JP6205582B2 - Sensor - Google Patents

Description

  The present invention relates to an inertial force sensor such as an acceleration sensor or an angular velocity sensor used in a vehicle, a navigation device, a portable terminal, or the like, or a sensor such as a strain sensor or an atmospheric pressure sensor.

  FIG. 14 is a cross-sectional view of an acceleration sensor 10 which is an example of a conventional sensor. As shown in FIG. 14, the conventional acceleration sensor 10 includes a substrate 12, a support portion 13 provided on the upper surface of the substrate 12, a weight portion 14 facing the upper surface of the substrate 12, and one end connected to the support portion 13. The other end of the beam portion 15 is connected to the weight portion 14, and the protrusion portion 16 is provided on the lower surface of the weight portion 14.

  As prior art document information relating to this conventional acceleration sensor, for example, Patent Document 1 is known.

JP 2007-132863 A

  FIG. 15 is a schematic cross-sectional view seen from the direction A in FIG. 14. FIG. 15A is a schematic view when no acceleration is applied, and FIG. 15B is a schematic view when excessive acceleration is applied in the X-axis direction. FIG. As shown in FIG. 15B, when excessive acceleration is applied in the X-axis direction, the beam portion 15 is twisted about the Y-axis, and the beam portion 15 is bent due to this twist. There was a problem that it would end up.

  Therefore, the sensor of the present invention includes a first substrate, a support portion connected to the first substrate, a weight portion facing the first substrate, one end connected to the support portion, and the other end. Are connected to the weight, the first and second protrusions provided on the first substrate, the second substrate facing the weight, and the second substrate. And third and fourth protrusions provided. Here, it is assumed that the distance between the first protrusion and the second protrusion is smaller than the distance between the third protrusion and the fourth protrusion.

  With this configuration, it is possible to effectively suppress the stress on the beam portion due to the torsion of the weight portion, so that the impact resistance of the sensor can be improved.

Schematic diagram of acceleration sensor according to Embodiment 1 Diagram showing a circuit example of the sensor Illustration of the effect of the sensor Action diagram of force of the sensor Sectional drawing of the acceleration sensor in Embodiment 2 Sectional drawing of the acceleration sensor of the other example in Embodiment 2 Sectional drawing of the acceleration sensor of another example in Embodiment 2 Schematic diagram of acceleration sensor according to Embodiment 3 Illustration of the effect of the sensor Schematic diagram of another example acceleration sensor according to Embodiment 3 Explanatory drawing of the effect of the acceleration sensor of the other example in Embodiment 3 Schematic diagram of acceleration sensor according to Embodiment 4 Cross section of the sensor Cross-sectional view of a conventional acceleration sensor Another cross-sectional view of a conventional acceleration sensor

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a schematic diagram of an acceleration sensor 100 according to the first embodiment. 1A is a top view of the acceleration sensor 100, and FIG. 1B is a diagram in which the acceleration sensor 100 of FIG. 1A is projected onto the YZ plane from the positive X-axis direction. Here, the direction in which the beam portion 104 extends from the support portion 102 is the Y-axis direction, the direction perpendicular to the direction in which the beam portion 104 extends from the support portion 102 is the X-axis direction, and the thickness direction of the weight portion 103, A direction perpendicular to the X axis and the Y axis is expressed as a Z axis direction. In all the subsequent drawings, the method for determining the X axis, the Y axis, and the Z axis is the same.

  The acceleration sensor 100 includes a substrate 101, a support portion 102 provided on the upper surface of the substrate 101, a weight portion 103 that is disposed opposite to the upper surface of the substrate 101 and provided with a predetermined gap, and one end of the acceleration sensor 100. The beam portion 104 connected at the other end to the weight portion 103 and the upper surface of the substrate 101 in the thickness direction of the weight portion 103 (in another expression, the Z-axis direction in FIG. 1A). In projection, a projection 105 and a projection 106 are provided so as to overlap the weight 103. Here, the width D 1 of the weight portion 103 is larger than the width D 2 of the beam portion 104. Distance D3 between the protrusion 105 and the protrusion 106 (a surface from the end of the weight 103 of the protrusion 105 near the end in the positive direction of the X axis and a surface from the end of the weight 103 of the protrusion 106 in the negative direction of the X axis) Is greater than the width D2 of the beam portion 104 and smaller than the width D1 of the weight portion 103.

  The operation of the acceleration sensor 100 configured as described above will be described.

  FIG. 2 is a circuit example when the strain resistance method is used as the detection units 107 and 108. R1 is a resistor corresponding to the detection unit 107, R4 is a resistor corresponding to the detection unit 108, and R2 and R3 are resistors provided on the support unit 102 as a reference. As shown in FIG. 2, R1, R2, R3, and R4 are connected in a bridge shape, a voltage Vin is applied between a pair of opposing contacts Vdd and GND, and a potential difference Vout between the other pair of contacts V1 and V2 is set. To detect. When acceleration is applied to the acceleration sensor 100, a potential difference Vout corresponding to the acceleration is output, and this is detected to detect acceleration. With reference to FIG. 3, the impact resistance improvement effect in the acceleration sensor 100 according to the present embodiment will be described.

  FIG. 3A is a cross-sectional view of the acceleration sensor 100 viewed from the direction C in FIG. When an impact (excessive acceleration) is applied in the positive direction of the X axis, it is twisted in the R direction around an axis Y1 that is parallel to the Y axis and passes through the center of gravity of the weight portion 103. At this time, the lower surface 103a of the weight portion 103 abuts on the protrusion 106, and the twist of the weight portion 103 in the R direction is restricted. Here, the distance D3 between the protruding portion 105 and the protruding portion 106 (the surface of the protruding portion 105 near the end in the positive X-axis direction and the negative portion of the protruding portion 106 in the negative X-axis direction). The distance from the surface of the end portion is larger than the width D2 (not shown in FIG. 3) of the beam portion 104 and smaller than the width D1 of the weight portion 103. Thereby, the stress of the beam part 104 resulting from the twist of the weight part 103 can be reduced effectively.

  On the other hand, for comparison with FIG. 3A, FIG. 3B shows an acceleration sensor 20 (corresponding to the conventional acceleration sensor 10) as an example of a configuration in which the protruding portion 16 is provided below the central portion of the weight portion 103. .

  In the acceleration sensor 20 shown in FIG. 3B, when an impact (excessive acceleration) is applied in the positive direction of the X axis, twisting occurs in the R direction as in FIG. At this time, the weight portion 103 is twisted until the lower surface 103 a comes into contact with the protruding portion 16. As a result, the twist in the R direction becomes larger than that of the acceleration sensor 100 shown in FIG. 3A, and an excessive stress is generated in the thin beam portion 104 that supports the weight portion 103.

  Further, as shown in FIG. 1 and FIG. 3A, it is preferable that the protrusion 105 and the protrusion 106 are not exposed from the weight portion 103 when viewed from the upper surface of the weight portion 103. Thereby, as shown in FIG. 3A, the lower surface 103 a of the weight portion 103 can be brought into contact with the corner portions of the protrusion portion 105 and the protrusion portion 106. By causing the lower surface 103a of the weight part 103 to contact the corners of the protrusion part 105 and the protrusion part 106, the weight part 103 due to the twist in the R direction can be prevented from shifting in the negative direction of the X axis. The twist of the weight part 103 can be controlled effectively.

  Next, as a material for the substrate 101, the support portion 102, the weight portion 103, the beam portion 104, the projection portion 105, and the projection portion 106 of the acceleration sensor 100, silicon, fused quartz, alumina, or the like can be used. Preferably, by using silicon, it becomes easy to make a small acceleration sensor using a fine processing technique.

  As a method for bonding the substrate 101 and the support portion 102, bonding with an adhesive, metal bonding, room temperature bonding, anodic bonding, or the like can be used. Among these, an adhesive such as an epoxy resin or a silicon resin is used as the adhesive. By using a silicon-based resin having a small elastic constant as the adhesive, it is possible to reduce the stress caused by the curing of the adhesive itself.

  FIG. 4 is a diagram illustrating forces acting on the weight portion 103 and the protrusions 105 and 106 when excessive acceleration acts on the acceleration sensor 100 in the X-axis direction. FIG. 4B is a schematic cross-sectional view of the acceleration sensor 120 in which the end portions of the protruding portion 105 and the protruding portion 106 come out of the weight portion 103 as a comparison target of the acceleration sensor 100. When an impact (excessive acceleration) is applied in the positive direction of the X-axis, the weight portion 103 is caused by the twist of the weight portion 103 in the R direction at the point where the projection portion 106 and the weight portion 103 in FIG. In contrast, a force f acts in the X-axis direction. The weight portion 103 is shifted in the negative direction of the X axis by the force f. On the other hand, as shown in FIG. 4A, in the acceleration sensor 100, when an impact (excessive acceleration) is applied in the positive direction of the X axis, Due to the twist of 103 in the R direction, a force f acts on the protrusion 106 in the X-axis direction. Further, it is possible to suppress the weight 103 from shifting in the negative direction of the X-axis by the reaction force f2 of the force f acting on the weight 103.

  In the present embodiment, an example in which the strain resistance method is used for the detection units 107 and 108 that detect the acceleration formed in the beam portion 104 is described. However, a capacitance method that detects a change in capacitance is used. It goes without saying that the same effect can be obtained by forming a projection for defining the displacement of the weight even in the case of an acceleration sensor.

(Embodiment 2)
The features of the embodiment of the present invention will be described focusing on the differences from the first embodiment.

  FIG. 5 is a cross-sectional view of the acceleration sensor 200 of the present embodiment. 5A is a cross-sectional view of the acceleration sensor 200 viewed from the positive direction of the X axis, and FIG. 5B is a cross-sectional view viewed from the direction E. FIG. The difference from the first embodiment is that a projection 202 and a projection 203 are provided on the upper lid 201 of the acceleration sensor 200. The distance D5 between the protrusion 202 and the protrusion 203 (the distance between the opposing surfaces of the protrusion 202 and the protrusion 203) is larger than the width D2 of the beam 104 and smaller than the distance D1 of the weight 103. In another expression, the projection 202 and a part of the projection 203 are exposed from the weight 103 in a projection view from the upper surface of the substrate 101.

  The relationship between the protrusion 105 provided on the upper surface of the substrate 101, the protrusion 106, the weight 103, and the beam 104 is the same as in the first embodiment.

  With the above configuration, the lower surface portion of the weight portion 103 is in contact with the protrusion portion 105 and the protrusion portion 106, and the upper corner portion of the weight portion 103 is in contact with the protrusion portion 202 and the protrusion portion 203. 103 torsion can be suppressed.

  In this embodiment, the protrusion 202 and the protrusion 203 are provided on the lower surface of the upper lid 201. However, as shown in FIG. 6A, the protrusion is formed on the upper surface of the weight 103 (the surface facing the upper lid 201). Even if the portion 232 and the protrusion 233 are provided, the same effect can be obtained. In this case, the relationship between the protrusions 232 and 233 provided on the upper surface of the weight portion 103 and the protrusions 105 and 106 provided on the upper surface of the substrate 101 is preferably the same as in the first embodiment.

  In the second embodiment, the protrusion 202 and the protrusion 203 provided on the lower surface of the upper lid 201 and the protrusion 105 and the protrusion 106 provided on the upper surface of the substrate 101 are shown as being formed at the same height. As shown in FIG. 7, the protrusions 225 and protrusions 226 provided on the substrate 101 have a thickness (length in the Z direction) larger than the protrusions 202 and 203 formed on the upper lid 201. It is desirable to form. With this configuration, when the weight portion 103 is torsionally displaced, the displacement in which the lower surface of the weight portion 103 comes into contact with the protruding portions 225 and 226, and the upper surface of the weight portion 103 becomes the protruding portions 202 and 203. The abutting displacement can be made the same, and there is an effect that stress due to an unnecessary torsional displacement can be reduced.

(Embodiment 3)
The features of the embodiment of the present invention will be described focusing on the differences from the first embodiment.

  FIG. 8 is a schematic diagram of the acceleration sensor 300 of the present embodiment. 8A is a top view of the acceleration sensor 300 (the substrate 101 is not shown), and FIG. 8B is a diagram in which the acceleration sensor 300 of FIG. 8A is projected onto the YZ plane from the X axis positive direction. .

  The difference from the first and second embodiments is that the acceleration sensor 300 includes a protrusion 301 between the protrusion 105 and the protrusion 106 on the upper surface of the substrate 101. By this projection 301, the overamplitude of the weight 103 in the Y-axis direction can be controlled.

  Further, as shown in FIGS. 8A and 8B, the protrusion 105, the distance D6 between the protrusion 106 and the support 102 is larger than the distance D7 between the protrusion 301 and the support 102. By forming the protrusion 105 and the protrusion 106 near the center of gravity G of the weight 103 in this manner, the weight 103 contacts the protrusion 105 and the protrusion 106 when an impact is applied to the acceleration sensor 300. Accordingly, it is possible to prevent the thin beam portion 104 from being damaged by rotating around the center of gravity G. If the protrusion 105 and the protrusion 106 are provided on the distal end side of the weight portion 103 with respect to the center of gravity G, the movable range in the Z-axis direction of the weight portion 103 is narrowed. ) Is preferably provided.

  As described above, the protrusions 105 and 106 suppress the displacement of the weight 103 due to the torsional displacement due to the acceleration in the X-axis direction, while the protrusion 301 has the weight 103 due to the acceleration in the Y-axis direction. This has the effect of suppressing the displacement.

  FIG. 9A is a schematic cross-sectional view when an excessive impact is applied to the acceleration sensor 300 in the positive direction of the Y axis and the weight portion 103 is displaced. At this time, the tip of the weight portion 103 is displaced in the positive Z-axis direction, and the root side of the weight portion 103 is displaced in the negative Z-axis direction. In this case, since the protrusion 301 is provided on the base side of the weight 103, the corner of the weight 103 abuts the upper surface of the protrusion 301, and the weight 103 is effectively displaced. Can be prevented. In particular, it is effective to form the protrusion 301 near the base of the weight portion 103 having a large displacement in the Z-axis direction, and the protrusion 301 is formed so as to straddle the main surface of the weight portion 103 on the support portion 102 side. Thus, it is possible to reliably prevent the base side of the weight portion 103 from being displaced in the negative Z-axis direction.

  On the other hand, FIG. 9B shows a case where an excessive impact is applied in the positive direction of the Z axis. As shown in FIG. 9B, the protrusion 105 and the protrusion 106 are provided closer to the center of gravity G than the protrusion 301, an excessive impact is applied, and the lower surface near the tip of the weight 103 contacts the substrate 101. Even in such a case, it is desirable that the protrusion 105, the protrusion 106, and the protrusion 301 are not in contact with each other. Further, when excessive acceleration is applied, the weight 103 can be effectively prevented from being displaced in the negative direction of the Z axis by the protrusion 105 and the protrusion 106.

  Further, by arranging the protrusions as described above, the tip of the weight part 103 first comes into contact with the substrate 101 with respect to excessive acceleration, so that the protrusions 105, 106, and 301 are normally used. Without restricting the movement of the weight portion 103 in the range (acceleration detection range), it is possible to suppress only the displacement of the weight portion due to excessive acceleration, and it is easy to secure the operation range of the weight portion 103, which is very effective. Is. In addition, the protruding portion 105, the protruding portion 106, and the protruding portion 301 can be formed in the same process, and the process can be simplified.

  FIG. 10 shows an acceleration sensor 320 according to another example of the present embodiment. 10A is a top view of the acceleration sensor 320 (the substrate 101 and the upper lid 201 are not shown), and FIG. 10B is a projection of the acceleration sensor 320 of FIG. 10A on the YZ plane from the X axis positive direction. FIG. As shown in FIG. 10, an upper lid 201 is formed on the support portion 102, and a projection 202 and a projection 203 are provided on the surface of the upper lid 201 facing the weight 103, and a projection is formed between the projection 202 and the projection 203. The part 321 may be formed. The protrusion 321 formed on the upper lid 201 is provided at a position symmetrical to the protrusion 301 provided on the substrate 101. Further, in the protrusion 202 and the protrusion 203, the distance D5 between the protrusion 202 and the protrusion 203 (the distance between the opposing surfaces of the protrusion 202 and the protrusion 203) is larger than the width D2 of the beam 104, and The weight portion 103 is provided at a position smaller than the width D1. With this configuration, the protrusions (301, 321) for suppressing the over-amplitude caused by the impact in the Y-axis direction on the lower side and the upper side of the weight part 103, and the protrusions (105 for preventing the twist in the X-axis direction, respectively. , 106, 202, 203), the impact resistance can be greatly improved.

  As shown in FIG. 6 of the second embodiment, the protruding portion 202, the protruding portion 203, and the protruding portion 321 may be formed on the upper surface of the weight portion 103 (the surface facing the upper lid 201).

  FIG. 11 is a schematic cross-sectional view of the acceleration sensor 320 when an excessive impact is applied in the positive direction of the Y axis and the weight portion 103 is displaced. In this case, the tip of the weight portion 103 is displaced in the Z-axis positive direction, and the root side of the weight portion 103 is displaced in the Z-axis negative direction. At this time, as shown in FIG. 11A, the upper surface near the tip of the weight portion 103 is in contact with the upper lid 201, but it is preferable that the protrusion is not formed in contact with the protrusion 202, the protrusion 203, and the protrusion 321. . Further, when excessive acceleration is applied and the weight 103 is displaced in the Z-axis positive direction, it is possible to effectively prevent the protrusions 202 and 203 from being displaced in the Z-axis positive direction.

  On the other hand, FIG. 11B shows a case where an excessive impact is applied in the negative direction of the Z axis. In this case, since the protrusion 321 is provided on the base side of the weight part 103, the base part of the weight part 103 abuts on the lower surface of the protrusion part 321, and the weight part 103 is effectively displaced excessively. Can be prevented.

  By arranging as shown in FIG. 10, it is possible to more surely suppress the displacement of the weight portion 103 in the Z direction due to excessive acceleration as compared with the case where the protrusion is formed only on one substrate as shown in FIG. It is excellent in that it can be done.

(Embodiment 4)
The features of the embodiment of the present invention will be described focusing on the differences from the first embodiment.

  FIG. 12 is a schematic diagram of the acceleration sensor 400 of the present embodiment. 12A is a top view of the acceleration sensor 400 (the substrate 101 is not shown), and FIG. 12B is a diagram in which the acceleration sensor 400 of FIG. 12A is projected onto the YZ plane from the X-axis positive direction. . The difference from the first to third embodiments is that the weight 401 has an angle with respect to the beam when viewed from above. Here, having an angle means that the weight portion 401 has an inclination with respect to the Y-axis direction, which is the direction in which the beam portion 104 extends, in a top view.

  Furthermore, the end 402a of the protrusion 402 and the end 401a of the weight 401 are formed such that the end 403a of the protrusion 403 and the end 401b of the weight 401 intersect with each other. In another expression, the weight portion 401 has an end portion 401a that is inclined with respect to the direction in which the beam portion 104 extends (Y-axis direction), and the projection portion 403 extends in the direction in which the beam portion 104 extends (Y-axis). The end portion 401b extends in the same direction as the direction (direction), and the end portion 401a and the end portion 401b are configured to intersect each other when viewed from the top surface of the weight portion 401. Here, although it has been described that the end portion 401a of the weight portion 401 has an inclination and the end portion 401b of the projection portion 403 extends in the same direction as the beam portion, the present invention is not limited thereto. The end 401b of the protrusion 403 may have an inclination, and the end 401a of the weight 401 may extend in the same direction as the beam.

  Details will be described. The acceleration sensor 400 includes a weight portion 401 that faces the upper surface of the substrate 101, and a protrusion 402 and a protrusion 403 provided on the upper surface of the substrate 101. The end portion 401 a of the weight portion 401 is not parallel to the end portion 402 a of the protruding portion 402. The end portion 401 b of the weight portion 401 is not parallel to the end portion 403 a of the protruding portion 403. Further, the end 401a of the weight 401 and the end 401b of the weight 401 are not parallel. The width D8 of the weight portion 401 facing the end portion of the projection 402 and the projection portion 403 near the support portion 102 is larger than the width D2 of the beam portion 104, and from the width D3 between the opposite surfaces of the projection portion 402 and the projection portion 403. Is also small. The width D9 of the weight portion 401 facing the end portion of the protrusion portion 402 and the protrusion portion 403 near the tip of the weight portion 401 is larger than the width D3 between the opposite surfaces of the protrusion portion 402 and the protrusion portion 403.

  Next, regarding the effects of the protrusion 402 and the protrusion 403, the relationship between the displacement of the weight 401 and each protrusion when an impact (excessive acceleration) is applied in the positive direction of the X axis will be described with reference to FIG. Give an explanation. FIG. 13A shows the acceleration sensor 400 according to the present embodiment, and is a cross-sectional view taken along line JJ in FIG. 12A as viewed from the direction N in FIG. Although a twist in the R direction occurs around an axis Y1 that is parallel to the Y axis and passes through the center of gravity of the weight portion 401, the weight portion 401 does not contact the protrusions 402 and 403. FIG. 13B is a cross-sectional view taken along the line KK in FIG. 12A as viewed from the direction N in FIG. As in FIG. 13A, twist is generated in the R direction, the end 401b of the weight 401 is brought into contact with the end 403a of the projection 403, and the displacement of the twist in the R direction of the weight 401 is restricted. It shows how it is. FIG.13 (c) is sectional drawing of the MM line | wire in Fig.12 (a) seen from the direction N of FIG.12 (b). As in FIG. 13A, twisting occurs in the R direction, and the lower surface 401c of the weight portion 401 comes into contact with the end portion 403a of the protrusion portion 403 (corresponding to the region where the weight portion 401 and the protrusion portion 403 overlap). The displacement of the twist of the part 401 in the R direction is restricted. As described above, by forming the protrusion 402 and the protrusion 403, the twist displacement of the weight 401 is applied to the end of the protrusion 402 and the protrusion 403 (the weight 401 and the protrusion 403 overlap in a top view. In comparison with the case where the protrusion 402 and the protrusion 403 are formed so as to be in contact with the weight 401 on the XY plane, the displacement of the twist of the weight is easily regulated. Furthermore, the effect is great, for example, sticking to the upper and lower protrusions 402 and 403 can be prevented.

  In the above embodiment, the acceleration sensor is used as an example of the sensor. However, the acceleration sensor, the angular velocity sensor, the strain sensor, The present invention can also be applied to other types of sensors such as an atmospheric pressure sensor and a pressure sensor.

  Since the sensor of the present invention can effectively suppress the breakage of the beam portion due to the twisting of the weight portion and improve the impact resistance of the sensor when an impact occurs, the vehicle, the navigation device, the portable terminal, etc. It is useful as an inertial force sensor such as an acceleration sensor and an angular velocity sensor used in the above, and a sensor such as a strain sensor and an atmospheric pressure sensor.

10, 20, 100, 120, 200, 300, 320, 400 Acceleration sensor 12, 101 Substrate 13, 102 Support portion 14, 103, 401 Weight portion 15, 104 Beam portion 16, 105, 106 Protruding portions 202, 203, 225 226, 232, 233 Protruding part 301, 321 Protruding part 402, 403 Protruding part 107, 108 Detection part 201 Upper lid

Claims (4)

A first substrate;
A support connected to the first substrate;
A weight portion facing the first substrate;
A beam portion having one end connected to the support portion and the other end connected to the weight portion;
First and second protrusions provided on the first substrate;
A second substrate facing the weight portion;
Third and fourth protrusions provided on the second substrate,
The distance between the first protrusion and the second protrusion, the third lower fence than the distance between the protruding portion and the fourth protruding portion,
In the top view as seen from the upper surface of the weight portion, the first protrusion and the second protrusion are not exposed from the weight portion, and a part of the third protrusion and the fourth protrusion. A part of the sensor is exposed from the weight portion . The distance between the first protrusion and the second protrusion, the greater than the width of the beam portion, and a sensor according to a small claim 1 than the width of the weight portion. The distance between the third protruding portion and the fourth protruding portion, the larger than the width of the beam portion, and a sensor according to a small claim 1 than the width of the weight portion. The weight portion has a first end portion that is inclined with respect to the extending direction of the beam portion,
The first protrusion has a second end extending in the same direction as the direction in which the beam extends.
The sensor according to claim 1, wherein the first end portion and the second end portion intersect in a top view from the upper surface of the weight portion.

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