WO2015065023A1 - Water quality sensor using positive feedback - Google Patents

Water quality sensor using positive feedback Download PDF

Info

Publication number
WO2015065023A1
WO2015065023A1 PCT/KR2014/010208 KR2014010208W WO2015065023A1 WO 2015065023 A1 WO2015065023 A1 WO 2015065023A1 KR 2014010208 W KR2014010208 W KR 2014010208W WO 2015065023 A1 WO2015065023 A1 WO 2015065023A1
Authority
WO
WIPO (PCT)
Prior art keywords
voltage
optical
detector
photo detector
current
Prior art date
Application number
PCT/KR2014/010208
Other languages
French (fr)
Korean (ko)
Inventor
박영준
최성욱
이상우
Original Assignee
서울대학교 산학협력단
서울바이오시스 주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from KR1020140090256A external-priority patent/KR101644623B1/en
Application filed by 서울대학교 산학협력단, 서울바이오시스 주식회사 filed Critical 서울대학교 산학협력단
Priority to DE112014004937.9T priority Critical patent/DE112014004937B4/en
Priority to US15/026,506 priority patent/US10295519B2/en
Priority to CN201480059243.0A priority patent/CN105765366B/en
Publication of WO2015065023A1 publication Critical patent/WO2015065023A1/en

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/18—Water

Definitions

  • the present invention relates to a water quality sensor using positive feedback.
  • the conventional water quality sensing system using an actuator and a sensor maintains a constant magnitude of an input signal generated from the actuator, so that the sensor detects a change in the medium formed by the actuator.
  • Sensing systems according to the prior art form actuators, media and sensors in a single stage, or form a sensing system in the form of negative feedback for a more stable configuration.
  • the turbidity sensor when the actuator irradiates a constant light to a medium containing a material to measure the concentration, the sensor senses the light transmitted through the medium, and converts the light into an electrical signal to determine the material contained in the medium. The concentration was measured.
  • LOD limit of detection
  • the present invention is to solve the problems of the sensing system according to the prior art described above, and to provide a sensing system that can detect with a higher sensitivity even if a smaller amount of substances are included with improved detection limit characteristics of the present invention.
  • the sensing system has a snapback shape corresponding to an optical actuator that applies an optical stimulus to a detection material and an optical response formed according to the concentration of the detection material to which the optical stimulus is applied.
  • Photo-detector for outputting an electrical signal, an amplifier and electrical signal for amplifying the electrical signal output from the photodetector, and positively applying the amplified electrical signal to an optical actuator. It includes a detection unit for detecting the detection substance is applied.
  • the sensing system according to the present embodiment provides an advantage of detecting a substance to be detected at a concentration low enough to be detected by a conventional sensor.
  • FIG. 1 is a block diagram illustrating an overview of a sensing system according to an embodiment of the present invention.
  • FIG. 2 is a circuit diagram of a sensing system according to an embodiment of the present invention.
  • FIG 3 is a current-voltage characteristic curve of an electrical signal output by a photo detector when detecting a BSA (Bovine Serum Albumin) which is a detection material by the sensing system according to the present embodiment.
  • BSA Bovine Serum Albumin
  • FIG. 4 is a diagram illustrating a measurement result of current-voltage characteristics for each concentration of a substance to be detected in a snapback section.
  • FIG. 5A is a diagram showing a result of BSA measurement measured by a sensor according to the prior art
  • FIG. 5B is a diagram showing a result of BSA measurement measured by this embodiment
  • 5C is a diagram summarizing the BSA detection capability of the sensing system according to the present embodiment.
  • FIG. 6A to 6C are current-voltage characteristic curves of NADH measured using 270, 280, and 340 nm LEDs
  • FIG. 6D is a diagram illustrating NADH measurement capability of the sensing system according to the present embodiment.
  • FIG. 8A to 8C are current-voltage curves obtained by measuring turbidity using 880 nm, 405 nm, and 280 nm infrared LEDs, respectively, and FIG. 8D illustrates measurement limits using a sensing system according to an embodiment of the present invention. Drawing.
  • FIG. 1 is a block diagram illustrating an overview of a sensing system according to an embodiment of the present invention
  • FIG. 2 is a circuit diagram of a sensing system according to an embodiment of the present invention.
  • the sensing system according to the present embodiment includes an optical actuator 100.
  • the optical actuator receives a bias to apply an optical stimulus to the medium 200 including the detection material.
  • actuators providing ultraviolet light, visible light, infrared light and laser light are defined as optical actuators, and sonic wave, supersonic wave, magnetic field, electric field and radioactivity are defined as optical actuators.
  • An actuator that applies a non-optical stimulus such as) is defined as a non-optical actuator.
  • the optical actuator may be implemented as a light emitting diode (LED), a laser diode (LD), or the like which provides light by applying a bias.
  • LED light emitting diode
  • LD laser diode
  • the light emitting diode may emit light in the visible, ultraviolet or infrared wavelength band, and the laser diode may emit laser light having a specific band among the 270 nm to 3330 nm bands. It is desirable to have an optical actuator to irradiate light having a suitable band depending on the properties of the material to be detected by the sensing system.
  • the medium 200 includes a substance to be detected by the sensing system according to the present embodiment.
  • the object to be detected receives an optical stimulus from the optical actuator to form an optical response.
  • the optical response generated by the detection target material to the optical stimulus may be, for example, light from the optical stimulus, light reflected through the medium, light scattered from the medium, or fluorescence formed by the optical stimulus. Can be.
  • BSA Bovine Serum Albumin
  • BSA has a feature of absorbing light of 270 ⁇ 280nm. Therefore, when a laser having a wavelength of 275 nm is irradiated to a medium including BSA, the BSA reacts to the applied optical stimulus to absorb the applied light.
  • this is merely an example for explanation, and the optical response to the optical stimulus generated by the detection material and the optical stimulus applied to the detection material and the detection material may be different.
  • the photo detector 300 detects an optical response generated by applying an optical stimulus to the medium 200 and outputs an optical signal.
  • the optical stimulus applied by the optical actuator is any one of light transmitted through the medium generated by the detection target material, light reflected on the medium, light scattered on the medium, or fluorescence formed by the optical stimulus.
  • the abnormality is detected and an electrical signal is output.
  • the optical response may vary according to the concentration of the detection material included in the medium 200, and accordingly, an electrical signal provided by the photo detector may also vary.
  • a photodetector may be implemented with a photo diode, which detects a change in light due to the optical response in which the medium occurs and provides a corresponding current.
  • the photo detector 300 may receive a driving current i pd from a PD bias for providing a bias current, and the sensing system according to the present embodiment may provide a PD current.
  • the optical response provided by the medium is detected while sweeping the drive current.
  • the photo detector 300 outputs an electrical signal having a snapback shape.
  • the amplifier 400 amplifies and outputs an electrical signal provided by the photo detector, and the amplified electrical signal is added to a bias of the actuator and fed back to the actuator.
  • the actuator 100, the medium 200, the photo detector 300 and the amplifier 400 form a positive feedback path.
  • the amplifier 400 may be implemented as a current-to-voltage converter (iv converter) for converting the current provided by the photodiode in the form of a voltage signal, the output voltage of the current-voltage converter circuit is the bias of the optical actuator ( Positive feedback with ACT bias.
  • iv converter current-to-voltage converter
  • the current i pd provided by the photo detector 300 is converted into a voltage signal v fb by the amplifier 400. Since the voltage signal v fb has a negative potential, the potential of the other end connected to the amplifier 400 is lower than the potential of one end of the optical actuator 100 to which the reference potential is connected. Therefore, as the magnitude of the voltage of the amplifier v fb increases, the bias applied to the optical actuator 100 increases, thereby applying a larger optical stimulus, so that the medium 200 is optically applied to the applied optical stimulus. In response, the photo detector 300 that detects the optical response provides a larger current i pd . That is, it can be seen that the sensing system according to the present embodiment is configured with a positive feedback path.
  • the detector 500 receives the electrical signal output from the photo detector 300 and analyzes the electrical signal to detect the concentration of the detection target material included in the medium 200.
  • the detector 500 includes a read-out circuit to detect the concentration of the detection target material by analyzing the electrical signal OUTPUT provided by the photo detector.
  • FIG. 3 is a current-voltage characteristic curve of an electrical signal output by the photo detector 300 when detecting a BSA (Bovine Serum Albumin) as a sensing material by the sensing system according to the present embodiment.
  • the vertical axis is a value of a bias current (PD bias, i pd ) applied to the photo detector 300 of FIGS. 1 and 2, and the horizontal axis is a voltage value (v pd ) formed across the photo detector 300.
  • the change in voltage across the photodetector will be described while increasing the bias current provided to the photodetector from zero.
  • Increasing the bias current i pd provided to the photo detector 300 correspondingly increases the voltage v pd formed across the photo detector, and the optical actuator 100 is not yet turned on. .
  • the amplifier turns on the optical actuator by applying a voltage higher than the turn-on voltage to the optical actuator.
  • the turned on optical actuator applies an optical stimulus to the medium 200, and when the medium provides light in an optical response, the photo detector detects this light and converts it into a current to output it.
  • the voltage across the light detector must be reduced to compensate for the current caused by the light emitted by the medium by the optical reaction.
  • the voltage moves in a decreasing direction. That is, even if the power source increases the current value applied to the photodetector, the voltage applied across the photodetector is rather reduced in negative resistance.
  • the phenomenon that the voltage across the photodetector decreases as the current applied to the photodetector increases is called a snapback phenomenon, and the starting point at which the snapback phenomenon occurs is a snapback point (SB point) and the current increases due to the snapback phenomenon. Even when the voltage decreases is called a snapback period.
  • SAT point saturation point
  • saturation interval after the saturation point
  • FIG. 3 is a current-voltage characteristic curve obtained with a signal path in an open loop without a positive feedback path. In contrast to the curve shown by the dashed line, it can be seen that the optical actuator, medium, photodetector and amplifier are connected for positive feedback and exhibit snapback characteristics.
  • FIG. 4 is a diagram illustrating a measurement result of current-voltage characteristics of concentrations of a substance to be detected in a snapback section, wherein 1 B, 10 ng, of BSA, which is a substance to be detected in deionized water (DI), ...,
  • the current-voltage curve obtained by the sensing system according to the present example was obtained for the medium to which 1 mg was added.
  • a current of approximately 2.1uA to 2.15uA is applied to the photo detector, a snapback phenomenon occurs, and it can be seen that the voltage is saturated to a voltage of approximately 0V at a current of 2.17uA to 2.21uA.
  • the detector 500 may determine the concentration of the detection target material by fixing the photodetector bias current and reading the voltage across the photodetector, or after fixing the voltage across the photodetector, by reading the value of the photodetector bias current.
  • the detector may fix the photodetector bias current to 2.15uA, and then, when the voltage across the photodetector is read at 66V, the concentration of the detection target material may be 1 ng.
  • the detector may fix the voltage across the photodetector to 40V, and then, when the photodetector bias current is read as 2.18 uA, determine the concentration of the detection target material as 100 ng.
  • the concentration of the substance to be detected may be measured by measuring current and voltage values at the saturation point through the snapback period.
  • FIG. 2 is a circuit diagram of a sensing system implementation according to the present embodiment, wherein a power supply for applying a bias current to the photodetector 300 is Agilent's Model 4156, and the photodetector is an ultraviolet light of Advanced Photonix. UV enhanced silicon photodiode model 100-13-23-222 was used, and the op amp used Burr Brown's high-voltage, high-current operational amplifier OPA544. The feedback resistor included in the amplifier is 6.1Mohm.
  • the light actuator uses an LED that emits light having a different wavelength for each material to be measured.
  • BSA detection capability is summarized as shown in Figure 5c. As shown in Figure 5c, according to the sensing system according to this embodiment it can be seen that can measure the BSA protein having a concentration of 10 ⁇ 10 3 pM that could not be measured by the sensor according to the prior art.
  • NADH Nicotinamide Adenine Dinucleotide
  • NADH has a maximum absorption wavelength of 260 nm, which is the same as DNA because nucleotides are the basic skeleton. Since the wavelength of 340 nm absorbs only NADH well, the activity of dehydratase can be measured using a 340 nm LED. In the present experimental example, NADH was measured using 270, 280, and 340 nm LEDs, and the current-voltage characteristics for the wavelengths were as shown in FIGS. 6A, 6B, and 6C, respectively. In addition, based on the above measurement results NADH measurement capability is summarized as shown in Figure 6d. As shown in Figure 6d, it was confirmed that the NADH up to 10nM can be measured using the sensing system according to the present embodiment.
  • Graphene oxide (Graphene Oxide) concentration of one of the toxic substances in water was measured, and the current-voltage characteristic curve of the measurement result is shown in FIG. 7.
  • the detection can be up to 4ng / ml concentration
  • using a spectrometer according to the prior art spectrometer
  • the concentration of several ug / ml bar this embodiment It can be seen that the performance of the sensing system is superior.
  • Turbidity was measured using 880 nm, 405 nm, and 280 nm infrared LEDs, respectively, in order to check whether the suspended matter in water could be detected.
  • 8A, 8B, and 8C are enlarged views of snapback sections for respective wavelengths
  • FIG. 8D is a diagram illustrating measurement limits using a sensing system according to an exemplary embodiment of the present invention. As shown in Figure 8a it can be seen that the measurement can be measured to the most accurate and low concentration in the 880nm wavelength band. Examining the detection limits based on the above measurement results it can be seen that can detect up to 0.01NTU as shown in Figure 8d.
  • optical actuator 200 medium containing the detection target material

Abstract

A sensing system, according to the present embodiment, comprises: an optical actuator for applying an optical stimulation to a material to be detected; a photo-detector for outputting an electrical signal having a snapback form in correspondence with an optical reaction formed according to the density of the material to be detected to which the optical stimulation has been applied; an amplifier for amplifying the electrical signal outputted from the photo-detector and positively feeding back and applying the amplified electrical signal to the optical actuator; and a detection unit for detecting the material to be detected by receiving the electrical signal.

Description

포지티브 피드백을 이용한 수질 센서Water quality sensor with positive feedback
본 발명은 포지티브 피드백을 이용한 수질 센서에 관한 것이다.The present invention relates to a water quality sensor using positive feedback.
종래 액츄에이터(actuator)와 센서(sensor)를 사용하는 수질 센싱 시스템은 액츄에이터에서 발생하는 입력 신호의 크기를 일정하게 유지하여, 센서는 액추에이터에 의하여 형성되는 매질의 변화를 검출하였다. 종래 기술에 의한 센싱 시스템은 액츄에이터, 매질 및 센서를 단일단으로 형성하거나, 또는 보다 안정적인 구성을 위하여 네거티브 피드백(negative feedback) 형태로 센싱 시스템을 형성하였다.The conventional water quality sensing system using an actuator and a sensor maintains a constant magnitude of an input signal generated from the actuator, so that the sensor detects a change in the medium formed by the actuator. Sensing systems according to the prior art form actuators, media and sensors in a single stage, or form a sensing system in the form of negative feedback for a more stable configuration.
일 예로, 탁도 센서의 경우 농도를 측정하고자 하는 물질을 포함하는 매질에 액츄에이터가 일정한 광을 조사하면, 센서는 매질을 투과한 광을 센싱하고, 광을 전기적 신호로 변환하여 매질에 포함된 물질의 농도를 측정하였다.For example, in the case of a turbidity sensor, when the actuator irradiates a constant light to a medium containing a material to measure the concentration, the sensor senses the light transmitted through the medium, and converts the light into an electrical signal to determine the material contained in the medium. The concentration was measured.
종래의 센싱 시스템은 제한된 검출한계(LOD, Limit Of Detection)를 가진다. 일 예로, 수질 센서로 사용하는 경우에 센싱 시스템의 검출한계 특성이 높아 물에 검출하고자 하는 물질이 검출한계 이하로 미량 포함된 경우에도 해당 물질이 포함되지 않은 것으로 파악할 수 밖에 없었다.Conventional sensing systems have a limit of detection (LOD). For example, when the sensor is used as a water quality sensor, the detection limit characteristic of the sensing system is high, and even if a small amount of a substance to be detected is included in the water below the detection limit, it was determined that the substance was not included.
본 발명은 상술한 종래 기술에 의한 센싱 시스템의 문제점을 해소하기 위한 것으로, 보다 향상된 검출 한계 특성을 가져서 보다 미량의 물질이 포함되어도 보다 높은 민감도로 검출할 수 있는 센싱 시스템을 제공하는 것이 본 발명의 목적 중 하나이다.The present invention is to solve the problems of the sensing system according to the prior art described above, and to provide a sensing system that can detect with a higher sensitivity even if a smaller amount of substances are included with improved detection limit characteristics of the present invention. One of the purposes.
본 실시예에 따른 센싱 시스템은, 검출 물질에 광학적 자극을 인가하는 광학적 액츄에이터(optical actuator)와, 광학적 자극이 인가된 검출 물질의 농도에 따라 형성되는 광학적 반응에 상응하여 스냅백(snapback) 형태를 가지는 전기적 신호를 출력하는 광 검출기(photo-detector)와, 광 검출기가 출력하는 전기적 신호를 증폭하고, 증폭된 전기적 신호를 광학적 액츄에이터에 포지티브 피드백(positive feedback)하여 인가하는 증폭기(amplifier) 및 전기적 신호를 인가받아 검출 물질을 검출하는 검출부를 포함한다.The sensing system according to the present embodiment has a snapback shape corresponding to an optical actuator that applies an optical stimulus to a detection material and an optical response formed according to the concentration of the detection material to which the optical stimulus is applied. Photo-detector for outputting an electrical signal, an amplifier and electrical signal for amplifying the electrical signal output from the photodetector, and positively applying the amplified electrical signal to an optical actuator. It includes a detection unit for detecting the detection substance is applied.
본 실시예에 의한 센싱 시스템에 의하면 종래의 센서로 검출할 수 없었던 정도로 낮은 농도의 검출 대상 물질을 검출할 수 있다는 장점이 제공된다. The sensing system according to the present embodiment provides an advantage of detecting a substance to be detected at a concentration low enough to be detected by a conventional sensor.
도 1은 본 발명의 실시예에 의한 센싱 시스템의 개요를 도시한 블록도(block diagram)이다. 1 is a block diagram illustrating an overview of a sensing system according to an embodiment of the present invention.
도 2는 본 발명의 실시예에 의한 센싱 시스템의 회로도이다.2 is a circuit diagram of a sensing system according to an embodiment of the present invention.
도 3은 본 실시예에 의한 센싱 시스템으로 검출 물질인 BSA(Bovine Serum Albumin)을 검출할 때 광 검출기가 출력하는 전기적 신호의 전류-전압 특성 곡선이다. 3 is a current-voltage characteristic curve of an electrical signal output by a photo detector when detecting a BSA (Bovine Serum Albumin) which is a detection material by the sensing system according to the present embodiment.
도 4는 스냅백 구간에서 검출 대상 물질의 농도별 전류-전압 특성의 측정 결과를 도시한 도면이다. 4 is a diagram illustrating a measurement result of current-voltage characteristics for each concentration of a substance to be detected in a snapback section.
도 5a는 종래 기술에 따른 센서로 측정한 BSA 측정의 결과값을 도시한 도면이고, 도 5b는 본 실시예로 측정한 BSA 측정의 결과값을 도시한 도면이다. 도 5c는 본 실시예에 의한 센싱 시스템의 BSA 검출 능력을 정리한 도면이다.FIG. 5A is a diagram showing a result of BSA measurement measured by a sensor according to the prior art, and FIG. 5B is a diagram showing a result of BSA measurement measured by this embodiment. 5C is a diagram summarizing the BSA detection capability of the sensing system according to the present embodiment.
도 6a 내지 도 6c는 270, 280, 340nm LED를 사용하여 NADH를 측정한 전류-전압 특성곡선이며, 도 6d는 본 실시예에 의한 센싱 시스템의 NADH측정 능력을 도시한 도면이다.6A to 6C are current-voltage characteristic curves of NADH measured using 270, 280, and 340 nm LEDs, and FIG. 6D is a diagram illustrating NADH measurement capability of the sensing system according to the present embodiment.
도 7은 그라핀 산화물(Graphene Oxide)의 농도를 측정한 결과에 대한 전류-전압 특성 곡선이다.7 is a current-voltage characteristic curve for the result of measuring the concentration of graphene oxide (Graphene Oxide).
도 8a 내지 도 8c는 880nm, 405nm, 280nm 적외선 LED를 각각 사용하여 탁도(turbidity)를 측정하여 얻은 전류-전압 곡선이며, 도 8d는 본 발명의 실시예에 따른 센싱 시스템을 이용한 측정 한계를 도시한 도면이다.8A to 8C are current-voltage curves obtained by measuring turbidity using 880 nm, 405 nm, and 280 nm infrared LEDs, respectively, and FIG. 8D illustrates measurement limits using a sensing system according to an embodiment of the present invention. Drawing.
본 발명에 관한 설명은 구조적 내지 기능적 설명을 위한 실시예에 불과하므로, 본 발명의 권리범위는 본문에 설명된 실시예에 의하여 제한되는 것으로 해석되어서는 아니 된다. 즉, 실시예는 다양한 변경이 가능하고 여러 가지 형태를 가질 수 있으므로 본 발명의 권리범위는 기술적 사상을 실현할 수 있는 균등물들을 포함하는 것으로 이해되어야 한다.Description of the present invention is only an embodiment for structural or functional description, the scope of the present invention should not be construed as limited by the embodiments described in the text. That is, since the embodiments may be variously modified and may have various forms, the scope of the present invention should be understood to include equivalents capable of realizing the technical idea.
한편, 본 출원에서 서술되는 용어의 의미는 다음과 같이 이해되어야 할 것이다.On the other hand, the meaning of the terms described in the present application should be understood as follows.
단수의 표현은 문맥상 명백하게 다르게 뜻하지 않는 한 복수의 표현을 포함하는 것으로 이해되어야 하고, "포함하다" 또는 "가지다" 등의 용어는 설시된 특징, 숫자, 단계, 동작, 구성요소, 부분품 또는 이들을 조합한 것이 존재함을 지정하려는 것이지, 하나 또는 그 이상의 다른 특징들이나 숫자, 단계, 동작, 구성요소, 부분품 또는 이들을 조합한 것들의 존재 또는 부가 가능성을 미리 배제하지 않는 것으로 이해되어야 한다.Singular expressions should be understood to include plural expressions unless the context clearly indicates otherwise, and terms such as "include" or "have" refer to features, numbers, steps, operations, components, parts, or parts thereof described. It is to be understood that the combination is intended to be present, but not to exclude in advance the possibility of the presence or addition of one or more other features or numbers, steps, operations, components, parts or combinations thereof.
본 개시의 실시예들을 설명하기 위하여 참조되는 도면은 설명의 편의 및 이해의 용이를 위하여 의도적으로 크기, 높이, 두께 등이 과장되어 표현되어 있으며, 비율에 따라 확대 또는 축소된 것이 아니다. 또한, 도면에 도시된 어느 구성요소는 의도적으로 축소되어 표현하고, 다른 구성요소는 의도적으로 확대되어 표현될 수 있다.The drawings referred to for describing the embodiments of the present disclosure are intentionally exaggerated in size, height, thickness, etc. for ease of explanation and easy understanding, and are not to be enlarged or reduced in proportion. In addition, any component illustrated in the drawings may be intentionally reduced in size, and other components may be intentionally enlarged in size.
여기서 사용되는 모든 용어들은 다르게 정의되지 않는 한, 본 발명이 속하는 분야에서 통상의 지식을 가진 자에 의해 일반적으로 이해되는 것과 동일한 의미를 가진다. 일반적으로 사용되는 사전에 정의되어 있는 것과 같은 용어들은 관련 기술의 문맥상 가지는 의미와 일치하는 것으로 해석되어야 하며, 본 출원에서 명백하게 정의하지 않는 한 이상적이거나 과도하게 형식적인 의미를 지니는 것으로 해석될 수 없다.All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined. Terms such as those defined in the commonly used dictionaries should be construed to be consistent with the meanings in the context of the related art and should not be construed as having ideal or overly formal meanings unless expressly defined in this application. .
이하에서는 첨부된 도면을 참조하여 본 발명의 실시예를 설명한다. 도 1은 본 발명의 실시예에 의한 센싱 시스템의 개요를 도시한 블록도(block diagram)이며, 도 2는 본 발명의 실시예에 의한 센싱 시스템의 회로도이다. 도 1 및 도 2를 참조하면, 본 실시예에 의한 센싱 시스템은 광학적 액추에이터(optical actuator, 100)를 포함한다. 광학적 액추에이터는 바이어스(bias)를 인가받아 검출물질을 포함하는 매질(200)에 광학적 자극을 인가한다. 이하에서는 자외광, 가시광, 적외광 및 레이저 광을 제공하는 액추에이터를 광학적 액추에이터라고 정의하며, 음파(sonic wave), 초음파(supersonic wave), 자기장(magnetic field), 전기장(electric field) 및 방사능(radioactivity) 등의 비광학적 자극을 인가하는 액추에이터를 비광학적 액추에이터(non-optical actuator)라고 정의한다. 일 예로, 광학적 액추에이터는 바이어스를 인가받아 광을 제공하는 발광 다이오드(LED, Light Emitting Diode), 레이저 다이오드(LD, Laser Diode) 등으로 구현할 수 있다. Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention. 1 is a block diagram illustrating an overview of a sensing system according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a sensing system according to an embodiment of the present invention. 1 and 2, the sensing system according to the present embodiment includes an optical actuator 100. The optical actuator receives a bias to apply an optical stimulus to the medium 200 including the detection material. In the following, actuators providing ultraviolet light, visible light, infrared light and laser light are defined as optical actuators, and sonic wave, supersonic wave, magnetic field, electric field and radioactivity are defined as optical actuators. An actuator that applies a non-optical stimulus such as) is defined as a non-optical actuator. For example, the optical actuator may be implemented as a light emitting diode (LED), a laser diode (LD), or the like which provides light by applying a bias.
발광 다이오드는 가시광, 자외광 또는 적외광 파장 대역의 광을 조사할 수 있으며, 레이저 다이오드는 270nm 내지 3330nm 대역 중 특정 대역을 가지는 레이저 광을 조사할 수 있다. 센싱 시스템으로 검출하고자 하는 물질의 특성에 따라 적합한 대역을 가지는 광을 조사하도록 광학적 액추에이터를 구비하는 것이 바람직하다.The light emitting diode may emit light in the visible, ultraviolet or infrared wavelength band, and the laser diode may emit laser light having a specific band among the 270 nm to 3330 nm bands. It is desirable to have an optical actuator to irradiate light having a suitable band depending on the properties of the material to be detected by the sensing system.
매질(200)은 본 실시예에 의한 센싱 시스템으로 검출하고자 하는 검출 대상 물질을 포함한다. 검출 대상 물질은 광학적 액추에이터로부터 광학적 자극을 인가받아 광학적 반응을 형성한다. 광학적 자극에 대하여 검출 대상 물질이 생성하는 광학적 반응은 일 예로, 광학적 자극에 의한 광이 매질을 투과한 광이거나, 매질에 반사된 광이거나, 매질에 산란된 광이거나 또는 광학적 자극에 의하여 형성된 형광일 수 있다. 이러한 광학적 반응의 일 예로, BSA(Bovine Serum Albumin)는 270~280nm의 광을 흡수하는 특징을 가진다. 따라서 BSA를 포함하는 매질에 275nm 파장을 가지는 레이저를 조사하면 BSA는 인가된 광학적 자극에 대하여 인가된 광을 흡수하는 광학적 반응을 한다. 다만, 이는 단순히 설명을 위한 예일 따름으로, 검출물질과 검출물질에 인가하는 광학적 자극 및 검출물질에 따라 발생하는 광학적 자극에 대한 광학적 반응은 상이할 수 있다. The medium 200 includes a substance to be detected by the sensing system according to the present embodiment. The object to be detected receives an optical stimulus from the optical actuator to form an optical response. The optical response generated by the detection target material to the optical stimulus may be, for example, light from the optical stimulus, light reflected through the medium, light scattered from the medium, or fluorescence formed by the optical stimulus. Can be. As an example of such an optical reaction, BSA (Bovine Serum Albumin) has a feature of absorbing light of 270 ~ 280nm. Therefore, when a laser having a wavelength of 275 nm is irradiated to a medium including BSA, the BSA reacts to the applied optical stimulus to absorb the applied light. However, this is merely an example for explanation, and the optical response to the optical stimulus generated by the detection material and the optical stimulus applied to the detection material and the detection material may be different.
광 검출기(photo detector, 300)는 매질(200)에 광학적 자극이 인가되어 발생하는 광학적 반응을 검출하여 전기적 신호로 출력한다. 일 예로, 광학적 액추에 이터가 인가하는 광학적 자극에 대하여 검출 대상 물질이 생성하는 매질을 투과한 광, 매질에 반사된 광, 매질에 산란된 광 또는 광학적 자극에 의하여 매질이 형성하는 형광 중 어느 하나 이상을 검출하여 전기적 신호를 출력한다. 매질(200)에 포함된 검출물질의 농도에 따라 광학적 반응이 달라질 수 있으며, 그에 따라 광 검출기가 제공하는 전기적 신호도 달라질 수 있다. 일 실시예로, 포토 다이오드(photo diode)로 광검출기를 구현할 수 있으며, 포토 다이오드는 매질이 발생하는 광학적 반응으로 인한 광의 변화를 검출하고, 그에 상응하는 전류를 제공한다.The photo detector 300 detects an optical response generated by applying an optical stimulus to the medium 200 and outputs an optical signal. For example, the optical stimulus applied by the optical actuator is any one of light transmitted through the medium generated by the detection target material, light reflected on the medium, light scattered on the medium, or fluorescence formed by the optical stimulus. The abnormality is detected and an electrical signal is output. The optical response may vary according to the concentration of the detection material included in the medium 200, and accordingly, an electrical signal provided by the photo detector may also vary. In one embodiment, a photodetector may be implemented with a photo diode, which detects a change in light due to the optical response in which the medium occurs and provides a corresponding current.
일 실시예로, 광 검출기(300)는 바이어스 전류를 제공하는 전원(PD bias)로부터 구동 전류(ipd)를 제공받을 수 있으며, 본 실시예에 의한 센싱 시스템은 전원(PD bias)이 제공하는 구동 전류를 변화(sweep)시키면서 매질이 제공하는 광학적 반응을 검출한다. 후술할 바와 같이, 구동 전류가 변화함에 따라 광 검출기(300)는 스냅백 형태를 가지는 전기적 신호를 출력한다.In an embodiment, the photo detector 300 may receive a driving current i pd from a PD bias for providing a bias current, and the sensing system according to the present embodiment may provide a PD current. The optical response provided by the medium is detected while sweeping the drive current. As will be described later, as the driving current changes, the photo detector 300 outputs an electrical signal having a snapback shape.
증폭기(400)는 광 검출기가 제공한 전기적 신호를 증폭하여 출력하며, 증폭된 전기적 신호는 액추에이터의 바이어스(bias)와 부가되어 액추에이터로 피드백된다. 따라서, 액추에이터(100), 매질(200), 광 검출기(300) 및 증폭기(400)는 포지티브 피드백 경로(positive feedback path)를 형성한다. 일 실시예로, 증폭기(400)는 포토 다이오드가 제공한 전류를 전압 신호 형태로 변환하는 전류-전압 컨버터(i-v converter)로 구현할 수 있으며, 전류-전압 컨버터 회로의 출력 전압은 광학적 액추에이터의 바이어스(ACT bias)와 함께 포지티브 피드백된다.The amplifier 400 amplifies and outputs an electrical signal provided by the photo detector, and the amplified electrical signal is added to a bias of the actuator and fed back to the actuator. Thus, the actuator 100, the medium 200, the photo detector 300 and the amplifier 400 form a positive feedback path. In one embodiment, the amplifier 400 may be implemented as a current-to-voltage converter (iv converter) for converting the current provided by the photodiode in the form of a voltage signal, the output voltage of the current-voltage converter circuit is the bias of the optical actuator ( Positive feedback with ACT bias.
도 2에서, 광 검출기(300)가 제공하는 전류(ipd)는 증폭기(400)에 의하여 전압 신호(vfb)로 변환된다. 전압 신호(vfb)는 음전위를 가지므로, 기준 전위가 연결된 광학적 액추에이터(100)의 일단의 전위에 비하여 증폭기(400)와 연결된 타단의 전위가 더 낮아진다. 따라서, 증폭기의 전압(vfb)의 크기가 증가함에 따라 광학적 액추에이터(100)에 인가되는 바이어스는 커지므로 더 큰 광학적 자극을 인가하고, 그에 따라 매질(200)은 인가된 광학적 자극에 대하여 광학적으로 반응하며, 광학적 반응을 검출한 광 검출기(300)는 더 큰 전류(ipd)를 제공한다. 즉, 본 실시예에 의한 센싱 시스템은 포지티브 피드백 경로로 구성되어 있음을 알 수 있다. In FIG. 2, the current i pd provided by the photo detector 300 is converted into a voltage signal v fb by the amplifier 400. Since the voltage signal v fb has a negative potential, the potential of the other end connected to the amplifier 400 is lower than the potential of one end of the optical actuator 100 to which the reference potential is connected. Therefore, as the magnitude of the voltage of the amplifier v fb increases, the bias applied to the optical actuator 100 increases, thereby applying a larger optical stimulus, so that the medium 200 is optically applied to the applied optical stimulus. In response, the photo detector 300 that detects the optical response provides a larger current i pd . That is, it can be seen that the sensing system according to the present embodiment is configured with a positive feedback path.
검출부(500)는 광 검출기(300)가 출력한 전기적 신호를 제공받아 전기적 신호를 분석하여 매질(200) 내에 포함된 검출 대상 물질의 농도를 검출한다. 일 실시예로, 검출부(500)는 리드-아웃 회로를 구비하여 광 검출기가 제공하는 전기적 신호(OUTPUT)를 분석하여 검출 대상 물질의 농도를 검출한다.The detector 500 receives the electrical signal output from the photo detector 300 and analyzes the electrical signal to detect the concentration of the detection target material included in the medium 200. In one embodiment, the detector 500 includes a read-out circuit to detect the concentration of the detection target material by analyzing the electrical signal OUTPUT provided by the photo detector.
도 3은 본 실시예에 의한 센싱 시스템으로 검출 물질인 BSA(Bovine Serum Albumin)을 검출할 때 광 검출기(300)가 출력하는 전기적 신호의 전류-전압 특성 곡선이다. 수직축은 도 1 및 도 2의 광 검출기(300)에 인가되는 바이어스 전류(PD bias, ipd)의 값이며, 수평축은 광 검출기(300) 양단에 형성되는 전압값(vpd)이다. 3 is a current-voltage characteristic curve of an electrical signal output by the photo detector 300 when detecting a BSA (Bovine Serum Albumin) as a sensing material by the sensing system according to the present embodiment. The vertical axis is a value of a bias current (PD bias, i pd ) applied to the photo detector 300 of FIGS. 1 and 2, and the horizontal axis is a voltage value (v pd ) formed across the photo detector 300.
도 1 내지 도 3을 참조하여 광 검출기에 제공되는 바이어스 전류를 0에서 증가시키면서 광 검출기 양단의 전압의 변화를 설명하도록 한다. 광 검출기(300)에 제공되는 바이어스 전류(ipd)를 증가시키면 광 검출기 양단에 형성되는 전압(vpd)도 그에 상응하여 증가하며, 아직 광 액추에이터(100)는 턴 온(turn on)되지 않는다. 1 to 3, the change in voltage across the photodetector will be described while increasing the bias current provided to the photodetector from zero. Increasing the bias current i pd provided to the photo detector 300 correspondingly increases the voltage v pd formed across the photo detector, and the optical actuator 100 is not yet turned on. .
광 검출기에 인가되는 전류가 증가함에 따라 증폭기가 광 액추에이터에 턴 온 전압 이상의 전압을 인가하여 광 액추에이터를 턴 온 시킨다. 턴 온된 광 액추에이터는 매질(200)에 광학적 자극을 인가하며, 매질이 광학적 반응으로 광을 제공하는 경우에, 광 검출기는 이러한 광을 검출하여 전류로 변화하여 출력한다. 광 액추에이터가 턴 온되는 시점에서, 광 검출기가 일정한 전류를 흘리기 위해서는 광학적 반응에 의하여 매질이 발광하는 광에 의한 전류를 보상하기 위해 광 검출기 양단의 전압이 줄어들어야 한다. 따라서 전압은 감소하는 방향으로 이동한다. 즉, 전원이 광 검출기에 인가하는 전류값을 증가시켜도 광 검출기 양단에 인가되는 전압은 오히려 감소하는 음 저항(negative resistance)의 특징을 가진다. As the current applied to the photodetector increases, the amplifier turns on the optical actuator by applying a voltage higher than the turn-on voltage to the optical actuator. The turned on optical actuator applies an optical stimulus to the medium 200, and when the medium provides light in an optical response, the photo detector detects this light and converts it into a current to output it. When the light actuator is turned on, in order for the light detector to flow a constant current, the voltage across the light detector must be reduced to compensate for the current caused by the light emitted by the medium by the optical reaction. Thus, the voltage moves in a decreasing direction. That is, even if the power source increases the current value applied to the photodetector, the voltage applied across the photodetector is rather reduced in negative resistance.
이와 같이 광 검출기로 인가되는 전류가 증가함에 따라 광 검출기 양단 전압이 감소하는 현상을 스냅백 현상이라 하고, 스냅백 현상이 일어나는 시작점을 스냅백 포인트(SB point), 스냅백 현상에 의하여 전류가 증가하여도 전압이 감소하는 구간을 스냅백 구간이라고 한다. The phenomenon that the voltage across the photodetector decreases as the current applied to the photodetector increases is called a snapback phenomenon, and the starting point at which the snapback phenomenon occurs is a snapback point (SB point) and the current increases due to the snapback phenomenon. Even when the voltage decreases is called a snapback period.
광 검출기의 바이어스 전류를 더욱 증가시키면 광 검출기 양단의 전압이 0에 근접하는 정도로 감소한다. 이때를 포화 포인트(SAT point, saturation point)이라 하고, 포화 포인트 이후를 포화 구간이라 한다. Increasing the bias current of the photodetector further reduces the voltage across the photodetector to near zero. This is called a saturation point (SAT point, saturation point), and after the saturation point is called a saturation interval.
포화는 광 검출기의 바이어스 전류가 증가함에 따라 포지티브 피드백에 의하여 결과적으로 더 큰 광학적 자극을 받은 매질이 더 많은 광학적 반응에 의한 광을 광 검출기에 제공하는데, 광 검출기는 증가한 광에 의하여 형성되는 전류를 보상하기 위하여 그 양단 전압을 감소시켜야 하기 때문에 발생하는 것으로 파악되며, 계속적으로 바이어스 전류를 증가시킴에 따라 광 검출기 양단의 전압은 이 지점 부근에서 유지 되고, 전류를 올려도 전압의 변화가 거의 없다. 다만, 도 3에서 도시된 바와 같이 전압이 수 V 정도로 상승할 수 있으나, 광 검출기 양단 전압을 대략 100V 정도로 확장하여 도시한 도 4를 참조하면, 포화 구간에서 전류 변화량에 대한 전압 변화는 미미한 것을 확인할 수 있다.Saturation results in the photodetector providing light to the photodetector with a greater optical response as a result of the greater feedback caused by the positive feedback as a result of the bias current of the photodetector increasing. It is thought to occur because the voltage across the circuit must be reduced to compensate. As the bias current is continuously increased, the voltage across the photodetector is maintained near this point, and there is little change in the voltage even when the current is increased. However, as shown in FIG. 3, the voltage may increase by several V. However, referring to FIG. 4, in which the voltage across the photodetector is expanded to about 100 V, the voltage change with respect to the amount of current change in the saturation period is insignificant. Can be.
또한, 도 3에서 점선으로 도시된 곡선은 포지티브 피드백 경로없이 개방 루프로 신호 경로가 이루어진 상태에서 얻어진 전류-전압 특성 곡선이다. 점선으로 도시된 곡선과 대비하여 보면, 광학적 액추에이터, 매질, 광 검출기 및 증폭기가 포지티브 피드백 하도록 연결되어 있어 스냅백 특성을 보이는 것을 확인할 수 있다.3 is a current-voltage characteristic curve obtained with a signal path in an open loop without a positive feedback path. In contrast to the curve shown by the dashed line, it can be seen that the optical actuator, medium, photodetector and amplifier are connected for positive feedback and exhibit snapback characteristics.
도 4는 스냅백 구간에서 검출 대상 물질의 농도별 전류-전압 특성의 측정 결과를 도시한 도면으로, 탈이온수(DeIonized water, DI)에 검출 대상 물질인 BSA를 각각 1ng, 10ng, ..., 1mg을 첨가한 매질에 대하여 본 실시예에 의한 센싱 시스템으로 검출하여 얻은 전류-전압 곡선이다. 도시된 바와 같이, 광 검출기에 대략 2.1uA 내지 2.15uA의 전류를 인가하면 스냅백 현상이 발생하고, 2.17uA 내지 2.21uA의 전류에서 대략 0V의 전압으로 포화되는 것을 확인할 수 있다. FIG. 4 is a diagram illustrating a measurement result of current-voltage characteristics of concentrations of a substance to be detected in a snapback section, wherein 1 B, 10 ng, of BSA, which is a substance to be detected in deionized water (DI), ..., The current-voltage curve obtained by the sensing system according to the present example was obtained for the medium to which 1 mg was added. As shown, when a current of approximately 2.1uA to 2.15uA is applied to the photo detector, a snapback phenomenon occurs, and it can be seen that the voltage is saturated to a voltage of approximately 0V at a current of 2.17uA to 2.21uA.
검출 대상 물질의 농도에 따라 스냅백 구간에서의 전류 전압 특성이 변화하는 것을 알 수 있다. 따라서, 검출부(500)는 광 검출기 바이어스 전류를 고정하고 광 검출기 양단 전압을 읽거나, 광 검출기 양단 전압을 고정한 후, 광 검출기 바이어스 전류의 값을 읽어서 검출 대상 물질의 농도를 파악할 수 있다. 일 예로, 검출부는 광 검출기 바이어스 전류를 2.15uA로 고정한 후, 광 검출기 양단의 전압이 66V로 읽히면 검출 대상 물질의 농도를 1ng으로 파악할 수 있다. 다른 예로, 검출부는 광 검출기 양단 전압을 40V로 고정한 후, 광 검출기 바이어스 전류가 2.18uA로 읽히면 검출 대상 물질의 농도를 100ng으로 파악할 수 있다. 또한, 스냅백 구간을 지나 포화 포인트에서의 전류, 전압값을 측정하여 검출 대상 물질의 농도를 측정할 수도 있다.It can be seen that the current voltage characteristics in the snapback section change according to the concentration of the substance to be detected. Accordingly, the detector 500 may determine the concentration of the detection target material by fixing the photodetector bias current and reading the voltage across the photodetector, or after fixing the voltage across the photodetector, by reading the value of the photodetector bias current. As an example, the detector may fix the photodetector bias current to 2.15uA, and then, when the voltage across the photodetector is read at 66V, the concentration of the detection target material may be 1 ng. As another example, the detector may fix the voltage across the photodetector to 40V, and then, when the photodetector bias current is read as 2.18 uA, determine the concentration of the detection target material as 100 ng. In addition, the concentration of the substance to be detected may be measured by measuring current and voltage values at the saturation point through the snapback period.
구현예 및 실험결과Embodiment and Experiment Results
이하에서는, 본 발명의 실시예에 의한 센싱 시스템의 구현예와 구현예를 이용하여 검출 대상 물질을 검출한 결과를 설명하도록 한다. 도 2는 본 실시예에 의한 센싱 시스템 구현예의 회로도로, 광 검출기(300)에 바이어스 전류를 인가하는 전원은 애질런트사(Agilent)의 모델 4156이며, 광 검출기로는 어드밴스드 포토닉스(Advanced Photonix) 사의 자외선 증강 포토 다이오드(UV Enhanced Silicon Photodiode) 모델 100-13-23-222를 사용하였고, 연산 증폭기는 버브라운(Burr Brown)사의 고전압 고전류용 연산 증폭기 OPA544를 사용하였다. 증폭기에 포함된 피드백 저항은 6.1Mohm 이다. 광 액추에이터는 측정하고자 하는 검출 대상 물질별로 상이한 파장의 광을 방출하는 LED를 사용하였다. Hereinafter, a result of detecting a substance to be detected using an embodiment and implementation of a sensing system according to an embodiment of the present invention will be described. 2 is a circuit diagram of a sensing system implementation according to the present embodiment, wherein a power supply for applying a bias current to the photodetector 300 is Agilent's Model 4156, and the photodetector is an ultraviolet light of Advanced Photonix. UV enhanced silicon photodiode model 100-13-23-222 was used, and the op amp used Burr Brown's high-voltage, high-current operational amplifier OPA544. The feedback resistor included in the amplifier is 6.1Mohm. The light actuator uses an LED that emits light having a different wavelength for each material to be measured.
물 속의 단백질 검출 가능성을 테스트하기 위하여 10pM에서 100uM까지의 서로 다른 농도를 가지는 BSA를 측정하였다. 종래 기술에 따른 센서로 측정한 결과값은 도 5a와 같으며, 본 실시예로 측정한 결과 값은 도 5b와 같다. 위에서 설명한 바와 같이 포지티브 피드백에 의하여 스냅백 현상이 발생하는 것을 확인할 수 있다. 또한, 위 측정 결과를 토대로 BSA 검출 능력을 정리하면 도 5c과 같다. 도 5c에서 도시된 바와 같이, 본 실시예에 의한 센싱 시스템에 의하면 종래 기술에 의한 센서로 측정할 수 없었던 10~ 103pM 농도를 가지는 BSA 단백질을 측정할 수 있음을 확인할 수 있다.To test the detectability of proteins in water, BSAs with different concentrations ranging from 10 pM to 100 uM were measured. The result value measured by the sensor according to the prior art is shown in Figure 5a, the result value measured in this embodiment is shown in Figure 5b. As described above, it can be seen that a snapback phenomenon occurs due to positive feedback. In addition, based on the above measurement results BSA detection capability is summarized as shown in Figure 5c. As shown in Figure 5c, according to the sensing system according to this embodiment it can be seen that can measure the BSA protein having a concentration of 10 ~ 10 3 pM that could not be measured by the sensor according to the prior art.
수중 미생물의 존재를 검출하기 위하여 NADH의 농도를 측정하였다. Nicotinamide Adenine Dinucleotide (NAD)는 세포에서 발견되는 중요한 조효소로, NADH는 NAD의 환원 형태이고, 세포 대사 과정에서 아래와 같은 반응 식을 따라 발생하는 물질이다.The concentration of NADH was measured to detect the presence of microorganisms in water. Nicotinamide Adenine Dinucleotide (NAD) is an important coenzyme found in cells. NADH is a reduced form of NAD, and it occurs in the cell metabolism according to the following equation.
NAD+ + 환원 물질 (2e- + 2H+ ) ⇔ NADH + H+ + 산화물질NAD + + reducing substance (2e- + 2H +) ⇔ NADH + H + + oxide
따라서 NADH의 존재 여부를 측정하면 물 속의 미생물이 존재하는지 확인할 수 있다. NADH는 뉴클레오타이드가 기본 골격이기 때문에 흡수 극대파장이 260nm로 DNA와 같다. 340nm의 파장은 NADH만이 잘 흡수하기 때문에, 탈수조효소의 활성도를 340nm LED를 사용하여 측정할 수 있다. 본 실험예에서는 NADH를 270, 280, 340nm LED를 사용하여 측정하였고, 각각 파장에 대한 전류-전압 특성은 각각 도 6a, 6b 및 6c와 같다. 또한, 위 측정 결과를 토대로 NADH측정 능력을 정리하면 도 6d와 같다. 도 6d에 도시된 바와 같이, 본 실시예에 의한 센싱 시스템을 이용하면 10nM까지의 NADH를 측정할 수 있음을 확인하였다.Therefore, measuring the presence of NADH can determine whether the presence of microorganisms in the water. NADH has a maximum absorption wavelength of 260 nm, which is the same as DNA because nucleotides are the basic skeleton. Since the wavelength of 340 nm absorbs only NADH well, the activity of dehydratase can be measured using a 340 nm LED. In the present experimental example, NADH was measured using 270, 280, and 340 nm LEDs, and the current-voltage characteristics for the wavelengths were as shown in FIGS. 6A, 6B, and 6C, respectively. In addition, based on the above measurement results NADH measurement capability is summarized as shown in Figure 6d. As shown in Figure 6d, it was confirmed that the NADH up to 10nM can be measured using the sensing system according to the present embodiment.
수중 독성 물질 중 하나인 그라핀 산화물(Graphene Oxide)의 농도를 측정하였으며, 그 측정 결과에 대한 전류-전압 특성 곡선은 도 7과 같다. 도 7에서 확인할 수 있는 바와 같이 4ng/ml 농도까지 검출이 가능함을 알 수 있으며, 종래의 기술에 의한 스펙트로미터(spectrometer)를 사용하면 수 ug/ml대의 농도를 측정할 수 있는 바, 본 실시예에 의한 센싱 시스템의 성능이 우월함을 확인할 수 있다.Graphene oxide (Graphene Oxide) concentration of one of the toxic substances in water was measured, and the current-voltage characteristic curve of the measurement result is shown in FIG. 7. As can be seen in Figure 7 it can be seen that the detection can be up to 4ng / ml concentration, using a spectrometer according to the prior art (spectrometer) can measure the concentration of several ug / ml bar, this embodiment It can be seen that the performance of the sensing system is superior.
물 속 부유물을 검출할 수 있는지 확인하기 위하여 880nm, 405nm, 280nm 적외선 LED를 각각 사용하여 탁도(turbidity)를 측정하였다. 도 8a, 도 8b 및 도 8c는 각 파장별 스냅백 구간을 확대하여 도시한 도면이며, 도 8d는 본 발명의 실시예에 따른 센싱 시스템을 이용한 측정 한계를 도시한 도면이다. 도 8a에 도시된 바와 같이 880nm 파장대에서 가장 정밀하고 낮은 농도까지 측정을 할 수 있음을 확인할 수 있다. 위의 측정 결과를 토대로 검출 한계를 검토하면 도 8d에 도시된 바와 같이 0.01NTU까지 검출할 수 있는 것을 확인할 수 있다.Turbidity was measured using 880 nm, 405 nm, and 280 nm infrared LEDs, respectively, in order to check whether the suspended matter in water could be detected. 8A, 8B, and 8C are enlarged views of snapback sections for respective wavelengths, and FIG. 8D is a diagram illustrating measurement limits using a sensing system according to an exemplary embodiment of the present invention. As shown in Figure 8a it can be seen that the measurement can be measured to the most accurate and low concentration in the 880nm wavelength band. Examining the detection limits based on the above measurement results it can be seen that can detect up to 0.01NTU as shown in Figure 8d.
본 발명에 대한 이해를 돕기 위하여 도면에 도시된 실시 예를 참고로 설명되었으나, 이는 실시를 위한 실시예로, 예시적인 것에 불과하며, 당해 분야에서 통상적 지식을 가진 자라면 이로부터 다양한 변형 및 균등한 타 실시 예가 가능하다는 점을 이해할 것이다. 따라서, 본 발명의 진정한 기술적 보호범위는 첨부된 특허청구범위에 의해 정해져야 할 것이다.Although described with reference to the embodiments shown in the drawings to aid the understanding of the present invention, this is an embodiment for the implementation, it is merely exemplary, those skilled in the art from various modifications and equivalents therefrom It will be appreciated that other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the appended claims.
[부호의 설명][Description of the code]
100: 광학적 액츄에이터 200: 검출 대상 물질을 포함한 매질100: optical actuator 200: medium containing the detection target material
300: 광 검출기 400: 증폭기300: light detector 400: amplifier
500: 검출부      500: detector

Claims (20)

  1. 센싱 시스템에 있어서, In the sensing system,
    검출 물질에 광학적 자극을 인가하는 광학적 액츄에이터(optical actuator);An optical actuator for applying an optical stimulus to the detection material;
    상기 광학적 자극이 인가된 검출 물질의 농도에 따라 형성되는 광학적 반응에 상응하여 스냅백(snapback) 형태를 가지는 전기적 신호를 출력하는 광 검출기(photo-detector); A photo-detector for outputting an electrical signal having a snapback shape corresponding to the optical response formed according to the concentration of the detection material to which the optical stimulus is applied;
    상기 광 검출기가 출력하는 상기 전기적 신호를 증폭하고, 증폭된 상기 전기적 신호를 상기 광학적 액츄에이터에 포지티브 피드백(positive feedback)하여 인가하는 증폭기(amplifier); 및An amplifier for amplifying the electrical signal output by the photo detector and applying the amplified electrical signal to the optical actuator by positive feedback; And
    상기 전기적 신호를 인가받아 상기 검출 물질을 검출하는 검출부를 포함하는 센싱 시스템.And a detector configured to receive the electrical signal and detect the detection substance.
  2. 제1항에 있어서, The method of claim 1,
    상기 센싱 시스템은 상기 광 검출기에 바이어스 전류를 인가하는 전원을 더 포함하는 센싱 시스템.The sensing system further comprises a power supply for applying a bias current to the photo detector.
  3. 제1항에 있어서, The method of claim 1,
    상기 광학적 액츄에이터는 발광 다이오드(LED, Light Emitting Diode), 레이저 다이오드(LD, Laser Diode) 중 어느 하나를 포함하는 센싱 시스템.The optical actuator includes one of a light emitting diode (LED) and a laser diode (LD).
  4. 제1항에 있어서, The method of claim 1,
    상기 광 검출기는 광 다이오드(photo-diode)를 포함하는 센싱 시스템.The photo detector includes a photo-diode.
  5. 제1항에 있어서, The method of claim 1,
    상기 광 검출기는 상기 광학적 액츄에이터가 인가한 상기 광학적 자극이 상기 검출 물질에 조사되어 형성된 반사광, 투과광, 산란광 및 형광 중 어느 하나 이상을 검출하여 그에 상응하는 상기 전기적 신호를 출력하는 센싱 시스템. And the photo detector detects at least one of reflected light, transmitted light, scattered light, and fluorescence formed by the optical stimulus applied by the optical actuator to the detection material, and outputs the electrical signal corresponding thereto.
  6. 제1항에 있어서, The method of claim 1,
    상기 증폭기는 전류 신호를 인가받아 그에 상응하는 전압 신호로 변환하여 출력하는 전류-전압 변환 증폭기인 센싱 시스템.And the amplifier is a current-voltage conversion amplifier that receives a current signal and converts it into a corresponding voltage signal.
  7. 제1항에 있어서, The method of claim 1,
    상기 스냅백 형태를 가지는 전기적 신호는, The electrical signal having the snapback form,
    스냅백 포인트(smapback point)으로부터 상기 광 검출기 양단 전압이 증가함에 따라 상기 전기적 신호가 감소하는 스냅백 구간과, 상기 광 검출기 양단 전압이 증가함에 따라 상기 전기적 신호가 증가하는 포화 구간을 포함하며, 상기 스냅백 구간과 상기 포화 구간은 포화 포인트(saturation point)를 거쳐 연결되는 센싱 시스템. A snapback section in which the electrical signal decreases as the voltage across the photo detector increases from a snapback point, and a saturation section in which the electrical signal increases as the voltage across the photo detector increases, And a snapback section and the saturation section are connected via a saturation point.
  8. 제7항에 있어서, The method of claim 7, wherein
    상기 검출기는, The detector,
    상기 스냅백 구간에서 상기 광 검출기에 일정한 전류를 제공될 때 상기 광 검출기의 양단 전압을 검출하여 상기 검출 물질의 농도를 검출하는 센싱 시스템.The sensing system detects the concentration of the detection material by detecting a voltage across the photo detector when a constant current is provided to the photo detector in the snapback period.
  9. 제7항에 있어서,The method of claim 7, wherein
    상기 검출기는, The detector,
    상기 스냅백 구간에서 상기 광 검출기에 일정한 전압이 제공될 때 상기 광 검출기로 흐르는 전류를 검출하여 상기 검출 물질의 농도를 검출하는 센싱 시스템.And a concentration of the detection material by detecting a current flowing through the photo detector when a constant voltage is provided to the photo detector in the snapback period.
  10. 제7항에 있어서,The method of claim 7, wherein
    상기 검출기는, The detector,
    상기 포화 포인트에서의 전류, 전압값을 검출하여 상기 검출 물질의 농도를 검출하는 센싱 시스템.A sensing system for detecting the concentration of the detection material by detecting the current, voltage value at the saturation point.
  11. 제7항에 있어서,The method of claim 7, wherein
    상기 검출기는, The detector,
    상기 포화 구간의 전류, 전압의 비를 검출하여 상기 검출 물질의 농도를 검출하는 센싱 시스템.Sensing system for detecting the concentration of the detection material by detecting the ratio of the current, the voltage of the saturation period.
  12. 검출 물질에 광학적 자극을 인가하는 광학적 액츄에이터;An optical actuator for applying an optical stimulus to the detection material;
    바이어스 전류가 인가되며, 상기 검출 물질의 광학적 반응으로 인한 입사 광이 입력되는 광 검출기; 및A photo detector to which a bias current is applied and input incident light due to the optical response of the detection material; And
    상기 바이어스 전류가 증가함에 따라 상기 광학적 액츄에이터의 상기 광학적 자극을 증가시키는 포지티브 피드백 유닛을 포함하는 센싱 시스템. And a positive feedback unit that increases the optical stimulus of the optical actuator as the bias current increases.
  13. 제12항에 있어서, The method of claim 12,
    상기 광학적 액츄에이터는 발광 다이오드(LED, Light Emitting Diode) 및 레이저 다이오드(LD, Laser Diode) 중 적어도 어느 하나를 포함하며, 상기 광 검출기는 광 다이오드(photo-diode)를 포함하는 센싱 시스템The optical actuator includes at least one of a light emitting diode (LED) and a laser diode (LD), and the photo detector includes a sensing system including a photo-diode.
  14. 제13항에 있어서, The method of claim 13,
    상기 포지티브 피드백 유닛은 상기 바이어스 전류가 증가함에 따라 상기 광학적 액츄에이터에 포함된 상기 다이오드의 순방향 전압을 증가시키는 센싱 시스템. And the positive feedback unit increases the forward voltage of the diode included in the optical actuator as the bias current increases.
  15. 제13항에 있어서, The method of claim 13,
    상기 포지티브 피드백 유닛은 차동 증폭기를 포함하며, The positive feedback unit comprises a differential amplifier,
    상기 차동 증폭기의 제1 입력단에는 기준 전압이 인가되고, 상기 차동 증폭기의 제2 입력단에는 상기 바이어스 전류가 입력되고, 상기 제2 입력단과 상기 차동 증폭기의 출력단 사이에는 저항이 연결되고, 상기 출력단은 상기 광학적 액츄에이터에 포함된 상기 다이오드에 연결되는 센싱 시스템. A reference voltage is applied to the first input terminal of the differential amplifier, the bias current is input to the second input terminal of the differential amplifier, a resistor is connected between the second input terminal and the output terminal of the differential amplifier, and the output terminal is the A sensing system coupled to the diode included in the optical actuator.
  16. 제12항에 있어서, The method of claim 12,
    상기 광 검출기는 상기 바이어스 전류 및 상기 입사 광에 대응하는 센싱 전압을 출력하는 센싱 시스템. And the photo detector outputs a sensing voltage corresponding to the bias current and the incident light.
  17. 제16항에 있어서,The method of claim 16,
    상기 광 검출기는 상기 바이어스 전류가 증가함에 따라 상기 센싱 전압이 감소하는 스냅백 구간을 가지는 센싱 시스템.The photo detector has a snap back period in which the sensing voltage decreases as the bias current increases.
  18. 제17항에 있어서, The method of claim 17,
    상기 스냅백 구간에서 소정의 상기 바이어스 전류를 제공하면서 상기 센싱 전압을 측정함으로써 상기 검출 물질의 농도를 측정하는 검출부를 더 포함하는 센싱 시스템. And a detector configured to measure the concentration of the detection material by measuring the sensing voltage while providing the predetermined bias current in the snapback period.
  19. 제12항에 있어서, The method of claim 12,
    상기 입사광은 상기 광학적 자극이 상기 검출 물질에 조사되어 형성된 반사광, 투과광, 산란광 및 형광 중 적어도 어느 하나를 포함하는 센싱 시스템.And the incident light includes at least one of reflected light, transmitted light, scattered light, and fluorescence formed by irradiating the detection material with the optical stimulus.
  20. 제12항에 있어서, The method of claim 12,
    상기 검출 물질은 BSA(Bovine Serum Albumin), NADH(chemically reduced form of NAD(Nicotinamide Adenine Dinucleotide)), 그라핀 산화물(Graphene Oxide) 및 부유물 중 적어도 어느 하나를 포함하는 센싱 시스템.The detection substance includes at least one of Bovine Serum Albumin (BSA), chemically reduced form of Nicotinamide Adenine Dinucleotide (NAD), Graphene Oxide and suspended solids.
PCT/KR2014/010208 2013-10-29 2014-10-28 Water quality sensor using positive feedback WO2015065023A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
DE112014004937.9T DE112014004937B4 (en) 2013-10-29 2014-10-28 Measurement system for detecting a concentration of a target detection substance in a medium
US15/026,506 US10295519B2 (en) 2013-10-29 2014-10-28 Water quality sensor using positive feedback
CN201480059243.0A CN105765366B (en) 2013-10-29 2014-10-28 Use the water quality sensor of positive feedback

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR10-2013-0129131 2013-10-29
KR20130129131 2013-10-29
KR10-2014-0090256 2014-07-17
KR1020140090256A KR101644623B1 (en) 2013-10-29 2014-07-17 Water Quality Sensor Using Positive Feedback

Publications (1)

Publication Number Publication Date
WO2015065023A1 true WO2015065023A1 (en) 2015-05-07

Family

ID=53004543

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2014/010208 WO2015065023A1 (en) 2013-10-29 2014-10-28 Water quality sensor using positive feedback

Country Status (1)

Country Link
WO (1) WO2015065023A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3070456A1 (en) * 2015-03-18 2016-09-21 Giparang Co., Ltd. Sensing system using positive feedback

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7090992B2 (en) * 1997-11-25 2006-08-15 Ut-Battelle, Llc Bioluminescent bioreporter integrated circuit devices and methods for detecting estrogen
KR20060124111A (en) * 2005-05-31 2006-12-05 한국생산기술연구원 Apparatus for measuring exhaust gas using wavelength modulation spectroscopy
KR20090081705A (en) * 2008-01-24 2009-07-29 성균관대학교산학협력단 Optical gas sensor and method for measuring mixed gases
WO2010090391A2 (en) * 2009-02-03 2010-08-12 (주)동양화학 Turbidity-measuring probe having polymer membranes modified by a hydrophobic sol-gel
WO2013032138A2 (en) * 2011-08-26 2013-03-07 한국생산기술연구원 Optical measurement system for gas concentration

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7090992B2 (en) * 1997-11-25 2006-08-15 Ut-Battelle, Llc Bioluminescent bioreporter integrated circuit devices and methods for detecting estrogen
KR20060124111A (en) * 2005-05-31 2006-12-05 한국생산기술연구원 Apparatus for measuring exhaust gas using wavelength modulation spectroscopy
KR20090081705A (en) * 2008-01-24 2009-07-29 성균관대학교산학협력단 Optical gas sensor and method for measuring mixed gases
WO2010090391A2 (en) * 2009-02-03 2010-08-12 (주)동양화학 Turbidity-measuring probe having polymer membranes modified by a hydrophobic sol-gel
WO2013032138A2 (en) * 2011-08-26 2013-03-07 한국생산기술연구원 Optical measurement system for gas concentration

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3070456A1 (en) * 2015-03-18 2016-09-21 Giparang Co., Ltd. Sensing system using positive feedback

Similar Documents

Publication Publication Date Title
Estes et al. Reagentless detection of microorganisms by intrinsic fluorescence
US8357888B2 (en) Photoelectric feedback sensing system having a sensing apparatus outputting a light signal corresponding to a characteristic of a sample within the sensing apparatus
ATE345497T1 (en) OPTOELECTRONIC DETECTION SYSTEM
CN101906384B (en) Instrument and method for bacterium flow count testing
PT103561A (en) SYSTEM OF DETECTION AND QUANTIFICATION OF BIOLOGICAL MATTER CONSTITUTED BY ONE OR MORE OPTICAL SENSORS AND ONE OR MORE LIGHT SOURCES, ASSOCIATED PROCEDURE AND THEIR RESPECTIVE USES
KR20190142916A (en) Apparatus and Method for Detecting Algae
WO2015065023A1 (en) Water quality sensor using positive feedback
KR101663289B1 (en) Water Quality Sensor Using Positive Feedback
Preuschoff et al. Photodiode-based chemiluminometric biosensors for hydrogen peroxide and L-lysine
WO2015065024A1 (en) Sensing system using positive feedback
KR101644623B1 (en) Water Quality Sensor Using Positive Feedback
Kudo et al. NADH-fluorometric biochemical gas sensor (Bio-Sniffer) for evaluation of indoor air quality
CN105806832A (en) Preparation method and application of hydrogen peroxide sensor based on double functions of electrochemiluminescence and photoelectrochemistry
Ye et al. Acetone biosensor based on fluorometry of reduced nicotinamide adenine dinucleotide consumption in reversible reaction by secondary alcohol dehydrogenase
CN105992944B (en) Oxygen sensor comprising a large-diameter optical fibre whose tip is coated
KR102170285B1 (en) Sensor having improved detection capability
CN105823773A (en) Preparation method and applications of bifunctional enzyme-free hydrogen peroxide photoelectric chemical sensor
WO2019054773A1 (en) Sensor having enhanced detection capability
KR20160090560A (en) Photon detecting circuit using photodiode and detecting device with the same
Miyajima et al. Gas-phase biosensor with high sensitive & selective for formaldehyde vapor: Monitoring of residential air quality for indoor public health
CN210571960U (en) Three-mechanism detection system for capillary electrophoresis
Kudo et al. NADH-fluorometric biochemical gas sensor (bio-sniffer) for assessment of indoor air quality
CN105717175A (en) Preparation method and application of hydrogen peroxide sensor based on combination of two electrochemical methods
Yi et al. A multichannel fiber optic photoluminescence system for multiplex biosensor arrays
CN103308503A (en) Separated micro-column coupling light guide fiber exciting light induction fluorescence component

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 14858150

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 15026506

Country of ref document: US

WWE Wipo information: entry into national phase

Ref document number: 112014004937

Country of ref document: DE

Ref document number: 1120140049379

Country of ref document: DE

122 Ep: pct application non-entry in european phase

Ref document number: 14858150

Country of ref document: EP

Kind code of ref document: A1