JP6996150B2 - Pulse wave detector - Google Patents

Description

The present disclosure relates to a pulse wave detection device that detects a pulse wave by irradiating a living body as an observation target with light.

Conventionally, a light emitting element is used to irradiate a living body as an observation target with light, and the reflected light from the living body is received by the light receiving element, and a pulse wave is obtained based on a change in the intensity of the received reflected light over time. A so-called optical pulse wave detection device that detects light is known. The pulse wave here represents a wave-like pressure fluctuation of blood in a blood vessel generated according to a heartbeat.

Since such an optical pulse wave detection device detects a pulse wave by utilizing the absorption characteristic of blood components, it is necessary to remove the influence of ambient light such as sunlight when using it outdoors. Occurs. In Patent Document 1, in order to suppress the influence of ambient light, the light receiving intensity of the reflected light when the light emitting element is made to emit light to a living body at a normal level is used to reduce the light emitting element to half the normal level (hereinafter, dimming). A configuration is disclosed in which a value obtained by subtracting the light receiving intensity of the reflected light when the light is emitted at the level) is adopted as a parameter indicating a pulse component (hereinafter referred to as a pulse wave index value).

Japanese Unexamined Patent Publication No. 2008-13202

In the configuration of Patent Document 1, if the intensity of ambient light is constant, the amount of ambient light equal to each of the light intensity when emitting light at a normal level and the light receiving intensity when emitting light at a dimming level is equal. Contains ingredients. Therefore, the ambient light component can be removed by taking the difference between the two. That is, according to the configuration of Patent Document 1, if the intensity of the disturbance light is constant, it is possible to suppress that the pulse wave index value includes an error due to the disturbance light.

However, the intensity of ambient light can change over time (in other words, dynamically). Further, the timing of acquiring the light receiving intensity at the time of light emission at the normal level and the timing of acquiring the light receiving intensity at the time of light emission at the dimming level are different timings.

Therefore, it is assumed that the size of the disturbance light component included in the light receiving intensity at the normal level and the size of the disturbance light component included in the light receiving intensity at the dimming level are different. That is, in the configuration disclosed in Patent Document 1, there is a problem that an error occurs in the disturbance component due to the time difference in the detection timing of the light receiving intensity, and it is not possible to obtain an accurate pulse wave waveform.

The present disclosure has been made based on this circumstance, and an object thereof is to provide a pulse wave detection device capable of detecting a pulse wave with higher accuracy.

In the present disclosure for achieving the purpose, the index value calculation process for calculating the pulse wave index value indicating the state of the blood vessel of the living body by irradiating the living body as an observation target with light is sequentially executed in a predetermined sampling cycle. , A pulse wave detection device that detects the pulse wave of a living body based on the time change of the pulse wave index value, and has a configuration that controls the operation of a light emitting unit that irradiates light, and performs one index value calculation process. The light emitting control unit is composed of a light emitting control unit (F1) that irradiates the light emitting unit with light a predetermined number of times and a light receiving unit (3) that outputs a light receiving intensity that is the intensity of the light coming from the direction in which the light emitting unit irradiates the light. The light receiving intensity acquisition unit (F21) that acquires the light receiving intensity when the light emitting unit is irradiated with light as the irradiation intensity, and the light receiving intensity when the light emitting unit is not irradiating light, and is the light emitting control unit. Is the pre-irradiation intensity acquisition unit (F22) that acquires the light-receiving intensity before irradiating the light-emitting unit with light as the pre-irradiation intensity, and the light-receiving intensity when the light-emitting unit is not irradiating light. The post-irradiation intensity acquisition unit (F23) that acquires the light-receiving intensity after irradiating the light-emitting unit with light as the post-irradiation intensity, and each time the light-emitting control unit irradiates the light-emitting unit with light, the irradiation corresponding to the irradiation Each time the pre-differential intensity calculation unit (F31), which calculates the pre-differential intensity, which is the value obtained by subtracting the pre-irradiation intensity corresponding to the irradiation from the intensity, and the light emission control unit irradiate the light emitting unit with light, the irradiation is performed. The post-differential intensity calculation unit (F32), which calculates the post-differential intensity, which is the value obtained by subtracting the post-irradiation intensity corresponding to the irradiation from the corresponding irradiation intensity, and the light emission control unit emit light in one index value calculation process. An index value calculation unit that calculates the value obtained by adding the front difference intensity calculated by the front difference intensity calculation unit and the rear difference intensity calculated by the rear difference intensity calculation unit as a pulse wave index value each time the unit is irradiated with light ( F3), and the index value calculation unit adjusts the number of times of light emission, which is the number of times the light emitting unit emits light in one index value calculation process, so that the pulse wave index value changes at a predetermined target level. It is characterized by including a number adjustment unit (F7) .

In the above configuration, the index value generation unit generates a pulse wave index value by adding the front difference strength calculated by the front difference strength calculation unit and the back difference strength calculated by the back difference strength calculation unit. The pre-difference intensity calculated by the pre-difference intensity calculation unit includes the change over time of the disturbance light component derived from the time difference from the time when the pre-irradiation intensity used for calculating the pre-difference intensity is acquired to the time when the pre-irradiation intensity is acquired. Minutes are included as an error. In addition, the posterior difference intensity calculated by the posterior difference intensity calculation unit includes the disturbance light component derived from the time difference from the time when the intensity at the time of irradiation is acquired to the time when the intensity after irradiation used for calculating the posterior difference intensity is acquired. The amount of change over time is included as an error.

In such a configuration, when the intensity of the disturbance light increases monotonically in the time zone before and after the light emitting portion emits light, the disturbance light component included in the front difference intensity when the front difference intensity and the back difference intensity are added together. And the error of the disturbance light component included in the post-differential intensity are offset. Similarly, when the intensity of the disturbance light decreases monotonically over time in the time zone before and after the light emission, the error of the disturbance light component included in the front difference intensity and the error of the disturbance light component included in the back difference intensity also occur. And act to cancel each other out.

Therefore, the error caused by the change over time of the disturbance light included in the pulse wave index value calculated by the index value calculation unit is suppressed to a relatively small value. As a matter of course, the smaller the error caused by the disturbance light included in the pulse wave index value, the more accurate the pulse wave waveform can be obtained. That is, according to the above configuration, the pulse wave can be detected more accurately.

The reference numerals in parentheses described in the claims indicate, as one embodiment, the correspondence with the specific means described in the embodiments described later, and limit the technical scope of the present disclosure. is not it.

It is a block diagram which shows the schematic structure of the pulse wave detection apparatus 100 which concerns on embodiment. It is a functional block diagram which shows the schematic structure of the control unit 1. It is a figure for demonstrating the index value calculation process. It is a flowchart of index value calculation processing. It is a figure for demonstrating the effect of the calculation method of a sub-index value in this embodiment. It is a figure which shows the relationship between the light emission frequency K and the transition level and the amplitude of a pulse wave index value M. It is a flowchart of biometric information identification processing. It is a flowchart of a setting change process. It is a flowchart of the light emission number adjustment process. It is a figure for demonstrating the operation of the light emission number adjustment part F7. It is a figure for demonstrating the operation of the light emission number adjustment part F7. It is a figure for demonstrating the operation of the light emission number adjustment part F7. It is a figure for demonstrating operation of a comparative structure. It is a figure for demonstrating the influence which the change with time of the disturbance light component has on the sub-index value in a comparative composition. It is a figure for demonstrating the operation of the control part 1 in the modification 1. FIG. It is a figure for demonstrating the operation of the control part 1 in the modification 5.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. FIG. 1 is a diagram showing an example of a schematic configuration of the pulse wave detection device 100 according to the present disclosure. The pulse wave detection device 100 is a device that measures (in other words, detects) a pulse wave signal indicating a pulse wave of an observation target by irradiating a predetermined portion 200 of a person's body as an observation target with light. More specifically, the pulse wave signal is a signal representing a pulse wave fluctuation component that fluctuates by reflecting the pulse wave to be observed.

As shown in FIG. 1, the pulse wave detection device 100 includes at least a control unit 1, a light emitting module 2, and a light receiving module 3. Further, as a more preferable embodiment in the present embodiment, the pulse wave detection device 100 includes an acceleration sensor 4, an operation unit 5, a display unit 6, a wireless communication module 7, and a charging unit 8. The light emitting module 2, the light receiving module 3, the acceleration sensor 4, the operation unit 5, the display unit 6, the wireless communication module 7, and the charging unit 8 are each electrically communicable with the control unit 1. It should be noted that the mode of being electrically connected includes a mode of being connected so as to be capable of bidirectional or unidirectional communication.

In the pulse wave detection device 100, all the above-mentioned components may be housed in one housing, or may be divided into two or more housings. The pulse wave detection device 100 may be configured so that the entire pulse wave detection device 100 is attached to the body of a person (hereinafter referred to as a user) as an observation target and used. Further, only a part of the body may be worn on the user's body. Examples of the component to be worn on the user's body include a light emitting module 2 and a light receiving module 3. Further, when the pulse wave detection device 100 includes the acceleration sensor 4, the acceleration sensor 4 also corresponds to the configuration to be worn on the user's body. Examples of the body part of the user who wears a part or all of the pulse wave detection device 100 include wrists, arms, torso, legs, neck, and head.

In the present embodiment, as an example, in the pulse wave detection device 100, all the components are housed in one housing, and it is assumed that the pulse wave detection device 100 is worn on the wrist of the user and used. That is, it is assumed that the pulse wave detection device 100 is configured as a wristwatch type or wristband type wearable device.

The control unit 1 is configured to generate the above-mentioned pulse wave signal by controlling the operation of the pulse wave detection device 100. Further, the control unit 1 of the present embodiment identifies the peak interval, the presence / absence of fluctuation of the peak interval, the envelope waveform, etc. by analyzing the pulse wave signal, as will be described in detail later, and determines the user's state. It also has a function to identify.

The control unit 1 is configured as a computer. That is, the control unit 1 includes a CPU 11, a RAM 12, a ROM 13, an I / O 14, and a bus line connecting these configurations. The CPU 11 may be realized by using, for example, a microprocessor or the like. The number of CPUs 11 included in the control unit 1 may be one or a plurality. Further, the control unit 1 may be realized by using a GPU or an MPU instead of the CPU 11. Further, it may be realized by combining a CPU, GPU, and MPU. The I / O 14 is an interface for the control unit 1 to input / output data with other configurations included in the pulse wave detection device 100. The I / O 14 may be realized by using an IC, a digital circuit element, an analog circuit element, or the like.

The ROM 13 stores a program (hereinafter referred to as a pulse wave detection program) for causing a normal computer to function as the control unit 1. The pulse wave detection program described above may be stored in a non-transitionary tangible storage medium such as ROM 13. The pulse wave detection program may be stored in the flash memory instead of the ROM 13. Executing the pulse wave detection program by the CPU 11 corresponds to executing the method corresponding to the pulse wave detection program.

The control unit 1 provides a function corresponding to various functional blocks shown in FIG. 2 by the CPU 11 executing the above-mentioned pulse wave detection program. That is, the control unit 1 is a functional block such as a light emission control unit F1, a light receiving intensity acquisition unit F2, a pulse wave index value calculation unit F3, a specific target setting unit F4, a target level setting unit F5, and an A / D conversion setting change unit F6. It includes a light emission frequency adjusting unit F7, a biological information specifying unit F8, and a presentation processing unit F9. The light-receiving intensity acquisition unit F2 includes a light-emitting intensity acquisition unit F21, a pre-emission intensity acquisition unit F22, and a post-emission intensity acquisition unit F23 as finer functions (in other words, sub-functions). The pulse wave index value calculation unit F3 includes a front difference intensity calculation unit F31 and a rear difference intensity calculation unit F32 as more detailed functions (in other words, sub-functions). Details of these functions will be described later. The light emitting intensity acquisition unit F21, the pre-irradiation intensity acquisition unit F22, and the post-irradiation intensity acquisition unit F23 correspond to the irradiation intensity acquisition unit, the pre-irradiation intensity acquisition unit, and the post-irradiation intensity acquisition unit according to claim in order. The A / D conversion setting change unit F6 corresponds to the conversion unit setting change unit described in claim.

The method for realizing these functions constituting the control unit 1 is not limited to software, and some or all of the functions may be realized by using hardware that combines logic circuits, analog circuits, and the like. good. The embodiment realized by using hardware includes one embodiment or an embodiment realized by using an IC.

The light emitting module 2 includes a light emitting diode (hereinafter, LED: Light Emitting Diode) 21 and a drive circuit 22. The drive circuit 22 is a circuit that energizes the LED 21 and irradiates (in other words, emits light) light having a predetermined pulse width according to an instruction from the control unit 1. The light emitted by the LED 21 is preferably visible light. For example, light having a wavelength of 5000 Å to 7000 Å may be used. According to the configuration for detecting the pulse wave using visible light, the user can visually recognize whether or not the pulse wave detection device 100 is operating based on the light emitted from the LED 21. As another aspect, the LED 21 may be an infrared LED that outputs near infrared rays or the like.

The light emitting module 2 is configured to irradiate a predetermined portion 200 of the user with light in a predetermined method of using the pulse wave detection device 100. The light emitting module 2 corresponds to the light emitting unit according to claim. The portion 200 to be irradiated with light by the light emitting module 2 (hereinafter referred to as the irradiation portion) 200 may be appropriately selected, and for example, a wrist, a finger, an ankle, neck, forehead, or the like can be adopted. The irradiation site 200 is preferably a site where wave-like pressure fluctuations of blood in the blood vessel, which are generated according to the heartbeat, are relatively likely to occur.

The pulse wave detection device 100 of the present embodiment is configured on the assumption that it is worn on the wrist of the user and used. Therefore, the irradiation site 200 is the wrist. When a wrist is adopted as the irradiation site 200, the light emitting module 2 in the pulse wave detection device 100 may be configured to irradiate light from an irradiation window provided on a surface in contact with the user's wrist. The appearance configuration and usage of the pulse wave detection device 100 may be appropriately designed according to the irradiation site. A part of the light emitted by the LED 21 is reflected in the capillaries of the skin.

The light receiving module 3 includes a photodiode (hereinafter PD: Photodiode), a current-voltage conversion unit (hereinafter I / V conversion unit) 32, and an analog-to-digital conversion unit (hereinafter A / D conversion unit) 33. The light receiving module 3 corresponds to the light receiving unit according to claim. The PD 31 is a light receiving element that receives light in a wavelength band including the light emitted by the LED 21, converts it into an electric signal, and outputs the light. As the light receiving element, for example, a phototransistor may be used.

The PD 31 outputs a current signal according to the amount of received light. The PD 31 is configured to receive the light reflected by the blood (more specifically, hemoglobin) in the capillaries among the light emitted by the LED 21. For example, the PD 31 is arranged at a position adjacent to the LED 21 so as to receive light arriving from the irradiation direction of the LED 21.

The PD 31 has a function of receiving the light reflected in the capillaries among the light emitted by the LED 21 and extracting it as an electric signal. The extracted electric signal is a signal including a pulse wave fluctuation component that fluctuates reflecting the pulse wave of the user. The I / V conversion unit 32 converts the current signal output by the PD 31 into a voltage signal and outputs it to the A / D conversion unit 33.

The A / D conversion unit 33 is configured to output data obtained by quantizing an analog voltage signal input from the I / V conversion unit 32 with a predetermined resolution (in other words, the number of bits). That is, a well-known analog-digital (hereinafter, A / D: Analog to Digital) conversion process is performed. The data output by the A / D conversion unit 33 indicates the magnitude of the amount of received light. The A / D conversion unit 33 performs A / D conversion based on an instruction from the control unit 1. The A / D conversion unit 33 of the present embodiment is a ΔΣ type A / D converter that performs A / D conversion using ΔΣ modulation. As another aspect, the A / D conversion unit 33 may be a parallel comparison type A / D converter, a sequential comparison type A / D converter, or a follow-up comparison type A / D converter.

The ΔΣ type A / D converter as the A / D conversion unit 33 is a subtraction (that is, Δ) circuit for obtaining the difference between the value of the input signal and a certain fixed voltage value, and the addition of the subtracted results one after another. It can be realized by using a circuit (or an integrating circuit), a comparator that compares the addition result with a reference value, and a switch that operates according to the comparison result (digital value).

The A / D conversion unit 33 is a parameter that controls the operation of the A / D conversion unit 33, and the oversampling rate (hereinafter, OSR: Over-Sampling) is a parameter that the control unit 1 can change the set value. Rate) and the number of bits used. OSR is a parameter that defines the sampling rate. Increasing the OSR improves the accuracy of the A / D conversion, but increases the time required for the A / D conversion.

The number of bits used is a parameter that defines the number of bits used to indicate the value after digital conversion. The larger the number of bits used, the higher the resolution. An upper limit is set in advance for the number of bits used. Here, as an example, it is assumed that the upper limit of the number of bits used is set to 24 bits. The OSR and the number of bits used are changed by the control unit 1.

The acceleration sensor 4 is a sensor that detects acceleration. As the acceleration sensor 4, for example, a sensor having three detection axes orthogonal to each other and measuring acceleration acting in each axis direction (that is, a three-axis acceleration sensor) can be adopted. Of course, as another aspect, the acceleration sensor 4 may be a 2-axis acceleration sensor, a 1-axis acceleration sensor, or the like. The acceleration sensor 4 sequentially outputs data representing the detected acceleration to the control unit 1.

When the pulse wave detection device 100 is attached to the user's body and used as in the present embodiment, the acceleration sensor 4 detects the direction and magnitude of the acceleration according to the movement of the user. Therefore, the acceleration sensor 4 functions as a sensor for detecting the presence or absence of movement of the user. As the sensor for detecting the movement of the user, a gyro sensor may be used instead of the acceleration sensor 4.

The operation unit 5 is configured to accept a user's operation and output a signal corresponding to the operation (hereinafter, an operation signal) to the control unit 1. The user's operation may include, for example, an operation for instructing the execution of the biometric information specifying process described later, an operation for instructing the change of the biometric information to be specified, and the like. The person who operates the operation unit 5 may be a person other than the user. For example, it may be a doctor, a nurse, or the like. The operation unit 5 may be realized by using physically realized buttons, or may be a touch panel laminated on the display unit 6. Further, it may be a voice input device. They may be provided in combination.

The display unit 6 is a device capable of displaying an image. The display unit 6 displays the image input from the control unit 1. The wireless communication module 7 is a communication module for performing wireless communication with the outside. The wireless communication module 7 may be a communication module for directly performing wireless communication with a communication terminal (for example, a smartphone) carried by a user, or may be a communication for communicating with a server or the like via a wide area communication network. It may be a module. As a communication standard for directly performing wireless communication with a mobile terminal such as a smartphone, Bluetooth (registered trademark) or the like can be adopted. The charging unit 8 is a circuit that supplies electric power to a secondary battery (not shown) included in the pulse wave detection device 100 by being connected to an external power source by wire or wirelessly.

<Index value calculation process>
Next, the index value calculation process executed by the control unit 1 will be described with reference to FIGS. 3 and 4. The index value calculation process is a process of calculating a pulse wave index value M, which is a parameter representing a pulse wave fluctuation component that fluctuates by reflecting a user's pulse wave. The index value calculation process is repeatedly executed every predetermined sampling cycle Ts. Repeatedly performing the index value calculation process is also referred to as sampling hereafter. Sampling is executed, for example, when an operation corresponding to the start of the biometric information specifying process described later is performed.

The pulse wave index value M acquired by one index value calculation process represents the state (volume / pressure) of the blood vessel at a certain time point, as will be described in detail later. Therefore, the graph formed by connecting (in other words, interpolating) the pulse wave index values at a plurality of time points collected by executing the index value calculation process with a straight line or a curve is shown in FIG. 3 (A). And, as shown in (B), the waveform of the pulse wave is represented. The pulse wave index value M corresponds to the pulse wave signal described at the beginning. Note that FIG. 3 is a schematic diagram showing an outline of the index value calculation process, and FIG. 3C shows the operation of the control unit 1 in one index value calculation process.

In one index value calculation process, the light emission control unit F1 of the control unit 1 causes the LED 21 to emit light at least once. Further, the light receiving intensity acquisition unit F2 instructs the A / D conversion unit 33 to perform A / D conversion when and before and after the LED 21 is emitting light, and determines the light receiving intensity at those points. get. When the LED 21 is made to emit light a plurality of times in one index value calculation process, it is made to emit light at a predetermined light emission interval Tp.

The light emission interval Tp is a total value of the light emission duration Tq from the start of light emission of the LED 21 to the turn-off of the LED 21 and the turn-off duration of maintaining the state in which the LED 21 is turned off. According to another viewpoint, the extinguishing duration is the time obtained by subtracting the emission duration Tq from the emission interval Tp. The interval Tr for acquiring the light receiving intensity by operating the A / D conversion unit 33 is set to a value sufficiently smaller than the average pulse interval so that the pulse wave fluctuation component can be regarded as constant. It shall be. The pulse interval corresponds to RRI (R-R Interval). The operation time (in other words, the sampling time) of the A / D conversion unit 33 may be appropriately designed.

FIG. 3 illustrates a case where light is emitted twice in one index value calculation process as an example. FIG. 4 is a flowchart showing the operation of the control unit 1 when the index value calculation process is executed when the number of times the LED 21 is made to emit light (hereinafter, the number of times of light emission) K is set to 2 times in one index value calculation process. Is.

The flowchart shown in FIG. 4 is repeatedly executed every sampling cycle Ts from the operation corresponding to the start of the biometric information identification process to the execution of a predetermined number of times required for analysis. Specifically, it is periodically executed from the step S204 to the step S207 of the biometric information identification process described later. The execution conditions for the index value calculation process may be appropriately designed, and are not limited to the above-described embodiments. When the execution subject of the step in the following description is omitted, the execution subject of the step is the control unit 1. Various data acquired or calculated in the index value calculation process shall be stored in the RAM 12 and used for other arithmetic processes.

First, in step S101, the light emission control unit F1 outputs an instruction to turn off the LED 21 to the light emitting module 2 (more specifically, the drive circuit 22), and shifts to the light emitting state. If the light is already off, the state may be continued. Then, the light receiving intensity acquisition unit F2 operates the A / D conversion unit 33, acquires data indicating the light intensity (hereinafter, light receiving intensity) received by the PD 31 from the A / D conversion unit 33, and takes step S102. Move to.

Hereinafter, the value of the light receiving intensity acquired in the step S101 will be referred to as L1 in order to distinguish it from the light receiving intensity acquired in the other steps. Regarding the light receiving intensity acquired in the other steps, L2 to L5 are introduced and described as variables indicating the specific values. Further, hereinafter, the light receiving intensity when the LED 21 is turned off is also described as the light receiving intensity when the LED 21 is turned off, and the light receiving intensity when the LED 21 is made to emit light is also described as the light emitting intensity.

The extinguishing intensity L1 represents the intensity of the disturbance light (that is, the disturbance light component) because it represents the intensity of the light received by the PD 31 when the user is not irradiated with the light from the LED 21. The ambient light is light received by the PD 31 even if the LED 21 is not emitted. The ambient light may include, for example, sunlight, illuminating light, and the like. Further, the extinguishing intensity L1 acquired in step S101 corresponds to the extinguishing intensity before the LED 21 is made to emit light in the next step S102. Therefore, the extinguishing intensity L1 corresponds to the pre-irradiation intensity (in other words, the pre-irradiation intensity) corresponding to the emission of the LED 21 in the next step S102. The pre-emission intensity is the light-receiving intensity in a state before the LED 21 emits light. The light-receiving intensity acquisition unit F2 that acquires the extinguishing intensity L1 in step S101 corresponds to the above-mentioned pre-emission intensity acquisition unit F22, that is, the pre-irradiation intensity acquisition unit according to claim.

In step S102, the light emission control unit F1 outputs a signal for causing the LED 21 to emit light to the drive circuit 22, and causes the LED to emit light for a predetermined light emission duration Tq. The light emission duration Tq may be appropriately designed based on the response speed and processing speed of the A / D conversion unit 33 so that the A / D conversion unit 33 can output the light receiving intensity when the LED 21 is emitting light. ..

Further, in step S102, the light receiving intensity acquisition unit F2 operates the A / D conversion unit 33 in parallel with the light emission of the LED 21, and acquires data indicating the light receiving intensity (hereinafter referred to as the light emitting intensity) L2 when the LED 21 emits light. Then, the process proceeds to step S103. The intensity L2 at the time of light emission corresponds to the intensity at the time of irradiation described in claim. The light emitting intensity L2 acquired in step S102 corresponds to the light emitting intensity corresponding to the first light emission of the LED 21 in one index value calculation process. The light receiving intensity acquisition unit F2 that acquires the light emission intensity L2 corresponds to the above-mentioned light emission intensity acquisition unit F21, that is, the irradiation intensity acquisition unit.

The intensity L2 at the time of light emission indicates a value in which a pulse wave fluctuation component is superimposed on a disturbance light component. Specifically, the emission intensity L2 is a component in which the light irradiated by the LED 21 is reflected and returned in the capillaries to the ambient light component, and the light irradiated by the LED 21 is reflected on the body surface (that is, the skin). It is a value to which the returned component (hereinafter referred to as the surface reflection component) is added. The surface reflection component is constant regardless of the state of the blood vessel when the wearing state of the pulse wave detection device 100 is stable, while the component reflected and returned in the capillaries is in the state of the blood vessel. Varies accordingly. The component that is reflected and returned in the capillaries corresponds to the pulse wave fluctuation component. It should be noted that the term "constant" here may include that the change over time is within a predetermined value. Since the body surface reflection component can be regarded as constant, it can be ignored in the phase of specifying biological information based on the waveform of the pulse wave.

In step S103, similarly to step S101, the light emission control unit F1 outputs an instruction to turn off the LED 21 to the drive circuit 22 to shift to the off state. Then, the light receiving intensity acquisition unit F2 operates the A / D conversion unit 33 to acquire the extinguishing intensity L3 and moves to step S104.

The extinguishing intensity L3 acquired in step S103 corresponds to the post-emission intensity (in other words, post-irradiation intensity) corresponding to the emission of the LED 21 in step S102. Therefore, the light receiving intensity acquisition unit F2 that acquires the extinguishing intensity L3 corresponds to the above-mentioned post-emission intensity acquisition unit F23, that is, the post-irradiation intensity acquisition unit.

Further, the extinguishing intensity L3 corresponds to the extinguishing intensity before the LED 21 is made to emit light in step S107. Therefore, the extinguishing intensity L3 corresponds to the intensity before emission corresponding to the emission of the LED 21 in step S107. The light receiving intensity acquisition unit F2 that acquires the extinguishing intensity L3 also corresponds to the above-mentioned pre-emission intensity acquisition unit F22, that is, the pre-irradiation intensity acquisition unit.

In step S104, the front difference intensity calculation unit F31 calculates a value Lb1 obtained by subtracting the extinguishing intensity L1 acquired immediately before acquiring the emission intensity L2 from the emission intensity L2, and moves to step S105. Hereinafter, the value obtained by subtracting the extinguishing intensity acquired immediately before acquiring the emission intensity from the emission intensity will be referred to as a pre-differential intensity. That is, step S104 is a step of calculating the pre-differential intensity Lb1 corresponding to the light emission of the LED 21 of step S102. The pre-differential intensity mainly indicates a pulse wave fluctuation component and a surface reflection component. However, the pre-difference intensity includes the time-dependent change of the disturbance light component derived from the time difference between the execution of step S101 and the execution of step S102 as an error.

In step S105, the post-differential intensity calculation unit F32 calculates a value La1 obtained by subtracting the extinguishing intensity L3 acquired immediately after acquiring the emission intensity L2 from the emission intensity L2, and moves to step S106. Hereinafter, the value obtained by subtracting the extinguishing intensity acquired immediately after acquiring the emission intensity from the emission intensity will be referred to as the post-differential intensity. That is, step S105 is a step of calculating the post-differential intensity La1 corresponding to the light emission of the LED 21 in step S102. The post-difference intensity mainly indicates a pulse wave fluctuation component and a surface reflection component. However, as in the case of the front difference intensity, the rear difference intensity also includes the time-dependent change of the disturbance light component derived from the time difference between the execution of step S102 and the execution of step S103 as an error.

In step S106, the pulse wave index value calculation unit F3 calculates the value obtained by adding the pre-difference intensity Lb1 calculated in step S104 and the post-difference intensity La1 calculated in step S105 as the sub-index value N1, and moves to step S107. As shown in FIG. 5, the sub-index value N1 calculated in this way is an error (+1) of the disturbance light component included in the pre-differential intensity when the change amount of the disturbance light component with time is constant. And the error (-1) of the ambient light component included in the post-differential intensity cancel each other out, and a value obtained by exactly doubling the biological component at the time of LED light emission is obtained. The biological component here is a combination of a pulse wave fluctuation component and a body surface reflection component. FIG. 5 illustrates a case where the biological component at the time of LED light emission is 100.

The sub-index value N1 obtained in this way is a parameter indicating the light receiving intensity of the biological component measured twice. Further, since the sub-index value N1 contains a pulse wave fluctuation component, it represents the state (volume / pressure) of the blood vessel at a certain time point, similarly to the pulse wave index. Therefore, the sub-index value N1 itself can also be used as the pulse wave index value M.

Returning to FIG. 4 again, the explanation of the sampler processing will be continued. The control unit 1 executes step S107 when the process in step S106 is completed. In step S107, similarly to step S102, the light emission control unit F1 outputs a signal for causing the LED 21 to emit light to the drive circuit 22 to emit light, and the light receiving intensity acquisition unit F2 operates the A / D conversion unit 33. The intensity L4 at the time of light emission is acquired, and the process proceeds to step S108. The emission intensity L4 acquired in step S107 corresponds to the emission intensity corresponding to the second emission in one index value calculation process.

In step S108, similarly to steps S101 and S103, the light emission control unit F1 outputs an instruction to turn off the LED 21 to the drive circuit 22 to shift to the off state. Then, the light receiving intensity acquisition unit F2 operates the A / D conversion unit 33, acquires the extinguishing intensity L5, and proceeds to step S109. The extinguishing intensity L5 corresponds to the intensity after light emission corresponding to the light emission of the LED 21 in step S107.

In step S109, the front difference intensity calculation unit F31 calculates the front difference intensity Lb2 corresponding to the light emission of the LED 21 in step S107. That is, the pre-differential intensity Lb2 is calculated by subtracting the extinguishing intensity L3 acquired immediately before acquiring the emission intensity L4 from the emission intensity L4. When the process in step S109 is completed, the process proceeds to step S110.

In step S110, the posterior difference intensity calculation unit F32 calculates the posterior difference intensity La2 corresponding to the light emission of the LED 21 in step S107. That is, the post-differential intensity La2 is calculated by subtracting the extinguishing intensity L5 acquired immediately after acquiring the emission intensity L4 from the emission intensity L4. When the processing in S110 is completed, the process proceeds to step S111.

In step S111, the pulse wave index value calculation unit F3 calculates the value obtained by adding the front difference intensity Lb2 calculated in S109 and the rear difference intensity La2 calculated in S110 as the sub-index value N2, and moves to S112. The sub-index value N1 calculated in step S106 is a sub-index value corresponding to the light emission of the LED 21 in step S102 (that is, the first light emission), and the sub-index value N1 calculated in S111 is in step S107. It is a sub-index value corresponding to the light emission of the LED 21 (that is, the second light emission). Hereinafter, the sub-index values N1 and N2 are not distinguished from each other, and when the concept corresponding to the sub-index values N1 and N2 is referred to, the sub-index values N are described. The pulse wave index value calculation unit F3 calculates the sub-index value N, which is the sum of the front difference intensity and the rear difference intensity, each time the LED 21 is made to emit light.

In step S112, the pulse wave index value calculation unit F3 calculates the value obtained by adding the sub-index value N1 calculated in step S106 and the sub-index value N2 calculated in step S111 as the pulse wave index value M, and ends this flow. do.

In the above, the operation of the control unit 1 when the number of light emission K in one index value calculation process is set to 2 has been described, but the number of light emission K is appropriately designed according to the type of biological information to be specified. Just do it. The number of light emission K may be one. When K = 1, the sub-index value N1 may be adopted as the pulse wave index value M as it is.

As the number of light emission K increases, as shown in FIG. 6, the level at which the pulse wave index value M changes increases, and the amplitude thereof also increases. The higher the transition level of the pulse wave index value M, the smaller the ratio of the disturbance light component to the pulse wave fluctuation component (that is, the S / N ratio). That is, the larger the number of light emission K is set, the more the disturbance light component as an error included in the pulse wave index value M can be suppressed, and the data obtained by arranging the pulse wave index values M in chronological order is the actual pulse wave. The data shows the characteristics (peak sharpness, etc.) of the waveform with higher accuracy. The broken line in FIG. 6 conceptually represents the transition level when the number of light emission K is set to 1, and the alternate long and short dash line conceptually represents the transition level when the number of light emission K is set to 2. The solid line conceptually represents the transition level when the number of light emission K is set to 3.

It should be noted that each time the number of light emission K in one index value calculation process is increased, the number of times the process corresponding to steps S107 to S111 is executed may be increased. Increasing the number of light emission K corresponds to increasing the number of additions of the sub-index value N. Further, increasing the number of times of light emission K corresponds to a level at which the pulse wave index value M changes, that is, an increase in the transition level of the pulse wave waveform formed by connecting the pulse wave index values M or an increase in amplitude. do.

The pulse wave index value M is the total value of the sub-index values N calculated in one index value calculation process. Each sub-index value N represents a pulse wave fluctuation component, and since the emission interval Tp is set to a value sufficiently smaller than the pulse interval, the pulse is the total value of the sub-index values N. The wave index value M also indicates a pulse wave fluctuation component at a certain time point.

In this embodiment, the number of sub-index values N calculated in one index value calculation process coincides with the number of light emission times K. Therefore, when the number of light emission K of one index value calculation process is four, the sub index value N is calculated four times, and the total value becomes the pulse wave index value. Since one sub-index value N is a value obtained by doubling the biological component at the time of LED light emission, the pulse wave index value M when the number of times of light emission K is 4 is equivalent to the value obtained by multiplying the biological component by 8. Signal strength (in other words, level).

The control unit 1 forms a signal sequence showing the waveform of the pulse wave shown in FIG. 3 by arranging the pulse wave index values M sequentially acquired by the above index value calculation process in chronological order.

<About biometric information identification processing>
Next, the biometric information identification process executed by the control unit 1 will be described. The biological information specifying process is a process of specifying a numerical value / state of a predetermined item indicating a user's state by analyzing a time change (that is, a pulse wave) of a pulse wave index value obtained by the index value calculation process.

Items that can be identified by the biological information specifying unit F8 from the waveform of the pulse wave (in other words, the type of biological information) may be appropriately designed. Here, as an example, it is assumed that the biological information specifying unit F8 is configured to be able to specify the pulse rate, the activity state of the autonomic nerve, the respiratory rate, the respiratory depth, the amount of change in the intrathoracic pressure, and the blood pressure. Of course, the biometric information specifying unit F8 does not have to be configured to be able to specify all of them, and may be configured to be able to specify only a part of them. In addition, items other than those described above may be identifiable.

The pulse rate (in other words, the heart rate) can be calculated based on the peak interval of the pulse wave (that is, RRI). For example, a value obtained by dividing 60 seconds by the average value or the median value of RRI per fixed time can be adopted as the pulse rate. The activity state of the autonomic nerve can be specified by the presence or absence of fluctuation of RRI. Specifically, it can be specified by frequency analysis of RRI time series data. The active state of the autonomic nerve includes whether the sympathetic nerve or the parasympathetic nerve is active (in other words, dominant). The degree of sympathetic nerve activity also serves as an indicator of whether the user is stressed or relaxed.

Respiratory rate is the respiratory rate per fixed time. The respiratory rate per fixed time can be specified by the number of peaks of the envelope of the pulse wave in the time zone. The peak spacing of the envelope of the pulse wave represents the rhythm of breathing. Therefore, the biological information specifying unit F8 can also specify the rhythm of pulse wave respiration. Respiratory depth can be determined based on the amplitude of the envelope of the pulse wave. The amount of change in intrathoracic pressure is represented by the difference between the primary and secondary envelopes of the pulse wave. Blood pressure can be specified from the distribution of feature points included in a waveform obtained by differentiating a pulse wave twice with respect (so-called acceleration pulse wave). The acceleration pulse wave is also academically referred to as a second-order differential pulse wave.

Items (hereinafter referred to as specific targets) specified by the control unit 1 (specifically, the biological information specifying unit F8) are configured to be selectable by the user via the operation unit 5. That is, the user can select a specific target item by operating the operation unit 5. Further, it is assumed that the control unit 1 of the present embodiment is configured so that a plurality of types of items can be set as specific targets by the user.

The biometric information specifying process is executed, for example, when a user operation instructing the operation unit 5 to start the biometric information specifying process is performed. The content of the user operation such as whether or not the user operation instructing the start of the biometric information specifying process has been performed is specified by the operation signal input from the operation unit 5. The biometric information specifying process may be automatically and repeatedly executed at a predetermined specific cycle Tx. In other words, the control unit 1 may include an operation mode (hereinafter referred to as a periodic diagnosis mode) that automatically executes the biometric information identification process in a predetermined specific cycle Tx.

FIG. 7 is a flowchart for explaining the biological information identification process. The operation of the control unit 1 in the biometric information identification process will be described with reference to the flowchart shown in FIG. 7. If the execution subject of the step in the following description is omitted, the execution subject of the step is the control unit 1. Various data acquired or calculated in the biological information identification process shall be stored in the RAM 12 and used for other arithmetic processes.

First, in step S201, the specific target setting unit F4 specifies the biometric information (in other words, an item) selected by the user as the specific target based on the operation signal input from the operation unit 5, and the specific target is the specific target. Is set to, and the process proceeds to step S202. In step S202, the setting change process is executed. The setting change process is a process of changing various parameters that determine the operation mode of the pulse wave detection device 100 to set values according to the items set for the specific target by the user operation. The setting change process will be described with reference to the flowchart shown in FIG.

First, in step S301 as the first step of the setting change process, whether or not the item designated as the specific target by the user needs to be highly analyzed (in other words, detected with high accuracy) the pulse wave. Is determined. The item that requires advanced analysis of the pulse wave corresponds to the item that the pulse wave index value M collected with relatively high accuracy and high resolution needs to be used as a population in order to specify the item. For example, the activity state of the autonomic nerve may correspond to an item requiring advanced analysis of pulse waves because it is necessary to identify the fluctuation of RRI with high accuracy. In addition, blood pressure is estimated using an index determined by the first-order derivative, the second-order derivative, or the like of the pulse wave. Therefore, blood pressure may also be an item that requires advanced analysis of pulse waves.

On the other hand, the pulse rate determined by RRI can be specified as long as the peak of the pulse wave can be detected. In addition, it is not necessary to specify the peak so strictly that the fluctuation of RRI can be detected. That is, the pulse rate can be specified by using the pulse wave index value M, which is expressed with a relatively low resolution and includes a certain amount of error.

Based on the above, here, as an example, the activity state of the autonomic nerve, the respiratory rate, the respiratory depth, the amount of change in the intrathoracic pressure, and the blood pressure are registered in advance as items that require advanced analysis of the pulse wave, and the pulse rate. Is set as an item that does not require advanced analysis. Items that require advanced analysis of pulse waves and items that do not require advanced analysis of pulse waves may be appropriately designed.

In the above setting, if any item requiring the altitude analysis of the pulse wave is not selected, it is determined that the altitude analysis of the pulse wave is unnecessary, and the process proceeds to step S302. Specifically, when only the pulse rate is set as the specific target, it is determined that the altitude analysis of the pulse wave is unnecessary, and the process proceeds to step S302. On the other hand, if at least one item other than the pulse rate, that is, an item requiring advanced analysis of the pulse wave is set as a specific target, it is determined that advanced analysis of the pulse wave is necessary, and step S305 is performed. Move.

In step S302, the A / D conversion setting changing unit F6 changes the setting of the A / D conversion unit 33 to a predetermined simple analysis setting. Specifically, each of the OSR and the number of bits used is set to a predetermined default value, and the process proceeds to step S303. The default value of OSR may be set to a value that provides a sampling rate necessary and sufficient for specifying the pulse rate. The default value of the number of bits used is, for example, 18 bits. When the process in step S302 is completed, the process proceeds to step S303. The state in which the OSR and the number of bits used are set to their respective default values corresponds to the simple analysis mode described in the claim.

In step S303, the target level setting unit F5 sets the target level of the pulse wave index value M to a predetermined first target level Lv1. The first target level Lv1 may be set so that, for example, the pulse wave index value M changes at a level necessary for specifying the pulse rate. For example, the first target level Lv1 may be set to 512. According to such an embodiment, the pulse wave can be analyzed with a resolution of 9 bits. When the process in step S303 is completed, step S304 is executed.

In step S304, the number of light emission K in one index value calculation process is set to a predetermined first default number K1. The first default number of times K1 is set so as to satisfy, for example, the following relational expression 1.

(K1-1) × N0 <Lv1 ≦ K1 × N0 ・ ・ ・ (Equation 1)
N0 in the above equation 1 is a design assumption value of the sub-index value N obtained by one LED light emission. According to the setting of the above formula 1, it is possible to obtain the required amplitude as the pulse wave index value M without causing the LED 21 to emit light more than necessary. In the present embodiment, as an example, it is assumed that the first default number K1 is set to 2, and the following description will be given.

The amount of light emitted from the LED 21 reflected by the blood vessels (in other words, the pulse wave fluctuation component) varies from person to person. Further, the light receiving intensity as a pulse wave fluctuation component may differ depending on the state in which the pulse wave detection device 100 is attached. Therefore, the sub-index value N obtained by one LED light emission varies depending on the physical characteristics of each user and the wearing state. The assumed value N0 of the sub-index value N used in the above equation 1 is a sub-index value observed when a person with an average physique uses the pulse wave detection device 100 in a wearing state based on the design specifications. It may indicate the average value of N. Further, the assumed value N0 of the sub-index value N is a representative value (for example, an average value, a median value, a mode value) statistically determined by using the actually measured value of the sub-index value N in people of various physiques as a population. May be good.

Further, in the present embodiment, as an example, the first default number of times K1 is set according to the above equation 1, but the present invention is not limited to this. The first default number K1 may be set by another rule. For example, a positive coefficient α may be introduced to determine K1 with reference to L1 × α instead of L1. α may be set to a value of about 0.5 to 1.5, for example, 0.8. When α = 1 is set, it is the same as Equation 1. When the process in step S304 is completed, this flow is terminated, and step S203 of the biometric information identification process shown in FIG. 7 is executed.

In step S305, the A / D conversion setting changing unit F6 changes the setting of the A / D conversion unit 33 to a predetermined advanced analysis setting. Specifically, each of the OSR and the number of bits used is set to a predetermined high level value, and the process proceeds to step S303. The high level value of OSR is at least higher than the default value. As described above, the accuracy of A / D conversion can be improved by increasing the OSR. The high level value of OSR may be set to twice the default value, for example. The high level value of OSR may be set to a sampling rate necessary and sufficient for specifying, for example, the activity state of the autonomic nerve and the blood pressure.

The high level value of the number of used bits may be higher than the default value (18 bits) of the number of used bits as long as the upper limit of the number of used bits (24 bits) is not exceeded. The high level value of the number of bits used is, for example, 20 bits. By increasing the number of bits used, the resolution of the light receiving intensity as an analog signal can be improved. When the process in step S305 is completed, the process proceeds to step S306. The state in which the OSR and the number of bits used are set to high level values corresponds to the advanced analysis mode described in the claim.

In step S306, the target level setting unit F5 sets the target level of the pulse wave index value M to a predetermined second target level Lv2. The second target level Lv2 may be set so that, for example, the pulse wave index value M changes with an amplitude necessary for specifying the activity state of the autonomic nerve and the blood pressure. The second target level Lv2 is set to a value larger than the first target level Lv1. For example, the second target level Lv2 may be set to 1024. According to such an embodiment, the pulse wave can be analyzed with a resolution of 10 bits. When the process in step S306 is completed, step S307 is executed.

In step S307, the number of light emission K in one index value calculation process is set to a predetermined second default number K2. The second default number of times K2 is set so as to satisfy, for example, the following relational expression 2. N0 in the following formula 2 is an assumed value of the sub-index value N as in the formula 1.

(K2-1) × N0 <Lv2 ≦ K2 × N0 ・ ・ ・ (Equation 2)
According to the setting of the above equation 2, it is possible to suppress the LED 21 from emitting light more than necessary while obtaining the amplitude required as the pulse wave index value M. Of course, the second default number K2 may be determined by other rules similar to the first default number K1. In the present embodiment, as an example, it is assumed that the second default number of times K2 is set to 4, and the following description will be given. When the process in step S307 is completed, this flow is terminated, and step S203 of the biometric information identification process shown in FIG. 7 is executed.

In the present embodiment, the sampling period Ts itself is constant, but the present invention is not limited to this. As another embodiment, the sampling period Ts may be changed depending on whether or not advanced analysis of the pulse wave is necessary. In that case, the sampling period Ts when the pulse wave altitude analysis is required may be set to a value shorter than the sampling period Ts when the pulse wave altitude analysis is not required.

In step S203, the light emitting number adjusting unit F7 performs the light emitting number adjusting process. The light emission number adjustment process is a process of adjusting the light emission number K in the index value calculation process so that the pulse wave index value M changes at a level corresponding to the target level. For example, when the pulse wave index value M changes below the target level set in step S202, the light emission frequency adjusting unit F7 emits light so that the pulse wave index value M1 changes at a level corresponding to the target level. Increase the number of times K. Further, when the pulse wave index value M is too large with respect to the target level set in step S202, the number of light emission K is reduced. Adjusting the light emission count K so that the pulse wave index value M changes at a level corresponding to the target level means that, according to another viewpoint, the light emission count K so that the pulse wave waveform provides the desired amplitude. Is equivalent to adjusting.

The light emission number adjustment unit F7 executes a process corresponding to each step as a light emission number adjustment process, for example, according to the flowchart shown in FIG. That is, as the first step S401, the light emission frequency adjusting unit F7 performs the index value calculation process a predetermined number of times in cooperation with the light emission control unit F1 and the like. The number of times of the index value calculation process to be executed on a trial basis (hereinafter referred to as the number of times of the test) may be set to the number of times that the pulse wave index value M for one heartbeat can be collected. For example, the number of tests may be a predetermined value assumed as the maximum value of RRI divided by the sampling period Ts. In step S401, in addition to the pulse wave index value M obtained as a result of the index value calculation process, the sub-index value N calculated in the process is also stored in the RAM 12. When the processing as step S401 is completed, step S402 is executed.

The pulse wave index value M collected as a result of the index value calculation process executed in step S401 is used for pulse wave analysis and the analysis when the number of light emission K is not changed as a result of this flow. It may be used to identify biometric information based on it. On the other hand, when the number of light emission K is changed as a result of this flow, the plurality of pulse wave index values M acquired in step S401 are processed so as not to be used for the analysis of the pulse wave and the identification of the biological information based on the analysis. It shall be (for example, discarded).

Next, in step S402, the light emission frequency adjusting unit F7 uses a plurality of pulse wave index values M collected in step S401 as a population, and is a representative value of the actually observed pulse wave index value M (hereinafter, pulse wave index representative value). ) Calculate Mx. As the representative value Mx of the pulse wave index, for example, an average value, a median value, a maximum value, a minimum value, or the like can be adopted. Here, as an example, the pulse wave index representative value Mx is the minimum value of the plurality of pulse wave index values M collected in step S401.

Further, in step S402, the light emission frequency adjusting unit F7 uses a plurality of sub-index values N collected in step S401 as a population, and sets a representative value (hereinafter, sub-index representative value) Nx of the actually observed sub-index values N. calculate. As the sub-index representative value Nx, for example, an average value, a median value, a maximum value, a minimum value, or the like can be adopted. Here, as an example, the sub-index representative value Nx is the minimum value of the plurality of sub-index values N collected in step S401. When the process in step S402 is completed, the process proceeds to step S403.

In step S403, it is determined whether or not the pulse wave index representative value Mx calculated (in other words, determined) in step S402 is below the target level. If the pulse wave index representative value Mx is below the target level, step S404 is executed. On the other hand, if the pulse wave index representative value Mx is not below the target level, step S405 is executed.

In step S404, the number of light emission K in the index value calculation process is increased by one. For example, as shown in FIG. 10, when the target level is set to the first target level Lv1 and the number of light emission K is set to the first default number K1 = 2, the pulse wave index representative value Mx is set. If it is below the first target level Lv1, the number of light emission K is increased by 1 to a total of 3 times.

According to such a configuration, the sub-index value N3 associated with the third LED light emission is added, so that the pulse wave index value M becomes large and exceeds the first target level Lv1. If the representative value of the pulse wave index value M does not exceed the first target level Lv1 by one increase, until the representative value of the pulse wave index value M exceeds the first target level Lv1. The number of light emission K may be increased once.

Further, it is not necessary to increase the number of light emission times K once. For example, the increase number kp may be calculated based on the shortage ΔM of the pulse wave index representative value Mx with respect to the target level and the sub-index representative value Nx. Specifically, as shown in the following equations 3A and 3B, an integer obtained by dividing the shortage ΔM by the sub-index representative value Nx and rounding up may be set as the number of increases kp. Equation 3A is an equation applied when ΔM / Nx is an integer, that is, when the shortage ΔM is divisible by the sub-index representative value Nx. Equation 3B is an equation applied when the shortfall ΔM is not divisible by the sub-index representative value Nx.

kp = ΔM / Nx ・ ・ ・ (Equation 3A)
kp = [ΔM / Nx] +1 ... (Equation 3B)
In addition, "[]" in the formula 3B is a Gaussian symbol. “[ΔM / Nx]” in Equation 3B indicates the largest integer that does not exceed the value obtained by dividing ΔM by Nx. When the increase number kp is determined using the formulas 3A and 3B, as shown in FIG. 11, the value obtained by adding the increase number kp to the default number set in step S202 is used as the final light emission number K. Adopt as. It should be noted that such an embodiment corresponds to an embodiment in which an appropriate number of light emissions in one index value calculation process is determined based on a sub-index representative value Nx having a plurality of sub-index values N as a population and a target level. do. When the process in step S404 is completed, this flow is terminated and step S204 of the biometric information identification process shown in FIG. 7 is executed.

In step S405, it is determined whether or not the pulse wave index representative value Mx is too large with respect to the target level. For example, when the value obtained by subtracting the target level from the pulse wave index representative value Mx is equal to or greater than the sub-index representative value Nx, it is determined that the pulse wave index representative value Mx is too large with respect to the target level. Another point of view is that the pulse wave index representative value Mx is too large for the target level. Corresponds to the case where exceeds the target level.

If the pulse wave index representative value Mx is too large for the target level, step S406 is executed. On the other hand, when the pulse wave index representative value Mx is not too large with respect to the target level, that is, when the difference between the pulse wave index representative value Mx and the target level is the sub-index representative value Nx, step S407 is performed. Execute.

In step S406, the number of light emission K is reduced by one. For example, as shown in FIG. 12, when the target level is set to the second target level Lv2 and the number of light emission K is set to the second default number K2 = 4, the representative value of the pulse wave index value M. However, when the sub-index value N or more is larger than the second target level Lv2, the number of light emission K is reduced by 1 to a total of 3 times. According to such a configuration, it is possible to suppress the light emission of unnecessary LEDs, and it is possible to suppress power consumption. In addition, the calculation load of the control unit 1 can be reduced.

When the process in step S406 is completed, this flow is terminated and step S204 of the biometric information identification process shown in FIG. 7 is executed. In step S407, the default number of light emission set in step S202 is maintained as it is as the number of light emission K, and this flow ends. Then, step S204 of the biometric information identification process shown in FIG. 7 is executed. That is, in the processing route in which steps S403 and S405 are negatively determined and the process proceeds to step S407, the number of light emission times K is not changed.

In step S204, the collection of the pulse wave index value M is started. That is, the sampling process starts to be executed. From this step S204 to the execution of S207 described later, the index value calculation process is performed in a predetermined sampling cycle Ts. The plurality of pulse wave index values M obtained as a result of the sampling process are sorted in the order of acquisition time and stored in the RAM 12 or the like.

In step S205, is it possible to specify the numerical value / state of the biometric information (in other words, the specific target item) designated by the user based on the plurality of pulse wave index values M stored in the RAM 12. Judge whether or not. According to another viewpoint, the determination process in step S205 determines whether or not the pulse wave index value M of the number required for specifying the numerical value / state of the specific target item (hereinafter referred to as the number required for analysis) can be collected. Corresponds to judgment. If the pulse wave index value M required for analysis has not been collected yet, the sampling process is continued (step S206), and step S205 is executed again after a certain period of time has elapsed. Then, when the pulse wave index value M required for analysis can be collected, the process proceeds to step S207.

In step S207, the sampling process is stopped and the process proceeds to step S208. In step S208, the biological information specifying unit F8 specifies the value / state of the specific target item based on the time-series data of the pulse wave index value M collected in the above processing. The method for specifying each of the various biometric information is as described above. When the process in step S208 is completed, step S209 is executed.

In step S209, the presentation processing unit F9 displays the numerical value / state for each biometric information specified in step S208 on the display unit 6 and ends this flow. The data indicating the numerical value / state for each biometric information specified in step S208 may be transmitted to the external device via the wireless communication module 7. The external device here may be a mobile terminal carried by a user such as a smartphone, or may be a center or the like.

The light emission count adjusting unit F7 of the present embodiment adjusts the light emission count K by performing the index value calculation process a plurality of trial times separately from the sampling process after step S204. Not limited to. The number of light emission K may be changed during the sampling process. However, if the number of light emission K is changed during the sampling process, the pulse wave index value M collected before that should not be used for pulse wave analysis and identification of biological information based on the analysis. It shall be processed (for example, discarded) or used with an offset so that the transition level of the pulse wave index value M matches.

<Effect of embodiment>
Next, the effect of this embodiment will be described by introducing a comparative configuration. As shown in FIG. 13, the comparative configuration here means that the light receiving intensities (that is, the intensities at the time of light emission) Lp1, Lp3, Lp5 when the LED 21 is made to emit light and the LED 21 are in the light emitting state in one index value calculation process. The total value of the differences between the light receiving intensity (that is, the intensity when the light is turned off) Lp2, Lp4, and Lp6 after switching from the light-off state to the light-off state is adopted as the pulse wave index value. In the figure, as an example, when one set is set from the emission of the LED 21 to the extinguishing of the LED 21, the total value of the difference between the intensity at the time of emission and the intensity at the time of extinguishing for four sets is adopted as the pulse wave index value. There is. For convenience, the difference value between the intensity at the time of light emission and the intensity at the time of extinguishing in one set is referred to as a sub-index value in the comparison configuration. The number of sets in one index value calculation process may be designed so that the pulse wave index value changes at a desired level.

In such a configuration, when the intensity of the disturbance light increases with time as shown in FIG. 14, the amount of change in the disturbance component due to the time difference ΔT of the detection timing of the received light intensity is included in the sub-index value as it is as an error. Is done. Specifically, in the example shown in FIG. 14, the change amount “1” of the disturbance component due to the time difference ΔT of the detection timing remains in the sub-index value as an error.

Further, in the comparative configuration, if the number of sets (in other words, the number of light emission) in one index value calculation process is increased so that the waveform of the pulse wave provides the desired amplitude, errors are accumulated according to the number of sets. .. For example, when the error per set is 1, the pulse wave index value, which is the total value of the sub-index values for 4 sets, includes an error of 1 × 4 = 4.

On the other hand, in the configuration of the present embodiment, two values (specifically, the front difference intensity and the back difference intensity) obtained by subtracting the intensity at the time of turning off the light immediately before and immediately after the LED 21 is emitted from the intensity at the time of irradiation are added. This generates one sub-index value N. The intensity at the time of extinguishing immediately before the LED 21 is made to emit light is the light receiving intensity acquired from the time when the LED 21 was made to emit light last time to the time when the LED 21 is made to emit light this time. According to another viewpoint, the intensity at the time of turning off the light immediately before the LED 21 emits light is the light receiving intensity at an arbitrary time point within the past and the duration of turning off the light from the time when the LED 21 starts to emit light (hereinafter, the time when the light emission starts). Further, the intensity at the time of extinguishing immediately after the LED 21 is changed from the light emitting state to the extinguished state is the light receiving intensity acquired from the time when the LED 21 is emitted this time to the next time when the LED 21 is emitted. The intensity at the time of extinguishing immediately after the LED 21 is changed from the light emitting state to the extinguished state is, according to another viewpoint, the light receiving intensity at an arbitrary time point from the time when the LED 21 is turned off until the elapse of the extinguishing duration.

According to such a calculation mode of the sub-index value N, as described above with reference to FIG. 5, when the amount of change of the disturbance light component with time is constant, the error of the disturbance light component included in the pre-differential intensity And the error of the disturbance light component included in the post-differential intensity cancels out, and a value obtained by exactly doubling the biological component (for example, 100) at the time of LED light emission in S102 is obtained. That is, it is possible to suppress that the error due to the change amount of the disturbance light component with time is included in the sub-index value N.

Therefore, it is possible to suppress that the pulse wave index value M itself, which is formed by accumulating the sub-index values N, includes an error due to the amount of change of the disturbance light component over time. As a result, the pulse wave waveform indicated by the time-series data of the pulse wave index value can be made closer to the actual pulse wave waveform. That is, according to the above configuration, the pulse wave can be detected more accurately.

-According to the configuration of the present embodiment, by causing the LED 21 to emit light twice, it is possible to obtain a pulse wave index value having the same magnitude as that of four sets in the comparative configuration. That is, the number of light emission K of the LED 21 required to obtain the pulse wave index value having the same amplitude as the comparative configuration can be reduced by half. As a matter of course, the smaller the number of times of light emission K, the lower the power consumption. That is, according to the configuration of the present embodiment, the power consumption can be suppressed as compared with the comparative configuration.

-In the present embodiment, the transition level of the pulse wave index value M is adjusted by adjusting the number of light emission K. As another configuration for adjusting the transition level of the pulse wave index value M, a configuration in which the emission intensity of the LED 21 itself is adjusted by controlling the current flowing through the LED 21 (hereinafter, assumed configuration) can be considered. However, simply doubling the emission intensity does not necessarily mean that the emission intensity is doubled. This is because the amount of reflected light received by the PD 31 varies depending on the skin color, the lens distance, the wearing state, and the like.

That is, since the correspondence between the emission intensity and the light reception intensity is uncertain, in the assumed configuration, it is possible to double the transition level of the desired pulse wave index value M even if the emission intensity is doubled. Not exclusively. Furthermore, in the assumed configuration, it is expected that as current control for shifting the transition level of the pulse wave index value M to a desired level, processing such as decreasing if the emission intensity is too high and increasing if it is too low is expected to be repeatedly executed. Will be done. Further, in the assumed configuration, a circuit module that controls current and power supply to the circuit module are required.

On the other hand, according to the configuration of the present embodiment, in order to adjust the transition level of the pulse wave index value M by increasing or decreasing the number of light emission times K, it is relative to set the transition level of the pulse wave index value M to a desired level. Easy to use. In particular, since the magnitude of the sub-index value N derived from each light emission is determined based on the measured value of the experimental index value calculation process, the correspondence between the number of light emission and the pulse wave index value is clear. .. In view of such facts, it can be said that the certainty and accuracy when setting the transition level of the pulse wave index value M to a desired level in the present embodiment is higher than the assumed configuration.

In addition, it is possible to suppress the time required for control for shifting the transition level of the pulse wave index value M to a desired level. Further, in the present embodiment, since the light emission intensity of the LED 21 can be set to a constant value, it is not necessary to supply a circuit module for performing current control required in the assumed configuration or power supply to the circuit module. Therefore, the component cost and power consumption can be suppressed as compared with the assumed configuration.

Further, as described above, there are individual differences in the amount of light reflected by the blood vessels emitted from the LED 21. On the other hand, according to the configuration of the present embodiment, the transition level of the pulse wave index value M can be adjusted by adjusting the number of light emission K. That is, it is possible to absorb (in other words, eliminate) individual differences in the amount of light reflected by the LED 21 by a relatively simple process such as increasing or decreasing the number of times of light emission K.

-In the present embodiment, when the altitude analysis of the pulse wave is required, the amplitude of the pulse wave is relatively increased by setting the number of emission times K to a relatively large value, while the altitude analysis of the pulse wave is performed. If it is not necessary, set the number of light emission K to a relatively small value. Since the number of light emission K is dynamically controlled as needed in this way, the power consumption can be further reduced.

-In the present embodiment, when advanced analysis of the pulse wave is not necessary, the performance of the A / D conversion unit 33 is reduced, such as a decrease in OSR and a decrease in the number of bits used, so that the value is set to a small value. , Power consumption can be further reduced.

When the pulse wave detection device 100 is operated in the periodic diagnosis mode, that is, when the biometric information identification process is periodically executed at a predetermined specific cycle Tx, the biometric information set as the specific target is periodically executed. Be identified. For example, the pulse rate, blood pressure, autonomic nerve activity state, etc. are periodically specified. Such a routine diagnostic mode can be used, for example, to inspect and monitor inpatients in hospitals. It can also be used for watching over elderly people, people requiring long-term care, drivers, etc. and managing their physical condition. In particular, it is suitable for managing the physical condition of a person who drives a long distance or a long time, such as a driver of a transportation vehicle or a travel bus. Of course, it can also be applied to other people. It should be noted that the above is an example of an embodiment in which a human is an observation target, but the present invention is not limited to this. It may be used for animals other than humans.

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications described below are also included in the technical scope of the present disclosure, and other than the following. Can be changed and implemented within the range that does not deviate from the gist.

The members having the same functions as those described in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted. Further, when only a part of the configuration is referred to, the configuration of the embodiment described above can be applied to the other parts.

[Modification 1]
In the above-described embodiment, one sub is added by adding two values (specifically, the front difference intensity and the rear difference intensity) obtained by subtracting the intensity at the time of turning off the light immediately before and immediately after the LED 21 is emitted from the intensity at the time of irradiation. The aspect of generating the index value N is disclosed. However, the extinguishing intensity subtracted from the irradiation intensity in calculating the sub-index value N does not have to be the extinguishing intensity immediately before and immediately after the LED 21 is made to emit light.

For example, as shown in FIG. 15, in a configuration in which the LED 21 is emitted three times in one index value calculation process, the intensity L1 at the time of extinguishing obtained before the first emission is obtained from the intensity L4 at the time of emission corresponding to the second emission. The front difference intensity is calculated by subtracting, and the back difference intensity is calculated by subtracting the extinguishing intensity L7 acquired after the third light emission from the light emission intensity L4 corresponding to the second light emission, and adding them. By combining them, one sub-index value N4 may be generated.

Note that L6 in FIG. 15 indicates the intensity at the time of light emission corresponding to the third light emission, and N3 is a sub-index value N corresponding to the light emission of the third LED 21. The sub-index value N3 corresponding to the light emission of the third LED 21 is the pre-differential intensity obtained by subtracting the light emission intensity L5 immediately before the third light emission from the light emission intensity L6 and the light emission intensity L6 immediately after the third light emission. After subtracting the extinguishing intensity L7, the difference intensity is added.

According to such a control mode, a total of four sub-index values N can be calculated by three times of light emission. That is, it is possible to obtain a pulse wave index value M that provides a transition level equivalent to that in the case where the number of light emission K is set to 4 in the configuration of the embodiment.

Further, in the above-described embodiment, it is necessary to set the number of light emission K to 4 in order to calculate the pulse wave index value M having the same size as the total value of the sub-index values N for 8 sets in the comparative configuration. .. On the other hand, if the configuration of this modification described with reference to FIG. 15 is applied, a pulse wave index value M having a size equivalent to the total value of the sub-index values for eight sets in the comparative configuration is obtained by three times of light emission. be able to. That is, when the pulse wave index value M having the same size as the total value of the sub-index values for eight sets in the comparative configuration is to be obtained by one index value calculation process, the configuration of the modification 1 is adopted. Therefore, the number of light emission can be suppressed as compared with the embodiment. As a result, power consumption can be further reduced. In addition, the time required for one index value calculation process can be shortened.

In the above, the operation of the control unit 1 when the idea of the present modification 1 is applied when the LED 21 is made to emit light three times in one index value calculation process has been described, but the number of times of light emission K is 4 or more. Can be applied in the same way.

[Modification 2]
The control unit 1 is configured to be able to selectively implement both the method for calculating the pulse wave index value in the above-described embodiment and the method for calculating the pulse wave index value by the comparative configuration, depending on the external environment and the like. It may be configured to use those calculation methods properly. For convenience, the operation mode for calculating the pulse wave index value M by the method disclosed in the embodiment is referred to as a first mode, and the operation mode for calculating the pulse wave index value M by the disclosed method as a comparative configuration is referred to as a second mode. ..

For example, the control unit 1 operates in the first mode when an item that needs to use the high frequency component of the pulse wave is selected as a specific target item, while the item that needs to use the high frequency component of the pulse wave is If it is not selected, it operates in the second mode.

As a result of evaluating the noise suppression effect of the first mode and the second mode by various tests, the inventors can suppress the noise superimposed on the high frequency component of the pulse wave in the first mode than in the second mode, while relative. It was found that the noise suppression effect may be higher in the second mode than in the first mode in a particularly low frequency band. Therefore, by properly using the first mode and the second mode according to the item set as the specific target item, the numerical value / state of the specific target item can be specified more accurately.

[Modification 3]
The target level setting unit F5 sets a target when the value of the intensity when the light is turned off is equal to or higher than a predetermined threshold value (hereinafter, the threshold value under sunlight) indicating that the pulse wave detection device 100 is used in an environment exposed to sunlight. The level may be set to a higher level than when the intensity when the light is turned off is less than the threshold value under sunlight. For example, when the intensity when the light is turned off is less than the threshold value under sunlight, the target level setting unit F5 sets the default level according to whether or not altitude analysis is required. On the other hand, when the intensity when the light is turned off is equal to or higher than the threshold value under sunlight, the value is set by multiplying the default level by 1.5. The magnification of the target level applied when the intensity when the light is turned off is equal to or higher than the threshold value under sunlight may be larger than 1, for example, 1.2 times or 2.0 times. .. Further, the final target level may be set to a relatively high level by adding a predetermined value to the default level instead of multiplying by a predetermined coefficient.

According to the configuration of this modification 3, it is possible to suppress a decrease in the detection accuracy of the pulse wave in an environment exposed to sunlight. Specifically, it is as follows. First of all, as a premise, sunlight is stronger than the light of lighting generally used indoors. Therefore, in an environment exposed to sunlight, the ambient light component tends to be larger than when it is used indoors or the like. In response to such a problem, in the configuration of the present modification 3, when the intensity when the light is turned off is equal to or higher than the threshold value under sunlight, the target level is set to a relatively high level. The number of light emission K is also increased, and the amplitude of the pulse wave index value M over time can be increased. If the amplitude of the pulse wave index value M with time is increased, the S / N ratio is lowered, so that the influence of sunlight on the detection result can be suppressed.

[Modification 4]
When the value of the intensity when the light is turned off of the A / D conversion setting changing unit F6 is equal to or higher than a predetermined threshold value (hereinafter referred to as the threshold value under sunlight) indicating that the pulse wave detection device 100 is used in an environment exposed to sunlight. , The sampling time may be set to a value shorter than the case where the intensity when the light is turned off is less than the threshold value under sunlight. As a premise, the A / D conversion unit 33 is configured so that the value of the sampling time can be changed. The sampling time is the time for storing the input analog voltage to be sampled, and corresponds to the time for operating the A / D conversion unit 33 in one A / D conversion process.

For example, the A / D conversion setting change unit F6 sets a predetermined value (that is, a default value) when the intensity at the time of extinguishing is less than the threshold value under sunlight. On the other hand, when the intensity when the light is turned off is equal to or higher than the threshold value under sunlight, a value shorter than the default value, for example, a value 0.5 times is set. The magnification may be smaller than 1, for example, 0.8 times.

According to the configuration of the modification 4, when the intensity at the time of extinguishing is equal to or higher than the threshold value under sunlight, the sampling time is set to a relatively short value, so that the performance of removing ambient light is improved. As a result, it is possible to suppress a decrease in the detection accuracy of the pulse wave in an environment exposed to sunlight, as in the modified example 3. When the intensity at the time of extinguishing is less than the threshold value under sunlight, the sampling time is set to a relatively long value, so that the accumulated voltage at one time can be increased.

[Modification 5]
The target level setting unit F5 sets the target level when the output value of the acceleration sensor 4 is equal to or higher than a predetermined body movement threshold indicating that the user is moving, and the output value of the acceleration sensor is less than the body movement threshold value. It may be set to a higher level than in some cases.

When the pulse wave detection device 100 is configured as a wearable device and the user is moving, the contact state between the pulse wave detection device 100 and the user's body may change depending on the movement of the user. As a matter of course, if the contact state fluctuates, the probability of mixing ambient light changes, so that the detection accuracy is expected to deteriorate. For such a problem, according to the configuration of the present modification 5, when the output value of the acceleration sensor 4 is equal to or higher than the body movement threshold value, that is, when the value indicates that the user is moving. Since the target level is set to a relatively high level, the number of light emission K increases with the increase of the target level, and the amplitude of the pulse wave index value M with time can be increased. If the amplitude of the pulse wave index value M with time is increased, the S / N ratio is lowered, so that the influence of the disturbance light on the detection result can be suppressed.

[Modification 6]
In the above-described embodiment, the embodiment in which the post-emission intensity corresponding to the jth emission (j is a natural number) is also used as the pre-emission intensity corresponding to the j + 1th emission in the pulse wave index value calculation process is disclosed. For example, we have disclosed an embodiment in which the extinguishing intensity L3 as the intensity after light emission corresponding to the first light emission is also used as the intensity before light emission corresponding to the second light emission. However, the operation mode of the light receiving intensity acquisition unit F2 is not limited to this.

As shown in FIG. 16, for example, in addition to the extinguishing intensity L3 as the intensity after light emission corresponding to the first light emission, the intensity L8 at extinguishing as the intensity before light emission corresponding to the second light emission may be acquired. .. L9 shown in FIG. 16 represents the intensity at the time of light emission corresponding to the second light emission, and L10 represents the intensity at the time of extinguishing as the intensity after light emission corresponding to the second light emission.

100 Pulse wave detector, 1 control unit, 2 light emitting module (light emitting unit), 3 light receiving module (light receiving unit), 4 accelerometer, F1 light emitting control unit, F2 light receiving intensity acquisition unit, F3 pulse wave index value calculation unit, F4 Specific target setting unit, F5 target level setting unit, F6 A / D conversion setting change unit (conversion unit setting change unit), F7 light emission frequency adjustment unit, F8 biometric information identification unit, F9 presentation processing unit

Claims (8)

The index value calculation process for calculating the pulse wave index value indicating the state of the blood vessel of the living body by irradiating the living body as an observation target is sequentially executed at a predetermined sampling cycle, and the time change of the pulse wave index value is performed. It is a pulse wave detection device that detects the pulse wave of the living body based on the above.
A light emitting control unit (F1) that controls the operation of the light emitting unit that irradiates light and causes the light emitting unit to emit light a predetermined number of times in one index value calculation process.
From the light receiving unit (3) that outputs the light receiving intensity which is the intensity of the light arriving from the direction in which the light emitting unit irradiates the light, the light receiving intensity when the light emitting control unit irradiates the light emitting unit with light is obtained. , The irradiation intensity acquisition unit (F21) acquired as the irradiation intensity, and
The pre-irradiation intensity acquisition unit that acquires the light-receiving intensity when the light-emitting unit is not irradiating light, and the light-receiving intensity before the light-emitting control unit irradiates the light-emitting unit with light, as the pre-irradiation intensity. (F22) and
The post-irradiation intensity acquisition, which is the light receiving intensity when the light emitting unit is not irradiating light, and the light receiving intensity after the light emitting control unit irradiates the light emitting unit with light is acquired as the post-irradiation intensity. Part (F23) and
Each time the light emitting control unit irradiates the light emitting unit with light, the pre-difference intensity is calculated by subtracting the pre-irradiation intensity corresponding to the irradiation from the irradiation intensity corresponding to the irradiation. Strength calculation unit (F31) and
Each time the light emission control unit irradiates the light emitting unit with light, the post-difference intensity is calculated by subtracting the post-irradiation intensity corresponding to the irradiation from the irradiation intensity corresponding to the irradiation. Strength calculation unit (F32) and
The pre-difference intensity calculated by the pre-difference intensity calculation unit and the post-difference calculated by the post-difference intensity calculation unit each time the light emission control unit irradiates the light emitting unit with light in one index value calculation process. It is provided with an index value calculation unit (F3) that calculates a value obtained by adding the intensities as the pulse wave index value .
The index value calculation unit
A light emitting number adjusting unit (F7) for adjusting the number of light emission, which is the number of times the light emitting unit is made to emit light in one index value calculation process, is provided so that the pulse wave index value changes at a predetermined target level. A characteristic pulse wave detector. The pulse wave detection device according to claim 1 .
The index value calculation unit irradiates the light emitting unit with light as a sub-index value which is a total value of the front difference intensity and the rear difference intensity obtained one by one by irradiating the light emitting unit with light once. It is calculated every time it is made.
The light emission frequency adjusting unit calculates a representative value having a plurality of the sub-index values as a population, and the pulse wave index value changes at the target level based on the representative value and the target level. A pulse wave detection device, characterized in that an appropriate number of times of light emission is determined. The pulse wave detection device according to claim 1 or 2 .
A biological information identification unit (F8) configured to be able to identify a plurality of types of biological information indicating the state of the living body based on time-series data in which the pulse wave index values are arranged in chronological order.
Among the plurality of types of the biometric information, the specific target setting unit (F4) that sets the biometric information to be specified by the biometric information specific unit based on the user operation, and the specific target setting unit (F4).
A pulse wave detection device including a target level setting unit (F5) that sets the target level to a value corresponding to the type of biometric information set as a specific target by the specific target setting unit. .. The pulse wave detection device according to claim 3 .
At least one of the plurality of types of the biometric information is registered in advance as the biometric information that requires advanced analysis of the pulse wave.
The target level setting unit is
When the biometric information of the type set in the biometric information that requires advanced analysis of pulse waves is not set as the specific target, the target level is set to a predetermined first target level, while the target level is set to a predetermined first target level.
When the biometric information of the type set as the biometric information that requires advanced analysis of the pulse wave is set as the specific target, the target level is set to a predetermined second target level higher than the first target level. A pulse wave detector characterized by setting to a target level. The pulse wave detection device according to claim 3 or 4 .
The light receiving unit includes an analog digital conversion unit (33) that converts an analog signal indicating the light receiving intensity output by the light receiving element into a digital signal and outputs the digital signal.
The analog-to-digital conversion unit is configured to be able to change at least one of the sampling rate and the resolution when converting an analog signal into a digital signal.
A conversion unit setting change unit (F6) for adjusting the value of a parameter configured to be able to change the set value among the sampling rate and the resolution of the analog-to-digital conversion unit is provided.
The conversion unit setting change unit is
When the biometric information set in the biometric information that requires advanced analysis of the pulse wave is not set as the specific target, the analog-to-digital converter is operated in a predetermined simple analysis mode. While setting the value of the parameter
When the biometric information set in the biometric information that requires advanced analysis of the pulse wave is set as the specific target, the analog-to-digital conversion unit is operated in a predetermined advanced analysis mode. A pulse wave detector characterized by setting parameter values. The pulse wave detection device according to claim 5 .
The analog-to-digital conversion unit is configured so that the sampling time can be changed.
In the conversion unit setting changing unit, the light receiving intensity when the light emitting unit is not irradiated is equal to or higher than a predetermined threshold value under sunlight indicating that the intensity at the time of extinguishing is used in an environment exposed to sunlight. If this is the case, the pulse wave detection device is characterized in that the sampling time is set to a value shorter than that when the intensity when the light is turned off is less than the threshold value under sunlight. The pulse wave detection device according to any one of claims 3 to 6 .
In the target level setting unit, the light receiving intensity when the light emitting unit is not irradiating light is equal to or higher than a predetermined threshold under sunlight indicating that the intensity at the time of extinguishing is used in an environment exposed to sunlight. In some cases, the pulse wave detection device is characterized in that the target level is set to a higher level than when the intensity when the light is turned off is less than the threshold value under sunlight. The pulse wave detection device according to any one of claims 3 to 7 is attached to a predetermined part of the living body and used.
Equipped with an acceleration sensor (4) that detects acceleration,
When the output value of the acceleration sensor is equal to or higher than a predetermined body movement threshold indicating that the living body is moving, the target level setting unit sets the target level and the output value of the acceleration sensor is the body. A pulse wave detection device characterized in that it is set to a higher level than when it is below the dynamic threshold.

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