JPH10160458A - Tilt sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve correct detections even under an external force, e.g. vibrations or the like, by using a substance having a viscosity dependent on the frequency of the external force for a sensor fluid body. SOLUTION: When the tilt sensor 100 is inclined, a fluid 17 moves in one direction and the ratio of the fluid 17 and a hollow part (air) 15 between an upper electrode 12 and a lower electrode 13 is changed correspondingly to the amount of a shift of the fluid 17. Therefore, an electrostatic capacity between the electrodes is changed from a reference value when the tilt sensor 100 is in the horizontal state. A tilt angle can be obtained by detecting the amount of the change. Further, when the tilt sensor 100 is inclined, the electrostatic capacity between the upper electrodes 12 and each of the lower electrodes 13a-13d varies. A tilt direction can be detected at the same time as the tilt angle if the change of the electrostatic capacity is detected for each lower electrode 13a-13d or the electrostatic capacities of the lower electrodes 13a-13d are compared. When a substance having dependency on a frequency, e.g. Reversefoam (a silicone) is used as the fluid body 17, the tilt angle can be measured more correctly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tilt sensor,
In particular, the present invention relates to a tilt sensor that measures a tilt angle using a change in an output signal according to a tilt.

[0002]

2. Description of the Related Art As an inclination sensor for measuring an inclination angle using a change in an output signal, there is, for example, a sensor using a change in capacitance. Generally, in a tilt sensor using a change in capacitance, a fluid is sealed in a closed container forming an upper electrode and a lower electrode. As such a fluid, silicone oil (for example, JP-A-6-174)
No. 535) and ketone-based liquids. Note that the closed container is a container having a configuration in which the sealed liquid does not easily leak.

[0003] Inside a closed container, there is a hollow portion (air) that is not filled with a fluid. When the tilt sensor is tilted, the enclosed fluid is displaced in accordance with the amount of tilt, so that the arrangement of the fluid sandwiched between the opposing electrodes changes. Therefore, the distribution of the fluid and the air between the electrodes changes according to the amount of inclination, and as a result, the capacitance between both electrodes changes. By detecting the change in the capacitance as a signal, the inclination can be measured.

[0004]

However, since silicone oil and ketone-based liquids have low viscosity, they are easily displaced by external force such as vibration applied to the tilt sensor or sudden acceleration. Therefore, when the tilt sensor is configured to detect a static tilt amount (for example, a tilt of a vehicle body on a slope), the displacement of the fluid due to such vibration and acceleration is not limited to the tilt to be actually measured. Is detected as a signal. Such a signal becomes a noise signal and prevents correct tilt measurement.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and aims to (1) eliminate the need for a signal processing circuit for removing unnecessary signal components due to external force such as vibration, and perform measurement. It is an object of the present invention to provide a tilt sensor which detects a signal (tilt component) indicating a tilt to be measured and (2) can easily measure a correct tilt even under a situation where an external force such as vibration is applied.

[0006]

A tilt sensor according to the present invention includes an upper electrode, a lower electrode, and a fluid sealed between the upper electrode and the lower electrode and displaced according to the tilt. A tilt sensor for measuring a tilt angle by extracting a change in an output signal due to a displacement of a fluid, wherein the fluid uses a substance whose viscosity depends on a frequency of an external force. Achieved.

It is preferable that the fluid is a substance exhibiting a predetermined viscosity or higher with respect to an external force having a predetermined frequency or higher.

[0008] The lower electrode may be divided into a plurality of portions.

[0009] In one embodiment, the output signal is a signal indicating a change in capacitance based on a displacement of the fluid.

[0010] In another embodiment, the output signal is a signal indicating a change in resistance based on a displacement of the fluid.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings with reference to the accompanying drawings.

(Embodiment 1) FIGS. 1 (a) and 1 (b)
1A and 1B show the appearance of a tilt sensor 100 according to a first embodiment. FIG. 1A is a bottom view and FIG. 1B is a side view. FIG. 2 shows a cross-sectional configuration of the tilt sensor 100.

First, an outline of the tilt sensor 100 will be described. As shown in these figures, the tilt sensor 100
Are an upper member 10 having an upper electrode 12 and a lower electrode 1
A closed container is formed by the lower member 11 having 3 (13a to 13d). In the present embodiment, as shown in FIG.
a to 13d. In the following description, when the lower electrodes 13a to 13d are collectively shown, they will be referred to as lower electrodes 13.

A fluid 17 is sealed in the closed container. The fluid 17 is interposed between the upper electrode 12 and the lower electrode 13. The upper electrode 12 and the lower electrode 13 are substantially opposed to each other across a space formed by the closed container, and the upper electrode 12 and the lower electrode 13 are formed by a substance existing in the space between the upper electrode 12 and the lower electrode 13. 13 is determined. As shown in FIG. 3, when the inclination sensor 100 is inclined, the fluid 17 is displaced according to the inclination. The capacitance between the two electrodes changes due to the displacement of the fluid 17. The inclination angle is measured by detecting the change in the capacitance. The fluid 17 has a viscosity of the fluid 17.
Is a substance that depends on the frequency of external force applied to

Next, the configuration and operation of the tilt sensor 100 will be described in more detail. As shown in FIG. 1B, the upper member 10 is a plate-shaped member, on which a disk-shaped upper electrode 12 is provided. The lower member 11 is shown in FIG.
As shown in FIG. 2A and FIG. 2, a curved portion 11a formed in the center in a round shape and a flat plate portion 11b around the curved portion 11a are provided. The lower electrode 13 is provided outside the curved portion 11a. The lower electrode 13 includes a plurality of portions 13a to 13d as shown in FIG. Preferably, lower electrodes 13a to 13d are formed in a shape obtained by dividing an electrode formed along curved portion 11a into four parts.

In the above example, the upper electrode 12 and the lower electrode 13 are provided outside (front side) of the upper member 10 and the lower member, respectively.
3, one or both of them may be provided on the inside (back side) of the upper member 10 and the lower member, respectively (FIGS. 4A to 4C).

The flat plate portion 11b of the lower member 11 is
0, a closed container 14 is formed, and a fluid 17 is sealed in a space formed by the curved portion 11b of the upper member 10 and the lower member 11. Fluid 1
7 is sealed so as to fill a predetermined portion of the closed container 14,
The portion of the closed container 14 that is not filled with the fluid 17 is hollow. This hollow part may be, for example, air. The “closed” container may be in a closed state that does not allow the fluid 13 to easily leak, and does not need to be completely airtight. Further, the shape of the sealed container 14 is not limited to the shape of the curved portion 11a as illustrated, but may be any shape in which the upper electrode 12 and the lower electrode 13 substantially face each other and a space is formed therebetween. I just need. Further, for convenience of measuring the direction of inclination as described later, the shape of the curved portion 11a is preferably rotationally symmetric about a vertical axis when the inclination sensor 100 is placed in a horizontal state.

As shown in FIG. 1B, the upper electrode 1
2, a voltage is applied to the lower electrodes 13a to 13d.
, Potentials V _{A to} V _D with respect to the upper electrode 12 are detected. As shown in FIG. 2, when the tilt sensor 100 is in a horizontal state (a state in which there is no tilt), the fluid 17 exists symmetrically in the closed container and has a predetermined capacitance (reference value).
Is shown. As shown in FIG. 3, when the inclination sensor 100 is inclined, the fluid 17 moves to one side, and the fluid 17 existing between the upper electrode 12 and the lower electrode 13 is moved according to the displacement of the fluid 17. The ratio with the hollow portion (air) 15 changes.
Therefore, the capacitance between the two electrodes changes from the reference value when the tilt sensor 100 is in the horizontal state. By detecting the amount of change, the inclination angle can be measured.

When the lower electrode 13 is divided into 13a to 13d, when the tilt sensor 100 is in a horizontal state, the capacitance formed between the upper electrode 12 and the lower electrode 13 is: The same applies to all of the lower electrodes 13a to 13d (reference value). When the tilt sensor 100 tilts, the fluid 17 is displaced as described above, so that the overall capacitance changes and at the same time the upper electrode 12 and the lower electrode 1
There is also a difference in the capacitance formed between each of 3a to 13d. By detecting a change in the capacitance of each of the lower electrodes 13a to 13d, or by comparing the capacitance detected from each of the lower electrodes 13a to 13d, the inclination direction can be detected simultaneously with the inclination angle.

Hereinafter, the detection of the capacitance will be described in more detail.

In general, when two electrodes having an area S are arranged at a distance d and a medium of a dielectric substance ε exists between the two electrodes, the capacitance C between the two electrodes is C = ε (S / d ). In the tilt sensor 100, the upper electrode 12 and the lower electrode 13 are not arranged in parallel at a fixed interval. However, when a minute portion sandwiched between both electrodes is applied to the case of the two parallel electrodes described above. I do. Therefore, in the case of the tilt sensor 100, the first medium (fluid 17) having the dielectric constant ε ₁ and the thickness d ₁ and the dielectric constant ε ₂ and the thickness d ₂ are provided between the electrodes having the area S for the minute portion. Second medium (air)
And are held. In this case, the capacitance C ′ between both electrodes is given by C ′ = S / (d ₁ / ε ₁ + d ₂ / ε ₂ ).

In the case of the inclination sensor 100, assuming that the permittivity ε ₁ and ε _{2 of} the fluid 17 and the air are respectively predetermined values, when the inclination sensor 100 is in a horizontal state (FIG. 2), the fluid 17 is curved. The portion 17a is uniformly filled with the fluid 17
Is parallel to the upper electrode 12 (upper member 10). Therefore, the thickness d ₂ of the air portion becomes a constant value corresponding to the amount of the fluid 17, and the thickness d ₁ of the fluid 17 depends on the shape of the closed container (the curved portion 11 a) and the position x on the curved portion 11 a. Is defined by a predetermined function d ₁ (x). The capacitance between the upper electrode 12 and the lower electrode 13 is obtained by adding the values in the minute portion (that is, integrating the position x). More practically, as shown in FIG. 1B, each of the lower electrodes 13a to 13a in a horizontal state is
The output voltages V _{A to} V _D from 3d are measured, and a reference voltage for measuring the inclination angle is obtained. The electrode arrangement in the present embodiment, in the horizontal state, the output voltage V _A ~V _D from the lower electrodes 13a~13d are equal respectively.

When the tilt sensor 100 tilts (FIG. 3),
The fluid 17 is displaced to one side of the curved portion 11a according to the inclination, and the level surface of the fluid 17 forms an angle (inclination angle θ) with respect to the upper electrode 12. Therefore, the thickness d ₁ of the fluid 17
And the thickness d _{2 of the} air portion, the position x and the inclination angle θ
Is a function of For example, as shown in FIG. 3, the arrangement of the fluid 17 between the upper electrode 12 and the lower electrode 13 changes according to the inclination angle θ. The integrated capacitance between the upper electrode 12 and the lower electrode 13) is a function of the tilt angle θ. As described above, the inclination angle θ can be obtained from the change in the capacitance C.

As shown in FIG. 3, when the tilt sensor 100 is tilted to the left in the figure, the region sandwiched between the upper electrode 12 and the lower electrode 13d is almost completely filled with the fluid 17, but on the opposite side. The hollow portion 15 increases in a region sandwiched between the upper electrode 12 and the lower electrode 13a. Therefore, there is a difference between the capacitance between the upper electrode 12 and the lower electrode 13a and the capacitance between the upper electrode 12 and the lower electrode 13d. This difference is caused by the inclination angle θ and the inclination direction (for example,
Azimuth). That is, for each inclination angle θ, the capacitance formed between the upper electrode 12 and each of the lower electrodes 13a to 13d differs depending on the direction of the inclination. The difference in capacitance between the lower electrode 13 a to 13 d is detected as the difference of the output voltage V _A ~V _D from the lower electrode 13 a to 13 d, these output voltage V
It is possible to obtain the direction of inclination from _A ~V _D. In this way, by dividing the lower electrode 13 into a plurality of parts, the inclination angle θ and the direction of the inclination can be measured.

In practice, for example, when the inclination angle θ and the direction of the inclination are variously changed, the output voltages V _{A to} V _D from the lower electrodes 13 a to 13 _d are measured in advance, and a table based on the actually measured values is obtained. Is created. Such a table is stored in, for example, a ROM, and the tilt angle θ is calculated based on the output voltage detected by referring to the table.
And its direction.

Next, the fluid 1 used in the present embodiment
7 will be described. As described above, the tilt sensor 100
Measures the inclination angle θ based on the change in capacitance due to the displacement of the fluid 17 according to the inclination angle θ. Here, the operation of the fluid 17 in the tilt sensor 100 will be considered. When the tilt sensor 100 is in the horizontal state, the potential energy of the fluid 17 is minimum (minimum) in the closed container (FIG. 2). When the tilt sensor 100 tilts,
The fluid 17 moves along the inclined closed container, depending on the friction with the wall surface of the closed container, the inertia of the fluid 17, and the like. Therefore, the arrangement of the fluid 17 in the closed container is
It will deviate from its minimum energy state. The fluid 17 has a gravitational acceleration (ie, an external force,
Or, it is deformed in the closed container in accordance with the load) and is settled at a predetermined position giving the minimum potential energy in the inclined closed container (the state of FIG. 3).

As described above, the external force acting on the fluid 17 due to the inclination is a force based on the gravitational acceleration. Therefore,
The magnitude of the force is substantially constant per unit volume, and only the direction changes with a change in tilt. For example, in the case of an in-vehicle inclination sensor, the external force applied to the inclination sensor does not change so rapidly due to a change in the inclination (hill) of the road on which the vehicle runs, and the external force due to the inclination becomes a low-frequency load. On the other hand, the external force applied by vibration of the vehicle body due to unevenness of the road surface or sudden acceleration is a load of a relatively high frequency.

The present applicant has paid attention to the difference in frequency between the external force due to the inclination and the external force due to other vibrations, and has conceived of using a substance whose viscosity depends on the frequency of the external force as the fluid 17. . That is, the viscous resistance of the fluid 17 varies depending on how rapidly the external force changes, and the response to the external force (displacement and deformation).
Decided to use a substance that depends on the frequency of the external force. In particular, a substance whose viscosity becomes equal to or higher than a predetermined value with respect to an external force equal to or higher than a predetermined frequency is preferable.

As such a material, for example, a reverse foam made of a baking putty can be used. Reverse form, for moderate load,
It is a substance that deforms by absorbing the shock, but does not deform under a sudden force and shows elasticity. For example, it is used in the heel of certain sports shoes. Reverse-form polymers have loose bonds called pseudo bonds. This quasi-bond easily breaks with slow forces (low-frequency energy stimulation), causing the polymers to slide. In addition, it shows a strong coupling force against a sudden force (high-frequency energy stimulation). Also, once broken bonds are formed again over time. FIG. 5 shows an example of a pseudo join of the reverse form. In FIG.
Si represents silicon, O represents oxygen, B represents boron, and R represents an organic group (methyl group). Oxygen O and boron B connecting polymers
Is a pseudo bond.

FIG. 6 schematically shows the frequency dependence of the response to an external force of the bansing putty used for the reverse foam. In FIG. 6, the frequency dependency of the bansing putty is indicated by a curve 60. For comparison, high damping (damping) silicone rubber (curve 6)
1), the frequency dependence of carbon-containing natural rubber (curve 62) and the frequency dependence of normal silicone rubber (curve 63) are shown together. The data shown in FIG. 6 is a result when each substance is formed in a round bar shape and a torsional force is applied as an external force (room temperature 25 ° C.). The horizontal axis of the graph in FIG. 6 is the frequency of the external force (torsion force), and the vertical axis is the shear modulus (tan δ) of each substance with respect to the frequency of the external force. Here, δ corresponds to the magnitude of the twist angle of the round bar with respect to the twisting force. That is, the larger the value of δ is, the more easily it is deformed and the lower the viscosity is.
Note that both the vertical and horizontal axes of the graph are on a logarithmic scale.

As can be seen from the curve 60, when the frequency of the external force is low, that is, when it is twisted slowly, it is very "soft" and easily deforms (low viscosity) according to the external force. As the frequency of the external force increases, the response of the bashing putty becomes "harder" (higher viscosity). As shown by curve 60, the viscosity of the bansing putty is such that the frequency of the external force is between 0.1 Hz and 100 Hz,
It changes about 30 times on a logarithmic scale. Curves 61-63
As can be seen from the above, other rubber materials do not show such frequency dependence of viscosity with respect to external force. still,
This value is merely an example, and the rate of change of the viscosity with respect to the frequency of the banding putty can be changed according to the composition of the material.

Therefore, the reverse foam made of such a bansing putty is used as the fluid 1 of the tilt sensor 100.
When used as 7, a small displacement can be obtained with respect to a fast load due to vibration, rapid acceleration, or the like, and a displacement corresponding to the load (that is, the inclination angle) can be obtained with respect to a slow load due to inclination. As a result, the tilt sensor 100 can detect only a pure tilt component excluding vibration and a sharp acceleration component.

For example, when the inclination sensor 100 is used as an on-vehicle sensor, the fluid 17 (shown as having a high viscosity in a frequency range (for example, 0.1 H to 1 Hz) characteristic of a running vehicle). By setting the composition of the reverse form, for example), it is possible to accurately measure the inclination angle without the influence of vibration.

Further, the conventional weight / tilt sensor using a ketone-based solution as the fluid has a limited operating temperature of about 80 ° C. or lower because the boiling point of the ketone-based solution is low.
In the case of the reverse foam, the boiling point is considerably high similarly to the silicone oil, so that the inclination angle can be measured under a wide range of temperature conditions.

As described above, according to the present embodiment, by using a material having a frequency-dependent viscosity (for example, a reverse form) as the fluid 17 of the tilt sensor 100, unnecessary fluid due to vibration, rapid acceleration, or the like is used. A signal (slope component) representing a slope to be measured can be selectively detected without requiring a signal processing circuit for removing a signal component.

In vehicle control, the present invention can be applied to, for example, engine output control and brake control in accordance with the inclination. In particular, since the brake control (ABS or the like) is performed during traveling, the tilt sensor of the present invention is effective. For example, by measuring the inclination using the inclination sensor according to the present invention, it is possible to perform control such as not to make the brakes too weak even in anti-block control on a downhill.

(Embodiment 2) FIGS. 7 (a) and 7 (b)
9 shows a cross-sectional configuration of a tilt sensor 200 according to another embodiment of the present invention. FIG. 7A shows a state in which the inclination sensor 200 is horizontal, and FIG. 7B shows a state in which the inclination sensor 200 is inclined. The basic structure of the tilt sensor 200 is the same as the structure of the tilt sensor 100 according to the first embodiment,
Detailed description is omitted. The same components as those of the tilt sensor 100 are denoted by the same reference numerals. In the tilt sensor 200, not only the fluid 17 but also a movable member 18 is sealed in a sealed container formed by the upper member 10 and the lower member 11. The movable member 18 is a member that easily moves in the closed container 14 and has a large specific gravity, such as a metal ball.

Since the specific gravity of the reverse form is about 0.3, the inertia force of the inclination sensor 200 can be increased by inserting the relatively heavy movable member 18. Due to the synergistic effect of the movable member 18 and the fluid 17, the sensitivity to inclination can be increased. For example, the influence of a small external force due to a minute vibration or the like can be reduced by the movable member 18 having a large inertia. When the movable member 18 tries to move suddenly due to a high frequency external force such as large vibration or sudden acceleration, the movement of the movable member is prevented by the high viscous resistance of the fluid 17. When a low-frequency external force due to the inclination angle to be measured is applied, the fluid 1
Since 7 has a low viscosity, it is displaced together with the movable member 18 according to an external force (inclination).

By placing the movable member 18 in the fluid 17, the calculation of the capacitance formed between the upper electrode 12 and the lower electrode 13 becomes complicated, but can be theoretically performed. More practically, as in the case of the first embodiment, the lower electrode 1 has a different inclination angle θ and its inclination direction.
By actually measuring the voltage values detected from 3a to 13d and creating a reference table, the inclination angle and the inclination direction can be more easily obtained.

(Embodiment 3) FIG. 8 shows a sectional configuration of a tilt sensor 300 according to another embodiment of the present invention. The basic structure of the tilt sensor 300 is the same as the structure of the tilt sensor 100 according to the first embodiment, and a detailed description will be omitted. The same components as those of the tilt sensor 100 are denoted by the same reference numerals.

In the tilt sensor 300, the upper member 1
0 and the lower member 11 in a closed container,
A fluid 19 is sealed in place of the fluid 17. The fluid 19 is obtained by dispersing metal powder or ferroelectric powder in the same medium as the fluid 17 (for example, a substance such as a reverse foam).

First, a case in which a metal powder (eg, Fe powder, Al powder, etc.) is dispersed in a medium will be described as the fluid 19. In this case, since the fluid 19 exhibits conductivity, the amount of tilt can be detected by measuring the resistance between the upper electrode 12 and the lower electrode 13 and detecting the change. Therefore, the signal processing circuit for measuring the inclination angle can be simplified.

The relationship between the resistance value between the two electrodes (the upper electrode 12 and the lower electrodes 13a to 13d) and the respective inclination angles and the directions of the inclinations is measured in advance and a reference table is obtained as in the above embodiment. Can be created.

When a fluid in which a ferroelectric powder (eg, SiO ₂ powder, Ta powder, or the like) is dispersed in a medium is used as the fluid 19, the dielectric constant of the fluid 19 may be increased. it can. Therefore, the upper electrode 1 for a change in the tilt angle
Since the change in capacitance between the second electrode 13 and the lower electrode 13 becomes larger, the resolution of tilt angle detection can be increased. Also in this case, similarly to the above, the relationship between the capacitance between the two electrodes (the upper electrode 12 and the lower electrodes 13a to 13d) and the respective inclination angles and the directions of the inclinations are measured in advance to obtain the reference table. Can be created.

(Embodiment 4) In the first to third embodiments, the tilt sensor using a fluid having a high viscosity in a certain frequency range as a substance having a frequency-dependent viscosity has been described. . The present invention is not limited to this example, and can be prevented from being detected by an external force such as acceleration or vibration by the following embodiments.

For example, two inclination sensors using materials having different frequency dependences of viscosity are used in combination. That is, a first inclination sensor using the first fluid whose viscosity is substantially constant regardless of the frequency of the external force, and a second fluid whose viscosity decreases as the frequency of the external force increases are used. It is used in combination with the second tilt sensor.
The basic structure of the first and second tilt sensors can be the same as the tilt sensors of the first to third embodiments described above. From the first and second tilt sensors, output signals (detected values) corresponding to the displacements of the respective fluids are obtained.

Since the fluid of the first tilt sensor is a substance having substantially no frequency dependence (substantially constant viscosity), the output signal of the first tilt sensor includes a tilt angle signal representing a true tilt angle and an acceleration signal. And signals due to external forces such as vibration and the like. On the other hand, since the fluid of the second tilt sensor becomes lower in viscosity as the frequency becomes higher, it responds well to high-frequency displacement due to acceleration or vibration, but does not respond to low-frequency displacement due to the tilt angle. Therefore, the output signal of the second tilt sensor is substantially only a signal based on an external force such as acceleration or vibration. From the output signal of the first tilt sensor,
By subtracting the output signal of the second tilt sensor, only the tilt angle signal representing the true tilt angle can be extracted.

In the subtraction of the two output signals from the first and second tilt sensors, each output signal is adjusted so that a signal due to an external force is effectively removed, or each output signal is adjusted as necessary. The output signal can be weighted and subtracted.

[0049]

As described above, according to the tilt sensor of the present invention, no signal processing circuit for removing unnecessary signal components due to an external force such as acceleration or vibration is not required, and the signal representing the tilt to be measured ( Gradient component) can be accurately detected.

Further, according to the tilt sensor of the present invention, erroneous detection due to external force such as acceleration or vibration can be prevented, so that the tilt sensor can be used in a situation where external force is applied in addition to tilt. For example, when used as an in-vehicle inclination sensor, inclination can be measured even in a running vehicle. In particular, the inclination can be measured even while traveling on a rough road surface.

[Brief description of the drawings]

FIG. 1 is a view showing the appearance of a tilt sensor according to the present invention, wherein (a) is a bottom plan view and (b) is a side view.

FIG. 2 is a cross-sectional view illustrating a state where a tilt sensor according to an embodiment of the present invention is in a horizontal state.

FIG. 3 is a cross-sectional view illustrating a state in which a tilt sensor according to one embodiment of the present invention is tilted.

FIGS. 4A to 4C are diagrams showing examples of electrode arrangement in the tilt sensor of the present invention.

FIG. 5 is a diagram showing an example of a composition of a substance (reverse form) used for a fluid of the tilt sensor of the present invention.

FIG. 6 is a diagram schematically showing the dependence of the viscosity of a substance (reverse form) used for a fluid of the tilt sensor of the present invention on the frequency of an external force.

FIGS. 7A and 7B are views showing a cross section (horizontal state and inclined state) of an inclination sensor according to another embodiment of the present invention.

FIG. 8 is a diagram showing a cross section of a tilt sensor according to another embodiment of the present invention.

[Explanation of symbols]

 100, 200, 300 Inclination sensor 10 Upper member 11 Lower member 11a Curved portion 11b Flat plate portion 12 Upper electrode 13 (13a to 13d) Lower electrode 14 Sealed container 15 Hollow portion 17 Fluid 18 Movable member 19 Fluid

Claims (5)

[Claims] 1. A system comprising an upper electrode, a lower electrode, and a fluid sealed between the upper electrode and the lower electrode, the fluid being displaced in accordance with an inclination, and a change in an output signal due to the displacement of the fluid. A tilt sensor for measuring a tilt angle by taking out a fluid, wherein a material whose viscosity depends on the frequency of an external force is used as the fluid. 2. The tilt sensor according to claim 1, wherein the fluid is a substance exhibiting a predetermined viscosity or higher with respect to an external force having a predetermined frequency or higher. 3. The tilt sensor according to claim 1, wherein the lower electrode is divided into a plurality of portions. 4. The tilt sensor according to claim 1, wherein the output signal is a signal indicating a change in capacitance based on a displacement of the fluid. 5. The tilt sensor according to claim 1, wherein the output signal is a signal indicating a change in resistance based on a displacement of the fluid.