JPH01253656A - Acceleration sensor - Google Patents

Abstract

PURPOSE:To improve detecting accuracy and to make the configuration of a sensor compact, by constituting an inertial weight which transduces acceleration into inertial pressure with mercury. CONSTITUTION:Mercury 16 is introduced to diaphragm pressure receiving surfaces 11a, 11b and 11c of diaphragms of sensor blocks 3, 4 and 5 for an axis X, an axis Y and an axis Z through paths 7, 8 and 9 and paths 10x, 10y and 10z from a mercury tank 6 beforehand. Insides 12a, 12b and 12c of glass seats 12x, 12y and 12z are filled with the mercury 16 which is introduced through the paths 10x, 10y and 10z. The component of the gravity acts as a load. Since the mercury 16 having the large load per unit area is used as an inertial weight, the inertial force applied on the pressure receiving surfaces of the pressure sensors is increased. The accuracy of sensitivity for the acceleration is increased, and an acceleration sensor 1 can be made compact.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a sensor that detects acceleration, and particularly to an acceleration sensor that converts acceleration into inertial pressure and detects acceleration based on the Harker signal. It is.

[Conventional technology]

Conventionally, acceleration sensors have been used for, for example, anti-rotation, traction, and suspension control of vehicle bodies. .

There are acceleration sensors of the type 4 type, but among these, the type that converts acceleration into pressure and detects it is, for example, 11i'i57-13 for 4 temples: (62 hours surplus). A conventional acceleration sensor of this type (:1,
This method converts acceleration into the inertia of oil that acts as an inertial weight, a pressure sensor senses this inertial pressure, and detects acceleration based on the detected value of the pressure sensor, which is advantageous in terms of reliability. It is used as J.

[Invention or problem to be solved]

By the way, as mentioned above, when oil is used as a means of converting acceleration into pressure, the load acting on the pressure sensor is small, so the sensor's value increases by 1 degree, for example, a maximum of 1 (3 to 3). In order to make it sensitive to 2G acceleration, firstly, the thickness of the strain concentrated portion of the semiconductor tire flap 13 that constitutes the pressure sensor must be made thinner, secondly, the effective diameter of the tire flap must be greatly shifted, and thirdly, the effective diameter of the tire flap must be greatly shifted. Consideration must be given to the capacity of the inertial weight.However, the first
When this method is adopted, the etching accuracy when processing the thickness of the diaphragm material is, for example, 20 ± 372
m, but it became stricter, such as 5 ± 1 μm,
Yield tends to decrease. In the second case, the outer shape of the diaphragm increases, the number of parts that can be produced from one silicon wafer decreases, and the 11i value increases. Third
In the case of When installing in a small space, there were some issues that needed to be improved, such as difficulty in placing the claws in a small space.

In addition, for the above reasons, in particular, by assembling one acceleration sensor with a plurality of pressure sensors, it is possible to simultaneously detect acceleration in two-dimensional or three-dimensional directions with each pressure sensor, while reducing the size of the acceleration sensor. The previous attempt was to create a sensor structure that would reduce product cost by 1-.

The present invention has been made in view of the following points, and its LI purpose is to improve the detection accuracy and reduce the size, and moreover, when detecting one-dimensional acceleration. Of course, it is also possible to detect acceleration in two or three dimensions.
The aim is to achieve the above objectives with a single sensor.

[Means to solve the problem]

The present invention has been made from the viewpoint that in order to achieve the object 1, it is preferable to use something instead of oil as a means for converting acceleration into pressure. The inertial weight is made of mercury, which has a specific gravity approximately 14 times greater than that of mercury and exhibits a metallic liquid state at room temperature. Specifically, it is structurally advantageous to use mercury as the inertial weight, form a tubular space to accommodate the mercury, and place a pressure-sensitive diaphragm facing this tubular space. It becomes possible to match the directionality of the acceleration and the inertial pressure of mercury applied to the pressure-receiving surface. Also,
When detecting multidimensional acceleration, the mercury storage space is branched into multidimensional axial directions, and a pressure sensitive diaphragm is arranged corresponding to each branched space.

[Effect]

According to the present invention having such a configuration, when acceleration acts on mercury, the inertial pressure of mercury corresponding to the acceleration applies to the pressure receiving surface of the pressure sensor (semiconductor diaphragm), and the acceleration is calculated based on the detected value of the pressure sensor. is detected. In the present invention, since the specific gravity of mercury is sufficiently higher than that of oil, even if the weight of the weight body is reduced to +1 J compared to the conventional one, the inertial force applied to the pressure receiving surface of the pressure sensor is increased. The sensitivity to acceleration is increased, and the temperature dependence of mercury is 1/100th that of oil, and the temperature dependence can be improved.Also, the fat swelling coefficient is 173 times lower than that of oil.
This has the advantage that there is no need to adopt a special structure that accommodates changes in volume due to temperature.

Furthermore, in the present invention, since the volume of the inertial weight is significantly reduced, even if the mercury as the inertial weight is housed in a small-diameter tubular space, it still functions sufficiently as an acceleration sensor. By adopting this, it is possible to reduce the size and weight of the sensor. And, of course, it is possible to downsize the sensor that detects acceleration in the ]-dimensional direction, and in addition, it is possible to arrange multiple pressure-sensitive diaphragms in two-dimensional and three-dimensional directions, and to inject mercury into each pressure-sensitive element. If the inertial force is applied in response to acceleration in two-dimensional or three-dimensional directions, a sensor that can simultaneously detect acceleration in two-dimensional or three-dimensional directions can be made compact and realized with an integrated structure.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1(a) is a top view of an acceleration sensor according to a first embodiment of the present invention, partially cut away and viewed from the -1 direction.
b) is a longitudinal cross-sectional view taken along line A-A in FIG. 1(a).

The acceleration sensor of this embodiment is of a type that detects acceleration in the three-dimensional directions of the X-axis, Y-axis, and X-axis, and the X-axis, Y-axis, and X-axis are illustrated by arrows, X, Y, and Z, respectively. do.

In FIGS. 1(a) and (b), 1 is an acceleration sensor, which includes a mercury tank block 2, which will be described later, an X-axis sensor block 3 that detects acceleration in the X-axis direction, and an acceleration sensor in the Y-axis direction. It is composed of a Y-axis sensor block 4 that detects acceleration in the Z-axis direction, and a Z-axis sensor block 5 that detects acceleration in the Z-axis direction.

The mercury tank block 2 has a square shape, with a mercury tank 6 formed in the center, and passages 7, 8, which form a part of a tubular mercury storage space in the X-axis direction, the Y-axis direction, and the X-axis around the tank 6.
It will be extended to 9. In addition, X-axis, Y-axis, Z-axis sensor blocks 3, 4 . ．． Each of 5 is a tubular mercury storage space (hereinafter referred to as
Mercury space) 10, semiconductor diaphragm 11. It is composed of a glass pedestal 12 and the like. Here, for convenience of explanation, mercury space 10, semiconductor diaphragm 1], glass pedestal 12
etc. will be explained by adding x, y, and z to the end of the symbol to correspond to the X-axis, Y-axis, and Z-axis sensor blocks.

X-axis sensor block 3. Y-axis sensor block 4゜Z-axis sensor block 5 is coupled to a predetermined surface of mercury tank block 2 while maintaining a sealed state, and one end of mercury space 10x of X-axis sensor block 3 communicates with passage 7 on the mercury block side. , one end of the mercury space 10y of the Y-axis sensor block 4 communicates with the passage 8, and one end of the mercury space 10z of the Z-axis sensor block 5 communicates with the passage 9.

Mercury space 1. A portion of Ox has a pressure receiving surface 1.1. Mount the semiconductor diaphragm 11 so that a is perpendicular to the X axis.
A semiconductor diaphragm 1.1. A semiconductor diaphragm llz is arranged in a part of the mercury space 10Z so as to be perpendicular to the two axes. The specifications of these diaphragms are, for example, an outer diameter of 1.511111 + an inner diameter of 1.511111.
The mercury space 10 has an inner diameter of about 1.01 111 mm at its maximum.

Also, x! The crow pedestal 12x of the ll111 sensor block 3 is the pressure receiving surface 11 of the half-centered tire flap l\11x.
The glass pedestal L2y of the Y-axis sensor block 4 is arranged so as to face the opposite side of +1.
1-y pressure receiving surface] 11) The glass pedestal 127 of the Z-axis sensor block 5 is arranged so as to face the opposite side of the pressure receiving surface 140 of the semiconductor diaphragm IZ. Also, each mercury space 10 x 1
0y, 1-Glass stand JK12x at the end of OZ
, 12y, 12z pressure receiving surfaces 1.2a, 12b.

12 c. In this way, the glass pedestal 12x
The pressure receiving surface of the conductor diaphragm llx and the pressure receiving surface of the conductor diaphragm 11. The force of mercury, which is the exact opposite of a and X 4i111, is in mercury space 1. Acts via Ox. glass pedestal 1
The force of mercury in the exact opposite direction of the Y-axis is applied to the pressure receiving surface 12b of the semiconductor diaphragm 2y and the pressure receiving surface 111 of the semiconductor diaphragm lly],
It acts through Oy. Glass pedestal 12z pressure receiving surface 1.
2c and semiconductor diaphragm]-12 pressure receiving surface 1],
A mercury force directly opposite to the Z axis acts on Q and Q through the mercury space 10z. The thickness of these glass pedestals 12 is several 1
It is thin, about 0 lz m, and deforms when the force of mercury is applied to it.

The tips of the glass pedestals 12 x, 12 y, 1-2 z have protrusions 13 x, , 13 y, 1.3
Each of z is formed, each protrusion ↑3 x + 'J,
3y, i3z are each semiconductor diaphragm 11
x + ], 1 y, ], ,1. It is fixed to the opposite surface side of z using anodic bonding or the like. With such an arrangement structure, each semiconductor diaphragm] IX
.

"IY + I J, mercury space on both sides of z", Ox
, 10y.

10z are arranged. Here, the mercury space on the side of the diaphragm facing 1 ] a , ] b , ] 1 c is defined as the first space, and the mercury space facing Daikinra 11 and other parts via the crow pedestal is defined as the second space. shall be.

Semiconductor tire flat Al 1 x, 1. ,'L y
, 1- ], z is constructed as follows.

That is, first, a silicon diaphragm is formed by etching a silicon wafer using a mask using an alkaline solution or the like. Then, on the outer periphery of this diaphragm, piezo diffusion resistors that can detect tensile strain and compressive strain when pressure is applied are implanted with ions such as 13 (boron).
Form 4 pieces each. A semiconductor diaphragm is constructed in this way, and the piezo diffusion resistance of the diaphragm is
Each wire is connected as one side of the bridge, and the wires are arranged and connected so that the potential difference at the midpoint of the bridge increases as the strain increases. The potential difference at the midpoint is the SMAR I-chip (other board)
The voltage is input to the amplifier circuit formed in iL4 through -1.15, amplified, and then taken out as an output voltage.

Reference numeral 17 denotes a vibrator having a mercury passage inside, and a pipe 7 communicates with one end or a part of the mercury passage 7, extends from this one end in the -L direction (Z-axis direction), and extends upward. A cap 19 having an air vent hole 18 is fitted to the other end of the pipe. The popular open hole 18 has a content of φ0.1 or less (
In other words, the dimensions are such that mercury does not leak due to surface tension.

Next, the operation of this embodiment will be explained.

Y-axis, Y-axis, zl1111I sensor blocks 3, 4
Tire flam pressure receiving surface 11a, 11. b,]-]
Mercury is introduced in advance from the mercury tank 6 through the passages 7, 8°9 and 1.0x, 10y, ]Oz as described above, and the crow pedestals 12x, 12y.

Inside 127 ↓ 1 passage 10 for 2a, 12b, 12c
x, 1. It is filled with 1G of mercury through OY + 10z, and the load due to the component of gravity is acting on it. Note that 1G of mercury can be easily sealed in a vacuum. Further, the acceleration sensor 1 has, for example, a bottom 11i'iP of the acceleration sensor fixed at the position to be detected.

If acceleration occurs in the detected object in such a state, for example, the acceleration in the positive direction of the X-axis component (to the left in the figure with reference to FIG. 1(b)) The pressure receiving surface 11a of the diaphragm 1-1x, mainly the material im in the mercury space 10x, receives acceleration a due to inertia and acts as an inertial pressure ma.

In addition, in the detection of acceleration in the X-axis direction, when acceleration from the opposite direction acts, mercury space 1. Inertial pressure due to mercury in Ox acts on the pressure receiving surface 12a side of the glass pedestal 12x, and this force is further applied to the diaphragm 1 via the protrusion 13x.
1. The impact force acts on the opposing surface of x. On the other hand, at this time, the mercury on the diaphragm pressure-receiving surface 11a side also moves in the same direction, and the pressure due to mercury that was acting on the diaphragm pressure-receiving surface 11a is reversed in the direction of its action, so that the mercury on the diaphragm pressure-receiving surface 11a side moves in the same direction. The acting force decreases.

Therefore, since the inertial pressure of mercury is in the opposite direction to the above-mentioned positive direction, distortion is also generated in the opposite direction, and the output signal is also opposite. In this way, it is possible to detect acceleration in two directions, the forward direction and the reverse direction.

The X-axis component and the acceleration detection of the X-axis component are also performed in the same manner as the aforementioned acceleration detection of the X-axis component.

Note that when detecting vibration acceleration, the acceleration actually changes in the form of, for example, a sine wave, as shown in FIGS. 7(a) to (d). Along with this, the load applied to the diaphragm pressure receiving surface also changes.

Therefore, the distortion generated within the diaphragm is similar to this, and the output signal also exhibits a similar waveform. - When fishing on a boat, when an external force is applied from a state where the acceleration is zero, constant, or fluctuating, a large shock wave is generated and transmitted to the object. Upon receiving this, the acceleration sensor detects the magnitude of the initial impact force,
Direction must be detected accurately without attenuation or delay. That is, a change in acceleration occurs due to the reaction of the initial impact force, and thereafter, this vibration wave continues to attenuate. Therefore, it is possible that this vibration was detected in the middle of decay.
Highly accurate control becomes impossible.

In addition, among the acceleration detection in the Z-axis, Y-axis, and Z-axis directions described above, for X, Y 1lill, that is, acceleration in the lateral force direction, the diaphragm 12
, 12y is expressed as the reference point (
If it is set as a reference signal), the magnitude relationship of acceleration when acceleration occurs can be detected. In particular, as mentioned above,
The four-way lever, where liquid pressure of mercury is applied from the back side to the glass pedestal, etc., can be detected by setting the initial value to zero by balancing the force applied to the diaphragm caused by the difference in liquid pressure between the left and right sides. You can also do it. On the other hand, the Z axis
In other words, in order to detect vertical acceleration, the state in which mercury is placed on the diaphragm, that is, the state in which a load of 1 G is applied, is used as a reference point, and from the magnitude relationship of future acceleration,
can be detected. In this case, the strain generated depending on the magnitude and direction of the acceleration received by the mercury weight located below the diaphragm is added or subtracted from the reference value, and a signal output is generated, and the Z-axis Can detect forward and reverse directions. Note that FIG. 8 shows the relationship between the sensor output voltage Vo and the acceleration G.

The above is the detection of acceleration in the three-dimensional directions of the Z-axis, Y-axis, and Z-axis. Next, transportation of the acceleration sensor of this embodiment will be explained.

As mentioned above, mercury is sealed inside the acceleration sensor body, but if this sealed mercury receives a large impact during transportation, there is a risk of destroying the diaphragm and the like. Therefore, if there is such a risk, for example, the passageway 7 on the air introduction side should be made longer than the state shown in Figure 1 (1)), for example, by extending it upward from the highest point H of the mercury. ,
5 It is set to such an extent that a space of 2 is created, and a large open hole cap is installed at the end of this passage only during transportation.
Instead, a blind plug may be fitted and the acceleration sensor may be transported upside down in this state. That is, in this way, by moving the mercury to the atmosphere introduction passage 17 side, it is possible to prevent the load of mercury from being applied to the pressure receiving surface of the diaphragm. In addition, it is necessary to house the acceleration sensor detection part in a can package or the like, and adopt a structure that prevents mercury from leaking outside due to damage to the diaphragm, for example.1 According to this embodiment, the following It can be effective.

(1) By using mercury with a specific gravity of approximately 13.6 as an inertial weight, the load per unit volume increases compared to conventional oil, so the volume of the weight applied to the diaphragm is reduced2. The acceleration sensor can be made smaller. In particular, by making the mercury storage space tubular, it is effective for making the acceleration sensor smaller and lighter.

(2) Since the acceleration sensor of this embodiment employs a three-dimensional integrated acceleration detection structure, simultaneous detection of acceleration in 11 directions can be achieved. In addition, mercury X1 that becomes a weight
The passages of the Y-axis and Z-axis are connected, and the weight of each axis (J) can be partially shared, reducing material costs and processing costs.

(3) Prepare a space in the air introduction hole in advance, and transport it until installation on the object to be detected! 7. (Hold it upside down and move the mercury into the space to reduce the negative impact on the diaphragm 13 and prevent damage.)

(4) Sharing of production technology by reusing the structure of a conventional semiconductor piezoresistive pressure transducer that converts the pressure applied to the diaphragm 13 into strain and detects it using a diffused resistance formed on the diaphragm 1. This makes it possible to reduce costs and ensure reliability.

(5) The temperature dependence of the viscosity coefficient is 1/1 compared to oil etc.
By using mercury as small as 100 mm as a weight, temperature dependence can be improved.

(6) Since mercury, which has a small volumetric expansion coefficient of 1/3 of the volume expansion coefficient, is used as a weight in accordance with changes in temperature, the center of gravity moves less and temperature dependence can be improved.

1'9. The first embodiment described above detects acceleration in three-dimensional directions, or by changing the number of blocks of the sensor flock, instead of detecting 73-dimensional acceleration, it has an integral structure and detects acceleration in xYIIIllll. Detection of acceleration in the dimensional direction, Y
, acceleration detection in the two-dimensional direction of the Z-axis can be similarly performed. Also, X axis, Y axis, Z 1lil! It is possible to detect acceleration in any one-dimensional direction.

With this integrated basic structure, acceleration in three axes can be achieved simultaneously! By combining them, it is possible to use a microcomputer or the like to calculate and determine from which direction and in what magnitude acceleration is applied.

FIG. 2 shows an embodiment (second embodiment) of the present invention applied to a sensor for detecting acceleration in the X-axis or Y direction.
In the figures, the same reference numerals as those in the embodiments in Figures (a) and (b) indicate the same or common elements.

The acceleration sensor in this embodiment basically has the same structure as the X-axis or Y-axis sensor block in the first embodiment, but the difference is that the common mercury tank block as in the first embodiment is abolished. 1. In this embodiment, the sensor body is formed by the sensor block 3', in which a tubular mercury storage space 10 is formed inside the sensor block 3' in the XJl+ (or Y-axis) direction. , by folding both ends of space 10.

With these ends facing each other, a semiconductor diaphragm is placed at one end position and a glass pedestal 12 is placed at the other end, and the tip projection 13 of the glass pedestal 12 is connected to the diaphragm in the same manner as in the first embodiment. It is joined to the surface opposite to the surface 11a. In this way, a structure is created in which mercury spaces "-" are arranged on both sides of the diaphragm strip. Its operation is similar to that of the X-axis sensor block of the 11th embodiment, and the diaphragm]-1
Pressure-receiving surface (marked by reference numeral 11a and the surface opposite to surface 11a)
The inertial pressure of the mercury core 6 acting on the mercury core 6 coincides with the direction of the acceleration.

Further, in this embodiment, an atmosphere introduction passage 17 extending in the Z-axis direction is provided in a part of the mercury passage 10. As already mentioned in the first embodiment, the atmosphere introduction passage 17 is extended north of 0.5 of the height up to the mercury level H, and when transporting the sensor, the passage 17 is plugged with a blind plug, and the sensor is turned upside down. and transport it.

FIG. 3 shows a third embodiment of the present invention, and like the second embodiment, this embodiment is also capable of detecting acceleration in the X-axis or Y-axis direction. The difference from the second embodiment is that
The inertial pressure of mercury acts only on one side 1 [a of the semiconductor diaphragm 11, the glass pedestal is omitted, and the pressure receiving surface 1 of the diaphragm 11], and the side opposite to a faces the atmosphere P.

In this embodiment, when both forward and reverse accelerations are detected using only one diaphragm, the detection is performed as follows. In the positive direction from right to left in Figure 3, the inertial force of the mercury weight remains as it is, and the pressure receiving surface of the tire flamm]
It acts on a and becomes a pressurizing force due to acceleration. When the reverse direction of the mouth acceleration acts, mercury is exposed to the atmosphere]
By moving to the 8 side, the diaphragm 11 and the mercury 1
Negative pressure is generated in the small gap between 6 and 6. Therefore,
Based on the magnitude relationship of this negative pressure, the acceleration in the opposite direction is detected in association with the strain generated in the diaphragm.

In this case, the signal is not symmetrical between the forward and reverse directions because the distortion generated in the forward and reverse directions is relatively different, for example, as shown in FIG. 7(e). In addition, if the open end 18 of the pipe in Fig. 3 is sealed and the volume is made small, when used in a high frequency vibration acceleration region, the response of the mercury weight will be delayed and the phase will be delayed, but in this case. Regarding the acceleration in the opposite direction, the inertial force hits the wall surface and becomes a reaction force, causing the pressure receiving surface, L1. For example, the unidirectional signal shown in FIG. 1(f) is obtained.

FIG. 4 shows a fourth embodiment of the present invention, and this embodiment is also designed to detect acceleration in the X-axis or Y-axis direction.

In the fourth embodiment, the mercury space 10 is shaped like a straight tube extending in a straight line in the horizontal direction, and semiconductor diaphragms 11 are arranged at both ends.
, 11'. In this embodiment, when acceleration occurs in the right direction in the drawing, one tire flam 1]'
When the inertia pressure of the mercury weight 16 is applied to the pressure-receiving surface 11'a of the tire flam, and acceleration occurs to the left, the other tire flam 11
The inertial pressure of the mercury weight 16 is applied to the pressure-receiving surface 11a of the mercury weight 16, and the acceleration in either the forward or reverse direction of the X-axis or Y-axis can be detected based on this pressurizing force t. This method is
Detection accuracy can be improved. In addition, the sensor block of the fourth embodiment may be
By arranging them in combination in an integral structure in the three-dimensional directions of the axis, Y-axis, and X-axis, or in the two-dimensional directions such as the XY-axis, YX-axis, Acceleration in the direction of the movement can be detected. Even in the case of such a combination of sensor blocks, common use can be achieved by communicating the mercury of the weight to the same mercury tank as in the first embodiment.

FIG. 5 shows a fifth embodiment of the present invention, and this embodiment is designed to detect acceleration in the Z-axis direction.

In this embodiment, a semiconductor diaphragm 1'' is placed at the bottom of a mercury space 10 arranged vertically, and a hole 1 is placed at the top of the mercury space 10 toward the atmosphere.
8. In the case of the fifth embodiment, the gravitational acceleration of the IG always acts on the diaphragm 11 on the mercury above the diaphragm. Therefore, corresponding distortion also occurs. This distortion is set as a reference value for OG. And the magnitude of the acceleration that the mercury weight above the diaphragm receives.

The distortion corresponding to the direction is added or subtracted from the reference value, a signal output is generated, and the acceleration in the Z-axis direction can be detected.

FIGS. 6(a) and 6(b) show a sixth embodiment of the present invention, and represent a sensor having YZX axis direction acceleration detection specifications. Since the operation is common to each of the embodiments described above, a description thereof will be omitted.

In each of the above embodiments, the diaphragm having a diffused resistance may have a structure in which the inertial force as a mercury weight is applied only to the side without the diffused resistance. In this case, only the magnitude of acceleration is known, and the detected force direction is one direction.

〔Effect of the invention〕

As described above, according to the present invention, by configuring the inertial weight of the acceleration sensor with mercury, it is possible to improve the detection accuracy and reduce the size of the acceleration sensor. Acceleration detection can also be realized with one sensor.

[Brief explanation of the drawing]

FIG. 1(a) is a partially cross-sectional view of a sensor capable of detecting acceleration in three-dimensional directions, as viewed from above, and FIG. a). 2 is a cross-sectional view taken along the line A-A of the present invention, and FIG. 2 is a vertical cross-sectional view of a sensor capable of detecting acceleration in the X-axis or Y-axis direction, and FIG. 3 is a 73rd embodiment of the present invention. , a vertical sectional view showing another example of the sensor for detecting acceleration in the X-axis or Y-axis direction, and FIG. 4 is a longitudinal sectional view showing another example of the sensor for detecting acceleration in the A longitudinal sectional view representing
Fig. 5 is a longitudinal cross-sectional view of a sensor for detecting acceleration in the Z-axis direction according to a fifth embodiment of the present invention, and Fig. 6 (,) is a cross-sectional view of a part of a sensor for detecting acceleration in a two-dimensional direction according to a sixth embodiment of the present invention. 6(b) is a cross-sectional view taken along line A-Δ of FIG. 6(,1),
FIGS. 7(a) to (f) are graphs showing fluctuations in the output voltage of the acceleration sensor, and FIG. 8 is a graph of the output characteristics without showing the relationship between the output voltage and the magnitude of acceleration. 1- Acceleration sensor, 2, 3.4 Sensorf L1, 7.8, 9.10 (], Ox, 10y, 1oz) Mercury storage space, 11 (iix, IJy, 11Z)
Diaphragm. 12(,1,2x,12y,1.2z)
Crow pedestal, Lla, 1.1-1. ),
Iic, 12a. 12b, 12c pressure receiving surface, 1G mercury. 2nd Prisoner 3rd Day 1Ja Dendo Omachi Dormitory 4-Ku 5th Koku Expo '1 Item (a) ('o) (c) (d)
<e) cf) 8th mouth 1'IrJ achievement q

Claims (7)

[Claims] 1. A method that includes an inertial weight that converts acceleration into inertial pressure and a piezoresistive pressure sensing element that detects stress in a diaphragm that is sensitive to this inertial pressure, and detects acceleration based on the output of the pressure sensing element. An acceleration sensor characterized in that the inertial weight is made of mercury. 2. A method that includes an inertial weight that converts acceleration into inertial pressure and a piezoresistive pressure sensing element that detects stress in a diaphragm that is sensitive to this inertial pressure, and detects acceleration based on the output of the pressure sensing element. In this acceleration sensor, mercury is used as the inertial weight, the space for accommodating the mercury is formed into a tubular shape, the diaphragm is disposed facing the tubular space, and the inertia of the mercury applied to the pressure receiving surface of the diaphragm is An acceleration sensor characterized by matching the direction of pressure and acceleration. 3. A method that includes an inertial weight that converts acceleration into inertial pressure and a piezoresistive pressure sensing element that detects stress in a diaphragm that is sensitive to this inertial pressure, and detects acceleration based on the output of the pressure sensing element. In the acceleration sensor, the inertial weight is made of mercury, and the space for accommodating the mercury is branched into multiple axial directions of at least two dimensions, so that the mercury accommodated in each of these branched spaces is made of mercury. A multidimensional acceleration sensor, characterized in that it is set to generate an inertial pressure in response to an acceleration component, and the diaphragm is disposed at a pressure receiving location of the mercury inertial pressure generated in each of the branch spaces. 4. A method that includes an inertial weight that converts acceleration into inertial pressure and a piezoresistive pressure sensing element that detects stress in a diaphragm that is sensitive to this inertial pressure, and detects acceleration based on the output of the pressure sensing element. In the acceleration sensor, the inertial weight is made of mercury, and spaces for accommodating the mercury are arranged on both sides of the diaphragm surface, and the mercury in one side of the accommodating spaces is arranged in one direction. Inertial pressure corresponding to acceleration is applied to one side of the diaphragm, and mercury in the other side space is set to apply inertial pressure corresponding to acceleration in the opposite direction to the other side of the diaphragm. An acceleration sensor featuring: 5. A method that includes an inertial weight that converts acceleration into inertial pressure and a piezoresistive pressure sensing element that detects stress in a diaphragm that is sensitive to this inertial pressure, and detects acceleration based on the output of the pressure sensing element. In the acceleration sensor, the inertial weight is made of mercury, and the space for accommodating the mercury is formed in the shape of a straight tube, and the diaphragm is disposed at each end of the mercury accommodation space. Acceleration sensor. 6. In a third claim, each branch space for accommodating the mercury is further divided into a first space and a second space,
These first and second spaces are arranged on both sides of the diaphragm disposed in each of the branch spaces, and the mercury in the first space applies an inertial pressure corresponding to acceleration in a certain direction to the diaphragm. In addition to one surface of the diaphragm, mercury in the second space is configured to apply inertial pressure corresponding to acceleration in a direction opposite to the one direction to the other surface of the diaphragm. 7. 3. The acceleration sensor according to claim 3, wherein each of the branch spaces for accommodating the mercury has the diaphragm disposed at both axial ends thereof.