JP2011045458A - Biological information detecting method, biological information detecting device, and human body-worn device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biological information detecting method, a biological information detecting device, and a human body-worn device for accurately measuring biological signals such as a pulse wave without generating individual differences by a tone of a skin color. <P>SOLUTION: The density of melanin pigments contained inside a skin H of an observed person is measured by applying observation light of a predetermined amount of luminescence to the skin H by a light emitting device 6a and by receiving the observation light scattered in the skin H by a light receiving element 9a which controls light receiving sensitivity. In addition, at least one of the amount of luminescence of the light emitting device 6a and the light receiving sensitivity of the light receiving element 9a is controlled by a CPU 37 in accordance with the measured density of the melanin pigments, and biological information corresponding to the density of the melanin pigments is detected based on a control result which has been controlled. Thus, since skin tissues such as the pulse wave are measured in accordance with the tone of the skin color of the observed person, the biological information such as the pulse wave is accurately ensured without generating individual differences by the tone of the skin color. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a biological information detection method, a biological information detection device, and a human body wearing device that optically measure a living body such as a pulse wave of a human body.

  As described in Patent Document 1, a conventional wristwatch-type biological information detection device has a light-emitting element that emits observation light of a predetermined wavelength on the back cover of a wristwatch, and is emitted by the light-emitting element and scattered by a living body. A light-receiving element that receives the observed light, and intermittently emits light from the light-emitting element at a constant cycle for a certain period of time. In addition, a signal obtained by performing frequency analysis on a signal obtained by continuously observing for a predetermined time and measuring biological information such as a pulse wave is known.

JP 2001-353133 A

  However, in such a conventional biological information detection device, the light emitting element emits light intermittently at a constant period for a certain period of time, and scattered light from the living body corresponding to the pulsed light emission of this light emitting element is received by the light receiving element and subjected to photoelectric conversion. However, since the photoelectrically converted signal is subjected to frequency analysis to measure biological information such as a pulse wave, there is a problem that a difference occurs in the measured value depending on the color depth of the skin.

  In other words, the human skin consists of the epidermis containing the melanin pigment on the surface side, the dermis containing the capillaries on which pulse waves are to be observed, and the subcutaneous tissue located inside the dermis. The density of the melanin pigment varies depending on the skin color depth, and the darker the skin, the more melanin pigment is contained in the epidermis. Light is absorbed.

  For this reason, in the conventional biological information detection device, even if the observation light is intermittently irradiated to the skin at a constant cycle for a certain period of time by the light emitting element, the person with dark skin reaches the dermis including the capillaries and reaches the dermis tissue The observation light that repeatedly scatters and absorbs in the light, passes through the epidermis again, and reaches the light receiving element is weak, and the measured light cannot be received by the light receiving element sufficiently. The biometric information such as a pulse wave cannot be accurately measured according to the color depth of the skin.

  Problems to be solved by the present invention are a biological information detection method, a biological information detection apparatus, and a human body-mounted device capable of accurately measuring a living body such as a pulse wave without causing individual differences depending on the color of skin. Is to provide.

In order to solve the above problems, the present invention includes the following components.
The invention according to claim 1 irradiates the skin by irradiating observation light of a specific wavelength band with light of a predetermined emission amount in order to optically observe the skin tissue of the human body by a light emitting element, A first step of measuring the density of the melanin pigment contained in the skin by receiving the irradiation light that has been irradiated and scattered in the skin with a light receiving element whose light sensitivity can be controlled; and Based on the measurement result measured in the first step, a second step for controlling at least one of the light emission amount of the light emitting element and the light receiving sensitivity of the light receiving element, and the control controlled by the second step And a biological information detecting step of detecting biological information corresponding to the density of the melanin pigment based on the result.

  According to a second aspect of the present invention, in order to optically observe a living body with a light emitting element, observation light in a specific wavelength band is emitted with a predetermined amount of light to irradiate the living body. The first step of measuring the state of the living body by receiving the scattered light of the observation light scattered in the living body with a light receiving element whose light receiving sensitivity is controllable, and the measurement result measured by the first step Based on the second step of controlling at least one of the light emission amount of the light emitting element and the light receiving sensitivity of the light receiving element, and based on the control result controlled by the second step, the state of the living body is determined. And a biological information detecting step for detecting biological information to be shown.

  According to a third aspect of the present invention, the first step includes an irradiation step in which the observation light is emitted by the light emitting element at a predetermined number of times with different light emission amounts and irradiated to the skin. A light receiving step for receiving each of the observation lights irradiated and scattered in the skin by the light receiving element, and measuring a density of the melanin contained in the skin based on the scattered light received by the light receiving step. The biological information detecting method according to claim 1, further comprising: a density measuring step.

  According to a fourth aspect of the present invention, in the second step, the amount of light emitted from the light emitting element and the light receiving sensitivity of the light receiving element are determined based on the measurement result of the first step. The biological information detection method according to claim 1, further comprising an observation step that is set so as to correspond to any of the above, and observes the skin tissue.

  According to a fifth aspect of the present invention, there is provided an observation light irradiating means for irradiating the skin by emitting observation light of a specific wavelength band by a light emitting element in order to optically observe a human skin tissue. The observation light irradiated by and scattered in the skin is received by a light receiving element, converted into an electrical signal and output, and the light emitting element emits light with a predetermined light emission amount, The emitted observation light is received by the light receiving element, the density of the melanin pigment contained in the skin is measured according to the amount of the received light, and the light emission amount of the light emitting element and the light reception are measured based on the measurement result. Control means for controlling at least one of the light receiving sensitivity of the element, and biological information detection means for detecting biological information corresponding to the density of the melanin pigment based on a control result controlled by the control means; That it comprises a a biological information detection apparatus according to claim.

  According to a sixth aspect of the present invention, in order to optically observe a living body by a light emitting element, observation light in a specific wavelength band is emitted with light having a predetermined light emission amount to irradiate the living body. Receiving the scattered light of the observation light scattered in the living body with a light receiving element whose light receiving sensitivity can be controlled, and measuring means for measuring the state of the living body, based on the measurement result measured by the measuring means, Control means for controlling at least one of the light emission amount of the light emitting element and the light receiving sensitivity of the light receiving element, and biological information for detecting biological information indicating the state of the living body based on a control result controlled by the control means A biological information detecting method comprising: a detecting means;

  According to a seventh aspect of the present invention, the measurement means causes the light emitting element to emit light a predetermined number of times with different light emission amounts to irradiate the skin, and the observation light that has been irradiated and scattered within the skin. Are received by the light receiving element, and density measuring means for measuring the density of the melanin pigment contained in the skin according to the amount of received light is provided, and the control means is responsive to the measurement result by the measuring means. A determination unit that determines which of the plurality of levels of the skin type, and at least one of a light emission amount of the light emitting element and a light receiving sensitivity of the light receiving element based on a determination result by the determination unit The living body information detecting apparatus according to claim 5, further comprising: an observation unit configured to observe each of the skin tissues by setting each of the skin types so as to correspond to any one of the skin types.

  The invention described in claim 8 is a human body mounting device characterized in that the biological information detecting device according to claim 5 or 6 is provided in a device main body mounted on the human body.

  According to the present invention, the observation light is irradiated onto the skin with a predetermined amount of light emitted by the light emitting element, and the observation light scattered in the skin is received by the light receiving element whose light receiving sensitivity can be controlled. The density of the melanin pigment contained in the skin of the observer can be measured, and at least one of the light emission amount of the light emitting element and the light receiving sensitivity of the light receiving element can be controlled according to the measured density of the melanin pigment . For this reason, a skin tissue such as a pulse wave can be measured according to the darkness of the color of the observer's skin. For this reason, it is possible to accurately measure a biological signal such as a pulse wave without causing individual differences depending on the darkness of the skin color.

  In addition, according to the present invention, in order to optically observe the living body with the light emitting element, the observation light in the specific wavelength band is emitted with the light having a predetermined light emission amount to irradiate the living body. The scattered light of the observation light scattered in the living body is received by a light receiving element whose photosensitivity can be controlled, the state of the living body is measured, and based on the measured result, the amount of light emitted from the light emitting element and After controlling at least one of the light receiving sensitivity of the light receiving element, it is possible to detect biological information indicating the state of the living body based on the controlled result. For this reason, highly accurate biological information can be ensured reliably.

It is an expanded sectional view showing one embodiment of a wristwatch to which the present invention is applied. It is the enlarged plan view which showed the back cover of the wristwatch of FIG. It is an expanded sectional view in the AA arrow of FIG. FIG. 4 is an enlarged cross-sectional view showing a state in which a living body information detecting device of FIG. 3 is brought into contact with the skin of an arm and a living body such as a pulse wave is optically measured. FIG. 5 is an enlarged cross-sectional view of a main part schematically showing the skin of FIG. 4 enlarged. It is the block diagram which showed the circuit structure of the biometric information detection apparatus of FIG. It is the figure which showed the main absorption spectrum of the biological component in the skin of FIG. It is the figure which classified the skin type into 6 steps according to the density of the melanin contained in the skin of FIG. FIG. 9 is a diagram showing the amount of light received by the light receiving element with respect to the driving current of the light emitting element in FIG. FIG. 10 is a diagram illustrating a relationship between a light receiving current of the light receiving element and an input signal (input voltage) of the A / D converter in FIG. 9. It is the figure of Table 1 which showed each voltage value given to the voltage (Vout1) of a 1st D / A converter, and the voltage (Vout2) of a 2nd D / A converter in order to confirm the skin type of FIG. FIG. 12 is a table 2 showing voltage values given to the voltage (Vout1) of the first D / A converter and the voltage (Vout2) of the second D / A converter in order to observe the pulse wave in the skin type of FIG. FIG. 6 is an enlarged cross-sectional view of the irradiation state of observation light when the density of the melanin pigment contained in the skin in FIG. 5 is low and the light emitting element emits light with a predetermined light emission amount. FIG. 14 is an enlarged cross-sectional view of the observation light irradiation state in the case where the density of the melanin pigment contained in the skin in FIG. FIG. 15 is an enlarged cross-sectional view of the observation light irradiation state in the case where the density of the melanin pigment contained in the skin in FIG. 14 is high and both the light emission amount by the light emitting element and the light receiving sensitivity of the light receiving element are adjusted. It is the figure which showed the basic operation | movement flow in the biometric information detection apparatus of FIG. It is the figure which showed the operation | movement flow of the skin type confirmation process which confirms the skin type of FIG. It is the figure which showed the operation | movement flow of the pulse wave observation process which observes the pulse wave of FIG.

Hereinafter, an embodiment in which the present invention is applied to a wristwatch will be described with reference to FIGS.
As shown in FIG. 1, the wristwatch includes a wristwatch case 1. A watch glass 2 is attached to the upper opening of the watch case 1 via a packing 2a, and a back cover 3 is attached to the lower portion of the watch case 1 via a waterproof ring 3a. A watch module 4 having various parts necessary for the watch function is disposed inside the watch case 1.

  Further, as shown in FIGS. 1 to 3, a biological information detecting device 5 is provided at the center of the back cover 3 of the wristwatch case 1. In this case, the back cover 3 is made of a metal such as stainless steel, and as shown in FIGS. 3 and 4, the lower surface of the back cover 3 protrudes downward while gently curving toward the center. An attachment hole 3b for attaching the biological information detection device 5 is provided in the protruding central portion so as to penetrate vertically.

  As shown in FIGS. 3 and 4, the biological information detection device 5 includes a light emitting unit 6 that emits observation light in a specific wavelength band in order to optically observe the skin of the human body, and an observation in which the light emitting unit 6 emits light. A light guide member 7 that guides light and diffuses and irradiates the skin H in a ring shape, and an observation light capturing unit 8 that contacts the skin H located in the center of the annular irradiation region E irradiated by the light guide member 7. And a light receiving unit 9 that is arranged at a position on the opposite side of the skin H in the observation light capturing unit 8 and receives the observation light captured by the observation light capturing unit 8.

  In this case, the light emitting unit 6 and the light receiving unit 9 are provided on the lower surface of the circuit board 10 for measurement, as shown in FIGS. The circuit board 10 is located in the upper part of the light guide member 7 and is disposed in the watch case 1. The lower portion of the light guide member 7 is fitted into the mounting hole 3 b of the back cover 3, and the upper portion thereof is disposed on the lower surface of the circuit board 10 in the watch case 1.

  By the way, the light emitting unit 6 is of a side emission type, and has a configuration in which a light emitting element 6a such as a light emitting diode (LED) is provided on the side surface of the element substrate 6b. This light emitting element 6a is configured to emit λp = 940 nm infrared light having a low absorbance, which is absorbed by the melanin pigment contained in the skin H, as observation light. As shown in FIGS. 3 and 4, the light emitting unit 6 corresponds to 4 directions at 12 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock on the lower surface of the circuit board 10 corresponding to the outer periphery of the light guide member 7. It is provided at each location.

  As shown in FIGS. 3 and 4, the light guide member 7 includes a light guide ring portion 11, a diffuse reflection ring portion 12, a diffusion ring portion 13, and a diffusion irradiation ring portion 14. The light guide ring portion 11 is made of a material such as a transparent resin having high light transmittance or transparent glass, and is formed in a substantially square flat plate shape as a whole. The light guide ring part 11 has a configuration in which a circular hole 11a is formed in the center part and an incident surface 11b in which the light emitting part 6 is arranged corresponding to each corner part.

  In this case, the light guide ring portion 11 is disposed on the lower surface of the circuit board 10 so that the incident surface 11b at each corner corresponds to four directions of 12:00, 3 o'clock, 6 o'clock, and 9 o'clock. That is, as shown in FIG. 2, the incident surface 11b of the light guide ring portion 11 is a notch recess formed by biting into each corner of the light guide ring portion 11 in a semicircular shape. The light emitting element 6a of the light emitting unit 6 is disposed in the recess. Thereby, the light guide ring part 11 is configured such that the observation light emitted from the light emitting element 6a is incident radially from four directions from the four corners of the light guide ring part 11 toward the circular hole 11a in the central part. ing.

  In addition, the light guide ring portion 11 has an inner peripheral surface of a circular hole 11a at the center portion formed on the emission surface 11c. Thereby, as shown in FIG. 4, the light guide ring unit 11 takes the observation light emitted by the light emitting unit 6 into the inside from the incident surface 11 b at each corner in the four directions. The light is guided from the direction toward the central circular hole 11a, and the guided observation light is emitted from the emission surface 11c which is the inner peripheral surface of the circular hole 11a.

  In this case, on the outer surface of the light guide ring portion 11, as shown in FIG. 3 and FIG. 4, the light guide except for the entrance surface 11b at each corner and the exit surface 11c which is the inner peripheral surface of the circular hole 11a. A first reflective layer 15 for preventing observation light incident on the inside of the ring portion 11 from leaking to the outside of the light guide ring portion 11 is provided by metal deposition such as aluminum or plating.

  Further, as shown in FIGS. 3 and 4, the diffuse reflection ring portion 12 is made of a synthetic resin such as a white turbid or milky white acrylic resin having light diffusibility, and is formed in a substantially circular ring shape as a whole. The diffuse reflection ring portion 12 has a thickness that is substantially the same as that of the introduction ring portion 11, and is disposed in the circular hole 11 a of the light guide ring portion 11. In this case, the outer peripheral surface of the diffuse reflection ring portion 12 is formed on the incident surface 12 a, and the incident surface 12 a is disposed in close contact with the emission surface 11 c which is the inner peripheral surface of the circular hole 11 a of the light guide ring portion 11. It is comprised so that.

  Further, as shown in FIGS. 3 and 4, the lower surface of the diffuse reflection ring portion 12 is formed on an emission surface 12 b that emits observation light taken from the incident surface 12 a on the outer peripheral surface toward the skin H. Yes. Further, a reflection surface 12c that reflects the observation light taken from the incident surface 12a on the outer peripheral surface toward the emission surface 12b on the lower surface is continuously formed in an annular shape on the inner peripheral portion of the diffuse reflection ring portion 12. ing. The reflecting surface 12c is formed on a part of the inverted conical surface, that is, a part of the inverted conical surface that tapers downward.

  Further, as shown in FIGS. 3 and 4, the outer surface of the diffuse reflection ring portion 12 is incident on the inside of the diffuse reflection ring portion 12 except for the incident surface 12 a on the outer peripheral surface and the exit surface 12 b on the lower surface. A second reflection layer 16 for preventing observation light from leaking out of the diffuse reflection ring portion 12 and for optically separating the light receiving portion 9 described later is provided by metal deposition such as aluminum or plating.

  As a result, the diffuse reflection ring unit 12 takes the observation light emitted from the emission surface 11c, which is the inner circumferential surface of the light guide ring unit 11, from the incident surface 12a on the outer circumferential surface, and the taken observation light is used. While diffusing while being guided along the annular shape of the diffuse reflection ring portion 12, the reflection surface 12c provided on the inner peripheral portion reflects the light toward the lower emission surface 12b, and the diffusely reflected observation light is reflected on the lower emission surface. It is comprised so that it may discharge | release below from 12b.

  As shown in FIGS. 3 and 4, the diffusion ring portion 13 is made of a synthetic resin having light diffusibility, and is formed in a substantially circular ring shape as a whole. The diffusion ring portion 13 is formed in a thin sheet shape, and is disposed in close contact with the emission surface 12 b on the lower surface of the diffuse reflection ring portion 12. Similarly to the diffusive reflection ring unit 12, the incident observation light is prevented from leaking to the outside of the diffusing ring unit 13 on each of the outer peripheral surface and the inner peripheral surface of the diffusing ring unit 13, and the light receiving unit 9 described later. The second reflective layer 16 is optically separated from each other by metal deposition such as aluminum or plating.

  Thereby, as shown in FIGS. 3 and 4, the diffusing ring portion 13 takes the observation light emitted from the emission surface 12b of the diffusive reflection ring portion 12 from the upper surface, and diffuses the taken observation light. The light is sufficiently diffused so as to be uniform while being guided along the ring of the ring portion 13, and the diffused observation light is uniformly emitted from the lower surface toward the skin H without any spots.

  As shown in FIGS. 3 and 4, the diffusion irradiation ring portion 14 is made of a synthetic resin such as an acrylic resin having a diffusibility, and is formed in a substantially circular ring shape as a whole. The diffuse irradiation ring portion 14 is disposed below the diffuse reflection ring portion 12 via the diffusion ring portion 13, and is fitted into the attachment hole 3 b of the back cover 3 via the first waterproof packing 17. In this case, the outer periphery of the diffuse irradiation ring portion 14 is slightly larger than the outer periphery of the diffuse reflection ring portion 12, and the inner periphery is slightly smaller than the inner periphery of the diffuse reflection ring portion 12.

  Thereby, the diffusion irradiation ring part 14 takes in the observation light emitted from the diffuse reflection ring part 12 and diffused in a ring shape without any spots in the diffusion ring part 13 from the upper surface, and further diffuses the taken observation light, The diffused observation light is emitted from the lower surface in a ring shape so that the observation light is uniformly diffused and irradiated onto the skin H over a wide ring-shaped area.

  Also in this case, the observation light incident on the inside of the diffusion irradiation ring portion 14 is formed on the outer peripheral surface and the inner peripheral surface of the diffusion irradiation ring portion 14 except for the upper and lower surfaces thereof as shown in FIGS. Is prevented from leaking out of the diffusion irradiation ring portion 14, and a third reflective layer 18 for optically separating the light receiving portion 9 described later is provided by metal deposition such as aluminum or plating.

  Further, the position of the diffusing irradiation ring portion 14 is regulated so as not to be pushed into the wristwatch case 1 by abutting against the protruding portion 3 c provided in the mounting hole 3 b of the back cover 3. In this case, as shown in FIG. 3 and FIG. 4, the lower surface of the diffusion irradiation ring portion 14 is arranged at the same height as the lowermost portion of the lower surface of the back cover 3, thereby The lower surface of the lid 3 is configured to come into contact with the skin H together with the lower surface of the back lid 3 without causing a step.

  As shown in FIGS. 3 and 4, an observation light capturing unit 8 for capturing the observation light irradiated into the skin H is provided inside the diffusion irradiation ring unit 14. The observation light collection unit 8 is made of a material such as a transparent resin having a high refractive index or transparent glass, and is formed in a circular flat plate shape as a whole. In this case, the observation light taking-in part 8 is formed to have the same thickness as that of the diffusion irradiation ring part 14. Thereby, each upper surface and each lower surface of observation light taking-in part 8 and diffused irradiation ring part 14 are arranged on substantially the same plane.

  In addition, as shown in FIGS. 3 and 4, the observation light capturing unit 8 includes a diffusion irradiation ring unit via a second waterproof packing 19 between the outer peripheral surface and the inner peripheral surface of the diffusion irradiation ring unit 14. 14 is attached. The observation light collection unit 8 is configured such that the lower surface thereof is in contact with the skin H located at the center of the ring-shaped irradiation region E irradiated by the diffusion irradiation ring unit 14. Thereby, the observation light taking unit 8 is configured to take the observation light irradiated into the skin H from the lower surface and irradiate the taken scattered light from the upper surface toward the light receiving unit 9.

  The light receiving unit 9 receives the observation light taken in by the observation light taking unit 8 and photoelectrically converts it, and has a configuration in which a light receiving element 9a such as a silicon photodiode is provided downward on the lower surface of the element substrate 9b. ing. As shown in FIGS. 3 and 4, the light receiving unit 9 is disposed on the side opposite to the skin H (upward in FIG. 3) in the observation light capturing unit 8 in a state where the light receiving element 9 a is housed in the holder unit 21. It is provided on the lower surface of the circuit board 10 at a position where it is located, that is, at a position located near the focal position on the optical axis of the observation light capturing unit 8.

  The light receiving element 9a of the light receiving unit 9 has a spectral sensitivity characteristic that reacts most strongly to light in a specific wavelength band having a wavelength (λ) of about 940 nm. That is, the light receiving element 9a gradually decreases the light receiving sensitivity with respect to light in the wavelength band of 940 nm or less, and conversely converts it to light in the wavelength band of about 940 nm or more. On the other hand, the light receiving sensitivity is drastically lowered, and the light receiving sensitivity is highest for light having a wavelength of 940 nm.

  As shown in FIGS. 3 and 4, the optical filter 20 is positioned below the light receiving element 9a, that is, between the light receiving element 9a and the observation light receiving unit 8, as shown in FIGS. Arranged in the portion 21. The optical filter 20 transmits light in a specific wavelength band having a wavelength of 900 nm or more and blocks light in a wavelength band having a wavelength of 900 nm or less, so that the light receiving element 9a is affected by measurement fluctuation due to external light such as sunlight. Is configured to mitigate.

  In this case, the holder portion 21 of the light receiving portion 9 is made of a light-shielding metal such as aluminum, and the surface thereof is subjected to alumite treatment having a reflection function, thereby optically protecting the light receiving element 9a. Has been. As shown in FIGS. 3 and 4, the holder portion 21 is formed with the same thickness as the light emitting portion 6 (length in the vertical direction), and is disposed in the central portion of the diffuse reflection ring portion 12.

  Thereby, the light emitting part 6, the light guide ring part 11, the diffuse reflection ring part 12, and the light receiving part 9 are formed within the thickness of the light emitting part 6 (length in the vertical direction). Are arranged on substantially the same plane, and in this state, the whole is arranged in a plane with a thickness of about 1 mm. Further, the optical filter 20 is formed so that the thickness thereof is substantially the same as that of the diffusion ring portion 13, and is arranged on the same plane as the inner surface (upper surface in FIG. 3) of the back cover 3 together with the diffusion ring portion 13. Has been.

Next, the circuit configuration of the biological information detection apparatus 5 will be described with reference to the block diagram shown in FIG.
The circuit configuration of the biological information detecting device 5 includes a control device 25, a photoelectric signal detecting unit 26 having a light emitting element 6a and a light receiving element 9a, and a light emitting unit driving circuit 27 for driving the light emitting element 6a of the photoelectric signal detecting unit 26. And a light emission control circuit 28 for controlling the light emission amount of the light emitting element 6a driven by the light emitting unit drive circuit 27.

  Further, as shown in FIG. 6, the circuit configuration of the biological information detection device 5 converts a current signal (light reception current Ipd) output from the light receiving element 9a of the photoelectric signal detection unit 26 into a voltage signal (light reception voltage Vin). The I / V conversion circuit 29 for performing the operation, the reference voltage generation circuit 30 for applying the reference voltage (Vref1) to the I / V conversion circuit 29, and the output signal (light reception voltage Vin) from the I / V conversion circuit 29 are captured. And a light receiving control circuit 31 for controlling the light receiving sensitivity of the light receiving element 9a.

  Furthermore, the circuit configuration of the biological information detection device 5 includes a display unit 32 that displays biological measurement results such as pulse waves as biological information, a power source unit 33 that supplies power to each unit, and a switch that is input by the user. Part 34. The power supply unit 33 supplies power to the light emitting unit drive circuit 27, and also includes a control power supply circuit 35 that supplies power to the control device 25, an analog circuit such as a light emission control circuit 28, a reference voltage generation circuit 30, and a light reception control circuit 31. And an analog power supply circuit 36 for supplying power to the power supply.

  Incidentally, the control device 25 includes a CPU (Central Processing Unit) 37 that performs overall control of the circuit, a ROM (Read Only Memory) 38 in which a predetermined program is stored, and a RAM (Writable / Readable) as needed. A random access memory) 39, a time measuring circuit 40 for measuring time, a switch circuit 41 for outputting a switch signal in accordance with an operation of the switch unit 34, a display drive circuit 42 for driving the display unit 32, and an operation signal for each unit. And an IO port 43 for receiving an output signal from the light receiving control circuit 31, and these are connected to the CPU 37 by a bus line 44.

  The CPU 37 is an integrated circuit such as an LSI (Large Scale Integrated circuit). The photoelectric signal detecting unit 26 emits observation light in a specific wavelength band, and when the observation light emitted from the light emitting element 6a is irradiated on the skin H and scattered / absorbed in the skin H. And a light receiving element 9a for receiving the observation light and outputting a current signal (light reception current Ipd) according to the amount of light received. In this case, the light emitting elements 6a are arranged at four locations corresponding to four directions of 12 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock, and the four light emitting elements 6a are connected in series.

  The light emitting unit drive circuit 27 is a step-up power supply circuit that boosts the power supply voltage from the power supply unit 33 to a voltage necessary for driving the light emitting element 6a, and its input terminal EN is connected to the output terminal (OUT1) of the control device 25. Has been. The light emission control circuit 28 includes a first D / A converter 45 and a constant current circuit 46. The constant current circuit 46 includes an operational amplifier 46a, a transistor Tr, and a resistor Ra.

  The first D / A converter 45 has its control terminals (SYNCB, SCLK, DIN) connected to the output terminals (OUT2 to OUT4) of the control device 25, respectively, so that data communication with the control device 25 can be performed in a serial manner. It has become. The first D / A converter 45 has an output terminal (Vout1) connected to the operational amplifier 46a of the constant current circuit 46, and a resolution of 10 bits between the power supply voltage supplied from the analog power supply circuit 36 and the ground. The voltage is divided, and one of the divided voltages (Vout1) is supplied to the operational amplifier 46a.

  Thereby, the light emission current (If) flowing through the light emitting element 6a of the photoelectric signal detection unit 26 is obtained by dividing the voltage value (Vout1) output from the first D / A converter 45 by the resistance value (Ra) of the constant current circuit 46. Value (If = Vout1 / Ra). For this reason, the light emission current (If) flowing through the light emitting element 6a varies depending on the voltage value (Vout1) from the output terminal of the first D / A converter 45 due to the constant resistance Ra of the constant current circuit 46. The amount of light emitted by the light emitting element 6a of the photoelectric signal detector 26 is adjusted accordingly.

  On the other hand, the I / V conversion circuit 29 that converts the light reception current (Ipd) output from the light receiving element 9a of the photoelectric signal detection unit 26 into the light reception voltage (Vin) is composed of an operational amplifier 29a and a resistor Rf. The operational amplifier 29a is connected to the light receiving element 9a of the photoelectric signal detector 26 and the output terminal (Vout) of the reference voltage generation circuit 30. The light reception control circuit 31 includes a second D / A converter 47 and an A / D converter 48.

  The second D / A converter 47 has its control terminals (SYNCB, SCLK, DIN) connected to the output terminals (OUT5 to OUT7) of the control device 25, respectively, so that serial communication data communication with the control device 25 is possible. It has become. The A / D converter 48 has its control terminals (CSB, DCLK) connected to the output terminals (OUT8 to OUT9) of the control device 25, respectively, so that data communication with the control device 25 can be performed in a serial manner. .

  The A / D converter 48 has its input terminal (Vref2) connected to the output terminal (Vout2) of the second D / A converter 47, and supplied with a reference voltage (Vout2). The A / D converter 48 has an input terminal (Vin) connected to the output terminal of the I / V conversion circuit 29 and an output terminal (DOUT) connected to the input terminal (IN) of the control device 25. Has been.

  As a result, the A / D converter 48 gives the light reception voltage (Vin) generated in the light receiving element 9a of the photoelectric signal detection unit 26 and converted by the I / V conversion circuit 29 to the input terminal (Vin). The light reception voltage (Vin) applied to the A / D converter 48 is a product of the light reception current (Ipd) generated in the light receiving element 9 a of the photoelectric signal detection unit 26 and the resistance value (Rf) of the I / V conversion circuit 29. A value obtained by adding the reference voltage (Vref1) from the reference voltage generation circuit 30 (Vin = Ipd × Rf + Vref1).

  Further, the A / D converter 48 converts the light reception voltage (Vin) given from the I / V conversion circuit 29 based on the voltage between the voltage (Vref2) given from the second D / A converter 47 and the ground. A / D conversion is performed with 16 bits, and A / D converted data subjected to A / D conversion with 16 bits is supplied from the output terminal (DOUT) to the input terminal (IN) of the control device 25.

  As a result, the CPU 37 samples and holds the light reception signal level from the light receiving element 9a output from the A / D converter 48 to determine A / D conversion data. In this case, the CPU 37 stops the boosting operation in which the light emitting unit driving circuit 27 boosts the power supply voltage from the power supply unit 33 to a voltage necessary for driving the light emitting element 6a.

  The light emission amount of the light emitting element 6a is proportional to the drive current (If), and the resistance (Ra) of the constant current circuit 46 is constant (for example, Ra = 100Ω). Accordingly, the drive signal (Vout1) of the light emitting element 6a output from the output terminal (Vout1) of the first D / A converter 45 is controlled by the CPU 37 and the power supply voltage (VDDA) supplied to the first D / A converter 45. It is divided into 10 bits with respect to the ground, and this divided voltage signal is given to control the light emission amount of the light emitting element 6a.

  The light receiving element 9a emits light from the light emitting element 6a and irradiates the observation light to the skin H. The irradiated observation light is scattered and absorbed in the skin H, and receives the scattered light to generate a light receiving current (Ipd). appear. In this case, when the scattering condition of the skin H and the blood state are constant, the light receiving current (Ipd) generated in the light receiving element 9a differs depending on the type of the skin H. This type of skin H is classified by the density of melanin pigment contained in the epidermis H2 of the skin H.

  That is, as shown in FIG. 7, the absorption spectrum of the biological tissue component has high absorbance of hemoglobin HE and melanin dye ME at a wavelength of 600 nm or less. The epidermis H2 of the skin H contains a melanin pigment ME in order to protect tissues below the dermis H1 from harmful ultraviolet rays. The content density of the melanin ME varies greatly depending on the darkness of the skin color, and is classified into six stages of skin types 1 to 6 as shown in FIG.

  In FIG. 8, the skin types 1 to 6 when the skin types are classified into six stages, the content index of the melanin pigment corresponding thereto, and the observation light pass through the epidermis H2 for each skin type 1 to 6. The relationship with the transmittance is shown. Of skin types 1 to 6, skin type 2 is white skin, skin type 3 is yellow skin, and skin type 5 is black skin. In this case, the observation light is, for example, green light having a wavelength (λ) of 520 nm and near infrared light having a wavelength of 940 nm. Green light having a wavelength of 520 nm is hardly transmitted in the case of skin type 5 black skin, so that it can be seen that the use as observation light is inappropriate.

  In the case of near-infrared light having a wavelength of 940 nm, in the case of skin type 1 white skin where the density of the melanin pigment contained in the epidermis H2 is small, the observation light transmitted through the epidermis H2 and scattered inside the skin H Is transmitted through the skin H2 again and is received by the light receiving element 9a, but since the transmittance of the observation light is as high as about 99.3%, in both the light emitting part 6 and the light receiving part 9, the part of the skin H2 Since the absorption is negligible, as shown in FIG. 13, the observation light irradiated from the light emitting unit 6 and scattered inside the skin H and incident on the light receiving element 9a is mainly scattered within the depth range of the dermis H1. Can be limited to observation light.

  On the other hand, in the case of skin type 5 black skin where the density of melanin contained in the epidermis H2 is high, the transmittance of the epidermis H2 is about 46%, and it penetrates the epidermis H2 and is scattered inside the skin tissue. The observed light is also transmitted through the epidermis H2 again and received by the light receiving element 9a. Therefore, when the transmittance in the case of skin type 1 white skin is 100%, in the case of skin type 5 black skin, It will be about 20% (about 1/5).

  In the case of this skin type 5 black skin, in order to secure the amount of light received by the light receiving element 9a, the light emission amount is increased by adjusting only the light emitting element 6a under the condition that the light receiving sensitivity is kept at the skin type 1. As shown in FIG. 14, the observation light from the light emitting element 6a is deeply irradiated to the subcutaneous tissue below the dermis H1, and other than the blood pulsation signal in the dermis H1 (that is, the pulsation signal associated with the pulsation of the heart). It becomes easy to be influenced by noise (for example, pulsation accompanying body movement).

  Therefore, in this biological information detection device 5, in the skin type 5 black skin using near-infrared light having a wavelength of 940 nm, the amount of light received by the light receiving element 9a is set to be the same as that of the skin type 1 white skin. By increasing the light emission amount of the light emitting element 6a by about 5 times and increasing the light receiving sensitivity of the light receiving element 9a to the same extent, as shown in FIG. 15, the observation light is irradiated only to the dermis H1 and received. The element 9a is configured to sufficiently receive the observation light.

  As a result, the light receiving current (Ipd) generated by being received by the light receiving element 9a is obtained for each skin type 1 to 5 as shown in FIG. 9 when the scattering condition of the skin H and the blood state are constant. It increases in proportion to the amount of light received. That is, the light reception current (Ipd) generated in the light receiving element 9a is given as an output voltage (Vin) from the operational amplifier 29a of the I / V conversion circuit 29 to the A / D converter 48.

  The output voltage (Vin) given to the A / D converter 48 is the product of the light receiving current (Ipd) generated in the light receiving element 9a of the photoelectric signal detection unit 26 and the resistance value (Rf) of the I / V conversion circuit 29. Since it is a value (Vin = Ipd × Rf + Vref1) to which the reference voltage (Vref1) of the reference voltage generating circuit 30 is added, as shown in FIG. 10, the reference voltage (Vref1) is used as a contact point, and the slope is an I / V conversion circuit. It is represented by a straight line of 29 resistance values (Rf).

  In this case, the reference potential (Vref2) supplied to the A / D converter 48 is controlled by the CPU 37 and output from the output terminal (Vout2) of the second D / A converter 47. The input voltage (VDDA) and the ground are divided with an 8-bit resolution, and the divided voltage signal (Vout2) is output. The A / D converter 48 has a 16-bit resolution between the reference potential (Vref2) based on the output voltage (Vout2) from the second D / A converter 47 and the ground, and outputs the output voltage from the I / V conversion circuit 29 ( Vin) is A / D converted.

  Accordingly, by controlling the light emission amount of the light emitting element 6a and the light reception amount of the light receiving element 9a according to the skin type 1 to 6 of the measurer, the skin type 1 to 6 of the measurer and the skin types 1 to 6 thereof are controlled. The corresponding living tissue can be observed. Accordingly, each voltage for controlling the light emission amount of the light emitting element 6a and the light reception amount of the light receiving element 9a, that is, the output voltage (Vout1) of the first D / A converter 45 and the output voltage (Vout2) of the second D / A converter 47. 11 and 12 are set as reference data corresponding to the skin type 1 to 6 of the measurer and registered in the RAM 39 in advance.

  That is, the reference data of Table 1 shown in FIG. 11 includes the output voltage (Vout1) of the first D / A converter 45 and the output voltage of the second D / A converter 47 for measuring the skin types 1 to 6 of the measurer. Reference data (Vout2) is registered in the table 1 of the RAM 39. 12 includes the output voltage (Vout1) of the first D / A converter 45 for observing the living tissue corresponding to the skin types 1 to 6 and the second D / A converter 47. Reference data for the output voltage (Vout2), which is registered in the table 2 of the RAM 39.

Next, with reference to FIG. 16, a basic operation flow of a biological tissue observation process for observing a biological tissue by the biological information detection device 5 will be described.
When the operation of the biological tissue observation process starts, the CPU 37 emits observation light in a specific wavelength band with light of a predetermined light emission amount in order to optically observe the human skin tissue by the light emitting element 6a. The density of the melanin pigment contained in the skin H is measured by irradiating the skin H and receiving the irradiated light scattered in the skin H by the light receiving element 9a whose light receiving sensitivity can be controlled. The skin type of the observer is confirmed (step S1). Thereafter, based on the measurement result measured in step S1, the pulse wave is observed by controlling the light emission amount of the light emitting element 6a and the light receiving sensitivity of the light receiving element 9a (step S2), and this operation is finished.

Next, with reference to FIG. 17, the operation flow of the skin type confirmation process for confirming the skin type of the observer shown in step S1 of FIG. 16 will be described.
When the operation of the skin type confirmation process starts, the CPU 37 reads the contents of the table 1 registered in the RAM 39 and outputs it from the output terminal (Vout2) of the second D / A converter 47 based on the contents of the table 1. The voltage corresponding to the skin type 2 (Vref2 = 2.048 mV) is applied to the A / D converter 48, and the light receiving sensitivity of the light receiving element 9a is set to the light receiving sensitivity of the skin type 2 (step S11). .

  Thereafter, the CPU 37 updates the output voltage (Vout1) of the first D / A converter 45 to the skin type 2 based on the contents of the table 1 (step S12), and the output voltage (Vout1) of the first D / A converter 45 is updated. The voltage (Vout1 = 105.0 mV) close to the voltage of skin type 2 (Vout1 = 104.6 mV) is set to light up the light emitting element 6a with a light emission amount corresponding to the skin type 2 (step S13).

  Then, the observation light emitted from the light emitting element 6a is applied to the skin H of the observer, the irradiated observation light is scattered and absorbed in the skin H, and the observation light scattered in the skin H is received by the light receiving element. The light is received by 9a. Thereby, in the light receiving element 9a, a light receiving current (Ipd) is generated in the light receiving element 9a according to the amount of light received. The generated light receiving current (Ipd) is given to the input terminal (Vin) of the A / D converter 48 as a voltage signal by the I / V conversion circuit 29.

  The voltage signal input to the input terminal (Vin) is converted into a corresponding digital light reception voltage value (AD0) by the A / D converter 48 (step S14). The CPU 37 determines whether or not the converted light reception voltage value (AD0) is larger than a predetermined reference value (AD reference value) (step S15). At this time, when the received light voltage value (AD0) is larger than the reference value, it is determined that the density of the melanin pigment contained in the skin H of the measurer is lower than the skin type 2, and the measurer takes the skin type 1 (Step S16), and the process returns to the main flow.

  If the received light voltage value (AD0) is smaller than the reference value in step S15, it is determined that the density of the melanin contained in the skin H of the measurer is higher than the skin type 2, and the skin type is determined. Step 1 is advanced (step S17), and it is determined whether the raised skin type is the sixth step skin type 6 (step S18). If not the sixth step, skin type 6 is returned to step S12. Steps S12 to S18 are repeated from skin type 3 to skin type 6.

  That is, when the skin type is moved up by one step in step S17 and the process returns to step S12, the skin type is updated to step 3 in step S12, and the output voltage (Vout1) of the first D / A converter 45 is changed to the skin type 3 in step S13. The light emitting element 6a is turned on by setting the voltage (Vout1 = 1115.7 mV) to the voltage (Vout1 = 16.0 mV).

  Then, when a light receiving current (Ipd) is generated in the light receiving element 9a, and the generated light receiving current (Ipd) is given as a voltage signal to the input terminal (Vin) of the A / D converter 48 by the I / V conversion circuit 29, In step S14, the CPU 37 captures the light reception voltage value (AD0) from the A / D converter 48, determines whether the light reception voltage value (AD0) captured in step S15 is larger than the reference value, and in step S16, the light reception voltage. When the value (AD0) is larger than the reference value, the measurer determines that the skin type is 2, and returns to the main flow.

  If the received light voltage value (AD0) is smaller than the reference value in step S15, the skin type is further raised by one step in step S17, and the skin type raised in step S18 is the sixth skin type 6. It is determined whether or not there is a skin type 6 in the sixth stage, the process returns to step S12, and the operations in steps S12 to S18 are repeated from skin type 4 to skin type 6. As a result, the measurer determines which of skin types 1 to 5.

Next, the operation flow of the pulse wave observation process for observing the pulse wave of the observer shown in step S2 of FIG. 16 will be described with reference to FIG.
When the operation of this pulse wave observation process starts, the CPU 37 first determines which of the skin types 1 to 5 is based on the skin type confirmation process (step S21).

  If the skin type is one of skin types 1 to 5 (for example, skin type 3), the contents of the table 2 registered in the RAM 39 are read, and the output voltage of the first D / A converter 45 is based on the contents of the table 2 (Vout1) and the output voltage (Vout2) of the second D / A converter 47 are set to voltage values corresponding to any of skin types 1 to 5 (for example, skin type 3) (for example, V1 = 108 mV, V2 of skin type 3). = 1.91 mV) (step S22).

  Thereafter, the output voltage (Vout2 = 1.91 mV) of the second D / A converter 47 updated to a voltage value corresponding to any one of the skin types 1 to 5 (for example, skin type 3) is input to the A / D converter 48. The voltage (Vref2) is applied to adjust the light receiving sensitivity of the light receiving element 9a (step S23). Thereafter, the light emitting element 6a is turned on with the output voltage (Vout1 = 108 mV) of the first D / A converter 45 updated to a voltage value corresponding to any one of the skin types 1 to 5 (for example, skin type 3) (step S24). ).

  Then, the amount of the observation light emitted from the light emitting element 6a is controlled according to the skin type (for example, skin type 3) of the measurer, and the light from the light receiving circuit constituted by the A / D converter 48 from the light receiving element 9a. Of the observation light scattered within the skin H with the light receiving sensitivity controlled, the observation light transmitted through the epidermis H2 again and received by the light receiving element 9a was scattered within the depth range of the skin H at the dermis H1. Limited to observation light.

  At this time, the light-receiving element 9a is reached under conditions that are not affected by noise due to fluctuations in the optical characteristics of biological tissue below the subcutaneous tissue (fluctuations in optical characteristics accompanying body movement). As a result, the light receiving element 9a receives the observation light, which is the main cause of the fluctuation due to the quantitative fluctuation of the hemoglobin HE that is a light-absorbing substance in the dermis H1. The light receiving element 9a generates a light receiving current (Ipd) according to the amount of light received, and the generated light receiving current (Ipd) is converted into a voltage signal by the I / V conversion circuit 29 to the input terminal (Vin) of the A / D converter 48. ).

  The voltage signal input to the input terminal (Vin) is converted into a corresponding digital light reception voltage value (AD1) by the A / D converter 48 (step S25). The CPU 37 determines whether or not the converted light reception voltage value (AD1) is within a reference range from a minimum value to a maximum value of a predetermined voltage value (reference range from AD1min to AD1max) ( Step S26).

  At this time, if the light reception voltage value (AD1) is not within the reference range of the predetermined voltage value, a measurement error occurs and error processing is performed (step S27). If the light reception voltage value (AD1) is within a predetermined reference range of voltage values, the light reception voltage value (AD1 value), which is time-series data of A / D conversion data, is stored in the RAM 39 as pulse wave data. (Step S28). Based on the stored pulse wave data, a detection process for detecting biological information such as the pulse rate is performed (step S29).

  Thereafter, it is determined whether or not to end the pulse wave observation (step S30). When an end signal is given by operating the switch unit 34, the pulse wave observation process is ended and the process returns to the main flow. At this time, if the end signal of the pulse wave observation process is not given, the process returns to step S22, the operations from step S22 to step S30 are repeated again, and the pulse wave measurement is performed again.

  By the way, if it is determined in step S21 that the skin type is not the skin type 1 to 5 and the skin type is the sixth stage skin type 6 based on the skin type confirmation process, the table registered in the RAM 39. 2 is read, the output voltage (Vout1) of the first D / A converter 45 is updated based on this table 2 (step S31), and the output voltage (Vout2) of the second D / A converter 47 is the voltage corresponding to the skin type 6 A value (Vref2 = 0.28 mV) is set (step S32).

  Then, the output voltage (Vout2) of the second D / A converter 47 set to the voltage value corresponding to the skin type 6 is supplied to the A / D converter 48 as the input voltage (Vref2), and the light receiving sensitivity of the light receiving element 9a is adjusted. (Step S33). Thereafter, returning to step S24, the light emitting element 6a is caused to emit light again, and in step S25, the light receiving voltage (Vin) received by the light receiving element 9a is converted into a digital light receiving voltage value (AD1).

  In step S26, it is determined whether or not the light reception voltage value (AD1) is within a reference range from a predetermined minimum voltage value to a maximum voltage value. To store pulse wave data, which is time-series data of A / D conversion data for skin type 6, in the RAM 39 as waveform data, and to detect biological information such as the pulse rate based on the pulse wave data stored in step S29. When the pulse wave observation is completed in step S30, the process returns to the main flow.

  As described above, according to this biological information detection method, in order to optically observe the skin tissue of the human body by the light emitting element 6a, the observation light in the specific wavelength band is caused to emit light with the light emission amount determined in advance. Since the observation light that has been irradiated and scattered in the skin H is received by the light receiving element 9a whose light receiving sensitivity can be controlled, and the density of the melanin pigment contained in the skin H is measured, It is possible to know the density of the melanin element contained in the skin H.

  And based on this measurement result, since the light emission amount of the light emitting element 6a and the light receiving sensitivity of the light receiving element 9a are controlled, the pulse wave is accurately determined according to the density of the melanin pigment contained in the skin H of the measurer. Therefore, it is possible to accurately measure a biological signal such as a pulse wave without causing individual differences depending on the color depth of the skin. For this reason, it corresponds to this measured biological signal. Based on the pulse wave data to be detected, biological information such as a pulse can be detected accurately and reliably.

  In this case, the measurement light is emitted by the light emitting element 6a with a predetermined number of light emission amounts and irradiated to the skin H, and the observation light scattered in the skin H is received by the light receiving element 9a. The density of the melanin pigment contained in the person's skin H can be known. Thereby, according to the density of the melanin pigment contained in the skin H, it is possible to determine which of the six levels of the measurer's skin type. Further, based on the determination result of the skin type of the measurer, the light emission amount of the light emitting element 6a and the light receiving sensitivity of the light receiving element 9a are set according to the skin type of the measurer. Pulse waves can be observed accurately.

  That is, in the light emitting element 6a, the light emission amount is controlled according to the skin type of the measurer, and the light receiving sensitivity of the light receiving circuit including the A / D converter 48 is controlled from the light receiving element 9a. Even when a large amount of melanin pigment is contained in H2, the observation light scattered in the skin H and reaching the light receiving element 9a can be limited to the observation light scattered within the depth range of the dermis H1. .

  For this reason, as shown in FIG. 14, the observation light scattered in the skin H and incident on the light receiving element 9a suppresses the amount of the observation light that reaches the subcutaneous tissue below the dermis H1 included therein. be able to. At this time, the quantitative change of hemoglobin HE, which is a light-absorbing substance in the dermis H1, is received without being affected by the noise due to the fluctuation of the optical characteristics of the living tissue below the subcutaneous tissue (the fluctuation of the optical characteristics accompanying the body movement). can do. For this reason, it is possible to accurately observe the pulse wave without causing individual differences due to the darkness of the skin color.

  In addition, according to the biological information detection device 5, the observation light irradiating means (photoelectric signal) for irradiating the skin H by emitting the observation light in the specific wavelength band by the light emitting element 6a in order to optically observe the skin tissue of the human body. A detecting unit 26, a light emitting unit driving circuit 27), and a scattered light detecting unit (a light receiving unit 9a that receives the observation light irradiated by the observation light irradiating unit and scattered in the skin H, converts it into an electric signal, and outputs the electric signal). The photoelectric signal detection unit 26, the I / V conversion circuit 29, the reference voltage generation circuit 30, and the light emitting element 6a emit light with a predetermined light emission amount, and the light reception element 9a receives the received light amount. Control means for measuring the density of the melanin pigment contained in the skin H and controlling the light emission amount of the light emitting element 6a and the light receiving sensitivity of the light receiving element 9a based on the measurement result (control device 25, CPU 37, Light control circuit 28 and light reception control circuit 31), as described above, it is possible to accurately measure a biological signal such as a pulse wave without causing individual differences depending on the color of the skin. For this reason, it is possible to accurately and reliably detect biological information such as a pulse based on the pulse wave data corresponding to the measured biological signal.

  In this case, the control means causes the light-emitting element 6a to emit light a predetermined number of times with different light emission amounts for each of the skin types 1 to 6 and irradiate the skin H, and the irradiated observation light scattered in the skin H. Measuring means (a control device 25, a CPU 37, a light emission control circuit 28, a light reception control circuit 31) that respectively receives light by the light receiving element 9a and measures the density of the melanin pigment contained in the skin H according to the amount of light received. Therefore, the density of the melanin pigment contained in the skin H of the measurer can be measured.

  In addition, this control means includes determination means (control device 25, CPU 37, light emission control circuit 28, light reception control circuit 31) for determining which of the six types of skin H is in accordance with the measurement result by the measurement means. Since it is provided, according to the density of the melanin pigment contained in the skin of the measurer, it is possible to determine which of the six levels of the measurer's skin type.

  Furthermore, this control means sets the light emission amount of the light emitting element 6a and the light receiving sensitivity of the light receiving element 9a to any one of six types of skin types based on the determination result of the determination means, and is an observation means for observing pulse waves ( Since the control device 25, the CPU 37, the light emission control circuit 28, and the light reception control circuit 31) are provided, the light emission amount by the light emitting element 6a can be accurately set according to the skin type of the measurer and the skin of the measurer. Observation light can be received with the light receiving sensitivity of the light receiving element 9a according to the type, and the pulse wave can be observed very accurately.

  By the way, in this living body information detection apparatus 5, when the observation light of the specific wavelength band is emitted by the light emitting element 6a, the observation light can be diffused and irradiated on the skin H by the light guide member 7, so that the observation light can be irradiated. Light can be uniformly applied to a wide area of the skin H, and the observation light scattered in the skin H by the light receiving element 9a arranged corresponding to the center of the irradiated annular irradiation area E can be obtained. Since the light can be received, the observation light can be received efficiently and stably by the light receiving element 9a.

  For this reason, the observation light from the light emitting element 6a can be uniformly irradiated over a wide area of the skin H, the irradiation optical path for irradiating the skin H with the observation light from the light emitting element 6a, and the observation scattered by the skin H. Since the light receiving optical path for receiving the light can be completely separated, the observation light diffused and irradiated on the skin H can be received efficiently and stably by the light receiving element 9a, whereby a living body such as a pulse wave can be received. The signal can be measured accurately.

  In this way, the observation light incident on the dermis H1 is uniformly irradiated over a wide ring-shaped area as compared with the case where a part of the observation light is irradiated in a spot manner. The amount of hemoglobin, which is a light-absorbing substance, can be increased, thereby improving the detection sensitivity of the quantitative variation of hemoglobin in the living tissue in the dermis H1.

  In addition, an optical filter 20 that transmits light in a specific wavelength band is provided on the lower surface that is the incident surface of the light receiving unit 9, so that unnecessary light such as extraneous light is transmitted to the light receiving unit 9 by the optical filter 20. Irradiation can be reduced. As a result, only the observation light emitted from the light emitting unit 6 and scattered in the skin H can be reliably received by the light receiving unit 9, so that the living tissue can be accurately measured, and the human body The measurement accuracy of the pulse wave can be increased.

  In this case, the light receiving unit 9 has a spectral sensitivity characteristic that reacts to light having a specific wavelength band of about 900 nm that is transmitted by the optical filter 20, so that only the light having the specific wavelength band that has passed through the optical filter 20 is accurately detected. Light can be received and photoelectrically converted. At this time, unnecessary light contained in extraneous light such as sunlight is blocked by the optical filter 20, and fluctuations of the light receiving unit 9 due to extraneous light can be reduced. Can be measured, and the measurement accuracy of the pulse wave of the human body can be improved.

  Further, since this wristwatch has a configuration in which the biological information detecting device 5 is provided on the back cover 3 in the wristwatch case 1, the wristwatch case 1 can be attached to an arm and used. That is, when the wristwatch case 1 is attached to the arm, the back cover 3 comes into contact with the skin H of the arm. Therefore, a part of the biological information detecting device 5 exposed from the attachment hole 3b of the back cover 3 in contact with the skin H comes into contact. Can be made. For this reason, it is possible to easily and easily measure a biological signal anytime and anywhere with the wristwatch case 1 attached to the arm.

  In the above-described embodiment, the observation light is emitted with a predetermined light emission amount by the light emitting element 6a and irradiated to the skin H, and the observation light scattered in the skin H is received by the light receiving element 9a, and the measurement person's The case where the density of the melanin pigment contained in the skin H is measured, and the skin tissue is observed by controlling the light emission amount of the light emitting element 6a and the light receiving sensitivity of the light receiving element 9a based on the measurement result is described. However, the present invention is not limited thereto, and the skin tissue may be observed by controlling only one of the light emission amount of the light emitting element 6a and the light receiving sensitivity of the light receiving element 9a based on the measurement result.

  In the embodiment described above, the density of the melanin pigment contained in the skin H is measured. In addition to the density of the melanin pigment contained in the skin H, the concentration or amount of the melanin pigment, etc. Other biological characteristics representing the state of the living body may be measured. In addition to measuring the density of melanin pigment contained in skin H, other biological conditions such as hemoglobin concentration in blood, oxygen saturation of hemoglobin, and glucose concentration in skin tissue are also measured. Anyway.

  Furthermore, in the above-described embodiment, the case where the present invention is applied to a wristwatch has been described. However, the wristwatch does not necessarily have to be a wristwatch, and may be an arm-mounted type that is used by wearing on an arm, and is not necessarily attached to an arm. The present invention can be widely applied not only to what is used, but also to what is used by being worn on a human body such as a finger or a foot.

DESCRIPTION OF SYMBOLS 1 Watch case 3 Back cover 4 Watch module 5 Biological information detection apparatus 6 Light emission part 6a Light emission element 7 Light guide member 8 Observation light taking part 9 Light reception part 9a Light reception element 10 Circuit board 25 Control apparatus 26 Photoelectric signal detection part 27 Light emission part Drive circuit 28 Light emission control circuit 29 I / V conversion circuit 30 Reference voltage generation circuit 31 Light reception control circuit 37 CPU
38 ROM
39 RAM
45 1st D / A converter 46 Constant current circuit 47 2nd D / A converter 48 A / D converter If Light emission current Ipd Light reception current Vin Light reception voltage AD0, AD1 Light reception voltage value H Skin H1 Dermal H2 Epidermis ME Melanin pigment HE Hemoglobin

Claims (8)

In order to optically observe the skin tissue of the human body with a light emitting element, the observation light in a specific wavelength band is emitted with a predetermined amount of light to irradiate the skin, and this irradiation is scattered within the skin. A first step of measuring the density of the melanin pigment contained in the skin by receiving the observed light with a light receiving element whose light receiving sensitivity is controllable;
A second step of controlling at least one of the light emission amount of the light emitting element and the light receiving sensitivity of the light receiving element based on the measurement result measured in the first step;
A biological information detection step of detecting biological information corresponding to the density of the melanin pigment based on the control result controlled by the second step;
A biological information detection method comprising: In order to optically observe a living body with a light emitting element, the observation light in a specific wavelength band is emitted with a predetermined amount of light to irradiate the living body, and the irradiation is irradiated and scattered in the living body. Receiving a scattered light of light with a light receiving element whose light receiving sensitivity is controllable, and measuring a state of the living body;
A second step of controlling at least one of the light emission amount of the light emitting element and the light receiving sensitivity of the light receiving element based on the measurement result measured in the first step;
A biological information detection step for detecting biological information indicating the state of the living body based on the control result controlled in the second step;
A biological information detection method comprising:   The first step includes an irradiation step of irradiating the skin by irradiating the observation light with a predetermined number of light emission amounts by the light emitting element and irradiating the skin, and each irradiation step irradiates and scatters in the skin. A light receiving step for receiving the observation light by the light receiving element, and a density measuring step for measuring the density of the melanin pigment contained in the skin based on the scattered light received by the light receiving step. The biological information detection method according to claim 1, wherein:   In the second step, based on the measurement result in the first step, the light emission amount of the light emitting element and the light receiving sensitivity of the light receiving element correspond to any of the plurality of skin types, respectively. The biological information detection method according to claim 1, further comprising an observation step of setting and observing the skin tissue. Observation light irradiating means for irradiating the skin by emitting observation light of a specific wavelength band by a light emitting element in order to optically observe human skin tissue;
The scattered light detecting means for receiving the observation light irradiated by the observation light irradiation means and scattered in the skin by a light receiving element, converting it into an electrical signal, and outputting the electric signal;
The light emitting element is caused to emit light with a predetermined light emission amount, and the emitted observation light is received by the light receiving element, and the density of the melanin pigment contained in the skin is measured according to the light reception amount, And a control means for controlling at least one of the light emission amount of the light emitting element and the light receiving sensitivity of the light receiving element based on the measurement result;
Based on the control result controlled by the control means, biological information detection means for detecting biological information corresponding to the density of the melanin pigment,
A biological information detection device comprising: In order to optically observe a living body with a light emitting element, the observation light in a specific wavelength band is emitted with a predetermined amount of light to irradiate the living body, and the irradiation is irradiated and scattered in the living body. Measuring means for measuring the state of the living body by receiving scattered light of light with a light receiving element whose light receiving sensitivity is controllable,
Control means for controlling at least one of the light emission amount of the light emitting element and the light receiving sensitivity of the light receiving element based on the measurement result measured by the measuring means;
Biological information detection means for detecting biological information indicating the state of the living body based on the control result controlled by the control means;
A biological information detection method comprising: The measuring means causes the light emitting element to emit light a predetermined number of times with different amounts of light to irradiate the skin, and receives the observation light that has been irradiated and scattered within the skin by the light receiving element, respectively. A density measuring means for measuring the density of the melanin pigment contained in the skin according to the received light amount,
The control means determines whether the skin type is in a plurality of stages according to the measurement result by the measurement means, and the light emission amount of the light emitting element based on the determination result by the determination means 6. An observation means for observing the skin tissue by setting at least one of the light receiving sensitivity of the light receiving element so as to correspond to any one of the plurality of stages of skin types. The biological information detection apparatus according to 1. A human body-mounted device, wherein the biological information detecting device according to claim 5 or 6 is provided in a device body that is mounted on a human body.

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