Interface detection sensor and interface detection method

Abstract

To provide an interface detection sensor that can increase a scan speed at which a light scans a detection target and can suppress a decline of a detection accuracy of an interface included in a detection target.SOLUTION: An interface detection sensor comprises: a light projecting unit for sequentially projecting a projection object light set including a first projection object light having a first wavelength and a second projection object light having a second wavelength, to a detection target having multiple layers; a light receiving unit for sequentially receiving a reception object light set including a first reception object light derived from the first projection object light through passing through the detection target, and a second reception object light derived from the second projection object light through passing through the detection target; and a control unit for synchronizing a light projecting timing of the light projecting unit and a light receiving timing of the light receiving unit, and for detecting interfaces of the multiple layers included in the detection target based on the sequentially reception object light set. The light projecting unit starts projecting the second projection object light during or at finishing the projection of the first projection object light.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to an interface detection sensor and an interface detection method.

Background Art

[0002] Conventionally, methods for detecting an interface are known. For example, two optical pulses having different wavelengths are alternately turned on with a time interval to irradiate a sample tube, the intensities of the two optical pulses that have passed through the sample tube are measured, and interface detection is detected according to the intensities of the two measured optical pulses (see Patent Document 1). Here, the two optical pulses follow essentially the same optical axis passing through the sample tube. Also, for example, a centrifuge system is known in which two radiations having different wavelengths are radiated toward a sample tube at different timings by a beam combiner, and the two transmitted radiations are detected by the same detector to detect information about the sample tube (see Patent Document 2). Here, the two radiations travel at slightly different positions, and the two transmitted radiations also travel at slightly different positions.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the prior art, it is difficult to increase the scanning speed for scanning a detection target such as blood while suppressing a decrease in the interface detection accuracy within the detection target.

[0005] The present disclosure has been made in view of the above circumstances, and provides an interface detection sensor and an interface detection method capable of suppressing a decrease in interface detection accuracy within a detection target while increasing the scanning speed for scanning the detection target.

Means for Solving the Problems

[0006] One aspect of the present disclosure includes a light projecting unit that sequentially projects a light projection light set including a first projection light having a first wavelength and a second projection light having a second wavelength onto a detection target having a plurality of layers, a first received light that is a signal obtained by the first projection light passing through the detection target, and a second received light that is a signal obtained by the second projection light passing through the detection target. A light receiving unit that sequentially receives the light receiving light set including the above, and synchronizes the light projection timing by the light projection unit and the light receiving timing by the light receiving unit, and based on the sequentially received light receiving light set, the plurality of layers included in the detection target. A control unit for detecting an interface, wherein the light projecting unit starts projecting the second projection light during or at the end of projecting the first projection light Then, the light receiving unit starts receiving the second received light during or at the end of receiving the first received light in synchronization with the projection of the projection light set by the projection unit, and the control unit controls the projection unit to project the projection light set so that the amount of received light of the received light set by the light receiving unit after the start of receiving the second received light is larger than the amount of received light of the received light by the light receiving unit before the start of receiving the second received light. It is an interface detection sensor.

[0007] One aspect of the present disclosure is An interface detection method, Projecting a first projection light having a first wavelength onto a detection target having a plurality of layers and A second projection light having a second wavelength sequentially projects a projection light set including Projecting step, a first received light that is a signal obtained by the first projection light passing through the detection target, and a second received light that is a signal obtained by the second projection light passing through the detection target. A step of receiving a light receiving light set including the above, and a step of detecting an interface of the plurality of layers included in the detection target based on the light receiving light set. sequentially Receiving step, and having The step of sequentially projecting the projection light set includes the step of starting to project the second projection light during or at the end of projecting the first projection light. The step of sequentially receiving the received light set includes the step of starting to receive the second received light during or at the end of receiving the first received light in synchronization with the projection of the projection light set. The interface detection method further includes the step of controlling the projection unit to project the projection light set so that the amount of received light of the received light set after the start of receiving the second received light is larger than the amount of received light of the received light before the start of receiving the second received light. It is an interface detection method.

Advantages of the Invention

[0008] According to the present disclosure, it is possible to suppress a decrease in interface detection accuracy within a detection target while increasing the scanning speed for scanning the detection target.

Brief Description of the Drawings

[0009]

FIG. 1

FIG. 2A

FIG. 2B

FIG. 3

FIG. 4A

FIG. 4B

FIG. 4C

FIG. 5

FIG. 6

FIG. 7

FIG. 8

FIG. 9A

FIG. 9B

FIG. 9C

FIG. 10A

FIG. 10B

FIG. 10C

FIG. 11A

FIG. 11B

FIG. 12

FIG. 13

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, a more detailed description than necessary may be omitted. For example, detailed descriptions of well - known matters and descriptions of substantially the same configurations may be omitted. This is to avoid making the following description unnecessarily redundant and to facilitate the understanding of those skilled in the art. It should be noted that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and it is not intended to limit the subject matter described in the claims thereby.

[0011] (Background Leading to the Content of the Embodiment) Conventional interface detection sensors repeatedly alternate the lighting of two types of optical pulses while changing the position of the sample tube irradiated with the optical pulses with respect to the light source that projects the optical pulses at a constant speed along the longitudinal direction of the sample tube. The repetition period (light projection period) of the lighting of the two types of optical pulses is set to be long so that the trailing waveforms (tail waveforms) due to the accumulated charges at the PN junctions of the photodiodes do not overlap and the influence on the next adjacent signal in time series is reduced.

[0012] Here, in order to shorten the time required for interface detection, it is necessary to increase the update speed (scanning speed) of the position of the sample tube with respect to the above light source. On the other hand, if the scanning speed is increased without changing the light projection period (for example, if the scanning speed is doubled), the interval between the irradiation positions (also referred to as vertical irradiation positions) where the sample tube is irradiated with optical pulses widens. In this case, since the vertical irradiation positions cannot be set finely along the longitudinal direction of the sample tube, the interface detection accuracy decreases.

[0013] On the contrary, in order to set the vertical irradiation positions finely along the longitudinal direction of the sample tube, if the light projection period is shortened (for example, if the light projection period is halved), the trailing waveform of the previous signal adjacent in time series overlaps with the next signal, causing an influence on the received waveform of the next signal. Therefore, the interface detection accuracy also decreases.

[0014] In the following embodiments, an interface detection sensor and an interface detection method will be described that can suppress a decrease in the interface detection accuracy within the detection target while increasing the scanning speed for scanning the detection target.

[0015] (Embodiment) <Configuration of Blood Interface Detection System> FIG. 1 is a diagram showing a configuration example of a blood interface detection system 5 in an embodiment. The blood interface detection system 5 includes a blood collection tube 50, a moving mechanism 60, and an interface detection sensor 100.

[0016] In addition, in the present embodiment, the x-direction, y-direction, and z-direction are defined. The z-direction is the extending direction of the blood collection tube 50, for example, the vertical direction. The y-direction is the direction perpendicular to the z-direction and is the traveling direction of the projected light projected from the light projecting unit 110 described later. The x-direction is the direction perpendicular to the y-direction and the z-direction. The positive side of the z-direction is also described as up, and the negative side of the z-direction is also described as down.

[0017] The blood collection tube 50 accommodates the blood sample C (see FIG. 3 etc.). The blood sample C is an example of a detection target at the interface. The blood sample C has a plurality of layers, for example, has a layer of the blood clot C1 and a layer of the serum C3 (see FIG. 3 etc.). The blood sample C may have a layer of the separation material C2 (see FIG. 3 etc.). The separation material C2 is, for example, an organic separation gel. For example, the separation material C2 is injected into the blood collection tube 50 and centrifuged by a centrifuge, so that the blood sample C is separated into the blood clot C1, the separation material C2, and the serum C3. The blood clot C1 has a layer of the buffy coat C12 and a layer of the red blood cells C11. The buffy coat C12 has, for example, white blood cells and platelets.

[0018] The moving mechanism 60 has a holding arm 61 that holds the blood collection tube 50 and a driving member (for example, a motor) that supplies a driving force to the holding arm 61. The moving mechanism 60 moves the blood collection tube 50 along the longitudinal direction (z-direction) of the blood collection tube 50. The longitudinal direction of the blood collection tube 50 is parallel to the vertical direction. Note that the moving direction (z-direction) of the blood collection tube 50 is the scanning direction for interface detection.

[0019] The interface detection sensor 100 includes a light projecting unit 110, a light receiving unit 120, and a control unit 130. The housing of the interface detection sensor 100 has an arbitrary shape, for example, a U-shape as shown in FIG. 1. In the U-shape, there is a space between the light projecting unit 110 and the light receiving unit 120, and the light projecting unit 110 and the light receiving unit 120 are arranged at a distance d1 apart. In the space between the light projecting unit 110 and the light receiving unit 120, the blood collection tube 50 is arranged to be movable in the z direction. The distance d1 is the distance from the light projection port of the light projecting unit 110 to the light reception port of the light receiving unit 120, and is also referred to as the light projection-reception distance. Note that the position of the blood collection tube 50 may be fixed, and the interface detection sensor 100 may be arranged to be movable in the z direction by a moving mechanism 60. Even in this case, the relative positional relationship along the z direction between the interface detection sensor 100 and the blood collection tube 50 can be changed.

[0020] When the interface detection sensor 100 has the above U-shape, the light projecting unit 110 and the light receiving unit 120 have an integrally fixed shape, so that the optical axis alignment between the light projection of the light projecting unit 110 and the light reception of the light receiving unit 120 becomes easy. Note that the interface detection sensor 100 does not necessarily have to be formed in a U-shape.

[0021] The light projecting unit 110 sequentially projects (irradiates) a light projection light set S10 including a plurality of projection lights S11, S12,... having different wavelengths λ (λ1, λ2,...) toward the blood collection tube 50. The projection light is, for example, laser light and may be pulsed light. The light receiving unit 120 sequentially receives a light reception light set S20 including a plurality of reception lights S21, S22,... having different wavelengths λ. The reception light is, for example, laser light and may be pulsed light. The reception light is a signal obtained by the projection light projected by the light projecting unit 110 passing through the blood collection tube 50. The control unit 130 non-contactly detects the boundary (interface) of each layer of the blood sample C in the blood collection tube 50 based on the light reception light set S20 received by the light receiving unit 120.

[0022] Specifically, when the separation material C2 is present in the blood sample C in the blood collection tube 50, the control unit 130 detects at least one of the interfaces between the blood clot C1 layer and the separation material C2 layer, between the separation material C2 layer and the serum C3 layer, and between the serum C3 layer and the air layer. When the separation material C2 is not present in the blood sample C in the blood collection tube 50, the control unit 130 detects at least one of the interfaces between the blood clot C1 layer and the serum C3 layer, and between the serum C3 layer and the air layer.

[0023] FIG. 2A is a block diagram showing a configuration example of the interface detection sensor 100. As described above, the interface detection sensor 100 includes a light projecting unit 110, a light receiving unit 120, and a control unit 130.

[0024] The light projecting unit 110 includes one or more (for example, two) drivers 111, one or more (for example, two) light projecting elements 112, one or more (for example, two) lenses 113, and a multiplexer 114. Note that the drivers 111, the light projecting elements 112, and the lenses 113 are provided in a plurality of systems corresponding to the number of light projection lights having different wavelengths projected by the light projecting unit 110.

[0025] Each driver 111 acquires control information from the control unit 130, drives each light projecting element 112 connected to each driver 111 based on the control information, and supplies a light projection signal. For example, the driver 111A drives the light projecting element 112A and supplies a light projection signal. The driver 111B drives the light projecting element 112B and supplies a light projection signal.

[0026] Each light projecting element 112 converts the light projection signal from the driver 111 from an electrical signal into an optical signal, and projects each light projection light having a different wavelength λ (λ1, λ2,...). For example, the light projecting element 112A projects the light projection light S11 having a wavelength λ1 (for example, 1550 nm or 1300 nm). The light projecting element 112A projects the light projection light S12 having a wavelength λ2 (for example, 980 nm).

[0027] The wavelength λ1 of the projection light S11 and the wavelength λ2 of the projection light S12 may be determined by the control unit 130 according to the detection target. The wavelength λ1 and the wavelength λ2 are determined such that the projection light S11 and the projection light S12 change between the respective layers of the detection target. The respective layers may include at least one of between the layer of the blood clot C1 and the layer of the separation material 62, between the layer of the separation material 62 and the layer of the serum C3, between the layer of the serum C3 and the layer of air, or between the layer of the blood clot C1 and the layer of the serum C3 when the separation material C2 is absent.

[0028] The projection light S11 is light having a wavelength in the infrared region. Also, the projection light S12 is light having a wavelength in a wavelength region shorter than the wavelength of the projection light S11. The projection lights S11 and S12 are preferably light having wavelengths in the near-infrared region. The wavelength λ1 is, for example, any wavelength from 1300 nm to 2000 nm. The wavelength λ2 is, for example, any wavelength from 800 nm to 1100 nm. The wavelength λ1 is, for example, 1550 nm. The wavelength λ2 is, for example, 980 nm.

[0029] Each lens 113 causes each projection light projected from each projection element 112 to travel toward the multiplexer 114. For example, the lens 113A causes the projection light S11 to travel toward the multiplexer 114, and the lens 113B causes the projection light S12 to travel toward the multiplexer 114.

[0030] The multiplexer 114 combines the respective projection lights (for example, projection lights S11 and S12) acquired via each lens 113 onto the same optical path. This same optical path is the optical path that passes through the blood collection tube 50 from the multiplexer 114 and heads toward the light receiving unit 120. The multiplexer 114 may include, for example, a reflection mirror and a dichroic mirror. The combined projection lights S11 and S12 form a projection light set S10, are emitted from the projection port to the outside of the projection unit 110, pass through the blood collection tube 50, and head toward the light receiving unit 120.

[0031] The light receiving unit 120 includes a lens 121, a light receiving element 122, and an amplifier 123. Note that the light receiving unit 120 may not include the lens 121.

[0032] The lens 121 acquires a set of received light S20 including the received lights S21 and S22 that have passed through the respective projected lights S11 and S12, via the light receiving port. The lens 121 condenses the received lights S21 and S22 onto the light receiving element 122. The light receiving element 122 converts the optical signal as the received light into an electrical signal, and outputs a received signal with a signal level corresponding to the amount of received light of the received light to the amplifier 123. The amplifier 123 amplifies each received signal output from the light receiving element 21 and outputs it to the control unit 130.

[0033] The control unit 130 includes an amplifier 131, an AD converter 132, a CPU 133, an output unit 144, and an output unit 145. Note that the control unit 130 may not include the amplifier 131.

[0034] The amplifier 131 amplifies each received signal acquired from the light receiving unit 120. The AD converter 132 converts the analog values of these received signals into digital values and sends them to the CPU 133. This digital value indicates the amount of received light of the received lights S21 and S22 included in the set of received light S20 received by the light receiving unit 120.

[0035] The CPU 133 is an example of a processor and controls the light projecting unit 110 and the light receiving unit 120. The CPU 133 synchronizes, for example, the light projection timing by the light projecting unit 110 and the light reception timing by the light receiving unit 120. The CPU 133 detects the interfaces of each layer of the inspection target (for example, the blood sample C in the blood collection tube 50) based on the amount of received light (signal level of the received signal) of the received lights S21 and S22 acquired from the AD converter 132.

[0036] For example, the CPU 133 may collect data indicating the temporal change in the amount of received light S21 and data indicating the temporal change in the amount of received light S22, and detect the interfaces of the respective layers of the blood sample C based on the collected data. For example, the CPU 133 may detect the interfaces of the respective layers of the blood sample C based on the difference between the amount of received light S21 and the amount of received light S22. For example, the CPU 133 may compare the threshold value stored in a memory (not shown) provided in the control unit 130 with the amount of received light, and detect the interface based on the result of this comparison. The threshold value is set according to the detection target. For example, in the blood sample C as the detection target, when detecting the interface between the blood clot C1 and the separation material C2, the interface between the layer of the separation material C2 and the layer of the serum C3, and the interface between the layer of the serum C3 and the air layer, threshold values for detecting the respective interfaces may be set respectively. The CPU 133 outputs, via the output unit 134, a detection signal including information on the detected interface to the outside.

[0037] The CPU 133 may previously hold in the memory characteristic information indicating the relationship between each wavelength of light and the transmittance, that is, information on the transmittance spectrum of each wavelength. FIG. 2B is a graph showing the transmission characteristics (an example of characteristic information) of each projected light with respect to the blood sample C. This transmission characteristic shows the relationship between the wavelength of each projected light and the transmittance. This transmittance indicates the ratio between the amount of received light when the projected light is directly received as received light by an arbitrary light receiving element and the amount of received light when the received light transmitted through a specimen with a thickness of 16 mm is received by the same light receiving element. The solid characteristic line A1 indicates the transmittance of the serum C3. The dashed characteristic line A2 indicates the transmittance of the separation material C2. The dashed characteristic line A3 indicates the transmittance of the blood clot C1. The CPU 133 may determine the wavelength λ1 of the projected light S11 and the wavelength λ2 of the projected light S12 projected by the projection unit 110 based on the characteristic information. The CPU 133 may include information on the wavelength λ1 of the projected light S11 and the wavelength λ2 of the projected light S12 in the control information and send it to the projection unit 110 via the output unit 135.

[0038] The CPU 133 controls the light projection by the light projection unit 110 such that the amount of received light of the received light set S20 increases in a stepped manner over time. For example, the CPU 133 may determine light projection information regarding the projection of each projected light based on the characteristic information held in the memory. The light projection information of the projected light may include, for example, at least one of the amount of light projection (signal level of the light projection signal) of each projected light, the wavelength of each projected light, and the projection order of each projected light. In this case, the CPU 133 acquires information on the transmittance of each layer of the detection target when light of each wavelength is projected as characteristic information, and calculates the attenuation amount when the projected light of each wavelength passes through each layer of the detection target based on this transmittance. Then, the CPU 133 may determine the amount of light projection of the projected light such that the amount of received light of the received light obtained by subtracting the attenuation amount from the amount of light projection of the projected light becomes stepped over time. Further, when the amount of light projection of the projected light is determined in advance, the CPU 133 may calculate the attenuation amount that gives a desired amount of received light, calculate the transmittance corresponding to the attenuation amount, and derive the wavelength that gives such transmittance from the characteristic information. The CPU 133 may include the determined light projection information in the control information and send it to the light projection unit 110 via the output unit 135.

[0039] When the amount of received light of the received light set S20 decreases in a stepped manner over time, the CPU 133 switches the projection order of the plurality of projected lights included in the projected light set S10. The CPU 133 may include the information on the switched projection order in the control information and send it to the light projection unit 110 via the output unit 135.

[0040] FIG. 3 is a diagram showing a first example of the projection timing of the projected light set S10, the reception timing of the received light set S20, and the vertical irradiation position with respect to the blood collection tube 50. The vertical irradiation position is a position along the moving direction of the blood collection tube 50 (z-direction position) and is the position where the projected light projected from the light projection unit 110 along the y-direction passes through. In FIG. 3, as the received light set S20, an example is illustrated in which the projected light set S10 is projected such that the reception timing of the received light S21 and the reception timing of the received light S22 do not overlap in time series and are adjacent.

[0041] That is, the light projecting unit 110 starts projecting the light S11 first when projecting the light set S10 according to the control by the control unit 130. Then, the light projecting unit 110 starts projecting the light S12 at the end of the projection of the light S11, and then ends the projection of the light S12. In this case, since the control unit 130 synchronizes the light projection timing and the light reception timing, the light receiving unit 120 receives the light set S20 including the received light S21 and the received light S22 in synchronization with the light projection timing of the light S11 and the light projection timing of the light S12. As a result, when receiving the light set S20, the light receiving unit 120 first starts receiving the received light S21, starts receiving the received light S22 at the end of the reception of the received light S21, and then ends the reception of the received light S22.

[0042] In FIG. 3, the light projection period T1 of the light set S10 includes a first light projection period T11 in which the light S11 is projected and a second light projection period T12 in which the light S12 is projected. In the light projection period T1, the first light projection period T11 is the first half period in time series, and the second light projection period T12 is the second half period in time series. The first light projection period T11 and the second light projection period T12 are adjacent and continuous in time series. After projecting one light set S10, the light projecting unit 110 projects the next light set S10 after a predetermined time interval TI1. Such projection of the light set S10 is repeated. Therefore, the period obtained by combining the light projection period T1 and the predetermined time interval TI1 becomes the light projection cycle TP, and the projection of the light set S10 is repeated at the light projection cycle TP. In one cycle of the light projection cycle TP, both the light S11 and the light S12 are projected once.

[0043] In addition, the light receiving period T2 of the light receiving light set S20 includes a first light receiving period T21 during which the received light S21 is received and a second light receiving period T22 during which the received light S22 is received. In the light receiving period T2, the first light receiving period T21 is the first half period in time series, and the second light receiving period T22 is the second half period in time series. The first light receiving period T21 and the second light receiving period T22 are adjacent and continuous in time series. After receiving one light receiving light set S20, the light receiving unit 120 receives the next light receiving light set S20 after a predetermined time interval TI2. Such reception of the light receiving light set S20 is repeated. Therefore, the period obtained by combining the light receiving period T2 and the predetermined time interval TI2 is the light receiving cycle TR, and the reception of the light receiving light set S20 is repeated at the light receiving cycle TR. In one cycle of the light receiving cycle TR, both the received light S21 and the received light S21 are received once.

[0044] In addition, the moving mechanism 60 is movable in the z direction with respect to the blood collection tube 50 during the interface detection operation (during the light projection operation and the light reception operation) for detecting the interface of each layer included in the blood sample C by the interface detection sensor 100. That is, while the blood collection tube 50 moves in the z direction according to the movement control by the moving mechanism 60, the light projection unit 110 projects the light projection light set S10 and the light receiving unit 120 receives the light receiving light set S20.

[0045] For example, in FIG. 3, the blood collection tube 50 is moving in the positive direction (upward) from the negative side in the z direction during the interface detection operation. The blood collection tube 50 may move at a constant speed in the z direction. When the moving speed of the blood collection tube 50 is a constant speed, the light receiving light set S20 is received at a constant light receiving cycle TR by projecting the light projection light set S10 at a constant light projection cycle TP.

[0046] In this case, for example, when the light projecting unit 110 projects the first light projection light set S10, it irradiates the light projection light S11 on the first spatial region R1 of the blood collection tube 50 during the first light projection period T11, and the light receiving unit 120 receives the light reception light S21 that has passed through the first spatial region R1 during the first light reception period T21. The first spatial region R1 is located near the lower end of the layer of the blood clot C1 located in the lowermost layer in the blood collection tube 50. Subsequently, the light projecting unit 110 irradiates the light projection light S12 on the second spatial region R2 of the blood collection tube 50 during the second light projection period T12, and the light receiving unit 120 receives the light reception light S22 that has passed through the second spatial region R2 during the second light reception period T22. The second spatial region R2 is included in the position of the layer of the blood clot C1 in the blood collection tube 50 and is spatially continuous with the first spatial region R1 above the first spatial region R1. The control unit 130 determines whether or not the interface of the blood sample C exists within the region combining the first spatial region R1 and the second spatial region R2. Each spatial region is an example of a scan region (scanning region) for inspecting the blood sample C. Also, it can be said that each spatial region is a region where the vertical irradiation positions where the blood collection tube 50 is irradiated with the light projection light are continuous.

[0047] And, during the period from the projection of the projection light S12 of the first projection light set S10 during projection to the projection of the projection light S11 of the next second projection light set S10, there is a time interval TI1 during which no projection light is projected. Therefore, during the period from the reception of the reception light S22 of the reception light set S20 during reception to the projection of the reception light S21 of the next reception light set S20, there is a time interval TI2 during which no reception light is received. These time intervals TI1 and TI2 may be determined taking into account the fall period S22a of the reception light S22 in the second reception period T22. The fall period S22a is the period from immediately after the end of the reception of the reception light S22 until the amount of reception of the reception light S22 becomes equal to or less than a predetermined amount. The predetermined amount may be a value of 0, or even if it is not a value of 0, as long as the residual signal superimposed on the reception light in the first reception period T21 of the next reception light set S20 to be received is minute and the influence on the interface detection based on the reception of the next reception light set S20 to be received can be ignored. For example, the period from the end point of the reception of the first reception light set S20 to the start point of the reception of the second reception light set S20 following the first reception light set S20 may be longer than the fall period S22a or the same length as the fall period S22a.

[0048] The light projection unit 110 repeatedly projects the projection light set S10 at a constant light projection period TP. Thus, the projection of the projection lights S11 and S12 is also repeated at the constant light projection period TP. Therefore, the light reception unit 120 repeatedly receives the reception light set S20 at a constant light reception period TR. Thus, the reception of the reception lights S21 and S22 is also repeated at the constant light reception period TR.

[0049] For example, the light projecting unit 110 projects the second light projection light set S10 following the first light projection light set S10 after the first light projection light set S10. In FIG. 3, the first spatial region R1 where the projection light S11 of the second light projection light set S10 is projected is located near the layer of the separation material C2 located near the middle in the z direction within the blood collection tube 50. The light receiving unit 120 receives the received light S21 that has passed through this first spatial region R1. Also, the second spatial region R2 where the projection light S12 of the second light projection light set S10 is projected is located spatially continuously above the first spatial region R1 and near the lower end of the serum C3 layer located above the layer of the separation material C2. The light receiving unit 120 receives the received light S22 that has passed through this second spatial region R2.

[0050] Similarly, the light projecting unit 110 projects the third light projection light set S10 following the second light projection light set S10 after the second light projection light set S10. In FIG. 3, the first spatial region R1 where the projection light S11 of the third light projection light set S10 is projected is located in the air layer located above in the z direction within the blood collection tube 50. The light receiving unit 120 receives the received light S21 that has passed through this first spatial region R1. Also, the second spatial region R2 where the projection light S12 of the third light projection light set S10 is projected is located spatially continuously above the first spatial region R1 and is located in the air layer. The light receiving unit 120 receives the received light S22 that has passed through this second spatial region R2.

[0051] The higher the moving speed of the blood collection tube 50 in the z direction by the moving mechanism 60, the wider the spatial interval of the vertically irradiated positions where the light is repeatedly projected. That is, the higher the moving speed of the blood collection tube 50 in the z direction by the moving mechanism 60, in order to obtain as many detection results for the detection target as possible, it is preferable that the distance d2 along the z direction of the vertically irradiated positions where the projection lights S11 of adjacent light projection light sets S10 are projected is shorter. On the other hand, in order to shorten the distance d2, it is necessary to shorten the projection period TP. In this case, if the projection light S11 and the projection light S12 are projected with a time interval, the received light S21 and the received light S22 are likely to be mixed.

[0052] In contrast, the interface detection sensor 100 can continuously receive the received light S21 and S22 in time series by continuously sending the projected light S11 and S12 in time series, and can easily shorten the projection period TP and the reception period TR. Therefore, the interface detection sensor 100 can project as much projected light S11 and S12 as possible in as short a time as possible, and can receive as much received light S21 and S22 as possible in as short a time as possible. Therefore, the distance d2 can be made as short as possible.

[0053] Further, the control unit 130 causes the light projecting unit 110 to project light so that the amount of received light in time series included in the received light set S20 increases in an upward step shape. That is, in each reception period T2, the characteristics (for example, the amount of projected light or the wavelength) of the projected light S11 and S12 projected by the light projecting unit 110 and the projection order of the projected light S11 and S12 are adjusted so that the amount of received light of the received light received in the second reception period T22 is larger than the amount of received light of the received light received in the first reception period T21. That is, on the reception side, the amount of received light (light energy) of the received light S21 and S22 is adjusted to increase in an upward step shape in time series.

[0054] Within the same received light set S20, the downward component of the received light S21 received earlier in time series can overlap with the received light S22 received later in time series. Even in this case, since the amount of received light in time series of the received light set S20 is in an upward step shape, the downward component of the received light S21 is sufficiently small with respect to the amount of received light of the received light S22. Therefore, the interface detection sensor 100 can suppress a decrease in the accuracy of interface detection based on the same received light set S20 including both the received light S21 and S22, in which the received light S21 received in the first reception period T21 interferes with the received light S22 received in the second reception period T22.

[0055] Further, within different received light sets S20, the received light S22 of the received light set S20 that is received first is likely to be mixed with the received light S21 of the received light set S20 that is received later. In contrast, by ensuring the time interval TI2 that takes into account the fall, the interface detection sensor 100 can interfere with the received light S21 of the later received light set S20 by the received light S22 of the previous received light set 20 in time series, and can suppress the deterioration of the interface detection accuracy based on the later received light set S20.

[0056] According to the first operation example shown in FIG. 3, the interface detection sensor 100 can acquire two adjacent received lights S21 and S22 in time series after two adjacent projected lights S11 and S12 pass through the blood collection tube 50 in time series. Then, the interface detection sensor 100 can adjust the received light amounts of the received lights S21 and S22 to increase in a rising step shape in time series. Therefore, the interface detection sensor 100 can suppress a decrease in interface detection accuracy due to the fall dullness of the received light set S20. Further, since the interface detection sensor 100 can maximize the repetition period of the light pulse irradiation, it is possible to obtain received light sets S20 corresponding to a large number of vertical irradiation positions along the z direction, and the resolution of the interface detection in the z direction can be improved.

[0057] FIGS. 4A to 4C are diagrams showing an example of the projection timing and projection amount of each of the projected lights S11 and S12 included in the projected light set S10 of the first example shown in FIG. 3.

[0058] In FIG. 4A, the projection amounts of the projected lights S11 and S12 included in each projected light set S10 increase in a rising step shape in time series. That is, the projection amount of the projected light S12 is larger than that of the projected light S11 within the same projected light set S10. In this case, the received light amounts of the received light set S20 obtained by the projected light set S10 passing through the blood sample C in the blood collection tube 50 are also likely to increase in a rising step shape in time series. For example, in the transmission characteristics with respect to the blood sample C taking into account the wavelengths λ1 and λ2 of the projected lights S11 and S12 as described above, when the transmittances of the projected lights S11 and S12 are substantially equal, the received light amounts of the received light set S20 also increase in a rising step shape on the receiving side.

[0059] In FIG. 4B, the amount of light emitted in the time series of the emitted lights S11 and S12 included in each light emission light set S10 decreases in a downward step shape. That is, the amount of light emitted by the emitted light S12 is smaller than that of the emitted light S11 within the same light emission light set S10. Even in this case, according to the transmission characteristics with respect to the blood sample C taking into account the wavelengths λ1 and λ2 of the emitted lights S11 and S12 as described above, the amount of light received by the light receiving unit 120 in the time series of the received light set S20 may increase in an upward step shape.

[0060] In FIG. 4C, the shape shown by the amount of light emitted in the time series of the emitted lights S11 and S12 included in each light emission light set S10 is rectangular. That is, the amount of light emitted by the emitted light S11 and the emitted light S12 within the same light emission light set S10 is equal. Even in this case, according to the transmission characteristics with respect to the blood sample C taking into account the wavelengths λ1 and λ2 of the emitted lights S11 and S12 as described above, the amount of light received by the light receiving unit 120 in the time series of the received light set S20 may increase in an upward step shape.

[0061] FIG. 5 is a diagram showing a second example of the light emission timing of the light emission light set S10, the light reception timing of the received light set S20, and the vertical irradiation position with respect to the blood collection tube 50. In FIG. 5, as an example of the received light set S20, the light emission light set S10 is emitted so that the light reception timing of the received light S21 and the light reception timing of the received light S22 overlap in time series.

[0062] That is, according to the control by the control unit 130, when projecting the projection light set S10, the light projecting unit 110 first starts projecting the projection light S11. Then, during the projection of the projection light S11, that is, before the projection of the projection light S11 ends, the light projecting unit 110 starts projecting the projection light S12, and then ends the projection of the projection light S12. In this case, since the control unit 130 synchronizes the projection timing and the light receiving timing, the light receiving unit 120 receives the light receiving light set S20 including the light receiving light S21 and the light receiving light S22 in synchronization with the projection timing of the projection light S11 and the projection timing of the projection light S12. As a result, when receiving the light receiving light set S20, the light receiving unit 120 first starts receiving the light receiving light S21, starts receiving the light receiving light S22 during the reception of the light receiving light S21, that is, before the reception of the light receiving light S21 ends, and then ends the projection of the light receiving light S22.

[0063] That is, when compared with the first example shown in FIG. 3, in the second example shown in FIG. 5, the projection duration of the projection light S11 that is projected earlier in time series is longer, and the projection period of the projection light S11 and the projection period of the projection light S12 at least partially overlap. Therefore, when compared with the first example shown in FIG. 3, in the second example shown in FIG. 5, the reception duration of the received light S21 that is received earlier in time series is longer, and the reception period of the received light S21 and the reception period of the received light S22 at least partially overlap.

[0064] In FIG. 5, the projection period T1 of the projection light set S10 includes a first projection period T11 during which the projection light S11 is projected and a second projection period T12 during which the projection light S11 and the projection light S12 are projected. In the projection period T1, the first projection period T11 is the first half period in time series, and the second projection period T12 is the second half period in time series. The first projection period T11 and the second projection period T12 are adjacent and continuous in time series. After projecting one projection light set S10, the light projecting unit 110 projects the next projection light set S10 after a predetermined time interval TI1. Such projection of the projection light set S10 is repeated. Therefore, the period obtained by combining the projection period T1 and the predetermined time interval TI1 becomes the projection cycle TP, and the projection of the projection light set S10 is repeated at the projection cycle TP. In one cycle of the projection cycle TP, both the projection light S11 and the projection light S12 are projected once.

[0065] Also, the light reception period T2 of the light reception light set S20 includes a first light reception period T21 during which the received light S21 is received and a second light reception period T22 during which the received light S21 and the received light S22 are received. In the light reception period T2, the first light reception period T21 is the first half period in time series, and the second light reception period T22 is the second half period in time series. The first light reception period T21 and the second light reception period T22 are adjacent and continuous in time series. After receiving one light reception light set S20, the light reception unit 120 receives the next light reception light set S20 after a predetermined time interval TI2. Such reception of the light reception light set S20 is repeated. Therefore, the period obtained by combining the light reception period T2 and the predetermined time interval TI2 becomes the light reception cycle TR, and the reception of the light reception light set S20 is repeated at the light reception cycle TR. In one cycle of the light reception cycle TR, both the received light S21 and the received light S21 are received once.

[0066] Also, the moving mechanism 60 is movable in the z direction with respect to the blood collection tube 50 during the interface detection operation (during the light projection operation and the light reception operation) for detecting the interfaces of the respective layers included in the blood sample C by the interface detection sensor 100. That is, while the blood collection tube 50 moves in the z direction according to the movement control by the moving mechanism 60, the light projection unit 110 projects the light projection light set S10 and the light reception unit 120 receives the light reception light set S20.

[0067] For example, in FIG. 5, the blood collection tube 50 is moving in the positive direction (upward) from the negative side in the z direction during the interface detection operation. The blood collection tube 50 may move at a constant speed in the z direction. When the moving speed of the blood collection tube 50 is a constant speed, by projecting the light projection light set S10 at a constant light projection cycle TP, the light reception light set S20 is received at a constant light reception cycle TR.

[0068] In this case, for example, when the light projecting unit 110 projects the first light projection light set S10, it irradiates the light projection light S11 to the first spatial region R1 of the blood collection tube 50 during the first light projection period T11. The light receiving unit 120 receives the received light S21 that has passed through the first spatial region R1 during the first light receiving period T21. The first spatial region R1 is located near the lower end of the layer of the blood clot C1 located in the lowermost layer within the blood collection tube 50. Subsequently, the light projecting unit 110 irradiates the light projection light S11 and the light projection light S12 to the second spatial region R2 of the blood collection tube 50 during the second light projection period T12. The light receiving unit 120 receives the received light S21 and the received light S22 that have passed through the second spatial region R2 during the second light receiving period T22. The second spatial region R2 is included in the position of the layer of the blood clot C1 within the blood collection tube 50 and is spatially continuous with and above the first spatial region R1. The control unit 130 determines whether or not the interface of the blood sample C exists within the region combining the first spatial region R1 and the second spatial region R2.

[0069] And, from the projection of the light projection light S12 of the first light projection light set S10 during light projection to the projection of the light projection light S11 of the next second light projection light set S10, there is a time interval TI1 during which no light projection light is projected. Therefore, from the reception of the received light S22 of the received light set S20 during light reception to the reception of the received light S21 of the next received light set S20, there is a time interval TI2 during which no received light is received. These time intervals TI1 and TI2 may be determined taking into account the decay period S22a of the received light S21 and the received light S22 during the second light receiving period T22. The decay period S22a is the period from immediately after the reception of the received light S21 and the received light S22 ends until the total received light amount of the received light S21 and the received light S22 becomes equal to or less than a predetermined amount. The predetermined amount may be the value 0, or even if it is not the value 0, as long as the residual signal superimposed on the received light during the first light receiving period T21 of the next received light set S20 to be received is minute and the influence on the interface detection based on the reception of the next received light set S20 to be received can be ignored. For example, the period from the end point of the reception of the first received light set S20 to the start point of the reception of the second received light set S20 following the first received light set S20 may be longer than the decay period S22a or the same length as the decay period S22a.

[0070] The light projecting unit 110 repeatedly projects the light projection light set S10 at a constant light projection period TP. Therefore, the light projection of the light projection lights S11 and S12 is also repeated at the constant light projection period TP. Accordingly, the light receiving unit 120 repeatedly receives the light reception light set S20 at a constant light reception period TR. Therefore, the light reception of the light reception lights S21 and S22 is also repeated at the constant light reception period TR.

[0071] For example, after the first light projection light set S10, the light projecting unit 110 projects a second light projection light set S10 that follows the first light projection light set S10. In FIG. 5, the first spatial region R1 where the light projection light S11 of the second light projection light set S10 is projected is located near the layer of the separation material C2 positioned near the middle in the z direction within the blood collection tube 50. The light receiving unit 120 receives the light reception light S21 that has passed through this first spatial region R1. Further, the second spatial region R2 where the light projection lights S11 and S12 of the second light projection light set S10 are projected is spatially continuous with the first spatial region R1 above the first spatial region R1 and is located near the lower end of the serum C3 layer positioned above the layer of the separation material C2. The light receiving unit 120 receives the light reception light S21 and the light reception light S22 that have passed through this second spatial region R2.

[0072] Similarly, after the second light projection light set S10, the light projecting unit 110 projects a third light projection light set S10 that follows the second light projection light set S10. In FIG. 5, the first spatial region R1 where the light projection light S11 of the third light projection light set S10 is projected is located in the air layer positioned above in the z direction within the blood collection tube 50. The light receiving unit 120 receives the light reception light S21 that has passed through this first spatial region R1. Further, the second spatial region R2 where the light projection light S12 of the third light projection light set S10 is projected is spatially continuous with the first spatial region R1 above the first spatial region R1 and is located in the air layer. The light receiving unit 120 receives the light reception light S21 and the light reception light S22 that have passed through this second spatial region R2.

[0073] The faster the moving mechanism 60 moves the blood collection tube 50 in the z direction, the wider the spatial interval of the vertically irradiated positions repeatedly irradiated. That is, the faster the moving mechanism 60 moves the blood collection tube 50 in the z direction, in order to obtain as many detection results for the detection target as possible, it is preferable that the distance d2 along the z direction of the vertically irradiated positions where the irradiated light S11 of the adjacent irradiated light sets S10 is irradiated is shorter. On the other hand, in order to shorten the distance d2, it is necessary to shorten the irradiation period TP. In this case, if the irradiated light S11 and the irradiated light S12 are irradiated with a time interval, the received light S21 and the received light S22 are likely to be mixed.

[0074] In contrast, the interface detection sensor 100 can receive the received light S21 and S22 in time series by irradiating the irradiated lights S11 and S12 in time series and overlapping them, and can easily shorten the irradiation period TP and the reception period TR. Therefore, the interface detection sensor 100 can irradiate as many irradiated lights S11 and S12 as possible in as short a period as possible, and can receive as many received lights S21 and S22 as possible in as short a period as possible. Therefore, the distance d2 can be made as short as possible.

[0075] Also, the control unit 130 causes the light projection unit 110 to perform light projection so that the amount of received light in the time series of the received light set S20 increases in a rising step shape. That is, in each reception period T2, the characteristics (for example, the amount of light projection or the wavelength) of the irradiated lights S11 and S12 projected by the light projection unit 110 are adjusted so that the amount of received light of the received light received in the second reception period T22 is larger than the amount of received light of the received light received in the first reception period T21. That is, on the reception side, the total (light energy) of the amount of received light (light energy) of the received light S21 in the first reception period T21 and the amounts of received light of the received light S21 and the received light S22 in the second reception period T22 is adjusted to increase in a rising step shape in time series.

[0076] Within the same received light set S20, in the second reception period T22 that is received later in time series, the received light S21 and the received light S22 are received in a superimposed manner. Here, since the received light S21 is continuously received from the first reception period T21, the characteristics of the received light S21 are known during the second reception period T22. Therefore, the control unit 130 can calculate the characteristics of the received light S22 by subtracting the characteristics of the known received light S21 from the total characteristics of the received light S21 and the received light S22. Thus, the interface detection sensor 100 can suppress a decrease in the accuracy of interface detection based on the same received light set S20 including both the received lights S21 and S22.

[0077] Also, within different received light sets S20, the received light S22 of the previously received received light set S20 is likely to be mixed in with the received light S21 of the subsequently received received light set S20. In contrast, by ensuring the time interval TI2 taking into account the downward slope, the interface detection sensor 100 can prevent the received light S22 of the previous received light set 20 in time series from interfering with the received light S21 of the subsequent received light set S20 and suppress deterioration in the accuracy of interface detection based on the subsequent received light set S20.

[0078] Furthermore, in the second reception period T22, since the received lights S21 and S22 are superimposed, the received light amount of the received light S22 in the second reception period T22 can be easily increased significantly with respect to the received light amount of the received light S21 in the first reception period T21. Thus, the interface detection sensor 100 can simplify the control of the light projection amount of the projected light by the control unit 130 and reduce the processing load of the control unit 130.

[0079] According to the second operation example shown in FIG. 5, the interface detection sensor 100 can obtain received light beams S21 and S22 that are superimposed in time series after the projected light beams S11 and S12 that are superimposed in time series pass through the blood collection tube 50. Then, the interface detection sensor 100 can adjust the received light amounts of the received light beams S21 and S22 to increase in a rising staircase shape in time series. In addition, it is possible to suppress a decrease in the interface detection accuracy due to the falling slope of the received light beam set S20. Further, since the interface detection sensor 100 can maximize the repetition period of the light pulse irradiation, it is possible to obtain a received light beam set S20 corresponding to a large number of vertical irradiation positions along the z direction, and the resolution of the interface detection in the z direction can be improved.

[0080] FIG. 6 is a diagram showing an example of the reception timing and reception amount of each of the received light beams S21 and S22 included in the received light beam set S20 of the first example shown in FIG. 3.

[0081] In FIG. 3, it was illustrated that the received amounts of the received lights S21 and S22 included in each received light set S20 are received in a fixed amount, but actually, the received amounts of the received lights S21 and S22 can change. Based on the received amounts of the received lights S21 and S22 within the received light set S20, the control unit 130 can adjust the projection order of the projection lights S11 and S12 in time series so that the received amount of the received light set S20 in time series increases in a rising staircase shape, that is, so that the received amount of the received light received in the second reception period T22 is larger than the received amount of the received light received in the first reception period T21. For example, when the received amount of the received light received in the second reception period T22 is larger than the received amount of the received light received in the first reception period T21, it is not necessary to change the projection order of the projection lights S11 and S12. This is because it is already in a rising staircase shape in the current state. For example, when the received amount of the received light received in the second reception period T22 is smaller than the received amount of the received light received in the first reception period T21, the projection order of the projection lights S11 and S12 may be swapped. Thereby, after the projection order is swapped, it is highly likely that the received amount of the received light set S20 in time series increases in a rising staircase shape, and an improvement in the interface detection accuracy can be expected. Also, for example, when the received amount of the received light received in the first reception period T21 is equal to the received amount of the received light received in the second reception period T22, it may or may not be necessary to swap the projection order of the projection lights S11 and S12.

[0082] Each time the received light set S20 is received by the light receiving unit 120, the control unit 130 can adjust the order of the projection lights S11 and S12 so that the received amount of the received light set S20 in time series increases in a rising staircase shape, that is, so that the received amount of the received light received in the second reception period T22 is larger than the received amount of the received light received in the first reception period T21. In this case, the control unit 130 may constantly monitor the light receiving state by the light receiving unit 120 in order to feedback the light receiving state by the light receiving unit 120 to the projection unit 110 every time. Then, the control unit 130 may control the projection state (for example, the projection amount of each projection light) by the projection unit 110 according to the light receiving state by the light receiving unit 120 when necessary.

[0083] In FIG. 6, in the first light reception light set S20 in time series, since the amount of received light of the received light received in the second light reception period T22 is larger than the amount of received light of the received light received in the first light reception period T21, the control unit 130 does not change the light projection order (the order of the projected lights S11, S12). As a result, in the second light reception light set S20 in time series, the received lights are received in the order of the received lights S21, S22. Also, in the second light reception light set S20 in time series, the amount of received light of the received light received in the first light reception period T21 is equal to the amount of received light of the received light received in the second light reception period T22, and the control unit 130 does not change the light projection order (the order of the projected lights S11, S12). As a result, in the third light reception light set S20 in time series, the received lights are received in the order of the received lights S21, S22. Also, in the third light reception light set S20 in time series, since the amount of received light of the received light received in the second light reception period T22 is smaller than the amount of received light of the received light received in the first light reception period T21, the control unit 130 changes the light projection order to the order of the projected lights S12, S11. As a result, in the fourth light reception light set S20 in time series, the received lights are received in the order of the received lights S22, S21. Also, in the fourth light reception light set S20 in time series, since the amount of received light of the received light received in the second light reception period T22 is larger than the amount of received light of the received light received in the first light reception period T21, the control unit 130 does not change the light projection order (the order of the projected lights S12, S11). As a result, in the fifth light reception light set S20 in time series, the received lights are received in the order of the received lights S22, S21.

[0084] FIG. 7 is a diagram showing an example of the light reception timing and the amount of received light of each of the received lights S21 and S22 included in the second example of the light reception light set S20 shown in FIG. 5.

[0085] In FIG. 5, it was exemplified that the received amounts of the received lights S21 and S22 included in each received light set S20 are received in a fixed amount. However, actually, the received amount of each received light may change. In FIG. 7, in the first received period T21 included in the received period T2 of each received light set S20, one received light S21 is received, and in the second received period T22, both the received light S21 and the received light S22 are received. Therefore, even if the received amounts of the received lights S21 and S22 change, the received amount in the second received period T22 is always larger than the received amount in the first received period T21. Therefore, the received amount of the received light set S20 in time series always increases in a rising staircase shape. Thus, the adjustment of the light projection order as described above is unnecessary.

[0086] Next, the light beam shapes of the projected lights S11 and S12 will be described.

[0087] FIG. 8 is a diagram showing an example of the vertical irradiation position with respect to the blood collection tube 50, the circular beam B1 and the rectangular beam B2 arranged at each scan position.

[0088] The light beam shape of the projected light projected by the light projection unit 110 can be a circular shape, a rectangular shape, or the like. The length l1 along the x direction perpendicular to the z direction of the circular beam B1 and the rectangular beam B2 indicates the length along the x direction of the light receiving port of the light receiving unit 120. The length l2 along the z direction of the circular beam B1 and the rectangular beam B2 indicates the length along the z direction of the light receiving port of the light receiving unit 120. Therefore, referring to FIG. 8, it can be understood that the circular beam B1 has a larger amount of light beam not received by the light receiving port than the rectangular beam B2. That is, the rectangular beam B2 has a higher light energy utilization efficiency than the circular beam B1.

[0089] FIGS. 9A, 9B, and 9C are diagrams for explaining the traveling state of the projected light on the observation surface according to the presence or absence of displacement of the blood collection tube 50 when the projected light is a circular beam.

[0090] In Fig. 9A, there is a vertical irradiation position on the layer of the separation material C2 in the blood collection tube 50, an observation surface is included, and it shows that the projection light is projected in the y direction. Also, Fig. 9B shows a view of the blood collection tube 50 held by the holding arm 61 of the moving mechanism 60 from above. In Fig. 9B, the blood collection tube 50 is arranged without displacement in the direction parallel to the xy plane, and it shows that the circular beam B1 of the projection light travels straight through the central part of the blood collection tube 50 in the x direction. Further, Fig. 9C shows a view of the blood collection tube 50 held by the holding arm 61 of the moving mechanism 60 from above. In Fig. 9C, the blood collection tube 50 is arranged with displacement in the direction parallel to the xy plane, and it shows that the circular beam B1 of the projection light is incident into the blood collection tube 50 slightly deviated from the central part of the blood collection tube 50 in the x direction, refracts in the blood collection tube 50, and exits the blood collection tube 50.

[0091] Figs. 10A, 10B, and 10C are diagrams for explaining the traveling state of the projection light on the observation surface according to the presence or absence of displacement of the blood collection tube 50 when the projection light is the rectangular beam B2.

[0092] In Fig. 10A, there is a vertical irradiation position on the layer of the separation material C2 in the blood collection tube 50, an observation surface is included, and it shows that the projection light is projected in the y direction. Also, Fig. 10B shows a view of the blood collection tube 50 held by the holding arm 61 of the moving mechanism 60 from above. In Fig. 10B, the blood collection tube 50 is arranged without displacement in the direction parallel to the xy plane, and it shows that the rectangular beam B2 of the projection light travels straight through the central part of the blood collection tube 50 in the x direction. Further, Fig. 10C shows a view of the blood collection tube 50 held by the holding arm 61 of the moving mechanism 60 from above. In Fig. 10C, the blood collection tube 50 is arranged with displacement in the direction parallel to the xy plane, and it shows that the rectangular beam B2 of the projection light is incident into the blood collection tube 50 slightly deviated from the central part of the blood collection tube 50 in the x direction. However, although the rectangular beam B2 refracts in the blood collection tube 50, it shows that most of the rectangular beam B2 exists on the optical axis of the light receiving part 120 and exits the blood collection tube 50.

[0093] Therefore, in FIG. 10C, compared with the case of the circular beam B1 in FIG. 9C, even if a positional deviation of the blood collection tube 50 occurs in the xy plane, most of the rectangular beam B2 exists on the optical axis OC of the light receiving unit 120. Thus, the interface detection sensor 100 can receive most of the received light as the rectangular beam B2 by the light receiving unit 120, and can suppress a decrease in the interface detection accuracy.

[0094] FIG. 11A is a diagram showing an example of the amount of received light of the received light corresponding to the projected light when the projected light is the circular beam B1.

[0095] Since the circular beam B1 has the same length in the x direction and the z direction, if the length in the x direction is increased according to the width of the blood collection tube 50, the length in the z direction also increases. In this case, it is likely to be affected by the state of each layer in the blood sample C in a wide range in the z direction. For example, even when actually desiring to detect the components of the layer of serum C3, the received light that has passed through the layer of the separation material C2 and the layer of air existing above and below the serum C3 can be obtained. Therefore, the amount of received light near the interface of each layer in the blood sample C tends to change smoothly.

[0096] FIG. 11B is a diagram showing an example of the amount of received light of the received light corresponding to the projected light when the projected light is the rectangular beam B2.

[0097] The rectangular beam B2 can have a shorter length in the z direction than in the x direction. In FIG. 11B, while increasing the length in the x direction according to the width of the blood collection tube 50, the length in the z direction is made shorter than the x direction. In this case, the interface detection sensor 100 can suppress being affected by the state of each layer in the blood sample C in a wide range in the z direction. Therefore, the amount of received light of the received light that has passed through near the interface of each layer in the blood sample C tends to change sharply. Thus, the interface detection sensor 100 can improve the interface detection accuracy based on the amount of received light of the received light.

[0098] Note that the length in the x direction of the circular beam B1 and the rectangular beam B2 is preferably shorter than the width of the blood collection tube 50. This is to avoid a decrease in the accuracy of interface detection by receiving light that does not pass through the blood collection tube 50.

[0099] Note that the transmittance of the projected light S11 with wavelength λ1 and the projected light S12 with wavelength λ2 are both low with respect to the blood clot C1. Also, the transmittance of the projected light S11 with wavelength λ1 is low with respect to the serum C3, and the transmittance of the projected light S12 with wavelength λ2 is high with respect to the serum C3. Further, the transmittance of the projected light S11 with wavelength λ1 and the projected light S12 with wavelength λ2 are both high with respect to the separation material C2. Also, the transmittance of the projected light S11 with wavelength λ1 and the projected light S12 with wavelength λ2 with respect to air is even higher than the transmittance with respect to the separation material C2. Therefore, by projecting the projected light S11 first and then the projected light S12 in time series, the amount of received light in the time series of the received light set S20 is likely to increase in a rising staircase shape.

[0100] The received light set S20 received by the light receiving unit 120 includes both the received light S21 and the received light S22 that have passed through the blood sample C. Thus, when the amounts of received light of the received light set S20 are arranged in ascending order, they are in the order of the blood clot C1, the serum C3, the separation material C2, and air.

[0101] In this way, since the length of the projected light beam shape in the z direction is shorter than the length of the beam shape in the x direction, the interface detection sensor 100 can improve the measurability of data and the stability of data measurement at each vertical irradiation position for interface detection. The interface detection sensor 100 can shorten the scan (detection) interval in the z direction and improve the detection resolution. Therefore, the sensitivity to changes in the z direction can be increased. Also, by ensuring the length of the beam shape in the x direction, the received light that has passed through the blood sample C in the blood collection tube 50 can be widely acquired, and even if the blood collection tube 50 is slightly displaced, light is likely to be included on the optical axis OC, so the measurement stability is improved. Note that when the length of the beam shape in the z direction is shorter than the length of the beam shape in the x direction, the beam shape is not limited to a rectangular shape and may include other shapes (for example, an elliptical shape).

[0102] Next, the effects of temporal adjacency and spatial adjacency in the present embodiment will be described.

[0103] FIG. 12 is a diagram for explaining the effect of temporal adjacency of a plurality of received lights S21 and S22 in the received light set S20.

[0104] In FIG. 12, as a comparative example, there is shown a case where two received lights S21X and S22X of two different wavelengths are obtained alternately in isolation in time series, and as an embodiment of the present invention, a case where two received lights S21 and S22 of two different wavelengths λ1 and λ2 are obtained alternately adjacent to each other in time series. It is assumed that the reception period is the same between the case of being isolated in the time series of FIG. 12 and the case of being adjacent in the time series. Also, it is assumed that the sampling interval SI for extracting two received lights for detecting the interface is an interval about half of the reception period. Further, it is assumed that the blood collection tube 50 is continuously moved at a constant speed in the z direction by the moving mechanism 60.

[0105] In this case, as shown in FIG. 12, in the case of being isolated in time series as in the comparative example, only one received light of one of the two different wavelengths is included inside one sampling interval SI. On the other hand, in the case of being adjacent in time series as in the embodiment, both two received lights S21 and S22 (received light set S20) of two different wavelengths are included inside one sampling interval SI.

[0106] Therefore, in the comparative example, since the interface is detected based on the received light amount of one received light included in the spatial region corresponding to the spatial sampling interval in the blood sample C, the detection accuracy of the interface in this spatial region becomes insufficient. On the contrary, the interface detection sensor 100 of the present embodiment can detect the interface in this spatial region with high accuracy by detecting the interface based on the received lights of two received lights included in the spatial region corresponding to the spatial sampling interval in the blood sample C.

[0107] Further, the layer of the blood clot C1 includes a layer of the buffy coat C12 containing white blood cells and platelets, and a layer containing red blood cells C11. The length of the buffy coat C12 layer in the z direction is extremely shorter than the length of the red blood cells C11 layer in the z direction, and it is a spatial region with an extremely thin thickness in the z direction. Even when such a buffy coat C12 is included in a spatial region corresponding to the spatial sampling interval in the blood sample C, the interface detection sensor 100 of the present embodiment can detect the interface of the buffy coat C12 layer with high accuracy. Thus, the interface detection sensor 100 can perform high-precision measurement of the amount of transmitted light (received light amount) in a minute region with a short length in the z direction using two received lights S21 and S22 having two different wavelengths λ1 and λ2.

[0108] FIG. 13 is a diagram for explaining the effect of spatial adjacency of scan regions arranged in the z direction of the blood sample C. In FIG. 13, with the light projection period TP by the light projection unit 110 being constant (for example, the upper limit, the shortest), patterns of vertical irradiation positions (spatial regions) for irradiating two light projection lights in the z direction are illustrated in a plurality of examples when the moving speed (scan speed) of the blood collection tube 50 in the z direction is V1, V2, and V3. Here, they are in the order of V3, V2, and V1 from high speed (that is, V3 > V2 > V1).

[0109] In FIG. 13, as a comparative example, two vertically irradiated positions that are spatially isolated are shown. Also, as the present embodiment, two vertically irradiated positions that are spatially adjacent are shown. For interface detection, two received lights with different wavelengths are required.

[0110] In FIG. 13, when the vertically irradiated positions are spatially isolated, the length in the z direction required to obtain two received lights with different wavelengths becomes longer, and the spatial region to be the target of interface detection based on these two received lights becomes wide. Or, if waiting until received lights with different wavelengths are obtained at the same vertically irradiated position and attempting to perform interface detection using a pair of two received lights obtained at the same vertically irradiated position, the time required for interface detection becomes long. Further, when it is as fast as the scan speed V3, it may not be possible to obtain a pair of received lights with different wavelengths at the same vertically irradiated position.

[0111] On the other hand, when the spatially vertical irradiation positions are adjacent, the length in the z direction required to obtain two received lights with different wavelengths becomes shorter, and the spatial region to be the target of interface detection based on these two received lights becomes a narrow range. Therefore, the accuracy of interface detection is higher when the spatially vertical irradiation positions are adjacent as in the present embodiment than when they are isolated spatially. Further, since the interface detection sensor 100 can obtain the received lights S21 and S22 received at two adjacent vertical irradiation positions regardless of the scan speed, even if the moving speed of the blood collection tube 50 in the z direction is increased, it is possible to suppress a decrease in the interface detection accuracy and improve the selectivity of the scan speed.

[0112] As described above, according to the interface detection sensor 100 of the present embodiment, an interface such as the lower surface or the upper surface of the blood clot C1 or the serum C3 in the blood sample C can be detected. And the interface detection sensor 100 can easily acquire the amount of serum, for example, based on the interfaces of the lower surface and the upper surface of the detected serum C3. Further, the interface detection sensor 100 can achieve an improvement in tact time (for example, the time required for interface detection of the entire detection target) and an improvement in interface detection accuracy. Further, the interface detection sensor 100 can maintain or increase the number of vertical irradiation positions per unit length in the z direction, that is, the number of light pulses per unit length in the z direction. Therefore, even when the scan speed of the blood collection tube 50 that houses the detection target is increased to improve the tact time, the interface detection accuracy can be maintained or improved. Further, an increase in the total amount (total power, average power) of light irradiated per unit time is suppressed, and the interface can be detected efficiently.

[0113] Further, the interface detection sensor 100 can suppress the widening of the interval between the irradiated light pulses even when the scanning speed of the blood collection tube 50 is increased by continuously projecting two projection lights S11 and S12 as the projection light set S10, and can suppress the decrease in the temporal and spatial consistency of the two projection lights S11 and S12. Therefore, the interface detection sensor 100 can suppress the failure to obtain detection data of a minute layer (for example, a buffy coat (about 1 mm thick), a meniscus (about 2 mm thick)) or the decrease in the accuracy of interface determination of a minute layer.

[0114] As described above, various embodiments have been described with reference to the drawings. Needless to say, the present invention is not limited to such examples. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope described in the claims, and it is naturally understood that they also belong to the technical scope of the present invention. Also, within the scope not departing from the gist of the invention, the components in the above embodiments may be arbitrarily combined.

[0115] In the above embodiment, the blood collection tube 50 is exemplified as moving in the direction from the negative side to the positive side (upward direction) in the z direction during the interface detection operation of the blood sample C accommodated in the blood collection tube 50, but it may move in the reverse direction (downward direction).

[0116] In the above embodiment, in FIGS. 3, 4A to 4C, and 5, the light projecting unit 110 is exemplified as first projecting the projection light having the wavelength λ1 in time series as the basic projection operation and then projecting the projection light having the wavelength λ2 in time series, but it is not limited thereto. As the basic projection operation, the light projecting unit 110 may project the projection light having the wavelength λ2 in time series first and then project the projection light having the wavelength λ1 in time series.

[0117] In the above-described embodiment, an example was given in which the relative positional relationship along the z-direction between the interface detection sensor 100 and the blood collection tube 50 can be changed, but the present invention is not limited to this. For example, the interface detection sensor 100 may be a long one that covers the length of the blood collection tube 50, and may constitute a so-called multi-axis photoelectric sensor including a plurality of light-emitting elements in the z-direction and light-receiving elements corresponding to the plurality of light-emitting elements. Even if the relative positional relationship along the z-direction between the interface detection sensor 100 (for example, the light-emitting unit 110 or the light-receiving unit 120) and the blood collection tube 50 is unchanged, the control unit 130 may sequentially change the irradiation position of the light-emitting light to the blood collection tube 50 by sequentially changing the light-emitting direction of the light-emitting light emitted from the light-emitting unit 110.

[0118] In the above-described embodiment, the processor such as a CPU may be physically configured in any manner. Also, if a programmable processor is used, the processing content can be changed by changing the program, so the degree of freedom in the design of the processor can be increased. The processor may be composed of one semiconductor chip, or may be physically composed of a plurality of semiconductor chips. When composed of a plurality of semiconductor chips, each control of the above-described embodiment may be realized by a separate semiconductor chip. In this case, it can be considered that one processor is constituted by these plurality of semiconductor chips. Also, the processor may be composed of a member (such as a capacitor) having a function different from that of the semiconductor chip. Also, one semiconductor chip may be configured to realize the functions of the processor and other functions. Also, a plurality of processors may be configured as one processor.

[0119] As described above, the interface detection sensor 100 of the above embodiment includes a light projecting unit 110, a light receiving unit 120, and a control unit 130. The light projecting unit 110 sequentially projects a light projection set S10 including a light projection light S11 (an example of a first light projection light) having a wavelength λ1 (an example of a first wavelength) and a light projection light S12 (an example of a second light projection light) having a wavelength λ2 (an example of a second wavelength) onto a blood sample C (an example of a detection target) having a plurality of layers. The light receiving unit 120 sequentially receives a light reception set S20 including a light reception light S21 (an example of a first light reception light) that is a signal obtained by the light projection light S11 passing through the detection target and a light reception light S22 (an example of a second light reception light) that is a signal obtained by the light projection light S12 passing through the detection target. The control unit 130 synchronizes the light projection timing by the light projecting unit 110 and the light reception timing by the light receiving unit 120, and detects the interfaces of a plurality of layers (for example, each layer of a blood clot C1, a separation material C2, and a serum C3) included in the detection target based on the sequentially received light reception set S20. The light projecting unit 110 starts the projection of the light projection light S12 during the projection of the light projection light S11 or at the end of the projection of the light projection light S11.

[0120] As a result, since the light reception periods of the received light S21 and the received light S22 are temporally continuous, the detection regions of the detection target by the received light S21 and the received light S22 become spatially continuous regions. Therefore, even if the detection region by the received light set S20 has a minute length along the scanning direction (for example, the z direction), the interface detection accuracy in this detection region can be maintained by the interface detection sensor 100. Further, since the detection regions by the received light S21 and the received light S22 become spatially continuous regions, the interface can be detected based on the two received lights S21 and S22 with respect to the detection region by the received light set S20 without depending on the scanning speed. Therefore, the interface detection sensor 100 can achieve a higher scanning speed. In this way, the interface detection sensor 100 can suppress a decrease in the interface detection accuracy within the detection target while increasing the scanning speed for scanning the detection target. Also, since the light projection timings of the projected light S11 and the projected light S12 do not completely match, the light reception timings of the received light S21 and the received light S21 do not completely match. Therefore, the interface detection sensor 100 can obtain the characteristics of the unknown received light by, for example, subtracting the known received light characteristics from the characteristics of the received light set S20 including each received light, and can identify the respective received lights S21 and S22.

[0121] Further, the light receiving unit 120 may start receiving the received light S22 during or at the end of receiving the received light S21 in synchronization with the projection of the projected light set S10 by the light projecting unit 110. The control unit 130 may cause the light projecting unit 110 to project the projected light set S10 such that the amount of received light by the light receiving unit 120 after the start of receiving the received light S22 is larger than the amount of received light by the light receiving unit 120 before the start of receiving the received light S22 among the amount of received light of the received light set S20.

[0122] As a result, the amount of received light in the second light reception period T22, which is the period after the start of reception of the received light S22, becomes larger than the amount of received light in the first light reception period T21, which is the period before the start of reception of the received light S22. That is, the amount of received light of the received light set S20 increases in a rising staircase shape over time. Further, since the received light S21 and the received light S22 are received continuously, the fall of the received light S21 received in the first light reception period T21 may remain in the second light reception period T22. Even in this case, due to the fact that the amount of received light increases in a rising staircase shape, the falling component of the remaining received light S21 is sufficiently small with respect to the amount of received light in the second light reception period T22. Therefore, the interface detection sensor 100 can suppress a decrease in the accuracy of interface detection based on the same received light set S20 including both received lights, in which the received light received in the first light reception period T21 interferes with the received light received in the second light reception period T22. Further, by subtracting the characteristics of the known received light S21 from the characteristics of the received light set S20, the characteristics of the unknown received light S22 may be obtained, and even if a decrease in the interface detection accuracy is suppressed.

[0123] Further, the light receiving unit 120 may receive a second received light set S20 following the first received light set S20. The first period from the end point of reception of the first received light set S20 to the start point of reception of the second received light set may be longer than or the same length as the fall period S22a required for the fall of the amount of received light at the end point of reception of the first received light set S20.

[0124] As a result, even if the fall of the received light (at least the received light S22) received in the second light reception period T22 remains after the second light reception period T22, the interface detection sensor 100 can secure a time interval TI2 until the next received light set S20 is received, thereby suppressing a decrease in the interface detection accuracy based on the subsequent received light set S20. Note that the fall of the received light received in the second light reception period T22 corresponds to the fall of the amount of received light at the end point of reception of the received light set S20.

[0125] Further, the light projecting unit 110 may determine the light projection amount of the light projection light S11 and the light projection amount of the light projection light S12 based on the transmittance of the light projection light S11 with respect to the detection target and the transmittance of the light projection light S12 with respect to the detection target.

[0126] Thereby, the interface detection sensor 100 can adjust the light projection amounts of the respective light projection lights to various light projection amounts in consideration of the transmittance of each light projection light. For example, the higher the transmittance of the light projection light with respect to the detection target, the easier it is for the light projection light to pass through the detection target and the more difficult it is to attenuate. Therefore, the light projection amount of the light projection light can be determined to be small. On the other hand, the lower the transmittance with respect to the detection target, the more difficult it is for the light projection light to pass through the detection target and the easier it is to attenuate. Therefore, the light projection amount of the light projection light can be determined to be large. Even in this case, the interface detection sensor 100 can suppress a decrease in the interface detection accuracy by the received light amount of the received light set S20 increasing in a rising staircase shape over time.

[0127] Further, the control unit 130 may compare a first received light amount, which is the received light amount of the received light by the light receiving unit 120 before the start of reception of the received light S22 included in the received light amount of the received light set S20, and a second received light amount, which is the received light amount of the received light by the light receiving unit 120 after the start of reception of the received light S22. When the first received light amount is larger than the second received light amount, the control unit 130 may instruct the light projecting unit 110 to switch the light projection order of the light projection light S11 and the light projection light S12.

[0128] As a result, the interface detection sensor 100 can feedback to the light projecting unit 110 such that the received light amounts of the received light set S20 increase in a stepwise manner over time according to the received light amount of the received light during the actual first light receiving period T21 and the received light amount of the received light during the second light receiving period T22. Therefore, the interface detection sensor 100 can adjust the light projection order of each projected light by the light projecting unit 110 to be in the above-described stepwise manner on the light receiving side without having to grasp the characteristics of each projected light in advance. Further, even when the characteristics of each projected light are grasped in advance and the light projection order of each projected light is adjusted, the magnitudes of the received light amounts of the received lights may be reversed unintentionally depending on the detection environment of the detection target. Even in this case, the interface detection sensor 100 can adjust the light projection order of each projected light by the light projecting unit 110 to be in the above-described stepwise manner on the light receiving side according to the actual received light amount of each received light.

[0129] Further, the detection target may be accommodated in a blood collection tube 50 (an example of a container) and extend along a first direction (for example, the z direction, the vertical direction). The position of the detection target with respect to the light projecting unit 110 may be movable along the first direction. The light projecting unit 110 may sequentially project the projected light set S10 in a direction perpendicular to the first direction (for example, the y direction) with respect to consecutive positions (for example, vertical irradiation positions) of the detection target along the first direction.

[0130] As a result, the interface detection sensor 100 can detect the received light amounts of a plurality of received lights S21, S22 having different wavelengths at consecutive positions of the detection target along the first direction, and can detect the interface according to the detected received light amounts. Therefore, the interface detection sensor 100 can detect the interface in a spatially continuous narrow region.

[0131] Further, the lengths of the projected light S11 and the projected light S12 projected by the light projecting unit 110 in a direction parallel to the first direction are shorter than the length in a direction perpendicular to the first direction and perpendicular to the traveling direction (for example, the y direction) of the projected light S11 and the projected light S12 (for example, the x direction).

[0132] When the lengths of the beams of the projection lights S11 and S12 in the z - direction and the x - direction are the same (for example, the beam shape is circular or square), if an attempt is made to narrow the detection interval in the z - direction to improve the interface detection accuracy, the lengths of the beams of the projection lights in the z - direction and the x - direction will become shorter. Therefore, for example, when the detection target is displaced in the x - direction due to an axial displacement occurring in the blood collection tube 50 in which the detection target is accommodated, there is a high possibility that the received lights S21 and S22 will not be received by the light - receiving unit 120. As a result, the stability of the reception of the received lights S21 and S22 decreases, and the interface detection accuracy may decrease. In contrast, the interface detection sensor 100 can narrow the spatial detection interval and improve the interface detection accuracy by making the length of the beam of each projection light S11 and S12 in the z - direction shorter than that in the x - direction, and can maintain the stability of the reception of the received light even when a displacement in the x - direction of the detection target occurs. In this way, the utilization efficiency of the light energy of the beam of the projection light can be increased.

[0133] Also, the detection target may be the blood sample C. The plurality of layers may include a layer of serum C3 and a layer of blood clot C1.

[0134] In the serum C3 and the blood clot C1 in the blood sample C, the transmittances at the wavelengths λ1 and λ2 are different. The interface detection sensor 100 can utilize this difference in transmittance to detect, for example, the interface between the layer of serum C3 and the layer of blood clot C1 in the blood sample C and the interface with other layers. (Item 1) a projection unit that sequentially projects a projection light set including a first projection light having a first wavelength and a second projection light having a second wavelength onto a detection target having a plurality of layers; a light receiving unit that sequentially receives a received light set including a first received light that is a signal transmitted through the detection target by the first projection light and a second received light that is a signal transmitted through the detection target by the second projection light; a control unit that synchronizes the projection timing by the projection unit and the reception timing by the light receiving unit, and detects an interface of the plurality of layers included in the detection target based on the received light set received sequentially; comprising the projection unit starts to project the second projection light during or at the end of projecting the first projection light; an interface detection sensor. (Item 2) the light receiving unit starts receiving the second received light during or at the end of receiving the first received light in synchronization with the projection of the projection light set by the projection unit, The control unit causes the light projecting unit to project the light projection light set so that, among the light reception amounts of the light reception light set, the light reception amount of the light received by the light receiving unit after the start of reception of the second light reception light is larger than the light reception amount of the light received by the light receiving unit before the start of reception of the second light reception light. The interface detection sensor according to item 1. (Item 3) The light receiving unit receives a second light reception light set following the first light reception light set. The first period from the end point of reception of the first light reception light set to the start point of reception of the second light reception light set is longer than or the same length as the fall period required for the fall of the light reception amount at the end point of reception of the first light reception light set. The interface detection sensor according to item 2. (Item 4) The light projecting unit determines the light projection amount of the first light projection light and the light projection amount of the second light projection light based on the transmittance of the first light projection light with respect to the detection target and the transmittance of the second light projection light with respect to the detection target. The interface detection sensor according to item 2 or 3. (Item 5) The control unit compares a first light reception amount, which is the light reception amount of the light received by the light receiving unit before the start of reception of the second light reception light and is included in the light reception amount of the light reception light set, with a second light reception amount, which is the light reception amount of the light received by the light receiving unit after the start of reception of the second light reception light. When the first light reception amount is larger than the second light reception amount, the control unit instructs the light projecting unit to swap the light projection order of the first light projection light and the second light projection light. The interface detection sensor according to any one of items 2 to 4. (Item 6) The detection target is accommodated in a container and extends along a first direction. The position of the detection target with respect to the light projecting unit is movable along the first direction. The light projecting unit sequentially projects the light projection light set in a direction perpendicular to the first direction with respect to consecutive positions of the detection target along the first direction. The interface detection sensor according to any one of items 1 to 5. (Item 7) The lengths of the first light projection light and the second light projection light projected by the light projecting unit in a direction parallel to the first direction are shorter than the length in a direction perpendicular to the first direction and perpendicular to the traveling directions of the first light projection light and the second light projection light. The interface detection sensor according to item 6. (Item 8) The detection target is a blood sample. The plurality of layers include a serum layer and a blood clot layer. The interface detection sensor according to any one of items 1 to 7. (Item 9) A step of projecting first projection light having a first wavelength onto a detection target having a plurality of layers; A step of projecting second projection light having a second wavelength by starting the projection of the second projection light during or at the end of the projection of the first projection light onto the detection target; A step of receiving a set of received light including first received light that is a signal transmitted through the detection target by the first projection light and second received light that is a signal transmitted through the detection target by the second projection light; A step of detecting an interface of the plurality of layers included in the detection target based on the set of received light; An interface detection method having the above steps.

Industrial Applicability

[0135] The present disclosure is useful for an interface detection sensor, an interface detection method, etc. that can suppress a decrease in interface detection accuracy within a detection target while increasing the scanning speed for scanning the detection target.

Description of Reference Numerals

[0136] 5 Blood interface detection system 50 Blood collection tube 60 Moving mechanism 61 Holding Arm 100 Interface Detection Sensor 110 Light Projection Unit 111 Driver 112 Light Projection Element 113 Lens 114 Combiner 120 Light Reception Unit 121 Lens 122 Light Reception Element 123 Amplifier 130 Control Unit 131 Amplifier 132 AD Converter 133 CPU 134, 135 Output Unit B1 Circular Beam B2 Rectangular Beam C Blood Sample C1 Blood Clot C11 Red Blood Cells C12 Buffy Coat C2 Separation Material C3 Serum S10 Light Projection Light Set S11, S12 Light Projection Light S20 Light Reception Light Set S21, S22 Light Reception Light

Claims

1. A light projecting unit that sequentially projects a light projection light set including a first projection light having a first wavelength and a second projection light having a second wavelength onto a detection target having a plurality of layers; A light receiving unit that sequentially receives a light reception light set including a first received light that is a signal obtained by the first projection light passing through the detection target and a second received light that is a signal obtained by the second projection light passing through the detection target; A control unit that synchronizes the light projection timing by the light projection unit and the light reception timing by the light reception unit, and detects an interface of the plurality of layers included in the detection target based on the sequentially received light reception light set; comprising The light projecting unit starts projecting the second projection light during or at the end of the projection of the first projection light, The light receiving unit starts receiving the second received light during or at the end of the reception of the first received light in synchronization with the projection of the light projection light set by the light projection unit, The control unit causes the light projecting unit to project the light projection light set such that the amount of light received by the light receiving unit after the start of reception of the second received light is larger than the amount of light received by the light receiving unit before the start of reception of the second received light among the amounts of light received by the light receiving unit of the light reception light set. An interface detection sensor.

2. The light receiving unit receives a second light reception light set following the first light reception light set, A first period from the end of reception of the first light reception light set to the start of reception of the second light reception light set is longer than or the same length as a fall period required for the amount of received light at the end of reception of the first light reception light set to fall. The interface detection sensor according to claim 1.

3. The light projecting unit determines the amount of light projection of the first projection light and the amount of light projection of the second projection light based on the transmittance of the first projection light with respect to the detection target and the transmittance of the second projection light with respect to the detection target. The interface detection sensor according to claim 1 or 2.

4. The control unit compares a first light reception amount, which is the light reception amount of the light received by the light receiving unit before the start of reception of the second received light included in the light reception amount of the received light set, with a second light reception amount, which is the light reception amount of the light received by the light receiving unit after the start of reception of the second received light, and when the first light reception amount is greater than the second light reception amount, instructs the light projecting unit to swap the light projection order of the first projected light and the second projected light. The interface detection sensor according to claim 1.

5. The detection target is accommodated in a container and extends along a first direction, the position of the detection target with respect to the light projecting unit is movable along the first direction, the light projecting unit sequentially projects the light projection light set in a direction perpendicular to the first direction with respect to consecutive positions of the detection target along the first direction. The interface detection sensor according to claim 1.

6. The lengths of the first projected light and the second projected light projected by the light projecting unit in a direction parallel to the first direction are shorter than the length in a direction perpendicular to the first direction and perpendicular to the traveling directions of the first projected light and the second projected light. The interface detection sensor according to claim 5.

7. The detection target is a blood sample, and the plurality of layers include a serum layer and a blood clot layer. The interface detection sensor according to claim 1.

8. An interface detection method, comprising: sequentially projecting a light projection light set including a first projected light having a first wavelength and a second projected light having a second wavelength onto a detection target having a plurality of layers; A step of sequentially receiving a set of received light including first received light which is a signal obtained by the first projected light passing through the detection target and second received light which is a signal obtained by the second projected light passing through the detection target; A step of detecting an interface of the plurality of layers included in the detection target based on the set of received light; It has: The step of sequentially projecting the set of projected light: Includes a step of starting projection of the second projected light during or at the end of projection of the first projected light; The step of sequentially receiving the set of received light: Includes a step of starting reception of the second received light during or at the end of reception of the first received light in synchronization with projection of the set of projected light; The interface detection method further includes: A step of projecting the set of projected light such that, among the received light amounts of the set of received light, the received light amount of the received light after the start of reception of the second received light is larger than the received light amount of the received light before the start of reception of the second received light; Interface detection method.

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