JP2007017284A - Sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To certainly protect a movable member and a stopper from damage, in a sensor that displaceably supports the plate-like movable member on a plate-like substrate, detects displacement of the surface direction of the movable member, and thus detects physical quantity such as acceleration and angular velocity. <P>SOLUTION: In disposing a stopper 36 for limiting over displacement for preventing the damage, a through hole 35 is drilled in its thickness direction in the movable member 24, the stopper 36 is erected so as to be loosely inserted into the through hole 35 from a support substrate while a micro gap is kept from the hole in non-contact manner, and the center of gravity of the movable member 24 is matched with that of the stopper 36. Therefore, the displacement from various directions is two-dimensionally and stably stopped in a balanced manner, and the movable member 24 and the stopper 36 can be certainly protected from the damage. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is suitably implemented as a so-called comb-shaped electrostatic capacitance sensor using MEMS (Micro Electro Mechanical System) technology, and supports a plate-like movable member on a plate-like substrate so as to be displaceable. The present invention relates to a sensor that detects physical quantities such as acceleration and angular velocity by detecting displacement in the surface direction of a movable member.

  FIG. 11 is a front view showing the structure of a typical prior art acceleration sensor 1. In this acceleration sensor 1, a main substrate 1 made of a flat silicon substrate is roughly carved into a shape as shown in FIG. 11 by etching using a MEMS technique, and is made of a flat glass substrate. It is configured by being laminated on a support substrate. Main substrate 1 is bonded to the support substrate by, for example, anodic bonding. At substantially the center of the main substrate 1, the movable member 2 is supported by the support substrate by beams 3 and 4 whose left and right end surfaces can be bent and deformed so that the movable member 2 can be displaced in the left and right direction in FIG. ing.

  From the support substrate, a pair of support pillars 5 and 6 are erected on one end side of the movable member 2, and the support pillars 5 and 6 support the other end side of the movable member 2. Beams 7 and 8 are extended. Electrodes 9 and 10 are connected to the support beams 7 and 8 so as to have a comb shape. Correspondingly, comb-like electrodes 11 and 12 are provided on both end surfaces of the movable member 2 in the vertical direction in FIG. Therefore, when the movable member 2 is displaced in the left-right direction, the capacitance between the electrodes 9 and 10 and the electrodes 11 and 12 changes, and acceleration can be detected.

  In the acceleration sensor 1 configured as described above, the vertical displacement of the movable member 2 in FIG. 11 is suppressed by the shape of the beams 3 and 4. On the other hand, although it is freely displaceable in the left-right direction of FIG. 11 which is the detection direction, stoppers 13 and 14 are erected from the support substrate in order to limit excessive displacement. These stoppers 13 and 14 are provided on the other end side of the movable member 2 so as not to obstruct the electrodes 9, 10; 11, 12. For example, the distance between the electrodes 9 and 10 and the electrodes 11 and 12 is 10 to 15 μm, and the distance between the stoppers 13 and 14 and the movable member 2 is 8 to 10 μm. The electrodes 9 and 10 and the electrodes 11 and 12 are not in contact with each other and are not damaged.

On the other hand, Patent Document 1 prevents excessive displacement with a through hole and a rod for loosely inserting the through hole. Similarly, the through hole is formed at the tip of a weight.
Japanese Patent No. 2513080

  In each of the above-described conventional techniques, since the stopper is formed at a position deviating from the center of gravity position, the movement of the movable member and the stopper does not coincide with the external force, and the movable member allows the stopper. There is a problem that the movable member and the stopper are damaged due to collision exceeding the impact force that can be generated. For example, in FIG. 11, the portions 15 and 16 on the other end side of the movable member 2 from the stoppers 13 and 14 are broken down, and the tips of the stoppers 13 and 14 are broken down.

  An object of the present invention is to provide a sensor capable of preventing damage to a movable member and a stopper in advance even when displacement is two-dimensionally from various directions.

  The sensor according to the present invention is a sensor in which a plate-like movable member is movably supported on a plate-like substrate, and a physical quantity is detected by detecting displacement in the surface direction of the movable member. A through-hole is formed in the thickness direction of the substrate, and an over-displacement limiting stopper that is erected from the substrate and loosely inserts into the through-hole is provided, and the center of gravity of the movable member and the center of gravity of the stopper are made to coincide with each other. It is characterized by that.

  According to the above configuration, the plate-like movable member is movably supported on the plate-like substrate, and a physical quantity such as acceleration or angular velocity is detected by detecting the displacement in the surface direction of the movable member. In order to provide an excessive displacement limiting stopper for preventing damage to the sensor, a through hole is formed in the movable member in the thickness direction, and the stopper is formed in the through hole from the substrate. Stand up so that it can be inserted loosely while maintaining a small gap that does not touch.

  Further, the center of gravity of the movable member and the center of gravity of the stopper are matched. For example, the through hole is formed so that the center of the through hole coincides with the center of gravity of the movable member, and the center of the stopper is erected so as to coincide with the center of the through hole. In addition, when the through hole is drilled at a position symmetric with respect to the center of gravity of the movable member, the stopper is also loosely inserted in each through hole, and the center of the stopper stands so as to coincide with the center of the through hole. Set up.

  Therefore, since the stopper limits the excessive displacement of the movable member in a state where the center of gravity coincides with the movable member, the displacement from various directions is balanced in a two-dimensional manner (surface direction of the substrate and the movable member) in a stable manner. It can stop and can protect a movable member and a stopper reliably.

  In the sensor of the present invention, another substrate is provided with the movable member interposed therebetween, and in the sensor that houses the movable member in an internal space between the substrates, the tip of the stopper is attached to the other substrate. It extends so that it may contact.

  According to said structure, since a stopper supports the external load of the thickness direction of a board | substrate and movable members, such as the pressure at the time of molding, it can protect so that an upper and lower board | substrate may not be damaged.

  Furthermore, the sensor of the present invention is characterized in that a buffer spring is provided on the outer periphery of the stopper or the inner periphery of the through hole.

  According to said structure, the impact between this movable member and a stopper can be relieve | moderated also with respect to the sudden displacement of a movable member.

  As described above, the sensor of the present invention supports a plate-like movable member on a plate-like substrate so as to be displaceable, and detects physical displacement such as acceleration and angular velocity by detecting displacement in the surface direction of the movable member. In the sensor to be detected, when providing a stopper for restricting excessive displacement to prevent breakage of the sensor, the movable member is provided with a through hole in the thickness direction, and the stopper is formed from the substrate. While standing upright so that the gap which does not contact the inside of the through hole is maintained, the center of gravity of the movable member and the center of gravity of the stopper are matched.

  Therefore, since the stopper limits the excessive displacement of the movable member in a state where the center of gravity coincides with the movable member, the displacement from various directions in a two-dimensional manner can be stably stopped in a balanced manner. It can be surely protected.

[Embodiment 1]
FIG. 1 is a front view showing the structure of the acceleration sensor 21 according to the first embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the section line II-II in FIG. In this acceleration sensor 21, a main substrate 22 made of a flat silicon substrate is roughly carved into a shape as shown in FIG. 1 by etching using a MEMS technique, and a support made of a flat glass substrate. It is configured by being laminated on the substrate 23. The main substrate 22 is bonded to the support substrate 23 by, for example, anodic bonding. A semiconductor other than silicon can be used for the main substrate 22. At substantially the center of the main substrate 22, the movable member 24 is formed by rectangular wave-like beams 25 and 26 whose left and right end surfaces can be bent and deformed so that the movable member 24 can be displaced in the left and right directions in FIGS. It is supported by the support substrate 23.

  From the support substrate 23, a pair of support columns 27 and 28 are erected on one end side of the movable member 24, and from the support columns 27 and 28 toward the other end side of the movable member 24, Support beams 29 and 30 are extended. Electrodes 31 and 32 are connected to the support beams 29 and 30 so as to have a comb shape. Correspondingly, comb-like electrodes 33 and 34 are provided on both end surfaces of the movable member 24 in the vertical direction in FIG. Therefore, when the movable member 24 is displaced in the left-right direction, the capacitance between the electrodes 31 and 32 and the electrodes 33 and 34 changes, and acceleration can be detected. The above points are the same as those of the acceleration sensor 1 shown in FIG.

  It should be noted that in the acceleration sensor 21 according to the present invention, the through hole 35 is formed in the thickness direction of the movable member 24, and the excessive displacement is limited by loosely inserting the inside of the through hole 35 from the support substrate 23. The stopper 36 is erected, and the center of gravity of both is made to coincide with the center 37 of the stopper 36. Further, the displacement of the movable member 24 in the vertical direction in FIG. 1 is suppressed by the shapes of the beams 25 and 26. For example, the distance between the electrodes 31 and 32 and the electrodes 33 and 34 is 10 to 15 μm, and the distance between the outer peripheral surface of the stopper 36 and the inner peripheral surface of the through hole 35 is 8 to 10 μm. 36 is loosely inserted while maintaining a minute gap that does not contact the inside of the through hole 35, and excessive displacement is prevented by the stopper 36 so that the electrodes 31, 32 and the electrodes 33, 34 are not in contact with each other and are not damaged. It is configured.

  By configuring in this way, the stopper 36 limits the excessive displacement of the movable member 24 at the center of gravity of the movable member 24, so that the two directions (surface directions of the substrates 22, 23 and the movable member 24) are various in two dimensions. Can be stably stopped in a balanced manner, and the movable member 24 and the stopper 36 can be reliably protected.

[Embodiment 2]
FIG. 3 is a front view showing the structure of the acceleration sensor 41 according to the second embodiment of the present invention. The acceleration sensor 41 is similar to the acceleration sensor 21 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that in this acceleration sensor 41, the movable member 44 carved from the main board 42 has a through hole in the thickness direction of the movable member 44 at a symmetrical position with the center of gravity 47 of the movable member 44 in between. 45a and 45b are provided, and from the support substrate 23, excessive displacement limiting stoppers 46a and 46b that are loosely inserted in the through holes 45a and 45b are provided, respectively, and two stoppers 46a and 46b are provided. Is the center of gravity 47 of the movable member 44. The space | interval of the outer peripheral surface of stopper 46a, 46b and the internal peripheral surface of through-hole 45a, 45b is 8-10 micrometers, for example.

  By configuring in this way, the stoppers 46a and 46b limit the excessive displacement of the movable member 44 in a state where the center of gravity coincides with the movable member 44. Therefore, the displacement from various directions in a two-dimensional manner is well balanced. It is possible to stop stably and reliably protect the movable member 44 and the stoppers 46a and 46b.

[Embodiment 3]
FIG. 4 is a cross-sectional view showing the structure of an acceleration sensor 51 according to the third embodiment of the present invention. The acceleration sensor 51 is also similar to the acceleration sensor 21 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that in this acceleration sensor 51, another substrate 53 is provided with the main substrate 21 sandwiched from the support substrate 23, and the movable member 24 is placed in the internal space 24 between the substrates 23 and 53. Corresponding to this, the stopper 56 is extended so that the tip of the stopper 56 comes into contact with the other substrate 53. The substrate 53 is also made of a glass substrate, and is bonded to the main substrate 22 by anodic bonding. The substrate 53 is formed with through wiring 59 for connecting the electrodes 31 and 32 and the external connection electrode on the front surface side.

  Accordingly, the stopper 56 supports the external loads in the thickness direction of the substrates 23 and 53 and the movable member 24 such as the pressure at the time of molding as shown in FIG. 5, so that the upper and lower substrates 23 and 53 are protected from being damaged. be able to.

[Embodiment 4]
FIGS. 6-8 is a front view which shows the structure of a part of acceleration sensor 61,71,81 based on the 4th Embodiment of this invention. 6 to 8 show the periphery of the through hole 65 of the movable members 64, 74, and 84. The through hole 65 and the stopper 66 are rectangular in common between the acceleration sensors 61, 71, and 81. Formed. In the acceleration sensors 61 and 71, a rectangular wave-shaped buffer spring 67 is interposed between the movable members 64 and 74 and the stopper 66. The buffer spring 67 is attached to the inner peripheral surface of the through hole 65 in the acceleration sensor 61, and is attached to the outer peripheral surface of the stopper 66 in the acceleration sensor 71.

  On the other hand, in the acceleration sensor 81, an arch-shaped buffer spring 87 is interposed between the movable member 84 and the stopper 66. In FIG. 8, the buffer spring 87 is attached to the inner peripheral surface of the through hole 65, but may be attached to the outer peripheral surface of the stopper 66. In providing the buffer springs 67 and 87, the through hole 65 and the stopper 66 are not limited to a rectangle, and may have a curved surface as long as the buffer springs 67 and 87 can be attached.

  With this configuration, it is possible to reduce the impact between the movable members 64, 74, 84 and the stopper 66 even when the movable members 64, 74, 84 are steeply displaced. In addition, by providing the buffer springs 67 and 87 on the stopper 66 side, even if the buffer springs 67 and 87 are broken, the weight of the movable members 74 and 84 is not changed, and the influence on the sensitivity is small.

[Embodiment 5]
FIG. 9 is a front view showing the structure of an angular velocity sensor 101 according to the fifth embodiment of the present invention, and FIG. 10 is a cross-sectional view taken along the section line IX-IX in FIG. The angular velocity sensor 101 is similar to the acceleration sensor 51 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. In this angular acceleration sensor 101 as well, the mechanism for suppressing the excessive displacement of the movable member 104 by the stopper 36 is the same.

  For angular acceleration detection, the movable member 104 passes through the center of gravity of the movable member 104 and is a bar-like beam 105 disposed on a center line 107 that equally divides the weight of the upper side and the lower side in FIG. , 106 are supported by the support substrate 23. The beams 105 and 106 can be bent and twisted, and can be displaced in the vertical direction of FIG. 9 as indicated by reference numeral 108 in FIG. 9 and in the thickness direction of the movable member 104 as indicated by reference numeral 109 in FIG. In addition, displacement around the rod-like beams 105 and 106 is possible.

  In this angular acceleration sensor 101, the electrodes 31, 32; 33, 34 are used for bias vibration of the movable member 104. For this reason, detection electrodes are respectively provided on the opposing surfaces of the movable member 104 and the other substrate 53. 111, 112 are formed. Due to the angular velocity applied from the outside, the distance between the detection electrodes 111 and 112 changes, and the capacitance changes, and the angular velocity can be detected. The driving electrodes 31 and 32 are drawn out by the through wiring 59, and the detection electrode 112 is drawn out by the through wiring 110.

  With this configuration, the angular velocity can be detected.

  Although Patent Document 1 describes that a plurality of through holes for preventing excessive displacement may be formed with a weight, it is described that the centers of gravity of the movable member and the stopper are matched. There is no suggestion.

It is a front view which shows the structure of the acceleration sensor which concerns on the 1st Embodiment of this invention. It is sectional drawing seen from the cut surface line II-II of FIG. It is a front view which shows the structure of the acceleration sensor which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the structure of the acceleration sensor which concerns on the 3rd Embodiment of this invention. It is sectional drawing which shows the mode at the time of the mold of the acceleration sensor shown in FIG. It is a front view which shows the structure of a part of acceleration sensor which concerns on the 4th Embodiment of this invention. It is a front view which shows the structure of a part of acceleration sensor which concerns on the 4th Embodiment of this invention. It is a front view which shows the structure of a part of acceleration sensor which concerns on the 4th Embodiment of this invention. It is a front view which shows the structure of the angular velocity sensor which concerns on the 5th Embodiment of this invention. It is sectional drawing seen from the cut surface line IX-IX of FIG. It is a front view which shows the structure of the typical prior art acceleration sensor.

Explanation of symbols

21, 41, 51, 61, 71, 81 Acceleration sensor 22, 42 Main substrate 23 Support substrate 24, 44, 64, 74, 84, 104 Movable members 25, 26; 105, 106 Beams 27, 28 Support columns 29, 30 Support beam 31, 32; 33, 34 Electrode 35; 45a, 45b; 65 Through hole 36; 46a, 46b; 56; 66 Stopper 37 Center 47 Center of gravity 53 Another substrate 59, 110 Through wiring 67, 87 Buffer spring 101 Angular velocity sensor 107 Center line 111, 112 Detection electrode

Claims (3)

In a sensor that supports a plate-like movable member on a plate-like substrate so as to be displaceable, and detects a physical quantity by detecting displacement in the surface direction of the movable member.
Drilling a through hole in the thickness direction of the movable member,
Provided with a stopper for restricting excessive displacement that is erected from the substrate and loosely inserts in the through hole;
A sensor characterized in that a center of gravity of the movable member and a center of gravity of a stopper are matched. In the sensor for providing another substrate sandwiching the movable member, and storing the movable member in an internal space between the substrates,
The sensor according to claim 1, wherein a tip end of the stopper is extended so as to come into contact with the another substrate.   The sensor according to claim 1, wherein a buffer spring is provided on an outer periphery of the stopper or an inner periphery of the through hole.

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