JP2006058196A - Optical measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical measuring instrument capable of measuring a particle or the like contained in a liquid sample, with high sensitivity. <P>SOLUTION: This measuring instrument is provided with a light source 16, an electric power source 15, a container 11 for holding the liquid sample, diffraction gratings 13a, 13b, 14a, 14b formed in positions contacting with the liquid sample in the container to generate a basic diffraction light pattern by irradiation with light from the light source 16, electrode pairs 13, 14 for constituting at least one part of the diffraction gratings, and capable of impressing negative and positive voltages from the electric power source 15, and a photodetector 18 for detecting diffraction light by the diffraction gratings. A deformed diffraction light pattern different from the basic diffraction light pattern is generated by impressing the voltages to the electrode pairs 13, 14 to change a refractive index distribution of the liquid sample, and information about the liquid sample is measured based on the deformed diffraction light pattern. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical measurement apparatus that optically measures a liquid sample, and more particularly to an optical measurement apparatus that measures a substance present in a liquid from a change in the refractive index of the liquid sample. The optical measurement apparatus of the present invention can be applied to, for example, an apparatus for confirming the presence / absence of particles in a solution, the presence / absence of particles generated by an electrochemical reaction of the solution, and measuring the particle concentration.

  As a measurement method for performing optical measurement without directly irradiating the substance to be measured in the solution with light, the optical waveguide is placed in contact with the part adjacent to the object to be measured, and the equivalent refractive index and optical path length of the optical waveguide. A sensor device technology that indirectly measures the optical characteristics of an object to be measured by measuring the change in the above has been disclosed (see Patent Document 1).

  This sensor device uses two optical waveguides, a standard waveguide (reference side) and a sensing waveguide (sample side). Among these, the sensing waveguide side is measured in two different states, a state in contact with the object to be measured and a state not in contact with the object to be measured, and the influence of the object to be measured existing in the vicinity of the sensing waveguide. Thus, the equivalent refractive index of the transmitted light on the sensing waveguide side is changed. On the other hand, the reference waveguide side is disposed at a position separated from the object to be measured and is not affected by the object to be measured. The refractive index of light transmitted through the standard waveguide is measured for reference (for standard). Then, the light beams that have passed through these two optical waveguides are caused to interfere. At this time, the position of the interference fringe moves between the interference fringe in a state where the sensing waveguide side is in contact with the object to be measured and the interference fringe in a state not in contact with the object to be measured.

  The amount of movement of the interference fringes corresponds to the change in the equivalent refractive index of the sensing waveguide, that is, the change in the concentration or thickness of the measurement object existing around the sensing waveguide that causes the equivalent refractive index change. From the measurement of the amount of movement of the interference fringes, information on the object to be measured can be measured (two-beam interference method).

In addition, in the prior patent application by the applicant himself, as an optical measurement device for measuring the ease of diffusion of particles (solute molecules), the particles in the liquid are moved by causing dielectrophoresis to move the particles. An apparatus has been proposed that evaluates the diffusion of particles from the change in refractive index when the region is formed and then dielectrophoresis is stopped and the particles are diffused from the particle concentration region (Japanese Patent Application No. 2004-204024). . In this optical measuring apparatus, a local refractive index change of the solution is generated by applying a voltage to the solution to be measured through two parallel electrodes to cause dielectrophoresis. As an optical method for detecting a change in refractive index, a method such as a two-beam interference method for measuring the amount of movement of interference fringes is used as in Patent Document 1.
Special table 2003-515126 gazette

In the optical measurement method disclosed in Patent Document 1 described above, only a static refractive index measurement can be performed. For example, the optical measurement is performed after positively moving particles in the sample. It is not possible.

Therefore, an object of the present invention is to provide an optical measuring apparatus capable of performing optical measurement of a liquid sample with high sensitivity after particle movement or particle generation is caused by dielectrophoresis or the like.
Further, in the method of detecting refractive index change by the two-beam interference method as disclosed in Patent Document 1, the amount of movement of the interference fringes is measured. When measuring the amount of movement of interference fringes, the amount of movement is usually calculated after measuring the movement of the bright lines among the bright lines and dark lines forming the interference fringes using an array detector such as a CCD. Arithmetic processing is performed. In this case, since the movement of the peak position of the bright line is measured as well as the necessity for calculation, a minute change in the light amount accompanying the peak movement must be detected, and a highly sensitive measurement is performed. Have difficulty. In other words, the bright line peak position immediately next (the position where the bright line peak moves) is originally a bright place where the amount of light is slightly inferior to the bright line peak position at that time, and the bright line peak position. It is difficult to detect a slight difference in the amount of light when the is moved.

  Rather, it is desirable to be able to detect a peak at a position where the contrast of light and dark is clear, such as when the bright line is moved to a position where the dark line has been present.

  Therefore, the present invention detects the change in the refractive index of the liquid sample not by detecting the amount of movement of the interference fringes but by detecting a signal in a state in which contrast between light and dark is clearly obtained by a new optical measurement method, An object of the present invention is to provide an optical measurement apparatus capable of performing high-precision optical measurement.

  The optical measuring device of the present invention made to solve the above problems is formed at a position in contact with a light source, a power source, a container holding a liquid sample, and the liquid sample in the container, and is irradiated with light from the light source. A diffraction grating that generates a basic diffraction light pattern by forming a pair of electrodes, an electrode pair that can form at least a part of the diffraction grating and that can be applied with positive and negative voltages from a power source, and light that detects diffracted light by the diffraction grating A modified diffracted light pattern different from the basic diffracted light pattern by changing the refractive index distribution of the liquid sample by applying a voltage to the electrode pair, and the liquid sample based on the deformed diffracted light pattern Information about is being measured.

  According to the present invention, light is irradiated from the light source toward the electrode pair constituting the diffraction grating in a state where the liquid sample is placed and held in the container. At this time, light is diffracted by the diffraction grating to generate a diffracted light pattern. The diffracted light pattern at this time becomes the basic diffracted light pattern.

  Subsequently, positive and negative voltages are applied from the power source to the electrode pair. If the refractive index distribution of the liquid sample near the diffraction grating changes due to a chemical change or particle movement caused by the voltage of the liquid sample (or particles in the liquid sample), the basic diffracted light pattern A new derivative grating with a period different from that of the diffraction grating is generated. With this derivative diffraction grating, new diffracted light is generated, and as a result, a modified diffracted light pattern in which new diffracted light is added to the basic diffracted light pattern is generated. In this modified diffracted light pattern, newly added diffracted light is generated at a position (dark portion) where no diffracted light was present in the basic diffracted light pattern. Therefore, by measuring the change from the basic diffracted light pattern to the deformed diffracted light pattern with a photodetector, the dynamic change of the liquid sample (for example, refractive index change due to particle movement) is measured.

  According to the present invention, a derivative diffraction grating having a period different from that of the diffraction grating generating the basic diffraction light pattern due to a change in refractive index generated by applying positive and negative voltages to the electrode pair constituting the diffraction grating. Due to this derivative diffraction grating, a modified diffracted light pattern in which new diffracted light is added to the basic diffracted light pattern is generated. The diffracted light newly added to the deformed diffracted light pattern is generated at the position where the diffracted light did not exist in the basic diffracted light pattern (dark part). The generated diffracted light can be detected, and highly sensitive and highly accurate measurement can be performed.

  In addition, the appearance position of the newly generated diffracted light is determined depending on the period of the derivative diffraction grating, and does not depend on the temperature change of the liquid sample and is always a constant position. The brightness of the diffracted light appearing at the position may be directly measured with a single detector, and the configuration of the detection optical system can be simplified.

  In the above invention, an AC power source may be used as the power source, and by applying an AC voltage to the electrode pair, dielectrophoresis may be caused in the liquid sample to generate a deformed diffracted light pattern.

  When an AC voltage is applied to the electrode pair to induce dielectrophoresis, if particles exist in the liquid sample, the particles will collect in the region where the lines of electric force concentrate near the electrodes due to dielectrophoresis. As a result, the optical characteristics of the liquid sample in the vicinity of the diffraction grating change, so that the diffracted light pattern changes. This diffracted light pattern can be detected with high sensitivity by a photodetector.

  In the above invention, the positive and negative electrode pairs may be arranged so that a portion where the positive electrode and the negative electrode are adjacent is repeated at a cycle which is an integral multiple of twice or more the grating interval cycle of the diffraction grating. Good.

  Since the lines of electric force are concentrated on the portion where the positive electrode and the negative electrode are adjacent to each other, it is a region where the dielectrophoresis and chemical change occur most. When this region is generated with a period that is an integral multiple of twice, three times,... Of the period of the diffraction grating, diffracted light is newly generated between the diffracted lights obtained by the basic diffracted light pattern by the diffraction grating. It will be. Therefore, a change in the liquid sample can be detected with high sensitivity depending on whether or not new diffracted light is generated in addition to the basic diffracted light pattern.

  In the above invention, each electrode constituting the electrode pair is composed of a plurality of linear electrode pieces arranged in parallel and a connection portion for electrically connecting the linear electrode pieces, A linear electrode piece uneven region where at least two linear electrode pieces are adjacent to each other and a linear electrode piece absent region where no linear electrode piece exists are alternately arranged, and the linear electrode piece in one electrode The diffraction grating may be formed such that the linear electrode piece unevenly distributed region of the other electrode overlaps the absent region.

  Thereby, it can arrange | position so that the part which a positive electrode and a negative electrode adjoin may repeat with the period of the integral multiple of 2 times or more of the grating | lattice space | interval period of a diffraction grating.

  In the above invention, each electrode constituting the electrode pair includes a plurality of linear electrode pieces arranged in parallel and a connecting portion for electrically connecting the linear electrode pieces. The linear electrode pieces are not electrically connected to any electrode, and the floating portions made of linear members having substantially the same shape as the linear electrode pieces are regularly arranged. It may be.

  Thereby, it can arrange | position so that the part which a positive electrode and a negative electrode adjoin may repeat with the period of the integral multiple of 2 times or more of the grating | lattice space | interval period of a diffraction grating.

  In the above invention, at least a part of the container is formed of a material that transmits light source light, and an electrode pair is formed on the container part that transmits the light source light, and the light source light is incident on the electrode pair. The photodetector may detect diffracted light transmitted through the liquid sample or diffracted light reflected from the liquid sample.

  Thereby, the transmission diffracted light or the reflected diffracted light can be easily obtained by causing the light source light to enter the electrode pair formed in a part of the container. Here, the container portion that transmits the light source light may be a bottom surface or a side wall surface.

  Further, the electrode pair may be formed of a metal film that causes surface plasmon resonance when irradiated with light source light.

  By using surface plasmon resonance, the intensity of the diffracted light changes greatly with a slight change in the refractive index immediately above the electrode. Thereby, measurement with higher sensitivity can be performed by measuring the diffracted light intensity together with the diffracted light pattern.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments described below, and it goes without saying that various aspects are included without departing from the spirit of the present invention.
(Embodiment 1)
FIG. 1 is a schematic cross-sectional view showing a configuration of an optical measuring apparatus according to an embodiment of the present invention, and FIG. 2 is a top view thereof.

  The optical measurement apparatus according to this embodiment performs optical measurement while performing dielectrophoresis, and is formed on a container 11 that holds a liquid sample and a bottom plate 12a that is a bottom surface of the container 11, and forms a diffraction grating. A pair of electrodes 13, 14, an AC power supply 15 that applies an AC voltage to the electrodes 13 and 14, a light source 16, a lens optical system 17 that converges light source light, and a photodetector 18 that detects diffracted light. Become.

  The container 11 is formed by sticking a frame body 12b serving as a side wall on the bottom plate 12a. The container 11 is made of a light-transmitting material such as glass, so that incident light can be applied to the electrodes 13 and 14 (diffraction grating) through the bottom plate 12a.

  The electrodes 13 and 14 are formed on the bottom plate 12a using a mask patterning technique. In this embodiment, the electrodes 13 and 14 are formed on the bottom plate 12a. However, when the container 11 is sufficiently deep, the electrodes 13 and 14 are formed on the frame 12b serving as the side wall instead of the bottom plate 12a. May be.

  In the electrode 13, linear electrode piece unevenly distributed regions 13f adjacent to two parallel linear electrode pieces 13a and 13b and linear electrode piece absent regions 13c in which no linear electrode pieces are formed are alternately repeated. All of the linear electrode pieces 13a and 13b are electrically connected by the connecting portion 13d, and have a so-called comb electrode structure.

  The same applies to the electrode 14, and a linear electrode piece unevenly distributed region 14f in which two parallel linear electrode pieces 14a and 14b are adjacent to each other and a linear electrode piece absent region 14c in which no linear electrode pieces are formed are provided. The linear electrode pieces 14a and 14b are electrically connected to each other through the connecting portion 14d to form a comb electrode structure.

Then, the linear electrode pieces 14 a and 14 b of the electrode 14 are arranged at the position of the linear electrode piece absent region 13 c of the electrode 13, and the straight electrode pieces 13 a and 13 b of the electrode 13 and the straight line of the electrode 14 are arranged. The linear electrode pieces 13a, 13b, 14a, and 14b form a diffraction grating so that the electrode pieces 14a and 14b are continuously arranged at regular intervals.
The size of the diffraction grating is preferably about 0.5 μm to 20 μm for both the electrode width d1 and the electrode interval d2 constituting the diffraction grating. However, the shape of the diffraction grating is not limited as long as it can generate diffracted light. The dimensions are not particularly limited. For example, the electrode width d1 and the electrode interval d2 may have different dimensions, or the diffraction grating shape may not be formed of a linear electrode piece. In the diffraction grating of this embodiment, a linear electrode piece having an electrode width of 10 μm and an electrode interval of 10 μm is used. In this case, the grating interval d of the diffraction grating is d1 + d2.

  The AC power supply 15 is an AC power supply having a voltage and frequency that can cause dielectrophoresis. Specifically, an AC power supply capable of applying an AC voltage of about 1 to 100 V, 10 KHz to 10 MHz is used. In general, it is preferable to use a high-frequency power source.

  The type of the light source 16 may be selected according to the liquid sample to be measured. For example, it is preferable to use a He—Ne laser light source (wavelength 633 nm) or another laser light source.

  The lens optical system 17 is configured to converge the light source light and irradiate the electrodes 13 and 14 (diffraction grating). In addition, it is preferable that the incident angle of the light source light can be adjusted so that either transmitted diffracted light or reflected diffracted light can be obtained according to the measurement object and the measurement purpose.

When measuring transmitted diffracted light, the incident angle may be a condition that does not cause total reflection at the interface between the bottom of the container and the liquid sample. For example, the incident angle may be incident at an incident angle of 0 degree.
The photodetector 18 is arranged on the upper side of the liquid sample in order to detect the transmitted diffracted light. The light detector 18 is provided with an angle adjusting mechanism for measuring the diffraction angle so that the diffraction angle can be detected together with the intensity of the diffracted light. A photodiode or CCD is used for the photodetector 18. Instead of providing the angle adjustment mechanism, the diffraction angle may be measured using an array sensor in which a plurality of elements are arranged.

  Next, the measurement operation of the above apparatus will be described. First, incident light is irradiated from the light source 16 to the electrodes 13 and 14 without applying a voltage. The liquid sample is almost uniform throughout. At this time, the incident light is affected by a diffraction grating formed by the linear electrode pieces 13a, 13b, 14a, and 14b (hereinafter referred to as a diffraction grating (period d) by a periodic electrode), and is shown by a solid line in FIG. In addition, a diffracted light pattern (referred to as a basic diffracted light pattern) by transmitted diffracted light of −1st order, 0th order, 1st order,.

  Next, an AC voltage is applied between the electrode 13 and the electrode 14 by the AC power source 15. When particles (such as proteins) are present in the liquid sample, a dielectrophoretic action due to an alternating voltage works, and the particles move to a region where electric lines of force concentrate. 3 and 4 are diagrams for explaining the state of particles when an AC voltage is applied. As shown in the figure, the lines of electric force concentrate due to the adjacent positive and negative electrodes, or between the linear electrode piece 14b and the linear electrode piece 13a, or between the linear electrode piece 13b and the linear electrode piece 14a. In between, the particles are aggregated, and the particle concentration region P having a high refractive index is formed. The particle concentration region P having a high refractive index is generated with a period (2d) twice as long as the grating interval d, and forms a diffraction grating with a period 2d by the refractive index distribution at this time.

  The incident light is influenced by the diffraction grating (period d) by the periodic electrode to generate a basic diffracted light pattern, and is also influenced by the diffraction grating (period 2d) by the refractive index distribution, and is indicated by a broken line in FIG. As described above, a diffracted light pattern by -1st order, 1st order,... Transmitted diffracted light is generated at an angular position satisfying the diffraction condition of the period 2d. (However, the 0th-order transmitted diffracted light overlaps the 0th-order diffracted light in the basic diffracted light pattern).

  Therefore, in addition to the basic diffracted light pattern, the presence or absence of particles moving by dielectrophoresis can be measured based on whether or not the diffracted light by the diffraction grating having the refractive index distribution with the period 2d is observed. Since the measurement of newly generated diffracted light is not affected by the basic diffracted light pattern, it is possible to detect a change in refractive index due to voltage application with high sensitivity.

  In addition, the intensity of new diffracted light generated by the refractive index distribution is determined by the difference between the maximum and minimum values of the periodic refractive index distribution, so even if the temperature of the liquid sample changes, the refractive index of the entire solution changes equally. If you do, you will not be affected.

In the above embodiment, the electrodes 13 and 14 each have two linear electrode pieces adjacent to each other, but three linear electrode pieces may be adjacent to each other at equal intervals. In this case, the number of new diffracted light that increases due to the diffraction of the refractive index distribution shown in FIG. 5 doubles. Similarly, four or more linear electrode pieces may be adjacent to each other, but if the number is increased too much, the number of new diffracted light will increase too much, so about 2 to 5 are preferable. .
(Embodiment 2)
In Embodiment 1, transmitted diffracted light is used, but reflected diffracted light may be used. If reflected diffracted light is used, it is possible to easily detect diffracted light even for a liquid sample having light absorption. Further, by using surface plasmon resonance, detection with higher sensitivity becomes possible.

  In the case of an optical measuring apparatus that measures reflected diffracted light, the position of the photodetector 18 is arranged on the lower side of the bottom plate 12a in the apparatus configuration shown in FIG.

  In the case of reflected diffracted light measurement, it is preferable that the incident angle of incident light emitted from the light source 16 is set so that total reflection occurs, and the amount of reflected diffracted light is increased as much as possible. For example, when the container 11 is made of glass and a water-based sample is held as a liquid sample, the incident angle is preferably set to about 46 degrees.

  The measurement operation is substantially the same as the operation described in the first embodiment except that the detection angle range by the photodetector 18 is different from that in the first embodiment, and will be described with reference to FIG. (However, the position of the photodetector 18 is on the lower side of the bottom plate 12a).

  First, similarly to the case of FIG. 1 in which transmission diffracted light measurement is performed, incident light is irradiated from the light source 16 without applying a voltage to the electrodes 13 and 14. At this time, under the influence of the diffraction grating (period d) by the periodic electrodes of the linear electrode pieces 13a, 13b, 14a, and 14b, as shown by the solid line in FIG. A reflected diffracted light pattern (referred to as a basic diffracted light pattern) is generated by reflected light of primary, 0th, 1st,...

  Next, an AC voltage is applied between the electrode 13 and the electrode 14 by the AC power source 15. When particles (for example, proteins) are present in the liquid sample, a dielectrophoretic action due to an AC voltage works, and the particles move to a position where electric lines of force concentrate. FIG. 6 is a diagram for explaining the state of particles when an AC voltage is applied. As in the case of the first embodiment, the positive electrode and the negative electrode are adjacent to each other, which is a region where the lines of electric force concentrate, or between the linear electrode piece 14b and the linear electrode piece 13a, or the linear electrode piece 13b. And a linear electrode piece 14a, a particle concentration region P having a high refractive index is formed. The particle concentration region P is generated with a period (2d) twice as long as the grating interval d, and forms a diffraction grating with a period 2d by a refractive index distribution.

  The incident light is affected by the diffraction grating (period d) by the periodic electrode to generate a basic diffracted light pattern, and is also influenced by the diffraction grating (period 2d) by the refractive index distribution, and is indicated by a broken line in FIG. As described above, a diffracted light pattern is generated by reflected diffracted light of −1st order, 1st order,... (However, the 0th-order transmitted diffracted light overlaps the 0th-order diffracted light in the basic diffracted light pattern).

  Therefore, also in this case, the presence / absence of particles that can move by dielectrophoresis can be measured depending on whether or not the diffracted light by the diffraction grating having the refractive index distribution of the period 2d is observed. Since the measurement of newly generated diffracted light is not affected by the basic diffracted light pattern, it is possible to detect a change in refractive index due to voltage application with high sensitivity.

  In addition, the intensity of new diffracted light generated by the refractive index distribution is determined by the difference between the maximum and minimum values of the periodic refractive index distribution, so even if the temperature of the liquid sample changes, the refractive index of the entire solution changes equally. If you do, you will not be affected.

  In the above-described reflected diffracted light measurement, surface plasmon resonance can be generated by using materials such as Au and Ag having excellent light reflection characteristics for the electrodes 13 and 14, so that high sensitivity is obtained using the surface plasmon resonance. Measurements can be made.

That is, the incident angle from which the surface plasmon resonance occurs can be set by irradiating the incident light from the light source 16 while changing the incident angle. When the incident angle is set in this way, the phase at the time of reflection at the electrodes 13 and 14 changes sensitively according to the refractive index of the solution immediately above the electrodes. With the change in refractive index, the intensity of diffracted light changes greatly. Therefore, highly sensitive measurement is possible by detecting the diffracted light intensity as well as the diffracted light angle through such surface plasmon resonance.
(Embodiment 3)
In the first and second embodiments, the portion where the positive electrode and the negative electrode are adjacent (the lines of electric force are concentrated) is repeated at a period that is an integral multiple of twice or more the grating period of the diffraction grating. Therefore, as shown in FIG. 2, an electrode shape in which two (or more) adjacent linear electrode pieces and a linear electrode piece absent region are periodically repeated is used.

  The electrode shape for repeating the electric field line concentration portion with a period that is an integer multiple of twice or more the grating period of the diffraction grating is not limited to the above, and various shapes are conceivable.

  FIG. 8 is a diagram showing a configuration of a modified embodiment for repeating the electric field line concentration portion with a period that is an integral multiple of twice or more the grating period of the diffraction grating.

  This electrode includes a pair of electrodes 21 and 22 and a linear floating portion 23 that is electrically independent from the electrodes 21 and 22. The floating portion 23 is formed simultaneously with the electrodes 21 and 22 by using a mask pattern technique. The electrode 21 and the electrode 22 are arranged so that the linear electrode pieces 21a and 22a are periodically arranged at regular intervals, and the ends of the linear electrode pieces are connected to each other by connection parts 21b and 22b. It has a comb electrode structure. The linear electrode pieces 21a of the electrodes 21, the linear electrode pieces 22a of the electrodes 22, and the floating portions 23 are alternately arranged to form a diffraction grating.

When an alternating voltage is applied between the electrode 21 and the electrode 22 to generate dielectrophoresis in the electrode having this configuration, for example, as shown in FIG. 9, a refractive index distribution having a period three times the period of the diffraction grating. Can be generated.
(Embodiment 4)
In the first to third embodiments, an AC power source is used to concentrate the particles by causing dielectrophoresis at the location where the lines of electric force concentrate, and the change in the refractive index due to the concentration of the particles is used. The diffracted light is changed. However, the change in the refractive index at the location where the lines of electric force are concentrated can be generated by methods other than dielectrophoresis.

  For example, when ionic particles are contained in a liquid sample, by applying a voltage having a direct current component to the electrode pair, the ion particles are moved to a portion where the lines of electric force are concentrated by electrophoresis. The refractive index distribution may be generated. Further, a refractive index distribution may be formed by generating a refractive index change in a concentrated region of electric lines of force by an electrochemical reaction.

  The present invention can be used for an optical measuring device for optically measuring particles in a liquid sample.

1 is a schematic cross-sectional view showing a configuration of an optical measurement apparatus that is an embodiment of the present invention. FIG. 2 is a top view of the optical measuring device of FIG. 1. The figure explaining the refractive index distribution state when an alternating voltage is applied (cross-sectional view). The figure (top view) explaining a refractive index state when an alternating voltage is applied. The figure explaining the diffracted light pattern by the optical measuring device of FIG. In the optical measuring device which is other one Embodiment of this invention, the figure (sectional drawing) explaining a refractive index distribution state when an alternating voltage is applied. The figure explaining the diffracted light pattern by the optical measuring device of FIG. The figure which shows the electrode pattern shape of the optical measuring device which is other embodiment of this invention. The figure explaining the refractive index distribution state when the alternating voltage of the optical measuring device of FIG. 8 is applied.

Explanation of symbols

11: Container 12a: Bottom plate 12b: Frame bodies 13, 14 Electrodes 13a, 13b, 14a, 14: Linear electrode piece 15: AC power supply 16: Light source 18: Photo detectors 21, 22: Electrodes 22a, 22b: Linear electrodes Piece 23: Floating part

Claims (7)

A light source, a power source, a container for holding a liquid sample, a diffraction grating formed at a position in contact with the liquid sample in the container and generating a basic diffraction light pattern when irradiated with light from the light source, and at least one of the diffraction gratings Comprising a pair of electrodes capable of applying positive and negative voltages from a power source, and a photodetector for detecting diffracted light by the diffraction grating,
By applying a voltage to the electrode pair to change the refractive index distribution of the liquid sample, a modified diffracted light pattern different from the basic diffracted light pattern is generated, and information about the liquid sample is measured based on the deformed diffracted light pattern An optical measuring device. 2. The optical measurement according to claim 1, wherein an AC power source is used as the power source, and an AC voltage is applied to the electrode pair to cause dielectrophoresis in the liquid sample to generate a deformed diffracted light pattern. apparatus. The electrode pair is arranged so that a portion where the positive electrode and the negative electrode are adjacent to each other is repeated at a period that is an integral multiple of twice or more the grating period of the diffraction grating. Optical measuring device. Each electrode constituting the electrode pair is composed of a plurality of linear electrode pieces arranged in parallel and a connecting portion for electrically connecting the linear electrode pieces,
Furthermore, each electrode is formed such that at least two linear electrode pieces are adjacent to each other, and linear electrode piece unevenly distributed regions and linear electrode piece absent regions where no linear electrode pieces are present are alternately arranged,
4. The optical measurement apparatus according to claim 3, wherein a diffraction grating is formed so that the linear electrode piece unevenly distributed region of the other electrode overlaps the linear electrode piece absent region of one electrode. . Each electrode constituting the electrode pair is composed of a plurality of linear electrode pieces arranged in parallel and a connecting portion for electrically connecting the linear electrode pieces, and the diffraction grating is a linear electrode of each electrode. It is formed by regularly arranging a piece and a floating portion made of a linear member having substantially the same shape as that of the linear electrode piece and not electrically connected to any electrode. The optical measuring device according to claim 3. At least a part of the container is formed of a material that transmits the light source light, and an electrode pair is formed on the container part that transmits the light source light. 2. The optical measuring device according to claim 1, wherein diffracted light transmitted through the liquid sample or diffracted light reflected by the liquid sample is detected. The optical measurement apparatus according to claim 1, wherein the electrode pair is formed of a metal film that causes surface plasmon resonance when irradiated with light from a light source.

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