JP4785247B2

JP4785247B2 - Ultrasonic contact position detector

Info

Publication number: JP4785247B2
Application number: JP2000384622A
Authority: JP
Inventors: 耕司戸田
Original assignee: 耕司戸田
Priority date: 2000-12-19
Filing date: 2000-12-19
Publication date: 2011-10-05
Anticipated expiration: 2020-12-19
Also published as: JP2002182843A

Description

【０００１】
【発明の属する技術分野】
本発明は、弾性表面波が伝搬された非圧電板に接触すると、その接触位置が判別される超音波接触位置検出装置に関する。
【０００２】
【従来の技術】
従来のタッチパネルは、くさび型トランスデューサや圧電薄膜トランスデューサを含むものが一般的であった。くさび型トランスデューサは非圧電板に間接的に弾性振動を起こさせる機能を有し、圧電薄膜トランスデューサは非圧電板に直接弾性振動を起こさせる機能を有する。いずれにせよこのような従来のタッチパネルは、非圧電板上を接触することにより非圧電板上の超音波が消失して出力電気信号が検出されなくなるということを利用したもので、出力電気信号が検出されなくなった出力用トランスデューサの配置から接触位置を判別している。従って、従来のタッチパネルは、常にすべての入力用トランスデューサを駆動させておく必要があることから、駆動電圧や消費電力に問題を有するだけでなく、複雑な回路構成を必要とする。さらに、従来のタッチパネルは、液晶と接触する非圧電板に直接超音波を励振させることが困難であった。
【０００３】
【発明が解決しようとする課題】
本発明の目的は、非圧電板の一方の端面を接触することにより現れる遅延電気信号を検出することにより接触位置を高感度で判別できる超音波接触位置検出装置を提供することにある。
また本発明のさらなる目的は、低電圧および低消費電力の自励発振駆動が可能で、回路構成が簡単で、接触に対する応答速度が速く、大量生産が可能で、小型軽量で、耐久性に優れ、液晶を非圧電板のもう一方の端面に接触させることが可能な超音波接触位置検出装置を提供することにある。
【０００４】
【課題を解決するための手段】
請求項１に記載の超音波接触位置検出装置は、非圧電板と、第１および第２超音波伝搬手段と、信号分析器から成る超音波接触位置検出装置であって、前記第１超音波伝搬手段は少なくとも２つの入力用すだれ状電極Txi (i=1, 2,…, m)と、少なくとも２つの電極群Gxi (i=1, 2,…, m)と、第１および第２圧電基板と、少なくとも２つの端子Uxj (j=1, 2,…, n)から成り、前記電極群Gxiの隣り合う２つの一方は少なくとも２つの出力用すだれ状電極Rxaj (j=1, 2,…, n)から成り、もう一方は少なくとも２つの出力用すだれ状電極Rxbj (j=1, 2,…, n)から成り、前記出力用すだれ状電極RxajおよびRxbjは、電極指の方向が互いに逆であり、前記端子Uxjは、前記出力用すだれ状電極Rxajにそれぞれ接続されるとともに、前記出力用すだれ状電極Rxbjにそれぞれ接続され、前記第２超音波伝搬手段は少なくとも２つの入力用すだれ状電極Tyi (i=1, 2,…, m)と、少なくとも２つの電極群Gyi (i=1, 2,…, m)と、第３および第４圧電基板と、少なくとも２つの端子Uyj (j=1, 2,…, n)から成り、前記電極群Gyiの隣り合う２つの一方は少なくとも２つの出力用すだれ状電極Ryaj (j=1, 2,…, n)から成り、もう一方は少なくとも２つの出力用すだれ状電極Rybj (j=1, 2,…, n)から成り、前記出力用すだれ状電極RyajおよびRybjは、電極指の方向が互いに逆であり、前記端子Uyjは、前記出力用すだれ状電極Ryajにそれぞれ接続されるとともに、前記出力用すだれ状電極Rybjにそれぞれ接続され、前記入力用すだれ状電極Txi、前記電極群Gxi、前記入力用すだれ状電極Tyiおよび前記電極群Gyiは前記非圧電板の上端面の第１、第２、第３および第４縁部にそれぞれ設けられ、前記第１、第２、第３および第４圧電基板は、前記入力用すだれ状電極Txi、前記電極群Gxi、前記入力用すだれ状電極Tyiおよび前記電極群Gyiの上にそれぞれ設けられ、前記信号分析器は前記端子UxjおよびUyjと接続され、前記入力用すだれ状電極Txiの隣り合う２つに第１入力電気信号が印加されることにより、前記第１圧電基板に第１弾性表面波が励振され、前記第１弾性表面波は、前記非圧電板の前記上端面を介して前記第２圧電基板に伝搬され、前記出力用すだれ状電極RxajおよびRxbjの各々において第１出力電気信号に変換され、前記入力用すだれ状電極Tyiの隣り合う２つに第２入力電気信号が印加されることにより、前記第３圧電基板に第２弾性表面波が励振され、前記第２弾性表面波は、前記非圧電板の前記上端面を介して前記第４圧電基板に伝搬され、前記出力用すだれ状電極RyajおよびRybjの各々において第２出力電気信号に変換され、前記非圧電板の前記上端面を接触することにより、前記端子Uxjの１つに第１遅延電気信号が連続して２回現われるとともに、前記端子Uyjの１つに第２遅延電気信号が連続して２回現われ、前記第１および第２遅延電気信号は前記信号分析器によって検出され、前記第１遅延電気信号が連続して２回現れたときに前記第１入力電気信号が連続して２回印加されていたのは前記入力用すだれ状電極Txiのうちのどれであるかを検出すること、および前記第２遅延電気信号が連続して２回現れたときに前記第２入力電気信号が連続して２回印加されていたのは前記入力用すだれ状電極Tyiのうちのどれであるかを検出することにより、前記非圧電板の前記上端面における接触位置が判別される。
【０００５】
請求項２に記載の超音波接触位置検出装置では、前記第１、第２、第３および第４圧電基板が一体化されて１つの窓枠構造が形成される。
【０００６】
請求項３に記載の超音波接触位置検出装置は、前記第１、第２、第３および第４圧電基板が圧電セラミックで成り、前記圧電セラミックの分極軸の方向はその厚さ方向と平行である。
【０００７】
請求項４に記載の超音波接触位置検出装置は、前記非圧電板が透明な材質で成る。
【０００８】
請求項５に記載の超音波接触位置検出装置は、前記第１、第２、第３および第４圧電基板の厚さが前記入力用すだれ状電極TxiおよびTyiの電極周期長よりも小さく、前記非圧電板の厚さが前記電極周期長の３倍よりも大きい。
【０００９】
請求項６に記載の超音波接触位置検出装置は、前記非圧電板自身に伝搬する弾性表面波の位相速度が前記第１、第２、第３および第４圧電基板自身に伝搬する弾性表面波の位相速度よりも速い。
【００１０】
請求項７に記載の超音波接触位置検出装置では、前記非圧電板の下端面にもう一つの非圧電板が備えられ、前記非圧電板と前記もう一つの非圧電板との間に液晶が満たされている。
【００１１】
請求項８に記載の超音波接触位置検出装置では、前記信号分析器と、前記入力用すだれ状電極TxiおよびTyiとの間に増幅器が備えられている。
【００１２】
請求項９に記載の超音波接触位置検出装置では、前記入力用すだれ状電極TxiおよびTyiにそれぞれ接続する第１および第２スイッチが備えられている。
【００１３】
【発明の実施の形態】
本発明の超音波接触位置検出装置は非圧電板と、第１および第２超音波伝搬手段と、信号分析器と、増幅器から成る簡単な構造を有する。第１超音波伝搬手段は少なくとも２つの入力用すだれ状電極Txi (i=1, 2,…, m)と、少なくとも２つの電極群Gxi (i=1, 2,…, m)と、第１および第２圧電基板と、少なくとも２つの端子Uxj (j=1, 2,…, n)から成る。電極群Gxiの隣り合う２つの一方は少なくとも２つの出力用すだれ状電極Rxaj (j=1, 2,…, n)から成り、もう一方は少なくとも２つの出力用すだれ状電極Rxbj (j=1, 2,…, n)から成る。出力用すだれ状電極RxajおよびRxbjは、電極指の方向が互いに逆である。端子Uxjは、出力用すだれ状電極Rxajにそれぞれ接続されるとともに、出力用すだれ状電極Rxbjにそれぞれ接続されている。第２超音波伝搬手段は少なくとも２つの入力用すだれ状電極Tyi (i=1, 2,…, m)と、少なくとも２つの電極群Gyi (i=1, 2,…, m)と、第３および第４圧電基板と、少なくとも２つの端子Uyj (j=1, 2,…, n)から成る。電極群Gyiの隣り合う２つの一方は少なくとも２つの出力用すだれ状電極Ryaj (j=1, 2,…, n)から成り、もう一方は少なくとも２つの出力用すだれ状電極Rybj (j=1, 2,…, n)から成る。出力用すだれ状電極RyajおよびRybjは、電極指の方向が互いに逆である。端子Uyjは、出力用すだれ状電極Ryajにそれぞれ接続されるとともに、出力用すだれ状電極Rybjにそれぞれ接続されている。入力用すだれ状電極Txi、電極群Gxi、入力用すだれ状電極Tyiおよび電極群Gyiは非圧電板の上端面の第１、第２、第３および第４縁部にそれぞれ設けられている。第１、第２、第３および第４圧電基板は、入力用すだれ状電極Txi、電極群Gxi、入力用すだれ状電極Tyiおよび電極群Gyiの上にそれぞれ設けられている。信号分析器は端子UxjおよびUyjと接続されている。
【００１４】
本発明の超音波接触位置検出装置において、もしも第１入力電気信号が入力用すだれ状電極Txiの隣り合う２つに同時に印加されると、第１圧電基板に第１弾性表面波が励振される。このとき、第１圧電基板が圧電セラミックで成り、その圧電セラミックの分極軸の方向がその厚さ方向と平行であることから、第１圧電基板には第１弾性表面波が効率よく励振される。さらに、もしも第１弾性表面波の位相速度が非圧電板自身を伝搬する弾性表面波のレイリー波の位相速度とほぼ等しい場合には、第１入力電気信号が高率よく第１弾性表面波に変換される。第１弾性表面波は、非圧電板の上端面を伝わって、非圧電板の内部に漏洩されることなく第２圧電基板に伝搬される。第１弾性表面波が非圧電板の内部に漏洩されないのは、第１に、第１圧電基板の厚さが入力用すだれ状電極Txiの電極周期長よりも小さいこと、第２に、非圧電板の厚さが入力用すだれ状電極Txiの電極周期長の３倍よりも大きいこと、そして第３に、非圧電板自身を伝搬する第１弾性表面波の位相速度が第１圧電基板自身を伝搬する第１弾性表面波の位相速度よりも大きいことに因る。第２圧電基板に伝搬された第１弾性表面波は、出力用すだれ状電極RxajおよびRxbjの各々において第１出力電気信号に変換される。このとき、出力用すだれ状電極Rxajでの第１出力電気信号と、出力用すだれ状電極Rxbjでの第１出力電気信号とでは互いに位相が逆転している。従って、すべての端子Uxjに電気信号が現れることはない。このようにして、入力用すだれ状電極Txiと電極群Gxiの間に全部で（i×j）個の第１弾性表面波伝搬路が形成される。同様にして、もしも第２入力電気信号が入力用すだれ状電極Tyiの隣り合う２つに同時に印加されると、第３圧電基板に第２弾性表面波が励振される。第２弾性表面波は、非圧電板の前記上端面を介して第４圧電基板に伝搬され、出力用すだれ状電極RyajおよびRybjの各々において第２出力電気信号に変換される。このようにして、入力用すだれ状電極Tyiと電極群Gyiの間に全部で（i×j）個の第２弾性表面波伝搬路が形成される。
【００１５】
もしも非圧電板の上端面のどこにも接触しなければ、端子UxjおよびUyjのどこにも遅延電気信号は現れない。しかしながら、非圧電板の上端面のどこかに接触することにより、端子Uxjの１つに第１遅延電気信号が連続して２回現われ、端子Uyjの１つに第２遅延電気信号が連続して２回現れる。別の言葉で言えば、第１入力電気信号が入力用すだれ状電極Txiの１つに連続して２回印加されたときに第１遅延電気信号が端子Uxjの１つに連続して２回現れ、また、第２入力電気信号が入力用すだれ状電極Tyiの１つに連続して２回印加されたときに第２遅延電気信号が端子Uyjの１つに連続して２回現れる。このようにして、端子Uxjの１つに第１遅延電気信号が連続して２回現われたときに第１入力電気信号が連続して２回印加されていたのは入力用すだれ状電極Txiのうちのどれであるか、また、端子Uyjの１つに第２遅延電気信号が連続して２回現れたときに第２入力電気信号が連続して２回印加されていたのは入力用すだれ状電極Tyiのうちのどれであるかを検出することにより、非圧電板の上端面における接触位置を判別することが可能になる。
【００１６】
本発明の超音波接触位置検出装置では、第１、第２、第３および第４圧電基板が一体化されて１つの窓枠構造となることが可能である。このような構造を採用することにより、製造工程を簡略化することができる。
【００１７】
本発明の超音波接触位置検出装置では、非圧電板の下端面にもう一つの非圧電板が備えられ、これら２つの非圧電板の間に液晶が満たされた構造が可能である。このような構造は、液晶のディスプレイとしての機能と一体化させることを可能にする。
【００１８】
本発明の超音波接触位置検出装置では、信号分析器と、入力用すだれ状電極TxiおよびTyiとの間に増幅器が備えられた構造が可能である。このような構造を採用することにより、自励発振型の超音波タッチパネルを形成することが可能になる。従って、回路構成が簡単になり、低電圧で低消費電力駆動が可能となる。
【００１９】
本発明の超音波接触位置検出装置では、入力用すだれ状電極TxiおよびTyiにそれぞれ接続する第１および第２スイッチが備えられた構造が可能である。このような構造を採用することにより、回路構成を簡単にできる。
【００２０】
【実施例】
図１は本発明の超音波接触位置検出装置に含まれるパネル部の一実施例を示す平面図である。超音波接触位置検出装置は第１および第２超音波伝搬手段、非圧電板１、液晶２、もう一つの非圧電板３、信号分析器４、増幅器５、第１スイッチ６および第２スイッチ７から成る。第１超音波伝搬手段は第１圧電基板８、第２圧電基板９、入力用すだれ状電極Tx1, Tx2, Tx3, Tx4およびTx5、電極群Gx1, Gx2, Gx3, Gx4およびGx5、そして端子Ux1, Ux2およびUx3から成る。電極群Gx1, Gx3およびGx5の各々は、出力用すだれ状電極Rxa1, Rxa2およびRxa3から成る。電極群Gx2およびGx4の各々は、出力用すだれ状電極Rxb1, Rxb2およびRxb3から成る。第２超音波伝搬手段は第３圧電基板１０、第４圧電基板１１、入力用すだれ状電極Ty1, Ty2, Ty3, Ty4およびTy5、電極群Gy1, Gy2, Gy3, Gy4およびGy5、そして端子Uy1, Uy2およびUy3から成る。電極群Gy1, Gy3,およびGy5の各々は、出力用すだれ状電極Rya1, Rya2およびRya3から成る。電極群Gy2およびGy4の各々は、出力用すだれ状電極Ryb1, Ryb2およびRyb3から成る。入力用すだれ状電極Tx1, Tx2, Tx3, Tx4およびTx5、電極群Gx1, Gx2, Gx3, Gx4およびGx5、入力用すだれ状電極Ty1, Ty2, Ty3, Ty4およびTy5、電極群Gy1, Gy2, Gy3, Gy4およびGy5は、非圧電板１の上端面の第１、第２、第３および第４縁部にそれぞれ設けられている。第１圧電基板８は入力用すだれ状電極Tx1, Tx2, Tx3, Tx4およびTx5の上に設けられ、第２圧電基板９は電極群Gx1, Gx2, Gx3, Gx4およびGx5の上に設けられ、第３圧電基板１０は入力用すだれ状電極Ty1, Ty2, Ty3, Ty4およびTy5の上に設けられ、第４圧電基板１１は電極群Gy1, Gy2, Gy3, Gy4およびGy5の上に設けられている。このとき、第１圧電基板８、第２圧電基板９、第３圧電基板１０および第４圧電基板１１の代わりに、それらが一体化されることにより形成される１つの窓枠構造型の圧電基板を使用することができる。非圧電板１、液晶２、非圧電板３、第１圧電基板８、第２圧電基板９、第３圧電基板１０、第４圧電基板１１、入力用すだれ状電極Tx1, Tx2, Tx3, Tx4, Tx5, Ty1, Ty2, Ty3, Ty4およびTy5、電極群Gx1, Gx2, Gx3, Gx4, Gx5, Gy1, Gy2, Gy3, Gy4およびGy5はパネル部を形成する。図１では第１圧電基板８、第２圧電基板９、第３圧電基板１０および第４圧電基板１１は描かれていない。非圧電板１は透明なガラス板で成り、非圧電板１自身を伝搬する弾性表面波の位相速度は第１圧電基板８自身を伝搬する弾性表面波の位相速度よりも速い。入力用すだれ状電極Tx1, Tx2, Tx3, Tx4, Tx5, Ty1, Ty2, Ty3, Ty4およびTy5、電極群Gx1, Gx2, Gx3, Gx4, Gx5, Gy1, Gy2, Gy3, Gy4およびGy5は、それぞれアルミニウム薄膜で成る。第１圧電基板８、第２圧電基板９、第３圧電基板１０および第４圧電基板１１は圧電セラミックで成り、その圧電セラミックの分極軸の方向はその厚さ方向と平行である。
【００２１】
図２はパネル部の部分拡大平面図である。図２では非圧電板１に設けられた電極群Gx1およびGx2のみが描かれている。前にも述べたように、入力用すだれ状電極Tx1に対応する電極群Gx1は出力用すだれ状電極Rxa1, Rxa2およびRxa3から成り、入力用すだれ状電極Tx2に対応する電極群Gx2は出力用すだれ状電極Rxb1, Rxb2およびRxb3から成る。入力用すだれ状電極Tx1, Tx2, Tx3, Tx4, Tx5, Ty1, Ty2, Ty3, Ty4およびTy5は同様な構造を有し、電極周期長は400μmである。電極群Gx1, Gx2, Gx3, Gx4, Gx5, Gy1, Gy2, Gy3, Gy4およびGy5は同様な構造を有し、電極周期長は400μmである。しかしながら、出力用すだれ状電極Rxa1, Rxa2およびRxa3と、出力用すだれ状電極Rxb1, Rxb2およびRxb3とでは、電極指の方向が互いに逆である。同様にして、出力用すだれ状電極Rya1, Rya2およびRya3と、出力用すだれ状電極Ryb1, Ryb2およびRyb3とでは、電極指の方向が互いに逆である。
【００２２】
図３はパネル部の断面図である。非圧電板１の厚さは1.5 mmである。液晶２は非圧電板１と非圧電板３の間に挟まれている。第１圧電基板８、第２圧電基板９、第３圧電基板１０および第４圧電基板１１の厚さは150μmである。
【００２３】
図４は超音波接触位置検出装置の一実施例を示す構成図である。非圧電板１、液晶２、非圧電板３、第１圧電基板８、第２圧電基板９、第３圧電基板１０および第４圧電基板１１は図４には描かれていない。端子Ux1, Ux2およびUx3は、出力用すだれ状電極Rxa1, Rxa2およびRxa3にそれぞれ接続されるとともに、出力用すだれ状電極Rxb1, Rxb2およびRxb3にそれぞれ接続されている。端子Uy1, Uy2およびUy3は、出力用すだれ状電極Rya1, Rya2およびRya3にそれぞれ接続されるとともに、出力用すだれ状電極Ryb1, Ryb2およびRyb3にそれぞれ接続されている。信号分析器４は端子Ux1, Ux2, Ux3, Uy1, Uy2およびUy3と接続されている。増幅器５は信号分析器４と、入力用すだれ状電極Tx1, Tx2, Tx3, Tx4, Tx5, Ty1, Ty2, Ty3, Ty4およびTy5との間に接続されている。
【００２４】
図４の超音波接触位置検出装置において、もしも第１入力電気信号が入力用すだれ状電極Tx1とTx2に第１スイッチ６を介して同時に印加されると、第１圧電基板８に第１弾性表面波が励振される。第１弾性表面波は、非圧電板１の上端面を伝わって、非圧電板１の内部に漏洩されることなく第２圧電基板９に伝搬される。第２圧電基板９に伝搬された第１弾性表面波は、電極群Gx1に含まれる出力用すだれ状電極Rxa1, Rxa2およびRxa3と、電極群Gx2に含まれる出力用すだれ状電極Rxb1, Rxb2およびRxb3のそれぞれにおいて第１出力電気信号に変換される。このとき、電極群Gx1の出力用すだれ状電極Rxa1, Rxa2およびRxa3での第１出力電気信号と、電極群Gx2の出力用すだれ状電極Rxb1, Rxb2およびRxb3での第１出力電気信号は、互いに位相が逆転している。従って、端子Ux1, Ux2およびUx3に電気信号が現れることはない。一般的には、第１入力電気信号が入力用すだれ状電極Tx1, Tx2, Tx3, Tx4およびTx5の隣り合う２つに同時に印加されると、第１圧電基板８に第１弾性表面波が励振される。第１弾性表面波は、非圧電板１の上端面を伝わって第２圧電基板９に伝搬され、電極群Gx1, Gx2, Gx3, Gx4およびGx5の隣り合う２つに含まれる出力用すだれ状電極Rxa1, Rxa2, Rxa3, Rxb1, Rxb2およびRxb3で第１出力電気信号に変換される。このようにして、入力用すだれ状電極Tx1, Tx2, Tx3, Tx4およびTx5と、電極群Gx1, Gx2, Gx3, Gx4およびGx5の間に全部で１５個の第１弾性表面波伝搬路が形成される。
【００２５】
もしも第２入力電気信号が入力用すだれ状電極Ty1, Ty2, Ty3, Ty4およびTy5の隣り合う２つに同時に印加されると、第３圧電基板１０に第２弾性表面波が励振される。第２弾性表面波は、非圧電板１の上端面を伝わって第４圧電基板１１に伝搬され、電極群Gy1, Gy2, Gy3, Gy4およびGy5の隣り合う２つに含まれる出力用すだれ状電極Rya1, Rya2, Rya3, Ryb1, Ryb2およびRyb3で第２出力電気信号に変換される。このようにして、入力用すだれ状電極Ty1, Ty2, Ty3, Ty4およびTy5と、電極群Gy1, Gy2, Gy3, Gy4およびGy5の間に全部で１５個の第２弾性表面波伝搬路が形成される。
【００２６】
図４の超音波接触位置検出装置では、もしも非圧電板１の上端面のどこにも接触しなければ、端子Ux1, Ux2, Ux3, Uy1, Uy2およびUy3のどこにも遅延電気信号は現れない。しかしながら、非圧電板１の上端面のどこかに接触することにより、端子Ux1, Ux2およびUx3のうちの１つに連続して２回の第１遅延電気信号が現われ、端子Uy1, Uy2およびUy3のうちの１つに連続して２回の第２遅延電気信号が現れる。これらの第１および第２遅延電気信号は信号分析器４で検出される。たとえば、入力用すだれ状電極Tx3と電極群Gx3の出力用すだれ状電極Rxa1との間の第１弾性表面波伝搬路と、入力用すだれ状電極Ty4と電極群Gy4の出力用すだれ状電極Ryb2との間の第２弾性表面波伝搬路の交点を接触すると、第１入力電気信号が入力用すだれ状電極Tx2およびTx3と、Tx3およびTx4とに連続して印加された場合に限って端子Ux1に第１遅延電気信号が連続して２回現われ、第２入力電気信号が入力用すだれ状電極Ty3およびTy4と、Ty4およびTy5とに連続して印加された場合に限って端子Uy2に第２遅延電気信号が連続して２回現れる。この場合、端子Ux1に連続して２回現れる第１遅延電気信号は、電極群Gx2の出力用すだれ状電極Rxb1での第１出力電気信号および電極群Gx4の出力用すだれ状電極Rxb1での第１出力電気信号に対応するものである。また、端子Uy2に連続して２回現れる第２遅延電気信号は、電極群Gy3の出力用すだれ状電極Rya2での第２出力電気信号および電極群Gy5の出力用すだれ状電極Rya2での第２出力電気信号に対応するものである。なぜならば、入力用すだれ状電極Tx3と電極群Gx3の出力用すだれ状電極Rxa1との間の第１弾性表面波と、入力用すだれ状電極Ty4と電極群Gy4の出力用すだれ状電極Ryb2との間の第２弾性表面波は、これら第１および第２弾性表面波にそれぞれ対応する第１および第２弾性表面波伝搬路の交点を接触することにより消失してしまうからである。つまり、第１入力電気信号が入力用すだれ状電極Tx3に連続して２回印加されたときに第１遅延電気信号が端子Ux1に連続して２回現れ、第２入力電気信号が入力用すだれ状電極Ty4に連続して２回印加されたときに第２遅延電気信号が端子Uy2に連続して２回現れる。このようにして、端子Ux1, Ux2およびUx3のうちの１つに第１遅延電気信号が連続して２回現われたときに第１入力電気信号が連続して２回印加されていたのは入力用すだれ状電極Tx1, Tx2, Tx3, Tx4およびTx5のうちのどれであるか、また、端子Uy1, Uy2およびUy3のうちの１つに第２遅延電気信号が連続して２回現れたときに第２入力電気信号が連続して２回印加されていたのは入力用すだれ状電極Ty1, Ty2, Ty3, Ty4およびTy5のうちのどれであるかを検出することにより、非圧電板１の上端面における接触位置を判別することが可能になる。
【００２７】
第１および第２遅延電気信号は、増幅器５を介してそれぞれ第１スイッチ６および第２スイッチ７に到達する。このようにして、自励振発振型の超音波タッチパネルを形成することが可能になり、従って、回路構成が簡単になり、低電圧で低消費電力駆動が可能となる。
【００２８】
図５は電気機械結合係数k²とfd値との関係を示す特性図である。但し、fd値は第１弾性表面波の周波数fと第１圧電基板８の厚さdとの積を示し、k²値は第１圧電基板８の異なる２つの電気的境界条件下、すなわち電気的開放および短絡状態での位相速度差から算出される。また、非圧電板１を伝搬する横波の速度は4,203 m/s、縦波の速度は7,604 m/sである。第１圧電基板８を伝搬する横波および縦波の速度はそれぞれ2,450 m/sおよび4,390 m/sであることから、非圧電板１における横波および縦波の速度は、第１圧電基板８におけるそれらの速度のほぼ1.7倍であることがわかる。図５より、fd値が0.7 MHzmmのときに１次モードのk²値が最大値の14 %を示すことが分かる。すなわち、１次モードの弾性表面波が最も効率よく第１圧電基板８に励振され、そのときのfd値は0.7 MHzmmであることが分かる。
【００２９】
図６は非圧電板１と第１圧電基板８との層状構造体を伝搬する弾性表面波の速度分散曲線を示す特性図である。各モードのk²値の最大値は図５から得られたもので、図６においては●印で示されている。各々の●印での位相速度はほぼ3,800 m/sであり、この値は非圧電板１自身を伝搬するレイリー波の位相速度3,860 m/sとほぼ等しいことが分かる。
【００３０】
図７は、非圧電板１と第１圧電基板８との層状構造体を伝搬する１次モードの弾性表面波の変位分布を示す特性図である。層状構造体の深さはd値で規格化されており、変位は最大値を１として規格化されている。弾性表面波の垂直成分は実線で、水平成分は破線で示されている。図７より、垂直成分も水平成分も非圧電板１と第１圧電基板８との境界付近に存在することが分かる。すなわち、両成分とも非圧電板１の深部には漏洩されないことが分かる。従って、図３のような、液晶２が非圧電板１と非圧電板３の間に挟まれたようなサンドイッチ構造が可能となる。
【００３１】
【発明の効果】
本発明の超音波接触位置検出装置は非圧電板と、第１および第２超音波伝搬手段と、信号分析器から成り、小型軽量で、デバイス構成が簡単で、回路構成も簡単である。従って、大量生産が可能である。また、非圧電板としてガラス板などが可能なことから、耐久性にも優れ、使用頻度の多さや煩雑な使用にも対応しうる。
【００３２】
本発明の超音波接触位置検出装置では、非圧電板の上端面を接触することにより、端子Uxjの１つに第１遅延電気信号が連続して２回現われ、端子Uyjの１つに第２遅延電気信号が連続して２回現れ、これらの第１および第２遅延電気信号は信号分析器で検出される。すなわち、端子Uxjの１つに第１遅延電気信号が連続して２回現われたときに第１入力電気信号が連続して２回印加されたのは入力用すだれ状電極Txiのうちのどれであるか、また、端子Uyjの１つに第２遅延電気信号が連続して２回現れたときに第２入力電気信号が連続して２回印加されたのは入力用すだれ状電極Tyiのうちのどれであるかを検出することにより、非圧電板の上端面における接触位置を判別することが可能になる。
【００３３】
本発明の超音波接触位置検出装置では、第１、第２、第３および第４圧電基板が一体化されて１つの窓枠構造となることが可能である。このような構造を採用することにより、製造工程を簡略化することができる。
【００３４】
本発明の超音波接触位置検出装置では、非圧電板の下端面にもう一つの非圧電板が備えられ、これら２つの非圧電板の間に液晶が満たされた構造が可能である。このような構造は、液晶のディスプレイとしての機能と一体化させることを可能にする。
【００３５】
本発明の超音波接触位置検出装置では、入力用すだれ状電極TxiおよびTyiにそれぞれ接続する第１および第２スイッチが備えられた構造が可能である。信号分析器で検出された第１および第２遅延電気信号は、増幅器を介して第１および第２スイッチにそれぞれ到達する。このようにして、自励振発振型の超音波タッチパネルを形成することが可能になる。従って、回路構成が簡単になり、低電圧で低消費電力駆動が可能となる。
【図面の簡単な説明】
【図１】本発明の超音波接触位置検出装置に含まれるパネル部の一実施例を示す平面図。
【図２】パネル部の部分拡大平面図。
【図３】パネル部の断面図。
【図４】超音波接触位置検出装置の一実施例を示す構成図。
【図５】電気機械結合係数k²とfd値との関係を示す特性図。
【図６】非圧電板１と第１圧電基板８との層状構造体を伝搬する弾性表面波の速度分散曲線を示す特性図。
【図７】非圧電板１と第１圧電基板８との層状構造体を伝搬する１次モードの弾性表面波の変位分布を示す特性図。
【符号の説明】
１非圧電板
２液晶
３非圧電板
４信号分析器
５増幅器
６第１スイッチ
７第２スイッチ
８第１圧電基板
９第２圧電基板
１０第３圧電基板
１１第４圧電基板
Tx1, Tx2, Tx3, Tx4, Tx5 入力用すだれ状電極
Gx1, Gx2, Gx3, Gx4, Gx5 電極群
Ux1, Ux2, Ux3 端子
Rxa1, Rxa2, Rxa3, Rxb1, Rxb2, Rxb3 出力用すだれ状電極
Ty1, Ty2, Ty3, Ty4, Ty5 入力用すだれ状電極
Gy1, Gy2, Gy3, Gy4, Gy5 電極群
Uy1, Uy2, Uy3 端子
Rya1, Rya2, Rya3, Ryb1, Ryb2, Ryb3 出力用すだれ状電極[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic contact position detecting device that determines a contact position when contacting a non-piezoelectric plate through which a surface acoustic wave is propagated.
[0002]
[Prior art]
Conventional touch panels generally include a wedge type transducer and a piezoelectric thin film transducer. The wedge-shaped transducer has a function of indirectly causing elastic vibration in the non-piezoelectric plate, and the piezoelectric thin film transducer has a function of causing elastic vibration directly in the non-piezoelectric plate. In any case, such a conventional touch panel utilizes the fact that the ultrasonic wave on the non-piezoelectric plate disappears due to contact with the non-piezoelectric plate, and the output electric signal is not detected. The contact position is determined from the arrangement of the output transducer that is no longer detected. Therefore, the conventional touch panel needs to drive all the input transducers at all times. Therefore, the conventional touch panel not only has a problem in driving voltage and power consumption but also requires a complicated circuit configuration. Furthermore, it has been difficult for conventional touch panels to excite ultrasonic waves directly on a non-piezoelectric plate in contact with the liquid crystal.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide an ultrasonic contact position detection device that can determine a contact position with high sensitivity by detecting a delayed electrical signal that appears by contacting one end face of a non-piezoelectric plate.
Another object of the present invention is that self-excited oscillation drive with low voltage and low power consumption is possible, the circuit configuration is simple, the response speed to contact is high, mass production is possible, it is compact and lightweight, and has excellent durability. Another object of the present invention is to provide an ultrasonic contact position detecting device capable of bringing liquid crystal into contact with the other end face of a non-piezoelectric plate.
[0004]
[Means for Solving the Problems]
The ultrasonic contact position detection device according to claim 1 is an ultrasonic contact position detection device including a non-piezoelectric plate, first and second ultrasonic wave propagation means, and a signal analyzer. The propagation means includes at least two interdigital electrodes Txi (i = 1, 2,..., M), at least two electrode groups Gxi (i = 1, 2,..., M), and first and second piezoelectric elements. A substrate and at least two terminals Uxj (j = 1, 2,..., N), and two adjacent ones of the electrode group Gxi are at least two output interdigital electrodes Rxaj (j = 1, 2,... n), and the other is composed of at least two output interdigital electrodes Rxbj (j = 1, 2,..., n), and the output interdigital electrodes Rxaj and Rxbj have opposite electrode finger directions. The terminal Uxj is connected to the output interdigital electrode Rxaj and is connected to the output interdigital electrode Rxbj, and the second The sound wave propagation means includes at least two interdigital electrodes Tyi (i = 1, 2,..., M), at least two electrode groups Gyi (i = 1, 2,..., M), and third and fourth electrodes. A piezoelectric substrate and at least two terminals Uyj (j = 1, 2,..., N), and two adjacent ones of the electrode group Gyi are at least two output interdigital electrodes Ryaj (j = 1, 2, ..., n), and the other consists of at least two output interdigital electrodes Rybj (j = 1, 2, ..., n), and the output interdigital electrodes Ryaj and Rybj The terminal Uyj is connected to the output interdigital electrode Ryaj and is connected to the output interdigital electrode Rybj, and the input interdigital electrode Txi, the electrode group Gxi, the input The interdigital electrode Tyi and the electrode group Gyi are provided on the first, second, third and fourth edges of the upper end surface of the non-piezoelectric plate, respectively. The first, second, third, and fourth piezoelectric substrates are provided on the input interdigital electrode Txi, the electrode group Gxi, the input interdigital electrode Tyi, and the electrode group Gyi, respectively. The analyzer is connected to the terminals Uxj and Uyj, and a first surface acoustic wave is excited on the first piezoelectric substrate by applying a first input electrical signal to two adjacent interdigital electrodes Txi. The first surface acoustic wave is propagated to the second piezoelectric substrate through the upper end surface of the non-piezoelectric plate, and is converted into a first output electric signal in each of the output interdigital electrodes Rxaj and Rxbj. By applying a second input electrical signal to two adjacent interdigital electrodes Tyi for input, a second surface acoustic wave is excited on the third piezoelectric substrate, and the second surface acoustic wave is The fourth piezoelectric element through the upper end surface of the non-piezoelectric plate Propagated to the substrate, converted into a second output electrical signal at each of the output interdigital electrodes Ryaj and Rybj, and brought into contact with the upper end surface of the non-piezoelectric plate, thereby causing a first delay to one of the terminals Uxj An electrical signal appears twice in succession, and a second delayed electrical signal appears twice in succession at one of the terminals Uyj, and the first and second delayed electrical signals are detected by the signal analyzer, When the first delayed electric signal appears twice in succession, it is detected which of the input interdigital electrodes Txi is applied with the first input electric signal twice in succession. In addition, when the second delayed electric signal appears twice in succession, which of the input interdigital electrodes Tyi is applied with the second input electric signal twice in succession. By detecting the non-piezoelectric plate Contact position on serial upper end face is determined.
[0005]
In the ultrasonic contact position detecting device according to claim 2, the first, second, third and fourth piezoelectric substrates are integrated to form one window frame structure.
[0006]
In the ultrasonic contact position detecting device according to claim 3, the first, second, third and fourth piezoelectric substrates are made of piezoelectric ceramic, and the direction of the polarization axis of the piezoelectric ceramic is parallel to the thickness direction thereof. is there.
[0007]
In the ultrasonic contact position detecting device according to a fourth aspect, the non-piezoelectric plate is made of a transparent material.
[0008]
The ultrasonic contact position detecting device according to claim 5, wherein the thickness of the first, second, third and fourth piezoelectric substrates is smaller than the electrode period length of the interdigital electrodes Txi and Tyi for input, The thickness of the non-piezoelectric plate is greater than three times the electrode period length.
[0009]
The ultrasonic contact position detecting device according to claim 6, wherein the surface velocity of the surface acoustic wave propagating to the non-piezoelectric plate itself propagates to the first, second, third and fourth piezoelectric substrates themselves. Faster than the phase velocity of.
[0010]
The ultrasonic contact position detection device according to claim 7, wherein another non-piezoelectric plate is provided on a lower end surface of the non-piezoelectric plate, and a liquid crystal is interposed between the non-piezoelectric plate and the other non-piezoelectric plate. be satisfied.
[0011]
In the ultrasonic contact position detecting apparatus according to the eighth aspect, an amplifier is provided between the signal analyzer and the input interdigital electrodes Txi and Tyi.
[0012]
The ultrasonic contact position detection apparatus according to claim 9 includes first and second switches connected to the input interdigital electrodes Txi and Tyi, respectively.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The ultrasonic contact position detection apparatus of the present invention has a simple structure including a non-piezoelectric plate, first and second ultrasonic wave propagation means, a signal analyzer, and an amplifier. The first ultrasonic wave propagation means includes at least two interdigital electrodes Txi (i = 1, 2,..., M), at least two electrode groups Gxi (i = 1, 2,..., M), and a first And a second piezoelectric substrate and at least two terminals Uxj (j = 1, 2,..., N). Two adjacent ones of the electrode group Gxi are composed of at least two output interdigital electrodes Rxaj (j = 1, 2,..., N), and the other is at least two output interdigital electrodes Rxbj (j = 1, 2, ..., n). The interdigital electrodes Rxaj and Rxbj for output have opposite electrode finger directions. The terminal Uxj is connected to the output interdigital electrode Rxaj and to the output interdigital electrode Rxbj. The second ultrasonic wave propagation means includes at least two interdigital electrodes Tyi (i = 1, 2,..., M), at least two electrode groups Gyi (i = 1, 2,..., M), and a third And a fourth piezoelectric substrate and at least two terminals Uyj (j = 1, 2,..., N). Two adjacent ones of the electrode group Gyi are composed of at least two output interdigital electrodes Ryaj (j = 1, 2,..., N), and the other is at least two output interdigital electrodes Rybj (j = 1, 2, ..., n). The output interdigital electrodes Ryaj and Rybj have opposite electrode finger directions. The terminal Uyj is connected to the output interdigital electrode Ryaj and to the output interdigital electrode Rybj. The input interdigital electrode Txi, the electrode group Gxi, the input interdigital electrode Tyi, and the electrode group Gyi are provided on the first, second, third, and fourth edges of the upper end surface of the non-piezoelectric plate, respectively. The first, second, third, and fourth piezoelectric substrates are provided on the input interdigital electrode Txi, the electrode group Gxi, the input interdigital electrode Tyi, and the electrode group Gyi, respectively. The signal analyzer is connected to terminals Uxj and Uyj.
[0014]
In the ultrasonic contact position detection apparatus of the present invention, if the first input electrical signal is applied simultaneously to two adjacent interdigital electrodes Txi, the first surface acoustic wave is excited on the first piezoelectric substrate. . At this time, since the first piezoelectric substrate is made of piezoelectric ceramic and the direction of the polarization axis of the piezoelectric ceramic is parallel to the thickness direction, the first surface acoustic wave is efficiently excited on the first piezoelectric substrate. . Furthermore, if the phase velocity of the first surface acoustic wave is substantially equal to the phase velocity of the Rayleigh wave of the surface acoustic wave propagating through the non-piezoelectric plate itself, the first input electrical signal is converted to the first surface acoustic wave with high efficiency. Converted. The first surface acoustic wave propagates through the upper end surface of the non-piezoelectric plate and propagates to the second piezoelectric substrate without leaking into the non-piezoelectric plate. The first surface acoustic wave is not leaked into the non-piezoelectric plate. First, the thickness of the first piezoelectric substrate is smaller than the electrode period length of the interdigital transducer Txi, and second, non-piezoelectric The thickness of the plate is greater than three times the electrode period length of the interdigital transducer Txi, and third, the phase velocity of the first surface acoustic wave propagating through the non-piezoelectric plate itself causes the first piezoelectric substrate itself to This is because the phase velocity of the propagating first surface acoustic wave is larger. The first surface acoustic wave propagated to the second piezoelectric substrate is converted into a first output electric signal in each of the output interdigital electrodes Rxaj and Rxbj. At this time, the phases of the first output electrical signal at the output interdigital electrode Rxaj and the first output electrical signal at the output interdigital electrode Rxbj are reversed. Therefore, an electric signal does not appear at all terminals Uxj. In this way, a total of (i × j) first surface acoustic wave propagation paths are formed between the interdigital transducer Txi and the electrode group Gxi. Similarly, if the second input electric signal is simultaneously applied to two adjacent interdigital electrodes Tyi, the second surface acoustic wave is excited on the third piezoelectric substrate. The second surface acoustic wave is propagated to the fourth piezoelectric substrate through the upper end surface of the non-piezoelectric plate, and is converted into a second output electric signal at each of the output interdigital electrodes Ryaj and Rybj. In this way, a total of (i × j) second surface acoustic wave propagation paths are formed between the interdigital transducer Tyi and the electrode group Gyi.
[0015]
If no contact is made anywhere on the top surface of the non-piezoelectric plate, no delayed electrical signal appears at any of the terminals Uxj and Uyj. However, by contacting somewhere on the upper end surface of the non-piezoelectric plate, the first delayed electrical signal appears twice in succession at one of the terminals Uxj, and the second delayed electrical signal continues at one of the terminals Uyj. Appears twice. In other words, when the first input electrical signal is applied twice in succession to one of the interdigital electrodes Txi, the first delayed electrical signal is applied twice in succession to one of the terminals Uxj. In addition, when the second input electrical signal is applied twice in succession to one of the interdigital electrodes Tyi for input, the second delayed electrical signal appears twice in succession at one of the terminals Uyj. In this way, when the first delayed electrical signal appears twice continuously at one of the terminals Uxj, the first input electrical signal was applied twice continuously because of the interdigital electrode Txi for input. And the second input electrical signal is applied twice in succession when the second delayed electrical signal appears twice in succession at one of the terminals Uyj. The contact position on the upper end surface of the non-piezoelectric plate can be determined by detecting which of the electrode electrodes Tyi is.
[0016]
In the ultrasonic contact position detection apparatus of the present invention, the first, second, third and fourth piezoelectric substrates can be integrated into a single window frame structure. By adopting such a structure, the manufacturing process can be simplified.
[0017]
In the ultrasonic contact position detection apparatus of the present invention, another non-piezoelectric plate is provided on the lower end surface of the non-piezoelectric plate, and a structure in which liquid crystal is filled between these two non-piezoelectric plates is possible. Such a structure makes it possible to integrate with the function as a liquid crystal display.
[0018]
In the ultrasonic contact position detecting apparatus of the present invention, a structure in which an amplifier is provided between the signal analyzer and the interdigital transducers Txi and Tyi is possible. By adopting such a structure, it is possible to form a self-excited oscillation type ultrasonic touch panel. Therefore, the circuit configuration is simplified, and low power consumption driving can be performed at a low voltage.
[0019]
In the ultrasonic contact position detecting device of the present invention, a structure including first and second switches connected to the interdigital electrodes Txi and Tyi for input is possible. By adopting such a structure, the circuit configuration can be simplified.
[0020]
【Example】
FIG. 1 is a plan view showing an embodiment of a panel unit included in the ultrasonic contact position detecting apparatus of the present invention. The ultrasonic contact position detecting device includes first and second ultrasonic wave propagation means, a non-piezoelectric plate 1, a liquid crystal 2, another non-piezoelectric plate 3, a signal analyzer 4, an amplifier 5, a first switch 6 and a second switch 7. Consists of. The first ultrasonic wave propagation means is the first piezoelectric substrate 8, the second piezoelectric substrate 9, the interdigital electrodes Tx1, Tx2, Tx3, Tx4 and Tx5, the electrode groups Gx1, Gx2, Gx3, Gx4 and Gx5, and the terminal Ux1, Consists of Ux2 and Ux3. Each of the electrode groups Gx1, Gx3 and Gx5 is composed of output interdigital electrodes Rxa1, Rxa2 and Rxa3. Each of the electrode groups Gx2 and Gx4 includes output interdigital electrodes Rxb1, Rxb2, and Rxb3. The second ultrasonic wave propagation means is the third piezoelectric substrate 10, the fourth piezoelectric substrate 11, the interdigital electrodes Ty1, Ty2, Ty3, Ty4 and Ty5, the electrode groups Gy1, Gy2, Gy3, Gy4 and Gy5, and the terminal Uy1, Consists of Uy2 and Uy3. Each of the electrode groups Gy1, Gy3, and Gy5 is composed of output interdigital electrodes Rya1, Rya2, and Rya3. Each of the electrode groups Gy2 and Gy4 is composed of output interdigital electrodes Ryb1, Ryb2, and Ryb3. Interdigital electrodes Tx1, Tx2, Tx3, Tx4 and Tx5, electrode group Gx1, Gx2, Gx3, Gx4 and Gx5, input interdigital electrodes Ty1, Ty2, Ty3, Ty4 and Ty5, electrode groups Gy1, Gy2, Gy3, Gy4 and Gy5 are provided on the first, second, third and fourth edge portions of the upper end surface of the non-piezoelectric plate 1, respectively. The first piezoelectric substrate 8 is provided on the input interdigital electrodes Tx1, Tx2, Tx3, Tx4 and Tx5, and the second piezoelectric substrate 9 is provided on the electrode group Gx1, Gx2, Gx3, Gx4 and Gx5. The third piezoelectric substrate 10 is provided on the input interdigital electrodes Ty1, Ty2, Ty3, Ty4, and Ty5, and the fourth piezoelectric substrate 11 is provided on the electrode groups Gy1, Gy2, Gy3, Gy4, and Gy5. At this time, instead of the first piezoelectric substrate 8, the second piezoelectric substrate 9, the third piezoelectric substrate 10, and the fourth piezoelectric substrate 11, one window frame structure type piezoelectric substrate formed by integrating them Can be used. Non-piezoelectric plate 1, liquid crystal 2, non-piezoelectric plate 3, first piezoelectric substrate 8, second piezoelectric substrate 9, third piezoelectric substrate 10, fourth piezoelectric substrate 11, interdigital electrodes Tx1, Tx2, Tx3, Tx4, Tx5, Ty1, Ty2, Ty3, Ty4 and Ty5, and electrode groups Gx1, Gx2, Gx3, Gx4, Gx5, Gy1, Gy2, Gy3, Gy4 and Gy5 form a panel portion. In FIG. 1, the first piezoelectric substrate 8, the second piezoelectric substrate 9, the third piezoelectric substrate 10, and the fourth piezoelectric substrate 11 are not drawn. The non-piezoelectric plate 1 is made of a transparent glass plate, and the phase velocity of the surface acoustic wave propagating through the non-piezoelectric plate 1 itself is faster than the phase velocity of the surface acoustic wave propagating through the first piezoelectric substrate 8 itself. Interdigital transducers Tx1, Tx2, Tx3, Tx4, Tx5, Ty1, Ty2, Ty3, Ty4 and Ty5, electrode groups Gx1, Gx2, Gx3, Gx4, Gx5, Gy1, Gy2, Gy3, Gy4 and Gy5 are each aluminum It consists of a thin film. The first piezoelectric substrate 8, the second piezoelectric substrate 9, the third piezoelectric substrate 10, and the fourth piezoelectric substrate 11 are made of piezoelectric ceramic, and the direction of the polarization axis of the piezoelectric ceramic is parallel to the thickness direction.
[0021]
FIG. 2 is a partially enlarged plan view of the panel portion. In FIG. 2, only the electrode groups Gx1 and Gx2 provided on the non-piezoelectric plate 1 are illustrated. As described above, the electrode group Gx1 corresponding to the input interdigital electrode Tx1 is composed of the output interdigital electrodes Rxa1, Rxa2 and Rxa3, and the electrode group Gx2 corresponding to the input interdigital electrode Tx2 is the output interdigital transducer. It consists of electrode electrodes Rxb1, Rxb2 and Rxb3. The interdigital electrodes Tx1, Tx2, Tx3, Tx4, Tx5, Ty1, Ty2, Ty3, Ty4 and Ty5 have the same structure and the electrode cycle length is 400 μm. The electrode groups Gx1, Gx2, Gx3, Gx4, Gx5, Gy1, Gy2, Gy3, Gy4 and Gy5 have the same structure, and the electrode cycle length is 400 μm. However, the output interdigital electrodes Rxa1, Rxa2, and Rxa3 and the output interdigital electrodes Rxb1, Rxb2, and Rxb3 have opposite electrode finger directions. Similarly, the output interdigital electrodes Rya1, Rya2, and Rya3 and the output interdigital electrodes Ryb1, Ryb2, and Ryb3 have opposite electrode finger directions.
[0022]
FIG. 3 is a cross-sectional view of the panel portion. The thickness of the non-piezoelectric plate 1 is 1.5 mm. The liquid crystal 2 is sandwiched between the non-piezoelectric plate 1 and the non-piezoelectric plate 3. The thickness of the first piezoelectric substrate 8, the second piezoelectric substrate 9, the third piezoelectric substrate 10 and the fourth piezoelectric substrate 11 is 150 μm.
[0023]
FIG. 4 is a block diagram showing an embodiment of the ultrasonic contact position detecting device. The non-piezoelectric plate 1, the liquid crystal 2, the non-piezoelectric plate 3, the first piezoelectric substrate 8, the second piezoelectric substrate 9, the third piezoelectric substrate 10, and the fourth piezoelectric substrate 11 are not drawn in FIG. The terminals Ux1, Ux2 and Ux3 are connected to the output interdigital electrodes Rxa1, Rxa2 and Rxa3, respectively, and are connected to the output interdigital electrodes Rxb1, Rxb2 and Rxb3, respectively. The terminals Uy1, Uy2 and Uy3 are connected to the output interdigital electrodes Rya1, Rya2 and Rya3, respectively, and are connected to the output interdigital electrodes Ryb1, Ryb2 and Ryb3, respectively. The signal analyzer 4 is connected to terminals Ux1, Ux2, Ux3, Uy1, Uy2 and Uy3. The amplifier 5 is connected between the signal analyzer 4 and the interdigital electrodes Tx1, Tx2, Tx3, Tx4, Tx5, Ty1, Ty2, Ty3, Ty4 and Ty5.
[0024]
In the ultrasonic contact position detection apparatus of FIG. 4, if the first input electrical signal is applied simultaneously to the interdigital electrodes Tx1 and Tx2 via the first switch 6, the first elastic surface is applied to the first piezoelectric substrate 8. Waves are excited. The first surface acoustic wave propagates through the upper end surface of the non-piezoelectric plate 1 and propagates to the second piezoelectric substrate 9 without leaking into the non-piezoelectric plate 1. The first surface acoustic waves propagated to the second piezoelectric substrate 9 are output interdigital electrodes Rxa1, Rxa2 and Rxa3 included in the electrode group Gx1, and output interdigital electrodes Rxb1, Rxb2 and Rxb3 included in the electrode group Gx2. Is converted into a first output electrical signal. At this time, the first output electric signal at the output interdigital electrodes Rxa1, Rxa2 and Rxa3 of the electrode group Gx1 and the first output electric signal at the output interdigital electrodes Rxb1, Rxb2 and Rxb3 of the electrode group Gx2 are mutually The phase is reversed. Therefore, no electrical signal appears at the terminals Ux1, Ux2, and Ux3. In general, when a first input electrical signal is applied simultaneously to two adjacent interdigital electrodes Tx1, Tx2, Tx3, Tx4, and Tx5, a first surface acoustic wave is excited on the first piezoelectric substrate 8. Is done. The first surface acoustic wave propagates along the upper end surface of the non-piezoelectric plate 1 to the second piezoelectric substrate 9, and is an output interdigital electrode included in two adjacent electrode groups Gx1, Gx2, Gx3, Gx4 and Gx5. Rxa1, Rxa2, Rxa3, Rxb1, Rxb2, and Rxb3 are converted into first output electric signals. In this manner, a total of 15 first surface acoustic wave propagation paths are formed between the interdigital electrodes Tx1, Tx2, Tx3, Tx4 and Tx5 and the electrode groups Gx1, Gx2, Gx3, Gx4 and Gx5. The
[0025]
If the second input electrical signal is simultaneously applied to two adjacent interdigital electrodes Ty1, Ty2, Ty3, Ty4, and Ty5, the second surface acoustic wave is excited on the third piezoelectric substrate 10. The second surface acoustic wave propagates along the upper end surface of the non-piezoelectric plate 1 to the fourth piezoelectric substrate 11, and is an output interdigital electrode included in two adjacent electrode groups Gy1, Gy2, Gy3, Gy4, and Gy5. Rya1, Rya2, Rya3, Ryb1, Ryb2 and Ryb3 are converted into second output electric signals. In this way, a total of 15 second surface acoustic wave propagation paths are formed between the interdigital electrodes Ty1, Ty2, Ty3, Ty4 and Ty5 and the electrode groups Gy1, Gy2, Gy3, Gy4 and Gy5. The
[0026]
In the ultrasonic contact position detection device of FIG. 4, if no contact is made anywhere on the upper end surface of the non-piezoelectric plate 1, no delayed electrical signal appears at any of the terminals Ux1, Ux2, Ux3, Uy1, Uy2 and Uy3. However, by contacting somewhere on the upper end surface of the non-piezoelectric plate 1, two first delayed electrical signals appear in succession at one of the terminals Ux1, Ux2 and Ux3, and the terminals Uy1, Uy2 and Uy3 Two second delayed electrical signals appear in succession on one of them. These first and second delayed electrical signals are detected by the signal analyzer 4. For example, the first surface acoustic wave propagation path between the input interdigital electrode Tx3 and the output interdigital electrode Rxa1 of the electrode group Gx3, the input interdigital electrode Ty4 and the output interdigital electrode Ryb2 of the electrode group Gy4, When the intersection of the second surface acoustic wave propagation path is contacted, the first input electric signal is applied to the terminal Ux1 only when the interdigital electrodes Tx2 and Tx3 for input and Tx3 and Tx4 are continuously applied. The second delay is applied to the terminal Uy2 only when the first delayed electric signal appears twice in succession and the second input electric signal is continuously applied to the interdigital electrodes Ty3 and Ty4 and Ty4 and Ty5. The electrical signal appears twice in succession. In this case, the first delayed electric signal that appears twice at the terminal Ux1 continuously is the first output electric signal at the output interdigital electrode Rxb1 of the electrode group Gx2 and the first output electric signal at the output interdigital electrode Rxb1 of the electrode group Gx4. It corresponds to one output electrical signal. The second delayed electrical signal that appears twice at the terminal Uy2 is the second output electrical signal at the output interdigital electrode Rya2 of the electrode group Gy3 and the second output electrical signal at the output interdigital electrode Rya2 of the electrode group Gy5. It corresponds to the output electrical signal. This is because the first surface acoustic wave between the input interdigital electrode Tx3 and the output interdigital electrode Rxa1 of the electrode group Gx3, and the input interdigital electrode Ty4 and the output interdigital electrode Ryb2 of the electrode group Gy4. This is because the second surface acoustic wave in the meantime disappears by contacting the intersections of the first and second surface acoustic wave propagation paths corresponding to the first and second surface acoustic waves, respectively. That is, when the first input electric signal is applied twice to the interdigital transducer Tx3 continuously, the first delayed electric signal appears twice at the terminal Ux1, and the second input electric signal is the input interdigital transducer. When applied to the electrode Ty4 twice in succession, the second delayed electric signal appears twice at the terminal Uy2. Thus, when the first delayed electrical signal appears twice in succession at one of the terminals Ux1, Ux2 and Ux3, the first input electrical signal is applied twice in succession. Interdigital electrodes Tx1, Tx2, Tx3, Tx4 and Tx5, and when the second delayed electrical signal appears twice in succession at one of the terminals Uy1, Uy2 and Uy3 By detecting which of the interdigital electrodes Ty1, Ty2, Ty3, Ty4 and Ty5 the second input electric signal was applied twice in succession on the non-piezoelectric plate 1 It is possible to determine the contact position on the end face.
[0027]
The first and second delayed electrical signals reach the first switch 6 and the second switch 7 through the amplifier 5, respectively. In this way, a self-excited oscillation type ultrasonic touch panel can be formed. Therefore, the circuit configuration is simplified and low-power consumption driving can be performed at a low voltage.
[0028]
Figure 5 shows the electromechanical coupling coefficient k ² FIG. Here, the fd value represents the product of the frequency f of the first surface acoustic wave and the thickness d of the first piezoelectric substrate 8, and k ² The value is calculated from the phase velocity difference between the two different electrical boundary conditions of the first piezoelectric substrate 8, that is, in the electrically open and short-circuited state. The velocity of the transverse wave propagating through the non-piezoelectric plate 1 is 4,203 m / s, and the velocity of the longitudinal wave is 7,604 m / s. Since the velocity of the transverse wave and the longitudinal wave propagating through the first piezoelectric substrate 8 is 2,450 m / s and 4,390 m / s, respectively, the velocity of the transverse wave and the longitudinal wave in the non-piezoelectric plate 1 is the same as that in the first piezoelectric substrate 8. It can be seen that the speed is almost 1.7 times. From Fig.5, k of primary mode when fd value is 0.7 MHzmm. ² It can be seen that the value represents 14% of the maximum value. That is, it can be seen that the surface acoustic wave of the first mode is most efficiently excited on the first piezoelectric substrate 8 and the fd value at that time is 0.7 MHz mm.
[0029]
FIG. 6 is a characteristic diagram showing velocity dispersion curves of surface acoustic waves propagating through the layered structure of the non-piezoelectric plate 1 and the first piezoelectric substrate 8. K for each mode ² The maximum value was obtained from FIG. 5, and is indicated by the mark ● in FIG. It can be seen that the phase velocity at each mark ● is approximately 3,800 m / s, and this value is substantially equal to the phase velocity 3,860 m / s of the Rayleigh wave propagating through the non-piezoelectric plate 1 itself.
[0030]
FIG. 7 is a characteristic diagram showing the displacement distribution of the surface acoustic wave in the first mode propagating through the layered structure of the non-piezoelectric plate 1 and the first piezoelectric substrate 8. The depth of the layered structure is normalized by the d value, and the displacement is normalized by setting the maximum value to 1. The vertical component of the surface acoustic wave is indicated by a solid line, and the horizontal component is indicated by a broken line. From FIG. 7, it can be seen that both vertical and horizontal components exist near the boundary between the non-piezoelectric plate 1 and the first piezoelectric substrate 8. That is, it can be seen that both components are not leaked into the deep part of the non-piezoelectric plate 1. Therefore, a sandwich structure in which the liquid crystal 2 is sandwiched between the non-piezoelectric plate 1 and the non-piezoelectric plate 3 as shown in FIG. 3 is possible.
[0031]
【The invention's effect】
The ultrasonic contact position detecting apparatus of the present invention comprises a non-piezoelectric plate, first and second ultrasonic wave propagation means, and a signal analyzer, is small and light, has a simple device configuration, and a simple circuit configuration. Therefore, mass production is possible. Further, since a glass plate or the like can be used as the non-piezoelectric plate, it is excellent in durability and can cope with frequent use and complicated use.
[0032]
In the ultrasonic contact position detection apparatus of the present invention, the first delayed electrical signal appears twice in succession at one of the terminals Uxj by contacting the upper end surface of the non-piezoelectric plate, and the second at one of the terminals Uyj. The delayed electrical signal appears twice in succession, and these first and second delayed electrical signals are detected by a signal analyzer. That is, when the first delayed electrical signal appears twice at one of the terminals Uxj, the first input electrical signal is applied twice continuously at any of the interdigital electrodes Txi for input. In addition, when the second delayed electric signal appears twice at one of the terminals Uyj, the second input electric signal is applied twice continuously among the interdigital electrodes Tyi for input. It is possible to determine the contact position on the upper end surface of the non-piezoelectric plate.
[0033]
In the ultrasonic contact position detection apparatus of the present invention, the first, second, third and fourth piezoelectric substrates can be integrated into a single window frame structure. By adopting such a structure, the manufacturing process can be simplified.
[0034]
In the ultrasonic contact position detection apparatus of the present invention, another non-piezoelectric plate is provided on the lower end surface of the non-piezoelectric plate, and a structure in which liquid crystal is filled between these two non-piezoelectric plates is possible. Such a structure makes it possible to integrate with the function as a liquid crystal display.
[0035]
In the ultrasonic contact position detecting device of the present invention, a structure including first and second switches connected to the interdigital electrodes Txi and Tyi for input is possible. The first and second delayed electrical signals detected by the signal analyzer reach the first and second switches through the amplifier, respectively. In this manner, a self-excited oscillation type ultrasonic touch panel can be formed. Therefore, the circuit configuration is simplified, and low power consumption driving can be performed at a low voltage.
[Brief description of the drawings]
FIG. 1 is a plan view showing an embodiment of a panel unit included in an ultrasonic contact position detection apparatus of the present invention.
FIG. 2 is a partially enlarged plan view of a panel unit.
FIG. 3 is a cross-sectional view of a panel portion.
FIG. 4 is a configuration diagram showing an embodiment of an ultrasonic contact position detection apparatus.
FIG. 5 Electromechanical coupling coefficient k ² And FIG. 5 is a characteristic diagram showing the relationship between fd values.
6 is a characteristic diagram showing a velocity dispersion curve of a surface acoustic wave propagating through a layered structure of a non-piezoelectric plate 1 and a first piezoelectric substrate 8. FIG.
7 is a characteristic diagram showing a displacement distribution of a surface acoustic wave of a first-order mode propagating through a layered structure of a non-piezoelectric plate 1 and a first piezoelectric substrate 8. FIG.
[Explanation of symbols]
1 Non-piezoelectric plate
2 Liquid crystal
3 Non-piezoelectric plate
4 signal analyzers
5 Amplifier
6 First switch
7 Second switch
8 First piezoelectric substrate
9 Second piezoelectric substrate
10 Third piezoelectric substrate
11 Fourth piezoelectric substrate
Tx1, Tx2, Tx3, Tx4, Tx5 Input interdigital electrodes
Gx1, Gx2, Gx3, Gx4, Gx5 Electrode group
Ux1, Ux2, Ux3 terminals
Rxa1, Rxa2, Rxa3, Rxb1, Rxb2, Rxb3 Output interdigital electrodes
Ty1, Ty2, Ty3, Ty4, Ty5 Interdigital electrodes for input
Gy1, Gy2, Gy3, Gy4, Gy5 Electrode group
Uy1, Uy2, Uy3 terminals
Rya1, Rya2, Rya3, Ryb1, Ryb2, Ryb3 Output interdigital electrodes

Claims

An ultrasonic contact position detecting device , comprising a non -piezoelectric plate, first and second ultrasonic wave propagation means, and a signal analyzer, for determining a contact position on an upper end surface of the non-piezoelectric plate , wherein the first ultrasonic wave The propagation means includes at least two interdigital electrodes Txi (i = 1, 2,..., M), at least two electrode groups Gxi (i = 1, 2,..., M), and first and second piezoelectric elements. A substrate and at least two terminals Uxj (j = 1, 2,..., N), and two adjacent ones of the electrode group Gxi are at least two output interdigital electrodes Rxaj (j = 1, 2,... n), and the other consists of at least two output interdigital electrodes Rxbj (j = 1, 2,..., n), and the direction of the electrode fingers of at least two of the output interdigital electrodes Rxaj is the same as each other And the direction of the electrode fingers of at least two of the output interdigital electrodes Rxbj is the same, and the output interdigital electrodes Rxaj The direction of the electrode finger and the direction of the electrode finger of the output interdigital electrode Rxbj are opposite to each other, and the terminal Uxj is connected to the output interdigital electrode Rxaj and the output interdigital electrode Each of the second ultrasonic wave propagation means is connected to Rxbj and includes at least two interdigital electrodes Tyi (i = 1, 2,..., M) and at least two electrode groups Gyi (i = 1, 2,. m), the third and fourth piezoelectric substrates, and at least two terminals Uyj (j = 1, 2,..., n), and one of the two adjacent electrodes of the electrode group Gyi is at least two output drains. Electrode Ryaj (j = 1, 2,..., N), the other is composed of at least two output interdigital electrodes Rybj (j = 1, 2,..., N), and at least two output interdigital transducers The directions of the electrode fingers of the electrode Ryaj are the same as each other, and the directions of the electrode fingers of at least two of the output interdigital electrodes Rybj Are identical to each other, the direction of the electrode fingers of the output interdigital transducer Ryaj, the direction of the electrode fingers of the output IDT Rybj are opposite to each other, the terminal Uyj are interdigital electrodes Ryaj for the output Connected to the output interdigital electrode Rybj, the input interdigital electrode Txi, the electrode group Gxi, the input interdigital electrode Tyi, and the electrode group Gyi are formed of the non-piezoelectric plate. The first, second, third, and fourth piezoelectric substrates are provided on the first, second, third, and fourth edges of the upper end surface , respectively, and the input interdigital electrode Txi, the electrode group Gxi Are provided on the input interdigital electrode Tyi and the electrode group Gyi, respectively, the signal analyzer is connected to the terminals Uxj and Uyj, and two adjacent interdigital electrodes Txi are first When an input electrical signal is applied The first surface acoustic wave excited in the first piezoelectric substrate, said first surface acoustic wave through the upper end surface of the non-piezoelectric plate has a function of propagating the second piezoelectric substrate, said first Two adjacent electrode groups Gxi corresponding to the propagation path of the surface acoustic wave have a function of converting the first surface acoustic wave into a first output electrical signal via the output interdigital electrodes Rxaj and Rxbj. The two adjacent interdigital electrodes Tyi input the second surface acoustic wave to the third piezoelectric substrate by applying a second input electrical signal, and the second surface acoustic wave is applied to the second surface acoustic wave. The two adjacent electrode groups Gyi corresponding to the propagation path of the second surface acoustic wave have a function of propagating to the fourth piezoelectric substrate through the upper end surface of the non-piezoelectric plate, and the output interdigital transducer convert the second surface acoustic wave to the second output electric signals through the electrode Ryaj and Rybj The first output electrical signal and the second output electrical signal have their phases reversed, and one of the terminals Uxj and one of the terminals Uyj is formed by the upper end surface of the non-piezoelectric plate. The contact analyzer has a function of outputting the first delayed electrical signal and the second delayed electrical signal twice in succession, and the signal analyzer detects the first and second delayed electrical signals, When the first delayed electrical signal is output twice in succession at one of the terminals Uxj, the first input electrical signal is applied twice in succession to the input interdigital electrode Txi. And the second input electrical signal was applied twice in succession when the second delayed electrical signal was output twice in succession at one of the terminals Uyj . Detects which of the input interdigital electrodes Tyi is It makes ultrasonic contact position detecting apparatus characterized by having a function of determining a contact position on the upper surface of the non-piezoelectric plate.

The ultrasonic contact position detection apparatus according to claim 1, wherein the first, second, third, and fourth piezoelectric substrates are integrated to form a single window frame structure.

The ultrasonic contact position detection according to claim 1 or 2, wherein the first, second, third and fourth piezoelectric substrates are made of piezoelectric ceramic, and a direction of a polarization axis of the piezoelectric ceramic is parallel to a thickness direction thereof. apparatus.

The ultrasonic contact position detecting device according to claim 1, wherein the non-piezoelectric plate is made of a transparent material.

The thicknesses of the first, second, third and fourth piezoelectric substrates are smaller than the electrode period length of the interdigital transducers Txi and Tyi, and the thickness of the non-piezoelectric plate is three times the electrode period length. The ultrasonic contact position detecting device according to claim 1, 2, 3, or 4, which is larger than that.

The phase velocity of surface acoustic waves propagating to the non-piezoelectric plate itself is faster than the phase velocity of surface acoustic waves propagating to the first, second, third and fourth piezoelectric substrates themselves. The ultrasonic contact position detection apparatus according to 4 or 5.

The other non-piezoelectric plate is provided at the lower end surface of the non-piezoelectric plate, and liquid crystal is filled between the non-piezoelectric plate and the other non-piezoelectric plate. The ultrasonic contact position detection apparatus according to 5 or 6.

8. The ultrasonic contact position detecting device according to claim 1, wherein an amplifier is provided between the signal analyzer and the interdigital electrodes Txi and Tyi for input.

9. The ultrasonic contact position detecting device according to claim 1, further comprising first and second switches connected to the interdigital electrodes Txi and Tyi for input, respectively.