JP2011174881A - Capacitance type acceleration sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitance type acceleration sensor, capable of protecting destruction due to collision between a movable part and a fixed part, when acceleration exceeding an allowable displacement value is added of the movable part. <P>SOLUTION: The capacitance type acceleration sensor includes a displaceable plumb bob 36 arranged on a substrate 35 under a dividing condition, a movable electrode 34 prepared on the plumb bob 36, a fixed electrode 33 prepared to face the movable electrode 34 to detect a change of the capacitance between both the electrodes 33 and 34 based on a displacement of the plumb bob 36. A complementary type ratcher regulating a displacement of the plumb bob 36 in the horizontal direction and a potential fixing device for fixing the potential to the complementary ratcher is prepared to both the plumb bob 36 and the substrate 35. The complementary ratcher includes a through hole 38 arranged on the plumb bob 36 and a locking member 37 arranged on the substrate 35 to be inserted into the through hole 38, so that a contact area at the time of collision is large, thereby preventing destruction due to stress concentration. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a capacitance-type acceleration sensor, and more particularly, to a capacitance-type acceleration sensor in a surface MEMS (Micro Electro Mechanical Systems), and includes a locking means for regulating horizontal displacement of a weight body. The present invention relates to a capacitive acceleration sensor provided.

  In general, a capacitive acceleration sensor has a drive electrode and a detection electrode arranged so as to sandwich a weight body (weight), a movable electrode attached to the weight body, and a movable electrode facing the movable electrode. There are known ones comprising fixed electrodes provided. Like the latter capacitive acceleration sensor, the one that detects the acceleration by changing the capacitance accompanying the change in the distance between the movable electrode and the fixed electrode is used to measure very small acceleration. The beam portion is formed to be thin and thin so that the beam portion is deformed even by a small acceleration.

  However, such an acceleration sensor has a problem that since the beam portion is thin and thin, the elastic limit of the beam portion is exceeded when a maximum acceleration is applied, and as a result, the beam portion is damaged. . Therefore, it is necessary to provide a stopper that restricts the displacement of the movable electrode in the horizontal direction.

  Further, in the capacitance type acceleration sensor that detects acceleration or the like by changing the capacitance between the movable electrode and the fixed electrode described above, in the drying process after the movable electrode and the fixed electrode are formed by etching, between the movable electrode and the fixed electrode. Due to the surface tension of the pure water interposed between them, the movable electrode and the fixed electrode facing the same adhere to each other, and the beam portion and the substrate facing the same adhere to each other.

  Also, at times other than this drying process, for example, when acceleration greater than the force determined by the spring constant of the beam portion is generated, the movable electrode is attracted to the fixed electrode, and even after the acceleration decreases, the van der There was a problem that the movable electrode and the fixed electrode would adhere due to the Waals force.

  In order to solve such a problem, for example, Patent Document 1 discloses a capacitive acceleration sensor in which a stopper is provided in the vicinity of a side portion of a beam portion in order to prevent the movable electrode from sticking to the fixed electrode. Has been proposed.

  FIG. 1 is a perspective view of a conventional capacitive acceleration sensor described in Patent Document 1. As shown in FIG. In this conventional capacitive acceleration sensor, the beam structure 152A is constructed by four anchor portions 150a, 150b, 150c, and 150d that protrude from the substrate 150, and is positioned at a predetermined interval on the upper surface of the substrate 150. Is arranged. A beam portion 151 is constructed between the anchor portion 150a and the anchor portion 150b, and a beam portion 152 is constructed between the anchor portion 150c and the anchor portion 150d. The beam portions 151 and 152 are constituted by one beam structure.

  Further, a stopper 153 is disposed on the opposite side of the weight portion 156 with respect to the beam portion 151, and a stopper 154 is disposed on the opposite side of the weight portion 156 with respect to the beam portion 152. The protrusions 153b and 154b provided on the stoppers 153 and 154 restrict the movement of the beam structure 152A in the left-right direction on the paper surface. These stoppers 153 and 154 are configured separately from the beam structure 152A and the fixing portion 152B, are fixed to the substrate 1 side via the anchor portions 153a and 154a, and are fixed to the beam via the anchor portions 150a to 150d. It is electrically connected to the structure 152A.

  With such a configuration, the movable electrode 157 does not adhere to the fixed electrode 158 even when the beam structure 152A moves. In other words, a protrusion is provided to prevent the movable electrode from sticking to the fixed electrode, and even if the movable electrode is attracted to the fixed electrode by electrostatic force, the protrusion comes into contact first, so the protrusion Compared with the case where there is not, the area which contacts a fixed electrode becomes small, and the movable electrode becomes difficult to stick to a fixed electrode.

  Further, the conventional semiconductor acceleration sensor described in Patent Document 2 is a semiconductor acceleration sensor using a piezoresistor, and the weight is placed on the weight portion on the one surface side where the cover plate is arranged. Since the projection is provided to prevent the part from sticking to the cover plate, even if the weight is attracted to the cover plate by electrostatic force during anodic bonding, the projection will contact the cover plate. Compared with the case where there is no protrusion, the area in contact with the cover plate is reduced, and the weight portion is less likely to stick to the cover plate. This patent document 2 describes that the present invention can also be used for an acceleration sensor using electrostatic capacitance.

  In addition, an acceleration sensor using the piezoresistive effect of a semiconductor crystal has been proposed in which a through hole is formed in the weight body (weight), and the displacement of the weight body is limited by passing a rod through the through hole. ing.

  FIG. 2 is a perspective view of a conventional acceleration sensor described in Patent Document 3. As shown in FIG. In this conventional acceleration sensor, a rod-like stopper 12 provided on the stem 11 is inserted into a through hole opened in the weight 13 while maintaining a qualance. Therefore, even if an excessive force is applied, the weight 13 in the X-axis direction is inserted. Displacement of the sensor chip 14 can be prevented, and damage to the sensor chip 14 can be prevented.

  In addition, the conventional capacitive acceleration sensor described in Patent Document 4 is a bent beam type sensor, and is provided with a bumper (stopper) that protrudes from the beam portion toward the weight portion. By making the interval smaller than the interval between the movable electrode and the fixed electrode, adhesion between the movable electrode and the fixed electrode is prevented.

  Further, in the conventional capacitive acceleration sensor described in Patent Document 5, a movable plate that moves in response to external acceleration has a finger, and this finger is capacitively coupled to a finger attached to a substrate. Then, the movable plate is stopped before the fingers on the movable plate collide with the fingers on the substrate by using the movement stop unit. The movement stop portion has a circular shape including a first portion that contacts the surface of the substrate and a second portion located on the first portion, and the movable plate includes a second portion of the movement stop portion. The same material and the same thickness as the movement stop. Therefore, it does not have a support structure like the present invention.

JP-A-11-230985 JP 2008-070284 A JP-A-4-194666 US Pat. No. 5,542,295 JP 11-68122 A

  However, in the above-described capacitance type acceleration sensor, when the movable part causes a rotational movement due to the acceleration applied from the outside due to the structure shape of the protrusion functioning as a stopper, the stopper and the movable part collide with each other. Since the area that acts as a limit is limited, there is a problem that stress concentration occurs in the movable part and the stopper, resulting in destruction.

  In general, when an impact force F is applied to an impacted object, the collision or damage of the impacted object occurs because the impact stress σ due to the impact load F exceeds the elastic limit of the impacted object. Assuming that the contact area at the time of collision is A, the impact stress σ per unit area due to the impact force is σ = F / A. Therefore, the larger the area in contact at the time of collision, the smaller the impact stress. Therefore, by increasing the contact area at the time of collision, it is possible to reduce the impact stress applied to the colliding object and suppress damage.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a stopper structure having a constant contact area regardless of the state of collision, and to achieve acceleration exceeding the allowable displacement amount of the movable part. On the other hand, it is an object of the present invention to provide a capacitance type acceleration sensor that is unlikely to break due to a collision between a movable part and a fixed part.

  The present invention has been made to achieve such an object, and the invention according to claim 1 provides a displaceable weight body disposed on a substrate in a separated state, and the weight body. And a fixed electrode disposed opposite to the movable electrode, and detecting a change in capacitance between the electrodes based on a displacement of the weight body. In the acceleration sensor, complementary locking means for restricting horizontal displacement of the weight body on both the weight body and the substrate, and potential fixing means for fixing a potential to the complementary locking means, Is provided.

  The invention according to claim 2 is the invention according to claim 1, wherein the complementary locking means is provided on a hole or a through hole provided in the weight body and on the substrate, It consists of a locking member inserted into a hole or a through hole.

  According to a third aspect of the present invention, in the second aspect of the present invention, the hole or the through hole is provided around the end of the weight body.

  The invention according to claim 4 is the invention according to claim 2 or 3, wherein a plurality of the holes or through holes are provided in the weight body.

  The invention according to claim 5 is the invention according to claim 2, 3 or 4, wherein the locking member is a rod-shaped member.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the weight body is attached to a support member provided on the substrate via a beam member. The potential fixing means is a conducting wire wired to the locking member, the support member, and the substrate.

  According to a seventh aspect of the present invention, there is provided a displaceable weight body arranged on the substrate in a separated state, a movable electrode provided on the weight body, and a face facing the movable electrode. A static electrode is provided that includes a fixed electrode and a fixing member that is provided on the substrate and surrounds the periphery of the weight body, and detects a change in capacitance between the electrodes based on a displacement of the weight body. The capacitive acceleration sensor is characterized in that complementary locking means for restricting a horizontal displacement of the weight body is provided on both the weight body and the fixing member.

  The invention according to claim 8 is the invention according to claim 7, wherein the complementary locking means includes a first protrusion provided at an edge of the weight body, and the fixing member. It is characterized by comprising a void portion.

  The invention according to claim 9 is the invention according to claim 7, wherein the complementary locking means includes a second protrusion provided at an edge of the weight body, and the second protrusion. And a first groove portion provided in the fixing member so as to face the protruding portion.

  The invention according to claim 10 is the invention according to claim 7, wherein the complementary locking means includes a second groove provided at an edge of the weight body, and the second groove. It consists of the 3rd projection part provided in the said fixing member facing the groove part.

  The invention described in claim 11 is characterized in that, in the invention described in claim 8, 9 or 10, the shapes of the protrusion and the groove are arcuate.

  The invention according to claim 12 is the invention according to any one of claims 7 to 11, wherein the weight body is attached to a support member provided on the substrate via a beam member. It is characterized by that.

  The invention according to claim 13 is the invention according to any one of claims 7 to 11, wherein the movable electrode is a plurality of thin plate-shaped comb movable electrodes, and the fixed electrode is the comb movable. A plurality of thin plate-like comb-shaped fixed electrodes respectively disposed opposite to the electrodes.

  The invention according to claim 14 is the invention according to claim 13, wherein the comb-shaped movable electrodes are provided on both sides in the Y-axis direction with respect to the X-axis direction which is the displacement direction of the weight body. And the comb-shaped fixed electrode is arranged to face the comb-shaped movable electrode.

  The invention according to claim 15 is the invention according to claim 13 or 14, wherein the comb-shaped fixed electrode is a pair of comb-shaped fixed electrodes sandwiching the comb-shaped movable electrode. And

  According to the present invention, the complementary locking means for restricting the horizontal displacement of the weight body is provided on both the weight body and the substrate, or on both the weight body and the fixing member, so that regardless of the direction of the collision. Since the stopper structure in which the contact area between the movable part and the fixed part is constant is provided, it is possible to prevent the movable part from being displaced more than necessary. In addition, since stress concentration is reduced with respect to the protrusion structure, it is possible to prevent the movable portion such as the weight body, the movable electrode, and the beam portion, and the fixed portion such as the fixed electrode from being broken.

It is a perspective view of the conventional acceleration sensor described in patent document 1. FIG. It is a perspective view of the conventional acceleration sensor indicated in patent documents 3. (A), (b) is a block diagram for demonstrating Example 1 of the capacitive acceleration sensor based on this invention, (a) is a top view, (b) is AA of (a). It is sectional drawing. (A), (b) is a block diagram for demonstrating Example 2 of the capacitive acceleration sensor based on this invention, (a) is a top view, (b) is AA of (a). It is sectional drawing. It is a block diagram for demonstrating Example 3 of the capacitive acceleration sensor which concerns on this invention. It is a block diagram for demonstrating Example 4 of the capacitive acceleration sensor which concerns on this invention. It is a block diagram for demonstrating Example 5 of the capacitive acceleration sensor which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIGS. 3A and 3B are configuration diagrams for explaining the first embodiment of the capacitive acceleration sensor according to the present invention. FIG. 3A is a top view and FIG. 3B is a diagram. It is AA sectional drawing of 3 (a).

  The capacitive acceleration sensor according to the first embodiment includes a displaceable weight body 36 disposed on a substrate 35 in a separated state, a movable electrode 34 provided on the weight body 36, and the movable electrode. , And a fixed electrode 33 disposed opposite to the electrode 34, and detects an acceleration based on a displacement of the weight body 36 for a change in capacitance between the electrodes 33, 34. Further, both the weight body 36 and the substrate 35 are provided with complementary locking means for restricting the displacement of the weight body 36 in the horizontal direction and potential fixing means for fixing the potential to the complementary locking means. It is a thing. Reference numeral 39 denotes a fixing member provided on the substrate 35.

  The complementary locking means includes one through hole 38 provided in the weight body 36 and one locking member (stopper) 37 provided on the substrate 35 and inserted into the through hole 38. The locking member 37 is erected on the substrate 35. In order to increase the rigidity, all the upper surfaces of the locking members 37 can have a height corresponding to the thickness of the weight body, or can be equal to or higher than the height corresponding to the thickness of the weight body. is there.

  The weight body 36 is attached to support members 31a and 31b provided on the substrate 35 via beam members 32a and 32b. The potential fixing means includes a locking member 37 and support members 31a and 31b. The conductive wire 51 is wired to the substrate 35. The conductive wire 51 electrically connects the locking member 37 and the weight body 36 so that the potential of the locking member 37 is the same as that of the weight body 36. . By doing in this way, the Coulomb force which acts between the locking member 37 and the weight body 36 can be canceled out, and the decrease in sensitivity due to the Coulomb force can be prevented.

  The through-hole 38 is provided in the central portion of the weight body 36, and the cross-sectional shape thereof may be an ellipse, but a circle is optimal. The locking member 37 is preferably a rod-shaped member, and the conductive wire 51 is wired in the rod-shaped member as described above. Further, the through hole provided in the weight body may be a hole or groove that does not penetrate, and the place to be provided may be provided in a portion other than the central portion of the weight body 36. The distance between the locking member and the weight body is preferably equal to or less than the distance between the movable electrode and the fixed electrode from the viewpoint of avoiding collision with the fixed electrode as much as possible due to the horizontal displacement of the movable electrode.

  Further, the movable electrode 34 constituting the capacitive acceleration sensor is a plurality of thin plate-like comb movable electrodes, and the fixed electrode 33 is a plurality of thin plate-like combs disposed respectively facing the comb-like movable electrodes. It is a mold-fixed electrode.

  Further, the comb movable electrode is provided on both sides in the Y axis direction with respect to the X axis direction which is the displacement direction of the weight body 36, and the comb fixed electrode is disposed to face the comb movable electrode. Has been. Further, as shown in the figure, the comb-shaped fixed electrode is composed of a pair of comb-shaped fixed electrodes that sandwich the comb-shaped movable electrode.

  Further, the beam members 32 a and 32 b are spring members that are displaced with an elastic force with respect to the horizontal displacement of the weight body 36.

  With such a configuration, the weight body is provided with a through hole, and a locking member that is inserted into the through hole is provided on the substrate so as to regulate the horizontal displacement of the weight body. The contact area is the same even in the case of acceleration, and the impact stress applied to the movable part and the fixed part is reduced compared to the conventional one, and the movable part such as the weight, movable electrode, and beam member is fixed to the fixed electrode. The destruction of the part can be prevented. Further, since the locking member has a height corresponding to the thickness of the weight body or a height higher than that, it can be a stopper means having higher rigidity than the stopper described in Patent Document 5 described above.

  That is, in the capacitive acceleration sensor, when an acceleration exceeding the allowable displacement amount of the movable part is applied, it is possible to prevent the damage due to the collision between the movable part and the fixed part, and to improve the impact resistance.

  In the conventional structure, the potential of the stopper is not fixed, and when the stopper is charged up, a Coulomb force is generated between the movable portion and the stopper. Since this Coulomb force generates an attractive force between the movable part and the stopper, it acts as a force that hinders the displacement of the movable part, causing a decrease in the sensitivity of the sensor.

  In order to solve such a problem, in Example 1, a through hole is provided in the stopper, the stopper and the movable portion are electrically connected, and the potential of the stopper is set to the same potential as that of the movable portion. Counteract the Coulomb force that works on Thereby, the problem of the sensitivity fall by Coulomb force can be solved.

  4 (a) and 4 (b) are configuration diagrams for explaining a second embodiment of the capacitive acceleration sensor according to the present invention, FIG. 4 (a) is a top view, and FIG. 4 (b) is a diagram. It is AA sectional drawing of 4 (a). Components having the same functions as those in FIG. 3 are denoted by the same reference numerals.

  In the capacitive acceleration sensor according to the second embodiment, a plurality of through holes 38a and 38b are provided in the weight body 36, and locking members 37a and 37b are inserted into the through holes 38a and 38b. . The through holes 38a and 38b are desirably provided at symmetrical positions with respect to the center of the weight body. Moreover, since the locking members 37a and 37b have a height corresponding to the thickness of the weight body 36 or a height higher than that, the stopper members 37a and 37b can be stopper means having higher rigidity than the stopper described in Patent Document 5 described above. Can be. Further, by providing a plurality of through holes 38a, 38b, it is possible to further reduce the impact stress applied to the movable part and the fixed part, and movable parts such as the weight body 36, the movable electrode 34, the beam members 32a, 32b, It is possible to prevent the fixed portion such as the fixed electrode 33 from being broken.

  Similarly to the first embodiment described above, the stopper and the movable portion are electrically connected, and the potential of the stopper is set to the same potential as that of the movable portion, thereby canceling the Coulomb force acting between the stopper and the movable portion. Thus, the problem of sensitivity reduction due to Coulomb force can be solved.

  FIG. 5 is a configuration diagram for explaining Example 3 of the capacitive acceleration sensor according to the present invention. Components having the same functions as those in FIG. 3 are denoted by the same reference numerals.

  The capacitive acceleration sensor according to the third embodiment includes a displaceable weight body 36 disposed on a substrate 35 in a separated state, a movable electrode 34 provided on the weight body 36, and the movable electrode. 34 and a fixed member 39 provided on the substrate 35 and surrounding the periphery of the weight body 36, and the capacitance change between the electrodes 33 and 34 is weighted. The acceleration is detected based on the displacement of the body 36. Further, both of the weight body 36 and the fixing member 39 are provided with complementary locking means for restricting the displacement of the weight body 36 in the horizontal direction.

  The complementary locking means separates the first protrusions 40a to 40d provided at the edge of the weight body 36, the first protrusions (projections) 40a to 40d, and the fixing member 39 from each other. The gap portions 41a to 41d are formed. The shape of the first protrusions 40a to 40d may be a cross-sectional curved shape or a circular arc shape continuously and integrally provided along the thickness direction of the weight body 36, or intermittently in the thickness direction. It may be provided with a curved cross section or a spherical cross section.

  In addition, it is desirable that the gaps 41a to 41d have an interval equal to or less than the interval between the movable electrode and the fixed electrode from the viewpoint of avoiding a collision with the fixed electrode due to the horizontal displacement of the movable electrode.

  The configuration of the movable electrode and the fixed electrode constituting the capacitive acceleration sensor is the same as that of the first embodiment described above.

  With such a configuration, a stopper having an arcuate cross section is provided at the edge of the weight body, which is a movable part. Therefore, if the movement of the movable part in the horizontal direction is restricted by this stopper, it can be viewed from any direction. Also in acceleration, the contact area is the same, and the impact stress applied to the movable part and the fixed part is smaller than that of the conventional one. The movable part such as the weight, movable electrode, and beam member, and the fixed part such as the fixed electrode Can be prevented.

  FIG. 6 is a configuration diagram for explaining a fourth embodiment of the capacitive acceleration sensor according to the present invention. Components having the same functions as those in FIG. 3 are denoted by the same reference numerals.

  Complementary locking means in the capacitive acceleration sensor according to the fourth embodiment includes second protrusions (convex parts) 42a to 42d provided at the edge of the weight body 36, and the second protrusions 42a to 42d. It consists of first groove portions (concave portions) 43a to 43d provided in the fixing member 39 so as to face the protruding portions 42a to 42d. The shape of the second protrusions 42a to 42d may be a curved cross section or a circular arc shape provided continuously and integrally along the thickness direction of the weight body 36, or intermittently in the thickness direction. It may be provided with a curved cross section or a spherical cross section. Basically, the first groove provided in the fixed portion may be complementary to the surface shape of the second protrusion described above.

  The distance between the second protrusions 42a to 42d and the first groove is not more than the distance between the movable electrode and the fixed electrode from the viewpoint of avoiding a collision with the fixed electrode due to the horizontal displacement of the movable electrode. It is desirable.

  Further, the distance between the stopper provided at the edge of the weight body 36 and the groove provided in the fixed member is made smaller than the distance between the movable part and the fixed part, and the distance between the movable part and the fixed part is set. If it is smaller than the allowable displacement amount of the movable portion, the movable portion abuts against the stopper before reaching the allowable displacement amount of the movable portion, so that further displacement is suppressed.

  In addition, the first protrusion having the circular arc shape in which the weight body is formed in the above-described third embodiment may have a size and a shape as long as it is provided via the gap. Since the 2nd projection part in example 4 becomes the shape according to the shape of the groove part provided in the fixing member, it can be made into a shape larger than the 1st projection part, and can improve a stopper function. .

  In the stopper of Example 4, the radius of the circle is 10 μm, the distance between the movable part and the fixed part is 2.5 μm, and the distance between the movable part or the fixed part and the stopper is 2 μm.

  With such a configuration, a cross-sectional arc-shaped stopper that regulates the horizontal displacement integrated with the weight body supported by the support member via the beam member is formed. In comparison, since the contact area at the time of collision is large, it is possible to prevent breakage due to stress concentration.

  FIG. 7 is a configuration diagram for explaining a fifth embodiment of the capacitive acceleration sensor according to the present invention.

  The complementary locking means in the capacitive acceleration sensor according to the fifth embodiment includes second groove portions (recess portions) 45a to 45d provided at the edge portion of the weight body 36, and the second groove portion 45a. The third projecting portions (convex portions) 44a to 44d provided on the fixing member 39 so as to oppose each other to 45d. That is, the complementary relationship is reversed in the fifth embodiment with respect to the fourth embodiment described above.

  Since the beam member supports the structure, the stress tends to concentrate on the beam member. However, since the displacement amount is suppressed with respect to the weight body via the beam member, a large impact is generated at the time of resonance or dropping. In contrast, the mechanical strength of the entire structure is improved. In addition, the mechanical strength of the stopper itself is improved because the contact area is large compared to a stopper having a conventional protruding structure.

  As mentioned above, although each Example of the capacitive acceleration sensor which concerns on this invention was described, weight bodies including what opened a through-hole in a weight body, what provided unevenness in the edge part of a weight body, etc. Since the complementary locking means for restricting the horizontal displacement is provided, it is possible to prevent the movable part such as the weight body, the movable electrode and the beam part and the fixed part such as the fixed electrode from being broken.

  In Examples 1 and 2 described above, since the locking member has a height corresponding to the thickness of the weight body, or a height higher than that, than the stopper described in Patent Document 5 described above, It becomes a stopper means with high rigidity, can cancel the Coulomb force acting between the locking member and the weight body, and can prevent a decrease in sensitivity due to the Coulomb force.

11 Stem 12 Stopper 13 Weight 14 Sensor chip 21, 22 Wafer 31a, 31b Post member 32a, 32b Beam member 33 Fixed electrode 34 Movable electrode 35 Substrate 36 Weight body 37, 37a, 37b Locking member 38, 38a, 38b Through hole 39 fixing members 40a to 40d first protrusions 41a to 41d voids 42a to 42d second protrusions 43a to 43d first grooves 45a to 45d second grooves 44a to 44d third protrusions 45a to 45d third Two grooves 51 Conductor 150 Substrate 150a, 150b, 150c, 150d Anchor portion 151, 152 Beam portion 152A Beam structure 152B Fixing portion 153, 154 Stopper portion 153a, 154a Anchor portion 153b, 154b Projection portion 156 Weight portion 157 Movable electrode 158 Fixed electrode

Claims (15)

A displaceable weight body disposed in a separated state on a substrate, a movable electrode provided on the weight body, and a fixed electrode disposed opposite to the movable electrode, and between the two electrodes In a capacitance type acceleration sensor that detects acceleration based on displacement of the weight body in a change in capacitance,
Complementary locking means for restricting horizontal displacement of the weight body and potential fixing means for fixing potential to the complementary locking means are provided on both the weight body and the substrate. Capacitance type acceleration sensor.   The complementary locking means includes a hole or a through hole provided in the weight body, and a locking member provided on the substrate and inserted into the hole or the through hole. 2. The capacitive acceleration sensor according to 1.   The capacitive acceleration sensor according to claim 2, wherein the hole or the through hole is provided around an end of the weight body.   4. The capacitive acceleration sensor according to claim 2, wherein a plurality of the holes or through holes are provided in the weight body.   The capacitive acceleration sensor according to claim 2, 3 or 4, wherein the locking member is a rod-shaped member.   The weight body is attached to a support member provided on the substrate via a beam member, and the potential fixing means is a lead wire wired to the locking member, the support member, and the substrate. 6. The capacitive acceleration sensor according to claim 1, wherein the capacitance type acceleration sensor is used. A displaceable weight body disposed on the substrate in a separated state; a movable electrode disposed on the weight body; a fixed electrode disposed opposite the movable electrode; and provided on the substrate. A capacitance-type acceleration sensor that includes a fixing member that surrounds the periphery of the weight body, and detects an acceleration based on a displacement of the weight body, based on a displacement of the weight body.
A capacitance type acceleration sensor characterized in that complementary locking means for restricting horizontal displacement of the weight body is provided on both the weight body and the fixing member.   The static complementary mechanism according to claim 7, wherein the complementary locking means includes a first protrusion provided at an edge of the weight body and a gap provided in the fixing member. Capacitive acceleration sensor.   The complementary locking means includes a second protrusion provided at an edge of the weight body, and a first groove provided in the fixing member so as to face the second protrusion. The capacitive acceleration sensor according to claim 7, wherein   The complementary locking means includes a second groove provided at an edge of the weight body and a third protrusion provided on the fixing member so as to face the second groove. The capacitive acceleration sensor according to claim 7.   11. The capacitive acceleration sensor according to claim 8, wherein the protrusion and the groove are arcuate.   The capacitive acceleration sensor according to claim 7, wherein the weight body is attached to a support member provided on the substrate via a beam member.   The movable electrode is a plurality of thin plate-like comb-shaped movable electrodes, and the fixed electrode is a plurality of thin-plate-like comb-shaped fixed electrodes respectively disposed facing the comb-shaped movable electrode. The capacitive acceleration sensor according to claim 1.   The comb movable electrode is provided on both sides in the Y axis direction with respect to the X axis direction which is a displacement direction of the weight body, and the comb fixed electrode is opposed to the comb movable electrode. The capacitive acceleration sensor according to claim 13, which is arranged.   15. The capacitive acceleration sensor according to claim 13 or 14, wherein the comb-shaped fixed electrodes are a pair of comb-shaped fixed electrodes sandwiching the comb-shaped movable electrode.

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