DE102015210622A1

DE102015210622A1 - Biological gas detection device, method, and program

Info

Publication number: DE102015210622A1
Application number: DE102015210622.5A
Authority: DE
Inventors: Miyuki Kodama; Yasuhiro Kasahara; Naotaka MINAGAWA; Ayumi Sano; Yasuhiro Setogushi; Kimiko Kato; Takeshi Eda
Original assignee: Figaro Engineering Inc; Tanita Corp
Current assignee: Figaro Engineering Inc; Tanita Corp
Priority date: 2014-06-11
Filing date: 2015-06-10
Publication date: 2015-12-17
Also published as: JP6268484B2; DE102015210622A9; JP2016001126A

Abstract

The present invention provides a biological gas detection device, method and program capable of detecting a target gas with good accuracy even under the influence of an interfering gas. A biological gas detection device 10 includes a semiconductor gas sensor 14 having sensitivity to a target gas and an interfering gas that are contained in a biological gas, and a fuel cell gas sensor 16 having sensitivity to the interfering gas contained in the biological gas. The biological gas detection device 10 acquires a concentration of the target gas based on an output value of the semiconductor gas sensor 14 and an output value of the fuel cell gas sensor 16, and displays information that corresponds to the acquired concentration of the target gas on a display section 20.

Description

[Technical Field]
The present invention relates to a biological gas detection device, method, and program.
[Background Art]
Hitherto existing technology has detected biological gas produced by a biological body using a gas sensor, and acquired information related to the health state of the biological body by calculating the concentration of the biological gas. However, many interfering gases other than the target gas to be detected are contained in biological gas.
A semiconductor sensor is, for example, employed to detect biological gas, however it is difficult to measure the concentration of only the target gas with good accuracy due to the semiconductor sensor not only reacting with the target gas, but also reacting with interfering gases.
As technology to measure the concentration of a target gas in a biological gas with good accuracy, there is technology that combines a separator column and a semiconductor gas sensor, such as described for example in Patent Document 1. In the technology of Patent Document 1, the sample gas is introduced into a separator column filled with a carrier gas and a filler, and components separated by differences in retention times due to interactions between the components in the sample gas and the filler are extracted from the column and detected using a gas detector, to thereby obtain a gas chromatogram.
Moreover, technology described in Patent Document 2 uses a semiconductor gas sensor having high sensitivity to the target gas and a semiconductor gas sensor having sensitivity to interfering gas to calculate the concentration of the target gas.
[Prior Art Documents]
[Patent Documents]

Patent Publication 1: Japanese Patent Application Laid-Open (JP-A) No. 2007-57392
Patent Publication 2: International Publication (WO) No. 2012/165182

[DISCLOSURE OF INVENTION]
[Problem to be Solved by Invention]
However, the technology of Patent Document 1 has the problem that the device is both bulky and costly, and is not appropriate for simple measurements.
Moreover, the technology of Patent Document 2 has the problem that it is still difficult to subtract only the portion of influence corresponding to the interfering gas with good accuracy even by combining the use of semiconductor gas sensors with different sensitivity characteristics. There is therefore a problem that the sensitivity of the semiconductor gas sensor itself may be lowered.
An object of the present invention is to provide a biological gas detector device, method, and program capable of detecting a target gas with good accuracy even under the influence of an interfering gas.
[Means for Solving Problem]
In order to solve the above problem, a biological gas detection device according to a first aspect of the present invention includes: a semiconductor gas sensor having sensitivity to a target gas and to an interfering gas that are contained in a biological gas; an electrochemical gas sensor having sensitivity to the interfering gas contained in the biological gas; a target gas concentration acquisition means for acquiring a concentration of the target gas based on an output value of the semiconductor gas sensor and an output value of the electrochemical gas sensor; and an output means for outputting information according to the concentration of the target gas.
In a second aspect, configuration may be made to further include a pressure sensor that detects a pressure of breath, wherein the target gas concentration acquisition means acquires the concentration of the target gas, under the influence of the interfering gas, which corresponds to the output value of the semiconductor gas sensor at a breath-end acquisition timing determined based on the output value of the pressure sensor.
In a third aspect, configuration may be made to further include a pressure sensor that detects a pressure of breath, and an interfering gas provisional concentration acquisition means for acquiring a provisional concentration of the interfering gas, which corresponds to the output value of the electrochemical gas sensor at the breath-end acquisition timing determined based on the output value of the pressure sensor.
In a fourth aspect, configuration may be made such that the output means outputs a provisional concentration of the interfering gas to a display means after the provisional concentration of the interfering gas has been acquired.
In a fifth aspect, configuration may be made such that the target gas concentration acquisition means acquires a provisional concentration of the target gas being excluded of influence of the interfering gas, which corresponds to the output value of the semiconductor gas sensor and the output value of the electrochemical gas sensor.
In a sixth aspect, configuration may be made such that the output means outputs a provisional concentration of the target gas to a display means after the provisional concentration of the target gas has been acquired.
In a seventh aspect, configuration may be made to further include an interfering gas final concentration acquisition means for acquiring a final concentration of the interfering gas, which corresponds to an integrated value of the output values of the electrochemical gas sensor from a time at which the output value of the electrochemical gas sensor has reached a peak value to a time at which the output value has returned to a steady-state value.
In an eighth aspect, configuration may be made to further include an estimating means for estimating the steady-state value based on a change in the output value of the electrochemical gas sensor, wherein the interfering gas final concentration acquisition means acquires the final concentration of the interfering gas based on the steady-state value estimated by the estimating means.
In a ninth aspect, configuration may be made such that the target gas concentration acquisition means acquires a final concentration of the target gas based on the concentration of the target gas under the influence of the interfering gas and based on the final concentration of the interfering gas.
In a tenth aspect, configuration may be made to further include a physical condition risk information acquisition means for acquiring physical condition risk information, related to a degree of physical condition risk, based on the concentration of the target gas and the concentration of the interfering gas, wherein the output means outputs the physical condition risk information.
In an eleventh aspect, configuration may be made such that the physical condition risk information includes at least one of a physical condition risk level, or advice information that corresponds to the concentration of the target gas and to the concentration of the interfering gas.
In a twelfth aspect, configuration may be made to further include a cap that covers an air intake into which the biological gas is blown, and an adsorbent that adsorbs a contaminating substance that contaminates at least one of the semiconductor gas sensor and the electrochemical gas sensor.
In a thirteenth aspect, configuration may be made to further include a detection means for detecting whether the cap is open or closed, and a warning means for warning that the adsorbent should be replaced when the output value of the semiconductor gas sensor has reached a predetermined threshold value or greater in a closed state of the cap.
In a fourteenth aspect, configuration may be made such that opening and closing the cap also functions to switch a power switch ON or OFF.
In a fifteenth aspect, configuration may be made to further include an alert means for alerting when a predetermined period of time has elapsed in an opened state of the cap.
In a sixteenth aspect, configuration may be made such that the target gas is acetone or acetaldehyde, and the interfering gas is ethanol.
A biological gas detection method according to a seventeenth aspect includes, based on an output value of a semiconductor gas sensor having sensitivity to a target gas and to an interfering gas that are contained in a biological gas, and based on an output value of an electrochemical gas sensor having sensitivity to the interfering gas contained in the biological gas, acquiring a concentration of the target gas, and outputting information according to the concentration of the target gas.
A biological gas detection program according to an eighteenth aspect causes a computer to execute processing. The processing includes, based on an output value of a semiconductor gas sensor having sensitivity to a target gas and to an interfering gas that are contained in a biological gas, and based on an output value of an electrochemical gas sensor having sensitivity to the interfering gas contained in the biological gas, acquiring a concentration of the target gas, and outputting information according to the concentration of the target gas.
[Advantageous Effects of Invention]
The present invention exhibits the advantageous effect of enabling a target gas to be detected with good accuracy even under the influence of an interfering gas.
[BRIEF DESCRIPTION OF DRAWINGS]
1 is a block diagram of a biological gas detection device.
2 is a diagram illustrating the extent of influences of interfering gases on a semiconductor gas sensor.
3 is an external view of a biological gas detection device.
4 is a flow chart of processing by a biological gas detection program.
5 is a diagram illustrating an example of a waveform of output values of a pressure sensor.
6 is a diagram illustrating an example of table data expressing correspondence relationships between output values of a semiconductor gas sensor and concentrations of acetone under the influence of ethanol.
7 is a diagram illustrating an example of table data expressing correspondence relationships between output values of a fuel cell gas sensor and provisional concentrations of ethanol.
8 is a diagram illustrating an example of table data expressing correspondence relationships between output values of a semiconductor gas sensor, output values of a fuel cell gas sensor, and concentrations of acetone excluding the influence of ethanol.
9 is a diagram illustrating an example of table data expressing correspondence relationships between concentrations of acetone under the influence of ethanol, provisional concentrations of ethanol, and concentrations of acetone excluding the influence of ethanol.
10 is a diagram illustrating an example of a waveform of output values of a fuel cell gas sensor.
11 is a diagram illustrating an example of table data expressing correspondence relationships between an integrated value of the output values of a fuel cell gas sensor and final concentrations of ethanol.
12 is a diagram illustrating an example of table data expressing correspondence relationships between concentrations of acetone, final concentrations of ethanol, and physical condition risk information.
13 is a diagram to explain correlation between concentrations of acetone measured using a single semiconductor gas sensor, and concentrations of acetone measured using gas chromatography.
14 is a diagram to explain correlation between concentrations of acetone measured using a semiconductor gas sensor and a fuel cell gas sensor, and concentrations of acetone measured using gas chromatography
15 is a diagram illustrating an example of table data expressing correspondence relationships between output values of a semiconductor gas sensor, integrated values of the output values of a fuel cell gas sensor, and concentrations of acetone excluding the influence of ethanol.
16 is a diagram illustrating an example of table data expressing correspondence relationships between concentrations of acetone under the influence of ethanol, final concentrations of ethanol, and final concentrations of acetone excluding the influence of ethanol.
[DESCRIPTION OF EMBODIMENTS]
Explanation follows regarding an exemplary embodiment of the present invention.
1 is a configuration diagram of a biological gas detection device 10 according to the present exemplary embodiment. As illustrated in 1, the biological gas detection device 10 includes a controller 12, a sensor section 13, a display section 20, an operation section 22, a timer 24, and a communication section 26. The sensor section 13 includes a semiconductor gas sensor 14, a fuel cell gas sensor (electrochemical sensor) 16, and a pressure sensor 18. The semiconductor gas sensor 14 includes a metal oxide semiconductor, such as SnO₂, a heater, and an electrode. The metal oxide semiconductor has a resistance value that changes when an interfering gas or an obstructive gas is adsorbed. The semiconductor gas sensor 14 lacks quantitative performance and selectivity to gas, and has high sensitivity to trace quantities of acetone or the like. The fuel cell gas sensor 16 includes an electrolyte such as sulfuric acid, a proton conducting membrane, or the like, a working electrode, and a counter electrode, and atmosphere of a fixed volume is introduced into the fuel cell gas sensor 16 using a solenoid, pump, or the like, not illustrated in the drawings. Ethanol in the introduced atmosphere is broken down by an electrochemical reaction, with a reaction current output when this occurs. The integrated value of the reaction current is proportional to the quantity of ethanol, enabling quantification of the ethanol.
The controller 12 includes a Central Processing Unit (CPU) 12A, Read Only Memory (ROM) 12B, Random Access Memory (RAM) 12C, non-volatile memory 12D, and an input/output interface (I/O) 12E, each connected together through a bus 12F. In this configuration, a biological gas detection program that causes the CPU 12A of the controller 12 to execute biological gas detection processing, described below, is written to the non-volatile memory 12D, for example, and read and executed by the CPU 12A. The biological gas detection program may be provided on a recording medium, such as a CD-ROM or a memory card, and may be downloaded from a server, not illustrated in the drawings.
The semiconductor gas sensor 14, the fuel cell gas sensor 16, the pressure sensor 18, the display section 20, the operation section 22, the timer 24, and the communication section 26 are connected to the I/O 12E.
The semiconductor gas sensor 14 is a gas sensor having sensitivity to target gas and interfering gas contained in a biological gas in breath blown thereto by a user. The semiconductor gas sensor 14 detects the biological gas containing the target gas and the interfering gas, and outputs the concentration of the detected biological gas as a voltage value. The biological gas in the breath contains various gases, such as ketones, ethanol, acetaldehydes, hydrogen, water vapor, methane, and mouth odors. Ketones is a general term used here to indicate at least one compound selected from acetoacetic acid, 3-hydroxy butyric acid(-hydroxy butyric acid), or acetone.
Explanation follows in the present exemplary embodiment of a case in which acetone is the target gas, and ethanol is an interfering gas. Acetone is a byproduct of metabolizing fat, and the acetone concentration corresponds to the amount of fat burned. Fat is not burned when there is a surplus of carbohydrate energy in the body, and so the acetone concentration is low. Fat is burned when there is insufficient carbohydrate energy in the body, and so the acetone concentration rises. This thereby enables the amount of fat burned to be known from the acetone concentration.
The fuel cell gas sensor 16 is a gas sensor having selective sensitivity to an interfering gas, draws in the biological gas by opening a solenoid valve, and detects the interfering gas contained in the biological gas that has been drawn. The fuel cell gas sensor 16 outputs the concentration of the detected interfering gas as a voltage value. The fuel cell gas sensor 16 is a type of electrochemical gas sensor. Electrochemical gas sensors, as well as fuel cell gas sensors, also include for example potentiostatic electrolysis sensors, three-electrode electrochemical sensors, and the like. Explanation follows of a case in the present exemplary embodiment in which a fuel cell gas sensor is employed, however another electrochemical gas sensor may be employed.
The reason that ethanol was selected as the subject for interfering gas in the present exemplary embodiment is as follows. Namely, based on the results of measuring the concentration of interfering gases in an environment in which various interfering gases are present in breath and the environment, ethanol was found to have the highest influence in the results of multiple regression analysis using the concentration of main types of interfering gas as explanatory variables, and the amount of influence on the semiconductor sensor as the response variable. 2 illustrates the results of multiple regression analysis.
The pressure sensor 18 detects the pressure of breath being blown thereon by a user. The pressure sensor 18 output the magnitude of the detected pressure as a voltage value.
The display section 20 is, for example, configured by a liquid crystal panel. The display section 20 displays, for example, various setting screen images, and various types of screen images such as detection results.
The operation section 22 is an operation section for performing various types of operation, including user information input operations.
3 illustrates the external appearance of the biological gas detection device 10. As illustrated in 3, an air intake 30 is provided to a main body of the biological gas detection device 10 for a user to blow breath into, in a configuration capable of covering the air intake 30 by closing a cap 10B. A user opens the cap 10B and blows breath into the air intake 30, and the target gas and interfering gas contained in the biological gas that has been blown in is thereby detected. In the example in 3, the cap 10B is configured so as to open and close at one side, while being supported at the other side, however there is no limitation thereto, and configuration may be made such that the cap 10B slides as a whole in the up-down direction.
An adsorbent 32 is provided inside the cap 10B for adsorbing biological gas. The adsorbent 32 is a material that adsorbs at least one contaminating substance that contaminates at least one of the semiconductor gas sensor 14 or the fuel cell gas sensor 16, and may employ, for example, activated carbon, zeolite, a molecular sieve, silica gel, or the like. Providing the adsorbent 32 within the cap 10B in this manner enables air in the closed space between the main body 10A and the cap 10B to be cleaned when the cap 10B is closed, after detecting the biological gas and isolating the semiconductor gas sensor 14 and the fuel cell gas sensor 16 from the external atmosphere. This thereby enables contaminating of the semiconductor gas sensor 14 and the fuel cell gas sensor 16 to be prevented. The adsorbent 32 may be provided at a location facing toward the semiconductor gas sensor 14 and the fuel cell gas sensor 16 so as to intrude into the flow path of gas when the cap 10B has been shut. The adsorbent 32 may also be provided to a storage cover and recharging cradle for the biological gas detection device 10.
As illustrated in 3, the operation section 22 is configured to include plural operation buttons 22A to 22C. Various functions are allocated to the respective operation buttons 22A to 22C, such as a power ON/OFF function, input functions for various information such as user information, and a scroll function for screen images.
As illustrated in 3, a conductive member 34A is provided to the main body 10A of the biological gas detection device 10, and a conductive member 34B is provided inside the cap 10B, such that the conductive members 34A, 34B make contact with each other and conduct when the cap 10B is closed. The conductive members 34A, 34B function as a portion of a detection means to detect whether the cap is open or closed.
The display section 20 and the operation section 22 may be configured by a touch panel, enabling operation by direct touch contact with the screen.
The timer 24 includes a function to acquire the current time, and a timer function to time durations.
The communication section 26 includes a function to perform transmission and reception of information to and from an external device, either by wireless communication or wired communication. The biological gas detection device 10 is thereby able to communicate with an external device, such as, for example, a smartphone, a mobile phone, a tablet terminal, or a personal computer.
Explanation next follows regarding processing by a biological gas detection program executed by the CPU 12A of the controller 12 as operation of the present exemplary embodiment, with reference to the flowchart illustrated in 4. The processing illustrated in 4 is executed when a user operates the operation section 22 of the biological gas detection device 10, and executes when execution of the biological gas detection program has been instructed.
At step S100, a message is displayed on the display section 20 prompting a user to open the cap 10B and blow breath onto the bio gas detection device 10. The user accordingly opens the cap 10B and blows breath into the air intake 30.
At step S100, the output value of the pressure sensor 18, namely the magnitude of the pressure, is acquired, and determination is made as to whether or not breath has been blown onto the bio gas detection device 10 by determining whether or not the acquired output value of the pressure sensor 18 is a predetermined threshold value TH illustrated in 5 or greater. Processing transitions to step S102 when determined that breath has been blown onto the bio gas detection device 10, and when determined that breath has not been blown thereon, standby is performed until breath has been blown thereon.
At step S102, a breath-end acquisition timing is set so as to obtain the end of a breath. The reason that the breath-end acquisition timing is decided in this manner is that acetone as the target gas and ethanol as the interfering gas are mainly contained in the breath-end. This thereby enables the concentrations of the acetone and the ethanol to be acquired with good accuracy by detecting the acetone and the ethanol acquired at the breath-end.
Assuming that the end of a breath is obtained by a user blowing a volume A (ml) of breath onto the bio gas detection device 10. The "volume A (ml)" is, for example, equivalent to the amount of air breathed in and out one time. Since there is a strong correlation between an output value B (V) of the pressure sensor 18 and the breath flow rate C (ml/s), the flow rate C (ml/s) corresponding to the output value B (V) of the pressure sensor 18 can be obtained by an equation to convert the pressure sensor output value B (V) into the flow rate C (ml/s), or from table data expressing correspondence relationships between the pressure sensor output value B (V) and the flow rate C (ml/s). A time D (s) required for a volume A (ml) of breath to be blown out from when blowing onto the bio gas detection device 10 was detected at step S100, namely, the breath end acquisition time D(s), is thus obtained by the following equation. D(s) = A(ml)/C(ml/s) Equation (1)
Thus at step S102, the flow rate C (ml/s) corresponding to the output value B (V) of the pressure sensor 18 is acquired using the conversion equation of the table data, and the breath-end acquisition timing D (s) is acquired by substituting the acquired flow rate C into Equation (1).
5 illustrates an example of a waveform of output values of the pressure sensor 18. As illustrated in 5, the breath-end acquisition timing D (s) is the duration from ts to te when the integrated value of the output values of the pressure sensor 18 (the region shaded by diagonal lines in 5), during the period from time ts when blowing of breath onto the bio gas detection device 10 started (the point in time when the output value of the pressure sensor 18 reached the threshold value TH or greater) up to the time te when the end of a breath is obtained, is equivalent to the volume A (ml) obtained at the breath-end.
The timing when end of a breath is obtained can be considered to change according to parameters relating to the age, gender, frame etc. of a user to their lung capacity. Thus the breath-end acquisition timing obtained using the above Equation (1) may be corrected using at least one parameter selected from the group of consisting of the age, gender, or frame of the user. The breath-end acquisition timing may also be estimated and determined from at least one parameter from the age, gender, or frame of the user.
Moreover, processing similar to the above may be performed using the output value of the semiconductor gas sensor 14 instead of the output value of the pressure sensor 18, to acquire the breath-end acquisition timing. Moreover, the breath-end acquisition timing may be predetermined. In such cases the processing of step S102 is not required. Note that correction to the breath-end acquisition timing may also be performed in such cases too, using at least one parameter from the age, gender, or frame of the user.
At step 104, determination is made as to whether or not the breath-end acquisition timing that was decided at step S102 has arrived. Processing transitions to step S106 when the breath-end acquisition timing has arrived, and when the breath-end acquisition timing has not yet arrived, standby is maintained until the breath-end acquisition timing arrives. Note that although explanation has been given in the present exemplary embodiment of a case in which determination is made as to whether or not the breath-end acquisition timing as calculated according the Equation (1) has arrived, the output values of the pressure sensor 18 from detection of breath that has been blown thereon may be integrated, and determination may be made that the breath-end acquisition timing has arrived when the integrated value is a predetermined threshold value equivalent to the volume A (ml) to obtain the end of a breath, or greater.
At step S106, the output value of the semiconductor gas sensor 14 is acquired and stored, for example in the RAM 12C. Moreover, the solenoid valve of the fuel cell gas sensor 16 is opened, drawing in the breath, and the output values of the fuel cell gas sensor 16 are drawn in every specific interval and stored, for example in the RAM 12C. Then when a peak value is detected in the output values of the fuel cell gas sensor 16 stored in the RAM 12C, the peak value is stored in the RAM 12C. After which, the output values of the fuel cell gas sensor 16 continue to be acquired and stored in the RAM 12C at every subsequent specific interval.
At step S108, the acetone concentration under the influence of ethanol is acquired that corresponds to the output value of the semiconductor gas sensor 14 acquired at step S106. More specifically, as illustrated in 6, table data T1 expressing correspondence relationships between output values of the semiconductor gas sensor 14 and the acetone concentration under the influence of ethanol is pre-stored in the non-volatile memory 12D. The table data T1 is then employed to acquire the acetone concentration under the influence of ethanol corresponding to the output value of the semiconductor gas sensor 14. This thereby enables the acetone concentration under the influence of ethanol to be acquired that corresponds to the output value of the semiconductor gas sensor 14 at the breath-end acquisition timing. In 6, units of the output value of the semiconductor gas sensor 14 are voltage values (V), however units of resistance values (kΩ), or current values (A) may be employed. This also applies to the other graphs.
An operation formula, such as the following equation representing a correspondence relationship between an output value Ca of the semiconductor gas sensor 14 and an acetone concentration Conc1 under the influence of ethanol, may also be pre-stored in the non-volatile memory 12D, and then the acetone concentration Conc1 that corresponds to the output value Ca of the semiconductor gas sensor 14 calculated using the operation formula. Conc1 = k1 × Ca + k2 Equation (2)
Herein k1 and k2 are predetermined coefficients, and are coefficients obtained as a result of using statistical methods based on pre-measured results of the correspondence relationship between the output value of the semiconductor gas sensor 14 and the acetone concentration. The Equation (2) is a first order equation including the output value Ca of the semiconductor gas sensor 14 as a variable, and including the product of output value Ca of the semiconductor gas sensor 14 and coefficient k1, however a polynomial equation of second order or higher may be employed. An equation including at least one calculation from a reciprocal calculation, an index calculation, or a logarithmic calculation may be employed. The concentration of the acetone under the influence of ethanol may also be considered to vary according to parameters such as the age, gender, and frame of the user. The acetone concentration Conc1 obtained by Equation (2) may accordingly be corrected using at least one parameter from the age, gender, or frame of the user.
At step S110, a provisional ethanol concentration corresponding to the output value (peak value) of the fuel cell gas sensor 16 obtained at step S106 is acquired. More specifically, as illustrated in 7, table data T2 expressing a correspondence relationship between the output value of the fuel cell gas sensor 16 and a provisional ethanol concentration is pre-stored in the non-volatile memory 12D, then the provisional ethanol concentration that corresponds to the output value of the fuel cell gas sensor 16 is acquired using the table data T2. This thereby enables a provisional ethanol concentration to be acquired that corresponds to the output value of the fuel cell gas sensor at the breath-end acquisition timing. In 7, the units of the output value of the fuel cell gas sensor 16 are voltage values (V), however units of current values (A) may be employed. Similar applies to the other graphs.
An operation formula, such as the equation that follows, expressing a correspondence relationship between the output value Cb of the fuel cell gas sensor 16 and the ethanol concentration Conc2 may be pre-stored in the non-volatile memory 12D, and the provisional ethanol concentration Conc2 that corresponds to the output value Cb of the fuel cell gas sensor 16 calculated using this operation formula. Conc2 = k3 × Cb + k4 Equation (3)
Herein, k3 and k4 are predetermined coefficients, and are coefficients obtained as a result of using statistical methods based on pre-measured results of the correspondence relationship between the output value of the fuel cell gas sensor 16 and the provisional ethanol concentration. The Equation (3) is a first order equation including the output value Cb of the fuel cell gas sensor 16 as a variable, and including the product of the output value Cb of the fuel cell gas sensor 16 and coefficient k3, however a polynomial equation of second order or higher may be employed. An equation including at least one calculation from a reciprocal calculation, an index calculation, or a logarithmic calculation may be employed. The provisional ethanol concentration may also be considered to vary according to parameters such as the age, gender, and frame of the user. The provisional ethanol concentration Conc2 obtained by Equation (3) may accordingly be corrected using at least one parameter from the age, gender, and frame of the user.
At step S112, the provisional acetone concentration excluding the influence of ethanol is acquired that corresponds to the output value of the semiconductor gas sensor 14 and the output value of the fuel cell gas sensor 16 acquired at step S106. More specifically, as illustrated in 8, table data T3 expressing correspondence relationships between the output value of the semiconductor gas sensor 14, the output value of the fuel cell gas sensor 16, and the provisional acetone concentration excluding the influence of ethanol is pre-stored in the non-volatile memory 12D. The table data T3 is then employed to acquire the provisional acetone concentration excluding the influence of ethanol that corresponds to the output value of the semiconductor gas sensor 14 and the output value of the fuel cell gas sensor 16. This thereby enables the provisional acetone concentration excluding the influence of ethanol to be acquired that corresponds to the output value of the semiconductor gas sensor 14 and the output value of the fuel cell gas sensor 16 at the breath-end acquisition timing.
An operation formula, such as one expressed by the following equation expressing correspondence relationships between the output value Ca of the semiconductor gas sensor 14, the output value Cb of the fuel cell gas sensor 16, and the provisional acetone concentration Conc3 excluding the influence of ethanol, may be pre-stored in the non-volatile memory 12D. The operation formula may then be employed to calculate the provisional acetone concentration Conc3 excluding the influence of ethanol that corresponds to the output value Ca of the semiconductor gas sensor 14 and the output value Cb of the fuel cell gas sensor 16. Conc3 = k5 × Ca + k6 × Cb + k7 Equation (4)
Herein, k5 to k7 are predetermined coefficients, and are coefficients obtained as a result of using statistical methods based on pre-measured results of the correspondence relationships between the output value of the semiconductor gas sensor 14, the output value of the fuel cell gas sensor 16, and the provisional acetone concentration excluding the influence of ethanol. The Equation (4) is a polynomial equation including the output value Ca of the semiconductor gas sensor 14 and the output value Cb of the fuel cell gas sensor 16 as variables, and including the product of the output value Ca of the semiconductor gas sensor 14 and coefficient k5, and the product of the output value Cb of the fuel cell gas sensor 16 and coefficient k6, however a first order equation, or a polynomial equation of second order or higher, may be employed. An equation including at least one calculation from a reciprocal calculation, an index calculation, or a logarithmic calculation may be employed. The provisional acetone concentration excluding the influence of ethanol may also be considered to vary according to parameters such as the age, gender, and frame of the user. The acetone concentration Conc3 obtained by Equation (4) may accordingly be corrected using at least one parameter from the age, gender, or frame of the user.
As illustrated in 9, table data T4 expressing correspondence relationships between the acetone concentration under the influence of ethanol, the provisional ethanol concentration, and the provisional acetone concentration excluding the influence of ethanol may be pre-stored in the non-volatile memory 12D. The table data T4 may then be employed to acquire the provisional acetone concentration excluding the influence of ethanol that corresponds to the acetone concentration under the influence of ethanol acquired at step S108 and the provisional ethanol concentration acquired at step S110. In such a case too, similarly to Equation (4), an operation formula for calculating the provisional acetone concentration excluding the influence of ethanol using the acetone concentration under the influence of ethanol and the provisional ethanol concentration as variables may be pre-stored in the non-volatile memory 12D. This operation formula may then be employed to calculate the provisional acetone concentration excluding the influence of ethanol.
At step S114, the provisional acetone concentration excluding the influence of ethanol acquired at step S112, and the provisional ethanol concentration acquired at step S110, are displayed on the display section 20.
Displaying the provisional ethanol concentration acquired at this point in time on the display section 20 in this manner enables the user to be prevented from having to wait a long period of time. The provisional acetone concentration and the provisional ethanol concentration have accuracies that are inferior to those of the final acetone concentration and the final ethanol concentration described later, however they are of a usable accuracy. The provisional acetone concentration and the provisional ethanol concentration are particularly close to their respective final concentrations in environments in which ethanol is present at a low concentration.
At step S116, the final ethanol concentration is acquired and displayed on the display section 20. As illustrated in the example in 10, a steady state value St is estimated based on the change in output value of the fuel cell gas sensor 16, and an integrated value is estimated for the output values of the fuel cell gas sensor 16 from when a peak value Pk is reached to returning to the steady state value St. This integrated value represents the final ethanol concentration. The steady state value St is a value in a stable state in which change in the output value of the fuel cell gas sensor 16 is stable, and is a value in a state in which ethanol is not being detected.
More specifically, coefficients a, b are found by substituting peak value Pk (= y1),
time t1 when peak value Pk was acquired, output value y2 acquired at current time t2, and current time t2 in the following Equation (5) that calculates output value y of the fuel cell gas sensor 16 from time t, and solving the following obtained simultaneous equations Equation (6) and Equation (7). y = a × t + b Equation (5) y1 = a × t1 + b Equation (6) y2 = a × t2 + b Equation (7)
Wherein coefficient a expresses the slope of a line connecting (t1, y1) and (t2, y2), and the difference between peak value Pk and steady state value St is expressed by the following equation. Pk – St = a × d Equation (8)
Steady state value St is accordingly expressed by the following equation. St = Pk – (a × d) Equation (9)
Wherein d is a predetermined coefficient for finding steady state value St from the slope (coefficient a) of the line connecting (t1, y1) and (t2, y2), and from peak value Pk, and is a coefficient obtained as a result of using statistical methods based on pre-measured results of the relationships between coefficient a, peak value Pk, and steady state value St.
Thus the steady state value St can be found by substituting the peak value Pk and coefficient a into Equation (9). Steady state value St may be an average value of the output values of the fuel cell gas sensor 16 over a period when the output value of the fuel cell gas sensor 16 was stable prior to time t1 when the peak value Pk was acquired, namely a period when fluctuations in the output value of the fuel cell gas sensor 16 have converged to within a predetermined range.
A time t3 when the steady state value St is found by substituting the obtained steady state value St into Equation (5).
Although the Equation (5) in the present exemplary embodiment is a first order equation, a polynomial equation of second order, or third or higher order may be employed.
Next, as illustrated in 10, the respective output values of the fuel cell gas sensor 16 are calculated using Equation (5) over the period from time t1 when peak value Pk was acquired to time t3 when the steady state value St was obtained, and the integrated value thereof obtained (the integrated value of the region illustrated by diagonal shading in 10). As illustrated in 11, table data T5 expressing correspondence relationships between the integrated value of the output values of the fuel cell gas sensor 16 and the final ethanol concentration is pre-stored in the non-volatile memory 12D, and the table data T5 is employed to acquire the final ethanol concentration corresponding to the integrated value of the output values of the fuel cell gas sensor 16.
An operation formula, such as the equation given below, expressing correspondence relationships between the integrated value H of output values of the fuel cell gas sensor 16 and the final ethanol concentration Conc4 may be pre-stored in the non-volatile memory 12D. Then the final ethanol concentration Conc4 that corresponds to the integrated value H of output values of the fuel cell gas sensor 16 may be calculated using the operation formula. Conc4 = k8 × H + k9 Equation (10)
Herein, k8 and k9 are predetermined coefficients, and are coefficients obtained as a result of using statistical methods based on pre-measured results of the correspondence relationships between the integrated value of the output values of the fuel cell gas sensor 16, and the final ethanol concentration. The Equation (10) is a first order equation including the integrated value H of the output values of the fuel cell gas sensor 16 as a variable, and including the product of the integrated value H of the output values of the fuel cell gas sensor 16 and coefficient k8, however a polynomial equation of second order or higher may be employed. An equation including at least one calculation from a reciprocal calculation, an index calculation, or a logarithmic calculation may be employed. The final ethanol concentration may also be considered to vary according to parameters such as the age, gender, and frame of the user. The final ethanol concentration Conc4 obtained by Equation (10) may accordingly be corrected using at least one parameter from the age, gender, or frame of the user.
Thus the duration to return to the steady state value St is estimated, and the final ethanol concentration is calculated, without waiting until the steady state value St has been reached after acquiring the peak value Pk, thereby enabling the time taken until the final ethanol concentration is displayed to be shortened.
After waiting for the output values of the fuel cell gas sensor 16 to return to the steady state value, an integrated value may be employed that is an integration of the output values of the fuel cell gas sensor 16 actually acquired from time t1 when the peak value Pk was acquired to time t3 to obtain the steady state value, and the final ethanol concentration acquired from table data T5.
At step S117, the final acetone concentration is acquired and displayed on the display section 20. More specifically, as illustrated in 16, table data T8 expressing correspondence relationships between the acetone concentration under the influence of ethanol, the final ethanol concentration, and the final acetone concentration excluding the influence of ethanol is pre-stored in the non-volatile memory 12D. The table data T8 is then employed to acquire the final acetone concentration excluding the influence of ethanol that corresponds to the acetone concentration under the influence of ethanol acquired at step S108 and the final ethanol concentration acquired at step S116.
An operation formula, such as the equation given below, expressing correspondence relationships between the acetone concentration Conc1 under the influence of ethanol, the final ethanol concentration Conc4, and the final acetone concentration Conc5 excluding the influence of ethanol may be pre-stored in the non-volatile memory 12D. The operation formula may then be employed, and the final acetone concentration Conc5 excluding the influence of ethanol calculated that corresponds to the acetone concentration Conc1 under the influence of ethanol acquired at step S108, and the final ethanol concentration Conc4 acquired at step S116. Conc5 = k10 × Conc1 + k11 × Conc4 + k12 Equation (11)
Herein, k10 to k12 are predetermined coefficients, and are coefficients obtained as a result of using statistical methods based on pre-measured results of the correspondence relationships between the acetone concentration under the influence of ethanol, the final ethanol concentration, and the final acetone concentration excluding the influence of ethanol. The Equation (11) is a polynomial equation including the acetone concentration Conc1 under the influence of ethanol and the final ethanol concentration Conc4 as variables, and including the product of the acetone concentration Conc1 under the influence of ethanol and coefficient k10, and the product of the final ethanol concentration Conc4 and coefficient k11, however a first order equation, or a polynomial equation of second order or higher may be employed. An equation including at least one calculation from a reciprocal calculation, an index calculation, or a logarithmic calculation may be employed. The final acetone concentration may also be considered to vary according to parameters such as the age, gender, and frame of the user. The final acetone concentration Conc5 obtained by Equation (11) may accordingly be corrected using at least one parameter from the age, gender, or frame of the user.
At step S118, physical condition risk information is acquired based on the final acetone concentration acquired at step S117, and the final ethanol concentration acquired at step S116. The acquired physical condition risk information is then output to the display section 20 and displayed thereon.
More specifically, as illustrated in 12, table data T6 expressing correspondence relationships between the final acetone concentration, the final ethanol concentration, and physical condition risk information 40 is pre-stored in the non-volatile memory 12D. The table data T6 is then employed to acquire the physical condition risk information 40 that corresponds to the final acetone concentration and the final ethanol concentration.
12 is an example illustrating a case in which the final acetone concentration is classified into 5 levels "low", "normal", "high", "very high", and "too high", and the final ethanol concentration is classified into 5 levels "not present", "slightly present", "present at an alcohol drinking level", "very much present", "excessively present", however there is no limitation to such a method of classification.
The physical condition risk information 40 includes at least one of a physical condition risk level 40A, or advice level information 40B, and both are included in the example of 12. The example in 12 illustrates a case in which the physical condition risk has been classified into 6 levels "physical condition risk level low", and "physical condition risk level 1" to "physical condition risk level 5", however there is no limitation to such a method of classification. The advice level information 40B is advice information that corresponds to the final concentrations of acetone and ethanol, and includes information expressing a physical condition state, and warning information. The area within the intermittent line frame 42 denotes a physical condition target zone. Information indicating specific actions to be taken for recovery may be included within the advice level information 40B.
Acquiring the physical condition risk information from the final acetone concentration and the final ethanol concentration, and displaying the physical condition risk information in this manner enables a user to readily ascertain a physical condition risk from both a fat burn condition and an alcohol consumption condition, enabling recovery to be prompted.
Note that when acquiring the physical condition risk information, the provisional acetone concentration may be employed instead of the final acetone concentration, and the provisional ethanol concentration may be employed instead of the final ethanol concentration.
At step S120, determination is made as to whether or not closing of the cap 10B has been forgotten. More specifically, determination is made as to whether or not there is conduction through the conductive member 34A provided to the main body 10A and the conductive member 34B provided to the cap 10B, and determination is made that closing of the cap 10B has been forgotten when a non-conduction state persists for a predetermined period of time or longer.
When determined that closing of the cap 10B has been forgotten, at step S122 a message is displayed on the display section 20 warning that closing of the cap 10B has been forgotten.
Thus in the present exemplary embodiment, the acetone concentration excluding the influence of ethanol is acquired by using the semiconductor gas sensor 14 having sensitivity to acetone and ethanol and using the fuel cell gas sensor 16 having selective sensitivity to ethanol. This thereby enables the acetone concentration to be detected with good accuracy even under the influence of ethanol.
13 illustrates a graph showing correspondence relationships between concentrations of acetone measured by blowing breath onto a biological gas detection device using a single semiconductor gas sensor as hitherto (sensor converted concentrations), and acetone concentration measured using gas chromatography (gas acetone concentrations) in an environment in which ethanol is present at concentrations from level 1 to level 6 in a low to high concentration range (from 0.5 ppm to 100 ppm).
14 illustrates a graph showing correspondence relationships between final concentrations of acetone measured by blowing breath onto the biological gas detection device 10 according to the present exemplary embodiment that includes the semiconductor gas sensor 14 and the fuel cell gas sensor 16 (sensor converted concentrations), and acetone concentration measured using gas chromatography (gas acetone concentrations) in an environment in which ethanol is present at concentrations from level 1 to level 6 in a low to high concentration range (from 0.5 ppm to 100 ppm).
Whereas the correlation coefficient r between the acetone concentration measured by a biological gas detection device using a single semiconductor gas sensor as hitherto, and the acetone concentration measured using gas chromatography was 0.28 as illustrated in 13, in contrast, the correlation coefficient r between the acetone concentration measured using the biological gas detection device 10 according to the present exemplary embodiment and the acetone concentration measured using gas chromatography was 0.87 as illustrated in 14. Thus since gas chromatography is capable of measuring the acetone concentration with good accuracy, it can be said that the higher the correlation coefficient, the more accurately the acetone concentration can be measured. In the biological gas detection device 10 according to the present exemplary embodiment that includes the semiconductor gas sensor 14 and the fuel cell gas sensor 16, a higher correlation is obtained than for a biological gas detection device using a single semiconductor gas sensor, and so it is apparent that the acetone concentration can be measured with good accuracy.
When acquiring the final acetone concentration excluding the influence of ethanol, for example as illustrated in 15, table data T7 expressing correspondence relationships between the output value of the semiconductor gas sensor 14, the integrated value of the output values of the fuel cell gas sensor 16, and the final acetone concentration excluding the influence of ethanol, may be pre-stored in the non-volatile memory 12D. The table data T7 may then be employed to acquire the final acetone concentration excluding the influence of ethanol that corresponds to the output value of the semiconductor gas sensor 14 acquired at step S106, and to the integrated value of the output values of the fuel cell gas sensor 16 acquired at step S116. In such cases, the final acetone concentration excluding the influence of ethanol may be calculated by using an equation similar to Equation (7) that uses the output value of the semiconductor gas sensor 14 and the integrated value of the output values of the fuel cell gas sensor 16 as variables, and calculates the final acetone concentration excluding the influence of ethanol.
Moreover, in the table data T7 of 15, the acetone concentration under the influence of ethanol may be employed instead of the output value of the semiconductor gas sensor 14, and the final ethanol concentration may be employed instead of the integrated value of the output values of the fuel cell gas sensor 16, and appropriate combinations may be set thereof.
In the table data T3 of 8, the provisional ethanol concentration may be employed instead of the output value of the fuel cell gas sensor 16.
In the table data T4 of 9, an output value of a fuel cell gas sensor may be employed instead of the provisional ethanol concentration.
It is conceivable that when the adsorbent 32 in the cap 10B has adsorbed a lot of gas and the adsorption performance of the adsorbent 32 has fallen, the adsorbent 32 would cease to adsorb gas when the cap 10B was closed, and raising the sensitivity. Thus determination may be made that the time to replace the adsorbent 32 has been reached in cases in which conduction of the cap 10B is detected by detecting conduction of the conductive members 34A, 34B, and gas detected by the semiconductor gas sensor 14 is being detected at a concentration of a predetermined threshold value or greater. A warning message prompting replacement of the adsorbent 32 may then be displayed on the display section 20, or a warning sound prompting replacement of the adsorbent 32 may be emitted.
Moreover, the cap 10B may be configured as a whole from the adsorbent 32, and the whole of the cap 10B replaced each time the replacement time as been reached. Namely, the cap 10B may be configured to be disposable.
The cap 10B may also be coupled to the power switch of the biological gas detection device 10 so as to automatically open and close. Namely, configuration may be made such that the cap 10B opens when the power switch of the biological gas detection device 10 is switched ON, and the cap 10B may be closed when the power switch is switched OFF. This thereby enables forgetting to close the cap 10B after use to be prevented, and enables deterioration of the quality of the semiconductor gas sensor 14 and the fuel cell gas sensor 16 to be prevented.
Moreover, the cap 10B may double as the power switch. Namely, the power of the biological gas detection device 10 may be switched ON when the cap 10B is opened, and the power of the biological gas detection device 10 may be switched OFF when the cap 10B is closed. In such cases a warning message may be displayed on the display section 20, or a warning sound emitted, when a predetermined period of time has elapsed with the cap 10B in a open state.
Configuration may be made such that when the cap 10B is closed, a solenoid valve of the fuel cell gas sensor 16 is actuated, so as to draw cleaning gas into the closed space of the cap 10B and the main body 10A, so as to clean the gas path inside the fuel cell gas sensor 16.
In the present exemplary embodiment, explanation has been given of a case in which acetone is the target gas, however although the concentration of, for example, acetaldehyde gas contained in biological gas of a healthy person is low, the concentration of acetaldehyde is high when there are problems with the liver. Thus the concentration of acetaldehyde gas may be found as the target gas. This thereby enables the condition of the liver to be ascertained.
In the present exemplary embodiment, explanation has been given of a case in which the table data T1 to T7 are pre-stored in the non-volatile memory 12D, however a server may be accessed, such as by Wi-Fi (registered trademark) communication or the like, and the table data T1 to T7 downloaded from the server. A function to read in a memory card may also be provided to the biological gas detection device 10, and the respective table data read in from a memory card on which they are stored.
Bezugszeichenliste

10: biological gas detection device
10A: main body
10B: cap
12: controller
14: semiconductor gas sensor
16: fuel cell gas sensor
18: pressure sensor
20: display section
22: operation section
24: timer
26: communication section
32: adsorbent
34A, 34B: conductive member

ZITATE ENTHALTEN IN DER BESCHREIBUNG
Diese Liste der vom Anmelder aufgeführten Dokumente wurde automatisiert erzeugt und ist ausschließlich zur besseren Information des Lesers aufgenommen. Die Liste ist nicht Bestandteil der deutschen Patent- bzw. Gebrauchsmusteranmeldung. Das DPMA übernimmt keinerlei Haftung für etwaige Fehler oder Auslassungen.
Zitierte Patentliteratur

JP 2007-57392 A [0006]
WO 2012/165182 [0006]

Claims

A biological gas detection device comprising: a semiconductor gas sensor having sensitivity to a target gas and to an interfering gas that are contained in a biological gas; an electrochemical gas sensor having sensitivity to the interfering gas contained in the biological gas; a target gas concentration acquisition means for acquiring a concentration of the target gas based on an output value of the semiconductor gas sensor and an output value of the electrochemical gas sensor; and an output means for outputting information according to the concentration of the target gas.
The biological gas detection device of claim 1, further comprising a pressure sensor that detects a pressure of breath, wherein the target gas concentration acquisition means acquires the concentration of the target gas, under the influence of the interfering gas, which corresponds to the output value of the semiconductor gas sensor at a breath-end acquisition timing determined based on the output value of the pressure sensor.
The biological gas detection device of claim 1, further comprising: a pressure sensor that detects a pressure of breath; and an interfering gas provisional concentration acquisition means for acquiring a provisional concentration of the interfering gas, which corresponds to the output value of the electrochemical gas sensor at a breath-end acquisition timing determined based on the output value of the pressure sensor.
The biological gas detection device of claim 3, wherein the output means outputs a provisional concentration of the interfering gas to a display means after the provisional concentration of the interfering gas has been acquired.
The biological gas detection device of any one of claim 1 to claim 4, wherein the target gas concentration acquisition means acquires a provisional concentration of the target gas being excluded of influence of the interfering gas, which corresponds to the output value of the semiconductor gas sensor and the output value of the electrochemical gas sensor.
The biological gas detection device of claim 5, wherein the output means outputs a provisional concentration of the target gas to a display means after the provisional concentration of the target gas has been acquired.
The biological gas detection device of any one of claim 1 to claim 6, further comprising an interfering gas final concentration acquisition means for acquiring a final concentration of the interfering gas, which corresponds to an integrated value of the output values of the electrochemical gas sensor from a time at which the output value of the electrochemical gas sensor has reached a peak value to a time at which the output value has returned to a steady-state value.
The biological gas detection device of claim 7, further comprising an estimating means for estimating the steady-state value based on a change in the output value of the electrochemical gas sensor, wherein the interfering gas final concentration acquisition means acquires the final concentration of the interfering gas based on the steady-state value estimated by the estimating means.
The biological gas detection device of claim 7 or claim 8, wherein the target gas concentration acquisition means acquires a final concentration of the target gas based on the concentration of the target gas under the influence of the interfering gas and based on the final concentration of the interfering gas.
The biological gas detection device of any one of claim 1 to claim 9, further comprising a physical condition risk information acquisition means for acquiring physical condition risk information, related to a degree of physical condition risk, based on the concentration of the target gas and the concentration of the interfering gas, wherein the output means outputs the physical condition risk information.
The biological gas detection device of claim 10, wherein the physical condition risk information includes at least one from a physical condition risk level, or advice information that corresponds to the concentration of the target gas and to the concentration of the interfering gas.
The biological gas detection device of any one of claim 1 to claim 11, further comprising a cap that covers an air intake into which the biological gas is blown, and an adsorbent that adsorbs a contaminating substance that contaminates at least one of the semiconductor gas sensor and the electrochemical gas sensor.
The biological gas detection device of claim 12, further comprising: a detection means for detecting whether the cap is open or closed; and a warning means for warning that the adsorbent should be replaced when the output value of the semiconductor gas sensor has reached a predetermined threshold value or greater in a closed state of the cap.
The biological gas detection device of claim 12 or claim 13, wherein opening and closing the cap also functions to switch a power switch ON or OFF.
The biological gas detection device of any one of claim 12 to claim 14, further comprising an alert means for alerting when a predetermined period of time has elapsed in an opened state of the cap.
The biological gas detection device of any one of claim 1 to claim 15, wherein the target gas is acetone or acetaldehyde, and the interfering gas is ethanol.
A biological gas detection method comprising: based on an output value of a semiconductor gas sensor having sensitivity to a target gas and to an interfering gas that are contained in a biological gas, and based on an output value of an electrochemical gas sensor having sensitivity to the interfering gas contained in the biological gas, acquiring a concentration of the target gas; and outputting information according to the concentration of the target gas.
A biological gas detection program that causes a computer to execute processing, the processing comprising: based on an output value of a semiconductor gas sensor having sensitivity to a target gas and to an interfering gas that are contained in a biological gas, and based on an output value of an electrochemical gas sensor having sensitivity to the interfering gas contained in the biological gas, acquiring a concentration of the target gas; and outputting information according to the concentration of the target gas.