JP2013003034A - Electrostatic capacitance type sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic capacitance type sensor which is capable of reducing variation in output characteristics.SOLUTION: An electrostatic capacitance type sensor comprises movable electrodes 4, 5 which are movable in accordance with a physical quantity given from the outside, an upper fixed plate 2a which is disposed while being opposed to one-side surfaces of the movable electrodes 4, 5, a lower fixed plate 2b which is disposed while being opposed to other-side surfaces of the movable electrodes 4, 5, beams 6a, 6b, 7a, 7b which support the movable electrodes 4, 5 so as to freely oscillate with respect to a frame, fixed electrodes 20a, 21a disposed at a side of the upper fixed plate 2a confronted with the movable electrodes 4, 5, and a detection electrode which detects a change in electrostatic capacitance between the movable electrodes 4, 5 and the fixed electrodes 20a, 21a. A center frame 22 that is a frame in a central portion between the movable electrodes 4, 5 is not coupled partially or entirely with at least one of the upper fixed plate 2a and the lower fixed plate 2b.

Description

  The present invention relates to a capacitance type sensor that detects a physical quantity given from the outside by detecting a change in capacitance between a movable electrode and a fixed electrode.

  2. Description of the Related Art Conventionally, an acceleration sensor in which weight portions are provided on the left and right of a central frame portion is known (see Patent Document 1). This acceleration sensor is applied to the weight part by differentially detecting the change in capacitance between the movable electrode and the first and second fixed electrodes accompanying the swing of the weight part with the beam axis as the rotation axis. Detect acceleration. Patent Document 2 discloses a capacitance type mechanical quantity sensor in which a pressure sensor and an acceleration sensor are integrated. Furthermore, in Patent Document 3, the bottom surface of the support portion facing the pedestal is divided into four regions with the center of gravity of the bottom surface shape as the center, and the bottom surface of the support portion and the pedestal are divided into only one region. There is disclosed a microstructure provided with a bonding portion for bonding.

JP 2010-127648 A JP 2007-064919 A JP 2006-302943 A

  However, since the acceleration sensor disclosed in Patent Document 1 has a three-layer structure of glass / silicon / glass, there is a problem that output characteristics fluctuate due to temperature changes. That is, stress may occur at the joint due to the difference in linear expansion coefficient between glass and silicon. When stress is generated in this way, the distance between the electrodes changes due to deformation of the beam portion, and the output characteristics fluctuate.

  Patent Documents 2 and 3 do not disclose or suggest such problems. That is, the variation of the output characteristics becomes a problem when the weight portions are provided on the left and right of the central frame portion as disclosed in Patent Document 1. In the acceleration sensor having such a configuration, a mechanism for reducing fluctuations in output characteristics is required.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a capacitive sensor that can reduce fluctuations in output characteristics.

  The present invention is an electrostatic capacitance sensor, which is a movable electrode that is movable in accordance with a physical quantity given from the outside, a first glass substrate that is disposed to face one surface of the movable electrode, and the movable sensor. A second glass substrate disposed opposite to the other surface of the electrode, a beam portion for swingably supporting the movable electrode with respect to a frame portion, and the movable electrode of the first glass substrate. A fixed electrode disposed on the side, and a detection electrode for detecting a change in capacitance between the movable electrode and the fixed electrode, and a central frame portion that is a frame portion of a central portion between the movable electrodes. The part or the whole is not combined with at least one of the first glass substrate and the second glass substrate.

  The present invention is an electrostatic capacitance sensor, which is a movable electrode that is movable in accordance with a physical quantity given from the outside, a first glass substrate that is disposed to face one surface of the movable electrode, and the movable sensor. A second glass substrate disposed opposite to the other surface of the electrode, a beam portion for swingably supporting the movable electrode with respect to a frame portion, and the movable electrode of the first glass substrate. A fixed electrode disposed on the side, and a detection electrode for detecting a change in capacitance between the movable electrode and the fixed electrode, and a part of an outer peripheral frame part that is a frame part of an outer peripheral part of the movable electrode or All are not combined with at least one of the first glass substrate and the second glass substrate.

  In the present invention, an island that is not coupled to at least one of the first glass substrate and the second glass substrate is provided separately from the outer peripheral frame portion, and the island supports the beam portion. Also good.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the electrostatic capacitance type sensor which can reduce the fluctuation | variation of an output characteristic.

It is a disassembled perspective view of the acceleration sensor in 1st Embodiment. It is a bottom view of the sensor chip of the acceleration sensor in the first embodiment. It is sectional drawing of the acceleration sensor in 1st Embodiment. It is a block diagram of the conventional acceleration sensor, (a) is AA sectional drawing, (b) is a silicon layer top view, (c) is a top view of a fixed electrode, (d) is a silicon layer bottom view. It is a block diagram of the acceleration sensor in 1st Embodiment, (a) is AA sectional drawing, (b) is a top view. It is a block diagram of the acceleration sensor in 2nd Embodiment, (a) is AA sectional drawing, (b) is a bottom view. It is a block diagram of the acceleration sensor in 3rd Embodiment, (a) is AA sectional drawing, (b) is a top view, (c) is a bottom view. It is a block diagram of the acceleration sensor in 4th Embodiment, (a) is AA sectional drawing, (b) is a top view. It is a block diagram of the acceleration sensor in 5th Embodiment, (a) is AA sectional drawing, (b) is a bottom view. It is a block diagram of the acceleration sensor in 6th Embodiment, (a) is AA sectional drawing, (b) is a top view, (c) is a bottom view. It is a block diagram of the acceleration sensor in 7th Embodiment, (a) is AA sectional drawing, (b) is a top view, (c) is a bottom view. It is a block diagram of the acceleration sensor in 8th Embodiment, (a) is AA sectional drawing, (b) is a top view. It is a block diagram of the acceleration sensor in 9th Embodiment, (a) is AA sectional drawing, (b) is a bottom view. It is a block diagram of the acceleration sensor in 10th Embodiment, (a) is AA sectional drawing, (b) is a top view, (c) is a bottom view. It is a block diagram of the acceleration sensor in 11th Embodiment, (a) is AA sectional drawing, (b) is a top view.

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

(First embodiment)
The acceleration sensor in the embodiment of the present invention is an improvement of the acceleration sensor disclosed in Patent Document 1. Hereinafter, the configuration of the present acceleration sensor will be described in detail with reference to the drawings.

[Configuration of acceleration sensor]
As shown in FIG. 1, the acceleration sensor in the first embodiment has a configuration in which the upper and lower surfaces of a sensor chip 1 formed of a silicon SOI substrate are sandwiched between an upper fixing plate 2a and a lower fixing plate 2b. The sensor chip 1 includes a frame portion 3 having two rectangular frames 3a and 3b and two rectangular shapes arranged in the rectangular frames 3a and 3b in a state where a gap is formed with respect to the side walls of the rectangular frames 3a and 3b. Movable electrodes 4 and 5 are provided. In addition, the sensor chip 1 is a beam that supports the movable electrode 4 so as to be swingable with respect to the frame portion 3 by connecting a substantially central portion of two opposing sides of the surface of the movable electrode 4 and a side wall portion of the rectangular frame 3a. A beam portion 7a that supports the movable electrode 5 so as to be swingable with respect to the frame portion 3 by connecting the portions 6a and 6b with the substantially center of two opposite sides of the surface of the movable electrode 5 and the side wall portion of the rectangular frame 3b. , 7b. Further, the sensor chip 1 is arranged so as to be separated from the frame part 3, the movable electrode 5, and the other detection electrodes, and the detection electrodes 8a and 8b arranged away from the frame part 3, the movable electrode 4, and the other detection electrodes. Detection electrodes 9a and 9b, and a ground electrode 10 formed on the surface of the frame portion 3 between the detection electrodes 8b and 9a. The detection electrodes 8a and 8b and the detection electrodes 9a and 9b are electrically connected to fixed electrodes 20a and 20b and fixed electrodes 21a and 21b, which will be described later, respectively.

  In the present embodiment, as shown in FIG. 2, between the detection electrode 8a and the detection electrode 8b, between the detection electrode 9a and the detection electrode 9b, between the detection electrodes 8a and 8b and the frame part 3, and between the detection electrodes 9a and 9b and the frame part 3 A gap is formed between the detection electrodes 8a and 8b and the movable electrode 4 and between the detection electrodes 9a and 9b and the movable electrode 5. According to such a configuration, since each detection electrode is electrically insulated, parasitic capacitance of each detection electrode and crosstalk between detection electrodes can be reduced, and highly accurate capacitance detection can be performed. become. The gaps and the rectangular frames 3a and 3b are isolated from the outside and sealed.

  On one side having a straight line connecting the beam portions 6a and 6b on the back surface of the movable electrode 4 as a boundary line, as shown in FIG. 2, recesses 11a, 11b, and 11c as first recesses defined by the reinforcing member 16 are provided. , 11d are formed. Further, a concave portion 12 as a second concave portion is formed on the other side having a straight line connecting the beam portions 6 a and 6 b on the back surface of the movable electrode 4 as a boundary line. Similarly, on one side having a straight line connecting the beam portions 7a and 7b on the back surface of the movable electrode 5 as a boundary line, as shown in FIG. 2, the concave portions 13a and 13a as first concave portions partitioned by the reinforcing member 16 are provided. 13b, 13c, 13d are formed. Further, a concave portion 14 as a second concave portion is formed on the other side having a straight line connecting the beam portions 7a and 7b on the back surface of the movable electrode 5 as a boundary line.

  In the present embodiment, the first recess and the second recess are formed as separate bodies. For example, the first recess and the second recess are formed by enlarging the first recess to the other side beyond the boundary line. May be formed integrally. Further, the shape of the first recess is not limited to the triangular shape shown in FIG. 2, and may be the same rectangular shape as the second recess. Further, as shown in FIG. 3, the position where the second concave portion is formed is such that the detection sensitivity in the x direction and the z direction is equivalent because the angle θ formed by the center of gravity O of the movable electrode and the beam portion is 45 degrees. There is no particular limitation as long as it is a position. If the second recess is formed on the side farther from the boundary line, the rotational moment becomes larger, so that the detection sensitivity of the acceleration sensor can be increased.

  As shown in FIG. 3 (only the movable electrode 4 is shown in FIG. 3) on the surfaces of the movable electrodes 4 and 5 facing the upper fixed plate 2a and the lower fixed plate 2b, a plurality of silicon or silicon oxide films are formed. Projecting portions 15a to 15g are formed. By forming such protrusions 15a to 15g, even when a large acceleration exceeding the measurement range is applied to the movable electrodes 4 and 5, the movable electrodes 4 and 5 are opposed to the upper fixed plate 2a and the lower portion. Since it does not directly collide with the fixed plate 2b, the sensor chip 1 can be prevented from being damaged. In the present embodiment, the protrusions are formed on the surfaces of the movable electrodes 4 and 5 that face the upper fixed plate 2a and the lower fixed plate 2b, but they face the movable electrodes 4 and 5 of the upper fixed plate 2a and the lower fixed plate 2b. Similar protrusions may be formed on the surface.

  The upper fixed plate 2a is formed of a glass substrate, and fixed electrodes 20a and 20b are provided on the surface facing the movable electrode 4 with a straight line connecting the beam portion 6a and the beam portion 6b as a boundary line. Similarly, on the surface side of the upper fixed plate 2a facing the movable electrode 5, fixed electrodes 21a and 21b are provided with a straight line connecting the beam portion 7a and the beam portion 7b as a boundary line. Through holes 22a to 22e are formed at positions facing the detection electrodes 8a, 8b, 9a and 9b and the ground electrode 10 of the upper fixed plate 2a, and the fixed electrodes 20a and 20b and the fixed electrodes are formed through the through holes 22a to 22e. The outputs of the detection electrodes 8a and 8b, the detection electrodes 9a and 9b, and the ground electrode 10 connected to 21a and 21b, respectively, are taken out. The lower fixed plate 2b is formed of a glass substrate, and fixed electrodes 20a and 20b made of an aluminum alloy or the like are spaced apart from the back surfaces of the movable electrodes 4 and 5 on the side facing the back surfaces of the movable electrodes 4 and 5. , 21a, 21b are provided with adhesion preventing films 23a, 23b made of the same material. By providing such adhesion preventing films 23a and 23b, it is possible to prevent the movable electrodes 4 and 5 from adhering to the lower fixed plate 2b during operation, and the movable electrodes 4 and 5 and the lower fixed plate 2b can be connected even during an excessive impact. Impact can be mitigated because there is no direct contact.

[Operation of acceleration sensor]
Next, the operation of the acceleration sensor in the first embodiment will be described. This acceleration sensor performs a self-test as described below and detects acceleration in the x and z directions.

[Self-test]
When the movable electrode 4 is operated, an attractive force is generated between the fixed electrode 20 a or the fixed electrode 20 b and the movable electrode 4. Similarly, when the movable electrode 5 is operated, an attractive force is generated between the fixed electrode 21 a or the fixed electrode 21 b and the movable electrode 5. A similar operation check may be performed by generating a suction force between the adhesion preventing films 23a, 23b and the movable electrodes 4, 5. As a result, the capacitance between the fixed electrodes 20a, 20b and the movable electrode 4 and between the fixed electrodes 21a, 21b and the movable electrode 5 changes due to the swinging of the movable electrodes 4, 5, so that the acceleration sensor is normal. It can be confirmed whether or not it works.

[Acceleration detection in x direction]
When acceleration in the x direction is applied to the movable electrode 4, the capacitances C1 and C2 between the movable electrode 4 and the fixed electrodes 20a and 20b are expressed by the following equations (1) and (2), respectively. In Equations (1) and (2), the parameter C0 indicates the capacitance between the movable electrode 4 and the fixed electrodes 20a and 20b when no acceleration in the x direction is applied to the movable electrode 4.

C1 = C0−ΔC (1)
C2 = C0 + ΔC (2)
Similarly, when an acceleration in the x direction is applied to the movable electrode 5, the capacitances C3 and C4 between the movable electrode 5 and the fixed electrodes 21a and 21b are expressed by the following equations (3) and (4), respectively. Become. In Equations (3) and (4), the parameter C0 indicates the capacitance between the movable electrode 5 and the fixed electrodes 21a and 21b when no acceleration in the x direction is applied to the movable electrode 5.

C3 = C0−ΔC (3)
C4 = C0 + ΔC (4)
Accordingly, the electrostatic capacitances C1 to C4 are detected via the detection electrodes 8a and 8b and the detection electrodes 9a and 9b, and the difference value CA (= C1−C2) between the electrostatic capacitance C1 and the electrostatic capacitance C2 using ASIC or the like. ), A difference value CB (= C3−C4) between the capacitance C3 and the capacitance C4. Then, the sum (± 4ΔC) of the calculated difference value CA and difference value CB is output as an X output. Thereby, the acceleration in the x direction applied to the movable electrodes 4 and 5 can be detected from the change in capacitance.

[Acceleration detection in z direction]
When acceleration in the z direction is applied to the movable electrode 4, the capacitances C1 and C2 between the movable electrode 4 and the fixed electrodes 20a and 20b are expressed by the following equations (5) and (6), respectively. In Equations (5) and (6), the parameter C0 indicates the capacitance between the movable electrode 4 and the fixed electrodes 20a and 20b when no acceleration in the z direction is applied to the movable electrode 4.

C1 = C0 + ΔC (5)
C2 = C0−ΔC (6)
Similarly, when an acceleration in the z direction is applied to the movable electrode 5, the capacitances C3 and C4 between the movable electrode 5 and the fixed electrodes 21a and 21b are expressed by the following equations (7) and (8), respectively. Become. In Equations (7) and (8), the parameter C0 indicates the capacitance between the movable electrode 5 and the fixed electrodes 21a and 21b when no acceleration in the z direction is applied to the movable electrode 5.

C3 = C0−ΔC (7)
C4 = C0 + ΔC (8)
Accordingly, the electrostatic capacitances C1 to C4 are detected via the detection electrodes 8a and 8b and the detection electrodes 9a and 9b, and the difference value CA (= C1−C2) between the electrostatic capacitance C1 and the electrostatic capacitance C2 using ASIC or the like. ), A difference value CB (= C3−C4) between the capacitance C3 and the capacitance C4. Then, the sum (± 4ΔC) of the calculated difference value CA and difference value CB is output as a Z output. Thereby, the acceleration in the z direction applied to the movable electrodes 4 and 5 can be detected from the change in capacitance.

[Reduction of fluctuations in output characteristics]
Next, a configuration for reducing fluctuations in output characteristics will be described.

  4A and 4B are configuration diagrams of a conventional acceleration sensor, where FIG. 4A is a cross-sectional view taken along the line AA, FIG. 4B is a top view of the silicon layer, and FIG. (D) is a bottom view of the silicon layer. As described above, there has been a problem that the output characteristics fluctuate due to a temperature change. That is, stress may be generated in the joint portion 30 due to a difference in linear expansion coefficient between glass and silicon. When the stress is generated in this way, the distance between the electrodes changes due to the deformation of the beam portions 6a, 6b, 7a, 7b, and the output characteristics fluctuate.

  Therefore, in the present embodiment, as shown in FIG. 5, a gap 32a is provided in the upper portion of the central frame portion 32 so that the central frame portion 32 is not coupled to the upper fixing plate 2a. The center frame portion 32 is a frame at the center portion between the movable electrodes 4 and 5. Thereby, the stress which generate | occur | produces in the coupling | bond part of the center frame part 32 can be made small. 5 illustrates a configuration in which the entire upper portion of the central frame portion 32 is not coupled to the upper fixing plate 2a, but a configuration in which a part of the upper portion of the central frame portion 32 is not coupled to the upper fixing plate 2a is employed. May be.

  As described above, in the acceleration sensor according to the first embodiment, the center frame portion 32 is not coupled to the upper fixing plate 2a. Thereby, since the stress which generate | occur | produces in the coupling | bond part of the center frame part 32 can be made small, it becomes possible to reduce the fluctuation | variation of an output characteristic.

(Second Embodiment)
Hereinafter, only differences between the second embodiment and the first embodiment will be described.

  6A and 6B are configuration diagrams of the acceleration sensor according to the second embodiment, in which FIG. 6A is a cross-sectional view taken along the line AA, and FIG. 6B is a bottom view. As shown in this figure, in the second embodiment, a gap 32b is provided in the lower portion of the central frame portion 32 so that the central frame portion 32 is not coupled to the lower fixing plate 2b. Thereby, the stress which generate | occur | produces in the coupling | bond part of the center frame part 32 can be made small. 6 illustrates a configuration in which the entire lower portion of the central frame portion 32 is not coupled to the lower fixing plate 2b, but a configuration in which a portion of the lower portion of the central frame portion 32 is not coupled to the lower fixing plate 2b is employed. May be.

  As described above, in the acceleration sensor according to the second embodiment, the center frame portion 32 is not coupled to the lower fixing plate 2b. Thereby, since the stress which generate | occur | produces in the coupling | bond part of the center frame part 32 can be made small, it becomes possible to reduce the fluctuation | variation of an output characteristic.

(Third embodiment)
Hereinafter, only differences of the third embodiment from the first and second embodiments will be described.

  7A and 7B are configuration diagrams of the acceleration sensor according to the third embodiment, in which FIG. 7A is a cross-sectional view taken along line AA, FIG. 7B is a top view, and FIG. 7C is a bottom view. As shown in this figure, in the third embodiment, gaps 32a and 32b are provided in the upper and lower portions of the central frame portion 32 so that the central frame portion 32 is not coupled to the upper fixing plate 2a and the lower fixing plate 2b. . Thereby, the stress which generate | occur | produces in the coupling | bond part of the center frame part 32 can be made small.

  As described above, in the acceleration sensor according to the third embodiment, the center frame portion 32 is not coupled to the upper fixing plate 2a and the lower fixing plate 2b. Thereby, since the stress which generate | occur | produces in the coupling | bond part of the center frame part 32 can be made small, it becomes possible to reduce the fluctuation | variation of an output characteristic.

(Fourth embodiment)
Hereinafter, only differences of the fourth embodiment from the first to third embodiments will be described.

  8A and 8B are configuration diagrams of the acceleration sensor according to the fourth embodiment, where FIG. 8A is a cross-sectional view taken along the line AA, and FIG. 8B is a top view. As shown in this figure, in the fourth embodiment, a gap 31a is provided in the upper part of the outer peripheral frame part 31 so that a part of the outer peripheral frame part 31 is not coupled to the upper fixing plate 2a. The outer peripheral frame portion 31 is a frame of the outer peripheral portion of the movable electrode 4 and is a frame located at the root of the beam portion 6a. Further, a gap 33a is provided in the upper portion of the outer peripheral frame portion 33 so that the entire outer peripheral frame portion 33 is not coupled to the upper fixing plate 2a. The outer peripheral frame portion 33 is a frame of the outer peripheral portion of the movable electrode 5 and is a frame located at the root of the beam portion 7b. Thereby, the stress which generate | occur | produces in the coupling | bond part of the outer periphery flame | frame parts 31 and 33 can be made small.

  8 illustrates a configuration in which a part of the upper portion of the outer peripheral frame portion 31 is not coupled to the upper fixing plate 2a, but a configuration in which the entire upper portion of the outer peripheral frame portion 31 is not coupled to the upper fixing plate 2a is employed. May be. Thus, if it is set as the structure which does not couple | bond together, airtightness cannot be ensured, but generation | occurrence | production stress can be made smaller.

  8 illustrates a configuration in which the entire upper portion of the outer peripheral frame portion 33 is not coupled to the upper fixing plate 2a, but a configuration in which a part of the upper portion of the outer peripheral frame portion 33 is not coupled to the upper fixing plate 2a is employed. May be. Such a configuration in which a part is not coupled reduces the effect of reducing the generated stress, but can ensure airtightness.

  As described above, in the acceleration sensor according to the fourth embodiment, the outer peripheral frame portions 31 and 33 are not coupled to the upper fixing plate 2a. Thereby, since the stress which generate | occur | produces in the coupling | bond part of the outer periphery frame parts 31 and 33 can be made small, it becomes possible to reduce the fluctuation | variation of an output characteristic.

(Fifth embodiment)
Hereinafter, only differences of the fifth embodiment from the first to fourth embodiments will be described.

  9A and 9B are configuration diagrams of an acceleration sensor according to the fifth embodiment, in which FIG. 9A is a cross-sectional view taken along the line AA, and FIG. 9B is a bottom view. As shown in this figure, in the fifth embodiment, a gap 31b is provided at the lower portion of the outer peripheral frame portion 31 so that a part of the outer peripheral frame portion 31 is not coupled to the lower fixing plate 2b. Further, a gap 33b is provided at the lower part of the outer peripheral frame part 33 so that the entire outer peripheral frame part 33 is not coupled to the lower fixing plate 2b. Thereby, the stress which generate | occur | produces in the coupling | bond part of the outer periphery flame | frame parts 31 and 33 can be made small.

  9 illustrates a configuration in which a part of the lower portion of the outer peripheral frame portion 31 is not coupled to the lower fixing plate 2b, but a configuration in which the entire lower portion of the outer peripheral frame portion 31 is not coupled to the lower fixing plate 2b is employed. May be. Further, the configuration in which the entire lower portion of the outer peripheral frame portion 33 is not coupled to the lower fixing plate 2b is illustrated, but a configuration in which a part of the lower portion of the outer peripheral frame portion 33 is not coupled to the lower fixing plate 2b may be employed. .

  As described above, in the acceleration sensor according to the fifth embodiment, the outer peripheral frame portions 31 and 33 are not coupled to the lower fixing plate 2b. Thereby, since the stress which generate | occur | produces in the coupling | bond part of the outer periphery frame parts 31 and 33 can be made small, it becomes possible to reduce the fluctuation | variation of an output characteristic.

(Sixth embodiment)
Hereinafter, only differences of the sixth embodiment from the first to fifth embodiments will be described.

  10A and 10B are configuration diagrams of an acceleration sensor according to the sixth embodiment, in which FIG. 10A is a cross-sectional view taken along line AA, FIG. 10B is a top view, and FIG. 10C is a bottom view. As shown in this figure, in the sixth embodiment, gaps 31a and 31b are provided in the upper and lower portions of the outer peripheral frame portion 31, so that the outer peripheral frame portion 31 is not coupled to the upper fixing plate 2a and the lower fixing plate 2b. . Further, gaps 33a and 33b are provided at the upper and lower portions of the outer peripheral frame portion 33 so that the outer peripheral frame portion 33 is not coupled to the upper fixing plate 2a and the lower fixing plate 2b. Thereby, the stress which generate | occur | produces in the coupling | bond part of the outer periphery flame | frame parts 31 and 33 can be made small.

  As described above, in the acceleration sensor according to the sixth embodiment, the outer peripheral frame portions 31 and 33 are not coupled to the upper fixing plate 2a and the lower fixing plate 2b. Thereby, since the stress which generate | occur | produces in the coupling | bond part of the outer periphery frame parts 31 and 33 can be made small, it becomes possible to reduce the fluctuation | variation of an output characteristic.

(Seventh embodiment)
Hereinafter, only differences of the seventh embodiment from the first to sixth embodiments will be described.

  11A and 11B are configuration diagrams of an acceleration sensor according to the seventh embodiment, where FIG. 11A is a cross-sectional view taken along the line AA, FIG. 11B is a top view, and FIG. 11C is a bottom view. As shown in this figure, in the seventh embodiment, gaps 32a and 32b are provided in the upper and lower portions of the central frame portion 32 so that the central frame portion 32 is not coupled to the upper fixing plate 2a and the lower fixing plate 2b. . Further, gaps 31a and 31b are provided at the upper and lower portions of the outer peripheral frame portion 31, so that the outer peripheral frame portion 31 is not coupled to the upper fixing plate 2a and the lower fixing plate 2b. Further, gaps 33a and 33b are provided at the upper and lower portions of the outer peripheral frame portion 33 so that the outer peripheral frame portion 33 is not coupled to the upper fixing plate 2a and the lower fixing plate 2b. Thereby, the stress which generate | occur | produces in the coupling | bond part of the center frame part 32 and the outer periphery frame parts 31 and 33 can be made small.

  As described above, in the acceleration sensor according to the seventh embodiment, the central frame portion 32 and the outer peripheral frame portions 31 and 33 are not coupled to the upper fixing plate 2a and the lower fixing plate 2b. Thereby, since the stress which generate | occur | produces in the coupling | bond part of the center frame part 32 and the outer periphery frame parts 31 and 33 can be made small, it becomes possible to reduce the fluctuation | variation of an output characteristic.

(Eighth embodiment)
Hereinafter, only the differences of the eighth embodiment from the first to seventh embodiments will be described.

  12A and 12B are configuration diagrams of an acceleration sensor according to the eighth embodiment, where FIG. 12A is a cross-sectional view taken along the line AA, and FIG. 12B is a top view. As shown in this figure, in the eighth embodiment, islands 34 and 35 are provided separately from the outer peripheral frame portions 31 and 33, and the islands 34 and 35 support the beam portions 6a and 7b. Gaps 34a and 35a are formed in the upper portions of the islands 34 and 35, and the islands 34 and 35 and the upper fixing plate 2a are not coupled.

  As described above, in the acceleration sensor according to the eighth embodiment, the islands 34 and 35 that are not coupled to the upper fixing plate 2a are provided separately from the outer peripheral frame portions 31 and 33, and the islands 34 and 35 have the beam portions 6a and 7b. I try to support it. As a result, stress generated in the vicinity of the beam portions 6a and 7b can be reduced, so that fluctuations in output characteristics can be reduced. Further, since it is not necessary to provide a gap in the outer peripheral frames 31 and 33, airtightness can be ensured.

(Ninth embodiment)
Hereinafter, only the differences of the ninth embodiment from the first to eighth embodiments will be described.

  FIG. 13: is a block diagram of the acceleration sensor in 9th Embodiment, (a) is AA sectional drawing, (b) is a bottom view. As shown in this figure, in the ninth embodiment, islands 34 and 35 are provided separately from the outer peripheral frame portions 31 and 33, and the islands 34 and 35 support the beam portions 6a and 7b. Gaps 34b and 35b are formed below the islands 34 and 35 so that the islands 34 and 35 are not coupled to the lower fixing plate 2b.

  As described above, in the acceleration sensor according to the ninth embodiment, the islands 34 and 35 that are not coupled to the lower fixing plate 2b are provided separately from the outer peripheral frame portions 31 and 33, and the islands 34 and 35 have the beam portions 6a and 7b. I try to support it. As a result, stress generated in the vicinity of the beam portions 6a and 7b can be reduced, so that fluctuations in output characteristics can be reduced. Further, since it is not necessary to provide a gap in the outer peripheral frames 31 and 33, airtightness can be ensured.

(10th Embodiment)
Hereinafter, only differences between the tenth embodiment and the first to ninth embodiments will be described.

  14A and 14B are configuration diagrams of an acceleration sensor according to the tenth embodiment, wherein FIG. 14A is a cross-sectional view taken along the line AA, FIG. 14B is a top view, and FIG. 14C is a bottom view. As shown in this figure, in the tenth embodiment, islands 34 and 35 are provided separately from the outer peripheral frame portions 31 and 33, and the islands 34 and 35 support the beam portions 6a and 7b. Gaps 34a and 35a are formed in the upper portions of the islands 34 and 35, and the islands 34 and 35 and the upper fixing plate 2a are not coupled. Further, gaps 34b and 35b are formed below the islands 34 and 35 so that the islands 34 and 35 are not coupled to the lower fixing plate 2b.

  As described above, in the acceleration sensor according to the tenth embodiment, the islands 34 and 35 protruding from the frame portion 3 that is not coupled to the upper fixing plate 2a and the lower fixing plate 2b are provided separately from the outer peripheral frame portions 31 and 33, The islands 34 and 35 support the beam portions 6a and 7b. As a result, stress generated in the vicinity of the beam portions 6a and 7b can be reduced, so that fluctuations in output characteristics can be reduced. Further, since it is not necessary to provide a gap in the outer peripheral frames 31 and 33, airtightness can be ensured.

(Eleventh embodiment)
Hereinafter, only the difference between the eleventh embodiment and the first to tenth embodiments will be described.

  FIGS. 15A and 15B are configuration diagrams of the acceleration sensor according to the eleventh embodiment, in which FIG. 15A is a cross-sectional view taken along line AA, and FIG. 15B is a top view. As shown in this figure, in the eleventh embodiment, a gap 32a is provided in the upper part of the central frame part 32 so that the central frame part 32 is not coupled to the upper fixing plate 2a. Further, islands 34 and 35 are provided separately from the outer peripheral frame portions 31 and 33, and the islands 34 and 35 support the beam portions 6a and 7b. Gaps 34a and 35a are formed in the upper portions of the islands 34 and 35, and the islands 34 and 35 and the upper fixing plate 2a are not coupled.

  As described above, in the acceleration sensor according to the eleventh embodiment, the central frame portion 32 is not coupled to the upper fixing plate 2a. Further, islands 34 and 35 not coupled to the upper fixing plate 2a are provided separately from the outer peripheral frame portions 31 and 33 so that the islands 34 and 35 support the beam portions 6a and 7b. As a result, the stress generated in the joint portion of the central frame portion 32 can be reduced, and the stress generated in the vicinity of the beam portions 6a and 7b can be reduced, so that fluctuations in output characteristics can be reduced. It becomes possible. Further, since it is not necessary to provide a gap in the outer peripheral frames 31 and 33, airtightness can be ensured.

  In addition, although preferred embodiment was described above, this invention is not limited to the said embodiment, A various deformation | transformation is possible. For example, in FIG. 15, the gaps 32 a, 34 a, 35 a are provided at the upper part of the central frame part 32 and the upper parts of the islands 34, 35, but the gaps are provided at the lower part of the central frame part 32 and the lower parts of the islands 34, 35. It is also possible.

  Although an acceleration sensor is illustrated here as an example of a capacitive sensor, the present invention is not limited to this. That is, the present invention can be similarly applied to a pressure sensor that detects a pressure by a change in resistance.

2a Upper fixed plate (first glass substrate)
2b Lower fixing plate (second glass substrate)
4, 5 Movable electrode 3 Frame part 31, 33 Outer frame part 32 Central frame part 6a, 6b, 7a, 7b Beam part 8a, 8b, 9a, 9b Detection electrode 20a, 20b, 21a, 21b Fixed electrode 34, 35 Island

Claims (3)

A movable electrode movable according to a physical quantity given from the outside;
A first glass substrate disposed opposite to one surface of the movable electrode;
A second glass substrate disposed opposite to the other surface of the movable electrode;
A beam portion that swingably supports the movable electrode with respect to the frame portion;
A fixed electrode disposed on a side of the first glass substrate facing the movable electrode;
A detection electrode for detecting a change in capacitance between the movable electrode and the fixed electrode;
A part or all of a central frame part, which is a frame part of the central part between the movable electrodes, is not coupled to at least one of the first glass substrate and the second glass substrate. Capacitance type sensor. A movable electrode movable according to a physical quantity given from the outside;
A first glass substrate disposed opposite to one surface of the movable electrode;
A second glass substrate disposed opposite to the other surface of the movable electrode;
A beam portion that swingably supports the movable electrode with respect to the frame portion;
A fixed electrode disposed on a side of the first glass substrate facing the movable electrode;
A detection electrode for detecting a change in capacitance between the movable electrode and the fixed electrode;
A part or all of the outer peripheral frame portion which is a frame portion of the outer peripheral portion of the movable electrode is not coupled to at least one of the first glass substrate and the second glass substrate. Capacitive sensor.   The island that is not combined with at least one of the first glass substrate and the second glass substrate is provided separately from the outer peripheral frame portion, and the island supports the beam portion. 3. The capacitive sensor according to 1 or 2.

Images