JP4515167B2 - Capacitance medium and capacitance type tilt angle sensor - Google Patents

Description

  The present invention relates to a capacitance medium accommodated in a capacitor and the like, and a capacitance type inclination angle sensor that is mounted on, for example, a surveying instrument or a vehicle and detects an inclination angle.

Conventionally, as a specific example using a liquid capacitive medium, for example, a capacitance type tilt angle sensor (hereinafter simply referred to as “tilt angle sensor”) described in Patent Document 1 has been proposed. The tilt angle sensor includes a capacitor formed by an oil case, a liquid capacitive medium accommodated in the oil case, and a portion disposed in the oil case and immersed in the capacitive medium. Two differential electrodes and a common electrode are provided. In such a horizontal state of the tilt angle sensor, since the area (immersion area) of the portion immersed in the capacitance medium in each differential electrode is substantially the same, the capacitance of each capacitor is substantially the same. On the other hand, when the tilt angle sensor is tilted, the immersion area of one differential electrode increases and the immersion area of the other differential electrode decreases, so that a difference occurs in the capacitance of each capacitor. The tilt angle sensor calculates the tilt angle based on the difference in capacitance. In this tilt angle sensor, silicone oil is used as a capacitance medium. In general, silicone oil has stable properties and is excellent in heat resistance, cold resistance, oxidation resistance, and the like. Therefore, by using silicone oil as the capacitance medium, a highly reliable tilt angle sensor that suppresses performance deterioration is realized.
Japanese Patent Laid-Open No. 08-261757

By the way, since such a conventional tilt angle sensor has a volume as large as several cm ³ to several tens of cm ³ , in recent years, downsizing of the tilt angle sensor has been demanded. However, simply downsizing the tilt angle sensor to meet these needs reduces the amount of capacitive medium accommodated in the oil case and reduces the immersion area of the differential electrode. The capacity will be reduced. In particular, since the relative permittivity of silicone oil is as low as about 2.7, when silicone oil is used as the capacitance medium, the amount of change in capacitance during tilting can be reduced by simply downsizing the tilt angle sensor. Will become smaller. As a result, there arises a problem that the detection reliability, detection resolution and the like of the tilt angle sensor are lowered. In addition, when an organic solvent having a dielectric constant higher than that of silicone oil is used as a capacitance medium, such problems are less likely to occur, but performance degradation occurs because heat resistance, cold resistance, oxidation resistance, etc. are reduced. It becomes easy.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a capacitance medium capable of suppressing performance deterioration and improving dielectric constant.
Another object of the present invention is to provide a capacitance type tilt angle sensor that can be miniaturized while preventing performance degradation and performance degradation.

In order to solve the above problems, in the invention according to claim 1, the liquid base consisting of modified silicone oil, Ri Na are mixed particulates higher dielectric constant than the base, the fine particles, The gist is that it is set to a size capable of floating by Brownian motion within the base .

In the invention described in 請 Motomeko 2, in the electrostatic capacity medium of claim 1, wherein the modified silicone oil is summarized in that a reactive silicone oil.

According to a third aspect of the present invention, there is provided a capacitor that is provided on the opposite inner wall surface of the capacitive medium according to the first or second aspect , a case that accommodates the capacitive medium, and the case. The gist of the invention is that the differential electrode and the common electrode are partially immersed in the capacitance medium, and the capacitance of the capacitor is changed according to the inclination of the case.

The “action” of the present invention will be described below.
According to the first aspect of the present invention, it is possible to reliably and easily increase the dielectric constant of the capacitance medium by mixing fine particles having a dielectric constant higher than that of the modified silicone oil into the modified silicone oil. Become. Further, by using the modified silicone oil as the base, the heat resistance, cold resistance, oxidation resistance and the like of the capacitance medium are maintained, so that the performance deterioration of the capacitance medium is also suppressed. Moreover, since the interfacial tension of the base with respect to the fine particles can be lowered by using the modified silicone oil as the base, the dispersion stability of the fine particles mixed in the base can be improved. Therefore, variations in the dielectric constant of the electrostatic capacity medium can be made difficult to occur.

In particular, the fine particles cause Brownian motion in the base, so that they float in the base and diffuse evenly. Therefore, variations in the dielectric constant of the capacitance medium can be made more difficult to occur.

According to the second aspect of the present invention, it is possible to further improve the dispersion stability of the fine particles in the base by using the reactive silicone oil as the base.
According to the third aspect of the present invention, since the dielectric constant of the capacitance medium can be reliably and easily increased, a high capacitance is ensured even if the capacitance type tilt angle sensor is downsized. Thus, detection reliability, detection resolution, and the like are not reduced. Further, by using the modified silicone oil as the base, the heat resistance, cold resistance, oxidation resistance and the like of the capacitance medium are maintained, so that the performance deterioration of the capacitance medium is also suppressed. Moreover, by using the modified silicone oil as the base, the dispersion stability of the fine particles mixed in the base can be improved, and a high dielectric constant of the capacitance medium can be ensured. Therefore, it is possible to realize a capacitance type tilt angle sensor that can be miniaturized while preventing performance degradation and performance degradation.

As described above in detail, according to the first or second aspect of the present invention, it is possible to provide a capacitance medium capable of suppressing performance deterioration and improving the dielectric constant.
In addition, according to the third aspect of the present invention, it is possible to provide a capacitance type tilt angle sensor that can be downsized while preventing performance degradation and performance degradation.

Hereinafter, an embodiment in which the present invention is embodied as a capacitance type tilt angle sensor will be described in detail with reference to FIGS.
FIG. 1A is a front view of a cross section of a part of a capacitance type tilt angle sensor (hereinafter simply referred to as “tilt angle sensor”) 1 of the present embodiment. FIG. 1B is a cross-sectional view in which a part of the tilt angle sensor 1 is broken. In addition, the cross-sectional position in FIG.1 (b) is an AA line position of Fig.1 (a), and the cross-sectional position in Fig.1 (a) is a BB line position of FIG.1 (b).

  As shown in FIG. 1, the tilt angle sensor 1 includes a case 11. The case 11 includes a first wall portion 12, a second wall portion 13, and a third wall portion 14 made of synthetic resin. As shown in FIG. 1B, the first wall portion 12 and the second wall portion 13 are disposed to face each other, and the third wall portion 14 is disposed between both wall portions 12 and 13. The 1st wall part 12 and the 2nd wall part 13 are comprised with the board | plate material about 4-6 mm in length and width.

  As shown in FIG. 2, common electrodes 15 a and 15 b are provided on the wall surface facing the second wall portion 13 in the first wall portion 12, and the wall surface facing the first wall portion 12 in the second wall portion 13. Are provided with differential electrodes 16a and 16b. The common electrodes 15a and 15b and the differential electrodes 16a and 16b each have a substantially semicircular shape, and the common electrodes 15a and 15b and the differential electrodes 16a and 16b are arranged to face each other. These electrodes 15a, 15b, 16a, and 16b are formed using processing techniques such as hot embossing, printing, and vapor deposition. As shown in FIGS. 1 and 2, terminal portions 15c and 15d are formed on the common electrodes 15a and 15b, respectively, and terminal portions 16c and 16d are formed on the differential electrodes 16a and 16b, respectively.

  The third wall portion 14 has a ring shape and is provided between the common electrodes 15a and 15b and the differential electrodes 16a and 16b. The outer periphery of the third wall portion 14 is formed to coincide with the outer periphery of the common electrodes 15a and 15b and the differential electrodes 16a and 16b. The third wall portion 14 is formed so that the distance between the common electrodes 15a and 15b and the differential electrodes 16a and 16b is a predetermined distance H (30 to 40 μm in this embodiment). Moreover, the 3rd wall part 14 is formed so that the internal diameter R shown to Fig.1 (a) may be set to about 3-5 mm. With such a configuration, the case 11 has a circular cup shape, and the accommodation space C is provided therein.

  A first columnar object 21 as a convex portion is disposed in the central portion in the accommodation space C. The first columnar object 21 has a cylindrical shape, and is provided so that the center coincides with the center O of the accommodation space C. The upper surface of the first columnar member 21 is connected to the common electrodes 15 a and 15 b and the inner wall surface of the first wall portion 12 facing the second wall portion 13, and the lower surface is connected to the differential electrodes 16 a and 16 b and the second wall portion 13. It is connected to the inner wall surface facing the first wall portion 12. Further, on the concentric circumference of the first columnar object 21 that divides the distance between the outer peripheral surface of the first columnar object 21 and the inner peripheral surface of the third wall portion 14 into a plurality of equal parts (here, four equal parts), respectively. A second columnar object 22 is provided as a plurality of convex portions set to have a smaller diameter than the first columnar object. These second columnar objects 22 have a columnar shape, and upper surfaces are connected to the opposing inner wall surfaces of the common electrodes 15a and 15b and the first wall portion 12, and a lower surface is the above-described differential electrodes 16a and 16b and the second wall portion 13. It is connected to the opposite inner wall surface. In the present embodiment, the second columnar objects 22 are provided at equal intervals on each circumference. Further, each second columnar object 22 is arranged so that a straight line (for example, a straight line L shown in FIG. 1A) connecting the second columnar objects 22 closest to each other on the other circle passes through the center O. It is installed. In the present embodiment, the second columnar object 22 on each circumference is provided at each position displaced by 10 ° with respect to the center O. Further, in FIGS. 1A and 5, only a part of the second columnar object 22 is shown in order to simplify the drawing.

  In the accommodation space C, the liquid capacitive medium 23 is accommodated so as to occupy about half of the accommodation space C. For this reason, in the horizontal state of the tilt angle sensor 1 (the state shown in FIG. 1A), about half of the common electrodes 15a and 15b and the differential electrodes 16a and 16b are immersed in the capacitance medium 23. It becomes a state. Therefore, the immersed part functions as a capacitor. Specifically, the first capacitor includes a portion immersed in the capacitance medium 23 in the common electrode 15a and the differential electrode 16a, and includes a portion immersed in the capacitance medium 23 in the common electrode 15b and the differential electrode 16b. Each of the second capacitors is configured. When the tilt angle sensor 1 is kept horizontal, the areas of the common electrodes 15a and 15b and the differential electrodes 16a and 16b that are immersed in the capacitance medium 23 are substantially equal. Capacitors have almost the same capacitance.

  As shown in FIG. 3, the capacitance medium 23 is composed of a liquid base 23a (dispersion medium) made of an insulator, and fine particles 23b (dispersoid) made of an insulator mixed in the base 23a. It is configured.

  The base 23a is composed of a modified silicone oil in which a part of the side chain or terminal group of the silicone molecule is chemically replaced with another molecule. Specifically, the base 23a is made of a modified silicone oil (relative permittivity εa = about 2.7) such as a reactive silicone oil or a non-reactive silicone oil. It has a modified structure of either one of both terminal types. Examples of the reactive silicone oil include amino-modified, epoxy-modified, carboxyl-modified, methacryl-modified, mercapto-modified, phenol-modified, and different functional group-modified silicone oils. Examples of the non-reactive silicone oil include polyether-modified, methylstyryl-modified, alkyl-modified, higher fatty acid ester-modified, hydrophilic special modification, higher alkoxy-modified, higher fatty acid-containing, fluorine-modified silicone oil and the like.

  The fine particles 23b are nanoparticles formed to have a particle size of several tens of nanometers, and are mixed in the base 23a so as to occupy about 3 to 10% of the capacitance medium 23. Thus, since the fine particles 23b are formed very minutely, they float in the base 23a due to Brownian motion. Therefore, the fine particles 23b float in the base 23a and are uniformly mixed. In particular, since modified silicone oil is used as the base 23a, the fine particles 23b are easily mixed uniformly in the base 23a.

  Incidentally, when 8% of alumina (relative permittivity εb = 8.9) is mixed in dimethyl silicone oil (relative permittivity εa = 2.7), the relative permittivity εc = of the mixture is 3.1. Has been confirmed. Therefore, the relative permittivity εc of the capacitance medium 23 when the modified silicone oil is used as the base 23a, alumina is used as the fine particles 23b, and the mixing ratio of the fine particles 23b to the base 23a is 8%, It is estimated to be about 3.1. That is, in this case, the relative dielectric constant εc is increased by about 15% compared to the case where only the base 23 a is used as the capacitance medium 23. Therefore, the relative dielectric constant εc of the capacitance medium 23 can be reliably and easily increased.

  Examples of the substance applied as the fine particles 23b include alumina, non-conductors such as alumina and zirconia (relative permittivity εb = 50), and conductors such as gold, silver, copper, and nickel. . For example, when barium titanate (relative permittivity εb = 1000 or more) is used as the fine particles, the relative permittivity εc of the capacitance medium 23 is about 135 in the calculation. Therefore, it is presumed that the specific dielectric constant is about 50 times that of the case where the electrostatic capacitance medium 23 is constituted only by the base 23a.

  By the way, as shown to Fig.1 (a), the surface tension of the liquid level of the electrostatic capacitance medium 23 accommodated in the accommodation space C is applied to the inner wall surface of the case 11, the first columnar object 21, and the liquid level. It acts on the second columnar object 22 that is closest. For this reason, the liquid surface of the electrostatic capacitance medium 23 becomes a substantially horizontal state. In other words, by providing the first columnar object 21 and the second columnar object in the accommodation space C, it is possible to always maintain the liquid level of the capacitance medium 23 in a substantially horizontal state. Therefore, when the tilt angle sensor 1 is tilted, a difference occurs in the area of each differential electrode 16a, 16b immersed in the capacitance medium 23, and a difference also occurs in the capacitance of each capacitor. Therefore, the tilt angle of the tilt angle sensor 1 can be reliably obtained based on the difference in capacitance between the capacitors.

  As shown in FIG. 1, a processing substrate 31 is disposed on the outer wall surface of the second wall portion 13 in the case 11. First to third terminal portions 32 a to 32 c are provided on the side surface of the case 11 in the processing substrate 31. The first terminal portion 32a is electrically connected to the terminal portion 16c of the differential electrode 16a via a wire 33a. Similarly, the second terminal portion 32b is electrically connected to the terminal portion 16d of the differential electrode 16b via a wire 33b. The third terminal portion 32c is electrically connected to the terminal portions 15c and 15d of the common electrodes 15a and 15b via a wire 33c.

  The processing substrate 31 converts the difference between the capacitances of the first and second capacitors (= “capacitance of the first capacitor” − “capacitance of the second capacitor”) into a voltage difference, and A detection circuit for outputting the detection voltage Vout based on the voltage difference to the outside is provided. Specifically, as shown in FIG. 4, the detection circuit outputs a predetermined reference voltage Vs as the detection voltage Vout when the tilt angle sensor 1 is in a horizontal state, that is, when the voltage difference is “0”. ing. On the other hand, for example, when the capacitance of the first capacitor increases and the capacitance of the second capacitor decreases due to the inclination of the inclination angle sensor 1, the voltage difference shifts to the plus side. In this case, the detection circuit outputs a voltage (Vs + ΔV) obtained by adding the transition voltage ΔV to the reference voltage Vs as the detection voltage Vout. For example, when the capacitance of the first capacitor decreases and the capacitance of the second capacitor increases, the voltage difference shifts to the negative side. In this case, the detection circuit outputs a voltage (Vs−ΔV) obtained by subtracting the transition voltage ΔV from the reference voltage Vs as the detection voltage Vout.

As shown in FIG. 1, the case 11 and the processing substrate 31 are sealed by a package material 34 made of synthetic resin or ceramic.
Next, the operation of the tilt angle sensor 1 configured as described above will be described.

  First, when the tilt angle sensor 1 is held horizontally, the areas of the portions immersed in the capacitance medium 23 in the common electrodes 15a and 15b and the differential electrodes 16a and 16b are substantially equal as described above. For this reason, the capacitance of the first capacitor and the capacitance of the second capacitor are substantially equal, and the voltage difference based on the difference between the capacitances of the two capacitors is substantially “0”. In this case, the tilt angle sensor 1 outputs the reference voltage Vs as the detection voltage Vout.

  On the other hand, as shown in FIG. 5, for example, when the inclination angle sensor 1 is inclined from the horizontal state by a predetermined angle θ (in the figure, θ = 30 °) in the left direction shown in FIG. While the capacitance of the second capacitor decreases. For this reason, the difference between the capacitance of the first capacitor and the capacitance of the second capacitor shifts to the plus side by a shift amount proportional to the tilt angle θ. Therefore, the voltage difference based on the difference in capacitance between both capacitors shifts to the plus side. As a result, the tilt angle sensor 1 outputs a voltage (Vs + ΔVθ) obtained by adding the transition voltage ΔVθ proportional to the tilt angle θ to the reference voltage Vs as the detection voltage Vout. When the tilt angle sensor 1 is tilted from the horizontal state to the right by a predetermined angle θ, the voltage difference based on the difference in capacitance between both capacitors shifts to the minus side. As a result, the tilt angle sensor 1 outputs a voltage (Vs−ΔVθ) obtained by subtracting the transition voltage ΔVθ proportional to the tilt angle θ from the reference voltage Vs as the detection voltage Vout.

  Therefore, the value of the detection voltage Vout output from the inclination angle sensor 1 changes according to the inclination angle, and the inclination angle of the inclination angle sensor 1 can be obtained based on the detection voltage Vout. That is, the tilt angle sensor 1 outputs the tilt angle as the detection voltage Vout.

<Examples and Comparative Examples>
Next, an example embodying the present embodiment and a comparative example will be introduced.
(Examples 1-4)
In Example 1, zirconia (ZrO ₂ ) having an average particle diameter of 200 nm was mixed in a carbinol-modified silicone oil having both ends to form a capacitance medium 23.

In Example 2, zirconia (ZrO ₂ ) having an average particle diameter of 200 nm was mixed in a double-terminal amino-modified silicone oil to obtain a capacitance medium 23.
In Example 3, titanium oxide (TiO ₂ ) having an average particle diameter of 200 nm was mixed with the carbinol-modified silicone oil at both ends to form the capacitance medium 23.

In Example 2, titanium oxide (TiO ₂ ) having an average particle diameter of 200 nm was mixed in the amino-modified silicone oil at both ends to form the electrostatic capacity medium 23.
In each of Examples 1 to 4, the content of zirconia or titanium oxide in the capacitance medium 23 was 5%.

(Comparative Examples 1 and 2)
In Comparative Example 1, zirconia (ZrO ₂ ) having an average particle diameter of 200 nm was mixed with dimethyl silicone oil to obtain a capacitance medium 23.

In Comparative Example 2, titanium oxide (TiO ₂ ) having an average particle diameter of 200 nm was mixed with dimethyl silicone oil to obtain a capacitance medium 23.
In Comparative Examples 1 and 2, the content of zirconia or titanium oxide in the capacitance medium 23 was 5%.

(Comparative test method and results)
The electrostatic capacity medium 23 was stirred to uniformly disperse the fine particles 23b in the base 23a, and then the dispersion stability of the fine particles 23b was measured by allowing the electrostatic capacity medium 23 to stand in a room temperature environment. Specifically, the time (dispersion maintenance time) from when the fine particles 23b were dispersed in the base 23a to settling was measured, and the longer the time, the higher the dispersion stability. The state in which the fine particles 23b are uniformly mixed in the base 23a is determined as the “dispersed state”, and when the supernatant is generated in the capacitance medium 23, it is determined as the “sedimented state”, and the sedimented state is obtained. The time until was measured as the dispersion maintenance time. The results of dispersion stability in each example and comparative example are shown in Table 1. In the column of “Evaluation” in Table 1, ◎: 96 hours or more, ○: 12 hours or more to less than 96 hours, Δ: 3 hours or more to less than 12 hours, ×: 3 hours Shown as less than.

その結果、比較例１では分散維持時間が３時間未満であったのに対し、実施例１では９６時間以上、実施例２，３では１２時間以上、実施例４では３時間以上の分散維持時間となった。よって、実施例１〜４の何れの場合においても高い分散安定性が得られた。すなわち、これら実施例１〜４からも明らかなように、基剤２３ａとして変性シリコーンオイルを用いると、微粒子２３ｂの分散性が向上する。特に、基剤２３ａとしてカルビノール変性シリコーンオイルを用いた場合や、微粒子２３ｂとしてジルコニアを用いた場合に、高い分散安定性が得られた。そして、カルビノール変性シリコーンオイルにジルコニアを分散させた場合に、最も高い分散安定性が得られることが判った。こうした結果から、基剤２３ａとして反応性シリコーンオイルを用いると、微粒子２３ｂの分散安定性が飛躍的に向上すると推測される。

As a result, while the dispersion maintenance time was less than 3 hours in Comparative Example 1, the dispersion maintenance time was 96 hours or more in Example 1, 12 hours or more in Examples 2 and 3, and 3 hours or more in Example 4. It became. Therefore, high dispersion stability was obtained in any of Examples 1 to 4. That is, as is clear from these Examples 1 to 4, when modified silicone oil is used as the base 23a, the dispersibility of the fine particles 23b is improved. In particular, when a carbinol-modified silicone oil was used as the base 23a, or when zirconia was used as the fine particles 23b, high dispersion stability was obtained. It was found that the highest dispersion stability was obtained when zirconia was dispersed in carbinol-modified silicone oil. From these results, it is estimated that when reactive silicone oil is used as the base 23a, the dispersion stability of the fine particles 23b is dramatically improved.

Therefore, according to the present embodiment, the following effects can be obtained.
(1) The modified silicone oil is used as the base 23a, and fine particles having a dielectric constant higher than that of the modified silicone oil are mixed into the base 23a to form the capacitive medium 23, whereby the dielectric of the capacitive medium 23 is obtained. The rate can be increased reliably and easily. Further, by using the modified silicone oil as the base 23a, the heat resistance, cold resistance, oxidation resistance and the like of the capacitance medium 23 are maintained, so that the performance deterioration of the capacitance medium 23 can be suppressed. it can. In addition, since the interfacial tension of the base 23a with respect to the fine particles 23b can be lowered by using the modified silicone oil as the base 23a, the dispersion stability of the fine particles 23b mixed in the base 23a can be improved. Therefore, variations in the dielectric constant of the capacitance medium 23 can be made difficult to occur.

  (2) The fine particles 23b are set to a size capable of Brownian motion within the base 23a. In particular, in the present embodiment, the size of the fine particles 23b is nanoscale, so that the Brownian motion is surely generated in the base 23a. Therefore, even if an external force for stirring the fine particles 23b is not applied to the base 23a, the fine particles 23b are uniformly and uniformly diffused into the base 23a. Therefore, it is possible to more reliably suppress the disadvantage that the dielectric constant varies for each part of the capacitance medium 23.

(3) By using reactive silicone oil as the base 23a of the capacitance medium 23, the dispersion stability of the fine particles 23b in the base 23a can be further improved.
(4) Since the dielectric constant of the capacitance medium 23 can be reliably and easily increased, a high capacitance can be ensured even if the capacitance type tilt angle sensor 1 is reduced in size. Detection reliability, detection resolution, etc. are not reduced. Moreover, since the heat resistance, cold resistance, oxidation resistance, etc. of the electrostatic capacity medium 23 are maintained by using the modified silicone oil as the base 23a, it is possible to suppress the performance deterioration of the electrostatic capacity medium 23. . Moreover, since the high dielectric constant of the capacitance medium 23 can be secured by using the modified silicone oil as the base 23a, it is possible to reduce the size of the tilt sensor 1 while preventing the performance deterioration and the performance deterioration. it can.

In addition, you may change embodiment of this invention as follows.
The electrostatic capacity medium 23 is not limited to the tilt angle sensor 1 and may be used for, for example, a capacitor or a chemical battery.

  In the above embodiment, the fine particles 23b are not limited to a particle size of several tens of nanometers, for example, within a range of several nanometers to several hundreds of nanometers as long as the fine particles 23b can float by Brownian motion in the base 23a. It may be a nanoscale. In addition, the fine particles 23b may be formed in a microscale size having a particle size of several μm to tens of μm as long as the fine particles 23b can float in the base 23a. In addition, when the particle diameter is formed within the range of several nm to 100 nm, the inventor of the present application has confirmed that the fine particles 23b are surely floated by Brownian motion in the base 23a.

The mixing rate of the fine particles 23b with respect to the base 23a is suitably about 3 to 10%, and more preferably about 5 to 8%.
Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the embodiment described above are listed below.

(1) In the electrostatic capacity medium, the base is a side chain type modified silicone oil. According to the invention described in this technical idea (1), the dispersion stability of the fine particles with respect to the base can be further improved.

(2) In the electrostatic capacity medium, the size of the fine particles is set to a nanoscale within a range of several nanometers to several hundred nanometers. According to the invention described in the technical idea (2), the fine particles can be reliably suspended in the base.

(A) is a front view which shows a part of electrostatic capacitance type inclination angle sensor of one Embodiment of this invention as a cross section, (b) is sectional drawing of the electrostatic capacitance type inclination angle sensor of the same embodiment. The perspective view which shows the common electrode and differential electrode of the embodiment. Explanatory drawing which shows the detail of the electrostatic capacitance medium of the embodiment. The output characteristic figure of the electrostatic capacitance type inclination-angle sensor of the embodiment. The front view which shows the inclination state of the electrostatic capacitance type inclination angle sensor of the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Capacitance type inclination-angle sensor, 11 ... Case, 15a, 15b ... Common electrode, 16a, 16b ... Differential electrode, 23 ... Capacitance medium, 23a ... Base, 23b ... Fine particle.

Claims (3)

A modified silicone oil consisting of a liquid base, the base Ri Na are mixed a high dielectric constant fine particles than the fine particles is set to floatable size by Brownian motion within the base A capacitance medium characterized by the above. The capacitive medium according to claim 1, wherein the modified silicone oil is a reactive silicone oil. The capacitance medium according to claim 1 or claim 2, a case for accommodating the capacitance medium, provided facing the wall surface of the case constitute a capacitor, by a portion that the capacitance medium A capacitance type tilt angle sensor comprising an immersed differential electrode and a common electrode, wherein the capacitance of the capacitor is changed according to the tilt of the case.

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