1280360 九、發明說明： 【發明所屬之技術領域】 本發明係關於一種光學式材料性質檢測裝置及檢測方 法，特別係關於一種利用雷射超音波之光學式材料性質檢 測裝置及檢測方法，其藉由縮小雷射光束之光點而可量測 微小物體。 【先前技術】 .表面超音波的激發與量測屬於傳統非破壞檢測的範疇， 已發展多年。對於超音波的產生與接收，目前多採用超音 波探頭（ultrasonic probe head)的方式。然而受限於接觸式探 頭的幾何形狀、尺寸以及使用材料耐用性的限制，接觸式 超音波檢測技術對於幾何形狀較為複雜的試片、微小的物 件、南溫環境等應用範嘴一直力有未逮。 相對於採用探頭式的偵測方式，光學式偵測不受幾何形 狀限制，偵測光點也沒有質量因而不受外在測試環境影 • 響’已成為新的超音波彳貞測研究領域的主要研究方向。雷 射超音波技術（laser ultrasonics)即為光學式超音波偵測技 術之一’其原理是將超音波之產生部分改用脈衝式雷射激 發器，利用雷射擊打試片表面產生的升溫引致試片表面發 生熱變形，因而產生彈性超音波。由於高頻與低頻的超音 波訊號在薄膜内部的傳遞速度不同，因此可以分析頻率與 速度的關係，再配合已知的物理模型反推得到薄膜材料的 機械性質與内部結構，例如：楊氏模數（Y〇ung，s 、 厚度及缺陷等。 10127 丨.doc 1280360 此項技術對於微機電（mems)產品之品質驗證能提供重 要幫助，因為微機械元件與傳統機械元件的製作方式不 同’通常藉由在半導體薄膜上蝕刻而形成微機械元件。由 於微機械元件元件之薄膜厚度很薄，無法用夾治具夾住以 傳統的拉伸試驗法進行楊氏模數量測。因此，發展量測 MEMS揚氏模數的量測技術遂成為一個重要的發展目標。 目前相關技術有：1 ·製作微小的測試結構，例如微懸臂樑 法（micro cantilever beam method)，其以壓力施加於微樑上 並由施力與變形關係推算機械性質，或量測微懸臂樑之共 振頻率再將共振頻率以理論模型推算楊氏模數，此法的缺 點是必須額外製作測試結構。2·以微壓針（nano in dent or)壓 於薄膜上’並以壓入深度與施力關係計算揚氏模數，此法 的缺點是量測不確定度大且僅可適用於軟性薄膜。 美國專利US 5,229,832揭示一種利用光學同頻干涉術 (homodyne interferometry)量測一試片表面絕對與相對振動 的方法，其係利用兩個干涉儀同時偵測水平（in，plane)及縱 向（out-of_plane)超音波振動訊號，當水平超音波振動訊號 由左至右位移時，第一光路徑26減少而第二光路徑27增 加，但總和近似不變。當縱向超音波振動訊號由上至下位 移時，第一光路徑26減少量等於第二光路徑27減少量，且 總和減少。US 5,229,832揭示之架構雖可同時偵測水平及縱 向超音波振動訊號，並減少對位不準（misalignment)，但並 未說明掘取材料性質之方法，且無法對微結構進行量測。 此外，US 5,229,832揭示之架構較為複雜，其使用兩個干涉 10127 丨.doc 1280360 儀也使製作成本相對提高。1280360 IX. Description of the Invention: [Technical Field] The present invention relates to an optical material property detecting device and a detecting method, and more particularly to an optical material property detecting device and a detecting method using laser ultrasonic waves, Small objects can be measured by reducing the spot of the laser beam. [Prior Art] The excitation and measurement of surface ultrasonic waves belong to the category of traditional non-destructive testing and have been developed for many years. For the generation and reception of ultrasonic waves, an ultrasonic probe head is currently used. However, due to the limitation of the geometry and size of the contact probe and the durability of the material used, the contact ultrasonic detection technology has always been applied to the application of the geometrical shape of the test piece, the tiny object, the south temperature environment and the like. catch. Compared with the probe type detection method, the optical detection is not limited by the geometry, and the detection spot has no quality and thus is not affected by the external test environment. It has become a new field of ultrasonic measurement research. The main research direction. Laser ultrasonics is one of the optical ultrasonic detection technologies. The principle is to change the generation of ultrasonic waves into pulsed laser exciters, and use the thunder to shoot the surface of the test piece to generate temperature rise. The surface of the test piece is thermally deformed, thereby producing elastic ultrasonic waves. Since the high-frequency and low-frequency ultrasonic signals have different transfer speeds inside the film, the relationship between frequency and speed can be analyzed, and the mechanical properties and internal structures of the film material can be obtained by inversely combining with known physical models, for example, Young's mode. Number (Y〇ung, s, thickness and defects, etc. 10127 丨.doc 1280360 This technology can be of great help for the quality verification of MEMS products because micromechanical components are made differently from traditional mechanical components. The micromechanical component is formed by etching on the semiconductor film. Since the film thickness of the micromechanical component component is very thin, it is impossible to clamp the Young's die by the conventional tensile test method by sandwiching the jig. Therefore, the development amount Measuring technology for measuring MEMS Young's modulus has become an important development goal. Currently related technologies are: 1) Making tiny test structures, such as the micro cantilever beam method, which is applied to the microbeams by pressure. The mechanical properties are estimated by the relationship between the force applied and the deformation, or the resonant frequency of the microcantilever is measured and then the resonant frequency is theoretically modeled. Calculating Young's modulus, the disadvantage of this method is that it is necessary to make additional test structures. 2. Press the nano in dent or on the film and calculate the Young's modulus by the relationship between the depth of penetration and the force applied. The disadvantage of the method is that the measurement uncertainty is large and can only be applied to a soft film. US Patent No. 5,229,832 discloses a method for measuring the absolute and relative vibration of a test piece surface by optical homo frequency interferometry. The two interferometers simultaneously detect horizontal (in, plane) and longitudinal (out-of-plane) ultrasonic vibration signals. When the horizontal ultrasonic vibration signal is displaced from left to right, the first optical path 26 is reduced and the second optical path is 27 Increase, but the sum is approximately unchanged. When the longitudinal ultrasonic vibration signal is displaced from top to bottom, the reduction of the first optical path 26 is equal to the reduction of the second optical path 27, and the sum is reduced. The architecture disclosed in US 5,229,832 can simultaneously detect Measuring horizontal and longitudinal ultrasonic vibration signals and reducing misalignment, but does not explain the method of excavating the properties of the material, and cannot measure the microstructure. In addition, US 5,229,8 The architecture revealed by 32 is more complicated, and its use of two interferences, 10127 丨.doc 1280360, also makes the production cost relatively high.
Coulette專人揭示一種應用雷射激發超音波於雙層材料 之鑑識技術（參考：Laser-generated ultrasound applied to two^layered materials characterization: semi-analytical model and experimental validation", Ultrasonic, 1993, vol, 3 6, page 239-243)，其揭示之鑑識技術係利用波長1〇64奈米 之Nd:YAG雷射產生脈衝雷射以激發試片，並使用 Mach-Zehnder heterodyne干涉儀在試片背面偵測超音波訊 號。之後，偵測之超音波訊號與解析模型比較評估，可應 用於雙層材料的鑑識。惟，Coulette等人揭示之架構在超音 波激發與接收方面係分別設置在試片的兩侧，所需測試空 間較大且試片不易夾持。 【發明内容】 本發明之主要目的係提供一種利用雷射超音波之光學式 材料性質檢測裝置及檢測方法，其藉由縮小雷射光束之光 點而可量測微小物體。 為達成上述目的，本發明揭示一種光學式材料性質檢測 裝置及其檢測方法。該光學式材料性質檢測裝置包含一可 產生一脈衝光束之超音波激發光源、一可承載一試片之載 台、一光學式超音波偵測器、一波形記錄器以及一處理器。 該超音波激發光源包含一雷射光源以及一設置於該脈衝光 束之光路上的聚焦透鏡，用以縮小該脈衝光束之光點尺 寸。該光學式超音波偵測器可偵測該脈衝雷射光束照射於 該試片所產生之表面超音波，該波形記錄.器可記錄該表面 101271.doc 1280360 超音波，而該處理器則根據該表面超音波計算該試片之材 料性質。 、本發明之光學式材料性質檢測方法藉由照射一脈衝光束 於一試片，並利用干涉術偵測該脈衝光束照射於該試片所 生之表面超曰波，記錄該表面超音波，再根據該表面超 曰波计算该试片之材料性質。根據該表面超音波計算該試 片之材料性質包含建構一實驗頻散曲線以及根據該實驗頻 散曲線與該表面超音波計算該試片之材料性質。該實驗頻 散曲線之建構方法可採用相位頻譜法，該實驗頻散曲線可 採用材料性質正算法，而計算該試片之材料性質可採用曲 線擬合法。 【實施方式】 囷1及圖2例示本發明之光學式材料性質檢測裝置1〇。該 光學式材料性質檢測裝置10包含一可產生一脈衝光束22之 超音波激發光源20、一可承載一試片32之載台30、一光學 式超音波偵測器40、一波形記錄器62以及一處理器64。該 超音波激發光源20係一脈衝雷射光源（例如Nd_YAG或 Ti-Saphire)，且該脈衝光束22係一脈衝雷射光束，其具有 小於100奈秒脈衝寬度。較佳地，該超音波激發光源20包含 一雷射光源24以及一設置於該脈衝光束22之光路上的聚焦 透鏡28，用以縮小該脈衝光束22之光點尺寸。該載台30係 一移動式載台，其可改變該脈衝光束22照射該試片32之位 置 圖2例示之光學式超音波偵測器40係一米若午（Mirau)干 101271.docCoulette has revealed a laser-generated ultrasound applied to two-layered materials characterization: semi-analytical model and experimental validation", Ultrasonic, 1993, vol, 3 6, Page 239-243), which discloses an identification technique that uses a Nd:YAG laser with a wavelength of 1〇64 nm to generate a pulsed laser to excite the test piece, and uses a Mach-Zehnder heterodyne interferometer to detect the ultrasonic wave on the back side of the test piece. Signal. After that, the detected ultrasonic signal is compared with the analytical model and can be applied to the identification of the two-layer material. However, the architecture disclosed by Coulette et al. is provided on both sides of the test piece in terms of ultrasonic excitation and reception, and the required test space is large and the test piece is not easily clamped. SUMMARY OF THE INVENTION A primary object of the present invention is to provide an optical material property detecting apparatus and a detecting method using laser ultrasonic waves, which can measure minute objects by reducing a spot of a laser beam. In order to achieve the above object, the present invention discloses an optical material property detecting device and a detecting method thereof. The optical material property detecting device comprises an ultrasonic excitation light source capable of generating a pulse beam, a carrier capable of carrying a test piece, an optical ultrasonic detector, a waveform recorder and a processor. The ultrasonic excitation light source comprises a laser light source and a focusing lens disposed on the optical path of the pulsed light beam for reducing the spot size of the pulsed light beam. The optical ultrasonic detector can detect the surface ultrasonic wave generated by the pulsed laser beam on the test piece, and the waveform recorder can record the surface 101271.doc 1280360 ultrasonic wave, and the processor is based on the ultrasonic wave The surface ultrasonic waves calculate the material properties of the test piece. The optical material property detecting method of the present invention records a supersonic wave on the surface of the test piece by irradiating a pulse beam on a test piece and detecting the pulsed light beam on the surface of the test piece by using interferometry, and recording the surface ultrasonic wave. The material properties of the test piece were calculated based on the surface super-chopper. Calculating the material properties of the test piece based on the surface ultrasonic wave comprises constructing an experimental dispersion curve and calculating the material properties of the test piece based on the experimental dispersion curve and the surface ultrasonic wave. The construction method of the experimental dispersion curve can adopt the phase spectrum method, and the experimental dispersion curve can adopt the material property positive algorithm, and the material property of the test piece can be calculated by the curve fitting method. [Embodiment] 囷1 and Fig. 2 illustrate an optical material property detecting device 1 of the present invention. The optical material property detecting device 10 includes an ultrasonic excitation light source 20 that generates a pulsed beam 22, a stage 30 that can carry a test strip 32, an optical ultrasonic detector 40, and a waveform recorder 62. And a processor 64. The ultrasonic excitation source 20 is a pulsed laser source (e.g., Nd_YAG or Ti-Saphire) and the pulsed beam 22 is a pulsed laser beam having a pulse width of less than 100 nanoseconds. Preferably, the ultrasonic excitation light source 20 includes a laser light source 24 and a focusing lens 28 disposed on the optical path of the pulsed light beam 22 for reducing the spot size of the pulsed light beam 22. The stage 30 is a mobile stage that can change the position of the pulsed beam 22 to illuminate the test piece 32. The optical ultrasonic detector 40 illustrated in Fig. 2 is a Mirau dry 101271.doc
1280360 涉儀，其包含一可發出一雷射光束44之雷射光源42、一設 置於該雷射光源42與該載台30間之Mirau顯微物鏡50以及 一設置於該雷射光束44之反射光路上的反射鏡46及光偵測 器48。該Mirau顯微物鏡50包含一設置於雷射光源42與該載 台30間之透鏡52、一設置於該透鏡52與該載台30間之參考 面鏡54以及一設置於該參考面鏡54與該載台30間之分光鏡 56。該分光鏡56將該雷射光束44分成一參考光58A及一物光 5 8B，該參考光58A及該物光58B分別經由該參考面鏡54及 該試片32反射後重疊而產生一干涉光60。此外，該光學式 超音波偵測器40亦可採用林尼克（Linnik)干涉儀或邁克生 (Michelson)干涉儀架構。 當該脈衝光束22照射於該試片32時，瞬間加熱該試片32 表面，在該試片32表面產生熱彈性應力（thermoelastie stress)，引起熱彈性應變（thermoelastic strain)，表面變形 以波的形式在該試片32表面傳遞形成表面超音波 36(surface acoustic wave，SAW)。該光學式超音波 貞測器 40可偵測該脈衝光束22照射於該試片32所產生之表面超音 波3 6 ’该波形記錄6 2可記錄該表面超音波3 6，而該處理 器64根據該表面超音波36計算該試片32之材料性質。 該表面超音波36之訊號與該光偵測器48量測光強⑴之關 係如公式（1): / /0 cos 4π τ {L2-L}+S0cos(27ft))1280360 is involved in a laser light source 42 that emits a laser beam 44, a Mirau microscope objective 50 disposed between the laser source 42 and the stage 30, and a laser beam 44 disposed thereon. The mirror 46 and the photodetector 48 are reflected on the optical path. The Mirau microscope objective 50 includes a lens 52 disposed between the laser source 42 and the stage 30, a reference mirror 54 disposed between the lens 52 and the stage 30, and a reference mirror 54 disposed therebetween. A beam splitter 56 is placed between the stage 30 and the stage 30. The beam splitter 56 divides the laser beam 44 into a reference light 58A and an object light 5 8B. The reference light 58A and the object light 58B are respectively reflected by the reference mirror 54 and the test strip 32 and overlap to generate an interference. Light 60. In addition, the optical ultrasonic detector 40 can also be constructed using a Linnik interferometer or a Michelson interferometer architecture. When the pulsed light beam 22 is irradiated onto the test piece 32, the surface of the test piece 32 is instantaneously heated, and thermoelastie stress is generated on the surface of the test piece 32, causing thermoelastic strain, and the surface is deformed by waves. The form is transmitted on the surface of the test piece 32 to form a surface acoustic wave (SAW). The optical ultrasonic detector 40 can detect the surface ultrasonic wave generated by the pulsed light beam 22 on the test strip 32. The waveform record 6 2 can record the surface ultrasonic wave 3 and the processor 64 The material properties of the test piece 32 are calculated based on the surface ultrasonic wave 36. The relationship between the signal of the surface ultrasonic wave 36 and the measured light intensity (1) of the photodetector 48 is as shown in the formula (1): / /0 cos 4π τ {L2-L}+S0cos(27ft))
其中’ /。為入射光（即雷射光束44)之強度，厶為該透鏡52 10127l.doc 10 1280360 到该分光鏡56的距離，4為該分光鏡56到該試片32的距 離’ A為該表面超音波36之振福，/為該表面超音波36之頻 率’ ί為時間。由於相位鑑別的需要，必須做至少兩次以上 的激發’且不同的激發點之間必須相隔一段已知距離，亦 即至少需將該脈衝光束22打在該試片32表面之不同位置兩 次。另外’為了使量測不受外界振動的干擾，該載台32較 佳地具有隔振機制。 > 圖3及圖4例示該光學式材料性質檢測裝置10之處理器64 之演算流程。該波形記錄器62記錄由該光偵測器48測得之 表面超音波36。該波形記錄器62可以是示波器、電腦、類 比數位轉換器、資料記錄器（datal〇gger)或其他任何可記錄 電訊號波形的資料記錄裝置。該波形記錄器62記錄之超音 波時域訊號傳送至該處理器64時，該處理器64先以相位頻 譜法將兩次激發的超音波時域訊號轉換成超音波之波速對 頻率的關係圖。相位頻譜法的原理是當該脈衝光束22在該 | 試片32上的聚焦位置與光學干涉儀（即該光學式超音波偵 測器40)偵測點之間的距離改變時，光學干涉儀將會偵測到 不同的波傳行為。假設兩次偵測的距離分別為xl與Χ2，光 學干涉儀彳貞測到的表面波之波形經由傅立葉（Fourier transform)轉換（即圖4中之FFT函數轉換）而得到其相位頻 譜為表(/)與么(/)，/為表面超音波的頻率。導波相速度γ與 頻率之間的關係如下公式（2)(即實驗頻散曲線）：among them' /. For the intensity of the incident light (ie, the laser beam 44), 厶 is the distance from the lens 52 10127l.doc 10 1280360 to the beam splitter 56, 4 is the distance from the beam splitter 56 to the test strip 32 'A is the surface super The vibration of the sound wave 36, / for the frequency of the surface ultrasonic wave 36 'ί is the time. Due to the need for phase discrimination, at least two or more excitations must be performed' and different excitation points must be separated by a known distance, that is, at least the pulsed beam 22 must be placed at different positions on the surface of the test strip 32 twice. . Further, in order to prevent the measurement from being disturbed by external vibration, the stage 32 preferably has a vibration isolation mechanism. > Figs. 3 and 4 illustrate the calculation flow of the processor 64 of the optical material property detecting apparatus 10. The waveform recorder 62 records the surface ultrasonic wave 36 measured by the photodetector 48. The waveform recorder 62 can be an oscilloscope, a computer, an analog digital converter, a data logger (data 〇gger) or any other data recording device that can record electrical signal waveforms. When the ultrasonic time domain signal recorded by the waveform recorder 62 is transmitted to the processor 64, the processor 64 first converts the twice-excited ultrasonic time domain signal into a supersonic wave velocity versus frequency relationship by a phase spectrum method. . The principle of the phase spectrum method is that when the distance between the focus position of the pulse beam 22 on the | test strip 32 and the detection point of the optical interferometer (ie, the optical ultrasonic detector 40) is changed, the optical interferometer Different wave transmission behaviors will be detected. Assuming that the distances of the two detections are x1 and Χ2, respectively, the waveform of the surface wave measured by the optical interferometer is converted into a phase spectrum by a Fourier transform (ie, the FFT function conversion in FIG. 4). /) with (/), / is the frequency of the surface ultrasonic. The relationship between the guided wave phase velocity γ and the frequency is as follows (2) (ie, the experimental dispersion curve):
Vm __ (χ2 101271.doc -11 - 1280360 試片之理論頻散曲線係以材料性質正算法求得。首先是 彈性力學理論中的應力與應變關係本構方程式如公式（3): σν = Cijkl6kl ί，Μ，/ = 1，2,3 =m (3) 其中，Ε為楊氏模數。 應變張量與位移場的關係如下公式（4): 〜=(wu +Ά2 ⑷ 其中％為應力分量，為材料係數、^為應變分量、位 > 移場為K、&為應變張量。 以上述兩式為基礎再考慮材料的特性（例如等向性）並忽 略徹體力（body forces)即可得平衡方程式（equilibrium • equation)如公式（5): °V，y - β發=〇 (5) 其中p為試片之質量密度。當一時諧（time harmonic)且角 頻率似之板波在平板材料中傳遞時，其位移場之各分量可 ® 以表示如公式（6): u. = /=ι，2,3 (6) 其中6、矣為A、A方向上之波數（wave number)，4為位 移偏振分量。（=似7、A =⑽1、矣=⑽2、A = C0S(W/c、\ sin(6〇/c， A、\為slowness components，此處相速度波傳方向0設為 已知，相速度c為待定數值，將公式（4)及（6)代入公式（5)， 並定義％ =ς/ρ以簡化符號，可獲得克里斯多夫方程式 (Christoffel equation)如公式（7)。相關的&定義請如公式 αι)。 I01271.doc -12·Vm __ (χ2 101271.doc -11 - 1280360 The theoretical dispersion curve of the test piece is obtained by the material property positive algorithm. The first is the relationship between stress and strain in the theory of elastic mechanics. The constitutive equation is given by equation (3): σν = Cijkl6kl ί,Μ, / = 1,2,3 =m (3) where Ε is the Young's modulus. The relationship between the strain tensor and the displacement field is as follows (4): ~=(wu +Ά2 (4) where % is the stress Component, material coefficient, ^ is the strain component, bit > The field is K, & is the strain tensor. Based on the above two formulas, consider the properties of the material (such as isotropic) and ignore the body forces. The equilibrium equation can be obtained as in equation (5): °V, y - β = 〇(5) where p is the mass density of the test piece. When time harmonic and angular frequency appear When the plate wave is transmitted in the flat material, the components of the displacement field can be represented by the formula (6): u. = /=ι,2,3 (6) where 6, 矣 is the wave in the A and A directions Wave number, 4 is the displacement polarization component. (= 7, A = (10) 1, 矣 = (10) 2, A = C0S (W / c, \ sin (6 〇 / c, A, \ for slowness components Here, the phase velocity wave direction 0 is set to be known, the phase velocity c is a to-be-determined value, the formulas (4) and (6) are substituted into the formula (5), and %=ς/ρ is defined to simplify the symbol, and the gram can be obtained. The Christoffel equation is given by equation (7). The relevant & definition is given by the formula αι). I01271.doc -12·
零 為 須 必ΓηΓ22 值 式ΙΓΠ1Γ, 列 3 3 Γ1 Γ2 1280360 X r r Ί 丄 12 χ 13 Α； Γ21 Γ Γ 丄22 丄23 <α2 > =0 ⑺ J31 Γ Γ Χ 32 Χ 33 J Λ, Γπ = ：αΐΑ2 + α66^2 + α$$ζ2 ~ 0)2 Γ22 = ^j'+an f+ C2,2 Γ33 = Ζ^2+α44 + ^33^2 ^ 0)2 (7.1) Γ12 = -Γ21 = (“12 + α66Χ<^2 Γ13 = :Γ31=Κ+α55)« Γ23 = ：Γ32 = (α23 + 由於4、Λ、Λ必須有非零解，所以公式（7)中的矩陣行 因此公式（7)為一廣義的特徵值問題。 ⑻ 將公式（8)展開成一組由；72所組成之三次特徵方程式，如 公式（9): Αη6 + €η2 + D-0 ^ = ^55^44^33 B — dssQ^{cissSx + ciA4S2 ^1)+^55^33(^66^ +ct22S2 — l) + a33a44(auS^ + a66S22 -l)-a44(au + a55)2S' -^55(a23 + a44)2 C = a55 (a66S^ + a22Sl2 - l\a55S^ + auS22 -1) + α44(αη^2 +a66S22 - \\as$S2x +aAAS22 -l) + 2(a23 + a44 )(a}3 + a55 )(an + a66 )S^S22 + ^?33 iaUS\ +a66S2 ^^Xa66Sl +anS22-l) ^ ia66Sl + a22St ^ lXa!3 + a55 Ϊ Sl -{anS2x +a66S22 -l){a23+a44)2S22 -a33(au +a66)2S^S22 D = + a66^l ~ !Xa66^12 + a22^l ~ + ^44^2 ~ -a33 (al2 + a66 )2 (a55S^ + auS22 -1) ⑼ 72等於v〆其中vp為導波相速度理論值。解公式（9)之T；2值 101271.doc -13 - 1280360 即可求得理論頻散曲線，如圖5所示。 材料性質處理器的第二個步驟是將所得之實驗頻散曲線 與理論頻散曲線做擬合。將實驗頻散曲線與理論頻散曲線 的誤差平方設為目標函數（SSR)，利用簡單體法找 尋目標函數的最小值將可反算材料常數。定義目標函數為 相速度實驗值與理論值之最小平方差之和。由相速度量測Zero is required ΓηΓ22 value ΙΓΠ1Γ, column 3 3 Γ1 Γ2 1280360 X rr 丄 丄12 χ 13 Α; Γ21 Γ Γ 丄22 丄23 <α2 > =0 (7) J31 Γ Χ Χ 32 Χ 33 J Λ, Γπ = :αΐΑ2 + α66^2 + α$$ζ2 ~ 0)2 Γ22 = ^j'+an f+ C2,2 Γ33 = Ζ^2+α44 + ^33^2 ^ 0)2 (7.1) Γ12 = -Γ21 = ("12 + α66Χ<^2 Γ13 = :Γ31=Κ+α55)« Γ23 = :Γ32 = (α23 + Since 4, Λ, Λ must have a non-zero solution, the matrix line in equation (7) is therefore a formula (7) is a generalized eigenvalue problem. (8) The formula (8) is expanded into a set of three characteristic equations consisting of 72, such as the formula (9): Αη6 + €η2 + D-0 ^ = ^55^44 ^33 B — dssQ^{cissSx + ciA4S2 ^1)+^55^33(^66^ +ct22S2 — l) + a33a44(auS^ + a66S22 -l)-a44(au + a55)2S' -^55( A23 + a44)2 C = a55 (a66S^ + a22Sl2 - l\a55S^ + auS22 -1) + α44(αη^2 +a66S22 - \\as$S2x +aAAS22 -l) + 2(a23 + a44 )( a}3 + a55 )(an + a66 )S^S22 + ^?33 iaUS\ +a66S2 ^^Xa66Sl +anS22-l) ^ ia66Sl + a22St ^ lXa!3 + a55 Ϊ Sl -{anS2x +a66S22 -l) {a23+a44)2S22 -a33(au +a66)2S^S 22 D = + a66^l ~ !Xa66^12 + a22^l ~ + ^44^2 ~ -a33 (al2 + a66 )2 (a55S^ + auS22 -1) (9) 72 is equal to v〆 where vp is the guided wave phase The theoretical value of the velocity. Solve the formula (9) T; 2 value 101271.doc -13 - 1280360 to obtain the theoretical dispersion curve, as shown in Figure 5. The second step of the material property processor is to get the experimental The dispersion curve is fitted with the theoretical dispersion curve. The error square of the experimental dispersion curve and the theoretical dispersion curve is set as the objective function (SSR), and the minimum value of the objective function can be found by the simple body method to calculate the material constant. The objective function is defined as the sum of the least squared difference between the phase velocity experimental value and the theoretical value. Phase velocity measurement
值與相速度理論值所建立的目標函數中，反算出試片的材 料性質。目標函數表示如（1〇)式： SSR^l\(v ) -(vm)]2 tt[Kp)j {p)jl (10) 其中，v〃為導波相速度理論值，v;為導波相速度量測值 值，Μ為輸入實驗群速度值資料之數目。反算的程序通常 都是由一組初始猜測值開始，經由搜尋法則找到另_個較 小目標函數值的鄰近解，接著再以此鄰近解為起始解，重 複地進行迭代，直到沒有比當前目標函數值更小的鄰近解 為止。最後可得到滿足最小目標函數值的材料性質，即ssr 的值為最小時，可以找到滿足誤差平方和極小值的材料係 數’如圖6所示。 本發明之技術内容及技術特點已揭示如上，然而熟悉本 項技術之人士仍可能基於本發明之教示及揭示而作種種不 彦離本發明精神之替換及修飾。因此，本發明之保護範圍 應不限於實施例所揭示者，而應包括各種不背離本發明之 替換及修飾，並為以下之申請專利範圍所涵蓋。 【圖式簡單說明】 圖1及圖2例示本發明之光學式材料性質檢測裝置； 101271.doc -14- 1280360 圖3及圖4例示該光學式材料 咕 負檢測裝置之處理器的演 算流程； 圖5例示本發明計算之理論頻散曲線；以及 圖6例示實驗頻散曲線與理論頻散曲線之擬合結果。 【主要元件符號說明】 10光學式材料性質檢測裝置 20超音波激發光源 2 2脈衝光束 24雷射光源 28聚焦透鏡 30載台 32試片 3 6表面超音波 40光學式超音波偵測器 42雷射光源 44雷射光束 46反射鏡 48反射鏡 50 Mirau顯微物鏡 52透鏡 54參考面鏡 56分光鏡 58A參考光 58B物光 60干涉光 62波形記錄器 64處理器 101271.doc 15-In the objective function established by the value and the theoretical value of the phase velocity, the material properties of the test piece are inversely calculated. The objective function is expressed as (1〇): SSR^l\(v) -(vm)]2 tt[Kp)j {p)jl (10) where v〃 is the theoretical value of the guided wave phase velocity, v; The measured value of the guided wave phase velocity is 数目, which is the number of data of the velocity value of the input experimental group. The inverse calculation program usually starts with a set of initial guess values, finds the adjacent solution of another smaller objective function value via the search rule, and then repeats the iterative solution with the adjacent solution as the starting solution until there is no comparison. The current objective function value is smaller than the adjacent solution. Finally, the material properties satisfying the minimum objective function value can be obtained. When the value of ssr is the smallest, the material coefficient satisfying the square of the error and the minimum value can be found as shown in Fig. 6. The technical contents and technical features of the present invention have been disclosed as above, but those skilled in the art can still make various substitutions and modifications of the present invention based on the teachings and disclosures of the present invention. Therefore, the scope of the present invention should be construed as being limited by the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 illustrate an optical material property detecting apparatus of the present invention; 101271.doc -14- 1280360 FIG. 3 and FIG. 4 illustrate a calculation flow of a processor of the optical material negative detecting device; Figure 5 illustrates the theoretical dispersion curve calculated by the present invention; and Figure 6 illustrates the fitting results of the experimental dispersion curve and the theoretical dispersion curve. [Main component symbol description] 10 optical material property detecting device 20 ultrasonic excitation light source 2 2 pulse beam 24 laser light source 28 focusing lens 30 stage 32 test piece 3 6 surface ultrasonic 40 optical ultrasonic detector 42 Ray Light source 44 Laser beam 46 Mirror 48 Mirror 50 Mirau microscope lens 52 lens 54 reference mirror 56 beam splitter 58A reference light 58B object light 60 interference light 62 waveform recorder 64 processor 101271.doc 15-