JP2007309658A

JP2007309658A - Contact pressure sensor

Info

Publication number: JP2007309658A
Application number: JP2006136055A
Authority: JP
Inventors: Jiro Terada; 二郎寺田; Koji Nomura; 幸治野村
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2006-05-16
Filing date: 2006-05-16
Publication date: 2007-11-29

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contact pressure sensor capable of sensing contact pressure with a satisfactory accuracy, even when the surface of an object to be sensed is stained. <P>SOLUTION: The sensor is provided with a substrate 10, a contact pressure sensing element 12 formed on the top surface of this substrate 10, and an oscillating section 14 formed on the undersurface of the substrate 10 to vibrate the sensing element 12. This sensing element 12 is provided for sensing a contact pressure, by sensing electricity generated due to the piezo-electric effect of a first piezoelectric element 16, and an upper sensing electrode 18 and a lower sensing electrode 20 are in the shape of a lattice. A second piezoelectric element 17 is strained, by applying a voltage between an upper oscillating electrode 22 and a lower oscillating electrode 24, and the oscillating section 14 is made to vibrate in fixed directions. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、人間の手足等、検知物の接触圧を検知する接触圧検知センサに関するものである。 The present invention relates to a contact pressure detection sensor for detecting a contact pressure of a detected object such as a human limb.

従来の接触検知センサは、人間の手足等、検知物の接触圧を検知する接触圧検知部を備えており、静電容量の変化に基づき接触圧を検知したり、ダイヤフラム構造であって基板上の圧電体に発生する電荷の変化に基づき接触圧を検知したりするものがある。 A conventional contact detection sensor includes a contact pressure detection unit that detects the contact pressure of a detected object such as a human limb, and detects a contact pressure based on a change in capacitance. Some contact pressures are detected based on a change in electric charge generated in the piezoelectric body.

なお、この出願の発明に関連する先行技術文献情報としては、例えば、特許文献１や特許文献２が知られている。
特開平１１−２４８４１０号公報特開２００４−６９４８１号公報 As prior art document information related to the invention of this application, for example, Patent Document 1 and Patent Document 2 are known.
Japanese Patent Laid-Open No. 11-248410 JP 2004-69481 A

上記従来の構成では、接触圧が付加された際に、静電容量が変化したり、圧電体に発生する電荷が変化したりするが、これらの変化は特に接触圧が付加された瞬間に発生するもので、接触の印加時間の長さに対応した検知信号を得ることができない。このため、検知感度は、接触圧が付加される瞬間の接触圧検知部と検知物との接触状態に左右されて誤検知されやすく、検知感度を向上することが難しいという問題点を有していた。 In the above conventional configuration, when contact pressure is applied, the capacitance changes or the electric charge generated in the piezoelectric body changes, but these changes occur particularly at the moment when the contact pressure is applied. Therefore, a detection signal corresponding to the length of the contact application time cannot be obtained. For this reason, the detection sensitivity is affected by the contact state between the contact pressure detection unit and the detected object at the moment when the contact pressure is applied, so that it is easy to be erroneously detected, and it is difficult to improve the detection sensitivity. It was.

本発明は上記問題点を解決するもので検知感度を向上した接触圧検知センサを提供することを目的としている。 The present invention has been made to solve the above-described problems, and an object thereof is to provide a contact pressure detection sensor with improved detection sensitivity.

上記目的を達成するために本発明は、互いに対向する電極を有し、前記電極に係る接触圧を検知する接触圧検知部を備え、前記接触圧検知部を振動させる振動部を設けるとともに前記接触圧検知部を振動させた状態で接触圧を検知する構成である。 In order to achieve the above object, the present invention has electrodes that face each other, includes a contact pressure detection unit that detects a contact pressure related to the electrode, and includes a vibrating unit that vibrates the contact pressure detection unit and the contact. It is the structure which detects a contact pressure in the state which vibrated the pressure detection part.

上記構成により、接触圧検知部は検知物に対して、振動部の振動数に同調しながら接触するため、単位時間あたり、検知物には何度も接触圧検知部が接触し、その接触回数分、接触圧の検知が可能となるので検知感度を向上できる。 With the above configuration, the contact pressure detection unit contacts the detected object while synchronizing with the frequency of the vibration unit. Therefore, the contact pressure detection unit contacts the detected object many times per unit time. Therefore, the detection sensitivity can be improved.

以下、本発明の全請求項に記載の発明について図面を参照しながら説明する。 Hereinafter, the invention described in all claims of the present invention will be described with reference to the drawings.

図１は本発明の一実施の形態における接触圧検知センサの斜視図、図２は同接触圧検知センサの断面図、図３は接触圧検知センサの動作状態を示す動作状態図、図４は接触圧と検知信号の関係を示す特性図、図５は同接触圧検知センサの工程図である。 1 is a perspective view of a contact pressure detection sensor according to an embodiment of the present invention, FIG. 2 is a sectional view of the contact pressure detection sensor, FIG. 3 is an operation state diagram showing an operation state of the contact pressure detection sensor, and FIG. FIG. 5 is a process diagram of the contact pressure detection sensor, showing the relationship between the contact pressure and the detection signal.

図１、図２において、本発明の一実施の形態における接触圧検知センサは、基板１０と、この基板１０の上面に形成した接触圧検知部１２と、基板１０の下面に形成し接触圧検知部１２を振動させる振動部１４とを設けている。この接触圧検知部１２は、第１の圧電体１６の圧電効果に起因して発生する電荷を検出して接触圧を検知するものであって、上部検知用電極１８と下部検知用電極２０の間に配置した第１の圧電体１６を有し、外部出力用端子２１に接続されている。特に、上部検知用電極１８および下部検知用電極２０の形状は格子形状にしている。 1 and 2, a contact pressure detection sensor according to an embodiment of the present invention includes a substrate 10, a contact pressure detection unit 12 formed on the upper surface of the substrate 10, and a contact pressure detection formed on the lower surface of the substrate 10. And a vibrating portion 14 for vibrating the portion 12. The contact pressure detection unit 12 detects a contact pressure by detecting electric charges generated due to the piezoelectric effect of the first piezoelectric body 16. The contact pressure detection unit 12 detects the contact pressure, and includes an upper detection electrode 18 and a lower detection electrode 20. The first piezoelectric member 16 disposed therebetween is connected to the external output terminal 21. In particular, the upper detection electrode 18 and the lower detection electrode 20 have a lattice shape.

また、振動部１４は、上部振動用電極２２と下部振動用電極２４との間に配置した第２の圧電体１７を有し、接触圧検知部１２と対向配置させるとともに振動部１４の外形を接触圧検知部１２の電極の外形よりも大きくしている。 The vibration unit 14 includes a second piezoelectric body 17 disposed between the upper vibration electrode 22 and the lower vibration electrode 24. The vibration unit 14 is disposed so as to face the contact pressure detection unit 12 and the outer shape of the vibration unit 14. It is larger than the outer shape of the electrode of the contact pressure detector 12.

さらに、基板１０には下部検知用電極２０の交差部２６と対向する対向部に貫通孔２８を設けるとともに振動部１４の周囲部に溝部３０を形成している。この溝部３０の外側は、この接触圧検知センサを実装する際の台座３２となる。 Further, the substrate 10 is provided with a through hole 28 in a facing portion facing the intersecting portion 26 of the lower detection electrode 20, and a groove portion 30 is formed around the vibrating portion 14. The outside of the groove 30 serves as a base 32 when the contact pressure detection sensor is mounted.

そして、図３に示すように、上部振動用電極２２および下部振動用電極２４に電圧を印加することによって第２の圧電体１７を歪ませ、振動部１４を一定方向（矢印方向）に振動させている。そうすると、この振動部１４による振動に同調して基板１０を介して接触圧検知部１２が振動するとともに、この振動数分だけ検知物３３に接触する。 Then, as shown in FIG. 3, by applying a voltage to the upper vibration electrode 22 and the lower vibration electrode 24, the second piezoelectric body 17 is distorted, and the vibration part 14 is vibrated in a certain direction (arrow direction). ing. Then, the contact pressure detection unit 12 vibrates through the substrate 10 in synchronization with the vibration by the vibration unit 14 and contacts the detected object 33 by this frequency.

この際、検知物３３に対する接触圧検知部１２の接触圧と検知信号の関係は図４に示す通りである。図４の上段に示すように、接触圧が加わった際、従来の接触圧センサでは、図４の中段に示すように、接触圧が加わった瞬間から急激に検知信号の出力が低下するが、上記構成の接触圧センサでは、図４の下段に示すように、接触圧が加わった瞬間から接触圧がなくなるまで、接触圧検知部１２の振動数分だけ検知信号が出力される。 At this time, the relationship between the contact pressure of the contact pressure detector 12 with respect to the detected object 33 and the detection signal is as shown in FIG. As shown in the upper part of FIG. 4, when the contact pressure is applied, in the conventional contact pressure sensor, as shown in the middle part of FIG. 4, the output of the detection signal suddenly decreases from the moment when the contact pressure is applied. In the contact pressure sensor having the above configuration, as shown in the lower part of FIG. 4, detection signals are output for the number of vibrations of the contact pressure detection unit 12 from the moment when the contact pressure is applied until the contact pressure disappears.

上記構成の接触圧検知センサの製造工程は図５に示す通りである。 The manufacturing process of the contact pressure detection sensor having the above configuration is as shown in FIG.

第１に、図５（ａ）に示すように、Ｓｉからなる基板１０を熱酸化させて基板１０の表面にＳｉＯ₂からなる熱酸化膜３４を形成する。 First, as shown in FIG. 5A, the substrate 10 made of Si is thermally oxidized to form a thermal oxide film 34 made of SiO _{2 on} the surface of the substrate 10.

第２に、この熱酸化膜３４を形成した基板１０上には、スパッタにより１００ÅのＴｉ膜を成膜して、そのＴｉ膜上にスパッタにより０．２μｍのＰｔ膜を成膜して、下部検知用電極２０を形成する。 Second, a 100-nm Ti film is formed on the substrate 10 on which the thermal oxide film 34 is formed by sputtering, and a 0.2 μm Pt film is formed on the Ti film by sputtering. The detection electrode 20 is formed.

第３に、下部検知用電極２０上にスパッタにより２．５μｍのチタン酸・ジルコン酸鉛の酸化物（ＰＺＴ）を成膜して第１の圧電体１６を形成する。 Third, a first piezoelectric body 16 is formed by forming a 2.5 μm oxide of titanic acid / lead zirconate (PZT) on the lower detection electrode 20 by sputtering.

第４に、図５（ｂ）に示すように、第１の圧電体１６は、フォトレジスト工法によりウェットエッチングして、格子形状に形成する。 Fourth, as shown in FIG. 5B, the first piezoelectric body 16 is formed in a lattice shape by wet etching using a photoresist method.

第５に、図５（ｃ）に示すように、格子形状の第１の圧電体１６には樹脂を被覆して絶縁体３６を形成する。この際、絶縁体３６の表面と第１の圧電体１６の表面とが同一面になるようにして、第１の圧電体１６の表面が絶縁体３６より露出するようにしている。 Fifthly, as shown in FIG. 5C, the lattice-shaped first piezoelectric body 16 is covered with a resin to form an insulator 36. At this time, the surface of the insulator 36 and the surface of the first piezoelectric body 16 are flush with each other so that the surface of the first piezoelectric body 16 is exposed from the insulator 36.

第６に、図５（ｄ）に示すように、この絶縁体３６より露出した第１の圧電体１６の表面上にスパッタにより１００ÅのＴｉ膜を成膜して、このＴｉ膜上にスパッタにより０．３μｍのＡｕを成膜して、上部検知用電極１８を形成する。この上部検知用電極１８は格子形状に形成している。 Sixth, as shown in FIG. 5D, a 100-thick Ti film is formed on the surface of the first piezoelectric body 16 exposed from the insulator 36 by sputtering, and the Ti film is sputtered on. An upper detection electrode 18 is formed by depositing 0.3 μm Au. The upper detection electrode 18 is formed in a lattice shape.

第７に、基板１０には、格子形状の上部検知用電極１８の交差部２６と対向する対向部に、フォトレジスト工法とドライエッチング加工にて貫通孔２８を形成するとともに、この貫通孔２８を取り囲むように貫通孔２８の最外側に溝部３０を形成している。 Seventh, a through hole 28 is formed in the substrate 10 at a facing portion facing the intersecting portion 26 of the lattice-shaped upper detection electrode 18 by a photoresist method and a dry etching process. A groove portion 30 is formed on the outermost side of the through hole 28 so as to surround it.

第８に、図５（ｅ）に示すように、基板１０の裏面にＡｇからなる上部振動用電極２２を形成し、この上部振動用電極２２の下面に第２の圧電体１７を形成し、この第２の圧電体１７の下面に下部振動用電極２４を形成し、第２の圧電体１７を上部振動用電極２２と下部振動用電極２４で挟んでいる。 Eighth, as shown in FIG. 5E, the upper vibration electrode 22 made of Ag is formed on the back surface of the substrate 10, and the second piezoelectric body 17 is formed on the lower surface of the upper vibration electrode 22. A lower vibration electrode 24 is formed on the lower surface of the second piezoelectric body 17, and the second piezoelectric body 17 is sandwiched between the upper vibration electrode 22 and the lower vibration electrode 24.

上記構成により、接触圧検知部１２は検知物３３に対して、振動部１４の振動数に同調しながら接触するため、単位時間あたり、検知物３３には何度も接触圧検知部１２が接触し、その接触回数分、接触圧の検知が可能となるので検知感度を向上できる。この際、接触圧検知部１２の電極形状を格子形状にしているので、検知物３３が接触圧検知部１２の上部検知用電極１８に接触した際、第１の圧電体１６に付加される圧力が格子形状に沿って局所的に付加されるので、圧力が分散されにくく、その接触状態を感度よく検知できる。 With the above configuration, the contact pressure detection unit 12 contacts the detection object 33 while synchronizing with the frequency of the vibration unit 14, so that the detection pressure 33 contacts the detection object 33 many times per unit time. Since the contact pressure can be detected for the number of times of contact, the detection sensitivity can be improved. At this time, since the electrode shape of the contact pressure detection unit 12 is a lattice shape, the pressure applied to the first piezoelectric body 16 when the detected object 33 contacts the upper detection electrode 18 of the contact pressure detection unit 12. Is locally added along the lattice shape, the pressure is not easily dispersed, and the contact state can be detected with high sensitivity.

特に、互いに対向する上部検知用電極１８と下部検知用電極２０の間に第１の圧電体１６を介在させ、この第１の圧電体１６の圧電効果に起因して発生する電荷を検出して接触圧を検知するので、的確な検知が可能である。 In particular, the first piezoelectric body 16 is interposed between the upper detection electrode 18 and the lower detection electrode 20 facing each other, and charges generated due to the piezoelectric effect of the first piezoelectric body 16 are detected. Since the contact pressure is detected, accurate detection is possible.

また、基板１０には電極の交差部２６と対向する対向部に貫通孔２８を設けているので、基板１０を振動させやすくし、接触圧検知部１２に検知物３３が接触した際、第１の圧電体１６が受ける変位量を大きくして感度を向上できる。 Further, since the substrate 10 is provided with the through hole 28 in the facing portion that faces the intersecting portion 26 of the electrode, the substrate 10 is easily vibrated, and when the detected object 33 comes into contact with the contact pressure detecting portion 12, the first Sensitivity can be improved by increasing the amount of displacement that the piezoelectric body 16 receives.

さらに、振動部１４は基板１０を介して接触圧検知部１２と対向配置させ、かつ、振動部１４の外形を接触圧検知部１２の電極の外形よりも大きくしているので、不要信号を取り込みにくく、感度を向上できる。特に、基板１０には振動部１４の周囲部に溝部３０を形成しているので、この溝部３０を境界として不要信号を取り込みにくくなり感度を向上できる。 Further, since the vibration unit 14 is disposed opposite to the contact pressure detection unit 12 via the substrate 10 and the outer shape of the vibration unit 14 is larger than the outer shape of the electrode of the contact pressure detection unit 12, an unnecessary signal is captured. It is difficult to improve sensitivity. In particular, since the groove portion 30 is formed in the peripheral portion of the vibration portion 14 in the substrate 10, it is difficult to capture unnecessary signals with the groove portion 30 as a boundary, and the sensitivity can be improved.

なお、接触圧検知部１２は基板１０上に形成し、電極の交差部２６と対向する対向部における基板１０の厚みを薄くしても、振動部１４による振動をさせやすくし、接触圧検知部１２に検知物３３が接触した際、第１の圧電体１６が受ける変位量を大きくして感度を向上できる。 Note that the contact pressure detection unit 12 is formed on the substrate 10, and even if the thickness of the substrate 10 at the facing portion facing the electrode crossing portion 26 is reduced, the contact pressure detection unit 12 can easily be vibrated by the vibration unit 14. When the detected object 33 contacts 12, the amount of displacement received by the first piezoelectric body 16 can be increased to improve the sensitivity.

また、図６に示すように、上部検知用電極１８上に突起部３８を設ければ、検知物３３の表面が湿潤していたとしても、検知感度を劣化させない。一般的には湿潤層が約１０μｍ以下なので、突起部３８の突起長（Ｈ）が約１０μｍを超えるものであればよい。ただし、突起長が２０μｍを超えると接触圧検知部１２の振動に負荷がかかり、振幅に悪影響を与えるので、２０μｍ以下が望ましい。 Further, as shown in FIG. 6, if the protrusion 38 is provided on the upper detection electrode 18, even if the surface of the detection object 33 is wet, the detection sensitivity is not deteriorated. In general, since the wet layer is about 10 μm or less, the protrusion length (H) of the protrusion 38 may be more than about 10 μm. However, if the protrusion length exceeds 20 μm, a load is applied to the vibration of the contact pressure detection unit 12 and adversely affects the amplitude.

さらに、上部検知用電極１８と下部検知用電極２０の間に第１の圧電体１６を介在させ、圧電効果に起因して発生する電荷を検出して接触圧を検知することに替え、上部検知用電極１８と下部検知用電極２０の間の静電容量の変化を検出して接触圧を検知してもよい。 Further, the first piezoelectric body 16 is interposed between the upper detection electrode 18 and the lower detection electrode 20 to detect the contact pressure by detecting the electric charge generated due to the piezoelectric effect. The contact pressure may be detected by detecting a change in capacitance between the working electrode 18 and the lower sensing electrode 20.

以上のように本発明にかかる接触圧検知センサは、検知物の表面が汚れていた場合でも精度よく接触圧を検知でき、各種センサ機器に適用できる。 As described above, the contact pressure detection sensor according to the present invention can accurately detect the contact pressure even when the surface of the detected object is dirty, and can be applied to various sensor devices.

本発明の一実施の形態における接触圧検知センサの斜視図The perspective view of the contact pressure detection sensor in one embodiment of this invention 同接触圧検知センサの断面図Sectional view of the contact pressure detection sensor 同接触圧検知センサの動作状態を示す動作状態図Operation state diagram showing the operation state of the contact pressure detection sensor 接触圧と検知信号の関係を示す特性図Characteristic diagram showing the relationship between contact pressure and detection signal 同接触圧検知センサの工程図Process diagram of the contact pressure detection sensor 本発明の他の実施の形態における接触圧検知センサの断面図Sectional drawing of the contact pressure detection sensor in other embodiment of this invention

符号の説明Explanation of symbols

１０基板
１２接触圧検知部
１４振動部
１６第１の圧電体
１７第２の圧電体
１８上部検知用電極
２０下部検知用電極
２１外部出力用端子
２２上部振動用電極
２４下部振動用電極
２６交差部
２８貫通孔
３０溝部
３２台座
３３検知物
３４熱酸化膜
３６絶縁体
３８突起部 DESCRIPTION OF SYMBOLS 10 Board | substrate 12 Contact pressure detection part 14 Vibrating part 16 1st piezoelectric material 17 2nd piezoelectric material 18 Upper detection electrode 20 Lower detection electrode 21 External output terminal 22 Upper vibration electrode 24 Lower vibration electrode 26 Intersection 28 Through-hole 30 Groove part 32 Base 33 Detected object 34 Thermal oxide film 36 Insulator 38 Protrusion part

Claims

互いに対向する電極を有し、前記電極に接触し付加される接触圧を検知する接触圧検知部を備え、前記接触圧検知部を振動させる振動部を設けるとともに前記接触圧検知部を振動させた状態で接触圧を検知する接触圧検知センサ。 A contact pressure detection unit that includes electrodes facing each other and that detects a contact pressure that is applied by contact with the electrodes is provided, and a vibration unit that vibrates the contact pressure detection unit is provided and the contact pressure detection unit is vibrated. Contact pressure detection sensor that detects contact pressure in the state.

前記電極の形状を格子形状にした請求項１記載の接触圧検知センサ。 The contact pressure detection sensor according to claim 1, wherein the electrode has a lattice shape.

互いに対向する前記電極の間に圧電体を介在させ、前記圧電体の圧電効果に起因して発生する電荷を検出した接触圧を検知する請求項１記載の接触圧検知センサ。 The contact pressure detection sensor according to claim 1, wherein a piezoelectric body is interposed between the electrodes facing each other to detect a contact pressure in which an electric charge generated due to the piezoelectric effect of the piezoelectric body is detected.

互いに対向する前記電極間の静電容量を検出して接触圧を検知する請求項１記載の接触圧検知センサ。 The contact pressure detection sensor according to claim 1, wherein the contact pressure is detected by detecting capacitance between the electrodes facing each other.

前記接触圧検知部は基板上に形成し、前記電極の交差部と対向する対向部における前記基板の厚みを薄くした請求項１記載の接触圧検知センサ。 The contact pressure detection sensor according to claim 1, wherein the contact pressure detection unit is formed on a substrate, and the thickness of the substrate at a facing portion facing the intersecting portion of the electrodes is reduced.

前記接触圧検知部は基板上に形成し、前記基板には前記電極の交差部と対向する対向部に貫通孔を設けた請求項１記載の接触圧検知センサ。 The contact pressure detection sensor according to claim 1, wherein the contact pressure detection unit is formed on a substrate, and the substrate is provided with a through hole in a facing portion that faces the intersecting portion of the electrodes.

前記接触圧検知部は基板上に形成し、前記振動部は前記基板を介して前記接触圧検知部と対向配置させ、かつ、前記振動部の外形を前記接触圧検知部の電極の外形よりも大きくした請求項１記載の接触圧検知センサ。 The contact pressure detection unit is formed on a substrate, the vibration unit is disposed opposite to the contact pressure detection unit via the substrate, and an outer shape of the vibration unit is more than an outer shape of an electrode of the contact pressure detection unit. The contact pressure detection sensor according to claim 1, which is enlarged.

前記接触圧検知部は基板上に形成し、前記基板には前記振動部の周囲部に溝部を形成した請求項１記載の接触圧検知センサ。 The contact pressure detection sensor according to claim 1, wherein the contact pressure detection unit is formed on a substrate, and a groove is formed around the vibration unit on the substrate.

前記電極上に突起部を設けた請求項１記載の接触圧検知センサ。 The contact pressure detection sensor according to claim 1, wherein a protrusion is provided on the electrode.