JP3538181B2 - Photoelectric field sensor and photoelectric field detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric magnetic field sensor and a photoelectric magnetic field detecting device for obtaining magnetic field information and electric field information at low cost and with high accuracy.

[0002]

2. Description of the Related Art In recent years, with the development of electronic equipment, it has become necessary to measure a magnetic field and an electric field leaking from an integrated circuit board or the like to the surroundings with high accuracy. As conventional electromagnetic field sensors for acquiring magnetic field information and electric field information, for example, the following three conventional examples are known.

First, as a first conventional example, there is one using a loop sensor shown in FIG. This loop sensor performs a balance / unbalance conversion by receiving a magnetic field with a metal loop constituted by a metal arc 112 and a coaxial cable 118, and performs one end of the arc 112 and a gap 114 via a gap 114. A signal is transmitted to the measuring instrument by a coaxial cable 118 which is opposed and is in a short-circuit state S at the other end of the arc-shaped member 112, and a detection result is obtained.

As a second conventional example, as shown in FIG. 14, a metal arc member 122 and a pair of coaxial cables 1 are provided.
It is known that a metal loop constituted by 26 picks up magnetic field information and electric field information. In this example, in order to separate the magnetic field information and the electric field information, both ends of the arc-shaped member 122 and the ends of the pair of coaxial cables 126 have gaps 1 respectively.
24 and has a sealed dead loop. The coaxial cable 126 is connected to the hybrid circuit 128 having the matching termination 128A.
This conventional example is a so-called double-gap loop sensor connected to a.

On the other hand, as a third conventional example, as shown in FIG.
4 and the electrode 134
Consisting of metal elements 138 connected to
Some have an optical modulator 140. In this conventional example, laser light was sent from the laser light source 142 to the optical modulator 140 by the polarization plane maintaining optical fiber 146 via the polarization compensator 144, and was obtained by the single mode optical fiber 148 on the downstream side. It has a structure using laser light such that light is converted into an electric signal by the light detector 150 and displayed on the level meter 152.

[0006]

However, the first and the second
In the conventional example, since the metal loop picks up the magnetic field information and the electric field information at the same time, the magnetic field information and the electric field information are mixed, and it is difficult to separate and measure these with high accuracy. Obtaining high-precision measurement results because the function of balanced / unbalanced conversion is inadequate and, for example, signal disturbance occurs due to noise received while an electric signal is traveling along a transmission path such as a coaxial cable. Could not be done.

Further, in the second conventional example having a double gap loop sensor, a hybrid circuit having high separation performance is required to separate magnetic field information and electric field information. In addition, to receive a magnetic field in a metal loop (balance), to transmit a signal to a measuring instrument or measuring instrument by a coaxial cable (unbalance),
It is necessary to provide a loop / unbalanced converter (balun) that functions with high accuracy. For this reason, the conventional example requires a device that functions as a hybrid circuit or a balanced / unbalanced converter, and thus has a drawback that the manufacturing cost increases.

On the other hand, including the third conventional example, there is also a disadvantage that the measurement accuracy is low as a result of the disturbance of the surrounding electromagnetic field due to the metal part existing in the sensor part or the metal part such as the coaxial cable for signal transmission. Had. That is, in each of the conventional examples, high-precision measurement was difficult due to factors such as the sensor itself. The present invention has been made in view of the above-described circumstances, and has as its object to provide a photoelectric magnetic field sensor and a photoelectric magnetic field detecting device capable of separating and acquiring magnetic field information and electric field information with high accuracy at low cost.

[0009]

According to a first aspect of the present invention, there is provided an optoelectronic magnetic field sensor having a pair of gaps, a conductor pattern formed in an annular shape of a conductive material, and a pair of electric patterns inserted into the pair of gaps. And an optical crystal.

According to the photoelectric field sensor of the first aspect, a pair of gaps are provided in the conductor pattern formed in a ring shape by using a conductive material, and a pair of electro-optic crystals are respectively provided in the pair of gaps. The configuration has been inserted. That is, when the pair of electro-optic crystals are inserted into the pair of gaps, for example, the optical axis direction is set to the same direction along the conductor pattern, The directions can be opposite to each other along the pattern. Therefore, by arranging this photoelectric magnetic field sensor as a sensor body at a position to be measured and allowing light such as laser light to pass through the pair of electro-optic crystals, it is possible to separate and acquire only magnetic field information or only electric field information. It becomes.

Accordingly, since the photoelectric field sensor according to the present invention uses light such as laser light,
Since there is no need for a coaxial cable and the metal portion is only a conductor pattern, disturbance in the surrounding electromagnetic field is less likely to occur. Furthermore, since light is used, there is no possibility that the function of the balanced / unbalanced conversion becomes insufficient, and there is no possibility that the electric signal receives noise during the transmission along the transmission path. That is, as a result, highly accurate measurement is possible.

On the other hand, for example, by adjusting the direction of the optical axis of the electro-optic crystal, magnetic field information and electric field information can be easily separated, so that connection to a hybrid circuit or a balanced / unbalanced converter is not required. Therefore, there is no factor that increases the manufacturing cost. As described above, according to the photoelectric field sensor according to the present invention, magnetic field information and electric field information can be separated and acquired at low cost and with high accuracy. Further, since there is no need for a shielded loop formed of a coaxial cable, the sensor can be downsized.

According to the photoelectric magnetic field sensor of the second aspect, in addition to the same configuration as the photoelectric magnetic field sensor of the first aspect,
The optical axes of the pair of electro-optic crystals are arranged in the same direction along the conductor pattern or in opposite directions along the conductor pattern. That is,
Specifically, by arranging the optical axis direction as described above, only magnetic field information or only electric field information can be reliably separated and obtained.

According to the third aspect of the present invention, in addition to the same configuration as the first and second aspects of the present invention, a pair of electro-optic crystals are formed of lithium niobate or lithium tantalate. It is configured to be performed. That is, by adopting lithium niobate or lithium tantalate as the electro-optic crystal, the operation and effect of claim 1 can be more reliably achieved.

According to a fourth aspect of the present invention, in addition to the same configuration as the first to third aspects, the conductive pattern is formed in a ring shape in a plane. ing. That is, since the conductor pattern is formed two-dimensionally in one plane, it is possible to reliably separate and acquire only the magnetic field information or the electric field information regardless of the direction of the electromagnetic field. .

According to the photoelectric field sensor according to the fifth aspect, in addition to the same configuration as the photoelectric field sensor according to the first to fourth aspects, it has a resistance connected in parallel with the electro-optic crystal in an electric circuit. It has a configuration. In other words, by connecting a resistor having variously selected resistance values in parallel with the electro-optic crystal in an electric circuit, it is possible to adjust the range of frequency characteristics of magnetic field information or electric field information that can be obtained.

According to the photoelectric field sensor according to the sixth aspect, in addition to the same configuration as the photoelectric field sensor according to the first to fifth aspects, a supporting portion is provided around the gap of the conductor pattern, and the supporting portion is provided between the supporting portions. By sandwiching the electro-optic crystal in the above, the electro-optic crystal is inserted into the gap. In other words, when an electro-optic crystal made of a material that cracks due to a rapid change in temperature is employed, the electro-optic crystal cannot be fixed by soldering, in which heat is applied. For this reason, in the present invention, by providing a support portion generally made of metal on the conductor pattern, the elasticity of the support portion is used to sandwich and fix the electro-optic crystal between the support portions. I made it.

According to the photoelectric field sensor according to the seventh aspect, in addition to the same configuration as the photoelectric field sensor according to the first to sixth aspects, a voltage having a magnitude capable of reversing the optical axis direction is applied to the electro-optic crystal. It has a configuration of having an optical axis reversing means for applying. That is, the direction of the optical axis of one of the pair of electro-optical crystals is different between the case where magnetic field information is extracted and the case where electric field information is extracted, so that the optical axis direction needs to be changed. .

On the other hand, the electro-optic crystal has a property that the direction of the optical axis is reversed when a large voltage is applied. In addition, by simply reversing the direction of the optical axis, magnetic field information and electric field information can be respectively extracted.

[0020] According to an eighth aspect of the present invention, there is provided a photoelectric field detecting device having a light source for generating light, a conductor pattern having a pair of gaps, and being annularly formed of a conductive material. It is characterized by having a pair of electro-optic crystals through which light from a light source can pass, and a light detecting member for detecting a state of light passing through each of the pair of electro-optic crystals.

According to the eighth aspect of the present invention, a pair of gaps are provided in the conductor pattern formed in a ring shape from a conductive material, and a pair of electro-optic crystals are provided in the pair of gaps. Has been inserted. Then, light from a light source that generates light passes through each of the pair of electro-optic crystals, and the state of the passed light is detected by the light detection member.

That is, in the photoelectric field detecting device according to the present embodiment, a pair of electro-optic crystals are inserted into a pair of gaps, respectively, as in the first aspect. Therefore, by allowing light such as laser light to pass through the pair of electro-optic crystals, only magnetic field information or only electric field information can be obtained separately.

Accordingly, since the photoelectric field detecting device according to the present invention uses light such as laser light,
Since there is no need for a coaxial cable and the metal portion is only a conductor pattern, high-precision measurement can be performed in the same manner as in claim 1 because disturbance in the surrounding electromagnetic field hardly occurs.

On the other hand, by adjusting the optical axis direction of the electro-optic crystal, magnetic field information and electric field information can be easily separated, and there is no need to have a hybrid circuit or a balanced / unbalanced converter. Manufacturing costs can be reduced. As described above, according to the photoelectric magnetic field detection device of the present invention, magnetic field information and electric field information can be separated and acquired at low cost and with high accuracy, as in the first embodiment.

According to the photoelectric magnetic field detecting device of the ninth to fourteenth aspects, in addition to the same structure as the photoelectric magnetic field detecting device of the eighth aspect, it has the same configuration as the second to seventh aspects, respectively. are doing. Therefore, these claims also have the same operational effects as those of the second to seventh aspects.

According to the photoelectric field detecting device of the fifteenth aspect, in addition to the same configuration as the photoelectric field detecting device of the eighth to fourteenth aspects, the state of light between the light source and the light detecting member can be changed. It has a configuration in which an adjustable optical member is arranged. That is, since the optical member adjusts the state of light and the light detection member detects the optimally adjusted state of light, the magnetic field information and the electric field information can be separated and acquired with higher accuracy.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of a photoelectric magnetic field sensor and a photoelectric magnetic field detecting device according to the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the photoelectric magnetic field detection device 10 according to the present embodiment transmits a sensor body 12, which is a photoelectric magnetic field sensor disposed in an electromagnetic field to be measured, and a laser beam L. It is composed of an optical system capable of receiving light. On the printed circuit board 14 serving as a support portion of the sensor main body 12, a conductor pattern 16 formed in a ring shape, for example, a square having a size of about 10 mm on a side, is formed of a conductive material such as a metal. It is provided in. The conductor pattern 16 is provided with a pair of gaps 18 that divide the conductor pattern 16 into two equal lengths.

As shown in FIG. 1, a first electro-optical element 21 is inserted and disposed at the left side of the pair of gaps 18 and the right side of the pair of gaps 18 is disposed. The second electro-optical element 22 is inserted and arranged at the location. That is, the pair of electro-optical elements 21
Reference numeral 22 is arranged at a position symmetric about the center of the conductor pattern 16. The first electro-optical element 21 and the second electro-optical element 22 disposed in the pair of gaps 18 are each formed of an electro-optic crystal. For example, lithium niobate (L
Crystals of iNbO ₃ ) have been used.

In this embodiment, the direction of the optical axis + Z of the electro-optic crystal indicated by the arrow in FIG.
The first electro-optical element 21 and the second electro-optical element 22 are arranged so as to be in the same direction along the clockwise direction of No. 6. As a result, if the arrangement is in the optical axis direction + Z indicated by the arrow in FIG. 1, the present embodiment is applied to the sensor main body 12 having the magnetic field extraction loop that can extract the magnetic field information.

A pair of chip resistors 24 are formed on the printed circuit board 14 so as to be connected in parallel with the first electro-optical element 21 and the second electro-optical element 22, respectively, in an electric circuit.
Inserted to adjust frequency characteristics. Therefore, the sensor main body 12 according to the present embodiment includes the printed circuit board 14,
The conductor pattern 16, the pair of electro-optical elements 21 and 22, and the pair of chip resistors 24 can be manufactured.

Next, the entire optical system of the photoelectric field detecting device 10 according to the present embodiment will be described with reference to FIG.
As shown in FIG. 2, the present embodiment has a laser light source 30 that generates a laser beam L, and a light emitting unit 32A provided at an end of an optical fiber 32 connected to the laser light source 30 is a laser light source. The laser light L sent from the light source 30 is emitted. On the other hand, a photo-detecting member that converts a change in light intensity into a change in current
An optical fiber 40 is connected to the detector 42, and a light receiving unit 40A provided at an end of the optical fiber 40 receives the laser light L. For this reason, the light receiving unit 40A
Passes through the optical fiber 40,
The photo detector 42 detects the state of the laser light L.

Further, between the light emitting section 32A and the light receiving section 40A, a polarizer 34 for polarizing the laser beam L, the first electro-optical element 21, the second electro-optical element 22, the wavelength A plate 36 and an analyzer 38 for converting a change in polarization state into a change in light intensity are arranged in a straight line. That is, the present embodiment is of a straight traveling system in which the laser light L travels straight.

Therefore, when the laser light source 30 is the laser light L
Is generated, the laser light L passes through the optical fiber 32 and is emitted from the light emitting section 32A.
Pass through the light receiving portion 40A of the optical fiber 40. Then, the photodetector 42 detects the state of the laser light L entering the optical fiber 40 from the light receiving section 40A.

On the other hand, the electromagnetic field information received by the sensor body 12 is a voltage generated in the gap 18 of the conductive pattern 16 which is a conductive loop. And the first electro-optical element 21 interconnected by the conductor pattern 16
And a change in the refractive index of the second electro-optical element 22.

Therefore, the photoelectric field detecting apparatus 10 according to the present embodiment is capable of controlling the change in the refractive index of the first electro-optical element 21 and the second electro-optical element 22 by using the first electro-optical element 21 and the second electro-optical element. The laser beam L is sequentially captured as a change in the polarization state of the laser light L sequentially incident on the laser beam 22. Then, by passing through the analyzer 38, the change in the polarization state is converted into a change in the intensity of the laser light L, and finally, the change is converted into a change in the amount of current by the photodetector 42.

As a result, electromagnetic field information around the sensor main body 12 can be obtained by displaying the detection result by a spectrum analyzer (not shown) connected to the photodetector 42. That is, as the optical system of the present embodiment, the laser light source 30 and the photodetector 42, and the optical fiber 3
2. It is composed of a polarizer 34, a wavelength plate 36, an analyzer 38, an optical fiber 40 and the like.

Next, the operation of the photoelectric field detecting device 10 according to the present embodiment will be described. According to the photoelectric field detecting device 10 according to the present embodiment, as shown in FIGS. 1 and 2, a pair of gaps is formed in a conductor pattern 16 formed of a conductive material in a plane on a printed circuit board 14. 1
8 are provided, and a pair of electro-optical elements 2 are provided in the pair of gaps 18 with the optical axis direction + Z adjusted.
1 and 22 are respectively inserted. A chip resistor 24 is arranged in parallel with each of the pair of electro-optical elements 21 and 22.

Further, not only does the laser light L from the laser light source 30 pass through the pair of electro-optical elements 21 and 22, respectively, but also a polarizer 34 disposed between the laser light source 30 and the photo detector 42, The photodetector 42 also detects the state of the laser beam L passing through the wave plate 36 and the analyzer 38 and passing therethrough.

That is, in the photoelectric field detecting device 10 according to the present embodiment, when the pair of electro-optical elements 21 and 22 are respectively inserted into the pair of gaps 18, they are in the same direction along the conductor pattern 16. In the optical axis direction + Z
Are arranged in an adjusted state. Therefore, by arranging the sensor main body 12 in the photoelectric magnetic field detecting device 10 at the position to be measured and passing the laser light L through the pair of electro-optical elements 21 and 22, only the magnetic field information is separated from the electric field information. And can be obtained.

Accordingly, the photoelectric field detecting device 10 according to the present embodiment uses the laser beam L, so that no coaxial cable is required. Disturbance is less likely to occur in the world.
Furthermore, since the laser beam L is used, there is no possibility that the function of the balance / unbalance conversion becomes insufficient, and there is no possibility that the electric signal receives noise during the transmission along the transmission path. That is, as a result, highly accurate measurement is possible.

On the other hand, since the magnetic field information and the electric field information can be easily separated by adjusting the optical axis direction + Z of the electro-optical elements 21 and 22, the connection with the hybrid circuit or the balanced / unbalanced converter is made. Since it becomes unnecessary, there is no longer a factor that increases the manufacturing cost. As described above, according to the photoelectric magnetic field detection device 10 according to the present embodiment, magnetic field information can be obtained separately from electric field information at low cost and with high accuracy.
Further, the sensor main body 12 includes electro-optical elements 21, 22,
Since the printed circuit board 14 and the conductor pattern 16 thereon, the chip resistor 24 and the like can be manufactured, there is no need for a shielded loop manufactured by a coaxial cable, so that the size of the sensor can be reduced.

On the other hand, in the present embodiment, the conductor pattern 1
Since 6 is formed two-dimensionally in one plane,
Regardless of the direction of the electromagnetic field, only the magnetic field information can be reliably separated and acquired from the electric field information. Further, in the present embodiment, since the chip resistor 24 having variously selected resistance values is arranged in parallel with the electro-optical elements 21 and 22, the range of the frequency characteristics of the magnetic field information or the electric field information that can be obtained can be adjusted. Become.

Further, in this embodiment, the laser light L is provided between the laser light source 30 and the photo detector 42.
Since the polarizer 34, the wavelength plate 36, and the analyzer 38 which are optical members capable of adjusting the state of the laser light L are arranged, these optical members adjust the state of the laser light L, and the optimally adjusted laser light L Is detected by the photodetector 42. For this reason, it becomes possible to separate the magnetic field information from the electric field information with higher accuracy.

Here, according to the present embodiment, in order to separate magnetic field information and electric field information, only the magnetic field information is used instead of the hybrid circuit required in the conventional double gap loop sensor. The fact that it can be obtained separately from the program will be described below. First, the electric field E _F occurring pair of electro-optical elements 21 and 22 by Faraday's law of electromagnetic induction, as shown in FIGS. 3 and 4, the conductor patterns 16
Are both clockwise along the circumferential direction.

Therefore, the sensor body 1 according to the present embodiment
2, the optical axis direction + Z of the electro-optical elements 21 and 22 is defined as a clockwise direction along the loop of the conductor pattern 16 and the pair of electro-optical elements 21 and 22 is used.
Are arranged, the electric field E _F is in the same direction as the optical axis direction + Z. However, although not shown, the electric field E _F
If is both in the counterclockwise direction, the electric field E _F are both the optical axis direction + Z and the opposite direction.

Next, the reason why only magnetic field information can be obtained will be specifically described below. If an external electric field shown in FIG. 3 is laterally, by the loop-shaped conductor pattern 16 is a vertically symmetrical structure, transverse induced in the electro-optical elements 21 and 22 by the external transverse electric field O _X indicated by an arrow field E _X are canceled as shown by an arrow indicated by a dotted line in FIG. 3, only the electric field E _F appears in the individual electro-optical elements 21 and 22. Therefore, it is understood that this embodiment functions as a magnetic field sensor that can acquire only magnetic field information separately from electric field information.

When the external electric field shown in FIG. 4 is in the vertical direction
Is the electric field E_FAnd the external vertical electric field O indicated by the arrow_ZBy electricity
Induced by the optical elements 21 and 22, indicated by dotted arrows
Vertical electric field E_ZAre superimposed on each other.
It is an electric field of the magneto-optical elements 21 and 22. In other words, the figure
4, if the clockwise direction is positive, the left first electric
Left electric field E generated in optical element 21_LAnd the second
Right electric field E generated in the magneto-optical element 22 _RRespectively E_L= E_F+ E_Z E_R= E_F-E_Z Is obtained by the following equation. Therefore, these can be expressed as
In addition to E_L+ E_R= 2E_F It becomes.

[0048] Then, the 2E _F which factors are the elimination of the vertical electric field E _Z by bisecting a pair of electro-optical element 2
The average electric field E _F responsible for external magnetic field information of 1, 22 will be obtained. For this reason, it can be understood that if the above calculation can be performed, in this case also, it functions as a magnetic field sensor that can acquire only magnetic field information separately from electric field information.

Next, as in the present embodiment, the pair of electro-optical elements 21 and 2 are arranged at positions symmetrical about the center of the conductor pattern 16 so that the optical axis direction + Z is both clockwise.
2 is inserted, and the laser light L is sequentially passed through the pair of electro-optical elements 21 and 22, respectively, so that only magnetic field information can be obtained separately from electric field information based on the above calculation.

[0050] For example, the vertical electric field E _Z induced in the electro-optical elements 21 and 22 by the external vertical electric field O _Z shown in FIG. 4 is a left-right both upward (however, in some cases the lateral both downward) . For this reason, in the first electro-optical element 21 on the left side, the optical axis direction + Z and the vertical electric field _EZ are in the same direction, but in the second electro-optical element 22 on the right side, the optical axis direction + Z.
Since Z and the vertical electric field E _Z is in the opposite direction to each other, when viewed across a pair of electro-optical elements 21 and 22, it is possible to cancel the electric field information by a vertical electric field E _Z as in the above operation.

[0051] Then, when passing through the electro-optical elements 21 and 22 of the laser beam L is dependent on the order, only the electric field E _F responsible for field information occurring in the clockwise direction on the conductor pattern 16 remains substantially since, the impact of the electric field E _F, the refractive index of the pair of electro-optical elements 21 and 22 is changed. As a result, the polarization state of the laser light L passing through the electro-optical elements 21 and 22 changes, so that in the present embodiment, only the magnetic field information can be obtained separately from the electric field information.

On the other hand, when there is an external electric field oblique to the side of the loop constituting the conductor pattern 16,
By decomposing the external electric field in the vertical direction and the horizontal direction, the same discussion as above can be obtained. The conductor pattern 16
Even if there is a component of the external electric field perpendicular to the surface of the printed circuit board 14 on which the conductive pattern is formed, since the conductor pattern is flat and the thickness can be ignored, there is no electric field generated in the gap portion.
From the above, it can be seen that in any case, the device functions as a magnetic field sensor that can acquire only magnetic field information separately from electric field information.

Next, the change in the polarization state of the laser light L generated in the electro-optical elements 21 and 22 based on the relationship between the direction of the electric field and the optical axis direction + Z will be described. The electric field generated in the gap 18 of the conductor pattern 16 causes a change in the refractive index of the electro-optical elements 21 and 22, and the electro-optical element 2
It can be recognized as a change in the polarization state of the laser light L passing through the first and second laser beams 22. The change in the polarization state is directly related to the phase difference between the components when the incident laser light L is decomposed in the optical axis direction + Z of the electro-optical elements 21 and 22 and the direction perpendicular thereto and proceeds through the crystal. Involved.

The phase difference ΔΦ can be expressed as ΔΦ = + αE, where α is a constant and the electric field is E, and the optical axis direction + Z and the direction of the electric field E are the same direction. When the optical axis direction + Z and the direction of the electric field E are opposite to each other, ΔΦ = −αE.

Therefore, the electric field E having the same magnitude is applied to the left and right electro-optical elements 21 and 22 in the optical axis direction +
If they exist in the same direction as Z, ΔΦ = + αE + αE = + 2αE, and the polarization state of the laser light L changes according to the change in the phase difference. On the other hand, the direction of the electric field E is the optical axis direction + Z
If the optical axis directions + Z of the left and right electro-optical elements 21 and 22 are both in the opposite directions, then ΔΦ = −αE−αE = −2αE. The state changes.

Further, although the sizes are equal to each other, if the optical axis direction + Z of one of the left and right electro-optical elements 21 and 22 and the direction of the electric field E are opposite to each other, ΔΦ = + αE−αE = 0, the phase difference is canceled, and the polarization state does not change. For example, the reason for the field information by a vertical electric field E _Z shown in FIG. 4 is canceled is thus a phase difference is canceled,
Change in the polarization state by the vertical electric field E _Z is because no.

Next, the sensor body 12 according to the present embodiment
Will be described with reference to FIGS. 5 and 6. A conductive adhesive S is applied to the upper and lower surfaces of the electro-optical elements 21 and 22 in FIG. 5 in advance, and an L-shaped copper is applied to an end portion 16A of the conductor pattern 16 which is a peripheral portion of the pair of gaps 18. The support members 17 which are support portions formed by the above are connected to each other by soldering. In this state, the pair of electro-optical elements 21 and 22 are pushed into the pair of gaps 18 along the direction of the arrow. At this time, at least the support member 17
The thickness of the portion facing the electro-optical elements 21 and 22 is 1
It is about 50 μm.

As a result, as shown in FIG. 6, the electro-optical elements 21 and 22 are formed between the pair of support members 17 formed and arranged in an L-shape on the pair of end portions 16A of the conductor pattern 16, respectively. The electro-optical elements 21 and 22 are respectively inserted into the pair of gaps 18 so as to be sandwiched and electrically connected to them, and are securely fixed. The reason for adopting such a fixing method is that when the electro-optical elements 21 and 22 made of lithium niobate or the like that cracks due to a rapid temperature change are employed, heat is applied to the electro-optical elements 21 and 22. This is because it cannot be fixed on the printed circuit board 14 by additional soldering.

As described above, in the present embodiment, the thickness 10
Conductor pattern 16 made of metal such as copper of about 30 μm
The support member 17 is disposed on the end 16A of the, and the elasticity of the support member 17 is used to sandwich the electro-optical elements 21 and 22 so as to be fixed therebetween. However, the thickness of the conductor pattern 16 was set to 150 μm without using the support member 17.
The conductor pattern 16 having a thickness of about 10 to 30 [mu] m may be used if the elasticity is sufficient and the electro-optical elements 21 and 22 are not loose. In the present embodiment, the conductive adhesive S is used when the electro-optical elements 21 and 22 are inserted into the pair of gaps 18 respectively. Instead of being applied, it may be simply sandwiched between the pair of ends 16A.

Next, a second embodiment of the photoelectric magnetic field sensor and the photoelectric magnetic field detecting device according to the present invention will be described with reference to FIG. The same members as those described in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. In the present embodiment, as shown in FIG. 7, the pair of electro-optical elements 21 and 22 are arranged so as to be inserted into the pair of gaps 18 formed in the conductor pattern 16, respectively. The pair of electro-optical elements 21 and 22 are fitted in a hole penetrating the printed board 14.

Further, a right-angle prism 52 is disposed at a position facing the printed circuit board 14, and the laser beam L passing through the first electro-optical element 21 is reflected by the right-angle prism 52 and is converted into a second electro-optical beam. It passes through the element 22. Therefore, the present embodiment operates in the same manner as the first embodiment.
2, the laser beam L is reflected so as to be a reciprocating system, so that the optical path of the laser beam L can be easily secured, and the photoelectric field sensor and the photoelectric field detecting device can be further downsized. Becomes possible.

Next, a third embodiment of the photoelectric magnetic field sensor and the photoelectric magnetic field detecting device according to the present invention will be described with reference to FIG. The same members as those described in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. In the present embodiment, a pair of electro-optical elements 21 and 22 are inserted at symmetrical positions as in the electric field extraction loop shown in FIG. 8, but at this time, the first electro-optical element 21 has an optical axis direction + Z The second electro-optical element 22 is inserted so that the optical axis direction + Z is counterclockwise. By sequentially passing the laser light L in this state, the following calculation for extracting only the electric field information can be realized.

That is, similar to the first embodiment, FIG.
If positive clockwise in left field E _L and generated in the first electro-optical element 21 on the left side, the right side electric field E _R occurring on the right side of the second electro-optical element _{22, E L = E F +} E Z E _R = E _F -E _Z , respectively.

For this reason, when these differences are obtained as in the following equation, E _L -E _R = 2E _Z. Then, this 2E which cause electric field E _F were eliminated
By bisecting _Z , a pair of electro-optical elements 21 and 22
So that the longitudinal electric field E _Z responsible for average external magnetic field information is obtained.

The result of this calculation will be specifically described below.
I will tell. That is, the external vertical electric field O_ZElectro-optical element 2
Vertical electric field E induced in 1, 22 _ZAre both upward
Therefore, the optical axis direction of the left and right electro-optical elements 21 and 22
+ Z and vertical electric field E_ZAre in the same direction. However, shown
No vertical electric field E_ZAre both downward, the vertical electric field E_Z
Are opposite to the optical axis direction + Z.

[0066] On the other hand, the law of electromagnetic induction Considering field E _F responsible for the magnetic field information generated in a pair of gaps 18 of the conductor pattern 16, into the first electro-optical element 21 in the optical axis direction + Z and the electric field E _F mutual in the same direction, but in another second electro-optical element 22 and the optical axis direction + Z and the electric field E _F is reversed direction to each other.

[0067] Therefore, if passing through the laser beam L each of the electro-optical elements 21 and 22 in this order, the remaining information by the vertical electric field E _Z, the electric field E _F responsible for field information occurring in the clockwise direction is canceled (Paragraph number 005
3-005). From the above, it can be seen that this embodiment functions as an electric field sensor that can acquire only electric field information separately from magnetic field information.

Next, a fourth embodiment of the photoelectric magnetic field sensor and the photoelectric magnetic field detecting device according to the present invention will be described with reference to FIGS.
It will be described based on. The same members as those described in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. It is generally known that an electro-optic crystal changes its signal due to a change in natural birefringence depending on the ambient temperature. However, an electro-optic crystal of the same size is connected in series with the optical axis direction + Z orthogonal to each other. It is also known that the two arrangements can cancel the change in the natural birefringence.

Therefore, in the present embodiment, as shown in FIG. 9, the left and right electro-optical elements 21 and 22 are moved in opposite directions to each other.
By arranging them at an angle of 5 °, the optical axis direction of each other + Z
Are relatively tilted at an angle of 90 °. That is,
With such an arrangement, temperature compensation can be realized when the laser beam L is transmitted. In the reciprocating system of the laser light L, as shown in FIG.
Will be inclined.

Next, a fifth embodiment of the photoelectric field sensor and the photoelectric field detecting apparatus according to the present invention will be described with reference to FIGS.
2 will be described. The same members as those described in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. In the present embodiment, as shown in FIG.
The laser beam L is passed through the pair of electro-optical elements 21 and 22 in parallel, and the wave plate 36 and the analyzer 38
These are arranged on a straight line so as to pass through. In this case, the laser light L generated from two laser light sources may be used, respectively, or the laser light L generated from one laser light source may be branched and used.

The laser beam L passing through the first electro-optical element 21 is finally incident on the photodetector 56 represented by PD2, and the laser beam L passing through the second electro-optical element 22 is finally transmitted. The pair of photodetectors 56 and 58 are arranged so as to be incident on the photodetector 58 represented by PD1. The pair of photo detectors 56 and 58 are connected to an amplifier 54 that can select a normal operation state and a differential operation state.

As described above, when the amplifier 54 is in the normal operation state, the signals due to the magnetic fields detected by the two photodetectors as shown in FIG.
The signal due to the electric field as shown in FIG. 12 (B) is canceled out, and the system becomes a magnetic field extraction system. On the other hand, when the amplifier 54 is in the differential operation state, the signal due to the magnetic field as shown in FIG. 12A is canceled out, but the signal due to the electric field as shown in FIG. It becomes.

In the above embodiment, the optical axis directions of the electro-optic crystal on one side of the magnetic field extraction loop and the electric field extraction loop are opposite to each other. However, when a large voltage is applied to the electro-optic crystal, Since the optical axis direction has the property of being reversed, adopting an optical axis reversing means that applies a voltage large enough to reverse the optical axis direction to the electro-optic crystal, applying a large voltage when necessary to reverse the optical axis direction By letting
The magnetic field information and the electric field information may be respectively extracted. Here, the optical axis reversing means may be, for example, a high-voltage power supply. By connecting this high-voltage power supply to both ends of the electro-optic crystal via a conducting wire, it is possible to easily apply a large voltage to the electro-optic crystal. Become.

Further, in the above embodiment, the conductor pattern is square, but the conductor pattern may be formed in another shape such as rectangle or circle, and the conductor pattern may be thin as in this embodiment. The material is not limited to a metallic conductive material, and may be a member such as a wire. On the other hand, in the above-described embodiment, lithium niobate (LiN
bO ₃ ), but lithium tantalate (LiTa)
Other electro-optic crystals such as O ₃ ) may be used.

[0075]

According to the present invention, it is possible to provide a photoelectric magnetic field sensor and a photoelectric magnetic field detecting device capable of separating and acquiring magnetic field information and electric field information with high accuracy at low cost.

[Brief description of the drawings]

FIG. 1 is a diagram of a sensor main body according to a first embodiment of the present invention, wherein (A) is a plan view and (B) is a side view.

FIG. 2 is an overall view showing a photoelectric field detecting device according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram illustrating extraction of a magnetic field by the sensor body according to the first embodiment of the present invention, in a case where an external lateral electric field is generated.

FIG. 4 is an explanatory diagram illustrating extraction of a magnetic field by the sensor main body according to the first embodiment of the present invention, in a case where an external vertical electric field is generated.

FIG. 5 is a perspective view for explaining assembly of the sensor main body according to the first embodiment of the present invention.

FIG. 6 is a cross-sectional view for explaining the assembly of the sensor main body according to the first embodiment of the present invention, and is a cross-sectional view showing a state where the electro-optical element is held between ends of a conductor pattern.

FIG. 7 is an explanatory diagram of a photoelectric field detecting device according to a second embodiment of the present invention.

FIG. 8 is a plan view of a sensor main body according to a third embodiment of the present invention.

FIG. 9 is a perspective explanatory view of another sensor main body according to a fourth embodiment of the present invention.

FIG. 10 is an explanatory plan view of a sensor main body according to a fourth embodiment of the present invention.

FIG. 11 is an explanatory diagram showing a photoelectric field detecting device according to a fifth embodiment of the present invention.

FIGS. 12A and 12B are diagrams showing signals based on a magnetic field and an electric field detected by two photodetectors, which are separately shown in FIGS.

FIG. 13 is an explanatory view of a main part of a first conventional example.

FIG. 14 is an explanatory diagram of a main part of a second conventional example.

FIG. 15 is an explanatory diagram of a main part of a third conventional example.

[Explanation of symbols]

10 Photoelectric field detector 12 Sensor body (photoelectric field sensor) 16 Conductor pattern 18 gap 21 1st electro-optic element (electro-optic crystal) 22 Second electro-optic element (electro-optic crystal) 24 chip resistors 30 Laser light source (light source) 42 Photo Detector (Light Detector)

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-6-160449 (JP, A) JP-A-64-75968 (JP, A) JP-A-58-99761 (JP, A) JP-A-2000-206154 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01R 33/032 G01R 29/08 G01R 15/24

Claims (15)

(57) [Claims] 1. A photoelectric device comprising: a conductive pattern having a pair of gaps and formed in a ring shape from a conductive material; and a pair of electro-optic crystals inserted into the pair of gaps, respectively. Magnetic field sensor. 2. The photoelectric device according to claim 1, wherein the optical axis directions of the pair of electro-optic crystals are arranged in the same direction along the conductor pattern or in opposite directions along the conductor pattern. Magnetic field sensor. 3. The photoelectric field sensor according to claim 1, wherein the pair of electro-optic crystals is formed of lithium niobate or lithium tantalate. 4. The photoelectric field sensor according to claim 1, wherein the conductor pattern is formed in an annular shape in a plane. 5. The photoelectric field sensor according to claim 1, further comprising a resistor connected in parallel with the electro-optic crystal in an electric circuit. 6. The electro-optic crystal according to claim 1, wherein a supporting portion is provided in a peripheral portion of the gap of the conductor pattern, and the electro-optic crystal is inserted into the gap by sandwiching the electro-optic crystal between the supporting portions. Item 6. The photoelectric magnetic field sensor according to any one of Items 5. 7. The photoelectric field sensor according to claim 1, further comprising an optical axis reversing means for applying a voltage having a magnitude capable of reversing an optical axis direction to the electro-optic crystal. . 8. A light source for generating light, a conductor pattern having a pair of gaps and formed in a ring shape from a conductive material, and light inserted from the pair of gaps and passed from the light source, respectively. An electro-optical magnetic field detection device comprising: a pair of electro-optic crystals to be obtained; and a light detection member for detecting a state of light passing through each of the pair of electro-optic crystals. 9. The photoelectric device according to claim 8, wherein the optical axis directions of the pair of electro-optic crystals are arranged in the same direction along the conductor pattern or in the opposite directions along the conductor pattern. Magnetic field detection device. 10. The photoelectric field detecting device according to claim 8, wherein the pair of electro-optical crystals are formed of lithium niobate or lithium tantalate. 11. The conductive pattern is formed in an annular shape in a plane.
The photoelectric field detecting device according to any one of the above. 12. The photoelectric field detecting device according to claim 8, further comprising a resistor connected in parallel with the electro-optic crystal in an electric circuit. 13. The electro-optic crystal according to claim 8, wherein a support portion is provided around a gap of the conductor pattern, and the electro-optic crystal is inserted into the gap by sandwiching the electro-optic crystal between the support portions. Item 13. The photoelectric field detection device according to any one of Items 12. 14. The photoelectric field detecting device according to claim 8, further comprising an optical axis reversing means for applying a voltage having a magnitude capable of reversing the direction of the optical axis to the electro-optic crystal. apparatus. 15. The photoelectric field detecting device according to claim 8, wherein an optical member capable of adjusting a state of light is disposed between the light source and the light detecting member. .