Biological fluid information acquisition device

Abstract

The invention relates to a biological fluid information acquisition device. Provided is a biological fluid information acquisition device that can be reduced in size and has high detection accuracy. A biological fluid information acquisition device is provided with a light source, a prism, a first light receiving element, a second light receiving element, a differential circuit, and a signal processing unit, and is characterized in that the prism has: a first boundary surface that branches laser light emitted from the light source into a first light beam and a second light beam; a second boundary surface for totally reflecting the second light beam; a third boundary surface that totally reflects the second light beam reflected by the second boundary surface; and a fourth boundary surface from which the second light beam reflected by the third boundary surface is emitted, where X-direction is the width direction of the biological fluid information acquisition device, and Y-direction is the thickness direction of the biological fluid information acquisition device, which is orthogonal to the X-direction, the X-direction is the width direction of the biological fluid information acquisition device, and the Y-direction is the thickness direction of the biological fluid information acquisition device. The interval between the second boundary surface and the third boundary surface in the Y direction is shorter than the interval between the first boundary surface and the fourth boundary surface in the X direction.

Description

Technical Field

[0001] The present invention relates to a biological fluid information acquisition device. Background Art

[0002] Conventionally, there is known a biological information acquisition device (see, for example, Patent Document 1) that uses scattered light from biological tissue to acquire biological fluid information such as blood flow, blood volume, blood flow velocity, and pulse in the biological tissue.

[0003] The biological information acquisition device described in Patent Document 1 comprises: a light source that emits laser light; a light branching element that branches the laser light into a first light beam and a second light beam; a first light receiving element that receives the first light beam; a second light receiving element that receives scattered light after the second light beam is incident on an examination part of a biological body and is scattered; a differential circuit that connects the first light receiving element and the second light receiving element; a signal processing unit that obtains biological fluid information by processing the light detection signal output via the differential circuit; and a first light shielding unit that reduces the incidence of the scattered light on the first light receiving element.

[0004] In this biological information acquisition device, light branching for differential amplification, return light prevention for noise reduction, oblique irradiation, and the like are performed using independent elements.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-144578

[0008] In the biological information acquisition device described in Patent Document 1, since each function is realized by a plurality of independent components, the device becomes large and cannot be used as a wearable device. Summary of the Invention

[0009] The biological fluid information acquisition device of the present invention is characterized in that:

[0010] A light source, emitting laser light;

[0011] a prism that splits the laser light emitted from the light source into a first light beam and a second light beam;

[0012] a first light receiving element, receiving the first light beam;

[0013] a second light receiving element for receiving scattered light from the biological body caused by the second light beam incident on the examination site of the biological body;

[0014] a differential circuit that generates a light detection signal based on outputs of the first light receiving element and the second light receiving element; and

[0015] a signal processing unit that generates biological fluid information by processing the light detection signal;

[0016] The prism is plate-shaped or column-shaped,

[0017] The prism has a first boundary surface that branches the laser light emitted from the light source into the first light beam and the second light beam;

[0018] a second boundary surface that totally reflects the second light beam;

[0019] a third boundary surface that totally reflects the second light beam reflected by the second boundary surface; and

[0020] a fourth boundary surface, from which the second light beam reflected by the third boundary surface is emitted,

[0021] When the width direction of the biological fluid information acquisition device is set as the X direction and the thickness direction of the biological fluid information acquisition device, that is, the direction perpendicular to the X direction, is set as the Y direction, the distance between the second boundary surface and the third boundary surface in the Y direction is shorter than the distance between the first boundary surface and the fourth boundary surface in the X direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 1 and 2 are diagrams showing the main parts of an embodiment of a biological fluid information acquiring device according to the present invention.

[0023] Figure 2 yes Figure 1 The block diagram of the biological fluid information acquisition device shown.

[0024] Figure 3 Observed from the Z direction Figure 1 A side view of the prism of the biological fluid information acquisition device is shown.

[0025] Figure 4 Observed from the Z direction Figure 1 A side view of the prism of the biological fluid information acquisition device is shown.

[0026] Figure 5 When the angle θa is 30°, the Figure 1 A side view of the prism of the biological fluid information acquisition device is shown.

[0027] Figure 6 When the angle θa is -10°, the Figure 1 A side view of the prism of the biological fluid information acquisition device is shown.

[0028] Figure 7 Observed from the Z direction Figure 1 A side view of the prism of the biological fluid information acquisition device is shown.

[0029] Figure 8 Observed from the Z direction Figure 1 A side view of the prism of the biological fluid information acquisition device is shown.

[0030] Description of Reference Numerals

[0031] 1: Biofluid information acquisition device; 2: Circuit board; 3: Light source; 4: Prism; 41: First boundary surface; 42: Second boundary surface; 43: Third boundary surface; 44: Fourth boundary surface; 45: Fifth boundary surface; 46: Sixth boundary surface; 47: Polarization separation film; 5: First light-receiving element; 6: Second light-receiving element; 7: Differential circuit; 8: Signal processing unit; 9: Control unit; 11: Storage unit; 12: Display unit; 13: Operation unit; 21: Collimating lens; 22: Converging lens; 23: Glass cover; 24: Light reflecting component; 31: Housing; 51: Optical axis; 52: Optical axis; 100: Biomolecule; A: Position; D0: Beam diameter; D1: Beam diameter; D2: Beam diameter; D3: Beam diameter; L: Laser light; L1: First beam; L2: Second beam; L3: Scattered light; P1: Center; P2: Center; P G : Center; P L : Vertex; P P : point; Q: line segment; QX: component; QY: component; R1: incident range; R2: incident range; R3: incident range; R4: incident range; t 1_4 : distance; t 2_3 : distance; t G : distance; t L_P : distance; θ: angle; θ1: angle of incidence; θ2: angle of incidence; θ3: angle of incidence; θa: angle of incidence. DETAILED DESCRIPTION

[0032] Hereinafter, the biological fluid information acquisition device of the present invention will be described in detail based on the embodiments shown in the drawings.

[0033] Implementation Method

[0034] Figure 1 1 and 2 are diagrams showing the main parts of an embodiment of a biological fluid information acquiring device according to the present invention. Figure 2 yes Figure 1 The block diagram of the biological fluid information acquisition device shown. Figure 3 Observed from the Z direction Figure 1 A side view of the prism of the biological fluid information acquisition device is shown. Figure 4 Observed from the Z direction Figure 1 A side view of the prism of the biological fluid information acquisition device is shown. Figure 5 When the angle θa is 30°, the Figure 1 A side view of the prism of the biological fluid information acquisition device is shown. Figure 6 When the angle θa is -10°, the Figure 1 A side view of the prism of the biological fluid information acquisition device is shown. Figure 7 Observed from the Z direction Figure 1 A side view of the prism of the biological fluid information acquisition device is shown. Figure 8 Observed from the Z direction Figure 1 A side view of the prism of the biological fluid information acquisition device is shown.

[0035] In addition, in this manual, for the sake of convenience, Figure 1 The upper side in the expression is referred to as “upper” or “above”, and the lower side is referred to as “lower” or “below”.

[0036] In addition, if Figure 1 As shown in the figure, the X-axis, Y-axis, and Z-axis are shown as three axes that are orthogonal to each other. The tip side of the arrow representing each axis is represented by "+": positive, and the base side is represented by "-": negative. Furthermore, the direction parallel to the X-axis is also referred to as the "X direction: X-axis direction," the direction parallel to the Y-axis is also referred to as the "Y direction: Y-axis direction," and the direction parallel to the Z-axis is also referred to as the "Z direction: Z-axis direction."

[0037] In addition, the width direction of the biological fluid information acquisition device 1 is referred to as the X direction, the thickness direction of the biological fluid information acquisition device 1 is referred to as the Y direction, and the length direction of the biological fluid information acquisition device 1 is referred to as the Z direction.

[0038] In each drawing, the center lines of the beams, that is, rays, are shown as the laser light L, the first beam L1 , the second beam L2 , and the scattered light L3 .

[0039] In addition, Figure 1 In FIG, a portion of the housing 31 of the biological fluid information acquisition device 1 is shown instead of the entire housing 31. Figure 2 In the figure, only part of the lines of each signal and each control are shown.

[0040] Figure 1 The biological fluid information acquiring apparatus 1 shown is an apparatus for acquiring biological fluid information of a subject as a living body 100 .

[0041] In addition, biological fluid information refers to information related to the fluid of the biological body 100, for example, blood flow, blood volume, blood flow velocity, pulse, blood pressure, pulse wave propagation velocity, arteriosclerosis, and volume pulse wave in the biological body 100.

[0042] In addition, the form of the biological fluid information acquisition device 1 is not particularly limited. For example, various forms can be listed, such as a form of being worn on the subject and a fixed form. In this embodiment, the case of a form suitable for being worn on the subject is described.

[0043] like Figure 1 and Figure 2 As shown, the biological fluid information acquisition device 1 includes a housing 31 that accommodates or supports various components of the biological fluid information acquisition device 1. The housing 31 is box-shaped, and its outer shape is a rectangular parallelepiped. It should be noted that the shape of the housing 31 is not limited to this.

[0044] The biological fluid information acquisition device 1 also includes a circuit board 2 having various electronic components, circuits, etc. The circuit board 2 is disposed in, or housed in, a housing 31 .

[0045] The biological fluid information acquisition device 1 includes a light source 3 that emits laser light L, a first light receiving element 5, a second light receiving element 6, a differential circuit 7, a signal processing unit 8 that generates biological fluid information, a control unit 9 that controls the operation of the biological fluid information acquisition device 1, a storage unit 11 that stores various information and programs, a display unit 12 that displays various information, and an operation unit 13 that serves as an input unit for performing various instructions and inputs. The light source 3, the first light receiving element 5, the second light receiving element 6, the differential circuit 7, the signal processing unit 8, the control unit 9, the storage unit 11, the display unit 12, and the operation unit 13 are each electrically connected to the circuit board 2, and predetermined components thereof are disposed on the circuit board 2.

[0046] The biological fluid information acquisition device 1 also includes a prism 4, a collimating lens 21, a condensing lens 22, a cover glass 23 serving as a cover plate, and a light reflecting member 24. The prism 4, the collimating lens 21, the condensing lens 22, and the light reflecting member 24 are arranged and housed in a housing 31. The cover glass 23 is arranged at the lower portion of the housing 31, i.e., at the end of the housing 31 on the - side in the Y direction, and is supported by the housing 31 so as to be exposed to the outside.

[0047] In addition, the circuit board 2 is arranged on the upper part of the housing 31, that is, the end of the housing 31 on the Y direction + side, and the light source 3, the first light receiving element 5 and the second light receiving element 6 are arranged on the upper part of the housing 31. In this case, the first light receiving element 5 is arranged on the upper part of the light source 3. Figure 1The left side in the X direction, that is, the - side, the second light receiving element 6 is arranged on the light source 3 Figure 1 The right side in the X direction, that is, the + side.

[0048] The prism 4 is disposed on the optical path between the light source 3 and the cover glass 23. The prism 4 has the function of splitting the laser light L emitted from the light source 3 into a first light beam L1 and a second light beam L2. The prism 4 and its related structures will be described in detail later.

[0049] Furthermore, the glass cover 23 is disposed on the Y-direction-side of the second light-receiving element 6 and at the lower portion of the housing 31, i.e., at the Y-direction-side end of the housing 31. This glass cover 23 is the portion that comes into contact with the living body 100 when the biological fluid information acquisition device 1 is worn on the living body 100, and serves to protect the interior of the biological fluid information acquisition device 1. The cover plate is not limited to the glass cover 23, and its constituent material is not limited to glass; for example, resin materials can be used. It should be noted that the glass cover 23 can also be separated from the living body 100 when the biological fluid information acquisition device 1 is worn on the living body 100.

[0050] The cover glass 23 is plate-shaped and light-transmissive, and the second light beam L2 emitted from the fourth boundary surface 44 of the prism 4 passes through the cover glass 23 , while the scattered light L3 obtained from the living body 100 also passes through the cover glass 23 .

[0051] Furthermore, the collimator lens 21 is disposed on the optical path between the light source 3 and the first boundary surface 41 of the prism 4 .

[0052] Furthermore, the condenser lens 22 is arranged on the optical path between the second light receiving element 6 and the cover glass 23 .

[0053] Furthermore, the light reflecting member 24 is disposed on the optical path between the first light receiving element 5 and the first boundary surface 41 of the prism 4. The light reflecting member 24 has the function of reflecting the first light beam L1 reflected by the first boundary surface 41 toward the first light receiving element 5. Examples of the light reflecting member 24 include a prism and a reflective plate.

[0054] The light source 3 has a function of emitting laser light L. The light source 3 is not particularly limited, and examples thereof include semiconductor lasers.

[0055] The first light receiving element 5 has a function of receiving the first light beam L1. The first light receiving element 5 is not particularly limited, and examples thereof include a photodiode and a phototransistor.

[0056] The second light receiving element 6 has a function of receiving scattered light L3 from the organism 100 when the second light beam L2 enters the inspection area of ​​the organism 100. The second light receiving element 6 is not particularly limited, and examples thereof include photodiodes and phototransistors.

[0057] Furthermore, the differential circuit 7 has a function of generating a light detection signal based on the outputs of the first light receiving element 5 and the second light receiving element 6. Specifically, the differential circuit 7 converts the detection currents output from the first light receiving element 5 and the second light receiving element 6 into voltage signals, generates a signal corresponding to the difference between the voltage signals, and outputs the signal as the light detection signal.

[0058] The signal processing unit 8 is configured to include a computing circuit such as a CPU (Central Processing Unit) and can be implemented as one or more processors. It reads and executes various programs stored in the storage unit 11. Furthermore, the signal processing unit 8 generates biological fluid information by processing the light detection signal. Known methods can be applied to obtain biological fluid information based on the light detection signal, and therefore, their description is omitted.

[0059] The control unit 9 is configured to include a computing circuit such as a CPU (Central Processing Unit) and can be implemented as one or more processors. The control unit 9 reads and executes various programs stored in the storage unit 11. This allows the control of the operation of the biological fluid information acquisition device 1, various calculations, and various determinations to be performed.

[0060] It should be noted that the processors that realize the control unit 9 and the signal processing unit 8 etc. may be provided separately, or all or part of them may be shared.

[0061] The storage unit 11 also stores various programs that can be executed by the control unit 9. Furthermore, the storage unit 11 can store various data input from the outside. For example, the storage unit 11 may include volatile memory such as RAM (Random Access Memory) and non-volatile memory such as ROM (Read Only Memory). It should be noted that the storage unit 11 is not limited to a non-detachable type and may also include a detachable external storage device.

[0062] The display unit 12 is an example of a notification unit for notifying information, and has a function of displaying various information, such as biological fluid information, etc. The display unit 12 is not particularly limited, and examples thereof include a liquid crystal display device, an organic EL display device, and the like.

[0063] The operation unit 13 is not particularly limited, and examples thereof include operation buttons, operation switches, and operation knobs. The subject can operate the operation unit 13 to perform various instructions and inputs on the biological fluid information acquisition apparatus 1.

[0064] Alternatively, a display input unit having the functions of both the display unit 12 and the operation unit 13 may be used instead of or in addition to the display unit 12 and the operation unit 13. For example, a touch panel may be used as the display input unit.

[0065] Next, the prism 4 and the structure related to the prism 4 will be described.

[0066] The prism 4 has a function of branching the laser light L emitted from the light source 3 into a first light beam L1 and a second light beam L2 .

[0067] The prism 4 is made of various resin materials, various glass materials, etc. The prism 4 may be integrally formed or may be made of a plurality of parts.

[0068] In addition, the prism 4 is in the shape of a plate or a column. Then, in this embodiment, when viewed from the Z direction, the prism 4 is Figure 1 as well as Figure 3 In the shape shown, the two surfaces of the prism 4 in the Z direction are plane. It should be noted that the shapes of the two surfaces of the prism 4 in the Z direction can also be other shapes.

[0069] Hereinafter, various conditions such as the shape, posture, and arrangement of the prism 4 when viewed from the Z direction will be described.

[0070] like Figure 1 as well as Figure 3 As shown, when viewed from the Z direction, prism 4 has a first boundary surface 41, a second boundary surface 42, a third boundary surface 43, a fourth boundary surface 44, a fifth boundary surface 45, and a sixth boundary surface 46, which serve as boundaries with air. Each boundary surface 41-46 is a surface portion of prism 4. Furthermore, each boundary surface 41-46 is a plane and appears linear when viewed from the Z direction. It should be noted that in this specification, first boundary surface 41 is also referred to as "boundary surface 41," second boundary surface 42 is also referred to as "boundary surface 42," third boundary surface 43 is also referred to as "boundary surface 43," fourth boundary surface 44 is also referred to as "boundary surface 44," fifth boundary surface 45 is also referred to as "boundary surface 45," and sixth boundary surface 46 is also referred to as "boundary surface 46."

[0071] Boundary surface 41 of prism 4 splits laser light L emitted from light source 3 into first beam L1 and second beam L2.

[0072] Furthermore, a polarization separation film 47 is disposed on the boundary surface 41. Thus, the first light beam L1 as reflected light is S-polarized light, and the second light beam L2 as transmitted light is P-polarized light. Note that the polarization separation film 47 may be omitted.

[0073] Boundary surface 42 is a portion that totally reflects the second light beam L2 that has passed through boundary surface 41. Boundary surface 43 is a portion that totally reflects the second light beam L2 reflected by boundary surface 42. Boundary surface 44 is a portion from which the second light beam L2, reflected by boundary surface 43, is emitted. Boundary surfaces 45 and 46 are unused portions. It should be noted that in the drawings, the center lines, i.e., rays, of the laser light L, first light beam L1, and second light beam L2 are shown.

[0074] Furthermore, the boundary surfaces 41 to 46 are arranged clockwise from the boundary surface 41 in the order of the boundary surface 41 , the boundary surface 46 , the boundary surface 43 , the boundary surface 44 , the boundary surface 45 , and the boundary surface 42 .

[0075] Furthermore, the boundary surface 41 is disposed opposite to the boundary surface 44. Furthermore, the boundary surface 41 and the boundary surface 44 are parallel in the present embodiment, but are not limited thereto and may be non-parallel.

[0076] Furthermore, the boundary surface 42 is disposed opposite to the boundary surface 43. In addition, the boundary surface 42 and the boundary surface 43 are not parallel in the present embodiment, but are not limited thereto and may be parallel.

[0077] Furthermore, a boundary surface 45 is disposed between the boundary surface 42 and the boundary surface 44. Furthermore, one end of the boundary surface 45 is connected to the end of the boundary surface 42, and the other end of the boundary surface 45 is connected to the end of the boundary surface 44. The portion of the prism 4 where the boundary surface 45 is located is unused. By providing such a boundary surface 45, the shape of the prism 4 is configured such that a portion of the prism 4 is cut away. Therefore, the length of the prism 4 in the Y direction is shortened compared to a case where the boundary surface 45 is not provided. This allows the thickness of the biological fluid information acquisition device 1 to be reduced, enabling a more compact and thinner biological fluid information acquisition device 1.

[0078] Furthermore, boundary surface 46 is disposed between boundary surface 41 and boundary surface 43. Furthermore, one end of boundary surface 46 is connected to an end of boundary surface 43. Furthermore, the angle θ formed between boundary surface 43 and boundary surface 46 on the prism 4 side is greater than 180°. Thus, a cutout portion is formed in prism 4, formed by boundary surface 43 and boundary surface 46, thereby shortening the optical path length in prism 4. This allows the biological fluid information acquisition device 1 to be thinner and narrower, thereby miniaturizing the biological fluid information acquisition device 1.

[0079] In addition, the width direction of the biological fluid information acquisition device 1, that is, the width direction of the housing 31 is defined as the X direction, and the thickness direction of the biological fluid information acquisition device 1, that is, the thickness direction of the housing 31, which is a direction perpendicular to the X direction, is defined as the Y direction. In addition, the interval between the boundary surface 42 and the boundary surface 43 in the Y direction is defined as t 2_3 , the distance between the boundary surface 41 and the boundary surface 44 in the X direction is set to t 1_4 The t 2_3 is the distance between the boundary surface 42 and the boundary surface 43, t 1_4 is the distance between the boundary surface 41 and the boundary surface 44. When defined in this way, the distance between the boundary surface 42 and the boundary surface 43 in the Y direction, that is, the distance t 2_3 The distance t between the boundary surface 41 and the boundary surface 44 in the X direction is 1_4 As a result, the length of the prism 4 in the Y direction can be shortened, thereby enabling miniaturization, particularly thinning, of the biological fluid information acquisition device 1. This can reduce the burden on the subject.

[0080] Furthermore, in such a prism 4 , the second light beam L2 reflected on the boundary surface 43 can be prevented from being reflected on the boundary surface 44 and returning to the boundary surface 41 side within the prism 4 , thereby enabling accurate acquisition of biological fluid information.

[0081] Hereinafter, regarding various conditions of the prism 4 , preferred conditions will be described, but the present invention is not limited thereto.

[0082] When the beam diameter of the laser light L emitted from the light source 3 is set to D0,

[0083] The beam diameter of the laser light L on the boundary surface 41 is set to D1.

[0084] The beam diameter of the second light beam L2 on the boundary surface 42 is set to D2.

[0085] The beam diameter of the second light beam L2 on the boundary surface 43 is set to D3.

[0086] The incident angle of the laser light L on the boundary surface 41 is θ1.

[0087] The incident angle of the second light beam L2 on the boundary surface 42 is set to θ2,

[0088] The distance between the boundary surface 41 and the boundary surface 44 is t 1_4 When the distance t 1_4 The following formula (1) is satisfied.

[0089]

Mathematical formula 1

[0090]

[0091] This can prevent the second light beam L2 reflected on the boundary surface 43 from being reflected on the boundary surface 44 and returning to the boundary surface 41 side within the prism 4 , thereby enabling high-precision acquisition of biological fluid information.

[0092] It should be noted that the beam diameter D0 is the beam diameter after passing through the collimating lens 21 .

[0093] In addition, when the distance between the boundary surface 42 and the boundary surface 43 is t 2_3 When the distance t 2_3 The following formula (2) is satisfied.

[0094]

Mathematical formula 2

[0095]

[0096] This allows the length of the prism 4 in the Y direction to be shortened, thereby enabling miniaturization, particularly thinning, of the biological fluid information acquisition device 1 .

[0097] Note that the beam diameter D1 of the laser light L on the boundary surface 41 is expressed by the following equation (5).

[0098] D1=D0 / sin(90-θ1)…(5).

[0099] In addition, when the refractive index of the prism 4 is set to n t 、

[0100] Let the refractive index of air be n i ,

[0101] When the incident angle of the second light beam L2 on the boundary surface 43 is set to θ3,

[0102] The relationship of θ2≤θ3 is satisfied. This makes it possible to shorten the length of the prism 4 in the Y direction.

[0103] In addition, the incident angle θ2 satisfies the following formula (3).

[0104]

Mathematical formula 3

[0105]

[0106] In addition, the incident angle θ3 satisfies the following formula (4).

[0107]

Mathematical formula 4

[0108]

[0109] As a result, the incident angle of the second light beam L2 directed toward the living body 100 can be approximately 45°, which can suppress the entry of reflected light from the cover glass 23, thereby enabling high-precision acquisition of biological fluid information. Furthermore, the length of the prism 4 in the Y direction can be shortened, thereby enabling miniaturization, particularly reduction in thickness, of the biological fluid information acquisition device 1.

[0110] Here, in the above-mentioned formula (3), when θ2 is equal to or less than the value on the right side, total reflection does not occur at the boundary surface 42 due to the other conditions.

[0111] In the above-mentioned formula (3), when θ2 is equal to or larger than the value on the left side, the prism 4 becomes larger according to other conditions.

[0112] In the above-mentioned formula (4), when θ3 is equal to or less than the value on the right side, total reflection does not occur at the boundary surface 43 due to other conditions.

[0113] In the above-mentioned formula (4), when θ3 is equal to or larger than the value on the left side, the prism 4 becomes larger according to other conditions.

[0114] In addition, if Figure 4 As shown, when viewed from the Z direction, a line segment Q is assumed to connect the center P1 of the second light beam L2 on the boundary surface 42 and the center P2 of the second light beam L2 on the boundary surface 43. In this case, the center P1 is the center of the incident range R2 of the second light beam L2 on the boundary surface 42, and the center P2 is the center of the incident range R3 of the second light beam L2 on the boundary surface 43.

[0115] Then, the Y-direction component QY of the line segment Q is shorter than the X-direction component QX of the line segment Q. This shortens the Y-direction length of the prism 4 , thereby miniaturizing, particularly reducing, the thickness of the biological fluid information acquisition device 1 .

[0116] In addition, the posture of the prism 4 in the biological fluid information acquisition device 1 is not particularly limited and can be appropriately set according to the prescribed conditions. Figure 5 and Figure 6 As shown, the angle θa of the second boundary surface 42 relative to the cover glass 23 is not less than -10° and not more than 30° when viewed in the Z direction. This allows for a thinner biological fluid information acquisition device 1. The angle θa is based on the surface of the cover glass 23.

[0117] Figure 5 The case where the angle θa is +30° is shown. Figure 6 The angle θa is -10°, and the posture of the prism 4 relative to the cover glass 23 can be set within the above range. Therefore, the angle θa can be set to 0, for example, that is, the posture of the prism 4 can be set to a posture in which the second boundary surface 42 is parallel to the surface of the cover glass 23.

[0118] In addition, if Figure 7 As shown, the second light beam L2 incident on the glass cover 23 is at the center P of the incident surface of the glass cover 23. G The position of the center P is located closer to the prism 4 than the optical axis 52 of the condenser lens 22. In other words, the center P G This is the center of the incident range R4 of the second light beam L2 on the cover glass 23. This can improve the utilization efficiency of the scattered light L3 obtained from the examination site of the living body 100.

[0119] In addition, the center P G The distance t from the position A of the optical axis 52 on the incident surface of the glass cover 23 G Greater than 0 and less than 2 mm. This can improve the efficiency of using the scattered light L3 obtained from the inspection part of the biological body 100. G More preferably, it is 0.25 mm or more and 2 mm or less. This can further improve the utilization efficiency of the scattered light L3 obtained from the inspection site of the living body 100.

[0120] In addition, if Figure 8 As shown in FIG. 1 , when viewed from the Z direction, the point closest to the collimating lens 21 in the incident range R1 of the laser light L emitted from the light source 3 on the boundary surface 41 is defined as P. P In addition, the vertex on the boundary surface 41 side of the collimating lens 21 is set as P L .

[0121] Click P P With vertex P L The distance t in the direction of the optical axis 51 of the collimating lens 21 L_P Greater than 0.

[0122] This prevents the first light beam L1 reflected on the boundary surface 41 from interfering with the collimator lens 21 .

[0123] Then, based on Figure 1 and Figure 2 , the steps of acquiring biological fluid information by the biological fluid information acquiring device 1 and the operation of the biological fluid information acquiring device 1 are described.

[0124] First, the subject wears the biological fluid information acquiring device 1 on the living body 100 so that the cover glass 23 of the biological fluid information acquiring device 1 is placed at the examination site of the living body 100 .

[0125] When laser light L is emitted from light source 3, it passes through collimating lens 21 and becomes parallel light. It then enters boundary surface 41 of prism 4 and splits into a first light beam L1 and a second light beam L2 at boundary surface 41. Specifically, laser light L splits into first light beam L1, which is reflected by boundary surface 41, and second light beam L2, which is transmitted through boundary surface 41.

[0126] The first light beam L1 is reflected by the light reflecting member 24, enters the first light receiving element 5, and is received by the first light receiving element 5. The first light receiving element 5 outputs a detection current according to the amount of received light to the differential circuit 7.

[0127] The second light beam L2 is reflected by the boundary surface 42, reflected by the boundary surface 43, emitted from the boundary surface 44, passes through the cover glass 23, and enters the examination part of the living body 100, that is, irradiates it. As a result, scattered light L3 is emitted from the examination part of the living body 100.

[0128] Furthermore, scattered light L3 obtained from the examination site of the living body 100 is condensed by the condenser lens 22, incident on the second light receiving element 6, and received by the second light receiving element 6. Furthermore, a detection current corresponding to the amount of received light is output from the second light receiving element 6 to the differential circuit 7.

[0129] Furthermore, the differential circuit 7 converts the detection currents output from the first light receiving element 5 and the second light receiving element 6 into voltage signals, generates a signal corresponding to the difference between the voltage signals, and outputs the signal to the signal processing unit 8 as a light detection signal.

[0130] Furthermore, the signal processing unit 8 generates predetermined biological fluid information by processing the light detection signal. Examples of biological fluid information include blood flow rate, blood volume, blood flow velocity, pulse, blood pressure, pulse wave velocity, arteriosclerosis degree, and volume pulse wave.

[0131] In addition, the acquired biological fluid information is stored in the storage unit 11 and is read out as needed.

[0132] Furthermore, the acquired biological fluid information is displayed on the display unit 12. This allows the subject to grasp the biological fluid information.

[0133] As described above, according to the biological fluid information acquisition device 1, by using the prism 4, the length of the prism 4 in the Y direction can be shortened, thereby achieving miniaturization, especially thinning, of the biological fluid information acquisition device 1. This can reduce the burden on the subject.

[0134] Furthermore, the second light beam L2 reflected on the boundary surface 43 of the prism 4 can be prevented from being reflected on the boundary surface 44 and returning to the boundary surface 41 side within the prism 4 , thereby enabling high-precision acquisition of biological fluid information.

[0135] Other structures

[0136] The biological fluid information acquiring device 1 may also have the following structure, and this structure may also be applied to the aforementioned embodiment.

[0137] Structure 1

[0138] Alternatively, a predetermined amount, for example, 3%, of the laser light L emitted from the light source 3 is reflected by the first boundary surface 41 of the prism 4 and incident on the reference light receiving element as reference light. This improves the signal-to-noise ratio (SN ratio) of the light detection signal, thereby enabling high-precision acquisition of biological fluid information.

[0139] In addition, when a plate-shaped light branching element is used instead of the prism 4, it is necessary to consider not only the reflected light at the surface of the light branching element but also the reflected light at the back surface of the branching element, so a light amount adjustment mechanism needs to be provided. However, in this embodiment, since the prism 4 is used, a light amount adjustment mechanism does not need to be provided, thereby simplifying the structure.

[0140] Structure 2

[0141] A light shielding portion having an opening that allows a portion of the laser light L emitted from the light source 3 to pass through and shields the remaining portion may be provided on the first boundary surface 41 of the prism 4. The light shielding portion can be formed by, for example, pinhole processing.

[0142] Structure 3

[0143] At least a part of the differential circuit 7 may be constituted by a circuit including a differential amplifier or the like, and the light detection signal may be generated by this circuit.

[0144] Structure 4

[0145] At least a part of the difference circuit 7 may be constituted by an arithmetic processing unit that performs arithmetic processing, and the arithmetic processing unit performs arithmetic processing such as subtraction to calculate the light detection signal.

[0146] As described above, the biological fluid information acquisition device 1 includes: a light source 3 that emits laser light L; a prism 4 that branches the laser light L emitted from the light source 3 into a first light beam L1 and a second light beam L2; a first light receiving element 5 that receives the first light beam L1; a second light receiving element 6 that receives scattered light L3 obtained from the biological body 100 through the second light beam L2 incident on the inspection part of the biological body 100; a differential circuit 7 that generates a light detection signal based on the output of the first light receiving element 5 and the second light receiving element 6; and a signal processing unit 8 that generates biological fluid information by processing the light detection signal.

[0147] The prism 4 is plate-shaped or columnar. It also includes a first boundary surface 41 that splits the laser light L emitted from the light source 3 into a first light beam L1 and a second light beam L2; a second boundary surface 42 that totally reflects the second light beam L2; a third boundary surface 43 that totally reflects the second light beam L2 reflected by the second boundary surface 42; and a fourth boundary surface 44 through which the second light beam L2 reflected by the third boundary surface 43 is emitted.

[0148] In addition, when the width direction of the biological fluid information acquisition device 1 is set as the X direction and the thickness direction of the biological fluid information acquisition device 1, that is, the direction perpendicular to the X direction, is set as the Y direction, the distance between the second boundary surface 42 and the third boundary surface 43 in the Y direction is shorter than the distance between the first boundary surface 41 and the fourth boundary surface 44 in the X direction.

[0149] According to such a biological fluid information acquisition apparatus 1 , the length of the prism 4 in the Y direction can be shortened, thereby achieving miniaturization, particularly thinning, of the biological fluid information acquisition apparatus 1 , thereby reducing the burden on the subject.

[0150] Furthermore, the second light beam L2 reflected on the third boundary surface 43 of the prism 4 can be prevented from being reflected on the fourth boundary surface 44 and returning to the first boundary surface 41 side within the prism 4 , thereby enabling accurate acquisition of biological fluid information.

[0151] In the biological fluid information acquisition device 1, the beam diameter of the laser light L emitted from the light source 3 is set to D0.

[0152] The beam diameter of the second light beam L2 on the second boundary surface 42 is set to D2.

[0153] The beam diameter of the second light beam L2 on the third boundary surface 43 is set to D3.

[0154] The incident angle of the laser light L on the first boundary surface 41 is θ1.

[0155] The incident angle of the second light beam L2 on the second boundary surface 42 is set to θ2.

[0156] The distance between the first boundary surface 41 and the fourth boundary surface 44 is set to t 1_4 When the distance t 1_4 The following formula (1) is satisfied.

[0157]

Mathematical formula 5

[0158] .

[0159] This can prevent the second light beam L2 reflected on the third boundary surface 43 from being reflected on the fourth boundary surface 44 and returning to the first boundary surface 41 side within the prism 4 , thereby enabling accurate acquisition of biological fluid information.

[0160] In the biological fluid information acquisition device 1, the beam diameter of the laser light L emitted from the light source 3 is set to D0.

[0161] The beam diameter of the second light beam L2 on the second boundary surface 42 is set to D2.

[0162] The incident angle of the laser light L on the first boundary surface 41 is θ1.

[0163] The incident angle of the second light beam L2 on the second boundary surface 42 is set to θ2.

[0164] The distance between the second boundary surface 42 and the third boundary surface 43 is t 2_3 When the distance t 2_3 The following formula (2) is satisfied.

[0165]

Mathematical formula 6

[0166] .

[0167] This allows the length of the prism 4 in the Y direction to be shortened, thereby enabling miniaturization, particularly thinning, of the biological fluid information acquisition device 1 .

[0168] In addition, in the biological fluid information acquisition device 1, when the direction orthogonal to the X direction and the Y direction is set to the Z direction, when viewed from the Z direction, the component QY in the Y direction of the line segment Q connecting the center P1 of the second light beam L2 on the second boundary surface 42 and the center P2 of the second light beam L2 on the third boundary surface 43 is shorter than the component QX of the line segment Q in the X direction.

[0169] This allows the length of the prism 4 in the Y direction to be shortened, thereby enabling miniaturization, particularly thinning, of the biological fluid information acquisition device 1 .

[0170] Furthermore, the biological fluid information acquisition device 1 includes a housing 31 that houses the prism 4, and a cover glass 23 disposed within the housing 31 and serving as a cover plate through which the second light beam L2 emitted from the fourth boundary surface 44 passes. Furthermore, the angle θa of the second boundary surface 42 relative to the cover glass 23 is not less than -10° and not more than 30°. This allows the biological fluid information acquisition device 1 to be made thinner.

[0171] In addition, in the biological fluid information acquisition device 1, when the refractive index of the prism 4 is set to n t 、

[0172] Let the refractive index of air be n i ,

[0173] The beam diameter of the laser light L emitted from the light source 3 is set to D0.

[0174] The beam diameter of the second light beam L2 on the second boundary surface 42 is set to D2.

[0175] The incident angle of the laser light L on the first boundary surface 41 is θ1.

[0176] The incident angle of the second light beam L2 on the second boundary surface 42 is set to θ2.

[0177] When the incident angle of the second light beam L2 on the third boundary surface 43 is set to θ3,

[0178] The incident angle θ2 satisfies the following formula (3), the incident angle θ3 satisfies the following formula (4), and θ2 ≤ θ3.

[0179]

Mathematical formula 7

[0180] .

[0181]

Mathematical formula 8

[0182] .

[0183] As a result, the incident angle of the second light beam L2 directed toward the living body 100 can be approximately 45°, which can suppress the entry of reflected light from the cover glass 23, thereby enabling high-precision acquisition of biological fluid information. Furthermore, the length of the prism 4 in the Y direction can be shortened, thereby enabling miniaturization, particularly reduction in thickness, of the biological fluid information acquisition device 1.

[0184] Furthermore, the biological fluid information acquisition device 1 includes: a housing 31 that houses the prism 4; a condenser lens 22 disposed in the housing 31 that focuses the scattered light L3 onto the second light receiving element 6; and a cover glass 23 disposed in the housing 31 that serves as a cover plate through which the second light beam L2 emitted from the fourth boundary surface 44 passes. Furthermore, when a direction perpendicular to the X and Y directions is defined as the Z direction, the second light beam L2 incident on the cover glass 23 is at the center P of the cover glass 23 when viewed from the Z direction. G The position is located closer to the prism 4 than the optical axis 52 of the condenser lens 22, and the center P G The distance t from the position A of the optical axis 52 on the glass cover 23 G Greater than 0 and less than 2 mm.

[0185] This can improve the utilization efficiency of the scattered light L3 obtained from the inspection site of the biological body 100.

[0186] In addition, the biological fluid information acquisition device 1 includes a collimator lens 21, which is arranged between the light source 3 and the first boundary surface 41. The laser light L emitted from the light source 3 passes through the collimator lens 21. When the direction perpendicular to the X direction and the Y direction is defined as the Z direction, the laser light L emitted from the light source 3 is located at the point P closest to the collimator lens 21 in the incident range R1 on the first boundary surface 41 when viewed from the Z direction. P The vertex P on the first boundary surface 41 side of the collimating lens 21 L The distance t in the direction of the optical axis 51 of the collimating lens 21 L_P Greater than 0.

[0187] This can prevent the first light beam L1 reflected by the first boundary surface 41 from interfering with the collimator lens 21 .

[0188] In the biological fluid information acquisition apparatus 1 , when the direction perpendicular to the X and Y directions is defined as the Z direction, the prism 4 has a fifth boundary surface 45 between the second boundary surface 42 and the fourth boundary surface 44 when viewed from the Z direction.

[0189] By setting such a boundary surface 45, the shape of the prism 4 is set to a shape in which a part of the prism 4 is cut off. Therefore, compared with the case where the boundary surface 45 is not set, the length of the prism 4 in the Y direction becomes shorter, thereby making it possible to make the thickness of the biological fluid information acquisition device 1 thinner, and realizing the miniaturization and thinning of the biological fluid information acquisition device 1.

[0190] The above description of the biological fluid information acquisition device of the present invention is based on the illustrated embodiment. However, the present invention is not limited thereto, and the structure of each part can be replaced with any structure having the same function. In addition, any other structure can be added.

Claims

1. A biological fluid information acquisition device, characterized in that: have: A light source, emitting laser light; a prism that splits the laser light emitted from the light source into a first light beam and a second light beam; a first light receiving element, receiving the first light beam; a second light receiving element for receiving scattered light from the biological body caused by the second light beam incident on the examination site of the biological body; a differential circuit that generates a light detection signal based on outputs of the first light receiving element and the second light receiving element; as well as a signal processing unit that generates biological fluid information by processing the light detection signal; The prism is plate-shaped or column-shaped, The prism has a first boundary surface that branches the laser light emitted from the light source into the first light beam and the second light beam; a second boundary surface that totally reflects the second light beam; a third boundary surface that totally reflects the second light beam reflected by the second boundary surface; as well as a fourth boundary surface, from which the second light beam reflected by the third boundary surface is emitted, When the width direction of the biological fluid information acquisition device is set as the X direction and the thickness direction of the biological fluid information acquisition device, that is, the direction perpendicular to the X direction, is set as the Y direction, the distance between the second boundary surface and the third boundary surface in the Y direction is shorter than the distance between the first boundary surface and the fourth boundary surface in the X direction.

2. The biological fluid information acquisition device according to claim 1, characterized in that: Assuming that the beam diameter of the laser light emitted from the light source is D0, The beam diameter of the second light beam on the second boundary surface is set to D2, The beam diameter of the second light beam on the third boundary surface is set to D3, The incident angle of the laser on the first boundary surface is set to θ1, The incident angle of the second light beam on the second boundary surface is set to θ2, The distance between the first boundary surface and the fourth boundary surface is set to t 1_4 When the distance t 1_4 Satisfies the following formula (1): 。 3. The biological fluid information acquisition device according to claim 1, characterized in that: Assuming that the beam diameter of the laser light emitted from the light source is D0, The beam diameter of the second light beam on the second boundary surface is set to D2, The incident angle of the laser on the first boundary surface is set to θ1, The incident angle of the second light beam on the second boundary surface is set to θ2, The distance between the second boundary surface and the third boundary surface is set to t 2_3 When the distance t 2_3 Satisfies the following formula (2): 。 4. The biological fluid information acquisition device according to claim 1, characterized in that: When the direction perpendicular to the X direction and the Y direction is defined as the Z direction, When viewed in the Z direction, a line segment connecting the center of the second beam on the second boundary surface and the center of the second beam on the third boundary surface has a component in the Y direction shorter than a component in the X direction.

5. The biological fluid information acquisition device according to claim 1, characterized in that: The biological fluid information acquisition device comprises: a housing accommodating the prism; and a cover plate, disposed on the housing, through which the second light beam emitted from the fourth boundary surface passes, The angle of the second boundary surface relative to the cover plate is greater than or equal to -10° and less than or equal to 30°.

6. The biological fluid information acquisition device according to claim 1, characterized in that: When the refractive index of the prism is set to n t , Let the refractive index of air be n i , The beam diameter of the laser light emitted from the light source is set to D0. The beam diameter of the second light beam on the second boundary surface is set to D2, The incident angle of the laser on the first boundary surface is set to θ1, The incident angle of the second light beam on the second boundary surface is set to θ2, When the incident angle of the second light beam on the third boundary surface is set to θ3, The incident angle θ2 satisfies the following formula (3), the incident angle θ3 satisfies the following formula (4), and θ2≤θ3, ， 。 7. The biological fluid information acquisition device according to claim 1, characterized in that: The biological fluid information acquisition device comprises: a housing for accommodating the prism; a condenser lens, disposed on the housing, for focusing the scattered light onto the second light receiving element; as well as a cover plate, disposed on the housing, through which the second light beam emitted from the fourth boundary surface passes, When the direction perpendicular to the X direction and the Y direction is defined as the Z direction, Observed from the Z direction, The center position of the second light beam incident on the cover plate is located closer to the prism than the optical axis of the condenser lens. A distance between the center and the position of the optical axis on the cover plate is greater than 0 and is less than or equal to 2 mm.

8. The biological fluid information acquisition device according to claim 1, characterized in that: The biological fluid information acquisition device includes a collimating lens, which is arranged between the light source and the first boundary surface. The laser light emitted from the light source passes through the collimating lens. When the direction perpendicular to the X direction and the Y direction is defined as the Z direction, Observed from the Z direction, A distance between a point closest to the collimator lens in an incident range of the laser light emitted from the light source on the first boundary surface and a vertex of the collimator lens on the first boundary surface in the optical axis direction of the collimator lens is greater than 0.

9. The biological fluid information acquisition device according to claim 1, characterized in that: When the direction perpendicular to the X direction and the Y direction is defined as the Z direction, Observed from the Z direction, The prism has a fifth boundary surface between the second boundary surface and the fourth boundary surface.

Images