JPS61148732A - Thermosensitive element - 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 temperature sensing element. More specifically, the present invention relates to a temperature sensing element that is effectively used in fuse resistor applications and the like.

[Conventional technology]

A fuse resistor normally functions as a resistor, but if an excessive current flows due to a circuit failure or some other cause, it will melt and fray the fuse.

Thus, the fuse resistor not only serves two purposes with one component, but also provides a certain degree of reliable protection by having more precise fusing characteristics than ordinary fuses.

Fuse resistors that play this role are usually carbon film resistors or metal film resistors with a part of the film made extremely thin, and when an excessive current flows through that part, it overheats and burns out. However, such a structure has the following drawbacks.

(1) If there are defective pinholes or the like in the portion of the resistive film that is to be fused, or if the adhesion to the substrate is insufficient, the current value at which the film burns out will vary.

(2) Since a part of the resistive film is made thin, it is difficult to obtain a low resistance value.

(+1) It is dangerous because the temperature at which it burns out is close to 1500°C.

[Problem that the invention seeks to solve]

In view of the current need for this type of application to provide more reliable and safe protection without exhibiting these drawbacks of conventional fuse resistors, the present inventors As a result of various studies in search of a solution to these problems, they found that a temperature-sensitive element having the following structure satisfactorily meets these objectives.

[Means for Solving the Problems] and [Operation] Accordingly, the present invention relates to a temperature sensing element, which comprises a thin film resistor made of an amorphous metal compound formed on an insulating substrate. .

As the insulating substrate, for example, a glass plate, a quartz plate, an alumina plate, etc. having a thickness of approximately 1 to 3 m is used. In addition, the amorphous metal compounds formed as thin film resistors on these substrates include 'l''INNT&NZrN, Nb, whose crystal structure is easily changed by annealing.
Metal nitrides such as N and VN are preferably used. Formation of an amorphous thin film resistor is generally performed by high frequency Macnetron sputtering using these metal nitrides as a target. This method can form a thin film with a thickness of about 0.01 to 10 μm at a low temperature, and by forming the film into a thin film, the response speed of the temperature-sensitive element is improved.

The shape of the thin film resistor can be made into any shape by masking when applying the high frequency Macnetron sputtering method, but generally it is zigzag, straight, or
It is used in a planar shape, and by selecting the shape and width, the outer shape can be made small, and thus an arbitrary resistance value can be obtained.

FIG. 1 is a plan view of one embodiment of the temperature-sensitive element according to the present invention, and will be explained with reference to an example of the dimensions described for reference.
7 x 2 m), a linear thin film-like amorphous metal nitride resistor 2 with a width of 1 woa and a thickness of 0.3 μm is placed on the
The wires are formed in a zigzag shape with equal intervals, and both ends thereof are connected to lead wires 4 and 4' with silver paste 3.3' attached thereto.

When an excessive current flows through a temperature sensing element with such a structure, gold i
The temperature of the A nitride resistor increases, and the element temperature increases to 150℃.
When the temperature exceeds ℃, the resistance value of the resistor starts to increase. The degree of increase in resistance varies depending on the temperature, and the higher the temperature, the faster the rate of increase, and eventually a certain resistance value is reached. With the dimensions of the embodiment shown in Figure 1, the element resistance value over time when the resistor is a titanium nitride thin film is shown in the graph of Figure 2, and the element resistance is better and equilibrated more quickly at high temperatures. It turns out that the state trap is reached. '・The principle behind the resistance change in response to such temperature changes is that the thin film resistor is formed at low temperatures by high-frequency magnetron sputtering, so it is in an amorphous state, and when it is heated to 150°C or higher, it shows a tendency to crystallize. This is due to the annealing effect, which causes the resistance to change.

For example, in the case of a titanium nitride thin film resistor,
When heated above 150℃, (111), (200
), especially since it has a (200) plane orientation.

In this way, resistance increases due to the generated temperature, and this makes it possible to limit the circuit current, thereby suppressing further temperature rise. If the temperature rise cannot be suppressed by increasing the resistance, or if the overcurrent is extremely large and the temperature rises rapidly, set the resistance between the initial resistance and the equilibrium resistance in preparation for such a situation. The safety of the circuit coefficients can be ensured by installing a resistor and turning off the power via a relay when the resistance value is reached, or using a lamp or buzzer to notify that the set value has been reached. can be achieved.

〔Effect of the invention〕

The temperature sensing element according to the present invention has the following characteristics.

(1) Since the resistance value changes due to changes in the crystal structure of the resistor thin film, it can be used in applications such as fuse resistors, and in this case it is safer than conventional types that burn out at high temperatures.

(2) By keeping the width of the thin film resistor constant and varying its thickness, the resistance value can be changed arbitrarily.

(3) Since the shape and size of the thin film resistor can be arbitrarily set, it can be made into very small particles, and it can also be directly formed on objects with complex shapes.

[Brief explanation of the drawing]

FIG. 1 is a plan view of one embodiment of a temperature-sensitive element according to the present invention. Furthermore, FIG. 2 is a graph showing changes over time in element resistance at various temperatures of a temperature-sensitive element using an amorphous titanium nitride thin film resistor. (Explanation of symbols) 1...Insulator substrate

Claims (1)

[Scope of Claims] 1. A temperature-sensitive element comprising a thin film resistor made of an amorphous metal compound formed on an insulating substrate. 2. The temperature-sensitive element according to claim 1, wherein the amorphous metal compound is a metal nitride. 3. Claim 1 or 2, in which the thin film resistor is formed by high frequency magnetron sputtering.
Temperature sensing element described in section. 4. The temperature sensing element according to claim 1, which is used as a fuse resistor.