiliary electrode induced by the transmitting electrode 12-3. It is possible to effectively cancel the wiring pattern 22 and fixing plate 1.
Almost the total amount of detour noise mixed along 001m can be effectively canceled out. In this embodiment, the detection accuracy can be improved by canceling out only one of the transmission noise and the detour noise, but the detection accuracy is further improved by canceling out both noises. :It is possible to improve the detection accuracy by focusing on the pattern circuit in J-5 that has a large amount of noise mixed in among the circuits in the wiring pattern 22, and providing an auxiliary electrode to cancel out the noise from this pattern circuit. However, in this case, in order to cancel out the noise mixed in from other pattern circuits,
It is also possible to provide a corresponding auxiliary electrode for each patterned circuit to achieve even more thorough noise cancellation. 6. In this embodiment, noise that enters the receiving electrode 14 without passing through the normal route, that is,
In order to effectively remove noise other than the voltage signal generated from the voltage signal from the transmitting electrode 12 to the receiving electrode 14 via the coupling electrode 18, that is, the noise directly mixed into the receiving voltage signal 14 from the transmitting electrode 12, the transmitting electrode is used as an auxiliary means. 12 and the receiving electrode 14, as shown in FIGS. 7 and 8, an isolation ground electrode 28 is provided to electrically isolate the two. As shown in Figure 8, on the back side of the tilted fixed plate 1°, a grounding wire 30 is provided on the outside of the input connection part of the transmitting electrode 120, and an input part that supplies a voltage signal to each transmitting electrode. It is possible to prevent noise from detouring along the surface of the fixing plate 10 and entering the receiving electrode 14. Furthermore, as shown in FIG. 8, by providing the ground layer 32 inside the fixing plate 10, It is also possible to prevent noise from entering the receiving electrode 14 from the input part of the transmitting electrode 120 through the inside of the fixed plate 10, by providing the above-mentioned isolated ground electrode 28, auxiliary grounding cable 30, and grounding layer 32 as appropriate. This, combined with the effect of the auxiliary electrode 26 of A 111, further enhances the effect of preventing noise from entering the received amount 4*, 14, making it possible to detect the amount of transferred Liυ1 of the transferred sweetfish body with extremely high accuracy. Specific Example Next, a specific example in which the device 4 of the present invention is applied to a micrometer will be described. ■ Device configuration () Arrangement of fixed plate and movable plate The movable plate is disposed on the spin Ple side and the fixed plate is disposed on the main body side. (2) Arrangement of electrodes and their driving method A set of 8 transmitting electrodes was arranged, and 5 sets were arranged at equal intervals on the circumference of the stator.
AC voltages with phases of 3°, 90°, 135°, 180°, 225°, and 270° are applied.
It uses a phase drive method. Further, the auxiliary electrode was provided at a position on the back surface of the transmitting electrode to which an AC voltage having an opposite phase to the voltage phase led by the patterned electric path, which is also close to the receiving electrode and ify, was applied. (3) Outline of micrometer applicable to this device In this specific example, the electrical angle per rotation of the rotor is 360'X5=18
00'' phase change, and in this specific example, 0
．． When applied to a 1 μm reading micrometer with a 5 mm pitch, a signal of 500 norus per rotor rotation is output, and in this case, the phase of mechanical angle 360' is 360°1500÷5=360°/ 100, i.e.
By dividing the 360° phase by 100, a reading of 1 μm is achieved. (4) Specific design values for the detection unit Distance between the transmitting electrode and the coupling electrode: 1 mm or less Distance between the receiving electrode and the nearest connecting no-turn electric path = 2 electrode area of 1 transmitting electrode 6 - To the transmitting electrode Applied voltage: 3 ■ Distance between transmitting electrode and auxiliary electrode: 1 mm Electrode area of auxiliary electrode = 6 - ■ Result In this specific example, as a result of providing an auxiliary electrode to cancel out the mixed noise, the auxiliary electrode Compared to the above-mentioned proposed device that does not have the above-mentioned proposed device, it was possible to effectively eliminate the adverse effects of noise mixing into the received amount of 4Wi. In other words, it does not have an auxiliary electrode. According to the proposed device &4
The noise that enters the receiving electrode from the k-line pattern is approximately 20
0 mv (S/N-, -22 dB), and at this time, the maximum phase error is 11 degrees, and the 1tt of the above configuration
For a micrometer with an m reading, the maximum nonlinear error is about 3 μm. On the other hand, according to a specific example in which an auxiliary electrode is provided, the noise that enters the receiving electrode from the connection node is 40 mv.
(S / N = 36 dB), the maximum phase error at this time is 2.2 degrees, and in the above-mentioned micrometer, the nonlinear error is extremely small at 0.6 μm. I was able to hold it down. As described in detail, according to the present invention, an auxiliary electrode is provided in the curve of the fixed plate to cancel out at least one of the transmission noise and the detour noise, and as a result, the noise from the wire connection is mixed into the receiving electrode. This allows the displacement of the moving body to be detected at an extremely high degree of 11 Y degrees, even though the armament is made smaller. Fig. 1 is an explanatory diagram showing the electrode structure of a capacitive single-piece displacement detector to which the present invention is applied, and Fig. 2 shows the activation of each electrode provided on the fixed plate and the displacement plate in Fig. 1. Figure 4 is a clear diagram showing the wiring pattern for applying AC voltage to each transmitting electrode and its input connection, Figure 4 is a side view of Figure 3, and Figure 5 Explanatory diagram showing the electrode structure provided on the identification plate 1111) of the l# capacitance displacement detector, No. 6
The figure is a top view of A-1 in Fig. 5, and No. 7121, No. 8 L\] is another embodiment showing the structure provided on the fixing plate of the present invention. This is an example diagram. 10...Fixing plate, 12...Transmission electric connection, 14
...-receiving electrode, 16... moving plate, ]8...
Coupling electrode, 22... Connection pattern, 26...
Auxiliary electrode, 28... Isolated earth electrode, 30...
・Auxiliary ground voltage 4. Agent -Ji Urijukichi 1) Ishido Ni (1 other person)

Claims (1)

[Claims] (1) It has a fixed plate fixed to the main body, and a movable plate facing the fixed plate and movably provided to the main body, and the movable plate is arranged at equal intervals on the surface of the fixed plate. A plurality of transmitting electrodes and a band-shaped receiving electrode are provided in parallel with the transmitting electrode, and a coupling electrode is provided on the movable plate and facing the transmitting electrode and the receiving electrode to capacitively couple the two electrodes. In the capacitive displacement detector which applies alternating current voltages with different phases to each of the transmitting electrodes and detects the displacement of the movable plate based on the output signal of the receiver frame, the V on the back side of the fixed plate is connected to the transmitter. A connection/f-turn is formed to commonly connect the 8 tung poles of each transmitter to which an AC voltage with the same phase difference is applied after 7 days in the electrode arrangement direction, and the connection/f-turn on the receiving electrode side Or, an auxiliary electrode that is electrically connected to the receiving electrode is provided on the back side of the fixed plate corresponding to the transmitting electrode that is in the opposite phase to the transmitting electrode connected to at least one of the fixed plate wiring pattern electric circuits. A displacement detector of the Shushe type displacement detector is characterized in that the noise mixed into the receiving electrode from the wiring/cross-turn is relaxed and canceled by the correction signal of the auxiliary electrode induced based on the transmitting electrode of the opposite phase. +2) The device according to claim (1) is characterized in that a ground electrode is provided between the main fFi pole and the output electrode with a gap that electrically isolates them. Capacitive displacement detector. (3) In the device according to claim (1) or (2), the back side of the fixing plate has a position 1 outside the input part of the transmitting electrode.
A static [6 valley type displacement detector] characterized in that an auxiliary grounding shaft is provided at 1 (1-).