CN111812164A

CN111812164A - Adhering moisture detection device, adhering moisture detection method, electrical device, and log output system

Info

Publication number: CN111812164A
Application number: CN202010125128.6A
Authority: CN
Inventors: 中根健智
Original assignee: MinebeaMitsumi Inc
Current assignee: MinebeaMitsumi Inc
Priority date: 2019-04-10
Filing date: 2020-02-27
Publication date: 2020-10-23
Also published as: KR20200119713A; JP2020173245A

Abstract

The invention provides a small-sized and inexpensive adhering moisture detecting device capable of quickly and accurately detecting the adhering moisture such as dew condensation and frost formation. The adhering moisture detection device is provided with: a sensor chip including a humidity detection portion having a detection surface for detecting humidity and a heating portion for heating the detection surface; and an adhering moisture determination unit that determines whether or not moisture adheres to the detection surface based on a difference in change in the humidity detected by the humidity detection unit after the heating unit is started to heat.

Description

Adhering moisture detection device, adhering moisture detection method, electrical device, and log output system

Technical Field

The invention relates to an adhering moisture detection device, an adhering moisture detection method, an electrical device, and a log output system.

Background

Some recent suspension hard disk drives (HDD drives) have a condensation sensor mounted thereon for the purpose of preventing damage to the head due to adhesion of water. In such a hard disk drive mounted with a dew condensation sensor, it is proposed to temporarily retract a magnetic head when dew condensation is detected by the dew condensation sensor, and rotate a magnetic disk until dew condensation is not detected (see patent document 1).

Further, since the projector in recent years is provided with a cooling mechanism, there is a possibility that water droplets caused by dew condensation generated under the influence of the cooling mechanism are scattered in the closed container and adhere to the optical device. In view of the above, it has been proposed to mount a condensation sensor in a projector and control a heat exchanger based on a detection result of a condensation state by the condensation sensor (see patent document 2).

In recent years, refrigerators having a vegetable room suitable for storing vegetables in addition to a refrigerator room have become widespread. The temperature of the vegetable compartment is maintained higher than the refrigerating compartment, and in addition, the humidity of the vegetable compartment is maintained higher than the refrigerating compartment to prevent the vegetables from drying. Therefore, dew condensation is likely to occur in the refrigerator, and if dew condensation occurs, vegetables may be rotten.

In view of the above, it has been proposed to prevent dew condensation by measuring the humidity of the vegetable room with a humidity sensor and introducing air from an air blowing unit into the vegetable room in accordance with the measured humidity (see patent document 3). In addition, patent document 1 proposes providing a dew condensation sensor to quickly and accurately detect the dew condensation state in the vegetable room.

The above documents describe that a dew condensation sensor is mounted on an electrical device such as a hard disk drive, a projector, and a refrigerator, and patent document 3 describes that a highly sensitive dew condensation detection sensor made of a material such as aluminum is used as the dew condensation sensor.

Normally, dew condensation is detected by a resistance type dew condensation sensor (see patent document 4), and frost formation is detected by a resistance type frost formation sensor. In addition, dew point, frost point, and the like are detected using an optical dew point meter or the like.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 10-320902;

patent document 2: japanese patent laid-open publication No. 2016-;

patent document 3: japanese patent laid-open publication No. 2014-122757;

patent document 4: japanese patent laid-open No. 11-002617.

Disclosure of Invention

Technical problem

The sensors for detecting dew condensation, frost formation, and the like provided in electrical devices such as hard disk drives, projectors, and refrigerators as described above are required to be small and inexpensive, and to be capable of quickly and accurately detecting dew condensation, frost formation, and the like.

However, although a resistive condensation sensor, a frost formation sensor, and the like are inexpensive, there is a problem that detection accuracy deteriorates as the number of times of detection of condensation, frost formation, and the like increases in principle. On the other hand, optical dew point hygrometers employ optical devices such as lasers and photodetectors, which are expensive and difficult to miniaturize. Therefore, the resistance type dew condensation sensor, the frost formation sensor, and the optical dew point instrument are not preferably mounted on the above-described electric apparatus.

The same problem also exists with respect to a condensation sensor provided in a bathroom or the like.

The invention aims to provide a small and cheap adhering moisture detecting device which can quickly and accurately detect the adhering moisture such as condensation and frosting.

Technical scheme

The disclosed technology provides an adhering moisture detection device, comprising: a sensor chip including a humidity detection portion having a detection surface for detecting humidity and a heating portion for heating the detection surface; and an adhering moisture determination unit that determines whether or not moisture adheres to the detection surface based on a difference in change in the humidity detected by the humidity detection unit after the heating unit is started to heat.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, an attached moisture detection device is provided which can detect the attachment of moisture such as dew condensation and frost formation quickly and accurately, and which is small and inexpensive.

Drawings

Fig. 1 is a schematic view showing an overall configuration of a refrigerator of a first embodiment of the present invention.

Fig. 2 is a diagram illustrating a schematic configuration of a sensor module of an embodiment of the present invention.

Fig. 3 is a sectional view schematically showing a section along the line a-a in fig. 2.

Fig. 4 is a plan view of the humidity detecting device in a state where the mold resin is removed.

Fig. 5 is a schematic plan view showing the configuration of the sensor chip.

Fig. 6 is a circuit diagram illustrating a configuration of the ESD protection circuit.

Fig. 7 is a diagram illustrating a layer structure of an NMOS transistor constituting the ESD protection circuit.

Fig. 8 is a circuit diagram illustrating the configuration of the humidity detection portion.

Fig. 9 is a circuit diagram illustrating the arrangement of the temperature detection section.

Fig. 10 is a schematic cross-sectional view for explaining the element structure of the sensor chip.

Fig. 11 is a plan view illustrating shapes of the lower electrode and the upper electrode.

Fig. 12 is a plan view illustrating the shape of the n-type diffusion layer constituting the heating portion.

Fig. 13 is a block diagram illustrating a functional structure of an ASIC chip.

Fig. 14 is a flowchart for explaining the exposure determination process.

Fig. 15 is a graph showing the result of the first experiment in the case where condensation does not occur.

Fig. 16 is a graph showing the result of the second experiment in the case where condensation does not occur.

Fig. 17 is a graph of experimental results in the case where condensation has occurred.

Fig. 18 is a graph illustrating a relationship between a difference in humidity after heating is started and time.

Fig. 19 is a graph illustrating a relationship between a difference in humidity after heating is started and time.

Fig. 20 is a graph illustrating the relationship of humidity to temperature corresponding to a dew point of N ℃.

Fig. 21 is a flowchart illustrating a dew condensation determination process having a dew condensation removal determination process according to a modification.

Fig. 22 is a diagram illustrating changes in humidity and temperature when heating is started in a mist-like condensation environment.

Fig. 23 is a diagram illustrating the amount of change in temperature of the sensor chip when heating is started in an environment where condensation does not occur.

Fig. 24 is a diagram illustrating a relationship between the dew condensation water amount and the temperature change coefficient Y.

Fig. 25 is a flowchart for explaining the dew condensation water amount estimation process executed simultaneously with the dew condensation determination process.

Fig. 26 is a flowchart illustrating a calculation process of the humidity change coefficient.

Fig. 27 is a flowchart illustrating a process of calculating a temperature change coefficient.

Fig. 28 is a flowchart illustrating the process of determining the amount of dew condensation water.

Fig. 29 is a flowchart illustrating a modification of the preliminary determination processing according to the first embodiment of the present invention.

Fig. 30 is a diagram illustrating a sensor chip in which a water repellent film is provided on a detection surface.

Fig. 31 is a schematic view showing an overall configuration of a refrigerator of a second embodiment of the present invention.

Fig. 32 is a flowchart illustrating a modification of the pre-determination process according to the second embodiment of the present invention.

Fig. 33 is a graph showing the experimental results of the second embodiment of the present invention.

Fig. 34 is a schematic diagram showing the overall configuration of a log output system of the third embodiment of the present invention.

Fig. 35 is a block diagram illustrating a functional configuration of a sensor module and a control device according to a third embodiment of the present invention.

Fig. 36 is a flowchart illustrating a log output process according to the third embodiment of the present invention.

Fig. 37 is a diagram illustrating a log output result of the third embodiment of the present invention.

Description of the symbols

2 a: detection surface, 4: a fan, 6: control device, 10: sensor module, 12: log output device, 20: sensor chip, 21: humidity detection unit, 22: temperature detection unit, 23: heating section, 30: ASIC chip, 31: moisture measurement processing unit, 32: temperature measurement processing unit, 33: heating control unit, 40: molding resin, 50: opening, 51: effective opening portion, 63: adhering moisture determination unit, 64: adhering moisture removal control unit, 65: data communication unit, 80: humidity detection capacitor, 81: reference capacitor, 82: reference electrode, 83: lower electrode, 84: upper electrode, 86: moisture-sensitive film, 87: protective coating film, 106 n: type diffusion layer, 200: water repellent film, 300: and (4) a log output system.

Detailed Description

(first embodiment)

The mode for carrying out the present invention will be described below with reference to the accompanying drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant description may be omitted. Further, in the present disclosure, humidity when only referred to as humidity refers to relative humidity.

[ Overall arrangement ]

Next, an example in which the adhering moisture detection device of the present invention is applied to a refrigerator having a vegetable compartment as an example of an electric apparatus will be described.

Fig. 1 is a schematic view showing an overall configuration of a refrigerator of an embodiment of the present invention. As shown in fig. 1, the refrigerator 1 has a refrigerating chamber 7 and a vegetable chamber 3. The refrigerator 1 is provided with a cooler, a compressor, and the like, not shown, and cools the refrigerating chamber 7 by heat exchange. The vegetable compartment 3 is cooled by the cold air flowing out from the refrigerating compartment 7. The vegetable compartment 3 is at a higher temperature than the refrigerating compartment 7. For example, the refrigerating chamber 7 is maintained at about 3 ℃ and the vegetable chamber 3 is maintained at about 5 ℃. In addition, the vegetable compartment 3 is maintained at a temperature higher than that of the refrigerating compartment 7 to prevent drying of vegetables.

A fan 4 for introducing dry air into vegetable compartment 3 is connected to vegetable compartment 3. Fan 4 is driven by driver 5 to blow air into vegetable compartment 3.

In addition, a sensor module 10 for measuring the humidity and temperature in the vegetable room 3 is provided in the vegetable room 3. The sensor module 10 and the driver 5 are connected to a control device 6. The control device 6 detects dew condensation on the basis of the measurement value of the sensor module 10, and controls the driver 5 to start the fan 4 on the basis of the detection result of dew condensation. The fan 4 is a dew condensation removing unit that is driven by the driver 5 as a driving unit and removes dew condensation in the vegetable room 3 as a sensor accommodating space portion in which the sensor module 10 is accommodated.

[ arrangement of sensor Module ]

Next, the configuration of the sensor module 10 will be explained.

Fig. 2 is a diagram illustrating a schematic configuration of the sensor module 10 of an embodiment of the present invention. Fig. 2 (a) is a plan view of the sensor module 10 as viewed from above. Fig. 2 (B) is a bottom view of the sensor module 10 as viewed from below. Fig. 2 (C) is a side view of the sensor module 10 viewed from the lateral direction. In addition, fig. 3 is a sectional view schematically showing a section along the line a-a in fig. 2 (a).

In the sensor module 10, the planar shape is substantially a rectangular shape, and one of two opposing sides is parallel to the X direction and the other is parallel to the Y direction. The X-direction and the Y-direction are orthogonal to each other. The sensor module 10 has a thickness in the Z direction orthogonal to the X direction and the Y direction. The planar shape of the sensor module 10 is not limited to a rectangular shape, and may be a circle, an ellipse, a polygon, or the like.

The sensor module 10 has a sensor chip 20 as a first semiconductor chip, an asic (application Specific Integrated circuit) chip 30 as a second semiconductor chip, a mold resin 40, and a plurality of lead terminals 41.

The sensor chip 20 is laminated on the ASIC chip 30 via a first DAF42(Die Attach Film). That is, the sensor chip 20 and the ASIC chip 30 are in a stacked structure.

The sensor chip 20 and the ASIC chip 30 are electrically connected by a plurality of first bonding wires 43. The ASIC chip 30 and the plurality of lead terminals 41 are electrically connected by a plurality of second bonding wires 44.

The sensor chip 20 and the ASIC chip 30, the plurality of first bonding wires 43, the plurality of second bonding wires 44, and the plurality of lead terminals 41, which are thus stacked, are encapsulated by a molding resin 40. This packaging method is called a PLP (plated Lead Package) method.

The second DAF45 used for packaging by the PLP method remains below the ASIC chip 30, and details thereof will be described later. The second DAF45 has the effect of insulating the underside of the ASIC chip 30. Under the sensor module 10, the second DAF45 and the plurality of lead terminals 41 are exposed.

Each lead terminal 41 is formed of nickel or copper. The first DAF42 and the second DAF45 are each formed of an insulating material made of a mixture of a resin, silicon dioxide, or the like. The molding resin 40 is a black resin having light-shielding properties, such as an epoxy resin containing a mixture of carbon black, silica, or the like.

An opening 50 for exposing a part of the sensor chip 20 from the mold resin 40 is formed on the upper surface side of the sensor module 10. The opening 50 has, for example, a tapered wall portion, and the opening area gradually decreases as it goes downward. Of the openings 50, the lowermost end portion that actually exposes the sensor chip 20 is referred to as an effective opening 51.

When the opening 50 is formed, the sensor chip 20 is pressed against a mold and sealed with the mold resin 40. At this time, the die may be broken due to the pressing force applied to the sensor chip 20 and the ASIC chip 30. In order to prevent the occurrence of the breakage, the thickness T1 of the sensor chip 20 and the thickness T2 of the ASIC chip 30 are preferably 200 μm or more, respectively.

Fig. 4 is a plan view of the sensor module 10 in a state where the molding resin 40 is removed. As shown in fig. 4, the planar shapes of the sensor chip 20 and the ASIC chip 30 are each substantially rectangular in shape, having two sides parallel to the X direction and two sides parallel to the Y direction. The sensor chip 20 is smaller than the ASIC chip 30, and is laminated on the surface of the ASIC chip 30 via the first DAF 42.

The sensor chip 20 is provided with a humidity detection unit 21, a temperature detection unit 22, and a heating unit 23 in a region exposed by the effective opening 51. The heating unit 23 is formed below the humidity detection unit 21 so as to cover the formation area of the humidity detection unit 21. That is, the heating unit 23 has a larger area than the humidity detection unit 21. In this way, the mold resin 40 as the package member encapsulates the sensor chip 20 and the like in a state where the humidity detection portion 21 and the temperature detection portion 22 are exposed.

Further, a plurality of bonding pads (hereinafter, simply referred to as bonding pads) 24 are formed at the end portion of the sensor chip 20. In the present embodiment, 6 pads 24 are formed. The bonding pad 24 is formed of, for example, aluminum or aluminum silicon alloy (AlSi).

The ASIC chip 30 is a semiconductor chip for signal processing and control, and is formed with a humidity measurement processing unit 31, a temperature measurement processing unit 32, and a heating control unit 33 (both see fig. 13), which will be described later.

Further, a plurality of first pads 35 and a plurality of second pads 36 are provided in a region not covered by the sensor chip 20 in the surface of the ASIC chip 30. The first pad 35 and the second pad 36 are formed of, for example, aluminum or aluminum silicon alloy (AlSi).

The first pads 35 are connected to the corresponding pads 24 of the sensor chip 20 via first bonding wires 43. The second pads 36 are connected to the corresponding lead terminals 41 via second bonding wires 44. The lead terminals 41 are disposed around the ASIC chip 30.

At the time of manufacturing, the mounting position of the ASIC chip 30 is determined with the lead terminals 41 as a reference. The mounting position on the ASIC chip 30 of the sensor chip 20 is determined with reference to either the position of the ASIC chip 30 or the lead terminal 41. The opening 50 is formed by a transfer molding method using a mold, and the position of the mold is determined with the lead terminal 41 as a reference.

Reference numeral 25 shown in fig. 4 denotes an allowable formation region of the humidity detection unit 21 and the temperature detection unit 22 on the sensor chip 20. During mounting, the allowable forming region 25 is disposed in the forming region of the opening 50 so as to be surely exposed from the opening 50 even when the ASIC chip 30, the sensor chip 20, and the mold are displaced to the maximum extent. If the humidity detection unit 21 and the temperature detection unit 22 are formed in the formation allowable area 25, the humidity detection unit and the temperature detection unit are reliably exposed from the opening 50 despite the positional deviation.

[ arrangement of sensor chip ]

Next, the arrangement of the sensor chip 20 will be explained.

Fig. 5 is a schematic plan view showing the configuration of the sensor chip 20. The pad 24 is a terminal for voltage application or potential detection from the outside. In fig. 5, the plurality of pads 24 shown in fig. 4 are illustrated as being divided into pads 24a to 24 f. In addition, when the pads 24a to 24f need not be distinguished, they are referred to only as the pads 24.

The pad 24a serves as a ground electrode terminal (GND) grounded to the ground potential. The pad 24a is electrically connected to each part such as the temperature detection unit 22 and the heating unit 23 via a wiring or a substrate.

The pad 24b is a lower electrode terminal (BOT) electrically connected to the lower electrode 83 of the humidity detection unit 21. The pad 24b is used to supply a driving voltage to the lower electrode 83. The pad 24c is a humidity detection terminal (HMD) electrically connected to the upper electrode 84 of the humidity detection unit 21. The pad 24c is used to acquire a detection signal of relative humidity from the upper electrode 84. The pad 24d is a reference electrode terminal (REF) electrically connected to the reference electrode 82 of the humidity detection unit 21. The pad 24d is used to acquire a reference signal for detecting humidity from the reference electrode 82.

Pad 24e is a temperature detection Terminal (TMP) electrically connected to temperature detection unit 22. The pad 24e is used to acquire a detection signal of the temperature. The pad 24f is a Heating Terminal (HT) electrically connected to the heating portion 23. The pad 24f is used to supply a driving voltage for driving the heating portion 23.

Further, an electrostatic discharge (ESD) protection circuit 60 is connected to each of the pads 24b to 24f other than the pad 24 a. Each ESD protection circuit 60 is connected between each of the pads 24b to 24f as an input terminal or an output terminal and the pad 24a as a ground electrode terminal. In the present embodiment, the ESD protection circuit 60 is formed of one diode 61. The diode 61 has an anode connected to the pad 24a and a cathode connected to any one of the pads 24b to 24 f.

The ESD protection circuit 60 is preferably disposed in the vicinity of the pads 24b to 24f so as to be as far away from the effective opening 51 as possible. Since the ESD protection circuit 60 is covered with the molding resin 40, a phenomenon in which unnecessary electric charges are generated due to a photoelectric effect does not occur.

[ configuration of ESD protection Circuit ]

Next, the configuration of the ESD protection circuit 60 will be explained.

Fig. 6 is a circuit diagram illustrating the configuration of the ESD protection circuit 60. As shown in fig. 6, the diode 61 constituting the ESD protection circuit 60 is formed of, for example, an N-channel MOS (Metal-Oxide-Semiconductor) transistor (hereinafter referred to as an NMOS transistor). Specifically, the diode 61 short-circuits the source, gate, and back gate of the NMOS transistor (so-called diode connection). The short circuit portion serves as an anode. The drain of the NMOS transistor serves as a cathode.

Fig. 7 is a diagram illustrating a layer structure of an NMOS transistor constituting the ESD protection circuit 60. The NMOS transistor has two n-type diffusion layers 71 and 72 constituting a surface layer of a p-type semiconductor substrate 70 of the sensor chip 20, a contact layer 73, and a gate electrode 74. The gate electrode 74 is formed on the surface of the p-type semiconductor substrate 70 via a gate insulating film 75. The gate electrode 74 is disposed between the two n-type diffusion layers 71 and 72.

For example, the n-type diffusion layer 71 serves as a source, and the n-type diffusion layer 72 serves as a drain. The contact layer 73 is a low resistance layer (p-type diffusion layer) for electrical connection to the p-type semiconductor substrate 70 as a back gate. The n-type diffusion layer 71, the gate electrode 74, and the contact layer 73 are connected in common and short-circuited. The short serves as an anode and the n-type diffusion layer 72 serves as a cathode.

The p-type semiconductor substrate 70 is, for example, a p-type silicon substrate. The gate electrode 74 is formed of metal or polysilicon (polysilicon). The gate insulating film 75 is formed of an oxide film such as silicon dioxide, for example.

[ arrangement of humidity detection part ]

Next, the arrangement of the humidity detection unit 21 will be described.

Fig. 8 is a circuit diagram illustrating the configuration of the humidity detection portion 21. As shown in fig. 8, the humidity detection unit 21 includes a humidity detection capacitor 80 and a reference capacitor 81.

One electrode (lower electrode 83) of the humidity detection unit 21 is connected to the pad 24b as a lower electrode terminal. The other electrode (upper electrode 84) of the humidity detection unit 21 is connected to the pad 24c serving as a humidity detection terminal. One electrode of the reference capacitor 81 is common to one electrode (lower electrode 83) of the humidity detection unit 21. The other electrode (reference electrode 82) of the reference capacitor 81 is connected to the pad 24d serving as a reference electrode terminal.

The humidity detection capacitor 80 is provided with a humidity sensing film 86, which will be described later, between the electrodes. The humidity sensing film 86 is made of a polymer material such as polyimide that absorbs moisture in the air and changes the dielectric constant according to the amount of absorbed moisture. Accordingly, the capacitance of the humidity detection capacitor 80 changes in accordance with the amount of moisture absorbed by the moisture-sensitive film 86.

The reference capacitor 81 has a second insulating film 111 (see fig. 10) between electrodes, which will be described later. The second insulating film 111 is formed of an insulating material such as silicon dioxide (SiO2) that does not absorb moisture. Accordingly, the capacitance of the reference capacitor 81 is not changed or is changed only slightly.

Since the moisture amount included in the humidity sensing film 86 corresponds to the humidity around the sensor module 10, the relative humidity can be measured by detecting the difference between the electrostatic capacitance of the humidity detection capacitor 80 and the electrostatic capacitance of the reference capacitor 81. The measurement of the relative humidity is performed by the humidity measurement processing unit 31 (see fig. 13) in the ASIC chip 30 based on the potential of the pad 24c serving as the humidity detection terminal and the potential of the pad 24d serving as the reference electrode terminal.

[ arrangement of temperature detecting section ]

Next, the arrangement of the temperature detection unit 22 will be explained.

Fig. 9 is a circuit diagram illustrating the arrangement of the temperature detection section 22. The temperature detector 22 is a band gap type temperature sensor that detects temperature by using a characteristic that changes electrical characteristics in proportion to a band gap temperature change of a semiconductor. For example, the temperature detection unit 22 includes one or more bipolar transistors having any two of a base, an emitter, and a collector as two terminals. The temperature can be measured by detecting the resistance value between the two terminals.

As shown in fig. 9, in the present embodiment, temperature detecting unit 22 is configured by connecting a plurality of (for example, 8) npn-type bipolar transistors 90, each of which has a base and a collector connected thereto, in parallel. By connecting a plurality of bipolar transistors 90 in parallel in this manner, the junction area of the pn junction is increased, and the ESD resistance is improved.

The emitter of the bipolar transistor 90 is connected to the pad 24a as a ground electrode terminal. The base and collector of bipolar transistor 90 are connected to pad 24e, which is a temperature detection terminal.

The temperature is measured by a temperature measurement processing unit 32 (see fig. 13) in the ASIC chip 30 based on the potential of the pad 24 e.

[ element Structure of sensor chip ]

Next, the element structure of the sensor chip 20 will be explained.

Fig. 10 is a schematic cross-sectional view for explaining the element structure of the sensor chip 20. In fig. 10, the

pads

24a, 24b, 24c, and 24e, the humidity detection unit 21, the temperature detection unit 22, and the heating unit 23 are shown in the same cross section, but this is shown for the purpose of facilitating the understanding of the structure and does not mean that the pads are actually present in the same cross section. Similarly, the cross sections of the humidity detection unit 21, the temperature detection unit 22, and the heating unit 23 are simplified to facilitate understanding of the structure, and the positional relationship and the like of each unit are different from those of the actual unit.

As shown in fig. 10, the sensor chip 20 is formed using the aforementioned p-type semiconductor substrate 70. A first deep n-well 100a and a second deep n-well 100b are formed in the p-type semiconductor substrate 70. A temperature detection unit 22 is formed in the first deep n-well 100 a. A heating portion 23 is formed in the second deep n-well 100 b.

P wells

103a and 103b are formed in the surface layer of the P-type semiconductor substrate 70 where neither of the first deep n well 100a and the second deep n well 100b is formed.

Contact layers

104a and 104b each including a P-type diffusion region are formed on the surface layers of the

P wells

103a and 103 b. The contact layers 104a and 104b are low-resistance layers (p-type diffusion layers) for electrically connecting a predetermined wiring layer formed on the p-type semiconductor substrate 70 and the p-type semiconductor substrate 70.

A P well 101 and an n well 102 are formed in the surface layer of the first deep n well 100 a. An n-type diffusion layer 91 and a P-type diffusion layer 92 are formed on the surface layer of the P-well 101. An n-type diffusion layer 93 is formed on the surface layer of the n-well 102. n-type diffusion layer 91, p-type diffusion layer 92, and n-type diffusion layer 93 constitute npn-type bipolar transistor 90 described above, and function as an emitter, a base, and a collector, respectively.

A P well 105 is formed in the surface layer of the second deep n well 100 b. One or more n-type diffusion layers 106 are formed on the surface of the P-well 105. In this embodiment, a plurality of n-type diffusion layers 106 are formed. For example, each n-type diffusion layer 106 extends in a direction orthogonal to the paper surface and is in a one-dimensional lattice shape as a whole (see fig. 12). The n-type diffusion layer 106 has a predetermined resistance value (for example, a sheet resistance value of about 3 Ω), and functions as a resistor that generates heat by a flow of current. That is, the n-type diffusion layer 106 constitutes the heating portion 23 described above.

Each layer in the p-type semiconductor substrate 70 is formed by a general semiconductor manufacturing process (CMOS process). Accordingly, the n-type diffusion layer 106 as a resistor is formed in the same manufacturing process as the n-type diffusion layers 91 and 93 included in a part of the temperature detection section 22. The n-type diffusion layers 106, 91, 93 are simultaneously formed by an ion implantation process of doping an impurity into the substrate by ion implantation with an n-type impurity (for example, phosphorus). That is, the n-type diffusion layer 106 as a resistor has the same depth from the surface of the p-type semiconductor substrate 70 as the n-type diffusion layers 91 and 93 included in a part of the temperature detection section 22. Note that the depth of the n-type diffusion layer 106 from the surface of the p-type semiconductor substrate 70 to the p-type diffusion layer 9 included in a part of the temperature detection section 22 may be the same.

In addition, instead of the ion implantation process, the n-type diffusion layers 106, 91, and 93 may be formed by a thermal diffusion process in which impurities are doped by a thermal treatment.

The n-type diffusion layers 71 and 72 of the ESD protection circuit 60 are also formed by the same manufacturing process (ion implantation process or thermal diffusion process) as the n-type diffusion layers 106, 91, and 93. The contact layer 73 is formed by the same manufacturing process (ion implantation process or thermal diffusion process) as the p-type diffusion layer 92, the

contact layers

104a and 104b, and the like.

Since other layers in the p-type semiconductor substrate 70 mainly serve as contact layers, description is omitted.

A first insulating film 110, a second insulating film 111, and a third insulating film 112 are stacked in this order on the surface of the p-type semiconductor substrate 70. These insulating films are formed of an insulating material such as silicon oxide (SiO2) or silicon nitride (SiN).

A first wiring layer 120 is formed on the first insulating film 110. A second wiring layer 121 is formed on the second insulating film 111. The second insulating film 111 covers the first wiring layer 120. The third insulating film 112 covers the second wiring layer 121. The first wiring layer 120 and the second wiring layer 121 are formed of a conductive material such as aluminum.

A first plug layer 122 having a plurality of first plugs for connecting the first wiring layer 120 to the p-type semiconductor substrate 70 is formed in the first insulating film 110. A second plug layer 123 having a plurality of second plugs for connecting the first wiring layer 120 and the second wiring layer 121 is formed in the second insulating film 111. The first plug layer 122 and the second plug layer 123 are formed of a conductive material such as tungsten.

For example, the wiring 94 for connecting the base and the collector of the bipolar transistor 90 is formed by the first wiring layer 120, and is connected to the p-type diffusion layer 92 and the n-type diffusion layer 93 via the first plug layer 122. The wiring 94 is connected to the pad 24e serving as a temperature detection terminal via the second plug layer 123 and the second wiring layer 121. Further, n-type diffusion layer 91, which is an emitter of bipolar transistor 90, is connected to pad 24a, which is a ground electrode terminal, via first plug layer 122, first wiring layer 120, and second wiring layer 121.

The wiring 107 for grounding one end of the heating portion 23 to the ground potential is formed of the first wiring layer 120, and is connected to the n-type diffusion layer 106 and the contact layer 104b via the first plug layer 122. Further, the wiring 108 for connecting the other end of the heating portion 23 to the pad 24f as a heating terminal is connected to the n-type diffusion layer 106 via the first plug layer 122, and is connected to the pad 24f via the second plug layer 123 and the second wiring layer 121.

The reference electrode 82 of the reference capacitor 81 is formed of the first wiring layer 120, and is connected to the pad 24d (not shown in fig. 10) serving as a reference electrode terminal via the second plug layer 123 and the second wiring layer 121.

The lower electrode 83 of the humidity detection capacitor 80 is formed by the second wiring layer 121, and is connected to the pad 24b serving as the lower electrode terminal. The second wiring layer 121 forms a wiring 85 for connecting the upper electrode 84 of the humidity detection capacitor 80 to the pad 24c serving as a humidity detection terminal. The lower electrode 83 is disposed at a position facing the reference electrode 82 via the second insulating film 111.

The pads 24a to 24f are formed of a conductive material such as aluminum on the third insulating film 112, penetrate the third insulating film 112, and are connected to the second wiring layer 121.

The humidity sensing film 86 is formed on the third insulating film 112. The humidity sensitive film 86 has a thickness of 0.5 to 1.5 μm and is formed of a polymer material that can easily adsorb or desorb water molecules depending on humidity. The humidity sensitive film 86 is, for example, a polyimide film having a thickness of 1 μm. The polymer material forming the humidity sensitive film 86 is not limited to polyimide, and may be cellulose, polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), or the like.

The humidity sensitive film 86 has a flat upper surface, and a flat upper electrode 84 is formed on the upper surface. The upper electrode 84 is formed at a position facing the lower electrode 83 via a humidity sensitive film 86. A part of the upper electrode 84 is connected to the wiring 85. The upper electrode 84 is a conductive film formed of, for example, aluminum having a thickness of 200 nm. In addition, a plurality of openings 84a are formed in the upper electrode 84 to efficiently take water molecules in the air into the humidity sensing film 86.

A protective coating film 87 is provided on the humidity sensitive film 86 so as to cover the upper electrode 84. The protective coating film 87 is formed of a polymer material, for example, the same material as the humidity sensitive film 86. The thickness of the protective coating film 87 is, for example, 0.5 to 10 μm.

Openings for exposing the pads 24a to 24f are formed in the humidity sensitive film 86 and the protective coating film 87.

Thus, the lower electrode 83 and the upper electrode 84 constitute a humidity detection capacitor 80 having parallel plates. The lower electrode 83 and the reference electrode 82 constitute a reference capacitor 81 of a parallel plate. The humidity detection capacitor 80 and the reference capacitor 81 are disposed above the heating unit 23.

Accordingly, the heater 23 generates heat, thereby heating the humidity sensitive film 86 between the lower electrode 83 and the upper electrode 84. As a result, the humidity sensitive film 86 absorbs water molecules in an amount corresponding to the humidity by the temperature rise due to heating, and thus the dielectric constant changes, and the capacitance of the humidity detection capacitor 80 decreases. The temperature detection unit 22 detects a temperature increase caused by the heating unit 23.

Fig. 11 is a plan view illustrating the shapes of the lower electrode 83 and the upper electrode 84. As shown in fig. 11, the lower electrode 83 and the upper electrode 84 are both rectangular in shape. The upper electrode 84 is formed so as to cover the lower electrode 83.

The openings 84a are preferably as small as possible, and the smaller the openings, the more the leakage of the electric field into the air can be prevented. Actually, a plurality of openings 84a are formed. The opening 84a is not limited to a square shape, and may be an elongated strip or a circle. The openings 84a may be arranged in a staggered manner. Preferably, the openings 84a are circular and are arranged in a staggered pattern.

Although not shown in fig. 11, a rectangular reference electrode 82 is formed below the lower electrode 83.

Fig. 12 is a plan view illustrating the shape of the n-type diffusion layer 106 constituting the heating portion 23. As shown in fig. 12, the n-type diffusion layer 106 is in a one-dimensional lattice shape in which a plurality of elongated stripe-shaped regions are arranged in parallel. One end of the one-dimensional lattice-shaped n-type diffusion layer 106 is connected to the wiring 107, and the other end is connected to the wiring 108. The heating unit 23 is located below the temperature detection unit 22 so as to cover the entire temperature detection unit 22.

[ functional Structure of ASIC chip ]

Next, a functional unit disposed in the ASIC chip 30 will be described.

Fig. 13 is a block diagram illustrating a functional structure of the ASIC chip 30. As shown in fig. 13, the ASIC chip 30 is provided with a humidity measurement processing unit 31, a temperature measurement processing unit 32, and a heating control unit 33.

The humidity measurement processing unit 31 applies a predetermined drive voltage to the pad 24b as the lower electrode terminal, and detects the potential of the pad 24c as the humidity detection terminal and the potential of the pad 24d as the reference electrode terminal. Then, the humidity measurement processing unit 31 calculates the relative humidity (% RH) based on the potential difference between the two.

The temperature measurement processing portion 32 detects the potential of the pad 24e as a temperature detection terminal, and calculates the temperature corresponding to the detected potential.

The heating control unit 33 applies a predetermined drive voltage to the pad 24f serving as the heating terminal, and causes a current (for example, about 10 mA) to flow to the heating unit 23 to generate heat. The heating control unit 33 controls the amount of heat generation by controlling the voltage applied to the pad 24 f.

[ functional Structure of control device ]

Fig. 13 shows a functional configuration of the control device 6. The controller 6 is provided with an adhering moisture determination unit 63 and an adhering moisture removal control unit 64. For example, the control device 6 includes an arithmetic device such as a microcomputer or a CPU (Central Processing Unit) and a storage device such as a RAM (Random Access Memory) or a ROM (read only Memory). The control device 6 realizes each function by executing processing based on a program stored in the storage device by the arithmetic device. The control device 6 may be a Field programmable logic circuit such as an FPGA (Field programmable gate Array).

In the present embodiment, the adhering moisture determining unit 63 starts heating by the heating control unit 33 and acquires the measured value of the humidity from the humidity measurement processing unit 31 to determine whether condensation is present. When the adhering moisture determining unit 63 determines that dew condensation has occurred, the adhering moisture removal control unit 64 activates the fan 4 via the driver 5.

In this way, the adhering moisture detection device is constituted by the sensor module 10 as a temperature and humidity detection device and the control device 6. The control device 6 may be incorporated in the sensor module 10.

[ dew condensation determination treatment ]

Next, the condensation determination process performed by the adhering moisture determination section 63 will be described.

Fig. 14 is a flowchart for explaining the exposure determination process. As shown in fig. 14, the adhering moisture determining portion 63 closes the heating portion 23 (step S10), and resets the counter value C to "0" (step S11). Next, the adhering moisture determining unit 63 acquires the humidity H0 of the detection surface measured by the humidity measuring unit 31 (step S12), and determines whether or not the acquired humidity H0 is the first threshold H_TH1This is done (step S13). Step S13 corresponds to determination as to whether or not the temperature has reached the dew point. First threshold value H_TH1For example 100% RH.

When it is determined that humidity H0 is less than first threshold value H_TH1If so (no), the adhering moisture determination unit 63 returns the process to step S11. Thereby, the counter value C is reset (step S11), and the adhering moisture determination unit 63 acquires the humidity H0 measured by the humidity measurement processing unit 31 again (step S12). For example, the measurement and acquisition of the humidity H0 is performed every 30 seconds.

When it is judged in the step S13 that the humidity H0 is the first threshold H_TH1In the above case (yes), the adhering moisture determination unit 63 increments "1" by the counter value C (step S14).

Then, the adhering moisture determination section 63 determines whether or not the counter value C is the threshold value C_TH(step S15). Threshold value C_THFor example, is "10". When it is judged that the counter value C is not the threshold value C_THIf so (no), the adhering moisture determination unit 63 returns the process to step S12, and acquires the humidity H0 measured by the humidity measurement processing unit 31 again (step S12).

When it is determined that the counter value C is the threshold value C_THIf so (yes), the adhering moisture determination unit 63 proceeds to step S16. That is, when humidity H0 is continuously determined to be first threshold H_TH1The above times are threshold C_THIn this case, the adhering moisture determining unit 63 estimates that condensation is likely to occur, and the process proceeds to step S16.

In step S16, the adhering moisture determination unit 63 opens the heating unit 23. When the heating unit 23 generates heat and heating of the detection surface starts, the adhering moisture determination unit 63 acquires the humidity H1 of the detection surface measured by the humidity measurement processing unit 31 (step S17). The measurement and acquisition of the humidity H1 are performed a plurality of times at predetermined time intervals (for example, at intervals of 1 second). The adhering moisture determination unit 63 determines whether or not the acquisition frequency of the humidity H1 has reached a predetermined frequency (for example, 15 times) (step S18), and when the acquisition frequency has reached the predetermined frequency (yes), calculates an average value H of the acquired humidity H1_AVG(step S19).

Then, the adhered water content determination unit 63 determines the average value H_AVGWhether or not it is the second threshold value H_TH2This is done (step S20). Second threshold value H_TH2For example 85% RH. In addition, the second threshold value H_TH2The content is not limited to 85% RH, and may be appropriately changed.

When average value H_AVGLess than a second threshold value H_TH2If the determination is negative, the adhering moisture determination unit 63 determines that condensation does not occur on the detection surface of the sensor module 10 (the surface of the sensor chip 20 in the effective opening 51) (condensation: negative), and returns the process to step S10. At this time, when the fan 4 is not operated, the adhering moisture removal control part 64 stops the fan 4 (step S21). On the other hand, when the average value H is_AVGIs a second threshold value H_TH2In the above case (yes), the adhering moisture determining unit 63 determines that condensation (condensation: positive) has occurred on the detection surface of the sensor module 10, and the process proceeds to step S22.

The determination at step S20 is based on a difference in humidity change of the detection surface when the heating unit 23 heats the sensor chip 20, depending on whether or not dew condensation has occurred, that is, whether or not water droplets (dew condensation water) have adhered to the detection surface. Specifically, when condensation does not occur and water droplets do not adhere to the detection surface, the humidity of the detection surface decreases in a short time and becomes lower than the second threshold value H when heating is started_TH2. On the other hand, condensation occurs on the detection surfaceWhen water droplets are adhered to the detection surface, the humidity does not decrease as long as the water droplets are present on the detection surface even when heating is started, and the humidity of the detection surface is maintained at the second threshold value H for a long time_TH2The above.

In step S22, the adhering moisture determination unit 63 causes the adhering moisture removal control unit 64 to start the operation of the fan 4. By the operation of the fan 4, dry air is introduced into the vegetable room 3 in which the sensor module 10 is located.

Next, the adhering moisture determination unit 63 closes the heating unit 23 while the fan 4 is in operation (step S23), and stops the heating of the sensor chip 20. The adhering moisture determining unit 63 acquires the humidity H2 measured by the humidity measuring unit 31 in the state where the heating is stopped (step S24), and determines whether or not the acquired humidity H2 is less than the first threshold H_TH1(step S25).

When it is determined that humidity H2 is greater than first threshold value H_TH1If so (no), the adhering moisture determination unit 63 returns the process to step S24. As for the metering and acquisition of the humidity H2, for example, it is performed every 30 seconds. When it is determined that humidity H2 is less than first threshold value H_TH1If so (yes), the adhering moisture determination unit 63 proceeds to step S16, and executes the dew condensation determination process of steps S16 to S20 again with the fan 4 being in operation. Further, the first threshold H employed in step S25_TH1The value of (b) may be the value set in step S13 or may be a new value lower than the value set in step S13.

Since the condensation determination process is performed again as a reconfirmation of the disappearance of the water droplets from the detection surface, the determination in step S20 is no (condensation: negative) unless there is any abnormality, and the process proceeds to step S21 to stop the operation of the fan 4.

As described above, by performing the determination based on the difference in the humidity change of the detection surface after the start of heating of the sensor chip 20, dew condensation can be detected quickly and accurately. In addition, the adhering moisture detection device of the present embodiment can be realized in a small size and at low cost because it only needs to include the humidity detection unit, the heating unit, and the control unit, and optical devices such as an optical dew-point meter are not required. In addition, with the adhering moisture detection device of the present embodiment, humidity, temperature, and dew condensation can be detected by one sensor chip 20.

[ test results ]

Next, the experimental results of the humidity change after the start of heating of the sensor chip 20 will be described.

The following experiment results artificially reproduce the environment in the vegetable room 3 by mounting the sensor module 10 on a cooling element and cooling.

Fig. 15 is a graph showing the result of the first experiment in the case where condensation does not occur. Specifically, fig. 15 is a diagram showing changes in humidity and temperature when the heating unit 23 is turned on with the temperature maintained at about 9 ℃ and the humidity maintained at 97 to 98% RH by adjusting the current of the cooling element in a state where the heating unit 23 is turned off.

As shown in fig. 15, when the heating unit 23 is turned on to start heating, it is confirmed that the temperature rises steeply and the humidity drops steeply when condensation does not occur and water droplets do not adhere to the detection surface of the sensor chip 20. In this experiment, the humidity after starting heating (corresponding to the humidity H1) decreased from 70% RH after about 8 seconds. The average value H of the humidity H1 in the 15 second period after the start of heating was confirmed_AVGAbout 76.5% RH, less than the second threshold H_TH2(85％RH)。

Fig. 16 is a graph showing the result of the second experiment in the case where condensation does not occur. The second experiment is different from the first experiment only in that the heating part 23 is opened while the temperature is maintained at about 5 ℃ and the humidity is maintained at about 98.3% RH. In this experiment, the humidity after starting heating (corresponding to the humidity H1) dropped by 70% RH after about 10 seconds. The average value H of the humidity H1 in the 15 second period after the start of heating was confirmed_AVGAbout 78.5% RH, less than the second threshold H_TH2(85％RH)。

Fig. 17 is a graph of experimental results in the case where condensation has occurred. In fig. 17, the humidity indicates a value of 100% RH or more due to the characteristics of the sensor module 10 used in the experiment.

As shown in fig. 17, it was confirmed that when condensation did not occur, a predetermined time was required until the temperature sharply increased and the humidity started to decrease as the heating unit 23 was turned on to start heating. Since the water droplets are condensed on the detection surface of the sensor chip 20 before the start of heating, a predetermined time is required until the water droplets disappear even when the heating is started, and the high humidity state is maintained for the predetermined time.

In this experiment, it took about 90 seconds for the humidity to start to decrease after the start of heating. The average value H of the humidity H1 in the 15 second period after the start of heating was confirmed_AVGAbout 103.5% RH, the above-mentioned second threshold value H_TH2(85% RH) or more.

In addition, it was confirmed that the water droplets completely disappeared after the humidity was decreased to about 70% RH.

[ modified examples ]

Various modifications of the above embodiment will be described below.

In the above embodiment, the preliminary pre-determination process (steps S10 to S15) is performed before the dew condensation determination process (steps S16 to S20) in order to detect whether or not dew condensation is likely to occur, but this pre-determination process is not essential.

In the above embodiment, after the dew condensation is determined to be positive, the dew condensation removal determination process (steps S23 to S25) is performed to confirm the fact that the dew condensation is removed in the state where the fan 4 is operated, but this dew condensation removal determination process is not essential.

< condensation determination processing >

In the above embodiment, after the heating by the heating unit 23 is started, a plurality of measured values of the humidity H1 are acquired, and the average value H of the plurality of measured values is based on_AVGThe presence or absence of dew condensation is judged, but the average value H_AVGThe calculation of (a) is not necessary. For example, the measured value of the humidity H1 after a predetermined time after the start of heating may be used together with the second threshold value H_TH2The presence or absence of condensation is determined by comparison.

The presence or absence of condensation may be determined based on the difference in the rate of change of the humidity H1 after the start of heating. For example, the humidity H1 is acquired once every time Δ t with respect to the humidity H1 after the start of heating, the difference Δ H between the humidity H1(t) at a certain time t after the start of heating and the humidity H1(t + Δ t) after the duration Δ t is obtained (H1 (t + Δ t) -H1(t)), and the presence or absence of dew condensation is determined based on the number of times when the difference Δ H is continuously equal to or greater than the reference value Hs.

Fig. 18 and 19 are diagrams illustrating a relationship between the difference Δ H in humidity after the start of heating and time. Fig. 18(a) shows a case where condensation does not occur. Fig. 18(B) shows a case where mist condensation occurs. Fig. 19 shows the case where condensation occurs in which water droplets condense. In fig. 18 and 19, time Δ t is set to 1 second, and reference value Hs is set to "-1% RH".

As shown in fig. 18(a), when condensation does not occur, since the humidity H1 drops rapidly after the start of heating, the number of times the difference Δ H between the humidity obtained last time and the humidity obtained last time becomes equal to or greater than the reference value Hs is small. In the example shown in fig. 18(a), the number of times is two.

On the other hand, as shown in fig. 18B, when dew condensation (fogging) occurs, the rate of decrease in the humidity H1 after the start of heating becomes gentle, and the number of times the difference Δ H continuously becomes equal to or greater than the reference value Hs increases. In the example shown in fig. 18(a), the number of times is 4. As shown in fig. 19, when dew condensation (condensation) occurs, the rate of decrease in the humidity H1 after the start of heating becomes more gradual, and the difference Δ H is continuously increased more than the reference value Hs.

Accordingly, in the example shown in fig. 18 and 19, after the heating is started, whether or not the dew condensation has occurred can be determined by determining whether or not the number of times the difference Δ H in humidity is continuously equal to or greater than the reference value Hs is equal to or greater than 3 times. The reference number of determinations is not limited to three, and may be changed as appropriate. After the start of heating, the amount of water droplets (dew condensation water) adhering to the detection surface can be estimated based on the number of times that the humidity difference Δ H is continuously equal to or greater than the reference value Hs.

< preliminary judgment processing >

In the above embodiment, the first threshold value H is set in the preliminary determination process for determining whether or not the dew point is reached_TH1The value was set to a fixed value (100% RH), but determination was consideredThe possibility of temperature fluctuation in the middle temperature is preferably changed by changing the first threshold H according to the temperature measured by the temperature measurement processing unit 32_TH1. First threshold value H used in dew condensation removal determination processing_TH1The same is true.

Specifically, for example, when the pre-determination process is performed in an N ° c environment, the adhering moisture determination unit 63 stores data indicating the relationship between the humidity and the temperature corresponding to the N ° c dew point, and sets the humidity corresponding to the temperature measured by the temperature measurement processing unit 32 as the first threshold H_TH1。

The dew point is a temperature at which the amount of water vapor in the atmosphere is equivalent to the amount of saturated water vapor (a temperature at which the relative humidity is 100 RH%). Dew point at N ℃ means a dew point of N DEG C

Fig. 20 is a graph illustrating the relationship of humidity to temperature corresponding to a dew point of N ℃. For example, when the temperature is 10 ℃, the humidity corresponding to a dew point of 5 ℃ is 71% RH, thus setting the first threshold value H_TH1It is sufficient to set the RH at 71%.

The data indicating the relationship between humidity and temperature corresponding to the dew point of N ℃ can be calculated based on the following formula (1) for obtaining the saturated water vapor pressure E (unit: hPa).

E＝(exp(-6096.9385×(T+273.15)^-1+21.2409642-2.711193×10^-2×(T+273.15)

+1.673952×10^-5×(T+273.15)²+2.433502×ln(T+273.15)))/100··· (1)

This formula (1) is called the formula of Santago (SONNTAG). Here, T denotes the celsius を table す.

For example, when T ═ 5 ℃, it is calculated as E ═ 8.72 hPa. Further, when T is 25 ℃, it is calculated as E31.67 hPa. Thus, when the temperature T is 25 ℃, the humidity corresponding to a dew point of 5 ℃ is calculated to be 8.72/31.67 × 100 — 27.53% RH.

< dew condensation removal determination processing >

Next, a modified example of the dew condensation removal determination process will be described.

Fig. 21 is a flowchart for explaining the dew condensation determination process having the dew condensation removal determination process according to the present modification. The flowchart shown in fig. 21 differs from the flowchart shown in fig. 14 only in that steps S30 to S33 are applied instead of steps S22 to S25.

In the present modification, when the dew condensation is determined to be positive and the adhering moisture removal control unit 64 is caused to start the operation of the fan 4 (step S22), the adhering moisture determination unit 63 acquires the humidity H2 measured by the humidity measurement processing unit 31 while keeping the heating unit 23 open without closing (step S30). The adhering moisture determination unit 63 acquires the temperature T measured by the temperature measurement processing unit 32 (step S31).

Next, the adhering moisture determining portion 63 calculates a dew point Td based on the acquired humidity H2 and temperature T (step S32). The dew point Td is calculated using data indicating the relationship between the temperature and the saturated water vapor pressure, data indicating the relationship between the saturated water vapor pressure and the temperature, or the like.

Then, the adhering moisture determination unit 63 compares the calculated dew point Td with the reference temperature Ts (step S33), determines that dew condensation is not removed when the dew point Td is equal to or higher than the reference temperature Ts (determination is no), and returns the process to step S30. On the other hand, when the dew point Td is lower than the reference temperature Ts (yes), it is determined that dew condensation is removed, the process proceeds to step S21, and the adhered moisture removal control unit 64 stops the operation of the fan 4. The reference temperature Ts is set to 5 ℃.

In this way, the determination speed is increased compared to the case where the determination is made based on the dew point in the state where the heating unit 23 is turned on, and the operation of the fan 4 can be stopped in a short time. This is because the water droplets adhering to the detection surface of the sensor chip 20 disappear in a shorter time than the determination performed while the heating portion 23 is kept open, and the determination process can be performed in a state where no water droplets are present on the detection surface.

< condensation water amount estimation processing >

Next, a process of estimating the amount of water droplets (dew condensation water) adhering to the detection surface of the sensor chip 20 will be described.

Fig. 22 is a diagram illustrating changes in humidity and temperature when heating is started in a mist-like condensation environment. More specifically, fig. 22 shows changes in humidity and temperature when heating is stopped in a state where heating is performed by the heating unit 23, mist condensation occurs on the detection surface of the sensor chip 20, and then heating is resumed.

The amount of condensation water can be estimated by comparing the amount of change in temperature after the start of heating in the case where condensation does not occur with the amount of change in temperature before and after the start of heating in the case where condensation does not occur.

Fig. 23 is a diagram illustrating the amount of change in temperature of the sensor chip 20 when heating is started in an environment where condensation does not occur. In the example shown in fig. 23, the temperature change amount Δ T is about 7.6 ℃.

On the other hand, as shown in fig. 22, in an environment where mist condensation occurs, the temperature T (0) before the start of heating is about 6.1 ℃, the temperature T (T) 10 seconds after the start of heating is about 13.3 ℃, and the temperature change amount (T) — T (0)) is about 7.2 ℃. Here, t (t) represents the temperature of the sensor chip 20 after a predetermined time t from the start of heating.

The amount of temperature change in the predetermined period after the start of heating depends on the amount of dew condensation water, and the smaller the amount of dew condensation water, the larger the amount of temperature change, and the closer to the above-mentioned amount of temperature change Δ T. Therefore, the dew condensation water amount can be estimated by obtaining a coefficient Y (hereinafter referred to as a temperature change coefficient Y) represented by the following formula (2), for example.

Y＝ΔT/(T(t)-T(0))-1··· (2)

Fig. 24 is a diagram illustrating a relationship between the dew condensation water amount and the temperature change coefficient Y. Fig. 24 shows the results of experiments with different amounts of dew condensation water, and the temperature change coefficient Y was calculated with Δ T of 7.6 ℃. As described above, it can be seen that the amount of dew condensation water decreases as the temperature change coefficient Y approaches 0.

Next, a specific example of the condensation water amount estimation process performed simultaneously with the condensation determination process will be described. Fig. 25 is a flowchart for explaining the dew condensation water amount estimation process executed simultaneously with the dew condensation determination process. In the dew condensation water amount estimation process shown in fig. 25, the dew condensation water amount is estimated using a humidity change coefficient X indicating a rate of decrease in humidity after the start of heating, in addition to the temperature change coefficient Y. Note that, in the flowchart shown in fig. 25, the preliminary determination process and the dew condensation removal determination process described in the above embodiment are omitted.

First, the adhered water determining unit 63 sets the counter value n to "0" in a state where the heating unit 23 is closed (step S40), acquires the humidity H1(n) measured by the humidity measuring unit 31 (step S41), and acquires the temperature t (n) measured by the temperature measuring unit 32 (step S42). The adhering moisture determination unit 63 causes the storage device to store the acquired humidity H1(0) and temperature T (0) as initial values.

Next, the adhering moisture determining unit 63 starts heating by turning on the heating unit 23 (step S43), and increments the counter value n by "1" (step S44). Then, the adhering moisture determining unit 63 acquires the humidity H1(n) measured by the humidity measuring unit 31 (step S45), and acquires the temperature t (n) measured by the temperature measuring unit 32 (step S46). The adhering moisture determination unit 63 causes the storage device to store the acquired humidity H1(n) and temperature t (n).

Then, the adhering moisture determining section 63 determines whether or not the counter value N is the maximum value N_max(step S47). Maximum value N_maxFor example, "15". When it is determined that the counter value N is not the maximum value N_maxIf so (no), the adhering moisture determination unit 63 returns the process to step S44, increments the counter value, and acquires the humidity H1(n) and the temperature t (n) again. Further, acquisition of the humidity H1(n) and the temperature t (n) is performed, for example, every 1 second.

When it is determined that the counter value N is the maximum value N_maxIf the humidity is determined to be "H", the adhered moisture determination unit 63 performs the average value H based on the humidity H1(n) stored in the storage device_AVGIs calculated (step S48). Average value H_AVGThe calculation of (2) is performed based on the following formula (3).

H_AVG＝(H1(1)+H1(2)+···+H1(N_max))/N_max··· (3)

Next, the adhering moisture determination section 63 calculates the humidity change coefficient X based on the humidity H1(n) stored in the storage device (step S49). The humidity change coefficient X indicates the number of times the difference Δ H in humidity after the start of heating is continuously equal to or greater than the reference value Hs. The calculation process of the humidity change coefficient X will be described later.

Next, the adhering moisture determination unit 63 calculates the temperature change coefficient Y based on the temperature T (n) stored in the storage device and the temperature change amount Δ T stored in the storage device in advance (step S50). The calculation process of the temperature change coefficient Y will be described later.

Next, as in the above embodiment, the adhering moisture determination section 63 determines the average value H_AVGWhether or not it is the second threshold value H_TH2This is done (step S51). When average value H_AVGLess than a second threshold value H_TH2If the determination is negative, the adhered water content determination unit 63 determines that condensation is not occurring (condensation: negative). On the other hand, when the average value H is_AVGIs a second threshold value H_TH2In the above case (yes), the adhering moisture determining unit 63 determines that condensation has occurred (condensation: positive), and the process proceeds to step S52.

In step S52, the adhering moisture determination unit 63 determines the amount of dew condensation water on the detection surface using the humidity change coefficient X and the temperature change coefficient Y.

Fig. 26 is a flowchart illustrating a calculation process of the humidity change coefficient X. When the humidity change coefficient X is calculated in step S49, the adhering moisture determination unit 63 first sets the counter value X and the counter value n to "0", respectively (steps S60 and S61).

Next, the adhering moisture determining portion 63 calculates the difference Δ H based on the humidity H1(n) stored in the storage device (step S62). The difference Δ H is represented by the following formula (4).

ΔH＝H1(n+1)-H1(n)··· (4)

The adhering moisture determination unit 63 determines whether or not the calculated difference Δ H is equal to or greater than a reference value Hs (step S63). When it is determined that the difference Δ H is equal to or greater than the reference value Hs (yes), the adhering moisture determination unit 63 adds "1" to each of the counter value X and the counter value N (steps S64 and S65), and determines whether or not the counter value N is the maximum value N_max. When it is determined that the counter value N is not the maximum value N_maxIf so (no), the adhering moisture determination unit 63 returns the process to step S62, and calculates the difference Δ H again.

On the other hand, when it is determined that the counter value N is the maximum value N_maxThen, the adhering moisture determination unit 63 sets the counter value X (═ N)_max) Recorded in the storage device, and the process is terminated. When it is determined in step S63 that the difference Δ H is smaller than the reference value Hs (no), the adhering moisture determination unit 63 records the counter value X at that point in time in the storage device, and ends the process.

In this way, the counter value X recorded in the storage device is the humidity change coefficient X indicating the number of times the difference Δ H is continuously equal to or greater than the reference value Hs.

Fig. 27 is a flowchart illustrating a process of calculating the temperature change coefficient Y. When the temperature change coefficient Y is calculated in step S50, the adhering moisture determination section 63 first reads the initial value and the stored temperature T (0) from the storage device (step S70). Next, the adhering moisture determining portion 63 reads the temperature H1(t) after a predetermined time t from the start of the heater in step S43 (step S71). For example, the adhering moisture determination unit 63 reads the temperature H1(10) 10 seconds after the start of heating as the temperature H1(t) with n being 10.

The adhering moisture determination unit 63 reads the temperature change amount Δ T in the case where condensation does not occur, which is stored in advance in the storage device (step S72). Then, the adhering moisture determination section 63 calculates the temperature change coefficient Y based on the above expression (2).

Fig. 28 is a flowchart illustrating the process of determining the amount of dew condensation water. First, the adhering moisture determining unit 63 determines whether the humidity change coefficient X is the maximum value N_max(step S80). When it is judged that the humidity change coefficient X is the maximum value N_maxIf the temperature change coefficient Y is equal to or greater than the threshold value Y, the adhered water content determination unit 63 determines whether or not the temperature change coefficient Y is equal to or greater than the threshold value Y_THThis is done (step S81). Threshold value Y_THFor example, is "0.08".

When the temperature variation coefficient Y is the threshold value Y_THWhen the temperature is above the threshold value Y (yes), the adhering moisture determination unit 63 determines that the dew condensation water amount is "large" (step S82), and if the temperature change coefficient Y is smaller than the threshold value Y_THIf so (no), the adhering moisture determination unit 63 determines that the dew condensation water amount is "medium" (step S83).

When in step S8It is judged that the humidity change coefficient X is not the maximum value N at 0_maxIf the temperature change coefficient Y is equal to or greater than the threshold value Y (no), the adhered water content determination unit 63 determines whether or not the temperature change coefficient Y is equal to or greater than the threshold value Y_THThis is done (step S84). As with step S81, threshold Y_THFor example, is "0.08".

When the temperature variation coefficient Y is less than the threshold value Y_THIf the temperature change coefficient Y is equal to the threshold value Y (no), the adhering moisture determination unit 63 determines that the dew condensation water amount is "small (mist)" (step S85)_THIn this case (yes), the adhering moisture determination unit 63 determines "error" (step S86).

That is, the larger the number of times the difference Δ H is continuously equal to or greater than the reference value Hs, and the smaller the temperature change amount (T) -T (0)), the larger the amount of dew condensation water estimated by the adhering moisture determining section 63.

If the determination is made only by the humidity change coefficient X, the dew condensation water amount cannot be estimated in detail, but according to the present determination method, the determination is made by the temperature change coefficient Y in addition to the humidity change coefficient X, and therefore the dew condensation water amount can be pushed in more detail. The adhering moisture determination unit 63 may perform the determination only by the humidity change coefficient X without using the temperature change coefficient Y. The present disclosure does not exclude a determination method using only the humidity change coefficient X.

The order of the processing shown in the flowcharts can be changed as long as no contradiction occurs.

< preliminary judgment processing >

Next, a modification of the preliminary determination process will be described. Fig. 29 is a flowchart illustrating a modification of the pre-determination process. In the present modification, a plurality of steps S90 to S95 are added to the flowchart shown in fig. 14 or 21.

As shown in fig. 29, in the present modification, after step S10, the adhering moisture determination unit 63 sets the counter value q to "0" (step S90). Then, after acquiring the humidity H0 in step S12, the adhering moisture determination unit 63 acquires the temperature T0 measured by the temperature measurement processing unit 32 (step S91).

Next, the adhering moisture determining section 63 calculates a dew point td (q) based on the acquired humidity H0 and temperature T0 (step S92). The adhering moisture determination unit 63 causes the storage device to store the calculated dew point td (q). The calculation process of the dew point td (q) is the same as the calculation process performed in step S32 shown in fig. 21. The adhering moisture determination section 63 calculates a difference Δ Td using the dew points Td (q) and Td (q-1) stored in the storage device (step S93). The difference Δ Td is expressed by the following equation (5).

ΔTd＝Td(q)-Td(q-1)··· (5)

Here, Td (q-1) is the dew point calculated last time in step S92. Further, when there is no dew point calculated last time, steps S93, S94 may be skipped and the process proceeds to step S95. Further, when there is no dew point calculated last time, an initial value stored in advance in the storage device may be used.

Next, the adhering moisture determination section 63 compares the calculated difference Δ Td with a threshold value T_THThe comparison is made (step S94) when the difference Δ Td is smaller than the threshold T_THIf so (no), the adhering moisture determination unit 63 increments "1" by the counter value q (step S95), and the process proceeds to step S13. On the other hand, when the difference Δ Td is the threshold value T_THIn the above case, the adhering moisture determining unit 63 estimates that condensation is likely to occur, and the process proceeds to step S16. Here, the threshold value T_THFor example, 1.5 ℃. Just a threshold value T_THIf the value is too small, the possibility of erroneous determination increases, whereas if the value is too large, determination cannot be performed, and therefore, it is preferable to set an appropriate value according to the application. Further, the threshold T is set with the assumed ambient temperature as a parameter_THIt is also preferable.

By adding the condensation estimation process based on the change in the dew point to the pre-determination process in this manner, condensation can be estimated even when a rapid change in humidity occurs at the same temperature. This makes it possible to quickly detect adhesion of water droplets such as spray, detection of water immersion, and the like.

< other modification >

Since the sensor module 10 has the concave opening 50 formed in the mold resin 40 on the detection surface, dew condensation is likely to accumulate on the detection surface, and the occurrence of dew condensation can be detected early.

In order to detect the occurrence of dew condensation early, as shown in fig. 30, a water repellent film 200 having water repellency may be formed around the opening 50 on the detection surface 2a of the sensor chip 20. The water repellent film 200 is preferably formed outside the upper electrode 84. The water repellent film 200 may be a film made of a material having a higher water repellency than the protective coating film 87. By providing the water repellent film 200 in this manner, dew condensation water is easily concentrated on the detection surface 2a, and thus the detection sensitivity to dew condensation is improved.

In the above embodiment, the reference electrode 82 is disposed above the heating portion 23 in the sensor chip 20, but the reference electrode 82 does not necessarily have to be located above the heating portion 23.

In the above embodiment, the p-type semiconductor substrate 70 is used as the semiconductor substrate for forming the sensor chip 20, but an n-type semiconductor substrate may be used. In this case, the heating portion 23 may be formed of a p-type diffusion layer. That is, the heating portion may be formed of an impurity diffusion layer formed by doping impurities into a surface layer of the semiconductor substrate.

In the above-described embodiment, the temperature detection unit 22 is configured by the npn bipolar transistor 90, but the temperature detection unit 22 may be configured by a pnp bipolar transistor.

In the above-described embodiment, the electrode structure of the humidity detection capacitor 80 provided in the sensor chip 20 is a parallel plate type, but instead, a so-called comb-shaped electrode structure may be adopted. The sensor chip may be a temperature/humidity sensor having a heating portion (heater).

In the present disclosure, the positional relationship between two elements expressed by the terms "cover" or "upper" includes a case where the first element is provided on the surface of the second element indirectly via another element and a case where the first element is provided directly on the surface of the second element.

In the above embodiment, the dew condensation is removed by the fan, but other dew condensation removing means than the fan, such as a dew condensation removing means for removing dew condensation by rotating the magnetic disk in the hard disk drive, a dew condensation removing means by air blowing, or the like may be employed.

In the above embodiment, the temperature detection unit 22 is mounted on the sensor chip 20, but the temperature detection unit may be mounted on the ASIC chip 30, or a temperature increase caused by the heating unit 23 may be detected by the temperature detection unit mounted on the ASIC chip 30.

(second embodiment)

The second embodiment will be described below with reference to the drawings. The second embodiment is different from the first embodiment in that frost formation is detected in addition to detection of dew condensation. In the following description of the second embodiment, points different from those of the first embodiment will be described, and the same reference numerals as those used in the description of the first embodiment will be given to constituent elements having the same functional configurations as those of the first embodiment, and the description thereof will be omitted.

The refrigerator 1 of the present embodiment also has a freezing chamber 11. A sensor module 10 is provided on a wall surface in the chamber of the freezing chamber 11.

The refrigerator 1 according to the present embodiment detects dew condensation occurring in the vegetable compartment 3 and also detects frost formation occurring in the freezing compartment 11 by using the sensor module 10.

Control device 6 determines whether or not dew condensation has occurred in vegetable compartment 3, and also determines whether or not frost has occurred in freezing compartment 11. Then, when it is determined that frosting has occurred in the freezing chamber 11, the control device 6 controls the driver 5 to activate the heater 8.

The heater 8 is driven by the driver 5, and heats the inside of the freezing chamber 11 to dissolve frost.

The heater 8 functions as an adhering moisture removing portion for removing adhering moisture.

The adhering moisture determination unit 63 of the control device 6 of the present embodiment determines whether condensation or frost formation has occurred. Specifically, the adhering moisture determining section 63 executes an adhering moisture determining process for determining whether or not the adhesion of moisture such as dew condensation or frost formation has occurred, by the same process as the dew condensation determining process shown in fig. 14 or 21.

In the adhering moisture determination process, the adhering moisture determination unit 63 determines whether condensation has occurred when the temperature T0, which is the temperature at which the heating unit 23 is in the closed state, is 0 ℃ or higher, and determines whether frost formation has occurred when the temperature T0 is lower than 0 ℃.

When the adhering moisture determining unit 63 determines that condensation has occurred, the adhering moisture removal control unit 64 of the control device 6 of the present embodiment controls the actuator 5 to start the fan 4, and when it determines that frost has occurred, the adhering moisture removal control unit 64 of the control device 6 of the present embodiment controls the actuator 9 to start the heater 8.

The adhering moisture removal control unit 64 executes an adhering moisture removal determination process for confirming removal of the adhering moisture such as dew condensation and frost formation by the same process as the dew condensation removal determination process shown in fig. 14 or 21.

In the present embodiment, it may be determined whether the temperature has reached the dew point or whether the temperature has reached the frost point in the pre-determination process. In addition, the frost point is a temperature at which frost occurs, and a temperature lower than the dew point is known.

The first threshold H is changed in accordance with the temperature measured by the temperature measurement processing unit 32_TH1It is also preferable. First threshold value H used in determination processing for removing adhered moisture_TH1The same is true.

Specifically, for example, when the pre-determination process is performed in an environment of N ℃, the adhering moisture determination section 63 stores data indicating the relationship between the humidity and the temperature corresponding to the dew point of N ℃ and data indicating the relationship between the humidity and the temperature corresponding to the frost point of N ℃, and sets the humidity corresponding to the temperature measured by the temperature measurement processing section 32 as the first threshold H_TH1. Further, the frost point of N ℃ means that the frost point is N ℃.

In this case, whether to use data corresponding to the N ℃ dew point or data corresponding to the N ℃ frost point may be determined according to the temperature. For example, when the temperature N is 0 or more, data corresponding to the dew point of N ℃ may be used, and when the temperature is less than 0, data corresponding to the frost point of N ℃ may be used.

The data representing the relationship between humidity and temperature corresponding to the frost point of N deg.C can be calculated based on the following formula (6) for finding the saturated water vapor pressure E (unit: hPa) of ice.

E＝(exp(-6024.5282×(T+273.15)^-1+29.32707+1.0613868×10^-2×(T+273.15)

-1.3198825×10^-5×(T+273.15)²-0.49382577×ln(T+273.15)))/100···(6)

The formula (6) is a formula regarding the saturated water vapor pressure of ice in the SONNTAG formula. Here, T represents a temperature in celsius.

Next, a modification of the preliminary determination process will be described. Fig. 32 is a flowchart illustrating a modification of the pre-determination process according to the second embodiment of the present invention. In this modification, steps S96 and S97 for calculating the frost point are added to the flowchart shown in fig. 29.

As shown in fig. 32, in the present modification, the adhering moisture determining section 63 determines whether or not the temperature T0 is 0 ℃. When it is determined that the temperature T0 is 0 ℃ or higher (yes), the adhering moisture determination unit 63 calculates the dew point td (q) (step S92).

When it is determined that the temperature T0 is not equal to or higher than 0 ℃ (no determination), the adhering moisture determination unit 63 calculates the frost point td (q) (step S97). Specifically, the adhering moisture determining section 63 calculates the frost point td (q) using the data indicating the relationship between the humidity and the temperature corresponding to the frost point at N ℃ calculated based on the above formula (6).

In this way, the adhering moisture determining unit 63 of the present modification determines whether or not there is a possibility of condensation or frost formation by a pre-determination process.

Further, the threshold value T compared with the difference value Δ Td in step S94_THThe threshold may be different depending on whether or not the temperature T0 is 0 ℃ or higher, or may be the same threshold regardless of the temperature T0. In addition, the threshold value T_THThe threshold value may be different with a boundary of a temperature other than 0 ℃ at the temperature T0.

[ test results ]

Next, the experimental result of the humidity change after the start of heating of the sensor chip 20 will be described. The following experiment results artificially reproduce the environment in the freezing chamber 11 by mounting the sensor module 10 on a cooling element and cooling.

The experiment was carried out at a temperature of 15 ℃ and a humidity of 35% RH. In addition, the dew point was-0.323 ℃ and the frost point was-0.273 ℃ in this environment.

As shown in fig. 33, it was confirmed that, when cooling by the cooling element was started 50 seconds after the start of the experiment, the temperature was-8 ℃ during the period from the start of the experiment to 200 seconds after the start of the experiment, and frost was generated.

Next, when the heating unit 23 is turned on to start heating 200 seconds after the start of the experiment, there is a time lag of about 20 seconds until the temperature rises steeply and the humidity starts to fall.

Thus, it was confirmed that the frost formation can be detected by utilizing a phenomenon in which the decrease in humidity is delayed when the frost formation occurs.

(third embodiment)

The third embodiment will be described below with reference to the drawings. The third embodiment is different from the first embodiment in that the detection of adhering moisture is continuously performed, and a log of the execution result is output. In the following description of the third embodiment, points different from those of the first embodiment will be described, and the same reference numerals as those used in the description of the first embodiment will be given to constituent elements having the same functional configurations as those of the first embodiment, and the description thereof will be omitted.

The log output system 300 continues to perform the detection of the adhering moisture, and outputs a log of the execution result. For example, the log output system 300 is used to monitor whether moisture adheres to vegetables cultivated in a vinyl house.

Specifically, the log output system 300 includes the sensor module 10, the control device 6, and the log output device 12.

As with the first embodiment, the sensor module 10 of the present embodiment measures humidity and temperature.

As in the first embodiment, the control device 6 of the present embodiment receives the measurement result from the sensor module 10 and determines whether or not the adhesion of moisture has occurred.

The log output device 12 receives the determination result and the measurement data from the control device 6, and outputs log data including the received determination result and the measurement data to an output section such as a display.

The control device 6 of the present embodiment includes an adhering moisture determination unit 63 and a data communication unit 65.

The data communication unit 65 transmits log data including the determination result by the moisture determination unit 63 and the measurement result received from the sensor module 10 to the log output device 12. The data communication unit 65 receives a signal instructing the start or end of the log output process, data indicating the current time, and the like from the log output device 12.

When the data communication section 65 of the control device 6 receives a signal instructing the start of the log output process from the log output device 12, the control device 6 starts the log output process shown in fig. 36.

The adhering moisture determination unit 63 sets the time variable t to "0 second" (step S101). Further, the time variable t is a variable indicating the elapsed time since the initial setting was performed in this step S101.

Then, the adhering moisture determination unit 63 receives the time data indicating the current time from the log output device 12 (step S102).

Next, the adhering moisture determining unit 63 acquires data indicating the temperature and the humidity (step S103). Specifically, the adhering moisture determining section 63 receives data indicating the humidity of the detection surface measured by the humidity measurement processing section 31 and data indicating the temperature measured by the temperature measurement processing section 32.

Next, the adhering moisture determination unit 63 determines whether or not the measurement of step S104 is performed N times (step S104). Here, N is a value indicating a reference number of times set in advance, and is set to 8, for example, in consideration of a measurement environment and the like. If it is determined that the measurement is not performed N times (no), the adhering moisture determination unit 63 waits for 1 second (step S105), and returns to the process of step S103.

When it is determined that N measurements have been performed (yes), the adhering moisture determination unit 63 calculates the average temperature T based on the N measurement results_OFFAVGAnd average humidity H_OFFAVG(step S106).

Next, the adhering moisture determination unit 63 turns on the heating unit 23 (step S107), and waits for 1 second (step S108). Further, by waiting for 1 second after the heating portion 23 is turned on, the temperature rise of the sensor chip 20 is stabilized. Since there is a possibility that the detection result of the temperature or humidity is inaccurate while the temperature rise of the sensor chip 20 is stable, the detection accuracy can be improved by acquiring data after the temperature rise of the sensor chip 20 is stable.

Next, the adhering moisture determination section 63 acquires data indicating the temperature and the humidity (step S109). The adhering moisture determination section 63 determines whether or not the measurement of step S109 is performed M times (step S110). Here, M is a value indicating a reference number of times set in advance, and is set to 2, for example, in consideration of the measurement environment and the like. If it is determined that the measurement is not performed M times (no), the adhering moisture determination unit 63 returns to the process of step S108.

When it is determined that M measurements have been taken (yes), the adhering moisture determination unit 63 turns off the heating unit 23 (step S111), and calculates the average temperature T based on the M measurement results_ONAVGAnd average humidity H_ONAVG(step S112).

Subsequently, the adhering moisture determining section 63 determines whether or not H is present_OFFAVG＞H_TH3And H is_OFFAVG-H_ONAVG≤H_D(step S113). H_TH3And H_DIs a preset threshold, e.g. set to H_TH3＝90％RH，H_D＝1。

When dew condensation, frost, or the like adheres to the sensor chip 2When moisture is present, the decrease in humidity is delayed, so that H_OFFAVG-H_ONAVGThe value of (c) becomes small. Thus, according to whether H is_OFFAVG-H_ONAVG≤H_DThe determination of (2) can be made as to whether or not moisture adheres to the sensor chip 20.

In addition, since moisture such as condensation or frost is deposited in an environment with high humidity, whether or not H is present depends on whether or not H is present_OFFAVG＞H_TH3The determination of (2) can be assisted in determining whether or not the environment is an environment in which the adhesion of moisture is likely to occur.

When it is judged as H_OFFAVG＞H_TH3And H is_OFFAVG-H_ONAVG≤H_DIf the determination is yes, the adhered water content determination unit 63 sets the value of the determination result to 1 (positive) (step S114). The value 1 (positive) indicates that moisture such as condensation or frost has adhered.

If it is determined not to be H_OFFAVG＞H_TH3And H is_OFFAVG-H_ONAVG≤H_D(H_OFFAVG≤H_TH3Or H_OFFAVG-H_ONAVG＞H_D) If the determination result is negative (no), the value of the determination result is set to 0 (negative) (step S115). 0 (negative) is a value indicating that no moisture such as condensation or frost is deposited.

Next, the data communication unit 65 includes the time data acquired in step S102 and the average temperature T calculated in step S106_OFFAVGAnd average humidity H_OFFAVGAnd the data of the value of the determination result determined in step S114 or step S115 is transmitted to the log output device 12 (step S116).

Then, the adhering moisture determining unit 63 waits until the time variable T becomes T_s(step S117). Here, t_sIs a reference value set in advance, for example, set to 600 seconds in consideration of the measurement environment and the like. In addition, it was confirmed from the results of the experiment that the sensor chip 20 returned to the temperature and humidity of the outside air after about 60 seconds from the closing of the heating unit 23. Thus, t can be adjusted_sSet to about 60 seconds. Further, it may be necessary to detect the adhering moisture in the data communication unit 65, the adhering moisture determination unit 63, or the like during a period of time when T is tsThe operating block is set to sleep and at the beginning T ═ T_sThe power consumption is suppressed by performing the intermittent operation in such a manner that the adhered moisture is detected as being active.

The adhering moisture determination unit 63 determines whether or not a signal indicating the end of the processing is received from the log output device 12 (step S118). Specifically, when the variable t is changed from 0 second to t at the waiting time_sIf a signal indicating the end of the processing is received from the log output device 12 within the period of time (g), the determination result in step S118 is YES.

When it is determined that the signal indicating the end of the process has not been received from the log output device 12 (no determination), the adhering moisture determination unit 63 returns to the process of step S101.

When it is determined that a signal indicating the end of the processing is received from the log output device 12 (yes), the adhering moisture determination unit 63 ends the log output processing.

The log output device 12 displays the log on a display unit such as a display based on the data received from the control device 6.

The table 310 showing the log output result includes "date and time", "temperature", "humidity", and "attached moisture determination result" as items.

The value of the item "date and time" is a value indicated by the time data received from the control device 6. The term "date and time" is a value indicating the measured date and time, and strictly speaking, a value indicating the start time of measurement because the measurement is performed a plurality of times.

The value of the item "temperature" is the average temperature T received from the control device 6_OFFAVGThe value of (c).

The value of the item "humidity" is the average humidity H received from the control device 6_OFFAVGThe value of (c).

The value of the item "adhered moisture determination result" is the value of the determination result received from the control device 6.

According to the log output system 300 of the present embodiment, it is possible to continue outputting whether condensation, frost, or the like has occurred. Thus, the log output system 300 is useful for, for example, confirmation of the result of humidity control in a vinyl house at night.

Although the preferred embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various modifications and substitutions may be made to the above embodiments without departing from the scope of the present invention. In the above-described embodiments, the adhering moisture detection device has been described which detects adhering moisture such as dew condensation occurring in the vegetable compartment of the refrigerator and frost formation occurring in the freezer compartment, but the present invention can detect adhering moisture such as dew condensation and frost formation occurring in various electrical devices such as a hard disk drive, the inside of a projector, the inside of an air conditioner, and a window glass.

Claims

1. An adhering moisture detection device is characterized by comprising:

a sensor chip including a humidity detection portion having a detection surface for detecting humidity and a heating portion for heating the detection surface; and

and an adhering moisture determination unit that determines whether or not there is adhering moisture on the detection surface based on a difference in change in the humidity detected by the humidity detection unit after the heating of the heating unit is started.

2. The adhering moisture detecting device according to claim 1,

the adhering moisture determination unit acquires the humidity detected by the humidity detection unit a plurality of times at a predetermined time interval after the heating unit starts heating, and determines that the adhesion of moisture has occurred when an average value of the acquired plurality of humidities is less than a threshold value.

3. The adhering moisture detecting device according to claim 1,

the adhering moisture determination unit acquires the humidity detected by the humidity detection unit a plurality of times at a predetermined time interval after the heating unit starts heating, and determines that moisture has adhered when the number of times the difference from the humidity acquired last time is continuously equal to or greater than a reference value is equal to or greater than a reference number.

4. The adhering moisture detecting device according to claim 3,

the adhering moisture determination unit estimates the amount of moisture adhering to the detection surface based on the number of times the difference value is continuously equal to or greater than a reference value.

5. The adhering moisture detecting device according to claim 4,

the sensor chip has a temperature detection portion that detects a temperature,

the adhering moisture determination unit estimates the amount of moisture based on the difference value continuously obtained for a number of times equal to or greater than a reference value and a temperature change amount within a predetermined period after the heating unit starts heating.

6. The adhering moisture detection device according to claim 4, comprising:

a semiconductor chip that processes signals from the sensor chip,

the semiconductor chip has a temperature detection unit for detecting temperature,

7. The adhering moisture detecting device according to claim 5 or 6,

the amount of moisture estimated by the adhering moisture determining unit increases as the number of times the difference value is continuously equal to or greater than the reference value increases and as the amount of temperature change decreases.

8. The adhering moisture detecting device according to claim 1,

the sensor chip has a temperature detection portion that detects a temperature,

the adhering moisture determination unit determines whether condensation or frost formation is to be determined based on the temperature.

9. The adhering moisture detecting device according to claim 1,

the sensor chip has a semiconductor substrate with a semiconductor layer,

the heating portion is formed of an impurity diffusion layer in the semiconductor substrate,

the humidity detection unit includes a lower electrode formed above the heating unit via an insulating film, a humidity sensing film covering the lower electrode, and an upper electrode formed on the humidity sensing film.

10. The adhering moisture detecting device according to claim 9,

the impurity diffusion layer is in a one-dimensional lattice shape.

11. An electric apparatus comprising the adhering moisture detection device according to any one of claims 1 to 10, a sensor housing space portion housing the sensor chip, an adhering moisture removal portion, a drive portion driving the adhering moisture removal portion, and a control portion controlling the adhering moisture determination portion and the drive portion,

the control unit drives the adhering moisture removing unit by controlling the driving unit according to the determination result of the adhering moisture determining unit, and removes the adhesion of moisture in the sensor housing space.

12. A log output system is provided with:

a sensor chip including a humidity detection unit having a detection surface for detecting humidity, a temperature detection unit for detecting temperature, and a heating unit for heating the detection surface;

an adhering moisture determination unit that determines whether or not there is adhering moisture on the detection surface based on a difference in change in the humidity detected by the humidity detection unit after the heating unit is started to heat; and

and a data communication unit that outputs the humidity, the temperature, and the result of the determination.

13. A method for detecting adhering moisture, which uses a sensor chip including a humidity detection portion having a detection surface for detecting humidity and a heating portion for heating the detection surface, characterized in that,

after the heating by the heating unit is started, whether or not moisture adheres to the detection surface is determined based on a difference in change in humidity detected by the humidity detection unit.