Pulse wave detection device

Abstract

To provide a pulse wave detection device that can accurately detect (measure) a pulse wave.SOLUTION: A pulse wave detection device (1A) includes a light shielding wall (17) in the vicinity of a light receiving element (15) to shield light mirrored at and reflected from a surface (100a) of an organism (100) and light reflected or scattered from other parts than the organism when a light-emitting device (13) emits light toward an organism so as to prevent light from being incident on the light receiving element (15).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pulse wave detecting device that detects (measures) the pulse wave of a living body. [Background technology]

[0002] A pulse wave detection device that uses a volume plethysmography method for measuring pulse waves is known as a device for detecting pulse waves of a living body. In a pulse wave measurement using the volume plethysmography method, for example, a light emitting unit (such as an LED) irradiates light onto a part of the living body (such as the wrist) that is pressed against a measurement window, and the light that passes through the living body and exits the living body is received by a light receiving unit (such as a photodiode or phototransistor), and the intensity of the received light is detected.

[0003] Examples of pulse wave sensors equipped with an optical sensor unit that acquires pulse wave data by irradiating light from a light-emitting unit onto a living body and detecting the intensity of the light that passes through the living body with a light-receiving unit include configurations disclosed in Patent Documents 1 and 2.

[0004] The pulse wave sensor of Patent Document 1 has a light-shielding wall between the light-emitting unit and the light-receiving unit. Providing the light-shielding wall blocks light that directly enters the light-receiving unit from the light-emitting unit, thereby improving the accuracy of detecting pulse wave data. The pulse wave sensor of Patent Document 1 is covered with a cover member having an opening smaller than the light-emitting area of ​​the light-emitting unit, preventing diffusion of the emitted light and blocking light that directly enters the light-receiving unit from the light-emitting unit, thereby improving the accuracy of detecting pulse wave data. The pulse wave sensor of Patent Document 1 is also covered with a cover member having an opening larger than the light-receiving area of ​​the light-receiving unit, blocking external light that leaks into the light-receiving unit, thereby improving the accuracy of detecting pulse wave data.

[0005] The sensor in Patent Document 2 has a light-shielding wall between the light-emitting element and the light-receiving element, and calculates the ratio of signals of different wavelengths to detect signals from a living organism.If the value is above a threshold, it is determined that the signal is from a living organism. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-63203 [Patent Document 2] US Patent Application Publication No. 2023 / 0404419 Summary of the Invention [Problem to be solved by the invention]

[0007] When detecting pulse wave data by irradiating a living body with light, a high AC / DC ratio (irrigation index) indicates high detection accuracy. The AC component is the component of the light incident on the light receiving unit that contains the pulse wave signal. The DC component is the component of the light incident on the light receiving unit that does not contain the pulse wave signal. In order to improve the detection accuracy of pulse wave data, it is effective to remove the DC component. There are four types of DC components: 1. Light components that enter (transmit) the body but do not contain pulse wave signals 2. The component of light that does not enter (pass through) the body and is specularly reflected from the surface of the body 3. The component of light that does not enter (transmit) into the body and is diffusely reflected on the surface of the body 4. Components of light that do not enter (pass through) the body, but are reflected or scattered by parts other than the body (panels, etc.).

[0008] When a pulse wave sensor is mounted in an earphone or a smart ring, a light-transmitting plate or material is often placed between the sensor and the living body for structural reasons and to protect the sensor. Furthermore, in the case of earphones, a gap may be created between the sensor and the living body. However, when a light-transmitting plate, material, or gap exists between the light-shielding wall of the pulse wave sensor and the living body, the above-mentioned conventional technology may not be able to sufficiently remove the DC component of light.

[0009] An object of one aspect of the present invention is to provide a pulse wave detecting device that can detect (measure) a pulse wave with high accuracy. [Means for solving the problem]

[0010] In order to solve the above problems, one aspect of the present invention provides a pulse wave detection device that includes an optical sensor unit, the optical sensor unit having a light-emitting element that emits light having a predetermined directivity angle, and a light-receiving element that receives light that is emitted from the light-emitting element, passes through the body from the surface of the living body, and emerges outside the body, the pulse wave detection device being configured such that a predetermined separation portion including a translucent material or an air gap is interposed between the light-emitting surface of the optical sensor unit and the surface of the living body, and the optical sensor unit further has a light-shielding wall provided between the light-emitting element and the light-receiving element that blocks light that is reflected without passing through the body so as not to enter the light-receiving element. [Effects of the Invention]

[0011] According to one aspect of the present invention, a pulse wave detecting device that can detect (measure) a pulse wave with high accuracy can be realized. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram showing an optical sensor portion which is a main part of a pulse wave detecting device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram illustrating an optical sensor unit in FIG. 1; [Figure 3] 2 is a diagram illustrating a light-emitting element provided in the optical sensor unit of FIG. 1. FIG. [Figure 4] 2 is a diagram illustrating a light-shielding wall provided in the optical sensor unit of FIG. 1. FIG. [Figure 5] 2 is a diagram illustrating a light-shielding wall provided in the optical sensor unit of FIG. 1. FIG. [Figure 6] 10 is a diagram showing an optical sensor portion which is a main part of a pulse wave detecting device according to another embodiment of the present invention. FIG. [Figure 7] 10 is a diagram showing an optical sensor portion which is a main part of a pulse wave detecting device according to another embodiment of the present invention. FIG. [Figure 8] 10 is a diagram showing an optical sensor portion which is a main part of a pulse wave detecting device according to another embodiment of the present invention. FIG. [Figure 9]10 is a diagram showing an optical sensor portion which is a main part of a pulse wave detecting device according to another embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] [Embodiment 1] A pulse wave detection device according to one embodiment of the present invention is described below. The pulse wave detection device includes an optical sensor unit. The optical sensor unit has a light-emitting element that irradiates light onto a living body, and a light-receiving element that receives part of the light that has passed through the living body and exits the body.

[0014] As an example, the pulse wave detection device may be configured in the form of an earphone or part of an earphone. The form is not limited to an earphone, and it may be a so-called smart ring. As another example, it may be configured to be worn around the wrist or ankle, or may be configured on other parts of the body (fingertips, forehead, between the eyebrows, tip of the nose, cheek, under the eyes, temple, earlobe, etc.). The pulse wave detection device may include components necessary to realize these forms. For example, if it is configured as a smart ring, it may include a ring-shaped structure that can be worn on a finger. If it is configured as an earphone, it may include a structure that can be worn on the ear.

[0015] As described above, pulse wave detection devices can be configured in various forms, but pulse wave detection devices are configured such that a predetermined separation portion, including a light-transmitting material or a gap, is interposed between the light-emitting surface of the optical sensor unit and the surface of the living body. Having a gap (separation portion) between the light-emitting surface of the optical sensor unit and the surface of the living body means that the light-emitting surface of the optical sensor unit is not pressed against the surface of the living body but is separated from it. When a light-transmitting material (separation portion) is present between the light-emitting surface of the optical sensor unit and the surface of the living body, the light-transmitting material may be pressed against the surface of the living body. The separation portion will be described later.

[0016] FIG. 1 schematically illustrates an optical sensor unit 10A, which is a main part of a pulse wave detection device 1A, and a portion of a living body 100, the subject of pulse wave measurement (detection). FIG. 1 shows a state during pulse wave acquisition, with the upper portion of FIG. 1, labeled A, illustrating a cross-sectional view of the optical sensor unit 10A along the direction of light emission from the light-emitting element 13. The lower portion of FIG. 1, labeled B, is a top view of the optical sensor unit 10A during pulse wave acquisition. Note that, without illustrating the living body 100, the portion of FIG. 1, labeled B, illustrates an irradiation surface 101 where light is irradiated from the light-emitting element 13 onto a surface 100a of the living body 100, and an emission region 103 where light irradiated onto the irradiation surface 101, which enters the living body 100 and is scattered within the living body 100, is emitted toward the light-receiving element 15. The emission region 103 is the same as the region obtained by projecting onto the XY plane the light scattering region 102 within the living body 100 of the light that has entered the living body 100 in the diagram A in Fig. 1. Note that Fig. 1 also shows three-dimensional coordinates in which the surface 100a (irradiation surface 101) of the living body 100 and the light emission surface 11 of the optical sensor unit 10A are defined as the XY plane, and the direction perpendicular to the XY plane is the Z-axis direction (third direction). Note that in this embodiment, the direction of the light emitted from the light-emitting element 13 toward the living body 100 is the positive direction of the Z-axis.

[0017] The optical sensor unit 10A has a light-emitting element 13, a light-receiving element 15, a light-shielding wall 17, and a holding unit 19. The holding unit 19 is formed of, for example, a substrate, and the light-emitting element 13, the light-receiving element 15, and the light-shielding wall 17 are held on the upper surface of the holding unit 19. The upper surface of the holding unit 19 is a surface parallel to the XY plane. The light-emitting element 13, the light-shielding wall 17, and the light-receiving element 15 are arranged side by side in this order along the Y-axis direction (first direction) that extends along the upper surface of the holding unit 19. The X-axis direction (second direction) is along the upper surface of the holding unit 19 and is perpendicular to the Y-axis direction.

[0018] The light emitting surface 11 of the optical sensor unit 10A is the surface facing the living body 100. In this embodiment, the optical sensor unit 10A is used at a distance from the surface 100a of the living body 100, and therefore the separation portion 20 between the light emitting surface 11 and the surface 100a of the living body 100 is an air gap. The light emitting surface 11 of the optical sensor unit 10A is flush with the light incident surface through which light incident on the light receiving element 15 enters the optical sensor unit 10A.

[0019] FIG. 2 shows two types of light emitting surface 11 (light incident surface) of optical sensor unit 10A. The type shown in upper A of FIG. 2 is a type equipped with a plate-shaped cover member 11A made of a light-transmitting material. Note that the type is not limited to the type equipped with cover member 11A, and an embodiment may be adopted in which the space between light emitting surface 11 and light-emitting element 13 or light-receiving element 15 is filled with a light-transmitting resin, as shown in lower B of FIG. 2. Note that, as shown in FIG. 2, the outer surfaces of optical sensor unit 10A, excluding the surface on the side where light emitting surface 11 is located, are surrounded by a light-shielding wall.

[0020] Here, the amount of light attenuation (absorbance) by biological tissue and venous blood (deoxygenated hemoglobin Hb) is constant, but the amount of light attenuation (absorbance) by arterial blood (oxygenated hemoglobin HbO2) varies over time due to pulsation. Therefore, the pulse wave detection device 1A of this embodiment measures the volume pulse wave by measuring changes in absorbance of the peripheral arteries using the "biological window" (a wavelength range in which light easily passes through a living body) in the visible to near-infrared range.

[0021] That is, the light emitting element 13 is a light emitting element that emits light of any wavelength within the wavelength range of 500 nm to 1000 nm.

[0022] Furthermore, the light emitting element 13 emits light having a directivity angle (sometimes referred to as a half-power angle or a light distribution angle) within a predetermined numerical range. As an example, the light emitting element 13 may be an LED element that emits light having a directivity angle of -50° to +50° as shown in the graph of FIG. 3. The light emitting element 13 is not limited to such an LED element, and may also be a surface emitting laser. A specific example of a surface emitting laser may be a VCSEL (Vertical Cavity Surface Emitting Laser), which is also shown in the graph of FIG. 3. An embodiment including a VCSEL will be described later.

[0023] The light emitting element 13 basically emits light along the positive Z-axis direction, but the light also spreads slightly in the positive and negative Y-axis directions in FIG. 1A.

[0024] When light emitted from such a light-emitting element 13 exits the light exit surface 11 of the optical sensor unit 10A, it is irradiated onto the surface 100a of the living body 100 (the irradiated surface is referred to as the irradiation surface 101). A portion of the light incident on the irradiation surface 101 enters the living body 100, while the other portion is specularly or diffusely reflected. The light that enters the living body 100 is scattered within the living body, and some of this scattered light is emitted from the living body 100. In a material that transmits a relatively large amount of light, such as the living body 100, the incident light penetrates (transmits) deep into the living body 100, diffuses, and scatters, and then exits the living body 100 even from a location far from the point of incidence (the irradiation surface 101). Below, the light exit region of the light that penetrates deep into the living body 100, diffuses, and scatters, and is emitted outside the living body 100 is indicated as 103. As shown in FIG. 1, the exit region 103 is larger than the irradiation surface 101.

[0025] For example, a photodiode (PD) is used as the light receiving element 15. This light receiving element 15 may be a standalone PD, or may be configured as part of an integrated circuit (IC) that integrates the PD with a circuit that performs analog-to-digital conversion of the output from the PD, a circuit that reduces noise, or a circuit that controls the light emitting element 13 and the PD.

[0026] A specific example of the size of the optical sensor unit 10A and each of its components can be as follows: In the following specific example, the "thickness" refers to the length in the Z-axis direction. Optical sensor part 10A size Thickness 0.75mm Width in the Y-axis direction: 2.5mm Width in the X-axis direction: 1.4mm Light-emitting element 13 Thickness 0.11mm Y-axis width: 0.28mm Width in the X-axis direction: 0.36mm 15 photodetectors (in the case of a single PD) Thickness 0.15mm Width in the Y-axis direction: 0.35mm Width in the X-axis direction: 0.35mm Photodetector 15 (in case of PD built into IC) Thickness 0.10mm (IC thickness) Width in the Y-axis direction: 0.20mm Width in the X-axis direction: 0.20mm Distance between the light-emitting element 13 and the light-receiving element 15: 1.5 mm The light-shielding wall 17 will be described later.

[0027] Furthermore, the predetermined separation portion 20 between the light emitting surface 11 of the optical sensor unit 10A and the surface 100a of the living body 100 is, as a specific example, a gap of 0.5 to 5.0 mm. In the pulse wave detecting device 1A of this embodiment, the length of the separation portion 20 is set to a predetermined value or within a predetermined numerical range.

[0028] When light is irradiated onto a living body 100, the light scattered within the living body 100 contains a pulse wave signal. The pulse wave signal is called an AC component because it changes periodically in accordance with the pulse rate. However, conventional pulse wave detection devices detect both the AC component, which contains the pulse wave signal, and the DC component, which does not contain the pulse wave signal, when light is irradiated onto a living body. There are four types of DC components: 1. A component of light that has entered (transmitted) the living body 100 but does not contain a pulse wave signal (hereinafter referred to as "DC component 1") 2. A component that does not enter (transmit) the living body 100 and is specularly reflected on the surface 100a of the living body 100 (hereinafter referred to as "DC component 2.") 3. A component that does not enter (transmit) the living body 100 and is diffusely reflected on the surface 100a of the living body 100 (hereinafter referred to as "DC component 3.") 4. A component that does not enter (transmit) into the living body 100, but is reflected or scattered by parts other than the living body 100 (panels, etc.) (hereinafter referred to as "DC component 4.").

[0029] The detection accuracy of the pulse wave signal is improved by increasing the AC / DC ratio (irrigation index), which is an index of the detection accuracy of the pulse wave signal. Therefore, in this embodiment, the light specularly reflected from the irradiation surface 101 (the above-mentioned DC component 2.) and the light reflected and scattered by parts other than the living body 100 (such as a panel) (the above-mentioned DC component 4.) are configured to be prevented from entering the light receiving element 15. Specifically, a light-shielding wall 17 is disposed near the light receiving element 15 to prevent light corresponding to (DC component 2.) and (DC component 4.) from being received by the light receiving element 15. In FIG. 1, the light blocked by the light-shielding wall 17 is indicated by a thick arrow.

[0030] 1, the light-shielding wall 17 is located between the light-emitting element 13 and the light-receiving element 15. Specifically, as shown in B in FIG. 1, the light-shielding wall 17 is located such that the center of the width in the X-axis direction of the light-emitting element 13 and the center of the width in the X-axis direction of the light-receiving element 15 are on an imaginary line L1 that connects the center of the width in the X-axis direction of the light-emitting element 13 and the center of the width in the X-axis direction of the light-receiving element 15.

[0031] Furthermore, as shown in Figure 1B, in top view (plan view), the width of the light-shielding wall 17 along the X-axis direction is sufficiently larger than the width of the light-emitting element 13 along the X-axis direction, and is also sufficiently larger than the width of the light-receiving element 15 along the X-axis direction.

[0032] The component of light (DC component 2) that is specularly reflected on the irradiation surface 101 is light whose angle of incidence on the irradiation surface 101 is equal to the angle of emission (reflection angle) of the light that is reflected and emitted. Therefore, the light-shielding wall 17 is disposed at a position where it can block the light that is specularly reflected on the irradiation surface 101 and that is farthest from the center of the optical axis (outermost light) among the light that has a predetermined directivity angle and is emitted from the light-emitting element 13.

[0033] Specifically, in order to block light (DC component 2.), the light-shielding wall 17 is positioned in the Y-axis direction at a position twice the distance (distance Wy in Figure 4) between the point at which the light farthest from the optical axis center in the Y-axis direction (the outermost light) reaches the irradiation surface 101 and the optical axis center, i.e., at a distance 2 x Wy from the optical axis center.

[0034] Furthermore, the height of light-shielding wall 17 in the Z-axis direction may be the same as the height of pulse wave detection device 1A (optical sensor unit 10A) in the Z-axis direction so that light (DC component 4.) reflected or scattered by parts other than living body 100 (such as the housing and the plate-like cover member described above) does not enter light receiving element 15. This can be said as meaning that the position of the upper end face of light-shielding wall 17 is at the same height as light exit surface 11 of optical sensor unit 10A, that is, the upper end face of light-shielding wall 17 is in the same plane as light exit surface 11.

[0035] Here, there is no particular restriction on the length (width) in the Y-axis direction of the baffle wall 17. The length in the X-axis direction of the baffle wall 17 is set to be at least twice the width of the distance (distance Wx in FIG. 5) between the center of the optical axis and the point where the light farthest from the center of the optical axis in the Y-axis direction (the outermost light) reaches the irradiation surface 101, that is, 2×Wx or more.

[0036] In summary, the conditions for arranging the light-shielding wall 17 to block the light of (DC component 2.) and (DC component 4.) are as follows: Y-axis direction: In FIG. 4, a position that is twice the distance Wy from the light-emitting element 13 X-axis direction: In FIG. 5, the width from the light-emitting element 13 is at least twice the distance Wx. Z-axis direction: same height as the optical sensor part 10A.

[0037] As a specific example, the width of the light-shielding wall 17 in the X-axis direction may be 2.0 mm, and as a specific example, the width of the light-shielding wall 17 in the Y-axis direction may be 0.2 mm.

[0038] The height of the light-shielding wall 17 in the Z-axis direction can be equal to or greater than the height of the light sensor unit 10A in the Z-axis direction. That is, the upper end surface of the light-shielding wall 17 is located at the same height as the light-emitting surface 11 or at a higher position. If the height of the light-shielding wall 17 in the Z-axis direction is lower than the height of the light sensor unit 10A in the Z-axis direction, the light (DC component 4) cannot be sufficiently blocked. Regarding the height of the light-shielding wall 17 in the Z-axis direction, in the embodiment shown in FIG. 2A in which a plate-shaped cover member 11A is disposed, the cover member 11A is disposed above the upper end surface of the light-shielding wall 17, but the thickness of the cover member 11A is very thin. Therefore, the height of the light-shielding wall 17 in the Z-axis direction can be considered to be equal to the height of the light sensor unit 10A.

[0039] The height of the light-shielding wall 17 in the Z-axis direction may be configured to be higher than the height of the optical sensor unit 10A in the Z-axis direction (i.e., the height of the light exit surface 11). This makes it possible to effectively block the light (DC component 2.) and the light (DC component 4.). Specifically, as in the optical sensor unit 10D of the pulse wave detection device 1D shown in FIG. 8, a light-shielding wall 17' separate from the light-shielding wall 17 may be disposed so as to be placed on the light-shielding wall 17 above the optical sensor unit 10A. Here, in FIG. 8A, the upper end surface of the light-shielding wall 17 is at the same height as the optical sensor unit 10A, and the separate light-shielding wall 17' is placed thereon. However, the boundary position between the light-shielding wall 17 and the light-shielding wall 17' is not limited to this and may be designed as appropriate. The light-shielding wall 17 and the light-shielding wall 17' may be integral. In other words, in this case, the light-shielding wall 17 has a convex portion formed thereon that protrudes beyond the light exit surface 11.

[0040] The width of the light-shielding wall 17 in the Y-axis direction is constant from the upper surface of the holder 19 to the light-emitting surface 11 of the optical sensor 10A. In other words, the surface of the light-emitting surface 11 of the optical sensor 10A shown in FIG. 1B is open except for the upper end surface of the light-shielding wall 17. This allows the area detectable by the light-receiving element 15 to include a wider area of ​​the light-emitting region 103, which is advantageous when receiving weak light such as pulse wave data. This also simplifies the manufacture of the light-shielding wall 17, which in turn simplifies the manufacture of the optical sensor 10A.

[0041] The light-shielding wall 17 may be made of resin, but is not limited to this.

[0042] In this embodiment, the provision of the light-shielding wall 17 limits the area that can be detected by the light receiving element 15 to an emission area 103 of light that has entered the living body 100 and is emitted from a light scattering area 102 within the living body 100 to the outside of the living body 100 in the diagram A in Fig. 1. Specifically, the light that has been emitted from the area 30 shown in Fig. 1 to the outside of the living body 100, i.e., scattered light 33 containing pulse wave data, is received by the light receiving element 15.

[0043] As described above, according to the configuration of this embodiment, light specularly reflected from the irradiation surface 101 (DC component 2.) and light reflected and scattered by parts other than the living body 100 (such as a panel) (DC component 4.) are not incident on the light receiving element 15, so the AC / DC ratio is relatively large and the pulse wave can be detected (measured) with high accuracy.

[0044] [Embodiment 2] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0045] FIG. 6 schematically illustrates an optical sensor unit 10B, which is a main part of a pulse wave detection device 1B of this embodiment, and a portion of a living body 100, the subject of pulse wave measurement (detection). FIG. 6 shows the state when a pulse wave is being acquired, and the upper view A in FIG. 6 is a cross-sectional view. The lower view B in FIG. 6 is a top view showing a plan view of the optical sensor unit 10B when a pulse wave is being acquired. Note that the view B in FIG. 6 does not show the living body 100, but illustrates an irradiation surface 101 where light is irradiated onto a surface 100a of the living body 100, and an emission region 103 where light irradiated onto the irradiation surface 101 enters the living body 100, is scattered within the living body 100, and is emitted toward a light receiving element.

[0046] The pulse wave detection device 1B of this embodiment differs from the pulse wave detection device 1A equipped with the optical sensor unit 10A of the above-described embodiment 1 in that a light-shielding wall 17 is provided to prevent the light receiving element 15 from receiving not only (DC component 2.) and (DC component 4.) of the four DC components mentioned above, but also light diffusely reflected on the surface 100a of the living body 100 (the above-described DC component 3.).

[0047] Light from the light-emitting element 13 is incident on the irradiation surface 101 of the surface 100a of the living body 100. Some of the light incident on the irradiation surface 101 of the surface 100a of the living body 100 enters the living body, and some does not enter the living body 100 and is specularly reflected or diffusely reflected at the surface 100a of the living body 100. Here, the specularly reflected or diffusely reflected light is referred to as living body surface reflected light. In this embodiment, a light-shielding wall 17 is arranged to prevent this living body surface reflected light from entering the light-receiving element 15. The optical path of the light component of this living body surface reflected light that is diffusely reflected at the surface 100a of the living body 100 is indicated by a thick arrow in Figure 6.

[0048] Here, light containing a component that is diffusely reflected on the surface 100a of the living body 100 (DC component 3.) is light in which the angle of incidence of the light incident on the surface 100a (irradiated surface 101) of the living body 100 from the light-emitting element 13 and the angle of reflection of the reflected light reflected on the irradiated surface 101 are different from each other.

[0049] The light-shielding wall 17 limits the area that can be detected by the light-receiving element 15 to an area 30 shown in the lower part of FIG. 6B within the emission area 103 of the light scattering area 102 of the living body 100.

[0050] The optical sensor unit 10B of this embodiment is configured such that the height of the light-shielding wall 17 in the positive direction of the Z axis is at least twice the height of the light-receiving element 15, at a position where it blocks the light reflected from the biological surface from entering the light-receiving element 15. The width of the light-shielding wall 17 in the X-axis direction, the width of the light-shielding wall 17 in the Y-axis direction, and the position of the light-shielding wall 17 in the Y-axis direction are the same as those of the light-shielding wall 17 of the first embodiment.

[0051] In this embodiment, the diameter of the irradiation surface 101 is larger than the size of the optical sensor unit 10B in the XY plane. In this case, the width of the light-shielding wall 17 in the X-axis direction can be made the same as the width of the optical sensor unit 10B in the X-axis direction. On the other hand, although not shown, if the diameter of the irradiation surface 101 is smaller than the size of the optical sensor unit 10B in the XY plane and larger than the size of the light-receiving element 15 in the XY plane, the width of the light-shielding wall 17 in the X-axis direction is made equal to or larger than the diameter of the irradiation surface 101.

[0052] As described above, in this embodiment, by providing the light-shielding wall 17, it is possible to configure the irradiation surface 101 on the surface 100a of the living body 100 and the area 30 that can be detected by the light-receiving element 15 so that they do not overlap. This makes it possible to realize the optical sensor unit 10B in which the reflected light from the living body surface does not enter the light-receiving element 15. Note that this is different from the optical sensor unit 10A of the first embodiment in which the irradiation surface 101 on the surface 100a of the living body 100 and the area 30 that can be detected by the light-receiving element 15 overlap.

[0053] [Embodiment 3] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0054] FIG. 7 schematically illustrates an optical sensor unit 10C, which is a main part of a pulse wave detection device 1C of this embodiment, and a portion of a living body 100, the subject of pulse wave measurement (detection). FIG. 7 shows the state when a pulse wave is being acquired, and the diagram A shown at the top of FIG. 7 is a cross-sectional view. The diagram B shown at the bottom of FIG. 7 is a top view showing a plan view of the optical sensor unit 10C when a pulse wave is being acquired. Note that the diagram B in FIG. 7 does not show the living body 100, but illustrates an irradiation surface 101 where light is irradiated onto a surface 100a of the living body 100, and an emission region 103 where light irradiated onto the irradiation surface 101 enters the living body 100, is scattered within the living body 100, and is emitted toward a light receiving element.

[0055] Pulse wave detecting device 1C of this embodiment differs from embodiments 1 and 2, which use LED elements, in that it employs the above-mentioned VCSEL as light emitting element 13. Pulse wave detecting device 1C of this embodiment also differs in that, due to the inclusion of a VCSEL as light emitting element 13, it employs a light-shielding wall 17 that is smaller in size than the light-shielding wall 17 of embodiments 1 and 2.

[0056] The VCSEL light-emitting element 13 can be configured to have a smaller beam angle than a light-emitting element using an LED element. Therefore, as shown in the lower part of FIG. 7B, the area of ​​the irradiation surface 101 is smaller than that of the light-receiving element in the first and second embodiments. The diameter of the irradiation surface 101 is smaller than the size of the light-receiving element in the XY plane. The wavelength of the VCSEL light-emitting element 13 may be the same as or different from the wavelength of the LED light-emitting element 13 described in the first and second embodiments, as long as it is in the range of 500 nm to 1000 nm. The beam angle is, for example, in the range of -5° to +5°.

[0057] Furthermore, since the area of ​​the irradiation surface 101 is thus small, the amount of light reflected from the living body surface of the living body 100 is also smaller than that in the first and second embodiments, and therefore the size of the light-shielding wall 17 can be configured to be smaller than the light-shielding wall 17 in the first and second embodiments. Specifically, in the optical sensor unit 10C, the width of the light-shielding wall 17 along the X-axis direction can be configured to be narrower than the light-shielding wall 17 in the first and second embodiments. In one example, the width of the light-shielding wall 17 along the X-axis direction can be made equal to the width of the light-receiving element 15 along the X-axis direction.

[0058] Furthermore, due to the reduced size of the light-shielding wall 17, the size of the optical sensor unit 10C in the XY plane can be configured to be smaller than the optical sensor units 10A and 10B of Embodiments 1 and 2. For example, the size of the optical sensor unit 10C in the XY plane can be set to the same size as PD in the X-axis direction (0.35 mm in this example).

[0059] Furthermore, by reducing the size of light-shielding wall 17 in the XY plane, it is possible to widen area 30 that can be detected by light-receiving element 15, i.e., the area that is not blocked by light-shielding wall 17. This allows scattered light 33 from living body 100, including the pulse wave signal, to be acquired from a wider area, thereby improving the strength of the pulse wave signal.

[0060] Furthermore, the configuration of this embodiment is more effective for light, such as red light or infrared light, whose absorption coefficient in hemoglobin is smaller than that of green light, because a small absorption coefficient in hemoglobin weakens the pulse wave signal, making it necessary to obtain a wide range of scattered light from the living body to improve detection accuracy.

[0061] If a light-emitting element having a smaller beam angle than an LED element, such as a VCSEL, is used as the light-emitting element 13, there is a great need for obtaining pulse wave data using red light, as this is necessary for detecting oxygen saturation. Also, if a light-emitting element having a smaller beam angle than an LED element, such as a VCSEL, is used as the light-emitting element 13, there is a great need for obtaining pulse wave data using infrared light, as infrared light is invisible.

[0062] According to this embodiment, since the area of ​​the irradiation surface 101 is small, the light corresponding to (DC component 2), (DC component 3), and (DC component 4) of the four DC components can be reduced compared to the configuration of embodiment 2. This makes it possible to achieve accurate pulse wave detection. In addition, scattered light 33 from the living body 100 can be acquired from a wider area, which contributes to further improving detection accuracy.

[0063] [Embodiment 4] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0064] In each of the above-described embodiments, the light emitting element 13 emits light in the positive direction of the Z axis. However, one aspect of the present invention is not limited to this, and the optical axis of the light emitting element 13 may be tilted with respect to the upper surface (XY plane) of the holder 19 so that the light emission direction is tilted away from the light receiving element 15.

[0065] According to the configuration of this embodiment, the irradiation surface 101 is farther away from the light receiving element 15. In Fig. 9, for comparison, the position of the irradiation surface 101 in embodiment 2 (Fig. 6) is indicated by a dashed dotted line, and the position of the irradiation surface 101 by the optical sensor unit 10E of this embodiment is indicated by a solid line. Compared to the irradiation surface 101 in embodiment 2 (Fig. 6), the irradiation surface 101 in this embodiment is farther away from the light receiving element 15. Therefore, the size of the light-shielding wall 17 can be reduced, and the area 30 that can be detected by the light receiving element 15, i.e., the area that is not blocked by the light-shielding wall 17, can be made wider.

[0066] The configurations of the above embodiments can provide a device that can easily and accurately acquire pulse wave data from a living body. Such effects also contribute to achieving, for example, Goal 3 of the Sustainable Development Goals (SDGs) advocated by the United Nations, "Ensure healthy lives and promote well-being for all at all ages."

[0067] 〔summary〕 Pulse wave detection devices 1A, 1B, 1C, and 1D according to a first aspect of the present invention are pulse wave detection devices 1A, 1B, 1C, and 1D each having an optical sensor unit 10A, 10B, 10C, and 10D, and each of the optical sensor units 10A, 10B, 10C, and 10D has a light-emitting element 13 that emits light having a predetermined directivity angle, and a light-receiving element 15 that receives light that is emitted from the light-emitting element 13, passes through the inside of the living body 100 from a surface 100a of the living body 100, and emerges outside the living body 100. 10C and 10D are configured such that a predetermined separation portion 20 including a translucent material or an air gap is interposed between the light emitting surface 11 of the optical sensor unit 10A, 10B, 10C and 10D and the surface 100a of the living body 100, and the optical sensor units 10A, 10B, 10C and 10D further have a light-shielding wall 17 provided between the light-emitting element 13 and the light-receiving element 15, which blocks light that is reflected without passing through the living body 100 from entering the light-receiving element 15.

[0068] According to the above configuration, it is possible to realize a pulse wave detecting device that can detect (measure) a pulse wave with high accuracy.

[0069] In the pulse wave detection devices 1A, 1B, 1C, and 1D according to aspect 2 of the present invention, in the above-mentioned aspect 1, the light-shielding wall 17 may be configured to block light emitted from the light-emitting element 13, which does not pass through the living body 100, and is specularly reflected on the surface 100a of the living body 100, from entering the light-receiving element 15.

[0070] According to the above configuration, it is possible to realize a pulse wave detecting device that can detect (measure) pulse waves with even greater accuracy.

[0071] In the pulse wave detection devices 1A, 1B, 1C, and 1D according to aspect 3 of the present invention, in the above-mentioned aspect 1 or 2, the light-shielding wall 17 may be configured to block light emitted from the light-emitting element 13 and reflected or scattered by parts other than the living body 100 from entering the light-receiving element 15.

[0072] According to the above configuration, it is possible to realize a pulse wave detecting device that can detect (measure) pulse waves with even greater accuracy.

[0073] In the pulse wave detection devices 1B and 1C according to aspect 4 of the present invention, in any of aspects 1 to 3 above, the light-shielding wall 17 may be configured to block light emitted from the light-emitting element 13, which does not pass through the living body 100, but is diffusely reflected by the surface 100a of the living body 100, from entering the light-receiving element 15.

[0074] According to the above configuration, it is possible to realize a pulse wave detecting device that can detect (measure) pulse waves with even greater accuracy.

[0075] A pulse wave measuring device 1C according to a fifth aspect of the present invention is any one of the first to fourth aspects, wherein the light emitting element 13 has a beam angle in the range of −5° to +5°.

[0076] According to the above configuration, the width of the light-shielding wall 17 can be reduced to match the width of the light-receiving element 15, so that scattered light 33 from the living body 100, including the pulse wave signal, can be acquired from a wider area, thereby improving the strength of the pulse wave signal.

[0077] Pulse wave detection devices 1A, 1B, 1C, 1D, and 1E according to a sixth aspect of the present invention are any of the first to fifth aspects, wherein the optical sensor unit further includes a holder capable of holding the light-emitting element, the light-shielding wall, and the light-receiving element on an upper surface, and the light-emitting element, the light-shielding wall, and the light-receiving element are arranged in this order in a first direction along the upper surface, and a direction perpendicular to the first direction along the upper surface is defined as a second direction, (i) in a plan view, when the diameter of the surface of the living body irradiated with light is larger than the optical sensor unit, the width of the light-shielding wall in the second direction is the same as the width of the optical sensor unit in the second direction, (ii) in a plan view, when the diameter of the surface of the living body irradiated with light is smaller than the optical sensor unit and larger than the light-receiving element, the width of the light-shielding wall in the second direction is equal to or greater than the diameter of the irradiation surface, and (iii) In a planar view, if the diameter of the light irradiation surface onto the surface of the living body is smaller than the light receiving element, the width of the light-shielding wall in the second direction may be greater than or equal to the width of the light receiving element in the second direction.

[0078] According to the above configuration, it is possible to realize a pulse wave detecting device that can detect (measure) pulse waves with even greater accuracy.

[0079] Pulse wave detection devices 1A, 1B, 1C, and 1D according to aspect 7 of the present invention may be configured in the above-mentioned aspect 6 such that the upper end surface of the light-shielding wall is located in the same plane as the light emission surface of the optical sensor portion.

[0080] According to the above configuration, it is possible to realize a pulse wave detecting device that can detect (measure) pulse waves with even greater accuracy.

[0081] The pulse wave detection devices 1A, 1B, 1C, and 1D according to aspect 8 of the present invention may be an optical sensor unit 10E configured such that, in any of aspects 1 to 7 above, the light-emitting element 13 is arranged with the light emission direction tilted away from the light-receiving element 15.

[0082] With the above configuration, irradiation surface 101 is farther from light receiving element 15 in plan view, so the size of light-shielding wall 17 can be reduced, making it possible to widen area 30 that can be detected by light receiving element 15, i.e., the area that is not blocked by light-shielding wall 17. This makes it possible to realize a pulse wave detection device that can detect (measure) pulse waves with even greater accuracy.

[0083] The pulse wave detection devices 1A, 1B, 1C, and 1D according to aspect 9 of the present invention may be an optical sensor unit 10D configured in any of aspects 1 to 8 above, which has a light-shielding wall 17' placed on the upper end surface of the light-shielding wall 17 and which is separate from the light-shielding wall 17, above the light exit surface 11.

[0084] According to the above configuration, it is possible to realize a pulse wave detection device that can effectively block light (DC component 2.) and light (DC component 3.), thereby detecting (measuring) pulse waves with even greater accuracy.

[0085] Pulse wave detection devices 1A, 1B, 1C, and 1D according to aspect 10 of the present invention may be configured such that, in any of aspects 1 to 9 above, the light-shielding wall 17 has a convex portion (light-shielding wall 17') formed thereon that protrudes beyond the light exit surface.

[0086] According to the above configuration, it is possible to realize a pulse wave detection device that can effectively block light (DC component 2.) and light (DC component 3.), thereby detecting (measuring) pulse waves with even greater accuracy.

[0087] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment. [Explanation of symbols]

[0088] 1A, 1B, 1C, 1D Pulse wave detector 10A, 10B, 10C, 10D, 10E Optical sensor part 11 Light exit surface 13 Light-emitting element 15 Photodetector 17 Blackout wall 19 Holding part 20 Separation part 100 Living organisms 100a surface 101 Irradiation surface 102 Light scattering area 103 Output area

Claims

1. A pulse wave detection device having an optical sensor unit, The optical sensor unit a light emitting element that emits light having a predetermined directivity angle; a light receiving element that receives light emitted from the light emitting element, transmitted through the living body from the surface of the living body, and exits the living body; and the pulse wave detection device is configured such that a predetermined separation portion including a translucent material or a gap is interposed between the light emitting surface of the optical sensor unit and the surface of the living body, The optical sensor unit further includes: a light-shielding wall provided between the light-emitting element and the light-receiving element, the light-shielding wall blocking light that has not passed through the living body and is reflected so as not to be incident on the light-receiving element; A pulse wave detection device characterized by:

2. the light-shielding wall blocks light emitted from the light-emitting element, which does not pass through the living body, and is specularly reflected on the surface of the living body, from entering the light-receiving element.

2. The pulse wave detecting device according to claim 1.

3. The light-shielding wall blocks light emitted from the light-emitting element and reflected or scattered by parts other than the living body so that the light does not enter the light-receiving element.

3. The pulse wave detecting device according to claim 1 or 2.

4. the light-shielding wall blocks light emitted from the light-emitting element, which does not pass through the living body, and is diffusely reflected on the surface of the living body, from entering the light-receiving element.

4. The pulse wave detecting device according to claim 3.

5. The light-emitting element has a beam angle in the range of −5° to +5°.

3. The pulse wave detecting device according to claim 1 or 2.

6. the optical sensor unit further includes a holder capable of holding the light-emitting element, the light-shielding wall, and the light-receiving element on an upper surface thereof, the light-emitting element, the light-shielding wall, and the light-receiving element are arranged in this order in a first direction along the top surface, When a direction perpendicular to the first direction along the upper surface is defined as a second direction, (i) when a diameter of a surface of the living body irradiated with the light is larger than a width of the optical sensor unit in a plan view, a width of the light-shielding wall in the second direction is the same as a width of the optical sensor unit in the second direction; (ii) when the diameter of the irradiation surface of the living body surface with the light is smaller than the optical sensor unit and larger than the light receiving element in a plan view, the width of the light-shielding wall in the second direction is equal to or larger than the diameter of the irradiation surface; (iii) When the diameter of the irradiation surface of the living body surface with the light is smaller than the light receiving element in a plan view, the width of the light-shielding wall in the second direction is equal to or greater than the width of the light receiving element in the second direction.

5. The pulse wave detecting device according to claim 4.

7. an upper end surface of the light-shielding wall is located in the same plane as the light exit surface of the optical sensor unit; 7. The pulse wave detecting device according to claim 6.

8. The light-emitting element is disposed so that the light emission direction is inclined away from the light-receiving element.

5. The pulse wave detecting device according to claim 4.

9. a light-shielding wall placed on an upper end surface of the light-shielding wall and separate from the light-shielding wall is provided above the light exit surface; 5. The pulse wave detecting device according to claim 4.

10. The light-shielding wall has a protrusion formed thereon that protrudes beyond the light-emitting surface.

5. The pulse wave detecting device according to claim 4.

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