JP5374835B2 - Biological information measuring apparatus and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biological information measuring apparatus capable of suppressing the saturation of the output of a light receiving element, then, accurately measuring biological information such as pulses, and a control method therefor. <P>SOLUTION: The biological information measuring apparatus is equipped with: a light emitting element 21 for emitting light at a prescribed light emitting frequency to the detection region of an organism; the light receiving element 22 capable of receiving the emitted light through the organism and receiving external light in linkage with the body motion of the organism and generating light receiving signals on the basis of a light receiving quantity changed according to the pulsation and body motion of the organism; a liquid crystal filter 31 disposed on the light receiving part side of the light receiving element 22 and capable of freely varying the transmission quantity of the light to the light receiving part; a light transmission quantity control part for controlling the light transmission quantity of the liquid crystal filter 31 and suppressing the light receiving quantity of the light receiving element 22 to a saturation level or below; and a biological information specifying part for specifying body motion components and pulsation components on the basis of the signal components of a first frequency range including the light emitting frequency and the signal components of a second frequency range lower than the first frequency range in the light receiving signals. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to an optical biological information measuring device and a control method thereof.

  2. Description of the Related Art Conventionally, there is a pulse measuring device by optical sensing that irradiates light from a light emitting element toward a detection part of a living body and receives the light to obtain pulse information. Various techniques for removing the influence of external light such as sunlight and illumination light have been proposed for this type of optical pulse measuring device. For example, a low-pass after a light emitting element is driven on a light receiving side and amplified on the light receiving side. A technique for reproducing a pulse waveform with a filter (for example, see Patent Document 1), a technique for extracting a pulse waveform with a band-pass filter that passes through a pulse frequency band after light reception (for example, see Patent Documents 2 and 3), and light reception There is a technique for demodulating only the light modulation component to remove the influence of external light (for example, see Patent Document 4).

Further, in this type of optical pulse measuring device, in order to detect noise (external light or the like) in a measurement signal, for example, two light emitting elements having different wavelengths, a first wavelength light, a second wavelength light, A plurality of integration means for integrating each received light signal when non-light emission is repeated, a technique for determining whether or not the noise level at the time of non-light emission is within an allowable range (for example, see Patent Document 5), and A filter (0.5 Hz to 2.3 Hz) for passing a pulse signal and a noise component passing filter for passing a signal component having a frequency lower than that of the pulse are provided, and the pulse wave signal is detected during noise generation period detection and noise generation detection. There is a technique (for example, refer to Patent Document 6) that cuts off the output of a filter that passes the filter. Further, this type of pulse measuring device has been proposed that detects a pulse and body movement using a plurality of sensors (for example, Patent Documents 7, 8, and 9).
Japanese Utility Model Publication No. 53-76697 Japanese Patent Laid-Open No. 2001-145606 JP 2004-202190 A Japanese Patent No. 2,693,958 Japanese Patent No. 3291581 JP-A-1-288230 JP-A-7-88092 JP 2005-28157 A Japanese Patent Laid-Open No. 11-276448

  However, in the conventional configuration, when strong external light is incident, the output of the light receiving element is saturated, and there is a possibility that accurate pulse measurement cannot be performed during that time. In addition, when external light is intermittently received and there is a noise component close to the frequency of the pulse waveform, the noise component cannot be removed, or a plurality of light emitting elements, a plurality of light receiving elements, or a dedicated body motion sensor is provided. Therefore, there is a problem that the number of components increases.

  The present invention has been made in view of the above-described circumstances, and provides a biological information measuring apparatus and a control method thereof that can accurately measure biological information such as a pulse by suppressing saturation of the output of a light receiving element. is there.

To solve the above problems, the present invention provides a biological information measuring device, generates a light emitting element for irradiating light toward the detection site of a living body, a light receiving signal by receiving the light through the living body light an element, the amount of light transmission variable filter to increase or decrease the transmission amount of light incident on the light receiving element, and the light transmission amount control unit for controlling the amount of light transmission of the light transmission variable filter, based on the light receiving signal , characterized in that it comprises a biological information identification unit for identifying the pulsating component.

According to the present invention, it is possible to suppress the saturation of the light receiving element. Therefore, based on the light reception signal, with the biological information specifying unit for specifying a pulsating component, can be performed measuring accurate pulse rate monitor to suppress saturation of the output of the light receiving element.
In the above configuration, it is preferable that the light transmission amount control unit lowers the light transmission amount of the light transmission amount variable filter from the maximum transmission state until the light reception amount of the light receiving element becomes equal to or lower than a saturation level. According to this configuration, saturation of the light receiving element can be suppressed.
The biological information specifying unit may include a first signal component in a first frequency range that includes the frequency of the light and a second signal component in a second frequency range that is lower than the first frequency range. Based on this, the pulsation component may be specified. According to this configuration, the frequency spectrum corresponding to the pulsation component and the body motion component appearing in the blood flow fluctuation can be specified from the first signal component corresponding to the light of the light emitting element that has passed through the living body, and the first corresponding to the external light. The frequency spectrum corresponding to the body motion component can be specified from the two signal components, and the pulse wave spectrum and the body motion spectrum can be detected with high accuracy.

In the above configuration, the biological information identification unit performs a process of identifying a plurality of frequency spectra by performing frequency analysis on the first signal component, and identifying a body motion spectrum by performing frequency analysis on the second signal component. a frequency analysis section for executing, when the frequency analysis unit has identified the body motion spectrum, among the frequency spectrum contained in the first signal component, a frequency spectrum excluding the body motion spectrum and pulse wave spectrum specific and preferably has a pulse rate specifying section for specifying the pulse rate from the pulse wave spectrum. According to this configuration, the frequency spectrum corresponding to the pulsation component and the body motion component appearing in the blood flow fluctuation can be specified from the first signal component corresponding to the light of the light emitting element that has passed through the living body, and the first corresponding to the external light. The frequency spectrum corresponding to the body motion component can be specified from the two signal components, and the pulse wave spectrum and the body motion spectrum can be detected with high accuracy.

In the above configuration, the light transmission amount control unit obtains a light reception average level from the frequency analysis result of the first signal component by the frequency analysis unit, and uses a predetermined level in the frequency analysis result based on the light reception average level. It is preferable to determine whether or not a peak exists, and to reduce the light transmission amount of the light transmission variable filter from the maximum transmission state until the peak exists. According to this configuration, the saturation of the light receiving element can be determined only by the frequency analysis result based on the frequency analysis result.
Moreover, the said structure WHEREIN: The said biological information specific | specification part has a low-pass filter which passes the body movement frequency range of the said biological body among the said light reception signals, and extracts the 2nd signal component of the said 2nd frequency range. Is preferred. According to this configuration, it is possible to accurately extract the body motion component that appears in the change in the amount of received external light.
In the above configuration, the light transmission amount control unit lowers the light transmission amount of the second region different from the first region in which the light of the light emitting element is incident, from the maximum transmission state of the light transmission amount variable filter. It is preferable. According to this configuration, the amount of light transmitted through the light emitting element can be reduced almost without reducing the amount of light transmitted outside, and light including pulsation information can be received at an appropriate level for accurate pulse measurement and body motion measurement. Can continue.

In the above structure, the light transmission control unit, the second region of the light transmission variable filter relative, Yasu is preferably increased halftone region or the non-transmissive region. According to this arrangement, the amount of received light can lower the gel by Yasu increasing halftone region or the non-transmissive region.
In the above configuration, it is preferable that the first region is a central region in plan view of the light transmission amount variable filter. According to this configuration, even if the positional relationship between the light emitting element and the detection site is slightly deviated, the light from the light emitting element can be reliably incident.

Further, the configuration smell Te, before Symbol light transmission variable filter is preferably a transmissive liquid crystal panel.

Further, in the above configuration, the biological information specifying unit passes through a frequency range in which the frequency of the light of the received light signal is approximately a center frequency, and extracts a first signal component in the first frequency range. It is preferable to have a filter. According to this configuration, the first signal component corresponding to the light of the light emitting element that has passed through the living body can be extracted with high accuracy.

Further, in the above configuration, when the biological information specifying unit cannot specify a body movement component, the light receiving element includes a pseudo external light irradiation unit that emits pseudo external light that can be received in conjunction with the body movement of the living body. It is preferable. According to this configuration, even in a situation where external light cannot be received, a body motion component appearing in a change in the amount of pseudo external light received can be extracted, and a pulse or the like can be detected with high accuracy.
In the above structure, the light-emitting element preferably emits infrared light having a single peak wavelength or red light having a single peak wavelength. According to this configuration, it is possible to irradiate light that is difficult to be absorbed in the body.

Further, the present invention is a control method for the biological information measurement device, and irradiates light toward the detection site of a living body to produce a light receiving signal by receiving the light through the living body by the light receiving element, wherein controls the optical transmission of the light transmission quantity variable filter light incident on the light receiving element is transmitted, on the basis of the received light signal, and identifies the pulsating component.

According to the present invention, it is possible to suppress the saturation of the output of the light receiving element performs measurements accurate pulse rate monitor.

  In addition to being applied to the above-described biological information measuring apparatus and its control method, the present invention distributes a control program for carrying out the present invention to general users via an electric communication line, or installs such a program. It can also be implemented in such a manner that it is stored in a computer-readable recording medium such as a magnetic recording medium, an optical recording medium, or a semiconductor recording medium and distributed to general users.

According to the present invention, it is possible to accurately measure the biological information of the pulse such as to suppress the saturation of the output of the light receiving element.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<First Embodiment>
FIG. 1 is a diagram showing a pulse measuring device according to the first embodiment of the present invention. The pulse measuring device 1 is configured as a wristwatch, and includes a device main body 2 and a wristband (band-like body) 3 that extends from the device main body 2 at the 6 o'clock position and the 12 o'clock position and is wound around the user's arm. It is configured so that the user can easily wear it when performing exercises such as jogging and running.

  The apparatus main body 2 includes a display unit 5 that displays various information such as a pulse rate and time, and a plurality of operation switches 6A, 6B, and 6C that function as an operation unit for a user to perform various instructions. The operation switch 6A is an operator for starting / stopping pulse measurement. For example, each time the operation switch 6A is operated, the operation mode is switched between a pulse measurement mode and a time display mode. The operation switch 6B is an operation element for instructing start of various setups such as time setting and an instruction for changing the operation mode. The operation switch 6C is an operation element for clearing the setup and turning on a light (not shown). In the illustrated example, the operation switches 6A to 6C are push-type switches, but may be electrostatic switches or touch switches using membrane electrodes.

  FIG. 2 shows the internal structure of the apparatus main body 2 (cross section at 3 o'clock to 9 o'clock). The apparatus main body 2 includes an exterior case 7 and a back cover 8, and the exterior case 7 is formed of a material that does not transmit light (light non-transparent material) such as a metal material or a non-transparent resin material. A display cover glass 10 is fixed to the exterior case 7 on the timepiece front side, and a middle frame 11 is inserted from the back side (downward in FIG. 2). The middle frame 11 has a timepiece front side (FIG. 2). The liquid crystal panel 12 and the circuit board 13 that constitute the display unit 5 and the battery 14 are disposed in order from the middle (upward), and the back side opening of the outer case 7 is sealed with the back cover 8. 2 is a conductive block (zebra connector) for electrically connecting the liquid crystal panel 12 and the circuit board 13, and numerals 16 and 17 are batteries for supplying battery power to the circuit board 13. It is a contact point.

The back cover (back cover for light guide member) 8 is fixed to the outer case 7 with a screw structure or the like, and is a transparent or colored transparent light-transmitting material (for example, a plastic material such as plastic). By being formed, it also serves as a light guide member that transmits light. A circuit board 19 is fixed to the back cover 8 with a screw 19 </ b> A on the battery 14 side, and the circuit board 19 is electrically connected to the circuit board 13 through a flexible wiring 18.
The circuit board 19 includes an optical sensor (hereinafter referred to as a biological information detection unit) 20 for detecting biological information, a single light emitting element 21, a light receiving element 22, and peripheral components for driving these elements 21, 22. And a liquid crystal filter (light transmission variable variable filter) 31 that suppresses light to a level at which the light receiving element 22 is not electrically saturated even by direct sunlight such as sunlight, and components that constitute a pseudo outside light irradiation unit 25 described later. Implemented.

The light emitting element 21 and the light receiving element 22 are mounted on the surface of the circuit board 19 on the back side, and peripheral components are mounted on the surface of the circuit board 19 on the timepiece side. The degree of freedom of arrangement of the light emitting element 21 and the light receiving element 22 can be increased while downsizing the substrate 19.
The light emitting element 21 is disposed at substantially the center of the circuit board 15 (near the center in the plane direction of the apparatus main body 2), and emits light L1 of 700 nm or more, specifically, visible light having a single peak wavelength. LED that emits infrared light that is not easily absorbed by the body or red light having a single peak wavelength is applied, and light is directed toward the user's wrist (blood flow site) X through the transparent back cover 8. Irradiate L1.

  The light receiving element 22 is arranged at approximately 3 o'clock side with respect to the light emitting element 21, and is a phototransistor (for example, capable of receiving light in the wavelength region of the light emitting element 21 and external light L3 such as sunlight or illumination light). A phototransistor having a light receiving wavelength region of 700 nm or more is used. The light receiving element 22 receives the reflected light L2 irradiated by the light emitting element 21 and reflected by the blood vessel or the like of the wrist X through the transparent back cover 8 and the liquid crystal filter 31, and receives light at a signal level corresponding to the amount of light received. The signal S1 is output.

Here, the light L1 emitted from the light emitting element 21 changes in absorbance according to the blood flow flowing through the blood vessel, so that the amount of the reflected light L2 changes according to the blood flow. In this case, the blood flow in the blood vessel changes not only due to pulsation but also due to body movement (movement of the body itself such as arm swing and movement of the skin surface that changes when bending a joint such as the wrist). The amount of light of the reflected light L2 changes according to pulsation and body movement. Therefore, the light receiving element 22 outputs a light receiving signal S1 having a signal level corresponding to pulsation and body movement.
In the present embodiment, a case where the reflection type is configured to receive reflected light will be described. However, the present invention is not limited to this, and in the case where a pulse is detected from a blood vessel such as a finger by the biological information detection unit 20, Or the like).

The reason why the light receiving wavelength region of the light receiving element 22 is set to 700 nm or more is that not only the reflected light L2 of the light L1 of the light emitting element 21 is surely received but also external light L3 such as sunlight or illumination light is received. Because.
Here, when the external light L3 is received by the light receiving element 22, the wristband 3 of the pulse measuring device 1 is usually wound around the user's wrist X with a certain amount of play. When the user wearing the pulse measuring device 1 swings his arm or the like, as shown in FIG. 2, there is a gap between the device main body 2 (back cover 8) and the wrist X, and the gap passes through the gap. This is a case where the external light L3 is reflected by the wrist X and received by the light receiving element 22.

That is, in the present embodiment, the external light L3 is generated between the apparatus main body 2 (the back cover 8) and the wrist X, in other words, when there is almost no gap between the biological information detection unit 20 and the wrist X. When the light receiving element 22 hardly receives light and there is a gap between the biological information detection unit 20 and the wrist X, the light reaching the light receiving element 22 changes according to the gap and receives the external light L3. Thus, it is configured to be able to receive external light L3 whose amount of light changes according to body movement.
Here, the reason why the light receiving element 22 is arranged on the 3 o'clock side of the pulse measuring device 1 is that when the pulse measuring device 1 is mounted on the user's left wrist, sunlight or illumination light (external light) is generated by the user's arm swing or the like. This is because L3) easily enters the gap on the back side of the apparatus body 2 from the 3 o'clock side. However, the light receiving element 22 is not limited to being arranged at the 3 o'clock side, and may be arranged at a position other than the 3 o'clock side.

Note that the infrared light component and the red light component of the external light L3 are particularly difficult to be absorbed by the living body, and therefore easily pass through the wrist X and the surface of the living body (skin etc.). For this reason, even when there is no large gap on the back side of the device body 2, depending on the posture of the device body 2 that changes according to the body movement of the user, the external light L3 may be received by the light receiving element 22, Also by this, the external light L3 can be received according to the body movement.
As described above, in this embodiment, since an element capable of receiving the external light L3 is used as the light receiving element 22, conventional optical elements using a light receiving element that does not include the external light L3 such as sunlight or illumination light in the light receiving wavelength band. A general-purpose light-receiving element can be widely applied as compared with the type pulse measuring device. The light receiving element 22 is not limited to a general-purpose phototransistor, and a widely distributed photoelectric sensor such as a general-purpose photodiode can be applied.

In the present embodiment, in an environment where there is almost no external light L3 such as sunlight or illumination light, the light receiving element 22 cannot receive the external light L3. A pseudo external light irradiation unit 25 that irradiates L5 (hereinafter referred to as pseudo external light) is provided.
More specifically, as shown in FIG. 2, the pseudo external light irradiation unit 25 has a single pseudo external light emitting element 26 that emits pseudo external light L5 that can be received by the light receiving element 22. The pseudo-external light emitting element 26 is mounted on the back surface of the circuit board 19 and emits light similar to the light emitting element 21 (light of 700 nm or more), more specifically, a single peak wavelength. An LED that emits infrared light that is less absorbed by the body than visible light or red light having a single peak wavelength is used.

  The pseudo external light emitting element 26 is disposed at a position approximately 9 o'clock with respect to the light emitting element 21 and the light receiving element 22, and pseudo external light is directed toward the user's wrist X through the transparent back cover 8. L5 is emitted. The emission direction of the pseudo external light L5 is directed to the light receiving element 22 side, and the incident angle with respect to the wrist X is set to be large. The pseudo external light L5 is reflected by the wrist X, and the wristband 3 and the wrist. The amount of light that reaches the light receiving element 22 changes in accordance with the gap with X. Thereby, the pseudo external light irradiation unit 25 emits the pseudo external light L5 in which the amount of received light changes in accordance with the body movement in the same manner as the external light L3.

Next, the liquid crystal filter 31 will be described. As the liquid crystal filter 31, not only simple black and white display but also a transmissive liquid crystal panel capable of gray display (halftone display) and various pattern displays is applied, and is arranged between the light receiving element 22 and the back cover 8. It functions as a light transmission variable filter that varies the amount of light transmitted to the light receiving element 22.
As shown in FIG. 2, the liquid crystal filter 31 is fixed to the circuit board 19 via a light shielding member 32 that extends from the periphery of the light receiving element 22 to the watch back side and can block direct light L1 and the like from the light emitting element 21. As shown in FIG. 3A, a predetermined gap (1.0 mm in this example) is provided between the light receiving portion 22A (2 × 2 mm in this example) of the light receiving element 22 and fixed, and one end thereof It is electrically connected to the circuit board 19 via the flexible wiring 33 connected to the side (3 o'clock side in this example), and is driven by a filter driving unit 40 described later formed on the circuit board 19.

Further, the liquid crystal display portion (6 × 6 mm in this example) of the liquid crystal filter 31 is configured to be large with respect to the light receiving portion 22A so that oblique light can be taken in efficiently. In the present embodiment, it is shown in FIG. According to the configuration, the light L2 from the light emitting element 21 is incident on the substantially central region (first region) of the liquid crystal filter 31, the external light L3 is incident on the 3 o'clock region of the liquid crystal filter 31, and the pseudo external light L5 is the liquid crystal filter. It is comprised so that it may inject into the 9 o'clock side area | region of 31. Here, the light L2 from the light emitting element 21 is incident on the substantially central region of the liquid crystal filter 31, so that the light L2 of the light emitting element 21 can be reliably obtained even when the positional relationship between the light emitting element 21 and the user's wrist X is slightly shifted. Can be incident.
The liquid crystal filter 31 uses a TFT (Thin Film Transistor) liquid crystal having 6 pixels in the vertical direction and 6 pixels in the horizontal direction. As schematically shown in FIG. 3B, the light incident side (in FIG. In order from the lower side, a polarizing plate 31A, a glass substrate 31B, a TFT layer 31C, an alignment film 31D, a liquid crystal layer 31E, an alignment film 31F, a common electrode (transparent electrode) 31G, a glass substrate 31H, and a polarizing plate 31I are stacked. Configured.

  4A is a plan view of the TFT layer 31C, FIG. 4B is a perspective view showing the TFT layer 31C together with peripheral components, and FIG. 4C shows a partially enlarged view of the TFT layer 31C. ing. FIG. 5 shows the electrode configuration of the TFT layer 31C. As shown in these drawings, the TFT type liquid crystal filter 31 includes a gate electrode (six gate electrodes (scanning lines) G1 to G5 in this example) 35 and data electrodes (six data electrodes (in this example)) in the vertical and horizontal directions. The data lines D1 to D6) 36 are arranged so as to intersect with each other, and pixel circuits (switching elements 37 and pixel electrodes 38) are formed at positions corresponding to the intersections of the electrodes 35 and 36, respectively.

With the above configuration, when the liquid crystal filter 31 is selected by setting the gate electrode 35 to the H level, the voltage of the data electrode 36 is applied to the liquid crystal cell of the column selected by the gate voltage, and is provided at the intersection of the electrodes 35 and 36. Display is performed by changing the transmittance of the corresponding pixel region of the liquid crystal layer 31E according to the potential difference between the pixel electrode 38 and the common electrode 31G. In this liquid crystal drive, the liquid crystal is driven so as to be AC driven with respect to the voltage of the common electrode 31G in order to suppress deterioration of the liquid crystal display.
More specifically, as shown in FIG. 6 as an example of the liquid crystal driving waveform, one frame constituting one screen is divided into a positive field and a negative field, and the gate electrode 35 is sequentially set to the H level in each field. (Gate electrode G1, gate electrode G2,...) And data electrode 36 (data electrode D1, data electrode D2,...) According to the gradation (transmittance) (positive potential in the positive field, negative potential in the negative field). Potential) is applied, and display signals are written to all the pixels within each field time. As a result, plus and minus signals are written to each pixel in one frame, and the AC drive of the liquid crystal filter 31 is performed.

  The liquid crystal filter 31 is desirably configured by a VA mode (vertical alignment) of a TFT driving method, which is generally said to have a high contrast, but is not limited thereto. For example, the liquid crystal mode is STN (Super Twisted Nematic), GH (Guest Host), PC (Phase Change Liquid Crystal), PDLC (Polymer Discharged Liquid Crystal), FLC (Ferroelectric Liquid Crystal, etc.). is there.

  FIG. 7 is a block diagram of the pulse measuring device 1, and FIG. 8 is a diagram showing its circuit configuration. In FIG. 7, the light emission control unit 50 performs light emission control of the light emitting element 21. The light emission control unit 50 divides an oscillation signal (for example, 32 kHz) of an oscillation circuit (not shown) by 2 kHz (1/16 division). When a signal is input, the driving power is supplied to the light emitting element 21 when the 2 kHz signal is at the H level, and the driving power supply is stopped when the 2 kHz signal is at the L level, and thereby a time corresponding to a 2 kHz duty ratio of 50%. Repeat lighting / extinguishing at intervals. That is, in this pulse measuring device 1, 2 kHz is set as the light emission frequency (also referred to as intermittent drive frequency) that defines the time interval of light emission.

  The current-voltage converter 51 performs current / voltage conversion on the received light signal S1 output from the light receiving element 22, and as shown in FIG. 8, connects the output of the operational amplifier 51A and the input − through a resistor 51B. A capacitor 51C is connected in parallel, a current proportional to the amount of received light is converted into a voltage, amplified by an operational amplifier 51A, and output. The light reception signal S2 converted by the current-voltage conversion unit 51 is output to a band-pass filter unit (first filter) 52 and a low-pass filter unit (second filter) 53, respectively.

  The band pass filter unit 52 extracts a signal component (first signal component) in a first frequency range including the light emission frequency (2 kHz) from the light reception signal S2 output from the current-voltage conversion unit 51. More specifically, the band-pass filter unit 52 uses the emission frequency as the center frequency (f0) and has a higher frequency range than the low frequency range that passes through the low-pass filter unit 53 (1 kHz or more in this configuration). The signal component of is passed. As a result, the signal component of the light passing through the living body (the reflected light L2 of the light L1) can be extracted. In other words, the signal component whose amplitude level varies according to the blood flow variation (variation due to pulsation and body movement). Can be taken out.

As shown in FIG. 8, the band-pass filter unit 52 connects the output of the operational amplifier 52A and the input − through the resistor 52B and the capacitors 52C and 52D, and is connected to the input to the input −. It is composed of a multiple feedback active filter circuit to which resistors 52E and 52F are connected. For this reason, compared with the case where it comprises with a passive filter circuit, there exists an advantage that the freedom degree of the frequency characteristic obtained is high and can be amplified.
Here, the reason why the pass frequency of the band pass filter unit 52 is set to 1 kHz or more is to remove a frequency signal (corresponding to a noise component) of 1 kHz or less that is generally used in an infrared home appliance remote controller.

The low-pass filter unit 53 extracts a signal component in the second frequency range lower than the pulsation frequency from the light reception signal S2 output from the current-voltage conversion unit 51. In other words, the low-pass filter unit 53 receives light according to body movement. The filter is configured to extract a body motion component due to external light L3 incident on the element 22.
Here, the body motion component (the body motion such as arm swing during walking or running or the movement of the skin surface that changes when the wrist joint is bent) is usually greater than 0 Hz and less than or equal to 10 Hz. Therefore, the low-pass filter unit 53 is configured as a filter having a cutoff frequency (fc) of 10 Hz, for example. As shown in FIG. 8, the low-pass filter unit 53 includes an active filter circuit in which resistors 53A and 53B, capacitors 53C and 53D, and an operational amplifier 53E are combined. The obtained frequency characteristics have a high degree of freedom and can be amplified.

  As shown in FIG. 7, an amplification unit (first amplification unit) 55 whose amplification factor can be changed by an amplification factor change unit 54 and a detection unit (first detection unit) are provided at the subsequent stage (output side) of the bandpass filter unit 52. 56) are connected in order, and an amplification unit (second amplification unit) 58 whose amplification factor can be changed by the amplification factor changing unit 57 is connected to the subsequent stage (output side) of the low-pass filter unit 53.

  The amplifying unit 55 and the amplification factor changing unit 54 are for amplifying the received light signal S3 having passed through the band-pass filter unit 52 to a signal level suitable for arithmetic processing (frequency analysis processing) by the arithmetic processing unit 60. . As shown in FIG. 8, the amplifying unit 55 and the amplification factor changing unit 54 switch the resistors 54A, 55C, and 54C in a feedback path that connects the output and the input − of the operational amplifier 55C in which the resistors 55A and 55B are arranged at the front and rear. The circuit is configured to be connectable via the elements 54D, 54E, and 54F, and the amplification factor is changed by controlling the on / off of each of the switching elements 54D to 54F under the control of the arithmetic processing unit 60.

  The detector 56 detects the envelope of the light reception signal S3 amplified by the amplifier 55. As shown in FIG. 8, the input signal is passed through a Schottky diode 56A, and a parallel circuit of a resistor 56B and a capacitor 56C. The circuit received in is applied. By appropriately designing the time constants of the resistor 56B and the capacitor 56C, the output waveform can be made close to the envelope of the input waveform.

  Instead of the detection unit 56, a detection unit may be provided for peak-holding the local maximum values or the local minimum values of the light reception signal S3 and connecting them to detect the envelope. In this case, the detection unit includes a digital memory scope that acquires waveform data obtained by analog-to-digital conversion of the received light signal S3, and peaks and holds the local maximum values or the local minimum values of the waveform data acquired in the digital memory scope. What is necessary is just to acquire the obtained envelope. In this way, by obtaining an envelope connecting the maximum values or the minimum values, the influence of the noise component can be reduced and the envelope can be detected. In this case, the envelope does not include the waveform of the pulsation itself, but includes a waveform of ½ frequency of the pulsation.

  The amplifying unit 58 and the amplification factor changing unit 57 are for amplifying the received light signal S4 that has passed through the low-pass filter unit 53 to a signal level suitable for arithmetic processing (frequency analysis processing) by the arithmetic processing unit 60. Yes, the same circuit as the amplifying unit 55 and the amplification factor changing unit 54 is applied. That is, as shown in FIG. 8, the amplifying unit 58 and the amplification factor changing unit 57 respectively connect the resistors 57A, 57C, and 57C to the feedback path that connects the output and the input − of the operational amplifier 58C in which the resistors 58A and 58B are arranged before and after. The circuit is configured to be connectable via the switching elements 57D, 57E, and 57F, and the amplification factor is changed by controlling the on / off of each of the switching elements 57D to 57F under the control of the arithmetic processing unit 60. .

The input selection unit 61 switches either the light reception signal S3 amplified by the amplification unit 55 or the light reception signal S4 amplified by the amplification unit 58 to the A / D conversion unit 62 under the control of the arithmetic processing unit 60. As shown in FIG. 7, switching elements 61A and 61B are arranged on the output side of the amplifying units 55 and 58, respectively, and the A / D input selection from the arithmetic processing unit 60 is performed on one switching element 61A. A circuit for switching on / off by applying the signal level of the A / D input selection signal SS inverted by an inverter 61C is applied to the other switching element 61B.
The A / D conversion unit 62 receives either the envelope signal S3A or the light reception signal S4 of the light reception signal S3, performs analog-digital conversion, and outputs it to the arithmetic processing unit 60.

  The pseudo external light irradiation unit 25 includes a pseudo external light emitting element 26 and a pseudo external light drive unit 27, and the pseudo external light drive unit 27 emits light for pseudo external light under the control of the arithmetic processing unit 60. The light emission control of the element 26 is performed. As shown in FIG. 8, the pseudo-external light drive unit 27 connects the collector of the transistor 27A to the pseudo-external light light-emitting element 26 through a resistor 27B, grounds the emitter of the transistor 25A, and connects the resistance to the base. A circuit having a configuration in which a control signal (signal to turn on / off) from the arithmetic processing unit 60 is input via the 27C is applied, and the pseudo external light emitting element 26 is selectively driven based on the control signal. The filter driving unit 40 performs display control of the liquid crystal filter 31 under the control of the arithmetic processing unit 60.

  The arithmetic processing unit 60 functions as a control unit that controls each unit of the pulse measuring device 1 and a biological information specifying unit that specifies biological information (pulsation component, body movement component). More specifically, the arithmetic processing unit 60 has a computer configuration including a CPU, a ROM, and a RAM (in this example, having an FFT RAM 1 and an FFT RAM 2), and the CPU is stored in the ROM. By executing the control program, a frequency analysis unit that performs frequency analysis processing (FFT processing) of input data, a pulse rate specification unit that specifies a pulse rate based on the frequency analysis result, and a light transmission amount of the liquid crystal filter 31 It functions as a light transmission amount control unit that controls the above, and performs a process of displaying the specified pulse rate on the display unit 5.

  In the present embodiment, the case where the arithmetic processing unit 60 functions as a control unit, a biological information specifying unit (a frequency analyzing unit, a pulse rate specifying unit), and a light transmission amount control unit by software processing will be described. Instead, some or all of these may be configured by hardware circuits. The arithmetic processing unit 60 also incorporates a clock circuit that measures time based on a frequency-divided signal (1 Hz signal) of an oscillation signal (not shown) of an oscillation circuit. Since a known configuration may be applied to the configuration of the timepiece circuit, detailed description is omitted.

  Next, the operation of the pulse measuring device 1 at the time of pulse measurement (measurement of biological information) will be described. FIG. 9 is a flowchart showing the main operation in this case. As shown in FIG. 9, when the user operates the operation switch 6A to instruct the start of pulse measurement, first, a CPU (hereinafter referred to as a control unit) in the arithmetic processing unit 60 causes an oscillation signal of an oscillation circuit (not shown). Is interrupted (step SP1), and the 32 Hz interrupt is used as a trigger to capture the A / D converter 62 and switch the input by the input selector 61. In addition, the control unit sets the variable N to a value of 0 (step S2), and then causes the light emission control unit 50 to start light emission control of the light emitting element 21 at a time interval of 2 kHz (light emission frequency) with a duty ratio of 50%.

  For this reason, the light receiving signal S1 is output from the light receiving element 22, and is converted into a current voltage by the current-voltage converting unit 51. As shown in FIG. 10A, a light receiving signal S2 that is a modulated wave of 2 kHz (light emitting frequency) Is output. Then, the light reception signal S2 passes through the band-pass filter 52 having a center frequency of 2 kHz, so that a light reception signal S3 indicating a 2 kHz modulation component is output as shown in FIG. 10B. Next, when the detection unit 56 performs detection processing on the light reception signal S3, an envelope signal S3A indicating an envelope of the light reception signal S3 is output as shown in FIG. The waveform of the envelope signal S3A includes information on the pulsation component (pulse waveform) and the body motion component (body motion waveform).

Further, by passing the light reception signal S2 through the low-pass filter unit 53 that passes 10 Hz or less, as shown in FIG. 10D, the light reception signal S4 from which the pulsation component exceeding 10 Hz is removed is acquired. The waveform of the received light signal S4 includes information on body motion components and noise components (such as disturbance light components that do not depend on body motion).
After executing the process of step S2, the control unit sets the A / D input selection signal SS to the H level and waits until the 32 Hz interrupt flag is turned on (step SP4). The 32 Hz interrupt flag is a flag for determining whether or not one period (1/32 second) of the 32 Hz interrupt signal has elapsed. In other words, the 32 Hz interrupt flag is taken in by the A / D converter 62. This is a flag for detecting the timing of input switching.

When the A / D input selection signal SS is set to the H level, the switching element 61A of the input selection unit 61 is set to an open state and the switching element 61B is set to a closed body, so that the envelope signal S3A is It is output to the A / D converter 62, where it is analog-digital converted and output to the arithmetic processor 60.
When the 32 Hz interrupt flag is turned on (step SP4: YES), the control unit clears the 32 Hz interrupt flag (step SP5) and stores the digital data (envelope waveform data) in the FFT RAM 1 (step SP5). SP6).

  Subsequently, the control unit switches the A / D input selection signal SS to the L level, switches the switching element 61A of the input selection unit 61 to the closed state, and switches the switching element 61B to the open state (step SP7). For this reason, the received light signal S4 that has passed through the low-pass filter unit 53 is input to the A / D conversion unit 62, converted from analog to digital, and output to the arithmetic processing unit 60. When the 32 Hz interrupt flag is turned on (step SP8: YES), the control unit clears the 32 Hz interrupt flag (step SP9) and stores the digital data (waveform data of the light reception signal S4) in the FFT RAM 2 ( Step SP10).

  Next, the control unit adds 1 to the variable N (step SP11), and determines whether or not the variable N has reached the value 256 (step SP12). At this time, if the value 256 is not reached (step SP12: NO), the process proceeds to step SP3, and the acquisition of the waveform data of the envelope and the acquisition of the waveform data of the light reception signal S4 are continued. . As a result, the acquisition of these data is repeated until the variable N reaches the value 256, and the acquisition of the data is repeated until the waveform data of each 16 Hz 256 points is stored in the FFT RAM 1 and the FFT RAM 2.

Subsequently, when the variable N reaches the value 256 (step SP12: YES), the control unit performs FFT (Fast Fourier Transform) on the waveform data (the waveform data of the envelope of the light reception signal S3) stored in the FFT RAM 1. ) By executing the process (frequency analysis) (step SP13), as shown in FIG. 11A, an analysis result (first frequency range) that can identify a plurality of frequency spectra (local peaks) included in the waveform Is equivalent to the analysis result of
Next, the control unit performs similar FFT (Fast Fourier Transform) processing (frequency analysis) on the waveform data (waveform data of the light reception signal S4) stored in the FFT RAM 2 (step SP14), As shown in FIG. 11B, an analysis result (corresponding to an analysis result in the second frequency range) that can specify one or a plurality of frequency spectra (local peaks) included in the waveform is obtained.

Here, since the waveform data stored in the FFT RAM 1 includes information on the pulsation component (pulse waveform) and the body motion component (body motion waveform), the two frequency spectra f1 shown in FIG. , F2 corresponds to a pulsation component and a body motion component. However, it is difficult to specify which frequency spectrum f1, f2 is a pulsating component only with this information.
On the other hand, since the waveform data stored in the FFT RAM 2 includes a body motion component and a noise component, and does not include a pulsation component (pulse waveform) exceeding 10 Hz , a large frequency spectrum shown in FIG. It can be seen that f3, f4, and f5 include body motion components and noise components, and do not include pulsation components exceeding 10 Hz .

Therefore, in the present configuration, the control unit utilizes the fact that both the analysis result of the first frequency range and the analysis result of the second frequency range include the frequency spectrum (body motion spectrum) corresponding to the body motion component. Specifies the frequency spectrums f2 and f3 of the same frequency included in both frequency analysis results as body motion components (body motion spectrum) and is included in the analysis result of the first frequency range, but the analysis result of the second frequency range A process (a process for distinguishing) the frequency spectrum f1 that is not included in is identified as a pulsation component (pulsation spectrum) corresponding to the pulse rate (step SP15).

  Next, the control unit determines whether or not the body motion component has been detected (step SP16). If the body motion component has been detected (step SP16: YES), the frequency of the frequency spectrum f1 is determined per minute. The pulse rate is calculated in terms of the number of amplitudes, the calculated pulse rate is displayed on the display unit 5 (step SP17), and the process proceeds to step SP2.

On the other hand, when the body movement component cannot be detected (step SP16: NO), the control unit determines whether or not the pseudo external light irradiation unit 25 is irradiating the pseudo external light L5 (step SP18), and pseudo external light. If the irradiation is not in progress (step SP18: NO), the pseudo-external light driving unit 27 drives the pseudo-external light-emitting element 26 to irradiate the pseudo external light L5 (step SP19). And a control part transfers to the process of step SP2 after pseudo external light L5 irradiation, and repeats the detection process (steps SP2-SP17) of a pulse rate.
For this reason, in the situation where the external light L3 cannot be received in the night time zone or on a cloudy day, the pseudo external light L5 is used instead of the external light L3, and the body movement is obtained by obtaining the analysis result of the second frequency range. It becomes possible to specify the frequency spectrum corresponding to the component (corresponding to the above f3). Accordingly, in this case as well, the control unit specifies the body motion component and the pulsation component by comparing the analysis result of the first frequency range and the analysis result of the second frequency range, as described above. And the pulse rate can be accurately detected.

If it is determined in step S18 that pseudo-external light irradiation is being performed (step SP18: YES), the control unit shifts to the process in step SP2 and executes the processes in steps SP2 to SP16 again. The pulse rate detection process is performed. As a result, if no body motion component happens to be detected, the pulse rate can be accurately detected when the body motion component is detected next time.
In this flowchart, the case is described in which the pulse rate detection process is re-executed when the body motion component cannot be acquired despite the irradiation of the pseudo external light L5 (step SP18: YES). In this case, since it can be determined that there is no body movement, that is, a situation where the user is not exercising, the pulse rate is estimated based only on the analysis result of the first frequency range, and the pulse rate is calculated. You may make it display.

  Specifically, for example, when the frequency spectrum (local peak) obtained from the analysis result of the first frequency range is one and is within the pulse frequency range, the frequency spectrum is used as the pulsation component. There is a method of specifying and displaying the pulse rate from the frequency spectrum. For example, when there are a plurality of frequency spectra (local peaks) obtained from the analysis result of the first frequency range, a frequency spectrum within the frequency range of the pulse is extracted from these frequency spectra. There is a method of calculating and displaying the pulse rate from this frequency spectrum.

By the way, in this embodiment, since the light L2 and the external light L3 (or pseudo external light L5) of the light emitting element 21 are received by the single light receiving element 22, it is received when strong external light L3 such as direct sunlight is received. The element 22 may be electrically saturated. In such a case, a frequency spectrum cannot be obtained even if frequency analysis is performed, and the pulse rate cannot be measured accurately during that time.
Therefore, in this embodiment, the light transmission amount of the liquid crystal filter 31 is variably controlled in order to avoid saturation of the output of the light receiving element 22. FIG. 12 is a flowchart showing the operation in this case, and FIGS. 13A to 13D are views showing the display state of the liquid crystal filter 31 when the external light L3 is received (during the non-irradiation of the pseudo external light L5). is there. The light transmission amount variable control is a process executed during the pulse measurement process including the above steps SP1 to SP19, and the light transmission amount variable control will be described below with reference to FIGS.

At the start of the pulse measurement process, the control unit first controls display of all the pixels of the liquid crystal filter 31 to white (maximum transmission) as shown in FIG. 13A (step SP31), and sets the variable DI to 0 ( (Zero) (step SP32).
Next, the control unit calculates the level average value of the frequency spectrum in the entire frequency band in the first frequency range (hereinafter referred to as the total frequency average level PAVE) from the analysis result of the first frequency range obtained by the process of step SP13. (Step SP33). This all-frequency average level PAVE corresponds to the light-receiving average level of the light-receiving element 22, and the control unit sets the all-frequency average level PAVE within a predetermined frequency range (0.2 Hz to 0.4 Hz in this example). It is determined whether or not there is a peak (frequency spectrum) exceeding (step SP34), and thereby it is determined whether or not the light receiving element 22 is saturated with a large amount of external light L3.

That is, when the light amount of the external light L3 is large and the light receiving element 22 is saturated, since only the DC level is obtained even if the frequency analysis is performed, no peak (frequency spectrum) appears, and the determination in step SP34 is as follows. It becomes NO, and the saturation of the light receiving element 22 can be detected only by the analysis result in the first frequency range.
In this case, the control unit proceeds to the processing of the subsequent step SP35, adds the value 1 to the variable DI, and all the one column of the data column (here, = 1) corresponding to the data electrode D1 of the liquid crystal filter 31 is black ( Display control is performed (non-transparent) (step SP36), and the process proceeds to step SP33.
For this reason, until a peak (frequency spectrum) exceeding the entire frequency average level PAVE is generated within 0.2 Hz to 0.4 Hz of the first frequency range, that is, until the amount of light received by the light receiving element 22 is equal to or lower than the saturation level. The value DI is incremented by 1 to the variable DI, and the liquid crystal filter 31 further turns the data string corresponding to the data electrode D2 to black as shown in FIG. 13C, and then, as shown in FIG. The data string corresponding to the data electrode D3 is made black, and so on. If the peak is present (step S4: YES), it can be determined that the amount of light received by the light receiving element 22 has become equal to or lower than the saturation level. The display state at that time is held.

  As described above, in this configuration, as shown in FIGS. 13A to 13D, the liquid crystal filter 31 mainly corresponds to the incident region of the external light L3 until the light receiving amount of the light receiving element 22 is equal to or lower than the saturation level. The black data is sequentially changed to black from the 3 o'clock side data string (data electrode D1 side). For this reason, it is possible to gradually increase the black region (non-transmissive region) while leaving the light transmissive region in the central region corresponding to the incident region of the reflected light L2 of the light L1 emitted from the light receiving element 22. Therefore, the transmission amount of the external light L3 can be gradually reduced without substantially reducing the transmission amount of the light L2 of the light emitting element 21. Therefore, it is possible to receive the reflected light L2 including pulsation information at an appropriate level while avoiding saturation of the light receiving element 22 due to strong external light L3, and to continue accurate body movement measurement and pulse measurement.

  On the other hand, when the pseudo external light L5 is irradiated, the control unit mainly moves the liquid crystal filter 31 to the 9 o'clock side corresponding to the incident area of the pseudo external light L5 as shown in FIGS. Are sequentially changed to black from the data string (on the data electrode D6 side), whereby the transmission amount of the pseudo external light L5 can be gradually decreased without substantially decreasing the transmission amount of the reflected light L2. Therefore, when the amount of received light of the pseudo external light L5 becomes excessive, for example, even when the amount of received light becomes excessive due to the relationship between the light amount of the pseudo external light L5 and the color of the user's skin, etc. Saturation can be avoided, and accurate body motion measurement and pulse measurement can be continued.

  As described above, in the pulse measuring device 1 of the present embodiment, the single light emitting element 21 that irradiates the light L1 at a predetermined time interval (corresponding to the light emission frequency) and the light L1 can be received through the living body. In addition, the reflection of the light L1 from a single light receiving element 22 provided so as to be able to receive external light L3 whose amount of received light changes in conjunction with body movements of the living body, and a light receiving signal output from the light receiving element 22. A band-pass filter unit 52 that extracts a signal component in the first frequency range corresponding to the light reception component of the light L2, and a low-pass filter unit 53 that extracts a signal component in the second frequency range corresponding to the light reception component of the external light L3. Therefore, the frequency spectrum f1, f2 corresponding to either the pulsation component or the body motion component is specified from the signal component in the first frequency range, and the frequency of the body motion component f3 from the signal component in the second frequency range Special spectrum To, pulsating component f1 and the body motion component f2 (= f3) can be accurately detected.

  In addition, in this configuration, a liquid crystal filter 31 is provided that is disposed on the light receiving portion 22A side of the light receiving element 22 and can change the amount of light transmitted toward the light receiving portion 22A, and the light receiving amount of the light receiving element 22 is less than a saturation level. Since the light transmission amount of the liquid crystal filter 31 is lowered until the time is reached, the pulse measurement can be performed while suppressing the saturation of the light receiving element 22. In this case, in this configuration, the liquid crystal filter 31 reduces the light transmission amount from a region different from the region where the light L2 of the light emitting element 21 is incident, that is, transmits light from the incident region of the external light L3 (or pseudo external light L5). By reducing the amount, the transmission amount of the external light L3 (or pseudo external light L5) can be reduced almost without reducing the transmission amount of the light L2 of the light emitting element 21, and thus the light L2 including the pulsation information is appropriately set. By receiving light at the level, accurate body movement measurement and pulse measurement can be continued.

Further, in this configuration, since the pseudo external light irradiating unit 25 that irradiates the pseudo external light L5 instead of the external light L3 is provided, the low-pass filter unit 53 causes the body motion component (body body) even when the external light L3 cannot be received. Dynamic spectrum). Therefore, the pulse rate can be detected with high accuracy regardless of the time zone and place. Further, since the control for changing the light transmission amount of the liquid crystal filter 31 is performed even during the irradiation of the pseudo external light L5, the situation where the light receiving element 22 is saturated by the pseudo external light L5 can be avoided, and this also enables an accurate pulse. Measurement can be continued.
Furthermore, in this configuration, the living body information detection unit 20 only needs to include one light emitting element 21 and one light receiving element 22 respectively, and in addition to that, only one light emitting element 26 for pseudo external light may be provided. The number of light-emitting elements and light-receiving elements can be reduced despite the high pulse detection accuracy compared to those.

Furthermore, in this configuration, the back cover 8 is formed of a light transmissive material, and the light emitting element 21, the light receiving element 22, and the pseudo external light emitting element 26 in the apparatus main body 2 are transmitted through the back cover 8 with the lights L 1 and L 5. Since the back cover 8 can also be used as a light guide member, the light guide member can be used as a separate light guide member. Thus, the number of parts can be reduced. The back cover 8 only needs to pass through a necessary frequency range, and may be formed of a material that transmits only infrared light, for example.
In this configuration, as shown in FIG. 2, the light receiving element 22 is installed at a position where the center of the apparatus main body 10 is removed, thereby shifting the center of gravity of the apparatus main body 10 from the center position. As a result, a gap between the wristband 3 and the wrist X can be easily formed by the user's movement such as swinging the arm, and the external light L3 can be easily received by the light receiving element 22 and the detection accuracy of body movement can be improved. .

Furthermore, in this configuration, since the first filter that extracts only the signal component of the light passing through the living body (the reflected light L2 of the light L1) is configured in the band-pass filter unit 52, the high-frequency component corresponding to the noise component is removed in advance. It is possible.
In addition, since the input selection unit 61 that switches and outputs the first signal component that has passed through the band-pass filter unit 52 and the second signal component that has passed through the low-pass filter unit 53 to the A / D conversion unit 62 is provided. The A / D conversion unit 62 and the arithmetic processing unit 60 (frequency analysis unit) used for signal processing of these signal components can be shared by one, and the number of components can be reduced accordingly.
In the above-described embodiment, the case where the light emission frequency is 2 kHz is exemplified, but the present invention is not limited to this. For example, when a crystal oscillation circuit generally used for a watch is used as the oscillation circuit, it is preferable to use a frequency that is an integer multiple of 2048 Hz or 1024 Hz, which is the frequency division frequency.

Second Embodiment
FIG. 15 is a block diagram of the pulse measuring device 1 according to the second embodiment, and FIGS. 16A to 16D are diagrams illustrating variable control of the liquid crystal filter 31.
The pulse measuring device 1 includes an A / D conversion unit 62A dedicated to a signal (envelope signal S3A) that has passed through the band-pass filter unit 52 and a first frequency analysis unit (FFT) 70A, and a low-pass filter unit. The pulse measuring device 1 according to the first embodiment is different from the pulse measuring device 1 according to the first embodiment in that an A / D conversion unit 62B and a second frequency analysis unit (FFT) 70B dedicated to the signal (light reception signal S4) that has passed through 53 are provided. Since the configuration other than this is substantially the same as that of the first embodiment except for the variable control of the liquid crystal filter 31, the same reference numerals are given, and redundant description is omitted.

  The A / D conversion unit 62A inputs the envelope signal S3A of the received light signal S3 that passes through the bandpass filter unit 52 and is output from the detection unit 56, and analog-digital converts this to the first frequency analysis unit 70A. Output. Then, the first frequency analysis unit 70A performs an FFT (Fast Fourier Transform) process on the input envelope signal S3A data, and outputs the frequency analysis result to the arithmetic processing unit 60.

  The A / D conversion unit 62B receives the received light signal S4 that has passed through the low-pass filter unit 53, converts the received signal S4 from analog to digital, and outputs the converted signal to the second frequency analysis unit 70B. Then, the second frequency analysis unit 70B performs an FFT (Fast Fourier Transform) process on the input data of the received light signal S4, and outputs the frequency analysis result to the arithmetic processing unit 60.

  As described above, in the present embodiment, the A / D conversion unit 62A and the first frequency analysis unit 70A dedicated to the signal that has passed through the bandpass filter unit 52 are provided, and the A dedicated to the signal that has passed through the low-pass filter unit 53 is provided. Since the A / D conversion unit 62A and the second frequency analysis unit 70B are provided, the frequency analysis processing with a large amount of calculation can be performed by the dedicated frequency analysis units 70A and 70B, thereby reducing the burden on the arithmetic processing unit 60 (CPU). can do. As a result, it is possible to employ a CPU having a relatively low calculation capability for the CPU in the calculation processing unit 60, and it is possible to use general-purpose frequency analysis IC chips as the frequency analysis units 70A and 70B.

In addition, as shown in FIGS. 16A to 16D, the pulse measuring device 1 performs drive control of the liquid crystal filter 31, and this drive control is performed when the external light L3 is received and the pseudo external light L5 is received. It is common. More specifically, when there is no peak (frequency spectrum) that exceeds the total frequency average level PAVE, that is, when the amount of light received by the light receiving element 22 exceeds the saturation level, first, the control unit is shown in FIG. As described above, the corner portions of the four sides of the liquid crystal filter 31 are set to the second halftone gradation, and the periphery of the corner portion is set to the first halftone gradation having a light transmittance higher than that of the second halftone. The transmission amount of the light L3 or the pseudo external light L5 is reduced.
Next, as shown in FIG. 16C, the control unit makes each of the halftone areas one level black (high light opacity), and surrounds the first halftone with a surrounding area. Then, the transmission amount of the external light L3 or the pseudo external light L5 is further reduced. If the state in which the amount of received light continues to exceed the saturation level still continues, the halftone areas are each made one level black gradation as shown in FIG. 16D, and the light L2 of the light receiving element 22 is The white area other than the incident central area is made a one-step black gradation.

  In this way, the light transmission amount of the light L2 of the light emitting element 21 is reduced in multiple steps by reducing the light transmission amount of the region (second region) excluding the central region (first region) where the light L2 of the light receiving element 22 is incident. The amount of transmission of the external light L3 and the pseudo external light L5 can be reduced little by little without lowering. Accordingly, it is possible to receive the reflected light L2 including pulsation information at an appropriate level while avoiding saturation of the light receiving element 22 due to strong external light L3, and it is possible to continue accurate pulse measurement. The driving control of the liquid crystal filter 31 may be applied to the pulse measuring device 1 of the first embodiment, and the driving control of the liquid crystal filter 31 of the first embodiment is applied to the pulse measuring device 1 of the second embodiment. Of course, it may be applied.

<Third Embodiment>
FIG. 17 is a block diagram of the pulse measuring device 1 according to the third embodiment, and FIGS. 18A to 18H are diagrams showing variable control of the liquid crystal filter 31. FIG.
This pulse measuring device 1 is an optical pulse measuring device that irradiates the user's finger (detection site) X2 with the light L1 of the light emitting element 21 and receives the reflected light L2 with the light receiving element 22, and has an amplification factor. The point which is not provided with the change parts 54 and 57 differs from the pulse measuring device 1 which concerns on the said 2nd Embodiment. Since the other configuration is substantially the same as that of the second embodiment except for the variable control of the liquid crystal filter 31, the same reference numerals are given, and redundant description is omitted.
In this pulse measuring device 1, the amplification factors 55 and 58 are fixed to a predetermined constant value. This fixed value is set to a value that is most appropriate when pulse waves are measured in various environments. According to this configuration, it is possible to reduce the number of components compared to the first embodiment and the second embodiment because the amplification factor changing unit or the like for changing the amplification factor of the amplification units 55 and 58 is not provided. The burden on the arithmetic processing unit 60 (CPU) can be reduced.

In addition, as shown in FIGS. 18A to 18H, the pulse measuring device 1 performs drive control of the liquid crystal filter 31, and this drive control indicates when the external light L3 is received. As shown in these figures, the control unit corresponds to the incident region of the external light L3 when there is no peak (frequency spectrum) exceeding the total frequency average level PAVE, that is, when the amount of light received by the light receiving element 22 exceeds the saturation level. The transmission amount is gradually reduced from the 3 o'clock side. Specifically, as shown in FIG. 18B, the control unit first changes the two corners on the 3 o'clock side to the second halftone gradation and surrounds the two corners (substantially). 9 o'clock side) is set to the first halftone gradation having a light transmittance higher than that of the second halftone, and the transmission amount of the external light L3 is reduced.
Next, as shown in FIG. 18C, the control unit makes each of the halftone areas a one-step black (high light opacity) gradation and surrounds the first halftone gradation around it. The amount of transmission of the external light L3 is further reduced. If the state in which the amount of received light continues to exceed the saturation level continues, the halftone area is set to a one-step black gradation, as shown in FIGS. The display is sequentially changed so that the hour side is set to the first halftone gradation and the transmission amount of the external light L3 is reduced.

That is, by gradually increasing the gradation from the 3 o'clock side corresponding to the incident region of the external light L3, a light transmitting region is provided in the central region corresponding to the incident region of the reflected light L2 of the light L1 emitted from the light receiving element 22. The black area (non-transmission area) and the halftone area are gradually increased while leaving the light amount, and the transmission amount of the external light L3 can be gradually reduced without substantially reducing the transmission amount of the light L2 of the light emitting element 21. Accordingly, it is possible to receive the reflected light L2 including pulsation information at an appropriate level while avoiding saturation of the light receiving element 22 due to the strong external light L3, and it is possible to continue accurate pulse measurement.
In this case, compared with the method of gradually increasing only the black region of the first embodiment, the amount of transmission of the external light L3 can be gradually reduced more finely. Therefore, the external light L3 is stronger than that of the first embodiment. While avoiding saturation of the light receiving element 22, the reflected light L2 including the pulsation information can be received at a more appropriate level, and more accurate pulse measurement can be continued.

On the other hand, when the pseudo external light L5 is emitted, although not shown in the drawing, the control unit performs a liquid crystal filter so that the gradation is gradually increased from the 9 o'clock side corresponding to the incident area of the pseudo external light L5. 31 is controlled. That is, drive control is performed so that FIGS. 18A to 18D are performed symmetrically. As a result, the amount of transmission of the pseudo external light L5 can be gradually and more gradually reduced than in the first embodiment, and the reflected light L2 including pulsation information can be further reduced while avoiding saturation of the light receiving element 22 by the pseudo external light L5. Light can be received at an appropriate level, and accurate pulse measurement can be continued.
The drive control of the liquid crystal filter 31 may also be applied to the pulse measuring device 1 of the first or second embodiment, or the first or second of the pulse measuring device 1 of the third embodiment. Of course, the drive control of the liquid crystal filter 31 of the embodiment may be applied.

Further, the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention. For example, in the above-described embodiment, the average frequency level PAVE is obtained from the analysis result of the first frequency range, and it is determined whether or not a predetermined level peak exists based on the total frequency average level PAVE. The case of detecting whether or not the element 22 is saturated has been described. However, the present invention is not limited to this, and the same processing is performed from the analysis result of the second frequency range to detect whether or not the light receiving element 22 is saturated. May be.
However, the saturation of the light receiving element 22 is determined from the information of the first frequency range including the former pulse wave component rather than the saturation of the light receiving element 22 from the information of the second frequency range not including the latter pulse wave component. Is preferred. The reason is that the former is considered to be efficient from the viewpoint of accurately detecting the pulse wave component because it directly determines the presence or absence of a peak that is expected to correspond to the pulse wave component.

Further, the method is not limited to the method of detecting the saturation of the light receiving element 22 using the frequency analysis result described above. For example, the light receiving element 22 is based on the output level (light receiving level) or the average output level (light receiving average level) of the light receiving element 22. Other methods such as detecting whether or not is saturated may be applied.
In the above-described embodiment, the case where the light transmission amount variable filter is configured by the liquid crystal filter 31 has been described. However, the present invention is not limited to this, and other optical filters and optical shutters that can limit the transmitted light by wavelength or polarization. Or the like. However, the liquid crystal filter is preferably employed in that it consumes less current and can be downsized because it does not require a mechanical mechanism.

Moreover, although the above-mentioned embodiment demonstrated the case where the control program for performing control of light transmission variable filters, such as the liquid crystal filter 31, and a pulse measurement process was memorize | stored in the pulse measuring device 1 previously, The control program may be stored in a computer-readable recording medium such as a magnetic recording medium, an optical recording medium, or a semiconductor recording medium, and the computer may read the control program from the recording medium and execute it. The control program may be downloaded from a distribution server on the communication network.
Moreover, although the above-mentioned embodiment demonstrated the case where this invention was applied to a wristwatch-type pulse measuring device, it is not restricted to this. For example, an optical sensor unit (corresponding to a biological information detection unit) provided with a light emitting element 21 and a light receiving element 22 is attached to a blood flow site of a living body such as a person or an animal, and the other configurations are separate pulses. It can be widely applied to measuring devices and the like. In addition, the blood flow site for pulse detection is not limited to the wrist and fingers, but may be the ear. Furthermore, the present invention is not limited to the pulse measurement device, and can be widely applied to optical biological information measurement devices such as a body motion measurement device that outputs (displays) a detection result of body motion (body motion pitch or the like).

It is a figure which shows the pulse measuring device which concerns on 1st Embodiment of this invention. It is a figure which shows the internal structure of a pulse measuring device. (A) is a figure which shows the layout of a liquid crystal filter, (B) is a figure which shows the cross-section of a liquid crystal filter. (A) is a plan view of the TFT layer of the liquid crystal filter, (B) is a perspective view showing the TFT layer together with its peripheral configuration, and (C) is a partially enlarged view of the TFT layer. It is a figure which shows the electrode structure of a TFT layer. It is a figure which shows an example of the drive waveform of a liquid crystal filter. It is a block diagram of a pulse measuring device. It is a figure which shows the circuit structure of a pulse measuring device. It is a flowchart which shows the main operation | movement at the time of a pulse measurement. (A)-(D) are figures which show the signal waveform of each part in a pulse measuring device. (A) is a figure which shows the frequency analysis result of the signal which passed the band pass filter part, (B) is a figure which shows the frequency analysis result of the signal which passed the low-pass filter part. It is a flowchart which shows the light transmission amount variable control of a liquid crystal filter. (A)-(D) is a figure which respectively shows the display state of the liquid crystal filter at the time of external light light reception. (A)-(D) is a figure which respectively shows the display state of the liquid crystal filter at the time of pseudo external light light reception. It is a block diagram of the pulse measuring device concerning a 2nd embodiment of the present invention. (A)-(D) are figures which respectively show the display state of a liquid crystal filter. It is a block diagram of the pulse measuring device concerning a 3rd embodiment of the present invention. (A)-(H) are the figures which respectively show the display state of the liquid crystal filter at the time of external light light reception.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Pulse measuring device (biological information measuring device), 2 ... Apparatus main body, 3 ... Wristband, 5 ... Display part, 7 ... Outer case, 8 ... Back cover, 20 ... Biological information detection part, 21 ... Light emitting element, 22 DESCRIPTION OF SYMBOLS ... Light receiving element, 31 ... Liquid crystal filter, 32 ... Light shielding member, 40 ... Filter drive part, 50 ... Light emission control part, 51 ... Current-voltage conversion part, 52 ... Band-pass filter part (1st filter), 53 ... Low-pass Filter unit (second filter), 54, 57 ... amplification factor changing unit, 55, 58 ... amplifying unit, 56 ... detecting unit, 60 ... calculation processing unit (biological information specifying unit, frequency analyzing unit, pulse rate specifying unit, control) Part, light transmission amount control part), 61 ... input selection part, 62 ... A / D conversion part, f1 to f6 ... frequency spectrum.

Claims (12)

A light emitting element that emits light toward a detection site of a living body;
A light receiving element that receives the light through the living body and generates a light reception signal;
A light transmission variable filter that increases or decreases the transmission of light incident on the light receiving element;
A light transmission amount control unit for controlling the light transmission amount of the light transmission amount variable filter;
Among the received light signals, a frequency analysis is performed on the waveform data of the envelope of the first signal component in the first frequency range including the light emission frequency of the light to identify a plurality of frequency spectra, and the first frequency range and pulse Frequency analysis is performed on the waveform data of the second signal component in the second frequency range lower than the frequency corresponding to the number to identify the frequency spectrum, and the frequency spectrum included in the first signal component and the second signal component include A biological information specifying unit that specifies a pulsation component corresponding to the pulse rate based on the frequency spectrum that is not ,
The biological information specifying unit includes the same frequency included in both the plurality of frequency spectra obtained from the waveform data of the envelope of the first signal component and the frequency spectrum obtained from the waveform data of the second signal component A frequency analysis unit that executes processing for specifying the frequency spectrum of
When the biological information specifying unit cannot specify the frequency spectrum of the same frequency, the light receiving element has a pseudo external light irradiating unit that emits pseudo external light that can be received in conjunction with body movement of the living body. A biological information measuring device. The biological information measuring apparatus according to claim 1,
The biological information measurement device, wherein the light transmission amount control unit lowers the light transmission amount of the variable light transmission amount filter from the maximum transmission state until the light reception amount of the light receiving element becomes a saturation level or less. The biological information measuring device according to claim 1 or 2,
The biological information specifying unit includes the same frequency included in both the plurality of frequency spectra obtained from the waveform data of the envelope of the first signal component and the frequency spectrum obtained from the waveform data of the second signal component A frequency analysis unit that executes processing for specifying the frequency spectrum of
When the frequency analysis unit specifies the frequency spectrum of the same frequency, the pulsation component corresponding to the pulse rate from the frequency spectrum excluding the frequency spectrum of the same frequency among the frequency spectrum included in the first signal component. A biological information measuring apparatus comprising: a pulse rate specifying unit that specifies a corresponding pulse wave spectrum and specifies a pulse rate from the pulse wave spectrum. The biological information measuring device according to claim 3,
The light transmission amount control unit obtains a light reception average level from the frequency analysis result of the first signal component by the frequency analysis unit, and a peak of a predetermined level exists in the frequency analysis result based on the light reception average level. Or not, and the light transmission amount of the light transmission amount variable filter is lowered below the maximum transmission state until the peak exists. The biological information measuring device according to any one of claims 2 to 4,
The biological information specifying unit includes a low-pass filter that extracts a second signal component of the second frequency range by passing through the body motion frequency range of the living body in the received light signal. Measuring device. In the biological information measuring device according to any one of claims 2 to 5,
The light transmission amount control unit lowers the light transmission amount of a second region different from the first region where the light of the light emitting element is incident from the light transmission amount variable filter from a maximum transmission state. Information measuring device. The biological information measuring apparatus according to claim 6,
The biological transmission measuring device, wherein the light transmission amount control unit increases a halftone region or a non-transmission region with respect to the second region of the light transmission amount variable filter. In the biological information measuring device according to claim 6 or 7,
The biological information measuring apparatus according to claim 1, wherein the first region is a central region in plan view of the light transmission amount variable filter. In the biological information measuring device according to any one of claims 1 to 8,
The biological information measuring device, wherein the light transmission variable filter is a transmissive liquid crystal panel. In the biological information measuring device according to any one of claims 1 to 9,
The biological information specifying unit includes a band-pass filter that extracts a first signal component in the first frequency range by passing a frequency range having a light emission frequency of the light of the received light signal as a substantially central frequency. A biological information measuring device as a feature. In the biological information measuring device according to any one of claims 1 to 10,
  The biological information measuring apparatus, wherein the light emitting element emits infrared light having a single peak wavelength or red light having a single peak wavelength. Irradiate light toward the detection part of the living body,
  The light receiving element receives the light via the living body and generates a light reception signal, and the light transmission amount control unit controls the light transmission amount of the light transmission variable filter through which the light incident on the light receiving element is transmitted.
  Among the received light signals, a frequency analysis is performed on the waveform data of the envelope of the first signal component in the first frequency range including the light emission frequency of the light to identify a plurality of frequency spectra, and the first frequency range and pulse Frequency analysis is performed on the waveform data of the second signal component in the second frequency range lower than the frequency corresponding to the number to identify the frequency spectrum, and the frequency spectrum included in the first signal component and the second signal component include Based on the frequency spectrum that does not exist, execute the process to identify the pulsation component corresponding to the pulse rate,
  In the process of identifying the pulsation component corresponding to the pulse rate, the plurality of frequency spectra obtained from the waveform data of the envelope of the first signal component, and the frequency spectrum obtained from the waveform data of the second signal component To identify the frequency spectrum of the same frequency contained in both
  When the frequency spectrum of the same frequency cannot be specified, the living body information measuring device, wherein the light receiving element emits the pseudo outside light that can be received in conjunction with the body movement of the living body by the pseudo outside light irradiation unit. Control method.

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