JPH11160349A - Acceleration sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a function for measuring azimuth and to miniaturize a sensor by providing a Hall element at a weight part or a pedestal. SOLUTION: A movable electrode 3 is provided on the lower surface of a weight part 12 and a fixed electrode 4 is provided on the upper surface of a pedestal 2. Acceleration is detected by detecting the distortion of a beam part 11 due to the application of the acceleration to a weight part 12 as a change of capacitance between the movable electrode 3 and the electrode 4. Also, an azimuth is detected by a Hall element 5 being formed on the weight part 12. The Hall element 5 is formed on the upper surface of the weight part 12 and hence is formed on a vertical line for the movable electrode 3 and the electrode 4 of an acceleration sensor, thus eliminating the need for separately forming the acceleration sensor and the Hall element, and also forming the Hall element 5 with only an area for constituting the conventional acceleration sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention comprises a support, a beam supported by the support, a weight connected to the beam, and a pedestal joined to the support. The acceleration sensor has a function of measuring acceleration and azimuth, and is used for a navigation system or the like.

[0002]

2. Description of the Related Art Conventionally, this kind of acceleration sensor, for example,
As shown in FIG. 7, the capacitive acceleration sensor has a beam structure in which a beam 11 is supported on a substrate 7 by a support 10 via a pedestal 2 and a weight 12 is connected to the beam 11. Is provided. The movable electrode 3 is provided on the lower surface of the weight portion 12, and the fixed electrode 4 is provided on the upper surface of the pedestal 2. The acceleration is detected by detecting the distortion of the beam 11 due to the acceleration applied to the weight 12 as a change in the capacitance between the movable electrode 3 and the fixed electrode 4. As the acceleration sensor, a piezoresistive acceleration sensor using a piezoresistor may be used instead of the above-described capacitance type acceleration sensor.

A Hall element 5 is provided on a substrate 7 via a pedestal 6. The Hall element 5 is a cross-shaped element having two input terminals and two output terminals. The Hall element 5 detects a direction by a Hall voltage generated between the output terminals when a voltage is applied to the input terminals. That is, when a voltage is applied to the input terminal and the current I flows,
When a magnetic field is vertically applied to the Hall element 5, a Hall voltage V is generated between the output terminals. Now, assuming that the thickness of the Hall element is d, the Hall voltage V is represented by V = H × I × B / d. Here, H is a Hall coefficient and is a constant peculiar to the material. As is clear from this equation, the smaller d is,
A highly sensitive Hall element can be obtained. Hall element 5
Indium antimony, gallium arsenide, or the like is used as the material for.

[0004]

However, in the above-described acceleration sensor, since the acceleration sensor and the Hall element are provided as separate modules on the substrate 7, the occupied area is large and the size is small. Was difficult.

[0005] The present invention has been made in view of the above points, and an object of the present invention is to provide a small-sized acceleration sensor having a function of azimuth measurement.

[0006]

According to the first aspect of the present invention,
In an acceleration sensor having a support, a beam supported by the support, a weight connected to the beam, and a pedestal joined to the support, the acceleration sensor includes: In which a hall element is provided.

According to a second aspect of the present invention, in the first aspect of the present invention, in the piezoresistive acceleration sensor in which a piezo element is formed on the beam portion, a hall element is provided on a pedestal. Things.

According to a third aspect of the present invention, in the first aspect of the present invention, in the capacitive acceleration sensor having a fixed electrode and a movable electrode, the fixed electrode is provided on an upper surface of a pedestal, and the movable electrode is weighted. And a Hall element is provided on the upper surface of the weight portion.

According to a fourth aspect of the present invention, there is provided a capacitance type acceleration sensor having a fixed electrode and a movable electrode, wherein the fixed electrode is provided on an upper surface of a base and the movable electrode is weighted. And an upper pedestal provided on an upper portion of the support portion, and a hall element provided on the upper pedestal.

According to a fifth aspect of the present invention, in the capacitance type acceleration sensor having a fixed electrode and a movable electrode according to the first aspect of the present invention, the movable electrode is provided on an upper surface of a weight portion and the support portion is provided. An upper pedestal is provided at the top of the
The fixed electrode is provided on a lower surface of the upper pedestal, and a Hall element is provided on an upper surface of the upper pedestal.

According to a sixth aspect of the present invention, in the first aspect of the present invention, in a capacitance type acceleration sensor having a fixed electrode and a movable electrode, a Hall element is provided on a lower surface of a weight portion, and the movable electrode is weighted. An upper pedestal is provided on the upper portion of the support portion, and the fixed electrode is provided on a lower surface of the upper pedestal.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view illustrating a schematic configuration of an acceleration sensor according to an example of an embodiment of the present invention. In this embodiment, a silicon chip 1 having a beam structure in which a weight portion 12 is supported by a support portion 10 and a beam portion 11 on a glass pedestal 2 is provided. The beam structure is
The beam portion 11 and the weight portion 12 are formed by digging a silicon chip to form a concave portion. The movable electrode 3 is provided on the lower surface of the weight portion 12, and the fixed electrode 4 is provided on the upper surface of the pedestal 2. The acceleration is detected by detecting the distortion of the beam 11 caused by the acceleration applied to the weight 12 as a change in the capacitance between the movable electrode 3 and the fixed electrode 4.

Here, the Hall element 5 is provided on the upper surface of the weight portion 12 by forming a material such as indium antimony by a method such as vapor deposition or sputtering. The Hall element 5 is a cross-shaped element having two input terminals 51 and two output terminals 52 as shown in the top view of FIG. The Hall element 5 has an input terminal 5
The azimuth is detected by the Hall voltage generated between the output terminals 52 when a voltage is applied to 1, and the principle of this detection is as described in the prior art.

In the present embodiment, the acceleration is
2 is detected as a change in the capacitance between the movable electrode 3 and the fixed electrode 4, thereby detecting the acceleration. The direction is the weight 12
It is detected by the Hall element 5 formed above.

According to the present embodiment, the Hall element 5 is formed on the upper surface of the weight portion 12 and is formed on a line perpendicular to the movable electrode 3 and the fixed electrode 4 of the acceleration sensor. It is not necessary to separately form the acceleration sensor and the Hall element on the substrate, and the Hall element 5 can be formed only with the area that has constituted the conventional acceleration sensor.

FIG. 3 is a schematic sectional view showing a schematic configuration of an acceleration sensor according to another embodiment of the present invention. In the present embodiment, a piezoresistive sensor is used as the acceleration sensor, and the piezoresistive element 8 is formed on the upper surface of the beam portion 11 to constitute the acceleration sensor. The Hall element 5 is formed on the upper surface of the pedestal 2.

According to this embodiment, similarly to the above-described embodiment, the Hall element 5 is replaced by the piezoresistive element 8 of the acceleration sensor.
Since it is formed on a vertical line with respect to the formed acceleration sensor, it is not necessary to separately form the acceleration sensor and the Hall element on the substrate, and only the area that constitutes the conventional acceleration sensor is eliminated. Thus, the Hall element 5 can be formed.

FIG. 4 is a schematic sectional view showing a schematic configuration of an acceleration sensor according to another embodiment of the present invention. In the acceleration sensor according to the embodiment shown in FIG.
A glass upper pedestal 21 having a concave portion is provided thereon, and the Hall element 5 is formed on the upper surface of the upper pedestal 21.

According to the present embodiment, similarly to the above-described embodiment, the Hall element 5 is formed on a vertical line with respect to the movable electrode 3 and the fixed electrode 4 of the acceleration sensor. It is not necessary to separately form the acceleration sensor and the Hall element, and the Hall element 5 can be formed only with the area that has constituted the conventional acceleration sensor.

FIG. 5 is a schematic sectional view showing a schematic configuration of an acceleration sensor according to another embodiment of the present invention. In the acceleration sensor according to the embodiment shown in FIG.
Is formed on the upper surface of the weight portion 12, and the fixed electrode 4 is
1 is formed on the lower surface.

According to the present embodiment, similarly to the above-described embodiment, the Hall element 5 is formed on a vertical line with respect to the movable electrode 3 and the fixed electrode 4 of the acceleration sensor. It is not necessary to separately form the acceleration sensor and the Hall element, and the Hall element 5 can be formed only with the area that has constituted the conventional acceleration sensor.

FIG. 6 is a schematic sectional view showing a schematic configuration of an acceleration sensor according to another embodiment of the present invention. In the acceleration sensor according to the embodiment shown in FIG. It has a configuration formed on the lower surface.

According to this embodiment, the same effects as those of the above-described embodiment can be obtained.

[0024]

As described above, according to the first to sixth aspects of the present invention, the Hall element is used for a pressure measuring element such as a movable electrode, a fixed electrode or a piezoresistive element of an acceleration sensor. Since it is formed on a vertical line, it is not necessary to separately form an acceleration sensor and a Hall element on a substrate, and a Hall element can be formed only with the area that constitutes a conventional acceleration sensor. Thus, a small acceleration sensor having a function of measuring the direction can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a schematic configuration of an acceleration sensor according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of an upper surface of the acceleration sensor.

FIG. 3 is a schematic cross-sectional view illustrating a schematic configuration of an acceleration sensor according to another embodiment of the present invention.

FIG. 4 is a schematic sectional view showing a schematic configuration of an acceleration sensor according to another embodiment of the present invention.

FIG. 5 is a schematic sectional view showing a schematic configuration of an acceleration sensor according to another embodiment of the present invention.

FIG. 6 is a schematic sectional view showing a schematic configuration of an acceleration sensor according to another embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view illustrating a schematic configuration of an acceleration sensor according to a conventional example.

[Description of Signs] 1 Silicon chip 2 Glass pedestal 3 Movable electrode 4 Fixed electrode 5 Hall element 8 Piezoresistive element 10 Support section 11 Beam section 12 Weight section 21 Upper pedestal 51 Input terminal 52 Output terminal

Claims (6)

[Claims] 1. An acceleration sensor comprising a support, a beam supported by the support, a weight connected to the beam, and a pedestal joined to the support. An acceleration sensor, wherein a hall element is provided on a weight or a pedestal. 2. The acceleration sensor according to claim 1, wherein in the piezoresistive acceleration sensor having a piezo element formed on the beam portion, a Hall element is provided on a pedestal. 3. A capacitance type acceleration sensor having a fixed electrode and a movable electrode, wherein the fixed electrode is provided on an upper surface of a pedestal, the movable electrode is provided on a lower surface of a weight portion, and a Hall element is provided on an upper surface of the weight portion. The acceleration sensor according to claim 1, wherein the acceleration sensor is provided. 4. A capacitance type acceleration sensor having a fixed electrode and a movable electrode, wherein the fixed electrode is provided on an upper surface of a pedestal, and the movable electrode is provided on a lower surface of a weight portion.
The acceleration sensor according to claim 1, wherein an upper pedestal is provided on the upper portion of the support, and a hall element is provided on the upper pedestal. 5. A capacitance type acceleration sensor having a fixed electrode and a movable electrode, wherein the movable electrode is provided on an upper surface of a weight portion, an upper pedestal is provided on an upper portion of the support portion, and the fixed electrode is mounted on the upper portion. The acceleration sensor according to claim 1, wherein the acceleration sensor is provided on a lower surface of the pedestal, and the Hall element is provided on an upper surface of the upper pedestal. 6. A capacitance type acceleration sensor having a fixed electrode and a movable electrode, wherein a Hall element is provided on a lower surface of the weight portion, the movable electrode is provided on an upper surface of the weight portion, and an upper pedestal is provided above the support portion. The acceleration sensor according to claim 1, wherein the fixed electrode is provided on a lower surface of the upper pedestal.