WO2013161007A1 - Density calculation device and method - Google Patents

Density calculation device and method Download PDF

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Publication number
WO2013161007A1
WO2013161007A1 PCT/JP2012/060968 JP2012060968W WO2013161007A1 WO 2013161007 A1 WO2013161007 A1 WO 2013161007A1 JP 2012060968 W JP2012060968 W JP 2012060968W WO 2013161007 A1 WO2013161007 A1 WO 2013161007A1
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WO
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Prior art keywords
light
concentration
signal
laser light
laser
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PCT/JP2012/060968
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French (fr)
Japanese (ja)
Inventor
立石　潔
雅樹 郷間
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パイオニア株式会社
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Priority to PCT/JP2012/060968 priority Critical patent/WO2013161007A1/en
Publication of WO2013161007A1 publication Critical patent/WO2013161007A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/55—Specular reflectivity

Definitions

  • the present invention relates to a technical field of a concentration calculation apparatus and method for calculating a concentration of a fluid such as a blood flow.
  • concentration calculation device for example, there is a concentration calculation device that calculates the smoke concentration from the scattered light of laser light irradiated to the intake air containing smoke particles (see, for example, Patent Document 1).
  • the density calculation device disclosed in Patent Document 1 calculates a smoke density by forming a near-field pattern of laser light at an imaging position through which intake air passes using an optical system such as an imaging lens. ing.
  • concentration calculation device for example, there is a concentration calculation device that measures a sample concentration from transmitted light or reflected light of a beam irradiated on an immunochromatographic test piece (see, for example, Patent Document 2).
  • the concentration calculation device may calculate the concentration of the fluid flowing in the pipeline. Specifically, for example, the concentration calculation device may calculate the concentration of blood flow flowing in a transparent tube.
  • the calculation resolution of the concentration in other words, the calculation accuracy
  • the calculation accuracy decreases depending on the mode of irradiation of the laser beam to the pipe.
  • Such a technical problem can be particularly noticeable when the laser beam is applied to the side wall of the pipe line (that is, the side wall surrounding the flow path, which is a gap through which the fluid actually flows).
  • the present invention has been made in view of the above-mentioned problems, for example, and an object of the present invention is to provide a concentration calculation apparatus and method capable of improving the calculation resolution of the fluid concentration.
  • a concentration calculation apparatus for solving the above-described problem includes an irradiation unit that irradiates laser light to a pipe line in which a fluid flows in a flow path partitioned by a side wall, and the laser light emitted to the pipe line.
  • a light receiving unit that obtains a light reception signal by receiving light; and a calculation unit that calculates the concentration of the fluid based on the signal intensity of the light reception signal.
  • a far field pattern of the laser light is formed in a region corresponding to the flow path in the projection plane of the laser light at and along the central axis of the flow path. ) Irradiating the laser beam so that the far field pattern is not formed in a region corresponding to the side wall of the projection surface.
  • the concentration calculation method for solving the above-described problems includes an irradiation step of irradiating laser light to a pipe line in which a fluid flows in a flow path partitioned by side walls, and the laser light irradiated to the pipe line.
  • (i) in the pipe line A far field pattern of the laser light is formed in a region corresponding to the flow path in the projection plane of the laser light at and along the central axis of the flow path.
  • the laser beam is formed so that the far field pattern is not formed in a region corresponding to the side wall of the projection surface.
  • a signal (standardized light reception signal) obtained by normalizing a light reception signal acquired by the concentration calculation apparatus of the first embodiment and a signal (standardized light reception signal acquired by the density calculation apparatus of the comparative example) ( It is a graph which shows a normalization light reception signal.
  • the concentration calculation apparatus receives an irradiation unit that irradiates laser light to a pipe line in which a fluid flows in a flow path partitioned by side walls, and receives the laser light emitted to the pipe line.
  • a light receiving means for acquiring a light reception signal and a calculation means for calculating the concentration of the fluid based on the signal intensity of the light reception signal, and the irradiation means (i) While the far field pattern of the laser beam is formed in a region corresponding to the flow path in the projection plane of the laser light and along the central axis of the flow path, (ii) the projection The laser beam is irradiated so that the far field pattern is not formed on a portion of the surface corresponding to the side wall.
  • the irradiating means irradiates the pipe that is the measurement target with laser light.
  • the pipe line includes a channel that is a gap through which a fluid flows and a side wall that partitions the channel (in other words, defines the channel).
  • the side wall is typically a tubular or columnar side wall surrounding the flow path.
  • the laser light is preferably applied to the fluid flowing inside the pipe line.
  • the pipe line is transparent (including a translucent shape that allows a certain amount of laser light to pass through).
  • a transparent tube and blood are mention
  • other examples of the conduit and the fluid include blood vessels and blood.
  • a tube having a light transmissive window, a transparent tube, and a fluid flowing in the tube or the tube for example, light such as ink, oil, sewage, seasoning, etc.
  • a fluid containing at least a light absorber that absorbs light as a constituent element for example, light such as ink, oil, sewage, seasoning, etc.
  • the light receiving means receives the laser beam irradiated to the pipe line by the irradiation means.
  • the light receiving means receives laser light (so-called scattered light) scattered by at least one of the pipe and the fluid flowing in the pipe.
  • the light receiving means may receive the laser light transmitted through the pipe (so-called forward scattered light corresponding to the transmitted light) or reflected by at least one of the pipe and the fluid flowing in the pipe.
  • laser light (so-called backscattered light corresponding to reflected light) may be received.
  • a light receiving signal corresponding to the received laser light is output from the light receiving means.
  • the calculating means calculates the concentration of the fluid based on the signal intensity of the received light signal (for example, the average signal intensity or the signal intensity of the DC component included in the received signal). For example, when the light receiving means receives laser light (that is, forward scattered light) transmitted by at least one of the pipe and the fluid flowing in the pipe, the higher the concentration of the fluid (that is, the laser light) The more scatterers and the like that prevent the transmission of light, the more the fluid is contained in the fluid), the smaller the signal intensity of the received light signal. Alternatively, for example, when the light receiving means receives laser light (that is, backscattered light) reflected by at least one of the pipe and the fluid flowing in the pipe, the higher the concentration of the fluid (that is, The more scatterers etc. that reflect the laser light are contained in the fluid), the greater the signal intensity of the received light signal. The calculating means calculates the density using the relationship between the signal intensity and the density of the received light signal.
  • the signal intensity of the received light signal for example, the average signal intensity or the
  • the “fluid concentration” in this embodiment is the scatterer included in the fluid. Corresponds to concentration.
  • the irradiation means irradiates the laser beam so that a far field pattern satisfying the following conditions is formed on the projection surface of the laser beam.
  • a far field pattern is formed in a region corresponding to the flow path in the projection surface.
  • the far field pattern is not formed in the region corresponding to the side wall of the projection surface. That is, the entire far field pattern is formed in the region corresponding to the flow path on the projection surface.
  • the laser light is not irradiated on the side wall distributed in the left-right direction along the optical axis of the laser light (that is, the side wall not distributed on the optical axis of the laser light or the optical path).
  • the laser light is distributed in the front-rear direction along the optical axis of the laser light (that is, distributed on the optical axis or the optical path of the laser light).
  • the side wall may be irradiated.
  • the “projection plane” referred to here indicates a projection plane in a pipe line on which a far field pattern of laser light is formed.
  • a “projection plane” is, for example, a projection plane of laser light in a duct and a projection plane along (or parallel to) the central axis of the flow path.
  • the “projection plane” is, for example, a projection plane of laser light in the pipe and a projection plane passing through the central axis of the flow path.
  • the “projection plane” is a projection plane of the laser beam in the pipe, is a projection plane that intersects (or is orthogonal to) the optical axis of the laser beam, and is on the central axis of the flow path.
  • a projection plane along (or parallel to) or including the central axis of the flow path When laser light having an optical axis perpendicular to the central axis of the flow path is irradiated onto the pipe, the projection surface corresponds to a cross section of the pipe perpendicular to the optical axis of the laser light.
  • the laser light is irradiated onto the side wall distributed in the left-right direction along the optical axis of the laser light (that is, the side wall not distributed on the optical axis of the laser light or the optical path).
  • the side wall distributed in the left-right direction along the optical axis of the laser light that is, the side wall not distributed on the optical axis of the laser light or the optical path.
  • the irradiating means is arranged on the projection plane so that the long axis of the far field pattern extends along the direction in which the central axis of the flow path extends. Irradiate the laser beam.
  • the irradiating means can easily irradiate the laser beam so that the far field pattern is not formed in the region corresponding to the side wall of the projection surface.
  • the irradiation unit is arranged on the projection plane so that the long axis of the far field pattern is parallel to the direction in which the central axis of the flow path extends. Then, the laser beam is irradiated.
  • the irradiating means can easily irradiate the laser beam so that the far field pattern is not formed in the region corresponding to the side wall of the projection surface.
  • the irradiation unit includes the laser beam so that a central axis of a long axis of the far field pattern coincides with a central axis of the flow path on the projection plane. Irradiate.
  • the irradiating means can easily irradiate the laser beam so that the far field pattern is not formed in the region corresponding to the side wall of the projection surface.
  • the conduit is a transparent conduit that can be attached to and detached from the concentration calculation apparatus, and the fluid passes outside the living body as the measurement target. It is the blood flow of the living body that flows.
  • the irradiating means can irradiate the laser beam in the above-described manner with respect to the blood flow flowing in the transparent duct.
  • the calculation means can calculate the concentration of the blood flow flowing in the transparent duct.
  • the apparatus further includes power control means for keeping the power of the laser light at a desired level by receiving a part of the laser light emitted from the irradiation means.
  • the power control means can suitably control the power of the laser light so that the power of the laser light becomes a desired level.
  • the concentration calculation method of the present embodiment includes an irradiation step of irradiating laser light to a pipe line in which a fluid flows in a flow path partitioned by side walls, and receiving the laser light irradiated to the pipe line.
  • the irradiation step (i) the above in the pipeline While the far field pattern of the laser beam is formed in a region corresponding to the flow path in the projection plane of the laser light and along the central axis of the flow path, (ii) the projection The laser beam is irradiated so that the far field pattern is not formed on a portion of the surface corresponding to the side wall.
  • the concentration calculation method of the present embodiment may adopt various aspects.
  • the concentration calculation apparatus includes an irradiation unit, a light receiving unit, and a calculation unit.
  • the concentration calculation method of this embodiment includes an irradiation process, a light receiving process, and a calculation process. Therefore, the concentration calculation apparatus and method of the present embodiment can improve the calculation resolution of the fluid concentration.
  • the concentration calculation device is an arbitrary device that calculates the concentration of blood flowing in a blood vessel of a living body or the concentration of any fluid other than blood flowing in an arbitrary tube (for example, ink, oil, sewage, seasoning, etc.). You may apply to a density
  • FIG. 1 is a block diagram showing the configuration of the concentration calculation apparatus 1 of the first embodiment.
  • the concentration calculation apparatus 1 of the first embodiment includes a laser element 11, a light receiving element 12, an amplifier 13, and an arithmetic circuit 14.
  • the laser element 11 constitutes a specific example of “irradiation means” and irradiates the tube 100 with the laser beam LB. At this time, it is preferable that the laser element 11 irradiates the laser beam LB with respect to the flow channel 101 in the tube 100 (that is, the flow channel 101 in which blood flows).
  • the flow path 101 is surrounded by a transparent or translucent side wall 102 made of resin or glass.
  • the tube 100 is preferably attached to the concentration calculation device 1 in a detachable (in other words, replaceable) state.
  • the tube 100 may be attached to the concentration calculation device 1 in a non-detachable state.
  • the light receiving element 12 constitutes a specific example of “light receiving means”, and receives the scattered light of the laser light LB irradiated on the tube 100.
  • the scattered light received by the light receiving element 12 includes scattered light scattered by blood flowing in the tube 100 (particularly, blood cells that are moving scatterers contained in the blood) and stationary tissue ( For example, scattered light scattered by the tube 100 itself) is included.
  • the light receiving element 12 generates a received light signal obtained by converting the received scattered light into an electrical signal.
  • the amplifier 13 amplifies the light receiving signal, which is a current signal output from the light receiving element 12, after converting it into a voltage signal.
  • the arithmetic circuit 14 calculates the concentration (blood flow concentration) N of the blood flowing in the tube 100 based on the output of the amplifier 13 (that is, the light reception signal corresponding to the scattered light received by the light receiving element 12).
  • the arithmetic circuit 14 includes an LPF (Low Pass Filter) 141, an A / D converter 142, and a calculator 143.
  • the LPF 141 cuts signal components in frequency bands other than the low-frequency signal component among the signal components included in the output of the amplifier 13 (that is, the light-receiving signal corresponding to the scattered light received by the light-receiving element 12). As a result, the LPF 141 outputs a light intensity signal corresponding to a low-frequency signal component among the signal components included in the output of the amplifier 13 to the A / D converter 142.
  • the light intensity signal is a signal that directly or indirectly indicates the light intensity (for example, average light intensity) of scattered light received by the light receiving element 12.
  • the light intensity signal is often a signal component having a frequency of 1 kHz or less, for example. Therefore, it is preferable that the LPF 141 has a cutoff frequency capable of cutting a signal component having a frequency higher than the light intensity signal (for example, 1 kHz or more) while transmitting at least the light intensity signal.
  • the A / D converter 142 performs A / D conversion processing (that is, quantization processing) on the light intensity signal output from the LPF 141. As a result, the A / D converter 142 calculates the sample value (that is, the quantized light intensity signal) of the light intensity signal included in the voltage signal corresponding to the scattered light received by the light receiving element 12 as the arithmetic circuit 143. Output to.
  • a / D conversion processing that is, quantization processing
  • the arithmetic circuit 143 constitutes a specific example of “calculation means”, and the output of the A / D converter 142 (that is, the light intensity signal included in the voltage signal corresponding to the scattered light received by the light receiving element 12).
  • the blood flow concentration N is calculated based on the sample value.
  • the blood flow concentration N calculated by the calculator 143 may be output to the outside of the concentration calculation device 1 (or to a processing block (not shown) provided in the concentration calculation device 1) at an appropriate timing. .
  • FIG. 2 is a flowchart showing an operation flow of the concentration calculation apparatus 1 of the first embodiment.
  • the laser element 11 irradiates the tube 100 with the laser beam LB (step S11). At this time, it is preferable that the laser element 11 irradiates the laser beam LB with respect to the flow channel 101 in the tube 100 (that is, the flow channel 101 in which blood flows).
  • FIG. 3 is a cross-sectional view illustrating a specific mode of irradiation of the tube 100 with the laser beam LB.
  • the laser element 11 has a far field pattern FFP (that is, an elliptical pattern) of the laser light LB in the tube 100 in the far field pattern FFP.
  • the laser beam LB is irradiated so as to be formed in a region corresponding to the flow path 101 in the projection surface.
  • the laser element 11 has a laser beam LB so that the far field pattern FFP of the laser beam LB in the tube 100 is not formed in a region corresponding to the side wall 102 in the projection surface of the far field pattern FFP. Irradiate.
  • the laser element 11 is formed so that all of the far field pattern FFP of the laser light LB in the tube 100 is formed in a region corresponding to the flow path 101 in the projection surface of the far field pattern FFP. Irradiate with laser beam LB.
  • the laser element 11 is disposed in the flow paths 101 distributed in the left-right direction and the front-rear direction along the optical axis of the laser light LB (that is, the flow paths 101 distributed on the optical axis or the optical path of the laser light LB).
  • the laser beam LB is irradiated so that the laser beam LB is irradiated.
  • the laser element 11 irradiates the side wall 102 distributed in the left-right direction along the optical axis of the laser beam LB (that is, the side wall 102 not distributed on the optical axis or optical path of the laser beam LB) with the laser beam LB.
  • the laser beam LB is irradiated so as not to occur.
  • the laser beam LB is distributed in the front-rear direction along the optical axis of the laser beam LB (that is, the optical axis or the laser beam LB).
  • the side wall 102) distributed on the optical path may be irradiated.
  • the optical axis of the laser beam LB is an axis along the direction from the back side of the paper to the front side of the paper or the direction from the front side of the paper to the back side of the paper. .
  • the laser element 11 may irradiate the laser beam LB so that the long axis of the far field pattern FFP intersects the central axis of the flow path.
  • the laser element 11 may irradiate the laser beam LB so that the long axis of the far field pattern FFP is parallel to the central axis of the flow path. More preferably, as shown in FIG. 3B, the laser element 11 may irradiate the laser beam LB so that the long axis of the far field pattern FFP coincides with the central axis of the flow path.
  • the laser element 11 may irradiate the laser beam LB so that the long axis of the far field pattern FFP is orthogonal to the central axis of the flow path.
  • the laser element 11 is set so that the laser beam LB is irradiated in the above-described manner when the tube 100 is attached to the concentration calculation apparatus 1.
  • the attachment angle of the laser element 11 according to the outer diameter of the attached tube 100, the inner diameter of the tube 100, the refractive index of the side wall 102, and the like.
  • the distance (for example, optical distance) between the laser element 11 and the light receiving element 12 is set to an appropriate distance according to the maximum value of the outer diameter of the tube 100 attached to the concentration detection device 1. Is preferred.
  • the light receiving element 12 receives the scattered light of the laser light LB from the tube 100 (step S12). More specifically, the light receiving element 12 includes scattered light scattered by blood flowing in the tube 100 (particularly, blood cells that are moving scatterers contained in the blood) and stationary tissue ( For example, the scattered light scattered by the tube 100 itself is received. As the scattered light, forward scattered light corresponding to the transmitted light of the laser light LB irradiated to the tube 100 may be used, or back scattered light corresponding to the reflected light of the laser light LB irradiated to the tube 100. May be used.
  • the light receiving element 12 generates a light receiving signal obtained by converting the received scattered light into an electric signal (step S12). Thereafter, the light receiving element 12 outputs the generated light reception signal to the amplifier 13.
  • the received light signal includes a signal component corresponding to the light intensity of the scattered light (that is, the above-described light intensity signal and a relatively low-frequency signal component).
  • the amplifier 13 converts the received light signal output from the light receiving element 12 (that is, the received light signal corresponding to the scattered light received by the light receiving element 12) into a voltage signal and amplifies it (step S13). Thereafter, the amplifier 13 outputs the amplified light reception signal to the arithmetic circuit 14. More specifically, the amplifier 13 outputs the amplified light reception signal to the LPF 141.
  • the LPF 141 cuts signal components in frequency bands other than the low-frequency signal component among the signal components included in the light reception signal output from the amplifier 13. As a result, the LPF 141 acquires a light intensity signal corresponding to the low-frequency signal component among the signal components included in the output of the amplifier 13 (step S14). Thereafter, the LPF 141 outputs the acquired light intensity signal to the A / D converter 142.
  • the A / D converter 142 performs A / D conversion processing (that is, quantization processing) on the light intensity signal output from the LPF 141 (step S15). Specifically, for example, when the sampling period of the A / D converter 142 is Ta1, the A / D converter 142 calculates a sample value of the light intensity signal (that is, a quantized light intensity signal) for each period Ta1. Output. Thereafter, the A / D converter 142 outputs a sample value (that is, a quantized light intensity signal) of the light intensity signal corresponding to the light intensity of the scattered light received by the light receiving element 12 to the calculator 143.
  • a / D conversion processing that is, quantization processing
  • the calculator 143 calculates the blood flow concentration N based on the output of the A / D converter 142 (that is, the sample value of the light intensity signal corresponding to the light intensity of the scattered light received by the light receiving element 12) (step S1). S16).
  • FIG. 4 shows the correlation between the light intensity signal and the blood flow concentration N when the light receiving element 12 receives the forward scattered light of the laser light LB, and the case where the light receiving element 12 receives the back scattered light of the laser light LB. It is a graph which shows the correlation between the light intensity signal and blood flow concentration N.
  • the 4A shows a correlation between the light intensity signal (specifically, the signal level of the light intensity signal) and the blood flow concentration N when the light receiving element 12 receives the forward scattered light of the laser light LB. Is shown.
  • the light intensity signal specifically, the signal level of the light intensity signal
  • the blood flow concentration N the blood flow concentration of the light intensity signal.
  • the signal level of the light intensity signal increases as the blood flow concentration N decreases. In other words, the more blood cells that are scatterers that hinder the transmission of the laser beam LB, the smaller the light intensity signal.
  • the computing unit 143 refers to the correlation information shown in FIG. 4A held in advance inside or outside the computing unit 143.
  • the blood flow concentration N corresponding to the light intensity signal output from the A / D converter 142 is calculated.
  • the calculator 143 calculates a blood flow concentration N of “NH1”.
  • the calculator 143 determines the blood flow concentration N as “NL1 (where NL1 ⁇ NH1)”. Is calculated.
  • FIG. 4B shows the relationship between the light intensity signal (specifically, the signal level of the light intensity signal) and the blood flow concentration N when the light receiving element 12 receives the backscattered light of the laser light LB.
  • the correlation is shown.
  • the signal level of the light intensity signal increases as the blood flow concentration N increases.
  • the signal level of the light intensity signal becomes smaller as the blood flow concentration N is lower. That is, the more the blood cells, which are scatterers that reflect the laser beam LB, are contained in the blood, the greater the light intensity signal.
  • the computing unit 143 refers to the correlation information shown in FIG. 4B held in advance inside or outside the computing unit 143.
  • the blood flow concentration N corresponding to the light intensity signal output from the A / D converter 142 is calculated.
  • the calculator 143 calculates a blood flow concentration N of “NL2”.
  • the calculator 143 determines the blood flow concentration N as “NH2 (where NL2 ⁇ NH2)”. Is calculated.
  • the calculator 143 is not limited to the graph indicating the correlation between the light intensity signal and the blood flow concentration N, and any information indicating the correlation between the light intensity signal and the blood flow concentration N (for example, The blood flow concentration N according to the intensity of the optical signal output from the A / D converter 142 may be calculated by referring to a mathematical formula, a table, a map, or the like.
  • the computing unit 143 performs the blood flow concentration N based on the correlation information indicating the correlation between the light intensity signal and the blood flow concentration N shown in FIGS. 4 (a) and 4 (b). Is calculated. Therefore, the “blood flow concentration N” in the first embodiment is substantially synonymous with the concentration of blood cells contained in blood (that is, blood cells as scatterers). However, as the blood flow concentration N, other concentrations (for example, concentrations of substances other than blood cells contained in blood, etc.) may be used.
  • FIG. 5 is a cross-sectional view showing a specific mode of irradiation of the laser beam LB onto the tube 100 in the concentration calculation apparatus of the comparative example.
  • FIG. 6 is a graph showing a light reception signal acquired by the concentration calculation device 1 of the first embodiment and a light reception signal acquired by the concentration calculation device of the comparative example.
  • FIG. 7 shows normalization of a signal (standardized light reception signal) obtained by normalizing the light reception signal acquired by the concentration calculation device 1 of the first embodiment and a light reception signal acquired by the concentration calculation device of the comparative example.
  • FIG. 8 shows the correlation between the signal (normalized light intensity signal) obtained by normalizing the light intensity signal acquired by the concentration calculation apparatus 1 of the first embodiment and the blood flow concentration N and the comparative example. It is a graph which shows the correlation between the signal (normalized light intensity signal) obtained by normalizing the light intensity signal which a density
  • the far field pattern FFP (that is, the elliptical pattern) of the laser beam LB in the tube 100 is the far field.
  • the laser beam LB is irradiated so as to be formed in a region corresponding to the flow path 101 in the projection surface of the pattern FFP.
  • the far field pattern FFP of the laser light LB in the tube 100 is formed also in a region corresponding to the side wall 102 in the projection surface of the far field pattern FFP. Then, the laser beam LB is irradiated.
  • the laser element 11 transmits the laser light LB to the flow paths 101 distributed in the front-rear direction along the optical axis of the laser light LB (that is, the flow paths 101 distributed on the optical axis or the optical path of the laser light LB). Is irradiated with the laser beam LB.
  • the laser beam LB is also applied to the side wall 102 distributed in the left-right direction along the optical axis of the laser beam LB (that is, the side wall 102 not distributed on the optical axis or optical path of the laser beam LB).
  • the laser beam LB is irradiated so as to be irradiated.
  • the optical axis of the laser beam LB is the direction from the back side to the front side of the paper or the paper surface, as in FIGS. 3 (a) to 3 (c). It is an axis along the direction from the near side to the back side of the drawing.
  • FIG. 6A shows the change in blood flow concentration N.
  • the blood flow concentration N changes from a relatively low concentration to a relatively high concentration at the concentration change point.
  • FIG. 6B shows a case where the laser light LB is irradiated to the blood whose blood flow concentration N changes in the mode shown in FIG. 6A, and the light receiving element 12 mainly receives forward scattered light.
  • An example of the received light signal obtained when the light receiving point is arranged opposite to the emission point of the laser element 11 via the tube 100 is shown.
  • the signal intensity of the received light signal acquired when the blood flow concentration is relatively low is higher than the signal intensity of the received light signal acquired when the blood flow concentration is relatively high. growing.
  • the light reception signal acquired by the concentration calculation device of the comparative example includes only a signal component corresponding to scattered light (here, forward scattered light corresponding to transmitted light) scattered by a scatterer such as a blood cell in blood.
  • a signal component that is, a DC offset component
  • the light reception signal acquired by the concentration calculation apparatus 1 according to the first embodiment corresponds to scattered light (here, forward scattered light corresponding to transmitted light) scattered by a scatterer such as a blood cell in blood.
  • a signal component that is, a DC offset component
  • the signal intensity of the received light signal acquired by the density calculation device of the comparative example is larger than the signal strength of the reception signal acquired by the density calculation device 1 of the first embodiment.
  • the concentration calculation apparatus 1 of the first embodiment calculates the blood flow concentration N by monitoring the change in the signal intensity of the received light signal (that is, the light intensity signal). be able to.
  • the concentration calculation apparatus of the comparative example can also calculate the blood flow concentration N by monitoring the change in the signal intensity of the received light signal (that is, the light intensity signal).
  • the concentration calculation device 1 of the first embodiment is very useful in practice that the calculation resolution of the blood flow concentration N can be improved as compared with the concentration calculation device of the comparative example. Has an effect.
  • the calculation resolution of the blood flow concentration N will be described.
  • FIG. 7 shows a signal (standardized light reception signal) obtained by normalizing the light reception signal shown in FIG. 6B with the light reception signal acquired by the concentration calculation device of the comparative example at time t1.
  • the amount of change in the signal intensity of the standardized light reception signal acquired by the concentration calculation device 1 of the first embodiment is the concentration calculation of the comparative example. It becomes larger than the change amount of the signal intensity of the standardized light reception signal acquired by the apparatus.
  • the concentration calculation device 1 can also calculate a relatively small change in blood flow concentration N. This is because, in the concentration calculation device of the comparative example, the signal component (DC offset component) caused by stray light is superimposed on the received light signal, so that the amplifier 13 is compared with the concentration calculation device 1 of the first embodiment. When the gain is increased, the amplifier 13 is likely to be saturated.
  • the concentration calculation apparatus 1 of the first embodiment since the signal component (DC offset component) caused by stray light is hardly superimposed on the light reception signal, the amplifier 13 is compared with the concentration calculation apparatus of the comparative example. Even if the gain is increased, the amplifier 13 is not easily saturated. That is, the concentration calculation apparatus 1 of the first embodiment can further increase the gain of the amplifier 13 as compared with the concentration calculation apparatus of the comparative example. Therefore, the concentration calculation apparatus 1 of the first embodiment can easily calculate a change in signal strength of the received signal (particularly a relatively small change) as compared with the concentration calculation apparatus of the comparative example. For this reason, the calculation resolution of the blood flow concentration N realized by the concentration calculation device 1 of the first embodiment is higher than the calculation resolution of the blood flow concentration N realized by the concentration calculation device of the comparative example.
  • the improvement in the calculation resolution is also apparent from FIG. 8 showing the correlation between the signal obtained by normalizing the light intensity signal (standardized light intensity signal) and the blood flow concentration N.
  • the change amount of the normalized light intensity signal acquired by the concentration calculation device 1 of the first embodiment with respect to the blood flow concentration N that changes by the same change amount is determined by the concentration calculation device of the comparative example. It becomes larger than the change amount of the signal intensity of the standardized light intensity signal to be acquired.
  • the concentration calculation apparatus 1 of the first embodiment the region portion in which the far field pattern FFP of the laser light LB in the tube 100 corresponds to the side wall 102 of the projection surface of the far field pattern FFP.
  • the laser beam LB is irradiated so as not to be formed.
  • the concentration calculation device 1 of the first embodiment can relatively improve the calculation resolution of the blood flow concentration N as compared with the concentration calculation device of the comparative example.
  • the concentration calculation apparatus 1 includes an optical system such as a collimator lens between the laser element 11 and the tube 100. Not necessary. Therefore, the cost of the concentration calculation device 1 is reduced. In addition, when the concentration calculation apparatus 1 does not include an optical system, it is not necessary to adjust the focus of the optical system when the tube 100 is replaced. It becomes easy. On the other hand, even when the concentration calculation device 1 calculates the blood flow concentration N by forming the far field pattern FFP, as described above, the side wall distributed in the left-right direction along the optical axis of the laser beam LB.
  • the concentration calculation apparatus 1 of the first embodiment is very useful in practice in that it can suppress a significant decrease).
  • FIG. 9 is a block diagram showing the configuration of the concentration calculation apparatus 2 of the second embodiment.
  • the concentration calculation apparatus 2 of the second embodiment includes a laser element 11, a light receiving element 12, and an amplifier 13, as in the concentration calculation apparatus 1 of the first embodiment.
  • the concentration calculation device 2 of the second embodiment is different from the concentration calculation device 1 of the first embodiment in that it further includes a light receiving element 22 and an amplifier 23.
  • the concentration calculation device 2 of the second embodiment further includes an arithmetic circuit 24.
  • the arithmetic circuit 24 of the second embodiment is different from the arithmetic circuit 14 of the first embodiment in that it further includes an HPF 244, an A / D converter 245, and an arithmetic unit 246.
  • concentration calculation device 2 of the second embodiment may be the same as other components included in the concentration calculation device 1 of the first embodiment.
  • the light receiving element 22 receives the scattered light of the laser beam LB irradiated on the tube 100.
  • the light receiving element 22 generates a received light signal obtained by converting the received scattered light into an electrical signal.
  • the amplifier 23 amplifies the light receiving signal, which is a current signal output from the light receiving element 22, after converting it into a voltage signal.
  • the HPF 244 cuts signal components in frequency bands other than the high-frequency signal component among the signal components included in the output of the amplifier 23 (that is, the received light signal corresponding to the scattered light received by the light receiving element 22). As a result, the HPF 244 outputs to the A / D converter 245 a beat signal corresponding to the high frequency signal component of the signal components included in the output of the amplifier 23.
  • the beat signal extracted by the HPF 244 is, for example, an optical beat signal generated by mutual interference between scattered light scattered by blood cells that are moving scatterers and scattered light scattered by a stationary tissue.
  • the beat signal is often a signal component having a frequency of 1 kHz or more, for example. Therefore, it is preferable that the HPF 244 has a cut-off frequency capable of cutting a signal component having a frequency (for example, 1 kHz or less) lower than that of the beat signal while transmitting at least the beat signal.
  • a BPF Band capable of cutting both a signal component having a frequency higher than the frequency of the beat signal and a signal component having a frequency lower than the frequency of the beat signal while transmitting at least the beat signal. Pass Filter may be used.
  • the A / D converter 245 performs A / D conversion processing (that is, quantization processing) on the beat signal output from the HPF 244. As a result, the A / D converter 245 outputs the beat signal sample value (that is, the quantized beat signal) included in the voltage signal corresponding to the scattered light received by the light receiving element 22 to the arithmetic circuit 246. To do.
  • a / D conversion processing that is, quantization processing
  • the arithmetic circuit 246 performs FFT (Fast Transform) on the output of the A / D converter 245 (that is, the sample value of the beat signal included in the voltage signal corresponding to the scattered light received by the light receiving element 22). Perform the frequency analysis used. As a result, the arithmetic circuit 246 calculates the blood flow rate Q.
  • FFT Fast Transform
  • the blood flow volume Q calculated by the calculator 246 may be output to the outside of the concentration calculation device 2 (or to a processing block (not shown) included in the concentration calculation device 2) at an appropriate timing.
  • FIG. 10 is a flowchart showing the operation flow of the concentration calculation apparatus 2 of the second embodiment.
  • the laser element 11 irradiates the tube 100 with the laser beam LB (step S11).
  • the specific mode of irradiation with the laser beam LB in the second embodiment is the same as the specific mode of irradiation with the laser beam LB in the first embodiment (see FIG. 3).
  • the operations from step S12 to step S16 are performed as in the first embodiment.
  • the light receiving element 12 is a light receiving signal obtained by converting the received scattered light into an electric signal (that is, a signal component corresponding to the light intensity of the scattered light (that is, the light intensity signal described above).
  • a light receiving signal including a relatively low frequency signal component is generated (step S12).
  • the amplifier 13 converts the received light signal output from the light receiving element 12 (that is, the received light signal corresponding to the scattered light received by the light receiving element 12) into a voltage signal and then amplifies it (step S13).
  • the LPF 141 acquires a light intensity signal corresponding to a low-frequency signal component among signal components included in the output of the amplifier 13 (step S14). Thereafter, the A / D converter 142 performs A / D conversion processing (that is, quantization processing) on the light intensity signal output from the LPF 141 (step S15). Thereafter, the calculator 143 calculates the blood flow concentration N based on the output of the A / D converter 142 (that is, the sample value of the light intensity signal corresponding to the light intensity of the scattered light received by the light receiving element 12) (step S1). S16).
  • the light receiving element 22 obtains the received scattered light by converting the received scattered light into an electrical signal following or in parallel with the operation of calculating the blood flow concentration N in steps S12 to S16.
  • the received light signal is generated (step S22). Thereafter, the light receiving element 22 outputs the generated light reception signal to the amplifier 23.
  • the light reception signal received by the light receiving element 22 corresponds to beat signal light generated by mutual interference between scattered light scattered by blood cells that are moving scatterers and scattered light scattered by a stationary tissue.
  • the signal component (that is, the above-described beat signal and a relatively high frequency signal component) is included.
  • the frequency of the scattered light scattered by the blood cell that is the moving scatterer is compared with the frequency of the scattered light scattered by the stationary tissue, and the laser Doppler action corresponding to the blood flow velocity v. Has changed.
  • the signal component corresponding to the beat signal light includes a signal component indicating a change in frequency according to the blood flow velocity v.
  • the amplifier 23 converts the received light signal output from the light receiving element 22 (that is, the received light signal corresponding to the scattered light received by the light receiving element 22) into a voltage signal and then amplifies it (step S23). Thereafter, the amplifier 23 outputs the amplified light reception signal to the arithmetic circuit 24. More specifically, the amplifier 23 outputs the amplified light reception signal to the HPF 244.
  • the HPF 244 cuts signal components in frequency bands other than the high-frequency signal component among the signal components included in the light reception signal output from the amplifier 23. As a result, the HPF 244 acquires a beat signal corresponding to the high frequency signal component among the signal components included in the output of the amplifier 23 (step S24). Thereafter, the HPF 244 outputs the acquired beat signal to the A / D converter 245.
  • the A / D converter 245 performs A / D conversion processing (that is, quantization processing) on the beat signal output from the HPF 244 (step S25). Specifically, for example, when the sampling period of the A / D converter 245 is Ta2, the A / D converter 245 outputs a beat signal sample value (that is, a quantized beat signal) for each period Ta2. . Thereafter, the A / D converter 245 outputs a beat signal sample value (that is, a quantized beat signal), which is an interference component of scattered light received by the light receiving element 22, to the computing unit 246.
  • a / D conversion processing that is, quantization processing
  • the calculator 246 calculates the blood flow rate Q based on the output of the A / D converter 245 (that is, the sample value of the beat signal that is the interference component of the scattered light received by the light receiving element 22) (step S26). Specifically, for example, the arithmetic unit 246 performs FFT on the sample value of the beat signal. The computing unit 246 calculates the blood flow rate Q using a first moment that is a multiplication result of the power spectrum and the frequency vector obtained by performing the FFT. Since a known method (for example, a method disclosed in Japanese Patent No. 3313841) may be used as a method for calculating the blood flow rate Q by frequency analysis using FFT, detailed description thereof is omitted.
  • Such a concentration detection apparatus 2 of the second embodiment can preferably enjoy the same effects as the various effects that the concentration detection apparatus 1 of the first embodiment can enjoy.
  • the concentration detection apparatus 2 according to the second embodiment can calculate not only the blood flow concentration N but also the blood flow Q by irradiating the tube 100 with the laser light LB.
  • the concentration detection device 2 calculates the blood flow Q (specifically, the blood flow Q using the laser Doppler flowmetry method).
  • the blood flow Q specifically, the blood flow Q using the laser Doppler flowmetry method.
  • the laser beam LB is irradiated in the above-described manner (see FIG. 3)
  • the blood flow concentration N and the blood flow rate Q are both calculated by irradiating the tube 100 with the laser beam LB.
  • a decrease in the calculation resolution of the blood flow concentration N is suppressed.
  • FIG. 11 is a block diagram showing the configuration of the concentration calculation apparatus 3 of the third embodiment.
  • the same configuration and operation as those of the concentration calculation apparatus 1 of the first embodiment are denoted by the same reference numerals and step numbers, and detailed description thereof is omitted.
  • the concentration calculation device 3 of the third embodiment is different from the concentration calculation device 1 of the first embodiment in that it further includes an APC (Automatic Power Control) circuit 31. Yes.
  • Other components included in the concentration calculation device 3 of the third embodiment may be the same as other components included in the concentration calculation device 1 of the first embodiment.
  • the APC circuit 31 includes a back monitor 311, an amplifier 312, a subtractor 313, and a controller 314.
  • the back monitor 311 is a laser beam LB emitted from the laser element 11 (particularly, the emission end face of the laser element 11).
  • the laser beam LB) leaking from the end surface on the opposite side of the laser beam is received.
  • the back monitor 311 generates a light reception signal obtained by converting the received laser light LB into an electrical signal.
  • the amplifier 312 amplifies the light reception signal, which is a current signal output from the back monitor 311, after converting it into a voltage signal.
  • the subtractor 313 subtracts the voltage signal output from the amplifier 312 from a predetermined target signal (specifically, a signal corresponding to the target power of the laser beam LB emitted from the laser element 11). That is, the subtracter 313 calculates an error from the target power of the power of the laser beam LB currently emitted from the laser element 11. The subtractor 313 outputs an error signal indicating the error to the controller 314.
  • a predetermined target signal specifically, a signal corresponding to the target power of the laser beam LB emitted from the laser element 11.
  • the controller 314 performs phase compensation for executing stable negative feedback on the error signal output from the subtractor 313. Thereafter, the controller 314 controls the laser element 11 based on the error signal subjected to phase compensation. As a result, the laser element 11 emits the laser beam LB whose power is changed by an amount corresponding to the error signal subjected to phase compensation.
  • Such a concentration calculation device 3 of the third embodiment can preferably enjoy the same effects as the various effects that the concentration calculation device 1 of the first embodiment can enjoy.
  • the APC circuit 31 can cause the power of the laser beam LB emitted from the laser element 11 to follow the target power. Therefore, the laser element 11 can irradiate the laser beam LB stably. As a result, the concentration calculation device 3 can calculate the blood flow concentration N more suitably (in other words, with higher accuracy) by using the stable laser beam LB.
  • the concentration calculation device 3 may include a front monitor that receives the laser light LB emitted from the laser element 11 via a beam splitter in addition to or instead of the back monitor 311.
  • the present invention can be appropriately changed without departing from the gist or idea of the invention that can be read from the claims and the entire specification, and a concentration calculation apparatus and method involving such a change are also applicable to the technology of the present invention. Included in thought.
  • Concentration calculator 11 Laser element 12, 22 Light receiving element 13, 23 Amplifier 141 LPF 244 HPF 142, 245 A / D converter 143, 246 arithmetic unit 311 back monitor 312 amplifier 313 subtractor 314 controller

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Abstract

A density calculation device (1) is provided with the following: an emission means (11) for emitting laser light (LB) to a conduit (100) in which a liquid flows in a flow path (101) that is partitioned by lateral walls (102); a light receiving means (12) for acquiring a light reception signal by receiving the laser light emitted into the conduit; and a calculation means (143) for calculating the density (N) of the liquid on the basis of the signal strength of the light reception signal. The emission means emits laser light so that a far field pattern (FFP) of the laser light is formed at partial regions, corresponding to the flow path, of the projection surface which is the laser light projection surface in the conduit and that follows the central axis of the flow path, while a far field pattern is not formed at partial regions, corresponding to the lateral walls, of the projection surface.

Description

濃度算出装置及び方法Concentration calculation apparatus and method
　本発明は、例えば血流等の流体の濃度を算出する濃度算出装置及び方法の技術分野に関する。 The present invention relates to a technical field of a concentration calculation apparatus and method for calculating a concentration of a fluid such as a blood flow.
　この種の濃度算出装置として、例えば、煙粒子を包含する吸入空気に照射したレーザ光の散乱光から、煙濃度を算出する濃度算出装置が存在する（例えば、特許文献１参照）。特許文献１に開示された濃度算出装置は、結像レンズ等の光学系を用いてレーザ光のニアフィールドパターンを、吸入空気が通過する結像位置に結像させることで、煙濃度を算出している。 As this type of concentration calculation device, for example, there is a concentration calculation device that calculates the smoke concentration from the scattered light of laser light irradiated to the intake air containing smoke particles (see, for example, Patent Document 1). The density calculation device disclosed in Patent Document 1 calculates a smoke density by forming a near-field pattern of laser light at an imaging position through which intake air passes using an optical system such as an imaging lens. ing.
　その他、この種の濃度算出装置として、例えば、免疫クロマトグラフィー試験片に照射したビームの透過光又は反射光から、試料濃度を測定する濃度算出装置が存在する（例えば、特許文献２参照）。 In addition, as this type of concentration calculation device, for example, there is a concentration calculation device that measures a sample concentration from transmitted light or reflected light of a beam irradiated on an immunochromatographic test piece (see, for example, Patent Document 2).
特許第３７８３９９１号公報Japanese Patent No. 3783991 特許第４７９７２３３号公報Japanese Patent No. 4797233
　一方で、濃度算出装置は、管路内を流れている流体の濃度を算出する場合がある。具体的には、例えば、濃度算出装置は、透明状のチューブ内を流れている血流の濃度を算出する場合がある。この場合、管路に対するレーザ光の照射態様によっては、濃度の算出分解能（言い換えれば、算出精度）が低下してしまうという技術的問題点が生ずる。このような技術的問題点は、レーザ光が管路の側壁（つまり、流体が実際に流れる空隙である流路を取り囲む側壁）に照射されている場合に特に顕著に起こり得る。 On the other hand, the concentration calculation device may calculate the concentration of the fluid flowing in the pipeline. Specifically, for example, the concentration calculation device may calculate the concentration of blood flow flowing in a transparent tube. In this case, there is a technical problem in that the calculation resolution of the concentration (in other words, the calculation accuracy) decreases depending on the mode of irradiation of the laser beam to the pipe. Such a technical problem can be particularly noticeable when the laser beam is applied to the side wall of the pipe line (that is, the side wall surrounding the flow path, which is a gap through which the fluid actually flows).
　本発明は、例えば上記問題点に鑑みてなされたものであり、流体の濃度の算出分解能を向上させることが可能な濃度算出装置及び方法を提供することを課題とする。 The present invention has been made in view of the above-mentioned problems, for example, and an object of the present invention is to provide a concentration calculation apparatus and method capable of improving the calculation resolution of the fluid concentration.
　上記課題を解決するための濃度算出装置は、側壁で仕切られた流路に流体が流れている管路に対してレーザ光を照射する照射手段と、前記管路に照射された前記レーザ光を受光することで受光信号を取得する受光手段と、前記受光信号の信号強度に基づいて、前記流体の濃度を算出する算出手段とを備えており、前記照射手段は、(i)前記管路内での前記レーザ光の投影面であって且つ前記流路の中心軸に沿った投影面のうち前記流路に相当する領域部分に前記レーザ光のファーフィールドパターンが形成される一方で、(ii)前記投影面のうち前記側壁に相当する領域部分に前記ファーフィールドパターンが形成されないように、前記レーザ光を照射する。 A concentration calculation apparatus for solving the above-described problem includes an irradiation unit that irradiates laser light to a pipe line in which a fluid flows in a flow path partitioned by a side wall, and the laser light emitted to the pipe line. A light receiving unit that obtains a light reception signal by receiving light; and a calculation unit that calculates the concentration of the fluid based on the signal intensity of the light reception signal. A far field pattern of the laser light is formed in a region corresponding to the flow path in the projection plane of the laser light at and along the central axis of the flow path. ) Irradiating the laser beam so that the far field pattern is not formed in a region corresponding to the side wall of the projection surface.
　上記課題を解決するための濃度算出方法は、側壁で仕切られた流路に流体が流れている管路に対してレーザ光を照射する照射工程と、前記管路に照射された前記レーザ光を受光することで受光信号を取得する受光工程と、前記受光信号の信号強度に基づいて、前記流体の濃度を算出する算出工程とを備えており、前記照射工程では、(i)前記管路内での前記レーザ光の投影面であって且つ前記流路の中心軸に沿った投影面のうち前記流路に相当する領域部分に前記レーザ光のファーフィールドパターンが形成される一方で、(ii)前記投影面のうち前記側壁に相当する領域部分に前記ファーフィールドパターンが形成されないように、前記レーザ光が形成される。 The concentration calculation method for solving the above-described problems includes an irradiation step of irradiating laser light to a pipe line in which a fluid flows in a flow path partitioned by side walls, and the laser light irradiated to the pipe line. A light receiving step for obtaining a light reception signal by receiving light, and a calculation step for calculating the concentration of the fluid based on a signal intensity of the light reception signal. In the irradiation step, (i) in the pipe line A far field pattern of the laser light is formed in a region corresponding to the flow path in the projection plane of the laser light at and along the central axis of the flow path. The laser beam is formed so that the far field pattern is not formed in a region corresponding to the side wall of the projection surface.
第１実施例の濃度算出装置の構成を示すブロック図である。It is a block diagram which shows the structure of the density | concentration calculation apparatus of 1st Example. 第１実施例の濃度算出装置の動作の流れを示すフローチャートである。It is a flowchart which shows the flow of operation | movement of the density | concentration calculation apparatus of 1st Example. チューブに対するレーザ光の照射の具体的態様を示す断面図である。It is sectional drawing which shows the specific aspect of irradiation of the laser beam with respect to a tube. 受光素子がレーザ光の前方散乱光を受光する場合の光強度信号と血流濃度との間の相関関係及び受光素子がレーザ光の後方散乱光を受光する場合の光強度信号と血流濃度との間の相関関係を示すグラフである。The correlation between the light intensity signal and the blood flow concentration when the light receiving element receives the forward scattered light of the laser light, and the light intensity signal and the blood flow concentration when the light receiving element receives the back scattered light of the laser light. It is a graph which shows the correlation between. 比較例の濃度算出装置におけるチューブに対するレーザ光の照射の具体的態様を示す断面図である。It is sectional drawing which shows the specific aspect of irradiation of the laser beam with respect to the tube in the density | concentration calculation apparatus of a comparative example. 第１実施例の濃度算出装置が取得する受光信号及び比較例の濃度算出装置が取得する受光信号を示すグラフである。It is a graph which shows the light reception signal which the density | concentration calculation apparatus of 1st Example acquires, and the light reception signal which the density | concentration calculation apparatus of a comparative example acquires. 第１実施例の濃度算出装置が取得する受光信号を規格化することで得られる信号（規格化受光信号）及び比較例の濃度算出装置が取得する受光信号を規格化することで得られる信号（規格化受光信号）を示すグラフである。A signal (standardized light reception signal) obtained by normalizing a light reception signal acquired by the concentration calculation apparatus of the first embodiment and a signal (standardized light reception signal acquired by the density calculation apparatus of the comparative example) ( It is a graph which shows a normalization light reception signal. 第１実施例の濃度算出装置が取得する光強度信号を規格化することで得られる信号（規格化光強度信号）と血流濃度との間の相関関係及び比較例の濃度算出装置が取得する光強度信号を規格化することで得られる信号（規格化光強度信号）と血流濃度との間の相関関係を示すグラフである。The correlation between the signal obtained by normalizing the light intensity signal acquired by the concentration calculation apparatus of the first embodiment (standardized light intensity signal) and the blood flow concentration and the concentration calculation apparatus of the comparative example acquire. It is a graph which shows the correlation between the signal (normalized light intensity signal) obtained by normalizing a light intensity signal, and blood flow concentration. 第２実施例の濃度算出装置の構成を示すブロック図である。It is a block diagram which shows the structure of the density | concentration calculation apparatus of 2nd Example. 第２実施例の濃度算出装置の動作の流れを示すフローチャートである。It is a flowchart which shows the flow of operation | movement of the density | concentration calculation apparatus of 2nd Example. 第３実施例の濃度算出装置の構成を示すブロック図である。It is a block diagram which shows the structure of the density | concentration calculation apparatus of 3rd Example.
　以下、発明を実施するための形態として、濃度算出装置及び方法の実施形態について順に説明する。 Hereinafter, embodiments of the concentration calculation apparatus and method will be described in order as modes for carrying out the invention.
　（濃度算出装置の実施形態）
　＜１＞
　本実施形態の濃度算出装置は、側壁で仕切られた流路に流体が流れている管路に対してレーザ光を照射する照射手段と、前記管路に照射された前記レーザ光を受光することで受光信号を取得する受光手段と、前記受光信号の信号強度に基づいて、前記流体の濃度を算出する算出手段とを備えており、前記照射手段は、(i)前記管路内での前記レーザ光の投影面であって且つ前記流路の中心軸に沿った投影面のうち前記流路に相当する領域部分に前記レーザ光のファーフィールドパターンが形成される一方で、(ii)前記投影面のうち前記側壁に相当する領域部分に前記ファーフィールドパターンが形成されないように、前記レーザ光を照射する。 (Embodiment of concentration calculation apparatus)
<1>
The concentration calculation apparatus according to the present embodiment receives an irradiation unit that irradiates laser light to a pipe line in which a fluid flows in a flow path partitioned by side walls, and receives the laser light emitted to the pipe line. A light receiving means for acquiring a light reception signal and a calculation means for calculating the concentration of the fluid based on the signal intensity of the light reception signal, and the irradiation means (i) While the far field pattern of the laser beam is formed in a region corresponding to the flow path in the projection plane of the laser light and along the central axis of the flow path, (ii) the projection The laser beam is irradiated so that the far field pattern is not formed on a portion of the surface corresponding to the side wall.
　本実施形態の濃度算出装置によれば、照射手段は、被測定対象である管路に対してレーザ光を照射する。管路は、流体が流れる空隙である流路と、当該流路を仕切る（言い換えれば、当該流路を規定する）側壁を備えている。尚、側壁は、典型的には、流路を取り囲むチューブ状の又は円柱状の側壁となる。レーザ光は、管路の内部を流れている流体に対して照射されることが好ましい。このため、管路は、透明状（但し、ある程度のレーザ光の透過を許容する半透明状を含む）であることが好ましい。尚、管路及び流体の一例として、透明状のチューブ及び血液があげられる。或いは、管路及び流体の他の一例として、血管及び血液があげられる。或いは、管路及び流体の他の一例として、光が透過可能な窓を有する管及び透明状のチューブ並びに当該管内又は当該チューブ内を流れる流体（例えば、インクや油や汚水や調味料等の光を散乱する散乱体、あるいは光を吸収する吸光体を少なくとも構成要素として含む流体）があげられる。 According to the concentration calculation apparatus of the present embodiment, the irradiating means irradiates the pipe that is the measurement target with laser light. The pipe line includes a channel that is a gap through which a fluid flows and a side wall that partitions the channel (in other words, defines the channel). The side wall is typically a tubular or columnar side wall surrounding the flow path. The laser light is preferably applied to the fluid flowing inside the pipe line. For this reason, it is preferable that the pipe line is transparent (including a translucent shape that allows a certain amount of laser light to pass through). In addition, a transparent tube and blood are mention | raise | lifted as an example of a pipe line and a fluid. Alternatively, other examples of the conduit and the fluid include blood vessels and blood. Alternatively, as another example of the conduit and the fluid, a tube having a light transmissive window, a transparent tube, and a fluid flowing in the tube or the tube (for example, light such as ink, oil, sewage, seasoning, etc. And a fluid containing at least a light absorber that absorbs light as a constituent element).
　受光手段は、照射手段によって管路に照射されたレーザ光を受光する。具体的には、例えば、受光手段は、管路及び管路内を流れる流体の少なくとも一方によって散乱されたレーザ光（いわゆる、散乱光）を受光する。このとき、受光手段は、管路を透過してきたレーザ光（いわゆる、透過光に相当する前方散乱光）を受光してもよいし、管路及び管路内を流れる流体の少なくとも一方によって反射されたレーザ光（いわゆる、反射光に相当する後方散乱光）を受光してもよい。その結果、受光手段からは、受光したレーザ光（特に、当該レーザ光の散乱光）に応じた受光信号が出力される。 The light receiving means receives the laser beam irradiated to the pipe line by the irradiation means. Specifically, for example, the light receiving means receives laser light (so-called scattered light) scattered by at least one of the pipe and the fluid flowing in the pipe. At this time, the light receiving means may receive the laser light transmitted through the pipe (so-called forward scattered light corresponding to the transmitted light) or reflected by at least one of the pipe and the fluid flowing in the pipe. Alternatively, laser light (so-called backscattered light corresponding to reflected light) may be received. As a result, a light receiving signal corresponding to the received laser light (particularly, scattered light of the laser light) is output from the light receiving means.
　算出手段は、受光信号の信号強度（例えば、平均信号強度又は受信信号に含まれるＤＣ成分の信号強度等）に基づいて、流体の濃度を算出する。例えば、受光手段が管路及び管路内を流れる流体の少なくとも一方によって透過してきたレーザ光（つまり、前方散乱光）を受光する場合には、流体の濃度が高ければ高いほど（つまり、レーザ光の透過を妨げる散乱体等が流体内に多く含まれていればいるほど）、受光信号の信号強度は小さくなる。或いは、例えば、受光手段が管路及び管路内を流れる流体の少なくとも一方によって反射されたレーザ光（つまり、後方散乱光）を受光する場合には、流体の濃度が高ければ高いほど（つまり、レーザ光を反射させる散乱体等が流体内に多く含まれていればいるほど）、受光信号の信号強度は大きくなる。算出手段は、このような受光信号の信号強度と濃度との間の関係を用いて、濃度を算出する。 The calculating means calculates the concentration of the fluid based on the signal intensity of the received light signal (for example, the average signal intensity or the signal intensity of the DC component included in the received signal). For example, when the light receiving means receives laser light (that is, forward scattered light) transmitted by at least one of the pipe and the fluid flowing in the pipe, the higher the concentration of the fluid (that is, the laser light) The more scatterers and the like that prevent the transmission of light, the more the fluid is contained in the fluid), the smaller the signal intensity of the received light signal. Alternatively, for example, when the light receiving means receives laser light (that is, backscattered light) reflected by at least one of the pipe and the fluid flowing in the pipe, the higher the concentration of the fluid (that is, The more scatterers etc. that reflect the laser light are contained in the fluid), the greater the signal intensity of the received light signal. The calculating means calculates the density using the relationship between the signal intensity and the density of the received light signal.
　尚、このような受光信号の信号強度と濃度との間の関係を用いて濃度が算出されているため、本実施形態における「流体の濃度」とは、流体内に含まれている散乱体の濃度に相当する。 Since the concentration is calculated using the relationship between the signal intensity and the concentration of such a light reception signal, the “fluid concentration” in this embodiment is the scatterer included in the fluid. Corresponds to concentration.
　本実施形態では特に、照射手段は、レーザ光の投影面上において以下の条件を満たすファーフィールドパターンが形成されるように、レーザ光を照射する。具体的には、本実施形態では、投影面のうち流路に相当する領域部分には、ファーフィールドパターンが形成される。その一方で、投影面のうち側壁に相当する領域部分には、ファーフィールドパターンが形成されない。つまり、投影面のうち流路に相当する領域部分に、ファーフィールドパターンの全体が形成される。言い換えれば、本実施形態では、レーザ光は、当該レーザ光の光軸に沿って左右方向に分布する側壁（つまり、レーザ光の光軸又は光路上に分布していない側壁）には照射されない。但し、レーザ光が管路の内部の流体に照射される以上、レーザ光は、当該レーザ光の光軸に沿って前後方向に分布する側壁（つまり、レーザ光の光軸又は光路上に分布する側壁）には照射されてもよい。 Particularly in the present embodiment, the irradiation means irradiates the laser beam so that a far field pattern satisfying the following conditions is formed on the projection surface of the laser beam. Specifically, in the present embodiment, a far field pattern is formed in a region corresponding to the flow path in the projection surface. On the other hand, the far field pattern is not formed in the region corresponding to the side wall of the projection surface. That is, the entire far field pattern is formed in the region corresponding to the flow path on the projection surface. In other words, in the present embodiment, the laser light is not irradiated on the side wall distributed in the left-right direction along the optical axis of the laser light (that is, the side wall not distributed on the optical axis of the laser light or the optical path). However, as long as the laser light is applied to the fluid inside the pipe, the laser light is distributed in the front-rear direction along the optical axis of the laser light (that is, distributed on the optical axis or the optical path of the laser light). The side wall) may be irradiated.
　尚、ここで言う「投影面」とは、レーザ光のファーフィールドパターンが形成される管路内の投影面を示す。このような「投影面」は、例えば、管路内でのレーザ光の投影面であって、且つ流路の中心軸に沿った（或いは、平行な）投影面である。言い換えれば、「投影面」は、例えば、管路内でのレーザ光の投影面であって、且つ流路の中心軸を通る投影面である。更に言い換えれば、「投影面」は、管路内でのレーザ光の投影面であって、レーザ光の光軸と交わる（或いは、直交する）投影面であって、且つ流路の中心軸に沿った（或いは、平行な）若しくは流路の中心軸を含む投影面である。尚、流路の中心軸に対して直交する光軸を有するレーザ光が管路に照射される場合は、投影面は、レーザ光の光軸に直交する管路の断面に相当する。 Incidentally, the “projection plane” referred to here indicates a projection plane in a pipe line on which a far field pattern of laser light is formed. Such a “projection plane” is, for example, a projection plane of laser light in a duct and a projection plane along (or parallel to) the central axis of the flow path. In other words, the “projection plane” is, for example, a projection plane of laser light in the pipe and a projection plane passing through the central axis of the flow path. Furthermore, in other words, the “projection plane” is a projection plane of the laser beam in the pipe, is a projection plane that intersects (or is orthogonal to) the optical axis of the laser beam, and is on the central axis of the flow path. A projection plane along (or parallel to) or including the central axis of the flow path. When laser light having an optical axis perpendicular to the central axis of the flow path is irradiated onto the pipe, the projection surface corresponds to a cross section of the pipe perpendicular to the optical axis of the laser light.
　このように、本実施形態では、レーザ光は、当該レーザ光の光軸に沿って左右方向に分布する側壁（つまり、レーザ光の光軸又は光路上に分布していない側壁）には照射されることはない。従って、レーザ光の光軸に沿って左右方向に分布する側壁にレーザ光が照射される比較例の濃度算出装置と比較して、側壁へのレーザ光の照射に起因した迷光の発生が抑制される。従って、比較例の濃度算出装置と比較して、迷光を受光することで取得される信号成分（例えば、ＤＣ成分のオフセットに相当する信号成分）に起因した受光信号の信号強度の意図せぬ増加が抑制される。このため、後に図面を用いて詳細に説明するように、比較例の濃度算出装置と比較して、信号強度に基づく濃度の算出分解能が向上する。 As described above, in this embodiment, the laser light is irradiated onto the side wall distributed in the left-right direction along the optical axis of the laser light (that is, the side wall not distributed on the optical axis of the laser light or the optical path). Never happen. Therefore, the generation of stray light due to the irradiation of the laser beam on the side wall is suppressed as compared with the concentration calculation device of the comparative example in which the side wall distributed in the horizontal direction along the optical axis of the laser beam is irradiated with the laser beam. The Therefore, compared with the concentration calculation device of the comparative example, an unintentional increase in the signal intensity of the received light signal due to the signal component acquired by receiving stray light (for example, the signal component corresponding to the offset of the DC component) Is suppressed. Therefore, as will be described in detail later with reference to the drawings, the density calculation resolution based on the signal intensity is improved as compared with the density calculation apparatus of the comparative example.
　＜２＞
　本実施形態の濃度算出装置の他の態様では、前記照射手段は、前記投影面上において、前記ファーフィールドパターンの長軸が前記流路の中心軸が延びる方向に沿って配置されるように、前記レーザ光を照射する。 <2>
In another aspect of the concentration calculation apparatus of the present embodiment, the irradiating means is arranged on the projection plane so that the long axis of the far field pattern extends along the direction in which the central axis of the flow path extends. Irradiate the laser beam.
　この態様によれば、照射手段は、投影面のうち側壁に相当する領域部分にファーフィールドパターンが形成されないように、レーザ光を照射しやすくなる。 According to this aspect, the irradiating means can easily irradiate the laser beam so that the far field pattern is not formed in the region corresponding to the side wall of the projection surface.
　＜３＞
　本実施形態の濃度算出装置の他の態様では、前記照射手段は、前記投影面上において、前記ファーフィールドパターンの長軸が前記流路の中心軸が延びる方向に対して平行に配置されるように、前記レーザ光を照射する。 <3>
In another aspect of the concentration calculation apparatus of this embodiment, the irradiation unit is arranged on the projection plane so that the long axis of the far field pattern is parallel to the direction in which the central axis of the flow path extends. Then, the laser beam is irradiated.
　この態様によれば、照射手段は、投影面のうち側壁に相当する領域部分にファーフィールドパターンが形成されないように、レーザ光を照射しやすくなる。 According to this aspect, the irradiating means can easily irradiate the laser beam so that the far field pattern is not formed in the region corresponding to the side wall of the projection surface.
　＜４＞
　本実施形態の濃度算出装置の他の態様では、前記照射手段は、前記投影面上において、前記ファーフィールドパターンの長軸の中心軸が前記流路の中心軸と一致するように、前記レーザ光を照射する。 <4>
In another aspect of the concentration calculation apparatus of the present embodiment, the irradiation unit includes the laser beam so that a central axis of a long axis of the far field pattern coincides with a central axis of the flow path on the projection plane. Irradiate.
　この態様によれば、照射手段は、投影面のうち側壁に相当する領域部分にファーフィールドパターンが形成されないように、レーザ光を照射しやすくなる。 According to this aspect, the irradiating means can easily irradiate the laser beam so that the far field pattern is not formed in the region corresponding to the side wall of the projection surface.
　＜５＞
　本実施形態の濃度算出装置の他の態様では、前記管路は、当該濃度算出装置に対して着脱可能な透明状の管路であり、前記流体は、前記被測定対象としての生体の外部を流れる前記生体の血流である。 <5>
In another aspect of the concentration calculation apparatus of the present embodiment, the conduit is a transparent conduit that can be attached to and detached from the concentration calculation apparatus, and the fluid passes outside the living body as the measurement target. It is the blood flow of the living body that flows.
　この態様によれば、照射手段は、透明状の管路内を流れる血流に対して、上述した態様でレーザ光を照射することができる。その結果、算出手段は、透明状の管路内を流れる血流の濃度を算出することができる。 According to this aspect, the irradiating means can irradiate the laser beam in the above-described manner with respect to the blood flow flowing in the transparent duct. As a result, the calculation means can calculate the concentration of the blood flow flowing in the transparent duct.
　＜６＞
　本実施形態の濃度算出装置の他の態様では、前記照射手段から照射される前記レーザ光の一部を受光することで前記レーザ光のパワーを所望レベルに保つパワー制御手段を更に備える。 <6>
In another aspect of the concentration calculation apparatus according to the present embodiment, the apparatus further includes power control means for keeping the power of the laser light at a desired level by receiving a part of the laser light emitted from the irradiation means.
　この態様によれば、パワー制御手段は、レーザ光のパワーが所望レベルとなるようにレーザ光のパワーを好適に制御することができる。 According to this aspect, the power control means can suitably control the power of the laser light so that the power of the laser light becomes a desired level.
　（濃度算出方法の実施形態）
　＜７＞
　本実施形態の濃度算出方法は、側壁で仕切られた流路に流体が流れている管路に対してレーザ光を照射する照射工程と、前記管路に照射された前記レーザ光を受光することで受光信号を取得する受光工程と、前記受光信号の信号強度に基づいて、前記流体の濃度を算出する算出工程とを備えており、前記照射工程では、(i)前記管路内での前記レーザ光の投影面であって且つ前記流路の中心軸に沿った投影面のうち前記流路に相当する領域部分に前記レーザ光のファーフィールドパターンが形成される一方で、(ii)前記投影面のうち前記側壁に相当する領域部分に前記ファーフィールドパターンが形成されないように、前記レーザ光が照射される。 (Embodiment of concentration calculation method)
<7>
The concentration calculation method of the present embodiment includes an irradiation step of irradiating laser light to a pipe line in which a fluid flows in a flow path partitioned by side walls, and receiving the laser light irradiated to the pipe line. A light receiving step for obtaining a light reception signal in step (b), and a calculation step for calculating the concentration of the fluid based on the signal intensity of the light reception signal.In the irradiation step, (i) the above in the pipeline While the far field pattern of the laser beam is formed in a region corresponding to the flow path in the projection plane of the laser light and along the central axis of the flow path, (ii) the projection The laser beam is irradiated so that the far field pattern is not formed on a portion of the surface corresponding to the side wall.
　本実施形態の濃度算出方法によれば、上述した本実施形態の濃度算出装置が享受する各種効果を好適に享受することができる。 According to the concentration calculation method of the present embodiment, various effects enjoyed by the above-described concentration calculation device of the present embodiment can be suitably enjoyed.
　尚、本実施形態の濃度算出装置が採用する各種態様に対応して、本実施形態の濃度算出方法も、各種態様を採用してもよい。 Incidentally, in response to various aspects adopted by the concentration calculation apparatus of the present embodiment, the concentration calculation method of the present embodiment may adopt various aspects.
　本実施形態のこのような作用及び他の利得は次に説明する実施例から明らかにされる。 Such an operation and other advantages of the present embodiment will be clarified from examples described below.
　以上説明したように、本実施形態の濃度算出装置は、照射手段と、受光手段と、算出手段とを備える。本実施形態の濃度算出方法は、照射工程と、受光工程と、算出工程とを備える。従って、本実施形態の濃度算出装置及び方法は、流体の濃度の算出分解能を向上させることができる。 As described above, the concentration calculation apparatus according to the present embodiment includes an irradiation unit, a light receiving unit, and a calculation unit. The concentration calculation method of this embodiment includes an irradiation process, a light receiving process, and a calculation process. Therefore, the concentration calculation apparatus and method of the present embodiment can improve the calculation resolution of the fluid concentration.
　以下、図面を参照しながら、濃度算出装置の実施例について説明する。尚、以下では、濃度算出装置を、人工透析装置の血流回路を構成するチューブ１００の中を流れる血液の濃度（つまり、血流濃度）を算出する濃度算出装置に適用した例について説明を進める。但し、濃度算出装置は、生体の血管内を流れる血液の濃度や、任意のチューブ内を流れる血液以外の任意の流体（例えば、インクや油や汚水や調味料等）の濃度を算出する任意の濃度算出装置に適用されてもよい。 Hereinafter, embodiments of the concentration calculation apparatus will be described with reference to the drawings. In the following description, an example in which the concentration calculation device is applied to a concentration calculation device that calculates the concentration of blood flowing through the tube 100 constituting the blood flow circuit of the artificial dialysis device (that is, blood flow concentration) will be described. . However, the concentration calculation device is an arbitrary device that calculates the concentration of blood flowing in a blood vessel of a living body or the concentration of any fluid other than blood flowing in an arbitrary tube (for example, ink, oil, sewage, seasoning, etc.). You may apply to a density | concentration calculation apparatus.
　（１）第１実施例
　はじめに、図１から図８を参照しながら、第１実施例の濃度算出装置１について説明を進める。 (1) First Example First , the concentration calculation apparatus 1 of the first example will be described with reference to FIGS.
　（１－１）濃度算出装置の構成
　はじめに、図１を参照しながら、第１実施例の濃度算出装置１の構成について説明する。図１は、第１実施例の濃度算出装置１の構成を示すブロック図である。 (1-1) Configuration of Concentration Calculation Device First, the configuration of the concentration calculation device 1 of the first embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of the concentration calculation apparatus 1 of the first embodiment.
　図１に示すように、第１実施例の濃度算出装置１は、レーザ素子１１と、受光素子１２と、増幅器１３と、演算回路１４とを備えている。 As shown in FIG. 1, the concentration calculation apparatus 1 of the first embodiment includes a laser element 11, a light receiving element 12, an amplifier 13, and an arithmetic circuit 14.
　レーザ素子１１は、「照射手段」の一具体例を構成しており、チューブ１００に対してレーザ光ＬＢを照射する。このとき、レーザ素子１１は、チューブ１００内の流路１０１（つまり、血液が流れている流路１０１）に対してレーザ光ＬＢを照射することが好ましい。尚、第１実施例では、流路１０１は、樹脂製の又はガラス製の透明な又は半透明な側壁１０２によって取り囲まれている。 The laser element 11 constitutes a specific example of “irradiation means” and irradiates the tube 100 with the laser beam LB. At this time, it is preferable that the laser element 11 irradiates the laser beam LB with respect to the flow channel 101 in the tube 100 (that is, the flow channel 101 in which blood flows). In the first embodiment, the flow path 101 is surrounded by a transparent or translucent side wall 102 made of resin or glass.
　尚、チューブ１００は、濃度算出装置１に対して、着脱可能（言い換えれば、交換可能）な状態で取り付けられることが好ましい。言い換えれば、チューブ１００は、濃度算出装置１に対して、着脱不可能な状態で取り付けられてもよい。 The tube 100 is preferably attached to the concentration calculation device 1 in a detachable (in other words, replaceable) state. In other words, the tube 100 may be attached to the concentration calculation device 1 in a non-detachable state.
　受光素子１２は、「受光手段」の一具体例を構成しており、チューブ１００に照射されたレーザ光ＬＢの散乱光を受光する。受光素子１２が受光する散乱光には、チューブ１００内を流れる血液（特に、当該血液に含まれる、移動している散乱体である血球）によって散乱された散乱光や、静止している組織（例えば、チューブ１００自体）によって散乱された散乱光が含まれている。受光素子１２は、受光した散乱光を電気信号に変換することで得られる受光信号を生成する。 The light receiving element 12 constitutes a specific example of “light receiving means”, and receives the scattered light of the laser light LB irradiated on the tube 100. The scattered light received by the light receiving element 12 includes scattered light scattered by blood flowing in the tube 100 (particularly, blood cells that are moving scatterers contained in the blood) and stationary tissue ( For example, scattered light scattered by the tube 100 itself) is included. The light receiving element 12 generates a received light signal obtained by converting the received scattered light into an electrical signal.
　増幅器１３は、受光素子１２から出力される電流信号である受光信号を、電圧信号に変換した上で増幅する。 The amplifier 13 amplifies the light receiving signal, which is a current signal output from the light receiving element 12, after converting it into a voltage signal.
　演算回路１４は、増幅器１３の出力（つまり、受光素子１２が受光した散乱光に応じた受光信号）に基づいて、チューブ１００内を流れる血液の濃度（血流濃度）Ｎを算出する。血流濃度Ｎを算出するために、演算回路１４は、ＬＰＦ（Low Pass Filter）１４１と、Ａ／Ｄコンバータ１４２と、演算器１４３とを備えている。 The arithmetic circuit 14 calculates the concentration (blood flow concentration) N of the blood flowing in the tube 100 based on the output of the amplifier 13 (that is, the light reception signal corresponding to the scattered light received by the light receiving element 12). In order to calculate the blood flow concentration N, the arithmetic circuit 14 includes an LPF (Low Pass Filter) 141, an A / D converter 142, and a calculator 143.
　ＬＰＦ１４１は、増幅器１３の出力（つまり、受光素子１２が受光した散乱光に応じた受光信号）に含まれる信号成分のうち低域信号成分以外の他の周波数帯域の信号成分をカットする。その結果、ＬＰＦ１４１は、増幅器１３の出力に含まれる信号成分のうちの低域信号成分に相当する光強度信号を、Ａ／Ｄコンバータ１４２に出力する。尚、光強度信号は、受光素子１２が受光した散乱光の光強度（例えば、平均的な光強度）を直接的に又は間接的に示す信号である。 The LPF 141 cuts signal components in frequency bands other than the low-frequency signal component among the signal components included in the output of the amplifier 13 (that is, the light-receiving signal corresponding to the scattered light received by the light-receiving element 12). As a result, the LPF 141 outputs a light intensity signal corresponding to a low-frequency signal component among the signal components included in the output of the amplifier 13 to the A / D converter 142. The light intensity signal is a signal that directly or indirectly indicates the light intensity (for example, average light intensity) of scattered light received by the light receiving element 12.
　尚、光強度信号は、例えば１ｋＨｚ以下の周波数の信号成分であることが多い。従って、ＬＰＦ１４１は、少なくとも光強度信号を透過する一方で光強度信号よりも高い周波数（例えば、１ｋＨｚ以上）の信号成分をカットすることが可能なカットオフ周波数を有していることが好ましい。 The light intensity signal is often a signal component having a frequency of 1 kHz or less, for example. Therefore, it is preferable that the LPF 141 has a cutoff frequency capable of cutting a signal component having a frequency higher than the light intensity signal (for example, 1 kHz or more) while transmitting at least the light intensity signal.
　Ａ／Ｄコンバータ１４２は、ＬＰＦ１４１から出力される光強度信号に対してＡ／Ｄ変換処理（つまり、量子化処理）を行う。その結果、Ａ／Ｄコンバータ１４２は、受光素子１２が受光した散乱光に応じた電圧信号に含まれている光強度信号のサンプル値（つまり、量子化された光強度信号）を、演算回路１４３に出力する。 The A / D converter 142 performs A / D conversion processing (that is, quantization processing) on the light intensity signal output from the LPF 141. As a result, the A / D converter 142 calculates the sample value (that is, the quantized light intensity signal) of the light intensity signal included in the voltage signal corresponding to the scattered light received by the light receiving element 12 as the arithmetic circuit 143. Output to.
　演算回路１４３は、「算出手段」の一具体例を構成しており、Ａ／Ｄコンバータ１４２の出力（つまり、受光素子１２が受光した散乱光に応じた電圧信号に含まれている光強度信号のサンプル値）に基づいて、血流濃度Ｎを算出する。 The arithmetic circuit 143 constitutes a specific example of “calculation means”, and the output of the A / D converter 142 (that is, the light intensity signal included in the voltage signal corresponding to the scattered light received by the light receiving element 12). The blood flow concentration N is calculated based on the sample value.
　尚、演算器１４３が算出した血流濃度Ｎは、濃度算出装置１の外部に（或いは、濃度算出装置１が内部に備える不図示の処理ブロックに）対して適切なタイミングで出力されてもよい。 The blood flow concentration N calculated by the calculator 143 may be output to the outside of the concentration calculation device 1 (or to a processing block (not shown) provided in the concentration calculation device 1) at an appropriate timing. .
　（１－２）濃度算出装置の動作
　続いて、図２を参照して、第１実施例の濃度算出装置１の動作の流れについて説明する。図２は、第１実施例の濃度算出装置１の動作の流れを示すフローチャートである。 (1-2) Operation of Density Calculation Device Next, the flow of operation of the concentration calculation device 1 of the first embodiment will be described with reference to FIG. FIG. 2 is a flowchart showing an operation flow of the concentration calculation apparatus 1 of the first embodiment.
　図２に示すように、レーザ素子１１は、チューブ１００に対してレーザ光ＬＢを照射する（ステップＳ１１）。このとき、レーザ素子１１は、チューブ１００内の流路１０１（つまり、血液が流れている流路１０１）に対してレーザ光ＬＢを照射することが好ましい。 As shown in FIG. 2, the laser element 11 irradiates the tube 100 with the laser beam LB (step S11). At this time, it is preferable that the laser element 11 irradiates the laser beam LB with respect to the flow channel 101 in the tube 100 (that is, the flow channel 101 in which blood flows).
　ここで、図３を参照して、チューブ１００に対するレーザ光ＬＢの照射の具体的態様について説明する。図３は、チューブ１００に対するレーザ光ＬＢの照射の具体的態様を示す断面図である。 Here, with reference to FIG. 3, the specific aspect of irradiation of the laser beam LB with respect to the tube 100 is demonstrated. FIG. 3 is a cross-sectional view illustrating a specific mode of irradiation of the tube 100 with the laser beam LB.
　図３（ａ）から図３（ｃ）に示すように、レーザ素子１１は、チューブ１００内でのレーザ光ＬＢのファーフィールドパターンＦＦＰ（つまり、楕円状のパターン）が、当該ファーフィールドパターンＦＦＰの投影面のうちの流路１０１に相当する領域部分に形成されるように、レーザ光ＬＢを照射する。加えて、レーザ素子１１は、チューブ１００内でのレーザ光ＬＢのファーフィールドパターンＦＦＰが、当該ファーフィールドパターンＦＦＰの投影面のうちの側壁１０２に相当する領域部分に形成されないように、レーザ光ＬＢを照射する。つまり、レーザ素子１１は、チューブ１００内でのレーザ光ＬＢのファーフィールドパターンＦＦＰの全てが、当該ファーフィールドパターンＦＦＰの投影面のうちの流路１０１に相当する領域部分に形成されるように、レーザ光ＬＢを照射する。 As shown in FIG. 3A to FIG. 3C, the laser element 11 has a far field pattern FFP (that is, an elliptical pattern) of the laser light LB in the tube 100 in the far field pattern FFP. The laser beam LB is irradiated so as to be formed in a region corresponding to the flow path 101 in the projection surface. In addition, the laser element 11 has a laser beam LB so that the far field pattern FFP of the laser beam LB in the tube 100 is not formed in a region corresponding to the side wall 102 in the projection surface of the far field pattern FFP. Irradiate. That is, the laser element 11 is formed so that all of the far field pattern FFP of the laser light LB in the tube 100 is formed in a region corresponding to the flow path 101 in the projection surface of the far field pattern FFP. Irradiate with laser beam LB.
　言い換えれば、レーザ素子１１は、レーザ光ＬＢの光軸に沿って左右方向及び前後方向に分布する流路１０１（つまり、レーザ光ＬＢの光軸又は光路上に分布している流路１０１）にレーザ光ＬＢが照射されるように、レーザ光ＬＢを照射する。加えて、レーザ素子１１は、レーザ光ＬＢの光軸に沿って左右方向に分布する側壁１０２（つまり、レーザ光ＬＢの光軸又は光路上に分布していない側壁１０２）にレーザ光ＬＢが照射されないように、レーザ光ＬＢを照射する。但し、レーザ光ＬＢがチューブ１００の内部の血液に照射される以上、レーザ光ＬＢは、当該レーザ光ＬＢの光軸に沿って前後方向に分布する側壁１０２（つまり、レーザ光ＬＢの光軸又は光路上に分布する側壁１０２）には照射されてもよい。尚、図３（ａ）から図３（ｃ）において、レーザ光ＬＢの光軸は、紙面奥側から紙面手前側に向かう方向又は紙面手前側から紙面奥側に向かう方向に沿った軸となる。 In other words, the laser element 11 is disposed in the flow paths 101 distributed in the left-right direction and the front-rear direction along the optical axis of the laser light LB (that is, the flow paths 101 distributed on the optical axis or the optical path of the laser light LB). The laser beam LB is irradiated so that the laser beam LB is irradiated. In addition, the laser element 11 irradiates the side wall 102 distributed in the left-right direction along the optical axis of the laser beam LB (that is, the side wall 102 not distributed on the optical axis or optical path of the laser beam LB) with the laser beam LB. The laser beam LB is irradiated so as not to occur. However, as long as the laser beam LB is irradiated on the blood inside the tube 100, the laser beam LB is distributed in the front-rear direction along the optical axis of the laser beam LB (that is, the optical axis or the laser beam LB). The side wall 102) distributed on the optical path may be irradiated. 3A to 3C, the optical axis of the laser beam LB is an axis along the direction from the back side of the paper to the front side of the paper or the direction from the front side of the paper to the back side of the paper. .
　より具体的には、図３（ａ）に示すように、レーザ素子１１は、ファーフィールドパターンＦＦＰの長軸が流路の中心軸と交わるように、レーザ光ＬＢを照射してもよい。 More specifically, as shown in FIG. 3A, the laser element 11 may irradiate the laser beam LB so that the long axis of the far field pattern FFP intersects the central axis of the flow path.
　好ましくは、図３（ｂ）に示すように、レーザ素子１１は、ファーフィールドパターンＦＦＰの長軸が流路の中心軸と平行になるように、レーザ光ＬＢを照射してもよい。より好ましくは、図３（ｂ）に示すように、レーザ素子１１は、ファーフィールドパターンＦＦＰの長軸が流路の中心軸と一致するように、レーザ光ＬＢを照射してもよい。 Preferably, as shown in FIG. 3B, the laser element 11 may irradiate the laser beam LB so that the long axis of the far field pattern FFP is parallel to the central axis of the flow path. More preferably, as shown in FIG. 3B, the laser element 11 may irradiate the laser beam LB so that the long axis of the far field pattern FFP coincides with the central axis of the flow path.
　或いは、図３（ｃ）に示すように、レーザ素子１１は、ファーフィールドパターンＦＦＰの長軸が流路の中心軸に直交するように、レーザ光ＬＢを照射してもよい。 Alternatively, as shown in FIG. 3C, the laser element 11 may irradiate the laser beam LB so that the long axis of the far field pattern FFP is orthogonal to the central axis of the flow path.
　尚、濃度算出装置１に対してチューブ１００が取り付けられた時点で、上述した態様でレーザ光ＬＢが照射されるようにレーザ素子１１が設定されることが好ましい。例えば、取り付けられたチューブ１００の外径やチューブ１００の内径や側壁１０２の屈折率等に応じて、レーザ素子１１の取り付け角度等が適宜設定されることが好ましい。加えて、レーザ素子１１と受光素子１２との間の距離（例えば、光学距離）は、濃度検出装置１に取り付けられるチューブ１００の外径の最大値に合わせて適切な距離に設定されていることが好ましい。 In addition, it is preferable that the laser element 11 is set so that the laser beam LB is irradiated in the above-described manner when the tube 100 is attached to the concentration calculation apparatus 1. For example, it is preferable to appropriately set the attachment angle of the laser element 11 according to the outer diameter of the attached tube 100, the inner diameter of the tube 100, the refractive index of the side wall 102, and the like. In addition, the distance (for example, optical distance) between the laser element 11 and the light receiving element 12 is set to an appropriate distance according to the maximum value of the outer diameter of the tube 100 attached to the concentration detection device 1. Is preferred.
　再び図２において、その後、受光素子１２は、チューブ１００からのレーザ光ＬＢの散乱光を受光する（ステップＳ１２）。より具体的には、受光素子１２は、チューブ１００内を流れる血液（特に、当該血液に含まれる、移動している散乱体である血球）によって散乱された散乱光や、静止している組織（例えば、チューブ１００自体）によって散乱された散乱光を受光する。尚、散乱光として、チューブ１００に照射されたレーザ光ＬＢの透過光に相当する前方散乱光が用いられてもよいし、チューブ１００に照射されたレーザ光ＬＢの反射光に相当する後方散乱光が用いられてもよい。 In FIG. 2 again, thereafter, the light receiving element 12 receives the scattered light of the laser light LB from the tube 100 (step S12). More specifically, the light receiving element 12 includes scattered light scattered by blood flowing in the tube 100 (particularly, blood cells that are moving scatterers contained in the blood) and stationary tissue ( For example, the scattered light scattered by the tube 100 itself is received. As the scattered light, forward scattered light corresponding to the transmitted light of the laser light LB irradiated to the tube 100 may be used, or back scattered light corresponding to the reflected light of the laser light LB irradiated to the tube 100. May be used.
　その後、受光素子１２は、受光した散乱光を電気信号に変換することで得られる受光信号を生成する（ステップＳ１２）。その後、受光素子１２は、生成した受光信号を、増幅器１３に出力する。受光信号には、散乱光の光強度に相当する信号成分（つまり、上述した光強度信号であって、相対的に低域の信号成分）が含まれている。 Thereafter, the light receiving element 12 generates a light receiving signal obtained by converting the received scattered light into an electric signal (step S12). Thereafter, the light receiving element 12 outputs the generated light reception signal to the amplifier 13. The received light signal includes a signal component corresponding to the light intensity of the scattered light (that is, the above-described light intensity signal and a relatively low-frequency signal component).
　その後、増幅器１３は、受光素子１２から出力される受光信号（つまり、受光素子１２が受光した散乱光に応じた受光信号）を、電圧信号に変換した上で増幅する（ステップＳ１３）。その後、増幅器１３は、増幅した受光信号を演算回路１４に出力する。より具体的には、増幅器１３は、増幅した受光信号を、ＬＰＦ１４１に出力する。 Thereafter, the amplifier 13 converts the received light signal output from the light receiving element 12 (that is, the received light signal corresponding to the scattered light received by the light receiving element 12) into a voltage signal and amplifies it (step S13). Thereafter, the amplifier 13 outputs the amplified light reception signal to the arithmetic circuit 14. More specifically, the amplifier 13 outputs the amplified light reception signal to the LPF 141.
　その後、ＬＰＦ１４１は、増幅器１３から出力される受光信号に含まれる信号成分のうち、低域信号成分以外の他の周波数帯域の信号成分をカットする。その結果、ＬＰＦ１４１は、増幅器１３の出力に含まれる信号成分のうちの低域信号成分に相当する光強度信号を取得する（ステップＳ１４）。その後、ＬＰＦ１４１は、取得した光強度信号を、Ａ／Ｄコンバータ１４２に出力する。 After that, the LPF 141 cuts signal components in frequency bands other than the low-frequency signal component among the signal components included in the light reception signal output from the amplifier 13. As a result, the LPF 141 acquires a light intensity signal corresponding to the low-frequency signal component among the signal components included in the output of the amplifier 13 (step S14). Thereafter, the LPF 141 outputs the acquired light intensity signal to the A / D converter 142.
　その後、Ａ／Ｄコンバータ１４２は、ＬＰＦ１４１から出力される光強度信号に対してＡ／Ｄ変換処理（つまり、量子化処理）を行う（ステップＳ１５）。具体的には、例えば、Ａ／Ｄコンバータ１４２は、Ａ／Ｄコンバータ１４２のサンプリング周期をＴａ１とすると、周期Ｔａ１毎に、光強度信号のサンプル値（つまり、量子化された光強度信号）を出力する。その後、Ａ／Ｄコンバータ１４２は、受光素子１２が受光した散乱光の光強度に応じた光強度信号のサンプル値（つまり、量子化された光強度信号）を、演算器１４３に出力する。 Thereafter, the A / D converter 142 performs A / D conversion processing (that is, quantization processing) on the light intensity signal output from the LPF 141 (step S15). Specifically, for example, when the sampling period of the A / D converter 142 is Ta1, the A / D converter 142 calculates a sample value of the light intensity signal (that is, a quantized light intensity signal) for each period Ta1. Output. Thereafter, the A / D converter 142 outputs a sample value (that is, a quantized light intensity signal) of the light intensity signal corresponding to the light intensity of the scattered light received by the light receiving element 12 to the calculator 143.
　その後、演算器１４３は、Ａ／Ｄコンバータ１４２の出力（つまり受光素子１２が受光した散乱光の光強度に応じた光強度信号のサンプル値）に基づいて、血流濃度Ｎを算出する（ステップＳ１６）。 Thereafter, the calculator 143 calculates the blood flow concentration N based on the output of the A / D converter 142 (that is, the sample value of the light intensity signal corresponding to the light intensity of the scattered light received by the light receiving element 12) (step S1). S16).
　ここで、図４を参照して、光強度信号に基づく血流濃度Ｎの算出動作について説明する。図４は、受光素子１２がレーザ光ＬＢの前方散乱光を受光する場合の光強度信号と血流濃度Ｎとの間の相関関係及び受光素子１２がレーザ光ＬＢの後方散乱光を受光する場合の光強度信号と血流濃度Ｎとの間の相関関係を示すグラフである。 Here, with reference to FIG. 4, the calculation operation of the blood flow concentration N based on the light intensity signal will be described. FIG. 4 shows the correlation between the light intensity signal and the blood flow concentration N when the light receiving element 12 receives the forward scattered light of the laser light LB, and the case where the light receiving element 12 receives the back scattered light of the laser light LB. It is a graph which shows the correlation between the light intensity signal and blood flow concentration N.
　図４（ａ）は、受光素子１２がレーザ光ＬＢの前方散乱光を受光する場合の光強度信号（具体的には、光強度信号の信号レベル）と血流濃度Ｎとの間の相関関係を示している。受光素子１２がレーザ光ＬＢの前方散乱光を受光する場合には、血流濃度Ｎが高ければ高いほど、光強度信号の信号レベルは小さくなる。言い換えれば、受光素子１２がレーザ光ＬＢの前方散乱光を受光する場合には、血流濃度Ｎが低ければ低いほど、光強度信号の信号レベルは大きくなる。つまり、レーザ光ＬＢの透過を妨げる散乱体である血球が血液内に多く含まれていればいるほど、光強度信号は小さくなる。 4A shows a correlation between the light intensity signal (specifically, the signal level of the light intensity signal) and the blood flow concentration N when the light receiving element 12 receives the forward scattered light of the laser light LB. Is shown. When the light receiving element 12 receives the forward scattered light of the laser beam LB, the higher the blood flow concentration N, the smaller the signal level of the light intensity signal. In other words, when the light receiving element 12 receives the forward scattered light of the laser light LB, the signal level of the light intensity signal increases as the blood flow concentration N decreases. In other words, the more blood cells that are scatterers that hinder the transmission of the laser beam LB, the smaller the light intensity signal.
　演算器１４３は、受光素子１２がレーザ光ＬＢの前方散乱光を受光する場合には、演算器１４３の内部に又は外部に予め保持している図４（ａ）に示す相関情報を参照することで、Ａ／Ｄコンバータ１４２から出力される光強度信号に応じた血流濃度Ｎを算出する。例えば、Ａ／Ｄコンバータ１４２から出力される光強度信号がＰ１である場合には、演算器１４３は、「ＮＨ１」という血流濃度Ｎを算出する。一方で、Ａ／Ｄコンバータ１４２から出力される光強度信号がＰ２（但し、Ｐ１＜Ｐ２）である場合には、演算器１４３は、「ＮＬ１（但し、ＮＬ１＜ＮＨ１）」という血流濃度Ｎを算出する。 When the light receiving element 12 receives the forward scattered light of the laser beam LB, the computing unit 143 refers to the correlation information shown in FIG. 4A held in advance inside or outside the computing unit 143. Thus, the blood flow concentration N corresponding to the light intensity signal output from the A / D converter 142 is calculated. For example, when the light intensity signal output from the A / D converter 142 is P1, the calculator 143 calculates a blood flow concentration N of “NH1”. On the other hand, when the light intensity signal output from the A / D converter 142 is P2 (where P1 <P2), the calculator 143 determines the blood flow concentration N as “NL1 (where NL1 <NH1)”. Is calculated.
　一方で、図４（ｂ）は、受光素子１２がレーザ光ＬＢの後方散乱光を受光する場合の光強度信号（具体的には、光強度信号の信号レベル）と血流濃度Ｎとの間の相関関係を示している。受光素子１２がレーザ光ＬＢの後方散乱光を受光する場合には、血流濃度Ｎが高ければ高いほど、光強度信号の信号レベルは大きくなる。言い換えれば、受光素子１２がレーザ光ＬＢの後方散乱光を受光する場合には、血流濃度Ｎが低ければ低いほど、光強度信号の信号レベルは小さくなる。つまり、レーザ光ＬＢを反射させる散乱体である血球が血液内に多く含まれていればいるほど、光強度信号は大きくなる。 On the other hand, FIG. 4B shows the relationship between the light intensity signal (specifically, the signal level of the light intensity signal) and the blood flow concentration N when the light receiving element 12 receives the backscattered light of the laser light LB. The correlation is shown. When the light receiving element 12 receives the back scattered light of the laser beam LB, the signal level of the light intensity signal increases as the blood flow concentration N increases. In other words, when the light receiving element 12 receives the backscattered light of the laser light LB, the signal level of the light intensity signal becomes smaller as the blood flow concentration N is lower. That is, the more the blood cells, which are scatterers that reflect the laser beam LB, are contained in the blood, the greater the light intensity signal.
　演算器１４３は、受光素子１２がレーザ光ＬＢの後方散乱光を受光する場合には、演算器１４３の内部に又は外部に予め保持している図４（ｂ）に示す相関情報を参照することで、Ａ／Ｄコンバータ１４２から出力される光強度信号に応じた血流濃度Ｎを算出する。例えば、Ａ／Ｄコンバータ１４２から出力される光強度信号がＰ１である場合には、演算器１４３は、「ＮＬ２」という血流濃度Ｎを算出する。一方で、Ａ／Ｄコンバータ１４２から出力される光強度信号がＰ２（但し、Ｐ１＜Ｐ２）である場合には、演算器１４３は、「ＮＨ２（但し、ＮＬ２＜ＮＨ２）」という血流濃度Ｎを算出する。 When the light receiving element 12 receives the back scattered light of the laser beam LB, the computing unit 143 refers to the correlation information shown in FIG. 4B held in advance inside or outside the computing unit 143. Thus, the blood flow concentration N corresponding to the light intensity signal output from the A / D converter 142 is calculated. For example, when the light intensity signal output from the A / D converter 142 is P1, the calculator 143 calculates a blood flow concentration N of “NL2”. On the other hand, when the light intensity signal output from the A / D converter 142 is P2 (where P1 <P2), the calculator 143 determines the blood flow concentration N as “NH2 (where NL2 <NH2)”. Is calculated.
　尚、図４（ａ）及び図４（ｂ）は、光強度信号と血流濃度Ｎとの間の相関関係をグラフで示す例を示している。しかしながら、演算器１４３は、光強度信号と血流濃度Ｎとの間の相関関係を示すグラフに限らず、光強度信号と血流濃度Ｎとの間の相関関係を示す任意の情報（例えば、数式、テーブル、又はマップ等）を参照することで、Ａ／Ｄコンバータ１４２から出力される光信号強度に応じた血流濃度Ｎを算出してもよい。 4A and 4B show examples in which the correlation between the light intensity signal and the blood flow concentration N is shown in a graph. However, the calculator 143 is not limited to the graph indicating the correlation between the light intensity signal and the blood flow concentration N, and any information indicating the correlation between the light intensity signal and the blood flow concentration N (for example, The blood flow concentration N according to the intensity of the optical signal output from the A / D converter 142 may be calculated by referring to a mathematical formula, a table, a map, or the like.
　また、第１実施例では、演算器１４３は、図４（ａ）及び図４（ｂ）に示す光強度信号と血流濃度Ｎとの相関関係を示す相関情報に基づいて、血流濃度Ｎを算出している。従って、第１実施例における「血流濃度Ｎ」は、実質的には、血液に含まれている血球（つまり、散乱体としての血球）の濃度と同義である。但し、血流濃度Ｎとして、その他の濃度（例えば、血液に含まれている血球以外の物質の濃度等）が用いられてもよい。 Further, in the first embodiment, the computing unit 143 performs the blood flow concentration N based on the correlation information indicating the correlation between the light intensity signal and the blood flow concentration N shown in FIGS. 4 (a) and 4 (b). Is calculated. Therefore, the “blood flow concentration N” in the first embodiment is substantially synonymous with the concentration of blood cells contained in blood (that is, blood cells as scatterers). However, as the blood flow concentration N, other concentrations (for example, concentrations of substances other than blood cells contained in blood, etc.) may be used.
　（１－３）濃度算出装置の技術的効果
　続いて、図５から図８を参照しながら、第１実施例の濃度算出装置１の技術的効果について説明する。図５は、比較例の濃度算出装置におけるチューブ１００に対するレーザ光ＬＢの照射の具体的態様を示す断面図である。図６は、第１実施例の濃度算出装置１が取得する受光信号及び比較例の濃度算出装置が取得する受光信号を示すグラフである。図７は、第１実施例の濃度算出装置１が取得する受光信号を規格化することで得られる信号（規格化受光信号）及び比較例の濃度算出装置が取得する受光信号を規格化することで得られる信号（規格化受光信号）を示すグラフである。図８は、第１実施例の濃度算出装置１が取得する光強度信号を規格化することで得られる信号（規格化光強度信号）と血流濃度Ｎとの間の相関関係及び比較例の濃度算出装置が取得する光強度信号を規格化することで得られる信号（規格化光強度信号）と血流濃度Ｎとの間の相関関係を示すグラフである。 (1-3) Technical Effect of Concentration Calculation Device Next , the technical effect of the concentration calculation device 1 of the first embodiment will be described with reference to FIGS. FIG. 5 is a cross-sectional view showing a specific mode of irradiation of the laser beam LB onto the tube 100 in the concentration calculation apparatus of the comparative example. FIG. 6 is a graph showing a light reception signal acquired by the concentration calculation device 1 of the first embodiment and a light reception signal acquired by the concentration calculation device of the comparative example. FIG. 7 shows normalization of a signal (standardized light reception signal) obtained by normalizing the light reception signal acquired by the concentration calculation device 1 of the first embodiment and a light reception signal acquired by the concentration calculation device of the comparative example. It is a graph which shows the signal (standardization light reception signal) obtained by (3). FIG. 8 shows the correlation between the signal (normalized light intensity signal) obtained by normalizing the light intensity signal acquired by the concentration calculation apparatus 1 of the first embodiment and the blood flow concentration N and the comparative example. It is a graph which shows the correlation between the signal (normalized light intensity signal) obtained by normalizing the light intensity signal which a density | concentration calculation apparatus acquires, and the blood flow density | concentration N.
　図５（ａ）から図５（ｃ）に示すように、比較例の濃度算出装置は、チューブ１００内でのレーザ光ＬＢのファーフィールドパターンＦＦＰ（つまり、楕円状のパターン）が、当該ファーフィールドパターンＦＦＰの投影面のうちの流路１０１に相当する領域部分に形成されるように、レーザ光ＬＢを照射する。加えて、比較例の濃度算出装置は、チューブ１００内でのレーザ光ＬＢのファーフィールドパターンＦＦＰが、当該ファーフィールドパターンＦＦＰの投影面のうちの側壁１０２に相当する領域部分にも形成されるように、レーザ光ＬＢを照射する。 As shown in FIG. 5A to FIG. 5C, in the concentration calculation apparatus of the comparative example, the far field pattern FFP (that is, the elliptical pattern) of the laser beam LB in the tube 100 is the far field. The laser beam LB is irradiated so as to be formed in a region corresponding to the flow path 101 in the projection surface of the pattern FFP. In addition, in the concentration calculation apparatus of the comparative example, the far field pattern FFP of the laser light LB in the tube 100 is formed also in a region corresponding to the side wall 102 in the projection surface of the far field pattern FFP. Then, the laser beam LB is irradiated.
　言い換えれば、レーザ素子１１は、レーザ光ＬＢの光軸に沿って前後方向に分布する流路１０１（つまり、レーザ光ＬＢの光軸又は光路上に分布している流路１０１）にレーザ光ＬＢが照射されるように、レーザ光ＬＢを照射する。加えて、レーザ素子１１は、レーザ光ＬＢの光軸に沿って左右方向に分布する側壁１０２（つまり、レーザ光ＬＢの光軸又は光路上に分布していない側壁１０２）にもレーザ光ＬＢが照射されるように、レーザ光ＬＢを照射する。尚、図５（ａ）から図５（ｃ）において、図３（ａ）から図３（ｃ）と同様に、レーザ光ＬＢの光軸は、紙面奥側から紙面手前側に向かう方向又は紙面手前側から紙面奥側に向かう方向に沿った軸となる。 In other words, the laser element 11 transmits the laser light LB to the flow paths 101 distributed in the front-rear direction along the optical axis of the laser light LB (that is, the flow paths 101 distributed on the optical axis or the optical path of the laser light LB). Is irradiated with the laser beam LB. In addition, in the laser element 11, the laser beam LB is also applied to the side wall 102 distributed in the left-right direction along the optical axis of the laser beam LB (that is, the side wall 102 not distributed on the optical axis or optical path of the laser beam LB). The laser beam LB is irradiated so as to be irradiated. 5 (a) to 5 (c), the optical axis of the laser beam LB is the direction from the back side to the front side of the paper or the paper surface, as in FIGS. 3 (a) to 3 (c). It is an axis along the direction from the near side to the back side of the drawing.
　このような比較例の濃度算出装置と第１実施例の濃度算出装置との間の特性の違いを以下に説明する。 The difference in characteristics between the concentration calculation apparatus of the comparative example and the concentration calculation apparatus of the first embodiment will be described below.
　図６（ａ）は、血流濃度Ｎの変化を示す。図６（ａ）に示すように、血流濃度Ｎは、濃度変化点において、相対的に低い濃度から相対的に高い濃度に変わるものとする。 FIG. 6A shows the change in blood flow concentration N. FIG. As shown in FIG. 6A, the blood flow concentration N changes from a relatively low concentration to a relatively high concentration at the concentration change point.
　図６（ｂ）は、図６（ａ）に示す態様で血流濃度Ｎが変化する血液に対してレーザ光ＬＢを照射する場合であって、主として前方散乱光を受光するべく受光素子１２の受光点をレーザ素子１１の出射点とチューブ１００を介して対向して配置した場合に取得される受光信号の例を示す。図６（ｂ）に示すように、血流濃度が相対的に低い場合に取得される受光信号の信号強度は、血流濃度が相対的に高い場合に取得される受光信号の信号強度よりも大きくなる。 FIG. 6B shows a case where the laser light LB is irradiated to the blood whose blood flow concentration N changes in the mode shown in FIG. 6A, and the light receiving element 12 mainly receives forward scattered light. An example of the received light signal obtained when the light receiving point is arranged opposite to the emission point of the laser element 11 via the tube 100 is shown. As shown in FIG. 6B, the signal intensity of the received light signal acquired when the blood flow concentration is relatively low is higher than the signal intensity of the received light signal acquired when the blood flow concentration is relatively high. growing.
　しかしながら、比較例の濃度算出装置が取得する受光信号には、血液中の血球等の散乱体によって散乱された散乱光（ここでは、透過光に相当する前方散乱光）に応じた信号成分のみならず、レーザ光ＬＢの光軸に沿って左右方向に分布する側壁１０２に照射されたレーザ光ＬＢに起因した迷光に応じた信号成分（つまり、ＤＣオフセット成分）が含まれている。一方で、第１実施例の濃度算出装置１が取得する受光信号には、血液中の血球等の散乱体によって散乱された散乱光（ここでは、透過光に相当する前方散乱光）に応じた信号成分が含まれている一方で、レーザ光ＬＢの光軸に沿って左右方向に分布する側壁１０２に照射されたレーザ光ＬＢに起因した迷光に応じた信号成分（つまり、ＤＣオフセット成分）が殆ど含まれていない。従って、比較例の濃度算出装置が取得する受光信号の信号強度は、第１実施例の濃度算出装置１が取得する受信信号の信号強度よりも大きくなる。 However, the light reception signal acquired by the concentration calculation device of the comparative example includes only a signal component corresponding to scattered light (here, forward scattered light corresponding to transmitted light) scattered by a scatterer such as a blood cell in blood. First, a signal component (that is, a DC offset component) corresponding to the stray light caused by the laser beam LB irradiated to the side wall 102 distributed in the left-right direction along the optical axis of the laser beam LB is included. On the other hand, the light reception signal acquired by the concentration calculation apparatus 1 according to the first embodiment corresponds to scattered light (here, forward scattered light corresponding to transmitted light) scattered by a scatterer such as a blood cell in blood. While a signal component is included, a signal component (that is, a DC offset component) corresponding to stray light caused by the laser beam LB irradiated to the side wall 102 distributed in the left-right direction along the optical axis of the laser beam LB is present. It is hardly included. Therefore, the signal intensity of the received light signal acquired by the density calculation device of the comparative example is larger than the signal strength of the reception signal acquired by the density calculation device 1 of the first embodiment.
　図６（ｂ）に示すように、第１実施例の濃度算出装置１は、受光信号の信号強度の変化（つまり、光強度信号）の変化を監視することで、血流濃度Ｎを算出することができる。また、比較例の濃度算出装置もまた同様に、受光信号の信号強度の変化（つまり、光強度信号）の変化を監視することで、血流濃度Ｎを算出することができる。しかしながら、以下に説明するように、第１実施例の濃度算出装置１は、比較例の濃度算出装置と比較して、血流濃度Ｎの算出分解能を向上させることができるという実践上大変有益な効果を有している。以下、血流濃度Ｎの算出分解能について説明を進める。 As shown in FIG. 6B, the concentration calculation apparatus 1 of the first embodiment calculates the blood flow concentration N by monitoring the change in the signal intensity of the received light signal (that is, the light intensity signal). be able to. Similarly, the concentration calculation apparatus of the comparative example can also calculate the blood flow concentration N by monitoring the change in the signal intensity of the received light signal (that is, the light intensity signal). However, as will be described below, the concentration calculation device 1 of the first embodiment is very useful in practice that the calculation resolution of the blood flow concentration N can be improved as compared with the concentration calculation device of the comparative example. Has an effect. Hereinafter, the calculation resolution of the blood flow concentration N will be described.
　図７は、図６（ｂ）に示す受光信号を、時刻ｔ１の時点で比較例の濃度算出装置が取得する受光信号で規格化することで得られる信号（規格化受光信号）を示す。図７に示すように、同じ変化量だけ変化する血流濃度Ｎに対して、第１実施例の濃度算出装置１が取得する規格化受光信号の信号強度の変化量は、比較例の濃度算出装置が取得する規格化受光信号の信号強度の変化量よりも大きくなる。 FIG. 7 shows a signal (standardized light reception signal) obtained by normalizing the light reception signal shown in FIG. 6B with the light reception signal acquired by the concentration calculation device of the comparative example at time t1. As shown in FIG. 7, for the blood flow concentration N that changes by the same amount of change, the amount of change in the signal intensity of the standardized light reception signal acquired by the concentration calculation device 1 of the first embodiment is the concentration calculation of the comparative example. It becomes larger than the change amount of the signal intensity of the standardized light reception signal acquired by the apparatus.
　このような規格化受信信号の信号強度の変化を考慮すれば、比較例の濃度算出装置が相対的に小さな血流濃度Ｎの変化を算出することが困難である一方で、第１実施例の濃度算出装置１は相対的に小さな血流濃度Ｎの変化をも算出することができる。というのも、比較例の濃度算出装置では、迷光に起因した信号成分（ＤＣオフセット成分）が受光信号に重畳されているがゆえに、第１実施例の濃度算出装置１と比較して、増幅器１３のゲインを大きくすると増幅器１３が飽和しやすくなってしまう。一方で、第１実施例の濃度算出装置１では、迷光に起因した信号成分（ＤＣオフセット成分）が受光信号に殆ど重畳されていないがゆえに、比較例の濃度算出装置と比較して、増幅器１３のゲインを大きくしたとしても増幅器１３が飽和しにくい。つまり、第１実施例の濃度算出装置１は、比較例の濃度算出装置と比較して、増幅器１３のゲインをより一層大きくすることができる。従って、第１実施例の濃度算出装置１は、比較例の濃度算出装置と比較して、受信信号の信号強度の変化（特に、相対的に小さい変化）を算出しやすくなる。このため、第１実施例の濃度算出装置１によって実現される血流濃度Ｎの算出分解能は、比較例の濃度算出装置によって実現される血流濃度Ｎの算出分解能よりも向上する。 Considering such a change in the signal strength of the standardized reception signal, it is difficult for the concentration calculation device of the comparative example to calculate a relatively small change in the blood flow concentration N. On the other hand, The concentration calculation device 1 can also calculate a relatively small change in blood flow concentration N. This is because, in the concentration calculation device of the comparative example, the signal component (DC offset component) caused by stray light is superimposed on the received light signal, so that the amplifier 13 is compared with the concentration calculation device 1 of the first embodiment. When the gain is increased, the amplifier 13 is likely to be saturated. On the other hand, in the concentration calculation apparatus 1 of the first embodiment, since the signal component (DC offset component) caused by stray light is hardly superimposed on the light reception signal, the amplifier 13 is compared with the concentration calculation apparatus of the comparative example. Even if the gain is increased, the amplifier 13 is not easily saturated. That is, the concentration calculation apparatus 1 of the first embodiment can further increase the gain of the amplifier 13 as compared with the concentration calculation apparatus of the comparative example. Therefore, the concentration calculation apparatus 1 of the first embodiment can easily calculate a change in signal strength of the received signal (particularly a relatively small change) as compared with the concentration calculation apparatus of the comparative example. For this reason, the calculation resolution of the blood flow concentration N realized by the concentration calculation device 1 of the first embodiment is higher than the calculation resolution of the blood flow concentration N realized by the concentration calculation device of the comparative example.
　算出分解能の向上は、光強度信号を規格化することで得られる信号（規格化光強度信号）と血流濃度Ｎとの間の相関関係を示す図８からも明らかである。図８に示すように、同じ変化量だけ変化する血流濃度Ｎに対して、第１実施例の濃度算出装置１が取得する規格化光強度信号の変化量は、比較例の濃度算出装置が取得する規格化光強度信号の信号強度の変化量よりも大きくなる。 The improvement in the calculation resolution is also apparent from FIG. 8 showing the correlation between the signal obtained by normalizing the light intensity signal (standardized light intensity signal) and the blood flow concentration N. As shown in FIG. 8, the change amount of the normalized light intensity signal acquired by the concentration calculation device 1 of the first embodiment with respect to the blood flow concentration N that changes by the same change amount is determined by the concentration calculation device of the comparative example. It becomes larger than the change amount of the signal intensity of the standardized light intensity signal to be acquired.
　以上説明したように、第１実施例の濃度算出装置１は、チューブ１００内でのレーザ光ＬＢのファーフィールドパターンＦＦＰが、当該ファーフィールドパターンＦＦＰの投影面のうちの側壁１０２に相当する領域部分に形成されないように、レーザ光ＬＢを照射する。このため、第１実施例の濃度算出装置１は、比較例の濃度算出装置と比較して、血流濃度Ｎの算出分解能を相対的に向上させることができる。 As described above, in the concentration calculation apparatus 1 of the first embodiment, the region portion in which the far field pattern FFP of the laser light LB in the tube 100 corresponds to the side wall 102 of the projection surface of the far field pattern FFP. The laser beam LB is irradiated so as not to be formed. For this reason, the concentration calculation device 1 of the first embodiment can relatively improve the calculation resolution of the blood flow concentration N as compared with the concentration calculation device of the comparative example.
　尚、濃度算出装置１は、チューブ１００内の投影面上においてファーフィールドパターンＦＦＰを形成すれば足りる。従って、濃度算出装置１は、ニアフィールドパターンを形成することで血流濃度Ｎを算出する濃度算出装置とは異なり、レーザ素子１１とチューブ１００との間に、コリメータレンズ等の光学系を備えていなくともよい。従って、濃度算出装置１のコストが低減される。加えて、濃度算出装置１が光学系を備えていない場合には、チューブ１００の交換に伴う光学系の焦点調整等が不要になるため、血流濃度Ｎの算出対象となるチューブ１００の交換が容易になる。一方で、濃度算出装置１がファーフィールドパターンＦＦＰを形成することで血流濃度Ｎを算出する場合であっても、上述したように、レーザ光ＬＢの光軸に沿って左右方向に分布する側壁１０２にレーザ光ＬＢが照射されることはない。このため、濃度算出装置１がファーフィールドパターンＦＦＰを形成することで血流濃度Ｎを算出する場合であっても、血流濃度Ｎの算出分解能が大きく低下することは殆ど又は全くない。従って、血流濃度Ｎの算出のためにファーフィールドパターンＦＦＰを採用することでコストの低減及びチューブ１００の容易な交換を実現しつつも、血流濃度Ｎの算出分解能を維持する（言い換えれば、大幅な低下を抑制する）ことができるという点で、第１実施例の濃度算出装置１は実践上大変有益である。 Note that it is sufficient for the concentration calculation apparatus 1 to form the far field pattern FFP on the projection surface in the tube 100. Therefore, unlike the concentration calculation device that calculates the blood flow concentration N by forming a near-field pattern, the concentration calculation device 1 includes an optical system such as a collimator lens between the laser element 11 and the tube 100. Not necessary. Therefore, the cost of the concentration calculation device 1 is reduced. In addition, when the concentration calculation apparatus 1 does not include an optical system, it is not necessary to adjust the focus of the optical system when the tube 100 is replaced. It becomes easy. On the other hand, even when the concentration calculation device 1 calculates the blood flow concentration N by forming the far field pattern FFP, as described above, the side wall distributed in the left-right direction along the optical axis of the laser beam LB. 102 is not irradiated with the laser beam LB. For this reason, even when the concentration calculation apparatus 1 calculates the blood flow concentration N by forming the far field pattern FFP, the calculation resolution of the blood flow concentration N is hardly reduced or not at all. Therefore, by adopting the far field pattern FFP for calculating the blood flow concentration N, the calculation resolution of the blood flow concentration N is maintained while reducing the cost and easily replacing the tube 100 (in other words, The concentration calculation apparatus 1 of the first embodiment is very useful in practice in that it can suppress a significant decrease).
　（２）第２実施例
　続いて、図９から図１０を参照しながら、第２実施例の濃度算出装置２について説明を進める。尚、以下の説明では、第１実施例の濃度算出装置１と同一の構成及び動作については、同一の参照符号及びステップ番号を付してその詳細な説明を省略する。 (2) Second Example Next, the concentration calculation apparatus 2 of the second example will be described with reference to FIGS. In the following description, the same configuration and operation as those of the concentration calculation apparatus 1 of the first embodiment are denoted by the same reference numerals and step numbers, and detailed description thereof is omitted.
　（２－１）濃度算出装置の構成
　はじめに、図９を参照しながら、第２実施例の濃度算出装置２の構成について説明する。図９は、第２実施例の濃度算出装置２の構成を示すブロック図である。 (2-1) Configuration of Concentration Calculation Device First, the configuration of the concentration calculation device 2 of the second embodiment will be described with reference to FIG. FIG. 9 is a block diagram showing the configuration of the concentration calculation apparatus 2 of the second embodiment.
　図９に示すように、第２実施例の濃度算出装置２は、第１実施例の濃度算出装置１と同様に、レーザ素子１１と、受光素子１２と、増幅器１３とを備えている。第２実施例の濃度算出装置２は、第１実施例の濃度算出装置１と比較して、受光素子２２と、増幅器２３とを更に備えているという点で異なっている。 As shown in FIG. 9, the concentration calculation apparatus 2 of the second embodiment includes a laser element 11, a light receiving element 12, and an amplifier 13, as in the concentration calculation apparatus 1 of the first embodiment. The concentration calculation device 2 of the second embodiment is different from the concentration calculation device 1 of the first embodiment in that it further includes a light receiving element 22 and an amplifier 23.
　加えて、第２実施例の濃度算出装置２は更に、演算回路２４を備えている。第２実施例の演算回路２４は、第１実施例の演算回路１４と比較して、ＨＰＦ２４４と、Ａ／Ｄコンバータ２４５と、演算器２４６とを更に備えているという点で異なっている。 In addition, the concentration calculation device 2 of the second embodiment further includes an arithmetic circuit 24. The arithmetic circuit 24 of the second embodiment is different from the arithmetic circuit 14 of the first embodiment in that it further includes an HPF 244, an A / D converter 245, and an arithmetic unit 246.
　第２実施例の濃度算出装置２が備えるその他の構成要素は、第１実施例の濃度算出装置１が備えるその他の構成要素と同一であってもよい。 Other components included in the concentration calculation device 2 of the second embodiment may be the same as other components included in the concentration calculation device 1 of the first embodiment.
　受光素子２２は、チューブ１００に照射されたレーザ光ＬＢの散乱光を受光する。受光素子２２は、受光した散乱光を電気信号に変換することで得られる受光信号を生成する。 The light receiving element 22 receives the scattered light of the laser beam LB irradiated on the tube 100. The light receiving element 22 generates a received light signal obtained by converting the received scattered light into an electrical signal.
　増幅器２３は、受光素子２２から出力される電流信号である受光信号を、電圧信号に変換した上で増幅する。 The amplifier 23 amplifies the light receiving signal, which is a current signal output from the light receiving element 22, after converting it into a voltage signal.
　ＨＰＦ２４４は、増幅器２３の出力（つまり、受光素子２２が受光した散乱光に応じた受光信号）に含まれる信号成分のうち高域信号成分以外の他の周波数帯域の信号成分をカットする。その結果、ＨＰＦ２４４は、増幅器２３の出力に含まれる信号成分のうちの高域信号成分に相当するビート信号を、Ａ／Ｄコンバータ２４５に出力する。尚、ＨＰＦ２４４が取り出すビート信号は、例えば、移動している散乱体である血球によって散乱された散乱光と静止している組織によって散乱された散乱光との相互干渉によって生ずる光ビート信号である。 The HPF 244 cuts signal components in frequency bands other than the high-frequency signal component among the signal components included in the output of the amplifier 23 (that is, the received light signal corresponding to the scattered light received by the light receiving element 22). As a result, the HPF 244 outputs to the A / D converter 245 a beat signal corresponding to the high frequency signal component of the signal components included in the output of the amplifier 23. The beat signal extracted by the HPF 244 is, for example, an optical beat signal generated by mutual interference between scattered light scattered by blood cells that are moving scatterers and scattered light scattered by a stationary tissue.
　尚、ビート信号は、例えば１ｋＨｚ以上の周波数の信号成分であることが多い。従って、ＨＰＦ２４４は、少なくともビート信号を透過する一方でビート信号よりも低い周波数（例えば、１ｋＨｚ以下）の信号成分をカットすることが可能なカットオフ周波数を有していることが好ましい。但し、ＨＰＦ２４４に代えて、少なくともビート信号を透過する一方でビート信号の周波数よりも高い周波数の信号成分及びビート信号の周波数よりも低い周波数の信号成分の双方をカットすることが可能なＢＰＦ（Band Pass Filter）が用いられてもよい。 The beat signal is often a signal component having a frequency of 1 kHz or more, for example. Therefore, it is preferable that the HPF 244 has a cut-off frequency capable of cutting a signal component having a frequency (for example, 1 kHz or less) lower than that of the beat signal while transmitting at least the beat signal. However, instead of the HPF 244, a BPF (Band capable of cutting both a signal component having a frequency higher than the frequency of the beat signal and a signal component having a frequency lower than the frequency of the beat signal while transmitting at least the beat signal. Pass Filter) may be used.
　Ａ／Ｄコンバータ２４５は、ＨＰＦ２４４から出力されるビート信号に対してＡ／Ｄ変換処理（つまり、量子化処理）を行う。その結果、Ａ／Ｄコンバータ２４５は、受光素子２２が受光した散乱光に応じた電圧信号に含まれているビート信号のサンプル値（つまり、量子化されたビート信号）を、演算回路２４６に出力する。 The A / D converter 245 performs A / D conversion processing (that is, quantization processing) on the beat signal output from the HPF 244. As a result, the A / D converter 245 outputs the beat signal sample value (that is, the quantized beat signal) included in the voltage signal corresponding to the scattered light received by the light receiving element 22 to the arithmetic circuit 246. To do.
　演算回路２４６は、Ａ／Ｄコンバータ２４５の出力（つまり、受光素子２２が受光した散乱光に応じた電圧信号に含まれているビート信号のサンプル値）に対して、ＦＦＴ（Fast Fourier Transform）を用いた周波数解析を行う。その結果、演算回路２４６は、血流量Ｑを算出する。 The arithmetic circuit 246 performs FFT (Fast Transform) on the output of the A / D converter 245 (that is, the sample value of the beat signal included in the voltage signal corresponding to the scattered light received by the light receiving element 22). Perform the frequency analysis used. As a result, the arithmetic circuit 246 calculates the blood flow rate Q.
　尚、演算器２４６が算出した血流量Ｑは、濃度算出装置２の外部に（或いは、濃度算出装置２が内部に備える不図示の処理ブロックに）対して適切なタイミングで出力されてもよい。 The blood flow volume Q calculated by the calculator 246 may be output to the outside of the concentration calculation device 2 (or to a processing block (not shown) included in the concentration calculation device 2) at an appropriate timing.
　（２－２）濃度算出装置の動作
　続いて、図１０を参照して、第２実施例の濃度算出装置２の動作の流れについて説明する。図１０は、第２実施例の濃度算出装置２の動作の流れを示すフローチャートである。 (2-2) Operation of Density Calculation Device Next, the flow of operation of the concentration calculation device 2 of the second embodiment will be described with reference to FIG. FIG. 10 is a flowchart showing the operation flow of the concentration calculation apparatus 2 of the second embodiment.
　図１０に示すように、レーザ素子１１は、チューブ１００に対してレーザ光ＬＢを照射する（ステップＳ１１）。尚、第２実施例におけるレーザ光ＬＢの照射の具体的態様は、第１実施例におけるレーザ光ＬＢの照射の具体的態様と同様である（図３参照）。 As shown in FIG. 10, the laser element 11 irradiates the tube 100 with the laser beam LB (step S11). The specific mode of irradiation with the laser beam LB in the second embodiment is the same as the specific mode of irradiation with the laser beam LB in the first embodiment (see FIG. 3).
　その後、第２実施例においても、第１実施例と同様に、ステップＳ１２からステップＳ１６の動作が行われる。具体的には、受光素子１２は、受光した散乱光を電気信号に変換することで得られる受光信号（つまり、散乱光の光強度に相当する信号成分（つまり、上述した光強度信号であって、相対的に低域の信号成分）を含む受光信号）を生成する（ステップＳ１２）。増幅器１３は、受光素子１２から出力される受光信号（つまり、受光素子１２が受光した散乱光に応じた受光信号）を、電圧信号に変換した上で増幅する（ステップＳ１３）。ＬＰＦ１４１は、増幅器１３の出力に含まれる信号成分のうちの低域信号成分に相当する光強度信号を取得する（ステップＳ１４）。その後、Ａ／Ｄコンバータ１４２は、ＬＰＦ１４１から出力される光強度信号に対してＡ／Ｄ変換処理（つまり、量子化処理）を行う（ステップＳ１５）。その後、演算器１４３は、Ａ／Ｄコンバータ１４２の出力（つまり受光素子１２が受光した散乱光の光強度に応じた光強度信号のサンプル値）に基づいて、血流濃度Ｎを算出する（ステップＳ１６）。 Thereafter, also in the second embodiment, the operations from step S12 to step S16 are performed as in the first embodiment. Specifically, the light receiving element 12 is a light receiving signal obtained by converting the received scattered light into an electric signal (that is, a signal component corresponding to the light intensity of the scattered light (that is, the light intensity signal described above). , A light receiving signal including a relatively low frequency signal component) is generated (step S12). The amplifier 13 converts the received light signal output from the light receiving element 12 (that is, the received light signal corresponding to the scattered light received by the light receiving element 12) into a voltage signal and then amplifies it (step S13). The LPF 141 acquires a light intensity signal corresponding to a low-frequency signal component among signal components included in the output of the amplifier 13 (step S14). Thereafter, the A / D converter 142 performs A / D conversion processing (that is, quantization processing) on the light intensity signal output from the LPF 141 (step S15). Thereafter, the calculator 143 calculates the blood flow concentration N based on the output of the A / D converter 142 (that is, the sample value of the light intensity signal corresponding to the light intensity of the scattered light received by the light receiving element 12) (step S1). S16).
　ステップＳ１２からステップＳ１６における血流濃度Ｎの算出動作に続いて若しくは相前後して又は並行して、第２実施例では、受光素子２２は、受光した散乱光を電気信号に変換することで得られる受光信号を生成する（ステップＳ２２）。その後、受光素子２２は、生成した受光信号を、増幅器２３に出力する。 In the second embodiment, the light receiving element 22 obtains the received scattered light by converting the received scattered light into an electrical signal following or in parallel with the operation of calculating the blood flow concentration N in steps S12 to S16. The received light signal is generated (step S22). Thereafter, the light receiving element 22 outputs the generated light reception signal to the amplifier 23.
　受光素子２２が受光する受光信号には、移動している散乱体である血球によって散乱された散乱光と静止している組織によって散乱された散乱光との相互干渉によって生ずるビート信号光に相当する信号成分（つまり、上述したビート信号であって、相対的に高域の信号成分）が含まれている。ここで、移動している散乱体である血球によって散乱された散乱光の周波数は、静止している組織によって散乱された散乱光の周波数と比較して、血液の流速ｖに対応したレーザドップラ作用によって変化している。従って、ビート信号光に相当する信号成分（つまり、ビート信号）は、血液の流速ｖに応じた周波数の変化を示す信号成分を含んでいる。 The light reception signal received by the light receiving element 22 corresponds to beat signal light generated by mutual interference between scattered light scattered by blood cells that are moving scatterers and scattered light scattered by a stationary tissue. The signal component (that is, the above-described beat signal and a relatively high frequency signal component) is included. Here, the frequency of the scattered light scattered by the blood cell that is the moving scatterer is compared with the frequency of the scattered light scattered by the stationary tissue, and the laser Doppler action corresponding to the blood flow velocity v. Has changed. Accordingly, the signal component corresponding to the beat signal light (that is, the beat signal) includes a signal component indicating a change in frequency according to the blood flow velocity v.
　その後、増幅器２３は、受光素子２２から出力される受光信号（つまり、受光素子２２が受光した散乱光に応じた受光信号）を、電圧信号に変換した上で増幅する（ステップＳ２３）。その後、増幅器２３は、増幅した受光信号を演算回路２４に出力する。より具体的には、増幅器２３は、増幅した受光信号を、ＨＰＦ２４４に出力する。 Thereafter, the amplifier 23 converts the received light signal output from the light receiving element 22 (that is, the received light signal corresponding to the scattered light received by the light receiving element 22) into a voltage signal and then amplifies it (step S23). Thereafter, the amplifier 23 outputs the amplified light reception signal to the arithmetic circuit 24. More specifically, the amplifier 23 outputs the amplified light reception signal to the HPF 244.
　その後、ＨＰＦ２４４は、増幅器２３から出力される受光信号に含まれる信号成分のうち、高域信号成分以外の他の周波数帯域の信号成分をカットする。その結果、ＨＰＦ２４４は、増幅器２３の出力に含まれる信号成分のうちの高域信号成分に相当するビート信号を取得する（ステップＳ２４）。その後、ＨＰＦ２４４は、取得したビート信号を、Ａ／Ｄコンバータ２４５に出力する。 Thereafter, the HPF 244 cuts signal components in frequency bands other than the high-frequency signal component among the signal components included in the light reception signal output from the amplifier 23. As a result, the HPF 244 acquires a beat signal corresponding to the high frequency signal component among the signal components included in the output of the amplifier 23 (step S24). Thereafter, the HPF 244 outputs the acquired beat signal to the A / D converter 245.
　その後、Ａ／Ｄコンバータ２４５は、ＨＰＦ２４４から出力されるビート信号に対してＡ／Ｄ変換処理（つまり、量子化処理）を行う（ステップＳ２５）。具体的には、例えば、Ａ／Ｄコンバータ２４５は、Ａ／Ｄコンバータ２４５のサンプリング周期をＴａ２とすると、周期Ｔａ２毎に、ビート信号のサンプル値（つまり、量子化されたビート信号）を出力する。その後、Ａ／Ｄコンバータ２４５は、受光素子２２が受光した散乱光の干渉成分であるビート信号のサンプル値（つまり、量子化されたビート信号）を、演算器２４６に出力する。 Thereafter, the A / D converter 245 performs A / D conversion processing (that is, quantization processing) on the beat signal output from the HPF 244 (step S25). Specifically, for example, when the sampling period of the A / D converter 245 is Ta2, the A / D converter 245 outputs a beat signal sample value (that is, a quantized beat signal) for each period Ta2. . Thereafter, the A / D converter 245 outputs a beat signal sample value (that is, a quantized beat signal), which is an interference component of scattered light received by the light receiving element 22, to the computing unit 246.
　その後、演算器２４６は、Ａ／Ｄコンバータ２４５の出力（つまり受光素子２２が受光した散乱光の干渉成分であるビート信号のサンプル値）に基づいて、血流量Ｑを算出する（ステップＳ２６）。具体的には、例えば、演算器２４６は、ビート信号のサンプル値に対してＦＦＴを行う。演算器２４６は、当該ＦＦＴを行うことで得られるパワースペクトルと周波数ベクトルとの乗算結果である１次モーメントを用いて、血流量Ｑを算出する。ＦＦＴを用いた周波数解析による血流量Ｑの算出方法については、公知の方法（例えば、特許第３３１３８４１号公報に開示された方法等）が用いられてもよいため、詳細な説明を省略する。 Thereafter, the calculator 246 calculates the blood flow rate Q based on the output of the A / D converter 245 (that is, the sample value of the beat signal that is the interference component of the scattered light received by the light receiving element 22) (step S26). Specifically, for example, the arithmetic unit 246 performs FFT on the sample value of the beat signal. The computing unit 246 calculates the blood flow rate Q using a first moment that is a multiplication result of the power spectrum and the frequency vector obtained by performing the FFT. Since a known method (for example, a method disclosed in Japanese Patent No. 3313841) may be used as a method for calculating the blood flow rate Q by frequency analysis using FFT, detailed description thereof is omitted.
　このような第２実施例の濃度検出装置２は、第１実施例の濃度検出装置１が享受することができる各種効果と同様の効果を、好適に享受することができる。加えて、第２実施例の濃度検出装置２は、レーザ光ＬＢをチューブ１００に照射することで、血流濃度Ｎのみならず、血流量Ｑをも算出することができる。 Such a concentration detection apparatus 2 of the second embodiment can preferably enjoy the same effects as the various effects that the concentration detection apparatus 1 of the first embodiment can enjoy. In addition, the concentration detection apparatus 2 according to the second embodiment can calculate not only the blood flow concentration N but also the blood flow Q by irradiating the tube 100 with the laser light LB.
　尚、血流濃度Ｎ及び血流量Ｑの双方を算出する場合には、濃度検出装置２は、血流量Ｑの算出（具体的には、レーザドップラフローメトリ法を用いた血流量Ｑの算出）を実現するためにチューブ１００に対してレーザ光ＬＢを照射することが好ましい。この場合、レーザ光ＬＢが上述した態様（図３参照）で照射されるがゆえに、レーザ光ＬＢをチューブ１００に照射することで血流濃度Ｎ及び血流量Ｑの双方が算出される場合であっても、血流濃度Ｎの算出分解能の低下が抑制される。従って、レーザ光ＬＢが上述した態様（図３参照）で照射されることで実現される血流濃度Ｎの算出分解能の低下の抑制（つまり、算出分解能の相対的な向上）は、レーザ光ＬＢをチューブ１００に照射することで血流濃度Ｎ及び血流量Ｑの双方を算出する濃度検出装置２において特に有効である。 When both the blood flow concentration N and the blood flow Q are calculated, the concentration detection device 2 calculates the blood flow Q (specifically, the blood flow Q using the laser Doppler flowmetry method). In order to realize the above, it is preferable to irradiate the tube 100 with the laser beam LB. In this case, since the laser beam LB is irradiated in the above-described manner (see FIG. 3), the blood flow concentration N and the blood flow rate Q are both calculated by irradiating the tube 100 with the laser beam LB. However, a decrease in the calculation resolution of the blood flow concentration N is suppressed. Therefore, suppression of a decrease in the calculation resolution of the blood flow concentration N (that is, a relative improvement in the calculation resolution) realized by irradiating the laser beam LB in the above-described manner (see FIG. 3) is the laser beam LB. Is particularly effective in the concentration detection apparatus 2 that calculates both the blood flow concentration N and the blood flow volume Q by irradiating the tube 100 with.
　（３）第３実施例
　続いて、図１１を参照しながら、第３実施例の濃度算出装置３について説明を進める。図１１は、第３実施例の濃度算出装置３の構成を示すブロック図である。尚、以下の説明では、第１実施例の濃度算出装置１と同一の構成及び動作については、同一の参照符号及びステップ番号を付してその詳細な説明を省略する。 (3) Third Example Next, with reference to FIG. 11, a description will be given of the concentration calculation apparatus 3 of the third example. FIG. 11 is a block diagram showing the configuration of the concentration calculation apparatus 3 of the third embodiment. In the following description, the same configuration and operation as those of the concentration calculation apparatus 1 of the first embodiment are denoted by the same reference numerals and step numbers, and detailed description thereof is omitted.
　図１１に示すように、第３実施例の濃度算出装置３は、第１実施例の濃度算出装置１と比較して、ＡＰＣ（Automatic Power Control）回路３１を更に備えているという点で異なっている。第３実施例の濃度算出装置３が備えるその他の構成要素は、第１実施例の濃度算出装置１が備えるその他の構成要素と同一であってもよい。 As shown in FIG. 11, the concentration calculation device 3 of the third embodiment is different from the concentration calculation device 1 of the first embodiment in that it further includes an APC (Automatic Power Control) circuit 31. Yes. Other components included in the concentration calculation device 3 of the third embodiment may be the same as other components included in the concentration calculation device 1 of the first embodiment.
　ＡＰＣ回路３１は、バックモニタ３１１と、増幅器３１２と、減算器３１３と、制御器３１４を備えている
　バックモニタ３１１は、レーザ素子１１から照射されるレーザ光ＬＢ（特に、レーザ素子１１の出射端面の反対側の端面から漏れ出たレーザ光ＬＢ）を受光する。バックモニタ３１１は、受光したレーザ光ＬＢを電気信号に変換することで得られる受光信号を生成する。 The APC circuit 31 includes a back monitor 311, an amplifier 312, a subtractor 313, and a controller 314. The back monitor 311 is a laser beam LB emitted from the laser element 11 (particularly, the emission end face of the laser element 11). The laser beam LB) leaking from the end surface on the opposite side of the laser beam is received. The back monitor 311 generates a light reception signal obtained by converting the received laser light LB into an electrical signal.
　増幅器３１２は、バックモニタ３１１から出力される電流信号である受光信号を、電圧信号に変換した上で増幅する。 The amplifier 312 amplifies the light reception signal, which is a current signal output from the back monitor 311, after converting it into a voltage signal.
　減算器３１３は、増幅器３１２から出力される電圧信号を所定の目標信号（具体的には、レーザ素子１１から照射されるレーザ光ＬＢの目標パワーに相当する信号）から減算する。つまり、減算器３１３は、レーザ素子１１から現在照射されているレーザ光ＬＢのパワーの、目標パワーからの誤差を算出する。減算器３１３は、当該誤差を示す誤差信号を、制御器３１４に出力する。 The subtractor 313 subtracts the voltage signal output from the amplifier 312 from a predetermined target signal (specifically, a signal corresponding to the target power of the laser beam LB emitted from the laser element 11). That is, the subtracter 313 calculates an error from the target power of the power of the laser beam LB currently emitted from the laser element 11. The subtractor 313 outputs an error signal indicating the error to the controller 314.
　制御器３１４は、減算器３１３から出力される誤差信号に対して、安定した負帰還を実行するための位相補償を行う。その後、制御器３１４は、位相補償が行われた誤差信号に基づいて、レーザ素子１１を制御する。その結果、レーザ素子１１は、位相補償が行われた誤差信号に応じた量だけパワーを変化されたレーザ光ＬＢを照射する。 The controller 314 performs phase compensation for executing stable negative feedback on the error signal output from the subtractor 313. Thereafter, the controller 314 controls the laser element 11 based on the error signal subjected to phase compensation. As a result, the laser element 11 emits the laser beam LB whose power is changed by an amount corresponding to the error signal subjected to phase compensation.
　このような第３実施例の濃度算出装置３は、第１実施例の濃度算出装置１が享受することができる各種効果と同様の効果を、好適に享受することができる。 Such a concentration calculation device 3 of the third embodiment can preferably enjoy the same effects as the various effects that the concentration calculation device 1 of the first embodiment can enjoy.
　加えて、第３実施例の濃度算出装置３によれば、ＡＰＣ回路３１は、レーザ素子１１から照射されるレーザ光ＬＢのパワーを目標パワーに追従させることができる。従って、レーザ素子１１は、安定的にレーザ光ＬＢを照射することができる。その結果、濃度算出装置３は、当該安定したレーザ光ＬＢを用いて、血流濃度Ｎをより好適に（言い換えれば、より高精度に）算出することができる。 In addition, according to the concentration calculation apparatus 3 of the third embodiment, the APC circuit 31 can cause the power of the laser beam LB emitted from the laser element 11 to follow the target power. Therefore, the laser element 11 can irradiate the laser beam LB stably. As a result, the concentration calculation device 3 can calculate the blood flow concentration N more suitably (in other words, with higher accuracy) by using the stable laser beam LB.
　尚、濃度算出装置３は、バックモニタ３１１に加えて又は代えて、レーザ素子１１から照射されたレーザ光ＬＢを、ビームスプリッタを介して受光するフロントモニタを備えていてもよい。 The concentration calculation device 3 may include a front monitor that receives the laser light LB emitted from the laser element 11 via a beam splitter in addition to or instead of the back monitor 311.
　尚、第１実施例から第３実施例で説明した各構成の一部を適宜組み合わせてもよい。この場合であっても、第１実施例から第３実施例で説明した各構成の一部を適宜組み合わせることで得られる濃度算出装置は、上述した各種効果を好適に享受することができる。 In addition, you may combine suitably a part of each structure demonstrated in 1st Example to 3rd Example. Even in this case, the concentration calculation device obtained by appropriately combining a part of the configurations described in the first to third embodiments can suitably enjoy the various effects described above.
　また、本発明は、請求の範囲及び明細書全体から読み取るこのできる発明の要旨又は思想に反しない範囲で適宜変更可能であり、そのような変更を伴う濃度算出装置及び方法もまた本発明の技術思想に含まれる。 Further, the present invention can be appropriately changed without departing from the gist or idea of the invention that can be read from the claims and the entire specification, and a concentration calculation apparatus and method involving such a change are also applicable to the technology of the present invention. Included in thought.
　１、２、３　濃度算出装置
　１１　レーザ素子
　１２、２２　受光素子
　１３、２３　増幅器
　１４１　ＬＰＦ
　２４４　ＨＰＦ
　１４２、２４５　Ａ／Ｄコンバータ
　１４３、２４６　演算器
　３１１　バックモニタ
　３１２　増幅器
　３１３　減算器
　３１４　制御器 1, 2, 3 Concentration calculator 11 Laser element 12, 22 Light receiving element 13, 23 Amplifier 141 LPF
244 HPF
142, 245 A / D converter 143, 246 arithmetic unit 311 back monitor 312 amplifier 313 subtractor 314 controller

Claims (7)

  1. 　側壁で仕切られた流路に流体が流れている管路に対してレーザ光を照射する照射手段と、
    　前記管路に照射された前記レーザ光を受光することで受光信号を取得する受光手段と、
    　前記受光信号の信号強度に基づいて、前記流体の濃度を算出する算出手段と
    　を備えており、
    　前記照射手段は、(i)前記管路内での前記レーザ光の投影面であって且つ前記流路の中心軸に沿った投影面のうち前記流路に相当する領域部分に前記レーザ光のファーフィールドパターンが形成される一方で、(ii)前記投影面のうち前記側壁に相当する領域部分に前記ファーフィールドパターンが形成されないように、前記レーザ光を照射することを特徴とする濃度算出装置。     An irradiating means for irradiating a laser beam to a pipeline in which a fluid flows in a flow path partitioned by a side wall;
    A light receiving means for acquiring a light reception signal by receiving the laser light irradiated on the pipe;
    Calculating means for calculating the concentration of the fluid based on the signal intensity of the light reception signal, and
    The irradiating means is (i) a projection surface of the laser light in the conduit and a region of the projection surface along the central axis of the flow channel where the laser light is applied to a region corresponding to the flow channel. While the far field pattern is formed, (ii) the density calculation device irradiates the laser beam so that the far field pattern is not formed in a region corresponding to the side wall of the projection surface. .
  2. 　前記照射手段は、前記投影面上において、前記ファーフィールドパターンの長軸が前記流路の中心軸が延びる方向に沿って配置されるように、前記レーザ光を照射することを特徴とする請求項１に記載の濃度算出装置。 The irradiating unit irradiates the laser light on the projection plane so that a long axis of the far field pattern is arranged along a direction in which a central axis of the flow path extends. 1. The concentration calculation apparatus according to 1.
  3. 　前記照射手段は、前記投影面上において、前記ファーフィールドパターンの長軸が前記流路の中心軸が延びる方向に対して平行に配置されるように、前記レーザ光を照射することを特徴とする請求項１に記載の濃度算出装置。 The irradiating means irradiates the laser light on the projection plane so that a long axis of the far field pattern is arranged in parallel to a direction in which a central axis of the flow path extends. The density | concentration calculation apparatus of Claim 1.
  4. 　前記照射手段は、前記投影面上において、前記ファーフィールドパターンの長軸の中心軸が前記流路の中心軸と一致するように、前記レーザ光を照射することを特徴とする請求項１に記載の濃度算出装置。 The said irradiation means irradiates the said laser beam so that the central axis of the long axis of the said far field pattern may correspond with the central axis of the said flow path on the said projection surface. Concentration calculator.
  5. 　前記管路は、当該濃度算出装置に対して着脱可能な透明状の管路であり、
    　前記流体は、前記被測定対象としての生体の外部を流れる前記生体の血流であることを特徴とする請求項１に記載の濃度算出装置。     The conduit is a transparent conduit that can be attached to and detached from the concentration calculator.
    The concentration calculation apparatus according to claim 1, wherein the fluid is a blood flow of the living body that flows outside the living body as the measurement target.
  6. 　前記照射手段から照射される前記レーザ光の一部を受光することで前記レーザ光のパワーを所望レベルに保つパワー制御手段を更に備えることを特徴とする請求項１に記載の濃度算出装置。 The concentration calculation apparatus according to claim 1, further comprising power control means for receiving a part of the laser light emitted from the irradiation means to maintain the power of the laser light at a desired level.
  7. 　側壁で仕切られた流路に流体が流れている管路に対してレーザ光を照射する照射工程と、
    　前記管路に照射された前記レーザ光を受光することで受光信号を取得する受光工程と、
    　前記受光信号の信号強度に基づいて、前記流体の濃度を算出する算出工程と
    　を備えており、
    　前記照射工程では、(i)前記レーザ光の前記管路内での投影面であって且つ前記流路の中心軸に沿った投影面のうち前記流路に相当する領域部分に前記レーザ光のファーフィールドパターンが形成される一方で、(ii)前記投影面のうち前記側壁に相当する領域部分に前記ファーフィールドパターンが形成されないように、前記レーザ光が形成されることを特徴とする濃度算出方法。     An irradiation step of irradiating laser light to a pipe line in which a fluid flows in a flow path partitioned by side walls;
    A light receiving step of acquiring a light reception signal by receiving the laser light irradiated on the pipe;
    A calculation step of calculating the concentration of the fluid based on the signal intensity of the light reception signal, and
    In the irradiation step, (i) the laser light is projected onto an area portion corresponding to the flow path in a projection plane along the central axis of the flow path and the projection plane of the laser light in the pipe. While the far field pattern is formed, (ii) the density calculation is characterized in that the laser beam is formed so that the far field pattern is not formed in a region corresponding to the side wall of the projection surface. Method.
PCT/JP2012/060968 2012-04-24 2012-04-24 Density calculation device and method WO2013161007A1 (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6337235A (en) * 1986-07-31 1988-02-17 Hitachi Electronics Eng Co Ltd Apparatus for detecting fine particle in liquid
JPS6337236A (en) * 1986-07-31 1988-02-17 Hitachi Electronics Eng Co Ltd Method for excluding stray light of apparatus for detecting fine particle in liquid
JPH11166892A (en) * 1997-12-05 1999-06-22 Shiroki Corp Liquid concentration measuring device
JP2003050200A (en) * 2001-06-01 2003-02-21 Nikkiso Co Ltd Method and apparatus for measuring optical component
JP3783991B2 (en) * 1998-05-29 2006-06-07 ホーチキ株式会社 Smoke detector
JP2010190934A (en) * 2009-02-16 2010-09-02 Fujifilm Corp Light-guide, light source apparatus and endoscope system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6337235A (en) * 1986-07-31 1988-02-17 Hitachi Electronics Eng Co Ltd Apparatus for detecting fine particle in liquid
JPS6337236A (en) * 1986-07-31 1988-02-17 Hitachi Electronics Eng Co Ltd Method for excluding stray light of apparatus for detecting fine particle in liquid
JPH11166892A (en) * 1997-12-05 1999-06-22 Shiroki Corp Liquid concentration measuring device
JP3783991B2 (en) * 1998-05-29 2006-06-07 ホーチキ株式会社 Smoke detector
JP2003050200A (en) * 2001-06-01 2003-02-21 Nikkiso Co Ltd Method and apparatus for measuring optical component
JP2010190934A (en) * 2009-02-16 2010-09-02 Fujifilm Corp Light-guide, light source apparatus and endoscope system

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