JPH06241793A - Inclination sensor - Google Patents

Abstract

PURPOSE:To provide an inclination sensor capable of precisely detecting the inclination in all directions without being affected by the temperature change and little affected by noises. CONSTITUTION:Multiple fixed electrodes 7 arranged in different directions are formed on a base 1. A recess 11 is formed on one face of a base 2 by etching processing, a soft film 21 is formed on the recess 11, a mobile electrode forming section 22 is formed at the center section of the soft film 21, and multiple soft support films 9 are formed around the electrode forming section 22. A mobile electrode 8 is formed at the electrode forming section 22. A space section 13 is formed between the bottom face 15 of the recess 11 and the mobile electrode 8, and the base 2 is integrally mounted on the base 1 with the mobile electrode 8 side facing downward. The mobile electrode 8 is suspended by the soft support films 9. When an inclination sensor is inclined, the capacity between the fixed electrode 7 and the mobile electrode 8 is changed by the inclination change of the electrode due to the inclination, and the inclination of the sensor can be precisely detected in all the directions.

Description

Detailed Description of the Invention

[0001]

This invention relates to FA (Factory Automati).
on) a tilt sensor used for posture detection of equipment, automobiles, and various work vehicles.

[0002]

2. Description of the Related Art FIG. 5 shows a tilt sensor using a conventional piezoresistive element. The tilt sensor 5 is formed by processing, for example, the base 1 to form a weight 3 on the center side, and mounting and fixing, for example, a silicon base 2 on the upper side of the base 1, and by mounting the silicon base 2 on the upper surface of the silicon base 2. A plurality of piezoresistive elements 6 are formed. When the sensor is tilted, the direction of gravity of the weight 3 changes, and bending stress is generated in the silicon base 2. This change in stress is transmitted to the piezoresistive element 6, and the resistance of the resistive element changes. The inclination of the sensor is detected by utilizing this resistance change.

[0003]

However, the inclination sensor 5 using the piezoresistive element 6 has a problem that the characteristic of the sensor changes with temperature because the resistance of the resistive element 6 changes with temperature. There is a troublesome problem that a complicated temperature guarantee circuit must be provided to cancel the characteristic change due to. Further, since the element is a resistor, there is a problem that power consumption is large.

Further, various types of capacitance type tilt sensors (not shown) utilizing electrostatic capacitance have been proposed. By using these capacitive tilt sensors, it is possible to eliminate the influence of temperature changes and reduce power consumption. However, these capacitive tilt sensors have a simple structure and can detect tilts in all directions with high accuracy. Since there is nothing to do and the detection electrode is directly fixed to the base, there is a problem in that it is easily affected by the nozzle caused by vibration during traveling of a truck or the like and cannot be accurately detected.

The present invention has been made in order to solve the above-mentioned conventional problems, and an object thereof is to detect an inclination in all directions with high accuracy without being affected by temperature change, and to reduce the influence of noise. The object is to provide a small tilt sensor.

[0006]

In order to achieve the above object, the present invention is constructed as follows. That is, the tilt sensor of the present invention has a pair of bases that are arranged to face each other with a gap therebetween, and a fixed electrode is formed on the surface of the base on one side, and a gap is formed on the opposite side of this fixed electrode. A movable electrode is provided through the movable electrode, and the movable electrode is fixed to the base on the other side by suspending the periphery of the movable electrode with a plurality of flexible supporting films. It is characterized in that it is formed by a plurality of distributed electrode patterns, and the other side electrode is formed by a single electrode pattern that faces the whole of the plurality of electrode patterns.

It is also a characteristic feature of the present invention that the flexible support film and the base on which the movable electrode is suspended by the flexible support film are made of a silicon-based material.

[0008]

When the tilt sensor tilts, the movable electrodes suspended by the plurality of flexible supporting films change and tilt more than the tilt of the base,
A capacitance change occurs between the fixed electrode and the movable electrode through a gap. At this time, the capacitance between the electrodes on the one side and the electrodes on the other side of the plurality of electrode patterns distributed in different directions changes according to the direction and size of the inclination of the movable electrode, and based on this capacitance change, the inclination changes. Accurately detects the inclination and size of the sensor in all directions.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the tilt sensor of this embodiment.

In the figure, a fixed electrode 7 is formed on the center of the upper surface of a base 1 made of glass or the like (may be a silicon material). As shown in FIG. 3B, the fixed electrode 7 is composed of a plurality of (eight in the embodiment) circular electrodes 7, and the eight electrodes 7 are diagonally arranged on the same circumference. , Are formed by electrode patterns distributed in different directions. Further, a connection electrode 14 and a signal extracting electrode 19 are provided in a conductive state on the peripheral edge side of the base 1, and the fixed electrode 7 is connected to the signal extracting electrode 18 of the same electrode 7 by a conductor pattern 23. ing.

Further, as shown in FIG. 1, a silicon base 2 having a recess 11 is placed on the upper side of the base 1 with the recess 11 on the lower side. (A), conductor patterns 17 for connecting to the connection electrodes 14 of the fixed electrode 7 are formed on both edge sides. The conductor pattern 17 and the connecting electrode 14 are made of, for example, a low-melting point metal. By heating and melting this metal to fuse and connect the connecting electrode 14 and the conductor pattern 17, the base 1 and the base 1 The base 2 is integrated.

Further, as shown in FIGS. 1 and 3 (a), a flexible film 21 is formed in the recess 11 of the base 2.
A circular electrode forming portion 22 is provided in the central portion of the flexible film 21, and a plurality of electrode patterns of the fixed electrode 7 are provided on the electrode forming portion 22, that is, on the surface facing the fixed electrode 7. A single movable electrode 8 having a circular shape facing each other is formed via a gap 16. In addition, as shown in FIG.
A plurality of the movable electrodes 8 are hung around the
Individual) thin string-like flexible supporting films 9 are formed, and conductor patterns 24 are formed on the surfaces of the plurality of thin string-like flexible supporting films 9.

Next, a method of manufacturing the tilt sensor of this embodiment will be described with reference to the drawings. In the method of manufacturing this inclination sensor, the bonding technology and etching technology of the semiconductor manufacturing technology are used. First, on one side surface of the silicon base 2 shown in FIG. 4A, silicon as shown in FIG. The concave portion 11 is formed by anisotropic etching or the like. On the bottom surface 15 of this recess 11,
The sacrifice layer film 12 is formed as shown in FIG. Then
As shown in FIG. 4D, a flexible film 21 of a nitride film or a polysilicon film is formed on the bottom surface 15 of the recess 11 so as to cover the sacrifice layer film 12. A movable electrode forming portion 22 is formed in the central portion of the flexible film 21, and around the movable electrode forming portion 22, (a) of FIG.
A plurality (eight in the embodiment) of thin string-shaped flexible support films 9 for suspending the movable electrode 8 as shown in FIG. Next, as shown in FIG. 4E, the movable electrode 8 is formed on the movable electrode forming portion 22, and the conductor pattern 17 is formed on the peripheral edge side of the base 2.
To form. Then, the sacrificial layer film 12 is etched to form a space 13. When the movable electrode 8 is placed on the lower side of the base 2 as shown in FIG. 4F, the movable electrode 8 is suspended by a plurality of flexible supporting films 9 (eight in the embodiment).

On the upper surface of the base 1 shown in FIG. 4G, a plurality of (8 in the embodiment) fixed electrodes 7 shown in FIG. 4H and FIG. 3B are connected. The electrode 14 and the signal extraction electrode 19 are formed, the base 2 of FIG. 4 (f) is placed on the base 1, and the connection electrode 14 and the conductor pattern 17 are heat-treated and melted. As shown in (i), the base 1 and the base 2 are fused and integrated.

When the tilt sensor of this embodiment is tilted, as shown in FIG. 2, the movable electrode 8 hung on the flexible supporting film 9 has a slacking direction and size depending on its weight. Instead, the tilt of the movable electrode 8 becomes larger than the tilt of the base of the tilt sensor. As a result, a large capacitance change occurs between the fixed electrode 7 and each movable electrode 8, and the capacitance change is accurately processed by, for example, a computer or the like to accurately detect the tilt direction and tilt size of the tilt sensor.

According to the present embodiment, since the inclination is detected by utilizing the change of the electrostatic capacitance, it is not affected by the temperature as in the case of the conventional piezoresistive element, and the complicated temperature is prevented. Since the security circuit is unnecessary and the resistance element is not used, the power consumption can be reduced.

Further, the movable electrode 8 is suspended by a thin string-shaped flexible supporting film 9 to form an electrode pattern in which a plurality of fixed electrodes 7 are distributed in different directions, and the flexible supporting film depending on the weight of the movable electrode 8 is formed. Since the inclination is increased according to the degree of slack in 9, the change in capacitance becomes large, and the direction and magnitude of the inclination of the sensor can be accurately detected.

Further, since the space portion 13 is formed between the bottom surface 15 of the recess 11 of the base 2 and the movable electrode 8, for example, the air in the space portion 13 serves as a damper for noise generated by vibration of a running truck. The effect of noise can be reduced by the damper effect.

Furthermore, in this embodiment, since the joining technique and the etching technique of the semiconductor manufacturing technique are used, the manufacturing is facilitated, the cost can be reduced, and the mass production can be easily performed.

The present invention is not limited to the above-mentioned embodiment, and various embodiments can be adopted. For example, in the above embodiment, the fixed electrode 7 is used on the lower side and the movable electrode 8 is used on the upper side. However, conversely, the fixed electrode 7 may be used on the upper side and the movable electrode 8 may be used on the lower side. In this case, it is necessary to provide a relief recess on the base on the side of the lower movable electrode 8 so as not to prevent the inclined deformation of the movable electrode 8.

Further, in the above embodiment, the fixed electrode 7 is composed of eight circular electrodes, but the number of circular electrodes may be one or more, and the number is not limited. Moreover, the shape does not matter. Further, the arrangement positions do not have to be on the same circumference.

Further, in the above embodiment, the number of flexible support films 9 for suspending the movable electrode 8 is eight, but the number is not limited.

Furthermore, although the bases 1 and 2 and the flexible support film 9 are formed of a silicon-based material, if they can be easily processed by semiconductor technology and satisfy a predetermined performance (for example, flexibility). The material does not matter.

Furthermore, in the above-mentioned embodiment, the movable electrode 8 is formed with a single electrode pattern and the fixed electrode 7 is formed with a plurality of electrode patterns. On the contrary, the movable electrode 8 is formed with a plurality of electrode patterns. 7 may be configured with a single electrode pattern.

[0025]

According to the present invention, the movable electrode is hung by a plurality of flexible supporting films, and the inclination is increased depending on the degree of slack in the supporting film due to the weight of the movable electrodes. It can be detected accurately. Further, since one side of the fixed electrode and the movable electrode is formed by a plurality of electrode patterns distributed in different directions, it is possible to accurately detect all the directions of inclination of the sensor.

Further, since the inclination is detected by utilizing the capacitance change between the fixed electrode and the movable electrode, there is no influence of temperature unlike the conventional piezoresistive element, and therefore, a complicated temperature guarantee circuit is unnecessary. Since the resistance element is not used, the power consumption can be reduced.

Further, since the movable electrode is suspended by the flexible support film, for example, the noise between the moving electrode and the base is absorbed by the air as a damper to absorb the noise generated by the vibration of the running truck. The damper effect enables highly accurate inclination detection with less influence of noise.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a tilt sensor of this embodiment.

FIG. 2 is an explanatory diagram of a tilted state of a movable electrode of the tilt sensor.

FIG. 3 is an explanatory view of a main structure of the tilt sensor.

FIG. 4 is an explanatory diagram of a manufacturing process of the tilt sensor.

FIG. 5 is an explanatory diagram of a tilt sensor using a conventional piezoresistive element.

[Explanation of symbols]

 1 base 2 silicon base 7 fixed electrode 8 movable electrode 9 flexible support film 11 recess 13 space

Claims (2)

[Claims] 1. A pair of bases arranged to face each other with a gap therebetween, a fixed electrode is formed on the surface of the base on one side, and a fixed electrode is movable on the opposite side with a gap. An electrode is provided, and the movable electrode is fixed to the base on the other side by suspending the periphery of the movable electrode with a plurality of flexible supporting films, and the fixed electrode and the one side electrode of the movable electrode are distributed in different directions. A tilt sensor formed by a plurality of electrode patterns, the other side electrode being formed by a single electrode pattern facing the whole of the plurality of electrode patterns. 2. The tilt sensor according to claim 1, wherein the flexible support film and the base on which the movable electrode is suspended by the flexible support film are made of a silicon-based material.