Expiration sensor, gas sensor, and expiration sensing method

Abstract

To correct an influence of disturbance in measurement.SOLUTION: An expiration sensor which senses an expiration generated by breathing includes: a light emitting unit which emits light toward a path through which the expiration passes; a first light receiving unit which receives at least a part of the light emitted from the light emitting unit and outputs a first light reception signal according to a light reception result; and an operating unit which performs an operation on the first light reception signal. The operating unit calculates a baseline of a waveform based on a frequency component of the first light reception signal lower than a first cut-off frequency that is set, and senses the expiration based on a signal obtained by removing the baseline from the first light reception signal.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a breath sensor, a gas sensor, and a breath detection method. [Background technology]

[0002] 2. Description of the Related Art Conventionally, measuring devices for measuring respiratory gases, gas concentrations, or respiratory rates are known (see, for example, Patent Documents 1 to 3). [Patent documents] Patent Document 1 Patent No. 5351583 Patent Document 2: JP 2022-3321 A Patent Document 3 Patent No. 3627243 Summary of the Invention [Problem to be solved by the invention]

[0003] It is preferable to correct the effects of disturbances in the measurement. [Means for solving the problem]

[0004] In a first aspect of the present invention, there is provided a breath sensor that detects breath generated by breathing. The breath sensor includes a light emitting unit that irradiates light toward a path through which the breath passes, a first light receiving unit that receives at least a portion of the light irradiated by the light emitting unit and outputs a first light receiving signal according to the light receiving result, and a calculation unit that performs calculations on the first light receiving signal. The calculation unit calculates a baseline of the waveform based on a frequency component of the first light receiving signal that is lower than a set first cutoff frequency, and detects breath based on a signal obtained by removing the baseline from the first light receiving signal.

[0005] The calculation unit may calculate at least one of the period and length of breathing.

[0006] In any of the breath sensors described above, the first cutoff frequency may be set in response to a change in the signal value of the first received light signal.

[0007] In any of the above breath sensors, the calculation unit may set the first cutoff frequency when the signal value of the first light receiving signal for which the baseline value is calculated increases relative to a past signal value in the time waveform of the first light receiving signal to be higher than the first cutoff frequency when the signal value decreases relative to a past signal value.

[0008] In any of the above breath sensors, the calculation unit may set the first cutoff frequency when the signal value of the first light receiving signal for which the baseline value is calculated has increased by 20% or more compared to a past signal value in the time waveform of the first light receiving signal, higher than the first cutoff frequency when the signal value has decreased by 20% or more compared to a past signal value.

[0009] In any of the above breath sensors, the calculation unit may set the first cutoff frequency when the signal value of the first light receiving signal for which the baseline value is calculated increases relative to the signal value at the immediately preceding timing in the time waveform of the first light receiving signal to be 10 times or more higher than the first cutoff frequency when the signal value decreases relative to the immediately preceding signal value.

[0010] In any of the above breath sensors, the calculation unit may set the first cutoff frequency when the signal value of the first light receiving signal for which the baseline value is calculated has increased by 20% or more compared to the signal value at the immediately preceding timing in the time waveform of the first light receiving signal, to be 10 times or more higher than the first cutoff frequency when the signal value has decreased by 20% or more compared to the immediately preceding signal value.

[0011] In any of the breath sensors described above, the first cutoff frequency may be 3 Hz or less.

[0012] Any of the above breath sensors may further include a second light receiving unit that receives light emitted by the light emitting unit that has not passed through the path through which the breath passes and outputs a second light receiving signal according to the light receiving result. The calculation unit may correct the first light receiving signal based on a signal value of the second light receiving signal.

[0013] In any of the above breath sensors, the calculation unit may generate the corrected first light receiving signal using a frequency component of the second light receiving signal lower than a set second cutoff frequency and a frequency component of the first light receiving signal lower than a set third cutoff frequency. The second cutoff frequency may be lower than the third cutoff frequency.

[0014] Any of the breath sensors may further include an optical filter that is disposed on the optical path of light between the light emitting unit and the first light receiving unit and limits the wavelength of light that is incident on the first light receiving unit.

[0015] In a second aspect of the present invention, there is provided a gas sensor for detecting a target gas. The gas sensor includes a light emitting unit that irradiates light toward a path through which the target gas passes, a first light receiving unit that receives at least a portion of the light irradiated by the light emitting unit and outputs a first light receiving signal according to the light receiving result, and a calculation unit that performs calculations on the first light receiving signal. The calculation unit calculates a baseline of a waveform of the first light receiving signal based on a frequency component of the first light receiving signal that is lower than a set first cutoff frequency, and detects the target gas based on a signal obtained by removing the baseline from the first light receiving signal.

[0016] In a third aspect of the present invention, there is provided a breath detection method for detecting breath generated by breathing. The breath detection method includes a light emitting step in which a light emitting unit irradiates light toward a path through which the breath passes, a first light receiving step in which a first light receiving unit receives at least a part of the light irradiated in the light emitting step, a first output step in which the first light receiving unit outputs a first light receiving signal according to a light receiving result in the first light receiving step, and a calculation step in which a calculation unit performs a calculation on the first light receiving signal output in the first output step. The calculation step includes a calculation step in which the calculation unit calculates a baseline of a waveform of the first light receiving signal based on a frequency component of the first light receiving signal that is lower than a first cutoff frequency that is set, and a detection step in which the calculation unit detects breath based on a signal obtained by removing the baseline calculated in the calculation step from the first light receiving signal.

[0017] The above summary of the invention does not list all of the necessary features of the present invention. Also, subcombinations of these features may also be inventions. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram showing an example of a breath sensor 10 according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram illustrating an example of signal processing. [Diagram 3] FIG. 13 is a diagram illustrating an example of calculation of a baseline. [Figure 4A] FIG. 13 shows an example of the results of using a constant first cutoff frequency in baseline calculation. [Figure 4B] 4B is a diagram showing an example of a determination signal obtained by calculating a ratio of received light signals and a difference between baseline calculation values ​​from FIG. 4A. FIG. [Figure 5A] FIG. 13 is a diagram showing an example of the result of changing the first cutoff frequency depending on the magnitude relationship of the immediately preceding signal value in baseline calculation. [Figure 5B] 5B is a diagram showing an example of a determination signal calculated from the light receiving signal ratio and the baseline shown in FIG. 5A. FIG. [Figure 6A] 11 is a diagram showing an example of a case where signal processing is performed using the same cutoff frequency for a first received light signal and a second received light signal. FIG. [Figure 6B] 6B is a diagram showing an example of a light receiving signal ratio calculated from the first light receiving signal and the second light receiving signal shown in FIG. 6A. FIG. [Figure 7A] 11 is a diagram showing an example of a case where signal processing is performed using different cutoff frequencies for a first received light signal and a second received light signal. FIG. [Figure 7B] 7B is a diagram showing an example of a ratio between the first light receiving signal and the second light receiving signal in FIG. 7A. FIG. [Figure 8] FIG. 2 is a diagram showing another example of the breath sensor 10 according to an embodiment of the present invention. [Figure 9A] 2 is a diagram showing an example of the configuration of a light-emitting unit 16. FIG. [Figure 9B]FIG. 1 is a diagram showing an example of a gas sensor 11 according to an embodiment of the present invention. [Figure 10] 1 is a flowchart illustrating an example of a breath detection method according to an embodiment of the present invention. [Figure 11] 11 is a flowchart illustrating another example of a breath detection method according to an embodiment of the present invention. [Figure 12] FIG. 1 is a schematic diagram illustrating an example of a breath detection system 100 according to an embodiment of the present invention. [Figure 13] FIG. 1 is a functional block diagram illustrating an example of a breath detection system 100. [Figure 14] 3A to 3C are diagrams illustrating an example of a state of a main body section 102. [Figure 15] 11A and 11B are diagrams illustrating other examples of the state of the main body portion 102. [Figure 16] FIG. 2 is a diagram illustrating an example of the configuration of a state detection unit 150. [Figure 17] FIG. 1 is a diagram showing an example of a display device 300 according to an embodiment of the present invention. [Figure 18] 2 is a diagram showing an example of an operator 310 of the display unit 210. FIG. [Figure 19] FIG. 1 is a block diagram showing an example of a display device 300 according to an embodiment of the present invention. [Figure 20] 1 is a diagram showing an example of a situation in which an operator 310 is using a device 400. FIG. [Figure 21] 1 is a diagram showing an example of the relationship between the CO2 (carbon dioxide) concentration in the exhaled breath of an operator 310 and the exhaled breath volume of the operator 310. FIG. [Figure 22] 4 is a flowchart illustrating an example of a display method according to an embodiment of the present invention. [Figure 23] FIG. 22 illustrates an example of a computer 2200 in which the breath detection system 100 or the display device 300 according to an embodiment of the present invention may be implemented in whole or in part. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention. In this specification, the same parts in each figure are given the same reference numerals, and the description may be omitted. In addition, some configurations may not be illustrated for convenience of explanation.

[0020] In this specification, technical matters may be explained using an orthogonal coordinate system of X-axis, Y-axis, and Z-axis. The orthogonal coordinate system merely specifies the relative positions of components, and does not limit specific directions. For example, the Z-axis direction does not limit the height direction relative to the ground.

[0021] FIG. 1 is a diagram showing an example of a breath sensor 10 according to an embodiment of the present invention. The breath sensor 10 detects breath generated by breathing. The breath sensor 10 includes a light emitting unit 16, a first light receiving unit 18, and a calculation unit 20. The light emitting unit 16, the first light receiving unit 18, and the calculation unit 20 may be attached to a support member 30. In this example, the light emitting unit 16 is attached to one of the support members 30 facing each other, and the first light receiving unit 18 and the calculation unit 20 are attached to the other. In this example, a plane parallel to the main surface of the support member 30 is defined as an XY plane, and a direction perpendicular to the main surface of the support member 30 is defined as a Z-axis direction.

[0022] The breath sensor 10 is an NDIR (non-dispersive infrared) sensor that utilizes a specific absorption wavelength of carbon dioxide contained in the breath. The light emitting unit 16 irradiates light 14 toward a path 12 through which the breath passes. The light emitting unit 16 is, for example, an IR-LED. The light 14 may be infrared light, or may be light that includes at least the absorption wavelength of carbon dioxide. A portion of the light 14 passes through the path 12 and enters a first light receiving unit 18. A portion of the light 14 enters a second light receiving unit 22, which will be described later.

[0023] The first light receiving section 18 receives at least a part of the light 14 emitted by the light emitting section 16, and outputs a first light receiving signal according to the light receiving result to the calculation section 20. The first light receiving section 18 is, for example, a photodiode.

[0024] The calculation unit 20 performs calculations on the first light receiving signal. The calculation unit 20 is, for example, an IC. Since the amount of light received at the absorption wavelength of carbon dioxide decreases as carbon dioxide absorbs the light 14, the calculation unit 20 can calculate the carbon dioxide concentration or a value corresponding to the concentration from the first light receiving signal.

[0025] The breath sensor 10 may further include a thermometer. The calculation unit 20 may receive temperature information of the breath sensor 10 from the thermometer. By correcting the first light receiving signal based on the temperature information, the calculation unit 20 can more accurately calculate the carbon dioxide concentration or a value corresponding to the concentration from the first light receiving signal.

[0026] The breath sensor 10 may include a second light receiving unit 22. The configurations of the light emitting unit 16 and the second light receiving unit 22 will be described later. The second light receiving unit 22 receives the light 14 emitted by the light emitting unit 16 that has not passed through the path 12 through which the breath passes, and outputs a second light receiving signal according to the light receiving result. The second light receiving signal may be output to the calculation unit 20. The calculation unit 20 may correct the first light receiving signal using the signal value of the second light receiving signal. The calculation unit 20 may generate a signal obtained by dividing the signal value of the first light receiving signal by the signal value of the second light receiving signal as the detection signal. By providing the second light receiving unit 22, it is possible to correct output fluctuations due to changes in the amount of light of the light emitting unit 16 and temperature.

[0027] The breath sensor 10 may further include an optical filter 24 disposed on the optical path of the light 14 between the light emitting unit 16 and the first light receiving unit 18. In this example, the optical filter 24 is provided on the surface of the first light receiving unit 18. The optical filter 24 limits the wavelength of the light 14 incident on the first light receiving unit 18. One example of the optical filter 24 is a bandpass filter.

[0028] In general, the sensitivity of the first light receiving section 18 changes due to the influence of temperature. In a sensitivity curve with the horizontal axis representing the wavelength of light and the vertical axis representing the sensitivity of the first light receiving section 18, the influence of temperature appears as a shift of the sensitivity curve along the horizontal axis. On the other hand, the sensitivity curve has a wavelength range in which the sensitivity value is almost flat. By using the optical filter 24 to allow only light of wavelengths in that wavelength range to enter the first light receiving section 18, the influence on sensitivity can be suppressed even if the temperature of the first light receiving section 18 changes.

[0029] FIG. 2 is a diagram showing an example of signal processing in the calculation unit 20. In FIG. 2 and the following figures, the first light receiving signal is represented as IR1, and the second light receiving signal is represented as IR2. The horizontal axis of FIG. 2 indicates time, and the vertical axis indicates the value of the ratio of the intensities of the first light receiving signal and the second light receiving signal. In this specification, the ratio of the intensities of the first light receiving signal and the second light receiving signal may be referred to as the light receiving signal ratio. Also, the intensity of the first light receiving signal may be simply referred to as the first light receiving signal, and the intensity of the second light receiving signal may be simply referred to as the second light receiving signal. As described above, by dividing the first light receiving signal by the second light receiving signal, it is possible to correct the change in the amount of light of the light emitting unit 16 and the output fluctuation due to temperature.

[0030] Here, the first light receiving signal and the second light receiving signal may be values ​​that have been corrected by the above-mentioned temperature information in the calculation unit 20. Unless the first light receiving unit 18 and the second light receiving unit 22 have the same characteristics, the output fluctuations can be corrected more accurately by temperature-compensating the light receiving signals.

[0031] In the following figures, the embodiment will be described using the light receiving signal ratio between the first light receiving signal and the second light receiving signal, but it is not essential to use the second light receiving signal. Instead of the light receiving signal ratio, the signal value of the first light receiving signal may be used. In this case, the term "light receiving signal ratio" may be read as "first light receiving signal." In this specification, even if processing is performed on the light receiving signal ratio, the same processing may be performed on the first light receiving signal, and even if processing is performed on the first light receiving signal, the same processing may be performed on the light receiving signal ratio.

[0032] The calculation unit 20 obtains the ratio of the input first and second light receiving signals, and performs signal processing on the light receiving signal ratio. In FIG. 2, noise is removed. The dotted line in the figure indicates the light receiving signal ratio before noise removal, and the solid line indicates the light receiving signal ratio after noise removal. The calculation unit 20 performs noise removal using a low-pass filter, for example. The amount of light received by the first light receiving unit 18 decreases due to absorption of carbon dioxide, so the light receiving signal ratio decreases when exhalation is detected. In addition, since exhalation quickly diffuses into the air, the light receiving signal ratio increases (recovers) immediately after decreasing. The fluctuation in the light receiving signal ratio around 10 to 20 seconds in the figure corresponds to breathing. One valley in the light receiving signal ratio corresponds to one breath. In the example of FIG. 2, five valleys appear in the waveform of the light receiving signal ratio, so the light receiving signal ratio for five breaths is shown.

[0033] Fig. 3 is a diagram showing an example of calculation of the baseline. The axes in Fig. 3 are the same as those in Fig. 2. The solid line in the figure indicates the received light signal ratio after noise processing. The calculation unit 20 calculates the baseline of the waveform of the first received light signal from the received light signal ratio. The dotted line in the figure indicates the calculated baseline.

[0034] The baseline refers to a signal waveform caused by factors (disturbances) other than carbon dioxide contained in the breath. The baseline is a waveform in which the components caused by the concentration of carbon dioxide are reduced or removed from the waveform shown by the solid line in FIG. 3. The baseline may include a component of the intensity of the light 14 emitted by the light-emitting unit 16 and a fluctuation component caused by factors other than the change in the concentration of carbon dioxide. When the breath sensor 10 detects breath, the temperature of the light-emitting unit 16 and the first light-receiving unit 18 may change depending on the temperature of the breath, causing the characteristics to change. The baseline may be a signal waveform that includes the influence of such a change in characteristics and does not include the influence of carbon dioxide. The baseline caused by a disturbance whose frequency is out of sync with the breathing cycle may also include the influence of humidity, deterioration of elements, etc., but in this specification, it is assumed to mainly include the fluctuation caused by the temperature of the breath.

[0035] The calculation unit 20 may calculate the baseline based on the light receiving signal ratio. Since there is a correlation between the light receiving signal ratio and the effect of temperature due to exhalation, this allows the effect of temperature due to exhalation to be appropriately reflected. The baseline calculation value in FIG. 3 is calculated from the light receiving signal ratio and therefore varies according to the breathing cycle, but this represents the effect of temperature due to exhalation. Parameters for baseline calculation may be determined experimentally so that changes in the light receiving signal ratio due to factors other than carbon dioxide are represented. An example of the parameter is a coefficient b0, which will be described later.

[0036] The calculation unit 20 may calculate the baseline by removing disturbance frequency components that are out of frequency with respect to the respiratory cycle from the time waveform of the light receiving signal ratio. As an example, the calculation unit 20 calculates the baseline by filtering expressed by infinite impulse response (IIR). Table 1 shows an example of the process of calculating the baseline in IIR filtering. [Table 1]

[0037] In the table, x represents the signal value of the received signal ratio, and y represents the calculated baseline value. b0 is the filter coefficient. The number after x and y represents the sampling point n. Table 1 shows up to n=3.

[0038] The calculation unit 20 calculates the baseline value yn for each signal value xn of the light receiving signal ratio. As shown in Table 1, the calculated baseline value yn is calculated by multiplying the corresponding signal value xn by a coefficient b0 and the calculated value yn-1 of the previous baseline by (1-b0). In other words, the coefficient b0 determines the percentage of the corresponding signal value to be reflected in the calculated value of the previous baseline. The coefficient b0 takes a value of 0 or more and 1 or less. When the coefficient b0 is made larger, the corresponding signal value is more reflected, and the baseline can easily follow the fluctuation of the signal value. In the example of Table 1, the calculated value yn of the baseline reflects the value of one previous baseline yn-1, but in other examples, the calculated value yn of the baseline may reflect the values ​​of multiple previous baselines.

[0039] The calculation unit 20 may calculate the baseline using a moving average filter (MA) shown in the following formula 1. In formula 1, Y n is the calculated value, and X n is the signal value, M is the number of intervals, and F s is the sampling frequency, and f c is the cutoff frequency. In the calculation method using the moving average, the calculation unit 20 calculates the average value for each certain interval while shifting the interval. The number of intervals M is the number of the intervals.

number

[0040] The calculation unit 20 may calculate the baseline using a weighted moving average filter (WMA) shown in the following formula 2. In formula 2, W i is the weighting. M is the number of intervals, as in Equation 1.

number

[0041] The calculation section 20 may calculate the baseline using a finite impulse response (FIR) filter shown in the following formula 3. In formula 3, bi is a filter coefficient, and M is the number of sections, as in formula 1.

number

[0042] The calculation unit 20 may calculate the baseline using a Butterworth filter shown in the following formula 4. In formula 4, N is the filter order, and s is the complex frequency in the Laplace transform. If σ is the real part, ω is the frequency, and j is the imaginary unit, then s is expressed as the sum of σ and jω.

number

[0043] The calculation unit 20 may calculate the baseline based on the signal value when the signal fluctuation is small during a predetermined period. The case when the signal fluctuation is small is, for example, data during a time when breathing is not taking place. The predetermined period is, for example, a period covering five breaths in FIG. 2.

[0044] At least one of an upper limit and a lower limit may be set for the baseline.Which of Table 1 and Formulas 1 to 4 is used to calculate the baseline may be changed depending on the signal value or the environmental temperature.

[0045] Here, the calculation of the immediately preceding baseline is not limited to calculating the baseline of xn by xn-1. Any baseline calculation method that is difficult to follow the respiratory signal may be used. For example, for xn, the baseline calculation may be performed using all signals from xn-1 to further prior data xn-m, where m is a natural number. For example, if data is acquired every 0.1 seconds, the baseline calculation of the signal xn may be performed using the data of signals xn-1, xn-2, and xn-3 with m=3. The immediately preceding range may be determined so that it is difficult to follow the respiratory signal but can follow slower temperature fluctuations. The calculation of the baseline may be performed based on the light receiving signal ratio in the past Tn, or based on the light receiving signal ratio in a specific period shorter than the respiratory cycle in the past Tn.

[0046] The calculation unit 20 removes the baseline from the light receiving signal ratio. Removing the baseline may mean subtracting the baseline value at each time from the signal value at that time. By calculating and removing the baseline, it is possible to correct changes in the signal value due to factors other than carbon dioxide contained in the exhaled breath, and more accurate measurements can be performed. In this specification, the signal after removing the baseline from the light receiving signal ratio may be referred to as a determination signal.

[0047] The calculation unit 20 detects exhalation based on the judgment signal. When the value of the judgment signal is lower than the judgment threshold, the calculation unit 20 may determine that exhalation has been detected. The judgment threshold may be set in advance. The calculation unit 20 may calculate at least one of the breathing cycle or length. The calculation unit 20 may calculate the breathing cycle or length during a period in which the value of the judgment signal is lower than the judgment threshold. The calculation unit 20 may determine the breathing length as one continuous period in which the value of the judgment signal is lower than the judgment threshold. The calculation unit 20 may calculate the sum of one continuous period in which the value of the judgment signal is higher than the judgment threshold and one continuous period in which the value of the judgment signal is lower than the judgment threshold as the breathing cycle. The calculation unit 20 may calculate an average value within a predetermined measurement period as the breathing cycle or length. By calculating the breathing cycle or length, it is possible to determine whether the person breathing is excited or relaxed. When measuring the cycle or length of breathing, it is sufficient to compare the value of the determination signal with the determination threshold, and it is not necessary to calculate the amplitude of the determination signal, and the measurement accuracy of the value of the determination signal does not need to be high.

[0048] Here, setting the coefficient b0 in the infinite impulse response corresponds to removing frequency components equal to or higher than a predetermined frequency from the signal value in calculating the baseline. If the predetermined frequency is the first cutoff frequency, the relationship between the first cutoff frequency and the coefficient b0 is expressed by the following formula 5. In the formula, a1=b0-1.

[0049]

number

[0050] The calculation section 20 may calculate the baseline based on the frequency components of the time waveform of the light receiving signal ratio that are lower than the first cutoff frequency that is set. By setting a coefficient b0 in the infinite impulse response, the baseline can be calculated based on the frequency components of the light receiving signal ratio that are lower than the first cutoff frequency. Specific examples of the coefficient b0 and the first cutoff frequency will be described later.

[0051] FIG. 4A is a diagram showing an example of the result of using a constant first cutoff frequency in the baseline calculation. The axis of FIG. 4A and the solid and dotted lines in the diagram are the same as those in FIG. 3. In this example, the baseline calculation is performed by setting the first cutoff frequency constant for the baseline value yn at each time. For example, in the example of Table 1, b0 is a constant value for all n. In FIG. 4A, the baseline does not track well when the light receiving signal ratio is increasing. Therefore, during the period when breathing is continuous, the baseline does not return to the original level (IR1 / IR2=about 1 to 1.01) and is at a relatively low level. Also, immediately after the period when breathing is continuous ends, there are some points where the baseline is lower than the light receiving signal ratio.

[0052] FIG. 4B is a diagram showing an example of a determination signal obtained by taking the difference between the light receiving signal ratio and the baseline calculation value from FIG. 4A. Since the determination signal indicates a signal component due to exhalation, the determination signal when exhalation is not present ideally coincides with the reference point (IR1 / IR2=0). Furthermore, the determination signal when exhalation is present ideally becomes smaller than the reference point. In FIG. 4B, a part of the determination signal is located above (on the positive side) the reference point (IR1 / IR2=0). The determination signal is shifted upward. This is thought to be due to poor tracking of the baseline when the light receiving signal ratio increases, resulting in the baseline being evaluated as smaller than it actually is.

[0053] The dashed line in the figure indicates the judgment threshold. As an example, it is judged that exhalation is detected when the signal value is lower than the judgment threshold. In FIG. 4B, only a part of the signal value fluctuation due to exhalation is below the judgment threshold, and some breathing may not be detected. Therefore, it is preferable to calculate the breathing cycle, etc. more accurately.

[0054] FIG. 5A is a diagram showing an example of the result of changing the first cut-off frequency based on the magnitude relationship of the immediately preceding signal value in baseline calculation. The first cut-off frequency may be set according to the change in the signal value of the received light signal ratio. In this example, the calculation unit 20 changes the first cut-off frequency according to the change in the signal value of the received light signal ratio. The calculation unit 20 in this example sets the first cut-off frequency when the signal value of the received light signal ratio for which the baseline value is to be calculated increases with respect to the signal value at the immediately preceding timing in the time waveform of the received light signal ratio to be higher than the first cut-off frequency when it decreases with respect to the immediately preceding signal value.

[0055] Using the symbols in Table 1, the first cut-off frequency when xn > xn-1 is set higher than the first cut-off frequency when xn < xn-1. The calculation unit 20 may set the first cut-off frequency higher by making the coefficient b0 when xn > xn-1 larger than the coefficient b0 when xn < xn-1. By increasing the first cut-off frequency, relatively high frequency components in the signal waveform of the first light emission signal can be reflected in the baseline. Therefore, the followability of the baseline when the signal value of the first light emission signal increases is improved. In FIG. 5A, the baseline follows well the increase in the signal value of the first light emission signal. Therefore, during the period when breathing is continuous and in the period immediately after that, the baseline returns closer to the original value (1 to 1.01) compared to the example of FIG. 4A.

[0056] When breath flows into the breath sensor 10, after carbon dioxide is detected, the temperature of the element rises due to the temperature of the breath. For this reason, it is considered that the influence of the temperature characteristics of the element appears in the time waveform of the baseline. Since the temperature of the element changes in synchronization with breathing, a valley portion synchronized with breathing appears in the time waveform of the baseline as shown in FIG. 5A. It is considered that the influence of the temperature of the breath appears later than the detection of carbon dioxide. By setting the first cutoff frequency described above, during the period when the signal value of the light receiving signal ratio is decreasing, the baseline calculation value is less likely to follow the fluctuation of the signal value due to the detection of carbon dioxide, so that the baseline calculation value is less likely to include the influence of carbon dioxide and appropriately reflects the influence of the temperature of the breath.

[0057] The calculation unit 20 may set the first cutoff frequency higher when the signal value of the light receiving signal ratio of the target for calculating the baseline value increases from the past signal value in the time waveform of the light receiving signal ratio than the first cutoff frequency when it decreases from the past signal value. The past signal value may be the average value of the light receiving signal ratio in a period shorter than the respiratory cycle with the immediately preceding light receiving signal ratio as the end of the period, may be the signal value of any light receiving signal ratio in the period, or may be the signal value of all light receiving signal ratios in the period. Using the symbols in Table 1, as an example, the first cutoff frequency may be set higher when xn is higher than the average value of xn-1, xn-2, and xn-3 than the first cutoff frequency when xn is lower than the average value. The calculation unit 20 may set the first cutoff frequency higher when the signal value of the light receiving signal ratio of the target for calculating the baseline value increases by 20% or more from the past signal value in the time waveform of the light receiving signal ratio than the first cutoff frequency when it decreases by 20% or more from the past signal value.

[0058] FIG. 5B is a diagram showing an example of a determination signal calculated from the received light signal ratio and the baseline shown in FIG. 5A. In FIG. 5B, excluding minute noise components, the determination signal is positioned below the reference point (IR1 / IR2 = 0) at all times. The dashed-dotted line in the figure indicates the determination threshold as in FIG. 4B. According to this example, the shift of the determination signal can be suppressed, and respiration can be detected more accurately, and the period and length of respiration can be calculated.

[0059] When the signal value of the received light signal ratio for which the operation unit 20 calculates the baseline value increases with respect to the signal value at the immediately preceding timing in the time waveform of the received light signal ratio, the operation unit 20 may set the first cut-off frequency to be 10 times or more higher than the first cut-off frequency when the signal value decreases with respect to the immediately preceding signal value. As an example, the first cut-off frequency when xn>xn−1 may be 1 Hz or more (for example, about 1.8 Hz (coefficient b0 = 0.24)), and the first cut-off frequency when xn<xn−1 may be 0.1 Hz or less (for example, about 0.06 Hz (coefficient b0 = 0.01)). Thereby, the followability of the baseline is further improved. The magnification may be 2 times or more, may be 5 times or more, and may be 20 times or more. The first cut-off frequency may be 3 Hz or less. Note that the signal value at the immediately preceding timing may be the above-described past signal value. When the signal value of the received light signal ratio for which the operation unit 20 calculates the baseline value increases by 20% or more with respect to the signal value at the immediately preceding timing in the time waveform of the received light signal ratio, the operation unit 20 may set the first cut-off frequency to be 10 times or more higher than the first cut-off frequency when the signal value decreases by 20% or more with respect to the immediately preceding signal value.

[0060] FIG. 6A is a diagram showing an example of a case where signal processing is performed using the same cutoff frequency for each of the first and second received light signals. The horizontal axis of FIG. 6A indicates time, the left vertical axis indicates the signal strength (%) of the first received light signal (IR1), and the right vertical axis indicates the signal strength (%) of the second received light signal (IR2). The first received light signal is indicated by a solid line, and the second received light signal is indicated by a dotted line. The reference of the signal strength may be the signal value when no breath is present. The signal strength in this example is a value that indicates the value of each signal as a percentage when the value of each signal when no breath is present is normalized to 100% (reference value). The difference between the reference value and the signal strength is the fluctuation rate. In this example, it is expressed as the fluctuation rate (%) = reference value (100%) - signal strength (%). The more the signal strength deviates from 100%, the larger the fluctuation rate becomes, indicating a large fluctuation from the reference value. However, the reference value may be a value other than 100%.

[0061] The first and second received light signals in Fig. 6A are subjected to signal processing to remove frequency components equal to or higher than a predetermined frequency from the signal values. The predetermined frequency of the second received light signal is set as the second cutoff frequency, and the predetermined frequency of the first received light signal is set as the third cutoff frequency. In this example, the second cutoff frequency and the third cutoff frequency are equal.

[0062] A typical breathing frequency is about 0.25 Hz under normal conditions and about 0.42 Hz under tachypnea. The value of the third cutoff frequency is set higher than 0.42 Hz, and fluctuations in the first light receiving signal due to breathing can be seen. Meanwhile, the second light receiving signal also fluctuates at a period close to that of the first light receiving signal. The second light receiving unit 22 that outputs the second light receiving signal receives light 14 that has not passed through the path 12 through which the exhaled air passes, and this is considered to be due to the influence of the temperature of the exhaled air. This tendency becomes stronger especially when the environmental temperature is low and the temperature difference between the environmental temperature and the exhaled air is large.

[0063] FIG. 6B is a diagram showing an example of a light receiving signal ratio calculated from the first light receiving signal and the second light receiving signal shown in FIG. 6A. The horizontal axis of FIG. 6B is time, and the vertical axis is the light receiving signal ratio (%). The light receiving signal ratio has a waveform with no periodicity compared to the first light receiving signal in FIG. 6A. In other words, the fluctuation of the second light receiving signal cancels out the fluctuation of the first light receiving signal. As a result, the accuracy of breathing detection deteriorates.

[0064] Fig. 7A is a diagram showing an example of a case where signal processing is performed using different cutoff frequencies for the first and second received light signals. Fig. 7A differs from Fig. 6A in that the second cutoff frequency and the third cutoff frequency are different. The other parts are the same as Fig. 6A. Fig. 7B is a diagram showing an example of the received light signal ratio of Fig. 7A. Fig. 7B is the same as Fig. 6B except that the signal value of Fig. 7A is used.

[0065] The calculation unit 20 generates a corrected first light receiving signal using a frequency component of the second light receiving signal lower than the set second cutoff frequency and a frequency component of the first light receiving signal lower than the set third cutoff frequency. In this example, the corrected first light receiving signal is a light receiving signal ratio.

[0066] The second cutoff frequency in this example is lower than the third cutoff frequency. Therefore, the period of the second light receiving signal close to the period of the first light receiving signal is removed. As a result, a light receiving signal ratio reflecting the breathing period is obtained in FIG. 7B. The second cutoff frequency may be lower than 0.25 Hz, which is the normal breathing frequency. The third cutoff frequency may be higher than 0.42 Hz, which is the frequency during polypnea. The calculation unit 20 may perform the above-mentioned baseline calculation based on the light receiving signal ratio.

[0067] The calculation unit 20 may generate the corrected first received light signal by changing the filter time in the above formula 4 instead of the cutoff frequency. When performing noise removal, the calculation unit 20 may change the type of low-pass filter. The calculation unit 20 may change the attenuation slope of the low-pass filter. The attenuation slope is an index indicating the steepness of signal attenuation at the transition portion from the pass band to the stop band of the filter.

[0068] FIG. 8 is a diagram showing another example of the breath sensor 10 according to an embodiment of the present invention. In the breath sensor 10 of this example, the light emitting unit 16, the first light receiving unit 18, and the calculation unit 20 are attached to the same support member 30. The breath sensor 10 of this example has a mirror 32. Between the support member 30 and the mirror 32 is the path 12 through which the breath passes. In the breath sensor 10 of this example, a part of the light 14 emitted by the light emitting unit 16 is reflected by the mirror 32, and the first light receiving unit 18 receives the reflected light 14. The other parts may be the same as the breath sensor 10 of FIG. 1. With such a configuration, the breath sensor 10 can be made smaller in size.

[0069] 9A is a diagram showing a configuration example of the light-emitting unit 16. The light-emitting unit 16 of this example has a substrate 40, a light-emitting element 44, and a second light-receiving unit 22. The substrate 40 may be transparent to the light 14. When detecting breath, the substrate 40 is, for example, a GaAs substrate.

[0070] The substrate 40 has a first main surface 41 and a second main surface 42. The first main surface 41 and the second main surface 42 are two main surfaces that constitute the substrate 40. In this example, of the two main surfaces, the first main surface 41 is the main surface on the positive side in the Z-axis direction, and the second main surface 42 is the main surface on the negative side in the Z-axis direction. The first main surface 41 faces the path 12 through which the exhaled air passes.

[0071] The light-emitting element 44 and the second light-receiving portion 22 may be provided on the same substrate. In this example, the light-emitting element 44 and the second light-receiving portion 22 are provided on the second main surface 42 of the substrate 40. The light-emitting element 44 has a laminated structure of a PN junction or a PIN junction. By supplying power to this laminated structure, the light-emitting element 44 operates as an LED and emits light 14 with a wavelength according to the band gap of the material of the laminated structure. When detecting exhaled breath, the light-emitting element 44 may use InAlSb as the laminated structure, which can output light in the vicinity of the absorption wavelength of carbon dioxide. The light-emitting element 44 described above is called a quantum infrared light-emitting element.

[0072] A portion of the light 14 travels through the substrate 40, passes through the first main surface 41, and is emitted to the path 12. Meanwhile, another portion of the light 14 travels through the substrate 40, is reflected by the first main surface 41, and is incident on the second light receiving section 22.

[0073] The second light receiving unit 22 receives the light 14 that has traveled through the substrate 40. The second light receiving unit 22 receives the light 14 that has not passed through the path 12 through which the exhaled air passes. This makes it possible to correct output fluctuations due to changes in the light amount of the light emitting element 44 and temperature.

[0074] The second light receiving section 22 may also have a laminated structure. The laminated structure of the second light receiving section 22 may be a PN junction or PIN junction diode structure. The laminated structure and material of the second light receiving section 22 may be similar to the laminated structure and material of the light emitting element 44. This allows the temperature characteristics of the second light receiving section 22 and the temperature characteristics of the light emitting element 44 to be aligned. The above-mentioned second light receiving section 22 is referred to as a quantum infrared light receiving element.

[0075] Fig. 9B is a diagram showing an example of a gas sensor 11 according to an embodiment of the present invention. Although an embodiment of the breath sensor 10 has been described in Fig. 1 to Fig. 9A, the above embodiment is not limited to a sensor that detects breath. The above embodiment can also be widely applied to a gas sensor 11 that detects a target gas.

[0076] The gas sensor 11 may have the configuration shown in Fig. 8 or Fig. 9A. The breath sensor 10 described in Fig. 2 to Fig. 9A may function as the gas sensor 11. For example, the gas sensor 11 may include a light emitting unit 16, a first light receiving unit 18, and a calculation unit 20. The calculation unit 20 of the gas sensor 11 may perform the signal processing described in Fig. 2, may perform the baseline calculation and removal described in Fig. 3 to Fig. 5B, may perform the signal processing described in Fig. 6A to Fig. 7B, or may perform a combination of these.

[0077] The calculation unit 20 of the gas sensor 11 may calculate a baseline of the waveform of the first light-receiving signal from the light-receiving signal ratio based on a frequency component of the light-receiving signal ratio lower than the set first cutoff frequency, and remove the baseline from the light-receiving signal ratio. In calculating the baseline, the calculation unit 20 of the gas sensor 11 may change the first cutoff frequency in response to a change in the signal value of the light-receiving signal ratio.

[0078] By applying the above embodiment, it is possible to eliminate the influence of disturbances other than the detection target, particularly in cases where the output value of the gas sensor 11 is prone to change over time and the direction of the output fluctuation when detecting the detection target is fixed. As an example, this is effective for a methane gas sensor installed in an outdoor location where the environmental temperature is prone to change.

[0079] Fig. 10 is a flowchart showing an example of a breath detection method according to an embodiment of the present invention. The breath detection method according to an embodiment of the present invention will be described using the breath sensor 10 of Fig. 1 as an example. The breath detection method includes a light emission step S100, a first light receiving step S104, a first output step S108, and a calculation step S112. The calculation step S112 includes a calculation step S114 and a detection step S116.

[0080] The light emitting step S100 is a step in which the light emitting unit 16 irradiates light 14 toward the pathway 12 through which the exhaled air passes. The first light receiving step S104 is a step in which the first light receiving unit 18 receives at least a part of the light 14 irradiated in the light emitting step S100. The first output step S108 is a step in which the first light receiving unit 18 outputs a first light receiving signal according to the light receiving result in the first light receiving step S104. The calculation step S112 is a step in which the calculation unit 20 performs a calculation on the first light receiving signal output in the first output step S108.

[0081] The calculation step S114 is a step in which the calculation unit 20 calculates a baseline of the waveform of the first received light signal based on a frequency component of the first received light signal that is lower than the set first cutoff frequency. The detection step S116 is a step in which the calculation unit 20 detects exhalation based on a signal obtained by removing the baseline calculated in the calculation step S114 from the first received light signal.

[0082] The calculation step S112 may be a step in which the calculation section 20 calculates at least one of the period and length of breathing. The first cutoff frequency may be set in accordance with a change in the signal value of the first received light signal.

[0083] The calculation step S112 may be a step in which the calculation unit 20 sets the first cutoff frequency when the signal value of the first received light signal, for which the baseline value is to be calculated, has increased from a past signal value in the time waveform of the first received light signal, higher than the first cutoff frequency when the signal value has decreased from the past signal value. The calculation step S112 may be a step in which the calculation unit 20 sets the first cutoff frequency when the signal value of the first received light signal, for which the baseline value is to be calculated, has increased by 20% or more from a past signal value in the time waveform of the first received light signal, higher than the first cutoff frequency when the signal value has decreased by 20% or more from the past signal value.

[0084] The calculation step S112 may be a step in which the calculation unit 20 sets the first cutoff frequency when the signal value of the first received light signal, for which the baseline value is to be calculated, has increased relative to the signal value at the immediately preceding timing in the time waveform of the first received light signal, to be 10 times or more higher than the first cutoff frequency when the signal value has decreased relative to the immediately preceding signal value. The calculation step S112 may be a step in which the calculation unit 20 sets the first cutoff frequency when the signal value of the first received light signal, for which the baseline value is to be calculated, has increased by 20% or more relative to the signal value at the immediately preceding timing in the time waveform of the first received light signal, to be 10 times or more higher than the first cutoff frequency when the signal value has decreased by 20% or more relative to the immediately preceding signal value.

[0085] Fig. 11 is a flowchart showing another example of a breath detection method according to an embodiment of the present invention. The breath detection method of Fig. 11 differs from the breath detection method of Fig. 10 in that it further includes a second light receiving step S120, a second output step S124, and a correction step S128. The calculation step S112 may include the correction step S128.

[0086] The second light receiving step S120 is a step in which the second light receiving unit 22 receives the light 14 that has not passed through the path 12 through which the exhaled air passes, among the light 14 irradiated by the light emitting unit 16. The second output step S124 is a step in which the second light receiving unit 22 outputs a second light receiving signal according to the light receiving result in the second light receiving step S120. The correction step S128 is a step in which the calculation unit 20 corrects the first light receiving signal based on the signal value of the second light receiving signal. In this example, the calculation step S114 is a step in which the calculation unit 20 calculates a baseline of the waveform of the first light receiving signal based on the frequency component of the first light receiving signal that is lower than the set first cutoff frequency and has been corrected in the correction step S128.

[0087] 12 is a schematic diagram showing an example of a breath detection system 100 according to an embodiment of the present invention. The breath detection system 100 detects the breath of a user 200. The breath detection system 100 may be a part or an entirety of a device worn by the user 200. The breath detection system 100 of this example is an entirety of a headset worn on the head of the user 200.

[0088] The breath detection system 100 shown in Fig. 12 includes a main body 102 and a breath sensor 10. The breath sensor 10 is provided in the main body 102 and detects the breath of a user 200. The breath is the breath exhaled by the user 200 when breathing. The breath sensor 10 may detect the breath of the user 200 based on the concentration of carbon dioxide. The breath sensor 10 may measure the concentration of carbon dioxide in the measurement space by measuring the absorption intensity of infrared light that has passed through the measurement space.

[0089] The breath sensor 10 may determine that the breath of the user 200 has been detected when the measured carbon dioxide concentration is equal to or higher than a reference value. The breath sensor 10 may detect the breathing cycle or length of breathing of the user 200 based on the breath detection result. The breath sensor 10 may calculate the period during which the carbon dioxide concentration is equal to or higher than the reference value as the length of one breath. The breath sensor 10 may calculate the length obtained by dividing a unit time by the number of breaths within the unit time as the breathing cycle.

[0090] The main body unit 102 of this example has a fixed part 110 and a movable part 120. As an example, the fixed part 110 is attached to the head of the user 200. The fixed part 110 may have a sound generating part 112 that generates sound. The sound generating part 112 may include a pad part that contacts the ears of the user 200 when the main body unit 102 is attached, and a speaker provided on the pad part. The fixed part 110 may include two sound generating parts 112 corresponding to both ears of the user 200, and an arm part 113 that connects the two sound generating parts 112.

[0091] The movable part 120 is provided so as to be movable with respect to the fixed part 110. In other words, the position of at least a part of the movable part 120 relative to at least a part of the fixed part 110 is changeable. The movable part 120 in this example has a rod-shaped part extending from the fixed part 110. The rod-shaped part is connected to a connection part 111 in the fixed part 110. The rod-shaped part is rotatable with respect to the fixed part 110, with the connection part 111 as the rotation axis.

[0092] The breath sensor 10 may be provided on the movable part 120. The breath sensor 10 may be capable of changing its position relative to the fixed part 110 in accordance with the movement of the movable part 120. The breath sensor 10 in this example is provided on the end of the movable part 120 opposite to the connection part 111. A sound detection unit 122 that detects sound is provided on the end. The sound detection unit 122 is, for example, a microphone. The breath sensor 10 may be provided on the sound detection unit 122. By arranging the sound detection unit 122 and the breath sensor 10 in close proximity, the breath sensor 10 is more likely to be arranged in the vicinity of the mouth of the user 200, making it easier to detect the breath of the user 200.

[0093] The main body 102 may further include a display unit that displays information. The display unit may be, for example, a head-mounted display connected to the fixed unit 110. The display unit may be provided movably with respect to the fixed unit 110. The breath sensor 10 may be provided on the display unit.

[0094] FIG. 13 is a functional block diagram showing an example of a breath detection system 100. The breath detection system 100 of this example includes a main body unit 102, a state detection unit 150, and a control unit 140. The main body unit 102 is similar to the example described in FIG. 12. The main body unit 102 of this example has a fixed unit 110 and a movable unit 120. The breath sensor 10 is provided in the movable unit 120. The calculation unit 20 (see FIG. 1) may function as the control unit 140. The calculation unit 20 may function as a part of the state detection unit 150.

[0095] 13, the status detection unit 150 and the control unit 140 are disposed outside the main body unit 102, but the status detection unit 150 and the control unit 140 may be provided in the main body unit 102. The control unit 140 may be provided on the same board as the breath sensor 10. The control unit 140 may receive a signal from the status detection unit 150. The control unit 140 may receive the signal by a wired or wireless signal transmission means.

[0096] The state detection unit 150 detects the state of at least one of the main body unit 102 and the breath sensor 10. In this specification, the state of at least one of the main body unit 102 and the breath sensor 10 may be simply referred to as the state of the main body unit 102. The state of the main body unit 102 may include at least one of a position state indicating the relative position of a component such as the movable unit 120 with respect to the fixed unit 110, an operation state indicating the electrical state of the main body unit 102, and an environmental state indicating the surrounding environment of the main body unit 102.

[0097] The position state may be information indicating the state of a part that affects the relative position of the breath sensor 10 with respect to the fixed part 110. The position state may be information that directly indicates the relative position of the breath sensor 10.

[0098] The operating state may be information indicating the presence, magnitude, frequency, etc. of power supply power or a control signal input to the main body unit 102. The operating state may be information indicating the presence, magnitude, frequency, etc. of an electric signal generated by each component of the main body unit 102. The operating state may be information indicating the amount of power consumption consumed by the main body unit 102.

[0099] More specifically, the operating state may be information indicating whether or not a control signal for causing the sound generating unit 112 to generate a sound has been input to the main unit 102, or may be information indicating whether or not a control signal for causing the display unit to display information has been input to the main unit 102. The sound detecting unit 122 converts the detected sound into an electric signal. The operating state may be information indicating the presence, magnitude, frequency, etc. of the electric signal output by the sound detecting unit 122. When the power supply power of the main unit 102 is supplied by a storage battery of the main unit 102, the operating state may be information indicating the remaining capacity of the storage battery.

[0100] The environmental state may be information indicating at least one of the temperature, humidity, air pressure, and wind speed around the main body unit 102. The state detection unit 150 may include a sensor that detects these pieces of information.

[0101] The breath sensor 10 has a plurality of operation modes with different power consumption. The breath sensor 10 of this example has, as operation modes, an active state in which breath can be detected, and a standby state in which power consumption is lower than that of the active state. For example, in the active state, the light-emitting element of the breath sensor 10 continuously irradiates light such as infrared light. The power consumption per unit time of the light-emitting element in the standby state is smaller than the power consumption per unit time of the light-emitting element in the active state.

[0102] The light emitting element may have a longer light emitting period in the standby state than the light emitting period in the active state. The light emitting element may have a smaller light emitting intensity in the standby state than the light emitting element in the active state. In the standby state, the light emitting element may stop emitting light.

[0103] The control unit 140 transitions the operation mode of the breath sensor 10 based on the state of at least one of the main body unit 102 and the breath sensor 10 detected by the state detection unit 150. When the state of the main body unit 102 satisfies a preset condition, the control unit 140 may transition the operation mode so as to reduce the power consumption of the breath sensor 10 compared to when the condition is not satisfied. The condition is, for example, a condition indicating that the breath sensor 10 is in a state in which it should not detect breath.

[0104] For example, when the breath sensor 10 is placed far from the mouth of the user 200, the breath sensor 10 cannot accurately detect the breath of the user 200. When the position state of the main body 102 satisfies a preset condition, the control unit 140 may transition the operation mode to reduce the power consumption of the breath sensor 10. This allows the power consumption of the breath sensor 10 to be reduced.

[0105] In a state where the application software operating the main body unit 102 does not request breath detection of the user 200, the breath sensor 10 does not need to detect breath. When the operating state indicated by a control signal or the like to the main body unit 102 satisfies a preset condition, the control unit 140 may transition the operation mode to reduce the power consumption of the breath sensor 10. This allows the power consumption of the breath sensor 10 to be reduced. In addition, when the remaining capacity of the storage battery of the main body unit 102 falls below a preset reference value, the control unit 140 may transition the operation mode to reduce the power consumption of the breath sensor 10. This allows the consumption of the remaining capacity of the storage battery to be suppressed.

[0106] When the user 200 is speaking, the breath sensor 10 cannot accurately detect information related to the breath of the user 200 (such as breathing cycle). When the amplitude of the electrical signal output by the sound detection unit 122 satisfies a preset condition, the control unit 140 may transition the operation mode to reduce the power consumption of the breath sensor 10. This allows the power consumption of the breath sensor 10 to be reduced.

[0107] Depending on the temperature, humidity, air pressure, or wind speed around the breath sensor 10, the breath sensor 10 may not be able to detect breath with high accuracy. For example, the temperature characteristics of the breath sensor 10 may cause errors in the detection results of the breath sensor 10. In addition, if condensation occurs on the optical elements such as the light-emitting element and the light-receiving element of the breath sensor 10, errors may occur in the detection results of the breath sensor 10. In addition, if the wind speed is too strong, the breath is likely to diffuse into the space while being transmitted from the mouth of the user 200 to the breath sensor 10, and errors may occur in the detection results of the breath sensor 10. When the environmental state of the main body 102 satisfies a preset condition, the control unit 140 may transition the operation mode to reduce the power consumption of the breath sensor 10. This allows the power consumption of the breath sensor 10 to be reduced.

[0108] Fig. 14 is a diagram showing an example of the position state of the main body part 102. Compared to the example shown in Fig. 12, the rotation angle of the movable part 120 in this example relative to the fixed part 110 is changed. As a result, the breath sensor 10 in this example is disposed farther from the mouth of the user 200 than the example shown in Fig. 12. In such a case, the breath sensor 10 cannot accurately detect the breath of the user 200.

[0109] The control unit 140 may control the operation mode of the breath sensor 10 depending on whether or not the state of the movable unit 120 satisfies a preset condition. The control unit 140 may transition the breath sensor 10 to a standby state when the rotation angle of the movable unit 120 falls outside a preset range.

[0110] 15 is a diagram showing another example of the state of the main body 102. In this example, the user 200 is speaking. The breath detected by the breath sensor 10 when the user 200 is speaking may differ from the breath detected when the user 200 is not speaking. For this reason, when attempting to detect the length and cycle of breathing when the user 200 is not speaking, even if the breath sensor 10 is operated when the user 200 is speaking, the length and cycle of breathing cannot be detected with high accuracy.

[0111] The control unit 140 may control the operation mode of the breath sensor 10 depending on whether or not the electrical signal output by the sound detection unit 122 satisfies a preset condition. When the magnitude of the amplitude of the electrical signal (corresponding to the volume of the user 200's voice) becomes equal to or greater than a reference value, the control unit 140 may transition the breath sensor 10 to a standby state.

[0112] 16 is a diagram showing a configuration example of the state detection unit 150. The main body unit 102 of this example has a storage battery 117 that supplies power to the main body unit 102. The state detection unit 150 of this example has at least one or all of a position state detection unit 151, an environmental state detection unit 152, and an operation state detection unit 153.

[0113] The position state detection unit 151 detects the above-mentioned position state. The position state detection unit 151 may have a sensor that detects the position state of the movable unit 120, such as the rotation angle.

[0114] The environmental condition detection unit 152 detects the above-mentioned environmental conditions. The environmental condition detection unit 152 may have at least one of a temperature sensor, a humidity sensor, a pressure sensor, and a wind speed sensor.

[0115] The operation state detection unit 153 detects the operation state described above. The sound detection unit 122 and the sound generation unit 112 shown in FIG. 12 and the like may be included in the operation state detection unit 153. The operation state detection unit 153 in this example has at least one or all of the sound detection unit 122, the sound generation unit 112, the mounting detection unit 154, the signal detection unit 155, the remaining capacity detection unit 156, and the power consumption detection unit 157.

[0116] The sound detection unit 122 detects sound. The control unit 140 may control the operation mode of the breath sensor 10 based on the state of the sound detected by the sound detection unit 122. When the loudness of the sound detected by the sound detection unit 122 is equal to or greater than a set reference value, the control unit 140 may transition the breath sensor 10 to a standby state. When the loudness of the sound detected by the sound detection unit 122 is smaller than a set reference value, the control unit 140 may transition the breath sensor 10 to an active state.

[0117] The control unit 140 may transition the breath sensor 10 to a standby state when the sound detected by the sound detection unit 122 is the voice of the user 200. The control unit 140 may transition the breath sensor 10 to an active state when the voice of the user 200 is no longer detected. The control unit 140 may determine whether or not the voice of the user 200 has been detected based on the magnitude of a preset frequency component of the electrical signal output by the sound detection unit 122. The frequency component is, for example, a component not less than 80 Hz and not more than 1 kHz.

[0118] The sound generating unit 112 generates a sound. The control unit 140 may control the operation mode of the breath sensor 10 based on the state of the sound generated or about to be generated by the sound generating unit 112. For example, when it is desired to detect the breath of the user 200 who is listening to a sound such as music, the breath sensor 10 may be transitioned from the standby state to the active state when the sound generating unit 112 generates or is about to generate a sound such as music. In another example, when it is desired to detect the breath of the user 200 who is quiet, the breath sensor 10 may be transitioned from the standby state to the active state when the volume of the sound generated or about to be generated by the sound generating unit 112 is equal to or less than a reference value.

[0119] The wearing detection unit 154 determines whether the main body unit 102 is worn by the user 200. The wearing detection unit 154 may be a distance detection unit that detects the distance between the main body unit 102 and another object (e.g., the user 200). The wearing detection unit 154 may determine that the main body unit 102 is worn when the distance is equal to or less than a reference value, and may determine that the main body unit 102 is not worn when the distance is greater than the reference value. The control unit 140 may transition the breath sensor 10 to a standby state when the main body unit 102 is not worn. The control unit 140 may transition the breath sensor 10 to an active state when the main body unit 102 is worn.

[0120] The signal detection unit 155 detects the state of an input signal input to the main body unit 102 or an output signal generated by the main body unit 102. The input signal may be a signal that specifies the state of the breath sensor 10. The control unit 140 may transition the breath sensor 10 to an active state or a standby state based on the input signal. The input signal may be a signal that controls the sound generation unit 112 or the display unit.

[0121] The state of the main body 102 may be changed by a control signal from application software running on a computer inside or outside the main body 102. The control signal may control the sound generating unit 112 or the display unit. The signal detecting unit 155 may control the operation mode of the breath sensor 10 based on the control signal.

[0122] The control unit 140 may transition the breath sensor 10 to an active state or a standby state when a control signal for setting the sound generating unit 112 or the display unit to a predetermined state is input. The predetermined state may be set in advance in the control unit 140. The control unit 140 may transition the breath sensor 10 to an active state when the maximum volume generated by the sound generating unit 112 or the maximum luminance of an image displayed by the display unit is greater than a predetermined reference value. In another example, the control unit 140 may transition the breath sensor 10 to a standby state when the maximum volume generated by the sound generating unit 112 or the maximum luminance of an image displayed by the display unit is greater than a predetermined reference value. The state to which the breath sensor 10 is transitioned depending on the comparison result between the state value and the reference value may be specified by application software.

[0123] The control unit 140 may control the operation mode of the breath sensor 10 based on the type of the application software described above. The control signal may include information indicating the type of the application software. For example, when the application software is a game application, the control unit 140 controls the breath sensor 10 to an active state. When the application software is a conference application for holding a conference between users on the web, the control unit 140 may control the breath sensor 10 to a standby state.

[0124] The remaining capacity detection unit 156 may detect the remaining capacity of the power that the storage battery 117 can output, may detect the charging state of the storage battery 117 (for example, whether charging has started, whether charging has stopped, or whether charging is in progress), or may detect both the remaining capacity and the charging state. The control unit 140 may control the breath sensor 10 based on the remaining capacity of the storage battery 117, or may control the breath sensor 10 based on the charging state of the storage battery 117. When the remaining capacity falls below a reference value, the control unit 140 may transition the breath sensor 10 to a standby state. When the control unit 140 detects that charging of the storage battery 117 has started, the control unit 140 may transition the breath sensor 10 to an active state. When the control unit 140 detects that charging of the storage battery 117 has started, the control unit 140 may transition the breath sensor 10 to a standby state for rapid charging of the storage battery 117.

[0125] The power consumption detection unit 157 detects the power consumption of the main body unit 102. The main body unit 102 may have a plurality of operating states with different power consumption. For example, the main body unit 102 has an activated state in which power is supplied from the power source and a stopped state in which power is not supplied from the power source. The control unit 140 may control the operating mode of the breath sensor 10 based on the operating state of the main body unit 102. When the main body unit 102 is in the activated state, the control unit 140 may set the breath sensor 10 to an active state, and when the main body unit 102 is in the stopped state, the control unit 140 may set the breath sensor 10 to a standby state. When the power consumption of the main body unit 102 is equal to or less than a set reference value, the control unit 140 may transition the breath sensor 10 to the standby state.

[0126] The operation state detection unit 153 may detect the operation state of the main body unit 102 based on the breath detected by the breath sensor 10. In other words, the breath sensor 10 may function as the operation state detection unit 153. The control unit 140 may control the operation mode of the breath sensor 10 based on the breath detected by the breath sensor 10. The control unit 140 may transition the breath sensor 10 to a standby state when the period during which the volume of the breath is equal to or less than a set value continues for a set period or more. In another example, when it is desired to detect breath when the user 200 is excited, the control unit 140 may transition the breath sensor 10 to a standby state when the breathing period calculated from the breath falls within a set steady range.

[0127] 16, it is possible to reduce the power consumption of the breath sensor 10. In particular, when power is not supplied to the body part 102 from an external power source, it is preferable to reduce the power consumption of the breath sensor 10 so that the driving time of the body part 102 by the storage battery 117 is not shortened.

[0128] The control unit 140 may evaluate each state of the main body unit 102 described in FIG. 16 and the like as a state value. The state value is a numerical value indicating the degree of the state. For example, the position state of the movable part 120 can be evaluated by the relative coordinate value of the evaluation position, such as the tip of the movable part 120, with respect to a reference position, such as the connection part 111 of the fixed part 110, or the rotation angle of the movable part 120 with respect to the fixed part 110. The state value may be a value of temperature, humidity, pressure, or wind speed, may be a loudness, frequency, or duration of detection of a sound detected by the sound detection unit 122, may be a loudness, frequency, or duration of generation of a sound generated by the sound generation unit 112, may be a remaining capacity of the storage battery 117, may be a power consumption of the main body unit 102, or may be a value of another parameter.

[0129] The control unit 140 may control the operation mode of the breath sensor 10 by comparing the state value of the main body unit 102 with a set reference value. The reference value may be set for each type of state of the main body unit 102. The type of state is the type of parameter such as angle, sound volume, etc., that indicates the state of the main body unit 102.

[0130] The reference value when the breath sensor 10 transitions from the active state to the standby state may be the same as or different from the reference value when the breath sensor 10 transitions from the standby state to the active state. By making the reference values ​​different, it is possible to prevent the state of the breath sensor 10 from transitioning continuously in a short cycle.

[0131] The main body unit 102 may have a plurality of types of states, and each type of state may be changeable. For example, the main body unit 102 has a plurality of types of states, such as the position of the movable unit 120, the volume of the sound detected by the sound detection unit 122, etc. Each state, such as the position of the movable unit 120, the volume of the sound detected by the sound detection unit 122, etc., is changeable.

[0132] The control unit 140 may control the operation mode of the breath sensor 10 based on two or more types of states of the main body unit 102. When at least one of the multiple states to be used for controlling the operation mode of the breath sensor 10 indicates that the breath sensor 10 should be in a standby state, the control unit 140 may control the breath sensor 10 to a standby state. In other words, when all of the multiple states to be used for controlling the operation mode of the breath sensor 10 indicate that the breath sensor 10 should be in an active state, the control unit 140 may control the breath sensor 10 to an active state.

[0133] In another example, the multiple types of states of the main body unit 102 may be categorized into two or more types. For one or more states included in a first category, if at least one state indicates that the breath sensor 10 should be in a standby state, the breath sensor 10 may be controlled to a standby state. For multiple states included in a second category, if two or more states indicate that the breath sensor 10 should be in a standby state, the breath sensor 10 may be controlled to a standby state.

[0134] The first category may include a state for determining that breath detection is unnecessary or that power consumption due to breath detection is unacceptable. For example, the first category includes a state in which the main body unit 102 is attached, a state of power consumption of the main body unit 102, a state of remaining capacity of the storage battery 117, and a state of the type of application software.

[0135] The second category may include conditions for determining that the accuracy of breath detection is reduced. For example, the second category includes the condition of the environment surrounding the breath sensor 10, the positional condition of the movable part 120, the sound condition of the sound detection part 122, and the sound condition of the sound generation part 112.

[0136] The control unit 140 may perform processing using a second type of state in the determination using the first type of state of the main body unit 102. For example, the control unit 140 may compare the time waveform of the sound detected by the sound detection unit 122 with the time waveform of the breath (e.g., carbon dioxide concentration) detected by the breath sensor 10 to determine whether or not the sound detected by the sound detection unit 122 is a voice from the user 200. Before this determination, the breath sensor 10 is in an active state. When the control unit 140 determines that a voice from the user 200 has been detected, it may transition the breath sensor 10 from the active state to the standby state.

[0137] The control unit 140 may determine that a voice from the user 200 has been detected when the correlation coefficient between the time waveform of the sound and the time waveform of the exhaled breath is equal to or greater than a reference value. The correlation coefficient is expressed as a real number ranging from 1 to -1. When the correlation coefficient is 1, the two time waveforms match, and the correlation coefficient approaches 0 as the similarity between the two time waveforms decreases. When the user 200 is speaking, carbon dioxide is discharged in response to the speaking. Therefore, when the user 200 is speaking, the time waveform of the sound and the time waveform of the exhaled breath often change in sync. Therefore, the correlation coefficient becomes large.

[0138] The control unit 140 may determine that the voice of the user 200 has been detected when the volume (e.g., peak value) of the sound detected by the sound detection unit 122 is equal to or greater than a reference value and the correlation coefficient between the time waveform of the sound and the time waveform of the exhaled breath is equal to or greater than a reference value. By such control, the voice of the user 200 can be detected with higher accuracy.

[0139] The control unit 140 can perform processing that assigns priorities to categories of the state of the main body unit 102. The priority of each category may be set in advance by the user, the manufacturer, or the like. Each category includes one or more types of states of the main body unit 102. Each state of the main body unit 102 indicates whether the breath sensor 10 should be in an active state or a standby state.

[0140] As an example, a first state of the main body unit 102 may indicate that the breath sensor 10 should be in an active state, and a second state of the main body unit 102 may indicate that the breath sensor 10 should be in a standby state. In this way, when multiple states of the main body unit 102 indicate that the breath sensor 10 should be controlled to different operation modes, the control unit 140 may determine to which category each state of the main body unit 102 belongs. The control unit 140 may control the operation mode of the breath sensor 10 based on the state of the main body unit 102 that belongs to the category with the highest priority.

[0141] As an example, an example in which the state of the main body unit 102 is divided into three categories will be described. In this example, the priority of the first category is higher than the priority of the third category. The priority of the second category may be lower than the priority of the first category, or may be the same. For example, the first category includes the state of application software. The state of application software may be the contents of instructions from the application software. For example, the second category includes a state for determining that power consumption due to breath detection is not acceptable, the wearing state of the main body unit 102, the state of power consumption of the main body unit 102, the state of remaining capacity of the storage battery 117, and the like. For example, the third category includes a state for determining that the accuracy of breath detection is reduced.

[0142] As a more specific example, a case will be described in which the application software requests the breath sensor 10 to be in an active state in order to adjust the position of the breath sensor 10. For example, the position of the breath sensor 10 may be adjusted in order to accurately detect the breath of the user 200. In this case, the state of the application software belonging to the first category requests the active state. On the other hand, the states of the main body unit 102 belonging to the second and third categories are various. For example, when the position of the breath sensor 10 is in a position where the breath cannot be accurately detected, the state of the main body unit 102 included in the third category requests the breath sensor 10 to be in a standby state. In such a case, the control unit 140 may prioritize the request from the application software belonging to the first category and may put the breath sensor 10 in an active state. Also, even if the state of the main body unit 102 belonging to the third category requests the breath sensor 10 to be in a standby state in order to request a review of the surrounding environment, the control unit 140 may prioritize the first category and maintain the breath sensor 10 in an active state. For example, when the wind from an electric fan hits the sound detection unit 122 and generates a sound, the state of the main body unit 102 belonging to the third category requires the breath sensor 10 to be in a standby state. In such a case, by maintaining the breath sensor 10 in an active state in response to a request from the application software, it is possible to urge the user not to be hit by the wind from the electric fan.

[0143] As another example, the control unit 140 can perform prioritized processing by combining multiple categories. As an example, at least one of the multiple categories may be an auxiliary category. When the states of the main body unit 102 belonging to two or more categories indicate that the breath sensor 10 should be controlled to different states, the control unit 140 may control the operation mode of the breath sensor 10 based on the state of the main body unit 102 belonging to the auxiliary category.

[0144] As a more specific example, the first category includes the state of the application software. The second category includes a state for determining that power consumption due to breath detection is not acceptable, the wearing state of the main body unit 102, the state of power consumption of the main body unit 102, and the state of the remaining capacity of the storage battery 117. The third category includes a charging state indicating whether the storage battery 117 is charging or not. The fourth category includes a state for determining that the accuracy of breath detection is reduced. In this example, the third category is an auxiliary category. Here, it is assumed that the first category requests an active state, and the second and fourth categories request standby. When the requests from the other multiple categories are different from each other, the control unit 140 may transition the breath sensor 10 to an active state or to a standby state based on the charging state in the third category.

[0145] The control unit 140 may control the state of the breath sensor 10 based on different types of states of the main body unit 102 when transitioning the breath sensor 10 from an active state to a standby state and when transitioning the breath sensor 10 from a standby state to an active state. The control unit 140 may transition the breath sensor 10 from a standby state to an active state based on the position state of the movable unit 120. For example, the control unit 140 transitions the breath sensor 10 to an active state when the breath sensor 10 is placed near the mouth of the user 200 due to the position state of the movable unit 120. The control unit 140 may transition the breath sensor 10 from an active state to a standby state based on the state of the sound detected by the sound detection unit 122. For example, the control unit 140 transitions the breath sensor 10 from an active state to a standby state when the sound detection unit 122 detects the user 200's speech.

[0146] When there are three or more power consumption states of the breath sensor 10, the control unit 140 may control the transition of the breath sensor 10 to each operation mode based on different types of states of the main body unit 102. As an example, the breath sensor 10 has three operation modes: a maximum performance state, an eco-driving state, and a standby state. The maximum performance state is an operation mode that consumes the most power among the three operation modes and has the highest accuracy or frequency of breath detection. The eco-driving state is an operation mode that consumes less power and has at least one of the accuracy and frequency of breath detection lower than the maximum performance state. The standby state is an operation mode that consumes the least power among the three operation modes and has the lowest accuracy or frequency of breath detection. The breath sensor 10 in the standby state does not need to perform breath detection.

[0147] For example, the control unit 140 may transition the breath sensor 10 to an arbitrary operation mode based on a request from the application software. When the breath sensor 10 is in the maximum performance state and the remaining capacity of the storage battery 117 decreases, the control unit 140 may transition the breath sensor 10 to an eco-driving state. When the remaining capacity of the storage battery 117 further decreases, the control unit 140 may transition the breath sensor 10 to a standby state. In addition, when charging of the storage battery 117 is started according to the charging state, the control unit 140 may transition the breath sensor 10 from the standby state to the maximum performance state. When charging of the storage battery 117 is interrupted and terminated but the remaining battery capacity of the storage battery 117 is not acceptable, the control unit 140 may transition the breath sensor 10 from the maximum performance state to the standby state.

[0148] The control unit 140 may adjust the criteria for determining the state of the main body unit 102 when controlling the current operation mode of the breath sensor 10, based on the state of the main body unit 102 used for determination when the operation mode of the breath sensor 10 was previously controlled. The control unit 140 may change the criteria for determining whether the breath sensor 10 transitions to the standby state between immediately after the movable unit 120 is operated to move the sound detection unit 122 near the mouth of the user 200 and in other cases.

[0149] Immediately after the sound detection unit 122 is moved to the vicinity of the mouth of the user 200, there is a relatively high possibility that the user 200 will speak. If the breath sensor 10 transitioned to the active state in response to the position state of the movable part 120 in the previous control, the control unit 140 may set a reference value for comparison with the volume of the sound detected by the sound detection unit 122 lower than the normal value. If the volume of the sound detected by the sound detection unit 122 is larger than the reference value, the control unit 140 determines that the user 200 is speaking. This makes it easier to detect the user 200's speech. If the control unit 140 detects the user 200's speech, it transitions the breath sensor 10 to the standby state. The normal state refers to a situation in which the breath sensor 10 transitioned to the active state in response to a state other than the position state of the movable part 120 in the previous control.

[0150] If the breath sensor 10 transitioned to the active state in response to the position state of the movable part 120 in the previous control, the control part 140 may set a reference value to be compared with the remaining capacity of the storage battery 117 higher than normal. If the remaining capacity of the storage battery 117 is lower than the reference value, the control part 140 transitions the breath sensor 10 to the standby state. In this way, during a period when the user 200 is likely to speak, breath can be detected only when the remaining capacity of the storage battery 117 has a margin.

[0151] 17 is a diagram showing an example of a display device 300 according to an embodiment of the present invention. The display device 300 includes an HMD (head-mounted) type display unit 210 and a CO2 (carbon dioxide) sensor 220. The display device 300 including the HMD type display unit 210 is, for example, VR (Virtual Reality) goggles, smart glasses, etc.

[0152] The display device 300 may include a plurality of CO2 (carbon dioxide) sensors 220. In this example, the display device 300 includes two CO2 (carbon dioxide) sensors 220 (CO2 (carbon dioxide) sensor 220-1 and CO2 (carbon dioxide) sensor 220-2). The display device 300 may include an exhaled air volume sensor 224.

[0153] The CO2 (carbon dioxide) sensor 220 and the breath volume sensor 224 may be provided in the housing 212 of the HMD (head-mounted) display unit 210. The display device 300 of this example has a plurality of openings 222 (openings 222-1 and 222-2) on the bottom surface 214 of the housing 212. In this example, the CO2 (carbon dioxide) sensor 220-1 is provided inside the housing 212, and the CO2 (carbon dioxide) sensor 220-2 is provided on the bottom surface 214. In this example, the CO2 (carbon dioxide) sensor 220-2 is exposed to the outside of the housing 212. The breath volume sensor 224 may be provided on the surface of the housing 212. In this example, the breath volume sensor 224 is provided on the bottom surface 214. When the display device 300 includes a voice acquisition unit that acquires the voice of the operator 310, the breath volume sensor 224 may be disposed in the voice acquisition unit or may be disposed in the vicinity of the voice acquisition unit.

[0154] The CO2 (carbon dioxide) sensor 220 acquires the CO2 (carbon dioxide) concentration in the breath of the operator 310 (described later). In this example, the CO2 (carbon dioxide) sensor 220-1 acquires the CO2 (carbon dioxide) concentration that has entered the inside of the housing 212 through the opening 222, and the CO2 (carbon dioxide) sensor 220-1 acquires the CO2 (carbon dioxide) concentration outside the housing 212. Data on the time change in the CO2 (carbon dioxide) concentration acquired by the CO2 (carbon dioxide) sensor 220 may be stored in a storage unit 270 (described later). Furthermore, the CO2 (carbon dioxide) sensor 220 may calculate the exhaled air volume Vb from the acquired data.

[0155] The breath volume sensor 224 acquires the breath volume Vb (described later) of the operator 310 (described later). In this example, the breath volume sensor 224 acquires the breath volume Vb that has entered the inside of the housing 212 through the opening 222. Data on the time change of the breath volume Vb (described later) acquired by the breath volume sensor 224 may be stored in a storage unit 270 (described later).

[0156] The CO2 (carbon dioxide) sensor 220 and the exhalation volume sensor 224 may acquire the exhalation cycle of the operator 310 (described later). The CO2 (carbon dioxide) sensor 220 and the exhalation volume sensor 224 may acquire an exhalation volume Vb (described later) per exhalation based on the exhalation cycle. For example, when the CO2 (carbon dioxide) sensor 220 detects a certain level of carbon dioxide concentration, the longer the breathing cycle, the larger the exhalation volume Vb is likely to be, and the shorter the breathing cycle, the smaller the exhalation volume Vb is likely to be.

[0157] Fig. 18 is a diagram showing an example of an operator 310 of the display unit 210. In Fig. 18, the CO2 (carbon dioxide) sensor 220 and the breath volume sensor 224 shown in Fig. 17 are omitted. In this example, the operator 310 wears the display device 300. The operator 310 is a living organism. In this example, the operator 310 is a human being. The operator 310 visually recognizes characters, images, etc. displayed on the display unit 210. The operator 310 may visually recognize images, etc. of a virtual reality space displayed on the display unit 210.

[0158] 19 is a block diagram showing an example of a display device 300 according to an embodiment of the present invention. The display device 300 may include a discrimination unit 230, an operation information acquisition unit 240, a recognition unit 250, a biometric information acquisition unit 260, a storage unit 270, a transmission unit 280, and a control unit 290.

[0159] The display device 300 or the breath detection system 100 (see FIG. 13) may be partly or entirely realized by a computer. The control unit 290 may be a CPU (Central Processing Unit) of the computer. When the display device 300 is realized by a computer, a display program for causing the computer to function as the display device 300 may be installed in the computer, and a display program for causing the computer to execute a display method described later may be installed in the computer.

[0160] The discrimination unit 230 discriminates the state of the operator 310 based on the CO2 (carbon dioxide) concentration acquired by the CO2 (carbon dioxide) sensor 220. The state of the operator 310 is defined as state S. The state S of the operator 310 may refer to the motion state of the operator 310, or may refer to the emotional state. The motion state of the operator 310 refers to, for example, whether the operator 310 is in a resting state or an exercising state. When the operator 310 is in an exercising state, the motion state of the operator 310 refers to, for example, whether the operator 310 is in an anaerobic exercise state or an aerobic exercise state. The emotional state of the operator 310 refers to, for example, whether the operator 310 is in an anxious state or a relieved state. Whether the operator 310 is in a resting state or an exercising state may be determined based on whether the CO2 (carbon dioxide) concentration in the exhaled breath is equal to or greater than a predetermined threshold Cth (described later), or may be determined based on whether the exhaled breath volume Vb (described later) is equal to or greater than a predetermined threshold Vth (described later).

[0161] The display unit 210 may display the state S of the operator 310 determined by the determination unit 230. The CO2 (carbon dioxide) concentration in the breath of the operator 310 tends to depend on the state S of the operator 310. For this reason, by the display unit 210 displaying the state S, the operator 310 can recognize his / her own state S.

[0162] The control unit 290 may control the display unit 210 based on the state S of the operator 310 determined by the determination unit 230. The control unit 290 controlling the display unit 210 based on the state S may include the control unit 290 controlling the display unit 210 to display text information related to the state S, and may also include controlling the brightness, color, and the like of the display unit 210 based on the state S. The text information related to the state S is, for example, text information such as "You are in an aerobic exercise state" which indicates that the operator 310 is in an aerobic exercise state.

[0163] The control unit 290 may control the display unit 210 based on the CO2 (carbon dioxide) concentration acquired by the CO2 (carbon dioxide) sensor 220 and a reference value of the CO2 (carbon dioxide) concentration. The reference value of the CO2 (carbon dioxide) concentration is set as a reference value Vs. The reference value Vs is a CO2 (carbon dioxide) concentration corresponding to the state S of the operator 310. As described above, the CO2 (carbon dioxide) concentration in the exhaled breath of the operator 310 is likely to depend on the state S of the operator 310.

[0164] The reference value Vs may be a CO2 (carbon dioxide) concentration in the exhaled breath of the operator 310, determined for each of a plurality of states S. The reference value Vs in one state S of the operator 310 may be different from the reference value Vs in another state S of the operator 310. The reference value Vs for each state S may be stored in the storage unit 270.

[0165] The reference value Vs may be determined for each of the multiple operators 310. The reference value Vs of one operator 310 in one state S (e.g., an anxious state) may be different from the reference value Vs of another operator 310 in the same state S (e.g., an anxious state). The reference value Vs for each operator 310 may be stored in the storage unit 270.

[0166] The control unit 290 may control the display unit 210 so that the CO2 (carbon dioxide) concentration acquired by the CO2 (carbon dioxide) sensor 220 approaches the reference value Vs. For example, when the state S of the operator 310 is determined to be an anaerobic exercise state, the control unit 290 controls the display unit 210 to display a phrase such as "Let's slow down the pace a little more" on the display unit 210 so that the CO2 (carbon dioxide) concentration in the breath of the operator 310 approaches the reference value Vs for aerobic exercise. For example, when the operator 310 is determined to be in an anxious state, the control unit 290 controls the display unit 210 to change the image displayed by the display unit 210 to a brighter color so that the CO2 (carbon dioxide) concentration in the breath of the operator 310 approaches the reference value Vs for a relaxed state.

[0167] The CO2 (carbon dioxide) sensor 220 may further acquire the CO2 (carbon dioxide) concentration in the breath of the operator 310 after the control unit 290 controls the display unit 210 based on the CO2 (carbon dioxide) concentration and the reference value Vs. The determination unit 230 may determine the state S of the operator 310 based on the CO2 (carbon dioxide) concentration after controlling the display unit 210. The display unit 210 may display the state S. This allows the operator 310 to check whether his or her own state S is the desired state S.

[0168] The control unit 290 may control the display unit 210 based on a change from a CO2 (carbon dioxide) concentration before controlling the display unit 210 to a CO2 (carbon dioxide) concentration after controlling the display unit 210. The determination unit 230 may determine a state S of the operator 310 after controlling the display unit 210. The control unit 290 may control the display unit 210 based on the state S of the operator 310. This allows the operator 310 to confirm whether the display unit 210 has been controlled so that his or her state S becomes the desired state S.

[0169] 20 is a diagram showing an example of a situation in which an operator 310 is using a device 400. The device 400 is a device that can affect an increase or decrease in the CO2 (carbon dioxide) concentration in the breath of the operator 310. The device 400 is, for example, an exercise device (exercise equipment), a controller for operating an experiential game device, and the like that is operated by the operator 310. In this example, the device 400 is a running machine.

[0170] The operator 310 may use the device 400 while wearing the display device 300. In FIG. 20, the CO2 (carbon dioxide) sensor 220 of the display device 300 is omitted. The CO2 (carbon dioxide) concentration in the breath of the operator 310 may change depending on the usage of the device 400 by the operator 310. When the device 400 is an exercise device, an experience-type game device, or the like, the state of the operator 310 is likely to change depending on the usage of the device 400. For example, when the device 400 is a running machine, the CO2 (carbon dioxide) concentration in the breath of the operator 310, or the exhalation volume Vb (described later) or the exhalation period is likely to change depending on the usage time of the operator 310. For example, when the device 400 is an experience-type game device, the operator 310 may become excited while playing the game. When the operator 310 becomes excited, the operator 310 may move his / her body. Therefore, depending on the usage conditions of the experience-based game device by the operator 310, the CO2 (carbon dioxide) concentration in the breath of the operator 310, or the breath volume Vb (described later) or breath cycle may change.

[0171] The device 400 may have a display unit 410, a transmission / reception unit 420, a control unit 430, an operation unit 440, and a recognition unit 450. The control unit 430 may be a CPU. The display unit 410 is, for example, a display, a monitor, etc. The operation unit 440 is, for example, a button, a keyboard, etc. The recognition unit 450 is, for example, an imaging device such as a camera. The operator 310 operates the device 400, such as setting the device 400, using the operation unit 440.

[0172] The control unit 290 may control the device 400 based on the state S of the operator 310 determined by the determination unit 230. The control unit 290 may generate a control signal Sc (see FIG. 19) for controlling the device 400. The transmission unit 280 (see FIG. 19) may transmit the generated control signal Sc to the transmission / reception unit 420 of the device 400. The transmission unit 280 may wirelessly transmit the control signal Sc to the transmission / reception unit 420. The transmission / reception unit 420 may receive the control signal Sc. The control unit 430 may control the display unit 410 based on the control signal Sc, and may control the device 400.

[0173] Control of the device 400 by the control unit 290 based on the state S may include the control unit 290 controlling the display unit 410 to display text information related to the state S, and may also include controlling the brightness, color, and the like of the display unit 410 based on the state S. The text information related to the state S is, for example, text information such as "You are in an aerobic exercise state" which indicates that the operator 310 is in an aerobic exercise state.

[0174] The control unit 290 may control the device 400 based on the CO2 (carbon dioxide) concentration in the breath of the operator 310 and a reference value Vs of the CO2 (carbon dioxide) concentration. The control unit 290 may control the device 400 so that the CO2 (carbon dioxide) concentration acquired by the CO2 (carbon dioxide) sensor 220 approaches the reference value Vs. For example, when the state S of the operator 310 is determined to be an anaerobic exercise state, the control unit 290 controls the display unit 410 to display a phrase such as "Slow down your pace a little more" on the display unit 410 so that the CO2 (carbon dioxide) concentration in the breath of the operator 310 approaches the reference value Vs for aerobic exercise. For example, when operator 310 is playing a game on an experiential game device, if state S of operator 310 is determined to be an anxious state, control unit 290 controls the screen of the game device so that state S of operator 310 approaches reference value Vs for a relaxed state, or controls the screen of the game device so that state S approaches reference value Vs for an excessively anxious state.

[0175] The CO2 (carbon dioxide) sensor 220 may further acquire the CO2 (carbon dioxide) concentration in the breath of the operator 310 after the control unit 290 controls the device 400 based on the CO2 (carbon dioxide) concentration and the reference value Vs. The discrimination unit 230 may discriminate the state S of the operator 310 based on the CO2 (carbon dioxide) concentration after controlling the device 400. The display unit 410 may display the state S. This allows the operator 310 to check whether his or her own state S is the desired state S.

[0176] The control unit 290 may control the device 400 based on a change from a CO2 (carbon dioxide) concentration before controlling the device 400 to a CO2 (carbon dioxide) concentration after controlling the device 400. The determination unit 230 may determine a state S of the operator 310 after controlling the device 400. The control unit 290 may control the device 400 based on the state S of the operator 310. This allows the operator 310 to confirm whether the device 400 has been controlled so that his or her state S becomes the desired state S.

[0177] The operation information acquisition unit 240 (see FIG. 19) acquires operation information of the device 400 by the operator 310. This operation information is referred to as operation information Ip. For example, in the case where the device 400 is an exercise machine that puts the operator 310 into an exercise state by operating the device 400, the operation information Ip is information on the operation state of the device 400 operated by the operator 310. The operation information Ip is, for example, information that the operation state of the exercise machine has been strengthened or weakened. Strengthening the operation state of the exercise machine refers, for example, to the operator 310 performing an operation to increase the power input to the exercise machine. Weakening the operation state of the exercise machine refers, for example, to the operator 310 performing an operation to decrease the power input to the exercise machine.

[0178] For example, when the device 400 is a running machine, if the operator 310 feels that the speed of the running surface of the running machine is high, the operator 310 may operate the device 400 by the operation unit 440 so as to decrease the speed of the running surface. In this case, the operation information Ip is information that the operator 310 has operated to decrease the speed of the running surface.

[0179] The discrimination unit 230 (see FIG. 19) may discriminate the state S of the operator 310 based on the CO2 (carbon dioxide) concentration in the breath of the operator 310 and the operation information Ip. The operation information Ip may reflect the state S of the operator 310. Therefore, the discrimination unit 230 may discriminate the state S of the operator 310 based on the operation information Ip. When the equipment 400 is a running machine, the discrimination unit 230 may discriminate the state S related to the exercise load of the operator 310 based on the operation information Ip.

[0180] The control unit 290 may control the device 400 based on the determined state S. For example, when the device 400 is a running machine and the state S of the operator 310 is determined to be an anaerobic exercise state, the control unit 290 controls the device 400 to increase the speed of the running surface of the running machine so that the CO2 (carbon dioxide) concentration in the breath of the operator 310 becomes the concentration in the case of aerobic exercise.

[0181] When the device 400 is an exercise machine, the display unit 210 may display a response to the operation of the device 400 by the operator 310 based on the state S of the operator 310 based on the CO2 (carbon dioxide) concentration determined by the determination unit 230 and the operation information Ip. For example, when the state S is determined to be an exercise state and the operation information Ip is information that the operating state of the exercise machine has been strengthened, the display unit 210 displays a message such as "You're doing well" to the operator 310 as a response to the operation of the device 400. For example, when the state S is determined to be an exercise state and the operation information Ip is information that the operating state of the exercise machine has been weakened, the display unit 210 displays a message such as "Thank you for your hard work" to the operator 310 as a response to the operation of the device 400. For example, when the state S is determined to be a resting state and the operation information Ip is information that the operating state of the exercise tool has been increased, the display unit 210 displays a message such as "Come on, let's do our best" to the operator 310 as a reaction to the operation on the device 400. For example, when the state S is determined to be a resting state and the operation information Ip is information that the operating state of the exercise tool has been decreased, the display unit 210 displays a message such as "Would you like to exercise?" to the operator 310 as a reaction to the operation on the device 400.

[0182] FIG. 21 is a diagram showing an example of a relationship between the CO2 (carbon dioxide) concentration in the exhaled breath of the operator 310 and the exhaled breath volume of the operator 310. The exhaled breath volume is defined as the exhaled breath volume Vb. The exhaled breath volume sensor 224 (see FIG. 17) acquires the exhaled breath volume Vb. The discrimination unit 230 may discriminate the state S of the operator 310 based on the CO2 (carbon dioxide) concentration and the exhaled breath volume Vb. The discrimination unit 230 may discriminate that the operator 310 is in an exercising state when the exhaled breath volume Vb is equal to or greater than a predetermined threshold value Vth. The discrimination unit 230 may discriminate that the operator 310 is in a resting state when the exhaled breath volume Vb is less than the threshold value Vth. The discrimination unit 230 may discriminate that the operator 310 is in an exercising state when the CO2 (carbon dioxide) concentration in the exhaled breath is equal to or greater than a predetermined threshold value Cth. When the CO2 (carbon dioxide) concentration is less than the threshold Cth, the determination unit 230 may determine that the operator 310 is in a resting state. The CO2 (carbon dioxide) concentration Vs in Fig. 21 is the reference value Vs (described above) when the operator 310 is in an exercising state.

[0183] The discrimination unit 230 (see FIG. 19) may discriminate whether the operator 310 is in an anaerobic exercise state or an aerobic exercise state based on a predetermined relationship between the CO2 (carbon dioxide) concentration in the exhaled breath of the operator 310 and the exhaled breath volume Vb. The predetermined relationship between the CO2 (carbon dioxide) concentration in the exhaled breath and the exhaled breath volume Vb is, for example, the relationship shown in FIG.

[0184] As described above, the exhalation volume Vb (described later) per exhalation tends to increase as the exhalation cycle becomes longer, and tends to decrease as the exhalation cycle becomes shorter. Therefore, the discrimination unit 230 (see FIG. 19) may discriminate whether the operator 310 is in an anaerobic exercise state or an aerobic exercise state based on a predetermined relationship between the CO2 (carbon dioxide) concentration in the exhaled breath of the operator 310 and the exhalation cycle.

[0185] In FIG. 21, the anaerobic exercise state is indicated by a rough dashed line, and the aerobic exercise state is indicated by a dashed line. As the exhalation volume Vb increases, the CO2 (carbon dioxide) concentration is likely to increase. When the exhalation volume Vb is equal to or greater than the exhalation volume Vbc, the operator 310 is likely to be in an anaerobic exercise state. When the exhalation volume Vb is less than the exhalation volume Vbc, the operator 310 is likely to be in an aerobic exercise state. When the CO2 (carbon dioxide) concentration in the exhalation is equal to or greater than the reference value Vs, the operator 310 is likely to be in an anaerobic exercise state. When the CO2 (carbon dioxide) concentration in the exhalation is less than the reference value Vs, the operator 310 is likely to be in an aerobic exercise state. The rate of increase in the CO2 (carbon dioxide) concentration per unit of exhalation volume in the case of anaerobic exercise is likely to be greater than the rate of increase in the CO2 (carbon dioxide) concentration per unit of exhalation volume in the case of aerobic exercise.

[0186] The discrimination unit 230 (see FIG. 19) may discriminate whether the operator 310 is in an anaerobic exercise state or an aerobic exercise state based on the exhalation volume Vbc. The discrimination unit 230 may discriminate that the operator 310 is in an anaerobic exercise state when the exhalation volume Vb is equal to or greater than the exhalation volume Vbc. The discrimination unit 230 may discriminate that the operator 310 is in an aerobic exercise state when the exhalation volume Vb is less than the exhalation volume Vbc. The discrimination unit 230 (see FIG. 19) may discriminate whether the operator 310 is in an anaerobic exercise state or an aerobic exercise state based on the exhalation cycle corresponding to the exhalation volume Vbc.

[0187] The discrimination unit 230 (see FIG. 19) may discriminate whether the operator 310 is in an anaerobic exercise state or an aerobic exercise state based on the reference value Vs. The discrimination unit 230 may determine that the operator 310 is in an anaerobic exercise state when the CO2 (carbon dioxide) concentration in the exhaled breath is equal to or higher than the reference value Vs. The discrimination unit 230 may determine that the operator 310 is in an aerobic exercise state when the CO2 (carbon dioxide) concentration in the exhaled breath is less than the reference value Vs.

[0188] The recognition unit 250 (see FIG. 19 ) recognizes the operator 310. The recognition unit 250 may be provided in a housing of the display unit 210 of an HMD (head mounted) type. The recognition unit 250 recognizes the operator 310, for example, by recognizing the face of the operator 310. The recognition unit 250 may recognize a specific operator 310 among the multiple operators 310.

[0189] The recognition unit 450 (see FIG. 20) recognizes the operator 310. The recognition unit 450 may recognize the operator 310 by recognizing the face of the operator 310. The recognition unit 450 may recognize a specific operator 310 among the multiple operators 310. The control unit 430 (see FIG. 20) may generate recognition information of the operator 310 recognized by the recognition unit 450. The recognition information is referred to as recognition information Ir.

[0190] The transmitting / receiving unit 420 (see FIG. 20) may transmit the recognition information Ir. The transmitting / receiving unit 420 may wirelessly transmit the recognition information Ir. The operation information acquiring unit 240 (see FIG. 19) may acquire the recognition information Ir. The recognizing unit 250 (see FIG. 19) may recognize the operator 310 based on the recognition information Ir.

[0191] The relationship between the CO2 (carbon dioxide) concentration in the exhaled breath and the exhaled breath volume Vb or the exhaled breath cycle may be determined in advance for each of the multiple operators 310. The relationship between the CO2 (carbon dioxide) concentration in the exhaled breath and the exhaled breath volume Vb or the exhaled breath cycle may differ for each operator 310. The relationship between the CO2 (carbon dioxide) concentration in the exhaled breath and the exhaled breath volume Vb or the exhaled breath cycle for each of the multiple operators 310 may be stored in the storage unit 270 (see FIG. 19).

[0192] The discrimination unit 230 (see FIG. 19) may discriminate whether the operator 310 is in an anaerobic exercise state or an aerobic exercise state based on the relationship between the CO2 (carbon dioxide) concentration in the exhaled breath of the operator 310 recognized by the recognition unit 250 and the exhaled breath volume Vb or the exhalation period. In this way, the discrimination unit 230 can discriminate for each operator 310 whether the operator 310 is in an anaerobic exercise state or an aerobic exercise state.

[0193] When the exhalation volume Vb is less than the threshold Vth, the discrimination unit 230 (see FIG. 19) may discriminate the emotion of the operator 310 based on the CO2 (carbon dioxide) concentration in the exhalation. As described above, the case where the exhalation volume Vb is less than the threshold Vth is when the operator 310 is in a resting state. When the exhalation volume Vb is less than the threshold Vth, the CO2 (carbon dioxide) concentration in the exhalation of the operator 310 may depend on the emotion of the operator 310. When the exhalation volume Vb is less than the threshold Vth, if the CO2 (carbon dioxide) concentration in the exhalation of the operator 310 is equal to or greater than the threshold Dth, the discrimination unit 230 may discriminate the state S of the operator 310 as an anxious state, and when the CO2 (carbon dioxide) concentration is less than the threshold Dth, the discrimination unit 230 may discriminate the state S of the operator 310 as a relieved state.

[0194] The biological information acquiring unit 260 (see FIG. 19) acquires biological information of the operator 310. The biological information is referred to as biological information Ig. The biological information Ig may include at least one of heart rate information, sweat rate information, body temperature information, and electromyograph information of the operator 310. The biological information acquiring unit 260 may be provided in a housing of the display unit 210 of an HMD (head mounted) type.

[0195] When the exhaled air volume Vb is less than the threshold value Vth, the discrimination unit 230 (see FIG. 19) may discriminate the emotion of the operator 310 based on the CO2 (carbon dioxide) concentration in the exhaled air and the biological information Ig. For example, when the operator 310 is in an anxious state, the operator 310 is likely to be in a state in which the sympathetic nerves are more dominant than the parasympathetic nerves. When the sympathetic nerves are more dominant than the parasympathetic nerves, the heart rate fluctuation of the operator 310 is likely to be small. For example, when the operator 310 is in a relaxed state, the operator 310 is likely to be in a state in which the parasympathetic nerves are more dominant than the sympathetic nerves. When the parasympathetic nerves are more dominant than the sympathetic nerves, the heart rate fluctuation of the operator 310 is likely to be large.

[0196] The magnitude of the first power spectrum of the heartbeat of the operator 310 is LF, and the magnitude of the second power spectrum is HF. The frequency band of the second power spectrum is a higher frequency band than the frequency band of the first power spectrum. The frequency band of the first power spectrum is, for example, 0.05 Hz or more and less than 0.20 Hz. The frequency band of the second power spectrum is, for example, 0.20 Hz or more and less than 0.35 Hz.

[0197] The biological information acquiring section 260 (see FIG. 19) may acquire LF and HF in the heartbeat of the operator 310. When the ratio of LF to HF (LF / HF) is equal to or greater than a predetermined threshold Nth, the discriminating section 230 (see FIG. 19) may determine that the state S of the operator 310 is a state in which the sympathetic nerves are more dominant than the parasympathetic nerves. When the ratio of LF to HF (LF / HF) is less than the threshold Nth, the discriminating section 230 may determine that the state S of the operator 310 is a state in which the parasympathetic nerves are more dominant than the sympathetic nerves.

[0198] When the state S of the operator 310 is such that the sympathetic nerves are more dominant than the parasympathetic nerves, the exhalation volume Vb of the operator 310 tends to be large or the exhalation cycle tends to be long. When the state S of the operator 310 is such that the parasympathetic nerves are more dominant than the sympathetic nerves, the exhalation volume Vb of the operator 310 tends to be small or the exhalation cycle tends to be short.

[0199] When the operator 310 is in a state of anxiety or fear, and thus the sympathetic nerves are dominant over the parasympathetic nerves, the operator 310 may be in a state of respiratory alkalosis. A state of respiratory alkalosis is a state in which CO2 (carbon dioxide) is excessively discharged due to hyperventilation or the like. When the operator 310 is in a state of respiratory alkalosis, the heart rate, sweat rate, and respiratory rate of the operator 310 are likely to increase, the muscles are likely to stiffen, the body temperature (particularly the body temperature of the hands and feet) is likely to decrease, and the end-tidal carbon dioxide concentration is likely to decrease. That is, when the operator 310 is in a state of anxiety or fear, the heart rate, sweat rate, and respiratory rate are likely to increase, the amplitude of the myoelectric potential is likely to increase, and the CO2 (carbon dioxide) concentration in the expired air is likely to decrease.

[0200] When the operator 310 is excited, angry, or highly aggressive, the operator 310 may be in a state of respiratory acidosis. The state of respiratory acidosis is a state in which CO2 (carbon dioxide) accumulates due to a deterioration in respiratory condition. When the operator 310 is in a state of respiratory acidosis, the body temperature (particularly the temperature of the head, chest, or hands) is likely to rise, and the end-tidal carbon dioxide concentration is likely to rise. In other words, when the operator 310 is excited, angry, or highly aggressive, the heart rate and sweat rate are likely to increase, the respiratory rate and respiratory volume Vb are likely to decrease, and the CO2 (carbon dioxide) concentration in the exhaled air is likely to increase.

[0201] The discrimination unit 230 may discriminate whether the exhalation volume Vb of the operator 310 is equal to or greater than the threshold value Vth or less than the threshold value Vth based on the biological information Ig. The discrimination unit 230 may discriminate the emotion of the operator 310 based on the discriminated exhalation volume Vb and the concentration of CO2 (carbon dioxide) in the exhaled breath.

[0202] The discrimination unit 230 (see FIG. 19 ) may discriminate an application currently running on the display device 300. The discrimination unit 230 may discriminate the type of application currently running on the display device 300. The discrimination unit 230 may discriminate the state S of the operator 310 based on the discriminated application. For example, if the application currently running on the display device 300 is an application related to exercise, such as running or walking, the state S of the operator 310 is highly likely to be an exercise state. For example, if the application currently running on the display device 300 is not an application related to exercise, such as Go, Shogi, or Chess, the state S of the operator 310 is highly likely to be a resting state. For this reason, the discrimination unit 230 can discriminate the state S of the operator 310 based on the application.

[0203] The discrimination unit 230 may discriminate the type of application currently running on the display device 300. The type of application may be, for example, whether the application is an application that is closely related to exercise, such as running or walking, or an application that is less related to exercise, such as Go, Japanese chess, or chess. An application that is closely related to exercise is an application that is highly likely to cause the operator 310 to be in an exercise state when the operator 310 uses the application. An application that is less related to exercise is an application that is highly likely to cause the operator 310 to be in a resting state while the operator 310 uses the application. The discrimination unit 230 may estimate the state of the operator 310 based on the discriminated type of application. The discrimination unit 230 may estimate whether the state of the operator 310 is in an exercise state or a resting state based on the discriminated type of application.

[0204] The determination unit 230 may determine whether the state S of the operator 310 based on the CO2 (carbon dioxide) concentration acquired by the CO2 (carbon dioxide) sensor 220 matches the state of the operator 310 estimated based on the type of application. When the state S of the operator 310 based on the CO2 (carbon dioxide) concentration differs from the state of the operator 310 estimated based on the type of application, the display unit 210 may display information prompting the operator to end the running application. For example, if the state S based on the CO2 (carbon dioxide) concentration is an exercise state even though the state estimated based on the type of application is a resting state, the operator 310 may be playing Go on a smartphone while walking, for example. For this reason, the behavior of the operator 310 may be a nuisance to those around him. For this reason, the display unit 210 may display information prompting the operator to end the running application.

[0205] For example, if the application is an application that acquires workout information such as running, the discrimination unit 230 may discriminate the application as an application closely related to exercise. The discrimination unit 230 may estimate the state of the operator 310 to be an exercise state based on the type of the application. If the discrimination unit 230 estimates the state of the operator 310 to be an exercise state based on the type of application, but the state S based on the CO2 (carbon dioxide) concentration is a resting state, the operator 310 may not be exercising sufficiently. For this reason, the display unit 210 may display information for the operator 310 to start exercising, or information encouraging the operator 310 to exercise.

[0206] The CO2 (carbon dioxide) concentration acquired by the CO2 (carbon dioxide) sensor 220 may be calculated in the control unit 290 (see FIG. 19) or may be calculated in an application installed in the display device 300. The CO2 (carbon dioxide) concentration acquired by the CO2 (carbon dioxide) sensor 220 may be transmitted to the device 400 by the transmission unit 280 (see FIG. 19), and the transmission / reception unit 420 (see FIG. 20) may receive the CO2 (carbon dioxide) concentration. The control unit 430 (see FIG. 20) may calculate the CO2 (carbon dioxide) concentration. The transmission / reception unit 420 (see FIG. 20) may transmit the calculated CO2 (carbon dioxide) concentration. The operation information acquisition unit 240 (see FIG. 19) may receive the CO2 (carbon dioxide) concentration transmitted by the transmission / reception unit 420. The determination unit 230 may determine the state S of the operator 310 based on the operation information Ip (see FIG. 19) and the CO2 (carbon dioxide) concentration acquired by the operation information acquisition unit 240.

[0207] In the case where the display device 300 includes a plurality of CO2 (carbon dioxide) sensors 220, one CO2 (carbon dioxide) sensor 220 may acquire the CO2 (carbon dioxide) concentration of the breath accompanied by the vocalization of the operator 310, and the other CO2 (carbon dioxide) sensor 220 may acquire the CO2 (carbon dioxide) concentration of the breath not accompanied by the vocalization of the operator 310. In the example of Fig. 17, the CO2 (carbon dioxide) sensor 220-2 acquires the CO2 (carbon dioxide) concentration of the breath accompanied by the vocalization of the operator 310, and the CO2 (carbon dioxide) sensor 220-1 acquires the CO2 (carbon dioxide) concentration of the breath not accompanied by the vocalization of the operator 310.

[0208] The display device 300 may include a voice acquisition unit that acquires the speech of the operator 310. In the example of FIG. 17, the CO2 (carbon dioxide) sensor 220-2 may be included in the voice acquisition unit. The CO2 (carbon dioxide) sensor 220-2 may be disposed closer to the mouth of the operator 310 than the CO2 (carbon dioxide) sensor 220-1. The CO2 (carbon dioxide) sensor 220-1 may be disposed farther away from the mouth of the operator 310 than the CO2 (carbon dioxide) sensor 220-2. In the example of FIG. 17, the CO2 (carbon dioxide) sensor 220-1 is disposed above the head of the operator 310.

[0209] The CO2 (carbon dioxide) sensor 220-1 may be separated from the display device 300 and installed in a room where the operator 310 is present. When the CO2 (carbon dioxide) sensor 220-1 is installed in a room where the operator 310 is present, the CO2 (carbon dioxide) concentration measured by the CO2 (carbon dioxide) sensor 220-1 may be wirelessly transmitted to the display device 300.

[0210] The discrimination unit 230 (see FIG. 19) may discriminate the state S of the operator 310 based on the CO2 (carbon dioxide) concentration acquired by one CO2 (carbon dioxide) sensor 220 and the CO2 (carbon dioxide) concentration acquired by the other CO2 (carbon dioxide) sensor 220. The difference between the CO2 (carbon dioxide) concentration acquired by one CO2 (carbon dioxide) sensor 220 and the CO2 (carbon dioxide) concentration acquired by the other CO2 (carbon dioxide) sensor 220 is set as a difference d. The discrimination unit 230 may discriminate the state S of the operator 310 based on the difference d.

[0211] When the difference d is equal to or greater than the threshold dth, the discrimination unit 230 may determine that the state S of the operator 310 is an excited state. When the operator 310 is excited, the difference d is likely to be large. When the difference d is less than the threshold dth, the discrimination unit 230 may determine that the state S of the operator 310 is a relaxed state. When the operator 310 is relaxed, the difference d is likely to be small.

[0212] Fig. 22 is a flowchart showing an example of a display method according to an embodiment of the present invention. A display method according to an embodiment of the present invention will be described taking the display device shown in Fig. 19 as an example. The display method includes a CO2 (carbon dioxide) concentration acquisition step S200 and a display step S210. The display method may include an exhaled air volume acquisition step S201, a biological information acquisition step S202, an operation information acquisition step S204, a recognition step S206, a discrimination step S208, a control step S1102, a control step S212, a judgment step S214, and a judgment step S216.

[0213] The CO2 (carbon dioxide) concentration acquisition step S200 is a step in which the CO2 (carbon dioxide) sensor 220 acquires the CO2 (carbon dioxide) concentration in the breath of the operator 310 who operates the head-mounted display unit 210. The display step S210 is a step in which the display unit 210 displays the state S of the operator 310 based on the CO2 (carbon dioxide) concentration.

[0214] The determination step S208 may be a step in which the determination unit 230 determines the state S of the operator 310 based on the CO2 (carbon dioxide) concentration acquired in the CO2 (carbon dioxide) concentration acquisition step S200. The display step S210 may be a step in which the display unit 210 displays the state S of the operator 310 based on the CO2 (carbon dioxide) concentration determined in the determination step S208.

[0215] The display step S210 may include a control step S2102. The control step S2102 may be a step in which the control unit 290 controls the display unit 210 based on the state S of the operator 310 determined in the determination step S208. The control step S2102 may be a step in which the control unit 290 controls the display unit 210 based on the CO2 (carbon dioxide) concentration acquired in the CO2 (carbon dioxide) concentration acquisition step S200 and a reference value Vs of the CO2 (carbon dioxide) concentration.

[0216] In the judgment step S214, the discrimination unit 230 judges whether to acquire the CO2 (carbon dioxide) concentration after the control step S2102. If it is judged that the CO2 (carbon dioxide) concentration is to be acquired, the display method returns to the CO2 (carbon dioxide) concentration acquisition step S200. If it is judged that the CO2 (carbon dioxide) concentration is not to be acquired, the display method is terminated.

[0217] After controlling the display unit 210 based on the CO2 (carbon dioxide) concentration and the reference value Vs in the control step S2102, the CO2 (carbon dioxide) concentration acquisition step S200 may be a step in which the CO2 (carbon dioxide) sensor 220 further acquires the CO2 (carbon dioxide) concentration. The control step S2102 may be a step in which the control unit 290 controls the display unit 210 based on a change from the CO2 (carbon dioxide) concentration before controlling the display unit 210 to the CO2 (carbon dioxide) concentration after controlling the display unit 210.

[0218] The control step S212 may be a step in which the control unit 290 controls the device 400 used by the operator 310 based on the state S of the operator 310 determined in the determination step S208. The control step S212 may be a step in which the control unit 290 controls the device 400 based on the CO2 (carbon dioxide) concentration acquired in the CO2 (carbon dioxide) concentration acquisition step S200 and a reference value Vs of the CO2 (carbon dioxide) concentration.

[0219] In the judgment step S216, the discrimination unit 230 judges whether or not to acquire the CO2 (carbon dioxide) concentration after the control step S212. If it is judged that the CO2 (carbon dioxide) concentration is to be acquired, the display method returns to the CO2 (carbon dioxide) concentration acquisition step S200. If it is judged that the CO2 (carbon dioxide) concentration is not to be acquired, the display method is terminated.

[0220] After controlling the device 400 based on the CO2 (carbon dioxide) concentration and the reference value Vs in the control step S212, the CO2 (carbon dioxide) concentration acquisition step S200 may be a step in which the CO2 (carbon dioxide) sensor 220 further acquires the CO2 (carbon dioxide) concentration. The control step S212 may be a step in which the control unit 290 controls the device 400 based on a change from the CO2 (carbon dioxide) concentration before controlling the device 400 to the CO2 (carbon dioxide) concentration after controlling the device 400.

[0221] The operation information acquisition step S204 is a step in which the operation information acquisition unit 240 acquires operation information Ip of the device 400 by the operator 310. The determination step S208 may be a step in which the determination unit 230 determines the state S of the operator 310 based on the CO2 (carbon dioxide) concentration and the operation information Ip. When the device 400 is an exercise machine, the display step S210 may be a step in which the display unit 210 displays a response to the operation of the device 400 by the operator 310 based on the state S of the operator 310 based on the CO2 (carbon dioxide) concentration determined in the determination step 208 and the operation information Ip.

[0222] The exhalation volume acquisition step S201 is a step in which the exhalation volume sensor 224 further acquires the exhalation volume Vb or the exhalation cycle of the operator 310. The determination step S208 may be a step in which the determination unit 230 determines the state S of the operator 310 based on the CO2 (carbon dioxide) concentration and the exhalation volume Vb or the exhalation cycle. The determination step S208 may be a step in which the determination unit 230 determines whether the operator 310 is in an anaerobic exercise state or an aerobic exercise state based on a predetermined relationship between the CO2 (carbon dioxide) concentration and the exhalation volume Vb or the exhalation cycle.

[0223] The recognition step S206 is a step in which the recognition unit 250 recognizes the operator 310. The relationship between the CO2 (carbon dioxide) concentration and the exhalation volume Vb or the exhalation cycle may be determined in advance for each of the multiple operators 310. The determination step S208 may be a step in which the discrimination unit 230 discriminates whether the recognized operator 310 is in an anaerobic exercise state or an aerobic exercise state based on the relationship between the CO2 (carbon dioxide) concentration and the exhalation volume Vb or the exhalation cycle in the operator 310 recognized in the recognition step S206. When the exhalation volume Vb is less than the threshold value Vth, the discrimination step S208 may be a step in which the discrimination unit 230 discriminates the emotion of the operator 310 based on the CO2 (carbon dioxide) concentration.

[0224] The biological information acquiring step S202 is a step in which the biological information acquiring section 260 acquires the biological information Ig of the operator 310. The determining step S208 may be a step in which the determining section 230 determines the emotion of the operator 310 based on the CO2 (carbon dioxide) concentration and the biological information Ig.

[0225] The determining step S208 may be a step in which the determining unit 230 determines an application currently running on the display device 300, and determines the state S of the operator 310 based on the determined application.

[0226] The determination step S208 may be a step in which the determination unit 230 determines the type of application being activated by the display device 300. The determination step S208 may be a step in which the determination unit 230 determines whether the state S of the operator 310 based on the CO2 (carbon dioxide) concentration acquired by the CO2 (carbon dioxide) sensor 220 matches the state of the operator 310 estimated based on the type of application. The display step S210 may be a step in which the display unit 210 displays information prompting the operator to end the activated application when the state S of the operator 310 based on the CO2 (carbon dioxide) concentration differs from the state of the operator 310 estimated based on the type of application.

[0227] The CO2 (carbon dioxide) concentration acquisition step S200 may be a step in which one CO2 (carbon dioxide) sensor 220-2 acquires a CO2 (carbon dioxide) concentration of the breath accompanied by vocalization of the operator 310, and the other CO2 (carbon dioxide) sensor 220-1 acquires a CO2 (carbon dioxide) concentration of the breath not accompanied by vocalization of the operator 310. The determination step S208 may be a step in which the determination unit 230 determines the state S of the operator 310 based on the CO2 (carbon dioxide) concentration acquired by the one CO2 (carbon dioxide) sensor 220-2 and the CO2 (carbon dioxide) concentration acquired by the other CO2 (carbon dioxide) sensor 220-1.

[0228] 23 is a diagram showing an example of a computer 2200 in which the breath detection system 100 or the display device 300 according to an embodiment of the present invention may be entirely or partially embodied. A program installed in the computer 2200 can cause the computer 2200 to function as an operation associated with the breath detection system 100 or the display device 300 according to an embodiment of the present invention, or one or more sections of the breath detection system 100 or the display device 300, or can cause the computer 2200 to execute the operation or one or more sections, or can cause the computer 2200 to execute each step (see FIG. 10, FIG. 11, FIG. 22) according to the display method of the present invention. The program can be executed by the CPU 2212 to cause the computer 2200 to execute specific operations associated with some or all of the blocks in the flowcharts (FIG. 10, FIG. 11, FIG. 22) and block diagrams (FIG. 13, FIG. 16, FIG. 19) described in this specification.

[0229] A computer 2200 according to an embodiment of the present invention includes a CPU 2212, a RAM 2214, a graphic controller 2216, and a display device 2218. The CPU 2212, the RAM 2214, the graphic controller 2216, and the display device 2218 are connected to each other by a host controller 2210. The computer 2200 further includes input / output units such as a communication interface 2222, a hard disk drive 2224, a DVD-ROM drive 2226, and an IC card drive. The communication interface 2222, the hard disk drive 2224, the DVD-ROM drive 2226, and the IC card drive are connected to the host controller 2210 via an input / output controller 2220. The computer further includes legacy input / output units such as a ROM 2230 and a keyboard 2242. The ROM 2230, the keyboard 2242, and the like are connected to the input / output controller 2220 via an input / output chip 2240.

[0230] The CPU 2212 controls each unit by operating according to programs stored in the ROM 2230 and the RAM 2214. The graphic controller 2216 acquires image data generated by the CPU 2212 into a frame buffer or the like provided in the RAM 2214 or into the RAM 2214, thereby causing the image data to be displayed on the display device 2218.

[0231] The communication interface 2222 communicates with other electronic devices via a network. The hard disk drive 2224 stores programs and data used by the CPU 2212 in the computer 2200. The DVD-ROM drive 2226 reads programs or data from the DVD-ROM 2201 and provides the read programs or data to the hard disk drive 2224 via the RAM 2214. The IC card drive reads programs and data from an IC card or writes programs and data to an IC card.

[0232] The ROM 2230 stores a boot program or the like that is executed by the computer 2200 upon activation, or a program that depends on the hardware of the computer 2200. The input / output chip 2240 may connect various input / output units to the input / output controller 2220 via a parallel port, a serial port, a keyboard port, a mouse port, or the like.

[0233] The programs are provided by a computer-readable medium such as a DVD-ROM 2201 or an IC card. The programs are read from the computer-readable medium, installed in the hard disk drive 2224, the RAM 2214, or the ROM 2230, which are also examples of computer-readable media, and executed by the CPU 2212. Information processing described in these programs is read by the computer 2200, and brings about cooperation between the programs and the various types of hardware resources described above. An apparatus or method may be constructed by implementing information manipulation or processing according to the use of the computer 2200.

[0234] For example, when communication is performed between the computer 2200 and an external device, the CPU 2212 may execute a communication program loaded in the RAM 2214 and instruct the communication interface 2222 to perform communication processing based on the processing described in the communication program. Under the control of the CPU 2212, the communication interface 2222 reads transmission data stored in a transmission buffer processing area provided in the RAM 2214, the hard disk drive 2224, the DVD-ROM 2201, or a recording medium such as an IC card, and transmits the read transmission data to a network, or writes reception data received from the network to a reception buffer processing area or the like provided on the recording medium.

[0235] The CPU 2212 may cause all or a necessary portion of a file or database stored in an external recording medium such as the hard disk drive 2224, the DVD-ROM drive 2226 (DVD-ROM 2201), an IC card, etc. to be read into the RAM 2214. The CPU 2212 may perform various types of processing on the data on the RAM 2214. The CPU 2212 may then write back the processed data to the external recording medium.

[0236] Various types of information, such as various types of programs, data, tables, and databases, may be stored in the recording medium and processed. The CPU 2212 may execute various types of processing on the data read from the RAM 2214, including various types of operations, information processing, conditional decisions, conditional branches, unconditional branches, information searches or replacements, etc., specified by the instruction sequences of the programs described in this disclosure. The CPU 2212 may write back the results to the RAM 2214.

[0237] CPU2212 may search for information in a file, database, etc. in the recording medium. For example, when a plurality of entries each having an attribute value of a first attribute associated with an attribute value of a second attribute are stored in the recording medium, CPU2212 may search for an entry that matches a condition in which the attribute value of the first attribute is specified from among the plurality of entries, read the attribute value of the second attribute stored in the entry, and obtain the attribute value of the second attribute associated with the first attribute that satisfies a predetermined condition by reading the second attribute value.

[0238] The above-mentioned program or software module may be stored on the computer 2200 or in a computer-readable medium of the computer 2200. A recording medium such as a hard disk or a RAM provided in a server system connected to a dedicated communication network or the Internet can be used as the computer-readable medium. The program may be provided to the computer 2200 by the recording medium.

[0239] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the description of the claims that such modifications and improvements can also be included in the technical scope of the present invention. [Item 1-1] A main body portion, A breath sensor provided in the main body, having two operation modes with different power consumption, for detecting breath; A control unit that controls an operation mode of the breath sensor based on a state of at least one of the main body unit and the breath sensor; A breath detection system comprising: [Item 1-2] The main body portion is A fixed portion; A movable part that is movable relative to the fixed part and has the breath sensor provided thereon; having The control unit controls the operation mode of the breath sensor based on the state of the movable unit. The breath detection system according to item 1-1. [Item 1-3] The breath detection system described in item 1-2, wherein the movable part has a sound detection part that detects sound. [Item 1-4] The main body portion has a sound detection portion that detects sound, The control unit controls the operation mode of the breath sensor based on the state of the sound detected by the sound detection unit. The breath detection system according to item 1-1. [Items 1-5] The main body portion has a temperature detection portion that detects a temperature, The control unit controls the operation mode of the breath sensor based on the temperature detected by the temperature detection unit. The breath detection system according to item 1-1. [Items 1-6] The main body has a distance detection unit that detects a distance to another object, The control unit controls the operation mode of the breath sensor based on the distance detected by the distance detection unit. The breath detection system according to item 1-1. [Items 1-7] The state of the main body is changed by a control signal from application software. The control unit controls the operation mode of the breath sensor based on the control signal. The breath detection system according to item 1-1. [Items 1-8] The main body has a storage battery for supplying power, The control unit controls the operation mode of the breath sensor based on the remaining capacity of the storage battery. The breath detection system according to item 1-1. [Items 1-9] the main body has a plurality of operating states with different power consumptions, The control unit controls the operation mode of the breath sensor based on the operation state of the main body unit. The breath detection system according to item 1-1. [Items 1-10] The control unit controls the operating mode of the breath sensor based on the breath detected by the breath sensor. [Item 1-11] The breath sensor has, as the operation mode, an active state in which breath can be detected, and a standby state in which power consumption is lower than that of the active state, The control unit controls the operation mode of the breath sensor based on a state of the main body unit. A breath detection system according to any one of items 1-1 to 1-10. [Item 1-12] The control unit controls the operation mode of the breath sensor by comparing a state value indicating a state of the main body unit with a set reference value; the reference value when the breath sensor is transitioned from the active state to the standby state is different from the reference value when the breath sensor is transitioned from the standby state to the active state; Item 1-11. A breath detection system according to any one of claims 1 to 11. [Items 1-13] the main body portion has a plurality of types of the state, and each type of the state is changeable; The control unit controls the state of the breath sensor based on the different types of states of the main body when transitioning the breath sensor from the active state to the standby state and when transitioning the breath sensor from the standby state to the active state. Item 1-11. A breath detection system according to any one of claims 1 to 11. [Items 1-14] The control unit adjusts a determination criterion for the state of the main body when controlling the operation mode of the breath sensor this time based on the state of the main body used for determination when the operation mode of the breath sensor was controlled last time. Item 1-11. A breath detection system according to any one of claims 1 to 11. [Items 1-15] the main body portion has a plurality of types of the state, and each type of the state is changeable; The control unit controls the operation mode of the breath sensor based on two or more types of the states of the main body unit. A breath detection system according to any one of items 1-1 to 1-10. [Items 1-16] The breath sensor includes: A light emitting unit that irradiates light toward a path through which the exhaled breath passes; a first light receiving unit that receives at least a portion of the light emitted by the light emitting unit and outputs a first light receiving signal according to a result of the light receiving; The breath detection system according to any one of items 1-1 to 1-10, comprising: [Item 2-1] A head-mounted display unit; a carbon dioxide sensor for acquiring a carbon dioxide concentration in the breath of an operator of the display unit; A display device comprising: [Item 2-2] A determination unit that determines a state of the operator based on the carbon dioxide concentration, The display unit displays the state of the operator determined by the determination unit. The display device according to item 2-1. [Item 2-3] The display device according to item 2-2, further comprising a control unit that controls the display unit based on the state of the operator determined by the determination unit. [Item 2-4] The display device according to item 2-3, wherein the control unit controls the display unit based on the carbon dioxide concentration and a reference value of the carbon dioxide concentration corresponding to a state of the operator. [Item 2-5] The carbon dioxide sensor further acquires the carbon dioxide concentration after the control unit controls the display unit based on the carbon dioxide concentration and the reference value, The control unit controls the display unit based on a change in the carbon dioxide concentration from a state before controlling the display unit to a state after controlling the display unit. The display device according to item 2-4. [Item 2-6] A determination unit that determines a state of the operator based on the carbon dioxide concentration; A control unit that controls a device used by the operator based on the state of the operator determined by the determination unit; The display device according to item 2-1, further comprising: [Item 2-7] The display device according to item 2-6, wherein the control unit controls the device based on the carbon dioxide concentration and a reference value of the carbon dioxide concentration corresponding to the state of the operator. [Item 2-8] The carbon dioxide sensor further acquires the carbon dioxide concentration after the control unit controls the device based on the carbon dioxide concentration and the reference value, The control unit further controls the device based on a change in the carbon dioxide concentration from before controlling the device to the carbon dioxide concentration after controlling the device. Item 2-7. The display device according to item 2-7. [Item 2-9] the equipment is exercise equipment; An operation information acquisition unit that acquires operation information of the device by the operator, The display unit displays a response to an operation of the device by the operator based on the state of the operator based on the carbon dioxide concentration determined by the determination unit and the operation information. The display device according to any one of items 2 to 6. [Item 2-10] An exhalation volume sensor for acquiring an exhalation volume of the operator is further provided, The determination unit determines a state of the operator based on the carbon dioxide concentration and the exhaled air volume. The display device according to item 2-2 or 2-6. [Item 2-11] The display device according to item 2-10, wherein the discrimination unit discriminates whether the operator is in an anaerobic exercise state or an aerobic exercise state based on a predetermined relationship between the carbon dioxide concentration and the exhaled air volume. [Item 2-12] A recognition unit that recognizes the operator is further provided, the relationship is determined in advance for each of the multiple operators; the determination unit determines whether the operator recognized by the recognition unit is in an anaerobic exercise state or an aerobic exercise state based on the relationship of the operator recognized by the recognition unit. The display device according to any one of items 2-11. [Item 2-13] The display device according to item 2-10, wherein when the amount of exhaled air is less than a predetermined threshold, the discrimination unit discriminates the emotion of the operator based on the carbon dioxide concentration. [Item 2-14] a biometric information acquisition unit for acquiring biometric information of the operator, The determination unit determines an emotion of the operator based on the carbon dioxide concentration and the biological information. The display device according to item 2-13. [Item 2-15] The determination unit further determines a type of an application currently running on the display device, and estimates a state of the operator based on the determined type of the application; The display device described in item 2-2 or 2-6, wherein the display unit displays information prompting the operator to terminate the running application when the state of the operator based on the carbon dioxide concentration determined by the determination unit differs from the state of the operator estimated based on the type of the application. [Item 2-16] an acquisition step in which a carbon dioxide sensor acquires a carbon dioxide concentration in the breath of an operator who operates a head-mounted display unit; a display step in which the display unit displays a state of the operator based on the carbon dioxide concentration; A display method comprising: [Item 2-17] A display program for causing a computer to function as a display device according to any one of items 2-1 to 2-9. [Explanation of symbols]

[0240] REFERENCE SIGNS LIST 10 breath sensor, 11 gas sensor, 12 path, 14 light, 16 light emitting unit, 18 first light receiving unit, 20 calculation unit, 22 second light receiving unit, 24 optical filter, 30 support member, 32 mirror, 40 substrate, 41 first main surface, 42 second main surface, 44 light emitting element, 100 breath detection system, 102 main body, 110 fixed unit, 111 connection unit, 112 sound generating unit, 113 arm portion, 117 storage battery, 120 movable portion, 122 sound detection portion, 140 control portion, 150 status detection portion, 151 position status detection portion, 152 environmental status detection portion, 153 operation status detection portion, 154 wearing detection portion, 155 signal detection portion, 156 remaining capacity detection portion, 157 power consumption detection portion, 200 user, 210 display portion, 212 housing, 214 bottom surface, 220 CO 2 (carbon dioxide) sensor, 222.... mouth opening, 224.... breath volume sensor, 230.... discrimination unit, 240.... operation information acquisition unit, 250.... recognition unit, 260.... biological information acquisition unit, 270.... storage unit, 280.... transmission unit, 290.... control unit, 300.... display device, 310.... operator, 400.... device, 410.... display unit, 420.... transmission / reception unit, 430.... control unit, 440.... operation unit, 450.... recognition unit, 2200.... computer computer, 2201...DVD-ROM, 2210...host controller, 2212...CPU, 2214...RAM, 2216...graphics controller, 2218...display device, 2220...input / output controller, 2222...communication interface, 2224...hard disk drive, 2226...DVD-ROM drive, 2230...ROM, 2240...input / output chip, 2242...keyboard

Claims

1. An exhalation sensor for detecting exhaled air generated by breathing, A light emitting unit that irradiates light toward a path through which the exhaled breath passes; a first light receiving unit that receives at least a part of the light emitted by the light emitting unit and outputs a first light receiving signal according to a result of the light receiving; A calculation unit that performs a calculation on the first light receiving signal; Equipped with The calculation unit calculates a baseline of a waveform of the first light receiving signal based on a frequency component of the first light receiving signal that is lower than a first cutoff frequency that is set, and detects the exhalation based on a signal obtained by removing the baseline from the first light receiving signal. Breath sensor.

2. The calculation unit calculates at least one of a period and a length of the breathing. The breath sensor according to claim 1 .

3. The breath sensor according to claim 1 , wherein the first cutoff frequency is set in response to a change in a signal value of the first light receiving signal.

4. The calculation unit sets the first cutoff frequency when the signal value of the first light receiving signal, which is the target for calculating the baseline value, is increased relative to a past signal value in a time waveform of the first light receiving signal, higher than the first cutoff frequency when the signal value is decreased relative to the past signal value. The breath sensor according to claim 1 .

5. The calculation unit sets the first cutoff frequency when the signal value of the first light receiving signal, for which the baseline value is to be calculated, has increased by 20% or more compared to a past signal value in a time waveform of the first light receiving signal, higher than the first cutoff frequency when the signal value has decreased by 20% or more compared to the past signal value. The breath sensor according to claim 4.

6. The calculation unit sets the first cutoff frequency when the signal value of the first light receiving signal, which is the target for calculating the baseline value, increases with respect to the signal value at a previous timing in the time waveform of the first light receiving signal, to be 10 times or more higher than the first cutoff frequency when the signal value decreases with respect to the previous signal value. The breath sensor according to claim 4.

7. The calculation unit sets the first cutoff frequency when the signal value of the first light receiving signal, for which the baseline value is to be calculated, has increased by 20% or more compared to the signal value at an immediately preceding timing in the time waveform of the first light receiving signal, to be 10 times or more higher than the first cutoff frequency when the signal value has decreased by 20% or more compared to the immediately preceding signal value. The breath sensor according to claim 6.

8. The first cutoff frequency is less than or equal to 3 Hz. The breath sensor according to claim 6.

9. a second light receiving unit that receives the light that has not passed through the path through which the exhaled air passes, out of the light emitted by the light emitting unit, and outputs a second light receiving signal according to a light receiving result; The calculation unit corrects the first light receiving signal based on a signal value of the second light receiving signal. The breath sensor according to any one of claims 1 to 8.

10. the calculation unit generates the first light receiving signal after correction by using a frequency component of the second light receiving signal lower than a set second cutoff frequency and a frequency component of the first light receiving signal lower than a set third cutoff frequency; The second cutoff frequency is lower than the third cutoff frequency. The breath sensor according to claim 9.

11. an optical filter disposed on an optical path of the light between the light emitting section and the first light receiving section, the optical filter limiting a wavelength of the light incident on the first light receiving section; The breath sensor according to claim 6.

12. A gas sensor for detecting a detection target gas, a light emitting unit that irradiates light toward a path through which the detection target gas passes; a first light receiving unit that receives at least a part of the light emitted by the light emitting unit and outputs a first light receiving signal according to a result of the light receiving; A calculation unit that performs a calculation on the first light receiving signal; Equipped with the calculation unit calculates a baseline of a waveform of the first light receiving signal based on a frequency component of the first light receiving signal that is lower than a first cutoff frequency that is set, and detects the target gas based on a signal obtained by removing the baseline from the first light receiving signal. Gas sensor.

13. A breath detection method for detecting breath generated by breathing, comprising: a light emitting step in which a light emitting unit irradiates light toward a path through which the exhaled breath passes; a first light receiving step in which a first light receiving unit receives at least a part of the light irradiated in the light emitting step; a first output step in which the first light receiving unit outputs a first light receiving signal according to a result of light receiving in the first light receiving step; a calculation step in which a calculation unit performs a calculation on the first light receiving signal output in the first output step; Equipped with The calculation step includes: a calculation step of calculating a baseline of a waveform of the first light receiving signal based on a frequency component of the first light receiving signal that is lower than a first cutoff frequency that is set by the calculation unit; a detection step in which the calculation unit detects the exhalation based on a signal obtained by removing the baseline calculated in the calculation step from the first light receiving signal; have Breath detection methods.

Images