JPH04344434A - Temperature sensor - Google Patents

Abstract

PURPOSE:To acquire a sensor which shows favourable sensitivity in a temperature territory from normal temperature to moderate temperature and is good in heat resistance by using a conductive film consisting of an organic high polymer/metal complex as a temperature sensing element and by detecting change of resistance value of this film by temperature. CONSTITUTION:A conductive film consisting of an organic high polymer/metal complex is used as a temperature sensing element, and change of resistance value of this film by temperature is detected through a double-pole terminal set on the film and temperature is detected. The conductive film is an organic high polymer/metal complex made of a mixture of a conjugate high polymer formed by plasma polymerization and a metal formed by spattering. The conjugate high polymer is formed by plasma polymerization of a conjugate organic monomer as a starting material. The conjugate organic monomer is the one with conjugate double bond, for example, naphthalene, perylene or others. Plasma polymerization of the conjugate organic monomer is carried out by supplying power between the terminals in a container regulated to be specified pressure by carrier gas.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature sensor.

0002

[Prior Art] Conventionally, temperature sensors used in the temperature range from room temperature to medium temperature (approximately 200°C) include:
Oxide systems such as Mn, Co, Ni, Fe, Cu, V, Ba
It is known that a thermistor made of oxides such as , Sr, etc. is used as a temperature sensing element.

However, the above-mentioned temperature sensor has the disadvantage that it requires high-temperature baking treatment when the temperature-sensitive element is provided on the substrate, and the substrate material is limited to materials that can withstand high temperatures, such as ceramic substrates such as alumina. was there. Furthermore, since it is not easy to increase the area of the temperature sensing element, it is not suitable for detecting the temperature of a planar body.

[0004] In order to solve the above-mentioned drawbacks, temperature sensors using organic polymer materials have been proposed.
JP-A-2-156502 discloses a temperature sensing element made of carbon black and a polymer binder, but since the polymer binder has a low heat resistance temperature, this temperature sensor can only be used at medium temperatures ( In the region (about 200° C.), the sensitivity of temperature detection is poor, and furthermore, because the film thickness of the temperature sensing element is non-uniform, the absolute sensitivity of temperature detection is poor. In addition, the manufacturing process is complicated, so it is not practical.

[0005]

[Problems to be Solved by the Invention] The present invention has been made to solve the above-mentioned drawbacks, and its purpose is to exhibit good sensitivity in the temperature range from room temperature to medium temperature (approximately 200°C), and to have heat resistance. The object of the present invention is to provide a temperature sensor that has excellent properties and is suitable for detecting the temperature of a planar object.

[0006]

[Means for Solving the Problems] The temperature sensor of the present invention uses a conductive film made of an organic polymer/metal composite as a temperature sensing element, and detects changes in the resistance value of this film due to temperature by installing a device on the film. It is designed to detect temperature through two polar electrodes.

The conductive film is an organic polymer/metal composite made of a mixture of a conjugated polymer formed by plasma polymerization and a metal formed by sputtering, and the plasma polymerization and sputtering are performed in the same container. is carried out at the same time.

[0008] The above conjugated polymer is a conjugated organic monomer.
The conjugated organic monomer is not particularly limited as long as it has a conjugated double bond, such as naphthalene, pyrene, perylene, and derivatives thereof ( For example, fused aromatic compounds such as naphthalenetetracarboxylic dianhydride, naphthalenetetracarboxylic diimide and derivatives thereof, perylenetetracarboxylic dianhydride, perylenetetracarboxylic diimide and derivatives thereof,
and phenyl compounds represented by the following general formula.

[0009]

[Chemical formula 1]

(In the formula, R1 and R2 represent hydrogen, halogen, hydroxyl group, alkyl group, alkoxy group, sulfone group, nitrile group, vinyl group, etc., and n is an integer of 1 or more.) Examples of the above phenyl compound include: biphenyl, 4,4
Biphenyl compounds such as '-biphenyldiol, terphenyl compounds such as p-terphenyl, p-quarter-phenyl, 4-hydroxy-p-quarter-phenyl, 4
, 4'-dihydroxy-p-quarter-phenyl, and derivatives thereof.

[0011] The plasma polymerization of the conjugated organic monomer is carried out in a container whose pressure is adjusted to a constant level with a carrier gas by supplying electric power between electrodes. For example, when the monomer is a liquid, the monomer can be supplied by vaporizing it outside the container and then introducing the vapor into the container. In this case, the monomer may be evaporated or sublimated by resistance heating in a container. The temperature at which the monomer is evaporated or sublimed by resistance heating is determined as appropriate depending on the type of monomer, and is, for example, 50 to 400 m
°C is preferred.

[0012] As the carrier gas, for example, N2
, Ar, and the like are preferably used, and the pressure at that time is preferably 10-1 to 10-4 Torr, more preferably 10-2 to 10-3 Torr.

[0013] The type of power to be supplied is not particularly limited, and for example, the frequency is 10kHz to
35 kHz or 10 MHz to 50 MHz, direct current, etc. can be suitably used, and the output thereof is preferably 50 W to 1 kW, more preferably 50 to 300 W.

The metal to be sputtered is not particularly limited, and includes, for example, gold, silver, copper, iron,
Single metals such as tin, chromium, nickel, cobalt, and titanium, and their alloys (stainless steel, nickel alloy cast iron,
bronze, etc.).

[0015] The above metal sputtering is carried out by using a metal as an anode electrode material, and supplying electric power between the electrodes to ionize and accelerate the carrier gas in a container adjusted to a constant pressure with a carrier gas. This is done by sputtering the metal electrode.

Since the above sputtering is carried out simultaneously with the plasma polymerization of the organic monomer in the same container, the conditions are the same as the above plasma polymerization conditions. The thickness of the conductive film formed by the above method is not particularly limited, but as it becomes thinner, pinholes are more likely to occur, and as it becomes thicker, the sensitivity of temperature detection decreases due to the increase in electrical resistance of the film. 100 Å to 5 μm is preferable because
More preferably, it is 200 Å to 1 μm.

The conductive film used as the temperature-sensitive element in the present invention may be formed directly on the substrate depending on the installation form of the two electrodes to be installed, or may be formed directly on the substrate after one electrode is formed on the substrate. It may be formed on the electrode.

[0018] The above-mentioned substrates include, for example, glass, ceramics, metals, and plate-like or film-like materials such as polymers such as acrylic, vinyl, polyolefin, polyester, polyamide, and polycarbonate. Examples include bodies, and the shape thereof may be planar or curved.

The material used for the two electrodes is not particularly limited as long as the resistance value has little temperature dependence; for example, gold, silver, stainless steel, etc.
Examples include metals such as metal, and inorganic semiconductors such as indium tin oxide (hereinafter referred to as ITO).

Examples of methods for forming the two electrodes include methods such as vacuum evaporation, sputtering, etc., and methods in which a paste-like material is applied and dried.

Examples of the form in which the two electrodes are installed on the temperature sensing element made of the conductive film include, for example, a comb-shaped electrode type in which the two electrodes are arranged in a comb shape on either side of the conductive film; Examples include sandwich electrode types in which electrodes are placed on both sides of a conductive film, and when the resistance value of the conductive film is low,
It is preferable to use a comb-shaped electrode type, and when the resistance value of the conductive film is high, it is preferable to use a sandwich electrode type.

[0022]

[Examples] The present invention will be explained below with reference to Examples.

Example 1 A glass substrate on which ITO was vapor-deposited was placed on the lower electrode (cathode) in a reaction vessel in which a parallel plate electrode (anode) made of stainless steel plate (SUS-304) was installed, and a glass substrate was placed separately in the reaction vessel. 4,4'-dihydroxy-p-quarter phenyl was supplied to the tungsten board, and the inside of the container was
After reducing the pressure to 0-5 Torr, Ar gas was supplied so that the total pressure inside the container was 1 x 10-2 Torr.

Next, a current was passed through the tungsten board to heat the 4,4'-dihydroxy-p-quarter phenyl to 300°C, and a low frequency of 13kHz was applied between the electrodes at an output of 100W. , 500 Å on the ITO film
A conductive film with a thickness of .

Elemental analysis of the formed conductive film was performed by X-ray photoelectron spectroscopy, and the ratio of the number of atoms of the main element was found to be C.
:48%, O:35%, Fe:8%, and Cr:3%. Gold was vacuum-deposited on the unit cell under a reduced pressure of 1 x 10-5 Torr to form a counter electrode with a size of 6 mm2 and a thickness of 700 Å, thereby obtaining a temperature sensor.

[0026] Conductive wires were connected to the ITO electrode and gold electrode of the obtained temperature sensor, and the temperature dependence of the resistance value at each temperature (20°C to 120°C) was evaluated. The results are shown in Table 1 and Figure 1.
It was shown to.

[0027]

[Table 1]

Further, after heating the above sensor to 200°C, the temperature dependence of the resistance value was evaluated again at 20°C to 120°C, and there was no change in performance.

[0029]

Effects of the Invention The structure of the temperature sensor of the present invention is as described above, and as a temperature sensing element, an organic polymer-metal which is formed by simultaneously performing plasma polymerization of a conjugated organic monomer and sputtering of a metal is used. Because it uses a conductive film made of a composite material, it exhibits good sensitivity in the temperature range from room temperature to medium temperature (approximately 200 degrees Celsius), and has excellent heat resistance, making it a temperature sensor suitable for detecting the temperature of planar objects. .

[Brief explanation of the drawing]

FIG. 1 is a graph showing the change in resistance value at each temperature of the temperature sensor of the present invention.

Claims (1)

[Claims] 1. A temperature sensor comprising two electrodes installed on a temperature sensing element, wherein the temperature sensing element is formed by simultaneously performing plasma polymerization of a conjugated organic monomer and sputtering of a metal. A temperature sensor characterized in that it is a conductive film made of an organic polymer-metal composite.