TWI486585B - Capacitive moisture detection device - Google Patents

Description

Capacitive moisture detecting device Field of invention

The present invention relates to a capacitive moisture detecting device for detecting a change in a ratio or state of moisture of a surrounding environment to output a detection signal. The moisture detecting device of the present invention can detect a sprinkling sensor or a liquid level sensor that is required to be sprinkled by using a frosting sensor that detects a frosting state of the cooler and a dry state corresponding to the soil.

Background of the invention

Conventionally, in a refrigerating and freezing apparatus such as a refrigerator or a freezer, there is a problem that moisture is cooled and adhered to a cooler, and various defrosting methods have been proposed to solve this problem.

For example, using a timer, the heater is driven after an appropriate time interval to heat the cooler or the like for defrosting. However, in this case, there is a problem that defrosting is actually performed, and there is excessive driving to waste power.

Therefore, it has been proposed to detect whether the cooler has frost by means of an inductor, and to start the heater to defrost when there is frost.

For example, it has been proposed to provide an electrical boundary sensor composed of a metal bar and facing a cooler to detect a change in capacitance caused by frosting (Patent Document 1). Patent Document 1 describes that an alternating current signal is applied to an electrical boundary sensor to emit Radio waves. If there is frost within the range of the transmitted wave of the electrical sensor, the capacitance will change, so the frosting state can be detected by detecting the change in capacitance.

[First technical literature] [Patent Literature]

[Patent Document 1] Japanese Invention Patent Publication No. 2010-91171

Summary of invention

However, under the detection method disclosed in Patent Document 1, the electric wave emitted by the electric boundary sensor will reach a wide area including the peripheral open space, and its radio wave emission range is wide. Therefore, various factors affect the detection accuracy, and it is difficult to improve the detection accuracy.

On the other hand, in the detection method of Patent Document 1, a dummy electrode is provided in the same environment as the electrode of the electric boundary sensor, and the output change of the electric boundary sensor is corrected by the output of the camouflage electrode. Therefore, it is necessary to disguise the electrode and its control circuit, and there is a problem that the overall configuration is complicated.

In view of the above problems, the present invention has an object of providing a capacitive moisture detecting device which is capable of detecting a frosting state with sufficient accuracy without providing a dummy electrode.

An apparatus according to an embodiment of the present invention is a capacitive moisture detecting device that detects a change in capacitance in response to a change in a ratio of a moisture content of a surrounding environment or a state, and includes: a capacitive sensor having a mutual orientation Configuring the first electrode and the second electrode, and the capacitance is in accordance with the foregoing The ratio of the water content or the state between the first electrode and the second electrode is changed; the driving unit is an alternating current signal to the capacitance sensor; and the determining unit is based on the magnitude of the output voltage from the capacitance sensor. Binary and output the detection signal that is turned on or off.

The capacitance sensor may be connected between an output of the driving unit and an input of the determining unit, or may be connected between an output of the driving unit and a ground line.

The determining unit may perform the binarization by comparing an output voltage from the capacitance sensor with a predetermined threshold.

According to the present invention, it is possible to provide a capacitive moisture detecting device which is capable of detecting a frosting state with sufficient accuracy without providing a dummy electrode and having a simple structure.

1, 1B, 1D‧‧‧ frost condition detection device (capacitive moisture detection device)

11, 11B, 11C, 11D‧‧‧ drive department

12, 12B, 12C, 12D‧‧‧Decision Department

13‧‧‧Frost sensor (capacitive sensor)

13C, 13D‧‧‧ moisture sensor (capacitive sensor)

1C‧‧‧Detection device (capacitive moisture detection device)

21, 21C, 21D‧‧‧ substrates

22, 22C‧‧‧1st pattern electrode (1st electrode)

22Da, b‧‧‧ first electrode

23, 23C‧‧‧2nd graphic electrode (2nd electrode)

23D‧‧‧2nd electrode

31, 32‧‧‧electrode rod (first electrode, second electrode)

31B, 32B‧‧‧ wires (first electrode, second electrode)

31C, 32C‧‧‧ wires (first electrode, second electrode)

32, 30B, 30C‧‧‧ moisture sensor (capacitive sensor)

C1‧‧‧ capacitor

C2‧‧‧ capacitor (capacitor parts)

C3‧‧‧ capacitor (second capacitor part)

Cs‧‧‧ capacitor

D2‧‧‧ diode

GS‧‧‧Signal Generation Department

HA‧‧‧ comb teeth

IF, IF B‧‧‧ input face

KD, KDB, KDC, KDD‧‧‧Dualization Department

RKP‧‧‧ Cooling tube

Q3‧‧‧NOT circuit (1st NOT circuit)

Q4‧‧‧NOT circuit (2nd NOT circuit)

Q6‧‧‧NOT circuit (correction department)

R1‧‧‧Resistors

R10‧‧‧resistance (feedback resistor)

R2‧‧‧Resistors (resistance parts)

R3‧‧‧resistance (second resistance part)

RK‧‧‧Freezer

RP‧‧‧cooler

Rs‧‧‧ resistance value

S1‧‧‧ output voltage

S1a‧‧‧ exchange signal

S1b‧‧‧ output voltage

S1c‧‧‧ output voltage

S2, S2a, S2b‧‧‧ detection signals

SYD‧‧‧Amendment

Th‧‧‧ threshold

Thr1, th1a, th1b‧‧‧ threshold (first threshold)

Th2‧‧‧ threshold (second threshold)

Zs‧‧‧ resistance

Fig. 1 is a view showing the configuration of a frosting state detecting device according to the first embodiment. Figure.

Fig. 2 is a front elevational view showing the appearance of the frost sensor used in the first embodiment.

Fig. 3 is a view showing an example of a specific circuit of the frosting state detecting device.

Fig. 4 is a view showing an example of a circuit of the frosting state detecting device of the second embodiment.

Fig. 5 (A) to (C) show a capacitance type detecting device of a third embodiment A diagram of the appearance.

Fig. 6 is a view showing an example of a circuit of a capacitance detecting device according to a third embodiment.

Fig. 7 is a view showing an example of a moisture sensor for detecting surface moisture.

Fig. 8 is a view showing an example of the arrangement when the capacitance type detecting device is used as a liquid level sensor.

Fig. 9 (A) and (B) are views showing other examples of the moisture sensor.

Fig. 10 is a view showing the configuration of the frosting state detecting device of the fourth embodiment.

Fig. 11 is a front elevational view showing the appearance of the frost sensor used in the fourth embodiment.

Fig. 12 is a view showing, in an enlarged manner, a part of the frost sensor and the cooling pipe of the fourth embodiment.

Fig. 13 is a view showing an example of a specific circuit of the frosting state detecting device of the fourth embodiment.

Fig. 14 is a view showing an example of a circuit for realizing a NOT circuit.

Fig. 15 (A) to (C) are diagrams showing examples of waveforms of respective portions of the frosting state detecting device.

Fig. 16 (A) to (C) show the state in which the frosting state is detected.

Fig. 17 is a view showing the operation state of the correction unit.

Fig. 18 is a view showing an example of the relationship between the state of moisture and the operating state of the refrigerator.

Fig. 19 is a view for explaining changes in the operating state of the refrigerator.

Detailed description of the preferred embodiment [First Embodiment]

First, a first embodiment in which the capacitive moisture detecting device of the present invention is implemented as a frosting state detecting device will be described.

In the first drawing, the frosting state detecting device 1 is composed of a driving unit 11, a determining unit 12, a frost sensor 13, and the like. Fig. 2 shows the appearance of the frost sensor 13.

In the first and second figures, the drive unit 11 is a circuit that applies an alternating current signal to the frost sensor 13. The sine wave, rectangular wave, triangular wave, etc. are used for the alternating signal. The frequency of the alternating signal to use the frequency of the long or medium band. For example, a frequency of about 50 kHz to 1 MHz, or for example, 57 kHz, 400 kHz, or the like, or other frequencies can be used.

The determination unit 12 performs binarization in accordance with the magnitude of the output voltage S1 of the frost sensor 13, and outputs a detection signal S2 indicating whether or not the frosting state is present.

That is, the determination section 12 is based on frosting due to the cooler RP When the resistance value between the first pattern electrode 22 and the second pattern electrode 23 of the frosting sensor 13 described later increases and the output voltage S1 of the alternating current signal generated by the capacitance decrease is larger than the threshold value, the output is displayed as a frosting state. The detection signal S2.

The frosting sensor 13 has a first pattern electrode 22 and a second pattern electrode 23 which form a pattern facing each other on the surface of the substrate 21. The frosting sensor 13 is mounted on the surface of the cooler RP.

The substrate 21 is a plate made of glass epoxy resin, ceramics or the like. Formed on the surface of the substrate 21 side by a metal material such as copper The first pattern electrode 22 and the second pattern electrode 23 are formed. Further, as the substrate 21, a flexible substrate (FPC) having a pattern formed of a copper foil or the like on the surface of the film-like insulator may be used.

As shown in Fig. 2, the first pattern electrode 22 and the second pattern electrode 23 are comb-like, and are formed in a pattern in which the respective comb teeth HA face each other.

In the embodiment shown in Fig. 2, each of the first pattern electrode 22 and the second pattern electrode 23 has three comb teeth HA, and one of the comb teeth HA has a state in which the other comb tooth HA enters. Thereby, a gap GP is formed between the comb teeth HA of the first pattern electrode 22 and the comb teeth HA of the second pattern electrode 23.

The size of the frosting sensor 13 can be exemplified as follows. The substrate 21 may be, for example, a rectangle having a side of several millimeters or a few centimeters. For example, about 1 cm in length and about 2 cm in width. It may also be a non-rectangular circle, an ellipse, a polygon, or the like. The gap GP between the comb teeth HA of the first pattern electrode 22 and the comb teeth HA of the second pattern electrode 23 is, for example, several tens of micrometers (μm) or several hundreds of micrometers.

In the frosting sensor 13, the initial value of the resistance value Rs between the first pattern electrode 22 and the second pattern electrode 23 is several tens of megameters or more, but if water droplets are attached, it is reduced by several tens of k Ω. If the attached water droplets freeze into ice or frost, it will rise by several hundred k Ω.

Further, the initial value of the capacitance Cs between the first pattern electrode 22 and the second pattern electrode 23 is ten pF or several tens of pF, and if water droplets are attached, it is increased by about 80 times. If the attached water droplet freezes into ice or frost, the capacitance Cs will decrease to about 1/20 of that when it is water.

Thus, in the frosting sensor 13, the resistance value Rs and the capacitance Cs may be due to the occasion where the surface has water droplets attached thereto and the case where the water droplets are not attached, and the water droplets are frozen. And drastic changes. Since the resistance value Rs increases while the water droplet freezes and the capacitance Cs decreases, the resistance Zs (=Rs+1/j ω Cs) for the alternating current signal is greatly increased.

Further, a plurality of types of the comb teeth HA, the shape, the length, and the size of the gap GP between the comb teeth HA can be selected. When the number and length of the comb teeth HA are increased, the resistance value Rs is lowered and the capacitance Cs is increased. When the gap GP between the comb teeth HA is reduced, the resistance value Rs is lowered and the capacitance Cs is increased.

In the present embodiment, the presence or absence of the frosting state is detected by the change in the resistance Zs of the frosting sensor 13 caused by the freezing of the water droplets.

As shown in Fig. 1, the frosting sensor 13 is mounted in a state of being close to or in contact with the cooler RP. For example, it can be screwed to the cooler RP directly or through a spacer using a screw or the like. Alternatively, a cooling pipe directly attached to the cooler RP using an adhesive or the like is used. Alternatively, the double sided tape is applied to the surface of the cooler RP.

Thereby, the state of the atmosphere between the first pattern electrode 22 and the second pattern electrode 23 in the frosting sensor 13 and the state of the moisture contained in the atmosphere are changed in accordance with the frosting state or the frozen state of the cooler RP, and the resistance is changed. Zs will change accordingly.

Further, since the frosting sensor 13 is mounted close to the cooler RP, it will be installed in an atmospheric environment. In other words, in the present embodiment, the frost sensor 13 detects whether or not the moisture in the atmosphere due to the cooling effect of the cooler RP freezes and changes to a frost shape, instead of whether the water contained in a specific container or the like is water. freeze.

Therefore, the frosting sensor 13 can be installed with its surface temperature close to the surface temperature of the cooler RP. By letting the temperature of the frosting sensor 13 and the cooler RP When the surface temperature is the same, the water vapor in the atmosphere near the cooler RP can be made to adhere to the gap GP of the frost sensor 13 when the water droplets fall, and if the temperature falls below the freezing point, the water droplets will freeze to a frosty shape.

Next, a specific circuit example of the drive unit 11 and the determination unit 12 will be described.

In Fig. 3, the drive unit 11 is composed of NOT circuits Q1 and Q2, resistors R1 and R2, and a capacitor C1. The signal generating unit GS that generates the alternating current signal is configured by the NOT circuits Q1 and Q2, the resistor R1, and the capacitor C1. Further, the state of the resistor R2 is connected in series to the output side of the signal generating portion GS.

A frequency selective voltage dividing circuit is formed by the resistor R2 and the resistance Zs of the frosting inductor 13. The value of the resistor R2 is set such that the change in the output voltage S1 caused by the frost increases with respect to the frequency of the alternating current signal output from the driving portion 11. Therefore, the resistance value of the resistor R2 is set in accordance with the resistance Zs of the frosting inductor 13. For example, tens of K ω or hundreds of k Ω, for example, about 100k Ω.

The determination unit 12 is composed of a NOT circuit (binary circuit) Q3, NOT circuits Q4 to Q5, resistors R3 to R8, capacitors C2 and C3, a diode D1, a light-emitting diode LEDa, and an LEDb. The input dielectric surface IF is constituted by a resistor R3 and a capacitor C2 which are connected in series to each other. The binarization unit KD is configured by the NOT circuit Q3, the resistors R4 to R6, the capacitor C3, the diode D1, and the like. The binary unit KD is connected to the output side of the input interface IF.

When the magnitude of the input output voltage S1 exceeds the threshold value th, the binary unit KD has a low level (L). When the input output voltage S1 does not exceed the threshold th, its output is maintained at a high level (H). The size of the threshold th is determined by The resistance values of the resistors R4 and R5 are adjusted. In other words, by selecting various resistance values of the resistors R4 and R5, the power supply voltage can be divided into various voltages by the two resistors R4 and R5, and various threshold values th can be set.

Further, the relationship between the magnitude of the output voltage S1 and the output L, H (or on, off) may be reversed.

Further, the display output unit HS is configured by the NOT circuits Q4 and Q5, the resistors R7 and R8, the light-emitting diodes LEDa and b, and the like. When the frosting state is detected, the light-emitting diode LEDa is turned on, and in the non-frosting state, the light-emitting diode LEDb is turned on.

The determination unit 12 outputs a detection signal S2a displayed as a frosting state and a detection signal S2b displayed as a non-fool state.

The determination unit 12 of the frosting state detecting device 1 performs digital processing on the output voltage S1 of the frost sensor 13 to perform binarization.

Further, although the frosting state detecting device 1 is also provided with a power supply circuit or the like, it is omitted in the drawings. It is also possible to supply power from the outside.

On the output side of the drive unit 11, the terminal Ta on the side of the frost sensor 13 is connected to the absolute electric wire DSa. The terminal Tb on the other side of the frosting sensor 13 is connected to the ground line GL in the frosting state detecting device 1 by the absolute electric wire DSb.

Further, in the first drawing, the display drive unit 11, the determination unit 12, and the frost sensor 13 are separated, but they may have an integrated structure. In other words, the drive unit 11 and the determination unit 12 may be combined with the frost sensor 13 as a unit. In this case, for example, the substrate 21 may be a double-sided substrate or a multilayer substrate, and the driving portion 11 and the determining portion 12 may be provided by a surface other than the surface on which the pattern electrode is provided. The electronic components for the driving portion 11 and the determining portion 12 are covered, for example, by a mold. And a connection member for outputting the detection signals S2a, b and connecting the power supply circuit (power supply device).

Next, the operation of the frosting state detecting device 1 will be described.

The resistance Zs of the frosting sensor 13 varies with the frosting state. When the frosting sensor 13 is applied with an alternating current signal by the driving unit 11, the output voltage S1 of the frosting sensor 13 changes in accordance with the resistance Zs of the frosting sensor 13. When the magnitude of the output voltage S1 exceeds the threshold value th, the detection signal S2a indicating the frosting state is output.

In this way, the defrosting heater can be activated according to the detection signal S2a to energize it to perform the defrosting operation. When the defrosting heater is activated and the frost of the cooler RP is dissolved into water droplets, the electric resistance Zs of the frosting sensor 13 is lowered and the output voltage S1 is also lowered. When the magnitude of the output voltage S1 is equal to or less than the threshold value, the detection signal S2b showing the non-frosting state is output.

Thus, the defrosting of the cooler RP can be efficiently performed by controlling the switches of the defrosting heater (not shown) based on the detection signals S2a, S2b.

Further, the threshold value th detected as the frosting state and the threshold value th value detected as the non-fondening state may be the same value or may be different values. If the threshold th is made to be a different value, hysteresis can be detected. Further, regarding the control method of the defrosting heater or the like for defrosting, the above Patent Document 1 and the like can be referred to.

In the frosting sensor 13 of the present embodiment, the first pattern electrode 22 and the second pattern electrode 23 face each other on the substrate 21. Since the space for realizing the resistance Zs is a closed space, it is less susceptible to surrounding objects. Whether or not The influence of environmental factors such as movement, air flow, and ambient temperature can improve the detection accuracy. Therefore, it is not necessary to use a camouflage electrode or the like to correct the output variation caused by environmental changes, and it is possible to operate reliably with a simple configuration.

As described above, the frosting state detecting device 1 of the present embodiment can detect the frosting state with sufficient accuracy without providing a dummy electrode, and the configuration is simple.

[Second Embodiment]

Next, another embodiment of the capacitive moisture detecting device of the present invention, which is a second embodiment of the frosting state detecting device, will be described.

Fig. 4 is a view showing a specific circuit example of the frosting state detecting device 1B of the second embodiment.

The frosting state detecting device 1B in Fig. 4 is composed of a driving unit 11B, a determining unit 12B, a frosting sensor 13, and the like.

In the frosting state detecting device 1B of the second embodiment, the overall configuration and the frost sensor 13 are the same as those of the frosting state detecting device 1 of the first embodiment shown in Figs. 1 and 2 . Further, the drive unit 11B and the frost sensor 13 are the same as the drive unit 11 and the frost sensor 13 shown in FIG. Regarding the same portions, the description thereof will be omitted or simplified.

The determination unit 12B is composed of NOT circuits Q11 to Q14, resistors R11 to R14, capacitors C2 and C11, a diode D2, and a light-emitting diode LEDa.

The binarization unit KDB is configured by the NOT circuits Q11 and Q12, the resistors R11 to R13, the capacitor C11, the diode D2, and the like. Further, the display output unit HSB is configured by the NOT circuits Q13 and Q14, the resistor R14, the light-emitting diode LEDa, and the like. Light-emitting diode LEDa when detected as frosting Will light up. The determination unit 12B outputs a detection signal S2a displayed in a frosting state and a detection signal S2b displayed in a non-fondening state.

The determining unit 12B of the frosting state detecting device 1B performs analogy processing on the output voltage S1 of the frosting sensor 13 to perform binarization.

[Third embodiment]

Next, a third embodiment in which the capacitive moisture detecting device of the present invention is used as a general detecting device to detect moisture will be described.

Fig. 5 and Fig. 6 show specific circuit examples of the detection device 1C and the detection device 1C of the third embodiment, respectively. 5(A), (B), and (C) are a front view, a left side view, and a rear view of the detecting device 1C.

As shown in Fig. 5, the detecting device 1C has a structure in which the entire body is substantially integrated into a rectangular parallelepiped shape.

As shown in Fig. 6, the detecting device 1C is composed of a driving unit 11C, a determining unit 12C, a moisture sensor (capacitance sensor) 13C, and the like. The circuits of the drive unit 11C and the determination unit 12C are the same as those of the drive unit 11 and the determination unit 12 shown in FIG. 3, and therefore, the same reference numerals are given to components having the same functions.

In other words, the detecting device 1C forms the first pattern electrode 22C and the second pattern electrode 23C for the moisture sensor 13C on the surface on one side of the rectangular substrate 21C of the multilayer substrate, and the two terminals Ta and Tb are set to each other. near.

On the other surface of the substrate 21C, electronic components for the driving portion 11C and the determining portion 12C are mounted, and the pattern wiring is welded or the like to form each circuit. The electronic components of the drive unit 11C and the determination unit 12C are covered by the mold MD, and the light-emitting diodes LEDa and b can be seen from the outside in one part of the mold MD. also, The portion of the substrate 21C that is not covered by the mode MD is provided with a connector CN1 for outputting the detection signals S2a, b and connecting the power supply circuit.

The substrate 21C is provided with an output terminal T11 of the driving portion 11C and an input terminal T12 of the determining portion 12C. These terminals T11 and T12 and the terminals Ta and Tb of the moisture sensor 13C are connected to each other inside the mold MD. Thereby, as shown in FIG. 6, the moisture sensor 13C connects the output terminal T11 of the drive unit 11C and the input terminal T12 of the determination unit 12C in series.

Moreover, the two terminals T11 and T12 and the terminal Ta on the moisture sensor 13C side can be connected to each other by the electric wires, and the other terminal Tb of the moisture sensor 13C can be connected to the ground line (ground terminal) GL of the substrate 21C. At this time, the moisture sensor 13C is connected in parallel to the output terminal T11 of the drive unit 11C and the input terminal T12 of the determination unit 12C.

In this manner, the detecting device 1C is in a state before the mold MD covers the substrate 21C, and the selective moisture sensor 13C connects the output terminal T11 of the driving unit 11C and the input terminal T12 of the determining unit 12C in either series or in parallel.

The magnitude of the threshold th for binarization in the determining unit 12C can be adjusted by selecting the resistance values of the resistors R4 and R5. To make it easy to adjust, a variable resistor can be used for either or both of these resistors R4, R5.

Next, the operation of the detecting device 1C will be described.

The resistance Zs (resistance value Rs and capacitance Cs) of the moisture sensor 13C varies depending on the ratio or state of moisture of the surrounding environment. For example, when the detecting device 1C is used for detecting the frosting state, the resistance Zs changes with the frosting state. When it is in the non-frosting state, the resistance Zs of the moisture sensor 13C is low, and the alternating current signal S1a from the driving portion 11C becomes the output voltage S1b with little attenuation, and the input The process proceeds to the determination unit 12C. When the frosting state is reached, the electric resistance Zs of the moisture sensor 13C is increased, and the alternating current signal S1a from the driving unit 11C is greatly reduced to the output voltage S1b, and the input to the determining unit 12C is lowered. The fluctuation of the signal (output voltage S1b) input from the determination unit 12C is detected by the threshold value th, thereby detecting the presence or absence of the frosting state.

That is, when the magnitude of the output voltage S1 is equal to or less than the threshold value th, the detection signal S2a showing the frosting state is output.

As described above, with the detecting device 1C of the present embodiment, it is possible to detect the frosting state with sufficient accuracy without providing a dummy electrode, and the configuration is simple.

[Other Embodiments of Capacitive Moisture Detection Device]

The detecting device 1C described above can operate not only the frosting state but also the capacitive moisture detecting device for detecting the moisture ratio or state of the surrounding environment.

That is, the detecting device 1C can be used for, for example, a sprinkler sensor, a liquid leakage sensor, a freeze sensor, a liquid level sensor, or an ice sensor, by various settings of the threshold value th.

[sprinkling sensor]

When the detecting device 1C is used for the water sprinkling sensor, the detecting device 1C is buried in a field or the like. The moisture sensor 13C contacts the soil, and the resistance Zs (especially the capacitance Cs) of the moisture sensor 13C changes corresponding to the amount of moisture in the soil.

That is, the relative dielectric constant ε of the soil is, for example, about 4 when dry, and about 76, 87, and 94 when the moisture is 1%, 2%, and 5%, respectively, and the relative dielectric constant ε of the soil caused by moisture. It has changed a lot. Therefore, the dry state of the soil can be detected by the detecting device 1C, and when it is in a dry state, for example, The sprinkler can be sprinkled to sprinkle water.

Further, when the detecting device 1C is used as a water sprinkling sensor, the detecting device 1C may not be buried in the ground, and the moisture sensor (capacitor sensor) 30 for use may be buried in the ground.

That is, as shown in Fig. 7, the two electrode rods 31, 32 are inserted into the ground ZM at a proper interval in parallel with each other to partially or completely bury the soil in the soil. Two electrode rods 31 and 32 are used as the moisture sensor 30. The terminals Ta and Tb of the electrode rods 31 and 32 are connected to the terminals T11 and T12 of the detecting device 1C in place of the terminals Ta and Tb of the moisture sensor 13C described above. At this time, the moisture sensors 30 are connected in series.

Further, in a state where the terminals T11 and T12 of the detecting device 1C are connected to each other, the terminals T11 and T12 are connected to one terminal Ta of the moisture sensor 30, and the other terminal Tb of the moisture sensor 30 is connected to the ground line GL. At this time, the moisture sensors 30 are connected in parallel.

At this time, the moisture sensor 30 may be connected to the detecting device 1C through a capacitor (capacitor/c conduction densor) to remove unnecessary DC components in the voltage. That is, at this time, a capacitor is inserted between the terminals Ta and Tb and the terminals T11 and T12 or the ground line GL.

Further, as the electrode rods 31 and 32, a gold dragon material such as copper, an aluminum alloy, or iron may be used, or a rod formed of another conductive material may be used. Further, although it is easy to install the electrode rods 31 and 32 when they are driven into the ground ZM, the electrode rods 31 and 32 may be buried in the soil after the excavation of the ground ZM. At this time, the electrode rods 31, 32 may be in a vertical posture, a horizontal posture, or a dumping posture.

When such a moisture sensor 30 is used, between the electrode rods 31, 32 The capacitance Cs will vary with the amount of moisture in the ground ZM. By detecting the change in the capacitance Cs by the threshold value th, the dry state of the soil can be detected.

[water leakage sensor]

When the detecting device 1C is used as the water leakage sensor, the detecting device 1C is attached to the floor or the like of a building. When there is no water leakage, the periphery of the moisture sensor 13C is empty or ground material (for example, plastic), so the relative dielectric constant ε is small, and the capacitance Cs is, for example, about 0.1 pF. When the moisture sensor 13C is wetted by water due to water leakage, the relative dielectric constant ε is about 80, and the capacitance Cs is increased by, for example, a few pF. Therefore, the change can be detected by the threshold value th.

[freeze sensor]

When the detecting device 1C is used as the freezing sensor, the detecting device 1C is placed on a road surface such as an expressway. That is, the surface of the moisture sensor 13C configured as the detecting device 1C is in the same state as the road surface. When the surface of the moisture sensor 13C freezes, the capacitance Cs is thus reduced by about 1/20, so that the threshold value th can be detected. It can also be detected when the surface freezes into a slush.

[liquid level sensor]

When the detecting device 1C is used, as shown in Fig. 8, the detecting device 1C is attached to the outer peripheral surface of the plastic container YK1 or the like in which the liquid LQ is accommodated. Since the thickness of the container YK1 is thin enough, when the liquid level HM in the container YK1 reaches the position of the detecting device 1C, the capacitance Cs changes to be large, and the threshold value th can be detected to detect the change.

Further, when the detecting device 1C is used as the liquid level sensor, as shown in Fig. 9, a moisture sensor for use (capacitive sensing) can also be used. Instead of the moisture sensor 13C, 30B, 30C.

In other words, as shown in Fig. 9(A), the two electric wires 31B and 32B are wound around the outer circumferential surface of the container YK2 at a proper interval in parallel with each other, thereby serving as the moisture sensor 30B. . The terminals Ta and Tb of the electric wires 31B and 32B are respectively connected to the terminals T11 and T12 of the detecting device 1C or the ground line GL. The electric wires 31B, 32B may be single wires or stranded wires, and the cross section may be a circular shape or a flat plate shape (ie, a belt shape). The electric wires 31B, 32B are preferably insulated wires.

When the liquid level HM in the container YK2 reaches the position of the moisture sensor 30B, the capacitance Cs changes to be large, and this change can be detected.

Further, as shown in Fig. 9(B), the two electric wires 31C and 32C are placed on the outer peripheral surface of the container YK3 so as to be opposed to each other with the liquid LQ accommodated in the inside of the container, and the container is wound halfway. The outer peripheral surface is used as the moisture sensor 30C. When the liquid level HM in the container YK3 reaches the position of the moisture sensor 30C, the capacitance Cs changes to be large, and this change can be detected.

Further, when the detecting device 1C is applied to these various sensors, it is also possible to detect that the respective environmental states have changed when the relative dielectric constant ε or the amount of change in the capacitance Cs approaches zero. That is to say, when the relative dielectric constant ε or the capacitance Cs changes and the amount of change is small enough, it is determined that there is an environmental state. For example, it is determined that it is in a dry state, or it is determined that the ice making is completed, or has been frozen, or it is determined that the liquid level has reached the predetermined position.

[Fourth embodiment]

Next, a fourth embodiment in which the capacitive moisture detecting device of the present invention is used as a frosting state detecting device of another embodiment will be described.

Fig. 10 is a view showing the frosting state detecting device of the fourth embodiment; In the configuration of 1D, Fig. 11 shows the appearance of the frost sensor 13D for the frosting state detecting device 1D, and Fig. 12 shows an enlarged portion of Fig. 10. Further, Fig. 13 shows an example of a specific circuit of the frosting state detecting device 1D, and Fig. 14 shows an example of a circuit for realizing the NOT circuit. Further, Fig. 15 shows an example of the waveform of each part of the frosting state detecting device 1D.

In the figure 10, the frosting state detecting device 1D is covered with a mold except for the surface of the moisture sensor 13D, and its structure is integrated into a substantially rectangular shape.

The frosting state detecting device 1D is attached to a cooling pipe RKP provided in the refrigerator RK by a belt (not shown) or a heat shrinkable tube. The frosting state detecting device 1D is connected to the control unit RKC of the refrigerator RK by electric wires, thereby receiving the power supply from the control unit RKC or outputting the detection signal S2a for control to the control input terminal TS of the control unit RKC.

As shown in Fig. 13, the frosting state detecting device 1D is composed of a driving unit 11D, a determining unit 12D, a moisture sensor (capacitance sensor) 13D, and the like. The determination unit 12D is provided with an input interface surface IF, a binary unit KDD, and a correction unit SYD.

Further, in the frosting state detecting device 1D of the fourth embodiment, the configuration and function of the frosting state detecting devices 1 and 1B according to the first and second embodiments described above and the detecting device of the third embodiment 1C has the same part. For the same part, some will be omitted here for simplification. Further, the same portions will be described in more detail below, and the following description is also applicable to the same portions of the frosting state detecting devices 1, 1B and the detecting device 1C.

As shown in FIGS. 10 to 12, the moisture sensor 13D has the first electrodes 22Da and b and the second electrode 23D and the ground electrodes 24a and b which form a pattern on the surface of the substrate 21D.

That is to say, the electrodes 22Da, b, 23D, 24a, and b are formed in a rectangular pattern, and are disposed with gaps GP and GPG therebetween. The second electrode 23D is disposed at a central portion of the substrate 21D. The first electrodes 22Da and b are disposed on both sides of the second electrode 23D and are provided with a gap GP between the second electrode 23D and the side between the sides closer to each other than the outer diameter of the cooling tube RKP. smaller.

The size of the moisture sensor 13D can be exemplified as follows. The substrate 21D is, for example, a rectangle having a length of about 20 to 30 mm and a width of about 10 to 15 mm. The width of the second electrode 23D is, for example, several millimeters, and more specifically, about 3 millimeters. The widths of the first electrodes 22Da, b are, for example, several millimeters, and more specifically, two to three millimeters. The widths of the ground electrodes 24a, b are, for example, several millimeters, and more specifically, about 2 to 3 millimeters.

Further, the two gaps GP between the second electrode 23D and the first electrodes 22Da and b are, for example, one tenth and tenths of a millimeter, and more specifically, about 0.1 millimeters. The two gaps GPG between the electrodes 22Da, b and the ground electrodes 24a, b are, for example, one or several millimeters, and more specifically, about 1 millimeter.

The moisture sensor 13D is attached to the cooling pipe RKP so that moisture can adhere to one of the second electrode 23D, one of the first electrodes 22Da and b, the gap GP, and the outer surface of the cooling pipe RKP.

Specifically, as shown in Figures 10 to 12, it is fixed as the second The central portion of the electrode 23D in the width direction contacts the surface of the cooling tube RKP.

When the cooling pipe RKP is cooled by the operation of the refrigerator RK, as shown in Fig. 12, moisture (water droplets) MZ adheres to the surface of the cooling pipe RKP. The moisture MZ enters the gap GP, and the electric resistance Zs between the first electrode 22Da and the second electrode 23D is lowered.

Further, at the time when the refrigerator RK is initially started to operate, there is a possibility that the surface of the cooling pipe RKP is in a dry state without adhering moisture MZ.

As described above, the electric resistance Zs of the moisture sensor 13D changes depending on whether there is a state of moisture MZ in the gaps GP and GPG, that is, a state of water droplets (dew condensation state), a frosting state, or a dry state. Moreover, in the state of this mixing, it changes with the ratio, the amount of moisture MZ, and the like. Moreover, the frosting state can be said to be a frozen state or a partially frozen state.

Further, the relative dielectric constant ε in the water drop state, the frozen state, and the dry state is about 80, 4.2, and 1, respectively.

The control unit RKC of the refrigerator RK controls the on/off of the cooling device, that is, the operation or the stop of the cooling device, based on the detection signal S2a from the frosting state detecting device 1D. When the state of the water droplet is detected by the moisture sensor 13D, the detection signal S2a is turned off, that is, L, and the cooling device is operated at this time. Further, when the frost state is detected by the moisture sensor 13D, the detection signal S2a is turned on, that is, H, and the cooling device is stopped.

Since the refrigerator RK must be started (operated) in the initial dry state, the detection signal S2a becomes OFF in the dry state, that is, L. In order to detect the dry state to forcibly set the detection signal S2a to cut off, The frosting state detecting device 1D of the present embodiment is provided with a correction unit SYD. The details will be described later.

As shown in Fig. 13, the frosting state detecting device 1D is provided with an output of the detection signals S2a, b, and a connector CN1D for connecting the positive side (VDD) and the negative side (ground line GL) of the power supply circuit. The ground line GL is also the ground line for the detection signals S2a, b.

In the frosting state detecting device 1D, a single power source is used as the power source circuit. However, it is also possible to use a dual power supply consisting of two systems of a positive power supply (+VDD) and a negative power supply (-VDD). At this time, the positive side (VDD) of the frosting state detecting device 1D is connected to the positive power source (+VDD) of the power supply circuit, and the ground line GL of the frosting state detecting device 1D is connected to the voltage of the power supply circuit, and is connected to the ground of the power supply circuit. Line GL or negative power (-VDD) is sufficient.

As for the drive unit 11D, the configuration and function are the same as those of the drive unit 11 described above. The signal generating unit GSD formed in the driving unit 11D is the same as the signal generating unit GS described above. The output side of the signal generating unit GSD is connected in series with a resistor R2.

As shown in Fig. 15(A), the output voltage S0 of the signal generating portion GSD is a rectangular wave which is turned on/off between 0 volts of the potential of the ground line GL and the voltage VDD applied to the positive side.

The output voltage S1 of the driving unit 11D is formed by dividing the voltage S0 by the resistor Z2 and the resistance Zs of the moisture sensor 13D, and is lower than the output voltage S0 as shown in Fig. 15(B).

That is, when the water adheres to the moisture sensor 13D in the state of water droplets, the amount of decrease in voltage is increased due to a decrease in electric resistance, so the output voltage S1 is as The dotted line shows a relatively low voltage.

When the water adhering to the moisture sensor 13D freezes to a frosted state, the amount of decrease in voltage is reduced by the increase in the resistance Zs. Therefore, the output voltage S1 is a relatively high voltage as indicated by a one-dot chain line.

When the water sensor and the frost are not attached to the moisture sensor 13D, that is, when the periphery of the moisture sensor 13D is in a dry state in which only the space is dry, since the resistance Zs is maximum, the voltage is hardly reduced, so the output voltage S1 is as shown by the solid line. The highest voltage.

Further, the height (size) of the output voltage S1 is various values in combination with a dry state, a frosting state, a water drop state, and a moisture amount.

Therefore, the water drop state and the frosting state can be determined based on the threshold value th1 shown in Fig. 15(B). Further, as will be described later, the threshold value th1 may be set to two threshold values th1a and th1b, and any one of the threshold values th1a or th1b may be selected depending on the direction in which the state changes. Thereby, hysteresis will be given during the binarization.

Further, in the frosting state detecting device 1D, the threshold values th1, th1a, and th1b are set with respect to the voltage S1c described below, and the meaning is the same in the binarization.

Further, the frosting state and the dry state can be determined by the threshold value th2 shown in Fig. 15(B).

Further, in the frosting state detecting device 1D, the threshold value th2 is set with respect to the voltage obtained by dividing the output voltage S1, and the meaning in the binarization is the same.

The output voltage S1 of the driving portion 11D, that is, the output voltage S1 of the moisture sensor 13D, is transmitted through the input composed of the resistor R3 and the capacitor C2. The face IF is used to input the binarization unit KDD. Since the voltage S1c on the output side of the input dielectric portion IF is removed by the capacitor C2, as shown in Fig. 15(C), the positive and negative signals are vibrated up and down with the reference voltage (bias) Va as the center.

That is, the maximum amplitude of the voltage S1c of the input binarization unit KDD is actually smaller than the output voltage S1 of the moisture sensor 13D, and the positive or negative direction is obtained when the reference voltage (bias) Va is set to 0 volt. The maximum value is 1/2.

Fig. 16 shows the state in which the detection signal S2a is outputted in accordance with the output voltage S1c from the input dielectric portion IF in the binary unit KDD. In particular, Fig. 16(B) and Fig. 16(C) show the state when the detection signal S2a is changed from L to H, and the state when the detection signal S2a is changed from H to L, respectively.

In Fig. 16(A)(B)(C), the threshold TH is a threshold used for logical decision in the logic circuit of the binarization unit KDD. That is, when the output voltage S1c is equal to or less than the threshold TH, the input will be processed as L, and the detection signal S2a will be turned off. When the output voltage S1c exceeds the threshold TH, the input will be processed as H, and the detection signal S2a will be turned on.

Further, the reference voltage (bias) Va in the output voltage S1c is set to an appropriate value which is lower than the threshold TH to discriminate the value of the water drop state or the frosting state.

The difference (TH-Va) between the threshold TH and the reference voltage (bias) Va is a threshold value th1 for comparing the output voltage S1c for binarization. That is, the difference (TH-Va) is an example of the "threshold value" and the "first threshold value" in the present invention.

Also, the threshold TH is for output from the moisture sensor 13D The threshold value of the voltage S1 binarization is an example of the "threshold value" and the "first threshold value" in the present invention. However, the relationship between the threshold TH itself and the magnitude of the threshold value th2 does not directly correspond to the "first threshold value" in the present invention.

The value of the threshold value th1 can be appropriately set by appropriately setting the bias voltage Va.

Therefore, as shown on the left side of Fig. 16(A), when the frosting state is detected by the moisture sensor 13D, that is, when the output voltage S1c is higher than the threshold value th1, since one of the output voltages S1c exceeds the threshold TH, The input of the KDD of the elementizing unit becomes H, and the detection signal S2a becomes conductive.

Further, as shown on the right side of Fig. 16(A), when the water droplet state is detected by the moisture sensor 13D, that is, when the output voltage S1c is lower than the threshold value th1, since the output voltage S1c does not exceed the threshold value TH, the input becomes L. The detection signal S2a becomes the cutoff.

Further, in the binary unit KDD, when the detection signal S2a is turned on, the capacitor C3 is provided with an appropriate number of integrated circuits to temporarily maintain the state. Therefore, in the present embodiment, the maximum value of the output voltage S1c at the time of binarization may be noted.

Further, as shown in Fig. 16(B), when the detection signal S2a is off, that is, when the moisture sensor 13D detects the state of water droplets, the relatively low voltage Vaa is set to the bias voltage Va. Thereby, the difference (TH-Vaa) between the threshold TH and the bias voltage Vaa is relatively increased, and a relatively large threshold value th1a can be set.

When the output voltage S1c from the input dielectric surface IF exceeds the threshold value th1a, it is detected that the transition from the water drop state to the frosting state is detected, and the detection signal S2a is output.

Further, as shown in Fig. 16(B), when the detection signal S2a is turned on, that is, when the moisture sensor 13D detects the frosting state, the relatively high voltage Vab is set to the bias voltage Va. Thereby, the difference (TH-Vab) between the threshold TH and the bias voltage Vab is relatively decreased, and a relatively small threshold value th1b can be set.

When the output voltage S1c from the input dielectric surface IF becomes equal to or less than the threshold value th1b, it is detected that the transition from the frosting state to the water droplet state is detected, and the detection signal S2a is turned off.

Fig. 17 shows a state in which the correction unit SYD is determined to be in a dry state by the output voltage S1 of the moisture sensor 13D, and the detection signal S2a is turned off in the dry state. Further, the correction unit SYD of the present embodiment is constituted by the NOT circuit Q6.

In Fig. 17, the voltage S1d input to the correction unit SYD is a voltage obtained by dividing the resistor R11 and the resistor R12 which will be described later from the output voltage S1 of the moisture sensor 13D.

The threshold TH2 is a threshold used for logical determination in the logic circuit of the correction unit SYD. That is, when the output voltage S1d is equal to or less than the threshold TH2, the input will be processed as L, and the output of the correction unit SYD will be maintained at H. When the voltage S1d exceeds the threshold TH2, the input will be processed as H, and the output of the correction unit SYD will be L. When the output of the correction unit SYD becomes L, the output voltage S1c of the input interface IF will become approximately 0 volts.

Here, the threshold TH2 is a threshold value th2 for discriminating whether it is a dry state or a frosting state. In this sense, the threshold TH2 is an example of the "second threshold" in the present invention. However, the threshold value TH2 itself does not directly correspond to the "second threshold value" in the present invention in relation to the magnitude of the threshold value th1.

Therefore, as shown on the left side of Fig. 17, when the dry state is detected by the moisture sensor 13D, that is, when the voltage S1d is higher than the threshold TH2, since one of the voltages S1d exceeds the threshold TH2, the output of the correction unit SYD becomes L. . Thereby, the voltage S1c becomes about 0 volts, which is smaller than any of the thresholds th1a, b, and the detection signal S2a is forcibly turned off.

Further, as shown on the right side of Fig. 17, when the frost state is detected by the moisture sensor 13D, that is, when the voltage S1d is lower than the threshold TH2, since the voltage S1d does not exceed the threshold TH2, the output of the correction portion SYD is maintained. At H. In this manner, the correction unit SYD does not affect the voltage S1c, but the discrimination unit KDD determines the corresponding voltage S1c.

The binary unit KDD compares the input voltage S1c with the threshold value th1 to perform binarization, and outputs a detection signal.

In other words, when the output voltage S1c from the input dielectric surface IF is larger than the threshold value th1, the binary unit KDD freezes the water between the first electrodes 22Da and b and the second electrode 23D and changes to a frosty state. The signal is output as the detection signal S2a.

When the output voltage S1 from the moisture sensor 13D is larger than the threshold value th2, the detection signal S2a is not outputted, indicating that the first electrode 22Da, b and the second electrode 23D are in a dry state without moisture. That is, the detection signal S2a is forcibly turned off in the dry state, and the correction portion SYD is provided for this correction.

In other words, when the output voltage S1 from the moisture sensor 13D is larger than the threshold value th2, the correction unit SYD reduces the output voltage S1c from the input interface surface IF to the threshold value th1 or less, thereby correcting that the detection signal S2a is not output.

Further, the threshold value th2 is larger than the threshold value th1, that is, th2>th1.

The configuration and operation of the determination unit 12D will be described in detail below with reference to Figs. 13 to 18 .

In Fig. 13, the binarization unit KDD is composed of NOT circuits Q3 to Q5, resistors R4, R5, R6, and R10, a capacitor C3, a diode D1, and the like. The binarization unit KDD is an output side that connects the input interface face IF.

Further, the correction unit SYD is constituted by the NOT circuit Q6, the resistors R11 to R13, the capacitor C4, the diode D2, and the like. The binarization unit KDD can be regarded as being connected in parallel with the input media face IF.

Further, each of the NOT circuits Q1 to Q6 is constituted by a NOT circuit element of a CMOS (Complementary Metal Oxide Semiconductor).

That is, as shown in FIG. 14, the NOT circuits Q1 to Q6 are logic inversi conduction circuits in which the p-channel and n-channel MOSFETs are configured in a complementary gate structure. Component composition. When the input gate IN is L (low level), the output becomes H (high level), and when the input gate IN is H, the gate OUT becomes L. The NOT circuits Q11 to Q14 used in the second embodiment are also the same.

As such a NOT circuit element, for example, an integrated circuit element of a commercially available model number 14068B can be used. In the integrated circuit device of the type 14068B, six NOT circuit elements are housed in one package, and all of the NOT circuits Q1 to Q6 necessary for the frost state detecting device 1D can be provided by one integrated circuit element.

In such a NOT circuit Q3, the threshold TH of the logic inversion is electric The source voltage is near 1/2 of the voltage VDD. That is, the output becomes L when the voltage of the input gate IN exceeds VDD/2, and becomes H when the voltage of the input gate IN becomes VDD/2 or less.

Here, when the bias voltage Va is applied to the input gate IN of the NOT circuit Q3, the output voltage S1c from the input dielectric surface IF exceeds the difference (TH-Va) between the threshold TH and the bias voltage Va, and the output becomes L, when the output is When the voltage S1c becomes equal to or less than (TH-Va), the output becomes H. That is, the difference (TH-Va) becomes the threshold value th1.

Therefore, the threshold value th1 can be changed by changing the value of the bias voltage Va. That is, when the bias voltage Va is set to a voltage lower than the threshold TH (Va<TH), the difference (TH-Va) is increased and the threshold value th1 is increased, and the bias voltage Va is increased (TH). -Va) decreases while the threshold th1 decreases.

In the present embodiment, when the output of the NOT circuit Q3 is H, the bias voltage Va is set to a relatively small voltage Vaa, and the threshold value th1a used when the output is switched from H to L is set to be high; the output of the NOT circuit Q3 is set. In the case of L, the bias voltage Va is set to a voltage Vab (Vab > Vaa) larger than the voltage Vaa, and the threshold value th1b used when the output is switched from H to L is set to be low. That is, th1a>th1b (see Fig. 15 and Fig. 18).

In this manner, the threshold value th1a for switching H to L and the two threshold values th1a and b for switching L to the threshold value th1 of H are set.

In the binarization unit KDD shown in Fig. 13, since two threshold values th1a and b are set, positive feedback is caused by the resistor R10 from the output side of the NOT circuit Q4 to the input side of the NOT circuit Q3. The resistor R10 is for outputting a state in accordance with the change bias voltage Va when binarization is performed by the NOT circuit Q3. A feedback resistor that gives a threshold value of th1 hysteresis.

That is, the output voltage of the NOT circuit Q4 is divided by the two resistors R10 and R5 and added to the input side of the NOT circuit Q3. The input side of the NOT circuit Q3 is subjected to a voltage VDD to which a power supply via the resistor R4 is applied, and the sum of the voltages divided by the two resistors R4 and R5 and the voltage fed back by the resistor R10 becomes the bias voltage Va of the NOT circuit Q3.

When the output of the NOT circuit Q4 is H, the input side of the NOT circuit Q3 is subjected to a relatively high bias voltage Vab, and when the output of the NOT circuit Q4 is L, the input side of the NOT circuit Q3 is subjected to a relatively low bias voltage Vaa.

Therefore, for example, when the output of the NOT circuit Q3 is H, that is, the output of the NOT circuit Q4 is L, and when the detection signal S2a is not output (when not in the frosting state), the output voltage is input from the input dielectric portion IF to the NOT circuit Q3. S1c is in a state lower than the threshold value th1a, and the output of the NOT circuit Q3 is switched from H to L because the output voltage S1c exceeds the threshold value th1a. At this time, the bias voltage Va rises to become the bias voltage Vab, and the threshold value th1 decreases to the threshold value th1b.

When the output of the NOT circuit Q3 is L, that is, when the output of the NOT circuit Q4 is H, when the output detection signal S2a is output (in the frost state), the output voltage S1c is input from the input interface IF to the NOT circuit Q3. In a state higher than the threshold value th1b, the output of the NOT circuit Q3 is switched from L to H because the output voltage S1c falls below the threshold value th1b. At this time, the bias voltage Va is lowered to the bias voltage Vaa, and the threshold value th1 is increased to the threshold value th1a.

Further, as described above, the output side of the NOT circuit Q3, that is, the capacitor C3 for integration is connected between the input side of the NOT circuit Q4 and the ground line GL, and the charge input to the NOT circuit Q4 is accumulated to be intense in a short time. The voltage change does not occur. The capacity of the capacitor C3 is, for example, about 0.001 μF to 0.1 μf, and specific example is about 0.01 μf. The capacitor C3 is an example of the "second capacity element" in the present invention.

Next, the operation of the correction unit SYD will be described.

As described above, the correction unit SYD divides the output voltage S1 from the moisture sensor 13D by the resistor R11 and the resistor R12, and then inputs it to the NOT circuit Q6 as the voltage S1d. The values of the resistors R11 and R12 are set such that when the voltage S1d is larger than the threshold TH2, that is, when the voltage S1 is larger than the threshold value th2, the output of the NOT circuit Q6 can be set to L.

When the output of the NOT circuit Q6 is L, the potential on the input side of the NOT circuit Q3 is connected to the ground line GL through the resistor R13 and the diode D2, and the potential on the input side of the NOT circuit Q3 is lowered to the threshold value th1b or less. As a result, the output of the NOT circuit Q3 becomes H, and the output of the NOT circuit Q4 becomes L.

Further, the capacitor C4 adjusts the phase of the NOT circuit Q3 on the input side or suppresses a drastic change in potential to stabilize the operation.

In this manner, when the output voltage S1 from the moisture sensor 13D is the threshold value th2, the correction unit SYD lowers the output voltage S1c from the input interface IF to below the threshold value th1b, so that the detection signal S2a is not output, that is, the detection signal is detected. S2a is corrected to cutoff.

In Fig. 18, the power of the refrigerator RK is turned on at time t1. At time t1, the periphery of the cooling pipe RKP is in a dry state, and the moisture sensor 13D detects that the dry state outputs a voltage S1 higher than the threshold value th2. At this time, the output of the correction unit SYD is L, the voltage S1c input to the binarization unit KDD is 0 volt, and the detection signal S2a is forcibly turned off. Therefore, freezing The cooling device of the machine RK starts to operate, and the cooling pipe RKP will be cooled.

At this time, since the input side of the NOT circuit Q3 is L, the relatively low bias voltage Vaa is set, so the threshold value th1a is set to be relatively high.

Further, since dew condensation occurs due to the operation of the refrigerator RK, the output voltage S1 of the moisture sensor 13D falls below the threshold value th2 at time t2, and the output of the NOT circuit Q6 becomes H. However, since the output voltage S1 is drastically lowered due to condensation at this time, and the integration effect of the capacitors C3 and C4 is provided, the output of the NOT circuit Q4 does not become H.

On the other hand, since the dew condensation water gradually freezes, the voltage S1c gradually increases, and when the threshold value th1a is exceeded at time t3, the frosting state is detected, and the detection signal S2a is turned on.

When the detection signal S2a is turned on, the cooling device of the refrigerator RK is stopped, and the temperature of the cooling pipe RKP is gradually increased.

At this time, since the input side of the NOT circuit Q3 is H, the higher bias voltage Vab is set, and thereby the relatively lower threshold value th1b is set.

As the temperature rises and the frost melts and gradually returns to the water drop state, the voltage S1c gradually decreases, and when the threshold value th1b or less is reached at time t4, the water droplet state is detected, and the detection signal S2a is turned off. Thereby, the operation of the cooling device of the freezer RK will start again.

In other words, as shown in Fig. 19, the refrigerator RK of the present embodiment is a cycle in which the refrigerator RK is restarted from the dry state, the operation is stopped when the water is in a frosted state, and the operation is resumed when the water droplets are in a state of water droplets.

As described above, the frosting state detecting device 1D of the present embodiment can detect the frosting state in the refrigerator RK or detect the frosting state. The state shifts to the state of water droplets, and the operation and stop of the cooling device can be appropriately switched accordingly.

Further, since the threshold value th for detection when moving from the water droplet state to the frosting state is different from the threshold value for detecting from the frosting state to the water droplet state, the operation and the stop of the cooling device can be more appropriately switched.

Further, when the refrigerator RK is initially started (operated), the detection signal S2a is forcibly turned off even in the dry state, and the cooling device is smoothly started.

The frosting state detecting device 1D of the present embodiment can be constituted by one integrated circuit element having the NOT circuits Q1 to Q6, a small number of electronic components such as a resistor and a capacitor, and can be incorporated into the moisture sensing by the electronic components. The substrate 21D of the device 13D is fabricated. Therefore, the frosting state detecting device 1D can be made compact and lightweight, can be manufactured inexpensively, and can be easily attached to the refrigerator RK. Moreover, the control unit RKC of the freezer RK can be connected by three wires, and it is easy to install and maintain.

As described above, according to the present embodiment, it is possible to detect the frosting state with sufficient accuracy without providing the camouflage electrode as in the related art, and it is possible to provide the frosting state detecting device 1D having a simple configuration.

The refrigerator RK of the above-described embodiment can switch the cooling device in conjunction with the detection signal S2a of the frosting state detecting device 1D, and can increase or decrease the cooling capacity by controlling the rotation speed of the inverter motor that drives the cooling device.

Further, the frosting state detecting device 1D may control the cooling device without depending on the detection signal S2a, and for example, may provide a defrosting heater for defrosting, and control The defrost heater is activated when a frosting condition is detected.

Further, in the frosting state detecting device 1D, a display output portion such as a light emitting diode may be provided to display the ON (ON) or OFF (OFF) of the detection signal S2a.

Further, as described above, in the determination unit 12D, when the output voltage S1 from the moisture sensor 13D is binarized to output a detection signal, various voltages S1c, S1d, and various types related to the output voltage S1 are used. Thresholds th1, th1a, th1b, TH, TH2. These are examples of "output voltage from a capacitive sensor" or "threshold value", "first threshold value" and "second threshold value" in the present invention. However, voltages or thresholds other than those described above may be used in accordance with circuits, components, and the like.

Further, the NOT circuit Q3 described above is an example of the "first NOT circuit" in the present invention. Further, the NOT circuit Q6 is an example of the "second NOT circuit" in the present invention.

In the various embodiments described above, the frost sensors 13 and 13B or the moisture sensors 13C and 13D can be attached to the wall of the cooler RP, the cooling pipe RKP, other pipes, the cooling fan, the cold storage, or the like, or the like. Premises.

A comparator (comparison circuit) can also be used instead of the NOT circuit Q3 described above. At this time, the voltages S1, S1b, and S1c input to the determination units 12, 12B, 12C, and 12D and the thresholds th, th1, th1a, and th1b set by the resistors R4 and R5 may be compared. Since the voltages S1, S1b, and S1c are alternating current signals, a DC voltage component (current flow) exceeding the threshold th appears on the output side of the comparator. It can be smoothed and then binarized. In order to obtain the corresponding communication signal The binary signals of the sizes S1, S1b, and S1c can also be used in various other detection or detection methods.

Further, the input interface IF, IFB, binary unit KD, KDB, KDC, KDD, display output unit HS, HSB, HSC, drive units 11, 11C, 11D, determination units 12, 12B, 12C, 12D, frosting Configuration, structure, circuit, shape, size, number, and number of each or all of the inductors 13, the moisture sensors 13C, 13D, 30, 30B, and 30C, the frosting state detecting devices 1, 1B, and 1D, or the detecting device 1C The material, configuration, frequency, and waveform can be appropriately changed in accordance with the gist of the present invention.

11C‧‧‧Drive Department

12C‧‧‧Decision Department

13C‧‧‧Moisture sensor

1C‧‧‧Detection device

21C‧‧‧Substrate

22C‧‧‧1st graphic electrode

23C‧‧‧2nd graphic electrode

C1, C3‧‧‧ capacitor

CN1‧‧‧Connector

D1‧‧‧ diode

GL‧‧‧ grounding wire

HSC‧‧‧Output Department

KDC‧‧‧Dualization Department

LEDa, LEDb‧‧‧Lighting diode

Q1, Q2, Q3, Q4, Q5‧‧‧NOT circuits

R1, R4, R5, R6, R7, R8‧‧‧ resistors

S1a‧‧‧ exchange signal

S1b‧‧‧ output voltage

S2a, S2b‧‧‧ detection signals

T11‧‧‧ output terminal

T12‧‧‧ input terminal

Ta, Tb‧‧‧ terminals

+VDD‧‧‧ positive power supply

-VDD‧‧‧Negative power supply

Claims (15)

A capacitive moisture detecting device that detects a change in capacitance in response to a change in the ratio of moisture in a surrounding environment or a state, and includes a capacitive sensor having first and second electrodes arranged to face each other. And the capacitance varies depending on the ratio or state of moisture between the first electrode and the second electrode; the driving unit applies an alternating current signal to the capacitance sensor; and the determining unit is based on an output voltage from the capacitance sensor. The size is doubled and the detection signal of the on or off is outputted, and the determination unit has an input interface surface, and is a first resistance part and a capacitor part connected in series to each other and connected to the output side of the capacitance sensor. a duality unit connected to the output side of the input interface surface, and outputting a water freeze between the first electrode and the second electrode when an output voltage from the input interface surface is greater than a first threshold a frost-like frosting state detection signal as the detection signal; and a correction portion at the output from the capacitive sensor To reduce the pressure is greater than the first threshold value or less than the first threshold value of the second larger threshold value, from the output voltage of the input interface section. The capacitive moisture detecting device of claim 1, wherein the capacitance sensor is connected between an output of the driving portion and a ground line, wherein the determining portion compares an output voltage from the capacitance sensor with a preset threshold To perform the aforementioned binarization. The capacitance type moisture detecting device according to claim 2, wherein the determination unit outputs a frost indicating that the moisture between the first electrode and the second electrode is frozen when the output voltage from the capacitance sensor is greater than a first threshold The frosting state detection signal is the detection signal, and when the output voltage from the capacitance sensor is greater than a second threshold greater than the first threshold, the frosting state detection signal is not outputted to indicate the first electrode It is dried without moisture between the second electrode. The capacitive moisture detecting device of claim 1, wherein the capacitance sensor is connected between an output of the driving portion and an input of the determining portion, wherein the determining portion compares an output voltage from the capacitance sensor with a predetermined The threshold is set to perform the aforementioned binarization. The capacitance type moisture detecting device according to claim 4, wherein the determination unit outputs a frost indicating that the water between the first electrode and the second electrode is frozen when the output voltage from the capacitance sensor is less than the first threshold. The frosting state detection signal is the detection signal, and when the output voltage from the capacitance sensor is smaller than a second threshold smaller than the first threshold, the frosting state detection signal is not outputted to indicate the first The electrode and the second electrode are dried without moisture. The capacitive moisture detecting device according to claim 2, wherein the driving unit includes: a signal generating unit that generates the alternating current signal; and a resistance component that connects the output side of the signal generating unit. The capacitive moisture detecting device according to claim 1, wherein the binarization unit includes: a first NOT circuit of the CMOS, wherein an output voltage from the input interface is input, and the binary is performed by the first threshold; and the integration is performed. The second capacitor component is connected to the output side of the first NOT circuit; the second NOT circuit of the CMOS inputs the terminal voltage of the second capacitor component, and the input voltage is inverted to output the detection signal; the feedback resistor is The output side of the second NOT circuit is connected to the input side of the first NOT circuit to provide a hysteresis during the binarization. The capacitance type moisture detecting device according to claim 7, wherein the correction unit includes: a third NOT circuit of the CMOS, wherein an output voltage from the capacitance sensor is input, and when the input voltage is greater than the second threshold, the output is L; and The pole body is connected in reverse between the output side of the third NOT circuit and the input side of the first NOT circuit. The capacitive moisture detecting device according to claim 1, wherein the capacitance sensor is mounted such that the first electrode and the second electrode form a pattern on a surface of the substrate, and the second electrode contacts a peripheral surface of the cooling tube, and It is possible to detect whether or not there is a frosty state in which the moisture in the atmosphere due to the cooling effect of the cooling tube is frozen. A capacitive moisture detecting device according to claim 9, wherein The second electrode has a rectangular pattern on the surface of the substrate, and the first electrode is in a state in which a gap is provided between both sides of the second electrode and the second electrode, and the side portions are close to each other. a rectangular pattern is formed on the surface of the substrate so that the distance between the two is smaller than the outer diameter of the cooling tube, and the capacitance sensor is attached to the cooling tube so that moisture adheres to one of the second electrodes. One of the first electrode, the gap, and the outer circumferential surface of the cooling tube. The capacitive moisture detecting device according to claim 1, wherein an output terminal of the driving unit and an input terminal of the determining unit are provided on a substrate, and two terminals connecting the first electrode and the second electrode are adjacent to each other The output terminal, the input terminal, and the two terminals are connected to the output terminal of the driving unit and the determining unit by connecting the capacitive inductor in series or in parallel by the wiring connection on the substrate. Input terminal. The capacitive moisture detecting device according to claim 2 or 4, wherein the first electrode and the second electrode are two electrode rods which are buried in the soil at a proper interval in parallel with each other, and the capacitor The sensor is a state of detecting moisture in the aforementioned soil. The capacitive moisture detecting device according to claim 2 or 4, wherein the first electrode and the second electrode are in parallel with each other at an appropriate interval The outer circumference of the container is wound apart, and the capacitance sensor detects the liquid level of the liquid in the container. The capacitive moisture detecting device according to claim 2 or 4, wherein the first electrode and the second electrode are wound in a state of being opposed to each other while being in a state of being opposed to each other, and are wound around the outer circumference of the container for half a week. The aforementioned capacitive sensor is for detecting the liquid level of the liquid in the container. A refrigerator type moisture detecting device according to any one of claims 1 to 12.