WO2020032055A1

WO2020032055A1 - Water level detection device and humidification device

Info

Publication number: WO2020032055A1
Application number: PCT/JP2019/030958
Authority: WO
Inventors: 浩平森田
Original assignee: シャープ株式会社
Priority date: 2018-08-10
Filing date: 2019-08-06
Publication date: 2020-02-13
Also published as: JP7143418B2; CN112534217A; JPWO2020032055A1

Abstract

This water level detection device is capable of detecting a water level more accurately than conventional products. In a range sensor (10), a light-emitting part (110) emits detection light (L1) to a prescribed position on the surface of water in a water storage tray (90). A light-receiving part (120) receives reflection light (L2) of the detection light (L1) reflected at the prescribed position. A first control unit (15) calculates, on the basis of the detection light (L1) and the reflection light (L2), a water level detection value which is a value of the water level detected in the water storage tray (90). The first control unit (15) further corrects the water level detection value in accordance with the rate of air flow in the water storage tray (90).

Description

Water level detector and humidifier

の一 One embodiment of the present invention relates to a water level detection device that detects a water level in a container.

In recent years, various proposals have been made regarding the configuration of the water level detection device. For example, Patent Literature 1 discloses a technique for determining whether or not a water level is equal to or higher than a predetermined water level by a simple configuration of a water level detection device.

Japanese Unexamined Patent Publication "JP-A-2016-99256"

However, as will be described later, there is still room for improvement in improving the detection accuracy of the water level detection device. An object of one embodiment of the present invention is to detect a water level more accurately than in a conventional water level detection device.

In order to solve the above problems, a water level detection device according to one embodiment of the present invention is a water level detection device that detects a water level in a container, and emits detection light to a predetermined position on a water surface in the container. A light-emitting unit, a light-receiving unit that receives reflected light that is light in which the detection light is reflected at the predetermined position, and a calculation device, wherein the calculation device is based on the detection light and the reflection light. Then, a water level detection value, which is a detection value of the water level, is calculated, and the water level detection value is corrected according to the air volume in the container.

According to the water level detection device according to one embodiment of the present invention, the water level can be detected more accurately than in the past.

It is a figure showing the outline of the humidification device of Embodiment 1. It is a functional block diagram which shows the structure of the principal part of the humidifier of FIG. (A) And (b) is a figure for demonstrating the relationship between the air volume and the measurement accuracy of a distance measuring sensor, respectively. FIG. 9 is a diagram illustrating an example of a shift value setting table. (A) And (b) is a figure for each explaining the result of one study by the inventor. (A)-(c) is a figure for each explaining another examination result by the inventor.

[Embodiment 1]
The humidifier 1 according to the first embodiment will be described below. For convenience of description, in the following embodiments, members having the same functions as the members described in Embodiment 1 will be denoted by the same reference numerals, and description thereof will not be repeated. In addition, description of the same matters as those in the known art will be appropriately omitted. It should be noted that each drawing is intended to schematically explain the shape, structure, positional relationship, and the like of each member, and is not necessarily drawn to scale.

(Humidifier 1)
FIG. 1 is a diagram showing an outline of the humidifying device 1. FIG. 2 is a functional block diagram illustrating a configuration of a main part of the humidifying device 1. In the following description, the upward direction in the drawing and the downward direction in the drawing of FIG. 1 are referred to as a vertical upward direction and a vertical downward direction, respectively. However, the position and the arrangement direction of each part of the humidifier 1 are not limited to the example of FIG.

The humidifying device 1 includes a distance measuring sensor 10 (water level detecting device) and a water storage tray 90 (container). The water storage tray 90 is an example of a container that receives the water WT. The water storage tray 90 is housed in the housing 80 of the humidifier 1. As described below, the distance measuring sensor 10 optically detects the water level (WL in FIG. 1) of the water WT in the water storage tray 90. The distance measuring sensor 10 is arranged at a predetermined position in the housing 80. More specifically, the distance measuring sensor 10 is arranged at a position higher than the top of the housing 80 with reference to the bottom surface inside the housing 80. H in FIG. 1 shows the height of the distance measurement sensor 10 with reference to the bottom surface inside the housing 80. H is set as a value larger than the height of the housing 80.

The housing 80 is provided with a water supply port 81, a water supply path 82, and a discharge port 83. When the user of the humidifier 1 pours the water WT into the water supply port 81, the water WT can be refilled into the water storage tray 90 via the water supply path 82. In the humidifier 1, a fan 71 is provided in the housing 80. A humidification filter 72 is provided in the water storage tray 90. The humidification filter 72 absorbs a part of the water WT in the water storage tray 90. By operating the fan 71, the wind WD can be generated in the housing 80. When the wind WD passes through the humidification filter 72, a part of the water WT contained in the humidification filter 72 is released into the air blown by the fan 71. That is, the air can be humidified. The wind WD that has passed through the humidification filter 72 (that is, the air after humidification) is discharged to the outside of the humidification device 1 through the discharge port 83.

では In the example of FIG. 1, one configuration example of the vaporizing humidifier 1 is shown. Note that the humidifier according to one embodiment of the present invention is not limited to a vaporizing humidifier. The humidifier may be a steam humidifier that generates steam by heating water WT. Alternatively, the humidifier may be an ultrasonic humidifier that atomizes and discharges the water WT.

加 Further, the humidifying device according to one embodiment of the present invention includes any electric device having a humidifying function (eg, home electric appliance). For example, the humidifying device includes an air purifier or an air conditioner having a humidifying function.

As shown in FIG. 2, the distance measuring sensor 10 includes a first control unit 15 (computing device), a light emitting unit 110, and a light receiving unit 120. The humidifying device 1 further includes a fan motor 70 (motor for driving the fan 71) and a second control unit 75. The first control unit 15 controls each unit of the distance measuring sensor 10 as a whole. The first control unit 15 includes a distance calculation unit 150, a water level calculation unit 151, an air volume stage detection unit 152, and a water level correction unit 153. The second control unit 75 controls each unit of the humidifier 1. Note that the first control unit 15 and the second control unit 75 can be provided as an integrated control unit. For example, the function of the first control unit 15 may be integrated with the second control unit 75. Therefore, the second control unit 75 can also function as an arithmetic device.

As an example, the second control unit 75 controls the fan motor 70. By rotating the fan motor 70 at a predetermined rotation speed (rotation speed) (unit: rpm) by the second control unit 75, the fan 71 can be rotated at the same rotation speed. Therefore, the fan 71 can generate a predetermined air volume (a predetermined amount of wind WT) (unit: m ³ / min). Hereinafter, the rotation speed of the fan 71 will be simply referred to as the rotation speed. The air volume (hereinafter, Q) mainly depends on the rotational speed and the mechanical structure of the humidifier 1 (particularly, the structure of a portion that defines the path of the wind WD).

(Outline of processing of distance measuring sensor 10)
The processing of each unit in the distance measuring sensor 10 except for the water level correction unit 153 will be described. The distance measuring sensor 10 optically measures the distance (d in FIG. 1) between the distance measuring sensor 10 (strictly, the light receiving surface of the distance measuring sensor 10) and the water surface of the water WT (hereinafter simply referred to as the water surface). To be detected. The light emitting unit 110 emits the detection light L1 (eg, infrared light) to a predetermined position on the water surface. As an example, the light emitting unit 110 is an LED (Light Emitting Diode). The reflected light L2 in FIG. 1 is light obtained by reflecting the detection light L1 at the predetermined position. The light receiving unit 120 receives the reflected light L2. As an example, the light receiving unit 120 is a photoelectric conversion element (light receiving element) that can detect the reflected light L2 (eg, infrared light). Note that, in FIG. 1, for convenience, the detection light L1 and the reflected light L2 are illustrated so as not to overlap.

The distance calculation unit 150 calculates d based on the detection light L1 and the reflected light L2. Any method may be used as a method for calculating d in distance calculating section 150. As an example, the distance calculation unit 150 calculates d by comparing the phase difference between the detection light L1 emitted by the light emitting unit 110 and the reflected light L2 received by the light receiving unit 120.

The water level calculation unit 151 calculates (detects) the water level (WL) of the water WT in the water storage tray 90 based on d. The water level of the water WT in the water storage tray 90 is, specifically, the height of the water surface of the water WT with reference to the bottom surface in the housing 80. In this specification, the true value of the water level of the water WT is referred to as a true water level value. On the other hand, the water level of the water WT in the water storage tray 90 calculated by the water level calculation unit 151 is also referred to as a water level detection value. In the following description, WL is a water level detection value unless otherwise specified. As an example, the water level calculation unit 151
WL = Hd (1)
Is calculated as WL. The value of H is preset in the water level calculator 151. As described above, the distance measurement sensor 10 can also calculate WL based on the detection light L1 and the reflected light L2.

Furthermore, the water level calculation section 151 calculates a water level level (hereinafter, WLEVEL). The water level is an amount expressed in units of% of WL. For example, a state in which the water WT is not contained in the water storage tray 90 (that is, a state of WL = 0) is set to 0%. On the other hand, a state where the inside of the water storage tray 90 is full (a state where the water level WL has reached a predetermined water level WL0) is set to a water level level of 100%. In this case, the water level calculation unit 151 calculates the water level by setting WLEVEL = (WL / WL0) × 100. As an example, the water level calculator 151 calculates WLEVEL as an integer value.

Further, the water level calculation unit 151 detects (determines) a water level stage. The water level stage is an index indicating the level of WLEVEL. As an example, the water level calculation unit 151
・ Water level stage 0: Water level level 0-4%;
・ Water level 1: Water level 5-14%;
-Water level stage 2: Water level 15-24%;
-Water level stage 3: Water level 25-34%;
-Water level stage 4: Water level 35-44%;
・ Water level 5: Water level 45-54%;
・ Water level stage 6: Water level 55-64%;
-Water level stage 7: Water level 65-74%;
-Water level stage 8: Water level 75-84%;
・ Water level 9: Water level 85-94%;
・ Water level stage 10: Water level 95-104%;
・ Water level 11: Water level 105-114%;
-Water level stage 12: Water level level 115%;
The water level stages are classified into 13 ways (see also FIG. 4 described later). In this specification, “A to B” means “A or more and B or less” unless otherwise specified. Thus, as the number of water level stages increases, the water level increases.

The water level calculation unit 151 can also calculate the amount of water WT (hereinafter, WV) in the water storage tray 90 based on the WL. As an example, the water level calculation unit 151 calculates WV as WV = WL × S. S is the bottom area of the water storage tray 90. The value of S is preset in the water level calculator 151.

The air volume stage detection unit 152 detects (determines) the air volume stage. The air volume stage is an index indicating the size of Q (how large the air volume in the water storage tray 90 is). In this specification, the air volume stage is also referred to as a notch. The notch is set in association with the rotation speed. As an example, the air volume stage detection unit 152 classifies notches into four types of notches 0 to 3 (see also FIG. 4 described later).

A part of the relationship between the number of notches, the number of rotations, and Q in the example of FIG. 4 described below is as follows. For example, in the case of water level stage 0 (example: water level 0%),
Notch 0 (air volume stage 0): 0rpm ^{(rotation-free) (Q = 0m 3 / min} );
Notch 1 (air flow stage 1): 600 rpm (Q = 0.77 m ³ / min);
Notch 2 (air flow stage 2): 950 rpm (Q = 0.96 m ³ / min);
・ Notch 3 (air flow stage 3): 1370 rpm (Q = 1.76 m ³ / min);
It is.

In addition, in the case of the water level stage 10 (example: water level 100%),
Notch 0 (air volume stage 0): 0rpm ^{(rotation-free) (Q = 0m 3 / min} );
・ Notch 1 (air flow stage 1): 650 rpm (Q = 0.84 m ³ / min);
・ Notch 2 (air flow stage 2): 1050 rpm (Q = 1.09 m ³ / min);
・ Notch 3 (air flow stage 3): 1400 rpm (Q = 1.80 m ³ / min);
It is.

As an example, the fan motor 70 may be provided with a sensor (not shown) for detecting the number of rotations. The air volume stage detection unit 152 may acquire the rotation speed from the sensor and determine a notch according to the rotation speed. Alternatively, the air volume stage detection unit 152 may estimate the number of rotations according to the operation state (operation mode) of the humidifier 1. In this case, it is not necessary to provide the fan motor 70 with the sensor.

ＱGenerally, Q tends to increase as the number of rotations increases (see also FIG. 5 described later). In view of this point, as described above, the number of the notch (the number of notches) may be set so as to increase as the rotation speed increases. In this case, Q increases as the number of notches (number of airflow stages) increases. Note that the number of rotations corresponding to the predetermined number of notches may be different depending on the water level stage. Therefore, the Q corresponding to the predetermined number of notches may be different depending on the water level stage. However, in the case of the notch 0, Q = 0 at any water level stage.

(Relationship between Q and measurement accuracy of distance measuring sensor 10)
FIG. 3 is a diagram for explaining a relationship between Q and the measurement accuracy of the distance measurement sensor 10. FIG. 3A shows a case where Q = 0 (that is, a case where the fan 71 is stopped). On the other hand, FIG. 3B shows a case where Q ≠ 0 (that is, a case where the fan 71 is driven). In FIG. 3, some members shown in FIG. 1 are not shown for simplicity.

(3) As shown in FIG. 3A, when Q = 0, the wind WD is not generated, so that the water surface hardly shakes. For this reason, the water surface becomes a substantially flat surface. In this case, unlike the case of FIG. 3B described below, irregular reflection of the detection light L1 does not occur on the water surface. Therefore, the path of the reflected light L2 is substantially constant. In this case, d can be appropriately detected by the distance measuring sensor 10. That is, d is detected as a value sufficiently close to the actual distance between the distance measuring sensor 10 and the water surface (hereinafter, a true distance value). In this case, the WL detected by the distance measuring sensor 10 is a value sufficiently close to the true water level value.

On the other hand, as shown in FIG. 3B, when Q ≠ 0, the water surface shakes due to the influence of the wind WD. For this reason, unlike the case of FIG. 3A, a ripple occurs on the water surface. That is, a local height difference occurs on the water surface. As a result, irregular reflection of the detection light L1 occurs on the water surface, so that the path of the reflected light L2 may change due to irregular reflection.

Therefore, the detection accuracy of d in the distance measurement sensor 10 is reduced. For example, in the case of FIG. 3B, the optical path length of the reflected light L2 incident on the light receiving unit 120 is equal to or larger than the average water level of the case of FIG. It is longer than in the case of FIG. Therefore, the distance measuring sensor 10 detects a distance longer than the true distance value as d. As a result, the WL detection accuracy of the distance measurement sensor 10 also decreases. For example, a WL (water level lower than the true water level) that is different from the true water level is detected by the distance measurement sensor 10.

Furthermore, as Q increases, the sway of the water surface becomes remarkable. For this reason, when Q is large, the detection accuracy of d may be greatly reduced. Thus, the inventor of the present application (hereinafter, the inventor) has newly found a problem that “the measurement accuracy of the distance measurement sensor 10 is reduced due to the fluctuation of the water surface due to the wind WD”. Based on this point, the inventor has come up with a new concept of “preventing a decrease in the measurement accuracy of the distance measurement sensor 10 by considering the influence of the wind WD”. On the other hand, in the related art (eg, Patent Document 1), the above problem is not considered at all. Therefore, the related art does not teach any specific configuration for solving the problem.

Ｑ In addition, Q may be changed according to the water level in the water storage tray 90. For example, when WL is small, Q is set to be large in order to more effectively humidify the air by the humidification filter 72 than when WL is large. Based on this point, the inventor has conceived a further concept of "it is preferable to consider WL in order to prevent a decrease in the measurement accuracy of the distance measurement sensor 10".

(Water level correction unit 153)
The inventor has conceived a concept of “providing a water level correction unit 153 in the distance measurement sensor 10” in order to solve the above problem. The water level correction unit 153 corrects the WL according to the notch (air volume stage) and the water level stage. In other words, the water level correction unit 153 corrects the WL according to (i) the air volume (Q) in the water storage tray 90 and (ii) the water level (in other words, WL) in the water storage tray 90. However, the water level correction unit 153 may correct the WL according to only the notch (only according to Q).

Hereinafter, the corrected WL is referred to as WLS. WLS may be referred to as a corrected water level detection value. As an example, the water level correction unit 153
WLS = WL-PSHIFT (2)
Is calculated as WLS. That is, the water level correction unit 153 subtracts (shifts) the value of WL by PSHIFT. PSHIFT is also called a shift value (shift amount). WL, WLS, and PSHIFT are all arbitrary units. As an example, the units for WL, WLS, and PSHIFT may be mm.

As an example, the water level correction unit 153 sets PSHIFT with reference to the shift value setting table. The shift value setting table is a table in which PSHIFT values corresponding to each notch and each water level stage are set in advance. FIG. 4 is a diagram illustrating an example of the shift value setting table. Hereinafter, a case where the shift value setting table of FIG. 4 is used will be exemplified. However, as the setting method of PSHIFT by the water level correction unit 153, another method may be applied.

考える As an example, consider the case of “notch 1, water level stage 3”. In this case, the water level correction unit 153 sets PSHIFT = 6 with reference to the shift value setting table of FIG. Then, the water level correction unit 153 sets WLS = WL−6. That is, the water level correction unit 153 calculates WLS as a value smaller by 6 than WL. That is, the water level correction unit 153 corrects the WL to a lower water level by 6 (eg, 6 mm).

(4) As shown in FIG. 4, in the case of the notch 0, PSHIFT = 0 is set at any of the water level stages. As described above, when Q = 0, the water surface does not shake due to the wind WD. Thus, when Q = 0, WL need not be corrected.

Also, at each water level stage, the PSHIFT is set to increase as the number of notches increases (more precisely, PSHIFT increases monotonically in a broad sense). That is, as Q increases, WLS is calculated as a smaller value (WL is corrected to a smaller value). As described above, when Q is large, the sway of the water surface can be remarkable. Therefore, in order to effectively cancel the influence of the water surface sway according to Q, it is preferable to increase PSHIFT as Q increases.

The water level correction unit 153 may supply the WLS to the second control unit 75 as the water level detection result. In this case, the second control unit 75 may selectively notify the user of a predetermined notification mode based on the WLS. For example, when WLS is smaller than a predetermined threshold value (hereinafter, a notification threshold value), the second control unit 75 may notify the user to prompt the user to supply water to the water storage tray 90. For example, the second control unit 75 operates a notifying unit (not shown) provided in the humidifying device 1 to cause the user to notify. As an example, the notification unit includes at least one of a lamp, an alarm, and a display panel. By performing the notification based on the WLS instead of the WL, the notification based on the erroneous determination can be avoided, so that the convenience for the user can be improved.

The water level correction unit 153 may detect the corrected water level and the water level stage based on the WLS. Further, the water level correction unit 153 may calculate the corrected water amount based on the WLS.

(effect)
In the distance measurement sensor 10, the water level correction unit 153 can correct WL in consideration of Q. That is, even when the water surface sways due to the wind WD (when WL can deviate from the true water level), the WL can be corrected. Therefore, a corrected value (ie, WLS) closer to the true water level value can be output as a detection result. Thus, according to the distance measuring sensor 10, the water level can be detected more accurately (accurately) than before.

By the way, as described above, Q can change according to the water level in the water storage tray 90. Based on this point, the water level correction unit 153 can further correct the WL in accordance with the WL (one of the detected water level before correction and one of the numerical values related to the true water level). For this reason, it becomes possible to further improve the detection accuracy of the water level.

(Supplementary information)
FIG. 5 is a diagram for explaining one study result by the inventor. Specifically, FIG. 5A shows a graph illustrating an example of the relationship between the air volume and the shift value (shift amount). It can be said that the shift value is an example of an index indicating the degree of water surface sway. FIG. 5B shows a graph illustrating an example of the relationship between the rotation speed and the air flow at each water level (more specifically, at each water level). Each graph in FIG. 5 is a conceptual diagram for explaining an example of a trend. Therefore, no unit is described in each graph.

基づき Based on the graph of FIG. 5A, the inventor confirmed the tendency that “the shift value depends on the air volume”. Further, the inventor has stated that, in the case of a low water level, the water amount (WV) of the water WT in the water storage tray 90 is small. It can be smaller. "

Subsequently, based on the graph of FIG. 5B, the inventor confirmed the tendency that “the larger the rotation speed, the larger the air volume.” Furthermore, the inventor has confirmed the tendency that "the lower the water level, the greater the air volume." As described above, the setting method of the PSHIFT is arbitrary, but it is considered that it is preferable to set the PSHIFT (for example, a water level correction table is created) based on such a tendency.

[Embodiment 2]
The humidifier 1 may be provided with an air volume sensor for measuring Q. The air volume sensor may be provided at a predetermined position in the housing 80. In this case, the water level correction unit 153 may correct the WL according to the Q measured by the air volume sensor. When the humidifier 1 is provided with an air flow sensor, the air flow stage detection unit 152 can be omitted from the first control unit 15.

[Embodiment 3]
When the humidifier 1 is operated, the water level decreases with time. Therefore, as described above, when the water level becomes low, it is preferable to notify the user to urge water supply. From the viewpoint of reducing the user's labor for supplying water to the maximum, it is ideally desirable to notify the user when the water level reaches 0%. However, it is not realistic to set the notification threshold to a value corresponding to the water level 0% in consideration of the variation in the accuracy of the distance measurement sensor 10.

For example, when the distance measurement sensor 10 has detected the WL to be relatively large (that is, to have detected d to be small), a state in which the water WT has actually disappeared from the water storage tray 90 (when the water level is actually 0). %), A water level higher than 0% (eg, a water level of 5%) is detected. Therefore, the user cannot be properly notified.

In view of this point, in the humidifier 1, the notification threshold is generally set to a value slightly larger than the value corresponding to the water level 0%. For example, the notification threshold is set to a value corresponding to a water level of 10%. However, when the notification threshold value is set as described above, the notification that prompts the user to supply water is performed even though the water WT remains in the water storage tray 90 to some extent. As a result, it is not possible to sufficiently reduce the user's labor for supplying water. Based on this point, the inventor further studied conditions for notifying the user.

(One study by the inventor)
FIG. 6 is a diagram for explaining the result of the study by the inventor. In the following description, a state where the water WT is not contained in the water storage tray 90 is referred to as a “waterless state”. In addition, a state in which the water WT is contained in the water storage tray 90 is referred to as a “water presence state”. The graph of FIG. 6A illustrates an example of a temporal change in the detection result of the distance measuring sensor 10 when the state of the water storage tray 90 changes from a state without water to a state with water. In the graph, the horizontal axis represents time (unit: seconds) (hereinafter, t), and the vertical axis represents the average value (hereinafter, dm) of d detected by each of the plurality of distance measurement sensors 10. The distance measurement sensor 10 is also called a tof sensor (time of flight) sensor. For this reason, dm may be referred to as a tof average value.

グラフ In the graph of (a) of FIG. 6, dm has changed remarkably (more specifically, decreased) immediately before t = 100. That is, at this point, the state of the water storage tray 90 has changed from the waterless state to the water-present state. FIG. 6B is an enlarged graph of the portion D1 of FIG. 6A. The graph of FIG. 6B shows an example of the time change of dm in the waterless state. On the other hand, FIG. 6C is an enlarged graph of the portion D2 of FIG. The graph of (c) of FIG. 6 shows an example of a state of a temporal change of dm in the state with water.

In the absence of water, the distance measuring sensor 10 detects the distance between the distance measuring sensor 10 and the bottom surface of the water storage tray 90 as d. Since the bottom surface of the water storage tray 90 is solid unlike the water WT, it has relatively high rigidity. Therefore, even when the humidifier 1 is operating (even when Q ≠ 0), the shape of the bottom surface of the water storage tray 90 does not change due to the influence of the wind WD. Therefore, the actual distance between the distance measuring sensor 10 and the bottom surface of the water storage tray 90 does not change. Therefore, as shown in FIG. 6B, the change (variation) of dm with time is relatively small in the absence of water.

On the other hand, in the presence of water, when Q ≠ 0 as described above, the water surface sways due to the effect of the wind WD. That is, when Q ≠ 0, the shape of the water surface changes variously. That is, the actual distance between the distance measuring sensor 10 and the water surface changes. For this reason, as shown in FIG. 6C, the change in dm with the time change is greater in the state with water than in the state without water.

(Determination processing in Embodiment 3)
First, the second control unit 75 determines that the water level has reached the notification threshold (a value corresponding to a water level of 10%). Then, the second control unit 75 continues the operation of the humidifier 1 for a predetermined operation allowable time (eg, one hour) from the time when the determination is made.

Next, the second control unit 75 calculates a parameter indicating the magnitude of the change (fluctuation) of d at every predetermined time period (for example, 30 seconds). As an example, the second control unit 75 calculates Δ = dmax−dmin. dmax is the maximum value of d in the time period, and dmin is the minimum value of d in the time period. Δ is one of the indices (parameters) indicating the magnitude of the change of d in the time period.

Next, the second control unit 75 performs a magnitude comparison between Δ and a predetermined threshold (hereinafter, dth). dth is also called a fluctuation threshold. Specifically, the second control unit 75 determines whether Δ ≦ dth. The value of dth may be set by the designer of the humidifier 1 based on the experimental results obtained in advance (eg, the graphs of FIGS. 6B and 6C). As an example, dth = 1 may be set.

When Δ ≦ dth (for example, in the case of the example of FIG. 6B), it can be said that the fluctuation of d is relatively small. That is, it is expected that the distance between the distance measuring sensor 10 and the bottom surface of the water storage tray 90 is detected as d. Therefore, when Δ ≦ dth, the second control unit 75 may detect a waterless state (may determine that the water storage tray 90 is in the waterless state). When detecting the absence of water, the second control unit 75 notifies the user to prompt for water supply. When detecting the absence of water, the second control unit 75 may stop the operation of the humidifier 1 even before the allowable operation time has expired.

On the other hand, when Δ> dth (for example, in the example of FIG. 6C), it can be said that the fluctuation of d is not so small. For this reason, when Δ> dth, the second control unit 75 may detect the presence of water (may determine that the water storage tray 90 is in the presence of water). When detecting the water presence state, the second control unit 75 does not notify the user.

As described above, the second control unit 75 may determine whether or not to notify the user based on the notification threshold and the variation threshold. By introducing the fluctuation threshold value, the waterless state can be determined with higher accuracy than when only the notification threshold value is used. As a result, it is possible to effectively reduce the user's labor for supplying water while taking into account variations in the accuracy of the distance measurement sensor 10.

[Example of software implementation]
The control blocks (especially the first control unit 15 and the second control unit 75) of the humidifier 1 may be realized by a logic circuit (hardware) formed on an integrated circuit (IC chip) or the like, or may be realized by software. May be.

In the latter case, the humidifying device 1 includes a computer that executes instructions of a program that is software for realizing each function. This computer includes, for example, at least one processor (control device) and at least one computer-readable recording medium storing the program. Then, in the computer, the object of one embodiment of the present invention is achieved when the processor reads the program from the recording medium and executes the program. As the processor, for example, a CPU (Central Processing Unit) can be used. Examples of the recording medium include “temporary tangible media” such as ROM (Read Only Memory), tapes, disks, cards, semiconductor memories, and programmable logic circuits. Further, a RAM (Random Access Memory) for expanding the program may be further provided. Further, the program may be supplied to the computer via an arbitrary transmission medium (a communication network, a broadcast wave, or the like) capable of transmitting the program. Note that one embodiment of the present invention can also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

[Summary]
The water level detection device according to aspect 1 of the present invention is a water level detection device that detects a water level in a container, and a light emitting unit that emits detection light to a predetermined position on a water surface in the container, wherein the detection light is A light receiving unit that receives reflected light that is light reflected at a predetermined position; and a computing device, wherein the computing device is configured to detect a water level that is a detection value of the water level based on the detection light and the reflected light. A detection value is calculated, and the water level detection value is corrected according to the air volume in the container.

According to the above configuration, unlike the conventional water level detection device, the water level detection value is corrected in consideration of the air volume in the container (that is, in consideration of the influence of the water surface sway caused by the wind in the container). it can. Therefore, the water level can be detected more accurately than before.

では In the water level detection device according to the second aspect of the present invention, in the first aspect, it is preferable that the arithmetic unit further corrects the water level detection value according to the water level detection value before correction.

の通り As described above, the air volume in the container can change according to the water level in the container. Therefore, according to the above configuration, the water level detection value can be corrected by further considering the water level in the container. For this reason, the detection accuracy of the water level can be further improved.

In the water level detection device according to the third aspect of the present invention, in the first or second aspect, it is preferable that the arithmetic unit corrects the water level detection value to a smaller value as the air volume increases.

According to the above configuration, the water level detection value can be corrected so as to cancel the influence of the water surface sway corresponding to the increase in the air volume. For this reason, the detection accuracy of the water level can be further improved.

A humidifying device according to a fourth aspect of the present invention includes the water level detection device according to any one of the first to third aspects, and the container that receives water, wherein the water level detection device detects the water level. Is preferred.

[Appendix]
One aspect of the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and the technical means disclosed in the different embodiments may be appropriately combined. Also about the obtained embodiment. It is included in the technical scope of one embodiment of the present invention. Further, new technical features can be formed by combining the technical means disclosed in each embodiment.

1 Humidifier 10 Distance measuring sensor (water level detector)
15 First control unit (arithmetic unit)
75 Second control unit (arithmetic unit)
90 water storage tray (container)
110 Light emitting unit 120 Light receiving unit 150 Distance calculating unit 151 Water level calculating unit 152 Air volume stage detecting unit 153 Water level correcting unit L1 Detected light L2 Reflected light WD Wind WT Water WL Water level

Claims

A water level detection device for detecting a water level in the container,
A light emitting unit that emits detection light to a predetermined position on the water surface in the container,
A light-receiving unit that receives reflected light, which is light that is the detection light reflected at the predetermined position;
And an arithmetic unit,
The arithmetic unit is
Based on the detection light and the reflected light, calculate a water level detection value that is a detection value of the water level,
A water level detection device that corrects the water level detection value according to an air volume in the container.
The water level detection device according to claim 1, wherein the arithmetic unit further corrects the water level detection value according to the water level detection value before correction.
The water level detection device according to claim 1 or 2, wherein the arithmetic unit corrects the water level detection value to a smaller value as the air volume increases.
A water level detection device according to any one of claims 1 to 3,
And a container for receiving water,
A humidifier, wherein the water level detecting device detects the water level.