JPH02281704A - Thin film platinum temperature sensor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a thin film platinum temperature sensor used in automobiles, household appliances, industrial instruments, and the like.

BACKGROUND OF THE INVENTION Conventional temperature sensors can be broadly divided into those that have high accuracy but are expensive and cumbersome to handle, and those that are simple and can be used in large quantities but have poor accuracy, and are used depending on the purpose.

However, recent rapid advances in electronics have created a need for temperature sensors that are robust, can be used in large quantities, and have high accuracy.

In particular, precision temperature sensors for automobiles are required to be inexpensive, compact, highly accurate, have a wide temperature range, have linear resistance changes, be resistant to vibration, and have good thermal response. ing. Traditionally.

A platinum resistance thermometer pair is used as a precision temperature sensor, but since platinum wire is used, the resistance value is 60Ω, 10Ω.
This has the problem of complicating peripheral circuits and being susceptible to noise from peripheral circuits. The shape is also large.

Furthermore, it is susceptible to vibration and shock, and there is a limit to how thin the platinum wire can be made, so mass production is impossible because expensive platinum wire is wound one by one around a ceramic bobbin, etc., and it is quite expensive. It had become a thing.

In order to solve these problems, temperature sensors using thick or thin platinum films instead of platinum wires have been developed. However, thick film platinum temperature sensors.

Fine print of less than 100 μm due to screen printing technology
It has drawbacks such as difficulty in patterning and large manufacturing variations.

On the other hand, thin-film platinum temperature sensors can be miniaturized because the pattern can be made finer, and have higher sensitivity due to higher resistance.Also, they have strong mechanical strength and can reduce variations through Uni-No treatment, making them suitable for mass production. It has advantages such as low cost.

Problems to be Solved by the Invention Methods for manufacturing thin film platinum temperature sensors include vacuum evaporation,
A platinum thin film resistor having a thickness of several thousand angstroms is formed on an insulating substrate by sputtering, CVD, or the like, and then finely patterned by wet etching, sputter etching, or the like. Furthermore, 900~1ooo℃ in the atmosphere
Heat treatment is performed at high temperatures. After that, the resistance value is adjusted by trimming, the lead wire is taken out, and a protective film is coated.

At this time, an alumina substrate or the like is used as the insulating substrate. However, with the current method of forming a platinum thin film resistor on only one side of an alumina substrate, the surface area of the substrate is limited, so there is a limit to improving the heat dissipation effect of the platinum film, which is the temperature sensing part, and the thermal response It was difficult to improve sexual performance. Furthermore, since the specific resistance of platinum is fixed, the only way to increase sensitivity by increasing resistance is to make the platinum pattern finer, the platinum film thinner, or the substrate larger.

As a result, mechanical strength and resistance-temperature characteristics deteriorate significantly, and when ultra-fine patterns are formed, there is a risk of pattern breakage. Furthermore, when measuring the temperature of a fluid, there is a risk that the response speed may vary depending on the combination of the direction in which the fluid flows and the direction of the pattern, making it difficult to measure fluids that flow in multiple directions.

As described above, the conventional method of depositing a platinum thin film has many problems.

In view of these problems, the present invention has a fast thermal response speed,
The object of the present invention is to provide a thin film platinum temperature sensor that has good measurement accuracy and is compact in size.

Means for Solving the Problems In order to achieve the above object, the present invention has a platinum thin film resistor and an electrode on both sides of an insulating substrate, each platinum thin film resistor is electrically connected through a through hole, and the platinum The thin film resistor patterns are characterized in that they are arranged in different directions.

Function The present invention forms the platinum thin film resistor of the temperature sensitive part on both sides of the above-mentioned substrate, and increases the area of the platinum thin film resistor of the temperature sensitive part without making the board large or the pattern fine. In addition to improving the accuracy and thermal response speed of the sensor itself. Furthermore, by changing the direction of the platinum thin film resistor patterns on both sides, it is possible to reduce variations in thermal response speed with respect to the direction of the fluid.

Embodiment Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

In FIG. 1, 1 is an alumina substrate having a width of 3 mm, a length of 10+++ m, and a thickness of 0.5 m. 2! L, 2b is C
The platinum thin film resistor is formed by depositing platinum to a thickness of approximately 0.6 μm using the VD method and patterning it using the sputter etching method, and is formed on both sides of the alumina substrate 1. The platinum thin film resistor 2b on the other side has a pattern parallel to the longitudinal direction of the alumina substrate 1. Reference numeral 3 denotes an electrode for leading out a lead wire connected to this platinum thin film resistor 2, 4 a through hole provided on both sides of the substrate for making the platinum thin film resistor 2 conductive, and 5 a SiO□ covering the platinum thin film resistor 2. It is a protective film consisting of. Further, 6 is a lead wire connected to the electrode 3.

As the thermal time constant of the temperature sensor in this example.

When the temperature sensor was moved from 20°C to 100°C, we measured the time it took to reach a resistance value equivalent to 63.2% of the temperature difference between 20°C and 100°C. The thermal response was approximately 1/4 of that of the one with . Furthermore, the maximum variation in thermal response speed due to the directionality of the fluid was about 1/2 compared to the case where patterns were arranged in the same direction on the front and back sides.

Effects of the Invention As described above, according to the present invention, by forming platinum thin film resistors on both sides of a substrate and arranging the platinum thin film resistor patterns in different directions on the front and back sides, a thin film platinum temperature sensor can be used. , it is possible to realize a temperature sensor with fast thermal response, improved heat dissipation effect, excellent measurement accuracy, and less measurement variation depending on the direction of fluid without increasing the size of the alumina substrate.

[Brief explanation of drawings]

Figures 1a, b, and c are a front view, a back view, and a sectional view of a thin film platinum temperature sensor according to an embodiment of the present invention. 1...Alumina substrate, 2N, 2b...
Platinum thin film resistor, 3... Electrode, 4...
Through hole, 6...Protective film, 6...
Lead. Name of agent: Patent attorney Shigetaka Awano and one other name
l Diagram/-Furumitsu nose rings, Zb-Usukikichokorojin body 3-Electrode 4--S) Lehhornre 5-Hosetsuri Sootsu--Seed 碌

Claims (1)

[Claims] A platinum thin film resistor and an electrode are provided on both sides of an insulating substrate, each platinum thin film resistor is electrically connected through a through hole, and the patterns of the platinum thin film resistor are arranged in different directions. thin film platinum temperature sensor.