JP6833224B2 - Optical measuring device - Google Patents

Description

The present invention relates to an optical characteristic measurement system capable of measuring optical characteristics and a calibration method of the optical characteristic measurement system.

In order to evaluate the characteristic values of materials or reagents containing photosensitizers, there is a need to measure the faint light emitted by those substances. For example, Japanese Patent Application Laid-Open No. 09-159604 (Patent Document 1) directly and indirectly refers to a sample containing a photosensitizer having light absorption characteristics at any wavelength from the ultraviolet region to the visible region, and light directly and indirectly. We disclose a singlet oxygen measuring device that can measure even samples that are unstable and available in small quantities.

Further, Japanese Patent Application Laid-Open No. 09-292281 (Patent Document 2), International Publication No. 2010/084566 (Patent Document 3), and Japanese Patent Application Laid-Open No. 2011-196735 (Patent Document 4) contain a substance that emits fluorescence. A measuring device and a measuring method for measuring a quantum efficiency indicating a ratio between a photon amount absorbed by a sample and a photon amount of fluorescence generated from the sample are disclosed.

Japanese Unexamined Patent Publication No. 09-159604 Japanese Unexamined Patent Publication No. 09-292281 International Publication No. 2010/084566 Japanese Unexamined Patent Publication No. 2011-196735

The singlet oxygen measuring device disclosed in Patent Document 1 uses a liquid nitrogen-cooled germanium detector in order to increase the detection sensitivity. By cooling the detection element with liquid nitrogen or the like, the detection element can be stabilized and the detection dynamic range can be expanded. On the other hand, in order to cool the detection element with liquid nitrogen, it is not practical because it takes several hours to prepare for actual use, including pre-cooling.

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

According to certain aspects of the invention, an optical property measurement system comprising a first measuring device is provided. The first measuring device includes a first detection element arranged in the housing, a first cooling means that is at least partially bonded to the first detection element to cool the detection element, and a detection element in the housing. Includes means for suppressing temperature changes that occur around the environment.

Preferably, the suppressing means includes a second cooling means that is at least partially bonded to the housing and releases heat inside the housing to the outside of the housing.

Preferably, the suppressing means is arranged around the housing and includes heat insulating means for suppressing heat intrusion from the periphery of the housing into the housing.

Preferably, the optical property measuring system further includes a second measuring device. The first measuring device further includes a first diffraction grating which is arranged in association with the first detection element and is configured to guide light in the first wavelength range to the first detection element. The second measuring device is arranged in association with the second detecting element arranged in the housing and the second detecting element, and is configured to guide the light in the second wavelength range to the second detecting element. Includes a second diffraction grating. The first detection 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 measuring system further includes a branched fiber that branches the light from the object to be measured and directs it to the first and second measuring devices, respectively.

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

According to another aspect of the present invention, there is a method of calibrating an optical characteristic measuring system including a first measuring device and a second measuring device configured to have a lower detection sensitivity than the first measuring device. Provided. In the calibration method of the optical characteristic measurement system, a light source whose energy value is pre-valued and a second measuring device are arranged according to the first installation condition, and the light from the light source is received by the second measuring device. The step of determining the energy calibration coefficient of the second measuring device based on the obtained output value, the light source and the second measuring device are arranged according to the second installation condition, and the light from the light source is emitted from the second measuring device. A step of determining the converted value of the energy of the light source corresponding to the second installation condition based on the output value obtained by receiving light from the measuring device and the energy calibration coefficient of the second measuring device, and the second installation. The light source and the first measuring device are arranged according to the conditions, and 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. Includes a step of determining the energy calibration coefficient of the first measuring device based on.

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, an optical characteristic measuring system including a first measuring device and a second measuring device configured to have a lower detection sensitivity than the first measuring device. A calibration method is provided.

It is a schematic diagram which shows the structural example of the optical characteristic measurement system including the optical characteristic measurement apparatus according to this embodiment. It is a figure for demonstrating the measurement method of the optical characteristic using the optical characteristic measurement system shown in FIG. It is a schematic diagram which shows the apparatus configuration of the data processing apparatus which comprises the optical characteristic measurement system shown in FIG. It is a schematic diagram which shows the apparatus configuration of the measuring apparatus which comprises the optical characteristic measurement system shown in FIG. It is a graph which shows the result of having evaluated the influence of the temperature drift of the measuring apparatus shown in FIG. It is a schematic diagram which shows the main part of the apparatus structure of the optical property measurement system suitable for the measurement of quantum efficiency. It is a flowchart which shows the procedure of the measurement method using the measuring apparatus according to this embodiment. It is a figure which shows the measurement example at the time of generating singlet oxygen from _{fullerene (C 60} ) in a solvent by using the optical characteristic measurement system shown in FIG. It is a flowchart which shows the procedure for calibrating the optical characteristic measurement system according to this Embodiment. It is a schematic diagram for demonstrating the procedure for performing calibration with respect to the optical characteristic measurement system according to this embodiment.

Embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals and the description thereof will not be repeated.

<A. System configuration example>
First, an optical characteristic measurement 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 view showing a configuration example of an optical characteristic measurement system 1 including an optical characteristic measurement device according to the present embodiment.

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

The optical characteristic measurement system 1 shown in FIG. 1 can measure various optical characteristics. Optical characteristics include, for example, total luminous intensity, illuminance (or spectral radiance), brightness (or spectral radiance), luminosity, color reproduction (chromaticity coordinate, stimulation purity, correlated color temperature, chromaticity), 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 having a predetermined wavelength (typically, light in the ultraviolet to visible range), and fluorescence generated from the sample (typically). The case of detecting light in the near-infrared region to the infrared region) will be illustrated. In this case, the optical properties to be measured typically include the spectrum and quantum efficiency of fluorescence emanating from the sample.

The light source 4 generates excitation light to irradiate 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 a 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 spread in the wavelength band (when a white light source such as a xenon discharge lamp is adopted), a wavelength band transmission filter for selecting the desired monochromatic light may be provided.

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

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

With reference to FIG. 2A, the integrator 6 forms a hemispherical integrator space within it. More specifically, the integrator 6 is a disk-shaped light diffuse reflection layer arranged so as to pass through the hemisphere portion 61 and the substantially center of curvature of the hemisphere portion 61 and close the opening of the hemisphere portion 61. Planar mirror 6 including 62a
Consists of 2. The light diffusion reflection layer 61a is provided on the inner surface (inner wall) of the hemisphere portion 61. The light diffuse reflective layer 61a is typically formed by applying or spraying a light diffusing material such as barium sulfate or PTFE (polytetrafluoroethylene). The flat mirror 62 has a light diffusion reflection layer 62a that mirror-reflects (regular reflection and diffuse reflection) on the inner surface side of the hemisphere portion 61. By arranging the light diffuse reflection layer 62a of the plane mirror 62 toward the inside of the hemisphere portion 61, a virtual image of the hemisphere portion 61 is generated. By combining the space (real image) defined inside the hemisphere portion 61 and the virtual image generated by the plane mirror 62, it is possible to obtain substantially the same illuminance distribution as when a global 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 portion 61. The sample SMP1 is attached to the sample window 65 so that the fluorescently emitting substance is exposed inside the hemisphere portion 61.

The excitation light generated by the light source 4 propagates through the optical fiber 5 and is irradiated to the sample SMP1 arranged inside the integrator 6 through the light projecting optical system 50. The projectile optical system 50 includes a condensing lens 52, and condenses the excitation light from the light source 4 onto the sample SMP1. The plane mirror 62 is formed with a projection window 64 for guiding the excitation light into the inside of the integrator 6.

The light (typically fluorescence) generated by the sample SMP1 in response to the excitation light is repeatedly reflected inside the integrator 6 to make the illuminance appearing on the inner surface of the integrator 6 uniform.

The flat mirror 62 is formed with an observation window 67 for observing the illuminance on the inner surface of the integrator 6, and a light extraction unit 68 is provided in association with the observation window 67. An end portion of an optical fiber 7 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 of the inner surface of the integrator 6 (corresponding to the visual field range seen from the observation window 67) is incident on the measuring device 100. The measuring device 100 measures the optical characteristics of the sample SMP1 and the like from the light observed through the optical fiber 7.

As shown in FIG. 2A, since the user only needs to mount the sample SMP1 on the sample window 65 provided at the apex (lowermost part in the drawing) of the hemisphere portion 61, it is necessary to measure a plurality of sample SMP1s. Even if there is, the work of mounting and exchanging the sample can be simplified.

When measuring the sample SMP2 which is a solution sample with reference to FIG. 2B, the sample holder 63 is attached to the sample window 66 formed at the center of the plane mirror 62, and the sample is contained in the sample holder 63. SMP2 is placed. At this time, the standard reflection member 69 is attached to the sample window 65 formed in the region including the apex of the hemisphere portion 61.

The projection 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 projection optical system 50 irradiates the sample SMP2 with the excitation light from the light source 4 through the inside of the sample holder 63. The light (typically fluorescence) generated by receiving the excitation light of the sample SMP2 is repeatedly reflected inside the integrator 6, so that the illuminance appearing on the inner surface of the integrator 6 becomes uniform. The measuring device 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. 2A.

In the usage state shown in FIG. 2 (B), the standard reflective member is also attached to the floodlight window 64 (see FIG. 2 (A)).

Re-excited fluorescence emission may occur depending on the material or characteristics of the sample. The re-excitation fluorescence emission is a phenomenon in which the excitation light reflected on the surface of the sample is diffusely reflected in the integrator 6 and then incident on the sample again to generate further emission. In the optical characteristic measurement system 1, it is also possible to correct such an error due to re-excited fluorescence emission.

With reference to FIG. 1 again, the measuring device 100 receives the light observed through the optical fiber 7 and outputs a measurement result (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 implemented by a general purpose computer. FIG. 3 is a schematic view showing an apparatus configuration of a data processing apparatus 200 constituting the optical characteristic measurement system 1 shown in FIG. The data processing device 200 is a CPU (Central Processing Unit) 202 that executes various programs including an operating system (OS).
A main memory 204 for temporarily storing data necessary for executing a program on the CPU 202, and a hard disk 206 for non-volatilely storing a program executed on the CPU 202 are included. The components constituting the measuring device 100 are communicably connected to each other via the bus 220.

The hard disk 206 stores in advance a measurement program 208 for realizing the measurement method according to the present embodiment. Such a measurement program 208 is an example of a recording medium by means of a CD-ROM (Compact Disk-Read Only Memory) drive 210.
-Read from ROM212 or the like. That is, the measurement program 208 for realizing the measurement method according to the present embodiment is stored in a recording medium such as a CD-ROM 212 and distributed. Alternatively, the measurement program 208 may be distributed via the 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 the measurement result and the like to the user. The input unit 218 typically includes a keyboard, a mouse, and the like, and accepts user operations.

In addition, a part or all of the above-mentioned 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. Discovery of new issues>
It is assumed that the sample is irradiated with excitation light having a wavelength component in the ultraviolet region or the visible region, and the light emission generated by the sample is measured. In such a measurement, the light produced by the sample is often extremely weak with wavelength components in the near-infrared region to the infrared region. In addition, some samples have a short life and can secure only a short measurement time.

Therefore, it is preferable to use a measuring device having as high a detection sensitivity as possible. As in the prior art, a method of increasing the detection sensitivity by cooling the detection element using liquid nitrogen or the like is known, but it takes a long time to set up and is not easy to handle. is there.

Therefore, realizing a measuring 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 room temperature is provided with a function of maintaining a constant temperature of the detection element itself in order to avoid disturbance due to temperature.

When the inventors of the present application increase the detection gain of the detection element in order to detect extremely weak light, the ambient temperature of the measuring device is raised even though the temperature of the detection element itself is kept constant. I found a new challenge of being affected. According to the diligent research of the inventors of the present application, the temperature changes inside the measuring device as the ambient temperature of the measuring device changes, and the detection element having increased gain also changes the radiant heat due to the temperature change. As a result, I came to the conclusion that even though the intensity of the light to be measured has not changed, the measurement result will have an error due to its influence. Therefore, the inventors of the present application have invented the measuring device 100, which employs a function of not causing the influence of the temperature change generated inside the measuring device, that is, the influence of radiant heat, in addition to the detection element itself. According to the measuring device 100 according to the present embodiment, stable measurement is possible even if the ambient temperature of the measuring device 100 changes.

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

FIG. 4 is a schematic view showing an apparatus configuration of the measuring apparatus 100 constituting the optical characteristic measuring system 1 shown in FIG. With reference to FIG. 4, the measuring device 100 is a spectroscopic receiver and includes an optical slit 104, a concave diffraction grating 106, and a detection element 108. These components are arranged inside the housing 102.

A connecting member 116 for mounting the end portion of the optical fiber 7 is provided in a part of the housing 102. The optical axis at the open end of the optical fiber 7 is aligned with the central axis of the optical slit 104 by the connecting member 116. The 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 is incident on the concave diffraction grating 106, each wavelength component contained in the measurement light is optically separated. That is, when the measurement light is diffracted by the concave diffraction grating 106, each wavelength component included in the measurement light travels in different directions according to the length of the wavelength. Each wavelength component is incident on the detection element 108 optically aligned with respect to the concave diffraction grating 106. In this way, 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 this configuration example, the near-infrared region to the infrared region) to the detection element 108. There is.

As the detection element 108, an array sensor in which a plurality of detection surfaces independent of each other are arranged side by side is adopted. As the detection element 108, a CCD (Charge-Coupled Device) image sensor may be adopted. 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 at least partially joining the detection element 108 to cool the detection element 108. The detection element 108 is a self-cooling type detection element, and by reducing thermal noise and reducing dark current (dark current), the detection sensitivity is increased and the S / N (Signal to Noise) ratio is improved. It is configured to let you. 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 adopted inside the base 110.

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

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 or the like so that the detection element 108 is maintained at a predetermined temperature based on a detection value from a temperature sensor or the like (not shown).

In the measuring device 100 according to the present embodiment, in addition to the cooling function of the detection element itself, a function of not affecting the detection element 108 due to the change of radiant heat is implemented. That is, the measuring device 100 has a function and a configuration of suppressing a temperature change occurring around the detection element 108 in the housing 102. In the configuration example shown in FIG. 4, an example in which a temperature control function for maintaining a constant temperature in the internal space of the housing 102 and a heat insulating function for reducing heat intrusion into the housing 102 is shown. ..

The temperature control function is realized by a cooling mechanism that is at least partially bonded to the housing 102 and releases the 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 the side surface of the housing 102 and a heat radiating plate 132 joined to the electronic cooling element 130. The electronic cooling element 130 includes a Peltier element or the like, and a current value or the like is controlled by a cooling controller 134.

Inside the heat radiating plate 132, a flow path (not shown) through which a refrigerant (typically water or chlorofluorocarbon) 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 heat dissipation 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 from the heat radiating plate 132 to the outside, and the heat is exchanged with the refrigerant in the heat radiating plate 132, so that the circulation path by the refrigerant circulation pump 136 It is released to the outside above. That is, the heat dissipation plate 132 and the refrigerant circulation pump 136 promote the 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 refrigerant circulation pump 136 and the heat radiating plate 132 is illustrated, but the configuration uses cooling fins instead of the heat radiating plate 132 as in the self-cooling function of the detection element 108. May be adopted.

The heat insulating function is arranged around the housing 102, and is realized by a structure for suppressing heat intrusion from the periphery of the housing 102 into the housing 102. More specifically, as a heat insulating function, the heat insulating material 120 is arranged on the outer periphery of the housing 102. As the heat insulating material 120, any material can be used, but for example, fiber-based heat insulating materials such as glass wool and rock wool may be used. Alternatively, foam-based heat insulating materials 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 intrusion from the surroundings into the inside of the housing 102.

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

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

As another configuration example, heat intrusion from the ambient temperature may be reduced by providing a vacuum layer on the outer peripheral side or the inner peripheral side of the housing 102 instead of the heat insulating material 120. Alternatively, the temperature inside the housing 102 may be maintained constant by circulating a temperature-controlled refrigerant (typically, dry air, nitrogen, etc.) around the housing 102.

Further, two or more functions may be appropriately combined among the plurality of functions described above.
The measuring device 100 according to the present embodiment detects by stabilizing the temperature inside the housing 102 in which the detection element 108 is arranged, based on the new knowledge of the inventors of the present application as described above. 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 of suppressing temperature changes that occur around the detection element 108 in the housing 102, the dark output is stabilized by masking the part of the detection surface of the detection element 108 that is not used for measurement. It can also improve sex.

<D. Improvement effect>
Next, the effect of improving the temperature drift in the measuring device 100 shown in FIG. 4 will be described. FIG. 5 is a graph showing the result of evaluating the influence of the temperature drift of the measuring device 100 shown in FIG. FIG. 5 includes the measuring device 100 shown in FIG. 4, the temperature control function (electronic cooling element 130, heat dissipation plate 132, cooling controller 134, refrigerant circulation pump 136) and heat insulating function (heat insulating material 120) shown in FIG. This is the result of evaluating the change in the output value when the ambient temperature is changed by arranging each of the measuring devices (comparative examples) that are not used in the constant temperature bath.

The “ambient temperature” shown in FIG. 5 indicates the temperature change in the constant temperature bath. Specifically, the temperature was changed stepwise by 5 ° C. every 2 hours in the range of 10 ° C. to 30 ° C.

Regarding the measuring device of the comparative example, the one in which the detection sensitivity of the detection element is standardized ((1) standard sensitivity in FIG. 5 (comparative example)) and the one in which the detection sensitivity of the detection element is set to be high (FIG. 5). (2) High sensitivity (comparative example)) and two types were measured. On the other hand, the measuring 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 is shown in a state where the incident of the measurement light is blocked. 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 the smaller the value, the more preferable.

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

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

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

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

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

The optical characteristic measuring system 1A includes a branched fiber that branches the light from the measurement target and guides the light to the measuring device 100 and the measuring device 100A, respectively. That is, the optical fiber 7 connected to the optical extraction unit 68 of the integrator 6 is divided into an optical fiber 71 connected to the measuring device 100A and an optical fiber 72 connected to the measuring device 100 at the branching unit 73. .. That is, the light observed through the optical fiber 7 is separated into two and incident on 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 in 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 from the near infrared region to the infrared region. That is, the measuring device 100A is mainly configured to have detection sensitivity for wavelength components in the near infrared region or the infrared region, and the measuring device 100 is configured to have at least a part of 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 shown in FIG. 4 may be adopted, but when the excitation light is measured, the intensity of the light to be detected is high. , The temperature control function (electronic cooling element 130, heat dissipation plate 132, cooling controller 134, refrigerant circulation pump 136) and heat insulating function shown in FIG. 4 are not necessarily provided. In the optical characteristic measurement system 1A shown in FIG. 6, a measuring device 100A omitting the temperature control function and the heat insulating function is adopted.

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

Further, the detection element 108 of the measuring device 100A is set so that the detection sensitivity is higher than that of the detection element 108 of the measuring device 100. In other words, the measuring device 100 is configured to have a lower detection sensitivity than the measuring device 100A.

According to the optical characteristic measurement system 1A shown in FIG. 6, since the two measuring devices can measure in parallel, the spectrum from the ultraviolet region to the near infrared region (or the infrared region) can be measured at the same time. For example, as a function for measuring a spectrum from an ultraviolet region to a near infrared region (or an infrared region) with one measuring device, a diffraction grating is mechanically sequentially rotated to sequentially change the wavelength to be detected. Those (ie, sweeping wavelengths) are known. 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. Further, when the measurement in the ultraviolet region and the visible region is completed and the measurement shifts to the measurement in the near infrared region or the infrared region, a mechanical switching operation is required, which may cause instability in measurement.

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

<F. Measurement method>
Next, a measuring method using the measuring device 100 shown in FIG. 4 will be described. When the measuring device 100 and the measuring device 100A are used as in the optical characteristic measuring system 1A shown in FIG. 6, the measurement can be performed by the same procedure.

FIG. 7 is a flowchart showing a procedure of a measurement method using the measuring device 100 according to the present embodiment. With reference to FIG. 7, the user first powers on and ages each component of the optical property measurement system (step S100). Specifically, 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 arranges the reference in the integrator 6 so 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, and in the case of a solution sample, a container of the same type as the container in which the sample is sealed is filled with only the solvent. The measuring device 100 measures the light when the reference is irradiated with the excitation light (step S104). This measured value is a value indicating 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 arranges the sample in the integrator 6 so that the excitation light from the light source 4 is directly applied to the sample (step S106). The measuring device 100 receives the excitation light and measures the light generated from the sample (step S108). At this time, the measuring device 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 a setting for correcting the re-excited fluorescence emission (step S110). The measuring device 100 receives the excitation light and measures the light generated from the sample (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 placed 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 provided. Measure the light generated when the sample is irradiated with. In the case of a solution sample, the standard reflective member 69 mounted on the sample window 65 of the integrator 6 is removed, and the measurement is performed in a state where the excitation light transmitted through the sample is not reflected in 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 sample. (For example, quantum efficiency, etc.) is calculated (step S114).

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

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

As shown in FIG. 8 (A), the spectrum of the generated fluorescence cannot be measured in the state where the detection sensitivity of the detection element is standardized, but as shown in FIG. 8 (B), the detection sensitivity of the detection element is measured. It can be seen that the spectrum of the generated fluorescence can be measured in the raised state.

Furthermore, the internal quantum efficiency of fullerenes in the solvent was measured using the optical property measurement system 1A shown in FIG. The re-excited fluorescence emission is also corrected. In order to examine the stability of the measurement, the same measurement was repeated for 3 days on the same sample (measurement was performed once a day for a total of 3 times). The results are shown below.

・ Day 1: 0.061%
・ Day 2: 0.062%
・ Day 3: 0.062%
According to the measurement result of this 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 measurement system 1A shown in FIG. 6 includes two measuring devices 100 and 100A having different detection sensitivities. Considering the measurement of quantum efficiency, it is necessary to perform energy calibration using the same standard light source. That is, it is necessary to match the magnitude of 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 measuring devices using the same standard light source. Therefore, an example of a calibration method for the measuring devices 100 and 100A for calibrating the optical characteristic measuring system 1A according to the present embodiment will be described.

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

With reference to FIGS. 9 and 10, first, for the standard lamp 150 used for calibration, a pre-calibrated upper standard light source (international standard traceable light source) is used, and a value such as illuminance is used at a distance L1. The attachment is performed (step S200). It is assumed that the standard lamp 150 is, for example, a light source of 50 W. In step S200, the energy value for the standard lamp 150 is acquired. Energy values are typically defined using spectral irradiance [μW · cm ^-2 · nm ^-1].

Subsequently, the standard lamp 150, which is a light source to which the energy value is priced in advance, 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 with their optical axes aligned and separated by a distance L1 (step S202). In order to reduce the influence of stray light components and the like generated from the standard lamp 150, shading 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, the energy calibration coefficient for the measuring device 100A is calculated based on the output value from the measuring device 100A under the installation conditions shown in FIG. 10A (step S204).

The energy calibration coefficient is a coefficient that converts the output value (signal value) from the measuring device into energy, and has a relationship of energy = output value after dark correction (measured value-measured value at the time of dark correction) / energy calibration coefficient. is there.

In step S204, the 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 the energy value priced for the standard lamp 150. Calculated by dividing. That is, the energy calibration coefficient k2 = (I2-Id2) / (valued energy value E1 of the standard lamp 150) of the measuring device 100A.

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 standard lamp 150 and the measuring device 100A (standard sensitivity) are brought close to each other from the distance L1 to the distance L2, and then between the standard lamp 150 and the measuring device 100A. The dimming mesh 156 is arranged on the optical axis (step S206). As the dimming mesh 156, for example, a mesh having a transmittance of 1% (that is, dimming to 1/100) can be adopted. The reason why the distance L1 is brought closer to the distance L2 is to weaken the degree of dimming of the dimming mesh 156, and if a more appropriate dimming mesh 156 can be prepared, it is not necessary to change the distance.

Then, based on the output value obtained by receiving the light from the standard lamp 150 with 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 conditions is calculated. decide. That is, based on the output value from the measuring device 100A under the installation conditions shown in FIG. 10B, the converted value of the energy of the standard lamp 150 reflecting the dimming mesh 156 and the distance L2 is calculated (step S208). .. Specifically, the 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. Then, the converted energy value E2 is calculated. That is, the converted energy value E2 = (I2'-Id2) x energy calibration coefficient k2.

Subsequently, the standard lamp 150, which is a light source, and the measuring device 100 are arranged according to the other installation conditions. As an example, in the state shown in FIG. 10B, the measuring device 100 (high sensitivity) is replaced with the measuring device 100A (standard sensitivity) while maintaining the arrangement state of the shading plate units 152 and 154 and the dimming mesh 156. (See FIG. 10C) (step S210).

Then, based on the output value obtained by receiving the light from the standard lamp 150 by the measuring device 100 and the converted value of the energy of the standard lamp 150 corresponding to the installation condition of FIG. 10B, the measuring device 100 Determine the energy calibration factor for. That is, the energy calibration coefficient for the measuring device 100 is calculated based on the output value from the measuring device 100 under the installation conditions shown in FIG. 10 (C) (step S212). In step S212, the 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).

By the above procedure, the energy calibration coefficient for each of the measuring device 100 and the measuring device 100A can be determined by 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, etc. 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 as appropriate.

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

Further, since the measuring device 100A according to the present embodiment employs a method of cooling the detection element 108 itself and the inside of the housing 102 by using an electronic cooling element, a method of cooling by using liquid nitrogen or the like is adopted. Compared with, the measurement time including aging can be significantly shortened.

According to the optical characteristic measuring system 1A according to the present embodiment, the light from the measurement target can be simultaneously measured by using the measuring device 100 and the measuring device 100A having different detection ranges. Both the measuring device 100 and the measuring device 100A use an array sensor (as an example, a CCD image sensor) as a detection element, and can acquire the intensities of a plurality of wavelength components at once. As a result, the 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 method of sweeping the wavelength.

Further, by optimizing the detection sensitivities of the measuring device 100 and the measuring device 100A, it is possible to measure extremely weak light stably and with good reproducibility without being affected by changes in the surrounding environment. Therefore, it is possible to measure the quantum efficiency with high accuracy. By adopting such a device configuration, for example, it is possible to detect fluorescence having a wavelength component in the near infrared region where a substance in a living body is generated. It can also be applied to the development of various materials. Furthermore, it can be applied to the field of energy development such as synthesizing and using artificial light.

The above description will clarify the other advantages of the optical property measuring device and the optical property measuring system according to the present embodiment.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims, not the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1,1A optical characteristic measurement system, 2 system body, 4 light sources, 5,7,71,72
Optical fiber, 6 integrator, 50 floodlight optical system, 52 condenser lens, 61 hemisphere, 61a diffuse reflection layer, 62 plane mirror, 62a diffuse reflection layer, 63 sample holder, 64 floodlight window, 65,66 Sample window, 67 Observation window, 68 Light extraction section, 69 Standard reflector, 73 Branch section, 100, 100A measuring device, 102 housing, 104 Optical slit, 106 Concave diffraction grid, 108 detection element, 110 base, 111, 130 Electronic cooling element, 112 cooling fins, 113 junction layer, 114,134 cooling controller, 116
Connection member, 120 insulation, 132 heat dissipation plate, 136 refrigerant circulation pump, 138,139 refrigerant path, 150 standard lamp, 152,154 shading plate unit, 156 dimming 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 inputs, 220 bus.

Claims (5)

An optical fiber for guiding light in the housing of the sample disposed outside the casing occurs,
The detection element arranged inside the housing and
A diffraction grating that guides the light from the sample to the detection element,
A cooling mechanism that cools the detection element by joining it at least partially to the detection element.
A temperature control mechanism for maintaining a constant temperature in the internal space of the housing,
It is arranged around the housing and includes a heat insulating mechanism for reducing heat intrusion from the periphery of the housing into the housing.
The cooling mechanism
A base portion for forming a part of the housing and supporting the detection element, and
A first electronic cooling element arranged inside the base,
An optical measuring device including cooling fins bonded to the outer surface of the base via a bonding layer. The optical measuring device according to claim 1, wherein the temperature control mechanism includes a mechanism that at least partially joins the housing and releases heat inside the housing to the outside of the housing. The temperature control mechanism
A second electronic cooling element that is at least partially bonded to the housing,
A heat radiating plate bonded to the second electronic cooling element and
The optical measuring device according to claim 2, further comprising a refrigerant circulation pump that circulates a refrigerant through a path including the heat dissipation plate. The optical measuring device according to any one of claims 1 to 3, wherein the heat insulating mechanism includes one of a heat insulating material and a vacuum layer. The optical measuring device according to any one of claims 1 to 3, wherein the heat insulating mechanism includes a mechanism for circulating a temperature-controlled refrigerant around the housing.

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