JPH0714383U - Displacement structure of sensor - Google Patents

Abstract

(57) [Summary] [Purpose] To increase the sensitivity of the displacement part of the acceleration sensor. [Structure] An outer peripheral portion B is arranged around the central portion A. The central portion A and the outer peripheral portion B are connected by a beam-shaped flexible portion C.
The outer peripheral portion B is extended between the adjacent flexible portions C and C. The displacement electrode 4 is formed on the surface of the overhanging portion D and the surface of the outer peripheral portion B. The projecting portion D and the outer peripheral portion B, which are the operating portion Y, are floatingly supported by the beam-shaped flexible portion C, and the responsiveness thereof is improved. By providing the overhanging portion D, the operating portion Y
Spread and the electrode area increases.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a displacement part structure of a sensor used for an acceleration sensor or the like, and more particularly to a displacement part structure suitable for a capacitance type acceleration sensor that requires a wide surface electrode.

[0002]

[Prior art]

 Conventionally, various acceleration sensors such as a capacitance type sensor have been used to detect the movement of a moving body. FIG. 1 shows the operating principle of the capacitance type acceleration sensor. Further, FIG. 2 shows a conventional displacement portion structure in the capacitance type acceleration sensor.

The capacitive acceleration sensor of FIG. 1 has a Si substrate 3 (displacement substrate) provided between glass substrates 1 and 2 (fixed substrate). The Si substrate 3 has a structure in which an outer peripheral portion B which is an operating portion Y is connected to the outside of a central portion A which is a fixed portion X via a flexible portion C. Displacement electrodes 4 and 5 are formed on both surfaces of the outer peripheral portion B which is the operating portion Y. Fixed electrodes 6 and 7 are formed on the respective surfaces of the glass substrates 1 and 2 so as to face the displacement electrodes 4 and 5.

When acceleration acts on the acceleration sensor, the flexible portion C of the Si substrate 3 is twisted and the outer peripheral portion B, which is the operating portion Y, is displaced, so that the fixed electrodes 6 and 7 to the displacement electrodes 4 and 5 are displaced. The distance changes. The direction and magnitude of the acceleration acting on the acceleration sensor can be detected by the change in the capacitance with the change in the distance.

In the displacement portion of FIG. 2A, an annular diaphragm is used as the flexible portion C. An example of such a displacement portion is the displacement portion of the sensor disclosed in Japanese Patent Laid-Open No. 5-45377.

The displacement portion in FIG. 2B uses a plurality of beam-shaped flexible portions C that radially extend from the central portion A to the outside thereof and are connected to the outer peripheral portion B on the outer side. As such a displacement portion, for example, there is a displacement portion of the sensor disclosed in MP (Next Generation Sensor Conference Joint Study Group) -93-20-P81 to 83.

[0007]

[Problems to be solved by the device]

 By the way, the requirements for the displacement portion of the acceleration sensor are that the displacement portion is small and that its sensitivity is good. The sensitivity of the displacement part in the capacitance type acceleration sensor is basically governed by the following two.

One is the mechanical response of the operating part Y, and the other is the size of the surface electrode. Since the area of the surface electrode is generally controlled by the area of the displacement electrode formed on the surface of the operating portion Y, it is required to widen the operating portion Y.

In response to these requirements, in the displacement portion of FIG. 2 (A), since the flexible portion C is formed of an annular diaphragm, the mechanical response of the outer peripheral portion B which is the operating portion Y is not so good. I can't say. On the other hand, in the displacement portion of FIG. 2 (B), since the flexible portion C has a beam shape, the mechanical response of the operating portion Y is good.

However, even in the displacement portion of FIG. 2B, the flexible portion C is provided between the central portion A and the outer peripheral portion B, so that the outer peripheral portion B becomes narrower and the width of the operating portion Y becomes wider. Is inevitable to be sacrificed.

For example, in the displacement portion of FIG. 2B, it is necessary to lengthen the flexible portion C in order to enhance the mechanical responsiveness of the operating portion Y, but the size of the displacement portion is In the limited case, the longer the flexible portion C, the narrower the operating portion Y becomes.

Therefore, there is a problem in that the area of the surface electrode and the mechanical responsiveness of the operating part are not compatible with each other, and the displacement part becomes large due to the high sensitivity of the displacement part.

An object of the present invention is to provide a displacement portion structure of a sensor that can achieve both the width of the surface electrode and the mechanical responsiveness of the operating portion.

[0014]

[Means for Solving the Problems]

 The displacement part structure of the sensor of the present invention is such that the center part is located inside the frame-shaped outer peripheral part with a gap, and the center part or the outer peripheral part is displaced radially by receiving external force. The center part and the outer peripheral part are connected by a plurality of extending beam-shaped flexible parts, and the outer peripheral part projects between adjacent flexible parts, and electrodes are formed on the surface of the projecting part and the surface of the outer peripheral part. Is formed.

[0015]

[Action]

 In the displacement part structure of the sensor of the present invention, the central part and the outer peripheral part are connected by the plurality of beam-shaped flexible parts that are radially arranged, so that the mechanical response of the operating part is good. . Since the outer peripheral portion projects between the adjacent flexible portions, it is possible to widen the surface electrode despite the use of the beam-shaped flexible portion. Further, the width of the surface electrode is substantially unchanged even if the flexible portion is lengthened.

[0016]

【Example】

 An embodiment of the present invention will be described below.

FIG. 3 shows a first embodiment of the present invention.

The present embodiment is a displacement part structure of a capacitance type acceleration sensor. The acceleration sensor includes glass substrates 1 and 2 as fixed substrates which are opposed to each other with a predetermined gap, and a Si substrate 3 as a displacement substrate interposed between the glass substrates 1 and 2. .

The Si substrate 3 is a prism-shaped central portion A sandwiched and fixed between the glass substrates 1 and 2, a rectangular frame-shaped outer peripheral portion B disposed outside the central portion A and displaceable at intervals. Four beam-like flexible parts C extending outward from each surface of the central part A and connecting the central part A and the outer peripheral part B, and projecting between the outer peripheral part B and the adjacent flexible parts C, C respectively. It consists of four overhanging parts D.

In this embodiment, the central portion A is the fixed portion X, the outer peripheral portion B and the overhanging portion D are the operating portions Y, and the operating portion Y also serves as a weight. Displacement electrodes 4 and 5 are formed on both surfaces of the outer peripheral portion B and the overhanging portion D, which are the operating portions Y, and the glass substrates 1 and 2 face the displacement electrodes 4 and 5, respectively. Fixed electrodes 6 and 7 are formed, respectively.

When acceleration acts on the acceleration sensor using the present embodiment, the outer peripheral portion B and the overhanging portion D, which are the operating portion Y, are displaced according to the direction and magnitude of the acceleration.

Here, the operating portion Y is floatingly supported by the long beam-shaped flexible portion D. Therefore, the mechanical response of the operating unit Y is very good. Further, since the overhanging portion D is provided on the side of the outer peripheral portion B, the working portion Y is large and the electrode area is large despite the use of the long beam-shaped flexible portion C. Therefore, the sensitivity can be increased without increasing the size of the displacement portion.

FIG. 4 shows a second embodiment of the present invention.

This embodiment also has the displacement part structure of the capacitance type acceleration sensor. The acceleration sensor includes a fixed rectangular frame-shaped glass substrate 8 and a Si substrate 9 stacked on the glass substrate 8. , And a glass substrate 10 as a weight stacked on the Si substrate 9.

The Si substrate 9 is a prism-shaped central portion A movably arranged between the glass substrates 8 and 10, a rectangular frame-shaped outer peripheral portion B spaced apart from the central portion A, and a center. Four beam-like flexible portions C 1 extending outward from each surface of the portion A and connecting the central portion A and the outer peripheral portion B, and projecting between the outer peripheral portion B and the adjacent flexible portions C 1 and C 2, respectively. It consists of four overhangs D 1.

In the present embodiment, the central portion A is the operating portion Y, which is connected to the central portion of the glass substrate 10 as a weight. On the other hand, the outer peripheral portion B is joined to the glass substrate 8 serving as a fixed substrate to form the fixed portion X together with the four protruding portions D. Fixed electrodes 11 are formed on the upper surfaces of the outer peripheral portion B and the overhanging portion D, which are the fixed portions X. Further, a displacement electrode 12 is formed on the lower surface of the glass substrate 10 so as to face the fixed electrode 11.

When acceleration acts on the acceleration sensor using this embodiment, the glass substrate 10 as a weight is moved to the center of the operating portion Y of the Si substrate 9 depending on the direction and magnitude of the acceleration. It is displaced together with the part A.

Here, the operating part Y is floatingly supported by a long beam-shaped flexible part C. Therefore, the mechanical response of the operating unit Y is very high. Further, since the overhanging portion D is attached to the outer peripheral portion B, the operating portion Y is wide and the electrode area is large, even though the long beam-shaped flexible portion C is used. Therefore, the sensitivity can be increased without increasing the size of the displacement portion.

As described above, in the displacement part structure of the present invention, the central part A and the outer peripheral part B outside thereof are connected by the beam-shaped flexible part C, and the adjacent flexible parts C, C are connected. Since the overhanging portion D is provided on the outer peripheral portion B, the area of the surface electrode and the mechanical responsiveness of the operating portion Y can be made compatible with each other.

The overhanging portion D is a space sandwiched between the flexible portions C and C with a slight gap between the central portion A and the adjacent flexible portions C and C as in the above-described embodiment. It is convenient to dispose the electrode on almost the whole area because the surface electrode can be widened.

Further, the outer peripheral portion B is preferably thin in the horizontal direction in order to lengthen the flexible portion C. Even if the thickness of the outer peripheral portion B in the horizontal direction is reduced, the planar electrode hardly becomes narrow because of the overhanging portion D.

In the above embodiment, the beam-shaped flexible portion C is made parallel to each side of the rectangular frame-shaped outer peripheral portion B. However, as shown in FIG. The flexible portion C can be directed in the diagonal direction of the portion B, and the direction of the flexible portion C is not particularly limited.

Further, as for the shapes of the central portion A and the outer peripheral portion B, as shown in FIG. 5B, a planar shape such as a circle is also possible, and the shapes are not limited. In particular, the outer shape of the outer peripheral portion B can be freely selected without being restricted by its inner shape or the like.

In addition, although the above-described embodiment describes the capacitance type acceleration sensor, if it requires a wide surface electrode, it may be applied to another acceleration sensor or a sensor such as gravity or magnetic force. Can also be applied.

[0035]

[Effect of device]

 As described above, in the displacement portion structure of the sensor of the present invention, the central portion and the outer peripheral portion on the outer side are connected by the beam-shaped flexible portion, and the outer peripheral portion on the outer side is connected to the adjacent flexible portion. Since the space between the central portion and the outer peripheral portion is effectively utilized by the overhanging portion, the area of the surface electrode and the mechanical responsiveness of the operating portion can be made compatible. Therefore, a small and highly sensitive sensor can be constructed.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view for explaining the operation principle of an acceleration sensor.

FIG. 2 is a plan view showing a conventional displacement portion structure.

FIG. 3 is a vertical sectional view of an acceleration sensor and a plan view of a Si substrate showing an example of a displacement portion structure of the present invention.

FIG. 4 is a vertical sectional view of an acceleration sensor and a plan view of a Si substrate showing another example of the displacement portion structure of the present invention.

FIG. 5 is a plan view showing still another example of the displacement portion structure of the present invention.

[Explanation of symbols]

 1,2,8,10 Glass substrate (fixed substrate) 3,9 Si substrate (displacement substrate) 4,5,12 Displacement electrode 6,7,11 Fixed electrode A Center part B Peripheral part C Flexible part D Overhang part X fixed part Y operating part

Claims (1)

[Scope of utility model registration request] 1. A plurality of radially extending from the center to the outside so that the center is located inside the frame-shaped outer periphery with a gap and the center or the outer periphery is displaced by an external force. The central portion and the outer peripheral portion are connected by the beam-shaped flexible portion of, and the outer peripheral portion further projects between the adjacent flexible portions, and electrodes are formed on the surface of the projecting portion and the surface of the outer peripheral portion. Displacement part structure of a sensor characterized by the above.