JP3702301B2 - Magnetic sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic sensor.
[0002]
[Prior art]
Magnetic sensors typified by semiconductor Hall elements are one of the most important sensors in the fields of household appliances and industrial machinery as control elements for brushless motors. Development is desired.
In general, the sensitivity of semiconductor magnetic sensors depends on the velocity of electrons in the semiconductor. Therefore, in recent years, a cold cathode solid-state vacuum device based on the principle of electric field emission has been used as a magnetic sensor as a breakthrough in improving the sensitivity of sensors. Attempts have been made.
FIG. 6 is a schematic diagram showing a configuration example of a conventional magnetic sensor.
In this conventional example, as shown in FIG. 6, an insulating or semi-insulating substrate 105, a comb-shaped field emission emitter electrode 101 provided on the substrate 105 for emitting electrons, and a substrate 105 are provided. A gate electrode 102 for controlling the number of electrons emitted from the field emission type emitter electrode 101, that is, an emitter current, and a substrate 105 provided on the substrate 105 for capturing the electrons emitted from the field emission type emitter electrode 101. It comprises anode electrodes 103a and 103b for collecting (see JP-A-6-308807).
[0003]
The magnetic sensor configured as described above is said to be usable even at high temperatures and in a radioactive environment, and can be expected to expand its application range.
The above-described magnetic sensor element fabrication is performed using a semiconductor process.
[0004]
[Problems to be solved by the invention]
Usually, the measurement of the magnitude of the magnetic field by the magnetic sensor as described above is performed based on the magnitude of the current value at the anode electrode, so that sufficient accuracy cannot be obtained unless the current value at the anode electrode is large. .
However, in the magnetic sensor configured as described above, since most of the electrons emitted from the field emission emitter electrode are incident on the gate electrode, the current flowing through the anode electrode is reduced and the magnitude of the external magnetic field is increased. There is a problem that it is difficult to measure the thickness.
In order to avoid this, it is conceivable to stabilize the internal magnetic field or the internal electric field, but in this case, there is a problem that the internal structure of the magnetic sensor becomes complicated and lacks practicality.
[0005]
Further, when the field emission type emitter electrode has a vertical structure, there is a problem that practicality is lacking because a sufficient anode current cannot be obtained with one element.
Furthermore, in magnetic field information, since only a maximum of two dimensions is obtained, there is a problem that the application range of the magnetic sensor is narrow.
The present invention has been made in view of the problems of the conventional techniques as described above, and can easily measure the magnitude of the magnetic field even when the current value at the anode electrode is small. An object of the present invention is to provide a magnetic sensor capable of obtaining dimensional magnetic field information.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention
A field emission emitter electrode for emitting electrons, a gate electrode for controlling the number of electrons emitted from the field emission emitter electrode, and at least collecting electrons emitted from the field emission emitter electrode An anode electrode divided into four, and a vacuum inside, and a package containing the field emission emitter electrode, the gate electrode and the anode electrode therein, and is radiated from the field emission emitter electrode In a magnetic field sensor for detecting an external magnetic field based on the number of electrons incident on the anode electrode among the electrons,
The electrons incident on the anode electrode are cross-shaped,
An equipotential shielding electrode made of a nonmagnetic conductive material is provided on the inner surface of the package .
[0007]
Further, a field emission type emitter electrode for emitting electrons, a gate electrode for controlling the number of electrons emitted from the field emission type emitter electrode, and at least four of the field emission type emitter electrodes are provided on the field emission type emitter electrode. A deflection electrode divided into at least four so as to face the deflection electrode, an anode electrode for collecting electrons emitted from the field emission emitter electrode, and a vacuum inside, A package that accommodates the field emission emitter electrode, the gate electrode, and the anode electrode inside, and externally based on the number of electrons incident on the anode electrode among electrons emitted from the field emission emitter electrode. In the magnetic field sensor that detects the magnetic field of
An equipotential shielding electrode made of a nonmagnetic conductive material is provided on the inner surface of the package.
The field emission type emitter electrode is provided in a plurality so as to form a cross shape. The cross shape is formed by intersecting columns of at least five field emission type emitter electrodes. Further, the field emission type emitter electrode, the gate electrode, and the deflection electrode are respectively arranged radially and symmetrically from the center of the cross-shaped electron beam . Also, the shielding electrode, characterized in that it also serves as the package.
[0009]
The anode electrode is formed by applying a conductive material to the inner surface of the package. The package is made of glass. Further, the conductive material is made of a fluorescent material, and the package is glass having translucency .
[0010]
On the other hand, the anode electrode is divided into at least four parts, and in each of the divided parts, electrons emitted from the field emission type emitter electrode are collected.
In this way, the center of the electrons emitted from the field emission type emitter electrode is clarified, and the irradiation position to the anode electrode at the center is also clarified by dividing the anode electrode. Even in a small case, it is possible to reliably detect displacement of the electron beam due to the magnetic field.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is a schematic diagram showing a first embodiment of the magnetic sensor of the present invention, where (a) is a perspective view, (b) is a top view of the substrate 5 shown in (a), and (c) is ( It is a figure for demonstrating the electron emission of the magnetic sensor shown to a).
In this embodiment, as shown in FIG. 1, a field emission emitter electrode 1 provided for emitting electrons, and a gate for controlling the number of electrons emitted from the field emission emitter electrode 1, that is, an emitter current. An electrode 2, an anode electrode 3 for collecting electrons emitted from the field emission emitter electrode 1, and deflection electrodes 4a, 4b for controlling the trajectory of the electrons emitted from the field emission emitter electrode 1. 4c and 4d, a field emission type emitter electrode 1, a gate electrode 2 and a substrate 5 that accommodates the deflection electrodes 4a, 4b, 4c, and 4d, and a package 8 that is an exterior that accommodates the anode electrode 3, the substrate 5 and wiring, Risk that the trajectory of electrons emitted from the field emission type emitter electrode 1 provided on the inner wall of the package 8 is bent regardless of the external magnetic field due to the electric field outside the package 8 The shielding electrode 7 for preventing, and an insulating member 6. The same potential is applied to the deflection electrodes 4a, 4b, 4c, and 4d, and the inner wall of the package 8 is applied to the shielding electrode 7 when the package 8 is a non-conductor. It is formed by applying a conductor to the surface, and the number of parts can be reduced, the ease of manufacturing can be improved, and the reliability can be improved.
[0012]
The deflection electrodes 4a, 4b, 4c, and 4d are equally divided into four portions of 90 ° around the field emission emitter electrode 1 from which electrons are emitted, and the anode electrode 3 is a deflection electrode. It is divided into four so as to face 4a, 4b, 4c and 4d.
Furthermore, the inside of the apparatus is kept in a vacuum.
All the electrodes and wirings described above are arranged radially and symmetrically from the field emission type emitter electrode 1 so that the orbit of electrons is not anisotropic. With this structure, the electric field applied to each electrode isotropically applied to the electrons, so that the anode electrode can be designed isotropically without considering the effect of the electric field. become.
[0013]
In the magnetic sensor configured as described above, the electron beam emitted from the field emission type emitter electrode 1 becomes a cross shape by the four divided deflection electrodes 4a, 4b, 4c, and 4d, and thereafter, The arrival position of the electron beam is detected by measuring the current due to the electron beam that reaches the anode electrode 3 divided into two.
The operation of the magnetic sensor configured as described above will be specifically described below.
2A and 2B are diagrams for explaining electron emission in the magnetic sensor shown in FIG. 1, wherein FIG. 2A is a diagram showing an electron arrival position when no magnetic field is applied, and FIG. 2B is a magnetic field in the Y direction. The figure which shows the arrival position of the electron at the time of applying By, (c) The figure which shows the arrival position of the electron at the time of applying the magnetic field Bx of X direction, (d) is the case where the magnetic field Bz of Z direction is applied It is a figure which shows the arrival position of an electron.
[0014]
First, a case where no external magnetic field is applied will be described.
The electrons emitted from the field emission type emitter electrode 1 diverge because they are not only components perpendicular to the substrate 5. At this time, the electrons emitted from the field emission type emitter electrode 1 are deflected by the deflection electrodes 4a, 4b, 4c, and 4d, and the grooves of the deflection electrodes 4a, 4b, 4c, and 4d as shown in FIG. Deflection electrodes 4a, 4b, 4c, centering on an intersection P (see FIG. 1) between XX ′ and groove YY ′, that is, an intersection P ′ of a perpendicular extending from the position of the field emission type emitter electrode 1 to the anode electrode 3 It reaches the anode electrode 3 vertically above the 4d groove XX ′ and the groove YY ′ in a cross shape.
Next, a case where an external magnetic field By in the Y direction is applied from the lower side to the upper side as shown in FIG. 2B will be described.
[0015]
When the external magnetic field By is applied from the bottom to the top of the page in the direction perpendicular to the groove XX ′ of the deflection electrodes 4a, 4b, 4c and 4d and horizontally to the groove YY ′, the electrons emitted from the field emission type emitter electrode 1 Receives a Lorentz force due to the interaction with the external magnetic field By, and the trajectory is bent to reach a position on the anode electrode 3 as indicated by a solid line in FIG. Here, the position shift at which the electrons reach increases as the external magnetic field By increases. Therefore, the intensity of the magnetic field applied from the outside can be detected by measuring the deviation from the electron arrival position when no external magnetic field is applied.
Next, a case where an external magnetic field Bx in the X direction is applied from the left side to the right side of the drawing as shown in FIG.
[0016]
When an external magnetic field Bx is applied horizontally from the left to the right of the paper in the groove XX ′ of the deflection electrodes 4a, 4b, 4c, 4d and perpendicularly to the groove YY ′, it is emitted from the field emission emitter electrode 1. The electrons are subjected to Lorentz force due to the interaction with the external magnetic field Bx, the trajectory is bent, and reach the position on the anode electrode 3 as indicated by the solid line in FIG.
Next, a case where an external magnetic field Bz in the Z direction is applied from the front side to the back side as shown in FIG.
When the external magnetic field Bz is applied from the front side to the back side of the paper, the electrons emitted from the field emission type emitter electrode 1 are subjected to Lorentz force due to the interaction with the external magnetic field Bz, and the trajectory is bent. A position as shown by a solid line in FIG.
[0017]
(Second Embodiment)
FIGS. 3A and 3B are schematic views for explaining a second embodiment of the magnetic sensor of the present invention, wherein FIG. 3A is a top view and FIG. 3B is a side view.
In this embodiment, as shown in FIG. 3, a field emission emitter electrode 11 provided for emitting electrons, and a gate for controlling the number of electrons emitted from the field emission emitter electrode 11, that is, an emitter current. An electrode 12, an anode electrode 13 for collecting electrons emitted from the field emission type emitter electrode 11, and a focusing electrode 14 for controlling the trajectory of electrons emitted from the field emission type emitter electrode 11. The field emission emitter electrode 11, the gate electrode 12, and the focusing electrode 14 are accommodated in a substrate (not shown), and the anode electrode 13, the substrate, and the wiring are provided in a package (not shown) serving as an exterior of the apparatus. Further, on the inner wall of the package, the trajectory of electrons emitted from the field emission type emitter electrode 11 is affected by the electric field outside the sensor and has no external magnetic field. Shielding electrode to prevent the risk of bent engagement (not shown) is provided.
[0018]
A plurality of field emission emitters 11 are arranged so as to form a single row XX ′ with a certain gap, and a plurality of field emission emitters 11 are formed so as to form a row YY ′ that intersects perpendicularly at the center of the row XX ′. It is arranged.
Further, the anode electrode 13 is divided into four parts with a portion facing the column XX ′ and the column YY ′ made of the field emission emitter 11 as a boundary.
In the magnetic sensor configured as described above, the current due to the electron beam emitted from the plurality of field emission emitter electrodes 11 formed in a cross shape and reaching the anode electrode 13 divided into four is measured. Thus, the arrival position of the electron beam is detected.
The operation of the magnetic sensor configured as described above will be specifically described below.
[0019]
4A and 4B are diagrams for explaining electron emission in the magnetic sensor shown in FIG. 3, wherein FIG. 4A is a diagram showing an electron arrival position when no magnetic field is applied, and FIG. 4B is a magnetic field in the Y direction. The figure which shows the arrival position of the electron at the time of applying By, (c) is a figure which shows the arrival position of the electron at the time of applying the magnetic field Bx of a X direction.
First, a case where no external magnetic field is applied will be described.
The electrons emitted from the field emission type emitter electrode 11 fly linearly in the vacuum and reach the anode electrode 13. Here, normally, the electrons emitted from the field emission type emitter electrode 11 diverge because they are not only components perpendicular to the substrate. However, since the convergence electrode 14 is provided, the electrons converge and are converged as shown in FIG. As shown in FIG. 5, the electric field is centered on the intersection of the column XX ′ and the column YY ′ of the field emission emitter electrode 11, that is, the intersection P ′ of the perpendicular extending from the position of the field emission emitter electrode 11 to the anode electrode 13. It reaches the anode electrode 13 vertically above the columns XX ′ and YY ′ of the emission emitter electrode 11 in a cross shape.
[0020]
Next, a case where an external magnetic field By in the Y direction is applied from the lower side to the upper side as shown in FIG. 4B will be described.
When the external magnetic field By is applied from the bottom to the top of the drawing in the direction perpendicular to the column XX ′ of the field emission emitter electrode 11 and horizontally to the column YY ′, electrons emitted from the field emission emitter electrode 11 are externally applied. The trajectory bends under the Lorentz force due to the interaction with the magnetic field By, and reaches a position on the anode electrode 13 as shown by the solid line in FIG. Here, the position shift at which the electrons reach increases as the external magnetic field By increases. Therefore, the intensity of the magnetic field applied from the outside can be detected by measuring the deviation from the electron arrival position when no external magnetic field is applied.
[0021]
Next, a case where an external magnetic field Bx in the X direction is applied from the left to the right as shown in FIG. 4C will be described.
When the external magnetic field Bx is applied from the left to the right of the page in the horizontal direction to the column XX ′ of the field emission emitter electrode 11 and perpendicular to the groove YY ′, the electrons emitted from the field emission emitter electrode 11 are In response to the Lorentz force due to the interaction with the external magnetic field Bx, the trajectory is bent and reaches a position on the anode electrode 13 as indicated by the solid line in FIG.
(Third embodiment)
FIG. 5 is a schematic view showing a third embodiment of the magnetic sensor of the present invention.
In this embodiment, the anode electrode 23 is formed as a part of the package 28 as compared with those shown in the first and second embodiments, and the other configurations are the same.
[0022]
As shown in FIG. 5, the anode electrode 23 is formed by dividing and applying a metal to the inner surface of the glass used as the package 28. As a result, the number of parts can be reduced, the ease of manufacturing can be improved, and the reliability can be improved.
Further, if a phosphor is applied on the anode electrode 23 formed on the inner surface of the package 28, light emission by electrons during operation can be confirmed from the outside, so that the normal operation of this element can be confirmed very easily. Will be able to.
Furthermore, if the glass used for the package 28 is formed by anodic bonding, the operating temperature range of the sensor is widened and the application range is widened.
In all the embodiments described above, the magnitude of the magnetic field measurement can be easily changed depending on the magnitude of the electric field applied to the anode electrode, and the distance between the emitter electrode and the anode electrode can be adjusted at the time of designing and manufacturing. May be.
[0023]
In addition, the width and resolution of the magnetic field measurement can be adjusted by the number and width of the anode electrodes.
Note that the anode electrode may be arranged in a grid, each electrode is connected to a scanning circuit, and the current is measured to measure the position where the cross-shaped electron beam reaches the anode electrode, thereby obtaining magnetic field information.
Further, in the above-described embodiment, a square substrate is used for the substrate of the field emission type emitter electrode and the substrate of the anode electrode. However, as described above, it is radial and symmetrical from the center of the field emission type emitter electrode. If it is, it may be polygonal or circular.
[0024]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
According to the first to fifth aspects of the present invention, electrons emitted from the field emission type emitter electrode are deflected into a cross-shaped electron beam and irradiated to the anode electrode divided into at least four parts. In each case, since the electrons emitted from the field emission type emitter electrode are collected, even when the current value at the anode electrode is small, it is possible to reliably detect the displacement of the electron beam due to the magnetic field.
Thereby, highly sensitive and highly dimensional magnetic field information can be obtained, and a highly versatile magnetic sensor can be provided.
[0025]
According to the sixth aspect of the present invention, since the equipotential shielding electrode made of a nonmagnetic conductive material is provided on the inner surface of the package, the electron trajectory is not bent regardless of the external magnetic field by the external electric field.
According to the seventh aspect of the present invention, since the shielding electrode also serves as a package, it is possible to reduce the number of parts, improve the ease of manufacturing, and improve the reliability. According to the eighth aspect of the present invention, since the anode electrode is formed by applying a conductive material to the inner surface of the package, the same effect as that of the seventh aspect can be obtained.
According to the ninth and tenth aspects of the present invention, since the conductive material is made of a phosphor and the package is made of a light-transmitting glass, light emitted by electrons during operation can be confirmed from the outside. The normal operation of the element can be confirmed very easily.
[0026]
Since the package is made of glass formed by anodic bonding, the operating temperature range of the sensor is widened and the application range is widened.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a first embodiment of a magnetic sensor according to the present invention, where (a) is a perspective view, (b) is a top view of a substrate shown in (a), and (c) is (a). It is a figure for demonstrating the electron emission of the magnetic sensor shown to).
2 is a diagram for explaining electron emission in the magnetic sensor shown in FIG. 1. FIG. 2 (a) is a diagram showing an electron arrival position when no magnetic field is applied, and FIG. The figure which shows the arrival position of the electron when the magnetic field By of Y direction is applied, (c) is the figure which shows the arrival position of the electron when the magnetic field Bx of X direction is applied, (d) is the magnetic field Bz of Z direction. It is a figure which shows the arrival position of the electron at the time of applying.
3A and 3B are schematic views for explaining a second embodiment of the magnetic sensor of the present invention, wherein FIG. 3A is a top view and FIG. 3B is a side view.
4A and 4B are diagrams for explaining electron emission in the magnetic sensor shown in FIG. 3, wherein FIG. 4A is a diagram showing an electron arrival position when no magnetic field is applied, and FIG. 4B is a magnetic field in the Y direction. The figure which shows the arrival position of the electron at the time of applying By, (c) is a figure which shows the arrival position of the electron at the time of applying the magnetic field Bx of a X direction.
FIG. 5 is a schematic view showing a third embodiment of the magnetic sensor of the present invention.
FIG. 6 is a schematic diagram showing a configuration example of a conventional magnetic sensor.
[Explanation of symbols]
1, 11 Field emission type emitter electrode 2, 12 Gate electrode 3, 13, 23 Anode electrode 4a, 4b, 4c, 4d Deflection electrode 5, 25 Substrate 6, 26 Insulator 7 Shield electrode 8, 28 Package 14 Converging electrode

Claims (9)

A field emission emitter electrode for emitting electrons, a gate electrode for controlling the number of electrons emitted from the field emission emitter electrode, and at least collecting electrons emitted from the field emission emitter electrode An anode electrode divided into four, and a vacuum inside, and a package containing the field emission emitter electrode, the gate electrode and the anode electrode therein, and is radiated from the field emission emitter electrode In a magnetic field sensor for detecting an external magnetic field based on the number of electrons incident on the anode electrode among the electrons,
The electrons incident on the anode electrode are cross-shaped,
A magnetic sensor comprising an equipotential shielding electrode made of a nonmagnetic conductive material on the inner surface of the package . A field emission emitter electrode for emitting electrons, a gate electrode for controlling the number of electrons emitted from the field emission emitter electrode, and provided on the field emission emitter electrode and divided into at least four A deflected electrode, an anode electrode for collecting electrons emitted from the field emission type emitter electrode , which is divided into at least four so as to face the deflected electrode, and a vacuum inside, and the electric field A radiation-type emitter electrode, a package containing the gate electrode and the anode electrode therein, and an external magnetic field based on the number of electrons incident on the anode electrode among electrons emitted from the field-emission emitter electrode In the magnetic field sensor that detects
A magnetic sensor comprising an equipotential shielding electrode made of a nonmagnetic conductive material on the inner surface of the package . The magnetic sensor according to claim 1,
The magnetic sensor according to claim 1, wherein a plurality of the field emission type emitter electrodes are provided so as to form a cross shape. The magnetic sensor according to claim 3.
2. The magnetic sensor according to claim 1, wherein the cross shape is formed by intersecting columns of at least five field emission type emitter electrodes. The magnetic sensor according to claim 1 , wherein:
The magnetic field emission type emitter electrode, the gate electrode, and the deflection electrode are respectively arranged radially and symmetrically from the center of the cross-shaped electron beam. The magnetic sensor according to any one of claims 1 to 5 ,
The magnetic sensor, wherein the shield electrode also serves as the package. The magnetic sensor according to any one of claims 1 to 3,
The magnetic sensor according to claim 1, wherein the anode electrode is formed by applying a conductive material to the inner surface of the package. The magnetic sensor according to claim 7 ,
The magnetic sensor is characterized in that the package is made of glass. The magnetic sensor according to claim 7 or 8 ,
The magnetic sensor according to claim 1, wherein the conductive material is made of a fluorescent material, and the package is made of glass having translucency.

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