JP2016182286A - Biological information sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biological information sensor capable of increasing measurement accuracy.SOLUTION: A biological information sensor 1 is equipped with a light receiving part 11 and generates information on a living body based on a signal from the light receiving part 11. The light receiving part 11 includes a first light sensor 111 for converting a first light to a first signal. The first light sensor 111 includes a first photoelectric conversion element 111A and a first color filter 111B. The first photoelectric conversion element 111A converts the first light to the first signal. The first color filter 111B is formed on a light path to the first photoelectric conversion element 111A, and transmits the first light. The biological information sensor 1 further includes an infrared light removal layer 101 formed on the light path to the first photoelectric conversion element 111A.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a biological information sensor, and more particularly to a wearable biological information sensor.

  Conventionally, wearable biological information sensors are known. For example, Japanese Unexamined Patent Application Publication No. 2012-143316 (Patent Document 1) discloses a wearable biological information sensor. The biological information sensor includes first and second optical sensors and an arithmetic circuit. The first optical sensor receives a first light emitting unit that emits light having a first light emission intensity to the living body, and light reflected by the emitted light from the first light emitting unit in the living body, and outputs a first received light signal. And a first light receiving unit to be generated. The second light sensor emits light having a second light emission intensity weaker than the first light emission intensity to the living body, and light reflected from the light emitted from the second light emitting part in the living body. And a second light receiving unit that generates a second light receiving signal. The arithmetic circuit subtracts the second received light signal from the first received light signal to obtain pulse wave data.

JP 2012-143316 A

  When biological information such as pulse or blood oxygen saturation concentration is measured while wearing a biological information sensor on the body and exercising outdoors, sunlight including infrared light is incident on the biological information sensor. Measurement errors can occur.

  Therefore, a main object of the present invention is to provide a biological information sensor that can increase measurement accuracy.

  The biological information sensor according to the present invention includes a light receiving unit, and generates information related to a living body based on a signal from the light receiving unit. The light receiving unit includes a first photosensor that converts the first light into a first signal. The first photosensor includes a first photoelectric conversion element and a first color filter. The first photoelectric conversion element converts the first light into a first signal. The first color filter is formed on the optical path to the first photoelectric conversion element and transmits the first light. The biological information sensor further includes an infrared light removal layer formed on the optical path to the first photoelectric conversion element.

  The color filter is a color resist film containing pigments such as red, green, and blue. In addition to the resist component, a pigment dispersion resist in which a pigment is finely dispersed as a color material is used as the color resist.

  With such a configuration, light from which infrared light has been removed by the infrared light removal layer is incident on the first photosensor. Since the first color filter transmits the first light included in the light transmitted through the infrared light removal layer, most of the light received by the first photoelectric conversion element is the first light. As a result, the biological information sensor can generate information on the living body with almost no influence of infrared light. That is, according to the biological information sensor of the present invention, the measurement accuracy can be increased.

  Preferably, the biological information sensor further includes an arithmetic control unit. The arithmetic control unit generates information related to the living body based on a signal from the light receiving unit. The light receiving unit further includes a second photosensor. The second optical sensor converts the second light into a second signal. The second photosensor has a second photoelectric conversion element and a second color filter. The second photoelectric conversion element converts the second light into a second signal. The second color filter is formed on the optical path to the second photoelectric conversion element, and transmits the second light. The infrared light removal layer is also formed on the optical path to the second photoelectric conversion element. The arithmetic control unit receives the first signal and the second signal from the light receiving unit, and generates information related to the living body based on the first signal and the second signal.

  Preferably, the light receiving unit further includes a first substrate on which the first photosensor and the second photosensor are formed. The infrared light removal layer is formed on the surface of the first substrate.

Examples of the signal level include a voltage value or a current value of an electric signal.
Preferably, the infrared light removal layer includes an infrared cut filter. The infrared cut filter covers the first color filter and the second color filter.

  The infrared cut filter is a multilayer film in which a plurality of thin films having different refractive indexes are stacked and light having a shorter wavelength than infrared light is transmitted. Examples of the plurality of thin films having different refractive indexes include those obtained by periodically laminating a TiO 2 film and a SiO 2 film by a sputtering method.

  Preferably, the infrared light removal layer includes an infrared cut resin. The infrared cut resin covers the first substrate.

  The infrared cut resin is a resin containing a material that absorbs infrared light (for example, light having a wavelength of 750 nm or more).

  Preferably, the infrared light removal layer includes an infrared cut filter and an infrared cut resin. The infrared cut filter covers the first color filter and the second color filter. The infrared cut resin is laminated on the infrared cut filter and covers the first substrate.

  Preferably, the biological information sensor further includes a light emitting unit, a second substrate, a first light shielding wall, and a second light shielding wall. The light emitting unit emits light including the first light and the second light. The second substrate has a light emitting unit, a light receiving unit, and an arithmetic control unit. The first light shielding wall is formed so as to surround the light emitting unit and the light receiving unit along the outer periphery of the second substrate. The second light shielding wall partitions the space formed by the second substrate and the first light shielding wall into a space on the side where the light emitting part is located and a space on the side where the light receiving part is located. When the biological information sensor is attached to the living body, the light reflected inside the living body out of the light emitted from the light emitting section enters the light receiving section.

Preferably, the light emitting unit is a light emitting diode that emits white light.
Preferably, the first light is green light. The second light is red light.

  Preferably, the arithmetic control unit generates information related to the living body based on a difference between the level of the first signal and the level of the second signal.

Preferably, the information related to the living body is a heart rate.
The arithmetic control unit generates information related to the living body based on a ratio between the level of the first signal and the level of the second signal.

  Preferably, the information related to the living body is a blood oxygen saturation concentration.

  According to the biological information sensor of the present invention, the measurement accuracy can be increased by removing the infrared light contained in the light incident on the biological information sensor by the infrared light removing layer.

It is sectional drawing which shows the structure of the biometric information sensor according to 1st Embodiment. It is sectional drawing which shows the structure of the light-receiving part with which the biometric information sensor according to 1st Embodiment is provided. It is a figure which shows the spectral characteristics of an infrared cut filter, G filter, R filter, and a photodiode. It is a functional lineblock diagram of a living body information sensor according to a 1st embodiment. It is a time chart which illustrates operation | movement of the biometric information sensor according to 1st Embodiment. It is sectional drawing which shows the structure of the light-receiving part with which the biometric information sensor according to 2nd Embodiment is provided. It is sectional drawing which shows the structure of the light-receiving part with which the biometric information sensor according to 3rd Embodiment is provided. It is a function block diagram of the biometric information sensor according to 4th Embodiment. It is a figure which shows the relationship between the wavelength of light, the molar absorption coefficient of hemoglobin, the spectral sensitivity of G filter, and the spectral sensitivity of R filter. It is a function block diagram of the calculating part with which the biometric information sensor according to 4th Embodiment is provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[First embodiment]
FIG. 1 is a cross-sectional view showing a configuration of biological information sensor 1 according to the first embodiment. Below, the case where the heart rate is measured as information about a living body by the living body information sensor 1 will be described.

  Referring to FIG. 1, the biological information sensor includes a light emitting unit 10 that is a white LED, a light receiving unit 11 that is an integrated circuit, light shielding walls 13 and 14, lenses 15 and 16, a transparent plate 17, and a substrate 18. And an arithmetic control unit 200.

  A light emitting unit 10, a light receiving unit 11, and an arithmetic control unit 200 are formed on the surface of the substrate 18. The light receiving unit 11 includes a silicon substrate 12 and a G sensor 111 and an R sensor 112 formed on the silicon substrate 12. The arithmetic control unit 200 may be formed on the silicon substrate 12.

  A light shielding wall 14 for preventing external light from entering the light receiving unit 11 is formed at the edge of the surface of the substrate 18 so as to surround the light emitting unit 10 and the light receiving unit 11. A light shielding wall 13 for preventing white light emitted from the light emitting unit 10 from directly entering the light receiving unit 11 is formed at the center of the surface of the substrate 18. That is, the space formed by the light shielding wall 14 is partitioned by the light shielding wall 13 into a space on the side where the light emitting unit 10 is located and a space on the side where the light receiving unit 11 is located.

  A lens 15 is provided in the emission direction of the light emitting unit 10, and a lens 16 is provided in the light receiving direction of the light receiving unit 11. The openings at the lower ends of the light shielding walls 13 and 14 are closed by a transparent plate 17. When detecting the heart rate, the surface of the transparent plate 17 is in close contact with the surface of the human body 50.

  White light emitted from the light emitting unit 10 is applied to the human body 50 via the lens 15 and the transparent plate 17. Of the white light, the light α reflected inside the body enters the light receiving unit 11 via the transparent plate 17 and the lens 15. The intensity of green light in the light α is converted into a signal by the G sensor 111. The intensity of red light in the light α is converted into a signal by the R sensor 112. The arithmetic control unit 200 generates a signal indicating the heart rate based on the signal from the G sensor 111 and the signal from the R sensor 112.

  When the user wears the biological information sensor 1 on the human body 50 and measures the heart rate outdoors or the like, the light β transmitted or reflected from the inside of the human body 50 out of sunlight may enter the light receiving unit 11. The light β derived from sunlight includes infrared light. The G sensor 111 and the R sensor 112 exhibit the strongest sensitivity to green light and red light, respectively, but the sensitivity to infrared light is not zero. Therefore, the light β becomes noise when the biological information sensor 1 measures the heart rate, and may cause an error in the measured heart rate.

  Therefore, in the first embodiment, the infrared light is removed by an infrared light removal layer including an infrared cut filter.

  FIG. 2 is a cross-sectional view showing a configuration of light receiving unit 11 included in biological information sensor 1 according to the first embodiment. Referring to FIG. 2, light receiving unit 11 includes a silicon substrate 12, a G (green light) sensor 111, an R (red light) sensor 112, and an infrared cut filter 101.

  The G sensor 111 includes a photodiode 111A and a G filter 111B, and the R sensor 112 includes a photodiode 112A and an R filter 112B. The G filter 111B transmits green light. The photodiode 111A converts the green light transmitted through the G filter 111B into a signal S1. The R filter 112B transmits red light. The photodiode 112A converts the red light transmitted through the R filter 112B into a signal S2.

  The silicon substrate 12 is divided into an upper layer 12A and a lower layer 12B. A G filter 111B and an R filter 112B are formed on the surface of the upper layer 12A. At the boundary between the upper layer 12A and the lower layer 12B, photodiodes 111A and 112A are provided on the lower layer 12B side. The G filter 111B and the R filter 112B are opposed to the photodiodes 111A and 112A, respectively. Therefore, the light incident on the photodiode 111A passes through the G filter 111B, and the light incident on the photodiode 112A passes through the R filter 112B. That is, the G filter 111B is formed on the optical path to the photodiode 111A, and the R filter 112B is formed on the optical path to the photodiode 112A.

  The infrared cut filter 101 is formed on the surface of the upper layer 12A and covers the G filter 111B and the R filter 112B. Therefore, the light incident on the photodiode 111A and the photodiode 112A passes through the infrared cut filter. That is, the infrared cut filter 101 is formed on the optical path to the photodiode 111A and also formed on the optical path to the photodiode 112A.

  With such a configuration, most of the light input to the photodiode 111A becomes green light, and most of the light input to the photodiode 112A becomes red light. Such a result is due to a difference in spectral characteristics of the infrared cut filter 101, the G filter 111B, and the R filter 112B. Therefore, in the following, focusing on the respective spectral characteristics, it will be described that most of the light input to the photodiode 111A and the photodiode 112A is green light and red light, respectively.

  FIG. 3 is a diagram illustrating spectral characteristics of the infrared cut filter 101, the G filter 111B, the R filter 112B, and the photodiode 111A (112A). In FIG. 3, Cir represents the spectral characteristic of the infrared cut filter 101, Cg represents the spectral characteristic of the G filter 111B, Cr represents the spectral characteristic of the R filter 112B, and C0 represents the spectral characteristic of the photodiode 111A (112A). Indicates.

  When light enters the light receiving unit 11, the light first passes through the infrared cut filter 101. Referring to FIG. 3, the sensitivity of the infrared cut filter 101 in the near-infrared region is almost zero, so that the infrared light included in the light cannot pass through the infrared cut filter 101. The light that has passed through the infrared cut filter 101 passes through the G filter 111B or the R filter 112B. Since the G filter 111B exhibits the highest sensitivity in the green region, it transmits green light. The R filter 112B transmits the red light because it exhibits the highest sensitivity in the red region. As a result, most of the light input to the photodiode 111A is green light, and most of the light input to the photodiode 112A is red light.

  Next, calculation of the heart rate by the arithmetic control unit 200 will be described. FIG. 4 is a functional configuration diagram of the biological information sensor 1. The arithmetic control unit 200 outputs a signal S0, which is a control signal, to the light emitting unit 10 in response to a measurement start instruction from the user. The light emitting unit 10 emits light in response to the signal S0 and emits white light to the human body. White light emitted from the light emitting unit 10 is reflected in the human body and enters the G sensor 111 and the R sensor 112. At this time, white light is absorbed by the skin, blood, etc., and the intensity of the reflected light varies according to the pulse wave and body movement of the human body. Specifically, the intensity of the green light included in the reflected light varies according to the pulse wave and body motion of the human body. The intensity of the red light contained in the reflected light varies according to the movement of the human body, but hardly varies according to the pulsation of the human body.

  The G sensor 111 receives light emitted from the light emitting unit 10 and reflected in the human body, and converts green light of the light into a signal S1. The level (for example, voltage) of the signal S1 increases according to the light intensity of the incident green light. As described above, the level of the signal S1 changes according to the pulsation and body movement of the human body.

  The R sensor 112 receives the light emitted from the light emitting unit 10 and reflected in the human body, and converts the red light thereof into a signal S2. The level (for example, voltage) of the signal S2 increases according to the light intensity of the incident red light. As described above, the signal S2 changes according to the movement of the human body, but hardly changes according to the pulsation of the human body.

  The arithmetic control unit 200 may amplify at least one of the signals S1 and S2 so that the amplitudes of the body motion components that change in the same cycle of the signals S1 and S2 are substantially the same. The arithmetic control unit 200 obtains a signal indicating a level difference between the signal S1 and a signal obtained by amplifying the signal S2, and obtains a pulse wave of the human body based on the signal indicating the level difference.

  FIGS. 5A and 5B are time charts illustrating the operation of the biological information sensor 1. FIG. 5A illustrates the waveforms of the signals S1 and S2, and FIG. 5B illustrates the waveform of the signal S12 indicating the level difference between the signals S1 and S2. 5A and 5B, signal S1 includes a body motion component that varies with a relatively large period and amplitude, and a pulse wave component that varies with a relatively small period and amplitude, and signal S2 is substantially the same as signal S1. Contains the same body motion component. The signal S12 includes only the pulse wave component.

  Referring to FIG. 4 again, operation control unit 200 obtains a heart rate by counting the number of pulses per minute from signal S12, and displays signal S4 indicating the heart rate, for example, as a monitor of a wearable device. Output to the unit 400. Display unit 400 displays characters, images, and the like indicating the heart rate on the screen in accordance with signal S4 from calculation control unit 200. Communication with the display unit 400 may be performed by wire or wirelessly.

  As described above, according to the biological information sensor 1 according to the first embodiment, the infrared light included in the light incident on the light receiving unit 11 is removed by the infrared light removal layer including the infrared cut filter 101. Therefore, the measurement accuracy of heart rate measurement can be increased.

[Second Embodiment]
In the first embodiment, the case where the infrared light removal layer includes an infrared cut filter has been described. The infrared light removal layer is not limited to including an infrared cut filter. 2nd Embodiment demonstrates the case where an infrared-light removal layer contains infrared cut resin.

  The second embodiment is different from the first embodiment only in that the infrared light removal layer includes an infrared cut resin instead of the infrared cut filter. Since other than that is the same as that of 1st Embodiment, description about the same structure is not repeated.

  FIG. 6 is a cross-sectional view showing a configuration of light receiving unit 11 included in biological information sensor 2 according to the second embodiment. Referring to FIG. 6, silicon substrate 12 is entirely covered with infrared cut resin 102. The spectral characteristic of the infrared cut resin 102 is almost the same as that of the infrared cut filter. Therefore, as in the first embodiment, the infrared light included in the light incident on the light receiving unit 11 cannot pass through the infrared cut resin, and most of the light input to the photodiode 111A is green light. Most of the light input to the photodiode 112A is red light.

  As described above, according to the biological information sensor 2 according to the second embodiment, the infrared light included in the light incident on the light receiving unit 11 is removed by the infrared light removal layer including the infrared cut resin 102. Therefore, the measurement accuracy of heart rate measurement can be increased.

[Third embodiment]
In the first embodiment, the case where the infrared light removal layer includes an infrared cut filter has been described, and in the second embodiment, the case where the infrared light removal layer includes an infrared cut resin has been described. That is, in the first embodiment and the second embodiment, the case where the infrared light removal layer is one layer has been described. The infrared light removal layer is not limited to a single layer. In the third embodiment, a case will be described in which the infrared light removal layer includes an infrared cut filter and an infrared cut resin and has two layers.

  The third embodiment is different from the first embodiment only in that the infrared light removal layer includes an infrared cut resin in addition to the infrared cut filter. Since other than that is the same as that of 1st Embodiment, description about the same structure is not repeated.

  FIG. 7 is a cross-sectional view showing a configuration of light receiving unit 11 included in biological information sensor 3 according to the third embodiment. Referring to FIG. 7, in the third embodiment, as in the first embodiment, infrared cut filter 101 is formed on the surface of upper layer 12A of silicon substrate 12, and G filter 111B and R filter 112B. And covering. Further, in the third embodiment, the infrared cut resin 102 is laminated on the infrared cut filter 101. The infrared cut resin 102 covers the entire silicon substrate 12.

  With such a configuration, the infrared light included in the light incident on the light receiving unit 11 cannot pass through the infrared cut resin and the infrared cut filter, and most of the light input to the photodiode 111A becomes green light. Most of the light input to the diode 112A is red light.

  As described above, according to the biological information sensor 3 according to the third embodiment, the infrared light included in the light incident on the light receiving unit 11 is infrared including the infrared cut filter 101 and the infrared cut resin 102. Since it is removed by the light removal layer, the measurement accuracy of heart rate measurement can be increased.

  Moreover, since there are two infrared light removal layers, more infrared light can be removed as compared with the first and second embodiments. As a result, the measurement accuracy of heart rate measurement can be further increased.

[Fourth embodiment]
In the first to third embodiments, the case where the heart rate measurement accuracy is increased by using the infrared light removal layer has been described. Conventionally, since the blood oxygen saturation concentration (SpO2) has been measured using red light and infrared light, the first to third embodiments in which the infrared light is removed by the infrared light removal layer. In the embodiment, it is difficult to measure a blood oxygen saturation concentration organism (SpO2) by a conventional method. Therefore, in the following, a fourth embodiment in which blood oxygen saturation concentration (SpO2) can be measured while using an infrared light removal layer by using green light will be described.

  In the fourth embodiment, the infrared light removal layer includes an infrared cut filter, as in the first embodiment. In addition, the calculation control unit 200 in the first embodiment is replaced with a calculation control unit 300. Since the other configuration is the same as that of the first embodiment, description of the same configuration will not be repeated.

  FIG. 8 is a functional configuration diagram of the biological information sensor 4 according to the fourth embodiment. Referring to FIG. 8, arithmetic control unit 300 includes control unit 310, amplifiers 311 and 321, AD (Analog-to-Digital) converters 312 and 322, and a high-pass filter (HPF). 313, 323, a low-pass filter (LPF) 314, 324, and an arithmetic unit 30 are included.

  The control unit 310 outputs a signal S0 as a control signal to the light emitting unit 10 and the calculation unit 30 in response to a measurement start instruction from the user. The calculation unit 30 performs calculations necessary for calculating the blood oxygen saturation concentration in response to the signal S0.

  The amplifier 311 amplifies the signal S1 output from the G sensor 111. The AD converter 312 converts the output signal of the amplifier 311 into a digital signal. The high-pass filter 313 removes a direct current component from the output signal of the AD converter 312. The low pass filter 314 removes a noise component of the signal that has passed through the high pass filter 313. The signal that has passed through the low-pass filter 314 is output to the arithmetic unit 30 as a digital signal D1.

  The amplifier 321 amplifies the signal S2 output from the R sensor 112. The AD converter 322 converts the output signal of the amplifier 321 into a digital signal. The high-pass filter 323 removes a direct current component from the output signal of the AD converter 322. The low pass filter 324 removes a noise component of the signal transmitted through the high pass filter 323. The signal that has passed through the low-pass filter 324 is output to the arithmetic unit 30 as a digital signal D2.

  Hereinafter, the calculation unit 30 that calculates the blood oxygen saturation concentration will be described. Prior to the description, a method for calculating the blood oxygen saturation concentration will be schematically described.

  FIG. 9 is a diagram illustrating the relationship among the wavelength [nm] of light, the molar absorption coefficient [cm−1 / M] of hemoglobin, the spectral sensitivity of the G filter 111B, and the spectral sensitivity of the R filter 112B. In FIG. 9, H1 represents the molar absorption coefficient of oxyhemoglobin, and H2 represents the molar absorption coefficient of reduced hemoglobin. Cg represents the spectral characteristic of the G filter 111B, and Cr represents the spectral characteristic of the R filter 112B. Oxyhemoglobin is contained in blood in arteries, and reduced hemoglobin is contained in blood in veins.

  The blood oxygen saturation concentration is the ratio of the concentration of oxyhemoglobin to the sum of the concentration of reduced hemoglobin and the concentration of oxyhemoglobin. Infrared light is easier to absorb oxyhemoglobin than reduced hemoglobin. This means that the molar absorption coefficient of oxyhemoglobin for infrared light is larger than the molar absorption coefficient of reduced hemoglobin for infrared light. Red light is easier to absorb reduced hemoglobin than oxidized hemoglobin. This means that the molar absorption coefficient of reduced hemoglobin for red light is larger than the molar absorption coefficient of oxyhemoglobin for red light. Conventionally, the blood oxygen saturation concentration has been determined using the difference in properties between infrared light and red light. Referring to FIG. 9, although the molar absorption coefficient of oxyhemoglobin and the molar absorption coefficient of reduced hemoglobin for infrared light having a wavelength in the vicinity of 800 [nm] are substantially equal to each other, conventional infrared light having this wavelength can be used. The blood oxygen saturation concentration can be determined by the calculation method. That is, if the light has a wavelength such that the molar absorption coefficient of oxyhemoglobin and the molar absorption coefficient of reduced hemoglobin are equal, the blood oxygen saturation concentration can be determined by a conventional calculation method.

  In the fourth embodiment, infrared light cannot be used because infrared light is removed by an infrared light removal layer including an infrared cut filter. However, the molar absorption coefficient of oxyhemoglobin and the molar absorption coefficient of reduced hemoglobin for green light having a wavelength λ1 near 540 [nm] are substantially equal. Therefore, in the fourth embodiment, blood oxygen saturation concentration is calculated by using green light instead of infrared light.

  Next, the functional configuration of the calculation unit 30 will be described with reference to FIG. Referring to FIG. 10, calculation unit 30 includes amplitude extraction units 31 and 32, signal ratio calculation unit 33, and SpO2 calculation unit 34.

  The amplitude extraction unit 31 extracts the amplitude value of the intensity of green light from the digital signal D1 from the G sensor 111, and outputs the amplitude value to the signal ratio calculation unit 33 as the digital signal D1L. The amplitude extraction unit 32 extracts the amplitude value of the intensity of red light from the digital signal D2 from the R sensor 112, and outputs it as a digital signal D2L to the signal ratio calculation unit 33. When the amplitude extraction units 31 and 32 extract the amplitude value of the light intensity from the digital signal, the amplitude value may be amplified at a predetermined ratio. The signal ratio calculation unit 33 calculates a ratio R (= V1 / V2) between the voltage value V1 of the digital signal D1L and the voltage value V2 of the digital signal D2L and outputs the ratio R to the SpO2 calculation unit 34. A smaller ratio between the voltage value V1 of the digital signal D1L and the voltage value V2 of the digital signal D2L means that the blood oxygen saturation level is higher.

  The SpO2 calculation unit 34 obtains the blood oxygen saturation concentration based on the correspondence table of the ratio R and blood oxygen saturation concentration prepared in advance and outputs the blood oxygen saturation concentration to the display unit 400. The correspondence table can be obtained in advance by an actual machine experiment or simulation.

  As described above, according to the biological information sensor 4 according to the fourth embodiment, the blood oxygen saturation concentration can be measured while the infrared light removal layer is provided. That is, according to the biological information sensor 4, the blood oxygen saturation concentration is measured while removing infrared light that becomes noise in measuring the heart rate by the infrared light removal layer to improve the measurement accuracy of the heart rate measurement. You can also.

  In the fourth embodiment, the case where an infrared cut filter is included in the infrared light removal layer has been described. The infrared light removal layer for measuring the blood oxygen saturation concentration is not limited to the case including an infrared cut filter. The infrared light removal layer in the case of measuring the blood oxygen saturation concentration can include, for example, an infrared cut resin as in the second embodiment, or infrared as in the third embodiment. A cut filter and an infrared cut resin can be included.

  In the first to fourth embodiments, the light emitting unit 10 that emits white light is used. However, since only green light and red light among white light is used, the light emitting unit 10 is replaced with green light. A green LED that emits light and a red LED that emits red light may be provided.

  In the first to fourth embodiments, one light emitting unit 10 and one light receiving unit 11 are used, but a plurality of light emitting units 10 and one light receiving unit 11 are used. In addition, one light receiving unit 11 may be provided at the center of the plurality of light emitting units 10.

  In the first to fourth embodiments, the infrared light removal layer is bonded to the silicon substrate 12. The infrared light removing layer is not necessarily bonded to the silicon substrate 12, and may be formed anywhere as long as it is located on the optical path to the photodiode 111A and located on the optical path to the photodiode 112A. Absent. For example, it may be formed inside the G sensor 111 and the R sensor 112 which are optical sensors, or may be formed at a position away from the silicon substrate 12.

  The infrared light removal layer includes not only the infrared cut filter and the infrared cut resin. Any material that can remove infrared light can be included in the infrared light removal layer.

  In the first embodiment, the second embodiment, and the fourth embodiment, the case where there is one infrared light removal layer will be described, and in the third embodiment, infrared light removal will be described. The case where the number of layers is two has been described. The infrared light removal layer is not limited to these cases and may be three or more layers.

  In the first to fourth embodiments, the infrared light is removed from the light incident on the light receiving unit by the infrared light removing layer. It can be said that infrared light is removed not only by an infrared light removal layer containing, for example, an infrared cut filter or an infrared cut resin, but also by a color filter that transmits light of a predetermined wavelength. It can be said that the infrared light removal layer in the present invention further enhances the removal of infrared light which has been performed by the color filter.

  Needless to say, according to the biological information sensor according to the embodiment, it is possible to detect the heart rate or blood oxygen saturation concentration of not only a human body but also a living body including humans and animals.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1, 2, 3, 4 Biological information sensor, 10 Light emitting unit, 11 Light receiving unit, 12 Silicon substrate, 12A Upper layer, 12B Lower layer, 13, 14 Shading wall, 15, 16 Lens, 17 Transparent plate, 18 substrate, 30 Calculation unit , 31, 32 Amplitude extraction unit, 33 Signal ratio calculation unit, 34 SpO2 calculation unit, 50 human body, 101 infrared cut filter, 102 infrared cut resin, 111 G sensor, 112 R sensor, 111 A, 112 A photodiode, 111 B G Filter, 112BR filter, 200,300 arithmetic control unit, 310 control unit, 311, 321 amplifier, 312, 322 AD converter, 313, 323 high-pass filter, 314, 324 low-pass filter, 400 display unit, D1, D1L, D2L, D2 digital signals, S0, S1, S2, S4 12 signal, V1, V2 voltage value.

Claims (13)

A biological information sensor that includes a light receiving unit and generates information related to a living body based on a signal from the light receiving unit;
The light receiving unit includes a first photosensor that converts first light into a first signal;
The first photosensor is
A first photoelectric conversion element that converts the first light into the first signal;
A first color filter formed on an optical path to the first photoelectric conversion element and transmitting the first light;
The biological information sensor further includes an infrared light removal layer formed on an optical path to the first photoelectric conversion element. An arithmetic control unit that generates information about the living body based on a signal from the light receiving unit;
The light receiving unit further includes a second photosensor that converts the second light into a second signal;
The second photosensor is
A second photoelectric conversion element that converts the second light into the second signal;
A second color filter that is formed on an optical path to the second photoelectric conversion element and transmits the second light;
The infrared light removal layer is also formed on the optical path to the second photoelectric conversion element,
The arithmetic control unit receives the first signal and the second signal from the light receiving unit, and generates information about the living body based on the first signal and the second signal. The biological information sensor according to 1. The light receiving unit further includes a first substrate on which the first photosensor and the second photosensor are formed,
The biological information sensor according to claim 2, wherein the infrared light removal layer is formed on a surface of the first substrate. The infrared light removal layer includes an infrared cut filter,
The biological information sensor according to claim 3, wherein the infrared cut filter covers the first color filter and the second color filter. The infrared light removal layer includes an infrared cut resin,
The biological information sensor according to claim 3, wherein the infrared cut resin covers the first substrate. The infrared light removal layer includes an infrared cut filter and an infrared cut resin,
The infrared cut filter covers the first color filter and the second color filter,
The biological information sensor according to claim 3, wherein the infrared cut resin is laminated on the infrared cut filter and covers the first substrate. A light emitting unit that emits light including the first light and the second light;
A second substrate on which the light emitting unit, the light receiving unit, and the calculation control unit are formed;
A first light shielding wall formed so as to surround the light emitting unit and the light receiving unit along an outer periphery of the second substrate;
A second light shielding wall that divides the space formed by the second substrate and the first light shielding wall into a space on the side where the light emitting part is located and a space on the side where the light receiving part is located;
The biological information sensor according to claim 2, wherein when the biological information sensor is attached to a living body, light reflected from the living body out of the light enters the light receiving unit.   The biological information sensor according to claim 7, wherein the light emitting unit is a light emitting diode that emits white light. The first light is green light;
The biological information sensor according to claim 2, wherein the second light is red light.   The biological information sensor according to claim 2, wherein the arithmetic control unit generates information related to the living body based on a difference between a level of the first signal and a level of the second signal.   The biological information sensor according to claim 10, wherein the information related to the living body is a heart rate.   The biological information sensor according to claim 2, wherein the arithmetic control unit generates information related to the living body based on a ratio between the level of the first signal and the level of the second signal.   The biological information sensor according to claim 12, wherein the information related to the living body is a blood oxygen saturation concentration.

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