JP7407621B2 - Detection circuit equipped with heated sensor - Google Patents

Description

The present invention relates to a heating type sensor-equipped detection circuit that has a heater mounted on its main body and detects physical quantities in the atmosphere (for example, humidity, temperature, gas concentration, etc.).

BACKGROUND ART Conventionally, as a sensor for preventing the occurrence of dew condensation, a humidity sensor disclosed in Patent Document 1 listed below, for example, is known. In the humidity sensor of Patent Document 1, a sensor element consisting of a moisture-sensitive film and a humidity sensor electrode is formed on one side of a substrate, and heat is generated in a portion on the other side of the substrate that faces the humidity-sensitive film through the substrate. A heating element electrode is formed at the end of the heating element. The temperature that the heating element reaches is determined in advance, and when the heating element is operated, the humidity sensor is maintained at a constant temperature that is higher than the highest possible dew point in the usage environment.

Further, as another structure for preventing the occurrence of dew condensation, semiconductor devices disclosed in, for example, Patent Document 2 and Patent Document 3 listed below are known. In the semiconductor device of Patent Document 2, a gel-like hygroscopic resin made of silicone filled with a desiccant such as silica gel and a dark pigment is applied dropwise to the entire surface of the semiconductor element mounted on the bottom surface of the package except for the main surface. Further, in the semiconductor device of Patent Document 3, a light-shielding dehumidifying member is provided inside a semiconductor light receiving element having a transparent window.

Japanese Patent Application Publication No. 2002-039983 JP2004-022928A Japanese Patent Application Publication No. 2011-151412

However, in the configuration disclosed in Patent Document 1 mentioned above, it is necessary to form a heating element and a heating element electrode on the substrate separately from the sensor element, which not only increases the number of component parts but also increases the number of components required to separately provide the heating element. The problem is that a large amount of space is required.

Furthermore, the configurations disclosed in Patent Document 2 and Patent Document 3 described above have a problem in that it is difficult to obtain long-term effects due to aging deterioration and the like.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a detection circuit equipped with a heating type sensor that can effectively utilize a heating type sensor to prevent the occurrence of dew condensation on a printed wiring board. The purpose is

In order to achieve the above object, the heating type sensor equipped detection circuit according to claim 1 of the present invention is provided with a heating type sensor mounted detection circuit equipped with a heater and arranged on a printed wiring board, and which has a humidity sensor for detecting humidity in the atmosphere. type sensor,
a monitoring temperature sensor that detects the temperature of the printed wiring board;
A control means for calculating a dew point temperature based on the humidity detected by the humidity sensor and the temperature detected by the monitoring temperature sensor, and controlling the heater so that the temperature of the printed wiring board becomes higher than the dew point temperature. and
The monitoring temperature sensor is arranged on the printed wiring board in a state that is thermally isolated from the heating type sensor .

The heating type sensor mounting detection circuit according to claim 2 of the present invention includes a heating type sensor equipped with a heater and disposed on a printed wiring board, and having a gas sensor that detects the concentration of gas in the atmosphere.
a monitoring temperature sensor that detects the temperature of the printed wiring board;
a monitoring humidity sensor that detects humidity in the atmosphere;
A dew point temperature is calculated based on the temperature detected by the monitoring temperature sensor and the humidity detected by the monitoring humidity sensor, and the heater is controlled so that the temperature of the printed wiring board becomes higher than the dew point temperature. It is characterized by comprising a control means.

The heating type sensor mounting detection circuit according to claim 3 of the present invention includes a heating type sensor mounted with a heater and disposed on a printed wiring board, and having a temperature sensor for detecting the temperature of the printed wiring board ;
A monitoring humidity sensor that detects humidity in the atmosphere ,
A control means for calculating a dew point temperature based on the temperature detected by the temperature sensor and the humidity detected by the monitoring humidity sensor, and controlling the heater so that the temperature of the printed wiring board becomes higher than the dew point temperature. It is characterized by having the following.

The heating-type sensor-equipped detection circuit according to claim 4 of the present invention is the heating-type sensor-equipped detection circuit according to claim 2 , which includes:
The monitoring temperature sensor is arranged on the printed wiring board in a state that is thermally isolated from the heating type sensor.

The heating type sensor mounted detection circuit according to claim 5 of the present invention is the heating type sensor mounted detection circuit according to any one of claims 1 to 4,
Equipped with circuit parts including multiple heat generating parts,
The plurality of heat generating components are arranged on the printed wiring board according to the magnitude of the waste heat of the plurality of heat generating components so that the waste heat of the plurality of heat generating components is evenly conducted to the printed wiring board . It is characterized by being placed.

According to the present invention, it is possible to prevent dew condensation on a printed wiring board by effectively utilizing a heating type sensor equipped with a heater without requiring extra space for separately arranging a heating element as in the past. Can be done.

FIG. 1 is a block configuration diagram of a first embodiment of a heating type sensor mounting detection circuit according to the present invention. FIG. 2 is a block configuration diagram of a second embodiment of a heating type sensor mounting detection circuit according to the present invention. FIG. 3 is a block configuration diagram of a third embodiment of a heating type sensor mounting detection circuit according to the present invention. (a), (b), and (c) are plan views showing an example of the arrangement of heat generating components on a printed wiring board in a heating type sensor mounted detection circuit according to the present invention and a state of heat conduction by waste heat. (a), (b), and (c) are plan views showing other examples of arrangement of heat-generating components on a printed wiring board in a heating type sensor-mounted detection circuit according to the present invention, and the state of heat conduction by waste heat. FIG. 2 is a partial plan view of a printed wiring board showing an example of a state in which a heating sensor and a monitoring temperature sensor are thermally separated in the heating sensor mounting detection circuit according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the attached drawings.

The heating type sensor mounted detection circuit according to the present invention is a circuit that detects physical quantities in the atmosphere (humidity, gas concentration, temperature, etc.), and a heating type sensor with a heater mounted on the main body is arranged on a printed wiring board, It is configured as a MEMS (Micro Electro Mechanical Systems) device that has a function of controlling a heater so that the temperature of the printed wiring board is higher than the dew point temperature. The heating type sensor-equipped detection circuit is used by being housed in the housing of various sensors (humidity sensor, gas sensor, temperature sensor, etc.).

Hereinafter, each embodiment of the heating type sensor mounted detection circuit will be described with reference to FIGS. 1 to 3. In each of the embodiments shown in FIGS. 1 to 3, the same components will be described with the same numbers.

[First embodiment]
As shown in FIG. 1, a heating type sensor mounted detection circuit 1A according to the first embodiment is schematically configured by arranging a heating type sensor 2A, a monitoring temperature sensor 4, and a control means 5 on a printed wiring board 3. .

The heating type sensor 2A includes a heater 2a mounted on the main body and a humidity sensor 2b that detects absolute humidity and relative humidity in the atmosphere, and the humidity information in the atmosphere detected by the humidity sensor 2b is transmitted to the control means 5. Output to.

The monitoring temperature sensor 4 is composed of a temperature sensor that detects the temperature of the printed wiring board 3 and outputs detected temperature information to the control means 5.

The control means 5 is composed of, for example, a microcomputer including a CPU, ROM, RAM, measurement circuit, etc., and includes a dew point temperature calculation section 5a and a heater control section 5b. The dew point temperature calculation unit 5a calculates the dew point temperature based on the humidity information from the humidity sensor 2b of the heating type sensor 2A and the temperature information from the monitoring temperature sensor 4. Furthermore, the heater control unit 5b controls the heater 2a of the heating type sensor 2A so that the temperature of the printed wiring board 3 detected by the monitoring temperature sensor 4 is higher than the dew point temperature calculated by the dew point temperature calculation unit 5a. do.

[Second embodiment]
As shown in FIG. 2, the heating type sensor mounted detection circuit 1B of the second embodiment includes a heating type sensor 2B, a monitoring temperature sensor 4, a monitoring humidity sensor 6, and a control means 5 arranged on a printed wiring board 3. It is roughly configured as follows.

The heating type sensor 2B includes a heater 2a mounted on the main body and a gas sensor 2c that detects the concentration of gas (for example, hydrogen, oxygen, carbon dioxide, etc.) in the atmosphere. The gas concentration information is output to the control means 5.

The monitoring temperature sensor 4 is composed of a temperature sensor that detects the temperature of the printed wiring board 3 and outputs detected temperature information to the control means 5.

The monitoring humidity sensor 6 is composed of a humidity sensor that detects the humidity (relative humidity) in the atmosphere, and outputs the detected humidity information to the control means 5.

The control means 5 is composed of, for example, a microcomputer including a CPU, ROM, RAM, measurement circuit, etc., and includes a dew point temperature calculation section 5a and a heater control section 5b. The dew point temperature calculation unit 5a calculates the dew point temperature based on the temperature information from the monitoring temperature sensor 4 and the humidity information from the monitoring humidity sensor 6. Furthermore, the heater control unit 5b controls the heater 2a of the heating type sensor 2B so that the temperature of the printed wiring board 3 detected by the monitoring temperature sensor 4 is higher than the dew point temperature calculated by the dew point temperature calculation unit 5a. do.

[Third embodiment]
As shown in FIG. 3, a heating type sensor mounted detection circuit 1C according to the third embodiment is schematically configured by arranging a heating type sensor 2C, a monitoring humidity sensor 6, and a control means 5 on a printed wiring board 3. .

The heating type sensor 2C includes a heater 2a mounted on the main body and a temperature sensor 2d that detects the temperature of the printed wiring board 3, and transmits information about the printed wiring board 3 detected by the temperature sensor 2d to the control means 5. Output.

The monitoring humidity sensor 6 is composed of a humidity sensor that detects the humidity (relative humidity) in the atmosphere, and outputs the detected humidity information to the control means 5.

The control means 5 is composed of, for example, a microcomputer including a CPU, ROM, RAM, measurement circuit, etc., and includes a dew point temperature calculation section 5a and a heater control section 5b. The dew point temperature calculating section 5a calculates the dew point temperature based on the temperature information from the temperature sensor 2d of the heating type sensor 2C and the humidity information from the monitoring humidity sensor 6. Further, the heater control unit 5b controls the heater of the heating type sensor 2C so that the temperature of the printed wiring board 3 detected by the temperature sensor 2d of the heating type sensor 2C is higher than the dew point temperature calculated by the dew point temperature calculation unit 5a. 2a.

On the printed wiring board 3 of the heating type sensor mounted detection circuits 1A, 1B, 1C of the first to third embodiments described above, a plurality of heat generating parts 7a (for example, a power supply, an IC such as a CPU, etc. ) are arranged.

Here, if the magnitude of waste heat of the heating type sensors 2A, 2B, 2C and each heat generating component 7a is approximately the same, as shown in FIGS. 4(a) to (c), the heating type sensors 2A, 2B, 2C, 2C and each heat generating component 7a are preferably arranged at equal intervals in the longitudinal direction of the printed wiring board 3. On the other hand, when the magnitude of waste heat of the heating type sensors 2A, 2B, 2C and each heat generating component 7a is different, as shown in FIGS. 5(a) to 5(c), In order to evenly conduct the waste heat of the heating type sensors 2A, 2B, 2C and each of the heat generating parts 7a, the printed wiring board 3 is adjusted according to the size of the waste heat of the heating type sensors 2A, 2B, 2C and each of the heat generating parts 7a. It is preferable to decide the intervals at which the heating type sensors 2A, 2B, 2C and each heat generating component 7a are arranged above. Thereby, the entire printed wiring board 3 can be heated evenly by the waste heat of the heating type sensors 2A, 2B, 2C and the heat generating component 7a. Furthermore, when heating the printed wiring board 3 using the waste heat of the heating type sensors 2A, 2B, 2C and the heat generating parts 7A, it is possible to heat the printed wiring board 3 more quickly by using the conductors (conductors such as wiring and grounding) on the printed wiring board 3. The waste heat from the heating type sensors 2A, 2B, 2C and the heat generating component 7A can be spread over the entire printed wiring board 3, which is more effective.

Note that the shaded areas in FIGS. 4(a) to 4(c) and FIGS. 5(a) to 5(c) are locations heated by the heated sensors 2A, 2B, 2C and the heat generating component 7a on the printed wiring board 3. In addition, the transition of waste heat conduction by the heating type sensors 2A, 2B, 2C and the heat generating component 7a is shown in FIG. 4(a) → FIG. 4(b) → FIG. 4(c), FIG. 5(a) → FIG. )→Schematically shown in FIG. 5(c).

In addition, the heated sensors 2A, 2B, and 2C are arranged at the center of the printed wiring board 3 in FIGS. 4(a) to (c), and at the ends of the printed wiring board 3 in FIGS. 5(a) to (c). However, the placement position is not limited, and the size of the waste heat of the heating type sensors 2A, 2B, 2C and each heat generating component 7a, and the circuit components 7 including the heat generating component 7a are taken into consideration on the printed wiring board. It is placed in the optimal position of 3.

Furthermore, when using the heating type sensor 2A (humidity sensor 2b) of the first embodiment or the heating type sensor 2B (gas sensor 2c) of the second embodiment, the heating type sensors 2A, 2B and the monitoring temperature sensor 4 are used. are arranged on the printed wiring board 3 in a state where they are thermally separated from each other. Specifically, as shown in FIG. 6, U-shaped notches 8 are formed in the printed wiring board 3 around the heating sensors 2A, 2B to connect the heating sensors 2A, 2B and the monitoring temperature sensor 4. are placed on the printed wiring board 3 in a thermally isolated state. Thereby, direct conduction of heat from the heating type sensors 2A and 2B to the monitoring temperature sensor 4 can be reduced.

[Concrete example]
In the heating type sensor 2A using the humidity sensor 2b, when a printed wiring board 3 with external dimensions of 20 mm x 90 mm x 1.6 mm is used, the heating type sensor 2A is heated to a maximum of about 500°C, and the printed wiring board 3 is heated. Although the temperature condition varies depending on the ambient temperature, the temperature around the sensor on the printed wiring board 3 can be maintained at approximately +5° C. to +15° C. above the ambient temperature.

In addition, in the heating type sensor 2B using the gas sensor 2c, when the printed wiring board 3 with external dimensions of 20 mm x 90 mm x 1.6 mm is used, the heating type sensor 2B is heated to a maximum of about 700°C, and the humidity sensor 2b is not used. Similar to the heated sensor 2A, the heating state of the printed wiring board 3 changes depending on the ambient temperature, but the temperature around the sensor on the printed wiring board 3 can be maintained at about +5°C to +15°C.

By the way, in each of the embodiments described above, the control means 5 stores in advance a dew point temperature conversion table for converting temperature and humidity (relative humidity) into dew point temperature, and each sensor (in the first embodiment, heating type sensor 2A (humidity sensor 2b) and monitoring temperature sensor 4; in the second embodiment, the monitoring temperature sensor 4 and monitoring humidity sensor 5; in the third embodiment, the heating type sensor 2C (temperature sensor 2d) The dew point temperature corresponding to the temperature information and humidity information (relative humidity) obtained from the monitoring humidity sensor 6) may be searched from a dew point temperature conversion table.

As described above, according to the present embodiment, the heating type sensors 2A, 2B, and 2C equipped with the heater 2a can be effectively used without requiring extra space for separately arranging a heating element as in the conventional case. This makes it possible to prevent dew condensation on the printed wiring board 3. Moreover, the heat source for heating the printed wiring board 3 is consumed not only by the heating type sensors 2A, 2B, and 2C equipped with the heater 2a, but also by the heat generating components 7a included in the circuit components 7 arranged on the printed wiring board 3. By using waste heat such as the amount of heat generated by heating, it is possible to heat the printed wiring board 3 and prevent dew condensation at a low cost without adding new heating parts or structural mechanisms, which also leads to energy savings. Furthermore, the effect remains unchanged even if the surrounding air is constantly close to saturated air.

Although the best mode of the heating type sensor mounted detection circuit according to the present invention has been described above, the present invention is not limited to the description and drawings based on this mode. That is, it goes without saying that all other forms, embodiments, operational techniques, etc. made by those skilled in the art based on this form are included in the scope of the present invention.

1A, 1B, 1C Detection circuit equipped with heating type sensor 2A, 2B, 2C Heating type sensor 2a Heater 2b Humidity sensor 2c Gas sensor 2d Temperature sensor 3 Printed wiring board 4 Monitoring temperature sensor 5 Control means 5a Dew point temperature calculation unit 5b Heater control unit 6 Humidity sensor for monitoring 7 Circuit parts 7a Heat generating parts 8 Notch

Claims (5)

a heating type sensor equipped with a heater and arranged on a printed wiring board and having a humidity sensor that detects humidity in the atmosphere;
a monitoring temperature sensor that detects the temperature of the printed wiring board;
A control means for calculating a dew point temperature based on the humidity detected by the humidity sensor and the temperature detected by the monitoring temperature sensor, and controlling the heater so that the temperature of the printed wiring board becomes higher than the dew point temperature. and
A detection circuit equipped with a heating type sensor, wherein the monitoring temperature sensor is arranged on the printed wiring board in a state that is thermally isolated from the heating type sensor. a heating type sensor equipped with a heater and arranged on a printed wiring board and having a gas sensor that detects the concentration of gas in the atmosphere;
a monitoring temperature sensor that detects the temperature of the printed wiring board;
a monitoring humidity sensor that detects humidity in the atmosphere;
A dew point temperature is calculated based on the temperature detected by the monitoring temperature sensor and the humidity detected by the monitoring humidity sensor, and the heater is controlled so that the temperature of the printed wiring board becomes higher than the dew point temperature. A detection circuit equipped with a heating type sensor, characterized in that it is equipped with a control means. a heating type sensor equipped with a heater and disposed on a printed wiring board and having a temperature sensor that detects the temperature of the printed wiring board ;
A monitoring humidity sensor that detects humidity in the atmosphere ,
A control means for calculating a dew point temperature based on the temperature detected by the temperature sensor and the humidity detected by the monitoring humidity sensor, and controlling the heater so that the temperature of the printed wiring board becomes higher than the dew point temperature. A detection circuit equipped with a heating type sensor. 3. The heating type sensor mounting detection circuit according to claim 2, wherein the monitoring temperature sensor is arranged on the printed wiring board in a state that is thermally isolated from the heating type sensor. Equipped with circuit parts including multiple heat generating parts,
The plurality of heat generating components are arranged on the printed wiring board according to the magnitude of the waste heat of the plurality of heat generating components so that the waste heat of the plurality of heat generating components is evenly conducted to the printed wiring board . The heating type sensor-equipped detection circuit according to any one of claims 1 to 4, characterized in that:

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