comb-shaped sensor element with electrodes on the projections and edge connector at the opposing edge

Abstract: A sensor wherein projection sections (2) are provided at every predetermined distance at predetermined positions on an edge section of a plate shape base body (1), at least an active electrode (2a) and a counter-electrode (2b) being provided at predetermined positions of each projection section (2), and lead-out terminals (3a) are provided at predetermined positions of the substarte (1) facing the part where the projection sections are formed, the substrate (1) having wirings (1a) for electrically connecting both the active electrodes (2a) and the counter-electrode (2b) to the lead-out terminals (3a). By employing this arrangement, measurement labor is greatly reduced and dispersion in measurement data is greatly reduced. In addition, limitation in a number of objects is lightened which can be measured at one measurement operation.

Description: The present invention relates to a sensor. More particularly, the present invention relates to a sensor which is suitable for performing measurement of objects (for example, test solution) using a micro-plate which has object housing chambers of multiple lines and multiple columns. Background Art From the past, a micro-plate (a micro-plate for a high throughput system) is supplied which has object housing chambers (cells) of multiple lines and multiple columns. The micro-plate determined its specification in size, number of cells, pitch between cells and the like. The micro-plate is popularly supplied which has cells of 8-lines and 12-columns. When a dissolved oxygen amount is to be measured, for example, a sensor is employed in the past which is arranged as a single sensor. That is, the sensor arranged as a single sensor is intruded in one cell so that the sensor is contacted to the object which is housed within the cell and that an electrical signal is output therefrom which represents a measurement result. When the above measurement is carried out, the sensor or multiple sensors should be contacted to the object by intruding the sensor arranged as a single sensor into each cell sequentially, or by intruding multiple sensors each being arranged as a single sensor into corresponding cells, so that disadvantages arise in that much labor is required for the measurement and that dispersion is generated in measerement data. Further, a disadvantage arises in that a number of objects is limited which can be measured at one measuring operation, because of spatial limitation and limitation in measurement labor. From the US 4,160,205, a sensor is known for detecting bacterial activity. This sensor comprises a row of test tubes which are supported by a tapered stopper which is fixed to the lower side of a plastic strip. The plastic strip encloses connecting wires. Each stopper supports a coaxial electrode probe which is connected via a wire to pins of a terminal. The terminal is provided at a side of the plastic strip and projects upwardly therefrom. From WO 86 03837 a sensor is known, which consists of a printed circuit board, on which a plurality of pins are formed. These pins forms electrodes and are adapted to project downwardly into the wells of a conventional microtitre plate. Such a board may be provided with an edge connector. EP 170 875 discloses a coplanar arrangement of a base plate, three electrode sections and an edge connector. Each electrode section is provided with a loading area to receive a drop of sample liquid. The present invention was made in view of the above problems. It is an object of the present invention to offer a sensor which can greatly reduce measurement labor. Disclosure of Invention This object is achieved by the features of claim 1. Further advantageous features are subject-matters of the dependent claims. When the sensor of claim 1 according to the present invention is employed, multiple electrode sections and multiple lead-out terminals can be handled in one body, labor for measurement is greatly reduced and dispersion in measurement data is greatly reduced, a spatial limitation and limitation in measurement labor are greatly reduced, and, limitation in a number of objects which can be measured at one measurement operation is lightened, because the sensor disposes multiple electrode sections at every predetermined distance, each electrode section having at least an active electrode and a counter-electrode, unites the all electrode sections and multiple lead-out terminals which output measurement signals of each electrode section. Further, the operation and effects can be realized, because the sensor comprises a base body having a plate shape, projection sections provided at an outer predetermined position at every predetermined distance, at least an active electrode and a counter-electrode provided at a predetermined position of each projection section, and multiple lead-out terminals for outputting measurement signals of each electrode section, the lead-out terminal being provided at a predetermined position of the base body which position opposes to a portion at which the projection section is provided. When the sensor of claim 2 is employed, the measurement signals which are low in their level are immediately amplified so that noise resistance is improved, and an operation and effects can be realized which are similar to those of claim 1, because the sensor further comprises a connector which is connected to the lead-out terminals in a removable manner and an amplifier which amplifies the measurement signals output through the lead-out terminals, wherein the connector and the amplifier are united in one body. When the sensor of claim 3 is employed, limitation in a number of objects which can be measured at one measurement operation is further lightened, and, an operation and effects can be realized which are similar to those of claim 2, because the sensor employs a connector which connects multiple base bodies in parallel to one another and in a removable manner, and employs an amplifier which amplifies measurement signals, respectively, each measurement signal being output through the corresponding lead-out terminal. Brief Description of the Drawings Figure 1 is a front view illustrating a sensor of an embodiment according to the present invention; Figure 2 is a schematic view illustrating a condition for measuring objects using the sensor having the arrangement illustrated in Fig. 1; Figure 3 is a schematic view illustrating a condition for measuring objects using the sensor having the arrangement illustrated in Fig. 1; Figure 4 is a schematic vertical cross-sectional view illustrating a modified example of Fig. 3; Figure 5 is a diagram illustrating a sensor of another embodiment according to the present invention; Figure 7 is an electrical circuit diagram illustrating an electrical arrangement of an amplifier; Figure 8 is an electrical circuit diagram illustrating another electrical arrangement of an amplifier; Figure 9 is an electrical circuit diagram illustrating a further electrical arrangement of an amplifier; Figure 10 is an electrical circuit diagram illustrating a yet electrical arrangement of an amplifier; Figure 11 is a diagram illustrating a measurement results representing changes in dissolved oxygen amount within an object which is made of only culture medium and within an object which is made by adding colibacillus (E.coli) of final concentration of 5 X 10 6 /ml to culture medium, the dissolved oxygen amount being measured using a partial electrode sections of the sensor illustrated in Fig. 1; Figure 12 is a block diagram illustrating an electrical arrangement corresponding to Fig. 3; Best Mode for Carrying Out the Invention Hereinafter, referring to the attached drawings, we explain a sensor of embodiments according to the present invention in detail. Fig. 1 is a front view illustrating a sensor of an embodiment according to the present invention. The sensor comprises an insulation substrate 1 having a square shape in its entirety, first projection sections 2 formed at every predetermined distance on one longer edge of the insulation substrate 1, and a second projection section 3 on the other longer edge of the insulation substrate 1, the second projection section 3 having a predetermined width. And, an active electrode 2a, a counter-electrode 2b and a reference electrode 2c are formed on a surface of each first projection section 2, the active electrode 2a, the counter-electrode 2b and the reference electrode 2c consist an electrode section. Further, multiple lead-out terminals 3a are formed on a surface of the second projection section 3 at every predetermined distance. And, multiple wirings 1a are formed so that each active electrode 2a, each counter-electrode 2b and each reference electrode 2c are connected to corresponding lead-out terminals 3a through corresponding wirings 1a. It is preferable that the active electrodes 2a, the counter-electrodes 2b, the reference electrodes 2c, the lead-out terminals 3a and the wirings 1a are formed using printing technique. Further, the sensor having the above arrangement may be a sensor which detects a dissolved oxygen amount within an object, or may be a sensor which detects hydrogen peroxide. Fig. 2 is a schematic diagram illustrating a measurement condition for measuring objects using the sensor having the arrangement illustrated in Fig. 1. In Fig. 2, reference numeral 4 represents a micro-plate. Cells 4a are formed at every predetermined distance in the micro-plate 4, and objects 4b are housed within the cells 4a, respectively. And, the first projection sections 2 of the sensor having the arrangement illustrated in Fig. 1 are intruded into corresponding cells 4a so that the electrode section and the object are contacted to one another. The lead-out terminals 3a on the second projection section 3 of the sensor are connected to a connector 5, and the connector 5 is connected to a signal processing apparatus 8 such as a computer through an electric wire 6 and an amplifier 7. Further, an end-point method, a rate method which are known from the past may be employed as a signal processing method. As is apparent from Fig. 2, a plurality of electrode sections can be intruded within corresponding cells 4a by one handling operation. Also, a plurality of lead-out terminals 3a can be connected to the connector 5 by one handling operation. Therefore, entire labor for measurement is greatly reduced. Further, the first projection sections 2 are determined their distances so that each first projection section 2 corresponds to each cell 4a. Therefore, spatial limitation and limitation in measurement labor are greatly reduced. Further, limitation in a number of objects which can be measured at one measurement operation is lightened. Furthermore, contacting condition of all electrode sections and objects, temperature circumstance, and connecting condition of all lead-out terminals 3a and the connector 5 are made to be almost equal to one another so that dispersion in measurement data is greatly reduced. Fig. 3 is a schematic diagram illustrating a measurement condition for measuring objects using the sensor having the arrangement illustrated in Fig. 1. The measurement condition in Fig. 3 is different from the measurement condition in Fig. 2 in that the measurement condition in Fig. 3 employs a connector 5 which is connected to multiple sensors each having the arrangement illustrated in Fig. 1, the sensors being in parallel to one another, and the connector 5 holding multiple sensors, and that an amplifier 7 is provided to the connector 5 in one body. Arrangement of other sections are the same to those of Fig. 2. When the measurement condition illustrated in Fig. 3 is employed, a number of objects which can be measured at one measurement operation is greatly increased similarly to Fig. 2. Further, the measurement signals output from the sensor through the lead-out terminals 3a and the connector 5 are supplied to the amplifier 7 immediately under the measurement condition illustrated in Fig. 3, therefore, effects of noises to the measurement signals which are prior to amplification, are greatly reduced in comparison to the measurement condition illustrated in Fig. 2 so that measurement accuracy is greatly improved. Furthermore, operations and effects are realized which are similar to those of Fig. 2. Fig. 12 is a block diagram illustrating an electrical arrangement corresponding to this embodiment. Measurement signals output from a plurality of sensors S are amplified by corresponding pre-amplifier P, and the amplified measurement signals are selectively supplied to a signal processing apparatus 8 through a multiplexer M, respectively. The signal transmission between the multiplexer M and the signal processing apparatus 8 can be performed using a wiring, or can be performed by communication using RS232C. Further, smoothing processing or the like may be performed within the signal processing apparatus 8 for a counterplan against noises, but similar processing may be performed within each pre-amplifier P by incorporating a micro-computer to each pre-amplifier P. When the measurement condition illustrated in Fig. 3 is to be employed, and when guide rails 10 are provided at edge sections of a table 9, the table 9 positioning and supporting a micro-plate 4, and when engaging sections 11 for engaging the guide rails 10 are provided at edge sections of the connector 5, the first projection sections 2 can be intruded within corresponding cells 4a by only pressing the connector 5 downwards so that handling operability is improved. Fig. 5 is a diagram illustrating a sensor of another embodiment according to the present invention. In Fig. 5, a right half portion represents a front view, while a left half portion represents a rear view. In the sensor illustrated in Fig. 5, active electrodes 2a and reference electrodes 2c are formed on a front side surface of each first projection section 2, and counter-electrodes 2b are formed on a rear side surface of each first projection section 2. Therefore, an area of the active electrode 2a can be increased in comparison to the sensor illustrated in Fig. 1, the area giving the greatest affect to the measurement signal intensity, so that a measurement sensitivity is improved. Further, operations and effects are realized which are similar to those of Fig. 1. Fig. 7 is an electric circuit diagram illustrating an electric arrangement of an amplifier 7 of an example. This amplifier 7 corresponds to an electrode section which consists an active electrode and a counter-electrode. Further, in Fig.7, the active electrode is represented with "W", while the counter-electrode is represented with "C". In this amplifier 7, an output signal from the active electrode is supplied to a non-reverse input terminal of an operational amplifier 51, a reverse input terminal of the operational amplifier 51 is connected to the ground GND, a resistor 52 is connected between the non-reverse input terminal and an output terminal of the operational amplifier 51, and an output signal from the output terminal is output as an amplified signal. Further, a bias voltage is applied to a non-reverse input terminal of an operational amplifier 53, a reverse input terminal of the operational amplifier 53 is connected to the ground GND, a resistor 54 is connected between the non-reverse input terminal and an output terminal of the operational amplifier 53, and an output voltage from the output terminal is applied to the counter-electrode. Therefore, the bias voltage is applied to the counter-electrode through the operational amplifier 53. Under this condition, the measurement signal output from the active electrode is amplified by the operational amplifier 51, and the amplified measurement signal is output from the operational amplifier 51. Fig.8 is an electric circuit diagram illustrating an electric arrangement of an amplifier 7 of another example. This amplifier 7 corresponds to an electrode section which consists an active electrode, a counter-electrode and a reference electrode. Further, in Fig.8, the active electrode is represented with "W", the counter-electrode is represented with "C", and the reference electrode is represented with "R". In this amplifier 7, a bias voltage is applied to a non-reverse input terminal of an operational amplifier 55 through a resistor 56, a reverse input terminal of the operational amplifier 55 is connected to the ground GND, and an output voltage output from an output terminal of the operational amplifier 55 is applied to the counter-electrode. Further, an output signal from the reference electrode is supplied to a reverse input terminal of an operational amplifier 57, a non-reverse input terminal and an output terminal of the operational amplifier 57 are connected with short circuit (directly) to one another, and an output voltage from the output terminal is applied to the non-reverse input terminal of the operational amplifier 55 through a resistor 58. Furthermore, diodes 59 and 60 are connected in parallel and in reverse polarity to one another between the non-reverse input terminal and the reverse input terminal of the operational amplifier 57. Further, an output signal from the active electrode is supplied to a reverse input terminal of an operational amplifier 61, a resistor 62 is connected between a non-reverse input terminal and an output terminal of the operational amplifier 61, and an output signal from the output terminal is output as an amplified signal. Furthermore, a predetermined positive voltage and a predetermined negative voltage are applied to the non-reverse input terminal of the operational amplifier 61 through diodes 63 and 64, each being connected in reverse polarity, for performing a counterplan for a case where noises or the like are added to the output signal which is supplied to the non-reverse input terminal of the operational amplifier 61, or the like. Therefore, the bias voltage with respect to the reference electrode is applied to the counter-electrode through the operational amplifiers 55 and 57. A measurement signal output from the active electrode under this condition is amplified by the operational amplifier 61, and the amplified measurement signal is output therefrom. Fig. 9 is an electric circuit diagram. illustrating an electric arrangement of an amplifier 7 of a further example. This amplifier 7 corresponds to an electrode section which consists an active electrode, a counter-electrode and a reference electrode. Further, in Fig. 9, the active electrode is represented with "W", the counter-electrode is represented with "C", and the reference electrode is represented with "R". In this amplifier 7, an output signal from the reference electrode is supplied to a non-reverse input terminal of an operational amplifier 65 through a resistor 66, a bias voltage is applied to a reverse input terminal of the operational amplifier 65, a capacitor 67 is connected between the non-reverse input terminal and an output terminal of the operational amplifier 65, and an output voltage from the output terminal of the operational amplifier 65 is applied to the counter-electrode through a resistor 68. Further, an output signal from the active electrode is supplied to a non-reverse input terminal of an operational amplifier 69, a resistor 70 and a capacitor 71 are connected in parallel to one another between the non-reverse input terminal and an output terminal of the operational amplifier 69, and an output signal from the output terminal is output as an amplified signal. Furthermore, a reverse input terminal of the operational amplifier 69 is connected to an adequate bias. Therefore, a bias voltage with respect to the reference electrode is applied to the counter-electrode through the operational amplifier 65. A measurement signal output from the active electrode under this condition is amplified by the operational amplifier 69, and the amplified measurement signal is output therefrom. Fig.10 is an electric circuit diagram illustrating an electric arrangement of an amplifier 7 of a yet example. This amplifier 7 corresponds to an electrode section which consists an active electrode, a counter-electrode and a reference electrode. Further, in Fig. 10, the active electrode is represented with "W", the counter-electrode is represented with "C", and the reference electrode is represented with "R". In this amplifier 7, a bias voltage is applied to a non-reverse input terminal of an operational amplifier 76 through a resistor 77, a reverse input terminal of the operational amplifier 76 is connected to the ground GND, and an output voltage from an output terminal of the operational amplifier 76 is applied to the counter-electrode through a resistor 72. Further, an output signal from the reference electrode is supplied to a reverse input terminal of an operational amplifier 73, a non-reverse input terminal and an output terminal of the operational amplifier 73 are connected with short circuit (directly) to one another, and an output voltage from the output terminal of the operational amplifier 73 is applied to a non-reverse input terminal of an operational amplifier 76 through a resistor 74. Furthermore, an output signal from the active electrode is supplied to the ground GND, voltages at both ends of the resistor 72 are applied to a reverse input terminal and a non-reverse input terminal of an operational amplifier 75, and an output signal from an output terminal of the operational amplifier 75 is output as an amplified signal. Therefore, the bias voltage with respect to the reference electrode is applied to the counter-electrode through the operational amplifiers 73 and 76. And, a measurement signal output from the active electrode under this condition is amplified by the operational amplifiers 75 and 76, and the amplified signal is output therefrom. Fig.11 is a diagram illustrating a measurement results representing changes in dissolved oxygen amount within an object which is made of only culture medium and within an object which is made by adding colibacillus (E.coli) of final concentration of 5 X 10 6 /ml to culture medium, the dissolved oxygen amount being measured using a partial electrode sections of the sensor illustrated in Fig. 1. Further, the horizontal axis represents a time (minutes), while the vertical axis represents a detection current (nA). Furthermore, "a" represents the former case, while "b" represents the latter case. As is apparent from Figs it is understood that the dissolved oxygen amount is decreased due to respiration of colibacillus when colibacillus is added. It is also understood that the dissolved oxygen amount can be measured using the sensor according to the present invention. Further, the dissolved oxygen amount within the object which is made of only culture medium, is gradually decreased. It is thought that the gradually decreasing of the dissolved oxygen amount represents decreasing of the dissolved oxygen amount due to the affection of the electrode section. Industrial Applicability The sensor according to the present invention is available for a sensor which measures objects using a micro-plate having object housing chambers of multiple lines and multiple columns. And, measurement labor is greatly reduced, dispersion in measurement data is greatly reduced, and limitation in a number of objects which can be measured at one measurement operation is lightened.

Claims: A sensor comprising: a base body (1) having a plate shape; at least active electrodes (2a) and counter-electrodes (2b), each active electrode and each counter-electrode constituting one of a plurality of electrode sections; and a multiple lead-out terminal (3a) for outputting measurement signals of each electrode section (2), the lead-out terminal (3a) being provided on the base body (1) wherein said active electrodes (2a) and counter-electrodes (2b) are provided at a predetermined position on projection sections (2) provided at an outer predetermined position on one longer edge of said base body (1) at every predetermined distance; and wherein said lead-out terminal (3a) is provided at a predetermined position which opposes to the portion at which the projection sections (2) are provided, wherein the projection sections (2) and the lead-out terminals are elongated in parallel to one another on a virtual plane comprising the face of said base body (1); and wherein said durality of projection sections can be intruded within corresponding cells (4a) by one handling operation. A sensor as set forth in claim 1, further comprising; a connector (5) which is connected to the lead-out terminals (3a) in a removable manner; and an amplifier (7) which amplifies the measurement signals output through the lead-out terminals (3a); and wherein the connector (5) and the amplifier (7) are united in one body. A sensor as set forth in claim 2, wherein the connector (5) is a connector which connects multiple base bodies (1) in parallel to one another and in a removable manner, the amplifier (7) is an amplifier which amplifies measurement signals, respectively, each measurement signal being output through the corresponding lead-out terminal (3a).

Inventors: OKUMURA CHIAKI, TSUKUDA HIROSHI, OKUMURA, CHIAKI, TSUKUDA, HIROSHI
Applicants: DAIKIN IND LTD, DAIKIN INDUSTRIES, LTD.
Application year: 1998
Main classification: G01N27
IPC codes: G01N27, C40B60, B01L3