WO2000065334A1

WO2000065334A1 - Exhaled gas detecting method and device therefor

Info

Publication number: WO2000065334A1
Application number: PCT/JP2000/002714
Authority: WO
Inventors: Mitsuharu Kira; Junko Yanagidani; Nobuaki Murakami; Takashi Matsumoto
Original assignee: Fis Inc.
Priority date: 1999-04-27
Filing date: 2000-04-26
Publication date: 2000-11-02
Also published as: TW548092B; JP4477780B2; AU4142300A

Abstract

A gas detecting method and a device therefor, wherein the time needed from the time the power is turned on till gas detection becomes possible is short. A microcomputer (5) delivers a pulse signal to cause the on-duty of a transistor (Q1) to be 75 ν sec from an exhaled gas detection to reduce the average voltage to be applied to a heater (2) and causes the temperature of a metal oxide semiconductor gas sensor (3) to shift to a lower-temperature heating state. The resistance value of a gas sensor sampled at the point of time this shifting is started is stored in a built-in RAM as a reference resistance value RO', and ratios Rs/RO' are computed where Rs is a resistance value found by sampling thereafter every 0.5 sec. And the ratio of the calculated value obtained 2 sec after the start of low temperature heating state shift, to the reference value (Rs/RO) found in the adjustment mode is found, on the basis of which ratio the degree of halitosis is determined and a character corresponding to the determined degree of halitosis is displayed on an LCD (4).

Description

Description: Expired gas detection method and device

TECHNICAL FIELD The present invention relates to a breath gas detection method for detecting alcohol components and a bad breath factor gas component, and a device therefor. Background art

In a conventional portable gas detector using a metal oxide semiconductor gas sensor, it is necessary to wait until the sensor output signal becomes stable after the power is turned on (initial function), that is, from several ten seconds to several minutes. was there. Immediately after the injection, a high temperature is applied to the heater of the acid gas sensor to create a high temperature state to clean the sensor surface and stabilize the sensor output signal faster (heat cleaning). It took several 10 seconds to perform The waiting time is long; the reason for this is that it is necessary to wait for the initial action ゃ sensor after heat cleaning to stabilize the value drift, and then measure it in the gas and further . At the age of exposure to gas without waiting for the sensor to stabilize after heat cleaning, the sensibility of the resistance value in the detected gas became very poor. In addition, the longer the time required for detection, the greater the power consumption. In particular, when using a battery as a battery, there was no way to detect several 10 times: ^.

In addition, most metal oxide ^^ body gas sensors fluctuate the gas sensitivity and the resistance value in the gas due to interference by gas components that are not to be detected, and it is not easy to obtain a means to correct the fluctuation. , Not enough accuracy; ^ could not be obtained.

By the way, the bad breath checker using the gas detection method described above (Refer to Japanese Utility Model Application Laid-Open No. 644-2420.) As mentioned above, it takes time s from detection of impact to detection, and the resistance of gas in gas is ^ m. Also, there was a P theme that accuracy deteriorated due to the influence of the atmosphere. ; Disclosure of the invention

The present invention has been made in view of the following points. The purpose of the present invention is to achieve high reproducibility, high accuracy, and high efficiency even if the time from input to gas detection is shortened. Is to use a small expiration gas detection method. That is, the expiration gas detection method of the present invention starts the energization of the ^ J1 oxide gas sensor and generates high ^] D heat according to the operation start signal, and exhales the high oxygen gas gas during the high D heat. Spraying is performed based on a change in the resistance value of the metal oxide semiconductor gas sensor caused by the expiration of the exhaled gas, and the height of the oxide semiconductor gas sensor is stopped based on this detection to reduce the flow rate. After being in the low state, the resistance value of the oxide gas sensor at the time of Si § Si§ is detected, and based on the detected value, the temperature of the gas during exhalation is detected. It is characterized by the detection of the gas components.

In this exhaled gas detection method, the gas component is heated to a temperature higher than that of the metal oxide semiconductor gas sensor before being turned on. As a result, gas can be detected in a short time from the start of energization, and the change of the observation value when exhaled air is blown into the oxygen semiconductor gas sensor under high temperature conditions is changed to {b}. As a trigger for the timing of the generation of gas, it is easy to determine the timing of the transition to the low state, and the time from the expiration of the exhalation to the time of obtaining the response of the body oxide sensor can be shortened, and the state can be further increased After exposing with

Since the value after one temple period has been detected since then, Even if there is, it is possible to detect with very good alertness and high accuracy, and furthermore, the shorter the recognizing time is, the lower the consumption is, the age of ¾, and the length of m¾ is inversely longer. There is an effect that can be.

According to the above-mentioned method for detecting exhaled gas, the resistance value was determined immediately before or after the detection of exhaled breath under high temperature heating conditions, and the resistance value was calculated based on the withdrawal value.

It is preferable to detect a gas component of interest in tine exhalation by comparing the value of the ratio with the ffjfESmffi resistance value with the value of a preset reference ratio. As for this ^, it is possible to cancel the fluctuation component equivalent to the high-temperature state and high-precision detection is possible.

In the above-mentioned exhaled gas detection method,

^ ΠΒ ^ Shading object ^ It is preferable to detect with the resistance of the body sensor. This: ^ can quickly detect the expiration in fit ^.

Further, in the above-described exhaled gas detection method, it is preferable that the expiration of the exhaled gas is detected by a resistance of a fiJlE ^ S acid sensor based on a change in a gas component in the exhaled gas. In this case also, expiration blowing can be detected quickly and reliably.

In the above-described exhaled gas detection method, it is preferable that the predetermined time elapse is within a period before the resistance of the firf metal semiconductor gas sensor is stabilized. Thereby, the time until the detection can be further shortened.

In the above-described exhaled gas detection method, the gas component to be detected is preferably alcohol. This ^ can perform the alcohol detection;

In the above-described exhaled gas detection method, the gas component to be detected is preferably a bad breath-causing gas component. This ^^ can be a mouth ^^ method that produces the effects of the invention described above. It is a further object of the present invention to provide a breath gas detection device which has a high accuracy even when the time from gas introduction to gas detection is shortened 14 and which has high accuracy and small power consumption. That is, the expiration gas detection device of the present invention comprises an oxide gas sensor, a heater for powering the oxygen gas sensor, and an operation signal.

The energization of the tin heater is controlled so that the temperature of the body gas sensor becomes high, and under the high temperature condition, the expiration of the exhaled gas is detected by the oxygen gas sensor based on the change in the resistance value of the tut oxygen sensor. Then, based on the detection, the heater control means for controlling the energization of the self-heater so that the temperature of the gas sensor becomes low, the power of the gas sensor for the sulfur gas, and the temperature and temperature of the gas sensor for the ^ fS acid gas. At the time of the start of the energization control of the heater itself, the resistance value of the oxide gas sensor is detected at the point of time 寺, and during the expiration, the resistance value of the oxide gas sensor is detected based on the fiber resistance value. And a detecting means for detecting a gas component of the contained intellectual fiber.

In the exhaled gas detector with the above 13 composition, the gas component is made to go to the metal oxide semiconductor gas sensor at high temperature and then to the i & mid K state. The response of the sensor resistance can be made to appear between the temples.As a result, gas detection can be performed in a short time from the start of electricity supply. Since the change is used as a trigger for the opening and closing of the state, the timing of the opening of the state can be easily determined, and the time from the expiration of the expiration to the time when the response of the body gas sensor from the patient is obtained is increased. short can, after exposure to breath even higher state, Le detects the resistance value after between one ^ after low state ^^ ^1, because, even within between over between when short于後Very reproducible and highly accurate detection, and detection time Shorter has the effect that the consumption is small and the life of ^^, where n is a pond, can be extended in inverse proportion. In the above-mentioned exhaled gas detector, the resistance value immediately before or after detection of exhaled breath under high temperature heating condition is regarded as resistance, and ϋίΙΕ ^ oxidation at a certain time from the mouth! ^ State 亍By comparing the ratio of the resistance value of the object-body gas sensor to the filfES ^^ value and the value of the preset reference ratio, it is possible to detect the gas component of the nervous exhalation that is to be detected. preferable. In addition to the effects of the above-described invention, the fluctuation component equivalent to the high-temperature state and the dedication can be canceled, and high-precision detection becomes possible.

It is preferable that the expiration gas is detected with the above-described exhaled gas detection device by using an excimer acid sensor of the exhalation gas sensor. In this case, the expiration of expiration can be detected quickly and accurately.

Further, in the above-mentioned exhaled gas detection device, it is preferable that the expiration of the exhaled gas is detected by a fiber sensor of an oxide sensor based on a gas component and a change in the exhaled gas. In this case also, expiration of expiration can be detected quickly and reliably.

In the above-mentioned exhaled gas detection device, it is preferable that the reversal point for a certain period of time is within a certain period before the resistance of the metal oxide semiconductor gas sensor is stabilized. This has the effect of shortening the time until detection.

In the above-described exhaled gas detection apparatus, the gas component to be detected is preferably alcohol. This ^ can provide an alcohol detection device having the effects of the above-described invention.

In the above-mentioned expired gas detection device, it is preferable that the gas component to be detected is a bad breath factor gas. This: ^ can be a mouth: ^ sensing device that has the effect of the invention described above.

In the case of the above-mentioned exhaled gas detector, if the value of the high-fiber fiber ftrlE oxide semiconductor gas sensor is in the upward direction due to a predetermined transversion or exhalation blow, In this case, it is preferable to determine that it is inactive. This can be prevented from being noticed by the contamination of the detection atmosphere.

Further features of the present invention and the effects provided thereby will be understood from the following detailed description of the invention and examples thereof, with reference to the accompanying drawings. Brief description of the drawings

FIG. 1 is a specific circuit diagram of an embodiment of the breath detection device of the present invention.

FIG. 2 is a timing chart for explaining the operation of the above air pollution detection.

FIG. 3 is a timing chart for explaining the operation of the ^ M Hb #) body gas sensor when there is no bad breath in the above-mentioned bad breath factor gas detection.

Fig. 4 is a timing chart for explaining the operation of the metal oxide gas sensor when there is bad breath in the above-mentioned bad breath factor gas detection.

FIG. 5 is a timing chart for explaining the operation of the metal oxide gas sensor at the time of alcohol synthesis in the alcohol detection.

FIG. 6 is a timing chart for operation of the metal oxide semiconductor semiconductor gas sensor when an alcohol component is present in the alcohol detection. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the present embodiment, an exhaled gas detector, for example, a gas detector constituting a bad breath checker is configured, and FIG. 1 shows a circuit diagram of the embodiment.

In this embodiment, a low-voltage (for example, '3 V) battery 1 such as a dry cell or a rechargeable battery and a heater 2 are embedded in a gas-sensitive body for detecting gas, and both ends of the heater 2 2) and the output of the gas sensor connected to one end of the gas-sensing body 1) 3) a highly-structured heat-responsive acid gas sensor 3 and a liquid crystal table (hereinafter referred to as LCD and ^). 4) The means for passing through the heater 2 and the means for detecting the carried fiber gas are programmed and the LCD 4 is equipped with a dry function. The main components are a microcomputer (hereinafter abbreviated as “microcomputer”) 5 that performs processing, and an EEPROM 6 that is data used as a reference for determining the degree of bad breath.

The metal oxide gas sensor 3 has a resistance value between the output rice cake and the ground end of the heater 2 ′ ^^ KD. The heater 2 is connected via a PNP transistor Q1. In addition, the gas-sensitive body is connected via a parallel circuit of a series circuit of PN p-type transistors Q2 and 2 and a series circuit of PNP-type transistor Q3 and a resistor R9. When the transistor Q2 or Q3 or both are on, the voltage VS across the gas-sensitive body is generated by the current flowing through the resistor R2 or R9 or the parallel circuit of both resistors.

The microcomputer 5 calculates the resistance value of the gas sensing material at both ends ¾EV s.

The microcomputer 5 receives the power by connecting the power supply J terminal V to the battery power supply 1 via the diode D 1, and connects the middle point of the series circuit of the start switch SW and the resistor R 5 indicated by the arrow to the input port I 2. When the input port I2 goes high (hereinafter referred to as H level), control processing for gas detection is started according to the program.

Further, the microcomputer 5 sets the midpoint to the base of the transistor Q1, and connects the other end of the series circuit of the resistors R3 and R4, one end of which is connected to the positive pole of the power supply 1, to the output port Ο1. Output port O Outputs a panless signal for duty control. A function is provided to turn on the heater 2 by turning on and off the star Q1, and by using this function, the on-duty of the transistor Q1 is extended to force the metal oxide semiconductor gas sensor 3 to a high-temperature state or, conversely, to shorten it. By doing so, the heating control to be in the inactive state is performed.

Further, the microcomputer 5 outputs the bias circuit of the transistor Q2 as an output port.

By connecting the bias circuit of the transistor Q3 to the output port 04 and setting the output ports 03 and O4 to low level, the base current flows to the corresponding transistors Q2 and Q3 to turn them on. The resistances R 2 and R 9 are connected between the resistance R s and the positive pole of 1. In other words, it has the ability to switch the load resistance. ,

Further, the microcomputer 5 assigns the input terminals ID1 to ID4 of the LCD 4 to the output ports Ol1 to 014, the input ID5 and ID6 to the output port Ol5, and the input terminal I to the output port Ol6. Input D7 and ID8 to output port Ol 7 ^? "ID9 and ID10, and output port Ol 8 to input ^ ID11 and ID12, and output port Ol9 to input terminals ID13 and ID14 and output Port O 20 has inputs ^ ID 15 and ID 16, respectively, and has a common channel of 04. Ml is converted to output port O 2 and output from output ports Ol 1 to 020 and 02. The character display of L CD 4 is now controlled.

Also, the microcomputer 5 takes in the voltage of the shunt regulator 7 into the input port I3, and when the voltage of the shunt regulator 7 becomes lower than a predetermined value, the microcomputer 5 detects that the shunt has run out. ^.

The shunt regulator 7 is adapted to stabilize the rnmmiE to a predetermined ma, being disliked by the pond irni via the transistor Q2 and the resistor R1.

The EEPROM 6 is used for registering a reference for detecting a gas detected by a known method. During the inspection process of the apparatus, the semiconductor gas sensor under high temperature conditions is used. The value of i¾¾R 0 of the gas sensing element of (3) and the value of ¾¾tR s (^ and the ratio R s / RO of the two when switching from high temperature to low The value of the ratio is used as a basis for the detection of bad breath gas (eg, carbon, carbon, ammonia, or methyl menolecabutane), ie, the detection of mouth-to-mouth. In this way, it is possible to set an appropriate basic simple R s / R 0 in consideration of the variation of the ^ M oxide semiconductor gas sensor 3.

The EEPROM 6 connects the data input DI, the serial clock terminal SR, and the chip selector terminal CS to the data output port do, output ports 021, 〇22 of the microcomputer 5, respectively, and pulls up with the resistors R7, R8, R6 respectively. ing. The data output terminal DO is connected to the data input terminal di of the microcomputer 5.

Input 04 is input 101 to 1016 and communication l COM1 is boosted by a resistor, respectively. Common »COM 1 and input terminal ID of any input corresponding to the character:! In this case, the characters corresponding to this word are displayed, and ID1 to ID4 correspond to the concentration of the bad breath factor gas, that is, the degree of bad breath, respectively, to the ^ "character, and ID5 to ID5. ID16 corresponds to a character such as a person displayed on both sides of the character indicating the observation, and if the concentration of the bad breath gas increases, the wheat It becomes steep.

Note that in the figure, number 8 is a reset IC that gives a reset signal to microcomputer 5 when power is turned on to reset it, number 9 is a reference clock to the microcomputer, and # 10 is a clock generation circuit. Connector. C1 to C3 are capacitors.

Next, the operation of this embodiment will be described. First, when mi i is reset, the microcomputer 5 is reset by reset I C8i t!) And the right is set. Thereafter, the microcomputer 5 operates in the low-consumption mode to be in a state. In this state, the setting for the output port 03 of the microcomputer 5? "When the start switch SW is turned on with the connection between the ADJ and the ground, the microcomputer 5 rises to the input level of the input port I2, that is, when the operation start signal is input, the microcomputer 5 The operation state of the pre-programmed mode is entered, and a pulse signal is generated from the output port Ol with a period of, for example, 8.2 msec and a low voltage period of 96 μs.

Therefore, the transistor Q1 is turned on and off with a duty of 9600 μsec and a period of 8.2 mssec, and the heater 2 is supplied with an easy-going power during the ON period. At this time, the flat voltage applied to the heater 2 becomes approximately 1 OV by the duty control, so that the amount of heat in the heater 2 is large, and the acid gas sensor 3 is heated to a high temperature state.

On the other hand, the microcomputer 5 outputs a signal to turn on the transistors Q2 and Q3 (or only Q2 or Q3) in synchronization with the off period of the transistor Q1.

3 and 04 (or 〇3 or Ο4), and a parallel circuit (or R9) consisting of resistors R2 and R9, which are loads 負荷, is connected in series to the gas-sensitive material of the oxide semiconductor gas sensor 3. The gas-sensitive body is energized through this load resistance.

Then, after the heating to the high temperature state starts, the resistance value of the gas-sensitive body of the metal oxide semiconductor gas sensor 3 becomes stable. After that, the microcomputer 5 outputs a low signal from the output port # 1. The level period is switched to 75 µsec, and the on-duty of the transistor Q1 is set to 75 µsec while maintaining the cycle. As a result, the average applied to the heater 2 through the transistor Q1 is reduced to approximately 0.3 V, and the amount of the heater 2 is reduced. Therefore, the dormitory-body gas sensor 3 is opened from the high temperature state.

Now, when switching from the high temperature state to the low temperature tl state, and when the transistor Q1 is turned off, the microcomputer 5 is at the right time. Both ends of the gas sensing element of sensor 3 Ξ Ξ V s are taken into input port I 1, and the sensed SEV S and load resistance and value are used to calculate the gas sensing element base of oxygen gas sensor 3 ¾5 resistance R Calculate 0.

Then, during the transition from the start of the low heat state [1] to the thermal state until the resistance value of the metal oxide gas sensor 3 becomes stable, for example, at 2 secm and at the timing when the transistor Q1 is turned off, the microcomputer 5 starts to operate at a low temperature. The voltage between both ends of the gas sensor of the gas sensor 3 is input to the input port I1, and the value R s of the gas sensor of the oxide gas sensor 3 is obtained from the input voltage, load resistance, and easy value. Then, calculate the ratio R s / R 0 between this ¾ ^ value R s and the above-mentioned approximate pile value R 0, and calculate the direct data with R s and RO COf directly as £ £

Nya ^ 1 ~ As a result, a standard for detecting the concentration of the bad breath factor gas component, which is the gas to be detected by the check force, is set.

When the above adjustment mode ends, the microcomputer 5 returns to the state. Then, after the connection between the adjustment terminal ADJ and the ground is released, if the start switch SW1 is turned off, the microcomputer 5 will open the communication mode.

Next, a description will be given of the operation of the present embodiment in which the basic data of ± 3ί is applied to E EPΟΜRΟΜ6 to be actually ^ ffl: ^ for the bad breath check.

It is assumed that the microcomputer has already been turned on and the microcomputer 5 is in the state of power s. In this state, when the start switch SW is turned on and the input port I 2 rises to a high level, the microcomputer 5 is turned on after the conversion processing. The operation in the mode is started, and the data is read out to the EEPROM 6 first, stored in the built-in RAM, and the base used for detecting the degree of bad breath is set.

Also, when the operation mode is started, as in the adjustment mode, the microcomputer 5 sets the period from the output port O1 to 8.2 msec and the low level period to 960 μs. Generate an ec pulse signal.

Therefore, the transistor Q1 is turned on and off with a duty cycle of 960 μsec and a period of 8.2 msec, and during the ON period, the heater 2 of the body gas sensor 3 receives a signal from the heater 1 from the switch 1, As in the case of ± 3ί, the oxygen gas sensor 3 is brought to a high temperature state. For example, the microcomputer 5 samples the voltage between both ends of the gas sensing body at the timing of turning off the transistor Q 1 every 0.5 sec, calculates the resistance value R s of the gas sensing body, and calculates the resistance obtained by the current sampling. The ratio between the value R s and the resistance value R _S obtained by the previous sampling is calculated every 0.5 sec.

When a person to be detected blows expiration on the metal oxide semiconductor gas sensor 3 in a high temperature state, the expiration contains water vapor and gas components, so that the resistance value R s of the gas sensing body decreases, When the ratio of the resistance R s obtained in the current sampling obtained every 0.5 sec to the R _S obtained in the previous sampling is 0.96 or less, the microcomputer 5 detects that expiration has been blown.

Here, the microcomputer 5 detects and determines the pollution of the atmosphere (air pollution) immediately after the above-described breath detection, and interrupts the breathing operation when it determines that the atmosphere is polluted. That is, as shown in FIG. 2, the resistance value Rs of the gas-sensitive body of the metal oxide semiconductor gas sensor 3 detected at the sampling immediately after the exhalation detection opening point ta and the resistance value Rs detected in the adjustment mode and contained in the EEPROM 6 ^ Calculate the ratio of {5} value to R 0, and the obtained value is smaller than a predetermined value (for example, 0.2):: ^ is increasing, that is, the cleaning direction in which 清浄 value R s increases The microcomputer 5 stops the detection operation and returns to the state, judging that the age is in a polluted state where it is impossible to detect bad breath, and displays on the LCD 4 that the air pollution is present. Let it. Fig. 2 shows a diagram of this air pollution judgment, in which the curves A, A, and R show the change in R s R R 0 from the timing ta of the air pollution level and the age call timing. B shows the change of RsZRO in the air pollution state, and C shows that the air pollution was higher and the expiration was blown. Thus, the value of RsZRO indicates the direction of cleanliness, _α indicates the expiration detection limit, and β indicates the air pollution and intellectual limit point.

For good atmospheric pollution, the microcomputer 5 must be able to use the known signal for 1 se, for example, at the time of the call. At the time point, the microcomputer 5 outputs the noiseless signal with the on-duty of the transistor Q1 at 75 μsec while maintaining the period. The output from Ol is set to the low state of the metal gas sensor 3.

The resistance value of the gas-sensitive material sampled at this opening point is stored in the built-in RAM as a resistance value R0, and the ratio with the resistance value Rs obtained by sampling every 0.5 sec thereafter. Operate R s ZR 0 '. Then, the ratio of the calculated value 2 seconds after the start of the state tree to the base f (R s / R 0) obtained in the adjustment mode is obtained, and the degree of bad breath is determined directly from the ratio. The character corresponding to the bad breath degree is displayed on the LCD4. After a certain period of time, the microcomputer 5 returns to the ^ state, and the display of LCD 4 is also turned off.

FIGS. 3 and 4 show the state of Rs R0 (or RsZRO ') from the time point t1 when the start switch SW operates, from the high-temperature state to the time point 13 when the switch is in the ΛδΛ state. Is based on R0 obtained in the I ^ mode, and after time t3, the reference ¾¾t value R0 'obtained at time t3 is used. Figure 3 shows that the value of R s / RO 'obtained at the time t 3 force, 2 sec ¾i§B temple point t 4 is 25, and Figure 4 shows that the time t 3 is 2 sec ¾1 time t It shows that the value of R s / RO 'obtained in 4 is 8.

The base within 8 \ ££? 1 ^ 01 ^ 6 in Figs. 3 and 4! ^ (Direct 1 ^ 5 _/ / 10 is 10 and the value of R s / RO 'obtained at time t 4 is As shown in Fig. 3, it is judged that there is no bad breath when the value is larger than 10 and the value of ^ is less than 10, and it is judged that there is bad breath when it is smaller than 10 as shown in Fig. 4.The microcomputer 5 further calculates the degree of bad breath. Based on the calculated value RsZRO 'and the base value RsZRO, calculate the value and display the character corresponding to the bad breath level on the LCD4 Let it do. No bad breath,: ^ displays the corresponding character on LCD 4.

In FIGS. 3 and 4, t2 indicates the time of call notification. By the way, the microcomputer 5 always checks the value of the shunt regulator 7 and judges that the battery has run out if the value falls below a predetermined value. ? Display til out.

Although the above-described embodiment constitutes a bad breath checker, it can be used as an alcohol check force for measuring blood alcohol concentration.

The alcohol concentration in the blood can be detected by using the fact that the ingested alcohol dissolves in the liquid and the alcohol component is contained in the breath via the lungs. At this age, the oxygen gas sensor 3 sets the resistance value to the value suitable for alcohol detection, and sets the base value (R s

ZR 0), the measurement frequency (R s ZR 0,), and the ratio may be programmed in advance.

This is also awake mode, where the base (R s / RO) and the respective values R s, R 0 are registered in the EEPROM 6, and normally, like the bad breath checker, after the start switch SW is activated, Fiber and air pollution, switching of the gas sensor 3 from high temperature to low temperature, measurement of the base pile value R 0 ', measurement of R s ZR 0' after one temple Then, the blood alcohol level is detected by comparison with the reference R s ZR 0.

Fig. 5, Fig. 6 ίΛ¾ Transition of R s / R 0 under high temperature condition and R s R R 0 after transition to low temperature condition when alcohol check during expiration was performed before and 25 minutes after drinking 'Is shown. In the alcohol check: ^ control the ΡδβΡ state ^^ 亍 at the timing t3, approximately 2 se C after the timing of the notification t2, and measure the base S resistance R0. I have. Then, at time t4 about 2 seconds after this tree, the measurement of Rs / R0 'is compared with the reference Rs / R0 to determine the degree of alcohol tolerance. In Fig. 5, the reference straight line R s ZR O is 2, whereas Therefore, the value of R s / R 0, is very large at 10, and it is determined that this alcohol is not present during exhalation, and the corresponding character is displayed on LCD4. On the other hand, in FIG. 6, the value of R sZRO 'is as small as 1.5, whereas the basic R s / RO is 2, and it is determined that: The blood alcohol concentration is calculated from the value and the strength of the bachelor and the strength, and the corresponding character is displayed on the LCD 4 based on the calculation result. Tl in FIGS. 5 and 6 indicates the timing at which the start switch SW is operated.

In the above embodiment, the presence / absence and concentration of the target gas are determined by comparing RsZRO ′ and the residual RsZRO, but the detection resistance value Rs of the metal oxide based gas sensor ³ and the reference resistance It may be done by comparing with the value. In addition, in the actual inflated condition, the value after a period of detection of the expiration of the expiratory blowing force under the high birth condition is used as the base m¾¾t value R0 '. The resistance value obtained by sampling immediately before detection may be used. Especially high sensitive gas (eg alcohol) and high concentration gas even at high temperature! I know: ^ is power.

Claims

The scope of the claims

1. When the energization signal is turned on, the metal oxide gas sensor starts energizing and heats up, and heat is exhaled. During the high heat, expiration is blown to the ^ oxide gas sensor, which is generated by the expiration. The expiration of the exhaled gas is detected based on the change in the value of the metal oxide sensor ^ body gas sensor, and based on this detection, the high heat of the oxide gas sensor is stopped and the state is turned off. The resistance value of the acid gas sensor at a certain time after the return to the state 1 is detected, and the gas component of the inhaled gas is detected based on the detected resistance. Breath gas detection style with the number of glues as detection

2. The resistance value immediately before or one hour after the detection of expiration under high-temperature conditions is taken as the reference resistance value, from low fiber state ^? To one temple; tins oxide ^^ body gas sensor at ί¾§ The detection of the known gas component in the exhalation of tins by comparing the value of the ratio between the measured value and the ^ TIBS ^ S resistance value with the value of the preset reference ratio is defined as a tree. The exhaled gas detection method according to claim 1.

3. The exhaled gas detection method according to claim 1, wherein the number of glues is that the expiration of exhalation is detected by resistance of the self-acid sensor due to a change in the amount of glue.

4. The expiratory gas detection method according to claim 1, wherein the number of glues is used to detect the expiration of the expiration by the isiititt of the flit self-metal oxide sensor according to the change in the gas component and the change in the expiration. Knowledge method.

5. The exhaled gas detection method according to claim 1, wherein the time point of elapse of time between atns is within a period before the resistance of the metal oxide semiconductor gas sensor is stabilized. '

6. tiife ^ knowledge ¾ · ^ is a teaching that the gas component is alcohol. 1 Expected gas detection method of isife ^>

7. The expiratory gas detection of 1) is described in claim 1 wherein the gas component of the touch is known to be a bad breath factor gas component.

8. Acid and body gas sensor,

A heater for heating the oxide gas sensor;

When the operation is started, the tins heater is controlled to energize the tins heater so that the temperature of the ttns metal oxide gas sensor becomes high while passing through the ttif metal oxide gas sensor.

Heater control means for detecting the blowing of exhaled air on the semiconductor gas sensor, and controlling the energization of the heater based on the detection so that the temperature of the metal oxide semiconductor gas sensor becomes low.

filfS metal oxide ^ よう so that the temperature of the body gas sensor becomes low. 一 One time after the heater energization control is started; A respiratory gas detecting device, comprising: detecting means for detecting a resistance value and detecting a known gas component contained in exhaled breath based on the detected value.

9. Under the high temperature heating condition, the resistance value immediately before or after the detection of expiration is set as the reference resistance value, and the acid value from the low ^^^^^^^ T to the time of one tera thigh b) Body gas sensor 9. The method according to claim 8, wherein the detection of the gas component of "¾" in the expiration is performed by comparing the value of the ratio of the の value and the resistance value with the 基準 value of a preset reference. Exhaled gas detector.

10. The expiration gas detection device according to claim 8, wherein the number of pastes is such that the expiration of expiration is detected by a change in the resistance value of the ftriE ^ oxide ^ solid-state sensor due to the change.

1 1. The exhaled breath gas of claim 8 wherein the number of glues is used to detect the exhalation of the exhaled breath with the resistance of the itnE metal oxide semiconductor sensor based on the gas component and change in the exhaled breath.

12. The expiration gas detection device according to claim 8, wherein the time point of the passage between the one period is within a period before the resistance of the metal oxide semiconductor gas sensor is stabilized.

1 3. Claim 8 that the gas component of fiJlE ^ is alcohol The f¾fe exhalation gas detector

1 4. The expiratory gas detection device So according to claim 8, wherein the gas component of ¾ ¾ is a bad breath factor gas.

1 5. The method according to claim 1, wherein the value of the metal oxide semiconductor gas sensor in a high-temperature state is determined to be out of a predetermined range or to be in an upward direction due to expiration blowout and to be in an inactive state. 8 ΙΞ¾ 呼 expiratory gas detector go