JP2013013547A - Optical measurement apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical measurement apparatus enabling measurement in an optimal condition without additional calibration even when probes are replaced or exchanged.SOLUTION: The optical measurement apparatus emits light to an object 10 from a light source probe 1, and detects transmitted light with a light-receiving probe 2 to measure the intensity variation so as to measure internal information on the object. The apparatus has a probe holder 3, and is structured as follows: the light source probe and the light-receiving probe are attached to the probe holder so as to be individually detached therefrom; each of the light source probe and the light-receiving probe has a nonvolatile memory which stores data for calibration on light source elements each arranged in the light source probe and light-receiving elements arranged in the light-receiving probe, and numbers uniquely allocated to the probes. The device determines positions of the probes in the probe holder so as to adjust drive current of the light source elements in each of the probes, and so as to correct sensitivity of the light-receiving elements based on each of independent calibrated data on the probes.

Description

  The present invention relates to an optical measurement device such as a biological light measurement device that irradiates a measurement target with light, detects light transmitted through the measurement target, and measures its internal information.

  As a biological light measurement device, a measurement device called an optical topograph device is known. This device measures biological information, for example, changes in blood flow, by arranging a number of light source probes that emit light and light receiving probes that receive light in a living body measurement object and measuring differences in light transmission. It is a device to do.

  Since the light source probe and the light receiving probe are arranged with a predetermined distance between the probes on the measurement object, each probe is attached to a probe folder that can be arranged within a predetermined distance, and the probe folder is arranged on the skin to be measured. Measure. Since the surface of the living body has irregularities and curved surfaces, the probe folder has a flexible structure so that the tip of each probe contacts the skin uniformly. When measuring the distribution of biological information, attach a probe folder with many light source probes and light receiving probes so that they are in close contact with the measurement site, for example, the head, and irradiate each infrared source with near infrared rays. Measure with a probe.

  In order to measure the distribution of biological information, each light source probe needs to have the same light output so that there is no variation between the probes. Similarly, when each light receiving probe detects the same light, it must be detected as the same value. However, the light source element used for the light source probe and the light receiving element used for the light receiving probe have individual variations. Normally, the input / output characteristics of the element are measured in advance and the calibration data is recorded. When each light source element and light receiving element are incorporated in the measurement system, the driving current of the light source element and the light receiving element The measurement data is unified by correcting the sensitivity correction by the adjustment unit of the control circuit. In addition, since the input / output characteristics of each light source element and light receiving element change depending on the environmental temperature of the element and the usage time of the element, it is necessary to correct the temperature of each element in advance and periodically revise the calibration data. As a method for obtaining a constant output from a light source element, Patent Document 1 discloses that a light receiving element is provided inside a light source probe, a part of output light from the light source element is guided to the light receiving element inside the probe, and an output of the light receiving element is obtained. There is a description of a method for performing feedback so that is constant.

JP 2008-178563 A

  In the conventional measurement system, circuit adjustment and measurement correction in the measurement program are performed based on calibration performed in advance, so if you replace the probe or the probe you used does not work, and you install a different probe, It was necessary to measure the calibration value and input the correction value in the measurement program again.

  An object of the present invention is to provide an optical measurement device that can perform measurement under optimum conditions without performing calibration again even if the probe is replaced or replaced.

  The present invention assigns a unique number to each probe, has a non-volatile memory in each probe, and records and holds the probe unique number and calibration data of the optical element, so that there are a plurality of probe for holders at the time of measurement. It is possible to grasp which probe is arranged at the probe port and set the optimum optical element driving condition based on the calibration data.

  A typical example of the invention disclosed in the present application is to irradiate a measurement target with light from a light source probe, detect the light transmitted through the measurement target with a light receiving probe, and measure the intensity change of the light. Thus, in the optical measurement device for measuring the internal information of the measurement target, the optical measurement device has a probe folder, and the light source probe and the light receiving probe are attached to the probe folder so that they can be individually detached, and the light source probe and The light receiving section lobe can hold a light source element disposed in the light source probe, calibration data for the light receiving element disposed in the light receiving probe, and a number uniquely assigned to each probe. When measuring, determine where the probe is mounted in the probe folder and Wherein those configured to perform adjustment or sensitivity correction of the light-receiving element of the driving current of light source elements of each probe based on the individual calibration data that is held in the nonvolatile memory.

  According to the present invention, even when each probe is attached to any probe port of the probe folder or when the probe is replaced, measurement can be performed under optimum conditions without performing calibration again.

It is the figure which showed the whole structure of the optical measuring device of Example 1 of this invention. It is the figure which showed the light source probe of Example 1 of this invention. It is the figure which showed the light reception probe of Example 1 of this invention. It is the figure which showed the probe folder of Example 1 of this invention. It is the expanded view which showed the probe folder of Example 1 of this invention. It is explanatory drawing which showed the measurement procedure of Example 1 of this invention. It is the figure which showed the probe calibration unit which performs probe calibration. It is explanatory drawing which showed the calibration procedure of the light source probe. It is explanatory drawing which showed the measurement relationship of the drive current of a light source element, and the output voltage of a calibrated photodetector. It is explanatory drawing which showed the graph obtained from the approximate expression of the drive current and light output of a light source element. It is explanatory drawing which showed the calibration procedure of the light reception probe. It is explanatory drawing which showed the measurement relationship of the light output by a calibrated light source, and the light reception output of a light receiving element. It is explanatory drawing which showed the graph obtained from the approximate expression of a light output and the light reception output of a light receiving element. It is the figure which showed the whole structure of the optical measuring device of Example 2 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing, the same number is attached | subjected to the same component, and repeated description is abbreviate | omitted.

  With reference to FIGS. 1 to 13, the optical measurement apparatus according to the first embodiment will be described in detail. The optical measurement apparatus according to this embodiment uses the fact that when a part of the brain is active, the blood volume for sending oxygen to the part increases, the local blood dynamics in the living body. It is a device that measures changes. Specifically, near-infrared light is irradiated from the scalp, and by measuring the scattering of this near-infrared light by hemoglobin in the blood, the change in the blood volume near the surface of the cerebrum is measured. The function of the brain can be easily observed by displaying it on a dimensional map or the like. Here, near-infrared light is an electromagnetic wave having a wavelength longer than that of visible light.

  First, FIG. 1 is a perspective view showing the entire optical measurement system. The measurement system consists of an optical measurement device and a calibration device.

  The optical measurement device measures a change in blood volume to be measured. The optical measuring device includes a system controller 5, a measuring unit 4, a probe folder 3, a light source probe 1, and a light receiving probe 2. The probe folder 3 and the measurement unit 4 are connected via a measurement unit-probe folder connection cable 7. The measurement unit 4 and the system controller 5 are connected via a system controller-measurement unit connection cable 8. A light source probe 1 and a light receiving probe 2 are attached to the probe folder 3 for measurement. In order to measure the blood change of the measurement object 10, the measurement is performed by placing the probe unit 3 equipped with each probe on the skin of the measurement object. In that case, it arrange | positions so that the optical fiber edge part arrange | positioned at the front-end | tip of each probe may contact uniformly.

  The calibration device calibrates the light source probe 1 and the light receiving probe 2. The calibration apparatus includes a system controller 5 and a probe calibration unit 6. The probe calibration unit 6 and the system controller 5 are connected via a system controller-probe calibration unit connection cable 9.

  FIG. 2 is a diagram showing the configuration of the light source probe. In the figure, (a) is a perspective view of the light source probe 1, (b) is a cross-sectional view of the light source probe, and (c) is a broken surface 47 of the cross-sectional view. The light source probe 1 includes a light source element 11, an optical filter 12, an optical fiber 13, a probe connector (probe side) 14, a processor electric circuit board 16, a processor element 17, a nonvolatile memory 18, a light source element driving electric circuit board 15, and a light source element driving. The circuit electronic component 19 is configured. A unique number is assigned to each light source probe and is recorded in the nonvolatile memory 18. The non-volatile memory 18 stores individual calibration data of the light source elements, which are read out from the system controller at the time of measurement, and optimal driving conditions for the light source elements are set. Information in the nonvolatile memory 18 is read and written via the processor element 17. The processor element 17 transmits and receives information via the probe connector 14.

  FIG. 3 is a diagram showing the configuration of the light receiving probe. In the figure, (a) is a perspective view of the light receiving probe 2, (b) is a sectional view of the light receiving probe, and (c) is a broken surface 48 of the sectional view. The light receiving probe 2 includes a light receiving element 20, an optical filter 12, an optical fiber 13, a probe connector (probe side) 14, a processor electric circuit board 16, a processor element 17, a nonvolatile memory 18, a light receiving element driving electric circuit board 21, and a light receiving element driving. The circuit electronic component 22 is configured, and each light receiving probe is assigned a unique number and recorded in the nonvolatile memory 18. The non-volatile memory 18 stores individual calibration data of the light receiving element, which is read from the system controller at the time of measurement, and an optimum driving condition of the light receiving element is set. Information in the nonvolatile memory 18 is read and written via the processor element 17. The processor element 17 transmits and receives information via the probe connector 14.

  FIG. 4 is an explanatory view showing the probe folder 3. The probe folder 3 has a plurality of probe ports 23 for mounting probes. A probe connector (folder side) 24 that is connected to the probe connector (probe side) 14 when the probe is mounted is disposed beside the probe port. A connector cover 25 is provided on the probe connector (folder side). The probe control interface unit 27 has a probe control circuit for controlling the connected probe in the probe folder. The probe control circuit is connected to the folder connector 26, and the probe folder 3 and the measurement unit 4 are connected by a measurement unit-probe folder connection cable 7.

  5A and 5B are diagrams showing the probe folder, where FIG. 5A is an overall perspective view and FIG. 5B is a developed view. The probe folder 3 includes a connector layer 24, a probe folder upper layer 28, a connector wiring layer 29, and a probe folder lower layer 30 from the top. The probe folder upper layer 28 and the probe folder lower layer 30 serve to electrically insulate the connector wiring 29. The probe folder upper layer 28, the connector wiring layer 29, and the probe folder lower layer 30 are integrally formed.

  FIG. 6 is a flowchart showing the measurement procedure. When measuring a blood change amount to be measured, a probe folder, a light receiving probe, and a light source lobe that cover the measurement region are prepared according to the measurement purpose. If the prepared probe is not calibrated, each probe is calibrated (S601, S602). Next, the probe folder is attached to the measurement target (S603). Next, the light source probe and the light receiving probe are attached to the probe port of the probe folder in accordance with the measurement (S604, S605). Next, the probe folder and the measurement unit are connected by the measurement unit-probe folder connection cable (S606). Next, the measurement unit and the system controller are connected by the system controller-measurement unit connection cable (S607), and the measurement connection arrangement is arranged. The system controller confirms the mounting position by confirming which probe is connected to which probe port of the plurality of probe folders and which probe unique number for each probe port (S608). When the probe arrangement suitable for the measurement purpose can be confirmed, the calibration parameters of each probe are read, and the optimum probe control setting for the measurement procedure is performed (S609). Then, after confirming probe mounting and adjusting the output of the light source probe (S610), measurement is performed according to the measurement sequence (S612).

  In the measurement adjustment performed by the system controller with the measurement connection arrangement in place, first, it is confirmed by performing electrical communication to each port to determine whether the probe is connected to each probe port. If the connection is confirmed, the individual number recorded in the connected probe and the type of the probe are read. If the probe is a light source probe, the light source drive current-light output characteristic function, cumulative drive time Is read out. On the other hand, in the case of the light receiving probe, the characteristic function of the received light intensity-sensor output voltage and the accumulated measurement time are read out. If the connection state of all the probe ports in the probe folder is confirmed, the mounting state of the probe to the measurement target is checked by the measurement sequence determined by the arrangement pattern of the probes connected to each probe port. Here, when the probe arrangement is not in the pre-programmed measurement sequence, a sequence program is newly input to the system controller, or the probe arrangement is changed to an arrangement suitable for the sequence program.

  To check the mounting state of the probe on the measurement target, first, the driving current of the light source probe is set to the average driving current of each probe, light is emitted according to the sequence, and the light receiving intensity of the transmitted scattered light is measured by the light receiving probe. One light receiving probe separately detects light from a plurality of light source probes by time division or modulation, and measures a change in blood flow for each space determined by the positions of the light receiving probe and each light source probe pair.

  Here, the determination of the check of the mounting state on the measurement target is performed based on the received light intensity detected by the light receiving probe for the light emitted by each of the light source probes for measuring the blood flow of each light receiving probe for each space.

When the received light intensity of all the light source probes and the light receiving probe pair pattern is within the measurement allowable range, it is determined that the attachment to the subject is a measurable state.
Thereafter, the measurement preparation is completed by adjusting the output current of the light source probe so that the light reception intensity of each light source probe and the light receiving probe pair becomes the average light output, and the main measurement can be performed.

  On the other hand, if the received light intensity is greater than the allowable measurement range for all of the light source probes, it is possible to irradiate light from the outside to the light receiving probe, so check the incident of external light and check the mounting condition again. .

  If the detection intensity is lower than the allowable measurement range for all the light source probes that measure blood flow changes by space, the light receiving probe is not in contact with the measurement target. Check the wearing condition.

  Among the light source probes that measure the blood flow changes by space, if there is a pair whose detection intensity is lower than the allowable measurement range, it is expected that the light source probe is not in contact with the measurement target. Check the wearing condition again.

  Normally, the probe mounting is adjusted so that the detection intensity of all probe pairs falls within the allowable measurement range. However, even if there is a pair whose optical detection intensity does not fall within the allowable measurement range, the measurement preparation is completed and this measurement is performed. Can do. However, in that case, the measurement is performed with the pair of signals invalid.

  FIG. 7 shows a probe calibration unit for performing probe calibration, (a) is a perspective view, and (b) is a cross-sectional view. The probe calibration unit 6 includes a calibrated light source element 34, a calibrated light receiving element 35, an optical ND filter 33, an optical filter 12, an optical fiber 13, a light source element control electronic circuit 56, a light receiving element control electronic circuit 57, and a light receiving probe calibration port 32. , A light source probe calibration port 31, a light source probe connector 50, a light receiving probe connector 51, a system controller connection connector 52, a probe calibration port cover 54, and a light shielding wall 55.

  FIG. 8 is a flowchart showing the calibration procedure of the light source probe. The system controller 5 and the calibration unit 6 are connected using a system controller-probe calibration unit connection cable 9. The light source probe 1 is attached to the light source probe calibration port 31 (S801). At this time, it arrange | positions so that the optical fiber 13 arrange | positioned at the front-end | tip of a light source probe and the optical ND filter 33 for light source probe calibration may contact.

  The system controller controls the probe calibration unit electrical circuit 53 and the light source probe electronics. When the drive current of the light source element of the light source probe is gradually increased from zero (S802), and the output voltage of the calibrated photodetector is measured with the light source probe and the detection probe attached to the subject at a standard distance In addition, a current value that is a voltage output at the time of the light intensity detected by the detection probe (standard detection light intensity) is recorded as a standard drive current (S804). Furthermore, the current value is increased (S805), and the output voltage of the light detector is set to take into consideration the safety of the measurement target. The current value that becomes the output voltage of 1 / ND coefficient of the maximum light output is set to the maximum drive during measurement. The current value is recorded (S807). Then, the drive current value is increased to twice the maximum drive current value during measurement (S808). The relationship with the output voltage of the photodetector when the drive current value is changed is measured as the characteristics of the light source probe (S810). However, the measurement point is recorded in the interval from one-tenth of the standard drive current to twice the maximum drive current value during measurement. This characteristic relationship is “light source element driving current−calibrated photodetector output voltage relationship”. The number of measurement points of the current value to be recorded is a point where the current value section to be recorded is equally divided into about 200 sections. The attenuation coefficient of the light source probe calibration optical ND filter is an attenuation coefficient obtained when the light source probe and the light receiving probe are mounted on a standard measurement object at a standard distance. An approximate function is obtained from the measured measurement points (S811). The light source probe characteristic is determined from the obtained approximate function expression, and recorded in the nonvolatile memory in the probe and the storage unit of the system controller in association with the individual number of the probe (S812).

  FIG. 9 shows a “light source element driving current−calibrated photodetector output voltage relationship” obtained in the light source probe calibration procedure. This characteristic indicates the measurement relationship between the drive current of the light source element of the light source probe and the output voltage of the calibration light source probe that has passed through the ND filter.

  FIG. 10 shows a graph obtained from an approximate expression of the relationship between the driving current of the light source element and the output voltage of the calibrated photodetector.

  FIG. 11 is a flowchart showing the calibration procedure of the light receiving probe.

  The system controller 5 and the calibration unit 6 are connected using a system controller-probe calibration unit connection cable 9. The light receiving probe 2 is attached to the light receiving probe calibration port 32 (S1101). At this time, it arrange | positions so that the optical fiber 13 arrange | positioned at the front-end | tip of the light reception probe 2 and the optical ND filter 33 for light reception probe calibration may contact. The system controller 5 controls the probe calibration unit electric circuit 53 and the electronic circuit of the light receiving probe.

  The output voltage of the photodetector output by the detection probe when the drive current of the calibrated light source element is gradually increased from zero (S1102) and changed to twice the maximum drive current during measurement. Record. In addition, the output voltage at the time of the standard drive current value during that time is recorded as the standard detection light intensity, and the output voltage at the time of the maximum drive current value at the time of measurement is recorded as 1 / ND coefficient of the maximum light output intensity (S1104, S1107). The other points to be recorded are sections from the standard detection light intensity to twice the maximum light output intensity (S1110). This characteristic is “relationship between measurement of light output from calibrated light source and output voltage of light receiving probe”. Here, the drive current value of the light source element can be converted as light intensity. The number of measurement points of the current value (light intensity) of the calibrated light source to be recorded is a point where the current value (light intensity) section to be recorded is equally divided into about 200 sections. The attenuation coefficient of the light receiving probe calibration optical ND filter is an attenuation coefficient obtained when the light source probe and the light receiving probe are attached to a standard measurement object at a standard distance. An approximate function is obtained from the measured measurement points (S1111). The light receiving probe characteristic is determined from the obtained approximate function expression, and the probe individual number is assigned and recorded in the nonvolatile memory in the probe and the storage unit of the system controller (S1112).

  FIG. 12 shows a measurement (voltage value) relationship diagram of light output (current value) −light reception output by a calibrated light source. This characteristic is obtained by measuring the output voltage of the light receiving probe when receiving light that has passed through the ND filter corresponding to the attenuation coefficient when the distance between the light source probe and the light receiving probe is the standard distance. Show the relationship. From the obtained measurement data of the light output-light receiving probe output voltage, an approximate expression of light output-light receiving probe sensitivity output is obtained by a multi-order function and used as calibration data.

  FIG. 13 shows a graph obtained from the approximate expression of light output-light reception output.

  FIG. 14 shows that the probe folder 3 and the measurement unit 4 are connected using the measurement unit-probe folder connection cable 7 in the entire optical measurement system shown in FIG. Thus, the probe folder 3 and the measurement unit 4 are communicated wirelessly. By arranging the battery 60 and the wireless communication antenna 61 in the probe folder 3 and also arranging the wireless communication antenna 62 in the measurement unit 4, each probe and the measurement unit communicate with each other wirelessly. Thereby, optical measurement can be performed even while the measuring object 10 is moving or exercising.

DESCRIPTION OF SYMBOLS 1 Light source probe 2 Light reception probe 3 Probe folder 4 Measurement unit 5 System controller 6 Probe calibration unit 7 Measurement unit-probe folder connection cable 8 System controller-measurement unit connection cable 9 System controller-probe calibration unit connection cable 10 Measurement object 11 Light source element 12 Optical filter 13 Optical fiber 14 Probe connector (probe side)
15 light source element driving electric circuit board 16 processor electric circuit board 17 processor element 18 nonvolatile memory 19 light source element driving circuit electronic component 20 light receiving element 21 light receiving element driving electric circuit board 22 light receiving element driving circuit electronic component 23 probe port 24 probe connector ( Folder side)
25 Connector cover 26 Folder connector 27 Probe control interface unit 28 Probe folder upper layer 29 Connector wiring layer 30 Probe folder lower layer 31 Light source probe calibration port 32 Light receiving probe calibration port 33 Optical ND filter 34 Calibrated light source element 35 Calibrated light receiving element 47 Light source probe cross section 48 Light receiving probe cross section 50 Light source probe connector (probe calibration unit)
51 Receiving probe connector (probe calibration unit)
52 Connector for System Controller 53 Probe Calibration Unit Electrical Circuit Board 54 Probe Calibration Port Cover 55 Light-shielding Wall 56 Light Source Element Control Electronic Circuit 57 Light Receiving Element Control Electronic Circuit 60 Battery 61 Probe Wireless Antenna 62 Measurement Unit Wireless Antenna

Claims (5)

In an optical measurement device that measures internal information of a measurement target by irradiating the measurement target with light from a light source probe, detecting light transmitted through the measurement target with a light receiving probe, and measuring a change in intensity of the light. ,
Having a probe folder, the light source probe and the light receiving probe are attached to the probe folder so that they can be removed individually,
The light source probe and the light receiving section lobe hold the light source element arranged in the light source probe and the calibration data of the light receiving element arranged in the light receiving probe and the number uniquely assigned to each probe. A non-volatile memory that can
At the time of measurement, it is determined in which position of the probe folder the probe is mounted, and the adjustment of the drive current of the light source element of each probe based on the individual calibration data held in the nonvolatile memory of each probe or An optical measuring device configured to perform sensitivity correction of a light receiving element. The optical measurement device according to claim 1, further comprising:
An optical measuring device comprising a calibration unit that measures calibration data of a light source element of a light source probe and a light receiving element of a light receiving probe and writes the measured calibration data to a nonvolatile memory inside each probe. In the optical measurement device according to claim 1,
An optical measurement device, wherein the probe folder and a measurement unit are connected by a connection cable and signals are wired. In the optical measurement device according to claim 1,
An optical measurement device, wherein a battery and a wireless communication antenna are disposed in the probe folder, and a wireless communication antenna is disposed in a measurement unit to wirelessly communicate signals. In the optical measurement device according to claim 1,
The non-volatile memory of the light source probe holds a light source driving current-light output characteristic function, cumulative driving time,
An optical measuring device characterized in that the non-volatile memory of the light receiving probe holds a characteristic function of received light intensity-sensor output voltage and an accumulated measurement time.

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