1239389 玖、發明說明： 【發明所屬之技術領域】 本發明係有關-種測量折射率之儀器，制是關於一種利用 垂直入射旋光外差干涉技術測量待測物之折射率的垂直入射型折 射率測量裝置。 【先前技術】 折射率的在光學咐、生物f學及化學工㈣佔有相當 =的地位’例如，單純賴種__與混合液體成分的分析: =旦液财度之測定；生物體的體液分析，都可以藉由折射率 ‘ΓΓ成。而為了滿紅業界界快速測量和高射性 t非破壞性、雜觸性及即時測量的純變得更加的重要。 的方用干涉儀測量物體折射率 觸式或是=這財法魏好的解财，但這射法大都屬於接 因此告在、>je人射式的測量方法。由於屬於接觸式的測量方式， 洗探21:=；"折射率時，常會因為接觸到液體而需要清 時，則會 光源為斜向入· k《碩因摩擦而補。當測試 環境的，到外在 其方敎賴切貝（Α㈣折射率計， (Snell，s何姑中的全反料之臨界肖與斯科定律 aw)而來換算出折射率，操作時必須以望遠鏡或顯 1239389 微鏡蚊纽界角雜置_推算出铜物的折射率。版折射 率計雖然:具有缝小的優點，但是它仍有些雜，例如，由於需 要做臨界角角度的測定，所以折射率的精確度將會受限於尺規的 最小刻度，再者，由於它是測量光強度賴係，很料受到環境 背景光的干擾，所以必須在隔離其他賴、的環境下進行測量，此 外它對光源的敎度要求也㈣提高4了戦受光強度的干 擾，目則有利用測量因待測介質在全反射條件下所引進偏光及 S-偏光間之相位差’進而求出待測物之折射率的方法。由於這些 方法必如斜人射肖人射或是必職足全反射條件，因此在測量 系統中必須精確控制人射歧或是加人—個產生全反射的棱 鏡。然14些因素*但會造成折鱗量測上料便，且待測物 的測量範圍仍會受限於稜鏡的折射率。 因此’為改紅収缺點’树贿麵㈣直入射旋 光外差干涉技制量铜物之折射率_直人射型折射率測量裝 置，使其具有體積小及精確度高之優點。 【發明内容】 本毛月之主要目的係在提供_種垂直入射型折射率測量裝 ^係细錄人射旋光外差干涉技術·待測物之折射率， 此方法屬於完全的非破壞性光學檢測，並具有高歡性、高精確 性及無測量範圍限制等之優點。 ^ 另目的係在提供一種垂直入射型折射率測量裝 置“係利用測1相位的方式來得知待測物之折射率，因此將不 1239389 欠環境背景光的干擾及測試光源的穩定度所影響，故可以克服習 知單純利用斯涅耳方程式及測量光強度變化方式來獲得折射率的 缺點。 本發明之再一目的係在提供一種垂直入射型折射率測量裳 置，其係不需改變入射角也不需要外加造成全反射之探頭，所以 對於待測物的量測顧將不會❹賴射率的關，故量測範 圍將較習知方法來的廣泛；且因不f改變人射肖，因此也較一般 量測方法簡單且易於校正光路。 為達到上述之目的，本發明係將一旋光外差光源射出之光線 經一偏光保持光纖之傳導後入射至一最重要的測試模組，其係由 一分光鏡、-四分之-波片、—高反鱗面鏡、—檢偏板及一偵 測器所組成者；當旋光外差光源入射此一模組時，先被分光鏡分 成反射光及透射光兩部分；反射光穿過四分之一波片並經由高反 射率面鏡反射再次通過四分之—波片及分級：透射光的部分則 直接穿透分光鏡入射至待測物，且分光鏡並不與待測物接觸。這 兩道光最後會經分光鏡合併成-絲輯過檢偏板並由偵測器所 接收。接收到的測試訊號將傳送至一相位計中，並與相位計中的 參考訊號比較後便可得到由待測物引進的相位差大小。最後，將 相位計測出_位差代人域斯計算法UQnes ealeulus)與斯 涅耳方程式（Fresnel’ s Equation)所推演的公式中，並由一單 晶片計算出待測物的折射率，最後以數位顯示器顯示出來，以方 7 1239389 便讀取。 底下藉由具體實施触合卿_式詳加朗，當更容易瞭 解本發明之目的、技術内容、獅及其輯成之功效。'、 【實施方式】 本發明係提出-麵直人翻之折射率測錄置，其係將待 測物的反射率直㈣換成干涉訊號_位差，且精麵被外差干 涉術所測量，並根據所測得的相位差值計算求出待測物折射率。 本方法係屬於完全的非破壞性鮮檢測，朗時具有高穩定性、 高精確性及無測量範圍限制等之優點。 第一圖為本發明之結構示意圖，如圖所示，首先，一旋光外 差光源（circularly polarized heterodyne light source) 10， 亦即為左疑偏光與右旋偏光間有角頻差⑺的雷射光源，其所射出 之旋光外差光線經一耦合透鏡（coupling lens) 12導入一偏光保 持光纖（polarization maintaining fiber) 14 中傳導，再經由 準直透鏡（collimating lens) 16將光線準直並射入一測試模 組18中。接著，光線會經由一分光鏡181將此旋光外差光線分成 穿透光（路徑1)及反射光（路徑2)兩部分；該穿透光係垂直入 射至一待測物20，經由待測物20反射之後，再經過分光鏡 (beam-splitter) 181反射並穿透一個與水平軸夾α角的檢偏板 (analyzer) 184後進入一光偵測器185中，其振幅可表示為 (1)， 1239389 (rcos a)e cos—-(rsinacosa)e 2 sin— 2 2 (rsinacosa)e 2 cos—~(rsin2a)e 2 sin— 2 2 其中’ r代表待測物20的反射係數，根據斯淫耳方程气 (Fresnel’ s Equation)可表示為r = g，且/7為待測物2〇之折 射率；合及咖分別代表分光鏡181及穿透光（路徑1)所引進的相 位差。 另一方面，反射光通過一個快軸與水平軸夾45度（方位角固 定在45度）的四分之一波片（quarter wave plate) 182之後入 射至高反射率面鏡183,使用四分之一波片182之目的是為了使旋 光外差光源10的水平分量與垂直分量互換；通過四分之一波片 182之光線再經由一高反射率面鏡（high reflectance mirror) 183反射再次通過四分之一波片182，最後穿過分光鏡181及檢偏 板184之後’進入同一個光偵測器185中，其振幅可表示為： E (-2’rmcos2a)e2rf2)sin(^)+(2/rmsinacosa)e(2‘)cosf (-2zrmsinacosa)e2~2)sinf+(2’rwsin2a)e(2A2)cos(^) 其中’ η代表焉反射率面鏡183的反射係數；知則代表反射光（路 徑2 )所引進的相位差。 因此’經由光偵測器185所測得的測試光強度可表示為：1239389 发明 Description of the invention: [Technical field to which the invention belongs] The present invention relates to a kind of instrument for measuring refractive index, and the system relates to a normal incidence type refractive index for measuring the refractive index of an object to be measured using a normal incidence optical rotation heterodyne interference technique. Measuring device. [Prior art] Refractive index has an equivalent position in optical, biological, and chemical engineering. For example, the analysis of pure liquid species and mixed liquid components: = determination of the financial properties of fluids; body fluids Analysis can be performed by the refractive index 'ΓΓ. In order to fill the red industry, rapid measurement and anti-reflective properties are becoming more important. Fang uses interferometers to measure the refractive index of objects. The touch method or = this good method is a good solution to financial affairs, but most of these shot methods belong to the measurement method of the> je person shooting method. Because it is a contact measurement method, when washing 21: =; " refractive index, it often needs to be cleaned due to contact with liquid, then the light source will enter obliquely. When testing the environment, go to the outside world to calculate the refractive index to Laichebei (Α㈣ refractive index meter, (Snell, s He Gu's all-reverse critical Shaw and Scoll's law aw)), the operation must be The telescope or 1239389 micromirror boundary angle is mixed to calculate the refractive index of the copper object. Although the plate refractive index has the advantages of small slits, it is still a bit complicated, for example, because it is necessary to determine the critical angle Therefore, the accuracy of the refractive index will be limited by the minimum scale of the ruler. Furthermore, because it is a measurement of light intensity, it is expected to be interfered by the ambient background light, so it must be performed in an environment that is isolated from other conditions. In addition to the measurement, it also requires an increase in the intensity of the light source. It is affected by the intensity of light. The purpose is to use the measurement of the phase difference between the polarized light and the S-polarized light introduced under the total reflection condition of the medium to be measured. Methods of the refractive index of the object to be measured. Because these methods must be oblique or radiant, or full-reflection conditions, it is necessary to accurately control human ambiguity or add in the measurement system-one that generates total reflection Prism.Ran 14 Factor *, but it will cause the scale to be measured and loaded easily, and the measurement range of the object to be measured will still be limited by the refractive index of the chirp. Refractive index of copper objects _ direct-injection type refractive index measurement device, which has the advantages of small volume and high accuracy. [Abstract] The main purpose of this month is to provide _ a variety of vertical incidence type refractive index measurement equipment ^ It records the refractive index of the human optical rotation heterodyne interference technique and the refractive index of the object to be measured. This method is a complete non-destructive optical detection, and has the advantages of high delight, high accuracy, and no measurement range limitation. ^ Another The purpose is to provide a normal incidence type refractive index measuring device. "The 1-phase method is used to obtain the refractive index of the object to be measured. Therefore, it will not be affected by the interference of the ambient background light of 1239389 and the stability of the test light source. It overcomes the shortcomings of using the Snell equation and measuring the change of light intensity to obtain the refractive index. Another object of the present invention is to provide a vertical incidence type refractive index measuring device. Need to change the incident angle and do not need to add a probe that causes total reflection, so the measurement of the object to be measured will not depend on the emissivity, so the measurement range will be wider than the conventional method; Change the human shooting angle, so it is simpler and easier to correct the optical path than the general measurement method. In order to achieve the above purpose, the present invention is to transmit the light emitted by a rotating optical heterodyne light source through a polarization-maintaining optical fiber to the most important The test module is composed of a beam splitter, a quarter-wave plate, a high-reflection mirror, an analyzer, and a detector. When the optical rotation heterodyne light source enters this module, First, it is divided into reflected light and transmitted light by the beam splitter; the reflected light passes through the quarter wave plate and is reflected by the high reflectance mirror and then passes through the quarter-wave plate and classification: the transmitted light portion passes directly The transmissive beam splitter is incident on the object to be measured, and the beam splitter is not in contact with the object to be measured. These two lights are finally combined by a beam splitter into a silk-screened analyzer and received by the detector. The received test signal will be sent to a phase meter and compared with the reference signal in the phase meter to obtain the phase difference introduced by the DUT. Finally, the phase meter measures the formula derived from UQnes ealeulus and Fresnel's Equation, and calculates the refractive index of the test object from a single chip. Finally, It is displayed on the digital display, and it can be read by 7 1239389. Through the specific implementation of the contact details, it is easier to understand the purpose, technical content, lion and its compiled effects of the present invention. ', [Embodiment] The present invention proposes-the refractive index measurement and recording of a straight face, which changes the reflectance of the object to be measured into an interference signal_position difference, and the fine surface is measured by heterodyne interferometry. And calculate the refractive index of the object to be measured according to the measured phase difference value. This method is a complete non-destructive fresh detection, and Lange has the advantages of high stability, high accuracy, and no measurement range limitation. The first figure is a schematic diagram of the structure of the present invention. As shown in the figure, first, a circularly polarized heterodyne light source (circularly polarized heterodyne light source) 10, that is, a laser with angular frequency difference between left and right polarized light The light source emits the optically polarized heterodyne light through a coupling lens 12 into a polarization maintaining fiber 14 for transmission, and collimates the light through a collimating lens 16 A test module 18. Then, the light is divided into two parts, the penetrating light (path 1) and the reflected light (path 2) by a beam splitter 181; the penetrating light is incident on a test object 20 perpendicularly and passes through the test object 20 After the object 20 is reflected, it is reflected by a beam-splitter 181 and penetrates an analyzer 184 with an angle α to the horizontal axis, and then enters a light detector 185. Its amplitude can be expressed as ( 1), 1239389 (rcos a) e cos —- (rsinacosa) e 2 sin— 2 2 (rsinacosa) e 2 cos— ~ (rsin2a) e 2 sin— 2 2 where 'r represents the reflection coefficient of the test object 20, According to Fresnel's Equation, it can be expressed as r = g, and / 7 is the refractive index of the object to be measured. The total and representative beams are introduced by the spectroscope 181 and the transmitted light (path 1). Phase difference. On the other hand, the reflected light passes through a quarter-wave plate 182 with a fast axis and a horizontal axis clamped at 45 degrees (azimuth angle is fixed at 45 degrees), and then enters the high-reflection mirror 183. The purpose of a wave plate 182 is to interchange the horizontal component and the vertical component of the optical rotation heterodyne light source 10; the light passing through the quarter wave plate 182 is reflected by a high reflectance mirror 183 and passes through the four again. The half-wave plate 182 finally passes through the beam splitter 181 and the analyzer plate 184 and enters the same light detector 185. Its amplitude can be expressed as: E (-2'rmcos2a) e2rf2) sin (^) + (2 / rmsinacosa) e (2 ') cosf (-2zrmsinacosa) e2 ~ 2) sinf + (2'rwsin2a) e (2A2) cos (^) where' η represents the reflection coefficient of the 焉 reflectance mirror 183; the knowledge represents the reflection coefficient Phase difference introduced by light (path 2). Therefore, the test light intensity measured by the light detector 185 can be expressed as:
It =|^1+^2|2 =/〇[l + rcos(^+^)] (3)， 其中’ /〇、；Κ分別為調制訊號之振幅項與對比度（visibility); 0為 1239389 由待測物20所引進水平偏光及垂直偏光間之相位差，其值可分別 表示為： r_ 4a2+B2 [2+2r- +4(^TT)r- cosasinasin^^ -^2)] ^ = tan'1(—), A 其中，d與方可表示成： 1 ϊϊ — 1Ζ = Ι[(5Γϊ)2 一 4以]· (c〇s2 α -也2 α) (4a)， (4b)， (4c) ^ (5a)， 5=〇2—4 介—蘇 (5b) 因此’根據式（5)所示可將式(4c)改寫成： tan" n-h Ίί + Υ [('—ζΫ ~4r^]cosasina-2(-~-)r n + l m 2^^γ)2 -4rw2](cos2a-sin2a) (6) 此外，可由一相位計（phasemeter) 22產生一同步訊號作為 參考訊號，其形式可表示為： ⑺It = | ^ 1 + ^ 2 | 2 = / 〇 [l + rcos (^ + ^)] (3), where '/ 〇,; κ are the amplitude terms and contrast of the modulation signal, respectively; 0 is 1239389 The phase difference between the horizontally polarized light and the vertically polarized light introduced by the test object 20 can be expressed as: r_ 4a2 + B2 [2 + 2r- +4 (^ TT) r- cosasinasin ^^-^ 2)] ^ = tan'1 (—), A, where d and square can be expressed as: 1 ϊϊ — 1Z = Ι [(5Γϊ) 2-4 to] · (c0s2 α -also 2 α) (4a), (4b ), (4c) ^ (5a), 5 = 〇2—4 介 — 苏 (5b) Therefore, according to formula (5), formula (4c) can be rewritten as: tan " nh Ίί + Υ [('— ζΫ ~ 4r ^] cosasina-2 (-~-) rn + lm 2 ^^ γ) 2 -4rw2] (cos2a-sin2a) (6) In addition, a phasemeter 22 can generate a synchronization signal as a reference signal , Its form can be expressed as: ⑺
Tr =-[l + COS(^)] 因此，將光偵測器185所測得的測試訊號輸入至相位計22中，並 與其所產生的同步參考訊號做計算便可以量得由待測物2〇所引進 之水平偏光及垂直偏光之相位差0。當相位差火則出後再將此值代 1239389 入由瓊斯計算法(】QnesealGulus)及卿里耳株式(F_ei, s Equation)所推演的公式⑹中，由_單晶片24計算出待測物卻 的折射率，最後由—數位顯示H 26顯示出來。 本折射率里測裝置中所設計的測試模、组18 ’其組成包括分光 鏡181、四分之—波片182、高反射率面鏡183、檢偏板184及谓 測益185可構成一個體積小，並可設計成一完全密閉且易於連接 光源及相位計的獨立硬體測試模組。且準直透鏡16可以與測試模 組18完全連接而降低外來環境對測量結果的影響。另外，進入測 試模組18的光線可以直接穿透分光鏡181後，經待測物2〇反射 後由光_器185接收。由光偵測器185所量得的測試訊號可先 时鎖相放大減由單晶#24計算讀將折射率鋪示於數位顯示 器20上在測里日守’測試窗口並不與待測物接觸，因此不會有刮 傷測試元件及制物表_舰；同時，_物可崎時更換而 即時測得其折射率值。 一為了改進先前技狀缺點並且㈣兼具難小、精確度 高的優點，本發明係_垂直人射旋光外差干涉技酬量待測^ ^折射率。由於本_侧關量她的方式，因此將不受環境 背景光的干擾及觀辆的歡度響，故可域服單純利用 斯埋耳方程式及測量光強度變化方式來獲得折射率的缺點。此 外’本發明不需改變入射角也不需要外加造成全反射之探頭，所 以對於待測物的量測範圍將不會受探頭折射率的限制，故量測之 1239389 範圍將較一般的方法來的廣泛；且因不需改變入射角，因此也較 一般量測方法簡單且易於校正光路。而上述可經由測量待測物折 射率而推得的一切物理量，如氣體、液體濃度；液體之酸鹼度； 固體、液體之溫度等，皆可以基於本發明之技術而加以達成。 【圖式簡單說明】Tr =-[l + COS (^)] Therefore, by inputting the test signal measured by the photodetector 185 into the phase meter 22 and calculating with the synchronous reference signal generated by it, the object to be measured can be measured 2 The phase difference between the horizontally polarized and vertically polarized light introduced is 0. When the phase difference is out, replace this value with 1239389 and enter it into the formula ⑹ derived by Jones calculation method (QnesealGulus) and F_ei, s Equation, and calculate the object to be measured from _single chip 24 However, the refractive index is finally displayed by the digital display H 26. The test mode designed in this refractive index measuring device, group 18 ', consists of a spectroscope 181, a quarter-wave plate 182, a high reflectance mirror 183, an analyzer plate 184, and a so-called measurement benefit 185. It is small in size and can be designed as an independent hardware test module that is completely enclosed and easily connected to a light source and a phase meter. In addition, the collimator lens 16 can be fully connected to the test module 18 to reduce the influence of the external environment on the measurement result. In addition, the light entering the test module 18 can directly penetrate the beam splitter 181 and be reflected by the test object 20 and then received by the optical device 185. The test signal measured by the photodetector 185 can be phase-locked, amplified and subtracted in advance. Calculated and read by the single crystal # 24. The refractive index is displayed on the digital display 20. The test window is not related to the test object. Contact, so there will be no scratch test elements and manufacturing table _ ship; At the same time, the _ thing can be replaced at the time and its refractive index value is measured immediately. First, in order to improve the shortcomings of the prior art and have the advantages of being difficult to be small and having high accuracy, the present invention is to measure the refractive index of the vertical human optical rotation heterodyne interference technique. Because this method measures her way, it will not be affected by the ambient background light and the joy of watching cars. Therefore, you can use the Spiegel equation and measure the change in light intensity to obtain the shortcomings of the refractive index. In addition, the present invention does not need to change the incident angle and does not need to add a probe that causes total reflection, so the measurement range of the object to be measured will not be limited by the refractive index of the probe. Therefore, the measurement range of 1239389 will be more general. It has a wide range; and because it does not need to change the angle of incidence, it is simpler than ordinary measurement methods and easy to correct the optical path. All the physical quantities, such as the concentration of gas and liquid, the pH of liquid, and the temperature of solid and liquid, which can be deduced by measuring the refractive index of the test object, can be achieved based on the technology of the present invention. [Schematic description]
以上所述之實施例僅係為說明本發明之技術思想及特點，其 目的在使獅此項技藝之人士㈣瞭解本發明之魄並據以實 施，當不能以之限定本發明之專利範圍，即大凡依本發明所 之精_狀均賴域修飾，健涵蓋在本發明之相範圍内不 第一圖為本發明之結構示意圖Q 圖號說明： 10旋光外差光源 12耦合透鏡 14偏光保持光纖 16準直透鏡 18 測試模組 181分光鏡 182四分之一波片 183高反射率面鏡 184檢偏板 185偵測器 20待測物 12 1239389 22相位計 24單晶片 26數位顯示器The above-mentioned embodiments are only for explaining the technical ideas and characteristics of the present invention, and the purpose thereof is to enable those skilled in the art of lion to understand the spirit of the present invention and implement them accordingly. When the scope of the patent of the present invention cannot be limited, That is to say, the essence of the invention is modified according to the present invention, and it is covered within the scope of the present invention. The first picture is a schematic diagram of the structure of the invention. Q Drawing number description: 10 optical rotation heterodyne light source 12 coupling lens 14 polarization retention Optical fiber 16 Collimation lens 18 Test module 181 Beamsplitter 182 Quarter-wave plate 183 High reflectance mirror 184 Polarizer 185 Detector 20 DUT 12 1239389 22 Phase meter 24 Single chip 26 Digital display