JP2020038226A - Optical measurement device - Google Patents

Abstract

To provide an optical characteristics measurement system which can be set up in a relatively short time and enables the detection sensitivity thereof to be more improved.SOLUTION: A first measurement device 100 includes: a first detection element 108 arranged in a housing 102; first cooling means 110, 111, 112, 114 at least partially joined to the first detection element and cooling the detection element; and suppression means 130, 132, 136, 120 suppressing change in temperature occurring around the detection element in the housing.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an optical property measurement system capable of measuring optical properties, and a calibration method for the optical property measurement system.

  In order to evaluate characteristic values of materials or reagents containing a photosensitizer, there is a need to measure weak light emitted from those substances. For example, Japanese Patent Application Laid-Open No. 09-159604 (Patent Document 1) discloses a sample containing a photosensitizer having a light absorption property at an arbitrary wavelength from an ultraviolet region to a visible region, and a method for directly and indirectly detecting light. A singlet oximeter that is unstable and can measure even a sample that is available in a small amount is disclosed.

  In addition, JP-A-09-292281 (Patent Document 2), WO 2010/084566 (Patent Document 3), and JP-A-2011-196735 (Patent Document 4) contain a substance that emits fluorescent light. A measuring device and a measuring method for measuring a quantum efficiency indicating a ratio of a photon quantity absorbed by a sample to a photon quantity of fluorescence generated from the sample are disclosed.

JP 09-159604 A JP-A-09-292281 International Publication No. 2010/084566 JP 2011-196735 A

  The singlet oxygen measurement device disclosed in Patent Literature 1 uses a liquid nitrogen-cooled germanium detector to increase detection sensitivity. By cooling the detection element using liquid nitrogen or the like, the detection element is stabilized and the detection dynamic range can be expanded. On the other hand, cooling the detection element with liquid nitrogen requires several hours of preparation, including pre-cooling, until it can be actually used, which is not practical.

  There is a demand for an optical property measurement system that can be set up in a relatively short time and that can further increase the detection sensitivity.

  According to an aspect of the present invention, there is provided an optical property measuring system including a first measuring device. The first measuring device includes a first detection element disposed in a housing, a first cooling unit that is at least partially joined to the first detection element and cools the detection element, and a detection element in the housing. And suppression means for suppressing a temperature change occurring around the device.

  Preferably, the suppression means includes a second cooling means which is at least partially joined to the housing and discharges heat in the housing to the outside of the housing.

  Preferably, the suppression means is provided around the housing and includes heat insulation means for suppressing heat from entering the housing from around the housing.

Preferably, the optical property measuring system further includes a second measuring device. The first measurement device further includes a first diffraction grating arranged in association with the first detection element and configured to guide light in a first wavelength range to the first detection element. The second measurement device is configured to be disposed in the housing and to be associated with the second detection element, and to guide light in a second wavelength range to the second detection element. A second diffraction grating. The first detecting element of the first measuring device is configured to have higher detection sensitivity than the second detecting element of the second measuring device.

  Preferably, the optical property measurement system further includes a branch fiber that branches light from the measurement target and guides the light to the first and second measurement devices, respectively.

  Preferably, the first measurement device is configured to have a detection sensitivity for a wavelength component in a near infrared region. The second measuring device is configured to have detection sensitivity for at least a part of wavelength components included in a range from an ultraviolet region to a visible region.

  According to another aspect of the present invention, there is provided a method for calibrating an optical property measurement system including a first measurement device and a second measurement device configured to have lower detection sensitivity than the first measurement device. Provided. According to the calibration method of the optical characteristic measurement system, a light source whose energy value is previously valued and a second measurement device are arranged according to the first installation condition, and light from the light source is received by the second measurement device. Determining the energy calibration coefficient of the second measurement device based on the obtained output value; and arranging the light source and the second measurement device according to the second installation condition, and transmitting the light from the light source to the second measurement device. Determining a converted value of the energy of the light source corresponding to the second installation condition based on an output value obtained by receiving light by the measurement device and an energy calibration coefficient of the second measurement device; According to the conditions, the light source and the first measuring device are arranged, the output value obtained by receiving the light from the light source by the first measuring device, and the converted value of the energy of the light source corresponding to the second installation condition. Based on the energy of the first measuring device And determining the over calibration factor.

  According to an embodiment of the present invention, it is possible to realize an optical characteristic measurement system that can be set up in a relatively short time and can further increase the detection sensitivity.

  Further, according to an embodiment of the present invention, there is provided an optical characteristic measurement system including a first measurement device and a second measurement device configured to have lower detection sensitivity than the first measurement device. A calibration method is provided.

1 is a schematic diagram illustrating a configuration example of an optical characteristic measurement system including an optical characteristic measurement device according to an embodiment. FIG. 2 is a diagram for explaining a method for measuring optical characteristics using the optical characteristic measurement system shown in FIG. 1. FIG. 2 is a schematic diagram illustrating a device configuration of a data processing device included in the optical characteristic measurement system illustrated in FIG. 1. FIG. 2 is a schematic diagram illustrating a device configuration of a measurement device included in the optical property measurement system illustrated in FIG. 1. 5 is a graph showing a result of evaluating an influence of a temperature drift of the measurement device shown in FIG. It is a schematic diagram which shows the principal part of the apparatus structure of the optical characteristic measuring system suitable for the measurement of quantum efficiency. 5 is a flowchart showing a procedure of a measuring method using the measuring device according to the present embodiment. FIG. 7 is a diagram illustrating a measurement example when singlet oxygen is generated from fullerene (C ₆₀ ) in a solvent using the optical property measurement system illustrated in FIG. 6. 5 is a flowchart showing a procedure for calibrating the optical property measurement system according to the present embodiment. FIG. 9 is a schematic diagram for describing a procedure for performing calibration on the optical property measurement system according to the present embodiment.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions have the same reference characters allotted, and description thereof will not be repeated.

<A. System configuration example>
First, an optical characteristic measuring system 1 including an optical characteristic measuring device (hereinafter, also abbreviated as “measuring device”) according to the present embodiment will be described. FIG. 1 is a schematic diagram showing a configuration example of an optical property measuring system 1 including an optical property measuring apparatus according to the present embodiment.

  With reference to FIG. 1, an optical characteristic measuring system 1 includes a light source 4, an integrator 6, a system main body 2 that houses a measuring device 100, and a data processing device 200. FIG. 1 illustrates a configuration example in which the light source 4, the integrator 6, and the measurement device 100 are housed in one housing. However, the configuration is not limited to this, and some or all of the components may be configured separately. Good. In this case, the optical characteristic measuring system may be constituted by only one or a plurality of measuring devices 100.

  The optical property measuring system 1 shown in FIG. 1 can measure various optical properties. The optical characteristics include, for example, total luminous flux, illuminance (or spectral irradiance), luminance (or spectral radiance), luminous intensity, color rendering (chromaticity coordinates, excitation purity, correlated color temperature, color rendering), absorption Includes rate, transmittance, reflectance, emission spectrum (and peak wavelength, half-wave value), excitation spectrum, external quantum efficiency (or external quantum yield), internal quantum efficiency (or internal quantum yield), etc. .

  In the following description, a sample containing a substance that emits fluorescence is mainly irradiated with excitation light of a predetermined wavelength (typically, light in the ultraviolet to visible range), and fluorescence (typically, light) generated from the sample is emitted. FIG. 2 illustrates an example in which near-infrared to infrared light is detected. In this case, the optical characteristics of the measurement object typically include the spectrum and the quantum efficiency of the fluorescence generated from the sample.

  The light source 4 generates excitation light for irradiating the sample. As the light source 4, for example, a xenon discharge lamp (Xe lamp), a laser diode, a white LED (Light Emitting Diode), or the like is used. When measuring the quantum efficiency of the sample, it is preferable to use monochromatic light having a single wavelength according to the characteristics of the sample as the excitation light. When the generated excitation light has a wide wavelength band (when a white light source such as a xenon discharge lamp is used), a wavelength band transmission filter for selecting a target monochromatic light may be provided.

  The optical characteristic measuring system 1 employs a hemispherical integrating sphere as the integrator 6. As the integrator 6, a spherical type may be used. By using a hemispherical integrating sphere, the measurement accuracy can be improved, and the sample can be more easily attached and detached.

  FIG. 2 is a diagram for explaining a method for measuring optical characteristics using the optical characteristic measurement system 1 shown in FIG. FIG. 2A shows an example of a measurement method for measuring a powder sample or a solid sample, and FIG. 2B shows an example of a measurement method for measuring a solution sample.

Referring to FIG. 2A, integrator 6 forms a hemispherical integration space therein. More specifically, the integrator 6 includes a hemispherical portion 61 and a disc-shaped light diffusion / reflection layer disposed so as to pass through the substantial center of curvature of the hemispherical portion 61 and close the opening of the hemispherical portion 61. Planar mirror 6 including 62a
Consists of two. The light diffusion / reflection layer 61a is provided on the inner surface (inner wall) of the hemisphere 61. The light diffusion reflection layer 61a is typically formed by applying or spraying a light diffusion material such as barium sulfate or PTFE (polytetrafluoroethylene). The plane mirror 62 has a light diffusion reflection layer 62 a that performs specular reflection (specular reflection and diffuse reflection) on the inner surface side of the hemispherical portion 61. By arranging the light diffusion / reflection layer 62a of the plane mirror 62 toward the inside of the hemisphere 61, a virtual image of the hemisphere 61 is generated. When a space (real image) defined inside the hemispherical portion 61 and a virtual image generated by the plane mirror 62 are combined, it is possible to obtain substantially the same illuminance distribution as in the case where a spherical integrator is used.

  The sample SMP1, which is a powder sample or a solid sample, is mounted on a sample window 65 formed in a region including the apex of the hemisphere 61. The sample SMP1 is mounted on the sample window 65 such that the substance that emits fluorescent light is exposed inside the hemisphere 61.

  The excitation light generated by the light source 4 propagates through the optical fiber 5 and irradiates the sample SMP1 disposed inside the integrator 6 through the light projecting optical system 50. The light projecting optical system 50 includes a condenser lens 52, and condenses the excitation light from the light source 4 to the sample SMP1. A light projecting window 64 for guiding the excitation light into the integrator 6 is formed in the plane mirror 62.

  Light (typically, fluorescence) generated by receiving the excitation light from the sample SMP1 is repeatedly reflected inside the integrator 6, so that the illuminance appearing on the inner surface of the integrator 6 is made uniform.

  An observation window 67 for observing the illuminance on the inner surface of the integrator 6 is formed in the plane mirror 62, and a light extraction unit 68 is provided in association with the observation window 67. The end of the optical fiber 7 that is optically connected to the measuring device 100 is connected to the light extraction unit 68. That is, light having an intensity corresponding to the illuminance on the inner surface of the integrator 6 (corresponding to the visual field range viewed from the observation window 67) enters the measuring device 100. The measurement device 100 measures optical characteristics of the sample SMP1 and the like from light observed through the optical fiber 7.

  As shown in FIG. 2A, the user only needs to mount the sample SMP1 on the sample window 65 provided at the vertex of the hemispherical portion 61 (the lowermost portion in the drawing), so that it is necessary to measure a plurality of samples SMP1. Even if there is, the work of mounting and exchanging the sample can be simplified.

  Referring to FIG. 2 (B), when measuring a sample SMP2 which is a solution sample, a sample holder 63 is attached to a sample window 66 formed at the center of the plane mirror 62, and the sample is placed in the sample holder 63. SMP2 is arranged. At this time, a standard reflection member 69 is attached to the sample window 65 formed in a region including the vertex of the hemispherical portion 61.

  The light projecting optical system 50 is arranged at a position where the sample holder 63 is extended in the length direction in association with the sample window 66. The light projecting optical system 50 irradiates the sample SMP2 with the excitation light from the light source 4 through the inside of the sample holder 63. Light (typically, fluorescence) generated by the sample SMP2 receiving the excitation light is repeatedly reflected inside the integrator 6, so that the illuminance appearing on the inner surface of the integrator 6 is made uniform. The measuring apparatus 100 measures the optical characteristics of the sample SMP2 and the like from the light observed through the optical fiber 7 in the same manner as in FIG.

  In the use state shown in FIG. 2B, the standard reflection member is also mounted on the light emitting window 64 (see FIG. 2A).

Depending on the material or characteristics of the sample, re-excitation fluorescence emission may occur. The re-excitation fluorescence emission is a phenomenon in which the excitation light reflected on the sample surface is diffusely reflected in the integrator 6 and re-enters the sample, thereby causing further emission. In the optical property measurement system 1, it is also possible to correct such an error due to the re-excitation fluorescence emission.

  Referring to FIG. 1 again, measuring device 100 receives light observed through optical fiber 7 and outputs a measurement result (a spectrum or the like). The data processing device 200 calculates the optical characteristics of the sample by processing the measurement result from the measuring device 100. Details of the measuring device 100 will be described later.

The data processing device 200 is typically realized by a general-purpose computer. FIG. 3 is a schematic diagram illustrating a device configuration of the data processing device 200 included in the optical characteristic measurement system 1 illustrated in FIG. The data processing device 200 includes a CPU (Central Processing Unit) 202 that executes various programs including an operating system (OS).
And a main memory 204 for temporarily storing data necessary for the CPU 202 to execute the program, and a hard disk 206 for nonvolatilely storing the program to be executed by the CPU 202. The components constituting the measuring apparatus 100 are communicably connected to each other via a bus 220.

Measurement program 208 for implementing the measurement method according to the present embodiment is stored in hard disk 206 in advance. Such a measurement program 208 is transmitted from a CD-ROM (Compact Disk-Read Only Memory) drive 210 to a CD as an example of a recording medium.
-Read from the ROM 212 or the like. That is, measurement program 208 for implementing the measurement method according to the present embodiment is stored in a recording medium such as CD-ROM 212 and distributed. Alternatively, the measurement program 208 may be distributed via a network. In such a case, the measurement program 208 is received via the network interface 214 of the data processing device 200 and stored in the hard disk 206.

  The display 216 displays measurement results and the like to the user. The input unit 218 typically includes a keyboard, a mouse, and the like, and receives a user operation.

  Note that some or all of the above functions may be realized by a dedicated hardware circuit. Further, the data processing device 200 may be incorporated as a part of the system main body 2.

<B. Discovering new issues>
It is assumed that the sample is irradiated with excitation light having a wavelength component in the ultraviolet or visible range, and the emission generated by the sample is measured. In such a measurement, the light generated by the sample is often extremely weak having a wavelength component in the near-infrared region to the infrared region. In addition, some samples have a short life and only a short measurement time can be secured.

  For this reason, it is preferable to use a measuring device whose detection sensitivity is increased as much as possible. As in the prior art, there is also known a method of increasing the detection sensitivity by cooling the detection element using liquid nitrogen or the like, but there are also problems that a long time is required for setup and handling is not easy. is there.

  Therefore, realizing a measurement device using a detection element that can be used at room temperature without special cooling such as liquid nitrogen will further enhance the convenience of measurement. Such a detection element used at normal temperature is provided with a function of keeping the temperature of the detection element itself constant in order to avoid disturbance due to temperature.

The present inventors increase the detection gain of the detection element in order to detect extremely weak light, and despite the fact that the temperature of the detection element itself is kept constant, the ambient temperature of the measurement device is reduced. I found a new issue of being affected. According to the earnest study of the inventors of the present application, as the ambient temperature of the measuring device changes, a temperature change also occurs inside the measuring device, and the detection element with an increased gain also changes the radiant heat due to the temperature change. As a result, it was concluded that although the intensity of the light to be measured did not change, an error was caused in the measurement result due to the influence. Therefore, the inventors of the present application have invented a measuring device 100 that employs a function that does not cause an effect of a temperature change occurring inside the measuring device, that is, an effect of radiant heat, in addition to the detecting element itself. According to measuring apparatus 100 according to the present embodiment, stable measurement is possible even when the ambient temperature of measuring apparatus 100 changes.

<C. Configuration example of measurement device 100>
Next, a configuration example of measurement apparatus 100 according to the present embodiment will be described.

  FIG. 4 is a schematic diagram illustrating a device configuration of the measuring device 100 included in the optical characteristic measuring system 1 illustrated in FIG. Referring to FIG. 4, measurement apparatus 100 is a spectral light receiver, and includes optical slit 104, concave diffraction grating 106, and detection element 108. These components are arranged inside the housing 102.

  A connection member 116 for attaching the end of the optical fiber 7 is provided in a part of the housing 102. The optical axis of the opening end of the optical fiber 7 is aligned with the central axis of the optical slit 104 by the connecting member 116. Light extracted from the integrator 6 (hereinafter also referred to as “measurement light”) propagates through the optical fiber 7 and passes through the optical slit 104 of the measuring device 100. The measurement light is incident on the concave diffraction grating 106 after the cross-sectional diameter is adjusted by the optical slit 104.

  When the measurement light enters the concave diffraction grating 106, each wavelength component included in the measurement light is optically separated. That is, when the measuring light is diffracted by the concave diffraction grating 106, each wavelength component included in the measuring light travels in a different direction according to the length of the wavelength. Each wavelength component is incident on a detection element 108 that is optically aligned with the concave diffraction grating 106. As described above, the concave diffraction grating 106 is arranged in association with the detection element 108, and is configured to guide light in a predetermined wavelength range (in the present configuration example, near infrared to infrared) to the detection element 108. I have.

As the detection element 108, an array sensor in which a plurality of mutually independent detection surfaces are arranged is used. As the detection element 108, a CCD (Charge-Coupled Device) image sensor may be employed. The number and length of the detection surfaces constituting the detection element 108 are designed according to the diffraction characteristics of the concave diffraction grating 106 and the wavelength width to be detected. The detection element 108, which is an array sensor, detects the intensity spectrum of the measurement light for each predetermined wavelength width.

The detection element 108 has a self-cooling function of being at least partially joined to the detection element 108 and cooling the detection element 108. The detecting element 108 is a self-cooling type detecting element, which reduces thermal noise and dark current (dark current), thereby increasing detection sensitivity and improving the S / N (Signal to Noise) ratio. It is configured to be. Specifically, the detection element 108 has a base 110 having a cooling function. A function for cooling the detection element 108 is mounted inside the base 110. Typically, an electronic cooling element 111 such as a Peltier element may be employed inside the base 110.

  A cooling fin 112 is joined to the base 110 on a side opposite to the detection element 108 via a joining layer 113. A part of the heat generated by the detecting element 108 is absorbed by the electronic cooling element 111 inside the base 110, and another part is transferred from the cooling fin 112 to the measuring device 100 via the base 110 and the bonding layer 113. Is released to the outside.

The current value of the electronic cooling element 111 of the base 110 is controlled by the cooling controller 114. The cooling controller 114 controls a current value and the like based on a detection value from a temperature sensor or the like (not shown) so that the detection element 108 is maintained at a predetermined temperature.

  Measuring apparatus 100 according to the present embodiment has, in addition to the cooling function of the detection element itself, a function that does not affect detection element 108 due to a change in radiant heat. That is, the measuring apparatus 100 has a function and a configuration for suppressing a temperature change occurring around the detection element 108 in the housing 102. The configuration example illustrated in FIG. 4 illustrates an example in which a temperature control function for maintaining a constant temperature of the internal space of the housing 102 and a heat insulating function for reducing heat intrusion into the housing 102 are combined. .

  The temperature control function is realized by a cooling mechanism which is at least partially joined to the housing 102 and discharges heat inside the housing 102 to the outside of the housing 102. More specifically, the temperature control function includes an electronic cooling element 130 arranged on a side surface of the housing 102 and a heat dissipation plate 132 joined to the electronic cooling element 130. The electronic cooling element 130 includes a Peltier element and the like, and the current value and the like are controlled by the cooling controller 134.

  Inside the heat radiation plate 132, a flow path (not shown) through which a refrigerant (typically, water or Freon) flows is formed. The heat radiating plate 132 is connected to the refrigerant circulation pump 136 through the refrigerant paths 138 and 139. The refrigerant circulation pump 136 circulates the refrigerant in the order of the refrigerant path 138, the radiating plate 132, and the refrigerant path 139. By the operation of the refrigerant circulation pump 136, a part of the heat inside the housing 102 is released to the outside from the heat radiation plate 132, and the heat is exchanged with the refrigerant in the heat radiation plate 132, and the circulation path of the refrigerant circulation pump 136 is formed. It is released outside on top. That is, the heat radiation plate 132 and the refrigerant circulation pump 136 promote cooling of the inside of the housing 102 by the electronic cooling element 130.

  As the temperature control function, a configuration in which the refrigerant is circulated between the cooling plate and the heat radiating plate 132 by the refrigerant circulation pump 136 has been exemplified. May be adopted.

  The heat insulation function is realized by a structure that is arranged around the housing 102 and that suppresses heat from entering the housing 102 from around the housing 102. More specifically, a heat insulating material 120 is arranged on the outer periphery of the housing 102 as a heat insulating function. As the heat insulating material 120, any material can be used. For example, a fiber heat insulating material such as glass wool and rock wool may be used. Alternatively, a foam-based heat insulating material such as urethane foam and polystyrene foam may be used. By arranging such a heat insulating material 120 on the outer periphery of the housing 102, it is possible to reduce heat penetration from the periphery into the inside of the housing 102.

  As described above, measuring device 100 according to the present embodiment has a function and a configuration that suppresses a temperature change occurring around detection element 108 so as not to be affected by a change in radiant heat. The configuration is not limited to the configuration example shown in FIG. 4 as long as it suppresses a temperature change occurring around the detection element 108, and any configuration may be employed.

  For example, FIG. 4 illustrates a configuration example of a combination of a temperature control function mainly including the electronic cooling element 130 and a heat insulation function mainly including the heat insulating material 120. However, even if only one of the functions is adopted. Good.

  As another configuration example, a vacuum layer may be provided on the outer peripheral side or the inner peripheral side of the housing 102 instead of the heat insulating material 120, so that heat penetration from the ambient temperature may be reduced. Alternatively, a temperature-controlled refrigerant (typically, dry air, nitrogen, or the like) may be circulated around the housing 102 to keep the temperature inside the housing 102 constant.

Furthermore, two or more of the above-described functions may be appropriately combined.
Measuring apparatus 100 according to the present embodiment performs detection based on the above-described new findings of the present inventors by controlling the temperature inside casing 102 in which detecting element 108 is disposed, thereby stabilizing the temperature. The influence of radiant heat on the element 108 can be reduced, the detection sensitivity can be increased, and the S / N ratio can be improved.

  In addition to the function and configuration for suppressing a temperature change occurring around the detection element 108 in the housing 102, the masking process is performed on a portion of the detection surface of the detection element 108 that is not used for measurement, thereby stabilizing the dark output. It can also improve the performance.

<D. Improvement effect>
Next, the effect of improving the temperature drift in the measuring apparatus 100 shown in FIG. 4 will be described. FIG. 5 is a graph showing a result of evaluating the influence of the temperature drift of the measuring device 100 shown in FIG. In FIG. 5, the measuring device 100 shown in FIG. 4, the temperature control function (the electronic cooling element 130, the radiating plate 132, the cooling controller 134, the refrigerant circulation pump 136) and the heat insulating function (the heat insulating material 120) shown in FIG. This is a result of evaluating a change in an output value when an ambient temperature is changed by disposing each measuring device (comparative example) in a constant temperature bath with respect to the measurement device.

  “Ambient temperature” shown in FIG. 5 indicates a temperature change in the thermostat. Specifically, the temperature was changed stepwise by 5 ° C every 2 hours within a range of 10 ° C to 30 ° C.

  The measurement device of the comparative example is one in which the detection sensitivity of the detection element is set as a standard ((1) standard sensitivity in FIG. 5 (comparative example)) and one in which the detection sensitivity of the detection element is increased (FIG. 5). (2) High sensitivity (Comparative Example)). On the other hand, the measurement device 100 shown in FIG. 4 was measured in a state where the detection sensitivity of the detection element was set to be high ((3) high sensitivity (embodiment) in FIG. 5).

  In each case, the output value after dark correction in a state where the incidence of the measurement light is blocked is shown. Each output value is an integrated value obtained by repeating imaging four times with an exposure time of 20 seconds. The measurement result shown in FIG. 5 is an output value after dark correction, and a smaller value is more preferable.

  As shown in FIG. 5, even when the measurement device of the comparative example is used at the standard sensitivity, the influence of the change in the ambient temperature is small, but when the detection sensitivity is increased, the measurement device is affected by the change in the ambient temperature. Thus, it can be seen that the output value fluctuates even under the same measurement conditions.

  On the other hand, the measuring apparatus 100 according to the present embodiment takes measures to reduce heat intrusion from the surroundings into the inside of the housing 102, so that the detection sensitivity is set to be high. The effect of changes in ambient temperature is small. As a result, it can be seen that the influence of noise can be reduced more than when the measuring device of the comparative example is used at the standard sensitivity.

<E. Configuration suitable for measuring quantum efficiency>
Next, a configuration example suitable for measurement of quantum efficiency will be described. For example, when measuring the quantum efficiency of a sample containing a substance that emits fluorescent light, the sample is irradiated with excitation light having a wavelength component in the ultraviolet or visible range, and the irradiated excitation light is measured. It is necessary to measure fluorescence having a wavelength component in a near-infrared region or an infrared region generated by the sample. Generally, the generated fluorescence is extremely weak as compared with the excitation light. In addition, there is a sample in which the life of the sample is short and only a short measurement time can be secured.

In such a case, a configuration may be adopted in which a first measurement device that mainly measures excitation light and a second measurement device that mainly measures fluorescence are combined. Hereinafter, an example of an apparatus configuration suitable for measuring the quantum efficiency of a substance that emits fluorescence will be described.

  FIG. 6 is a schematic diagram showing a main part of a device configuration of an optical property measurement system 1A suitable for measurement of quantum efficiency. Referring to FIG. 6, optical characteristic measurement system 1A includes a measurement device 100A for mainly measuring excitation light and a measurement device 100 for mainly measuring fluorescence.

  The optical property measurement system 1A includes a branch fiber that branches light from a measurement target and guides the light to the measurement device 100 and the measurement device 100A, respectively. That is, the optical fiber 7 connected to the light extraction unit 68 of the integrator 6 is split at the branching unit 73 into an optical fiber 71 connected to the measuring device 100A and an optical fiber 72 connected to the measuring device 100. . That is, the light observed through the optical fiber 7 is split into two and enters the measuring device 100 and the measuring device 100A, respectively.

  The measuring device 100A mainly measures the excitation light, and is designed so that the detection range is from the ultraviolet region to the visible region. On the other hand, the measuring device 100 is mainly for measuring fluorescence, and is designed so that the detection range is in the near infrared region to the infrared region. That is, the measuring device 100A is mainly configured to have detection sensitivity to wavelength components in the near-infrared region or the infrared region, and the measuring device 100 has at least some wavelengths included in the range from the ultraviolet region to the visible region. The components are configured to have detection sensitivity.

  The device configuration of the measuring device 100 is the same as the device configuration shown in FIG. 4 described above. On the other hand, as for the device configuration of the measuring device 100A, the same device configuration as that shown in FIG. 4 described above may be employed. However, when the excitation light is measured, the intensity of the light to be detected is high. It is not always necessary to provide the temperature control function (electronic cooling element 130, heat radiation plate 132, cooling controller 134, refrigerant circulation pump 136) and heat insulation function shown in FIG. The optical characteristic measurement system 1A shown in FIG. 6 employs a measurement device 100A in which the temperature control function and the heat insulation function are omitted.

  In accordance with the difference in the detection range between the measurement device 100A and the measurement device 100, the concave diffraction grating 106 of the measurement device 100A detects light in a predetermined wavelength range (in the present configuration example, near infrared region to infrared region). The concave diffraction grating 106 of the measuring apparatus 100 is configured to guide light in a different wavelength range (in the present configuration example, from the ultraviolet range to the visible range) to the detection element 108. ing.

  The detection element 108 of the measurement device 100A is set to have higher detection sensitivity than the detection element 108 of the measurement device 100. In other words, the measuring device 100 is configured to have lower detection sensitivity than the measuring device 100A.

  According to the optical characteristic measurement system 1A shown in FIG. 6, two measurement devices can measure in parallel, so that spectra from the ultraviolet region to the near infrared region (or infrared region) can be measured simultaneously. For example, as a function for measuring a spectrum from the ultraviolet region to the near-infrared region (or infrared region) with one measuring device, the wavelength of the detection target is sequentially changed by sequentially rotating the diffraction grating mechanically. One is known (ie, sweeping the wavelength). However, when such a function is adopted, there is a problem that it takes a relatively long time to complete the measurement of the target spectrum. In addition, when the measurement in the ultraviolet region and the visible region is completed, and a transition is made to the measurement in the near-infrared region or the infrared region, a mechanical switching operation is required, which may cause an unstable measurement.

On the other hand, the optical characteristic measuring system 1A shown in FIG. 6 includes an array sensor (the detection element 108 of the measuring device 100A) that can measure wavelengths from the ultraviolet region to the visible region at once, and a wavelength from the near infrared region to the infrared region. It has an array sensor (detection element 108 of measurement device 100) that can measure at once. By employing such a configuration, spectra in a wide wavelength range can be measured simultaneously and in a short time without sweeping the wavelength. In addition, by optimizing the detection sensitivity of the detection element 108 between the measurement device 100A for measuring excitation light having high emission intensity and the measurement device 100 for measuring fluorescence having low emission intensity, A rational and economical optical characteristic measuring system 1A capable of measuring quantum efficiency with high accuracy can be realized.

<F. Measurement method>
Next, a measuring method using the measuring apparatus 100 shown in FIG. 4 will be described. Note that the measurement can be performed in the same procedure when using the measuring device 100 and the measuring device 100A as in the optical property measuring system 1A shown in FIG.

  FIG. 7 is a flowchart showing a procedure of a measuring method using measuring apparatus 100 according to the present embodiment. Referring to FIG. 7, first, the user turns on the power of each component of the optical property measurement system and performs aging (step S100). Specifically, the aging includes stabilization of the self-cooling function of the detection element 108 constituting the measuring device 100, stabilization of the temperature in the housing 102 of the measuring device 100, stabilization of the light source 4, and the like.

  First, the user places the reference in the integrator 6 such that the excitation light from the light source 4 is directly applied to the reference (step S102). In the case of a powder sample or a solid sample, the standard reflection member 69 serves as a reference. In the case of a solution sample, a reference in which only a solvent is sealed in a container of the same type as the container in which the sample is sealed is used. The measurement device 100 measures the light when the reference is irradiated with the excitation light (step S104). This measured value is a value that indicates the influence of light absorption or the like that occurs when the sample is measured, and is used as a correction value.

  Subsequently, the user places the sample in the integrator 6 so that the sample is directly irradiated with the excitation light from the light source 4 (step S106). The measuring device 100 measures the light generated from the sample in response to the excitation light (Step S108). At this time, the measuring apparatus 100 measures the excitation light transmitted through the sample and / or the excitation light reflected by the sample, in addition to the light generated from the sample.

  Subsequently, the user makes settings for correcting the re-excitation fluorescence emission (step S110). The measuring device 100 measures the light generated from the sample in response to the excitation light (Step S112). As a setting for correcting the re-excitation fluorescence emission, in the case of a powder sample or a solid sample, the sample is disposed at a position where the excitation light from the light source 4 is not directly irradiated, and the excitation light reflected in the integrator 6 is set. The light generated when irradiates the sample is measured. In the case of a solution sample, the measurement is performed in a state where the standard reflection member 69 attached to the sample window 65 of the integrator 6 is removed so that the excitation light transmitted through the sample is not reflected into the integrator 6. .

  Finally, the data processing device 200 uses the result measured by the measuring device 100 in step S104, the result measured by the measuring device 100 in step S108, and the result measured by the measuring device 100 in step S112 to obtain a sample. Is calculated (for example, quantum efficiency or the like) (step S114).

<G. Measurement example>
Next, an example of a result of measuring a sample using the optical property measurement system 1A shown in FIG. 6 will be described. FIG. 8 is a diagram showing a measurement example when singlet oxygen is generated from fullerene (C ₆₀ ) in a solvent using the optical property measurement system 1A shown in FIG. FIG. 8A shows, as a comparative example, an example in which a measuring device using the detection sensitivity of the detection element as a standard is used, and FIG. 8B employs the configuration shown in FIG. An example using a measuring device set to increase the detection sensitivity of a detection element will be described.

More specifically, fullerene present in a solvent of deuterated benzene (C ₆ D ₆ ) was irradiated with excitation light to generate singlet oxygen. FIG. 8 shows an example of a result of measuring a spectrum of fluorescence generated in a process of generating singlet oxygen. As the light source 4 for generating the excitation light, a 532 nm laser light source (output 20 mW) was used.

  As shown in FIG. 8A, when the detection sensitivity of the detection element is set to the standard, the spectrum of the generated fluorescence cannot be measured. However, as shown in FIG. It can be seen that the spectrum of the generated fluorescence was measured when the height was increased.

  Further, the internal quantum efficiency of fullerene in the solvent was measured using the optical property measurement system 1A shown in FIG. It should be noted that the re-excitation fluorescence emission is also corrected. In order to examine the stability of the measurement, the same measurement was repeated for the same sample over three days (measurement was performed once a day, for a total of three times). The results are shown below.

-Day 1: 0.061%
-Day 2: 0.062%
-Day 3: 0.062%
According to the measurement results of the quantum efficiency, it can be seen that even a sample having a very small quantum efficiency can be measured stably.

<H. Calibration method>
The optical characteristic measuring system 1A shown in FIG. 6 includes two measuring devices 100 and 100A having different detection sensitivities. Considering the measurement of quantum efficiency and the like, it is necessary to perform energy calibration using the same standard light source. That is, it is necessary to match the magnitude of the energy converted from the measured value between the two measuring devices. On the other hand, since the detection sensitivities are different, it is not easy to perform energy calibration for two measurement devices using the same standard light source. Therefore, an example of a calibration method for measurement devices 100 and 100A that calibrate optical characteristic measurement system 1A according to the present embodiment will be described.

  FIG. 9 is a flowchart showing a procedure for calibrating optical characteristic measuring system 1A according to the present embodiment. FIG. 10 is a schematic diagram for describing a procedure for performing calibration on optical characteristic measurement system 1A according to the present embodiment.

Referring to FIGS. 9 and 10, first, for a standard lamp 150 used for calibration, a value of illuminance or the like at a distance L1 using an upper-level standard light source (international standard traceable light source) calibrated in advance. The attachment is performed (step S200). The standard lamp 150 is, for example, a 50 W light source. By step S200, an energy value for standard lamp 150 is obtained. The energy value is typically defined using the spectral irradiance [μW · cm ⁻² · nm ⁻¹ ].

  Subsequently, the standard lamp 150, which is a light source whose energy value is previously determined, and the measuring device 100A are arranged according to predetermined installation conditions. As an example, as shown in FIG. 10A, the standard lamp 150 and the measuring device 100A (standard sensitivity) are arranged at a distance L1 with their optical axes aligned (step S202). In order to reduce the influence of the stray light component or the like generated from the standard lamp 150, light shielding plate units 152 and 154 are arranged between the standard lamp 150 and the measuring device 100A.

  Then, the energy calibration coefficient of the measuring device 100A is determined based on the output value obtained by receiving the light from the standard lamp 150 by the measuring device 100A. That is, based on the output value from the measuring device 100A under the installation conditions shown in FIG. 10A, the energy calibration coefficient for the measuring device 100A is calculated (step S204).

  The energy calibration coefficient is a coefficient for converting an output value (signal value) from the measuring device into energy, and has a relation of energy = output value after dark correction (measured value−measured value at dark correction) / energy calibration coefficient. is there.

  In step S204, a value obtained by subtracting the dark correction value of the measurement device 100A (the measurement value Id2 output in the dark state) from the measurement value I2 of the measurement device 100A is determined by the energy value assigned to the standard lamp 150. It is calculated by dividing. That is, the energy calibration coefficient k2 of the measuring device 100A is equal to (I2−Id2) / (the energy value E1 assigned to the standard lamp 150).

  Subsequently, the standard lamp 150 as a light source and the measuring device 100A are arranged according to different installation conditions. As an example, as shown in FIG. 10B, the distance between the standard lamp 150 and the measuring device 100A (standard sensitivity) is reduced from the distance L1 to the distance L2, and then the distance between the standard lamp 150 and the measuring device 100A is reduced. The light reduction mesh 156 is arranged on the optical axis (step S206). As the light-attenuating mesh 156, for example, one having a transmittance of 1% (that is, light-attenuation to 1/100) can be adopted. The reason why the distance from the distance L1 to the distance L2 is reduced is to weaken the degree of dimming of the dimming mesh 156. If a more appropriate dimming mesh 156 can be prepared, the distance does not need to be changed.

  Then, based on the output value obtained by receiving the light from the standard lamp 150 by the measuring device 100A and the energy calibration coefficient of the measuring device 100A, the converted value of the energy of the standard lamp 150 corresponding to the current installation condition is calculated. decide. That is, based on the output values from the measuring device 100A under the installation conditions shown in FIG. 10B, a converted value of the energy of the standard lamp 150 that reflects the dimming mesh 156 and the distance L2 is calculated (step S208). . Specifically, a value obtained by subtracting the dark correction value (measured value Id2 output in the dark state) of the measuring device 100A from the measured value I2 ′ of the measuring device 100A is multiplied by the energy calibration coefficient k2 calculated in step S204. Thus, the converted energy value E2 is calculated. That is, converted energy value E2 = (I2'-Id2) * energy calibration coefficient k2.

  Subsequently, the standard lamp 150 as a light source and the measuring device 100 are arranged according to the different installation conditions. As an example, in the state shown in FIG. 10B, the measurement device 100 (high sensitivity) is used instead of the measurement device 100A (standard sensitivity) while maintaining the arrangement state of the light shielding plate units 152 and 154 and the light reduction mesh 156. Are arranged (see FIG. 10C) (step S210).

  Then, based on the output value obtained by receiving the light from the standard lamp 150 with the measuring device 100 and the converted value of the energy of the standard lamp 150 corresponding to the installation condition of FIG. Determine the energy calibration coefficient of That is, based on the output value from the measuring device 100 under the installation conditions shown in FIG. 10C, the energy calibration coefficient for the measuring device 100 is calculated (step S212). In step S212, a value obtained by subtracting the dark correction value (measured value Id1 output in the dark state) of the measuring device 100 from the measured value I1 of the measuring device 100 is divided by the converted energy value E2 calculated in step S208. It is calculated by: That is, the energy calibration coefficient k1 of the measuring device 100 = (I1-Id1) / (converted energy value E2 of the standard lamp 150).

  According to the above procedure, the energy calibration coefficient can be determined for each of the measuring device 100 and the measuring device 100A using the same standard light source.

  The wattage of the standard lamp 150, the difference between the distance L1 and the distance L2, the characteristics of the neutral density filter, and the like are determined according to the sensitivity difference between the measuring device 100 (high sensitivity) and the measuring device 100A (standard sensitivity). It may be adjusted appropriately.

<I. Advantages>
Measuring apparatus 100A according to the present embodiment has a function and a configuration for suppressing a temperature change occurring around detection element 108 in housing 102. By adopting such a function and configuration, even if the detection sensitivity of the detection element 108 is increased, it is possible to perform measurement with reduced influence of measurement noise. By using such a measuring apparatus 100A, for example, it is possible to irradiate a sample with excitation light having a wavelength component in the ultraviolet or visible range, and to stably measure extremely weak light emission generated from the sample. it can.

  Further, measuring apparatus 100A according to the present embodiment employs a method of cooling each of detection element 108 itself and the inside of housing 102 using an electronic cooling element, and thus a method of cooling using liquid nitrogen or the like. The measurement time including aging can be greatly reduced as compared to

  According to the optical characteristic measurement system 1A according to the present embodiment, it is possible to simultaneously measure light from the measurement target using the measurement devices 100 and 100A having different detection ranges. Each of the measuring device 100 and the measuring device 100A uses an array sensor (for example, a CCD image sensor) as a detecting element, and can acquire the intensities of a plurality of wavelength components at once. Thus, a spectrum over a wide band can be measured with high sensitivity. At the same time, the measurement time can be shortened as compared with the wavelength sweeping method.

  In addition, by optimizing the detection sensitivity for the measurement device 100 and the measurement device 100A, extremely weak light can be stably measured with good reproducibility without being affected by changes in the surrounding environment. Therefore, highly accurate measurement of quantum efficiency is possible. By adopting such a device configuration, for example, it is possible to detect, for example, fluorescence having a near-infrared wavelength component generated by a substance in a living body. It can also be applied to the development of various materials. Furthermore, it can be applied to the field of energy development, such as combining and using artificial light.

  From the above description, other advantages of the optical property measuring device and the optical property measuring system according to the present embodiment will be apparent.

  The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1,1A optical characteristic measuring system, 2 system body, 4 light sources, 5, 7, 71, 72
Optical fiber, 6 integrator, 50 light projecting optical system, 52 light condensing lens, 61 hemisphere, 61a light diffuse reflection layer, 62 plane mirror, 62a light diffuse reflection layer, 63 sample holder, 64 light projecting window, 65, 66 Sample window, 67 observation window, 68 light extraction part, 69 standard reflection member, 73 branch part, 100, 100A measuring device, 102 housing, 104 optical slit, 106 concave diffraction grating, 108 detection element, 110 base, 111, 130 Electronic cooling element, 112 cooling fin, 113 joining layer, 114, 134 cooling controller, 116
Connecting member, 120 heat insulating material, 132 heat radiation plate, 136 refrigerant circulation pump, 138, 139 refrigerant path, 150 standard lamp, 152, 154 light shielding plate unit, 156 light reduction mesh, 200 data processing device, 202 CPU, 204 main memory, 206 hard disk, 208 measurement program, 210 CD-ROM drive, 212 CD-ROM, 214 network interface, 216 display, 218 input section, 220 bus.

Claims (7)

An optical characteristic measurement system including a first measurement device,
The first measuring device comprises:
A first detection element disposed in the housing;
First cooling means that is at least partially joined to the first detection element and cools the detection element;
An optical characteristic measurement system comprising: a suppression unit configured to suppress a temperature change occurring around the detection element in the housing.   The optical property measurement system according to claim 1, wherein the suppression unit includes a second cooling unit that is at least partially joined to the housing and that discharges heat in the housing to the outside of the housing.   The optical characteristic measurement system according to claim 1, wherein the suppression unit includes a heat insulation unit disposed around the housing and configured to suppress heat intrusion from the periphery of the housing into the housing. The optical characteristic measurement system further includes a second measurement device,
The first measurement device further includes a first diffraction grating arranged in association with the first detection element and configured to guide light in a first wavelength range to the first detection element. ,
The second measuring device comprises:
A second detection element disposed in the housing;
A second diffraction grating arranged in association with the second detection element and configured to guide light in a second wavelength range to the second detection element,
4. The method according to claim 3, wherein the first detection element of the first measurement device is configured to have higher detection sensitivity as compared with the second detection element of the second measurement device. The optical property measurement system described in the above.   The optical characteristic measurement system according to claim 4, further comprising a branch fiber that branches light from the measurement target and guides the light to the first and second measurement devices. The first measuring device is configured to have a detection sensitivity to a wavelength component in a near infrared region,
The optical characteristic measurement system according to claim 4, wherein the second measurement device is configured to have a detection sensitivity for at least some wavelength components included in a range from an ultraviolet region to a visible region. A calibration method for an optical characteristic measurement system including a first measurement device and a second measurement device configured to have lower detection sensitivity than the first measurement device,
In accordance with a first installation condition, a light source whose energy value is previously valued and the second measuring device are arranged, and based on an output value obtained by receiving light from the light source by the second measuring device. Determining the energy calibration factor of the second measuring device;
According to a second installation condition, the light source and the second measuring device are arranged, and an output value obtained by receiving light from the light source by the second measuring device, and an output value of the second measuring device Determining a converted value of energy of the light source corresponding to the second installation condition based on the energy calibration coefficient;
According to the second installation condition, the light source and the first measurement device are arranged, and an output value obtained by receiving light from the light source by the first measurement device, and the second installation condition Determining an energy calibration coefficient of the first measurement device based on the converted value of the energy of the light source corresponding to the following.

Images