JP5791452B2 - Acceleration sensor - Google Patents

Description

  The present invention relates to an acceleration sensor that detects mechanical quantities such as applied acceleration and angular velocity and outputs them as electrical signals.

  An acceleration sensor, which is one of mechanical quantity sensors, is used for detecting a fall of a portable device. And in portable equipment, since it is necessary to suppress power consumption as much as possible, reduction in power consumption of the acceleration sensor itself is required.

  Thus, a normally-off type acceleration sensor that does not consume power during standby has been proposed (see, for example, Patent Document 1). Such an acceleration sensor will be described with reference to FIGS. FIG. 9 is a plan view of the acceleration sensor 101, and FIG. 10 is a view of a vertical section of the acceleration sensor 101 taken along the line DD in FIG. The acceleration sensor 101 includes a first substrate 106 and a second substrate 107 made of a flat insulating material held so as to face each other at a predetermined interval, and the first substrate 106 and the second substrate. The frame portion 102 made of an electrically conductive material and at least the surface sandwiched between and fixed to 107, and at least the surface surrounded and surrounded by the frame portion 102 and sandwiched between the first substrate 107 and made of an electrically conductive material The fixed electrode 105, and at least the surface surrounded by the frame portion 102 and surrounded by the first substrate 106 and the second substrate 107 so as to be swingably held is made of a conductive material. A movable electrode 103 having one end fixed to the frame portion 102, the other end fixed to the movable electrode 103, and a spring portion having at least a surface formed of a conductive material so as to substantially go around the movable electrode 103. 04 and the first substrate 107, one end of which is electrically connected to the frame portion 102, and the frame portion through electrode 108 made of a conductive material and the first substrate 106 are provided. A fixed electrode through electrode 109 made of a conductive material, one end of which is electrically connected to the fixed electrode 105.

  When acceleration is applied in the plane direction of the acceleration sensor 101, inertial force acts on the movable electrode 103. Since the movable electrode 103 is swingably held by the spring portion 104, the movable electrode 103 is displaced according to the action of inertial force. When the applied acceleration exceeds a predetermined magnitude, the movable electrode 103 contacts the fixed electrode 105. Since the frame part 102, the movable electrode 103, the spring part 104, and the fixed electrode 105 are all made of a conductive material, when the movable electrode 103 and the fixed electrode 105 come into contact with each other, the frame part through electrode 108 to the fixed electrode through electrode 109 Conduct until. Therefore, for example, if a predetermined voltage is applied between the frame through electrode 108 and the fixed electrode through electrode 109, the movable electrode 103 and the fixed electrode 105 are not in contact with each other when the acceleration applied to the acceleration sensor 101 is small. In addition, since no current flows between the frame portion through electrode 108 and the fixed electrode through electrode 109, power is not consumed. On the other hand, when an acceleration exceeding a predetermined magnitude is applied to the acceleration sensor 101 and the movable electrode 103 and the fixed electrode 105 come into contact with each other, a current flows between the frame portion through electrode 108 and the fixed electrode through electrode 109, and acceleration is applied. Can be detected. In addition, since the spring portion 104 is formed so as to go around the movable electrode 103 substantially, it can be detected regardless of the direction in which the acceleration is applied as long as it is in the plane direction of the acceleration sensor 101. The acceleration sensor 101 configured in this way is called a normally-off type acceleration sensor that does not consume power during standby as described above.

JP 2010-48650 A

However, the acceleration sensor 101 shown in FIGS. 9 and 10 has the following problems.
That is, in the acceleration sensor 101, the movable electrode 103 must be formed so as to surround the peripheral surface of the fixed electrode 105, and the mass of the movable electrode 103 necessary for acceleration detection needs to be sufficiently secured. The movable electrode 103 must be enlarged. Therefore, it is difficult to reduce the size of the acceleration sensor 101.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a small acceleration sensor with low power consumption.

In order to solve the above problems, the present invention provides the following means.
(1) The present invention is an acceleration sensor for detecting an applied acceleration, and includes a pair of substrates made of a flat insulating material and a hollow frame, and upper and lower surfaces of the pair of substrates. A fixed surface is composed of a frame portion made of a conductive material, and a pair of substrates facing each other and an inner peripheral surface of the frame portion with the frame portion fixed to the pair of substrates. A movable electrode whose surface is made of a conductive material and a surface which is made of a conductive material, one end is fixed to the inner peripheral surface of the frame portion, and the other end is an outer periphery of the movable electrode. At least one of the pair of substrates, and a spring portion that is fixed to a surface and is arranged so that a portion between the one end and the other end surrounds the peripheral surface of the movable electrode and holds the movable electrode in a swingable manner. A concave portion formed in a concave shape on the opposing surface of one substrate, and A fixed electrode made of a conductive thin film provided on the bottom and side walls of the part, and a frame made of a conductive material provided through the one substrate and having one end electrically connected to the surface of the frame part A fixed electrode penetrating electrode, and a fixed electrode penetrating electrode made of a conductive material provided at one end and electrically connected to the fixed electrode. Is electrically insulated, and a part of the movable electrode is accommodated in the recess, and can be brought into contact with the fixed electrode when the acceleration is applied.

  The acceleration sensor according to the present invention is a normally-off type acceleration sensor that consumes power by contacting a movable electrode made of a conductive material and a fixed electrode only when acceleration is applied. The power consumption is not bulky. Further, according to the acceleration sensor according to the present invention, since the fixed electrode is provided on the bottom surface and the side wall of the concave portion provided on the substrate, the fixed electrode is disposed at the center of the movable electrode as in the above-described prior art. There is no need to make a hole, and the outer shape of the movable electrode can be reduced if the mass is the same. That is, in the present invention, the movable electrode can be downsized, and as a result, the acceleration sensor can be downsized.

(2) Moreover, the acceleration sensor of this invention WHEREIN: The said movable electrode is provided with the contact surface facing the side wall of the said recessed part, It is characterized by the above-mentioned.
In the acceleration sensor according to the present invention, when the movable electrode and the fixed electrode come into contact with each other when acceleration is applied, the contact surface comes into contact with the fixed electrode, so that the contact area is increased and the output signal can be increased. / N ratio can be improved.

(3) Moreover, the acceleration sensor of this invention is characterized by the said contact surface being a surface parallel to the side wall of the said recessed part.
In the acceleration sensor according to the present invention, since the contact surface is a surface parallel to the side wall of the recess, the contact area between the contact surface and the fixed electrode can be further increased and the output signal can be increased. Can be further improved.

(4) In the acceleration sensor according to the present invention, the fixed electrode includes a plurality of fixed electrodes, and the fixed electrodes in contact with the movable electrode change according to the direction of the applied acceleration. The fixed electrode penetrating electrodes are arranged to be separated from each other and are electrically connected to the plurality of fixed electrodes, respectively.
In the acceleration sensor according to the present invention, the fixed electrodes that are in contact with the movable electrode change in accordance with the direction of the applied acceleration, and are arranged apart from each other so as to be insulated from each other. The direction of acceleration can be detected by examining whether the electrode is touched.

(5) In the acceleration sensor of the present invention, the plurality of fixed electrodes include a first fixed electrode provided on a bottom surface of the recess and a second fixed electrode provided on a side wall of the recess. It is characterized by becoming.
In the acceleration sensor according to the present invention, when acceleration is applied in a direction perpendicular to the bottom surface of the recess, the movable electrode contacts the first fixed electrode, and acceleration is applied in a direction parallel to the bottom surface of the recess. Since the movable electrode contacts the second fixed electrode, the acceleration is applied in the direction perpendicular to the bottom surface of the recess by examining whether the movable electrode is in contact with the first electrode or the second electrode. Or whether it is applied in a parallel direction.

(6) Further, in the acceleration sensor of the present invention, the second fixed electrode includes a plurality of pieces insulated from each other, and the plurality of second fixed electrodes are movable according to the direction of the applied acceleration. The second fixed electrode in contact with the electrode is arranged so as to be changed and spaced apart from each other.
In the acceleration sensor according to the present invention, when acceleration is applied in a direction parallel to the bottom surface of the recess, it is determined which of the directions parallel to the bottom surface of the recess by examining which fixed electrode the movable electrode contacts. It can be detected whether acceleration is applied in the direction of.

(7) In the acceleration sensor according to the aspect of the invention, the movable electrode includes a movable electrode recess formed in a concave shape on a surface facing the bottom surface of the recess, and the bottom surface of the recess is partially in the movable electrode recess. Is provided, and the fixed electrode is formed on the surface of the protruding portion, the protruding portion being disposed away from the side surface and the bottom surface of the movable electrode recessed portion in a state where the acceleration is not applied, When the acceleration is applied, the movable electrode concave portion and the protruding portion are in contact with each other.
In the acceleration sensor according to the present invention, since the fixed electrode is provided on the surface of the protruding portion, the fixed electrode can be further reduced in size, and the acceleration sensor can be reduced in size.

(8) Further, in the acceleration sensor according to the present invention, the side wall of the movable electrode recess and the side wall of the protruding portion are provided with surfaces parallel to each other.
In the acceleration sensor according to the present invention, the side wall of the movable electrode recess and the side wall of the protrusion have parallel surfaces, and therefore, when acceleration is applied and the movable electrode and the fixed electrode come into contact, the side wall of the movable electrode recess. The contact area between the protrusion and the side wall of the protruding portion is increased, the output signal can be increased, and the S / N ratio can be improved.

(9) In the acceleration sensor according to the present invention, the fixed electrode includes a plurality of insulated electrodes, and the plurality of second fixed electrodes are in contact with the movable electrode according to the direction of applied acceleration. The second fixed electrodes that are in contact with each other are arranged so as to be separated from each other so as to be changed.
In the acceleration sensor according to the present invention, since the fixed electrode includes a plurality of fixed electrodes, the fixed electrode with which the movable electrode contacts varies depending on the direction of the acceleration applied to the acceleration sensor. Therefore, the direction of acceleration can be detected by examining which fixed electrode is in contact.

  According to the present invention, it is possible to reduce the size of the movable electrode and the fixed electrode while not consuming electric power during standby, and thus it is possible to provide a small acceleration sensor that consumes less power.

It is a top view which shows 1st Embodiment of the acceleration sensor concerning this invention. It is sectional drawing which shows 1st Embodiment of the acceleration sensor concerning this invention. It is sectional drawing which shows 2nd Embodiment of the acceleration sensor concerning this invention. It is a top view which shows 3rd Embodiment of the acceleration sensor concerning this invention. It is sectional drawing which shows 3rd Embodiment of the acceleration sensor concerning this invention. It is sectional drawing which shows 4th Embodiment of the acceleration sensor concerning this invention. It is a top view which shows 5th Embodiment of the acceleration sensor concerning this invention. It is sectional drawing which shows 5th Embodiment of the acceleration sensor concerning this invention. It is a top view which shows the conventional acceleration sensor. It is sectional drawing which shows the conventional acceleration sensor.

(First embodiment)
Hereinafter, a first embodiment of an acceleration sensor according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view of the acceleration sensor 1 according to the present embodiment, and FIG. 2 is a view of a vertical section of the acceleration sensor 1 taken along the line AA in FIG. For simplicity, FIG. 1 omits a first substrate, a second substrate, a fixed electrode, and a through electrode, which will be described later.

  The acceleration sensor 1 includes a first substrate 6 and a second substrate 7 (a pair of substrates) held so as to face each other at a predetermined interval, and a second substrate 7 of the first substrate 6. The frame is sandwiched between the first substrate 6 and the second substrate 7 and the concave portions 9 and 90 provided on the surface facing the first substrate 6 and the surface of the second substrate 7 facing the first substrate 6. A gap portion 20 formed in a portion sandwiched between the portion 2, the first substrate 6, the second substrate 7, and the frame portion 2, a movable electrode 3 disposed in the gap portion 20, and a movable electrode 3, the spring part 4 arranged so as to surround the peripheral surface of the recess 3, the fixed electrode 5 provided on the bottom surface and the side wall of the recess 9, and the first substrate 6, one end being electrically connected to the frame part 2. Connected through the frame portion through electrode 8 and the fixed electrode through electrode 1 provided through the first substrate 6 and electrically connected to the fixed electrode 5 at one end. It has a, and.

  The first substrate 6 and the second substrate 7 are each made of a flat insulating material. As the insulating material, for example, glass such as fused quartz, borosilicate glass, soda lime glass, ceramic, or the like can be used. Then, as shown in FIG. 2, the first substrate 6 and the second substrate 7 are respectively formed with recesses 9 and 90 on the surfaces facing the second substrate 7 and the first substrate 6.

  The concave portions 9 and 90 are depressions having a trapezoidal cross-sectional shape formed so that the area on the bottom surface side is smaller than the opening side from the facing surfaces of the first substrate 6 and the second substrate 7 shown in FIG. It is. In addition, the recessed parts 9 and 90 should just be concave shape, and are not limited to cross-sectional view trapezoid shape.

  The frame portion 2 is provided so as to be sandwiched between the first substrate 6 and the second substrate 7 in the vertical direction, and is a hollow frame that vertically connects the first substrate 6 and the second substrate 7. (Frame). The frame 2 is formed in a square shape when viewed from above. That is, the frame portion 2 is fixed at a portion where the concave portion 9 is not formed on the lower surface of the first substrate 6 on the upper surface, and the lower surface is a portion where the concave portion 90 is not formed on the upper surface of the second substrate 7. Fixed. Further, at least the surface of the frame portion 2 is made of a conductive material such as gold, platinum, copper, or aluminum.

  The gap portion 20 includes a facing surface between the lower surface of the first substrate 6 and the second substrate 7 (that is, the lower surface of the first substrate 6 and the upper surface of the second substrate 7), and the inner peripheral surface of the frame portion 2. And is a hermetically sealed hollow portion formed by the above, and seals the movable electrode 3 inside.

  The movable electrode 3 is an electrode that is disposed in the gap portion 20 and supported by the spring portion 4. Specifically, the movable electrode 3 is accommodated in a state where the upper end portion and the lower end portion are spaced apart from the bottom surfaces of the recesses 9 and 90 in the vertical direction, and at a predetermined interval from the inner peripheral surface of the frame portion 2 in the horizontal direction. It is enclosed by the said frame part 2 in the state which separated. The movable electrode 3 has a surface made of a conductive material such as gold, platinum, copper, or aluminum.

  The spring portion 4 is a member having a shape such that one end is connected to the frame portion 2, the other end is connected to the movable electrode 3, and the portion between the one end and the other end surrounds the peripheral surface of the movable electrode 3. That is, the spring portion 4 supports the movable electrode 3 in a swingable manner according to the direction / magnitude of the acceleration applied to the acceleration sensor 1 and horizontally moves the movable electrode 3 in a state where no acceleration is applied to the acceleration sensor 1. To support. The spring portion 4 is an elastic member such as silicon, and at least the surface thereof is made of a conductive material such as gold, platinum, copper, or aluminum.

  The fixed electrode 5 is an electrode provided on the lower surface of the first substrate 6 over the bottom surface and side walls of the recess 9 (and the lower end of the fixed electrode through electrode 13). The fixed electrode is made of a conductive thin film such as gold, platinum, copper, or aluminum. Note that the fixed electrode 5 and the frame portion 2 are not connected to each other and are electrically insulated.

The frame portion penetration electrode 8 is provided through the vertical direction of the first substrate 6 at a horizontal position where the frame portion 2 is provided so that one end (lower end) is electrically connected to the frame portion 2. Electrode.
The fixed electrode through electrode 13 is provided so as to penetrate the vertical direction of the first substrate 6 at a horizontal position where the fixed electrode 5 is provided so that one end (lower end) is electrically connected to the fixed electrode 5. Electrode.

(Operation of acceleration sensor 1)
When acceleration is applied to the acceleration sensor 1 configured as described above, an inertial force corresponding to the acceleration acts on the movable electrode 3. Since the movable electrode 3 is swingably held by the spring portion 4, it is displaced according to the action of inertial force. In particular, when the applied acceleration exceeds a predetermined magnitude, the movable electrode 3 contacts the fixed electrode 5. Therefore, since the frame part 2, the movable electrode 3 and the spring part 4 are all made of a conductive material and the fixed electrode 5 is made of a conductive thin film, when the movable electrode 3 and the fixed electrode 5 come into contact with each other, the frame part The through electrode 8 and the fixed electrode through electrode 13 are electrically connected. Therefore, for example, if a predetermined voltage is applied between the frame portion through electrode 8 and the fixed electrode through electrode 13, the movable electrode 3 and the fixed electrode 5 are brought into contact with each other when the acceleration applied to the acceleration sensor 1 is small. In addition, since no current flows between the frame portion through electrode 8 and the fixed electrode through electrode 13, no power is consumed. On the other hand, when an acceleration exceeding a predetermined magnitude is applied to the acceleration sensor 1 and the movable electrode 3 and the fixed electrode 5 come into contact with each other, a current flows between the frame portion through electrode 8 and the fixed electrode through electrode 13 to apply acceleration. Can be detected. Further, since the spring portion 4 is formed so as to surround the peripheral surface of the movable electrode 3, the movable electrode 3 can be displaced in the plane direction in the plane direction of the acceleration sensor 1, and can contact the fixed electrode 5. It can be detected no matter which direction the acceleration is applied. Further, since the fixed electrode 5 is also formed on the bottom surface of the recess 9, even if acceleration is applied in the vertical direction of the acceleration sensor 1, the movable electrode 3 and the fixed electrode 5 can be brought into contact with each other, and the acceleration can be detected. it can. The acceleration sensor 1 configured as described above is a normally-off type acceleration sensor that does not consume power during standby.

  Further, the conventional acceleration sensor 101 shown in FIGS. 9 and 10 is arranged such that the fixed electrode 105 is surrounded by the movable electrode 103, whereas in the acceleration sensor 1 of the present embodiment, the fixed electrode 5 is the first. The substrate 6 is provided. Therefore, it is not necessary to make a hole for disposing the fixed electrode 105 at the center of the movable electrode 3, and the outer shape of the movable electrode 3 can be reduced with the same mass. As a result, the acceleration sensor 1 can be reduced in size.

(Second Embodiment)
Next, a second embodiment according to the present invention will be described with reference to FIG. In the second embodiment, the same portions as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
FIG. 3 is a cross-sectional view showing an acceleration sensor 1a according to the second embodiment.

  In the acceleration sensor 1a of the second embodiment, when the movable electrode 3 comes into contact with the side wall of the recess 9 between the side surface and the upper surface, which are the surfaces facing the fixed electrode 5, the surface contact with the side wall is possible. It is characterized by comprising a shape having a contact surface 10 which is a surface.

  For example, acceleration is applied to the acceleration sensor 1 configured as described above in the left-right direction of the acceleration sensor 1a shown in FIG. 3 or the normal direction of the contact surface 10, and the movable electrode 3 and the fixed electrode 5 come into contact with each other. Sometimes, the contact surface 10 of the movable electrode 3 comes into surface contact with the fixed electrode 5 provided on the side wall of the recess 9. That is, according to the acceleration sensor 1a, the contact area between the movable electrode 3 and the fixed electrode 5 is increased and the output signal can be increased, so that the S / N ratio can be improved. In particular, if the contact surface 10 is arranged substantially parallel to the side wall of the recess 9, the contact area between the contact surface 10 and the fixed electrode 5 can be further increased, so that the S / N ratio can be further improved. be able to.

(Third embodiment)
Next, a third embodiment according to the present invention will be described with reference to FIG. 4 and FIG. In the third embodiment, the same portions as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
FIG. 4 is a plan view of the acceleration sensor 1b according to the third embodiment, and FIG. 5 is a view of a vertical section taken along line BB in FIG. 4 as viewed in the direction of the arrow. For simplicity, FIG. 4 omits a first substrate and a second substrate described later.

  In the acceleration sensor 1b according to the third embodiment, the first fixed electrode 5b made of a conductive thin film provided on the bottom surface of the recess 9 and the side surface of the movable electrode 3 disposed on the side surface of the recess 9 can contact each other. The second fixed electrode 5c, the third fixed electrode 5d, the fourth fixed electrode 5e, the fifth fixed electrode 5f, and the first fixed electrode 5 are provided so as to penetrate through the first fixed electrode 5c. The first fixed electrode through electrode 13b, the second fixed electrode 5c, the third fixed electrode 5d, the fourth fixed electrode 5e, and the fifth fixed electrode 5f, which are electrically connected to the electrode 5b, the second fixed electrode 5c, the fourth fixed electrode 5e, and the second fixed electrode 5f, respectively. A fixed electrode through electrode 13c, a third fixed electrode through electrode 13d, a fourth fixed electrode through electrode 13e, and a fifth fixed electrode through electrode 13f are provided.

  That is, the fixed electrode 5 integrally formed in the first embodiment and the second embodiment is replaced with the bottom surface of the concave portion 9 like the first fixed electrode 5b to the fifth fixed electrode 5f in this embodiment. And four side surfaces are separated from each other. In addition, with the separation of the fixed electrodes, the fixed electrode through electrodes 13 are also arranged in a separated state as in the first fixed electrode through electrodes 13b to the fifth fixed electrode through electrodes 13f.

  When acceleration is applied to the acceleration sensor 1 configured as described above, the movable electrode 3 comes into contact with any one of the fixed electrodes from the first fixed electrode 5b to the fifth fixed electrode 5f depending on the direction of the acceleration. Therefore, the acceleration applied to the acceleration sensor 1 is determined by examining which through electrode of the frame portion through electrode 8 and the first fixed electrode through electrode 13b to the fifth fixed electrode through electrode 13f are conducted. Can be detected.

  In the present embodiment, the acceleration sensor 1 having a plurality of fixed electrodes from the first fixed electrode 5b to the fifth fixed electrode 5f has been described. However, for example, the fixed electrode is a first fixed electrode provided on the bottom of the recess 9 and a second fixed electrode provided on the side wall of the recess 9 (that is, the second fixed electrode 5c to the fifth fixed electrode 5f). It is also possible to use an acceleration sensor configured to include a fixed electrode integrally formed. In this case, out of the acceleration applied to the acceleration sensor, the acceleration applied perpendicularly to the acceleration sensor and the acceleration applied in parallel to the acceleration sensor are detected separately and applied in parallel to the acceleration sensor. The acceleration can also be operated as a non-directional acceleration sensor that detects regardless of the direction.

  Further, for example, in order to cause the acceleration sensor 1b to function as a higher performance omnidirectional acceleration sensor, it is of course possible to adopt a configuration that can detect acceleration in the vertical direction by providing a fixed electrode on the bottom surface of the recess 90. Good.

(Fourth embodiment)
Next, a fourth embodiment according to the present invention will be described with reference to FIG. In the fourth embodiment, the same portions as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
FIG. 6 is a sectional view showing the acceleration sensor 1 of the fourth embodiment.

  In the acceleration sensor 1c of the fourth embodiment, the movable electrode recess 11 that is a concave depression provided on the upper surface of the movable electrode 3, the protrusion 12 provided on the bottom surface of the recess 9, and the surface of the protrusion 12 And a fixed electrode 5 made of a conductive material provided on the bottom surface of the recess 9.

  Here, the protrusion 12 has a shape that can be inserted into the movable electrode recess 11, and when the acceleration is applied to the acceleration sensor 1 c in the vertical direction, a part is accommodated in the movable electrode recess 11. Further, the protrusion 12 is arranged at a predetermined interval from the side surface and the bottom surface of the movable electrode recess 11 in a state where no acceleration is applied to the acceleration sensor 1c.

  When acceleration is applied to the thus configured acceleration sensor 1 c, the movable electrode 3 is displaced by the action of inertial force, contacts the fixed electrode 5, and between the frame portion through electrode 8 and the fixed electrode through electrode 13. Therefore, the acceleration applied to the acceleration sensor 1 can be measured.

  The fixed electrode 5 is partly accommodated in the movable electrode recess 11 and is disposed at a predetermined distance from the side surface and the bottom surface of the movable electrode recess 11, so that the side surface of the recess 9 faces the side surface of the movable electrode 3. Unlike the case where it is provided, the fixed electrode 5 can be reduced in size, and the acceleration sensor 1 can be reduced in size.

  Further, if the side surface of the movable electrode recess 11 and the side surface of the protrusion 12 are formed so as to be substantially parallel, the contact area when the movable electrode 3 and the fixed electrode 5 come into contact with each other increases and the output signal increases. Therefore, the S / N ratio can be improved.

(Fifth embodiment)
Next, a fifth embodiment according to the present invention will be described with reference to FIGS. In the fifth embodiment, the same portions as those in the fourth embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
FIG. 7 is a plan view of the acceleration sensor 1 of the fifth embodiment, and FIG. 8 is a view of a vertical section taken along the line CC in FIG. 7 as viewed in the direction of the arrow. For simplicity, FIG. 8 omits a first substrate and a second substrate described later.

  In the acceleration sensor 1d according to the fifth embodiment, the first fixed electrode 5b and the second fixed electrode 5c made of a conductive thin film are provided on the surface of the protruding portion 12 so as to face the side surfaces of the movable electrode 3, respectively. A third fixed electrode 5d, a fourth fixed electrode 5e, and a first fixed electrode 5b, a second fixed electrode 5c, and a third fixed electrode. First fixed electrode through electrode 13b, second fixed electrode through electrode 13c, third fixed electrode through electrode 13d, and fourth fixed electrode electrically connected to 5d and fourth fixed electrode 5e And a through electrode 13e.

  That is, the fixed electrode 5 integrally formed in the fourth embodiment is replaced with the concave portion 9 connected to the protruding portion 12 like the first fixed electrode 5b to the fourth fixed electrode 5e in the present embodiment. The four bottom surfaces are arranged separately. In addition, with the separation of the fixed electrodes, the fixed electrode through electrodes 13 are also arranged in a separated state as in the first fixed electrode through electrodes 13b to the fourth fixed electrode through electrodes 13e.

  When acceleration is applied to the thus configured acceleration sensor 1d, the movable electrode 3 comes into contact with any one of the fixed electrodes from the first fixed electrode 5b to the fourth fixed electrode 5e depending on the direction of the acceleration. Therefore, the direction of the acceleration applied to the acceleration sensor 1 is determined by examining the through-hole electrode 8 and which through-electrode from the first fixed electrode through electrode 13b to the fourth fixed electrode through electrode 13e. Can be detected.

1, 1a, 1b, 1c, 1d Acceleration sensor 2 Frame portion 3 Movable electrode 4 Spring portion 5 Fixed electrode (5b to 5f First fixed electrode to fifth fixed electrode)
6 1st board | substrate 7 2nd board | substrate 8 Frame part penetration electrode 9,90 Concave part 10 Contact surface 11 Movable electrode recessed part 12 Protrusion part 13 Fixed electrode penetration electrode (13b-13f 1st fixed electrode penetration electrode-5th fixation Through electrode)
DESCRIPTION OF SYMBOLS 20 Air gap part 101 Conventional acceleration sensor 102 Frame part 103 Movable electrode 104 Spring part 105 Fixed electrode 106 1st board | substrate 107 2nd board | substrate 108 Frame part penetration electrode 109 Fixed electrode penetration electrode

Claims (3)

An acceleration sensor for detecting applied acceleration,
A pair of substrates made of a flat insulating material;
A hollow frame body, the frame part of which the upper and lower surfaces are fixed to the pair of substrates and made of a conductive material;
In a state in which the frame portion is fixed to the pair of substrates, the surface disposed inside the gap formed by the surfaces of the pair of substrates facing each other and the inner peripheral surface of the frame portion is conductive. A movable electrode made of a material;
The surface is made of a conductive material, one end is fixed to the inner peripheral surface of the frame portion, the other end is fixed to the outer peripheral surface of the movable electrode, and the peripheral surface of the movable electrode is between the one end and the other end. A spring portion arranged so as to surround and hold the movable electrode in a swingable manner;
A recess formed in a concave shape on the facing surface of at least one of the pair of substrates;
A fixed electrode made of a conductive thin film provided on the bottom and side walls of the recess;
A frame part penetrating electrode made of a conductive material provided through the one substrate and having one end electrically connected to the surface of the frame part;
A fixed electrode through electrode made of a conductive material provided through the one substrate and having one end electrically connected to the fixed electrode;
With
The fixed electrode and the frame portion are electrically insulated,
The movable electrode is partially housed within the recess, Ri the fixed electrode can abut der when the acceleration is applied,
The movable electrode includes a movable electrode recess formed in a concave shape on a surface facing the bottom surface of the recess,
The bottom surface of the concave portion includes a convex protruding portion that is partly accommodated in the movable electrode concave portion and is spaced apart from the side surface and the bottom surface of the movable electrode concave portion in a state where the acceleration is not applied,
The fixed electrode is formed on the surface of the protrusion,
When the acceleration is applied, the movable electrode concave portion and the protrusion come into contact with each other. The acceleration sensor according to claim 1 , wherein the side wall of the movable electrode recess and the side wall of the protruding portion have surfaces parallel to each other. The fixed electrode is composed of a plurality insulated from each other,
The plurality of second fixed electrodes are arranged apart from each other in a state of being insulated from each other so that the second fixed electrodes contacting the movable electrode change according to the direction of applied acceleration. The acceleration sensor according to claim 1 or 2 .

Images