JP7046356B2 - Temperature sensor and its manufacturing method - Google Patents

Description

The present invention is attached to a temperature sensor, particularly a living body or an object, and when the temperature is detected by an electrode using the temperature dependence of the resistance value of the semiconductor layer or the polymer layer, the change with time of the temperature is accurately detected. The present invention relates to a temperature sensor suitable for attachment to a living body or an object because it can be monitored well and can be formed on a flexible base material.

As a temperature sensor, there is a plastic thermistor that uses a change in electrical characteristics depending on the temperature of a polymer thermosensitive body for temperature detection.

For example, Patent Document 1 discloses a temperature detecting device using a polyvinyl chloride composition in which an ion carrier is dispersed in a polymer thermosensitive body.

Further, Patent Document 2 discloses a highly flexible temperature sensor obtained by printing an acrylic monoma in which conductive particles are dispersed.

Further, as a semiconductor layer that can be formed by coating, a change in resistance value depending on the temperature of a PEDOT: PSS film is disclosed in Non-Patent Document 1.

Japanese Unexamined Patent Publication No. 57-133343 International Publication No. 2015/11205 Pamphlet

A. Benchirouf, et al. , Sensors and Actuators B 224 (2016) 344-350.

When the ion-conducting polyvinyl composition disclosed in Patent Document 1 is used for a temperature sensor, a thin and flexible film is formed by applying the ion-conducting polyvinyl composition on a thin and flexible plastic substrate. This is difficult, and therefore there is an inconvenient problem in attaching to a living body or an object.

Patent Document 2 discloses a resin composition for a temperature sensor, and describes that an acrylic monoma in which conductive particles are dispersed can be printed to form a thin film temperature sensor. However, the temperature of a human body is measured. It utilizes the change in resistance value in a specific narrow temperature range, and there is a problem in measurement in a wide temperature range. Further, when it is manufactured integrally with flexible electronics composed of an organic transistor made of an organic semiconductor, for example, a sensing circuit or a wireless communication circuit, there is a problem that it cannot be manufactured at the same time because it is different from a semiconductor material.

For example, when the semiconductor polymer disclosed in Non-Patent Document 1 is used for a temperature sensor, a thin and flexible film can be easily formed on a thin and flexible plastic substrate by a process of coating the semiconductor polymer. However, Fig. As suggested in 3 (a) that the change in resistance of the semiconductor polymer layer becomes unstable due to temperature, there is a difference in resistance between when the temperature rises and when the temperature drops, and accurate temperature changes can be monitored. Not.

An object of the present invention is to solve the above-mentioned problems, to form a thin and flexible temperature-sensitive body by coating on a thin and flexible substrate, to be excellent in attaching to a living body or an object, and to accurately change the temperature with time. Provided is a temperature sensor suitable for monitoring.

The present invention is a temperature sensor, in which a flexible base material containing plastic, a first electrode layer patterned on the base material, and a pattern formed on the base material apart from the first electrode layer. It is composed of a second electrode layer, a semiconductor polymer layer superimposed on the first electrode layer and the second electrode layer in a plan view, and an ionic polymer layer in which at least a part of the semiconductor polymer layer is covered. It is characterized in that a voltage is applied between the first electrode layer and the second electrode layer, the current between the first electrode layer and the second electrode layer is measured, and the resistance value is calculated.

In this temperature sensor, by providing an ionic polymer layer that covers at least a part of the semiconductor polymer layer, the difference in resistance value that occurs when the temperature rises and falls is suppressed, so that the temperature is accurate. Changes can be monitored.

By covering the semiconductor polymer layer with an ionic polymer layer, moisture absorption and dehumidification actions based on an appropriate affinity with water molecules in the ionic polymer layer work, and water is mixed into the semiconductor polymer layer. Suppresses the change in resistance value due to. As a result, it is presumed that the difference in resistance between the temperature rise and the temperature drop is significantly improved as compared with the case where only the semiconductor polymer layer is used.

The present invention is a temperature sensor, in which the semiconductor polymer layer is composed of a poly-3,4-ethylenedioxythiophene (PEDOT: PSS) film doped with poly-4-styrene sulfonic acid, and the ionic polymer layer is It is characterized by being composed of an imidazole-based ionic polymer.

In this temperature sensor, the semiconductor polymer layer is made of a PEDOT: PSS film, and the ionic polymer layer is made of an imidazole-based ionic polymer, so that a thin and flexible film can be formed in the coating process, which is preferable.

The present invention is a temperature sensor, characterized in that the first electrode layer and / or the second electrode layer is made of gold.

In this temperature sensor, since the electrode layer is made of gold, a thin and flexible film can be formed in the step of vacuum-depositing the gold-containing material, and it is also stable in redox, which is preferable.

The present invention is a temperature sensor, characterized in that the first electrode layer and / or the second electrode layer is made of silver.

In this temperature sensor, since the electrode layer is made of silver, a film can be formed in a low-temperature step of printing silver nanoparticle-dispersed ink, so that the selection of a base material can be expanded and mass productivity is excellent, which is preferable.

The temperature sensor of the present invention can be attached to a living body or an object to accurately monitor changes in temperature over time, and can be easily integrated with flexible electronics using organic semiconductors.

The cross-sectional view for demonstrating the structure of the temperature sensor which concerns on this invention. The figure which shows the time change of the resistance value with respect to the temperature change of the temperature sensor which concerns on this invention. As a modification, the figure which shows the time change of the resistance value with respect to the temperature change of the temperature sensor which concerns on this invention which the electrode layer is made of silver. As a comparative example, a cross-sectional view for explaining the configuration of a temperature sensor having only a semiconductor polymer layer. As a comparative example, it is a figure which shows the time change of the resistance value with respect to the temperature change of the temperature sensor of only a semiconductor polymer layer.

Hereinafter, embodiments of the present invention will be described. The temperature sensor according to the present invention has a flexible base material containing plastic, a first electrode layer patterned on the base material, and a first electrode layer patterned on the base material separated from the first electrode layer. It is composed of a two-electrode layer, a semiconductor polymer layer superimposed on the first electrode layer and the second electrode layer in a plan view, and an ionic polymer layer in which at least a part of the semiconductor polymer layer is covered. A voltage is applied between the one electrode layer and the second electrode layer, the current between the first electrode layer and the second electrode layer is measured, and the resistance value is calculated.

FIG. 1 illustrates a basic configuration of a temperature sensor according to the present invention. The first electrode layer 2 and the second electrode layer 3 are formed on the surface of the base material 1, and the semiconductor polymer layer 4 is superposed on the first electrode layer 2 and the second electrode layer 3, and finally the semiconductor polymer layer 4. The temperature sensor is configured by forming the ionic polymer layer 5 that covers the above.

A voltage is applied to the first electrode layer 2 and the second electrode layer 3 via a power source (not shown), and a resistance value is calculated from the detected current value to correspond to the temperature.

As the material of the base material 1, for example, polyethylene naphthalate, polyethylene terephthalate, polyethylene, polyimide, a resin such as polyparaxylylene (Parylene (registered trademark)), paper, or the like can be used.

As the material of the first electrode layer 2 and the second electrode layer 3, for example, gold, silver, copper, platinum, aluminum, carbon, indium tin oxide (ITO) and the like can be used.

As the material of the semiconductor polymer layer 4, for example, poly-3,4-ethylenedioxythiophene (PEDOT: PSS), polyaniline, polypyrrole or the like doped with poly-4-styrenesulfonic acid can be used.

As the material of the ionic polymer layer 5, imidazole-based ionic polymer, ammonium-based ionic polymer, piperidinium-based ionic polymer, pyrrolidinium-based ionic polymer, pyridinium-based ionic polymer, phosphonium-based ionic polymer, and sulfonium-based ion. Sex polymers, 1,4-diaza-2,2,2-bicyclooctanium-based ionic polymers and the like can be used.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the following examples.

FIG. 1 is a cross-sectional view for explaining the configuration of the temperature sensor according to the present invention. Gold (thickness 50 nm) is vapor-deposited on the polyethylene naphthalate (PEN) film (thickness 120 μm) of the base material 1 through a through-hole mask using a vacuum vapor deposition apparatus to form the first electrode layer 2 and the second electrode layer 2. A pattern with the electrode layer 3 was prepared. The shape of the electrode pattern is not limited to this, but the electrode widths of the first electrode layer 2 and the second electrode layer 3 are 1 to 3 mm, respectively, and the distance between the first electrode layer 2 and the second electrode layer 3 is 2 mm. And said.

Poly-3,4-ethylenedioxythiophene (PEDOT) doped with poly-4-styrene sulfonic acid using a dispenser device (manufactured by Musashi Engineering Co., Ltd.) superimposed on the first electrode layer 2 and the second electrode layer 3. : PSS) was applied and fired at 120 ° C. for 60 minutes to form a semiconductor polymer layer 4 having a thickness of 5 μm. Finally, using a dispenser device (manufactured by Musashi Engineering Co., Ltd.) so as to cover the semiconductor polymer layer 4, an imidazole-based ionic polymer is applied and fired at 120 ° C. for 60 minutes to obtain an ionic polymer layer 5 having a thickness of 5 μm. Formed.

In this temperature sensor, since the semiconductor polymer layer 4 is PEDOT: PSS and the ionic polymer layer 5 is an imidazole-based ionic polymer, laminated film formation by coating or printing can be easily performed, which is preferable.

Since the first electrode layer 2 and the second electrode layer 3 are formed by vapor deposition of gold, they are extremely stable against chemical corrosion due to heat, moisture, oxygen and acid, alkali, etc., and heat conduction and electricity. It is preferable because an electrode having excellent conduction can be formed.

FIG. 4 is a cross-sectional view for explaining the configuration of a temperature sensor as a comparative example. The only difference from the example of the temperature sensor shown in FIG. 1 is that the ionic polymer layer 5 is not provided.

Next, the detection method using the temperature sensor of the present invention will be described in detail. The voltage control between the first electrode layer 2 and the second electrode layer 3 and the current measurement between the first electrode layer 2 and the second electrode layer 3 are performed by using a 2400 Source Meter device (manufactured by KEITHLEY). went. The applied voltage was a DC voltage. By using a DC voltage, the circuit configuration can be further simplified, the element can be miniaturized, and the wearable can be made, which is preferable.

FIG. 2 is a diagram showing the time change of the resistance value with respect to the temperature change of the temperature sensor of the embodiment, and FIG. 5 is a diagram showing the time change of the resistance value with respect to the temperature change of the temperature sensor of the comparative example.

2 and 5 will be described in detail. A temperature sensor consisting of an example and a comparative example was installed in a cool plate device (scp125, manufactured by AsONE), and the temperature was raised from 25 ° C to 80 ° C at 5 ° C intervals, and then from 80 ° C to 25 ° C at 5 ° C intervals. The temperature dropped at. A DC voltage of 0.1 V was applied between the first electrode layer 2 and the second electrode layer 3, and the current between the first electrode layer 2 and the second electrode layer 3 was measured to calculate the resistance value. ..

The resistance value of the temperature sensor of the comparative example shown in FIG. 5 indicates that a difference of 380 Ω occurs between the temperature rise and the temperature decrease, whereas the resistance value of the temperature sensor of the embodiment shown in FIG. 2 raises the temperature. It is shown that the difference between the time and the temperature decrease is reduced to 0.258Ω. This indicates that the temperature sensor of the embodiment can suppress the difference in resistance between the temperature rise and the temperature decrease of the semiconductor polymer layer 4 due to the provision of the ionic polymer layer 5. .. From the above, the temperature sensor of the embodiment can prevent the change in resistance due to temperature from becoming unstable and can accurately monitor the change in temperature.

As a modification, the first electrode layer 2 and the second electrode layer 3 are formed by printing silver nanoparticle dispersion ink, and polyethylene terephthalate having lower heat resistance than polyethylene naphthalate (PEN) is used for the base material 1. It is the same as the above-mentioned embodiment except that (PET) is used.

Using a dispenser device (manufactured by Musashi Engineering Co., Ltd.), silver nanoparticle dispersion ink is applied to the base material 1 on a polyethylene terephthalate (PET) film (thickness 120 μm) and fired at 120 ° C. for 30 minutes to a thickness of 50 nm. The patterns of the first electrode layer 2 and the second electrode layer 3 of the above were prepared. The pattern shape was the same as in the above embodiment.

FIG. 3 is a diagram showing the time change of the resistance value with respect to the temperature change of the temperature sensor of the modified example. A temperature sensor made of a modified example was installed in a cool plate device (scp125, manufactured by AsONE), the temperature was raised from 25 ° C. to 80 ° C. at intervals of 5 ° C., and then the temperature was lowered from 80 ° C. to 25 ° C. at intervals of 5 ° C. A DC voltage of 0.1 V was applied between the first electrode layer 2 and the second electrode layer 3, and the current between the first electrode layer 2 and the second electrode layer 3 was measured to calculate the resistance value. .. The voltage control between the first electrode layer 2 and the second electrode layer 3 and the current measurement between the first electrode layer 2 and the second electrode layer 3 are performed by using a 2400 Source Meter device (manufactured by KEITHLEY). went.

It is shown that the resistance value of the temperature sensor of the modified example shown in FIG. 3 has a difference of 0.265 Ω when the temperature is raised and when the temperature is lowered. It can be seen that this difference in resistance value is significantly reduced as compared with the comparative example of FIG. 5, as in the case of the embodiment of FIG. It can be seen that even in the temperature sensor of the modified example, it is possible to suppress the difference in the resistance value of the semiconductor polymer layer 4 between the temperature rise and the temperature decrease due to the provision of the ionic polymer layer 5. .. From the above, the temperature sensor of the modified example can prevent the change in resistance due to temperature from becoming unstable and can accurately monitor the temperature change.

Further, by forming the first electrode layer 2 and the second electrode layer 3 by printing silver nanoparticles dispersed ink, the processing temperature in the process can be lowered, so that the restriction on the heat resistance of the base material 1 is relaxed, and polyethylene terephthalate is used. (PET) film and the like can be used and can be provided at low cost, which is preferable.

Since the temperature sensor described above can be formed on the flexible base material 1, it can be attached to a living body or an object to accurately monitor changes in temperature over time. Further, these effects are great, such as being an effective means for integrating with a sensing circuit or a wireless communication circuit using an organic semiconductor on the base material 1 of the sensor.

1 Base material 2 First electrode layer 3 Second electrode layer 4 Semiconductor polymer layer 5 Ionic polymer layer

Claims (9)

With a flexible substrate containing plastic,
The first electrode layer patterned on the substrate and
A second electrode layer formed on the base material in a pattern separated from the first electrode layer,
A semiconductor polymer layer superimposed on the first electrode layer and the second electrode layer in a plan view,
An ionic polymer layer that covers at least a part of the semiconductor polymer layer,
A temperature sensor consisting of. The semiconductor polymer layer is composed of a poly-3,4-ethylenedioxythiophene (PEDOT: PSS) film doped with poly-4-styrene sulfonic acid.
The ionic polymer layer is made of an imidazole-based ionic polymer.
The temperature sensor according to claim 1. The first electrode layer and / or the second electrode layer is made of gold.
The temperature sensor according to claim 1 or 2. The first electrode layer and / or the second electrode layer is made of silver.
The temperature sensor according to claim 1 or 2. A DC voltage is applied between the first electrode layer and the second electrode layer,
The resistance value is calculated by measuring the current between the first electrode layer and the second electrode layer.
The temperature sensor according to any one of claims 1 to 4. A first electrode layer patterned on a flexible substrate containing plastic,
A step of forming a second electrode layer having a pattern formed apart from the first electrode layer, and a process of forming the second electrode layer.
A step of forming a semiconductor polymer layer superimposed on the first electrode layer and the second electrode layer in a plan view, and
The step of forming an ionic polymer layer in which at least a part of the semiconductor polymer layer is covered, and
Manufacturing method of temperature sensor including. The step of forming the semiconductor polymer layer includes a step of applying poly-3,4-ethylenedioxythiophene (PEDOT: PSS) doped with poly-4-styrene sulfonic acid.
The step of forming the ionic polymer layer includes a step of applying an imidazole-based ionic polymer.
The method for manufacturing a temperature sensor according to claim 6. The step of forming the first electrode layer and / or the second electrode layer includes a step of vacuum-depositing the gold-containing material.
The method for manufacturing a temperature sensor according to claim 6 or 7. The step of forming the first electrode layer and / or the second electrode layer includes a step of printing a silver nanoparticle dispersion ink.
The method for manufacturing a temperature sensor according to claim 6 or 7.

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