JPS6115562B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermistor having a structure that can be selected to have any resistance value at any temperature.

One method of measuring the temperature of an object or atmosphere is to use a thermistor. By the way, temperature measurement using a thermistor element alone does not provide sufficient accuracy, so in the bridge-type temperature measurement method, which uses a single constant temperature point as shown in Figure 1, which is an improved measurement method, the resistance Due to the need to balance the values, an extra variable resistor was required. That is, as shown in FIG. 1, a bridge circuit is configured by resistors 1 and 2, thermistors 3 and 4, and variable resistor 5, and output 7 is obtained from two signals inputted to operational amplifier 6 from points A and B. The temperature difference between the thermistors 3 and 4 is determined by taking out the temperature, and at this time, in order to balance the bridge,
A variable resistor 5 was required. The present invention makes it possible to configure a temperature or humidity measurement system using such a bridge-type thermistor temperature sensor or humidity measurement system without requiring an externally attached variable resistor. Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a temperature measurement system using a thermistor, which is a first embodiment of the present invention.

As shown in the figure, resistors 11 and 12 and thermistors 13 and 14 form a bridge circuit, which is input to an operational amplifier 15 from points C and D to obtain an output 16. Here, the thermistor 14 is according to the present invention, and by changing only the resistance value without changing the temperature characteristics of the thermistor, and making the resistance value match the temperature measurement circuit, the circuit is simplified, stability is improved, This improves reliability. The structure of such a variable resistance type thermistor is specifically shown in FIG. As shown in the figure, a temperature-sensitive film 22 made of silicon carbide, manganese, cobalt, iron-based oxide, etc. is deposited on the surface of a substrate 21 made of alumina or the like by sputtering vapor deposition.
It is provided in a semicircular shape by a method such as vapor deposition or screen printing. Metal electrode parts 23 and 24 are provided at both ends of this coating 22, and lead wires 25 and 26 are provided in the electrode parts 23 and 24, respectively. Next, a contactor 27 that moves while contacting the coating 22 is attached by a stator 28 . The stator 28 is fixed so that the contact 27 can rotate. Note that the coating 22
As shown in the figure, if it is narrower in the portions close to the electrode parts 23 and 24 and widened in the center, it becomes easier to finely adjust the resistance value in the center portion, making it easier to obtain the desired resistance value. . In addition, the narrow part has a small thermal time constant, so the differential coefficient of resistance change with respect to minute temperature changes is large.
A thermistor with high thermal sensitivity.

FIG. 4 shows a thermistor according to a second embodiment of the present invention, in which a temperature-sensitive film 32 made of silicon carbide, manganese-cobalt-iron oxide, etc. is deposited on the surface of a substrate 31 made of alumina or the like by sputtering vapor deposition. It is provided in a band shape as shown in the figure using a method such as vapor deposition or screen printing. Metal electrode portions 3 are provided at both ends of this coating 32.
3 and 34 are provided, and lead wires 35 and 36 are provided to the electrode portions 33 and 34, respectively. Next, a contactor 37 that can move while contacting the coating 32 is attached by fitting or the like. In addition, contact 37
can move while simultaneously touching the elongated electrode portion 38 connected to the electrode 34.
Further, the coating 32 has electrode parts 33 and 34 as shown in the figure.
If the width is narrow in the vicinity of , and widened in the center, fine adjustment of the resistance value in the center becomes easier as in the first embodiment, making it easier to obtain the desired resistance value. Furthermore, since the narrow portion has a small thermal time constant, the differential coefficient of resistance change with respect to minute temperature changes is large, resulting in a thermistor with high thermal sensitivity.

In addition, in FIGS. 3 and 4, the contacts 27, 3
7 are electrically connected to the electrodes 24 and 34, respectively, but this connection is cut and the contacts 27 and 37 are connected to each other.
Of course, each can be used as an intermediate tap.

FIG. 5 shows a thermistor according to a third embodiment of the invention. Similar to the case in FIG. 3, a temperature-sensitive coating 42 made of silicon carbide, manganese-cobalt-iron oxide, etc. is coated on the surface of a substrate 41 made of alumina or the like.
are provided in a semicircular shape as shown in the figure by a method such as vapor deposition, sputtering vapor deposition, or screen printing. Metal electrode portions 43 and 44 are provided at both ends of this coating 42, and lead wires 45 and 46 are provided to the electrodes 43 and 44, respectively.
Next, as shown in the figure, a large number of metal terminal portions 47 are provided radially from above the coating 42 toward the vicinity of the center of the semicircular coating. The terminal portion 47 is provided, for example, by depositing gold, platinum, or the like by a method such as vapor deposition.
Next, a contact 48 that is rotated while contacting the metal terminal portion 47 is provided. The contact 48 is rotatably fixed to a stator 50 so as to be connected to a third electrode 49, and a lead wire 5 is attached to the electrode 49.
1 will be provided. The variable resistance thermistor constructed in this manner has even less noise and improved performance than the one shown in FIG. Note that the temperature-sensitive coating 42 can have a shape similar to that shown in FIG. In addition, if necessary, the portion of the coating 42 may be
It may be covered with an insulating film 52 made of silicon carbide, silicon oxide, or the like having insulating properties.

FIG. 6 shows a thermistor according to a fourth embodiment of the present invention. In this case, the configuration shown in FIG. 5 is modified to be horizontally elongated as shown in FIG.

Note that the symbols attached to each element in the figure are the same as those in FIG. 5, and the explanation thereof will be omitted.

Note that by varying the spacing between the terminal portions 47 in FIGS. 5 and 6, it is possible to easily obtain a desired resistance value.

The thermistor configured as described above not only simplifies the circuit but also provides excellent stability and reliability in temperature sensors and measurement systems.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of a temperature measurement system using a conventional thermistor, Figure 2 is a circuit diagram of a temperature measurement system using a thermistor according to the first embodiment of the present invention, and Figure 3 is a front view of the thermistor. Figure, Figure 4,
FIGS. 5 and 6 show the second, third, and third embodiments of the present invention, respectively.
It is a front view of the thermistor which is each 4th Example. 21, 31, 41...Substrate, 22, 32, 42
...temperature-sensitive coating, 23, 24, 33, 34, 38,
43, 44, 49... Electrode part, 27, 37, 47
...Contact child.

Claims (1)

[Claims] 1. A temperature-sensitive coating having a relatively wide area and a relatively narrow area is provided on an insulating substrate, and the temperature-sensitive coating is electrically connected to the temperature-sensitive coating at different positions on the temperature-sensitive coating. What is claimed is: 1. A thermistor comprising: a contact whose position can be moved so as to be connected; and a terminal for external extraction at at least one end of the temperature-sensitive coating and one end of the contact. 2. The thermistor according to claim 1, wherein the temperature-sensitive coating has a shape of a circumferential band or a straight band. 3. The thermistor according to claim 1, wherein the contacts are connected via a plurality of conductor pieces drawn out from the temperature-sensitive coating. 4. The thermistor according to claim 1, wherein the temperature-sensitive film is made of silicon carbide or manganese-cobalt-iron oxide. 5. The thermistor according to claim 3, wherein the surface of the temperature-sensitive film is covered with a film made of insulating silicon carbide or silicon oxide.