Biological measurement device and biological measurement system

Abstract

A biological measurement device according to the present invention comprises a band-pass filter, a light detection device, and a processing circuit. The light detection device includes a first filter that transmits red light, a second filter that transmits green or blue light, a first light detection element that detects light from a living body via the first filter, and a second light detection element that detects light from the living body via the second filter. The processing circuit generates biological information about the living body on the basis of first light detected by the first light detection element and second light detected by the second light detection element. The band-pass filter suppresses transmission of at least a portion of light that, of light from the living body that is incident at the first light detection element, is in the wavelength range of 550–600 nm.

Description

Biometric measurement device and biometric measurement system

[0001] The present disclosure relates to a biometric device and a biometric system.

[0002] Conventionally, a method for acquiring biological information such as pulse wave information based on the reflected light generated by irradiating a living body with light has been known. However, when the living body moves, the reflected light contains not only biological information but also body movement information, making it difficult to accurately acquire biological information. Therefore, a method for removing body movement information has been proposed.

[0003] Patent Literature 1 discloses a pulse wave measuring device that uses a camera to measure the pulse wave of a living body. Image data of the living body acquired by the camera includes a green signal, which changes relatively greatly over time due to the pulse, and a red signal, which changes relatively little over time. The green signal includes not only pulse information but also body movement information, while the red signal includes only a small amount of pulse information and a large amount of body movement information. By correcting the green signal using the red signal, the body movement information can be removed from the information included in the green signal, making it possible to obtain pulse information.

[0004] Patent Document 2 discloses a pulse wave sensor that is attached to a living body. The pulse wave sensor detects reflected light generated by irradiating the living body with green light and outputs a green signal, and also detects reflected light generated by irradiating the living body with infrared light and outputs an infrared signal. The green signal contains not only pulse information but also body movement information, while the infrared signal contains only a small amount of pulse information and a large amount of body movement information. By comparing the frequency components of the green signal and the infrared signal, the body movement information can be removed from the information contained in the green signal, making it possible to obtain pulse information.

[0005] JP 2020-157102 A JP 2004-261366 A

[0006] A biometric measuring device capable of effectively acquiring biometric information is provided.

[0007] A biomeasurement device according to one aspect of the present disclosure comprises a bandpass filter, a photodetector, and a processing circuit, wherein the photodetector includes a first filter that transmits red light, a second filter that transmits one of green and blue light, a first photodetector element that detects light from a living organism through the first filter, and a second photodetector element that detects light from the living organism through the second filter, wherein the processing circuit generates biometric information of the living organism based on the first light detected by the first photodetector element and the second light detected by the second photodetector element, and the bandpass filter prevents at least a portion of the light from the living organism that is incident on the first photodetector element in the wavelength range of 550 nm or more and 600 nm or less from passing through.

[0008] A general or specific aspect of the present disclosure may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable recording disk, or as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. The computer-readable recording medium may include a non-volatile recording medium such as a CD-ROM (Compact Disc-Read Only Memory). An apparatus may be composed of one or more devices. When an apparatus is composed of two or more devices, the two or more devices may be located in a single device or may be located separately in two or more separate devices. In this specification and claims, the term "apparatus" may refer not only to a single device but also to a system consisting of multiple devices.

[0009] According to the technology of the present disclosure, a biometric measurement device capable of effectively acquiring biometric information can be realized.

[0010] FIG. 1 is a graph showing the absorption spectrum of oxygenated hemoglobin in blood. FIG. 2 is a graph showing the spectrum of a general color filter. FIG. 3 is a diagram schematically showing the configuration of a measurement device according to a first exemplary embodiment of the present disclosure. FIG. 4 is a graph showing an example of the spectrum of a bandpass filter and the absorption spectrum of oxygenated hemoglobin. FIG. 5 is a graph showing an example of the spectrum of a configuration in which a bandpass filter and a general color filter are combined. FIG. 6 is a diagram schematically showing example time-series data of a first signal and a second signal, and example biological information. FIG. 7 is a diagram schematically showing an example of the arrangement of color filters in a photodetector. FIG. 8 is a diagram schematically showing the configuration of a measurement device according to a second exemplary embodiment of the present disclosure. FIG. 9A is a diagram schematically showing a first exemplary configuration of a light source. FIG. 9B is a graph showing an example of an emission spectrum of light emitted from a light source. FIG. 10A is a diagram schematically showing a second exemplary configuration of a light source. FIG. 10B is a graph showing another example of the emission spectrum of light emitted from a light source. FIG. 10C is a graph showing yet another example of the emission spectrum of light emitted from a light source. FIG. 11 is a diagram schematically showing the configuration of a measurement device according to a third exemplary embodiment of the present disclosure. FIG. 12A is a graph showing an example of the spectrum of a first filter. FIG. 12B is a graph showing an example of the spectrum of a second filter. FIG. 12C is a graph showing an example of the spectrum of a third filter. FIG. 13A is a diagram schematically showing another example 1 of the spectrum of a bandpass filter. FIG. 13B is a diagram schematically showing another example 2 of the spectrum of a bandpass filter. FIG. 13C is a diagram schematically showing another example 3 of the spectrum of a bandpass filter. FIG. 14A is a diagram schematically showing another example 1 of the spectrum of a bandpass filter. FIG. 14B is a diagram schematically showing another example 2 of the spectrum of a bandpass filter. FIG. 14C is a diagram schematically showing another example 3 of the spectrum of a bandpass filter. Fig. 15 is a diagram showing a modified example of the timing of light emission from the light source. Fig. 16 is a diagram showing a state in which light from a living body passes through a telecentric lens, passes through a band-pass filter, and enters a photodetector.FIG. 17 is a diagram schematically illustrating a configuration of a bioinstrumentation system according to an exemplary embodiment of the present disclosure.

[0011] In the present disclosure, all or part of a circuit, unit, device, component, or part, or all or part of a functional block in a block diagram, may be implemented by one or more electronic circuits, including, for example, a semiconductor device, a semiconductor integrated circuit (IC), or an LSI (large scale integration). The LSI or IC may be integrated on a single chip or may be configured by combining multiple chips. For example, functional blocks other than memory elements may be integrated on a single chip. While the terms LSI and IC are used here, the term may be changed depending on the degree of integration, and may be referred to as a system LSI, a VLSI (very large scale integration), or an ULSI (ultra large scale integration). A Field Programmable Gate Array (FPGA), which is programmed after the LSI is manufactured, or a reconfigurable logic device, which can reconfigure the connection relationships within the LSI or set up circuit sections within the LSI, can also be used for the same purpose.

[0012] Furthermore, all or part of the functions or operations of a circuit, unit, device, component, or section can be implemented by software processing. In this case, the software is recorded on one or more non-transitory recording media such as ROMs, optical disks, hard disk drives, etc., and when the software is executed by a processor, the functions specified in the software are executed by the processor and peripheral devices. A system or device may include one or more non-transitory recording media on which the software is recorded, a processor, and required hardware devices, such as interfaces.

[0013] In this disclosure, "light" refers to electromagnetic waves including not only visible light (wavelengths of about 360 nm to about 800 nm), but also ultraviolet light (wavelengths of about 10 nm to about 360 nm) and infrared light (wavelengths of about 800 nm to about 1 mm).

[0014] Exemplary embodiments of the present disclosure will be described below. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, components, component placement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components that are not recited in the independent claims that represent the highest concepts will be described as optional components. Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Furthermore, in each figure, substantially identical components are assigned the same reference numerals, and duplicated descriptions may be omitted or simplified.

[0015] Before describing embodiments of the present disclosure, the principle of acquiring biometric information based on reflected light generated by irradiating a living body with light will be described. In the following description, pulse information will be used as an example of biometric information.

[0016] Fig. 1 is a graph showing the absorption spectrum of oxygenated hemoglobin in blood. As shown in Fig. 1, the absorption coefficient of oxygenated hemoglobin is relatively high in the wavelength range of 300 nm to 600 nm within the wavelength range of 300 nm to 900 nm, and relatively low in other wavelength ranges. The absorption coefficient of oxygenated hemoglobin is highest near 420 nm and is also relatively high in the wavelength range of 550 nm to 600 nm. Because the degree of light absorption by oxygenated hemoglobin changes depending on fluctuations in blood flow, the intensity of reflected light generated when a living body is irradiated with light reflects pulse information.

[0017] According to the absorption spectrum of oxygenated hemoglobin, when a living body is illuminated with blue or green light and the reflected light is detected, the blue or green detection signal contains a lot of pulse information, whereas when a living body is illuminated with red or infrared light and the reflected light is detected, the red or infrared detection signal contains only a small amount of pulse information.

[0018] In this specification, the red wavelength range corresponds to at least a part of the wavelength range of 600 nm to 800 nm. The green wavelength range corresponds to at least a part of the wavelength range of 500 nm to 600 nm. The blue wavelength range corresponds to at least a part of the wavelength range of 360 nm to 500 nm. Light in the red wavelength range is simply referred to as "red light," light in the green wavelength range is simply referred to as "green light," and light in the blue wavelength range is simply referred to as "blue light."

[0019] When a living body moves, the blue or green detection signal contains not only pulse information but also body movement information. In contrast, the red or infrared detection signal contains only a small amount of pulse information but a large amount of body movement information. Therefore, by comparing the blue or green detection signal with the red or infrared detection signal, the body movement information can be removed from the information contained in the blue or green detection signal, making it possible to obtain pulse information. The red or infrared detection signal is a detection signal for removing body movement information.

[0020] However, when detecting light from a living body through a general color filter containing a pigment or dye to obtain blue, green, and red detection signals, the following problem may arise. Fig. 2 is a graph showing the optical spectra of general color filters. In the example shown in Fig. 2, the general color filters are a red filter, a green filter, and a blue filter containing a dye. The dotted line, the dashed-dotted line, and the broken line shown in Fig. 2 represent the optical spectra of the red filter, the green filter, and the blue filter, respectively.

[0021] As shown in Figure 2, the blue, green, and red filters each have a broad peak in their corresponding wavelength range. The red filter has a relatively high transmittance not only in the red wavelength range but also in the wavelength range of 550 nm to 600 nm, as indicated by the hatching. Therefore, when light from a living body is detected through a typical red filter, the red detection signal may contain not only body movement information but also some pulse information. As a result, when comparing the blue or green detection signal with the red detection signal, not only the body movement information but also part of the pulse information may be removed from the information contained in the blue or green detection signal, which may result in inaccurate pulse information.

[0022] The device in Patent Document 1 uses a general red filter in the camera, so the red detection signal in the device in Patent Document 1 may contain not only body movement information but also some pulse information, which may result in inaccurate acquisition of pulse information.

[0023] The pulse sensor in Patent Document 2 detects reflected light without using a color filter. When the pulse sensor is used non-contact and not worn, the living body is irradiated with ambient light such as light from indoor lighting and sunlight. Therefore, when detecting infrared light from the living body, other light with a high absorption coefficient may also be detected. Therefore, with the pulse sensor in Patent Document 2, the infrared detection signal may contain not only body movement information but also pulse information to some extent, which may result in inaccurate pulse information acquisition.

[0024] The inventors have identified the above-mentioned problems and devised a bioinstrumentation device according to an embodiment of the present disclosure that can solve the problems. The bioinstrumentation device according to this embodiment is configured to make it difficult to detect at least a portion of light from a living body in the wavelength range of 550 nm to 600 nm. This reduces the possibility of bioinformation, such as pulse information, being mixed into a detection signal for removing body movement information. As a result, by comparing a detection signal containing not only bioinformation but also body movement information with a detection signal for removing body movement information, it becomes possible to effectively acquire bioinformation. The bioinstrumentation device according to an embodiment of the present disclosure is described below.

[0025] (Embodiment 1) [Biometric Measurement Device] Hereinafter, with reference to FIG. 3 , an exemplary configuration of a biometric measurement device according to embodiment 1 of the present disclosure will be described. In the following description, the biometric measurement device will also be simply referred to as a "measurement device." FIG. 3 is a diagram schematically illustrating the configuration of a measurement device according to exemplary embodiment 1 of the present disclosure. The measurement device 100A illustrated in FIG. 3 detects light from a living organism 10 to non-contactly acquire biometric information of the living organism 10. The light from the living organism 10 is generated, for example, when the living organism 10 is irradiated with ambient light. Although a human is illustrated as an example of the living organism 10, this example is not limiting. The living organism 10 may be, for example, an animal. The irradiated portion of the living organism 10 may be, for example, the face, arm, hand, or finger of the living organism 10. The living organism 10 may be stationary or moving.

[0026] As shown in FIG. 3 , the measurement device 100A includes a photodetector 20, a bandpass filter 30, and a processing device 40. The photodetector 20 includes a first filter 22a that transmits red light and a second filter 22b that transmits either green or blue light. The photodetector 20 further includes a first photodetector element 24a that detects light from the living body 10 via the first filter 22a and a second photodetector element 24b that detects light from the living body 10 via the second filter 22b. The first photodetector element 24a outputs a first signal based on the first light detected by the first photodetector element 24a. The second photodetector element 24b outputs a second signal based on the second light detected by the second photodetector element 24b. The second photodetector element 24b detects light that has passed through the second filter 22b and the bandpass filter 30 and has a wavelength of at least 550 nm or less. The first signal is a signal that corresponds to the intensity of the first light, and the second signal is a signal that corresponds to the intensity of the second light.

[0027] The bandpass filter 30 suppresses transmission of at least a portion of light from the living body 10 in the wavelength range of 550 nm to 600 nm, which is incident on the first filter 22a. FIG. 4 is a graph showing an example of the spectrum of the bandpass filter 30 and the absorption spectrum of oxygenated hemoglobin. The solid line in FIG. 4 represents the spectrum of the bandpass filter 30, and the dashed line in FIG. 4 represents the absorption spectrum of oxygenated hemoglobin. In the example shown in FIG. 4, the bandpass filter 30 has a spectral transmittance of nearly zero in the wavelength range of 550 nm to 600 nm, and a spectral transmittance of nearly 100% in other wavelength ranges. Therefore, transmission of light from the living body 10 in the wavelength range of 550 nm to 600 nm can be effectively suppressed. The light from the living body 10 passing through the bandpass filter 30 does not reflect the hatched portion of the absorption spectrum of oxygenated hemoglobin.

[0028] FIG. 5 is a graph showing an example of the optical spectrum of a configuration combining the bandpass filter 30 and a general color filter. As shown in FIG. 5, in the configuration combining the bandpass filter 30 and a general color filter, the spectral transmittance is nearly zero in the wavelength range from 550 nm to 600 nm. Therefore, when the living body 10 moves, the second signal contains not only biological information but also body movement information, while the first signal contains little biological information but a lot of body movement information. In this way, the bandpass filter 30 can effectively prevent biological information from being mixed into the first signal.

[0029] FIG. 6 is a diagram schematically illustrating an example of time-series data of the first and second signals and an example of biometric information. The vertical direction in FIG. 6 represents signal strength, and the horizontal direction in FIG. 6 represents time. Pulse information is illustrated as an example of the biometric information shown in FIG. 6. When the living body 10 moves during measurement, as shown in FIG. 6, the time-series data of the second signal changes while continuously oscillating to reflect the pulse information, and also shifts significantly at certain times to reflect the body movement information. In contrast, the time-series data of the first signal shifts significantly at certain times to reflect the body movement information, but due to the presence of the band-pass filter 30, it does not reflect the pulse information and barely oscillates. As a result, by comparing the first and second signals, the processing device 40 can remove the body movement information from the information contained in the second signal while preventing a portion of the pulse information from being removed from the information contained in the second signal, thereby enabling more accurate acquisition of pulse information.

[0030] From the above, the measurement device 100A according to the first embodiment can acquire biometric information of the living body 10 more accurately than a configuration in which the band-pass filter 30 is removed from the measurement device 100A. This leads to more effective acquisition of biometric information of the living body 10.

[0031] The configurations of the photodetector 20, the bandpass filter 30, and the processing device 40 will be described in detail below.

[0032] <Photodetector 20> As shown in Fig. 3, the photodetector 20 includes at least one first filter 22a and at least one second filter 22b. The first filter 22a and the second filter 22b are as described above. The photodetector 20 may further include at least one third filter that transmits the other of the green and blue light. The number of first filters 22a may be one or more. The same applies to the number of second filters 22b and the number of third filters.

[0033] For the following reasons, the first filter 22a may be designed to transmit light with a wavelength of 690 nm with a high spectral transmittance. A high spectral transmittance may be, for example, 60% or more, 80% or more, 90% or more, or 95% or more. As shown in FIG. 4 , the absorption coefficient of oxygenated hemoglobin is smallest at a wavelength of 690 nm in the wavelength range of 300 nm to 900 nm. Therefore, light from the living body 10 with a wavelength of 690 nm contains little biological information. Therefore, by designing the first filter 22a as described above, the amount of biological information contained in the first signal can be effectively reduced.

[0034] The first filter 22 a, the second filter 22 b, and the third filter may be the same as the general color filters described above, which are readily available, low-cost, and suitable for mass production.

[0035] As shown in Figure 2, the spectral spectrum of a typical red filter has a broad peak in the wavelength range of 550 nm to 800 nm. The peak wavelength is within the wavelength range of 550 nm to 800 nm. The spectral transmittance at the peak wavelength can be the maximum spectral transmittance in the wavelength range of visible light. The spectral spectrum of a typical red filter has a spectral transmittance of 30% or more in at least a portion of the wavelength range of 550 nm to 600 nm. The spectral spectrum of a typical red filter also has a spectral transmittance of 20% or less in the wavelength range of 500 nm or less within the wavelength range of visible light.

[0036] The optical spectrum of a typical green filter has a broad peak in the wavelength range of 450 nm to 650 nm, inclusive. The peak wavelength is in the wavelength range of 450 nm to 650 nm, inclusive. The optical spectrum of a typical blue filter has a broad peak in the wavelength range of 360 nm to 550 nm, inclusive. The peak wavelength is in the wavelength range of 360 nm to 550 nm, inclusive.

[0037] The light detection device 20 includes at least one first light detection element 24a and at least one second light detection element 24b. The first light detection element 24a and the second light detection element 24b are as described above. The light detection device 20 may further include at least one third light detection element that detects light from the living body 10 via a third filter. The third light detection element outputs a third signal based on the third light detected by the third light detection element. The third signal is a signal corresponding to the intensity of the third light.

[0038] When the first filters 22a and the first photodetecting elements 24a have a one-to-one correspondence, the number of first photodetecting elements 24a is equal to the number of first filters 22a. Similarly, the number of second photodetecting elements 24b is equal to the number of second filters 22b. The number of third photodetecting elements is equal to the number of third filters.

[0039] Alternatively, when the first filter 22a overlaps two or more first photodetecting elements 24a when viewed from the direction of incidence of light from the living body 10, the number of first photodetecting elements 24a may be greater than the number of first filters 22a. Similarly, the number of second photodetecting elements 24b may be greater than the number of second filters 22b. The number of third photodetecting elements may be greater than the number of third filters.

[0040] The light detection device 20 may be, for example, a color camera equipped with a plurality of common color filters and an image sensor. In this case, the light detection device 20 can acquire a color image of the living body 10. The image sensor includes a plurality of light detection elements arranged two-dimensionally. The image sensor may be a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) sensor. Each of the plurality of color filters may be provided directly on a corresponding one of the plurality of light detection elements, or may be provided indirectly via another member.

[0041] FIG. 7 is a diagram schematically illustrating an example of the arrangement of color filters in the photodetector 20. In FIG. 7, "R," "G," and "B" represent red, green, and blue filters, respectively. In the example illustrated in FIG. 7, the first filter 22a is a red filter, the second filter 22b is a blue filter, and the third filter 22c is a green filter. In the example illustrated in FIG. 7, the arrangement of the color filters is a so-called Bayer array. The Bayer array has multiple units arranged two-dimensionally. Each unit includes filters arranged in two rows and two columns. In each unit, two green filters are arranged in the diagonal components, and a red filter and a blue filter are arranged in the off-diagonal components. Alternatively, in each unit, two red filters may be arranged in the diagonal components, and a green filter and a blue filter may be arranged in the off-diagonal components. In each unit, two blue filters may be arranged in the diagonal components, and a green filter and a red filter may be arranged in the off-diagonal components. The arrangement of the plurality of color filters is not limited to the Bayer arrangement, but may be a stripe arrangement, a delta arrangement, a mosaic arrangement, or a pentile arrangement. In the photodetector 20, an infrared filter may be used instead of the red filter.

[0042] <Bandpass Filter 30> The bandpass filter 30 prevents at least a portion of the light from the living body 10 incident on the first filter 22a in the wavelength range of 550 nm to 600 nm from passing through. When a typical red filter is used as the first filter 22a, the first filter 22a transmits not only red light but also light in the wavelength range of 550 nm to 600 nm, as shown in FIG. 2 . This may result in biological information being mixed into the first signal in a configuration in which the bandpass filter 30 is removed from the measurement device 100A. In contrast, the measurement device 100A uses the bandpass filter 30 to reduce this possibility. The first filter 22a, the bandpass filter 30, and the first photodetector element 24a may be arranged in this order so that light from the living body 10 is incident from the first filter 22a toward the first photodetector element 24a. That is, the bandpass filter 30 may be arranged between the first filter 22a and the first photodetector element 24a.

[0043] The wavelength range in which light transmission through the bandpass filter 30 is suppressed may be the entire wavelength range of 550 nm to 600 nm or less, or may be a part of the wavelength range. For example, the bandpass filter 30 may suppress transmission of light in the wavelength range of 570 nm to 600 nm within the wavelength range of 550 nm to 600 nm, while transmitting light in other wavelength ranges.

[0044] In this specification, "suppressing transmission of at least a portion of light in the wavelength range of 550 nm to 600 nm" means that the spectral transmittance in at least a portion of the wavelength range of 550 nm to 600 nm is 20% or less. The spectral transmittance may be 10% or less, 5% or less, or 1% or less. The closer the spectral transmittance is to zero, the more accurately biological information can be acquired based on the first signal and the second signal.

[0045] In the example shown in Fig. 4, the spectral transmittance of the bandpass filter 30 is approximately 100% in the remaining wavelength range of visible light, excluding the wavelength range where light transmission is suppressed. However, the spectral transmittance of the bandpass filter 30 in the remaining wavelength range does not need to be approximately 100%. The spectral transmittance may be, for example, 60% or more, 80% or more, 90% or more, or 95% or more. The higher the spectral transmittance, the more body movement information the first signal can contain, and the more biological information the second signal can contain.

[0046] When viewed from the direction of incidence of light from the living body 10, the bandpass filter 30 is arranged so as to overlap the first filter 22a. On the other hand, the bandpass filter 30 may or may not overlap the second filter 22b and the third filter 22c. However, if the photodetector 20 is a color camera, not only the first filters 22a but also the second filters 22b and the third filters 22c are arranged two-dimensionally. Therefore, it is easier to arrange the bandpass filter 30 so that it overlaps the entire photodetector 20. Furthermore, by separately preparing the color filter and the bandpass filter 30, a color camera, which is easy to mass-produce, can be used as the photodetector 20, thereby reducing the manufacturing cost of the measurement device 100A.

[0047] When the bandpass filter 30 overlaps the second filter 22b and the third filter 22c, the amount of light incident on the second and third photodetector elements is reduced, at least in part, in the wavelength range of 550 nm to 600 nm. Even in this case, the second and third signals contain a reduced amount of biological information, but still contain sufficient biological information. This is because, as shown in FIG. 5 , in a configuration in which the bandpass filter 30 and a green filter are combined, the spectral transmittance is sufficiently high in the wavelength range of 500 nm to 550 nm. Similarly, in a configuration in which the bandpass filter 30 and a blue filter are combined, the spectral transmittance is sufficiently high in the wavelength range of 400 nm to 500 nm. As shown in FIG. 4 , the absorption coefficient of oxygenated hemoglobin is sufficiently high in these wavelength ranges.

[0048] The bandpass filter 30 may be, for example, an interference filter including a dielectric multilayer film. An interference filter including a dielectric multilayer film can achieve a steep spectral change. Therefore, it can effectively suppress transmission of at least a portion of light in the wavelength range of 550 nm to 600 nm inclusive of the visible light wavelength range, and can effectively transmit light in the remaining wavelength range.

[0049] Alternatively, the bandpass filter 30 may be a filter containing, for example, a pigment or a dye. Such a filter has the advantage that it does not depend on the angle of incidence of incident light, unlike an interference filter containing a dielectric multilayer film.

[0050] 3, the processing device 40 includes a control circuit 42, a signal processing circuit 44, and a memory 46. The control circuit 42 controls the processing operation of the signal processing circuit 44.

[0051] The signal processing circuit 44 generates biometric information of the living body 10 based on the first light and the second light, more specifically, based on the first signal and the second signal. A method for generating biometric information based on the first signal and the second signal will be described later. When acquiring time-series data of the first signal, the second signal, and the third signal, the signal processing circuit 44 may adjust the exposure time per frame to increase the intensities of the first signal, the second signal, and the third signal.

[0052] The control circuit 42 may be, for example, a combination of a processor and a memory, or an integrated circuit such as a microcontroller incorporating a processor and a memory. The control circuit 42 causes the signal processing circuit 44 to perform signal processing, for example, by the processor executing a computer program stored in the memory 46.

[0053] The signal processing circuit 44 can be realized by, for example, a digital signal processor (DSP), a programmable logic device (PLD) such as a field programmable gate array (FPGA), or a combination of a central processing unit (CPU) or a graphics processing unit (GPU) and a computer program. The signal processing circuit 44 performs signal processing by having the processor execute the computer program recorded in the memory 46.

[0054] The control circuit 42 and the signal processing circuit 44 may be integrated into a single circuit or may be separate individual circuits. At least one of the control circuit 42, the signal processing circuit 44, and the memory 46 may be a component of an external device, such as a server, provided in a remote location. In this case, the external device, such as the server, transmits and receives data to and from the remaining components via wireless or wired communication.

[0055] In this specification, the control circuit 42 and the signal processing circuit 44 are also collectively referred to as a “processing circuit.” The operations of the control circuit 42 and the signal processing circuit 44 may be treated as operations of the processing circuit.

[0056] <Other Components> In addition to the components described above, the measurement apparatus 100A may further include, for example, an optical system arranged in front of the band-pass filter 30. The optical system may include, for example, a large-aperture lens having an F-number of 1 or less. Such a large-aperture lens can improve the sensitivity of light detection by the light detection device 20.

[0057] [Biometric Information Generation Method] Hereinafter, a method for generating biometric information based on the first signal and the second signal will be described.

[0058] <Difference> The signal processing circuit 44 can generate biometric information based on the difference between the change in intensity of the first signal over time and the change in intensity of the second signal over time. More specifically, the signal processing circuit 44 acquires the biometric information contained in the second signal by subtracting data obtained by multiplying the time-series data of the first signal by an appropriate coefficient from the time-series data of the second signal. The coefficient can be appropriately determined, for example, during calibration before shipping the measurement device 100A.

[0059] The method of generating biological information from the difference can reduce the load of calculation processing on the signal processing circuit 44.

[0060] <Independent Component Analysis or Principal Component Analysis> The signal processing circuit 44 may apply independent component analysis or principal component analysis to the time series data of the first signal and the time series data of the second signal. By using the independent component analysis or principal component analysis, it is possible to separate biological information and body movement information from these two time series data.

[0061] Alternatively, the signal processing circuit 44 may apply independent component analysis or principal component analysis to the time-series data of the third signal in addition to the time-series data of the first and second signals. As a result, biological information, body movement information, and noise information can be separated from these three time-series data. The noise information may be, for example, information about Schottky noise.

[0062] The method of generating biometric information using independent component analysis or principal component analysis can acquire biometric information more accurately than the method of generating biometric information using differential analysis.

[0063] <Machine Learning> The signal processing circuit 44 may acquire biological information from the time-series data of the first signal and the time-series data of the second signal by machine learning.

[0064] The signal processing circuit 44 acquires the first signal and the second signal using the measurement device 100A, and simultaneously acquires biological information using another measurement device. The signal processing circuit 44 further uses the biological information acquired by the other measurement device as correct answer data to create a regression model that predicts pulse information from the first signal and the second signal through machine learning. The signal processing circuit 44 acquires biological information from the time series data of the first signal and the time series data of the second signal based on the regression model created in this manner.

[0065] As the machine learning, logistic regression or support vector machine may be used, or deep learning, which is a type of machine learning, may be used. Time series data of biological information may be predicted using LSTM (Long Short-Term Memory), which is used for predicting time series data.

[0066] When the biological information is pulse information, for example, an electrocardiogram sensor can be used as another measurement device for acquiring correct data. When measuring a photoplethysmogram from a fingertip using the photoplethysmography method, the fingertip remains stationary so that the photoplethysmogram does not include shifts due to body movement. Because the signal from the photoplethysmogram is similar to the signal acquired by the measurement device 100A, the accuracy of regression can be improved.

[0067] In the method for generating biometric information using machine learning, unlike the example shown in FIG. 6 , the tendency of body movement information to overlap in the first signal may differ from the tendency of body movement information to overlap in the second signal. The difference in the tendency of overlap between the two may occur, for example, in an environment where the illuminance distribution on the living body 10 is different for the red light used to acquire the first signal and one of the green and blue lights used to acquire the second signal. Learning data may be collected by acquiring biometric information in such an environment. Using the learning data collected in this manner, a regression model reflecting the difference in the tendency of overlap between the two can be created. Therefore, even if the tendency of overlap between the two is different, it is possible to remove body movement information from the information included in the second signal while preventing a portion of the biometric information from being removed from the information included in the second signal, thereby enabling more accurate acquisition of biometric information.

[0068] [Type of Biological Information] As described above, the biological information may be, for example, pulse information. Alternatively, the biological information may be blood flow information. Changes in blood flow cause a change in the color of the irradiated portion of the living body 10. The blood flow information can be obtained from the change in color over time. The color can be known based on the first signal, the second signal, and the third signal. If the irradiated portion of the living body 10 is the face, the blood flow information is facial blood flow information.

[0069] Alternatively, the biological information may be oxygen saturation information. If the concentrations of oxygenated hemoglobin and deoxygenated hemoglobin in blood are designated as a first concentration and a second concentration, respectively, the oxygen saturation can be calculated by dividing the first concentration by (first concentration + second concentration). The absorption spectrum of deoxygenated hemoglobin is different from the absorption spectrum of oxygenated hemoglobin shown in FIG. 4 .

[0070] The oxygen saturation can be calculated based on the first signal and the second signal, for example, as follows: By solving the simultaneous equations represented by the following equations (1) and (2), the oxygen saturation of the blood can be calculated by calculating the oxygenated hemoglobin (HbO ２ The amount of change from the initial value of each of the concentrations of oxygenated hemoglobin (Hb) and deoxygenated hemoglobin (Hb) can be seen.

[0071] ΔHbO ２ and ΔHb are the HbO in the blood, respectively. ２ and the change in Hb concentration from the initial value. １ ＯＸＹ and ε １ ｄｅＯＸＹ and HbO for red light to obtain the first signal, respectively. ２ and the molar extinction coefficient of Hb. ２ ＯＸＹ and ε ２ ｄｅＯＸＹ are the HbO concentrations for green and blue light, respectively, for obtaining the second signal. ２ and the molar extinction coefficient of Hb. １ ｉｎｉ and I ２ ｎｏｗ and I represent the intensities of the first signal at the initial time point and the measurement time point, respectively.２ ｉｎｉ and I ２ ｎｏｗ and represent the intensities of the second signal at the initial time point and the measurement time point, respectively.

[0072] ε ２ ＯＸＹ and ε ２ ｄｅＯＸＹ Although the difference between １ ＯＸＹ and ε １ ｄｅＯＸＹ Since the values ​​of ΔHbO and ΔHbO are relatively different, the above simultaneous equations can be solved. ２ If ΔHb and ΔHb are known, the oxygen saturation can be calculated from a predetermined equation.

[0073] Alternatively, the biological information may be blood pressure information. If pulse information is known, the pulse wave propagation time can be determined from the waveform of the pulse wave. If the systolic blood pressure is P and the pulse wave propagation time is ΔT, the systolic blood pressure P can be determined from the relationship P = a × ln ΔT + b. The coefficients a and b can be appropriately determined, for example, during calibration before shipping the measurement device 100A.

[0074] [Face Tracking] When the light detection device 20 is a color camera, the face of the living body 10 can be tracked as follows. The RGB (Red, Green, Blue) color space obtained by the first signal, the second signal, and the third signal is converted into a color space including hue. The color space including hue can be, for example, an HSV (Hue, Saturation, Value) color space, an HSL (Hue, Saturation, Luminance) color space, or an HSI (Hue, Saturation, Intensity) color space.

[0075] The signal processing circuit 44 generates hue information of the living body 10 based on the third light in addition to the first and second lights, more specifically, based on the third signal in addition to the first and second signals. The signal processing circuit 44 tracks the face of the living body 10 based on the hue information. "Tracking the face" means identifying the position of the face, more specifically, identifying the photodetector element corresponding to the position of the face among multiple photodetectors included in the color camera. "Based on the hue information" means comparing the hue with a preset hue condition, more specifically, setting a condition that determines that the hue is human skin if it is within a predetermined range, and checking whether the acquired hue meets the condition.

[0076] A more specific configuration of the photodetector 20 and a more specific operation of the signal processing circuit 44 are as follows.

[0077] The photodetector 20 includes a plurality of first filters 22a, a plurality of second filters 22b, and a plurality of third filters. The plurality of first filters 22a have the same configuration. The same applies to the plurality of second filters 22b and the plurality of third filters. The photodetector 20 further includes a plurality of first photodetector elements 24a, a plurality of second photodetector elements 24b, and a plurality of third photodetector elements. The plurality of first photodetector elements 24a have the same configuration. The same applies to the plurality of second photodetector elements 24b and the plurality of third photodetector elements.

[0078] The signal processing circuit 44 generates hue information of the living body 10 based on the light detected by each of the plurality of first photodetection elements 24 a, the light detected by each of the plurality of second photodetection elements 24 b, and the light detected by each of the plurality of third photodetection elements. Based on the hue information, the signal processing circuit 44 determines the first photodetection elements 24 a, the second photodetection elements 24 b, and the third photodetection elements that correspond to the position of the face, from among the plurality of first photodetection elements 24 a, the plurality of second photodetection elements 24 b, and the plurality of third photodetection elements included in the photodetection device 20.

[0079] Therefore, even if a person moves during measurement, it is possible to determine which part of the image captured by the color camera contains the face. First and second signals can be acquired from the part of the image containing the face, and biometric information can be acquired based on these first and second signals. Furthermore, the bandpass filter 30 reduces the effect of partial overlap between the spectral spectrum of the red filter and the spectral spectrum of one of the green and blue filters, thereby improving the accuracy of the hue information. Tracking is not limited to faces; skin, i.e., the position of the skin, may also be identified.

[0080] From the above, according to the measurement device 100A of the first embodiment, the second signal includes not only biological information but also body movement information, whereas the first signal includes a large amount of body movement information and only a small amount of biological information due to the presence of the band-pass filter 30. As a result, biological information of the living body 10 can be effectively acquired based on the first and second signals.

[0081] (Embodiment 2) Hereinafter, an exemplary configuration of a measurement device according to embodiment 2 of the present disclosure will be described with reference to Fig. 8. Fig. 8 is a diagram schematically illustrating the configuration of a measurement device according to exemplary embodiment 2 of the present disclosure. Unlike measurement device 100A shown in Fig. 3, measurement device 100B shown in Fig. 8 further includes a light source 50 that emits light for irradiating living organism 10. Control circuit 42 causes light source 50 to emit light for irradiating living organism 10 constantly or intermittently. The light source 50 makes it possible to acquire biometric information of living organism 10 even in the absence of ambient light.

[0082] The light source 50 emits red light and one of green and blue light for illuminating the living body 10. The light source 50 may further emit the other of green and blue light for illuminating the living body 10. The red light is useful for acquiring a first signal, and the one of green and blue light is useful for acquiring a second signal. The other of green and blue light is useful for acquiring a third signal.

[0083] The measurement device 100B may further include a diffuser plate that diffuses the light emitted from the light source 50. The diffused light can be used to uniformly illuminate the living body 10, making it possible to evaluate biological information using the same criteria in any area of ​​the illuminated portion of the living body 10. The any area of ​​the illuminated portion of the living body 10 can be, for example, the left or right area of ​​the forehead.

[0084] <Configuration Example 1 of Light Source 50> Fig. 9A is a diagram schematically illustrating Configuration Example 1 of the light source 50. As shown in Fig. 9A, the light source 50 includes, for example, a wavelength conversion element 52 and a light-emitting element 54 that emits excitation light that excites the wavelength conversion element 52. The white arrows in Fig. 9A represent the excitation light. The light-emitting element 54 may be, for example, a laser diode (LD) or a light-emitting diode (LED).

[0085] When the light-emitting element 54 emits blue light, the wavelength conversion element 52 may include, for example, a phosphor that absorbs blue light and emits yellow light. The yellow light includes red light and green light. The red light included in the yellow light is useful for obtaining the first signal. The blue light is useful for obtaining one of the second signal and the third signal, and the green light included in the yellow light is useful for obtaining the other of the second signal and the third signal.

[0086] A portion of the blue light emitted from the light emitting element 54 is converted to yellow light by the phosphor, and the remaining portion passes through the wavelength conversion element 52 without being converted. As a result, the light source 50 emits white light that is a mixture of yellow light and blue light. The general color rendering index Ra of this light source 50 may be, for example, 80 or more. The closer the general color rendering index Ra is to 100, the closer the color of an object illuminated by the light emitted from the light source 50 will be to the color of the object illuminated by sunlight.

[0087] Since ambient light such as light from indoor lighting and sunlight is white light, the white light emitted from the light source 50 can reduce the psychological burden on the living body 10 during measurement. Furthermore, the closer the general color rendering index Ra is to 100, the more light with a wavelength of 690 nm the white light contains. Therefore, when the first filter 22a is designed to transmit light with a wavelength of 690 nm with a high spectral transmittance as described above, the signal-to-noise ratio of the first signal can be improved.

[0088] Alternatively, when the light-emitting element 54 emits blue light, the wavelength conversion element 52 may include, for example, the following first and second phosphors: the first phosphor absorbs blue light and emits red light, and the second phosphor absorbs blue light and emits green light.

[0089] A portion of the blue light emitted from the light emitting element 54 is converted to red light by the first phosphor, another portion is converted to green light by the second phosphor, and the remaining portion passes through the wavelength conversion element 52 without being converted. As a result, the light source 50 emits white light that is a mixture of red light, green light, and blue light. The general color rendering index Ra of this light source 50 may be, for example, 90 or higher.

[0090] FIG. 9B is a graph showing an example of the emission spectrum of light emitted from the light source 50. In the example shown in FIG. 9B, the light-emitting element 54 emits blue light, and the wavelength conversion element 52 includes the first phosphor and the second phosphor. As shown in FIG. 9B, the emission spectrum has the largest peak in the blue wavelength range. The emission spectrum also has a peak in the green wavelength range and a peak in the red wavelength range. Since the emission spectrum has peaks in the wavelength ranges of each of the three colors, the general color rendering index Ra is high. Note that if there is no need to acquire a third signal, the wavelength conversion element 52 does not necessarily need to include the second phosphor that absorbs blue light and emits green light.

[0091] Alternatively, when the light-emitting element 54 emits ultraviolet light, the wavelength conversion element 52 may include, for example, the following first, second, and third phosphors. The first phosphor absorbs ultraviolet light and emits red light. The second phosphor absorbs ultraviolet light and emits one of green and blue light. The third phosphor absorbs ultraviolet light and emits the other of green and blue light.

[0092] A portion of the ultraviolet light emitted from the light-emitting element 54 is converted into red light by the first phosphor, another portion is converted into one of green and blue light by the second phosphor, and still another portion is converted into the other of green and blue light by the third phosphor. When the wavelength conversion element 52 includes the first phosphor, the second phosphor, and the third phosphor, the light source 50 emits white light that is a mixture of red light, green light, and blue light. The general color rendering index Ra of this light source 50 may be, for example, 95 or greater. Note that if there is no need to acquire a third signal, the wavelength conversion element 52 does not necessarily need to include the third phosphor that absorbs ultraviolet light and emits the other of green and blue light.

[0093] 9A, the light source 50 equipped with the wavelength conversion element 52 can emit red light and one of green and blue light from the same location of the wavelength conversion element 52. Since the living body 10 is irradiated with the red light and one of green and blue light emitted from the same location, the first signal and the second signal acquired as a result of the irradiation are completely synchronized with the body movement information included in the second signal. Therefore, the biological information of the living body 10 can be acquired more effectively based on the first signal and the second signal.

[0094] <Configuration Example 2 of Light Source 50> Fig. 10A is a diagram schematically illustrating Configuration Example 2 of the light source 50. As shown in Fig. 10A, the light source 50 may include, for example, a first light-emitting element 54a, a second light-emitting element 54b, and a third light-emitting element 54c. The first light-emitting element 54a emits red light. The second light-emitting element 54b emits one of green and blue light. The third light-emitting element 54c emits the other of green and blue light. The first light-emitting element 54a, the second light-emitting element 54b, and the third light-emitting element 54c may be, for example, an LD or an LED. Note that if there is no need to acquire a third signal, the light source 50 does not necessarily have to include the third light-emitting element 54c.

[0095] The first light-emitting element 54a, the second light-emitting element 54b, and the third light-emitting element 54c can be arranged, for example, so that the center-to-center distance between any two light-emitting elements is 10 mm or less. When the distance from the light source 50 to the living body 10 is 30 cm, if the center-to-center distance between any two light-emitting elements is greater than 10 mm, the signal strength error will be greater than 1% due to the difference in illuminance caused by the angle of incidence of the light emitted from the two light-emitting elements and incident on the living body 10. This signal strength error is comparable to or greater than the amount of change in signal strength due to pulse. If the center-to-center distance between any two light-emitting elements is 10 mm or less, the signal strength error can be reduced.

[0096] Fig. 10B is a graph showing another example of the emission spectrum of light emitted from the light source 50. In the example shown in Fig. 10B, the light source 50 includes the first light-emitting element 54a, the second light-emitting element 54b, and the third light-emitting element 54c. These light-emitting elements are LEDs, which are lower in cost than LDs.

[0097] When all the light-emitting elements are LEDs, the emission spectrum of each color of light is narrowed to a certain extent, and thus, compared to when a wavelength conversion element 52 is used as shown in FIG. 9A , it is possible to reduce light of wavelengths unnecessary for acquiring biological information. Therefore, it is possible to reduce glare. Although the emission spectrum of red light overlaps with the emission spectrum of green light in the wavelength range of 550 nm or more and 600 nm or less, the influence of this overlap can be reduced by the bandpass filter 30. The emission spectrum shown in FIG. 10B can also be achieved by the aforementioned light source 50, which emits red, green, and blue light by exciting three phosphors with ultraviolet light.

[0098] When all the light-emitting elements are LDs, the emission spectrum of each light is sufficiently narrow, so compared to when all the light-emitting elements are LEDs, it is possible to further reduce light of wavelengths unnecessary for acquiring biological information. Therefore, it is possible to further reduce glare. However, when using LDs, for eye safety, the laser light intensity is designed to meet Class 1 in accordance with the safety standard for laser devices set forth in "JIS C 6802."

[0099] When an LD is used, the emission spectrum of red light does not overlap with the emission spectrum of green light in the wavelength range of 550 nm to 600 nm, but when the measurement device 100A is used in a non-contact manner, the light from the living body 10 may also contain light in the wavelength range of 550 nm to 600 nm due to ambient light. Even in this case, the presence of the bandpass filter 30 makes it possible to prevent at least a portion of the light in that wavelength range due to ambient light from being mixed into the first signal.

[0100] When using an LD or LED, the peak intensities of the red light, green light, and blue light do not need to be the same. Figure 10C is a graph showing yet another example of the emission spectrum of light emitted from light source 50. In the example shown in Figure 10C, light source 50 includes first light-emitting element 54a, second light-emitting element 54b, and third light-emitting element 54c. These light-emitting elements are LEDs. As shown in Figure 10C, the peak intensities of the green and blue light are lower than the peak intensity of the red light.

[0101] 10B , when the peak intensities of red light, green light, and blue light are the same, the following problem may occur: Because the bandpass filter 30 prevents at least a portion of light in the wavelength range of 550 nm to 600 nm from passing through, the intensity of the first signal may be lower than the intensity of the second signal and lower than the intensity of the third signal. While the intensity of the first signal can be increased by increasing the exposure time, the intensity of the second signal and the intensity of the third signal may be saturated.

[0102] 10C , the intensity of the first signal can be increased and the possibility of the intensity of the second signal and the intensity of the third signal being saturated can be reduced by extending the exposure time. When the peak intensity of each of the green and blue light is half or less of the peak intensity of the red light, the possibility can be effectively reduced.

[0103] The intensities of the light emitted from the first light-emitting element 54 a, the second light-emitting element 54 b, and the third light-emitting element 54 c may be adjusted so that the peak intensities of the red, green, and blue light satisfy the magnitude relationship shown in Fig. 10C. Alternatively, the peak intensities of the green light and the blue light may be reduced by placing a filter with low spectral transmittance for green light and blue light in front of the light source 50.

[0104] In the above-described first configuration example of the light source 50, the peak intensity of each of the green and blue light may be made lower than the peak intensity of the red light by adjusting the amount of phosphor contained in the wavelength conversion element 52. Alternatively, in the above-described first configuration example of the light source 50, the peak intensity of the green light and the peak intensity of the blue light may be reduced by placing a filter having low spectral transmittance for the green light and the blue light in front of the light source 50.

[0105] From the above, the measurement device 100B according to embodiment 2 can generate more accurate biological information of the living organism 10 based on the first signal and the second signal, similar to the measurement device 100A according to embodiment 1. Furthermore, the measurement device 100B according to embodiment 2 can acquire biological information even in the absence of ambient light by irradiating the living organism 10 with light emitted from the light source 50.

[0106] (Third Embodiment) Hereinafter, an example configuration of a measurement device according to a third embodiment of the present disclosure will be described with reference to Fig. 11. Fig. 11 is a diagram schematically illustrating the configuration of a measurement device according to an exemplary third embodiment of the present disclosure. Unlike the measurement device 100A shown in Fig. 3, the measurement device 100C shown in Fig. 11 does not include the bandpass filter 30, and includes a photodetector 20-1 instead of the photodetector 20 shown in Fig. 3. The measurement device 100C may further include a light source 50 shown in Fig. 8.

[0107] The photodetector 20-1 includes a first filter 23a that transmits red light and a second filter 23b that transmits either green or blue light. However, unlike the first filter 22a and the second filter 22b shown in FIG. 3, the first filter 23a and the second filter 23b are not typical color filters but may be, for example, interference filters including a dielectric multilayer film. The first filter 23a transmits red light while suppressing the transmission of at least a portion of light in the wavelength range of 550 nm to 600 nm. Therefore, it is possible to suppress the inclusion of biological information in the first signal.

[0108] The configuration of the photodetector 20-1 will be described in detail below.

[0109] <Photodetecting Device 20-1> The photodetecting device 20-1 includes at least one first filter 23a and at least one second filter 23b. The first filter 23a and the second filter 23b are as described above. The photodetecting device 20-1 may further include at least one third filter that transmits the other of the green and blue light. Like the first filter 23a and the second filter 23b, the third filter may be, for example, an interference filter including a dielectric multilayer film. The number of first filters 23a may be one or more. The same applies to the number of second filters 23b and the number of third filters. An example of the arrangement of the first filter 23a, the second filter 23b, and the third filter is as described in the measurement device 100A according to embodiment 1.

[0110] The photodetector 20-1 includes at least one first photodetector element 24a that detects light from the living organism 10 via a first filter 23a, and at least one second photodetector element 24b that detects light from the living organism 10 via a second filter 23b. The photodetector 20 may further include at least one third photodetector element that detects light from the living organism 10 via a third filter. The first photodetector element 24a, the second photodetector element 24b, and the third photodetector element are as described in the measurement device 100A according to the first embodiment.

[0111] The first filter 22 a, the second filter 22 b, and the third filter, which are interference filters including a dielectric multilayer film, may be stacked directly on the first photodetecting element 24 a, the second photodetecting element 24 b, and the third photodetecting element, respectively. That is, the photodetecting device 20-1 includes a plurality of filters and a plurality of photodetecting elements that are integrally formed.

[0112] 12A to 12C are graphs showing examples of the optical spectra of the first filter 23 a, the second filter 23 b, and the third filter, respectively. In the examples shown in Fig. 12A to 12C, the first filter 23 a is a red filter, the second filter 23 b is a green filter, and the third filter is a blue filter.

[0113] 12A , the first filter 23 a has a high spectral transmittance in the red wavelength range of the visible light wavelength region and a spectral transmittance of approximately zero in the remaining wavelength range, including the wavelength range of 550 nm to 600 nm. The high spectral transmittance may be, for example, 60% or more, 80% or more, 90% or more, or 95% or more. In the example shown in FIG. 12A , the red wavelength range is 600 nm to 700 nm.

[0114] 12B, the second filter 23b has a high spectral transmittance in the green wavelength range of the visible light, and has a spectral transmittance of almost zero in the remaining wavelength range. In the example shown in FIG. 12B, the green wavelength range is 500 nm or more and 600 nm or less.

[0115] 12C , the third filter has a high spectral transmittance in the blue wavelength range of the visible light wavelength range and a spectral transmittance of almost zero in the remaining wavelength range. In the example shown in FIG. 12C , the blue wavelength range is from 400 nm to 500 nm.

[0116] Because the interference filters include dielectric multilayer films, the spectra of the first filter 23 a, the second filter 23 b, and the third filter change sharply. Therefore, the spectrum of the first filter 23 a barely overlaps with the spectrum of the second filter 23 b and the spectrum of the second filter. Similarly, the spectrum of the second filter 23 b barely overlaps with the spectrum of the third filter. Therefore, the first signal and the second signal hardly contain information about light in the same wavelength range. The same is true for the first signal and the third signal, and the same is true for the second signal and the third signal.

[0117] From the above, according to the measuring device 100C of embodiment 3, it is possible to effectively acquire biological information of the living body 10 based on the first signal and the second signal, similar to the measuring device 100A of embodiment 1, without using the bandpass filter 30.

[0118] 13A to 14C , modified examples of the bandpass filter 30 included in the measurement device 100A according to embodiment 1 and the measurement device 100B according to embodiment 2 will be described. The bandpass filter 30 included in the measurement device 100A and the measurement device 100B suppresses transmission of at least a portion of light in the wavelength range of 550 nm to 600 nm inclusive of the wavelength range of visible light, and transmits light in the remaining wavelength range. The bandpass filter 30 may also suppress transmission of light in a portion of the remaining wavelength range.

[0119] 13A to 13C are diagrams schematically illustrating three other examples of the spectral spectrum of the bandpass filter 30. In the example shown in FIG. 13A , the bandpass filter 30 has a high spectral transmittance in the red wavelength range and a high spectral transmittance in the blue wavelength range within the visible light wavelength range. The maximum spectral transmittance in the blue wavelength range is approximately equal to the maximum spectral transmittance in the red wavelength range. The spectral transmittance in the remaining wavelength range, including the wavelength range from 550 nm to 600 nm, is approximately zero. In the example shown in FIG. 13A , the red wavelength range is from 640 nm to 710 nm, and the blue wavelength range is from 410 nm to 460 nm. This bandpass filter 30 is advantageous for detecting red light to acquire a first signal and detecting blue light to acquire a second signal.

[0120] In the example shown in FIG. 13B , the bandpass filter 30 has a high spectral transmittance in the red wavelength range and a high spectral transmittance in the green wavelength range within the visible light wavelength range. The maximum spectral transmittance in the green wavelength range is approximately equal to the maximum spectral transmittance in the red wavelength range. The spectral transmittance in the remaining wavelength range, including the wavelength range of 550 nm to 600 nm, is approximately zero. In the example shown in FIG. 13B , the red wavelength range is 640 nm to 710 nm, and the green wavelength range is 500 nm to 550 nm. This bandpass filter 30 is advantageous for detecting red light to acquire the first signal and detecting green light to acquire the second signal.

[0121] In the example shown in FIG. 13C , the bandpass filter 30 has a high spectral transmittance in the red wavelength range, a high spectral transmittance in the green wavelength range, and a high spectral transmittance in the blue wavelength range within the visible light wavelength range. The maximum spectral transmittance in each of the green and blue wavelength ranges is approximately equal to the maximum spectral transmittance in the red wavelength range. The spectral transmittance in the remaining wavelength ranges, including the wavelength range of 550 nm to 600 nm, is approximately zero. In the example shown in FIG. 13C , the red wavelength range is 640 nm to 710 nm, the green wavelength range is 500 nm to 550 nm, and the blue wavelength range is 410 nm to 460 nm. This bandpass filter 30 is advantageous for detecting red light to obtain a first signal, detecting one of green and blue light to obtain a second signal, and detecting the other of green and blue light to obtain a third signal.

[0122] 14A to 14C are diagrams schematically illustrating three other examples of the optical spectrum of the bandpass filter 30. In the example illustrated in FIG. 14A , unlike the example illustrated in FIG. 13A , the maximum spectral transmittance in the blue wavelength range is lower than the maximum spectral transmittance in the red wavelength range. In the example illustrated in FIG. 14B , unlike the example illustrated in FIG. 13B , the maximum spectral transmittance in the green wavelength range is lower than the maximum spectral transmittance in the red wavelength range. In the example illustrated in FIG. 14C , unlike the example illustrated in FIG. 13C , the maximum spectral transmittance in each of the green and blue wavelength ranges is lower than the maximum spectral transmittance in the red wavelength range.

[0123] 14A to 14C , by increasing the exposure time, the intensity of the first signal can be increased and the possibility of the intensity of the second signal and the intensity of the third signal being saturated can be reduced. When the maximum spectral transmittance in each of the green and blue wavelength ranges is half or less of the maximum spectral transmittance in the red wavelength range, the possibility of saturation can be effectively reduced.

[0124] [Timing of Emission of Light from Light Source 50] A modified example of the timing of emission of light from the light source 50 included in the measurement device 100B according to embodiment 2 will be described below with reference to Fig. 15. The light source 50 may emit light intermittently rather than continuously.

[0125] FIG. 15 is a diagram schematically illustrating a modified example of the timing of light emission from the light source 50. "ON" in FIG. 15 represents a state in which light is being emitted from the light source 50, and "OFF" in FIG. 15 represents a state in which light emission from the light source 50 is stopped. In the example shown in FIG. 15 , of a plurality of frames numbered in order, light is emitted from the light source 50 in odd-numbered frames, and light emission from the light source 50 is stopped in even-numbered frames. The frame rate may be, for example, 30 fps or 60 fps. In this way, light emission and stoppage of light emission from the light source 50 are switched at each frame change.

[0126] In a certain frame in the ON state, the photodetector 20 detects reflected light generated when the living body 10 is irradiated with ambient light in addition to light emitted from the light source 50, and in the next frame in the OFF state, it detects reflected light generated when the living body 10 is irradiated with ambient light without light emitted from the light source 50. By subtracting the signal acquired in the next frame in the OFF state from the signal acquired in a certain frame in the ON state, it is possible to acquire a signal from which the influence of ambient light has been removed.

[0127] [Use of Telecentric Lens] When the bandpass filter 30 is an interference filter including a dielectric multilayer film, the spectrum of the bandpass filter 30 depends on the angle of incidence of the incident light. To reduce this effect, the measurement apparatus 100A according to the first embodiment and the measurement apparatus 100B according to the second embodiment may further include a telecentric lens.

[0128] Fig. 16 is a diagram showing a schematic diagram of light from a living organism 10 passing through a telecentric lens 60, passing through a bandpass filter 30, and entering the photodetector 20. As shown in Fig. 16, the telecentric lens 60 is disposed in front of the bandpass filter 30. The telecentric lens 60 includes a convex lens 62 and an aperture 64 located at the focal point of the convex lens 62 on the living organism 10 side. For simplicity, the irradiated portion of the living organism 10 is shown as a flat plate in Fig. 16.

[0129] Of the light from the living organism 10, the light that passes through the diaphragm 64 enters the convex lens 62, and the light from the living organism 10 that does not pass through the diaphragm 64 does not enter the convex lens 62, so the chief ray that passes through the convex lens 62 enters the bandpass filter 30 at the same angle of incidence regardless of the angle of view. The same is true for the upper limit ray and the lower limit ray that pass through the convex lens 62. Therefore, when light from the living organism 10 that passes through the telecentric lens 60 is detected by the photodetector 20 via the bandpass filter 30, the same signal intensity can be maintained even if the angle of view changes due to movement of the living organism 10.

[0130] The sensitivity of light detection can be improved if the F-number of the diaphragm 64 is small. If a plurality of convex lenses 62 are combined in the telecentric lens 60, the diaphragm 64 with a smaller F-number can be used.

[0131] The measurement apparatus 100C according to the third embodiment does not include the bandpass filter 30, but does include a first filter 23a and a second filter 23b, which are interference filters including a dielectric multilayer film. Therefore, for the same reason as above, the measurement apparatus 100C may further include a telecentric lens 60 in front of the photodetector 20.

[0132] (Embodiment 4) Hereinafter, with reference to Fig. 17, a configuration example of a biomeasurement system according to embodiment 4 in which a biomeasurement device is installed in a mobile body will be described. This biomeasurement system acquires biometric information of an occupant of the mobile body. In the following description, the mobile body is an automobile, but it may also be, for example, a ship or an airplane. Furthermore, in the following description, the biomeasurement device is the measurement device 100A according to embodiment 1, but it may also be configured, for example, by excluding the bandpass filter 30 from the measurement device 100A according to embodiment 1.

[0133] [Biometric Measurement System] Fig. 17 is a diagram schematically illustrating the configuration of a biometric measurement system according to an exemplary embodiment of the present disclosure. Fig. 17 also illustrates a living body 10 as an occupant of a vehicle. In the example illustrated in Fig. 17, the living body 10 is sitting in the driver's seat and driving a moving body, but this example is not limiting. The living body 10 may also be sitting in the passenger seat or a back seat. In the following description, the biometric measurement system will also be simply referred to as a "measurement system."

[0134] 17 includes a light source 50-1 that is installed on a moving body and emits light from a direction that is easily visible to the living body 10, and a light source 50-2 that is installed on the moving body and emits light from a direction that is difficult to see by the living body 10. In this specification, there may be cases where no particular distinction is made between the light source 50-1 and the light source 50-2.

[0135] The measurement system 200 further includes a photodetector 20 and a bandpass filter 30 installed on the mobile object. The photodetector 20 and the bandpass filter 30 may be replaced with a photodetector 20-1 shown in FIG. 11 . The measurement system 200 further includes a processing device 40 installed on the mobile object. In the processing device 40, a control circuit 42 controls not only the processing operation of a signal processing circuit 44 but also the emission operations of light sources 50-1 and 50-2.

[0136] The light source 50-1, the light source 50-2, the photodetector 20, the bandpass filter 30, and the processor 40 will be described in detail below.

[0137] <Light Source 50-1 and Light Source 50-2> The light source 50-1 emits blue light to illuminate the living organism 10. The living organism 10 visually recognizes the blue light. Blue light has a strong relaxing effect, and light with a wavelength of 470 nm in particular is said to have a strong sedative effect. Therefore, the blue light emitted from the light source 50-1 can calm the living organism 10 even if the living organism 10 is in a stressed or excited state while driving. By creating a light space centered on blue in the interior of a mobile body, it is possible to guide the living organism 10 to drive safely. The blue light emitted from the light source 50-1 is also useful for acquiring a second signal.

[0138] The light source 50-2, separate from the light source 50-1, emits blue light for illuminating the living organism 10. The blue light emitted from the light source 50-2 illuminates the cheek of the living organism 10 from diagonally behind the living organism 10. Since the living organism 10 is illuminated not only by the blue light emitted from the light source 50-1 but also by the blue light emitted from the light source 50-2, the signal-to-noise ratio of the second signal can be improved.

[0139] The light emitted from the light source 50-2 is difficult for the living body 10 to see. Therefore, the light source 50-2 may emit red light, which is also a danger color. By emitting blue light from the light source 50-1 and red light from the light source 50-2, the difference in intensity between the first signal and the second signal can be reduced, thereby balancing the intensities of the two.

[0140] The light source 50-2 is not limited to emitting blue light or red light, and may be a light source that emits light of other colors. For example, the light source 50-2 may be configured to emit white light.

[0141] <Photodetector 20 and Bandpass Filter 30> In the photodetector 20, the first photodetector element 24a detects light from the living body 10, more specifically, reflected light from the living body 10 that is caused by red light, via the first filter 22a. When the light source 50-1 and the light source 50-2 emit blue light, the red light may be, for example, light from an interior light separately installed in the moving body.

[0142] In the photodetector 20, the second photodetector element 24b detects light from the living body 10, more specifically, reflected light from the living body 10 that is caused by blue light, via the second filter 22b. The bandpass filter 30 is disposed in front of the photodetector 20.

[0143] <Processing Device 40> In the processing device 40, the control circuit 42 causes the signal processing circuit 44 to generate biometric information of the living body 10 based on the first signal and the second signal. The control circuit 42 may further perform the following operations.

[0144] The control circuit 42 determines the psychological state of the living organism 10 based on the biological information of the living organism 10. The psychological state of the living organism 10 may be, for example, a state of stress or excitement of the living organism 10. The control circuit 42 causes the light source 50-1 to control the output of blue light based on the psychological state of the living organism 10. An example of controlling the output of blue light is to increase or decrease the intensity of the blue light.

[0145] More specifically, the operation of the control circuit 42 is as follows: The control circuit 42 determines whether the level of stress or excitement of the living organism 10 is high based on the biological information of the living organism 10. For example, if the heart rate is equal to or higher than a predetermined threshold, the control circuit 42 determines that the level of stress or excitement of the living organism 10 is high.

[0146] When the control circuit 42 determines that the living body 10 is highly stressed or excited, it controls the light source 50-1 to increase the intensity of blue light, thereby calming the living body 10 and guiding the living body 10 to drive safely.

[0147] [Installation Position of Each Component] The installation position of each component is as follows: By installing each component in an appropriate position using the configuration of the moving body, it is possible to effectively acquire biometric information of the living body 10.

[0148] <Light Source 50-1> When the living organism 10 is sitting in the driver's seat, the light source 50-1 may be installed, for example, on the inside of the driver's door and / or around the steering wheel. When the living organism 10 is sitting in the passenger seat, the light source 50-1 may be installed, for example, on the inside of the passenger's door and / or around the glove box. When the living organism 10 is sitting in the back seat, the light source 50-1 may be installed, for example, on the inside of the back seat door and / or behind the front seat. In this way, the light source 50-1 may be installed around the seat where the living organism 10 is sitting so that the blue light emitted from the light source 50-1 can be seen by the living organism 10.

[0149] <Light Source 50-2> When the living body 10 is sitting in the driver's seat or the passenger seat, the light source 50-2 may be installed, for example, on the center pillar as shown in Fig. 17. When the living body 10 is sitting in the rear seat, the light source 50-2 may be installed, for example, on the rear pillar. In either case, there are the following advantages: The light source 50-2 does not obstruct the field of view of the living body 10.

[0150] <Light detection device 20> When the living body 10 is sitting in the driver's seat or the passenger seat, the light detection device 20 can be installed, for example, on the center pillar of the automobile, similar to the light source 50-2. In this case, the following advantages are obtained: The light detection device 20 does not obstruct the field of view of the living body 10. Since the distance from the living body 10 to the light detection device 20 is short, the light detection device 20 can effectively detect light from the living body 10.

[0151] When the living body 10 is sitting in the driver's seat, the light detection device 20 may be installed not only on the center pillar but also at the back center of the steering wheel of the car, for example. In this case, the following advantages are obtained. - Because the light detection device 20 is located in front of the living body 10, it can detect light from the entire face of the living body 10, enabling stable measurement of biometric information. - The light detection device 20 does not obstruct the field of vision of the living body 10. - A monitoring camera for the living body 10 installed in the center of the steering wheel can also be used as the light detection device 20.

[0152] If the living body 10 is sitting in the passenger seat, the light detection device 20 may be installed not only on the center pillar but also, for example, in the glove box in front of the passenger seat. In this case, the following advantages are obtained: - Since the light detection device 20 is located in front of the living body 10, it can detect light from the entire face of the living body 10, enabling stable measurement of biological information. - The light detection device 20 does not obstruct the field of view of the living body 10.

[0153] If the living body 10 is sitting in the back seat, the light detection device 20 can be installed on the rear pillar, for example, similar to the light source 50-2. In this case, the following advantages are obtained: The light detection device 20 does not obstruct the field of view of the living body 10. Since the distance from the living body 10 to the light detection device 20 is short, the light detection device 20 can effectively detect light from the living body 10.

[0154] The bandpass filter 30 is disposed in front of the photodetector 20 and is therefore installed at the same position as the photodetector 20 .

[0155] <Processing Device 40> The processing device 40 may be installed, for example, on a center pillar, similar to the light source 50-2, or at any other position in the vehicle. Alternatively, the processing device 40 may be installed in a remote location away from the vehicle. When the processing device 40 is installed in a remote location, the processing device 40 controls the emission operations of the light sources 50-1 and 50-2 via wireless communication, and acquires the signal output from the light detection device 20 via wireless communication.

[0156] As described above, the measurement system 200 according to the fourth embodiment can effectively acquire biological information of the living body 10, who is an occupant of the moving body, by placing each component in an appropriate position using the configuration of the moving body. In this respect, even if the first filter 22a included in the light detection device 20 is a general red filter, the measurement system 200 according to the fourth embodiment does not necessarily need to include the bandpass filter 30.

[0157] Furthermore, according to the measurement system 200 of embodiment 4, if it is determined that the level of stress or excitement in the living organism 10 is high, the intensity of the blue light emitted from the light source 50-1 can be increased to calm the living organism 10.

[0158] In the measurement system according to the fourth embodiment, the light source 50-1 is configured to emit blue light, but it may be configured to emit light other than blue light.

[0159] [Additional Notes] The above description of the embodiments discloses the following techniques.

[0160] (Technology 1) A biomeasurement device comprising: a bandpass filter; a photodetector; and a processing circuit, wherein the photodetector includes: a first filter that transmits red light; a second filter that transmits one of green and blue light; a first photodetector element that detects light from a living organism via the first filter; and a second photodetector element that detects light from the living organism via the second filter, wherein the processing circuit generates biometric information of the living organism based on a first light detected by the first photodetector element and a second light detected by the second photodetector element, and wherein the bandpass filter suppresses transmission of at least a portion of light in a wavelength range of 550 nm to 600 nm from the light from the living organism that is incident on the first photodetector element.

[0161] In this biometric measurement device, the bandpass filter can prevent biometric information from being mixed into the first light, so that biometric information can be effectively acquired based on the first light and the second light.

[0162] (Technology 2) The bioinstrumentation device according to Technology 1, wherein the optical spectrum of the first filter has a peak in a wavelength range of 550 nm to 800 nm.

[0163] In this bioinstrumentation device, a general red filter can be used as the first filter.

[0164] (Technology 3) The bioinstrumentation device according to Technology 1 or 2, wherein the optical spectrum of the first filter has a spectral transmittance of 30% or more in at least a part of a wavelength range of 550 nm or more and 600 nm or less.

[0165] In this bioinstrumentation device, a general red filter can be used as the first filter.

[0166] (Technology 4) A biomeasurement device according to any one of technologies 1 to 3, wherein the first photodetector element outputs a first signal based on the first light, the second photodetector element outputs a second signal based on the second light, and the processing circuit generates the bioinformation based on a difference between a time change in intensity of the first signal and a time change in intensity of the second signal.

[0167] In this biometric device, biometric information can be generated by simple arithmetic processing, thereby reducing the burden of arithmetic processing on the processing circuit.

[0168] (Technology 5) A biomeasurement device according to any one of technologies 1 to 4, wherein the photodetector device further comprises: a third filter that transmits the other of the green and blue light; and a third photodetector element that detects light from the living organism via the third filter; and the processing circuit generates hue information of the living organism based on a third light detected by the third photodetector element in addition to the first light and the second light.

[0169] This biometric device can generate more accurate hue information of a living body.

[0170] (Technology 6) The biomeasurement device according to Technology 5, wherein the light detection device comprises: a plurality of first filters including the first filter; a plurality of second filters including the second filter; a plurality of third filters including the third filter; a plurality of first light detection elements including the first light detection element; a plurality of second light detection elements including the second light detection element; and a plurality of third light detection elements including the third light detection element; wherein the processing circuit generates the hue information based on the light detected by the plurality of first light detection elements, the light detected by the plurality of second light detection elements, and the light detected by the plurality of third light detection elements, and determines, based on the hue information, the first light detection element, the second light detection element, and the third light detection element that correspond to the position of the face of the living body, among the plurality of first light detection elements, the plurality of second light detection elements, and the plurality of third light detection elements.

[0171] This biometric device can identify the position of the face of a living body even if the living body moves.

[0172] (Technology 7) The biomeasurement device according to any one of Technologies 1 to 6, wherein the bandpass filter has a maximum spectral transmittance in one of the green and blue wavelength ranges that is lower than a maximum spectral transmittance in the red wavelength range.

[0173] In this bioinstrumentation device, by lengthening the exposure time, it is possible to increase the intensity of the first signal and reduce the possibility of the intensity of the second signal becoming saturated.

[0174] (Technology 8) The bioinstrumentation device according to any one of Technologies 1 to 7, further comprising a light source that emits the red light and one of the green and blue light for irradiating the living body.

[0175] This biometric device can acquire biometric information using a light source even in the absence of ambient light.

[0176] (Technology 9) The bioinstrumentation device according to Technology 8, wherein a peak intensity of one of the green and blue light is lower than a peak intensity of the red light.

[0177] In this bioinstrumentation device, by lengthening the exposure time, it is possible to increase the intensity of the first signal and reduce the possibility of the intensity of the second signal becoming saturated.

[0178] (Technology 10) A biomeasurement device comprising: a photodetector; and a processing circuit, wherein the photodetector includes: a first filter that transmits red light; a second filter that transmits one of green and blue light; a first photodetector element that detects light from a living organism via the first filter; and a second photodetector element that detects light from the living organism via the second filter, wherein the processing circuit generates biometric information of the living organism based on a first light detected by the first photodetector element and a second light detected by the second photodetector element, and wherein the first filter is an interference filter including a dielectric multilayer film and suppresses transmission of at least a part of light in a wavelength range of 550 nm to 600 nm.

[0179] In this biometric measurement device, the first filter can prevent biometric information from being mixed into the first light, so that biometric information can be effectively acquired based on the first light and the second light.

[0180] (Technology 11) A biometric measurement system comprising: a light source installed in a moving body, the light source emitting blue light for illuminating an occupant of the moving body; a photodetector installed in the moving body, the photodetector detecting reflected light from the occupant caused by the blue light; and a processing circuit, wherein the photodetector includes: a first filter that transmits red light; a second filter that transmits the blue light; a first photodetector element that detects light from the occupant via the first filter; and a second photodetector element that detects the reflected light of the light from the occupant via the second filter, and the processing circuit generates biometric information of the occupant based on the light detected by the first photodetector element and the light detected by the second photodetector element.

[0181] In this biometric measurement device, by utilizing the configuration of the moving body and placing each component in an appropriate position, biometric information can be obtained effectively.

[0182] (Technology 12) The bioinstrumentation system according to Technology 11, wherein the blue light includes light having a wavelength of 470 nm.

[0183] This biometric device uses light with a wavelength of 470 nm, which has a strong calming effect, to calm the occupants.

[0184] (Technology 13) The biometric measurement system according to Technology 11 or 12, wherein the processing circuit determines a psychological state of the occupant based on the biological information, and causes the light source to control the output of the blue light based on the psychological state.

[0185] This biometric device can calm the occupant based on the occupant's psychological state.

[0186] (Technology 14) The biometric measurement system described in Technology 13, wherein the processing circuit determines whether the occupant's level of stress or excitement is high based on the biometric information, and if it determines that the level of stress or excitement is high, causes the light source to increase the intensity of the blue light.

[0187] The biometric device can calm the occupant if they are experiencing high levels of stress or agitation.

[0188] (Technology 15) The biometric measurement system according to any one of Techniques 11 to 14, wherein the light source is installed around a seat on which the occupant sits.

[0189] In this biometric device, the occupant can see the blue light.

[0190] (Technology 16) The biometric measurement system according to any one of techniques 11 to 15, wherein the moving body is an automobile, the light source and the light detection device are installed on a center pillar or a rear pillar of the automobile, and the light detection device detects reflected light from the cheek of the occupant.

[0191] In this biometric device, the light source and the light detection device do not obstruct the view of the occupant.

[0192] (Technology 17) The bioinstrumentation system according to any one of Technologies 11 to 16, wherein the moving body is an automobile, and the light detection device is installed on a steering wheel or a glove box of the automobile.

[0193] In this biometric measurement device, the photodetector is located in front of the occupant, so light from the entire face of the occupant can be detected, enabling stable measurement of biometric information.

[0194] (Technology 18) The bioinstrumentation device according to Technology 10, further comprising a light source that emits the red light and one of the green and blue light for irradiating the living body.

[0195] This biometric device can acquire biometric information using a light source even in the absence of ambient light.

[0196] (Technology 19) The biomeasurement device described in Technology 10 or 18, wherein the photodetector device further includes a third filter that transmits the other of the green and blue light, and a third photodetector element that detects light from the living organism via the third filter, and the processing circuit generates hue information of the living organism based on a third light detected by the third photodetector element in addition to the first light and the second light.

[0197] This biometric device can generate more accurate hue information of a living body.

[0198] (Technology 20) The biomeasurement device according to Technology 19, wherein the photodetection device comprises: a plurality of first filters including the first filter; a plurality of second filters including the second filter; a plurality of third filters including the third filter; a plurality of first photodetection elements including the first photodetection element; a plurality of second photodetection elements including the second photodetection element; and a plurality of third photodetection elements including the third photodetection element; wherein the processing circuit generates the hue information based on the light detected by the plurality of first photodetection elements, the light detected by the plurality of second photodetection elements, and the light detected by the plurality of third photodetection elements, and determines, based on the hue information, the first photodetection element, the second photodetection element, and the third photodetection element that correspond to the position of the face of the living body.

[0199] This biometric device can identify the position of the face of a living body even if the living body moves.

[0200] (Technology 21) The bioinstrumentation system according to any one of Technologies 11 to 17, further comprising a bandpass filter that suppresses transmission of at least a part of light in a wavelength range of 550 nm to 600 nm, of the light from the occupant that is incident on the first filter.

[0201] In this biometric measurement device, the bandpass filter can prevent biometric information from being mixed into the first light, so that biometric information can be effectively acquired based on the first light and the second light.

[0202] (Technology 22) The bioinstrumentation system according to any one of Techniques 11 to 17, wherein the first filter suppresses transmission of at least a part of light in a wavelength range of 550 nm to 600 nm.

[0203] In this biometric measurement device, the first filter can prevent biometric information from being mixed into the first light, so that biometric information can be effectively acquired based on the first light and the second light.

[0204] The technology of the present disclosure is useful, for example, in a biometric measurement device that acquires biometric information. The technology of the present disclosure can also be applied, for example, to biometric, medical, and cosmetic sensing systems and in-vehicle sensing systems.

[0205] 10 Living body 20, 20-1 Photodetection device 22a, 23a First filter 22b, 23b Second filter 22c Third filter 24a First photodetection element 24b Second photodetection element 30 Bandpass filter 40 Processing device 42 Control circuit 44 Signal processing circuit 46 Memory 50, 50-1, 50-2 Light source 52 Wavelength conversion element 54 Light-emitting element 54a First light-emitting element 54b Second light-emitting element 54c Third light-emitting element 60 Telecentric lens 62 Convex lens 64 Aperture 100A, 100B, 100C Measurement device 200 Measurement system

Claims

1. A biomeasurement device comprising: a bandpass filter; a photodetector; and a processing circuit, wherein the photodetector includes a first filter that transmits red light; a second filter that transmits one of green and blue light; a first photodetector element that detects light from the living organism through the first filter; and a second photodetector element that detects light from the living organism through the second filter, wherein the processing circuit generates bioinformation of the living organism based on a first light detected by the first photodetector element and a second light detected by the second photodetector element, and the bandpass filter suppresses the transmission of at least a portion of light in the wavelength range of 550 nm or more and 600 nm or less of the light from the living organism that is incident on the first photodetector element.

2. The bioinstrumentation device according to claim 1, wherein the optical spectrum of the first filter has a peak in the wavelength range of 550 nm or more and 800 nm or less.

3. The bioinstrumentation device according to claim 1 or 2, wherein the optical spectrum of the first filter has a spectral transmittance of 30% or more in at least a portion of the wavelength range from 550 nm to 600 nm.

4. The biomeasurement device of claim 1 or 2, wherein the first light detection element outputs a first signal based on the first light, the second light detection element outputs a second signal based on the second light, and the processing circuit generates the bioinformation based on the difference between the change in intensity of the first signal over time and the change in intensity of the second signal over time.

5. The biomeasurement device of claim 1 or 2, further comprising: a third filter that transmits the other of the green and blue light; and a third photodetector element that detects light from the living organism through the third filter; and the processing circuit generates hue information of the living organism based on a third light detected by the third photodetector element in addition to the first light and the second light.

6. The biomeasurement device of claim 5, wherein the optical detection device comprises a plurality of first filters including the first filter, a plurality of second filters including the second filter, a plurality of third filters including the third filter, a plurality of first optical detection elements including the first optical detection element, a plurality of second optical detection elements including the second optical detection element, and a plurality of third optical detection elements including the third optical detection element; and the processing circuit generates the hue information based on the light detected by the plurality of first optical detection elements, the light detected by the plurality of second optical detection elements, and the light detected by the plurality of third optical detection elements, and determines, based on the hue information, a first optical detection element, a second optical detection element, and a third optical detection element that correspond to the position of the living body's face, among the plurality of first optical detection elements, the plurality of second optical detection elements, and the plurality of third optical detection elements.

7. The bioinstrumentation device according to claim 1 or 2, wherein the bandpass filter has a maximum spectral transmittance in one of the green and blue wavelength ranges lower than a maximum spectral transmittance in the red wavelength range.

8. The bioinstrumentation device according to claim 1 or 2, further comprising a light source that emits the red light and one of the green and blue lights for irradiating the living body.

9. The bioinstrumentation device according to claim 8, wherein the peak intensity of one of the green and blue light is lower than the peak intensity of the red light.

10. A biomeasurement device comprising: a photodetector; and a processing circuit, wherein the photodetector includes a first filter that transmits red light, a second filter that transmits one of green and blue light, a first photodetector element that detects light from the living organism through the first filter, and a second photodetector element that detects light from the living organism through the second filter, wherein the processing circuit generates bioinformation of the living organism based on the first light detected by the first photodetector element and the second light detected by the second photodetector element, and the first filter is an interference filter including a dielectric multilayer film and suppresses the transmission of at least a portion of light in the wavelength range of 550 nm to 600 nm.

11. A biomeasurement system comprising: a light source installed in a moving body, emitting blue light to illuminate an occupant of the moving body; a photodetector installed in the moving body, detecting reflected light from the occupant caused by the blue light; and a processing circuit, wherein the photodetector includes a first filter that transmits red light, a second filter that transmits the blue light, a first photodetector element that detects light from the occupant through the first filter, and a second photodetector element that detects the reflected light of the light from the occupant through the second filter, and the processing circuit generates biometric information of the occupant based on the light detected by the first photodetector element and the light detected by the second photodetector element.

12. The bioinstrumentation system of claim 11, wherein the blue light includes light having a wavelength of 470 nm.

13. The biomeasurement system according to claim 11 or 12, wherein the processing circuit determines a psychological state of the occupant based on the bioinformation, and controls the light source to output the blue light based on the psychological state.

14. The biomeasurement system of claim 13, wherein the processing circuit determines whether the occupant's level of stress or excitement is high based on the bioinformation, and if it determines that the level of stress or excitement is high, causes the light source to increase the intensity of the blue light.

15. The bioinstrumentation system according to claim 11 or 12, wherein the light source is installed in the vicinity of a seat on which the passenger sits.

16. The bioinstrumentation system of claim 11 or 12, wherein the moving body is an automobile, the light source and the light detection device are installed on a center pillar or a rear pillar of the automobile, and the light detection device detects reflected light from the cheek of the occupant.

17. The bioinstrumentation system according to claim 11 or 12, wherein the moving body is an automobile, and the optical detection device is installed on a steering wheel or a glove box of the automobile.

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