JP6553308B2 - Vibration sensor - Google Patents

Description

  The present invention relates to a vibration sensor.

  There is known a vibration sensor that detects the presence or absence of vibration using electrical contact between a movable electrode capable of moving due to external force caused by vibration or the like and a fixed electrode positioned close to the movable electrode. The vibration sensor is also used to detect inclination and the like. Further, in recent years, a configuration has also been proposed which suppresses the breakage of the vibration sensor due to the difference in the thermal expansion coefficient between the member fixing the fixed electrode and the fixed electrode.

  In recent years, with regard to vibration sensors, there has been a demand for improvement of operation characteristics such as that even smaller vibrations can be effectively detected.

  A vibration sensor according to an embodiment of the present invention includes a substrate having an upper surface including a central portion and a frame-like outer peripheral portion surrounding the central portion, the vibration sensor being located at the outer peripheral portion of the upper surface and surrounding the central portion in plan view And a container portion including a lid closing the upper opening of the frame, a first electrode located at the central portion of the upper surface, and a flat surface located at the outer periphery of the upper surface A planar electrode portion including a second electrode separated from the first electrode in a visual manner and surrounding the first electrode; and a spherical electrode positioned in the container portion and in contact with the planar electrode portion; A granular conductor is provided between the planar electrode portion and the spherical electrode.

  According to the present invention, it is possible to provide a vibration sensor that is effective for improving the operating characteristics, for example, even small vibrations can be detected.

It is a perspective view showing the appearance of the vibration sensor concerning this embodiment. It is a perspective view which shows the state which removed the cover body from the vibration sensor which concerns on this embodiment. (A) is a side view which expands and shows a part of vibration sensor which concerns on this embodiment, (b) is sectional drawing which expands and shows a part of (a). It is a side view of the vibration sensor shown in FIG. (A) is a top view of the vibration sensor shown in FIG. 1, (b) is a bottom view. It is a perspective view which shows the cross section of the vibration sensor in alignment with XX of FIG. It is sectional drawing of the vibration sensor shown in FIG. It is a perspective view which decomposes | disassembles and shows the vibration sensor shown in FIG. (A) And (b) is a top view which decomposes | disassembles and shows the vibration sensor shown in FIG. (A) is the perspective view which looked at the package contained in the vibration sensor shown in FIG. 1 from the upper side, (b) is the perspective view seen from the lower side.

  Hereinafter, embodiments of a vibration sensor according to the present invention will be described with reference to the attached drawings. In addition, this invention shall not be limited to the following embodiment. Further, the distinction between the upper and lower sides in the following embodiments is for convenience, and does not limit the upper and lower sides when the vibration sensor is actually used.

<Schematic configuration of vibration sensor>
FIG. 1 is an external perspective view of the vibration sensor according to the present embodiment, showing a state where a lid is attached. FIG. 2 is an external perspective view of the vibration sensor according to the present embodiment, and shows a state where the inside can be seen by removing the lid. 3A is an enlarged side view showing a part of the vibration sensor according to the present embodiment, and FIG. 3B is a sectional view showing an enlarged part of FIG. . FIG. 4 is a side view of the vibration sensor shown in FIG. 5A is a top view of the vibration sensor shown in FIG. 1, and FIG. 5B is a bottom view. 6 is an external perspective view showing a cross section of the vibration sensor taken along the line XX of FIG. FIG. 7 is a cross-sectional view of the vibration sensor shown in FIG. FIG. 8 is an exploded perspective view showing the vibration sensor shown in FIG. FIGS. 9A and 9B are exploded plan views of the vibration sensor shown in FIG. FIG. 10A is a perspective view of a package included in the vibration sensor shown in FIG. 1 as viewed from above, and FIG. 10B is a perspective view as viewed from below.

  The vibration sensor is incorporated in various devices such as transportation devices such as automobiles, home appliances or electronic devices, and is for detecting vibration of these devices. The vibration sensor can also detect inclination or the like of these various devices. Examples of home appliances or electronic devices are digital cameras, mobile phones, smart phones and the like. The vibration sensor can detect the vibrations of various devices as described above based on a change in the conductive state between a planar electrode portion and a spherical electrode, which will be described later.

  The vibration sensor 9 according to the present embodiment includes a container part 1, a planar electrode part 2 provided in the container part 1, a spherical electrode 3 located in the container part 1, a planar electrode part 2 and a spherical electrode 3. And a granular conductor 4 positioned between the two. The container portion 1 includes a substrate 11 having an upper surface including a central portion and a frame-shaped outer peripheral portion surrounding the central portion, and a frame body 12 positioned on the outer peripheral portion of the upper surface of the substrate 11 and surrounding the central portion in plan view. And a lid 13 for closing the upper opening of the frame 12. The planar electrode portion 2 is located at the center of the upper surface of the substrate 11 and the outer peripheral portion of the upper surface, and surrounds the first electrode 21 apart from the first electrode 21 in plan view. And a second electrode 22. The spherical electrode 3 is located in the container 1, that is, in a storage container (not indicated as a storage container) surrounded by the upper surface of the substrate 11, the inner surface of the frame 12 and the lid 13. The spherical electrode 3 is in contact with at least one of the planar electrode portion 2 exposed in the storage container, that is, the first electrode 21 and the second electrode 22. The granular conductor 4 is disposed in the storage container so as to be located at least between the planar electrode portion 2 and the spherical electrode 3.

  The central portion of the upper surface of the substrate 11 is, for example, a rectangular or circular region surrounding the center and adjacent to the center of the upper surface of the substrate 11 having a rectangular shape. For example, the outer peripheral portion of the upper surface of the substrate 11 is a portion outside the central portion described above. The outer peripheral portion has, for example, an inner edge in contact with the outer periphery of the central portion and an outer edge located on the outer periphery of the upper surface of the substrate 11.

  The substrate 11 is an insulating substrate, and is made of, for example, a ceramic material such as alumina, mullite or aluminum nitride, or a glass ceramic material. Alternatively, it is composed of a composite material in which a plurality of materials among these materials are mixed. The substrate 11 has a rectangular outer shape in plan view, and the length of one side is set to 1 mm or more and 10 mm or less. The thickness of the substrate 11 is set to 0.5 mm or more and 3 mm or less. The thermal conductivity of the substrate 11 is set to 14 W / m · K or more and 200 W / m · K or less. The thermal expansion coefficient of the substrate 11 is set to 4 ppm / K or more and 8 ppm / K or less.

  The substrate 11 is manufactured by, for example, a ceramic green sheet lamination method, and a plurality of insulating layers (without reference numerals) may be laminated one on the other. Each of the plurality of green sheets serves as an insulating layer. In the example of this embodiment, the individual insulating layers (lines indicating the interface between the insulating layers) are not shown. Details of the method of manufacturing the substrate 11 will be described later.

  The frame 12 is provided on the substrate 11 so as to surround the second electrode 22. The outer periphery of the frame 12 is provided along the outer peripheral edge of the substrate 11. The frame 12 seals the second electrode 22 and the spherical electrode 3. The frame 12 is made of an insulating material, for example, a ceramic material such as alumina, mullite or aluminum nitride, or a glass ceramic material. Alternatively, it is composed of a composite material in which a plurality of materials among these materials are mixed. The frame 12 has a rectangular outer edge in plan view, and the length of one side of the outer edge is set to 1 mm or more and 10 mm or less. The thickness in the vertical direction of the frame 12 is set to 0.6 mm or more and 6 mm or less. Further, the thermal conductivity of the frame 12 is set to 14 W / m · K or more and 200 W / m · K or less.

  Further, in the example of this embodiment, the substrate 11 has a recess 14 in the central portion of the upper surface thereof. The recess 14 is sized to receive the plate-like first electrode 21 described later. The recess 14 is provided in a central portion of the upper surface of the substrate 11. The recess 14 is circular in plan view, and has a diameter of, for example, 0.5 mm or more and 5 mm or less. For example, the depth in the vertical direction of the recess 14 is set to 0.3 mm or more and 2.5 mm or less.

  In this embodiment, the first electrode 21 included in the planar electrode portion 2 is formed of a disk-shaped conductive plate (hereinafter, the first electrode 21 may be referred to as a conductive plate). The second electrode 22 is formed of a cylindrical conductive plate. The cylindrical conductive plate is disposed on the outer peripheral portion of the upper surface of the substrate 11 to constitute the second electrode 22. The disc-shaped conductive plate and the cylindrical conductive plate are separated from each other and are not in direct contact with each other.

  The first electrode 21 may be electrically connected to the spherical electrode 3. This electrical connection is made by direct contact between the lower end portion of the spherical electrode 3 and the upper surface of the first electrode 21. When the first electrode 21 is a circular conductive plate (i.e., a disk) as described above, for example, a metal material such as tungsten, molybdenum, nickel, cobalt, iron, copper, silver, gold, or aluminum It is produced by. Also, the conductive plate may be made of an alloy containing these metal materials. Further, the conductive plate may be made of a composite material obtained by mixing a plurality of materials among metal materials including these alloy materials, or a composite layer of those materials.

  A specific example of the first electrode 21 is as follows. The thermal expansion coefficient of the first electrode 21 is set to 3 ppm / K or more and 28 ppm / K or less. The diameter of the first electrode 21 is 0.2 mm or more and 3 mm or less, and the thickness in the vertical direction is set to 0.3 mm or more and 2.5 mm or less.

  In addition, the first electrode 21 may have a curved upper surface or the like (not shown). In this case, for example, the thickness of the central portion of the first electrode 21 in a plan view is about 0.5 to 2.5 mm, and the outer peripheral portion is set to be positioned 0.3 to 2.3 mm below that. In this case, the upper surface of the first electrode 21 is entirely curved. In the above example, the thickness of the first electrode 21 may be set so that the curvature radius of the upper surface of the first electrode 21 is a curved surface of about 0.3 to 15 mm. The first electrode 21 is connected to the bottom of the recess 14 via a brazing material.

  The first electrode 21 is a disk having a predetermined thickness, thereby efficiently absorbing heat in the spherical electrode 3, the recess 14, or the space inside the vibration sensor 9 (portion corresponding to the storage container described above). can do. Thereby, heat can be easily dissipated to the outside of the vibration sensor 9 from the first electrode 21 through the substrate 11. Heat is easily accumulated in the space inside the vibration sensor 9 including the recess 14. The heat is applied, for example, to the process of manufacturing the vibration sensor 9 or the heat applied when mounting it on the external mounting substrate via solder, the heat applied to the environmental test and the reliability test of the vibration sensor 9, or the vibration sensor 9. Heat generated when the Therefore, by providing the first electrode 21 having the thickness as described above, the heat in the space inside the vibration sensor 9 including the recess 14 is transferred to the outside of the vibration sensor 9 via the first electrode 21 and the substrate 11. Easy to dissipate. The thickness of the first electrode 21 may easily absorb heat from the inside of the spherical electrode 3 or the vibration sensor 9. That is, the thickness of the first electrode 21 may be set to a half or more of the thickness of the substrate 11 and a diameter that is half or more of the diameter of the spherical electrode 3.

  In the state where the first electrode 21 is housed in the recess 14, a gap sp <b> 1 is provided between the side surface of the first electrode 21 and the inner wall surface of the recess 14. The gap sp1 is set so that the side surface of the first electrode 21 does not contact the inner wall surface of the recess 14 even if the first electrode 21 undergoes thermal expansion. If the first electrode 21 is set in the recess 14 with no gap, there is a fear as follows. That is, the first electrode 21 undergoes thermal expansion, and thermal stress is applied from the first electrode 21 to the inner wall surface of the recess 14, which may destroy the substrate 11. Therefore, by providing the gap sp1 between the side surface of the first electrode 21 and the inner wall surface of the recess 14, the thermal stress from the first electrode 21 on the inner wall surface of the recess 14 can be effectively reduced.

  In this embodiment, the first electrode 21 is insulated from the first metallized layer 6 a disposed on the outer peripheral portion of the upper surface of the substrate 11.

  In the container portion 1, another metallized layer may be arranged separately from the first metallized layer 6 a on either or both of the substrate 11 and the frame 12. For example, the second metallized layer 6 b is provided on the bottom surface of the recess 14 such that the first electrode 21 is bonded via a bonding material such as silver solder. The second metallized layer 6 b can function as, for example, a base metal layer for bonding the first electrode 21.

  The substrate 11 may be provided with an inner layer wiring conductor (not shown) that is electrically connected to the second metallized layer 6b. Further, the substrate 11 may be provided with a first through conductor (not shown) penetrating from the upper surface to the lower surface. The first through conductor is electrically insulated from the first metallized layer 6a and is electrically connected to the second metallized layer 6b and the inner wiring conductor. The first through conductor as described above functions as a conductive path for electrically leading the first metallized layer 6a and the inner layer wiring conductor to the outer surface of the container portion 1 and for electrically connecting to the external electric circuit. Can do. In such a case, the first through conductor is electrically connected to the first electrode 21 through the inner layer wiring conductor and the second metallized layer 6 b.

  Further, even if the first through conductor is provided at the center position of the recess 14 and is directly connected to the second metallized layer 6 b so as to penetrate the bottom surface of the substrate 11 from the bottom of the recess 14 without providing the inner layer wiring conductor. Good. Thereby, the heat from the first electrode 21 is transmitted to the first through conductor via the second metallized layer 6 b. This heat is conducted downward of the first through conductor. Therefore, the heat in the recess 14 can be transmitted (radiated) to the outside.

  In addition, the first through conductor may be provided in each layer from the upper surface to the lower surface of the substrate 11 on which the plurality of insulating layers as described above are stacked, and the inner layer wiring and the second metalization provided in each layer of the substrate 11 It may be electrically connected to layer 6b. The first through conductor is a cylindrical via conductor. The first through conductor is made of, for example, a metal material such as tungsten, molybdenum, manganese, nickel, copper, silver, gold or aluminum. The first through conductor may be made of an alloy material including those metal materials. Further, the first through conductor may be made of a composite material in which a plurality of materials among these metal materials are mixed, or a composite layer of those materials. The first through conductor has a diameter of 0.1 mm or more and 1 mm or less. In addition, the length of the first through conductor in the vertical direction is set to 0.2 mm or more and 2.7 mm or less.

  As described above, the first metallized layer 6a formed on the upper surface of the substrate 11 surrounds the recess 14 in plan view. A portion of the upper surface of the first metallized layer 6a and the lower end of the second electrode 22 are bonded to each other directly or through a conductive connecting material (not shown), and the first metallized layer 6a and the second electrode 22 are formed. And are electrically connected to each other.

  In the example of this embodiment, the first metallized layer 6 a has a frame shape and is formed except for the periphery of the recess 14. The first metallized layer 6a in this embodiment has a first peripheral edge (outer peripheral edge) opposite to the concave portion 14 and a second peripheral edge (inner peripheral edge) on the concave portion 14 side. The second peripheral edge of the first metallized layer 6 a is closer to the outer periphery of the upper surface of the substrate 11 than the edge of the recess 14. Further, the first metallized layer 6 a is not formed on the inner wall surface of the recess 14.

  In addition, the first metallized layer 6a may be partially provided with an insulating portion (so-called clearance) (not shown), and the upper surface of the first through conductor may be disposed in the insulating portion. That is, the first metallized layer 6a is not limited to a frame shape, and may be a discontinuous (divided into a plurality of) frame shapes in part of the first and second peripheral edges in the length direction. Further, the first metallized layer 6a may have a shape in which at least one of the first peripheral edge and the second peripheral edge has unevenness.

  In this embodiment, the first metallized layer 6a has a frame-like or annular pattern in plan view. In the vibration sensor 9 of the embodiment, the first peripheral edge of the first metallization layer 6a having a frame shape or the like has a quadrangular shape or a square shape in which corners are formed in an arc shape, for example, as shown in FIG. The first peripheral edge of the first metallization layer 6 a having a rectangular shape or the like is located between the substrate 11 and the frame body 12. In other words, the first metallized layer 6a has a first peripheral edge (outer peripheral edge) sandwiched between the substrate 11 and the frame body 12 and is not exposed to the outside. Furthermore, in other words, the first peripheral edge of the first metallized layer 6 a is located inside the outer surface of the frame 12.

  In this case, since the first peripheral portion (peripheral portion) of the first metallized layer 6a is sandwiched between the substrate 11 and the frame 12, stress caused by the contact between the second electrode 22 and the spherical electrode 3 is concentrated. Bonding between the outer peripheral portion of the easy-to-use metallized layer and the substrate 11 is effectively improved. Therefore, even if stress is generated repeatedly in the first metallized layer 6a, for example, the possibility of occurrence of mechanical failure such as peeling between the first metallized layer 6a and the substrate 11 can be reduced. Also, the following effects can be obtained. That is, stress is generated along with the difference in thermal expansion coefficient (linear expansion coefficient etc.) between the substrate 11 and the frame 12 sandwiching the outer peripheral portion of the first metallized layer 6a and the first metallized layer 6a. The possibility of peeling and the like of the first metallized layer 6a caused by the stress can be similarly reduced.

  Further, in this case, the first peripheral edge of the first metallized layer 6 a is not exposed to the outer side surface of the vibration sensor 9. Therefore, the possibility of electrical shorting with an external metal member (such as a housing of an electronic device) disposed outside the vibration sensor 9 can be reduced.

  When the first metallized layer 6a has a frame shape cut as described above, the second electrode 22 is connected to each of the first metallized layer 6a. That is, one second electrode 22 is connected across a plurality of cut frame-shaped first metallization layers 6a. Moreover, in this case, it has a side edge part (not shown) which connects between the ends of the first peripheral edge and the second peripheral edge. A portion close to the first peripheral edge among the side edge portions may be set so as to be positioned between the substrate 11 and the frame body 12 like the first peripheral edge. Also at this time, the inclination of the electronic device can be detected by the electrical connection by the contact between the first electrode 21 and the frame-shaped conductive member via the spherical electrode 3.

  The first metallized layer 6a and the second metallized layer 6b are made of a metal material such as tungsten, molybdenum, nickel, copper, silver, gold, or aluminum. The first metallized layer 6a and the second metallized layer 6b may be made of an alloy material of these metal materials. The first metallized layer 6a and the second metallized layer 6b are composed of a composite material obtained by mixing a plurality of materials including the above metal materials, or a composite layer of these materials. The first metallized layer 6a and the second metallized layer 6b may be made of different types of metal materials, and may be different in thickness. The first metallized layer 6a and the second metallized layer 6b may be provided with a plating layer such as nickel and gold on the surface.

  In addition, the third metallized layer 6c may be provided on the upper surface of the frame 12 as another example of the other metallized layers described above. The third metallized layer 6c is electrically joined to the lid 13 by joining the lid 13 via, for example, gold-tin solder. The frame 12 is provided with an in-frame through conductor (not shown) as a wiring conductor which penetrates the lower surface from the upper surface and is electrically connected to the lid 13 through the third metallized layer 6c. . The in-frame penetrating conductor extends from the upper surface of the frame 12 through the inside of the frame 12 to the lower surface of the frame 12. Further, the lower surface of the in-frame through conductor is electrically connected to the upper surface of the first through conductor. Thus, the substrate 11 and the frame body 12 are electrically connected from the upper surface of the frame body 12 to the lower surface of the substrate 11 by the first through conductor and the in-frame through conductor. The in-frame through conductor is made of a conductive material, for example, a metal material such as tungsten, molybdenum, manganese, nickel, copper, silver, gold, or aluminum. Also, the in-frame through conductor may be made of an alloy material of those. Alternatively, the in-frame through conductor may be composed of a composite material obtained by mixing a plurality of materials among these materials, or a composite layer of these materials. The thermal expansion coefficient of the frame 12 is set to 4 ppm / K or more and 8 ppm / K or less.

  The second electrode 22 is provided on the first metallized layer 6 a as shown in FIGS. 6 and 7. The lower surface of the second electrode 22 is connected to the first metallized layer 6 a via a brazing material (not shown). The second electrode 22 is formed of a cylindrical conductive plate. As shown in FIG. 9, the second electrode 22 is provided so that the center of the first electrode 21 coincides with the center of the region surrounded by the second electrode 22 in plan view. The second electrode 22 is made of, for example, a metal material such as tungsten, molybdenum, iron, nickel, cobalt, copper, silver, gold or aluminum. Further, the second electrode 22 may be made of an alloy material of those. The second electrode 22 may be made of a composite material in which a plurality of materials are mixed. The thermal expansion coefficient of the second electrode 22 is set to 3 ppm / K or more and 28 ppm / K or less.

  The second electrode 22 has a size that fits in the frame 12, and for example, has a cylindrical shape with an outer diameter of 0.45 mm or more and 7.5 mm or less and an inner diameter of 0.3 mm or more and 6 mm or less. In addition, the length of the second electrode 22 in the vertical direction is set to 0.4 mm or more and 4 mm or less.

  The spherical electrode 3 fits inside the second electrode 22. The spherical electrode 3 is located near the center of the region surrounded by the second electrode 22 as shown in FIGS. 6 and 7. In this case, an insulating space sp2 is provided between the inner wall surface of the second electrode 22 and the surface of the spherical electrode 3. The size of the insulating space sp2 changes as the spherical electrode 3 moves on the first electrode 21. In the insulating space sp2, in the planar direction along the upper surface of the substrate 11, the maximum distance between the inner surface of the second electrode 22 and the surface of the spherical electrode 3 is set to 0.05 mm or more and 2 mm or less. And it moves according to the inclination resulting from the vibration etc. of the electronic device in which the vibration sensor 9 is mounted. When the electronic device is tilted, the spherical electrode 3 moves inside the second electrode 22 and hits the inside of the second electrode 22. As a result, the electrical conduction between the spherical electrode 3 and the second electrode 22 changes. As a result, the vibration sensor 9 can detect that the electronic device is inclined.

  The spherical electrode 3 is provided on the substrate 11 in a region surrounded by the second electrode 22 in contact with the first electrode 21. The spherical electrode 3 can move on the first electrode 21 according to the vibration or inclination of the vibration sensor 9 or the like. The spherical electrode 3 can move freely in the area surrounded by the second electrode 22. The movement of the spherical electrode 3 on the first electrode 21 is by rolling or sliding.

  When the vibration sensor 9 falls in the lateral direction (for example, when the left and right direction in FIG. 7 becomes the vertical direction), the spherical electrode 3 is the surface of the second electrode 22 (the upper surface in the collapsed state) ), While being connected to the second electrode 22. That is, the spherical electrode 3 is in contact with at least one of the first electrode 21 and the second electrode 22 and in contact with the planar electrode portion 2.

  At least the exposed surface of the spherical electrode 3 is made of, for example, a metal material such as tungsten, molybdenum, iron, nickel, cobalt, chromium, copper, silver, gold or aluminum. The spherical electrodes 3 may be made entirely of those metal materials. In addition, the spherical electrode 3 may be made of an alloy material of those metal materials. In addition, the spherical electrode 3 may be made of a composite material in which a plurality of materials including those metal materials are mixed. The spherical electrode 3 has a size that fits in the area surrounded by the second electrode 22 and has a diameter of 0.2 mm or more and 5 mm or less. The spherical electrode 3 may be one in which the layer of the above-mentioned metal material is disposed on the exposed surface of a spherical main body made of a resin material. The layer of the metal material can be formed, for example, in the form of a plated layer or a metallized layer.

  A plating layer such as nickel and gold may be provided on the surface of the spherical electrode 3 and the planar electrode portion 2 exposed in the storage container. Thereby, oxidation of the exposed surfaces of the spherical electrode 3 and the surface electrode portion 2 in the storage container is suppressed, and the long-term reliability as the vibration sensor 9 is improved.

  As in the example shown in FIG. 3, the granular conductor 4 is located between the planar electrode portion 2 and the spherical electrode 3. The granular conductor 4 has a function of facilitating the movement of the spherical electrode 3 as described above. In FIG. 3, the spherical electrode 3 moves in the direction of the arrow. When the granular conductor 4 is located between the planar electrode portion 2 and the spherical electrode 3, the spherical electrode 3 moves along the surface of the planar electrode portion 2 such as the upper surface of the first electrode 21. In addition, the possibility of contact between plating layers such as gold is reduced. That is, the possibility of an increase in frictional resistance due to contact between relatively soft gold plating layers is reduced. In other words, the interposition of the granular conductor 4 reduces the resistance of sliding or rolling between the spherical electrode 3 and the planar electrode portion 2, and the spherical electrode 3 can move more easily than in the past.

  The granular conductor 4 is preferably made of a material that has a smaller coefficient of friction than gold and is less likely to be deformed in order to obtain the above-described effects. Such materials include, for example, metal materials such as magnesium and tungsten, or carbon. The particulate carbon is, for example, an industrial carbon composite material.

  The granular conductor 4 is a plurality of conductor particles, and the size of each conductor particle is, for example, about 3 to 30 μm. Further, the shape of each conductor particle is not limited to the one having a circular cross section as in the example shown in FIG. 3, and may be a spherical or ellipsoidal shape having an uneven portion, or may be indeterminate shape. In order to facilitate the movement of the spherical electrode 3 along the surface of the planar electrode portion 2, it is advantageous that the granular conductor 4 has a spherical surface or the like with a smooth surface. Further, the plurality of granular conductors 4 may have the same particle diameter as each other, or may have a variation in particle diameter.

  The particle diameter of the granular conductor 4 is, for example, about 10 μm or less as an average particle diameter. The particle diameter in this case is the diameter when the granular conductor 4 is spherical or spherical and has a shape with irregularities on the surface. The particle diameter can be adjusted by performing classification on the granular conductor 4 (powdery one) using various devices for classification. Moreover, after sampling the granular conductor 4 from the actual vibration sensor 9, it can measure by the method of directly observing and measuring with a microscope etc. or optical measuring methods, such as light scattering.

  When the average particle diameter of the granular conductor 4 is about 10 μm or less, the possibility that the granular conductor 4 becomes a three-dimensional obstacle and hinders the movement of the spherical electrode 3 is relatively small. That is, the effect of facilitating the movement of the spherical electrode 3 by the granular conductor 4 can be more effectively obtained.

  Further, when the granular conductor 4 is a material having a smaller coefficient of friction than the surface portion of the spherical electrode 3, the frictional force between the spherical electrode 3 and the planar electrode portion 2 can be effectively reduced. This facilitates the movement of the spherical electrode 3 due to vibration and inclination, and improves the operating characteristics as a sensor. The condition that the friction coefficient is smaller may satisfy one of the static friction coefficient and the dynamic friction coefficient, or may satisfy both.

  Therefore, the granular conductor 4 is effective in improving the operating characteristics of the vibration sensor 9 as a material having a particle diameter of 10 μm or less and a friction coefficient smaller than that of the surface portion of the spherical electrode 3. In addition, if the average particle diameter of the granular conductor 4 is 3 μm or more, the effect of reducing the resistance of sliding or rolling between the spherical electrode 3 and the planar electrode portion 2 can be more effectively obtained. Therefore, the average particle diameter of the granular conductor 4 may be in the range of 10 μm or less and 3 μm or more.

  As such a material having a relatively small coefficient of friction, for example, when the surface of the spherical electrode 3 is gold (gold plated layer), metal materials such as tungsten, molybdenum, iron, nickel and cobalt, carbon and the like can be mentioned. It is done.

  The granular conductor 4 can be produced, for example, by subjecting a raw material such as carbon in a block shape or the like to granulation such as cutting or mechanical pulverization. Further, the granular conductor 4 is added to the container part before the container part containing the spherical electrode 3 is sealed with the lid 13 as described later, for example. The granular conductor 4 is dispersed in the storage container by subsequent handling or the like, whereby the granular conductor 4 is disposed between the planar electrode portion 2 and the spherical electrode 3.

  Further, the granular conductor 4 may be arranged in advance on at least one surface of the planar electrode portion 2 and the spherical electrode 3. In the example shown in FIG. 3, a part of the plurality of granular conductors 4 bite into the surface portion of the spherical electrode 3. In other words, the granular conductor 4 includes one partially fitted into the spherical electrode 3. In this case, the relatively hard granular conductor 4 made of carbon or the like can easily fit into the surface portion of the spherical electrode 3 made of relatively soft gold or the like and mechanically joined.

  In this case, the hardness of the granular conductor 4 may be larger than the hardness of the surface portion of the spherical electrode 3. The hardness of the surface portions of the granular conductor 4 and the spherical electrode 3 can be measured by a measuring method such as a Vickers hardness test or a Knoop hardness test, for example. Alternatively, a method may be used in which the granular conductor 4 and the surface portion of the spherical conductor 3 are rubbed with each other and the one not scratched is detected as having a higher hardness. That is, the hardness of the surface portions of the granular conductor 4 and the spherical conductor 3 does not have to be quantified as a numerical value such as Vickers hardness, for example, and the relative hardness with the surface portions of the granular conductor 4 and the spherical conductor 3 It only needs to be able to compare.

  The density of the arrangement of the granular conductor 4 interposed between the planar electrode portion 2 and the spherical electrode 3 is, for example, as an area ratio in a range where the planar electrode portion 2 and the spherical electrode 3 overlap with each other in plan view. What is necessary is just about 5 to 30%.

  On the lower surface of the substrate 11, as shown in FIGS. 5 and 10, for example, a pair of lower surface metallization layers 5 are provided along two opposing sides of the substrate 11. The pair of lower surface metallized layers 5 are formed in a rectangular shape. Then, one 5 a of the pair of lower surface metallized layers 5 is provided along one side of the substrate 11. In addition, the other 5 b of the pair of lower surface metallized layers 5 is provided along the other side of the substrate 11 with a gap between the other side 5 a. On the other hand, 5 a is electrically connected to both of the first through conductors connected to the second metallized layer 6 b and the through conductor in the frame. The other 5 b is electrically connected to one connected to the first metallized layer 6 a. The lower surface metallization layer 5 is made of a conductive material, for example, a metal material such as tungsten, molybdenum, manganese, nickel, copper, silver, gold or aluminum. The lower surface metallized layer 5 may be made of an alloy material of those. The lower surface metallization layer 5 may be made of a composite material in which a plurality of materials among these materials are mixed.

  The lid 13 is provided on the frame 12 so as to cover the second electrode 22 and the spherical electrode 3. The lid 13 has a function of sealing a space surrounded by the substrate 11 and the frame 12. The lid 13 is joined to the third metallized layer 6c on the top surface of the frame 12 via, for example, a gold-tin solder. The lid 13 is made of, for example, a metal material such as iron, nickel, cobalt, copper, silver, gold, or aluminum. In addition, the lid 13 may be made of an alloy material including those metal materials. Alternatively, the lid 13 is made of a composite material in which a plurality of materials of these materials are mixed.

  The lid 13 is electrically connected to the third metallized layer 6c as the wiring conductor, the in-frame through conductor, and the first through conductor. The lid 13 is electrically connected to one side 5 a of the lower surface metallized layer 5 through the inside of the frame 12 and the substrate 11. In addition, lid 13 has the same potential as second metallized layer 6 b and first electrode 21 electrically connected via the inner layer wiring conductor of substrate 11 electrically connected to the first through conductor.

  The third electrode 23 may be disposed on the lower surface of the lid 13. That is, the planar electrode unit 2 in the vibration sensor 9 according to the embodiment may further include the third electrode 23 located on the lower surface of the lid 13. For example, if the lid 13 is made of a metal material, the third electrode positioned on the lower surface of the lid 13 is electrically connected to the in-frame through conductor by the lid 13 main body. Thus, the third electrode 23 is electrically connected to the outside.

  When the third electrode 23 is present, for example, even if the vibration sensor 9 is turned upside down, detection of vibration is easily performed. That is, in this case, the spherical electrode 3 moves on the third electrode 23 and hits the inside of the second electrode 22 due to the vibration or inclination of the device such as the electronic device on which the vibration sensor 9 is mounted. As a result, a change occurs in the electrical conduction between the spherical electrode 3 and the third electrode 23. As a result, the vibration sensor 9 can detect that vibration or tilt has occurred in the electronic device.

  In each of the above examples, the vibration sensor 9 may be such that the uppermost part of the upper surface of the first electrode 21 is located above the opening end of the recess 14. In addition, the outer periphery of the upper surface of the first electrode 21 may be positioned above the opening end of the recess 14.

  When the uppermost portion of the upper surface of the first electrode 21 is positioned above the open end of the recess 14, the contact of the spherical electrode 3 with the second electrode 22 can be made more reliable. That is, when the spherical electrode 3 is rolled from the uppermost position of the upper surface of the first electrode 21 to a lower position, a part of the substrate 11 is not easily interposed between the spherical electrode 3 and the second electrode 22 . Therefore, the possibility that the spherical electrode 3 contacts the substrate 11 is reduced. In other words, the spherical electrode 3 is not obstructed by a part of the substrate 11 and can easily come into contact with the second electrode 22 without contacting the substrate 11. As a result, the possibility that the sensitivity of the vibration sensor 9 for detecting the vibration of the electronic device may be reduced. In addition, wear of the substrate 11 or the spherical electrode 3 due to the spherical electrode 3 coming into contact with the open end of the recess 14 can be suppressed. Therefore, the long-term reliability of the vibration sensor 9 can be improved.

  The first electrode 21 is not limited to the conductive plate as described above, and may be a metal layer (not shown) such as a metallized layer located on the upper surface of the substrate 11. The metallized layer as the first electrode 21 can be formed by the same material and method as the first metallized layer 6a. Also, a plating layer of nickel, gold or the like may be provided on the exposed surface of this metallized layer. As metal layers other than a metallized layer, metal foil, a plating layer, etc. are mentioned, for example.

  The present invention is not limited to the above-described embodiment, and various changes, improvements, and the like can be made without departing from the scope of the present invention.

  For example, with regard to the granular conductor 4, ones mechanically joined to the surface portion of the planar electrode portion 2 and those mechanically joined to the surface portion of the spherical electrode 3 have different materials or particle diameters from each other. Also good.

  In addition, the first through conductor may be plural. In this case, it is advantageous to enhance the effect of heat radiation to the outside through the first through conductor. In addition, it is advantageous in reducing the conduction resistance of the electrical connection to the outside through the first through conductor.

  Moreover, you may coat | cover the surface of the metal part exposed outside, such as a 1st penetration conductor, with plating layers, such as nickel and gold | metal | money. The plating layer can suppress deterioration such as oxidation of the exposed metal portion. In addition, the wettability of the brazing material can be improved when the metal portion is connected to an external member (the terminal of the circuit board or the housing of the sensor device or the like) by a low melting brazing material such as solder.

  Further, through conductors (second through conductors) other than the first through conductor may be provided on the substrate 11. The second through conductor is formed, for example, through a part of the substrate 11 in the thickness direction. The second through conductors located above and below each other in the substrate 11 may be separated from each other in plan view. In this case, the upper and lower second through conductors can be electrically connected to each other via an internal conductor (not shown) provided in the substrate 11.

<Method of manufacturing vibration sensor>
Here, a manufacturing method of the vibration sensor 9 shown in FIG. 1 will be described.

  First, the substrate 11 is prepared. When the substrate 11 is made of, for example, an aluminum oxide sintered body, a mixture obtained by adding and mixing an organic binder, a plasticizer, a solvent and the like to raw material powders such as aluminum oxide, silicon oxide, magnesium oxide and calcium oxide Mold green sheets.

  Moreover, a high melting point metal powder such as tungsten or molybdenum is prepared, and an organic binder, a plasticizer, a solvent, or the like is added to and mixed with the powder to obtain a metal paste.

  Then, the green sheet to be the upper layer of the substrate 11 is subjected to punching processing such as punching and filled with metal paste to form a first through conductor. Then, on the upper surface of the green sheet to be the upper layer of the substrate 11, a metal paste is applied to form the first metallized layer 6a using, for example, a screen printing method so as to be electrically connected to the first through conductor. . Similarly, the green sheet as the lower layer of the substrate 11 is subjected to punching or the like and filled with a metal paste to form a first through conductor. Then, the second metallized layer 6 b and the inner layer wiring conductor are formed on the upper surface of the green sheet, which is the lower layer of the substrate 11, using screen printing, for example, so as to be electrically connected to the first through conductor. On the lower surface, lower surface metallization layer 5 electrically connected to the first through conductor is formed.

  Further, in the green sheet in the upper layer of the substrate 11 in the green sheet state, a perforated portion to be the concave portion 14 is formed in advance by mechanical processing such as punching (punching) using a die. The green sheet to be the lower layer of the substrate 11 is laminated so that the first through conductors provided on the upper layer and the lower layer of the substrate 11 are electrically connected under the perforated portion of the upper layer of the substrate 11 14 is configured. Then, the green sheet to be the upper layer and the lower layer of the substrate 11 described above and the frame 12 made of the green sheet prepared by the same method as the substrate 11 are laminated to integrally provide the unbaked substrate 11 and the frame 12 By firing at a temperature of about 1600 ° C., the integrally provided substrate 11 and frame 12 can be obtained. The first metallized layer 6a, the second metallized layer 6b, and the third metallized layer 6c are subjected to nickel plating on the surface.

  Next, the first electrode 21, the second electrode 22, the spherical electrode 3 and the lid 13 are prepared. These can be produced in a predetermined shape by using a metal processing method such as metal polishing on an ingot obtained by casting and solidifying a molten metal material into a mold.

  Next, the first electrode 21 is connected to the second metallized layer 6b provided in the concave portion 14 of the prepared substrate 11 after sintering by silver brazing. Further, the second electrode 22 is connected to the first metallized layer 6 a on the substrate 11 by silver brazing. The granular conductor 4 is disposed in a portion surrounded by the planar electrode portion 2 in the step of brazing or in the step prior thereto. The granular conductor 4 can be produced, for example, by subjecting a raw material of carbon to mechanical processing as described above. Also, the granular conductor 4 may be mechanically joined to the surface of the spherical electrode 3 or the like. This mechanical joining can be performed, for example, by pressing the spherical electrode 3 with a predetermined pressure onto the surface of a base or the like on which the granular conductors 4 are dispersed.

  Furthermore, the lid 13 is soldered to the third metallized layer 6c on the frame 12 with gold-tin solder in a state where the spherical electrode 3 is disposed in the region surrounded by the second electrode 22. Thus, the vibration sensor 9 can be manufactured.

1. Container part
11. ・ Board
12. ・ Frame
13.
14 ・ ・ Recess 2 ・ ・ Surface electrode
21 ・ ・ First electrode
22. Second electrode
23 · · Third electrode 3 · · Spherical electrode 4 · · Granular conductor 5 · · Lower surface metallization layer 6a · · First metallization layer 6b · · Second metallization layer 6c · · Third metallization layer 9 · · Vibration sensor sp 1 · · ·・ Gap sp2 ・ ・ Insulating space

Claims (6)

A substrate having an upper surface including a central portion and a frame-like outer peripheral portion surrounding the central portion; a frame located on the outer peripheral portion of the upper surface and surrounding the central portion in plan view; A container portion including a lid that closes the opening;
A surface including a first electrode located at the central portion of the upper surface, and a second electrode located at the outer peripheral portion of the upper surface and surrounding the first electrode away from the first electrode in plan view Electrode portion,
A spherical electrode located in the container portion and in contact with the planar electrode portion;
A vibration sensor comprising a granular conductor positioned between the planar electrode portion and the spherical electrode. The substrate has a recess in the central portion of the top surface;
The vibration sensor according to claim 1, wherein the first electrode is an electrode plate disposed in the recess.   The vibration sensor according to claim 1, wherein the planar electrode portion further includes a third electrode positioned on a lower surface of the lid.   The vibration sensor according to any one of claims 1 to 3, wherein the granular conductor is attached to the surface of at least one of the planar electrode portion and the spherical electrode.   The vibration sensor according to any one of claims 1 to 4, wherein a hardness of the granular conductor is larger than a hardness of a surface portion of the spherical electrode.   The vibration sensor according to any one of claims 1 to 5, wherein the granular conductor is a material having a particle size of 10 µm or less and a friction coefficient smaller than that of the surface portion of the spherical electrode.

Images