201104277 六、發明說明： -:【發明所屬之技術領域】 本發明係有關於一種時漂校正電路以及時漂校正感測 系統，特別係一種校正長時間量測中所輸出漂移訊號之時 漂校正電路以及時漂校正感測系統。 【先前技術】 近年來由於生活水準提高，環境監測、居家檢測及產業 自動化等領域受到重視，感測器之研究逐漸展開，其中以 生物感測器（Biosensor)而吕，已逐漸被應用於實際之臨 床檢驗’感測器因時漂現象所導致之不穩定現象已不能忽 視。 時漂係於相同溫度條件下，長時間持續量測時，量測 系統之輸出電位會隨著時間漂移，使得感測器之穩定度不 佳，此時漂之現象限制感測元件的應用性.，不適用於高準 確度之環境。 下列為若干相關之專利： 美國專利第4,701，253號，發明者Hendrikus C. G. Ligtenberg 以及 J0zef g. Μ· Leuveld，發證日期： 987/10/20 ’ 專利名稱.isFET-based measuring device and for correcting drift”，其量測系統係由離子感測場效 電曰曰體、參考電極、放大||、控制與校正電路、記憶體、 =與保持電路與微處㈣所構成，勤控健校正電路 %疋離子感測場效電晶體之源極電流及離子感測場效電晶 體的時漂校正，時漂校正係藉由微處理器，^〔乂+1)之 201104277 方程式作時漂補償，其中係電位之時漂，2係時漂之振 福’ f。係時間常數，而？為感.測器運作之時間。此專利發明 有效的校正離子感測場效電晶體之時漂，然而其系統較為 複雜。 美國專利第4,691，167號，發明者Hendrik H. v.d. Vlekkert 以及 Nicolaas F. de Rooy，發證日期：1987/9/1， 專利名稱：“Apparatus for determining the activity of an ion (pion) in a liquid”，此裝置係由量測電路包含離子感測場 # 效電晶體、參考電極、溫度控制器、放大器、控制與計算 電路與記憶體所構成，此控制與計算電路及記憶體係作為 穩定離子感測場效電晶體之參數，包含閘極與源極之偏壓 及源極電流，以偵測離子之活性’藉由溫度控制閘極偏壓 與源極電流之變化，計算記憶體中之數據得知感測器的感 測度。此專利發明之裝置不僅可偵測離子活性，且藉由溫 度補償可計算任何溫度下之離子活性。 美國專利第5,046,028號，發明者Avron I. Bryan以及 • Michael R. Cushman，發證日期：1991/9/3，專利名稱：201104277 VI. Description of the invention: -: [Technical field to which the invention pertains] The present invention relates to a time drift correction circuit and a time drift correction sensing system, in particular to a time drift correction for correcting the output drift signal in a long time measurement Circuit and time drift correction sensing system. [Prior Art] In recent years, due to the improvement of living standards, environmental monitoring, home detection and industrial automation have been paid attention to, and the research of sensors has gradually begun. Among them, Biosensor has been gradually applied to practical applications. The clinical test 'the instability of the sensor caused by the drift phenomenon can not be ignored. The drift is tied to the same temperature condition. When the measurement is continued for a long time, the output potential of the measurement system will drift with time, which makes the stability of the sensor poor. At this time, the drift phenomenon limits the applicability of the sensing component. ., does not apply to high accuracy environments. The following are a number of related patents: US Patent No. 4, 701, 253, inventor Hendrikus CG Ligtenberg and J0zef g. Μ Leuveld, date of issue: 987/10/20 ' patent name. isFET-based measuring device and for correcting drift The measurement system is composed of ion sensing field effect electric body, reference electrode, amplification||, control and correction circuit, memory, = and holding circuit and micro (4), and diligent control correction circuit% The source current of the erbium-ion sensing field-effect transistor and the time-lapse correction of the ion-sensing field-effect transistor, the time-lapse correction is compensated by the time-lapse of the 201104277 equation of the microprocessor, ^[乂+1), wherein The time drift of the potential, the vibration of the 2 series is the time constant, and the time is the operation time of the sensor. This patent invention effectively corrects the time drift of the ion sensing field effect transistor, however The system is more complicated. US Patent No. 4,691,167, inventor Hendrik H. vd Vlekkert and Nicolaas F. de Rooy, date of issue: 1987/9/1, patent name: "Apparatus for determining the activity of an ion (p Ion) in a liquid", the device consists of a measuring circuit comprising an ion sensing field, an effect transistor, a reference electrode, a temperature controller, an amplifier, a control and calculation circuit and a memory, the control and calculation circuit and the memory The system acts as a parameter for stabilizing the ion-sensing field-effect transistor, including the bias and source currents of the gate and the source to detect the activity of the ions' by temperature controlling the change of the gate bias and the source current. The data in the memory is used to determine the sensitivity of the sensor. The device of the invention not only detects the ionic activity, but also calculates the ionic activity at any temperature by temperature compensation. U.S. Patent No. 5,046,028, the inventor Avron I Bryan and • Michael R. Cushman, date of issue: 1991/9/3, patent name:
System for calibrating, monitoring and reporting the status of apH sensor” ’該專利係揭示一系統，運用感測器於線上 (on line)與即時之量測，上述感測器之運作係藉由週期 性的判斷薄膜與溶液之間的特性’此元件置放於固定之容 器内’此固定之容器與溶液的流速無關，且此元件係以非 導體之材質包覆與具回流裝置，允許溶液穩定的流經感測 器薄膜表面。整個系統包含量測電路.、類比數位轉換器、 電腦系統與顯示裝置。此專利發明裝置將感測訊號由電腦 201104277 系統§十鼻已顯示裝置呈現酸驗值，並可用於線上與即時之 量測。_ . · 美國專利苐5,814,280號，發明者Katsuhiko Tomita、System for calibrating, monitoring and reporting the status of apH sensor" 'This patent discloses a system that uses sensors to measure on-line and on-the-fly. The operation of the sensor is determined periodically. The property between the film and the solution 'This component is placed in a fixed container'. This fixed container is independent of the flow rate of the solution, and this component is coated with a non-conductor material and has a reflux device to allow the solution to flow stably. Sensor film surface. The whole system includes measurement circuit, analog digital converter, computer system and display device. The device of the invention invents the sensing signal from the computer 201104277 system § ten nose display device to display the acid value and is available On-line and on-the-fly measurement. _ . · US Patent No. 5,814,280, inventor Katsuhiko Tomita,
Tsuyoshi Nakanishi、Syuji Takamatsu、Satoshi Nomura 以 及Hiroki Tanabe ’發證日期：1998/9/29，專利名稱： “Semiconductor pH sensor and circuit and method of making same”，該專利係揭示一種離子感測場效電晶體，其氧化鋁 薄膜成長於矽基板上’再成長單晶矽於氧化鋁薄膜上，元 件之源極與汲極係由單晶矽備製而成，而酸鹼響應薄膜係 連接源極與汲極，此酸鹼感測器可藉由適當之電路整合於 同一 SOI基板上，並結合微處理器與顯示器，製作成酸鹼 感測器。此專利發明皆使用半導體製程之材料，結合半導 體製程可大量生產化。 美國專利第6,464,940號·，發明者Koji Akioka以及 Akira Sanjoh，發證日期：2002/10/15，專利名稱：“PH sensor and pH measurement method employed the same”。該專利係 揭示一種可量測微量溶液酸鹼值之酸鹼感測器，此感測器 係於氧化層矽基板上製作儲存溶液之空間，溶液於氧化層 上方，並製作一電極與溶液中之氧化層接觸，另一電極製 作於基板月面’錯由電容電麗（Capacitance-Voltage，C-V) 之特性’由平帶電壓（flat-band voltage)之計算，判斷溶 液之酸驗值。此專利發明之特點係可直接量測微量溶液酸 驗值。 美國專利第 6,624,637 號，發明者 Torsten Pechestein， r * 發證日期.2003/9/23，專利名稱：“Device for measuring the 201104277 種量 concentrations in a measuring liquid”。該專利係揭示 測離子濃度之元件，特別係對氫.離子之濃度，於量剛上將 離子感測場效電晶體整合於電子電路内，而此電路之輪出 訊號提供待測液離子濃度的資訊’為了使電路簡單化，此 電路由幾個元件所組成，包含至少一個離子感測場效電曰曰 體’以橋式連接三個電阻’經由判別橋式兩端之電位差， 取得離子響應電位。此專利發明襞置藉由橋式架構之平 衡’排除元件間共模之熱雜訊’運用於溫度補償之量測架Tsuyoshi Nakanishi, Syuji Takamatsu, Satoshi Nomura, and Hiroki Tanabe 'certification date: 1998/9/29, patent name: "Semiconductor pH sensor and circuit and method of making same", which discloses an ion sensing field effect transistor The alumina film is grown on the ruthenium substrate, and the single crystal is grown on the aluminum oxide film. The source and the drain of the device are made of single crystal, and the acid-base responsive film is connected to the source and the ruthenium. The acid-base sensor can be integrated into the same SOI substrate by a suitable circuit, and combined with a microprocessor and a display to form an acid-base sensor. This patented invention uses materials from semiconductor processes and can be mass-produced in conjunction with semi-conducting processes. U.S. Patent No. 6,464,940, inventor Koji Akioka and Akira Sanjoh, date of issue: 2002/10/15, patent name: "PH sensor and pH measurement method employed the same". The patent discloses an acid-base sensor capable of measuring the pH value of a trace solution. The sensor is used to make a space for storing a solution on a substrate of a oxide layer, a solution is above the oxide layer, and an electrode and a solution are prepared. The oxide layer is contacted, and the other electrode is formed on the substrate moon surface. The error is calculated by the flat-band voltage. The acid value of the solution is judged by the calculation of the capacitance of the capacitor (Capacitance-Voltage, CV). The feature of this patented invention is that the acidity of a trace solution can be directly measured. U.S. Patent No. 6,624,637, inventor Torsten Pechestein, r*, date of issuance. 2003/9/23, patent name: "Device for measuring the 201104277 quantity in a measuring liquid". The patent discloses a component for measuring the ion concentration, in particular for the concentration of hydrogen ions, integrating the ion sensing field effect transistor into the electronic circuit on the quantity, and the round signal of the circuit provides the ion concentration of the liquid to be tested. In order to simplify the circuit, this circuit consists of several components, including at least one ion-sensing field-effect electric body, which bridges three resistors, and obtains ions by discriminating the potential difference between the two ends of the bridge. Response potential. This patented invention is applied to the temperature-compensated measuring frame by the bridge architecture balance 'excluding the thermal noise of the common mode between components'
構。 【發明内容】 本發明之一實施例，提供一種時漂校正電路，包括： 一第一儀表放大器，電連接一電壓式酸鹼感測元件，用於 接收來自電壓式酸驗感測元件的一感測訊號以及輸出一第 一訊號；一反向放大器，電訊號連接第一儀表放大器.，用 於接受苐一訊號以及輸出一反向訊號；一第二儀表放大 器，電訊號連接電壓式感測電極，用於接收來自電壓式酸 鹼感測元件的感測訊號以及輸出一第二訊號；一加法電 路’電訊號連接反向放大器以及第二儀表放大器，用於相 加反向訊號與第二訊號以及輸出經過時漂校正的一變應訊 號。 一 ° 本發明之另-實施例，提供-種時漂校正感測系統， 包括：一緩衝溶液·，一溫度控制器；一參考電極，位於緩 衝溶液中，其一端接地，係用以提供一固定電位；一熱電 耦，位於緩衝溶液中，並且連接至溫度控制器；一加熱器， 201104277 用於加熱缓衝溶液，並且連接至溫度控制器；一酸驗感測 元件’位於缓衝溶液中，用於感測緩衝溶液的酸驗度；一 時漂校正電路，連接酸鹼感測裝置，用於校正來自酸驗感 測裝置的一感測訊號，並且輸出經過時漂校正的一響應電 壓；一數位精密電表，連接時漂校正電路’用於測量塑應 電壓；一資料記錄器，連接數位精密電表，用於紀錄響應 電壓；以及一暗箱’用以隔離光線以避免光線影響感測訊 號。 【實施方式】 為使本發明之上述目的、特徵和優點能更明顯易 懂，下文特舉較佳實施例，並配合所附圖式，作詳細說 明如下： 請參閱第1圖，依據本發明實施例說明時漂校正電路 之結構。時漂校正電路1 〇〇係一第一儀表放大器101、一 第二儀表放大器102、一反相放大器103以及一加法器104 所構成。 第一及第二儀表放大器101及102，例如商用儀表放 大器AD620,用於擷取前端一電壓式酸鹼感測元件（未顯示) 所感測之電位訊號，第一儀表放大器1〇1將輸出傳送至反 相放大器103，此反向放大器1〇3可調整負迴授電阻尺2來 決定輸出電壓為多少比例之輸入電壓.，而電阻r3是用來降 低偏壓電流所造成之誤差。反向放大器之輸出為反向訊號 — △Ve以一加法器104將反向訊號一Δν與第二儀表放大 器102所輸出之訊號相加，·可得校正後之響應電壓。 201104277 請參閱第2圖，依據本發明之實施例說明一時漂校正 感測系統。時漂校正電路感測系統200包括前道的時漂校 正電路100 ’ 一電壓式酸鹼感測元件201，一數位精密電表 202，一資料記錄器203，>參考電極204，一熱電耦205， 一比例積分微分（“proportional integral derivative” PID)溫 度控制器206，一加熱器裝置207，一緩衝溶液209以及一 暗箱208。暗箱208用於容納電壓式酸鹼感測元件201、參 考電極204、熱電耦205、加熱器裝置207以及緩衝溶液 • 209。 熱電耦205以及加熱器裝置207連接到PID溫度控器 器.206。PID溫度控制器206依據熱電耦205所感應到的電 壓來控制其加熱器裝置207，藉此調整缓衝溶液209於固 定溫度，於本實施例中，PID溫度控制器將溫度控制在大 約27度。時漂校正電路100則連接電壓式酸鹼感測元件 .201以及數位精密電表202。時漂校正電路1〇〇接收電壓式 酸鹼感測元件201的感測訊號，經過校正之後輸出響應電 • 壓，由數位精密電表.202測量輸.出響應電壓.然後傳送到 數位精密電表.202所連接的資料記錄器2〇3,將響應電壓 逐一紀錄。其中數位精密電表2〇2係型號為0八^以加 ΗΡ344〇1Α之數位電表，或是其他可用來量測之類似的儀 器，參考電極則包括銀/氣化銀電極。 請參閱第3圖，依據本發明之實施例說明一種二氧化 釕酸鹼感測元件。感測元件300包含一基板3〇卜=質可 為玻璃。此外’可使用陶究基板或石夕基板來取代破璃美板。 -感測薄臈302沉積於基板3〇1上’其可為二氧土化訂 201104277 (Ruthenium Dioxide，RU〇2)薄膜，係利用半導體製程技 術之射頻麟法成長於基板3()1之上。絕緣層3()3包覆於 上述二氧化釕/玻璃基板結構之周圍部份，用於固定、絕 緣以及支持之用，並且使得上述未包覆絕緣層撕之感測 器部份可與制溶液制，⑽行相。絕緣層之材料係 樹月^複合物、環氧物、石夕膠（silieGne) 1橡膠（仙_ ΓΓ Λ樹脂，彈性pu、多孔PU、丙稀酸橡膠、藍膠、 UV膠、塑膠、環氧樹脂、防水膠其中之一。 ί 發Γ之實施例’使用—酸㈣測^量測酸驗值 θ不。，配第2圖所示之時漂校正電路感測系統， 於酉义驗值7的緩衝溶液巾量取本質響應（快響應與慢響應 、、σ束後之第5小時開始至第u小時之穩定電壓以計算時漂 率’可得知校正前之時漂率為3167毫伏/小時。 " 於理想模型中，對於峻驗值7的緩衝液，其 結束後之第5小時至第12切^，其時漂率如第5圖】 線所示，接近G亳伏/小時。實務上，校正後賴型最好是 接近理想的模型，如第5圖實線所示。 根據本發明的另一實施例，第6圖為-酸驗感測与於 酸驗值為7之緩衝溶液内12小時的響應電壓與量測時間之 關係圖纟中原始時漂訊號在經過校正電路以—— 5%>^校正之後(調整R2)，可得時漂率為ι ι〇 時 ( mV/h)。 ^ J ^ 依據本發明之另一實施例，酸驗感測器的酸驗值於3 5、7、9時之酸驗響應如第7圖所示。結果顯示本發明之 201104277 系統對於酸鹼之感測度為38.968毫伏/酸鹼值（mV/pH)， ，線性度-為0.997。 . 根據本發明的另一實施例，第8圖為一酸鹼感測器於 酸鹼值7時之緩衝溶液内12小時之響應電壓與量測時間之 關係圖。其中原始時漂訊號在經過校正電路以一AV = — 正之後，可得知時漂率為0.268毫伏/小時 (mV/h)。 依據本發明之另一實施例，酸鹼感測器酸鹼值介於3、 • 5、7、9時之酸鹼響應如第9圖所示。結果顯示本發明之 系統對於酸驗之感測度為10.469毫伏/酸驗值（mV/pH)， 線性度為0.988。 最後，熟此技藝者可體認到他們可以輕易地使用揭露 的觀念以及特定實施例為基礎而變更及設計可以實施同樣 目的之其他結構且不脫離本發明以及申請專利範圍。 201104277 【圖式簡單說明】 第1圖係依據本發明之實施例說明時漂校正電-路之架 構； 第2圖係依據本發明之實施例說明時漂校正感測系統 之架構； 第3圖係依據本發明之實施例說明二氧化釕酸鹼感測 元件之架構； 第4圖係顯示酸鹼值7的緩衝溶液之實際時漂曲線圖； 第5圖係顯示酸鹼值7的缓衝溶液之理想時漂曲線圖 · 以及校正時漂曲線圖； 第6圖根據本發明實施例係顯示經過校正之酸鹼值7 的缓衝溶液之時漂曲線圖； 第7圖係顯示經過校正之感測度與線性度的示意圖； 第8圖根據本發明的另一實施例係顯示經過校正之酸 鹼值7的緩衝溶液之時漂曲線圖；以及 第9圖係顯示經過校正之感測度與線性度的示意圖。 【主要元件符號說明】 100〜時漂校正電路； 101〜第一儀表放大器； 102〜第二儀表放大器； 103〜反向放大器 104〜加法器； 200〜時漂校正感測系統； · 12 201104277 201〜電壓式酸鹼感測元件； 202〜數位精密電表； 203〜資料記錄器； 204〜參考電極； 205〜熱電耦； 206〜PID溫度控制器； 207〜加熱器裝置； 208〜暗箱； • 2〇9〜缓衝溶液； 301〜基板； 302〜感測薄膜； 303〜絕緣層。Structure. SUMMARY OF THE INVENTION An embodiment of the present invention provides a time drift correction circuit, including: a first instrumentation amplifier electrically connected to a voltage acid-base sensing component for receiving a voltage sensing component from a voltage type Sense signal and output a first signal; an inverting amplifier, the electrical signal is connected to the first instrumentation amplifier, for receiving the first signal and outputting a reverse signal; and a second instrumentation amplifier, the electrical signal is connected to the voltage sensing An electrode for receiving a sensing signal from the voltage acid-base sensing element and outputting a second signal; an adding circuit 'electric signal connecting the inverting amplifier and the second instrumentation amplifier for adding the reverse signal and the second The signal and the output signal of the output after the drift correction. A further embodiment of the present invention provides a time-lapse correction sensing system comprising: a buffer solution, a temperature controller; a reference electrode, located in the buffer solution, one end of which is grounded to provide a a fixed potential; a thermocouple located in the buffer solution and connected to the temperature controller; a heater, 201104277 for heating the buffer solution, and connected to the temperature controller; an acid sensing element 'located in the buffer solution For sensing the acidity of the buffer solution; the first-time drift correction circuit is connected to the acid-base sensing device for correcting a sensing signal from the acid sensing device, and outputting a response voltage that is corrected by the time drift; A digital precision meter, connected to the drift correction circuit 'for measuring the plastic voltage; a data logger, connected to a digital precision meter for recording the response voltage; and a black box 'to isolate the light to avoid the light affecting the sensing signal. The above described objects, features, and advantages of the present invention will become more apparent from the aspects of the preferred embodiments of the invention. The embodiment illustrates the structure of the time drift correction circuit. The time drift correction circuit 1 is composed of a first instrumentation amplifier 101, a second instrumentation amplifier 102, an inverting amplifier 103, and an adder 104. The first and second instrumentation amplifiers 101 and 102, such as the commercial instrumentation amplifier AD620, are used to capture the potential signal sensed by a voltage-type acid-base sensing element (not shown) at the front end, and the first instrumentation amplifier 1〇1 outputs the output. To the inverting amplifier 103, the inverting amplifier 1〇3 can adjust the negative feedback resistor 2 to determine the ratio of the input voltage to the input voltage, and the resistor r3 is used to reduce the error caused by the bias current. The output of the inverting amplifier is a reverse signal - ΔVe is added by an adder 104 to the signal output from the second meter amplifier 102 by the reverse signal Δν, and the corrected response voltage is obtained. 201104277 Referring to Figure 2, a one-time drift correction sensing system is illustrated in accordance with an embodiment of the present invention. The time drift correction circuit sensing system 200 includes a front time drift correction circuit 100'. A voltage type acid-base sensing element 201, a digital precision electric meter 202, a data recorder 203, a reference electrode 204, and a thermocouple 205. , a proportional integral derivative (PID) temperature controller 206, a heater device 207, a buffer solution 209, and a black box 208. The black box 208 is for housing the voltage acid-base sensing element 201, the reference electrode 204, the thermocouple 205, the heater device 207, and the buffer solution 209. Thermocouple 205 and heater unit 207 are coupled to PID temperature controller .206. The PID temperature controller 206 controls its heater device 207 according to the voltage sensed by the thermocouple 205, thereby adjusting the buffer solution 209 at a fixed temperature. In this embodiment, the PID temperature controller controls the temperature at approximately 27 degrees. . The time drift correction circuit 100 is connected to a voltage type acid-base sensing element .201 and a digital precision meter 202. The time drift correction circuit 1 receives the sensing signal of the voltage acid-base sensing element 201, and after being corrected, outputs a response voltage and voltage, and the digital precision meter. 202 measures the output voltage and then transmits it to the digital precision meter. The data logger 2〇3 connected to 202 records the response voltage one by one. Among them, the digital precision meter 2〇2 series is a digital meter with a number of 八8ΗΡ1Α, or other similar instruments that can be used for measurement, and the reference electrode includes a silver/vaporized silver electrode. Referring to Figure 3, a bismuth citrate sensing element is illustrated in accordance with an embodiment of the present invention. The sensing component 300 includes a substrate 3 and may be glass. In addition, the ceramic substrate or the stone substrate can be used instead of the broken glass. The sensing thin layer 302 is deposited on the substrate 3〇1, which can be a Ruthenium Dioxide (RU〇2) film, which is grown on the substrate 3 by using the RF process of the semiconductor process technology. on. The insulating layer 3 () 3 is coated on the peripheral portion of the above-mentioned ceria/glass substrate structure for fixing, insulating and supporting, and the sensor portion of the uncoated insulating layer can be made Solution solution, (10) line phase. The material of the insulating layer is sapwood compound, epoxy, silieGne 1 rubber (sin _ ΓΓ Λ resin, elastic pu, porous PU, acrylic rubber, blue rubber, UV glue, plastic, ring One of the oxygen resin and the waterproof rubber. ί Γ Γ 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施 实施The buffer solution of value 7 takes the essential response (fast response and slow response, stable voltage from the 5th hour to the u-th hour after the σ beam to calculate the drift rate), and the drift rate before correction is 3167. Millivolts/hour. " In the ideal model, for the buffer with a critical value of 7, the 5th hour to the 12th cut after the end, the time drift rate is shown in Figure 5, close to G亳In practice, the corrected version is preferably close to the ideal model, as shown by the solid line in Figure 5. According to another embodiment of the invention, Figure 6 is - acid sensing and acid testing The response voltage of 12 hours in the buffer solution with a value of 7 is related to the measurement time. The original time drift signal is in the correction circuit to - After 5% > ^ correction (adjust R2), the time drift rate is ι 〇 (mV / h). ^ J ^ According to another embodiment of the present invention, the acidity of the acid sensor is 3, 7, 9 o'clock acid response as shown in Figure 7. The results show that the 201104277 system of the present invention has a sensitivity to acid and alkali of 38.968 mV / pH (mV / pH), linearity - According to another embodiment of the present invention, FIG. 8 is a graph showing the relationship between the response voltage and the measurement time of an acid-base sensor in a buffer solution at a pH of 7 hours, wherein the original time drift signal After passing through the correction circuit with an AV = - positive, the time drift rate is known to be 0.268 mV / h (mV / h). According to another embodiment of the present invention, the pH value of the acid-base sensor is between 3 The acid-base response at 5, 7, and 9 is shown in Figure 9. The results show that the system of the present invention has a sensitivity of 10.469 mV/acid test (mV/pH) and a linearity of 0.988 for acid test. Finally, those skilled in the art will recognize that they can easily use the notion of disclosure and specific embodiments to change and design other knots that can perform the same purpose. The present invention does not depart from the scope of the invention and the scope of the patent application. 201104277 [Simplified description of the drawings] FIG. 1 is a diagram illustrating the structure of the drift-correcting electric circuit according to an embodiment of the present invention; FIG. 2 is a diagram illustrating the drifting according to an embodiment of the present invention. Correction of the architecture of the sensing system; FIG. 3 illustrates the structure of the bismuth citrate sensing element according to an embodiment of the present invention; FIG. 4 is a graph showing the actual time lapse of the buffer solution of pH 7; The figure shows the ideal time-lapse curve of the buffer solution of pH 7 and the calibration time-lapse curve; Figure 6 shows the time-lapse curve of the buffer solution with the corrected pH 7 according to the embodiment of the present invention. Figure 7 is a schematic diagram showing corrected sensitivity and linearity; Figure 8 is a time-lapse graph showing a corrected pH 7 buffer solution according to another embodiment of the present invention; The graph shows a schematic of the corrected sensitivity and linearity. [Main component symbol description] 100~ time drift correction circuit; 101~first instrumentation amplifier; 102~second instrumentation amplifier; 103~inverting amplifier 104~adder; 200~time drift correction sensing system; · 12 201104277 201 ~ voltage acid-base sensing element; 202 ~ digital precision meter; 203 ~ data logger; 204 ~ reference electrode; 205 ~ thermocouple; 206 ~ PID temperature controller; 207 ~ heater device; 208 ~ black box; 〇 9 ~ buffer solution; 301 ~ substrate; 302 ~ sensing film; 303 ~ insulating layer.
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