JPH07260891A - Method and apparatus for measuring voltage - Google Patents

Abstract

PURPOSE:To provide method and apparatus for measuring the voltage of an object using a voltage sensor comprising an electrooptic element with no effect of drift component or specific low frequency noise. CONSTITUTION:A voltage sensor 4 comprises a switch means S0 for short- circuiting a measuring electrode 21 disposed closely to, or touching, an object 104 and a reference electrode 20 being applied with a reference voltage. When the switch means S0 is turned ON to irradiate an object 104 with a measuring light M, the polarized state of the measuring light M is detected and employed as a reference polarization state in the measurement of voltage of the object 104.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage measuring method and apparatus, and more particularly, it has a voltage sensor using an electro-optical element, and the voltage sensor is placed close to or in contact with the object to be measured. The present invention relates to a voltage measuring method and device for measuring a voltage.

[0002]

2. Description of the Related Art Conventionally, there is a method of using a voltage sensor using an electro-optical element as a method of measuring a voltage induced in a measurement object such as an internal wiring of an LSI or an external electrode. The principle of this method is as follows. That is, when a voltage sensor using an electro-optical element is brought close to or in contact with a measurement target, a voltage or an electric field from the measurement target induces a change in birefringence in the crystal of the electro-optical element. This change in birefringence is detected by irradiating the electro-optical element with light such as laser light to detect the change in the polarization state, and indirectly measures the voltage of the measurement target.

A conventional voltage sensor using an electro-optical element will be described with reference to FIG. The voltage sensor shown in FIG.
The electro-optical element 102 and the reference electrode 100 formed on the surface of the electro-optical element 102 opposite to the surface facing the measurement target.
And a measurement electrode 101 which is formed on the surface of the electro-optical element 102 facing the measurement target and is brought into proximity or contact with the measurement target 104 during voltage measurement.

Here, the electro-optical element 102 measures the voltage of the measuring object 104 when the measuring electrode 101 is brought into contact with the measuring object 104, and measures the measuring electrode 101 when the measuring electrode 101 is brought close to the measuring object 104. When a voltage is applied to the measurement electrode 101 by the electric field from the object 104, the birefringence inside the crystal changes (Pockels effect)
Have.

The measuring electrode 101 is made of a material that reflects the measuring light M, which is a laser light of a semiconductor laser or the like. The reference electrode 100 is made of a material that transmits the measuring light M. Further, the reference voltage generated by the reference voltage source 23 is applied to the reference electrode 100, and the reference voltage referred to when measuring the voltage of the measurement target 104 is applied to the reference electrode 100. Is being applied.

Next, voltage measurement using the voltage sensor shown in FIG. 9 will be described. First, a reference voltage is applied to the reference electrode 100, and the measurement light M is irradiated to the electro-optical element 102 in a state where the measurement electrode 101 is not brought close to or in contact with the measurement object 104, and the polarization state thereof is detected.

Next, in order to measure the voltage of the measuring object 104, the measuring electrode 101 is brought close to or in contact with the measuring object 104, the measuring light M is applied to the electro-optical element 102, and its polarization state is detected.

Then, the measuring electrode 101 is connected to the measuring object 104.
The polarization state of the measuring light M when brought into proximity with or in contact with
The polarization state of the measurement light M when the measurement electrode 101 is not brought close to or in contact with the measurement target 104 is compared, and the voltage of the measurement target 104 is derived from the change.

The above-described voltage measurement by the conventional voltage sensor using the electro-optical element has a feature that it is not necessary to connect an electrode or the like to the object to be measured. However, on the other hand, when measuring a minute voltage, the change in birefringence due to the electro-optical effect is extremely small, and therefore, there is a disadvantage that it is susceptible to various noises.

If the noise is pure shot noise or thermal noise, the measurement accuracy can be improved by repeatedly measuring and taking the averaging. However, when a drift component or a specific low-frequency noise is mixed in the noise, the reference voltage used as a reference for voltage measurement fluctuates, and thus the simple addition averaging does not sufficiently improve the measurement accuracy.

As a method of removing the drift component and the specific low frequency noise, conventionally, the measurement interval is set to a time interval in which the drift component can be ignored, and the measurement target is changed from the change of the detection amount due to the change of the phase of the voltage signal of the measurement target. Method of detecting the voltage of the
A method has been performed in which the voltage signal measured by applying F is modulated, and the voltage of the measurement target is measured from the change in the measured voltage according to the modulation.

Further, the voltage signal applied to the measurement object is periodically modulated, and only the frequency component having the period is detected by a lock-in amplifier or the like to remove noise components having frequency components other than the frequency component. Then, a method of improving the S / N ratio has also been adopted.

[0013]

However, according to the method of detecting the voltage of the measurement target from the change of the detected amount due to the change of the phase of the voltage signal of the measurement target, the DC component contained in the measured voltage signal is However, there is a problem that it is regarded as a drift component and is removed.

Further, the voltage signal applied to the measuring object is O
According to the method of modulating the voltage signal measured by turning off and on, there is a problem that the whole measuring device becomes large-scale and the measuring method becomes complicated.

Therefore, an object of the present invention is to measure the voltage of an object to be measured by a voltage sensor using an electro-optical element,
It is an object of the present invention to provide a voltage measurement device capable of measuring a voltage without being affected by a drift component or a specific low frequency noise without increasing the size and complexity of the measurement device.

[0016]

In order to solve the above-mentioned problems, the invention according to claim 1 has an electro-optical element having a measurement electrode which is brought into proximity to or in contact with an object to be measured and a reference electrode to which a reference voltage is applied. In the voltage measurement method of irradiating a voltage sensor using the measuring light (M), detecting a change in the polarization state of the measuring light that has passed through the electro-optical element to measure the voltage of the measuring object, the measuring electrode (21 ) And a reference electrode (2
0) is short-circuited to detect the polarization state of the measurement light (M) when the measurement light (M) is irradiated, and the voltage of the measurement target (104) is measured with the detected polarization state as the reference polarization state. To be configured.

According to a second aspect of the present invention, a voltage sensor using an electro-optical element having a measurement electrode that is brought close to the object to be measured and a reference electrode to which a reference voltage is applied is irradiated with measurement light, and the electro-optical element is connected to the voltage sensor. In a voltage measuring device that detects a change in the polarization state of passing measurement light and measures the voltage of a measurement target, a voltage sensor (4) includes a measurement electrode (21) that is close to the measurement target (104), and a reference voltage. And a switch means (S ₀ ) for short-circuiting the reference electrode (20) to which is applied.

According to a third aspect of the present invention, a voltage sensor using an electro-optical element having a measurement electrode to be brought into contact with an object to be measured and a reference electrode to which a reference voltage is applied is irradiated with measurement light, and the electro-optical element is attached to the voltage sensor. In a voltage measuring device that detects a change in the polarization state of passing measurement light to measure a voltage of a measurement target, a voltage sensor (4a) includes a measurement electrode (21) that contacts the measurement target (104), and a reference voltage. second switch means but connecting the first switching means for short-circuiting the reference electrode applied (20) (S _0), the reference electrode a reference voltage source for generating a reference voltage (23) (20) (S 1 )
And are configured.

[0019]

According to the invention described in claim 1, the measuring electrode (2
1) and the reference electrode (20) are short-circuited and the measurement light (M) is irradiated with the measurement light (M), the polarization state of the measurement light (M) is detected,
Next, the voltage of the measurement target (104) is measured with the detected polarization state as the reference polarization state.

Therefore, the measuring electrode (21) and the reference electrode (2
0) is short-circuited and the measurement light (M) is irradiated with the measurement light (M), the polarization state of the measurement light (M) is set to the reference polarization state, and thus a voltage that is not affected by drift components, specific low-frequency noise, or the like. It becomes possible to measure.

According to the second aspect of the present invention, the switch means (S ₀ ) includes the measurement electrode (21) which is brought close to the measurement object (104) and the reference electrode (2) to which the reference voltage is applied.
0) and are short-circuited.

Therefore, the measurement electrode (21) and the reference electrode (2
0) is short-circuited and the measurement light (M) is irradiated with the measurement light (M), and the voltage of the measurement target (104) is measured using the polarization state of the measurement light (M) as a reference polarization state. It is possible to measure voltage without being affected by noise or the like.

According to the third aspect of the present invention, the first switch means (S ₀ ) includes the measurement electrode (21) to be brought into contact with the measurement object (104) and the reference electrode (20) to which the reference voltage is applied. Short circuit and.

The second switch means (S ₁ ) connects a reference voltage source (23) for generating a reference voltage to the reference electrode (20). Therefore, the measurement electrode (21) is measured (104)
Since the reference voltage is not applied to the measurement target (104) even when the voltage is measured by touching the measurement target (104), the measurement target (104) is protected and the influence of the drift component, the specific low frequency noise, or the like is prevented. It is possible to measure the voltage without receiving it.

[0025]

The preferred embodiments of the present invention will now be described with reference to the drawings. (I) Configuration of Voltage Measuring Device According to First to Third Embodiments First, the overall configuration of the voltage measuring device according to the first to third embodiments of the present invention will be described with reference to FIG.

The voltage measuring device shown in FIG. 1 includes a CPU 1 for controlling the entire voltage measuring device, a semiconductor laser 3 for emitting a measuring light M, and a drive section 2 for driving the semiconductor laser 3.
The voltage sensor 4 (4a, which detects the voltage of the measurement target 104,
4b) and the voltage sensor 4 based on the control of the CPU 1.
A sensor controller 5 for outputting a sensor control signal E for controlling (4a, 4b), and a voltage sensor 4 (4a,
4b) a polarization detector 6 for detecting the polarization state of the measuring light M and converting it into a detection signal which is an electric signal, an amplifier 7 for amplifying the detection signal, and a signal for A / D conversion or the like for the detection signal. The signal processing unit 8 performs processing and outputs it to the CPU 1, and a timing generation unit 9 that generates a timing signal for driving the driving unit 2 based on a trigger signal from the measurement object 104.

Next, the operation will be described. The timing generator 9 emits the measurement light M on the basis of a trigger signal output from the measurement object 104 in order to apply a voltage to the measurement object 104 and emit the measurement light M. It generates a signal and outputs it to the CPU 1.

The CPU 1 outputs the timing signal to the drive unit 2 with a necessary delay. The drive unit 2 drives the semiconductor laser 3 based on the input timing signal,
The measurement light M is emitted.

Here, the measuring light M is used when the voltage to be measured applied to the measuring object 104 is a pulse wave.
A pulsed laser having a resolution capable of measuring it and having a period synchronized with the above timing signal is used, and when the voltage to be measured is a continuous wave, continuously oscillated laser light is used.

The polarization state of the measuring light M passing through the voltage sensor 4 (4a, 4b) is detected by the polarization detector 6,
The electric signal is converted into a detection signal, amplified by the amplifier 7, processed by the signal processor 8 such as A / D conversion, and input to the CPU 1. The CPU 1 converts this signal into a voltage value.

The sensor controller 5 synchronizes with the above-mentioned timing signal and synchronizes with the voltage sensors 4 (4a, 4a, 4a) described later.
The sensor control signal E for controlling the switch S ₀ (S ₁ , S ₂ ) installed in b) is output, and the switch S of the voltage sensor 4 (4a, 4b) is output based on the sensor control signal E. The switching of ₀ (S ₁ , S ₂ ) is controlled. The timing signal is generated in the timing generation unit 9 based on the trigger signal output from the measurement target 104, but is generated in the timing generation unit 9 based on the signal output from the CPU 1 and is generated in the measurement target 104. It is also possible to input the timing and take the timing with the measuring light M.

The invention described in claims 1 to 3 relates to the voltage sensor 4 (4a, 4b). (II) First Embodiment Next, a first embodiment corresponding to the invention described in claim 1 or 2 will be described with reference to FIGS. 1 and 2.

FIG. 2 shows the configuration of the voltage sensor 4 according to the first embodiment of the present invention. In the first embodiment, the measuring object 104 is not contacted with the voltage sensor 4
It shows the case of measuring the voltage of.

The voltage sensor 4 shown in FIG. 2 measures the electro-optical element 22, the reference electrode 20 formed on the surface of the electro-optical element 22 opposite to the surface facing the measurement object 104, and the electro-optical element 22. A measurement electrode 21 which is formed on a surface facing the object 104 and is close to the object 104 to be measured during voltage measurement.
And a switch S ₀ that short-circuits the reference electrode 20 and the measurement electrode 21.

Specifically, the switch S ₀ can be composed of a FET, a photoconductive element, and a minute switch that conducts electricity mechanically. The sensor control signal E from the sensor controller 5 turns ON / OFF the switch S _0. Is controlled.

Here, the electro-optical element 22 is the measurement electrode 2
When 1 is brought close to the measuring object 104, the measuring object 10
When a voltage is induced in the measuring electrode 21 by the electric field from 4, the birefringence inside the crystal has an electro-optical effect. As a specific material for the electro-optical element 22, gallium arsenide is suitable.

The measuring electrode 21 is made of a material that reflects the measuring light M, which is laser light from a semiconductor laser or the like.
The reference electrode 20 is made of a material that transmits the measuring light M. Further, the reference voltage generated by the reference voltage source 23 is applied to the reference electrode 20 and the reference voltage referred to when measuring the voltage of the measurement target 104 is applied. Is being applied.

Next, a voltage measuring method using the voltage sensor shown in FIG. 2 will be described. First, a reference voltage is applied to the reference electrode 20, the switch S ₀ is turned on, and the reference electrode 20 and the measurement electrode 21 are short-circuited. And switch S
_The measurement light M is emitted with the ₀ being ON, and the polarization state is detected by the polarization detector 6. As a result, the polarization state (the polarization state when the reference electrode 20 and the measurement electrode 21 have the same potential) serving as a reference for voltage measurement is detected and converted into the voltage value V ₀ .

In this case, the voltage value V ₀ does not include the influence of noise such as a drift component.
When the reference polarization state is detected, the voltage to be measured is next applied to the measurement object 104, and the switch S ₀ is turned off. Then, the measurement light M is emitted with the switch S ₀ kept OFF, and the polarization state is detected by the polarization detector 6. Accordingly, based on the change in the birefringence of the electro-optical element 22 caused by the voltage induced in the measurement electrode 21 by the electric field from the measurement object 104, the measurement light M corresponding to the voltage induced in the measurement electrode 21 is generated. The polarization state is detected and converted into a voltage value V ₁ .

Then, by subtracting the voltage value V ₀ from the voltage value V ₁ , the voltage change due to the voltage applied to the measurement object 104, which is based on the state in which the switch S ₀ of the voltage of the measuring electrode 21 is turned ON, is changed. The voltage detected and applied to the measurement target 104 is obtained based on the detected voltage.

According to the first embodiment described above, the reference electrode 20 and the measurement electrode 21 can be provided without increasing the size and complexity of the measuring device.
The voltage value measured when the potential difference between
Since the voltage of the measurement target 104 is measured using the voltage value when the switch S ₀ is turned on as the reference voltage, the voltage of the measurement target 104 can be measured without being affected by noise such as a drift component. (III) Second Embodiment Next, a second embodiment corresponding to the invention described in claim 3 will be described with reference to FIGS. 1 and 3.

FIG. 3 shows the configuration of the voltage sensor 4a according to the second embodiment of the present invention. The second embodiment shows a case where the measuring electrode 21 of the voltage sensor 4a is brought into contact with the measuring object 104 to measure the voltage of the measuring object 104.

The same members as those in the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted. The voltage sensor 4a shown in FIG. 3 is the voltage sensor 4 of the first embodiment.
In addition to the above configuration, a switch S ₁ that connects the reference electrode 20 and the reference voltage source 23 is provided. The switch S ₁ is controlled by the sensor control signal E from the sensor controller 5 similarly to the switch S ₀ in the first embodiment. However, the switch S ₀ and the switch S ₁ are alternately turned on / off.
It is controlled to be turned off. That is, the switch S
When ₀ is ON, the switch S ₁ is turned OFF, the switch S ₀ is the time of OFF, is controlled to switch S ₁ is turned ON.

Next, a voltage measuring method using the voltage sensor 4a shown in FIG. 3 will be described. First, measurement target 1
Switch S ₀ with the voltage to be measured applied to 04.
Is turned on and the switch S ₁ is turned off, and the reference electrode 2
0 and the measurement electrode 21 are short-circuited. Then, the switch S ₀
Is turned on and the measuring light M is irradiated with the switch S ₁ kept off, and the polarization state is detected by the polarization detector 6. As a result, the polarization state (the polarization state when the reference electrode 20 and the measurement electrode 21 have the same potential) serving as a reference for voltage measurement is detected and converted into the voltage value V ₀ .

This voltage value V ₀ does not include the influence of noise such as drift component as in the first embodiment.
Further, at this time, since the reference voltage is not applied to the measurement target 104, the measurement target 104 is protected.

When the reference polarization state is detected,
The switch S ₀ is turned off and the switch S ₁ is turned on. Then, the switch S ₀ is turned off, and the switch S ₁
The measurement light M is irradiated with the switch ON, and the polarization state is detected by the polarization detector 6.

As a result, the measuring electrode 21 becomes the measuring object 10
4 and the polarization state in the state where the reference voltage is applied to the reference electrode 20 is detected. Therefore, the measurement target 104
Of the measurement electrode 2 based on the change in the birefringence of the electro-optical element 22 caused by the voltage of the measurement electrode 21 that is the same voltage as
The polarization state of the measuring light M corresponding to the voltage of 1 is detected,
The voltage value is converted to V ₁ .

Then, by subtracting the voltage value V ₀ from the voltage value V ₁ , the voltage change caused by the voltage applied to the measurement object 104 is changed with reference to the state in which the switch S ₀ of the voltage of the measuring electrode 21 is turned on. The voltage detected and applied to the measurement target 104 is obtained based on the detected voltage. (IV) Third Embodiment Next, another embodiment (hereinafter referred to as a third embodiment) corresponding to the invention described in claim 3 will be described with reference to FIGS. 1 and 4.

FIG. 4 shows the configuration of the voltage sensor 4b according to the third embodiment of the present invention. The third embodiment has a probe electrode 24 that is brought into contact with a measurement target, and instead of the switch S ₁ of the second embodiment, the probe electrode 24 and the measurement electrode 2
The case where the switch S ₂ is provided between the _two is shown.

The same members as those in the second embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. The switch S ₂ is controlled by the sensor control signal E from the sensor controller 5 similarly to the switch S ₁ in the second embodiment. That is, when the switch S ₀ is ON, the switch S ₂ is OFF, and when the switch S ₀ is OFF, the switch S ₂ is ON.

Next, a voltage measuring method using the voltage sensor 4b shown in FIG. 4 will be described. Here, the probe electrode 24 is in contact with the measurement target 104. First, similarly to the second embodiment, the switch S ₀ is turned on with the voltage to be measured applied to the measurement object 104, and the switch S ₀ is turned on.
_{When 2} is turned off, the reference electrode 20 and the measurement electrode 21 are short-circuited, the polarization state serving as the reference for voltage measurement (the polarization state when the reference electrode 20 and the measurement electrode 21 have the same potential) is detected, and the voltage value V ₀ is determined. obtain.

This voltage value V ₀ does not include the influence of noise such as drift components as in the first embodiment.
At this time, since the reference voltage is not applied to the measurement target 104, the measurement target 104 is protected.

When the reference polarization state is detected,
Next, switch S ₀ is turned off and switch S ₂ is turned on.
To Then, the measurement light M is irradiated, and the polarization state is detected by the polarization detector 6. As a result, the measurement electrode 2
The probe electrode 24 short-circuited with 1 contacts the measurement object 104, the measurement electrode 21 has the same voltage as the measurement object 104, and the polarization state in the state where the reference voltage is applied to the reference electrode 20 is detected. Therefore, similarly to the second embodiment, the polarization state of the measuring light M corresponding to the voltage of the measuring electrode 21 is detected and converted into the voltage value V ₁ .

Then, by subtracting the voltage value V ₀ from the voltage value V ₁ , the voltage change due to the voltage applied to the measurement object 104, which is based on the state in which the switch S ₀ of the voltage of the measurement electrode 21 is ON, is used as a reference. The voltage detected and applied to the measurement target 104 is obtained based on the detected voltage.

According to the second and third embodiments described above, the voltage value measured when the potential difference between the reference electrode 20 and the measurement electrode 21 is 0, that is, the voltage value when the switch S ₀ is turned on. Since the voltage of the measurement target 104 is measured as the reference voltage, the voltage of the measurement target 104 can be measured without being affected by noise such as a drift component without increasing the size and complexity of the measuring device. Moreover, since the reference voltage is not applied to the measurement target 104, the measurement target 104 can be protected. (V) Configuration of Voltage Measuring Device According to Fourth to Sixth Embodiments Next, the overall configuration of the voltage measuring devices according to the fourth to sixth embodiments of the present invention will be described with reference to FIG.

In FIG. 5, the same members as those of the voltage measuring device (see FIG. 1) according to the first to third embodiments of the present invention are designated by the same reference numerals, and detailed description thereof will be omitted. In addition to the voltage measuring device shown in FIG. 1, the voltage measuring device shown in FIG. 5 has a switch control light C (described later) in which the switch operation corresponding to the switches S _{0 to} S ₂ in the first to third embodiments is described C _1, C _2, C _3, C ₄₎ a voltage sensor 10 (10a which is controlled by, and 10b), a semiconductor laser 13 for emitting light C switch control _{(C 1, C 2, C} 3, C 4) And a drive unit 1 for driving the semiconductor laser 13.
2 and a switch controller 11 for controlling the drive unit 12 under the control of the CPU 1.

Next, the operation will be described. In addition to the voltage measuring device of FIG. 1, the voltage measuring device shown in FIG.
The switch controller 11 is controlled based on the timing signal from the timing generator 9.

The switch controller 11 is based on the control of the CPU 1 and uses the switch control lights C (C ₁ , C ₂ , C ₃ ,
A control signal for controlling the emission of C ₄ ) is output to the drive unit 2, the drive unit 2 drives the semiconductor laser 13 based on the input control signal, and the switch control light C (C ₁ ,
C ₂ , C ₃ , and C ₄ ) are emitted.

The switch control lights C (C ₁ , C ₂ ,
The semiconductor laser 13 used as C ₃ and C ₄ ) is
It has a characteristic of causing a photoconductive effect in the electro-optical element 32 described later. (VI) Fourth Embodiment Next, a fourth embodiment, which is a modification of the first embodiment, will be described with reference to FIGS. 5 and 6.

In this embodiment, the operation corresponding to the switch S ₀ in the voltage sensor 4 of the first embodiment is realized by using the switch control light C. In this embodiment, the same members as those in the first embodiment shown in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

The voltage sensor 10 shown in FIG. 6 measures the electro-optical element 32, the reference electrode 30 formed on the surface of the electro-optical element 32 opposite to the surface facing the object 104 to be measured, and the electro-optical element 32. Formed on the surface facing the target 104,
Measurement electrode 31 that is brought close to the measurement target 104 during voltage measurement
It is composed of and.

Here, the electro-optical element 32 has the same electro-optical effect as the electro-optical element 22 in the first embodiment, and when irradiated with the switch control light C, electric charge is excited in that portion, There is a photoconductive effect in which the portion irradiated with the switch control light C becomes conductive.

The measuring electrode 31 is made of a material that reflects the measuring light M, which is laser light from a semiconductor laser or the like.
In this embodiment, as in the first embodiment, the measuring electrode 3
1 is not contacted with the measuring object.

The reference electrode 30 is made of a material such as a transparent conductive film that transmits the measuring light M and the switch controlling light C, and a reference voltage is applied to the reference electrode 30.

Next, voltage measurement using the voltage sensor shown in FIG. 6 will be described. First, a reference voltage is applied to the reference electrode 30 and the switch control light C is irradiated as shown in FIG. 6 to excite charges due to the photoconductive effect in the irradiated portion, whereby the reference electrode 30 and the measurement electrode 31 are excited. Short circuit. Then, the measurement light M is emitted while the switch control light C is still emitted, and the polarization state is detected by the polarization detector 6.

As a result, the voltage value V ₀ in the polarization state which is the reference for voltage measurement is obtained. This voltage value V ₀ does not include the influence of noise such as a drift component as in the above-described embodiments.

When the reference polarization state is detected,
Next, the voltage to be measured is applied to the measurement target 104, and the irradiation of the switch control light C is stopped. Then, the photoconductive effect is lost and the reference electrode 30 and the measurement electrode 31 are insulated.

After that, the measuring light M is irradiated again, and the polarization state is detected by the polarization detector 6. Accordingly, based on the change in the birefringence of the electro-optical element 32 caused by the voltage induced in the measurement electrode 31 by the electric field from the measurement object 104, the measurement light M corresponding to the voltage induced in the measurement electrode 31 is generated. The polarization state is detected and converted into a voltage value V ₁ .

Then, the voltage applied to the measurement object 104 can be obtained by subtracting the voltage value V ₀ from the voltage value V ₁ . According to the fourth embodiment described above, in addition to the same effect as the first embodiment, the photoconductive effect of the electro-optical element 32 is used as a switch, so that the reference electrode 30 and the measurement can be performed without providing a mechanical switch or the like. The electrodes 31 can be short-circuited,
A switching operation with a high switching speed can be realized with a simple circuit configuration. (VII) Fifth Embodiment Next, a fifth embodiment which is a modification of the second embodiment will be described with reference to FIGS.

In this embodiment, the voltage sensor 4a of the second embodiment is used.
The operations corresponding to the switches S ₀ and S ₁ in the above are realized by using the switch control lights C ₁ and C ₂ .
In this embodiment, the same members as those in the fourth embodiment shown in FIG. 6 are designated by the same reference numerals, and detailed description thereof will be omitted.

The voltage sensor 10a shown in FIG. 7 is formed on the electro-optical element 32 and a part of the surface of the electro-optical element 32 opposite to the surface facing the object to be measured 104 (see FIG. 7B). Reference electrode 33 and reference electrode 33 of electro-optical element 32
Is formed on the same surface as the surface on which the reference electrode 33 is formed.
Reference electrode 34 insulated from (see FIG. 7B)
And a measurement electrode 35 formed on a part of the surface of the electro-optical element 32 facing the measurement target 104 (see FIG. 7B) and contacting the measurement target 104 during voltage measurement. A slit-like gap is provided between the reference electrodes 33 and 34, as shown in FIG.

Here, similarly to the fourth embodiment, the electro-optical element 32 has a photoconductive effect for the switch control lights C ₁ and C _{2 in} addition to the electro-optical effect. The reference electrode 33 is
It is made of a material such as a transparent conductive film that transmits the measuring light M and the switch controlling light C ₁ .

A reference voltage is applied to the reference electrode 34. Next, a voltage measuring method using the voltage sensor 10a shown in FIG. 7 will be described. _First , in a state in which a voltage to be measured is applied to the measurement object 104, the portion including the reference electrode 33 and the measurement electrode 35 is irradiated with the switch control light C ₁ as shown in FIG. 7, and the reference electrode is caused by the photoconductive effect. 33 and the measuring electrode 35 are short-circuited. At this time, the switch control light C
_{Since 2} is not illuminated, the reference electrodes 33 and 34 are insulated. Then, as shown in FIG. 7, the measuring light M is applied to the portion of the reference electrode 33, and the polarization state thereof is detected by the polarization detector 6. As a result, the polarization state serving as the reference for voltage measurement (the polarization state when the reference electrode 33 and the measurement electrode 35 have the same potential) is detected and converted into the voltage value V ₀ .

This voltage value V ₀ does not include the influence of noise such as drift components as in the above-described embodiments. At this time, since the reference voltage is not applied to the measurement target 104, the measurement target 104 is protected.

If the reference polarization state is detected,
The irradiation of the switch control light C ₁ is stopped and the switch control light C ₂ is irradiated. As shown in FIG. 7, the switch control light C ₂ is irradiated so as to include a part of the reference electrode 33, a part of the reference electrode 34, and a part of the electro-optical element sandwiched between the reference electrodes 33 and 34. . As a result, the reference electrode 33 and the measurement electrode 35 are insulated, and the reference electrodes 33 and 34 are isolated.
Is rendered conductive by the photoconductive effect of the electro-optical element 32, and a reference voltage is applied to the reference electrode 33.

Next, the measurement light M is applied to the reference electrode 33 as shown in FIG. 7 while the switch control light C ₂ is still applied, and the polarization state is detected by the polarization detector 6.
Accordingly, based on the change in the birefringence of the electro-optical element 32 caused by the voltage of the measurement electrode 35 that is the same as the voltage of the measurement target 104, the measurement light M corresponding to the voltage applied to the measurement electrode 35 is generated. The polarization state is detected and converted into a voltage value V ₁ .

Then, the voltage applied to the measurement object 104 can be obtained by subtracting the voltage value V ₀ from the voltage value V ₁ . (VIII) Sixth Embodiment Next, a sixth embodiment which is a modification of the third embodiment will be described with reference to FIGS. 5 and 8.

In this embodiment, the voltage sensor 4b of the third embodiment is used.
The operations corresponding to the switches S ₀ and S ₂ in the above are realized by using the switch control lights C ₃ and C ₄ .
In this embodiment, the same members as those in the fifth embodiment shown in FIG. 7 are designated by the same reference numerals, and detailed description thereof will be omitted.

The voltage sensor 10b shown in FIG. 8 is a reference formed on the electro-optical element 32 and a part of the surface of the electro-optical element 32 opposite to the surface facing the object to be measured (see FIG. 8B). The electrode 36 and the measurement electrode 37 formed on a part of the surface of the electro-optical element 32 facing the measurement target (see FIG. 8B).
And a probe electrode 38 which is insulated from the measurement electrode 37 and is brought into contact with the measurement target. Measuring electrode 37
As shown in FIG. 8B, a slit-shaped gap is provided between the probe electrode 38 and the probe electrode 38.

Here, in the same manner as the fifth embodiment, the electro-optical element 32 has the switch control light C _{3 in} addition to the electro-optical effect.
And C ₄ have a photoconductive effect. Reference electrode 36
Is a measuring light M such as a transparent conductive film and a switch controlling light C.
It is made of a material that transmits ₃ and a reference voltage is applied to the reference electrode 36.

Next, voltage measurement using the voltage sensor 10b shown in FIG. 8 will be described. Here, the probe electrode 3
8 is in contact with the measurement object 104. First, in a state in which a voltage to be measured is applied to the measurement target 104, as shown in FIG.
As shown in ( ₃₎ , the switch control light C ₃ is applied to the portion including the reference electrode 36 and the measurement electrode 37, and the reference electrode 36 and the measurement electrode 37 are short-circuited by the photoconductive effect. At this time, since the switch control light C ₄ is not emitted, the measurement electrode 37
And the probe electrode 38 is insulated. Then, the measurement light M is applied to the portion of the reference electrode 36 as shown in FIG.
The polarization state is detected by the polarization detector 6. As a result, the polarization state that serves as a reference for voltage measurement (the polarization state when the reference electrode 36 and the measurement electrode 37 have the same potential) is detected and converted into the voltage value V ₀ .

This voltage value V ₀ does not include the influence of noise such as drift components as in the above-described embodiments. At this time, the reference voltage is not applied to the measurement target 104, and the measurement target 104 is protected.

If the reference polarization state is detected,
The irradiation of the switch control light C ₃ is stopped and the switch control light C ₄ is irradiated. As shown in FIG. 8, the switch control light C ₄ does not include the reference electrode 36, but does not include the reference electrode 36, the measurement electrode 37, the probe electrode 38, the measurement electrode 37, and the probe electrode 38. It is illuminated to include an optical element. , Thereby, the reference electrode 36 and the measurement electrode 37 are insulated, and the measurement electrode 37 and the probe electrode 3
8 is made conductive by the photoconductive effect of the electro-optical element 32.

Next, the measurement light M is applied to the portion of the reference electrode 36 while the switch control light C ₄ is still applied, and the polarization state is detected by the polarization detector 6. This corresponds to the voltage applied to the probe electrode 38 (measurement electrode 37) based on the change in the birefringence of the electro-optical element 32 caused by the voltage of the probe electrode 38 that is the same as the voltage of the measurement target 104. The polarization state of the measuring light M is detected and converted into a voltage value V ₁ .

Then, the voltage applied to the measurement object 104 can be obtained by subtracting the voltage value V ₀ from the voltage value V ₁ . According to the fifth and sixth embodiments described above, in addition to the same effects as the second and third embodiments, the photoconductive effect of the electro-optical element 32 is used as a switch,
A switching operation with a high switching speed can be executed by a simple circuit configuration without providing a mechanical switch or the like.

[0086]

As described above, according to the first aspect of the invention, the measurement electrode (21) and the reference electrode (20) are short-circuited and the measurement light (M) is irradiated. The polarization state of the light (M) is detected, and the voltage of the measurement target (104) is measured using the detected polarization state as the reference polarization state. Therefore, the measurement electrode (21) and the reference electrode (20) are short-circuited. Measurement light (M) when irradiated with measurement light (M)
The polarization state of is the reference polarization state, and the measuring device is upsized.
It is possible to perform voltage measurement without being affected by drift components, specific low-frequency noise, etc. without complication.

According to the second aspect of the invention, the measurement electrode (21) which is brought close to the measurement object 104 by the switch means (S ₀ ) and the reference electrode (20) to which the reference voltage is applied.
Since they are short-circuited, the measurement electrode (21) and the reference electrode (2
0) is short-circuited and the measurement light (M) is irradiated with the measurement light (M), and the voltage of the measurement target (104) can be measured using the polarization state of the measurement light (M) as a reference polarization state, thus increasing the size of the measurement device. Therefore, it is possible to perform voltage measurement without being affected by drift components, specific low frequency noise, etc. without complication.

According to the third aspect of the present invention, the measurement electrode (21) brought into contact with the measurement object (104) by the first switch means (S ₀ ) and the reference electrode (20) to which the reference voltage is applied. Since the reference voltage source (23) for generating the reference voltage by the second switch means (S ₁ ) is connected to the reference electrode (20), the measurement electrode (21) is brought into contact with the measurement target (104). Even when measuring the voltage, the reference voltage is not applied to the measurement target (104), and while protecting the measurement target (104), the drift device or the specific low component can be reduced without increasing the size and complexity of the measurement device. It is possible to measure voltage without being affected by frequency noise.

[Brief description of drawings]

FIG. 1 is a diagram showing a voltage measuring device according to first to third embodiments of the present invention.

FIG. 2 is a diagram showing a voltage sensor according to a first embodiment of the present invention.

FIG. 3 is a diagram showing a voltage sensor according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a voltage sensor according to a third embodiment of the present invention.

FIG. 5 is a diagram showing a voltage measuring device according to fourth to sixth embodiments of the present invention.

FIG. 6 is a diagram showing a voltage sensor according to a fourth embodiment of the present invention.

FIG. 7 is a diagram showing a voltage sensor according to a fifth embodiment of the present invention.

FIG. 8 is a diagram showing a voltage sensor according to a sixth embodiment of the present invention.

FIG. 9 is a diagram showing a voltage sensor of a conventional voltage measuring device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... CPU 2, 12 ... Drive part 3 ... Semiconductor laser 4, 4a, 4b, 10, 10a, 10b ... Voltage sensor 5 ... Sensor controller 6 ... Polarization detector 7 ... Amplifier 8 ... Signal processor 9 ... Timing generator 11 ... switch controller 13 ... semiconductor laser 20, 30, 33, 34, 36 ... reference electrode 21, 31, 35, 37 ... measurement electrode 22, 32 ... electro-optical element 23 ... reference voltage source 24, 38 ... probe electrode 100 ... reference Electrode 101 ... Measuring electrode 102 ... Electro-optical element 103 ... Reference voltage source 104 ... Measurement object M ... Measurement light C, C ₁ , C ₂ , C ₃ , C ₄ ... Switch control light E ... Sensor control signal S ₀ , S ₁ , S ₂ ... switch

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 16, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

Next, in order to measure the voltage of the measuring object 104, the measuring electrode 101 is brought close to or in contact with the measuring object 104, the measuring light M is applied to the electro-optical element 102, and its polarization state is detected . Detects the voltage of the measurement target 104
It

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[0008]

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

The above-described voltage measurement by the prior art voltage sensor using the electro-optical element has a high time resolution.
It has features such as being obtained . However, on the other hand, when measuring a minute voltage, the change in birefringence due to the electro-optical effect is extremely small, and therefore, there is a disadvantage that it is susceptible to various noises.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

[0013]

However, in the method of detecting the voltage of the measurement target from the change of the detection amount due to the change of the phase of the voltage signal of the measurement target, the measurement target drive device and the measurement target voltage are detected.
There is a problem in that the measurement requires a complicated operation of the fixed device, which makes the measurement complicated .

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

According to a second aspect of the invention, the object to be measured is close to
Or , irradiating the measuring light to the voltage sensor using the electro-optical element having the measuring electrode to be brought into contact and the reference electrode to which the reference voltage is applied, and detecting the change in the polarization state of the measuring light passing through the electro-optical element. In a voltage measuring device that measures the voltage of a measurement target, the voltage sensor (4) includes a measurement target (10
4) has a switch means (S ₀ ) for short-circuiting the measuring electrode (21) brought into proximity with or in contact with the reference electrode (20) to which the reference voltage is applied.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

According to the second aspect of the present invention, the switch means (S ₀ ) is applied with the reference voltage and the measurement electrode (21) which is brought into proximity or contact with the measurement object (104). The reference electrode (20) is short-circuited.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

The voltage measuring device shown in FIG. 1 includes a CPU 1 for controlling the entire voltage measuring device, a semiconductor laser 3 for emitting a measuring light M, and a drive section 2 for driving the semiconductor laser 3.
The voltage sensor 4 (4a, which detects the voltage of the measurement target 104,
4b) and the voltage sensor 4 based on the control of the CPU 1.
A sensor controller 5 for outputting a sensor control signal E for controlling (4a, 4b), and a voltage sensor 4 (4a,
4b) a polarization detector 6 for detecting the polarization state of the measuring light M and converting it into a detection signal which is an electric signal, an amplifier 7 for amplifying the detection signal, and a signal for A / D conversion or the like for the detection signal. A signal processor 8 which performs processing and outputs it to the CPU 1 and a timing processor ( not shown) which generates a timing signal for driving the drive unit 2 based on a trigger signal from the measurement object 104.
And a ming generation unit .

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

Next, the operation will be described.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

The CPU 1 is a trigger from the measurement object 104.
The signal has a delay preset by the timing generator.
To generate a timing signal and output it to the drive unit 2.
It The drive unit 2 is a semiconductor device according to the timing signal.
The laser 3 is driven to generate the measuring light M. here,
Usually, the measuring light M is pulsed light.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

The measuring light M is not pulsed light.
It is also possible to oscillate as continuous light and measure the voltage.
It In this case, the drive unit 2 continuously drives the semiconductor laser 3.
And the timing signal is not the drive unit 2
It is input to the processor 8 and controls the timing of signal processing.
It will be.

[Procedure Amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction content]

The sensor controller 5 is a switch S ₀ (S) (S) installed on a voltage sensor 4 (4a, 4b) described later.
₁ , S ₂ ) to output a sensor control signal E, and based on this sensor control signal E, the voltage sensor 4
The switching of the switches S ₀ (S ₁ , S ₂ ) of (4a, 4b) is controlled. The above timing signal is based on a trigger signal measured 104 outputs timing
Although it is generated in the generation unit , it may be generated in the timing generation unit based on the signal output from the CPU 1 and input to the measurement target 104 to take timing with the measurement light M.

[Procedure Amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

Here, the electro-optical element 22 is the measurement electrode 2
When 1 is brought close to the measuring object 104, the measuring object 10
When a voltage is induced in the measuring electrode 21 by the electric field from 4, the birefringence inside the crystal has an electro-optical effect. A specific material for the electro-optical element 22 is gallium arsenide or the like.

[Procedure Amendment 14]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction content]

[0039] In this case Te odor, if the polarization state as the standards is detected, by applying a voltage to then measure the measurement target 104, the switch S ₀ turned OFF. Then, the measurement light M is emitted with the switch S ₀ kept OFF, and the polarization state is detected by the polarization detector 6. Thereby, the measurement electrode 21 is generated by the electric field from the measurement target 104.
The basis of the change in the birefringence of the electro-optical element 22 due to the induced voltage, the polarization state of the measuring beam M corresponding to the voltage induced in the measuring electrode 21 is detected and converted into a voltage value V ₁ It

[Procedure Amendment 15]

[Document name to be amended] Statement

[Correction target item name] 0040

[Correction method] Change

[Correction content]

Then, by subtracting the voltage value V ₀ from the voltage value V ₁ , the voltage change due to the voltage applied to the measurement object 104, which is based on the state in which the switch S ₀ of the voltage of the measuring electrode 21 is turned ON, is changed. The voltage detected and applied to the measurement target 104 is obtained based on the detected voltage. here,
Refer to the control signal of the switch S ₀ for the output of the polarization detector 6.
Detected as a signal by a lock-in amplifier (not shown)
To improve the S / N (Signal / Noise) ratio.
Both are possible.

[Procedure Amendment 16]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction content]

According to the first embodiment described above, the reference electrode 20 and the measurement electrode 21 can be provided without increasing the size and complexity of the measuring device.
The voltage value measured when the potential difference between
Since the voltage of the measurement target 104 is measured using the voltage value when the switch S ₀ is turned on as the reference voltage, the voltage of the measurement target 104 can be measured without being affected by noise such as a drift component. The measurement electrode 21 is connected to the measurement object 104.
When touching the switch, turn on the switch S ₀
In addition, the voltage of the reference voltage source 23 is directly applied to the measurement target 104.
However, the voltage measurement is more accurate.
The advantage is that (III) Second Embodiment Next, a second embodiment corresponding to the invention described in claim 3 will be described with reference to FIGS. 1 and 3.

[Procedure Amendment 17]

[Document name to be amended] Statement

[Name of item to be corrected] 0045

[Correction method] Change

[Correction content]

[0045] In addition, at this time, the reference voltage is measured 10
4 is not applied, the measurement object 104 is protected.

[Procedure 18]

[Document name to be amended] Statement

[Correction target item name] 0048

[Correction method] Change

[Correction content]

Then, by subtracting the voltage value V ₀ from the voltage value V ₁ , the voltage change caused by the voltage applied to the measurement object 104 is changed with reference to the state in which the switch S ₀ of the voltage of the measuring electrode 21 is turned on. The voltage detected and applied to the measurement target 104 is obtained based on the detected voltage. here,
The output of the polarization detector 6 is sent to the control signals of the switches S ₀ and S ₁ .
Signal as a reference signal can be detected by a lock-in amplifier.
With, it is possible to improve the S / N ratio. (IV) Third Embodiment Next, another embodiment (hereinafter referred to as a third embodiment) corresponding to the invention described in claim 3 will be described with reference to FIGS. 1 and 4.

[Procedure Amendment 19]

[Document name to be amended] Statement

[Correction target item name] 0052

[Correction method] Change

[Correction content]

At this time, since the reference voltage is not applied to the measuring object 104, the measuring object 104 is protected.

[Procedure amendment 20]

[Document name to be amended] Statement

[Correction target item name] 0054

[Correction method] Change

[Correction content]

Then, by subtracting the voltage value V ₀ from the voltage value V ₁ , the voltage change due to the voltage applied to the measurement object 104, which is based on the state in which the switch S ₀ of the voltage of the measurement electrode 21 is ON, is used as a reference. The voltage detected and applied to the measurement target 104 is obtained based on the detected voltage. here,
The output of the polarization detector 6 is sent to the control signals of the switches S ₀ and S ₁ .
Signal as a reference signal can be detected by a lock-in amplifier.
With, it is possible to improve the S / N ratio.

[Procedure correction 21]

[Document name to be amended] Statement

[Name of item to be corrected] 0057

[Correction method] Change

[Correction content]

Next, the operation will be described. In addition to the voltage measuring device of FIG. 1, the voltage measuring device shown in FIG.
The switch controller 11 is controlled.

[Procedure correction 22]

[Document name to be amended] Statement

[Correction target item name] 0066

[Correction method] Change

[Correction content]

[0066] Thus, the voltage value V ₀ in the polarization state as a reference for voltage measurement Ru sought.

[Procedure amendment 23]

[Document name to be amended] Statement

[Correction target item name] 0067

[Correction method] Change

[Correction content]

When the reference polarization state is detected,
Next, the irradiation of the switch control light C is stopped. Then, the photoconductive effect is lost and the reference electrode 30 and the measurement electrode 31 are insulated.

[Procedure correction 24]

[Document name to be amended] Statement

[Correction target item name] 0069

[Correction method] Change

[Correction content]

Then, the voltage applied to the measurement object 104 is obtained by subtracting the voltage value V ₀ from the voltage value V ₁ . Here, the output of the polarization detector 6 is switched
Lock-in amplifier with control signal of control light C as reference signal
To improve the S / N ratio by detecting
Is also possible. According to the fourth embodiment described above, in addition to the same effects as the first embodiment, the electro-optical element 3 functions as a switch.
Since the photoconductive effect of No. 2 is used, the reference electrode 30 and the measurement electrode 31 can be short-circuited without providing a mechanical switch or the like, and the stray capacitance is small and the switching speed is fast with a simple circuit configuration. The operation can be realized. (VII) Fifth Embodiment Next, a fifth embodiment which is a modification of the second embodiment will be described with reference to FIGS.

[Procedure correction 25]

[Document name to be amended] Statement

[Correction target item name] 0073

[Correction method] Change

[Correction content]

A reference voltage is applied to the reference electrode 34. Next, a voltage measuring method using the voltage sensor 10a shown in FIG. 7 will be described. _First , as shown in FIG. 7 , the portion including the reference electrode 33 and the measurement electrode 35 is irradiated with the switch control light C _1, and the reference electrode 33 and the measurement electrode 35 are short-circuited by the photoconductive effect. At this time, the switch control light C
_{Since 2} is not illuminated, the reference electrodes 33 and 34 are insulated. Then, as shown in FIG. 7, the measuring light M is applied to the portion of the reference electrode 33, and the polarization state thereof is detected by the polarization detector 6. As a result, the polarization state serving as the reference for voltage measurement (the polarization state when the reference electrode 33 and the measurement electrode 35 have the same potential) is detected and converted into the voltage value V ₀ .

[Procedure Amendment 26]

[Document name to be amended] Statement

[Correction target item name] 0074

[Correction method] Change

[Correction content]

At this time, since the reference voltage is not applied to the measuring object 104, the measuring object 104 is protected.

[Procedure Amendment 27]

[Document name to be amended] Statement

[Correction target item name] 0077

[Correction method] Change

[Correction content]

Then, the voltage applied to the measurement object 104 can be obtained by subtracting the voltage value V ₀ from the voltage value V ₁ . Here, the output of the polarization detector 6 is
The control signals of the switch control lights C ₁ and C ₂ are used as reference signals.
The lock-in amplifier detects the S / N
It is also possible to improve the ratio. (VIII) Sixth Embodiment Next, a sixth embodiment which is a modification of the third embodiment will be described with reference to FIGS. 5 and 8.

[Procedure correction 28]

[Document name to be amended] Statement

[Correction target item name] 0081

[Correction method] Change

[Correction content]

Next, voltage measurement using the voltage sensor 10b shown in FIG. 8 will be described. Here, the probe electrode 3
8 is in contact with the measurement object 104. First , Fig. 8
As shown in ( ₃₎ , the switch control light C ₃ is applied to the portion including the reference electrode 36 and the measurement electrode 37, and the reference electrode 36 and the measurement electrode 37 are short-circuited by the photoconductive effect. At this time, since the switch control light C ₄ is not emitted, the measurement electrode 37
And the probe electrode 38 is insulated. Then, the measurement light M is applied to the portion of the reference electrode 36 as shown in FIG.
The polarization state is detected by the polarization detector 6. As a result, the polarization state that serves as a reference for voltage measurement (the polarization state when the reference electrode 36 and the measurement electrode 37 have the same potential) is detected and converted into the voltage value V ₀ .

[Procedure correction 29]

[Document name to be amended] Statement

[Correction target item name] 0082

[Correction method] Change

[Correction content]

[0082] At this time, the reference voltage to the measurement target 104 is not applied, the measurement object 104 is protected.

[Procedure amendment 30]

[Document name to be amended] Statement

[Correction target item name] 0085

[Correction method] Change

[Correction content]

Then, the voltage applied to the measurement object 104 can be obtained by subtracting the voltage value V ₀ from the voltage value V ₁ . Here, the output of the polarization detector 6 is
The control signals of the switch control lights C ₃ and C ₄ are used as reference signals.
The lock-in amplifier detects the S / N
It is also possible to improve the ratio. Above 5th and 6th
According to the embodiment, in addition to the same effects as those of the second and third embodiments, the photoconductive effect of the electro-optical element 32 is used as a switch, so that a simple circuit configuration is provided without providing a mechanical switch or the like. It is possible to perform a switching operation with a small stray capacitance and a high switching speed.

[Procedure correction 31]

[Document name to be amended] Statement

[Correction target item name] 0087

[Correction method] Change

[Correction content]

According to the second aspect of the present invention, the measuring electrode (21) which is brought into proximity to or in contact with the measuring object 104 by the switch means (S ₀ ) and the reference electrode (reference electrode) to which the reference voltage is applied. 20) is short-circuited, so that the polarization state of the measurement light (M) when the measurement electrode (21) and the reference electrode (20) are short-circuited and irradiated with the measurement light (M) is set as a reference polarization state. Since the voltage of (104) can be measured, the voltage can be measured without being affected by a drift component, specific low frequency noise, etc. without increasing the size and complexity of the measuring device.

[Procedure correction 32]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Explanation of reference numerals] 1 ... CPU 2, 12 ... Driving unit 3 ... Semiconductor lasers 4, 4a, 4b, 1010a, 10b ... Voltage sensor 5 ... Sensor controller 6 ... Polarization detector 7 ... Amplifier 8 ... Signal processor 11 ... switch controller 13 ... semiconductor laser 20, 30, 33, 34, 36 ... reference electrode 21, 31, 35, 37 ... measurement electrode 22, 32 ... electro-optical element 23 ... reference voltage source 24, 38 ... probe electrode 100 ... reference Electrode 101 ... Measuring electrode 102 ... Electro-optical element 103 ... Reference voltage source 104 ... Measurement object M ... Measurement light C, C ₁ , C ₂ , C ₃ , C ₄ ... Switch control light E ... Sensor control signal S ₀ , S ₁ , S ₂ ... switch

[Procedure amendment 33]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure amendment 34]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H01L 21/66 C 7630-4M

Claims (3)

[Claims] 1. A voltage sensor using an electro-optical element having a measurement electrode that is brought into proximity to or in contact with a measurement target and a reference electrode to which a reference voltage is applied, is irradiated with measurement light, and the measurement is performed after passing through the electro-optical element. A voltage measuring method for detecting a change in the polarization state of the measuring light to measure the voltage of the measuring object, wherein the measuring electrode (21) and the reference electrode (20) are short-circuited to irradiate the measuring light (M). The voltage measuring method is characterized in that the polarization state of the measuring light (M) at that time is detected, and the voltage of the measurement object (104) is measured with the detected polarization state as a reference polarization state. 2. The measuring light irradiating a voltage sensor using an electro-optical element having a measuring electrode close to an object to be measured and a reference electrode to which a reference voltage is applied, and the measuring light passing through the electro-optical element. In the voltage measurement device that detects the change in the polarization state of the measurement target and measures the voltage of the measurement target, the voltage sensor (4) is applied with a measurement electrode (21) that is brought close to the measurement target (104) and a reference voltage. A voltage measuring device comprising switch means (S ₀ ) for short-circuiting the reference electrode (20). 3. The measurement light irradiating a voltage sensor using an electro-optical element having a measurement electrode to be brought into contact with a measurement target and a reference electrode to which a reference voltage is applied, and the measurement light passing through the electro-optical element. In the voltage measuring device that detects the change in the polarization state of the measurement target and measures the voltage of the measurement target, the voltage sensor (4a) is applied with the measurement electrode (21) that contacts the measurement target and a reference voltage. First switch means (S ₀ ) for short-circuiting the reference electrode (20) and second switch means (S ₁ ) for connecting a reference voltage source (23) for generating the reference voltage to the reference electrode (20). A voltage measuring device comprising: