JP7541469B2 - Mobile terminal, blood pressure measurement method, and blood pressure measurement program - Google Patents

Description

The present invention relates to a mobile terminal, a blood pressure measurement method, and a blood pressure measurement program.

In recent years, electronic devices such as mobile terminals equipped with healthcare functions that measure the user's blood pressure, heart rate, etc. have been developed.

For example, Patent Document 1 proposes a bioinformation analyzer equipped with two pulse wave sensors positioned so that pulse wave signals can be detected from two points at different distances from the heart. Patent Document 2 proposes a contact-type blood pressure measurement device that improves the accuracy of blood pressure measurement from a finger by displaying on a display guidelines indicating the pressure to be applied to the sensor during blood pressure measurement. Patent Document 3 proposes a bioinformation measurement device that estimates the contact area between a sensor unit and a subject based on information detected by a fingerprint sensor, and acquires bioinformation based on the estimated contact area and the pulse wave signal detected by the sensor unit.

JP 2017-018587 A JP 2018-102906 A JP 2020-018837 A

Blood pressure is one of the important vital sign information that indicates the circulatory dynamics of the body, so measuring blood pressure is useful for understanding health conditions. There are two types of blood pressure measurement methods in practical use: non-invasive and invasive. As a non-invasive blood pressure measurement method, many electronic blood pressure monitors on the market use the oscillometric method, which applies pressure to the upper arm or wrist with a cuff and detects the vibration of the cuff caused by the pulse wave.

As an oscillometric method, there is a decompression measurement method in which a cuff attached to the upper arm or wrist is quickly inflated to a specified pressure, and then gradually decompressed while detecting the vibration of the cuff caused by the pulse wave, as well as a linear pressurization measurement method (also called iNIBP (registered trademark)) in which the living body is gradually pressurized while detecting the pulse wave during pressurization, and pressurization of the living body is stopped once the systolic blood pressure has been measured. With the latter linear pressurization measurement method, pressurization of the living body can be stopped once the systolic blood pressure has been measured, so there is no need to pressurize the living body to a uniform pressure as with the decompression measurement method. Therefore, blood pressure can be measured in a shorter time than with the decompression measurement method, in which the living body is pressurized to a specified pressure.

The oscillometric method thus applies pressure to a living body and measures blood pressure from the pulse wave at the pressurized part, so it is possible, for example, to have the subject pressurize the photoelectric pulse wave sensor and pressure sensor with their fingertip, and measure blood pressure values from the fingertip pulse wave. Therefore, for example, if a photoelectric pulse wave sensor and pressure sensor are provided in an electronic device such as a smartphone that is carried around daily, the user of the electronic device can easily measure blood pressure.

However, with the oscillometric method, the applied pressure of the living body must follow a specified pressure pattern. However, it is not easy to adjust the pressure of the fingertip so that it follows a specified pressure pattern by increasing or decreasing the force of the fingertip.

One aspect of the disclosed technology is to provide a mobile device, a blood pressure measurement method, and a blood pressure measurement program that enable pressure to be easily applied with the fingertip in accordance with a pressure pattern specified for blood pressure measurement.

One aspect of the disclosed technology is exemplified by a mobile terminal as follows. This mobile terminal includes a first sensor provided on the back surface of a plate-shaped housing and pressed by a first finger, a second sensor that detects the pressure applied to the first sensor, a touch screen provided on the front surface of the housing, and a processing unit that measures blood pressure based on biological information acquired from the first finger by the first sensor. The processing unit displays a guide image on the touch screen that guides the position of the second finger that pinches the housing together with the first finger, moves the guide image in a predetermined direction, acquires the pressure detected by the second sensor, and measures blood pressure based on the biological information acquired from the first sensor when the relationship between the position of the guide image and the pressure detected by the second sensor satisfies a predetermined pressure pattern.

The disclosed technology makes it possible to easily apply pressure with the fingertips in a specific pattern specified in blood pressure measurement.

FIG. 1 is a diagram illustrating an example of an external appearance of a smartphone according to an embodiment. FIG. 2 is a diagram illustrating an example of a hardware configuration of a smartphone used in the embodiment. FIG. 3 is a diagram illustrating a method for measuring blood pressure using the oscillometric method. FIG. 4 is a diagram illustrating an example of a processing block of the smartphone used in the embodiment. FIG. 5 is a diagram illustrating a state in which an indicator is displayed in the embodiment. FIG. 6 is a diagram illustrating the finger position guidance by the guide unit in the embodiment. FIG. 7 is a diagram illustrating a usage mode of the smartphone according to the embodiment. FIG. 8 is a diagram illustrating an example of a processing flow of the smartphone according to the embodiment. FIG. 9 is a diagram illustrating an example of a processing block of a smartphone according to a first modified example. FIG. 10 is a diagram illustrating an example of a processing flow of the smartphone according to the first modified example.

<Embodiment>
The configurations of the embodiments shown below are illustrative, and the disclosed technology is not limited to the configurations of the embodiments. The mobile terminal according to the embodiment includes, for example, a first sensor provided on the back of a plate-shaped housing and pressed by a first finger, a second sensor that detects the pressure applied to the first sensor, a touch screen provided on the front of the housing, and a processing unit that measures blood pressure based on biological information acquired from the first finger by the first sensor. The processing unit displays a guide image on the touch screen that guides the position of the second finger that pinches the housing together with the first finger, moves the guide image in a predetermined direction, acquires the pressure detected by the second sensor, and measures blood pressure based on the biological information acquired from the first sensor when the relationship between the position of the guide image and the pressure detected by the second sensor satisfies a predetermined pressure pattern.

When measuring blood pressure using the oscillometric method, if pressure is not applied to the first sensor according to a specified pressure pattern, the accuracy of blood pressure measurement may decrease or blood pressure may not be measured. If the housing of this mobile device is tilted forward or backward due to pressure applied by the first finger to the first sensor, when the second finger moves according to the guide image, the pressure applied by the first finger to the first sensor changes according to the movement of the second finger. Then, in this mobile device, blood pressure is measured based on the biological information acquired from the first sensor when the relationship between the position of the guide image and the pressure detected by the second sensor satisfies a specified pressure pattern. In other words, with this mobile device, pressure can be easily applied with the fingertip according to the pressure pattern specified for blood pressure measurement by a simple operation of moving according to the guide image on the touch screen.

The following further describes an embodiment in which the above-mentioned mobile terminal is applied to a smartphone with reference to the drawings. FIG. 1 is a diagram illustrating an example of the appearance of a smartphone according to the embodiment. FIG. 1 illustrates an example of the appearance as seen from one side (assumed to be the appearance of the front side) and the appearance as seen from the other side (assumed to be the appearance of the rear side). In FIG. 1, the front side and rear side of the smartphone 100 are interchanged and illustrated by the arrow. The smartphone 100 has a plate-shaped housing 110. The distance (thickness) between the front and rear sides of the housing 110 is short compared to the outer dimensions of the front or rear. In FIG. 1, the upper side facing the paper surface is the upper side of the housing 110, and the lower side facing the paper surface is the lower side of the housing 110.

A touch screen 113 is provided on the front of the housing 110. The touch screen 113 includes a display and a touch panel superimposed on the entire display. The smartphone 100 is provided with the touch screen 113, allowing touch operations with a finger or the like. A speaker 111 is provided in the center of the upper side of the touch screen 113. A microphone 112 for calls is provided in the center of the lower side of the touch screen 113.

A photoplethysmographic sensor 121 and a pressure sensor 122 are provided on the rear surface of the housing 110. The photoplethysmographic sensor 121 and the pressure sensor 122 are provided at positions where, for example, when the housing 110 is held in one hand and the fingertip of the holding hand is extended toward the photoplethysmographic sensor 121, the fingertip reaches the photoplethysmographic sensor 121 from diagonally below the photoplethysmographic sensor 121 and the pressure sensor 122. The photoplethysmographic sensor 121 and the pressure sensor 122 are provided, for example, on the rear surface of the housing 110, approximately in the center in the width direction and on the upper side in the vertical direction. The photoplethysmographic sensor 121 detects the pulse wave of the fingertip in contact with the photoplethysmographic sensor 121. The pressure sensor 122 detects the pressure applied by the fingertip to the photoplethysmographic sensor 121.

Fig. 2 is a diagram showing an example of the hardware configuration of a smartphone used in an embodiment. The smartphone 100 includes a Central Processing Unit (CPU) 101, a main memory unit 102, an auxiliary memory unit 103, a communication unit 104, a speaker 111, a microphone for calling 112, a touch screen 113, a photoplethysmographic sensor 121, a pressure sensor 122, and a tilt sensor 123. The CPU 101, the main memory unit 102, the auxiliary memory unit 103, the communication unit 104, the speaker 111, the microphone for calling 112, the touch screen 113, the photoplethysmographic sensor 121, the pressure sensor 122, and the tilt sensor 123 are interconnected by a connection bus.

The CPU 101 is also called a microprocessor unit (MPU) or a processor. The CPU 101 is not limited to a single processor, and may have a multi-processor configuration. Also, a single CPU 101 connected to a single socket may have a multi-core configuration. At least a part of the processing executed by the CPU 101 is executed by the CPU 10
The processing may be performed by a dedicated processor such as a processor other than the CPU 101, for example, a digital signal processor (DSP), a graphics processing unit (GPU), a numerical calculation processor, a vector processor, or an image processing processor. At least a part of the processing performed by the CPU 101 may be performed by an integrated circuit (IC) or other digital circuit. At least a part of the CPU 101 may include an analog circuit. The integrated circuit includes a large scale integrated circuit (LSI), an application specific integrated circuit (ASIC), and a programmable logic device (PLD). The PLD includes, for example, a field-programmable gate array (FPGA). The CPU 101 may be a combination of a processor and an integrated circuit. The combination is called, for example, a microcontroller unit (MCU), a system-on-a-chip (SoC), a system LSI, a chipset, etc. In the smartphone 100, the CPU 101 expands a program stored in the auxiliary storage unit 103 into a working area of the main storage unit 102, and controls peripheral devices through the execution of the program. This allows the smartphone 100 to execute processing that matches a predetermined purpose. The main storage unit 102 and the auxiliary storage unit 103 are recording media that the smartphone 100 can read.

The main memory unit 102 is exemplified as a memory unit that is directly accessed by the CPU 101. The main memory unit 102 includes a Random Access Memory (RAM) and a Read Only Memory (ROM).

The auxiliary storage unit 103 stores various programs and various data in a readable and writable recording medium. The auxiliary storage unit 103 is also called an external storage device. An operating system (OS), various programs, various tables, etc. are stored in the auxiliary storage unit 103. The OS includes a communication interface program that transfers data with external devices, etc. connected via the communication unit 104. The external devices, etc. include, for example, other information processing devices and external storage devices connected via a computer network, etc. The auxiliary storage unit 103 may be, for example, part of a cloud system, which is a group of computers on a network.

The auxiliary memory unit 103 is, for example, an erasable programmable ROM (EPROM), a solid state drive (SSD), a hard disk drive (HDD), etc.

The communication unit 104 is, for example, an interface with a computer network that communicatively connects the information processing device. The communication unit 104 communicates with an external device via the computer network.

The speaker 111 is a sound source that outputs sound. The speaker 111 outputs sound such as the voice of the other party during a call using the smartphone 100. The call microphone 112 is a microphone that is mainly used for calls. The call microphone 112 accepts input of sound such as the user's voice during a call using the smartphone 100.

The touch screen 113 displays data processed by the CPU 101 and data stored in the main memory unit 102. As described above, the touch screen 113 includes a display and a touch panel. The display may be, for example, a Liquid Crystal Display (LCD), a Plasma Display Panel (PDP), an Elect.
The touch panel is, for example, a capacitive touch panel.

The photoplethysmographic sensor 121 is a sensor that acquires a pulse wave from the fingertip. The photoplethysmographic sensor 121 receives reflected light of light irradiated onto the fingertip and acquires a pulse wave based on the received reflected light. The light source that irradiates the fingertip with light may be integrated with the photoplethysmographic sensor 121 or may be separate. The light source is, for example, a light emitting diode (LED). The photoplethysmographic sensor 121 is an example of a "first sensor." The pulse wave is an example of "biometric information."

The pressure sensor 122 is a sensor that detects pressure applied to the detection surface. The pressure sensor 122 is provided overlapping the photoplethysmographic sensor 121 with the detection surface facing the photoplethysmographic sensor 121. The tilt sensor 123 detects the tilt of the smartphone 100. The tilt sensor 123 detects, for example, the direction of gravitational acceleration, and detects the tilt of the housing 110 based on the detected direction of gravitational acceleration. The pressure sensor 122 is an example of a "second sensor." The tilt sensor 123 is an example of a "third sensor."

<Oscillometric method>
The smartphone 100 measures blood pressure using an oscillometric method. Here, the oscillometric method will be briefly described. For example, in the oscillometric method using a cuff, an air bag called a cuff is wrapped around a limb such as the upper arm. Air is pumped into the cuff wrapped around the limb to increase the pressure (also called cuff pressure). When the cuff pressure is increased to above the systolic blood pressure and then decreased, a vibration component (oscillation) due to arterial pulsation is superimposed on the cuff pressure to calculate the blood pressure value.

Figure 3 explains the measurement method of blood pressure using the oscillometric method. Figure 3 shows the relationship between the pressure and the Korotkoff sounds and oxygenation waveforms observed when a living body is gradually pressurized. Korotkoff sounds are sounds generated by turbulence that occurs in the artery in the part of the body to which external pressure is applied when the body is pressurized or depressurized. With traditional auscultatory methods, the pressure when Korotkoff sounds are generated is the diastolic blood pressure, and the pressure when Korotkoff sounds disappear is the systolic blood pressure. The oxygenation waveform is the waveform of vibrations that occur in the part of the body to which external pressure is applied.

The oscillometric method is a blood pressure measurement method that utilizes the characteristic that when a living body is pressurized or depressurized, the vibration component (oscillation) caused by the pulsation of the artery that occurs in the part to which external pressure is applied gradually increases, reaches a maximum amplitude, and then decreases again. In the oscillometric method, blood pressure values are calculated from the correlation between the amplitude of the oxy- lation waveform instead of Korotkoff sounds and the change in pressure. In other words, the pressure when the amplitude of the oxy- lation waveform is at its maximum is the mean blood pressure. Several methods for calculating systolic and diastolic blood pressure have been proposed, but one example is a method in which the maximum point multiplied by a specified constant (e.g., 0.5) is used as the threshold for systolic blood pressure, the maximum point multiplied by a specified constant (e.g., 0.7) is used as the threshold for diastolic blood pressure, and the cuff pressure corresponding to the point where the envelope of the pulse wave amplitude intersects with each threshold is used as the respective blood pressure value.

Because the oscillometric method is such a measurement method, blood pressure cannot be measured correctly if the pressure applied to the living body is unstable. For example, if the pressure applied to the living body changes suddenly or too slowly, or if there is a temporary fluctuation in pressure reduction during the gradual pressure reduction process, or if there is a temporary fluctuation in pressure reduction during the gradual pressure reduction process, errors will occur in the detection of the pressure pulse waveform, resulting in erroneous detection of the maximum amplitude of the oxygenation waveform, and there is a risk of reduced accuracy in blood pressure measurement.

The following describes the processing blocks and processing flow that facilitate finger pressure application according to a pressure pattern using a smartphone 100 with the above hardware configuration.

<Processing blocks of the smartphone 100>
4 is a diagram showing an example of a processing block of a smartphone used in the embodiment. The smartphone 100 includes a pressure detection unit 11, a tilt detection unit 12, a guidance unit 13, and a measurement unit 14. The smartphone 100 executes the processes of each unit of the smartphone 100, such as the pressure detection unit 11, the tilt detection unit 12, the guidance unit 13, and the measurement unit 14, by the CPU 101 executing a computer program executablely deployed in the main storage unit 102.

The pressure detection unit 11 detects the pressure applied by the fingertip to the photoelectric pulse wave sensor 121 based on the detection value of the pressure sensor 122. The tilt detection unit 12 detects the tilt of the housing 110 based on the detection value of the tilt sensor 123.

The guidance unit 13 displays the inclination detected by the inclination sensor 123 on the touch screen 113. The guidance unit 13 also outputs an indicator indicating the position of the finger to the touch screen 113. The indicator is displayed, for example, below the touch screen 113. FIG. 5 is a diagram illustrating an example of a state in which an indicator is displayed in the embodiment. In FIG. 5, for reference, the positions of the photoelectric pulse wave sensor 121 and the pressure sensor 122 provided on the back surface of the housing 110 are illustrated by dotted lines. The guidance unit 13 displays an indicator 212 below the touch screen 113. The guidance unit 13 may further display a message on the touch screen 113 encouraging the user to touch the indicator 212. The guidance unit 13 may also display an inclination gauge 213 that visually illustrates the inclination of the housing 110. In the inclination gauge 213 illustrated in FIG. 5, a plurality of rectangles are arranged in a row, and the rectangle corresponding to the inclination of the housing 110 is displayed in a manner different from the other rectangles.

When the guidance unit 13 detects a touch operation on the index 212, the guidance unit 13 guides the movement of the finger touching the touch screen 113 by moving the index 212 upward. In other words, the guidance unit 13 guides the movement of the finger touching the touch screen 113 by moving the index 212 so as to approach the photoplethysmographic sensor 121. The direction in which the index 212 moves from below to above is an example of a "predetermined direction".

Figure 6 is a diagram that shows a schematic of the guidance of the finger position by the guidance unit in the embodiment. In Figure 6, the positions of the photoelectric pulse wave sensor 121 and the indicator 212 are also shown. When starting blood pressure measurement with the smartphone 100, the photoelectric pulse wave sensor 121 is pressed from the back to the front by the fingertip F1 in a state in which the housing 110 is tilted by lifting the upper end of the housing 110 more than the lower end. Then, the fingertip F2 is touched at the position of the indicator 212. In other words, the housing 110 is sandwiched between the fingertips F1 and F2. The indicator 212 is an example of a "guidance image".

The guide unit 13 moves the index 212 on the touch screen 113 so as to approach the photoplethysmographic sensor 121. As a result, the fingertip F2 moves while maintaining contact with the touch screen 113. In FIG. 6, the direction of movement of the index 212 and fingertip F2 is illustrated by the arrow Y1, and the position of the fingertip F2 after the movement is illustrated by the dotted line.

Here, the mass of the smartphone 100 is m, the angle between the horizontal plane D1 and the housing 110 is θ, the distance from the bottom end of the housing 110 to the photoplethysmographic sensor 121 is L1, the distance from the bottom end of the housing 110 to the center of gravity of the smartphone 100 is L2, the distance from the bottom end of the housing 110 to the fingertip F2 is L3, the force with which the fingertip F1 presses the photoplethysmographic sensor 121 is P1, and the force with which the fingertip F2 presses the touch screen 1
If the force pushing 13 is P2 and the gravitational acceleration is g, the following equation (1) holds.

From equation (1), the pressure P1 of the fingertip F1 against the photoplethysmographic sensor 121 can be calculated from the following equation (2).

The distance L1 from the bottom end of the housing 110 to the photoplethysmographic sensor 121 is a fixed value according to the design of the smartphone 100. In addition, the distance L2 from the bottom end of the housing 110 to the center of gravity is also a fixed value according to the design of the smartphone 100. Furthermore, if the inclination θ of the housing 110 is constant, then "mg·cosθ" is a fixed value. From equation (2), it can be seen that the greater the force P2 with which the fingertip F2 presses the touch screen 113, the greater the force P1 applied to the photoplethysmographic sensor 121. It can also be seen that the greater the distance L3 from the bottom end of the housing 110 to the fingertip F2, the greater the force P1 applied to the photoplethysmographic sensor 121.

That is, by moving fingertip F2 in accordance with the movement of index 212, the pressure applied by fingertip F1 to photoplethysmographic sensor 121 can be gradually increased. In the smartphone 100, if the force P2 with which fingertip F2 presses the touch screen 113 is constant, by moving fingertip F2 in accordance with index 212, the pressure applied to photoplethysmographic sensor 121 can be easily controlled.

The position of the indicator 212 with respect to the force P1 along the pressure pattern may be set to the position L3 determined by the following formula (3) obtained by modifying formula (2).

Returning to FIG. 4, when the measurement unit 14 detects a touch operation on the index 212 while the tilt detected by the tilt detection unit 12 is within the allowable range stored in the auxiliary storage unit 103, the measurement unit 14 starts blood pressure measurement. When the position of the index 212 and the pressure detected by the pressure detection unit 11 satisfy a pressure pattern previously stored in the auxiliary storage unit 103, the measurement unit 14 acquires a pulse wave from the photoelectric pulse wave sensor 121. The pressure pattern is, for example, information that associates the position of the index 212 with the pressure detected by the pressure detection unit 11. When the measurement unit 14 acquires a pulse wave sufficient for blood pressure measurement, it calculates blood pressure based on the acquired pulse wave.

<Use of smartphone 100>
FIG. 7 is a diagram illustrating a usage mode of the smartphone according to the embodiment. For example, the smartphone 100 is placed on the right hand with its lower end in contact with the palm of the right hand and the tip F1 of the middle finger of the right hand in contact with the photoelectric pulse wave sensor 121. Therefore, the lower end of the housing 110 is supported by the palm of the right hand, and the upper end side of the housing 110 is supported by the tip F1 in contact with the photoelectric pulse wave sensor 121. Therefore, the smartphone 100 is supported with the housing 110 inclined with respect to the palm of the right hand. The smartphone 100 supported in this manner performs blood pressure measurement while the tip F2 of the index finger of the left hand touching the indicator 212 is guided by the indicator 212. Note that in FIG. 7, the middle finger of the right hand is shown as the tip F1,
Although the index finger of the left hand is exemplified as the fingertip F2, the fingertip F1 and the fingertip F2 are not limited thereto. The fingertip F1 and the fingertip F2 may be other fingers. The hand on which the smartphone 100 is placed may be the left hand or the right hand. Furthermore, blood pressure measurement using the smartphone 100 may be performed using either the right hand or the left hand. For example, the smartphone 100 may be placed on the palm of the right hand, the tip of the middle finger of the right hand may be in contact with the photoelectric pulse wave sensor 121, and the thumb of the right hand may touch the index 212.

<Processing flow of the smartphone 100>
Fig. 8 is a diagram showing an example of a processing flow of the smartphone according to the embodiment. As illustrated in Fig. 7, the smartphone 100 starts blood pressure measurement in a state in which the lower end of the housing 110 is in contact with the palm of the hand and the photoplethysmographic sensor 121 is supported by the fingertip F1. Hereinafter, an example of the processing flow of the smartphone 100 will be described with reference to Fig. 8.

At T1, the guidance unit 13 displays the tilt detected by the tilt detection unit 12 on the touch screen 113. At T2, the guidance unit 13 displays an indicator 212 on the touch screen 113. The indicator 212 is displayed, for example, in the center of the width of the touch screen 113 and below the touch screen 113.

At T3, the measurement unit 14 determines whether or not a touch operation has been performed on the indicator 212. If a touch operation has been performed (YES at T3), the process proceeds to T4. If a touch operation has not been performed (NO at T3), the process at T3 is repeated.

At T4, the guidance unit 13 calculates the position of the indicator 212 to be moved along the pressure pattern. The guidance unit 13 calculates the position of the indicator 212 using, for example, equation (3). At T5, the guidance unit 13 displays the indicator 212 at the position calculated at T4.

At T6, the measurement unit 14 acquires a pulse wave based on the detection value of the photoelectric pulse wave sensor 121, and acquires pressure from the pressure detection unit 11. The measurement unit 14 associates the acquired pulse wave with the pressure and stores them in the auxiliary storage unit 103.

At T7, the measurement unit 14 determines whether the pressure application pattern stored in the auxiliary memory unit 103 has ended. If the pressure application pattern has ended (YES at T7), the process proceeds to T8. If the pressure application pattern has not ended (NO at T7), the process proceeds to T4.

At T8, the measurement unit 14 calculates blood pressure based on the pressure and pulse wave acquired at T7. For example, the measurement unit 14 extracts a pulse wave acquired when pressure is applied according to a pressure pattern based on the pressure stored in the auxiliary storage unit 103. The measurement unit 14 may calculate blood pressure based on the extracted pulse wave.

<Effects of the embodiment>
In the embodiment, the photoplethysmographic sensor 121 and the fingertip F1 come into contact with each other while the housing 110 of the smartphone 100 is tilted. In this state, the smartphone 100 displays an indicator 212 on the touch screen 113 to guide the position where the fingertip F2 comes into contact. As described above, when the fingertip F2 is moved on the touch screen 113 so as to approach the photoplethysmographic sensor 121 asymptotically, the pressure applied to the photoplethysmographic sensor 121 increases. The smartphone 100 moves the indicator 212 so that pressure is applied to the photoplethysmographic sensor 121 according to the pressure pattern. Therefore, according to the present embodiment, by moving the fingertip F2 according to the indicator 212, pressure can be easily applied to the photoplethysmographic sensor 121 according to the pressure pattern.

In the embodiment, the guide unit 13 displays the tilt gauge 213 on the touch screen 113. The tilt gauge 213 displays the tilt of the housing 110 in a manner that makes it easy to visually understand. Therefore, by checking the tilt gauge 213, the user of the smartphone 100 can easily keep the tilt of the housing 110 constant. In other words, according to the embodiment, fluctuations in the tilt of the housing 110 during blood pressure measurement are suppressed.

<First Modification>
In the embodiment, the index 212 is moved so as to be displayed at a position where pressure is applied according to the pressure pattern. In the first modified example, a modified example in which the position of the index 212 is corrected when the pressure applied to the photoplethysmographic sensor 121 deviates from the pressure pattern will be described. The same components as in the embodiment will be given the same reference numerals and their description will be omitted. The first modified example will be described below with reference to the drawings.

Figure 9 is a diagram showing an example of a processing block of a smartphone according to a first modified example. The smartphone 100a illustrated in Figure 9 differs from the smartphone 100 according to the embodiment in that it includes a guidance unit 13a instead of the guidance unit 13.

In addition to the processing of the guidance unit 13, the guidance unit 13a further executes a correction process to correct the position of the indicator 212 when the pressure acquired by the pressure detection unit 11 does not follow the pressure pattern. For example, when the acquired pressure is higher than the pressure specified by the pressure pattern, the guidance unit 13a executes a correction process to move the position of the indicator 212 downward to a position corresponding to the pressure specified by the pressure pattern. Also, for example, when the detected pressure is lower than the pressure specified by the pressure pattern, the guidance unit 13a executes a correction process to move the indicator 212 upward to a position corresponding to the pressure specified by the pressure pattern.

Figure 10 is a diagram showing an example of a processing flow of a smartphone according to the first modified example. Below, an example of the processing flow of the smartphone 100a is described with reference to Figure 10.

In J1, the guidance unit 13a acquires pressure from the pressure detection unit 11. In J2, the guidance unit 13a determines whether the pressure acquired in J1 is in accordance with the pressure pattern. If the pressure acquired in J1 is in accordance with the pressure pattern (YES in J2), the process proceeds to J3. If the pressure acquired in J1 is not in accordance with the pressure pattern (NO in J2), the process proceeds to J4.

In J3, the measurement unit 14 associates the pressure acquired by the guidance unit 13a in J1 with the detection value of the photoelectric pulse wave sensor 121 and stores them in the auxiliary memory unit 103.

In J4, the guidance unit 13a performs a correction process to correct the position of the indicator 212. The guidance unit 13a calculates the position of the indicator 212 according to the pressure acquired in J1.

In the first modified example, the smartphone 100a corrects the position of the indicator 212 when the acquired pressure deviates from the pressure application pattern. Therefore, the smartphone 100a can increase the possibility of continuing blood pressure measurement even when the acquired pressure deviates from the pressure application pattern.

The smartphone 100a may also interrupt blood pressure measurement if the deviation of the acquired pressure from the pressure pattern falls outside an acceptable range.

<Other variations>
The speed at which the guidance unit 13 moves the indicator 212 is not limited to a constant speed. The guidance unit 13 may change the moving speed of the indicator 212 according to the pressure detected by the pressure detection unit 11. For example, when the detected pressure is higher than the pressure along the pressure pattern, the guidance unit 13 may decrease the upward moving speed of the indicator 212. Furthermore, when the detected pressure is lower than the pressure along the pressure pattern, the guidance unit 13 may increase the upward moving speed of the indicator. By performing such processing, even if the pressure detected by the pressure detection unit 11 once deviates from the pressure pattern, the smartphone 100 can return the pressure to the pressure pattern by changing the moving speed of the fingertip F2.

In the embodiment, the guidance unit 13 moves the indicator 212 displayed below the touch screen 113 upward. However, the direction of movement of the indicator 212 is not limited to from bottom to top. The guidance unit 13 may also move the indicator 212 displayed above the touch screen 113 downward. In such a case, the guidance unit 13 may move the indicator 212 along a pressure pattern in which the pressure on the photoplethysmographic sensor 121 is gradually reduced.

In the embodiment, the guide unit 13 moves the indicator 212 along the vertical direction of the housing 110. However, the movement direction of the indicator 212 is not limited to the vertical direction. For example, the guide unit 13 may move the indicator 212 in the horizontal direction of the housing 110. For example, when the smartphone 100 is placed on the palm with the fingers facing sideways, the indicator 212 may be moved in the width direction (horizontal direction) of the housing 110. That is, when the smartphone 100 is supported with the upper end of the housing 110 raised, the guide unit 13 may move the indicator 212 from the bottom to the top of the touch screen 113. Also, when the smartphone 100 is supported with the left end of the housing 110 raised, the guide unit 13 may move the indicator 212 from the right end of the touch screen 113 toward the left. Furthermore, when the smartphone 100 is supported with the right end of the housing 110 lifted, the guide unit 13 may move the touch screen 113 from the left end toward the right. In other words, the guide unit 13 may determine the orientation of the smartphone 100 (housing 110) according to the tilt detected by the tilt sensor 123, and may determine the movement direction of the indicator 212 according to the determined orientation of the housing 110. Furthermore, even if the movement direction of the indicator 212 is a direction other than the up-down direction, the guide unit 13 may determine the position of the indicator 212 so as to follow the pressure pattern.

In the embodiment and the first modified example, a photoelectric pulse wave sensor 121 is used to acquire the pulse wave, but the sensor used to acquire the pulse wave is not limited to the photoelectric pulse wave sensor 121. Examples of sensors used to acquire the pulse wave include a Doppler type and an optical fiber type. Such sensors can be manufactured using technologies such as piezoelectric ceramics (PZT), Fiber Bragg Grating (FBG), and Micro Electro Mechanical System (MEMS).

The embodiments and variations disclosed above can be combined with each other.

<<Computer-readable recording medium>>
An information processing program that causes a computer or other machine or device (hereinafter, computer, etc.) to realize any of the above functions can be recorded on a recording medium that can be read by the computer, etc. Then, the computer, etc. can provide the function by reading and executing the program from the recording medium.

Here, a computer-readable recording medium refers to a recording medium that stores information such as data and programs electrically, magnetically, optically, mechanically, or chemically and can be read by a computer. Examples of such recording media that can be removed from a computer include flexible disks, magneto-optical disks, and Com.
Examples of such a recording medium include compact disc read only memory (CD-ROM), compact disc recordable (CD-R), compact disc rewritable (CD-RW), digital versatile disc (DVD), Blu-ray disc (BD), digital audio tape (DAT), 8mm tape, memory cards such as flash memory, etc. Also, examples of recording media fixed to a computer, etc. include hard disks and ROMs.

100, 100a: Smartphone 110: Housing 101: CPU
102: Main memory unit 103: Auxiliary memory unit 104: Communication unit 111: Speaker 112: Microphone for calls 113: Touch screen 121: Photoplethysmography sensor 122: Pressure sensor 123: Tilt sensor 11: Pressure detection unit 12: Tilt detection unit 13, 13a: Guide unit 14: Measurement unit 212: Indicator 213: Tilt gauge

Claims (7)

a first sensor provided on a rear surface of a plate-shaped housing and pressed by a first finger;
a second sensor for detecting a pressure applied to the first sensor;
A touch screen provided on a front surface of the housing;
a processing unit that measures blood pressure based on a pulse wave acquired from the first finger by the first sensor,
The processing unit includes:
displaying on the touch screen a guide image for guiding a position of a second finger that is to be placed on the housing together with the first finger;
The guide image is moved in a predetermined direction, and the pressure detected by the second sensor is acquired.
measuring blood pressure based on the pulse wave acquired from the first sensor when a relationship between a position of the guide image and the pressure detected by the second sensor satisfies a predetermined pressure pattern;
Mobile device. When the pressure detected by the second sensor does not satisfy the predetermined pressure pattern, the processing unit moves the guide image to a position according to the detected pressure.
The mobile terminal according to claim 1 . the processing unit changes a speed at which the guide image is moved in accordance with a relationship between the pressure detected by the second sensor and a pressure defined by the pressure pattern.
The mobile terminal according to claim 1 . a third sensor for detecting a tilt of the housing;
The processing unit causes the touch screen to display the tilt detected by the third sensor.
The mobile terminal according to any one of claims 1 to 3. the processing unit determines an orientation of the housing based on the tilt detected by the third sensor, and determines the predetermined direction in accordance with the determined orientation.
The mobile terminal according to claim 4. A computer comprising: a first sensor provided on a rear surface of a plate-shaped housing and pressed by a first finger; a second sensor that detects pressure applied to the first sensor; and a touch screen provided on a front surface of the housing,
displaying on the touch screen a guide image for guiding a position of a second finger that is to be placed on the housing together with the first finger;
The guide image is moved in a predetermined direction, and the pressure detected by the second sensor is acquired.
measuring blood pressure based on the pulse wave acquired from the first sensor when the relationship between the position of the guide image and the pressure detected by the second sensor satisfies a predetermined pressure pattern;
How to measure blood pressure. A computer is provided with a first sensor provided on a rear surface of a plate-shaped housing and pressed by a first finger, a second sensor that detects pressure applied to the first sensor, and a touch screen provided on a front surface of the housing,
displaying, on the touch screen, a guide image for guiding a position of a second finger that is to pinch the housing together with the first finger;
moving the guide image in a predetermined direction and acquiring a pressure detected by the second sensor;
measuring blood pressure based on the pulse wave acquired from the first sensor when a relationship between the position of the guide image and the pressure detected by the second sensor satisfies a predetermined pressure pattern;
Blood pressure measurement program.

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