JP3920119B2 - Ultrasonic transducer and apparatus, and fish finder - Google Patents

Description

なお、表１及び図２２中、ＢＭ０は各振動子アレイにおける同相励振又は同相合成により形成されるビームであり、Ｚ軸方向を向いている。ＢＭＡ１及びＢＭＡ２は振動子アレイＡにおける逆相励振又は逆相合成により形成されるビームであり、ＸＺ平面に属している。ＢＭＢ１及びＢＭＢ２は振動子アレイＢにおける逆相励振又は逆相合成により形成されるビームであり、ＸＺ平面に対してＺ軸回りに−２π／３（ｒａｄ）回転した平面に属している。ＢＭＣ１及びＢＭＣ２は振動子アレイＣにおける逆相励振又は逆相合成により形成されるビームであり、ＸＺ平面に対してＺ軸回りに２π／３（ｒａｄ）回転した平面に属している。Ｚ軸は船底直下方向（図１中の開口形成面即ち輻射面に鉛直な方向）を向いており、Ｘ軸及びＹ軸は輻射面に属している。Ｘ軸は、例えば、船首方向とする。
【００１２】
以上のように、先提案技術によれば、７方向（準）同時探知を行うことができる。また、正三角形格子パターン１８に従い振動子１２を配置しているためビーム間隔が均一であり、従って船舶下の水中をくまなく網羅して観測できる。振動子密度が比較的高いため、３個の振動子アレイを含んでいるにもかかわらず、遮音体１０に組み込んだ状態での超音波送受波器全体の寸法が、１個しか振動子アレイを備えていないものとさほど変わらない。即ち、低コスト及び省スペースである。また、繰り返し配列の結果、励振用配線が一組（２種類）ですんでいる。即ち、各振動子アレイに対応した励振用配線を設ける必要がなく、３個の振動子アレイＡ〜Ｃを低コストで形成できる。
【００１３】
図２４に、先提案技術による魚群探知機の全体の回路・機能構成を示す。ＣＰＵ等にて構成される制御回路２６は、駆動信号発生回路２８及び３０に対し基準発振信号及びその分周比を設定する信号を供給し、駆動信号発生回路２８及び３０内部における基準発振信号の分周動作を制御し、更に分周により得られた信号をパルス変調することによって、図２３に示したタイミングで駆動信号Ｓ１及びＳ２を発生させる。パワーアンプ３２及び３４は、これらの駆動信号Ｓ１及びＳ２のうち対応するものを電力増幅することによって前述の信号ＴＸ１及びＴＸ２を発生させ、超音波送受波器３６に供給する。超音波送受波器３６は図１３〜図１８に示した構成を有している。超音波送受波器３６はＸ軸を船首方向に向けＺ軸を深度方向（船底直下方向）に向けて船底に配設されており、信号ＴＸ１及びＴＸ２に応じて超音波を水中に輻射する。
【００１４】
水中の魚群等により反射された超音波は、超音波送受波器３６により受波され電気信号に変換される。得られた信号ＲＸＡ１〜ＲＸＡ４、ＲＸＢ１〜ＲＸＢ４及びＲＸＣ１〜ＲＸＣ４は、プリアンプ部３８により増幅され、信号ＲＸＳ１〜ＲＸＳ１２としてビーム合成回路４０に供給される。ビーム合成回路４０は、制御回路２６による制御の下に、これらの信号ＲＸＳ１〜ＲＸＳ１２からビームＢＭＡ１、ＢＭＡ２、ＢＭＢ１、ＢＭＢ２、ＢＭＣ１、ＢＭＣ２及びＢＭ０に係る信号を合成する。合成された信号は、各ビームに対応して７個設けられている受信処理回路４２に供給される。受信処理回路４２では、ビーム合成回路４０からの信号に関し、ＴＶＧ（時間可変利得）回路４４が超音波伝搬減衰による反射エコーレベルの低下分の補正処理を施し、検波回路４６が検波により直流信号に変換し、ＡＤ変換器４８がこの直流信号をアナログからディジタルに変換して制御回路２６に供給する。制御回路２６は、各受信処理回路４２から供給されるディジタル信号に基づき、表示器５０の画面上に各方向における魚群の有無、規模等の情報を表示させる。使用者は、表示器５０の画面表示を看取することにより、多方面についての魚群情報を得ることができる。特に、制御回路２６内部における映像合成処理により、図２２に示した複数のビームを利用して水中の状況に関する立体的な映像を提供することができる。
【００１５】
パワーアンプ３２及び３４やプリアンプ部３８と超音波送受波器３６との間に設けられている送受切換器５２は、駆動信号ＴＸ１及びＴＸ２が供給されているときには振動子１２の負電極１６を自動的に接地導体としてプリアンプ部３８以後の受信側回路を超音波送受波器３６から実質的に切り離し、そうでないときには振動子１２の正電極１４を自動的に接地導体としてパワーアンプ３２及び３４以前の送信側回路を超音波送受波器３６から実質的に切り離すための回路である。言い換えれば、駆動信号ＴＸ１及びＴＸ２が供給されているときには超音波送受波器３６を実質的に超音波送波器としてのみ使用し、そうでないときには超音波受波器としてのみ使用することができるようにするための回路である。
【００１６】
図２５に、送受切換器５２の一例構成を示す。この図の送受切換器５２は送信側の回路５４及び受信側の回路５６から構成されている。送信側の回路５４は、パワーアンプ３２及び３４各々とこれに対応する励振用配線２２との間に、それぞれ設けられている。この回路５４は、対応するパワーアンプと対応する励振用配線２２との間に接続されかつ互いに逆並列接続されているダイオードＤ１及びＤ２、これらのダイオードＤ１及びＤ２の超音波送受波器３６側の端に接続されているキャパシタＣ、このキャパシタＣと接地との間に接続されているインダクタＬ、並びにこのインダクタＬと並列にかつ互いに逆並列されているダイオードＤ３及びＤ４から構成されている。キャパシタＣ及びインダクタＬは信号ＴＸ１及びＴＸ２の搬送周波数即ち送信周波数ｆ０にて直列共振するようその値が設定されている。
【００１７】
他方、受信側の回路５６は、超音波送受波器３６の受波用配線２４各々とこれに対応するプリアンプ５８との間に、それぞれ設けられている。なお、前述のプリアンプ部３８はこの合計１２個のプリアンプ５８により構成されている。受信側の回路５６は、接地との間に接続され互いに逆並列接続されているダイオードＤ５及びＤ６から構成されている。
【００１８】
従って、パワーアンプ３２及び３４を介し駆動信号ＴＸ１及びＴＸ２（厳密にはその中の送信パルス）が供給されている期間（図２３中のＴ１＋Ｔ３＋Ｔ２）には、回路５４中のインダクタＬの両端間が短絡されると共に各受波用配線２４の一端が回路５６において接地される。また、それ以外の期間には、回路５４中のキャパシタＣ及びインダクタＬが受波信号中の送信周波数成分により共振するため各励振用配線２２が一端接地状態になる。
【００１９】
ビーム合成回路４０は、例えば、図２６に示す構成とすることができる。この図に示すビーム合成回路４０は、合成すべき合計７個のビームに対応して設けられている結合器６２それぞれに、局部発振回路６０の発振出力である移相制御信号と共に、信号ＲＸＳ１〜ＲＸＳ１２を入力する構成を有している。局部発振回路６０は、先に表１に示したように、合計７組の移相制御信号を発生させている。即ち、ビームＢＭＡ１に対応する結合器６２に対しては移相制御信号ＬＳ１−１〜ＬＳ１−１２を、ビームＢＭＡ２に対応する結合器６２に対しては移相制御信号ＬＳ２−１〜ＬＳ２−１２を、…そしてビームＢＭ０に対応する結合器６２に対しては移相制御信号ＬＳ７−１〜ＬＳ７−１２を、それぞれ供給する。各移相制御信号は、例えば、制御回路２６から供給される基準発振信号を、制御回路２６により設定される分周比にて分周し、更にこの分周のために用いるカウンタの初期値を適宜ずらして設定する（初期位相を与える）ことにより、発生させることができる。このようにして発生させた移相制御信号は、実現すべき移相量をその初期位相とする信号になる。
【００２０】
各結合器６２は、移相回路として動作する回路であり、例えば図２７に示す構成を有している。この図に示す結合器６２は、入力する信号ＲＸＳ１〜ＲＸＳ１２それぞれに対応して設けられたバッファ６４、このバッファ６４を介し供給される信号ＲＸＳ１〜ＲＸＳ１２各々とこれに対応する移相制御信号ＬＳｉ−１〜ＬＳｉ−１２（ｉ＝１，２，…７）とを乗算結合させる乗算器６６、各乗算器６６の出力を加算結合させる加算器６８、並びに加算器６８の出力信号に帯域制限を加え必要な周波数成分のみを取り出すＢＰＦ７０から構成されている。
【００２１】
各乗算器６６は、図２８に示すように、アナログスイッチ７２及びＢＰＦ７４から構成されている。スイッチ７２は、供給される移相制御信号ＬＳｉ−ｊ（ｊ＝１，２，…１２）に応じて信号ＲＸＳｊをスイッチングする手段である。例えば、送信周波数ｆ０が５０ｋＨｚであるときには、５０５ｋＨｚの周波数を有する信号を移相制御信号ＬＳｉ−ｊとして供給しスイッチングを行うことにより、移相制御信号ＬＳｉ−ｊに従い変調された信号が得られる。この信号には、和周波数即ち５０５ｋＨｚ＋５０ｋＨｚ＝５５５ｋＨｚの成分と、差周波数即ち５０５ｋＨｚ−５０ｋＨｚ＝４５５ｋＨｚの成分とが含まれており、その位相は、移相制御信号ＬＳｉ−ｊの初期位相により決定されている。ＢＰＦ７４は、この信号に含まれる周波数成分のうち差周波数の成分（上述の例では４５５ｋＨｚの成分）を通過させる。移相制御信号ＬＳｉ−ｊには、実現すべき移相量に相当する初期位相が付与されているから、当該移相量だけ移相された信号をＢＰＦ７４ひいては乗算器６６から得ることができる。
【００２２】
【発明が解決しようとする課題】
以上のように、先提案技術によれば、所定の振動子配列規則に従い配列した振動子並びに所定の結線規則に従い振動子間を結線する励振用及び受波用配線により、繰り返しの単位となる単位配列を形成し、この単位配列を平面的に密に配列することにより、３倍密度振動子配置を有し７方向（準）同時探知が可能な超音波送受波器ひいては魚群探知機を、実現している。しかしながら、この先提案技術にもなお、改善すべき箇所がある。
【００２３】
まず、先提案技術における受波用配線の空間的繰返し間隔は、振動子の列数でいうと６列に亘っている。例えば図１６でいうと、受波用配線２４−Ａ１又は２４−Ａ２に接続されている振動子１２の列から、右に３列目の列の振動子１２は受波用配線２４−Ａ３又は２４−Ａ４に、更に右に３列目の列の振動子１２は受波用配線２４−Ａ１又は２４−Ａ２に、接続されている。従って、例えば受波用配線２４−Ａ１に接続された振動子１２が並ぶ列は、図１６中の左右方向に沿って、６列（幅＝３Ｄ）間隔で出現している。他の受波用配線、他のアレイについても（他のアレイの場合配線の傾きが変わるが）同様である。このように６列間隔で結線されていること、また列の間隔が均一であることにより、各受波用配線による受波出力から充分な信号利得で任意の受信ビーム（ビームＢＭ０を除く）を合成するには、６通りの移相制御信号値、即ち表１に示したπ、±２π／３、±π／３、０という６通りの移相量を適宜選択的に用いる必要が生じる。制御の簡単化ひいては実施の容易化のためには、できれば、移相量を６通りにも亘って切り換える制御を不要にしたい。
【００２４】
本発明は、このような問題点を解決することを課題としてなされたものであり、多面魚群探知機やサーチライト式魚群探知機に対して上記先提案技術が有する利点を引き続き確保しつつ、当該先提案技術に比べて移相制御信号値の種類が少なく、従ってより容易且つ低コストで実現可能な超音波送受波器、超音波送受波装置及び魚群探知機を得ること、更には超音波振動子をより隙間無く配置できるようにすることを、その目的としている。
【００２５】
【課題を解決するための手段】
このような目的を達成するために、本発明に係る超音波送受波器は、（１） その輻射面が互いに同面積でかつπ／３［ｒａｄ］の鋭角頂点を有し更に所定の振動子配列規則に従い平面的に配列された１２個以上の超音波振動子と、所定の励振側結線規則に従い上記超音波振動子に接続された第１及び第２励振用配線と、所定の受波側結線規則に従い上記超音波振動子に接続された第１乃至第１２受波用配線とを備え、（２）上記振動子配列規則が、上記輻射面の鋭角頂点同士が点集合し鈍角頂点同士が点集合するよう上記超音波振動子をその輻射方向を揃えて密に配列する、という規則であり、（３）上記励振側結線規則が、その鋭角頂点が同一点に集合している超音波振動子同士を上記第１励振用配線により接続し、更にこの第１励振用配線により接続された超音波振動子のいずれかと辺接触している超音波振動子同士を上記第２励振用配線により接続する、という単位結線を、超音波振動子の配列平面上で空間的に繰り返す、という規則であり、（４）上記受波側結線規則が、上記単位結線における超音波振動子の１２通りの相対位置に対して上記第１乃至第１２受波用配線を１対１に対応付け、それぞれその相対位置に対応した受波用配線に各超音波振動子を接続する、という規則であることを特徴とする。
【００２６】
また、本発明に係る超音波送受波装置は、（１）本発明に係る超音波送受波器と、（２）上記超音波送受波器に対し上記第１及び第２励振用配線を介して超音波送信用の駆動信号を供給する送信側の回路であって、上記第１及び第２励振用配線に対して互いに同相の信号を供給するか互いに逆相の信号を供給するかを切り換えることにより送信ビームの方向を設定する手段を含む回路と、（３）上記超音波送受波器から上記第１乃至第１２受波用配線を介して超音波受波による受信信号を受け取る受信側の回路であって、上記第１乃至第１２受波用配線を介する各受信信号にπ／２、π、０及び−π／２［ｒａｄ］のうちいずれかの移相量を選択的に割り当て、割り当てた移相量による各受信信号の移相処理並びにその後の各受信信号の相互結合処理を実行することにより、受信ビームの本数及び方向を設定又は選択する手段を含む回路と、を備えることを特徴とする。送信側の回路は、例えば、（４）送信側の回路が、上記第１及び第２励振用配線に対して互いに同相の信号を供給する同相励振動作と、互いに逆相の信号を供給する逆相励振動作とを、送信繰返し周期に比べ十分短い実行間隔を以て、交互に実行する手段を含み、また、（５）逆相励振動作実行時に、上記第１及び第２励振用配線に供給する駆動信号の周波数を調整することにより、送信ビームの方向を変化させる手段を含む。
【００２７】
そして、本発明に係る魚群探知機は、（１）船舶に搭載され、水面下における魚群に関する情報を映像表示する表示器を備える魚群探知機であって、（２）本発明に係る超音波送受波装置を備え、更に、（３）上記超音波送受波器を上記船舶の船底に固定したことを特徴とする。
【００２８】
ここに、本発明に係る超音波送受波器は、同じ形状を有する多数の超音波振動子を平面的に配列したこと、これらの超音波振動子を所定の振動子配列規則に従い配列したこと、２種類の励振用配線と１２種類の受波用配線を設けたこと、各超音波振動子に対する励振用配線及び受波用配線による結線をそれぞれ所定の規則に従い行うこと、の各点にて、先に説明した先提案技術と共通点を有している。また、その駆動・受信動作においても、第１及び第２励振用配線に対して互いに同相の信号を供給するか互いに逆相の信号を供給するかを切り換えることにより送信ビームの方向を定めること、同相励振動作及び逆相励振動作を短時間間隔で準同時に実行できること、逆相励振動作実行時に駆動信号の周波数を調整することにより送信ビームの方向を変化させることができること、第１乃至第１２受波用配線からの受信信号に同相／逆相／その中間の移相量による移相処理及び相互結合処理を施すことにより受信ビームの方向を設定・選択すること、船舶に搭載される魚群探知機において用いうること等の点において、先に説明した先提案技術と共通点を有している。これらのことによって、本発明においては、多面式やサーチライト式に対して先提案技術が有していた長所を、引き続き実現している。
【００２９】
本発明においては、超音波振動子形状、振動子配列規則、励振側結線規則及び受波側結線規則を工夫・変更することにより、受信ビーム合成の際の移相量を先提案技術における６通りから４通りに減らしている。また、本発明における超音波振動子配列においては、超音波振動子の輻射面形状が菱形であるため、超音波振動子をより密に配置できる。
【００３０】
まず、同一寸法及び同一形状の菱形が多数あるとする。また、この菱形の４個の角のうち２個がπ／３［ｒａｄ］、残りの２個が２π／３［ｒａｄ］であるとする。従って、任意の点に鋭角の頂点を６個寄せ集めるか鈍角の頂点を３個寄せ集めると２π［ｒａｄ］となり、その点の周りがそれぞれ６個又は３個の菱形で埋まる。このことに着目し、本発明においては、超音波振動子の輻射面形状（超音波を輻射する端面の形状）を、その４個の角のうち２個がπ／３［ｒａｄ］で他の２個が２π／３［ｒａｄ］である菱形とし、平面上における振動子配列規則を、輻射面の鋭角頂点同士が点集合し鈍角頂点同士が点集合するように隙間無くかつ輻射方向をそろえて超音波振動子を配置する、という規則にしている。従って、本発明においては、超音波振動子を平面上に密に、即ち（振動子間遮音材を除けば）隙間なしに配置できる。なお、本願では“密に配置”“点集合”等の言葉を使用しているけれども、それは本発明の構成を理解しやすく表現するためであり、超音波振動子間の結合を防ぐため遮音材を超音波振動子間に挟むことを禁ずる又は排する趣旨ではない。このことは、本願を参照する熟練した技術者にとっては、容易かつ一意に理解できるであろう。
【００３１】
更に、上掲の形状・寸法の輻射面を有する超音波振動子を上掲の振動子配列規則に従い配列すると、その配列内にいくつかの基本的繰り返しパターンが現れる。本発明で着目しているのは１２個の菱形を含む正六角形の繰り返しパターンである。即ち、任意の点にその鋭角頂点が集まり六芳星をかたちづくっている６個の菱形と、この六芳星を縁取っているかのようにこの６個の菱形のいずれかに対して辺同士が接触している他の６個の菱形とを含み、その辺の長さが各振動子の輻射面の辺の２倍である正六角形が、上掲の振動子配列規則による超音波振動子配列内で空間的に繰り返し現れる。そこで、本発明における結線規則は、励振側・受波側共に、この正六角形における結線を単位結線として超音波振動子の配列平面上で空間的に繰り返す、という規則にしている。また、繰り返される正六角形が１２個の超音波振動子を含んでいるため、本発明の好適な実施形態では１２の自然数倍の個数の超音波振動子を用いるが、１２で割り切れない個数の超音波振動子を用いても構わない。
【００３２】
また、繰返しの単位となっている正六角形は、その中央にある鋭角頂点集合点に対して回転対称であり、その点の回りにはπ／３［ｒａｄ］の角度周期で即ち６回、同一配列パターンが現れる。更に、この正六角形を、上述のように六芳星状に集まった中央の６個と、その縁取りに当たる外縁の６個とに区画することができる。そこで、本発明においては、励振側結線規則として、六芳星をかたちづくる中央の超音波振動子同士を第１励振用配線により接続する一方、縁取りに当たる外縁の超音波振動子同士を第２励振用配線により接続する、という励振側結線規則を採用している。第１励振用配線を介して供給する駆動信号と、第２励振用配線を介して供給する駆動信号とを、同相にすれば真正面を向いた１本の送信ビームが形成され、逆相にすれば振動子配置間隔及び波長により定まる角度だけ傾いた方向を向く送信ビームが（正六角形の各頂点に対応して）全アレイ合計で６本同時形成される。即ち、先提案技術と同様、準同時に形成可能な７本の送信ビームが得られる。
【００３３】
更に、繰返しの単位となっている正六角形は１２個の超音波振動子を含んでいる。本発明においては、１２種類の受波用配線を設け、これら第１乃至第１２受波用配線を、繰返しの単位となっている上述の正六角形或いはその結線である単位結線における超音波振動子の１２通りの相対位置に対して、それぞれ１対１に対応付け、それぞれその相対位置に対応した受波用配線に各超音波振動子を接続する、という受波側結線規則を用いている。従って、先提案技術と同様に移相回路や結合回路を設けることによって、７本の受信ビームを同時に又は選択的に使用して受信を行うことが可能である。また、先提案技術では、繰返しの単位である不等辺六角形における受波用配線の出現間隔が６列間隔であったが、本発明においては繰返しの単位である正六角形における受波用配線の出現間隔が４列間隔となる。列の間隔も均一である。そのため、各アレイの受信ビームを実現しつつ各アレイ受波出力同士の結合処理により受信利得を確保するには、先提案技術では移相制御信号値が６通り必要であったが、本発明においてはπ／２、π、０及び−π／２［ｒａｄ］の４通りですむ。
【００３４】
従って、本発明によれば、上記先提案技術に比べて移相制御信号値の種類が少なくなり、従ってより容易且つ低コストで魚群探知機等の超音波送受波装置を実現できる。超音波振動子の配置においては更に隙間を減らすことができる。
【００３５】
【発明の実施の形態】
以下、本発明の好適な実施形態に関し図面に基づき説明する。なお、本発明を実施するに当たっては、先に説明した先提案技術における回路を、移相制御信号値の内容を表１に示したものから次の表２に示すものへと変更するのみで、そのまま利用できる。そのため、以下の説明では先に説明した回路を前提とし、重複説明を排することとする。先に説明した回路と異なる回路では本発明を実施できない、という趣旨ではない。また、以下の各図中におけるＸ，Ｙ，Ｚの各軸や各ビームの名称は、図２２（ｂ）にて定義したものである。
【００３６】
【表２】

図１に、本発明の一実施形態における振動子配列規則、即ち配列平面上における振動子１２Ａの配列に関する規則を示す。図中、符号Ａ，Ｂ，Ｃが付されている菱形は本実施形態に係る超音波送受波器を構成する振動子１２Ａの輻射面であり、符号Ａ，Ｂ，Ｃはその符号が付されている振動子１２Ａが超音波振動子アレイＡ，Ｂ，Ｃのいずれに属しているのかを表している。振動子１２Ａの輻射面とは超音波送受波に使用される面であり、ここでは正電極１４又は負電極１６が形成されている面を指している。図２に示すように、菱形輻射面の４個の角のうち鋭角である２個は６０［°］即ち２π／３［ｒａｄ］であり、鈍角である残りの２個はπ／３［ｒａｄ］である。菱形輻射面の寸法は、例えば長軸方向＝２／（３）^１／２・λ、短軸方向＝２／３・λとなるよう設計する（λ：波長）。ビーム方向θを変更・制御するため、駆動信号周波数の切換即ち波長λの切換／可変制御を行うこともできる。また、任意の振動子１２Ａとその隣の振動子１２Ａとの間には、それらの間の音響的結合を防ぐため、平板状の遮音材１０Ａを挟み込む。
【００３７】
単純に幾何学的に考えると、図２に示した形状を有する振動子１２Ａをその輻射方向をそろえて密に配列する方法には、いくつかの方法がある。本実施形態においては、その中で、（１）鋭角頂点同士を集める、（２）鈍角頂点同士を集める、という２通りの規則に従い振動子１２Ａを配列する方法を、採用している。この方法に従い振動子１２Ａを配列すると、各振動子１２Ａの辺の２倍の長さの辺を有する正六角形を亀甲状に、即ち空間的に繰り返して配置した配列が現れる。この正六角形の中央には、６個の菱形の鋭角頂点が寄り集まった点がある。この６個の菱形のアウトラインはちょうど六芳星を描いている。図１中で最も下の位置に描かれている正六角形でいうと、上下に２個並んだ「Ａ」、向かって左上から右下にかけ袈裟懸けに並んだ「Ｂ」、並びに向かって右上から左下にかけ袈裟懸けに並んだ「Ｃ」という６個の菱形がこれに当たる。また、この六芳星アウトラインには窪んだ点が６カ所あり、それらの点には、それぞれ、六芳星の一部である２個の菱形と他の１個の菱形の鈍角頂点が集まっている。図１中で最も下の位置に描かれている正六角形でいうと、０時に位置している「Ａ」の上端の鋭角頂点から時計回りに「Ｂ」「Ａ」「Ｃ」「Ｂ」「Ａ」「Ｃ」の順で、６個の菱形が六芳星アウトラインの窪みを埋め正六角形外縁を形成している。
【００３８】
本実施形態における励振側及び受波側結線規則も、その中央に位置する六芳星アウトラインの部分と、その外縁を埋めて正六角形アウトラインを形成させる外縁部分とを含み、１２個の振動子１２Ａにより構成されたこの正六角形を単位としている。即ち、この正六角形内に含まれる１２個の振動子に対する励振用配線及び受波用配線の結線が、単位結線として、上掲の亀甲状繰返しに従い空間的に繰り返される。
【００３９】
まず、励振側結線規則、即ち励振用配線２２−１及び２２−２と振動子１２Ａとの接続に関する規則は、図３に示すように、六芳星アウトライン部分を構成する６個の振動子１２Ａには励振用配線２２−１を接続し、外縁部分を構成する６個の振動子１２Ａには励振用配線２２−２を接続する、という規則である。図３（及び後に引用する図４〜図６）では、結線規則を示すという目的から記載を簡略化し、振動子１２Ａを円形で示している。本実施形態における励振側結線規則が有している性格のうち、内側振動子同士を接続する一方外側振動子同士を接続する、という性格は、振動子配列こそ異なるが、先提案での励振側規則も備えていたものである。そのため、図１９（ｂ）及び（ｃ）に示したものと同じ原理により、送信ビームを切り換えることができる。即ち、励振用配線２２−１を介して印加する駆動信号ＴＸ１と励振用配線２２−２を介して印加する駆動信号ＴＸ２とを同相にすることにより、送信ビームを輻射面に直交する方向（真正面方向）とすることができ、逆相とすることにより、真正面方向に対して同角度傾いた６本の送信ビームを得ることができる。なお、逆相励振時における送信ビーム形成面は、上記正六角形の最長対角線と平行で輻射面に直交する面である。
【００４０】
次に、受波側結線規則、即ち受波用配線２４−Ａ１〜２４−Ａ４，２４−Ｂ１〜２４−Ｂ４，２４−Ｃ１〜２４−Ｃ４と振動子１２Ａとの接続に関する規則は、繰返しの単位である正六角形内における振動子１２Ａの位置に対して１対１に受波用配線を対応付け、相対応する振動子１２Ａと受波用配線２４とを接続する、という規則である。図４〜図６に、理解の助けとなるようアレイ毎に分けて、受波側結線規則を示す。これらの図に示されているように、上述の正六角形内には１２個の振動子１２Ａが含まれているため受波用配線も１２種類（２４−Ａ１〜２４−Ａ４，２４−Ｂ１〜２４−Ｂ４，２４−Ｃ１〜２４−Ｃ４）必要になる。各受波用配線２４−Ａ１〜２４−Ａ４，２４−Ｂ１〜２４−Ｂ４，２４−Ｃ１〜２４−Ｃ４による受波出力ＲＸＡ１〜ＲＸＡ４，ＲＸＢ１〜ＲＸＢ４，ＲＸＣ１〜ＲＸＣ４に対しては、先に掲げた表２に従い、また図２４〜図２７に示した回路により、移相処理、結合処理等が施される。それによって、受信利得を確保しつつ、合計７本の受信ビームを同時形成できる。
【００４１】
受波側結線規則において注目すべき点は、先に説明した振動子配列規則を採用していることと相俟って、空間的繰返し周期が振動子１２Ａの列でいうと４列であること、である。例えば、受波用配線２４−Ａ１に接続されている振動子１２Ａが並んでいる列は、図４に示すように、Ｘ軸の正方向に沿って４列周期で現れる。また、列の間隔は均一（図１に示した間隔設定下ではλ／２）である。これらは、受波用配線２４−Ａ２〜２４−Ａ４でも同様である。振動子アレイＢ，Ｃにおいても、図５及び図６に示すようにＺ軸周りに±２π／３［ｒａｄ］回転させた方向に沿って、同様の空間的繰返しが現れる。先提案技術では繰返し周期が６列であり列間隔が均一であったため６通りの移相制御信号値が必要であったが、本実施形態では引き続き列間隔が均一であるが繰返し周期が４列に減ったため、移相制御信号値は４通り（π，±π／２，０）でよい。
【００４２】
図７〜図１２に、本実施形態に係る装置にて実現したビームの例を示す。まず、図７及び図８に示す指向性パターンは、それぞれ、信号ＴＸ１及びＴＸ２を逆相としたときにＸＺ平面にて形成される送信ビームと、そのとき形成される６本の送信ビームの俯瞰とを、示している。次に、図９及び図１０に示す指向性パターンは、信号ＴＸ１及びＴＸ２を同相としたときにＸＺ平面にて形成される送信ビームと、そのとき形成される１本の送信ビームの俯瞰とを、示している。更に、図１１及び図１２に示す指向性パターンは、ＢＭＡ１に係る受波系統出力における指向性パターンであり、それぞれＸＺ平面におけるビームと、その俯瞰とを示している。
【００４３】
本発明の実施に当たっては、様々な変形が可能である。例えば、信号ＴＸ１にて励振される振動子１２Ａについては正電極１４が輻射方向を向き負電極１６が背面を向くよう配置し、信号ＴＸ２にて励振される振動子１２Ａについては正電極１４が背面を向き負電極１６が輻射方向を向くよう配置して、輻射方向側にある電極を励振用配線２２により接続し背面側にある電極を受波用配線２４により接続するようにしてもよい。このようにした場合、信号ＴＸ１及びＴＸ２が同相であるときには６個のビームが形成され、逆相であるときには１個のビームが形成される。この場合、表２とは若干異なる移相量による移相処理が必要になるが、本願の開示を参照した同分野の技術者にとっては、この点は自明であろう。また、ある振動子１２Ａとその周囲の振動子１２Ａとを直列接続して振動子アレイにシェーディングを施すようにしてもよい。更に、逆相励振／合成に限らず、一般に異相励振／合成を行うことができる。その場合、振動子１２Ａの中心間隔を、駆動信号間位相差に応じてずらす。同相励振／合成と逆相励振／合成とを使用者からの指令で又は適当な周期で自動的に切り換えるようにしてもよい。更に、複数の受信ビームを全て同時に合成するのではなく必要なビームだけを使用してもよい。同一の移相回路をあるときには第１のビームの合成に使用し他の場合には第２のビームの合成に使用するといった切換を随時行うようにしてもよい。また、本発明に係る超音波送受波器をＺ軸の回りに機械的に回転できる機構を設けることによって、斜め方向の探知範囲を固定６方向から更に拡大できる。そして、本発明は、魚群探知機の一部を構成する超音波送受波器に限定適用されるものではない。即ち、多数の方向を同時に探知・監視する必要乃至要請がある分野であれば、本発明に係る超音波送受波器乃至超音波送受波装置を適用できる。そのような例としては、例えば潮流計がある。更に、多面魚群探知機を構成する各超音波送受波器や計量型魚群探知機等に使用される超音波送受波器を、本発明に係る構成としてもよい。
【図面の簡単な説明】
【図１】 本発明の一実施形態における振動子配列規則を示すＸＹ平面図である。
【図２】 この実施形態における振動子の形状を示す図であり、特に（ａ）は斜視外観図、（ｂ）は輻射面形状図である。
【図３】 この実施形態における励振側結線規則を示すＸＹ平面図である。
【図４】 この実施形態における受波側結線規則のうち振動子アレイＡに関連する部分を示すＸＹ平面図である。
【図５】 この実施形態における受波側結線規則のうち振動子アレイＢに関連する部分を示すＸＹ平面図である。
【図６】 この実施形態における受波側結線規則のうち振動子アレイＣに関連する部分を示すＸＹ平面図である。
【図７】 この実施形態に係る装置にて得られたビームの一例をＸＺ平面にて示す指向特性図である。
【図８】 図７に示したビームを俯瞰的に示す指向特性図である。
【図９】 この実施形態に係る装置にて得られたビームの他の一例をＸＺ平面にて示す指向特性図である。
【図１０】 図９に示したビームの一例を俯瞰的に示す指向特性図である。
【図１１】 この実施形態に係る装置にて得られたビームの更に他の一例をＸＺ平面にて示す指向特性図である。
【図１２】 図１１に示したビームの一例を俯瞰的に示す指向特性図である。
【図１３】 先提案技術における超音波送受波器の構成を示す図であり、特に（ａ）は振動子配置を示すＸＹ平面図、（ｂ）は振動子収納状態を示すＩ−Ｉ断面図である。
【図１４】 この先提案技術における正三角形格子パターンを概念的に示すＸＹ平面図である。
【図１５】 この先提案技術における繰返しパターンを概念的に示すＸＹ平面図である。
【図１６】 この先提案技術における振動子アレイＡに係る受波用配線の接続パターンを概念的に示すＸＹ平面図である。
【図１７】 この先提案技術における振動子アレイＢに係る受波用配線の接続パターンを概念的に示すＸＹ平面図である。
【図１８】 この先提案技術における振動子アレイＣに係る受波用配線の接続パターンを概念的に示すＸＹ平面図である。
【図１９】 この先提案技術における励振側及び受波側結線規則を示す図であり、特に（ａ）は振動子アレイＡの構成を示すＸＹ平面図、（ｂ）は同相励振時等位相面及び送信ビームを示すＸＺ平面図、（ｃ）は逆相励振時等位相面及び送信ビームを示すＸＺ平面図である。
【図２０】 先提案技術における励振側及び受波側結線規則、特に振動子アレイＢの構成を概念的に示すＸＹ平面図である。
【図２１】 先提案技術における励振側及び受波側結線規則、特に振動子アレイＣの構成を概念的に示すＸＹ平面図である。
【図２２】 先提案技術及び本発明の実施形態におけるビーム指向性を概念的に示す図であり、特に（ａ）はＸＺ平面図、（ｂ）はＸＹ平面投影図である。
【図２３】 同相／逆相時間差励振を示すタイミングチャートである。
【図２４】 魚群探知機の全体構成を示すブロック図である。
【図２５】 送受切換器の構成を示す回路図である。
【図２６】 ビーム合成回路の構成を示すブロック図である。
【図２７】 結合器の構成を示すブロック図である。
【図２８】 移相処理の実現手法を示す回路図である。
【符号の説明】
１２Ａ 振動子、２２−１，２２−２ 励振用配線、２４−Ａ１，２４−Ａ２，…２４−Ｃ４ 受波用配線、２６ 制御回路、２８，３０ 駆動信号発生回路、３６ 超音波送受波器、４０ ビーム合成回路、５２ 送受切換器、Ａ，Ｂ，Ｃ 振動子アレイ、ＢＭＡ１，ＢＭＡ２，…ＢＭ０ ビーム、Ｄ 振動子中心間隔、ＬＳ１−１〜ＬＳ１−１２，ＬＳ２−１〜ＬＳ２−１２，…ＬＳ７−１〜ＬＳ７−１２ 移相制御信号、ＲＸＳ１〜ＲＸＳ１２ 増幅された受信信号、Ｓ１，Ｓ２ 駆動信号、Ｔ０ 送信繰返し周期、Ｔ１ 同相励振期間、Ｔ２ 逆相励振期間、Ｔ３ 同相逆相励振時間差、ＴＸ１，ＴＸ２ 増幅された駆動信号。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic transducer that can be used in an ultrasonic transducer such as a fish finder, an ultrasonic transducer and a fish finder using the ultrasonic transducer.
[0002]
[Prior art]
The fish finder is useful as a device that supports the operation of fishing boats. A fish finder is a type of ultrasonic transmitter / receiver that uses an ultrasonic transmitter / receiver located on the bottom of the ship to transmit ultrasonic waves into the water and receive echoes from the fish school, etc. Is displayed on the display screen of the ship. Fish detectors include multifaceted fish detectors that can detect multiple directions, searchlight-type fish detectors, and the like, all of which have problems. First, the multifaceted fish finder directs the beam of one ultrasonic transducer among the multiple ultrasonic transducers provided on the bottom of the ship, and directs the beams of the remaining ultrasonic transducers directly below the bottom of the ship. Since the configuration is directed toward a direction inclined with respect to the direction, there are many ultrasonic transducers to be used, and there is a problem that the device component cost, the installation work cost, the installation space, and the like increase. In addition, since the searchlight type fish detector is configured to change the direction of ultrasonic transmission / reception by mechanically changing the direction of the ultrasonic transmitter / receiver, a plurality of directions cannot be observed simultaneously. Since the swing mechanism is necessary, the cost of equipment parts, installation work, maintenance, etc. and the required space for installation are large, sonar dome that houses the ultrasonic transducer and the swing mechanism is necessary, and the equipment parts cost increases. A mechanism for raising and lowering the sonar dome is necessary, and there are problems such as costs for equipment parts, installation work and maintenance, and a large installation space.
[0003]
Japanese Patent Application No. Hei 10-313774 (Japanese Patent Application Laid-Open No. 2000-147095) is known as a fish detector that can detect a plurality of directions and has few problems such as the above-described multifaceted fish detector and searchlight type fish detector. (Referred to as “prior proposal technology” below). The feature of the previously proposed technology is that a large number of transducers are arranged in a plane, and that the transducer arrangement, excitation-side connection, and reception-side connection are performed according to predetermined rules. -Realization of a 7-direction simultaneous detection type ultrasonic transducer.
[0004]
First, the vibrator arrangement rule in the previously proposed technique is a rule that the vibrators are arranged according to a regular triangular lattice pattern, as shown in FIGS. More specifically, an ultrasonic wave transmitter / receiver according to the previously proposed technique is provided in a substantially circular sound insulating body 10 formed of a sound insulating material such as a cork sheet or a closed cell sponge rubber sheet, as shown in FIG. The ultrasonic transducers 12 are accommodated at a center interval D. An opening is provided on one surface of the sound insulator 10, and each vibrator 12 is housed in this opening with the positive electrode 14 facing outward and the negative electrode 16 facing inward. Conductor wiring for electrically connecting the positive electrode 14 and the negative electrode 16 of the vibrator 12 to the outside is disposed inside or outside the sound insulating body 10. It is necessary to provide a waterproof structure such as a urethane rubber mold so that it can be used in water. Various structural members for supporting and reinforcing the sound insulating body 10 may be provided. The shape of the sound insulator 10 and the shape and number of the vibrators 12 are determined according to the necessary beam as long as the formation of the array described later is not hindered. As shown in FIG. 14, each transducer 12 is arranged at each lattice point 20 on an equilateral triangular lattice pattern 18 that is a virtual pattern assumed along the surface of the sound insulator 10. The regular triangular lattice pattern 18 is a lattice-like pattern whose regular unit whose side is D is a repeating unit, and the lattice point 20 is a vertex of the regular triangle that is the repeating unit. .
[0005]
Further, FIG. 15 shows the wiring rules for the excitation wiring in the previously proposed technique. The excitation wiring is a wiring for connecting the positive electrodes 14 of the vibrator 12 to each other and connecting them to the outside (a drive signal generation circuit described later). The excitation wiring includes an excitation wiring 22-1 for applying the drive signal TX1 and an excitation wiring 22-2 for applying the drive signal TX2. One of these is connected to the vibrator 12.
[0006]
Further, FIG. 16 to FIG. 18 show the connection rules of the receiving wiring in the previously proposed technique. The wave receiving wiring is a wiring for connecting the negative electrodes 16 of the vibrator 12 to each other and connecting them to the outside (a beam combining circuit described later). There are twelve types of receiving wires, ie, receiving wires 24-x1 to 24-x4 (x = A, B, C). The receiving wirings 24-A1 to 24-A4 are inclined along a straight line parallel to the Y axis, and the receiving wirings 24-B1 to 24-B4 are inclined 2π / 3 (rad) clockwise with respect to the Y axis. The receiving wirings 24-C1 to 24-C4 connect the vibrators 12 to each other along a straight line inclined 2π / 3 (rad) counterclockwise with respect to the Y axis along the straight line. Connect to the circuit on the receiving side. The vibrator 12 connected by the receiving wiring 24-xj (j = 1, 3) and the vibrator 12 connected by the receiving wiring 24-xk (k = j + 1) are on the same straight line, and They are located alternately. Further, the placement line of the vibrator 12 connected to the reception wiring 24-x1 or 24-x2 and the placement line of the vibrator 12 connected to the reception wiring 24-x3 or 24-x4 are 3D / They are located alternately at intervals of 2. Furthermore, each transducer 12 is connected to any one of the receiving wires, and any of the transducers 12 is not connected to two or more receiving wires. The signals extracted by the reception wirings 24-A1 to 24-A4, 24-B1 to 24-B4, and 24-C1 to 24-C4 are sequentially supplied to RXA1 to RXA4, RXB1 to RXB4, and RXC1 to RXC1, respectively. The symbol RXC4 is attached.
[0007]
FIG. 19 to FIG. 21 show connections that are units of repetition in the above connection rules, that is, unit connections. This unit connection includes an equilateral triangle with one side = 2D including six vibrators 12 connected by the excitation wiring 22-1 and twelve vibrators 12 connected by the excitation wiring 22-2. And a hexagon with a long side = 3D and a short side = D surrounding the regular triangle. The distance between the inner regular triangles of adjacent unit connections is distance = 3 ^1/2 D (center distance = 2 × 3 ^1/2 D) and uniform. The outer hexagon is a shape obtained by cutting out an equilateral triangle with one side = D from each vertex of an equilateral triangle with one side = 5D, and the outer hexagons in other unit connections adjacent to each other are in contact with each other at their short sides (their Share the short side). Further, in FIGS. 19 to 21, reference signs A, B, and C are given to the respective vibrators 12. This indicates to which of the three ultrasonic transducer arrays A, B, and C formed on the same plane each transducer 12 belongs. In the array to which the affiliation belongs, the vibrator 12 is selected from among the receiving wirings 24-A1 to 24-A4, the receiving wirings 24-B1 to 24-B4, and the receiving wirings 24-C1 to 24-C4. It depends on which one is connected.
[0008]
As shown in FIGS. 19B and 19C, excitation is performed depending on whether the vibrator group belonging to the inner regular triangle and the vibrator group belonging to the outer hexagon are excited in the same phase or in the opposite phase. The position of the equiphase surface and the direction of the transmission beam change accordingly. When excited in the same phase, the transmitted beam faces directly in front (θ = 0). Further, at the time of reverse phase excitation, a difference in ultrasonic propagation path length between the transducer 12 belonging to the inner regular triangle and the transducer 12 belonging to the outer hexagon.
[Expression 1]
L = interval between both vibrator groups × sin θ
= (3D / 2) × sin θ
about
[Expression 2]
L = ± λ / 2 = (3D / 2) × sin θ
Is the angle indicating the direction of the transmitted beam (λ: wavelength of the ultrasonic wave). Further, as apparent from the above equation, the transmission beam at the time of antiphase excitation appears in two directions symmetric with respect to the Z axis, and the direction θ is designed by design depending on how many times the transducer interval D is set to the wavelength λ. And the direction θ can be arbitrarily set / controlled during actual use by switching the frequency of the drive signal and hence the wavelength λ. Since the number of transmission beams at the time of reversed-phase excitation is 2 for each transducer array in this way, the total number is 6 for all transducer arrays. When the in-phase excitation and the anti-phase excitation are combined, a total of seven transmission beams are obtained. However, since the in-phase excitation and the anti-phase excitation cannot be performed simultaneously, these seven transmission beams should be formed quasi-simultaneously. It is said. That is, with respect to the transmission beam, as shown in FIG. 23 using the transducer array A as an example, a period T1 in which the signals TX1 and TX2 are in phase and a period T2 in the opposite phase are provided within a single transmission repetition period T0. The mode is switched from the former to the latter or from the latter to the former with a sufficiently short time interval T3, so that transmission can be executed simultaneously for the six directions and quasi-simultaneously for the seven directions including the front. Yes.
[0009]
The direction and the number of reception beams can be switched by phase shift control for each reception wiring. First, the phase shift processing is performed with the same phase shift amount for each of the signals RXx1 to RXx4 taken out by the receiving wires 24-x1 to 24-x4 for the ultrasonic transducer array x (x = A, B, C). By applying (or no phase shift), it is possible to synthesize a reception beam directed in the Z-axis direction (in-phase synthesis). In addition, the signals RXx1 and RXx2 are phase-shifted by, for example, π (rad), and the phase shift amount related to the signals RXx3 and RXx4 is 0 (rad), that is, there is no phase shift. Two reception beams facing can be synthesized (reverse phase synthesis). Further, by providing in parallel a phase shift circuit related to in-phase synthesis and a phase shift circuit related to reverse phase synthesis, a reception beam directed in the Z-axis direction and two reception beams having an opening angle θ with respect to the Z-axis. Can be synthesized at the same time, so that simultaneous detection can be performed in three directions. Since any one ultrasonic transducer array can be detected simultaneously in three directions in this way, when all three ultrasonic transducer arrays are combined, two beams with an opening angle θ × three transducer arrays One beam in the + Z-axis direction (common to each array) = seven simultaneous receptions can be performed using a total of seven beams.
[0010]
Specifically, as shown in FIG. 22 and Table 1, a total of seven phase shift circuits are provided corresponding to each reception beam, and the value of the phase shift control signal supplied to the i-th phase shift circuit is received. The amount of phase shift for each of the signals RXA1 to RXA4, RXB1 to RXB4, and RXC1 to RXC4 by supplying one of the phase shift control signals LSi-1 to LSi-12 according to the received beam. By controlling, the received signals related to these seven beams can be synthesized simultaneously. In addition, in order to secure the signal reception gain, the reception outputs from the reception wirings 24 other than the reception wirings 24 corresponding to the necessary reception beams are also combined with appropriate phase shift. For example, when the beam BMA1 is synthesized, as shown in Table 1, the received outputs from the two types of receiving wirings related to the transducer array A are phase-shifted in mutually opposite phases, and are transferred to the transducer arrays B and C. The received outputs from the remaining four types of receiving wires are phase-shifted by an intermediate phase shift amount corresponding to the positional relationship in the unit array, and the received outputs from the receiving wires are combined.
[0011]
[Table 1]

In Table 1 and FIG. 22, BM0 is a beam formed by in-phase excitation or in-phase synthesis in each transducer array, and faces the Z-axis direction. BMA1 and BMA2 are beams formed by antiphase excitation or antiphase synthesis in the transducer array A, and belong to the XZ plane. BMB1 and BMB2 are beams formed by antiphase excitation or antiphase synthesis in the transducer array B, and belong to a plane rotated by −2π / 3 (rad) around the Z axis with respect to the XZ plane. BMC1 and BMC2 are beams formed by antiphase excitation or antiphase synthesis in the transducer array C, and belong to a plane rotated by 2π / 3 (rad) around the Z axis with respect to the XZ plane. The Z-axis is directed in the direction directly below the bottom of the ship (the direction perpendicular to the opening forming surface, ie, the radiation surface in FIG. 1), and the X-axis and Y-axis belong to the radiation surface. The X axis is, for example, the bow direction.
[0012]
As described above, according to the previously proposed technique, seven-direction (quasi-) simultaneous detection can be performed. Further, since the vibrators 12 are arranged according to the equilateral triangular lattice pattern 18, the beam interval is uniform, and therefore, it is possible to observe all the water under the ship. Since the transducer density is relatively high, the size of the ultrasonic transducer as a whole when incorporated in the sound insulator 10 is only one transducer array even though it includes three transducer arrays. It is not much different from what it does not have. That is, low cost and space saving. In addition, as a result of the repeated arrangement, one set (two types) of excitation wiring is used. That is, there is no need to provide excitation wiring corresponding to each transducer array, and three transducer arrays A to C can be formed at low cost.
[0013]
FIG. 24 shows an overall circuit / functional configuration of the fish finder according to the previously proposed technique. A control circuit 26 composed of a CPU or the like supplies a reference oscillation signal and a signal for setting a frequency division ratio to the drive signal generation circuits 28 and 30, and generates a reference oscillation signal in the drive signal generation circuits 28 and 30. The drive signals S1 and S2 are generated at the timing shown in FIG. 23 by controlling the frequency division operation and further pulse-modulating the signal obtained by the frequency division. The power amplifiers 32 and 34 generate the above-described signals TX1 and TX2 by amplifying the corresponding ones of these drive signals S1 and S2, and supply them to the ultrasonic transducer 36. The ultrasonic transducer 36 has the configuration shown in FIGS. The ultrasonic transducer 36 is disposed on the bottom of the ship with the X axis in the bow direction and the Z axis in the depth direction (directly below the ship bottom), and radiates ultrasonic waves into the water according to the signals TX1 and TX2.
[0014]
The ultrasonic waves reflected by the underwater fish school and the like are received by the ultrasonic transducer 36 and converted into electrical signals. The obtained signals RXA1 to RXA4, RXB1 to RXB4, and RXC1 to RXC4 are amplified by the preamplifier unit 38 and supplied to the beam combining circuit 40 as signals RXS1 to RXS12. The beam synthesis circuit 40 synthesizes signals related to the beams BMA1, BMA2, BMB1, BMB2, BMC1, BMC2, and BM0 from these signals RXS1 to RXS12 under the control of the control circuit 26. The combined signals are supplied to seven reception processing circuits 42 provided for each beam. In the reception processing circuit 42, a TVG (time variable gain) circuit 44 performs correction processing for a decrease in the reflected echo level due to attenuation of ultrasonic wave propagation, and a detection circuit 46 converts the signal from the beam synthesis circuit 40 into a DC signal by detection. The AD converter 48 converts this DC signal from analog to digital and supplies it to the control circuit 26. Based on the digital signal supplied from each reception processing circuit 42, the control circuit 26 displays information such as the presence / absence of fish school and the scale in each direction on the screen of the display 50. The user can obtain the school of fish information about many directions by observing the screen display of the display device 50. In particular, the image composition processing inside the control circuit 26 can provide a three-dimensional image related to the underwater situation using the plurality of beams shown in FIG.
[0015]
A transmission / reception switching device 52 provided between the power amplifiers 32 and 34 and the preamplifier unit 38 and the ultrasonic transducer 36 automatically applies the negative electrode 16 of the vibrator 12 when the drive signals TX1 and TX2 are supplied. As a ground conductor, the receiving side circuit after the preamplifier unit 38 is substantially disconnected from the ultrasonic transducer 36. Otherwise, the positive electrode 14 of the vibrator 12 is automatically used as the ground conductor before the power amplifiers 32 and 34. This is a circuit for substantially separating the transmission side circuit from the ultrasonic transducer 36. In other words, the ultrasonic transducer 36 can be used substantially only as an ultrasonic transmitter when the drive signals TX1 and TX2 are supplied, and can be used only as an ultrasonic receiver otherwise. It is a circuit for making.
[0016]
FIG. 25 shows an example configuration of the transmission / reception switch 52. The transmission / reception switch 52 in this figure is composed of a transmission side circuit 54 and a reception side circuit 56. The transmission-side circuit 54 is provided between each of the power amplifiers 32 and 34 and the excitation wiring 22 corresponding thereto. This circuit 54 is connected between the corresponding power amplifier and the corresponding excitation wiring 22 and connected in reverse parallel to each other, and these diodes D1 and D2 on the ultrasonic transducer 36 side. A capacitor C connected to the end, an inductor L connected between the capacitor C and the ground, and diodes D3 and D4 parallel to the inductor L and antiparallel to each other. The values of the capacitor C and the inductor L are set so as to resonate in series at the carrier frequency of the signals TX1 and TX2, that is, the transmission frequency f0.
[0017]
On the other hand, the circuit 56 on the receiving side is provided between each of the reception wirings 24 of the ultrasonic transducer 36 and the preamplifier 58 corresponding thereto. The preamplifier unit 38 is composed of a total of 12 preamplifiers 58. The circuit 56 on the reception side is composed of diodes D5 and D6 that are connected to the ground and connected in antiparallel to each other.
[0018]
Therefore, during the period (T1 + T3 + T2 in FIG. 23) in which the drive signals TX1 and TX2 (strictly speaking, the transmission pulses therein) are supplied via the power amplifiers 32 and 34, both ends of the inductor L in the circuit 54 are connected. While being short-circuited, one end of each receiving wiring 24 is grounded in the circuit 56. In other periods, the capacitor C and the inductor L in the circuit 54 resonate due to the transmission frequency component in the received signal, so that the respective excitation wirings 22 are grounded at one end.
[0019]
The beam combining circuit 40 can be configured as shown in FIG. 26, for example. The beam combining circuit 40 shown in this figure has a signal RXS1 to a signal RXS1 to a coupler 62 provided corresponding to a total of seven beams to be combined together with a phase shift control signal which is an oscillation output of the local oscillation circuit 60. It has a configuration for inputting RXS 12. As shown in Table 1, the local oscillation circuit 60 generates a total of seven sets of phase shift control signals. That is, the phase shift control signals LS1-1 to LS1-12 for the combiner 62 corresponding to the beam BMA1, and the phase shift control signals LS2-1 to LS2-12 for the combiner 62 corresponding to the beam BMA2. ,... And phase shift control signals LS7-1 to LS7-12 are supplied to the couplers 62 corresponding to the beam BM0. Each phase shift control signal, for example, divides the reference oscillation signal supplied from the control circuit 26 by the division ratio set by the control circuit 26, and further sets the initial value of the counter used for this division. It can be generated by setting it appropriately shifted (giving an initial phase). The phase shift control signal generated in this way is a signal having the phase shift amount to be realized as its initial phase.
[0020]
Each coupler 62 is a circuit that operates as a phase shift circuit, and has a configuration shown in FIG. 27, for example. The coupler 62 shown in this figure includes a buffer 64 provided corresponding to each of the input signals RXS1 to RXS12, each of the signals RXS1 to RXS12 supplied via the buffer 64, and a phase shift control signal LSi− corresponding thereto. 1 to LSi-12 (i = 1, 2,... 7), a multiplier 66 that multiplies and couples, an adder 68 that adds and couples the outputs of each multiplier 66, and a band limit to the output signal of the adder 68 The BPF 70 extracts only the necessary frequency components.
[0021]
Each multiplier 66 includes an analog switch 72 and a BPF 74 as shown in FIG. The switch 72 is means for switching the signal RXSj in accordance with the supplied phase shift control signal LSi-j (j = 1, 2,... 12). For example, when the transmission frequency f0 is 50 kHz, a signal having a frequency of 505 kHz is supplied as the phase shift control signal LSi-j to perform switching, thereby obtaining a signal modulated according to the phase shift control signal LSi-j. This signal includes a sum frequency component, that is, 505 kHz + 50 kHz = 555 kHz, and a difference frequency component, that is, 505 kHz-50 kHz = 455 kHz, and its phase is determined by the initial phase of the phase shift control signal LSi-j. Yes. The BPF 74 passes the difference frequency component (the 455 kHz component in the above example) among the frequency components included in this signal. Since an initial phase corresponding to the phase shift amount to be realized is given to the phase shift control signal LSi-j, a signal phase shifted by the phase shift amount can be obtained from the BPF 74 and the multiplier 66.
[0022]
[Problems to be solved by the invention]
As described above, according to the previously proposed technique, a unit that becomes a repetitive unit by the vibrators arranged according to the predetermined vibrator arrangement rule and the exciting and receiving wirings connecting the vibrators according to the predetermined wiring rule. By forming an array and arranging this unit array densely in a plane, an ultrasonic transducer with a triple density transducer arrangement and capable of simultaneous detection in 7 directions (quasi), and thus a fish finder can be realized. is doing. However, there are still points to be improved in the proposed technology.
[0023]
First, the spatial repetition interval of the receiving wiring in the previously proposed technique is over 6 columns in terms of the number of transducer columns. For example, referring to FIG. 16, the transducers 12 in the third column to the right of the transducer 12 connected to the reception wire 24-A1 or 24-A2 are connected to the reception wire 24-A3 or The transducer 12 in the third column to the right of 24-A4 is connected to the wave receiving wiring 24-A1 or 24-A2. Therefore, for example, the rows in which the transducers 12 connected to the reception wiring 24-A1 are arranged appear at intervals of 6 rows (width = 3D) along the horizontal direction in FIG. The same applies to other receiving wirings and other arrays (although the inclination of the wiring changes in the case of other arrays). As described above, since the wires are connected at intervals of six rows and the intervals between the rows are uniform, an arbitrary received beam (excluding the beam BM0) is obtained with a sufficient signal gain from the received wave output from each receiving wiring. For synthesis, it is necessary to selectively use six phase shift control signal values, that is, six phase shift amounts of π, ± 2π / 3, ± π / 3, and 0 shown in Table 1. In order to simplify the control and thus to facilitate the implementation, it is desirable to eliminate the control for switching the amount of phase shift over six ways.
[0024]
The present invention has been made in order to solve such problems, and while continuing to ensure the advantages of the above-mentioned previously proposed technology over multifaceted fish finder and searchlight type fish finder, There are fewer types of phase shift control signal values compared to the previously proposed technology, and therefore, it is possible to obtain an ultrasonic transducer, an ultrasonic transducer and a fish detector that can be realized more easily and at a lower cost, and furthermore, an ultrasonic vibration Its purpose is to make it possible to arrange the children without any gaps.
[0025]
[Means for Solving the Problems]
In order to achieve such an object, an ultrasonic transducer according to the present invention includes: (1) radiation surfaces having the same area and having acute angle vertices of π / 3 [rad] and a predetermined transducer 12 or more ultrasonic transducers arranged in a plane according to the arrangement rule, first and second excitation wirings connected to the ultrasonic transducer according to a predetermined excitation side connection rule, and a predetermined receiving side (1) the first to twelfth receiving wirings connected to the ultrasonic transducers according to a connection rule, and (2) the transducer arrangement rule is configured such that the acute angle vertices of the radiation surface are point-set and the obtuse angle vertices are It is a rule that the ultrasonic transducers are densely arranged so that their radiating directions are aligned so as to collect points. (3) Ultrasonic vibration in which the excitation side connection rule has its acute-angle vertices gathered at the same point. The children are connected by the first excitation wiring, and the first excitation wiring is further connected. The unit connection of connecting the ultrasonic transducers that are in side contact with any of the ultrasonic transducers connected by using the second excitation wiring is spatially repeated on the arrangement plane of the ultrasonic transducers. (4) The reception-side connection rule has a one-to-one correspondence between the first to twelfth reception wirings with respect to 12 relative positions of the ultrasonic transducer in the unit connection. The rule is that each ultrasonic transducer is connected to a receiving wire corresponding to the relative position.
[0026]
The ultrasonic transducer according to the present invention includes (1) the ultrasonic transducer according to the present invention, and (2) the first and second excitation wires with respect to the ultrasonic transducer. A circuit on the transmission side for supplying a drive signal for ultrasonic transmission, wherein the first and second excitation wirings are switched between supplying signals having the same phase or signals having opposite phases to each other. And a circuit including means for setting the direction of the transmission beam by (3), and a circuit on the receiving side for receiving a reception signal by ultrasonic reception from the ultrasonic transducer through the first to twelfth reception wirings The phase shift amount of π / 2, π, 0, and −π / 2 [rad] is selectively assigned to each received signal via the first to twelfth receiving wirings and assigned. Phase shift processing of each received signal according to the amount of phase shift and subsequent interconnection of each received signal By executing the process, characterized in that it and a circuit including means for setting or selecting the number and direction of the reception beam. For example, the transmission-side circuit includes (4) an in-phase excitation operation in which the transmission-side circuit supplies in-phase signals to the first and second excitation wirings, and an inversion in which the in-phase signals are supplied to each other. And means for alternately executing the phase excitation operation with an execution interval sufficiently shorter than the transmission repetition period, and (5) driving to be supplied to the first and second excitation wirings when performing the reverse phase excitation operation. Means for changing the direction of the transmitted beam by adjusting the frequency of the signal;
[0027]
The fish finder according to the present invention is (1) a fish finder equipped with a display device that displays an image of information regarding fish under the surface of the water, and is (2) an ultrasonic transmission / reception device according to the present invention. And (3) the ultrasonic transducer is fixed to the bottom of the ship.
[0028]
Here, in the ultrasonic transducer according to the present invention, a number of ultrasonic transducers having the same shape are arranged in a plane, these ultrasonic transducers are arranged in accordance with a predetermined transducer arrangement rule, At each point of providing two types of excitation wiring and twelve types of reception wiring, and performing connection with each of the excitation wiring and reception wiring for each ultrasonic transducer according to a predetermined rule, It has similarities to the previously proposed technology described above. Also, in the driving / receiving operation, the direction of the transmission beam is determined by switching between supplying the signals having the same phase or the signals having the opposite phases to the first and second excitation wirings, The in-phase excitation operation and the anti-phase excitation operation can be executed quasi-simultaneously at short time intervals, the direction of the transmission beam can be changed by adjusting the frequency of the drive signal when the anti-phase excitation operation is executed, Setting and selecting the direction of the received beam by applying phase shift processing and mutual coupling processing based on the in-phase / reverse phase / intermediate phase shift amount to the received signal from the wave wiring, and a fish finder mounted on the ship In this respect, there are common points with the previously proposed technology described above. For these reasons, the present invention continues to realize the advantages of the previously proposed technology over the multi-face type and the searchlight type.
[0029]
In the present invention, by devising and changing the ultrasonic transducer shape, transducer arrangement rule, excitation-side connection rule, and reception-side connection rule, the amount of phase shift at the time of receiving beam synthesis is six ways in the previously proposed technique. It is reduced to 4 ways. Further, in the ultrasonic transducer arrangement according to the present invention, since the radiation surface shape of the ultrasonic transducer is a rhombus, the ultrasonic transducers can be arranged more densely.
[0030]
First, it is assumed that there are many rhombuses having the same dimensions and the same shape. Further, it is assumed that two of the four corners of the rhombus are π / 3 [rad] and the remaining two are 2π / 3 [rad]. Therefore, when 6 acute-angle vertices are gathered at an arbitrary point or 3 obtuse-angle vertices are gathered, 2π [rad] is obtained, and the circumference of the point is filled with 6 or 3 rhombuses, respectively. Focusing on this, in the present invention, the radiation surface shape of the ultrasonic transducer (the shape of the end surface that radiates ultrasonic waves) is 2 out of the four corners and π / 3 [rad] and the other Two diamonds are 2π / 3 [rad], and the arrangement rules of the oscillators on the plane are aligned so that the acute angle vertices of the radiating surface are point-set and the obtuse-angle vertices are point-set so that there is no gap between them. The rule is to arrange ultrasonic transducers. Therefore, in the present invention, the ultrasonic transducers can be arranged densely on a plane, that is, without a gap (except for the inter-vibrator sound insulating material). In the present application, the terms “closely arranged” and “point set” are used, but this is for easy understanding of the configuration of the present invention, and in order to prevent coupling between the ultrasonic transducers, a sound insulating material. Is not forbidden or excluded from being sandwiched between ultrasonic transducers. This will be easily and uniquely understood by a skilled technician referring to the present application.
[0031]
Further, when the ultrasonic transducers having the radiation surfaces of the above-mentioned shapes and dimensions are arranged according to the above-mentioned transducer arrangement rules, some basic repetitive patterns appear in the arrangement. The focus of the present invention is a regular hexagonal repeating pattern including 12 rhombuses. In other words, six rhombuses whose sharp vertices are gathered at an arbitrary point to form a six-pointed star, and either of these six rhombuses as if bordering the six-pointed star A regular hexagon that includes the other six diamonds in contact with each other and whose side length is twice the side of the radiation surface of each transducer is the ultrasonic vibration according to the transducer arrangement rule described above. Appears spatially repeated in the child array. Therefore, the connection rule in the present invention is such that both the excitation side and the reception side are spatially repeated on the arrangement plane of the ultrasonic transducer using the connection in the regular hexagon as a unit connection. In addition, since the regular hexagon to be repeated includes 12 ultrasonic transducers, the preferred embodiment of the present invention uses a number of ultrasonic transducers that is a natural number multiple of 12; An ultrasonic transducer may be used.
[0032]
In addition, the regular hexagon that is a repeating unit is rotationally symmetric with respect to the acute vertex set point at the center thereof, and is the same around the point with an angular period of π / 3 [rad], that is, six times. An array pattern appears. Furthermore, this regular hexagon can be partitioned into six pieces at the center gathered like a hexagonal star as described above and six pieces at the outer edge corresponding to the border. Therefore, in the present invention, as the excitation-side connection rule, the central ultrasonic transducers forming the hexagonal star are connected by the first excitation wiring, while the outer ultrasonic transducers corresponding to the edge are used for the second excitation. The excitation side connection rule of connecting by wiring is adopted. If the drive signal supplied via the first excitation wiring and the drive signal supplied via the second excitation wiring are in phase, a single transmission beam facing directly in front will be formed, and the drive signal supplied in reverse phase will be passed. For example, six transmission beams directed in the direction inclined by an angle determined by the transducer arrangement interval and wavelength (corresponding to each vertex of the regular hexagon) are formed in total for a total of six. That is, as in the previously proposed technique, seven transmission beams that can be formed quasi-simultaneously are obtained.
[0033]
Furthermore, the regular hexagon which is a repeating unit includes 12 ultrasonic transducers. In the present invention, twelve kinds of receiving wirings are provided, and the first to twelfth receiving wirings are ultrasonic transducers in the above-mentioned regular hexagon or a unit connection which is a connection unit thereof. The twelve relative positions are associated with each other in a one-to-one relationship, and a receiving-side connection rule is used in which each ultrasonic transducer is connected to a receiving wire corresponding to each relative position. Therefore, by providing a phase shift circuit and a coupling circuit as in the previously proposed technique, it is possible to perform reception using seven reception beams simultaneously or selectively. Further, in the previously proposed technique, the appearance interval of the receiving wiring in the unequal hexagon that is a repeating unit was 6 column intervals. However, in the present invention, the receiving wiring in the regular hexagon that is a repeating unit is used. The appearance interval is 4 column intervals. The spacing between the rows is also uniform. Therefore, in order to secure the reception gain by combining the reception signals of the arrays while realizing the reception beams of the arrays, the previously proposed technique requires six kinds of phase shift control signal values. There are four types of π / 2, π, 0, and −π / 2 [rad].
[0034]
Therefore, according to the present invention, the number of types of phase shift control signal values is reduced as compared with the above-described prior art, so that an ultrasonic transmission / reception device such as a fish finder can be realized more easily and at a lower cost. The gap can be further reduced in the arrangement of the ultrasonic transducers.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In practicing the present invention, the circuit in the previously proposed technology described above is simply changed from the one shown in Table 1 to the one shown in Table 2 below. Can be used as is. For this reason, in the following description, it is assumed that the circuit described above is a premise, and redundant description is omitted. This does not mean that the present invention cannot be implemented with a circuit different from the circuit described above. In addition, the names of the respective axes of X, Y, and Z and the respective beams in the following drawings are defined in FIG.
[0036]
[Table 2]

FIG. 1 shows a vibrator arrangement rule according to an embodiment of the present invention, that is, a rule regarding the arrangement of the vibrators 12A on the arrangement plane. In the figure, diamonds denoted by reference signs A, B, and C are radiation surfaces of the vibrator 12A constituting the ultrasonic transducer according to the present embodiment, and reference signs A, B, and C are assigned the reference numerals. It shows whether the transducer 12A belongs to the ultrasonic transducer array A, B, or C. The radiation surface of the vibrator 12A is a surface used for ultrasonic transmission / reception, and here refers to a surface on which the positive electrode 14 or the negative electrode 16 is formed. As shown in FIG. 2, of the four corners of the diamond-shaped radiation surface, two of the acute angles are 60 [°], that is, 2π / 3 [rad], and the other two that are obtuse are π / 3 [rad. ]. The dimension of the diamond radiation surface is, for example, the long axis direction = 2 / (3) ^1/2 Designed so that λ and minor axis direction = 2/3 · λ (λ: wavelength). In order to change and control the beam direction θ, the drive signal frequency can be switched, that is, the wavelength λ can be switched / variably controlled. Further, in order to prevent acoustic coupling between an arbitrary vibrator 12A and an adjacent vibrator 12A, a plate-shaped sound insulating material 10A is sandwiched.
[0037]
Considering simply in terms of geometry, there are several methods for densely arranging the vibrators 12A having the shape shown in FIG. 2 so that their radiation directions are aligned. In the present embodiment, a method of arranging the vibrators 12A according to two rules of (1) collecting acute-angle vertices and (2) collecting obtuse-angle vertices is adopted. When the vibrators 12A are arranged according to this method, an arrangement in which regular hexagons having sides twice as long as the sides of each vibrator 12A are arranged in a turtle shell shape, that is, spatially repeated. In the center of this regular hexagon, there is a point where the acute vertices of six rhombuses gathered together. These six rhombus outlines depict a six-pointed star. In the case of the regular hexagon drawn in the lowest position in FIG. 1, two “A” s are arranged vertically, “B” is lined up from the upper left to the lower right, and from the upper right. There are six diamonds “C” lined up in the lower left corner. In addition, the six-pointed star outline has six recessed points, and at those points, two rhombuses that are part of the six-pointed star and another obtuse vertex of one rhombus are gathered. Yes. In the case of the regular hexagon drawn in the lowest position in FIG. 1, “B”, “A”, “C”, “B”, “B”, “A”, “C”, “B”, “ In the order of “A” and “C”, six rhombuses fill the hollows of the six-pointed star outline to form a regular hexagonal outer edge.
[0038]
The excitation-side and receiving-side connection rules in this embodiment also include a hexagonal outline portion located at the center and an outer edge portion that fills the outer edge to form a regular hexagonal outline, and includes twelve transducers 12A. The unit is the regular hexagon formed by That is, the connection of the excitation wiring and the receiving wiring for the twelve vibrators included in the regular hexagon is spatially repeated as a unit connection in accordance with the above-described turtle shell-like repetition.
[0039]
First, the excitation-side connection rule, that is, the rule relating to the connection between the excitation wirings 22-1 and 22-2 and the vibrator 12A is shown in FIG. Is connected to the excitation wiring 22-1 and the six vibrators 12A constituting the outer edge portion are connected to the excitation wiring 22-2. In FIG. 3 (and FIGS. 4 to 6 cited later), the description is simplified for the purpose of showing the connection rule, and the vibrator 12A is shown in a circle. Among the characteristics of the excitation side connection rule in this embodiment, the characteristic of connecting the inner vibrators while connecting the outer vibrators is different in the vibrator arrangement, but the excitation side in the previous proposal There were also rules. Therefore, the transmission beam can be switched based on the same principle as shown in FIGS. 19B and 19C. That is, by making the drive signal TX1 applied via the excitation wiring 22-1 and the drive signal TX2 applied via the excitation wiring 22-2 in phase, the direction of the transmission beam orthogonal to the radiation surface (right front) By setting the phase to the opposite direction, six transmission beams inclined at the same angle with respect to the straight front direction can be obtained. The transmission beam forming surface at the time of reverse phase excitation is a surface that is parallel to the longest diagonal line of the regular hexagon and orthogonal to the radiation surface.
[0040]
Next, the receiving-side connection rules, that is, the rules regarding the connection between the receiving wirings 24-A1 to 24-A4, 24-B1 to 24-B4, 24-C1 to 24-C4 and the vibrator 12A are repeated. The rule is that the receiving wires are associated with the positions of the transducers 12A within the regular hexagon as a unit, and the corresponding transducers 12A and the receiving wires 24 are connected. FIG. 4 to FIG. 6 show reception-side connection rules for each array so as to help understanding. As shown in these figures, since the above-mentioned regular hexagon includes 12 vibrators 12A, 12 types of reception wirings (24-A1 to 24-A4, 24-B1 to 24-B1) are also included. 24-B4, 24-C1 to 24-C4) are required. For the reception outputs RXA1 to RXA4, RXB1 to RXB4, RXC1 to RXC4 by the reception wirings 24-A1 to 24-A4, 24-B1 to 24-B4, 24-C1 to 24-C4, In accordance with the listed Table 2, and by the circuits shown in FIGS. As a result, a total of seven reception beams can be simultaneously formed while ensuring a reception gain.
[0041]
What should be noted in the receiving-side connection rule is that, in combination with the adoption of the transducer arrangement rule described above, the spatial repetition period is four in terms of the column of the transducer 12A. . For example, a column in which the transducers 12A connected to the reception wiring 24-A1 are arranged appears in a cycle of four columns along the positive direction of the X axis as shown in FIG. The column spacing is uniform (λ / 2 under the spacing setting shown in FIG. 1). The same applies to the reception wirings 24-A2 to 24-A4. In the transducer arrays B and C, the same spatial repetition appears along the direction rotated ± 2π / 3 [rad] around the Z axis as shown in FIGS. In the previously proposed technique, the repetition cycle is 6 rows and the row spacing is uniform, and thus six kinds of phase shift control signal values are required. However, in this embodiment, the row spacing is still uniform but the repetition cycle is 4 rows. Therefore, the phase shift control signal value may be four (π, ± π / 2, 0).
[0042]
7 to 12 show examples of beams realized by the apparatus according to the present embodiment. First, the directivity patterns shown in FIGS. 7 and 8 are overhead views of the transmission beam formed in the XZ plane and the six transmission beams formed at that time when the signals TX1 and TX2 are out of phase, respectively. Is shown. Next, the directivity patterns shown in FIGS. 9 and 10 show a transmission beam formed in the XZ plane when the signals TX1 and TX2 are in phase, and an overhead view of one transmission beam formed at that time. Show. Furthermore, the directivity patterns shown in FIG. 11 and FIG. 12 are directivity patterns in the receiving system output according to BMA1, and each show a beam on the XZ plane and its bird's-eye view.
[0043]
In carrying out the present invention, various modifications are possible. For example, the vibrator 12A excited by the signal TX1 is arranged such that the positive electrode 14 faces the radiation direction and the negative electrode 16 faces the back, and the vibrator 12A excited by the signal TX2 has the positive electrode 14 on the back. May be arranged so that the negative electrode 16 faces the radiation direction, and the electrode on the radiation direction side is connected by the excitation wiring 22 and the electrode on the back side is connected by the reception wiring 24. In this case, six beams are formed when the signals TX1 and TX2 are in phase, and one beam is formed when the signals TX1 and TX2 are in phase. In this case, a phase shift process with a slightly different phase shift amount from that in Table 2 is required, but this point will be obvious to engineers in the same field with reference to the disclosure of the present application. Alternatively, a certain transducer 12A and the surrounding transducer 12A may be connected in series so that the transducer array is shaded. Furthermore, not only the reverse phase excitation / synthesis, but generally the different phase excitation / synthesis can be performed. In that case, the center interval of the vibrator 12A is shifted according to the phase difference between the drive signals. The in-phase excitation / synthesis and the reverse-phase excitation / synthesis may be automatically switched by a command from the user or at an appropriate period. Further, only the necessary beams may be used instead of combining a plurality of received beams all at the same time. Switching may be performed as needed, such that the same phase shift circuit is used for synthesizing the first beam in some cases and used for synthesizing the second beam in other cases. Further, by providing a mechanism capable of mechanically rotating the ultrasonic transducer according to the present invention around the Z axis, the oblique detection range can be further expanded from the fixed six directions. And this invention is not limitedly applied to the ultrasonic transducer which comprises a part of fish finder. In other words, the ultrasonic transducer / ultrasonic transducer according to the present invention can be applied to a field where there is a need or demand for detecting and monitoring a large number of directions simultaneously. An example of such is a tide meter. Furthermore, the ultrasonic transducers used in the ultrasonic transducers and the measurement type fish detectors constituting the multifaceted fish finder may be configured according to the present invention.
[Brief description of the drawings]
FIG. 1 is an XY plan view showing transducer arrangement rules according to an embodiment of the present invention.
FIGS. 2A and 2B are diagrams showing the shape of a vibrator in this embodiment, in particular, FIG. 2A is a perspective external view, and FIG. 2B is a radiation surface shape diagram;
FIG. 3 is an XY plan view showing excitation-side connection rules in this embodiment.
FIG. 4 is an XY plan view showing a portion related to the transducer array A in the receiving-side connection rule in this embodiment.
FIG. 5 is an XY plan view showing a portion related to the transducer array B in the receiving-side connection rule in this embodiment.
FIG. 6 is an XY plan view showing a portion related to the transducer array C in the receiving-side connection rule in this embodiment.
FIG. 7 is a directivity characteristic diagram showing an example of a beam obtained by the apparatus according to this embodiment on the XZ plane.
8 is a directivity characteristic diagram showing the beam shown in FIG. 7 in an overhead view.
FIG. 9 is a directional characteristic diagram showing another example of the beam obtained by the apparatus according to this embodiment on the XZ plane.
10 is a directional characteristic diagram showing an example of the beam shown in FIG.
FIG. 11 is a directional characteristic diagram showing still another example of a beam obtained by the apparatus according to this embodiment on the XZ plane.
12 is a directional characteristic diagram showing an example of the beam shown in FIG.
FIGS. 13A and 13B are diagrams showing a configuration of an ultrasonic transducer in the previously proposed technique, in particular, FIG. 13A is an XY plan view showing a transducer arrangement, and FIG. It is.
FIG. 14 is an XY plan view conceptually showing an equilateral triangular lattice pattern in the previously proposed technique.
FIG. 15 is an XY plan view conceptually showing a repetitive pattern in the previously proposed technique.
FIG. 16 is an XY plan view conceptually showing a connection pattern of wave receiving wirings related to the transducer array A in the previously proposed technique.
FIG. 17 is an XY plan view conceptually showing a connection pattern of wave receiving wirings related to the transducer array B in the previously proposed technique.
18 is an XY plan view conceptually showing a connection pattern of wave receiving wirings related to the transducer array C in the previously proposed technique. FIG.
19A and 19B are diagrams showing excitation-side and receiving-side connection rules in the previously proposed technique, in particular, FIG. 19A is an XY plan view showing the configuration of the transducer array A, and FIG. 19B is an equiphase surface during in-phase excitation; FIG. 4C is an XZ plan view showing a transmission beam, and FIG. 5C is an XZ plan view showing an equiphase surface and a transmission beam during reverse phase excitation.
FIG. 20 is an XY plan view conceptually showing the excitation-side and receiving-side connection rules in the previously proposed technique, in particular, the configuration of the transducer array B.
FIG. 21 is an XY plan view conceptually showing the excitation-side and receiving-side connection rules in the previously proposed technique, in particular, the configuration of the transducer array C.
FIGS. 22A and 22B are diagrams conceptually showing the beam directivity in the previously proposed technique and the embodiment of the present invention, and in particular, FIG. 22A is an XZ plan view, and FIG. 22B is an XY plane projection view.
FIG. 23 is a timing chart showing in-phase / reverse phase time difference excitation.
FIG. 24 is a block diagram showing the overall configuration of the fish finder.
FIG. 25 is a circuit diagram showing a configuration of a transmission / reception switch.
FIG. 26 is a block diagram showing a configuration of a beam combining circuit.
FIG. 27 is a block diagram showing a configuration of a coupler.
FIG. 28 is a circuit diagram showing a method for realizing phase shift processing;
[Explanation of symbols]
12A vibrator, 22-1, 22-2 excitation wiring, 24-A1, 24-A2,..., 24-C4 receiving wiring, 26 control circuit, 28, 30 drive signal generation circuit, 36 ultrasonic transducer , 40 beam synthesis circuit, 52 duplexer, A, B, C transducer array, BMA1, BMA2,... BM0 beam, D transducer center interval, LS1-1 to LS1-12, LS2-1 to LS2-12, ... LS7-1 to LS7-12 Phase shift control signal, RXS1 to RXS12 Amplified received signal, S1, S2 drive signal, T0 transmission repetition period, T1 In-phase excitation period, T2 Inverse-phase excitation period, T3 In-phase to anti-phase excitation time difference , TX1, TX2 Amplified drive signals.

Claims (5)

12 or more ultrasonic transducers whose radiation surfaces have the same area and have acute vertices of π / 3 [rad] and are arranged in a plane according to a predetermined transducer arrangement rule, and a predetermined excitation side connection First and second excitation wirings connected to the ultrasonic transducer according to a rule, and first to twelfth reception wirings connected to the ultrasonic transducer according to a predetermined reception side connection rule. ,
The vibrator arrangement rule is a rule that the ultrasonic vibrators are arranged densely with their radiation directions aligned so that acute angle vertices of the radiation surface are point-set and obtuse-angle vertices are point set,
In the excitation-side connection rule, ultrasonic transducers whose acute vertices are gathered at the same point are connected to each other by the first excitation wiring, and the ultrasonic transducers connected by the first excitation wiring are connected. It is a rule that the unit connection of connecting ultrasonic transducers that are in side contact with either one by the second excitation wiring is spatially repeated on the arrangement plane of the ultrasonic transducers,
The reception-side connection rule associates the first to twelfth reception wirings on a one-to-one basis with respect to the 12 relative positions of the ultrasonic transducer in the unit connection, and each corresponds to the relative position. An ultrasonic transducer according to the rule that each ultrasonic transducer is connected to a receiving wire. An ultrasonic transducer according to claim 1;
A circuit on the transmission side for supplying a driving signal for ultrasonic transmission to the ultrasonic transducer via the first and second excitation wirings, and for the first and second excitation wirings A circuit including means for setting the direction of the transmission beam by switching between supplying in-phase signals to each other or supplying signals in opposite phases to each other;
A reception-side circuit for receiving a reception signal by ultrasonic reception from the ultrasonic transducer via the first to twelfth reception wires, and each of the circuits via the first to twelfth reception wires. A phase shift amount of any one of π / 2, π, 0, and −π / 2 [rad] is selectively assigned to the received signal, the phase shift process of each received signal by the allocated phase shift amount, and each subsequent reception A circuit including means for setting or selecting a direction of a received beam by performing a signal mutual coupling process;
An ultrasonic transmission / reception apparatus comprising: The ultrasonic transmission / reception device according to claim 2,
The transmission-side circuit compares an in-phase excitation operation for supplying in-phase signals to the first and second excitation wirings and an anti-phase excitation operation for supplying signals in opposite phases to the transmission repetition period. An ultrasonic transmission / reception apparatus comprising means for alternately executing with a sufficiently short execution interval. The ultrasonic transmission / reception apparatus according to claim 2 or 3,
The transmission-side circuit includes means for changing the direction of the transmission beam by adjusting the frequency of the drive signal supplied to the first and second excitation wirings when the anti-phase excitation operation is performed. Ultrasonic transducer. In a fish finder equipped with a display mounted on a ship and displaying video information about fish under the surface of the water,
A fish finder comprising the ultrasonic transmission / reception device according to any one of claims 2 to 4, wherein the ultrasonic transmission / reception device is fixed to a bottom of the ship.

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