JP2013246007A - Exhalation sensor and alcohol concentration measuring device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhalation sensor that measures a flow rate, a temperature and humidity of exhalation by using a single-element sensor to determine whether it is exhalation of a person or not, and an alcohol concentration measuring device using the same.SOLUTION: An exhalation sensor includes: a first temperature-sensitive resistor 31 and second temperature-sensitive resistor 32 that are provided on one semiconductor substrate 2 and arranged in an exhalation flow path; a first circuit that controls the first temperature-sensitive resistor to be at a first temperature and outputs the amount of power corresponding to power consumption for maintaining it at the temperature; a second circuit that controls the first temperature-sensitive resistor to be at a second temperature and outputs the amount of power corresponding to power consumption for maintaining it at the temperature; a third circuit that outputs the amount of power corresponding to a resistor value of the second temperature-sensitive resistor having almost the same temperature as a gas to be inspected; and a fourth circuit that controls the temperature of the first temperature-sensitive resistor to be at a fourth temperature that is higher than that of the second temperature-sensitive resistor by a predetermined temperature, and outputs the amount of power corresponding to power consumption for maintaining it at the temperature.

Description

  The present invention relates to a flow rate / temperature / humidity sensor for discriminating whether or not a test gas blown is human breath, and an alcohol concentration measuring apparatus capable of preventing drunk driving using the sensor.

As for driving cars, despite the stricter regulations, accidents caused by drunk driving are unending. For this reason, a drunk driving prevention device that tests the driver's condition and prohibits the operation of the automobile when it is determined to be inappropriate for driving is desired. Already, in some countries and regions, drunk driving prevention devices are required for violators.
As a drunk driving prevention device, it is possible to collect a breath of a driver that is directly blown and measure an alcohol concentration contained in the breath (for example, refer to Patent Document 1) or a human body without using a driver's breath. Various forms of drunk driving prevention devices are known, such as those that detect the alcohol concentration in sweat emanating from the skin (see, for example, Patent Document 2), and some are already in practical use. .
Among these various drunk driving prevention devices, the most representative form is to measure the concentration of alcohol contained in exhaled breath directly blown by the driver. In such a drunk driving prevention device that measures the alcohol concentration in exhaled breath, it is important to detect not only the measurement accuracy of the alcohol concentration in the exhaled breath but also whether or not the measurement is properly performed. As a fraudulent measure that hinders accurate measurement of alcohol concentration in exhaled breath, instead of blowing human breath directly into the drunk driving prevention device during measurement, introducing exhaled breath stored in balloons etc. before drinking, This is because the outside air is blown by the pump or the breath is blown through the adsorption filter.
For this reason, a method of determining whether or not the test gas introduced into the drunk driving prevention device is a breath of human being blown directly and then measuring the alcohol concentration in the test gas is also adopted. Yes. In many cases, the temperature and humidity of the test gas introduced into the drunk driving prevention apparatus by unauthorized means are different from those of normal human breath. Therefore, it is possible to detect an unauthorized test by measuring the temperature, humidity, and the like of the test gas blown into the drunk driving prevention device (see, for example, Patent Document 3). .
In addition, the European standard EN50436-01 (see Non-Patent Document 1) is defined for the direct blow-type drunk driving prevention device, and the amount of the gas to be blown in is detected in the standard. And illegal means to be detected on the drunk driving prevention device side are defined. These detection functions can be realized by providing a flow sensor or a pressure sensor and a humidity sensor.
In addition, the technique which calculates | requires the water vapor | steam density | concentration, ie, humidity, in gas in a heat conduction hydrogen sensor is known (refer nonpatent literature 2).

JP 2005-69742 A JP 2009-00403 A JP 2009-008499 A

EN50436-01 Fuel cell Vol. 7, February 2007, pp. 57-61

As described above, in the alcohol concentration measuring apparatus for measuring the alcohol (ethanol) concentration contained in the exhaled breath directly, not only the alcohol concentration in the exhalation is accurately measured, but also the introduced test gas is directly injected. It is necessary to discriminate whether or not it is a human exhaled breath and to prevent unauthorized means. In order to prevent impersonation of alcohol detection, for example, in an alcohol detector disclosed in Patent Document 3, temperature and humidity are measured by a temperature sensor and a humidity sensor provided in a passage for exhalation and inspiration, and a wind sensor When it is determined that the air flow detected by the above is a human pattern, the detection result by the alcohol sensor is validated.
However, in the prior art such as the alcohol detector, a plurality of sensors such as a temperature sensor / humidity sensor, wind sensor, etc. must be provided in the flow path of the test gas in order to determine whether the breath is human. I had to. For this reason, there are problems that the number of parts for configuring the necessary sensor is increased and the structure for arranging the sensor is complicated. In addition, in order to detect fraudulent means, for example, obtaining exhalation and inhalation is complicated for the subject, and the method for determining whether or not it is human exhalation is also complicated.
In the direct-injection type alcohol concentration measurement device used for preventing drunk driving and the like, as described above, the flow rate and humidity of the injected test gas are important indicators. Therefore, there is a need for a flow rate / temperature / humidity sensor that can be configured with a small number of parts and can be downsized and highly reliable. By using such a flow rate / temperature / humidity sensor, the flow rate and temperature / humidity can be measured without requiring complicated operation of the subject (driver), and whether or not it is human breath can be easily determined. There is a need for an alcohol concentration measuring device that can be discriminated.

  The present invention has been made in view of the above-described situation, and the flow rate and humidity of the test gas are measured by a sensor that can be configured by a single element, and whether the alcohol test in the breath is properly performed from the measured values. It is an object of the present invention to provide an expiration sensor capable of determining whether or not, and an alcohol concentration measurement apparatus capable of preventing drunk driving using the sensor.

The present invention is as follows.
1. An exhalation sensor used in an alcohol concentration measuring apparatus for measuring an alcohol concentration contained in exhaled breath that is directly blown, provided on one semiconductor substrate and installed in a flow path of a test gas And the second temperature sensitive resistor and the amount of electricity corresponding to the power consumption for controlling the first temperature sensitive resistor to a predetermined first temperature and maintaining the first temperature sensitive resistor at the first temperature. A first circuit for outputting the first temperature sensing element, and a consumption for controlling the first temperature sensing resistor to a predetermined second temperature different from the first temperature and maintaining the first temperature sensing resistor at the second temperature. A second circuit for outputting an amount of electricity corresponding to electric power; and a third circuit for outputting an amount of electricity corresponding to a resistance value of the second temperature sensing resistor having substantially the same temperature as the temperature of the test gas in the flow path. The temperature of the circuit and the first temperature sensing resistor is substantially the same as the temperature of the test gas in the flow path. The fourth temperature is controlled to a fourth temperature which is higher than the second temperature sensitive resistor by a predetermined temperature, and outputs an amount of electricity corresponding to the power consumption for maintaining the first temperature sensitive resistor at the fourth temperature. A breath sensor, wherein the first circuit, the second circuit, and the fourth circuit are configured by switching a configuration of one bridge circuit by a switch unit.
2. Flow rate measuring means for measuring the flow rate of the test gas flowing through the flow path by the output of at least one of the first circuit, the second circuit, and the fourth circuit, and the flow of the test gas are stopped. And a humidity measuring means for switching the first circuit and the second circuit and calculating a humidity corresponding value corresponding to the humidity of the gas to be detected remaining in the flow path by respective outputs thereof. 1. The breath sensor described.
3. The first temperature-sensitive resistor and the second temperature-sensitive resistor are each formed on the surface or inside of an insulating thin film member that covers a substrate removal portion from which a part of the semiconductor substrate has been removed and is self-supporting. . Or 2. An exhalation sensor as described in 1.
4). The first temperature sensitive resistor is disposed on the downstream side in the flow path with respect to the second temperature sensitive resistor. To 3. The breath sensor according to any one of the above.
5. 2. To 4. An alcohol concentration measurement apparatus comprising the breath sensor according to any one of the above, wherein the flow rate measuring unit further detects that the gas to be detected having a flow rate in a predetermined range continuously flows for a predetermined time Is determined to be an appropriate flow rate, and the humidity measuring means further determines that the humidity is appropriate when the humidity-corresponding value is within a predetermined range. When the flow rate of the gas is measured and determined to be the appropriate flow rate, the stop of the blowing is urged, and after the blowing is stopped, the humidity measuring value of the test gas is calculated by the humidity measuring means. And an alcohol concentration measuring device comprising sensor control means for enabling measurement of the alcohol concentration of the test gas introduced from the flow path when it is determined that the humidity is appropriate.
6). An exhalation sensor used in an alcohol concentration measurement device that measures an alcohol concentration contained in exhaled breath directly, and is provided on one semiconductor substrate and installed in a flow path of a test gas. A first temperature sensing resistor, one or more second temperature sensing resistors, and any one of the first temperature sensing resistors is controlled to a predetermined first temperature, and the first temperature sensing resistor is A first circuit that outputs an amount of electricity corresponding to power consumption for maintaining the first temperature, and controlling any one of the first temperature sensitive resistors to a predetermined second temperature different from the first temperature; And a second circuit that outputs an amount of electricity corresponding to power consumption for maintaining the first temperature sensing resistor at the second temperature, and a temperature substantially equal to the temperature of the test gas in the flow path. A third circuit for outputting an amount of electricity corresponding to a resistance value of any one of the second temperature sensitive resistors; The temperature of the first temperature sensitive resistor is higher by a predetermined temperature than any one of the second temperature sensitive resistors set to be substantially the same as the temperature of the test gas in the flow path. And a fourth circuit that outputs a quantity of electricity corresponding to power consumption for controlling the temperature and maintaining the first temperature sensitive resistor at the fourth temperature.
7). Flow rate measuring means for measuring the flow rate of the test gas flowing through the flow path by the output of at least one of the first circuit, the second circuit, and the fourth circuit, and the flow of the test gas are stopped. And a humidity measuring means for calculating a humidity-corresponding value corresponding to the humidity of the test gas remaining in the flow path based on the outputs of the first circuit and the second circuit. The breath sensor described.
8). 5. The first temperature sensitive resistor and the second temperature sensitive resistor are formed on the surface or inside of an insulating thin film member that covers and removes the substrate removal portion from which the semiconductor substrate is partially removed. Or 7. An exhalation sensor as described in 1.
9.2 or more of the first temperature sensitive resistors are disposed as a group of resistors in a direction perpendicular to the flow of the test gas in the flow path and spaced apart from each other, The temperature sensitive resistor is disposed on the upstream side of the flow in the flow path with respect to the group of resistors. To 8. The breath sensor according to any one of the above.
10. Said 7. Thru 9. An alcohol concentration measurement apparatus comprising the breath sensor according to any one of the above, wherein the flow rate measuring unit further detects that the gas to be detected having a flow rate in a predetermined range continuously flows for a predetermined time Is determined to be an appropriate flow rate, and the humidity measuring means further determines that the humidity is appropriate when the humidity-corresponding value is within a predetermined range. When the flow rate of the gas is measured and determined to be the appropriate flow rate, the stop of the blowing is urged, and after the blowing is stopped, the humidity measuring value of the test gas is calculated by the humidity measuring means. And an alcohol concentration measuring device comprising sensor control means for enabling measurement of the alcohol concentration of the test gas introduced from the flow path when it is determined that the humidity is appropriate.

According to the breath sensor of the present invention, the first temperature sensing resistor and the second temperature sensing resistor may be provided on one semiconductor substrate and installed in the flow path of the test gas. The number of parts of the sensor can be reduced compared to the conventional case, and the size and the reliability can be improved. The first circuit, the second circuit, the third circuit, and the fourth circuit are provided, and the first circuit, the second circuit, and the fourth circuit are configured by switching the configuration of one bridge circuit by the switch unit. Therefore, it is possible to measure the flow rate and temperature / humidity of the test gas with a very simple measurement circuit with a small number of parts.
If this breath sensor is applied to a drunk driving prevention device for automobiles, it will detect fraudulent means for alcohol testing at the start of driving, and if the alcohol concentration measured by proper testing is below a specified value, it will allow the engine to start, When unauthorized means are used or when a specified value is exceeded, it is possible to perform control so as to prohibit engine start.

  A flow rate measuring means for measuring a flow rate of the test gas by an output of at least one of the first circuit, the second circuit, and the fourth circuit, and the first circuit after the flow of the test gas is stopped, In the case of comprising a humidity measuring means for switching to the second circuit and calculating a humidity corresponding value corresponding to the humidity of the test gas remaining in the flow path by each output thereof, one breath is blown The exhalation flow rate and humidity can be calculated by a series of controls and measurements on.

When the first temperature sensitive resistor and the second temperature sensitive resistor are respectively formed on the surface or inside of an insulating thin film member that covers and removes the substrate removal portion from which the semiconductor substrate is partially removed. Can reduce the heat capacity of the detection part (temperature-sensitive resistor part), reduce the power consumption for heating the temperature-sensitive resistor, and can change the temperature of the temperature-sensitive resistor quickly.
Further, when the first temperature sensing resistor is disposed downstream of the second temperature sensing resistor in the flow path, the temperature of the second temperature sensing resistor is the first temperature sensing. The flow rate and humidity can be accurately measured without being affected by the heat generated by the resistor.

  An alcohol concentration measurement device comprising any one of the above breath sensors, wherein after the breath is urged to be blown, the flow rate of the test gas is measured by the flow rate measuring means and the flow rate is determined to be appropriate. After the stop is urged and the blowing is stopped, the humidity measurement value is calculated by the humidity measuring means, and if the humidity is determined to be appropriate, the alcohol concentration of the test gas introduced from the flow path is determined. According to the alcohol concentration measuring apparatus provided with the sensor control means that enables the measurement of the flow rate, the humidity and flow rate and humidity can be obtained only by using a temperature-sensitive resistor formed as a single element, and only by breathing in once. Thus, it is possible to determine whether or not the breath is human. This makes it possible to detect fraudulent means and accurately measure alcohol concentration relative to human breath.

  One or two or more first temperature sensitive resistors and one or two or more second temperature sensitive resistors provided in one semiconductor substrate and installed in a flow path of a test gas, and first to fourth According to the breath sensor comprising a circuit, a plurality of temperature sensitive resistors may be provided on a single semiconductor substrate and installed in the flow path of the test gas, so that the detection unit is configured by a single element. Therefore, the number of parts of the sensor can be reduced compared to the conventional one, and the size and the reliability can be improved. If a temperature sensitive resistor connected to each of the first to fourth circuits is provided separately, the measurement of the test gas can be performed with a very simple configuration and control without switching the first to fourth circuits. It can be carried out.

  In the case where the flow rate measuring means and the humidity measuring means are provided, the flow rate and humidity of the exhaled breath can be calculated by a series of control and measurement for one breath.

When the first temperature-sensitive resistor and the second temperature-sensitive resistor are formed on the surface or inside of an insulating thin film member that covers and removes the substrate removal portion from which a part of the semiconductor substrate has been removed. It is possible to reduce the heat capacity of the detection part (temperature-sensitive resistor part), reduce the power consumption for heating the temperature-sensitive resistor, and change the temperature of the temperature-sensitive resistor quickly.
The two or more first temperature sensitive resistors are arranged as a group of resistors in a direction perpendicular to the flow of the test gas in the flow path and spaced apart from each other. When the temperature resistor is disposed on the upstream side of the flow in the flow path with respect to the group of resistors, the temperature resistor suppresses the influence of heat generated by the first temperature resistor and 2. The temperature of the temperature sensitive resistor can be prevented from being affected by the heat generated by the first group of resistors, and the flow rate and humidity can be accurately measured.

  According to the alcohol concentration measuring apparatus including any one of the above breath sensors, a temperature sensing resistor formed as a single element is used, and only one breath is blown, and the flow rate and humidity of the human make a human breath. Whether or not exhalation can be determined. This makes it possible to detect fraudulent means and accurately measure alcohol concentration relative to human breath.

The present invention is further illustrated by the following detailed description with reference to a number of referenced drawings, given non-limiting examples of exemplary embodiments according to the present invention, wherein like reference numerals denote Similar parts are shown throughout the figure.
It is a typical block diagram for demonstrating the structure of an alcohol concentration measuring apparatus provided with the breath sensor which concerns on this embodiment. It is a block diagram showing the structure of the breath sensor which concerns on this embodiment, and an alcohol concentration measuring apparatus provided with the same. It is the typical top view for explaining the detection part provided in the semiconductor substrate, and its AA 'sectional view. It is the typical top view for explaining the modification of the detection part provided in the semiconductor substrate, and its BB 'sectional view. It is a circuit diagram showing the circuit structure of the breath sensor which concerns on this embodiment. 6 is a table for explaining switching of circuit configuration by switch means in a flow rate measurement step and a humidity measurement step performed using the circuit shown in the previous figure. It is a circuit diagram showing the structure of the measurement circuit (4th circuit) in the flow volume measurement step of an expiration sensor. It is a circuit diagram which shows the structure of the measurement circuit (a 1st circuit and a 3rd circuit) during the humidity measurement step of an expiration sensor while controlling a 1st temperature sensitive resistor to 1st temperature. It is a circuit diagram which shows the structure of the measurement circuit (a 2nd circuit and a 3rd circuit) while controlling the 1st temperature sensitive resistor to 2nd temperature in the humidity measurement step of a breath sensor. It is a flowchart showing the control method in the case of using the alcohol concentration measuring apparatus using the breath sensor which concerns on this embodiment as a drunk driving prevention apparatus of a motor vehicle. It is a flowchart showing the control method in the flow measurement step of an expiration sensor. It is a flowchart showing the control method in the humidity measurement step of the breath sensor. It is a typical top view for explaining another modification of a detection part of an expiration sensor. It is a circuit diagram showing the circuit structure of the breath sensor which uses the detection part shown in the previous figure. 6 is a table for explaining switching of circuit configuration by switch means in a flow rate measurement step and a humidity measurement step performed using the circuit shown in the previous figure. 6 is a schematic top view for explaining a detection unit of the breath sensor according to Embodiment 2. FIG. 6 is a circuit diagram illustrating a circuit configuration of an expiration sensor according to Embodiment 2. FIG. 6 is a schematic top view for explaining a detection unit of an expiration sensor according to Embodiment 3. FIG. 6 is a circuit diagram illustrating a circuit configuration of an expiration sensor according to Embodiment 3. FIG. It is typical sectional drawing for demonstrating an alcohol concentration measurement part.

Hereinafter, the breath sensor and the alcohol concentration measurement device of the present invention will be described in detail with reference to FIGS.
The breath sensor of the present invention is used in an alcohol concentration measuring apparatus that directly breathes into a person and measures the concentration of alcohol contained in the breath. This alcohol concentration measuring device can be used as, for example, a drunk driving prevention device installed in an automobile.
FIG. 1 schematically shows a schematic configuration of an alcohol concentration measuring apparatus including the breath sensor. The alcohol concentration measurement apparatus 100 includes a main flow tube 110 that forms a flow path 111 of exhaled air 112 blown from the left side in the figure, and an alcohol concentration measurement unit 120. In this example, the inlet side of the alcohol concentration measurement unit 120 is connected to the main flow pipe 110 via the introduction pipe 121, and the outlet side is connected to the pump 123 via the exhaust pipe 122. A part of the exhaled air (referred to as “test gas”) flowing through the flow path 111 is introduced into the alcohol concentration measurement unit 120 by the pump 123.

  Inside the pipe wall of the main flow pipe 110, an exhalation sensor detection unit 114 (2) for measuring the flow rate and temperature / humidity of the test gas is installed so as to be exposed. Usually, since there is a difference in how people breathe, the measurement of the test gas using the inspection unit 114 is affected by how the breath is blown. In order to reduce this influence, the narrowed portion 116 is provided on the inner wall of the main flow pipe 110 in this example. However, the present invention is not limited to this, and the flow of the test gas is corrected by providing a wire mesh, a resin filter, or the like. It may be. Further, in this example, by providing a heater 115 on the pipe wall of the main flow pipe 110, condensation and freezing before using the breath sensor are removed, condensation by the breath is prevented, and the temperature of the test gas is kept constant. I try to keep it.

(Configuration of breath sensor and alcohol concentration measuring device)
This breath sensor is configured by installing at least a detection unit provided with one or two or more temperature sensitive resistors in a flow path 111 of a test gas. FIG. 2 shows a configuration of an alcohol concentration measuring apparatus centering on an expiration sensor 1 using two temperature sensitive resistors. The breath sensor 1 includes at least a flow rate and a humidity of a test gas connected to the detection unit 2 provided with the first temperature sensing resistor 31 and the second temperature sensing resistor 32 on one semiconductor substrate, and each temperature sensing resistor. And a measurement circuit 4 for measuring. The measurement circuit 4 can be connected to the control unit 5.

The first temperature-sensitive resistor 31 and the second temperature-sensitive resistor 32 are temperature-sensitive resistors whose resistance values change with their own temperature changes. The first temperature sensing resistor 31 and the second temperature sensing resistor 32 can be one or more, respectively, and may be provided with an appropriate number depending on the configuration of the measurement circuit.
The material of each temperature-sensitive resistor is not particularly limited, but platinum (Pt) having a constant resistance temperature coefficient (TCR) and a resistance value that is easy to handle is preferable. Each temperature sensitive resistor can be formed as a thin film resistor on one semiconductor substrate. Moreover, it is preferable that each temperature sensitive resistor is provided by being embedded in the surface of a self-supporting insulating thin film member that covers the defect formed in the semiconductor substrate, or in the insulating thin film member.
The first temperature sensitive resistor 31 that is used by generating heat is relatively low resistance (for example, about 100Ω to 200Ω), and the second temperature sensitive resistor 32 that is used so as not to generate heat is relatively high resistance (for example, 3 kΩ to 10 kΩ). Degree).

  Further, in the normal (forward direction) flow 112 of the test gas in the flow path 111, the first temperature sensing resistor 31 is disposed downstream of the second temperature sensing resistor 32. When two or more temperature sensing resistors are provided as the first temperature sensing resistor, the atmosphere that has passed over each temperature sensing resistor is installed so that it does not pass over any other temperature sensing resistor. Is done. That is, in this case, two or more first temperature sensitive resistors are arranged as a group of resistors in a direction perpendicular to the flow 112 of the test gas in the flow path and spaced apart from each other. The temperature sensitive resistor is disposed upstream of the flow 112 in the flow path with respect to the group of resistors.

The measurement circuit 4 includes four electronic circuits, a first circuit 41, a second circuit 42, a third circuit 43, and a fourth circuit 44.
The first circuit 41 controls the first temperature sensitive resistor 31 to a predetermined first temperature (T1) and consumes power (P1) for keeping the first temperature sensitive resistor 31 at the first temperature T1. It is configured as a bridge circuit that outputs an electric quantity E1 corresponding to. The first temperature T1 can be determined by the design of the bridge circuit (for example, 200 ° C.).
The second circuit 42 controls the first temperature sensitive resistor 31 to a predetermined second temperature (T2) different from the first temperature T1, and the first temperature sensitive resistor 31 is set to the second temperature T2. It is configured as a bridge circuit that outputs an electric quantity E2 corresponding to the power consumption (P2) for maintaining. The second temperature T2 can be determined by the design of the bridge circuit (for example, 300 ° C.).
The third circuit 43 is configured to output an electric quantity E3 corresponding to the resistance value of the second temperature sensitive resistor 32 having substantially the same temperature as the temperature (T3) of the test gas in the flow path 111. That is, the third circuit 43 is a circuit for measuring the temperature of the test gas, and a known circuit can be used.
The fourth circuit 44 raises the temperature of the first temperature sensing resistor 31 by a predetermined temperature (ΔT4) relative to the second temperature sensing resistor 32 having substantially the same temperature as the temperature T3 of the test gas in the flow path 111. It is configured as a bridge circuit that controls the fourth temperature (T4) and outputs an electric quantity E4 corresponding to the power consumption (P4) for keeping the first temperature sensitive resistor 31 at the fourth temperature T4. The predetermined temperature ΔT4 can be determined by the design of the bridge circuit (for example, 200 to 300 ° C.).

  The outputs E1 to E4 of each circuit are connected to the control unit 5. The outputs E1 to E4 may be any electric quantity corresponding to each of the power consumption or the resistance value, and may be any output format of voltage, current, and power. In the following description and circuit diagram, voltage values are used as the outputs E1 to E4.

  The first circuit 41, the second circuit 42, and the fourth circuit 44 can be configured by switching the configuration of one bridge circuit by a switch circuit 45. For this reason, the measurement circuit 4 includes a switch circuit 45 using an arbitrary switch element. For example, the switch means can be configured by the switch circuit 45 and a program provided in the control unit 5. The number of switch elements and the configuration of the switch circuit 45 can be appropriately determined according to the configurations of the first to fourth circuits.

The outputs E1 to E4 of the respective circuits can be configured to be read by the control unit 5. The control unit 5 can be preferably configured to include a microprocessor and peripheral circuits, a memory (ROM, RAM), an input / output interface circuit, and the like.
The expiration sensor 1 can include a flow rate measuring means 51 and a humidity measuring means 52. The flow rate measuring means 51 and the humidity measuring means 52 can be mainly configured by a program stored in the control unit 5.
The flow rate measuring means 51 is configured to flow through the flow path 111 by at least one of the outputs E1, E2, and E4 in a state where the flow of the test gas is in the flow path 111, that is, in a state where exhalation is blown. It is configured to measure the flow rate of the sample gas. The flow rate measuring means 51 can be further configured to determine an appropriate flow rate when it is detected that a test gas having a flow rate in a predetermined range continuously flows for a predetermined time.
The humidity measuring means 52 switches the first circuit 41 and the second circuit 42 by the switch means after the flow of the test gas in the flow path 111 is stopped, and the flow path 111 by the outputs E1 and E2 thereof. A value (humidity corresponding value) corresponding to the humidity of the gas to be detected remaining therein is calculated. The humidity measuring means 52 can be further configured to determine the appropriate humidity when the humidity corresponding value is within a predetermined range.

The alcohol concentration measuring device 100 can be configured by including the breath sensor 1 configured as described above, the alcohol concentration measuring unit 120, and the sensor control means 53.
The alcohol concentration measuring apparatus 100 is provided with an interface circuit with peripheral components such as the heater 115, the pump 123, a valve for controlling the flow of the test gas, and the control means thereof as required. be able to. In addition, it is possible to provide notifying means for urging the subject to start and end of exhalation. The configuration of the notification means is not limited, and any means such as display by a light emitter or a display, voice, sound, or the like can be provided.
When the alcohol concentration measurement device 100 is a drunk driving prevention device installed in an automobile, it may be further provided with an interface or the like that is activated by an engine key and permits the start of the engine.

The sensor control means 53 provided in the alcohol concentration measurement apparatus 100 can be configured by hardware of the control unit 5 and a program stored in the control unit 5.
The sensor control means 53 urges the subject to blow in exhaled air, measures the flow rate of the test gas by the flow rate measuring means 51, and stops the blowing if it is determined to be an appropriate flow rate. Can be configured to prompt. Then, after it is determined that the flow rate is appropriate and the blowing is stopped, measurement is performed by the humidity measuring means 52 to calculate the humidity-corresponding value. It is possible to configure the measurement gas introduced into the concentration measuring unit 120 so that the alcohol concentration can be measured. Here, “allows measurement of alcohol concentration” means that the alcohol concentration measurement device 100 may be configured so that the alcohol concentration is measured after that, or the exhaled breath whose flow rate and humidity have been measured has already been measured. It may be configured to validate the measured alcohol concentration value.

The method and configuration of the alcohol concentration measurement unit 120 are not particularly limited as long as alcohol contained in the test gas can be detected. Well-known alcohol detectors such as electrochemical, infrared absorption, and semiconductor methods can be used.
As an example, FIG. 20 is a diagram schematically showing a non-dispersive infrared absorption (NDIR) type alcohol detector. The test gas is introduced from the introduction pipe 121 into the lens barrel 201 (121a) and discharged to the exhaust pipe 122 (121b). A light emitter 211 is provided on one end side in the lens barrel 201 that serves as a flow path for the test gas, and a reflective surface 202 is formed on the back side of the light emitter 211. Infrared detection elements 223 and 224 are provided on the other end side in the lens barrel 201, and each infrared detection element receives light emitted from the light emitter 211 via the wavelength selection filters 221 and 222, respectively. The light emitter 211 outputs light in a wide wavelength range (for example, visible to far infrared), and the wavelength selection filter allows only infrared light in a certain wavelength range to pass. Here, the wavelength selection filter 221 passes only infrared light in the first wavelength region centered on the absorption wavelength of ethanol (for example, 3.4 μm), and the wavelength selection filter 222 is a kind of ethanol and coexisting gas. Then, it is possible to design so that only infrared light in the second wavelength region centered on a wavelength that is not absorbed (for example, 3.9 μm) is allowed to pass.

  Then, as the alcohol concentration in the test gas increases, the absorption of infrared light in the first wavelength range by ethanol increases, so the amount of light received by the infrared detection element 223 through the wavelength selection filter 221 decreases. On the other hand, since the amount of absorption of infrared light in the second wavelength region does not change depending on the ethanol concentration, the amount of light received by the infrared detection element 224 through the wavelength selection filter 222 does not depend on the ethanol concentration. Therefore, the influence of disturbance such as a change in emission intensity of the light emitter 211 can be compensated by the amount of light received by the infrared detection element 224, and the ethanol concentration can be accurately measured by the amount of light received by the infrared detection element 223.

FIG. 3 is a schematic top view for explaining the configuration of the detection unit 2 provided on the semiconductor substrate, and a cross-sectional view thereof taken along the line AA ′. In this example, the first temperature sensing resistor 31 and the second temperature sensing resistor 32 are each composed of one temperature sensing resistor, but one or both of them are composed of two or more temperature sensing resistors. It is also possible (see FIG. 13).
As shown in the cross-sectional view, the first temperature sensing resistor 31 and the second temperature sensing resistor 32 are formed in a thin film shape in each partitioned region on one semiconductor substrate 21 that is the base of the detection unit 2. Can be provided. The first temperature sensing resistor 31 is disposed downstream of the normal flow of the test gas 112 in the flow path 111 with respect to the second temperature sensing resistor 32. In addition, 31a, 31b in a figure shows the electrical connection terminal of the 1st temperature sensing resistor 31 (it describes similarly about another temperature sensing resistor and its drawing).

The first temperature sensitive resistor 31 and the second temperature sensitive resistor 32 can be formed on the surface of the insulating thin film member 22 formed on the semiconductor substrate 21 using an insulating material. Further, the temperature sensitive resistors 31 and 32 are formed on the insulating thin film 22, and the thin film 23 is formed using an insulating material, thereby embedding the temperature sensitive resistors in the entire insulating thin film member (22 and 23). can do.
The first temperature sensitive resistor 31 and the second temperature sensitive resistor 32 are preferably provided on the substrate removal portions (211 and 212) from which a part of the semiconductor substrate 21 is removed. For example, when a silicon substrate is used as the semiconductor substrate, the substrate removal portion 211 and the like can be formed by silicon anisotropic etching or the like. The insulating thin film member (22, or 22 and 23) can be formed so as to cover the substrate removing portion 211 and the like and to be self-supporting. That is, the first temperature sensitive resistor 31 and the second temperature sensitive resistor 32 are formed on the surface or inside of the insulating thin film member.

  FIG. 4 is a top view and a BB ′ sectional view for explaining a modification of the detection unit 2. In this example, a partition wall 117 is provided in the main flow tube 110, and only the portion where the temperature sensitive resistor (31, 32) is provided is exposed in the test gas. And the outside of the flow path 118 are partitioned by a partition wall 117. The connection terminals 31a and the like of each temperature sensitive resistor can be placed outside the flow path 118. Other structures can be the same as the example shown in FIG.

(Operation of breath sensor and alcohol concentration measuring device)
(1) Measurement of flow rate At least the first temperature sensing resistor 31 and the second temperature sensing resistor 32 of the detection unit 2 of the breath sensor 1 are installed in the flow path 111 of the test gas. Then, the flow rate of the test gas can be measured by the flow rate measuring means 51.
The flow rate measuring means 51 controls the first temperature sensing resistor 31 to a temperature T4 that is higher than the temperature T3 of the test gas by a predetermined temperature ΔT4, or to a predetermined temperature T1 or T2. Measure the gas flow rate. When the flow rate within a predetermined time is within the specified range, it can be determined that an appropriate amount of the test gas has been introduced (appropriate flow rate). For example, the prescribed range can be determined in advance based on statistical data on the breathing operation of a person and stored in a memory in the control unit 5.

The flow rate measuring means 51 connects the first temperature sensitive resistor 31 to a bridge circuit (the first, second or fourth circuit) that keeps its resistance value constant. Thus, the first temperature sensing resistor 31 is driven to maintain a constant temperature (T1, T2, or a temperature T4 that is higher than the temperature T3 of the test gas by a constant temperature ΔT4).
In this state, the larger the flow rate of the test gas, the more electric power (voltage or current) is required to keep the temperature sensitive resistor at a constant resistance value. Further, the higher the thermal conductivity of the test gas, the more easily the heat of the temperature sensitive resistor is taken away by the test gas. Therefore, in this state, the electric power for driving the temperature sensitive resistor includes information on the flow rate and the thermal conductivity of the test gas that varies depending on the temperature and humidity.

  The electric power for driving the first temperature sensitive resistor 31 can be known by measuring the balanced voltage and the balanced current of the bridge circuit to which the first temperature sensitive resistor 31 is connected. The output E1 of the first circuit 41, the output E2 of the second circuit 42, and the output E4 of the fourth circuit 44 can be the balanced voltage of each bridge circuit. Then, the electric powers P1 and P2 for maintaining the first temperature sensing resistor 31 at the temperatures T1 and T2 can be calculated from the values of the outputs E1 and E2. Further, the electric power P4 for maintaining the first temperature sensitive resistor 31 at the temperature T4 can be calculated from the value of the output E4.

The second temperature sensitive resistor 32 is connected to the third or fourth circuit and is driven by a small amount of electric power that does not generate heat substantially. As a result, the resistance value of the second temperature sensitive resistor 32 becomes a value corresponding to the temperature T3 of the surrounding test gas. That is, since the temperature of the second temperature sensing resistor 32 is kept substantially the same as the temperature T3 of the test gas, the temperature T3 of the test gas can be known by measuring the resistance value. From the third circuit 43, an output E3 corresponding to the resistance value of the second temperature sensing resistor 32 is obtained, whereby the temperature T3 of the test gas can be calculated.
When the second temperature sensing resistor 32 is connected to the fourth circuit 44, the temperature of the second temperature sensing resistor 32, which is substantially the same as the temperature T3 of the test gas, is used as a reference, and only a constant temperature ΔT4 is set. The first temperature sensing resistor 31 is driven so that the temperature T4 becomes high (T4 = T3 + ΔT4).

  As described above, the temperature T3 of the test gas, the power P1 for keeping the first temperature sensing resistor 31 at the temperature T1, the power P2 for keeping the first temperature sensing resistor 31 at the temperature T2, and the first temperature sensing. The electric power P4 for keeping the resistor 31 at a temperature T4 higher by ΔT4 than the temperature T3 of the test gas can be calculated. Further, the temperatures T1, T2, and ΔT4 can be constant values determined by the design of the bridge circuit.

Here, when the mass flow rate of the test gas in the flow path 111 is Fm, the following equation (Equation 1) is established from a general theory.
P1 = (A11 + A12 · Fm ^1/2 ) · (T1-T3)
P2 = (A21 + A22 · Fm ^1/2 ) · (T2-T3)
P4 = (A41 + A42 · Fm ^1/2 ) · ΔT4
In the above equation, A11, A12, A21, A22, A41, and A42 are constants determined by the temperatures T1, T2, T3, ΔT4, and the component of the test gas flowing through the flow path 111.
In many cases, it can be assumed that the following equation (Equation 2) holds.
A11 = A21 = A41, A12 = A22 = A42
In many cases, the values of A11 / A21, A12 / A22, A11 / A41, and A12 / A42 may be substantially constant even when the component of the test gas flowing through the flow path 111 changes. it can.

Therefore, the mass flow rate Fm of the test gas flowing through the flow path 111 is calculated from the electric power (P1, P2 or P4) necessary for maintaining the first temperature sensitive resistor 31 at the predetermined temperature (T1, T2 or T4). be able to.
Since changes in A11, A12, A21, A22, A41, and A42 due to humidity are not so large, the flow rate can be measured while ignoring those changes in a situation where there is a flow of the test gas.

(2) Measurement of humidity Next, after the blowing of exhalation is stopped, the test gas is measured by the humidity measuring means 52 in a state where the test gas stays in the flow path 111. Calculate the humidity value. Then, when the calculated humidity corresponding value is within the specified range, the humidity measuring unit 52 can determine that the test gas has an appropriate humidity (appropriate humidity). As the specified range, for example, a specified value can be determined in advance based on statistical data on human expiration, and can be stored in a memory in the control unit 5.
The humidity measuring means 52 obtains electric power P1 and P2 required to maintain the first temperature sensitive resistor 31 at different temperatures T1 and T2, respectively, and a humidity corresponding value (for example, P1 and P1) corresponding to the humidity of the test gas. P2 ratio) is calculated. The electric powers P1 and P2 can be obtained in the same manner as described above based on the outputs E1 and E2 of the first circuit 41 and the second circuit 42.

In Formula 1, when water vapor is included in the test gas, the polarity of water molecules is large. Therefore, the higher the water vapor concentration, that is, the humidity, the more the Formula 2 does not hold. That is,
A11 = A21, A12 = A22
The deviation from is increased. The deviation depends on the water vapor concentration, that is, the humidity (see Non-Patent Document 2). Therefore, by obtaining A11, A21, etc., a humidity corresponding value corresponding to the humidity of the test gas can be calculated, and the humidity can be determined.

When there is no flow of the test gas, assuming that the power consumption of the first temperature sensing resistor when connected to the first circuit and the second circuit is P1s and P2s, respectively, Can be represented.
P1s = A11 · (T1-T3)
P2s = A21 ・ (T2-T3)
For this reason, by measuring P1s and P2s, it becomes relatively easy to detect changes in the values of A11 and A21. The values of A11 and A21 may be obtained and compared individually, but in many cases, the ratio of A11 and A21 (A11 / A21) is calculated from the ratio of P1s and P2s (P1s / P2s) and the value is calculated. It can be used to determine the humidity of the test gas.
In this exhalation sensor, since the exhalation of human being is assumed as the test gas, if the value of P1s / P2s in the gas with the humidity of the exhalation of human is examined and stored in the memory in the control unit 5, By calculating the value of P1s / P2s from the actual measurement value of the test gas, it is possible to determine whether or not the test gas has a humidity equivalent to human breath.

(Embodiment 1)
5 to 9 show a specific example (Embodiment 1) of the breath sensor 1. The breath sensor 1 can be configured by a measurement circuit 4 illustrated in FIG. The measurement circuit 4 includes two circuits 4a and 4b, and includes switch circuits (switches S1, S2, and S3) for switching between the circuit configurations. The switches S1 and S2 switch whether the second temperature sensitive resistor 32 is connected to the circuit 4a or the circuit 4b, and the switch S3 is turned on (connected) and turned off to change the resistance value in the circuit 4a. (Disconnect) is switched.

  In the circuit 4a, two series circuits are connected in parallel between a constant DC power supply (+ V) connected via a transistor Q1 controlled by the output of the differential amplifier A1 and a reference potential GND. Yes. In one of the series circuits, the resistor element R1 and the first temperature-sensitive resistor 31 are connected in series in this order from the DC power supply side. In the other series circuit, when the switch S3 is off and the switch S1 is on the b side, the resistance elements R2, R3, and R5 are connected in series, the switch S3 is off, and the switch S1 is on the a side. In the case, the resistance elements R2, R3 and the second temperature sensitive resistor 32 are connected in series. When the switch S3 is on, R4 is connected in parallel to the resistor element R3. And between the resistance element R1 of the one series circuit and the first temperature sensitive resistor 31, and between the resistance elements R2 and R3 of the other series circuit are respectively connected to the input of the differential amplifier A1. Constitutes a bridge circuit. The output Ea (hereinafter also referred to as “balanced output”) of the differential amplifier A1 can be read by the control unit 5.

  In the circuit 4b, resistance elements R8 and R9 are connected in series between the output of the differential amplifier A2 and the reference potential GND, and the resistance elements R8 and R9 are connected to one input of the differential amplifier A2. Yes. The other input of the differential amplifier A2 is connected to a DC power supply (+ V) via a resistance element R6. The other input of the differential amplifier A2 is connected to the reference potential GND via the second temperature sensing resistor 32 when the switch S2 is on the a side, and is a resistive element when the switch S2 is on the b side. It is connected to the reference potential GND through R7. The output Eb of the differential amplifier A2 can be read by the control unit 5.

FIG. 6 shows a connection state of the switch circuits S1 to S3 when the flow rate measurement and the humidity measurement are performed by the circuit shown in FIG. First, in the flow rate measurement step of measuring the flow rate of the test gas, the switch S1 is connected to the a side and the S2 is connected to the b side. The switch S3 can be turned on or off depending on the design values of the resistance elements R3 and R4. In this state, the measurement circuit 4 is configured as a fourth circuit 44 as shown in FIG.
By using the fourth circuit 44, the first temperature sensing resistor is set to a temperature higher by ΔT4 than the temperature T3 as the balanced output E4 by the resistance value of the second temperature sensing resistor 32 having substantially the same temperature as the temperature T3 of the test gas. A voltage value corresponding to the power required to maintain 31 can be obtained.

Next, in the humidity measurement process for measuring the humidity of the test gas, the switch S1 is connected to the b side and the S2 is connected to the a side. When the switch S3 is turned on, the measurement circuit 4 is configured as a first circuit 41 and a third circuit 43 as shown in FIG. When the switch S3 is turned off, the measurement circuit 4 is configured as a second circuit 42 and a third circuit 43 as shown in FIG.
By the first circuit 41 shown in FIG. 8, the first temperature sensing resistor 31 is driven to generate heat at the first temperature T1 determined by design, and the electric power P1 for maintaining the first temperature T1 is supplied. . The output E1 of the first circuit has a voltage value corresponding to this balanced power P1s.
Also, the second circuit 42 shown in FIG. 9 drives the first temperature sensing resistor 31 to generate heat at the second temperature T2 determined by the design, and supplies electric power P2 for maintaining the second temperature T2. Is done. The output E2 of the second circuit has a voltage value corresponding to this balanced power P2s.
Further, the temperature of the second temperature sensitive resistor 32 connected to the third circuit 43 shown in FIGS. 8 and 9 is equal to the temperature T3 of the test gas. Then, since the output E3 of the third circuit 43 becomes a voltage value corresponding to the resistance value of the second temperature sensitive resistor 32, the temperature T3 of the test gas can be measured from the value of the output E3.

  As described above, the P1s and P2s can be obtained under the conditions of the known temperatures T1 and T2 and the measured temperature T3 in the state where the test gas stays in the flow path 111. The ratio (P1s / P2s) is calculated as a humidity-corresponding value, and the humidity of the test gas can be determined.

(Control method of breath sensor and alcohol concentration measuring device)
FIG. 10 shows a control method for an example in which the alcohol concentration measurement apparatus 100 including the breath sensor 1 is used as an automobile drunk driving prevention apparatus. This control can be executed mainly by a program (sensor control means 53) stored in the control unit 5 using the hardware of the control unit 5.
First, the alcohol concentration measuring apparatus 100 is powered on by a startup operation such as turning on the engine key (S101). In this initial state, the engine is locked so as not to start.
Next, the inside of the control unit 5 is initialized and an internal timer is started to start timing (S102). Then, if necessary, it waits for completion of its own measurement preparation such as energizing the heater inside the apparatus to reach a predetermined temperature (S103).

When the measurement preparation is completed, the driver (subject) is prompted to breathe in by any notification means such as display, light emission, sound, and voice (S104).
Then, the flow rate measuring means 51 measures the flow rate of the exhaled breath to determine whether or not the exhaled breath is an appropriate flow rate (S105).
If it is not determined that the exhaled breath is an appropriate flow rate (“No” in S106), the flow rate of the exhalation can be measured again. At this time, it is possible to urge the subject to perform the exhalation operation again by any notifying means.
On the other hand, when it is determined that the exhaled breath is at an appropriate flow rate (“Yes” in S106), the inhalation of the exhalation is urged by an arbitrary notification means (S107). Even if urged to stop blowing, the subject does not always stop blowing, so a valve is provided on the inlet side of the main flow pipe 110 and the flow of the test gas is forcibly stopped by closing the valve. Also good.
In addition, although not shown, a part of the test gas in the main flow tube 110 is alcoholized at an appropriate timing from immediately before prompting the stop of exhalation to immediately after being determined to be appropriate humidity in the next humidity measurement. It is introduced into the concentration measuring unit 120.

After it is determined that the exhalation is at an appropriate flow rate and the exhalation is stopped, the humidity of the test gas staying in the main flow pipe 110 is measured by the humidity measuring means 52, and whether the humidity is at an appropriate humidity. It is determined whether or not (S108).
When it is not determined that the test gas has an appropriate humidity (“No” in S109), the measurement can be performed again from the flow rate measurement of the expiration. At this time, it is possible to urge the subject to perform the exhalation operation again by any notifying means.
On the other hand, when it is determined that the test gas has an appropriate humidity (“Yes” in S109), the process proceeds to the next alcohol concentration measurement.

For the test gas introduced into the alcohol concentration measuring unit 120, the alcohol concentration is measured (S110).
When the measured alcohol concentration exceeds the predetermined value (“No” in S111), the measurement can be performed again from the measurement of the exhalation flow rate. At this time, it is possible to urge the subject to perform the exhalation operation again by any notifying means.
On the other hand, if the measured alcohol concentration is equal to or lower than the predetermined value (“Yes” in S111), the engine can be started (S112). Furthermore, the start of the engine is monitored (S113), and when the engine is started within a predetermined time, the process of the drunk driving prevention device is ended. On the other hand, when the engine is not started within a predetermined time, the engine start can be prohibited, and the process from the breath injection to the alcohol concentration measurement can be performed again.

FIG. 11 shows a control example of the flow rate measuring step (S105). This control can be performed by controlling the switch circuit by the flow rate measuring means 51 as shown in the flow rate measuring step (see FIG. 6).
First, the switch circuit 45 selects the fourth circuit 44 (S21), and waits for a time required for the first temperature-sensitive resistor 31 to rise to the predetermined temperature T4 (= T3 + ΔT4) (S22). Thereafter, the value of the output E4 of the fourth circuit is read (S23). Then, based on the value of the output E4, the flow rate Fm (or flow velocity) of the test gas is calculated using the relationship of the formula 1 (S24).
Next, it is determined whether or not the obtained flow rate Fm is within a specified range (S25). The specified range is a range that can be determined as human exhalation if exhalation is blown at the flow rate, and can be determined by comparison with a predetermined value stored in a memory in the control unit 5.

If the flow rate Fm is within the specified range, it is determined whether the flow rate Fm is within the specified range for a predetermined time (for example, 3 seconds) (S26). If it is less than the predetermined time, the flow rate measurement and determination of whether it is within the specified range (S23 to S25) are repeated at predetermined intervals (for example, 0.1 seconds), and the result is recorded. If the flow rate Fm is within the specified range for a predetermined time, it is determined that the exhalation is an appropriate flow rate (S27), and the measurement ends.
On the other hand, if it is determined in step S25 that the flow rate Fm is not in the proper range, it is determined that the exhalation is not in the proper flow rate, and the measurement is terminated.

Although the fourth circuit 44 is used in this example, the flow rate can be measured using the first circuit 41 or the second circuit 42 as described above. Even in such a case, the flow rate Fm can be calculated by the same control method as in this example, and it can be determined whether the flow rate is within an appropriate range.
Further, the method for determining human exhalation from the measured flow rate is not limited to the method shown in this example, and various modifications and other methods can be applied.

FIG. 12 shows a control example of the humidity measuring step (S108). This control can be performed by controlling the switch circuit by the humidity measuring means 52 as shown in the humidity measuring step (see FIG. 6). Humidity measurement is performed after the flow of the test gas around the temperature-sensitive resistor ceases.
The third circuit 43 is selected by the switch circuit 45 (S31), and the value of the output E3 is read and stored (S32). Since the second temperature sensing resistor 32 incorporated in the third circuit 43 is placed in the test gas without actually generating heat, the value of the output E3 is the resistance of the second temperature sensing resistor 32. Corresponds to the value, and thus corresponds to the temperature T3 of the test gas. Note that the measurement of the temperature T3 of the test gas can be performed at an appropriate timing.

Further, the first circuit 41 is selected by the switch circuit 45 (S33), and the first temperature sensitive resistor 31 waits for a time required to reach the first temperature T1 determined by the design (S34). Thus, the first temperature sensitive resistor 31 is controlled to the first temperature T1. Thereafter, the value of the output E1 of the first circuit is read and stored (S35). The value of the output E1 corresponds to the power consumption P1s for keeping the first temperature sensitive resistor 31 at the first temperature T1.
Further, the second circuit 42 is selected (S36), and the first temperature sensitive resistor 31 waits for a time required to reach the second temperature T2 determined by the design (S37). Thus, the first temperature sensitive resistor 31 is controlled to the second temperature T2. Thereafter, the value of the output E2 of the second circuit is read and stored (S38). The value of the output E2 corresponds to the power consumption P2s for keeping the first temperature sensitive resistor 31 at the second temperature T2.
The measurement of the output E1 at the first temperature T1 and the measurement of the output E2 at the second temperature T2 are not limited. Further, by alternately switching the first circuit 41 and the second circuit 42, the outputs E1 and E2 can be measured at regular intervals (for example, 0.1 seconds).

Based on the values of the outputs E3, E1, and E2 stored in the respective steps, the humidity corresponding value of the test gas is calculated (S39). For example, the humidity corresponding value h (for example, E1 / E2, P1s / P2s, or humidity obtained from them) is calculated based on the values of the outputs E1, E2, and E3 measured within a certain time.
Then, the calculated humidity corresponding value h is compared with the prescribed values (h1, h2) stored in the memory in the control unit 5 in advance, and whether the value is within the prescribed value range, that is, a value corresponding to human expiration. It is determined whether or not (S40). If the humidity corresponding value h is within the specified range, it is determined that the humidity is appropriate (S41), and the humidity measurement is terminated. On the other hand, if it is determined that the calculated humidity is not within the specified range, it is determined that the exhaled breath is not the appropriate humidity, and the measurement is terminated.

(Modification of Embodiment 1)
The exhalation sensor 1 described above can be configured with various modifications. For example, in FIG. 13, the breath sensor 11 includes two temperature sensitive resistors 311 and 312 as the first temperature sensitive resistor 31 and two temperature sensitive resistors 321 and 322 as the second temperature sensitive resistor 32. Represents the detection part. The temperature sensitive resistors 311 and 312 are arranged in a direction perpendicular to the flow 112 of the test gas in the flow path and separated from each other. Further, the temperature sensitive resistors 321 and 322 are disposed on the upstream side of the flow 112 in the flow path with respect to the temperature sensitive resistors 311 and 312.
Similar to the breath sensor 1, the two first temperature sensitive resistors and the two second temperature sensitive resistors cover the substrate removal portion from which a part of the semiconductor substrate has been removed and the surface of the insulating thin film member or Can be formed inside.

The exhalation sensor 11 can be configured with a measurement circuit 401 shown in FIG. The measurement circuit 401 includes circuits 4a1 and 4b1 and circuits 4a2 and 4b2, and includes switch circuits (switches S11, S21, S12, and S22) for switching each circuit configuration. This switch circuit is controlled as shown in FIG.
Thus, in the flow rate measurement step, the circuit 4a1 or 4a2 constitutes a bridge circuit corresponding to the fourth circuit 44, and an output Ea1 or Ea2 is obtained as the balanced output.
In the humidity measurement process, the circuits 4a1 and 4a2 constitute a bridge circuit corresponding to the first circuit 41 and the second circuit 42, and outputs Ea1 and Ea2 are obtained as balanced outputs. The circuit 4b1 or 4b2 constitutes a circuit corresponding to the third circuit 43, and an output Eb1 or Eb2 is obtained as an output thereof.
The breath sensor 11 configured in this manner has the same action as the breath sensor 1, and thus can measure the flow rate and temperature / humidity of the test gas in the same manner as the breath sensor 1.

(Embodiment 2)
The breath sensor may be configured without using the temperature sensitive resistor and the measurement circuit in common. FIG. 16 shows an embodiment in which five temperature sensitive resistors 71 to 75 are provided on one semiconductor substrate 2 installed in the flow path 111 of the test gas. In the second embodiment, the detection unit includes three temperature sensitive resistors 71, 72, and 73 as the first temperature sensitive resistors, and two temperature sensitive resistors 74 and 75 as the second temperature sensitive resistors. Is provided. Of these, the first temperature sensitive resistor (71, 72, 73) generates heat, so that it has a relatively low resistance (for example, about 100Ω to 200Ω), and the second temperature sensitive resistor (74, 75) does not generate heat. Therefore, the resistance can be relatively high (for example, about 3 kΩ to 10 kΩ). That is, the temperature sensitive resistors 71 to 73 in the second embodiment correspond to the first temperature sensitive resistor 31 in the embodiment, and the temperature sensitive resistors 74 and 75 correspond to the second temperature sensitive resistor 32 in the embodiment. To do.

Similar to the structure shown in FIG. 3, each of the temperature sensitive resistors 71 to 73, 74, and 75 is a surface of a self-supporting insulating thin film member that covers a defect portion provided in the semiconductor substrate, or is embedded in the insulating thin film member. It is preferable to be a thin film resistor.
Further, in the normally assumed flow direction 112 of the test gas in the flow path 111, the atmosphere that has passed above each of the first temperature sensitive resistors (71, 72, 73) is any other temperature sensitive. It is installed so that it does not pass over the resistor. That is, the temperature sensitive resistors 71, 72, and 73 are arranged as a group of resistors in the direction perpendicular to the flow 112 of the test gas in the flow path and spaced apart from each other. And 75 are arranged upstream of the flow 112 in the flow path with respect to the group of resistors.

FIG. 17 shows the breath sensor 12 configured by incorporating the temperature sensitive resistors 71 to 75 into the measurement circuit 402 including the first circuit 412, the second circuit 422, the third circuit 432, and the fourth circuit 442. Yes.
The first circuit 412 controls the temperature sensitive resistor 71 to a predetermined first temperature T1, and outputs an electric quantity E1 corresponding to the power consumption P1 for keeping the temperature sensitive resistor at the first temperature.
The second circuit 422 controls the temperature sensitive resistor 72 to a predetermined second temperature T2 different from the first temperature, and corresponds to the power consumption P2 for keeping the temperature sensitive resistor at the second temperature. The electric quantity E2 is output.
The third circuit 432 outputs an electric quantity E3 corresponding to the resistance value of the temperature sensitive resistor 74 having substantially the same temperature as the temperature T3 of the test gas in the flow path.
The fourth circuit 442 controls the temperature of the temperature sensing resistor 73 to a fourth temperature T4 that is higher by a predetermined temperature ΔT4 than the temperature sensing resistor 75 having substantially the same temperature as the temperature T3 of the test gas in the flow path. In addition, an electric quantity E4 corresponding to the power consumption P4 for maintaining the temperature sensitive resistor 73 at the fourth temperature is output.
The first circuit 412, the second circuit 422, the third circuit 432, and the fourth circuit 442 correspond to the first circuit 41, the second circuit 42, the third circuit 43, and the fourth circuit 44 in the previous embodiment, respectively. It is a configuration. Since each circuit is provided separately, a switch circuit (switch means) for switching to the configuration of each circuit becomes unnecessary.

Except for the points related to the above differences, the configuration, operation, and control method of the breath sensor 12 according to the second embodiment are the same as those of the breath sensor 1. That is, the breath sensor 12 includes a flow rate measuring unit that measures the flow rate of the test gas that flows through the flow path 111 by the output of at least one of the first circuit 412, the second circuit 422, and the fourth circuit 442, and the test gas. And a humidity measuring means for calculating a humidity corresponding value corresponding to the humidity of the test gas remaining in the flow path by the outputs of the first circuit 412 and the second circuit 422 after the flow of the gas is stopped. it can.
The configuration, operation, and control method of the alcohol concentration measuring device using the breath sensor 12 are the same as those of the alcohol concentration measuring device 100.

(Embodiment 3)
In addition, for example, when the temperature T3 of the test gas flowing through the flow path 111 is made substantially constant using a heater or the like, one temperature-sensitive resistor 76 as shown in FIG. The breath sensor 13 can be configured only by using such a single bridge circuit 403. In this example, when the exhalation flows, the switch S31 is turned on or off, so that the test gas is output by the output Ec as in the case of using the first circuit 41 or the second circuit 42. Can be measured. In addition, after the flow of exhalation is stopped, the switch S31 is switched between the on state and the off state, and the output Ec in each state is measured to switch between the first circuit 41 and the second circuit 42. As in the case of measurement, the humidity corresponding value (humidity) of the test gas can be calculated.

  The present invention is not limited to the embodiment described above, and various modifications can be made within the scope of the present invention depending on the purpose and application.

  1, 11, 12, 13; breath sensor, 2; detection unit, 21; semiconductor substrate, 211, 212; substrate removal unit, 22, 23; insulating thin film member, 31; first temperature-sensitive resistor, 32; Temperature sensitive resistor, 4, 401, 402, 403; measurement circuit, 41, 412; first circuit, 42, 422; second circuit, 43, 432; third circuit, 44, 442; fourth circuit, 45; Switch circuit, 5; control unit, 51; flow rate measuring means, 52; humidity measuring means, 53; sensor control means, 71 to 75, 76; temperature sensitive resistor, 100; alcohol concentration measuring device (drinking driving prevention device), 110; main flow pipe, 111; flow path, 112; flow of exhalation, 114; detection part of exhalation sensor, 115; heater, 116; constriction part, 120; alcohol concentration measurement part, 121; introduction pipe, 122; 123; pump, A1, 2; differential amplifier, Q1; transistors, R1 to R9; resistive element, S1, S2, S3; switch.

Claims (10)

An exhalation sensor for use in an alcohol concentration measuring device for measuring the alcohol concentration contained in exhaled breath directly injected,
A first temperature sensing resistor and a second temperature sensing resistor provided in one semiconductor substrate and installed in the flow path of the test gas;
A first circuit for controlling the first temperature sensitive resistor to a predetermined first temperature and outputting an amount of electricity corresponding to power consumption for maintaining the first temperature sensitive resistor at the first temperature;
The first temperature sensitive resistor is controlled to a predetermined second temperature different from the first temperature, and an electric quantity corresponding to power consumption for maintaining the first temperature sensitive resistor at the second temperature is output. A second circuit that,
A third circuit for outputting an electric quantity corresponding to a resistance value of the second temperature sensing resistor having substantially the same temperature as the temperature of the test gas in the flow path;
Controlling the temperature of the first temperature sensitive resistor to a fourth temperature that is higher by a predetermined temperature than the second temperature sensitive resistor having substantially the same temperature as the temperature of the test gas in the flow path; and A fourth circuit that outputs an amount of electricity corresponding to power consumption for maintaining the first temperature sensitive resistor at the fourth temperature;
With
The breath sensor according to claim 1, wherein the first circuit, the second circuit, and the fourth circuit are configured by switching a configuration of one bridge circuit by a switch unit. A flow rate measuring means for measuring a flow rate of the test gas flowing through the flow path by an output of at least one of the first circuit, the second circuit, and the fourth circuit;
After the flow of the test gas is stopped, the first circuit and the second circuit are switched, and a humidity-corresponding value corresponding to the humidity of the test gas remaining in the flow path is calculated by each output thereof. A humidity measuring means,
An exhalation sensor according to claim 1.   The first temperature sensitive resistor and the second temperature sensitive resistor are respectively formed on the surface or inside of an insulating thin film member that covers and self-supports a substrate removal portion from which a part of the semiconductor substrate is removed. The breath sensor according to 1 or 2.   The breath sensor according to any one of claims 1 to 3, wherein the first temperature sensitive resistor is disposed downstream of the second temperature sensitive resistor in the flow path. An alcohol concentration measuring device comprising the breath sensor according to any one of claims 2 to 4,
The flow rate measuring means further determines an appropriate flow rate when detecting that the gas to be detected having a flow rate in a predetermined range continuously flows for a predetermined time,
The humidity measuring means further determines the appropriate humidity when the humidity corresponding value is within a predetermined range,
After prompting the exhalation, if the flow rate of the test gas is measured by the flow rate measuring means and determined to be the proper flow rate, the stop of the insufflation is urged, and the insufflation is stopped When the humidity measurement value is calculated by the humidity measuring means and determined as the appropriate humidity, a sensor that enables measurement of the alcohol concentration of the test gas introduced from the flow path An alcohol concentration measuring apparatus comprising a control means. An exhalation sensor for use in an alcohol concentration measuring device for measuring the alcohol concentration contained in exhaled breath directly injected,
One or two or more first temperature sensing resistors and one or two or more second temperature sensing resistors provided on one semiconductor substrate and installed in the flow path of the test gas;
A first circuit that controls any one of the first temperature sensitive resistors to a predetermined first temperature and outputs an amount of electricity corresponding to power consumption for maintaining the first temperature sensitive resistor at the first temperature. When,
Electricity corresponding to power consumption for controlling any of the first temperature sensitive resistors to a predetermined second temperature different from the first temperature and maintaining the first temperature sensitive resistors at the second temperature. A second circuit for outputting a quantity;
A third circuit for outputting an electric quantity corresponding to a resistance value of any one of the second temperature sensitive resistors set to be substantially the same as the temperature of the test gas in the flow path;
The temperature of any one of the first temperature sensing resistors is higher by a predetermined temperature than any one of the second temperature sensing resistors that is substantially the same as the temperature of the test gas in the flow path. A fourth circuit for controlling the temperature to 4 and outputting an amount of electricity corresponding to power consumption for maintaining the first temperature-sensitive resistor at the fourth temperature;
A breath sensor characterized by comprising: A flow rate measuring means for measuring a flow rate of the test gas flowing through the flow path by an output of at least one of the first circuit, the second circuit, and the fourth circuit;
Humidity measuring means for calculating a humidity corresponding value corresponding to the humidity of the test gas remaining in the flow path by the outputs of the first circuit and the second circuit after the flow of the test gas is stopped. When,
An exhalation sensor according to claim 6.   7. The first temperature sensitive resistor and the second temperature sensitive resistor are formed on the surface or inside of an insulating thin film member that covers and self-supports a substrate removal portion from which a part of the semiconductor substrate is removed. Or the breath sensor of 7.   Two or more first temperature sensitive resistors are arranged as a group of resistors in a direction perpendicular to the flow of the test gas in the flow path and spaced apart from each other, and the second temperature sensitive resistors are arranged. The breath sensor according to any one of claims 6 to 8, wherein the resistor is disposed upstream of the flow in the flow path with respect to the group of resistors. An alcohol concentration measuring device comprising the breath sensor according to any one of claims 7 to 9,
The flow rate measuring means further determines an appropriate flow rate when detecting that the gas to be detected having a flow rate in a predetermined range continuously flows for a predetermined time,
The humidity measuring means further determines the appropriate humidity when the humidity corresponding value is within a predetermined range,
After prompting the exhalation, if the flow rate of the test gas is measured by the flow rate measuring means and determined to be the proper flow rate, the stop of the insufflation is urged, and the insufflation is stopped When the humidity measurement value is calculated by the humidity measuring means and determined as the appropriate humidity, a sensor that enables measurement of the alcohol concentration of the test gas introduced from the flow path An alcohol concentration measuring apparatus comprising a control means.

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