TWI414785B - Ph value measuring system - Google Patents

Abstract

A pH value measuring system includes: a pH sensor device including a flexible sensor array; a reference electrode; and a read out circuit module coupled to the flexible sensor array. The pH value measuring system further includes a data acquisition module coupled to the readout circuit module; and a weighted data fusion calculation module coupled to the data acquisition module. A pH value of a sample solution is obtained by performing a weighted data fusion calculation with the measurement values of the sample solution obtained from the flexible sensing array by the weighted data fusion calculation module.

Description

pH measurement system

The present invention relates to a pH measurement system, and more particularly to a pH measurement system that combines a flexible acid-base sensing array with a weighted fusion operation module that performs weighted data fusion operations on measured values.

And J. Van Der Spiegel et al. (J. Van der Spiegel, I. Lauks, P. Chan D. Babic, 1983, "The extended gate chemical sensitive field effect transistor as multi-species microprobe", Sensors and Actuators B, Vol. 4, pp. 291-298.), in 1983, the component of the discrete ion-sensing field-effect transistor was proposed as a horizontal array structure, which contained four sensing parts, respectively, using IrO _x deposited on the gate. Different sensing films such as LaF ₃ , AgCl and Ag ₂ S can be used as sensors for detecting four ions of H ⁺ , F ^- , Cl ^- and Ag ⁺ .

The Republic of China Invention Patent No. I258173 discloses a polycrystalline germanium film transistor ion sensing device and a manufacturing method thereof. It forms a polycrystalline germanium film transistor ion sensing device on the glass substrate. The device comprises an ion sensing portion, a signal processing circuit, a driving circuit, and a display area. The sensing film is an enzyme film, a cerium oxide, a cerium nitride, an aluminum oxide, a titanium oxide, and an oxide of cerium, and different sensing films can be replaced according to different analytes, because the ion sensing device The system integrates the system on a glass substrate, thus achieving the goal of integrating the sensing elements.

The Republic of China invention patent No. I295729 discloses a preparation method of a pH sensor, and the prepared pH sensor includes a system of the pH sensor and a measurement method. The invention utilizes a reactive sputtering method to prepare a titanium nitride extended sensing field effect transistor, and the advantage of the titanium nitride as the sensing film of the acid-base sensor has a lower sheet resistance (Sheet Resistance) ), better conductivity, high melting point (Melting Point: 2930 ° C), very stable high temperature characteristics, good adhesion in the metal interface, and corrosion resistance, can withstand higher acid and alkali solutions.

The invention provides a pH measuring system, comprising: an acid-base sensing device comprising: a flexible acid-base sensing array. The flexible acid-base sensing array includes a flexible substrate; a first insulating layer on the flexible substrate; a plurality of conductive layers on the first insulating layer; and a plurality of wires on the first insulating layer Each of the plurality of conductive layers is in contact with the plurality of conductive layers, wherein the plurality of conductive layers and the plurality of wires form a plurality of flexible acid-base sensing electrodes, wherein the acid-base sensing device performs a test solution for n times Measured, and n is an integer greater than 1, and each of the flexible acid-base sensing electrodes generates a signal for each measurement, and each of the flexible acid-base sensing electrodes generates n signals. The acid-base sensing device further includes a reference electrode; and a readout circuit module coupled to the flexible acid-base sensing array for respectively receiving n signals generated by each of the flexible acid-base sensing electrodes . The pH measuring system further includes: a data capturing module coupled to the readout circuit module, configured to convert n signals generated by each of the flexible acid-base sensing electrodes into the respective flexible acids The n measured values measured by the alkali sensing electrode; and a weighted fusion computing module coupled to the data capturing module for weighting all the measured values converted by the data capturing module to generate The pH value of the test solution.

The above and other objects, features and advantages of the present invention will become more apparent from

In the present invention, the flexible acid-base sensing array is combined with a weighted fusion operation module for performing weighted data fusion calculations to obtain a flexible, easy-to-carry biomedical sensing. Product, and a pH measurement system that reduces measurement errors caused by a single sensor.

Figure 1 shows a schematic diagram of a pH measuring system 100 in accordance with one embodiment of the present invention. The pH measurement system 100 can include an acid-base sensing device 101, a data acquisition module 103, and a weighted fusion operation module 105.

The acid-base sensing device 101 can include a flexible acid-base sensing array 107, a reference electrode 109, and a readout circuit module 111. The flexible acid-base sensing array 107 can include a plurality of flexible acid-base sensing electrodes 113. The readout circuit module 111 is coupled to the plurality of flexible acid-base sensing electrodes 113 and the reference electrode 109, wherein the reference electrode 109 is used to provide a stable voltage. In an embodiment, the reference electrode can comprise a silver/silver chloride reference electrode.

See Figures 2a and 2b. In one embodiment, the method of forming the flexible acid-base sensing array 107 of the acid-base sensing device 101 is as follows.

First, a flexible substrate 201 is provided, and a first insulating layer 203 is provided on the flexible substrate 201. Then, a plurality of conductive layers 205 are formed on the first insulating layer 203, and a plurality of wires 207 are formed on the first insulating layer 203 and respectively contact with the plurality of conductive layers 205 to form a plurality of flexible acid-base sensing electrodes. 113. The material of the flexible substrate 201 may include polyethylene terephthalate, polyether oxime or polycarbonate. The material of the first insulating layer 203 may include epoxy resin, epoxy-polyurethane or ultraviolet light insulating glue. The material of the conductive layer 205 may include indium tin oxide, tantalum nitride, hafnium oxide or titanium dioxide, and the conductive layer 205 may be fixed on the first insulating layer 203 by radio frequency sputtering (RF sputtering). The wires can be formed by screen printing. Also, the plurality of flexible acid-base sensing electrodes 113 may include 2, 4 or 8 sensing electrodes.

In another embodiment, the flexible acid-base sensing array 107 further includes a second insulating layer 209 on the plurality of conductive layers 205 and the plurality of wires 207, wherein the second insulating layer 209 has a plurality of openings 211 Portions of the plurality of conductive layers 205 are respectively exposed to form a plurality of sensing windows 211a, and the plurality of sensing windows 211a may include 2, 4 or 8 sensing windows. The second insulating layer 209 exposes one end of the plurality of wires 207 contacting the conductive layer 205 as an external electrical contact. The material of the second insulating layer may include epoxy resin, epoxy-polyurethane or ultraviolet light insulating glue.

In still another embodiment, referring to FIG. 3, the reference electrode 109 can be located on the same substrate as the plurality of flexible acid-base sensing electrodes 113 described above. A reference electrode layer 213 is formed between the flexible substrate 201 and the first insulating layer 203, and the first insulating layer 203 has at least one opening 215 exposing a portion of the reference electrode layer 213 to form a plurality of flexible acid-base sensations The measuring electrode 113 is located on the reference electrode 109 on the same substrate 101. The reference electrode layer may include a metal layer and a conductive polymer layer on the metal layer (not shown). The material of the metal layer may include copper, aluminum or silver, and the material of the conductive polymer layer includes polyfluorene, polyaniline or polythiophene. In an embodiment, the reference electrode layer 213 can be a T-shape, wherein the T-shaped end is an external electrical contact.

In addition, in the embodiment where the reference electrode 109 and the plurality of flexible acid-base sensing electrodes 113 are located on the same substrate, the flexible acid-base sensing array 107 may further include a second insulating layer 209. The conductive layer 205 and the plurality of wires 207, wherein the second insulating layer 209 has a plurality of openings 211 respectively exposing portions of the plurality of conductive layers 205 to form a plurality of sensing windows 211a, and the plurality of sensing windows 211a may include 4 or 8 sensing windows. In addition, the second insulating layer 209 exposes one end of the plurality of wires 205 not contacting the conductive layer 205 as an external electrical contact, and the second insulating layer 209 further has at least one opening 215 exposing the first insulating layer 203. The opening 215' exposes the reference electrode 109. The material of the second insulating layer may include epoxy resin, epoxy-polyurethane or ultraviolet light insulating glue.

Referring again to FIG. 1, the acid-base sensing device 101 performs n measurements on a liquid to be tested 123, and n is an integer greater than 1, and each of the flexible acid-base sensing electrodes 113 generates one measurement per measurement. The signal, therefore, each of the flexible acid-base sensing electrodes 113 generates n signals. The readout circuit module 111 is configured to receive n signals generated by each of the flexible acid-base sensing electrodes 113.

The data capture module 103 is coupled to the readout circuit module 111 for converting the n signals generated by the flexible acid-base sensing electrodes 113 into the respective flexible acid-base sensing electrodes 113. n measured values. The weighted fusion computing module 105 is coupled to the data capture module 103 for performing a weighted fusion operation on all measured values converted by the data capture module 103 to generate a pH value of the liquid to be tested.

In addition, the weighted fusion operation module 105 may include an arithmetic average operation unit 115, a standard deviation operation unit 117, a weighting coefficient operation unit 119, and a total operation unit 121.

The arithmetic average operation unit 115 is coupled to the data acquisition module 103 for calculating an average value of the n measurement values derived from the flexible acid-base sensing electrodes 113 converted by the data acquisition module 103. The standard deviation operation unit 117 is coupled to the arithmetic average operation unit 115 for generating a standard deviation of the n measurement values based on the n measurement values and the average value thereof. The weighting coefficient operation unit 119 is coupled to the standard deviation operation unit 117 for generating weighting coefficients corresponding to the respective flexible acid-base sensing electrodes 113 according to all standard deviations belonging to the respective flexible acid-base sensing electrodes 113. . The total operation unit 121 is coupled to the arithmetic average operation unit 115 and the weighting coefficient operation unit 119 for multiplying the average value of the n measurement values of each of the flexible acid-base sensing electrodes 113 by the respective flexible acids. The weighting coefficients of the alkali sensing electrodes 113 are used to generate weighting values of n measured values of the respective flexible acid-base sensing electrodes 113, and all the weighting values are summed to generate a weighted fusion value. The weighted fusion value represents the pH value of the liquid to be tested.

In another embodiment, the data capture module 103 and the weighted fusion operation module 105 can be located in a personal computer 407, as shown in FIG.

Referring to FIG. 4, the pH measurement system 400 can further include an extension plate 405, and the readout circuit module 111 can further include an amplification circuit 401 and a filter 403. The amplifying circuit 401 is interposed between the flexible acid-base sensing array 107 and the filter 403 and coupled to the signal for amplifying the signal from the flexible acid-base sensing array 107. The filter module 403 is also used to filter out noise. The extension board 405 is interposed between the readout circuit module 111 and the personal computer 407 for coupling the filter 403 and the data capture module 103.

The weighted fusion operation performed by the weighted fusion operation module 105 composed of the arithmetic mean operation unit 115, a standard deviation operation unit 117, a weighting coefficient operation unit 119, and a total operation unit 121 will be further described below.

Weighted fusion operation: The standard deviation is a measure of the degree to which a set of data is dispersed from the mean. A larger standard deviation represents a larger difference between most of the data and the average, and a smaller standard deviation means that most of the data is closer to the average. Suppose a sensing electrode measures one of the set data as x ₁ , x ₂ , x ₃ ,..., x _n (both real numbers), and the average value is as shown in equation (1) (by arithmetic arithmetic unit 115 conducted):

Where n represents the number of measurements and x _i represents each measurement.

The standard deviation of this set of data is as shown in equation (2) (by standard deviation operation unit 117):

Where n represents the number of measurements, x _i represents each measurement, Represents the average of the n measurements measured for each acid-base sensing electrode.

Consider the case where m sensing electrodes measure a one-dimensional target. For different weighting coefficients, in order to minimize the total mean square error, the measured values obtained by the sensing electrodes are self-adaptive to find the optimal weighting coefficient of each sensing electrode, so that the data is fused. The value is closest to the true value.

Let the variances of the m sensing electrodes be The true value to be estimated is X, and the average value of the measured values of each sensing electrode is Independent of each other, and is an unbiased estimation of X. The weighting coefficients of the sensing electrodes are w ₁ , w ₂ ,..., w _m , respectively, and the values and weighting coefficients of the data fusion need to satisfy the following Relationship:

Among them, the formula (3) is derived from the unbiased estimation, and the total mean square error after data fusion is:

It can be known from equation (5) that the total mean square error σ ² is a multivariate quadratic function of each weighting coefficient, so there must be a minimum value by weighting coefficients w ₁ , w ₂ ,...,w _m satisfies the multivariate function extremum of equation (4). According to the Lagrangian multiplier method, the weighting coefficient corresponding to the minimum total variance can be obtained (by the weighting coefficient operation unit 119), as shown in the formula (6):

Where σ _i represents the standard deviation of n measurements of a particular acid-base sensing electrode and σ _j represents the standard deviation of n measurements of each acid-base sensing electrode.

Taking two sensing electrodes as an example, under the minimum mean value of the mean square, the best estimate of the target data is obtained, as long as the appropriate choice of w ₁ makes the formula (5) minimum, and the equation (6) The partial derivative of ₁ and the partial derivative thereof is equal to zero, which is obtained (by the summation operation unit 121):

Therefore, the best estimate of the data X (performed by the summation operation unit 121) is

The weighting coefficients W ₁ and W ₂ can be obtained by the formula (7). It is known from equation (8) that the smaller the mean square error of the measured values, the larger the corresponding weighting coefficient, that is, the better the reliability of the measured value data. On the contrary, the larger the error mean deviation of the measured values, the smaller the corresponding weighting coefficient, that is, the worse the reliability of the measured value data.

The mean square error of the estimated error is:

Known by equation (9), , i=1, 2, that is, in the sense that the error mean square error is the smallest, the estimation error of the two sensing electrodes after fusion is smaller than that of any single sensing electrode, so the correctness of the sensing result can be increased.

The flexible acid-base sensing array can be used to calculate the weighting coefficient and the result according to the different sensing electrodes according to the formula (6), as shown in Table 1.

The measurement error caused by damage or instability of a single component can be solved by the system of the present invention.

[Examples] Example 1 Formation of a flexible acid-base sensing array (with reference electrode)

See Figure 3. First, a flexible substrate made of polyethylene terephthalate is provided. The substrate 101 was placed in a beaker containing an appropriate amount of acetone solution, and after shaking for 3-5 minutes via an ultrasonic oscillator, the substrate 101 was washed with DI water. Then, the substrate 101 cleaned by the acetone solution is placed in a glass beaker containing an appropriate amount of ethanol solution, and shaken for 5 minutes using an ultrasonic oscillator, and then the substrate 101 is washed with deionized water, and then the substrate 101 is cleaned with dust-free paper. Gently wipe dry.

Next, the T-shaped reference electrode layer 213 was fixed to the substrate 101 with silver paste, and the fixed component was baked in a 120 ° C oven for 20 minutes. Then, an epoxy resin is used as the insulating layer 203 to cover the reference electrode layer 213, and a partial region of the reference electrode layer 213 is exposed for solution detection. The fixed components were then baked in a 140 ° C oven for 40 minutes.

The eight conductive layers 205 are fixed on the insulating layer 215 by radio frequency sputtering (RF sputtering). Then, the eight metal wires 207 are fixed on the insulating layer 215 with silver glue, and are electrically connected to the eight conductive layers 205, respectively. The fixed component was then baked in a 120 ° C oven for 20 minutes. Then, an epoxy resin is used as the insulating layer 209 to fix the portion of the silver paste, and the above components are substantially packaged, leaving about 8 conductive windows 211a having a diameter of 1.5 mm to expose a portion of the conductive layer 205, and An opening is formed that exposes the reference electrode. This component was baked in a 140 ° C oven for 40 minutes to dry the insulating layer 209. The component encapsulated by the insulating layer 209 has good waterproof and insulating effects when sensed in an aqueous solution.

Example 2 pH measurement system

See Figure 4. Providing a flexible acid-base sensing array having 8 sensing electrodes (sensing windows) of the invention (with no reference electrode layer therein) (for forming method, refer to Example 1), and providing a silver/silver chloride Reference electrode 109. The flexible acid-base sensing array and the reference electrode are coupled to the readout circuit module 111 (instrument amplifier IC LT1167), respectively.

The readout circuit module 111 includes an amplification circuit 401 and a filter 403. The amplifying circuit 401 is interposed between the flexible acid-base sensing array 107 and the filter 403 and coupled to the signal for amplifying the signal from the flexible acid-base sensing array 107. The filter module 403 is also used to filter out noise. The data capture module 103 (NI PCI 6010) is coupled to the readout circuit module 111. The extension board 405 is interposed between the readout circuit module 111 and the personal computer 407.

The personal computer 407 has an arithmetic average operation unit 115 coupled to the data acquisition module 103, the standard deviation operation unit 117 is coupled to the arithmetic average operation unit 115, and the weighting coefficient operation unit 119 is coupled to the standard deviation operation unit 117. The arithmetic unit 121 is coupled to the arithmetic mean arithmetic unit 115 and the weighting coefficient arithmetic unit 119. The arithmetic average operation unit 115, the standard deviation operation unit 117, the weighting coefficient operation unit 119, and the total operation unit 121 are executed by the LabVIEW software.

By means of this measurement system, a set of 8 data can be obtained at a time, which are obtained from 8 sensing electrodes respectively.

Example 3 Measurement of a standard buffer solution of pH 7 using the pH measurement system of the present invention

The standard buffer solution of pH 7 was measured by the pH measurement system of Example 2. The flexible acid-base sensing array was contacted with a standard buffer solution of pH 7, 8 sets of data were obtained in one measurement, and 10 repeated measurements were performed. The measurement results are shown in Table 2.

The pH of the pH 7 standard buffer solution measured by the system of the present invention is 6.9972 (weighted fusion operation), and all the data measured by the flexible acid-base sensing array are averaged and fused (measured by each sensing electrode) The average of the average values of the values, the calculated pH 7 standard buffer solution pH is 6.9365, so the results measured by the system of the present invention are closer to the actual value.

Example 4 Measuring different pH buffer solutions with the flexible acid-base sensing array of the present invention

Different pH buffer solutions were measured using the flexible acid-base sensing array of the present invention with 8 sensing electrodes. The measurement results of the respective sensing electrodes are shown in Figs. 5 and 6.

Figure 5 is a graph showing the response voltage/pH of the flexible acid-base sensing array of the present invention with 8 sensing electrodes in different acid-base concentration solutions, and the results show that the array type screen printing sensing device 8 Each detection window has excellent acid-base sensing characteristics.

Figure 6 is a graph showing the calibration curve of the flexible acid-base sensing array of the present invention with 8 sensing electrodes in different acid-base concentration solutions, and the results show the acidity and alkalinity of the array screen printing sensing device. The measure is between 44.31 mV/pH to 56.88 mV/pH.

Example 5 Measuring different beverages with the pH measurement system of the present invention

Different beverages were measured using the pH measurement system of Example 2. The flexible acid-base sensing array was contacted with mineral water (Wei Dan Enterprise Co., Ltd.), milk (weiquan Food Industry Co., Ltd.) and lemon juice (unified enterprise company), and 8 sets of data were obtained in one measurement, and Repeat the measurement 10 times. The measurement results are shown in Tables 3 and 7.

It can be seen from Table 3 and Figure 7 that the pH values of mineral water, milk and lemon juice measured by the system of the present invention are pH 6.6841, pH 6.6453 and pH 5.2476, respectively (weighted fusion operation), and the flexible acid is used. All the data measured by the alkali sensing array were averaged (average of the average of the measured values of the sensing electrodes), and the calculated pH values of mineral water, milk and lemon juice were pH 7.008, pH 7.0365 and pH 4.915. Based on the pH values of mineral water, milk and lemon juice measured by the acid-base detector (pH 6.57, pH 6.74 and pH 5.79, respectively), the results obtained by the system of the present invention are relatively accurate.

While the present invention has been described in its preferred embodiments, the present invention is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

100, 400. . . pH measurement system

101. . . Acid-base sensing device

103. . . Data capture module

105. . . Weighted fusion computing module

107. . . Flexible acid-base sensing array

109. . . Reference electrode

111. . . Readout circuit module

113. . . Flexible acid-base sensing electrode

115. . . Arithmetic arithmetic unit

117. . . Standard deviation unit

119. . . Weighting coefficient unit

121. . . Total arithmetic unit

123. . . Test solution

201. . . Flexible substrate

203. . . First insulating layer

205. . . Conductive layer

207. . . wire

209. . . Second insulating layer

211. . . Opening

211a. . . Sensing window

213. . . Reference electrode layer

215, 215’. . . Opening

401. . . amplifying circuit

403. . . filter

405. . . Extension board

407. . . personal computer

Fig. 1 shows a pH measuring system according to an embodiment of the present invention.

Figure 2a shows an exploded view of a flexible acid-base sensing array in accordance with one embodiment of the present invention.

Figure 2b shows a cross-sectional view of a flexible acid-base sensing array in accordance with one embodiment of the present invention.

Figure 3 shows an exploded view of a flexible acid-base sensing array in accordance with another embodiment of the present invention.

Fig. 4 shows a pH measuring system according to another embodiment of the present invention.

Figure 5 is a graph showing the response voltage/pH curve obtained by the flexible acid-base sensing array of the present invention in different acid-base concentration solutions.

Figure 6 is a graph showing the calibration curve obtained by the flexible acid-base sensing array of the present invention in different acid-base concentration solutions.

Figure 7 shows the results of measuring the pH values of mineral water, milk, and lemon juice using different methods or systems.

100. . . pH measurement system

101. . . Acid-base sensing device

103. . . Data capture module

105. . . Weighted fusion computing module

107. . . Flexible acid-base sensing array

109. . . Reference electrode

111. . . Readout circuit module

113. . . Flexible acid-base sensing electrode

115. . . Arithmetic arithmetic unit

117. . . Standard deviation unit

119. . . Weighting coefficient unit

121. . . Total arithmetic unit

123. . . Test solution

Claims (24)

A pH measuring system comprising: an acid-base sensing device comprising: a flexible acid-base sensing array comprising: a flexible substrate; a first insulating layer on the flexible substrate; a plurality of conductive layers on the first insulating layer; and a plurality of wires respectively contacting the plurality of conductive layers on the first insulating layer, wherein the plurality of conductive layers and the plurality of wires form a plurality of flexible acids and bases a sensing electrode, wherein the liquid to be tested is measured n times by the acid-base sensing device, and n is an integer greater than 1, and each of the flexible acid-base sensing electrodes generates a signal for each measurement, each of which The flexible acid-base sensing electrodes respectively generate n signals; a reference electrode; and a readout circuit module coupled to the flexible acid-base sensing array for respectively receiving the flexible acid-base sensing The n signals generated by the electrodes; a data capture module coupled to the readout circuit module for converting the n signals generated by each of the flexible acid-base sensing electrodes into the flexible acid and alkali n measured values measured by the sensing electrode; and a weighted fusion operation module and the The data capture module is coupled to perform weighting operation on all the measured values converted by the data capture module to generate a pH value of the liquid to be tested. The pH measuring system according to claim 1, wherein the material of the flexible substrate comprises polyethylene terephthalate, polyether oxime or polycarbonate. The pH measuring system of claim 1, wherein the material of the first insulating layer comprises an epoxy resin, an epoxy-polyurethane or an ultraviolet light insulating adhesive. The pH measuring system of claim 1, wherein the plurality of flexible acid-base sensing electrodes comprise 2, 4 or 8 sensing electrodes. The pH measurement system according to claim 1, wherein the material of the conductive layer comprises indium tin oxide, tantalum nitride, hafnium dioxide or titanium dioxide. The pH measuring system of claim 1, wherein the conductive layer is fixed to the first insulating layer by radio frequency sputtering. The pH measurement system of claim 1, wherein the material of the wire comprises copper, aluminum or silver. The pH measurement system of claim 1, wherein the wire is formed by screen printing. The pH measuring system of claim 1, further comprising a second insulating layer on the plurality of conductive layers and the plurality of wires, wherein the second insulating layer has a plurality of openings respectively exposing the plurality Conductive layers to form a plurality of sensing windows. The pH measurement system of claim 9, wherein the plurality of sensing windows comprises 2, 4 or 8 sensing windows. The pH measuring system of claim 9, wherein the material of the second insulating layer comprises an epoxy resin, an epoxy-polyurethane or an ultraviolet light insulating adhesive. The pH measuring system of claim 1, wherein the reference electrode is formed on the first insulating layer by forming a reference electrode layer between the flexible substrate and the first insulating layer. Forming at least one opening to expose a portion of the reference electrode layer. The pH measuring system of claim 12, wherein the acid-base sensing device, wherein the reference electrode layer comprises: a metal layer; and a conductive polymer layer on the metal layer. The pH measuring system according to claim 13, wherein the acid-base sensing device, wherein the material of the metal layer comprises copper, aluminum or silver. The pH measuring system according to claim 13, wherein the acid-base sensing device, wherein the conductive polymer layer comprises polyfluorene, polyaniline or polythiophene. The pH measuring system of claim 12, further comprising a second insulating layer on the plurality of conductive layers and the plurality of wires, wherein the second insulating layer has a plurality of openings respectively exposing the plurality of openings Portions of the conductive layer to form a plurality of sensing windows, and exposing at least one opening of the first insulating layer to expose the reference electrode. The pH measurement system of claim 16, wherein the plurality of sensing windows comprises 2, 4 or 8 sensing windows. The pH measuring system of claim 16, wherein the material of the second insulating layer comprises an epoxy resin, an epoxy-polyurethane or an ultraviolet light insulating adhesive. The pH measurement system of claim 1, wherein the reference electrode comprises a silver/silver chloride reference electrode. The pH measurement system of claim 1, wherein the readout circuit module is coupled to each of the flexible acid-base sensing electrodes and the reference electrode. The pH measurement system of claim 1, wherein the weighted fusion operation module comprises: an arithmetic average operation unit coupled to the data acquisition module for separately calculating the data acquisition module Converting an average value of n measured values from each of the flexible acid-base sensing electrodes; a standard deviation computing unit coupled to the arithmetic average computing unit for determining the n measured values and their averages The value is generated by the standard deviation of the n measured values; a weighting coefficient operation unit is coupled to the standard deviation operation unit for generating corresponding to each of the standard deviations respectively belonging to each of the flexible acid-base sensing electrodes a weighting coefficient of the flexible acid-base sensing electrode; and a sum total operation unit coupled to the arithmetic average operation unit and the weighting coefficient operation unit for n measurements of each of the flexible acid-base sensing electrodes The average value is multiplied by a weighting coefficient corresponding to each of the flexible acid-base sensing electrodes to generate a weighted value of n measured values of each of the flexible acid-base sensing electrodes, and all of the weighting values are added Always produce a weighted Value, wherein the weighting value is the fusion of the pH was measured. The pH measurement system of claim 21, wherein the data acquisition module and the weighted fusion operation module are located in a personal computer. The pH measuring system of claim 1, wherein the readout circuit module further comprises: a filter for filtering noise; and an amplifying circuit between the flexible acid and alkali The sensing device and the filter are coupled to the two to amplify signals from the acid-base sensing device. The pH measurement system of claim 23, further comprising an extension board interposed between the readout circuit module and the personal computer for coupling the filter and the data capture module .