Detection apparatus and measurement apparatus

Abstract

To provide a detection apparatus and a measurement apparatus capable of downsizing a device constitution.SOLUTION: The detection device comprises: a first light emitting part which emits first light with a green wavelength band; a second light emitting part which emits second light with a wavelength band higher than the green wavelength band; a first light receiving part which receives the first light emitted from the first light emitting part and ejected from a living body; and a second light receiving part which receives the second light emitted from the second light emitting part and ejected from the living body. The first light receiving part includes a band pass filter selectively transmits therethrough the light with the green wavelength band and the distance from the first light emitting part to the first light receiving part is shorter than the distance from the second light emitting part to the second light receiving part.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to detection and measurement devices. [Background technology]

[0002] Various measurement techniques for non-invasively measuring biological information such as pulse waves have been proposed. For example, the following Patent Document 1 discloses a technique for improving the light utilization efficiency of the light emitting unit and taking measures against stray light in the light receiving unit by installing a light shielding member between the light emitting unit and the light receiving unit in a detection device that includes a light emitting unit that emits light to a living body and a light receiving unit that receives the light that is emitted from the light emitting unit and reflected by the living body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-061675 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned detection device has a problem in that it is difficult to reduce the size of the device configuration because a thick light-shielding member must be provided between the multiple light-receiving sections. [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided a detection device comprising a first light-emitting unit that emits a first light having a green wavelength band, a second light-emitting unit that emits a second light having a wavelength band higher than the green wavelength band, a first light-receiving unit that receives the first light emitted from the first light-emitting unit and emitted from a living organism, and a second light-receiving unit that receives the second light emitted from the second light-emitting unit and emitted from the living organism, wherein the first light-receiving unit includes a bandpass filter that selectively transmits the first light, and the distance from the first light-emitting unit to the first light-receiving unit is shorter than the distance from the second light-emitting unit to the second light-receiving unit.

[0006] According to one aspect of the present invention, there is provided a detection device comprising a first light-emitting unit that emits a first light having a green wavelength band, a second light-emitting unit that emits a second light having a wavelength band higher than the green wavelength band, a first light-receiving unit that receives the first light emitted from the first light-emitting unit and emitted from a living organism, and a second light-receiving unit that receives the second light emitted from the second light-emitting unit and emitted from the living organism, wherein the distance from the first light-emitting unit to the first light-receiving unit is shorter than the distance from the second light-emitting unit to the second light-receiving unit, the first light-receiving unit includes a bandpass filter that selectively transmits the first light, and the second light-receiving unit does not include a bandpass filter that selectively transmits the second light.

[0007] According to one aspect of the present invention, there is provided a measurement device including the detection device of the above aspect, and an information analysis unit that identifies biological information from a detection signal that indicates a detection result by the detection device. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a side view of the measurement device according to the first embodiment. [Diagram 2] FIG. 1 is a configuration diagram focusing on the function of a measuring device. [Diagram 3] FIG. [Figure 4] 4 is a cross-sectional view taken along line IV-IV in FIG. 3. [Diagram 5] 1 is a graph showing the transmission spectrum of skin. [Figure 6] 1A and 1B are diagrams for explaining the operation of a detection device. [Figure 7] FIG. 11 is a plan view of a detection device according to a second embodiment. [Figure 8] 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following drawings, the scale and angle of each member are different from the actual scale and angle in order to make each member large enough to be recognizable.

[0010] (First embodiment) FIG. 1 is a side view of a measuring device 100 of the first embodiment. The measuring device 100 of the present embodiment shown in FIG. 1 is a bio-measuring device that non-invasively measures bio-information of a subject (e.g., a human being) that is an example of a living organism, and is attached to a part of the body of the subject that is to be measured (hereinafter referred to as a "measurement part") M. The measuring device 100 of the present embodiment is a wristwatch-type portable device that includes a housing part 1 and a belt 2, and can be attached to the subject's wrist by wrapping the band-shaped belt 2 around the wrist that is an example of the measurement part (living organism) M. In this embodiment, the subject's pulse wave (e.g., pulse rate) and oxygen saturation (SpO2) are exemplified as bio-information. The pulse wave means a time change in the volume of blood vessels linked to the heartbeat. The oxygen saturation means a ratio (%) of hemoglobin bound to oxygen to the hemoglobin in the subject's blood, and is an index for evaluating the subject's respiratory function.

[0011] Fig. 2 is a configuration diagram focusing on the functions of the measuring device 100. As shown in Fig. 2, the measuring device 100 of this embodiment includes a control device 5, a storage device 6, a display device 4, and a detection device 3. The control device 5 and the storage device 6 are installed inside the housing unit 1. As shown in Fig. 1, the display device 4 is installed on the surface of the housing unit 1 opposite to the measurement site M, and displays various images including measurement results under the control of the control device 5. The display device 4 is, for example, a liquid crystal display panel.

[0012] The detection device 3 is an optical sensor module that generates a detection signal S according to the state of the measurement site M. As shown in FIG. 1, the detection device 3 is installed, for example, on a surface (hereinafter referred to as a detection surface) 16 of the housing 1 that faces the measurement site M. The detection surface 16 is a surface that comes into contact with the measurement site M. As shown in FIG. 2, the detection device 3 of this embodiment includes a light-emitting unit 11, a light-receiving unit 12, a drive circuit 13, and an output circuit 14. It is also possible to install one or both of the drive circuit 13 and the output circuit 14 as external circuits of the detection device 3. That is, the drive circuit 13 and the output circuit 14 may be omitted from the detection device 3 .

[0013] The light-emitting unit 11 has a light-emitting section (first light-emitting section) 50, a light-emitting section (second light-emitting section) 60, and a light-emitting section (third light-emitting section) 70. The light-emitting section 50, the light-emitting section 60, and the light-emitting section 70 are light sources that each emit light of a different wavelength to the measurement site M.

[0014] The light emitting unit 50 emits green light (first light) LG having a green wavelength band of 520 nm to 550 nm toward the measurement site M. The green light LG in this embodiment is light with a peak wavelength of 520 nm, for example. The light emitting unit 60 emits red light (third light) LR having a red wavelength band of, for example, 600 nm to 800 nm toward the measurement site M. The red light LR in this embodiment is light having a peak wavelength of, for example, 660 nm. The light emitting unit 70 emits near-infrared light (second light) LI having a near-infrared wavelength band of, for example, 800 nm to 1300 nm toward the measurement site M. The near-infrared light LI in this embodiment is light having a peak wavelength of, for example, 905 nm.

[0015] As the light emitting elements constituting the light emitting units 50, 60, and 70, for example, bare chip type or bullet type LEDs (Light Emitting Diodes) are suitably used. The wavelength of the light emitted by each light emitting unit is not limited to the above numerical range. Hereinafter, when the light emitting units 50, 60, and 70 are not particularly distinguished from each other, they will be collectively referred to as the light emitting units 50, 60, and 70.

[0016] The drive circuit 13 causes each of the light-emitting units 50, 60, 70 to emit light by supplying a drive current. The drive circuit 13 of this embodiment causes each of the light-emitting units 50, 60, 70 to emit light periodically in a time-division manner. The light emitted from each of the light-emitting units 50, 60, 70 enters the measurement site M and propagates while repeatedly being reflected and scattered inside the measurement site M, and then is emitted to the housing 1 side and reaches the light-receiving unit 12. In other words, the detection device 3 of this embodiment is a reflective optical sensor in which the light-emitting unit 11 and the light-receiving unit 12 are located on one side of the measurement site M.

[0017] The light receiving unit 12 receives light coming from the measurement site M due to the emission of the light emitting unit 11. The light receiving unit 12 of this embodiment has a light receiving section (first light receiving section) 51 and a light receiving section (second light receiving section) 61. The light receiving section 51 and the light receiving section 61 generate detection signals according to the intensity of the received light. Hereinafter, when there is no particular distinction between the light receiving section 51 and the light receiving section 61, they are collectively referred to as "light receiving sections 51, 61."

[0018] The light receiving unit 51 receives the green light LG emitted from the light emitting unit 50 and propagated inside the measurement site M, and generates a detection signal according to the intensity of the received light. The light receiving unit 61 receives the red light LR emitted from the light emitting unit 60 and propagated inside the measurement site M, or the near-infrared light LI emitted from the light emitting unit 70 and propagated inside the measurement site M, and generates a detection signal according to the intensity of the received light.

[0019] The output circuit 14 is configured to include, for example, an A / D converter that converts the detection signals generated by each of the light receiving units 51, 61 from analog to digital, and an amplifier circuit that amplifies the converted detection signals (both not shown), and generates multiple detection signals S (S1, S2, S3) corresponding to different wavelengths.

[0020] The detection signal S1 is a signal representing the light receiving intensity of the light receiving unit 51 when receiving the green light LG emitted from the light emitting unit 50. The detection signal S2 is a signal representing the light receiving intensity of the light receiving unit 61 when receiving the red light LR emitted from the light emitting unit 60, and the detection signal S3 is a signal representing the light receiving intensity of the light receiving unit 61 when receiving the near-infrared light LI emitted from the light emitting unit 70.

[0021] Generally, the amount of light absorbed by blood differs when blood vessels are expanding and when they are contracting, so each detection signal S becomes a pulse wave signal that includes a periodic fluctuation component that corresponds to the pulsating component (volume pulse wave) of the artery inside the measurement site M.

[0022] The driving circuit 13 and the output circuit 14 are mounted on a wiring board in the form of IC chips together with the light-emitting unit 11 and the light-receiving unit 12. As described above, the driving circuit 13 and the output circuit 14 can also be installed outside the detection device 3.

[0023] The control device 5 is an arithmetic processing device such as a CPU (Central Processing Unit) or an FPGA (Field-Programmable Gate Array), and controls the entire measurement device 100. The storage device 6 is, for example, a non-volatile semiconductor memory, and stores the programs executed by the control device 5 and various data used by the control device 5. It is also possible to adopt a configuration in which the functions of the control device 5 are distributed among multiple integrated circuits, or a configuration in which some or all of the functions of the control device 5 are realized by a dedicated electronic circuit. It is also possible to realize the control device 5 including the storage device 6 by, for example, an ASIC (Application Specific Integrated Circuit) or the like in FIG. 2.

[0024] The control device 5 of this embodiment executes a program stored in the storage device 6 to identify the subject's biological information from the multiple detection signals S (S1, S2, S3) generated by the detection device 3. Specifically, the control device 5 identifies the subject's pulse wave from the detection signal S1 representing the light receiving intensity of the green light LG by the light receiving unit 51. The control device 5 can identify the subject's pulse rate, for example, based on the detection signal S1. The control device 5 can also identify the subject's oxygen saturation by analyzing the detection signal S2 representing the light receiving intensity of the red light LR by the light receiving unit 61 and the detection signal S3 representing the light receiving intensity of the near-infrared light LI by the light receiving unit 61.

[0025] As described above, the control device 5 functions as an information analysis unit that identifies biological information from the detection signal S that indicates the detection result by the detection device 3. The control device (information analysis unit) 5 causes the display device 4 to display the biological information identified from the detection signal S. It is also possible to notify the user of the measurement results by audio output. It is also preferable to configure the device to notify the user of a warning (possibility of impairment of physical function) if the pulse rate or oxygen saturation falls outside a predetermined range.

[0026] Fig. 3 is a plan view of the detection device 3. Fig. 4 is a cross-sectional view taken along the line IV-IV in Fig. 3. As shown in Figs. 3 and 4, the detection device 3 of this embodiment further includes a case 40, a light-shielding wall 41, and a sealing layer 42 in addition to the light-emitting unit 11 and the light-receiving unit 12. Note that the drive circuit 13 and the output circuit 14 are not shown in Figs. 3 and 4.

[0027] The configuration of the detection device 3 will be described below using the XYZ coordinate system. The X-axis corresponds to an axis along the long side (one side) of the case 40 having a rectangular outer shape, the Y-axis corresponds to an axis perpendicular to the X-axis and along the short side (the other side) of the case 40, and the Z-axis corresponds to an axis perpendicular to the X-axis and Y-axis, respectively, and along the normal to the detection surface 16 in contact with the measurement site M.

[0028] As shown in Figs. 3 and 4, the case 40 is a member that houses each element (the light-emitting unit 11 and the light-receiving unit 12) that constitutes the detection device 3. The case 40 has a box shape including a rectangular flat bottom surface 40a and a rectangular frame-shaped side plate 40b that protrudes from the periphery of the bottom surface 40a to the +Z side. The case 40 is made of aluminum, for example. An inner peripheral surface 40b1 of the side plate 40b is colored black to provide light blocking properties. This suppresses reflection on the inner peripheral surface 40b1 of the side plate 40b.

[0029] The case 40 may be made of any material and produced by any method. For example, the case 40 may be formed by injection molding of a resin material. Also, a configuration in which the case 40 is formed integrally with the housing 1 is suitable.

[0030] The light emitting unit 11 and the light receiving unit 12 are mounted on a wiring board (not shown) and placed on the bottom surface 40a of the case 40. The light shielding wall 41 is disposed between the light emitting unit 11 and the light receiving unit 12 in the direction along the X axis. The light shielding wall 41 is a plate-shaped member that protrudes from the bottom surface 40a to the +Z side and extends in the Y axis direction, and divides the storage space inside the case 40 into two in the X axis direction. That is, the light shielding wall 41 is a member that separates the spaces that store the light emitting unit 11 and the light receiving unit 12 in the direction along the X axis. The light shielding wall 41 is a member that has light shielding properties for blocking light emitted from the light emitting unit 11 from directly entering the light receiving unit 12.

[0031] In this embodiment, the light-shielding wall 41 is provided in the direction along the X-axis between the light-emitting unit 11 including the light-emitting section 50 and the light-emitting section 60 and the light-receiving section 51. In other words, the light-shielding wall 41 is a member that blocks a part of the green light LG, the red light LR, and the near-infrared light LI.

[0032] The sealing layer 42 is a light-transmitting resin material filled in the gap between the side plate 40b and the light-emitting unit 11 and the light-receiving unit 12 housed in the case 40. The sealing layer 42 seals (molds) the light-emitting unit 11 and the light-receiving unit 12 in the case 40. The surface of the sealing layer 42 functions as the detection surface 16. It is to be noted that a configuration in which the upper surface of the side plate portion 40b of the case 40 is covered with a light-transmitting substrate may be adopted instead of a configuration in which the sealing is performed with the sealing layer 42. In this case, the upper surface of the light-transmitting substrate functions as the detection surface 16.

[0033] The light emitting unit 11 is installed in the case 40 so that the light emitting surface of each of the light emitting parts 50, 60, 70 is parallel to the XY plane. That is, each of the light emitting parts 50, 60, 70 emits light toward the +Z side.

[0034] 3, the light-emitting sections 50, 60, and 70 are arranged side by side in a direction along the Y axis (first direction) at intervals from each other. Specifically, the light-emitting section 60 is arranged on the +Y side of the light-emitting section 50, and the light-emitting section 70 is arranged on the -Y side of the light-emitting section 50. That is, the light-emitting section 50 is arranged between the light-emitting sections 60 and 70 in the direction along the Y axis. In other words, the light-emitting section 50 is located between the light-emitting sections 60 and 70.

[0035] On the other hand, the light receiving unit 12 is installed in the case 40 so that the light receiving surfaces of the light receiving parts 51 and 61 are parallel to the XY plane. That is, the light receiving parts 51 and 61 are adapted to receive light incident from the Z direction.

[0036] 3, the light receiving units 51, 61 are spaced apart from each other and arranged side by side in a direction (second direction) along the X-axis intersecting (perpendicular to) the Y-axis. Specifically, the light receiving unit 51 is arranged on the +X side of the light emitting unit 11, and the light receiving unit 61 is arranged on the +X side of the light receiving unit 51. In other words, the light receiving unit 61 is arranged on the opposite side to the light emitting unit 11 with the light receiving unit 51 in between.

[0037] Here, the distance from the light-emitting unit 50 to the light-receiving unit 51 is D1, the distance from the light-emitting unit 60 to the light-receiving unit 61 is D2, and the distance from the light-emitting unit 70 to the light-receiving unit 61 is D3. The distance D1 corresponds to the distance between the centers of the light-emitting unit 50 and the light-receiving unit 51 when viewed in a plane from the Z-axis direction. The distance D2 corresponds to the distance between the centers of the light-emitting unit 60 and the light-receiving unit 61 when viewed in a plane from the Z-axis direction. The distance D3 corresponds to the distance between the centers of the light-emitting unit 70 and the light-receiving unit 61 when viewed in a plane from the Z-axis direction.

[0038] In the detection device 3 of this embodiment, the distance D1 from the light-emitting unit 50 to the light-receiving unit 51 is shorter than the distance D2 from the light-emitting unit 60 to the light-receiving unit 61. In addition, the distance D1 from the light-emitting unit 50 to the light-receiving unit 51 is shorter than the distance D3 from the light-emitting unit 70 to the light-receiving unit 61. The distances D2 and D3 are equal. In this manner, the detection device 3 of this embodiment employs a configuration in which the light receiving section 51 for receiving the green light LG is disposed in the position closest to the light emitting section 50 for emitting the green light LG.

[0039] As shown in FIG. 4, the light receiving unit 51 includes a light receiving element (first sensor unit) 510 that receives green light LG, an angle limiting filter (first angle limiting filter) 511 that limits the incident angle of the green light LG that reaches the light receiving element 510, and a bandpass filter 515 that selectively transmits the green light LG.

[0040] The light receiving element 510 is composed of, for example, a photodiode (PD). The angle limiting filter 511 is provided on a light receiving surface 510a of the light receiving element 510. The angle limiting filter 511 is formed, for example, by embedding a plug 513 made of a light blocking material such as tungsten in a silicon oxide layer 512 having optical transparency.

[0041] The silicon oxide layer 512 forms an optical path that guides light to the light receiving surface 510a of the light receiving element 510. The plug 513 embedded in the silicon oxide layer 512 limits the angle of incidence of light passing through the optical path (silicon oxide layer 512). That is, when the light entering the silicon oxide layer 512 is inclined at an angle greater than a predetermined angle with respect to the optical path, the incident light hits the plug 513, and a part of the light is absorbed by the plug 513, and the rest is reflected. Then, the intensity of the reflected light weakens due to repeated reflections before passing through the optical path, so that the light that can finally pass through the angle limiting filter 511 is substantially limited to light whose inclination with respect to the optical path is within a predetermined limiting angle.

[0042] The angle limiting filter 511 has a characteristic of transmitting light incident at an angle smaller than a predetermined incident angle and cutting off light incident at an angle larger than the predetermined incident angle without transmitting it. This enables the angle limiting filter 511 to limit the incident angle of light incident on the light receiving element 510. Specifically, the angle limiting filter 511 transmits green light LG incident at a predetermined incident angle (hereinafter referred to as the allowable incident angle) by propagating inside the living body, and cuts off light incident at an angle larger than the allowable incident angle, such as external light such as sunlight and light that has not entered the living body.

[0043] The bandpass filter 515 has the property of selectively transmitting the wavelength band of the green light LG and absorbing and cutting the other wavelength bands of the red light LR and the near-infrared light LI. The bandpass filter 515 is formed, for example, by alternately laminating a low refractive index layer such as silicon oxide and a high refractive index layer such as titanium oxide on the angle limiting filter 511.

[0044] On the other hand, the light receiving unit 61 includes a light receiving element (second sensor unit) 610 that receives red light LR or near-infrared light LI, and an angle limiting filter (second angle limiting filter) 611 that limits the angle of incidence of the red light LR or near-infrared light LI that reaches the light receiving element 610. That is, in the detection device 3 of this embodiment, the light receiving unit 61 has a configuration different from the light receiving unit 51 in that it does not include a bandpass filter that selectively transmits the red light LR or near-infrared light LI.

[0045] The light receiving element 610 is composed of, for example, a photodiode. The angle limiting filter 611 is provided on a light receiving surface 610a of the light receiving element 610. The angle limiting filter 611 has a configuration similar to that of the angle limiting filter 511, and can limit the incident angle of the red light LR or near-infrared light LI that reaches the light receiving element 610. The angle limiting filter 611 transmits, for example, the red light LR or near-infrared light LI that propagates inside the living body and is incident at an allowable incident angle, and cuts light that is incident at an angle larger than the allowable incident angle, such as external light such as sunlight and the red light LR or near-infrared light LI that has not passed inside the living body.

[0046] Figure 5 is a graph showing the transmission spectrum of skin. In Figure 5, the horizontal axis indicates the wavelength of light, and the vertical axis indicates the transmittance (unit: %). Figure 5 shows the transmission spectrum when the skin thickness is 0.43 mm as an example.

[0047] As shown in FIG. 5, when a wavelength band of green light LG (e.g., 520 nm) is incident on the skin, the transmittance is about 30%, when a wavelength band of red light LR (e.g., 660 nm) is incident on the skin, the transmittance is about 50% to 60%, and when a wavelength band of near-infrared light LI (e.g., 905 nm) is incident on the skin, the transmittance is about 60%.

[0048] The graph shown in FIG. 5 shows that the distance that light can propagate in a living body varies depending on the wavelength of light. That is, according to the graph in FIG. 5, it can be seen that the green light LG can only propagate a shorter distance in a living body than the red light LR or the near-infrared light LI. In other words, the red light LR and the near-infrared light LI can propagate farther in a living body than the green light LG. Note that FIG. 5 shows an example in which the skin is 0.43 mm thick, but even when the skin thickness is different, the red light LR and the near-infrared light LI can similarly propagate farther in a living body than the green light LG.

[0049] The operation of the detection device 3 of this embodiment will be described below. The detection device 3 of this embodiment includes a light-emitting unit 50 that emits green light LG, a light-emitting unit 60 that emits red light LR having a wavelength band higher than that of the green light LG, a light-emitting unit 70 that emits near-infrared light LI having a wavelength band higher than that of the green light LG, a light-receiving unit 51 that receives the green light LG emitted from the light-emitting unit 50 and emitted from the measurement site M, a light-receiving unit 61 that receives the red light LR emitted from the light-emitting unit 60 and emitted from the measurement site M, and a light-receiving unit 61 that receives the near-infrared light LI emitted from the light-emitting unit 70 and emitted from the measurement site M. The light-receiving unit 51 includes a bandpass filter 515 that selectively transmits the green light LG, and the distance D1 from the light-emitting unit 50 to the light-receiving unit 51 is shorter than the distance D2 from the light-emitting unit 60 to the light-receiving unit 61. In this embodiment, the distance D1 from the light-emitting unit 50 to the light-receiving unit 51 is shorter than the distance D3 from the light-emitting unit 70 to the light-receiving unit 61.

[0050] That is, in the detection device 3 of this embodiment, the light receiving unit 51 is disposed at a position closest to the light emitting unit 50 that emits the green light LG. When the light receiving unit 51 and the light emitting unit 50 are disposed close to each other in this manner, the green light LG emitted from the light emitting unit 50 propagates a short distance inside the living body and enters the light receiving unit 51. As shown in the graph of FIG. 5, since the green light LG can only propagate a short distance inside the living body as described above, if the distance between the light emitting unit 50 that emits the green light LG and the light receiving unit 51 that receives the green light LG is short, the green light LG emitted from the living body can enter the light receiving unit 51 with high intensity.

[0051] In the present embodiment, the light receiving unit 51 is disposed at a position closest to the light emitting unit 50, so that it is possible to maximize the amount of green light LG that propagates through the living body and enters the light receiving unit 51. Therefore, even if the amount of green light LG emitted by the light emitting unit 50 is suppressed, the detection device 3 can adequately detect the green light LG that has propagated through the living body at the light receiving unit 51. Therefore, the detection device 3 of this embodiment can accurately detect the green light LG at the light receiving section 51 while suppressing the amount of green light LG emitted from the light emitting section 50 and reducing the power consumption of the light emitting unit section 11.

[0052] Here, some of the red light LR and near-infrared light LI emitted from the light-emitting unit 60 may pass through the living body and enter the light-receiving unit 51. In the present embodiment, the light-receiving unit 51 includes a band-pass filter 515 that selectively transmits the green light LG. Therefore, the light-receiving unit 51 can cut the red light LR and near-infrared light LI that have a wavelength band different from that of the green light LG. Therefore, the light-receiving unit 51 can efficiently receive the green light LG emitted from the light-emitting unit 50.

[0053] FIG. 6 is a diagram for explaining the operation of the detection device 3. As shown in FIG. 6, a portion of the green light LG emitted from the light-emitting unit 50 may be reflected by the surface of the living body (measurement site M) and directly enter the light-receiving unit 51 without passing through the living body. Also, external light such as sunlight may directly enter the light-receiving unit 51 through a gap between the living body and the detection surface 16. Hereinafter, the green light LG that does not pass through the living body and heads toward the light-receiving unit 51 is referred to as the "first stray light component SL1," and the external light that heads directly toward the light-receiving unit 51 is referred to as the "second stray light component SL2."

[0054] Since the first stray light component SL1 has a green wavelength band, it passes through the bandpass filter 515 and is incident on the angle limiting filter 511 provided below the bandpass filter 515. As described above, the angle limiting filter 511 has the property of transmitting light incident at an angle smaller than the allowable incident angle and cutting off light incident at an angle larger than the allowable incident angle.

[0055] Since the first stray light component SL1 enters the light receiving unit 51 without passing through the living body, the angle of incidence of the green light LG to the light receiving unit 51 becomes larger than the allowable angle of incidence of the angle limiting filter 511. In other words, the first stray light component SL1 is cut by the angle limiting filter 511. As a result, the light receiving unit 51 can suppress the incidence of the first stray light component SL1 onto the light receiving surface 510a of the light receiving element 510 by the angle limiting filter 511.

[0056] The second stray light component SL2 is mostly cut by the bandpass filter 515, but the component having the green wavelength band included in the second stray light component SL2 passes through the bandpass filter 515. Here, as described above, the second stray light component SL2 is incident from the gap between the living body and the detection surface 16, so that the angle of incidence of the second stray light component SL2 with respect to the light receiving unit 51 becomes larger than the allowable angle of incidence of the angle limiting filter 511. Therefore, a part of the second stray light component SL2 (the component having the green wavelength band) that has passed through the bandpass filter 515 is cut by the angle limiting filter 511. As a result, the light receiving unit 51 can suppress the incidence of the second stray light component SL2 on the light receiving surface 510a of the light receiving element 510 by the angle limiting filter 511.

[0057] In this manner, in the detection device 3 of this embodiment, the green light LG emitted from the light-emitting unit 11 and passing through the living body can be made to enter the light-receiving surface 510a of the light-receiving element 510 efficiently. Furthermore, in the detection device 3 of this embodiment, it is possible to make it difficult for the first stray light component SL1 and the second stray light component SL2 to be incident on the light receiving surface 510a of the light receiving element 510.

[0058] Therefore, the light receiving section 51 can obtain a high S / N ratio by suppressing the incidence of the first stray light component SL1 and the second stray light component SL2, which are noise sources. Therefore, the detection device 3 of this embodiment can receive the green light LG with high accuracy at the light receiving section 51, and therefore can suppress the power consumption of the light emitting unit section 11 by suppressing the amount of light emitted by the light emitting section 50 of the green light LG.

[0059] In addition, in the detection device 3 of this embodiment, the distance (distance D2 or distance D3) between the light-emitting unit 60 and the light-emitting unit 70 and the light-receiving unit 61 is greater than the distance D1 between the light-emitting unit 50 and the light-receiving unit 51. In other words, the distance that the red light LR and the near-infrared light LI travel within the living body before being incident on the light-receiving unit 61 is greater than the distance that the green light LG travels within the living body before being incident on the light-receiving unit 51.

[0060] 5, the green light LG can only propagate a short distance inside the living body compared to the red light LR or the near-infrared light LI. Therefore, even if the green light LG propagates inside the living body so as to reach the light receiving unit 61, the green light LG is sufficiently attenuated while passing through the living body. Therefore, the green light LG cannot enter the light receiving unit 61.

[0061] On the other hand, the red light LR and the near-infrared light LI can propagate farther inside the living body than the green light LG. Therefore, even if the red light LR and the near-infrared light LI propagate a longer distance inside the living body than the green light LG, they can be incident with a sufficient amount of light on the light receiving section 61 that is farther away from the light emitting unit 11.

[0062] In the case of this embodiment, since only red light LR and near-infrared light LI are incident on the light receiving unit 61, there is no need to provide the light receiving unit 61 with a bandpass filter that selectively transmits the red light LR and near-infrared light LI and cuts off the green light LG. That is, in the detection device 3 of this embodiment, it is possible to adopt the above-mentioned configuration in which only the light receiving unit 51 includes the bandpass filter 515 and the light receiving unit 61 does not include a bandpass filter. Therefore, the detection device 3 of this embodiment can reduce costs by omitting the bandpass filter of the light receiving unit 61.

[0063] Furthermore, a portion of the red light LR emitted from the light-emitting unit 60, or a portion of the near-infrared light LI emitted from the light-emitting unit 70, may directly enter the light-receiving unit 61 without passing through the living body. Furthermore, external light such as sunlight may directly enter the light-receiving unit 61 through a gap between the living body and the detection surface 16. Hereinafter, the red light LR or near-infrared light LI that goes directly to the light-receiving unit 61 without passing through the living body will be collectively referred to as the "third stray light component SL3," and the external light that goes directly to the light-receiving unit 61 will be collectively referred to as the "fourth stray light component SL4."

[0064] Since the third stray light component SL3 is incident on the angle limiting filter 611 without passing through the living body, the incident angle of the third stray light component SL3 to the light receiving unit 61 becomes larger than the allowable incident angle of the angle limiting filter 611. In addition, since the fourth stray light component SL4 is incident from the gap between the living body and the detection surface 16, the incident angle of the fourth stray light component SL4 to the light receiving unit 61 becomes larger than the allowable incident angle of the angle limiting filter 611.

[0065] Therefore, the third stray light component SL3 and the fourth stray light component SL4 are effectively cut by the angle limiting filter 611. As a result, the light receiving unit 61 can suppress the incidence of the third stray light component SL3 and the fourth stray light component SL4 on the light receiving surface 610a of the light receiving element 610 by the angle limiting filter 611.

[0066] In this manner, in the detection device 3 of this embodiment, the red light LR or near-infrared light LI emitted from the light-emitting unit 11 and passing through the living body can be efficiently incident on the light-receiving surface 610a of the light-receiving element 610. Also, in the detection device 3 of this embodiment, it is possible to make it difficult for the third stray light component SL3 and the fourth stray light component SL4 to be incident on the light-receiving surface 610a of the light-receiving element 610.

[0067] Therefore, the light receiving section 61 can obtain a high S / N ratio by suppressing the incidence of the third stray light component SL3 and the fourth stray light component SL4, which are noise sources. According to the detection device 3 of this embodiment, the red light LR and the near-infrared light LI are efficiently received by the light receiving section 61, so that the amount of light emitted by each of the light emitting section 60 and the light emitting section 70 can be suppressed, thereby suppressing the power consumption of the light emitting unit section 11.

[0068] As described above, according to the detection device 3 of this embodiment, even if the amount of light emitted by the light-emitting sections 50, 60, and 70 is suppressed to reduce power consumption of the light-emitting unit 11, the light that has passed through the living body can be received with high accuracy by the light-receiving unit 12. Furthermore, in the detection device 3 of this embodiment, the bandpass filter in the light-receiving section 61 can be omitted to reduce costs.

[0069] Furthermore, in the detection device 3 of this embodiment, there is no need to provide a light-shielding member between the light receiving unit 51 and the light receiving unit 61 as in the conventional method to prevent stray light. This eliminates the need for space to provide a light-shielding member, and by preventing the detection device 3 from becoming larger, the device configuration can be made more compact.

[0070] Second embodiment Next, a detection device according to a second embodiment will be described. In the first embodiment, the light receiving unit 61 receives both the red light LR and the near-infrared light LI, but the detection device according to this embodiment is different from the first embodiment in that a light receiving unit that receives the red light LR and the near-infrared light LI separately is provided.

[0071] Fig. 7 is a plan view of the detection device of this embodiment. Fig. 8 is a cross-sectional view taken along line VIII-VIII in Fig. 7. Note that the same reference numerals are used for configurations and members common to the first embodiment, and detailed description will be omitted. As shown in Figures 7 and 8, the light receiving unit 112 in the detection device 3A of this embodiment has a light receiving section (first light receiving section) 151, a light receiving section (second light receiving section) 161, and a light receiving section (third light receiving section) 171.

[0072] The light receiving section 151 receives the green light LG that is emitted from the light emitting section 50 and propagates inside the measurement site M, and generates a detection signal according to the intensity of the received light. The light receiving section 161 receives near-infrared light LI that is emitted from the light emitting section 70 and propagates inside the measurement site M, and generates a detection signal according to the intensity of the received light. The light receiving section 171 receives the red light LR that is emitted from the light emitting section 60 and propagates inside the measurement site M, and generates a detection signal according to the intensity of the received light. That is, in this embodiment, the light-emitting unit 50 corresponds to the "first light-emitting unit", and the green light LG emitted from the light-emitting unit 50 corresponds to the "first light". The light-emitting unit 70 corresponds to the "second light-emitting unit", and the near-infrared light LI emitted from the light-emitting unit 70 corresponds to the "second light". The light-emitting unit 60 corresponds to the "third light-emitting unit", and the red light LR emitted from the light-emitting unit 60 corresponds to the "third light".

[0073] A detection device 3A of this embodiment differs from the detection device 3 of the above embodiment in that red light LR and near-infrared light LI are received separately by two light receiving parts (light receiving part 171 and light receiving part 161).

[0074] The light receiving unit 112 is installed in the case 40 so that the light receiving surfaces of the light receiving sections 151, 171, and 161 are parallel to the XY plane. Specifically, the light receiving section 151 is disposed on the +X side of the light emitting unit 11, the light receiving section 171 is disposed on the +X side of the light receiving section 151, and the light receiving section 161 is disposed on the +X side of the light receiving section 171. In other words, the light receiving section 171 is disposed between the light receiving sections 151 and 161.

[0075] In this embodiment, the distance from the light-emitting unit 50 to the light-receiving unit 151 is defined as D4. The distance D4 corresponds to the distance between the centers of the light-emitting unit 50 and the light-receiving unit 151 when viewed in a planar view from the Z-axis direction. Further, the distance from the light-emitting unit 70 to the light-receiving unit 161 is defined as D5. The distance D5 corresponds to the distance between the centers of the light-emitting unit 70 and the light-receiving unit 161 when viewed in a plan view from the Z-axis direction. Further, the distance from the light-emitting unit 60 to the light-receiving unit 171 is defined as D6. The distance D6 corresponds to the distance between the centers of the light-emitting unit 60 and the light-receiving unit 171 when viewed in a plan view from the Z-axis direction.

[0076] In the detection device 3A of this embodiment, the distance D4 from the light-emitting unit 50 to the light-receiving unit 151 is shorter than the distance D5 from the light-emitting unit 70 to the light-receiving unit 161. In addition, the distance D4 from the light-emitting unit 50 to the light-receiving unit 151 is shorter than the distance D6 from the light-emitting unit 60 to the light-receiving unit 171. Note that the distance D6 is shorter than the distance D5.

[0077] Similarly to the above embodiment, the detection device 3A of this embodiment also employs a configuration in which the light receiving section 151 for receiving the green light LG is disposed in the closest position to the light emitting section 50 that emits the green light LG.

[0078] The light receiving section 151 has the same configuration as the light receiving section 51 of the above embodiment. That is, the light receiving section 151 includes a light receiving element 510 that receives green light LG, an angle limiting filter 511, and a band pass filter 515.

[0079] In the detection device 3A of this embodiment, a light receiving section 161 that receives near-infrared light LI is configured to be disposed at a position farthest from the light emitting unit section 11. The light receiving section 161 has a configuration similar to that of the light receiving section 61 of the above embodiment. The light receiving section 161 includes a light receiving element (second sensor section) 1610 that receives near-infrared light LI, and an angle limiting filter (second angle limiting filter) 1611 that limits the incident angle of the near-infrared light LI that reaches the light receiving element 1610.

[0080] The green light LG can only propagate a short distance in the living body compared to the red light LR or the near-infrared light LI. Therefore, the green light LG does not reach the light receiving unit 161. Also, as shown in FIG. 5, the red light LR can propagate a shorter distance in the living body compared to the near-infrared light LI. Therefore, the red light LR is sufficiently attenuated in the living body before it reaches the light receiving unit 161, so the amount of red light LR incident on the light receiving unit 161 is small. Therefore, according to the detection device 3A of this embodiment, the bandpass filter that selectively transmits the near-infrared light LI can be omitted in the light receiving unit 161. Therefore, the detection device 3A of this embodiment can reduce costs by omitting the bandpass filter in the light receiving unit 161.

[0081] The light receiving unit 171 has a similar configuration to the light receiving unit 151. That is, the light receiving unit 171 includes a light receiving element 1710 that receives red light LR, an angle limiting filter 1711 that limits the angle of incidence of the red light LR that reaches the light receiving element 1710, and a band pass filter 1715 that selectively transmits the red light LR. The band pass filter 1715 has the property of selectively transmitting the wavelength band of the red light LR and absorbing and cutting the green light LG and near infrared light LI.

[0082] In the detection device 3A of this embodiment, the distance (distance D6) between the light-emitting unit 60 that emits the red light LR and the light-receiving unit 171 that receives the red light LR is shorter than the distance (distance D5) between the light-emitting unit 70 that emits the near-infrared light LI and the light-receiving unit 161 that receives the near-infrared light LI. Therefore, the green light LG that has propagated inside the living body may enter the light-receiving unit 171 in a state where it is not sufficiently attenuated. In addition, since the near-infrared light LI can propagate a longer distance inside a living body than the green light LG, there is a risk that the near-infrared light LI will be incident on the light receiving unit 171 with a stronger intensity than the green light LG. In contrast, in the present embodiment, the light receiving unit 171 is provided with a bandpass filter 1715, so that the red light LR can be efficiently incident on the light receiving element 1710.

[0083] According to the detection device 3A of this embodiment, it is possible to make it difficult for stray light components to enter the light receiving section 151, and to make the green light LG emitted from the light emitting unit section 11 and passing through the living body efficiently enter the light receiving section 151.

[0084] Moreover, according to the detection device 3A of this embodiment, it is possible to make it difficult for stray light components to be incident on the light receiving unit 171, and to make the red light LR emitted from the light emitting unit 11 and passing through the living body efficiently incident on the light receiving unit 171. Moreover, it is possible to make it difficult for stray light components to be incident on the light receiving unit 161, and to make the near-infrared light LI emitted from the light emitting unit 11 and passing through the living body efficiently incident on the light receiving unit 161.

[0085] As described above, according to the detection device 3A of this embodiment, the light receiving sections 151, 161, and 171 can receive light efficiently, so that it is possible to suppress the amount of light emitted by the light emitting sections 50, 60, and 70 and thereby suppress the power consumption of the light emitting unit section 11. Furthermore, according to the detection device 3A of this embodiment, a light blocking member as a measure against stray light is not necessary, so that the device configuration can be made more compact.

[0086] The present invention has been described above based on the above-mentioned embodiment, but the present invention is not limited to the above-mentioned embodiment and can be embodied in various forms without departing from the spirit of the present invention. For example, in the above embodiment, a human being is exemplified as a living body, but the present invention is also applicable to measuring biological information (for example, pulse rate) of other animals.

[0087] In addition, in the measuring device 100 of the above embodiment, the detection device 3 is provided inside the housing 1, but the installation location of the detection device 3 is not limited to this, and the detection device 3 may be embedded in the belt 2, for example. In addition, although a wristwatch-type configuration has been given as an example of the measuring device 100 in the above embodiment, the present invention can also be applied to, for example, a necklace-type configuration worn around the subject's neck, a sticker-type configuration worn by sticking it to the subject's body, or a head-mounted display-type configuration worn on the subject's head.

[0088] In addition, in the detection device 3 of the first embodiment described above, an example was given of each of the light-emitting units 50, 60, 70 emitting light in a time-division manner, but since the light-emitting unit 50 is individually provided with a light-receiving unit 61 corresponding to the green light LG of the light-emitting unit 50, the light-emitting unit 50 may be constantly lit rather than being time-division lit.

[0089] The detection device according to one aspect of the present invention may have the following configuration. A detection device of one embodiment of the present invention comprises a first light-emitting unit that emits a first light having a green wavelength band, a second light-emitting unit that emits a second light having a wavelength band higher than the green wavelength band, a first light-receiving unit that receives the first light emitted from the first light-emitting unit and emitted from a living body, and a second light-receiving unit that receives the second light emitted from the second light-emitting unit and emitted from the living body, wherein the first light-receiving unit includes a bandpass filter that selectively transmits the first light, and the distance from the first light-emitting unit to the first light-receiving unit is shorter than the distance from the second light-emitting unit to the second light-receiving unit.

[0090] Another embodiment of the detection device of the present invention comprises a first light-emitting unit that emits a first light having a green wavelength band, a second light-emitting unit that emits a second light having a wavelength band higher than the green wavelength band, a first light-receiving unit that receives the first light emitted from the first light-emitting unit and emitted from the living body, and a second light-receiving unit that receives the second light emitted from the second light-emitting unit and emitted from the living body, wherein the distance from the first light-emitting unit to the first light-receiving unit is shorter than the distance from the second light-emitting unit to the second light-receiving unit, the first light-receiving unit includes a bandpass filter that selectively transmits the first light, and the second light-receiving unit does not include a bandpass filter that selectively transmits the second light.

[0091] In one embodiment of the detection device of the present invention, the first light receiving unit may include a first sensor unit that receives a first light, and a first angle limiting filter that limits the angle of incidence of the first light that reaches the first sensor unit, and the second light receiving unit may include a second sensor unit that receives a second light, and a second angle limiting filter that limits the angle of incidence of the second light that reaches the second sensor unit.

[0092] In one embodiment of the detection device of the present invention, the first light-emitting unit and the second light-emitting unit may be arranged side by side in a first direction, and the first light-receiving unit and the second light-receiving unit may be arranged side by side in a second direction that intersects the first direction.

[0093] In one embodiment of the detection device of the present invention, the detection device may further include a third light-emitting unit that emits a third light, wherein the second light-emitting unit emits light in one of the red wavelength band or the near-infrared wavelength band as the second light, and the third light-emitting unit emits light in the other wavelength band of the red wavelength band or the near-infrared wavelength band as the third light, and the second light-receiving unit receives the third light emitted from the third light-emitting unit and emitted from the living body and the second light, and the distance from the first light-emitting unit to the first light-receiving unit may be shorter than the distance from the third light-emitting unit to the second light-receiving unit.

[0094] In one embodiment of the detection device of the present invention, the detection device may further include a third light-emitting unit that emits a third light, and a third light-receiving unit that receives the third light emitted from the third light-emitting unit and emitted from the living body, wherein the second light-emitting unit emits light in one of the red wavelength band or the near-infrared wavelength band as the second light, and the third light-emitting unit emits light in the other wavelength band of the red wavelength band or the near-infrared wavelength band as the third light, and the distance from the first light-emitting unit to the first light-receiving unit may be shorter than the distance from the third light-emitting unit to the third light-receiving unit.

[0095] In the detection device according to one aspect of the present invention, the first light-emitting section may be configured to be disposed between the second light-emitting section and the third light-emitting section in the first direction.

[0096] In one aspect of the detection device of the present invention, the detection device may further include a light-shielding wall provided between the first light-emitting section and the second light-emitting section and the first light-receiving section, for blocking a portion of the first light and the second light.

[0097] The measurement device according to one aspect of the present invention may have the following configuration. A measurement device according to one aspect of the present invention includes the detection device according to the above aspect, and an information analysis unit that identifies biological information from a detection signal indicating a detection result by the detection device. [Explanation of symbols]

[0098] 3, 3A...detection device, 5...control device (information analysis unit), 51, 151...light receiving unit (first light receiving unit), 61, 161...light receiving unit (second light receiving unit), 41...light shielding wall, 50...light emitting unit (first light emitting unit), 60...light emitting unit (second light emitting unit), 70...light emitting unit (third light emitting unit), 100...measuring device, 171...light receiving unit (third light receiving unit), 510...light receiving element (first sensor unit), 511...angle control limiting filter (first angle limiting filter), 515...bandpass filter, 610, 1610...light receiving element (second sensor unit), 611, 1611...angle limiting filter (second angle limiting filter), D1, D2, D3, D4, D5, D6...distance, LG...green light (first light), LI...near-infrared light (second light), LR...red light (third light), M...measurement site (living body).

Claims

1. a first light emitting unit that emits a first light having a green wavelength band; a second light emitting unit that emits second light having a wavelength band higher than the green wavelength band; a first light receiving unit that receives the first light emitted from the first light emitting unit and emitted from a living body; A second light receiving unit that receives the second light emitted from the second light emitting unit and emitted from the living body, the first light receiving unit includes a bandpass filter that selectively transmits the first light, A distance from the first light emitting unit to the first light receiving unit is shorter than a distance from the second light emitting unit to the second light receiving unit. Detection device.

2. a first light emitting unit that emits a first light having a green wavelength band; a second light emitting unit that emits second light having a wavelength band higher than the green wavelength band; a first light receiving unit that receives the first light emitted from the first light emitting unit and emitted from a living body; A second light receiving unit that receives the second light emitted from the second light emitting unit and emitted from the living body, a distance from the first light-emitting unit to the first light-receiving unit is shorter than a distance from the second light-emitting unit to the second light-receiving unit; the first light receiving unit includes a bandpass filter that selectively transmits the first light, The second light receiving unit does not include a bandpass filter that selectively transmits the second light.

3. the first light receiving unit includes a first sensor unit that receives the first light, and a first angle limiting filter that limits an incident angle of the first light that reaches the first sensor unit, The second light receiving unit includes a second sensor unit that receives the second light, and a second angle limiting filter that limits an incident angle of the second light that reaches the second sensor unit. The detection device according to claim 1 or 2.

4. The first light emitting unit and the second light emitting unit are arranged side by side in a first direction, The first light receiving portion and the second light receiving portion are arranged side by side in a second direction intersecting the first direction. Detecting device according to any one of claims 1 to 3.

5. Further comprising a third light emitting unit that emits a third light, The second light-emitting unit emits light in one of a red wavelength band and a near-infrared wavelength band as the second light, The third light-emitting unit emits light in the other wavelength band of a red wavelength band or a near-infrared wavelength band as the third light, The second light receiving unit receives the third light and the second light emitted from the third light emitting unit and emitted from the living body, A distance from the first light emitting unit to the first light receiving unit is shorter than a distance from the third light emitting unit to the second light receiving unit.

5. A detection device according to any one of claims 1 to 4.

6. a third light emitting unit that emits a third light; A third light receiving unit that receives the third light emitted from the third light emitting unit and emitted from the living body, The second light-emitting unit emits light in one of a red wavelength band and a near-infrared wavelength band as the second light, The third light-emitting unit emits light in the other wavelength band of a red wavelength band or a near-infrared wavelength band as the third light, A distance from the first light emitting unit to the first light receiving unit is shorter than a distance from the third light emitting unit to the third light receiving unit.

5. A detection device according to any one of claims 1 to 4.

7. The first light emitting portion is disposed between the second light emitting portion and the third light emitting portion in the first direction. The detection device according to claim 5 or 6.

8. a light-shielding wall provided between the first light-emitting unit and the first light-receiving unit, and configured to block a portion of the first light and the second light; Detection device according to any one of claims 1 to 7.

9. A detection device according to any one of claims 1 to 8; and an information analysis unit that identifies biological information from a detection signal indicating a detection result by the detection device. Measuring equipment.

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