1328972 . 九、發明說明 【發明所屬之技術領域】 本發明是有關於一種超音波換能器，且特別是有關於由 兩種不同壓電材料的使用，將聲波激發與接收工作分開之聚 焦式超音波換能器’可簡化傳統換能器之電路設計，並透過 壓電材料電極的切割而形成陣列式換能器，搭配電路設計， 可因此控制入射聲波及接收試片的背向散射聲場，有利於試 _ 片缺陷的檢測’並可增加超音波掃瞄的效率。 【先前技術】 在超音波的工程應用上，聚焦式超音波換能器佔有相當 重要的地位。傳統非破壞性檢測中的超音波掃瞄系統 (c-Scan)與量測表面波波速的超音波顯微鏡（Ac〇ustic MiCroscopy)，都是使用此種聚焦式超音波換能器。近年來， 由於聚焦式超音波換能器更廣泛地應用在許多尖端技術領 域中，例如積體電路（1C)產品封裝的檢測、先進材料之材料 特性量測、醫學工程與生物組織的影像觀測、微裂縫與微缺 陷的檢/則等等，因而聚焦式超音波換能器也愈來愈朝向高頻 ^與2解析度的方向發展。另外，聚焦式超音波換能器在科學 H 研九上也疋項重要的工具，例如薄膜機械性質的測定、殘 2應力的分析等等。在這些應用中，超音波換能器扮演著非 常重要的角色，也因此一直是非常重要的一項研究課題。 聚焦式超音波換能器的種類报多，舉例而言，依聚焦的 里式，可以分為點聚焦與線聚焦；依壓電材料所在的位置， 1328972 可以分為有鏡頭式與無鏡頭式；依頻率之範圍，可以由數個 MHz到GHz ;依所使用之壓電材料，有氧化鋅（ZnO)、鈮酸 鋰（LiNb03)、錯鈦酸鉛（PZT)、聚氟化亞乙烯（PVDF)等等； 而依聲波激發與接收的元素個數，可分為單一元素（Single Element)換能器與陣列式（Array)換能器。 在目前的發展中’不管是工程上或是醫學上的應用，換 能器均有陣列化的趨勢’原因是陣列式的換能器可以提供電 子式掃描（Electric Scanning)、動態變焦（Dynamic Focusing) 以及超音波波束導引（Beam Steering)的功能。其中，陣列式 換能器的分類基本上可分成線性陣列（Linear Array)以及相 位陣列（Phased Array)兩類。線性陣列換能器的工作模式是 每次以相鄰元素個數為一個族群，由左而右依序激發元素族 群，並使用聚焦式透鏡，達到超音波在特定深度聚焦進行電 子式掃描的目的。在相位陣列中，以環狀陣列（Annular Array) 為例，其工作模式是透過陣列元素的延遲激發，達到聲波動 態變焦與聲波導引的功能。對於掃描系統而言，由於陣列式 換能器可大幅改善掃描的效率，因此可使超音波檢測獲得相 當大的進步。 請參照第丨圖，其係繪示一種傳統聚焦式超音波換能器 之裝置示意圖。傳統的聚焦式超音波換能器1〇〇是由壓電材 料，例如ρΖΤ、ζη〇、以及LiNb〇3等，配合超音波鏡頭ι〇2 構成單一元素的換能器。其令’超音波鏡頭1〇2之主體係由 高聲速低衰減的材料，例如石英、與氧化鋁晶體所構成並 在此主體之刖端上進行加工而形成一内凹的曲面激發BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an ultrasonic transducer, and more particularly to a focusing type that separates acoustic excitation from reception by the use of two different piezoelectric materials. The Ultrasonic Transducer simplifies the circuit design of the traditional transducer and forms an array transducer through the cutting of the piezoelectric material electrode. The circuit design can control the incident sound wave and the backscattered sound of the receiving test piece. Field, which is good for testing _ chip defect detection' and can increase the efficiency of ultrasonic scanning. [Prior Art] Focused ultrasonic transducers play an important role in the engineering applications of ultrasonic waves. Ultrasonic scanning systems (c-Scan) in traditional non-destructive testing and Ac〇ustic MiCroscopy in measuring surface wave velocity use such focused ultrasonic transducers. In recent years, focused ultrasonic transducers have been widely used in many cutting-edge technologies, such as the detection of integrated circuit (1C) product packaging, material property measurement of advanced materials, medical engineering and biological tissue imaging observation. , micro-cracks and micro-defects, etc., so the focus-type ultrasonic transducer is also increasingly moving toward the direction of high-frequency ^ and 2 resolution. In addition, the focused ultrasonic transducer is also an important tool in the scientific research, such as the measurement of the mechanical properties of the film, the analysis of the residual stress and so on. In these applications, ultrasonic transducers play a very important role and have therefore been a very important research topic. There are many types of focused ultrasonic transducers. For example, according to the focus, the focus can be divided into point focus and line focus. According to the position of the piezoelectric material, 1328972 can be divided into lens type and lensless type. Depending on the frequency range, it can be from several MHz to GHz; depending on the piezoelectric material used, there are zinc oxide (ZnO), lithium niobate (LiNb03), lead stannous acid (PZT), and polyvinylidene fluoride ( PVDF) and so on; and the number of elements excited and received by sound waves can be divided into single element transducers and array (Array) transducers. In the current development, 'transformers have an array trend, whether it is engineering or medical applications' because the array of transducers can provide electronic scanning (Electric Scanning), dynamic zoom (Dynamic Focusing) ) and the function of ultrasound beam steering (Beam Steering). Among them, the classification of array transducers can be basically divided into two types: linear array (Array Array) and phase array (Phased Array). The working mode of the linear array transducer is that each time the number of adjacent elements is a group, the element group is sequentially excited from left to right, and the focus lens is used to achieve the purpose of ultrasonic scanning at a specific depth. . In the phase array, an annular array (Annular Array) is used as an example. The mode of operation is to achieve the acoustic fluctuation zoom and sound guiding through the delayed excitation of the array elements. For scanning systems, because array transducers can greatly improve the efficiency of scanning, there is considerable advancement in ultrasonic testing. Please refer to the figure, which is a schematic diagram of a conventional focus type ultrasonic transducer. The conventional focused ultrasonic transducer 1 is a transducer composed of a piezoelectric material such as ρΖΤ, ζη〇, and LiNb〇3, which is combined with an ultrasonic lens ι〇2 to form a single element. The main system of the 'ultrasonic lens 1〇2 is composed of a material with high sound velocity and low attenuation, such as quartz, and an alumina crystal, and is processed on the end of the body to form a concave curved surface excitation.
/接收n m所送出之高電壓脈衝信號激發壓電層112，而 產生聲波’聲波再經由超音波鏡頭m之内凹曲面刚折射 後聚焦於偶合液m之中，而形成聚焦之人射聲場。此一入 射聲波在試片1〇6表面會有一部分折射進入試片1〇6之中， 其餘之聲波則在介面反射’再由超音波鏡帛1〇2之曲面ι〇4 收集後回到壓電層112’並產生反射之電壓信號。如果試片 106之體内具有缺陷，例如空孔刚或裂縫，或者有異質物 體，則入射之聲波會被散射（seattering)，部分散射之聲波會 再由超音波鏡頭102之曲面104回到壓電層112，產生額外 之背向散射（back scattering)信號。一般的超音波掃描與超 音波影像，都是利用背向散射信號，得到試片内部的資訊。 另外，也有一種無鏡頭式的聚焦式超音波換能器。請參 照第2圖，其係繪示另一種傳統聚焦式超音波換能器之裝置 示意圖。在聚焦式超音波換能器200申，係以壓電材料，例 如PVDF，直接在外罩202之前端形成具有内凹之曲面的壓 電層204。激發/接收器214所送出之高電壓脈衝信號經過/ receiving the high voltage pulse signal sent by nm to excite the piezoelectric layer 112, and generating the acoustic wave 'sound wave is then refracted through the concave curved surface of the ultrasonic lens m and then focused on the coupling liquid m to form a focused human sound field . This incident sound wave will be partially refracted into the test piece 1〇6 on the surface of the test piece 1〇6, and the remaining sound waves will be reflected in the interface and then collected by the surface ι〇4 of the ultrasonic mirror 帛1〇2. The piezoelectric layer 112' produces a reflected voltage signal. If the test piece 106 has defects in the body, such as a hole or a crack, or a foreign object, the incident sound wave will be scattered, and the partially scattered sound wave will be returned to the pressure by the curved surface 104 of the ultrasonic lens 102. Electrical layer 112 produces an additional backscattering signal. In general ultrasonic scanning and ultrasonic imaging, the backscattering signal is used to obtain information inside the test piece. In addition, there is also a lensless focus type ultrasonic transducer. Referring to Figure 2, there is shown a schematic diagram of another conventional focused ultrasonic transducer device. In the focused ultrasonic transducer 200, a piezoelectric material, such as PVDF, is formed directly on the front end of the outer cover 202 to form a piezoelectric layer 204 having a concave curved surface. The high voltage pulse signal sent by the excitation/receiver 214 passes
次毫米波陣列接頭2 12後，再經由訊號線208傳送至壓電層 204，以激發壓電層204來產生聲波，聲波接著聚焦於偶合 液210之中’而形成聚焦之入射聲場。此入射聲波在試片 206表面會有一部分折射進入試片206之中，其餘之聲波則 在介面反射，而回到壓電層204，並產生反射之電壓信號。 此反射之電壓信號經由訊號線208，再通過次毫米波陣列接 頭212後而回傳至激發/接收器214»這種型式的聚焦式超 音波換能器200 ’其最大的優點是沒有鏡面上固體/液體的 8 1328972 穿射、反射與折射現象，而係直接利用訊號線咖 電層204與次毫来波陣列接頭212，因此 連接愿 利於後續的聲學分析。另外，壓電層2〇4之:;乂選用直=有 其優點是PVDF與水所構成之偶合液21〇的聲學阻抗 近’因此兩者之間有良好之聲學阻抗匹配。 :刀接 頭式的超音波換能器200的製程較容15無鏡 可以有許多種變化。 且裝置彈性較大， 傳統聚焦式超音波換能器最大的問題在於 卓-壓電層’因此入射聲場為固定的，缺 I: 機械式的上下位移改變入射聲場的聚焦位置。另外需= 射信號是由所有回到壓電層的聲波共同疊加而成， 分屋電層上所有反射的聲波’才能得到一個單一的輸出产 號。然而’這樣的一個輸出信號無法反應或重建出完整㈣ 向散射_場’㈣得到之背向散射聲場隱含有 缺陷或異質體的資訊’例如位置、大小、材質等等。因：内 利用傳統聚焦式超音波換能器所得到之超音波影像均只能 =:強弱大小構成’而欠缺對背向散射聲場更精密 【發明内容】 因此’本發明之目的就是在提供一種超音波換能器其 激發與接收之壓電元件分別設於鏡頭之頂端與底端，而可分 別供激發產生聲波與接收回傳之聲波訊號。故可使聲波的激 發與接收刀離’因而無需使用傳統複雜且昂貴的激發，接收 9 1328972 器° 本發明之另一目的是在 一 音波換能器，位A '、種了調控入射聲場的超 、 、士負責激發聲波之壓電元件切叼成所外夕 聲波激發陣列，每一個 °所6又汁之 路，因於( nt)配置獨立之激發電 路，因此可利用觸發時序， 了調控入射聲場之換能器。 之又—目的是在提供一種可接收空間 散射聲場的超音波換萨哭尨料甘A主 ^ 、曰及換此ι§，係對其負責接收聲波之壓電元件 電極^切割’形成特殊之電極圖形，透過上下電極的交錯區 域，疋義出多個小面積的聲波感測區，經由鏡頭與此接收陣 刃的接口 τ使換能器前端之内凹曲面上具有多個聲波感測 元素每個小面積之聲波感測區均類似於一個點接收源的 水中聽音器，集合所有聲波感測點所得到的資訊將可得到 相當豐富之背向散射聲場分佈與時域波形。因此，可實現陣 列式超音波換能器的架構。 根據本發明之上述目的’提出一種超音波換能器，至少 包括：一鏡頭’具有相對之頂面以及底面，其中底面設有内 凹之曲面；一第一壓電元件，設於前述鏡頭之頂面上；以及 一第一壓電元件’設於前述鏡頭之底面中的曲面上。 依照本發明一較佳實施例，上述之第一壓電元件係激發 壓電元件’且第二壓電元件係接收壓電元件，其中第一壓電 元件之壓電層的材料為壓電陶瓷，且第二壓電元件之壓電層 材料為高分子壓電材料。 依照本發明另一較佳實施例，上述之第一壓電元件可經 由切割而形成環形的聲波激發陣列，每個元素之心線電極與 10 1328972 地電極均為環形且上下相互對應β 依照本發明又一較佳實施例，上述第二壓電元件將由電 極切割的方式形成接收陣列’壓電元件的心線電極與地電極 均經切割形成特定的電極圖案，其電極圖案上下交錯重疊的 區域為聲波的感測元素，因此可形成複數個聲波感測區。 【實施方式】After the sub-millimeter wave array connector 2 12 is transmitted to the piezoelectric layer 204 via the signal line 208 to excite the piezoelectric layer 204 to generate sound waves, the sound waves are then focused into the coupling liquid 210 to form a focused incident sound field. The incident sound wave is partially refracted into the test piece 206 on the surface of the test piece 206, and the remaining sound waves are reflected at the interface, returning to the piezoelectric layer 204, and generating a reflected voltage signal. The reflected voltage signal is transmitted through the sub-millimeter wave array connector 212 via the signal line 208 and back to the excitation/receiver 214» This type of focused ultrasonic transducer 200' has the greatest advantage that there is no mirror surface. The solid/liquid 8 1328972 penetrating, reflecting and refraction phenomenon uses the signal line layer 204 and the sub-millimeter array connector 212 directly, so the connection is intended to facilitate subsequent acoustic analysis. In addition, the piezoelectric layer 2〇4:; 乂 select straight = has the advantage that the acoustic impedance of the coupling solution 21 PV between PVDF and water is close, so there is a good acoustic impedance matching between the two. : The process of the knife-type ultrasonic transducer 200 is more than 15 mirrors. There are many variations. Moreover, the device has a large elasticity, and the biggest problem of the conventional focused ultrasonic transducer is that the Zhuo-piezoelectric layer is thus fixed, and the incident sound field is fixed. I: The mechanical up and down displacement changes the focus position of the incident sound field. In addition, the = signal is superposed by all the sound waves returning to the piezoelectric layer, and all the reflected sound waves on the sub-floor can get a single output. However, such an output signal cannot reflect or reconstruct the complete (four) scatter field _ field (4). The backscattered sound field contains information about defects or heterogeneous bodies such as position, size, material, and the like. Because: the ultrasonic image obtained by using the traditional focused ultrasonic transducer can only be =: strong and weak size constitutes 'the lack of backscattering sound field is more precise. [Inventive content] Therefore, the purpose of the present invention is to provide The ultrasonic transducer of the ultrasonic transducer is respectively disposed at the top end and the bottom end of the lens, and can respectively be used for exciting the sound wave and receiving the returned sound wave signal. Therefore, the excitation and reception of the acoustic wave can be separated from the 'so that it does not need to use conventional complicated and expensive excitation, and the receiver 9 9328972 is received. Another object of the invention is to adjust the incident sound field in a sonic transducer, position A ' The super- and shi, the piezoelectric elements responsible for exciting the acoustic waves are cut into the outer acoustic wave excitation array, and each of the cations is etched. Since the (nt) is configured with an independent excitation circuit, the trigger timing can be utilized. A transducer that regulates the incident sound field. In addition, the purpose is to provide a supersonic wave-changing material that can receive the spatially scattered sound field, and to change the shape of the electrode of the piezoelectric element that is responsible for receiving the acoustic wave. The electrode pattern transmits a plurality of small-area acoustic sensing regions through the interlaced regions of the upper and lower electrodes, and has a plurality of acoustic wave sensing on the concave curved surface of the front end of the transducer via the interface τ of the lens and the receiving blade The acoustic sensing area of each small area of the element is similar to the underwater listening device of a point receiving source. The information obtained by collecting all the acoustic sensing points will obtain a rich backscattered sound field distribution and time domain waveform. Therefore, the architecture of the arrayed ultrasonic transducer can be realized. According to the above object of the present invention, an ultrasonic transducer includes at least: a lens having an opposite top surface and a bottom surface, wherein the bottom surface is provided with a concave curved surface; and a first piezoelectric element is disposed on the lens a top surface; and a first piezoelectric element 'on the curved surface in the bottom surface of the lens. According to a preferred embodiment of the present invention, the first piezoelectric element is a piezoelectric element and the second piezoelectric element is a piezoelectric element, wherein the piezoelectric layer of the first piezoelectric element is a piezoelectric ceramic. And the piezoelectric layer material of the second piezoelectric element is a polymer piezoelectric material. According to another preferred embodiment of the present invention, the first piezoelectric element can form a ring-shaped acoustic wave excitation array by cutting, and the core line electrode of each element and the electrode of 10 1328972 are both annular and corresponding to each other in the upper and lower sides. According to still another preferred embodiment of the present invention, the second piezoelectric element forms a region in which the core electrode and the ground electrode of the receiving array 'piezoelectric element are cut by the electrode to form a specific electrode pattern, and the electrode patterns are alternately overlapped. It is a sensing element of sound waves, so a plurality of acoustic sensing regions can be formed. [Embodiment]
本發明揭露一種超音波換能器，其進行激發與接收之壓 電兀件獨立分開，因此可簡化換能器之電路設計。此外，可 汉叶激發與接收之壓電元件的電極圖案，以形成激發之陣列 凡素與接收之圖案元素，並配合高壓脈衝激發陣列電路的設 =可使此超音波換能器具有在待測試片不同深度聚焦的功 能二因此可對待測試片進行不同深度的掃描檢測，而可有效 推算出待调m片内部的重要材料結才冓變化。為了使本發明之 敘述更加詳盡與完備’可參照下列描述並配合第3圖至第5 圖之圖示。 理論上’背向散射聲場可以視為人射聲場與試片體内材 料結構的交互作用結果，此一交互作用可以迭過應力波動學 的基本理論與數值方法的計算而加m因此如果 =或掌握人射聲場的特性，同時又能量測到背向散 场分佈與時域波形（time.dGmain wavefGm)，即可利用 :方式，#到試片體内缺陷或異質體的量化資訊。 本發明提供-種超音波換能器，可控制入射聲場，並可 里測到#向散射的聲場分佈與時域波形。 請 > 照帛3圖，其繪示依照本發明一較佳實施例的一種 超音波換能器之裝置示意圖。超音波換能器3〇〇主要係由鏡 頭302以及二壓電元件3〇4與308所組成。鏡頭3〇2通常係 為柱狀體結構’且具有相對之頂面334與底面336。鏡頭3〇2 之材質通常採用尚聲速低衰減的材料，例如石英與氧化鋁晶 體。鏡頭302主體的底面336中，更利用加工方式而形成有 内凹的曲面306,以利聲波之聚焦。壓電元件3〇4係設置在 鏡頭302之頂面334上，其中壓電元件3〇4係為鍍有上下電 極且極化過的壓電陶瓷材料，心線電極設為壓電元件3〇4 之上電極。另一方面，壓電元件3〇8則係設置在鏡頭3〇2 之底面336中的曲面3 06上，壓電元件3 〇8則為鍍有上下電 極、經過極化過程之壓電高分子材料，心線電極係設為壓電 凡件308之上電極’如此可由下電極與超音波換能器3〇〇 之金屬外殼接合，以達到金屬屏蔽的作用，可減少雜訊的干 擾。 在本發明中’所提之兩種壓電元件，用在設計換能器 時’均可用來激發或接收聲波。然而，考慮此兩種壓電元件 的壓電特性、聲學阻抗匹配以及加工的因素，因此，本發明 之一較佳實施例中，壓電元件3〇4係作為激發用之壓電元 件’且壓電元件3〇4之壓電層的材質較佳係選用壓電陶瓷材 料’例如氧化鋅與锆鈦酸鉛，以提供或激發較強之入射聲 波’而壓電元件308則作為接收用之壓電元件，且壓電元件 3〇8之壓電層的材質較佳係選用高分子壓電材料，例如 PVDF ’以增加入射波的強度。由於Pvdf等高分子壓電層 12 1328972 之厚度約在十到數十微米之間，再加上這些高分子壓電材料 之聲學阻抗介於由石英等材料所組成之鏡頭3〇2與由水所 構成的偶合液之間，因此可作為匹配層，而可增加入射波的 強度》 ' 在此較佳實施例中，對壓電元件304之心線電極與地電 極進行切割，以使壓電元件304具有陣列圖案332，例如由 數個環型電極圖案排列成之環型陣列，每個陣列元素均具有 上下相互對應之環形電極，如第3Α圖之壓電元件3叫^上 視圖所示。在壓電元件3〇4中，每一組電極元素配置獨立之 激發電路，因此利用控制觸發各電極元素之時序能形成可 調控之入射聲場。 另一方面，請一併參照第3Β圖與第4圖，同樣可對壓 電元件308之心線電極318與地電極322進行切 線電極318與地電極322分別具有特殊之電極圖案3%與 328，如第3Β圖所示。在壓電元件3〇8中，心線電極The present invention discloses an ultrasonic transducer that is separately separated from the piezoelectric element that is excited and received, thereby simplifying the circuit design of the transducer. In addition, the electrode pattern of the piezoelectric element excited and received by the Hanye can be formed to form an array of excitation elements and received pattern elements, and the setting of the high voltage pulse excitation array circuit can make the ultrasonic transducer have The function of the different depth focusing of the test piece can therefore perform different depth scanning detection on the test piece, and can effectively calculate the important material knot change inside the m piece to be adjusted. In order to make the description of the present invention more detailed and complete, the following description can be referred to and in conjunction with the drawings of Figs. 3 to 5. Theoretically, the backscattered sound field can be regarded as the result of the interaction between the human sound field and the material structure in the test piece. This interaction can be superimposed on the basic theory of stress wave theory and the numerical method to calculate m. = or grasp the characteristics of the human sound field, and at the same time measure the back-scatter field distribution and time-domain waveform (time.dGmain wavefGm), you can use: way, # to the sample body defects or heterogeneous quantitative information . The present invention provides an ultrasonic transducer capable of controlling an incident sound field and measuring the sound field distribution and time domain waveform of the # scatter. Please refer to FIG. 3, which shows a schematic diagram of an apparatus for an ultrasonic transducer according to a preferred embodiment of the present invention. The ultrasonic transducer 3 is mainly composed of a lens 302 and two piezoelectric elements 3〇4 and 308. The lens 3〇2 is generally a columnar structure' and has an opposing top surface 334 and bottom surface 336. The material of the lens 3〇2 is usually made of a material that has a low attenuation of sound velocity, such as quartz and alumina crystals. In the bottom surface 336 of the main body of the lens 302, a concave curved surface 306 is formed by machining to facilitate focusing of the sound waves. The piezoelectric element 3〇4 is disposed on the top surface 334 of the lens 302, wherein the piezoelectric element 3〇4 is a piezoelectric ceramic material plated with upper and lower electrodes and polarized, and the core electrode is set as a piezoelectric element 3〇 4 Upper electrode. On the other hand, the piezoelectric element 3〇8 is disposed on the curved surface 306 in the bottom surface 336 of the lens 3〇2, and the piezoelectric element 3〇8 is a piezoelectric polymer plated with upper and lower electrodes and subjected to polarization. The material, the core wire electrode is set as the electrode on the piezoelectric component 308. Thus, the lower electrode can be joined to the metal casing of the ultrasonic transducer 3〇〇 to achieve the function of the metal shielding, and noise interference can be reduced. In the present invention, the two piezoelectric elements mentioned, when used in designing a transducer, can be used to excite or receive sound waves. However, considering the piezoelectric characteristics, acoustic impedance matching, and processing factors of the two piezoelectric elements, in a preferred embodiment of the present invention, the piezoelectric element 3〇4 is used as the piezoelectric element for excitation' The piezoelectric layer of the piezoelectric element 3〇4 is preferably made of a piezoelectric ceramic material such as zinc oxide and lead zirconate titanate to provide or excite a strong incident acoustic wave, and the piezoelectric element 308 is used for receiving. The piezoelectric element, and the piezoelectric layer of the piezoelectric element 3〇8 is preferably made of a polymer piezoelectric material such as PVDF' to increase the intensity of the incident wave. Since the thickness of the piezoelectric layer 12 1328972 such as Pvdf is about ten to several tens of micrometers, the acoustic impedance of these piezoelectric materials is between the lens 3〇2 composed of quartz and the like and the water. Between the coupling liquids formed, it can be used as a matching layer, and the intensity of the incident wave can be increased. In the preferred embodiment, the core electrode and the ground electrode of the piezoelectric element 304 are cut to make the piezoelectric The element 304 has an array pattern 332, for example, a ring array arranged by a plurality of ring-shaped electrode patterns, each array element having a ring electrode corresponding to each other up and down, as shown in the top view of the piezoelectric element 3 . In the piezoelectric element 3〇4, each set of electrode elements is provided with a separate excitation circuit, so that the timing of each electrode element can be controlled by control to form a controllable incident sound field. On the other hand, referring to FIG. 3 and FIG. 4 together, the tangential electrode 318 and the ground electrode 322 of the piezoelectric element 308 may have a special electrode pattern 3% and 328, respectively. , as shown in Figure 3. In the piezoelectric element 3〇8, the core electrode
之電極圖案326與地電極322之電極圖案328之位置上下交 錯’而這些交錯區域即為聲波感測區，因此可定義出多個： 面積之聲波感測元素330,如第4圖所示。由於壓電元件3〇8 3 06上，因此這些聲波 300之内凹曲面306 係設置在鏡頭302之底面336的曲面 的感測元素3 3 0分佈於超音波換能器 上’其中每一個聲波感測元素33〇類似一個點接收源的水中 聽音器。因此’集合壓電元# 308中所有之感測元素33〇 所收集之資訊，即可得到相當豐富的背向散射的聲場分佈盘 時域波形。 ^ 13 ^28972 透過壓電元件308之感測陣列設計，可使整體超音波換 能器300具有接收聲場空間分佈的能力，亦即具有空間解析 聲場的能力，因而可獲得更多的聲場資訊以利後端的理論分 析，進而得到有關待測物體内部缺陷更豐富的資訊。 在本發明中，係利用對壓電元件3〇4與3〇8之心線電極 與地電極進行切割的方式，來定義出壓電元件3〇4與3⑽ 之陣列元素。在本發明之一較佳實施例中，可例如利用準分 子雷射微結構加工系統來進行壓電元件3〇4與3〇8之電極的 切割。舉例而言，請參照第4圖，進行壓電元件3〇8之壓電 層320上下之心線電極318與地電極322之圖案切割加工 時，可利用準分子雷射束3丨〇，例如波長248nm之氟化氪 (KrF)準分子雷射束，其中此準分子雷射束31〇經過光罩 後，由反射鏡314改變其方向而將準分子雷射束31〇導向聚 焦透鏡3 16，例如十倍透鏡模組，而聚焦在欲定義之電極 上，並搭配四轴運動平台（未繪示）來進行心線電極318與地 電極322之圖案切割定義的工作。經過切割後，可分別在壓 電元件308之心線電極3丨8與地電極322上順利獲得特定的 電極圖案3 26與328,其感測元素33〇為心線電極318與地 電極322重疊的區域，因此可以製作出多個感測元素33〇。 這些感測元素330再分別與同轴電纜324連接，以將聲波訊 號回傳。 本發明之超音波換能器300在實際應用上，涉及以下的 研究領域：在聲場分析上，必須計算此超音波換能器300 在水中與固體中所形成之聲場，作為分析超音波換能器3〇〇 ^28972 :特性與進一步改善的依據；在電子電路方面，必須建立此 超音波換能器300的系統電路，包含多頻道的電壓脈衝產生 器以及訊號接收器。另外，需建立超音波換能器3〇〇之等效 電路模，進行電路模擬分析，並與實驗量測結果作比對， 从供了解各項參數，例如功率電晶體、壓電材料面積元素 個數、電路匹配料，對超音波換能器3〇〇功能的影響，來 找出最佳的設計。在實際應用上，超音波換能胃3〇〇係配合 _脈衝激發陣列354、伺服運動機構344、放大陣列多工器338 與不波器340等資料擷取系統、與控制單元342等等，如第 5圖所示之量測系統’才能測試所製作之超音波換能器则 在實際應用中的功能與特性。 在第5圖之量測系統中，聲波係利用與壓電元件 連接之脈衝激發陣列354來激發鏡頭302之頂面334上的壓 電元件304所產生，經過鏡頭3〇2之曲面3〇6、壓電元件 3〇8、水槽346中之偶合液348、試片35〇表面反射與内部 散射後，背向反射與散射回到超音波換能器3〇〇的聲波則由 壓電元件308接收，以完成聲波的量測。 由於本發明之超音波換能器300具有激發超音波之呈 環狀陣列的壓電7L件304以及接收反射訊號之呈球面接收 . 陣列的壓電元件308，因此可透過陣列元素、高壓脈衝產生 電路的設計，使得此陣列式超音波換能器3〇〇具有在待測試 片350不同深度聚焦的功能，而可對待測試片“ο進行不同 深度的掃描檢測，再由壓電元件3〇8之球面接收陣列、後端 故大電路的設計，收集到完整的背向散射聲場，進而推算待 15 更1 ^片350内部的重要材料結構變化例如缺陷gw。另外， 到的控2波在試片350内部的聚焦情形’從收集 時的 調得到最佳的聚焦特性，進而得到掃描 雖然，在上述之較佳實施例中，超音波換能器3〇〇且 分別用以激發鱼接收夕-廒Φ ，Λ 八有 、接收之一壓電兀件304與308。然而，值得 ’王意、的一點是，在本發明 不發月之另一實施例中，超音波換能器亦 隹在鏡頭之頂面上設置兼具激發與接收之壓電元件，其中 此壓電7L件之心、線電極與地電極經加I 士刀㈣而具有例如 由數個環型電極圖案排列成之環型陣列圖案，每個陣列元素 句/、有上下相互對應之環形電極，如同第3Α圖所示之壓電 几件304 一般。同樣地，藉由對此壓電元件中之每一組電極 元素配置獨立的激發電路，可利用控制觸發各電極元素之時 序，使超音波換能器能提供可調控之入射聲場。另一方面， 在本發明之再一實施例中，超音波換能器可同樣具有二壓電 元件为別設於鏡頭之頂面與底面，然設於鏡頭底面之壓電元 件係作為聲學阻抗匹配層，而設於鏡頭頂面之壓電元件仍肩 負激發與接收的責任，因此鏡頭底面之壓電元件之壓電層材 料係選用與傳播介質之聲學阻抗較為匹配之壓電高分子材 料，例如PVDF。如此一來，可有效改善機械波在偶合液與 下層壓電元件之間的聲學阻抗，進一步提升超音波換能器的 效能。於本發明之再一實施例中，超音波換能器可同樣具有 一壓電元件分別設於鏡頭之頂面與底面，底面之壓電元件為 聲學阻抗匹配層’然同樣可對鏡頭之頂面上所設置兼具激發 1328972 與接收之壓電元件心線電極與地電極進行加工切割，使其具 有例如由數個環型電極圖案排列成之環型陣列圖案，每個陣 列元素均具有上下相互對應之環形電極，如同第3A圖所示 之壓電元件3 04 —般。因此，同樣可藉由對此壓電元件中之 每一組電極元素配置獨立的激發電路，並利用控制觸發各電 極元素之時序，使超音波換能器能提供可調控之入射聲場， 並可由聲學匹配層的設計增加入射聲波的強度。 由上述本發明較佳實施例可知’本發明之一優點就是因 鲁為本發明之超音波換能器之激發與接收之壓電元件分別設 於鏡頭之頂端與底端，而可分別供激發產生聲波與接收回傳 之聲波sfl號’因此可使聲波的激發與接收分離，無需使用傳 統複雜且昂貴的激發/接收器，可簡化電路系統設計，降低 設備成本。 由上述本發明較佳實施例可知，本發明之另一優點就是 因為本發明之超音波換能器可將激發之壓電元件之電極切 割成所设計之圖案陣列，每一個電極元素配置獨立之激發電 • 路，因此可利用調控觸發時序，來設計入射聲場，具有不同 深度聚焦的功能’而可進行不同深度的掃描檢測。 • 由上述本發明較佳實施例可知，本發明之再一優點就是 • 因為本發明之超音波換能器可將接收之壓電元件加工成特 殊之電極圖形’而在鏡頭前端之内凹曲面上定義出多個小面 積的聲波感測元素，集合所有的感測元素，可得到相當豐富 之背向散射聲場分佈與時域波形，而藉此推算出待測物内部 結構之詳細資訊。 17 1328972 雖然本發明已以一較佳實施例揭露如上，然其並非用以 限定本發明，任何熟習此技藝者，在不脫離本發明之精神和 範圍内，當可作各種之更動與潤飾，因此本發明之保護範圍 當視後附之申請專利範圍所界定者為準。 【圖式簡單說明】 第1圖係繪示一種傳統聚焦式超音波換能器之裝置示 意圖。 〃 第2圖係繪示另一種傳統聚焦式超音波換能器之裝置 示意圖。 第3圖係繪示依照本發明一較佳實施例的一種超音波 換能器之裝置示意圖。 第3Α圖係繪示依照本發明一較佳實施例的一種超音波 換能器頂端之壓電元件的電極圖案示意圖。 第3B圖係繪示依照本發明一較佳實施例的一種超音波 換能器底端之壓電元件的電極圖案示意圖。 第4圖係繪示依照本發明一較佳實施例的一種超音波 換能器之壓電元件之電極圖案的製作示意圖。 第5圖係繪示依照本發明一較佳實施例的一種超音波 換能器之應用示意圖。 【主要元件符號說明】 1〇〇:超音波換能器 超音波鏡頭 1〇4 :曲面 1〇6 :試片 18 1328972The position of the electrode pattern 326 and the electrode pattern 328 of the ground electrode 322 is up and down' and the interlaced areas are the acoustic sensing areas, so that a plurality of: area acoustic wave sensing elements 330 can be defined, as shown in FIG. Due to the piezoelectric elements 3 〇 8 3 06, the concave curved surfaces 306 of the acoustic waves 300 are arranged on the curved surface of the lens 302. The sensing elements 3 3 0 are distributed on the ultrasonic transducers. The sensing element 33 is similar to a hydrophone of a point receiving source. Therefore, by collecting the information collected by all of the sensing elements 33 压电 in the piezoelectric element # 308, a fairly rich backscattered sound field distribution disk time domain waveform can be obtained. ^ 13 ^ 28972 Through the sensing array design of the piezoelectric element 308, the overall ultrasonic transducer 300 can have the ability to receive the spatial distribution of the sound field, that is, the ability to spatially resolve the sound field, thereby obtaining more sounds. The field information facilitates the theoretical analysis of the back end, and then obtains more information about the internal defects of the object to be tested. In the present invention, the array elements of the piezoelectric elements 3?4 and 3(10) are defined by cutting the core electrode and the ground electrode of the piezoelectric elements 3?4 and 3?8. In a preferred embodiment of the invention, the cutting of the electrodes of piezoelectric elements 3〇4 and 3〇8 can be performed, for example, using a quasi-molecular laser microstructure processing system. For example, referring to FIG. 4, when patterning of the core electrode 318 and the ground electrode 322 of the piezoelectric layer 320 of the piezoelectric element 3〇8 is performed, an excimer laser beam 3 can be used, for example, for example. A krypton fluoride (KrF) excimer laser beam having a wavelength of 248 nm, wherein the excimer laser beam 31 〇 passes through the reticle, and its direction is changed by the mirror 314 to guide the excimer laser beam 31 聚焦 to the focusing lens 3 16 . For example, a ten-fold lens module is focused on the electrode to be defined, and is matched with a four-axis motion platform (not shown) for the definition of the pattern cutting of the core electrode 318 and the ground electrode 322. After the dicing, the specific electrode patterns 3 26 and 328 can be smoothly obtained on the core electrode 3 丨 8 and the ground electrode 322 of the piezoelectric element 308, respectively, and the sensing element 33 〇 is the core line electrode 318 and the ground electrode 322 overlap. The area, so a plurality of sensing elements 33〇 can be produced. These sensing elements 330 are again coupled to coaxial cable 324 to return the acoustic signals. The ultrasonic transducer 300 of the present invention relates to the following research field in practical applications: in sound field analysis, the sound field formed by the ultrasonic transducer 300 in water and solid must be calculated as an ultrasonic wave for analysis. Transducer 3〇〇28796: characteristics and further improvement; in terms of electronic circuits, the system circuit of the ultrasonic transducer 300 must be established, including a multi-channel voltage pulse generator and a signal receiver. In addition, it is necessary to establish an equivalent circuit mode of the ultrasonic transducer 3〇〇, perform circuit simulation analysis, and compare with the experimental measurement results, from the parameters for understanding, such as power transistor, piezoelectric material area element The number of circuits, circuit matching materials, the impact of the 3 〇〇 function of the ultrasonic transducer to find the best design. In practical applications, the ultrasonic transducing stomach 3 配合 _ pulse excitation array 354, servo motion mechanism 344, amplification array multiplexer 338 and non-wave 340 data acquisition system, and control unit 342, etc. The measurement system shown in Figure 5 can test the functions and characteristics of the manufactured ultrasonic transducer in practical applications. In the measurement system of Figure 5, the acoustic wave is generated by a pulsed excitation array 354 coupled to the piezoelectric element to excite the piezoelectric element 304 on the top surface 334 of the lens 302, through the curved surface of the lens 3〇2. After the piezoelectric element 3〇8, the coupling liquid 348 in the water tank 346, and the surface of the test piece 35 are reflected and internally scattered, the sound waves that are back-reflected and scattered back to the ultrasonic transducer 3〇〇 are composed of the piezoelectric element 308. Receive to complete the measurement of the sound wave. Since the ultrasonic transducer 300 of the present invention has a piezoelectric 7L member 304 that excites an annular array of ultrasonic waves and a piezoelectric element 308 that receives a spherical receiving array of reflected signals, it can be generated by array elements and high voltage pulses. The circuit is designed such that the arrayed ultrasonic transducer 3 has the function of focusing at different depths of the sheet 350 to be tested, and the test piece can be subjected to different depth scanning detection, and then the piezoelectric element 3〇8 The design of the spherical receiving array and the back-end large circuit collects the complete backscattered sound field, and then estimates the important material structure changes such as the defect gw inside the chip. Further, the control 2 wave is The focusing condition inside the test strip 350 'obtains the best focusing characteristics from the adjustment at the time of collection, and thus the scanning is obtained. Although in the preferred embodiment described above, the ultrasonic transducers 3 are used to stimulate the fish reception. - 廒Φ, Λ 八有, receiving one of the piezoelectric elements 304 and 308. However, it is worthy of the point that in another embodiment of the present invention, the ultrasonic transducer is also in A piezoelectric element having both excitation and reception is disposed on the top surface of the head, wherein the core, the wire electrode and the ground electrode of the piezoelectric 7L member are provided with a ring formed by, for example, a plurality of ring-shaped electrode patterns by adding a knife (4) a pattern of arrays, each array element sentence, having a ring electrode corresponding to each other up and down, like a piezoelectric piece 304 shown in Fig. 3. Similarly, by each set of electrode elements in the piezoelectric element The independent excitation circuit is configured to control the timing of each electrode element to enable the ultrasonic transducer to provide a controllable incident sound field. On the other hand, in another embodiment of the present invention, the ultrasonic transducer The piezoelectric element may be disposed on the top surface and the bottom surface of the lens, and the piezoelectric element disposed on the bottom surface of the lens serves as an acoustic impedance matching layer, and the piezoelectric element disposed on the top surface of the lens is still excited and received. Responsibility, therefore, the piezoelectric layer material of the piezoelectric element on the bottom surface of the lens is selected from a piezoelectric polymer material that matches the acoustic impedance of the propagation medium, such as PVDF. Thus, the mechanical wave can be effectively improved in the coupling liquid. The acoustic impedance between the lower piezoelectric elements further enhances the performance of the ultrasonic transducer. In still another embodiment of the present invention, the ultrasonic transducer may have a piezoelectric element respectively disposed on the top surface of the lens and The piezoelectric element on the bottom surface and the bottom surface is an acoustic impedance matching layer. However, the core electrode and the ground electrode of the piezoelectric element and the receiving electrode can be processed and cut on the top surface of the lens to have, for example, a number. The ring-shaped electrode patterns are arranged in a ring-shaped array pattern, and each of the array elements has a ring electrode corresponding to each other up and down, like the piezoelectric element 3 04 shown in FIG. 3A. Therefore, the same can be used Each set of electrode elements in the electrical component is provided with an independent excitation circuit, and the timing of each electrode element is controlled by the control, so that the ultrasonic transducer can provide a tunable incident sound field, and the incident sound wave can be increased by the design of the acoustic matching layer. Strength of. According to the preferred embodiment of the present invention, one of the advantages of the present invention is that the piezoelectric elements that are excited and received by the ultrasonic transducer of the present invention are respectively disposed at the top and bottom ends of the lens, and can be separately excited. The sound wave is generated and the sound wave sfl number received back is transmitted. Therefore, the excitation and reception of the sound wave can be separated without using a conventional complicated and expensive excitation/receiver, which simplifies the circuit system design and reduces the equipment cost. According to the preferred embodiment of the present invention described above, another advantage of the present invention is that the ultrasonic transducer of the present invention can cut the electrodes of the excited piezoelectric element into a designed pattern array, and each electrode element is configured independently. The excitation circuit and the circuit can be used to design the incident sound field with different depth focusing functions, and the scanning detection can be performed at different depths. According to the preferred embodiment of the present invention described above, another advantage of the present invention is that the ultrasonic transducer of the present invention can process the received piezoelectric component into a special electrode pattern and has a concave curved surface at the front end of the lens. A plurality of small-area acoustic sensing elements are defined, and all the sensing elements are collected to obtain a rich backscattered sound field distribution and a time domain waveform, thereby deriving detailed information of the internal structure of the object to be tested. The present invention has been described above in terms of a preferred embodiment, and is not intended to limit the invention, and various modifications and changes may be made without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing a device of a conventional focus type ultrasonic transducer. 〃 Fig. 2 is a schematic diagram showing another device of a conventional focused ultrasonic transducer. Figure 3 is a schematic diagram of an apparatus for an ultrasonic transducer in accordance with a preferred embodiment of the present invention. Figure 3 is a schematic view showing an electrode pattern of a piezoelectric element at the top of an ultrasonic transducer in accordance with a preferred embodiment of the present invention. Figure 3B is a schematic view showing an electrode pattern of a piezoelectric element at the bottom end of an ultrasonic transducer in accordance with a preferred embodiment of the present invention. Fig. 4 is a view showing the fabrication of an electrode pattern of a piezoelectric element of an ultrasonic transducer according to a preferred embodiment of the present invention. Figure 5 is a schematic diagram showing the application of an ultrasonic transducer in accordance with a preferred embodiment of the present invention. [Main component symbol description] 1〇〇: Ultrasonic transducer Ultrasonic lens 1〇4: Surface 1〇6 : Test piece 18 1328972
108 ： 空孔 110 ： 112 ： 壓電層 114 ： 200 ： 超音波換能器 202 ： 204 ： 壓電層 206 ： 208 ： 訊號線 210 : 212 ： 次毫米波陣列接頭 214 ： 300 ： 超音波換能器 302 ： 304 ： 壓電元件 306 ： 308 ： 壓電元件 310 : 312 ： 光罩 314 : 316 ： 聚焦透鏡 318 : 320 ： 壓電層 322 : 324 ： 同軸電纜 326 ： 328 ： 電極圖案 330 ： 332 ： 陣列圖案 334 ： 336 ： 底面 338 ： 340 ： 示波器 342 ： 344 ： 伺服運動機構 346 ： 348 ： 偶合液 350 : 352 ： 缺陷 354 ： 偶合液 激發/接收器 外罩 試片 偶合液 激發/接收器 鏡頭 曲面 準分子雷射束 反射鏡 心線電極 地電極 電極圖案 感測元素 頂面 放大陣列多工器 控制單元 水槽 試片 脈衝激發陣列 19108 : Empty hole 110 : 112 : Piezoelectric layer 114 : 200 : Ultrasonic transducer 202 : 204 : Piezoelectric layer 206 : 208 : Signal line 210 : 212 : Submillimeter wave array connector 214 : 300 : Ultrasonic transducing 302: 304: piezoelectric element 306: 308: piezoelectric element 310: 312: photomask 314: 316: focusing lens 318: 320: piezoelectric layer 322: 324: coaxial cable 326: 328: electrode pattern 330: 332: Array pattern 334 : 336 : bottom surface 338 : 340 : oscilloscope 342 : 344 : servo motion mechanism 346 : 348 : coupling fluid 350 : 352 : defect 354 : coupling fluid excitation / receiver housing test piece coupling fluid excitation / receiver lens surface alignment Molecular laser beam mirror core electrode electrode electrode pattern sensing element top surface magnifying array multiplexer control unit sink test piece pulse excitation array 19